324 lines
12 KiB
C++
324 lines
12 KiB
C++
/*
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* Copyright 2017 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 "pc/ice_server_parsing.h"
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#include <stddef.h>
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#include <algorithm>
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#include <cctype> // For std::isdigit.
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#include <memory>
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#include <string>
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#include "p2p/base/port_interface.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/ip_address.h"
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#include "rtc_base/logging.h"
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#include "rtc_base/socket_address.h"
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#include "rtc_base/string_encode.h"
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namespace webrtc {
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// Number of tokens must be preset when TURN uri has transport param.
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static const size_t kTurnTransportTokensNum = 2;
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// The default stun port.
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static const int kDefaultStunPort = 3478;
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static const int kDefaultStunTlsPort = 5349;
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static const char kTransport[] = "transport";
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// Allowed characters in hostname per RFC 3986 Appendix A "reg-name"
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static const char kRegNameCharacters[] =
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"abcdefghijklmnopqrstuvwxyz"
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"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
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"0123456789"
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"-._~" // unreserved
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"%" // pct-encoded
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"!$&'()*+,;="; // sub-delims
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// NOTE: Must be in the same order as the ServiceType enum.
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static const char* kValidIceServiceTypes[] = {"stun", "stuns", "turn", "turns"};
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// NOTE: A loop below assumes that the first value of this enum is 0 and all
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// other values are incremental.
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enum ServiceType {
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STUN = 0, // Indicates a STUN server.
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STUNS, // Indicates a STUN server used with a TLS session.
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TURN, // Indicates a TURN server
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TURNS, // Indicates a TURN server used with a TLS session.
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INVALID, // Unknown.
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};
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static_assert(INVALID == arraysize(kValidIceServiceTypes),
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"kValidIceServiceTypes must have as many strings as ServiceType "
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"has values.");
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// `in_str` should follow of RFC 7064/7065 syntax, but with an optional
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// "?transport=" already stripped. I.e.,
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// stunURI = scheme ":" host [ ":" port ]
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// scheme = "stun" / "stuns" / "turn" / "turns"
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// host = IP-literal / IPv4address / reg-name
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// port = *DIGIT
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static bool GetServiceTypeAndHostnameFromUri(const std::string& in_str,
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ServiceType* service_type,
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std::string* hostname) {
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const std::string::size_type colonpos = in_str.find(':');
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if (colonpos == std::string::npos) {
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RTC_LOG(LS_WARNING) << "Missing ':' in ICE URI: " << in_str;
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return false;
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}
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if ((colonpos + 1) == in_str.length()) {
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RTC_LOG(LS_WARNING) << "Empty hostname in ICE URI: " << in_str;
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return false;
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}
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*service_type = INVALID;
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for (size_t i = 0; i < arraysize(kValidIceServiceTypes); ++i) {
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if (in_str.compare(0, colonpos, kValidIceServiceTypes[i]) == 0) {
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*service_type = static_cast<ServiceType>(i);
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break;
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}
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}
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if (*service_type == INVALID) {
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return false;
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}
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*hostname = in_str.substr(colonpos + 1, std::string::npos);
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return true;
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}
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static bool ParsePort(const std::string& in_str, int* port) {
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// Make sure port only contains digits. FromString doesn't check this.
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for (const char& c : in_str) {
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if (!std::isdigit(c)) {
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return false;
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}
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}
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return rtc::FromString(in_str, port);
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}
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// This method parses IPv6 and IPv4 literal strings, along with hostnames in
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// standard hostname:port format.
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// Consider following formats as correct.
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// `hostname:port`, |[IPV6 address]:port|, |IPv4 address|:port,
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// `hostname`, |[IPv6 address]|, |IPv4 address|.
