net/dcsctp/rx/reassembly_queue_test.cc - src - Git at Google

 /*
  *  Copyright (c) 2021 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 "net/dcsctp/rx/reassembly_queue.h"

 #include <stddef.h>

 #include <algorithm>
 #include <array>
 #include <cstdint>
 #include <iterator>
 #include <vector>

 #include "api/array_view.h"
 #include "net/dcsctp/common/handover_testing.h"
 #include "net/dcsctp/packet/chunk/forward_tsn_chunk.h"
 #include "net/dcsctp/packet/chunk/forward_tsn_common.h"
 #include "net/dcsctp/packet/chunk/iforward_tsn_chunk.h"
 #include "net/dcsctp/packet/data.h"
 #include "net/dcsctp/public/dcsctp_message.h"
 #include "net/dcsctp/public/types.h"
 #include "net/dcsctp/testing/data_generator.h"
 #include "rtc_base/gunit.h"
 #include "test/gmock.h"

 namespace dcsctp {
 namespace {
 using ::testing::ElementsAre;
 using ::testing::SizeIs;
 using ::testing::UnorderedElementsAre;

 // The default maximum size of the Reassembly Queue.
 static constexpr size_t kBufferSize = 10000;

 static constexpr StreamID kStreamID(1);
 static constexpr SSN kSSN(0);
 static constexpr MID kMID(0);
 static constexpr FSN kFSN(0);
 static constexpr PPID kPPID(53);

 static constexpr std::array<uint8_t, 4> kShortPayload = {1, 2, 3, 4};
 static constexpr std::array<uint8_t, 4> kMessage2Payload = {5, 6, 7, 8};
 static constexpr std::array<uint8_t, 6> kSixBytePayload = {1, 2, 3, 4, 5, 6};
 static constexpr std::array<uint8_t, 8> kMediumPayload1 = {1, 2, 3, 4,
                                                            5, 6, 7, 8};
 static constexpr std::array<uint8_t, 8> kMediumPayload2 = {9,  10, 11, 12,
                                                            13, 14, 15, 16};
 static constexpr std::array<uint8_t, 16> kLongPayload = {
     1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16};

 MATCHER_P3(SctpMessageIs, stream_id, ppid, expected_payload, "") {
   if (arg.stream_id() != stream_id) {
     *result_listener << "the stream_id is " << *arg.stream_id();
     return false;
   }

   if (arg.ppid() != ppid) {
     *result_listener << "the ppid is " << *arg.ppid();
     return false;
   }

   if (std::vector<uint8_t>(arg.payload().begin(), arg.payload().end()) !=
       std::vector<uint8_t>(expected_payload.begin(), expected_payload.end())) {
     *result_listener << "the payload is wrong";
     return false;
   }
   return true;
 }

 class ReassemblyQueueTest : public testing::Test {
  protected:
   ReassemblyQueueTest() {}
   DataGenerator gen_;
 };

 TEST_F(ReassemblyQueueTest, EmptyQueue) {
   ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
   EXPECT_FALSE(reasm.HasMessages());
   EXPECT_EQ(reasm.queued_bytes(), 0u);
 }

 TEST_F(ReassemblyQueueTest, SingleUnorderedChunkMessage) {
   ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
   reasm.Add(TSN(10), gen_.Unordered({1, 2, 3, 4}, "BE"));
   EXPECT_TRUE(reasm.HasMessages());
   EXPECT_THAT(reasm.FlushMessages(),
               ElementsAre(SctpMessageIs(kStreamID, kPPID, kShortPayload)));
   EXPECT_EQ(reasm.queued_bytes(), 0u);
 }

 TEST_F(ReassemblyQueueTest, LargeUnorderedChunkAllPermutations) {
   std::vector<uint32_t> tsns = {10, 11, 12, 13};
   rtc::ArrayView<const uint8_t> payload(kLongPayload);
   do {
     ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);

     for (size_t i = 0; i < tsns.size(); i++) {
       auto span = payload.subview((tsns[i] - 10) * 4, 4);
       Data::IsBeginning is_beginning(tsns[i] == 10);
       Data::IsEnd is_end(tsns[i] == 13);

       reasm.Add(TSN(tsns[i]),
                 Data(kStreamID, kSSN, kMID, kFSN, kPPID,
                      std::vector<uint8_t>(span.begin(), span.end()),
                      is_beginning, is_end, IsUnordered(false)));
       if (i < 3) {
         EXPECT_FALSE(reasm.HasMessages());
       } else {
         EXPECT_TRUE(reasm.HasMessages());
         EXPECT_THAT(reasm.FlushMessages(),
                     ElementsAre(SctpMessageIs(kStreamID, kPPID, kLongPayload)));
         EXPECT_EQ(reasm.queued_bytes(), 0u);
       }
     }
   } while (std::next_permutation(std::begin(tsns), std::end(tsns)));
 }

 TEST_F(ReassemblyQueueTest, SingleOrderedChunkMessage) {
   ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
   reasm.Add(TSN(10), gen_.Ordered({1, 2, 3, 4}, "BE"));
   EXPECT_EQ(reasm.queued_bytes(), 0u);
   EXPECT_TRUE(reasm.HasMessages());
   EXPECT_THAT(reasm.FlushMessages(),
               ElementsAre(SctpMessageIs(kStreamID, kPPID, kShortPayload)));
 }

 TEST_F(ReassemblyQueueTest, ManySmallOrderedMessages) {
   std::vector<uint32_t> tsns = {10, 11, 12, 13};
   rtc::ArrayView<const uint8_t> payload(kLongPayload);
   do {
     ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
     for (size_t i = 0; i < tsns.size(); i++) {
       auto span = payload.subview((tsns[i] - 10) * 4, 4);
       Data::IsBeginning is_beginning(true);
       Data::IsEnd is_end(true);

       SSN ssn(static_cast<uint16_t>(tsns[i] - 10));
       reasm.Add(TSN(tsns[i]),
                 Data(kStreamID, ssn, kMID, kFSN, kPPID,
                      std::vector<uint8_t>(span.begin(), span.end()),
                      is_beginning, is_end, IsUnordered(false)));
     }
     EXPECT_THAT(
         reasm.FlushMessages(),
         ElementsAre(SctpMessageIs(kStreamID, kPPID, payload.subview(0, 4)),
                     SctpMessageIs(kStreamID, kPPID, payload.subview(4, 4)),
                     SctpMessageIs(kStreamID, kPPID, payload.subview(8, 4)),
                     SctpMessageIs(kStreamID, kPPID, payload.subview(12, 4))));
     EXPECT_EQ(reasm.queued_bytes(), 0u);
   } while (std::next_permutation(std::begin(tsns), std::end(tsns)));
 }

