premiere-libtorrent/test/test_dht.cpp

/*

Copyright (c) 2008, Arvid Norberg
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in
      the documentation and/or other materials provided with the distribution.
    * Neither the name of the author nor the names of its
      contributors may be used to endorse or promote products derived
      from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.

*/

#ifndef TORRENT_DISABLE_DHT

#include "libtorrent/config.hpp"
#include "libtorrent/session.hpp"
#include "libtorrent/kademlia/node.hpp" // for verify_message
#include "libtorrent/bencode.hpp"
#include "libtorrent/socket_io.hpp" // for hash_address
#include "libtorrent/broadcast_socket.hpp" // for supports_ipv6
#include "libtorrent/performance_counters.hpp" // for counters
#include "libtorrent/random.hpp"
#include "libtorrent/ed25519.hpp"
#include "libtorrent/hex.hpp" // to_hex, from_hex

#include "libtorrent/kademlia/node_id.hpp"
#include "libtorrent/kademlia/routing_table.hpp"
#include "libtorrent/kademlia/item.hpp"
#include "libtorrent/kademlia/dht_observer.hpp"

#include <numeric>
#include <cstdarg>
#include <tuple>
#include <iostream>

#include "test.hpp"
#include "setup_transfer.hpp"

using namespace libtorrent;
using namespace libtorrent::dht;
using namespace std::placeholders;

static sha1_hash to_hash(char const* s)
{
	sha1_hash ret;
	from_hex(s, 40, (char*)&ret[0]);
	return ret;
}

void add_and_replace(libtorrent::dht::node_id& dst, libtorrent::dht::node_id const& add)
{
	bool carry = false;
	for (int k = 19; k >= 0; --k)
	{
		int sum = dst[k] + add[k] + (carry?1:0);
		dst[k] = sum & 255;
		carry = sum > 255;
	}
}

void node_push_back(void* userdata, libtorrent::dht::node_entry const& n)
{
	using namespace libtorrent::dht;
	std::vector<node_entry>* nv = (std::vector<node_entry>*)userdata;
	nv->push_back(n);
}

static void nop(void* userdata, libtorrent::dht::node_entry const& n) {}
static void nop_node() {}

std::list<std::pair<udp::endpoint, entry> > g_sent_packets;

struct mock_socket final : udp_socket_interface
{
	bool has_quota() override { return true; }
	bool send_packet(entry& msg, udp::endpoint const& ep) override
	{
		// TODO: ideally the mock_socket would contain this queue of packets, to
		// make tests independent
		g_sent_packets.push_back(std::make_pair(ep, msg));
		return true;
	}
};

sha1_hash generate_next()
{
	sha1_hash ret;
	for (int i = 0; i < 20; ++i) ret[i] = rand() & 0xff;
	return ret;
}

std::array<char, 64> generate_key()
{
	std::array<char, 64> ret;
	for (int i = 0; i < 64; ++i) ret[i] = rand() & 0xff;
	return ret;
}

static const std::string no;

std::list<std::pair<udp::endpoint, entry> >::iterator
find_packet(udp::endpoint ep)
{
	return std::find_if(g_sent_packets.begin(), g_sent_packets.end()
		, [&ep] (std::pair<udp::endpoint, entry> const& p)
		{ return p.first == ep; });
}

void lazy_from_entry(entry const& e, bdecode_node& l)
{
	error_code ec;
	static char inbuf[1500];
	int len = bencode(inbuf, e);
	int ret = bdecode(inbuf, inbuf + len, l, ec);
	TEST_CHECK(ret == 0);
}

void write_peers(entry::dictionary_type& r, std::set<tcp::endpoint> const& peers)
{
	entry::list_type& pe = r["values"].list();
	for (auto const& p : peers)
	{
		std::string endpoint(18, '\0');
		std::string::iterator out = endpoint.begin();
		libtorrent::detail::write_endpoint(p, out);
		endpoint.resize(out - endpoint.begin());
		pe.push_back(entry(endpoint));
	}
}

struct msg_args
{
	msg_args& info_hash(char const* i)
	{ if (i) a["info_hash"] = std::string(i, 20); return *this; }

	msg_args& name(char const* n)
	{ if (n) a["n"] = n; return *this; }

	msg_args& token(std::string t)
	{ a["token"] = t; return *this; }

	msg_args& port(int p)
	{ a["port"] = p; return *this; }

	msg_args& target(char const* t)
	{ if (t) a["target"] = std::string(t, 20); return *this; }

	msg_args& value(entry const& v)
	{ a["v"] = v; return *this; }

	msg_args& scrape(bool s)
	{ a["scrape"] = s ? 1 : 0; return *this; }

	msg_args& seed(bool s)
	{ a["seed"] = s ? 1 : 0; return *this; }

	msg_args& key(std::string k)
	{ a["k"] = k; return *this; }

	msg_args& sig(std::string s)
	{ a["sig"] = s; return *this; }

	msg_args& seq(int s)
	{ a["seq"] = s; return *this; }

	msg_args& cas(boost::int64_t c)
	{ a["cas"] = c; return *this; }

	msg_args& nid(sha1_hash const& n)
	{ a["id"] = n.to_string(); return *this; }

	msg_args& salt(char const* s)
	{ if (s) a["salt"] = s; return *this; }

	msg_args& want(std::string w)
	{ a["want"].list().push_back(w); return *this; }

	msg_args& nodes(nodes_t const& n)
	{ if (!n.empty()) dht::write_nodes_entry(a["nodes"], n); return *this; }

	msg_args& nodes6(nodes_t const& n)
	{ if (!n.empty()) dht::write_nodes_entry(a["nodes6"], n); return *this; }

	msg_args& peers(std::set<tcp::endpoint> const& p)
	{ if (!p.empty()) write_peers(a.dict(), p); return *this; }

	entry a;
};

void send_dht_request(node& node, char const* msg, udp::endpoint const& ep
	, bdecode_node* reply, msg_args const& args = msg_args()
	, char const* t = "10", bool has_response = true)
{
	// we're about to clear out the backing buffer
	// for this lazy_entry, so we better clear it now
	reply->clear();
	entry e;
	e["q"] = msg;
	e["t"] = t;
	e["y"] = "q";
	e["a"] = args.a;
	e["a"].dict().insert(std::make_pair("id", generate_next().to_string()));
	char msg_buf[1500];
	int size = bencode(msg_buf, e);

	bdecode_node decoded;
	error_code ec;
	bdecode(msg_buf, msg_buf + size, decoded, ec);
	if (ec) std::fprintf(stderr, "bdecode failed: %s\n", ec.message().c_str());

	dht::msg m(decoded, ep);
	node.incoming(m);

	// If the request is supposed to get a response, by now the node should have 
	// invoked the send function and put the response in g_sent_packets
	std::list<std::pair<udp::endpoint, entry> >::iterator i = find_packet(ep);
	if (has_response)
	{
		if (i == g_sent_packets.end())
		{
			TEST_ERROR("not response from DHT node");
			return;
		}

		lazy_from_entry(i->second, *reply);
		g_sent_packets.erase(i);

		return;
	}

	// this request suppose won't be responsed.
	if (i != g_sent_packets.end())
	{
		TEST_ERROR("shouldn't have response from DHT node");
		return;
	}
}

void send_dht_response(node& node, bdecode_node const& request, udp::endpoint const& ep
	, msg_args const& args = msg_args())
{
	entry e;
	e["y"] = "r";
	e["t"] = request.dict_find_string_value("t");
//	e["ip"] = endpoint_to_bytes(ep);
	e["r"] = args.a;
	e["r"].dict().insert(std::make_pair("id", generate_next().to_string()));
	char msg_buf[1500];
	int size = bencode(msg_buf, e);

	bdecode_node decoded;
	error_code ec;
	bdecode(msg_buf, msg_buf + size, decoded, ec);
	if (ec) std::fprintf(stderr, "bdecode failed: %s\n", ec.message().c_str());

	dht::msg m(decoded, ep);
	node.incoming(m);
}

struct announce_item
{
	sha1_hash next;
	int num_peers;
	entry ent;
	sha1_hash target;
	void gen()
	{
		num_peers = (rand() % 5) + 2;
		ent["next"] = next.to_string();
		ent["A"] = "a";
		ent["B"] = "b";
		ent["num_peers"] = num_peers;

		char buf[512];
		char* ptr = buf;
		int len = bencode(ptr, ent);
		target = hasher(buf, len).final();
	}
};

void announce_immutable_items(node& node, udp::endpoint const* eps
	, announce_item const* items, int num_items)
{
	std::string token;
	for (int i = 0; i < 1000; ++i)
	{
		for (int j = 0; j < num_items; ++j)
		{
			if ((i % items[j].num_peers) == 0) continue;
			bdecode_node response;
			send_dht_request(node, "get", eps[i], &response
				, msg_args().target((char const*)&items[j].target[0]));
			
			key_desc_t desc[] =
			{
				{ "r", bdecode_node::dict_t, 0, key_desc_t::parse_children },
					{ "id", bdecode_node::string_t, 20, 0},
					{ "token", bdecode_node::string_t, 0, 0},
					{ "ip", bdecode_node::string_t, 0, key_desc_t::optional | key_desc_t::last_child},
				{ "y", bdecode_node::string_t, 1, 0},
			};

			bdecode_node parsed[5];
			char error_string[200];

//			std::fprintf(stderr, "msg: %s\n", print_entry(response).c_str());
			int ret = verify_message(response, desc, parsed, error_string
				, sizeof(error_string));
			if (ret)
			{
				TEST_EQUAL(parsed[4].string_value(), "r");
				token = parsed[2].string_value();
//				std::fprintf(stderr, "got token: %s\n", token.c_str());
			}
			else
			{
				std::fprintf(stderr, "msg: %s\n", print_entry(response).c_str());
				std::fprintf(stderr, "   invalid get response: %s\n", error_string);
				TEST_ERROR(error_string);
			}

			if (parsed[3])
			{
				address_v4::bytes_type b;
				memcpy(&b[0], parsed[3].string_ptr(), b.size());
				address_v4 addr(b);
				TEST_EQUAL(addr, eps[i].address());
			}

			send_dht_request(node, "put", eps[i], &response
				, msg_args()
					.token(token)
					.target((char const*)&items[j].target[0])
					.value(items[j].ent));

			key_desc_t desc2[] =
			{
				{ "y", bdecode_node::string_t, 1, 0 }
			};

			bdecode_node parsed2[1];
			ret = verify_message(response, desc2, parsed2, error_string
				, sizeof(error_string));
			if (ret)
			{
				if (parsed2[0].string_value() != "r")
					std::fprintf(stderr, "msg: %s\n", print_entry(response).c_str());

				TEST_EQUAL(parsed2[0].string_value(), "r");
			}
			else
			{
				std::fprintf(stderr, "msg: %s\n", print_entry(response).c_str());
				std::fprintf(stderr, "   invalid put response: %s\n", error_string);
				TEST_ERROR(error_string);
			}
		}
	}

	std::set<int> items_num;
	for (int j = 0; j < num_items; ++j)
	{
		bdecode_node response;
		send_dht_request(node, "get", eps[j], &response
			, msg_args().target((char const*)&items[j].target[0]));

		key_desc_t desc[] =
		{
			{ "r", bdecode_node::dict_t, 0, key_desc_t::parse_children },
				{ "v", bdecode_node::dict_t, 0, 0},
				{ "id", bdecode_node::string_t, 20, key_desc_t::last_child},
			{ "y", bdecode_node::string_t, 1, 0},
		};

		bdecode_node parsed[4];
		char error_string[200];

		int ret = verify_message(response, desc, parsed, error_string
			, sizeof(error_string));
		if (ret)
		{
			items_num.insert(items_num.begin(), j);
		}
	}

	// TODO: check to make sure the "best" items are stored
	TEST_EQUAL(items_num.size(), 4);
}

int sum_distance_exp(int s, node_entry const& e, node_id const& ref)
{
	return s + distance_exp(e.id, ref);
}

std::vector<tcp::endpoint> g_got_peers;

void get_peers_cb(std::vector<tcp::endpoint> const& peers)
{
	g_got_peers.insert(g_got_peers.end(), peers.begin(), peers.end());
}

std::vector<dht::item> g_got_items;
dht::item g_put_item;
int g_put_count;

void get_mutable_item_cb(dht::item const& i, bool a)
{
	if (!a) return;
	if (!i.empty())
		g_got_items.push_back(i);
}

void put_mutable_item_data_cb(dht::item& i)
{
	if (!i.empty())
		g_got_items.push_back(i);

