Protocol changes to support more packet types

channel.go

@@ -2,25 +2,70 @@ package pnyx
 
 import (
 	"slices"
+  "fmt"
 )
 
 type ChannelID uint32
 
 const (
-  RootChannelID ChannelID = 0
+  MODE_CHANNEL ModeID = iota
+  MODE_RAW
 
-  MODE_RAW ModeID = iota
+  CHANNEL_JOIN byte = iota
+  CHANNEL_LEAVE
+  CHANNEL_MEMBERS
 
-  MODE_COMMAND_DATA byte = 0x00
+  RAW_DATA = iota
-  MODE_COMMAND_JOIN = 0x01
-  MODE_COMMAND_LEAVE = 0x02
 )
 
 type ModeID uint8
 type CommandID uint8
+type Permission string
 
 type Channel struct {
+  id ChannelID
   modes map[ModeID]Mode
+  sessions []SessionID
+}
+
+func(channel *Channel) Data(session *Session, mode ModeID, data []byte) []SendPacket {
+  m, has_mode := channel.modes[mode]
+  if has_mode == false {
+    return nil
+  } else {
+    return m.Data(session, channel, data)
+  }
+}
+
+func(channel *Channel) Command(session *Session, mode ModeID, command byte, data []byte) ([]SendPacket, error) {
+  if mode == MODE_CHANNEL {
+    switch command {
+    case CHANNEL_JOIN:
+      if slices.Contains(channel.sessions, session.ID) {
+        return nil, fmt.Errorf("Session %s already in channel %d, can't join", session.ID, channel.id)
+      } else {
+        channel.sessions = append(channel.sessions, session.ID)
+        return nil, nil
+      }
+    case CHANNEL_LEAVE:
+      idx := slices.Index(channel.sessions, session.ID)
+      if idx == -1 {
+        return nil, fmt.Errorf("Session %s not in channel %d, can't leave", session.ID, channel.id)
+      } else {
+        channel.sessions = slices.Delete(channel.sessions, idx, idx+1)
+        return nil, nil
+      }
+    default:
+      return nil, fmt.Errorf("Unknown MODE_CHANNEL command: 0x%02x", command)
+    }
+  } else {
+    mode, has_mode := channel.modes[mode]
+    if has_mode == false {
+      return nil, fmt.Errorf("Channel has no mode 0x%02x", mode)
+    } else {
+      return mode.Command(session, channel, command, data)
+    }
+  }
 }
 
 type SendPacket struct {
@@ -30,7 +75,8 @@ type SendPacket struct {
 
 type Mode interface {
   // Process takes incoming packets from a session and returns a list of packets to send
-  Process(*Session, *Packet) []SendPacket
+  Command(session *Session, channel *Channel, command byte, data []byte) ([]SendPacket, error)
+  Data(session *Session, channel *Channel, data []byte) []SendPacket
 }
 
 func multiplex(session *Session, packet *Packet, sessions []SessionID) []SendPacket {
@@ -50,32 +96,16 @@ func multiplex(session *Session, packet *Packet, sessions []SessionID) []SendPac
 }
 
 type RawMode struct {
-  Sessions []SessionID
 }
 
-func(mode *RawMode) Process(session *Session, packet *Packet) []SendPacket {
+func(mode *RawMode) Command(session *Session, channel *Channel, command byte, data []byte) ([]SendPacket, error) {
-  switch packet.Command {
+  return nil, fmt.Errorf("unknown raw mode command 0x%02x", command)
-  case MODE_COMMAND_JOIN:
-    if slices.Contains(mode.Sessions, session.ID) == false {
-      mode.Sessions = append(mode.Sessions, session.ID)
 }
 
