hack in support for dns querying non standard ports (nonstd. host alias)

return rec 1 = {IP}, rec 2 = {CRC16(IP), port}, ...

db.cpp

@@ -166,7 +166,7 @@ void CAddrDb::Add_(const CAddress &addr, bool force) {
   nDirty++;
 }
 
-void CAddrDb::GetIPs_(set<CNetAddr>& ips, int max, const bool* nets) {
+void CAddrDb::GetIPs_(set<CService>& ips, int max, const bool* nets) {
   if (goodId.size() == 0) {
     int id = -1;
     if (ourId.size() == 0) {

db.h

@@ -102,7 +102,7 @@ public:
   }
   
   bool IsGood() const {
-    if (ip.GetPort() != GetDefaultPort()) return false;
+    /*if (ip.GetPort() != GetDefaultPort()) return false;*/ // [MF] we now permit non std ports
     if (!(services & NODE_NETWORK)) return false;
     if (!ip.IsRoutable()) return false;
     if (clientVersion && clientVersion < REQUIRE_VERSION) return false;
@@ -220,7 +220,7 @@ protected:
   void Bad_(const CService &ip, int ban);  // mark an IP as bad (and optionally ban it) (must have been returned by Get_)
   void Skipped_(const CService &ip);       // mark an IP as skipped (must have been returned by Get_)
   int Lookup_(const CService &ip);         // look up id of an IP
-  void GetIPs_(std::set<CNetAddr>& ips, int max, const bool *nets); // get a random set of IPs (shared lock only)
+  void GetIPs_(std::set<CService>& ips, int max, const bool *nets); // get a random set of IPs (shared lock only)
 
 public:
   std::map<CService, time_t> banned; // nodes that are banned, with their unban time (a)
@@ -352,7 +352,7 @@ public:
       }
     }
   }
-  void GetIPs(std::set<CNetAddr>& ips, int max, const bool *nets) {
+  void GetIPs(std::set<CService>& ips, int max, const bool *nets) {
     SHARED_CRITICAL_BLOCK(cs)
       GetIPs_(ips, max, nets);
   }

dns.c

@@ -269,6 +269,8 @@ ssize_t static dnshandle(dns_opt_t *opt, const unsigned char *inbuf, size_t insi
   if (ret == -2) { error = 5; goto error; }
   int namel = strlen(name), hostl = strlen(opt->host);
   if (strcasecmp(name, opt->host) && (namel<hostl+2 || name[namel-hostl-1]!='.' || strcasecmp(name+namel-hostl,opt->host))) { error = 5; goto error; }
+  static char nonStdStr[] = "nonstd.";
+  int nonStd = (strncmp(name,nonStdStr,strlen(nonStdStr)) == 0);
   if (inend - inpos < 4) { error = 1; goto error; }
   // copy question to output
   memcpy(outbuf+12, inbuf+12, inpos+4 - (inbuf+12));
@@ -322,7 +324,12 @@ ssize_t static dnshandle(dns_opt_t *opt, const unsigned char *inbuf, size_t insi
   // A/AAAA records
   if ((typ == TYPE_A || typ == TYPE_AAAA || typ == QTYPE_ANY) && (cls == CLASS_IN || cls == QCLASS_ANY)) {
     addr_t addr[32];
-    int naddr = opt->cb((void*)opt, addr, 32, typ == TYPE_A || typ == QTYPE_ANY, typ == TYPE_AAAA || typ == QTYPE_ANY);
+    int naddr;
+    if( !nonStd) {
+      naddr = opt->cb((void*)opt, addr, 32, typ == TYPE_A || typ == QTYPE_ANY, typ == TYPE_AAAA || typ == QTYPE_ANY);
+    } else {
+      naddr = opt->cbNonStd((void*)opt, addr, 32, typ == TYPE_A || typ == QTYPE_ANY, typ == TYPE_AAAA || typ == QTYPE_ANY);
+    }
     int n = 0;
     while (n < naddr) {
       int ret = 1;

dns.h

@@ -5,6 +5,7 @@
 
 typedef struct {
     int v;
+    unsigned short port;
     union {
        unsigned char v4[4];
        unsigned char v6[16];
@@ -19,6 +20,7 @@ typedef struct {
   const char *ns;
   const char *mbox;
   int (*cb)(void *opt, addr_t *addr, int max, int ipv4, int ipv6);
+  int (*cbNonStd)(void *opt, addr_t *addr, int max, int ipv4, int ipv6);
   // stats
   uint64_t nRequests;
 } dns_opt_t;

main.cpp

@@ -160,13 +160,16 @@ extern "C" void* ThreadCrawler(void* data) {
 }
 
 extern "C" int GetIPList(void *thread, addr_t *addr, int max, int ipv4, int ipv6);
+extern "C" int GetIPListNonStd(void *thread, addr_t *addr, int max, int ipv4, int ipv6);
 
