+++ /dev/null
-/* packet-null.c
- * Routines for null packet disassembly
- *
- * $Id$
- *
- * Ethereal - Network traffic analyzer
- * By Gerald Combs <gerald@ethereal.com>
- *
- * This file created by Mike Hall <mlh@io.com>
- * Copyright 1998
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- */
-
-#ifdef HAVE_CONFIG_H
-# include "config.h"
-#endif
-
-#include <glib.h>
-
-#include <string.h>
-#include <epan/packet.h>
-#include "packet-null.h"
-#include <epan/atalk-utils.h>
-#include "prefs.h"
-#include "packet-ip.h"
-#include "packet-ipx.h"
-#include "packet-osi.h"
-#include "packet-ppp.h"
-#include "etypes.h"
-#include "aftypes.h"
-
-static dissector_table_t null_dissector_table;
-
-/* protocols and header fields */
-static int proto_null = -1;
-static int hf_null_etype = -1;
-static int hf_null_family = -1;
-
-static gint ett_null = -1;
-
-/* Null/loopback structs and definitions */
-
-/* Family values. */
-static const value_string family_vals[] = {
- {BSD_AF_INET, "IP" },
- {BSD_AF_ISO, "OSI" },
- {BSD_AF_APPLETALK, "Appletalk" },
- {BSD_AF_IPX, "Netware IPX/SPX"},
- {BSD_AF_INET6_BSD, "IPv6" },
- {BSD_AF_INET6_FREEBSD, "IPv6" },
- {BSD_AF_INET6_DARWIN, "IPv6" },
- {0, NULL }
-};
-
-static dissector_handle_t ppp_hdlc_handle;
-static dissector_handle_t data_handle;
-void
-capture_null( const guchar *pd, int len, packet_counts *ld )
-{
- guint32 null_header;
-
- /*
- * BSD drivers that use DLT_NULL - including the FreeBSD 3.2 ISDN-for-BSD
- * drivers, as well as the 4.4-Lite and FreeBSD loopback drivers -
- * stuff the AF_ value for the protocol, in *host* byte order, in the
- * first four bytes. (BSD drivers that use DLT_LOOP, such as recent
- * OpenBSD loopback drivers, stuff it in *network* byte order in the
- * first four bytes.)
- *
- * However, the IRIX and UNICOS/mp snoop socket mechanism supplies,
- * on loopback devices, a 4-byte header that has a 2 byte (big-endian)
- * AF_ value and 2 bytes of 0, so it's
- *
- * 0000AAAA
- *
- * when read on a little-endian machine and
- *
- * AAAA0000
- *
- * when read on a big-endian machine. The current CVS version of libpcap
- * compensates for this by converting it to standard 4-byte format before
- * processing the packet, but snoop captures from IRIX or UNICOS/mp
- * have the 2-byte+2-byte header, as might tcpdump or libpcap captures
- * with older versions of libpcap.
- *
- * AF_ values are small integers, and probably fit in 8 bits (current
- * values on the BSDs do), and have their upper 24 bits zero.
- * This means that, in practice, if you look at the header as a 32-bit
- * integer in host byte order:
- *
- * on a little-endian machine:
- *
- * a little-endian DLT_NULL header looks like
- *
- * 000000AA
- *
- * a big-endian DLT_NULL header, or a DLT_LOOP header, looks
- * like
- *
- * AA000000
- *
- * an IRIX or UNICOS/mp DLT_NULL header looks like
- *
- * 0000AA00
- *
- * on a big-endian machine:
- *
- * a big-endian DLT_NULL header, or a DLT_LOOP header, looks
- * like
- *
- * 000000AA
- *
- * a little-endian DLT_NULL header looks like
- *
- * AA000000
- *
- * an IRIX or UNICOS/mp DLT_NULL header looks like
- *
- * 00AA0000
- *
- * However, according to Gerald Combs, a FreeBSD ISDN PPP dump that
- * Andreas Klemm sent to ethereal-dev has a packet type of DLT_NULL,
- * and the family bits look like PPP's protocol field. (Was this an
- * older, or different, ISDN driver?) Looking at what appears to be
- * that capture file, it appears that it's using PPP in HDLC framing,
- * RFC 1549, wherein the first two octets of the frame are 0xFF
- * (address) and 0x03 (control), so the header bytes are, in order:
- *
- * 0xFF
- * 0x03
- * high-order byte of a PPP protocol field
- * low-order byte of a PPP protocol field
- *
- * If we treat that as a 32-bit host-byte-order value, it looks like
- *
- * PPPP03FF
- *
- * where PPPP is a byte-swapped PPP protocol type if we read it on
- * a little-endian machine and
- *
- * FF03PPPP
- *
- * where PPPP is a PPP protocol type if we read it on a big-endian
- * machine. 0x0000 does not appear to be a valid PPP protocol type
- * value, so at least one of those hex digits is guaranteed not to
- * be 0.
