tools: NDN hub discovery server & client
refs: #1295, #1296
Change-Id: I2fb5a0a8d6435e39aca080cb51b683820dbd959e
diff --git a/tools/ndn-autoconfig.cpp b/tools/ndn-autoconfig.cpp
new file mode 100644
index 0000000..a92fad3
--- /dev/null
+++ b/tools/ndn-autoconfig.cpp
@@ -0,0 +1,270 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (C) 2014 Named Data Networking Project
+ * See COPYING for copyright and distribution information.
+ */
+#include <ndn-cpp-dev/face.hpp>
+#include <ndn-cpp-dev/management/nfd-controller.hpp>
+#include <ndn-cpp-dev/management/nfd-face-management-options.hpp>
+#include <ndn-cpp-dev/security/key-chain.hpp>
+
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <arpa/nameser.h>
+#include <resolv.h>
+
+#ifdef __APPLE__
+#include <arpa/nameser_compat.h>
+#endif
+
+class NdnAutoconfig : public ndn::nfd::Controller
+{
+public:
+ union QueryAnswer
+ {
+ HEADER header;
+ uint8_t buf[NS_PACKETSZ];
+ };
+
+ struct Error : public std::runtime_error
+ {
+ Error(const std::string& what) : std::runtime_error(what)
+ {
+ }
+ };
+
+ explicit
+ NdnAutoconfig(ndn::Face& face)
+ : ndn::nfd::Controller(face)
+ {
+ }
+
+ // Start to look for a hub (NDN hub discovery first stage)
+ void
+ discoverHubStage1()
+ {
+ ndn::Interest interest(ndn::Name("/localhop/ndn-autoconf/hub"));
+ interest.setInterestLifetime(4000); // 4 seconds
+ interest.setMustBeFresh(true);
+
+ std::cerr << "Stage 1: Trying muticast discovery..." << std::endl;
+ m_face.expressInterest(interest,
+ ndn::bind(&NdnAutoconfig::onDiscoverHubStage1Success, this, _1, _2),
+ ndn::bind(&NdnAutoconfig::discoverHubStage2, this, _1, "Timeout"));
+
+ m_face.processEvents();
+ }
+
+ // First stage OnData Callback
+ void
+ onDiscoverHubStage1Success(const ndn::Interest& interest, ndn::Data& data)
+ {
+ const ndn::Block& content = data.getContent();
+ content.parse();
+
+ // Get Uri
+ ndn::Block::element_const_iterator bockValue = content.find(ndn::tlv::nfd::Uri);
+ if (bockValue == content.elements_end())
+ {
+ discoverHubStage2(interest, "Incorrect reply to stage1");
+ return;
+ }
+ std::string faceMgmtUri(reinterpret_cast<const char*>(bockValue->value()), bockValue->value_size());
+ connectToHub(faceMgmtUri);
+ }
+
+ // First stage OnTimeout callback - start 2nd stage
+ void
+ discoverHubStage2(const ndn::Interest& interest, const std::string& message)
+ {
+ std::cerr << message << std::endl;
+ std::cerr << "Stage 2: Trying DNS query with default suffix..." << std::endl;
+
+ _res.retry = 2;
+ _res.ndots = 10;
+
+ QueryAnswer queryAnswer;
+
+ int answerSize = res_search("_ndn._udp",
+ ns_c_in,
+ ns_t_srv,
+ queryAnswer.buf,
+ sizeof(queryAnswer));
+
+ // 2nd stage failed - move on to the third stage
+ if (answerSize < 0)
+ {
+ discoverHubStage3("Failed to find NDN router using default suffix DNS query");
+ }
+ else
+ {
+ bool isParsed = parseHostAndConnectToHub(queryAnswer, answerSize);
+ if (isParsed == false)
+ {
+ // Failed to parse DNS response, try stage 3
+ discoverHubStage3("Failed to parse DNS response");
+ }
+ }
+ }
+
+ // Second stage OnTimeout callback
+ void
+ discoverHubStage3(const std::string& message)
+ {
+ std::cerr << message << std::endl;
+ std::cerr << "Stage 3: Trying to find home router..." << std::endl;
+
+ ndn::KeyChain keyChain;
+ ndn::Name identity = keyChain.getDefaultIdentity();
