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Commit Graph

1768 Commits

Author SHA1 Message Date
David Gibson
0804fdbc28 udp: Correctly look up outbound socket with port remappings
Commit bb9bf0bb ("tcp, udp: Don't precompute port remappings in epoll
references") changed the epoll reference for UDP sockets to include the
bound port as seen by the socket itself, rather than the bound port it
would be translated to on the guest side.  As a side effect, it also means
that udp_tap_map[] is indexed by the bound port on the host side, rather
than on the guest side.  This is consistent and a good idea, however we
forgot to account for it when finding the correct outgoing socket for
packets originating in the guest.  This means that if forwarding UDP
inbound with a port number change, reply packets would be misdirected.

Fix this by applying the reverse mapping before looking up the socket in
udp_tap_handler().  While we're at it, use 'port' directly instead of
'uref.port' in udp_sock_init().  Those now always have the same value -
failing to realise that is the same error as above.

Reported-by: Laurent Jacquot <jk@lutty.net>
Link: https://bugs.passt.top/show_bug.cgi?id=87
Fixes: bb9bf0bb8f ("tcp, udp: Don't precompute port remappings in epoll references")
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-04-25 00:00:34 +02:00
Laurent Vivier
95601237ef tcp: Replace TCP buffer structure by an iovec array
To be able to provide pointers to TCP headers and IP headers without
worrying about alignment in the structure, split the structure into
several arrays and point to each part of the frame using an iovec array.

Using iovec also allows us to simply ignore the first entry when the
vnet length header is not needed.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-04-19 11:21:09 +02:00
Stefano Brivio
27f1c762b1 conf: Don't fail if the template interface doesn't have a MAC address
...simply resort to using locally-administered address (LAA) as
host-side source, instead.

Pick 02:00:00:00:00:00, to make it clear that we don't actually care
about that address, and also to match the 00 (Administratively
Assigned Identifier) quadrant of SLAP (RFC 8948).

Otherwise, pasta refuses to start if the template is a tun or
Wireguard interface.

Link: https://bugs.passt.top/show_bug.cgi?id=49
Link: https://github.com/containers/podman/issues/22320
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-04-19 11:21:00 +02:00
Stefano Brivio
eca8baa028 conf: We're interested in the MAC address, not in the MAC itself
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2024-04-19 11:15:36 +02:00
Stefano Brivio
ee338a256e pasta, util: Align stack area for clones to maximum natural alignment
Given that we use this stack pointer as a location to store arbitrary
data types from the cloned process, we need to guarantee that its
alignment matches any of those possible data types.

runsisi reports that pasta gets a SIGBUS in pasta_open_ns() on
aarch64, where the alignment requirement for stack pointers is a
16 bytes (same as the size of a long double), and similar requirements
actually apply to most architectures we run on.

Reported-by: runsisi <runsisi@hust.edu.cn>
Link: https://bugs.passt.top/show_bug.cgi?id=85
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2024-04-19 11:15:27 +02:00
Stefano Brivio
5d5208b67d treewide: Compilers' name for armv6l and armv7l is "arm"
When I switched from 'uname -m' to 'gcc -dumpmachine' to fetch the
architecture name for, among others, seccomp.sh, I didn't realise
that "armv6l" and "armv7l" are just Linux kernel names -- compilers
just call that "arm".

Fix the "syscalls" annotation we use to define seccomp profiles
accordingly, otherwise pasta will be terminated on sigreturn() on
armv6l and armv7l.

Fixes: 213c397492 ("passt, pasta: Run-time selection of AVX2 build")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-04-11 17:34:04 +02:00
David Gibson
954589b64b test: Verify that podman tests are using the pasta binary we expect
Paul Holzinger pointed out that when we invoke the podman tests inside the
passt testsuite, the way we point podman at the newly built pasta binary
is kind of indirect.  It's therefore prudent to check that podman is
actually using the binary we expect it to - in particular that it is using
the binary built in this tree, not some system installed pasta binary.