	TEST_CHECK(!g_put_item.empty());
	i = g_put_item;
	g_put_count++;
}

void put_mutable_item_cb(dht::item const&, int num, int expect)
{
	TEST_EQUAL(num, expect);
}

void get_immutable_item_cb(dht::item const& i)
{
	if (!i.empty())
		g_got_items.push_back(i);
}

void put_immutable_item_cb(int num, int expect)
{
	TEST_EQUAL(num, expect);
}

struct obs : dht::dht_observer
{
	virtual void set_external_address(address const& addr
		, address const& source) override
	{}

	virtual address external_address(udp proto) override
	{
		return address_v4::from_string("236.0.0.1");
	}
	virtual void get_peers(sha1_hash const& ih) override {}
	virtual void outgoing_get_peers(sha1_hash const& target
		, sha1_hash const& sent_target, udp::endpoint const& ep) override {}
	virtual void announce(sha1_hash const& ih, address const& addr, int port) override {}
#ifndef TORRENT_DISABLE_LOGGING
	virtual void log(dht_logger::module_t l, char const* fmt, ...) override
	{
		va_list v;
		va_start(v, fmt);
		char buf[1024];
		vsnprintf(buf, sizeof(buf), fmt, v);
		va_end(v);
		m_log.push_back(buf);
	}
	virtual void log_packet(message_direction_t dir, char const* pkt, int len
		, udp::endpoint node) override {}
#endif
	virtual bool on_dht_request(char const* query, int query_len
		, dht::msg const& request, entry& response) override { return false; }

#ifndef TORRENT_DISABLE_LOGGING
	std::vector<std::string> m_log;
#endif
};

dht_settings test_settings()
{
	dht_settings sett;
	sett.max_torrents = 4;
	sett.max_dht_items = 4;
	sett.enforce_node_id = false;
	return sett;
}

// TODO: test obfuscated_get_peers
// TODO: 2 split this test up into smaller test cases
void do_test_dht(address(&rand_addr)())
{
	dht_settings sett = test_settings();
	mock_socket s;
	obs observer;
	counters cnt;
	udp::endpoint source(rand_addr(), 20);
	std::map<std::string, node*> nodes;
	dht::node node(source.protocol(), &s, sett
		, node_id(0), &observer, cnt, nodes);

	// DHT should be running on port 48199 now
	bdecode_node response;
	char error_string[200];
	bool ret;

	// ====== ping ======
	send_dht_request(node, "ping", source, &response);

	dht::key_desc_t pong_desc[] = {
		{"y", bdecode_node::string_t, 1, 0},
		{"t", bdecode_node::string_t, 2, 0},
		{"r", bdecode_node::dict_t, 0, key_desc_t::parse_children},
			{"id", bdecode_node::string_t, 20, key_desc_t::last_child},
	};

	bdecode_node pong_keys[4];

	std::fprintf(stderr, "msg: %s\n", print_entry(response).c_str());
	ret = dht::verify_message(response, pong_desc, pong_keys, error_string
		, sizeof(error_string));
	TEST_CHECK(ret);
	if (ret)
	{
		TEST_CHECK(pong_keys[0].string_value() == "r");
		TEST_CHECK(pong_keys[1].string_value() == "10");
	}
	else
	{
		std::fprintf(stderr, "   invalid ping response: %s\n", error_string);
	}

	// ====== invalid message ======

	send_dht_request(node, "find_node", source, &response);

	dht::key_desc_t err_desc[] = {
		{"y", bdecode_node::string_t, 1, 0},
		{"e", bdecode_node::list_t, 2, 0}
	};

	bdecode_node err_keys[2];

	std::fprintf(stderr, "msg: %s\n", print_entry(response).c_str());
	ret = dht::verify_message(response, err_desc, err_keys, error_string
		, sizeof(error_string));
	TEST_CHECK(ret);
	if (ret)
	{
		TEST_CHECK(err_keys[0].string_value() == "e");
		if (err_keys[1].list_at(0).type() == bdecode_node::int_t
			&& err_keys[1].list_at(1).type() == bdecode_node::string_t)
		{
			TEST_CHECK(err_keys[1].list_at(1).string_value() == "missing 'target' key");
		}
		else
		{
			TEST_ERROR("invalid error response");
		}
	}
	else
	{
		std::fprintf(stderr, "   invalid error response: %s\n", error_string);
	}

	// ====== get_peers ======

	send_dht_request(node, "get_peers", source, &response
		, msg_args().info_hash("01010101010101010101"));

	dht::key_desc_t peer1_desc[] = {
		{"y", bdecode_node::string_t, 1, 0},
		{"r", bdecode_node::dict_t, 0, key_desc_t::parse_children},
			{"token", bdecode_node::string_t, 0, 0},
			{"id", bdecode_node::string_t, 20, key_desc_t::last_child},
	};

	bdecode_node peer1_keys[4];

	std::string token;
	std::fprintf(stderr, "msg: %s\n", print_entry(response).c_str());
	ret = dht::verify_message(response, peer1_desc, peer1_keys, error_string
		, sizeof(error_string));
	TEST_CHECK(ret);
	if (ret)
	{
		TEST_CHECK(peer1_keys[0].string_value() == "r");
		token = peer1_keys[2].string_value();
//		std::fprintf(stderr, "got token: %s\n", token.c_str());
	}
	else
	{
		std::fprintf(stderr, "msg: %s\n", print_entry(response).c_str());
		std::fprintf(stderr, "   invalid get_peers response: %s\n", error_string);
	}

	// ====== announce ======

	send_dht_request(node, "announce_peer", source, &response
		, msg_args()
			.info_hash("01010101010101010101")
			.name("test")
			.token(token)
			.port(8080));


	dht::key_desc_t ann_desc[] = {
		{"y", bdecode_node::string_t, 1, 0},
		{"r", bdecode_node::dict_t, 0, key_desc_t::parse_children},
			{"id", bdecode_node::string_t, 20, key_desc_t::last_child},
	};

	bdecode_node ann_keys[3];

	std::fprintf(stderr, "msg: %s\n", print_entry(response).c_str());
	ret = dht::verify_message(response, ann_desc, ann_keys, error_string
		, sizeof(error_string));
	TEST_CHECK(ret);
	if (ret)
	{
		TEST_CHECK(ann_keys[0].string_value() == "r");
	}
	else
	{
		std::fprintf(stderr, "   invalid announce response: %s\n", error_string);
	}

	init_rand_address();

	// announce from 100 random IPs and make sure scrape works
	// 50 downloaders and 50 seeds
	for (int i = 0; i < 100; ++i)
	{
		source = udp::endpoint(rand_addr(), 6000);
		send_dht_request(node, "get_peers", source, &response
			, msg_args().info_hash("01010101010101010101"));

		ret = dht::verify_message(response, peer1_desc, peer1_keys, error_string
			, sizeof(error_string));

		if (ret)
		{
			TEST_CHECK(peer1_keys[0].string_value() == "r");
			token = peer1_keys[2].string_value();
//			std::fprintf(stderr, "got token: %s\n", token.c_str());
		}
		else
		{
			std::fprintf(stderr, "msg: %s\n", print_entry(response).c_str());
			std::fprintf(stderr, "   invalid get_peers response: %s\n", error_string);
		}
		response.clear();
		send_dht_request(node, "announce_peer", source, &response
			, msg_args()
				.info_hash("01010101010101010101")
				.name("test")
				.token(token)
				.port(8080)
				.seed(i >= 50));

		response.clear();
	}

	// ====== get_peers ======

	send_dht_request(node, "get_peers", source, &response
		, msg_args().info_hash("01010101010101010101").scrape(true));

	dht::key_desc_t peer2_desc[] = {
		{"y", bdecode_node::string_t, 1, 0},
		{"r", bdecode_node::dict_t, 0, key_desc_t::parse_children},
			{"BFpe", bdecode_node::string_t, 256, 0},
			{"BFsd", bdecode_node::string_t, 256, 0},
			{"id", bdecode_node::string_t, 20, key_desc_t::last_child},
	};

	bdecode_node peer2_keys[5];

	std::fprintf(stderr, "msg: %s\n", print_entry(response).c_str());
	ret = dht::verify_message(response, peer2_desc, peer2_keys, error_string
		, sizeof(error_string));
	TEST_CHECK(ret);
	if (ret)
	{
		TEST_CHECK(peer2_keys[0].string_value() == "r");
		TEST_EQUAL(peer2_keys[1].dict_find_string_value("n"), "test");

		bloom_filter<256> downloaders;
		bloom_filter<256> seeds;
		downloaders.from_string(peer2_keys[2].string_ptr());
		seeds.from_string(peer2_keys[3].string_ptr());

		std::fprintf(stderr, "seeds: %f\n", seeds.size());
		std::fprintf(stderr, "downloaders: %f\n", downloaders.size());

		TEST_CHECK(fabs(seeds.size() - 50.f) <= 3.f);
		TEST_CHECK(fabs(downloaders.size() - 50.f) <= 3.f);
	}
	else
	{
		std::fprintf(stderr, "   invalid get_peers response: %s\n", error_string);
	}

	// ====== test node ID testing =====

	{
		node_id rnd = generate_secret_id();
		TEST_CHECK(verify_secret_id(rnd));

		rnd[19] ^= 0x55;
		TEST_CHECK(!verify_secret_id(rnd));

		rnd = generate_random_id();
		make_id_secret(rnd);
		TEST_CHECK(verify_secret_id(rnd));
	}

	// ====== test node ID enforcement ======

	// enable node_id enforcement
	sett.enforce_node_id = true;

	node_id nid;
	if (source.protocol() == udp::v4())
	{
		// this is one of the test vectors from:
		// http://libtorrent.org/dht_sec.html
		source = udp::endpoint(address::from_string("124.31.75.21"), 1);
		nid = to_hash("5fbfbff10c5d6a4ec8a88e4c6ab4c28b95eee401");
	}
	else
	{
		source = udp::endpoint(address::from_string("2001:b829:2123:be84:e16c:d6ae:5290:49f1"), 1);
		nid = to_hash("0a8ad123be84e16cd6ae529049f1f1bbe9ebb304");
	}

	// verify that we reject invalid node IDs
	// this is now an invalid node-id for 'source'
	nid[0] = 0x18;
	int nodes_num = node.size().get<0>();
	send_dht_request(node, "find_node", source, &response
		, msg_args().target("0101010101010101010101010101010101010101").nid(nid));

	ret = dht::verify_message(response, err_desc, err_keys, error_string
		, sizeof(error_string));
	TEST_CHECK(ret);
	if (ret)
	{
		TEST_CHECK(err_keys[0].string_value() == "e");
		if (err_keys[1].list_at(0).type() == bdecode_node::int_t
			&& err_keys[1].list_at(1).type() == bdecode_node::string_t)
		{
			TEST_CHECK(err_keys[1].list_at(1).string_value() == "invalid node ID");
		}
		else
		{
			std::fprintf(stderr, "msg: %s\n", print_entry(response).c_str());
			TEST_ERROR("invalid error response");
		}
	}
	else
	{
		std::fprintf(stderr, "msg: %s\n", print_entry(response).c_str());
		std::fprintf(stderr, "   invalid error response: %s\n", error_string);
	}

	// a node with invalid node-id shouldn't be added to routing table.
	TEST_EQUAL(node.size().get<0>(), nodes_num);

	// now the node-id is valid.
	if (source.protocol() == udp::v4())
		nid[0] = 0x5f;
	else
		nid[0] = 0x0a;
	send_dht_request(node, "find_node", source, &response
		, msg_args().target("0101010101010101010101010101010101010101").nid(nid));

	dht::key_desc_t nodes_desc[] = {
		{"y", bdecode_node::string_t, 1, 0},
		{"r", bdecode_node::dict_t, 0, key_desc_t::parse_children},
			{"id", bdecode_node::string_t, 20, key_desc_t::last_child},
	};

	bdecode_node nodes_keys[3];

	std::fprintf(stderr, "msg: %s\n", print_entry(response).c_str());
	ret = dht::verify_message(response, nodes_desc, nodes_keys, error_string
		, sizeof(error_string));
	TEST_CHECK(ret);
	if (ret)
	{
		TEST_CHECK(nodes_keys[0].string_value() == "r");
	}
	else
	{
		std::fprintf(stderr, "msg: %s\n", print_entry(response).c_str());
		std::fprintf(stderr, "   invalid error response: %s\n", error_string);
	}
	// node with valid node-id should be added to routing table.
	TEST_EQUAL(node.size().get<0>(), nodes_num + 1);

	sett.enforce_node_id = false;

// ===========================

	bloom_filter<256> test;
	for (int i = 0; i < 256; ++i)
	{
		char adr[50];
		std::snprintf(adr, 50, "192.0.2.%d", i);
		address a = address::from_string(adr);
		sha1_hash iphash;
		hash_address(a, iphash);
		test.set(iphash);
	}

	if (supports_ipv6())
	{
		for (int i = 0; i < 0x3E8; ++i)
		{
			char adr[50];
			std::snprintf(adr, 50, "2001:db8::%x", i);
			address a = address::from_string(adr);
			sha1_hash iphash;
			hash_address(a, iphash);
			test.set(iphash);
		}
	}

