def _dissect(self, buf):
# Needed by _parse_flags()
self.present_flags = unpack_I(buf[4:8])[0]
#logger.debug("Flags: 0x%X" % flags)
pos_end = len(buf)
# Check for FSC, needs to be skipped for upper layers
if self.present_flags & FLAGS_MASK == FLAGS_MASK:
#logger.debug("Flags mask matched")
flags_off = 8
# TSFT present -> Flags values are after TSFT value
if self.present_flags & TSFT_MASK == TSFT_MASK:
flags_off = 8 + 8
if buf[flags_off] & 0x10 != 0:
#logger.debug("FCS found")
self._fcs = buf[-4:]
pos_end = -4
hdr_len = unpack_H_le(buf[2:4])[0]
#logger.debug("Bytes for flags (%d): %s" % (hdr_len, buf[8: hdr_len]))
self._init_triggerlist("flags", buf[8: hdr_len], self._parse_flags)
#logger.debug("rtap bytes:=%r" % buf[:hdr_len])
# now we got the correct header length
self._init_handler(RTAP_TYPE_80211, buf[hdr_len: pos_end])
#logger.debug("Adding %d flags" % len(self.flags))
return hdr_len
def extract_certificates(self):
"""
Extracts certificates from a Handshake packet
Workflow:
find 1# cert segment(SSL.get_cert_length()) -> collect/assemble until
cert length collected -> create SSL(tcp_bytes) -> ssl.handshake.extract_certs()
return -- [cert1, cert2, ...]
"""
ret = []
if self.type != HNDS_CERTIFICATE:
logger.warning("not a certificate handshake: %r", self)
return ret
bts_body = self.body_bytes
certs_len = self.len_i - 3
#logger.debug("total cert length: %d", certs_len)
# skip total cert length
off = 3
while off < certs_len:
cert_len = unpack_I(b"\x00" + bts_body[off:off + 3])[0]
#logger.debug("cert length: %d", cert_len)
cert_bytes = bts_body[off + 3:off + 3 + cert_len]
off += 3 + cert_len
ret.append(cert_bytes)
return ret
def count_and_dissect_tlvs(buf):
"""
Count and dissect TLVs. Return length of LLDP layer
buf -- buffer to dissect
return -- parsed_bytes_total, [(clz, bts), ...]
"""
shift = 0
tlv_type, tlv_len = 1, 1
clz_bts_list = []
while (tlv_type | tlv_len) != 0:
type_and_len = unpack_H(buf[shift:shift + TLV_HEADER_LEN])[0]
# get tlv length and type
tlv_type = (type_and_len & TYPE_MASK) >> LENGTH_FIELD_BITS
tlv_len = type_and_len & LENGTH_MASK
if tlv_type != ORG_SPEC_TYPE:
clz = LLDP_TLV_CLS.get(tlv_type, LLDPGeneric)
else:
oui_subtype = unpack_I(
buf[shift + TLV_HEADER_LEN:shift + ORG_SPEC_HEADER_LEN +
TLV_HEADER_LEN])[0]
oui = (oui_subtype & OUI_MASK) >> SUBTYPE_LEN_BITS
subtype = oui_subtype & SUBTYPE_MASK
clz = LLDP_ORG_SPEC_TLV_CLS.get((oui, subtype), LLDPOrgSpecGeneric)
# get body bytes
tlv_body = buf[shift:tlv_len + shift + TLV_HEADER_LEN]
# update shift to begin of next TLV (TLV_HEADER_LEN:2 + content:x)
shift += TLV_HEADER_LEN + tlv_len
clz_bts_list.append((clz, tlv_body))
return shift, clz_bts_list
def _dissect(self, buf):
# parse chunks
chunks = []
off = 12
blen = len(buf)
# logger.debug("SCTP: parsing chunks")
chunktype = -1
# TODO: use lazy dissect, possible?
while off + 4 < blen:
dlen = unpack_H(buf[off + 2:off + 4])[0]
# check for padding (this should be a data chunk)
if off + dlen < blen:
self.padding = buf[off + dlen:]
# logger.debug("found padding: %s" % self.padding)
chunk = Chunk(buf[off:off + dlen])
# logger.debug("SCTP: Chunk; %s " % chunk)
chunks.append(chunk)
# get payload chunktype from DATA chunks
if chunk.type == 0:
chunktype = unpack_I(buf[off + chunk.header_len + 8:off +
chunk.header_len + 8 + 4])[0]
# logger.debug("got DATA chunk, chunktype: %d" % chunktype)
# remove data from chunk: use bytes for handler
chunk.body_bytes = b""
off += len(chunk)
# assume DATA is the last chunk
break
off += dlen
self.chunks.extend(chunks)
chunktype = unpack_H(buf[2:4])[0]
self._init_handler(chunktype, buf[off:-len(self.padding)])
return off
def _dissect(self, buf):
flags = self._present_flags = unpack_I(buf[4:8])[0]
pos_end = len(buf)
if flags & FLAGS_MASK == FLAGS_MASK:
off = 0
if flags & TSFT_MASK == TSFT_MASK:
off = 8
if buf[off] & 0x10 != 0:
#logger.debug("fcs found")
self._fcs = buf[-4:]
pos_end = -4
hdr_len = unpack_H_le(buf[2:4])[0]
#logger.debug("hdr length is: %d" % hdr_len)
self._init_triggerlist("flags", buf[8:hdr_len], self._parse_flags)
#logger.debug("rtap bytes:=%r" % buf[:hdr_len])
# now we got the correct header length
self._init_handler(RTAP_TYPE_80211, buf[hdr_len:pos_end])
#logger.debug(adding %d flags" % len(self.flags))
return hdr_len
def __get_crcinit_rev_int(self):
return unpack_I(b"\x00" + self.crcinit_rev)[0]