--- /dev/null
+/*
+GoVPN -- simple secure free software virtual private network daemon
+Copyright (C) 2014-2016 Sergey Matveev <stargrave@stargrave.org>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package main
+
+import (
+ "bytes"
+ "log"
+ "net"
+ "time"
+
+ "cypherpunks.ru/govpn"
+)
+
+func startTCP() {
+ bind, err := net.ResolveTCPAddr("tcp", *bindAddr)
+ if err != nil {
+ log.Fatalln("Can not resolve bind address:", err)
+ }
+ listener, err := net.ListenTCP("tcp", bind)
+ if err != nil {
+ log.Fatalln("Can not listen on TCP:", err)
+ }
+ log.Println("Listening on TCP:" + *bindAddr)
+ go func() {
+ for {
+ conn, err := listener.AcceptTCP()
+ if err != nil {
+ log.Println("Error accepting TCP:", err)
+ continue
+ }
+ go handleTCP(conn)
+ }
+ }()
+}
+
+func handleTCP(conn net.Conn) {
+ addr := conn.RemoteAddr().String()
+ buf := make([]byte, govpn.EnclessEnlargeSize+2*govpn.MTUMax)
+ var n int
+ var err error
+ var prev int
+ var hs *govpn.Handshake
+ var ps *PeerState
+ var peer *govpn.Peer
+ var tap *govpn.TAP
+ var conf *govpn.PeerConf
+ for {
+ if prev == len(buf) {
+ break
+ }
+ conn.SetReadDeadline(time.Now().Add(time.Duration(govpn.TimeoutDefault) * time.Second))
+ n, err = conn.Read(buf[prev:])
+ if err != nil {
+ // Either EOFed or timeouted
+ break
+ }
+ prev += n
+ peerId := idsCache.Find(buf[:prev])
+ if peerId == nil {
+ continue
+ }
+ if hs == nil {
+ conf = confs[*peerId]
+ if conf == nil {
+ log.Println("Can not get peer configuration:", peerId.String())
+ break
+ }
+ hs = govpn.NewHandshake(addr, conn, conf)
+ }
+ peer = hs.Server(buf[:prev])
+ prev = 0
+ if peer == nil {
+ continue
+ }
+ hs.Zero()
+ log.Println("Peer handshake finished:", addr, peer.Id.String())
+ peersByIdLock.RLock()
+ addrPrev, exists := peersById[*peer.Id]
+ peersByIdLock.RUnlock()
+ if exists {
+ peersLock.Lock()
+ peers[addrPrev].terminator <- struct{}{}
+ tap = peers[addrPrev].tap
+ ps = &PeerState{
+ peer: peer,
+ tap: tap,
+ terminator: make(chan struct{}),
+ }
+ go peerReady(*ps)
+ peersByIdLock.Lock()
+ kpLock.Lock()
+ delete(peers, addrPrev)
+ delete(knownPeers, addrPrev)
+ peers[addr] = ps
+ knownPeers[addr] = &peer
+ peersById[*peer.Id] = addr
+ peersLock.Unlock()
+ peersByIdLock.Unlock()
+ kpLock.Unlock()
+ log.Println("Rehandshake processed:", peer.Id.String())
+ } else {
+ ifaceName, err := callUp(peer.Id)
+ if err != nil {
+ peer = nil
+ break
+ }
+ tap, err = govpn.TAPListen(ifaceName, peer.MTU)
+ if err != nil {
+ log.Println("Unable to create TAP:", err)
+ peer = nil
+ break
+ }
+ ps = &PeerState{
+ peer: peer,
+ tap: tap,
+ terminator: make(chan struct{}, 1),
+ }
+ go peerReady(*ps)
+ peersLock.Lock()
+ peersByIdLock.Lock()
+ kpLock.Lock()
+ peers[addr] = ps
+ peersById[*peer.Id] = addr
+ knownPeers[addr] = &peer
+ peersLock.Unlock()
+ peersByIdLock.Unlock()
+ kpLock.Unlock()
+ log.Println("Peer created:", peer.Id.String())
+ }
+ break
+ }
+ if hs != nil {
+ hs.Zero()
+ }
+ if peer == nil {
+ return
+ }
+
+ nonceExpectation := make([]byte, govpn.NonceSize)
+ peer.NonceExpectation(nonceExpectation)
+ prev = 0
+ var i int
+ for {
+ if prev == len(buf) {
+ break
+ }
+ conn.SetReadDeadline(time.Now().Add(conf.Timeout))
+ n, err = conn.Read(buf[prev:])
+ if err != nil {
+ // Either EOFed or timeouted
+ break
+ }
+ 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",
+ addr, peer.Id.String(),
+ )
+ break
+ }
+ peer.NonceExpectation(nonceExpectation)
+ copy(buf, buf[i+govpn.NonceSize:prev])
+ prev = prev - i - govpn.NonceSize
+ goto CheckMore
+ }
+ peer.Zero()
+}