From fa15141870988f2b5e87852186561d2f605f3b09 Mon Sep 17 00:00:00 2001
From: Tnze <cjd001113@outlook.com>
Date: Tue, 30 Jul 2019 01:33:18 +0800
Subject: [PATCH] rcon connection

---
 net/rcon.go      | 83 ++++++++++++++++++++++++++++++++++++++++++++++++
 net/rcon_test.go |  1 +
 2 files changed, 84 insertions(+)
 create mode 100644 net/rcon.go
 create mode 100644 net/rcon_test.go

diff --git a/net/rcon.go b/net/rcon.go
new file mode 100644
index 0000000..f2a964b
--- /dev/null
+++ b/net/rcon.go
@@ -0,0 +1,83 @@
+package net
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"math/rand"
+	"net"
+)
+
+func DialRCON(addr string, password string) (c *RCONConn, err error) {
+	c = &RCONConn{reqID: rand.Int31()}
+
+	c.Conn, err = net.Dial("tcp", addr)
+	if err != nil {
+		return
+	}
+
+	//Login
+	err = c.WritePacket(3, password)
+	if err != nil {
+		return
+	}
+
+	t, p, err := c.ReadPacket()
+	if err != nil {
+		return
+	}
+	fmt.Print(t, p)
+
+	return
+}
+
+type RCONConn struct {
+	net.Conn
+	reqID int32
+}
+
+func (c *RCONConn) ReadPacket() (Type int32, Payload string, err error) {
+	//read packet length
+	var Length int32
+	err = binary.Read(c, binary.LittleEndian, &Length)
+	if err != nil {
+		return
+	}
+
+	//read packet data
+	buf := make([]byte, Length)
+	err = binary.Read(c, binary.LittleEndian, &buf)
+	if err != nil {
+		return
+	}
+
+	//check length
+	if Length < 4+4+0+2 {
+		err = errors.New("packet too short")
+		return
+	}
+
+	RequestID := int32(binary.LittleEndian.Uint32(buf[:4]))
+	Type = int32(binary.LittleEndian.Uint32(buf[4:8]))
+	Payload = string(buf[8 : Length-2])
+
+	if RequestID == -1 {
+		err = errors.New("login fail")
+	} else if RequestID != c.reqID {
+		err = errors.New("request ID not match")
+	}
+
+	return
+}
+
+func (c *RCONConn) WritePacket(Type int32, Payload string) error {
+	err := binary.Write(c, binary.LittleEndian, []interface{}{
+		int32(4 + 4 + len(Payload) + 2), //Length
+		c.reqID,                         //Request ID
+		Type,                            //Type
+		[]byte(Payload),                 //Payload
+		[2]byte{0, 0},                   //pad
+	})
+
+	return err
+}
diff --git a/net/rcon_test.go b/net/rcon_test.go
new file mode 100644
index 0000000..9d9f1a1
--- /dev/null
+++ b/net/rcon_test.go
@@ -0,0 +1 @@
+package net