Send and parse SCTP max-message-size in SDP
This also changes the default when no max-message-size is set
to the protocol defined value of 64K, and prevents messages
from being sent when they are too large to send.
Bug: webrtc:10358
Change-Id: Iacc1dd774d1554d9f27315378fbea6351300b5cc
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/135948
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Steve Anton <steveanton@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27945}
diff --git a/media/sctp/sctp_transport.cc b/media/sctp/sctp_transport.cc
index 8bcec41..b99a55b 100644
--- a/media/sctp/sctp_transport.cc
+++ b/media/sctp/sctp_transport.cc
@@ -46,9 +46,6 @@
// take off 80 bytes for DTLS/TURN/TCP/IP overhead.
static constexpr size_t kSctpMtu = 1200;
-// The size of the SCTP association send buffer. 256kB, the usrsctp default.
-static constexpr int kSendBufferSize = 256 * 1024;
-
// Set the initial value of the static SCTP Data Engines reference count.
int g_usrsctp_usage_count = 0;
rtc::GlobalLockPod g_usrsctp_lock_;
@@ -185,7 +182,7 @@
// This is harmless, but we should find out when the library default
// changes.
int send_size = usrsctp_sysctl_get_sctp_sendspace();
- if (send_size != kSendBufferSize) {
+ if (send_size != kSctpSendBufferSize) {
RTC_LOG(LS_ERROR) << "Got different send size than expected: "
<< send_size;
}
@@ -327,7 +324,7 @@
// callback. Larger messages (originating from other implementations) will
// still be delivered in chunks.
if (!(flags & MSG_EOR) &&
- (transport->partial_message_.size() < kSendBufferSize)) {
+ (transport->partial_message_.size() < kSctpSendBufferSize)) {
return 1;
}
@@ -410,7 +407,9 @@
}
}
-bool SctpTransport::Start(int local_sctp_port, int remote_sctp_port) {
+bool SctpTransport::Start(int local_sctp_port,
+ int remote_sctp_port,
+ int max_message_size) {
RTC_DCHECK_RUN_ON(network_thread_);
if (local_sctp_port == -1) {
local_sctp_port = kSctpDefaultPort;
@@ -418,6 +417,20 @@
if (remote_sctp_port == -1) {
remote_sctp_port = kSctpDefaultPort;
}
+ if (max_message_size > kSctpSendBufferSize) {
+ RTC_LOG(LS_ERROR) << "Max message size of " << max_message_size
+ << " is larger than send bufffer size "
+ << kSctpSendBufferSize;
+ return false;
+ }
+ if (max_message_size < 1) {
+ RTC_LOG(LS_ERROR) << "Max message size of " << max_message_size
+ << " is too small";
+ return false;
+ }
+ // We allow changing max_message_size with a second Start() call,
+ // but not changing the port numbers.
+ max_message_size_ = max_message_size;
if (started_) {
if (local_sctp_port != local_port_ || remote_sctp_port != remote_port_) {
RTC_LOG(LS_ERROR)
@@ -537,6 +550,11 @@
}
}
+ if (payload.size() > static_cast<size_t>(max_message_size_)) {
+ RTC_LOG(LS_ERROR) << "Attempting to send message of size " << payload.size()
+ << " which is larger than limit " << max_message_size_;
+ return false;
+ }
// We don't fragment.
send_res = usrsctp_sendv(
sock_, payload.data(), static_cast<size_t>(payload.size()), NULL, 0, &spa,
@@ -657,9 +675,9 @@
UsrSctpWrapper::IncrementUsrSctpUsageCount();
- // If kSendBufferSize isn't reflective of reality, we log an error, but we
- // still have to do something reasonable here. Look up what the buffer's
- // real size is and set our threshold to something reasonable.
