[PATCH net-next v2] selftests: net: csum: filter packets by source address and port
From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Date: 2026-09-04 03:06:32
Subsystem:
kernel selftest framework, networking [general], the rest · Maintainers:
Shuah Khan, Shuah Khan, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Willem de Bruijn <willemb@google.com>
Add source address and port verification in recv_verify_packet_* and
recv_udp: non-matching packets are skipped.
The receiver reads from PF_PACKET and UDP sockets to verify incoming
packets to test hardware checksum offload. It did not validate the
packet source address or source port.
During tests expecting an invalid checksum (-E), background packets
(with a valid checksum) fail the test.
Also
- add an inter-packet delay to avoid drops from bursts.
- remove a comment that is no longer correct.
Fixes: 91a7de85600d ("selftests/net: add csum offload test")
Signed-off-by: Willem de Bruijn <willemb@google.com>
---
Changes
v1 -> v2
- also check udp socket, with recvfrom
v1: https://lore.kernel.org/netdev/20260831210128.1359978-1-willemdebruijn.kernel@gmail.com/ (local)
---
tools/testing/selftests/net/lib/csum.c | 43 ++++++++++++++++++++++++--
1 file changed, 40 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/net/lib/csum.c b/tools/testing/selftests/net/lib/csum.c
index e28884ce3ab3..5c8f9d175dd3 100644
--- a/tools/testing/selftests/net/lib/csum.c
+++ b/tools/testing/selftests/net/lib/csum.c@@ -2,8 +2,7 @@ /* Test hardware checksum offload: Rx + Tx, IPv4 + IPv6, TCP + UDP. * - * The test runs on two machines to exercise the NIC. For this reason it - * is not integrated in kselftests. + * The test runs on two machines to exercise the NIC. * * CMD=$((./csum -[46] -[tu] -S $SADDR -D $DADDR -[RT] -r 1 $EXTRA_ARGS)) *
@@ -571,15 +570,38 @@ static int recv_prepare_packet(void) static int recv_udp(int fd) { static char buf[MAX_PAYLOAD_LEN]; + struct sockaddr_storage addr; + socklen_t addrlen; int ret, count = 0; while (1) { - ret = recv(fd, buf, sizeof(buf), MSG_DONTWAIT); + addrlen = sizeof(addr); + ret = recvfrom(fd, buf, sizeof(buf), MSG_DONTWAIT, + (struct sockaddr *)&addr, &addrlen); if (ret == -1 && errno == EAGAIN) break; if (ret == -1) error(1, errno, "recv r"); + if (cfg_family == PF_INET) { + struct sockaddr_in *sin = (void *)&addr; + + if (sin->sin_addr.s_addr != cfg_saddr4.sin_addr.s_addr) + continue; + if (!cfg_zero_sum && + sin->sin_port != htons(cfg_port_src)) + continue; + } else { + struct sockaddr_in6 *sin6 = (void *)&addr; + + if (memcmp(&sin6->sin6_addr, &cfg_saddr6.sin6_addr, + sizeof(sin6->sin6_addr))) + continue; + if (!cfg_zero_sum && + sin6->sin6_port != htons(cfg_port_src)) + continue; + } + fprintf(stderr, "rx: udp: len=%u\n", ret); count++; }
@@ -620,6 +642,9 @@ static int recv_verify_packet_tcp(void *th, int len) if (len < sizeof(*tcph) || tcph->dest != htons(cfg_port_dst)) return -1; + if (tcph->source != htons(cfg_port_src)) + return -1; + return recv_verify_csum(th, len, ntohs(tcph->source), tcph->check); }
@@ -647,6 +672,9 @@ static int recv_verify_packet_udp(void *th, int len) return recv_verify_packet_udp_encap(udph + 1, len - sizeof(*udph)); + if (!cfg_zero_sum && udph->source != htons(cfg_port_src)) + return -1; + return recv_verify_csum(th, len, ntohs(udph->source), udph->check); }
@@ -659,6 +687,9 @@ static int recv_verify_packet_ipv4(void *nh, int len) if (len < sizeof(*iph) || iph->protocol != proto) return -1; + if (iph->saddr != cfg_saddr4.sin_addr.s_addr) + return -1; + ip_len = ntohs(iph->tot_len); if (ip_len > len || ip_len < sizeof(*iph)) return -1;
@@ -680,6 +711,9 @@ static int recv_verify_packet_ipv6(void *nh, int len) if (len < sizeof(*ip6h) || ip6h->nexthdr != proto) return -1; + if (memcmp(&ip6h->saddr, &cfg_saddr6.sin6_addr, sizeof(ip6h->saddr))) + return -1; + payload_len = ntohs(ip6h->payload_len); if (payload_len > len - sizeof(*ip6h)) return -1;
@@ -940,6 +974,9 @@ static void do_tx(void) cfg_payload_len = rand() % MAX_PAYLOAD_LEN; buf = build_packet(_buf, sizeof(_buf), &len); } + + /* avoid bursting */ + usleep(20); } if (close(fd))
--
2.55.0.979.g7e5102b832-goog