Add -seednode connections, and use this for -dnsseed + -proxydns

Author: sipa

src/init.cpp

@@ -180,12 +180,13 @@ bool AppInit2(int argc, char* argv[])
             "  -timeout=<n>     \t  "   + _("Specify connection timeout (in milliseconds)") + "\n" +
             "  -proxy=<ip:port> \t  "   + _("Connect through socks proxy") + "\n" +
             "  -socks=<n>       \t  "   + _("Select the version of socks proxy to use (4 or 5, 5 is default)") + "\n" +
-            "  -dns             \t  "   + _("Allow DNS lookups for addnode and connect") + "\n" +
+            "  -dns             \t  "   + _("Allow DNS lookups for -addnode, -seednode and -connect") + "\n" +
             "  -proxydns        \t  "   + _("Pass DNS requests to (SOCKS5) proxy") + "\n" +
             "  -port=<port>     \t\t  " + _("Listen for connections on <port> (default: 8333 or testnet: 18333)") + "\n" +
             "  -maxconnections=<n>\t  " + _("Maintain at most <n> connections to peers (default: 125)") + "\n" +
             "  -addnode=<ip>    \t  "   + _("Add a node to connect to and attempt to keep the connection open") + "\n" +
             "  -connect=<ip>    \t\t  " + _("Connect only to the specified node") + "\n" +
+            "  -seednode=<ip>   \t\t  " + _("Connect to a node to retrieve peer addresses, and disconnect") + "\n" +
             "  -irc             \t  "   + _("Find peers using internet relay chat (default: 0)") + "\n" +
             "  -listen          \t  "   + _("Accept connections from outside (default: 1)") + "\n" +
 #ifdef QT_GUI
@@ -536,6 +537,9 @@ bool AppInit2(int argc, char* argv[])
     fNoListen = !GetBoolArg("-listen", true);
     nSocksVersion = GetArg("-socks", 5);
 
+    BOOST_FOREACH(string strDest, mapMultiArgs["-seednode"])
+        AddOneShot(strDest);
+
     // Continue to put "/P2SH/" in the coinbase to monitor
     // BIP16 support.
     // This can be removed eventually...

src/main.cpp

@@ -2264,7 +2264,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
             }
 
             // Get recent addresses
-            if (pfrom->nVersion >= CADDR_TIME_VERSION || addrman.size() < 1000)
+            if (pfrom->fOneShot || pfrom->nVersion >= CADDR_TIME_VERSION || addrman.size() < 1000)
             {
                 pfrom->PushMessage("getaddr");
                 pfrom->fGetAddr = true;
@@ -2280,7 +2280,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
 
         // Ask the first connected node for block updates
         static int nAskedForBlocks = 0;
-        if (!pfrom->fClient &&
+        if (!pfrom->fClient && !pfrom->fOneShot &&
             (pfrom->nVersion < NOBLKS_VERSION_START ||
              pfrom->nVersion >= NOBLKS_VERSION_END) &&
              (nAskedForBlocks < 1 || vNodes.size() <= 1))
@@ -2378,6 +2378,8 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         addrman.Add(vAddr, pfrom->addr, 2 * 60 * 60);
         if (vAddr.size() < 1000)
             pfrom->fGetAddr = false;
+        if (pfrom->fOneShot)
+            pfrom->fDisconnect = true;
     }
 
 

src/net.cpp

@@ -35,7 +35,7 @@ void ThreadOpenAddedConnections2(void* parg);
 void ThreadMapPort2(void* parg);
 #endif
 void ThreadDNSAddressSeed2(void* parg);
-bool OpenNetworkConnection(const CAddress& addrConnect, const char *strDest = NULL);
+bool OpenNetworkConnection(const CAddress& addrConnect, const char *strDest = NULL, bool fOneShot = false);
 
 
 
@@ -59,6 +59,8 @@ deque<pair<int64, CInv> > vRelayExpiration;
 CCriticalSection cs_mapRelay;
 map<CInv, int64> mapAlreadyAskedFor;
 
+static deque<string> vOneShots;
+CCriticalSection cs_vOneShots;
 
 set<CNetAddr> setservAddNodeAddresses;
 CCriticalSection cs_setservAddNodeAddresses;
@@ -68,6 +70,12 @@ static int nOutbound = 0;
 static CConditionVariable condOutbound;
 
