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/*
* Copyright 2013 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 "pc/sctp_utils.h"
#include <stddef.h>
#include <cstdint>
#include "absl/types/optional.h"
#include "api/priority.h"
#include "rtc_base/byte_buffer.h"
#include "rtc_base/copy_on_write_buffer.h"
#include "rtc_base/logging.h"
namespace webrtc {
// Format defined at
// http://tools.ietf.org/html/draft-ietf-rtcweb-data-protocol-01#section
static const uint8_t DATA_CHANNEL_OPEN_MESSAGE_TYPE = 0x03;
static const uint8_t DATA_CHANNEL_OPEN_ACK_MESSAGE_TYPE = 0x02;
enum DataChannelOpenMessageChannelType {
DCOMCT_ORDERED_RELIABLE = 0x00,
DCOMCT_ORDERED_PARTIAL_RTXS = 0x01,
DCOMCT_ORDERED_PARTIAL_TIME = 0x02,
DCOMCT_UNORDERED_RELIABLE = 0x80,
DCOMCT_UNORDERED_PARTIAL_RTXS = 0x81,
DCOMCT_UNORDERED_PARTIAL_TIME = 0x82,
};
// Values of priority in the DC open protocol message.
// These are compared against an integer, so are enum, not enum class.
enum DataChannelPriority {
DCO_PRIORITY_VERY_LOW = 128,
DCO_PRIORITY_LOW = 256,
DCO_PRIORITY_MEDIUM = 512,
DCO_PRIORITY_HIGH = 1024,
};
bool IsOpenMessage(const rtc::CopyOnWriteBuffer& payload) {
// Format defined at
// https://www.rfc-editor.org/rfc/rfc8832#section-5.1
if (payload.size() < 1) {
RTC_DLOG(LS_WARNING) << "Could not read OPEN message type.";
return false;
}
uint8_t message_type = payload[0];
return message_type == DATA_CHANNEL_OPEN_MESSAGE_TYPE;
}
bool ParseDataChannelOpenMessage(const rtc::CopyOnWriteBuffer& payload,
std::string* label,
DataChannelInit* config) {
// Format defined at
// http://tools.ietf.org/html/draft-jesup-rtcweb-data-protocol-04
rtc::ByteBufferReader buffer(payload);
uint8_t message_type;
if (!buffer.ReadUInt8(&message_type)) {
RTC_LOG(LS_WARNING) << "Could not read OPEN message type.";
return false;
}
if (message_type != DATA_CHANNEL_OPEN_MESSAGE_TYPE) {
RTC_LOG(LS_WARNING) << "Data Channel OPEN message of unexpected type: "
<< message_type;
return false;
}
uint8_t channel_type;
if (!buffer.ReadUInt8(&channel_type)) {
RTC_LOG(LS_WARNING) << "Could not read OPEN message channel type.";
return false;
}
uint16_t priority;
if (!buffer.ReadUInt16(&priority)) {
RTC_LOG(LS_WARNING)
<< "Could not read OPEN message reliabilility prioirty.";
return false;
}
// Parse priority as defined in
// https://w3c.github.io/webrtc-priority/#rtcdatachannel-processing-steps
if (priority <= DCO_PRIORITY_VERY_LOW) {
config->priority = Priority::kVeryLow;
} else if (priority <= DCO_PRIORITY_LOW) {
config->priority = Priority::kLow;
} else if (priority <= DCO_PRIORITY_MEDIUM) {
config->priority = Priority::kMedium;
} else {
config->priority = Priority::kHigh;
}
uint32_t reliability_param;
if (!buffer.ReadUInt32(&reliability_param)) {
RTC_LOG(LS_WARNING) << "Could not read OPEN message reliabilility param.";
return false;
}
uint16_t label_length;
if (!buffer.ReadUInt16(&label_length)) {
RTC_LOG(LS_WARNING) << "Could not read OPEN message label length.";
return false;
}
uint16_t protocol_length;
if (!buffer.ReadUInt16(&protocol_length)) {
RTC_LOG(LS_WARNING) << "Could not read OPEN message protocol length.";
return false;
}
if (!buffer.ReadString(label, (size_t)label_length)) {
RTC_LOG(LS_WARNING) << "Could not read OPEN message label";
return false;
}
if (!buffer.ReadString(&config->protocol, protocol_length)) {
RTC_LOG(LS_WARNING) << "Could not read OPEN message protocol.";
return false;
}