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static bool ParseHostnameAndPortFromString(const std::string& in_str,
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std::string* host,
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int* port) {
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RTC_DCHECK(host->empty());
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if (in_str.at(0) == '[') {
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// IP_literal syntax
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std::string::size_type closebracket = in_str.rfind(']');
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if (closebracket != std::string::npos) {
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std::string::size_type colonpos = in_str.find(':', closebracket);
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if (std::string::npos != colonpos) {
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if (!ParsePort(in_str.substr(closebracket + 2, std::string::npos),
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port)) {
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return false;
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}
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}
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*host = in_str.substr(1, closebracket - 1);
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} else {
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return false;
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}
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} else {
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// IPv4address or reg-name syntax
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std::string::size_type colonpos = in_str.find(':');
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if (std::string::npos != colonpos) {
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if (!ParsePort(in_str.substr(colonpos + 1, std::string::npos), port)) {
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return false;
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}
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*host = in_str.substr(0, colonpos);
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} else {
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*host = in_str;
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}
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// RFC 3986 section 3.2.2 and Appendix A - "reg-name" syntax
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if (host->find_first_not_of(kRegNameCharacters) != std::string::npos) {
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return false;
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}
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}
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return !host->empty();
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}
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// Adds a STUN or TURN server to the appropriate list,
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// by parsing `url` and using the username/password in `server`.
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static RTCErrorType ParseIceServerUrl(
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const PeerConnectionInterface::IceServer& server,
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const std::string& url,
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cricket::ServerAddresses* stun_servers,
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std::vector<cricket::RelayServerConfig>* turn_servers) {
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// RFC 7064
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// stunURI = scheme ":" host [ ":" port ]
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// scheme = "stun" / "stuns"
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// RFC 7065
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// turnURI = scheme ":" host [ ":" port ]
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// [ "?transport=" transport ]
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// scheme = "turn" / "turns"
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// transport = "udp" / "tcp" / transport-ext
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// transport-ext = 1*unreserved
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// RFC 3986
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// host = IP-literal / IPv4address / reg-name
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// port = *DIGIT
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RTC_DCHECK(stun_servers != nullptr);
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RTC_DCHECK(turn_servers != nullptr);
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std::vector<std::string> tokens;
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cricket::ProtocolType turn_transport_type = cricket::PROTO_UDP;
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RTC_DCHECK(!url.empty());
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rtc::split(url, '?', &tokens);
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std::string uri_without_transport = tokens[0];
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// Let's look into transport= param, if it exists.
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if (tokens.size() == kTurnTransportTokensNum) { // ?transport= is present.
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std::string uri_transport_param = tokens[1];
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rtc::split(uri_transport_param, '=', &tokens);
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if (tokens[0] != kTransport) {
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RTC_LOG(LS_WARNING) << "Invalid transport parameter key.";
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return RTCErrorType::SYNTAX_ERROR;
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}
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if (tokens.size() < 2) {
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RTC_LOG(LS_WARNING) << "Transport parameter missing value.";
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return RTCErrorType::SYNTAX_ERROR;
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}
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if (!cricket::StringToProto(tokens[1].c_str(), &turn_transport_type) ||
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(turn_transport_type != cricket::PROTO_UDP &&
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turn_transport_type != cricket::PROTO_TCP)) {
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RTC_LOG(LS_WARNING) << "Transport parameter should always be udp or tcp.";
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return RTCErrorType::SYNTAX_ERROR;
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}
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}
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std::string hoststring;
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ServiceType service_type;
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if (!GetServiceTypeAndHostnameFromUri(uri_without_transport, &service_type,
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&hoststring)) {
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RTC_LOG(LS_WARNING) << "Invalid transport parameter in ICE URI: " << url;
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return RTCErrorType::SYNTAX_ERROR;
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}
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// GetServiceTypeAndHostnameFromUri should never give an empty hoststring
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RTC_DCHECK(!hoststring.empty());
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int port = kDefaultStunPort;
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if (service_type == TURNS) {
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port = kDefaultStunTlsPort;
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turn_transport_type = cricket::PROTO_TLS;
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}
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if (hoststring.find('@') != std::string::npos) {
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RTC_LOG(LS_WARNING) << "Invalid url: " << uri_without_transport;
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RTC_LOG(LS_WARNING)
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<< "Note that user-info@ in turn:-urls is long-deprecated.";
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return RTCErrorType::SYNTAX_ERROR;
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}
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std::string address;
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if (!ParseHostnameAndPortFromString(hoststring, &address, &port)) {
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RTC_LOG(LS_WARNING) << "Invalid hostname format: " << uri_without_transport;
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return RTCErrorType::SYNTAX_ERROR;
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}
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if (port <= 0 || port > 0xffff) {
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RTC_LOG(LS_WARNING) << "Invalid port: " << port;
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return RTCErrorType::SYNTAX_ERROR;
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}
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switch (service_type) {
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case STUN:
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case STUNS:
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stun_servers->insert(rtc::SocketAddress(address, port));
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break;
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case TURN:
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case TURNS: {
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if (server.username.empty() || server.password.empty()) {
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// The WebRTC spec requires throwing an InvalidAccessError when username
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// or credential are ommitted; this is the native equivalent.
