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/*
* Copyright 2017 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 "api/candidate.h"
#include <algorithm> // IWYU pragma: keep
#include <cstdint>
#include <string>
#include "absl/strings/string_view.h"
#include "p2p/base/p2p_constants.h"
#include "rtc_base/checks.h"
#include "rtc_base/crc32.h"
#include "rtc_base/crypto_random.h"
#include "rtc_base/ip_address.h"
#include "rtc_base/network_constants.h"
#include "rtc_base/socket_address.h"
#include "rtc_base/string_encode.h"
#include "rtc_base/strings/string_builder.h"
using webrtc::IceCandidateType;
namespace webrtc {
absl::string_view IceCandidateTypeToString(IceCandidateType type) {
switch (type) {
case IceCandidateType::kHost:
return "host";
case IceCandidateType::kSrflx:
return "srflx";
case IceCandidateType::kPrflx:
return "prflx";
case IceCandidateType::kRelay:
return "relay";
}
}
} // namespace webrtc
namespace cricket {
Candidate::Candidate()
: id_(rtc::CreateRandomString(8)),
component_(ICE_CANDIDATE_COMPONENT_DEFAULT),
priority_(0),
network_type_(rtc::ADAPTER_TYPE_UNKNOWN),
underlying_type_for_vpn_(rtc::ADAPTER_TYPE_UNKNOWN),
generation_(0),
network_id_(0),
network_cost_(0) {}
Candidate::Candidate(int component,
absl::string_view protocol,
const rtc::SocketAddress& address,
uint32_t priority,
absl::string_view username,
absl::string_view password,
webrtc::IceCandidateType type,
uint32_t generation,
absl::string_view foundation,
uint16_t network_id /*= 0*/,
uint16_t network_cost /*= 0*/)
: id_(rtc::CreateRandomString(8)),
component_(component),
protocol_(protocol),
address_(address),
priority_(priority),
username_(username),
password_(password),
type_(type),
network_type_(rtc::ADAPTER_TYPE_UNKNOWN),
underlying_type_for_vpn_(rtc::ADAPTER_TYPE_UNKNOWN),
generation_(generation),
foundation_(foundation),
network_id_(network_id),
network_cost_(network_cost) {}
Candidate::Candidate(const Candidate&) = default;
Candidate::~Candidate() = default;
void Candidate::generate_id() {
id_ = rtc::CreateRandomString(8);
}
bool Candidate::is_local() const {
return type_ == IceCandidateType::kHost;
}
bool Candidate::is_stun() const {
return type_ == IceCandidateType::kSrflx;
}
bool Candidate::is_prflx() const {
return type_ == IceCandidateType::kPrflx;
}
bool Candidate::is_relay() const {
return type_ == IceCandidateType::kRelay;
}
absl::string_view Candidate::type_name() const {
return webrtc::IceCandidateTypeToString(type_);
}
bool Candidate::IsEquivalent(const Candidate& c) const {
// We ignore the network name, since that is just debug information, and
// the priority and the network cost, since they should be the same if the
// rest are.
return (component_ == c.component_) && (protocol_ == c.protocol_) &&
(address_ == c.address_) && (username_ == c.username_) &&
(password_ == c.password_) && (type_ == c.type_) &&
(generation_ == c.generation_) && (foundation_ == c.foundation_) &&
(related_address_ == c.related_address_) &&
(network_id_ == c.network_id_);
}
bool Candidate::MatchesForRemoval(const Candidate& c) const {
return component_ == c.component_ && protocol_ == c.protocol_ &&
address_ == c.address_;
}
std::string Candidate::ToStringInternal(bool sensitive) const {
rtc::StringBuilder ost;
std::string address =
sensitive ? address_.ToSensitiveString() : address_.ToString();
std::string related_address = sensitive ? related_address_.ToSensitiveString()
: related_address_.ToString();
ost << "Cand[" << transport_name_ << ":" << foundation_ << ":" << component_
<< ":" << protocol_ << ":" << priority_ << ":" << address << ":"
<< type_name() << ":" << related_address << ":" << username_ << ":"
<< password_ << ":" << network_id_ << ":" << network_cost_ << ":"
<< generation_ << "]";
return ost.Release();
}
uint32_t Candidate::GetPriority(uint32_t type_preference,
int network_adapter_preference,
int relay_preference,
bool adjust_local_preference) const {
// RFC 5245 - 4.1.2.1.
// priority = (2^24)*(type preference) +
// (2^8)*(local preference) +
// (2^0)*(256 - component ID)
// `local_preference` length is 2 bytes, 0-65535 inclusive.
