Register to multicast groups (ARMmbed#66)

* Register to multicast groups

COAP service registers automatically to COAP multicast groups:
-ff02::fd (link-local according to RFC 7390)
-ff05::fd (site local according to RFC 7390)

coap-service/coap_service_api.h

@@ -58,6 +58,10 @@ extern "C" {
 #define COAP_REQUEST_OPTIONS_MULTICAST 0x04 //!< indicates that CoAP library support multicasting
 #define COAP_REQUEST_OPTIONS_SECURE_BYPASS 0x08
 
+extern const uint8_t COAP_MULTICAST_ADDR_LINK_LOCAL[16]; //!< ff02::fd, COAP link local multicast address
+extern const uint8_t COAP_MULTICAST_ADDR_ADMIN_LOCAL[16]; //!< ff03::fd, COAP admin-local multicast address
+extern const uint8_t COAP_MULTICAST_ADDR_SITE_LOCAL[16]; //!> ff05::fd, COAP site-local multicast address
+
 /**
  * \brief Service message response receive callback.
  *

source/coap_connection_handler.c

@@ -42,6 +42,10 @@ typedef struct internal_socket_s {
  ns_list_link_t link;
 } internal_socket_t;
 
+const uint8_t COAP_MULTICAST_ADDR_LINK_LOCAL[16] = { 0xff, 0x02, [15] = 0xfd }; // ff02::fd, COAP link-local multicast (rfc7390)
+const uint8_t COAP_MULTICAST_ADDR_ADMIN_LOCAL[16] = { 0xff, 0x03, [15] = 0xfd }; // ff02::fd, COAP admin-local multicast (rfc7390)
+const uint8_t COAP_MULTICAST_ADDR_SITE_LOCAL[16] = { 0xff, 0x05, [15] = 0xfd }; // ff05::fd, COAP site-local multicast (rfc7390)
+
 static NS_LIST_DEFINE(socket_list, internal_socket_t, link);
 
 static void timer_cb(void* param);
@@ -223,7 +227,9 @@ static secure_session_t *secure_session_find(internal_socket_t *parent, const ui
 
 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)
 {
+ ns_ipv6_mreq_t ns_ipv6_mreq;
  internal_socket_t *this = ns_dyn_mem_alloc(sizeof(internal_socket_t));
+
  if (!this) {
  return NULL;
  }
@@ -265,10 +271,22 @@ static internal_socket_t *int_socket_create(uint16_t listen_port, bool use_ephem
 
  // Set socket option to receive packet info
  socket_setsockopt(this->socket, SOCKET_IPPROTO_IPV6, SOCKET_IPV6_RECVPKTINFO, &(const bool) {1}, sizeof(bool));
- if (socket_interface_selection != -1) {
- // Select socket interface if selection requested
- socket_setsockopt(this->socket, SOCKET_IPPROTO_IPV6, SOCKET_INTERFACE_SELECT, &socket_interface_selection, sizeof(int8_t));
+ if (socket_interface_selection > 0) {
+ // Interface selection requested as socket_interface_selection set
+ 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));
  } else {
  this->socket = virtual_socket_id_allocate();
  }

source/coap_service_api.c

@@ -280,7 +280,7 @@ 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 = -1;
+ 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;