--- /dev/null
+/* UDP MultiCast Send/Receive Example
+
+ This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+ Unless required by applicable law or agreed to in writing, this
+ software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+ CONDITIONS OF ANY KIND, either express or implied.
+*/
+#include <string.h>
+#include <sys/param.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "freertos/event_groups.h"
+#include "esp_system.h"
+#include "esp_wifi.h"
+#include "esp_event_loop.h"
+#include "esp_log.h"
+#include "nvs_flash.h"
+
+#include "lwip/err.h"
+#include "lwip/sockets.h"
+#include "lwip/sys.h"
+#include <lwip/netdb.h>
+
+/* The examples use simple WiFi configuration that you can set via
+ 'make menuconfig'.
+
+ If you'd rather not, just change the below entries to strings with
+ the config you want - ie #define EXAMPLE_WIFI_SSID "mywifissid"
+*/
+#define EXAMPLE_WIFI_SSID CONFIG_WIFI_SSID
+#define EXAMPLE_WIFI_PASS CONFIG_WIFI_PASSWORD
+
+#define UDP_PORT CONFIG_EXAMPLE_PORT
+
+#define MULTICAST_LOOPBACK CONFIG_EXAMPLE_LOOPBACK
+
+#define MULTICAST_TTL CONFIG_EXAMPLE_MULTICAST_TTL
+
+#define MULTICAST_IPV4_ADDR CONFIG_EXAMPLE_MULTICAST_IPV4_ADDR
+#define MULTICAST_IPV6_ADDR CONFIG_EXAMPLE_MULTICAST_IPV6_ADDR
+
+#define LISTEN_DEFAULT_IF CONFIG_EXAMPLE_LISTEN_DEFAULT_IF
+
+/* FreeRTOS event group to signal when we are connected & ready to make a request */
+static EventGroupHandle_t wifi_event_group;
+
+/* The event group allows multiple bits for each event,
+ we use two - one for IPv4 "got ip", and
+ one for IPv6 "got ip". */
+const int IPV4_GOTIP_BIT = BIT0;
+const int IPV6_GOTIP_BIT = BIT1;
+
+static const char *TAG = "multicast";
+#ifdef CONFIG_EXAMPLE_IPV4
+static const char *V4TAG = "mcast-ipv4";
+#endif
+#ifdef CONFIG_EXAMPLE_IPV6
+static const char *V6TAG = "mcast-ipv6";
+#endif
+
+static esp_err_t event_handler(void *ctx, system_event_t *event)
+{
+ switch(event->event_id) {
+ case SYSTEM_EVENT_STA_START:
+ esp_wifi_connect();
+ break;
+ case SYSTEM_EVENT_STA_CONNECTED:
+ /* enable ipv6 */
+ tcpip_adapter_create_ip6_linklocal(TCPIP_ADAPTER_IF_STA);
+ break;
+ case SYSTEM_EVENT_STA_GOT_IP:
+ xEventGroupSetBits(wifi_event_group, IPV4_GOTIP_BIT);
+ break;
+ case SYSTEM_EVENT_STA_DISCONNECTED:
+ /* This is a workaround as ESP32 WiFi libs don't currently
+ auto-reassociate. */
+ esp_wifi_connect();
+ xEventGroupClearBits(wifi_event_group, IPV4_GOTIP_BIT);
+ xEventGroupClearBits(wifi_event_group, IPV6_GOTIP_BIT);
+ break;
+ case SYSTEM_EVENT_AP_STA_GOT_IP6:
+ xEventGroupSetBits(wifi_event_group, IPV6_GOTIP_BIT);
+ default:
+ break;
+ }
+ return ESP_OK;
+}
+
+static void initialise_wifi(void)
