Computation of buffer size for PGM fixed.

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

src/pgm_socket.cpp

@@ -151,8 +151,9 @@ int zmq::pgm_socket_t::init (bool udp_encapsulation_, const char *network_)
         //  All options are of data type int
         const int encapsulation_port = port_number;
         if (!pgm_setsockopt (sock, IPPROTO_PGM, PGM_UDP_ENCAP_UCAST_PORT,
-                &encapsulation_port, sizeof (encapsulation_port)) ||
-            !pgm_setsockopt (sock, IPPROTO_PGM, PGM_UDP_ENCAP_MCAST_PORT,
+                &encapsulation_port, sizeof (encapsulation_port)))
+            goto err_abort;
+        if (!pgm_setsockopt (sock, IPPROTO_PGM, PGM_UDP_ENCAP_MCAST_PORT,
                 &encapsulation_port, sizeof (encapsulation_port)))
             goto err_abort;
     }
@@ -200,11 +201,7 @@ int zmq::pgm_socket_t::init (bool udp_encapsulation_, const char *network_)
     if (receiver) {
         const int recv_only        = 1,
                   rxw_max_tpdu     = (int) pgm_max_tpdu,
-                  rxw_sqns         = (options.recovery_ivl_msec >= 0 ?
-                                      options.recovery_ivl_msec * options.rate /
-                                      (1000 * rxw_max_tpdu) :
-                                      options.recovery_ivl * options.rate /
-                                      rxw_max_tpdu),
+                  rxw_sqns         = compute_sqns (rxw_max_tpdu),
                   peer_expiry      = pgm_secs (300),
                   spmr_expiry      = pgm_msecs (25),
                   nak_bo_ivl       = pgm_msecs (50),
@@ -235,11 +232,7 @@ int zmq::pgm_socket_t::init (bool udp_encapsulation_, const char *network_)
     } else {
         const int send_only        = 1,
                   txw_max_tpdu     = (int) pgm_max_tpdu,
-                  txw_sqns         = (options.recovery_ivl_msec >= 0 ?
-                                      options.recovery_ivl_msec * options.rate /
-                                      (1000 * txw_max_tpdu) :
-                                      options.recovery_ivl * options.rate /
-                                      txw_max_tpdu),
+                  txw_sqns         = compute_sqns (txw_max_tpdu),
                   ambient_spm      = pgm_secs (30),
                   heartbeat_spm[]  = { pgm_msecs (100),
                                        pgm_msecs (100),
@@ -680,5 +673,29 @@ void zmq::pgm_socket_t::process_upstream ()
         errno = EAGAIN;
 }
 
+int zmq::pgm_socket_t::compute_sqns (int tpdu_)
+{
+    //  Convert rate into B/ms.
+    uint64_t rate = ((uint64_t) options.rate) / 8;
+
+    //  Get recovery interval in milliseconds.
+    uint64_t interval = options.recovery_ivl_msec >= 0 ?
+        options.recovery_ivl_msec :
+        options.recovery_ivl * 1000;
+        
+    //  Compute the size of the buffer in bytes.
+    uint64_t size = interval * rate;
+
+    //  Translate the size into number of packets.
+    uint64_t sqns = size / tpdu_;
+    zmq_assert (sqns >= 0);
+
+    //  Buffer should be able to contain at least one packet.
+    if (sqns == 0)
+        sqns = 1;
+
+    return sqns;
+}
+
 #endif
 

src/pgm_socket.hpp

@@ -80,6 +80,9 @@ namespace zmq
         void process_upstream ();
 
     private:
+
+        //  Compute size of the buffer based on rate and recovery interval.
+        int compute_sqns (int tpdu_);
     
         //  OpenPGM transport.
         pgm_sock_t* sock;