modules/rtp_rtcp/source/ulpfec_generator_unittest.cc - src - Git at Google

 /*
  *  Copyright (c) 2012 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 <list>
 #include <memory>
 #include <utility>
 #include <vector>

 #include "modules/rtp_rtcp/source/byte_io.h"
 #include "modules/rtp_rtcp/source/fec_test_helper.h"
 #include "modules/rtp_rtcp/source/forward_error_correction.h"
 #include "modules/rtp_rtcp/source/ulpfec_generator.h"
 #include "test/gtest.h"

 namespace webrtc {

 namespace {
 using test::fec::AugmentedPacket;
 using test::fec::AugmentedPacketGenerator;

 constexpr int kFecPayloadType = 96;
 constexpr int kRedPayloadType = 97;
 constexpr uint32_t kMediaSsrc = 835424;
 }  // namespace

 void VerifyHeader(uint16_t seq_num,
                   uint32_t timestamp,
                   int red_payload_type,
                   int fec_payload_type,
                   RedPacket* packet,
                   bool marker_bit) {
   EXPECT_GT(packet->length(), kRtpHeaderSize);
   EXPECT_TRUE(packet->data() != NULL);
   uint8_t* data = packet->data();
   // Marker bit not set.
   EXPECT_EQ(marker_bit ? 0x80 : 0, data[1] & 0x80);
   EXPECT_EQ(red_payload_type, data[1] & 0x7F);
   EXPECT_EQ(seq_num, (data[2] << 8) + data[3]);
   uint32_t parsed_timestamp =
       (data[4] << 24) + (data[5] << 16) + (data[6] << 8) + data[7];
   EXPECT_EQ(timestamp, parsed_timestamp);
   EXPECT_EQ(static_cast<uint8_t>(fec_payload_type), data[kRtpHeaderSize]);
 }

 class UlpfecGeneratorTest : public ::testing::Test {
  protected:
   UlpfecGeneratorTest() : packet_generator_(kMediaSsrc) {}

   UlpfecGenerator ulpfec_generator_;
   AugmentedPacketGenerator packet_generator_;
 };

 // Verifies bug found via fuzzing, where a gap in the packet sequence caused us
 // to move past the end of the current FEC packet mask byte without moving to
 // the next byte. That likely caused us to repeatedly read from the same byte,
 // and if that byte didn't protect packets we would generate empty FEC.
 TEST_F(UlpfecGeneratorTest, NoEmptyFecWithSeqNumGaps) {
   struct Packet {
     size_t header_size;
     size_t payload_size;
     uint16_t seq_num;
     bool marker_bit;
   };
   std::vector<Packet> protected_packets;
   protected_packets.push_back({15, 3, 41, 0});
   protected_packets.push_back({14, 1, 43, 0});
   protected_packets.push_back({19, 0, 48, 0});
   protected_packets.push_back({19, 0, 50, 0});
   protected_packets.push_back({14, 3, 51, 0});
   protected_packets.push_back({13, 8, 52, 0});
   protected_packets.push_back({19, 2, 53, 0});
   protected_packets.push_back({12, 3, 54, 0});
   protected_packets.push_back({21, 0, 55, 0});
   protected_packets.push_back({13, 3, 57, 1});
   FecProtectionParams params = {117, 3, kFecMaskBursty};
   ulpfec_generator_.SetFecParameters(params);
   uint8_t packet[28] = {0};
   for (Packet p : protected_packets) {
     if (p.marker_bit) {
       packet[1] |= 0x80;
     } else {
       packet[1] &= ~0x80;
     }
     ByteWriter<uint16_t>::WriteBigEndian(&packet[2], p.seq_num);
     ulpfec_generator_.AddRtpPacketAndGenerateFec(packet, p.payload_size,
                                                  p.header_size);
     size_t num_fec_packets = ulpfec_generator_.NumAvailableFecPackets();
     if (num_fec_packets > 0) {
       std::vector<std::unique_ptr<RedPacket>> fec_packets =
           ulpfec_generator_.GetUlpfecPacketsAsRed(kRedPayloadType,
                                                   kFecPayloadType, 100);
       EXPECT_EQ(num_fec_packets, fec_packets.size());
     }
   }
 }

