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selftests/bpf: Add csum helpers

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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: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20231127190319.1190813-11-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Stanislav Fomichev 2023-11-27 11:03:16 -08:00 committed by Alexei Starovoitov
parent df3ed0003e
commit f6642de0c3
1 changed files with 43 additions and 0 deletions
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43
tools/testing/selftests/bpf/network_helpers.h
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@ -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