Suggested-by: Paul Holzinger <pholzing@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-04-05 16:59:24 +02:00
David Gibson
489b28e216 test: catatonit may not be in $PATH
The pasta_podman/bats test script looks for 'catatonit' amongst other tools
to be avaiiliable on the host.  However, while the podman tests do require
catatonit, it doesn't necessarily need to be in the regular path.  For
example Fedora and RHEL place catatonit in /usr/libexec and podman finds it
there fine.

Therefore, remove it as an htools dependency.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-04-05 16:59:21 +02:00
David Gibson
f9fe3ae5dd test: Build and download podman as a test asset
The pasta_podman/bats test scrpt downloads and builds podman, then runs its
pasta specific tests.  Downloading from within a test case has some
drawbacks:
 * It can be very tedious if you have poor connectivity to the server
 * It makes a test that's ostensibly for pasta itself dependent on the
   state of the github server
 * It precludes runnning the tests in an isolated network environment

The same concerns largely apply to building podman too, because it's pretty
common for Go builds to download dependencies themselves.  Therefore move
the download and build of podman from the test itself, to the Makefile
where we prepare other test assets.

To avoid cryptic failures if something went wrong with the build, make
running the test dependent on having the built podman binary.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-04-05 16:59:16 +02:00
David Gibson
e8b78217bb test: Make sure to update mbuto repository
We download and use mbuto to build trivial boot images for our VM tests.
However, if mbuto is already cloned, we won't update it to the current
version.  Add some make logic to ensure that we do this.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-04-05 16:59:13 +02:00
David Gibson
ef2cb13b49 cppcheck: Explicitly give files to check
Currently "make cppcheck" invokes cppcheck on ".", so it will check all the
.c and .h files it can find in the source tree.  This isn't ideal, because
it can find files that aren't actually part of the real build, or even
stale files which aren't in git.

More practically, some upcoming changes are looking at downloading other
source trees for some tests.  Static errors in there is Not Our Problem,
so checking them is both slow and pointless.

So, change the Makefile to invoke cppcheck only on the specific source
files that are part of the build.  For some reason in this format the
badBitmaskCheck warnings in seccomp.h which were suppressed by 5beb3472e
("cppcheck: Avoid errors due to zeroes in bitwise ORs") no longer trigger.
That means we get unmatchedSuppression warnings instead.  We add an
unmatchedSuppression suppression instead of simply removing the original
suppressions, just in case this odd behaviour isn't the same for all
cppcheck versions.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-04-05 16:59:11 +02:00
David Gibson
97e8b33f87 netlink: Ignore routes to link-local addresses for selecting interface
Since f919dc7a4b ("conf, netlink: Don't require a default route to
start"), and since 639fdf06ed ("netlink: Fix selection of template
interface") less buggily, we haven't required a default route on the host
in order to operate.  Instead, if we lack a default route we'll pick an
interface with any route, as long as there's only one such interface.  If
there's more than one, we don't have a good criterion to pick, so we give
up with an informational message.

Paul Holzinger pointed out that this code considers it ambiguous even if
all but one of the interfaces has only routes to link-local addresses
(fe80::/10).  A route to link-local addresses isn't really useful from
pasta's point of view, so ignore them instead.  This removes a misleading
message in many cases, and a spurious failure in some cases.

Suggested-by: Paul Holzinger <pholzing@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-04-05 16:59:08 +02:00
David Gibson
67a6258918 util: Add helper to return name of address family
We have a few places where we want to include the name of the internet
protocol version (IPv4 or IPv6) in a message, which we handle with an
open-coded ?: expression.

This seems like something that might be more widely useful, so make a
trivial helper to return the correct string based on the address family.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-04-05 16:59:05 +02:00
Stefano Brivio
f4e38b5cd2 netlink: Adjust interface index inside copied nexthop objects too
As pasta duplicates host routes into the target namespaces, interface
indices might not match, so we go through RTA_OIF attributes and fix
them up to match the identifier in the namespace.

