SCTP: updating dcsctp

https://webrtc.googlesource.com/src/+/adb224b3e9e0df3dbd5c5a49a413cfe66e3ea7d4

Author: tbeloqui

subprojects/gst-plugins-bad/ext/sctp/dcsctp/absl/types/variant.h

@@ -15,32 +15,44 @@
 
 #include "absl/types/optional.h"
 #include "api/array_view.h"
+#include "rtc_base/strings/string_builder.h"
 
 namespace dcsctp {
 
 // https://www.ietf.org/archive/id/draft-tuexen-tsvwg-sctp-zero-checksum-00.html#section-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
-//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-//  |         Type = 0x8001         |          Length = 4           |
-//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//  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
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+// |   Type = 0x8001 (suggested)   |          Length = 8           |
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+// |           Error Detection Method Identifier (EDMID)           |
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 constexpr int ZeroChecksumAcceptableChunkParameter::kType;
 
 absl::optional<ZeroChecksumAcceptableChunkParameter>
 ZeroChecksumAcceptableChunkParameter::Parse(
     rtc::ArrayView<const uint8_t> data) {
-  if (!ParseTLV(data).has_value()) {
+  absl::optional<BoundedByteReader<kHeaderSize>> reader = ParseTLV(data);
+  if (!reader.has_value()) {
     return absl::nullopt;
   }
-  return ZeroChecksumAcceptableChunkParameter();
+
+  ZeroChecksumAlternateErrorDetectionMethod method(reader->Load32<4>());
+  if (method == ZeroChecksumAlternateErrorDetectionMethod::None()) {
+    return absl::nullopt;
+  }
+  return ZeroChecksumAcceptableChunkParameter(method);
 }
 
 void ZeroChecksumAcceptableChunkParameter::SerializeTo(
     std::vector<uint8_t>& out) const {
-  AllocateTLV(out);
+  BoundedByteWriter<kHeaderSize> writer = AllocateTLV(out);
+  writer.Store32<4>(*error_detection_method_);
 }
 
 std::string ZeroChecksumAcceptableChunkParameter::ToString() const {
-  return "Zero Checksum Acceptable";
+  rtc::StringBuilder sb;
+  sb << "Zero Checksum Acceptable (" << *error_detection_method_ << ")";
+  return sb.Release();
 }
 }  // namespace dcsctp

subprojects/gst-plugins-bad/ext/sctp/dcsctp/net/dcsctp/common/str_join.h

@@ -19,13 +19,14 @@
 #include "api/array_view.h"
 #include "net/dcsctp/packet/parameter/parameter.h"
 #include "net/dcsctp/packet/tlv_trait.h"
+#include "net/dcsctp/public/types.h"
 
 namespace dcsctp {
 
-// https://datatracker.ietf.org/doc/draft-tuexen-tsvwg-sctp-zero-checksum/
+// https://datatracker.ietf.org/doc/draft-ietf-tsvwg-sctp-zero-checksum/
 struct ZeroChecksumAcceptableChunkParameterConfig : ParameterConfig {
   static constexpr int kType = 0x8001;
-  static constexpr size_t kHeaderSize = 4;
+  static constexpr size_t kHeaderSize = 8;
   static constexpr size_t kVariableLengthAlignment = 0;
 };
 
@@ -36,13 +37,22 @@ class ZeroChecksumAcceptableChunkParameter
   static constexpr int kType =
       ZeroChecksumAcceptableChunkParameterConfig::kType;
 
-  ZeroChecksumAcceptableChunkParameter() {}
+  explicit ZeroChecksumAcceptableChunkParameter(
+      ZeroChecksumAlternateErrorDetectionMethod error_detection_method)
+      : error_detection_method_(error_detection_method) {}
 
   static absl::optional<ZeroChecksumAcceptableChunkParameter> Parse(
       rtc::ArrayView<const uint8_t> data);
 
   void SerializeTo(std::vector<uint8_t>& out) const override;
   std::string ToString() const override;
+
+  ZeroChecksumAlternateErrorDetectionMethod error_detection_method() const {
+    return error_detection_method_;
+  }
+
+ private:
+  ZeroChecksumAlternateErrorDetectionMethod error_detection_method_;
 };
 
 }  // namespace dcsctp

subprojects/gst-plugins-bad/ext/sctp/dcsctp/net/dcsctp/packet/parameter/zero_checksum_acceptable_chunk_parameter.cc

