udp, udp_flow: Add instrumentation, handle EPOLLERR without queued errors

Link: https://github.com/containers/podman/issues/23686#issuecomment-2324945010
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

.clang-format

@@ -1,126 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0
-#
-# clang-format configuration file. Intended for clang-format >= 11.
-#
-# For more information, see:
-#
-#   Documentation/dev-tools/clang-format.rst
-#   https://clang.llvm.org/docs/ClangFormat.html
-#   https://clang.llvm.org/docs/ClangFormatStyleOptions.html
-#
----
-AccessModifierOffset: -4
-AlignAfterOpenBracket: Align
-AlignConsecutiveAssignments: false
-AlignConsecutiveDeclarations: false
-AlignEscapedNewlines: Left
-AlignOperands: true
-AlignTrailingComments: false
-AllowAllParametersOfDeclarationOnNextLine: false
-AllowShortBlocksOnASingleLine: false
-AllowShortCaseLabelsOnASingleLine: false
-AllowShortFunctionsOnASingleLine: None
-AllowShortIfStatementsOnASingleLine: false
-AllowShortLoopsOnASingleLine: false
-AlwaysBreakAfterDefinitionReturnType: None
-AlwaysBreakAfterReturnType: None
-AlwaysBreakBeforeMultilineStrings: false
-AlwaysBreakTemplateDeclarations: false
-BinPackArguments: true
-BinPackParameters: true
-BraceWrapping:
-  AfterClass: false
-  AfterControlStatement: false
-  AfterEnum: false
-  AfterFunction: true
-  AfterNamespace: true
-  AfterObjCDeclaration: false
-  AfterStruct: false
-  AfterUnion: false
-  AfterExternBlock: false
-  BeforeCatch: false
-  BeforeElse: false
-  IndentBraces: false
-  SplitEmptyFunction: true
-  SplitEmptyRecord: true
-  SplitEmptyNamespace: true
-BreakBeforeBinaryOperators: None
-BreakBeforeBraces: Custom
-BreakBeforeInheritanceComma: false
-BreakBeforeTernaryOperators: false
-BreakConstructorInitializersBeforeComma: false
-BreakConstructorInitializers: BeforeComma
-BreakAfterJavaFieldAnnotations: false
-BreakStringLiterals: false
-ColumnLimit: 80
-CommentPragmas: '^ IWYU pragma:'
-CompactNamespaces: false
-ConstructorInitializerAllOnOneLineOrOnePerLine: false
-ConstructorInitializerIndentWidth: 8
-ContinuationIndentWidth: 8
-Cpp11BracedListStyle: false
-DerivePointerAlignment: false
-DisableFormat: false
-ExperimentalAutoDetectBinPacking: false
-FixNamespaceComments: false
-
-# Taken from:
-#   git grep -h '^#define [^[:space:]]*for_each[^[:space:]]*(' include/ tools/ \
-#   | sed "s,^#define \([^[:space:]]*for_each[^[:space:]]*\)(.*$,  - '\1'," \
-#   | LC_ALL=C sort -u
-ForEachMacros:
-  - 'for_each_nst'
-
-IncludeBlocks: Preserve
-IncludeCategories:
-  - Regex: '.*'
-    Priority: 1
-IncludeIsMainRegex: '(Test)?$'
-IndentCaseLabels: false
-IndentGotoLabels: false
-IndentPPDirectives: None
-IndentWidth: 8
-IndentWrappedFunctionNames: false
-JavaScriptQuotes: Leave
-JavaScriptWrapImports: true
-KeepEmptyLinesAtTheStartOfBlocks: false
-MacroBlockBegin: ''
-MacroBlockEnd: ''
-MaxEmptyLinesToKeep: 1
-NamespaceIndentation: None
-ObjCBinPackProtocolList: Auto
-ObjCBlockIndentWidth: 8
-ObjCSpaceAfterProperty: true
-ObjCSpaceBeforeProtocolList: true
-
-# Taken from git's rules
-PenaltyBreakAssignment: 10
-PenaltyBreakBeforeFirstCallParameter: 30
-PenaltyBreakComment: 10
-PenaltyBreakFirstLessLess: 0
-PenaltyBreakString: 10
-PenaltyExcessCharacter: 100
-PenaltyReturnTypeOnItsOwnLine: 60
-
-PointerAlignment: Right
-ReflowComments: false
-SortIncludes: false
-SortUsingDeclarations: false
-SpaceAfterCStyleCast: false
-SpaceAfterTemplateKeyword: true
-SpaceBeforeAssignmentOperators: true
-SpaceBeforeCtorInitializerColon: true
-SpaceBeforeInheritanceColon: true
-SpaceBeforeParens: ControlStatementsExceptForEachMacros
-SpaceBeforeRangeBasedForLoopColon: true
-SpaceInEmptyParentheses: false
-SpacesBeforeTrailingComments: 1
-SpacesInAngles: false
-SpacesInContainerLiterals: false
-SpacesInCStyleCastParentheses: false
-SpacesInParentheses: false
-SpacesInSquareBrackets: false
-Standard: Cpp03
-TabWidth: 8
-UseTab: Always
-...

.clang-tidy

@@ -1,93 +0,0 @@
----
-Checks:
-    - "clang-diagnostic-*,clang-analyzer-*,*,-modernize-*"
-
-    #	TODO: enable once https://bugs.llvm.org/show_bug.cgi?id=41311 is fixed
-    - "-clang-analyzer-valist.Uninitialized"
-
-    #	Dubious value, would kill readability
-    - "-cppcoreguidelines-init-variables"
-
-    #	Dubious value over the compiler's built-in warning.  Would
-    #	increase verbosity.
-    - "-bugprone-assignment-in-if-condition"
-
-    #	Debatable whether these improve readability, right now it would look
-    #	like a mess
-    - "-google-readability-braces-around-statements"
-    - "-hicpp-braces-around-statements"
-    - "-readability-braces-around-statements"
-
-    #	TODO: in most cases they are justified, but probably not everywhere
-    #
-    - "-readability-magic-numbers"
-    - "-cppcoreguidelines-avoid-magic-numbers"
-
-    #	TODO: this is Linux-only for the moment, nice to fix eventually
-    - "-llvmlibc-restrict-system-libc-headers"
-
-    #	Those are needed for syscalls, epoll_wait flags, etc.
-    - "-hicpp-signed-bitwise"
-
-    #	Probably not doable to impement this without plain memcpy(), memset()
-    - "-clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling"
-
-    #	TODO: not really important, but nice to fix eventually
-    - "-llvm-include-order"
-
-    #	Dubious value, would kill readability
-    - "-readability-isolate-declaration"
-
-    #	TODO: nice to fix eventually
-    - "-bugprone-narrowing-conversions"
-    - "-cppcoreguidelines-narrowing-conversions"
-
-    #	TODO: check, fix, and more in general constify wherever possible
-    - "-cppcoreguidelines-avoid-non-const-global-variables"
-
-    #	TODO: check paths where it might make sense to improve performance
-    - "-altera-unroll-loops"
-    - "-altera-id-dependent-backward-branch"
-
-    #	Not much can be done about them other than being careful
-    - "-bugprone-easily-swappable-parameters"
-
-    #	TODO: split reported functions
-    - "-readability-function-cognitive-complexity"
-
-    #	"Poor" alignment needed for structs reflecting message formats/headers
-    - "-altera-struct-pack-align"
-
-    #	TODO: check again if multithreading is implemented
-    - "-concurrency-mt-unsafe"
-
-    #	Complains about any identifier <3 characters, reasonable for
-    #	globals, pointlessly verbose for locals and parameters.
-    - "-readability-identifier-length"
-
-    #	Wants to include headers which *directly* provide the things
-    #	we use.  That sounds nice, but means it will often want a OS
-    #	specific header instead of a mostly standard one, such as
-    #	<linux/limits.h> instead of <limits.h>.
-    - "-misc-include-cleaner"
-
-    #	Want to replace all #defines of integers with enums.  Kind of
-    #	makes sense when those defines form an enum-like set, but
-    #	weird for cases like standalone constants, and causes other
-    #	awkwardness for a bunch of cases we use
-    - "-cppcoreguidelines-macro-to-enum"
-
-    #	It's been a couple of centuries since multiplication has been granted
-    #	precedence over addition in modern mathematical notation. Adding
-    #	parentheses to reinforce that certainly won't improve readability.
-    - "-readability-math-missing-parentheses"
-WarningsAsErrors: "*"
-HeaderFileExtensions:
-    - h
-ImplementationFileExtensions:
-    - c
-HeaderFilterRegex: ""
-FormatStyle: none
-CheckOptions:
-    bugprone-suspicious-string-compare.WarnOnImplicitComparison: "false"
-SystemHeaders: false

.clangd

@@ -1,3 +0,0 @@
-CompileFlags:
-    # Don't try to interpret our headers as C++'
-    Add: [-xc, -Wall]

Makefile

@@ -15,11 +15,24 @@ VERSION ?= $(shell git describe --tags HEAD 2>/dev/null || echo "unknown\ versio
 # the IPv6 socket API? (Linux does)
 DUAL_STACK_SOCKETS := 1
 
+RLIMIT_STACK_VAL := $(shell /bin/sh -c 'ulimit -s')
+ifeq ($(RLIMIT_STACK_VAL),unlimited)
+RLIMIT_STACK_VAL := 1024
+endif
+
 TARGET ?= $(shell $(CC) -dumpmachine)
 # Get 'uname -m'-like architecture description for target
 TARGET_ARCH := $(shell echo $(TARGET) | cut -f1 -d- | tr [A-Z] [a-z])
 TARGET_ARCH := $(shell echo $(TARGET_ARCH) | sed 's/powerpc/ppc/')
 
+AUDIT_ARCH := $(shell echo $(TARGET_ARCH) | tr [a-z] [A-Z] | sed 's/^ARM.*/ARM/')
+AUDIT_ARCH := $(shell echo $(AUDIT_ARCH) | sed 's/I[456]86/I386/')
+AUDIT_ARCH := $(shell echo $(AUDIT_ARCH) | sed 's/PPC64/PPC/')
+AUDIT_ARCH := $(shell echo $(AUDIT_ARCH) | sed 's/PPCLE/PPC64LE/')
+AUDIT_ARCH := $(shell echo $(AUDIT_ARCH) | sed 's/MIPS64EL/MIPSEL64/')
+AUDIT_ARCH := $(shell echo $(AUDIT_ARCH) | sed 's/HPPA/PARISC/')
+AUDIT_ARCH := $(shell echo $(AUDIT_ARCH) | sed 's/SH4/SH/')
+
 # On some systems enabling optimization also enables source fortification,
 # automagically. Do not override it.
 FORTIFY_FLAG :=
@@ -31,6 +44,10 @@ FLAGS := -Wall -Wextra -Wno-format-zero-length
 FLAGS += -pedantic -std=c11 -D_XOPEN_SOURCE=700 -D_GNU_SOURCE
 FLAGS +=  $(FORTIFY_FLAG) -O2 -pie -fPIE
 FLAGS += -DPAGE_SIZE=$(shell getconf PAGE_SIZE)
+FLAGS += -DNETNS_RUN_DIR=\"/run/netns\"
+FLAGS += -DPASST_AUDIT_ARCH=AUDIT_ARCH_$(AUDIT_ARCH)
+FLAGS += -DRLIMIT_STACK_VAL=$(RLIMIT_STACK_VAL)
+FLAGS += -DARCH=\"$(TARGET_ARCH)\"
 FLAGS += -DVERSION=\"$(VERSION)\"
 FLAGS += -DDUAL_STACK_SOCKETS=$(DUAL_STACK_SOCKETS)
 
@@ -50,6 +67,21 @@ PASST_HEADERS = arch.h arp.h checksum.h conf.h dhcp.h dhcpv6.h flow.h fwd.h \
 	udp.h udp_flow.h util.h
 HEADERS = $(PASST_HEADERS) seccomp.h
 
+C := \#include <linux/tcp.h>\nstruct tcp_info x = { .tcpi_snd_wnd = 0 };
+ifeq ($(shell printf "$(C)" | $(CC) -S -xc - -o - >/dev/null 2>&1; echo $$?),0)
+	FLAGS += -DHAS_SND_WND
+endif
+
+C := \#include <linux/tcp.h>\nstruct tcp_info x = { .tcpi_bytes_acked = 0 };
+ifeq ($(shell printf "$(C)" | $(CC) -S -xc - -o - >/dev/null 2>&1; echo $$?),0)
+	FLAGS += -DHAS_BYTES_ACKED
+endif
+
+C := \#include <linux/tcp.h>\nstruct tcp_info x = { .tcpi_min_rtt = 0 };
+ifeq ($(shell printf "$(C)" | $(CC) -S -xc - -o - >/dev/null 2>&1; echo $$?),0)
+	FLAGS += -DHAS_MIN_RTT
+endif
+
 C := \#include <sys/random.h>\nint main(){int a=getrandom(0, 0, 0);}
 ifeq ($(shell printf "$(C)" | $(CC) -S -xc - -o - >/dev/null 2>&1; echo $$?),0)
 	FLAGS += -DHAS_GETRANDOM
@@ -59,6 +91,11 @@ ifeq ($(shell :|$(CC) -fstack-protector-strong -S -xc - -o - >/dev/null 2>&1; ec
 	FLAGS += -fstack-protector-strong
 endif
 
+C := \#define _GNU_SOURCE\n\#include <fcntl.h>\nint x = FALLOC_FL_COLLAPSE_RANGE;
+ifeq ($(shell printf "$(C)" | $(CC) -S -xc - -o - >/dev/null 2>&1; echo $$?),0)
+	EXTRA_SYSCALLS += fallocate
+endif
+
 prefix		?= /usr/local
 exec_prefix	?= $(prefix)
 bindir		?= $(exec_prefix)/bin
@@ -95,7 +132,7 @@ pasta.avx2 pasta.1 pasta: pasta%: passt%
 	ln -sf $< $@
 
 qrap: $(QRAP_SRCS) passt.h
-	$(CC) $(FLAGS) $(CFLAGS) $(CPPFLAGS) -DARCH=\"$(TARGET_ARCH)\" $(QRAP_SRCS) -o qrap $(LDFLAGS)
+	$(CC) $(FLAGS) $(CFLAGS) $(CPPFLAGS) $(QRAP_SRCS) -o qrap $(LDFLAGS)
 
 valgrind: EXTRA_SYSCALLS += rt_sigprocmask rt_sigtimedwait rt_sigaction	\
 			    rt_sigreturn getpid gettid kill clock_gettime mmap \
@@ -159,11 +196,116 @@ docs: README.md
 		done < README.md;					\
 	) > README.plain.md
 
-clang-tidy: $(PASST_SRCS) $(HEADERS)
+# Checkers currently disabled for clang-tidy:
-	clang-tidy $(PASST_SRCS) -- $(filter-out -pie,$(FLAGS) $(CFLAGS) $(CPPFLAGS)) \
+# - llvmlibc-restrict-system-libc-headers
-	           -DCLANG_TIDY_58992
+#	TODO: this is Linux-only for the moment, nice to fix eventually
+#
+# - google-readability-braces-around-statements
+# - hicpp-braces-around-statements
+# - readability-braces-around-statements
+#	Debatable whether that improves readability, right now it would look
+#	like a mess
+#
+# - readability-magic-numbers
+# - cppcoreguidelines-avoid-magic-numbers
+#	TODO: in most cases they are justified, but probably not everywhere
+#
+# - clang-analyzer-valist.Uninitialized
+#	TODO: enable once https://bugs.llvm.org/show_bug.cgi?id=41311 is fixed
+#
+# - clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling
+#	Probably not doable to impement this without plain memcpy(), memset()
+#
+# - cppcoreguidelines-init-variables
+#	Dubious value, would kill readability
+#
+# - hicpp-signed-bitwise
+#	Those are needed for syscalls, epoll_wait flags, etc.
+#
+# - llvm-include-order
+#	TODO: not really important, but nice to fix eventually
+#
+# - readability-isolate-declaration
+#	Dubious value, would kill readability
+#
+# - bugprone-narrowing-conversions
+# - cppcoreguidelines-narrowing-conversions
+#	TODO: nice to fix eventually
+#
+# - cppcoreguidelines-avoid-non-const-global-variables
+#	TODO: check, fix, and more in general constify wherever possible
+#
+# - altera-unroll-loops
+# - altera-id-dependent-backward-branch
+#	TODO: check paths where it might make sense to improve performance
+#
+# - bugprone-easily-swappable-parameters
+#	Not much can be done about them other than being careful
+#
+# - readability-function-cognitive-complexity
+#	TODO: split reported functions
+#
+# - altera-struct-pack-align
+#	"Poor" alignment needed for structs reflecting message formats/headers
+#
+# - concurrency-mt-unsafe
+#	TODO: check again if multithreading is implemented
+#
+# - readability-identifier-length
+#	Complains about any identifier <3 characters, reasonable for
+#	globals, pointlessly verbose for locals and parameters.
+#
+# - bugprone-assignment-in-if-condition
+#	Dubious value over the compiler's built-in warning.  Would
+#	increase verbosity.
+#
+# - misc-include-cleaner
+#	Wants to include headers which *directly* provide the things
+#	we use.  That sounds nice, but means it will often want a OS
+#	specific header instead of a mostly standard one, such as
+#	<linux/limits.h> instead of <limits.h>.
+#
+# - cppcoreguidelines-macro-to-enum
+#	Want to replace all #defines of integers with enums.  Kind of
+#	makes sense when those defines form an enum-like set, but
+#	weird for cases like standalone constants, and causes other
+#	awkwardness for a bunch of cases we use
 
-cppcheck: $(PASST_SRCS) $(HEADERS)
+clang-tidy: $(SRCS) $(HEADERS)
+	clang-tidy -checks=*,-modernize-*,\
+	-clang-analyzer-valist.Uninitialized,\
+	-cppcoreguidelines-init-variables,\
+	-bugprone-assignment-in-if-condition,\
+	-google-readability-braces-around-statements,\
+	-hicpp-braces-around-statements,\
+	-readability-braces-around-statements,\
+	-readability-magic-numbers,\
+	-llvmlibc-restrict-system-libc-headers,\
+	-hicpp-signed-bitwise,\
+	-clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling,\
+	-llvm-include-order,\
+	-cppcoreguidelines-avoid-magic-numbers,\
+	-readability-isolate-declaration,\
+	-bugprone-narrowing-conversions,\
+	-cppcoreguidelines-narrowing-conversions,\
+	-cppcoreguidelines-avoid-non-const-global-variables,\
+	-altera-unroll-loops,-altera-id-dependent-backward-branch,\
+	-bugprone-easily-swappable-parameters,\
+	-readability-function-cognitive-complexity,\
+	-altera-struct-pack-align,\
+	-concurrency-mt-unsafe,\
+	-readability-identifier-length,\
+	-misc-include-cleaner,\
+	-cppcoreguidelines-macro-to-enum \
+	-config='{CheckOptions: [{key: bugprone-suspicious-string-compare.WarnOnImplicitComparison, value: "false"}]}' \
+	--warnings-as-errors=* $(SRCS) -- $(filter-out -pie,$(FLAGS) $(CFLAGS) $(CPPFLAGS)) -DCLANG_TIDY_58992
+
+SYSTEM_INCLUDES := /usr/include $(wildcard /usr/include/$(TARGET))
+ifeq ($(shell $(CC) -v 2>&1 | grep -c "gcc version"),1)
+VER := $(shell $(CC) -dumpversion)
+SYSTEM_INCLUDES += /usr/lib/gcc/$(TARGET)/$(VER)/include
+endif
+cppcheck: $(SRCS) $(HEADERS)
 	if cppcheck --check-level=exhaustive /dev/null > /dev/null 2>&1; then \
 		CPPCHECK_EXHAUSTIVE="--check-level=exhaustive";		\
 	else								\
@@ -172,8 +314,11 @@ cppcheck: $(PASST_SRCS) $(HEADERS)
 	cppcheck --std=c11 --error-exitcode=1 --enable=all --force	\
 	--inconclusive --library=posix --quiet				\
 	$${CPPCHECK_EXHAUSTIVE}						\
+	$(SYSTEM_INCLUDES:%=-I%)					\
+	$(SYSTEM_INCLUDES:%=--config-exclude=%)				\
+	$(SYSTEM_INCLUDES:%=--suppress=*:%/*)				\
+	$(SYSTEM_INCLUDES:%=--suppress=unmatchedSuppression:%/*)	\
 	--inline-suppr							\
-	--suppress=missingIncludeSystem \
 	--suppress=unusedStructMember					\
-	$(filter -D%,$(FLAGS) $(CFLAGS) $(CPPFLAGS)) -D CPPCHECK_6936  \
+	$(filter -D%,$(FLAGS) $(CFLAGS) $(CPPFLAGS))			\
-	$(PASST_SRCS) $(HEADERS)
+	$(SRCS) $(HEADERS)

arch.c

@@ -19,7 +19,6 @@
 #include <unistd.h>
 
 #include "log.h"
-#include "util.h"
 
 /**
  * arch_avx2_exec() - Switch to AVX2 build if supported
@@ -41,11 +40,8 @@ void arch_avx2_exec(char **argv)
 	if (__builtin_cpu_supports("avx2")) {
 		char new_path[PATH_MAX + sizeof(".avx2")];
 
-		if (snprintf_check(new_path, PATH_MAX + sizeof(".avx2"),
+		snprintf(new_path, PATH_MAX + sizeof(".avx2"), "%s.avx2", exe);
-				   "%s.avx2", exe))
+		execve(new_path, argv, environ);
-			die_perror("Can't build AVX2 executable path");
-
-		execv(new_path, argv);
 		warn_perror("Can't run AVX2 build, using non-AVX2 version");
 	}
 }

arp.c

@@ -59,12 +59,14 @@ int arp(const struct ctx *c, const struct pool *p)
 	    ah->ar_op  != htons(ARPOP_REQUEST))
 		return 1;
 
-	/* Discard announcements, but not 0.0.0.0 "probes" */
+	/* Discard announcements (but not 0.0.0.0 "probes"): we might have the
-	if (memcmp(am->sip, &in4addr_any, sizeof(am->sip)) &&
+	 * same IP address, hide that.
+	 */
+	if (memcmp(am->sip, (unsigned char[4]){ 0 }, sizeof(am->tip)) &&
 	    !memcmp(am->sip, am->tip, sizeof(am->sip)))
 		return 1;
 
-	/* Don't resolve the guest's assigned address, either. */
+	/* Don't resolve our own address, either. */
 	if (!memcmp(am->tip, &c->ip4.addr, sizeof(am->tip)))
 		return 1;
 

checksum.c

@@ -59,7 +59,6 @@
 #include "util.h"
 #include "ip.h"
 #include "checksum.h"
-#include "iov.h"
 
 /* Checksums are optional for UDP over IPv4, so we usually just set
  * them to 0.  Change this to 1 to calculate real UDP over IPv4
@@ -166,24 +165,22 @@ uint32_t proto_ipv4_header_psum(uint16_t l4len, uint8_t protocol,
  * @udp4hr:	UDP header, initialised apart from checksum
  * @saddr:	IPv4 source address
  * @daddr:	IPv4 destination address
- * @iov:	Pointer to the array of IO vectors
+ * @payload:	UDP packet payload
- * @iov_cnt:	Length of the array
+ * @dlen:	Length of @payload (not including UDP header)
- * @offset:	UDP payload offset in the iovec array
  */
 void csum_udp4(struct udphdr *udp4hr,
 	       struct in_addr saddr, struct in_addr daddr,
-	       const struct iovec *iov, int iov_cnt, size_t offset)
+	       const void *payload, size_t dlen)
 {
 	/* UDP checksums are optional, so don't bother */
 	udp4hr->check = 0;
 
 	if (UDP4_REAL_CHECKSUMS) {
-		uint16_t l4len = iov_size(iov, iov_cnt) - offset +
+		uint16_t l4len = dlen + sizeof(struct udphdr);
-				 sizeof(struct udphdr);
 		uint32_t psum = proto_ipv4_header_psum(l4len, IPPROTO_UDP,
 						       saddr, daddr);
 		psum = csum_unfolded(udp4hr, sizeof(struct udphdr), psum);
-		udp4hr->check = csum_iov(iov, iov_cnt, offset, psum);
+		udp4hr->check = csum(payload, dlen, psum);
 	}
 }
 
@@ -229,24 +226,19 @@ uint32_t proto_ipv6_header_psum(uint16_t payload_len, uint8_t protocol,
 /**
  * csum_udp6() - Calculate and set checksum for a UDP over IPv6 packet
  * @udp6hr:	UDP header, initialised apart from checksum
- * @saddr:	Source address
+ * @payload:	UDP packet payload
- * @daddr:	Destination address
+ * @dlen:	Length of @payload (not including UDP header)
- * @iov:	Pointer to the array of IO vectors
- * @iov_cnt:	Length of the array
- * @offset:	UDP payload offset in the iovec array
  */
 void csum_udp6(struct udphdr *udp6hr,
 	       const struct in6_addr *saddr, const struct in6_addr *daddr,
-	       const struct iovec *iov, int iov_cnt, size_t offset)
+	       const void *payload, size_t dlen)
 {
-	uint16_t l4len = iov_size(iov, iov_cnt) - offset +
+	uint32_t psum = proto_ipv6_header_psum(dlen + sizeof(struct udphdr),
-			 sizeof(struct udphdr);
+					       IPPROTO_UDP, saddr, daddr);
-	uint32_t psum = proto_ipv6_header_psum(l4len, IPPROTO_UDP,
-					       saddr, daddr);
 	udp6hr->check = 0;
 
 	psum = csum_unfolded(udp6hr, sizeof(struct udphdr), psum);
-	udp6hr->check = csum_iov(iov, iov_cnt, offset, psum);
+	udp6hr->check = csum(payload, dlen, psum);
 }
 
 /**
@@ -505,26 +497,16 @@ uint16_t csum(const void *buf, size_t len, uint32_t init)
  *
  * @iov		Pointer to the array of IO vectors
  * @n		Length of the array
- * @offset:	Offset of the data to checksum within the full data length
  * @init	Initial 32-bit checksum, 0 for no pre-computed checksum
  *
  * Return: 16-bit folded, complemented checksum
  */
-uint16_t csum_iov(const struct iovec *iov, size_t n, size_t offset,
+/* cppcheck-suppress unusedFunction */
-		  uint32_t init)
+uint16_t csum_iov(const struct iovec *iov, size_t n, uint32_t init)
 {
 	unsigned int i;
-	size_t first;
 
-	i = iov_skip_bytes(iov, n, offset, &first);
+	for (i = 0; i < n; i++)
-	if (i >= n)
-		return (uint16_t)~csum_fold(init);
-
-	init = csum_unfolded((char *)iov[i].iov_base + first,
-			     iov[i].iov_len - first, init);
-	i++;
-
-	for (; i < n; i++)
 		init = csum_unfolded(iov[i].iov_base, iov[i].iov_len, init);
 
 	return (uint16_t)~csum_fold(init);

checksum.h

@@ -19,20 +19,19 @@ uint32_t proto_ipv4_header_psum(uint16_t l4len, uint8_t protocol,
 				struct in_addr saddr, struct in_addr daddr);
 void csum_udp4(struct udphdr *udp4hr,
 	       struct in_addr saddr, struct in_addr daddr,
-	       const struct iovec *iov, int iov_cnt, size_t offset);
+	       const void *payload, size_t dlen);
 void csum_icmp4(struct icmphdr *icmp4hr, const void *payload, size_t dlen);
 uint32_t proto_ipv6_header_psum(uint16_t payload_len, uint8_t protocol,
 				const struct in6_addr *saddr,
 				const struct in6_addr *daddr);
 void csum_udp6(struct udphdr *udp6hr,
 	       const struct in6_addr *saddr, const struct in6_addr *daddr,
-	       const struct iovec *iov, int iov_cnt, size_t offset);
+	       const void *payload, size_t dlen);
 void csum_icmp6(struct icmp6hdr *icmp6hr,
 		const struct in6_addr *saddr, const struct in6_addr *daddr,
 		const void *payload, size_t dlen);
 uint32_t csum_unfolded(const void *buf, size_t len, uint32_t init);
 uint16_t csum(const void *buf, size_t len, uint32_t init);
-uint16_t csum_iov(const struct iovec *iov, size_t n, size_t offset,
+uint16_t csum_iov(const struct iovec *iov, size_t n, uint32_t init);
-		  uint32_t init);
 
 #endif /* CHECKSUM_H */

conf.c

@@ -46,8 +46,6 @@
 #include "isolation.h"
 #include "log.h"
 
-#define NETNS_RUN_DIR	"/run/netns"
-
 /**
  * next_chunk - Return the next piece of a string delimited by a character
  * @s:		String to search
@@ -118,10 +116,11 @@ static int parse_port_range(const char *s, char **endptr,
 static void conf_ports(const struct ctx *c, char optname, const char *optarg,
 		       struct fwd_ports *fwd)
 {
-	union inany_addr addr_buf = inany_any6, *addr = &addr_buf;
+	char addr_buf[sizeof(struct in6_addr)] = { 0 }, *addr = addr_buf;
 	char buf[BUFSIZ], *spec, *ifname = NULL, *p;
 	bool exclude_only = true, bound_one = false;
 	uint8_t exclude[PORT_BITMAP_SIZE] = { 0 };
+	sa_family_t af = AF_UNSPEC;
 	unsigned i;
 	int ret;
 
@@ -167,13 +166,15 @@ static void conf_ports(const struct ctx *c, char optname, const char *optarg,
 
 			bitmap_set(fwd->map, i);
 			if (optname == 't') {
-				ret = tcp_sock_init(c, NULL, NULL, i);
+				ret = tcp_sock_init(c, AF_UNSPEC, NULL, NULL,
+						    i);
 				if (ret == -ENFILE || ret == -EMFILE)
 					goto enfile;
 				if (!ret)
 					bound_one = true;
 			} else if (optname == 'u') {
-				ret = udp_sock_init(c, 0, NULL, NULL, i);
+				ret = udp_sock_init(c, 0, AF_UNSPEC, NULL, NULL,
+						    i);
 				if (ret == -ENFILE || ret == -EMFILE)
 					goto enfile;
 				if (!ret)
@@ -225,7 +226,11 @@ static void conf_ports(const struct ctx *c, char optname, const char *optarg,
 				p++;
 			}
 
