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opendht/src/network_engine.cpp
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/*
* Copyright (C) 2014-2016 Savoir-faire Linux Inc.
* Author(s) : Adrien Béraud <adrien.beraud@savoirfairelinux.com>
* Simon Désaulniers <sim.desaulniers@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "network_engine.h"
#include "request.h"
#include <msgpack.hpp>
namespace dht {
const std::string DhtProtocolException::GET_NO_INFOHASH {"Get_values with no info_hash"};
const std::string DhtProtocolException::LISTEN_NO_INFOHASH {"Listen with no info_hash"};
const std::string DhtProtocolException::LISTEN_WRONG_TOKEN {"Listen with wrong token"};
const std::string DhtProtocolException::PUT_NO_INFOHASH {"Put with no info_hash"};
const std::string DhtProtocolException::PUT_WRONG_TOKEN {"Put with wrong token"};
const std::string DhtProtocolException::PUT_INVALID_ID {"Put with invalid id"};
constexpr std::chrono::seconds NetworkEngine::UDP_REPLY_TIME;
const std::string NetworkEngine::my_v {"RNG1"};
const constexpr uint16_t NetworkEngine::TransId::INVALID;
std::mt19937 NetworkEngine::rd_device {dht::crypto::random_device{}()};
const NetworkEngine::TransPrefix NetworkEngine::TransPrefix::PING = {"pn"};
const NetworkEngine::TransPrefix NetworkEngine::TransPrefix::FIND_NODE = {"fn"};
const NetworkEngine::TransPrefix NetworkEngine::TransPrefix::GET_VALUES = {"gt"};
const NetworkEngine::TransPrefix NetworkEngine::TransPrefix::ANNOUNCE_VALUES = {"pt"};
const NetworkEngine::TransPrefix NetworkEngine::TransPrefix::LISTEN = {"lt"};
constexpr long unsigned NetworkEngine::MAX_REQUESTS_PER_SEC;
static const uint8_t v4prefix[16] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0, 0, 0, 0
};
enum class MessageType {
Error = 0,
Reply,
Ping,
FindNode,
GetValues,
AnnounceValue,
Listen
};
struct ParsedMessage {
MessageType type;
InfoHash id; /* the id of the sender */
InfoHash info_hash; /* hash for which values are requested */
InfoHash target; /* target id around which to find nodes */
NetworkEngine::TransId tid; /* transaction id */
Blob token; /* security token */
Value::Id value_id; /* the value id */
time_point created { time_point::max() }; /* time when value was first created */
Blob nodes4_raw, nodes6_raw; /* IPv4 nodes in response to a 'find' request */
std::vector<std::shared_ptr<Node>> nodes4, nodes6;
std::vector<std::shared_ptr<Value>> values; /* values for a 'get' request */
want_t want; /* states if ipv4 or ipv6 request */
uint16_t error_code; /* error code in case of error */
std::string ua;
Address addr; /* reported address by the distant node */
void msgpack_unpack(msgpack::object o);
};
NetworkEngine::RequestAnswer::RequestAnswer(ParsedMessage&& msg)
: ntoken(std::move(msg.token)), values(std::move(msg.values)), nodes4(std::move(msg.nodes4)), nodes6(std::move(msg.nodes6)) {}
void
NetworkEngine::tellListener(std::shared_ptr<Node> node, uint16_t rid, InfoHash hash, want_t want,
Blob ntoken, std::vector<std::shared_ptr<Node>> nodes, std::vector<std::shared_ptr<Node>> nodes6,
std::vector<std::shared_ptr<Value>> values)
{
auto nnodes = bufferNodes(node->getFamily(), hash, want, nodes, nodes6);
try {
sendNodesValues((const sockaddr*)&node->ss, node->sslen, TransId {TransPrefix::GET_VALUES, (uint16_t)rid}, nnodes.first, nnodes.second,
values, ntoken);
} catch (const std::overflow_error& e) {
DHT_LOG.ERROR("Can't send value: buffer not large enough !");
}
}
bool
NetworkEngine::isRunning(sa_family_t af) const
{
switch (af) {
case 0:
return dht_socket >= 0 || dht_socket6 >= 0;
case AF_INET:
return dht_socket >= 0;
case AF_INET6:
return dht_socket6 >= 0;
default:
return false;
}
}
void
NetworkEngine::cancelRequest(std::shared_ptr<Request>& req)
{
if (req) {
req->cancel();
requests.erase(req->tid);
}
}
void
NetworkEngine::clear()
{
for (auto& req : requests)
req.second->cancel();
requests.clear();
}
void
NetworkEngine::connectivityChanged()
{
cache.clearBadNodes();
}
void
NetworkEngine::requestStep(std::shared_ptr<Request> req)
{
if (not req->pending()) {
if (req->cancelled())
requests.erase(req->tid);
return;
}
auto now = scheduler.time();
if (req->isExpired(now)) {
req->node->setExpired();
requests.erase(req->tid);
return;
} else if (req->attempt_count == 1) {
req->on_expired(*req, false);
}
send((char*)req->msg.data(), req->msg.size(),
(req->node->reply_time >= now - UDP_REPLY_TIME) ? 0 : MSG_CONFIRM,
(sockaddr*)&req->node->ss, req->node->sslen);
++req->attempt_count;
req->last_try = now;
std::weak_ptr<Request> wreq = req;
scheduler.add(req->last_try + Node::MAX_RESPONSE_TIME, [this,wreq]() {
if (auto req = wreq.lock()) {
requestStep(req);
}
});
}
/**
* Sends a request to a node. Request::MAX_ATTEMPT_COUNT attempts will
* be made before the request expires.
