tests: net: socket: udp: Add IP_MULTICAST_IF set/get testing

Add tests that verify that IP_MULTICAST_IF socket option
set/get works as expected.

Signed-off-by: Jukka Rissanen <[email protected]>

Author: jukkar

tests/net/socket/udp/src/main.c

@@ -949,6 +949,7 @@ static struct in6_addr my_addr3 = { { { 0x20, 0x01, 0x0d, 0xb8, 1, 0, 0, 0,
 					0, 0, 0, 0, 0, 0, 0, 0x3 } } };
 static struct in6_addr my_mcast_addr1 = { { { 0xff, 0x01, 0, 0, 0, 0, 0, 0,
 					0, 0, 0, 0, 0, 0, 0, 0x1 } } };
+static struct in_addr my_mcast_addr2 = { { { 224, 0, 0, 2 } } };
 static uint8_t server_lladdr[] = { 0x01, 0x02, 0x03, 0xff, 0xfe,
 				0x04, 0x05, 0x06 };
 static struct net_linkaddr server_link_addr = {
@@ -2671,6 +2672,259 @@ ZTEST(net_socket_udp, test_38_ipv6_multicast_ifindex)
 	loopback_enable_address_swap(true);
 }
 
+ZTEST(net_socket_udp, test_39_ipv4_multicast_ifindex)
+{
+	struct sockaddr_in saddr4 = {
+		.sin_family = AF_INET,
+		.sin_port = htons(SERVER_PORT),
+		.sin_addr = my_mcast_addr2,
+	};
+	struct sockaddr_in dst_addr = {
+		.sin_family = AF_INET,
+		.sin_port = htons(SERVER_PORT),
+		.sin_addr = my_mcast_addr2,
+	};
+	struct net_if_mcast_addr *ifmaddr;
+	struct net_if_addr *ifaddr;
+	struct in_addr addr = { 0 };
+	struct ip_mreqn mreqn;
+	struct ip_mreq mreq;
+	struct net_if *iface;
+	int server_sock;
+	size_t addrlen;
+	size_t optlen;
+	int ifindex;
+	int sock;
+	int ret;
+	int err;
+
+	net_if_foreach(iface_cb, &eth_iface);
+	zassert_not_null(eth_iface, "No ethernet interface found");
+
+	ifmaddr = net_if_ipv4_maddr_add(eth_iface, &my_mcast_addr2);
+	if (!ifmaddr) {
+		DBG("Cannot add IPv4 multicast address %s\n",
+		       net_sprint_ipv4_addr(&my_mcast_addr2));
+		zassert_not_null(ifmaddr, "mcast_addr2");
+	}
+
+	ifaddr = net_if_ipv4_addr_add(eth_iface, &my_addr2,
+				      NET_ADDR_MANUAL, 0);
+	if (!ifaddr) {
+		DBG("Cannot add IPv4 address %s\n",
+		       net_sprint_ipv4_addr(&my_addr2));
+		zassert_not_null(ifaddr, "addr2");
+	}
+
+	net_if_up(eth_iface);
+
+	/* Check that we get the default interface */
+	sock = zsock_socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+	zassert_true(sock >= 0, "Cannot create socket (%d)", -errno);
+
+	optlen = sizeof(addr);
+	ret = zsock_getsockopt(sock, IPPROTO_IP, IP_MULTICAST_IF,
+			       &addr, &optlen);
+	zexpect_equal(ret, 0, "setsockopt failed (%d)", errno);
+	zexpect_equal(optlen, sizeof(addr), "invalid optlen %d vs %d",
+		      optlen, sizeof(addr));
+	ifindex = net_if_get_by_iface(net_if_get_default());
+	ret = net_if_ipv4_addr_lookup_by_index(&addr);
+	zexpect_equal(ret, ifindex,
+		      "getsockopt multicast ifindex (expected %d got %d)",
+		      ifindex, ret);
+
+	ret = zsock_close(sock);
+	zassert_equal(sock, 0, "Cannot close socket (%d)", -errno);
+
+	/* Check failure for IPv6 socket */
+	sock = zsock_socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
+	zassert_true(sock >= 0, "Cannot create socket (%d)", -errno);
+
+	optlen = 0U;
+	ret = zsock_getsockopt(sock, IPPROTO_IP, IP_MULTICAST_IF,
+			       &addr, &optlen);
+	err = -errno;
+	zexpect_equal(ret, -1, "setsockopt failed (%d)", errno);
+	zexpect_equal(err, -EAFNOSUPPORT, "setsockopt failed (%d)", errno);
+	zexpect_equal(optlen, 0U, "setsockopt optlen (%d)", optlen);
+
+	ret = zsock_close(sock);
+	zassert_equal(sock, 0, "Cannot close socket (%d)", -errno);
+
+	/* Check that we can set the interface */
