Commit f6642de0 authored by Stanislav Fomichev's avatar Stanislav Fomichev Committed by Alexei Starovoitov
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selftests/bpf: Add csum helpers 



Checksum helpers will be used to calculate pseudo-header checksum in
AF_XDP metadata selftests.

The helpers are mirroring existing kernel ones:
- csum_tcpudp_magic : IPv4 pseudo header csum
- csum_ipv6_magic : IPv6 pseudo header csum
- csum_fold : fold csum and do one's complement

Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20231127190319.1190813-11-sdf@google.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent df3ed000

tools/testing/selftests/bpf/network_helpers.h

+43 −0
Original line number Diff line number Diff line
@@ -71,4 +71,47 @@ struct nstoken; 
 */

struct nstoken *open_netns(const char *name);

void close_netns(struct nstoken *token);



static __u16 csum_fold(__u32 csum)

{

	csum = (csum & 0xffff) + (csum >> 16);

	csum = (csum & 0xffff) + (csum >> 16);



	return (__u16)~csum;

}



static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,

					__u32 len, __u8 proto,

					__wsum csum)

{

	__u64 s = csum;



	s += (__u32)saddr;

	s += (__u32)daddr;

	s += htons(proto + len);

	s = (s & 0xffffffff) + (s >> 32);

	s = (s & 0xffffffff) + (s >> 32);



	return csum_fold((__u32)s);

}



static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,

				      const struct in6_addr *daddr,

					__u32 len, __u8 proto,

					__wsum csum)

{

	__u64 s = csum;

	int i;



	for (i = 0; i < 4; i++)

		s += (__u32)saddr->s6_addr32[i];

	for (i = 0; i < 4; i++)

		s += (__u32)daddr->s6_addr32[i];

	s += htons(proto + len);

	s = (s & 0xffffffff) + (s >> 32);

	s = (s & 0xffffffff) + (s >> 32);



	return csum_fold((__u32)s);

}



#endif