Moved session packet handlers to functions for reasability

server.go

@@ -141,212 +141,235 @@ func(server *Server) Stop() error {
 
 const SESSION_BUFFER_SIZE = 256
 
-func(server *Server) listen_udp() {
-  server.Log("Started server on %s", server.connection.LocalAddr())
+func(server *Server) handle_session_open(client_session_open []byte, from *net.UDPAddr) error {
+  session_open, ecdh_private, err := NewSessionOpen(server.key)
+  if err != nil {
+    return err
+  }
 
-  var buf [SERVER_UDP_BUFFER_SIZE]byte
-  for true {
-    read, from, err := server.connection.ReadFromUDP(buf[:])
-    if err == nil {
-      var packet_type SessionPacketType = SessionPacketType(buf[0])
-      switch packet_type {
-      case SESSION_OPEN:
-        session_open, ecdh_private, err := NewSessionOpen(server.key)
-        if err != nil {
-          server.Log("NewSessionOpen error - %s: %x", err, buf[COMMAND_LENGTH:read])
-          continue
-        }
+  session, err := ParseSessionOpen(ecdh_private, client_session_open)
+  if err != nil {
+    return err
+  }
 
-        session, err := ParseSessionOpen(ecdh_private, buf[COMMAND_LENGTH:read])
-        if err != nil {
-          server.Log("ParseSessionOpen error - %s: %x", err, buf[COMMAND_LENGTH:read])
-          continue
+  server.sessions_lock.Lock()
+  server.sessions[session.ID] = &ServerSession{
+    Session: session,
+    LastSeen: time.Now(),
+    IncomingPackets: make(chan[]byte, SESSION_BUFFER_SIZE),
+    OutgoingPackets: make(chan *Packet, SESSION_BUFFER_SIZE),
+  }
+  server.sessions_lock.Unlock()
+
+  go func(session *ServerSession, server *Server){
+    server.Log("Starting session outgoing goroutine %s", session.ID)
+    for true {
+      packet := <- session.OutgoingPackets
+      if packet == nil {
+        break
+      }
+
+      if session.remote == nil {
+        server.Log("SESSION_DATA_OUT(%s) error - no remote to send to", session.ID)
+        continue
+      }
+
+      packet_data, err := packet.MarshalBinary()
+      if err != nil {
+        server.Log("SESSION_DATA_OUT(%s) marshal error - %s", session.ID, err)
+        continue
+      }
+
+      encrypted, err := NewSessionData(&session.Session, packet_data)
+      if err != nil {
+        server.Log("SESSION_DATA_OUT(%s) error - %s", session.ID, err)
+        continue
+      }
+
+      _, err = server.connection.WriteToUDP(encrypted, session.remote)
+      if err != nil {
+        server.Log("SESSION_DATA_OUT(%s) write error - %s", session.ID, err)
+        continue
+      }
+    }
+    server.Log("Stopping session outgoing goroutine %s", session.ID)
+  }(server.sessions[session.ID], server)
+
+  go func(session *ServerSession, server *Server){
+    server.Log("Starting session incoming goroutine %s", session.ID)
+    for true {
+      encrypted := <- session.IncomingPackets
+      if encrypted == nil {
+        break
+      }
+
+      data, err := ParseSessionData(&session.Session, encrypted)
+      if err != nil {
+        server.Log("SESSION_DATA_IN(%s) error - %s", session.ID, err)
+        continue
+      }
+
+      packet, err := ParsePacket(data)
+      if err != nil {
+        server.Log("SESSION_DATA_IN(%s) parse error - %s", session.ID, err)
+      }
+
+      switch packet := packet.(type) {
+      case ChannelDataPacket:
+        var result []SendPacket = nil
+
+        server.channels_lock.RLock()
+        channel, exists := server.channels[packet.Channel]
+        if exists == true {
+          result = channel.Data(&session.Session, packet.Mode, packet.Data)
         }
+        server.channels_lock.RUnlock()
 
