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 #ifdef HAVE_CONFIG_H
  24 #include "config.h"
  25 #endif
  26
  27 #include <string.h>
  28
  29 #include <tcpdump-stdinc.h>
  30
  31 #include "interface.h"
  32 #include "addrtoname.h"
  33
  34 #define RFC1483LLC_LEN  8
  35
  36 static const unsigned char rfcllc[] = {
  37         0xaa,   /* DSAP: non-ISO */
  38         0xaa,   /* SSAP: non-ISO */
  39         0x03,   /* Ctrl: Unnumbered Information Command PDU */
  40         0x00,   /* OUI: EtherType */
  41         0x00,
  42         0x00 };
  43
  44 static inline void
  45 cip_print(netdissect_options *ndo, int length)
  46 {
  47         /*
  48          * There is no MAC-layer header, so just print the length.
  49          */
  50         ND_PRINT((ndo, "%d: ", length));
  51 }
  52
  53 /*
  54  * This is the top level routine of the printer.  'p' points
  55  * to the LLC/SNAP or raw header of the packet, 'h->ts' is the timestamp,
  56  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
  57  * is the number of bytes actually captured.
  58  */
  59 u_int
  60 cip_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
  61 {
  62         u_int caplen = h->caplen;
  63         u_int length = h->len;
  64         u_short extracted_ethertype;
  65
  66         if (memcmp(rfcllc, p, sizeof(rfcllc))==0 && caplen < RFC1483LLC_LEN) {
  67                 ND_PRINT((ndo, "[|cip]"));
  68                 return (0);
  69         }
  70
  71         if (ndo->ndo_eflag)
  72                 cip_print(ndo, length);
  73
  74         if (memcmp(rfcllc, p, sizeof(rfcllc)) == 0) {
  75                 /*
  76                  * LLC header is present.  Try to print it & higher layers.
  77                  */
  78                 if (llc_print(ndo, p, length, caplen, NULL, NULL,
  79                     &extracted_ethertype) == 0) {
  80                         /* ether_type not known, print raw packet */
  81                         if (!ndo->ndo_eflag)
  82                                 cip_print(ndo, length);
  83                         if (extracted_ethertype) {
  84                                 ND_PRINT((ndo, "(LLC %s) ",
  85                                etherproto_string(htons(extracted_ethertype))));
  86                         }
  87                         if (!ndo->ndo_suppress_default_print)
  88                                 ND_DEFAULTPRINT(p, caplen);
  89                 }
  90         } else {
  91                 /*
  92                  * LLC header is absent; treat it as just IP.
  93                  */
  94                 ip_print(ndo, p, length);
  95         }
  96
  97         return (0);
  98 }
  99
 100
 101 /*
 102  * Local Variables:
 103  * c-style: whitesmith
 104  * c-basic-offset: 8
 105  * End:
 106  */