dissertation-2-code/udp/listener.go
Jake Hillion 898496fe94
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2021-05-13 22:48:47 +01:00

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2.2 KiB
Go

package udp
import (
"context"
"log"
"mpbl3p/proxy"
"net"
"time"
)
type ComparableUdpAddress struct {
IP [16]byte
Port int
Zone string
}
func fromUdpAddress(address net.UDPAddr) ComparableUdpAddress {
var ip [16]byte
copy(ip[:], address.IP)
return ComparableUdpAddress{
IP: ip,
Port: address.Port,
Zone: address.Zone,
}
}
func NewListener(
ctx context.Context,
p *proxy.Proxy,
local string,
vs []func() proxy.MacVerifier,
gs []func() proxy.MacGenerator,
c func() Congestion,
enableConsumers bool,
enableProducers bool,
) error {
laddr, err := net.ResolveUDPAddr("udp", local)
if err != nil {
return err
}
pconn, err := net.ListenUDP("udp", laddr)
if err != nil {
return err
}
receivedConnections := make(map[ComparableUdpAddress]*InboundFlow)
go func() {
for ctx.Err() == nil {
buf := make([]byte, 6000)
if err := pconn.SetReadDeadline(time.Now().Add(time.Second)); err != nil {
panic(err)
}
n, addr, err := pconn.ReadFromUDP(buf)
if err != nil {
if e, ok := err.(net.Error); ok && e.Timeout() {
continue
}
panic(err)
}
raddr := fromUdpAddress(*addr)
if fi, exists := receivedConnections[raddr]; exists {
log.Println("existing flow. queuing...")
if err := fi.queueDatagram(ctx, buf[:n]); err != nil {
log.Println("error")
continue
}
log.Println("queued")
continue
}
var verifiers = make([]proxy.MacVerifier, len(vs))
for i, v := range vs {
verifiers[i] = v()
}
var generators = make([]proxy.MacGenerator, len(gs))
for i, g := range gs {
generators[i] = g()
}
f := newFlow(c(), verifiers, generators)
f.writer = pconn
f.raddr = addr
f.isAlive = true
fi, err := newInboundFlow(f)
if err != nil {
log.Println(err)
continue
}
log.Printf("received new udp connection: %v\n", f)
go fi.processPackets(ctx)
go fi.earlyUpdateLoop(ctx, 0)
receivedConnections[raddr] = fi
if enableConsumers {
p.AddConsumer(ctx, fi)
}
if enableProducers {
p.AddProducer(ctx, fi)
}
log.Println("handling...")
if err := fi.queueDatagram(ctx, buf[:n]); err != nil {
return
}
log.Println("handled")
}
}()
return nil
}