+ // If kSctpSendBufferSize isn't reflective of reality, we log an error, but we
+ // still have to do something reasonable here. Look up what the buffer's real
+ // size is and set our threshold to something reasonable.
static const int kSendThreshold = usrsctp_sysctl_get_sctp_sendspace() / 2;
sock_ = usrsctp_socket(
diff --git a/media/sctp/sctp_transport.h b/media/sctp/sctp_transport.h
index dccecd8..554407b 100644
--- a/media/sctp/sctp_transport.h
+++ b/media/sctp/sctp_transport.h
@@ -72,13 +72,14 @@
// SctpTransportInternal overrides (see sctptransportinternal.h for comments).
void SetDtlsTransport(rtc::PacketTransportInternal* transport) override;
- bool Start(int local_port, int remote_port) override;
+ bool Start(int local_port, int remote_port, int max_message_size) override;
bool OpenStream(int sid) override;
bool ResetStream(int sid) override;
bool SendData(const SendDataParams& params,
const rtc::CopyOnWriteBuffer& payload,
SendDataResult* result = nullptr) override;
bool ReadyToSendData() override;
+ int max_message_size() const override { return max_message_size_; }
void set_debug_name_for_testing(const char* debug_name) override {
debug_name_ = debug_name;
}
@@ -151,6 +152,7 @@
bool was_ever_writable_ = false;
int local_port_ = kSctpDefaultPort;
int remote_port_ = kSctpDefaultPort;
+ int max_message_size_ = kSctpSendBufferSize;
struct socket* sock_ = nullptr; // The socket created by usrsctp_socket(...).
// Has Start been called? Don't create SCTP socket until it has.
diff --git a/media/sctp/sctp_transport_internal.h b/media/sctp/sctp_transport_internal.h
index 12f1782..c08c414 100644
--- a/media/sctp/sctp_transport_internal.h
+++ b/media/sctp/sctp_transport_internal.h
@@ -28,6 +28,10 @@
namespace cricket {
+// Constants that are important to API users
+// The size of the SCTP association send buffer. 256kB, the usrsctp default.
+constexpr int kSctpSendBufferSize = 256 * 1024;
+
// The number of outgoing streams that we'll negotiate. Since stream IDs (SIDs)
// are 0-based, the highest usable SID is 1023.
//
@@ -67,13 +71,16 @@
// listener and connector must be using the same port. They are not related
// to the ports at the IP level. If set to -1, we default to
// kSctpDefaultPort.
+ // |max_message_size_| sets the max message size on the connection.
+ // It must be smaller than or equal to kSctpSendBufferSize.
+ // It can be changed by a secons Start() call.
//
- // TODO(deadbeef): Add remote max message size as parameter to Start, once we
- // start supporting it.
// TODO(deadbeef): Support calling Start with different local/remote ports
// and create a new association? Not clear if this is something we need to
// support though. See: https://github.com/w3c/webrtc-pc/issues/979
- virtual bool Start(int local_sctp_port, int remote_sctp_port) = 0;
+ virtual bool Start(int local_sctp_port,
+ int remote_sctp_port,
+ int max_message_size) = 0;
// NOTE: Initially there was a "Stop" method here, but it was never used, so
// it was removed.
@@ -105,6 +112,8 @@
// ICE channels may be unwritable while ReadyToSendData is true, because data
// can still be queued in usrsctp.
virtual bool ReadyToSendData() = 0;
+ // Returns the current max message size, set with Start().
+ virtual int max_message_size() const = 0;
sigslot::signal0<> SignalReadyToSendData;
// ReceiveDataParams includes SID, seq num, timestamp, etc. CopyOnWriteBuffer
diff --git a/media/sctp/sctp_transport_unittest.cc b/media/sctp/sctp_transport_unittest.cc
index 86cb416..d7ccd58 100644
--- a/media/sctp/sctp_transport_unittest.cc
+++ b/media/sctp/sctp_transport_unittest.cc
@@ -151,8 +151,8 @@
<< "Connect the transports -----------------------------";
// Both transports need to have started (with matching ports) for an
// association to be formed.
- transport1_->Start(port1, port2);
- transport2_->Start(port2, port1);
+ transport1_->Start(port1, port2, kSctpSendBufferSize);
+ transport2_->Start(port2, port1, kSctpSendBufferSize);
}
bool AddStream(int sid) {
@@ -251,8 +251,8 @@
transport2->OpenStream(1);
// Tell them both to start (though transport1_ is connected to black_hole).
