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(Using sed : sed -i '/^ \* \$Id\$/,+1 d') Fix manually some typo (in export_object_dicom.c and crc16-plain.c) Change-Id: I4c1ae68d1c4afeace8cb195b53c715cf9e1227a8 Reviewed-on: https://code.wireshark.org/review/497 Reviewed-by: Anders Broman <a.broman58@gmail.com>
499 lines
17 KiB
C
499 lines
17 KiB
C
/* packet-null.c
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* Routines for null packet disassembly
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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*
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* This file created by Mike Hall <mlh@io.com>
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* Copyright 1998
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "config.h"
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#include <glib.h>
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#include <string.h>
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#include <epan/packet.h>
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#include "packet-null.h"
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#include <epan/atalk-utils.h>
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#include <epan/prefs.h>
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#include "packet-ip.h"
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#include "packet-ipv6.h"
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#include "packet-ipx.h"
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#include "packet-osi.h"
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#include "packet-ppp.h"
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#include <epan/etypes.h>
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#include <epan/aftypes.h>
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#include <wiretap/wtap.h>
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void proto_register_null(void);
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void proto_reg_handoff_null(void);
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static dissector_table_t null_dissector_table;
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static dissector_table_t ethertype_dissector_table;
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/* protocols and header fields */
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static int proto_null = -1;
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static int hf_null_etype = -1;
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static int hf_null_family = -1;
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static gint ett_null = -1;
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/* Null/loopback structs and definitions */
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/* Family values. */
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static const value_string family_vals[] = {
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{BSD_AF_INET, "IP" },
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{BSD_AF_ISO, "OSI" },
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{BSD_AF_APPLETALK, "Appletalk" },
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{BSD_AF_IPX, "Netware IPX/SPX"},
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{BSD_AF_INET6_BSD, "IPv6" },
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{BSD_AF_INET6_FREEBSD, "IPv6" },
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{BSD_AF_INET6_DARWIN, "IPv6" },
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{0, NULL }
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};
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static dissector_handle_t ppp_hdlc_handle;
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static dissector_handle_t data_handle;
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void
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capture_null( const guchar *pd, int len, packet_counts *ld )
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{
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guint32 null_header;
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/*
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* BSD drivers that use DLT_NULL - including the FreeBSD 3.2 ISDN-for-BSD
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* drivers, as well as the 4.4-Lite and FreeBSD loopback drivers -
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* stuff the AF_ value for the protocol, in *host* byte order, in the
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* first four bytes. (BSD drivers that use DLT_LOOP, such as recent
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* OpenBSD loopback drivers, stuff it in *network* byte order in the
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* first four bytes.)
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*
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* However, the IRIX and UNICOS/mp snoop socket mechanism supplies,
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* on loopback devices, a 4-byte header that has a 2 byte (big-endian)
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* AF_ value and 2 bytes of 0, so it's
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*
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* 0000AAAA
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*
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* when read on a little-endian machine and
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*
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* AAAA0000
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*
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* when read on a big-endian machine. The current CVS version of libpcap
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* compensates for this by converting it to standard 4-byte format before
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* processing the packet, but snoop captures from IRIX or UNICOS/mp
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* have the 2-byte+2-byte header, as might tcpdump or libpcap captures
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* with older versions of libpcap.
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*
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* AF_ values are small integers, and probably fit in 8 bits (current
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* values on the BSDs do), and have their upper 24 bits zero.
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* This means that, in practice, if you look at the header as a 32-bit
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* integer in host byte order:
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*
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* on a little-endian machine:
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*
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* a little-endian DLT_NULL header looks like
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*
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* 000000AA
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*
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* a big-endian DLT_NULL header, or a DLT_LOOP header, looks
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* like
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*
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* AA000000
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*
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* an IRIX or UNICOS/mp DLT_NULL header looks like
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*
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* 0000AA00
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*
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* on a big-endian machine:
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*
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* a big-endian DLT_NULL header, or a DLT_LOOP header, looks
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* like
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*
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* 000000AA
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*
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* a little-endian DLT_NULL header looks like
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*
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* AA000000
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*
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* an IRIX or UNICOS/mp DLT_NULL header looks like
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*
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* 00AA0000
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*
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* However, according to Gerald Combs, a FreeBSD ISDN PPP dump that
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* Andreas Klemm sent to wireshark-dev has a packet type of DLT_NULL,
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* and the family bits look like PPP's protocol field. (Was this an
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* older, or different, ISDN driver?) Looking at what appears to be
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* that capture file, it appears that it's using PPP in HDLC framing,
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* RFC 1549, wherein the first two octets of the frame are 0xFF
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* (address) and 0x03 (control), so the header bytes are, in order:
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*
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* 0xFF
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* 0x03
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* high-order byte of a PPP protocol field
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* low-order byte of a PPP protocol field
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*
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* If we treat that as a 32-bit host-byte-order value, it looks like
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*
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* PPPP03FF
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*
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* where PPPP is a byte-swapped PPP protocol type if we read it on
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* a little-endian machine and
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*
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* FF03PPPP
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*
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* where PPPP is a PPP protocol type if we read it on a big-endian
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* machine. 0x0000 does not appear to be a valid PPP protocol type
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* value, so at least one of those hex digits is guaranteed not to
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* be 0.
