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

Before adding those, rename the pseudo header checksum helper to clarify
their role.

Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
Changes in v2:
- new patch
---
 tools/testing/selftests/bpf/network_helpers.h         | 14 +++++++-------
 tools/testing/selftests/bpf/prog_tests/xdp_metadata.c |  5 +++--
 tools/testing/selftests/bpf/xdp_hw_metadata.c         | 12 ++++++++----
 3 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
index c9b72960c651ab9fb249f6eb9e153b8416b7a488..6d1ae56080c56a65c437899c32566f0e4c496c33 100644
--- a/tools/testing/selftests/bpf/network_helpers.h
+++ b/tools/testing/selftests/bpf/network_helpers.h
@@ -127,9 +127,9 @@ static inline __sum16 build_ip_csum(struct iphdr *iph)
 	return csum_fold(sum);
 }
 
-static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
-					__u32 len, __u8 proto,
-					__wsum csum)
+static inline __sum16 build_ipv4_pseudo_header_csum(__be32 saddr, __be32 daddr,
+						    __u32 len, __u8 proto,
+						    __wsum csum)
 {
 	__u64 s = csum;
 
@@ -142,10 +142,10 @@ static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 	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)
+static inline __sum16
+build_ipv6_pseudo_header_csum(const struct in6_addr *saddr,
+			      const struct in6_addr *daddr, __u32 len,
+			      __u8 proto, __wsum csum)
 {
 	__u64 s = csum;
 	int i;
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
index 7f8e161655336127e5bd7a573d1a09db85a92f53..0e69390ac0c2d8959c614e7d29fea1c31910cf9b 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
@@ -180,8 +180,9 @@ static int generate_packet(struct xsk *xsk, __u16 dst_port)
 	udph->source = htons(UDP_SOURCE_PORT);
 	udph->dest = htons(dst_port);
 	udph->len = htons(sizeof(*udph) + UDP_PAYLOAD_BYTES);
-	udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
-					 ntohs(udph->len), IPPROTO_UDP, 0);
+	udph->check = ~build_ipv4_pseudo_header_csum(iph->saddr, iph->daddr,
+						     ntohs(udph->len),
+						     IPPROTO_UDP, 0);
 
 	memset(udph + 1, 0xAA, UDP_PAYLOAD_BYTES);
 
diff --git a/tools/testing/selftests/bpf/xdp_hw_metadata.c b/tools/testing/selftests/bpf/xdp_hw_metadata.c
index 6f9956eed797f30b9611596909ef2954654eab18..0ef3c020cc9f77a0a149859493468313071ad66b 100644
--- a/tools/testing/selftests/bpf/xdp_hw_metadata.c
+++ b/tools/testing/selftests/bpf/xdp_hw_metadata.c
@@ -378,11 +378,15 @@ static void ping_pong(struct xsk *xsk, void *rx_packet, clockid_t clock_id)
 
 	want_csum = udph->check;
 	if (ip6h)
-		udph->check = ~csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
-					       ntohs(udph->len), IPPROTO_UDP, 0);
+		udph->check = ~build_ipv6_pseudo_header_csum(&ip6h->saddr,
+							     &ip6h->daddr,
+							     ntohs(udph->len),
+							     IPPROTO_UDP, 0);
 	else
-		udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
-						 ntohs(udph->len), IPPROTO_UDP, 0);
+		udph->check = ~build_ipv4_pseudo_header_csum(iph->saddr,
+							     iph->daddr,
+							     ntohs(udph->len),
+							     IPPROTO_UDP, 0);
 
 	meta->flags |= XDP_TXMD_FLAGS_CHECKSUM;
 	if (iph)

-- 
2.47.0

On 11/14, Alexis Lothoré (eBPF Foundation) wrote:
> network_helpers.h provides helpers to compute checksum for pseudo
> headers but no helpers to compute the global checksums.
> 
> Before adding those, rename the pseudo header checksum helper to clarify
> their role.

Same here: let's keep the old names? They are matching the ones we
have on the kernel side so it's easy to find them. I do agree that
the naming is unfortunate :-( If you prefer, maybe clarify with
a doc?

On 11/15/24 16:33, Stanislav Fomichev wrote:
> On 11/14, Alexis Lothoré (eBPF Foundation) wrote:
>> network_helpers.h provides helpers to compute checksum for pseudo
>> headers but no helpers to compute the global checksums.
>>
>> Before adding those, rename the pseudo header checksum helper to clarify
>> their role.
> 
> Same here: let's keep the old names? They are matching the ones we
> have on the kernel side so it's easy to find them. I do agree that
> the naming is unfortunate :-( If you prefer, maybe clarify with
> a doc?

Yeah, I did not really get the meaning of "magic" here, but ok, let's keep the
original name to keep it synced with the kernel functions. I'll replace the
rename with some doc.


-- 
Alexis Lothoré, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com