-			if (!inany_pton(p, addr))
+			if (inet_pton(AF_INET, p, addr))
+				af = AF_INET;
+			else if (inet_pton(AF_INET6, p, addr))
+				af = AF_INET6;
+			else
 				goto bad;
 		}
 	} else {
@@ -271,13 +276,13 @@ static void conf_ports(const struct ctx *c, char optname, const char *optarg,
 			bitmap_set(fwd->map, i);
 
 			if (optname == 't') {
-				ret = tcp_sock_init(c, addr, ifname, i);
+				ret = tcp_sock_init(c, af, addr, ifname, i);
 				if (ret == -ENFILE || ret == -EMFILE)
 					goto enfile;
 				if (!ret)
 					bound_one = true;
 			} else if (optname == 'u') {
-				ret = udp_sock_init(c, 0, addr, ifname, i);
+				ret = udp_sock_init(c, 0, af, addr, ifname, i);
 				if (ret == -ENFILE || ret == -EMFILE)
 					goto enfile;
 				if (!ret)
@@ -333,9 +338,9 @@ static void conf_ports(const struct ctx *c, char optname, const char *optarg,
 
 			ret = 0;
 			if (optname == 't')
-				ret = tcp_sock_init(c, addr, ifname, i);
+				ret = tcp_sock_init(c, af, addr, ifname, i);
 			else if (optname == 'u')
-				ret = udp_sock_init(c, 0, addr, ifname, i);
+				ret = udp_sock_init(c, 0, af, addr, ifname, i);
 			if (ret)
 				goto bind_fail;
 		}
@@ -576,15 +581,10 @@ static void conf_pasta_ns(int *netns_only, char *userns, char *netns,
 			if (pidval < 0 || pidval > INT_MAX)
 				die("Invalid PID %s", argv[optind]);
 
-			if (snprintf_check(netns, PATH_MAX,
+			snprintf(netns, PATH_MAX, "/proc/%ld/ns/net", pidval);
-					   "/proc/%ld/ns/net", pidval))
+			if (!*userns)
-				die_perror("Can't build netns path");
+				snprintf(userns, PATH_MAX, "/proc/%ld/ns/user",
-
+					 pidval);
-			if (!*userns) {
-				if (snprintf_check(userns, PATH_MAX,
-						   "/proc/%ld/ns/user", pidval))
-					die_perror("Can't build userns path");
-			}
 		}
 	}
 
@@ -735,19 +735,19 @@ static unsigned int conf_ip6(unsigned int ifi, struct ip6_ctx *ip6)
 static void usage(const char *name, FILE *f, int status)
 {
 	if (strstr(name, "pasta")) {
-		FPRINTF(f, "Usage: %s [OPTION]... [COMMAND] [ARGS]...\n", name);
+		fprintf(f, "Usage: %s [OPTION]... [COMMAND] [ARGS]...\n", name);
-		FPRINTF(f, "       %s [OPTION]... PID\n", name);
+		fprintf(f, "       %s [OPTION]... PID\n", name);
-		FPRINTF(f, "       %s [OPTION]... --netns [PATH|NAME]\n", name);
+		fprintf(f, "       %s [OPTION]... --netns [PATH|NAME]\n", name);
-		FPRINTF(f,
+		fprintf(f,
 			"\n"
 			"Without PID or --netns, run the given command or a\n"
 			"default shell in a new network and user namespace, and\n"
 			"connect it via pasta.\n");
 	} else {
-		FPRINTF(f, "Usage: %s [OPTION]...\n", name);
+		fprintf(f, "Usage: %s [OPTION]...\n", name);
 	}
 
-	FPRINTF(f,
+	fprintf(f,
 		"\n"
 		"  -d, --debug		Be verbose\n"
 		"      --trace		Be extra verbose, implies --debug\n"
@@ -764,17 +764,17 @@ static void usage(const char *name, FILE *f, int status)
 		"  --version		Show version and exit\n");
 
 	if (strstr(name, "pasta")) {
-		FPRINTF(f,
+		fprintf(f,
 			"  -I, --ns-ifname NAME	namespace interface name\n"
 			"    default: same interface name as external one\n");
 	} else {
-		FPRINTF(f,
+		fprintf(f,
 			"  -s, --socket PATH	UNIX domain socket path\n"
 			"    default: probe free path starting from "
 			UNIX_SOCK_PATH "\n", 1);
 	}
 
-	FPRINTF(f,
+	fprintf(f,
 		"  -F, --fd FD		Use FD as pre-opened connected socket\n"
 		"  -p, --pcap FILE	Log tap-facing traffic to pcap file\n"
 		"  -P, --pid FILE	Write own PID to the given file\n"
@@ -805,28 +805,28 @@ static void usage(const char *name, FILE *f, int status)
 		"    can be specified multiple times\n"
 		"    a single, empty option disables DNS information\n");
 	if (strstr(name, "pasta"))
-		FPRINTF(f, "    default: don't use any addresses\n");
+		fprintf(f, "    default: don't use any addresses\n");
 	else
-		FPRINTF(f, "    default: use addresses from /etc/resolv.conf\n");
+		fprintf(f, "    default: use addresses from /etc/resolv.conf\n");
-	FPRINTF(f,
+	fprintf(f,
 		"  -S, --search LIST	Space-separated list, search domains\n"
 		"    a single, empty option disables the DNS search list\n");
 	if (strstr(name, "pasta"))
-		FPRINTF(f, "    default: don't use any search list\n");
+		fprintf(f, "    default: don't use any search list\n");
 	else
-		FPRINTF(f, "    default: use search list from /etc/resolv.conf\n");
+		fprintf(f, "    default: use search list from /etc/resolv.conf\n");
 
 	if (strstr(name, "pasta"))
-		FPRINTF(f, "  --dhcp-dns	\tPass DNS list via DHCP/DHCPv6/NDP\n");
+		fprintf(f, "  --dhcp-dns	\tPass DNS list via DHCP/DHCPv6/NDP\n");
 	else
-		FPRINTF(f, "  --no-dhcp-dns	No DNS list in DHCP/DHCPv6/NDP\n");
+		fprintf(f, "  --no-dhcp-dns	No DNS list in DHCP/DHCPv6/NDP\n");
 
 	if (strstr(name, "pasta"))
-		FPRINTF(f, "  --dhcp-search	Pass list via DHCP/DHCPv6/NDP\n");
+		fprintf(f, "  --dhcp-search	Pass list via DHCP/DHCPv6/NDP\n");
 	else
-		FPRINTF(f, "  --no-dhcp-search	No list in DHCP/DHCPv6/NDP\n");
+		fprintf(f, "  --no-dhcp-search	No list in DHCP/DHCPv6/NDP\n");
 
-	FPRINTF(f,
+	fprintf(f,
 		"  --map-host-loopback ADDR	Translate ADDR to refer to host\n"
 	        "    can be specified zero to two times (for IPv4 and IPv6)\n"
 		"    default: gateway address\n"
@@ -836,9 +836,6 @@ static void usage(const char *name, FILE *f, int status)
 		"  --dns-forward ADDR	Forward DNS queries sent to ADDR\n"
 		"    can be specified zero to two times (for IPv4 and IPv6)\n"
 		"    default: don't forward DNS queries\n"
-		"  --dns-host ADDR	Host nameserver to direct queries to\n"
-		"    can be specified zero to two times (for IPv4 and IPv6)\n"
-		"    default: first nameserver from host's /etc/resolv.conf\n"
 		"  --no-tcp		Disable TCP protocol handler\n"
 		"  --no-udp		Disable UDP protocol handler\n"
 		"  --no-icmp		Disable ICMP/ICMPv6 protocol handler\n"
@@ -846,7 +843,6 @@ static void usage(const char *name, FILE *f, int status)
 		"  --no-ndp		Disable NDP responses\n"
 		"  --no-dhcpv6		Disable DHCPv6 server\n"
 		"  --no-ra		Disable router advertisements\n"
-		"  --freebind		Bind to any address for forwarding\n"
 		"  --no-map-gw		Don't map gateway address to host\n"
 		"  -4, --ipv4-only	Enable IPv4 operation only\n"
 		"  -6, --ipv6-only	Enable IPv6 operation only\n");
@@ -854,7 +850,7 @@ static void usage(const char *name, FILE *f, int status)
 	if (strstr(name, "pasta"))
 		goto pasta_opts;
 
-	FPRINTF(f,
+	fprintf(f,
 		"  -1, --one-off	Quit after handling one single client\n"
 		"  -t, --tcp-ports SPEC	TCP port forwarding to guest\n"
 		"    can be specified multiple times\n"
@@ -885,7 +881,7 @@ static void usage(const char *name, FILE *f, int status)
 
 pasta_opts:
 
-	FPRINTF(f,
+	fprintf(f,
 		"  -t, --tcp-ports SPEC	TCP port forwarding to namespace\n"
 		"    can be specified multiple times\n"
 		"    SPEC can be:\n"
@@ -919,9 +915,6 @@ pasta_opts:
 		"  -U, --udp-ns SPEC	UDP port forwarding to init namespace\n"
 		"    SPEC is as described above\n"
 		"    default: auto\n"
-		"  --host-lo-to-ns-lo	DEPRECATED:\n"
-		"			Translate host-loopback forwards to\n"
-		"			namespace loopback\n"
 		"  --userns NSPATH 	Target user namespace to join\n"
 		"  --netns PATH|NAME	Target network namespace to join\n"
 		"  --netns-only		Don't join existing user namespace\n"
@@ -1196,11 +1189,7 @@ static void conf_open_files(struct ctx *c)
 	if (c->mode != MODE_PASTA && c->fd_tap == -1)
 		c->fd_tap_listen = tap_sock_unix_open(c->sock_path);
 
-	if (*c->pidfile) {
+	c->pidfile_fd = pidfile_open(c->pidfile);
-		c->pidfile_fd = output_file_open(c->pidfile, O_WRONLY);
-		if (c->pidfile_fd < 0)
-			die_perror("Couldn't open PID file %s", c->pidfile);
-	}
 }
 
 /**
@@ -1273,7 +1262,6 @@ void conf(struct ctx *c, int argc, char **argv)
 		{"no-dhcpv6",	no_argument,		&c->no_dhcpv6,	1 },
 		{"no-ndp",	no_argument,		&c->no_ndp,	1 },
 		{"no-ra",	no_argument,		&c->no_ra,	1 },
-		{"freebind",	no_argument,		&c->freebind,	1 },
 		{"no-map-gw",	no_argument,		&no_map_gw,	1 },
 		{"ipv4-only",	no_argument,		NULL,		'4' },
 		{"ipv6-only",	no_argument,		NULL,		'6' },
@@ -1303,8 +1291,6 @@ void conf(struct ctx *c, int argc, char **argv)
 		{"netns-only",	no_argument,		NULL,		20 },
 		{"map-host-loopback", required_argument, NULL,		21 },
 		{"map-guest-addr", required_argument,	NULL,		22 },
-		{"host-lo-to-ns-lo", no_argument, 	NULL,		23 },
-		{"dns-host",	required_argument,	NULL,		24 },
 		{ 0 },
 	};
 	const char *logname = (c->mode == MODE_PASTA) ? "pasta" : "passt";
@@ -1427,9 +1413,9 @@ void conf(struct ctx *c, int argc, char **argv)
 
 			break;
 		case 14:
-			FPRINTF(stdout,
+			fprintf(stdout,
 				c->mode == MODE_PASTA ? "pasta " : "passt ");
-			FPRINTF(stdout, VERSION_BLOB);
+			fprintf(stdout, VERSION_BLOB);
 			exit(EXIT_SUCCESS);
 		case 15:
 			ret = snprintf(c->ip4.ifname_out,
@@ -1482,23 +1468,6 @@ void conf(struct ctx *c, int argc, char **argv)
 			conf_nat(optarg, &c->ip4.map_guest_addr,
 				 &c->ip6.map_guest_addr, NULL);
 			break;
-		case 23:
-			if (c->mode != MODE_PASTA)
-				die("--host-lo-to-ns-lo is for pasta mode only");
-			c->host_lo_to_ns_lo = 1;
-			break;
-		case 24:
-			if (inet_pton(AF_INET6, optarg, &c->ip6.dns_host) &&
-			    !IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns_host))
-				break;
-
-			if (inet_pton(AF_INET, optarg, &c->ip4.dns_host) &&
-			    !IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_host)   &&
-			    !IN4_IS_ADDR_BROADCAST(&c->ip4.dns_host))
-				break;
-
-			die("Invalid host nameserver address: %s", optarg);
-			break;
 		case 'd':
 			c->debug = 1;
 			c->quiet = 0;

contrib/apparmor/abstractions/passt

@@ -34,8 +34,6 @@
 
   owner @{PROC}/@{pid}/uid_map		r,	# conf_ugid()
 
-  @{PROC}/sys/net/ipv4/ip_local_port_range r,	# fwd_probe_ephemeral()
-
   network netlink raw,				# nl_sock_init_do(), netlink.c
 
   network inet stream,				# tcp.c

contrib/selinux/passt.te

@@ -50,7 +50,6 @@ require {
 	type passwd_file_t;
 
 	class netlink_route_socket { bind create nlmsg_read };
-	type sysctl_net_t;
 
 	class capability { sys_tty_config setuid setgid };
 	class cap_userns { setpcap sys_admin sys_ptrace };
@@ -105,8 +104,6 @@ allow passt_t net_conf_t:lnk_file read;
 allow passt_t tmp_t:sock_file { create unlink write };
 allow passt_t self:netlink_route_socket { bind create nlmsg_read read write setopt };
 kernel_search_network_sysctl(passt_t)
-allow passt_t sysctl_net_t:dir search;
-allow passt_t sysctl_net_t:file { open read };
 
 corenet_tcp_bind_all_nodes(passt_t)
 corenet_udp_bind_all_nodes(passt_t)

contrib/selinux/pasta.te

@@ -196,7 +196,7 @@ allow pasta_t ifconfig_var_run_t:dir { read search watch };
 allow pasta_t self:tun_socket create;
 allow pasta_t tun_tap_device_t:chr_file { ioctl open read write };
 allow pasta_t sysctl_net_t:dir search;
-allow pasta_t sysctl_net_t:file { open read write };
+allow pasta_t sysctl_net_t:file { open write };
 allow pasta_t kernel_t:system module_request;
 
 allow pasta_t nsfs_t:file read;

dhcpv6.c

@@ -296,42 +296,47 @@ static struct opt_hdr *dhcpv6_opt(const struct pool *p, size_t *offset,
 static struct opt_hdr *dhcpv6_ia_notonlink(const struct pool *p,
 					   struct in6_addr *la)
 {
-	int ia_types[2] = { OPT_IA_NA, OPT_IA_TA }, *ia_type;
-	const struct opt_ia_addr *opt_addr;
 	char buf[INET6_ADDRSTRLEN];
 	struct in6_addr req_addr;
 	const struct opt_hdr *h;
 	struct opt_hdr *ia;
 	size_t offset;
+	int ia_type;
 
-	foreach(ia_type, ia_types) {
+	ia_type = OPT_IA_NA;
-		offset = 0;
+ia_ta:
-		while ((ia = dhcpv6_opt(p, &offset, *ia_type))) {
+	offset = 0;
-			if (ntohs(ia->l) < OPT_VSIZE(ia_na))
+	while ((ia = dhcpv6_opt(p, &offset, ia_type))) {
+		if (ntohs(ia->l) < OPT_VSIZE(ia_na))
+			return NULL;
+
+		offset += sizeof(struct opt_ia_na);
+
+		while ((h = dhcpv6_opt(p, &offset, OPT_IAAADR))) {
+			const struct opt_ia_addr *opt_addr;
+
+			if (ntohs(h->l) != OPT_VSIZE(ia_addr))
 				return NULL;
 
-			offset += sizeof(struct opt_ia_na);
+			opt_addr = (const struct opt_ia_addr *)h;
-
+			req_addr = opt_addr->addr;
-			while ((h = dhcpv6_opt(p, &offset, OPT_IAAADR))) {
+			if (!IN6_ARE_ADDR_EQUAL(la, &req_addr)) {
-				if (ntohs(h->l) != OPT_VSIZE(ia_addr))
+				info("DHCPv6: requested address %s not on link",
-					return NULL;
+				     inet_ntop(AF_INET6, &req_addr,
-
+					       buf, sizeof(buf)));
-				opt_addr = (const struct opt_ia_addr *)h;
+				return ia;
-				req_addr = opt_addr->addr;
-				if (!IN6_ARE_ADDR_EQUAL(la, &req_addr))
-					goto err;
-
-				offset += sizeof(struct opt_ia_addr);
 			}
+
+			offset += sizeof(struct opt_ia_addr);
 		}
 	}
 
-	return NULL;
+	if (ia_type == OPT_IA_NA) {
+		ia_type = OPT_IA_TA;
+		goto ia_ta;
+	}
 
-err:
+	return NULL;
-	info("DHCPv6: requested address %s not on link",
-	     inet_ntop(AF_INET6, &req_addr, buf, sizeof(buf)));
-	return ia;
 }
 
 /**
@@ -423,11 +428,11 @@ search:
 int dhcpv6(struct ctx *c, const struct pool *p,
 	   const struct in6_addr *saddr, const struct in6_addr *daddr)
 {
-	const struct opt_hdr *client_id, *server_id, *ia;
+	struct opt_hdr *ia, *bad_ia, *client_id;
+	const struct opt_hdr *server_id;
 	const struct in6_addr *src;
 	const struct msg_hdr *mh;
 	const struct udphdr *uh;
-	struct opt_hdr *bad_ia;
 	size_t mlen, n;
 
 	uh = packet_get(p, 0, 0, sizeof(*uh), &mlen);

flow.c

@@ -283,23 +283,28 @@ void flow_log_(const struct flow_common *f, int pri, const char *fmt, ...)
 	       "Flow %u (%s): %s", flow_idx(f), type_or_state, msg);
 }
 
-/** flow_log_details_() - Log the details of a flow
+/**
- * @f:		flow to log
+ * flow_set_state() - Change flow's state
- * @pri:	Log priority
+ * @f:		Flow changing state
- * @state:	State to log details according to
+ * @state:	New state
- *
- * Logs the details of the flow: endpoints, interfaces, type etc.
  */
-void flow_log_details_(const struct flow_common *f, int pri,
+static void flow_set_state(struct flow_common *f, enum flow_state state)
-		       enum flow_state state)
 {
 	char estr0[INANY_ADDRSTRLEN], fstr0[INANY_ADDRSTRLEN];
 	char estr1[INANY_ADDRSTRLEN], fstr1[INANY_ADDRSTRLEN];
 	const struct flowside *ini = &f->side[INISIDE];
 	const struct flowside *tgt = &f->side[TGTSIDE];
+	uint8_t oldstate = f->state;
 
-	if (state >= FLOW_STATE_TGT)
+	ASSERT(state < FLOW_NUM_STATES);
-		flow_log_(f, pri,
+	ASSERT(oldstate < FLOW_NUM_STATES);
+
+	f->state = state;
+	flow_log_(f, LOG_DEBUG, "%s -> %s", flow_state_str[oldstate],
+		  FLOW_STATE(f));
+
+	if (MAX(state, oldstate) >= FLOW_STATE_TGT)
+		flow_log_(f, LOG_DEBUG,
 			  "%s [%s]:%hu -> [%s]:%hu => %s [%s]:%hu -> [%s]:%hu",
 			  pif_name(f->pif[INISIDE]),
 			  inany_ntop(&ini->eaddr, estr0, sizeof(estr0)),
@@ -311,8 +316,8 @@ void flow_log_details_(const struct flow_common *f, int pri,
 			  tgt->oport,
 			  inany_ntop(&tgt->eaddr, estr1, sizeof(estr1)),
 			  tgt->eport);
-	else if (state >= FLOW_STATE_INI)
+	else if (MAX(state, oldstate) >= FLOW_STATE_INI)
-		flow_log_(f, pri, "%s [%s]:%hu -> [%s]:%hu => ?",
+		flow_log_(f, LOG_DEBUG, "%s [%s]:%hu -> [%s]:%hu => ?",
 			  pif_name(f->pif[INISIDE]),
 			  inany_ntop(&ini->eaddr, estr0, sizeof(estr0)),
 			  ini->eport,
@@ -320,25 +325,6 @@ void flow_log_details_(const struct flow_common *f, int pri,
 			  ini->oport);
 }
 
-/**
- * flow_set_state() - Change flow's state
- * @f:		Flow changing state
- * @state:	New state
- */
-static void flow_set_state(struct flow_common *f, enum flow_state state)
-{
-	uint8_t oldstate = f->state;
-
-	ASSERT(state < FLOW_NUM_STATES);
-	ASSERT(oldstate < FLOW_NUM_STATES);
-
-	f->state = state;
-	flow_log_(f, LOG_DEBUG, "%s -> %s", flow_state_str[oldstate],
-		  FLOW_STATE(f));
-
-	flow_log_details_(f, LOG_DEBUG, MAX(state, oldstate));
-}
-
 /**
  * flow_initiate_() - Move flow to INI, setting pif[INISIDE]
  * @flow:	Flow to change state
@@ -711,7 +697,7 @@ static flow_sidx_t flowside_lookup(const struct ctx *c, uint8_t proto,
 	       !(FLOW_PROTO(&flow->f) == proto &&
 		 flow->f.pif[sidx.sidei] == pif &&
 		 flowside_eq(&flow->f.side[sidx.sidei], side)))
-		b = mod_sub(b, 1, FLOW_HASH_SIZE);
+		b = (b + 1) % FLOW_HASH_SIZE;
 
 	return flow_hashtab[b];
 }
@@ -846,8 +832,7 @@ void flow_defer_handler(const struct ctx *c, const struct timespec *now)
 				closed = icmp_ping_timer(c, &flow->ping, now);
 			break;
 		case FLOW_UDP:
-			closed = udp_flow_defer(&flow->udp);
+			if (timer)
-			if (!closed && timer)
 				closed = udp_flow_timer(c, &flow->udp, now);
 			break;
 		default:

flow.h

@@ -264,11 +264,4 @@ void flow_log_(const struct flow_common *f, int pri, const char *fmt, ...)
 			flow_dbg((f), __VA_ARGS__);			\
 	} while (0)
 
-void flow_log_details_(const struct flow_common *f, int pri,
-		       enum flow_state state);
-#define flow_log_details(f_, pri) \
-	flow_log_details_(&((f_)->f), (pri), (f_)->f.state)
-#define flow_dbg_details(f_)	flow_log_details((f_), LOG_DEBUG)
-#define flow_err_details(f_)	flow_log_details((f_), LOG_ERR)
-
 #endif /* FLOW_H */

flow_table.h

@@ -110,7 +110,7 @@ static inline const struct flowside *flowside_at_sidx(flow_sidx_t sidx)
 	const union flow *flow = flow_at_sidx(sidx);
 
 	if (!flow)
-		return NULL;
+		return PIF_NONE;
 
 	return &flow->f.side[sidx.sidei];
 }

fwd.c

@@ -75,8 +75,8 @@ void fwd_probe_ephemeral(void)
 	if (*end || errno)
 		goto parse_err;
 
-	if (min < 0 || min >= (long)NUM_PORTS ||
+	if (min < 0 || min >= NUM_PORTS ||
-	    max < 0 || max >= (long)NUM_PORTS)
+	    max < 0 || max >= NUM_PORTS)
 		goto parse_err;
 
 	fwd_ephemeral_min = min;
@@ -447,35 +447,20 @@ uint8_t fwd_nat_from_host(const struct ctx *c, uint8_t proto,
 	    (proto == IPPROTO_TCP || proto == IPPROTO_UDP)) {
 		/* spliceable */
 
-		/* The traffic will go over the guest's 'lo' interface, but by
+		/* Preserve the specific loopback adddress used, but let the
-		 * default use its external address, so we don't inadvertently
+		 * kernel pick a source port on the target side
-		 * expose services that listen only on the guest's loopback
-		 * address.  That can be overridden by --host-lo-to-ns-lo which
-		 * will instead forward to the loopback address in the guest.
-		 *
-		 * In either case, let the kernel pick the source address to
-		 * match.
 		 */
-		if (inany_v4(&ini->eaddr)) {
+		tgt->oaddr = ini->eaddr;
-			if (c->host_lo_to_ns_lo)
-				tgt->eaddr = inany_loopback4;
-			else
-				tgt->eaddr = inany_from_v4(c->ip4.addr_seen);
-			tgt->oaddr = inany_any4;
-		} else {
-			if (c->host_lo_to_ns_lo)
-				tgt->eaddr = inany_loopback6;
-			else
-				tgt->eaddr.a6 = c->ip6.addr_seen;
-			tgt->oaddr = inany_any6;
-		}
-
-		/* Let the kernel pick source port */
 		tgt->oport = 0;
 		if (proto == IPPROTO_UDP)
 			/* But for UDP preserve the source port */
 			tgt->oport = ini->eport;
 
+		if (inany_v4(&ini->eaddr))
+			tgt->eaddr = inany_loopback4;
+		else
+			tgt->eaddr = inany_loopback6;
+
 		return PIF_SPLICE;
 	}
 

inany.c

@@ -36,23 +36,3 @@ const char *inany_ntop(const union inany_addr *src, char *dst, socklen_t size)
 
 	return inet_ntop(AF_INET6, &src->a6, dst, size);
 }
-
-/** inany_pton - Parse an IPv[46] address from text format
- * @src:	IPv[46] address
- * @dst:	output buffer, filled with parsed address
- *
- * Return: On success, 1, if no parseable address is found, 0
- */
-int inany_pton(const char *src, union inany_addr *dst)
-{
-	if (inet_pton(AF_INET, src, &dst->v4mapped.a4)) {
-		memset(&dst->v4mapped.zero, 0, sizeof(dst->v4mapped.zero));
-		memset(&dst->v4mapped.one, 0xff, sizeof(dst->v4mapped.one));
-		return 1;
-	}
-
-	if (inet_pton(AF_INET6, src, &dst->a6))
-		return 1;
-
-	return 0;
-}

inany.h

@@ -270,6 +270,5 @@ static inline void inany_siphash_feed(struct siphash_state *state,
 #define INANY_ADDRSTRLEN	MAX(INET_ADDRSTRLEN, INET6_ADDRSTRLEN)
 
 const char *inany_ntop(const union inany_addr *src, char *dst, socklen_t size);
-int inany_pton(const char *src, union inany_addr *dst);
 
 #endif /* INANY_H */

linux_dep.h

@@ -1,144 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later
- * Copyright Red Hat
- *
- * Declarations for Linux specific dependencies
- */
-
-#ifndef LINUX_DEP_H
-#define LINUX_DEP_H
-
-/* struct tcp_info_linux - Information from Linux TCP_INFO getsockopt()
- *
- * Largely derived from include/linux/tcp.h in the Linux kernel
- *
- * Some fields returned by TCP_INFO have been there for ages and are shared with
- * BSD.  struct tcp_info from netinet/tcp.h has only those fields.  There are
- * also a many Linux specific extensions to the structure, which are only found
- * in the linux/tcp.h version of struct tcp_info.
- *
- * We want to use some of those extension fields, when available.  We can test
- * for availability in the runtime kernel using the length returned from
- * getsockopt(). However, we won't necessarily be compiled against the same
- * kernel headers as we'll run with, so compiling directly against linux/tcp.h
- * means wrapping every field access in an #ifdef whose #else does the same
- * thing as when the field is missing at runtime.  This rapidly gets messy.
- *
- * Instead we define here struct tcp_info_linux which includes all the Linux
- * extensions that we want to use.  This is taken from v6.11 of the kernel.
- */
-struct tcp_info_linux {
-	uint8_t		tcpi_state;
-	uint8_t		tcpi_ca_state;
-	uint8_t		tcpi_retransmits;
-	uint8_t		tcpi_probes;
-	uint8_t		tcpi_backoff;
-	uint8_t		tcpi_options;
-	uint8_t		tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
-	uint8_t		tcpi_delivery_rate_app_limited:1, tcpi_fastopen_client_fail:2;
-
-	uint32_t	tcpi_rto;
-	uint32_t	tcpi_ato;
-	uint32_t	tcpi_snd_mss;
-	uint32_t	tcpi_rcv_mss;
-
-	uint32_t	tcpi_unacked;
-	uint32_t	tcpi_sacked;
-	uint32_t	tcpi_lost;
-	uint32_t	tcpi_retrans;
-	uint32_t	tcpi_fackets;
-
-	/* Times. */
-	uint32_t	tcpi_last_data_sent;
-	uint32_t	tcpi_last_ack_sent;
-	uint32_t	tcpi_last_data_recv;
-	uint32_t	tcpi_last_ack_recv;
-
-	/* Metrics. */
-	uint32_t	tcpi_pmtu;
-	uint32_t	tcpi_rcv_ssthresh;
-	uint32_t	tcpi_rtt;
-	uint32_t	tcpi_rttvar;
-	uint32_t	tcpi_snd_ssthresh;
-	uint32_t	tcpi_snd_cwnd;
-	uint32_t	tcpi_advmss;
-	uint32_t	tcpi_reordering;
-
-	uint32_t	tcpi_rcv_rtt;
-	uint32_t	tcpi_rcv_space;
-
-	uint32_t	tcpi_total_retrans;
-
-	/* Linux extensions */
-	uint64_t	tcpi_pacing_rate;
-	uint64_t	tcpi_max_pacing_rate;
-	uint64_t	tcpi_bytes_acked;    /* RFC4898 tcpEStatsAppHCThruOctetsAcked */
-	uint64_t	tcpi_bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived */
-	uint32_t	tcpi_segs_out;	     /* RFC4898 tcpEStatsPerfSegsOut */
-	uint32_t	tcpi_segs_in;	     /* RFC4898 tcpEStatsPerfSegsIn */
-
-	uint32_t	tcpi_notsent_bytes;
-	uint32_t	tcpi_min_rtt;
-	uint32_t	tcpi_data_segs_in;	/* RFC4898 tcpEStatsDataSegsIn */
-	uint32_t	tcpi_data_segs_out;	/* RFC4898 tcpEStatsDataSegsOut */
-
-	uint64_t	tcpi_delivery_rate;
-
-	uint64_t	tcpi_busy_time;      /* Time (usec) busy sending data */
-	uint64_t	tcpi_rwnd_limited;   /* Time (usec) limited by receive window */
-	uint64_t	tcpi_sndbuf_limited; /* Time (usec) limited by send buffer */
-
-	uint32_t	tcpi_delivered;
-	uint32_t	tcpi_delivered_ce;
-
-	uint64_t	tcpi_bytes_sent;     /* RFC4898 tcpEStatsPerfHCDataOctetsOut */
-	uint64_t	tcpi_bytes_retrans;  /* RFC4898 tcpEStatsPerfOctetsRetrans */
-	uint32_t	tcpi_dsack_dups;     /* RFC4898 tcpEStatsStackDSACKDups */
-	uint32_t	tcpi_reord_seen;     /* reordering events seen */
-
-	uint32_t	tcpi_rcv_ooopack;    /* Out-of-order packets received */
-
-	uint32_t	tcpi_snd_wnd;	     /* peer's advertised receive window after
-					      * scaling (bytes)
-					      */
-	uint32_t	tcpi_rcv_wnd;	     /* local advertised receive window after
-					      * scaling (bytes)
-					      */
-
-	uint32_t 	tcpi_rehash;         /* PLB or timeout triggered rehash attempts */
-
-	uint16_t	tcpi_total_rto;	/* Total number of RTO timeouts, including
-					 * SYN/SYN-ACK and recurring timeouts.
-					 */
-	uint16_t	tcpi_total_rto_recoveries;	/* Total number of RTO
-							 * recoveries, including any
-							 * unfinished recovery.
-							 */
-	uint32_t	tcpi_total_rto_time;	/* Total time spent in RTO recoveries
-						 * in milliseconds, including any
-						 * unfinished recovery.
-						 */
-};
-
-#include <linux/falloc.h>
-
-#ifndef FALLOC_FL_COLLAPSE_RANGE
-#define FALLOC_FL_COLLAPSE_RANGE	0x08
-#endif
-
-#include <linux/close_range.h>
-
-/* glibc < 2.34 and musl as of 1.2.5 need these */
-#ifndef SYS_close_range
-#define SYS_close_range		436
-#endif
-#ifndef CLOSE_RANGE_UNSHARE	/* Linux kernel < 5.9 */
-#define CLOSE_RANGE_UNSHARE	(1U << 1)
-#endif
-
-__attribute__ ((weak))
-/* cppcheck-suppress funcArgNamesDifferent */
-int close_range(unsigned int first, unsigned int last, int flags) {
-	return syscall(SYS_close_range, first, last, flags);
-}
-
-#endif /* LINUX_DEP_H */

log.c

@@ -26,7 +26,6 @@
 #include <stdarg.h>
 #include <sys/socket.h>
 
-#include "linux_dep.h"
 #include "log.h"
 #include "util.h"
 #include "passt.h"
@@ -93,6 +92,7 @@ const char *logfile_prefix[] = {
 	"         ",		/* LOG_DEBUG */
 };
 
