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Diffstat (limited to 'third_party/libwebrtc/webrtc/media/base/rtputils.cc')
-rw-r--r--third_party/libwebrtc/webrtc/media/base/rtputils.cc473
1 files changed, 473 insertions, 0 deletions
diff --git a/third_party/libwebrtc/webrtc/media/base/rtputils.cc b/third_party/libwebrtc/webrtc/media/base/rtputils.cc
new file mode 100644
index 0000000000..d0ba1cf72b
--- /dev/null
+++ b/third_party/libwebrtc/webrtc/media/base/rtputils.cc
@@ -0,0 +1,473 @@
+/*
+ * Copyright (c) 2011 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 "media/base/rtputils.h"
+
+// PacketTimeUpdateParams is defined in asyncpacketsocket.h.
+// TODO(sergeyu): Find more appropriate place for PacketTimeUpdateParams.
+#include "media/base/turnutils.h"
+#include "rtc_base/asyncpacketsocket.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/messagedigest.h"
+
+namespace cricket {
+
+static const uint8_t kRtpVersion = 2;
+static const size_t kRtpFlagsOffset = 0;
+static const size_t kRtpPayloadTypeOffset = 1;
+static const size_t kRtpSeqNumOffset = 2;
+static const size_t kRtpTimestampOffset = 4;
+static const size_t kRtpSsrcOffset = 8;
+static const size_t kRtcpPayloadTypeOffset = 1;
+static const size_t kRtpExtensionHeaderLen = 4;
+static const size_t kAbsSendTimeExtensionLen = 3;
+static const size_t kOneByteExtensionHeaderLen = 1;
+
+namespace {
+
+// Fake auth tag written by the sender when external authentication is enabled.
+// HMAC in packet will be compared against this value before updating packet
+// with actual HMAC value.
+static const uint8_t kFakeAuthTag[10] = {
+ 0xba, 0xdd, 0xba, 0xdd, 0xba, 0xdd, 0xba, 0xdd, 0xba, 0xdd
+};
+
+void UpdateAbsSendTimeExtensionValue(uint8_t* extension_data,
+ size_t length,
+ uint64_t time_us) {
+ // Absolute send time in RTP streams.
+ //
+ // The absolute send time is signaled to the receiver in-band using the
+ // general mechanism for RTP header extensions [RFC5285]. The payload
+ // of this extension (the transmitted value) is a 24-bit unsigned integer
+ // containing the sender's current time in seconds as a fixed point number
+ // with 18 bits fractional part.
+ //
+ // The form of the absolute send time extension block:
+ //
+ // 0 1 2 3
+ // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ // | ID | len=2 | absolute send time |
+ // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ if (length != kAbsSendTimeExtensionLen) {
+ RTC_NOTREACHED();
+ return;
+ }
+
+ // Convert microseconds to a 6.18 fixed point value in seconds.
+ uint32_t send_time = ((time_us << 18) / 1000000) & 0x00FFFFFF;
+ extension_data[0] = static_cast<uint8_t>(send_time >> 16);
+ extension_data[1] = static_cast<uint8_t>(send_time >> 8);
+ extension_data[2] = static_cast<uint8_t>(send_time);
+}
+
+// Assumes |length| is actual packet length + tag length. Updates HMAC at end of
+// the RTP packet.
+void UpdateRtpAuthTag(uint8_t* rtp,
+ size_t length,
+ const rtc::PacketTimeUpdateParams& packet_time_params) {
+ // If there is no key, return.
+ if (packet_time_params.srtp_auth_key.empty()) {
+ return;
+ }
+
+ size_t tag_length = packet_time_params.srtp_auth_tag_len;
+
+ // ROC (rollover counter) is at the beginning of the auth tag.
+ const size_t kRocLength = 4;
+ if (tag_length < kRocLength || tag_length > length) {
+ RTC_NOTREACHED();
+ return;
+ }
+
+ uint8_t* auth_tag = rtp + (length - tag_length);
+
+ // We should have a fake HMAC value @ auth_tag.
+ RTC_DCHECK_EQ(0, memcmp(auth_tag, kFakeAuthTag, tag_length));
+
+ // Copy ROC after end of rtp packet.
+ memcpy(auth_tag, &packet_time_params.srtp_packet_index, kRocLength);
+ // Authentication of a RTP packet will have RTP packet + ROC size.