- transport1->Start(kTransport1Port, kTransport2Port);
- transport2->Start(kTransport2Port, kTransport1Port);
+ transport1->Start(kTransport1Port, kTransport2Port, kSctpSendBufferSize);
+ transport2->Start(kTransport2Port, kTransport1Port, kSctpSendBufferSize);
// Switch transport1_ to the normal fake_dtls1_ transport.
transport1->SetDtlsTransport(&fake_dtls1);
@@ -276,7 +276,8 @@
// Calling Start twice shouldn't do anything bad, if with the same parameters.
TEST_F(SctpTransportTest, DuplicateStartCallsIgnored) {
SetupConnectedTransportsWithTwoStreams();
- EXPECT_TRUE(transport1()->Start(kTransport1Port, kTransport2Port));
+ EXPECT_TRUE(transport1()->Start(kTransport1Port, kTransport2Port,
+ kSctpSendBufferSize));
// Make sure we can still send/recv data.
SendDataResult result;
@@ -289,8 +290,8 @@
// Calling Start a second time with a different port should fail.
TEST_F(SctpTransportTest, CallingStartWithDifferentPortFails) {
SetupConnectedTransportsWithTwoStreams();
- EXPECT_FALSE(transport1()->Start(kTransport1Port, 1234));
- EXPECT_FALSE(transport1()->Start(1234, kTransport2Port));
+ EXPECT_FALSE(transport1()->Start(kTransport1Port, 1234, kSctpSendBufferSize));
+ EXPECT_FALSE(transport1()->Start(1234, kTransport2Port, kSctpSendBufferSize));
}
// A value of -1 for the local/remote port should be treated as the default
@@ -311,8 +312,8 @@
// Tell them both to start, giving one transport the default port and the
// other transport -1.
- transport1->Start(kSctpDefaultPort, kSctpDefaultPort);
- transport2->Start(-1, -1);
+ transport1->Start(kSctpDefaultPort, kSctpDefaultPort, kSctpSendBufferSize);
+ transport2->Start(-1, -1, kSctpSendBufferSize);
// Connect the two fake DTLS transports.
bool asymmetric = false;
@@ -351,7 +352,7 @@
std::unique_ptr<SctpTransport> transport(CreateTransport(&fake_dtls, &recv));
SctpTransportObserver observer(transport.get());
- transport->Start(kSctpDefaultPort, kSctpDefaultPort);
+ transport->Start(kSctpDefaultPort, kSctpDefaultPort, kSctpSendBufferSize);
fake_dtls.SetWritable(true);
EXPECT_TRUE_WAIT(observer.ReadyToSend(), kDefaultTimeout);
}
@@ -564,4 +565,31 @@
EXPECT_EQ_WAIT(2, transport2_observer.StreamCloseCount(1), kDefaultTimeout);
}
+TEST_F(SctpTransportTest, RejectsTooLargeMessageSize) {
+ FakeDtlsTransport fake_dtls("fake dtls", 0);
+ SctpFakeDataReceiver recv;
+ std::unique_ptr<SctpTransport> transport(CreateTransport(&fake_dtls, &recv));
+
+ EXPECT_FALSE(transport->Start(kSctpDefaultPort, kSctpDefaultPort,
+ kSctpSendBufferSize + 1));
+}
+
+TEST_F(SctpTransportTest, RejectsTooSmallMessageSize) {
+ FakeDtlsTransport fake_dtls("fake dtls", 0);
+ SctpFakeDataReceiver recv;
+ std::unique_ptr<SctpTransport> transport(CreateTransport(&fake_dtls, &recv));
+
+ EXPECT_FALSE(transport->Start(kSctpDefaultPort, kSctpDefaultPort, 0));
+}
+
+TEST_F(SctpTransportTest, RejectsSendTooLargeMessages) {
+ SetupConnectedTransportsWithTwoStreams();
+ // Use "Start" to reduce the max message size
+ transport1()->Start(kTransport1Port, kTransport2Port, 10);
+ EXPECT_EQ(10, transport1()->max_message_size());
+ const char eleven_characters[] = "12345678901";
+ SendDataResult result;
+ EXPECT_FALSE(SendData(transport1(), 1, eleven_characters, &result));
+}
+
} // namespace cricket
diff --git a/pc/media_session.cc b/pc/media_session.cc
index 69ebb84..0924e6d 100644
--- a/pc/media_session.cc
+++ b/pc/media_session.cc
@@ -25,6 +25,7 @@
#include "api/crypto_params.h"
#include "media/base/h264_profile_level_id.h"
#include "media/base/media_constants.h"
+#include "media/sctp/sctp_transport_internal.h"
#include "p2p/base/p2p_constants.h"
#include "pc/channel_manager.h"
