selftests/bpf: use start_server_str rather than start_reuseport_server in tc_tunnel

test_tc_tunnel currently uses start_reuseport_server because it needs to
frequently start and stop the server, so we need SO_REUSEPORT to avoid
getting errors on server restart due to the socket being in TIME_WAIT
state. But the test is only using one server at a time, so it is a bit
confusing to use this API.

Replace start_reuseport with start_sever_str, and provided the relevant
callback to set SO_REUSEPORT.

Signed-off-by: Alexis Lothoré (eBPF Foundation) <[email protected]>

Author: Tropicao

tools/testing/selftests/bpf/prog_tests/test_tc_tunnel.c

@@ -69,7 +69,7 @@ struct subtest_cfg {
 	int client_egress_prog_fd;
 	int server_ingress_prog_fd;
 	char extra_decap_mod_args[TUNNEL_ARGS_MAX_LEN];
-	int *server_fd;
+	int server_fd;
 };
 
 struct connection {
@@ -131,28 +131,38 @@ static void set_subtest_addresses(struct subtest_cfg *cfg)
 	}
 }
 
+static int reuseport_cb(int fd, void *opts)
+{
+	int one = 1;
+
+	return setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &one, sizeof(one));
+}
+
 static int run_server(struct subtest_cfg *cfg)
 {
 	int family = cfg->ipproto == 6 ? AF_INET6 : AF_INET;
+	struct network_helper_opts opts = {
+		.timeout_ms = TIMEOUT_MS,
+		.post_socket_cb	= reuseport_cb,
+	};
 	struct nstoken *nstoken;
 
 	nstoken = open_netns(SERVER_NS);
 	if (!ASSERT_OK_PTR(nstoken, "open server ns"))
 		return -1;
 
-	cfg->server_fd = start_reuseport_server(family, SOCK_STREAM,
-						cfg->server_addr, TEST_PORT,
-						TIMEOUT_MS, 1);
+	cfg->server_fd = start_server_str(family, SOCK_STREAM, cfg->server_addr,
+					  TEST_PORT, &opts);
 	close_netns(nstoken);
-	if (!ASSERT_OK_PTR(cfg->server_fd, "start server"))
+	if (!ASSERT_OK_FD(cfg->server_fd, "start server"))
 		return -1;
 
 	return 0;
 }
 
 static void stop_server(struct subtest_cfg *cfg)
 {
-	free_fds(cfg->server_fd, 1);
+	close(cfg->server_fd);
 }
 
 static int check_server_rx_data(struct subtest_cfg *cfg,
@@ -188,7 +198,7 @@ static struct connection *connect_client_to_server(struct subtest_cfg *cfg)
 		return NULL;
 	}
 
-	server_fd = accept(*cfg->server_fd, NULL, NULL);
+	server_fd = accept(cfg->server_fd, NULL, NULL);
 	if (server_fd < 0) {
 		close(client_fd);
 		free(conn);