But RTA_OIF is not the ony attribute specifying interfaces for routes:
multipath routes use RTA_MULTIPATH attributes with nexthop objects,
which contain in turn interface indices. Fix them up as well.

If we don't, and we have at least two host interfaces, and the host
interface we use as template isn't the first one (hence the
mismatching indices), we'll fail to insert multipath routes with
nexthop objects, and ultimately refuse to start as the kernel
unexpectedly gives us ENODEV.

Link: https://github.com/containers/podman/issues/22192
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2024-04-05 16:58:52 +02:00
Danish Prakash
88c2f08eba apparmor: Fix access to procfs namespace entries in pasta's abstraction
From an original patch by Danish Prakash.

With commit ff22a78d7b ("pasta: Don't try to watch namespaces in
procfs with inotify, use timer instead"), if a filesystem-bound
target namespace is passed on the command line, we'll grab a handle
on its parent directory. That commit, however, didn't introduce a
matching AppArmor rule. Add it here.

To access a network namespace procfs entry, we also need a 'ptrace'
rule. See commit 594dce66d3 ("isolation: keep CAP_SYS_PTRACE when
required") for details as to when we need this -- essentially, it's
about operation with Buildah.

Reported-by: Jörg Sonnenberger <joerg@bec.de>
Link: https://github.com/containers/buildah/issues/5440
Link: https://bugzilla.suse.com/show_bug.cgi?id=1221840
Fixes: ff22a78d7b ("pasta: Don't try to watch namespaces in procfs with inotify, use timer instead")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-04-05 12:12:26 +02:00
Stefano Brivio
100919ce74 apparmor: Expand scope of @{run}/user access, allow writing PID files too
With Podman's custom networks, pasta will typically need to open the
target network namespace at /run/user/<UID>/containers/networks:
grant access to anything under /run/user/<UID> instead of limiting it
to some subpath.

Note that in this case, Podman will need pasta to write out a PID
file, so we need write access, for similar locations, too.

Reported-by: Jörg Sonnenberger <joerg@bec.de>
Link: https://github.com/containers/buildah/issues/5440
Link: https://bugzilla.suse.com/show_bug.cgi?id=1221840
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-04-05 12:12:26 +02:00
Stefano Brivio
dc7b7f28b7 apparmor: Add mount rule with explicit, empty source in passt abstraction
For the policy to work as expected across either AppArmor commit
9d3f8c6cc05d ("parser: fix parsing of source as mount point for
propagation type flags") and commit 300889c3a4b7 ("parser: fix option
flag processing for single conditional rules"), we need one mount
rule with matching mount options as "source" (that is, without
source), and one without mount options and an explicit, empty source.

Link: https://github.com/containers/buildah/issues/5440
Link: https://bugzilla.suse.com/show_bug.cgi?id=1221840
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-04-05 12:12:26 +02:00
Stefano Brivio
bbea2752f6 README.md: Alpine, Guix and OpenSUSE now have packages for passt
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2024-04-05 12:12:23 +02:00
David Gibson
4988e2b406 tcp: Unconditionally force ACK for all !SYN, !RST packets
Currently we set ACK on flags packets only when the acknowledged byte
pointer has advanced, or we hadn't previously set a window.  This means
in particular that we can send a window update with no ACK flag, which
doesn't appear to be correct.  RFC 9293 requires a receiver to ignore such
a packet [0], and indeed it appears that every non-SYN, non-RST packet
should have the ACK flag.

The reason for the existing logic, rather than always forcing an ACK seems
to be to avoid having the packet mistaken as a duplicate ACK which might
trigger a fast retransmit.  However, earlier tests in the function mean we
won't reach here if we don't have either an advance in the ack pointer -
which will already set the ACK flag, or a window update - which shouldn't
trigger a fast retransmit.

