linux/tools/include
Daniel Borkmann 7cdec54f97 bpf: Add csum_level helper for fixing up csum levels
Add a bpf_csum_level() helper which BPF programs can use in combination
with bpf_skb_adjust_room() when they pass in BPF_F_ADJ_ROOM_NO_CSUM_RESET
flag to the latter to avoid falling back to CHECKSUM_NONE.

The bpf_csum_level() allows to adjust CHECKSUM_UNNECESSARY skb->csum_levels
via BPF_CSUM_LEVEL_{INC,DEC} which calls __skb_{incr,decr}_checksum_unnecessary()
on the skb. The helper also allows a BPF_CSUM_LEVEL_RESET which sets the skb's
csum to CHECKSUM_NONE as well as a BPF_CSUM_LEVEL_QUERY to just return the
current level. Without this helper, there is no way to otherwise adjust the
skb->csum_level. I did not add an extra dummy flags as there is plenty of free
bitspace in level argument itself iff ever needed in future.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Lorenz Bauer <lmb@cloudflare.com>
Link: https://lore.kernel.org/bpf/279ae3717cb3d03c0ffeb511493c93c450a01e1a.1591108731.git.daniel@iogearbox.net
2020-06-02 11:50:23 -07:00
..
asm tools: Add missing stdio.h include to asm/bug.h header 2019-09-25 09:51:44 -03:00
asm-generic treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
linux tools headers: Synchronize linux/bits.h with the kernel sources 2020-04-14 11:40:05 -03:00
nolibc tool headers nolibc: add RISCV support 2019-05-08 15:48:43 +02:00
tools tools: bpf: fix license for a compat header file 2018-09-19 23:49:58 +02:00
trace/events tools/lib/lockdep: Remove private kernel headers 2017-06-05 09:28:14 +02:00
uapi bpf: Add csum_level helper for fixing up csum levels 2020-06-02 11:50:23 -07:00
vdso tools headers: Synchronize linux/bits.h with the kernel sources 2020-04-14 11:40:05 -03:00