-  case MODE_COMMAND_LEAVE:
+func(mode *RawMode) Data(session *Session, channel *Channel, data []byte) []SendPacket {
-    idx := slices.Index(mode.Sessions, session.ID)
+  if slices.Contains(channel.sessions, session.ID) {
-    if idx != -1 {
+    new_packet := NewChannelPeerPacket(session.Peer, channel.id, MODE_RAW, data)
-      mode.Sessions = slices.Delete(mode.Sessions, idx, idx+1)
+    return multiplex(session, new_packet, channel.sessions)
-    }
-
-  case MODE_COMMAND_DATA:
-    if slices.Contains(mode.Sessions, session.ID) {
-      new_packet := &Packet{
-        Channel: packet.Channel,
-        Mode: packet.Mode,
-        Command: MODE_COMMAND_DATA,
-        Data: append(session.Peer[:], packet.Data...),
-      }
-      return multiplex(session, new_packet, mode.Sessions)
-    }
   }
   return nil
 }

client.go

@@ -107,7 +107,7 @@ func NewClient(key ed25519.PrivateKey, remote string) (*Client, error) {
   }, nil
 }
 
-func(client *Client) Send(packet Packet) error {
+func(client *Client) Send(packet *Packet) error {
   client.ConnectionLock.Lock()
   defer client.ConnectionLock.Unlock()
 

cmd/client/main.go

@@ -180,12 +180,14 @@ func main() {
         fmt.Printf("ParsePacket Error %s - %x\n", err, data)
         continue
       }
-      peer := pnyx.PeerID(packet.Data[0:16])
+
-      if packet.Channel == pnyx.ChannelID(1) {
+      switch packet := packet.(type) {
-        decode_chan, exists := decoders[peer]
+      case pnyx.ChannelPeerPacket:
+        if packet.Channel == pnyx.ChannelID(0) {
+          decode_chan, exists := decoders[packet.Peer]
           if exists == false {
             decode_chan = make(chan[]byte, 1000)
-          decoders[peer] = decode_chan
+            decoders[packet.Peer] = decode_chan
 
             go func(decode_chan chan[]byte){
               decoder, err := opus.NewDecoder(48000, 1)
@@ -222,41 +224,25 @@ func main() {
                 }
               }
 
-          }(decoders[peer])
+            }(decoders[packet.Peer])
           }
-        decode_chan <- packet.Data[16:]
+          decode_chan <- packet.Data
         }
+      default:
+        fmt.Printf("Unhandled packet type: %s\n", packet)
       }
-  }()
-
-  err = client.Send(pnyx.Packet{
-    Channel: pnyx.ChannelID(1),
-    Mode: pnyx.MODE_RAW,
-    Command: pnyx.MODE_COMMAND_JOIN,
-    Data: nil,
-  })
-  if err != nil {
-    panic(err)
     }
+  }()
 
-  err = client.Send(pnyx.Packet{
+  join_packet, _ := pnyx.NewChannelCommandPacket(pnyx.ChannelID(0), pnyx.MODE_CHANNEL, pnyx.CHANNEL_JOIN, nil)
-    Channel: pnyx.ChannelID(2),
+  err = client.Send(join_packet)
-    Mode: pnyx.MODE_RAW,
-    Command: pnyx.MODE_COMMAND_JOIN,
-    Data: nil,
-  })
   if err != nil {
     panic(err)
   }
 
   for true {
     data := <- mic
-    err = client.Send(pnyx.Packet{
+    err = client.Send(pnyx.NewChannelDataPacket(pnyx.ChannelID(0), pnyx.MODE_RAW, data))
-      Channel: pnyx.ChannelID(1),
-      Mode: pnyx.MODE_RAW,
-      Command: pnyx.MODE_COMMAND_DATA,
-      Data: data,
-    })
     if err != nil {
       panic(err)
     }

cmd/server/main.go

@@ -23,12 +23,7 @@ func main() {
     panic(err)
   }
 
-  err = server.AddChannel(pnyx.ChannelID(1), &pnyx.RawMode{})
+  err = server.AddChannel(pnyx.ChannelID(0), &pnyx.RawMode{})
-  if err != nil {
-    panic(err)
-  }
-
-  err = server.AddChannel(pnyx.ChannelID(2), &pnyx.RawMode{})
   if err != nil {
     panic(err)
   }

notes.txt

@@ -173,3 +173,9 @@ Also this allows for the permission map to look like:
     }
   }
 }
+
+-------------------------------------------------------------------------------
+
+What would the experience be like if channels were nested?
+
+

packet.go

@@ -1,37 +1,221 @@
 package pnyx
 
 import (
+	"encoding"
 	"encoding/binary"
 	"fmt"
+
+	"github.com/google/uuid"
 )
 