 class CDnsThread {
 public:
   dns_opt_t dns_opt; // must be first
   const int id;
   vector<addr_t> cache;
+  vector<addr_t> cacheNonStd; // [MF] non std port
   int nIPv4, nIPv6;
+  int nonStdIPv4, nonStdIPv6;
   time_t cacheTime;
   unsigned int cacheHits;
   uint64_t dbQueries;
@@ -180,29 +183,43 @@ public:
     time_t now = time(NULL);
     cacheHits++;
     if (force || cacheHits > (cache.size()*cache.size()/400) || (cacheHits*cacheHits > cache.size() / 20 && (now - cacheTime > 5))) {
-      set<CNetAddr> ips;
+      set<CService> ips;
       db.GetIPs(ips, 1000, nets);
       dbQueries++;
       cache.clear();
-      nIPv4 = 0;
-      nIPv6 = 0;
+      cacheNonStd.clear();
+      nIPv4 = nonStdIPv4 = 0;
+      nIPv6 = nonStdIPv6 = 0;
       cache.reserve(ips.size());
-      for (set<CNetAddr>::iterator it = ips.begin(); it != ips.end(); it++) {
+      cacheNonStd.reserve(ips.size());
+      for (set<CService>::iterator it = ips.begin(); it != ips.end(); it++) {
         struct in_addr addr;
         struct in6_addr addr6;
         if ((*it).GetInAddr(&addr)) {
           addr_t a;
           a.v = 4;
+          a.port = (*it).GetPort();
           memcpy(&a.data.v4, &addr, 4);
-          cache.push_back(a);
-          nIPv4++;
+          if( a.port == GetDefaultPort() ) {
+            cache.push_back(a);
+            nIPv4++;
+          } else {
+            cacheNonStd.push_back(a);
+            nonStdIPv4++;
+          }
 #ifdef USE_IPV6
         } else if ((*it).GetIn6Addr(&addr6)) {
           addr_t a;
           a.v = 6;
+          a.port = (*it).GetPort();
           memcpy(&a.data.v6, &addr6, 16);
-          cache.push_back(a);
-          nIPv6++;
+          if( a.port == GetDefaultPort() ) {
+            cache.push_back(a);
+            nIPv6++;
+          } else {
+            cacheNonStd.push_back(a);
+            nonStdIPv6++;
+          }
 #endif
         }
       }
@@ -218,6 +235,7 @@ public:
     dns_opt.datattl = 60;
     dns_opt.nsttl = 40000;
     dns_opt.cb = GetIPList;
+    dns_opt.cbNonStd = GetIPListNonStd;
     dns_opt.port = opts->nPort;
     dns_opt.nRequests = 0;
     cache.clear();
@@ -235,6 +253,18 @@ public:
   }
 };
 
+unsigned short crc16(unsigned char* data_p, unsigned char length){
+    unsigned char x;
+    unsigned short crc = 0xFFFF;
+
+    while (length--){
+        x = crc >> 8 ^ *data_p++;
+        x ^= x>>4;
+        crc = (crc << 8) ^ ((unsigned short)(x << 12)) ^ ((unsigned short)(x <<5)) ^ ((unsigned short)x);
+    }
+    return crc;
+}
+
 extern "C" int GetIPList(void *data, addr_t* addr, int max, int ipv4, int ipv6) {
   CDnsThread *thread = (CDnsThread*)data;
   thread->cacheHit();
@@ -264,6 +294,48 @@ extern "C" int GetIPList(void *data, addr_t* addr, int max, int ipv4, int ipv6)
   return max;
 }
 
+extern "C" int GetIPListNonStd(void *data, addr_t* addr, int max, int ipv4, int ipv6) {
+  CDnsThread *thread = (CDnsThread*)data;
+  thread->cacheHit();
+  unsigned int size = thread->cacheNonStd.size();
+  unsigned int maxmax = (ipv4 ? thread->nonStdIPv4 : 0) + (ipv6 ? thread->nonStdIPv6 : 0);
+  
+  if (max > 2 * size)
+    max = 2 * size;
+  if (max > 2 * maxmax)
+    max = 2 * maxmax;
+  max -= max % 2;
+  int i=0;
+  while (i+1<max) {
+    int j = i/2 + (rand() % (size - i/2));
+    unsigned short crcAddr = 0;
+    do {
+        bool ok = (ipv4 && thread->cacheNonStd[j].v == 4) || 
+                  (ipv6 && thread->cacheNonStd[j].v == 6);
+        if (ok) break;
+        j++;
+        if (j==size)
+            j=i/2;
+    } while(1);
+    addr[i] = thread->cacheNonStd[j];
+    thread->cacheNonStd[j] = thread->cacheNonStd[i/2];
+    thread->cacheNonStd[i/2] = addr[i];
+    
+    if( addr[i].v == 4 ) {
+      crcAddr = crc16(addr[i].data.v4,4);
+    } else {
+      crcAddr = crc16(addr[i].data.v6,16);
+    }
+    addr[i+1].v = 4;
+    addr[i+1].data.v4[0] = crcAddr >> 8;
+    addr[i+1].data.v4[1] = crcAddr & 0xff;
+    addr[i+1].data.v4[2] = addr[i].port >> 8;
+    addr[i+1].data.v4[3] = addr[i].port & 0xff;
+    i+=2;
+  }
+  return max;
+}
+
 vector<CDnsThread*> dnsThread;
 
 extern "C" void* ThreadDNS(void* arg) {