 TEST_F(ReassemblyQueueTest, RetransmissionInLargeOrdered) {
   ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
   reasm.Add(TSN(10), gen_.Ordered({1}, "B"));
   reasm.Add(TSN(12), gen_.Ordered({3}));
   reasm.Add(TSN(13), gen_.Ordered({4}));
   reasm.Add(TSN(14), gen_.Ordered({5}));
   reasm.Add(TSN(15), gen_.Ordered({6}));
   reasm.Add(TSN(16), gen_.Ordered({7}));
   reasm.Add(TSN(17), gen_.Ordered({8}));
   EXPECT_EQ(reasm.queued_bytes(), 7u);

   // lost and retransmitted
   reasm.Add(TSN(11), gen_.Ordered({2}));
   reasm.Add(TSN(18), gen_.Ordered({9}));
   reasm.Add(TSN(19), gen_.Ordered({10}));
   EXPECT_EQ(reasm.queued_bytes(), 10u);
   EXPECT_FALSE(reasm.HasMessages());

   reasm.Add(TSN(20), gen_.Ordered({11, 12, 13, 14, 15, 16}, "E"));
   EXPECT_TRUE(reasm.HasMessages());
   EXPECT_THAT(reasm.FlushMessages(),
               ElementsAre(SctpMessageIs(kStreamID, kPPID, kLongPayload)));
   EXPECT_EQ(reasm.queued_bytes(), 0u);
 }

 TEST_F(ReassemblyQueueTest, ForwardTSNRemoveUnordered) {
   ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
   reasm.Add(TSN(10), gen_.Unordered({1}, "B"));
   reasm.Add(TSN(12), gen_.Unordered({3}));
   reasm.Add(TSN(13), gen_.Unordered({4}, "E"));

   reasm.Add(TSN(14), gen_.Unordered({5}, "B"));
   reasm.Add(TSN(15), gen_.Unordered({6}));
   reasm.Add(TSN(17), gen_.Unordered({8}, "E"));
   EXPECT_EQ(reasm.queued_bytes(), 6u);

   EXPECT_FALSE(reasm.HasMessages());

   reasm.Handle(ForwardTsnChunk(TSN(13), {}));
   EXPECT_EQ(reasm.queued_bytes(), 3u);

   // The lost chunk comes, but too late.
   reasm.Add(TSN(11), gen_.Unordered({2}));
   EXPECT_FALSE(reasm.HasMessages());
   EXPECT_EQ(reasm.queued_bytes(), 3u);

   // The second lost chunk comes, message is assembled.
   reasm.Add(TSN(16), gen_.Unordered({7}));
   EXPECT_TRUE(reasm.HasMessages());
   EXPECT_EQ(reasm.queued_bytes(), 0u);
 }

 TEST_F(ReassemblyQueueTest, ForwardTSNRemoveOrdered) {
   ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
   reasm.Add(TSN(10), gen_.Ordered({1}, "B"));
   reasm.Add(TSN(12), gen_.Ordered({3}));
   reasm.Add(TSN(13), gen_.Ordered({4}, "E"));

   reasm.Add(TSN(14), gen_.Ordered({5}, "B"));
   reasm.Add(TSN(15), gen_.Ordered({6}));
   reasm.Add(TSN(16), gen_.Ordered({7}));
   reasm.Add(TSN(17), gen_.Ordered({8}, "E"));
   EXPECT_EQ(reasm.queued_bytes(), 7u);

   EXPECT_FALSE(reasm.HasMessages());

   reasm.Handle(ForwardTsnChunk(
       TSN(13), {ForwardTsnChunk::SkippedStream(kStreamID, kSSN)}));
   EXPECT_EQ(reasm.queued_bytes(), 0u);

   // The lost chunk comes, but too late.
   EXPECT_TRUE(reasm.HasMessages());
   EXPECT_THAT(reasm.FlushMessages(),
               ElementsAre(SctpMessageIs(kStreamID, kPPID, kMessage2Payload)));
 }

 TEST_F(ReassemblyQueueTest, ForwardTSNRemoveALotOrdered) {
   ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
   reasm.Add(TSN(10), gen_.Ordered({1}, "B"));
   reasm.Add(TSN(12), gen_.Ordered({3}));
   reasm.Add(TSN(13), gen_.Ordered({4}, "E"));

   reasm.Add(TSN(15), gen_.Ordered({5}, "B"));
   reasm.Add(TSN(16), gen_.Ordered({6}));
   reasm.Add(TSN(17), gen_.Ordered({7}));
   reasm.Add(TSN(18), gen_.Ordered({8}, "E"));
   EXPECT_EQ(reasm.queued_bytes(), 7u);

   EXPECT_FALSE(reasm.HasMessages());

   reasm.Handle(ForwardTsnChunk(
       TSN(13), {ForwardTsnChunk::SkippedStream(kStreamID, kSSN)}));
   EXPECT_EQ(reasm.queued_bytes(), 0u);

   // The lost chunk comes, but too late.
   EXPECT_TRUE(reasm.HasMessages());
   EXPECT_THAT(reasm.FlushMessages(),
               ElementsAre(SctpMessageIs(kStreamID, kPPID, kMessage2Payload)));
 }

 TEST_F(ReassemblyQueueTest, ShouldntDeliverMessagesBeforeInitialTsn) {
   ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
   reasm.Add(TSN(5), gen_.Unordered({1, 2, 3, 4}, "BE"));
   EXPECT_EQ(reasm.queued_bytes(), 0u);
   EXPECT_FALSE(reasm.HasMessages());
 }

 TEST_F(ReassemblyQueueTest, ShouldntRedeliverUnorderedMessages) {
   ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
   reasm.Add(TSN(10), gen_.Unordered({1, 2, 3, 4}, "BE"));
   EXPECT_EQ(reasm.queued_bytes(), 0u);
   EXPECT_TRUE(reasm.HasMessages());
   EXPECT_THAT(reasm.FlushMessages(),
               ElementsAre(SctpMessageIs(kStreamID, kPPID, kShortPayload)));
   reasm.Add(TSN(10), gen_.Unordered({1, 2, 3, 4}, "BE"));
   EXPECT_EQ(reasm.queued_bytes(), 0u);
   EXPECT_FALSE(reasm.HasMessages());
 }