	// these are test vectors from BEP 33
	// http://www.bittorrent.org/beps/bep_0033.html
	std::fprintf(stderr, "test.size: %f\n", test.size());
	std::fprintf(stderr, "%s\n", to_hex(test.to_string()).c_str());
	if (supports_ipv6())
	{
		TEST_CHECK(fabs(test.size() - 1224.93f) < 0.001);
		TEST_CHECK(to_hex(test.to_string()) == "f6c3f5eaa07ffd91bde89f777f26fb2bff37bdb8fb2bbaa2fd3ddde7bacfff75ee7ccbaefe5eedb1fbfaff67f6abff5e43ddbca3fd9b9ffdf4ffd3e9dff12d1bdf59db53dbe9fa5b7ff3b8fdfcde1afb8bedd7be2f3ee71ebbbfe93bcdeefe148246c2bc5dbff7e7efdcf24fd8dc7adffd8fffdfddfff7a4bbeedf5cb95ce81fc7fcff1ff4ffffdfe5f7fdcbb7fd79b3fa1fc77bfe07fff905b7b7ffc7fefeffe0b8370bb0cd3f5b7f2bd93feb4386cfdd6f7fd5bfaf2e9ebffffeecd67adbf7c67f17efd5d75eba6ffeba7fff47a91eb1bfbb53e8abfb5762abe8ff237279bfefbfeef5ffc5febfdfe5adffadfee1fb737ffffbfd9f6aeffeee76b6fd8f72ef");
	}
	else
	{
		TEST_CHECK(fabs(test.size() - 257.854f) < 0.001);
		TEST_CHECK(to_hex(test.to_string()) == "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");
	}

	response.clear();

	// ====== put ======

	init_rand_address();

	udp::endpoint eps[1000];

	for (int i = 0; i < 1000; ++i)
		eps[i] = udp::endpoint(rand_addr(), (rand() % 16534) + 1);

	announce_item items[] =
	{
		{ generate_next(), 1 },
		{ generate_next(), 2 },
		{ generate_next(), 3 },
		{ generate_next(), 4 },
		{ generate_next(), 5 },
		{ generate_next(), 6 },
		{ generate_next(), 7 },
		{ generate_next(), 8 }
	};

	for (int i = 0; i < int(sizeof(items)/sizeof(items[0])); ++i)
		items[i].gen();

	announce_immutable_items(node, eps, items, sizeof(items)/sizeof(items[0]));

	key_desc_t desc2[] =
	{
		{ "y", bdecode_node::string_t, 1, 0 }
	};

	bdecode_node desc2_keys[1];

	key_desc_t desc_error[] =
	{
		{ "e", bdecode_node::list_t, 2, 0 },
		{ "y", bdecode_node::string_t, 1, 0},
	};

	bdecode_node desc_error_keys[2];

	// ==== get / put mutable items ===

	std::pair<char const*, int> itemv;
	std::pair<char const*, int> empty_salt;
	empty_salt.first = NULL;
	empty_salt.second = 0;

	char signature[item_sig_len];
	char buffer[1200];
	int seq = 4;
	char private_key[item_sk_len];
	char public_key[item_pk_len];
	for (int with_salt = 0; with_salt < 2; ++with_salt)
	{
		seq = 4;
		std::fprintf(stderr, "\nTEST GET/PUT%s \ngenerating ed25519 keys\n\n"
			, with_salt ? " with-salt" : " no-salt");
		unsigned char seed[32];
		ed25519_create_seed(seed);

		ed25519_create_keypair((unsigned char*)public_key, (unsigned char*)private_key, seed);
		std::fprintf(stderr, "pub: %s priv: %s\n"
			, to_hex(std::string(public_key, item_pk_len)).c_str()
			, to_hex(std::string(private_key, item_sk_len)).c_str());

		TEST_CHECK(ret);

		std::pair<const char*, int> salt((char*)0, 0);
		if (with_salt)
			salt = std::pair<char const*, int>("foobar", 6);

		hasher h(public_key, 32);
		if (with_salt) h.update(salt.first, salt.second);
		sha1_hash target_id = h.final();

		std::fprintf(stderr, "target_id: %s\n"
			, to_hex(target_id.to_string()).c_str());

		send_dht_request(node, "get", source, &response
			, msg_args().target((char*)&target_id[0]));

		key_desc_t desc[] =
		{
			{ "r", bdecode_node::dict_t, 0, key_desc_t::parse_children },
			{ "id", bdecode_node::string_t, 20, 0},
			{ "token", bdecode_node::string_t, 0, 0},
			{ "ip", bdecode_node::string_t, 0, key_desc_t::optional | key_desc_t::last_child},
			{ "y", bdecode_node::string_t, 1, 0},
		};

		bdecode_node desc_keys[5];

		ret = verify_message(response, desc, desc_keys, error_string
			, sizeof(error_string));
		if (ret)
		{
			TEST_EQUAL(desc_keys[4].string_value(), "r");
			token = desc_keys[2].string_value();
			std::fprintf(stderr, "get response: %s\n"
				, print_entry(response).c_str());
			std::fprintf(stderr, "got token: %s\n", to_hex(token).c_str());
		}
		else
		{
			std::fprintf(stderr, "msg: %s\n", print_entry(response).c_str());
			std::fprintf(stderr, "   invalid get response: %s\n%s\n"
				, error_string, print_entry(response).c_str());
			TEST_ERROR(error_string);
		}

		itemv = std::pair<char const*, int>(buffer, bencode(buffer, items[0].ent));
		sign_mutable_item(itemv, salt, seq, public_key, private_key, signature);
		TEST_EQUAL(verify_mutable_item(itemv, salt, seq, public_key, signature), true);

		send_dht_request(node, "put", source, &response
			, msg_args()
				.token(token)
				.value(items[0].ent)
				.key(std::string(public_key, item_pk_len))
				.sig(std::string(signature, item_sig_len))
				.seq(seq)
				.salt(salt.first));

		ret = verify_message(response, desc2, desc2_keys, error_string
			, sizeof(error_string));
		if (ret)
		{
			std::fprintf(stderr, "put response: %s\n"
				, print_entry(response).c_str());
			TEST_EQUAL(desc2_keys[0].string_value(), "r");
		}
		else
		{
			std::fprintf(stderr, "   invalid put response: %s\n%s\n"
				, error_string, print_entry(response).c_str());
			TEST_ERROR(error_string);
		}

		send_dht_request(node, "get", source, &response
			, msg_args().target((char*)&target_id[0]));

		std::fprintf(stderr, "target_id: %s\n"
			, to_hex(target_id.to_string()).c_str());

		key_desc_t desc3[] =
		{
			{ "r", bdecode_node::dict_t, 0, key_desc_t::parse_children },
			{ "id", bdecode_node::string_t, 20, 0},
			{ "v", bdecode_node::none_t, 0, 0},
			{ "seq", bdecode_node::int_t, 0, 0},
			{ "sig", bdecode_node::string_t, 0, 0},
			{ "ip", bdecode_node::string_t, 0, key_desc_t::optional | key_desc_t::last_child},
			{ "y", bdecode_node::string_t, 1, 0},
		};

		bdecode_node desc3_keys[7];

		ret = verify_message(response, desc3, desc3_keys, error_string
			, sizeof(error_string));
		if (ret == 0)
		{
			std::fprintf(stderr, "msg: %s\n", print_entry(response).c_str());
			std::fprintf(stderr, "   invalid get response: %s\n%s\n"
				, error_string, print_entry(response).c_str());
			TEST_ERROR(error_string);
		}
		else
		{
			std::fprintf(stderr, "get response: %s\n"
				, print_entry(response).c_str());
			char value[1020];
			char* ptr = value;
			int value_len = bencode(ptr, items[0].ent);
			TEST_EQUAL(value_len, desc3_keys[2].data_section().second);
			TEST_CHECK(memcmp(desc3_keys[2].data_section().first, value, value_len) == 0);

			TEST_EQUAL(seq, desc3_keys[3].int_value());
		}

		// also test that invalid signatures fail!

		itemv.second = bencode(buffer, items[0].ent);
		sign_mutable_item(itemv, salt, seq, public_key, private_key, signature);
		TEST_EQUAL(verify_mutable_item(itemv, salt, seq, public_key, signature), 1);
		// break the signature
		signature[2] ^= 0xaa;

		std::fprintf(stderr, "PUT broken signature\n");

		TEST_CHECK(verify_mutable_item(itemv, salt, seq, public_key, signature) != 1);

		send_dht_request(node, "put", source, &response
			, msg_args()
				.token(token)
				.value(items[0].ent)
				.key(std::string(public_key, item_pk_len))
				.sig(std::string(signature, item_sig_len))
				.seq(seq)
				.salt(salt.first));

		ret = verify_message(response, desc_error, desc_error_keys, error_string
			, sizeof(error_string));
		if (ret)
		{
			std::fprintf(stderr, "put response: %s\n", print_entry(response).c_str());
			TEST_EQUAL(desc_error_keys[1].string_value(), "e");
			// 206 is the code for invalid signature
			TEST_EQUAL(desc_error_keys[0].list_int_value_at(0), 206);
		}
		else
		{
			std::fprintf(stderr, "   invalid put response: %s\n%s\n"
				, error_string, print_entry(response).c_str());
			TEST_ERROR(error_string);
		}

		// === test conditional get ===

		send_dht_request(node, "get", source, &response
			, msg_args().target((char*)&target_id[0]).seq(seq - 1));

		{
			bdecode_node r = response.dict_find_dict("r");
			TEST_CHECK(r.dict_find("v"));
			TEST_CHECK(r.dict_find("k"));
			TEST_CHECK(r.dict_find("sig"));
		}

		send_dht_request(node, "get", source, &response
			, msg_args().target((char*)&target_id[0]).seq(seq));

		{
			bdecode_node r = response.dict_find_dict("r");
			TEST_CHECK(!r.dict_find("v"));
			TEST_CHECK(!r.dict_find("k"));
			TEST_CHECK(!r.dict_find("sig"));
		}

		// === test CAS put ===

		// this is the sequence number we expect to be there
		boost::uint64_t cas = seq;

		// increment sequence number
		++seq;
		// put item 1
		itemv.second = bencode(buffer, items[1].ent);
		sign_mutable_item(itemv, salt, seq, public_key, private_key, signature);
		TEST_EQUAL(verify_mutable_item(itemv, salt, seq, public_key, signature), 1);

		TEST_CHECK(item_target_id(salt, public_key) == target_id);

		std::fprintf(stderr, "PUT CAS 1\n");

		send_dht_request(node, "put", source, &response
			, msg_args()
				.token(token)
				.value(items[1].ent)
				.key(std::string(public_key, item_pk_len))
				.sig(std::string(signature, item_sig_len))
				.seq(seq)
				.cas(cas)
				.salt(salt.first));

		ret = verify_message(response, desc2, desc2_keys, error_string
			, sizeof(error_string));
		if (ret)
		{
			std::fprintf(stderr, "put response: %s\n"
				, print_entry(response).c_str());
			TEST_EQUAL(desc2_keys[0].string_value(), "r");
		}
		else
		{
			std::fprintf(stderr, "   invalid put response: %s\n%s\n"
				, error_string, print_entry(response).c_str());
			TEST_ERROR(error_string);
		}

		std::fprintf(stderr, "PUT CAS 2\n");

		// put the same message again. This should fail because the
		// CAS hash is outdated, it's not the hash of the value that's
		// stored anymore
		send_dht_request(node, "put", source, &response
			, msg_args()
				.token(token)
				.value(items[1].ent)
				.key(std::string(public_key, item_pk_len))
				.sig(std::string(signature, item_sig_len))
				.seq(seq)
				.cas(cas)
				.salt(salt.first));

		ret = verify_message(response, desc_error, desc_error_keys, error_string
			, sizeof(error_string));
		if (ret)
		{
			std::fprintf(stderr, "put response: %s\n"
				, print_entry(response).c_str());
			TEST_EQUAL(desc_error_keys[1].string_value(), "e");
			// 301 is the error code for CAS hash mismatch
			TEST_EQUAL(desc_error_keys[0].list_int_value_at(0), 301);
		}
		else
		{
			std::fprintf(stderr, "   invalid put response: %s\n%s\nExpected failure 301 (CAS hash mismatch)\n"
				, error_string, print_entry(response).c_str());
			TEST_ERROR(error_string);
		}

	}

	{
		// test kademlia routing table
		dht_settings s;
		s.extended_routing_table = false;
		//	s.restrict_routing_ips = false;
		node_id id = to_hash("3123456789abcdef01232456789abcdef0123456");
		const int bucket_size = 10;
		dht::routing_table table(id, source.protocol(), bucket_size, s, &observer);
		std::vector<node_entry> nodes;
		TEST_EQUAL(table.size().get<0>(), 0);

		node_id tmp = id;
		node_id diff = to_hash("15764f7459456a9453f8719b09547c11d5f34061");

		address node_addr;
		address node_near_addr;
		if (source.protocol() == udp::v4())
		{
			node_addr = address_v4::from_string("4.4.4.4");
			node_near_addr = address_v4::from_string("4.4.4.5");
		}
		else
		{
			node_addr = address_v6::from_string("2001:1111:1111:1111:1111:1111:1111:1111");
			node_near_addr = address_v6::from_string("2001:1111:1111:1111:eeee:eeee:eeee:eeee");
		}

		// test a node with the same IP:port changing ID
		add_and_replace(tmp, diff);
		table.node_seen(tmp, udp::endpoint(node_addr, 4), 10);
		table.find_node(id, nodes, 0, 10);
		TEST_EQUAL(table.bucket_size(0), 1);
		TEST_EQUAL(table.size().get<0>(), 1);
		TEST_EQUAL(nodes.size(), 1);
		if (!nodes.empty())
		{
			TEST_EQUAL(nodes[0].id, tmp);
			TEST_EQUAL(nodes[0].addr(), node_addr);
			TEST_EQUAL(nodes[0].port(), 4);
			TEST_EQUAL(nodes[0].timeout_count, 0);
		}

