524 lines
16 KiB
C++
524 lines
16 KiB
C++
/*
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* Copyright 2004 The WebRTC Project Authors. All rights reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "rtc_base/nat_socket_factory.h"
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#include "rtc_base/arraysize.h"
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#include "rtc_base/checks.h"
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#include "rtc_base/logging.h"
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#include "rtc_base/nat_server.h"
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#include "rtc_base/virtual_socket_server.h"
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namespace rtc {
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// Packs the given socketaddress into the buffer in buf, in the quasi-STUN
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// format that the natserver uses.
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// Returns 0 if an invalid address is passed.
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size_t PackAddressForNAT(char* buf,
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size_t buf_size,
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const SocketAddress& remote_addr) {
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const IPAddress& ip = remote_addr.ipaddr();
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int family = ip.family();
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buf[0] = 0;
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buf[1] = family;
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// Writes the port.
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*(reinterpret_cast<uint16_t*>(&buf[2])) = HostToNetwork16(remote_addr.port());
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if (family == AF_INET) {
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RTC_DCHECK(buf_size >= kNATEncodedIPv4AddressSize);
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in_addr v4addr = ip.ipv4_address();
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memcpy(&buf[4], &v4addr, kNATEncodedIPv4AddressSize - 4);
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return kNATEncodedIPv4AddressSize;
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} else if (family == AF_INET6) {
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RTC_DCHECK(buf_size >= kNATEncodedIPv6AddressSize);
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in6_addr v6addr = ip.ipv6_address();
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memcpy(&buf[4], &v6addr, kNATEncodedIPv6AddressSize - 4);
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return kNATEncodedIPv6AddressSize;
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}
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return 0U;
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}
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// Decodes the remote address from a packet that has been encoded with the nat's
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// quasi-STUN format. Returns the length of the address (i.e., the offset into
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// data where the original packet starts).
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size_t UnpackAddressFromNAT(const char* buf,
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size_t buf_size,
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SocketAddress* remote_addr) {
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RTC_DCHECK(buf_size >= 8);
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RTC_DCHECK(buf[0] == 0);
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int family = buf[1];
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uint16_t port =
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NetworkToHost16(*(reinterpret_cast<const uint16_t*>(&buf[2])));
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if (family == AF_INET) {
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const in_addr* v4addr = reinterpret_cast<const in_addr*>(&buf[4]);
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*remote_addr = SocketAddress(IPAddress(*v4addr), port);
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return kNATEncodedIPv4AddressSize;
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} else if (family == AF_INET6) {
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RTC_DCHECK(buf_size >= 20);
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const in6_addr* v6addr = reinterpret_cast<const in6_addr*>(&buf[4]);
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*remote_addr = SocketAddress(IPAddress(*v6addr), port);
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return kNATEncodedIPv6AddressSize;
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}
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return 0U;
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}
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// NATSocket
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class NATSocket : public AsyncSocket, public sigslot::has_slots<> {
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public:
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explicit NATSocket(NATInternalSocketFactory* sf, int family, int type)
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: sf_(sf),
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family_(family),
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type_(type),
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connected_(false),
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socket_(nullptr),
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buf_(nullptr),
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size_(0) {}
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~NATSocket() override {
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delete socket_;
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delete[] buf_;
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}
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SocketAddress GetLocalAddress() const override {
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return (socket_) ? socket_->GetLocalAddress() : SocketAddress();
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}
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SocketAddress GetRemoteAddress() const override {
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return remote_addr_; // will be NIL if not connected
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}
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int Bind(const SocketAddress& addr) override {
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if (socket_) { // already bound, bubble up error
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return -1;
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}
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return BindInternal(addr);
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}
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int Connect(const SocketAddress& addr) override {
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int result = 0;
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// If we're not already bound (meaning |socket_| is null), bind to ANY
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// address.
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if (!socket_) {
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result = BindInternal(SocketAddress(GetAnyIP(family_), 0));
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if (result < 0) {
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return result;
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}
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}
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if (type_ == SOCK_STREAM) {
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result = socket_->Connect(server_addr_.IsNil() ? addr : server_addr_);
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} else {
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connected_ = true;
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}
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if (result >= 0) {
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remote_addr_ = addr;
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}
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return result;
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}
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int Send(const void* data, size_t size) override {
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RTC_DCHECK(connected_);
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return SendTo(data, size, remote_addr_);
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}
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int SendTo(const void* data,
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size_t size,
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const SocketAddress& addr) override {
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RTC_DCHECK(!connected_ || addr == remote_addr_);
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if (server_addr_.IsNil() || type_ == SOCK_STREAM) {
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return socket_->SendTo(data, size, addr);
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}
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// This array will be too large for IPv4 packets, but only by 12 bytes.
