Support for name lookups in -connect and -addnode

* A new option -dns is introduced that enables name lookups in
  -connect and -addnode, which is not enabled by default,
  as it may be considered a security issue.
* A Lookup function is added that supports retrieving one or
  more addresses based on a host name
* CAddress constructors (optionally) support name lookups.
* The different places in the source code that did name lookups
  are refactored to use NameLookup or CAddress instead (dns seeding,
  irc server lookup, getexternalip, ...).
* Removed ToStringLog() from CAddress, and switched to ToString(),
  since it was empty.

1 files changed, 22 insertions, 40 deletions

diff --git a/src/net.h b/src/net.h
index b3bd74da47..ea12b983e4 100644
--- a/src/net.h
+++ b/src/net.h
@@ -12,7 +12,7 @@ extern int nBestHeight;
 
 
 
-inline unsigned short GetDefaultPort() { return fTestNet ? htons(18333) : htons(8333); }
+inline unsigned short GetDefaultPort() { return fTestNet ? 18333 : 8333; }
 static const unsigned int PUBLISH_HOPS = 5;
 enum
 {
@@ -23,6 +23,8 @@ enum
 
 
 bool ConnectSocket(const CAddress& addrConnect, SOCKET& hSocketRet);
+bool Lookup(const char *pszName, vector<CAddress>& vaddr, int nServices, int nMaxSolutions, bool fAllowLookup = false, int portDefault = 0, bool fAllowPort = false);
+bool Lookup(const char *pszName, CAddress& addr, int nServices, bool fAllowLookup = false, int portDefault = 0, bool fAllowPort = false);
 bool GetMyExternalIP(unsigned int& ipRet);
 bool AddAddress(CAddress addr, int64 nTimePenalty=0);
 void AddressCurrentlyConnected(const CAddress& addr);
@@ -156,7 +158,7 @@ public:
     {
         Init();
         ip = ipIn;
-        port = (portIn == 0 ? GetDefaultPort() : portIn);
+        port = htons(portIn == 0 ? GetDefaultPort() : portIn);
         nServices = nServicesIn;
     }
 
@@ -168,54 +170,38 @@ public:
         nServices = nServicesIn;
     }
 
-    explicit CAddress(const char* pszIn, uint64 nServicesIn=NODE_NETWORK)
+    explicit CAddress(const char* pszIn, int portIn, bool fNameLookup = false, uint64 nServicesIn=NODE_NETWORK)
     {
         Init();
-        SetAddress(pszIn);
-        nServices = nServicesIn;
+        Lookup(pszIn, *this, nServicesIn, fNameLookup, portIn);
     }
 
-    explicit CAddress(string strIn, uint64 nServicesIn=NODE_NETWORK)
+    explicit CAddress(const char* pszIn, bool fNameLookup = false, uint64 nServicesIn=NODE_NETWORK)
     {
         Init();
-        SetAddress(strIn.c_str());
-        nServices = nServicesIn;
+        Lookup(pszIn, *this, nServicesIn, fNameLookup, 0, true);
     }
 
-    void Init()
+    explicit CAddress(string strIn, int portIn, bool fNameLookup = false, uint64 nServicesIn=NODE_NETWORK)
     {
-        nServices = NODE_NETWORK;
-        memcpy(pchReserved, pchIPv4, sizeof(pchReserved));
-        ip = INADDR_NONE;
-        port = GetDefaultPort();
-        nTime = 100000000;
-        nLastTry = 0;
+        Init();
+        Lookup(strIn.c_str(), *this, nServicesIn, fNameLookup, portIn);
     }
 
-    bool SetAddress(const char* pszIn)
+    explicit CAddress(string strIn, bool fNameLookup = false, uint64 nServicesIn=NODE_NETWORK)
     {
-        ip = INADDR_NONE;
-        port = GetDefaultPort();
-        char psz[100];
-        strlcpy(psz, pszIn, sizeof(psz));
-        unsigned int a=0, b=0, c=0, d=0, e=0;
-        if (sscanf(psz, "%u.%u.%u.%u:%u", &a, &b, &c, &d, &e) < 4)
-            return false;
-        char* pszPort = strchr(psz, ':');
-        if (pszPort)
-        {
-            *pszPort++ = '\0';
-            port = htons(atoi(pszPort));
-            if (atoi(pszPort) < 0 || atoi(pszPort) > USHRT_MAX)
-                port = htons(USHRT_MAX);
-        }
-        ip = inet_addr(psz);
-        return IsValid();
+        Init();
+        Lookup(strIn.c_str(), *this, nServicesIn, fNameLookup, 0, true);
     }
 
-    bool SetAddress(string strIn)
+    void Init()
     {
-        return SetAddress(strIn.c_str());
+        nServices = NODE_NETWORK;
+        memcpy(pchReserved, pchIPv4, sizeof(pchReserved));
+        ip = INADDR_NONE;
+        port = htons(GetDefaultPort());
+        nTime = 100000000;
+        nLastTry = 0;
     }
 
     IMPLEMENT_SERIALIZE
@@ -330,11 +316,6 @@ public:
         return strprintf("%u", ntohs(port));
     }
 
-    string ToStringLog() const
-    {
-        return "";
-    }
-
     string ToString() const
     {
         return strprintf("%u.%u.%u.%u:%u", GetByte(3), GetByte(2), GetByte(1), GetByte(0), ntohs(port));
@@ -460,6 +441,7 @@ public:
 
 
 extern bool fClient;
+extern bool fAllowDNS;
 extern uint64 nLocalServices;
 extern CAddress addrLocalHost;
 extern CNode* pnodeLocalHost;