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, 14 insertions, 24 deletions

diff --git a/src/irc.cpp b/src/irc.cpp
index 5adaf11658..4e39889245 100644
--- a/src/irc.cpp
+++ b/src/irc.cpp
@@ -41,7 +41,7 @@ bool DecodeAddress(string str, CAddress& addr)
         return false;
     memcpy(&tmp, &vch[0], sizeof(tmp));
 
-    addr = CAddress(tmp.ip, tmp.port, NODE_NETWORK);
+    addr = CAddress(tmp.ip, ntohs(tmp.port), NODE_NETWORK);
     return true;
 }
 
@@ -215,25 +215,15 @@ bool GetIPFromIRC(SOCKET hSocket, string strMyName, unsigned int& ipRet)
         return false;
     string strHost = str.substr(str.rfind("@")+1);
 
-    unsigned int a=0, b=0, c=0, d=0;
-    if (sscanf(strHost.c_str(), "%u.%u.%u.%u", &a, &b, &c, &d) == 4 &&
-        inet_addr(strHost.c_str()) != INADDR_NONE)
-    {
-        printf("GetIPFromIRC() userhost is IP %s\n", strHost.c_str());
-        ipRet = CAddress(strHost).ip;
-    }
-    else
-    {
-        // Hybrid IRC used by lfnet always returns IP when you userhost yourself,
-        // but in case another IRC is ever used this should work.
-        printf("GetIPFromIRC() got userhost %s\n", strHost.c_str());
-        if (fUseProxy)
-            return false;
-        struct hostent* phostent = gethostbyname(strHost.c_str());
-        if (!phostent || !phostent->h_addr_list || !phostent->h_addr_list[0])
-            return false;
-        ipRet = *(u_long*)phostent->h_addr_list[0];
-    }
+    // Hybrid IRC used by lfnet always returns IP when you userhost yourself,
+    // but in case another IRC is ever used this should work.
+    printf("GetIPFromIRC() got userhost %s\n", strHost.c_str());
+    if (fUseProxy)
+        return false;
+    CAddress addr(strHost, 0, true);
+    if (!addr.IsValid())
+        return false;
+    ipRet = addr.ip;
 
     return true;
 }
@@ -276,9 +266,9 @@ void ThreadIRCSeed2(void* parg)
         if (!fTOR)
         {
             //struct hostent* phostent = gethostbyname("chat.freenode.net");
-            struct hostent* phostent = gethostbyname("irc.lfnet.org");
-            if (phostent && phostent->h_addr_list && phostent->h_addr_list[0])
-                addrConnect = CAddress(*(u_long*)phostent->h_addr_list[0], htons(6667));
+            CAddress addrIRC("irc.lfnet.org:6667", 0, true);
+            if (addrIRC.IsValid())
+                addrConnect = addrIRC;
         }
 
         SOCKET hSocket;
@@ -390,7 +380,7 @@ void ThreadIRCSeed2(void* parg)
                 {
                     addr.nTime = GetAdjustedTime();
                     if (AddAddress(addr, 51 * 60))
-                        printf("IRC got new address\n");
+                        printf("IRC got new address: %s\n", addr.ToString().c_str());
                     nGotIRCAddresses++;
                 }
                 else