EtherGuard-VPN/device/receive.go
2021-12-03 20:16:18 +00:00

609 lines
16 KiB
Go

/* SPDX-License-Identifier: MIT
*
* Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
*/
package device
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"net"
"strconv"
"sync"
"sync/atomic"
"time"
"github.com/google/gopacket"
"github.com/google/gopacket/layers"
"golang.org/x/crypto/chacha20poly1305"
"github.com/KusakabeSi/EtherGuard-VPN/conn"
"github.com/KusakabeSi/EtherGuard-VPN/mtypes"
"github.com/KusakabeSi/EtherGuard-VPN/path"
"github.com/KusakabeSi/EtherGuard-VPN/tap"
)
type QueueHandshakeElement struct {
msgType path.Usage
packet []byte
endpoint conn.Endpoint
buffer *[MaxMessageSize]byte
}
type QueueInboundElement struct {
Type path.Usage
sync.Mutex
buffer *[MaxMessageSize]byte
packet []byte
counter uint64
keypair *Keypair
endpoint conn.Endpoint
}
// clearPointers clears elem fields that contain pointers.
// This makes the garbage collector's life easier and
// avoids accidentally keeping other objects around unnecessarily.
// It also reduces the possible collateral damage from use-after-free bugs.
func (elem *QueueInboundElement) clearPointers() {
elem.buffer = nil
elem.packet = nil
elem.keypair = nil
elem.endpoint = nil
}
/* Called when a new authenticated message has been received
*
* NOTE: Not thread safe, but called by sequential receiver!
*/
func (peer *Peer) keepKeyFreshReceiving() {
if peer.timers.sentLastMinuteHandshake.Get() {
return
}
keypair := peer.keypairs.Current()
if keypair != nil && keypair.isInitiator && time.Since(keypair.created) > (RejectAfterTime-KeepaliveTimeout-RekeyTimeout) {
peer.timers.sentLastMinuteHandshake.Set(true)
peer.SendHandshakeInitiation(false)
}
}
/* Receives incoming datagrams for the device
*
* Every time the bind is updated a new routine is started for
* IPv4 and IPv6 (separately)
*/
func (device *Device) RoutineReceiveIncoming(recv conn.ReceiveFunc) {
recvName := recv.PrettyName()
defer func() {
device.log.Verbosef("Routine: receive incoming %s - stopped", recvName)
device.queue.decryption.wg.Done()
device.queue.handshake.wg.Done()
device.net.stopping.Done()
}()
device.log.Verbosef("Routine: receive incoming %s - started", recvName)
// receive datagrams until conn is closed
buffer := device.GetMessageBuffer()
var (
err error
size int
endpoint conn.Endpoint
deathSpiral int
)
for {
size, endpoint, err = recv(buffer[:])
if err != nil {
device.PutMessageBuffer(buffer)
if errors.Is(err, net.ErrClosed) {
return
}
device.log.Verbosef("Failed to receive %s packet: %v", recvName, err)
if neterr, ok := err.(net.Error); ok && !neterr.Temporary() {
return
}
if deathSpiral < 10 {
deathSpiral++
time.Sleep(time.Second / 3)
buffer = device.GetMessageBuffer()
continue
}
return
}
deathSpiral = 0
if size < MinMessageSize {
continue
}
// check size of packet
packet := buffer[:size]
msgType := path.Usage(packet[0])
msgType_wg := msgType
if msgType >= path.MessageTransportType {
msgType_wg = path.MessageTransportType
}
var okay bool
switch msgType_wg {
// check if transport
case path.MessageTransportType:
// check size
if len(packet) < MessageTransportSize {
continue
}
// lookup key pair
receiver := binary.LittleEndian.Uint32(
packet[MessageTransportOffsetReceiver:MessageTransportOffsetCounter],
)
value := device.indexTable.Lookup(receiver)
keypair := value.keypair
if keypair == nil {
continue
}
// check keypair expiry
if keypair.created.Add(RejectAfterTime).Before(time.Now()) {
continue
}
// create work element
peer := value.peer
elem := device.GetInboundElement()
elem.Type = msgType
elem.packet = packet
elem.buffer = buffer
elem.keypair = keypair
elem.endpoint = endpoint
elem.counter = 0
