selftests/net: Rectify key counters checks

As the names of (struct test_key) members didn't reflect whether the key
was used for TX or RX, the verification for the counters was done
incorrectly for asymmetrical selftests.

Rename these with _tx appendix and fix checks in verify_counters().
While at it, as the checks are now correct, introduce skip_counters_checks,
which is intended for tests where it's expected that a key that was set
with setsockopt(sk, IPPROTO_TCP, TCP_AO_INFO, ...) might had no chance
of getting used on the wire.

Fixes the following failures, exposed by the previous commit:
> not ok 51 server: Check current != rnext keys set before connect(): Counter pkt_good was expected to increase 0 => 0 for key 132:5
> not ok 52 server: Check current != rnext keys set before connect(): Counter pkt_good was not expected to increase 0 => 21 for key 137:10
>
> not ok 63 server: Check current flapping back on peer's RnextKey request: Counter pkt_good was expected to increase 0 => 0 for key 132:5
> not ok 64 server: Check current flapping back on peer's RnextKey request: Counter pkt_good was not expected to increase 0 => 40 for key 137:10

Cc: Mohammad Nassiri <mnassiri@ciena.com>
Fixes: 3c3ead55 ("selftests/net: Add TCP-AO key-management test")
Signed-off-by: Dmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20240130-tcp-ao-test-key-mgmt-v2-2-d190430a6c60@arista.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/net/tcp_ao/key-management.c

@@ -417,9 +417,9 @@ struct test_key {
 		matches_vrf		: 1,
 		is_current		: 1,
 		is_rnext		: 1,
-		used_on_handshake	: 1,
-		used_after_accept	: 1,
-		used_on_client		: 1;
+		used_on_server_tx	: 1,
+		used_on_client_tx	: 1,
+		skip_counters_checks	: 1;
 };
 
 struct key_collection {
@@ -609,16 +609,14 @@ static int key_collection_socket(bool server, unsigned int port)
 				addr = &this_ip_dest;
 			sndid = key->client_keyid;
 			rcvid = key->server_keyid;
-			set_current = key->is_current;
-			set_rnext = key->is_rnext;
+			key->used_on_client_tx = set_current = key->is_current;
+			key->used_on_server_tx = set_rnext = key->is_rnext;
 		}
 
 		if (test_add_key_cr(sk, key->password, key->len,
 				    *addr, vrf, sndid, rcvid, key->maclen,
 				    key->alg, set_current, set_rnext))
 			test_key_error("setsockopt(TCP_AO_ADD_KEY)", key);
-		if (set_current || set_rnext)
-			key->used_on_handshake = 1;
 #ifdef DEBUG
 		test_print("%s [%u/%u] key: { %s, %u:%u, %u, %u:%u:%u:%u (%u)}",
 			   server ? "server" : "client", i, collection.nr_keys,
@@ -640,22 +638,22 @@ static void verify_counters(const char *tst_name, bool is_listen_sk, bool server
 	for (i = 0; i < collection.nr_keys; i++) {
 		struct test_key *key = &collection.keys[i];
 		uint8_t sndid, rcvid;
-		bool was_used;
+		bool rx_cnt_expected;
 
+		if (key->skip_counters_checks)
+			continue;
 		if (server) {
 			sndid = key->server_keyid;
 			rcvid = key->client_keyid;
-			if (is_listen_sk)
-				was_used = key->used_on_handshake;
-			else
-				was_used = key->used_after_accept;
+			rx_cnt_expected = key->used_on_client_tx;
 		} else {
 			sndid = key->client_keyid;
 			rcvid = key->server_keyid;
-			was_used = key->used_on_client;
+			rx_cnt_expected = key->used_on_server_tx;
 		}
 
-		test_tcp_ao_key_counters_cmp(tst_name, a, b, was_used,
+		test_tcp_ao_key_counters_cmp(tst_name, a, b,
+					     rx_cnt_expected ? TEST_CNT_KEY_GOOD : 0,
 					     sndid, rcvid);
 	}
 	test_tcp_ao_counters_free(a);
@@ -916,9 +914,8 @@ static int run_client(const char *tst_name, unsigned int port,
 		current_index = nr_keys - 1;
 	if (rnext_index < 0)
 		rnext_index = nr_keys - 1;
-	collection.keys[current_index].used_on_handshake = 1;
-	collection.keys[rnext_index].used_after_accept = 1;
-	collection.keys[rnext_index].used_on_client = 1;
+	collection.keys[current_index].used_on_client_tx = 1;
+	collection.keys[rnext_index].used_on_server_tx = 1;
 
 	synchronize_threads(); /* 3: accepted => send data */
 	if (test_client_verify(sk, msg_sz, msg_nr, TEST_TIMEOUT_SEC)) {
@@ -1059,7 +1056,16 @@ static void check_current_back(const char *tst_name, unsigned int port,
 		test_error("Can't change the current key");
 	if (test_client_verify(sk, msg_len, nr_packets, TEST_TIMEOUT_SEC))
 		test_fail("verify failed");
-	collection.keys[rotate_to_index].used_after_accept = 1;
+	/* There is a race here: between setting the current_key with
+	 * setsockopt(TCP_AO_INFO) and starting to send some data - there
+	 * might have been a segment received with the desired
+	 * RNext_key set. In turn that would mean that the first outgoing
+	 * segment will have the desired current_key (flipped back).
+	 * Which is what the user/test wants. As it's racy, skip checking
+	 * the counters, yet check what are the resulting current/rnext
+	 * keys on both sides.
+	 */
+	collection.keys[rotate_to_index].skip_counters_checks = 1;
 
 	end_client(tst_name, sk, nr_keys, current_index, rnext_index, &tmp);
 }
@@ -1089,7 +1095,7 @@ static void roll_over_keys(const char *tst_name, unsigned int port,
 		}
 		verify_current_rnext(tst_name, sk, -1,
 				     collection.keys[i].server_keyid);
-		collection.keys[i].used_on_client = 1;
+		collection.keys[i].used_on_server_tx = 1;
 		synchronize_threads(); /* verify current/rnext */
 	}
 	end_client(tst_name, sk, nr_keys, current_index, rnext_index, &tmp);