// SetDirection sets the direction for which packets will be captured.
func (p *Handle) SetDirection(direction Direction) error {
if direction != DirectionIn && direction != DirectionOut && direction != DirectionInOut {
return fmt.Errorf("Invalid direction: %v", direction)
}
if status := C.pcap_setdirection(p.cptr, (C.pcap_direction_t)(direction)); status < 0 {
return statusError(status)
}
return nil
}
func (p *Pcap) SetDirection(direction string) (err error) {
var pcap_direction C.pcap_direction_t
if direction == "in" {
pcap_direction = C.PCAP_D_IN
} else if direction == "out" {
pcap_direction = C.PCAP_D_OUT
} else {
pcap_direction = C.PCAP_D_INOUT
}
if -1 == C.pcap_setdirection(p.cptr, pcap_direction) {
return p.Geterror()
}
return nil
}
func main() {
var errbuf = (*C.char)(C.malloc(C.PCAP_ERRBUF_SIZE))
defer C.free(unsafe.Pointer(errbuf))
var source = C.CString("any")
defer C.free(unsafe.Pointer(source))
pcap_handle := C.pcap_create(source, errbuf)
if pcap_handle == nil {
panic("pcap_handle")
}
C.pcap_set_buffer_size(pcap_handle, 2*1024*1024)
C.pcap_set_promisc(pcap_handle, 1)
C.pcap_set_snaplen(pcap_handle, 512) // more than enough to recognize a WOL packet
C.pcap_setdirection(pcap_handle, C.PCAP_D_IN)
if C.pcap_activate(pcap_handle) != 0 {
panic(C.GoString(C.pcap_geterr(pcap_handle)))
}
var bpf_program C.struct_bpf_program
if C.pcap_compile(pcap_handle, &bpf_program, pcap_filter, 0, 0) != 0 {
panic(C.GoString(C.pcap_geterr(pcap_handle)))
}
if C.pcap_setfilter(pcap_handle, &bpf_program) != 0 {
panic(C.GoString(C.pcap_geterr(pcap_handle)))
}
for {
var pkt_header *C.struct_pcap_pkthdr
var pkt_data *C.u_char
if C.pcap_next_ex(pcap_handle, &pkt_header, &pkt_data) < 0 {
panic(C.GoString(C.pcap_geterr(pcap_handle)))
}
if pkt_data == nil {
continue
}
data := make([]byte, pkt_header.caplen)
copy(data, (*(*[10000000]byte)(unsafe.Pointer(pkt_data)))[0:])
from_mac, to_mac := checkwol(data)
if from_mac != "" {
fmt.Printf("%v: %v sends WOL to %v\n", time.Now(), from_mac, to_mac)
}
}
}