本篇博客记录本次使用golang语言tcp方式进行telnet服务器访问
环境：
1、win7系统telnet服务器，使用地址：192.168.8.189
2、python使用telnetlib库对telnet服务器进行访问的客户端例程
3、服务端用户名：admin 密码：123456
本次功能实现过程：
第一步：抓包获取telnet交互流程分析
1、打开cmd。输入：telnet 192.168.8.189 访问 telnet服务器，依次输入用户名密码，登录成功后输入：exit 退出；
2、打开wireshark对上述流程进行抓包；
流查看抓包内容如下：
转储16进制查看：
内容分析结果：
1、回车换行内容为：0d 0a 也就是window本身的换行： ;
2、回显内容包含大量屏幕坐标信息，基本无法直接使用；
看到该内容后想起以前使用python进行telnet服务器访问时，回显内容无屏幕坐标信息，遂找出以前写的python程序对访问信息进行抓包查看：
第二步：用使用telnetlib库编写的python程序对服务器进行访问，对交互流程抓包
转储16进制：
查看内容发现回显内容无屏幕坐标信息，对比两次交互内容，决定使用golang对方式二进行模拟，注意图中红色框内信息；
golang程序例程：
第一步：创建连接
func telnet_Creat(host string,usr string,pass string) (conn net.Conn, err error) { telnetClientObj := new(TelnetClient) telnetClientObj.IP = host telnetClientObj.Port = "23" telnetClientObj.IsAuthentication = true telnetClientObj.UserName = usr telnetClientObj.Password = pass conn,err =telnetClientObj.Telnet(20) return conn,err }
func (this *TelnetClient) Telnet(timeout int) (conn net.Conn, err error) {
raddr := this.IP + ":" + this.Port
conn, err = net.DialTimeout("tcp", raddr, time.Duration(timeout)*time.Second)
if nil != err {
log.Print("pkg: model, func: Telnet, method: net.DialTimeout, errInfo:", err)
return
}
if false == this.telnetProtocolHandshake(conn) {
log.Print("pkg: model, func: Telnet, method: this.telnetProtocolHandshake, errInfo: telnet protocol handshake failed!!!")
return
}
return
}
第二步：模拟登录（telnetProtocolHandshake）
func (this *TelnetClient) telnetProtocolHandshake(conn net.Conn) bool { var buf [4096]byte log.Print("telnetProtocolHandshake") n, err := conn.Read(buf[0:]) if nil != err { log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Read, errInfo:", err) return false } log.Print("1====",string(buf[0:n])) log.Printf("%x",(buf[0:n])) buf[0] = 0xff buf[1] = 0xfc buf[2] = 0x25 buf[3] = 0xff buf[4] = 0xfe buf[5] = 0x01 n, err = conn.Write(buf[0:6]) if nil != err { log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Write, errInfo:", err) return false } n, err = conn.Read(buf[0:]) if nil != err { log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Read, errInfo:", err) return false } log.Print("2====",string(buf[0:n])) buf[0] = 0xff buf[1] = 0xfe buf[2] = 0x03 buf[3] = 0xff buf[4] = 0xfc buf[5] = 0x27 n, err = conn.Write(buf[0:6]) if nil != err { log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Write, errInfo:", err) return false } n, err = conn.Read(buf[0:]) if nil != err { log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Read, errInfo:", err) return false } log.Print("3====",string(buf[0:n])) n, err = conn.Write([]byte(this.UserName + " ")) if nil != err { log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Write, errInfo:", err) return false } time.Sleep(time.Millisecond * 500) n, err = conn.Read(buf[0:]) if nil != err { log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Read, errInfo:", err) return false } log.Print("4====",string(buf[0:n])) n, err = conn.Write([]byte(this.Password+ " ")) if nil != err { log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Write, errInfo:", err) return false } time.Sleep(time.Millisecond * 2000) n, err = conn.Read(buf[0:]) if nil != err { log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Read, errInfo:", err) return false } log.Print("5====",string(buf[0:n])) buf[0] = 0xff buf[1] = 0xfc buf[2] = 0x18 n, err = conn.Write(buf[0:3]) if nil != err { log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Write, errInfo:", err) return false } n, err = conn.Read(buf[0:]) if nil != err { log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Read, errInfo:", err) return false } log.Print("6====",string(buf[0:n])) return true }