		// set timeout_count to 1
		table.node_failed(tmp, udp::endpoint(node_addr, 4));

		nodes.clear();
		table.for_each_node(node_push_back, nop, &nodes);
		TEST_EQUAL(nodes.size(), 1);
		if (!nodes.empty())
		{
			TEST_EQUAL(nodes[0].id, tmp);
			TEST_EQUAL(nodes[0].addr(), node_addr);
			TEST_EQUAL(nodes[0].port(), 4);
			TEST_EQUAL(nodes[0].timeout_count, 1);
		}

		// add the exact same node again, it should set the timeout_count to 0
		table.node_seen(tmp, udp::endpoint(node_addr, 4), 10);
		nodes.clear();
		table.for_each_node(node_push_back, nop, &nodes);
		TEST_EQUAL(nodes.size(), 1);
		if (!nodes.empty())
		{
			TEST_EQUAL(nodes[0].id, tmp);
			TEST_EQUAL(nodes[0].addr(), node_addr);
			TEST_EQUAL(nodes[0].port(), 4);
			TEST_EQUAL(nodes[0].timeout_count, 0);
		}

		// test adding the same IP:port again with a new node ID (should replace the old one)
		add_and_replace(tmp, diff);
		table.node_seen(tmp, udp::endpoint(node_addr, 4), 10);
		table.find_node(id, nodes, 0, 10);
		TEST_EQUAL(table.bucket_size(0), 1);
		TEST_EQUAL(nodes.size(), 1);
		if (!nodes.empty())
		{
			TEST_EQUAL(nodes[0].id, tmp);
			TEST_EQUAL(nodes[0].addr(), node_addr);
			TEST_EQUAL(nodes[0].port(), 4);
		}

		// test adding the same node ID again with a different IP (should be ignored)
		table.node_seen(tmp, udp::endpoint(node_addr, 5), 10);
		table.find_node(id, nodes, 0, 10);
		TEST_EQUAL(table.bucket_size(0), 1);
		if (!nodes.empty())
		{
			TEST_EQUAL(nodes[0].id, tmp);
			TEST_EQUAL(nodes[0].addr(), node_addr);
			TEST_EQUAL(nodes[0].port(), 4);
		}

		// test adding a node that ends up in the same bucket with an IP
		// very close to the current one (should be ignored)
		// if restrict_routing_ips == true
		table.node_seen(tmp, udp::endpoint(node_near_addr, 5), 10);
		table.find_node(id, nodes, 0, 10);
		TEST_EQUAL(table.bucket_size(0), 1);
		if (!nodes.empty())
		{
			TEST_EQUAL(nodes[0].id, tmp);
			TEST_EQUAL(nodes[0].addr(), node_addr);
			TEST_EQUAL(nodes[0].port(), 4);
		}

		s.restrict_routing_ips = false;

		init_rand_address();

		add_and_replace(tmp, diff);
		table.node_seen(id, udp::endpoint(rand_addr(), rand()), 10);

		nodes.clear();
		for (int i = 0; i < 7000; ++i)
		{
			table.node_seen(tmp, udp::endpoint(rand_addr(), rand()), 20 + (tmp[19] & 0xff));
			add_and_replace(tmp, diff);
		}
		std::printf("active buckets: %d\n", table.num_active_buckets());
		TEST_EQUAL(table.num_active_buckets(), 10);
		TEST_CHECK(table.size().get<0>() >= 10 * 10);
		//#error test num_global_nodes
		//#error test need_refresh

#if defined TORRENT_DEBUG
		table.print_state(std::cerr);
#endif

		table.for_each_node(node_push_back, nop, &nodes);

		std::printf("nodes: %d\n", int(nodes.size()));

		std::vector<node_entry> temp;

		std::generate(tmp.begin(), tmp.end(), random_byte);
		table.find_node(tmp, temp, 0, int(nodes.size()) * 2);
		std::printf("returned-all: %d\n", int(temp.size()));
		TEST_EQUAL(temp.size(), nodes.size());

		// This makes sure enough of the nodes returned are actually
		// part of the closest nodes
		std::set<node_id> duplicates;

		const int reps = 50;

		for (int r = 0; r < reps; ++r)
		{
			std::generate(tmp.begin(), tmp.end(), random_byte);
			table.find_node(tmp, temp, 0, bucket_size * 2);
			std::printf("returned: %d\n", int(temp.size()));
			TEST_EQUAL(int(temp.size()), (std::min)(bucket_size * 2, int(nodes.size())));

			std::sort(nodes.begin(), nodes.end(), std::bind(&compare_ref
					, std::bind(&node_entry::id, _1)
					, std::bind(&node_entry::id, _2), tmp));

			int expected = std::accumulate(nodes.begin(), nodes.begin() + (bucket_size * 2)
				, 0, std::bind(&sum_distance_exp, _1, _2, tmp));
			int sum_hits = std::accumulate(temp.begin(), temp.end()
				, 0, std::bind(&sum_distance_exp, _1, _2, tmp));
			TEST_EQUAL(bucket_size * 2, int(temp.size()));
			std::printf("expected: %d actual: %d\n", expected, sum_hits);
			TEST_EQUAL(expected, sum_hits);

			duplicates.clear();
			// This makes sure enough of the nodes returned are actually
			// part of the closest nodes
			for (std::vector<node_entry>::iterator i = temp.begin()
				, end(temp.end()); i != end; ++i)
			{
				TEST_CHECK(duplicates.count(i->id) == 0);
				duplicates.insert(i->id);
			}
		}

		using namespace libtorrent::dht;

		char const* ips[] = {
			"124.31.75.21",
			"21.75.31.124",
			"65.23.51.170",
			"84.124.73.14",
			"43.213.53.83",
		};

		int rs[] = { 1,86,22,65,90 };

		boost::uint8_t prefixes[][3] =
		{
			{ 0x5f, 0xbf, 0xbf },
			{ 0x5a, 0x3c, 0xe9 },
			{ 0xa5, 0xd4, 0x32 },
			{ 0x1b, 0x03, 0x21 },
			{ 0xe5, 0x6f, 0x6c }
		};

		for (int i = 0; i < 5; ++i)
		{
			address a = address_v4::from_string(ips[i]);
			node_id id = generate_id_impl(a, rs[i]);
			TEST_CHECK(id[0] == prefixes[i][0]);
			TEST_CHECK(id[1] == prefixes[i][1]);
			TEST_CHECK((id[2] & 0xf8) == (prefixes[i][2] & 0xf8));

			TEST_CHECK(id[19] == rs[i]);
			std::fprintf(stderr, "IP address: %s r: %d node ID: %s\n", ips[i]
				, rs[i], to_hex(id.to_string()).c_str());
		}
	}

	// test traversal algorithms

	dht::key_desc_t find_node_desc[] = {
		{"y", bdecode_node::string_t, 1, 0},
		{"t", bdecode_node::string_t, 2, 0},
		{"q", bdecode_node::string_t, 9, 0},
		{"a", bdecode_node::dict_t, 0, key_desc_t::parse_children},
			{"id", bdecode_node::string_t, 20, 0},
			{"target", bdecode_node::string_t, 20, key_desc_t::optional},
			{"info_hash", bdecode_node::string_t, 20, key_desc_t::optional | key_desc_t::last_child},
	};

	bdecode_node find_node_keys[7];

	dht::key_desc_t get_peers_desc[] = {
		{"y", bdecode_node::string_t, 1, 0},
		{"t", bdecode_node::string_t, 2, 0},
		{"q", bdecode_node::string_t, 9, 0},
		{"a", bdecode_node::dict_t, 0, key_desc_t::parse_children},
			{"id", bdecode_node::string_t, 20, 0},
			{"info_hash", bdecode_node::string_t, 20, key_desc_t::last_child},
	};

	bdecode_node get_peers_keys[6];

	dht::key_desc_t get_item_desc[] = {
		{"y", bdecode_node::string_t, 1, 0},
		{"t", bdecode_node::string_t, 2, 0},
		{"q", bdecode_node::string_t, 3, 0},
		{"a", bdecode_node::dict_t, 0, key_desc_t::parse_children},
			{"id", bdecode_node::string_t, 20, 0},
			{"target", bdecode_node::string_t, 20, key_desc_t::last_child},
	};

	bdecode_node get_item_keys[6];


	// bootstrap

	g_sent_packets.clear();
	do
	{
		dht::node node(udp::v4(), &s, sett, (node_id::min)(), &observer, cnt, nodes);

		udp::endpoint initial_node(address_v4::from_string("4.4.4.4"), 1234);
		std::vector<udp::endpoint> nodesv;
		nodesv.push_back(initial_node);
		node.bootstrap(nodesv, std::bind(&nop_node));

		TEST_EQUAL(g_sent_packets.size(), 1);
		if (g_sent_packets.empty()) break;
		TEST_EQUAL(g_sent_packets.front().first, initial_node);

		lazy_from_entry(g_sent_packets.front().second, response);
		ret = verify_message(response, find_node_desc, find_node_keys, error_string
			, sizeof(error_string));
		if (ret)
		{
			TEST_EQUAL(find_node_keys[0].string_value(), "q");
			TEST_CHECK(find_node_keys[2].string_value() == "find_node"
				|| find_node_keys[2].string_value() == "get_peers");

			if (find_node_keys[0].string_value() != "q"
				|| (find_node_keys[2].string_value() != "find_node"
					&& find_node_keys[2].string_value() != "get_peers")) break;
		}
		else
		{
			std::fprintf(stderr, "   invalid find_node request: %s\n", print_entry(response).c_str());
			TEST_ERROR(error_string);
			break;
		}

		udp::endpoint found_node(address_v4::from_string("5.5.5.5"), 2235);
		nodes_t nodes;
		nodes.push_back(found_node);
		g_sent_packets.clear();
		send_dht_response(node, response, initial_node, msg_args().nodes(nodes));

		TEST_EQUAL(g_sent_packets.size(), 1);
		if (g_sent_packets.empty()) break;
		TEST_EQUAL(g_sent_packets.front().first, found_node);

		lazy_from_entry(g_sent_packets.front().second, response);
		ret = verify_message(response, find_node_desc, find_node_keys, error_string
			, sizeof(error_string));
		if (ret)
		{
			TEST_EQUAL(find_node_keys[0].string_value(), "q");
			TEST_CHECK(find_node_keys[2].string_value() == "find_node"
				|| find_node_keys[2].string_value() == "get_peers");
			if (find_node_keys[0].string_value() != "q" || (find_node_keys[2].string_value() != "find_node"
				&& find_node_keys[2].string_value() == "get_peers")) break;
		}
		else
		{
			std::fprintf(stderr, "   invalid find_node request: %s\n", print_entry(response).c_str());
			TEST_ERROR(error_string);
			break;
		}

		g_sent_packets.clear();
		send_dht_response(node, response, found_node);

		TEST_CHECK(g_sent_packets.empty());
		TEST_EQUAL(node.num_global_nodes(), 3);
	} while (false);

	// get_peers

	g_sent_packets.clear();
	do
	{
		dht::node_id target = to_hash("1234876923549721020394873245098347598635");
		dht::node node(udp::v4(), &s, sett, (node_id::min)(), &observer, cnt, nodes);

		udp::endpoint initial_node(address_v4::from_string("4.4.4.4"), 1234);
		node.m_table.add_node(initial_node);

		node.announce(target, 1234, false, get_peers_cb);

		TEST_EQUAL(g_sent_packets.size(), 1);
		if (g_sent_packets.empty()) break;
		TEST_EQUAL(g_sent_packets.front().first, initial_node);

		lazy_from_entry(g_sent_packets.front().second, response);
		ret = verify_message(response, get_peers_desc, get_peers_keys, error_string
			, sizeof(error_string));
		if (ret)
		{
			TEST_EQUAL(get_peers_keys[0].string_value(), "q");
			TEST_EQUAL(get_peers_keys[2].string_value(), "get_peers");
			TEST_EQUAL(get_peers_keys[5].string_value(), target.to_string());
			if (get_peers_keys[0].string_value() != "q" || get_peers_keys[2].string_value() != "get_peers") break;
		}
		else
		{
			std::fprintf(stderr, "   invalid get_peers request: %s\n", print_entry(response).c_str());
			TEST_ERROR(error_string);
			break;
		}

		std::set<tcp::endpoint> peers[2];
		peers[0].insert(tcp::endpoint(address_v4::from_string("4.1.1.1"), 4111));
		peers[0].insert(tcp::endpoint(address_v4::from_string("4.1.1.2"), 4112));
		peers[0].insert(tcp::endpoint(address_v4::from_string("4.1.1.3"), 4113));

		udp::endpoint next_node(address_v4::from_string("5.5.5.5"), 2235);
		nodes_t nodes;
		nodes.push_back(next_node);

		g_sent_packets.clear();
		send_dht_response(node, response, initial_node
			, msg_args().nodes(nodes).token("10").port(1234).peers(peers[0]));