config->ordered = true;
switch (channel_type) {
case DCOMCT_UNORDERED_RELIABLE:
case DCOMCT_UNORDERED_PARTIAL_RTXS:
case DCOMCT_UNORDERED_PARTIAL_TIME:
config->ordered = false;
}
config->maxRetransmits = absl::nullopt;
config->maxRetransmitTime = absl::nullopt;
switch (channel_type) {
case DCOMCT_ORDERED_PARTIAL_RTXS:
case DCOMCT_UNORDERED_PARTIAL_RTXS:
config->maxRetransmits = reliability_param;
break;
case DCOMCT_ORDERED_PARTIAL_TIME:
case DCOMCT_UNORDERED_PARTIAL_TIME:
config->maxRetransmitTime = reliability_param;
break;
}
return true;
}
bool ParseDataChannelOpenAckMessage(const rtc::CopyOnWriteBuffer& payload) {
if (payload.size() < 1) {
RTC_LOG(LS_WARNING) << "Could not read OPEN_ACK message type.";
return false;
}
uint8_t message_type = payload[0];
if (message_type != DATA_CHANNEL_OPEN_ACK_MESSAGE_TYPE) {
RTC_LOG(LS_WARNING) << "Data Channel OPEN_ACK message of unexpected type: "
<< message_type;
return false;
}
return true;
}
bool WriteDataChannelOpenMessage(const std::string& label,
const DataChannelInit& config,
rtc::CopyOnWriteBuffer* payload) {
return WriteDataChannelOpenMessage(label, config.protocol, config.priority,
config.ordered, config.maxRetransmits,
config.maxRetransmitTime, payload);
}
bool WriteDataChannelOpenMessage(const std::string& label,
const std::string& protocol,
absl::optional<Priority> opt_priority,
bool ordered,
absl::optional<int> max_retransmits,
absl::optional<int> max_retransmit_time,
rtc::CopyOnWriteBuffer* payload) {
// Format defined at
// http://tools.ietf.org/html/draft-ietf-rtcweb-data-protocol-09#section-5.1
uint8_t channel_type = 0;
uint32_t reliability_param = 0;
uint16_t priority = 0;
// Set priority according to
// https://tools.ietf.org/html/draft-ietf-rtcweb-data-channel-12#section-6.4
if (opt_priority) {
switch (*opt_priority) {
case Priority::kVeryLow:
priority = DCO_PRIORITY_VERY_LOW;
break;
case Priority::kLow:
priority = DCO_PRIORITY_LOW;
break;
case Priority::kMedium:
priority = DCO_PRIORITY_MEDIUM;
break;
case Priority::kHigh:
priority = DCO_PRIORITY_HIGH;
break;
}
}
if (ordered) {
if (max_retransmits) {
channel_type = DCOMCT_ORDERED_PARTIAL_RTXS;
reliability_param = *max_retransmits;
} else if (max_retransmit_time) {
channel_type = DCOMCT_ORDERED_PARTIAL_TIME;
reliability_param = *max_retransmit_time;
} else {
channel_type = DCOMCT_ORDERED_RELIABLE;
}
} else {
if (max_retransmits) {
channel_type = DCOMCT_UNORDERED_PARTIAL_RTXS;
reliability_param = *max_retransmits;
} else if (max_retransmit_time) {
channel_type = DCOMCT_UNORDERED_PARTIAL_TIME;
reliability_param = *max_retransmit_time;
} else {
channel_type = DCOMCT_UNORDERED_RELIABLE;
}
}
rtc::ByteBufferWriter buffer(NULL, 20 + label.length() + protocol.length());
// TODO(tommi): Add error handling and check resulting length.
buffer.WriteUInt8(DATA_CHANNEL_OPEN_MESSAGE_TYPE);
buffer.WriteUInt8(channel_type);
buffer.WriteUInt16(priority);
buffer.WriteUInt32(reliability_param);
buffer.WriteUInt16(static_cast<uint16_t>(label.length()));
buffer.WriteUInt16(static_cast<uint16_t>(protocol.length()));
buffer.WriteString(label);
buffer.WriteString(protocol);
payload->SetData(buffer.Data(), buffer.Length());
return true;
}
void WriteDataChannelOpenAckMessage(rtc::CopyOnWriteBuffer* payload) {
uint8_t data = DATA_CHANNEL_OPEN_ACK_MESSAGE_TYPE;
payload->SetData(&data, sizeof(data));
}
} // namespace webrtc
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