 TEST_F(ReassemblyQueueTest, ShouldntRedeliverUnorderedMessagesReallyUnordered) {
   ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
   reasm.Add(TSN(10), gen_.Unordered({1, 2, 3, 4}, "B"));
   EXPECT_EQ(reasm.queued_bytes(), 4u);

   EXPECT_FALSE(reasm.HasMessages());

   reasm.Add(TSN(12), gen_.Unordered({1, 2, 3, 4}, "BE"));
   EXPECT_EQ(reasm.queued_bytes(), 4u);
   EXPECT_TRUE(reasm.HasMessages());

   EXPECT_THAT(reasm.FlushMessages(),
               ElementsAre(SctpMessageIs(kStreamID, kPPID, kShortPayload)));
   reasm.Add(TSN(12), gen_.Unordered({1, 2, 3, 4}, "BE"));
   EXPECT_EQ(reasm.queued_bytes(), 4u);
   EXPECT_FALSE(reasm.HasMessages());
 }

 TEST_F(ReassemblyQueueTest, ShouldntDeliverBeforeForwardedTsn) {
   ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
   reasm.Handle(ForwardTsnChunk(TSN(12), {}));

   reasm.Add(TSN(12), gen_.Unordered({1, 2, 3, 4}, "BE"));
   EXPECT_EQ(reasm.queued_bytes(), 0u);
   EXPECT_FALSE(reasm.HasMessages());
 }

 TEST_F(ReassemblyQueueTest, NotReadyForHandoverWhenDeliveredTsnsHaveGap) {
   ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
   reasm.Add(TSN(10), gen_.Unordered({1, 2, 3, 4}, "B"));
   EXPECT_FALSE(reasm.HasMessages());

   reasm.Add(TSN(12), gen_.Unordered({1, 2, 3, 4}, "BE"));
   EXPECT_TRUE(reasm.HasMessages());
   EXPECT_EQ(
       reasm.GetHandoverReadiness(),
       HandoverReadinessStatus()
           .Add(HandoverUnreadinessReason::kReassemblyQueueDeliveredTSNsGap)
           .Add(
               HandoverUnreadinessReason::kUnorderedStreamHasUnassembledChunks));

   EXPECT_THAT(reasm.FlushMessages(),
               ElementsAre(SctpMessageIs(kStreamID, kPPID, kShortPayload)));
   EXPECT_EQ(
       reasm.GetHandoverReadiness(),
       HandoverReadinessStatus()
           .Add(HandoverUnreadinessReason::kReassemblyQueueDeliveredTSNsGap)
           .Add(
               HandoverUnreadinessReason::kUnorderedStreamHasUnassembledChunks));

   reasm.Handle(ForwardTsnChunk(TSN(13), {}));
   EXPECT_EQ(reasm.GetHandoverReadiness(), HandoverReadinessStatus());
 }

 TEST_F(ReassemblyQueueTest, NotReadyForHandoverWhenResetStreamIsDeferred) {
   ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
   DataGeneratorOptions opts;
   opts.message_id = MID(0);
   reasm.Add(TSN(10), gen_.Ordered({1, 2, 3, 4}, "BE", opts));
   opts.message_id = MID(1);
   reasm.Add(TSN(11), gen_.Ordered({1, 2, 3, 4}, "BE", opts));
   EXPECT_THAT(reasm.FlushMessages(), SizeIs(2));

   reasm.ResetStreams(
       OutgoingSSNResetRequestParameter(
           ReconfigRequestSN(10), ReconfigRequestSN(3), TSN(13), {StreamID(1)}),
       TSN(11));
   EXPECT_EQ(reasm.GetHandoverReadiness(),
             HandoverReadinessStatus().Add(
                 HandoverUnreadinessReason::kStreamResetDeferred));

   opts.message_id = MID(3);
   opts.ppid = PPID(3);
   reasm.Add(TSN(13), gen_.Ordered({1, 2, 3, 4}, "BE", opts));
   reasm.MaybeResetStreamsDeferred(TSN(11));

   opts.message_id = MID(2);
   opts.ppid = PPID(2);
   reasm.Add(TSN(13), gen_.Ordered({1, 2, 3, 4}, "BE", opts));
   reasm.MaybeResetStreamsDeferred(TSN(15));
   EXPECT_EQ(reasm.GetHandoverReadiness(),
             HandoverReadinessStatus().Add(
                 HandoverUnreadinessReason::kReassemblyQueueDeliveredTSNsGap));

   EXPECT_THAT(reasm.FlushMessages(), SizeIs(2));
   EXPECT_EQ(reasm.GetHandoverReadiness(),
             HandoverReadinessStatus().Add(
                 HandoverUnreadinessReason::kReassemblyQueueDeliveredTSNsGap));

   reasm.Handle(ForwardTsnChunk(TSN(15), {}));
   EXPECT_EQ(reasm.GetHandoverReadiness(), HandoverReadinessStatus());
 }

 TEST_F(ReassemblyQueueTest, HandoverInInitialState) {
   ReassemblyQueue reasm1("log: ", TSN(10), kBufferSize);

   EXPECT_EQ(reasm1.GetHandoverReadiness(), HandoverReadinessStatus());
   DcSctpSocketHandoverState state;
   reasm1.AddHandoverState(state);
   g_handover_state_transformer_for_test(&state);
   ReassemblyQueue reasm2("log: ", TSN(100), kBufferSize,
                          /*use_message_interleaving=*/false);
   reasm2.RestoreFromState(state);

   reasm2.Add(TSN(10), gen_.Ordered({1, 2, 3, 4}, "BE"));
   EXPECT_THAT(reasm2.FlushMessages(), SizeIs(1));
 }

 TEST_F(ReassemblyQueueTest, HandoverAfterHavingAssembedOneMessage) {
   ReassemblyQueue reasm1("log: ", TSN(10), kBufferSize);
   reasm1.Add(TSN(10), gen_.Ordered({1, 2, 3, 4}, "BE"));
   EXPECT_THAT(reasm1.FlushMessages(), SizeIs(1));

   EXPECT_EQ(reasm1.GetHandoverReadiness(), HandoverReadinessStatus());
   DcSctpSocketHandoverState state;
   reasm1.AddHandoverState(state);
   g_handover_state_transformer_for_test(&state);
   ReassemblyQueue reasm2("log: ", TSN(100), kBufferSize,
                          /*use_message_interleaving=*/false);
   reasm2.RestoreFromState(state);

   reasm2.Add(TSN(11), gen_.Ordered({1, 2, 3, 4}, "BE"));
   EXPECT_THAT(reasm2.FlushMessages(), SizeIs(1));
 }