+{
+ tcpip_adapter_init();
+ wifi_event_group = xEventGroupCreate();
+ ESP_ERROR_CHECK( esp_event_loop_init(event_handler, NULL) );
+ wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
+ ESP_ERROR_CHECK( esp_wifi_init(&cfg) );
+ ESP_ERROR_CHECK( esp_wifi_set_storage(WIFI_STORAGE_RAM) );
+ wifi_config_t wifi_config = {
+ .sta = {
+ .ssid = EXAMPLE_WIFI_SSID,
+ .password = EXAMPLE_WIFI_PASS,
+ },
+ };
+ ESP_LOGI(TAG, "Setting WiFi configuration SSID %s...", wifi_config.sta.ssid);
+ ESP_ERROR_CHECK( esp_wifi_set_mode(WIFI_MODE_STA) );
+ ESP_ERROR_CHECK( esp_wifi_set_config(ESP_IF_WIFI_STA, &wifi_config) );
+ ESP_ERROR_CHECK( esp_wifi_start() );
+}
+
+#ifdef CONFIG_EXAMPLE_IPV4
+/* Add a socket, either IPV4-only or IPV6 dual mode, to the IPV4
+ multicast group */
+static int socket_add_ipv4_multicast_group(int sock, bool assign_source_if)
+{
+ struct ip_mreq imreq = { 0 };
+ struct in_addr iaddr = { 0 };
+ int err = 0;
+ // Configure source interface
+#if USE_DEFAULT_IF
+ imreq.imr_interface.s_addr = IPADDR_ANY;
+#else
+ tcpip_adapter_ip_info_t ip_info = { 0 };
+ err = tcpip_adapter_get_ip_info(TCPIP_ADAPTER_IF_STA, &ip_info);
+ if (err != ESP_OK) {
+ ESP_LOGE(V4TAG, "Failed to get IP address info. Error 0x%x", err);
+ goto err;
+ }
+ inet_addr_from_ipaddr(&iaddr, &ip_info.ip);
+#endif
+ // Configure multicast address to listen to
+ err = inet_aton(MULTICAST_IPV4_ADDR, &imreq.imr_multiaddr.s_addr);
+ if (err != 1) {
+ ESP_LOGE(V4TAG, "Configured IPV4 multicast address '%s' is invalid.", MULTICAST_IPV4_ADDR);
+ goto err;
+ }
+ ESP_LOGI(TAG, "Configured IPV4 Multicast address %s", inet_ntoa(imreq.imr_multiaddr.s_addr));
+ if (!IP_MULTICAST(ntohl(imreq.imr_multiaddr.s_addr))) {
+ ESP_LOGW(V4TAG, "Configured IPV4 multicast address '%s' is not a valid multicast address. This will probably not work.", MULTICAST_IPV4_ADDR);
+ }
+
+ if (assign_source_if) {
+ // Assign the IPv4 multicast source interface, via its IP
+ // (only necessary if this socket is IPV4 only)
+ err = setsockopt(sock, IPPROTO_IP, IP_MULTICAST_IF, &iaddr,
+ sizeof(struct in_addr));
+ if (err < 0) {
+ ESP_LOGE(V4TAG, "Failed to set IP_MULTICAST_IF. Error %d", errno);
+ goto err;
+ }
+ }
+
+ err = setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
+ &imreq, sizeof(struct ip_mreq));
+ if (err < 0) {
+ ESP_LOGE(V4TAG, "Failed to set IP_ADD_MEMBERSHIP. Error %d", errno);
+ goto err;
+ }
+
+ err:
+ return err;
+}
+#endif /* CONFIG_EXAMPLE_IPV4 */
+
+#ifdef CONFIG_EXAMPLE_IPV4_ONLY
+static int create_multicast_ipv4_socket()
+{
+ struct sockaddr_in saddr = { 0 };
+ int sock = -1;
+ int err = 0;
+
+ sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
