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base.go
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base.go
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package mnet_core_udp
import (
"../../../../../core"
"../../../../../util"
"../../../../config"
"../../../../runtime"
"../../../if"
"../../../packet/filter"
"../../../vars"
"../../base"
"crypto/hmac"
"crypto/sha256"
"encoding/hex"
"errors"
"fmt"
"github.com/MarconiProtocol/gopacket"
"github.com/MarconiProtocol/gopacket/layers"
m_packet_filter "github.com/MarconiProtocol/sdk/packet/filter"
"net"
"strings"
"sync"
"time"
)
type UDPTransport struct{}
var once sync.Once
var udpTransport *UDPTransport
func GetUDPTransport() *UDPTransport {
once.Do(func() {
udpTransport = &UDPTransport{}
})
return udpTransport
}
func (udpt *UDPTransport) ListenAndTransmit(
localIpAddr string, localPort string,
remoteIpAddr string, remotePort string,
tapConn *mnet_if.Interface,
key []byte, dataKey *[]byte,
isSecure bool, isTun bool,
listenSignalChannel chan string, transmitSignalChannel chan string) (net.Conn, error) {
/* Parse & resolve the peer address, if it was provided */
var peerIpAddr *net.UDPAddr
var peerDiscoveryChannel chan net.UDPAddr
//Parse & resolve local address
localUDPAddr, err := net.ResolveUDPAddr("udp", localIpAddr+":"+localPort)
if err != nil {
return nil, errors.New(fmt.Sprintf("Failed to resolve local addr %s:%s - err: %s", localIpAddr, localPort, err))
}
//Create a UDP physical connection
physConn, err := net.ListenUDP("udp", localUDPAddr)
if err != nil {
return nil, errors.New(fmt.Sprintf("Failed to create UDP socket %s - err: %s", localUDPAddr, err))
}
if remoteIpAddr != "" {
remoteTarget := remoteIpAddr + ":" + remotePort
peerIpAddr, err = net.ResolveUDPAddr("udp", remoteTarget)
if err != nil {
return nil, errors.New(fmt.Sprintf("Failed to resolve remote addr %s:%s - err: %s", remoteIpAddr, remotePort, err))
}
peerDiscoveryChannel = nil
} else {
//Otherwise, prepare a channel that the listen() goroutine will forward discovered peers through
peerIpAddr = nil
peerDiscoveryChannel = make(chan net.UDPAddr)
}
go udpt.Listen(physConn, tapConn, peerIpAddr, key, dataKey, isSecure, peerDiscoveryChannel, isTun, listenSignalChannel)
go udpt.Transmit(physConn, tapConn, peerIpAddr, key, dataKey, isSecure, peerDiscoveryChannel, isTun, transmitSignalChannel)
return physConn, nil
}
//To forward data from physical interface to tap/tun/virtual link interface
func (udpt *UDPTransport) Listen(physConn *net.UDPConn, tapConn *mnet_if.Interface, peerAddr *net.UDPAddr, key []byte,
dataKey *[]byte, isSecure bool, peerDiscoveryChannel chan net.UDPAddr, isTun bool, signalChannel chan string) {
packet := make([]byte, mnet_vars.UDP_MTU)
var decapsulatedFrames []byte
var invalid error = nil
var currentPeerAddr net.UDPAddr
var peerDiscovery bool
hmacH := hmac.New(sha256.New, key)
/* If a peer was specified, fill in our peer information */
if peerAddr != nil {
currentPeerAddr.IP = peerAddr.IP
currentPeerAddr.Port = peerAddr.Port
mnet_core_base.Log.Debugf("Starting udp->tap forwarding with peer %s:%d...", currentPeerAddr.IP, currentPeerAddr.Port)
peerDiscovery = false
} else {
mnet_core_base.Log.Debug("Starting udp->tap forwarding with peer discovery...")
