/
proxy.go
359 lines (309 loc) · 8.43 KB
/
proxy.go
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package quicproxy
import (
"net"
"sort"
"sync"
"time"
"github.com/lucas-clemente/quic-go/internal/protocol"
"github.com/lucas-clemente/quic-go/internal/utils"
)
// Connection is a UDP connection
type connection struct {
ClientAddr *net.UDPAddr // Address of the client
ServerConn *net.UDPConn // UDP connection to server
incomingPackets chan packetEntry
Incoming *queue
Outgoing *queue
}
func (c *connection) queuePacket(t time.Time, b []byte) {
c.incomingPackets <- packetEntry{Time: t, Raw: b}
}
// Direction is the direction a packet is sent.
type Direction int
const (
// DirectionIncoming is the direction from the client to the server.
DirectionIncoming Direction = iota
// DirectionOutgoing is the direction from the server to the client.
DirectionOutgoing
// DirectionBoth is both incoming and outgoing
DirectionBoth
)
type packetEntry struct {
Time time.Time
Raw []byte
}
type packetEntries []packetEntry
func (e packetEntries) Len() int { return len(e) }
func (e packetEntries) Less(i, j int) bool { return e[i].Time.Before(e[j].Time) }
func (e packetEntries) Swap(i, j int) { e[i], e[j] = e[j], e[i] }
type queue struct {
sync.Mutex
timer *utils.Timer
Packets packetEntries
}
func newQueue() *queue {
return &queue{timer: utils.NewTimer()}
}
func (q *queue) Add(e packetEntry) {
q.Lock()
q.Packets = append(q.Packets, e)
if len(q.Packets) > 1 {
lastIndex := len(q.Packets) - 1
if q.Packets[lastIndex].Time.Before(q.Packets[lastIndex-1].Time) {
sort.Stable(q.Packets)
}
}
q.timer.Reset(q.Packets[0].Time)
q.Unlock()
}
func (q *queue) Get() []byte {
q.Lock()
raw := q.Packets[0].Raw
q.Packets = q.Packets[1:]
if len(q.Packets) > 0 {
q.timer.Reset(q.Packets[0].Time)
}
q.Unlock()
return raw
}
func (q *queue) Timer() <-chan time.Time { return q.timer.Chan() }
func (q *queue) SetTimerRead() { q.timer.SetRead() }
func (q *queue) Close() { q.timer.Stop() }
func (d Direction) String() string {
switch d {
case DirectionIncoming:
return "Incoming"
case DirectionOutgoing:
return "Outgoing"
case DirectionBoth:
return "both"
default:
panic("unknown direction")
}
}
// Is says if one direction matches another direction.
// For example, incoming matches both incoming and both, but not outgoing.
func (d Direction) Is(dir Direction) bool {
if d == DirectionBoth || dir == DirectionBoth {
return true
}
return d == dir
}
// DropCallback is a callback that determines which packet gets dropped.
type DropCallback func(dir Direction, packet []byte) bool
// NoDropper doesn't drop packets.
var NoDropper DropCallback = func(Direction, []byte) bool {
return false
}
// DelayCallback is a callback that determines how much delay to apply to a packet.
type DelayCallback func(dir Direction, packet []byte) time.Duration
// NoDelay doesn't apply a delay.
var NoDelay DelayCallback = func(Direction, []byte) time.Duration {
return 0
}
// Opts are proxy options.
type Opts struct {
// The address this proxy proxies packets to.
RemoteAddr string
// DropPacket determines whether a packet gets dropped.
DropPacket DropCallback
// DelayPacket determines how long a packet gets delayed. This allows
// simulating a connection with non-zero RTTs.
// Note that the RTT is the sum of the delay for the incoming and the outgoing packet.
DelayPacket DelayCallback
}
// QuicProxy is a QUIC proxy that can drop and delay packets.
type QuicProxy struct {
mutex sync.Mutex
closeChan chan struct{}
conn *net.UDPConn
serverAddr *net.UDPAddr
dropPacket DropCallback
delayPacket DelayCallback
// Mapping from client addresses (as host:port) to connection
clientDict map[string]*connection
logger utils.Logger
}
// NewQuicProxy creates a new UDP proxy
func NewQuicProxy(local string, opts *Opts) (*QuicProxy, error) {
if opts == nil {
opts = &Opts{}
}
laddr, err := net.ResolveUDPAddr("udp", local)
if err != nil {
return nil, err
}
conn, err := net.ListenUDP("udp", laddr)
if err != nil {
return nil, err
}
raddr, err := net.ResolveUDPAddr("udp", opts.RemoteAddr)
if err != nil {
return nil, err
}
packetDropper := NoDropper
if opts.DropPacket != nil {
packetDropper = opts.DropPacket
}
packetDelayer := NoDelay
if opts.DelayPacket != nil {
packetDelayer = opts.DelayPacket
}
p := QuicProxy{
clientDict: make(map[string]*connection),
conn: conn,
closeChan: make(chan struct{}),
serverAddr: raddr,
dropPacket: packetDropper,
delayPacket: packetDelayer,
logger: utils.DefaultLogger.WithPrefix("proxy"),
}
p.logger.Debugf("Starting UDP Proxy %s <-> %s", conn.LocalAddr(), raddr)
go p.runProxy()
return &p, nil
}
// Close stops the UDP Proxy
func (p *QuicProxy) Close() error {
p.mutex.Lock()
defer p.mutex.Unlock()
close(p.closeChan)
for _, c := range p.clientDict {
if err := c.ServerConn.Close(); err != nil {
return err
}
c.Incoming.Close()
c.Outgoing.Close()
}
return p.conn.Close()
}
// LocalAddr is the address the proxy is listening on.
