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flow, tcp: Generalise connection types

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Currently TCP connections use a 1-bit selector, 'spliced', to determine the
rest of the contents of the structure.  We want to generalise the TCP
connection table to other types of flows in other protocols.  Make a start
on this by replacing the tcp_conn_common structure with a new flow_common
structure with an enum rather than a simple boolean indicating the type of
flow.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
David Gibson 2023-11-30 13:02:08 +11:00 committed by Stefano Brivio
parent ba84a3b17a
commit 16ae032608
6 changed files with 112 additions and 40 deletions
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8
Makefile
View file

@ -44,15 +44,15 @@ FLAGS += -DARCH=\"$(TARGET_ARCH)\"
FLAGS += -DVERSION=\"$(VERSION)\"
FLAGS += -DDUAL_STACK_SOCKETS=$(DUAL_STACK_SOCKETS)
PASST_SRCS = arch.c arp.c checksum.c conf.c dhcp.c dhcpv6.c icmp.c igmp.c \
isolation.c lineread.c log.c mld.c ndp.c netlink.c packet.c passt.c \
pasta.c pcap.c port_fwd.c tap.c tcp.c tcp_splice.c udp.c util.c
PASST_SRCS = arch.c arp.c checksum.c conf.c dhcp.c dhcpv6.c flow.c icmp.c \
igmp.c isolation.c lineread.c log.c mld.c ndp.c netlink.c packet.c \
passt.c pasta.c pcap.c port_fwd.c tap.c tcp.c tcp_splice.c udp.c util.c
QRAP_SRCS = qrap.c
SRCS = $(PASST_SRCS) $(QRAP_SRCS)
MANPAGES = passt.1 pasta.1 qrap.1
PASST_HEADERS = arch.h arp.h checksum.h conf.h dhcp.h dhcpv6.h icmp.h \
PASST_HEADERS = arch.h arp.h checksum.h conf.h dhcp.h dhcpv6.h flow.h icmp.h \
inany.h isolation.h lineread.h log.h ndp.h netlink.h packet.h passt.h \
pasta.h pcap.h pif.h port_fwd.h siphash.h tap.h tcp.h tcp_conn.h \
tcp_splice.h udp.h util.h

18
flow.c Normal file
View file

@ -0,0 +1,18 @@
/* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright Red Hat
* Author: David Gibson <david@gibson.dropbear.id.au>
*
* Tracking for logical "flows" of packets.
*/
#include <stdint.h>
#include "flow.h"
const char *flow_type_str[] = {
[FLOW_TYPE_NONE] = "<none>",
[FLOW_TCP] = "TCP connection",
[FLOW_TCP_SPLICE] = "TCP connection (spliced)",
};
static_assert(ARRAY_SIZE(flow_type_str) == FLOW_NUM_TYPES,
"flow_type_str[] doesn't match enum flow_type");

36
flow.h Normal file
View file

@ -0,0 +1,36 @@
/* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright Red Hat
* Author: David Gibson <david@gibson.dropbear.id.au>
*
* Tracking for logical "flows" of packets.
*/
#ifndef FLOW_H
#define FLOW_H
/**
* enum flow_type - Different types of packet flows we track
*/
enum flow_type {
/* Represents an invalid or unused flow */
FLOW_TYPE_NONE = 0,
/* A TCP connection between a socket and tap interface */
FLOW_TCP,
/* A TCP connection between a host socket and ns socket */
FLOW_TCP_SPLICE,
FLOW_NUM_TYPES,
};
extern const char *flow_type_str[];
#define FLOW_TYPE(f) \
((f)->type < FLOW_NUM_TYPES ? flow_type_str[(f)->type] : "?")
/**
* struct flow_common - Common fields for packet flows
* @type: Type of packet flow
*/
struct flow_common {
uint8_t type;
};
#endif /* FLOW_H */