		TEST_EQUAL(g_sent_packets.size(), 1);
		if (g_sent_packets.empty()) break;
		TEST_EQUAL(g_sent_packets.front().first, next_node);

		lazy_from_entry(g_sent_packets.front().second, response);
		ret = verify_message(response, get_peers_desc, get_peers_keys, error_string
			, sizeof(error_string));
		if (ret)
		{
			TEST_EQUAL(get_peers_keys[0].string_value(), "q");
			TEST_EQUAL(get_peers_keys[2].string_value(), "get_peers");
			TEST_EQUAL(get_peers_keys[5].string_value(), target.to_string());
			if (get_peers_keys[0].string_value() != "q" || get_peers_keys[2].string_value() != "get_peers") break;
		}
		else
		{
			std::fprintf(stderr, "   invalid get_peers request: %s\n", print_entry(response).c_str());
			TEST_ERROR(error_string);
			break;
		}

		peers[1].insert(tcp::endpoint(address_v4::from_string("4.1.1.4"), 4114));
		peers[1].insert(tcp::endpoint(address_v4::from_string("4.1.1.5"), 4115));
		peers[1].insert(tcp::endpoint(address_v4::from_string("4.1.1.6"), 4116));

		g_sent_packets.clear();
		send_dht_response(node, response, next_node
			, msg_args().token("11").port(1234).peers(peers[1]));

		for (std::list<std::pair<udp::endpoint, entry> >::iterator i = g_sent_packets.begin()
			, end(g_sent_packets.end()); i != end; ++i)
		{
//			std::fprintf(stderr, " %s:%d: %s\n", i->first.address().to_string(ec).c_str()
//				, i->first.port(), i->second.to_string().c_str());
			TEST_EQUAL(i->second["q"].string(), "announce_peer");
		}

		g_sent_packets.clear();

		for (int i = 0; i < 2; ++i)
		{
			for (std::set<tcp::endpoint>::iterator peer = peers[i].begin(); peer != peers[i].end(); ++peer)
			{
				TEST_CHECK(std::find(g_got_peers.begin(), g_got_peers.end(), *peer) != g_got_peers.end());
			}
		}
		g_got_peers.clear();
	} while (false);

	// immutable get

	g_sent_packets.clear();
	do
	{
		dht::node node(udp::v4(), &s, sett, (node_id::min)(), &observer, cnt, nodes);

		udp::endpoint initial_node(address_v4::from_string("4.4.4.4"), 1234);
		node.m_table.add_node(initial_node);

		node.get_item(items[0].target, get_immutable_item_cb);

		TEST_EQUAL(g_sent_packets.size(), 1);
		if (g_sent_packets.empty()) break;
		TEST_EQUAL(g_sent_packets.front().first, initial_node);

		lazy_from_entry(g_sent_packets.front().second, response);
		ret = verify_message(response, get_item_desc, get_item_keys, error_string
			, sizeof(error_string));
		if (ret)
		{
			TEST_EQUAL(get_item_keys[0].string_value(), "q");
			TEST_EQUAL(get_item_keys[2].string_value(), "get");
			TEST_EQUAL(get_item_keys[5].string_value(), items[0].target.to_string());
			if (get_item_keys[0].string_value() != "q" || get_item_keys[2].string_value() != "get") break;
		}
		else
		{
			std::fprintf(stderr, "   invalid get request: %s\n", print_entry(response).c_str());
			TEST_ERROR(error_string);
			break;
		}

		g_sent_packets.clear();
		send_dht_response(node, response, initial_node
			, msg_args().token("10").port(1234).value(items[0].ent));

		TEST_CHECK(g_sent_packets.empty());
		TEST_EQUAL(g_got_items.size(), 1);
		if (g_got_items.empty()) break;

		TEST_EQUAL(g_got_items.front().value(), items[0].ent);
		g_got_items.clear();

	} while (false);

	// mutable get

	g_sent_packets.clear();
	do
	{
		dht::node node(udp::v4(), &s, sett, (node_id::min)(), &observer, cnt, nodes);

		udp::endpoint initial_node(address_v4::from_string("4.4.4.4"), 1234);
		node.m_table.add_node(initial_node);

		node.get_item(public_key, std::string(), get_mutable_item_cb);

		TEST_EQUAL(g_sent_packets.size(), 1);
		if (g_sent_packets.empty()) break;
		TEST_EQUAL(g_sent_packets.front().first, initial_node);

		lazy_from_entry(g_sent_packets.front().second, response);
		ret = verify_message(response, get_item_desc, get_item_keys, error_string
			, sizeof(error_string));
		if (ret)
		{
			TEST_EQUAL(get_item_keys[0].string_value(), "q");
			TEST_EQUAL(get_item_keys[2].string_value(), "get");
			if (get_item_keys[0].string_value() != "q" || get_item_keys[2].string_value() != "get") break;
		}
		else
		{
			std::fprintf(stderr, "   invalid get request: %s\n", print_entry(response).c_str());
			TEST_ERROR(error_string);
			break;
		}

		g_sent_packets.clear();

		itemv.second = bencode(buffer, items[0].ent);
		sign_mutable_item(itemv, empty_salt, seq, public_key, private_key, signature);
		send_dht_response(node, response, initial_node
			, msg_args()
				.token("10")
				.port(1234)
				.value(items[0].ent)
				.key(std::string(public_key, item_pk_len))
				.sig(std::string(signature, item_sig_len))
				.seq(seq));

		TEST_CHECK(g_sent_packets.empty());
		TEST_EQUAL(g_got_items.size(), 1);
		if (g_got_items.empty()) break;

		TEST_EQUAL(g_got_items.front().value(), items[0].ent);
		TEST_CHECK(memcmp(g_got_items.front().pk().data(), public_key, item_pk_len) == 0);
		TEST_CHECK(memcmp(g_got_items.front().sig().data(), signature, item_sig_len) == 0);
		TEST_EQUAL(int(g_got_items.front().seq()), seq);
		g_got_items.clear();

	} while (false);

	dht::key_desc_t put_immutable_item_desc[] = {
		{"y", bdecode_node::string_t, 1, 0},
		{"t", bdecode_node::string_t, 2, 0},
		{"q", bdecode_node::string_t, 3, 0},
		{"a", bdecode_node::dict_t, 0, key_desc_t::parse_children},
			{"id", bdecode_node::string_t, 20, 0},
			{"token", bdecode_node::string_t, 2, 0},
			{"v", bdecode_node::none_t, 0, key_desc_t::last_child},
	};

	bdecode_node put_immutable_item_keys[7];

	dht::key_desc_t put_mutable_item_desc[] = {
		{"y", bdecode_node::string_t, 1, 0},
		{"t", bdecode_node::string_t, 2, 0},
		{"q", bdecode_node::string_t, 3, 0},
		{"a", bdecode_node::dict_t, 0, key_desc_t::parse_children},
			{"id", bdecode_node::string_t, 20, 0},
			{"cas", bdecode_node::string_t, 20, key_desc_t::optional},
			{"k", bdecode_node::string_t, item_pk_len, 0},
			{"seq", bdecode_node::int_t, 0, 0},
			{"sig", bdecode_node::string_t, item_sig_len, 0},
			{"token", bdecode_node::string_t, 2, 0},
			{"v", bdecode_node::none_t, 0, key_desc_t::last_child},
	};

	bdecode_node put_mutable_item_keys[11];

	// immutable put
	g_sent_packets.clear();
	for (int loop = 0; loop < 9; loop++)
	{
		// set the branching factor to k to make this a little easier
		int old_branching = sett.search_branching;
		sett.search_branching = 8;
		dht::node node(udp::v4(), &s, sett, (node_id::min)(), &observer, cnt, nodes);
		enum { num_test_nodes = 8 };
		node_entry nodes[num_test_nodes] =
			{ node_entry(items[0].target, udp::endpoint(address_v4::from_string("1.1.1.1"), 1231))
			, node_entry(items[1].target, udp::endpoint(address_v4::from_string("2.2.2.2"), 1232))
			, node_entry(items[2].target, udp::endpoint(address_v4::from_string("3.3.3.3"), 1233))
			, node_entry(items[3].target, udp::endpoint(address_v4::from_string("4.4.4.4"), 1234))
			, node_entry(items[4].target, udp::endpoint(address_v4::from_string("5.5.5.5"), 1235))
			, node_entry(items[5].target, udp::endpoint(address_v4::from_string("6.6.6.6"), 1236))
			, node_entry(items[6].target, udp::endpoint(address_v4::from_string("7.7.7.7"), 1237))
			, node_entry(items[7].target, udp::endpoint(address_v4::from_string("8.8.8.8"), 1238)) };

		for (int i = 0; i < num_test_nodes; ++i)
			node.m_table.add_node(nodes[i]);

		entry put_data;
		put_data = "Hello world";
		std::string flat_data;
		bencode(std::back_inserter(flat_data), put_data);
		sha1_hash target = item_target_id(
			std::pair<char const*, int>(flat_data.c_str(), int(flat_data.size())));

		node.put_item(target, put_data, std::bind(&put_immutable_item_cb, _1, loop));

		TEST_EQUAL(g_sent_packets.size(), 8);
		if (g_sent_packets.size() != 8) break;

		for (int i = 0; i < 8; ++i)
		{
			std::list<std::pair<udp::endpoint, entry> >::iterator packet = find_packet(nodes[i].ep());
			TEST_CHECK(packet != g_sent_packets.end());
			if (packet == g_sent_packets.end()) continue;

			lazy_from_entry(packet->second, response);
			ret = verify_message(response, get_item_desc, get_item_keys, error_string
				, sizeof(error_string));
			if (!ret)
			{
				std::fprintf(stderr, "   invalid get request: %s\n", print_entry(response).c_str());
				TEST_ERROR(error_string);
				continue;
			}
			char t[10];
			std::snprintf(t, sizeof(t), "%02d", i);

			msg_args args;
			args.token(t).port(1234).nid(nodes[i].id).nodes(nodes_t(1, nodes[i]));
			send_dht_response(node, response, nodes[i].ep(), args);
			g_sent_packets.erase(packet);
		}

		TEST_EQUAL(g_sent_packets.size(), 8);
		if (g_sent_packets.size() != 8) break;

		itemv.second = bencode(buffer, put_data);

		for (int i = 0; i < 8; ++i)
		{
			std::list<std::pair<udp::endpoint, entry> >::iterator packet = find_packet(nodes[i].ep());
			TEST_CHECK(packet != g_sent_packets.end());
			if (packet == g_sent_packets.end()) continue;

			lazy_from_entry(packet->second, response);
			ret = verify_message(response, put_immutable_item_desc, put_immutable_item_keys
				, error_string, sizeof(error_string));
			if (ret)
			{
				TEST_EQUAL(put_immutable_item_keys[0].string_value(), "q");
				TEST_EQUAL(put_immutable_item_keys[2].string_value(), "put");
				std::pair<const char*, int>v = put_immutable_item_keys[6].data_section();
				TEST_EQUAL(std::string(v.first, v.second), flat_data);
				char t[10];
				std::snprintf(t, sizeof(t), "%02d", i);
				TEST_EQUAL(put_immutable_item_keys[5].string_value(), t);
				if (put_immutable_item_keys[0].string_value() != "q"
					|| put_immutable_item_keys[2].string_value() != "put") continue;

				if (i < loop) send_dht_response(node, response, nodes[i].ep());
			}
			else
			{
				std::fprintf(stderr, "   invalid immutable put request: %s\n", print_entry(response).c_str());
				TEST_ERROR(error_string);
				continue;
			}
		}
		sett.search_branching = old_branching;
		g_sent_packets.clear();
		g_put_item.clear();
		g_put_count = 0;

	};

	// mutable put
	g_sent_packets.clear();
	for (int loop = 0; loop < 9; loop++)
	{
		// set the branching factor to k to make this a little easier
		int old_branching = sett.search_branching;
		sett.search_branching = 8;
		dht::node node(udp::v4(), &s, sett, (node_id::min)(), &observer, cnt, nodes);
		enum { num_test_nodes = 8 };
		node_entry nodes[num_test_nodes] =
			{ node_entry(items[0].target, udp::endpoint(address_v4::from_string("1.1.1.1"), 1231))
			, node_entry(items[1].target, udp::endpoint(address_v4::from_string("2.2.2.2"), 1232))
			, node_entry(items[2].target, udp::endpoint(address_v4::from_string("3.3.3.3"), 1233))
			, node_entry(items[3].target, udp::endpoint(address_v4::from_string("4.4.4.4"), 1234))
			, node_entry(items[4].target, udp::endpoint(address_v4::from_string("5.5.5.5"), 1235))
			, node_entry(items[5].target, udp::endpoint(address_v4::from_string("6.6.6.6"), 1236))
			, node_entry(items[6].target, udp::endpoint(address_v4::from_string("7.7.7.7"), 1237))
			, node_entry(items[7].target, udp::endpoint(address_v4::from_string("8.8.8.8"), 1238)) };

		for (int i = 0; i < num_test_nodes; ++i)
			node.m_table.add_node(nodes[i]);

		g_put_item.assign(items[0].ent, empty_salt, seq, public_key, private_key);
		std::string sig(g_put_item.sig().data(), item_sig_len);
		node.put_item(public_key, std::string()
				, std::bind(&put_mutable_item_cb, _1, _2, loop)
				, put_mutable_item_data_cb);

