Add option to join COAP multicast group (ARMmbed#67)

* Add option to join COAP multicast group

Option COAP_SERVICE_OPTIONS_MULTICAST_JOIN added to service_api to
join COAP multicast group. The group is left when service is deleted.

Author: Arto Kinnunen

coap-service/coap_service_api.h

@@ -47,6 +47,8 @@ extern "C" {
 #define COAP_SERVICE_OPTIONS_EPHEMERAL_PORT     0x04
 /** Coap interface selected as socket interface */
 #define COAP_SERVICE_OPTIONS_SELECT_SOCKET_IF   0x08
+/** Register to COAP multicast groups */
+#define COAP_SERVICE_OPTIONS_MULTICAST_JOIN     0x10
 /** Link-layer security bypass option is set*/
 #define COAP_SERVICE_OPTIONS_SECURE_BYPASS      0x80
 

source/coap_connection_handler.c

@@ -225,9 +225,30 @@ static secure_session_t *secure_session_find(internal_socket_t *parent, const ui
     return this;
 }
 
-static internal_socket_t *int_socket_create(uint16_t listen_port, bool use_ephemeral_port, bool is_secure, bool real_socket, bool bypassSec, int8_t socket_interface_selection)
+static void coap_multicast_group_join_or_leave(int8_t socket_id, uint8_t opt_name, int8_t interface_id)
 {
     ns_ipv6_mreq_t ns_ipv6_mreq;
+    int8_t ret_val;
+
+    // Join or leave COAP multicast groups
+    ns_ipv6_mreq.ipv6mr_interface = interface_id;
+
+    memcpy(ns_ipv6_mreq.ipv6mr_multiaddr, COAP_MULTICAST_ADDR_LINK_LOCAL, 16);
+    ret_val = socket_setsockopt(socket_id, SOCKET_IPPROTO_IPV6, opt_name, &ns_ipv6_mreq, sizeof(ns_ipv6_mreq));
+
+    memcpy(ns_ipv6_mreq.ipv6mr_multiaddr, COAP_MULTICAST_ADDR_ADMIN_LOCAL, 16);
+    ret_val |= socket_setsockopt(socket_id, SOCKET_IPPROTO_IPV6, opt_name, &ns_ipv6_mreq, sizeof(ns_ipv6_mreq));
+
+    memcpy(ns_ipv6_mreq.ipv6mr_multiaddr, COAP_MULTICAST_ADDR_SITE_LOCAL, 16);
+    ret_val |= socket_setsockopt(socket_id, SOCKET_IPPROTO_IPV6, opt_name, &ns_ipv6_mreq, sizeof(ns_ipv6_mreq));
+
+    if (ret_val) {
+        tr_error("Multicast group access failed, err=%d, name=%d", ret_val, opt_name);
+    }
+}
+
+static internal_socket_t *int_socket_create(uint16_t listen_port, bool use_ephemeral_port, bool is_secure, bool real_socket, bool bypassSec, int8_t socket_interface_selection, bool multicast_registration)
+{
     internal_socket_t *this = ns_dyn_mem_alloc(sizeof(internal_socket_t));
 
     if (!this) {
@@ -276,17 +297,9 @@ static internal_socket_t *int_socket_create(uint16_t listen_port, bool use_ephem
             socket_setsockopt(this->socket, SOCKET_IPPROTO_IPV6, SOCKET_INTERFACE_SELECT, &socket_interface_selection, sizeof(socket_interface_selection));
         }
 