#include "pc/media_protocol_names.h"
@@ -2238,6 +2239,8 @@
data->set_protocol(secure_transport ? kMediaProtocolUdpDtlsSctp
: kMediaProtocolSctp);
data->set_use_sctpmap(session_options.use_obsolete_sctp_sdp);
+ data->set_max_message_size(kSctpSendBufferSize);
+
if (!CreateContentOffer(media_description_options, session_options,
sdes_policy, GetCryptos(current_content),
crypto_suites, RtpHeaderExtensions(), ssrc_generator_,
@@ -2579,6 +2582,10 @@
offer_content->media_description()->as_sctp();
// Respond with the offerer's proto, whatever it is.
data_answer->as_sctp()->set_protocol(offer_data_description->protocol());
+ // Respond with our max message size or the remote max messsage size,
+ // whichever is smaller.
+ data_answer->as_sctp()->set_max_message_size(std::min(
+ offer_data_description->max_message_size(), kSctpSendBufferSize));
if (!CreateMediaContentAnswer(
offer_data_description, media_description_options, session_options,
sdes_policy, GetCryptos(current_content), RtpHeaderExtensions(),
diff --git a/pc/peer_connection.cc b/pc/peer_connection.cc
index fcd1a2a..e1cc6ef 100644
--- a/pc/peer_connection.cc
+++ b/pc/peer_connection.cc
@@ -556,18 +556,6 @@
return true;
}
-// Get the SCTP port out of a SessionDescription.
-// Return -1 if not found.
-int GetSctpPort(const SessionDescription* session_description) {
- const cricket::SctpDataContentDescription* data_desc =
- GetFirstSctpDataContentDescription(session_description);
- RTC_DCHECK(data_desc);
- if (!data_desc) {
- return -1;
- }
- return data_desc->port();
-}
-
// Returns true if |new_desc| requests an ICE restart (i.e., new ufrag/pwd).
bool CheckForRemoteIceRestart(const SessionDescriptionInterface* old_desc,
const SessionDescriptionInterface* new_desc,
@@ -5663,17 +5651,24 @@
// Need complete offer/answer with an SCTP m= section before starting SCTP,
// according to https://tools.ietf.org/html/draft-ietf-mmusic-sctp-sdp-19
- if (sctp_transport_ && local_description() && remote_description() &&
- cricket::GetFirstDataContent(local_description()->description()) &&
- cricket::GetFirstDataContent(remote_description()->description())) {
- bool success = network_thread()->Invoke<bool>(
- RTC_FROM_HERE,
- rtc::Bind(&PeerConnection::PushdownSctpParameters_n, this, source,
- GetSctpPort(local_description()->description()),
- GetSctpPort(remote_description()->description())));
- if (!success) {
- LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR,
- "Failed to push down SCTP parameters.");
+ if (sctp_transport_ && local_description() && remote_description()) {
+ auto local_sctp_description = cricket::GetFirstSctpDataContentDescription(
+ local_description()->description());
+ auto remote_sctp_description = cricket::GetFirstSctpDataContentDescription(
+ remote_description()->description());
+ if (local_sctp_description && remote_sctp_description) {
+ int max_message_size =
+ std::min(local_sctp_description->max_message_size(),
+ remote_sctp_description->max_message_size());
+ bool success = network_thread()->Invoke<bool>(
+ RTC_FROM_HERE,
+ rtc::Bind(&PeerConnection::PushdownSctpParameters_n, this, source,
+ local_sctp_description->port(),
+ remote_sctp_description->port(), max_message_size));
+ if (!success) {
+ LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR,
+ "Failed to push down SCTP parameters.");
+ }
}
}
@@ -5682,11 +5677,13 @@
bool PeerConnection::PushdownSctpParameters_n(cricket::ContentSource source,
int local_sctp_port,
- int remote_sctp_port) {
+ int remote_sctp_port,
+ int max_message_size) {
RTC_DCHECK_RUN_ON(network_thread());
// Apply the SCTP port (which is hidden inside a DataCodec structure...)