+ size_t auth_required_length = length - tag_length + kRocLength;
+
+ uint8_t output[64];
+ size_t result = rtc::ComputeHmac(
+ rtc::DIGEST_SHA_1, &packet_time_params.srtp_auth_key[0],
+ packet_time_params.srtp_auth_key.size(), rtp,
+ auth_required_length, output, sizeof(output));
+
+ if (result < tag_length) {
+ RTC_NOTREACHED();
+ return;
+ }
+
+ // Copy HMAC from output to packet. This is required as auth tag length
+ // may not be equal to the actual HMAC length.
+ memcpy(auth_tag, output, tag_length);
+}
+
+} // namespace
+
+bool GetUint8(const void* data, size_t offset, int* value) {
+ if (!data || !value) {
+ return false;
+ }
+ *value = *(static_cast<const uint8_t*>(data) + offset);
+ return true;
+}
+
+bool GetUint16(const void* data, size_t offset, int* value) {
+ if (!data || !value) {
+ return false;
+ }
+ *value = static_cast<int>(
+ rtc::GetBE16(static_cast<const uint8_t*>(data) + offset));
+ return true;
+}
+
+bool GetUint32(const void* data, size_t offset, uint32_t* value) {
+ if (!data || !value) {
+ return false;
+ }
+ *value = rtc::GetBE32(static_cast<const uint8_t*>(data) + offset);
+ return true;
+}
+
+bool SetUint8(void* data, size_t offset, uint8_t value) {
+ if (!data) {
+ return false;
+ }
+ rtc::Set8(data, offset, value);
+ return true;
+}
+
+bool SetUint16(void* data, size_t offset, uint16_t value) {
+ if (!data) {
+ return false;
+ }
+ rtc::SetBE16(static_cast<uint8_t*>(data) + offset, value);
+ return true;
+}
+
+bool SetUint32(void* data, size_t offset, uint32_t value) {
+ if (!data) {
+ return false;
+ }
+ rtc::SetBE32(static_cast<uint8_t*>(data) + offset, value);
+ return true;
+}
+
+bool GetRtpFlags(const void* data, size_t len, int* value) {
+ if (len < kMinRtpPacketLen) {
+ return false;
+ }
+ return GetUint8(data, kRtpFlagsOffset, value);
+}
+
+bool GetRtpPayloadType(const void* data, size_t len, int* value) {
+ if (len < kMinRtpPacketLen) {
+ return false;
+ }
+ if (!GetUint8(data, kRtpPayloadTypeOffset, value)) {
+ return false;
+ }
+ *value &= 0x7F;
+ return true;
+}
+
+bool GetRtpSeqNum(const void* data, size_t len, int* value) {
+ if (len < kMinRtpPacketLen) {
+ return false;
+ }
+ return GetUint16(data, kRtpSeqNumOffset, value);
+}
+
+bool GetRtpTimestamp(const void* data, size_t len, uint32_t* value) {
+ if (len < kMinRtpPacketLen) {
+ return false;
+ }
+ return GetUint32(data, kRtpTimestampOffset, value);
+}
+
+bool GetRtpSsrc(const void* data, size_t len, uint32_t* value) {
+ if (len < kMinRtpPacketLen) {
+ return false;
+ }
+ return GetUint32(data, kRtpSsrcOffset, value);
+}
+
+bool GetRtpHeaderLen(const void* data, size_t len, size_t* value) {
+ if (!data || len < kMinRtpPacketLen || !value) return false;
+ const uint8_t* header = static_cast<const uint8_t*>(data);
+ // Get base header size + length of CSRCs (not counting extension yet).
+ size_t header_size = kMinRtpPacketLen + (header[0] & 0xF) * sizeof(uint32_t);
+ if (len < header_size) return false;
+ // If there's an extension, read and add in the extension size.
+ if (header[0] & 0x10) {
+ if (len < header_size + sizeof(uint32_t))
+ return false;
+ header_size +=
+ ((rtc::GetBE16(header + header_size + 2) + 1) * sizeof(uint32_t));
+ if (len < header_size) return false;
+ }
+ *value = header_size;
+ return true;
+}
+
+bool GetRtpHeader(const void* data, size_t len, RtpHeader* header) {
+ return (GetRtpPayloadType(data, len, &(header->payload_type)) &&
+ GetRtpSeqNum(data, len, &(header->seq_num)) &&
+ GetRtpTimestamp(data, len, &(header->timestamp)) &&
+ GetRtpSsrc(data, len, &(header->ssrc)));
+}
+
+bool GetRtcpType(const void* data, size_t len, int* value) {
+ if (len < kMinRtcpPacketLen) {
+ return false;
+ }
+ return GetUint8(data, kRtcpPayloadTypeOffset, value);
+}
+
+// This method returns SSRC first of RTCP packet, except if packet is SDES.
