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Bug #2433

Drop MGCP_DUMMY_LOAD frames and use proper Osmux Dummy frames

Added by pespin 7 days ago.

Status:
New
Priority:
Normal
Assignee:
Category:
-
Target version:
-
Start date:
08/11/2017
Due date:
% Done:

0%

Spec Reference:

Description

In some places we are using some manually crafted dummy packets with payload = 0x23 = MGCP_DUMMY_LOAD. With latest wireshark versions, those packets are recognized as "Osmux AMR Old Dummy".
However, Osmux supports Dummy frames with its own FT type (2). Better analyze and drop these crafted MGCP_DUMMY_LOAD and use proper Dummy frames as explained on the reference osmux doc (http://ftp.osmocom.org/docs/latest/osmux-reference.pdf).

Add APIs if needed to send some dummy packet instantly or similar.

$ ag MGCP_DUMMY_LOAD
openbsc/tests/mgcp/mgcp_test.c
443:#define MGCP_DUMMY_LOAD 0x23
458:    if (len == 1 && ((const char *)buf)[0] == MGCP_DUMMY_LOAD ) {

openbsc/src/libmgcp/mgcp_network.c
95:     static char buf[] = { MGCP_DUMMY_LOAD };
705:    if (rc == 1 && buf[0] == MGCP_DUMMY_LOAD) {
797:    if (rc == 1 && buf[0] == MGCP_DUMMY_LOAD) {
859:    if (rc == 1 && buf[0] == MGCP_DUMMY_LOAD) {

openbsc/src/libmgcp/mgcp_osmux.c
280:    if (msg->data[0] == MGCP_DUMMY_LOAD)
373:    if (msg->data[0] == MGCP_DUMMY_LOAD)
517:    buf[0] = MGCP_DUMMY_LOAD;

openbsc/include/openbsc/mgcp_internal.h
308:#define MGCP_DUMMY_LOAD 0x23

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