*/
void
NetworkEngine::sendRequest(std::shared_ptr<Request>& request)
{
request->start = scheduler.time();
auto e = requests.emplace(request->tid, request);
if (!e.second) {
DHT_LOG.ERROR("Request already existed !");
}
request->node->requested(request);
requestStep(request);
}
/* Rate control for requests we receive. */
bool
NetworkEngine::rateLimit()
{
using namespace std::chrono;
const auto& now = scheduler.time();
while (not rate_limit_time.empty() and duration_cast<seconds>(now - rate_limit_time.front()) > seconds(1))
rate_limit_time.pop();
if (rate_limit_time.size() >= MAX_REQUESTS_PER_SEC)
return false;
rate_limit_time.emplace(now);
return true;
}
bool
NetworkEngine::isMartian(const sockaddr* sa, socklen_t len)
{
// Check that sa_family can be accessed safely
if (!sa || len < sizeof(sockaddr_in))
return true;
switch(sa->sa_family) {
case AF_INET: {
sockaddr_in *sin = (sockaddr_in*)sa;
const uint8_t *address = (const uint8_t*)&sin->sin_addr;
return sin->sin_port == 0 ||
(address[0] == 0) ||
(address[0] == 127) ||
((address[0] & 0xE0) == 0xE0);
}
case AF_INET6: {
if (len < sizeof(sockaddr_in6))
return true;
sockaddr_in6 *sin6 = (sockaddr_in6*)sa;
const uint8_t *address = (const uint8_t*)&sin6->sin6_addr;
return sin6->sin6_port == 0 ||
(address[0] == 0xFF) ||
(address[0] == 0xFE && (address[1] & 0xC0) == 0x80) ||
(memcmp(address, zeroes.data(), 15) == 0 &&
(address[15] == 0 || address[15] == 1)) ||
(memcmp(address, v4prefix, 12) == 0);
}
default:
return true;
}
}
/* The internal blacklist is an LRU cache of nodes that have sent
incorrect messages. */
void
NetworkEngine::blacklistNode(const std::shared_ptr<Node>& n)
{
n->setExpired();
for (auto rit = requests.begin(); rit != requests.end();) {
if (rit->second->node == n) {
//rit->second->cancel();
requests.erase(rit++);
} else {
++rit;
}
}
memcpy(&blacklist[next_blacklisted], &n->ss, n->sslen);
next_blacklisted = (next_blacklisted + 1) % BLACKLISTED_MAX;
}
bool
NetworkEngine::isNodeBlacklisted(const sockaddr *sa, socklen_t salen) const
{
if (salen > sizeof(sockaddr_storage))
return true;
/*if (isBlacklisted(sa, salen))
return true;*/
for (unsigned i = 0; i < BLACKLISTED_MAX; i++) {
if (memcmp(&blacklist[i], sa, salen) == 0)
return true;
}
return false;
}
void
NetworkEngine::processMessage(const uint8_t *buf, size_t buflen, const sockaddr* from, socklen_t fromlen)
{
if (isMartian(from, fromlen))
return;
if (isNodeBlacklisted(from, fromlen)) {
DHT_LOG.DEBUG("Received packet from blacklisted node.");
return;
}
ParsedMessage msg;
try {
msgpack::unpacked msg_res = msgpack::unpack((const char*)buf, buflen);
msg.msgpack_unpack(msg_res.get());
if (msg.type != MessageType::Error && msg.id == zeroes)
throw DhtException("no or invalid InfoHash");
} catch (const std::exception& e) {
DHT_LOG.WARN("Can't process message of size %lu: %s.", buflen, e.what());
DHT_LOG.DEBUG.logPrintable(buf, buflen);
return;
}
if (msg.id == myid || msg.id == zeroes) {
DHT_LOG.DEBUG("Received message from self.");
return;
}
if (msg.type > MessageType::Reply) {
/* Rate limit requests. */
if (!rateLimit()) {
DHT_LOG.WARN("Dropping request due to rate limiting.");
return;
}
}
const auto& now = scheduler.time();
if (msg.tid.length != 4) {
DHT_LOG.ERROR("Broken node truncates transaction ids (len: %d): ", msg.tid.length);
DHT_LOG.ERROR.logPrintable(buf, buflen);
blacklistNode(cache.getNode(msg.id, from, fromlen, now, 1));
return;
}
uint16_t ttid = 0;
if (msg.type == MessageType::Error or msg.type == MessageType::Reply) {
auto reqp = requests.find(msg.tid.getTid());
if (reqp == requests.end()) {
throw DhtProtocolException {DhtProtocolException::UNKNOWN_TID, "Can't find transaction", msg.id};
}
auto req = reqp->second;
auto node = req->node;
if (node->id != msg.id) {
bool unknown_node = node->id == zeroes;
node = cache.getNode(msg.id, from, fromlen, now, 2);
if (unknown_node) {
// received reply to a message sent when we didn't know the node ID.
