From: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
Date: Wed, 20 Nov 2024 07:43:19 +0000 (+0100)
Subject: selftests/bpf: move ip checksum helper to network helpers
X-Git-Tag: v6.14-rc1~133^2~68^2~5
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f4504af68575c1675235bacd8d36157cfc27ae5e;p=thirdparty%2Fkernel%2Flinux.git

selftests/bpf: move ip checksum helper to network helpers

xdp_metadata test has a small helper computing ipv4 checksums to allow
manually building packets.

Move this helper to network_helpers to share it with other tests.

Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://lore.kernel.org/r/20241120-flow_dissector-v3-9-45b46494f937@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---

diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
index 5764155b6d251..0b2ed90c763fa 100644
--- a/tools/testing/selftests/bpf/network_helpers.h
+++ b/tools/testing/selftests/bpf/network_helpers.h
@@ -105,6 +105,30 @@ static __u16 csum_fold(__u32 csum)
 	return (__u16)~csum;
 }
 
+static __wsum csum_partial(const void *buf, int len, __wsum sum)
+{
+	__u16 *p = (__u16 *)buf;
+	int num_u16 = len >> 1;
+	int i;
+
+	for (i = 0; i < num_u16; i++)
+		sum += p[i];
+
+	return sum;
+}
+
+static inline __sum16 build_ip_csum(struct iphdr *iph)
+{
+	__u32 sum = 0;
+	__u16 *p;
+
+	iph->check = 0;
+	p = (void *)iph;
+	sum = csum_partial(p, iph->ihl << 2, 0);
+
+	return csum_fold(sum);
+}
+
 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 					__u32 len, __u8 proto,
 					__wsum csum)
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
index c87ee2bf558c1..7f8e161655336 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
@@ -133,23 +133,6 @@ static void close_xsk(struct xsk *xsk)
 	munmap(xsk->umem_area, UMEM_SIZE);
 }
 
-static void ip_csum(struct iphdr *iph)
-{
-	__u32 sum = 0;
-	__u16 *p;
-	int i;
-
-	iph->check = 0;
-	p = (void *)iph;
-	for (i = 0; i < sizeof(*iph) / sizeof(*p); i++)
-		sum += p[i];
-
-	while (sum >> 16)
-		sum = (sum & 0xffff) + (sum >> 16);
-
-	iph->check = ~sum;
-}
-
 static int generate_packet(struct xsk *xsk, __u16 dst_port)
 {
 	struct xsk_tx_metadata *meta;
@@ -192,7 +175,7 @@ static int generate_packet(struct xsk *xsk, __u16 dst_port)
 	iph->protocol = IPPROTO_UDP;
 	ASSERT_EQ(inet_pton(FAMILY, TX_ADDR, &iph->saddr), 1, "inet_pton(TX_ADDR)");
 	ASSERT_EQ(inet_pton(FAMILY, RX_ADDR, &iph->daddr), 1, "inet_pton(RX_ADDR)");
-	ip_csum(iph);
+	iph->check = build_ip_csum(iph);
 
 	udph->source = htons(UDP_SOURCE_PORT);
 	udph->dest = htons(dst_port);