250 lines
6.7 KiB
Lua
250 lines
6.7 KiB
Lua
--
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-- pcap.lua: libpcap file format
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--
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-- Copyright (c) 2017, Přemysl Janouch <p.janouch@gmail.com>
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--
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-- Permission to use, copy, modify, and/or distribute this software for any
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-- purpose with or without fee is hereby granted, provided that the above
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-- copyright notice and this permission notice appear in all copies.
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--
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-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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-- WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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-- MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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-- SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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-- WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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-- OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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-- CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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--
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local detect = function (c)
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local magic = c:u32 ()
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return magic == 0xa1b2c3d4 or magic == 0xd4c3b2a1
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end
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local detect_ng = function (c)
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local magic = c (9):u32 ()
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return c:u32 () == 0x0a0d0d0a
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and (magic == 0x1a2b3c4d or magic == 0x4d3c2b1a)
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end
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-- Specified in http://www.tcpdump.org/linktypes.html
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local link_types = {
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[0] = "NULL",
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[1] = "ETHERNET",
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[3] = "AX25",
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[6] = "IEEE802_5",
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[7] = "ARCNET_BSD",
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[8] = "SLIP",
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[9] = "PPP",
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[10] = "FDDI",
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[50] = "PPP_HDLC",
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[51] = "PPP_ETHER",
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[100] = "ATM_RFC1483",
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[101] = "RAW",
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[104] = "C_HDLC",
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[105] = "IEEE802_11",
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[107] = "FRELAY",
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[108] = "LOOP",
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[113] = "LINUX_SLL",
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[114] = "LTALK",
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[117] = "PFLOG",
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[119] = "IEEE802_11_PRISM",
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[122] = "IP_OVER_FC",
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[123] = "SUNATM",
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[127] = "IEEE802_11_RADIOTAP",
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[129] = "ARCNET_LINUX",
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[138] = "APPLE_IP_OVER_IEEE1394",
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[139] = "MTP2_WITH_PHDR",
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[140] = "MTP2",
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[141] = "MTP3",
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[142] = "SCCP",
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[143] = "DOCSIS",
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[144] = "LINUX_IRDA",
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[147] = "USER0",
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[148] = "USER1",
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[149] = "USER2",
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[150] = "USER3",
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[151] = "USER4",
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[152] = "USER5",
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[153] = "USER6",
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[154] = "USER7",
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[155] = "USER8",
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[156] = "USER9",
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[157] = "USER10",
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[158] = "USER11",
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[159] = "USER12",
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[160] = "USER13",
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[161] = "USER14",
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[162] = "USER15",
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[163] = "IEEE802_11_AVS",
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[165] = "BACNET_MS_TP",
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[166] = "PPP_PPPD",
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[169] = "GPRS_LLC",
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[170] = "GPF_T",
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[171] = "GPF_F",
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[177] = "LINUX_LAPD",
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[187] = "BLUETOOTH_HCI_H4",
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[189] = "USB_LINUX",
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[192] = "PPI",
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[195] = "IEEE802_15_4",
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[196] = "SITA",
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[197] = "ERF",
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[201] = "BLUETOOTH_HCI_H4_WITH_PHDR",
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[202] = "AX25_KISS",
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[203] = "LAPD",
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[204] = "PPP_WITH_DIR",
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[205] = "C_HDLC_WITH_DIR",
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[206] = "FRELAY_WITH_DIR",
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[209] = "IPMB_LINUX",
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[215] = "IEEE802_15_4_NONASK_PHY",
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[220] = "USB_LINUX_MMAPPED",
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[224] = "FC_2",
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[225] = "FC_2_WITH_FRAME_DELIMS",
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[226] = "IPNET",
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[227] = "CAN_SOCKETCAN",
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[228] = "IPV4",
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[229] = "IPV6",
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[230] = "IEEE802_15_4_NOFCS",
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[231] = "DBUS",
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[235] = "DVB_CI",
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[236] = "MUX27010",
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[237] = "STANAG_5066_D_PDU",
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[239] = "NFLOG",
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[240] = "NETANALYZER",
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[241] = "NETANALYZER_TRANSPARENT",
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[242] = "IPOIB",
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[243] = "MPEG_2_TS",
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[244] = "NG40",
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[245] = "NFC_LLCP",
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[247] = "INFINIBAND",
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[248] = "SCTP",
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[249] = "USBPCAP",
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[250] = "RTAC_SERIAL",