req->node = node;
} else {
// received reply from unexpected node
node->received(now, req);
onNewNode(node, 2);
return;
}
} else
node->update(from, fromlen);
node->received(now, req);
onNewNode(node, 2);
onReportedAddr(msg.id, (sockaddr*)&msg.addr.first, msg.addr.second);
if (req->cancelled() or req->expired() or (req->completed() and not req->persistent)) {
requests.erase(reqp);
return;
}
switch (msg.type) {
case MessageType::Error: {
if (msg.error_code == DhtProtocolException::UNAUTHORIZED
&& msg.id != zeroes
&& (msg.tid.matches(TransPrefix::ANNOUNCE_VALUES, &ttid)
|| msg.tid.matches(TransPrefix::LISTEN, &ttid)))
{
req->last_try = TIME_INVALID;
req->reply_time = TIME_INVALID;
onError(req, DhtProtocolException {DhtProtocolException::UNAUTHORIZED});
} else {
DHT_LOG.WARN("[node %s %s] received unknown error message %u",
msg.id.toString().c_str(), print_addr(from, fromlen).c_str(), msg.error_code);
DHT_LOG.WARN.logPrintable(buf, buflen);
}
break;
}
case MessageType::Reply:
// erase before calling callback to make sure iterator is still valid
if (not req->persistent)
requests.erase(reqp);
req->reply_time = scheduler.time();
deserializeNodesValues(msg);
req->setDone(std::move(msg));
break;
default:
break;
}
} else {
auto node = cache.getNode(msg.id, from, fromlen, now, 1);
node->received(now, {});
onNewNode(node, 1);
try {
switch (msg.type) {
case MessageType::Ping:
++in_stats.ping;
DHT_LOG.DEBUG("Sending pong.");
onPing(node);
sendPong(from, fromlen, msg.tid);
break;
case MessageType::FindNode: {
DHT_LOG.DEBUG("[node %s %s] got 'find' request (%d).",
msg.id.toString().c_str(), print_addr(from, fromlen).c_str(), msg.want);
++in_stats.find;
RequestAnswer answer = onFindNode(node, msg.target, msg.want);
auto nnodes = bufferNodes(from->sa_family, msg.target, msg.want, answer.nodes4, answer.nodes6);
sendNodesValues(from, fromlen, msg.tid, nnodes.first, nnodes.second, {}, answer.ntoken);
break;
}
case MessageType::GetValues: {
DHT_LOG.DEBUG("[node %s %s] got 'get' request for %s.",
msg.id.toString().c_str(), print_addr(from, fromlen).c_str(), msg.info_hash.toString().c_str());
++in_stats.get;
RequestAnswer answer = onGetValues(node, msg.info_hash, msg.want);
auto nnodes = bufferNodes(from->sa_family, msg.info_hash, msg.want, answer.nodes4, answer.nodes6);
sendNodesValues(from, fromlen, msg.tid, nnodes.first, nnodes.second, answer.values, answer.ntoken);
break;
}
case MessageType::AnnounceValue: {
DHT_LOG.DEBUG("[node %s %s] got 'put' request for %s.",
msg.id.toString().c_str(), print_addr(from, fromlen).c_str(),
msg.info_hash.toString().c_str());
++in_stats.put;
onAnnounce(node, msg.info_hash, msg.token, msg.values, msg.created);
/* Note that if storageStore failed, we lie to the requestor.
