127 lines
3.6 KiB
Go
127 lines
3.6 KiB
Go
// Copyright 2013, Cong Ding. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// Author: Cong Ding <dinggnu@gmail.com>
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package stun
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import (
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"errors"
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"net"
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"strconv"
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)
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// Client is a STUN client, which can be set STUN server address and is used
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// to discover NAT type.
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type Client struct {
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serverAddr string
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softwareName string
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conn net.PacketConn
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logger *Logger
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}
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// NewClient returns a client without network connection. The network
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// connection will be build when calling Discover function.
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func NewClient() *Client {
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c := new(Client)
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c.SetSoftwareName(DefaultSoftwareName)
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c.logger = NewLogger()
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return c
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}
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// NewClientWithConnection returns a client which uses the given connection.
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// Please note the connection should be acquired via net.Listen* method.
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func NewClientWithConnection(conn net.PacketConn) *Client {
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c := new(Client)
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c.conn = conn
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c.SetSoftwareName(DefaultSoftwareName)
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c.logger = NewLogger()
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return c
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}
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// SetVerbose sets the client to be in the verbose mode, which prints
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// information in the discover process.
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func (c *Client) SetVerbose(v bool) {
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c.logger.SetDebug(v)
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}
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// SetVVerbose sets the client to be in the double verbose mode, which prints
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// information and packet in the discover process.
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func (c *Client) SetVVerbose(v bool) {
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c.logger.SetInfo(v)
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}
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// SetServerHost allows user to set the STUN hostname and port.
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func (c *Client) SetServerHost(host string, port int) {
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c.serverAddr = net.JoinHostPort(host, strconv.Itoa(port))
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}
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// SetServerAddr allows user to set the transport layer STUN server address.
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func (c *Client) SetServerAddr(address string) {
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c.serverAddr = address
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}
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// SetSoftwareName allows user to set the name of the software, which is used
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// for logging purpose (NOT used in the current implementation).
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func (c *Client) SetSoftwareName(name string) {
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c.softwareName = name
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}
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// Discover contacts the STUN server and gets the response of NAT type, host
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// for UDP punching.
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func (c *Client) Discover() (NATType, *Host, error) {
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if c.serverAddr == "" {
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c.SetServerAddr(DefaultServerAddr)
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}
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serverUDPAddr, err := net.ResolveUDPAddr("udp", c.serverAddr)
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if err != nil {
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return NATError, nil, err
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}
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// Use the connection passed to the client if it is not nil, otherwise
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// create a connection and close it at the end.
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conn := c.conn
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if conn == nil {
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conn, err = net.ListenUDP("udp", nil)
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if err != nil {
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return NATError, nil, err
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}
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defer conn.Close()
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}
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return c.discover(conn, serverUDPAddr)
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}
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// Keepalive sends and receives a bind request, which ensures the mapping stays open
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// Only applicable when client was created with a connection.
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func (c *Client) Keepalive() (*Host, error) {
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if c.conn == nil {
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return nil, errors.New("no connection available")
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}
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if c.serverAddr == "" {
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c.SetServerAddr(DefaultServerAddr)
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}
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serverUDPAddr, err := net.ResolveUDPAddr("udp", c.serverAddr)
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if err != nil {
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return nil, err
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}
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resp, err := c.test1(c.conn, serverUDPAddr)
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if err != nil {
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return nil, err
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}
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if resp == nil || resp.packet == nil {
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return nil, errors.New("failed to contact")
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}
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return resp.mappedAddr, nil
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}
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