157 lines
4.6 KiB
Go
157 lines
4.6 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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"gitea.drjosh.dev/josh/jrouter/atalk/atp"
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"gitea.drjosh.dev/josh/jrouter/atalk/zip"
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"github.com/google/gopacket/pcap"
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"github.com/sfiera/multitalk/pkg/aarp"
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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 handleZIP(pcapHandle *pcap.Handle, srcHWAddr, myHWAddr ethernet.Addr, myAddr aarp.AddrPair, cfg *config, zones *ZoneTable, ddpkt *ddp.ExtPacket) error {
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switch ddpkt.Proto {
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case 3: // ATP
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atpkt, err := atp.UnmarshalPacket(ddpkt.Data)
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if err != nil {
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return err
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}
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switch atpkt := atpkt.(type) {
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case *atp.TReq:
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gzl, err := zip.UnmarshalTReq(atpkt)
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if err != nil {
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return err
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}
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// TODO: handle this in a more transactiony way
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resp := &zip.GetZonesReplyPacket{
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TID: gzl.TID,
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LastFlag: true, // TODO: support multiple response packets
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}
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switch gzl.Function {
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case zip.FunctionGetZoneList:
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resp.Zones = zones.AllNames()
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case zip.FunctionGetLocalZones:
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resp.Zones = zones.LocalNames()
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case zip.FunctionGetMyZone:
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return fmt.Errorf("TODO: support GetMyZone?")
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}
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respATP, err := resp.MarshalTResp()
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if err != nil {
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return err
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}
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ddpBody, err := respATP.Marshal()
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if err != nil {
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return err
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}
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respDDP := ddp.ExtPacket{
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ExtHeader: ddp.ExtHeader{
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DstNet: ddpkt.SrcNet,
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DstNode: ddpkt.SrcNode,
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DstSocket: ddpkt.SrcSocket,
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SrcNet: myAddr.Proto.Network,
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SrcNode: myAddr.Proto.Node,
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SrcSocket: 6,
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Proto: ddp.ProtoATP,
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},
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Data: ddpBody,
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}
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outFrame, err := ethertalk.AppleTalk(myHWAddr, respDDP)
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if err != nil {
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return err
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}
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outFrame.Dst = srcHWAddr
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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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case *atp.TResp:
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return fmt.Errorf("TODO: support handling ZIP ATP replies?")
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default:
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return fmt.Errorf("unsupported ATP packet type %T for ZIP", atpkt)
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}
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case 6: // ZIP
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zipkt, err := zip.UnmarshalPacket(ddpkt.Data)
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if err != nil {
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return err
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}
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switch zipkt := zipkt.(type) {
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case *zip.GetNetInfoPacket:
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// Only running a network with one zone for now.
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resp := &zip.GetNetInfoReplyPacket{
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ZoneInvalid: zipkt.ZoneName != cfg.EtherTalk.ZoneName,
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UseBroadcast: true, // TODO: add multicast addr computation
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OnlyOneZone: true,
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NetStart: cfg.EtherTalk.NetStart,
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NetEnd: cfg.EtherTalk.NetEnd,
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ZoneName: zipkt.ZoneName, // has to match request
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MulticastAddr: ethertalk.AppleTalkBroadcast,
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DefaultZoneName: cfg.EtherTalk.ZoneName,
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}
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respRaw, err := resp.Marshal()
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if err != nil {
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return fmt.Errorf("couldn't marshal GetNetInfoReplyPacket: %w", err)
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}
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// TODO: fix
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// "In cases where a node's provisional address is
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// invalid, routers will not be able to respond to
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// the node in a directed manner. An address is
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// invalid if the network number is neither in the
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// startup range nor in the network number range
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// assigned to the node's network. In these cases,
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// if the request was sent via a broadcast, the
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// routers should respond with a broadcast."
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ddpkt.DstNet, ddpkt.DstNode, ddpkt.DstSocket = 0x0000, 0xFF, ddpkt.SrcSocket
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ddpkt.SrcNet = myAddr.Proto.Network
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ddpkt.SrcNode = myAddr.Proto.Node
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ddpkt.SrcSocket = 6
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ddpkt.Data = respRaw
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outFrame, err := ethertalk.AppleTalk(myHWAddr, *ddpkt)
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if err != nil {
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return fmt.Errorf("couldn't create EtherTalk frame: %w", err)
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}
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outFrame.Dst = srcHWAddr
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outFrameRaw, err := ethertalk.Marshal(*outFrame)
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if err != nil {
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return fmt.Errorf("couldn't marshal EtherTalk frame: %w", err)
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}
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if err := pcapHandle.WritePacketData(outFrameRaw); err != nil {
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return fmt.Errorf("couldn't write packet data: %w", err)
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}
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return nil
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default:
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return fmt.Errorf("TODO: handle type %T", zipkt)
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}
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default:
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return fmt.Errorf("invalid DDP type %d on socket 6", ddpkt.Proto)
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}
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}
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