[0] https://www.ietf.org/rfc/rfc9293.html#section-3.10.7.4-2.5.2.1

Link: https://github.com/containers/podman/issues/22146
Link: https://bugs.passt.top/show_bug.cgi?id=84
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-26 09:52:04 +01:00
David Gibson
5894a245b9 tcp: Never automatically add the ACK flag to RST packets
tcp_send_flag() will sometimes force on the ACK flag for all !SYN packets.
This doesn't make sense for RST packets, where plain RST and RST+ACK have
somewhat different meanings.  AIUI, RST+ACK indicates an abrupt end to
a connection, but acknowledges data already sent.  Plain RST indicates an
abort, when one end receives a packet that doesn't seem to make sense in
the context of what it knows about the connection.  All of the cases where
we send RSTs are the second, so we don't want an ACK flag, but we currently
could add one anyway.

Change that, so we won't add an ACK to an RST unless the caller explicitly
requests it.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-26 09:51:58 +01:00
David Gibson
16c2d8da0d tcp: Rearrange logic for setting ACK flag in tcp_send_flag()
We have different paths for controlling the ACK flag for the SYN and !SYN
paths.  This amounts to sometimes forcing on the ACK flag in the !SYN path
regardless of options.  We can rearrange things to explicitly be that which
will make things neater for some future changes.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-26 09:51:55 +01:00
David Gibson
99355e25b9 tcp: Split handling of DUP_ACK from ACK
The DUP_ACK flag to tcp_send_flag() has two effects: first it forces the
setting of the ACK flag in the packet, even if we otherwise wouldn't.
Secondly, it causes a duplicate of the flags packet to be sent immediately
after the first.

Setting the ACK flag to tcp_send_flag() also has the first effect, so
instead of having DUP_ACK also do that, pass both flags when we need both
operations.  This slightly simplifies the logic of tcp_send_flag() in a way
that makes some future changes easier.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-26 09:51:41 +01:00
Laurent Vivier
71dd405460 util: fix confusion between offset in the iovec array and in the entry
In write_remainder() 'skip' is the offset to start the operation from
in the iovec array.

In iov_skip_bytes(), 'skip' is also the offset in the iovec array but
'offset' is the first unskipped byte in the iovec entry.

As write_remainder() uses 'skip' for both, 'skip' is reset to the
first unskipped byte in the iovec entry rather to staying the first
unskipped byte in the iovec array.

Fix the problem by introducing a new variable not to overwrite 'skip'
on each loop.

Fixes: 8bdb0883b4 ("util: Add write_remainder() helper")
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-20 10:06:32 +01:00
David Gibson
639fdf06ed netlink: Fix selection of template interface
Since f919dc7a4b ("conf, netlink: Don't require a default route to
start"), if there is only one host interface with routes, we will pick that
as the template interface, even if there are no default routes for an IP
version.  Unfortunately this selection had a serious flaw: in some cases
it would 'return' in the middle of an nl_foreach() loop, meaning we
wouldn't consume all the netlink responses for our query.  This could cause
later netlink operations to fail as we read leftover responses from the
aborted query.

Rewrite the interface detection to avoid this problem.  While we're there:
  * Perform detection of both default and non-default routes in a single
    pass, avoiding an ugly goto
  * Give more detail on error and working but unusual paths about the
    situation (no suitable interface, multiple possible candidates, etc.).

Fixes: f919dc7a4b ("conf, netlink: Don't require a default route to start")
Link: https://bugs.passt.top/show_bug.cgi?id=83
Link: https://github.com/containers/podman/issues/22052
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2270257
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[sbrivio: Use info(), not warn() for somewhat expected cases where one
 IP version has no default routes, or no routes at all]
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-20 09:34:08 +01:00
David Gibson
d35bcbee90 netlink: Fix handling of NLMSG_DONE in nl_route_dup()
A recent kernel change 87d381973e49 ("genetlink: fit NLMSG_DONE into
same read() as families") changed netlink behaviour so that the
NLMSG_DONE terminating a bunch of responses can go in the same
datagram as those responses, rather than in a separate one.

Our netlink code is supposed to handle that behaviour, and indeed does
so for most cases, using the nl_foreach() macro.  However, there was a
subtle error in nl_route_dup() which doesn't work with this change.
f00b1534 ("netlink: Don't try to get further datagrams in
nl_route_dup() on NLMSG_DONE") attempted to fix this, but has its own
subtle error.

