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Merge pull request #491 from Arceliar/flowkey

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Fix the old flowkey stuff so congestion control actually works...
This commit is contained in:
Neil Alexander 2019-08-07 10:33:17 +01:00 committed by GitHub
commit c99ed9fb60
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5 changed files with 105 additions and 52 deletions
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7
src/tuntap/conn.go
View File

@ -96,8 +96,11 @@ func (s *tunConn) writer() error {
if !ok {
return errors.New("send closed")
}
// TODO write timeout and close
if err := s.conn.WriteNoCopy(bs); err != nil {
msg := yggdrasil.FlowKeyMessage{
FlowKey: util.GetFlowKey(bs),
Message: bs,
}
if err := s.conn.WriteNoCopy(msg); err != nil {
if e, eok := err.(yggdrasil.ConnError); !eok {
if e.Closed() {
s.tun.log.Debugln(s.conn.String(), "TUN/TAP generic write debug:", err)

38
src/util/util.go
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@ -106,3 +106,41 @@ func DecodeCoordString(in string) (out []uint64) {
}
return out
}
// GetFlowLabel takes an IP packet as an argument and returns some information about the traffic flow.
// For IPv4 packets, this is derived from the source and destination protocol and port numbers.
// For IPv6 packets, this is derived from the FlowLabel field of the packet if this was set, otherwise it's handled like IPv4.
// The FlowKey is then used internally by Yggdrasil for congestion control.
func GetFlowKey(bs []byte) uint64 {
// Work out the flowkey - this is used to determine which switch queue
// traffic will be pushed to in the event of congestion
var flowkey uint64
// Get the IP protocol version from the packet
switch bs[0] & 0xf0 {
case 0x40: // IPv4 packet
// Check the packet meets minimum UDP packet length
if len(bs) >= 24 {
// Is the protocol TCP, UDP or SCTP?
if bs[9] == 0x06 || bs[9] == 0x11 || bs[9] == 0x84 {
ihl := bs[0] & 0x0f * 4 // Header length
flowkey = uint64(bs[9])<<32 /* proto */ |
uint64(bs[ihl+0])<<24 | uint64(bs[ihl+1])<<16 /* sport */ |
uint64(bs[ihl+2])<<8 | uint64(bs[ihl+3]) /* dport */
}
}
case 0x60: // IPv6 packet
// Check if the flowlabel was specified in the packet header
flowkey = uint64(bs[1]&0x0f)<<16 | uint64(bs[2])<<8 | uint64(bs[3])
// If the flowlabel isn't present, make protokey from proto | sport | dport
// if the packet meets minimum UDP packet length
if flowkey == 0 && len(bs) >= 48 {
// Is the protocol TCP, UDP or SCTP?
if bs[6] == 0x06 || bs[6] == 0x11 || bs[6] == 0x84 {
flowkey = uint64(bs[6])<<32 /* proto */ |
uint64(bs[40])<<24 | uint64(bs[41])<<16 /* sport */ |
uint64(bs[42])<<8 | uint64(bs[43]) /* dport */
}
}
}
return flowkey
}

12
src/yggdrasil/conn.go
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@ -183,11 +183,11 @@ func (c *Conn) Read(b []byte) (int, error) {
}
// Used internally by Write, the caller must not reuse the argument bytes when no error occurs
func (c *Conn) WriteNoCopy(bs []byte) error {
func (c *Conn) WriteNoCopy(msg FlowKeyMessage) error {
var err error
sessionFunc := func() {
// Does the packet exceed the permitted size for the session?
if uint16(len(bs)) > c.session.getMTU() {
if uint16(len(msg.Message)) > c.session.getMTU() {
err = ConnError{errors.New("packet too big"), true, false, false, int(c.session.getMTU())}
return
}
@ -216,7 +216,7 @@ func (c *Conn) WriteNoCopy(bs []byte) error {
} else {
err = ConnError{errors.New("session closed"), false, false, true, 0}
}
case c.session.send <- bs:
case c.session.send <- msg:
}
}
return err
@ -225,10 +225,10 @@ func (c *Conn) WriteNoCopy(bs []byte) error {
// Implements net.Conn.Write
func (c *Conn) Write(b []byte) (int, error) {
written := len(b)
bs := append(util.GetBytes(), b...)
err := c.WriteNoCopy(bs)
msg := FlowKeyMessage{Message: append(util.GetBytes(), b...)}
err := c.WriteNoCopy(msg)
if err != nil {
util.PutBytes(bs)
util.PutBytes(msg.Message)
written = 0
}
return written, err

