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3a45d32d4e
Reporting the duplicate TSNs is a SHOULD in the RFC, and using the duplicate TNSs is a MAY, and in reality I haven't seen an implementation use it yet. However, it's good for debugging and for stats generation. Bug: webrtc:12614 Change-Id: I1cc3f86961a8d289708cbf50d98dedfd25077955 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/219462 Reviewed-by: Florent Castelli <orphis@webrtc.org> Commit-Queue: Victor Boivie <boivie@webrtc.org> Cr-Commit-Position: refs/heads/master@{#34053}
87 lines
2.7 KiB
C++
87 lines
2.7 KiB
C++
/*
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* Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "net/dcsctp/packet/chunk_validators.h"
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#include <algorithm>
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#include <utility>
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#include <vector>
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#include "net/dcsctp/packet/chunk/sack_chunk.h"
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#include "rtc_base/logging.h"
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namespace dcsctp {
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SackChunk ChunkValidators::Clean(SackChunk&& sack) {
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if (Validate(sack)) {
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return std::move(sack);
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}
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RTC_DLOG(LS_WARNING) << "Received SACK is malformed; cleaning it";
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std::vector<SackChunk::GapAckBlock> gap_ack_blocks;
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gap_ack_blocks.reserve(sack.gap_ack_blocks().size());
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// First: Only keep blocks that are sane
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for (const SackChunk::GapAckBlock& gap_ack_block : sack.gap_ack_blocks()) {
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if (gap_ack_block.end > gap_ack_block.start) {
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gap_ack_blocks.emplace_back(gap_ack_block);
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}
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}
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// Not more than at most one remaining? Exit early.
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if (gap_ack_blocks.size() <= 1) {
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return SackChunk(sack.cumulative_tsn_ack(), sack.a_rwnd(),
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std::move(gap_ack_blocks), sack.duplicate_tsns());
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}
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// Sort the intervals by their start value, to aid in the merging below.
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absl::c_sort(gap_ack_blocks, [&](const SackChunk::GapAckBlock& a,
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const SackChunk::GapAckBlock& b) {
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return a.start < b.start;
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});
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// Merge overlapping ranges.
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std::vector<SackChunk::GapAckBlock> merged;
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merged.reserve(gap_ack_blocks.size());
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merged.push_back(gap_ack_blocks[0]);
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for (size_t i = 1; i < gap_ack_blocks.size(); ++i) {
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if (merged.back().end + 1 >= gap_ack_blocks[i].start) {
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merged.back().end = std::max(merged.back().end, gap_ack_blocks[i].end);
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} else {
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merged.push_back(gap_ack_blocks[i]);
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}
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}
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return SackChunk(sack.cumulative_tsn_ack(), sack.a_rwnd(), std::move(merged),
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sack.duplicate_tsns());
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}
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bool ChunkValidators::Validate(const SackChunk& sack) {
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if (sack.gap_ack_blocks().empty()) {
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return true;
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}
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// Ensure that gap-ack-blocks are sorted, has an "end" that is not before
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// "start" and are non-overlapping and non-adjacent.
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uint16_t prev_end = 0;
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for (const SackChunk::GapAckBlock& gap_ack_block : sack.gap_ack_blocks()) {
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if (gap_ack_block.end < gap_ack_block.start) {
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return false;
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}
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if (gap_ack_block.start <= (prev_end + 1)) {
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return false;
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}
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prev_end = gap_ack_block.end;
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}
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return true;
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}
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} // namespace dcsctp
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