Start implementing ZIP

atalk/zip/getnetinfo.go

@@ -0,0 +1,107 @@
+/*
+   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 zip
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/sfiera/multitalk/pkg/ddp"
+	"github.com/sfiera/multitalk/pkg/ethernet"
+)
+
+type GetNetInfoPacket struct {
+	// Destination socket = 6
+	// DDP type = 6
+	// ---
+	// ZIP command = 5
+	// Flags = 0 (reserved)
+	// Four more bytes of 0 (reserved)
+	// Zone name length (1 byte)
+	ZoneName string
+}
+
+func UnmarshalGetNetInfoPacket(data []byte) (*GetNetInfoPacket, error) {
+	if len(data) < 7 {
+		return nil, fmt.Errorf("insufficient input length %d for GetNetInfo packet", len(data))
+	}
+	if data[0] != FunctionGetNetInfo {
+		return nil, fmt.Errorf("not a GetNetInfo packet (ZIP command %d != %d)", data[0], FunctionGetNetInfo)
+	}
+	slen := data[6]
+	data = data[7:]
+	if len(data) != int(slen) {
+		return nil, fmt.Errorf("wrong remaining input length %d for length=%d-prefixed string", len(data), slen)
+	}
+	return &GetNetInfoPacket{
+		ZoneName: string(data),
+	}, nil
+}
+
+type GetNetInfoReplyPacket struct {
+	// Source socket = 6
+	// DDP type = 6
+	// ---
+	// ZIP command = 6
+	ZoneInvalid  bool // 0x80
+	UseBroadcast bool // 0x40
+	OnlyOneZone  bool // 0x20
+	// Remainder of flags reserved
+	NetStart ddp.Network
+	NetEnd   ddp.Network
+	// Zone name length (1 byte)
+	ZoneName string
+	// Multicast address length (1 byte)
+	MulticastAddr ethernet.Addr
+	// Only if ZoneInvalid flag is set:
+	// Default zone length (1 byte)
+	DefaultZoneName string
+}
+
+func (p *GetNetInfoReplyPacket) Marshal() ([]byte, error) {
+	if len(p.ZoneName) > 32 {
+		return nil, fmt.Errorf("zone name too long [%d > 32]", len(p.ZoneName))
+	}
+	if len(p.DefaultZoneName) > 32 {
+		return nil, fmt.Errorf("default zone name too long [%d > 32]", len(p.DefaultZoneName))
+	}
+
+	b := bytes.NewBuffer(nil)
+	b.WriteByte(FunctionGetNetInfoReply)
+	var flags byte
+	if p.ZoneInvalid {
+		flags |= 0x80
+	}
+	if p.UseBroadcast {
+		flags |= 0x40
+	}
+	if p.OnlyOneZone {
+		flags |= 0x20
+	}
+	b.WriteByte(flags)
+	write16(b, p.NetStart)
+	write16(b, p.NetEnd)
+	b.WriteByte(byte(len(p.ZoneName)))
+	b.WriteString(p.ZoneName)
+	b.WriteByte(6)
+	b.Write(p.MulticastAddr[:])
+	if p.ZoneInvalid {
+		b.WriteByte(byte(len(p.DefaultZoneName)))
+		b.WriteString(p.DefaultZoneName)
+	}
+	return b.Bytes(), nil
+}

atalk/zip/query_reply.go

@@ -0,0 +1,36 @@
+/*
+   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 zip
+
+import "github.com/sfiera/multitalk/pkg/ddp"
+
+type QueryPacket struct {
+	Function Function // 1
+	// NetworkCount uint8
+	Networks []ddp.Network
+}
+
+type ReplyPacket struct {
+	Function Function // 2 or 8
+	// NetworkCount uint8
+	Tuples []ZoneTuple
+}
+
+type ZoneTuple struct {
+	Network  ddp.Network
+	ZoneName string
+}

atalk/zip/zip.go

@@ -0,0 +1,66 @@
+/*
+   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 zip
+
+import (
+	"bytes"
+	"fmt"
+)
+
+type Function uint8
+
+const (
+	FunctionQuery           = 1
+	FunctionReply           = 2
+	FunctionGetNetInfo      = 5
+	FunctionGetNetInfoReply = 6
+	FunctionNotify          = 7
+	FunctionExtendedReply   = 8
+)
+
+// Non-ATP packets only
+func UnmarshalPacket(data []byte) (any, error) {
+	if len(data) < 1 {
+		return nil, fmt.Errorf("insufficient input length %d for any ZIP packet", len(data))
+	}
+	switch data[0] {
+	case FunctionQuery:
+		return nil, fmt.Errorf("ZIP Query unmarshaling unimplemented")
+
+	case FunctionReply:
+		return nil, fmt.Errorf("ZIP Reply unmarshaling unimplemented")
+
+	case FunctionExtendedReply:
+		return nil, fmt.Errorf("ZIP Extended Reply unmarshaling unimplemented")
+
+	case FunctionGetNetInfo:
+		return UnmarshalGetNetInfoPacket(data)
+
+	case FunctionGetNetInfoReply:
+		return nil, fmt.Errorf("ZIP GetNetInfo Reply unmarshaling unimplemented")
+
+	case FunctionNotify:
+		return nil, fmt.Errorf("ZIP Notify unmarshaling unimplemented")
+
+	default:
+		return nil, fmt.Errorf("unknown ZIP function %d", data[0])
+	}
+}
+
+func write16[I ~uint16](b *bytes.Buffer, n I) {
+	b.Write([]byte{byte(n >> 8), byte(n & 0xff)})
+}

