linux/include/trace
Alice Mikityanska 5329647dad net: Use helpers to get/set UDP len tree-wide
Since BIG TCP for UDP tunnels will start using len=0 in the UDP header
as an indicator of a GSO packet bigger than 65535 bytes, this commit
introduces the following getter and setters to use tree-wide, in order
to explicitly mark places where len=0 may be expected, and handle them
properly:

1. udp_set_len() sets uh->len to its real value if it's not bigger than
65535, and to 0 otherwise: to be used in GSO context with aggregated
packets.

2. udp_set_len_short() is to be used when the length is known to fit 16
bits. It WARNs when the caller tries to assign a bigger value if
CONFIG_DEBUG_NET=y.

3. udp_get_len_short() returns len in host byte order: to be used on the
RX side to deal with non-aggregated packets, or to access the raw value
of the len field.

4. udp_get_len() decodes uh->len set by udp_set_len(). It checks whether
the packet is GSO to guard from malformed packets.

At the moment udp_set_len() is not used, a following commit will start
using it after enabling len>65535 for GSO.

Raw uh->len (in network byte order) is still accessed in a few places
for checksum calculation purposes, and to decode len=0 in udpv6_rcv for
jumbograms. udp_rcv and udpv6_rcv will be addressed by the commit that
starts using udp_set_len() to set UDP len=0 for BIG TCP packets in UDP
tunnels.

Signed-off-by: Alice Mikityanska <alice@isovalent.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Acked-by: Jason A. Donenfeld <Jason@zx2c4.com>
Link: https://patch.msgid.link/20260710134242.216538-2-alice.kernel@fastmail.im
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-07-22 13:47:02 +02:00
..
events net: Use helpers to get/set UDP len tree-wide 2026-07-22 13:47:02 +02:00
misc fsnotify: new tracepoint in fsnotify() 2026-05-15 19:24:33 +02:00
stages mm.git review status for linus..mm-stable 2026-04-15 12:59:16 -07:00
bpf_probe.h bpf: Add sleepable support for raw tracepoint programs 2026-04-22 22:44:24 +02:00
define_custom_trace.h tracing: Add TRACE_CUSTOM_EVENT() macro 2022-03-11 11:49:24 -05:00
define_remote_events.h tracing: Add helpers to create trace remote events 2026-03-09 12:33:54 -04:00
define_trace.h tracepoint: Have tracepoints created with DECLARE_TRACE() have _tp suffix 2025-05-14 11:19:32 -04:00
perf.h tracing: perf: Have perf tracepoint callbacks always disable preemption 2026-01-30 10:43:35 -05:00
syscall.h tracing: Display some syscall arrays as strings 2025-10-28 20:10:58 -04:00
trace_custom_events.h tracing: Rename the staging files for trace_events 2022-04-02 08:40:04 -04:00
trace_events.h tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast 2026-01-30 10:44:11 -05:00