How to send HTTP3 request between server and client

[Purushoth24051999]

I have written HTTP3 listener using a sample provided in the MSQUIC library, and my server listens in the 5000 port.

I want to receive HTTPS requests in GET, POST, and OPTIONS methods and send responses for those.

I have triggered a request from CURL. Since curl rejects self-signed certificates I have requested an insecure connection using the below command,

curl -v --http3 --insecure https://192.168.1.114:5000 

For a single request from a client I have received 3 QUIC_STREAM_EVENT_RECEIVE triggers and the data received in the stream is not in readable format. I have mentioned my code in ServerStreamCallback()

case QUIC_STREAM_EVENT_RECEIVE:
{
	std::cout << "[strm][" << stream << "] Data received:\nBuffer_count: " << streamEvent->RECEIVE.BufferCount << std::endl
		<< "total_buffer_length: " << streamEvent->RECEIVE.TotalBufferLength << std::endl;

	std::string receivedData;
	for (int i = 0; i < streamEvent->RECEIVE.BufferCount; i++)
	{
		auto& length = streamEvent->RECEIVE.Buffers[i].Length;
		std::string data(length, '\0');
		memcpy(&data[0], streamEvent->RECEIVE.Buffers[i].Buffer, length);
		receivedData += data;
	}
	std::cout << "Received data: " << receivedData << std::endl;

	std::string response = "HTTP/3 200 OK\r\nContent-Length: 2\r\n\r\nOK";
	ServerSend(stream, response);
	break;
}

OUTPUT in HTTP3 listener:

OUTPUT in CURL client:

NOTE:

If I send a data from client written using MSQUIC the above server code works well.

MSQUIC CLIENT CODE:

void Http3Client::ClientSend(HQUIC connection)
{
	try
	{
		QUIC_STATUS status;
		HQUIC stream = NULL;
		uint8_t* sendBufferRaw;
		QUIC_BUFFER* sendBuffer;

		if (QUIC_SUCCEEDED(status = MsQuicHelper::msQuic->StreamOpen(connection, QUIC_STREAM_OPEN_FLAG_NONE, ClientStreamCallback, NULL, &stream)))
		{
			printf("[strm][%p] Starting...\n", stream);

			if (QUIC_SUCCEEDED(status = MsQuicHelper::msQuic->StreamStart(stream, QUIC_STREAM_START_FLAG_NONE)))
			{
				std::string http3Request = "GET /test?viewId=10137&userId=101 HTTP/3\r\nHost: " + targetIp + "\r\n\r\n";
				MsQuicHelper::sendBufferLength = http3Request.size();
				sendBufferRaw = (uint8_t*)malloc(sizeof(QUIC_BUFFER) + MsQuicHelper::sendBufferLength);
				if (sendBufferRaw != NULL)
				{
					sendBuffer = (QUIC_BUFFER*)sendBufferRaw;
					sendBuffer->Buffer = sendBufferRaw + sizeof(QUIC_BUFFER);
					sendBuffer->Length = MsQuicHelper::sendBufferLength;
					memcpy(sendBuffer->Buffer, http3Request.data(), sendBuffer->Length);

					std::cout << "[strm][" << stream << "]\n" << sendBuffer->Buffer << "\nSending data..." << std::endl;

					if (QUIC_FAILED(status = MsQuicHelper::msQuic->StreamSend(stream, sendBuffer, 1, QUIC_SEND_FLAG_FIN, sendBuffer)))
					{
						std::cout << "StreamSend failed. Status: " << std::hex << status << std::endl;
						free(sendBufferRaw);
						goto Http3ClientError;
					}
				}
				else
				{
					std::cout << "SendBuffer allocation failed!" << std::endl;
					status = QUIC_STATUS_OUT_OF_MEMORY;
					goto Http3ClientError;
				}
			}
			else
			{
				std::cout << "StreamStart failed. Status: " << std::hex << status << std::endl;
				MsQuicHelper::msQuic->StreamClose(stream);
				goto Http3ClientError;
			}

		}
		else
		{
			std::cout << "StreamOpen failed. Status: " << std::hex << status << std::endl;
			goto Http3ClientError;
		}

	Http3ClientError:

		if (QUIC_FAILED(status))
			MsQuicHelper::msQuic->ConnectionShutdown(connection, QUIC_CONNECTION_SHUTDOWN_FLAG_NONE, 0);
	}
	catch(...)
       {
               std::cout << "Exception in ClientSend()\n";
       } 
}

OUTPUT OF HTTP3 LISTENER:

OUTPUT OF MSQUIC CLIENT:

[nibanks]

Feel free to take a look at how I do this in msh3: https://github.com/nibanks/msh3/blob/main/lib/msh3.cpp

[Purushoth24051999]

Is the received request in my case is encoded, if so it is mandatory for me to use ls-quack to encode and decode it?

[anrossi]

HTTP/3 (and HTTP/2) uses a binary format for the headers and messages in HTTP, while HTTP/1.1 used human-readable text.
So yes, you'll need to decode the received frames using some QPACK library, such as ls-qpack.

[Purushoth24051999]

I have tried MSH3 library and successfully implemented HTTP3 listener with your examples but the client example provided in MSH3 is not working and below snippet breaks by throwing "One or more invalid arguments error"

 status = MsH3ConnectionStart(connection, config, hostname, &serverAddr);
    if (MSH3_FAILED(status)) {
        printf("Failed to start connection, status=0x%x\n", status);
        MsH3ConnectionClose(connection);
        MsH3ConfigurationClose(config);
        MsH3ApiClose(api);
        return 1;
    }

@nibanks

[nibanks]

The sample might be out of date. Look at the test and tools for a working example.

[Purushoth24051999]

Yeah I got the sample and its working fine. But when I try to trigger request with ":path" which is more than 300 length ls-qpack encoding fails at client end. If the length of ":path" is less than that it works fine. Is there any limit for length of ":path"

std::string route = "/test_route?sample=100&sample1=100&sample2=100&sample3=100&sample4=100&sample5=100&sample6=100&sample7=100&sample8=100&sample9=100&sample10=100&sample11=100&sample12=100&sample13=100&sample14=100&sample15=100&sample16=100&sample17=100&sample18=100&sample19=100&sample20=100&sample21=100&sample22=100";

MSH3_HEADER headers[] = {
{ ":method", 7, "GET", 3 },
{ ":path", 5, route.c_str(), 299 },
{ ":scheme", 7, "https", 5 },
{ ":authority", 10, "127.0.0.1", 9 },
{ "user-agent", 10, "client", 6 },
{ "accept", 6, "*/*", 3 }
}

ERROR: lsqpack_enc_encode failed, 2

In the above snippet the route is just a sample one, Similar to the above route I use query parameter with lengthy values. If I trigger the same route using curl.exe without MSH3 client code it works fine for length routes.

@nibanks

[nibanks]

I didn't remember off hand, but I wouldn't be surprised if I used a static 256 byte buffer for the storage. You'd have to check. If so, I welcome a PR to improve this limitation.