tests: net: iface: Test foreach multicast helper functions

Add test cases for IPv4/IPv6 foreach functions that iterate all
multicast addresses assigned to an interface.

Signed-off-by: Pieter De Gendt <pieter.degendt@basalte.be>

tests/net/iface/src/main.c

@@ -56,6 +56,7 @@ static struct in6_addr ll_addr = { { { 0xfe, 0x80, 0x43, 0xb8, 0, 0, 0, 0,
 				       0, 0, 0, 0xf2, 0xaa, 0x29, 0x02,
 				       0x04 } } };
 
+static struct in_addr inaddr_mcast = { { { 224, 0, 0, 1 } } };
 static struct in6_addr in6addr_mcast;
 
 static struct net_if *iface1;
@@ -439,6 +440,13 @@ static void *iface_setup(void)
 
 	ifaddr->addr_state = NET_ADDR_PREFERRED;
 
+	maddr = net_if_ipv4_maddr_add(iface1, &inaddr_mcast);
+	if (!maddr) {
+		DBG("Cannot add multicast IPv4 address %s\n",
+		       net_sprint_ipv4_addr(&inaddr_mcast));
+		zassert_not_null(maddr, "mcast");
+	}
+
 	net_ipv6_addr_create(&in6addr_mcast, 0xff02, 0, 0, 0, 0, 0, 0, 0x0001);
 
 	maddr = net_if_ipv6_maddr_add(iface1, &in6addr_mcast);
@@ -1174,6 +1182,34 @@ ZTEST(net_iface, test_ipv4_addr_foreach)
 	zassert_equal(count, 0, "Incorrect number of callback calls");
 }
 
+static void foreach_ipv4_maddr_check(struct net_if *iface,
+				     struct net_if_mcast_addr *if_addr,
+				     void *user_data)
+{
+	int *count = (int *)user_data;
+
+	(*count)++;
+
+	zassert_equal_ptr(iface, iface1, "Callback called on wrong interface");
+	zassert_mem_equal(&if_addr->address.in_addr, &inaddr_mcast,
+			  sizeof(struct in_addr), "Wrong IPv4 multicast address");
+}
+
+ZTEST(net_iface, test_ipv4_maddr_foreach)
+{
+	int count = 0;
+
+	/* iface1 has one IPv4 multicast address configured */
+	net_if_ipv4_maddr_foreach(iface1, foreach_ipv4_maddr_check, &count);
+	zassert_equal(count, 1, "Incorrect number of callback calls");
+
+	count = 0;
+
+	/* iface4 has no IPv4 multicast address configured */
+	net_if_ipv4_maddr_foreach(iface4, foreach_ipv4_maddr_check, &count);
+	zassert_equal(count, 0, "Incorrect number of callback calls");
+}
+
 static void foreach_ipv6_addr_check(struct net_if *iface,
 				    struct net_if_addr *if_addr,
 				    void *user_data)
@@ -1208,6 +1244,34 @@ ZTEST(net_iface, test_ipv6_addr_foreach)
 	zassert_equal(count, 0, "Incorrect number of callback calls");
 }
 
+static void foreach_ipv6_maddr_check(struct net_if *iface,
+				     struct net_if_mcast_addr *if_addr,
+				     void *user_data)
+{
+	int *count = (int *)user_data;
+
+	(*count)++;
+
+	zassert_equal_ptr(iface, iface1, "Callback called on wrong interface");
+	zassert_mem_equal(&if_addr->address.in6_addr, &in6addr_mcast, sizeof(struct in6_addr),
+			  "Wrong IPv6 multicast address");
+}
+
+ZTEST(net_iface, test_ipv6_maddr_foreach)
+{
+	int count = 0;
+
+	/* iface1 has one IPv6 multicast address configured */
+	net_if_ipv6_maddr_foreach(iface1, foreach_ipv6_maddr_check, &count);
+	zassert_equal(count, 1, "Incorrect number of callback calls");
+
+	count = 0;
+
+	/* iface4 has no IPv6 multicast address configured */
+	net_if_ipv6_maddr_foreach(iface4, foreach_ipv6_maddr_check, &count);
+	zassert_equal(count, 0, "Incorrect number of callback calls");
+}
+
 ZTEST(net_iface, test_interface_name)
 {
 	int ret;