- *
- * Old versions of libpcap for Linux used DLT_NULL for loopback devices,
- * but not any other devices. (Current versions use DLT_EN10MB for it.)
- * The Linux loopback driver puts an *Ethernet* header at the beginning
- * of loopback packets, with fake source and destination addresses and
- * the appropriate Ethernet type value; however, those older versions of
- * libpcap for Linux compensated for this by skipping the source and
- * destination MAC addresses, replacing them with 2 bytes of 0.
- * This means that if we're reading the capture on a little-endian
- * machine, the header, treated as a 32-bit integer, looks like
- *
- * EEEE0000
- *
- * where EEEE is a byte-swapped Ethernet type, and if we're reading it
- * on a big-endian machine, it looks like
- *
- * 0000EEEE
- *
- * where EEEE is an Ethernet type.
- *
- * If the first 2 bytes of the header are FF 03:
- *
- * it can't be a big-endian BSD DLT_NULL header, or a DLT_LOOP
- * header, as AF_ values are small so the first 2 bytes of the
- * header would be 0;
- *
- * it can't be a little-endian BSD DLT_NULL header, as the
- * resulting AF_ value would be >= 0x03FF, which is too big
- * for an AF_ value;
- *
- * it can't be an IRIX or UNICOS/mp DLT_NULL header, as the
- * resulting AF_ value with be 0x03FF.
- *
- * So the first thing we do is check the first two bytes of the
- * header; if it's FF 03, we treat the packet as a PPP frame.
- *
- * Otherwise, if the upper 16 bits are non-zero, either:
- *
- * it's a BSD DLT_NULL or DLT_LOOP header whose AF_ value
- * is not in our byte order;
- *
- * it's an IRIX or UNICOS/mp DLT_NULL header being read on
- * a big-endian machine;
- *
- * it's a Linux DLT_NULL header being read on a little-endian
- * machine.
- *
- * In all those cases except for the IRIX or UNICOS/mp DLT_NULL header,
- * we should byte-swap it (if it's a Linux DLT_NULL header, that'll
- * put the Ethernet type in the right byte order). In the case
- * of the IRIX or UNICOS/mp DLT_NULL header, we should just get
- * the upper 16 bits as an AF_ value.
- *
- * If it's a BSD DLT_NULL or DLT_LOOP header whose AF_ value is not
- * in our byte order, then the upper 2 hex digits would be non-zero
- * and the next 2 hex digits down would be zero, as AF_ values fit in
- * 8 bits, and the upper 2 hex digits are the *lower* 8 bits of the value.
- *
- * If it's an IRIX or UNICOS/mp DLT_NULL header, the upper 2 hex digits
- * would be zero and the next 2 hex digits down would be non-zero, as
- * the upper 16 bits are a big-endian AF_ value. Furthermore, the
- * next 2 hex digits down are likely to be < 0x60, as 0x60 is 96,
- * and, so far, we're far from requiring AF_ values that high.
- *
- * If it's a Linux DLT_NULL header, the third hex digit from the top
- * will be >= 6, as Ethernet types are >= 1536, or 0x0600, and
- * it's byte-swapped, so the second 2 hex digits from the top are
- * >= 0x60.
- *
- * So, if the upper 16 bits are non-zero:
- *
- * if the upper 2 hex digits are 0 and the next 2 hex digits are
- * in the range 0x00-0x5F, we treat it as a big-endian IRIX or
- * UNICOS/mp DLT_NULL header;
- *
- * otherwise, we byte-swap it and do the next stage.
