Add API to limit retransmission count for outgoing requests in transaction layer

pjsip/include/pjsip/sip_transaction.h

@@ -454,23 +454,49 @@ PJ_DECL(pj_status_t) pjsip_tsx_stop_retransmit(pjsip_transaction *tsx);
 PJ_DECL(pj_status_t) pjsip_tsx_set_timeout(pjsip_transaction *tsx,
                                            unsigned millisec);
 
+
 /**
  * Change timer values used by transaction layer. Currently scheduled
  * timers will not be changed. Any value set to 0 will be left
  * unchanged.
  *
- * @param t1 - Transaction T1 timeout, in msec
- * @param t2 - Transaction T2 timeout, in msec
- * @param t4 - Transaction completed timer for non-INVITE, in msec
- * @param td - Transaction completed timer for INVITE, in msec
+ * @param t1        Transaction T1 timeout, in msec
+ * @param t2        Transaction T2 timeout, in msec
+ * @param t4        Transaction completed timer for non-INVITE, in msec
+ * @param td        Transaction completed timer for INVITE, in msec
  */
-PJ_DECL(void) pjsip_tsx_set_timers(unsigned t1, unsigned t2, unsigned t4, unsigned td);
+PJ_DECL(void) pjsip_tsx_set_timers(unsigned t1, unsigned t2, unsigned t4,
+                                   unsigned td);
+
 
 /**
  * (Re)Initializes timer values from pjsip_cfg().
  */
 PJ_DECL(void) pjsip_tsx_initialize_timer_values(void);
 
+
+/**
+ * Set maximum retransmission count in transaction layer for outgoing
+ * requests. When retransmission counter reaches the specified number,
+ * the transaction will be considered timeout. This will affect any
+ * ongoing transactions immediately.
+ *
+ * By default (or when this is set to -1), retransmission number will
+ * not cause a transaction to be timeout, only the timer settings will
+ * cause transaction timeout. Also, this will not override the timer
+ * settings, i.e: if the timeout timer occurs before the maximum
+ * retransmission is reached, the transaction will still gets timeout.
+ *
+ * When this is set to zero or possitive number P, a transaction timeout
+ * will occur right before the retransmission number (P+1). For example,
+ * if this is set to 1 there will be two transmissions: the initial
+ * transmission and one retransmission, before the transaction gets timeout.
+ *
+ * @param max       Maximum retransmission count.
+ */
+PJ_DECL(void) pjsip_tsx_set_max_retransmit_count(int max);
+
+
 /**
  * Get the transaction instance in the incoming message. If the message
  * has a corresponding transaction, this function will return non NULL

pjsip/src/pjsip/sip_transaction.c

@@ -132,6 +132,7 @@ static pj_time_val td_timer_val = { PJSIP_TD_TIMEOUT/1000,
                                     PJSIP_TD_TIMEOUT%1000 };
 static pj_time_val timeout_timer_val = { (64*PJSIP_T1_TIMEOUT)/1000,
                                          (64*PJSIP_T1_TIMEOUT)%1000 };
+static int max_retrans_count = -1;
 
 #define TIMER_INACTIVE          0
 #define RETRANSMIT_TIMER        1
@@ -479,6 +480,13 @@ PJ_DEF(void) pjsip_tsx_initialize_timer_values(void)
     timeout_timer_val = td_timer_val;
 }
 
+
+PJ_DEF(void) pjsip_tsx_set_max_retransmit_count(int max)
+{
+    max_retrans_count = max;
+}
+
+
 /*****************************************************************************
  **
  ** Transaction layer module
@@ -499,6 +507,9 @@ PJ_DEF(pj_status_t) pjsip_tsx_layer_init_module(pjsip_endpoint *endpt)
     /* Initialize timer values */
     pjsip_tsx_initialize_timer_values();
 
+    /* Reset max retrans count (for library restart scenario) */
+    max_retrans_count = -1;
+
     /*
      * Initialize transaction layer structure.
      */
@@ -2562,6 +2573,26 @@ static pj_status_t tsx_retransmit( pjsip_transaction *tsx, int resched)
 
     PJ_ASSERT_RETURN(tsx->last_tx!=NULL, PJ_EBUG);
 
+    /* If max retransmission count is reached, put it as timeout */
+    if (max_retrans_count >= 0 &&
+        tsx->retransmit_count >= max_retrans_count &&
+        tsx->last_tx->msg->type == PJSIP_REQUEST_MSG)
+    {
+        pj_time_val timeout = { 0, 0 };
+
+        PJ_LOG(3,(tsx->obj_name,
+                  "Stop retransmiting %s, max retrans %d reached, "
+                  "tsx set as timeout",
+                  pjsip_tx_data_get_info(tsx->last_tx),
+                  tsx->retransmit_count));
+
+        lock_timer(tsx);
+        tsx_cancel_timer( tsx, &tsx->timeout_timer );
+        tsx_schedule_timer(tsx, &tsx->timeout_timer, &timeout, TIMEOUT_TIMER);
+        unlock_timer(tsx);
+        return PJ_SUCCESS;
+    }
+
     PJ_LOG(5,(tsx->obj_name, "Retransmiting %s, count=%d, restart?=%d", 
               pjsip_tx_data_get_info(tsx->last_tx), 
               tsx->retransmit_count, resched));