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[251] = "BLUETOOTH_LE_LL",
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[253] = "NETLINK",
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[254] = "BLUETOOTH_LINUX_MONITOR",
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[255] = "BLUETOOTH_BREDR_BB",
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[256] = "BLUETOOTH_LE_LL_WITH_PHDR",
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[257] = "PROFIBUS_DL",
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[258] = "PKTAP",
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[259] = "EPON",
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[260] = "IPMI_HPM_2",
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[261] = "ZWAVE_R1_R2",
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[262] = "ZWAVE_R3",
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[263] = "WATTSTOPPER_DLM",
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[264] = "ISO_14443",
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[265] = "RDS",
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[266] = "USB_DARWIN"
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}
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-- As described by https://wiki.wireshark.org/Development/LibpcapFileFormat
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local decode = function (c)
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if not detect (c ()) then error ("not a PCAP file") end
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c.endianity = "le"
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c:u32 ("PCAP magic: %s", function (u32)
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if u32 == 0xa1b2c3d4 then return "little-endian" end
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c.endianity = "be"
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return "big-endian"
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end)
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local p, vmajor, vminor = c.position, c:u16 (), c:u16 ()
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c (p, c.position - 1):mark ("PCAP version: %d.%d", vmajor, vminor)
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local zone = c:i32 ("UTC to local TZ correction: %d seconds")
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local sigfigs = c:u32 ("timestamp accuracy")
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local snaplen = c:u32 ("max. length of captured packets")
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local network = c:u32 ("data link type: %s", function (u32)
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name = link_types[u32]
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if name then return name end
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return "unknown: %d", u32
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end)
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local i = 0
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while not c.eof do
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c (c.position, c.position + 23):mark ("PCAP record %d header", i)
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i = i + 1
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local p, ts_sec, ts_usec = p, c:u32 (), c:u32 ()
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c (p, c.position - 1):mark ("timestamp: %s.%06d",
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os.date ("!%F %T", ts_sec + zonen), ts_usec)
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local incl_len = c:u32 ("included record length")
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local orig_len = c:u32 ("original record length")
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local p = c.position
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c.position = c.position + incl_len
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-- TODO: also decode record contents as per the huge table
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c (p, c.position - 1):mark ("PCAP record %d data", i)
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end
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end
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hex.register { type="pcap", detect=detect, decode=decode }
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local block_types = {
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[0x0a0d0d0a] = "Section Header Block",
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[0x00000001] = "Interface Description Block",
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[0x00000003] = "Simple Packet Block",
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[0x00000004] = "Name Resolution Block",
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[0x00000005] = "Interface Statistics Block",
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[0x00000006] = "Enhanced Packet Block",
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[0x00000BAD] = "Custom Block",
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[0x40000BAD] = "Custom Block"
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}
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local decode_shb = function (c)
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local magic = c:u32 ()
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local p, vmajor, vminor = c.position, c:u16 (), c:u16 ()
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c (p, c.position - 1):mark ("PCAPNG version: %d.%d", vmajor, vminor)
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-- XXX: what exactly does section_len mean?
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local section_len = c:u64 ("section length: %d")
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while not c.eof do
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-- TODO: decode the meaning of options as well
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local type = c:u16 ("option type: %d")
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local length = c:u16 ("option length: %d")
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local p = c.position
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c.position = c.position + length + (-length & 3)
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c (p, c.position - 1):mark ("option value")
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end
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end
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local block_decoders = {
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-- TODO: also decode other types of blocks
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[0x0a0d0d0a] = decode_shb
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}
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-- As described by https://github.com/pcapng/pcapng
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local decode_ng = function (c)
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assert (c.position == 1)
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if not detect_ng (c ()) then error ("not a PCAPNG file") end
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c.endianity = "le"
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c (9):u32 ("byte-order magic: %s", function (u32)
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if u32 == 0x1a2b3c4d then return "little-endian" end
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c.endianity = "be"
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return "big-endian"
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end)
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while not c.eof do
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local block_start = c.position
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local block_type = c:u32 ("PCAPNG block type: %s", function (u32)
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local name = block_types[u32]
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if name then return name end
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return "unknown: %d", u32
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end)
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local block_len = c:u32 ("PCAPNG block length: %d")
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local data_start = c.position
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c.position = block_start + block_len - 4
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local decoder = block_decoders[block_type]
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if decoder then decoder (c (data_start, c.position - 1)) end
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c:u32 ("PCAPNG trailing block length: %d")
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end
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end
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hex.register { type="pcapng", detect=detect_ng, decode=decode_ng }
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