1 files changed, 66 insertions, 63 deletions
diff --git a/rudp/rudp.go b/rudp/rudp.go
index 6b96b56..faf67d9 100644
--- a/rudp/rudp.go
+++ b/rudp/rudp.go
@@ -1,21 +1,44 @@
 /*
 Package rudp implements the low-level Minetest protocol described at
 https://dev.minetest.net/Network_Protocol#Low-level_protocol.
-
-All exported functions and methods in this package are safe for concurrent use
-by multiple goroutines.
 */
 package rudp
 
-import "encoding/binary"
+import (
+	"encoding/binary"
+	"errors"
+	"io"
+	"time"
+)
 
 var be = binary.BigEndian
 
-// protoID must be at the start of every network packet.
+/*
+UDP packet format:
+
+	protoID
+	src PeerID
+	channel uint8
+	rawType...
+*/
+
+var ErrTimedOut = errors.New("timed out")
+
+const (
+	ConnTimeout = 30 * time.Second
+	PingTimeout = 5 * time.Second
+)
+
+const (
+	MaxRelPktSize   = 32439825
+	MaxUnrelPktSize = 32636430
+)
+
+// protoID must be at the start of every UDP packet.
 const protoID uint32 = 0x4f457403
 
-// PeerIDs aren't actually used to identify peers, network addresses are,
-// these just exist for backward compatability.
+// PeerIDs aren't actually used to identify peers, IP addresses and ports are,
+// these just exist for backward compatibility.
 type PeerID uint16
 
 const (
@@ -29,79 +52,59 @@ const (
 	PeerIDCltMin
 )
 
-// ChannelCount is the maximum channel number + 1.
-const ChannelCount = 3
-
-/*
-rawPkt.Data format (big endian):
-
-	rawType
-	switch rawType {
-	case rawTypeCtl:
-		ctlType
-		switch ctlType {
-		case ctlAck:
-			// Tells peer you received a rawTypeRel
-			// and it doesn't need to resend it.
-			seqnum
-		case ctlSetPeerId:
-			// Tells peer to send packets with this Src PeerID.
-			PeerId
-		case ctlPing:
-			// Sent to prevent timeout.
-		case ctlDisco:
-			// Tells peer that you disconnected.
-		}
-	case rawTypeOrig:
-		Pkt.(Data)
-	case rawTypeSplit:
-		// Packet larger than MaxNetPktSize split into smaller packets.
-		// Packets with I >= Count should be ignored.
-		// Once all Count chunks are recieved, they are sorted by I and
-		// concatenated to make a Pkt.(Data).
-		seqnum // Identifies split packet.
-		Count, I uint16
-		Chunk...
-	case rawTypeRel:
-		// Resent until a ctlAck with same seqnum is recieved.
-		// seqnums are sequencial and start at seqnumInit,
-		// These should be processed in seqnum order.
-		seqnum
-		rawPkt.Data
-	}
-*/
-type rawPkt struct {
-	Data  []byte
-	ChNo  uint8
-	Unrel bool
-}
-
 type rawType uint8
 
 const (
-	rawTypeCtl rawType = iota
-	rawTypeOrig
-	rawTypeSplit
-	rawTypeRel
+	rawCtl rawType = iota
+	// ctlType...
+
+	rawOrig
+	// data...
+
+	rawSplit
+	// seqnum
+	// n, i uint16
+	// data...
+
+	rawRel
+	// seqnum
+	// rawType...
 )
 
 type ctlType uint8
 
 const (
 	ctlAck ctlType = iota
+	// seqnum
+
 	ctlSetPeerID
-	ctlPing
+	// PeerID
+
+	ctlPing // Sent to prevent timeout.
+
 	ctlDisco
 )
 
 type Pkt struct {
-	Data  []byte
-	ChNo  uint8
+	io.Reader
+	PktInfo
+}
+
+// Reliable packets in a channel are be received in the order they are sent in.
+// A Channel must be less than ChannelCount.
+type Channel uint8
+
+const ChannelCount Channel = 3
+
+type PktInfo struct {
+	Channel
+
+	// Unrel (unreliable) packets may be dropped, duplicated or reordered.
 	Unrel bool
 }
 
 // seqnums are sequence numbers used to maintain reliable packet order
-// and to identify split packets.
+// and identify split packets.
 type seqnum uint16
 
-const seqnumInit seqnum = 65500
+const initSeqnum seqnum = 65500