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*
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* Old versions of libpcap for Linux used DLT_NULL for loopback devices,
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* but not any other devices. (Current versions use DLT_EN10MB for it.)
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* The Linux loopback driver puts an *Ethernet* header at the beginning
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* of loopback packets, with fake source and destination addresses and
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* the appropriate Ethernet type value; however, those older versions of
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* libpcap for Linux compensated for this by skipping the source and
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* destination MAC addresses, replacing them with 2 bytes of 0.
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* This means that if we're reading the capture on a little-endian
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* machine, the header, treated as a 32-bit integer, looks like
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*
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* EEEE0000
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*
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* where EEEE is a byte-swapped Ethernet type, and if we're reading it
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* on a big-endian machine, it looks like
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*
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* 0000EEEE
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*
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* where EEEE is an Ethernet type.
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*
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* If the first 2 bytes of the header are FF 03:
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*
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* it can't be a big-endian BSD DLT_NULL header, or a DLT_LOOP
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* header, as AF_ values are small so the first 2 bytes of the
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* header would be 0;
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*
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* it can't be a little-endian BSD DLT_NULL header, as the
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* resulting AF_ value would be >= 0x03FF, which is too big
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* for an AF_ value;
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*
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* it can't be an IRIX or UNICOS/mp DLT_NULL header, as the
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* resulting AF_ value with be 0x03FF.
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*
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* So the first thing we do is check the first two bytes of the
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* header; if it's FF 03, we treat the packet as a PPP frame.
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*
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* Otherwise, if the upper 16 bits are non-zero, either:
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*
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* it's a BSD DLT_NULL or DLT_LOOP header whose AF_ value
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* is not in our byte order;
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*
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* it's an IRIX or UNICOS/mp DLT_NULL header being read on
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* a big-endian machine;
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*
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* it's a Linux DLT_NULL header being read on a little-endian
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* machine.
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*
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* In all those cases except for the IRIX or UNICOS/mp DLT_NULL header,
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* we should byte-swap it (if it's a Linux DLT_NULL header, that'll
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* put the Ethernet type in the right byte order). In the case
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* of the IRIX or UNICOS/mp DLT_NULL header, we should just get
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* the upper 16 bits as an AF_ value.
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*
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* If it's a BSD DLT_NULL or DLT_LOOP header whose AF_ value is not
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* in our byte order, then the upper 2 hex digits would be non-zero
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* and the next 2 hex digits down would be zero, as AF_ values fit in
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* 8 bits, and the upper 2 hex digits are the *lower* 8 bits of the value.
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*
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* If it's an IRIX or UNICOS/mp DLT_NULL header, the upper 2 hex digits
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* would be zero and the next 2 hex digits down would be non-zero, as
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* the upper 16 bits are a big-endian AF_ value. Furthermore, the
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* next 2 hex digits down are likely to be < 0x60, as 0x60 is 96,
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* and, so far, we're far from requiring AF_ values that high.
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*
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* If it's a Linux DLT_NULL header, the third hex digit from the top
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* will be >= 6, as Ethernet types are >= 1536, or 0x0600, and
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* it's byte-swapped, so the second 2 hex digits from the top are
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* >= 0x60.
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*
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* So, if the upper 16 bits are non-zero:
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*
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* if the upper 2 hex digits are 0 and the next 2 hex digits are
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* in the range 0x00-0x5F, we treat it as a big-endian IRIX or
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* UNICOS/mp DLT_NULL header;
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*
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* otherwise, we byte-swap it and do the next stage.
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*
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* If the upper 16 bits are zero, either:
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*
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* it's a BSD DLT_NULLor DLT_LOOP header whose AF_ value is in
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* our byte order;
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*
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* it's an IRIX or UNICOS/mp DLT_NULL header being read on
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* a little-endian machine;
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*
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* it's a Linux DLT_NULL header being read on a big-endian
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* machine.
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*
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* In all of those cases except for the IRIX or UNICOS/mp DLT_NULL header,
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* we should *not* byte-swap it. In the case of the IRIX or UNICOS/mp
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* DLT_NULL header, we should extract the AF_ value and byte-swap it.
