net: ip: Add iface IPv4/IPv6 multicast foreach handlers

Add helper functions to iterate IPv4/IPv6 multicast addresses.

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

include/zephyr/net/net_if.h

@@ -1412,6 +1412,29 @@ struct net_if_mcast_addr *net_if_ipv6_maddr_add(struct net_if *iface,
  */
 bool net_if_ipv6_maddr_rm(struct net_if *iface, const struct in6_addr *addr);
 
+/**
+ * @typedef net_if_ip_maddr_cb_t
+ * @brief Callback used while iterating over network interface multicast IP addresses
+ *
+ * @param iface Pointer to the network interface the address belongs to
+ * @param maddr Pointer to current multicast IP address
+ * @param user_data A valid pointer to user data or NULL
+ */
+typedef void (*net_if_ip_maddr_cb_t)(struct net_if *iface,
+				     struct net_if_mcast_addr *maddr,
+				     void *user_data);
+
+/**
+ * @brief Go through all IPv6 multicast addresses on a network interface and call
+ * callback for each used address.
+ *
+ * @param iface Pointer to the network interface
+ * @param cb User-supplied callback function to call
+ * @param user_data User specified data
+ */
+void net_if_ipv6_maddr_foreach(struct net_if *iface, net_if_ip_maddr_cb_t cb,
+			       void *user_data);
+
 /**
  * @brief Check if this IPv6 multicast address belongs to a specific interface
  * or one of the interfaces.
@@ -2099,6 +2122,17 @@ struct net_if_mcast_addr *net_if_ipv4_maddr_add(struct net_if *iface,
  */
 bool net_if_ipv4_maddr_rm(struct net_if *iface, const struct in_addr *addr);
 
+/**
+ * @brief Go through all IPv4 multicast addresses on a network interface and call
+ * callback for each used address.
+ *
+ * @param iface Pointer to the network interface
+ * @param cb User-supplied callback function to call
+ * @param user_data User specified data
+ */
+void net_if_ipv4_maddr_foreach(struct net_if *iface, net_if_ip_maddr_cb_t cb,
+			       void *user_data);
+
 /**
  * @brief Check if this IPv4 multicast address belongs to a specific interface
  * or one of the interfaces.

subsys/net/ip/net_if.c

@@ -2123,6 +2123,33 @@ bool net_if_ipv6_maddr_rm(struct net_if *iface, const struct in6_addr *addr)
 	return ret;
 }
 
+void net_if_ipv6_maddr_foreach(struct net_if *iface, net_if_ip_maddr_cb_t cb,
+			       void *user_data)
+{
+	struct net_if_ipv6 *ipv6;
+
+	NET_ASSERT(iface);
+	NET_ASSERT(cb);
+
+	net_if_lock(iface);
+
+	ipv6 = iface->config.ip.ipv6;
+	if (!ipv6) {
+		goto out;
+	}
+
+	for (int i = 0; i < NET_IF_MAX_IPV6_MADDR; i++) {
+		if (!ipv6->mcast[i].is_used) {
+			continue;
+		}
+
+		cb(iface, &ipv6->mcast[i], user_data);
+	}
+
+out:
+	net_if_unlock(iface);
+}
+
 struct net_if_mcast_addr *net_if_ipv6_maddr_lookup(const struct in6_addr *maddr,
 						   struct net_if **ret)
 {
@@ -4136,6 +4163,33 @@ bool net_if_ipv4_maddr_rm(struct net_if *iface, const struct in_addr *addr)
 	return ret;
 }
 
+void net_if_ipv4_maddr_foreach(struct net_if *iface, net_if_ip_maddr_cb_t cb,
+			       void *user_data)
+{
+	struct net_if_ipv4 *ipv4;
+
+	NET_ASSERT(iface);
+	NET_ASSERT(cb);
+
+	net_if_lock(iface);
+
+	ipv4 = iface->config.ip.ipv4;
+	if (!ipv4) {
+		goto out;
+	}
+
+	for (int i = 0; i < NET_IF_MAX_IPV4_MADDR; i++) {
+		if (!ipv4->mcast[i].is_used) {
+			continue;
+		}
+
+		cb(iface, &ipv4->mcast[i], user_data);
+	}
+
+out:
+	net_if_unlock(iface);
+}
+
 struct net_if_mcast_addr *net_if_ipv4_maddr_lookup(const struct in_addr *maddr,
 						   struct net_if **ret)
 {