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.MTUMax)
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.MTUMax)
udpBufs <- make([]byte, govpn.MTUMax)
}()
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, peer.MTU)
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 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()
}