// In our implemenation we will partion local_preference into
// 0 1
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | NIC Pref | Addr Pref |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// NIC Type - Type of the network adapter e.g. 3G/Wifi/Wired.
// Addr Pref - Address preference value as per RFC 3484.
// local preference = (NIC Type << 8 | Addr_Pref) + relay preference.
// The relay preference is based on the number of TURN servers, the
// first TURN server gets the highest preference.
int addr_pref = IPAddressPrecedence(address_.ipaddr());
int local_preference =
((network_adapter_preference << 8) | addr_pref) + relay_preference;
// Ensure that the added relay preference will not result in a relay candidate
// whose STUN priority attribute has a higher priority than a server-reflexive
// candidate.
// The STUN priority attribute is calculated as
// (peer-reflexive type preference) << 24 | (priority & 0x00FFFFFF)
// as described in
// To satisfy that condition, add kMaxTurnServers to the local preference.
// This can not overflow the field width since the highest "NIC pref"
// assigned is kHighestNetworkPreference = 127
RTC_DCHECK_LT(local_preference + kMaxTurnServers, 0x10000);
if (adjust_local_preference && relay_protocol_.empty()) {
local_preference += kMaxTurnServers;
}
return (type_preference << 24) | (local_preference << 8) | (256 - component_);
}
bool Candidate::operator==(const Candidate& o) const {
return id_ == o.id_ && component_ == o.component_ &&
protocol_ == o.protocol_ && relay_protocol_ == o.relay_protocol_ &&
address_ == o.address_ && priority_ == o.priority_ &&
username_ == o.username_ && password_ == o.password_ &&
type_ == o.type_ && network_name_ == o.network_name_ &&
network_type_ == o.network_type_ && generation_ == o.generation_ &&
foundation_ == o.foundation_ &&
related_address_ == o.related_address_ && tcptype_ == o.tcptype_ &&
transport_name_ == o.transport_name_ && network_id_ == o.network_id_;
}
bool Candidate::operator!=(const Candidate& o) const {
return !(*this == o);
}
Candidate Candidate::ToSanitizedCopy(bool use_hostname_address,
bool filter_related_address) const {
Candidate copy(*this);
if (use_hostname_address) {
rtc::IPAddress ip;
if (address().hostname().empty()) {
// IP needs to be redacted, but no hostname available.
rtc::SocketAddress redacted_addr("redacted-ip.invalid", address().port());
copy.set_address(redacted_addr);
} else if (IPFromString(address().hostname(), &ip)) {
// The hostname is an IP literal, and needs to be redacted too.
rtc::SocketAddress redacted_addr("redacted-literal.invalid",
address().port());
copy.set_address(redacted_addr);
} else {
rtc::SocketAddress hostname_only_addr(address().hostname(),
address().port());
copy.set_address(hostname_only_addr);
}
}
if (filter_related_address) {
copy.set_related_address(
rtc::EmptySocketAddressWithFamily(copy.address().family()));
}
return copy;
}
void Candidate::ComputeFoundation(const rtc::SocketAddress& base_address,
uint64_t tie_breaker) {
// The foundation is an identifier, scoped within a session. Two candidates
// MUST have the same foundation ID when all of the following are true:
//
// o they are of the same type.
// o their bases have the same IP address (the ports can be different).
// o for reflexive and relayed candidates, the STUN or TURN servers used to
// obtain them have the same IP address.
// o they were obtained using the same transport protocol (TCP, UDP, etc.).
//
// Similarly, two candidates MUST have different foundations if their
// types are different, their bases have different IP addresses, the STUN or
// TURN servers used to obtain them have different IP addresses, or their
// transport protocols are different.
rtc::StringBuilder sb;
sb << type_name() << base_address.ipaddr().ToString() << protocol_
<< relay_protocol_;
// [...] it is possible for both agents to mistakenly believe they are
// controlled or controlling. To resolve this, each agent MUST select a random
// number, called the tie-breaker, uniformly distributed between 0 and (2**64)
// - 1 (that is, a 64-bit positive integer). This number is used in
// connectivity checks to detect and repair this case [...]
sb << rtc::ToString(tie_breaker);
foundation_ = rtc::ToString(rtc::ComputeCrc32(sb.Release()));
}
void Candidate::ComputePrflxFoundation() {
RTC_DCHECK(is_prflx());
RTC_DCHECK(!id_.empty());
foundation_ = rtc::ToString(rtc::ComputeCrc32(id_));
}
void Candidate::Assign(std::string& s, absl::string_view view) {
// Assigning via a temporary object, like s = std::string(view), results in
// binary size bloat. To avoid that, extract pointer and size from the
// string view, and use std::string::assign method.
s.assign(view.data(), view.size());
}
} // namespace cricket