1 files changed, 186 insertions, 0 deletions
diff --git a/dnsdist-lua-network.cc b/dnsdist-lua-network.cc
new file mode 100644
index 0000000..6892888
--- /dev/null
+++ b/dnsdist-lua-network.cc
@@ -0,0 +1,186 @@
+/*
+ * 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 <sys/socket.h>
+#include <sys/un.h>
+
+#include "dnsdist-lua-network.hh"
+#include "dolog.hh"
+#include "threadname.hh"
+
+namespace dnsdist
+{
+NetworkListener::NetworkListener() :
+  d_mplexer(std::unique_ptr<FDMultiplexer>(FDMultiplexer::getMultiplexerSilent(10)))
+{
+}
+
+void NetworkListener::readCB(int desc, FDMultiplexer::funcparam_t& param)
+{
+  auto cbData = boost::any_cast<std::shared_ptr<NetworkListener::CBData>>(param);
+  std::string packet;
+
+#ifdef MSG_TRUNC
+  /* first we peek to avoid allocating a very large buffer. "MSG_TRUNC [...] return the real length of the datagram, even when it was longer than the passed buffer" */
+  auto peeked = recvfrom(desc, nullptr, 0, MSG_PEEK | MSG_TRUNC, nullptr, 0);
+  if (peeked > 0) {
+    packet.resize(static_cast<size_t>(peeked));
+  }
+#endif
+  if (packet.size() == 0) {
+    packet.resize(65535);
+  }
+
+  struct sockaddr_un from;
+  memset(&from, 0, sizeof(from));
+
+  socklen_t fromLen = sizeof(from);
+  auto got = recvfrom(desc, &packet.at(0), packet.size(), 0, reinterpret_cast<sockaddr*>(&from), &fromLen);
+  if (got > 0) {
+    packet.resize(static_cast<size_t>(got));
+    std::string fromAddr;
+    if (fromLen <= sizeof(from)) {
+      fromAddr = std::string(from.sun_path, strlen(from.sun_path));
+    }
+    try {
+      cbData->d_cb(cbData->d_endpoint, std::move(packet), fromAddr);
+    }
+    catch (const std::exception& e) {
+      vinfolog("Exception in the read callback of a NetworkListener: %s", e.what());
+    }
+    catch (...) {
+      vinfolog("Exception in the read callback of a NetworkListener");
+    }
+  }
+}
+
+bool NetworkListener::addUnixListeningEndpoint(const std::string& path, NetworkListener::EndpointID id, NetworkListener::NetworkDatagramCB cb)
+{
+  if (d_running == true) {
+    throw std::runtime_error("NetworkListener should not be altered at runtime");
+  }
+
+  struct sockaddr_un sun;
+  if (makeUNsockaddr(path, &sun) != 0) {
+    throw std::runtime_error("Invalid Unix socket path '" + path + "'");
+  }
+
+  bool abstractPath = path.at(0) == '\0';
+  if (!abstractPath) {
+    int err = unlink(path.c_str());
+    if (err != 0) {
+      err = errno;
+      if (err != ENOENT) {
+        vinfolog("Error removing Unix socket to path '%s': %s", path, stringerror(err));
+      }
+    }
+  }
+
+  Socket sock(sun.sun_family, SOCK_DGRAM, 0);
+  socklen_t sunLength = sizeof(sun);
+  if (abstractPath) {
+    /* abstract paths can contain null bytes so we need to set the actual size */
+    sunLength = sizeof(sa_family_t) + path.size();
+  }
+
+  if (bind(sock.getHandle(), reinterpret_cast<const struct sockaddr*>(&sun), sunLength) != 0) {
+    std::string sanitizedPath(path);
+    if (abstractPath) {
+      sanitizedPath[0] = '@';
+    }
+    throw std::runtime_error("Error binding Unix socket to path '" + sanitizedPath + "': " + stringerror());
+  }
+
+  sock.setNonBlocking();
+
+  auto cbData = std::make_shared<CBData>();
+  cbData->d_endpoint = id;
+  cbData->d_cb = cb;
+  d_mplexer->addReadFD(sock.getHandle(), readCB, cbData);
+
+  d_sockets.insert({path, std::move(sock)});
+  return true;
+}
+
+void NetworkListener::runOnce(struct timeval& now, uint32_t timeout)
+{
+  d_running = true;
+  if (d_sockets.empty()) {
+    throw runtime_error("NetworkListener started with no sockets");
+  }
+
+  d_mplexer->run(&now, timeout);
+}
+
+void NetworkListener::mainThread()
+{
+  setThreadName("dnsdist/lua-net");
+  struct timeval now;
+
+  while (true) {
+    runOnce(now, -1);
+  }
+}
+
+void NetworkListener::start()
+{
+  std::thread main = std::thread([this] {
+    mainThread();
+  });
+  main.detach();
+}
+
+NetworkEndpoint::NetworkEndpoint(const std::string& path) :
+  d_socket(AF_UNIX, SOCK_DGRAM, 0)
+{
+  struct sockaddr_un sun;
+  if (makeUNsockaddr(path, &sun) != 0) {
+    throw std::runtime_error("Invalid Unix socket path '" + path + "'");
+  }
+
+  socklen_t sunLength = sizeof(sun);
+  bool abstractPath = path.at(0) == '\0';
+
+  if (abstractPath) {
+    /* abstract paths can contain null bytes so we need to set the actual size */
+    sunLength = sizeof(sa_family_t) + path.size();
+  }
+  if (connect(d_socket.getHandle(), reinterpret_cast<const struct sockaddr*>(&sun), sunLength) != 0) {
+    std::string sanitizedPath(path);
+    if (abstractPath) {
+      sanitizedPath[0] = '@';
+    }
+    throw std::runtime_error("Error connecting Unix socket to path '" + sanitizedPath + "': " + stringerror());
+  }
+
+  d_socket.setNonBlocking();
+}
+
+bool NetworkEndpoint::send(const std::string_view& payload) const
+{
+  auto sent = ::send(d_socket.getHandle(), payload.data(), payload.size(), 0);
+  if (sent <= 0) {
+    return false;
+  }
+
+  return static_cast<size_t>(sent) == payload.size();
+}
+}