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 <stdio.h>
  32 #include <pcap.h>
  33
  34 #include "interface.h"
  35 #include "addrtoname.h"
  36 #include "ethertype.h"
  37 #include "ether.h"
  38
  39 #define RFC1483LLC_LEN  8
  40
  41 static const unsigned char rfcllc[] = {
  42         0xaa,   /* DSAP: non-ISO */
  43         0xaa,   /* SSAP: non-ISO */
  44         0x03,   /* Ctrl: Unnumbered Information Command PDU */
  45         0x00,   /* OUI: EtherType */
  46         0x00,
  47         0x00 };
  48
  49 static inline void
  50 cip_print(int length)
  51 {
  52         /*
  53          * There is no MAC-layer header, so just print the length.
  54          */
  55         printf("%d: ", length);
  56 }
  57
  58 /*
  59  * This is the top level routine of the printer.  'p' points
  60  * to the LLC/SNAP or raw header of the packet, 'h->ts' is the timestamp,
  61  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
  62  * is the number of bytes actually captured.
  63  */
  64 u_int
  65 cip_if_print(const struct pcap_pkthdr *h, const u_char *p)
  66 {
  67         u_int caplen = h->caplen;
  68         u_int length = h->len;
  69         u_short extracted_ethertype;
  70
  71         if (memcmp(rfcllc, p, sizeof(rfcllc))==0 && caplen < RFC1483LLC_LEN) {
  72                 printf("[|cip]");
  73                 return (0);
  74         }
  75
  76         if (eflag)
  77                 cip_print(length);
  78
  79         if (memcmp(rfcllc, p, sizeof(rfcllc)) == 0) {
  80                 /*
  81                  * LLC header is present.  Try to print it & higher layers.
  82                  */
  83                 if (llc_print(p, length, caplen, NULL, NULL,
  84                     &extracted_ethertype) == 0) {
  85                         /* ether_type not known, print raw packet */
  86                         if (!eflag)
  87                                 cip_print(length);
  88                         if (extracted_ethertype) {
  89                                 printf("(LLC %s) ",
  90                                etherproto_string(htons(extracted_ethertype)));
  91                         }
  92                         if (!suppress_default_print)
  93                                 default_print(p, caplen);
  94                 }
  95         } else {
  96                 /*
  97                  * LLC header is absent; treat it as just IP.
  98                  */
  99                 ip_print(gndo, p, length);
 100         }
 101
 102         return (0);
 103 }
 104
 105
 106 /*
 107  * Local Variables:
 108  * c-style: whitesmith
 109  * c-basic-offset: 8
 110  * End:
 111  */