// When we support "max-message-size", that would also be pushed down here.
- return cricket_sctp_transport()->Start(local_sctp_port, remote_sctp_port);
+ return cricket_sctp_transport()->Start(local_sctp_port, remote_sctp_port,
+ max_message_size);
}
RTCError PeerConnection::PushdownTransportDescription(
diff --git a/pc/peer_connection.h b/pc/peer_connection.h
index be46980..e83ef1e 100644
--- a/pc/peer_connection.h
+++ b/pc/peer_connection.h
@@ -879,7 +879,8 @@
RTC_RUN_ON(signaling_thread());
bool PushdownSctpParameters_n(cricket::ContentSource source,
int local_sctp_port,
- int remote_sctp_port);
+ int remote_sctp_port,
+ int max_message_size);
RTCError PushdownTransportDescription(cricket::ContentSource source,
SdpType type);
diff --git a/pc/sctp_transport.cc b/pc/sctp_transport.cc
index 1db149f..d23d619 100644
--- a/pc/sctp_transport.cc
+++ b/pc/sctp_transport.cc
@@ -105,8 +105,14 @@
must_send_update = (state != info_.state());
// TODO(https://bugs.webrtc.org/10358): Update max message size and
// max channels from internal SCTP transport when available.
- info_ = SctpTransportInformation(
- state, dtls_transport_, info_.MaxMessageSize(), info_.MaxChannels());
+ if (internal_sctp_transport_) {
+ info_ = SctpTransportInformation(
+ state, dtls_transport_, internal_sctp_transport_->max_message_size(),
+ info_.MaxChannels());
+ } else {
+ info_ = SctpTransportInformation(
+ state, dtls_transport_, info_.MaxMessageSize(), info_.MaxChannels());
+ }
if (observer_ && must_send_update) {
info_copy = info_;
}
diff --git a/pc/sctp_transport_unittest.cc b/pc/sctp_transport_unittest.cc
index 3771b2c..3438b17 100644
--- a/pc/sctp_transport_unittest.cc
+++ b/pc/sctp_transport_unittest.cc
@@ -32,7 +32,9 @@
class FakeCricketSctpTransport : public cricket::SctpTransportInternal {
public:
void SetDtlsTransport(rtc::PacketTransportInternal* transport) override {}
- bool Start(int local_port, int remote_port) override { return true; }
+ bool Start(int local_port, int remote_port, int max_message_size) override {
+ return true;
+ }
bool OpenStream(int sid) override { return true; }
bool ResetStream(int sid) override { return true; }
bool SendData(const cricket::SendDataParams& params,
@@ -42,6 +44,7 @@
}
bool ReadyToSendData() override { return true; }
void set_debug_name_for_testing(const char* debug_name) override {}
+ int max_message_size() const override { return 0; }
// Methods exposed for testing
void SendSignalReadyToSendData() { SignalReadyToSendData(); }
diff --git a/pc/session_description.h b/pc/session_description.h
index 27b781f..fe08e3a 100644
--- a/pc/session_description.h
+++ b/pc/session_description.h
@@ -498,7 +498,8 @@
bool use_sctpmap_ = true; // Note: "true" is no longer conformant.