 TEST_F(ReassemblyQueueTest, HandleInconsistentForwardTSN) {
   // Found when fuzzing.
   ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
   // Add TSN=43, SSN=7. Can't be reassembled as previous SSNs aren't known.
   reasm.Add(TSN(43), Data(kStreamID, SSN(7), MID(0), FSN(0), kPPID,
                           std::vector<uint8_t>(10), Data::IsBeginning(true),
                           Data::IsEnd(true), IsUnordered(false)));

   // Invalid, as TSN=44 have to have SSN>=7, but peer says 6.
   reasm.Handle(ForwardTsnChunk(
       TSN(44), {ForwardTsnChunk::SkippedStream(kStreamID, SSN(6))}));

   // Don't assemble SSN=7, as that TSN is skipped.
   EXPECT_FALSE(reasm.HasMessages());
 }

 TEST_F(ReassemblyQueueTest, SingleUnorderedChunkMessageInRfc8260) {
   ReassemblyQueue reasm("log: ", TSN(10), kBufferSize,
                         /*use_message_interleaving=*/true);
   reasm.Add(TSN(10), Data(StreamID(1), SSN(0), MID(0), FSN(0), kPPID,
                           {1, 2, 3, 4}, Data::IsBeginning(true),
                           Data::IsEnd(true), IsUnordered(true)));
   EXPECT_EQ(reasm.queued_bytes(), 0u);
   EXPECT_TRUE(reasm.HasMessages());
   EXPECT_THAT(reasm.FlushMessages(),
               ElementsAre(SctpMessageIs(kStreamID, kPPID, kShortPayload)));
 }

 TEST_F(ReassemblyQueueTest, TwoInterleavedChunks) {
   ReassemblyQueue reasm("log: ", TSN(10), kBufferSize,
                         /*use_message_interleaving=*/true);
   reasm.Add(TSN(10), Data(StreamID(1), SSN(0), MID(0), FSN(0), kPPID,
                           {1, 2, 3, 4}, Data::IsBeginning(true),
                           Data::IsEnd(false), IsUnordered(true)));
   reasm.Add(TSN(11), Data(StreamID(2), SSN(0), MID(0), FSN(0), kPPID,
                           {9, 10, 11, 12}, Data::IsBeginning(true),
                           Data::IsEnd(false), IsUnordered(true)));
   EXPECT_EQ(reasm.queued_bytes(), 8u);
   reasm.Add(TSN(12), Data(StreamID(1), SSN(0), MID(0), FSN(1), kPPID,
                           {5, 6, 7, 8}, Data::IsBeginning(false),
                           Data::IsEnd(true), IsUnordered(true)));
   EXPECT_EQ(reasm.queued_bytes(), 4u);
   reasm.Add(TSN(13), Data(StreamID(2), SSN(0), MID(0), FSN(1), kPPID,
                           {13, 14, 15, 16}, Data::IsBeginning(false),
                           Data::IsEnd(true), IsUnordered(true)));
   EXPECT_EQ(reasm.queued_bytes(), 0u);
   EXPECT_TRUE(reasm.HasMessages());
   EXPECT_THAT(reasm.FlushMessages(),
               ElementsAre(SctpMessageIs(StreamID(1), kPPID, kMediumPayload1),
                           SctpMessageIs(StreamID(2), kPPID, kMediumPayload2)));
 }

 TEST_F(ReassemblyQueueTest, UnorderedInterleavedMessagesAllPermutations) {
   std::vector<int> indexes = {0, 1, 2, 3, 4, 5};
   TSN tsns[] = {TSN(10), TSN(11), TSN(12), TSN(13), TSN(14), TSN(15)};
   StreamID stream_ids[] = {StreamID(1), StreamID(2), StreamID(1),
                            StreamID(1), StreamID(2), StreamID(2)};
   FSN fsns[] = {FSN(0), FSN(0), FSN(1), FSN(2), FSN(1), FSN(2)};
   rtc::ArrayView<const uint8_t> payload(kSixBytePayload);
   do {
     ReassemblyQueue reasm("log: ", TSN(10), kBufferSize,
                           /*use_message_interleaving=*/true);
     for (int i : indexes) {
       auto span = payload.subview(*fsns[i] * 2, 2);
       Data::IsBeginning is_beginning(fsns[i] == FSN(0));
       Data::IsEnd is_end(fsns[i] == FSN(2));
       reasm.Add(tsns[i], Data(stream_ids[i], SSN(0), MID(0), fsns[i], kPPID,
                               std::vector<uint8_t>(span.begin(), span.end()),
                               is_beginning, is_end, IsUnordered(true)));
     }
     EXPECT_TRUE(reasm.HasMessages());
     EXPECT_THAT(reasm.FlushMessages(),
                 UnorderedElementsAre(
                     SctpMessageIs(StreamID(1), kPPID, kSixBytePayload),
                     SctpMessageIs(StreamID(2), kPPID, kSixBytePayload)));
     EXPECT_EQ(reasm.queued_bytes(), 0u);
   } while (std::next_permutation(std::begin(indexes), std::end(indexes)));
 }

 TEST_F(ReassemblyQueueTest, IForwardTSNRemoveALotOrdered) {
   ReassemblyQueue reasm("log: ", TSN(10), kBufferSize,
                         /*use_message_interleaving=*/true);
   reasm.Add(TSN(10), gen_.Ordered({1}, "B"));
   gen_.Ordered({2}, "");
   reasm.Add(TSN(12), gen_.Ordered({3}, ""));
   reasm.Add(TSN(13), gen_.Ordered({4}, "E"));
   reasm.Add(TSN(15), gen_.Ordered({5}, "B"));
   reasm.Add(TSN(16), gen_.Ordered({6}, ""));
   reasm.Add(TSN(17), gen_.Ordered({7}, ""));
   reasm.Add(TSN(18), gen_.Ordered({8}, "E"));

   ASSERT_FALSE(reasm.HasMessages());
   EXPECT_EQ(reasm.queued_bytes(), 7u);

   reasm.Handle(
       IForwardTsnChunk(TSN(13), {IForwardTsnChunk::SkippedStream(
                                     IsUnordered(false), kStreamID, MID(0))}));
   EXPECT_EQ(reasm.queued_bytes(), 0u);

