func startUDP() {
bind, err := net.ResolveUDPAddr("udp", *bindAddr)
if err != nil {
log.Fatalln("Can not resolve bind address:", err)
}
conn, err := net.ListenUDP("udp", bind)
if err != nil {
log.Fatalln("Can not listen on UDP:", err)
}
log.Println("Listening on UDP:" + *bindAddr)
udpBufs <- make([]byte, govpn.MTU)
go func() {
var buf []byte
var raddr *net.UDPAddr
var addr string
var n int
var err error
var ps *PeerState
var hs *govpn.Handshake
var addrPrev string
var exists bool
var peerId *govpn.PeerId
var peer *govpn.Peer
var conf *govpn.PeerConf
for {
buf = <-udpBufs
n, raddr, err = conn.ReadFromUDP(buf)
if err != nil {
log.Println("Unexpected error when receiving", err)
break
}
addr = raddr.String()
peersLock.RLock()
ps, exists = peers[addr]
peersLock.RUnlock()
if !exists {
goto CheckHandshake
}
go func(ps *govpn.Peer, tap *govpn.TAP, buf []byte, n int) {
peer.PktProcess(buf[:n], tap, true)
udpBufs <- buf
}(ps.peer, ps.tap, buf, n)
continue
CheckHandshake:
hsLock.RLock()
hs, exists = handshakes[addr]
hsLock.RUnlock()
if !exists {
goto CheckID
}
peer = hs.Server(buf[:n])
if peer == nil {
goto Finished
}
log.Println("Peer handshake finished:", addr, peer.Id.String())
hs.Zero()
hsLock.Lock()
delete(handshakes, addr)
hsLock.Unlock()
go func() {
udpBufs <- make([]byte, govpn.MTU)
udpBufs <- make([]byte, govpn.MTU)
}()
peersByIdLock.RLock()
addrPrev, exists = peersById[*peer.Id]
peersByIdLock.RUnlock()
if exists {
peersLock.Lock()
peers[addrPrev].terminator <- struct{}{}
ps = &PeerState{
peer: peer,
tap: peers[addrPrev].tap,
terminator: make(chan struct{}),
}
go func(ps PeerState) {
peerReady(ps)
<-udpBufs
<-udpBufs
}(*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 {
go func(addr string, peer *govpn.Peer) {
ifaceName, err := callUp(peer.Id)
if err != nil {
return
}
tap, err := govpn.TAPListen(ifaceName)
if err != nil {
log.Println("Unable to create TAP:", err)
return
}
ps = &PeerState{
peer: peer,
tap: tap,
terminator: make(chan struct{}),
}
go func(ps PeerState) {
peerReady(ps)
<-udpBufs
<-udpBufs
}(*ps)
peersLock.Lock()
peersByIdLock.Lock()
kpLock.Lock()
peers[addr] = ps
knownPeers[addr] = &peer
peersById[*peer.Id] = addr
peersLock.Unlock()
peersByIdLock.Unlock()
kpLock.Unlock()
log.Println("Peer created:", peer.Id.String())
}(addr, peer)
}
goto Finished
CheckID:
peerId = idsCache.Find(buf[:n])
if peerId == nil {
log.Println("Unknown identity from:", addr)
goto Finished
}
conf = confs[*peerId]
if conf == nil {
log.Println("Unable to get peer configuration:", peerId.String())
goto Finished
}
hs = govpn.NewHandshake(
addr,
UDPSender{conn: conn, addr: raddr},
conf,
)
hs.Server(buf[:n])
hsLock.Lock()
handshakes[addr] = hs
hsLock.Unlock()
Finished:
udpBufs <- buf
}
}()
}
func main() {
flag.Parse()
timeout := time.Second * time.Duration(govpn.TimeoutDefault)
log.SetFlags(log.Ldate | log.Lmicroseconds | log.Lshortfile)
log.Println(govpn.VersionGet())
govpn.MTU = *mtu
govpn.PeersInit(*peersPath)
if *egdPath != "" {
log.Println("Using", *egdPath, "EGD")
govpn.EGDInit(*egdPath)
}
sink := make(chan Pkt)
switch *proto {
case "udp":
startUDP(sink)
case "tcp":
startTCP(sink)
case "all":
startUDP(sink)
startTCP(sink)
default:
log.Fatalln("Unknown protocol specified")
}
termSignal := make(chan os.Signal, 1)
signal.Notify(termSignal, os.Interrupt, os.Kill)
hsHeartbeat := time.Tick(timeout)
go func() { <-hsHeartbeat }()
var state *govpn.Handshake
var peerState *PeerState
var peer *govpn.Peer
var exists bool
states := make(map[string]*govpn.Handshake)
peers := make(map[string]*PeerState)
peerReadySink := make(chan PeerReadyEvent)
knownPeers := govpn.KnownPeers(make(map[string]**govpn.Peer))
var peerReady PeerReadyEvent
var pkt Pkt
var ethEvent EthEvent
var peerId *govpn.PeerId
var peerConf *govpn.PeerConf
var handshakeProcessForce bool
