Add multicast support to udp component (#8051)

esphome/components/network/ip_address.h

@@ -49,6 +49,7 @@ struct IPAddress {
   }
   IPAddress(const std::string &in_address) { inet_aton(in_address.c_str(), &ip_addr_); }
   IPAddress(const ip_addr_t *other_ip) { ip_addr_ = *other_ip; }
+  std::string str() const { return str_lower_case(inet_ntoa(ip_addr_)); }
 #else
   IPAddress() { ip_addr_set_zero(&ip_addr_); }
   IPAddress(uint8_t first, uint8_t second, uint8_t third, uint8_t fourth) {
@@ -119,6 +120,7 @@ struct IPAddress {
   bool is_set() { return !ip_addr_isany(&ip_addr_); }  // NOLINT(readability-simplify-boolean-expr)
   bool is_ip4() { return IP_IS_V4(&ip_addr_); }
   bool is_ip6() { return IP_IS_V6(&ip_addr_); }
+  bool is_multicast() { return ip_addr_ismulticast(&ip_addr_); }
   std::string str() const { return str_lower_case(ipaddr_ntoa(&ip_addr_)); }
   bool operator==(const IPAddress &other) const { return ip_addr_cmp(&ip_addr_, &other.ip_addr_); }
   bool operator!=(const IPAddress &other) const { return !ip_addr_cmp(&ip_addr_, &other.ip_addr_); }

esphome/components/udp/__init__.py

@@ -27,6 +27,7 @@ UDPComponent = udp_ns.class_("UDPComponent", cg.PollingComponent)
 CONF_BROADCAST = "broadcast"
 CONF_BROADCAST_ID = "broadcast_id"
 CONF_ADDRESSES = "addresses"
+CONF_LISTEN_ADDRESS = "listen_address"
 CONF_PROVIDER = "provider"
 CONF_PROVIDERS = "providers"
 CONF_REMOTE_ID = "remote_id"
@@ -84,6 +85,9 @@ CONFIG_SCHEMA = cv.All(
         {
             cv.GenerateID(): cv.declare_id(UDPComponent),
             cv.Optional(CONF_PORT, default=18511): cv.port,
+            cv.Optional(
+                CONF_LISTEN_ADDRESS, default="255.255.255.255"
+            ): cv.ipv4address_multi_broadcast,
             cv.Optional(CONF_ADDRESSES, default=["255.255.255.255"]): cv.ensure_list(
                 cv.ipv4address,
             ),
@@ -154,5 +158,7 @@ async def to_code(config):
     for provider in config.get(CONF_PROVIDERS, ()):
         name = provider[CONF_NAME]
         cg.add(var.add_provider(name))
+        if (listen_address := str(config[CONF_LISTEN_ADDRESS])) != "255.255.255.255":
+            cg.add(var.set_listen_address(listen_address))
         if encryption := provider.get(CONF_ENCRYPTION):
             cg.add(var.set_provider_encryption(name, hash_encryption_key(encryption)))

esphome/components/udp/udp_component.cpp

@@ -249,6 +249,21 @@ void UDPComponent::setup() {
     server.sin_addr.s_addr = ESPHOME_INADDR_ANY;
     server.sin_port = htons(this->port_);
 
+    if (this->listen_address_.has_value()) {
+      struct ip_mreq imreq = {};
+      imreq.imr_interface.s_addr = ESPHOME_INADDR_ANY;
+      inet_aton(this->listen_address_.value().str().c_str(), &imreq.imr_multiaddr);
+      server.sin_addr.s_addr = imreq.imr_multiaddr.s_addr;
+      ESP_LOGV(TAG, "Join multicast %s", this->listen_address_.value().str().c_str());
+      err = this->listen_socket_->setsockopt(IPPROTO_IP, IP_ADD_MEMBERSHIP, &imreq, sizeof(imreq));
+      if (err < 0) {
+        ESP_LOGE(TAG, "Failed to set IP_ADD_MEMBERSHIP. Error %d", errno);
+        this->mark_failed();
+        this->status_set_error("Failed to set IP_ADD_MEMBERSHIP");
+        return;
+      }
+    }
+
     err = this->listen_socket_->bind((struct sockaddr *) &server, sizeof(server));
     if (err != 0) {
       ESP_LOGE(TAG, "Socket unable to bind: errno %d", errno);
@@ -565,6 +580,9 @@ void UDPComponent::dump_config() {
   ESP_LOGCONFIG(TAG, "  Ping-pong: %s", YESNO(this->ping_pong_enable_));
   for (const auto &address : this->addresses_)
     ESP_LOGCONFIG(TAG, "  Address: %s", address.c_str());
+  if (this->listen_address_.has_value()) {
+    ESP_LOGCONFIG(TAG, "  Listen address: %s", this->listen_address_.value().str().c_str());
+  }
 #ifdef USE_SENSOR
   for (auto sensor : this->sensors_)
     ESP_LOGCONFIG(TAG, "  Sensor: %s", sensor.id);

esphome/components/udp/udp_component.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include "esphome/core/component.h"
+#include "esphome/components/network/ip_address.h"
 #ifdef USE_SENSOR
 #include "esphome/components/sensor/sensor.h"
 #endif
@@ -69,6 +70,7 @@ class UDPComponent : public PollingComponent {
   }
 #endif
   void add_address(const char *addr) { this->addresses_.emplace_back(addr); }
+  void set_listen_address(const char *listen_addr) { this->listen_address_ = network::IPAddress(listen_addr); }
   void set_port(uint16_t port) { this->port_ = port; }
   float get_setup_priority() const override { return setup_priority::AFTER_WIFI; }
 
@@ -143,6 +145,7 @@ class UDPComponent : public PollingComponent {
   std::map<std::string, std::map<std::string, binary_sensor::BinarySensor *>> remote_binary_sensors_{};
 #endif
 
+  optional<network::IPAddress> listen_address_{};
   std::map<std::string, Provider> providers_{};
   std::vector<uint8_t> ping_header_{};
   std::vector<uint8_t> header_{};

esphome/config_validation.py

@@ -1168,6 +1168,15 @@ def ipv4address(value):
     return address
 
 
+def ipv4address_multi_broadcast(value):
+    address = ipv4address(value)
+    if not (address.is_multicast or (address == IPv4Address("255.255.255.255"))):
+        raise Invalid(
+            f"{value} is not a multicasst address nor local broadcast address"
+        )
+    return address
+
+
 def ipaddress(value):
     try:
         address = ip_address(value)

tests/components/udp/common.yaml

@@ -7,6 +7,7 @@ udp:
   encryption: "our key goes here"
   rolling_code_enable: true
   ping_pong_enable: true
+  listen_address: 239.0.60.53
   binary_sensors:
     - binary_sensor_id1
     - id: binary_sensor_id1