 TEST_F(UlpfecGeneratorTest, OneFrameFec) {
   // The number of media packets (|kNumPackets|), number of frames (one for
   // this test), and the protection factor (|params->fec_rate|) are set to make
   // sure the conditions for generating FEC are satisfied. This means:
   // (1) protection factor is high enough so that actual overhead over 1 frame
   // of packets is within |kMaxExcessOverhead|, and (2) the total number of
   // media packets for 1 frame is at least |minimum_media_packets_fec_|.
   constexpr size_t kNumPackets = 4;
   FecProtectionParams params = {15, 3, kFecMaskRandom};
   packet_generator_.NewFrame(kNumPackets);
   ulpfec_generator_.SetFecParameters(params);  // Expecting one FEC packet.
   uint32_t last_timestamp = 0;
   for (size_t i = 0; i < kNumPackets; ++i) {
     std::unique_ptr<AugmentedPacket> packet =
         packet_generator_.NextPacket(i, 10);
     EXPECT_EQ(0, ulpfec_generator_.AddRtpPacketAndGenerateFec(
                      packet->data, packet->length, kRtpHeaderSize));
     last_timestamp = packet->header.timestamp;
   }
   EXPECT_TRUE(ulpfec_generator_.FecAvailable());
   const uint16_t seq_num = packet_generator_.NextPacketSeqNum();
   std::vector<std::unique_ptr<RedPacket>> red_packets =
       ulpfec_generator_.GetUlpfecPacketsAsRed(kRedPayloadType, kFecPayloadType,
                                               seq_num);
   EXPECT_FALSE(ulpfec_generator_.FecAvailable());
   ASSERT_EQ(1u, red_packets.size());
   VerifyHeader(seq_num, last_timestamp, kRedPayloadType, kFecPayloadType,
                red_packets.front().get(), false);
 }

 TEST_F(UlpfecGeneratorTest, TwoFrameFec) {
   // The number of media packets/frame (|kNumPackets|), the number of frames
   // (|kNumFrames|), and the protection factor (|params->fec_rate|) are set to
   // make sure the conditions for generating FEC are satisfied. This means:
   // (1) protection factor is high enough so that actual overhead over
   // |kNumFrames| is within |kMaxExcessOverhead|, and (2) the total number of
   // media packets for |kNumFrames| frames is at least
   // |minimum_media_packets_fec_|.
   constexpr size_t kNumPackets = 2;
   constexpr size_t kNumFrames = 2;

   FecProtectionParams params = {15, 3, kFecMaskRandom};
   ulpfec_generator_.SetFecParameters(params);  // Expecting one FEC packet.
   uint32_t last_timestamp = 0;
   for (size_t i = 0; i < kNumFrames; ++i) {
     packet_generator_.NewFrame(kNumPackets);
     for (size_t j = 0; j < kNumPackets; ++j) {
       std::unique_ptr<AugmentedPacket> packet =
           packet_generator_.NextPacket(i * kNumPackets + j, 10);
       EXPECT_EQ(0, ulpfec_generator_.AddRtpPacketAndGenerateFec(
                        packet->data, packet->length, kRtpHeaderSize));
       last_timestamp = packet->header.timestamp;
     }
   }
   EXPECT_TRUE(ulpfec_generator_.FecAvailable());
   const uint16_t seq_num = packet_generator_.NextPacketSeqNum();
   std::vector<std::unique_ptr<RedPacket>> red_packets =
       ulpfec_generator_.GetUlpfecPacketsAsRed(kRedPayloadType, kFecPayloadType,
                                               seq_num);
   EXPECT_FALSE(ulpfec_generator_.FecAvailable());
   ASSERT_EQ(1u, red_packets.size());
   VerifyHeader(seq_num, last_timestamp, kRedPayloadType, kFecPayloadType,
                red_packets.front().get(), false);
 }