2
src/yggdrasil/router.go
View File

@ -166,7 +166,7 @@ func (r *router) handleTraffic(packet []byte) {
return
}
select {
case sinfo.fromRouter <- &p:
case sinfo.fromRouter <- p:
case <-sinfo.cancel.Finished():
util.PutBytes(p.Payload)
}

98
src/yggdrasil/session.go
View File

@ -18,39 +18,39 @@ import (
// All the information we know about an active session.
// This includes coords, permanent and ephemeral keys, handles and nonces, various sorts of timing information for timeout and maintenance, and some metadata for the admin API.
type sessionInfo struct {
mutex sync.Mutex // Protects all of the below, use it any time you read/chance the contents of a session
core *Core //
reconfigure chan chan error //
theirAddr address.Address //
theirSubnet address.Subnet //
theirPermPub crypto.BoxPubKey //
theirSesPub crypto.BoxPubKey //
mySesPub crypto.BoxPubKey //
mySesPriv crypto.BoxPrivKey //
sharedSesKey crypto.BoxSharedKey // derived from session keys
theirHandle crypto.Handle //
myHandle crypto.Handle //
theirNonce crypto.BoxNonce //
theirNonceMask uint64 //
myNonce crypto.BoxNonce //
theirMTU uint16 //
myMTU uint16 //
wasMTUFixed bool // Was the MTU fixed by a receive error?
timeOpened time.Time // Time the sessino was opened
time time.Time // Time we last received a packet
mtuTime time.Time // time myMTU was last changed
pingTime time.Time // time the first ping was sent since the last received packet
pingSend time.Time // time the last ping was sent
coords []byte // coords of destination
reset bool // reset if coords change
tstamp int64 // ATOMIC - tstamp from their last session ping, replay attack mitigation
bytesSent uint64 // Bytes of real traffic sent in this session
bytesRecvd uint64 // Bytes of real traffic received in this session
fromRouter chan *wire_trafficPacket // Received packets go here, picked up by the associated Conn
init chan struct{} // Closed when the first session pong arrives, used to signal that the session is ready for initial use
cancel util.Cancellation // Used to terminate workers
recv chan []byte
send chan []byte
mutex sync.Mutex // Protects all of the below, use it any time you read/chance the contents of a session
core *Core //
reconfigure chan chan error //
theirAddr address.Address //
theirSubnet address.Subnet //
theirPermPub crypto.BoxPubKey //
theirSesPub crypto.BoxPubKey //
mySesPub crypto.BoxPubKey //
mySesPriv crypto.BoxPrivKey //
sharedSesKey crypto.BoxSharedKey // derived from session keys
theirHandle crypto.Handle //
myHandle crypto.Handle //
theirNonce crypto.BoxNonce //
theirNonceMask uint64 //
myNonce crypto.BoxNonce //
theirMTU uint16 //
myMTU uint16 //
wasMTUFixed bool // Was the MTU fixed by a receive error?
timeOpened time.Time // Time the sessino was opened
time time.Time // Time we last received a packet
mtuTime time.Time // time myMTU was last changed
pingTime time.Time // time the first ping was sent since the last received packet
pingSend time.Time // time the last ping was sent
coords []byte // coords of destination
reset bool // reset if coords change
tstamp int64 // ATOMIC - tstamp from their last session ping, replay attack mitigation
bytesSent uint64 // Bytes of real traffic sent in this session
bytesRecvd uint64 // Bytes of real traffic received in this session
init chan struct{} // Closed when the first session pong arrives, used to signal that the session is ready for initial use
