1 files changed, 111 insertions, 0 deletions
diff --git a/dnsdist-proxy-protocol.cc b/dnsdist-proxy-protocol.cc
new file mode 100644
index 0000000..aefcafb
--- /dev/null
+++ b/dnsdist-proxy-protocol.cc
@@ -0,0 +1,111 @@
+/*
+ * 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.
+ */
+
+#include "dnsdist-proxy-protocol.hh"
+#include "dolog.hh"
+
+NetmaskGroup g_proxyProtocolACL;
+size_t g_proxyProtocolMaximumSize = 512;
+bool g_applyACLToProxiedClients = false;
+
+std::string getProxyProtocolPayload(const DNSQuestion& dq)
+{
+  return makeProxyHeader(dq.overTCP(), dq.ids.origRemote, dq.ids.origDest, dq.proxyProtocolValues ? *dq.proxyProtocolValues : std::vector<ProxyProtocolValue>());
+}
+
+bool addProxyProtocol(DNSQuestion& dq, const std::string& payload)
+{
+  if (!dq.hasRoomFor(payload.size())) {
+    return false;
+  }
+
+  return addProxyProtocol(dq.getMutableData(), payload);
+}
+
+bool addProxyProtocol(DNSQuestion& dq, size_t* payloadSize)
+{
+  auto payload = getProxyProtocolPayload(dq);
+  if (payloadSize != nullptr) {
+    *payloadSize = payload.size();
+  }
+
+  return addProxyProtocol(dq, payload);
+}
+
+bool addProxyProtocol(PacketBuffer& buffer, const std::string& payload)
+{
+  auto previousSize = buffer.size();
+  if (payload.size() > (std::numeric_limits<size_t>::max() - previousSize)) {
+    return false;
+  }
+
+  buffer.insert(buffer.begin(), payload.begin(), payload.end());
+
+  return true;
+}
+
+bool addProxyProtocol(PacketBuffer& buffer, bool tcp, const ComboAddress& source, const ComboAddress& destination, const std::vector<ProxyProtocolValue>& values)
+{
+  auto payload = makeProxyHeader(tcp, source, destination, values);
+  return addProxyProtocol(buffer, payload);
+}
+
+bool expectProxyProtocolFrom(const ComboAddress& remote)
+{
+  return g_proxyProtocolACL.match(remote);
+}
+
+bool handleProxyProtocol(const ComboAddress& remote, bool isTCP, const NetmaskGroup& acl, PacketBuffer& query, ComboAddress& realRemote, ComboAddress& realDestination, std::vector<ProxyProtocolValue>& values)
+{
+  bool tcp;
+  bool proxyProto;
+
+  ssize_t used = parseProxyHeader(query, proxyProto, realRemote, realDestination, tcp, values);
+  if (used <= 0) {
+    ++g_stats.proxyProtocolInvalid;
+    vinfolog("Ignoring invalid proxy protocol (%d, %d) query over %s from %s", query.size(), used, (isTCP ? "TCP" : "UDP"), remote.toStringWithPort());
+    return false;
+  }
+  else if (static_cast<size_t>(used) > g_proxyProtocolMaximumSize) {
+    vinfolog("Proxy protocol header in %s packet from %s is larger than proxy-protocol-maximum-size (%d), dropping", (isTCP ? "TCP" : "UDP"), remote.toStringWithPort(), used);
+    ++g_stats.proxyProtocolInvalid;
+    return false;
+  }
+
+  query.erase(query.begin(), query.begin() + used);
+
+  /* on TCP we have not read the actual query yet */
+  if (!isTCP && query.size() < sizeof(struct dnsheader)) {
+    ++g_stats.nonCompliantQueries;
+    return false;
+  }
+
+  if (proxyProto && g_applyACLToProxiedClients) {
+    if (!acl.match(realRemote)) {
+      vinfolog("Query from %s dropped because of ACL", realRemote.toStringWithPort());
+      ++g_stats.aclDrops;
+      return false;
+    }
+  }
+
+  return true;
+}