-        server.sessions_lock.Lock()
-        server.sessions[session.ID] = &ServerSession{
-          Session: session,
-          LastSeen: time.Now(),
-          IncomingPackets: make(chan[]byte, SESSION_BUFFER_SIZE),
-          OutgoingPackets: make(chan *Packet, SESSION_BUFFER_SIZE),
+        if exists == false {
+          server.Log("Packet for unknown channel %d", packet.Channel)
+        } else if len(result) > 0 {
+          //TODO: handle overflow
+          server.send_packets<-result
         }
-        server.sessions_lock.Unlock()
-
-        go func(session *ServerSession, server *Server){
-          server.Log("Starting session outgoing goroutine %s", session.ID)
-          for true {
-            packet := <- session.OutgoingPackets
-            if packet == nil {
-              break
-            }
-
-            if session.remote == nil {
-              server.Log("SESSION_DATA_OUT(%s) error - no remote to send to", session.ID)
-              continue
-            }
-
-            packet_data, err := packet.MarshalBinary()
-            if err != nil {
-              server.Log("SESSION_DATA_OUT(%s) marshal error - %s", session.ID, err)
-              continue
-            }
-
-            encrypted, err := NewSessionData(&session.Session, packet_data)
-            if err != nil {
-              server.Log("SESSION_DATA_OUT(%s) error - %s", session.ID, err)
-              continue
-            }
-
-            _, err = server.connection.WriteToUDP(encrypted, session.remote)
-            if err != nil {
-              server.Log("SESSION_DATA_OUT(%s) write error - %s", session.ID, err)
-              continue
-            }
-          }
-          server.Log("Stopping session outgoing goroutine %s", session.ID)
-        }(server.sessions[session.ID], server)
-
-        go func(session *ServerSession, server *Server){
-          server.Log("Starting session incoming goroutine %s", session.ID)
-          for true {
-            encrypted := <- session.IncomingPackets
-            if encrypted == nil {
-              break
-            }
-
-            data, err := ParseSessionData(&session.Session, encrypted)
-            if err != nil {
-              server.Log("SESSION_DATA_IN(%s) error - %s", session.ID, err)
-              continue
-            }
-
-            packet, err := ParsePacket(data)
-            if err != nil {
-              server.Log("SESSION_DATA_IN(%s) parse error - %s", session.ID, err)
-            }
-
-            switch packet := packet.(type) {
-            case ChannelDataPacket:
-              var result []SendPacket = nil
-
-              server.channels_lock.RLock()
-              channel, exists := server.channels[packet.Channel]
-              if exists == true {
-                result = channel.Data(&session.Session, packet.Mode, packet.Data)
-              }
-              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 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)
-            }
-
-          }
-          server.Log("Stopping session incoming goroutine %s", session.ID)
-        }(server.sessions[session.ID], server)
-
-        _, err = server.connection.WriteToUDP(session_open, from)
-        if err != nil {
-          server.Log("WriteToUDP error %s", err) 
-          continue
+
+      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.Log("Started session %s with %s", session.ID, session.Peer)
+        server.channels_lock.RUnlock()
 
-      case SESSION_CONNECT:
-        session_id := SessionID(buf[COMMAND_LENGTH:COMMAND_LENGTH+ID_LENGTH])
-        session, exists := server.sessions[session_id]
         if exists == false {
-          server.Log("Session %s does not exist, can't connect", session_id)
-          continue
+          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
         }
 
-        _, err := ParseSessionConnect(buf[COMMAND_LENGTH+ID_LENGTH:read], session.secret)
-        if err != nil {
-          server.Log("Error parsing session connect: %s", err)
-          continue
-        }
+      default:
+        server.Log("Unhandled packet type from session %s - 0x%02x", session.ID, err)
+      }
+
+    }
+    server.Log("Stopping session incoming goroutine %s", session.ID)
+  }(server.sessions[session.ID], server)
+
+  _, err = server.connection.WriteToUDP(session_open, from)
+  if err != nil {
+    return err
+  }
+  server.Log("Started session %s with %s", session.ID, session.Peer)
+  return nil
+}
+
+func(server *Server) handle_session_connect(client_session_connect []byte, from *net.UDPAddr) error {
+  session_id := SessionID(client_session_connect[:ID_LENGTH])
+  session, exists := server.sessions[session_id]
+  if exists == false {
+    return fmt.Errorf("Session %s does not exist, can't connect", session_id)
+  }
 
