318 lines
7.8 KiB
Go
318 lines
7.8 KiB
Go
/*
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Copyright 2024 Josh Deprez
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package main
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import (
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"context"
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"errors"
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"flag"
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"io"
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"log"
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"math/rand/v2"
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"net"
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"os"
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"os/signal"
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"regexp"
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"sync"
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"time"
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"gitea.drjosh.dev/josh/jrouter/atalk"
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"gitea.drjosh.dev/josh/jrouter/aurp"
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"github.com/google/gopacket/pcap"
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"github.com/sfiera/multitalk/pkg/ddp"
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"github.com/sfiera/multitalk/pkg/ethernet"
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"github.com/sfiera/multitalk/pkg/ethertalk"
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)
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var hasPortRE = regexp.MustCompile(`:\d+$`)
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var configFilePath = flag.String("config", "jrouter.yaml", "Path to configuration file to use")
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func main() {
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flag.Parse()
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log.Println("jrouter")
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cfg, err := loadConfig(*configFilePath)
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if err != nil {
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log.Fatalf("Couldn't load configuration file: %v", err)
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}
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localIP := net.ParseIP(cfg.LocalIP).To4()
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if localIP == nil {
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iaddrs, err := net.InterfaceAddrs()
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if err != nil {
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log.Fatalf("Couldn't read network interface addresses: %v", err)
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}
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for _, iaddr := range iaddrs {
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inet, ok := iaddr.(*net.IPNet)
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if !ok {
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continue
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}
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if !inet.IP.IsGlobalUnicast() {
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continue
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}
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localIP = inet.IP.To4()
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if localIP != nil {
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break
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}
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}
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if localIP == nil {
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log.Fatalf("No global unicast IPv4 addresses on any network interfaces, and no valid local_ip address in configuration")
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}
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}
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localDI := aurp.IPDomainIdentifier(localIP)
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log.Printf("Using %v as local domain identifier", localIP)
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log.Printf("EtherTalk configuration: %+v", cfg.EtherTalk)
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peers := make(map[udpAddr]*peer)
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var nextConnID uint16
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for nextConnID == 0 {
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nextConnID = uint16(rand.IntN(0x10000))
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}
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ln, err := net.ListenUDP("udp4", &net.UDPAddr{Port: int(cfg.ListenPort)})
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if err != nil {
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log.Fatalf("Couldn't listen on udp4:387: %v", err)
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}
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log.Printf("Listening on %v", ln.LocalAddr())
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log.Println("Press ^C or send SIGINT to stop the router gracefully")
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cctx, cancel := context.WithCancel(context.Background())
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defer cancel()
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ctx, _ := signal.NotifyContext(cctx, os.Interrupt)
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// Open PCAP session
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iface, err := net.InterfaceByName(cfg.EtherTalk.Device)
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if err != nil {
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log.Fatalf("Couldn't find interface named %q: %v", cfg.EtherTalk.Device, err)
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}
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myHWAddr := ethernet.Addr(iface.HardwareAddr)
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pcapHandle, err := atalk.StartPcap(cfg.EtherTalk.Device)
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if err != nil {
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log.Fatalf("Couldn't open network device for AppleTalk: %v", err)
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}
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defer pcapHandle.Close()
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// Wait until all peer handlers have finished before closing the port
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var handlersWG sync.WaitGroup
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defer func() {
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log.Print("Waiting for handlers to return...")
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handlersWG.Wait()
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ln.Close()
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}()
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goPeerHandler := func(p *peer) {
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handlersWG.Add(1)
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go func() {
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defer handlersWG.Done()
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p.handle(ctx)
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}()
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}
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// --------------- Configured peer setup ---------------
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for _, peerStr := range cfg.Peers {
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if !hasPortRE.MatchString(peerStr) {
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peerStr += ":387"
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}
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raddr, err := net.ResolveUDPAddr("udp4", peerStr)
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if err != nil {
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log.Fatalf("Invalid UDP address: %v", err)
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}
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log.Printf("resolved %q to %v", peerStr, raddr)
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peer := &peer{
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cfg: cfg,
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tr: &aurp.Transport{
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LocalDI: localDI,
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RemoteDI: aurp.IPDomainIdentifier(raddr.IP),
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LocalConnID: nextConnID,
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},
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conn: ln,
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raddr: raddr,
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recv: make(chan aurp.Packet, 1024),
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}
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aurp.Inc(&nextConnID)
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peers[udpAddrFromNet(raddr)] = peer
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goPeerHandler(peer)
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}
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// -------------------- AARP --------------------
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aarpMachine := NewAARPMachine(cfg, pcapHandle, myHWAddr)
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aarpCh := make(chan *ethertalk.Packet, 1024)
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go aarpMachine.Run(ctx, aarpCh)
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// -------------------- RTMP --------------------
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rtmpMachine := &RTMPMachine{
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aarp: aarpMachine,
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cfg: cfg,
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pcapHandle: pcapHandle,