-        // Join COAP multicast group(s)
-        ns_ipv6_mreq.ipv6mr_interface = socket_interface_selection; // It is OK to use 0 or real interface id here
-
-        memcpy(ns_ipv6_mreq.ipv6mr_multiaddr, COAP_MULTICAST_ADDR_LINK_LOCAL, 16);
-        socket_setsockopt(this->socket, SOCKET_IPPROTO_IPV6, SOCKET_IPV6_JOIN_GROUP, &ns_ipv6_mreq, sizeof(ns_ipv6_mreq));
-
-        memcpy(ns_ipv6_mreq.ipv6mr_multiaddr, COAP_MULTICAST_ADDR_ADMIN_LOCAL, 16);
-        socket_setsockopt(this->socket, SOCKET_IPPROTO_IPV6, SOCKET_IPV6_JOIN_GROUP, &ns_ipv6_mreq, sizeof(ns_ipv6_mreq));
-
-        memcpy(ns_ipv6_mreq.ipv6mr_multiaddr, COAP_MULTICAST_ADDR_SITE_LOCAL, 16);
-        socket_setsockopt(this->socket, SOCKET_IPPROTO_IPV6, SOCKET_IPV6_JOIN_GROUP, &ns_ipv6_mreq, sizeof(ns_ipv6_mreq));
+        if (multicast_registration) {
+            coap_multicast_group_join_or_leave(this->socket, SOCKET_IPV6_JOIN_GROUP, socket_interface_selection);
+        }
     } else {
         this->socket = virtual_socket_id_allocate();
     }
@@ -793,9 +806,13 @@ coap_conn_handler_t *connection_handler_create(receive_from_socket_cb *recv_from
 
     return handler;
 }
-void connection_handler_destroy(coap_conn_handler_t *handler)
+
+void connection_handler_destroy(coap_conn_handler_t *handler, bool multicast_group_leave)
 {
     if(handler){
+        if (multicast_group_leave) {
+            coap_multicast_group_join_or_leave(handler->socket->socket, SOCKET_IPV6_LEAVE_GROUP, handler->socket_interface_selection);
+        }
        int_socket_delete(handler->socket);
        ns_dyn_mem_free(handler);
     }
@@ -815,7 +832,7 @@ void connection_handler_close_secure_connection( coap_conn_handler_t *handler, u
     }
 }
 
-int coap_connection_handler_open_connection(coap_conn_handler_t *handler, uint16_t listen_port, bool use_ephemeral_port, bool is_secure, bool is_real_socket, bool bypassSec, int8_t socket_interface_selection)
+int coap_connection_handler_open_connection(coap_conn_handler_t *handler, uint16_t listen_port, bool use_ephemeral_port, bool is_secure, bool is_real_socket, bool bypassSec)
 {
     if (!handler) {
         return -1;
@@ -830,7 +847,7 @@ int coap_connection_handler_open_connection(coap_conn_handler_t *handler, uint16
 
     internal_socket_t *current = !use_ephemeral_port?int_socket_find(listen_port, is_secure, is_real_socket, bypassSec):NULL;
     if (!current) {
-        handler->socket = int_socket_create(listen_port, use_ephemeral_port, is_secure, is_real_socket, bypassSec, socket_interface_selection);
+        handler->socket = int_socket_create(listen_port, use_ephemeral_port, is_secure, is_real_socket, bypassSec, handler->socket_interface_selection, handler->registered_to_multicast);
         if (!handler->socket) {
             return -1;
         }

source/coap_service_api.c

@@ -99,6 +99,27 @@ static coap_service_t *service_find_by_uri(uint8_t socket_id, uint8_t *uri_ptr,
     return NULL;
 }
 
+static bool coap_service_can_leave_multicast_group(coap_conn_handler_t *conn_handler)
+{
+    int mc_count = 0;
+    bool current_handler_joined_to_mc_group = false;
+
+    ns_list_foreach(coap_service_t, cur_ptr, &instance_list) {
+        if (cur_ptr->conn_handler && cur_ptr->conn_handler->registered_to_multicast) {
+            if (conn_handler == cur_ptr->conn_handler) {
+                current_handler_joined_to_mc_group = true;
+            }
+            mc_count ++;
+        }
+    }
+
+    if (mc_count == 1 && current_handler_joined_to_mc_group) {
+        // current handler is the only one joined to multicast group
+        return true;
+    }
+
+    return false;
+}
 
