- improvements on RTP proxy for proxying a "looped" call

(means originating from local UA , via external registrar
  back to another local UA)

ChangeLog

@@ -1,6 +1,9 @@
 0.6.0
 =====
   29-May-2007:  - Deal with PRACK requests (RFC3262)
+                - improvements on RTP proxy for proxying a "looped" call
+                  (means originating from local UA , via external registrar
+                  back to another local UA)
   25-May-2007:  - Just discovered some patches originating from Debian
                   project - included most of them as they make sense.
                   (Hint: People, if you get fixes, please drop me a note

src/proxy.c

@@ -817,28 +817,15 @@ int proxy_rewrite_invitation_body(sip_ticket_t *ticket, int direction){
     */
    sts = osip_message_get_body(mymsg, 0, &body);
    if (sts != 0) {
-#if 0
-      if ((MSG_IS_RESPONSE_FOR(mymsg,"INVITE")) &&
-          (MSG_IS_STATUS_1XX(mymsg))) {
-         /* 1xx responses *MAY* contain SDP data */
-         DEBUGC(DBCLASS_PROXY, "rewrite_invitation_body: "
-                "no body found in message");
-         return STS_SUCCESS;
-      } else {
-         /* INVITE request and 200 response *MUST* contain SDP data */
-         ERROR("rewrite_invitation_body: no body found in message");
-         return STS_FAILURE;
-      }
-#else
       DEBUGC(DBCLASS_PROXY, "rewrite_invitation_body: "
                             "no body found in message");
       return STS_SUCCESS;
-#endif
    }
 
    sts = sip_body_to_str(body, &buff, &buflen);
    if (sts != 0) {
       ERROR("rewrite_invitation_body: unable to sip_body_to_str");
+      return STS_FAILURE;
    }
 
    DEBUGC(-1, "rewrite_invitation_body: payload %ld bytes", (long)buflen);
@@ -1017,8 +1004,8 @@ if (configuration.debuglevel)
       if (sdp_message_m_port_get(sdp, media_stream_no)) {
          msg_port=atoi(sdp_message_m_port_get(sdp, media_stream_no));
          if ((msg_port > 0) && (msg_port <= 65535)) {
-            char *client_id=NULL;
+            client_id_t client_id;
-            static char from_string[HOSTNAME_SIZE];
+            osip_contact_t *contact = NULL;
             char *tmp=NULL;
             char *protocol=NULL;
 
@@ -1028,10 +1015,35 @@ if (configuration.debuglevel)
              * particular Header (Contact) or not.
              * I should just go for the remote IP address here, no?
              */
-            tmp=utils_inet_ntoa(ticket->from.sin_addr);
+            /* &&& NO, using the sender IP will cause troubles if
-            strncpy(from_string, tmp, HOSTNAME_SIZE);
+             * the remote peer (Proxy/registrar) is thrown out of
-            from_string[HOSTNAME_SIZE-1]='\0';
+             * the signalling path. Then suddenly the IP address changes.
-            client_id=from_string;
+             *
+             * I should probably go back to the Contact Header based idea,
+             * with fallback to IP.
+             * I must use a n-item structure, including all things that
+             * can be used for comparing. Then, in the RTP proxy, comparison
+             * must take place according to priorities with the item
+             * with highest priority present in the RTP table *and*
+             * extracted from the SIP message.
+             * To start with, this can be just 2 things, the Contact header
+             * and the Layer 3 IP address. As long as the UAs include the
+             * Contact header, we survive IP changes (e.g. when the SIP
+             * Registrar/Proxy is removed from signalling path within an
+             * ongoing call. This may happen if the Registrar/Proxy does
+             * not explicitely ask to stay in the signalling path using 
+             * Record-Route headers - which is perfectly legal
+             *
+             */
+
+            /* get the Contact Header if present */
+            osip_message_get_contact(mymsg, 0, &contact);
+            osip_contact_to_str(contact, &tmp);
+            strcpy(client_id.contact, tmp);
+
+            /* store the IP address of the sender */
+            memcpy(&client_id.from_ip, &ticket->from.sin_addr,
+                   sizeof(client_id.from_ip));
 
             /*
              * is this an RTP stream ? If yes, set 'isrtp=1'

src/rtpproxy.c

@@ -72,7 +72,7 @@ int rtpproxy_init( void ) {
  *	STS_SUCCESS on success
  *	STS_FAILURE on error
  */
-int rtp_start_fwd (osip_call_id_t *callid, char *client_id,
+int rtp_start_fwd (osip_call_id_t *callid, client_id_t client_id,
                    int direction, int media_stream_no,
                    struct in_addr local_ipaddr, int *local_port,
                    struct in_addr remote_ipaddr, int remote_port,

src/rtpproxy.h

@@ -22,7 +22,6 @@
 
 #define CALLIDNUM_SIZE	256
 #define CALLIDHOST_SIZE	128
-#define CLIENT_ID_SIZE	128
 