This is to prevent them from backtracking, and hence
polluting the DHT. */
for (auto& v : msg.values) {
sendValueAnnounced(from, fromlen, msg.tid, v->id);
}
break;
}
case MessageType::Listen: {
DHT_LOG.DEBUG("[node %s %s] got 'listen' request for %s.",
msg.id.toString().c_str(), print_addr(from, fromlen).c_str(), msg.info_hash.toString().c_str());
++in_stats.listen;
RequestAnswer answer = onListen(node, msg.info_hash, msg.token, msg.tid.getTid());
sendListenConfirmation(from, fromlen, msg.tid);
break;
}
default:
break;
}
} catch (const std::overflow_error& e) {
DHT_LOG.ERROR("Can't send value: buffer not large enough !");
} catch (DhtProtocolException& e) {
sendError(from, fromlen, msg.tid, e.getCode(), e.getMsg().c_str(), true);
}
}
}
void
packToken(msgpack::packer<msgpack::sbuffer>& pk, Blob token)
{
pk.pack_bin(token.size());
pk.pack_bin_body((char*)token.data(), token.size());
}
void
insertAddr(msgpack::packer<msgpack::sbuffer>& pk, const sockaddr *sa, socklen_t)
{
size_t addr_len = (sa->sa_family == AF_INET) ? sizeof(in_addr) : sizeof(in6_addr);
void* addr_ptr = (sa->sa_family == AF_INET) ? (void*)&((sockaddr_in*)sa)->sin_addr
: (void*)&((sockaddr_in6*)sa)->sin6_addr;
pk.pack("sa");
pk.pack_bin(addr_len);
pk.pack_bin_body((char*)addr_ptr, addr_len);
}
int
NetworkEngine::send(const char *buf, size_t len, int flags, const sockaddr *sa, socklen_t salen)
{
if (salen == 0)
return -1;
int s;
if (sa->sa_family == AF_INET)
s = dht_socket;
else if (sa->sa_family == AF_INET6)
s = dht_socket6;
else
s = -1;
if (s < 0)
return -1;
return sendto(s, buf, len, flags, sa, salen);
}
std::shared_ptr<Request>
NetworkEngine::sendPing(std::shared_ptr<Node> node, RequestCb on_done, RequestExpiredCb on_expired) {
auto tid = TransId {TransPrefix::PING, getNewTid()};
msgpack::sbuffer buffer;
msgpack::packer<msgpack::sbuffer> pk(&buffer);
pk.pack_map(5);
pk.pack(std::string("a")); pk.pack_map(1);
pk.pack(std::string("id")); pk.pack(myid);
pk.pack(std::string("q")); pk.pack(std::string("ping"));
pk.pack(std::string("t")); pk.pack_bin(tid.size());
pk.pack_bin_body((const char*)tid.data(), tid.size());
pk.pack(std::string("y")); pk.pack(std::string("q"));
pk.pack(std::string("v")); pk.pack(my_v);
Blob b {buffer.data(), buffer.data() + buffer.size()};
std::shared_ptr<Request> req(new Request {tid.getTid(), node, std::move(b),
[=](const Request& req_status, ParsedMessage&&) {
DHT_LOG.DEBUG("Got pong from %s", req_status.node->toString().c_str());
if (on_done) {
on_done(req_status, {});
}
},
[=](const Request& req_status, bool) { /* on expired */
if (on_expired) {
on_expired(req_status, {});
}
}
});
sendRequest(req);
++out_stats.ping;
return req;
}
void
NetworkEngine::sendPong(const sockaddr* sa, socklen_t salen, TransId tid) {
msgpack::sbuffer buffer;
msgpack::packer<msgpack::sbuffer> pk(&buffer);
pk.pack_map(4);
pk.pack(std::string("r")); pk.pack_map(2);
pk.pack(std::string("id")); pk.pack(myid);
insertAddr(pk, sa, salen);
pk.pack(std::string("t")); pk.pack_bin(tid.size());
pk.pack_bin_body((const char*)tid.data(), tid.size());
pk.pack(std::string("y")); pk.pack(std::string("r"));
pk.pack(std::string("v")); pk.pack(my_v);
send(buffer.data(), buffer.size(), 0, sa, salen);
}
std::shared_ptr<Request>
NetworkEngine::sendFindNode(std::shared_ptr<Node> n, const InfoHash& target, want_t want,
RequestCb on_done, RequestExpiredCb on_expired) {
auto tid = TransId {TransPrefix::FIND_NODE, getNewTid()};
msgpack::sbuffer buffer;
msgpack::packer<msgpack::sbuffer> pk(&buffer);
pk.pack_map(5);
pk.pack(std::string("a")); pk.pack_map(2 + (want>0?1:0));
pk.pack(std::string("id")); pk.pack(myid);
pk.pack(std::string("target")); pk.pack(target);
if (want > 0) {
pk.pack(std::string("w"));
pk.pack_array(((want & WANT4)?1:0) + ((want & WANT6)?1:0));
if (want & WANT4) pk.pack(AF_INET);
if (want & WANT6) pk.pack(AF_INET6);
}
pk.pack(std::string("q")); pk.pack(std::string("find"));
pk.pack(std::string("t")); pk.pack_bin(tid.size());
pk.pack_bin_body((const char*)tid.data(), tid.size());
pk.pack(std::string("y")); pk.pack(std::string("q"));
pk.pack(std::string("v")); pk.pack(my_v);
Blob b {buffer.data(), buffer.data() + buffer.size()};
std::shared_ptr<Request> req(new Request {tid.getTid(), n, std::move(b),