   // The lost chunk comes, but too late.
   ASSERT_TRUE(reasm.HasMessages());
   EXPECT_THAT(reasm.FlushMessages(),
               ElementsAre(SctpMessageIs(kStreamID, kPPID, kMessage2Payload)));
 }

 }  // namespace
 }  // namespace dcsctp
	/*
	* Copyright (c) 2021 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 "net/dcsctp/rx/reassembly_queue.h"

	#include <stddef.h>

	#include <algorithm>
	#include <array>
	#include <cstdint>
	#include <iterator>
	#include <vector>

	#include "api/array_view.h"
	#include "net/dcsctp/common/handover_testing.h"
	#include "net/dcsctp/packet/chunk/forward_tsn_chunk.h"
	#include "net/dcsctp/packet/chunk/forward_tsn_common.h"
	#include "net/dcsctp/packet/chunk/iforward_tsn_chunk.h"
	#include "net/dcsctp/packet/data.h"
	#include "net/dcsctp/public/dcsctp_message.h"
	#include "net/dcsctp/public/types.h"
	#include "net/dcsctp/testing/data_generator.h"
	#include "rtc_base/gunit.h"
	#include "test/gmock.h"

	namespace dcsctp {
	namespace {
	using ::testing::ElementsAre;
	using ::testing::SizeIs;
	using ::testing::UnorderedElementsAre;

	// The default maximum size of the Reassembly Queue.
	static constexpr size_t kBufferSize = 10000;

	static constexpr StreamID kStreamID(1);
	static constexpr SSN kSSN(0);
	static constexpr MID kMID(0);
	static constexpr FSN kFSN(0);
	static constexpr PPID kPPID(53);

	static constexpr std::array<uint8_t, 4> kShortPayload = {1, 2, 3, 4};
	static constexpr std::array<uint8_t, 4> kMessage2Payload = {5, 6, 7, 8};
	static constexpr std::array<uint8_t, 6> kSixBytePayload = {1, 2, 3, 4, 5, 6};
	static constexpr std::array<uint8_t, 8> kMediumPayload1 = {1, 2, 3, 4,
	5, 6, 7, 8};
	static constexpr std::array<uint8_t, 8> kMediumPayload2 = {9, 10, 11, 12,
	13, 14, 15, 16};
	static constexpr std::array<uint8_t, 16> kLongPayload = {
	1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16};

	MATCHER_P3(SctpMessageIs, stream_id, ppid, expected_payload, "") {
	if (arg.stream_id() != stream_id) {
	result_listener << "the stream_id is " << arg.stream_id();
	return false;
	}

	if (arg.ppid() != ppid) {
	result_listener << "the ppid is " << arg.ppid();
	return false;
	}

	if (std::vector<uint8_t>(arg.payload().begin(), arg.payload().end()) !=
	std::vector<uint8_t>(expected_payload.begin(), expected_payload.end())) {
	*result_listener << "the payload is wrong";
	return false;
	}
	return true;
	}

	class ReassemblyQueueTest : public testing::Test {
	protected:
	ReassemblyQueueTest() {}
	DataGenerator gen_;
	};

	TEST_F(ReassemblyQueueTest, EmptyQueue) {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
	EXPECT_FALSE(reasm.HasMessages());
	EXPECT_EQ(reasm.queued_bytes(), 0u);
	}

	TEST_F(ReassemblyQueueTest, SingleUnorderedChunkMessage) {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
	reasm.Add(TSN(10), gen_.Unordered({1, 2, 3, 4}, "BE"));
	EXPECT_TRUE(reasm.HasMessages());
	EXPECT_THAT(reasm.FlushMessages(),
	ElementsAre(SctpMessageIs(kStreamID, kPPID, kShortPayload)));
	EXPECT_EQ(reasm.queued_bytes(), 0u);
	}

	TEST_F(ReassemblyQueueTest, LargeUnorderedChunkAllPermutations) {
	std::vector<uint32_t> tsns = {10, 11, 12, 13};
	rtc::ArrayView<const uint8_t> payload(kLongPayload);
	do {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);

	for (size_t i = 0; i < tsns.size(); i++) {
	auto span = payload.subview((tsns[i] - 10) * 4, 4);
	Data::IsBeginning is_beginning(tsns[i] == 10);
	Data::IsEnd is_end(tsns[i] == 13);

	reasm.Add(TSN(tsns[i]),
	Data(kStreamID, kSSN, kMID, kFSN, kPPID,
	std::vector<uint8_t>(span.begin(), span.end()),
	is_beginning, is_end, IsUnordered(false)));
	if (i < 3) {
	EXPECT_FALSE(reasm.HasMessages());
	} else {
	EXPECT_TRUE(reasm.HasMessages());
	EXPECT_THAT(reasm.FlushMessages(),
	ElementsAre(SctpMessageIs(kStreamID, kPPID, kLongPayload)));
	EXPECT_EQ(reasm.queued_bytes(), 0u);
	}
	}
	} while (std::next_permutation(std::begin(tsns), std::end(tsns)));
	}

	TEST_F(ReassemblyQueueTest, SingleOrderedChunkMessage) {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
	reasm.Add(TSN(10), gen_.Ordered({1, 2, 3, 4}, "BE"));
	EXPECT_EQ(reasm.queued_bytes(), 0u);
	EXPECT_TRUE(reasm.HasMessages());
	EXPECT_THAT(reasm.FlushMessages(),
	ElementsAre(SctpMessageIs(kStreamID, kPPID, kShortPayload)));
	}

	TEST_F(ReassemblyQueueTest, ManySmallOrderedMessages) {
	std::vector<uint32_t> tsns = {10, 11, 12, 13};
	rtc::ArrayView<const uint8_t> payload(kLongPayload);
	do {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
	for (size_t i = 0; i < tsns.size(); i++) {
	auto span = payload.subview((tsns[i] - 10) * 4, 4);
	Data::IsBeginning is_beginning(true);
	Data::IsEnd is_end(true);

	SSN ssn(static_cast<uint16_t>(tsns[i] - 10));
	reasm.Add(TSN(tsns[i]),
	Data(kStreamID, ssn, kMID, kFSN, kPPID,
	std::vector<uint8_t>(span.begin(), span.end()),
	is_beginning, is_end, IsUnordered(false)));
	}
	EXPECT_THAT(
	reasm.FlushMessages(),
	ElementsAre(SctpMessageIs(kStreamID, kPPID, payload.subview(0, 4)),
	SctpMessageIs(kStreamID, kPPID, payload.subview(4, 4)),
	SctpMessageIs(kStreamID, kPPID, payload.subview(8, 4)),
	SctpMessageIs(kStreamID, kPPID, payload.subview(12, 4))));
	EXPECT_EQ(reasm.queued_bytes(), 0u);
	} while (std::next_permutation(std::begin(tsns), std::end(tsns)));
	}

