[PATCH bpf-next v11 5/5] selftests/bpf: add bpf_icmp_send no route test
From: Mahe Tardy <hidden>
Date: 2026-07-09 14:49:17
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Linus Torvalds
For normal live cgroup_skb paths, the skb should already be routed. The exception is for test run via BPF_PROG_TEST_RUN with packets created via bpf_prog_test_run_skb. Those lack dst route and thus the icmp_send would quietly fail by returning early. This test exercises this and makes sure the kfunc returns -ENETUNREACH. Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com> Reviewed-by: Jordan Rife <redacted> Signed-off-by: Mahe Tardy <redacted> --- .../bpf/prog_tests/icmp_send_kfunc.c | 49 +++++++++++++++++++ 1 file changed, 49 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/icmp_send_kfunc.c b/tools/testing/selftests/bpf/prog_tests/icmp_send_kfunc.c
index bb532aa0d158..9318d4bc7ce8 100644
--- a/tools/testing/selftests/bpf/prog_tests/icmp_send_kfunc.c
+++ b/tools/testing/selftests/bpf/prog_tests/icmp_send_kfunc.c@@ -169,6 +169,49 @@ static void run_icmp_test(struct icmp_send *skel, int af, const char *ip, } } +static void run_icmp_no_route_test(struct icmp_send *skel, int af) +{ + union { + struct ipv4_packet v4; + struct ipv6_packet v6; + } pkt; + DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts, + .data_in = &pkt, + ); + int err; + + switch (af) { + case AF_INET: + pkt.v4 = pkt_v4; + pkt.v4.iph.version = 4; + pkt.v4.iph.daddr = htonl(INADDR_LOOPBACK); + pkt.v4.tcp.dest = htons(80); + opts.data_size_in = sizeof(pkt.v4); + skel->bss->unreach_type = ICMP_DEST_UNREACH; + break; + case AF_INET6: + pkt.v6 = pkt_v6; + pkt.v6.iph.version = 6; + pkt.v6.iph.daddr = in6addr_loopback; + pkt.v6.tcp.dest = htons(80); + opts.data_size_in = sizeof(pkt.v6); + skel->bss->unreach_type = ICMPV6_DEST_UNREACH; + break; + default: + ASSERT_FAIL("af_not_supported"); + return; + } + + skel->bss->server_port = 80; + skel->data->kfunc_ret = KFUNC_RET_UNSET; + + err = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.egress), &opts); + if (!ASSERT_OK(err, "test_run")) + return; + + ASSERT_EQ(skel->data->kfunc_ret, -ENETUNREACH, "kfunc_ret_no_route"); +} + void test_icmp_send_unreach_cgroup(void) { struct icmp_send *skel;
@@ -193,6 +236,12 @@ void test_icmp_send_unreach_cgroup(void) if (test__start_subtest("ipv6")) run_icmp_test(skel, AF_INET6, "::1", ICMPV6_REJECT_ROUTE); + if (test__start_subtest("no_route_ipv4")) + run_icmp_no_route_test(skel, AF_INET); + + if (test__start_subtest("no_route_ipv6")) + run_icmp_no_route_test(skel, AF_INET6); + cleanup: icmp_send__destroy(skel); if (cgroup_fd >= 0) --
2.34.1