feat: support tuicV5

transport/tuic/v5/frag.go

@@ -0,0 +1,80 @@
+package v5
+
+import (
+	"bytes"
+
+	"github.com/metacubex/quic-go"
+)
+
+func fragWriteNative(quicConn quic.Connection, packet Packet, buf *bytes.Buffer, fragSize int) (err error) {
+	fullPayload := packet.DATA
+	off := 0
+	fragID := uint8(0)
+	fragCount := uint8((len(fullPayload) + fragSize - 1) / fragSize) // round up
+	packet.FRAG_TOTAL = fragCount
+	for off < len(fullPayload) {
+		payloadSize := len(fullPayload) - off
+		if payloadSize > fragSize {
+			payloadSize = fragSize
+		}
+		frag := packet
+		frag.FRAG_ID = fragID
+		frag.SIZE = uint16(payloadSize)
+		frag.DATA = fullPayload[off : off+payloadSize]
+		off += payloadSize
+		fragID++
+		buf.Reset()
+		err = frag.WriteTo(buf)
+		if err != nil {
+			return
+		}
+		data := buf.Bytes()
+		err = quicConn.SendMessage(data)
+		if err != nil {
+			return
+		}
+		packet.ADDR.TYPE = AtypNone // avoid "fragment 2/2: address in non-first fragment"
+	}
+	return
+}
+
+type deFragger struct {
+	pkgID uint16
+	frags []*Packet
+	count uint8
+}
+
+func (d *deFragger) Feed(m Packet) *Packet {
+	if m.FRAG_TOTAL <= 1 {
+		return &m
+	}
+	if m.FRAG_ID >= m.FRAG_TOTAL {
+		// wtf is this?
+		return nil
+	}
+	if d.count == 0 || m.PKT_ID != d.pkgID {
+		// new message, clear previous state
+		d.pkgID = m.PKT_ID
+		d.frags = make([]*Packet, m.FRAG_TOTAL)
+		d.count = 1
+		d.frags[m.FRAG_ID] = &m
+	} else if d.frags[m.FRAG_ID] == nil {
+		d.frags[m.FRAG_ID] = &m
+		d.count++
+		if int(d.count) == len(d.frags) {
+			// all fragments received, assemble
+			var data []byte
+			for _, frag := range d.frags {
+				data = append(data, frag.DATA...)
+			}
+			p := d.frags[0] // recover from first fragment
+			p.SIZE = uint16(len(data))
+			p.DATA = data
+			p.FRAG_ID = 0
+			p.FRAG_TOTAL = 1
+			d.count = 0
+			return p
+		}
+	}
+	return nil
+}