PCAP (named after libpcap / winpcap) is a popular format for saving network traffic grabbed by network sniffers. It is typically produced by tools like tcpdump or Wireshark.
This page hosts a formal specification of .pcap / .pcapdump file format using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
All parsing code for Python generated by Kaitai Struct depends on the Python runtime library. You have to install it before you can parse data.
The Python runtime library can be installed from PyPI:
python3 -m pip install kaitaistructParse a local file and get structure in memory:
data = Pcap.from_file("path/to/local/file.pcap")
Or parse structure from a bytes:
from kaitaistruct import KaitaiStream, BytesIO
raw = b"\x00\x01\x02..."
data = Pcap(KaitaiStream(BytesIO(raw)))
After that, one can get various attributes from the structure by invoking getter methods like:
data.hdr # => get hdr
# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
import kaitaistruct
from kaitaistruct import KaitaiStruct, KaitaiStream, BytesIO
from enum import Enum
if getattr(kaitaistruct, 'API_VERSION', (0, 9)) < (0, 9):
raise Exception("Incompatible Kaitai Struct Python API: 0.9 or later is required, but you have %s" % (kaitaistruct.__version__))
import packet_ppi
import ethernet_frame
class Pcap(KaitaiStruct):
"""PCAP (named after libpcap / winpcap) is a popular format for saving
network traffic grabbed by network sniffers. It is typically
produced by tools like [tcpdump](https://www.tcpdump.org/) or
[Wireshark](https://www.wireshark.org/).
.. seealso::
Source - https://wiki.wireshark.org/Development/LibpcapFileFormat
"""
class Linktype(Enum):
null_linktype = 0
ethernet = 1
exp_ethernet = 2
ax25 = 3
pronet = 4
chaos = 5
ieee802_5 = 6
arcnet_bsd = 7
slip = 8
ppp = 9
fddi = 10
redback_smartedge = 32
ppp_hdlc = 50
ppp_ether = 51
symantec_firewall = 99
atm_rfc1483 = 100
raw = 101
c_hdlc = 104
ieee802_11 = 105
atm_clip = 106
frelay = 107
loop = 108
enc = 109
netbsd_hdlc = 112
linux_sll = 113
ltalk = 114
econet = 115
ipfilter = 116
pflog = 117
cisco_ios = 118
ieee802_11_prism = 119
aironet_header = 120
ip_over_fc = 122
sunatm = 123
rio = 124
pci_exp = 125
aurora = 126
ieee802_11_radiotap = 127
tzsp = 128
arcnet_linux = 129
juniper_mlppp = 130
juniper_mlfr = 131
juniper_es = 132
juniper_ggsn = 133
juniper_mfr = 134
juniper_atm2 = 135
juniper_services = 136
juniper_atm1 = 137
apple_ip_over_ieee1394 = 138
mtp2_with_phdr = 139
mtp2 = 140
mtp3 = 141
sccp = 142
docsis = 143
linux_irda = 144
ibm_sp = 145
ibm_sn = 146
user0 = 147
user1 = 148
user2 = 149
user3 = 150
user4 = 151
user5 = 152
user6 = 153
user7 = 154
user8 = 155
user9 = 156
user10 = 157
user11 = 158
user12 = 159
user13 = 160
user14 = 161
user15 = 162
ieee802_11_avs = 163
juniper_monitor = 164
bacnet_ms_tp = 165
ppp_pppd = 166
juniper_pppoe = 167
juniper_pppoe_atm = 168
gprs_llc = 169
gpf_t = 170
gpf_f = 171
gcom_t1e1 = 172
gcom_serial = 173
juniper_pic_peer = 174
erf_eth = 175
erf_pos = 176
linux_lapd = 177
juniper_ether = 178
juniper_ppp = 179
juniper_frelay = 180
juniper_chdlc = 181
mfr = 182
juniper_vp = 183
a429 = 184
a653_icm = 185
usb_freebsd = 186
bluetooth_hci_h4 = 187
ieee802_16_mac_cps = 188
usb_linux = 189
can20b = 190
ieee802_15_4_linux = 191
ppi = 192
ieee802_16_mac_cps_radio = 193
juniper_ism = 194
ieee802_15_4_withfcs = 195
sita = 196
erf = 197
raif1 = 198
ipmb_kontron = 199
juniper_st = 200
bluetooth_hci_h4_with_phdr = 201
ax25_kiss = 202
lapd = 203
ppp_with_dir = 204
c_hdlc_with_dir = 205
frelay_with_dir = 206
lapb_with_dir = 207
ipmb_linux = 209
flexray = 210
most = 211
lin = 212