+#ifdef FALLOC_FL_COLLAPSE_RANGE
 /**
  * logfile_rotate_fallocate() - Write header, set log_written after fallocate()
  * @fd:		Log file descriptor
@@ -126,6 +126,7 @@ static void logfile_rotate_fallocate(int fd, const struct timespec *now)
 
 	log_written -= log_cut_size;
 }
+#endif /* FALLOC_FL_COLLAPSE_RANGE */
 
 /**
  * logfile_rotate_move() - Fallback: move recent entries toward start, then cut
@@ -197,17 +198,21 @@ out:
  *
  * Return: 0 on success, negative error code on failure
  *
- * #syscalls fcntl fallocate
+ * #syscalls fcntl
+ *
+ * fallocate() passed as EXTRA_SYSCALL only if FALLOC_FL_COLLAPSE_RANGE is there
  */
 static int logfile_rotate(int fd, const struct timespec *now)
 {
 	if (fcntl(fd, F_SETFL, O_RDWR /* Drop O_APPEND: explicit lseek() */))
 		return -errno;
 
+#ifdef FALLOC_FL_COLLAPSE_RANGE
 	/* Only for Linux >= 3.15, extent-based ext4 or XFS, glibc >= 2.18 */
 	if (!fallocate(fd, FALLOC_FL_COLLAPSE_RANGE, 0, log_cut_size))
 		logfile_rotate_fallocate(fd, now);
 	else
+#endif
 		logfile_rotate_move(fd, now);
 
 	if (fcntl(fd, F_SETFL, O_RDWR | O_APPEND))
@@ -269,7 +274,7 @@ void vlogmsg(bool newline, bool cont, int pri, const char *format, va_list ap)
 		char timestr[LOGTIME_STRLEN];
 
 		logtime_fmt(timestr, sizeof(timestr), now);
-		FPRINTF(stderr, "%s: ", timestr);
+		fprintf(stderr, "%s: ", timestr);
 	}
 
 	if ((log_mask & LOG_MASK(LOG_PRI(pri))) || !log_conf_parsed) {
@@ -288,7 +293,7 @@ void vlogmsg(bool newline, bool cont, int pri, const char *format, va_list ap)
 	    (log_stderr && (log_mask & LOG_MASK(LOG_PRI(pri))))) {
 		(void)vfprintf(stderr, format, ap);
 		if (newline && format[strlen(format)] != '\n')
-			FPRINTF(stderr, "\n");
+			fprintf(stderr, "\n");
 	}
 }
 
@@ -394,7 +399,7 @@ void passt_vsyslog(bool newline, int pri, const char *format, va_list ap)
 		n += snprintf(buf + n, BUFSIZ - n, "\n");
 
 	if (log_sock >= 0 && send(log_sock, buf, n, 0) != n && log_stderr)
-		FPRINTF(stderr, "Failed to send %i bytes to syslog\n", n);
+		fprintf(stderr, "Failed to send %i bytes to syslog\n", n);
 }
 
 /**
@@ -411,7 +416,8 @@ void logfile_init(const char *name, const char *path, size_t size)
 	if (readlink("/proc/self/exe", exe, PATH_MAX - 1) < 0)
 		die_perror("Failed to read own /proc/self/exe link");
 
-	log_file = output_file_open(path, O_APPEND | O_RDWR);
+	log_file = open(path, O_CREAT | O_TRUNC | O_APPEND | O_RDWR | O_CLOEXEC,
+			S_IRUSR | S_IWUSR);
 	if (log_file == -1)
 		die_perror("Couldn't open log file %s", path);
 
@@ -427,3 +433,4 @@ void logfile_init(const char *name, const char *path, size_t size)
 	/* For FALLOC_FL_COLLAPSE_RANGE: VFS block size can be up to one page */
 	log_cut_size = ROUND_UP(log_size * LOGFILE_CUT_RATIO / 100, PAGE_SIZE);
 }
+

ndp.c

@@ -234,8 +234,8 @@ int ndp(struct ctx *c, const struct icmp6hdr *ih, const struct in6_addr *saddr,
 		return 1;
 
 	if (ih->icmp6_type == NS) {
-		const struct ndp_ns *ns =
+		struct ndp_ns *ns = packet_get(p, 0, 0, sizeof(struct ndp_ns),
-			packet_get(p, 0, 0, sizeof(struct ndp_ns), NULL);
+					       NULL);
 
 		if (!ns)
 			return -1;

netlink.c

@@ -353,7 +353,7 @@ unsigned int nl_get_ext_if(int s, sa_family_t af)
  */
 bool nl_route_get_def_multipath(struct rtattr *rta, void *gw)
 {
-	int nh_len = RTA_PAYLOAD(rta);
+	size_t nh_len = RTA_PAYLOAD(rta);
 	struct rtnexthop *rtnh;
 	bool found = false;
 	int hops = -1;
@@ -582,7 +582,7 @@ int nl_route_dup(int s_src, unsigned int ifi_src,
 
 				*(unsigned int *)RTA_DATA(rta) = ifi_dst;
 			} else if (rta->rta_type == RTA_MULTIPATH) {
-				int nh_len = RTA_PAYLOAD(rta);
+				size_t nh_len = RTA_PAYLOAD(rta);
 				struct rtnexthop *rtnh;
 
 				for (rtnh = (struct rtnexthop *)RTA_DATA(rta);

passt.1

@@ -95,7 +95,7 @@ detached PID namespace after starting, because the PID itself cannot change.
 Default is to fork into background.
 
 .TP
-.BR \-e ", " \-\-stderr " " (DEPRECATED)
+.BR \-e ", " \-\-stderr
 This option has no effect, and is maintained for compatibility purposes only.
 
 Note that this configuration option is \fBdeprecated\fR and will be removed in a
@@ -249,19 +249,10 @@ the host.
 .TP
 .BR \-\-dns-forward " " \fIaddr
 Map \fIaddr\fR (IPv4 or IPv6) as seen from guest or namespace to the
-nameserver (with corresponding IP version) specified by the
+first configured DNS resolver (with corresponding IP version). Maps
-\fB\-\-dns-host\fR option. Maps only UDP and TCP traffic to port 53 or
+only UDP and TCP traffic to port 53 or port 853.  Replies are
-port 853.  Replies are translated back with a reverse mapping.  This
+translated back with a reverse mapping.  This option can be specified
-option can be specified zero to two times (once for IPv4, once for
+zero to two times (once for IPv4, once for IPv6).
-IPv6).
-
-.TP
-.BR \-\-dns-host " " \fIaddr
-Configure the host nameserver which guest or namespace queries to the
-\fB\-\-dns-forward\fR address will be redirected to. This option can
-be specified zero to two times (once for IPv4, once for IPv6).
-By default, the first nameserver from the host's
-\fI/etc/resolv.conf\fR.
 
 .TP
 .BR \-S ", " \-\-search " " \fIlist
@@ -336,16 +327,6 @@ namespace will be silently dropped.
 Disable Router Advertisements. Router Solicitations coming from guest or target
 namespace will be ignored.
 
-.TP
-.BR \-\-freebind
-Allow any binding address to be specified for \fB-t\fR and \fB-u\fR
-options.  Usually binding addresses must be addresses currently
-configured on the host.  With \fB\-\-freebind\fR, the
-\fBIP_FREEBIND\fR or \fBIPV6_FREEBIND\fR socket option is enabled
-allowing any address to be used.  This is typically used to bind
-addresses which might be configured on the host in future, at which
-point the forwarding will immediately start operating.
-
 .TP
 .BR \-\-map-host-loopback " " \fIaddr
 Translate \fIaddr\fR to refer to the host. Packets from the guest to
@@ -605,13 +586,6 @@ Configure UDP port forwarding from target namespace to init namespace.
 
 Default is \fBauto\fR.
 
-.TP
-.BR \-\-host-lo-to-ns-lo " " (DEPRECATED)
-If specified, connections forwarded with \fB\-t\fR and \fB\-u\fR from
-the host's loopback address will appear on the loopback address in the
-guest as well.  Without this option such forwarded packets will appear
-to come from the guest's public address.
-
 .TP
 .BR \-\-userns " " \fIspec
 Target user namespace to join, as a path. If PID is given, without this option,
@@ -889,41 +863,38 @@ root@localhost's password:
 
 .SH NOTES
 
-.SS Handling of traffic with loopback destination and source addresses
+.SS Handling of traffic with local destination and source addresses
 
-Both \fBpasst\fR and \fBpasta\fR can bind on ports with a loopback
+Both \fBpasst\fR and \fBpasta\fR can bind on ports with a local address,
-address (127.0.0.0/8 or ::1), depending on the configuration. Loopback
+depending on the configuration. Local destination or source addresses need to be
-destination or source addresses need to be changed before packets are
+changed before packets are delivered to the guest or target namespace: most
-delivered to the guest or target namespace: most operating systems
+operating systems would drop packets received from non-loopback interfaces with
-would drop packets received with loopback addresses on non-loopback
+local addresses, and it would also be impossible for guest or target namespace
-interfaces, and it would also be impossible for guest or target
+to route answers back.
-namespace to route answers back.
 
-For convenience, the source address on these packets is translated to
+For convenience, and somewhat arbitrarily, the source address on these packets
-the address specified by the \fB\-\-map-host-loopback\fR option (with
+is translated to the address of the default IPv4 or IPv6 gateway (if any) --
-some exceptions in pasta mode, see next section below).  If not
+this is known to be an existing, valid address on the same subnet.
-specified this defaults, somewhat arbitrarily, to the address of
-default IPv4 or IPv6 gateway (if any) -- this is known to be an
-existing, valid address on the same subnet.  If \fB\-\-no-map-gw\fR or
-\fB\-\-map-host-loopback none\fR are specified this translation is
-disabled and packets with loopback addresses are simply dropped.
 
-Loopback destination addresses are translated to the observed external
+Loopback destination addresses are instead translated to the observed external
-address of the guest or target namespace. For IPv6, the observed
+address of the guest or target namespace. For IPv6 packets, if usage of a
-link-local address is used if the translated source address is
+link-local address by guest or namespace has ever been observed, and the
-link-local, otherwise the observed global address is used. For both
+original destination address is also a link-local address, the observed
-IPv4 and IPv6, if no addresses have been seen yet, the configured
+link-local address is used. Otherwise, the observed global address is used. For
-addresses will be used instead.
+both IPv4 and IPv6, if no addresses have been seen yet, the configured addresses
+will be used instead.
 
 For example, if \fBpasst\fR or \fBpasta\fR receive a connection from 127.0.0.1,
 with destination 127.0.0.10, and the default IPv4 gateway is 192.0.2.1, while
 the last observed source address from guest or namespace is 192.0.2.2, this will
 be translated to a connection from 192.0.2.1 to 192.0.2.2.
 
-Similarly, for traffic coming from guest or namespace, packets with
+Similarly, for traffic coming from guest or namespace, packets with destination
-destination address corresponding to the \fB\-\-map-host-loopback\fR
+address corresponding to the default gateway will have their destination address
-address will have their destination address translated to a loopback
+translated to a loopback address, if and only if a packet, in the opposite
-address.
+direction, with a loopback destination or source address, port-wise matching for
+UDP, or connection-wise for TCP, has been recently forwarded to guest or
+namespace. This behaviour can be disabled with \-\-no\-map\-gw.
 
 .SS Handling of local traffic in pasta
 
@@ -939,15 +910,8 @@ and the new socket using the \fBsplice\fR(2) system call, and for UDP, a pair
 of \fBrecvmmsg\fR(2) and \fBsendmmsg\fR(2) system calls deals with packet
 transfers.
 
-Because it's not possible to bind sockets to foreign addresses, this
+This bypass only applies to local connections and traffic, because it's not
-bypass only applies to local connections and traffic.  It also means
+possible to bind sockets to foreign addresses.
-that the address translation differs slightly from passt mode.
-Connections from loopback to loopback on the host will appear to come
-from the target namespace's public address within the guest, unless
-\fB\-\-host-lo-to-ns-lo\fR is specified, in which case they will
-appear to come from loopback in the namespace as well.  The latter
-behaviour used to be the default, but is usually undesirable, since it
-can unintentionally expose namespace local services to the host.
 
 .SS Binding to low numbered ports (well-known or system ports, up to 1023)
 

passt.c

@@ -207,8 +207,7 @@ int main(int argc, char **argv)
 	struct timespec now;
 	struct sigaction sa;
 
-	if (clock_gettime(CLOCK_MONOTONIC, &log_start))
+	clock_gettime(CLOCK_MONOTONIC, &log_start);
-		die_perror("Failed to get CLOCK_MONOTONIC time");
 
 	arch_avx2_exec(argv);
 
@@ -266,8 +265,7 @@ int main(int argc, char **argv)
 
 	secret_init(&c);
 
-	if (clock_gettime(CLOCK_MONOTONIC, &now))
+	clock_gettime(CLOCK_MONOTONIC, &now);
-		die_perror("Failed to get CLOCK_MONOTONIC time");
 
 	flow_init();
 
@@ -309,15 +307,13 @@ int main(int argc, char **argv)
 	timer_init(&c, &now);
 
 loop:
-	/* NOLINTBEGIN(bugprone-branch-clone): intervals can be the same */
+	/* NOLINTNEXTLINE(bugprone-branch-clone): intervals can be the same */
 	/* cppcheck-suppress [duplicateValueTernary, unmatchedSuppression] */
 	nfds = epoll_wait(c.epollfd, events, EPOLL_EVENTS, TIMER_INTERVAL);
-	/* NOLINTEND(bugprone-branch-clone) */
 	if (nfds == -1 && errno != EINTR)
 		die_perror("epoll_wait() failed in main loop");
 
-	if (clock_gettime(CLOCK_MONOTONIC, &now))
+	clock_gettime(CLOCK_MONOTONIC, &now);
-		err_perror("Failed to get CLOCK_MONOTONIC time");
 
 	for (i = 0; i < nfds; i++) {
 		union epoll_ref ref = *((union epoll_ref *)&events[i].data.u64);

passt.h

@@ -225,8 +225,6 @@ struct ip6_ctx {
  * @no_dhcpv6:		Disable DHCPv6 server
  * @no_ndp:		Disable NDP handler altogether
  * @no_ra:		Disable router advertisements
- * @host_lo_to_ns_lo:	Map host loopback addresses to ns loopback addresses
- * @freebind:		Allow binding of non-local addresses for forwarding
  * @low_wmem:		Low probed net.core.wmem_max
  * @low_rmem:		Low probed net.core.rmem_max
  */
@@ -286,8 +284,6 @@ struct ctx {
 	int no_dhcpv6;
 	int no_ndp;
 	int no_ra;
-	int host_lo_to_ns_lo;
-	int freebind;
 
 	int low_wmem;
 	int low_rmem;

pasta.c

@@ -102,9 +102,7 @@ static int pasta_wait_for_ns(void *arg)
 	int flags = O_RDONLY | O_CLOEXEC;
 	char ns[PATH_MAX];
 
-	if (snprintf_check(ns, PATH_MAX, "/proc/%i/ns/net", pasta_child_pid))
+	snprintf(ns, PATH_MAX, "/proc/%i/ns/net", pasta_child_pid);
-		die_perror("Can't build netns path");
-
 	do {
 		while ((c->pasta_netns_fd = open(ns, flags)) < 0) {
 			if (errno != ENOENT)
@@ -241,11 +239,8 @@ void pasta_start_ns(struct ctx *c, uid_t uid, gid_t gid,
 		c->quiet = 1;
 
 	/* Configure user and group mappings */
-	if (snprintf_check(uidmap, BUFSIZ, "0 %u 1", uid))
+	snprintf(uidmap, BUFSIZ, "0 %u 1", uid);
-		die_perror("Can't build uidmap");
+	snprintf(gidmap, BUFSIZ, "0 %u 1", gid);
-
-	if (snprintf_check(gidmap, BUFSIZ, "0 %u 1", gid))
-		die_perror("Can't build gidmap");
 
 	if (write_file("/proc/self/uid_map", uidmap) ||
 	    write_file("/proc/self/setgroups", "deny") ||
@@ -432,12 +427,12 @@ static int pasta_netns_quit_timer(void)
  */
 void pasta_netns_quit_init(const struct ctx *c)
 {
+	union epoll_ref ref = { .type = EPOLL_TYPE_NSQUIT_INOTIFY };
 	struct epoll_event ev = { .events = EPOLLIN };
 	int flags = O_NONBLOCK | O_CLOEXEC;
 	struct statfs s = { 0 };
 	bool try_inotify = true;
 	int fd = -1, dir_fd;
-	union epoll_ref ref;
 
 	if (c->mode != MODE_PASTA || c->no_netns_quit || !*c->netns_base)
 		return;
@@ -468,7 +463,6 @@ void pasta_netns_quit_init(const struct ctx *c)
 		ref.type = EPOLL_TYPE_NSQUIT_TIMER;
 	} else {
 		close(dir_fd);
-		ref.type = EPOLL_TYPE_NSQUIT_INOTIFY;
 	}
 
 	if (fd > FD_REF_MAX)

pcap.c

@@ -86,8 +86,9 @@ static void pcap_frame(const struct iovec *iov, size_t iovcnt,
 		.caplen = l2len,
 		.len = l2len
 	};
+	struct iovec hiov = { &h, sizeof(h) };
 
-	if (write_all_buf(pcap_fd, &h, sizeof(h)) < 0 ||
+	if (write_remainder(pcap_fd, &hiov, 1, 0) < 0 ||
 	    write_remainder(pcap_fd, iov, iovcnt, offset) < 0)
 		debug_perror("Cannot log packet, length %zu", l2len);
 }
@@ -100,14 +101,12 @@ static void pcap_frame(const struct iovec *iov, size_t iovcnt,
 void pcap(const char *pkt, size_t l2len)
 {
 	struct iovec iov = { (char *)pkt, l2len };
-	struct timespec now = { 0 };
+	struct timespec now;
 
 	if (pcap_fd == -1)
 		return;
 
-	if (clock_gettime(CLOCK_REALTIME, &now))
+	clock_gettime(CLOCK_REALTIME, &now);
-		err_perror("Failed to get CLOCK_REALTIME time");
-
 	pcap_frame(&iov, 1, 0, &now);
 }
 
@@ -121,14 +120,13 @@ void pcap(const char *pkt, size_t l2len)
 void pcap_multiple(const struct iovec *iov, size_t frame_parts, unsigned int n,
 		   size_t offset)
 {
-	struct timespec now = { 0 };
+	struct timespec now;
 	unsigned int i;
 
 	if (pcap_fd == -1)
 		return;
 
-	if (clock_gettime(CLOCK_REALTIME, &now))
+	clock_gettime(CLOCK_REALTIME, &now);
-		err_perror("Failed to get CLOCK_REALTIME time");
 
 	for (i = 0; i < n; i++)
 		pcap_frame(iov + i * frame_parts, frame_parts, offset, &now);
@@ -141,20 +139,17 @@ void pcap_multiple(const struct iovec *iov, size_t frame_parts, unsigned int n,
  * @iov:	Pointer to the array of struct iovec describing the I/O vector
  *		containing packet data to write, including L2 header
  * @iovcnt:	Number of buffers (@iov entries)
- * @offset:	Offset of the L2 frame within the full data length
  */
 /* cppcheck-suppress unusedFunction */
-void pcap_iov(const struct iovec *iov, size_t iovcnt, size_t offset)
+void pcap_iov(const struct iovec *iov, size_t iovcnt)
 {
-	struct timespec now = { 0 };
+	struct timespec now;
 
 	if (pcap_fd == -1)
 		return;
 
-	if (clock_gettime(CLOCK_REALTIME, &now))
+	clock_gettime(CLOCK_REALTIME, &now);
-		err_perror("Failed to get CLOCK_REALTIME time");
+	pcap_frame(iov, iovcnt, 0, &now);
-
-	pcap_frame(iov, iovcnt, offset, &now);
 }
 
 /**
@@ -163,15 +158,18 @@ void pcap_iov(const struct iovec *iov, size_t iovcnt, size_t offset)
  */
 void pcap_init(struct ctx *c)
 {
+	int flags = O_WRONLY | O_CREAT | O_TRUNC;
+
 	if (pcap_fd != -1)
 		return;
 
 	if (!*c->pcap)
 		return;
 
-	pcap_fd = output_file_open(c->pcap, O_WRONLY);
+	flags |= c->foreground ? O_CLOEXEC : 0;
+	pcap_fd = open(c->pcap, flags, S_IRUSR | S_IWUSR);
 	if (pcap_fd == -1) {
-		err_perror("Couldn't open pcap file %s", c->pcap);
+		perror("open");
 		return;
 	}
 

pcap.h

@@ -9,7 +9,7 @@
 void pcap(const char *pkt, size_t l2len);
 void pcap_multiple(const struct iovec *iov, size_t frame_parts, unsigned int n,
 		   size_t offset);
-void pcap_iov(const struct iovec *iov, size_t iovcnt, size_t offset);
+void pcap_iov(const struct iovec *iov, size_t iovcnt);
 void pcap_init(struct ctx *c);
 
 #endif /* PCAP_H */

pif.c

@@ -59,45 +59,3 @@ void pif_sockaddr(const struct ctx *c, union sockaddr_inany *sa, socklen_t *sl,
 		*sl = sizeof(sa->sa6);
 	}
 }
-
-/** pif_sock_l4() - Open a socket bound to an address on a specified interface
- * @c:		Execution context
- * @type:	Socket epoll type
- * @pif:	Interface for this socket
- * @addr:	Address to bind to, or NULL for dual-stack any
- * @ifname:	Interface for binding, NULL for any
- * @port:	Port number to bind to (host byte order)
- * @data:	epoll reference portion for protocol handlers
- *
- * NOTE: For namespace pifs, this must be called having already entered the
- * relevant namespace.
- *
- * Return: newly created socket, negative error code on failure
- */
-int pif_sock_l4(const struct ctx *c, enum epoll_type type, uint8_t pif,
-		const union inany_addr *addr, const char *ifname,
-		in_port_t port, uint32_t data)
-{
-	union sockaddr_inany sa = {
-		.sa6.sin6_family = AF_INET6,
-		.sa6.sin6_addr = in6addr_any,
-		.sa6.sin6_port = htons(port),
-	};
-	socklen_t sl;
-
-	ASSERT(pif_is_socket(pif));
-
-	if (pif == PIF_SPLICE) {
-		/* Sanity checks */
-		ASSERT(!ifname);
-		ASSERT(addr && inany_is_loopback(addr));
-	}
-
-	if (!addr)
-		return sock_l4_sa(c, type, &sa, sizeof(sa.sa6),
-				  ifname, false, data);
-
-	pif_sockaddr(c, &sa, &sl, pif, addr, port);
-	return sock_l4_sa(c, type, &sa, sl,
-			  ifname, sa.sa_family == AF_INET6, data);
-}

pif.h

@@ -59,8 +59,5 @@ static inline bool pif_is_socket(uint8_t pif)
 
 void pif_sockaddr(const struct ctx *c, union sockaddr_inany *sa, socklen_t *sl,
 		  uint8_t pif, const union inany_addr *addr, in_port_t port);
-int pif_sock_l4(const struct ctx *c, enum epoll_type type, uint8_t pif,
-		const union inany_addr *addr, const char *ifname,
-		in_port_t port, uint32_t data);
 
 #endif /* PIF_H */

seccomp.sh

@@ -20,15 +20,6 @@ OUT="$(mktemp)"
 [ -z "${ARCH}" ] && ARCH="$(uname -m)"
 [ -z "${CC}" ] && CC="cc"
 
-AUDIT_ARCH="AUDIT_ARCH_$(echo ${ARCH} | tr [a-z] [A-Z]             \
-                                      | sed 's/^ARM.*/ARM/'        \
-                                      | sed 's/I[456]86/I386/'     \
-                                      | sed 's/PPC64/PPC/'         \
-                                      | sed 's/PPCLE/PPC64LE/'     \
-                                      | sed 's/MIPS64EL/MIPSEL64/' \
-                                      | sed 's/HPPA/PARISC/'       \
-                                      | sed 's/SH4/SH/')"
-
 HEADER="/* This file was automatically generated by $(basename ${0}) */
 
 #ifndef AUDIT_ARCH_PPC64LE
@@ -41,7 +32,7 @@ struct sock_filter filter_@PROFILE@[] = {
 	/* cppcheck-suppress [badBitmaskCheck, unmatchedSuppression] */
 	BPF_STMT(BPF_LD | BPF_W | BPF_ABS,
 		 (offsetof(struct seccomp_data, arch))),
-	BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, @AUDIT_ARCH@, 0, @KILL@),
+	BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, PASST_AUDIT_ARCH, 0, @KILL@),
 	/* cppcheck-suppress [badBitmaskCheck, unmatchedSuppression] */
 	BPF_STMT(BPF_LD | BPF_W | BPF_ABS,
 		 (offsetof(struct seccomp_data, nr))),
@@ -242,8 +233,7 @@ gen_profile() {
 		sub ${__i} CALL "NR:${__nr}" "NAME:${__name}" "ALLOW:${__allow}"
 	done
 
-	finish PRE "PROFILE:${__profile}" "KILL:$(( __statements + 1))" \
+	finish PRE "PROFILE:${__profile}" "KILL:$(( __statements + 1))"
-	       "AUDIT_ARCH:${AUDIT_ARCH}"
 }
 
 printf '%s\n' "${HEADER}" > "${OUT}"

tap.c

@@ -172,15 +172,11 @@ void tap_udp4_send(const struct ctx *c, struct in_addr src, in_port_t sport,
 	struct iphdr *ip4h = tap_push_l2h(c, buf, ETH_P_IP);
 	struct udphdr *uh = tap_push_ip4h(ip4h, src, dst, l4len, IPPROTO_UDP);
 	char *data = (char *)(uh + 1);
-	const struct iovec iov = {
-		.iov_base = (void *)in,
-		.iov_len = dlen
-	};
 
 	uh->source = htons(sport);
 	uh->dest = htons(dport);
 	uh->len = htons(l4len);
-	csum_udp4(uh, src, dst, &iov, 1, 0);
+	csum_udp4(uh, src, dst, in, dlen);
 	memcpy(data, in, dlen);
 
 	tap_send_single(c, buf, dlen + (data - buf));
@@ -251,7 +247,7 @@ static void *tap_push_ip6h(struct ipv6hdr *ip6h,
 void tap_udp6_send(const struct ctx *c,
 		   const struct in6_addr *src, in_port_t sport,
 		   const struct in6_addr *dst, in_port_t dport,
-		   uint32_t flow, void *in, size_t dlen)
+		   uint32_t flow, const void *in, size_t dlen)
 {
 	size_t l4len = dlen + sizeof(struct udphdr);
 	char buf[USHRT_MAX];
@@ -259,15 +255,11 @@ void tap_udp6_send(const struct ctx *c,
 	struct udphdr *uh = tap_push_ip6h(ip6h, src, dst,
 					  l4len, IPPROTO_UDP, flow);
 	char *data = (char *)(uh + 1);
-	const struct iovec iov = {
-		.iov_base = in,
-		.iov_len = dlen
-	};
 
 	uh->source = htons(sport);
 	uh->dest = htons(dport);
 	uh->len = htons(l4len);
-	csum_udp6(uh, src, dst, &iov, 1, 0);
+	csum_udp6(uh, src, dst, in, dlen);
 	memcpy(data, in, dlen);
 
 	tap_send_single(c, buf, dlen + (data - buf));
@@ -990,17 +982,24 @@ static void tap_sock_reset(struct ctx *c)
 }
 
