The Tcpdump Group git mirrors - tcpdump/blob - print-cip.c

   1 /*
   2  * Marko Kiiskila carnil@cs.tut.fi
   3  *
   4  * Tampere University of Technology - Telecommunications Laboratory
   5  *
   6  * Permission to use, copy, modify and distribute this
   7  * software and its documentation is hereby granted,
   8  * provided that both the copyright notice and this
   9  * permission notice appear in all copies of the software,
  10  * derivative works or modified versions, and any portions
  11  * thereof, that both notices appear in supporting
  12  * documentation, and that the use of this software is
  13  * acknowledged in any publications resulting from using
  14  * the software.
  15  *
  16  * TUT ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  17  * CONDITION AND DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  18  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS
  19  * SOFTWARE.
  20  *
  21  */
  22
  23 /* \summary: Classical-IP over ATM printer */
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include "config.h"
  27 #endif
  28
  29 #include <string.h>
  30
  31 #include <netdissect-stdinc.h>
  32
  33 #include "netdissect.h"
  34 #include "addrtoname.h"
  35
  36 #define RFC1483LLC_LEN  8
  37
  38 static const unsigned char rfcllc[] = {
  39         0xaa,   /* DSAP: non-ISO */
  40         0xaa,   /* SSAP: non-ISO */
  41         0x03,   /* Ctrl: Unnumbered Information Command PDU */
  42         0x00,   /* OUI: EtherType */
  43         0x00,
  44         0x00 };
  45
  46 static inline void
  47 cip_print(netdissect_options *ndo, int length)
  48 {
  49         /*
  50          * There is no MAC-layer header, so just print the length.
  51          */
  52         ND_PRINT((ndo, "%d: ", length));
  53 }
  54
  55 /*
  56  * This is the top level routine of the printer.  'p' points
  57  * to the LLC/SNAP or raw header of the packet, 'h->ts' is the timestamp,
  58  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
  59  * is the number of bytes actually captured.
  60  */
  61 u_int
  62 cip_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
  63 {
  64         u_int caplen = h->caplen;
  65         u_int length = h->len;
  66         int llc_hdrlen;
  67
  68         if (memcmp(rfcllc, p, sizeof(rfcllc))==0 && caplen < RFC1483LLC_LEN) {
  69                 ND_PRINT((ndo, "[|cip]"));
  70                 return (0);
  71         }
  72
  73         if (ndo->ndo_eflag)
  74                 cip_print(ndo, length);
  75
  76         if (memcmp(rfcllc, p, sizeof(rfcllc)) == 0) {
  77                 /*
  78                  * LLC header is present.  Try to print it & higher layers.
  79                  */
  80                 llc_hdrlen = llc_print(ndo, p, length, caplen, NULL, NULL);
  81                 if (llc_hdrlen < 0) {
  82                         /* packet type not known, print raw packet */
  83                         if (!ndo->ndo_suppress_default_print)
  84                                 ND_DEFAULTPRINT(p, caplen);
  85                         llc_hdrlen = -llc_hdrlen;
  86                 }
  87         } else {
  88                 /*
  89                  * LLC header is absent; treat it as just IP.
  90                  */
  91                 llc_hdrlen = 0;
  92                 ip_print(ndo, p, length);
  93         }
  94
  95         return (llc_hdrlen);
  96 }
  97
  98
  99 /*
 100  * Local Variables:
 101  * c-style: whitesmith
 102  * c-basic-offset: 8
 103  * End:
 104  */