 
+void AddOneShot(string strDest)
+{
+    LOCK(cs_vOneShots);
+    vOneShots.push_back(strDest);
+}
+
 unsigned short GetListenPort()
 {
     return (unsigned short)(GetArg("-port", GetDefaultPort()));
@@ -328,7 +336,7 @@ CNode* FindNode(const CService& addr)
 
 CNode* ConnectNode(CAddress addrConnect, const char *pszDest, int64 nTimeout)
 {
-    if (pszDest != NULL) {
+    if (pszDest == NULL) {
         if ((CNetAddr)addrConnect == (CNetAddr)addrLocalHost)
             return NULL;
 
@@ -1038,8 +1046,7 @@ void ThreadDNSAddressSeed2(void* parg)
 
         for (unsigned int seed_idx = 0; seed_idx < ARRAYLEN(strDNSSeed); seed_idx++) {
             if (fProxyNameLookup) {
-                CAddress addr;
-                OpenNetworkConnection(addr, strDNSSeed[seed_idx][1]);
+                AddOneShot(strDNSSeed[seed_idx][1]);
             } else {
                 vector<CNetAddr> vaddr;
                 vector<CAddress> vAdd;
@@ -1205,6 +1212,21 @@ void ThreadOpenConnections(void* parg)
     printf("ThreadOpenConnections exiting\n");
 }
 
+void static ProcessOneShot()
+{
+    string strDest;
+    {
+        LOCK(cs_vOneShots);
+        if (vOneShots.empty())
+            return;
+        strDest = vOneShots.front();
+        vOneShots.pop_front();
+    }
+    CAddress addr;
+    if (!OpenNetworkConnection(addr, strDest.c_str(), true))
+        AddOneShot(strDest);
+}
+
 void ThreadOpenConnections2(void* parg)
 {
     printf("ThreadOpenConnections started\n");
@@ -1214,9 +1236,10 @@ void ThreadOpenConnections2(void* parg)
     {
         for (int64 nLoop = 0;; nLoop++)
         {
+            ProcessOneShot();
             BOOST_FOREACH(string strAddr, mapMultiArgs["-connect"])
             {
-                CAddress addr(CService("0.0.0.0:0"));
+                CAddress addr;
                 OpenNetworkConnection(addr, strAddr.c_str());
                 for (int i = 0; i < 10 && i < nLoop; i++)
                 {
@@ -1232,6 +1255,8 @@ void ThreadOpenConnections2(void* parg)
     int64 nStart = GetTime();
     loop
     {
+        ProcessOneShot();
+
         vnThreadsRunning[THREAD_OPENCONNECTIONS]--;
         Sleep(500);
         vnThreadsRunning[THREAD_OPENCONNECTIONS]++;
@@ -1403,7 +1428,7 @@ void ThreadOpenAddedConnections2(void* parg)
     }
 }
 
-bool OpenNetworkConnection(const CAddress& addrConnect, const char *strDest)
+bool OpenNetworkConnection(const CAddress& addrConnect, const char *strDest, bool fOneShot)
 {
     //
     // Initiate outbound network connection
@@ -1426,6 +1451,8 @@ bool OpenNetworkConnection(const CAddress& addrConnect, const char *strDest)
     if (!pnode)
         return false;
     pnode->fNetworkNode = true;
+    if (fOneShot)
+        pnode->fOneShot = true;
 
     return true;
 }

src/net.h

@@ -30,6 +30,7 @@ extern int nBestHeight;
 inline unsigned int ReceiveBufferSize() { return 1000*GetArg("-maxreceivebuffer", 10*1000); }
 inline unsigned int SendBufferSize() { return 1000*GetArg("-maxsendbuffer", 10*1000); }
 
+void AddOneShot(std::string strDest);
 bool RecvLine(SOCKET hSocket, std::string& strLine);
 bool GetMyExternalIP(CNetAddr& ipRet);
 void AddressCurrentlyConnected(const CService& addr);
@@ -122,6 +123,7 @@ class CNode
     std::string addrName;
     int nVersion;
     std::string strSubVer;
+    bool fOneShot;
     bool fClient;
     bool fInbound;
     bool fNetworkNode;
@@ -171,6 +173,7 @@ class CNode
         addrName = addrNameIn == "" ? addr.ToStringIPPort() : addrNameIn;
         nVersion = 0;
         strSubVer = "";
+        fOneShot = false;
         fClient = false; // set by version message
         fInbound = fInboundIn;
         fNetworkNode = false;