+type PacketType uint8
+const (
+  PACKET_CHANNEL_COMMAND PacketType = iota
+  PACKET_CHANNEL_DATA
+  PACKET_CHANNEL_PEER
+
+  CHANNEL_HEADER_LEN int = 5
+  CHANNEL_COMMAND_LEN = CHANNEL_HEADER_LEN + COMMAND_LENGTH + ID_LENGTH
+  CHANNEL_PEER_LEN = CHANNEL_HEADER_LEN + ID_LENGTH
+)
+
+type Payload interface {
+  encoding.BinaryMarshaler
+}
+
 type Packet struct {
+  Type PacketType
+  Payload Payload
+}
+
+func(packet Packet) MarshalBinary() ([]byte, error) {
+  payload, err := packet.Payload.MarshalBinary()
+  if err != nil {
+    return nil, err
+  }
+
+  return append([]byte{byte(packet.Type)}, payload...), nil
+}
+
+func ParsePacket(data []byte) (Payload, error) {
+  if len(data) < 1 {
+    return nil, fmt.Errorf("Packet too short to parse - %d/1", len(data))
+  }
+
+  switch PacketType(data[0]) {
+  case PACKET_CHANNEL_DATA:
+    return ParseChannelDataPacket(data[1:])
+  case PACKET_CHANNEL_COMMAND:
+    return ParseChannelCommandPacket(data[1:])
+  case PACKET_CHANNEL_PEER:
+    return ParseChannelPeerPacket(data[1:])
+  default:
+    return nil, fmt.Errorf("Don't know how to parse packet type 0x%02x", data[0])
+  }
+}
+
+type ChannelHeader struct {
   Channel ChannelID
   Mode ModeID
+}
+
+func(packet ChannelHeader) MarshalBinary() ([]byte, error) {
+  p := binary.BigEndian.AppendUint32(nil, uint32(packet.Channel))
+  return append(p, byte(packet.Mode)), nil
+}
+
+func ParseChannelHeader(data []byte) (ChannelHeader, error) {
+  if len(data) < 5 {
+    return ChannelHeader{}, fmt.Errorf("Not enough bytes to parse ChannelPacket(%d/%d)", len(data), 6)
+  }
+
+  return ChannelHeader{
+    Channel: ChannelID(binary.BigEndian.Uint32(data)),
+    Mode: ModeID(data[4]),
+  }, nil
+}
+
+type ChannelCommandPacket struct {
+  ChannelHeader
   Command byte
+  ReqID uuid.UUID
   Data []byte
 }
 
-func(packet Packet) String() string {
+func NewChannelCommandPacket(channel ChannelID, mode ModeID, command byte, data []byte) (*Packet, uuid.UUID) {
-  return fmt.Sprintf("{Channel: %x, Mode: %x, Data: %x}", packet.Channel, packet.Mode, packet.Data)
+  request_id := uuid.New()
+  return &Packet{
+    Type: PACKET_CHANNEL_COMMAND,
+    Payload: ChannelCommandPacket{
+      ChannelHeader: ChannelHeader{
+        Channel: channel,
+        Mode: mode,
+      },
+      Command: command,
+      ReqID: request_id,
+      Data: data,
+    },
+  }, request_id
 }
 
-func(packet Packet) MarshalBinary() ([]byte, error) {
+func(packet ChannelCommandPacket) MarshalBinary() ([]byte, error) {
-  p := binary.BigEndian.AppendUint32(nil, uint32(packet.Channel))
+  header, err := packet.ChannelHeader.MarshalBinary()
-  p = append(p, byte(packet.Mode))
+  if err != nil {
-  p = append(p, byte(packet.Command))
+    return nil, err
-  return append(p, packet.Data...), nil 
   }
 
-func ParsePacket(data []byte) (*Packet, error) {
+  data := append(header, packet.Command)
-  if len(data) < 6 {
+  data = append(data, packet.ReqID[:]...)
-    return nil, fmt.Errorf("Not enough bytes to parse Packet(%d/%d)", len(data), 6)
+  return append(data, packet.Data...), nil
 }
 
