From 39739c8437af139b5df89c03e3851a69bb562be1 Mon Sep 17 00:00:00 2001
From: Matej Sekoranja <matej.sekoranja@cosylab.com>
Date: Wed, 2 Mar 2016 22:24:22 +0100
Subject: [PATCH] fixed tricky UDP transport replayTo issue

---
 src/remote/blockingUDPTransport.cpp | 22 +++++++++-------------
 src/remote/pv/blockingUDP.h         |  7 +++++--
 2 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/src/remote/blockingUDPTransport.cpp b/src/remote/blockingUDPTransport.cpp
index 775718a..7a9cf2e 100644
--- a/src/remote/blockingUDPTransport.cpp
+++ b/src/remote/blockingUDPTransport.cpp
@@ -218,8 +218,7 @@ inline int sendto(int s, const char *buf, size_t len, int flags, const struct so
 
             osiSockAddr fromAddress;
             osiSocklen_t addrStructSize = sizeof(sockaddr);
-            Transport::shared_pointer thisTransport = shared_from_this(),
-                                      replyTo(_replyTransport ? _replyTransport : thisTransport);
+            Transport::shared_pointer thisTransport = shared_from_this();
 
             try {
 
@@ -227,13 +226,6 @@ inline int sendto(int s, const char *buf, size_t len, int flags, const struct so
                 size_t recvfrom_buffer_len =_receiveBuffer->getSize()-RECEIVE_BUFFER_PRE_RESERVE;
                 while(!_closed.get())
                 {
-                    // we poll to prevent blocking indefinitely
-
-                    // data ready to be read
-                    _receiveBuffer->clear();
-                    // reserve some space for CMD_ORIGIN_TAG
-                    _receiveBuffer->setPosition(RECEIVE_BUFFER_PRE_RESERVE);
-
                     int bytesRead = recvfrom(_channel,
                             recvfrom_buffer_start, recvfrom_buffer_len,
                             0, (sockaddr*)&fromAddress,
@@ -259,7 +251,7 @@ inline int sendto(int s, const char *buf, size_t len, int flags, const struct so
                             _receiveBuffer->setLimit(RECEIVE_BUFFER_PRE_RESERVE+bytesRead);
 
                             try{
-                                processBuffer(replyTo, fromAddress, _receiveBuffer.get());
+                                processBuffer(thisTransport, fromAddress, _receiveBuffer.get());
                             }catch(std::exception& e){
                                 LOG(logLevelError,
                                   "an exception caught while in UDP receiveThread at %s:%d: %s",
@@ -314,11 +306,13 @@ inline int sendto(int s, const char *buf, size_t len, int flags, const struct so
             _shutdownEvent.signal();
         }
 
-        bool BlockingUDPTransport::processBuffer(Transport::shared_pointer const & replyTransport,
+        bool BlockingUDPTransport::processBuffer(Transport::shared_pointer const & transport,
                                                  osiSockAddr& fromAddress, ByteBuffer* receiveBuffer) {
 
+
             // handle response(s)
             while(likely((int)receiveBuffer->getRemaining()>=PVA_MESSAGE_HEADER_SIZE)) {
+
                 //
                 // read header
                 //
@@ -398,7 +392,7 @@ inline int sendto(int s, const char *buf, size_t len, int flags, const struct so
                 else
                 {
                      // handle
-                    _responseHandler->handleResponse(&fromAddress, replyTransport,
+                    _responseHandler->handleResponse(&fromAddress, transport,
                             version, command, payloadSize,
                             _receiveBuffer.get());
                 }
@@ -668,8 +662,10 @@ inline int sendto(int s, const char *buf, size_t len, int flags, const struct so
                                                                 PVA_DEFAULT_PRIORITY));
                             /* The other wrinkle is that nothing should be sent from this second
                              * socket. So replies are made through the unicast socket.
-                             */
+                             *
                             transport2->setReplyTransport(transport);
+                            */
+                            // NOTE: search responses all always send from sendTransport
 
                             if (ignoreAddressVector.get() && ignoreAddressVector->size())
                                 transport2->setIgnoredAddresses(ignoreAddressVector.get());
diff --git a/src/remote/pv/blockingUDP.h b/src/remote/pv/blockingUDP.h
index c7791bf..af124b0 100644
--- a/src/remote/pv/blockingUDP.h
+++ b/src/remote/pv/blockingUDP.h
@@ -70,10 +70,12 @@ namespace epics {
                 return _closed.get();
             }
 
+            /*
             void setReplyTransport(const Transport::shared_pointer& T)
             {
                 _replyTransport = T;
             }
+            */
 
             virtual const osiSockAddr* getRemoteAddress() const {
                 return &_remoteAddress;
@@ -369,12 +371,13 @@ namespace epics {
              */
             SOCKET _channel;
 
-            /** When provided, this transport is used for replies (passed to handler)
+            /* When provided, this transport is used for replies (passed to handler)
              * instead of *this.  This feature is used in the situation where broadcast
              * traffic is received on one socket, but a different socket must be used
              * for unicast replies.
-             */
+             *
             Transport::shared_pointer _replyTransport;
+            */
 
             /**
              * Bind address.