Commit graph

5 commits

Author SHA1 Message Date
Stefano Brivio
087b5f4dbb LICENSES: Add license text files, add missing notices, fix SPDX tags
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>
2021-10-20 08:29:30 +02:00
Stefano Brivio
64a0ba3b27 udp: Introduce recvmmsg()/sendmmsg(), zero-copy path from socket
Packets are received directly onto pre-cooked, static buffers
for IPv4 (with partial checksum pre-calculation) and IPv6 frames,
with pre-filled Ethernet addresses and, partially, IP headers,
and sent out from the same buffers with sendmmsg(), for both
passt and pasta (non-local traffic only) modes.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2021-07-21 12:01:04 +02:00
Stefano Brivio
33482d5bf2 passt: Add PASTA mode, major rework
PASTA (Pack A Subtle Tap Abstraction) provides quasi-native host
connectivity to an otherwise disconnected, unprivileged network
and user namespace, similarly to slirp4netns. Given that the
implementation is largely overlapping with PASST, no separate binary
is built: 'pasta' (and 'passt4netns' for clarity) both link to
'passt', and the mode of operation is selected depending on how the
binary is invoked. Usage example:

	$ unshare -rUn
	# echo $$
	1871759

	$ ./pasta 1871759	# From another terminal

	# udhcpc -i pasta0 2>/dev/null
	# ping -c1 pasta.pizza
	PING pasta.pizza (64.190.62.111) 56(84) bytes of data.
	64 bytes from 64.190.62.111 (64.190.62.111): icmp_seq=1 ttl=255 time=34.6 ms

	--- pasta.pizza ping statistics ---
	1 packets transmitted, 1 received, 0% packet loss, time 0ms
	rtt min/avg/max/mdev = 34.575/34.575/34.575/0.000 ms
	# ping -c1 spaghetti.pizza
	PING spaghetti.pizza(2606:4700:3034::6815:147a (2606:4700:3034::6815:147a)) 56 data bytes
	64 bytes from 2606:4700:3034::6815:147a (2606:4700:3034::6815:147a): icmp_seq=1 ttl=255 time=29.0 ms

	--- spaghetti.pizza ping statistics ---
	1 packets transmitted, 1 received, 0% packet loss, time 0ms
	rtt min/avg/max/mdev = 28.967/28.967/28.967/0.000 ms

This entails a major rework, especially with regard to the storage of
tracked connections and to the semantics of epoll(7) references.

Indexing TCP and UDP bindings merely by socket proved to be
inflexible and unsuitable to handle different connection flows: pasta
also provides Layer-2 to Layer-2 socket mapping between init and a
separate namespace for local connections, using a pair of splice()
system calls for TCP, and a recvmmsg()/sendmmsg() pair for UDP local
bindings. For instance, building on the previous example:

	# ip link set dev lo up
	# iperf3 -s

	$ iperf3 -c ::1 -Z -w 32M -l 1024k -P2 | tail -n4
	[SUM]   0.00-10.00  sec  52.3 GBytes  44.9 Gbits/sec  283             sender
	[SUM]   0.00-10.43  sec  52.3 GBytes  43.1 Gbits/sec                  receiver

	iperf Done.

epoll(7) references now include a generic part in order to
demultiplex data to the relevant protocol handler, using 24
bits for the socket number, and an opaque portion reserved for
usage by the single protocol handlers, in order to track sockets
back to corresponding connections and bindings.

A number of fixes pertaining to TCP state machine and congestion
window handling are also included here.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2021-07-17 11:04:22 +02:00
Stefano Brivio
19d254bbbb passt: Add support for multiple instances in different network namespaces
...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>
2021-05-21 11:14:51 +02:00
Stefano Brivio
17337a736f passt: Introduce packet capture implementation
With -DDEBUG, passt now saves guest-side traffic captures in
pcap format at /tmp/passt_<ISO8601 timestamp>.pcap. The timestamp
refers to time and date of start-up.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2021-05-21 11:14:48 +02:00