valgrind complains if we pass a NULL buffer to recv(), even if we use
MSG_TRUNC, in which case it's actually safe. For a long time we've had
a valgrind suppression for this. It singles out the recv() in
tcp_sock_consume(), the only place we use MSG_TRUNC.
However, tcp_sock_consume() only has a single caller, which makes it a
prime candidate for inlining. If inlined, it won't appear on the stack and
valgrind won't match the correct suppression.
It appears that certain compiler versions (for example gcc-13.2.1 in
Fedora 39) will inline this function even with the -O0 we use for valgrind
builds. This breaks the suppression leading to a spurious failure in the
tests.
There's not really any way to adjust the suppression itself without making
it overly broad (we don't want to match other recv() calls). So, as a hack
explicitly prevent inlining of this function when we're making a valgrind
build. To accomplish this add an explicit -DVALGRIND when making such a
build.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
clang-tidy from LLVM 17.0.3 (which is in Fedora 39) includes a new
"misc-include-cleaner" warning that tries to make sure that headers
*directly* provide the things that are used in the .c file. That sounds
great in theory but is in practice unusable:
Quite a few common things in the standard library are ultimately provided
by OS-specific system headers, but for portability should be accessed via
closer-to-standardised library headers. This will warn constantly about
such cases: e.g. it will want you to include <linux/limits.h> instead of
<limits.h> to get PATH_MAX.
So, suppress this warning globally in the Makefile.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
logmsg() takes printf like arguments, but because it's not a built in, the
compiler won't generate warnings if the format string and parameters don't
match. Enable those by using the format attribute.
Strictly speaking this is a gcc extension, but I believe it is also
supported by some other common compilers. We already use some other
attributes in various places. For now, just use it and we can worry about
compilers that don't support it if it comes up.
This exposes some warnings from existing callers, both in gcc and in
clang-tidy:
- Some are straight out bugs, which we correct
- It's occasionally useful to invoke the logging functions with an empty
string, which gcc objects to, so disable that specific warning in the
Makefile
- Strictly speaking the C standard requires that the parameter for a %p
be a (void *), not some other pointer type. That's only likely to cause
problems in practice on weird architectures with different sized
representations for pointers to different types. Nonetheless add the
casts to make it happy.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
We have several possible ways of communicating with other entities. We use
sockets to communicate with the host and other network sites, but also in
a different context to communicate "spliced" channels to a namespace. We
also use a tuntap device or a qemu socket to communicate with the namespace
or guest.
For the time being these are just defined implicitly by how we structure
things. However, there are other communication channels we want to use in
future (e.g. virtio-user), and we want to allow more flexible forwarding
between those. To accomplish that we're going to want a specific way of
referring to those channels.
Introduce the concept of a "passt/pasta interface" or "pif" representing a
specific channel to communicate network data. Each pif is assumed to be
associated with a specific network namespace in the broad sense (that is
as a place where IP addresses have a consistent meaning - not the Linux
specific sense). But there could be multiple pifs communicating with the
same namespace (e.g. the spliced and tap interfaces in pasta).
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
The implementation of scanning /proc files to do automatic port forwarding
is a bit awkwardly split between procfs_scan_listen() in util.c,
get_bound_ports() and related functions in conf.c and the initial setup
code in conf().
Consolidate all of this into port_fwd.h, which already has some related
definitions, and a new port_fwd.c.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Recent enough cppcheck versions (at least as of cppcheck 2.12) give this
error processing conf.c:
conf.c:1179:1: information: ValueFlow analysis is limited in conf. Use --check-level=exhaustive if full analysis is wanted. [checkLevelNormal]
Adding --check-level=exhaustive doesn't seem to significantly increase the
cppcheck run time for us, so enable it when possible, suppressing that
warning.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
We have a bunch of variants of the siphash functions for different data
sizes. The callers, in tcp.c, need to pack the various values they want to
hash into a temporary structure, then call the appropriate version. We can
avoid the copy into the temporary by directly using the incremental
siphash functions.
The length specific hash functions also have an undocumented constraint
that the data pointer they take must, in fact, be aligned to avoid
unaligned accesses, which may cause crashes on some architectures.
So, prefer the incremental approach and remove the length-specific
functions.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
We have several workarounds for a clang-tidy bug where the checker doesn't
recognize that a number of system calls write to - and therefore initialise
- a socket address. We can't neatly use a suppression, because the bogus
warning shows up some time after the actual system call, when we access
a field of the socket address which clang-tidy erroneously thinks is
uninitialised.
Consolidate these workarounds into one place by using macros to implement
wrappers around affected system calls which add a memset() of the sockaddr
to silence clang-tidy. This removes the need for the individual memset()
workarounds at the callers - and the somewhat longwinded explanatory
comments.