+ if (sock < 0) {
+ ESP_LOGE(V4TAG, "Failed to create socket. Error %d", errno);
+ return -1;
+ }
+
+ // Bind the socket to any address
+ saddr.sin_family = PF_INET;
+ saddr.sin_port = htons(UDP_PORT);
+ saddr.sin_addr.s_addr = htonl(INADDR_ANY);
+ err = bind(sock, (struct sockaddr *)&saddr, sizeof(struct sockaddr_in));
+ if (err < 0) {
+ ESP_LOGE(V4TAG, "Failed to bind socket. Error %d", errno);
+ goto err;
+ }
+
+
+ // Assign multicast TTL (set separately from normal interface TTL)
+ uint8_t ttl = MULTICAST_TTL;
+ setsockopt(sock, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(uint8_t));
+ if (err < 0) {
+ ESP_LOGE(V4TAG, "Failed to set IP_MULTICAST_TTL. Error %d", errno);
+ goto err;
+ }
+
+#if MULTICAST_LOOPBACK
+ // select whether multicast traffic should be received by this device, too
+ // (if setsockopt() is not called, the default is no)
+ uint8_t loopback_val = MULTICAST_LOOPBACK;
+ err = setsockopt(sock, IPPROTO_IP, IP_MULTICAST_LOOP,
+ &loopback_val, sizeof(uint8_t));
+ if (err < 0) {
+ ESP_LOGE(V4TAG, "Failed to set IP_MULTICAST_LOOP. Error %d", errno);
+ goto err;
+ }
+#endif
+
+ // this is also a listening socket, so add it to the multicast
+ // group for listening...
+ err = socket_add_ipv4_multicast_group(sock, true);
+ if (err < 0) {
+ goto err;
+ }
+
+ // All set, socket is configured for sending and receiving
+ return sock;
+
+err:
+ close(sock);
+ return -1;
+}
+#endif /* CONFIG_EXAMPLE_IPV4_ONLY */
+
+#ifdef CONFIG_EXAMPLE_IPV6
+static int create_multicast_ipv6_socket()
+{
+ struct sockaddr_in6 saddr = { 0 };
+ struct in6_addr if_inaddr = { 0 };
+ struct ip6_addr if_ipaddr = { 0 };
+ struct ip6_mreq v6imreq = { 0 };
+ int sock = -1;
+ int err = 0;
+
+ sock = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IPV6);
+ if (sock < 0) {
+ ESP_LOGE(V6TAG, "Failed to create socket. Error %d", errno);
+ return -1;
+ }
+
+ // Bind the socket to any address
+ saddr.sin6_family = AF_INET6;
+ saddr.sin6_port = htons(UDP_PORT);
+ bzero(&saddr.sin6_addr.un, sizeof(saddr.sin6_addr.un));
+ err = bind(sock, (struct sockaddr *)&saddr, sizeof(struct sockaddr_in6));
+ if (err < 0) {
+ ESP_LOGE(V6TAG, "Failed to bind socket. Error %d", errno);
+ goto err;
+ }
+
+ // Selct the interface to use as multicast source for this socket.
+#if USE_DEFAULT_IF
+ bzero(&if_inaddr.un, sizeof(if_inaddr.un));
+#else
+ // Read interface adapter link-local address and use it
+ // to bind the multicast IF to this socket.
+ //
+ // (Note the interface may have other non-LL IPV6 addresses as well,
+ // but it doesn't matter in this context as the address is only
+ // used to identify the interface.)