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}
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go rtmpMachine.Run(ctx)
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// ---------- Raw AppleTalk/AARP inbound ----------
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go func() {
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for {
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if ctx.Err() != nil {
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return
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}
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rawPkt, _, err := pcapHandle.ReadPacketData()
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if errors.Is(err, pcap.NextErrorTimeoutExpired) {
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continue
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}
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if errors.Is(err, io.EOF) || errors.Is(err, pcap.NextErrorNoMorePackets) {
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return
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}
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if err != nil {
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log.Printf("Couldn't read AppleTalk / AARP packet data: %v", err)
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return
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}
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ethFrame := new(ethertalk.Packet)
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if err := ethertalk.Unmarshal(rawPkt, ethFrame); err != nil {
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log.Printf("Couldn't unmarshal EtherTalk frame: %v", err)
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continue
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}
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// Ignore if sent by me
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if ethFrame.Src == myHWAddr {
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continue
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}
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switch ethFrame.SNAPProto {
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case ethertalk.AARPProto:
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log.Print("Got an AARP frame")
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aarpCh <- ethFrame
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case ethertalk.AppleTalkProto:
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log.Print("Got an AppleTalk frame")
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var ddpkt ddp.ExtPacket
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if err := ddp.ExtUnmarshal(ethFrame.Payload, &ddpkt); err != nil {
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log.Printf("Couldn't unmarshal DDP packet: %v", err)
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continue
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}
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log.Printf("DDP: src (%d.%d s %d) dst (%d.%d s %d) proto %d data len %d",
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ddpkt.SrcNet, ddpkt.SrcNode, ddpkt.SrcSocket,
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ddpkt.DstNet, ddpkt.DstNode, ddpkt.DstSocket,
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ddpkt.Proto, len(ddpkt.Data))
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// Glean address info for AMT
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srcAddr := ddp.Addr{Network: ddpkt.SrcNet, Node: ddpkt.SrcNode}
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aarpMachine.Learn(srcAddr, ethFrame.Src)
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log.Printf("DDP: Gleaned that %v -> %v", srcAddr, ethFrame.Src)
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default:
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log.Printf("Read unknown packet %s -> %s with payload %x", ethFrame.Src, ethFrame.Dst, ethFrame.Payload)
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}
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}
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}()
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// ---------- AURP inbound ----------
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for {
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if ctx.Err() != nil {
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return
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}
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ln.SetReadDeadline(time.Now().Add(100 * time.Millisecond))
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pktbuf := make([]byte, 4096)
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pktlen, raddr, readErr := ln.ReadFromUDP(pktbuf)
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var operr *net.OpError
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if errors.As(readErr, &operr) && operr.Timeout() {
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continue
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}
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log.Printf("AURP: Received packet of length %d from %v", pktlen, raddr)
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dh, pkt, parseErr := aurp.ParsePacket(pktbuf[:pktlen])
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if parseErr != nil {
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log.Printf("AURP: Failed to parse packet: %v", parseErr)
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}
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if readErr != nil {
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log.Printf("AURP: Failed to read packet: %v", readErr)
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return
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}
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log.Printf("AURP: The packet parsed succesfully as a %T", pkt)
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if apkt, ok := pkt.(*aurp.AppleTalkPacket); ok {
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var ddpkt ddp.ExtPacket
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if err := ddp.ExtUnmarshal(apkt.Data, &ddpkt); err != nil {
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log.Printf("AURP: Couldn't unmarshal encapsulated DDP packet: %v", err)
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continue
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}
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log.Printf("AURP encapsulated DDP: src (%d.%d s %d) dst (%d.%d s %d) proto %d data len %d",
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ddpkt.SrcNet, ddpkt.SrcNode, ddpkt.SrcSocket,
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ddpkt.DstNet, ddpkt.DstNode, ddpkt.DstSocket,
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ddpkt.Proto, len(ddpkt.Data))
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continue
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}
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// Existing peer?
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ra := udpAddrFromNet(raddr)
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pr := peers[ra]
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if pr == nil {
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// New peer!
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pr = &peer{
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cfg: cfg,
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tr: &aurp.Transport{
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LocalDI: localDI,
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RemoteDI: dh.SourceDI, // platinum rule
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LocalConnID: nextConnID,
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},
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conn: ln,
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raddr: raddr,
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recv: make(chan aurp.Packet, 1024),
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}
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aurp.Inc(&nextConnID)
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peers[ra] = pr
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goPeerHandler(pr)
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}
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// Pass the packet to the goroutine in charge of this peer.
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select {
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case pr.recv <- pkt:
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// That's it for us.
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case <-ctx.Done():
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return
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}
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}
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}
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// Hashable net.UDPAddr
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type udpAddr struct {
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ipv4 [4]byte
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port uint16
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}
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func udpAddrFromNet(a *net.UDPAddr) udpAddr {
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return udpAddr{
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ipv4: [4]byte(a.IP.To4()),
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port: uint16(a.Port),
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}
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}
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func (u udpAddr) toNet() *net.UDPAddr {
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return &net.UDPAddr{
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IP: u.ipv4[:],
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Port: int(u.port),
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}
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}
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