	TEST_F(ReassemblyQueueTest, RetransmissionInLargeOrdered) {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
	reasm.Add(TSN(10), gen_.Ordered({1}, "B"));
	reasm.Add(TSN(12), gen_.Ordered({3}));
	reasm.Add(TSN(13), gen_.Ordered({4}));
	reasm.Add(TSN(14), gen_.Ordered({5}));
	reasm.Add(TSN(15), gen_.Ordered({6}));
	reasm.Add(TSN(16), gen_.Ordered({7}));
	reasm.Add(TSN(17), gen_.Ordered({8}));
	EXPECT_EQ(reasm.queued_bytes(), 7u);

	// lost and retransmitted
	reasm.Add(TSN(11), gen_.Ordered({2}));
	reasm.Add(TSN(18), gen_.Ordered({9}));
	reasm.Add(TSN(19), gen_.Ordered({10}));
	EXPECT_EQ(reasm.queued_bytes(), 10u);
	EXPECT_FALSE(reasm.HasMessages());

	reasm.Add(TSN(20), gen_.Ordered({11, 12, 13, 14, 15, 16}, "E"));
	EXPECT_TRUE(reasm.HasMessages());
	EXPECT_THAT(reasm.FlushMessages(),
	ElementsAre(SctpMessageIs(kStreamID, kPPID, kLongPayload)));
	EXPECT_EQ(reasm.queued_bytes(), 0u);
	}

	TEST_F(ReassemblyQueueTest, ForwardTSNRemoveUnordered) {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
	reasm.Add(TSN(10), gen_.Unordered({1}, "B"));
	reasm.Add(TSN(12), gen_.Unordered({3}));
	reasm.Add(TSN(13), gen_.Unordered({4}, "E"));

	reasm.Add(TSN(14), gen_.Unordered({5}, "B"));
	reasm.Add(TSN(15), gen_.Unordered({6}));
	reasm.Add(TSN(17), gen_.Unordered({8}, "E"));
	EXPECT_EQ(reasm.queued_bytes(), 6u);

	EXPECT_FALSE(reasm.HasMessages());

	reasm.Handle(ForwardTsnChunk(TSN(13), {}));
	EXPECT_EQ(reasm.queued_bytes(), 3u);

	// The lost chunk comes, but too late.
	reasm.Add(TSN(11), gen_.Unordered({2}));
	EXPECT_FALSE(reasm.HasMessages());
	EXPECT_EQ(reasm.queued_bytes(), 3u);

	// The second lost chunk comes, message is assembled.
	reasm.Add(TSN(16), gen_.Unordered({7}));
	EXPECT_TRUE(reasm.HasMessages());
	EXPECT_EQ(reasm.queued_bytes(), 0u);
	}

	TEST_F(ReassemblyQueueTest, ForwardTSNRemoveOrdered) {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
	reasm.Add(TSN(10), gen_.Ordered({1}, "B"));
	reasm.Add(TSN(12), gen_.Ordered({3}));
	reasm.Add(TSN(13), gen_.Ordered({4}, "E"));

	reasm.Add(TSN(14), gen_.Ordered({5}, "B"));
	reasm.Add(TSN(15), gen_.Ordered({6}));
	reasm.Add(TSN(16), gen_.Ordered({7}));
	reasm.Add(TSN(17), gen_.Ordered({8}, "E"));
	EXPECT_EQ(reasm.queued_bytes(), 7u);

	EXPECT_FALSE(reasm.HasMessages());

	reasm.Handle(ForwardTsnChunk(
	TSN(13), {ForwardTsnChunk::SkippedStream(kStreamID, kSSN)}));
	EXPECT_EQ(reasm.queued_bytes(), 0u);

	// The lost chunk comes, but too late.
	EXPECT_TRUE(reasm.HasMessages());
	EXPECT_THAT(reasm.FlushMessages(),
	ElementsAre(SctpMessageIs(kStreamID, kPPID, kMessage2Payload)));
	}

	TEST_F(ReassemblyQueueTest, ForwardTSNRemoveALotOrdered) {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
	reasm.Add(TSN(10), gen_.Ordered({1}, "B"));
	reasm.Add(TSN(12), gen_.Ordered({3}));
	reasm.Add(TSN(13), gen_.Ordered({4}, "E"));

	reasm.Add(TSN(15), gen_.Ordered({5}, "B"));
	reasm.Add(TSN(16), gen_.Ordered({6}));
	reasm.Add(TSN(17), gen_.Ordered({7}));
	reasm.Add(TSN(18), gen_.Ordered({8}, "E"));
	EXPECT_EQ(reasm.queued_bytes(), 7u);

	EXPECT_FALSE(reasm.HasMessages());

	reasm.Handle(ForwardTsnChunk(
	TSN(13), {ForwardTsnChunk::SkippedStream(kStreamID, kSSN)}));
	EXPECT_EQ(reasm.queued_bytes(), 0u);

	// The lost chunk comes, but too late.
	EXPECT_TRUE(reasm.HasMessages());
	EXPECT_THAT(reasm.FlushMessages(),
	ElementsAre(SctpMessageIs(kStreamID, kPPID, kMessage2Payload)));
	}

	TEST_F(ReassemblyQueueTest, ShouldntDeliverMessagesBeforeInitialTsn) {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
	reasm.Add(TSN(5), gen_.Unordered({1, 2, 3, 4}, "BE"));
	EXPECT_EQ(reasm.queued_bytes(), 0u);
	EXPECT_FALSE(reasm.HasMessages());
	}

	TEST_F(ReassemblyQueueTest, ShouldntRedeliverUnorderedMessages) {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
	reasm.Add(TSN(10), gen_.Unordered({1, 2, 3, 4}, "BE"));
	EXPECT_EQ(reasm.queued_bytes(), 0u);
	EXPECT_TRUE(reasm.HasMessages());
	EXPECT_THAT(reasm.FlushMessages(),
	ElementsAre(SctpMessageIs(kStreamID, kPPID, kShortPayload)));
	reasm.Add(TSN(10), gen_.Unordered({1, 2, 3, 4}, "BE"));
	EXPECT_EQ(reasm.queued_bytes(), 0u);
	EXPECT_FALSE(reasm.HasMessages());
	}