[=](const Request& req_status, ParsedMessage&& msg) { /* on done */
if (on_done) {
on_done(req_status, {std::forward<ParsedMessage>(msg)});
}
},
[=](const Request& req_status, bool) { /* on expired */
if (on_expired) {
on_expired(req_status, {});
}
}
});
sendRequest(req);
++out_stats.find;
return req;
}
std::shared_ptr<Request>
NetworkEngine::sendGetValues(std::shared_ptr<Node> n, const InfoHash& info_hash, want_t want,
RequestCb on_done, RequestExpiredCb on_expired) {
auto tid = TransId {TransPrefix::GET_VALUES, getNewTid()};
msgpack::sbuffer buffer;
msgpack::packer<msgpack::sbuffer> pk(&buffer);
pk.pack_map(5);
pk.pack(std::string("a")); pk.pack_map(2 + (want>0?1:0));
pk.pack(std::string("id")); pk.pack(myid);
pk.pack(std::string("h")); pk.pack(info_hash);
if (want > 0) {
pk.pack(std::string("w"));
pk.pack_array(((want & WANT4)?1:0) + ((want & WANT6)?1:0));
if (want & WANT4) pk.pack(AF_INET);
if (want & WANT6) pk.pack(AF_INET6);
}
pk.pack(std::string("q")); pk.pack(std::string("get"));
pk.pack(std::string("t")); pk.pack_bin(tid.size());
pk.pack_bin_body((const char*)tid.data(), tid.size());
pk.pack(std::string("y")); pk.pack(std::string("q"));
pk.pack(std::string("v")); pk.pack(my_v);
Blob b {buffer.data(), buffer.data() + buffer.size()};
std::shared_ptr<Request> req(new Request {tid.getTid(), n, std::move(b),
[=](const Request& req_status, ParsedMessage&& msg) { /* on done */
if (on_done) {
on_done(req_status, {std::forward<ParsedMessage>(msg)});
}
},
[=](const Request& req_status, bool) { /* on expired */
if (on_expired) {
on_expired(req_status, {});
}
}
});
sendRequest(req);
++out_stats.get;
return req;
}
void
NetworkEngine::deserializeNodesValues(ParsedMessage& msg) {
if (msg.nodes4_raw.size() % NODE4_INFO_BUF_LEN != 0 || msg.nodes6_raw.size() % NODE6_INFO_BUF_LEN != 0) {
throw DhtProtocolException {DhtProtocolException::WRONG_NODE_INFO_BUF_LEN};
} else {
// deserialize nodes
const auto& now = scheduler.time();
for (unsigned i = 0; i < msg.nodes4_raw.size() / NODE4_INFO_BUF_LEN; i++) {
uint8_t *ni = msg.nodes4_raw.data() + i * NODE4_INFO_BUF_LEN;
const InfoHash& ni_id = *reinterpret_cast<InfoHash*>(ni);
if (ni_id == myid)
continue;
sockaddr_in sin;
std::fill_n((uint8_t*)&sin, sizeof(sockaddr_in), 0);
sin.sin_family = AF_INET;
memcpy(&sin.sin_addr, ni + ni_id.size(), 4);
memcpy(&sin.sin_port, ni + ni_id.size() + 4, 2);
if (isMartian((sockaddr*)&sin, sizeof(sin)) || isNodeBlacklisted((sockaddr*)&sin, sizeof(sin)))
continue;
msg.nodes4.emplace_back(cache.getNode(ni_id, (sockaddr*)&sin, sizeof(sin), now, 0));
onNewNode(msg.nodes4.back(), 0);
}
for (unsigned i = 0; i < msg.nodes6_raw.size() / NODE6_INFO_BUF_LEN; i++) {
uint8_t *ni = msg.nodes6_raw.data() + i * NODE6_INFO_BUF_LEN;
const InfoHash& ni_id = *reinterpret_cast<InfoHash*>(ni);
if (ni_id == myid)
continue;
sockaddr_in6 sin6;
std::fill_n((uint8_t*)&sin6, sizeof(sockaddr_in6), 0);
sin6.sin6_family = AF_INET6;
memcpy(&sin6.sin6_addr, ni + HASH_LEN, 16);
memcpy(&sin6.sin6_port, ni + HASH_LEN + 16, 2);
if (isMartian((sockaddr*)&sin6, sizeof(sin6)) || isNodeBlacklisted((sockaddr*)&sin6, sizeof(sin6)))
continue;
msg.nodes6.emplace_back(cache.getNode(ni_id, (sockaddr*)&sin6, sizeof(sin6), now, 0));
onNewNode(msg.nodes6.back(), 0);
}
}
}
void
NetworkEngine::sendNodesValues(const sockaddr* sa, socklen_t salen, TransId tid, const Blob& nodes, const Blob& nodes6,
const std::vector<std::shared_ptr<Value>>& st, const Blob& token) {
msgpack::sbuffer buffer;
msgpack::packer<msgpack::sbuffer> pk(&buffer);
pk.pack_map(4);
pk.pack(std::string("r"));
pk.pack_map(2 + (not st.empty()?1:0) + (nodes.size()>0?1:0) + (nodes6.size()>0?1:0) + (not token.empty()?1:0));
pk.pack(std::string("id")); pk.pack(myid);
insertAddr(pk, sa, salen);
if (nodes.size() > 0) {
pk.pack(std::string("n4"));
pk.pack_bin(nodes.size());
pk.pack_bin_body((const char*)nodes.data(), nodes.size());
}
if (nodes6.size() > 0) {
pk.pack(std::string("n6"));
pk.pack_bin(nodes6.size());
pk.pack_bin_body((const char*)nodes6.data(), nodes6.size());
}
if (not token.empty()) {
pk.pack(std::string("token")); packToken(pk, token);
}
if (not st.empty()) {
// We treat the storage as a circular list, and serve a randomly
// chosen slice. In order to make sure we fit,
// we limit ourselves to 50 values.