+func ParseChannelCommandPacket(data []byte) (ChannelCommandPacket, error) {
+  if len(data) < CHANNEL_COMMAND_LEN {
+    return ChannelCommandPacket{}, fmt.Errorf("Not enough data to decode channel command packet %d/%d", len(data), CHANNEL_COMMAND_LEN)
+  }
+
+  header, err := ParseChannelHeader(data[:CHANNEL_HEADER_LEN])
+  if err != nil {
+    return ChannelCommandPacket{}, err
+  }
+
+  command := data[CHANNEL_HEADER_LEN]
+  request_id := uuid.UUID(data[CHANNEL_HEADER_LEN+COMMAND_LENGTH:])
+  return ChannelCommandPacket{
+      ChannelHeader: header,
+      Command: command,
+      ReqID: request_id,
+      Data: data[CHANNEL_COMMAND_LEN:],
+  }, nil
+}
+
+type ChannelPeerPacket struct {
+  ChannelHeader
+  Peer PeerID
+  Data []byte
+}
+
+func NewChannelPeerPacket(peer PeerID, channel ChannelID, mode ModeID, data []byte) *Packet {
   return &Packet{
-    Channel: ChannelID(binary.BigEndian.Uint32(data)),
+    Type: PACKET_CHANNEL_PEER,
-    Mode: ModeID(data[4]),
+    Payload: ChannelPeerPacket{
-    Command: data[5],
+      ChannelHeader: ChannelHeader{
-    Data: data[6:],
+        Channel: channel,
+        Mode: mode,
+      },
+      Peer: peer,
+      Data: data,
+    },
+  }
+}
+
+func(packet ChannelPeerPacket) MarshalBinary() ([]byte, error) {
+  header, err := packet.ChannelHeader.MarshalBinary()
+  if err != nil {
+    return nil, err
+  }
+
+  data := append(header, packet.Peer[:]...)
+  return append(data, packet.Data...), nil
+}
+
+func ParseChannelPeerPacket(data []byte) (ChannelPeerPacket, error) {
+  if len(data) < CHANNEL_PEER_LEN {
+    return ChannelPeerPacket{}, fmt.Errorf("Not enough bytes to parse ServerChannelPacket: %d/%d", len(data), ID_LENGTH)
+  }
+
+  header, err := ParseChannelHeader(data)
+  if err != nil {
+    return ChannelPeerPacket{}, err
+  }
+
+  return ChannelPeerPacket{
+    ChannelHeader: header,
+    Peer: PeerID(data[CHANNEL_HEADER_LEN:]),
+    Data: data[CHANNEL_PEER_LEN:],
+  }, nil
+}
+
+
+type ChannelDataPacket struct {
+  ChannelHeader
+  Data []byte
+}
+
+func NewChannelDataPacket(channel ChannelID, mode ModeID, data []byte) *Packet {
+  return &Packet{
+    Type: PACKET_CHANNEL_DATA,
+    Payload: ChannelDataPacket{
+      ChannelHeader: ChannelHeader{
+        Channel: channel,
+        Mode: mode,
+      },
+      Data: data,
+    },
+  }
+}
+
+func(packet ChannelDataPacket) MarshalBinary() ([]byte, error) {
+  header, err := packet.ChannelHeader.MarshalBinary()
+  if err != nil {
+    return nil, err
+  }
+
+  return append(header, packet.Data...), nil
+}
+
+func ParseChannelDataPacket(data []byte) (ChannelDataPacket, error) {
+  if len(data) < CHANNEL_HEADER_LEN {
+    return ChannelDataPacket{}, fmt.Errorf("Not enough data to parse ChannelDataPacket")
+  }
+
+  header, err := ParseChannelHeader(data)
+  if err != nil {
+    return ChannelDataPacket{}, nil
+  }
+
+  return ChannelDataPacket{
+    ChannelHeader: header,
+    Data: data[CHANNEL_HEADER_LEN:],
   }, nil
 }

server.go

@@ -18,6 +18,8 @@ const (
  SERVER_SEND_BUFFER_SIZE = 2048
 )
 
