package main
import (
+ "bytes"
"encoding/binary"
- "io"
"log"
"net"
+ "sync/atomic"
+ "time"
"govpn"
)
-// TCPSender prepends size prefix to each outgoing packet.
-type TCPSender struct {
- conn *net.TCPConn
-}
-
-func (c TCPSender) Write(data []byte) (int, error) {
- size := make([]byte, 2)
- binary.BigEndian.PutUint16(size, uint16(len(data)))
- return c.conn.Write(append(size, data...))
-}
-
-func startTCP() (io.Writer, chan []byte, chan struct{}) {
+func startTCP(timeouted, rehandshaking, termination chan struct{}) {
remote, err := net.ResolveTCPAddr("tcp", *remoteAddr)
if err != nil {
log.Fatalln("Can not resolve remote address:", err)
}
- c, err := net.DialTCP("tcp", nil, remote)
- conn := TCPSender{c}
+ conn, err := net.DialTCP("tcp", nil, remote)
if err != nil {
- log.Fatalln("Can not connect TCP:", err)
+ log.Fatalln("Can not connect to address:", err)
}
- sink := make(chan []byte)
- ready := make(chan struct{})
- go handleTCP(c, sink, ready)
- go func() { ready <- struct{}{} }()
- return conn, sink, ready
+ log.Println("Connected to TCP:" + *remoteAddr)
+ handleTCP(conn, timeouted, rehandshaking, termination)
}
-func handleTCP(conn *net.TCPConn, sink chan []byte, ready chan struct{}) {
- var err error
- var n int
- var sizeNbuf int
- sizeBuf := make([]byte, 2)
- var sizeNeed uint16
- var bufN uint16
+func handleTCP(conn *net.TCPConn, timeouted, rehandshaking, termination chan struct{}) {
+ hs := govpn.HandshakeStart(*remoteAddr, conn, conf)
buf := make([]byte, govpn.MTU)
+ var n int
+ var err error
+ var prev int
+ var peer *govpn.Peer
+ var terminator chan struct{}
+HandshakeCycle:
for {
- <-ready
- if sizeNbuf != 2 {
- n, err = conn.Read(sizeBuf[sizeNbuf:2])
- if err != nil {
- break
- }
- sizeNbuf += n
- if sizeNbuf != 2 {
- sink <- nil
- continue
- }
- sizeNeed = binary.BigEndian.Uint16(sizeBuf)
- if int(sizeNeed) > govpn.MTU-2 {
- log.Println("Invalid TCP size, skipping")
- sizeNbuf = 0
- sink <- nil
- continue
- }
- bufN = 0
+ select {
+ case <-termination:
+ break HandshakeCycle
+ default:
+ }
+ if prev == govpn.MTU {
+ log.Println("Timeouted waiting for the packet")
+ timeouted <- struct{}{}
+ break HandshakeCycle
+ }
+
+ conn.SetReadDeadline(time.Now().Add(time.Duration(timeout) * time.Second))
+ n, err = conn.Read(buf[prev:])
+ if err != nil {
+ log.Println("Connection timeouted")
+ timeouted <- struct{}{}
+ break HandshakeCycle
+ }
+
+ prev += n
+ peerId := idsCache.Find(buf[:prev])
+ if peerId == nil {
+ continue
+ }
+ peer = hs.Client(buf[:prev])
+ prev = 0
+ if peer == nil {
+ continue
}
- ReadMore:
- if sizeNeed != bufN {
- n, err = conn.Read(buf[bufN:sizeNeed])
- if err != nil {
- break
+ log.Println("Handshake completed")
+ knownPeers = govpn.KnownPeers(map[string]**govpn.Peer{*remoteAddr: &peer})
+ if firstUpCall {
+ go govpn.ScriptCall(*upPath, *ifaceName)
+ firstUpCall = false
+ }
+ hs.Zero()
+ terminator = make(chan struct{})
+ go func() {
+ heartbeat := time.NewTicker(peer.Timeout)
+ var data []byte
+ Processor:
+ for {
+ select {
+ case <-heartbeat.C:
+ peer.EthProcess(nil)
+ case <-terminator:
+ break Processor
+ case data = <-tap.Sink:
+ peer.EthProcess(data)
+ }
}
- bufN += uint16(n)
- goto ReadMore
+ heartbeat.Stop()
+ peer.Zero()
+ }()
+ break HandshakeCycle
+ }
+ if hs != nil {
+ hs.Zero()
+ }
+ if peer == nil {
+ return
+ }
+
+ nonceExpectation := make([]byte, govpn.NonceSize)
+ binary.BigEndian.PutUint64(nonceExpectation, peer.NonceExpect)
+ peer.NonceCipher.Encrypt(nonceExpectation, nonceExpectation)
+ prev = 0
+ var i int
+TransportCycle:
+ for {
+ select {
+ case <-termination:
+ break TransportCycle
+ default:
}
- sizeNbuf = 0
- sink <- buf[:sizeNeed]
+ if prev == govpn.MTU {
+ log.Println("Timeouted waiting for the packet")
+ timeouted <- struct{}{}
+ break TransportCycle
+ }
+ conn.SetReadDeadline(time.Now().Add(time.Duration(timeout) * time.Second))
+ n, err = conn.Read(buf[prev:])
+ if err != nil {
+ log.Println("Connection timeouted")
+ timeouted <- struct{}{}
+ break TransportCycle
+ }
+ prev += n
+ CheckMore:
+ if prev < govpn.MinPktLength {
+ continue
+ }
+ i = bytes.Index(buf[:prev], nonceExpectation)
+ if i == -1 {
+ continue
+ }
+ if !peer.PktProcess(buf[:i+govpn.NonceSize], tap, false) {
+ log.Println("Unauthenticated packet, dropping connection")
+ timeouted <- struct{}{}
+ break TransportCycle
+ }
+ if atomic.LoadInt64(&peer.BytesIn)+atomic.LoadInt64(&peer.BytesOut) > govpn.MaxBytesPerKey {
+ log.Println("Need rehandshake")
+ rehandshaking <- struct{}{}
+ break TransportCycle
+ }
+ binary.BigEndian.PutUint64(nonceExpectation, peer.NonceExpect)
+ peer.NonceCipher.Encrypt(nonceExpectation, nonceExpectation)
+ copy(buf, buf[i+govpn.NonceSize:prev])
+ prev = prev - i - govpn.NonceSize
+ goto CheckMore
+ }
+ if terminator != nil {
+ terminator <- struct{}{}
}
+ peer.Zero()
+ conn.Close()
}