63
tcp.c
View file

@ -299,6 +299,7 @@
#include "tcp_splice.h"
#include "log.h"
#include "inany.h"
#include "flow.h"
#include "tcp_conn.h"
@ -584,7 +585,7 @@ static inline struct tcp_tap_conn *conn_at_idx(int idx)
{
if ((idx < 0) || (idx >= TCP_MAX_CONNS))
return NULL;
ASSERT(!(CONN(idx)->c.spliced));
ASSERT(CONN(idx)->f.type == FLOW_TCP);
return CONN(idx);
}
@ -1319,14 +1320,21 @@ void tcp_table_compact(struct ctx *c, union tcp_conn *hole)
from = tc + c->tcp.conn_count;
memcpy(hole, from, sizeof(*hole));
if (from->c.spliced)
tcp_splice_conn_update(c, &hole->splice);
else
switch (from->f.type) {
case FLOW_TCP:
tcp_tap_conn_update(c, &from->tap, &hole->tap);
break;
case FLOW_TCP_SPLICE:
tcp_splice_conn_update(c, &hole->splice);
break;
default:
die("Unexpected %s in tcp_table_compact()",
FLOW_TYPE(&from->f));
}
debug("TCP: table compaction (spliced=%d): old index %li, new index %li, "
debug("TCP: table compaction (%s): old index %li, new index %li, "
"from: %p, to: %p",
from->c.spliced, CONN_IDX(from), CONN_IDX(hole),
FLOW_TYPE(&from->f), CONN_IDX(from), CONN_IDX(hole),
(void *)from, (void *)hole);
memset(from, 0, sizeof(*from));
@ -1402,12 +1410,18 @@ void tcp_defer_handler(struct ctx *c)
tcp_l2_data_buf_flush(c);
for (conn = tc + c->tcp.conn_count - 1; conn >= tc; conn--) {
if (conn->c.spliced) {
if (conn->splice.flags & CLOSING)
tcp_splice_destroy(c, conn);
} else {
switch (conn->f.type) {
case FLOW_TCP:
if (conn->tap.events == CLOSED)
tcp_conn_destroy(c, conn);
break;
case FLOW_TCP_SPLICE:
if (conn->splice.flags & CLOSING)
tcp_splice_destroy(c, conn);
break;
default:
die("Unexpected %s in tcp_defer_handler()",
FLOW_TYPE(&conn->f));
}
}
}
@ -2016,7 +2030,7 @@ static void tcp_conn_from_tap(struct ctx *c,
}
conn = CONN(c->tcp.conn_count++);
conn->c.spliced = false;
conn->f.type = FLOW_TCP;
conn->sock = s;
conn->timer = -1;
conn_event(c, conn, TAP_SYN_RCVD);
@ -2726,7 +2740,7 @@ static void tcp_tap_conn_from_sock(struct ctx *c,
const struct sockaddr *sa,
const struct timespec *now)
{
conn->c.spliced = false;
conn->f.type = FLOW_TCP;
conn->sock = s;
conn->timer = -1;
conn->ws_to_tap = conn->ws_from_tap = 0;
@ -2909,10 +2923,17 @@ void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events)
{
union tcp_conn *conn = tc + ref.tcp.index;
if (conn->c.spliced)
tcp_splice_sock_handler(c, &conn->splice, ref.fd, events);
else
switch (conn->f.type) {
case FLOW_TCP:
tcp_tap_sock_handler(c, &conn->tap, events);
break;
case FLOW_TCP_SPLICE:
tcp_splice_sock_handler(c, &conn->splice, ref.fd, events);
break;
default:
die("Unexpected %s in tcp_sock_handler_compact()",
FLOW_TYPE(&conn->f));
}
}
/**
@ -3244,11 +3265,17 @@ void tcp_timer(struct ctx *c, const struct timespec *ts)
}
for (conn = tc + c->tcp.conn_count - 1; conn >= tc; conn--) {
if (conn->c.spliced) {
tcp_splice_timer(c, conn);
} else {
switch (conn->f.type) {
case FLOW_TCP:
if (conn->tap.events == CLOSED)
tcp_conn_destroy(c, conn);
break;
case FLOW_TCP_SPLICE:
tcp_splice_timer(c, conn);
break;
default:
die("Unexpected %s in tcp_timer()",
FLOW_TYPE(&conn->f));
}
}

24
tcp_conn.h
View file

@ -9,19 +9,9 @@
#ifndef TCP_CONN_H
#define TCP_CONN_H
/**
* struct tcp_conn_common - Common fields for spliced and non-spliced
* @spliced: Is this a spliced connection?
*/
struct tcp_conn_common {
bool spliced :1;
};
extern const char *tcp_common_flag_str[];
/**
* struct tcp_tap_conn - Descriptor for a TCP connection (not spliced)
* @c: Fields common with tcp_splice_conn
* @f: Generic flow information
* @in_epoll: Is the connection in the epoll set?
* @next_index: Connection index of next item in hash chain, -1 for none
* @tap_mss: MSS advertised by tap/guest, rounded to 2 ^ TCP_MSS_BITS
@ -46,8 +36,8 @@ extern const char *tcp_common_flag_str[];
* @seq_init_from_tap: Initial sequence number from tap
*/
struct tcp_tap_conn {
/* Must be first element to match tcp_splice_conn */
struct tcp_conn_common c;
/* Must be first element */
struct flow_common f;
bool in_epoll :1;
int next_index :TCP_CONN_INDEX_BITS + 2;
@ -121,7 +111,7 @@ struct tcp_tap_conn {
#define SIDES 2
/**
* struct tcp_splice_conn - Descriptor for a spliced TCP connection
* @c: Fields common with tcp_tap_conn
* @f: Generic flow information
* @in_epoll: Is the connection in the epoll set?
* @s: File descriptor for sockets
* @pipe: File descriptors for pipes
@ -131,8 +121,8 @@ struct tcp_tap_conn {
* @written: Bytes written (not fully written from one other side read)
*/
struct tcp_splice_conn {
/* Must be first element to match tcp_tap_conn */
struct tcp_conn_common c;
/* Must be first element */
struct flow_common f;
bool in_epoll :1;
int s[SIDES];
@ -168,7 +158,7 @@ struct tcp_splice_conn {
* @splice: Fields specific to spliced connections
*/
union tcp_conn {
struct tcp_conn_common c;
struct flow_common f;
struct tcp_tap_conn tap;
struct tcp_splice_conn splice;
};

3
tcp_splice.c
View file

@ -54,6 +54,7 @@
#include "tcp_splice.h"
#include "siphash.h"
#include "inany.h"
#include "flow.h"
#include "tcp_conn.h"
@ -476,7 +477,7 @@ bool tcp_splice_conn_from_sock(const struct ctx *c,
if (setsockopt(s, SOL_TCP, TCP_QUICKACK, &((int){ 1 }), sizeof(int)))
trace("TCP (spliced): failed to set TCP_QUICKACK on %i", s);
conn->c.spliced = true;
conn->f.type = FLOW_TCP_SPLICE;
conn->s[0] = s;
if (tcp_splice_new(c, conn, ref.port, ref.pif))