+ std::string serverName = "_ndn._udp.";
+
+ for (ndn::Name::const_reverse_iterator i = identity.rbegin(); i != identity.rend(); i++)
+ {
+ serverName.append(i->toEscapedString());
+ serverName.append(".");
+ }
+ serverName += "_homehub._autoconf.named-data.net";
+ std::cerr << "Stage3: About to query for a home router: " << serverName << std::endl;
+
+ QueryAnswer queryAnswer;
+
+ int answerSize = res_query(serverName.c_str(),
+ ns_c_in,
+ ns_t_srv,
+ queryAnswer.buf,
+ sizeof(queryAnswer));
+
+
+ // 3rd stage failed - abort
+ if (answerSize < 0)
+ {
+ std::cerr << "Failed to find a home router" << std::endl;
+ std::cerr << "exit" << std::endl;
+ }
+ else
+ {
+ bool isParsed = parseHostAndConnectToHub(queryAnswer, answerSize);
+ if (isParsed == false)
+ {
+ // Failed to parse DNS response
+ throw Error("Failed to parse DNS response");
+ }
+ }
+
+ }
+
+ void
+ connectToHub(const std::string& uri)
+ {
+ std::cerr << "about to connect to: " << uri << std::endl;
+ ndn::nfd::FaceManagementOptions faceOptions;
+
+ faceOptions.setUri(uri);
+ startFaceCommand("create",
+ faceOptions,
+ bind(&NdnAutoconfig::onHubConnectSuccess, this, _1, "Succesfully created face: "),
+ bind(&NdnAutoconfig::onHubConnectError, this, _1, "Failed to create face: "));
+ }
+
+ void
+ onHubConnectSuccess(const ndn::nfd::FaceManagementOptions& resp, const std::string& message)
+ {
+ std::cerr << message << resp << std::endl;
+ }
+
+ void
+ onHubConnectError(const std::string& error, const std::string& message)
+ {
+ throw Error(message + ": " + error);
+ }
+
+
+ bool parseHostAndConnectToHub(QueryAnswer& queryAnswer, int answerSize)
+ {
+ // The references of the next classes are:
+ // http://www.diablotin.com/librairie/networking/dnsbind/ch14_02.htm
+ // https://gist.github.com/mologie/6027597
+
+ class rechdr
+ {
+ public:
+ uint16_t type;
+ uint16_t iclass;
+ uint32_t ttl;
+ uint16_t length;
+ };
+
+ class srv_t
+ {
+ public:
+ uint16_t priority;
+ uint16_t weight;
+ uint16_t port;
+ uint8_t* target;
+ };
+
+ if (ntohs(queryAnswer.header.ancount) == 0)
+ {
+ std::cerr << "No records found\n" << std::endl;
+ return false;
+ }
+
+ uint8_t* blob = queryAnswer.buf + NS_HFIXEDSZ;
+
+ blob += dn_skipname(blob, queryAnswer.buf + answerSize) + NS_QFIXEDSZ;
+
+ for (int i = 0; i < ntohs(queryAnswer.header.ancount); i++)
+ {
+ char hostName[NS_MAXDNAME];
+ int domainNameSize = dn_expand(queryAnswer.buf,
+ queryAnswer.buf + answerSize,
+ blob,
+ hostName,
+ NS_MAXDNAME);
+ if (domainNameSize < 0)
+ {
+ return false;
+ }
+
+ blob += domainNameSize;
+
+ rechdr* header = reinterpret_cast<rechdr*>(&blob[0]);
+ srv_t* server = reinterpret_cast<srv_t*>(&blob[sizeof(rechdr)]);
+
+ domainNameSize = dn_expand(queryAnswer.buf,
+ queryAnswer.buf + answerSize,
+ blob + 16,
+ hostName,
+ NS_MAXDNAME);
+ if (domainNameSize < 0)
+ {
+ return false;
+ }
+ uint16_t convertedPort = be16toh(server->port);
+ std::string uri = "udp://";
+ uri.append(hostName);
+ uri.append(":");
+ uri.append(boost::lexical_cast<std::string>(convertedPort));
+
+ connectToHub(uri);
+ return true;
+ }
+ }
+};
+
+
+int
+main()
+{
+ ndn::Face face;
+ NdnAutoconfig autoConfig(face);
+ try
+ {
+ autoConfig.discoverHubStage1();
+ }
+ catch (const std::exception& error)
+ {
+ std::cerr << "ERROR: " << error.what() << std::endl;
+ }
+ return 0;
+}