Fix: Bind RTP/RTCP socket pairs correctly

diff --git a/sip.cpp b/sip.cpp
index 7d16328..9081824 100644 (file)
--- a/sip.cpp
+++ b/sip.cpp
@@ -313,7 +313,8 @@ static int rtcp_sock_callback(struct lcr_fd *fd, unsigned int what, void *instan
 }
 
 #define RTP_PORT_BASE  30000
 }
 
 #define RTP_PORT_BASE  30000

-static unsigned int next_udp_port = RTP_PORT_BASE;
+#define RTP_PORT_MAX   39998
+static unsigned short next_udp_port = RTP_PORT_BASE;

 
 static int rtp_sub_socket_bind(int fd, struct sockaddr_in *sin_local, uint32_t ip, uint16_t port)
 {
 
 static int rtp_sub_socket_bind(int fd, struct sockaddr_in *sin_local, uint32_t ip, uint16_t port)
 {


@@ -353,13 +354,14 @@ static int rtp_sub_socket_connect(int fd, struct sockaddr_in *sin_local, struct
 
 int Psip::rtp_open(void)
 {
 
 int Psip::rtp_open(void)
 {

-       int rc;
+       int rc, rc2;

        struct in_addr ia;
        unsigned int ip;
        struct in_addr ia;
        unsigned int ip;

+       unsigned short start_port;

 
        /* create socket */
        rc = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
 
        /* create socket */
        rc = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

-       if (!rc) {
+       if (rc < 0) {

                rtp_close();
                return -EIO;
        }
                rtp_close();
                return -EIO;
        }


@@ -367,7 +369,7 @@ int Psip::rtp_open(void)
        register_fd(&p_s_rtp_fd, LCR_FD_READ, rtp_sock_callback, this, 0);
 
        rc = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
        register_fd(&p_s_rtp_fd, LCR_FD_READ, rtp_sock_callback, this, 0);
 
        rc = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

-       if (!rc) {
+       if (rc < 0) {

                rtp_close();
                return -EIO;
        }
                rtp_close();
                return -EIO;
        }


@@ -377,15 +379,34 @@ int Psip::rtp_open(void)
        /* bind socket */
        ip = htonl(INADDR_ANY);
        ia.s_addr = ip;
        /* bind socket */
        ip = htonl(INADDR_ANY);
        ia.s_addr = ip;

-       for (next_udp_port = next_udp_port % 0xffff;
-            next_udp_port < 0xffff; next_udp_port += 2) {
+       start_port = next_udp_port;
+       while (1) {

                rc = rtp_sub_socket_bind(p_s_rtp_fd.fd, &p_s_rtp_sin_local, ip, next_udp_port);
                if (rc != 0)
                rc = rtp_sub_socket_bind(p_s_rtp_fd.fd, &p_s_rtp_sin_local, ip, next_udp_port);
                if (rc != 0)

-                       continue;
+                       goto try_next_port;

 
                rc = rtp_sub_socket_bind(p_s_rtcp_fd.fd, &p_s_rtcp_sin_local, ip, next_udp_port+1);
 
                rc = rtp_sub_socket_bind(p_s_rtcp_fd.fd, &p_s_rtcp_sin_local, ip, next_udp_port+1);

-               if (rc == 0)
+               if (rc == 0) {
+                       next_udp_port = (next_udp_port + 2 > RTP_PORT_MAX) ? RTP_PORT_BASE : next_udp_port + 2;
+                       break;
+               }
+               /* reopen rtp socket and try again with next udp port */
+               unregister_fd(&p_s_rtp_fd);
+               close(p_s_rtp_fd.fd);
+               p_s_rtp_fd.fd = 0;
+               rc2 = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+               if (rc2 < 0) {
+                       rtp_close();
+                       return -EIO;
+               }
+               p_s_rtp_fd.fd = rc2;
+               register_fd(&p_s_rtp_fd, LCR_FD_READ, rtp_sock_callback, this, 0);
+
+try_next_port:
+               next_udp_port = (next_udp_port + 2 > RTP_PORT_MAX) ? RTP_PORT_BASE : next_udp_port + 2;
+               if (next_udp_port == start_port)

                        break;
                        break;

+               /* we must use rc2, in order to preserve rc */

        }
        if (rc < 0) {
                PDEBUG(DEBUG_SIP, "failed to find port\n");
        }
        if (rc < 0) {
                PDEBUG(DEBUG_SIP, "failed to find port\n");