+	sock = zsock_socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+	zassert_true(sock >= 0, "Cannot create socket (%d)", -errno);
+
+	/* Clear any existing interface value by setting it to 0 */
+	optlen = sizeof(mreqn);
+	mreqn.imr_ifindex = 0;
+	mreqn.imr_address.s_addr = 0;
+
+	ret = zsock_setsockopt(sock, IPPROTO_IP, IP_MULTICAST_IF,
+			       &mreqn, optlen);
+	err = -errno;
+	zexpect_equal(ret, 0, "setsockopt failed (%d)", err);
+
+	/* Verify that we get the empty value */
+	optlen = sizeof(addr);
+	ret = zsock_getsockopt(sock, IPPROTO_IP, IP_MULTICAST_IF,
+			       &addr, &optlen);
+	err = -errno;
+	zexpect_equal(ret, 0, "setsockopt failed (%d)", err);
+	zexpect_equal(optlen, sizeof(addr), "setsockopt optlen (%d)", optlen);
+
+	/* Set the output multicast packet interface to the default interface */
+	optlen = sizeof(mreqn);
+	mreqn.imr_ifindex = net_if_get_by_iface(net_if_get_default());
+	mreqn.imr_address.s_addr = 0;
+
+	ret = zsock_setsockopt(sock, IPPROTO_IP, IP_MULTICAST_IF,
+			       &mreqn, optlen);
+	err = -errno;
+	zexpect_equal(ret, 0, "setsockopt failed (%d)", err);
+
+	/* Verify that we get the default interface */
+	optlen = sizeof(addr);
+	memset(&addr, 0, sizeof(addr));
+	ret = zsock_getsockopt(sock, IPPROTO_IP, IP_MULTICAST_IF,
+			       &addr, &optlen);
+	err = -errno;
+	zexpect_equal(ret, 0, "setsockopt failed (%d)", err);
+	zexpect_equal(optlen, sizeof(addr), "setsockopt optlen (%d)", optlen);
+
+	ifaddr = net_if_ipv4_addr_lookup(&addr, &iface);
+	zexpect_not_null(ifaddr, "Address %s not found",
+			 net_sprint_ipv4_addr(&addr));
+	zexpect_equal(net_if_get_by_iface(iface),
+		      net_if_get_by_iface(net_if_get_default()),
+		      "Invalid interface %d vs %d",
+		      net_if_get_by_iface(iface),
+		      net_if_get_by_iface(net_if_get_default()));
+
+	/* Now send a packet and verify that it is sent via the default
+	 * interface instead of the Ethernet interface.
+	 */
+	server_sock = prepare_listen_sock_udp_v4(&saddr4);
+	zassert_not_equal(server_sock, -1, "Cannot create server socket (%d)", -errno);
+
+	test_started = true;
+	loopback_enable_address_swap(false);
+
+	ret = zsock_sendto(sock, TEST_STR_SMALL, sizeof(TEST_STR_SMALL) - 1, 0,
+			   (struct sockaddr *)&dst_addr, sizeof(dst_addr));
+	zexpect_equal(ret, STRLEN(TEST_STR_SMALL),
+		      "invalid send len (was %d expected %d) (%d)",
+		      ret, STRLEN(TEST_STR_SMALL), -errno);
+
+	/* Test that the sent data is received from Ethernet interface. */
+	addrlen = sizeof(saddr4);
+	ret = zsock_recvfrom(server_sock, rx_buf, sizeof(rx_buf),
+			     0, (struct sockaddr *)&saddr4, &addrlen);
+	zexpect_true(ret >= 0, "recvfrom fail");
+	zexpect_equal(ret, strlen(TEST_STR_SMALL),
+		      "unexpected received bytes");
+	zexpect_mem_equal(rx_buf, TEST_STR_SMALL, sizeof(TEST_STR_SMALL) - 1,
+			  "wrong data");
+
+	/* Clear the old interface value by setting it to 0 */
+	optlen = sizeof(mreqn);
+	mreqn.imr_ifindex = 0;
+	mreqn.imr_address.s_addr = 0;
+
+	ret = zsock_setsockopt(sock, IPPROTO_IP, IP_MULTICAST_IF,
+			       &mreqn, optlen);
+	err = -errno;
+	zexpect_equal(ret, 0, "setsockopt failed (%d)", err);
+
+	/* Then do it the other way around, set the address but leave the
+	 * interface number unassigned.
+	 */
+	optlen = sizeof(mreqn);
+	mreqn.imr_ifindex = 0;
+
+	/* Get the address of default interface and set it as a target
+	 * interface.
+	 */