		TEST_EQUAL(g_sent_packets.size(), 8);
		if (g_sent_packets.size() != 8) break;

		for (int i = 0; i < 8; ++i)
		{
			std::list<std::pair<udp::endpoint, entry> >::iterator packet = find_packet(nodes[i].ep());
			TEST_CHECK(packet != g_sent_packets.end());
			if (packet == g_sent_packets.end()) continue;

			lazy_from_entry(packet->second, response);
			ret = verify_message(response, get_item_desc, get_item_keys, error_string
				, sizeof(error_string));
			if (!ret)
			{
				std::fprintf(stderr, "   invalid get request: %s\n", print_entry(response).c_str());
				TEST_ERROR(error_string);
				continue;
			}
			char t[10];
			std::snprintf(t, sizeof(t), "%02d", i);

			msg_args args;
			args.token(t).port(1234).nid(nodes[i].id).nodes(nodes_t(1, nodes[i]));

			send_dht_response(node, response, nodes[i].ep(), args);
			g_sent_packets.erase(packet);
		}

		TEST_EQUAL(g_sent_packets.size(), 8);
		if (g_sent_packets.size() != 8) break;

		itemv.second = bencode(buffer, items[0].ent);

		for (int i = 0; i < 8; ++i)
		{
			std::list<std::pair<udp::endpoint, entry> >::iterator packet = find_packet(nodes[i].ep());
			TEST_CHECK(packet != g_sent_packets.end());
			if (packet == g_sent_packets.end()) continue;

			lazy_from_entry(packet->second, response);
			ret = verify_message(response, put_mutable_item_desc, put_mutable_item_keys
				, error_string, sizeof(error_string));
			if (ret)
			{
				TEST_EQUAL(put_mutable_item_keys[0].string_value(), "q");
				TEST_EQUAL(put_mutable_item_keys[2].string_value(), "put");
				TEST_EQUAL(put_mutable_item_keys[6].string_value(), std::string(public_key, item_pk_len));
				TEST_EQUAL(put_mutable_item_keys[7].int_value(), seq);
				TEST_EQUAL(put_mutable_item_keys[8].string_value(), sig);
				std::pair<const char*, int> v = put_mutable_item_keys[10].data_section();
				TEST_EQUAL(v.second, itemv.second);
				TEST_CHECK(memcmp(v.first, itemv.first, itemv.second) == 0);
				char t[10];
				std::snprintf(t, sizeof(t), "%02d", i);
				TEST_EQUAL(put_mutable_item_keys[9].string_value(), t);
				if (put_mutable_item_keys[0].string_value() != "q"
					|| put_mutable_item_keys[2].string_value() != "put") continue;

				if (i < loop) send_dht_response(node, response, nodes[i].ep());
			}
			else
			{
				std::fprintf(stderr, "   invalid put request: %s\n", print_entry(response).c_str());
				TEST_ERROR(error_string);
				continue;
			}
		}
		sett.search_branching = old_branching;
		g_sent_packets.clear();
		g_put_item.clear();
		g_put_count = 0;
	}

	// verify that done() is only invoked once
	// See PR 252
	g_sent_packets.clear();
	do
	{
		// set the branching factor to k to make this a little easier
		int old_branching = sett.search_branching;
		sett.search_branching = 8;
		dht::node node(udp::v4(), &s, sett, (node_id::min)(), &observer, cnt, nodes);
		sha1_hash target = hasher(public_key, item_pk_len).final();
		enum { num_test_nodes = 9 }; // we need K + 1 nodes to create the failing sequence
		node_entry nodes[num_test_nodes] =
			{ node_entry(target, udp::endpoint(address_v4::from_string("1.1.1.1"), 1231))
			, node_entry(target, udp::endpoint(address_v4::from_string("2.2.2.2"), 1232))
			, node_entry(target, udp::endpoint(address_v4::from_string("3.3.3.3"), 1233))
			, node_entry(target, udp::endpoint(address_v4::from_string("4.4.4.4"), 1234))
			, node_entry(target, udp::endpoint(address_v4::from_string("5.5.5.5"), 1235))
			, node_entry(target, udp::endpoint(address_v4::from_string("6.6.6.6"), 1236))
			, node_entry(target, udp::endpoint(address_v4::from_string("7.7.7.7"), 1237))
			, node_entry(target, udp::endpoint(address_v4::from_string("8.8.8.8"), 1238))
			, node_entry(target, udp::endpoint(address_v4::from_string("9.9.9.9"), 1239)) };

		// invert the ith most significant byte so that the test nodes are
		// progressivly closer to the target item
		for (int i = 0; i < num_test_nodes; ++i)
			nodes[i].id[i] = ~nodes[i].id[i];

		// add the first k nodes to the subject's routing table
		for (int i = 0; i < 8; ++i)
			node.m_table.add_node(nodes[i]);

		// kick off a mutable put request
		g_put_item.assign(items[0].ent, empty_salt, seq, public_key, private_key);
		node.put_item(public_key, std::string()
			, std::bind(&put_mutable_item_cb, _1, _2, 0)
			, put_mutable_item_data_cb);
		TEST_EQUAL(g_sent_packets.size(), 8);
		if (g_sent_packets.size() != 8) break;

		// first send responses for the k closest nodes
		for (int i = 1;; ++i)
		{
			// once the k closest nodes have responded, send the final response
			// from the farthest node, this shouldn't trigger a second call to
			// get_item_cb
			if (i == num_test_nodes) i = 0;

			std::list<std::pair<udp::endpoint, entry> >::iterator packet = find_packet(nodes[i].ep());
			TEST_CHECK(packet != g_sent_packets.end());
			if (packet == g_sent_packets.end()) continue;

			lazy_from_entry(packet->second, response);
			ret = verify_message(response, get_item_desc, get_item_keys, error_string
				, sizeof(error_string));
			if (!ret)
			{
				std::fprintf(stderr, "   invalid get request: %s\n", print_entry(response).c_str());
				TEST_ERROR(error_string);
				continue;
			}
			char t[10];
			std::snprintf(t, sizeof(t), "%02d", i);

			msg_args args;
			args.token(t).port(1234).nid(nodes[i].id);

			// add the address of the closest node to the first response
			if (i == 1)
				args.nodes(nodes_t(1, nodes[8]));

			send_dht_response(node, response, nodes[i].ep(), args);
			g_sent_packets.erase(packet);

			// once we've sent the response from the farthest node, we're done
			if (i == 0) break;
		}

		TEST_EQUAL(g_put_count, 1);
		// k nodes should now have outstanding put requests
		TEST_EQUAL(g_sent_packets.size(), 8);

		g_sent_packets.clear();
		g_put_item.clear();
		g_put_count = 0;
		sett.search_branching = old_branching;
	} while (false);
}

TORRENT_TEST(dht)
{
	do_test_dht(rand_v4);
#if TORRENT_USE_IPV6
	if (supports_ipv6())
		do_test_dht(rand_v6);
#endif
}

TORRENT_TEST(dht_dual_stack)
{
	dht_settings sett = test_settings();
	mock_socket s;
	obs observer;
	counters cnt;
	std::map<std::string, node*> nodes;
	dht::node node4(udp::v4(), &s, sett, node_id(0), &observer, cnt, nodes);
	dht::node node6(udp::v6(), &s, sett, node_id(0), &observer, cnt, nodes);
	nodes.insert(std::make_pair("n4", &node4));
	nodes.insert(std::make_pair("n6", &node6));

	// DHT should be running on port 48199 now
	bdecode_node response;
	char error_string[200];
	bool ret;

	node_id id = to_hash("3123456789abcdef01232456789abcdef0123456");
	node4.m_table.node_seen(id, udp::endpoint(address::from_string("4.4.4.4"), 4440), 10);
	node6.m_table.node_seen(id, udp::endpoint(address::from_string("4::4"), 4441), 10);

	// v4 node requesting v6 nodes

	udp::endpoint source(address::from_string("10.0.0.1"), 20);

	send_dht_request(node4, "find_node", source, &response
		, msg_args().target("0101010101010101010101010101010101010101").want("n6"));

	dht::key_desc_t nodes6_desc[] = {
		{ "y", bdecode_node::string_t, 1, 0 },
		{ "r", bdecode_node::dict_t, 0, key_desc_t::parse_children },
		{ "id", bdecode_node::string_t, 20, 0 },
		{ "nodes6", bdecode_node::string_t, 38, key_desc_t::last_child }
	};

	bdecode_node nodes6_keys[4];

	ret = verify_message(response, nodes6_desc, nodes6_keys, error_string
		, sizeof(error_string));

	if (ret)
	{
		char const* nodes_ptr = nodes6_keys[3].string_ptr();
		TEST_CHECK(memcmp(nodes_ptr, id.data(), id.size) == 0);
		nodes_ptr += id.size;
		udp::endpoint rep = detail::read_v6_endpoint<udp::endpoint>(nodes_ptr);
		TEST_EQUAL(rep, udp::endpoint(address::from_string("4::4"), 4441));
	}
	else
	{
		std::fprintf(stderr, "find_node response: %s\n", print_entry(response).c_str());
		TEST_ERROR(error_string);
	}

	// v6 node requesting v4 nodes

	source.address(address::from_string("10::1"));

	send_dht_request(node6, "get_peers", source, &response
		, msg_args().info_hash("0101010101010101010101010101010101010101").want("n4"));

	dht::key_desc_t nodes_desc[] = {
		{ "y", bdecode_node::string_t, 1, 0 },
		{ "r", bdecode_node::dict_t, 0, key_desc_t::parse_children },
		{ "id", bdecode_node::string_t, 20, 0 },
		{ "nodes", bdecode_node::string_t, 26, key_desc_t::last_child }
	};

	bdecode_node nodes_keys[4];

	ret = verify_message(response, nodes_desc, nodes_keys, error_string
		, sizeof(error_string));

	if (ret)
	{
		char const* nodes_ptr = nodes_keys[3].string_ptr();
		TEST_CHECK(memcmp(nodes_ptr, id.data(), id.size) == 0);
		nodes_ptr += id.size;
		udp::endpoint rep = detail::read_v4_endpoint<udp::endpoint>(nodes_ptr);
		TEST_EQUAL(rep, udp::endpoint(address::from_string("4.4.4.4"), 4440));
	}
	else
	{
		std::fprintf(stderr, "find_node response: %s\n", print_entry(response).c_str());
		TEST_ERROR(error_string);
	}

	// v6 node requesting both v4 and v6 nodes

	send_dht_request(node6, "find_nodes", source, &response
		, msg_args().info_hash("0101010101010101010101010101010101010101")
			.want("n4")
			.want("n6"));

	dht::key_desc_t nodes46_desc[] = {
		{ "y", bdecode_node::string_t, 1, 0 },
		{ "r", bdecode_node::dict_t, 0, key_desc_t::parse_children },
		{ "id", bdecode_node::string_t, 20, 0 },
		{ "nodes", bdecode_node::string_t, 26, 0 },
		{ "nodes6", bdecode_node::string_t, 38, key_desc_t::last_child }
	};

	bdecode_node nodes46_keys[5];

	ret = verify_message(response, nodes46_desc, nodes46_keys, error_string
		, sizeof(error_string));

	if (ret)
	{
		char const* nodes_ptr = nodes46_keys[3].string_ptr();
		TEST_CHECK(memcmp(nodes_ptr, id.data(), id.size) == 0);
		nodes_ptr += id.size;
		udp::endpoint rep = detail::read_v4_endpoint<udp::endpoint>(nodes_ptr);
		TEST_EQUAL(rep, udp::endpoint(address::from_string("4.4.4.4"), 4440));

		nodes_ptr = nodes46_keys[4].string_ptr();
		TEST_CHECK(memcmp(nodes_ptr, id.data(), id.size) == 0);
		nodes_ptr += id.size;
		rep = detail::read_v6_endpoint<udp::endpoint>(nodes_ptr);
		TEST_EQUAL(rep, udp::endpoint(address::from_string("4::4"), 4441));
	}
	else
	{
		std::fprintf(stderr, "find_node response: %s\n", print_entry(response).c_str());
		TEST_ERROR(error_string);
	}
}

void get_test_keypair(char* public_key, char* private_key)
{
	from_hex("77ff84905a91936367c01360803104f92432fcd904a43511876df5cdf3e7e548", 64, public_key);
	from_hex("e06d3183d14159228433ed599221b80bd0a5ce8352e4bdf0262f76786ef1c74d"
		"b7e7a9fea2c0eb269d61e3b38e450a22e754941ac78479d6c54e1faf6037881d", 128, private_key);
}

TORRENT_TEST(signing_test1)
{
	// test vector 1

	// test content
	std::pair<char const*, int> test_content("12:Hello World!", 15);
	// test salt
	std::pair<char const*, int> test_salt("foobar", 6);

	char private_key[item_sk_len];
	char public_key[item_pk_len];
	get_test_keypair(public_key, private_key);
	std::pair<char const*, int> empty_salt;

	char signature[item_sig_len];

	sign_mutable_item(test_content, empty_salt, 1, public_key
		, private_key, signature);

