TT#35413 add support for rtpengine load balancing

Change-Id: I0e212ecd99810162c058ed1dfc8055ce7ae3d792

debian/patches/series

@@ -31,3 +31,4 @@ sipwise/sca-fix-notify-after-bye.patch
 sipwise/fix_db_redis_time_schema.patch
 sipwise/fix_db_redis_free_memory.patch
 sipwise/fix_db_redis_memory_issues.patch
+sipwise/rtpengine-balancing.patch

debian/patches/sipwise/rtpengine-balancing.patch

@@ -0,0 +1,48 @@
+--- a/src/modules/rtpengine/rtpengine.c
++++ b/src/modules/rtpengine/rtpengine.c
+@@ -2109,6 +2109,7 @@
+ 	pv_value_t pv_val;
+ 	char md5[MD5_LEN];
+ 	char branch_buf[MAX_BRANCH_PARAM_LEN];
++	bencode_item_t *result;
+ 
+ 	/*** get & init basic stuff needed ***/
+ 
+@@ -2132,6 +2133,9 @@
+ 	}
+ 	ng_flags.dict = bencode_dictionary(bencbuf);
+ 
++	item = bencode_dictionary_add_list(ng_flags.dict, "supports");
++	bencode_list_add_string(item, "load limit");
++
+ 	body.s = NULL;
+ 	if (op == OP_OFFER || op == OP_ANSWER) {
+ 		ng_flags.flags = bencode_list(bencbuf);
+@@ -2282,7 +2286,26 @@
+ 		goto error;
+ 	}
+ 
+-	if (!bencode_dictionary_get_strcmp(resp, "result", "error")) {
++	result = bencode_dictionary_get_expect(resp, "result", BENCODE_STRING);
++	if (!result) {
++		LM_ERR("No 'result' dictionary entry in response from proxy %.*s",
++				node->rn_url.len, node->rn_url.s);
++		goto error;
++	}
++
++	if (!bencode_strcmp(result, "load limit")) {
++		item = bencode_dictionary_get_expect(resp, "message", BENCODE_STRING);
++		if (!item)
++			LM_INFO("proxy %.*s has reached its load limit - trying next one",
++					node->rn_url.len, node->rn_url.s);
++		else
++			LM_INFO("proxy %.*s has reached its load limit (%.*s) - trying next one",
++					node->rn_url.len, node->rn_url.s,
++					item->iov[1].iov_len, item->iov[1].iov_base);
++		goto select_node;
++	}
++
++	if (!bencode_strcmp(result, "error")) {
+ 		if (!bencode_dictionary_get_str(resp, "error-reason", &error)) {
+ 			LM_ERR("proxy return error but didn't give an error reason: %.*s\n", ret, cp);
+ 		} else {