 /**
- * tap_passt_input() - Handler for new data on the socket to qemu
+ * tap_handler_passt() - Packet handler for AF_UNIX file descriptor
  * @c:		Execution context
+ * @events:	epoll events
  * @now:	Current timestamp
  */
-static void tap_passt_input(struct ctx *c, const struct timespec *now)
+void tap_handler_passt(struct ctx *c, uint32_t events,
+		       const struct timespec *now)
 {
 	static const char *partial_frame;
 	static ssize_t partial_len = 0;
 	ssize_t n;
 	char *p;
 
+	if (events & (EPOLLRDHUP | EPOLLHUP | EPOLLERR)) {
+		tap_sock_reset(c);
+		return;
+	}
+
 	tap_flush_pools();
 
 	if (partial_len) {
@@ -1011,13 +1010,10 @@ static void tap_passt_input(struct ctx *c, const struct timespec *now)
 		memmove(pkt_buf, partial_frame, partial_len);
 	}
 
-	do {
+	n = recv(c->fd_tap, pkt_buf + partial_len, TAP_BUF_BYTES - partial_len,
-		n = recv(c->fd_tap, pkt_buf + partial_len,
+		 MSG_DONTWAIT);
-			 TAP_BUF_BYTES - partial_len, MSG_DONTWAIT);
-	} while ((n < 0) && errno == EINTR);
-
 	if (n < 0) {
-		if (errno != EAGAIN && errno != EWOULDBLOCK) {
+		if (errno != EINTR && errno != EAGAIN && errno != EWOULDBLOCK) {
 			err_perror("Receive error on guest connection, reset");
 			tap_sock_reset(c);
 		}
@@ -1055,63 +1051,6 @@ static void tap_passt_input(struct ctx *c, const struct timespec *now)
 	tap_handler(c, now);
 }
 
-/**
- * tap_handler_passt() - Event handler for AF_UNIX file descriptor
- * @c:		Execution context
- * @events:	epoll events
- * @now:	Current timestamp
- */
-void tap_handler_passt(struct ctx *c, uint32_t events,
-		       const struct timespec *now)
-{
-	if (events & (EPOLLRDHUP | EPOLLHUP | EPOLLERR)) {
-		tap_sock_reset(c);
-		return;
-	}
-
-	if (events & EPOLLIN)
-		tap_passt_input(c, now);
-}
-
-/**
- * tap_pasta_input() - Handler for new data on the socket to hypervisor
- * @c:		Execution context
- * @now:	Current timestamp
- */
-static void tap_pasta_input(struct ctx *c, const struct timespec *now)
-{
-	ssize_t n, len;
-
-	tap_flush_pools();
-
-	for (n = 0; n <= (ssize_t)(TAP_BUF_BYTES - ETH_MAX_MTU); n += len) {
-		len = read(c->fd_tap, pkt_buf + n, ETH_MAX_MTU);
-
-		if (len == 0) {
-			die("EOF on tap device, exiting");
-		} else if (len < 0) {
-			if (errno == EINTR) {
-				len = 0;
-				continue;
-			}
-
-			if (errno == EAGAIN && errno == EWOULDBLOCK)
-				break; /* all done for now */
-
-			die("Error on tap device, exiting");
-		}
-
-		/* Ignore frames of bad length */
-		if (len < (ssize_t)sizeof(struct ethhdr) ||
-		    len > (ssize_t)ETH_MAX_MTU)
-			continue;
-
-		tap_add_packet(c, len, pkt_buf + n);
-	}
-
-	tap_handler(c, now);
-}
-
 /**
  * tap_handler_pasta() - Packet handler for /dev/net/tun file descriptor
  * @c:		Execution context
@@ -1121,11 +1060,46 @@ static void tap_pasta_input(struct ctx *c, const struct timespec *now)
 void tap_handler_pasta(struct ctx *c, uint32_t events,
 		       const struct timespec *now)
 {
+	ssize_t n, len;
+	int ret;
+
 	if (events & (EPOLLRDHUP | EPOLLHUP | EPOLLERR))
 		die("Disconnect event on /dev/net/tun device, exiting");
 
-	if (events & EPOLLIN)
+redo:
-		tap_pasta_input(c, now);
+	n = 0;
+
+	tap_flush_pools();
+restart:
+	while ((len = read(c->fd_tap, pkt_buf + n, TAP_BUF_BYTES - n)) > 0) {
+
+		if (len < (ssize_t)sizeof(struct ethhdr) ||
+		    len > (ssize_t)ETH_MAX_MTU) {
+			n += len;
+			continue;
+		}
+
+
+		tap_add_packet(c, len, pkt_buf + n);
+
+		if ((n += len) == TAP_BUF_BYTES)
+			break;
+	}
+
+	if (len < 0 && errno == EINTR)
+		goto restart;
+
+	ret = errno;
+
+	tap_handler(c, now);
+
+	if (len > 0 || ret == EAGAIN)
+		return;
+
+	if (n == TAP_BUF_BYTES)
+		goto redo;
+
+	die("Error on tap device, exiting");
 }
 
 /**
@@ -1136,7 +1110,7 @@ void tap_handler_pasta(struct ctx *c, uint32_t events,
  */
 int tap_sock_unix_open(char *sock_path)
 {
-	int fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
+	int fd = socket(AF_UNIX, SOCK_STREAM, 0);
 	struct sockaddr_un addr = {
 		.sun_family = AF_UNIX,
 	};
@@ -1151,12 +1125,10 @@ int tap_sock_unix_open(char *sock_path)
 
 		if (*sock_path)
 			memcpy(path, sock_path, UNIX_PATH_MAX);
-		else if (snprintf_check(path, UNIX_PATH_MAX - 1,
+		else
-					UNIX_SOCK_PATH, i))
+			snprintf(path, UNIX_PATH_MAX - 1, UNIX_SOCK_PATH, i);
-			die_perror("Can't build UNIX domain socket path");
 
-		ex = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC,
+		ex = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0);
-			    0);
 		if (ex < 0)
 			die_perror("Failed to check for UNIX domain conflicts");
 
@@ -1289,7 +1261,7 @@ static int tap_ns_tun(void *arg)
 	if (fd < 0)
 		die_perror("Failed to open() /dev/net/tun");
 
-	rc = ioctl(fd, (int)TUNSETIFF, &ifr);
+	rc = ioctl(fd, TUNSETIFF, &ifr);
 	if (rc < 0)
 		die_perror("TUNSETIFF ioctl on /dev/net/tun failed");
 

tap.h

@@ -53,7 +53,7 @@ const struct in6_addr *tap_ip6_daddr(const struct ctx *c,
 void tap_udp6_send(const struct ctx *c,
 		   const struct in6_addr *src, in_port_t sport,
 		   const struct in6_addr *dst, in_port_t dport,
-		   uint32_t flow, void *in, size_t dlen);
+		   uint32_t flow, const void *in, size_t dlen);
 void tap_icmp6_send(const struct ctx *c,
 		    const struct in6_addr *src, const struct in6_addr *dst,
 		    const void *in, size_t l4len);

tcp.c

@@ -274,7 +274,6 @@
 #include <net/if.h>
 #include <netinet/in.h>
 #include <netinet/ip.h>
-#include <netinet/tcp.h>
 #include <stdint.h>
 #include <stdbool.h>
 #include <stddef.h>
@@ -287,6 +286,8 @@
 #include <time.h>
 #include <arpa/inet.h>
 
+#include <linux/tcp.h> /* For struct tcp_info */
+
 #include "checksum.h"
 #include "util.h"
 #include "iov.h"
@@ -299,7 +300,6 @@
 #include "log.h"
 #include "inany.h"
 #include "flow.h"
-#include "linux_dep.h"
 
 #include "flow_table.h"
 #include "tcp_internal.h"
@@ -308,6 +308,11 @@
 /* MSS rounding: see SET_MSS() */
 #define MSS_DEFAULT			536
 #define WINDOW_DEFAULT			14600		/* RFC 6928 */
+#ifdef HAS_SND_WND
+# define KERNEL_REPORTS_SND_WND(c)	((c)->tcp.kernel_snd_wnd)
+#else
+# define KERNEL_REPORTS_SND_WND(c)	(0 && (c))
+#endif
 
 #define ACK_INTERVAL			10		/* ms */
 #define SYN_TIMEOUT			10		/* s */
@@ -318,6 +323,11 @@
 #define LOW_RTT_TABLE_SIZE		8
 #define LOW_RTT_THRESHOLD		10 /* us */
 
+/* We need to include <linux/tcp.h> for tcpi_bytes_acked, instead of
+ * <netinet/tcp.h>, but that doesn't include a definition for SOL_TCP
+ */
+#define SOL_TCP				IPPROTO_TCP
+
 #define ACK_IF_NEEDED	0		/* See tcp_send_flag() */
 
 #define CONN_IS_CLOSING(conn)						\
@@ -361,20 +371,6 @@ char		tcp_buf_discard		[MAX_WINDOW];
 /* Does the kernel support TCP_PEEK_OFF? */
 bool peek_offset_cap;
 
-/* Size of data returned by TCP_INFO getsockopt() */
-socklen_t tcp_info_size;
-
-#define tcp_info_cap(f_)						\
-	((offsetof(struct tcp_info_linux, tcpi_##f_) +			\
-	  sizeof(((struct tcp_info_linux *)NULL)->tcpi_##f_)) <= tcp_info_size)
-
-/* Kernel reports sending window in TCP_INFO (kernel commit 8f7baad7f035) */
-#define snd_wnd_cap	tcp_info_cap(snd_wnd)
-/* Kernel reports bytes acked in TCP_INFO (kernel commit 0df48c26d84) */
-#define bytes_acked_cap	tcp_info_cap(bytes_acked)
-/* Kernel reports minimum RTT in TCP_INFO (kernel commit cd9b266095f4) */
-#define min_rtt_cap	tcp_info_cap(min_rtt)
-
 /* sendmsg() to socket */
 static struct iovec	tcp_iov			[UIO_MAXIOV];
 
@@ -428,23 +424,27 @@ int tcp_set_peek_offset(int s, int offset)
  */
 static uint32_t tcp_conn_epoll_events(uint8_t events, uint8_t conn_flags)
 {
+	uint32_t rdhup;
+
 	if (!events)
 		return 0;
 
+	rdhup = (events & SOCK_FIN_RCVD) ? 0 : EPOLLRDHUP;
+
 	if (events & ESTABLISHED) {
 		if (events & TAP_FIN_SENT)
 			return EPOLLET;
 
 		if (conn_flags & STALLED)
-			return EPOLLIN | EPOLLOUT | EPOLLRDHUP | EPOLLET;
+			return EPOLLIN | EPOLLOUT | rdhup | EPOLLET;
 
-		return EPOLLIN | EPOLLRDHUP;
+		return EPOLLIN | rdhup;
 	}
 
 	if (events == TAP_SYN_RCVD)
-		return EPOLLOUT | EPOLLET | EPOLLRDHUP;
+		return EPOLLOUT | EPOLLET | rdhup;
 
-	return EPOLLET | EPOLLRDHUP;
+	return rdhup;
 }
 
 /**
@@ -549,8 +549,7 @@ static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn)
 		 (unsigned long long)it.it_value.tv_sec,
 		 (unsigned long long)it.it_value.tv_nsec / 1000 / 1000);
 
-	if (timerfd_settime(conn->timer, 0, &it, NULL))
+	timerfd_settime(conn->timer, 0, &it, NULL);
-		flow_err(conn, "failed to set timer: %s", strerror(errno));
 }
 
 /**
@@ -680,12 +679,13 @@ static int tcp_rtt_dst_low(const struct tcp_tap_conn *conn)
  * @tinfo:	Pointer to struct tcp_info for socket
  */
 static void tcp_rtt_dst_check(const struct tcp_tap_conn *conn,
-			      const struct tcp_info_linux *tinfo)
+			      const struct tcp_info *tinfo)
 {
+#ifdef HAS_MIN_RTT
 	const struct flowside *tapside = TAPFLOW(conn);
 	int i, hole = -1;
 
-	if (!min_rtt_cap ||
+	if (!tinfo->tcpi_min_rtt ||
 	    (int)tinfo->tcpi_min_rtt > LOW_RTT_THRESHOLD)
 		return;
 
@@ -706,6 +706,10 @@ static void tcp_rtt_dst_check(const struct tcp_tap_conn *conn,
 	if (hole == LOW_RTT_TABLE_SIZE)
 		hole = 0;
 	inany_from_af(low_rtt_dst + hole, AF_INET6, &in6addr_any);
+#else
+	(void)conn;
+	(void)tinfo;
+#endif /* HAS_MIN_RTT */
 }
 
 /**
@@ -752,106 +756,34 @@ static void tcp_sock_set_bufsize(const struct ctx *c, int s)
 }
 
 /**
- * tcp_update_check_tcp4() - Calculate TCP checksum for IPv4
+ * tcp_update_check_tcp4() - Update TCP checksum from stored one
  * @iph:	IPv4 header
- * @iov:	Pointer to the array of IO vectors
+ * @th:		TCP header followed by TCP payload
- * @iov_cnt:	Length of the array
- * @l4offset:	IPv4 payload offset in the iovec array
  */
-static void tcp_update_check_tcp4(const struct iphdr *iph,
+static void tcp_update_check_tcp4(const struct iphdr *iph, struct tcphdr *th)
-				  const struct iovec *iov, int iov_cnt,
-				  size_t l4offset)
 {
 	uint16_t l4len = ntohs(iph->tot_len) - sizeof(struct iphdr);
 	struct in_addr saddr = { .s_addr = iph->saddr };
 	struct in_addr daddr = { .s_addr = iph->daddr };
-	size_t check_ofs;
+	uint32_t sum = proto_ipv4_header_psum(l4len, IPPROTO_TCP, saddr, daddr);
-	uint16_t *check;
-	int check_idx;
-	uint32_t sum;
-	char *ptr;
 
-	sum = proto_ipv4_header_psum(l4len, IPPROTO_TCP, saddr, daddr);
+	th->check = 0;
-
+	th->check = csum(th, l4len, sum);
-	check_idx = iov_skip_bytes(iov, iov_cnt,
-				   l4offset + offsetof(struct tcphdr, check),
-				   &check_ofs);
-
-	if (check_idx >= iov_cnt) {
-		err("TCP4 buffer is too small, iov size %zd, check offset %zd",
-		    iov_size(iov, iov_cnt),
-		    l4offset + offsetof(struct tcphdr, check));
-		return;
-	}
-
-	if (check_ofs + sizeof(*check) > iov[check_idx].iov_len) {
-		err("TCP4 checksum field memory is not contiguous "
-		    "check_ofs %zd check_idx %d iov_len %zd",
-		    check_ofs, check_idx, iov[check_idx].iov_len);
-		return;
-	}
-
-	ptr = (char *)iov[check_idx].iov_base + check_ofs;
-	if ((uintptr_t)ptr & (__alignof__(*check) - 1)) {
-		err("TCP4 checksum field is not correctly aligned in memory");
-		return;
-	}
-
-	check = (uint16_t *)ptr;
-
-	*check = 0;
-	*check = csum_iov(iov, iov_cnt, l4offset, sum);
 }
 
 /**
  * tcp_update_check_tcp6() - Calculate TCP checksum for IPv6
  * @ip6h:	IPv6 header
- * @iov:	Pointer to the array of IO vectors
+ * @th:		TCP header followed by TCP payload
- * @iov_cnt:	Length of the array
- * @l4offset:	IPv6 payload offset in the iovec array
  */
-static void tcp_update_check_tcp6(const struct ipv6hdr *ip6h,
+static void tcp_update_check_tcp6(struct ipv6hdr *ip6h, struct tcphdr *th)
-				  const struct iovec *iov, int iov_cnt,
-				  size_t l4offset)
 {
 	uint16_t l4len = ntohs(ip6h->payload_len);
-	size_t check_ofs;
+	uint32_t sum = proto_ipv6_header_psum(l4len, IPPROTO_TCP,
-	uint16_t *check;
+					      &ip6h->saddr, &ip6h->daddr);
-	int check_idx;
-	uint32_t sum;
-	char *ptr;
 
-	sum = proto_ipv6_header_psum(l4len, IPPROTO_TCP, &ip6h->saddr,
+	th->check = 0;
-				     &ip6h->daddr);
+	th->check = csum(th, l4len, sum);
-
-	check_idx = iov_skip_bytes(iov, iov_cnt,
-				   l4offset + offsetof(struct tcphdr, check),
-				   &check_ofs);
-
-	if (check_idx >= iov_cnt) {
-		err("TCP6 buffer is too small, iov size %zd, check offset %zd",
-		    iov_size(iov, iov_cnt),
-		    l4offset + offsetof(struct tcphdr, check));
-		return;
-	}
-
-	if (check_ofs + sizeof(*check) > iov[check_idx].iov_len) {
-		err("TCP6 checksum field memory is not contiguous "
-		    "check_ofs %zd check_idx %d iov_len %zd",
-		    check_ofs, check_idx, iov[check_idx].iov_len);
-		return;
-	}
-
-	ptr = (char *)iov[check_idx].iov_base + check_ofs;
-	if ((uintptr_t)ptr & (__alignof__(*check) - 1)) {
-		err("TCP6 checksum field is not correctly aligned in memory");
-		return;
-	}
-
-	check = (uint16_t *)ptr;
-
-	*check = 0;
-	*check = csum_iov(iov, iov_cnt, l4offset, sum);
 }
 
 /**
@@ -937,6 +869,7 @@ bool tcp_flow_defer(const struct tcp_tap_conn *conn)
 /* cppcheck-suppress [constParameterPointer, unmatchedSuppression] */
 void tcp_defer_handler(struct ctx *c)
 {
+	tcp_flags_flush(c);
 	tcp_payload_flush(c);
 }
 
@@ -967,27 +900,26 @@ static void tcp_fill_header(struct tcphdr *th,
 
 /**
  * tcp_fill_headers4() - Fill 802.3, IPv4, TCP headers in pre-cooked buffers
- * @conn:		Connection pointer
+ * @conn:	Connection pointer
- * @taph:		tap backend specific header
+ * @taph:	tap backend specific header
- * @iph:		Pointer to IPv4 header
+ * @iph:	Pointer to IPv4 header
- * @bp:			Pointer to TCP header followed by TCP payload
+ * @th:		Pointer to TCP header
- * @dlen:		TCP payload length
+ * @dlen:	TCP payload length
- * @check:		Checksum, if already known
+ * @check:	Checksum, if already known
- * @seq:		Sequence number for this segment
+ * @seq:	Sequence number for this segment
- * @no_tcp_csum:	Do not set TCP checksum
  *
  * Return: The IPv4 payload length, host order
  */
 static size_t tcp_fill_headers4(const struct tcp_tap_conn *conn,
 				struct tap_hdr *taph,
-				struct iphdr *iph, struct tcp_payload_t *bp,
+				struct iphdr *iph, struct tcphdr *th,
 				size_t dlen, const uint16_t *check,
-				uint32_t seq, bool no_tcp_csum)
+				uint32_t seq)
 {
 	const struct flowside *tapside = TAPFLOW(conn);
 	const struct in_addr *src4 = inany_v4(&tapside->oaddr);
 	const struct in_addr *dst4 = inany_v4(&tapside->eaddr);
-	size_t l4len = dlen + sizeof(bp->th);
+	size_t l4len = dlen + sizeof(*th);
 	size_t l3len = l4len + sizeof(*iph);
 
 	ASSERT(src4 && dst4);
@@ -999,18 +931,9 @@ static size_t tcp_fill_headers4(const struct tcp_tap_conn *conn,
 	iph->check = check ? *check :
 			     csum_ip4_header(l3len, IPPROTO_TCP, *src4, *dst4);
 
-	tcp_fill_header(&bp->th, conn, seq);
+	tcp_fill_header(th, conn, seq);
 
-	if (no_tcp_csum) {
+	tcp_update_check_tcp4(iph, th);
-		bp->th.check = 0;
-	} else {
-		const struct iovec iov = {
-			.iov_base = bp,
-			.iov_len = ntohs(iph->tot_len) - sizeof(struct iphdr),
-		};
-
-		tcp_update_check_tcp4(iph, &iov, 1, 0);
-	}
 
 	tap_hdr_update(taph, l3len + sizeof(struct ethhdr));
 
@@ -1019,24 +942,23 @@ static size_t tcp_fill_headers4(const struct tcp_tap_conn *conn,
 
 /**
  * tcp_fill_headers6() - Fill 802.3, IPv6, TCP headers in pre-cooked buffers
- * @conn:		Connection pointer
+ * @conn:	Connection pointer
- * @taph:		tap backend specific header
+ * @taph:	tap backend specific header
- * @ip6h:		Pointer to IPv6 header
+ * @ip6h:	Pointer to IPv6 header
- * @bp:			Pointer to TCP header followed by TCP payload
+ * @th:		Pointer to TCP header
- * @dlen:		TCP payload length
+ * @dlen:	TCP payload length
- * @check:		Checksum, if already known
+ * @check:	Checksum, if already known
- * @seq:		Sequence number for this segment
+ * @seq:	Sequence number for this segment
- * @no_tcp_csum:	Do not set TCP checksum
  *
  * Return: The IPv6 payload length, host order
  */
 static size_t tcp_fill_headers6(const struct tcp_tap_conn *conn,
 				struct tap_hdr *taph,
-				struct ipv6hdr *ip6h, struct tcp_payload_t *bp,
+				struct ipv6hdr *ip6h, struct tcphdr *th,
-				size_t dlen, uint32_t seq, bool no_tcp_csum)
+				size_t dlen, uint32_t seq)
 {
 	const struct flowside *tapside = TAPFLOW(conn);
-	size_t l4len = dlen + sizeof(bp->th);
+	size_t l4len = dlen + sizeof(*th);
 
 	ip6h->payload_len = htons(l4len);
 	ip6h->saddr = tapside->oaddr.a6;
@@ -1050,18 +972,9 @@ static size_t tcp_fill_headers6(const struct tcp_tap_conn *conn,
 	ip6h->flow_lbl[1] = (conn->sock >> 8) & 0xff;
 	ip6h->flow_lbl[2] = (conn->sock >> 0) & 0xff;
 
-	tcp_fill_header(&bp->th, conn, seq);
+	tcp_fill_header(th, conn, seq);
 
-	if (no_tcp_csum) {
+	tcp_update_check_tcp6(ip6h, th);
-		bp->th.check = 0;
-	} else {
-		const struct iovec iov = {
-			.iov_base = bp,
-			.iov_len = ntohs(ip6h->payload_len)
-		};
-
-		tcp_update_check_tcp6(ip6h, &iov, 1, 0);
-	}
 
 	tap_hdr_update(taph, l4len + sizeof(*ip6h) + sizeof(struct ethhdr));
 
@@ -1075,14 +988,12 @@ static size_t tcp_fill_headers6(const struct tcp_tap_conn *conn,
  * @dlen:	TCP payload length
  * @check:	Checksum, if already known
  * @seq:	Sequence number for this segment
- * @no_tcp_csum: Do not set TCP checksum
  *
  * Return: IP payload length, host order
  */
 size_t tcp_l2_buf_fill_headers(const struct tcp_tap_conn *conn,
 			       struct iovec *iov, size_t dlen,
-			       const uint16_t *check, uint32_t seq,
+			       const uint16_t *check, uint32_t seq)
-			       bool no_tcp_csum)
 {
 	const struct flowside *tapside = TAPFLOW(conn);
 	const struct in_addr *a4 = inany_v4(&tapside->oaddr);
@@ -1091,13 +1002,13 @@ size_t tcp_l2_buf_fill_headers(const struct tcp_tap_conn *conn,
 		return tcp_fill_headers4(conn, iov[TCP_IOV_TAP].iov_base,
 					 iov[TCP_IOV_IP].iov_base,
 					 iov[TCP_IOV_PAYLOAD].iov_base, dlen,
-					 check, seq, no_tcp_csum);
+					 check, seq);
 	}
 
 	return tcp_fill_headers6(conn, iov[TCP_IOV_TAP].iov_base,
 				 iov[TCP_IOV_IP].iov_base,
 				 iov[TCP_IOV_PAYLOAD].iov_base, dlen,
-				 seq, no_tcp_csum);
+				 seq);
 }
 
 /**
@@ -1110,41 +1021,42 @@ size_t tcp_l2_buf_fill_headers(const struct tcp_tap_conn *conn,
  * Return: 1 if sequence or window were updated, 0 otherwise
  */
 int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn,
-			  bool force_seq, struct tcp_info_linux *tinfo)
+			  int force_seq, struct tcp_info *tinfo)
 {
 	uint32_t prev_wnd_to_tap = conn->wnd_to_tap << conn->ws_to_tap;
 	uint32_t prev_ack_to_tap = conn->seq_ack_to_tap;
 	/* cppcheck-suppress [ctunullpointer, unmatchedSuppression] */
 	socklen_t sl = sizeof(*tinfo);
-	struct tcp_info_linux tinfo_new;
+	struct tcp_info tinfo_new;
 	uint32_t new_wnd_to_tap = prev_wnd_to_tap;
 	int s = conn->sock;
 
-	if (!bytes_acked_cap) {
+#ifndef HAS_BYTES_ACKED
+	(void)force_seq;
+
+	conn->seq_ack_to_tap = conn->seq_from_tap;
+	if (SEQ_LT(conn->seq_ack_to_tap, prev_ack_to_tap))
+		conn->seq_ack_to_tap = prev_ack_to_tap;
+#else
+	if ((unsigned)SNDBUF_GET(conn) < SNDBUF_SMALL || tcp_rtt_dst_low(conn)
+	    || CONN_IS_CLOSING(conn) || (conn->flags & LOCAL) || force_seq) {
 		conn->seq_ack_to_tap = conn->seq_from_tap;
+	} else if (conn->seq_ack_to_tap != conn->seq_from_tap) {
+		if (!tinfo) {
+			tinfo = &tinfo_new;
+			if (getsockopt(s, SOL_TCP, TCP_INFO, tinfo, &sl))
+				return 0;
+		}
+
+		conn->seq_ack_to_tap = tinfo->tcpi_bytes_acked +
+				       conn->seq_init_from_tap;
+
 		if (SEQ_LT(conn->seq_ack_to_tap, prev_ack_to_tap))
 			conn->seq_ack_to_tap = prev_ack_to_tap;
-	} else {
-		if ((unsigned)SNDBUF_GET(conn) < SNDBUF_SMALL ||
-		    tcp_rtt_dst_low(conn) || CONN_IS_CLOSING(conn) ||
-		    (conn->flags & LOCAL) || force_seq) {
-			conn->seq_ack_to_tap = conn->seq_from_tap;
-		} else if (conn->seq_ack_to_tap != conn->seq_from_tap) {
-			if (!tinfo) {
-				tinfo = &tinfo_new;
-				if (getsockopt(s, SOL_TCP, TCP_INFO, tinfo, &sl))
-					return 0;
-			}
-
-			conn->seq_ack_to_tap = tinfo->tcpi_bytes_acked +
-				conn->seq_init_from_tap;
-
-			if (SEQ_LT(conn->seq_ack_to_tap, prev_ack_to_tap))
-				conn->seq_ack_to_tap = prev_ack_to_tap;
-		}
 	}
+#endif /* !HAS_BYTES_ACKED */
 
-	if (!snd_wnd_cap) {
+	if (!KERNEL_REPORTS_SND_WND(c)) {
 		tcp_get_sndbuf(conn);
 		new_wnd_to_tap = MIN(SNDBUF_GET(conn), MAX_WINDOW);
 		conn->wnd_to_tap = MIN(new_wnd_to_tap >> conn->ws_to_tap,
@@ -1155,13 +1067,14 @@ int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn,
 	if (!tinfo) {
 		if (prev_wnd_to_tap > WINDOW_DEFAULT) {
 			goto out;
-		}
+}
 		tinfo = &tinfo_new;
 		if (getsockopt(s, SOL_TCP, TCP_INFO, tinfo, &sl)) {
 			goto out;
-		}
+}
 	}
 
+#ifdef HAS_SND_WND
 	if ((conn->flags & LOCAL) || tcp_rtt_dst_low(conn)) {
 		new_wnd_to_tap = tinfo->tcpi_snd_wnd;
 	} else {
@@ -1169,6 +1082,7 @@ int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn,
 		new_wnd_to_tap = MIN((int)tinfo->tcpi_snd_wnd,
 				     SNDBUF_GET(conn));
 	}
+#endif
 
 	new_wnd_to_tap = MIN(new_wnd_to_tap, MAX_WINDOW);
 	if (!(conn->events & ESTABLISHED))
@@ -1226,11 +1140,11 @@ static void tcp_update_seqack_from_tap(const struct ctx *c,
  *	     0 if there is no flag to send
  *	     1 otherwise
  */
-int tcp_prepare_flags(const struct ctx *c, struct tcp_tap_conn *conn,
+int tcp_prepare_flags(struct ctx *c, struct tcp_tap_conn *conn,
-		      int flags, struct tcphdr *th, struct tcp_syn_opts *opts,
+		      int flags, struct tcphdr *th, char *data,
 		      size_t *optlen)
 {
-	struct tcp_info_linux tinfo = { 0 };
+	struct tcp_info tinfo = { 0 };
 	socklen_t sl = sizeof(tinfo);
 	int s = conn->sock;
 
