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| author | Martin KaFai Lau <kafai@fb.com> | 2020-08-20 12:00:33 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-08-24 14:35:00 -0700 |
| commit | 7656d68455891f7fc6689f95415fd59e7a1d629b (patch) | |
| tree | 256a095608155286f836b9019ee268225b404224 /include/linux/tcp.h | |
| parent | ca584ba070864c606f3a54faaafe774726d5b4a1 (diff) | |
| download | lwn-7656d68455891f7fc6689f95415fd59e7a1d629b.tar.gz lwn-7656d68455891f7fc6689f95415fd59e7a1d629b.zip | |
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.h | 2 |
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 */ |