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std::unique_ptr<char[]> buf(new char[size + kNATEncodedIPv6AddressSize]);
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size_t addrlength =
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PackAddressForNAT(buf.get(), size + kNATEncodedIPv6AddressSize, addr);
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size_t encoded_size = size + addrlength;
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memcpy(buf.get() + addrlength, data, size);
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int result = socket_->SendTo(buf.get(), encoded_size, server_addr_);
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if (result >= 0) {
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RTC_DCHECK(result == static_cast<int>(encoded_size));
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result = result - static_cast<int>(addrlength);
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}
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return result;
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}
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int Recv(void* data, size_t size, int64_t* timestamp) override {
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SocketAddress addr;
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return RecvFrom(data, size, &addr, timestamp);
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}
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int RecvFrom(void* data,
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size_t size,
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SocketAddress* out_addr,
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int64_t* timestamp) override {
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if (server_addr_.IsNil() || type_ == SOCK_STREAM) {
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return socket_->RecvFrom(data, size, out_addr, timestamp);
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}
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// Make sure we have enough room to read the requested amount plus the
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// largest possible header address.
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SocketAddress remote_addr;
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Grow(size + kNATEncodedIPv6AddressSize);
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// Read the packet from the socket.
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int result = socket_->RecvFrom(buf_, size_, &remote_addr, timestamp);
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if (result >= 0) {
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RTC_DCHECK(remote_addr == server_addr_);
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// TODO: we need better framing so we know how many bytes we can
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// return before we need to read the next address. For UDP, this will be
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// fine as long as the reader always reads everything in the packet.
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RTC_DCHECK((size_t)result < size_);
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// Decode the wire packet into the actual results.
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SocketAddress real_remote_addr;
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size_t addrlength = UnpackAddressFromNAT(buf_, result, &real_remote_addr);
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memcpy(data, buf_ + addrlength, result - addrlength);
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// Make sure this packet should be delivered before returning it.
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if (!connected_ || (real_remote_addr == remote_addr_)) {
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if (out_addr)
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*out_addr = real_remote_addr;
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result = result - static_cast<int>(addrlength);
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} else {
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RTC_LOG(LS_ERROR) << "Dropping packet from unknown remote address: "
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<< real_remote_addr.ToString();
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result = 0; // Tell the caller we didn't read anything
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}
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}
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return result;
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}
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int Close() override {
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int result = 0;
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if (socket_) {
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result = socket_->Close();
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if (result >= 0) {
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connected_ = false;
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remote_addr_ = SocketAddress();
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delete socket_;
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socket_ = nullptr;
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}
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}
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return result;
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}
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int Listen(int backlog) override { return socket_->Listen(backlog); }
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AsyncSocket* Accept(SocketAddress* paddr) override {
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return socket_->Accept(paddr);
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}
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int GetError() const override {
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return socket_ ? socket_->GetError() : error_;
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}
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void SetError(int error) override {
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if (socket_) {
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socket_->SetError(error);
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} else {
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error_ = error;
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}
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}
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ConnState GetState() const override {
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return connected_ ? CS_CONNECTED : CS_CLOSED;
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}
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int GetOption(Option opt, int* value) override {
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return socket_->GetOption(opt, value);
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}
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int SetOption(Option opt, int value) override {
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return socket_->SetOption(opt, value);
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}
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void OnConnectEvent(AsyncSocket* socket) {
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// If we're NATed, we need to send a message with the real addr to use.
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RTC_DCHECK(socket == socket_);
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if (server_addr_.IsNil()) {
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connected_ = true;
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SignalConnectEvent(this);
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} else {
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SendConnectRequest();
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}
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}
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void OnReadEvent(AsyncSocket* socket) {
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// If we're NATed, we need to process the connect reply.
