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 1.8 2000-09-28 06:42:57 guy Exp $ (LBL)";
  26 #endif
  27
  28 #ifdef HAVE_CONFIG_H
  29 #include "config.h"
  30 #endif
  31
  32 #include <sys/param.h>
  33 #include <sys/time.h>
  34 #include <sys/types.h>
  35 #include <sys/socket.h>
  36
  37
  38 #include <netinet/in.h>
  39 #include <netinet/in_systm.h>
  40
  41 #include <stdio.h>
  42 #include <pcap.h>
  43
  44 #include "interface.h"
  45 #include "addrtoname.h"
  46 #include "ethertype.h"
  47 #include "ether.h"
  48
  49 const u_char *packetp;
  50 const u_char *snapend;
  51
  52 #define RFC1483LLC_LEN  8
  53
  54 static unsigned char rfcllc[] = {
  55         0xaa,   /* DSAP: non-ISO */
  56         0xaa,   /* SSAP: non-ISO */
  57         0x03,   /* Ctrl: Unnumbered Information Command PDU */
  58         0x00,   /* OUI: EtherType */
  59         0x00,
  60         0x00 };
  61
  62 static inline void
  63 cip_print(register const u_char *bp, int length)
  64 {
  65         int i;
  66
  67         if (memcmp(rfcllc, bp, sizeof(rfcllc))) {
  68                 if (qflag) {
  69                         for (i = 0;i < RFC1483LLC_LEN; i++)
  70                         (void)printf("%2.2x ",bp[i]);
  71                 } else {
  72                         for (i = 0;i < RFC1483LLC_LEN - 2; i++)
  73                                 (void)printf("%2.2x ",bp[i]);
  74                         etherproto_string(((u_short*)bp)[3]);
  75                 }
  76         } else {
  77                 if (qflag)
  78                         (void)printf("(null encapsulation)");
  79                 else {
  80                         (void)printf("(null encap)");
  81                         etherproto_string(ETHERTYPE_IP);
  82                 }
  83         }
  84 }
  85
  86 /*
  87  * This is the top level routine of the printer.  'p' is the points
  88  * to the raw header of the packet, 'tvp' is the timestamp,
  89  * 'length' is the length of the packet off the wire, and 'caplen'
  90  * is the number of bytes actually captured.
  91  */
  92 void
  93 cip_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
  94 {
  95         int caplen = h->caplen;
  96         int length = h->len;
  97         u_short ether_type;
  98         u_short extracted_ethertype;
  99         u_short *bp;
 100
 101         ts_print(&h->ts);
 102
 103         if (memcmp(rfcllc, p, sizeof(rfcllc))==0 && caplen < RFC1483LLC_LEN) {
 104                 printf("[|cip]");
 105                 goto out;
 106         }
 107
 108         if (eflag)
 109                 cip_print(p, length);
 110
 111         /*
 112          * Some printers want to get back at the ethernet addresses,
 113          * and/or check that they're not walking off the end of the packet.
 114          * Rather than pass them all the way down, we set these globals.
 115          */
 116         packetp = p;
 117         snapend = p + caplen;
 118
 119         if (memcmp(rfcllc, p, sizeof(rfcllc))==0) {
 120                 length -= RFC1483LLC_LEN;
 121                 caplen -= RFC1483LLC_LEN;
 122                 bp = (u_short *)p;
 123                 p += RFC1483LLC_LEN;
 124                 ether_type = ntohs(bp[3]);
 125         } else {
 126                 ether_type = ETHERTYPE_IP;
 127                 bp = (u_short *)p;
 128         }
 129
 130         /*
 131          * Is it (gag) an 802.3 encapsulation?
 132          */
 133         extracted_ethertype = 0;
 134         if (ether_type < ETHERMTU) {
 135                 /* Try to print the LLC-layer header & higher layers */
 136                 if (llc_print(p, length, caplen, NULL, NULL)==0) {
 137                         /* ether_type not known, print raw packet */
 138                         if (!eflag)
 139                                 cip_print((u_char *)bp, length);
 140                         if (extracted_ethertype) {
 141                                 printf("(LLC %s) ",
 142                                etherproto_string(htons(extracted_ethertype)));
 143                         }
 144                         if (!xflag && !qflag)
 145                                 default_print(p, caplen);
 146                 }
 147         } else if (ether_encap_print(ether_type, p, length, caplen) == 0) {
 148                 /* ether_type not known, print raw packet */
 149                 if (!eflag)
 150                         cip_print((u_char *)bp, length + RFC1483LLC_LEN);
 151                 if (!xflag && !qflag)
 152                         default_print(p, caplen);
 153         }
 154         if (xflag)
 155                 default_print(p, caplen);
 156  out:
 157         putchar('\n');
 158 }