	TEST_EQUAL(to_hex(std::string(signature, 64))
		, "305ac8aeb6c9c151fa120f120ea2cfb923564e11552d06a5d856091e5e853cff"
		"1260d3f39e4999684aa92eb73ffd136e6f4f3ecbfda0ce53a1608ecd7ae21f01");

	sha1_hash target_id = item_target_id(empty_salt, public_key);
	TEST_EQUAL(to_hex(target_id.to_string()), "4a533d47ec9c7d95b1ad75f576cffc641853b750");
}

TORRENT_TEST(signing_test2)
{

	char private_key[item_sk_len];
	char public_key[item_pk_len];
	get_test_keypair(public_key, private_key);

	// test content
	std::pair<char const*, int> test_content("12:Hello World!", 15);

	char signature[item_sig_len];
	// test salt
	std::pair<char const*, int> test_salt("foobar", 6);

	// test vector 2 (the keypair is the same as test 1)
	sign_mutable_item(test_content, test_salt, 1, public_key
		, private_key, signature);

	TEST_EQUAL(to_hex(std::string(signature, 64))
		, "6834284b6b24c3204eb2fea824d82f88883a3d95e8b4a21b8c0ded553d17d17d"
		"df9a8a7104b1258f30bed3787e6cb896fca78c58f8e03b5f18f14951a87d9a08");

	sha1_hash target_id = item_target_id(test_salt, public_key);
	TEST_EQUAL(to_hex(target_id.to_string()), "411eba73b6f087ca51a3795d9c8c938d365e32c1");
}

TORRENT_TEST(signing_test3)
{
	// test vector 3

	// test content
	std::pair<char const*, int> test_content("12:Hello World!", 15);

	sha1_hash target_id = item_target_id(test_content);
	TEST_EQUAL(to_hex(target_id.to_string()), "e5f96f6f38320f0f33959cb4d3d656452117aadb");
}

// TODO: 2 split this up into smaller test cases
TORRENT_TEST(verify_message)
{
	char error_string[200];

	// test verify_message
	static const key_desc_t msg_desc[] = {
		{"A", bdecode_node::string_t, 4, 0},
		{"B", bdecode_node::dict_t, 0, key_desc_t::optional | key_desc_t::parse_children},
			{"B1", bdecode_node::string_t, 0, 0},
			{"B2", bdecode_node::string_t, 0, key_desc_t::last_child},
		{"C", bdecode_node::dict_t, 0, key_desc_t::optional | key_desc_t::parse_children},
			{"C1", bdecode_node::string_t, 0, 0},
			{"C2", bdecode_node::string_t, 0, key_desc_t::last_child},
	};

	bdecode_node msg_keys[7];

	bdecode_node ent;

	error_code ec;
	char const test_msg[] = "d1:A4:test1:Bd2:B15:test22:B25:test3ee";
	bdecode(test_msg, test_msg + sizeof(test_msg)-1, ent, ec);
	std::fprintf(stderr, "%s\n", print_entry(ent).c_str());

	bool ret = verify_message(ent, msg_desc, msg_keys, error_string
		, sizeof(error_string));
	TEST_CHECK(ret);
	TEST_CHECK(msg_keys[0]);
	if (msg_keys[0]) TEST_EQUAL(msg_keys[0].string_value(), "test");
	TEST_CHECK(msg_keys[1]);
	TEST_CHECK(msg_keys[2]);
	if (msg_keys[2]) TEST_EQUAL(msg_keys[2].string_value(), "test2");
	TEST_CHECK(msg_keys[3]);
	if (msg_keys[3]) TEST_EQUAL(msg_keys[3].string_value(), "test3");
	TEST_CHECK(!msg_keys[4]);
	TEST_CHECK(!msg_keys[5]);
	TEST_CHECK(!msg_keys[6]);

	char const test_msg2[] = "d1:A4:test1:Cd2:C15:test22:C25:test3ee";
	bdecode(test_msg2, test_msg2 + sizeof(test_msg2)-1, ent, ec);
	std::fprintf(stderr, "%s\n", print_entry(ent).c_str());

	ret = verify_message(ent, msg_desc, msg_keys, error_string
		, sizeof(error_string));
	TEST_CHECK(ret);
	TEST_CHECK(msg_keys[0]);
	if (msg_keys[0]) TEST_EQUAL(msg_keys[0].string_value(), "test");
	TEST_CHECK(!msg_keys[1]);
	TEST_CHECK(!msg_keys[2]);
	TEST_CHECK(!msg_keys[3]);
	TEST_CHECK(msg_keys[4]);
	TEST_CHECK(msg_keys[5]);
	if (msg_keys[5]) TEST_EQUAL(msg_keys[5].string_value(), "test2");
	TEST_CHECK(msg_keys[6]);
	if (msg_keys[6]) TEST_EQUAL(msg_keys[6].string_value(), "test3");


	char const test_msg3[] = "d1:Cd2:C15:test22:C25:test3ee";
	bdecode(test_msg3, test_msg3 + sizeof(test_msg3)-1, ent, ec);
	std::fprintf(stderr, "%s\n", print_entry(ent).c_str());

	ret = verify_message(ent, msg_desc, msg_keys, error_string
		, sizeof(error_string));
	TEST_CHECK(!ret);
	std::fprintf(stderr, "%s\n", error_string);
	TEST_EQUAL(error_string, std::string("missing 'A' key"));

	char const test_msg4[] = "d1:A6:foobare";
	bdecode(test_msg4, test_msg4 + sizeof(test_msg4)-1, ent, ec);
	std::fprintf(stderr, "%s\n", print_entry(ent).c_str());

	ret = verify_message(ent, msg_desc, msg_keys, error_string
		, sizeof(error_string));
	TEST_CHECK(!ret);
	std::fprintf(stderr, "%s\n", error_string);
	TEST_EQUAL(error_string, std::string("invalid value for 'A'"));

	char const test_msg5[] = "d1:A4:test1:Cd2:C15:test2ee";
	bdecode(test_msg5, test_msg5 + sizeof(test_msg5)-1, ent, ec);
	std::fprintf(stderr, "%s\n", print_entry(ent).c_str());

	ret = verify_message(ent, msg_desc, msg_keys, error_string
		, sizeof(error_string));
	TEST_CHECK(!ret);
	std::fprintf(stderr, "%s\n", error_string);
	TEST_EQUAL(error_string, std::string("missing 'C2' key"));

	// test empty strings [ { "":1 }, "" ]
	char const test_msg6[] = "ld0:i1ee0:e";
	bdecode(test_msg6, test_msg6 + sizeof(test_msg6)-1, ent, ec);
	std::fprintf(stderr, "%s\n", print_entry(ent).c_str());
	TEST_CHECK(ent.type() == bdecode_node::list_t);
	if (ent.type() == bdecode_node::list_t)
	{
		TEST_CHECK(ent.list_size() == 2);
		if (ent.list_size() == 2)
		{
			TEST_CHECK(ent.list_at(0).dict_find_int_value("") == 1);
			TEST_CHECK(ent.list_at(1).string_value() == "");
		}
	}
}

TORRENT_TEST(routing_table_uniform)
{
	// test routing table
	dht_settings sett = test_settings();
	obs observer;

	sett.extended_routing_table = false;
	node_id id = to_hash("1234876923549721020394873245098347598635");
	node_id diff = to_hash("15764f7459456a9453f8719b09547c11d5f34061");

	routing_table tbl(id, udp::v4(), 8, sett, &observer);

	// insert 256 nodes evenly distributed across the ID space.
	// we expect to fill the top 5 buckets
	for (int i = 255; i >= 0; --i)
	{
		// test a node with the same IP:port changing ID
		add_and_replace(id, diff);
		// in order to make this node-load a bit more realistic, start from
		// distant nodes and work our way in closer to the node id
		// the routing table will reject nodes that are too imbalanced (if all
		// nodes are very close to our ID and none are far away, it's
		// suspicious).
		id[0] ^= i;
		tbl.node_seen(id, rand_udp_ep(), 20 + (id[19] & 0xff));

		// restore the first byte of the node ID
		id[0] ^= i;
	}
	std::printf("num_active_buckets: %d\n", tbl.num_active_buckets());
	// number of nodes per tree level (when adding 256 evenly distributed
	// nodes):
	// 0: 128
	// 1: 64
	// 2: 32
	// 3: 16
	// 4: 8
	// i.e. no more than 5 levels
	TEST_EQUAL(tbl.num_active_buckets(), 5);

#if defined TORRENT_DHT_VERBOSE_LOGGING || defined TORRENT_DEBUG
	tbl.print_state(std::cerr);
#endif
}

TORRENT_TEST(routing_table_balance)
{
	dht_settings sett = test_settings();
	obs observer;

	sett.extended_routing_table = false;
	node_id id = to_hash("1234876923549721020394873245098347598635");

	routing_table tbl(id, udp::v4(), 8, sett, &observer);

	// insert nodes in the routing table that will force it to split
	// and make sure we don't end up with a table completely out of balance
	for (int i = 0; i < 32; ++i)
	{
		id[4] = i;
		tbl.node_seen(id, rand_udp_ep(), 20 + (id[19] & 0xff));
	}
	std::printf("num_active_buckets: %d\n", tbl.num_active_buckets());
	TEST_EQUAL(tbl.num_active_buckets(), 2);

#if defined TORRENT_DEBUG
	tbl.print_state(std::cerr);
#endif
}

TORRENT_TEST(routing_table_extended)
{
	dht_settings sett = test_settings();
	obs observer;
	sett.extended_routing_table = true;
	node_id id = to_hash("1234876923549721020394873245098347598635");
	node_id diff = to_hash("15764f7459456a9453f8719b09547c11d5f34061");

	// we can't add the nodes in straight 0,1,2,3 order. That way the routing
	// table would get unbalanced and intermediate nodes would be dropped
	std::vector<boost::uint8_t> node_id_prefix;
	node_id_prefix.reserve(256);
	for (int i = 0; i < 256; ++i) node_id_prefix.push_back(i);
	std::random_shuffle(node_id_prefix.begin(), node_id_prefix.end());

	routing_table tbl(id, udp::v4(), 8, sett, &observer);
	for (int i = 0; i < 256; ++i)
	{
		add_and_replace(id, diff);
		id[0] = node_id_prefix[i];
		tbl.node_seen(id, rand_udp_ep(), 20 + (id[19] & 0xff));
	}
	TEST_EQUAL(tbl.num_active_buckets(), 6);

#if defined TORRENT_DEBUG
	tbl.print_state(std::cerr);
#endif
}

void inserter(std::set<node_id>* nodes, node_entry const& ne)
{
	nodes->insert(nodes->begin(), ne.id);
}

TORRENT_TEST(routing_table_set_id)
{
	dht_settings sett = test_settings();
	sett.enforce_node_id = false;
	sett.extended_routing_table = false;
	obs observer;
	node_id id = to_hash("0000000000000000000000000000000000000000");

	// we can't add the nodes in straight 0,1,2,3 order. That way the routing
	// table would get unbalanced and intermediate nodes would be dropped
	std::vector<boost::uint8_t> node_id_prefix;
	node_id_prefix.reserve(256);
	for (int i = 0; i < 256; ++i) node_id_prefix.push_back(i);
	std::random_shuffle(node_id_prefix.begin(), node_id_prefix.end());
	routing_table tbl(id, udp::v4(), 8, sett, &observer);
	for (int i = 0; i < 256; ++i)
	{
		id[0] = node_id_prefix[i];
		tbl.node_seen(id, rand_udp_ep(), 20 + (id[19] & 0xff));
	}
	TEST_EQUAL(tbl.num_active_buckets(), 6);

	std::set<node_id> original_nodes;
	tbl.for_each_node(std::bind(&inserter, &original_nodes, _1));

#if defined TORRENT_DEBUG
	tbl.print_state(std::cerr);
#endif

	id = to_hash("ffffffffffffffffffffffffffffffffffffffff");

	tbl.update_node_id(id);

	TEST_CHECK(tbl.num_active_buckets() <= 4);
	std::set<node_id> remaining_nodes;
	tbl.for_each_node(std::bind(&inserter, &remaining_nodes, _1));

	std::set<node_id> intersection;
	std::set_intersection(remaining_nodes.begin(), remaining_nodes.end()
		, original_nodes.begin(), original_nodes.end()
		, std::inserter(intersection, intersection.begin()));

	// all remaining nodes also exist in the original nodes
	TEST_EQUAL(intersection.size(), remaining_nodes.size());

#if defined TORRENT_DEBUG
	tbl.print_state(std::cerr);
#endif
}


TORRENT_TEST(read_only_node)
{
	dht_settings sett = test_settings();
	sett.read_only = true;
	mock_socket s;
	obs observer;
	counters cnt;
	std::map<std::string, node*> nodes;

	dht::node node(udp::v4(), &s, sett, node_id(0), &observer, cnt, nodes);
	udp::endpoint source(address::from_string("10.0.0.1"), 20);
	bdecode_node response;
	msg_args args;

	// for incoming requests, read_only node won't response.
	send_dht_request(node, "ping", source, &response, args, "10", false);
	TEST_EQUAL(response.type(), bdecode_node::none_t);

	args.target("01010101010101010101");
	send_dht_request(node, "get", source, &response, args, "10", false);
	TEST_EQUAL(response.type(), bdecode_node::none_t);

