76 lines
2.3 KiB
Go
76 lines
2.3 KiB
Go
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/*
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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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"fmt"
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"log"
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"gitea.drjosh.dev/josh/jrouter/atalk/nbp"
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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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func handleNBPInAURP(pcapHandle *pcap.Handle, myHWAddr ethernet.Addr, ddpkt *ddp.ExtPacket) error {
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if ddpkt.Proto != ddp.ProtoNBP {
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return fmt.Errorf("invalid DDP type %d on socket 2", ddpkt.Proto)
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}
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nbpkt, err := nbp.Unmarshal(ddpkt.Data)
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if err != nil {
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return fmt.Errorf("invalid NBP packet: %v", err)
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}
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if nbpkt.Function != nbp.FunctionFwdReq {
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// It's something else??
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return fmt.Errorf("can't handle %v", nbpkt.Function)
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}
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if len(nbpkt.Tuples) < 1 {
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return fmt.Errorf("no tuples in NBP packet")
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}
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log.Printf("NBP/DDP/AURP: Converting FwdReq to LkUp (%v)", nbpkt.Tuples[0])
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// Convert it to a LkUp and broadcast on EtherTalk
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// TODO: use zone-specific multicast
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nbpkt.Function = nbp.FunctionLkUp
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nbpRaw, err := nbpkt.Marshal()
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if err != nil {
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return fmt.Errorf("couldn't marshal LkUp: %v", err)
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}
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// "If the destination network is extended, however, the router must also
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// change the destination network number to $0000, so that the packet is
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// received by all nodes on the network (within the correct zone multicast
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// address)."
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ddpkt.DstNet = 0x0000
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ddpkt.DstNode = 0xFF // Broadcast node address within the dest network
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ddpkt.Data = nbpRaw
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outFrame, err := ethertalk.AppleTalk(myHWAddr, *ddpkt)
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if err != nil {
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return err
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}
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// TODO: outFrame.Dst = zone-specific multicast address
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outFrameRaw, err := ethertalk.Marshal(*outFrame)
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if err != nil {
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return err
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}
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return pcapHandle.WritePacketData(outFrameRaw)
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}
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