The problem arises because nl_route_dup(), unlike other cases doesn't
just make a single pass through all the responses to a netlink
request.  It needs to get all the routes, then make multiple passes
through them.  We don't really have anywhere to buffer multiple
datagrams, so we only support the case where all the routes fit in a
single datagram - but we need to fail gracefully when that's not the
case.

After receiving the first datagram of responses (with nl_next()) we
have a first loop scanning them.  It needs to exit when either we run
out of messages in the datagram (!NLMSG_OK()) or when we get a message
indicating the last response (nl_status() <= 0).

What we do after the loop depends on which exit case we had.  If we
saw the last response, we're done, but otherwise we need to receive
more datagrams to discard the rest of the responses.

We attempt to check for that second case by re-checking NLMSG_OK(nh,
status).  However in the got-last-response case, we've altered status
from the number of remaining bytes to the error code (usually 0). That
means NLMSG_OK() now returns false even if it didn't during the loop
check.  To fix this we need separate variables for the number of bytes
left and the final status code.

We also checked status after the loop, but this was redundant: we can
only exit the loop with NLMSG_OK() == true if status <= 0.

Reported-by: Martin Pitt <mpitt@redhat.com>
Fixes: f00b153414 ("netlink: Don't try to get further datagrams in nl_route_dup() on NLMSG_DONE")
Fixes: 4d6e9d0816 ("netlink: Always process all responses to a netlink request")
Link: https://github.com/containers/podman/issues/22052
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-19 10:23:34 +01:00
Dan Čermák
615d370ca2 fedora: Switch license identifier to SPDX
The spec file patch by Dan Čermák was originally contributed at:
  https://src.fedoraproject.org/rpms/passt/pull-request/1

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2024-03-18 08:57:47 +01:00
Stefano Brivio
d989eae308 udp: Translate source address of resolver only for DNS remapped queries
Paul reports that if pasta is configured with --dns-forward, and the
container queries a resolver which is configured on the host directly,
without using the address given for --dns-forward, we'll translate
the source address of the response pretending it's coming from the
address passed as --dns-forward, and the client will discard the
reply.

That is,

  $ cat /etc/resolv.conf
  198.51.100.1
  $ pasta --config-net --dns-forward 192.0.2.1 nslookup passt.top

will not work, because we change the source address of the reply from
198.51.100.1 to 192.0.2.1. But the client contacted 198.51.100.1, and
it's from that address that it expects an answer.

Add a PORT_DNS_FWD flag for tap-facing ports, which is triggered by
activity in the opposite direction as the other flags. If the
tap-facing port was seen sending a DNS query that was remapped, we'll
remap the source address of the response, otherwise we'll leave it
unaffected.

Reported-by: Paul Holzinger <pholzing@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2024-03-18 08:57:40 +01:00
Stefano Brivio
f919dc7a4b conf, netlink: Don't require a default route to start
There might be isolated testing environments where default routes and
global connectivity are not needed, a single interface has all
non-loopback addresses and routes, and still passt and pasta are
expected to work.

In this case, it's pretty obvious what our upstream interface should
be, so go ahead and select the only interface with at least one
route, disabling DHCP and implying --no-map-gw as the documentation
already states.

If there are multiple interfaces with routes, though, refuse to start,
because at that point it's really not clear what we should do.

Reported-by: Martin Pitt <mpitt@redhat.com>
Link: https://github.com/containers/podman/issues/21896
Signed-off-by: Stefano brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2024-03-18 08:57:21 +01:00
Stefano Brivio
f00b153414 netlink: Don't try to get further datagrams in nl_route_dup() on NLMSG_DONE
Martin reports that, with Fedora Linux kernel version
kernel-core-6.9.0-0.rc0.20240313gitb0546776ad3f.4.fc41.x86_64,
including commit 87d381973e49 ("genetlink: fit NLMSG_DONE into same
read() as families"), pasta doesn't exit once the network namespace
is gone.