 TEST_F(UlpfecGeneratorTest, MixedMediaRtpHeaderLengths) {
   constexpr size_t kShortRtpHeaderLength = 12;
   constexpr size_t kLongRtpHeaderLength = 16;

   // Only one frame required to generate FEC.
   FecProtectionParams params = {127, 1, kFecMaskRandom};
   ulpfec_generator_.SetFecParameters(params);

   // Fill up internal buffer with media packets with short RTP header length.
   packet_generator_.NewFrame(kUlpfecMaxMediaPackets + 1);
   for (size_t i = 0; i < kUlpfecMaxMediaPackets; ++i) {
     std::unique_ptr<AugmentedPacket> packet =
         packet_generator_.NextPacket(i, 10);
     EXPECT_EQ(0, ulpfec_generator_.AddRtpPacketAndGenerateFec(
                      packet->data, packet->length, kShortRtpHeaderLength));
     EXPECT_FALSE(ulpfec_generator_.FecAvailable());
   }

   // Kick off FEC generation with media packet with long RTP header length.
   // Since the internal buffer is full, this packet will not be protected.
   std::unique_ptr<AugmentedPacket> packet =
       packet_generator_.NextPacket(kUlpfecMaxMediaPackets, 10);
   EXPECT_EQ(0, ulpfec_generator_.AddRtpPacketAndGenerateFec(
                    packet->data, packet->length, kLongRtpHeaderLength));
   EXPECT_TRUE(ulpfec_generator_.FecAvailable());

   // Ensure that the RED header is placed correctly, i.e. the correct
   // RTP header length was used in the RED packet creation.
   const uint16_t seq_num = packet_generator_.NextPacketSeqNum();
   std::vector<std::unique_ptr<RedPacket>> red_packets =
       ulpfec_generator_.GetUlpfecPacketsAsRed(kRedPayloadType, kFecPayloadType,
                                               seq_num);
   for (const auto& red_packet : red_packets) {
     EXPECT_EQ(kFecPayloadType, red_packet->data()[kShortRtpHeaderLength]);
   }
 }

 }  // namespace webrtc
	/*
	* Copyright (c) 2012 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 <list>
	#include <memory>
	#include <utility>
	#include <vector>

	#include "modules/rtp_rtcp/source/byte_io.h"
	#include "modules/rtp_rtcp/source/fec_test_helper.h"
	#include "modules/rtp_rtcp/source/forward_error_correction.h"
	#include "modules/rtp_rtcp/source/ulpfec_generator.h"
	#include "test/gtest.h"

	namespace webrtc {

	namespace {
	using test::fec::AugmentedPacket;
	using test::fec::AugmentedPacketGenerator;

	constexpr int kFecPayloadType = 96;
	constexpr int kRedPayloadType = 97;
	constexpr uint32_t kMediaSsrc = 835424;
	} // namespace

	void VerifyHeader(uint16_t seq_num,
	uint32_t timestamp,
	int red_payload_type,
	int fec_payload_type,
	RedPacket* packet,
	bool marker_bit) {
	EXPECT_GT(packet->length(), kRtpHeaderSize);
	EXPECT_TRUE(packet->data() != NULL);
	uint8_t* data = packet->data();
	// Marker bit not set.
	EXPECT_EQ(marker_bit ? 0x80 : 0, data[1] & 0x80);
	EXPECT_EQ(red_payload_type, data[1] & 0x7F);
	EXPECT_EQ(seq_num, (data[2] << 8) + data[3]);
	uint32_t parsed_timestamp =
	(data[4] << 24) + (data[5] << 16) + (data[6] << 8) + data[7];
	EXPECT_EQ(timestamp, parsed_timestamp);
	EXPECT_EQ(static_cast<uint8_t>(fec_payload_type), data[kRtpHeaderSize]);
	}

	class UlpfecGeneratorTest : public ::testing::Test {
	protected:
	UlpfecGeneratorTest() : packet_generator_(kMediaSsrc) {}

	UlpfecGenerator ulpfec_generator_;
	AugmentedPacketGenerator packet_generator_;
	};

