[PATCH bpf-next v10 1/6] bpf: Fix documentation of th_len in bpf_tcp_{gen,check}_syncookie

Maxim Mikityanskiy
2022-06-15T13:49:13Z

bpf_tcp_gen_syncookie expects the full length of the TCP header (with
all options), and bpf_tcp_check_syncookie accepts lengths bigger than
sizeof(struct tcphdr). Fix the documentation that says these lengths
should be exactly sizeof(struct tcphdr).

While at it, fix a typo in the name of struct ipv6hdr.

Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
---
include/uapi/linux/bpf.h | 10 ++++++----
tools/include/uapi/linux/bpf.h | 10 ++++++----
2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index f4009dbdf62d..f545e39df72a 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3597,10 +3597,11 @@ union bpf_attr {
*
* *iph* points to the start of the IPv4 or IPv6 header, while
* *iph_len* contains **sizeof**\ (**struct iphdr**) or
- * **sizeof**\ (**struct ip6hdr**).
+ * **sizeof**\ (**struct ipv6hdr**).
*
* *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.
@@ -3783,10 +3784,11 @@ union bpf_attr {
*
* *iph* points to the start of the IPv4 or IPv6 header, while
* *iph_len* contains **sizeof**\ (**struct iphdr**) or
- * **sizeof**\ (**struct ip6hdr**).
+ * **sizeof**\ (**struct ipv6hdr**).
*
* *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 with options (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 f4009dbdf62d..f545e39df72a 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3597,10 +3597,11 @@ union bpf_attr {
*
* *iph* points to the start of the IPv4 or IPv6 header, while
* *iph_len* contains **sizeof**\ (**struct iphdr**) or
- * **sizeof**\ (**struct ip6hdr**).
+ * **sizeof**\ (**struct ipv6hdr**).
*
* *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.
@@ -3783,10 +3784,11 @@ union bpf_attr {
*
* *iph* points to the start of the IPv4 or IPv6 header, while
* *iph_len* contains **sizeof**\ (**struct iphdr**) or
- * **sizeof**\ (**struct ip6hdr**).
+ * **sizeof**\ (**struct ipv6hdr**).
*
* *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 with options (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