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*
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* If it's a BSD DLT_NULL or DLT_LOOP header whose AF_ value is
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* in our byte order, the upper 6 hex digits would all be zero.
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*
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* If it's an IRIX or UNICOS/mp DLT_NULL header, the upper 4 hex
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* digits would be zero and the next 2 hex digits would not be zero.
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* Furthermore, the third hex digit from the bottom would be <
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*/
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if (!BYTES_ARE_IN_FRAME(0, len, 2)) {
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ld->other++;
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return;
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}
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if (pd[0] == 0xFF && pd[1] == 0x03) {
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/*
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* Hand it to PPP.
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*/
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capture_ppp_hdlc(pd, 0, len, ld);
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} else {
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/*
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* Treat it as a normal DLT_NULL header.
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*/
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if (!BYTES_ARE_IN_FRAME(0, len, (int)sizeof(null_header))) {
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ld->other++;
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return;
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}
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memcpy((char *)&null_header, (const char *)&pd[0], sizeof(null_header));
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if ((null_header & 0xFFFF0000) != 0) {
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/*
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* It is possible that the AF_ type was only a 16 bit value.
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* IRIX and UNICOS/mp loopback snoop use a 4 byte header with
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* AF_ type in the first 2 bytes!
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* BSD AF_ types will always have the upper 8 bits as 0.
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*/
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if ((null_header & 0xFF000000) == 0 &&
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(null_header & 0x00FF0000) < 0x00060000) {
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/*
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* Looks like a IRIX or UNICOS/mp loopback header, in the
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* correct byte order. Set the null header value to the
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* AF_ type, which is in the upper 16 bits of "null_header".
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*/
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null_header >>= 16;
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} else {
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/* Byte-swap it. */
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null_header = GUINT32_SWAP_LE_BE(null_header);
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}
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} else {
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/*
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* Check for an IRIX or UNICOS/mp snoop header.
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*/
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if ((null_header & 0x000000FF) == 0 &&
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(null_header & 0x0000FF00) < 0x00000600) {
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/*
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* Looks like a IRIX or UNICOS/mp loopback header, in the
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* wrong byte order. Set the null header value to the AF_
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* type; that's in the lower 16 bits of "null_header", but
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* is byte-swapped.
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*/
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null_header = GUINT16_SWAP_LE_BE(null_header & 0xFFFF);
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}
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}
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/*
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* The null header value must be greater than the IEEE 802.3 maximum
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* frame length to be a valid Ethernet type; if it is, hand it
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* to "capture_ethertype()", otherwise treat it as a BSD AF_type (we
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* wire in the values of the BSD AF_ types, because the values
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* in the file will be BSD values, and the OS on which
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* we're building this might not have the same values or
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* might not have them defined at all; XXX - what if different
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* BSD derivatives have different values?).
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*/
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if (null_header > IEEE_802_3_MAX_LEN)
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capture_ethertype((guint16) null_header, pd, 4, len, ld);
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else {
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switch (null_header) {
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case BSD_AF_INET:
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capture_ip(pd, 4, len, ld);
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break;
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case BSD_AF_INET6_BSD:
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case BSD_AF_INET6_FREEBSD:
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case BSD_AF_INET6_DARWIN:
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capture_ipv6(pd, 4, len, ld);
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break;
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default:
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ld->other++;
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break;
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}
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}
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}
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}
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static void
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dissect_null(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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guint32 null_header;
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proto_tree *fh_tree;
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proto_item *ti;
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tvbuff_t *next_tvb;
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/*
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* See comment in "capture_null()" for an explanation of what we're
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* doing.
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*/
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if (tvb_get_ntohs(tvb, 0) == 0xFF03) {
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/*
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* Hand it to PPP.
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*/
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call_dissector(ppp_hdlc_handle, tvb, pinfo, tree);
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} else {
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/* load the top pane info. This should be overwritten by
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the next protocol in the stack */
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col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "N/A");
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col_set_str(pinfo->cinfo, COL_RES_DL_DST, "N/A");
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "N/A");
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col_set_str(pinfo->cinfo, COL_INFO, "Null/Loopback");
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/*
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* Treat it as a normal DLT_NULL header.
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*/
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tvb_memcpy(tvb, (guint8 *)&null_header, 0, sizeof(null_header));
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if ((null_header & 0xFFFF0000) != 0) {
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/*
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* It is possible that the AF_ type was only a 16 bit value.
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* IRIX and UNICOS/mp loopback snoop use a 4 byte header with
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* AF_ type in the first 2 bytes!
