1 files changed, 142 insertions, 0 deletions
diff --git a/weed/udptransfer/packet.go b/weed/udptransfer/packet.go
new file mode 100644
index 000000000..2413f1ccf
--- /dev/null
+++ b/weed/udptransfer/packet.go
@@ -0,0 +1,142 @@
+package udptransfer
+
+import (
+	"encoding/binary"
+	"fmt"
+)
+
+const (
+	_F_NIL  = 0
+	_F_SYN  = 1
+	_F_ACK  = 1 << 1
+	_F_SACK = 1 << 2
+	_F_TIME = 1 << 3
+	_F_DATA = 1 << 4
+	// reserved  = 1 << 5
+	_F_RESET = 1 << 6
+	_F_FIN   = 1 << 7
+)
+
+var packetTypeNames = map[byte]string{
+	0:   "NOOP",
+	1:   "SYN",
+	2:   "ACK",
+	3:   "SYN+ACK",
+	4:   "SACK",
+	8:   "TIME",
+	12:  "SACK+TIME",
+	16:  "DATA",
+	64:  "RESET",
+	128: "FIN",
+	192: "FIN+RESET",
+}
+
+const (
+	_S_FIN = iota
+	_S_FIN0
+	_S_FIN1
+	_S_SYN0
+	_S_SYN1
+	_S_EST0
+	_S_EST1
+)
+
+// Magic-6 | TH-10 | CH-10 | payload
+const (
+	_MAGIC_SIZE = 6
+	_TH_SIZE    = 10 + _MAGIC_SIZE
+	_CH_SIZE    = 10
+	_AH_SIZE    = _TH_SIZE + _CH_SIZE
+)
+
+const (
+	// Max UDP payload: 1500 MTU - 20 IP hdr - 8 UDP hdr  = 1472 bytes
+	// Then: MSS = 1472-26 = 1446
+	// And For ADSL: 1446-8 = 1438
+	_MSS = 1438
+)
+
+const (
+	_SENT_OK = 0xff
+)
+
+type packet struct {
+	seq     uint32
+	ack     uint32
+	flag    uint8
+	scnt    uint8
+	payload []byte
+	buffer  []byte
+}
+
+func (p *packet) marshall(id connID) []byte {
+	buf := p.buffer
+	if buf == nil {
+		buf = make([]byte, _AH_SIZE+len(p.payload))
+		copy(buf[_TH_SIZE+10:], p.payload)
+	}
+	binary.BigEndian.PutUint16(buf[_MAGIC_SIZE:], uint16(len(buf)))
+	binary.BigEndian.PutUint32(buf[_MAGIC_SIZE+2:], id.rid)
+	binary.BigEndian.PutUint32(buf[_MAGIC_SIZE+6:], id.lid)
+	binary.BigEndian.PutUint32(buf[_TH_SIZE:], p.seq)
+	binary.BigEndian.PutUint32(buf[_TH_SIZE+4:], p.ack)
+	buf[_TH_SIZE+8] = p.flag
+	buf[_TH_SIZE+9] = p.scnt
+	return buf
+}
+
+func unmarshall(pk *packet, buf []byte) {
+	if len(buf) >= _CH_SIZE {
+		pk.seq = binary.BigEndian.Uint32(buf)
+		pk.ack = binary.BigEndian.Uint32(buf[4:])
+		pk.flag = buf[8]
+		pk.scnt = buf[9]
+		pk.payload = buf[10:]
+	}
+}
+
+func (n *qNode) String() string {
+	now := Now()
+	return fmt.Sprintf("type=%s seq=%d scnt=%d sndtime~=%d,%d miss=%d",
+		packetTypeNames[n.flag], n.seq, n.scnt, n.sent-now, n.sent_1-now, n.miss)
+}
+
+func maxI64(a, b int64) int64 {
+	if a >= b {
+		return a
+	} else {
+		return b
+	}
+}
+
+func maxU32(a, b uint32) uint32 {
+	if a >= b {
+		return a
+	} else {
+		return b
+	}
+}
+
+func minI64(a, b int64) int64 {
+	if a <= b {
+		return a
+	} else {
+		return b
+	}
+}
+
+func maxI32(a, b int32) int32 {
+	if a >= b {
+		return a
+	} else {
+		return b
+	}
+}
+
+func minI32(a, b int32) int32 {
+	if a <= b {
+		return a
+	} else {
+		return b
+	}
+}