elem.Mutex = sync.Mutex{}
elem.Lock()
// add to decryption queues
if peer.isRunning.Get() {
peer.queue.inbound.c <- elem
device.queue.decryption.c <- elem
buffer = device.GetMessageBuffer()
} else {
device.PutInboundElement(elem)
}
continue
// otherwise it is a fixed size & handshake related packet
case path.MessageInitiationType:
okay = len(packet) == MessageInitiationSize
case path.MessageResponseType:
okay = len(packet) == MessageResponseSize
case path.MessageCookieReplyType:
okay = len(packet) == MessageCookieReplySize
default:
device.log.Verbosef("Received message with unknown type")
}
if okay {
select {
case device.queue.handshake.c <- QueueHandshakeElement{
msgType: msgType,
buffer: buffer,
packet: packet,
endpoint: endpoint,
}:
buffer = device.GetMessageBuffer()
default:
}
}
}
}
func (device *Device) RoutineDecryption(id int) {
var nonce [chacha20poly1305.NonceSize]byte
defer device.log.Verbosef("Routine: decryption worker %d - stopped", id)
device.log.Verbosef("Routine: decryption worker %d - started", id)
for elem := range device.queue.decryption.c {
// split message into fields
counter := elem.packet[MessageTransportOffsetCounter:MessageTransportOffsetContent]
content := elem.packet[MessageTransportOffsetContent:]
// decrypt and release to consumer
var err error
elem.counter = binary.LittleEndian.Uint64(counter)
// copy counter to nonce
binary.LittleEndian.PutUint64(nonce[0x4:0xc], elem.counter)
elem.packet, err = elem.keypair.receive.Open(
content[:0],
nonce[:],
content,
nil,
)
if err != nil {
elem.packet = nil
}
elem.Unlock()
}
}
/* Handles incoming packets related to handshake
*/
func (device *Device) RoutineHandshake(id int) {
defer func() {
device.log.Verbosef("Routine: handshake worker %d - stopped", id)
device.queue.encryption.wg.Done()
}()
device.log.Verbosef("Routine: handshake worker %d - started", id)
for elem := range device.queue.handshake.c {
// handle cookie fields and ratelimiting
switch elem.msgType {
case path.MessageCookieReplyType:
// unmarshal packet
var reply MessageCookieReply
reader := bytes.NewReader(elem.packet)
err := binary.Read(reader, binary.LittleEndian, &reply)
if err != nil {
device.log.Verbosef("Failed to decode cookie reply")
goto skip
}
// lookup peer from index
entry := device.indexTable.Lookup(reply.Receiver)
if entry.peer == nil {
goto skip
}
// consume reply
if peer := entry.peer; peer.isRunning.Get() {
device.log.Verbosef("Receiving cookie response from %s", elem.endpoint.DstToString())
if !peer.cookieGenerator.ConsumeReply(&reply) {
device.log.Verbosef("Could not decrypt invalid cookie response")
}
}
goto skip
case path.MessageInitiationType, path.MessageResponseType:
// check mac fields and maybe ratelimit
if !device.cookieChecker.CheckMAC1(elem.packet) {
device.log.Verbosef("Received packet with invalid mac1")
goto skip
}
// endpoints destination address is the source of the datagram
if device.IsUnderLoad() {
// verify MAC2 field
if !device.cookieChecker.CheckMAC2(elem.packet, elem.endpoint.DstToBytes()) {
device.SendHandshakeCookie(&elem)
goto skip
}
// check ratelimiter
if !device.rate.limiter.Allow(elem.endpoint.DstIP()) {
goto skip
}
}
default:
device.log.Errorf("Invalid packet ended up in the handshake queue")
goto skip
}
// handle handshake initiation/response content
switch elem.msgType {
case path.MessageInitiationType:
// unmarshal
var msg MessageInitiation
reader := bytes.NewReader(elem.packet)
err := binary.Read(reader, binary.LittleEndian, &msg)
if err != nil {
device.log.Errorf("Failed to decode initiation message")
goto skip
}
// consume initiation
peer := device.ConsumeMessageInitiation(&msg)
if peer == nil {
device.log.Verbosef("Received invalid initiation message from %s", elem.endpoint.DstToString())
