From 9a0b784deaab6b9fffcab227d928987b981d0572 Mon Sep 17 00:00:00 2001
From: Cory Fields <cory-nospam-@coryfields.com>
Date: Mon, 6 Feb 2017 14:05:45 -0500
Subject: net: add a lock around hSocket

---
 src/net.cpp | 43 ++++++++++++++++++++++++++++---------------
 src/net.h   |  1 +
 2 files changed, 29 insertions(+), 15 deletions(-)

diff --git a/src/net.cpp b/src/net.cpp
index b47514fd92..2625cccaa3 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -425,6 +425,7 @@ void CConnman::DumpBanlist()
 void CNode::CloseSocketDisconnect()
 {
     fDisconnect = true;
+    LOCK(cs_hSocket);
     if (hSocket != INVALID_SOCKET)
     {
         LogPrint("net", "disconnecting peer=%d\n", id);
@@ -789,7 +790,13 @@ size_t CConnman::SocketSendData(CNode *pnode) const
     while (it != pnode->vSendMsg.end()) {
         const auto &data = *it;
         assert(data.size() > pnode->nSendOffset);
-        int nBytes = send(pnode->hSocket, reinterpret_cast<const char*>(data.data()) + pnode->nSendOffset, data.size() - pnode->nSendOffset, MSG_NOSIGNAL | MSG_DONTWAIT);
+        int nBytes = 0;
+        {
+            LOCK(pnode->cs_hSocket);
+            if (pnode->hSocket == INVALID_SOCKET)
+                break;
+            nBytes = send(pnode->hSocket, reinterpret_cast<const char*>(data.data()) + pnode->nSendOffset, data.size() - pnode->nSendOffset, MSG_NOSIGNAL | MSG_DONTWAIT);
+        }
         if (nBytes > 0) {
             pnode->nLastSend = GetSystemTimeInSeconds();
             pnode->nSendBytes += nBytes;
@@ -1150,9 +1157,6 @@ void CConnman::ThreadSocketHandler()
             LOCK(cs_vNodes);
             BOOST_FOREACH(CNode* pnode, vNodes)
             {
-                if (pnode->hSocket == INVALID_SOCKET)
-                    continue;
-
                 // Implement the following logic:
                 // * If there is data to send, select() for sending data. As this only
                 //   happens when optimistic write failed, we choose to first drain the
@@ -1171,6 +1175,10 @@ void CConnman::ThreadSocketHandler()
                     select_send = !pnode->vSendMsg.empty();
                 }
 
+                LOCK(pnode->cs_hSocket);
+                if (pnode->hSocket == INVALID_SOCKET)
+                    continue;
+
                 FD_SET(pnode->hSocket, &fdsetError);
                 hSocketMax = std::max(hSocketMax, pnode->hSocket);
                 have_fds = true;
@@ -1237,18 +1245,27 @@ void CConnman::ThreadSocketHandler()
             bool recvSet = false;
             bool sendSet = false;
             bool errorSet = false;
-            if (pnode->hSocket == INVALID_SOCKET)
-                continue;
-            recvSet = FD_ISSET(pnode->hSocket, &fdsetRecv);
-            sendSet = FD_ISSET(pnode->hSocket, &fdsetSend);
-            errorSet = FD_ISSET(pnode->hSocket, &fdsetError);
+            {
+                LOCK(pnode->cs_hSocket);
+                if (pnode->hSocket == INVALID_SOCKET)
+                    continue;
+                recvSet = FD_ISSET(pnode->hSocket, &fdsetRecv);
+                sendSet = FD_ISSET(pnode->hSocket, &fdsetSend);
+                errorSet = FD_ISSET(pnode->hSocket, &fdsetError);
+            }
             if (recvSet || errorSet)
             {
                 {
                     {
                         // typical socket buffer is 8K-64K
                         char pchBuf[0x10000];
-                        int nBytes = recv(pnode->hSocket, pchBuf, sizeof(pchBuf), MSG_DONTWAIT);
+                        int nBytes = 0;
+                        {
+                            LOCK(pnode->cs_hSocket);
+                            if (pnode->hSocket == INVALID_SOCKET)
+                                continue;
+                            nBytes = recv(pnode->hSocket, pchBuf, sizeof(pchBuf), MSG_DONTWAIT);
+                        }
                         if (nBytes > 0)
                         {
                             bool notify = false;
@@ -2286,8 +2303,7 @@ void CConnman::Stop()
 
     // Close sockets
     BOOST_FOREACH(CNode* pnode, vNodes)
-        if (pnode->hSocket != INVALID_SOCKET)
-            CloseSocket(pnode->hSocket);
+        pnode->CloseSocketDisconnect();
     BOOST_FOREACH(ListenSocket& hListenSocket, vhListenSocket)
         if (hListenSocket.socket != INVALID_SOCKET)
             if (!CloseSocket(hListenSocket.socket))
@@ -2688,9 +2704,6 @@ void CConnman::PushMessage(CNode* pnode, CSerializedNetMsg&& msg)
     size_t nBytesSent = 0;
     {
         LOCK(pnode->cs_vSend);
-        if(pnode->hSocket == INVALID_SOCKET) {
-            return;
-        }
         bool optimisticSend(pnode->vSendMsg.empty());
 
         //log total amount of bytes per command
diff --git a/src/net.h b/src/net.h
index 38f8d82ceb..e5a19e0f43 100644
--- a/src/net.h
+++ b/src/net.h
@@ -572,6 +572,7 @@ public:
     uint64_t nSendBytes;
     std::deque<std::vector<unsigned char>> vSendMsg;
     CCriticalSection cs_vSend;
+    CCriticalSection cs_hSocket;
 
     CCriticalSection cs_vProcessMsg;
     std::list<CNetMessage> vProcessMsg;
-- 
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