passt/Makefile, branch 2023_02_27.c538ee8

treewide: Disable gcc strict aliasing rules as needed, drop workarounds

2023-02-27T17:54:13+00:00

Recently, commit 4ddbcb9c0c55 ("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 
Reviewed-by: David Gibson

Makefile: Explict int type in FALLOC_FL_COLLAPSE_RANGE probe

2023-02-14T16:24:16+00:00

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

build: Remove *~ files with make clean

2022-11-25T00:40:21+00:00

These files are left around by emacs amongst other editors.

Signed-off-by: Richard W.M. Jones 
Reviewed-by: David Gibson 
Signed-off-by: Stefano Brivio

build: Force-create pasta symlink

2022-11-25T00:40:00+00:00

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 
Reviewed-by: David Gibson 
Signed-off-by: Stefano Brivio

util: Allow sock_l4() to open dual stack sockets

2022-11-25T00:35:58+00:00

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 
Signed-off-by: Stefano Brivio

inany: Helper functions for handling addresses which could be IPv4 or IPv6

2022-11-25T00:35:32+00:00

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 
Signed-off-by: Stefano Brivio

tcp: Move connection state structures into a shared header

2022-11-25T00:34:43+00:00

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 
Signed-off-by: Stefano Brivio

clang-tidy: Suppress warning about assignments in if statements

2022-11-25T00:34:08+00:00

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 
Signed-off-by: Stefano Brivio

Makefile: Change HPPA into PARISC while building PASST_AUDIT_ARCH

2022-11-16T14:10:46+00:00

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 
Reviewed-by: David Gibson

Makefile: It's AUDIT_ARCH_MIPSEL64, not AUDIT_ARCH_MIPS64EL

2022-11-16T14:10:35+00:00

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 
Reviewed-by: David Gibson