func (p *QuicProxy) LocalAddr() net.Addr {
return p.conn.LocalAddr()
}
// LocalPort is the UDP port number the proxy is listening on.
func (p *QuicProxy) LocalPort() int {
return p.conn.LocalAddr().(*net.UDPAddr).Port
}
func (p *QuicProxy) newConnection(cliAddr *net.UDPAddr) (*connection, error) {
srvudp, err := net.DialUDP("udp", nil, p.serverAddr)
if err != nil {
return nil, err
}
return &connection{
ClientAddr: cliAddr,
ServerConn: srvudp,
incomingPackets: make(chan packetEntry, 10),
Incoming: newQueue(),
Outgoing: newQueue(),
}, nil
}
// runProxy listens on the proxy address and handles incoming packets.
func (p *QuicProxy) runProxy() error {
for {
buffer := make([]byte, protocol.MaxPacketBufferSize)
n, cliaddr, err := p.conn.ReadFromUDP(buffer)
if err != nil {
return err
}
raw := buffer[0:n]
saddr := cliaddr.String()
p.mutex.Lock()
conn, ok := p.clientDict[saddr]
if !ok {
conn, err = p.newConnection(cliaddr)
if err != nil {
p.mutex.Unlock()
return err
}
p.clientDict[saddr] = conn
go p.runIncomingConnection(conn)
go p.runOutgoingConnection(conn)
}
p.mutex.Unlock()
if p.dropPacket(DirectionIncoming, raw) {
if p.logger.Debug() {
p.logger.Debugf("dropping incoming packet(%d bytes)", n)
}
continue
}
delay := p.delayPacket(DirectionIncoming, raw)
if delay == 0 {
if p.logger.Debug() {
p.logger.Debugf("forwarding incoming packet (%d bytes) to %s", len(raw), conn.ServerConn.RemoteAddr())
}
if _, err := conn.ServerConn.Write(raw); err != nil {
return err
}
} else {
now := time.Now()
if p.logger.Debug() {
p.logger.Debugf("delaying incoming packet (%d bytes) to %s by %s", len(raw), conn.ServerConn.RemoteAddr(), delay)
}
conn.queuePacket(now.Add(delay), raw)
}
}
}
// runConnection handles packets from server to a single client
func (p *QuicProxy) runOutgoingConnection(conn *connection) error {
outgoingPackets := make(chan packetEntry, 10)
go func() {
for {
buffer := make([]byte, protocol.MaxPacketBufferSize)
n, err := conn.ServerConn.Read(buffer)
if err != nil {
return
}
raw := buffer[0:n]
if p.dropPacket(DirectionOutgoing, raw) {
if p.logger.Debug() {
p.logger.Debugf("dropping outgoing packet(%d bytes)", n)
}
continue
}
delay := p.delayPacket(DirectionOutgoing, raw)
if delay == 0 {
if p.logger.Debug() {
p.logger.Debugf("forwarding outgoing packet (%d bytes) to %s", len(raw), conn.ClientAddr)
}
if _, err := p.conn.WriteToUDP(raw, conn.ClientAddr); err != nil {
return
}
} else {
now := time.Now()
if p.logger.Debug() {
p.logger.Debugf("delaying outgoing packet (%d bytes) to %s by %s", len(raw), conn.ClientAddr, delay)
}
outgoingPackets <- packetEntry{Time: now.Add(delay), Raw: raw}
}
}
}()
for {
select {
case <-p.closeChan:
return nil
case e := <-outgoingPackets:
conn.Outgoing.Add(e)
case <-conn.Outgoing.Timer():
conn.Outgoing.SetTimerRead()
if _, err := p.conn.WriteTo(conn.Outgoing.Get(), conn.ClientAddr); err != nil {
return err
}
}
}
}
func (p *QuicProxy) runIncomingConnection(conn *connection) error {
for {
select {
case <-p.closeChan:
return nil
case e := <-conn.incomingPackets:
// Send the packet to the server
conn.Incoming.Add(e)
case <-conn.Incoming.Timer():
conn.Incoming.SetTimerRead()
if _, err := conn.ServerConn.Write(conn.Incoming.Get()); err != nil {
return err
}
}
}
}