[PATCH bpf v2 4/4] bpf: Fix documentation of th_len in bpf_tcp_{gen,check}_syncookie
From: Maxim Mikityanskiy <hidden>
Date: 2022-01-24 15:13:18
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
bpf_tcp_gen_syncookie and bpf_tcp_check_syncookie expect the full length
of the TCP header (with all extensions). Fix the documentation that says
it should be sizeof(struct tcphdr).
Fixes: 399040847084 ("bpf: add helper to check for a valid SYN cookie")
Fixes: 70d66244317e ("bpf: add bpf_tcp_gen_syncookie helper")
Signed-off-by: Maxim Mikityanskiy <redacted>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
---
include/uapi/linux/bpf.h | 6 ++++--
tools/include/uapi/linux/bpf.h | 6 ++++--
2 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index b0383d371b9a..520f1e557dce 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h@@ -3553,7 +3553,8 @@ union bpf_attr { * **sizeof**\ (**struct ip6hdr**). * * *th* points to the start of the TCP header, while *th_len* - * contains **sizeof**\ (**struct tcphdr**). + * contains the length of the TCP header (at least + * **sizeof**\ (**struct tcphdr**)). * Return * 0 if *iph* and *th* are a valid SYN cookie ACK, or a negative * error otherwise.
@@ -3739,7 +3740,8 @@ union bpf_attr { * **sizeof**\ (**struct ip6hdr**). * * *th* points to the start of the TCP header, while *th_len* - * contains the length of the TCP header. + * contains the length of the TCP header (at least + * **sizeof**\ (**struct tcphdr**)). * Return * On success, lower 32 bits hold the generated SYN cookie in * followed by 16 bits which hold the MSS value for that cookie,
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index b0383d371b9a..520f1e557dce 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h@@ -3553,7 +3553,8 @@ union bpf_attr { * **sizeof**\ (**struct ip6hdr**). * * *th* points to the start of the TCP header, while *th_len* - * contains **sizeof**\ (**struct tcphdr**). + * contains the length of the TCP header (at least + * **sizeof**\ (**struct tcphdr**)). * Return * 0 if *iph* and *th* are a valid SYN cookie ACK, or a negative * error otherwise.
@@ -3739,7 +3740,8 @@ union bpf_attr { * **sizeof**\ (**struct ip6hdr**). * * *th* points to the start of the TCP header, while *th_len* - * contains the length of the TCP header. + * contains the length of the TCP header (at least + * **sizeof**\ (**struct tcphdr**)). * Return * On success, lower 32 bits hold the generated SYN cookie in * followed by 16 bits which hold the MSS value for that cookie,
--
2.30.2