@@ -1243,16 +1157,27 @@ int tcp_prepare_flags(const struct ctx *c, struct tcp_tap_conn *conn,
 		return -ECONNRESET;
 	}
 
+#ifdef HAS_SND_WND
+	if (!c->tcp.kernel_snd_wnd && tinfo.tcpi_snd_wnd)
+		c->tcp.kernel_snd_wnd = 1;
+#endif
+
 	if (!(conn->flags & LOCAL))
 		tcp_rtt_dst_check(conn, &tinfo);
 
-	if (!tcp_update_seqack_wnd(c, conn, !!flags, &tinfo) && !flags)
+	if (!tcp_update_seqack_wnd(c, conn, flags, &tinfo) && !flags)
 		return 0;
 
 	*optlen = 0;
 	if (flags & SYN) {
 		int mss;
 
+		/* Options: MSS, NOP and window scale (8 bytes) */
+		*optlen = OPT_MSS_LEN + 1 + OPT_WS_LEN;
+
+		*data++ = OPT_MSS;
+		*data++ = OPT_MSS_LEN;
+
 		if (c->mtu == -1) {
 			mss = tinfo.tcpi_snd_mss;
 		} else {
@@ -1268,11 +1193,16 @@ int tcp_prepare_flags(const struct ctx *c, struct tcp_tap_conn *conn,
 			else if (mss > PAGE_SIZE)
 				mss = ROUND_DOWN(mss, PAGE_SIZE);
 		}
+		*(uint16_t *)data = htons(MIN(USHRT_MAX, mss));
+
+		data += OPT_MSS_LEN - 2;
 
 		conn->ws_to_tap = MIN(MAX_WS, tinfo.tcpi_snd_wscale);
 
-		*opts = TCP_SYN_OPTS(mss, conn->ws_to_tap);
+		*data++ = OPT_NOP;
-		*optlen = sizeof(*opts);
+		*data++ = OPT_WS;
+		*data++ = OPT_WS_LEN;
+		*data++ = conn->ws_to_tap;
 	} else if (!(flags & RST)) {
 		flags |= ACK;
 	}
@@ -1309,8 +1239,7 @@ int tcp_prepare_flags(const struct ctx *c, struct tcp_tap_conn *conn,
  *
  * Return: negative error code on connection reset, 0 otherwise
  */
-static int tcp_send_flag(const struct ctx *c, struct tcp_tap_conn *conn,
+int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags)
-			 int flags)
 {
 	return tcp_buf_send_flag(c, conn, flags);
 }
@@ -1320,7 +1249,7 @@ static int tcp_send_flag(const struct ctx *c, struct tcp_tap_conn *conn,
  * @c:		Execution context
  * @conn:	Connection pointer
  */
-void tcp_rst_do(const struct ctx *c, struct tcp_tap_conn *conn)
+void tcp_rst_do(struct ctx *c, struct tcp_tap_conn *conn)
 {
 	if (conn->events == CLOSED)
 		return;
@@ -1410,7 +1339,7 @@ static int tcp_conn_new_sock(const struct ctx *c, sa_family_t af)
 {
 	int s;
 
-	s = socket(af, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, IPPROTO_TCP);
+	s = socket(af, SOCK_STREAM | SOCK_NONBLOCK, IPPROTO_TCP);
 
 	if (s > FD_REF_MAX) {
 		close(s);
@@ -1538,7 +1467,7 @@ static void tcp_bind_outbound(const struct ctx *c,
  * @optlen:	Bytes in options: caller MUST ensure available length
  * @now:	Current timestamp
  */
-static void tcp_conn_from_tap(const struct ctx *c, sa_family_t af,
+static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
 			      const void *saddr, const void *daddr,
 			      const struct tcphdr *th, const char *opts,
 			      size_t optlen, const struct timespec *now)
@@ -1703,7 +1632,7 @@ static int tcp_sock_consume(const struct tcp_tap_conn *conn, uint32_t ack_seq)
  *
  * #syscalls recvmsg
  */
-static int tcp_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn)
+static int tcp_data_from_sock(struct ctx *c, struct tcp_tap_conn *conn)
 {
 	return tcp_buf_data_from_sock(c, conn);
 }
@@ -1719,8 +1648,8 @@ static int tcp_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn)
  *
  * Return: count of consumed packets
  */
-static int tcp_data_from_tap(const struct ctx *c, struct tcp_tap_conn *conn,
+static int tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
-			     const struct pool *p, int idx)
+			      const struct pool *p, int idx)
 {
 	int i, iov_i, ack = 0, fin = 0, retr = 0, keep = -1, partial_send = 0;
 	uint16_t max_ack_seq_wnd = conn->wnd_from_tap;
@@ -1917,8 +1846,7 @@ out:
  * @opts:	Pointer to start of options
  * @optlen:	Bytes in options: caller MUST ensure available length
  */
-static void tcp_conn_from_sock_finish(const struct ctx *c,
+static void tcp_conn_from_sock_finish(struct ctx *c, struct tcp_tap_conn *conn,
-				      struct tcp_tap_conn *conn,
 				      const struct tcphdr *th,
 				      const char *opts, size_t optlen)
 {
@@ -1941,12 +1869,11 @@ static void tcp_conn_from_sock_finish(const struct ctx *c,
 		return;
 	}
 
-	tcp_send_flag(c, conn, ACK);
-
 	/* The client might have sent data already, which we didn't
 	 * dequeue waiting for SYN,ACK from tap -- check now.
 	 */
 	tcp_data_from_sock(c, conn);
+	tcp_send_flag(c, conn, ACK);
 }
 
 /**
@@ -1962,7 +1889,7 @@ static void tcp_conn_from_sock_finish(const struct ctx *c,
  *
  * Return: count of consumed packets
  */
-int tcp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
+int tcp_tap_handler(struct ctx *c, uint8_t pif, sa_family_t af,
 		    const void *saddr, const void *daddr,
 		    const struct pool *p, int idx, const struct timespec *now)
 {
@@ -2100,7 +2027,7 @@ reset:
  * @c:		Execution context
  * @conn:	Connection pointer
  */
-static void tcp_connect_finish(const struct ctx *c, struct tcp_tap_conn *conn)
+static void tcp_connect_finish(struct ctx *c, struct tcp_tap_conn *conn)
 {
 	socklen_t sl;
 	int so;
@@ -2126,8 +2053,8 @@ static void tcp_connect_finish(const struct ctx *c, struct tcp_tap_conn *conn)
  * @sa:		Peer socket address (from accept())
  * @now:	Current timestamp
  */
-static void tcp_tap_conn_from_sock(const struct ctx *c, union flow *flow,
+static void tcp_tap_conn_from_sock(struct ctx *c, union flow *flow, int s,
-				   int s, const struct timespec *now)
+				   const struct timespec *now)
 {
 	struct tcp_tap_conn *conn = FLOW_SET_TYPE(flow, FLOW_TCP, tcp);
 	uint64_t hash;
@@ -2158,7 +2085,7 @@ static void tcp_tap_conn_from_sock(const struct ctx *c, union flow *flow,
  * @ref:	epoll reference of listening socket
  * @now:	Current timestamp
  */
-void tcp_listen_handler(const struct ctx *c, union epoll_ref ref,
+void tcp_listen_handler(struct ctx *c, union epoll_ref ref,
 			const struct timespec *now)
 {
 	const struct flowside *ini;
@@ -2223,7 +2150,7 @@ cancel:
  *
  * #syscalls timerfd_gettime arm:timerfd_gettime64 i686:timerfd_gettime64
  */
-void tcp_timer_handler(const struct ctx *c, union epoll_ref ref)
+void tcp_timer_handler(struct ctx *c, union epoll_ref ref)
 {
 	struct itimerspec check_armed = { { 0 }, { 0 } };
 	struct tcp_tap_conn *conn = &FLOW(ref.flow)->tcp;
@@ -2235,9 +2162,7 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref)
 	 * timer is currently armed, this event came from a previous setting,
 	 * and we just set the timer to a new point in the future: discard it.
 	 */
-	if (timerfd_gettime(conn->timer, &check_armed))
+	timerfd_gettime(conn->timer, &check_armed);
-		flow_err(conn, "failed to read timer: %s", strerror(errno));
-
 	if (check_armed.it_value.tv_sec || check_armed.it_value.tv_nsec)
 		return;
 
@@ -2275,10 +2200,7 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref)
 		 * case. This avoids having to preemptively reset the timer on
 		 * ~ACK_TO_TAP_DUE or ~ACK_FROM_TAP_DUE.
 		 */
-		if (timerfd_settime(conn->timer, 0, &new, &old))
+		timerfd_settime(conn->timer, 0, &new, &old);
-			flow_err(conn, "failed to set timer: %s",
-				 strerror(errno));
-
 		if (old.it_value.tv_sec == ACT_TIMEOUT) {
 			flow_dbg(conn, "activity timeout");
 			tcp_rst(c, conn);
@@ -2292,14 +2214,19 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref)
  * @ref:	epoll reference
  * @events:	epoll events bitmap
  */
-void tcp_sock_handler(const struct ctx *c, union epoll_ref ref,
+void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events)
-		      uint32_t events)
 {
 	struct tcp_tap_conn *conn = conn_at_sidx(ref.flowside);
 
 	ASSERT(!c->no_tcp);
 	ASSERT(pif_at_sidx(ref.flowside) != PIF_TAP);
 
+	if (events & EPOLLRDHUP) {
+		flow_err(conn, "EPOLLRDHUP: events=0x%x  conn->events=0x%x "
+			 "conn->flags=0x%x\n", events, conn->events,
+			 conn->flags);
+	}
+
 	if (conn->events == CLOSED)
 		return;
 
@@ -2324,7 +2251,7 @@ void tcp_sock_handler(const struct ctx *c, union epoll_ref ref,
 			tcp_data_from_sock(c, conn);
 
 		if (events & EPOLLOUT)
-			tcp_update_seqack_wnd(c, conn, false, NULL);
+			tcp_update_seqack_wnd(c, conn, 0, NULL);
 
 		return;
 	}
@@ -2347,16 +2274,17 @@ void tcp_sock_handler(const struct ctx *c, union epoll_ref ref,
 }
 
 /**
- * tcp_sock_init_one() - Initialise listening socket for address and port
+ * tcp_sock_init_af() - Initialise listening socket for a given af and port
  * @c:		Execution context
- * @addr:	Pointer to address for binding, NULL for dual stack any
+ * @af:		Address family to listen on
- * @ifname:	Name of interface to bind to, NULL if not configured
  * @port:	Port, host order
+ * @addr:	Pointer to address for binding, NULL if not configured
+ * @ifname:	Name of interface to bind to, NULL if not configured
  *
  * Return: fd for the new listening socket, negative error code on failure
  */
-static int tcp_sock_init_one(const struct ctx *c, const union inany_addr *addr,
+static int tcp_sock_init_af(const struct ctx *c, sa_family_t af, in_port_t port,
-			     const char *ifname, in_port_t port)
+			    const void *addr, const char *ifname)
 {
 	union tcp_listen_epoll_ref tref = {
 		.port = port,
@@ -2364,13 +2292,12 @@ static int tcp_sock_init_one(const struct ctx *c, const union inany_addr *addr,
 	};
 	int s;
 
-	s = pif_sock_l4(c, EPOLL_TYPE_TCP_LISTEN, PIF_HOST, addr,
+	s = sock_l4(c, af, EPOLL_TYPE_TCP_LISTEN, addr, ifname, port, tref.u32);
-				ifname, port, tref.u32);
 
 	if (c->tcp.fwd_in.mode == FWD_AUTO) {
-		if (!addr || inany_v4(addr))
+		if (af == AF_INET  || af == AF_UNSPEC)
 			tcp_sock_init_ext[port][V4] = s < 0 ? -1 : s;
-		if (!addr || !inany_v4(addr))
+		if (af == AF_INET6 || af == AF_UNSPEC)
 			tcp_sock_init_ext[port][V6] = s < 0 ? -1 : s;
 	}
 
@@ -2384,32 +2311,31 @@ static int tcp_sock_init_one(const struct ctx *c, const union inany_addr *addr,
 /**
  * tcp_sock_init() - Create listening sockets for a given host ("inbound") port
  * @c:		Execution context
+ * @af:		Address family to select a specific IP version, or AF_UNSPEC
  * @addr:	Pointer to address for binding, NULL if not configured
  * @ifname:	Name of interface to bind to, NULL if not configured
  * @port:	Port, host order
  *
  * Return: 0 on (partial) success, negative error code on (complete) failure
  */
-int tcp_sock_init(const struct ctx *c, const union inany_addr *addr,
+int tcp_sock_init(const struct ctx *c, sa_family_t af, const void *addr,
 		  const char *ifname, in_port_t port)
 {
 	int r4 = FD_REF_MAX + 1, r6 = FD_REF_MAX + 1;
 
 	ASSERT(!c->no_tcp);
 
-	if (!addr && c->ifi4 && c->ifi6)
+	if (af == AF_UNSPEC && c->ifi4 && c->ifi6)
 		/* Attempt to get a dual stack socket */
-		if (tcp_sock_init_one(c, NULL, ifname, port) >= 0)
+		if (tcp_sock_init_af(c, AF_UNSPEC, port, addr, ifname) >= 0)
 			return 0;
 
 	/* Otherwise create a socket per IP version */
-	if ((!addr || inany_v4(addr)) && c->ifi4)
+	if ((af == AF_INET  || af == AF_UNSPEC) && c->ifi4)
-		r4 = tcp_sock_init_one(c, addr ? addr : &inany_any4,
+		r4 = tcp_sock_init_af(c, AF_INET, port, addr, ifname);
-				       ifname, port);
 
-	if ((!addr || !inany_v4(addr)) && c->ifi6)
+	if ((af == AF_INET6 || af == AF_UNSPEC) && c->ifi6)
-		r6 = tcp_sock_init_one(c, addr ? addr : &inany_any6,
+		r6 = tcp_sock_init_af(c, AF_INET6, port, addr, ifname);
-				       ifname, port);
 
 	if (IN_INTERVAL(0, FD_REF_MAX, r4) || IN_INTERVAL(0, FD_REF_MAX, r6))
 		return 0;
@@ -2432,8 +2358,8 @@ static void tcp_ns_sock_init4(const struct ctx *c, in_port_t port)
 
 	ASSERT(c->mode == MODE_PASTA);
 
-	s = pif_sock_l4(c, EPOLL_TYPE_TCP_LISTEN, PIF_SPLICE, &inany_loopback4,
+	s = sock_l4(c, AF_INET, EPOLL_TYPE_TCP_LISTEN, &in4addr_loopback,
-			NULL, port, tref.u32);
+		    NULL, port, tref.u32);
 	if (s >= 0)
 		tcp_sock_set_bufsize(c, s);
 	else
@@ -2458,8 +2384,8 @@ static void tcp_ns_sock_init6(const struct ctx *c, in_port_t port)
 
 	ASSERT(c->mode == MODE_PASTA);
 
-	s = pif_sock_l4(c, EPOLL_TYPE_TCP_LISTEN, PIF_SPLICE, &inany_loopback6,
+	s = sock_l4(c, AF_INET6, EPOLL_TYPE_TCP_LISTEN, &in6addr_loopback,
-			NULL, port, tref.u32);
+		    NULL, port, tref.u32);
 	if (s >= 0)
 		tcp_sock_set_bufsize(c, s);
 	else
@@ -2561,7 +2487,7 @@ static void tcp_sock_refill_init(const struct ctx *c)
  *
  * Return: true if supported, false otherwise
  */
-static bool tcp_probe_peek_offset_cap(sa_family_t af)
+bool tcp_probe_peek_offset_cap(sa_family_t af)
 {
 	bool ret = false;
 	int s, optv = 0;
@@ -2578,34 +2504,6 @@ static bool tcp_probe_peek_offset_cap(sa_family_t af)
 	return ret;
 }
 
-/**
- * tcp_probe_tcp_info() - Check what data TCP_INFO reports
- *
- * Return: Number of bytes returned by TCP_INFO getsockopt()
- */
-static socklen_t tcp_probe_tcp_info(void)
-{
-	struct tcp_info_linux tinfo;
-	socklen_t sl = sizeof(tinfo);
-	int s;
-
-	s = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);
-	if (s < 0) {
-		warn_perror("Temporary TCP socket creation failed");
-		return false;
-	}
-
-	if (getsockopt(s, SOL_TCP, TCP_INFO, &tinfo, &sl)) {
-		warn_perror("Failed to get TCP_INFO on temporary socket");
-		close(s);
-		return false;
-	}
-
-	close(s);
-
-	return sl;
-}
-
 /**
  * tcp_init() - Get initial sequence, hash secret, initialise per-socket data
  * @c:		Execution context
@@ -2616,7 +2514,11 @@ int tcp_init(struct ctx *c)
 {
 	ASSERT(!c->no_tcp);
 
-	tcp_sock_iov_init(c);
+	if (c->ifi4)
+		tcp_sock4_iov_init(c);
+
+	if (c->ifi6)
+		tcp_sock6_iov_init(c);
 
 	memset(init_sock_pool4,		0xff,	sizeof(init_sock_pool4));
 	memset(init_sock_pool6,		0xff,	sizeof(init_sock_pool6));
@@ -2635,15 +2537,6 @@ int tcp_init(struct ctx *c)
 			  (!c->ifi6 || tcp_probe_peek_offset_cap(AF_INET6));
 	debug("SO_PEEK_OFF%ssupported", peek_offset_cap ? " " : " not ");
 
-	tcp_info_size = tcp_probe_tcp_info();
-
-#define dbg_tcpi(f_)	debug("TCP_INFO tcpi_%s field%s supported",	\
-			      STRINGIFY(f_), tcp_info_cap(f_) ? " " : " not ")
-	dbg_tcpi(snd_wnd);
-	dbg_tcpi(bytes_acked);
-	dbg_tcpi(min_rtt);
-#undef dbg_tcpi
-
 	return 0;
 }
 
@@ -2685,7 +2578,7 @@ static void tcp_port_rebind(struct ctx *c, bool outbound)
 			if (outbound)
 				tcp_ns_sock_init(c, port);
 			else
-				tcp_sock_init(c, NULL, NULL, port);
+				tcp_sock_init(c, AF_UNSPEC, NULL, NULL, port);
 		}
 	}
 }

tcp.h

@@ -10,15 +10,14 @@
 
 struct ctx;
 
-void tcp_timer_handler(const struct ctx *c, union epoll_ref ref);
+void tcp_timer_handler(struct ctx *c, union epoll_ref ref);
-void tcp_listen_handler(const struct ctx *c, union epoll_ref ref,
+void tcp_listen_handler(struct ctx *c, union epoll_ref ref,
 			const struct timespec *now);
-void tcp_sock_handler(const struct ctx *c, union epoll_ref ref,
+void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events);
-		      uint32_t events);
+int tcp_tap_handler(struct ctx *c, uint8_t pif, sa_family_t af,
-int tcp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
 		    const void *saddr, const void *daddr,
 		    const struct pool *p, int idx, const struct timespec *now);
-int tcp_sock_init(const struct ctx *c, const union inany_addr *addr,
+int tcp_sock_init(const struct ctx *c, sa_family_t af, const void *addr,
 		  const char *ifname, in_port_t port);
 int tcp_init(struct ctx *c);
 void tcp_timer(struct ctx *c, const struct timespec *now);
@@ -59,12 +58,16 @@ union tcp_listen_epoll_ref {
  * @fwd_in:		Port forwarding configuration for inbound packets
  * @fwd_out:		Port forwarding configuration for outbound packets
  * @timer_run:		Timestamp of most recent timer run
+ * @kernel_snd_wnd:	Kernel reports sending window (with commit 8f7baad7f035)
  * @pipe_size:		Size of pipes for spliced connections
  */
 struct tcp_ctx {
 	struct fwd_ports fwd_in;
 	struct fwd_ports fwd_out;
 	struct timespec timer_run;
+#ifdef HAS_SND_WND
+	int kernel_snd_wnd;
+#endif
 	size_t pipe_size;
 };
 

tcp_buf.c

@@ -20,7 +20,7 @@
 
 #include <netinet/ip.h>
 
-#include <netinet/tcp.h>
+#include <linux/tcp.h>
 
 #include "util.h"
 #include "ip.h"
@@ -38,32 +38,88 @@
 	(c->mode == MODE_PASTA ? 1 : TCP_FRAMES_MEM)
 
 /* Static buffers */
+/**
+ * struct tcp_payload_t - TCP header and data to send segments with payload
+ * @th:		TCP header
+ * @data:	TCP data
+ */
+struct tcp_payload_t {
+	struct tcphdr th;
+	uint8_t data[IP_MAX_MTU - sizeof(struct tcphdr)];
+#ifdef __AVX2__
+} __attribute__ ((packed, aligned(32)));    /* For AVX2 checksum routines */
+#else
+} __attribute__ ((packed, aligned(__alignof__(unsigned int))));
+#endif
 
-/* Ethernet header for IPv4 and IPv6 frames */
+/**
+ * struct tcp_flags_t - TCP header and data to send zero-length
+ *                      segments (flags)
+ * @th:		TCP header
+ * @opts	TCP options
+ */
+struct tcp_flags_t {
+	struct tcphdr th;
+	char opts[OPT_MSS_LEN + OPT_WS_LEN + 1];
+#ifdef __AVX2__
+} __attribute__ ((packed, aligned(32)));
+#else
+} __attribute__ ((packed, aligned(__alignof__(unsigned int))));
+#endif
+
+/* Ethernet header for IPv4 frames */
 static struct ethhdr		tcp4_eth_src;
-static struct ethhdr		tcp6_eth_src;
 
-static struct tap_hdr		tcp_payload_tap_hdr[TCP_FRAMES_MEM];
+static struct tap_hdr		tcp4_payload_tap_hdr[TCP_FRAMES_MEM];
+/* IPv4 headers */
+static struct iphdr		tcp4_payload_ip[TCP_FRAMES_MEM];
+/* TCP segments with payload for IPv4 frames */
+static struct tcp_payload_t	tcp4_payload[TCP_FRAMES_MEM];
 
-/* IP headers for IPv4 and IPv6 */
+static_assert(MSS4 <= sizeof(tcp4_payload[0].data), "MSS4 is greater than 65516");
-struct iphdr		tcp4_payload_ip[TCP_FRAMES_MEM];
-struct ipv6hdr		tcp6_payload_ip[TCP_FRAMES_MEM];
-
-/* TCP segments with payload for IPv4 and IPv6 frames */
-static struct tcp_payload_t	tcp_payload[TCP_FRAMES_MEM];
-
-static_assert(MSS4 <= sizeof(tcp_payload[0].data), "MSS4 is greater than 65516");
-static_assert(MSS6 <= sizeof(tcp_payload[0].data), "MSS6 is greater than 65516");
 
 /* References tracking the owner connection of frames in the tap outqueue */
-static struct tcp_tap_conn *tcp_frame_conns[TCP_FRAMES_MEM];
+static struct tcp_tap_conn *tcp4_frame_conns[TCP_FRAMES_MEM];
-static unsigned int tcp_payload_used;
+static unsigned int tcp4_payload_used;
+
+static struct tap_hdr		tcp4_flags_tap_hdr[TCP_FRAMES_MEM];
+/* IPv4 headers for TCP segment without payload */
+static struct iphdr		tcp4_flags_ip[TCP_FRAMES_MEM];
+/* TCP segments without payload for IPv4 frames */
+static struct tcp_flags_t	tcp4_flags[TCP_FRAMES_MEM];
+
+static unsigned int tcp4_flags_used;
+
+/* Ethernet header for IPv6 frames */
+static struct ethhdr		tcp6_eth_src;
+
+static struct tap_hdr		tcp6_payload_tap_hdr[TCP_FRAMES_MEM];
+/* IPv6 headers */
+static struct ipv6hdr		tcp6_payload_ip[TCP_FRAMES_MEM];
+/* TCP headers and data for IPv6 frames */
+static struct tcp_payload_t	tcp6_payload[TCP_FRAMES_MEM];
+
+static_assert(MSS6 <= sizeof(tcp6_payload[0].data), "MSS6 is greater than 65516");
+
+/* References tracking the owner connection of frames in the tap outqueue */
+static struct tcp_tap_conn *tcp6_frame_conns[TCP_FRAMES_MEM];
+static unsigned int tcp6_payload_used;
+
+static struct tap_hdr		tcp6_flags_tap_hdr[TCP_FRAMES_MEM];
+/* IPv6 headers for TCP segment without payload */
+static struct ipv6hdr		tcp6_flags_ip[TCP_FRAMES_MEM];
+/* TCP segment without payload for IPv6 frames */
+static struct tcp_flags_t	tcp6_flags[TCP_FRAMES_MEM];
+
+static unsigned int tcp6_flags_used;
 
 /* recvmsg()/sendmsg() data for tap */
 static struct iovec	iov_sock		[TCP_FRAMES_MEM + 1];
 
-static struct iovec	tcp_l2_iov[TCP_FRAMES_MEM][TCP_NUM_IOVS];
+static struct iovec	tcp4_l2_iov		[TCP_FRAMES_MEM][TCP_NUM_IOVS];
-
+static struct iovec	tcp6_l2_iov		[TCP_FRAMES_MEM][TCP_NUM_IOVS];
+static struct iovec	tcp4_l2_flags_iov	[TCP_FRAMES_MEM][TCP_NUM_IOVS];
+static struct iovec	tcp6_l2_flags_iov	[TCP_FRAMES_MEM][TCP_NUM_IOVS];
 /**
  * tcp_update_l2_buf() - Update Ethernet header buffers with addresses
  * @eth_d:	Ethernet destination address, NULL if unchanged
@@ -76,30 +132,105 @@ void tcp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s)
 }
 
 /**
- * tcp_sock_iov_init() - Initialise scatter-gather L2 buffers for IPv4 sockets
+ * tcp_sock4_iov_init() - Initialise scatter-gather L2 buffers for IPv4 sockets
  * @c:		Execution context
  */
-void tcp_sock_iov_init(const struct ctx *c)
+void tcp_sock4_iov_init(const struct ctx *c)
 {
-	struct ipv6hdr ip6 = L2_BUF_IP6_INIT(IPPROTO_TCP);
 	struct iphdr iph = L2_BUF_IP4_INIT(IPPROTO_TCP);
+	struct iovec *iov;
 	int i;
 
-	tcp6_eth_src.h_proto = htons_constant(ETH_P_IPV6);
 	tcp4_eth_src.h_proto = htons_constant(ETH_P_IP);
 
-	for (i = 0; i < ARRAY_SIZE(tcp_payload); i++) {
+	for (i = 0; i < ARRAY_SIZE(tcp4_payload); i++) {
-		tcp6_payload_ip[i] = ip6;
 		tcp4_payload_ip[i] = iph;
+		tcp4_payload[i].th.doff = sizeof(struct tcphdr) / 4;
+		tcp4_payload[i].th.ack = 1;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(tcp4_flags); i++) {
+		tcp4_flags_ip[i] = iph;
+		tcp4_flags[i].th.doff = sizeof(struct tcphdr) / 4;
+		tcp4_flags[i].th.ack = 1;
 	}
 
 	for (i = 0; i < TCP_FRAMES_MEM; i++) {
-		struct iovec *iov = tcp_l2_iov[i];
+		iov = tcp4_l2_iov[i];
 
-		iov[TCP_IOV_TAP] = tap_hdr_iov(c, &tcp_payload_tap_hdr[i]);
+		iov[TCP_IOV_TAP] = tap_hdr_iov(c, &tcp4_payload_tap_hdr[i]);
-		iov[TCP_IOV_ETH].iov_len = sizeof(struct ethhdr);
+		iov[TCP_IOV_ETH] = IOV_OF_LVALUE(tcp4_eth_src);
-		iov[TCP_IOV_PAYLOAD].iov_base = &tcp_payload[i];
+		iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp4_payload_ip[i]);
+		iov[TCP_IOV_PAYLOAD].iov_base = &tcp4_payload[i];
 	}
+
+	for (i = 0; i < TCP_FRAMES_MEM; i++) {
+		iov = tcp4_l2_flags_iov[i];
+
+		iov[TCP_IOV_TAP] = tap_hdr_iov(c, &tcp4_flags_tap_hdr[i]);
+		iov[TCP_IOV_ETH].iov_base = &tcp4_eth_src;
+		iov[TCP_IOV_ETH] = IOV_OF_LVALUE(tcp4_eth_src);
+		iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp4_flags_ip[i]);
+		iov[TCP_IOV_PAYLOAD].iov_base = &tcp4_flags[i];
+	}
+}
+
+/**
+ * tcp_sock6_iov_init() - Initialise scatter-gather L2 buffers for IPv6 sockets
+ * @c:		Execution context
+ */
+void tcp_sock6_iov_init(const struct ctx *c)
+{
+	struct ipv6hdr ip6 = L2_BUF_IP6_INIT(IPPROTO_TCP);
+	struct iovec *iov;
+	int i;
+
+	tcp6_eth_src.h_proto = htons_constant(ETH_P_IPV6);
+
+	for (i = 0; i < ARRAY_SIZE(tcp6_payload); i++) {
+		tcp6_payload_ip[i] = ip6;
+		tcp6_payload[i].th.doff = sizeof(struct tcphdr) / 4;
+		tcp6_payload[i].th.ack = 1;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(tcp6_flags); i++) {
+		tcp6_flags_ip[i] = ip6;
+		tcp6_flags[i].th.doff = sizeof(struct tcphdr) / 4;
+		tcp6_flags[i].th .ack = 1;
+	}
+
+	for (i = 0; i < TCP_FRAMES_MEM; i++) {
+		iov = tcp6_l2_iov[i];
+
+		iov[TCP_IOV_TAP] = tap_hdr_iov(c, &tcp6_payload_tap_hdr[i]);
+		iov[TCP_IOV_ETH] = IOV_OF_LVALUE(tcp6_eth_src);
+		iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp6_payload_ip[i]);
+		iov[TCP_IOV_PAYLOAD].iov_base = &tcp6_payload[i];
+	}
+
+	for (i = 0; i < TCP_FRAMES_MEM; i++) {
+		iov = tcp6_l2_flags_iov[i];
+
+		iov[TCP_IOV_TAP] = tap_hdr_iov(c, &tcp6_flags_tap_hdr[i]);
+		iov[TCP_IOV_ETH] = IOV_OF_LVALUE(tcp6_eth_src);
+		iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp6_flags_ip[i]);
+		iov[TCP_IOV_PAYLOAD].iov_base = &tcp6_flags[i];
+	}
+}
+
+/**
+ * tcp_flags_flush() - Send out buffers for segments with no data (flags)
+ * @c:		Execution context
+ */
+void tcp_flags_flush(const struct ctx *c)
+{
+	tap_send_frames(c, &tcp6_l2_flags_iov[0][0], TCP_NUM_IOVS,
+			tcp6_flags_used);
+	tcp6_flags_used = 0;
+
+	tap_send_frames(c, &tcp4_l2_flags_iov[0][0], TCP_NUM_IOVS,
+			tcp4_flags_used);
+	tcp4_flags_used = 0;
 }
 