+// TODO(mallinath) - Fully implement RFC 5506. This standard doesn't restrict
+// to send non-compound packets only to feedback messages.
+bool GetRtcpSsrc(const void* data, size_t len, uint32_t* value) {
+ // Packet should be at least of 8 bytes, to get SSRC from a RTCP packet.
+ if (!data || len < kMinRtcpPacketLen + 4 || !value) return false;
+ int pl_type;
+ if (!GetRtcpType(data, len, &pl_type)) return false;
+ // SDES packet parsing is not supported.
+ if (pl_type == kRtcpTypeSDES) return false;
+ *value = rtc::GetBE32(static_cast<const uint8_t*>(data) + 4);
+ return true;
+}
+
+bool SetRtpSsrc(void* data, size_t len, uint32_t value) {
+ return SetUint32(data, kRtpSsrcOffset, value);
+}
+
+// Assumes version 2, no padding, no extensions, no csrcs.
+bool SetRtpHeader(void* data, size_t len, const RtpHeader& header) {
+ if (!IsValidRtpPayloadType(header.payload_type) ||
+ header.seq_num < 0 || header.seq_num > UINT16_MAX) {
+ return false;
+ }
+ return (SetUint8(data, kRtpFlagsOffset, kRtpVersion << 6) &&
+ SetUint8(data, kRtpPayloadTypeOffset, header.payload_type & 0x7F) &&
+ SetUint16(data, kRtpSeqNumOffset,
+ static_cast<uint16_t>(header.seq_num)) &&
+ SetUint32(data, kRtpTimestampOffset, header.timestamp) &&
+ SetRtpSsrc(data, len, header.ssrc));
+}
+
+bool IsRtpPacket(const void* data, size_t len) {
+ if (len < kMinRtpPacketLen)
+ return false;
+
+ return (static_cast<const uint8_t*>(data)[0] >> 6) == kRtpVersion;
+}
+
+bool IsValidRtpPayloadType(int payload_type) {
+ return payload_type >= 0 && payload_type <= 127;
+}
+
+bool IsValidRtpRtcpPacketSize(bool rtcp, size_t size) {
+ return (rtcp ? size >= kMinRtcpPacketLen : size >= kMinRtpPacketLen) &&
+ size <= kMaxRtpPacketLen;
+}
+
+const char* RtpRtcpStringLiteral(bool rtcp) {
+ return rtcp ? "RTCP" : "RTP";
+}
+
+bool ValidateRtpHeader(const uint8_t* rtp,
+ size_t length,
+ size_t* header_length) {
+ if (header_length) {
+ *header_length = 0;
+ }
+
+ if (length < kMinRtpPacketLen) {
+ return false;
+ }
+
+ size_t cc_count = rtp[0] & 0x0F;
+ size_t header_length_without_extension = kMinRtpPacketLen + 4 * cc_count;
+ if (header_length_without_extension > length) {
+ return false;
+ }
+
+ // If extension bit is not set, we are done with header processing, as input
+ // length is verified above.
+ if (!(rtp[0] & 0x10)) {
+ if (header_length)
+ *header_length = header_length_without_extension;
+
+ return true;
+ }
+
+ rtp += header_length_without_extension;
+
+ if (header_length_without_extension + kRtpExtensionHeaderLen > length) {
+ return false;
+ }
+
+ // Getting extension profile length.
+ // Length is in 32 bit words.
+ uint16_t extension_length_in_32bits = rtc::GetBE16(rtp + 2);
+ size_t extension_length = extension_length_in_32bits * 4;
+
+ size_t rtp_header_length = extension_length +
+ header_length_without_extension +
+ kRtpExtensionHeaderLen;
+
+ // Verify input length against total header size.
+ if (rtp_header_length > length) {
+ return false;
+ }
+
+ if (header_length) {
+ *header_length = rtp_header_length;
+ }
+ return true;
+}
+
+// ValidateRtpHeader() must be called before this method to make sure, we have
+// a sane rtp packet.