 typedef struct {
 	struct timeval		starttime ;
@@ -42,11 +41,11 @@ typedef struct {
 typedef struct {
    int  rtp_rx_sock;				/* rx socket (0 -> free slot)*/
    int  rtp_tx_sock;				/* tx socket */
-   int rtp_con_rx_sock;				/* rx socket rtcp */
+   int  rtp_con_rx_sock;			/* rx socket rtcp */
-   int rtp_con_tx_sock;				/* tx socket rtcp */
+   int  rtp_con_tx_sock;			/* tx socket rtcp */
    char callid_number[CALLIDNUM_SIZE];		/* call ID */
    char callid_host[CALLIDHOST_SIZE];		/*  --"--  */
-   char client_id[CLIENT_ID_SIZE];
+   client_id_t client_id;
    int  direction;				/* Direction of RTP stream */
    int  media_stream_no;
    timecontrol_t tc;
@@ -62,7 +61,7 @@ typedef struct {
  * RTP relay
  */
 int  rtp_relay_init(void);
-int  rtp_relay_start_fwd (osip_call_id_t *callid, char *client_id,
+int  rtp_relay_start_fwd (osip_call_id_t *callid, client_id_t client_id,
                           int rtp_direction, int media_stream_no,
                           struct in_addr local_ipaddr, int *local_port,
                           struct in_addr remote_ipaddr, int remote_port,

src/rtpproxy_relay.c

@@ -441,7 +441,7 @@ static void *rtpproxy_main(void *arg) {
  *	STS_SUCCESS on success
  *	STS_FAILURE on error
  */
-int rtp_relay_start_fwd (osip_call_id_t *callid, char *client_id,
+int rtp_relay_start_fwd (osip_call_id_t *callid, client_id_t client_id,
                          int rtp_direction,
                          int media_stream_no, struct in_addr local_ipaddr,
                          int *local_port, struct in_addr remote_ipaddr,
@@ -461,11 +461,6 @@ int rtp_relay_start_fwd (osip_call_id_t *callid, char *client_id,
       return STS_FAILURE;
    }
 
-   if (client_id == NULL) {
-      ERROR("rtp_relay_start_fwd: did not get a client ID!");
-      return STS_FAILURE;
-   }
-
    /*
     * life insurance: check size of received call_id strings
     * I don't know what the maximum allowed size within SIP is,
@@ -484,16 +479,10 @@ int rtp_relay_start_fwd (osip_call_id_t *callid, char *client_id,
             callid->host, (long)strlen(callid->host),CALLIDHOST_SIZE);
       return STS_FAILURE;
    }
-   if (client_id && (strlen(client_id) >= CLIENT_ID_SIZE)) {
-      ERROR("rtp_relay_start_fwd: client ID [%s] has too many characters "
-            "(%ld, max=%i)",
-            client_id, (long)strlen(client_id),CLIENT_ID_SIZE);
-      return STS_FAILURE;
-   }
 
    DEBUGC(DBCLASS_RTP,"rtp_relay_start_fwd: starting RTP proxy "
-          "stream for: %s@%s[%s] (%s) #=%i",
+          "stream for: CallID=%s@%s [Client-ID=%s] (%s) #=%i",
-          callid->number, callid->host, client_id,
+          callid->number, callid->host, client_id.contact,
           ((rtp_direction == DIR_INCOMING) ? "incoming RTP" : "outgoing RTP"),
           media_stream_no);
 
@@ -522,7 +511,8 @@ int rtp_relay_start_fwd (osip_call_id_t *callid, char *client_id,
          (compare_callid(callid, &cid) == STS_SUCCESS) &&
          (rtp_proxytable[i].direction == rtp_direction) &&
          (rtp_proxytable[i].media_stream_no == media_stream_no) &&
-         (strcmp(rtp_proxytable[i].client_id, client_id) == 0)) {
+         (compare_client_id(rtp_proxytable[i].client_id, client_id) ==
+            STS_SUCCESS)) {
          /*
           * The RTP port number reported by the UA MAY change
           * for a given media stream
@@ -696,11 +686,8 @@ int rtp_relay_start_fwd (osip_call_id_t *callid, char *client_id,
       rtp_proxytable[freeidx].callid_host[0]='\0';
    }
 
-   if (client_id) {
+   /* store the passed Client-ID data */
-      strcpy(rtp_proxytable[freeidx].client_id, client_id);
+   memcpy(&rtp_proxytable[freeidx].client_id, &client_id, sizeof(client_id_t));
-   } else {
-      rtp_proxytable[freeidx].client_id[0]='\0';
-   }
 
    rtp_proxytable[freeidx].direction = rtp_direction;
    rtp_proxytable[freeidx].media_stream_no = media_stream_no;
@@ -741,10 +728,10 @@ int rtp_relay_start_fwd (osip_call_id_t *callid, char *client_id,
 
