passt/checksum.h, branch bug205

Add missing includes to headers

2026-03-04T16:39:57+00:00

Support build systems like bazel that check that headers are
self-contained.

Also update includes so that clang-include-cleaner succeeds.

Tested with:
clang-include-cleaner-19 --extra-arg=-D_GNU_SOURCE --extra-arg=-DPAGE_SIZE=4096 --extra-arg=-DVERSION=\"git\" --extra-arg=-DHAS_GETRANDOM *.h *.c

Signed-off-by: Peter Foley 
Signed-off-by: Stefano Brivio

checksum: Don't export various functions

2025-03-07T01:21:24+00:00

Several of the exposed functions in checksum.h are no longer directly used.
Remove them from the header, and make static.  In particular sum_16b()
should not be used outside: generally csum_unfolded() should be used which
will automatically use either the AVX2 optimized version or sum_16b() as
necessary.

csum_fold() and csum() could have external uses, but they're not used right
now.  We can expose them again if we need to.

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

iov, checksum: Replace csum_iov() with csum_iov_tail()

2024-11-28T13:03:16+00:00

We usually want to checksum only the tail part of a frame, excluding at
least some headers.  csum_iov() does that for a frame represented as an
IO vector, not actually summing the entire IO vector.  We now have struct
iov_tail to explicitly represent this construct, so replace csum_iov()
with csum_iov_tail() taking that representation rather than 3 parameters.

We propagate the same change to csum_udp4() and csum_udp6() which take
similar parameters.  This slightly simplifies the code, and will allow some
further simplifications as struct iov_tail is more widely used.

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

udp: Update UDP checksum using an iovec array

2024-10-04T12:51:13+00:00

As for tcp_update_check_tcp4()/tcp_update_check_tcp6(),
change csum_udp4() and csum_udp6() to use an iovec array.

Signed-off-by: Laurent Vivier 
Signed-off-by: Stefano Brivio

checksum: Add an offset argument in csum_iov()

2024-10-04T12:51:08+00:00

The offset allows any headers that are not part of the data
to checksum to be skipped.

Signed-off-by: Laurent Vivier 
Signed-off-by: Stefano Brivio

treewide: Standardise variable names for various packet lengths

2024-05-02T14:13:23+00:00

At various points we need to track the lengths of a packet including or
excluding various different sets of headers.  We don't always use the same
variable names for doing so.  Worse in some places we use the same name
for different things: e.g. tcp_fill_headers[46]() use ip_len for the
length including the IP headers, but then tcp_send_flag() which calls it
uses it to mean the IP payload length only.

To improve clarity, standardise on these names:
   dlen:		L4 protocol payload length ("data length")
   l4len:		plen + length of L4 protocol header
   l3len:		l4len + length of IPv4/IPv6 header
   l2len:		l3len + length of L2 (ethernet) header

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

checksum: introduce functions to compute the header part checksum for TCP/UDP

2024-03-06T07:03:47+00:00

The TCP and UDP checksums are computed using the data in the TCP/UDP
payload but also some informations in the IP header (protocol,
length, source and destination addresses).

We add two functions, proto_ipv4_header_psum() and
proto_ipv6_header_psum(), to compute the checksum of the IP
header part.

Signed-off-by: Laurent Vivier 
Message-ID: <20240303135114.1023026-8-lvivier@redhat.com>
Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio

checksum: use csum_ip4_header() in udp.c and tcp.c

2024-03-06T07:03:44+00:00

We can find the same function to compute the IPv4 header
checksum in tcp.c, udp.c and tap.c

Use the function defined for tap.c, csum_ip4_header(), but
with the code used in tcp.c and udp.c as it doesn't need a fully
initialiazed IPv4 header, only protocol, tot_len, saddr and daddr.

Signed-off-by: Laurent Vivier 
Reviewed-by: David Gibson 
Message-ID: <20240303135114.1023026-7-lvivier@redhat.com>
[dwg: Fix weird cppcheck regression; it appears to be a problem
 in pre-existing code, but somehow this patch is exposing it]
Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio

checksum: add csum_iov()

2024-03-06T07:03:36+00:00

Introduce the function csum_unfolded() that computes the unfolded
32-bit checksum of a data buffer, and call it from csum() that returns
the folded value.

Introduce csum_iov() that computes the checksum using csum_folded() on
all vectors of the iovec array and returns the folded result.

Signed-off-by: Laurent Vivier 
Reviewed-by: David Gibson 
Message-ID: <20240303135114.1023026-4-lvivier@redhat.com>
[dwg: Fixed trivial cppcheck & clang-tidy regressions]
Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio

passt: Relicense to GPL 2.0, or any later version

2023-04-06T16:00:33+00:00

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