blob: 3059dc404def3039d73945b646b95364cd54aa2b [file] [log] [blame]
/* -*- 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/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
namespace tools {
class NdnAutoconfig
{
public:
union QueryAnswer
{
HEADER header;
uint8_t buf[NS_PACKETSZ];
};
class Error : public std::runtime_error
{
public:
explicit
Error(const std::string& what)
: std::runtime_error(what)
{
}
};
explicit
NdnAutoconfig()
: m_controller(m_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(ndn::time::milliseconds(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 blockValue = content.find(ndn::tlv::nfd::Uri);
if (blockValue == content.elements_end())
{
discoverHubStage2(interest, "Incorrect reply to stage1");
return;
}
std::string faceMgmtUri(reinterpret_cast<const char*>(blockValue->value()),
blockValue->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;
m_controller.start<ndn::nfd::FaceCreateCommand>(
ndn::nfd::ControlParameters()
.setUri(uri),
bind(&NdnAutoconfig::onHubConnectSuccess, this,
_1, "Succesfully created face: "),
bind(&NdnAutoconfig::onHubConnectError, this,
_1, _2, "Failed to create face: ")
);
}
void
onHubConnectSuccess(const ndn::nfd::ControlParameters& resp, const std::string& message)
{
std::cerr << message << resp << std::endl;
}
void
onHubConnectError(uint32_t code, const std::string& error, const std::string& message)
{
std::ostringstream os;
os << message << ": " << error << " (code: " << code << ")";
throw Error(os.str());
}
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
struct rechdr
{
uint16_t type;
uint16_t iclass;
uint32_t ttl;
uint16_t length;
};
struct srv_t
{
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;
domainNameSize = dn_expand(queryAnswer.buf,
queryAnswer.buf + answerSize,
blob + 16,
hostName,
NS_MAXDNAME);
if (domainNameSize < 0)
{
return false;
}
srv_t* server = reinterpret_cast<srv_t*>(&blob[sizeof(rechdr)]);
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;
}
return false;
}
private:
ndn::Face m_face;
ndn::nfd::Controller m_controller;
};
} // namespace tools
int
main()
{
try
{
tools::NdnAutoconfig autoConfigInstance;
autoConfigInstance.discoverHubStage1();
}
catch (const std::exception& error)
{
std::cerr << "ERROR: " << error.what() << std::endl;
}
return 0;
}