Commit 752fddc0 authored by Alexis Lothoré (eBPF Foundation)'s avatar Alexis Lothoré (eBPF Foundation) Committed by Alexei Starovoitov
Browse files

selftests/bpf: document pseudo-header checksum helpers 



network_helpers.h provides helpers to compute checksum for pseudo
headers but no helpers to compute the global checksums.

Before adding those, clarify csum_tcpudp_magic and csum_ipv6_magic
purpose by adding some documentation.

Signed-off-by: default avatarAlexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
Acked-by: default avatarStanislav Fomichev <sdf@fomichev.me>
Link: https://lore.kernel.org/r/20241120-flow_dissector-v3-10-45b46494f937@bootlin.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent f4504af6

tools/testing/selftests/bpf/network_helpers.h

+30 −0
Original line number Diff line number Diff line
@@ -129,6 +129,21 @@ static inline __sum16 build_ip_csum(struct iphdr *iph) 
	return csum_fold(sum);

}



/**

 * csum_tcpudp_magic - compute IP pseudo-header checksum

 *

 * Compute the IPv4 pseudo header checksum. The helper can take a

 * accumulated sum from the transport layer to accumulate it and directly

 * return the transport layer

 *

 * @saddr: IP source address

 * @daddr: IP dest address

 * @len: IP data size

 * @proto: transport layer protocol

 * @csum: The accumulated partial sum to add to the computation

 *

 * Returns the folded sum

 */

static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,

					__u32 len, __u8 proto,

					__wsum csum)
@@ -144,6 +159,21 @@ static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, 
	return csum_fold((__u32)s);

}



/**

 * csum_ipv6_magic - compute IPv6 pseudo-header checksum

 *

 * Compute the ipv6 pseudo header checksum. The helper can take a

 * accumulated sum from the transport layer to accumulate it and directly

 * return the transport layer

 *

 * @saddr: IPv6 source address

 * @daddr: IPv6 dest address

 * @len: IPv6 data size

 * @proto: transport layer protocol

 * @csum: The accumulated partial sum to add to the computation

 *

 * Returns the folded sum

 */

static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,

				      const struct in6_addr *daddr,

					__u32 len, __u8 proto,