// Defaults should be constants imported from SCTP. Quick hack.
int port_ = 5000;
- int max_message_size_ = 256 * 1024;
+ // draft-ietf-mmusic-sdp-sctp-23: Max message size default is 64K
+ int max_message_size_ = 64 * 1024;
std::unique_ptr<DataContentDescription> shim_;
};
diff --git a/pc/test/fake_sctp_transport.h b/pc/test/fake_sctp_transport.h
index b2c5c1a..b3eeee0 100644
--- a/pc/test/fake_sctp_transport.h
+++ b/pc/test/fake_sctp_transport.h
@@ -21,9 +21,10 @@
class FakeSctpTransport : public cricket::SctpTransportInternal {
public:
void SetDtlsTransport(rtc::PacketTransportInternal* transport) override {}
- bool Start(int local_port, int remote_port) override {
+ bool Start(int local_port, int remote_port, int max_message_size) override {
local_port_.emplace(local_port);
remote_port_.emplace(remote_port);
+ max_message_size_ = max_message_size;
return true;
}
bool OpenStream(int sid) override { return true; }
@@ -36,12 +37,14 @@
bool ReadyToSendData() override { return true; }
void set_debug_name_for_testing(const char* debug_name) override {}
+ int max_message_size() const { return max_message_size_; }
int local_port() const { return *local_port_; }
int remote_port() const { return *remote_port_; }
private:
absl::optional<int> local_port_;
absl::optional<int> remote_port_;
+ int max_message_size_;
};
class FakeSctpTransportFactory : public cricket::SctpTransportInternalFactory {
diff --git a/pc/webrtc_sdp.cc b/pc/webrtc_sdp.cc
index c6968b1..0c09fa2 100644
--- a/pc/webrtc_sdp.cc
+++ b/pc/webrtc_sdp.cc
@@ -172,6 +172,7 @@
// a=sctp-port, a=max-message-size
static const char kAttributeSctpPort[] = "sctp-port";
static const char kAttributeMaxMessageSize[] = "max-message-size";
+static const int kDefaultSctpMaxMessageSize = 65536;
// draft-ietf-mmusic-sdp-simulcast-13
// a=simulcast
static const char kAttributeSimulcast[] = "simulcast";
@@ -272,9 +273,6 @@
const std::vector<Candidate>& candidates,
int msid_signaling,
std::string* message);
-static void BuildSctpContentAttributes(std::string* message,
- int sctp_port,
- bool use_sctpmap);
static void BuildRtpContentAttributes(const MediaContentDescription* media_desc,
const cricket::MediaType media_type,
int msid_signaling,
@@ -1323,6 +1321,33 @@
return true;
}
+static void BuildSctpContentAttributes(
+ std::string* message,
+ const cricket::SctpDataContentDescription* data_desc) {
+ rtc::StringBuilder os;
+ if (data_desc->use_sctpmap()) {
+ // draft-ietf-mmusic-sctp-sdp-04
+ // a=sctpmap:sctpmap-number protocol [streams]
+ rtc::StringBuilder os;
+ InitAttrLine(kAttributeSctpmap, &os);
+ os << kSdpDelimiterColon << data_desc->port() << kSdpDelimiterSpace
+ << kDefaultSctpmapProtocol << kSdpDelimiterSpace
+ << cricket::kMaxSctpStreams;
+ AddLine(os.str(), message);
+ } else {
+ // draft-ietf-mmusic-sctp-sdp-23
+ // a=sctp-port:<port>
+ InitAttrLine(kAttributeSctpPort, &os);
+ os << kSdpDelimiterColon << data_desc->port();
+ AddLine(os.str(), message);
+ if (data_desc->max_message_size() != kDefaultSctpMaxMessageSize) {
+ InitAttrLine(kAttributeMaxMessageSize, &os);
+ os << kSdpDelimiterColon << data_desc->max_message_size();
+ AddLine(os.str(), message);
+ }
+ }
+}
+
void BuildMediaDescription(const ContentInfo* content_info,
const TransportInfo* transport_info,