main.go

@@ -34,6 +34,7 @@ import (
 	"gitea.drjosh.dev/josh/jrouter/atalk"
 	"gitea.drjosh.dev/josh/jrouter/atalk/aep"
 	"gitea.drjosh.dev/josh/jrouter/atalk/nbp"
+	"gitea.drjosh.dev/josh/jrouter/atalk/zip"
 	"gitea.drjosh.dev/josh/jrouter/aurp"
 	"github.com/google/gopacket/pcap"
 	"github.com/sfiera/multitalk/pkg/ddp"
@@ -267,9 +268,10 @@ func main() {
 				case 1: // The RTMP socket
 					rtmpCh <- ddpkt
 
-				case 2: // The NIS (NBP socket)
+				case 2: // The NIS (name information socket / NBP socket)
 					if ddpkt.Proto != ddp.ProtoNBP {
 						log.Printf("NBP: invalid DDP type %d on socket 2", ddpkt.Proto)
+						continue
 					}
 
 					nbpkt, err := nbp.Unmarshal(ddpkt.Data)
@@ -292,6 +294,72 @@ func main() {
 						log.Printf("AEP: Couldn't handle: %v", err)
 					}
 
+				case 6: // The ZIS (zone information socket / ZIP socket)
+					switch ddpkt.Proto {
+					case 3: // ATP
+						log.Print("ZIP: TODO implement ATP-based ZIP requests")
+						continue
+
+					case 6: // ZIP
+						zipkt, err := zip.UnmarshalPacket(ddpkt.Data)
+						if err != nil {
+							log.Printf("ZIP: invalid packet: %v", err)
+							continue
+						}
+						switch zipkt := zipkt.(type) {
+						case *zip.GetNetInfoPacket:
+							// Only running a network with one zone for now.
+							resp := &zip.GetNetInfoReplyPacket{
+								ZoneInvalid:     zipkt.ZoneName != cfg.EtherTalk.ZoneName,
+								UseBroadcast:    true, // TODO: add multicast addr computation
+								OnlyOneZone:     true,
+								NetStart:        cfg.EtherTalk.NetStart,
+								NetEnd:          cfg.EtherTalk.NetEnd,
+								ZoneName:        zipkt.ZoneName, // has to match request
+								MulticastAddr:   ethertalk.AppleTalkBroadcast,
+								DefaultZoneName: cfg.EtherTalk.ZoneName,
+							}
+							respRaw, err := resp.Marshal()
+							if err != nil {
+								log.Printf("ZIP: couldn't marshal GetNetInfoReplyPacket: %v", err)
+								continue
+							}
+
+							// TODO: fix
+							// "In cases where a node's provisional address is
+							// invalid, routers will not be able to respond to
+							// the node in a directed manner. An address is
+							// invalid if the network number is neither in the
+							// startup range nor in the network number range
+							// assigned to the node's network. In these cases,
+							// if the request was sent via a broadcast, the
+							// routers should respond with a broadcast."
+							ddpkt.DstNet, ddpkt.DstNode, ddpkt.DstSocket = 0x0000, 0xFF, ddpkt.SrcSocket
+							ddpkt.SrcNet = myAddr.Proto.Network
+							ddpkt.SrcNode = myAddr.Proto.Node
+							ddpkt.SrcSocket = 6
+							ddpkt.Data = respRaw
+							outFrame, err := ethertalk.AppleTalk(myHWAddr, *ddpkt)
+							if err != nil {
+								log.Printf("ZIP: couldn't create EtherTalk frame: %v", err)
+								continue
+							}
+							outFrame.Dst = ethFrame.Src
+							outFrameRaw, err := ethertalk.Marshal(*outFrame)
+							if err != nil {
+								log.Printf("ZIP: couldn't marshal EtherTalk frame: %v", err)
+								continue
+							}
+							if err := pcapHandle.WritePacketData(outFrameRaw); err != nil {
+								log.Printf("ZIP: couldn't write packet data: %v", err)
+							}
+						}
+
+					default:
+						log.Printf("ZIP: invalid DDP type %d on socket 6", ddpkt.Proto)
+						continue
+					}
+
 				default:
 					log.Printf("DDP: No handler for socket %d", ddpkt.DstSocket)
 				}