// NewPacket creates a new cattp packet based on an existing pcap packet. Error is returned if
// the pcap packet is not a cattp packet.
func NewPacket(p *pcap.Packet) (ret *Packet, err error) {
p.Decode()
ret = &Packet{}
//find lower header
for _, h := range p.Headers {
if ih, ok := h.(*pcap.Iphdr); ok {
ret.ip = ih
}
if uh, ok := h.(*pcap.Udphdr); ok {
ret.udp = uh
}
}
// assert whether is udp datagram
if ret.ip == nil || ret.udp == nil {
return nil, fmt.Errorf("Not a udp packet.")
}
//Parse the cattp header
hdr, err := NewHeader(p.Payload)
if err != nil {
return
}
ret.Header = *hdr
return
}
func (s SourceMap) process(pkt *pcap.Packet) {
pkt.Decode()
if len(pkt.Headers) >= 2 {
if addr, ok := pkt.Headers[0].(addrHdr); ok {
s.route(pkt, &addr)
}
}
}