+ err = tcpip_adapter_get_ip6_linklocal(TCPIP_ADAPTER_IF_STA, &if_ipaddr);
+ inet6_addr_from_ip6addr(&if_inaddr, &if_ipaddr);
+ if (err != ESP_OK) {
+ ESP_LOGE(V6TAG, "Failed to get IPV6 LL address. Error 0x%x", err);
+ goto err;
+ }
+#endif
+
+ // Assign the multicast source interface, via its IP
+ err = setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_IF, &if_inaddr,
+ sizeof(struct in6_addr));
+ if (err < 0) {
+ ESP_LOGE(V6TAG, "Failed to set IPV6_MULTICAST_IF. Error %d", errno);
+ goto err;
+ }
+
+ // Assign multicast TTL (set separately from normal interface TTL)
+ uint8_t ttl = MULTICAST_TTL;
+ setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(uint8_t));
+ if (err < 0) {
+ ESP_LOGE(V6TAG, "Failed to set IPV6_MULTICAST_HOPS. Error %d", errno);
+ goto err;
+ }
+
+#if MULTICAST_LOOPBACK
+ // select whether multicast traffic should be received by this device, too
+ // (if setsockopt() is not called, the default is no)
+ uint8_t loopback_val = MULTICAST_LOOPBACK;
+ err = setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP,
+ &loopback_val, sizeof(uint8_t));
+ if (err < 0) {
+ ESP_LOGE(V6TAG, "Failed to set IPV6_MULTICAST_LOOP. Error %d", errno);
+ goto err;
+ }
+#endif
+
+ // this is also a listening socket, so add it to the multicast
+ // group for listening...
+
+ // Configure source interface
+#if USE_DEFAULT_IF
+ v6imreq.imr_interface.s_addr = IPADDR_ANY;
+#else
+ inet6_addr_from_ip6addr(&v6imreq.ipv6mr_interface, &if_ipaddr);
+#endif
+#ifdef CONFIG_EXAMPLE_IPV6
+ // Configure multicast address to listen to
+ err = inet6_aton(MULTICAST_IPV6_ADDR, &v6imreq.ipv6mr_multiaddr);
+ if (err != 1) {
+ ESP_LOGE(V6TAG, "Configured IPV6 multicast address '%s' is invalid.", MULTICAST_IPV6_ADDR);
+ goto err;
+ }
+ ESP_LOGI(TAG, "Configured IPV6 Multicast address %s", inet6_ntoa(v6imreq.ipv6mr_multiaddr));
+ ip6_addr_t multi_addr;
+ inet6_addr_to_ip6addr(&multi_addr, &v6imreq.ipv6mr_multiaddr);
+ if (!ip6_addr_ismulticast(&multi_addr)) {
+ ESP_LOGW(V6TAG, "Configured IPV6 multicast address '%s' is not a valid multicast address. This will probably not work.", MULTICAST_IPV6_ADDR);
+ }
+
+ err = setsockopt(sock, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP,
+ &v6imreq, sizeof(struct ip6_mreq));
+ if (err < 0) {
+ ESP_LOGE(V6TAG, "Failed to set IPV6_ADD_MEMBERSHIP. Error %d", errno);
+ goto err;
+ }
+#endif
+
+#if CONFIG_EXAMPLE_IPV4_V6
+ // Add the common IPV4 config options
+ err = socket_add_ipv4_multicast_group(sock, false);
+ if (err < 0) {
+ goto err;
+ }
+#endif
+
+#if CONFIG_EXAMPLE_IPV4_V6
+ int only = 0;
+#else
+ int only = 1; /* IPV6-only socket */
+#endif
+ err = setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &only, sizeof(int));
+ if (err < 0) {
+ ESP_LOGE(V6TAG, "Failed to set IPV6_V6ONLY. Error %d", errno);
+ goto err;
+ }
+ ESP_LOGI(TAG, "Socket set IPV6-only");
+
+ // All set, socket is configured for sending and receiving
+ return sock;
+
+err:
+ close(sock);
+ return -1;
+}
+#endif
+
+static void mcast_example_task(void *pvParameters)
+{
+ while (1) {
+ /* Wait for all the IPs we care about to be set
+ */
+ uint32_t bits = 0;
+#ifdef CONFIG_EXAMPLE_IPV4
+ bits |= IPV4_GOTIP_BIT;
+#endif
+#ifdef CONFIG_EXAMPLE_IPV6
+ bits |= IPV6_GOTIP_BIT;
+#endif
+ ESP_LOGI(TAG, "Waiting for AP connection...");
+ xEventGroupWaitBits(wifi_event_group, bits, false, true, portMAX_DELAY);
+ ESP_LOGI(TAG, "Connected to AP");
+
+ int sock;
+
+#ifdef CONFIG_EXAMPLE_IPV4_ONLY
+ sock = create_multicast_ipv4_socket();
+ if (sock < 0) {
+ ESP_LOGE(TAG, "Failed to create IPv4 multicast socket");
+ }
+#else
+ sock = create_multicast_ipv6_socket();
+ if (sock < 0) {
+ ESP_LOGE(TAG, "Failed to create IPv6 multicast socket");
+ }
+#endif
+
+ if (sock < 0) {
+ // Nothing to do!