std::uniform_int_distribution<> pos_dis(0, st.size()-1);
std::vector<Blob> subset {};
subset.reserve(std::min<size_t>(st.size(), 50));
size_t total_size = 0;
unsigned j0 = pos_dis(rd_device);
unsigned j = j0;
unsigned k = 0;
do {
subset.emplace_back(packMsg(st[j]));
total_size += subset.back().size();
++k;
j = (j + 1) % st.size();
} while (j != j0 && k < 50 && total_size < MAX_VALUE_SIZE);
pk.pack(std::string("values"));
pk.pack_array(subset.size());
for (const auto& b : subset)
buffer.write((const char*)b.data(), b.size());
DHT_LOG.DEBUG("sending closest nodes (%d+%d nodes.), %lu bytes of values", nodes.size(), nodes6.size(), total_size);
} else
DHT_LOG.DEBUG("sending closest nodes (%d+%d nodes.)", nodes.size(), nodes6.size());
pk.pack(std::string("t")); pk.pack_bin(tid.size());
pk.pack_bin_body((const char*)tid.data(), tid.size());
pk.pack(std::string("y")); pk.pack(std::string("r"));
pk.pack(std::string("v")); pk.pack(my_v);
send(buffer.data(), buffer.size(), 0, sa, salen);
}
Blob
NetworkEngine::bufferNodes(sa_family_t af, const InfoHash& id, std::vector<std::shared_ptr<Node>>& nodes)
{
std::sort(nodes.begin(), nodes.end(), [&](const std::shared_ptr<Node>& a, const std::shared_ptr<Node>& b){
return id.xorCmp(a->id, b->id) < 0;
});
size_t nnode = std::min<size_t>(TARGET_NODES, nodes.size());
Blob bnodes;
if (af == AF_INET) {
bnodes.resize(NODE4_INFO_BUF_LEN * nnode);
const constexpr size_t size = HASH_LEN + sizeof(in_addr) + sizeof(in_port_t); // 26
for (size_t i=0; i<nnode; i++) {
const Node& n = *nodes[i];
sockaddr_in *sin = (sockaddr_in*)&n.ss;
auto dest = bnodes.data() + size * i;
memcpy(dest, n.id.data(), HASH_LEN);
memcpy(dest + HASH_LEN, &sin->sin_addr, sizeof(in_addr));
memcpy(dest + HASH_LEN + sizeof(in_addr), &sin->sin_port, 2);
}
} else if (af == AF_INET6) {
bnodes.resize(NODE6_INFO_BUF_LEN * nnode);
const constexpr size_t size = HASH_LEN + sizeof(in6_addr) + sizeof(in_port_t); // 38
for (size_t i=0; i<nnode; i++) {
const Node& n = *nodes[i];
sockaddr_in6 *sin6 = (sockaddr_in6*)&n.ss;
auto dest = bnodes.data() + size * i;
memcpy(dest, n.id.data(), HASH_LEN);
memcpy(dest + HASH_LEN, &sin6->sin6_addr, sizeof(in6_addr));
memcpy(dest + HASH_LEN + sizeof(in6_addr), &sin6->sin6_port, 2);
}
}
return bnodes;
}
std::pair<Blob, Blob>
NetworkEngine::bufferNodes(sa_family_t af, const InfoHash& id, want_t want,
std::vector<std::shared_ptr<Node>>& nodes4, std::vector<std::shared_ptr<Node>>& nodes6)
{
if (want < 0)
want = af == AF_INET ? WANT4 : WANT6;
Blob bnodes4;
if (want & WANT4)
bnodes4 = bufferNodes(AF_INET, id, nodes4);
Blob bnodes6;
if (want & WANT6)
bnodes6 = bufferNodes(AF_INET6, id, nodes6);
return {std::move(bnodes4), std::move(bnodes6)};
}
std::shared_ptr<Request>
NetworkEngine::sendListen(std::shared_ptr<Node> n, const InfoHash& infohash, const Blob& token,
RequestCb on_done, RequestExpiredCb on_expired) {
auto tid = TransId {TransPrefix::LISTEN, getNewTid()};
msgpack::sbuffer buffer;
msgpack::packer<msgpack::sbuffer> pk(&buffer);
pk.pack_map(5);
pk.pack(std::string("a")); pk.pack_map(3);
pk.pack(std::string("id")); pk.pack(myid);
pk.pack(std::string("h")); pk.pack(infohash);
pk.pack(std::string("token")); packToken(pk, token);
pk.pack(std::string("q")); pk.pack(std::string("listen"));
pk.pack(std::string("t")); pk.pack_bin(tid.size());
pk.pack_bin_body((const char*)tid.data(), tid.size());
pk.pack(std::string("y")); pk.pack(std::string("q"));
pk.pack(std::string("v")); pk.pack(my_v);
Blob b {buffer.data(), buffer.data() + buffer.size()};
std::shared_ptr<Request> req(new Request {tid.getTid(), n, std::move(b),
