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/* <!-- copyright */
/*
* aria2 - The high speed download utility
*
* Copyright (C) 2006 Tatsuhiro Tsujikawa
*
* 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 2 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
*
* In addition, as a special exception, the copyright holders give
* permission to link the code of portions of this program with the
* OpenSSL library under certain conditions as described in each
* individual source file, and distribute linked combinations
* including the two.
* You must obey the GNU General Public License in all respects
* for all of the code used other than OpenSSL. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you
* do not wish to do so, delete this exception statement from your
* version. If you delete this exception statement from all source
* files in the program, then also delete it here.
*/
/* copyright --> */
#include "DHTGetPeersReplyMessage.h"
#include <cstring>
#include "DHTNode.h"
#include "DHTBucket.h"
#include "DHTRoutingTable.h"
#include "DHTMessageFactory.h"
#include "DHTMessageDispatcher.h"
#include "DHTMessageCallback.h"
#include "bittorrent_helper.h"
#include "Peer.h"
#include "util.h"
#include "a2functional.h"
namespace aria2 {
const std::string DHTGetPeersReplyMessage::GET_PEERS("get_peers");
const std::string DHTGetPeersReplyMessage::TOKEN("token");
const std::string DHTGetPeersReplyMessage::VALUES("values");
const std::string DHTGetPeersReplyMessage::NODES("nodes");
const std::string DHTGetPeersReplyMessage::NODES6("nodes6");
DHTGetPeersReplyMessage::DHTGetPeersReplyMessage(
int family, const std::shared_ptr<DHTNode>& localNode,
const std::shared_ptr<DHTNode>& remoteNode, const std::string& token,
const std::string& transactionID)
: DHTResponseMessage{localNode, remoteNode, transactionID},
family_{family},
token_{token}
{
}
void DHTGetPeersReplyMessage::doReceivedAction()
{
// Returned peers and nodes are handled in DHTPeerLookupTask.
}
std::unique_ptr<Dict> DHTGetPeersReplyMessage::getResponse()
{
auto rDict = Dict::g();
rDict->put(DHTMessage::ID, String::g(getLocalNode()->getID(), DHT_ID_LENGTH));
rDict->put(TOKEN, token_);
// TODO want parameter
if (!closestKNodes_.empty()) {
unsigned char buffer[DHTBucket::K * 38];
const int clen = bittorrent::getCompactLength(family_);
const int unit = clen + 20;
size_t offset = 0;
size_t k = 0;
for (auto i = std::begin(closestKNodes_), eoi = std::end(closestKNodes_);
i != eoi && k < DHTBucket::K; ++i) {
memcpy(buffer + offset, (*i)->getID(), DHT_ID_LENGTH);
unsigned char compact[COMPACT_LEN_IPV6];
int compactlen = bittorrent::packcompact(compact, (*i)->getIPAddress(),
(*i)->getPort());
if (compactlen == clen) {
memcpy(buffer + 20 + offset, compact, compactlen);
offset += unit;
++k;
}
}
rDict->put(family_ == AF_INET ? NODES : NODES6, String::g(buffer, offset));
}
if (!values_.empty()) {
// Limit the size of values list. The maximum size of UDP datagram
// is limited to 65535 bytes. aria2 uses 20bytes token and 2byte
// transaction ID. The size of get_peers reply message without
// values list and nodes is 87bytes:
//
// d1:rd2:id20:aaaaaaaaaaaaaaaaaaaa5:token20:aaaaaaaaaaaaaaaaaaaa
// 6:valueslee1:t2:bb1:y1:re
//
// nodes are 38 bytes per host for IPv6 and the number of hosts is
// K(=8) max. So without values list, we already 87+38*8+4 = 395.
//
// Because of Path MTU Discovery, UDP packet size which need not
// to be fragmented is much smaller. Since Linux uses Path MTU
// Discovery by default and returning ICMP message might be
// filtered, we should avoid fragmentation. MTU of pppoe is 1492
// max according to RFC2516. We use maximum packet size to be
// 1024. Since it contains 20 bytes IP header and 8 bytes UDP
// header and 395 bytes reply message template described above, We
// can carry (1024-28-395)/(18+3) = 28 peer info. Since DHT spec
// doesn't specify the maximum size of token, reply message
// template may get bigger than 395 bytes. So we use 25 as maximum
// number of peer info that a message can carry.
static const size_t MAX_VALUES_SIZE = 25;
auto valuesList = List::g();
for (auto i = std::begin(values_), eoi = std::end(values_);
i != eoi && valuesList->size() < MAX_VALUES_SIZE; ++i) {
unsigned char compact[COMPACT_LEN_IPV6];
const int clen = bittorrent::getCompactLength(family_);
int compactlen = bittorrent::packcompact(compact, (*i)->getIPAddress(),
(*i)->getPort());
if (compactlen == clen) {
valuesList->append(String::g(compact, compactlen));
}
}
rDict->put(VALUES, std::move(valuesList));
}
return rDict;
}
const std::string& DHTGetPeersReplyMessage::getMessageType() const
{
return GET_PEERS;
}
void DHTGetPeersReplyMessage::accept(DHTMessageCallback* callback)
{
callback->visit(this);
}
std::string DHTGetPeersReplyMessage::toStringOptional() const
{
return fmt("token=%s, values=%lu, nodes=%lu", util::toHex(token_).c_str(),
static_cast<unsigned long>(values_.size()),
static_cast<unsigned long>(closestKNodes_.size()));
}
void DHTGetPeersReplyMessage::setClosestKNodes(
std::vector<std::shared_ptr<DHTNode>> closestKNodes)
{
closestKNodes_ = std::move(closestKNodes);
}
void DHTGetPeersReplyMessage::setValues(
std::vector<std::shared_ptr<Peer>> peers)
{
values_ = std::move(peers);
}
} // namespace aria2
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