selftests/net: Add TCP-AO selfconnect/simultaneous connect test

Check that a rare functionality of TCP named self-connect works with
TCP-AO. This "under the cover" also checks TCP simultaneous connect
(TCP_SYN_RECV socket state), which would be harder to check other ways.

In order to verify that it's indeed TCP simultaneous connect, check
the counters TCPChallengeACK and TCPSYNChallenge.

Sample of the output:
> # ./self-connect_ipv6
> 1..4
> # 1738[lib/setup.c:254] rand seed 1696451931
> TAP version 13
> ok 1 self-connect(same keyids): connect TCPAOGood 0 => 24
> ok 2 self-connect(different keyids): connect TCPAOGood 26 => 50
> ok 3 self-connect(restore): connect TCPAOGood 52 => 97
> ok 4 self-connect(restore, different keyids): connect TCPAOGood 99 => 144
> # Totals: pass:4 fail:0 xfail:0 xpass:0 skip:0 error:0
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/net/tcp_ao/Makefile

@@ -5,6 +5,7 @@ TEST_BOTH_AF += connect-deny
 TEST_BOTH_AF += icmps-accept icmps-discard
 TEST_BOTH_AF += restore
 TEST_BOTH_AF += rst
+TEST_BOTH_AF += self-connect
 TEST_BOTH_AF += seq-ext
 TEST_BOTH_AF += setsockopt-closed
 TEST_BOTH_AF += unsigned-md5