Actually, pasta is completely non-functional, at least with default
options, because nl_route_dup(), which duplicates routes from the
parent namespace into the target namespace at start-up, is stuck on
a second receive operation for RTM_GETROUTE.

However, with that commit, the kernel is now able to fit the whole
response, including the NLMSG_DONE message, into a single datagram,
so no further messages will be received.

It turns out that commit 4d6e9d0816 ("netlink: Always process all
responses to a netlink request") accidentally relied on the fact that
we would always get at least two datagrams as a response to
RTM_GETROUTE.

That is, the test to check if we expect another datagram, is based
on the 'status' variable, which is 0 if we just parsed NLMSG_DONE,
but we'll also expect another datagram if NLMSG_OK on the last
message is false. But NLMSG_OK with a zero length is always false.

The problem is that we don't distinguish if status is zero because
we got a NLMSG_DONE message, or because we processed all the
available datagram bytes.

Introduce an explicit check on NLMSG_DONE. We should probably
refactor this slightly, for example by introducing a special return
code from nl_status(), but this is probably the least invasive fix
for the issue at hand.

Reported-by: Martin Pitt <mpitt@redhat.com>
Link: https://github.com/containers/podman/issues/22052
Fixes: 4d6e9d0816 ("netlink: Always process all responses to a netlink request")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Tested-by: Paul Holzinger <pholzing@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2024-03-18 08:56:32 +01:00
David Gibson
d3eb0d7b59 tap: Rename tap_iov_{base,len}
These two functions are typically used to calculate values to go into the
iov_base and iov_len fields of a struct iovec.  They don't have to be used
for that, though.  Rename them in terms of what they actually do: calculate
the base address and total length of the complete frame, including both L2
and tap specific headers.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-14 16:57:43 +01:00
David Gibson
4db947d17c tap: Implement tap_send() "slow path" in terms of fast path
Most times we send frames to the guest it goes via tap_send_frames().
However "slow path" protocols - ARP, ICMP, ICMPv6, DHCP and DHCPv6 - go
via tap_send().

As well as being a semantic duplication, tap_send() contains at least one
serious problem: it doesn't properly handle short sends, which can be fatal
on the qemu socket connection, since frame boundaries will get out of sync.

Rewrite tap_send() to call tap_send_frames().  While we're there, rename it
tap_send_single() for clarity.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-14 16:57:37 +01:00
David Gibson
1ebe787fe4 tap: Simplify some casts in the tap "slow path" functions
We can both remove some variables which differ from others only in type,
and slightly improve type safety.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-14 16:57:33 +01:00
David Gibson
2d0e0084b6 tap: Extend tap_send_frames() to allow multi-buffer frames
tap_send_frames() takes a vector of buffers and requires exactly one frame
per buffer.  We have future plans where we want to have multiple buffers
per frame in some circumstances, so extend tap_send_frames() to take the
number of buffers per frame as a parameter.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[sbrivio: Improve comment to rembufs calculation]
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-14 16:57:28 +01:00
Stefano Brivio
f67238aa86 passt, log: Call __openlog() earlier, log to stderr until we detach
Paul reports that, with commit 15001b39ef ("conf: set the log level
much earlier"), early messages aren't reported to standard error
anymore.

The reason is that, once the log mask is changed from LOG_EARLY, we
don't force logging to stderr, and this mechanism was abused to have
early errors on stderr. Now that we drop LOG_EARLY earlier on, this
doesn't work anymore.

Call __openlog() as soon as we know the mode we're running as, using
LOG_PERROR. Then, once we detach, if we're not running from an
interactive terminal and logging to standard error is not forced,
drop LOG_PERROR from the options.

While at it, check if the standard error descriptor refers to a
terminal, instead of checking standard output: if the user redirects
standard output to /dev/null, they might still want to see messages
from standard error.

Further, make sure we don't print messages to standard error reporting
that we couldn't log to the system logger, if we didn't open a
connection yet. That's expected.

