func (r *Router) routePacket(pkt []byte, conn *net.UDPConn) {
if len(pkt) < minIP4HdrSize {
log.V(1).Infof("Packet too small (%d bytes), unable to route", len(pkt))
return
}
r.mux.Lock()
defer r.mux.Unlock()
dstIP := ip.FromBytes(pkt[16:20])
for i, re := range r.routes {
if re.sn.Contains(dstIP) {
nbytes, err := conn.WriteToUDP(pkt, re.addr)
switch {
case err != nil:
log.V(1).Info("UDP send failed with: ", err)
case nbytes != len(pkt):
log.V(1).Infof("Was only able to UDP send %d out of %d bytes to %s: ", nbytes, len(pkt), re.addr.IP)
}
// packets for same dest tend to come in burst. swap to front make it faster for subsequent ones
if i != 0 {
r.routes[0], r.routes[i] = r.routes[i], r.routes[0]
}
return
}
}
log.V(1).Info("No route found for ", dstIP)
}
func proxyUdpToTun(conn *net.UDPConn, tun *os.File, tunMTU uint) {
pkt := make([]byte, tunMTU)
for {
nrecv, err := conn.Read(pkt)
if err != nil {
log.V(1).Info("Error reading from socket: ", err)
} else {
nsent, err := tun.Write(pkt[:nrecv])
switch {
case err != nil:
log.V(1).Info("Error writing to TUN device: ", err)
case nsent != nrecv:
log.V(1).Infof("Was only able to write %d out of %d bytes to TUN device: ", nsent, nrecv)
}
}
}
}
func proxyTunToUdp(r *Router, tun *os.File, conn *net.UDPConn, tunMTU uint) {
pkt := make([]byte, tunMTU)
for {
nbytes, err := tun.Read(pkt)
if err != nil {
log.V(1).Info("Error reading from TUN device: ", err)
} else {
r.routePacket(pkt[:nbytes], conn)
}
}
}
func runCProxy(tun *os.File, conn *os.File, ctl *os.File, tunIP ip.IP4, tunMTU uint) {
var log_errors int
if log.V(1) {
log_errors = 1
}
C.run_proxy(
C.int(tun.Fd()),
C.int(conn.Fd()),
C.int(ctl.Fd()),
C.in_addr_t(tunIP.NetworkOrder()),
C.size_t(tunMTU),
C.int(log_errors),
)
}