 /**
@@ -109,7 +240,7 @@ void tcp_sock_iov_init(const struct ctx *c)
  * @frames:	Two-dimensional array containing queued frames with sub-iovs
  * @num_frames:	Number of entries in the two arrays to be compared
  */
-static void tcp_revert_seq(const struct ctx *c, struct tcp_tap_conn **conns,
+static void tcp_revert_seq(struct ctx *c, struct tcp_tap_conn **conns,
 			   struct iovec (*frames)[TCP_NUM_IOVS], int num_frames)
 {
 	int i;
@@ -131,20 +262,28 @@ static void tcp_revert_seq(const struct ctx *c, struct tcp_tap_conn **conns,
 }
 
 /**
- * tcp_payload_flush() - Send out buffers for segments with data or flags
+ * tcp_payload_flush() - Send out buffers for segments with data
  * @c:		Execution context
  */
-void tcp_payload_flush(const struct ctx *c)
+void tcp_payload_flush(struct ctx *c)
 {
 	size_t m;
 
-	m = tap_send_frames(c, &tcp_l2_iov[0][0], TCP_NUM_IOVS,
+	m = tap_send_frames(c, &tcp6_l2_iov[0][0], TCP_NUM_IOVS,
-			    tcp_payload_used);
+			    tcp6_payload_used);
-	if (m != tcp_payload_used) {
+	if (m != tcp6_payload_used) {
-		tcp_revert_seq(c, &tcp_frame_conns[m], &tcp_l2_iov[m],
+		tcp_revert_seq(c, &tcp6_frame_conns[m], &tcp6_l2_iov[m],
-			       tcp_payload_used - m);
+			       tcp6_payload_used - m);
 	}
-	tcp_payload_used = 0;
+	tcp6_payload_used = 0;
+
+	m = tap_send_frames(c, &tcp4_l2_iov[0][0], TCP_NUM_IOVS,
+			    tcp4_payload_used);
+	if (m != tcp4_payload_used) {
+		tcp_revert_seq(c, &tcp4_frame_conns[m], &tcp4_l2_iov[m],
+			       tcp4_payload_used - m);
+	}
+	tcp4_payload_used = 0;
 }
 
 /**
@@ -155,48 +294,58 @@ void tcp_payload_flush(const struct ctx *c)
  *
  * Return: negative error code on connection reset, 0 otherwise
  */
-int tcp_buf_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
+int tcp_buf_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags)
 {
-	struct tcp_payload_t *payload;
+	struct tcp_flags_t *payload;
 	struct iovec *iov;
 	size_t optlen;
 	size_t l4len;
 	uint32_t seq;
 	int ret;
 
-	iov = tcp_l2_iov[tcp_payload_used];
+	if (CONN_V4(conn))
-	if (CONN_V4(conn)) {
+		iov = tcp4_l2_flags_iov[tcp4_flags_used++];
-		iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp4_payload_ip[tcp_payload_used]);
+	else
-		iov[TCP_IOV_ETH].iov_base = &tcp4_eth_src;
+		iov = tcp6_l2_flags_iov[tcp6_flags_used++];
-	} else {
-		iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp6_payload_ip[tcp_payload_used]);
-		iov[TCP_IOV_ETH].iov_base = &tcp6_eth_src;
-	}
 
 	payload = iov[TCP_IOV_PAYLOAD].iov_base;
+
 	seq = conn->seq_to_tap;
 	ret = tcp_prepare_flags(c, conn, flags, &payload->th,
-				(struct tcp_syn_opts *)&payload->data, &optlen);
+				payload->opts, &optlen);
-	if (ret <= 0)
+	if (ret <= 0) {
+		if (CONN_V4(conn))
+			tcp4_flags_used--;
+		else
+			tcp6_flags_used--;
 		return ret;
-
-	tcp_payload_used++;
-	l4len = tcp_l2_buf_fill_headers(conn, iov, optlen, NULL, seq, false);
-	iov[TCP_IOV_PAYLOAD].iov_len = l4len;
-	if (flags & DUP_ACK) {
-		struct iovec *dup_iov = tcp_l2_iov[tcp_payload_used++];
-
-		memcpy(dup_iov[TCP_IOV_TAP].iov_base, iov[TCP_IOV_TAP].iov_base,
-		       iov[TCP_IOV_TAP].iov_len);
-		dup_iov[TCP_IOV_ETH].iov_base = iov[TCP_IOV_ETH].iov_base;
-		dup_iov[TCP_IOV_IP] = iov[TCP_IOV_IP];
-		memcpy(dup_iov[TCP_IOV_PAYLOAD].iov_base,
-		       iov[TCP_IOV_PAYLOAD].iov_base, l4len);
-		dup_iov[TCP_IOV_PAYLOAD].iov_len = l4len;
 	}
 
-	if (tcp_payload_used > TCP_FRAMES_MEM - 2)
+	l4len = tcp_l2_buf_fill_headers(conn, iov, optlen, NULL, seq);
-		tcp_payload_flush(c);
+	iov[TCP_IOV_PAYLOAD].iov_len = l4len;
+
+	if (flags & DUP_ACK) {
+		struct iovec *dup_iov;
+		int i;
+
+		if (CONN_V4(conn))
+			dup_iov = tcp4_l2_flags_iov[tcp4_flags_used++];
+		else
+			dup_iov = tcp6_l2_flags_iov[tcp6_flags_used++];
+
+		for (i = 0; i < TCP_NUM_IOVS; i++)
+			memcpy(dup_iov[i].iov_base, iov[i].iov_base,
+			       iov[i].iov_len);
+		dup_iov[TCP_IOV_PAYLOAD].iov_len = iov[TCP_IOV_PAYLOAD].iov_len;
+	}
+
+	if (CONN_V4(conn)) {
+		if (tcp4_flags_used > TCP_FRAMES_MEM - 2)
+			tcp_flags_flush(c);
+	} else {
+		if (tcp6_flags_used > TCP_FRAMES_MEM - 2)
+			tcp_flags_flush(c);
+	}
 
 	return 0;
 }
@@ -209,39 +358,39 @@ int tcp_buf_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
  * @no_csum:	Don't compute IPv4 checksum, use the one from previous buffer
  * @seq:	Sequence number to be sent
  */
-static void tcp_data_to_tap(const struct ctx *c, struct tcp_tap_conn *conn,
+static void tcp_data_to_tap(struct ctx *c, struct tcp_tap_conn *conn,
 			    ssize_t dlen, int no_csum, uint32_t seq)
 {
-	struct tcp_payload_t *payload;
-	const uint16_t *check = NULL;
 	struct iovec *iov;
 	size_t l4len;
 
 	conn->seq_to_tap = seq + dlen;
-	tcp_frame_conns[tcp_payload_used] = conn;
-	iov = tcp_l2_iov[tcp_payload_used];
-	if (CONN_V4(conn)) {
-		if (no_csum) {
-			struct iovec *iov_prev = tcp_l2_iov[tcp_payload_used - 1];
-			struct iphdr *iph = iov_prev[TCP_IOV_IP].iov_base;
 
+	if (CONN_V4(conn)) {
+		struct iovec *iov_prev = tcp4_l2_iov[tcp4_payload_used - 1];
+		const uint16_t *check = NULL;
+
+		if (no_csum) {
+			struct iphdr *iph = iov_prev[TCP_IOV_IP].iov_base;
 			check = &iph->check;
 		}
-		iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp4_payload_ip[tcp_payload_used]);
+
-		iov[TCP_IOV_ETH].iov_base = &tcp4_eth_src;
+		tcp4_frame_conns[tcp4_payload_used] = conn;
+
+		iov = tcp4_l2_iov[tcp4_payload_used++];
+		l4len = tcp_l2_buf_fill_headers(conn, iov, dlen, check, seq);
+		iov[TCP_IOV_PAYLOAD].iov_len = l4len;
+		if (tcp4_payload_used > TCP_FRAMES_MEM - 1)
+			tcp_payload_flush(c);
 	} else if (CONN_V6(conn)) {
-		iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp6_payload_ip[tcp_payload_used]);
+		tcp6_frame_conns[tcp6_payload_used] = conn;
-		iov[TCP_IOV_ETH].iov_base = &tcp6_eth_src;
+
+		iov = tcp6_l2_iov[tcp6_payload_used++];
+		l4len = tcp_l2_buf_fill_headers(conn, iov, dlen, NULL, seq);
+		iov[TCP_IOV_PAYLOAD].iov_len = l4len;
+		if (tcp6_payload_used > TCP_FRAMES_MEM - 1)
+			tcp_payload_flush(c);
 	}
-	payload = iov[TCP_IOV_PAYLOAD].iov_base;
-	payload->th.th_off = sizeof(struct tcphdr) / 4;
-	payload->th.th_x2 = 0;
-	payload->th.th_flags = 0;
-	payload->th.ack = 1;
-	l4len = tcp_l2_buf_fill_headers(conn, iov, dlen, check, seq, false);
-	iov[TCP_IOV_PAYLOAD].iov_len = l4len;
-	if (++tcp_payload_used > TCP_FRAMES_MEM - 1)
-		tcp_payload_flush(c);
 }
 
 /**
@@ -253,11 +402,12 @@ static void tcp_data_to_tap(const struct ctx *c, struct tcp_tap_conn *conn,
  *
  * #syscalls recvmsg
  */
-int tcp_buf_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn)
+int tcp_buf_data_from_sock(struct ctx *c, struct tcp_tap_conn *conn)
 {
 	uint32_t wnd_scaled = conn->wnd_from_tap << conn->ws_from_tap;
 	int fill_bufs, send_bufs = 0, last_len, iov_rem = 0;
-	int len, dlen, i, s = conn->sock;
+	int sendlen, len, dlen, v4 = CONN_V4(conn);
+	int s = conn->sock, i, ret = 0;
 	struct msghdr mh_sock = { 0 };
 	uint16_t mss = MSS_GET(conn);
 	uint32_t already_sent, seq;
@@ -304,15 +454,19 @@ int tcp_buf_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn)
 		mh_sock.msg_iovlen = fill_bufs;
 	}
 
-	if (tcp_payload_used + fill_bufs > TCP_FRAMES_MEM) {
+	if (( v4 && tcp4_payload_used + fill_bufs > TCP_FRAMES_MEM) ||
+	    (!v4 && tcp6_payload_used + fill_bufs > TCP_FRAMES_MEM)) {
 		tcp_payload_flush(c);
 
 		/* Silence Coverity CWE-125 false positive */
-		tcp_payload_used = 0;
+		tcp4_payload_used = tcp6_payload_used = 0;
 	}
 
 	for (i = 0, iov = iov_sock + 1; i < fill_bufs; i++, iov++) {
-		iov->iov_base = &tcp_payload[tcp_payload_used + i].data;
+		if (v4)
+			iov->iov_base = &tcp4_payload[tcp4_payload_used + i].data;
+		else
+			iov->iov_base = &tcp6_payload[tcp6_payload_used + i].data;
 		iov->iov_len = mss;
 	}
 	if (iov_rem)
@@ -323,19 +477,12 @@ int tcp_buf_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn)
 		len = recvmsg(s, &mh_sock, MSG_PEEK);
 	while (len < 0 && errno == EINTR);
 
-	if (len < 0) {
+	if (len < 0)
-		if (errno != EAGAIN && errno != EWOULDBLOCK) {
+		goto err;
-			tcp_rst(c, conn);
-			return -errno;
-		}
-
-		return 0;
-	}
 
 	if (!len) {
 		if ((conn->events & (SOCK_FIN_RCVD | TAP_FIN_SENT)) == SOCK_FIN_RCVD) {
-			int ret = tcp_buf_send_flag(c, conn, FIN | ACK);
+			if ((ret = tcp_buf_send_flag(c, conn, FIN | ACK))) {
-			if (ret) {
 				tcp_rst(c, conn);
 				return ret;
 			}
@@ -346,27 +493,28 @@ int tcp_buf_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn)
 		return 0;
 	}
 
+	sendlen = len;
 	if (!peek_offset_cap)
-		len -= already_sent;
+		sendlen -= already_sent;
 
-	if (len <= 0) {
+	if (sendlen <= 0) {
 		conn_flag(c, conn, STALLED);
 		return 0;
 	}
 
 	conn_flag(c, conn, ~STALLED);
 
-	send_bufs = DIV_ROUND_UP(len, mss);
+	send_bufs = DIV_ROUND_UP(sendlen, mss);
-	last_len = len - (send_bufs - 1) * mss;
+	last_len = sendlen - (send_bufs - 1) * mss;
 
 	/* Likely, some new data was acked too. */
-	tcp_update_seqack_wnd(c, conn, false, NULL);
+	tcp_update_seqack_wnd(c, conn, 0, NULL);
 
 	/* Finally, queue to tap */
 	dlen = mss;
 	seq = conn->seq_to_tap;
 	for (i = 0; i < send_bufs; i++) {
-		int no_csum = i && i != send_bufs - 1 && tcp_payload_used;
+		int no_csum = i && i != send_bufs - 1 && tcp4_payload_used;
 
 		if (i == send_bufs - 1)
 			dlen = last_len;
@@ -378,4 +526,12 @@ int tcp_buf_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn)
 	conn_flag(c, conn, ACK_FROM_TAP_DUE);
 
 	return 0;
+
+err:
+	if (errno != EAGAIN && errno != EWOULDBLOCK) {
+		ret = -errno;
+		tcp_rst(c, conn);
+	}
+
+	return ret;
 }

tcp_buf.h

@@ -6,9 +6,11 @@
 #ifndef TCP_BUF_H
 #define TCP_BUF_H
 
-void tcp_sock_iov_init(const struct ctx *c);
+void tcp_sock4_iov_init(const struct ctx *c);
-void tcp_payload_flush(const struct ctx *c);
+void tcp_sock6_iov_init(const struct ctx *c);
-int tcp_buf_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn);
+void tcp_flags_flush(const struct ctx *c);
-int tcp_buf_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags);
+void tcp_payload_flush(struct ctx *c);
+int tcp_buf_data_from_sock(struct ctx *c, struct tcp_tap_conn *conn);
+int tcp_buf_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags);
 
 #endif  /*TCP_BUF_H */

tcp_internal.h

@@ -33,7 +33,9 @@
 #define OPT_EOL		0
 #define OPT_NOP		1
 #define OPT_MSS		2
+#define OPT_MSS_LEN	4
 #define OPT_WS		3
+#define OPT_WS_LEN	3
 #define OPT_SACKP	4
 #define OPT_SACK	5
 #define OPT_TS		8
@@ -61,79 +63,6 @@ enum tcp_iov_parts {
 	TCP_NUM_IOVS
 };
 
-/**
- * struct tcp_payload_t - TCP header and data to send segments with payload
- * @th:		TCP header
- * @data:	TCP data
- */
-struct tcp_payload_t {
-	struct tcphdr th;
-	uint8_t data[IP_MAX_MTU - sizeof(struct tcphdr)];
-#ifdef __AVX2__
-} __attribute__ ((packed, aligned(32)));    /* For AVX2 checksum routines */
-#else
-} __attribute__ ((packed, aligned(__alignof__(unsigned int))));
-#endif
-
-/** struct tcp_opt_nop - TCP NOP option
- * @kind:	Option kind (OPT_NOP = 1)
- */
-struct tcp_opt_nop {
-	uint8_t kind;
-} __attribute__ ((packed));
-#define TCP_OPT_NOP		((struct tcp_opt_nop){ .kind = OPT_NOP, })
-
-/** struct tcp_opt_mss - TCP MSS option
- * @kind:	Option kind (OPT_MSS == 2)
- * @len:	Option length (4)
- * @mss:	Maximum Segment Size
- */
-struct tcp_opt_mss {
-	uint8_t kind;
-	uint8_t len;
-	uint16_t mss;
-} __attribute__ ((packed));
-#define TCP_OPT_MSS(mss_)				\
-	((struct tcp_opt_mss) {				\
-		.kind = OPT_MSS,			\
-		.len = sizeof(struct tcp_opt_mss),	\
-		.mss = htons(mss_),			\
-	})
-
-/** struct tcp_opt_ws - TCP Window Scaling option
- * @kind:	Option kind (OPT_WS == 3)
- * @len:	Option length (3)
- * @shift:	Window scaling shift
- */
-struct tcp_opt_ws {
-	uint8_t kind;
-	uint8_t len;
-	uint8_t shift;
-} __attribute__ ((packed));
-#define TCP_OPT_WS(shift_)				\
-	((struct tcp_opt_ws) {				\
-		.kind = OPT_WS,				\
-		.len = sizeof(struct tcp_opt_ws),	\
-		.shift = (shift_),			\
-	})
-
-/** struct tcp_syn_opts - TCP options we apply to SYN packets
- * @mss:	Maximum Segment Size (MSS) option
- * @nop:	NOP opt (for alignment)
- * @ws:		Window Scaling (WS) option
- */
-struct tcp_syn_opts {
-	struct tcp_opt_mss mss;
-	struct tcp_opt_nop nop;
-	struct tcp_opt_ws ws;
-} __attribute__ ((packed));
-#define TCP_SYN_OPTS(mss_, ws_)				\
-	((struct tcp_syn_opts){				\
-		.mss = TCP_OPT_MSS(mss_),		\
-		.nop = TCP_OPT_NOP,			\
-		.ws = TCP_OPT_WS(ws_),			\
-	})
-
 extern char tcp_buf_discard [MAX_WINDOW];
 
 void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn,
@@ -153,23 +82,19 @@ void conn_event_do(const struct ctx *c, struct tcp_tap_conn *conn,
 		conn_event_do(c, conn, event);				\
 	} while (0)
 
-void tcp_rst_do(const struct ctx *c, struct tcp_tap_conn *conn);
+void tcp_rst_do(struct ctx *c, struct tcp_tap_conn *conn);
 #define tcp_rst(c, conn)						\
 	do {								\
 		flow_dbg((conn), "TCP reset at %s:%i", __func__, __LINE__); \
 		tcp_rst_do(c, conn);					\
 	} while (0)
 
-struct tcp_info_linux;
-
 size_t tcp_l2_buf_fill_headers(const struct tcp_tap_conn *conn,
 			       struct iovec *iov, size_t dlen,
-			       const uint16_t *check, uint32_t seq,
+			       const uint16_t *check, uint32_t seq);
-			       bool no_tcp_csum);
 int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn,
-			  bool force_seq, struct tcp_info_linux *tinfo);
+			  int force_seq, struct tcp_info *tinfo);
-int tcp_prepare_flags(const struct ctx *c, struct tcp_tap_conn *conn,
+int tcp_prepare_flags(struct ctx *c, struct tcp_tap_conn *conn, int flags,
-		      int flags, struct tcphdr *th, struct tcp_syn_opts *opts,
+		      struct tcphdr *th, char *data, size_t *optlen);
-		      size_t *optlen);
 
 #endif /* TCP_INTERNAL_H */

tcp_splice.c

@@ -320,7 +320,7 @@ static int tcp_splice_connect_finish(const struct ctx *c,
 			}
 
 			if (fcntl(conn->pipe[sidei][0], F_SETPIPE_SZ,
-				  c->tcp.pipe_size) != (int)c->tcp.pipe_size) {
+				  c->tcp.pipe_size)) {
 				flow_trace(conn,
 					   "cannot set %d->%d pipe size to %zu",
 					   sidei, !sidei, c->tcp.pipe_size);
@@ -503,7 +503,7 @@ swap:
 	lowat_act_flag = RCVLOWAT_ACT(fromsidei);
 
 	while (1) {
-		ssize_t readlen, written, pending;
+		ssize_t readlen, to_write = 0, written;
 		int more = 0;
 
 retry:
@@ -518,11 +518,14 @@ retry:
 
 			if (errno != EAGAIN)
 				goto close;
+
+			to_write = c->tcp.pipe_size;
 		} else if (!readlen) {
 			eof = 1;
+			to_write = c->tcp.pipe_size;
 		} else {
 			never_read = 0;
-
+			to_write += readlen;
 			if (readlen >= (long)c->tcp.pipe_size * 90 / 100)
 				more = SPLICE_F_MORE;
 
@@ -532,10 +535,10 @@ retry:
 
 eintr:
 		written = splice(conn->pipe[fromsidei][0], NULL,
-				 conn->s[!fromsidei], NULL, c->tcp.pipe_size,
+				 conn->s[!fromsidei], NULL, to_write,
 				 SPLICE_F_MOVE | more | SPLICE_F_NONBLOCK);
 		flow_trace(conn, "%zi from write-side call (passed %zi)",
-			   written, c->tcp.pipe_size);
+			   written, to_write);
 
 		/* Most common case: skip updating counters. */
 		if (readlen > 0 && readlen == written) {
@@ -581,9 +584,10 @@ eintr:
 		if (never_read && written == (long)(c->tcp.pipe_size))
 			goto retry;
 
-		pending = conn->read[fromsidei] - conn->written[fromsidei];
+		if (!never_read && written < to_write) {
-		if (!never_read && written > 0 && written < pending)
+			to_write -= written;
 			goto retry;
+		}
 
 		if (eof)
 			break;
@@ -672,7 +676,7 @@ static void tcp_splice_pipe_refill(const struct ctx *c)
 			continue;
 
 		if (fcntl(splice_pipe_pool[i][0], F_SETPIPE_SZ,
-			  c->tcp.pipe_size) != (int)c->tcp.pipe_size) {
+			  c->tcp.pipe_size)) {
 			trace("TCP (spliced): cannot set pool pipe size to %zu",
 			      c->tcp.pipe_size);
 		}

test/Makefile

@@ -8,6 +8,7 @@
 WGET = wget -c
 
 DEBIAN_IMGS = debian-8.11.0-openstack-amd64.qcow2 \
+	debian-9-nocloud-amd64-daily-20200210-166.qcow2 \
 	debian-10-nocloud-amd64.qcow2 \
 	debian-10-generic-arm64.qcow2 \
 	debian-10-generic-ppc64el-20220911-1135.qcow2 \
@@ -41,7 +42,8 @@ OPENSUSE_IMGS = openSUSE-Leap-15.1-JeOS.x86_64-kvm-and-xen.qcow2 \
 	openSUSE-Leap-15.2-JeOS.x86_64-kvm-and-xen.qcow2 \
 	openSUSE-Leap-15.3-JeOS.x86_64-kvm-and-xen.qcow2 \
 	openSUSE-Tumbleweed-ARM-JeOS-efi.aarch64.raw.xz \
-	openSUSE-Tumbleweed-ARM-JeOS-efi.armv7l.raw.xz
+	openSUSE-Tumbleweed-ARM-JeOS-efi.armv7l.raw.xz \
+	openSUSE-Tumbleweed-JeOS.x86_64-kvm-and-xen.qcow2
 
 UBUNTU_OLD_IMGS = trusty-server-cloudimg-amd64-disk1.img \
 	trusty-server-cloudimg-i386-disk1.img \
@@ -133,6 +135,9 @@ realclean: clean
 debian-8.11.0-openstack-%.qcow2:
 	$(WGET) -O $@ https://cloud.debian.org/images/cloud/OpenStack/archive/8.11.0/debian-8.11.0-openstack-$*.qcow2
 
+debian-9-nocloud-%-daily-20200210-166.qcow2:
+	$(WGET) -O $@ https://cloud.debian.org/images/cloud/stretch/daily/20200210-166/debian-9-nocloud-$*-daily-20200210-166.qcow2
+
 debian-10-nocloud-%.qcow2:
 	$(WGET) -O $@ https://cloud.debian.org/images/cloud/buster/latest/debian-10-nocloud-$*.qcow2
 
@@ -198,6 +203,9 @@ openSUSE-Tumbleweed-ARM-JeOS-efi.aarch64.raw.xz:
 openSUSE-Tumbleweed-ARM-JeOS-efi.armv7l.raw.xz:
 	$(WGET) -O $@ http://download.opensuse.org/ports/armv7hl/tumbleweed/appliances/openSUSE-Tumbleweed-ARM-JeOS-efi.armv7l.raw.xz
 
+openSUSE-Tumbleweed-JeOS.x86_64-kvm-and-xen.qcow2:
+	$(WGET) -O $@ https://download.opensuse.org/tumbleweed/appliances/openSUSE-Tumbleweed-JeOS.x86_64-kvm-and-xen.qcow2
+
 # Ubuntu downloads
 trusty-server-cloudimg-%-disk1.img:
 	$(WGET) -O $@ https://cloud-images.ubuntu.com/trusty/current/trusty-server-cloudimg-$*-disk1.img

test/lib/setup

@@ -58,7 +58,7 @@ setup_passt() {
 	context_run_bg qemu 'qemu-system-'"${QEMU_ARCH}"		   \
 		' -machine accel=kvm'                                      \
 		' -m '${VMEM}' -cpu host -smp '${VCPUS}                    \
-		' -kernel '"${KERNEL}"					   \
+		' -kernel ' "/boot/vmlinuz-$(uname -r)"			   \
 		' -initrd '${INITRAMFS}' -nographic -serial stdio'	   \
 		' -nodefaults'						   \
 		' -append "console=ttyS0 mitigations=off apparmor=0" '	   \
@@ -159,7 +159,7 @@ setup_passt_in_ns() {
 		' -machine accel=kvm'                                      \
 		' -M accel=kvm:tcg'                                        \
 		' -m '${VMEM}' -cpu host -smp '${VCPUS}                    \
-		' -kernel '"${KERNEL}"					   \
+		' -kernel ' "/boot/vmlinuz-$(uname -r)"			   \
 		' -initrd '${INITRAMFS}' -nographic -serial stdio'	   \
 		' -nodefaults'						   \
 		' -append "console=ttyS0 mitigations=off apparmor=0" '	   \
@@ -230,7 +230,7 @@ setup_two_guests() {
 	context_run_bg qemu_1 'qemu-system-'"${QEMU_ARCH}"		     \
 		' -M accel=kvm:tcg'                                          \
 		' -m '${VMEM}' -cpu host -smp '${VCPUS}                      \
-		' -kernel '"${KERNEL}"					     \
+		' -kernel ' "/boot/vmlinuz-$(uname -r)"			     \
 		' -initrd '${INITRAMFS}' -nographic -serial stdio'	     \
 		' -nodefaults'						     \
 		' -append "console=ttyS0 mitigations=off apparmor=0" '	     \
@@ -243,7 +243,7 @@ setup_two_guests() {
 	context_run_bg qemu_2 'qemu-system-'"${QEMU_ARCH}"		     \
 		' -M accel=kvm:tcg'                                          \
 		' -m '${VMEM}' -cpu host -smp '${VCPUS}                      \
-		' -kernel '"${KERNEL}"					     \
+		' -kernel ' "/boot/vmlinuz-$(uname -r)"			     \
 		' -initrd '${INITRAMFS}' -nographic -serial stdio'	     \
 		' -nodefaults'						     \
 		' -append "console=ttyS0 mitigations=off apparmor=0" '	     \

test/lib/term

@@ -31,8 +31,8 @@ PR_DELAY_INIT=100 # ms
 # $@:	Message to print
 info() {
 	tmux select-pane -t ${PANE_INFO}
-	printf "${@}\n" >> $STATEBASE/log_pipe
+	echo "${@}" >> $STATEBASE/log_pipe
-	printf "${@}\n" >> "${LOGFILE}"
+	echo "${@}" >> "${LOGFILE}"
 }
 
 # info_n() - Highlight, print message to pane and to log file without newline
@@ -47,13 +47,13 @@ info_n() {
 # $@:	Message to print
 info_nolog() {
 	tmux select-pane -t ${PANE_INFO}
-	printf "${@}\n" >> $STATEBASE/log_pipe
+	echo "${@}" >> $STATEBASE/log_pipe
 }
 
 # info_nolog() - Print message to log file
 # $@:	Message to print
 log() {
-	printf "${@}\n" >> "${LOGFILE}"
+	echo "${@}" >> "${LOGFILE}"
 }
 
 # info_nolog_n() - Send message to pane without highlighting it, without newline
@@ -664,7 +664,7 @@ pause_continue() {
 
 # run_term() - Start tmux session, running entry point, with recording if needed
 run_term() {
-	TMUX="tmux new-session -s passt_test -eSTATEBASE=$STATEBASE -ePCAP=$PCAP -eDEBUG=$DEBUG -eTRACE=$TRACE -eKERNEL=$KERNEL"
+	TMUX="tmux new-session -s passt_test -eSTATEBASE=$STATEBASE -ePCAP=$PCAP -eDEBUG=$DEBUG"
 
 	if [ ${CI} -eq 1 ]; then
 		printf '\e[8;50;240t'

test/nstool.c

@@ -31,15 +31,10 @@
 
 #define	ARRAY_SIZE(a)	((int)(sizeof(a) / sizeof((a)[0])))
 
