Harald Welte 563ffc51b5 libosmo-mgcp-client: fix memleak in case if no response is received
This problem was noticed while running several LCLS test cases from
ttcn3-bsc-test.  Every test case makes osmo-bsc leak at least two
chunks named 'struct mgcp_response_pending'.

Here is the related osmo-bsc output with additional debug messages:

  DRLL ERROR mgcp_client_fsm.c:525 MGCP_CONN(to-MSC)[0x612000016120]{ST_READY}:
             MGW/DLCX: abrupt FSM termination with connections still present,
             sending unconditional DLCX...
  DLMGCP DEBUG mgcp_client.c:1010 mgcp_client_next_trans_id(id=35): new trans ID
  DLMGCP DEBUG mgcp_client.c:918 mgcp_client_pending_add(id=35): allocated and queued
  DLMGCP DEBUG mgcp_client.c:962 Queued 53 bytes for MGCP GW
  DLMGCP DEBUG mgcp_client.c:725 Tx MGCP: r=127.0.0.1:2427<->l=127.0.0.1:2727:
               len=53 'DLCX 35 rtpbridge/1@mgw MGCP 1.0\r\nC: 5\r\nI:'...
  DLMGCP ERROR mgcp_client.c:704 Failed to read: r=127.0.0.1:2427<->l=127.0.0.1:2727:
               111='Connection refused'

The MGCP client FSM enqueues a DLCX from its fsm_cleanup_cb(), and
terminates.  Thus if the remote MGCP peer becomes unavailable (e.g.
due to a network failure), we would never get a response, and since
the FSM is already terminated, nobody would pop and free() the
response handler from the queue (mgcp->responses_pending).

As a simple workaround, let's avoid allocating dummy entries of
'struct mgcp_response_pending' without a response handler.  The
only case where an MGCP message is sent without a handler is
exactly during the FSM termination.

Change-Id: I83938ff47fa8570b8d9dc810a184864a0c0b58aa
Related: OS#4619
2020-07-31 10:21:49 +00:00
2017-08-27 17:44:55 +02:00
2020-05-19 15:33:19 +02:00
2017-08-27 17:44:55 +02:00
2020-05-19 15:33:19 +02:00
2017-08-27 17:44:55 +02:00
2017-08-27 17:44:55 +02:00

About OsmoMGW
=============

OsmoMGW originated from the OpenBSC project, which started as a minimalistic
all-in-one implementation of the GSM Network. In 2017, OpenBSC had reached
maturity and diversity (including M3UA SIGTRAN and 3G support in the form of
IuCS and IuPS interfaces) that naturally lead to a separation of the all-in-one
approach to fully independent separate programs as in typical GSM networks.

OsmoMGW was one of the parts split off from the old openbsc.git. It originated
as a solution to merely navigate RTP streams through a NAT, but has since
matured to a Media Gateway implementation that is capable of streaming RTP for
2G (AoIP) and 3G (IuCS) GSM networks as well as (still not implemented at time
of writing) transcoding between TRAU, various RTP payloads and IuUP.

The OsmoMGW program exposes an MGCP interface towards clients like OsmoMSC and
OsmoBSC, and receives and sends RTP streams as configured via MGCP.

The libosmo-mgcp-client library exposes utilities used by e.g. OsmoMSC (found
in osmo-msc.git) to instruct OsmoMGW via its MGCP service.

Find OsmoMGW issue tracker and wiki online at
https://osmocom.org/projects/osmo-mgw
https://osmocom.org/projects/osmo-mgw/wiki
Description
Osmocom Media Gateway (RTP proxy and RTP/E1 gateway)
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