const cricket::MediaType media_type,
@@ -1518,34 +1543,12 @@
if (cricket::IsDtlsSctp(media_desc->protocol())) {
const cricket::SctpDataContentDescription* data_desc =
media_desc->as_sctp();
- bool use_sctpmap = data_desc->use_sctpmap();
- BuildSctpContentAttributes(message, data_desc->port(), use_sctpmap);
+ BuildSctpContentAttributes(message, data_desc);
} else if (cricket::IsRtpProtocol(media_desc->protocol())) {
BuildRtpContentAttributes(media_desc, media_type, msid_signaling, message);
}
}
-void BuildSctpContentAttributes(std::string* message,
- int sctp_port,
- bool use_sctpmap) {
- rtc::StringBuilder os;
- if (use_sctpmap) {
- // draft-ietf-mmusic-sctp-sdp-04
- // a=sctpmap:sctpmap-number protocol [streams]
- InitAttrLine(kAttributeSctpmap, &os);
- os << kSdpDelimiterColon << sctp_port << kSdpDelimiterSpace
- << kDefaultSctpmapProtocol << kSdpDelimiterSpace
- << cricket::kMaxSctpStreams;
- } else {
- // draft-ietf-mmusic-sctp-sdp-23
- // a=sctp-port:<port>
- InitAttrLine(kAttributeSctpPort, &os);
- os << kSdpDelimiterColon << sctp_port;
- // TODO(zstein): emit max-message-size here
- }
- AddLine(os.str(), message);
-}
-
void BuildRtpContentAttributes(const MediaContentDescription* media_desc,
const cricket::MediaType media_type,
int msid_signaling,
@@ -2706,6 +2709,9 @@
// m=application <port> UDP/DTLS/SCTP webrtc-datachannel
// use_sctpmap should be false.
auto data_desc = absl::make_unique<SctpDataContentDescription>();
+ // Default max message size is 64K
+ // according to draft-ietf-mmusic-sctp-sdp-26
+ data_desc->set_max_message_size(kDefaultSctpMaxMessageSize);
int p;
if (rtc::FromString(fields[3], &p)) {
data_desc->set_port(p);
diff --git a/pc/webrtc_sdp_unittest.cc b/pc/webrtc_sdp_unittest.cc
index 1d3e6a3..a3a8749 100644
--- a/pc/webrtc_sdp_unittest.cc
+++ b/pc/webrtc_sdp_unittest.cc
@@ -2891,6 +2891,34 @@
EXPECT_TRUE(CompareSessionDescription(jdesc, jdesc_output));
}
+TEST_F(WebRtcSdpTest, SerializeSdpWithSctpDataChannelWithMaxMessageSize) {
+ bool use_sctpmap = false;
+ AddSctpDataChannel(use_sctpmap);
+ JsepSessionDescription jdesc(kDummyType);
+ MutateJsepSctpMaxMessageSize(desc_, 12345, &jdesc);
+ std::string message = webrtc::SdpSerialize(jdesc);
+ EXPECT_NE(std::string::npos,
+ message.find("\r\na=max-message-size:12345\r\n"));
+ JsepSessionDescription jdesc_output(kDummyType);
+ EXPECT_TRUE(SdpDeserialize(message, &jdesc_output));
+ EXPECT_TRUE(CompareSessionDescription(jdesc, jdesc_output));
+}
+
+TEST_F(WebRtcSdpTest,
+ SerializeSdpWithSctpDataChannelWithDefaultMaxMessageSize) {
+ // https://tools.ietf.org/html/draft-ietf-mmusic-sctp-sdp-26#section-6
+ // The default max message size is 64K.
+ bool use_sctpmap = false;
+ AddSctpDataChannel(use_sctpmap);
+ JsepSessionDescription jdesc(kDummyType);
+ MutateJsepSctpMaxMessageSize(desc_, 65536, &jdesc);
+ std::string message = webrtc::SdpSerialize(jdesc);
+ EXPECT_EQ(std::string::npos, message.find("\r\na=max-message-size:"));
+ JsepSessionDescription jdesc_output(kDummyType);
+ EXPECT_TRUE(SdpDeserialize(message, &jdesc_output));
+ EXPECT_TRUE(CompareSessionDescription(jdesc, jdesc_output));
+}
+
// Test to check the behaviour if sctp-port is specified
// on the m= line and in a=sctp-port.
TEST_F(WebRtcSdpTest, DeserializeSdpWithMultiSctpPort) {