goto skip
}
// update timers
peer.timersAnyAuthenticatedPacketTraversal()
peer.timersAnyAuthenticatedPacketReceived()
// update endpoint
peer.SetEndpointFromPacket(elem.endpoint)
device.log.Verbosef("%v - Received handshake initiation", peer)
atomic.AddUint64(&peer.stats.rxBytes, uint64(len(elem.packet)))
peer.SendHandshakeResponse()
case path.MessageResponseType:
// unmarshal
var msg MessageResponse
reader := bytes.NewReader(elem.packet)
err := binary.Read(reader, binary.LittleEndian, &msg)
if err != nil {
device.log.Errorf("Failed to decode response message")
goto skip
}
// consume response
peer := device.ConsumeMessageResponse(&msg)
if peer == nil {
device.log.Verbosef("Received invalid response message from %s", elem.endpoint.DstToString())
goto skip
}
// update endpoint
peer.SetEndpointFromPacket(elem.endpoint)
device.log.Verbosef("%v - Received handshake response", peer)
atomic.AddUint64(&peer.stats.rxBytes, uint64(len(elem.packet)))
// update timers
peer.timersAnyAuthenticatedPacketTraversal()
peer.timersAnyAuthenticatedPacketReceived()
// derive keypair
err = peer.BeginSymmetricSession()
if err != nil {
device.log.Errorf("%v - Failed to derive keypair: %v", peer, err)
goto skip
}
peer.timersSessionDerived()
peer.timersHandshakeComplete()
peer.SendKeepalive()
}
skip:
device.PutMessageBuffer(elem.buffer)
}
}
func (peer *Peer) RoutineSequentialReceiver() {
device := peer.device
var peer_out *Peer
defer func() {
device.log.Verbosef("%v - Routine: sequential receiver - stopped", peer)
peer.stopping.Done()
}()
device.log.Verbosef("%v - Routine: sequential receiver - started", peer)
for elem := range peer.queue.inbound.c {
if elem == nil {
return
}
var EgHeader path.EgHeader
var err error
var src_nodeID mtypes.Vertex
var dst_nodeID mtypes.Vertex
var packet_type path.Usage
should_process := false
should_receive := false
should_transfer := false
currentTime := time.Now()
storeTime := currentTime.Add(time.Second)
if currentTime.After((*peer.LastPacketReceivedAdd1Sec.Load().(*time.Time))) {
peer.LastPacketReceivedAdd1Sec.Store(&storeTime)
}
elem.Lock()
if elem.packet == nil {
// decryption failed
goto skip
}
if !elem.keypair.replayFilter.ValidateCounter(elem.counter, RejectAfterMessages) {
goto skip
}
peer.SetEndpointFromPacket(elem.endpoint)
if peer.ReceivedWithKeypair(elem.keypair) {
peer.timersHandshakeComplete()
peer.SendStagedPackets()
}
peer.keepKeyFreshReceiving()
peer.timersAnyAuthenticatedPacketTraversal()
peer.timersAnyAuthenticatedPacketReceived()
atomic.AddUint64(&peer.stats.rxBytes, uint64(len(elem.packet)+MinMessageSize))
if len(elem.packet) == 0 {
device.log.Verbosef("%v - Receiving keepalive packet", peer)
goto skip
}
peer.timersDataReceived()
if len(elem.packet) <= path.EgHeaderLen {
device.log.Errorf("Invalid EgHeader from peer %v", peer)
goto skip
}
EgHeader, err = path.NewEgHeader(elem.packet[0:path.EgHeaderLen]) // EG header
src_nodeID = EgHeader.GetSrc()
dst_nodeID = EgHeader.GetDst()
elem.packet = elem.packet[:EgHeader.GetPacketLength()+path.EgHeaderLen] // EG header + true packet
packet_type = elem.Type
if device.IsSuperNode {
switch dst_nodeID {
case mtypes.ControlMessage:
should_process = true
case mtypes.SuperNodeMessage:
should_process = true
default:
device.log.Errorf("Invalid dst_nodeID received. Check your code for bug")
}
} else {
switch dst_nodeID {
case mtypes.Broadcast:
should_receive = true
should_transfer = true
case mtypes.SuperNodeMessage:
should_process = true
case mtypes.ControlMessage:
packet := elem.packet[path.EgHeaderLen:] //true packet
if device.CheckNoDup(packet) {
should_process = true
should_transfer = true
} else {
