net: require lookup functions to specify all arguments

To make it clear where DNS resolves are happening

src/net.cpp

@@ -1443,7 +1443,7 @@ void ThreadDNSAddressSeed()
         } else {
             vector<CNetAddr> vIPs;
             vector<CAddress> vAdd;
-            if (LookupHost(seed.host.c_str(), vIPs))
+            if (LookupHost(seed.host.c_str(), vIPs, 0, true))
             {
                 BOOST_FOREACH(const CNetAddr& ip, vIPs)
                 {
@@ -1884,7 +1884,7 @@ void static Discover(boost::thread_group& threadGroup)
     if (gethostname(pszHostName, sizeof(pszHostName)) != SOCKET_ERROR)
     {
         vector<CNetAddr> vaddr;
-        if (LookupHost(pszHostName, vaddr))
+        if (LookupHost(pszHostName, vaddr, 0, true))
         {
             BOOST_FOREACH (const CNetAddr &addr, vaddr)
             {

src/netbase.h

@@ -206,9 +206,9 @@ bool GetProxy(enum Network net, proxyType &proxyInfoOut);
 bool IsProxy(const CNetAddr &addr);
 bool SetNameProxy(const proxyType &addrProxy);
 bool HaveNameProxy();
-bool LookupHost(const char *pszName, std::vector<CNetAddr>& vIP, unsigned int nMaxSolutions = 0, bool fAllowLookup = true);
+bool LookupHost(const char *pszName, std::vector<CNetAddr>& vIP, unsigned int nMaxSolutions, bool fAllowLookup);
-bool Lookup(const char *pszName, CService& addr, int portDefault = 0, bool fAllowLookup = true);
+bool Lookup(const char *pszName, CService& addr, int portDefault, bool fAllowLookup);
-bool Lookup(const char *pszName, std::vector<CService>& vAddr, int portDefault = 0, bool fAllowLookup = true, unsigned int nMaxSolutions = 0);
+bool Lookup(const char *pszName, std::vector<CService>& vAddr, int portDefault, bool fAllowLookup, unsigned int nMaxSolutions);
 bool LookupNumeric(const char *pszName, CService& addr, int portDefault = 0);
 bool ConnectSocket(const CService &addr, SOCKET& hSocketRet, int nTimeout, bool *outProxyConnectionFailed = 0);
 bool ConnectSocketByName(CService &addr, SOCKET& hSocketRet, const char *pszDest, int portDefault, int nTimeout, bool *outProxyConnectionFailed = 0);