@@ -126,7 +126,9 @@ absl::optional<SctpPacket> SctpPacket::Parse(rtc::ArrayView<const uint8_t> data,
       std::vector<uint8_t>(data.begin(), data.end());
 
   if (options.disable_checksum_verification ||
-      (options.enable_zero_checksum && common_header.checksum == 0u)) {
+      (options.zero_checksum_alternate_error_detection_method !=
+           ZeroChecksumAlternateErrorDetectionMethod::None() &&
+       common_header.checksum == 0u)) {
     // https://www.ietf.org/archive/id/draft-tuexen-tsvwg-sctp-zero-checksum-01.html#section-4.3:
     // If an end point has sent the Zero Checksum Acceptable Chunk Parameter in
     // an INIT or INIT ACK chunk, it MUST accept SCTP packets using an incorrect

subprojects/gst-plugins-bad/ext/sctp/dcsctp/net/dcsctp/packet/parameter/zero_checksum_acceptable_chunk_parameter.h

@@ -85,10 +85,14 @@ struct DcSctpOptions {
   // buffer is fully utilized.
   size_t max_receiver_window_buffer_size = 5 * 1024 * 1024;
 
-  // Maximum send buffer size. It will not be possible to queue more data than
-  // this before sending it.
+  // Send queue total size limit. It will not be possible to queue more data if
+  // the queue size is larger than this number.
   size_t max_send_buffer_size = 2'000'000;
 
+  // Per stream send queue size limit. Similar to `max_send_buffer_size`, but
+  // limiting the size of individual streams.
+  size_t per_stream_send_queue_limit = 2'000'000;
+
   // A threshold that, when the amount of data in the send buffer goes below
   // this value, will trigger `DcSctpCallbacks::OnTotalBufferedAmountLow`.
   size_t total_buffered_amount_low_threshold = 1'800'000;
@@ -144,8 +148,11 @@ struct DcSctpOptions {
   // processing time of received packets and the clock granularity when setting
   // the delayed ack timer on the peer.
   //
-  // This is described for TCP in
+  // This is defined as "G" in the algorithm for TCP in
   // https://datatracker.ietf.org/doc/html/rfc6298#section-4.
+  //
+  // Note that this value will be further adjusted by scaling factors, so if you
+  // intend to change this, do it incrementally and measure the results.
   DurationMs min_rtt_variance = DurationMs(220);
 
   // The initial congestion window size, in number of MTUs.
@@ -196,14 +203,13 @@ struct DcSctpOptions {
   // Disables SCTP packet crc32 verification. For fuzzers only!
   bool disable_checksum_verification = false;
 
-  // Controls the acceptance of zero checksum, as defined in
-  // https://datatracker.ietf.org/doc/draft-tuexen-tsvwg-sctp-zero-checksum/
-  // This should only be enabled if the packet integrity can be ensured by lower
-  // layers, which DTLS will do in WebRTC, as defined by RFC8261.
-  //
-  // This will also enable sending packets without a checksum value (set to 0)
-  // once both peers have negotiated this feature.
-  bool enable_zero_checksum = false;
+  // Controls the "zero checksum option" feature, as defined in
+  // https://www.ietf.org/archive/id/draft-ietf-tsvwg-sctp-zero-checksum-06.html.
+  // To have this feature enabled, both peers must be configured to use the
+  // same (defined, not "none") alternate error detection method.
+  ZeroChecksumAlternateErrorDetectionMethod
+      zero_checksum_alternate_error_detection_method =
+          ZeroChecksumAlternateErrorDetectionMethod::None();
 };
 }  // namespace dcsctp
 

subprojects/gst-plugins-bad/ext/sctp/dcsctp/net/dcsctp/packet/sctp_packet.cc

@@ -13,6 +13,7 @@
 #include <cstdint>
 #include <memory>
 #include <utility>
+#include <vector>
 
 #include "absl/strings/string_view.h"
 #include "absl/types/optional.h"
@@ -577,6 +578,16 @@ class DcSctpSocketInterface {
   virtual SendStatus Send(DcSctpMessage message,
                           const SendOptions& send_options) = 0;
 
+  // Sends the messages `messages` using the provided send options.
+  // Sending a message is an asynchronous operation, and the `OnError` callback
+  // may be invoked to indicate any errors in sending the message.
+  //
+  // This has identical semantics to Send, except that it may coalesce many
+  // messages into a single SCTP packet if they would fit.
+  virtual std::vector<SendStatus> SendMany(
+      rtc::ArrayView<DcSctpMessage> messages,
+      const SendOptions& send_options) = 0;
+
   // Resetting streams is an asynchronous operation and the results will
   // be notified using `DcSctpSocketCallbacks::OnStreamsResetDone()` on success
   // and `DcSctpSocketCallbacks::OnStreamsResetFailed()` on failure. Note that

subprojects/gst-plugins-bad/ext/sctp/dcsctp/net/dcsctp/public/dcsctp_options.h

@@ -151,6 +151,27 @@ class LifecycleId : public webrtc::StrongAlias<class LifecycleIdTag, uint64_t> {
 