+bool UpdateRtpAbsSendTimeExtension(uint8_t* rtp,
+ size_t length,
+ int extension_id,
+ uint64_t time_us) {
+ // 0 1 2 3
+ // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ // |V=2|P|X| CC |M| PT | sequence number |
+ // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ // | timestamp |
+ // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ // | synchronization source (SSRC) identifier |
+ // +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
+ // | contributing source (CSRC) identifiers |
+ // | .... |
+ // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+ // Return if extension bit is not set.
+ if (!(rtp[0] & 0x10)) {
+ return true;
+ }
+
+ size_t cc_count = rtp[0] & 0x0F;
+ size_t header_length_without_extension = kMinRtpPacketLen + 4 * cc_count;
+
+ rtp += header_length_without_extension;
+
+ // Getting extension profile ID and length.
+ uint16_t profile_id = rtc::GetBE16(rtp);
+ // Length is in 32 bit words.
+ uint16_t extension_length_in_32bits = rtc::GetBE16(rtp + 2);
+ size_t extension_length = extension_length_in_32bits * 4;
+
+ rtp += kRtpExtensionHeaderLen; // Moving past extension header.
+
+ bool found = false;
+ // WebRTC is using one byte header extension.
+ // TODO(mallinath) - Handle two byte header extension.
+ if (profile_id == 0xBEDE) { // OneByte extension header
+ // 0
+ // 0 1 2 3 4 5 6 7
+ // +-+-+-+-+-+-+-+-+
+ // | ID |length |
+ // +-+-+-+-+-+-+-+-+
+
+ // 0 1 2 3
+ // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ // | 0xBE | 0xDE | length=3 |
+ // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ // | ID | L=0 | data | ID | L=1 | data...
+ // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ // ...data | 0 (pad) | 0 (pad) | ID | L=3 |
+ // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ // | data |
+ // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ const uint8_t* extension_start = rtp;
+ const uint8_t* extension_end = extension_start + extension_length;
+
+ while (rtp < extension_end) {
+ const int id = (*rtp & 0xF0) >> 4;
+ const size_t length = (*rtp & 0x0F) + 1;
+ if (rtp + kOneByteExtensionHeaderLen + length > extension_end) {
+ return false;
+ }
+ // The 4-bit length is the number minus one of data bytes of this header
+ // extension element following the one-byte header.
+ if (id == extension_id) {
+ UpdateAbsSendTimeExtensionValue(rtp + kOneByteExtensionHeaderLen,
+ length, time_us);
+ found = true;
+ break;
+ }
+ rtp += kOneByteExtensionHeaderLen + length;
+ // Counting padding bytes.
+ while ((rtp < extension_end) && (*rtp == 0)) {
+ ++rtp;
+ }
+ }
+ }
+ return found;
+}
+
+bool ApplyPacketOptions(uint8_t* data,
+ size_t length,
+ const rtc::PacketTimeUpdateParams& packet_time_params,
+ uint64_t time_us) {
+ RTC_DCHECK(data);
+ RTC_DCHECK(length);
+
+ // if there is no valid |rtp_sendtime_extension_id| and |srtp_auth_key| in
+ // PacketOptions, nothing to be updated in this packet.
+ if (packet_time_params.rtp_sendtime_extension_id == -1 &&
+ packet_time_params.srtp_auth_key.empty()) {
+ return true;
+ }
+
+ // If there is a srtp auth key present then the packet must be an RTP packet.
+ // RTP packet may have been wrapped in a TURN Channel Data or TURN send
+ // indication.
+ size_t rtp_start_pos;
+ size_t rtp_length;
+ if (!UnwrapTurnPacket(data, length, &rtp_start_pos, &rtp_length)) {
+ RTC_NOTREACHED();
+ return false;
+ }
+
+ // Making sure we have a valid RTP packet at the end.
+ if (!IsRtpPacket(data + rtp_start_pos, rtp_length) ||
+ !ValidateRtpHeader(data + rtp_start_pos, rtp_length, nullptr)) {
+ RTC_NOTREACHED();
+ return false;
+ }
+
+ uint8_t* start = data + rtp_start_pos;
+ // If packet option has non default value (-1) for sendtime extension id,
+ // then we should parse the rtp packet to update the timestamp. Otherwise
+ // just calculate HMAC and update packet with it.
+ if (packet_time_params.rtp_sendtime_extension_id != -1) {
+ UpdateRtpAbsSendTimeExtension(start, rtp_length,
+ packet_time_params.rtp_sendtime_extension_id,
+ time_us);
+ }
+
+ UpdateRtpAuthTag(start, rtp_length, packet_time_params);
+ return true;
+}
+
+} // namespace cricket
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