 /**
  *  Coap handling functions
@@ -280,8 +301,8 @@ static int get_passwd_cb(int8_t socket_id, uint8_t address[static 16], uint16_t
 int8_t coap_service_initialize(int8_t interface_id, uint16_t listen_port, uint8_t service_options,
                                  coap_service_security_start_cb *start_ptr, coap_service_security_done_cb *coap_security_done_cb)
 {
-    int8_t socket_interface_selection = 0; // zero is illegal interface ID
     coap_service_t *this = ns_dyn_mem_alloc(sizeof(coap_service_t));
+
     if (!this) {
         return -1;
     }
@@ -310,16 +331,18 @@ int8_t coap_service_initialize(int8_t interface_id, uint16_t listen_port, uint8_
         return -1;
     }
 
+    this->conn_handler->socket_interface_selection = 0; // zero is illegal interface ID
     if (this->service_options & COAP_SERVICE_OPTIONS_SELECT_SOCKET_IF) {
-        socket_interface_selection = this->interface_id;
+        this->conn_handler->socket_interface_selection = this->interface_id;
     }
 
+    this->conn_handler->registered_to_multicast = this->service_options & COAP_SERVICE_OPTIONS_MULTICAST_JOIN;
+
     if (0 > coap_connection_handler_open_connection(this->conn_handler, listen_port,
             (this->service_options & COAP_SERVICE_OPTIONS_EPHEMERAL_PORT),
             (this->service_options & COAP_SERVICE_OPTIONS_SECURE),
             !(this->service_options & COAP_SERVICE_OPTIONS_VIRTUAL_SOCKET),
-            (this->service_options & COAP_SERVICE_OPTIONS_SECURE_BYPASS),
-             socket_interface_selection)) {
+            (this->service_options & COAP_SERVICE_OPTIONS_SECURE_BYPASS))) {
         ns_dyn_mem_free(this->conn_handler);
         ns_dyn_mem_free(this);
         return -1;
@@ -346,7 +369,12 @@ void coap_service_delete(int8_t service_id)
     }
 
     if (this->conn_handler){
-        connection_handler_destroy(this->conn_handler);
+        bool leave_multicast_group = false;
+        if (coap_service_can_leave_multicast_group(this->conn_handler)) {
+            // This is the last handler joined to multicast group
+            leave_multicast_group = true;
+        }
+        connection_handler_destroy(this->conn_handler, leave_multicast_group);
     }
 
     //TODO clear all transactions

source/include/coap_connection_handler.h

@@ -44,18 +44,20 @@ typedef struct coap_conn_handler_s{
     send_to_socket_cb *_send_cb;
     get_pw_cb *_get_password_cb;
     security_done_cb *_security_done_cb;
+    int8_t socket_interface_selection;
+    bool registered_to_multicast;
 } coap_conn_handler_t;
 
 coap_conn_handler_t *connection_handler_create(receive_from_socket_cb *recv_from_cb,
                                                  send_to_socket_cb *send_to_cb,
                                                  get_pw_cb *pw_cb,
                                                  security_done_cb *done_cb);
 
-void connection_handler_destroy( coap_conn_handler_t *handler );
+void connection_handler_destroy( coap_conn_handler_t *handler, bool multicast_group_leave);
 
 void connection_handler_close_secure_connection( coap_conn_handler_t *handler, uint8_t destination_addr_ptr[static 16], uint16_t port );
 
-int coap_connection_handler_open_connection(coap_conn_handler_t *handler, uint16_t listen_port, bool use_ephemeral_port, bool is_secure, bool real_socket, bool bypassSec, int8_t socket_interface_selection);
+int coap_connection_handler_open_connection(coap_conn_handler_t *handler, uint16_t listen_port, bool use_ephemeral_port, bool is_secure, bool real_socket, bool bypassSec);
 
 //If returns -2, it means security was started and data was not send
 int coap_connection_handler_send_data(coap_conn_handler_t *handler, const ns_address_t *dest_addr, const uint8_t src_address[static 16], uint8_t *data_ptr, uint16_t data_len, bool bypass_link_sec);