// Pack packets into their binary form. This will stack the packets before
// encoding them (see the Compose() method) and also calculate the checksums.
func Pack(pkts ...packet.Packet) ([]byte, error) {
var buf packet.Buffer
base_pkt, err := Compose(pkts...)
if err != nil {
return nil, err
}
tot_len := int(base_pkt.GetLength())
buf.Init(make([]byte, tot_len))
for i := len(pkts) - 1; i >= 0; i-- {
cur_pkt := pkts[i]
cur_len := int(cur_pkt.GetLength())
buf.SetOffset(tot_len - cur_len)
buf.NewLayer()
err := cur_pkt.Pack(&buf)
if err != nil {
return nil, err
}
}
buf.SetOffset(0)
return buf.Bytes(), nil
}
func (p *Packet) Unpack(buf *packet.Buffer) error {
buf.ReadN(&p.DSAP)
buf.ReadN(&p.SSAP)
if buf.Bytes()[:1][0]&0x1 == 0 ||
buf.Bytes()[:1][0]&0x3 == 0x1 {
buf.ReadN(&p.Control)
} else {
var ctrl uint8
buf.ReadN(&ctrl)
p.Control = uint16(ctrl)
}
return nil
}