- *
- * If the upper 16 bits are zero, either:
- *
- * it's a BSD DLT_NULLor DLT_LOOP header whose AF_ value is in
- * our byte order;
- *
- * it's an IRIX or UNICOS/mp DLT_NULL header being read on
- * a little-endian machine;
- *
- * it's a Linux DLT_NULL header being read on a big-endian
- * machine.
- *
- * In all of those cases except for the IRIX or UNICOS/mp DLT_NULL header,
- * we should *not* byte-swap it. In the case of the IRIX or UNICOS/mp
- * DLT_NULL header, we should extract the AF_ value and byte-swap it.
- *
- * If it's a BSD DLT_NULL or DLT_LOOP header whose AF_ value is
- * in our byte order, the upper 6 hex digits would all be zero.
- *
- * If it's an IRIX or UNICOS/mp DLT_NULL header, the upper 4 hex
- * digits would be zero and the next 2 hex digits would not be zero.
- * Furthermore, the third hex digit from the bottom would be <
- */
- if (!BYTES_ARE_IN_FRAME(0, len, 2)) {
- ld->other++;
- return;
- }
- if (pd[0] == 0xFF && pd[1] == 0x03) {
- /*
- * Hand it to PPP.
- */
- capture_ppp_hdlc(pd, 0, len, ld);
- } else {
- /*
- * Treat it as a normal DLT_NULL header.
- */
- if (!BYTES_ARE_IN_FRAME(0, len, (int)sizeof(null_header))) {
- ld->other++;
- return;
- }
- memcpy((char *)&null_header, (const char *)&pd[0], sizeof(null_header));
-
- if ((null_header & 0xFFFF0000) != 0) {
- /*
- * It is possible that the AF_ type was only a 16 bit value.
- * IRIX and UNICOS/mp loopback snoop use a 4 byte header with
- * AF_ type in the first 2 bytes!
- * BSD AF_ types will always have the upper 8 bits as 0.
- */
- if ((null_header & 0xFF000000) == 0 &&
- (null_header & 0x00FF0000) < 0x00060000) {
- /*
- * Looks like a IRIX or UNICOS/mp loopback header, in the
- * correct byte order. Set the null header value to the
- * AF_ type, which is in the upper 16 bits of "null_header".
- */
- null_header >>= 16;
- } else {
- /* Byte-swap it. */
- null_header = BSWAP32(null_header);
- }
- } else {
- /*
- * Check for an IRIX or UNICOS/mp snoop header.
- */
- if ((null_header & 0x000000FF) == 0 &&
- (null_header & 0x0000FF00) < 0x00000600) {
- /*
- * Looks like a IRIX or UNICOS/mp loopback header, in the
- * wrong byte order. Set the null header value to the AF_
- * type; that's in the lower 16 bits of "null_header", but
- * is byte-swapped.
- */
- null_header = BSWAP16(null_header & 0xFFFF);
- }
- }
-
- /*
- * The null header value must be greater than the IEEE 802.3 maximum
- * frame length to be a valid Ethernet type; if it is, hand it
- * to "ethertype()", otherwise treat it as a BSD AF_type (we wire
- * in the values of the BSD AF_ types, because the values
- * in the file will be BSD values, and the OS on which
- * we're building this might not have the same values or
- * might not have them defined at all; XXX - what if different
- * BSD derivatives have different values?).
- */
- if (null_header > IEEE_802_3_MAX_LEN)
- capture_ethertype((guint16) null_header, pd, 4, len, ld);
- else {
-
- switch (null_header) {
-
- case BSD_AF_INET:
- capture_ip(pd, 4, len, ld);
- break;
-
- default:
- ld->other++;
- break;
- }
- }
- }
-}
-
-static void
-dissect_null(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
-{
- guint32 null_header;
- proto_tree *fh_tree;
- proto_item *ti;
- tvbuff_t *next_tvb;
-
- /*
- * See comment in "capture_null()" for an explanation of what we're
- * doing.
- */
- if (tvb_get_ntohs(tvb, 0) == 0xFF03) {
- /*
- * Hand it to PPP.