[=](const Request& req_status, ParsedMessage&& msg) { /* on done */
if (on_done)
on_done(req_status, {std::forward<ParsedMessage>(msg)});
},
[=](const Request& req_status, bool) { /* on expired */
if (on_expired)
on_expired(req_status, {});
},
true
});
sendRequest(req);
++out_stats.listen;
return req;
}
void
NetworkEngine::sendListenConfirmation(const sockaddr* sa, socklen_t salen, TransId tid) {
msgpack::sbuffer buffer;
msgpack::packer<msgpack::sbuffer> pk(&buffer);
pk.pack_map(4);
pk.pack(std::string("r")); pk.pack_map(2);
pk.pack(std::string("id")); pk.pack(myid);
insertAddr(pk, sa, salen);
pk.pack(std::string("t")); pk.pack_bin(tid.size());
pk.pack_bin_body((const char*)tid.data(), tid.size());
pk.pack(std::string("y")); pk.pack(std::string("r"));
pk.pack(std::string("v")); pk.pack(my_v);
send(buffer.data(), buffer.size(), 0, sa, salen);
}
std::shared_ptr<Request>
NetworkEngine::sendAnnounceValue(std::shared_ptr<Node> n, const InfoHash& infohash, const Value& value, time_point created,
const Blob& token, RequestCb on_done, RequestExpiredCb on_expired) {
auto tid = TransId {TransPrefix::ANNOUNCE_VALUES, getNewTid()};
msgpack::sbuffer buffer;
msgpack::packer<msgpack::sbuffer> pk(&buffer);
pk.pack_map(5);
pk.pack(std::string("a")); pk.pack_map((created < scheduler.time() ? 5 : 4));
pk.pack(std::string("id")); pk.pack(myid);
pk.pack(std::string("h")); pk.pack(infohash);
pk.pack(std::string("values")); pk.pack_array(1); pk.pack(value);
if (created < scheduler.time()) {
pk.pack(std::string("c"));
pk.pack(to_time_t(created));
}
pk.pack(std::string("token")); pk.pack(token);
pk.pack(std::string("q")); pk.pack(std::string("put"));
pk.pack(std::string("t")); pk.pack_bin(tid.size());
pk.pack_bin_body((const char*)tid.data(), tid.size());
pk.pack(std::string("y")); pk.pack(std::string("q"));
pk.pack(std::string("v")); pk.pack(my_v);
Blob b {buffer.data(), buffer.data() + buffer.size()};
std::shared_ptr<Request> req(new Request {tid.getTid(), n, std::move(b),
[=](const Request& req_status, ParsedMessage&& msg) { /* on done */
if (msg.value_id == Value::INVALID_ID) {
DHT_LOG.DEBUG("Unknown search or announce!");
} else {
if (on_done) {
RequestAnswer answer {};
answer.vid = msg.value_id;
on_done(req_status, std::move(answer));
}
}
},
[=](const Request& req_status, bool) { /* on expired */
if (on_expired) {
on_expired(req_status, {});
}
}
});
sendRequest(req);
++out_stats.put;
return req;
}
void
NetworkEngine::sendValueAnnounced(const sockaddr* sa, socklen_t salen, TransId tid, Value::Id vid) {
msgpack::sbuffer buffer;
msgpack::packer<msgpack::sbuffer> pk(&buffer);
pk.pack_map(4);
pk.pack(std::string("r")); pk.pack_map(3);
pk.pack(std::string("id")); pk.pack(myid);
pk.pack(std::string("vid")); pk.pack(vid);
insertAddr(pk, sa, salen);
pk.pack(std::string("t")); pk.pack_bin(tid.size());
pk.pack_bin_body((const char*)tid.data(), tid.size());
pk.pack(std::string("y")); pk.pack(std::string("r"));
pk.pack(std::string("v")); pk.pack(my_v);
send(buffer.data(), buffer.size(), 0, sa, salen);
}
void
NetworkEngine::sendError(const sockaddr* sa,
socklen_t salen,
TransId tid,
uint16_t code,
const std::string& message,
bool include_id) {
msgpack::sbuffer buffer;
msgpack::packer<msgpack::sbuffer> pk(&buffer);
pk.pack_map(4 + (include_id?1:0));
pk.pack(std::string("e")); pk.pack_array(2);
pk.pack(code);
pk.pack(message);
if (include_id) {
pk.pack(std::string("r")); pk.pack_map(1);
pk.pack(std::string("id")); pk.pack(myid);
}
pk.pack(std::string("t")); pk.pack_bin(tid.size());
pk.pack_bin_body((const char*)tid.data(), tid.size());
pk.pack(std::string("y")); pk.pack(std::string("e"));