	TEST_F(ReassemblyQueueTest, ShouldntRedeliverUnorderedMessagesReallyUnordered) {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
	reasm.Add(TSN(10), gen_.Unordered({1, 2, 3, 4}, "B"));
	EXPECT_EQ(reasm.queued_bytes(), 4u);

	EXPECT_FALSE(reasm.HasMessages());

	reasm.Add(TSN(12), gen_.Unordered({1, 2, 3, 4}, "BE"));
	EXPECT_EQ(reasm.queued_bytes(), 4u);
	EXPECT_TRUE(reasm.HasMessages());

	EXPECT_THAT(reasm.FlushMessages(),
	ElementsAre(SctpMessageIs(kStreamID, kPPID, kShortPayload)));
	reasm.Add(TSN(12), gen_.Unordered({1, 2, 3, 4}, "BE"));
	EXPECT_EQ(reasm.queued_bytes(), 4u);
	EXPECT_FALSE(reasm.HasMessages());
	}

	TEST_F(ReassemblyQueueTest, ShouldntDeliverBeforeForwardedTsn) {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
	reasm.Handle(ForwardTsnChunk(TSN(12), {}));

	reasm.Add(TSN(12), gen_.Unordered({1, 2, 3, 4}, "BE"));
	EXPECT_EQ(reasm.queued_bytes(), 0u);
	EXPECT_FALSE(reasm.HasMessages());
	}

	TEST_F(ReassemblyQueueTest, NotReadyForHandoverWhenDeliveredTsnsHaveGap) {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
	reasm.Add(TSN(10), gen_.Unordered({1, 2, 3, 4}, "B"));
	EXPECT_FALSE(reasm.HasMessages());

	reasm.Add(TSN(12), gen_.Unordered({1, 2, 3, 4}, "BE"));
	EXPECT_TRUE(reasm.HasMessages());
	EXPECT_EQ(
	reasm.GetHandoverReadiness(),
	HandoverReadinessStatus()
	.Add(HandoverUnreadinessReason::kReassemblyQueueDeliveredTSNsGap)
	.Add(
	HandoverUnreadinessReason::kUnorderedStreamHasUnassembledChunks));

	EXPECT_THAT(reasm.FlushMessages(),
	ElementsAre(SctpMessageIs(kStreamID, kPPID, kShortPayload)));
	EXPECT_EQ(
	reasm.GetHandoverReadiness(),
	HandoverReadinessStatus()
	.Add(HandoverUnreadinessReason::kReassemblyQueueDeliveredTSNsGap)
	.Add(
	HandoverUnreadinessReason::kUnorderedStreamHasUnassembledChunks));

	reasm.Handle(ForwardTsnChunk(TSN(13), {}));
	EXPECT_EQ(reasm.GetHandoverReadiness(), HandoverReadinessStatus());
	}

	TEST_F(ReassemblyQueueTest, NotReadyForHandoverWhenResetStreamIsDeferred) {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
	DataGeneratorOptions opts;
	opts.message_id = MID(0);
	reasm.Add(TSN(10), gen_.Ordered({1, 2, 3, 4}, "BE", opts));
	opts.message_id = MID(1);
	reasm.Add(TSN(11), gen_.Ordered({1, 2, 3, 4}, "BE", opts));
	EXPECT_THAT(reasm.FlushMessages(), SizeIs(2));

	reasm.ResetStreams(
	OutgoingSSNResetRequestParameter(
	ReconfigRequestSN(10), ReconfigRequestSN(3), TSN(13), {StreamID(1)}),
	TSN(11));
	EXPECT_EQ(reasm.GetHandoverReadiness(),
	HandoverReadinessStatus().Add(
	HandoverUnreadinessReason::kStreamResetDeferred));

	opts.message_id = MID(3);
	opts.ppid = PPID(3);
	reasm.Add(TSN(13), gen_.Ordered({1, 2, 3, 4}, "BE", opts));
	reasm.MaybeResetStreamsDeferred(TSN(11));

	opts.message_id = MID(2);
	opts.ppid = PPID(2);
	reasm.Add(TSN(13), gen_.Ordered({1, 2, 3, 4}, "BE", opts));
	reasm.MaybeResetStreamsDeferred(TSN(15));
	EXPECT_EQ(reasm.GetHandoverReadiness(),
	HandoverReadinessStatus().Add(
	HandoverUnreadinessReason::kReassemblyQueueDeliveredTSNsGap));

	EXPECT_THAT(reasm.FlushMessages(), SizeIs(2));
	EXPECT_EQ(reasm.GetHandoverReadiness(),
	HandoverReadinessStatus().Add(
	HandoverUnreadinessReason::kReassemblyQueueDeliveredTSNsGap));

	reasm.Handle(ForwardTsnChunk(TSN(15), {}));
	EXPECT_EQ(reasm.GetHandoverReadiness(), HandoverReadinessStatus());
	}

	TEST_F(ReassemblyQueueTest, HandoverInInitialState) {
	ReassemblyQueue reasm1("log: ", TSN(10), kBufferSize);

	EXPECT_EQ(reasm1.GetHandoverReadiness(), HandoverReadinessStatus());
	DcSctpSocketHandoverState state;
	reasm1.AddHandoverState(state);
	g_handover_state_transformer_for_test(&state);
	ReassemblyQueue reasm2("log: ", TSN(100), kBufferSize,
	/use_message_interleaving=/false);
	reasm2.RestoreFromState(state);

	reasm2.Add(TSN(10), gen_.Ordered({1, 2, 3, 4}, "BE"));
	EXPECT_THAT(reasm2.FlushMessages(), SizeIs(1));
	}

	TEST_F(ReassemblyQueueTest, HandoverAfterHavingAssembedOneMessage) {
	ReassemblyQueue reasm1("log: ", TSN(10), kBufferSize);
	reasm1.Add(TSN(10), gen_.Ordered({1, 2, 3, 4}, "BE"));
	EXPECT_THAT(reasm1.FlushMessages(), SizeIs(1));

	EXPECT_EQ(reasm1.GetHandoverReadiness(), HandoverReadinessStatus());
	DcSctpSocketHandoverState state;
	reasm1.AddHandoverState(state);
	g_handover_state_transformer_for_test(&state);
	ReassemblyQueue reasm2("log: ", TSN(100), kBufferSize,
	/use_message_interleaving=/false);
	reasm2.RestoreFromState(state);

	reasm2.Add(TSN(11), gen_.Ordered({1, 2, 3, 4}, "BE"));
	EXPECT_THAT(reasm2.FlushMessages(), SizeIs(1));
	}