We can then use a #define to not include the hack in "real" builds, but
only consider it for clang-tidy.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
C11 has some features that will allow us to make some things a bit cleaner.
Alter the Makefile to tell the compiler to allow us to use C11 code.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This reverts commit cc2a6bec3c: I
applied that patch by mistake.
Fixes: cc2a6bec3c ("MAKE: Fix parallel builds; .o files; .gitignore; new makedocs")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
In practical terms, passt doesn't benefit from the additional
protection offered by the AGPL over the GPL, because it's not
suitable to be executed over a computer network.
Further, restricting the distribution under the version 3 of the GPL
wouldn't provide any practical advantage either, as long as the passt
codebase is concerned, and might cause unnecessary compatibility
dilemmas.
Change licensing terms to the GNU General Public License Version 2,
or any later version, with written permission from all current and
past contributors, namely: myself, David Gibson, Laine Stump, Andrea
Bolognani, Paul Holzinger, Richard W.M. Jones, Chris Kuhn, Florian
Weimer, Giuseppe Scrivano, Stefan Hajnoczi, and Vasiliy Ulyanov.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
A cross-architecture build might pass a target-specific CC on 'make',
and not on 'make install', and this is what happens in Debian
cross-qa tests.
Given that we select binaries to be installed depending on the target
architecture, this means we would build AVX2 binaries in any case on
a x86_64 build machine.
By overriding TARGET in package build rules, we can tell the Makefile
about the target architecture, also for the 'install' (Makefile)
target.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Debian cross-building automatic checks:
http://crossqa.debian.net/src/passt
currently fail because we don't use the right target architecture and
compiler while building the system call lists and resolving their
numbers in seccomp.sh. Pass ARCH and CC to seccomp.sh and use them.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Recently, commit 4ddbcb9c0c ("tcp: Disable optimisations
for tcp_hash()") worked around yet another issue we hit with gcc 12
and '-flto -O2': some stores affecting the input data to siphash_20b()
were omitted altogether, and tcp_hash() wouldn't get the correct hash
for incoming connections.
Digging further into this revealed that, at least according to gcc's
interpretation of C99 aliasing rules, passing pointers to functions
with different types compared to the effective type of the object
(for example, a uint8_t pointer to an anonymous struct, as it happens
in tcp_hash()), doesn't guarantee that stores are not reordered
across the function call.
This means that, in general, our checksum and hash functions might
not see parts of input data that was intended to be provided by
callers.
Not even switching from uint8_t to character types, which should be
appropriate here, according to C99 (ISO/IEC 9899, TC3, draft N1256),
section 6.5, "Expressions", paragraph 7:
An object shall have its stored value accessed only by an lvalue
expression that has one of the following types:
[...]
— a character type.
does the trick. I guess this is also subject to interpretation:
casting passed pointers to character types, and then using those as
different types, might still violate (dubious) aliasing rules.
Disable gcc strict aliasing rules for potentially affected functions,
which, in turn, disables gcc's Type-Based Alias Analysis (TBAA)
optimisations based on those function arguments.
Drop the existing workarounds. Also the (seemingly?) bogus
'maybe-uninitialized' warning on the tcp_tap_handler() > tcp_hash() >
siphash_20b() path goes away with -fno-strict-aliasing on
siphash_20b().
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Future compilers will not support implicit ints by default, causing
the probe to always fail.
Link: https://bugs.passt.top/show_bug.cgi?id=42
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
These files are left around by emacs amongst other editors.
Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
If you run the build several times it will fail unnecessarily with:
ln -s passt pasta
ln: failed to create symbolic link 'pasta': File exists
make: *** [Makefile:134: pasta] Error 1
Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Currently, when instructed to open an IPv6 socket, sock_l4() explicitly
sets the IPV6_V6ONLY socket option so that the socket will only respond to
IPv6 connections. Linux (and probably other platforms) allow "dual stack"
sockets: IPv6 sockets which can also accept IPv4 connections.
Extend sock_l4() to be able to make such sockets, by passing AF_UNSPEC as
the address family and no bind address (binding to a specific address would
defeat the purpose). We add a Makefile define 'DUAL_STACK_SOCKETS' to
indicate availability of this feature on the target platform.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
struct tcp_conn stores an address which could be IPv6 or IPv4 using a
union. We can do this without an additional tag by encoding IPv4 addresses
as IPv4-mapped IPv6 addresses.
This approach is useful wider than the specific place in tcp_conn, so
expose a new 'union inany_addr' like this from a new inany.h. Along with
that create a number of helper functions to make working with these "inany"
addresses easier.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Currently spliced and non-spliced connections use completely independent
tracking structures. We want to unify these, so as a preliminary step move
the definitions for both variants into a new tcp_conn.h header, shared by
tcp.c and tcp_splice.c.