完整程序：
package tool import ( "log" "net" "time" ) type TelnetClient struct { IP string Port string IsAuthentication bool UserName string Password string } func main() { conn,err:= telnet_Creat(host,usr,pass) if nil != err { return err } defer conn.Close() //后续对conn进行操作即可 }
func telnet_Creat(host string,usr string,pass string) (conn net.Conn, err error) {
telnetClientObj := new(TelnetClient)
telnetClientObj.IP = host
telnetClientObj.Port = "23"
telnetClientObj.IsAuthentication = true
telnetClientObj.UserName = usr
telnetClientObj.Password = pass
conn,err =telnetClientObj.Telnet(20)
return conn,err
}
func (this *TelnetClient) Telnet(timeout int) (conn net.Conn, err error) {
raddr := this.IP + ":" + this.Port
conn, err = net.DialTimeout("tcp", raddr, time.Duration(timeout)*time.Second)
if nil != err {
log.Print("pkg: model, func: Telnet, method: net.DialTimeout, errInfo:", err)
return
}
if false == this.telnetProtocolHandshake(conn) {
log.Print("pkg: model, func: Telnet, method: this.telnetProtocolHandshake, errInfo: telnet protocol handshake failed!!!")
return
}
return
}
func (this *TelnetClient) telnetProtocolHandshake(conn net.Conn) bool {
var buf [4096]byte
log.Print("telnetProtocolHandshake")
n, err := conn.Read(buf[0:])
if nil != err {
log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Read, errInfo:", err)
return false
}
log.Print("1====",string(buf[0:n]))
log.Printf("%x",(buf[0:n]))
buf[0] = 0xff
buf[1] = 0xfc
buf[2] = 0x25
buf[3] = 0xff
buf[4] = 0xfe
buf[5] = 0x01
n, err = conn.Write(buf[0:6])
if nil != err {
log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Write, errInfo:", err)
return false
}
n, err = conn.Read(buf[0:])
if nil != err {
log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Read, errInfo:", err)
return false
}
log.Print("2====",string(buf[0:n]))
buf[0] = 0xff
buf[1] = 0xfe
buf[2] = 0x03
buf[3] = 0xff
buf[4] = 0xfc
buf[5] = 0x27
n, err = conn.Write(buf[0:6])
if nil != err {
log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Write, errInfo:", err)
return false
}
n, err = conn.Read(buf[0:])
if nil != err {
log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Read, errInfo:", err)
return false
}
log.Print("3====",string(buf[0:n]))
n, err = conn.Write([]byte(this.UserName + "
"))
if nil != err {
log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Write, errInfo:", err)
return false
}
time.Sleep(time.Millisecond * 500)
n, err = conn.Read(buf[0:])
if nil != err {
log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Read, errInfo:", err)
return false
}
log.Print("4====",string(buf[0:n]))
n, err = conn.Write([]byte(this.Password+ "
"))
if nil != err {
log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Write, errInfo:", err)
return false
}
time.Sleep(time.Millisecond * 2000)
n, err = conn.Read(buf[0:])
if nil != err {
log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Read, errInfo:", err)
return false
}
log.Print("5====",string(buf[0:n]))
buf[0] = 0xff
buf[1] = 0xfc
buf[2] = 0x18
n, err = conn.Write(buf[0:3])
if nil != err {
log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Write, errInfo:", err)
return false
}
n, err = conn.Read(buf[0:])
if nil != err {
log.Print("pkg: model, func: telnetProtocolHandshake, method: conn.Read, errInfo:", err)
return false
}
log.Print("6====",string(buf[0:n]))
return true
}
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