/* Copyright 2024 Josh Deprez Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. */ package main import ( "errors" "fmt" "log" "gitea.drjosh.dev/josh/jrouter/atalk/nbp" "github.com/google/gopacket/pcap" "github.com/sfiera/multitalk/pkg/aarp" "github.com/sfiera/multitalk/pkg/ddp" "github.com/sfiera/multitalk/pkg/ethernet" "github.com/sfiera/multitalk/pkg/ethertalk" ) func handleNBP(pcapHandle *pcap.Handle, myHWAddr, srcHWAddr ethernet.Addr, myAddr aarp.AddrPair, cfg *config, ddpkt *ddp.ExtPacket) error { if ddpkt.Proto != ddp.ProtoNBP { return fmt.Errorf("invalid DDP type %d on socket 2", ddpkt.Proto) } nbpkt, err := nbp.Unmarshal(ddpkt.Data) if err != nil { return fmt.Errorf("invalid packet: %w", err) } log.Printf("NBP: Got %v id %d with tuples %v", nbpkt.Function, nbpkt.NBPID, nbpkt.Tuples) switch nbpkt.Function { case nbp.FunctionLkUp: // when in AppleTalk, do as Apple Internet Router does... tuple := nbpkt.Tuples[0] if tuple.Object != "jrouter" && tuple.Object != "=" { return nil } if tuple.Type != "AppleRouter" && tuple.Type != "=" { return nil } if tuple.Zone != cfg.EtherTalk.ZoneName && tuple.Zone != "*" && tuple.Zone != "" { return nil } respPkt := &nbp.Packet{ Function: nbp.FunctionLkUpReply, NBPID: nbpkt.NBPID, Tuples: []nbp.Tuple{ { Network: myAddr.Proto.Network, Node: myAddr.Proto.Node, Socket: 253, Enumerator: 0, Object: "jrouter", Type: "AppleRouter", Zone: cfg.EtherTalk.ZoneName, }, }, } respRaw, err := respPkt.Marshal() if err != nil { return fmt.Errorf("couldn't marshal LkUp-Reply: %v", err) } ddpkt.DstNet = ddpkt.SrcNet ddpkt.DstNode = ddpkt.SrcNode ddpkt.DstSocket = ddpkt.SrcSocket ddpkt.SrcNet = myAddr.Proto.Network ddpkt.SrcNode = myAddr.Proto.Node ddpkt.SrcSocket = 2 ddpkt.Data = respRaw outFrame, err := ethertalk.AppleTalk(myHWAddr, *ddpkt) if err != nil { return err } outFrame.Dst = srcHWAddr outFrameRaw, err := ethertalk.Marshal(*outFrame) if err != nil { return err } return pcapHandle.WritePacketData(outFrameRaw) case nbp.FunctionBrRq: // There must be 1! tuple := nbpkt.Tuples[0] if tuple.Zone != cfg.EtherTalk.ZoneName { // TODO: Translate it into a FwdReq and route it to the // routers with the appropriate zone(s). return errors.New("TODO: BrRq-FwdReq translation") } // If it's for the local zone, translate it to a LkUp and broadcast it back // out the EtherTalk port. // "Note: On an internet, nodes on extended networks performing lookups in // their own zone must replace a zone name of asterisk (*) with their actual // zone name before sending the packet to A-ROUTER. All nodes performing // lookups in their own zone will receive LkUp packets from themselves // (actually sent by a router). The node's NBP process should expect to // receive these packets and must reply to them." // TODO: use zone-specific multicast nbpkt.Function = nbp.FunctionLkUp nbpRaw, err := nbpkt.Marshal() if err != nil { return fmt.Errorf("couldn't marshal LkUp: %v", err) } ddpkt.DstNode = 0xFF // Broadcast node address within the dest network ddpkt.Data = nbpRaw outFrame, err := ethertalk.AppleTalk(myHWAddr, *ddpkt) if err != nil { return err } outFrameRaw, err := ethertalk.Marshal(*outFrame) if err != nil { return err } return pcapHandle.WritePacketData(outFrameRaw) default: return fmt.Errorf("TODO: handle function %v", nbpkt.Function) } }