Reported-by: Paul Holzinger <pholzing@redhat.com>
Fixes: 15001b39ef ("conf: set the log level much earlier")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2024-03-14 08:19:36 +01:00
Stefano Brivio
3fe9878db7 pcap: Use clock_gettime() instead of gettimeofday()
POSIX.1-2008 declared gettimeofday() as obsolete, but I'm a dinosaur.

Usually, C libraries translate that to the clock_gettime() system
call anyway, but this doesn't happen in Jon's environment, and,
there, seccomp happily kills pasta(1) when started with --pcap,
because we didn't add gettimeofday() to our seccomp profiles.

Use clock_gettime() instead.

Reported-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2024-03-14 08:18:36 +01:00
Stefano Brivio
0761f29a14 passt.1: --{no-,}dhcp-dns and --{no-,}dhcp-search don't take addresses
...they are simple enable/disable options.

Fixes: 89678c5157 ("conf, udp: Introduce basic DNS forwarding")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2024-03-14 08:18:09 +01:00
Stefano Brivio
4d05ba2c58 conf: Warn if we can't advertise any nameserver via DHCP, NDP, or DHCPv6
We might have read from resolv.conf, or from the command line, a
resolver that's reachable via loopback address, but that doesn't mean
we can offer that via DHCP, NDP or DHCPv6: warn if there are no
resolvers we can offer for a given IP version.

Suggested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2024-03-14 08:17:37 +01:00
Stefano Brivio
43881636c2 conf: Handle addresses passed via --dns just like the ones from resolv.conf
...that is, call add_dns4() and add_dns6() instead of simply adding
those to the list of servers we advertise.

Most importantly, this will set the 'dns_host' field for the matching
IP version, so that, as mentioned in the man page, servers passed via
--dns are used for DNS mapping as well, if used in combination with
--dns-forward.

Reported-by: Paul Holzinger <pholzing@redhat.com>
Link: https://bugs.passt.top/show_bug.cgi?id=82
Fixes: 89678c5157 ("conf, udp: Introduce basic DNS forwarding")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Tested-by: Paul Holzinger <pholzing@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2024-03-14 08:16:04 +01:00
Laurent Vivier
b299942bbd tap: Capture only packets that are actually sent
In tap_send_frames(), if we failed to send all the frames, we must
only log the frames that have been sent, not all the frames we wanted
to send.

Fixes: dda7945ca9 ("pcap: Handle short writes in pcap_frame()")
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-13 14:37:27 +01:00
David Gibson
413c15988e udp: Use existing helper for UDP checksum on inbound IPv6 packets
Currently we open code the calculation of the UDP checksum in
udp_update_hdr6().  We calling a helper to handle the IPv6 pseudo-header,
and preset the checksum field to 0 so an uninitialised value doesn't get
folded in.  We already have a helper to do this: csum_udp6() which we use
in some slow paths.  Use it here as well.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-13 14:37:25 +01:00
David Gibson
ae69838db0 udp: Avoid unnecessary pointer in udp_update_hdr4()
We carry around the source address as a pointer to a constant struct
in_addr.  But it's silly to carry around a 4 or 8 byte pointer to a 4 byte
IPv4 address.  Just copy the IPv4 address around by value.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-13 14:37:21 +01:00
David Gibson
b0419d150a udp: Re-order udp_update_hdr[46] for clarity and brevity
The order of things in these functions is a bit odd for historical reasons.
We initialise some IP header fields early, the more later after making
some tests.  Likewise we declare some variables without initialisation,
but then unconditionally set them to values we could calculate at the
start of the function.

