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authorMartin KaFai Lau <kafai@fb.com>2020-08-20 12:00:33 -0700
committerAlexei Starovoitov <ast@kernel.org>2020-08-24 14:35:00 -0700
commit7656d68455891f7fc6689f95415fd59e7a1d629b (patch)
tree256a095608155286f836b9019ee268225b404224 /include/linux/tcp.h
parentca584ba070864c606f3a54faaafe774726d5b4a1 (diff)
tcp: Add saw_unknown to struct tcp_options_received
In a later patch, the bpf prog only wants to be called to handle a header option if that particular header option cannot be handled by the kernel. This unknown option could be written by the peer's bpf-prog. It could also be a new standard option that the running kernel does not support it while a bpf-prog can handle it. This patch adds a "saw_unknown" bit to "struct tcp_options_received" and it uses an existing one byte hole to do that. "saw_unknown" will be set in tcp_parse_options() if it sees an option that the kernel cannot handle. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200820190033.2884430-1-kafai@fb.com
Diffstat (limited to 'include/linux/tcp.h')
-rw-r--r--include/linux/tcp.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 2088d5a079af..29d166263ae7 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -92,6 +92,8 @@ struct tcp_options_received {
smc_ok : 1, /* SMC seen on SYN packet */
snd_wscale : 4, /* Window scaling received from sender */
rcv_wscale : 4; /* Window scaling to send to receiver */
+ u8 saw_unknown:1, /* Received unknown option */
+ unused:7;
u8 num_sacks; /* Number of SACK blocks */
u16 user_mss; /* mss requested by user in ioctl */
u16 mss_clamp; /* Maximal mss, negotiated at connection setup */