This requires renaming some #defines with the same name but different
meanings between the two cases. In the process we correct some places that
are slightly out of sync between the comments and the code for various
event bit names.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
clang-tools 15.0.0 appears to have added a new warning that will always
complain about assignments in if statements, which we use in a number of
places in passt/pasta. Encountered on Fedora 37 with
clang-tools-extra-15.0.0-3.fc37.x86_64.
Suppress the new warning so that we can compile and test.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
The AUDIT_ARCH defines in seccomp.h corresponding to HPPA are
AUDIT_ARCH_PARISC and AUDIT_ARCH_PARISC64.
Build error spotted in Debian's buildd log on
phantom.physik.fu-berlin.de.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
On mips64el, gcc -dumpmachine correctly reports mips64el as
architecture prefix, but for some reason seccomp.h defines
AUDIT_ARCH_MIPSEL64 and not AUDIT_ARCH_MIPS64EL. Mangle AUDIT_ARCH
accordingly.
Build error spotted in Debian's buildd logs from Loongson build.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Drop it from the internal FLAGS variable, but honour -O2 if passed in
CFLAGS. In Debian packages, dpkg-buildflags uses it as hardening
flag, and we get a QA warning if we drop it:
https://qa.debian.org/bls/bytag/W-dpkg-buildflags-missing.html
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
CPPFLAGS allow the user to pass pre-processor flags. This is unlikely
to be needed at the moment, but the Debian Hardening Walkthrough
reasonably requests it to be handled in order to fully support
hardened build flags:
https://wiki.debian.org/HardeningWalkthrough#Handling_dpkg-buildflags_in_your_upstream_build_system
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
In some environments, such as KubeVirt pods, we might not have a
system logger available. We could choose to run in foreground, but
this takes away the convenient synchronisation mechanism derived from
forking to background when interfaces are ready.
Add optional logging to file with -l/--log-file and --log-size.
Unfortunately, this means we need to duplicate features that are more
appropriately implemented by a system logger, such as rotation. Keep
that reasonably simple, by using fallocate() with range collapsing
where supported (Linux kernel >= 3.15, extent-based ext4 and XFS) and
falling back to an unsophisticated block-by-block moving of entries
toward the beginning of the file once we reach the (mandatory) size
limit.
While at it, clarify the role of LOG_EMERG in passt.c.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Logging to file is going to add some further complexity that we don't
want to squeeze into util.c.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
With gcc 11 and 12, passing -flto, or -flto=auto, and -O2,
intra-procedural optimisation gets rid of a fundamental bit in ndp():
the store of hop_limit in the IPv6 header, before the checksum is
calculated, which on x86_64 looks like this:
ip6hr->hop_limit = IPPROTO_ICMPV6;
b8c0: c6 44 24 35 3a movb $0x3a,0x35(%rsp)
Here, hop_limit is temporarily set to the protocol number, to
conveniently get the IPv6 pseudo-header for ICMPv6 checksum
calculation in memory.
With LTO, the assignment just disappears from the binary.
This is rather visible as NDP messages get a wrong checksum, namely
the expected checksum plus 58, and they're ignored by the guest or
in the namespace, meaning we can't get any IPv6 routes, as reported
by Wenli Quan.
The issue affects a significant number of distribution builds,
including the ones for CentOS Stream 9, EPEL 9, Fedora >= 35,
Mageia Cauldron, and openSUSE Tumbleweed.
As a quick workaround, declare csum_unaligned() as "noipa" for gcc
11 and 12, with -flto and -O2. This disables inlining and cloning,
which causes the assignment to be compiled again.
Leave a TODO item: we should figure out if a gcc issue has already
been reported, and report one otherwise. There's no apparent
justification as to why the store could go away.
Reported-by: Wenli Quan <wquan@redhat.com>
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2129713
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Commit 1a563a0cbd ("passt: Address gcc 11 warnings") works around an
issue where the remote address passed to hash functions is seen as
uninitialised by gcc, with -flto and -O2.
It turns out we get the same exact behaviour on gcc 12.1 and 12.2, so
extend the applicability of the same workaround to gcc 12.
Don't go further than that, though: should the issue reported at:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78993
happen to be fixed in a later version of gcc, we won't need the
noinline attributes anymore. Otherwise, we'll notice.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
It's unclear what original suppressions these unmatchedSuppression
suppressions were supposed to go with. They don't trigger any warnings on
the current code that I can tell, so remove them. If we find a problem
with some cppcheck versions in future, replace them with inline
suppressions so it's clearer exactly where the issue is originating.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
We have a couple of functions that are unused (for now) by design.