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RTC_DCHECK(socket == socket_);
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if (type_ == SOCK_STREAM && !server_addr_.IsNil() && !connected_) {
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HandleConnectReply();
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} else {
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SignalReadEvent(this);
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}
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}
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void OnWriteEvent(AsyncSocket* socket) {
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RTC_DCHECK(socket == socket_);
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SignalWriteEvent(this);
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}
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void OnCloseEvent(AsyncSocket* socket, int error) {
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RTC_DCHECK(socket == socket_);
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SignalCloseEvent(this, error);
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}
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private:
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int BindInternal(const SocketAddress& addr) {
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RTC_DCHECK(!socket_);
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int result;
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socket_ = sf_->CreateInternalSocket(family_, type_, addr, &server_addr_);
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result = (socket_) ? socket_->Bind(addr) : -1;
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if (result >= 0) {
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socket_->SignalConnectEvent.connect(this, &NATSocket::OnConnectEvent);
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socket_->SignalReadEvent.connect(this, &NATSocket::OnReadEvent);
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socket_->SignalWriteEvent.connect(this, &NATSocket::OnWriteEvent);
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socket_->SignalCloseEvent.connect(this, &NATSocket::OnCloseEvent);
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} else {
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server_addr_.Clear();
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delete socket_;
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socket_ = nullptr;
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}
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return result;
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}
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// Makes sure the buffer is at least the given size.
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void Grow(size_t new_size) {
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if (size_ < new_size) {
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delete[] buf_;
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size_ = new_size;
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buf_ = new char[size_];
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}
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}
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// Sends the destination address to the server to tell it to connect.
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void SendConnectRequest() {
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char buf[kNATEncodedIPv6AddressSize];
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size_t length = PackAddressForNAT(buf, arraysize(buf), remote_addr_);
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socket_->Send(buf, length);
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}
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// Handles the byte sent back from the server and fires the appropriate event.
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void HandleConnectReply() {
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char code;
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socket_->Recv(&code, sizeof(code), nullptr);
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if (code == 0) {
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connected_ = true;
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SignalConnectEvent(this);
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} else {
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Close();
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SignalCloseEvent(this, code);
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}
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}
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NATInternalSocketFactory* sf_;
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int family_;
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int type_;
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bool connected_;
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SocketAddress remote_addr_;
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SocketAddress server_addr_; // address of the NAT server
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AsyncSocket* socket_;
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// Need to hold error in case it occurs before the socket is created.
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int error_ = 0;
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char* buf_;
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size_t size_;
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};
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// NATSocketFactory
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NATSocketFactory::NATSocketFactory(SocketFactory* factory,
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const SocketAddress& nat_udp_addr,
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const SocketAddress& nat_tcp_addr)
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: factory_(factory),
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nat_udp_addr_(nat_udp_addr),
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nat_tcp_addr_(nat_tcp_addr) {}
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Socket* NATSocketFactory::CreateSocket(int family, int type) {
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return new NATSocket(this, family, type);
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}
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AsyncSocket* NATSocketFactory::CreateAsyncSocket(int family, int type) {
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return new NATSocket(this, family, type);
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}
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AsyncSocket* NATSocketFactory::CreateInternalSocket(
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int family,
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int type,
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const SocketAddress& local_addr,
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SocketAddress* nat_addr) {
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if (type == SOCK_STREAM) {
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*nat_addr = nat_tcp_addr_;
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} else {
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*nat_addr = nat_udp_addr_;
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}
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return factory_->CreateAsyncSocket(family, type);
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}
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// NATSocketServer
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NATSocketServer::NATSocketServer(SocketServer* server)
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: server_(server), msg_queue_(nullptr) {}
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NATSocketServer::Translator* NATSocketServer::GetTranslator(
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const SocketAddress& ext_ip) {
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return nats_.Get(ext_ip);
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}
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NATSocketServer::Translator* NATSocketServer::AddTranslator(
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const SocketAddress& ext_ip,
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const SocketAddress& int_ip,
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NATType type) {
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// Fail if a translator already exists with this extternal address.
