Add (Experimental) Meyka Building Blocks to request Transport

[xiaokangwang]

This is an experimental functionality that does not currently have configuration file or protocol forward compatibility assurance. Please expect to change your config file as this functionality get refined.

This merge request added a packetconn based connection assembler that attempt to reassemble an connection from with an UDP based transport protocol, over an unreliable connection abstraction of a request based connection state(let's say HTTP Requests).

Be aware that this protocol is designed to work with or without streaming downloads, and when streaming downloads is absent, it may not be obvious that something has gone wrong.

Here is an tested to work configuration files:

Client:

{
  "log": {
    "error": {
      "level": "Debug",
      "type": "Console"
    },
    "access": {
      "type": "None"
    }
  },
  "outbounds": [
    {
      "protocol": "vmess",
      "settings": {
        "address": "****",
        "port": 443,
        "uuid": "****"
      },
      "streamSettings": {
        "transport": "request",
        "transportSettings": {
          "assembler": {
            "@type": "types.v2fly.org/v2ray.core.transport.internet.request.assembler.packetconn.ClientConfig",
            "underlying_transport_name": "kcp",
            "underlying_transport_setting": {
              "@type": "v2ray.core.transport.internet.kcp.Config",
              "mtu": {
                "value": 1450
              },
              "tti": {
                "value": 15
              },
              "uplink_capacity": {
                "value": 40
              },
              "downlink_capacity": {
                "value": 2000
              },
              "congestion": false,
              "write_buffer": {
                "size": 671088640
              },
              "read_buffer": {
                "size": 671088640
              }
            },
            "max_write_delay": 80,
            "max_request_size": 96000,
            "polling_interval_initial": 200
          },
          "roundtripper": {
            "@type": "types.v2fly.org/v2ray.core.transport.internet.request.roundtripper.httprt.ClientConfig",
            "http": {
              "path": "****"
            },
            "allow_http": false,
            "h2_pool_size": 8
          }
        },
        "security": "tls",
        "securitySettings": {
          "nextProtocol": [
            "h2",
            "http/1.1"
          ]
        }
      }
    }
  ],
  "inbounds": [
    {
      "protocol": "socks",
      "settings": {
        "udpEnabled": true,
        "address": "127.0.0.1",
        "packetEncoding": "Packet"
      },
      "port": ****,
      "listen": "127.0.0.1"
    },
    {
      "protocol": "http",
      "settings": {
      },
      "port": ****,
      "listen": "127.0.0.1"
    }
  ]
}

nginx:

location /**** {
        proxy_pass http://****;
        proxy_http_version 1.1;

        ###Set WebSocket headers ####
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $connection_upgrade;

        ### Set Proxy headers ####
        proxy_set_header        Accept-Encoding   "";
        proxy_set_header        Host            $host;
        proxy_set_header        X-Real-IP       $remote_addr;
        proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;

        proxy_set_header Client-Cert $ssl_client_escaped_cert;

        ### Most PHP, Python, Rails, Java App can use this header ###
        proxy_set_header        X-Forwarded-Proto $scheme;
        add_header              Front-End-Https   on;

        proxy_redirect     off;
        proxy_buffering off;
}

server:

{
  "log": {
    "error": {
      "level": "Debug",
      "type": "Console"
    },
    "access": {
      "type": "None"
    }
  },
  "outbounds": [
    {
      "protocol": "freedom"
    }
  ],
  "inbounds": [
    {
      "listen": "****",
      "port": ****,
      "protocol": "vmess",
      "settings": {
        "users": [
          "****"
        ]
      },
      "streamSettings": {
        "transport": "request",
        "transportSettings": {
          "assembler": {
            "@type": "types.v2fly.org/v2ray.core.transport.internet.request.assembler.packetconn.ServerConfig",
            "underlying_transport_name": "kcp",
            "underlying_transport_setting": {
              "@type": "v2ray.core.transport.internet.kcp.Config",
              "mtu": {
                "value": 1450
              },
              "tti": {
                "value": 15
              },
              "uplink_capacity": {
                "value": 40
              },
              "downlink_capacity": {
                "value": 1000
              },
              "congestion": false,
              "write_buffer": {
                "size": 671088640
              },
              "read_buffer": {
                "size": 671088640
              }
            },
            "max_write_size": 10485760,
            "max_write_duration_ms": 5000,
            "max_simultaneous_write_connection": 128,
            "packet_writing_buffer": 65536
          },
          "roundtripper": {
            "@type": "types.v2fly.org/v2ray.core.transport.internet.request.roundtripper.httprt.ServerConfig",
            "http": {
              "path": "http://****/"
            }
          }
        },
        "security": "none",
        "securitySettings": {
        }
      }
    }
  ]
}