	// also, the sender shouldn't be added to routing table.
	TEST_EQUAL(node.size().get<0>(), 0);

	// for outgoing requests, read_only node will add 'ro' key (value == 1)
	// in top-level of request.
	bdecode_node parsed[7];
	char error_string[200];
	udp::endpoint initial_node(address_v4::from_string("4.4.4.4"), 1234);
	node.m_table.add_node(initial_node);
	bdecode_node request;
	sha1_hash target = generate_next();

	node.get_item(target, get_immutable_item_cb);
	TEST_EQUAL(g_sent_packets.size(), 1);
	TEST_EQUAL(g_sent_packets.front().first, initial_node);

	dht::key_desc_t get_item_desc[] = {
		{"y", bdecode_node::string_t, 1, 0},
		{"t", bdecode_node::string_t, 2, 0},
		{"q", bdecode_node::string_t, 3, 0},
		{"ro", bdecode_node::int_t, 4, key_desc_t::optional},
		{"a", bdecode_node::dict_t, 0, key_desc_t::parse_children},
			{"id", bdecode_node::string_t, 20, 0},
			{"target", bdecode_node::string_t, 20, key_desc_t::last_child},
	};

	lazy_from_entry(g_sent_packets.front().second, request);
	bool ret = verify_message(request, get_item_desc, parsed, error_string
		, sizeof(error_string));

	TEST_CHECK(ret);
	TEST_EQUAL(parsed[3].int_value(), 1);

	// should have one node now, which is 4.4.4.4:1234
	TEST_EQUAL(node.size().get<0>(), 1);

	// now, disable read_only, try again.
	g_sent_packets.clear();
	sett.read_only = false;

	send_dht_request(node, "get", source, &response);
	// sender should be added to routing table, there are 2 nodes now.
	TEST_EQUAL(node.size().get<0>(), 2);

	g_sent_packets.clear();
	target = generate_next();
	node.get_item(target, get_immutable_item_cb);

	// since we have 2 nodes, we should have two packets.
	TEST_EQUAL(g_sent_packets.size(), 2);

	// both of them shouldn't have a 'ro' key.
	lazy_from_entry(g_sent_packets.front().second, request);
	ret = verify_message(request, get_item_desc, parsed, error_string
		, sizeof(error_string));

	TEST_CHECK(ret);
	TEST_CHECK(!parsed[3]);

	lazy_from_entry(g_sent_packets.back().second, request);
	ret = verify_message(request, get_item_desc, parsed, error_string
		, sizeof(error_string));

	TEST_CHECK(ret);
	TEST_CHECK(!parsed[3]);
}

#ifndef TORRENT_DISABLE_LOGGING
TORRENT_TEST(invalid_error_msg)
{
	dht_settings sett = test_settings();
	mock_socket s;
	obs observer;
	counters cnt;
	std::map<std::string, node*> nodes;

	dht::node node(udp::v4(), &s, sett, node_id(0), &observer, cnt, nodes);
	udp::endpoint source(address::from_string("10.0.0.1"), 20);

	entry e;
	e["y"] = "e";
	e["e"].string() = "Malformed Error";
	char msg_buf[1500];
	int size = bencode(msg_buf, e);

	bdecode_node decoded;
	error_code ec;
	bdecode(msg_buf, msg_buf + size, decoded, ec);
	if (ec) std::fprintf(stderr, "bdecode failed: %s\n", ec.message().c_str());

	dht::msg m(decoded, source);
	node.incoming(m);

	bool found = false;
	for (int i = 0; i < int(observer.m_log.size()); ++i)
	{
		if (observer.m_log[i].find("INCOMING ERROR") != std::string::npos
			&& observer.m_log[i].find("(malformed)") != std::string::npos)
			found = true;

		std::printf("%s\n", observer.m_log[i].c_str());
	}

	TEST_EQUAL(found, true);
}

TORRENT_TEST(rpc_invalid_error_msg)
{
	dht_settings sett = test_settings();
	mock_socket s;
	obs observer;
	counters cnt;
	std::map<std::string, node*> nodes;

	dht::routing_table table(node_id(), udp::v4(), 8, sett, &observer);
	dht::rpc_manager rpc(node_id(), sett, table, &s, &observer);
	dht::node node(udp::v4(), &s, sett, node_id(0), &observer, cnt, nodes);

	udp::endpoint source(address::from_string("10.0.0.1"), 20);

	// we need this to create an entry for this transaction ID, otherwise the
	// incoming message will just be dropped
	entry req;
	req["y"] = "q";
	req["q"] = "bogus_query";
	req["t"] = "\0\0\0\0";

	g_sent_packets.clear();
	boost::intrusive_ptr<traversal_algorithm> algo(new dht::traversal_algorithm(
			node, node_id()));

	observer_ptr o(new (rpc.allocate_observer()) null_observer(algo, source, node_id()));
#if defined TORRENT_DEBUG || defined TORRENT_RELEASE_ASSERTS
	o->m_in_constructor = false;
#endif
	rpc.invoke(req, source, o);

	// here's the incoming (malformed) error message
	entry err;
	err["y"] = "e";
	err["e"].string() = "Malformed Error";
	err["t"] = g_sent_packets.begin()->second["t"].string();
	char msg_buf[1500];
	int size = bencode(msg_buf, err);

	bdecode_node decoded;
	error_code ec;
	bdecode(msg_buf, msg_buf + size, decoded, ec);
	if (ec) std::fprintf(stderr, "bdecode failed: %s\n", ec.message().c_str());

	dht::msg m(decoded, source);
	node_id nid;
	rpc.incoming(m, &nid);

	bool found = false;
	for (int i = 0; i < int(observer.m_log.size()); ++i)
	{
		if (observer.m_log[i].find("reply with") != std::string::npos
			&& observer.m_log[i].find("(malformed)") != std::string::npos
			&& observer.m_log[i].find("error") != std::string::npos)
			found = true;

		std::printf("%s\n", observer.m_log[i].c_str());
	}

	TEST_EQUAL(found, true);
}
#endif

// test bucket distribution
TORRENT_TEST(node_id_bucket_distribution)
{
	int nodes_per_bucket[160] = {0};
	dht::node_id reference_id = generate_id(rand_v4());
	int const num_samples = 100000;
	for (int i = 0; i < num_samples; ++i)
	{
		dht::node_id nid = generate_id(rand_v4());
		int const bucket = 159 - distance_exp(reference_id, nid);
		++nodes_per_bucket[bucket];
	}

	for (int i = 0; i < 25; ++i)
	{
		std::printf("%3d ", nodes_per_bucket[i]);
	}
	std::printf("\n");

	int expected = num_samples / 2;
	for (int i = 0; i < 25; ++i)
	{
		TEST_CHECK(std::abs(nodes_per_bucket[i] - expected) < num_samples / 20);
		expected /= 2;
	}
}

TORRENT_TEST(dht_verify_node_address)
{
	obs observer;
	// initial setup taken from dht test above
	dht_settings s;
	s.extended_routing_table = false;
	node_id id = to_hash("3123456789abcdef01232456789abcdef0123456");
	const int bucket_size = 10;
	dht::routing_table table(id, udp::v4(), bucket_size, s, &observer);
	std::vector<node_entry> nodes;
	TEST_EQUAL(table.size().get<0>(), 0);

	node_id tmp = id;
	node_id diff = to_hash("15764f7459456a9453f8719b09547c11d5f34061");

	add_and_replace(tmp, diff);
	table.node_seen(tmp, udp::endpoint(address::from_string("4.4.4.4"), 4), 10);
	table.find_node(id, nodes, 0, 10);
	TEST_EQUAL(table.size().get<0>(), 1);
	TEST_EQUAL(nodes.size(), 1);

	// incorrect data, wrong id
	table.node_seen(to_hash("0123456789abcdef01232456789abcdef0123456")
		, udp::endpoint(address::from_string("4.4.4.4"), 4), 10);
	table.find_node(id, nodes, 0, 10);

	TEST_EQUAL(table.size().get<0>(), 1);
	TEST_EQUAL(nodes.size(), 1);

	// incorrect data, wrong IP
	table.node_seen(tmp
		, udp::endpoint(address::from_string("4.4.4.6"), 4), 10);
	table.find_node(id, nodes, 0, 10);

	TEST_EQUAL(table.size().get<0>(), 1);
	TEST_EQUAL(nodes.size(), 1);
}

TORRENT_TEST(generate_prefix_mask)
{
	// test node-id functions
	using namespace libtorrent::dht;

	std::vector<std::pair<int, char const*>> const test = {
		{   0, "0000000000000000000000000000000000000000" },
		{   1, "8000000000000000000000000000000000000000" },
		{   2, "c000000000000000000000000000000000000000" },
		{  11, "ffe0000000000000000000000000000000000000" },
		{  17, "ffff800000000000000000000000000000000000" },
		{  37, "fffffffff8000000000000000000000000000000" },
		{ 160, "ffffffffffffffffffffffffffffffffffffffff" },
	};

	for (auto const& i : test)
	{
		TEST_EQUAL(generate_prefix_mask(i.first), to_hash(i.second));
	}
}

TORRENT_TEST(distance_exp)
{
	// distance_exp


	using tst = std::tuple<char const*, char const*, int>;

	std::vector<std::tuple<char const*, char const*, int>> const distance_tests = {
		tst{ "ffffffffffffffffffffffffffffffffffffffff"
		, "0000000000000000000000000000000000000000", 159 },

		tst{ "ffffffffffffffffffffffffffffffffffffffff"
		, "7fffffffffffffffffffffffffffffffffffffff", 159 },

		tst{ "ffffffffffffffffffffffffffffffffffffffff"
		, "ffffffffffffffffffffffffffffffffffffffff", 0 },

		tst{ "ffffffffffffffffffffffffffffffffffffffff"
		, "fffffffffffffffffffffffffffffffffffffffe", 0 },

		tst{ "8000000000000000000000000000000000000000"
		, "fffffffffffffffffffffffffffffffffffffffe", 158 },

		tst{ "c000000000000000000000000000000000000000"
		, "fffffffffffffffffffffffffffffffffffffffe", 157 },

		tst{ "e000000000000000000000000000000000000000"
		, "fffffffffffffffffffffffffffffffffffffffe", 156 },

		tst{ "f000000000000000000000000000000000000000"
		, "fffffffffffffffffffffffffffffffffffffffe", 155 },

		tst{ "f8f2340985723049587230495872304958703294"
		, "f743589043r890f023980f90e203980d090c3840", 155 },

		tst{ "ffff740985723049587230495872304958703294"
		, "ffff889043r890f023980f90e203980d090c3840", 159 - 16 },
	};

	for (auto const& t : distance_tests)
	{
		std::fprintf(stderr, "%s %s: %d\n"
			, std::get<0>(t), std::get<1>(t), std::get<2>(t));

		TEST_EQUAL(distance_exp(
				to_hash(std::get<0>(t))
				, to_hash(std::get<1>(t))
			), std::get<2>(t));
	}
}

TORRENT_TEST(compare_ip_cidr)
{
	using tst = std::tuple<char const*, char const*, bool>;
	std::vector<tst> const v4tests = {
		tst{"10.255.255.0", "10.255.255.255", true},
		tst{"11.0.0.0", "10.255.255.255", false},
		tst{"0.0.0.0", "128.255.255.255", false},
		tst{"0.0.0.0", "127.255.255.255", false},
		tst{"255.255.255.0", "255.255.255.255", true},
		tst{"255.254.255.0", "255.255.255.255", false},
		tst{"0.0.0.0", "0.0.0.0", true},
		tst{"255.255.255.255", "255.255.255.255", true},
	};

	for (auto const& t : v4tests)
	{
		std::fprintf(stderr, "%s %s\n", std::get<0>(t), std::get<1>(t));
		TEST_EQUAL(compare_ip_cidr(
			address_v4::from_string(std::get<0>(t))
			, address_v4::from_string(std::get<1>(t)))
			, std::get<2>(t));
	}

#if TORRENT_USE_IPV6
	std::vector<tst> const v6tests = {
		tst{"::1", "::ffff:ffff:ffff:ffff", true},
		tst{"::2:0000:0000:0000:0000", "::1:ffff:ffff:ffff:ffff", false},
		tst{"::ff:0000:0000:0000:0000", "::ffff:ffff:ffff:ffff", false},
		tst{"::caca:0000:0000:0000:0000", "::ffff:ffff:ffff:ffff:ffff", false},
		tst{"::a:0000:0000:0000:0000", "::b:ffff:ffff:ffff:ffff", false},
		tst{"::7f:0000:0000:0000:0000", "::ffff:ffff:ffff:ffff", false},
		tst{"7f::", "ff::", false},
		tst{"ff::", "ff::", true},
		tst{"::", "::", true},
		tst{"ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff", "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff", true},
	};

	for (auto const& t : v6tests)
	{
		TEST_EQUAL(compare_ip_cidr(
			address_v6::from_string(std::get<0>(t))
			, address_v6::from_string(std::get<1>(t)))
			, std::get<2>(t));
	}
#endif
}

#endif