Although at least one has a flag so that gcc doesn't warn, cppcheck has its
own warnings about this. Add specific inline suppressions for these rather
than a blanket suppression in the Makefile.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
I can't get this warning to trigger, even without the suppression, so
remove it. If it shows up again on some cppcheck version, we can replace
it with inline suppressions so it's clear where the issue lay.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
I can't get these warnings to trigger on the cppcheck versions I have, so
remove them. If we find in future we need to replace these, they should be
replaced with inline suppressions so its clear what's the section of code
at issue.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
I can't get this warning to trigger, so I think this suppression must be
out of date. Whether that's because we've changed our code to no longer
have the problem, or because cppcheck itself has been updated to remove a
false positive I don't know.
If we find that we do need a suppression like this for some cppcheck
version, we should replace it with an inline suppression so it's clear
what exactly is triggering the warning.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
seccomp.sh generates seccomp.h, so if we change it, we should re-build
seccomp.h as well. Add this to the make dependencies so it happens.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Since bf95322f "conf: Make the argument to --pcap option mandatory" we
no longer call localtime() in pcap.c, so we no longer need the matching
cppcheck suppression.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
In a number of places in passt we use structures to represent over the wire
or in-file data with a fixed layout. After initialization we don't access
the fields individually and just write the structure as a whole to its
destination.
Unfortunately cppcheck doesn't cope with this pattern and thinks all the
structure members are unused. We already have suppressions for this in
pcap.c and dhcp.c However, it also appears in dhcp.c and netlink.c at
least. Since this is likely to be common, it seems wiser to just suppress
the error globally.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
strtok() is non-reentrant and old-fashioned, so cppcheck would complains
about its use in conf.c if it weren't suppressed. We're single threaded
and strtok() is convenient though, so it's not really worth reworking at
this time. Convert this to an inline suppression so it's adjacent to the
code its annotating.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
qrap.c uses several old-fashioned functions that cppcheck complains about.
Since it's headed for obselesence anyway, just suppress these rather than
attempting to modernize the code.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
We define our own ffsl() as a weak symbol, in case our C library doesn't
include it. On glibc systems which *do* include it, this causes a cppcheck
warning because unsurprisingly our version doesn't pick the same argument
names. Convert the suppression for this into an inline suppression.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
conf_runas() handles several of the different possible cases for the
--runas argument in a slightly odd order. Although it can parse both
numeric UIDs/GIDs and user/group names, it can't parse a numeric UID
combined with a group name or vice versa. That's not obviously useful, but
it's slightly surprising gap to have.
Rework the parsing to be more systematic: first split the option into
user and (optional) group parts, then separately parse each part as either
numeric or a name. As a bonus this removes some clang-tidy warnings.
While we're there also add cppcheck suppressions for getpwnam() and
getgrnam(). It complains about those because they're not reentrant.
passt is single threaded though, and is always likely to be during
this initialization code, even if we multithread later.
There were some existing suppressions for these in the cppcheck
invocation but they're no longer up to date. Replace them with inline
suppressions which, being next to the code, are more likely to stay
correct.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Debian and similar distros put target specific header files in
/usr/include/<arch-vendor-os>, rather than directly in /usr/include. Add
this directory to the includes for cppcheck so it can find them.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
We do some manipulation of the output of cc -v to get the target triple
for the platform, to locate headers for cppcheck. However, we can get
this more easily with cc -dumpmachine - and in fact we do so elsewhere in
the Makefile.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Adding the --quiet option to cppcheck makes the actual errors and warnings
easier to find.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
make cppcheck takes a long time, because it checks a large number of
different configurations. It's assembling this very large set of
configurations not because of conditionals in the passt code itself,
but from those in the system headers. By adding --config-exclude
directives to stop considering those configs, make cppcheck becomes
around 60x faster on my system.
Similarly, any problems that are found in the system headers are not our
problem, and so we can uniformly suppress them, rather than having specific
suppressions for particular problems in particular files (which might not
be correct for all different distro / version combinations either).
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This check complains about any identifier of less than 3 characters. For
locals and parameters this is often pointlessly verbose. Disable it.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
enum conf_port_type is local to conf.c and is used to track the port
forwarding mode during configuration. We don't keep it around in the
context structure, however the 'init_detect_ports' and 'ns_detect_ports'
fields in the context are based solely on this. Rather than changing
encoding, just include the forwarding mode into the context structure.
Move the type definition to a new port_fwd.h, which is kind of trivial at
the moment but will have more stuff later.
While we're there, "conf_port_type" doesn't really convey that this enum is
describing how port forwarding is configured. Rename it to port_fwd_mode.
The variables (now fields) of this type also have mildly confusing names
since it's not immediately obvious whether 'ns' and 'init' refer to the
source or destination of the packets. Use "in" (host to guest / init to
ns) and "out" (guest to host / ns to init) instead.
This has the added bonus that we no longer have locals 'udp_init' and
'tcp_init' which shadow global functions.
In addition, add a typedef 'port_fwd_map' for a bitmap of each port number,
which is used in several places.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