   static constexpr LifecycleId NotSet() { return LifecycleId(0); }
 };
+
+// To enable zero checksum feature, both peers must agree on which alternate
+// error detection method that is used. See
+// https://www.ietf.org/archive/id/draft-ietf-tsvwg-sctp-zero-checksum-06.html.
+class ZeroChecksumAlternateErrorDetectionMethod
+    : public webrtc::StrongAlias<
+          class ZeroChecksumAlternateErrorDetectionMethodTag,
+          uint32_t> {
+ public:
+  constexpr explicit ZeroChecksumAlternateErrorDetectionMethod(
+      const UnderlyingType& v)
+      : webrtc::StrongAlias<class ZeroChecksumAlternateErrorDetectionMethodTag,
+                            uint32_t>(v) {}
+
+  static constexpr ZeroChecksumAlternateErrorDetectionMethod None() {
+    return ZeroChecksumAlternateErrorDetectionMethod(0);
+  }
+  static constexpr ZeroChecksumAlternateErrorDetectionMethod LowerLayerDtls() {
+    return ZeroChecksumAlternateErrorDetectionMethod(1);
+  }
+};
 }  // namespace dcsctp
 
 #endif  // NET_DCSCTP_PUBLIC_TYPES_H_

subprojects/gst-plugins-bad/ext/sctp/dcsctp/net/dcsctp/public/dcsctp_socket.h

@@ -27,6 +27,7 @@
 #include "net/dcsctp/packet/data.h"
 #include "net/dcsctp/packet/parameter/outgoing_ssn_reset_request_parameter.h"
 #include "net/dcsctp/packet/parameter/reconfiguration_response_parameter.h"
+#include "net/dcsctp/public/dcsctp_handover_state.h"
 #include "net/dcsctp/public/dcsctp_message.h"
 #include "net/dcsctp/public/types.h"
 #include "net/dcsctp/rx/interleaved_reassembly_streams.h"
@@ -51,13 +52,11 @@ std::unique_ptr<ReassemblyStreams> CreateStreams(
 }  // namespace
 
 ReassemblyQueue::ReassemblyQueue(absl::string_view log_prefix,
-                                 TSN peer_initial_tsn,
                                  size_t max_size_bytes,
                                  bool use_message_interleaving)
     : log_prefix_(log_prefix),
       max_size_bytes_(max_size_bytes),
       watermark_bytes_(max_size_bytes * kHighWatermarkLimit),
-      last_completed_reset_req_seq_nbr_(ReconfigRequestSN(0)),
       streams_(CreateStreams(
           log_prefix_,
           [this](rtc::ArrayView<const UnwrappedTSN> tsns,
@@ -222,17 +221,10 @@ HandoverReadinessStatus ReassemblyQueue::GetHandoverReadiness() const {
 }
 
 void ReassemblyQueue::AddHandoverState(DcSctpSocketHandoverState& state) {
-  state.rx.last_completed_deferred_reset_req_sn =
-      last_completed_reset_req_seq_nbr_.value();
   streams_->AddHandoverState(state);
 }
 
 void ReassemblyQueue::RestoreFromState(const DcSctpSocketHandoverState& state) {
-  // Validate that the component is in pristine state.
-  RTC_DCHECK(last_completed_reset_req_seq_nbr_ == ReconfigRequestSN(0));
-
-  last_completed_reset_req_seq_nbr_ =
-      ReconfigRequestSN(state.rx.last_completed_deferred_reset_req_sn);
   streams_->RestoreFromState(state);
 }
 }  // namespace dcsctp

subprojects/gst-plugins-bad/ext/sctp/dcsctp/net/dcsctp/public/types.h

@@ -28,7 +28,6 @@
 #include "net/dcsctp/packet/data.h"
 #include "net/dcsctp/packet/parameter/outgoing_ssn_reset_request_parameter.h"
 #include "net/dcsctp/packet/parameter/reconfiguration_response_parameter.h"
-#include "net/dcsctp/public/dcsctp_handover_state.h"
 #include "net/dcsctp/public/dcsctp_message.h"
 #include "net/dcsctp/rx/reassembly_streams.h"
 #include "rtc_base/containers/flat_set.h"
@@ -72,7 +71,6 @@ class ReassemblyQueue {
   static constexpr float kHighWatermarkLimit = 0.9;
 
   ReassemblyQueue(absl::string_view log_prefix,
-                  TSN peer_initial_tsn,
                   size_t max_size_bytes,
                   bool use_message_interleaving = false);
 
@@ -155,10 +153,6 @@ class ReassemblyQueue {
   // If present, "deferred reset processing" mode is active.
   absl::optional<DeferredResetStreams> deferred_reset_streams_;
 
-  // Contains the last request sequence number of the
-  // OutgoingSSNResetRequestParameter that was performed.
-  ReconfigRequestSN last_completed_reset_req_seq_nbr_;
-
   // The number of "payload bytes" that are in this queue, in total.
   size_t queued_bytes_ = 0;