selftests/bpf: Test sockmap update when socket has ULP

Cover the scenario when we cannot insert a socket into the sockmap, because
it has it is using ULP. Failed insert should not have any effect on the ULP
state. This is a regression test.
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/r/20220623091231.417138-1-jakub@cloudflare.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -4,6 +4,7 @@
  * Tests for sockmap/sockhash holding kTLS sockets.
  */
 
+#include <netinet/tcp.h>
 #include "test_progs.h"
 
 #define MAX_TEST_NAME 80
@@ -92,9 +93,78 @@ static void test_sockmap_ktls_disconnect_after_delete(int family, int map)
 	close(srv);
 }
 
+static void test_sockmap_ktls_update_fails_when_sock_has_ulp(int family, int map)
+{
+	struct sockaddr_storage addr = {};
+	socklen_t len = sizeof(addr);
+	struct sockaddr_in6 *v6;
+	struct sockaddr_in *v4;
+	int err, s, zero = 0;
+
+	switch (family) {
+	case AF_INET:
+		v4 = (struct sockaddr_in *)&addr;
+		v4->sin_family = AF_INET;
+		break;
+	case AF_INET6:
+		v6 = (struct sockaddr_in6 *)&addr;
+		v6->sin6_family = AF_INET6;
+		break;
+	default:
+		PRINT_FAIL("unsupported socket family %d", family);
+		return;
+	}
+
+	s = socket(family, SOCK_STREAM, 0);
+	if (!ASSERT_GE(s, 0, "socket"))
+		return;
+
+	err = bind(s, (struct sockaddr *)&addr, len);
+	if (!ASSERT_OK(err, "bind"))
+		goto close;
+
+	err = getsockname(s, (struct sockaddr *)&addr, &len);
+	if (!ASSERT_OK(err, "getsockname"))
+		goto close;
+
+	err = connect(s, (struct sockaddr *)&addr, len);
+	if (!ASSERT_OK(err, "connect"))
+		goto close;
+
+	/* save sk->sk_prot and set it to tls_prots */
+	err = setsockopt(s, IPPROTO_TCP, TCP_ULP, "tls", strlen("tls"));
+	if (!ASSERT_OK(err, "setsockopt(TCP_ULP)"))
+		goto close;
+
+	/* sockmap update should not affect saved sk_prot */
+	err = bpf_map_update_elem(map, &zero, &s, BPF_ANY);
+	if (!ASSERT_ERR(err, "sockmap update elem"))
+		goto close;
+
+	/* call sk->sk_prot->setsockopt to dispatch to saved sk_prot */
+	err = setsockopt(s, IPPROTO_TCP, TCP_NODELAY, &zero, sizeof(zero));
+	ASSERT_OK(err, "setsockopt(TCP_NODELAY)");
+
+close:
+	close(s);
+}
+
+static const char *fmt_test_name(const char *subtest_name, int family,
+				 enum bpf_map_type map_type)
+{
+	const char *map_type_str = BPF_MAP_TYPE_SOCKMAP ? "SOCKMAP" : "SOCKHASH";
+	const char *family_str = AF_INET ? "IPv4" : "IPv6";
+	static char test_name[MAX_TEST_NAME];
+
+	snprintf(test_name, MAX_TEST_NAME,
+		 "sockmap_ktls %s %s %s",
+		 subtest_name, family_str, map_type_str);
+
+	return test_name;
+}
+
 static void run_tests(int family, enum bpf_map_type map_type)
 {
-	char test_name[MAX_TEST_NAME];
 	int map;
 
 	map = bpf_map_create(map_type, NULL, sizeof(int), sizeof(int), 1, NULL);
@@ -103,14 +173,10 @@ static void run_tests(int family, enum bpf_map_type map_type)
 		return;
 	}
 
-	snprintf(test_name, MAX_TEST_NAME,
-		 "sockmap_ktls disconnect_after_delete %s %s",
-		 family == AF_INET ? "IPv4" : "IPv6",
-		 map_type == BPF_MAP_TYPE_SOCKMAP ? "SOCKMAP" : "SOCKHASH");
-	if (!test__start_subtest(test_name))
-		return;
-
-	test_sockmap_ktls_disconnect_after_delete(family, map);
+	if (test__start_subtest(fmt_test_name("disconnect_after_delete", family, map_type)))
+		test_sockmap_ktls_disconnect_after_delete(family, map);
+	if (test__start_subtest(fmt_test_name("update_fails_when_sock_has_ulp", family, map_type)))
+		test_sockmap_ktls_update_fails_when_sock_has_ulp(family, map);
 
 	close(map);
 }