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RTC_LOG(LS_WARNING) << "TURN server with empty username or password";
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return RTCErrorType::INVALID_PARAMETER;
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}
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// If the hostname field is not empty, then the server address must be
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// the resolved IP for that host, the hostname is needed later for TLS
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// handshake (SNI and Certificate verification).
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const std::string& hostname =
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server.hostname.empty() ? address : server.hostname;
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rtc::SocketAddress socket_address(hostname, port);
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if (!server.hostname.empty()) {
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rtc::IPAddress ip;
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if (!IPFromString(address, &ip)) {
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// When hostname is set, the server address must be a
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// resolved ip address.
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RTC_LOG(LS_WARNING)
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<< "IceServer has hostname field set, but URI does not "
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"contain an IP address.";
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return RTCErrorType::INVALID_PARAMETER;
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}
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socket_address.SetResolvedIP(ip);
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}
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cricket::RelayServerConfig config =
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cricket::RelayServerConfig(socket_address, server.username,
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server.password, turn_transport_type);
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if (server.tls_cert_policy ==
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PeerConnectionInterface::kTlsCertPolicyInsecureNoCheck) {
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config.tls_cert_policy =
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cricket::TlsCertPolicy::TLS_CERT_POLICY_INSECURE_NO_CHECK;
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}
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config.tls_alpn_protocols = server.tls_alpn_protocols;
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config.tls_elliptic_curves = server.tls_elliptic_curves;
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turn_servers->push_back(config);
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break;
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}
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default:
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// We shouldn't get to this point with an invalid service_type, we should
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// have returned an error already.
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RTC_DCHECK_NOTREACHED() << "Unexpected service type";
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return RTCErrorType::INTERNAL_ERROR;
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}
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return RTCErrorType::NONE;
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}
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RTCErrorType ParseIceServers(
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const PeerConnectionInterface::IceServers& servers,
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cricket::ServerAddresses* stun_servers,
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std::vector<cricket::RelayServerConfig>* turn_servers) {
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for (const PeerConnectionInterface::IceServer& server : servers) {
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if (!server.urls.empty()) {
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for (const std::string& url : server.urls) {
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if (url.empty()) {
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RTC_LOG(LS_WARNING) << "Empty uri.";
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return RTCErrorType::SYNTAX_ERROR;
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}
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RTCErrorType err =
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ParseIceServerUrl(server, url, stun_servers, turn_servers);
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if (err != RTCErrorType::NONE) {
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return err;
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}
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}
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} else if (!server.uri.empty()) {
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// Fallback to old .uri if new .urls isn't present.
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RTCErrorType err =
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ParseIceServerUrl(server, server.uri, stun_servers, turn_servers);
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if (err != RTCErrorType::NONE) {
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return err;
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}
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} else {
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RTC_LOG(LS_WARNING) << "Empty uri.";
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return RTCErrorType::SYNTAX_ERROR;
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}
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}
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// Candidates must have unique priorities, so that connectivity checks
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// are performed in a well-defined order.
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int priority = static_cast<int>(turn_servers->size() - 1);
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for (cricket::RelayServerConfig& turn_server : *turn_servers) {
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// First in the list gets highest priority.
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turn_server.priority = priority--;
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}
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return RTCErrorType::NONE;
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}
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} // namespace webrtc
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