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-rw-r--r--third_party/libwebrtc/rtc_base/nat_server.cc255
1 files changed, 255 insertions, 0 deletions
diff --git a/third_party/libwebrtc/rtc_base/nat_server.cc b/third_party/libwebrtc/rtc_base/nat_server.cc
new file mode 100644
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+++ b/third_party/libwebrtc/rtc_base/nat_server.cc
@@ -0,0 +1,255 @@
+/*
+ * Copyright 2004 The WebRTC Project Authors. All rights reserved.
+ *
+ * Use of this source code is governed by a BSD-style license
+ * that can be found in the LICENSE file in the root of the source
+ * tree. An additional intellectual property rights grant can be found
+ * in the file PATENTS. All contributing project authors may
+ * be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "rtc_base/nat_server.h"
+
+#include <memory>
+
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/nat_socket_factory.h"
+#include "rtc_base/socket_adapters.h"
+
+namespace rtc {
+
+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;
+}
+
+// Proxy socket that will capture the external destination address intended for
+// a TCP connection to the NAT server.
+class NATProxyServerSocket : public AsyncProxyServerSocket {
+ public:
+ NATProxyServerSocket(Socket* socket)
+ : AsyncProxyServerSocket(socket, kNATEncodedIPv6AddressSize) {
+ BufferInput(true);
+ }
+
+ void SendConnectResult(int err, const SocketAddress& addr) override {
+ char code = err ? 1 : 0;
+ BufferedReadAdapter::DirectSend(&code, sizeof(char));
+ }
+
+ protected:
+ void ProcessInput(char* data, size_t* len) override {
+ if (*len < 2) {
+ return;
+ }
+
+ int family = data[1];
+ RTC_DCHECK(family == AF_INET || family == AF_INET6);
+ if ((family == AF_INET && *len < kNATEncodedIPv4AddressSize) ||
+ (family == AF_INET6 && *len < kNATEncodedIPv6AddressSize)) {
+ return;
+ }
+
+ SocketAddress dest_addr;
+ size_t address_length = UnpackAddressFromNAT(data, *len, &dest_addr);
+
+ *len -= address_length;
+ if (*len > 0) {
+ memmove(data, data + address_length, *len);
+ }
+
+ bool remainder = (*len > 0);
+ BufferInput(false);
+ SignalConnectRequest(this, dest_addr);
+ if (remainder) {
+ SignalReadEvent(this);
+ }
+ }
+};
+
+class NATProxyServer : public ProxyServer {
+ public:
+ NATProxyServer(SocketFactory* int_factory,
+ const SocketAddress& int_addr,
+ SocketFactory* ext_factory,
+ const SocketAddress& ext_ip)
+ : ProxyServer(int_factory, int_addr, ext_factory, ext_ip) {}
+
+ protected:
+ AsyncProxyServerSocket* WrapSocket(Socket* socket) override {
+ return new NATProxyServerSocket(socket);
+ }
+};
+
+NATServer::NATServer(NATType type,
+ SocketFactory* internal,
+ const SocketAddress& internal_udp_addr,
+ const SocketAddress& internal_tcp_addr,
+ SocketFactory* external,
+ const SocketAddress& external_ip)
+ : external_(external), external_ip_(external_ip.ipaddr(), 0) {
+ nat_ = NAT::Create(type);
+
+ udp_server_socket_ = AsyncUDPSocket::Create(internal, internal_udp_addr);
+ udp_server_socket_->SignalReadPacket.connect(this,
+ &NATServer::OnInternalUDPPacket);
+ tcp_proxy_server_ =
+ new NATProxyServer(internal, internal_tcp_addr, external, external_ip);
+
+ 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 udp_server_socket_;
+ delete tcp_proxy_server_;
+ delete int_map_;
+ delete ext_map_;
+}
+
+void NATServer::OnInternalUDPPacket(AsyncPacketSocket* socket,
+ const char* buf,
+ size_t size,
+ const SocketAddress& addr,
+ const int64_t& /* packet_time_us */) {
+ // 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);
+ }
+ RTC_DCHECK(iter != int_map_->end());
+
+ // Allow the destination to send packets back to the source.
+ iter->second->AllowlistInsert(dest_addr);
+
+ // Send the packet to its intended destination.
+ rtc::PacketOptions options;
+ iter->second->socket->SendTo(buf + length, size - length, dest_addr, options);
+}
+
+void NATServer::OnExternalUDPPacket(AsyncPacketSocket* socket,
+ const char* buf,
+ size_t size,
+ const SocketAddress& remote_addr,
+ const int64_t& /* packet_time_us */) {
+ SocketAddress local_addr = socket->GetLocalAddress();
+
+ // Find the translation for this addresses.
+ ExternalMap::iterator iter = ext_map_->find(local_addr);
+ RTC_DCHECK(iter != ext_map_->end());
+
+ // Allow the NAT to reject this packet.
+ if (ShouldFilterOut(iter->second, remote_addr)) {
+ RTC_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.
+ std::unique_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.
+ rtc::PacketOptions options;
+ memcpy(real_buf.get() + addrlength, buf, size);
+ udp_server_socket_->SendTo(real_buf.get(), size + addrlength,
+ iter->second->route.source(), options);
+}
+
+void NATServer::Translate(const SocketAddressPair& route) {
+ AsyncUDPSocket* socket = AsyncUDPSocket::Create(external_, external_ip_);
+
+ if (!socket) {
+ RTC_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::OnExternalUDPPacket);
+}
+
+bool NATServer::ShouldFilterOut(TransEntry* entry,
+ const SocketAddress& ext_addr) {
+ return entry->AllowlistContains(ext_addr);
+}
+
+NATServer::TransEntry::TransEntry(const SocketAddressPair& r,
+ AsyncUDPSocket* s,
+ NAT* nat)
+ : route(r), socket(s) {
+ allowlist = new AddressSet(AddrCmp(nat));
+}
+
+NATServer::TransEntry::~TransEntry() {
+ delete allowlist;
+ delete socket;
+}
+
+void NATServer::TransEntry::AllowlistInsert(const SocketAddress& addr) {
+ webrtc::MutexLock lock(&mutex_);
+ allowlist->insert(addr);
+}
+
+bool NATServer::TransEntry::AllowlistContains(const SocketAddress& ext_addr) {
+ webrtc::MutexLock lock(&mutex_);
+ return allowlist->find(ext_addr) == allowlist->end();
+}
+
+} // namespace rtc