// getNextBufPtrLocked is shared code for ReadPacketData and
// ZeroCopyReadPacketData.
func (p *Handle) getNextBufPtrLocked(ci *gopacket.CaptureInfo) error {
if p.cptr == nil {
return io.EOF
}
var result NextError
for {
result = NextError(C.pcap_next_ex(p.cptr, &p.pkthdr, &p.buf_ptr))
if p.blockForever && result == NextErrorTimeoutExpired {
continue
}
break
}
if result != NextErrorOk {
if result == NextErrorNoMorePackets {
return io.EOF
} else {
return result
}
}
ci.Timestamp = time.Unix(int64(p.pkthdr.ts.tv_sec),
int64(p.pkthdr.ts.tv_usec)*1000) // convert micros to nanos
ci.CaptureLength = int(p.pkthdr.caplen)
ci.Length = int(p.pkthdr.len)
return nil
}
// Capture a single packet from the packet source. This will block until a
// packet is received.
func (h *Handle) Capture() ([]byte, error) {
var buf *C.u_char
var pkt_hdr *C.struct_pcap_pkthdr
for {
err := C.pcap_next_ex(h.pcap, &pkt_hdr, &buf)
switch err {
case -2:
return nil, nil
case -1:
return nil, fmt.Errorf(
"Could not read packet: %s", h.get_error(),
)
case 0:
continue
case 1:
return C.GoBytes(unsafe.Pointer(buf),
C.int(pkt_hdr.len)), nil
}
}
return nil, fmt.Errorf("WTF")
}
func (p *Pcap) NextEx() (pkt *Packet, result int32) {
var pkthdr_ptr *_Ctype_struct_pcap_pkthdr
var pkthdr _Ctype_struct_pcap_pkthdr
var buf_ptr *_Ctypedef_u_char
var buf unsafe.Pointer
result = int32(C.pcap_next_ex(p.cptr, &pkthdr_ptr, &buf_ptr))
buf = unsafe.Pointer(buf_ptr)
pkthdr = *pkthdr_ptr
if nil == buf {
pkt = nil
return
}
pkt = new(Packet)
pkt.Time.Sec = int32(pkthdr.ts.tv_sec)
pkt.Time.Usec = int32(pkthdr.ts.tv_usec)
pkt.Caplen = uint32(pkthdr.caplen)
pkt.Len = uint32(pkthdr.len)
pkt.Data = make([]byte, pkthdr.caplen)
for i := uint32(0); i < pkt.Caplen; i++ {
pkt.Data[i] = *(*byte)(unsafe.Pointer(uintptr(buf) + uintptr(i)))
}
return
}
func (p *Pcap) Next() (*Packet, os.Error) {
var header *C.struct_pcap_pkthdr
var buf *C.u_char
switch C.pcap_next_ex(p.cptr, &header, &buf) {
case 0:
return nil, os.NewError("read time out")
case -1:
return nil, os.NewError(p.Geterror())
case -2:
return nil, os.NewError("savefile eof")
}
ret := new(Packet)
ret.Time.Sec = int32(header.ts.tv_sec)
ret.Time.Usec = int32(header.ts.tv_usec)
ret.Caplen = uint32(header.caplen)
ret.Len = uint32(header.len)
ret.Data = make([]byte, header.caplen)
if header.caplen > 0 {
C.memcpy(unsafe.Pointer(&ret.Data[0]), unsafe.Pointer(buf), C.size_t(header.caplen))
}
return ret, nil
}
func (p *Pcap) Next() (*Packet, error) {
var packet Packet
rc := C.pcap_next_ex(p.pcap, &packet.header, &packet.data)
if rc == 1 {
return &packet, nil
} else if rc == 0 || rc == -2 {
return nil, nil
}
return nil, errors.New(p.GetErr())
}
// NextEx reads the next packet and returns a success/failure indication:
//
// 1 the packet was read without problems
// 0 packets are being read from a live capture, and the timeout expired
// -1 an error occurred while reading the packet
// -2 packets are being read from a file, and there are no more packets to read
func (p *Pcap) NextEx() (*pkt.Packet, int32) {
var pkthdr_ptr *C.struct_pcap_pkthdr
var buf_ptr *C.u_char
res := int32(C.pcap_next_ex(p.cptr, &pkthdr_ptr, &buf_ptr))
if res == 1 {
p.m.Lock()
packet := pkt.NewPacket(unsafe.Pointer(pkthdr_ptr), unsafe.Pointer(buf_ptr))
p.m.Unlock()
p.pktCnt++
return packet, res
}
return nil, res
}
// getNextBufPtrLocked is shared code for ReadPacketData and
// ZeroCopyReadPacketData.
func (p *Handle) getNextBufPtrLocked(ci *gopacket.CaptureInfo) error {
p.activate.Do(p.activation)
result := NextError(C.pcap_next_ex(p.cptr, &p.pkthdr, &p.buf_ptr))
if result != NextErrorOk {
if result == NextErrorNoMorePackets {
return io.EOF
} else {
return result
}
}
ci.Timestamp = time.Unix(int64(p.pkthdr.ts.tv_sec),
int64(p.pkthdr.ts.tv_usec)*1000) // convert micros to nanos
ci.CaptureLength = int(p.pkthdr.caplen)
ci.Length = int(p.pkthdr.len)
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)
}
}
}