-#define die(...)						\
+#define die(...)				\
-	do {							\
+	do {					\
-		fprintf(stderr, "nstool: " __VA_ARGS__);	\
+		fprintf(stderr, __VA_ARGS__);	\
-		exit(1);					\
+		exit(1);			\
-	} while (0)
-
-#define err(...)						\
-	do {							\
-		fprintf(stderr, "nstool: " __VA_ARGS__);	\
 	} while (0)
 
 struct ns_type {
@@ -161,9 +156,6 @@ static int connect_ctl(const char *sockpath, bool wait,
 
 static void cmd_hold(int argc, char *argv[])
 {
-	struct sigaction sa = {
-		.sa_handler = SIG_IGN,
-	};
 	int fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, PF_UNIX);
 	struct sockaddr_un addr;
 	const char *sockpath = argv[1];
@@ -193,10 +185,6 @@ static void cmd_hold(int argc, char *argv[])
 	if (!getcwd(info.cwd, sizeof(info.cwd)))
 		die("getcwd(): %s\n", strerror(errno));
 
-	rc = sigaction(SIGPIPE, &sa, NULL);
-	if (rc)
-		die("sigaction(SIGPIPE): %s\n", strerror(errno));
-
 	do {
 		int afd = accept(fd, NULL, NULL);
 		char buf;
@@ -205,21 +193,17 @@ static void cmd_hold(int argc, char *argv[])
 			die("accept(): %s\n", strerror(errno));
 
 		rc = write(afd, &info, sizeof(info));
-		if (rc < 0) {
+		if (rc < 0)
-			err("holder write() to control socket: %s\n",
+			die("write(): %s\n", strerror(errno));
-			    strerror(errno));
-		}
 		if ((size_t)rc < sizeof(info))
-			err("holder short write() on control socket\n");
+			die("short write() on control socket\n");
 
 		rc = read(afd, &buf, sizeof(buf));
-		if (rc < 0) {
+		if (rc < 0)
-			err("holder read() on control socket: %s\n",
+			die("read(): %s\n", strerror(errno));
-			    strerror(errno));
-		}
 
 		close(afd);
-	} while (rc <= 0);
+	} while (rc == 0);
 
 	unlink(sockpath);
 }
@@ -362,7 +346,7 @@ static int openns(const char *fmt, ...)
 }
 
 static pid_t sig_pid;
-static void sig_propagate(int signum)
+static void sig_handler(int signum)
 {
 	int err;
 
@@ -374,7 +358,7 @@ static void sig_propagate(int signum)
 static void wait_for_child(pid_t pid)
 {
 	struct sigaction sa = {
-		.sa_handler = sig_propagate,
+		.sa_handler = sig_handler,
 		.sa_flags = SA_RESETHAND,
 	};
 	int status, err;

test/passt/dhcp

@@ -49,8 +49,6 @@ check	[ "__SEARCH__" = "__HOST_SEARCH__" ]
 
 test	DHCPv6: address
 guest	/sbin/dhclient -6 __IFNAME__
-# Wait for DAD to complete
-guest	while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
 gout	ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.prefixlen == 128).local] | .[0]'
 hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global" and .deprecated != true).local] | .[0]'
 check	[ "__ADDR6__" = "__HOST_ADDR6__" ]

test/passt/ndp

@@ -16,15 +16,13 @@ htools	ip jq sipcalc grep cut
 
 test	Interface name
 gout	IFNAME ip -j link show | jq -rM '.[] | select(.link_type == "ether").ifname'
-guest	ip link set dev __IFNAME__ up
+guest	ip link set dev __IFNAME__ up && sleep 2
-# Wait for DAD to complete
-guest	while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
 hout	HOST_IFNAME6 ip -j -6 route show|jq -rM '[.[] | select(.dst == "default").dev] | .[0]'
 check	[ -n "__IFNAME__" ]
 
 test	SLAAC: prefix
-gout	ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global" and .protocol == "kernel_ra") | .local + "/" + (.prefixlen | tostring)] | .[0]'
+gout	ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global" and .prefixlen == 64).local] | .[0]'
-gout	PREFIX6 sipcalc __ADDR6__ | grep prefix | cut -d' ' -f4
+gout	PREFIX6 sipcalc __ADDR6__/64 | grep prefix | cut -d' ' -f4
 hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global" and .deprecated != true).local] | .[0]'
 hout	HOST_PREFIX6 sipcalc __HOST_ADDR6__/64 | grep prefix | cut -d' ' -f4
 check	[ "__PREFIX6__" = "__HOST_PREFIX6__" ]

test/passt_in_ns/dhcp

@@ -52,8 +52,6 @@ check	[ "__SEARCH__" = "__HOST_SEARCH__" ]
 
 test	DHCPv6: address
 guest	/sbin/dhclient -6 __IFNAME__
-# Wait for DAD to complete
-guest	while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
 gout	ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.prefixlen == 128).local] | .[0]'
 hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global" and .deprecated != true).local] | .[0]'
 check	[ "__ADDR6__" = "__HOST_ADDR6__" ]

test/passt_in_ns/tcp

@@ -32,7 +32,7 @@ host	socat -u OPEN:__BASEPATH__/big.bin TCP4:127.0.0.1:10001
 guestw
 guest	cmp test_big.bin /root/big.bin
 
-test	TCP/IPv4: host to ns (spliced): big transfer
+test	TCP/IPv4: host to ns: big transfer
 nsb	socat -u TCP4-LISTEN:10002 OPEN:__TEMP_NS_BIG__,create,trunc
 sleep	1
 host	socat -u OPEN:__BASEPATH__/big.bin TCP4:127.0.0.1:10002
@@ -90,7 +90,7 @@ host	socat -u OPEN:__BASEPATH__/small.bin TCP4:127.0.0.1:10001
 guestw
 guest	cmp test_small.bin /root/small.bin
 
-test	TCP/IPv4: host to ns (spliced): small transfer
+test	TCP/IPv4: host to ns: small transfer
 nsb	socat -u TCP4-LISTEN:10002 OPEN:__TEMP_NS_SMALL__,create,trunc
 sleep	1
 host	socat -u OPEN:__BASEPATH__/small.bin TCP4:127.0.0.1:10002
@@ -146,7 +146,7 @@ host	socat -u OPEN:__BASEPATH__/big.bin TCP6:[::1]:10001
 guestw
 guest	cmp test_big.bin /root/big.bin
 
-test	TCP/IPv6: host to ns (spliced): big transfer
+test	TCP/IPv6: host to ns: big transfer
 nsb	socat -u TCP6-LISTEN:10002 OPEN:__TEMP_NS_BIG__,create,trunc
 sleep	1
 host	socat -u OPEN:__BASEPATH__/big.bin TCP6:[::1]:10002
@@ -204,7 +204,7 @@ host	socat -u OPEN:__BASEPATH__/small.bin TCP6:[::1]:10001
 guestw
 guest	cmp test_small.bin /root/small.bin
 
-test	TCP/IPv6: host to ns (spliced): small transfer
+test	TCP/IPv6: host to ns: small transfer
 nsb	socat -u TCP6-LISTEN:10002 OPEN:__TEMP_NS_SMALL__,create,trunc
 sleep	1
 host	socat -u OPEN:__BASEPATH__/small.bin TCP6:[::1]:10002

test/passt_in_ns/udp

@@ -30,7 +30,7 @@ host	socat -u OPEN:__BASEPATH__/medium.bin UDP4:127.0.0.1:10001,shut-null
 guestw
 guest	cmp test.bin /root/medium.bin
 
-test	UDP/IPv4: host to ns (recvmmsg/sendmmsg)
+test	UDP/IPv4: host to ns
 nsb	socat -u UDP4-LISTEN:10002,null-eof OPEN:__TEMP_NS__,create,trunc
 sleep	1
 host	socat -u OPEN:__BASEPATH__/medium.bin UDP4:127.0.0.1:10002,shut-null
@@ -88,7 +88,7 @@ host	socat -u OPEN:__BASEPATH__/medium.bin UDP6:[::1]:10001,shut-null
 guestw
 guest	cmp test.bin /root/medium.bin
 
-test	UDP/IPv6: host to ns (recvmmsg/sendmmsg)
+test	UDP/IPv6: host to ns
 nsb	socat -u UDP6-LISTEN:10002,null-eof OPEN:__TEMP_NS__,create,trunc
 sleep	1
 host	socat -u OPEN:__BASEPATH__/medium.bin UDP6:[::1]:10002,shut-null

test/pasta/dhcp

@@ -35,8 +35,6 @@ check	[ __MTU__ = 65520 ]
 
 test	DHCPv6: address
 ns	/sbin/dhclient -6 --no-pid __IFNAME__
-# Wait for DAD to complete
-ns	while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
 hout	HOST_IFNAME6 ip -j -6 route show|jq -rM '[.[] | select(.dst == "default").dev] | .[0]'
 nsout	ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.prefixlen == 128).local] | .[0]'
 hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global" and .deprecated != true).local] | .[0]'

test/pasta/ndp

@@ -18,12 +18,11 @@ test	Interface name
 nsout	IFNAME ip -j link show | jq -rM '.[] | select(.link_type == "ether").ifname'
 check	[ -n "__IFNAME__" ]
 ns	ip link set dev __IFNAME__ up
-# Wait for DAD to complete
+sleep	2
-ns	while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
 
 test	SLAAC: prefix
-nsout	ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global" and .protocol == "kernel_ra") | .local + "/" + (.prefixlen | tostring)] | .[0]'
+nsout	ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global" and .prefixlen == 64).local] | .[0]'
-nsout	PREFIX6 sipcalc __ADDR6__ | grep prefix | cut -d' ' -f4
+nsout	PREFIX6 sipcalc __ADDR6__/64 | grep prefix | cut -d' ' -f4
 hout	HOST_ADDR6 ip -j -6 addr show|jq -rM ['.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global" and .deprecated != true).local] | .[0]'
 hout	HOST_PREFIX6 sipcalc __HOST_ADDR6__/64 | grep prefix | cut -d' ' -f4
 check	[ "__PREFIX6__" = "__HOST_PREFIX6__" ]

test/pasta/tcp

@@ -19,8 +19,8 @@ set	TEMP_NS_BIG __STATEDIR__/test_ns_big.bin
 set	TEMP_SMALL __STATEDIR__/test_small.bin
 set	TEMP_NS_SMALL __STATEDIR__/test_ns_small.bin
 
-test	TCP/IPv4: host to ns (spliced): big transfer
+test	TCP/IPv4: host to ns: big transfer
-nsb	socat -u TCP4-LISTEN:10002 OPEN:__TEMP_NS_BIG__,create,trunc
+nsb	socat -u TCP4-LISTEN:10002,bind=127.0.0.1 OPEN:__TEMP_NS_BIG__,create,trunc
 host	socat -u OPEN:__BASEPATH__/big.bin TCP4:127.0.0.1:10002
 nsw
 check	cmp __BASEPATH__/big.bin __TEMP_NS_BIG__
@@ -38,8 +38,8 @@ ns	socat -u OPEN:__BASEPATH__/big.bin TCP4:__GW__:10003
 hostw
 check	cmp __BASEPATH__/big.bin __TEMP_BIG__
 
-test	TCP/IPv4: host to ns (spliced): small transfer
+test	TCP/IPv4: host to ns: small transfer
-nsb	socat -u TCP4-LISTEN:10002 OPEN:__TEMP_NS_SMALL__,create,trunc
+nsb	socat -u TCP4-LISTEN:10002,bind=127.0.0.1 OPEN:__TEMP_NS_SMALL__,create,trunc
 host	socat OPEN:__BASEPATH__/small.bin TCP4:127.0.0.1:10002
 nsw
 check	cmp __BASEPATH__/small.bin __TEMP_NS_SMALL__
@@ -57,8 +57,8 @@ ns	socat -u OPEN:__BASEPATH__/small.bin TCP4:__GW__:10003
 hostw
 check	cmp __BASEPATH__/small.bin __TEMP_SMALL__
 
-test	TCP/IPv6: host to ns (spliced): big transfer
+test	TCP/IPv6: host to ns: big transfer
-nsb	socat -u TCP6-LISTEN:10002 OPEN:__TEMP_NS_BIG__,create,trunc
+nsb	socat -u TCP6-LISTEN:10002,bind=[::1] OPEN:__TEMP_NS_BIG__,create,trunc
 host	socat -u OPEN:__BASEPATH__/big.bin TCP6:[::1]:10002
 nsw
 check	cmp __BASEPATH__/big.bin __TEMP_NS_BIG__
@@ -77,8 +77,8 @@ ns	socat -u OPEN:__BASEPATH__/big.bin TCP6:[__GW6__%__IFNAME__]:10003
 hostw
 check	cmp __BASEPATH__/big.bin __TEMP_BIG__
 
-test	TCP/IPv6: host to ns (spliced): small transfer
+test	TCP/IPv6: host to ns: small transfer
-nsb	socat -u TCP6-LISTEN:10002 OPEN:__TEMP_NS_SMALL__,create,trunc
+nsb	socat -u TCP6-LISTEN:10002,bind=[::1] OPEN:__TEMP_NS_SMALL__,create,trunc
 host	socat -u OPEN:__BASEPATH__/small.bin TCP6:[::1]:10002
 nsw
 check	cmp __BASEPATH__/small.bin __TEMP_NS_SMALL__

test/pasta/udp

@@ -17,8 +17,8 @@ htools	dd socat ip jq
 set	TEMP __STATEDIR__/test.bin
 set	TEMP_NS __STATEDIR__/test_ns.bin
 
-test	UDP/IPv4: host to ns (recvmmsg/sendmmsg)
+test	UDP/IPv4: host to ns
-nsb	socat -u UDP4-LISTEN:10002,null-eof OPEN:__TEMP_NS__,create,trunc
+nsb	socat -u UDP4-LISTEN:10002,bind=127.0.0.1,null-eof OPEN:__TEMP_NS__,create,trunc
 host	socat OPEN:__BASEPATH__/medium.bin UDP4:127.0.0.1:10002,shut-null
 nsw
 check	cmp __BASEPATH__/medium.bin __TEMP_NS__
@@ -37,8 +37,8 @@ ns	socat -u OPEN:__BASEPATH__/medium.bin UDP4:__GW__:10003,shut-null
 hostw
 check	cmp __BASEPATH__/medium.bin __TEMP__
 
-test	UDP/IPv6: host to ns (recvmmsg/sendmmsg)
+test	UDP/IPv6: host to ns
-nsb	socat -u UDP6-LISTEN:10002,null-eof OPEN:__TEMP_NS__,create,trunc
+nsb	socat -u UDP6-LISTEN:10002,bind=[::1],null-eof OPEN:__TEMP_NS__,create,trunc
 host	socat -u OPEN:__BASEPATH__/medium.bin UDP6:[::1]:10002,shut-null
 nsw
 check	cmp __BASEPATH__/medium.bin __TEMP_NS__

test/perf/passt_tcp

@@ -116,8 +116,6 @@ iperf3k	ns
 # Reducing MTU below 1280 deconfigures IPv6, get our address back
 guest	dhclient -6 -x
 guest	dhclient -6 __IFNAME__
-# Wait for DAD to complete
-guest	while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
 
 tl	TCP RR latency over IPv4: guest to host
 lat	-

test/perf/pasta_tcp

@@ -211,7 +211,7 @@ tr	TCP throughput over IPv6: host to ns
 iperf3s	ns 10002
 
 nsout	IFNAME ip -j link show | jq -rM '.[] | select(.link_type == "ether").ifname'
-nsout	ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global").local'
+nsout	ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global" and .prefixlen == 64).local'
 bw	-
 bw	-
 bw	-

test/perf/pasta_udp

@@ -196,7 +196,7 @@ tr	UDP throughput over IPv6: host to ns
 iperf3s	ns 10002
 
 nsout	IFNAME ip -j link show | jq -rM '.[] | select(.link_type == "ether").ifname'
-nsout	ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global").local'
+nsout	ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global" and .prefixlen == 64).local'
 iperf3	BW host __ADDR6__ 10002 __TIME__ __OPTS__ -b 8G -l 1472
 bw	__BW__ 0.3 0.5
 iperf3	BW host __ADDR6__ 10002 __TIME__ __OPTS__ -b 12G -l 3972

test/run

@@ -38,9 +38,6 @@ TRACE=${TRACE:-0}
 # If set, tell passt and pasta to take packet captures
 PCAP=${PCAP:-0}
 
-# Custom kernel to boot guests with, if given
-KERNEL=${KERNEL:-"/boot/vmlinuz-$(uname -r)"}
-
 COMMIT="$(git log --oneline --no-decorate -1)"
 
 . lib/util

test/two_guests/basic

@@ -36,13 +36,9 @@ check	[ "__ADDR2__" = "__HOST_ADDR__" ]
 
 test	DHCPv6: addresses
 # Link is up now, wait for DAD to complete
-guest1	while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
+sleep	2
-guest2	while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
 guest1	/sbin/dhclient -6 __IFNAME1__
 guest2	/sbin/dhclient -6 __IFNAME2__
-# Wait for DAD to complete on the DHCP address
-guest1	while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
-guest2	while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
 g1out	ADDR1_6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME1__").addr_info[] | select(.prefixlen == 128).local] | .[0]'
 g2out	ADDR2_6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME2__").addr_info[] | select(.prefixlen == 128).local] | .[0]'
 hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global" and .deprecated != true).local] | .[0]'
@@ -52,33 +48,33 @@ check	[ "__ADDR2_6__" = "__HOST_ADDR6__" ]
 test	TCP/IPv4: guest 1 > guest 2
 g1out	GW1 ip -j -4 route show|jq -rM '.[] | select(.dst == "default").gateway'
 guest2b	socat -u TCP4-LISTEN:10004 OPEN:msg,create,trunc
-sleep	1
 guest1	echo "Hello_from_guest_1" | socat -u STDIN TCP4:__GW1__:10004
 guest2w
+sleep	1
 g2out	MSG2 cat msg
 check	[ "__MSG2__" = "Hello_from_guest_1" ]
 
 test	TCP/IPv6: guest 2 > guest 1
 g2out	GW2_6 ip -j -6 route show|jq -rM '.[] | select(.dst == "default").gateway'
 guest1b	socat -u TCP6-LISTEN:10001 OPEN:msg,create,trunc
-sleep	1
 guest2	echo "Hello_from_guest_2" | socat -u STDIN TCP6:[__GW2_6__%__IFNAME2__]:10001
 guest1w
+sleep	1
 g1out	MSG1 cat msg
 check	[ "__MSG1__" = "Hello_from_guest_2" ]
 
 test	UDP/IPv4: guest 1 > guest 2
 guest2b	socat -u TCP4-LISTEN:10004 OPEN:msg,create,trunc
-sleep	1
 guest1	echo "Hello_from_guest_1" | socat -u STDIN TCP4:__GW1__:10004
 guest2w
+sleep	1
 g2out	MSG2 cat msg
 check	[ "__MSG2__" = "Hello_from_guest_1" ]
 
 test	UDP/IPv6: guest 2 > guest 1
 guest1b	socat -u TCP6-LISTEN:10001 OPEN:msg,create,trunc
-sleep	1
 guest2	echo "Hello_from_guest_2" | socat -u STDIN TCP6:[__GW2_6__%__IFNAME2__]:10001
 guest1w
+sleep	1
 g1out	MSG1 cat msg
 check	[ "__MSG1__" = "Hello_from_guest_2" ]

udp.c

@@ -169,11 +169,11 @@ udp_meta[UDP_MAX_FRAMES];
  * @UDP_NUM_IOVS        the number of entries in the iovec array
  */
 enum udp_iov_idx {
-	UDP_IOV_TAP,
+	UDP_IOV_TAP	= 0,
-	UDP_IOV_ETH,
+	UDP_IOV_ETH	= 1,
-	UDP_IOV_IP,
+	UDP_IOV_IP	= 2,
-	UDP_IOV_PAYLOAD,
+	UDP_IOV_PAYLOAD	= 3,
-	UDP_NUM_IOVS,
+	UDP_NUM_IOVS
 };
 
 /* IOVs and msghdr arrays for receiving datagrams from sockets */
@@ -294,17 +294,15 @@ static void udp_splice_send(const struct ctx *c, size_t start, size_t n,
 
 /**
  * udp_update_hdr4() - Update headers for one IPv4 datagram
- * @ip4h:		Pre-filled IPv4 header (except for tot_len and saddr)
+ * @ip4h:	Pre-filled IPv4 header (except for tot_len and saddr)
- * @bp:			Pointer to udp_payload_t to update
+ * @bp:		Pointer to udp_payload_t to update
- * @toside:		Flowside for destination side
+ * @toside:	Flowside for destination side
- * @dlen:		Length of UDP payload
+ * @dlen:	Length of UDP payload
- * @no_udp_csum:	Do not set UDP checksum
  *
  * Return: size of IPv4 payload (UDP header + data)
  */
 static size_t udp_update_hdr4(struct iphdr *ip4h, struct udp_payload_t *bp,
-			      const struct flowside *toside, size_t dlen,
+			      const struct flowside *toside, size_t dlen)
-			      bool no_udp_csum)
 {
 	const struct in_addr *src = inany_v4(&toside->oaddr);
 	const struct in_addr *dst = inany_v4(&toside->eaddr);
@@ -321,33 +319,22 @@ static size_t udp_update_hdr4(struct iphdr *ip4h, struct udp_payload_t *bp,
 	bp->uh.source = htons(toside->oport);
 	bp->uh.dest = htons(toside->eport);
 	bp->uh.len = htons(l4len);
-	if (no_udp_csum) {
+	csum_udp4(&bp->uh, *src, *dst, bp->data, dlen);
-		bp->uh.check = 0;
-	} else {
-		const struct iovec iov = {
-			.iov_base = bp->data,
-			.iov_len = dlen
-		};
-		csum_udp4(&bp->uh, *src, *dst, &iov, 1, 0);
-	}
 
 	return l4len;
 }
 
 /**
  * udp_update_hdr6() - Update headers for one IPv6 datagram
- * @ip6h:		Pre-filled IPv6 header (except for payload_len and
+ * @ip6h:	Pre-filled IPv6 header (except for payload_len and addresses)
- * 			addresses)
+ * @bp:		Pointer to udp_payload_t to update
- * @bp:			Pointer to udp_payload_t to update
+ * @toside:	Flowside for destination side
- * @toside:		Flowside for destination side
+ * @dlen:	Length of UDP payload
- * @dlen:		Length of UDP payload
- * @no_udp_csum:	Do not set UDP checksum
  *
  * Return: size of IPv6 payload (UDP header + data)
  */
 static size_t udp_update_hdr6(struct ipv6hdr *ip6h, struct udp_payload_t *bp,
-			      const struct flowside *toside, size_t dlen,
+			      const struct flowside *toside, size_t dlen)
-			      bool no_udp_csum)
 {
 	uint16_t l4len = dlen + sizeof(bp->uh);
 
@@ -361,20 +348,7 @@ static size_t udp_update_hdr6(struct ipv6hdr *ip6h, struct udp_payload_t *bp,
 	bp->uh.source = htons(toside->oport);
 	bp->uh.dest = htons(toside->eport);
 	bp->uh.len = ip6h->payload_len;
-	if (no_udp_csum) {
+	csum_udp6(&bp->uh, &toside->oaddr.a6, &toside->eaddr.a6, bp->data, dlen);
-		/* 0 is an invalid checksum for UDP IPv6 and dropped by
-		 * the kernel stack, even if the checksum is disabled by virtio
-		 * flags. We need to put any non-zero value here.
-		 */
-		bp->uh.check = 0xffff;
-	} else {
-		const struct iovec iov = {
-			.iov_base = bp->data,
-			.iov_len = dlen
-		};
-		csum_udp6(&bp->uh, &toside->oaddr.a6, &toside->eaddr.a6,
-			  &iov, 1, 0);
-	}
 
 	return l4len;
 }
@@ -384,11 +358,9 @@ static size_t udp_update_hdr6(struct ipv6hdr *ip6h, struct udp_payload_t *bp,
  * @mmh:	Receiving mmsghdr array
  * @idx:	Index of the datagram to prepare
  * @toside:	Flowside for destination side
- * @no_udp_csum: Do not set UDP checksum
  */
-static void udp_tap_prepare(const struct mmsghdr *mmh,
+static void udp_tap_prepare(const struct mmsghdr *mmh, unsigned idx,
-			    unsigned idx, const struct flowside *toside,
+			    const struct flowside *toside)
-			    bool no_udp_csum)
 {
 	struct iovec (*tap_iov)[UDP_NUM_IOVS] = &udp_l2_iov[idx];
 	struct udp_payload_t *bp = &udp_payload[idx];
@@ -396,15 +368,13 @@ static void udp_tap_prepare(const struct mmsghdr *mmh,
 	size_t l4len;
 
 	if (!inany_v4(&toside->eaddr) || !inany_v4(&toside->oaddr)) {
-		l4len = udp_update_hdr6(&bm->ip6h, bp, toside,
+		l4len = udp_update_hdr6(&bm->ip6h, bp, toside, mmh[idx].msg_len);
-					mmh[idx].msg_len, no_udp_csum);
 		tap_hdr_update(&bm->taph, l4len + sizeof(bm->ip6h) +
 			       sizeof(udp6_eth_hdr));
 		(*tap_iov)[UDP_IOV_ETH] = IOV_OF_LVALUE(udp6_eth_hdr);
 		(*tap_iov)[UDP_IOV_IP] = IOV_OF_LVALUE(bm->ip6h);
 	} else {
-		l4len = udp_update_hdr4(&bm->ip4h, bp, toside,
+		l4len = udp_update_hdr4(&bm->ip4h, bp, toside, mmh[idx].msg_len);
-					mmh[idx].msg_len, no_udp_csum);
 		tap_hdr_update(&bm->taph, l4len + sizeof(bm->ip4h) +
 			       sizeof(udp4_eth_hdr));
 		(*tap_iov)[UDP_IOV_ETH] = IOV_OF_LVALUE(udp4_eth_hdr);
@@ -417,8 +387,7 @@ static void udp_tap_prepare(const struct mmsghdr *mmh,
  * udp_sock_recverr() - Receive and clear an error from a socket
  * @s:		Socket to receive from
  *
- * Return: 1 if error received and processed, 0 if no more errors in queue, < 0
+ * Return: ee_errno, 0 on empty queue
- *         if there was an error reading the queue
  *
  * #syscalls recvmsg
  */
@@ -439,16 +408,15 @@ static int udp_sock_recverr(int s)
 
 	rc = recvmsg(s, &mh, MSG_ERRQUEUE);
 	if (rc < 0) {
-		if (errno == EAGAIN || errno == EWOULDBLOCK)
+		if (errno != EAGAIN && errno != EWOULDBLOCK)
-			return 0;
+			err_perror("Failed to read error queue");
 
-		err_perror("UDP: Failed to read error queue");
+		return 0;
-		return -1;
 	}
 
 	if (!(mh.msg_flags & MSG_ERRQUEUE)) {
 		err("Missing MSG_ERRQUEUE flag reading error queue");
-		return -1;
+		return 0;
 	}
 
 	hdr = CMSG_FIRSTHDR(&mh);
@@ -457,7 +425,7 @@ static int udp_sock_recverr(int s)
 	      (hdr->cmsg_level == IPPROTO_IPV6 &&
 	       hdr->cmsg_type == IPV6_RECVERR))) {
 		err("Unexpected cmsg reading error queue");
-		return -1;
+		return 0;
 	}
 
 	ee = (const struct sock_extended_err *)CMSG_DATA(hdr);
@@ -466,54 +434,7 @@ static int udp_sock_recverr(int s)
 	debug("%s error on UDP socket %i: %s",
 	      str_ee_origin(ee), s, strerror(ee->ee_errno));
 
-	return 1;
+	return ee->ee_errno;
-}
-
-/**
- * udp_sock_errs() - Process errors on a socket
- * @c:		Execution context
- * @s:		Socket to receive from
- * @events:	epoll events bitmap
- *
- * Return: Number of errors handled, or < 0 if we have an unrecoverable error
- */
-static int udp_sock_errs(const struct ctx *c, int s, uint32_t events)
-{
-	unsigned n_err = 0;
-	socklen_t errlen;
-	int rc, err;
-
-	ASSERT(!c->no_udp);
-
-	if (!(events & EPOLLERR))
-		return 0; /* Nothing to do */
-
-	/* Empty the error queue */
-	while ((rc = udp_sock_recverr(s)) > 0)
-		n_err += rc;
-
-	if (rc < 0)
-		return -1; /* error reading error, unrecoverable */
-
-	errlen = sizeof(err);
-	if (getsockopt(s, SOL_SOCKET, SO_ERROR, &err, &errlen) < 0 ||
-	    errlen != sizeof(err)) {
-		err_perror("Error reading SO_ERROR");
-		return -1;  /* error reading error, unrecoverable */
-	}
-
-	if (err) {
-		debug("Unqueued error on UDP socket %i: %s", s, strerror(err));
-		n_err++;
-	}
-
-	if (!n_err) {
-		/* EPOLLERR, but no errors to clear !? */
-		err("EPOLLERR event without reported errors on socket %i", s);
-		return -1; /* no way to clear, unrecoverable */
-	}
-
-	return n_err;
 }
 
 /**
@@ -521,14 +442,15 @@ static int udp_sock_errs(const struct ctx *c, int s, uint32_t events)
  * @c:		Execution context
  * @s:		Socket to receive from
  * @events:	epoll events bitmap
- * @mmh		mmsghdr array to receive into
+ * @mmh:	mmsghdr array to receive into
+ * @recv_err:	Set to last error in queue. If none: -1 on EPOLLERR, 0 otherwise
  *
- * Return: Number of datagrams received
+ * Return: count of datagrams received
  *
  * #syscalls recvmmsg arm:recvmmsg_time64 i686:recvmmsg_time64
  */
 static int udp_sock_recv(const struct ctx *c, int s, uint32_t events,
-			 struct mmsghdr *mmh)
+			 struct mmsghdr *mmh, int *recv_err)
 {
 	/* For not entirely clear reasons (data locality?) pasta gets better
 	 * throughput if we receive tap datagrams one at a atime.  For small
@@ -541,6 +463,17 @@ static int udp_sock_recv(const struct ctx *c, int s, uint32_t events,
 
 	ASSERT(!c->no_udp);
 