- */
- call_dissector(ppp_hdlc_handle, tvb, pinfo, tree);
- } else {
-
- /* load the top pane info. This should be overwritten by
- the next protocol in the stack */
- if(check_col(pinfo->cinfo, COL_RES_DL_SRC))
- col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "N/A" );
- if(check_col(pinfo->cinfo, COL_RES_DL_DST))
- col_set_str(pinfo->cinfo, COL_RES_DL_DST, "N/A" );
- if(check_col(pinfo->cinfo, COL_PROTOCOL))
- col_set_str(pinfo->cinfo, COL_PROTOCOL, "N/A" );
- if(check_col(pinfo->cinfo, COL_INFO))
- col_set_str(pinfo->cinfo, COL_INFO, "Null/Loopback" );
-
- /*
- * Treat it as a normal DLT_NULL header.
- */
- tvb_memcpy(tvb, (guint8 *)&null_header, 0, sizeof(null_header));
-
- if ((null_header & 0xFFFF0000) != 0) {
- /*
- * It is possible that the AF_ type was only a 16 bit value.
- * IRIX and UNICOS/mp loopback snoop use a 4 byte header with
- * AF_ type in the first 2 bytes!
- * BSD AF_ types will always have the upper 8 bits as 0.
- */
- if ((null_header & 0xFF000000) == 0 &&
- (null_header & 0x00FF0000) < 0x00060000) {
- /*
- * Looks like a IRIX or UNICOS/mp loopback header, in the
- * correct byte order. Set the null header value to the
- * AF_ type, which is in the upper 16 bits of "null_header".
- */
- null_header >>= 16;
- } else {
- /* Byte-swap it. */
- null_header = BSWAP32(null_header);
- }
- } else {
- /*
- * Check for an IRIX or UNICOS/mp snoop header.
- */
- if ((null_header & 0x000000FF) == 0 &&
- (null_header & 0x0000FF00) < 0x00000600) {
- /*
- * Looks like a IRIX or UNICOS/mp loopback header, in the
- * wrong byte order. Set the null header value to the AF_
- * type; that's in the lower 16 bits of "null_header", but
- * is byte-swapped.
- */
- null_header = BSWAP16(null_header & 0xFFFF);
- }
- }
-
- /*
- * The null header value must be greater than the IEEE 802.3 maximum
- * frame length to be a valid Ethernet type; if it is, hand it
- * to "ethertype()", otherwise treat it as a BSD AF_type (we wire
- * in the values of the BSD AF_ types, because the values
- * in the file will be BSD values, and the OS on which
- * we're building this might not have the same values or
- * might not have them defined at all; XXX - what if different
- * BSD derivatives have different values?).
- */
- if (null_header > IEEE_802_3_MAX_LEN) {
- if (tree) {
- ti = proto_tree_add_item(tree, proto_null, tvb, 0, 4, FALSE);
- fh_tree = proto_item_add_subtree(ti, ett_null);
- } else
- fh_tree = NULL;
- ethertype((guint16) null_header, tvb, 4, pinfo, tree, fh_tree, hf_null_etype, -1,
- 0);
- } else {
- /* populate a tree in the second pane with the status of the link
- layer (ie none) */
- if (tree) {
- ti = proto_tree_add_item(tree, proto_null, tvb, 0, 4, FALSE);
- fh_tree = proto_item_add_subtree(ti, ett_null);
- proto_tree_add_uint(fh_tree, hf_null_family, tvb, 0, 4, null_header);
- }
-
- next_tvb = tvb_new_subset(tvb, 4, -1, -1);
- if (!dissector_try_port(null_dissector_table, null_header,
- next_tvb, pinfo, tree)) {
- /* No sub-dissector found. Label rest of packet as "Data" */
- call_dissector(data_handle,next_tvb, pinfo, tree);
- }
- }
- }
-}
-
-void
-proto_register_null(void)
-{
- 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,
- "", HFILL }},
-
- { &hf_null_family,
- { "Family", "null.family", FT_UINT32, BASE_DEC, VALS(family_vals), 0x0,
- "", 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",
- "BSD AF_ 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.
- */
- ppp_hdlc_handle = find_dissector("ppp_hdlc");
- data_handle = find_dissector("data");
- null_handle = create_dissector_handle(dissect_null, proto_null);
- dissector_add("wtap_encap", WTAP_ENCAP_NULL, null_handle);
-}
git.samba.org / obnox / wireshark / wip.git / blobdiff