passt, branch 2022_10_26.f212044

icmp: Don't discard first reply sequence for a given echo ID

2022-10-26T22:18:21+00:00

In pasta mode, ICMP and ICMPv6 echo sockets relay back to us any
reply we send: we're on the same host as the target, after all. We
discard them by comparing the last sequence we sent with the sequence
we receive.

However, on the first reply for a given identifier, the sequence
might be zero, depending on the implementation of ping(8): we need
another value to indicate we haven't sent any sequence number, yet.

Use -1 as initialiser in the echo identifier map.

This is visible with Busybox's ping, and was reported by Paul on the
integration at https://github.com/containers/podman/pull/16141, with:

  $ podman run --net=pasta alpine ping -c 2 192.168.188.1

...where only the second reply would be routed back.

Reported-by: Paul Holzinger 
Fixes: 33482d5bf293 ("passt: Add PASTA mode, major rework")
Signed-off-by: Stefano Brivio 
Reviewed-by: David Gibson

icmp: Add debugging messages for handled replies and requests

2022-10-26T22:18:18+00:00

...instead of just reporting errors.

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

tap: Trace received (outbound) ICMP packets in debug mode, too

2022-10-26T22:18:16+00:00

This only worked for ICMPv6: ICMP packets have no TCP-style header,
so they are handled as a special case before packet sequences are
formed, and the call to tap_packet_debug() was missing.

Fixes: bb708111833e ("treewide: Packet abstraction with mandatory boundary checks")
Signed-off-by: Stefano Brivio 
Reviewed-by: David Gibson

conf, passt.1: Don't imply --foreground with --debug

2022-10-26T22:17:56+00:00

Having -f implied by -d (and --trace) usually saves some typing, but
debug mode in background (with a log file) is quite useful if pasta
is started by Podman, and is probably going to be handy for passt
with libvirt later, too.

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

test/run: Temporarily disable distribution tests

2022-10-26T05:03:56+00:00

They're too slow to cope with current release cycles, and they
haven't found bugs in months, also because clang-tidy and cppcheck
would find most of them earlier.

Disable them for the moment. We should pre-install gcc and make in
non-x86 images, as those run on my test machine with qemu TCG, and
that's the real slow-down here. Then we can re-enable them.

Signed-off-by: Stefano Brivio

hooks: Temporarily disable demo generation in pre-push

2022-10-26T04:56:25+00:00

The out-of-tree Podman patch needs to be rebased every second week or
so, and I'm currently trying to get that upstream:
  https://github.com/containers/podman/pull/16141

Disable demo generation for the moment, so that I avoid wasting time
with those rebases. We'll re-enable it later.

Signed-off-by: Stefano Brivio

test: Add log file tests for pasta plus corresponding layout and setup

2022-10-26T04:28:41+00:00

To test log files on a tmpfs mount, we need to unshare the mount
namespace, which means using a context for the passt pane is not
really practical at the moment, as we can't open a shell there, so
we would have to encapsulate all the commands under 'unshare -rUm',
plus the "inner" pasta command, running in turn a tcp_rr server.

It might be worth fixing this by e.g. detecting we are trying to
spawn an interactive shell and adding a special path in the context
setup with some form of stdin redirection -- I'm not sure it's doable
though.

For this reason, add a new layout, using a context only for the host
pane, while keeping the old command dispatch mechanism for the passt
pane.

We also need a new setup function that doesn't start pasta: we want
to start and restart it with different options.

Further, we need a 'pint' directive, to send an interrupt to the
passt pane: add that in lib/test.

All the tests before the one involving tmpfs and a detached mount
namespace were also tested with the context mechanism. To make an
eventual conversion easier, pass tcp_crr directly as a command on
pasta's command line where feasible.

While at it, fix the comment to the teardown_pasta() function.

The new test set can be semi-conveniently run as:

  ./run pasta_options/log_to_file

and it checks basic log creation, size of the log file after flooding
it with debug entries, rotations, and basic consistency after
rotations, on both an existing filesystem and a tmpfs, chosen as
it doesn't support collapsing data ranges via fallocate(), hence
triggering the fall-back mechanism for logging rotation.

Signed-off-by: Stefano Brivio

checksum: Fix calculation for ICMP checksum on IPv4

2022-10-26T04:28:06+00:00

We need to zero out the checksum field before calculating the
checksum, of course. I have no idea how this passed the "icmp" test
set, looking into it.

Reported-by: Paul Holzinger 
Fixes: 67ab6171729c ("Add csum_icmp4() helper for calculating ICMP checksums")
Signed-off-by: Stefano Brivio 
Reviewed-by: David Gibson

conf: Don't pass leading ~ to parse_port_range() on exclusions

2022-10-24T12:37:22+00:00

Commit 84fec4e998b6 ("Clean up parsing of port ranges") drops the
strspn() call before the parsing of excluded port ranges, because now
we're checking against any stray characters at every step.

However, that also has the effect of passing ~ as first character to
the new parse_port_range(), which makes no sense: we already checked
that ~ is the first character before the call, so skip it.

Alona reported this output:
  Invalid port specifier ~15000,~15001,~15006,~15008,~15020,~15021,~15090

while the whole specifier is indeed valid.

Reported-by: Alona Paz 
Fixes: 84fec4e998b6 ("Clean up parsing of port ranges")
Signed-off-by: Stefano Brivio

util: Set NS_FN_STACK_SIZE to one eighth of ulimit-reported maximum stack size

2022-10-22T06:46:57+00:00

...instead of one fourth. On the main() -> conf() -> nl_sock_init()
call path, LTO from gcc 12 on (at least) x86_64 decides to inline...
everything: nl_sock_init() is effectively part of main(), after
commit 3e2eb4337bc0 ("conf: Bind inbound ports with
CAP_NET_BIND_SERVICE before isolate_user()").

This means we exceed the maximum stack size, and we get SIGSEGV,
under any condition, at start time, as reported by Andrea on a recent
build for CentOS Stream 9.

The calculation of NS_FN_STACK_SIZE, which is the stack size we
reserve for clones, was previously obtained by dividing the maximum
stack size by two, to avoid an explicit check on architecture (on
PA-RISC, also known as hppa, the stack grows up, so we point the
clone to the middle of this area), and then further divided by two
to allow for any additional usage in the caller.

Well, if there are essentially no function calls anymore, this is
not enough. Divide it by eight, which is anyway much more than
possibly needed by any clone()d callee.

I think this is robust, so it's a fix in some sense. Strictly
speaking, though, we have no formal guarantees that this isn't
either too little or too much.

What we should do, eventually: check cloned() callees, there are just
thirteen of them at the moment. Note down any stack usage (they are
mostly small helpers), bonus points for an automated way at build
time, quadruple that or so, to allow for extreme clumsiness, and use
as NS_FN_STACK_SIZE. Perhaps introduce a specific condition for hppa.

Reported-by: Andrea Bolognani 
Fixes: 3e2eb4337bc0 ("conf: Bind inbound ports with CAP_NET_BIND_SERVICE before isolate_user()")
Signed-off-by: Stefano Brivio