Add vendor (steam)

vendor/github.com/Philipp15b/go-steam/connection.go

@@ -0,0 +1,127 @@
+package steam
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"net"
+	"sync"
+
+	"github.com/Philipp15b/go-steam/cryptoutil"
+	. "github.com/Philipp15b/go-steam/protocol"
+)
+
+type connection interface {
+	Read() (*Packet, error)
+	Write([]byte) error
+	Close() error
+	SetEncryptionKey([]byte)
+	IsEncrypted() bool
+}
+
+const tcpConnectionMagic uint32 = 0x31305456 // "VT01"
+
+type tcpConnection struct {
+	conn        *net.TCPConn
+	ciph        cipher.Block
+	cipherMutex sync.RWMutex
+}
+
+func dialTCP(laddr, raddr *net.TCPAddr) (*tcpConnection, error) {
+	conn, err := net.DialTCP("tcp", laddr, raddr)
+	if err != nil {
+		return nil, err
+	}
+
+	return &tcpConnection{
+		conn: conn,
+	}, nil
+}
+
+func (c *tcpConnection) Read() (*Packet, error) {
+	// All packets begin with a packet length
+	var packetLen uint32
+	err := binary.Read(c.conn, binary.LittleEndian, &packetLen)
+	if err != nil {
+		return nil, err
+	}
+
+	// A magic value follows for validation
+	var packetMagic uint32
+	err = binary.Read(c.conn, binary.LittleEndian, &packetMagic)
+	if err != nil {
+		return nil, err
+	}
+	if packetMagic != tcpConnectionMagic {
+		return nil, fmt.Errorf("Invalid connection magic! Expected %d, got %d!", tcpConnectionMagic, packetMagic)
+	}
+
+	buf := make([]byte, packetLen, packetLen)
+	_, err = io.ReadFull(c.conn, buf)
+	if err == io.ErrUnexpectedEOF {
+		return nil, io.EOF
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	// Packets after ChannelEncryptResult are encrypted
+	c.cipherMutex.RLock()
+	if c.ciph != nil {
+		buf = cryptoutil.SymmetricDecrypt(c.ciph, buf)
+	}
+	c.cipherMutex.RUnlock()
+
+	return NewPacket(buf)
+}
+
+// Writes a message. This may only be used by one goroutine at a time.
+func (c *tcpConnection) Write(message []byte) error {
+	c.cipherMutex.RLock()
+	if c.ciph != nil {
+		message = cryptoutil.SymmetricEncrypt(c.ciph, message)
+	}
+	c.cipherMutex.RUnlock()
+
+	err := binary.Write(c.conn, binary.LittleEndian, uint32(len(message)))
+	if err != nil {
+		return err
+	}
+	err = binary.Write(c.conn, binary.LittleEndian, tcpConnectionMagic)
+	if err != nil {
+		return err
+	}
+
+	_, err = c.conn.Write(message)
+	return err
+}
+
+func (c *tcpConnection) Close() error {
+	return c.conn.Close()
+}
+
+func (c *tcpConnection) SetEncryptionKey(key []byte) {
+	c.cipherMutex.Lock()
+	defer c.cipherMutex.Unlock()
+	if key == nil {
+		c.ciph = nil
+		return
+	}
+	if len(key) != 32 {
+		panic("Connection AES key is not 32 bytes long!")
+	}
+
+	var err error
+	c.ciph, err = aes.NewCipher(key)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func (c *tcpConnection) IsEncrypted() bool {
+	c.cipherMutex.RLock()
+	defer c.cipherMutex.RUnlock()
+	return c.ciph != nil
+}