+type RoleID uint32
+
 type ServerSession struct {
   Session
   LastSeen time.Time
@@ -40,6 +42,8 @@ type Server struct {
 
   channels_lock sync.RWMutex
   channels map[ChannelID]*Channel
+
+  peers map[PeerID][]RoleID
 }
 
 func NewServer(key ed25519.PrivateKey) (*Server, error) {
@@ -64,6 +68,8 @@ func NewServer(key ed25519.PrivateKey) (*Server, error) {
 
     sessions: map[SessionID]*ServerSession{},
     channels: map[ChannelID]*Channel{},
+
+    peers: map[PeerID][]RoleID{},
   }
   server.active.Store(false)
   return server, nil
@@ -83,10 +89,6 @@ func(server *Server) RemoveChannel(id ChannelID) error {
 }
 
 func(server *Server) AddChannel(id ChannelID, modes ...Mode) error {
-  if id == RootChannelID {
-    return fmt.Errorf("Cannot use root channel ID as real channel")
-  }
-
   server.channels_lock.Lock()
   defer server.channels_lock.Unlock()
 
@@ -111,7 +113,9 @@ func(server *Server) AddChannel(id ChannelID, modes ...Mode) error {
   }
 
   server.channels[id] = &Channel{
+    id: id,
     modes: mode_map,
+    sessions: []SessionID{},
   }
 
   return nil
@@ -144,7 +148,7 @@ func(server *Server) listen_udp() {
   for true {
     read, from, err := server.connection.ReadFromUDP(buf[:])
     if err == nil {
-      var packet_type PacketType = PacketType(buf[0])
+      var packet_type SessionPacketType = SessionPacketType(buf[0])
       switch packet_type {
       case SESSION_OPEN:
         session_open, ecdh_private, err := NewSessionOpen(server.key)
@@ -221,24 +225,45 @@ func(server *Server) listen_udp() {
               server.Log("SESSION_DATA_IN(%s) parse error - %s", session.ID, err)
             }
 
-            if packet.Channel == RootChannelID {
+            switch packet := packet.(type) {
-              // TODO process commands on the root channel
+            case ChannelDataPacket:
-            } else {
               var result []SendPacket = nil
+
               server.channels_lock.RLock()
               channel, exists := server.channels[packet.Channel]
               if exists == true {
-                mode, exists := channel.modes[packet.Mode]
+                result = channel.Data(&session.Session, packet.Mode, packet.Data)
-                if exists == true {
-                  result = mode.Process(&session.Session, packet)
               }
+              server.channels_lock.RUnlock()
+
+              if exists == false {
+                server.Log("Packet for unknown channel %d", packet.Channel)
+              } else if len(result) > 0 {
+                //TODO: handle overflow
+                server.send_packets<-result
+              }
+
+            case ChannelCommandPacket:
+              var result []SendPacket = nil
+
+              server.channels_lock.RLock()
+              channel, exists := server.channels[packet.Channel]
+              if exists == true {
+                result, err = channel.Command(&session.Session, packet.Mode, packet.Command, packet.Data)
               }
               server.channels_lock.RUnlock()
 
-              if result != nil {
+              if exists == false {
+                server.Log("Packet for unknown channel %d", packet.Channel)
+              } else if err != nil {
+                server.Log("Error processing %+v - %s", packet, err)
+              } else if len(result) > 0 {
                 //TODO: handle overflow
                 server.send_packets<-result
               }
+
+            default:
+              server.Log("Unhandled packet type from session %s - 0x%02x", session.ID, err)
             }
 
           }

session.go

@@ -34,7 +34,7 @@ type Session struct {
   iv_generator mrand.Source64
 }
 
-type PacketType uint8
+type SessionPacketType uint8
 const (
   ID_LENGTH = 16
   IV_LENGTH = aes.BlockSize
@@ -51,7 +51,7 @@ const (
   /*
     pnyx session packets
   */
-  SESSION_OPEN PacketType = iota
+  SESSION_OPEN SessionPacketType = iota
   SESSION_CONNECT
   SESSION_CLOSE
   SESSION_DATA