peerDiscovery = true
}
var crashCounterInterface uint = 0
filterManager := mpacket_filter.GetFilterManagerInstance()
resultChannel := make(chan mpacket_filter.PacketFilterResult)
for {
select {
case msg := <-signalChannel:
if strings.Compare(msg, "quit") == 0 {
return
}
default:
/* Receive an encapsulated frame packet through UDP */
physConn.SetDeadline(time.Now().Add(mnet_core_base.SOCKET_TIMEOUT_SECONDS * time.Second))
n, raddr, err := physConn.ReadFromUDP(packet)
if err != nil {
mnet_core_base.Log.Warnf("Error reading from UDP socket: %s", err)
continue
}
/* If peer discovery is off, ensure the received packge is from our specified peer */
if !peerDiscovery && (!raddr.IP.Equal(currentPeerAddr.IP) || raddr.Port != currentPeerAddr.Port) {
continue
}
mnet_core_base.Log.Debug("<- udp | Encapsulated frame:")
mnet_core_base.Log.Debugf(" | from Peer %s:%d", raddr.IP, raddr.Port)
mnet_core_base.Log.Debugf("%s", hex.Dump(packet[0:n]))
/* Decapsulate the frame, skip it if it's invalid */
decapsulatedFrames, invalid = mnet_core_base.DecodeFrame(packet[0:n], hmacH)
if invalid != nil {
mnet_core_base.Log.Debugf("<- udp | Frame discarded! Size: %d, Reason: %s", n, invalid.Error())
mnet_core_base.Log.Debugf(" | from Peer %s:%d", raddr.IP, raddr.Port)
mnet_core_base.Log.Debug(hex.Dump(packet[0:n]))
continue
}
decapsulatedFramesDecoded := decapsulatedFrames
if isSecure {
var crypter mutil.SymmetricCrypter = mutil.NewAesCrypter(*dataKey)
tmpFrame, err := crypter.Decrypt(decapsulatedFrames)
decapsulatedFramesDecoded = make([]byte, len(tmpFrame))
decapsulatedFramesDecoded = tmpFrame
if err != nil {
mnet_core_base.Log.Fatal("Error: decrypted:", len(decapsulatedFramesDecoded), "org/encrypted:", len(decapsulatedFrames), "n", n, "err:", err)
} else {
mnet_core_base.Log.Debug("decrypted:", len(decapsulatedFramesDecoded), "org/encrypted:", len(decapsulatedFrames), "after l2 checksum strip:", decapsulatedFrames, "n:", n)
}
} else {
mnet_core_base.Log.Debug("decrypt: no encryption enabled")
}
/* If peer discovery is on and the peer is new, save the discovered peer */
if peerDiscovery && (!raddr.IP.Equal(currentPeerAddr.IP) || raddr.Port != currentPeerAddr.Port) {
currentPeerAddr.IP = raddr.IP
currentPeerAddr.Port = raddr.Port
/* Send the new peer info to our transmit() goroutine via channel */
peerDiscoveryChannel <- currentPeerAddr
mnet_core_base.Log.Debugf("Discovered peer %s:%d!", currentPeerAddr.IP, currentPeerAddr.Port)
}
mnet_core_base.Log.Debug("-> tap | Decapsulated frame from peer:")
mnet_core_base.Log.Debug(hex.Dump(decapsulatedFramesDecoded))
mnet_core_base.Log.Debug("decoded frame:", decapsulatedFramesDecoded, len(decapsulatedFramesDecoded))
// only ask filterManager to process packets if packet filtering is enabled
if mconfig.GetAppConfig().Global.Packet_Filters_Enabled {
// Marshall bytes into gopacket
ethPacket := gopacket.NewPacket(decapsulatedFramesDecoded, layers.LayerTypeEthernet, gopacket.Default)
// Process the packet
go filterManager.ProcessPacket(ðPacket, &resultChannel)
// Wait for the signal from filter manager packet signal channel
result := <-resultChannel
switch result.Action {
case m_packet_filter.ACCEPT:
// No-op
case m_packet_filter.DROP:
mnet_core_base.Log.Debug("Dropped packet - ", result.FilterResponse.Msg)
// Drop the packet by not forwarding it on to virtual device
continue
}
}
if isTun {
//NOTE: darwin/osx does not need to go though clean up path since it requires ot have extra 4 bytes on header
if mruntime.GetMRuntime().GetRuntimeOS() != mcore.TYPE_OS_DARWIN {
//for now try slice and repack
adjustedFrame := decapsulatedFramesDecoded[4:] // bsd link layer adjustment
decapsulatedFramesDecoded = make([]byte, len(adjustedFrame))
decapsulatedFramesDecoded = adjustedFrame
} else {
BSDLinkLayerBytes := []byte{0, 0, 0, 2}
possibleBSDLinkLayerBytes := decapsulatedFramesDecoded[:4]
_ = BSDLinkLayerBytes
_ = possibleBSDLinkLayerBytes
mnet_core_base.Log.Debug("Regular Linux style tun traffic, not BSD style.")
