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 #ifndef lint
  24 static const char rcsid[] =
  25     "@(#) $Header: /tcpdump/master/tcpdump/print-cip.c,v 1.19 2002-09-05 21:25:38 guy Exp $ (LBL)";
  26 #endif
  27
  28 #ifdef HAVE_CONFIG_H
  29 #include "config.h"
  30 #endif
  31
  32 #include <string.h>
  33
  34 #include <tcpdump-stdinc.h>
  35
  36 #include <stdio.h>
  37 #include <pcap.h>
  38
  39 #include "interface.h"
  40 #include "addrtoname.h"
  41 #include "ethertype.h"
  42 #include "ether.h"
  43
  44 #define RFC1483LLC_LEN  8
  45
  46 static unsigned char rfcllc[] = {
  47         0xaa,   /* DSAP: non-ISO */
  48         0xaa,   /* SSAP: non-ISO */
  49         0x03,   /* Ctrl: Unnumbered Information Command PDU */
  50         0x00,   /* OUI: EtherType */
  51         0x00,
  52         0x00 };
  53
  54 static inline void
  55 cip_print(int length)
  56 {
  57         /*
  58          * There is no MAC-layer header, so just print the length.
  59          */
  60         printf("%d: ", length);
  61 }
  62
  63 /*
  64  * This is the top level routine of the printer.  'p' points
  65  * to the LLC/SNAP or raw header of the packet, 'h->ts' is the timestamp,
  66  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
  67  * is the number of bytes actually captured.
  68  */
  69 void
  70 cip_if_print(u_char *user _U_, const struct pcap_pkthdr *h, const u_char *p)
  71 {
  72         u_int caplen = h->caplen;
  73         u_int length = h->len;
  74         u_short extracted_ethertype;
  75
  76         ++infodelay;
  77         ts_print(&h->ts);
  78
  79         if (memcmp(rfcllc, p, sizeof(rfcllc))==0 && caplen < RFC1483LLC_LEN) {
  80                 printf("[|cip]");
  81                 goto out;
  82         }
  83
  84         if (eflag)
  85                 cip_print(length);
  86
  87         /*
  88          * Some printers want to get back at the ethernet addresses,
  89          * and/or check that they're not walking off the end of the packet.
  90          * Rather than pass them all the way down, we set these globals.
  91          */
  92         packetp = p;
  93         snapend = p + caplen;
  94
  95         if (memcmp(rfcllc, p, sizeof(rfcllc)) == 0) {
  96                 /*
  97                  * LLC header is present.  Try to print it & higher layers.
  98                  */
  99                 if (llc_print(p, length, caplen, NULL, NULL,
 100                     &extracted_ethertype) == 0) {
 101                         /* ether_type not known, print raw packet */
 102                         if (!eflag)
 103                                 cip_print(length);
 104                         if (extracted_ethertype) {
 105                                 printf("(LLC %s) ",
 106                                etherproto_string(htons(extracted_ethertype)));
 107                         }
 108                         if (!xflag && !qflag)
 109                                 default_print(p, caplen);
 110                 }
 111         } else {
 112                 /*
 113                  * LLC header is absent; treat it as just IP.
 114                  */
 115                 ip_print(p, length);
 116         }
 117
 118         if (xflag)
 119                 default_print(p, caplen);
 120  out:
 121         putchar('\n');
 122         --infodelay;
 123         if (infoprint)
 124                 info(0);
 125 }