net: Add support for IPv4_MULTICAST_LOOP in net_context

Add support for the IP_MULTICAST_LOOP socket option to control
multicast packet loopback.

Signed-off-by: AbdElRahman Khalifa <abdelrahman.5alifa@gmail.com>

include/zephyr/net/net_context.h

@@ -394,6 +394,7 @@ __net_socket struct net_context {
 		/** Flag to enable/disable multicast loop */
 		union {
 			bool ipv6_mcast_loop;  /**< IPv6 multicast loop */
+			bool ipv4_mcast_loop;  /**< IPv4 multicast loop */
 		};
 #endif /* CONFIG_NET_IPV6 || CONFIG_NET_IPV4 */
 
@@ -843,6 +844,38 @@ static inline void net_context_set_ipv4_mcast_ttl(struct net_context *context,
 	context->ipv4_mcast_ttl = ttl;
 }
 
+#if defined(CONFIG_NET_IPV4)
+/**
+ * @brief Get IPv4 multicast loop value for this context.
+ *
+ * @details This function returns the IPv4 multicast loop value
+ *	    that is set to this context.
+ *
+ * @param context Network context.
+ *
+ * @return IPv4 multicast loop value
+ */
+static inline bool net_context_get_ipv4_mcast_loop(struct net_context *context)
+{
+	return context->options.ipv4_mcast_loop;
+}
+
+/**
+ * @brief Set IPv4 multicast loop value for this context.
+ *
+ * @details This function sets the IPv4 multicast loop value for
+ *	    this context.
+ *
+ * @param context Network context.
+ * @param ipv4_mcast_loop IPv4 multicast loop value.
+ */
+static inline void net_context_set_ipv4_mcast_loop(struct net_context *context,
+						   bool ipv4_mcast_loop)
+{
+	context->options.ipv4_mcast_loop = ipv4_mcast_loop;
+}
+#endif
+
 /**
  * @brief Get IPv6 hop limit value for this context.
  *
@@ -1365,6 +1398,7 @@ enum net_context_option {
 	NET_OPT_MTU               = 20, /**< IPv4 socket path MTU */
 	NET_OPT_LOCAL_PORT_RANGE  = 21, /**< Clamp local port range */
 	NET_OPT_IPV6_MCAST_LOOP	  = 22, /**< IPV6 multicast loop */
+	NET_OPT_IPV4_MCAST_LOOP	  = 23, /**< IPV4 multicast loop */
 };
 
 /**

include/zephyr/net/socket.h

@@ -965,6 +965,8 @@ struct in_pktinfo {
 #define IP_MULTICAST_IF 32
 /** Set IPv4 multicast TTL value. */
 #define IP_MULTICAST_TTL 33
+/** Set IPv4 multicast loop value. */
+#define IP_MULTICAST_LOOP 34
 /** Join IPv4 multicast group. */
 #define IP_ADD_MEMBERSHIP 35
 /** Leave IPv4 multicast group. */

subsys/net/ip/Kconfig.ipv4

@@ -73,6 +73,13 @@ config NET_INITIAL_MCAST_TTL
 	  don't leave the local network unless the application explicitly
 	  requests it.
 
+config NET_INITIAL_IPV4_MCAST_LOOP
+	bool "Control whether the socket sees multicast packets sent by itself"
+	default y
+	help
+	Assign initial value to IPV4_MULTICAST_LOOP in socket options,
+	if not set by the user using setsockopt().
+
 config NET_IF_MCAST_IPV4_SOURCE_COUNT
 	int "Max number of IPv4 sources per mcast address to be included or excluded"
 	default 1

subsys/net/ip/net_context.c

@@ -566,6 +566,10 @@ int net_context_get(sa_family_t family, enum net_sock_type type, uint16_t proto,
 #if defined(CONFIG_NET_IPV4_MAPPING_TO_IPV6)
 		/* By default IPv4 and IPv6 are in different port spaces */
 		contexts[i].options.ipv6_v6only = true;
+#endif
+#if defined(CONFIG_NET_IPV4)
+		contexts[i].options.ipv4_mcast_loop =
+			IS_ENABLED(CONFIG_NET_INITIAL_IPV4_MCAST_LOOP);
 #endif
 		if (IS_ENABLED(CONFIG_NET_IP)) {
 			(void)memset(&contexts[i].remote, 0, sizeof(struct sockaddr));
@@ -1783,6 +1787,19 @@ static int get_context_mcast_ttl(struct net_context *context,
 #endif
 }
 
+static int get_context_ipv4_mcast_loop(struct net_context *context,
+				  void *value, size_t *len)
+{
+#if defined(CONFIG_NET_IPV4)
+	return get_bool_option(context->options.ipv4_mcast_loop, value, len);
+#else
+	ARG_UNUSED(context);
+	ARG_UNUSED(value);
+	ARG_UNUSED(len);
+	return -ENOTSUP;
+#endif
+}
+
 static int get_context_mcast_hop_limit(struct net_context *context,
 				       void *value, size_t *len)
 {
@@ -3293,6 +3310,20 @@ static int set_context_mcast_ttl(struct net_context *context,
 #endif
 }
 