+	/* Clear any errors first */
+	if (events & EPOLLERR) {
+		bool found = false;
+		int ret;
+
+		while ((ret = udp_sock_recverr(s)))
+			found = true;
+
+		*recv_err = found ? ret : -1;
+	}
+
 	if (!(events & EPOLLIN))
 		return 0;
 
@@ -566,16 +499,10 @@ void udp_listen_sock_handler(const struct ctx *c, union epoll_ref ref,
 			     uint32_t events, const struct timespec *now)
 {
 	const socklen_t sasize = sizeof(udp_meta[0].s_in);
+	int recv_err = 0;
 	int n, i;
 
-	if (udp_sock_errs(c, ref.fd, events) < 0) {
+	if ((n = udp_sock_recv(c, ref.fd, events, udp_mh_recv, &recv_err)) <= 0)
-		err("UDP: Unrecoverable error on listening socket:"
-		    " (%s port %hu)", pif_name(ref.udp.pif), ref.udp.port);
-		/* FIXME: what now?  close/re-open socket? */
-		return;
-	}
-
-	if ((n = udp_sock_recv(c, ref.fd, events, udp_mh_recv)) <= 0)
 		return;
 
 	/* We divide datagrams into batches based on how we need to send them,
@@ -595,8 +522,7 @@ void udp_listen_sock_handler(const struct ctx *c, union epoll_ref ref,
 				udp_splice_prepare(udp_mh_recv, i);
 			} else if (batchpif == PIF_TAP) {
 				udp_tap_prepare(udp_mh_recv, i,
-						flowside_at_sidx(batchsidx),
+						flowside_at_sidx(batchsidx));
-						false);
 			}
 
 			if (++i >= n)
@@ -644,21 +570,51 @@ void udp_reply_sock_handler(const struct ctx *c, union epoll_ref ref,
 	flow_sidx_t tosidx = flow_sidx_opposite(ref.flowside);
 	const struct flowside *toside = flowside_at_sidx(tosidx);
 	struct udp_flow *uflow = udp_at_sidx(ref.flowside);
+	int from_s = uflow->s[ref.flowside.sidei];
 	uint8_t topif = pif_at_sidx(tosidx);
-	int n, i, from_s;
+	int recv_err = 0;
+	int n, i;
 
 	ASSERT(!c->no_udp && uflow);
 
-	from_s = uflow->s[ref.flowside.sidei];
+	n = udp_sock_recv(c, from_s, events, udp_mh_recv, &recv_err);
+	if (recv_err == -1) {
+		struct flow_common *f = &uflow->f;
+		char estr0[INANY_ADDRSTRLEN], fstr0[INANY_ADDRSTRLEN];
+		char estr1[INANY_ADDRSTRLEN], fstr1[INANY_ADDRSTRLEN];
+		const struct flowside *ini = &f->side[INISIDE];
+		const struct flowside *tgt = &f->side[TGTSIDE];
+
+		flow_err(uflow, "EPOLLERR without error queue, closing flow");
+		err("Last recorded errno was: %i (%s)", uflow->last_errno,
+		    strerror(uflow->last_errno));
+
+		flow_log_(f, LOG_ERR,
+			  "%s [%s]:%hu -> [%s]:%hu => %s [%s]:%hu -> [%s]:%hu",
+			  pif_name(f->pif[INISIDE]),
+			  inany_ntop(&ini->eaddr, estr0, sizeof(estr0)),
+			  ini->eport,
+			  inany_ntop(&ini->oaddr, fstr0, sizeof(fstr0)),
+			  ini->oport,
+			  pif_name(f->pif[TGTSIDE]),
+			  inany_ntop(&tgt->oaddr, fstr1, sizeof(fstr1)),
+			  tgt->oport,
+			  inany_ntop(&tgt->eaddr, estr1, sizeof(estr1)),
+			  tgt->eport);
 
-	if (udp_sock_errs(c, from_s, events) < 0) {
-		flow_err(uflow, "Unrecoverable error on reply socket");
-		flow_err_details(uflow);
 		udp_flow_close(c, uflow);
 		return;
 	}
 
-	if ((n = udp_sock_recv(c, from_s, events, udp_mh_recv)) <= 0)
+	if (recv_err) {
+		struct udp_flow *uflow = udp_at_sidx(udp_meta[0].tosidx);
+
+		uflow->last_errno = recv_err;
+		flow_err(uflow, "Recorded errno %i (%s)", recv_err,
+			 strerror(recv_err));
+	}
+
+	if (n <= 0)
 		return;
 
 	flow_trace(uflow, "Received %d datagrams on reply socket", n);
@@ -668,7 +624,7 @@ void udp_reply_sock_handler(const struct ctx *c, union epoll_ref ref,
 		if (pif_is_socket(topif))
 			udp_splice_prepare(udp_mh_recv, i);
 		else if (topif == PIF_TAP)
-			udp_tap_prepare(udp_mh_recv, i, toside, false);
+			udp_tap_prepare(udp_mh_recv, i, toside);
 		/* Restore sockaddr length clobbered by recvmsg() */
 		udp_mh_recv[i].msg_hdr.msg_namelen = sizeof(udp_meta[i].s_in);
 	}
@@ -795,61 +751,69 @@ int udp_tap_handler(const struct ctx *c, uint8_t pif,
  * udp_sock_init() - Initialise listening sockets for a given port
  * @c:		Execution context
  * @ns:		In pasta mode, if set, bind with loopback address in namespace
+ * @af:		Address family to select a specific IP version, or AF_UNSPEC
  * @addr:	Pointer to address for binding, NULL if not configured
  * @ifname:	Name of interface to bind to, NULL if not configured
  * @port:	Port, host order
  *
  * Return: 0 on (partial) success, negative error code on (complete) failure
  */
-int udp_sock_init(const struct ctx *c, int ns, const union inany_addr *addr,
+int udp_sock_init(const struct ctx *c, int ns, sa_family_t af,
-		  const char *ifname, in_port_t port)
+		  const void *addr, const char *ifname, in_port_t port)
 {
-	union udp_listen_epoll_ref uref = {
+	union udp_listen_epoll_ref uref = { .port = port };
-		.pif = ns ? PIF_SPLICE : PIF_HOST,
-		.port = port,
-	};
 	int r4 = FD_REF_MAX + 1, r6 = FD_REF_MAX + 1;
 
 	ASSERT(!c->no_udp);
 
-	if (!addr && c->ifi4 && c->ifi6 && !ns) {
+	if (ns)
+		uref.pif = PIF_SPLICE;
+	else
+		uref.pif = PIF_HOST;
+
+	if (af == AF_UNSPEC && c->ifi4 && c->ifi6) {
 		int s;
 
 		/* Attempt to get a dual stack socket */
-		s = pif_sock_l4(c, EPOLL_TYPE_UDP_LISTEN, PIF_HOST,
+		if (!ns) {
-				NULL, ifname, port, uref.u32);
+			s = sock_l4(c, AF_UNSPEC, EPOLL_TYPE_UDP_LISTEN,
-		udp_splice_init[V4][port] = s < 0 ? -1 : s;
+				    addr, ifname, port, uref.u32);
-		udp_splice_init[V6][port] = s < 0 ? -1 : s;
+			udp_splice_init[V4][port] = s < 0 ? -1 : s;
+			udp_splice_init[V6][port] = s < 0 ? -1 : s;
+		} else {
+			s = sock_l4(c, AF_UNSPEC, EPOLL_TYPE_UDP_LISTEN,
+				    &in4addr_loopback, ifname, port, uref.u32);
+			udp_splice_ns[V4][port] = s < 0 ? -1 : s;
+			udp_splice_ns[V6][port] = s < 0 ? -1 : s;
+		}
 		if (IN_INTERVAL(0, FD_REF_MAX, s))
 			return 0;
 	}
 
-	if ((!addr || inany_v4(addr)) && c->ifi4) {
+	if ((af == AF_INET || af == AF_UNSPEC) && c->ifi4) {
 		if (!ns) {
-			r4 = pif_sock_l4(c, EPOLL_TYPE_UDP_LISTEN, PIF_HOST,
+			r4 = sock_l4(c, AF_INET, EPOLL_TYPE_UDP_LISTEN,
-					 addr ? addr : &inany_any4, ifname,
+				     addr, ifname, port, uref.u32);
-					 port, uref.u32);
 
 			udp_splice_init[V4][port] = r4 < 0 ? -1 : r4;
 		} else {
-			r4  = pif_sock_l4(c, EPOLL_TYPE_UDP_LISTEN, PIF_SPLICE,
+			r4  = sock_l4(c, AF_INET, EPOLL_TYPE_UDP_LISTEN,
-					  &inany_loopback4, ifname,
+				      &in4addr_loopback,
-					  port, uref.u32);
+				      ifname, port, uref.u32);
 			udp_splice_ns[V4][port] = r4 < 0 ? -1 : r4;
 		}
 	}
 
-	if ((!addr || !inany_v4(addr)) && c->ifi6) {
+	if ((af == AF_INET6 || af == AF_UNSPEC) && c->ifi6) {
 		if (!ns) {
-			r6 = pif_sock_l4(c, EPOLL_TYPE_UDP_LISTEN, PIF_HOST,
+			r6 = sock_l4(c, AF_INET6, EPOLL_TYPE_UDP_LISTEN,
-					 addr ? addr : &inany_any6, ifname,
+				     addr, ifname, port, uref.u32);
-					 port, uref.u32);
 
 			udp_splice_init[V6][port] = r6 < 0 ? -1 : r6;
 		} else {
-			r6 = pif_sock_l4(c, EPOLL_TYPE_UDP_LISTEN, PIF_SPLICE,
+			r6 = sock_l4(c, AF_INET6, EPOLL_TYPE_UDP_LISTEN,
-					 &inany_loopback6, ifname,
+				     &in6addr_loopback,
-					 port, uref.u32);
+				     ifname, port, uref.u32);
 			udp_splice_ns[V6][port] = r6 < 0 ? -1 : r6;
 		}
 	}
@@ -917,7 +881,7 @@ static void udp_port_rebind(struct ctx *c, bool outbound)
 
 		if ((c->ifi4 && socks[V4][port] == -1) ||
 		    (c->ifi6 && socks[V6][port] == -1))
-			udp_sock_init(c, outbound, NULL, NULL, port);
+			udp_sock_init(c, outbound, AF_UNSPEC, NULL, NULL, port);
 	}
 }
 

udp.h

@@ -16,8 +16,8 @@ void udp_reply_sock_handler(const struct ctx *c, union epoll_ref ref,
 int udp_tap_handler(const struct ctx *c, uint8_t pif,
 		    sa_family_t af, const void *saddr, const void *daddr,
 		    const struct pool *p, int idx, const struct timespec *now);
-int udp_sock_init(const struct ctx *c, int ns, const union inany_addr *addr,
+int udp_sock_init(const struct ctx *c, int ns, sa_family_t af,
-		  const char *ifname, in_port_t port);
+		  const void *addr, const char *ifname, in_port_t port);
 int udp_init(struct ctx *c);
 void udp_timer(struct ctx *c, const struct timespec *now);
 void udp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s);

udp_flow.c

@@ -34,16 +34,13 @@ struct udp_flow *udp_at_sidx(flow_sidx_t sidx)
 	return &flow->udp;
 }
 
-/*
+/**
  * udp_flow_close() - Close and clean up UDP flow
  * @c:		Execution context
  * @uflow:	UDP flow
  */
 void udp_flow_close(const struct ctx *c, struct udp_flow *uflow)
 {
-	if (uflow->closed)
-		return; /* Nothing to do */
-
 	if (uflow->s[INISIDE] >= 0) {
 		/* The listening socket needs to stay in epoll */
 		close(uflow->s[INISIDE]);
@@ -56,11 +53,12 @@ void udp_flow_close(const struct ctx *c, struct udp_flow *uflow)
 		close(uflow->s[TGTSIDE]);
 		uflow->s[TGTSIDE] = -1;
 	}
+
+	uflow->last_errno = 0;
+
 	flow_hash_remove(c, FLOW_SIDX(uflow, INISIDE));
 	if (!pif_is_socket(uflow->f.pif[TGTSIDE]))
 		flow_hash_remove(c, FLOW_SIDX(uflow, TGTSIDE));
-
-	uflow->closed = true;
 }
 
 /**
@@ -261,17 +259,6 @@ flow_sidx_t udp_flow_from_tap(const struct ctx *c,
 	return udp_flow_new(c, flow, -1, now);
 }
 
-/**
- * udp_flow_defer() - Deferred per-flow handling (clean up aborted flows)
- * @uflow:	Flow to handle
- *
- * Return: true if the connection is ready to free, false otherwise
- */
-bool udp_flow_defer(const struct udp_flow *uflow)
-{
-	return uflow->closed;
-}
-
 /**
  * udp_flow_timer() - Handler for timed events related to a given flow
  * @c:		Execution context

udp_flow.h

@@ -10,7 +10,6 @@
 /**
  * struct udp - Descriptor for a flow of UDP packets
  * @f:		Generic flow information
- * @closed:	Flow is already closed
  * @ts:		Activity timestamp
  * @s:		Socket fd (or -1) for each side of the flow
  */
@@ -18,9 +17,10 @@ struct udp_flow {
 	/* Must be first element */
 	struct flow_common f;
 
-	bool closed :1;
 	time_t ts;
 	int s[SIDES];
+
+	int last_errno;
 };
 
 struct udp_flow *udp_at_sidx(flow_sidx_t sidx);
@@ -33,7 +33,6 @@ flow_sidx_t udp_flow_from_tap(const struct ctx *c,
 			      in_port_t srcport, in_port_t dstport,
 			      const struct timespec *now);
 void udp_flow_close(const struct ctx *c, struct udp_flow *uflow);
-bool udp_flow_defer(const struct udp_flow *uflow);
 bool udp_flow_timer(const struct ctx *c, struct udp_flow *uflow,
 		    const struct timespec *now);
 

util.c

@@ -28,7 +28,6 @@
 #include <linux/errqueue.h>
 #include <getopt.h>
 
-#include "linux_dep.h"
 #include "util.h"
 #include "iov.h"
 #include "passt.h"
@@ -53,7 +52,6 @@ int sock_l4_sa(const struct ctx *c, enum epoll_type type,
 {
 	sa_family_t af = ((const struct sockaddr *)sa)->sa_family;
 	union epoll_ref ref = { .type = type, .data = data };
-	bool freebind = false;
 	struct epoll_event ev;
 	int fd, y = 1, ret;
 	uint8_t proto;
@@ -63,11 +61,8 @@ int sock_l4_sa(const struct ctx *c, enum epoll_type type,
 	case EPOLL_TYPE_TCP_LISTEN:
 		proto = IPPROTO_TCP;
 		socktype = SOCK_STREAM | SOCK_NONBLOCK;
-		freebind = c->freebind;
 		break;
 	case EPOLL_TYPE_UDP_LISTEN:
-		freebind = c->freebind;
-		/* fallthrough */
 	case EPOLL_TYPE_UDP_REPLY:
 		proto = IPPROTO_UDP;
 		socktype = SOCK_DGRAM | SOCK_NONBLOCK;
@@ -132,18 +127,6 @@ int sock_l4_sa(const struct ctx *c, enum epoll_type type,
 		}
 	}
 
-	if (freebind) {
-		int level = af == AF_INET ? IPPROTO_IP : IPPROTO_IPV6;
-		int opt = af == AF_INET ? IP_FREEBIND : IPV6_FREEBIND;
-
-		if (setsockopt(fd, level, opt, &y, sizeof(y))) {
-			err_perror("Failed to set %s on socket %i",
-				   af == AF_INET ? "IP_FREEBIND"
-				                 : "IPV6_FREEBIND",
-				   fd);
-		}
-	}
-
 	if (bind(fd, sa, sl) < 0) {
 		/* We'll fail to bind to low ports if we don't have enough
 		 * capabilities, and we'll fail to bind on already bound ports,
@@ -174,6 +157,58 @@ int sock_l4_sa(const struct ctx *c, enum epoll_type type,
 
 	return fd;
 }
+/**
+ * sock_l4() - Create and bind socket for given L4, add to epoll list
+ * @c:		Execution context
+ * @af:		Address family, AF_INET or AF_INET6
+ * @type:	epoll type
+ * @bind_addr:	Address for binding, NULL for any
+ * @ifname:	Interface for binding, NULL for any
+ * @port:	Port, host order
+ * @data:	epoll reference portion for protocol handlers
+ *
+ * Return: newly created socket, negative error code on failure
+ */
+int sock_l4(const struct ctx *c, sa_family_t af, enum epoll_type type,
+	    const void *bind_addr, const char *ifname, uint16_t port,
+	    uint32_t data)
+{
+	switch (af) {
+	case AF_INET: {
+		struct sockaddr_in addr4 = {
+			.sin_family = AF_INET,
+			.sin_port = htons(port),
+			{ 0 }, { 0 },
+		};
+		if (bind_addr)
+			addr4.sin_addr = *(struct in_addr *)bind_addr;
+		return sock_l4_sa(c, type, &addr4, sizeof(addr4), ifname,
+				  false, data);
+	}
+
+	case AF_UNSPEC:
+		if (!DUAL_STACK_SOCKETS || bind_addr)
+			 return -EINVAL;
+		/* fallthrough */
+	case AF_INET6: {
+		struct sockaddr_in6 addr6 = {
+			.sin6_family = AF_INET6,
+			.sin6_port = htons(port),
+			0, IN6ADDR_ANY_INIT, 0,
+		};
+		if (bind_addr) {
+			addr6.sin6_addr = *(struct in6_addr *)bind_addr;
+
+			if (IN6_IS_ADDR_LINKLOCAL(bind_addr))
+				addr6.sin6_scope_id = c->ifi6;
+		}
+		return sock_l4_sa(c, type, &addr6, sizeof(addr6), ifname,
+				  af == AF_INET6, data);
+	}
+	default:
+		return -EINVAL;
+	}
+}
 
 /**
  * sock_probe_mem() - Check if setting high SO_SNDBUF and SO_RCVBUF is allowed
@@ -184,8 +219,7 @@ void sock_probe_mem(struct ctx *c)
 	int v = INT_MAX / 2, s;
 	socklen_t sl;
 
-	s = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);
+	if ((s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) {
-	if (s < 0) {
 		c->low_wmem = c->low_rmem = 1;
 		return;
 	}
@@ -215,7 +249,7 @@ void sock_probe_mem(struct ctx *c)
 int64_t timespec_diff_us(const struct timespec *a, const struct timespec *b)
 {
 	if (a->tv_nsec < b->tv_nsec) {
-		return (a->tv_nsec + 1000000000 - b->tv_nsec) / 1000 +
+		return (b->tv_nsec - a->tv_nsec) / 1000 +
 		       (a->tv_sec - b->tv_sec - 1) * 1000000;
 	}
 
@@ -409,20 +443,25 @@ void pidfile_write(int fd, pid_t pid)
 }
 
 /**
- * output_file_open() - Open file for output, if needed
+ * pidfile_open() - Open PID file if needed
- * @path:	Path for output file
+ * @path:	Path for PID file, empty string if no PID file is requested
- * @flags:	Flags for open() other than O_CREAT, O_TRUNC, O_CLOEXEC
  *
- * Return: file descriptor on success, -1 on failure with errno set by open()
+ * Return: descriptor for PID file, -1 if path is NULL, won't return on failure
  */
-int output_file_open(const char *path, int flags)
+int pidfile_open(const char *path)
 {
-	/* We use O_CLOEXEC here, but clang-tidy as of LLVM 16 to 19 looks for
+	int fd;
-	 * it in the 'mode' argument if we have one
+
-	 */
+	if (!*path)
-	return open(path, O_CREAT | O_TRUNC | O_CLOEXEC | flags,
+		return -1;
-		    /* NOLINTNEXTLINE(android-cloexec-open) */
+
-		    S_IRUSR | S_IWUSR);
+	if ((fd = open(path, O_CREAT | O_TRUNC | O_WRONLY | O_CLOEXEC,
+			     S_IRUSR | S_IWUSR)) < 0) {
+		perror("PID file open");
+		exit(EXIT_FAILURE);
+	}
+
+	return fd;
 }
 
 /**
@@ -446,11 +485,16 @@ int __daemon(int pidfile_fd, int devnull_fd)
 		exit(EXIT_SUCCESS);
 	}
 
-	if (setsid()				< 0 ||
+	errno = 0;
-	    dup2(devnull_fd, STDIN_FILENO)	< 0 ||
+
-	    dup2(devnull_fd, STDOUT_FILENO)	< 0 ||
+	setsid();
-	    dup2(devnull_fd, STDERR_FILENO)	< 0 ||
+
-	    close(devnull_fd))
+	dup2(devnull_fd, STDIN_FILENO);
+	dup2(devnull_fd, STDOUT_FILENO);
+	dup2(devnull_fd, STDERR_FILENO);
+	close(devnull_fd);
+
+	if (errno)
 		exit(EXIT_FAILURE);
 
 	return 0;
@@ -538,36 +582,6 @@ int do_clone(int (*fn)(void *), char *stack_area, size_t stack_size, int flags,
 #endif
 }
 
-/* write_all_buf() - write all of a buffer to an fd
- * @fd:		File descriptor
- * @buf:	Pointer to base of buffer
- * @len:	Length of buffer
- *
- * Return: 0 on success, -1 on error (with errno set)
- *
- * #syscalls write
- */
-int write_all_buf(int fd, const void *buf, size_t len)
-{
-	const char *p = buf;
-	size_t left = len;
-
-	while (left) {
-		ssize_t rc;
-
-		do
-			rc = write(fd, p, left);
-		while ((rc < 0) && errno == EINTR);
-
-		if (rc < 0)
-			return -1;
-
-		p += rc;
-		left -= rc;
-	}
-	return 0;
-}
-
 /* write_remainder() - write the tail of an IO vector to an fd
  * @fd:		File descriptor
  * @iov:	IO vector
@@ -576,30 +590,28 @@ int write_all_buf(int fd, const void *buf, size_t len)
  *
  * Return: 0 on success, -1 on error (with errno set)
  *
- * #syscalls writev
+ * #syscalls write writev
  */
 int write_remainder(int fd, const struct iovec *iov, size_t iovcnt, size_t skip)
 {
-	size_t i = 0, offset;
+	size_t offset, i;
 
-	while ((i += iov_skip_bytes(iov + i, iovcnt - i, skip, &offset)) < iovcnt) {
+	while ((i = iov_skip_bytes(iov, iovcnt, skip, &offset)) < iovcnt) {
 		ssize_t rc;
 
 		if (offset) {
-			/* Write the remainder of the partially written buffer */
+			rc = write(fd, (char *)iov[i].iov_base + offset,
-			if (write_all_buf(fd, (char *)iov[i].iov_base + offset,
+				   iov[i].iov_len - offset);
-					  iov[i].iov_len - offset) < 0)
+		} else {
-				return -1;
+			rc = writev(fd, &iov[i], iovcnt - i);
-			i++;
 		}
 
-		/* Write as much of the remaining whole buffers as we can */
-		rc = writev(fd, &iov[i], iovcnt - i);
 		if (rc < 0)
 			return -1;
 
-		skip = rc;
+		skip += rc;
 	}
+
 	return 0;
 }
 
@@ -738,48 +750,6 @@ void close_open_files(int argc, char **argv)
 			rc = close_range(fd + 1, ~0U, CLOSE_RANGE_UNSHARE);
 	}
 
-	if (rc) {
+	if (rc)
-		if (errno == ENOSYS || errno == EINVAL) {
+		die_perror("Failed to close files leaked by parent");
-			/* This probably means close_range() or the
-			 * CLOSE_RANGE_UNSHARE flag is not supported by the
-			 * kernel.  Not much we can do here except carry on and
-			 * hope for the best.
-			 */
-			warn(
-"Can't use close_range() to ensure no files leaked by parent");
-		} else {
-			die_perror("Failed to close files leaked by parent");
-		}
-	}
-
-}
-
-/**
- * snprintf_check() - snprintf() wrapper, checking for truncation and errors
- * @str:	Output buffer
- * @size:	Maximum size to write to @str
- * @format:	Message
- *
- * Return: false on success, true on truncation or error, sets errno on failure
- */
-bool snprintf_check(char *str, size_t size, const char *format, ...)
-{
-	va_list ap;
-	int rc;
-
-	va_start(ap, format);
-	rc = vsnprintf(str, size, format, ap);
-	va_end(ap);
-
-	if (rc < 0) {
-		errno = EIO;
-		return true;
-	}
-
-	if ((size_t)rc >= size) {
-		errno = ENOBUFS;
-		return true;
-	}
-
-	return false;
 }

util.h

@@ -11,12 +11,12 @@
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
-#include <stdio.h>
 #include <string.h>
 #include <signal.h>
 #include <arpa/inet.h>
 #include <unistd.h>
 #include <sys/syscall.h>
+#include <linux/close_range.h>
 
 #include "log.h"
 
@@ -67,15 +67,6 @@
 #define STRINGIFY(x)	#x
 #define STR(x)		STRINGIFY(x)
 
-#ifdef CPPCHECK_6936
-/* Some cppcheck versions get confused by aborts inside a loop, causing
- * it to give false positive uninitialised variable warnings later in
- * the function, because it doesn't realise the non-initialising path
- * already exited.  See https://trac.cppcheck.net/ticket/13227
- */
-#define ASSERT(expr)		\
-	((expr) ? (void)0 : abort())
-#else
 #define ASSERT(expr)							\
 	do {								\
 		if (!(expr)) {						\
@@ -87,7 +78,6 @@
 			abort();					\
 		}							\
 	} while (0)
-#endif
 
 #ifdef P_tmpdir
 #define TMPDIR		P_tmpdir
@@ -101,9 +91,6 @@
 
 #define ARRAY_SIZE(a)		((int)(sizeof(a) / sizeof((a)[0])))
 
-#define foreach(item, array)						\
-	for ((item) = (array); (item) - (array) < ARRAY_SIZE(array); (item)++)
-
 #define IN_INTERVAL(a, b, x)	((x) >= (a) && (x) <= (b))
 #define FD_PROTO(x, proto)						\
 	(IN_INTERVAL(c->proto.fd_min, c->proto.fd_max, (x)))
@@ -144,7 +131,7 @@ static inline uint32_t ntohl_unaligned(const void *p)
 	return ntohl(val);
 }
 
-#define NS_FN_STACK_SIZE	(1024 * 1024) /* 1MiB */
+#define NS_FN_STACK_SIZE	(RLIMIT_STACK_VAL * 1024 / 8)
 int do_clone(int (*fn)(void *), char *stack_area, size_t stack_size, int flags,
 	     void *arg);
 #define NS_CALL(fn, arg)						\
@@ -157,9 +144,9 @@ int do_clone(int (*fn)(void *), char *stack_area, size_t stack_size, int flags,
 			 (void *)(arg));				\
 	} while (0)
 
-#define RCVBUF_BIG		(2ULL * 1024 * 1024)
+#define RCVBUF_BIG		(2UL * 1024 * 1024)
-#define SNDBUF_BIG		(4ULL * 1024 * 1024)
+#define SNDBUF_BIG		(4UL * 1024 * 1024)
-#define SNDBUF_SMALL		(128ULL * 1024)
+#define SNDBUF_SMALL		(128UL * 1024)
 
 #include <net/if.h>
 #include <limits.h>
@@ -170,9 +157,33 @@ int do_clone(int (*fn)(void *), char *stack_area, size_t stack_size, int flags,
 
 struct ctx;
 
+/* cppcheck-suppress funcArgNamesDifferent */
+__attribute__ ((weak)) int ffsl(long int i) { return __builtin_ffsl(i); }
+
+#ifdef CLOSE_RANGE_UNSHARE	/* Linux kernel >= 5.9 */
+/* glibc < 2.34 and musl as of 1.2.5 need these */
+#ifndef SYS_close_range
+#define SYS_close_range		436
+#endif
+__attribute__ ((weak))
+/* cppcheck-suppress funcArgNamesDifferent */
+int close_range(unsigned int first, unsigned int last, int flags) {
+	return syscall(SYS_close_range, first, last, flags);
+}
+#else
+/* No reasonable fallback option */
+/* cppcheck-suppress funcArgNamesDifferent */
+int close_range(unsigned int first, unsigned int last, int flags) {
+	return 0;
+}
+#endif
+
 int sock_l4_sa(const struct ctx *c, enum epoll_type type,
 	       const void *sa, socklen_t sl,
 	       const char *ifname, bool v6only, uint32_t data);
+int sock_l4(const struct ctx *c, sa_family_t af, enum epoll_type type,
+	    const void *bind_addr, const char *ifname, uint16_t port,
+	    uint32_t data);
 void sock_probe_mem(struct ctx *c);
 long timespec_diff_ms(const struct timespec *a, const struct timespec *b);
 int64_t timespec_diff_us(const struct timespec *a, const struct timespec *b);
@@ -184,15 +195,13 @@ char *line_read(char *buf, size_t len, int fd);
 void ns_enter(const struct ctx *c);
 bool ns_is_init(void);
 int open_in_ns(const struct ctx *c, const char *path, int flags);
-int output_file_open(const char *path, int flags);
+int pidfile_open(const char *path);
 void pidfile_write(int fd, pid_t pid);
 int __daemon(int pidfile_fd, int devnull_fd);
 int fls(unsigned long x);
 int write_file(const char *path, const char *buf);
-int write_all_buf(int fd, const void *buf, size_t len);
 int write_remainder(int fd, const struct iovec *iov, size_t iovcnt, size_t skip);
 void close_open_files(int argc, char **argv);
-bool snprintf_check(char *str, size_t size, const char *format, ...);
 
 /**
  * af_name() - Return name of an address family
@@ -260,9 +269,6 @@ static inline bool mod_between(unsigned x, unsigned i, unsigned j, unsigned m)
 	return mod_sub(x, i, m) < mod_sub(j, i, m);
 }
 
-/* FPRINTF() intentionally silences cert-err33-c clang-tidy warnings */
-#define FPRINTF(f, ...)	(void)fprintf(f, __VA_ARGS__)
-
 /*
  * Workarounds for https://github.com/llvm/llvm-project/issues/58992
  *