mirror of
https://github.com/the-tcpdump-group/tcpdump.git
synced 2024-11-30 21:44:49 +08:00
bd00116d80
Have llc_print() return the length of the LLC header, plus the length of the SNAP header, if available - or, if it couldn't dissect the payload, return the *negative* of that sum. Use that return value in link-layer printers.
103 lines
2.4 KiB
C
103 lines
2.4 KiB
C
/*
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* Marko Kiiskila carnil@cs.tut.fi
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*
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* Tampere University of Technology - Telecommunications Laboratory
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*
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* Permission to use, copy, modify and distribute this
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* software and its documentation is hereby granted,
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* provided that both the copyright notice and this
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* permission notice appear in all copies of the software,
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* derivative works or modified versions, and any portions
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* thereof, that both notices appear in supporting
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* documentation, and that the use of this software is
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* acknowledged in any publications resulting from using
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* the software.
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*
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* TUT ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION AND DISCLAIMS ANY LIABILITY OF ANY KIND FOR
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* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS
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* SOFTWARE.
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*
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <string.h>
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#include <tcpdump-stdinc.h>
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#include "interface.h"
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#include "addrtoname.h"
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#define RFC1483LLC_LEN 8
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static const unsigned char rfcllc[] = {
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0xaa, /* DSAP: non-ISO */
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0xaa, /* SSAP: non-ISO */
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0x03, /* Ctrl: Unnumbered Information Command PDU */
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0x00, /* OUI: EtherType */
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0x00,
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0x00 };
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static inline void
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cip_print(netdissect_options *ndo, int length)
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{
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/*
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* There is no MAC-layer header, so just print the length.
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*/
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ND_PRINT((ndo, "%d: ", length));
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}
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/*
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* This is the top level routine of the printer. 'p' points
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* to the LLC/SNAP or raw header of the packet, 'h->ts' is the timestamp,
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* 'h->len' is the length of the packet off the wire, and 'h->caplen'
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* is the number of bytes actually captured.
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*/
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u_int
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cip_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
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{
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u_int caplen = h->caplen;
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u_int length = h->len;
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int llc_hdrlen;
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if (memcmp(rfcllc, p, sizeof(rfcllc))==0 && caplen < RFC1483LLC_LEN) {
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ND_PRINT((ndo, "[|cip]"));
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return (0);
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}
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if (ndo->ndo_eflag)
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cip_print(ndo, length);
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if (memcmp(rfcllc, p, sizeof(rfcllc)) == 0) {
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/*
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* LLC header is present. Try to print it & higher layers.
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*/
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llc_hdrlen = llc_print(ndo, p, length, caplen, NULL, NULL);
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if (llc_hdrlen < 0) {
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/* packet type not known, print raw packet */
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if (!ndo->ndo_suppress_default_print)
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ND_DEFAULTPRINT(p, caplen);
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llc_hdrlen = -llc_hdrlen;
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}
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} else {
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/*
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* LLC header is absent; treat it as just IP.
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*/
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llc_hdrlen = 0;
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ip_print(ndo, p, length);
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}
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return (llc_hdrlen);
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}
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/*
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* Local Variables:
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* c-style: whitesmith
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* c-basic-offset: 8
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* End:
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*/
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