This test program verifies that we can receive and discard datagrams by
using recv() with a NULL buffer and zero-length. Extend it to verify it
also works using recvmsg() and either an iov with a zero-length NULL
buffer or an iov that itself is NULL and zero-length.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[sbrivio: Fixed printf() message in main of recv-zero.c]
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
To simplify lifetime management of "listening" UDP sockets, UDP flow
support needs to duplicate existing bound sockets. Those duplicates will
be close()d when their corresponding flow expires, but we expect the
original to still receive datagrams as always. That is, we expect the
close() on the duplicate to remove the duplicated fd, but not to close the
underlying UDP socket.
Add a test program to doc/platform-requirements to verify this requirement.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This test program checks for particular behaviour regardless of order of
operations. So, we step through the test with all possible orders for
a number of different of parts. Or at least, we're supposed to, a copy
pasta error led to using the same order for two things which should be
independent.
Fixes: 299c407501 ("doc: Add program to document and test assumptions about SO_REUSEADDR")
Reported-by: David Taylor <davidt@yadt.co.uk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Add a test program verifying that we're able to discard datagrams from a
socket without needing a big discard buffer, by using a zero length recv().
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
For the approach we intend to use for handling UDP flows, we have some
pretty specific requirements about how SO_REUSEADDR works with UDP sockets.
Specifically SO_REUSEADDR allows multiple sockets with overlapping bind()s,
and therefore there can be multiple sockets which are eligible to receive
the same datagram. Which one will actually receive it is important to us.
Add a test program which verifies things work the way we expect, which
documents what those expectations are in the process.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
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>
ShellCheck reports (SC2034) that __qemu_arch is not used. Use it,
and silence the resulting SC2086 warning as we want word splitting on
options we pass with it.
While at it, silence SC2317 warnings for commands in cleanup() that
appear to be unreachable: cleanup() is only called as trap.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
...and not in pasta's namespace: the fakeroot(1) version shipping
with (at least) Fedora 36 assumes "nested" operation as it sees that
the UID is 0, and claims it's not supported.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
dhclient might be in /usr/sbin on recent versions of Fedora, and
mbuto just adds it to the same location as it was on the host:
just call dhclient instead of /sbin/dhclient.
This also applies for dhclient-script: given that we create the file
on boot, pass its explicit location with -sf.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
The original demo script was written when pasta wasn't a thing yet,
so it needed to run as root, set up a veth pair, and configure
addresses and routes by itself.
Now pasta can do all that for us, and become part of the demo as
well.
Further, extend it to start qemu, optionally preparing a basic demo
image with mbuto (https://mbuto.sh), and execute one logical step at
a time, for clarity.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
ip(8)'s ability to take abbreviated arguments (e.g. "li sh" instead of
"link show") is very handy when using it interactively, but it doesn't make
for very readable scripts and examples when shown that way.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
SPDX tags don't replace license files. Some notices were missing and
some tags were not according to the SPDX specification, too.
Now reuse --lint from the REUSE tool (https://reuse.software/) passes.
Reported-by: Martin Hauke <mardnh@gmx.de>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
...sharing the same filesystem. Instead of a fixed path for the UNIX
domain socket, passt now uses a path with a counter, probing for
existing instances, and picking the first free one.
The demo script is updated accordingly -- it can now be started several
times to create multiple namespaces with an instance of passt each,
with addressing reflecting separate subnets, and NDP proxying between
them.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Otherwise, buffers for UNIX domain sockets are limited to about
200KB. This makes performance testing a bit more consistent.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Default value for /proc/sys/fs/nr_open is 2^20, which is more than
enough: set this hard limit as current (soft) limit on start, and
drop the 'ulimit -n' from the demo script.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
It's nice to be able to confirm connectivity using ICMP or ICMPv6
echo requests, and "ping" sockets on Linux (IPPROTO_ICMP datagram)
allow us to do that without any special capability.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
A bunch of fixes not worth single commits at this stage, notably:
- make buffer, length parameter ordering consistent in ARP, DHCP,
NDP handlers
- strict checking of buffer, message and option length in DHCP
handler (a malicious client could have easily crashed it)
- set up forwarding for IPv4 and IPv6, and masquerading with nft for
IPv4, from demo script
- get rid of separate slow and fast timers, we don't save any
overhead that way
- stricter checking of buffer lengths as passed to tap handlers
- proper dequeuing from qemu socket back-end: I accidentally trashed
messages that were bundled up together in a single tap read
operation -- the length header tells us what's the size of the next
frame, but there's no apparent limit to the number of messages we
get with one single receive
- rework some bits of the TCP state machine, now passive and active
connection closes appear to be robust -- introduce a new
FIN_WAIT_1_SOCK_FIN state indicating a FIN_WAIT_1 with a FIN flag
from socket
- streamline TCP option parsing routine
- track TCP state changes to stderr (this is temporary, proper
debugging and syslogging support pending)
- observe that multiplying a number by four might very well change
its value, and this happens to be the case for the data offset
from the TCP header as we check if it's the same as the total
length to find out if it's a duplicated ACK segment
- recent estimates suggest that the duration of a millisecond is
closer to a million nanoseconds than a thousand of them, this
trend is now reflected into the timespec_diff_ms() convenience
routine
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This is a reimplementation, partially building on the earlier draft,
that uses L4 sockets (SOCK_DGRAM, SOCK_STREAM) instead of SOCK_RAW,
providing L4-L2 translation functionality without requiring any
security capability.
Conceptually, this follows the design presented at:
https://gitlab.com/abologna/kubevirt-and-kvm/-/blob/master/Networking.md
The most significant novelty here comes from TCP and UDP translation
layers. In particular, the TCP state and translation logic follows
the intent of being minimalistic, without reimplementing a full TCP
stack in either direction, and synchronising as much as possible the
TCP dynamic and flows between guest and host kernel.
Another important introduction concerns addressing, port translation
and forwarding. The Layer 4 implementations now attempt to bind on
all unbound ports, in order to forward connections in a transparent
way.
While at it:
- the qemu 'tap' back-end can't be used as-is by qrap anymore,
because of explicit checks now introduced in qemu to ensure that
the corresponding file descriptor is actually a tap device. For
this reason, qrap now operates on a 'socket' back-end type,
accounting for and building the additional header reporting
frame length
- provide a demo script that sets up namespaces, addresses and
routes, and starts the daemon. A virtual machine started in the
network namespace, wrapped by qrap, will now directly interface
with passt and communicate using Layer 4 sockets provided by the
host kernel.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
