1 files changed, 108 insertions, 0 deletions
diff --git a/ednssubnet.cc b/ednssubnet.cc
new file mode 100644
index 0000000..cf78ecf
--- /dev/null
+++ b/ednssubnet.cc
@@ -0,0 +1,108 @@
+/*
+ * This file is part of PowerDNS or dnsdist.
+ * Copyright -- PowerDNS.COM B.V. and its contributors
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * In addition, for the avoidance of any doubt, permission is granted to
+ * link this program with OpenSSL and to (re)distribute the binaries
+ * produced as the result of such linking.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+#include "ednssubnet.hh"
+#include "dns.hh"
+
+namespace {
+        struct EDNSSubnetOptsWire
+        {
+                uint16_t family;
+                uint8_t sourceMask;
+                uint8_t scopeMask;
+        } GCCPACKATTRIBUTE;  // BRRRRR
+
+}
+
+bool getEDNSSubnetOptsFromString(const string& options, EDNSSubnetOpts* eso)
+{
+  //cerr<<"options.size:"<<options.size()<<endl;
+  return getEDNSSubnetOptsFromString(options.c_str(), options.length(), eso);
+}
+bool getEDNSSubnetOptsFromString(const char* options, unsigned int len, EDNSSubnetOpts* eso)
+{
+  EDNSSubnetOptsWire esow;
+  static_assert (sizeof(esow) == 4, "sizeof(EDNSSubnetOptsWire) must be 4 bytes");
+  if(len < sizeof(esow))
+    return false;
+  memcpy(&esow, options, sizeof(esow));
+  esow.family = ntohs(esow.family);
+  //cerr<<"Family when parsing from string: "<<esow.family<<endl;
+  ComboAddress address;
+  unsigned int octetsin = esow.sourceMask > 0 ? (((esow.sourceMask - 1)>> 3)+1) : 0;
+  //cerr<<"octetsin:"<<octetsin<<endl;
+  if(esow.family == 1) {
+    if(len != sizeof(esow)+octetsin)
+      return false;
+    if(octetsin > sizeof(address.sin4.sin_addr.s_addr))
+      return false;
+    address.reset();
+    address.sin4.sin_family = AF_INET;
+    if(octetsin > 0)
+      memcpy(&address.sin4.sin_addr.s_addr, options+sizeof(esow), octetsin);
+  } else if(esow.family == 2) {
+    if(len != sizeof(esow)+octetsin)
+      return false;
+    if(octetsin > sizeof(address.sin6.sin6_addr.s6_addr))
+      return false;
+
+    address.reset();
+    address.sin4.sin_family = AF_INET6;
+    if(octetsin > 0)
+      memcpy(&address.sin6.sin6_addr.s6_addr, options+sizeof(esow), octetsin);
+  }
+  else
+    return false;
+  //cerr<<"Source address: "<<address.toString()<<", mask: "<<(int)esow.sourceMask<<endl;
+  eso->source = Netmask(address, esow.sourceMask);
+  /* 'address' has more bits set (potentially) than scopeMask. This leads to odd looking netmasks that promise
+     more precision than they have. For this reason we truncate the address to scopeMask bits */
+  
+  address.truncate(esow.scopeMask); // truncate will not throw for odd scopeMasks
+  eso->scope = Netmask(address, esow.scopeMask);
+
+  return true;
+}
+
+string makeEDNSSubnetOptsString(const EDNSSubnetOpts& eso)
+{
+  string ret;
+  EDNSSubnetOptsWire esow;
+  uint16_t family = htons(eso.source.getNetwork().sin4.sin_family == AF_INET ? 1 : 2);
+  esow.family = family;
+  esow.sourceMask = eso.source.getBits();
+  esow.scopeMask = eso.scope.getBits();
+  ret.assign((const char*)&esow, sizeof(esow));
+  int octetsout = ((esow.sourceMask - 1)>> 3)+1;
+
+  ComboAddress src=eso.source.getNetwork();
+  src.truncate(esow.sourceMask);
+
+  if(family == htons(1)) 
+    ret.append((const char*) &src.sin4.sin_addr.s_addr, octetsout);
+  else
+    ret.append((const char*) &src.sin6.sin6_addr.s6_addr, octetsout);
+  return ret;
+}
+