Add function to eliminate ICE redundant candidates.

include/mediastreamer2/ice.h

@@ -466,6 +466,16 @@ void ice_session_set_base_for_srflx_candidates(IceSession *session);
  */
 MS2_PUBLIC void ice_session_compute_candidates_foundations(IceSession *session);
 
+/**
+ * Eliminate the redundant candidates of an ICE session.
+ *
+ * @param session A pointer to a session
+ *
+ * This function is to be called at the end of the local candidates gathering process, before sending
+ * the SDP to the remote agent.
+ */
+MS2_PUBLIC void ice_session_eliminate_redundant_candidates(IceSession *session);
+
 /**
  * Choose the default candidates of an ICE session.
  *

src/ice.c

@@ -1469,6 +1469,52 @@ void ice_session_compute_candidates_foundations(IceSession *session)
 }
 
 
+/******************************************************************************
+ * ELIMINATE REDUNDANT CANDIDATES                                             *
+ *****************************************************************************/
+
+static int ice_find_redundant_candidate(const IceCandidate *c1, const IceCandidate *c2)
+{
+	if (c1 == c2) return 1;
+	return !(!ice_compare_transport_addresses(&c1->taddr, &c2->taddr) && (c1->base == c2->base));
+}
+
+static void ice_check_list_eliminate_redundant_candidates(IceCheckList *cl)
+{
+	MSList *elem;
+	MSList *other_elem;
+	IceCandidate *candidate;
+	IceCandidate *other_candidate;
+	bool_t elem_removed;
+
+	do {
+		elem_removed = FALSE;
+		/* Do not use ms_list_for_each2() here, we may remove list elements. */
+		for (elem = cl->local_candidates; elem != NULL; elem = elem->next) {
+			candidate = (IceCandidate *)elem->data;
+			other_elem = ms_list_find_custom(cl->local_candidates, (MSCompareFunc)ice_find_redundant_candidate, candidate);
+			if (other_elem != NULL) {
+				other_candidate = (IceCandidate *)other_elem->data;
+				if (other_candidate->priority < candidate->priority) {
+					ice_free_candidate(other_candidate);
+					cl->local_candidates = ms_list_remove_link(cl->local_candidates, other_elem);
+				} else {
+					ice_free_candidate(candidate);
+					cl->local_candidates = ms_list_remove_link(cl->local_candidates, elem);
+				}
+				elem_removed = TRUE;
+				break;
+			}
+		}
+	} while (elem_removed);
+}
+
+void ice_session_eliminate_redundant_candidates(IceSession *session)
+{
+	ms_list_for_each(session->streams, (void (*)(void*))ice_check_list_eliminate_redundant_candidates);
+}
+
+
 /******************************************************************************
  * CHOOSE DEFAULT CANDIDATES                                                  *
  *****************************************************************************/