 //&&&
    DEBUGC(DBCLASS_RTP,"rtp_relay_start_fwd: started RTP proxy "
-          "stream for: %s@%s[%s] (%s) #=%i idx=%i",
+          "stream for: CallID=%s@%s [Client-ID=%s] %s #=%i idx=%i",
           rtp_proxytable[freeidx].callid_number,
           rtp_proxytable[freeidx].callid_host,
-          rtp_proxytable[freeidx].client_id,
+          rtp_proxytable[freeidx].client_id.contact,
           ((rtp_proxytable[freeidx].direction == DIR_INCOMING) ? "incoming RTP" : "outgoing RTP"),
           rtp_proxytable[freeidx].media_stream_no, freeidx);
 

src/siproxd.h

@@ -117,6 +117,18 @@ typedef struct {
 } sip_ticket_t;
 
 
+/*
+ * Client_ID - used to identify the two sides of a Call when one
+ * call is routed twice (in->out and back out->in) through siproxd
+ * e.g. local UA1 is calling local UA2 via an external Registrar
+ */
+#define CLIENT_ID_SIZE	128
+typedef struct {
+   char    contact[CLIENT_ID_SIZE];
+   struct  in_addr from_ip;
+   /*... maybe more to come ...*/
+} client_id_t;
+
 
 /*
  * Function prototypes
@@ -164,6 +176,7 @@ int  get_interface_ip(int interface, struct in_addr *retaddr);		/*X*/
 char *utils_inet_ntoa(struct in_addr in);
 int  utils_inet_aton(const char *cp, struct in_addr *inp);
 int  createpidfile(char *pidfilename);					/*X*/
+int  compare_client_id(client_id_t cid1, client_id_t cid2);		/*X*/
 
 /* sip_utils.c */
 osip_message_t * msg_make_template_reply (sip_ticket_t *ticket, int code);
@@ -189,7 +202,7 @@ int make_default_config(void);						/*X*/
 
 /* rtpproxy.c */
 int  rtpproxy_init( void );						/*X*/
-int  rtp_start_fwd (osip_call_id_t *callid, char *client_id,            /*X*/
+int  rtp_start_fwd (osip_call_id_t *callid, client_id_t client_id,	/*X*/
                     int direction, int media_stream_no,
                     struct in_addr outbound_ipaddr, int *outboundport,
                     struct in_addr lcl_client_ipaddr, int lcl_clientport,
@@ -246,8 +259,8 @@ int sip_message_set_body(osip_message_t * sip, const char *buf, size_t len);
 				/* (assume approx one Ethernet MTU)	*/
 
 #define URL_STRING_SIZE	128	/* max size of an URL/URI string	*/
-#define STATUSCODE_SIZE 5	/* size of string representation of status */
+#define STATUSCODE_SIZE	5	/* size of string representation of status */
-#define DNS_CACHE_SIZE  256	/* number of entries in internal DNS cache */
+#define DNS_CACHE_SIZE	256	/* number of entries in internal DNS cache */
 #define DNS_MAX_AGE	60	/* maximum age of an cache entry (sec)	*/
 #define IFADR_CACHE_SIZE 32	/* number of entries in internal IFADR cache */
 #define IFADR_MAX_AGE	5	/* max. age of the IF address cache (sec) */
@@ -255,8 +268,9 @@ int sip_message_set_body(osip_message_t * sip, const char *buf, size_t len);
 #define HOSTNAME_SIZE	128	/* max string length of a hostname	*/
 #define USERNAME_SIZE	128	/* max string length of a username (auth) */
 #define PASSWORD_SIZE	128	/* max string length of a password (auth) */
-#define VIA_BRANCH_SIZE 128	/* max string length for via branch param */
+#define VIA_BRANCH_SIZE	128	/* max string length for via branch param */
 				/* scratch buffer for gethostbyname_r() */
+
 #if defined(PR_NETDB_BUF_SIZE)
    #define GETHOSTBYNAME_BUFLEN PR_NETDB_BUF_SIZE 
 #else

src/utils.c

@@ -526,3 +526,32 @@ int createpidfile(char *pidfilename) {
    return STS_SUCCESS;
 }
 
+
+/*
+ *
+ *
+ */
+int  compare_client_id(client_id_t cid1, client_id_t cid2) {
+
+   /* Prio 1: Contact - if present */
+   if ((cid1.contact[0] != '\0') && (cid2.contact[0] != '\0')) {
+      if (strcmp(cid1.contact, cid2.contact) == 0) {
+         DEBUGC(DBCLASS_BABBLE, "compare_client_id: contact match [%s]",
+                cid1.contact);
+         return STS_SUCCESS;
+      }
+      DEBUGC(DBCLASS_BABBLE, "compare_client_id: contact NO match [%s<->%s]",
+             cid1.contact, cid2.contact);
+      return STS_FAILURE;
+   }
+
+   /* Prio 2: IP (always present) */
+   if (memcmp(&cid1.from_ip, &cid2.from_ip, sizeof(struct in_addr)) == 0) {
+      DEBUGC(DBCLASS_BABBLE, "compare_client_id: IP match [%s]",
+             utils_inet_ntoa(cid1.from_ip));
+      return STS_SUCCESS;
+   }
+
+   DEBUGC(DBCLASS_BABBLE, "compare_client_id: no match");
+   return STS_FAILURE;
+}