	TEST_F(ReassemblyQueueTest, HandleInconsistentForwardTSN) {
	// Found when fuzzing.
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize);
	// Add TSN=43, SSN=7. Can't be reassembled as previous SSNs aren't known.
	reasm.Add(TSN(43), Data(kStreamID, SSN(7), MID(0), FSN(0), kPPID,
	std::vector<uint8_t>(10), Data::IsBeginning(true),
	Data::IsEnd(true), IsUnordered(false)));

	// Invalid, as TSN=44 have to have SSN>=7, but peer says 6.
	reasm.Handle(ForwardTsnChunk(
	TSN(44), {ForwardTsnChunk::SkippedStream(kStreamID, SSN(6))}));

	// Don't assemble SSN=7, as that TSN is skipped.
	EXPECT_FALSE(reasm.HasMessages());
	}

	TEST_F(ReassemblyQueueTest, SingleUnorderedChunkMessageInRfc8260) {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize,
	/use_message_interleaving=/true);
	reasm.Add(TSN(10), Data(StreamID(1), SSN(0), MID(0), FSN(0), kPPID,
	{1, 2, 3, 4}, Data::IsBeginning(true),
	Data::IsEnd(true), IsUnordered(true)));
	EXPECT_EQ(reasm.queued_bytes(), 0u);
	EXPECT_TRUE(reasm.HasMessages());
	EXPECT_THAT(reasm.FlushMessages(),
	ElementsAre(SctpMessageIs(kStreamID, kPPID, kShortPayload)));
	}

	TEST_F(ReassemblyQueueTest, TwoInterleavedChunks) {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize,
	/use_message_interleaving=/true);
	reasm.Add(TSN(10), Data(StreamID(1), SSN(0), MID(0), FSN(0), kPPID,
	{1, 2, 3, 4}, Data::IsBeginning(true),
	Data::IsEnd(false), IsUnordered(true)));
	reasm.Add(TSN(11), Data(StreamID(2), SSN(0), MID(0), FSN(0), kPPID,
	{9, 10, 11, 12}, Data::IsBeginning(true),
	Data::IsEnd(false), IsUnordered(true)));
	EXPECT_EQ(reasm.queued_bytes(), 8u);
	reasm.Add(TSN(12), Data(StreamID(1), SSN(0), MID(0), FSN(1), kPPID,
	{5, 6, 7, 8}, Data::IsBeginning(false),
	Data::IsEnd(true), IsUnordered(true)));
	EXPECT_EQ(reasm.queued_bytes(), 4u);
	reasm.Add(TSN(13), Data(StreamID(2), SSN(0), MID(0), FSN(1), kPPID,
	{13, 14, 15, 16}, Data::IsBeginning(false),
	Data::IsEnd(true), IsUnordered(true)));
	EXPECT_EQ(reasm.queued_bytes(), 0u);
	EXPECT_TRUE(reasm.HasMessages());
	EXPECT_THAT(reasm.FlushMessages(),
	ElementsAre(SctpMessageIs(StreamID(1), kPPID, kMediumPayload1),
	SctpMessageIs(StreamID(2), kPPID, kMediumPayload2)));
	}

	TEST_F(ReassemblyQueueTest, UnorderedInterleavedMessagesAllPermutations) {
	std::vector<int> indexes = {0, 1, 2, 3, 4, 5};
	TSN tsns[] = {TSN(10), TSN(11), TSN(12), TSN(13), TSN(14), TSN(15)};
	StreamID stream_ids[] = {StreamID(1), StreamID(2), StreamID(1),
	StreamID(1), StreamID(2), StreamID(2)};
	FSN fsns[] = {FSN(0), FSN(0), FSN(1), FSN(2), FSN(1), FSN(2)};
	rtc::ArrayView<const uint8_t> payload(kSixBytePayload);
	do {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize,
	/use_message_interleaving=/true);
	for (int i : indexes) {
	auto span = payload.subview(fsns[i] 2, 2);
	Data::IsBeginning is_beginning(fsns[i] == FSN(0));
	Data::IsEnd is_end(fsns[i] == FSN(2));
	reasm.Add(tsns[i], Data(stream_ids[i], SSN(0), MID(0), fsns[i], kPPID,
	std::vector<uint8_t>(span.begin(), span.end()),
	is_beginning, is_end, IsUnordered(true)));
	}
	EXPECT_TRUE(reasm.HasMessages());
	EXPECT_THAT(reasm.FlushMessages(),
	UnorderedElementsAre(
	SctpMessageIs(StreamID(1), kPPID, kSixBytePayload),
	SctpMessageIs(StreamID(2), kPPID, kSixBytePayload)));
	EXPECT_EQ(reasm.queued_bytes(), 0u);
	} while (std::next_permutation(std::begin(indexes), std::end(indexes)));
	}

	TEST_F(ReassemblyQueueTest, IForwardTSNRemoveALotOrdered) {
	ReassemblyQueue reasm("log: ", TSN(10), kBufferSize,
	/use_message_interleaving=/true);
	reasm.Add(TSN(10), gen_.Ordered({1}, "B"));
	gen_.Ordered({2}, "");
	reasm.Add(TSN(12), gen_.Ordered({3}, ""));
	reasm.Add(TSN(13), gen_.Ordered({4}, "E"));
	reasm.Add(TSN(15), gen_.Ordered({5}, "B"));
	reasm.Add(TSN(16), gen_.Ordered({6}, ""));
	reasm.Add(TSN(17), gen_.Ordered({7}, ""));
	reasm.Add(TSN(18), gen_.Ordered({8}, "E"));

	ASSERT_FALSE(reasm.HasMessages());
	EXPECT_EQ(reasm.queued_bytes(), 7u);

	reasm.Handle(
	IForwardTsnChunk(TSN(13), {IForwardTsnChunk::SkippedStream(
	IsUnordered(false), kStreamID, MID(0))}));
	EXPECT_EQ(reasm.queued_bytes(), 0u);

	// The lost chunk comes, but too late.
	ASSERT_TRUE(reasm.HasMessages());
	EXPECT_THAT(reasm.FlushMessages(),
	ElementsAre(SctpMessageIs(kStreamID, kPPID, kMessage2Payload)));
	}

	} // namespace
	} // namespace dcsctp