+	ifaddr = net_if_ipv4_addr_get_first_by_index(net_if_get_by_iface(net_if_get_default()));
+	zexpect_not_null(ifaddr, "No address found for interface %d",
+			 net_if_get_by_iface(net_if_get_default()));
+	mreqn.imr_address.s_addr = ifaddr->address.in_addr.s_addr;
+
+	ret = zsock_setsockopt(sock, IPPROTO_IP, IP_MULTICAST_IF,
+			       &mreqn, optlen);
+	zexpect_equal(ret, 0, "setsockopt failed (%d)", errno);
+
+	/* Verify that we get the default interface address */
+	optlen = sizeof(struct in_addr);
+	ret = zsock_getsockopt(sock, IPPROTO_IP, IP_MULTICAST_IF,
+			       &addr, &optlen);
+	err = -errno;
+	zexpect_equal(ret, 0, "setsockopt failed (%d)", err);
+	zexpect_equal(optlen, sizeof(struct in_addr), "setsockopt optlen (%d)", optlen);
+	ret = net_if_ipv4_addr_lookup_by_index(&addr);
+	zexpect_equal(ret, net_if_get_by_iface(net_if_get_default()),
+		      "getsockopt multicast ifindex (expected %d got %d)",
+		      net_if_get_by_iface(net_if_get_default()), ret);
+	zexpect_equal(ifaddr->address.in_addr.s_addr,
+		      addr.s_addr,
+		      "getsockopt iface address mismatch (expected %s got %s)",
+		      net_sprint_ipv4_addr(&ifaddr->address.in_addr),
+		      net_sprint_ipv4_addr(&addr));
+
+	ret = zsock_sendto(sock, TEST_STR_SMALL, sizeof(TEST_STR_SMALL) - 1, 0,
+			   (struct sockaddr *)&dst_addr, sizeof(dst_addr));
+	zexpect_equal(ret, STRLEN(TEST_STR_SMALL),
+		      "invalid send len (was %d expected %d) (%d)",
+		      ret, STRLEN(TEST_STR_SMALL), -errno);
+
+	/* Test that the sent data is received from default interface. */
+	addrlen = sizeof(saddr4);
+	ret = zsock_recvfrom(server_sock, rx_buf, sizeof(rx_buf),
+			     0, (struct sockaddr *)&saddr4, &addrlen);
+	zexpect_true(ret >= 0, "recvfrom fail");
+	zexpect_equal(ret, strlen(TEST_STR_SMALL),
+		      "unexpected received bytes");
+	zexpect_mem_equal(rx_buf, TEST_STR_SMALL, sizeof(TEST_STR_SMALL) - 1,
+			  "wrong data");
+
+	/* Then use mreq structure to set the interface */
+	optlen = sizeof(mreq);
+	ifaddr = net_if_ipv4_addr_get_first_by_index(net_if_get_by_iface(net_if_get_default()));
+	zexpect_not_null(ifaddr, "No address found for interface %d",
+			 net_if_get_by_iface(net_if_get_default()));
+	mreq.imr_interface.s_addr = ifaddr->address.in_addr.s_addr;
+
+	ret = zsock_setsockopt(sock, IPPROTO_IP, IP_MULTICAST_IF,
+			       &mreq, optlen);
+	zexpect_equal(ret, 0, "setsockopt failed (%d)", errno);
+
+	ret = zsock_sendto(sock, TEST_STR_SMALL, sizeof(TEST_STR_SMALL) - 1, 0,
+			   (struct sockaddr *)&dst_addr, sizeof(dst_addr));
+	zexpect_equal(ret, STRLEN(TEST_STR_SMALL),
+		      "invalid send len (was %d expected %d) (%d)",
+		      ret, STRLEN(TEST_STR_SMALL), -errno);
+
+	/* Test that the sent data is received from default interface. */
+	addrlen = sizeof(saddr4);
+	ret = zsock_recvfrom(server_sock, rx_buf, sizeof(rx_buf),
+			     0, (struct sockaddr *)&saddr4, &addrlen);
+	zexpect_true(ret >= 0, "recvfrom fail");
+	zexpect_equal(ret, strlen(TEST_STR_SMALL),
+		      "unexpected received bytes");
+	zexpect_mem_equal(rx_buf, TEST_STR_SMALL, sizeof(TEST_STR_SMALL) - 1,
+			  "wrong data");
+
+	ret = zsock_close(sock);
+	zassert_equal(ret, 0, "Cannot close socket (%d)", -errno);
+
+	ret = zsock_close(server_sock);
+	zassert_equal(ret, 0, "Cannot close socket (%d)", -errno);
+
+	test_started = false;
+	loopback_enable_address_swap(true);
+}
+
 static void after(void *arg)
 {
 	ARG_UNUSED(arg);