}
} else {
mnet_core_base.Log.Debug("net_core/listen: mode: tap")
}
_, err = tapConn.Write(decapsulatedFramesDecoded)
if err != nil {
crashCounterInterface++
mnet_core_base.Log.Debug("interface: file", tapConn.GetFdOS())
mnet_core_base.Log.Debug("interface: pointer", tapConn.GetFd())
mnet_core_base.Log.Debug("decoded frame:", decapsulatedFramesDecoded, len(decapsulatedFramesDecoded))
mnet_core_base.Log.Error("Error writing to tap device:", err)
}
}
}
}
//To forward data from tap/tun/virtual link interface to physical interface
func (udpt *UDPTransport) Transmit(physConn *net.UDPConn, tapConn *mnet_if.Interface, peerAddr *net.UDPAddr, key []byte, dataKey *[]byte,
isSecure bool, peerDiscoveryChannel chan net.UDPAddr, isTun bool, signalChannel chan string) {
/* Raw tap frame received */
//var frame []byte
//NOTE: this value matter with MTU since it's writing into peer and this buffer is max value
// but this might not matter with tun interace. try with 1500 - pedding for encyrptions
frame := make([]byte, mnet_vars.TAP_MTU+14)
/* Encapsulated frame and error */
var encapsulatedFrames []byte
var invalid error = nil
/* Peer address */
var currentPeerAddr net.UDPAddr
var peerDiscovery bool
//var currentBlockTimeIndex uint16
/* Initialize our HMAC-SHA256 hash context */
hmacH := hmac.New(sha256.New, key)
/* If a peer was specified, fill in our peer information */
if peerAddr != nil {
currentPeerAddr.IP = peerAddr.IP
currentPeerAddr.Port = peerAddr.Port
peerDiscovery = false
} else {
peerDiscovery = true
/* Otherwise, wait for the listen() goroutine to discover a peer */
currentPeerAddr = <-peerDiscoveryChannel
}
mnet_core_base.Log.Debugf("Starting tap->udp forwarding with peer %s:%d...", currentPeerAddr.IP, currentPeerAddr.Port)
for {
select {
case msg := <-signalChannel:
if strings.Compare(msg, "quit") == 0 {
return
}
default:
/* If peer discovery is on, check for any newly discovered peers */
if peerDiscovery {
select {
case currentPeerAddr = <-peerDiscoveryChannel:
mnet_core_base.Log.Debugf("Starting tap->udp forwarding with peer %s:%d...", currentPeerAddr.IP, currentPeerAddr.Port)
default:
}
}
/* Read a raw frame from our tap device */
n, err := tapConn.Read(frame)
if err != nil {
mnet_core_base.Log.Debug("Tap/Tun Interface Read: ", n)
mnet_core_base.Log.Debug("Interface:", tapConn.GetFdOS())
mnet_core_base.Log.Fatalf("Error reading from tap device: %s", err)
}
mnet_core_base.Log.Debug("<- tap | Plaintext frame to peer:")
mnet_core_base.Log.Debugf("%s", hex.Dump(frame[0:n]))
mnet_core_base.Log.Debug("raw frame: ", frame, len(frame))
rawFrame := frame[:n]
if isTun {
// we do not need to inject with DARWIN/OSX system since system will add extra 4 bytes
if mruntime.GetMRuntime().GetRuntimeOS() != mcore.TYPE_OS_DARWIN {
//for now try slice and repack
adjustedFrame := append([]byte{0, 0, 0, 2}, rawFrame...)
rawFrame = make([]byte, len(adjustedFrame))
rawFrame = adjustedFrame
}
} else {
mnet_core_base.Log.Debug("net_core/transmit: mode: tap")
}
//encryption on data
if isSecure {
var crypter mutil.SymmetricCrypter = mutil.NewAesCrypter(*dataKey)
dataFrame, err := crypter.Encrypt(rawFrame)
/* Encapsulate the frame, skip it if it's invalid */
encapsulatedFrames, invalid = mnet_core_base.EncodeFrame(dataFrame, hmacH)
if err != nil {
mnet_core_base.Log.Fatal("Error: encrypted: ", len(dataFrame), "org:", len(rawFrame), "err:", err)
} else {
mnet_core_base.Log.Debug("encrypted: ", len(dataFrame), "org:", len(rawFrame))
}
} else {
mnet_core_base.Log.Debug("encrypt: no encryption enabled")
/* Encapsulate the frame, skip it if it's invalid */
encapsulatedFrames, invalid = mnet_core_base.EncodeFrame(rawFrame, hmacH)
}
if invalid != nil {
mnet_core_base.Log.Debugf("-> udp | Frame discarded! Size: %d, Reason: %s", n, invalid.Error())
mnet_core_base.Log.Debug(hex.Dump(rawFrame))
continue
}
mnet_core_base.Log.Debug("-> udp | Encapsulated frame to peer:", currentPeerAddr.IP.String())
mnet_core_base.Log.Debug(hex.Dump(encapsulatedFrames))
mnet_core_base.Log.Debug("encapsulated encrypted frame: ", encapsulatedFrames, len(encapsulatedFrames))
physConn.SetDeadline(time.Now().Add(mnet_core_base.SOCKET_TIMEOUT_SECONDS * time.Second))
_, err = physConn.WriteToUDP(encapsulatedFrames, ¤tPeerAddr)
if err != nil {
mnet_core_base.Log.Warnf("Error writing to UDP socket: %s", err)
}
}
}
}