rtp_engine: Prevent unnecessary memory increases during calls.

The doxygen for ast_rtp_codecs_payloads_copy() states:

"This copies the payloads from the codecs0 structure to the codecs1
structure, overwriting any current values."

However, in practice, the overwriting of current values was not
happening. Instead, a new RTP codec payload object would be appended to
the codecs1 structure instead of replacing the corresponding object.

This patch corrects this behavior by overwriting the object in the
codecs1 structure if it exists already. If it does not already exist,
then create a new copy and link it in.

Tests of "memory show summary rtp_engine.c" had previously shown
additional allocations being performed any time that Asterisk processed
an incoming SDP. Scenarios involving lots of reinvites resulted in lots
of allocations. With this patch, I can perform as many reinvites as
I want and see no memory increases from the RTP engine.

ASTERISK-24916 #close
Reported by Christophe Osuna

Change-Id: I9a90bc3f564535bc767bf2fc0c455d5f065cea75

diff --git a/main/rtp_engine.c b/main/rtp_engine.c
index 870ccc45ff08160506d4e77ff53a1d13f04b0b8f..b16b5de9681b9cb28259da11d5ddcc22fbae51cc 100644 (file)
--- a/main/rtp_engine.c
+++ b/main/rtp_engine.c
@@ -503,12 +503,19 @@ void ast_rtp_codecs_payloads_copy(struct ast_rtp_codecs *src, struct ast_rtp_cod
 
        for (i = 0; i < AST_RTP_MAX_PT; i++) {
                struct ast_rtp_payload_type *new_type;
+               int payload_alloced = 0;
 
                if (!(type = ao2_find(src->payloads, &i, OBJ_KEY | OBJ_NOLOCK))) {
                        continue;
                }
 
-               if (!(new_type = ao2_alloc(sizeof(*new_type), NULL))) {
+               new_type = ao2_find(dest->payloads, &i, OBJ_KEY | OBJ_NOLOCK);
+               if (!new_type) {
+                       new_type = ao2_alloc(sizeof(*new_type), NULL);
+                       payload_alloced = 1;
+               }
+
+               if (!new_type) {
                        continue;
                }
 
@@ -517,7 +524,9 @@ void ast_rtp_codecs_payloads_copy(struct ast_rtp_codecs *src, struct ast_rtp_cod
                new_type->payload = i;
                *new_type = *type;
 
-               ao2_link_flags(dest->payloads, new_type, OBJ_NOLOCK);
+               if (payload_alloced) {
+                       ao2_link_flags(dest->payloads, new_type, OBJ_NOLOCK);
+               }
 
                ao2_ref(new_type, -1);