pk.pack(std::string("v")); pk.pack(my_v);
send(buffer.data(), buffer.size(), 0, sa, salen);
}
msgpack::object*
findMapValue(msgpack::object& map, const std::string& key) {
if (map.type != msgpack::type::MAP) throw msgpack::type_error();
for (unsigned i = 0; i < map.via.map.size; i++) {
auto& o = map.via.map.ptr[i];
if(o.key.type != msgpack::type::STR)
continue;
if (o.key.as<std::string>() == key) {
return &o.val;
}
}
return nullptr;
}
void
ParsedMessage::msgpack_unpack(msgpack::object msg)
{
auto y = findMapValue(msg, "y");
auto a = findMapValue(msg, "a");
auto r = findMapValue(msg, "r");
auto e = findMapValue(msg, "e");
std::string query;
if (auto q = findMapValue(msg, "q")) {
if (q->type != msgpack::type::STR)
throw msgpack::type_error();
query = q->as<std::string>();
}
if (!a && !r && !e)
throw msgpack::type_error();
auto& req = a ? *a : (r ? *r : *e);
if (e) {
if (e->type != msgpack::type::ARRAY)
throw msgpack::type_error();
error_code = e->via.array.ptr[0].as<uint16_t>();
}
if (auto rid = findMapValue(req, "id"))
id = {*rid};
if (auto rh = findMapValue(req, "h"))
info_hash = {*rh};
if (auto rtarget = findMapValue(req, "target"))
target = {*rtarget};
if (auto otoken = findMapValue(req, "token"))
token = unpackBlob(*otoken);
if (auto vid = findMapValue(req, "vid"))
value_id = vid->as<Value::Id>();
if (auto rnodes4 = findMapValue(req, "n4"))
nodes4_raw = unpackBlob(*rnodes4);
if (auto rnodes6 = findMapValue(req, "n6"))
nodes6_raw = unpackBlob(*rnodes6);
if (auto sa = findMapValue(req, "sa")) {
if (sa->type != msgpack::type::BIN)
throw msgpack::type_error();
auto l = sa->via.bin.size;
if (l == sizeof(in_addr)) {
auto a = (sockaddr_in*)&addr.first;
std::fill_n((uint8_t*)a, sizeof(sockaddr_in), 0);
a->sin_family = AF_INET;
a->sin_port = 0;
std::copy_n(sa->via.bin.ptr, l, (char*)&a->sin_addr);
addr.second = sizeof(sockaddr_in);
} else if (l == sizeof(in6_addr)) {
auto a = (sockaddr_in6*)&addr.first;
std::fill_n((uint8_t*)a, sizeof(sockaddr_in6), 0);
a->sin6_family = AF_INET6;
a->sin6_port = 0;
std::copy_n(sa->via.bin.ptr, l, (char*)&a->sin6_addr);
addr.second = sizeof(sockaddr_in6);
}
} else
addr.second = 0;
if (auto rcreated = findMapValue(req, "c"))
created = from_time_t(rcreated->as<std::time_t>());
if (auto rvalues = findMapValue(req, "values")) {
if (rvalues->type != msgpack::type::ARRAY)
throw msgpack::type_error();
for (size_t i = 0; i < rvalues->via.array.size; i++)
try {
values.emplace_back(std::make_shared<Value>(rvalues->via.array.ptr[i]));
} catch (const std::exception& e) {
//DHT_LOG.WARN("Error reading value: %s", e.what());
}
}
if (auto w = findMapValue(req, "w")) {
if (w->type != msgpack::type::ARRAY)
throw msgpack::type_error();
want = 0;
for (unsigned i=0; i<w->via.array.size; i++) {
auto& val = w->via.array.ptr[i];
try {
auto w = val.as<sa_family_t>();
if (w == AF_INET)
want |= WANT4;
else if(w == AF_INET6)
want |= WANT6;
} catch (const std::exception& e) {};
}
} else {
want = -1;
}
if (auto t = findMapValue(msg, "t"))
tid = {t->as<std::array<char, 4>>()};
if (auto rv = findMapValue(msg, "v"))
ua = rv->as<std::string>();
if (e)
type = MessageType::Error;
else if (r)
type = MessageType::Reply;
else if (y and y->as<std::string>() != "q")
throw msgpack::type_error();
else if (query == "ping")
type = MessageType::Ping;
else if (query == "find")
type = MessageType::FindNode;
else if (query == "get")
type = MessageType::GetValues;
else if (query == "listen")
type = MessageType::Listen;
else if (query == "put")
type = MessageType::AnnounceValue;
else
throw msgpack::type_error();
}
}
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