should_process = false
should_transfer = false
if device.LogLevel.LogTransit {
fmt.Printf("Transit: Duplicate packet received from %d through %d , src_nodeID = %d . Dropeed.\n", peer.ID, device.ID, src_nodeID)
}
}
case device.ID:
if packet_type == path.NormalPacket {
should_receive = true
} else {
should_process = true
}
default:
if device.graph.Next(device.ID, dst_nodeID) != nil {
should_transfer = true
} else {
device.log.Verbosef("No route to peer ID %v", dst_nodeID)
}
}
}
if should_transfer {
l2ttl := EgHeader.GetTTL()
if l2ttl == 0 {
device.log.Verbosef("TTL is 0 %v", dst_nodeID)
} else {
EgHeader.SetTTL(l2ttl - 1)
if dst_nodeID == mtypes.Broadcast { //Regular transfer algorithm
device.TransitBoardcastPacket(src_nodeID, peer.ID, elem.Type, elem.packet, MessageTransportOffsetContent)
} else if dst_nodeID == mtypes.ControlMessage { // Control Message will try send to every know node regardless the connectivity
skip_list := make(map[mtypes.Vertex]bool)
skip_list[src_nodeID] = true //Don't send to conimg peer and source peer
skip_list[peer.ID] = true
device.SpreadPacket(skip_list, elem.Type, elem.packet, MessageTransportOffsetContent)
} else {
next_id := device.graph.Next(device.ID, dst_nodeID)
if next_id != nil {
device.peers.RLock()
peer_out = device.peers.IDMap[*next_id]
device.peers.RUnlock()
if device.LogLevel.LogTransit {
fmt.Printf("Transit: Transfer packet from %d through %d to %d\n", peer.ID, device.ID, peer_out.ID)
}
device.SendPacket(peer_out, elem.Type, elem.packet, MessageTransportOffsetContent)
}
}
}
}
if should_process {
if packet_type != path.NormalPacket {
if device.LogLevel.LogControl {
if peer.GetEndpointDstStr() != "" {
fmt.Println("Control: Received From:" + peer.GetEndpointDstStr() + " " + device.sprint_received(packet_type, elem.packet[path.EgHeaderLen:]))
}
}
err = device.process_received(packet_type, peer, elem.packet[path.EgHeaderLen:])
if err != nil {
device.log.Errorf(err.Error())
}
}
}
if should_receive { // Write message to tap device
if packet_type == path.NormalPacket {
if len(elem.packet) <= path.EgHeaderLen+12 {
device.log.Errorf("Invalid normal packet: Ethernet packet too small from peer %v", peer.ID.ToString())
goto skip
}
if device.LogLevel.LogNormal {
packet_len := len(elem.packet) - path.EgHeaderLen
fmt.Println("Normal: Reveived Normal packet From:" + peer.GetEndpointDstStr() + " SrcID:" + src_nodeID.ToString() + " DstID:" + dst_nodeID.ToString() + " Len:" + strconv.Itoa(packet_len))
packet := gopacket.NewPacket(elem.packet[path.EgHeaderLen:], layers.LayerTypeEthernet, gopacket.Default)
fmt.Println(packet.Dump())
}
src_macaddr := tap.GetSrcMacAddr(elem.packet[path.EgHeaderLen:])
if !tap.IsNotUnicast(src_macaddr) {
val, ok := device.l2fib.Load(src_macaddr)
if ok {
idtime := val.(*IdAndTime)
if idtime.ID != src_nodeID {
idtime.ID = src_nodeID
if device.LogLevel.LogInternal {
fmt.Printf("Internal: L2FIB [%v -> %v] updated.\n", src_macaddr.String(), src_nodeID)
}
}
idtime.Time = time.Now()
} else {
device.l2fib.Store(src_macaddr, &IdAndTime{
ID: src_nodeID,
Time: time.Now(),
}) // Write to l2fib table
if device.LogLevel.LogInternal {
fmt.Printf("Internal: L2FIB [%v -> %v] added.\n", src_macaddr.String(), src_nodeID)
}
}
}
_, err = device.tap.device.Write(elem.buffer[:MessageTransportOffsetContent+len(elem.packet)], MessageTransportOffsetContent+path.EgHeaderLen)
if err != nil && !device.isClosed() {
device.log.Errorf("Failed to write packet to TUN device: %v", err)
}
if len(peer.queue.inbound.c) == 0 {
err = device.tap.device.Flush()
if err != nil {
peer.device.log.Errorf("Unable to flush packets: %v", err)
}
}
}
}
skip:
device.PutMessageBuffer(elem.buffer)
device.PutInboundElement(elem)
}
}