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/*
* libjingle
* Copyright 2004--2005, Google Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
#include "talk/base/natsocketfactory.h"
#include "talk/base/natserver.h"
#include "talk/base/logging.h"
namespace talk_base {
RouteCmp::RouteCmp(NAT* nat) : symmetric(nat->IsSymmetric()) {
}
size_t RouteCmp::operator()(const SocketAddressPair& r) const {
size_t h = r.source().Hash();
if (symmetric)
h ^= r.destination().Hash();
return h;
}
bool RouteCmp::operator()(
const SocketAddressPair& r1, const SocketAddressPair& r2) const {
if (r1.source() < r2.source())
return true;
if (r2.source() < r1.source())
return false;
if (symmetric && (r1.destination() < r2.destination()))
return true;
if (symmetric && (r2.destination() < r1.destination()))
return false;
return false;
}
AddrCmp::AddrCmp(NAT* nat)
: use_ip(nat->FiltersIP()), use_port(nat->FiltersPort()) {
}
size_t AddrCmp::operator()(const SocketAddress& a) const {
size_t h = 0;
if (use_ip)
h ^= HashIP(a.ipaddr());
if (use_port)
h ^= a.port() | (a.port() << 16);
return h;
}
bool AddrCmp::operator()(
const SocketAddress& a1, const SocketAddress& a2) const {
if (use_ip && (a1.ipaddr() < a2.ipaddr()))
return true;
if (use_ip && (a2.ipaddr() < a1.ipaddr()))
return false;
if (use_port && (a1.port() < a2.port()))
return true;
if (use_port && (a2.port() < a1.port()))
return false;
return false;
}
NATServer::NATServer(
NATType type, SocketFactory* internal, const SocketAddress& internal_addr,
SocketFactory* external, const SocketAddress& external_ip)
: external_(external), external_ip_(external_ip.ipaddr(), 0) {
nat_ = NAT::Create(type);
server_socket_ = AsyncUDPSocket::Create(internal, internal_addr);
server_socket_->SignalReadPacket.connect(this, &NATServer::OnInternalPacket);
int_map_ = new InternalMap(RouteCmp(nat_));
ext_map_ = new ExternalMap();
}
NATServer::~NATServer() {
for (InternalMap::iterator iter = int_map_->begin();
iter != int_map_->end();
iter++)
delete iter->second;
delete nat_;
delete server_socket_;
delete int_map_;
delete ext_map_;
}
void NATServer::OnInternalPacket(
AsyncPacketSocket* socket, const char* buf, size_t size,
const SocketAddress& addr) {
// Read the intended destination from the wire.
SocketAddress dest_addr;
size_t length = UnpackAddressFromNAT(buf, size, &dest_addr);
// Find the translation for these addresses (allocating one if necessary).
SocketAddressPair route(addr, dest_addr);
InternalMap::iterator iter = int_map_->find(route);
if (iter == int_map_->end()) {
Translate(route);
iter = int_map_->find(route);
}
ASSERT(iter != int_map_->end());
// Allow the destination to send packets back to the source.
iter->second->WhitelistInsert(dest_addr);
// Send the packet to its intended destination.
iter->second->socket->SendTo(buf + length, size - length, dest_addr,
DSCP_NO_CHANGE);
}
void NATServer::OnExternalPacket(
AsyncPacketSocket* socket, const char* buf, size_t size,
const SocketAddress& remote_addr) {
SocketAddress local_addr = socket->GetLocalAddress();
// Find the translation for this addresses.
ExternalMap::iterator iter = ext_map_->find(local_addr);
ASSERT(iter != ext_map_->end());
// Allow the NAT to reject this packet.
if (ShouldFilterOut(iter->second, remote_addr)) {
LOG(LS_INFO) << "Packet from " << remote_addr.ToSensitiveString()
<< " was filtered out by the NAT.";
return;
}
// Forward this packet to the internal address.
// First prepend the address in a quasi-STUN format.
scoped_ptr<char[]> real_buf(new char[size + kNATEncodedIPv6AddressSize]);
size_t addrlength = PackAddressForNAT(real_buf.get(),
size + kNATEncodedIPv6AddressSize,
remote_addr);
// Copy the data part after the address.
std::memcpy(real_buf.get() + addrlength, buf, size);
server_socket_->SendTo(real_buf.get(), size + addrlength,
iter->second->route.source(), DSCP_NO_CHANGE);
}
void NATServer::Translate(const SocketAddressPair& route) {
AsyncUDPSocket* socket = AsyncUDPSocket::Create(external_, external_ip_);
if (!socket) {
LOG(LS_ERROR) << "Couldn't find a free port!";
return;
}
TransEntry* entry = new TransEntry(route, socket, nat_);
(*int_map_)[route] = entry;
(*ext_map_)[socket->GetLocalAddress()] = entry;
socket->SignalReadPacket.connect(this, &NATServer::OnExternalPacket);
}
bool NATServer::ShouldFilterOut(TransEntry* entry,
const SocketAddress& ext_addr) {
return entry->WhitelistContains(ext_addr);
}
NATServer::TransEntry::TransEntry(
const SocketAddressPair& r, AsyncUDPSocket* s, NAT* nat)
: route(r), socket(s) {
whitelist = new AddressSet(AddrCmp(nat));
}
NATServer::TransEntry::~TransEntry() {
delete whitelist;
delete socket;
}
void NATServer::TransEntry::WhitelistInsert(const SocketAddress& addr) {
CritScope cs(&crit_);
whitelist->insert(addr);
}
bool NATServer::TransEntry::WhitelistContains(const SocketAddress& ext_addr) {
CritScope cs(&crit_);
return whitelist->find(ext_addr) == whitelist->end();
}
} // namespace talk_base
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