+static int set_context_ipv4_mcast_loop(struct net_context *context,
+				       const void *value, size_t len)
+{
+#if defined(CONFIG_NET_IPV4)
+	return set_bool_option(&context->options.ipv4_mcast_loop, value, len);
+#else
+	ARG_UNUSED(context);
+	ARG_UNUSED(value);
+	ARG_UNUSED(len);
+
+	return -ENOTSUP;
+#endif
+}
+
 static int set_context_mcast_hop_limit(struct net_context *context,
 				       const void *value, size_t len)
 {
@@ -3688,6 +3719,9 @@ int net_context_set_option(struct net_context *context,
 	case NET_OPT_IPV6_MCAST_LOOP:
 		ret = set_context_ipv6_mcast_loop(context, value, len);
 		break;
+	case NET_OPT_IPV4_MCAST_LOOP:
+		ret = set_context_ipv4_mcast_loop(context, value, len);
+		break;
 	}
 
 	k_mutex_unlock(&context->lock);
@@ -3776,6 +3810,9 @@ int net_context_get_option(struct net_context *context,
 	case NET_OPT_IPV6_MCAST_LOOP:
 		ret = get_context_ipv6_mcast_loop(context, value, len);
 		break;
+	case NET_OPT_IPV4_MCAST_LOOP:
+		ret = get_context_ipv4_mcast_loop(context, value, len);
+		break;
 	}
 
 	k_mutex_unlock(&context->lock);

subsys/net/ip/net_core.c

@@ -366,6 +366,34 @@ drop:
 	return ret;
 }
 
+#if defined(CONFIG_NET_IPV4) || defined(CONFIG_NET_IPV6)
+static inline bool process_multicast(struct net_pkt *pkt)
+{
+	struct net_context *ctx = net_pkt_context(pkt);
+	sa_family_t family = net_pkt_family(pkt);
+
+	if (ctx == NULL) {
+		return false;
+	}
+
+#if defined(CONFIG_NET_IPV4)
+	if (family == AF_INET) {
+		const struct in_addr *dst = (const struct in_addr *)&NET_IPV4_HDR(pkt)->dst;
+
+		return net_ipv4_is_addr_mcast(dst) && net_context_get_ipv4_mcast_loop(ctx);
+	}
+#endif
+#if defined(CONFIG_NET_IPV6)
+	if (family == AF_INET6) {
+		const struct in6_addr *dst = (const struct in6_addr *)&NET_IPV6_HDR(pkt)->dst;
+
+		return net_ipv6_is_addr_mcast(dst) && net_context_get_ipv6_mcast_loop(ctx);
+	}
+#endif
+	return false;
+}
+#endif
+
 int net_try_send_data(struct net_pkt *pkt, k_timeout_t timeout)
 {
 	int status;
@@ -410,26 +438,31 @@ int net_try_send_data(struct net_pkt *pkt, k_timeout_t timeout)
 		goto err;
 	}
 
+#if defined(CONFIG_NET_IPV4) || defined(CONFIG_NET_IPV6)
+	if (process_multicast(pkt)) {
+		struct net_pkt *clone = net_pkt_clone(pkt, K_NO_WAIT);
+
+		if (clone != NULL) {
+			net_pkt_set_iface(clone, net_pkt_iface(pkt));
+			if (net_recv_data(net_pkt_iface(clone), clone) < 0) {
+				if (IS_ENABLED(CONFIG_NET_STATISTICS)) {
+					switch (net_pkt_family(pkt)) {
+#if defined(CONFIG_NET_IPV4)
+					case AF_INET:
+						net_stats_update_ipv4_sent(net_pkt_iface(pkt));
+						break;
+#endif
 #if defined(CONFIG_NET_IPV6)
-	if (net_pkt_family(pkt) == AF_INET6) {
+					case AF_INET6:
-		const struct in6_addr *dest = (const struct in6_addr *)&NET_IPV6_HDR(pkt)->dst;
+						net_stats_update_ipv6_sent(net_pkt_iface(pkt));
-		struct net_context *ctx = net_pkt_context(pkt);
+						break;
-
+#endif
-		if (net_ipv6_is_addr_mcast(dest) && ctx != NULL &&
-		    net_context_get_ipv6_mcast_loop(ctx)) {
-			struct net_pkt *clone = net_pkt_clone(pkt, K_NO_WAIT);
-
-			if (clone != NULL) {
-				net_pkt_set_iface(clone, net_pkt_iface(pkt));
-				if (net_recv_data(net_pkt_iface(clone), clone) < 0) {
-					if (IS_ENABLED(CONFIG_NET_STATISTICS)) {
-						net_stats_update_ipv6_drop(net_pkt_iface(pkt));
 					}
-					net_pkt_unref(clone);
 				}
-			} else {
+				net_pkt_unref(clone);
-				NET_DBG("Failed to clone multicast packet");
 			}
+		} else {
+			NET_DBG("Failed to clone multicast packet");
 		}
 	}
 #endif

subsys/net/lib/sockets/sockets_inet.c

@@ -1974,6 +1974,18 @@ int zsock_getsockopt_ctx(struct net_context *ctx, int level, int optname,
 			}
 
 			break;
+#if defined(CONFIG_NET_IPV4)
+		case IP_MULTICAST_LOOP:
+			ret = net_context_get_option(ctx,
+						     NET_OPT_IPV4_MCAST_LOOP,
+						     optval, optlen);
+			if (ret < 0) {
+				errno  = -ret;
+				return -1;
+			}
+
+			return 0;
+#endif
 		}
 
 		break;
@@ -2604,6 +2616,18 @@ int zsock_setsockopt_ctx(struct net_context *ctx, int level, int optname,
 			}
 
 			break;
+#if defined(CONFIG_NET_IPV4)
+		case IP_MULTICAST_LOOP:
+			ret = net_context_set_option(ctx,
+						     NET_OPT_IPV4_MCAST_LOOP,
+						     optval, optlen);
+			if (ret < 0) {
+				errno  = -ret;
+				return -1;
+			}
+
+			return 0;
+#endif
 		}
 
 		break;