-        // TODO: fix, was client_addr but the client doesnt know it's nat assignment
-        session.remote = from
-        session.LastSeen = time.Now()
-        
-        // TODO: Make a better server hello
-        server_hello, err := NewSessionData(&session.Session, []byte("hello"))
+  _, err := ParseSessionConnect(client_session_connect[ID_LENGTH:], session.secret)
+  if err != nil {
+    return err
+  }
+
+  // TODO: fix, was client_addr but the client doesnt know it's nat assignment
+  session.remote = from
+  session.LastSeen = time.Now()
+
+  // TODO: Make a better server hello
+  server_hello, err := NewSessionData(&session.Session, []byte("hello"))
+  if err != nil {
+    return err
+  }
+
+  _, err = server.connection.WriteToUDP(server_hello, session.remote)
+  if err != nil {
+    return err
+  }
+  server.Log("Sent server_hello for %s to %s(from %s)", session.ID, session.remote, from) 
+  return nil
+}
+
+func(server *Server) handle_session_close(client_session_close []byte, from *net.UDPAddr) error {
+  session_id := SessionID(client_session_close[:ID_LENGTH])
+  session, exists := server.sessions[session_id]
+  if exists == false {
+    return fmt.Errorf("Session %s does not exist, can't close", session_id)
+  }
+
+  err := ParseSessionClose(&session.Session, client_session_close[ID_LENGTH:])
+  if err != nil {
+    return err
+  }
+
+  server.sessions_lock.Lock()
+  server.close_session(session)
+  server.sessions_lock.Unlock()
+
+  server.Log("Session %s closed", session_id)
+  return nil
+}
+
+func(server *Server) handle_session_data(data []byte, from *net.UDPAddr) error {
+  session_id := SessionID(data[:ID_LENGTH])
+  session, exists := server.sessions[session_id]
+  if exists == false {
+    return fmt.Errorf("Session %s does not exist, can't receive data", session_id)
+  }
+
+  session.LastSeen = time.Now()
+
+  buf_copy := make([]byte, len(data) - ID_LENGTH)
+  copy(buf_copy, data[ID_LENGTH:])
+
+  select {
+  case session.IncomingPackets<-buf_copy:
+    return nil
+  default:
+    return fmt.Errorf("Dropped packet to session %s", session_id)
+  }
+}
+
+func(server *Server) listen_udp() {
+  server.Log("Started server on %s", server.connection.LocalAddr())
+
+  var buf [SERVER_UDP_BUFFER_SIZE]byte
+  for true {
+    read, from, err := server.connection.ReadFromUDP(buf[:])
+    if err == nil {
+      var packet_type SessionPacketType = SessionPacketType(buf[0])
+      switch packet_type {
+      case SESSION_OPEN:
+        err := server.handle_session_open(buf[COMMAND_LENGTH:read], from)
         if err != nil {
-          server.Log("Error generating server hello: %s", err)
-          continue
+          server.Log("handle_session_open erorr - %s", err)
         }
 
-        _, err = server.connection.WriteToUDP(server_hello, session.remote)
+      case SESSION_CONNECT:
+        err := server.handle_session_connect(buf[COMMAND_LENGTH:read], from)
         if err != nil {
-          server.Log("Error sending server hello: %s", err)
-          continue
+          server.Log("handle_session_connect error - %s", err)
         }
-        server.Log("Sent server_hello for %s to %s(from %s)", session.ID, session.remote, from) 
 
       case SESSION_CLOSE:
-        session_id := SessionID(buf[COMMAND_LENGTH:COMMAND_LENGTH+ID_LENGTH])
-        session, exists := server.sessions[session_id]
-        if exists == false {
-          server.Log("Session %s does not exist, can't close", session_id)
-          continue
-        }
-
-        err := ParseSessionClose(&session.Session, buf[COMMAND_LENGTH+ID_LENGTH:read])
+        err := server.handle_session_close(buf[COMMAND_LENGTH:read], from)
         if err != nil {
-          server.Log("Session close error for %s - %s", session_id, err)
-          continue
+          server.Log("handle_session_close error - %s", err)
         }
 
-        server.sessions_lock.Lock()
-        server.close_session(session)
-        server.sessions_lock.Unlock()
-
-        server.Log("Session %s closed", session_id)
-
       case SESSION_DATA:
-        session_id := SessionID(buf[COMMAND_LENGTH:COMMAND_LENGTH+ID_LENGTH])
-        session, exists := server.sessions[session_id]
-        if exists == false {
-          server.Log("Session %s does not exist, can't receive data", session_id)
-          continue
+        err := server.handle_session_data(buf[COMMAND_LENGTH:read], from)
+        if err != nil {
+          server.Log("handle_session_data error - %s", err)
         }
 
-        session.LastSeen = time.Now()
-
-        buf_copy := make([]byte, read - COMMAND_LENGTH - ID_LENGTH)
-        copy(buf_copy, buf[COMMAND_LENGTH+ID_LENGTH:read])
-
-        select {
-        case session.IncomingPackets<-buf_copy:
-        default:
-          server.Log("Dropped packet to session %s", session_id)
-        }
       default:
         server.Log("Unhandled packet type 0x%04x from %s: %+v", packet_type, from, buf[COMMAND_LENGTH:read])
       }