From 55fdfc223ea0584ec88fb392f729e205c021ace2 Mon Sep 17 00:00:00 2001
From: Eric <ewild@sysmocom.de>
Date: Fri, 13 Aug 2021 00:14:18 +0200
Subject: [PATCH] globally lock the portrange when trying to grab a port to
 prep for multithreading

Change-Id: I78ae737b829bb428372f34db7d5bc601b5088b78
---
 configure.ac                     | 3 +++
 include/osmocom/mgcp/mgcp.h      | 2 ++
 src/libosmo-mgcp/mgcp_protocol.c | 6 +++++-
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 192c012ac..b996e87b0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -57,6 +57,9 @@ PKG_CHECK_MODULES(LIBOSMONETIF, libosmo-netif >= 1.1.0)
 PKG_CHECK_MODULES(LIBOSMOABIS, libosmoabis >= 1.1.0)
 PKG_CHECK_MODULES(LIBOSMOTRAU, libosmotrau >= 1.1.0)
 
+CFLAGS="$CFLAGS -pthread"
+LDFLAGS="$LDFLAGS -pthread"
+
 AC_ARG_ENABLE(sanitize,
 	[AS_HELP_STRING(
 		[--enable-sanitize],
diff --git a/include/osmocom/mgcp/mgcp.h b/include/osmocom/mgcp/mgcp.h
index b3f2eb5b0..228b0b3c5 100644
--- a/include/osmocom/mgcp/mgcp.h
+++ b/include/osmocom/mgcp/mgcp.h
@@ -34,6 +34,7 @@
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
+#include <pthread.h>
 
 #include "mgcp_ratectr.h"
 
@@ -92,6 +93,7 @@ typedef void (*mgcp_get_format)(struct mgcp_endpoint *endp,
  * This holds information on how to allocate ports
  */
 struct mgcp_port_range {
+	pthread_mutex_t lock;
 	/* addr or NULL to fall-back to default */
 	char *bind_addr_v4;
 	char *bind_addr_v6;
diff --git a/src/libosmo-mgcp/mgcp_protocol.c b/src/libosmo-mgcp/mgcp_protocol.c
index ba80d7d79..16b7dab1a 100644
--- a/src/libosmo-mgcp/mgcp_protocol.c
+++ b/src/libosmo-mgcp/mgcp_protocol.c
@@ -28,6 +28,7 @@
 #include <limits.h>
 #include <unistd.h>
 #include <errno.h>
+#include <pthread.h>
 
 #include <osmocom/core/msgb.h>
 #include <osmocom/core/talloc.h>
@@ -478,6 +479,7 @@ static int allocate_port(struct mgcp_endpoint *endp, struct mgcp_conn_rtp *conn)
 
 	range = &endp->cfg->net_ports;
 
+	pthread_mutex_lock(&range->lock);
 	/* attempt to find a port */
 	tries = (range->range_end - range->range_start) / 2;
 	for (i = 0; i < tries; ++i) {
@@ -490,11 +492,12 @@ static int allocate_port(struct mgcp_endpoint *endp, struct mgcp_conn_rtp *conn)
 
 		range->last_port += 2;
 		if (rc == 0) {
+			pthread_mutex_unlock(&range->lock);
 			return 0;
 		}
 
 	}
-
+	pthread_mutex_unlock(&range->lock);
 	LOGPENDP(endp, DLMGCP, LOGL_ERROR,
 	     "Allocating a RTP/RTCP port failed %u times.\n",
 	     tries);
@@ -1606,6 +1609,7 @@ struct mgcp_config *mgcp_config_alloc(void)
 
 	osmo_strlcpy(cfg->domain, "mgw", sizeof(cfg->domain));
 
+	cfg->net_ports.lock = (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER;
 	cfg->net_ports.range_start = RTP_PORT_DEFAULT_RANGE_START;
 	cfg->net_ports.range_end = RTP_PORT_DEFAULT_RANGE_END;
 	cfg->net_ports.last_port = cfg->net_ports.range_start;