+ vTaskDelay(5 / portTICK_PERIOD_MS);
+ continue;
+ }
+
+#ifdef CONFIG_EXAMPLE_IPV4
+ // set destination multicast addresses for sending from these sockets
+ struct sockaddr_in sdestv4 = {
+ .sin_family = PF_INET,
+ .sin_port = htons(UDP_PORT),
+ };
+ // We know this inet_aton will pass because we did it above already
+ inet_aton(MULTICAST_IPV4_ADDR, &sdestv4.sin_addr.s_addr);
+#endif
+
+#ifdef CONFIG_EXAMPLE_IPV6
+ struct sockaddr_in6 sdestv6 = {
+ .sin6_family = PF_INET6,
+ .sin6_port = htons(UDP_PORT),
+ };
+ // We know this inet_aton will pass because we did it above already
+ inet6_aton(MULTICAST_IPV6_ADDR, &sdestv6.sin6_addr);
+#endif
+
+ // Loop waiting for UDP received, and sending UDP packets if we don't
+ // see any.
+ int err = 1;
+ while (err > 0) {
+ struct timeval tv = {
+ .tv_sec = 2,
+ .tv_usec = 0,
+ };
+ fd_set rfds;
+ FD_ZERO(&rfds);
+ FD_SET(sock, &rfds);
+
+ int s = lwip_select(sock + 1, &rfds, NULL, NULL, &tv);
+ if (s < 0) {
+ ESP_LOGE(TAG, "Select failed: errno %d", errno);
+ err = -1;
+ break;
+ }
+ else if (s > 0) {
+ if (FD_ISSET(sock, &rfds)) {
+ // Incoming datagram received
+ char recvbuf[48];
+ char raddr_name[32] = { 0 };
+
+ struct sockaddr_in6 raddr; // Large enough for both IPv4 or IPv6
+ socklen_t socklen = sizeof(raddr);
+ int len = recvfrom(sock, recvbuf, sizeof(recvbuf)-1, 0,
+ (struct sockaddr *)&raddr, &socklen);
+ if (len < 0) {
+ ESP_LOGE(TAG, "multicast recvfrom failed: errno %d", errno);
+ err = -1;
+ break;
+ }
+
+ // Get the sender's address as a string
+#ifdef CONFIG_EXAMPLE_IPV4
+ if (raddr.sin6_family == PF_INET) {
+ inet_ntoa_r(((struct sockaddr_in *)&raddr)->sin_addr.s_addr,
+ raddr_name, sizeof(raddr_name)-1);
+ }
+#endif
+#ifdef CONFIG_EXAMPLE_IPV6
+ if (raddr.sin6_family == PF_INET6) {
+ inet6_ntoa_r(raddr.sin6_addr, raddr_name, sizeof(raddr_name)-1);
+ }
+#endif
+ ESP_LOGI(TAG, "received %d bytes from %s:", len, raddr_name);
+
+ recvbuf[len] = 0; // Null-terminate whatever we received and treat like a string...
+ ESP_LOGI(TAG, "%s", recvbuf);
+ }
+ }
+ else { // s == 0
+ // Timeout passed with no incoming data, so send something!