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if (nats_.Get(ext_ip))
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return nullptr;
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return nats_.Add(ext_ip, new Translator(this, type, int_ip, server_, ext_ip));
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}
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void NATSocketServer::RemoveTranslator(const SocketAddress& ext_ip) {
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nats_.Remove(ext_ip);
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}
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Socket* NATSocketServer::CreateSocket(int family, int type) {
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return new NATSocket(this, family, type);
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}
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AsyncSocket* NATSocketServer::CreateAsyncSocket(int family, int type) {
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return new NATSocket(this, family, type);
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}
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void NATSocketServer::SetMessageQueue(Thread* queue) {
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msg_queue_ = queue;
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server_->SetMessageQueue(queue);
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}
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bool NATSocketServer::Wait(int cms, bool process_io) {
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return server_->Wait(cms, process_io);
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}
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void NATSocketServer::WakeUp() {
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server_->WakeUp();
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}
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AsyncSocket* NATSocketServer::CreateInternalSocket(
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int family,
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int type,
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const SocketAddress& local_addr,
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SocketAddress* nat_addr) {
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AsyncSocket* socket = nullptr;
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Translator* nat = nats_.FindClient(local_addr);
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if (nat) {
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socket = nat->internal_factory()->CreateAsyncSocket(family, type);
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*nat_addr = (type == SOCK_STREAM) ? nat->internal_tcp_address()
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: nat->internal_udp_address();
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} else {
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socket = server_->CreateAsyncSocket(family, type);
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}
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return socket;
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}
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// NATSocketServer::Translator
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NATSocketServer::Translator::Translator(NATSocketServer* server,
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NATType type,
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const SocketAddress& int_ip,
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SocketFactory* ext_factory,
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const SocketAddress& ext_ip)
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: server_(server) {
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// Create a new private network, and a NATServer running on the private
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// network that bridges to the external network. Also tell the private
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// network to use the same message queue as us.
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VirtualSocketServer* internal_server = new VirtualSocketServer();
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internal_server->SetMessageQueue(server_->queue());
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internal_factory_.reset(internal_server);
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nat_server_.reset(new NATServer(type, internal_server, int_ip, int_ip,
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ext_factory, ext_ip));
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}
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NATSocketServer::Translator::~Translator() = default;
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NATSocketServer::Translator* NATSocketServer::Translator::GetTranslator(
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const SocketAddress& ext_ip) {
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return nats_.Get(ext_ip);
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}
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NATSocketServer::Translator* NATSocketServer::Translator::AddTranslator(
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const SocketAddress& ext_ip,
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const SocketAddress& int_ip,
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NATType type) {
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// Fail if a translator already exists with this extternal address.
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if (nats_.Get(ext_ip))
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return nullptr;
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AddClient(ext_ip);
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return nats_.Add(ext_ip,
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new Translator(server_, type, int_ip, server_, ext_ip));
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}
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void NATSocketServer::Translator::RemoveTranslator(
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const SocketAddress& ext_ip) {
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nats_.Remove(ext_ip);
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RemoveClient(ext_ip);
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}
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bool NATSocketServer::Translator::AddClient(const SocketAddress& int_ip) {
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// Fail if a client already exists with this internal address.
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if (clients_.find(int_ip) != clients_.end())
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return false;
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clients_.insert(int_ip);
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return true;
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}
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void NATSocketServer::Translator::RemoveClient(const SocketAddress& int_ip) {
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std::set<SocketAddress>::iterator it = clients_.find(int_ip);
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if (it != clients_.end()) {
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clients_.erase(it);
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}
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}
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NATSocketServer::Translator* NATSocketServer::Translator::FindClient(
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const SocketAddress& int_ip) {
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// See if we have the requested IP, or any of our children do.
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return (clients_.find(int_ip) != clients_.end()) ? this
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: nats_.FindClient(int_ip);
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}
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// NATSocketServer::TranslatorMap
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NATSocketServer::TranslatorMap::~TranslatorMap() {
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for (TranslatorMap::iterator it = begin(); it != end(); ++it) {
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delete it->second;
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}
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}
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NATSocketServer::Translator* NATSocketServer::TranslatorMap::Get(
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const SocketAddress& ext_ip) {
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TranslatorMap::iterator it = find(ext_ip);
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return (it != end()) ? it->second : nullptr;
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}
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NATSocketServer::Translator* NATSocketServer::TranslatorMap::Add(
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const SocketAddress& ext_ip,
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Translator* nat) {
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(*this)[ext_ip] = nat;
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return nat;
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}
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void NATSocketServer::TranslatorMap::Remove(const SocketAddress& ext_ip) {
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TranslatorMap::iterator it = find(ext_ip);
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if (it != end()) {
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delete it->second;
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erase(it);
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}
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}
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NATSocketServer::Translator* NATSocketServer::TranslatorMap::FindClient(
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const SocketAddress& int_ip) {
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Translator* nat = nullptr;
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for (TranslatorMap::iterator it = begin(); it != end() && !nat; ++it) {
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nat = it->second->FindClient(int_ip);
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}
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return nat;
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}
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} // namespace rtc
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