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* BSD AF_ types will always have the upper 8 bits as 0.
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*/
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if ((null_header & 0xFF000000) == 0 &&
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(null_header & 0x00FF0000) < 0x00060000) {
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/*
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* Looks like a IRIX or UNICOS/mp loopback header, in the
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* correct byte order. Set the null header value to the
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* AF_ type, which is in the upper 16 bits of "null_header".
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*/
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null_header >>= 16;
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} else {
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/* Byte-swap it. */
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null_header = GUINT32_SWAP_LE_BE(null_header);
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}
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} else {
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/*
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* Check for an IRIX or UNICOS/mp snoop header.
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*/
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if ((null_header & 0x000000FF) == 0 &&
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(null_header & 0x0000FF00) < 0x00000600) {
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/*
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* Looks like a IRIX or UNICOS/mp loopback header, in the
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* wrong byte order. Set the null header value to the AF_
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* type; that's in the lower 16 bits of "null_header", but
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* is byte-swapped.
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*/
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null_header = GUINT16_SWAP_LE_BE(null_header & 0xFFFF);
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}
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}
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/*
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* The null header value must be greater than the IEEE 802.3 maximum
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* frame length to be a valid Ethernet type; if it is, dissect it
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* as one, otherwise treat it as a BSD AF_type (we wire in the values
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* of the BSD AF_ types, because the values in the file will be BSD
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* values, and the OS on which we're building this might not have the
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* same values or might not have them defined at all; XXX - what if
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* different BSD derivatives have different values?).
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*/
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if (null_header > IEEE_802_3_MAX_LEN) {
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if (tree) {
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ti = proto_tree_add_item(tree, proto_null, tvb, 0, 4, ENC_NA);
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fh_tree = proto_item_add_subtree(ti, ett_null);
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proto_tree_add_uint(fh_tree, hf_null_etype, tvb, 0, 4,
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(guint16) null_header);
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}
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next_tvb = tvb_new_subset_remaining(tvb, 4);
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if (!dissector_try_uint(ethertype_dissector_table,
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(guint16) null_header, next_tvb, pinfo, tree))
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call_dissector(data_handle, next_tvb, pinfo, tree);
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} else {
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/* populate a tree in the second pane with the status of the link
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layer (ie none) */
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if (tree) {
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ti = proto_tree_add_item(tree, proto_null, tvb, 0, 4, ENC_NA);
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fh_tree = proto_item_add_subtree(ti, ett_null);
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proto_tree_add_uint(fh_tree, hf_null_family, tvb, 0, 4, null_header);
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}
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next_tvb = tvb_new_subset_remaining(tvb, 4);
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if (!dissector_try_uint(null_dissector_table, null_header,
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next_tvb, pinfo, tree)) {
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/* No sub-dissector found. Label rest of packet as "Data" */
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call_dissector(data_handle,next_tvb, pinfo, tree);
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}
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}
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}
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}
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void
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proto_register_null(void)
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{
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static hf_register_info hf[] = {
|
|
|
|
/* registered here but handled in ethertype.c */
|
|
{ &hf_null_etype,
|
|
{ "Type", "null.type", FT_UINT16, BASE_HEX, VALS(etype_vals), 0x0,
|
|
NULL, HFILL }},
|
|
|
|
{ &hf_null_family,
|
|
{ "Family", "null.family", FT_UINT32, BASE_DEC, VALS(family_vals), 0x0,
|
|
NULL, HFILL }}
|
|
};
|
|
static gint *ett[] = {
|
|
&ett_null,
|
|
};
|
|
|
|
proto_null = proto_register_protocol("Null/Loopback", "Null", "null");
|
|
proto_register_field_array(proto_null, hf, array_length(hf));
|
|
proto_register_subtree_array(ett, array_length(ett));
|
|
|
|
/* subdissector code */
|
|
null_dissector_table = register_dissector_table("null.type",
|
|
"Null type", FT_UINT32, BASE_DEC);
|
|
}
|
|
|
|
void
|
|
proto_reg_handoff_null(void)
|
|
{
|
|
dissector_handle_t null_handle;
|
|
|
|
/*
|
|
* Get a handle for the PPP-in-HDLC-like-framing dissector and
|
|
* the "I don't know what this is" dissector.
|
|
*/
|
|
ppp_hdlc_handle = find_dissector("ppp_hdlc");
|
|
data_handle = find_dissector("data");
|
|
|
|
ethertype_dissector_table = find_dissector_table("ethertype");
|
|
|
|
null_handle = create_dissector_handle(dissect_null, proto_null);
|
|
dissector_add_uint("wtap_encap", WTAP_ENCAP_NULL, null_handle);
|
|
}
|