+ static int send_count;
+ const char sendfmt[] = "Multicast #%d sent by ESP32\n";
+ char sendbuf[48];
+ char addrbuf[32] = { 0 };
+ int len = snprintf(sendbuf, sizeof(sendbuf), sendfmt, send_count++);
+ if (len > sizeof(sendbuf)) {
+ ESP_LOGE(TAG, "Overflowed multicast sendfmt buffer!!");
+ send_count = 0;
+ err = -1;
+ break;
+ }
+
+ struct addrinfo hints = {
+ .ai_flags = AI_PASSIVE,
+ .ai_socktype = SOCK_DGRAM,
+ };
+ struct addrinfo *res;
+
+#ifdef CONFIG_EXAMPLE_IPV4 // Send an IPv4 multicast packet
+
+#ifdef CONFIG_EXAMPLE_IPV4_ONLY
+ hints.ai_family = AF_INET; // For an IPv4 socket
+#else
+ hints.ai_family = AF_INET6; // For an IPv4 socket with V4 mapped addresses
+ hints.ai_flags |= AI_V4MAPPED;
+#endif
+ int err = getaddrinfo(CONFIG_EXAMPLE_MULTICAST_IPV4_ADDR,
+ NULL,
+ &hints,
+ &res);
+ if (err < 0) {
+ ESP_LOGE(TAG, "getaddrinfo() failed for IPV4 destination address. error: %d", err);
+ break;
+ }
+#ifdef CONFIG_EXAMPLE_IPV4_ONLY
+ ((struct sockaddr_in *)res->ai_addr)->sin_port = htons(UDP_PORT);
+ inet_ntoa_r(((struct sockaddr_in *)res->ai_addr)->sin_addr, addrbuf, sizeof(addrbuf)-1);
+ ESP_LOGI(TAG, "Sending to IPV4 multicast address %s...", addrbuf);
+#else
+ ((struct sockaddr_in6 *)res->ai_addr)->sin6_port = htons(UDP_PORT);
+ inet6_ntoa_r(((struct sockaddr_in6 *)res->ai_addr)->sin6_addr, addrbuf, sizeof(addrbuf)-1);
+ ESP_LOGI(TAG, "Sending to IPV6 (V4 mapped) multicast address %s (%s)...", addrbuf, CONFIG_EXAMPLE_MULTICAST_IPV4_ADDR);
+#endif
+ err = sendto(sock, sendbuf, len, 0, res->ai_addr, res->ai_addrlen);
+ if (err < 0) {
+ ESP_LOGE(TAG, "IPV4 sendto failed. errno: %d", errno);
+ break;
+ }
+#endif
+#ifdef CONFIG_EXAMPLE_IPV6
+ hints.ai_family = AF_INET6;
+ hints.ai_protocol = 0;
+ err = getaddrinfo(CONFIG_EXAMPLE_MULTICAST_IPV6_ADDR,
+ NULL,
+ &hints,
+ &res);
+ if (err < 0) {
+ ESP_LOGE(TAG, "getaddrinfo() failed for IPV6 destination address. error: %d", err);
+ break;
+ }
+
+
+ struct sockaddr_in6 *s6addr = (struct sockaddr_in6 *)res->ai_addr;
+ s6addr->sin6_port = htons(UDP_PORT);
+ inet6_ntoa_r(s6addr->sin6_addr, addrbuf, sizeof(addrbuf)-1);
+ ESP_LOGI(TAG, "Sending to IPV6 multicast address %s...", addrbuf);
+ err = sendto(sock, sendbuf, len, 0, res->ai_addr, res->ai_addrlen);
+ if (err < 0) {
+ ESP_LOGE(TAG, "IPV6 sendto failed. errno: %d", errno);
+ break;
+ }
+#endif
+ }
+ }
+
+ ESP_LOGE(TAG, "Shutting down socket and restarting...");
+ shutdown(sock, 0);
+ close(sock);
+ }
+
+}
+
+void app_main()
+{
+ ESP_ERROR_CHECK( nvs_flash_init() );
+ initialise_wifi();
+ xTaskCreate(&mcast_example_task, "mcast_task", 4096, NULL, 5, NULL);
+}
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