tools/testing/selftests/net/tcp_ao/self-connect.c

+// SPDX-License-Identifier: GPL-2.0
+/* Author: Dmitry Safonov <dima@arista.com> */
+#include <inttypes.h>
+#include "aolib.h"
+
+static union tcp_addr local_addr;
+
+static void __setup_lo_intf(const char *lo_intf,
+			    const char *addr_str, uint8_t prefix)
+{
+	if (inet_pton(TEST_FAMILY, addr_str, &local_addr) != 1)
+		test_error("Can't convert local ip address");
+
+	if (ip_addr_add(lo_intf, TEST_FAMILY, local_addr, prefix))
+		test_error("Failed to add %s ip address", lo_intf);
+
+	if (link_set_up(lo_intf))
+		test_error("Failed to bring %s up", lo_intf);
+}
+
+static void setup_lo_intf(const char *lo_intf)
+{
+#ifdef IPV6_TEST
+	__setup_lo_intf(lo_intf, "::1", 128);
+#else
+	__setup_lo_intf(lo_intf, "127.0.0.1", 8);
+#endif
+}
+
+static void tcp_self_connect(const char *tst, unsigned int port,
+			     bool different_keyids, bool check_restore)
+{
+	uint64_t before_challenge_ack, after_challenge_ack;
+	uint64_t before_syn_challenge, after_syn_challenge;
+	struct tcp_ao_counters before_ao, after_ao;
+	uint64_t before_aogood, after_aogood;
+	struct netstat *ns_before, *ns_after;
+	const size_t nr_packets = 20;
+	struct tcp_ao_repair ao_img;
+	struct tcp_sock_state img;
+	sockaddr_af addr;
+	int sk;
+
+	tcp_addr_to_sockaddr_in(&addr, &local_addr, htons(port));
+
+	sk = socket(test_family, SOCK_STREAM, IPPROTO_TCP);
+	if (sk < 0)
+		test_error("socket()");
+
+	if (different_keyids) {
+		if (test_add_key(sk, DEFAULT_TEST_PASSWORD, local_addr, -1, 5, 7))
+			test_error("setsockopt(TCP_AO_ADD_KEY)");
+		if (test_add_key(sk, DEFAULT_TEST_PASSWORD, local_addr, -1, 7, 5))
+			test_error("setsockopt(TCP_AO_ADD_KEY)");
+	} else {
+		if (test_add_key(sk, DEFAULT_TEST_PASSWORD, local_addr, -1, 100, 100))
+			test_error("setsockopt(TCP_AO_ADD_KEY)");
+	}
+
+	if (bind(sk, (struct sockaddr *)&addr, sizeof(addr)) < 0)
+		test_error("bind()");
+
+	ns_before = netstat_read();
+	before_aogood = netstat_get(ns_before, "TCPAOGood", NULL);
+	before_challenge_ack = netstat_get(ns_before, "TCPChallengeACK", NULL);
+	before_syn_challenge = netstat_get(ns_before, "TCPSYNChallenge", NULL);
+	if (test_get_tcp_ao_counters(sk, &before_ao))
+		test_error("test_get_tcp_ao_counters()");
+
+	if (__test_connect_socket(sk, "lo", (struct sockaddr *)&addr,
+				  sizeof(addr), TEST_TIMEOUT_SEC) < 0) {
+		ns_after = netstat_read();
+		netstat_print_diff(ns_before, ns_after);
+		test_error("failed to connect()");
+	}
+
+	if (test_client_verify(sk, 100, nr_packets, TEST_TIMEOUT_SEC)) {
+		test_fail("%s: tcp connection verify failed", tst);
+		close(sk);
+		return;
+	}
+
+	ns_after = netstat_read();
+	after_aogood = netstat_get(ns_after, "TCPAOGood", NULL);
+	after_challenge_ack = netstat_get(ns_after, "TCPChallengeACK", NULL);
+	after_syn_challenge = netstat_get(ns_after, "TCPSYNChallenge", NULL);
+	if (test_get_tcp_ao_counters(sk, &after_ao))
+		test_error("test_get_tcp_ao_counters()");
+	if (!check_restore) {
+		/* to debug: netstat_print_diff(ns_before, ns_after); */
+		netstat_free(ns_before);
+	}
+	netstat_free(ns_after);
+
+	if (after_aogood <= before_aogood) {
+		test_fail("%s: TCPAOGood counter mismatch: %zu <= %zu",
+			  tst, after_aogood, before_aogood);
+		close(sk);
+		return;
+	}
+	if (after_challenge_ack <= before_challenge_ack ||
+	    after_syn_challenge <= before_syn_challenge) {
+		/*
+		 * It's also meant to test simultaneous open, so check
+		 * these counters as well.
+		 */
+		test_fail("%s: Didn't challenge SYN or ACK: %zu <= %zu OR %zu <= %zu",
+			  tst, after_challenge_ack, before_challenge_ack,
+			  after_syn_challenge, before_syn_challenge);
+		close(sk);
+		return;
+	}
+
+	if (test_tcp_ao_counters_cmp(tst, &before_ao, &after_ao, TEST_CNT_GOOD)) {
+		close(sk);
+		return;
+	}
+
+	if (!check_restore) {
+		test_ok("%s: connect TCPAOGood %" PRIu64 " => %" PRIu64,
+				tst, before_aogood, after_aogood);
+		close(sk);
+		return;
+	}
+
+	test_enable_repair(sk);
+	test_sock_checkpoint(sk, &img, &addr);
+#ifdef IPV6_TEST
+	addr.sin6_port = htons(port + 1);
+#else
+	addr.sin_port = htons(port + 1);
+#endif
+	test_ao_checkpoint(sk, &ao_img);
+	test_kill_sk(sk);
+
+	sk = socket(test_family, SOCK_STREAM, IPPROTO_TCP);
+	if (sk < 0)
+		test_error("socket()");
+
+	test_enable_repair(sk);
+	__test_sock_restore(sk, "lo", &img, &addr, &addr, sizeof(addr));
+	if (different_keyids) {
+		if (test_add_repaired_key(sk, DEFAULT_TEST_PASSWORD, 0,
+					  local_addr, -1, 7, 5))
+			test_error("setsockopt(TCP_AO_ADD_KEY)");
+		if (test_add_repaired_key(sk, DEFAULT_TEST_PASSWORD, 0,
+					  local_addr, -1, 5, 7))
+			test_error("setsockopt(TCP_AO_ADD_KEY)");
+	} else {
+		if (test_add_repaired_key(sk, DEFAULT_TEST_PASSWORD, 0,
+					  local_addr, -1, 100, 100))
+			test_error("setsockopt(TCP_AO_ADD_KEY)");
+	}
+	test_ao_restore(sk, &ao_img);
+	test_disable_repair(sk);
+	test_sock_state_free(&img);
+	if (test_client_verify(sk, 100, nr_packets, TEST_TIMEOUT_SEC)) {
+		test_fail("%s: tcp connection verify failed", tst);
+		close(sk);
+		return;
+	}
+	ns_after = netstat_read();
+	after_aogood = netstat_get(ns_after, "TCPAOGood", NULL);
+	/* to debug: netstat_print_diff(ns_before, ns_after); */
+	netstat_free(ns_before);
+	netstat_free(ns_after);
+	close(sk);
+	if (after_aogood <= before_aogood) {
+		test_fail("%s: TCPAOGood counter mismatch: %zu <= %zu",
+			  tst, after_aogood, before_aogood);
+		return;
+	}
+	test_ok("%s: connect TCPAOGood %" PRIu64 " => %" PRIu64,
+			tst, before_aogood, after_aogood);
+}
+
+static void *client_fn(void *arg)
+{
+	unsigned int port = test_server_port;
+
+	setup_lo_intf("lo");
+
+	tcp_self_connect("self-connect(same keyids)", port++, false, false);
+	tcp_self_connect("self-connect(different keyids)", port++, true, false);
+	tcp_self_connect("self-connect(restore)", port, false, true);
+	port += 2;
+	tcp_self_connect("self-connect(restore, different keyids)", port, true, true);
+	port += 2;
+
+	return NULL;
+}
+
+int main(int argc, char *argv[])
+{
+	test_init(4, client_fn, NULL);
+	return 0;
+}