mdns: Fixed the ip header TTL to be correctly set to 255

david-cermak · suren-gabrielyan-espressif · commit ab3fa69b8fb8 · 2022-05-27T17:44:24.000+04:00
Defined in https://tools.ietf.org/html/rfc6762#section-11: All Multicast DNS responses (including responses sent via unicast) SHOULD be sent with IP TTL set to 255 * Original commit: espressif/esp-idf@5cce919
diff --git a/components/mdns/mdns_networking.c b/components/mdns/mdns_networking.c
@@ -38,7 +38,7 @@ static esp_err_t _udp_pcb_main_init(void)
         _pcb_main = NULL;
         return ESP_ERR_INVALID_STATE;
     }
-    _pcb_main->mcast_ttl = 1;
+    _pcb_main->mcast_ttl = 255;
     _pcb_main->remote_port = MDNS_SERVICE_PORT;
     ip_addr_copy(_pcb_main->remote_ip, *(IP_ANY_TYPE));
     udp_recv(_pcb_main, &_udp_recv, _mdns_server);

Original file line number	Diff line number	Diff line change
`@@ -38,7 +38,7 @@ static esp_err_t _udp_pcb_main_init(void)`
`38`	`38`	`_pcb_main = NULL;`
`39`	`39`	`return ESP_ERR_INVALID_STATE;`
`40`	`40`	`}`
`41`		`- _pcb_main->mcast_ttl = 1;`
	`41`	`+ _pcb_main->mcast_ttl = 255;`
`42`	`42`	`_pcb_main->remote_port = MDNS_SERVICE_PORT;`
`43`	`43`	`ip_addr_copy(_pcb_main->remote_ip, *(IP_ANY_TYPE));`
`44`	`44`	`udp_recv(_pcb_main, &_udp_recv, _mdns_server);`