ethSink := make(chan EthEvent)
log.Println("Max MTU on TAP interface:", govpn.TAPMaxMTU())
if *stats != "" {
log.Println("Stats are going to listen on", *stats)
statsPort, err := net.Listen("tcp", *stats)
if err != nil {
log.Fatalln("Can not listen on stats port:", err)
}
go govpn.StatsProcessor(statsPort, &knownPeers)
}
if *proxy != "" {
go proxyStart(sink)
}
log.Println("Server started")
MainCycle:
for {
select {
case <-termSignal:
break MainCycle
case <-hsHeartbeat:
now := time.Now()
for addr, hs := range states {
if hs.LastPing.Add(timeout).Before(now) {
log.Println("Deleting handshake state", addr)
hs.Zero()
delete(states, addr)
}
}
for addr, state := range peers {
if state.peer.LastPing.Add(timeout).Before(now) {
log.Println("Deleting peer", state.peer)
delete(peers, addr)
delete(knownPeers, addr)
downPath := path.Join(
govpn.PeersPath,
state.peer.Id.String(),
"down.sh",
)
go govpn.ScriptCall(downPath, state.tap.Name)
state.terminate <- struct{}{}
state.peer.Zero()
}
}
case peerReady = <-peerReadySink:
for addr, state := range peers {
if state.tap.Name != peerReady.iface {
continue
}
delete(peers, addr)
delete(knownPeers, addr)
state.terminate <- struct{}{}
state.peer.Zero()
break
}
state := NewPeerState(peerReady.peer, peerReady.iface)
if state == nil {
continue
}
peers[peerReady.peer.Addr] = state
knownPeers[peerReady.peer.Addr] = &peerReady.peer
states[peerReady.peer.Addr].Zero()
delete(states, peerReady.peer.Addr)
log.Println("Registered interface", peerReady.iface, "with peer", peer)
go func(state *PeerState) {
for data := range state.sink {
ethSink <- EthEvent{
peer: state.peer,
data: data,
ready: state.ready,
}
}
}(state)
case ethEvent = <-ethSink:
if s, exists := peers[ethEvent.peer.Addr]; !exists || s.peer != ethEvent.peer {
continue
}
ethEvent.peer.EthProcess(ethEvent.data, ethEvent.ready)
case pkt = <-sink:
if pkt.data == nil {
pkt.ready <- struct{}{}
continue
}
handshakeProcessForce = false
HandshakeProcess:
if _, exists = peers[pkt.addr]; handshakeProcessForce || !exists {
peerId = govpn.IDsCache.Find(pkt.data)
if peerId == nil {
log.Println("Unknown identity from", pkt.addr)
pkt.ready <- struct{}{}
continue
}
peerConf = peerId.Conf()
if peerConf == nil {
log.Println("Can not get peer configuration", peerId.String())
pkt.ready <- struct{}{}
continue
}
state, exists = states[pkt.addr]
if !exists {
state = govpn.HandshakeNew(pkt.addr, pkt.conn, peerConf)
states[pkt.addr] = state
}
peer = state.Server(pkt.data)
if peer != nil {
log.Println("Peer handshake finished", peer)
if _, exists = peers[pkt.addr]; exists {
go func() {
peerReadySink <- PeerReadyEvent{
peer, peers[pkt.addr].tap.Name,
}
}()
} else {
go func() {
upPath := path.Join(govpn.PeersPath, peer.Id.String(), "up.sh")
result, err := govpn.ScriptCall(upPath, "")
if err != nil {
return
}
sepIndex := bytes.Index(result, []byte{'\n'})
if sepIndex < 0 {
sepIndex = len(result)
}
ifaceName := string(result[:sepIndex])
peerReadySink <- PeerReadyEvent{peer, ifaceName}
}()
}
}
if !handshakeProcessForce {
pkt.ready <- struct{}{}
}
continue
}
peerState, exists = peers[pkt.addr]
if !exists {
pkt.ready <- struct{}{}
continue
}
// If it fails during processing, then try to work with it
// as with handshake packet
if !peerState.peer.PktProcess(pkt.data, peerState.tap, pkt.ready) {
handshakeProcessForce = true
goto HandshakeProcess
}
}
}
}
func handleTCP(conn net.Conn) {
addr := conn.RemoteAddr().String()
buf := make([]byte, govpn.MTU)
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 == govpn.MTU {
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 {
break
}
tap, err = govpn.TAPListen(ifaceName)
if err != nil {
log.Println("Unable to create TAP:", err)
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 == govpn.MTU {
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()
}