selftests/bpf: Add test to verify the fix for bpf_setsockopt() helper

Verify the fix by:

1. Attach cgroup sockops prog.
2. Build a tcp connection using ipv4 addr in ipv6 socket.
3. Verify the return value of bpf_setsockopt() helper.

Assisted-by: Codex:gpt-5.5-xhigh
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260613162443.60515-3-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/testing/selftests/bpf/prog_tests/setget_sockopt.c b/tools/testing/selftests/bpf/prog_tests/setget_sockopt.c
index 77fe1bfb7504e0d9c48e4ded153478c4ceeeb406..4e91d9b615cee5843a00f45d0e005490ee234e40 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/setget_sockopt.c
+++ b/tools/testing/selftests/bpf/prog_tests/setget_sockopt.c
@@ -199,6 +199,83 @@ err_out:
        bpf_link__destroy(getsockopt_link);
 }
 
+static int connect_to_v4mapped_v6_fd(int server_fd)
+{
+       struct sockaddr_storage addr;
+       struct sockaddr_in *addr4 = (void *)&addr;
+       socklen_t addrlen = sizeof(addr);
+       struct sockaddr_in6 addr6 = {};
+       int fd = -1, v6only = 0, err;
+
+       err = getsockname(server_fd, (struct sockaddr *)&addr, &addrlen);
+       if (!ASSERT_OK(err, "getsockname"))
+               return -1;
+
+       fd = socket(AF_INET6, SOCK_STREAM, 0);
+       if (!ASSERT_GE(fd, 0, "socket"))
+               return -1;
+
+       err = settimeo(fd, 0);
+       if (!ASSERT_OK(err, "settimeo"))
+               goto err_out;
+
+       err = setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &v6only, sizeof(v6only));
+       if (!ASSERT_OK(err, "clear_v6only"))
+               goto err_out;
+
+       addr6.sin6_family = AF_INET6;
+       addr6.sin6_port = addr4->sin_port;
+       addr6.sin6_addr.s6_addr[10] = 0xff;
+       addr6.sin6_addr.s6_addr[11] = 0xff;
+       memcpy(&addr6.sin6_addr.s6_addr[12], &addr4->sin_addr, sizeof(addr4->sin_addr));
+
+       err = connect(fd, (struct sockaddr *)&addr6, sizeof(addr6));
+       if (!ASSERT_OK(err, "connect"))
+               goto err_out;
+
+       return fd;
+
+err_out:
+       close(fd);
+       return -1;
+}
+
+static void test_v4mapped_v6_ip_tos(void)
+{
+       struct setget_sockopt__bss *bss = skel->bss;
+       int sfd = -1, fd = -1, got = 0, exp = 0x1c;
+       socklen_t optlen;
+
+       memset(bss, 0, sizeof(*bss));
+       bss->v4mapped_v6_ip_tos_enable = 1;
+       bss->v4mapped_v6_ip_tos_ret = -1;
+       bss->v4mapped_v6_ip_tos_val = exp;
+
+       sfd = start_server(AF_INET, SOCK_STREAM, addr4_str, 0, 0);
+       if (!ASSERT_GE(sfd, 0, "start_server"))
+               goto err_out;
+
+       fd = connect_to_v4mapped_v6_fd(sfd);
+       if (!ASSERT_GE(fd, 0, "connect_to_v4mapped_v6_fd"))
+               goto err_out;
+
+       ASSERT_GT(bss->v4mapped_v6_ip_tos_cnt, 0, "v4mapped_v6_ip_tos_cnt");
+       ASSERT_EQ(bss->v4mapped_v6_ip_tos_ret, 0, "v4mapped_v6_ip_tos_ret");
+
+       optlen = sizeof(got);
+       if (!ASSERT_OK(getsockopt(fd, SOL_IP, IP_TOS, &got, &optlen), "getsockopt_ip_tos"))
+               goto err_out;
+
+       ASSERT_EQ(got, exp, "ip_tos");
+
+err_out:
+       bss->v4mapped_v6_ip_tos_enable = 0;
+       if (fd >= 0)
+               close(fd);
+       if (sfd >= 0)
+               close(sfd);
+}
+
 void test_setget_sockopt(void)
 {
        cg_fd = test__join_cgroup(CG_NAME);
@@ -238,6 +315,7 @@ void test_setget_sockopt(void)
        test_ktls(AF_INET);
        test_nonstandard_opt(AF_INET);
        test_nonstandard_opt(AF_INET6);
+       test_v4mapped_v6_ip_tos();
 
 done:
        setget_sockopt__destroy(skel);

diff --git a/tools/testing/selftests/bpf/progs/setget_sockopt.c b/tools/testing/selftests/bpf/progs/setget_sockopt.c
index d330b15119794d31ab335c7078b8b0f08a8a9857..636a7cd8e2fa4ef537ee334a9303547de227505e 100644 (file)
--- a/tools/testing/selftests/bpf/progs/setget_sockopt.c
+++ b/tools/testing/selftests/bpf/progs/setget_sockopt.c
@@ -387,6 +387,24 @@ int _getsockopt(struct bpf_sockopt *ctx)
        return 1;
 }
 
+int v4mapped_v6_ip_tos_enable;
+int v4mapped_v6_ip_tos_ret;
+int v4mapped_v6_ip_tos_cnt;
+int v4mapped_v6_ip_tos_val;
+
+static void test_v4mapped_v6_ip_tos(struct bpf_sock_ops *skops)
+{
+       int tos = v4mapped_v6_ip_tos_val;
+
+       if (!v4mapped_v6_ip_tos_enable || skops->op != BPF_SOCK_OPS_TCP_CONNECT_CB)
+               return;
+       if (skops->family != AF_INET6)
+               return;
+
+       v4mapped_v6_ip_tos_cnt++;
+       v4mapped_v6_ip_tos_ret = bpf_setsockopt(skops, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
+}
+
 SEC("sockops")
 int skops_sockopt(struct bpf_sock_ops *skops)
 {
@@ -401,6 +419,11 @@ int skops_sockopt(struct bpf_sock_ops *skops)
        if (!sk)
                return 1;
 
+       if (v4mapped_v6_ip_tos_enable) {
+               test_v4mapped_v6_ip_tos(skops);
+               return 1;
+       }
+
        switch (skops->op) {
        case BPF_SOCK_OPS_TCP_LISTEN_CB:
                nr_listen += !(bpf_test_sockopt(skops, sk) ||