x2e_serial = 213
x2e_xoraya = 214
ieee802_15_4_nonask_phy = 215
linux_evdev = 216
gsmtap_um = 217
gsmtap_abis = 218
mpls = 219
usb_linux_mmapped = 220
dect = 221
aos = 222
wihart = 223
fc_2 = 224
fc_2_with_frame_delims = 225
ipnet = 226
can_socketcan = 227
ipv4 = 228
ipv6 = 229
ieee802_15_4_nofcs = 230
dbus = 231
juniper_vs = 232
juniper_srx_e2e = 233
juniper_fibrechannel = 234
dvb_ci = 235
mux27010 = 236
stanag_5066_d_pdu = 237
juniper_atm_cemic = 238
nflog = 239
netanalyzer = 240
netanalyzer_transparent = 241
ipoib = 242
mpeg_2_ts = 243
ng40 = 244
nfc_llcp = 245
pfsync = 246
infiniband = 247
sctp = 248
usbpcap = 249
rtac_serial = 250
bluetooth_le_ll = 251
wireshark_upper_pdu = 252
netlink = 253
bluetooth_linux_monitor = 254
bluetooth_bredr_bb = 255
bluetooth_le_ll_with_phdr = 256
profibus_dl = 257
pktap = 258
epon = 259
ipmi_hpm_2 = 260
zwave_r1_r2 = 261
zwave_r3 = 262
wattstopper_dlm = 263
iso_14443 = 264
rds = 265
usb_darwin = 266
openflow = 267
sdlc = 268
ti_lln_sniffer = 269
loratap = 270
vsock = 271
nordic_ble = 272
docsis31_xra31 = 273
ethernet_mpacket = 274
displayport_aux = 275
linux_sll2 = 276
sercos_monitor = 277
openvizsla = 278
ebhscr = 279
vpp_dispatch = 280
dsa_tag_brcm = 281
dsa_tag_brcm_prepend = 282
ieee802_15_4_tap = 283
dsa_tag_dsa = 284
dsa_tag_edsa = 285
elee = 286
zwave_serial = 287
usb_2_0 = 288
atsc_alp = 289
etw = 290
netanalyzer_ng = 291
zboss_ncp = 292
usb_2_0_low_speed = 293
usb_2_0_full_speed = 294
usb_2_0_high_speed = 295
auerswald_log = 296
zwave_tap = 297
silabs_debug_channel = 298
fira_uci = 299
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.hdr = Pcap.Header(self._io, self, self._root)
self.packets = []
i = 0
while not self._io.is_eof():
self.packets.append(Pcap.Packet(self._io, self, self._root))
i += 1
class Header(KaitaiStruct):
"""
.. seealso::
Source - https://wiki.wireshark.org/Development/LibpcapFileFormat#Global_Header
"""
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.magic_number = self._io.read_bytes(4)
if not self.magic_number == b"\xD4\xC3\xB2\xA1":
raise kaitaistruct.ValidationNotEqualError(b"\xD4\xC3\xB2\xA1", self.magic_number, self._io, u"/types/header/seq/0")
self.version_major = self._io.read_u2le()
if not self.version_major == 2:
raise kaitaistruct.ValidationNotEqualError(2, self.version_major, self._io, u"/types/header/seq/1")
self.version_minor = self._io.read_u2le()
self.thiszone = self._io.read_s4le()
self.sigfigs = self._io.read_u4le()
self.snaplen = self._io.read_u4le()
self.network = KaitaiStream.resolve_enum(Pcap.Linktype, self._io.read_u4le())
class Packet(KaitaiStruct):
"""
.. seealso::
Source - https://wiki.wireshark.org/Development/LibpcapFileFormat#Record_.28Packet.29_Header
"""
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.ts_sec = self._io.read_u4le()
self.ts_usec = self._io.read_u4le()
self.incl_len = self._io.read_u4le()
self.orig_len = self._io.read_u4le()
_on = self._root.hdr.network
if _on == Pcap.Linktype.ppi:
self._raw_body = self._io.read_bytes((self.incl_len if self.incl_len < self._root.hdr.snaplen else self._root.hdr.snaplen))
_io__raw_body = KaitaiStream(BytesIO(self._raw_body))
self.body = packet_ppi.PacketPpi(_io__raw_body)
elif _on == Pcap.Linktype.ethernet:
self._raw_body = self._io.read_bytes((self.incl_len if self.incl_len < self._root.hdr.snaplen else self._root.hdr.snaplen))
_io__raw_body = KaitaiStream(BytesIO(self._raw_body))
self.body = ethernet_frame.EthernetFrame(_io__raw_body)
else:
self.body = self._io.read_bytes((self.incl_len if self.incl_len < self._root.hdr.snaplen else self._root.hdr.snaplen))