	// Verifies bug found via fuzzing, where a gap in the packet sequence caused us
	// to move past the end of the current FEC packet mask byte without moving to
	// the next byte. That likely caused us to repeatedly read from the same byte,
	// and if that byte didn't protect packets we would generate empty FEC.
	TEST_F(UlpfecGeneratorTest, NoEmptyFecWithSeqNumGaps) {
	struct Packet {
	size_t header_size;
	size_t payload_size;
	uint16_t seq_num;
	bool marker_bit;
	};
	std::vector<Packet> protected_packets;
	protected_packets.push_back({15, 3, 41, 0});
	protected_packets.push_back({14, 1, 43, 0});
	protected_packets.push_back({19, 0, 48, 0});
	protected_packets.push_back({19, 0, 50, 0});
	protected_packets.push_back({14, 3, 51, 0});
	protected_packets.push_back({13, 8, 52, 0});
	protected_packets.push_back({19, 2, 53, 0});
	protected_packets.push_back({12, 3, 54, 0});
	protected_packets.push_back({21, 0, 55, 0});
	protected_packets.push_back({13, 3, 57, 1});
	FecProtectionParams params = {117, 3, kFecMaskBursty};
	ulpfec_generator_.SetFecParameters(params);
	uint8_t packet[28] = {0};
	for (Packet p : protected_packets) {
	if (p.marker_bit) {
	packet[1] \|= 0x80;
	} else {
	packet[1] &= ~0x80;
	}
	ByteWriter<uint16_t>::WriteBigEndian(&packet[2], p.seq_num);
	ulpfec_generator_.AddRtpPacketAndGenerateFec(packet, p.payload_size,
	p.header_size);
	size_t num_fec_packets = ulpfec_generator_.NumAvailableFecPackets();
	if (num_fec_packets > 0) {
	std::vector<std::unique_ptr<RedPacket>> fec_packets =
	ulpfec_generator_.GetUlpfecPacketsAsRed(kRedPayloadType,
	kFecPayloadType, 100);
	EXPECT_EQ(num_fec_packets, fec_packets.size());
	}
	}
	}

	TEST_F(UlpfecGeneratorTest, OneFrameFec) {
	// The number of media packets (\|kNumPackets\|), number of frames (one for
	// this test), and the protection factor (\|params->fec_rate\|) are set to make
	// sure the conditions for generating FEC are satisfied. This means:
	// (1) protection factor is high enough so that actual overhead over 1 frame
	// of packets is within \|kMaxExcessOverhead\|, and (2) the total number of
	// media packets for 1 frame is at least \|minimum_media_packets_fec_\|.
	constexpr size_t kNumPackets = 4;
	FecProtectionParams params = {15, 3, kFecMaskRandom};
	packet_generator_.NewFrame(kNumPackets);
	ulpfec_generator_.SetFecParameters(params); // Expecting one FEC packet.
	uint32_t last_timestamp = 0;
	for (size_t i = 0; i < kNumPackets; ++i) {
	std::unique_ptr<AugmentedPacket> packet =
	packet_generator_.NextPacket(i, 10);
	EXPECT_EQ(0, ulpfec_generator_.AddRtpPacketAndGenerateFec(
	packet->data, packet->length, kRtpHeaderSize));
	last_timestamp = packet->header.timestamp;
	}
	EXPECT_TRUE(ulpfec_generator_.FecAvailable());
	const uint16_t seq_num = packet_generator_.NextPacketSeqNum();
	std::vector<std::unique_ptr<RedPacket>> red_packets =
	ulpfec_generator_.GetUlpfecPacketsAsRed(kRedPayloadType, kFecPayloadType,
	seq_num);
	EXPECT_FALSE(ulpfec_generator_.FecAvailable());
	ASSERT_EQ(1u, red_packets.size());
	VerifyHeader(seq_num, last_timestamp, kRedPayloadType, kFecPayloadType,
	red_packets.front().get(), false);
	}