Previous cleanups have removed the reasons for some of these choices, so
reorder for clarity, and where possible move the first assignment into an
initialiser.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-13 14:37:19 +01:00
David Gibson
8a842e03cd udp: Pass data length explicitly to to udp_update_hdr[46]
These functions take an index to the L2 buffer whose header information to
update.  They use that for two things: to locate the buffer pointer itself,
and to retrieve the length of the received message from the paralllel
udp[46]_l2_mh_sock array.  The latter is arguably a failure to separate
concerns.  Change these functions to explicitly take a buffer pointer and
payload length as parameters.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-13 14:37:17 +01:00
David Gibson
76571ae869 udp: Consistent port variable names in udp_update_hdr[46]
In these functions we have 'dstport' for the destination port, but
'src_port' for the source port.  Change the latter to 'srcport' for
consistency.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-13 14:37:15 +01:00
David Gibson
205b140dec udp: Refactor udp_sock[46]_iov_init()
Each of these functions have 3 essentially identical loops in a row.
Merge the loops into a single common udp_sock_iov_init() function, calling
udp_sock[46]_iov_init_one() helpers to initialize each "slot" in the
various parallel arrays.  This is slightly neater now, and more naturally
allows changes we want to make where more initialization will become common
between IPv4 and IPv6.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-13 14:36:59 +01:00
Stefano Brivio
860d2764dd conf: Don't warn if nameservers were found, but won't be advertised
Starting from commit 3a2afde87d ("conf, udp: Drop mostly duplicated
dns_send arrays, rename related fields"), we won't add to c->ip4.dns
and c->ip6.dns nameservers that can't be used by the guest or
container, and we won't advertise them.

However, the fact that we don't advertise any nameserver doesn't mean
that we didn't find any, and we should warn only if we couldn't find
any.

This is particularly relevant in case both --dns-forward and
--no-map-gw are passed, and a single loopback address is listed in
/etc/resolv.conf: we'll forward queries directed to the address
specified by --dns-forward to the loopback address we found, we
won't advertise that address, so we shouldn't warn: this is a
perfectly legitimate usage.

Reported-by: Paul Holzinger <pholzing@redhat.com>
Link: https://github.com/containers/podman/issues/19213
Fixes: 3a2afde87d ("conf, udp: Drop mostly duplicated dns_send arrays, rename related fields")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Tested-by: Paul Holzinger <pholzing@redhat.com>
2024-03-12 01:50:48 +01:00
David Gibson
4779dfe12f icmp: Use 'flowside' epoll references for ping sockets
Currently ping sockets use a custom epoll reference type which includes
the ICMP id.  However, now that we have entries in the flow table for
ping flows, finding that is sufficient to get everything else we want,
including the id.  Therefore remove the icmp_epoll_ref type and use the
general 'flowside' field for ping sockets.

Having done this we no longer need separate EPOLL_TYPE_ICMP and
EPOLL_TYPE_ICMPV6 reference types, because we can easily determine
which case we have from the flow type. Merge both types into
EPOLL_TYPE_PING.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-12 01:49:05 +01:00
David Gibson
02cbdb0b86 icmp: Flow based error reporting
Use flow_dbg() and flow_err() helpers to generate flow-linked error
messages in most places.  Make a few small improvements to the messages
while we're at it.  This allows us to avoid the awkward 'pname' variables
since whether we're dealing with ICMP or ICMPv6 is already built into the
flow type which these helpers include.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[sbrivio: Coding style fix in icmp_tap_handler()]
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-12 01:36:04 +01:00
David Gibson
3af5e9fdba icmp: Store ping socket information in flow table
Currently icmp_id_map[][] stores information about ping sockets in a
bespoke structure.  Move the same information into new types of flow
in the flow table.  To match that change, replace the existing ICMP
timer with a flow-based timer for expiring ping sockets.  This has the
advantage that we only need to scan the active flows, not all possible
ids.

We convert icmp_id_map[][] to point to the flow table entries, rather
than containing its own information.  We do still use that array for
locating the right ping flows, rather than using a "flow native" form
of lookup for the time being.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[sbrivio: Update id_sock description in comment to icmp_ping_new()]
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2024-03-12 01:34:45 +01:00
Stefano Brivio
383a6f67e5 ip: Use regular htons() for non-constant protocol number in L2_BUF_IP4_PSUM
instead of htons_constant(), which is for... constants.

Fixes: 5bf200ae8a ("tcp, udp: Don't include destination address in partially precomputed csums")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2024-03-08 10:31:14 +01:00