cancel util.Cancellation // Used to terminate workers
fromRouter chan wire_trafficPacket // Received packets go here, to be decrypted by the session
recv chan []byte // Decrypted packets go here, picked up by the associated Conn
send chan FlowKeyMessage // Packets with optional flow key go here, to be encrypted and sent
}
func (sinfo *sessionInfo) doFunc(f func()) {
@ -228,9 +228,9 @@ func (ss *sessions) createSession(theirPermKey *crypto.BoxPubKey) *sessionInfo {
sinfo.myHandle = *crypto.NewHandle()
sinfo.theirAddr = *address.AddrForNodeID(crypto.GetNodeID(&sinfo.theirPermPub))
sinfo.theirSubnet = *address.SubnetForNodeID(crypto.GetNodeID(&sinfo.theirPermPub))
sinfo.fromRouter = make(chan *wire_trafficPacket, 1)
sinfo.fromRouter = make(chan wire_trafficPacket, 1)
sinfo.recv = make(chan []byte, 32)
sinfo.send = make(chan []byte, 32)
sinfo.send = make(chan FlowKeyMessage, 32)
ss.sinfos[sinfo.myHandle] = &sinfo
ss.byTheirPerm[sinfo.theirPermPub] = &sinfo.myHandle
go func() {
@ -442,13 +442,18 @@ func (sinfo *sessionInfo) startWorkers() {
go sinfo.sendWorker()
}
type FlowKeyMessage struct {
FlowKey uint64
Message []byte
}
func (sinfo *sessionInfo) recvWorker() {
// TODO move theirNonce etc into a struct that gets stored here, passed in over a channel
// Since there's no reason for anywhere else in the session code to need to *read* it...
// Only needs to be updated from the outside if a ping resets it...
// That would get rid of the need to take a mutex for the sessionFunc
var callbacks []chan func()
doRecv := func(p *wire_trafficPacket) {
doRecv := func(p wire_trafficPacket) {
var bs []byte
var err error
var k crypto.BoxSharedKey
@ -524,16 +529,22 @@ func (sinfo *sessionInfo) sendWorker() {
// TODO move info that this worker needs here, send updates via a channel
// Otherwise we need to take a mutex to avoid races with update()
var callbacks []chan func()
doSend := func(bs []byte) {
doSend := func(msg FlowKeyMessage) {
var p wire_trafficPacket
var k crypto.BoxSharedKey
sessionFunc := func() {
sinfo.bytesSent += uint64(len(bs))
sinfo.bytesSent += uint64(len(msg.Message))
p = wire_trafficPacket{
Coords: append([]byte(nil), sinfo.coords...),
Handle: sinfo.theirHandle,
Nonce: sinfo.myNonce,
}
if msg.FlowKey != 0 {
// Helps ensure that traffic from this flow ends up in a separate queue from other flows
// The zero padding relies on the fact that the self-peer is always on port 0
p.Coords = append(p.Coords, 0)
p.Coords = wire_put_uint64(msg.FlowKey, p.Coords)
}
sinfo.myNonce.Increment()
k = sinfo.sharedSesKey
}
@ -542,12 +553,13 @@ func (sinfo *sessionInfo) sendWorker() {
ch := make(chan func(), 1)
poolFunc := func() {
// Encrypt the packet
p.Payload, _ = crypto.BoxSeal(&k, bs, &p.Nonce)
packet := p.encode()
p.Payload, _ = crypto.BoxSeal(&k, msg.Message, &p.Nonce)
// The callback will send the packet
callback := func() {
// Encoding may block on a util.GetBytes(), so kept out of the worker pool
packet := p.encode()
// Cleanup
util.PutBytes(bs)
util.PutBytes(msg.Message)
util.PutBytes(p.Payload)
// Send the packet
sinfo.core.router.out(packet)
@ -566,8 +578,8 @@ func (sinfo *sessionInfo) sendWorker() {
f()
case <-sinfo.cancel.Finished():
return
case bs := <-sinfo.send:
doSend(bs)
case msg := <-sinfo.send:
doSend(msg)
}
}
select {