	TEST_F(UlpfecGeneratorTest, TwoFrameFec) {
	// The number of media packets/frame (\|kNumPackets\|), the number of frames
	// (\|kNumFrames\|), and the protection factor (\|params->fec_rate\|) are set to
	// make sure the conditions for generating FEC are satisfied. This means:
	// (1) protection factor is high enough so that actual overhead over
	// \|kNumFrames\| is within \|kMaxExcessOverhead\|, and (2) the total number of
	// media packets for \|kNumFrames\| frames is at least
	// \|minimum_media_packets_fec_\|.
	constexpr size_t kNumPackets = 2;
	constexpr size_t kNumFrames = 2;

	FecProtectionParams params = {15, 3, kFecMaskRandom};
	ulpfec_generator_.SetFecParameters(params); // Expecting one FEC packet.
	uint32_t last_timestamp = 0;
	for (size_t i = 0; i < kNumFrames; ++i) {
	packet_generator_.NewFrame(kNumPackets);
	for (size_t j = 0; j < kNumPackets; ++j) {
	std::unique_ptr<AugmentedPacket> packet =
	packet_generator_.NextPacket(i * kNumPackets + j, 10);
	EXPECT_EQ(0, ulpfec_generator_.AddRtpPacketAndGenerateFec(
	packet->data, packet->length, kRtpHeaderSize));
	last_timestamp = packet->header.timestamp;
	}
	}
	EXPECT_TRUE(ulpfec_generator_.FecAvailable());
	const uint16_t seq_num = packet_generator_.NextPacketSeqNum();
	std::vector<std::unique_ptr<RedPacket>> red_packets =
	ulpfec_generator_.GetUlpfecPacketsAsRed(kRedPayloadType, kFecPayloadType,
	seq_num);
	EXPECT_FALSE(ulpfec_generator_.FecAvailable());
	ASSERT_EQ(1u, red_packets.size());
	VerifyHeader(seq_num, last_timestamp, kRedPayloadType, kFecPayloadType,
	red_packets.front().get(), false);
	}

	TEST_F(UlpfecGeneratorTest, MixedMediaRtpHeaderLengths) {
	constexpr size_t kShortRtpHeaderLength = 12;
	constexpr size_t kLongRtpHeaderLength = 16;

	// Only one frame required to generate FEC.
	FecProtectionParams params = {127, 1, kFecMaskRandom};
	ulpfec_generator_.SetFecParameters(params);

	// Fill up internal buffer with media packets with short RTP header length.
	packet_generator_.NewFrame(kUlpfecMaxMediaPackets + 1);
	for (size_t i = 0; i < kUlpfecMaxMediaPackets; ++i) {
	std::unique_ptr<AugmentedPacket> packet =
	packet_generator_.NextPacket(i, 10);
	EXPECT_EQ(0, ulpfec_generator_.AddRtpPacketAndGenerateFec(
	packet->data, packet->length, kShortRtpHeaderLength));
	EXPECT_FALSE(ulpfec_generator_.FecAvailable());
	}

	// Kick off FEC generation with media packet with long RTP header length.
	// Since the internal buffer is full, this packet will not be protected.
	std::unique_ptr<AugmentedPacket> packet =
	packet_generator_.NextPacket(kUlpfecMaxMediaPackets, 10);
	EXPECT_EQ(0, ulpfec_generator_.AddRtpPacketAndGenerateFec(
	packet->data, packet->length, kLongRtpHeaderLength));
	EXPECT_TRUE(ulpfec_generator_.FecAvailable());

	// Ensure that the RED header is placed correctly, i.e. the correct
	// RTP header length was used in the RED packet creation.
	const uint16_t seq_num = packet_generator_.NextPacketSeqNum();
	std::vector<std::unique_ptr<RedPacket>> red_packets =
	ulpfec_generator_.GetUlpfecPacketsAsRed(kRedPayloadType, kFecPayloadType,
	seq_num);
	for (const auto& red_packet : red_packets) {
	EXPECT_EQ(kFecPayloadType, red_packet->data()[kShortRtpHeaderLength]);
	}
	}

	} // namespace webrtc