From f6642de0c3e94d3ef6f44e127d11fcf4138873f7 Mon Sep 17 00:00:00 2001
From: Stanislav Fomichev <sdf@google.com>
Date: Mon, 27 Nov 2023 11:03:16 -0800
Subject: [PATCH] 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: 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>
---
tools/testing/selftests/bpf/network_helpers.h | 43 +++++++++++++++++++
1 file changed, 43 insertions(+)
diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
index 34f1200a781b5..94b9be24e39bc 100644
--- a/tools/testing/selftests/bpf/network_helpers.h
+++ b/tools/testing/selftests/bpf/network_helpers.h
@@ -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
--
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