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

   1 /*
   2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  */
  21 #ifndef lint
  22 static const char rcsid[] =
  23     "@(#) $Header: /tcpdump/master/tcpdump/print-sll.c,v 1.8 2002-08-01 08:53:28 risso Exp $ (LBL)";
  24 #endif
  25
  26 #ifdef HAVE_CONFIG_H
  27 #include "config.h"
  28 #endif
  29
  30 #include <tcpdump-stdinc.h>
  31
  32 #include <stdio.h>
  33 #include <string.h>
  34 #include <pcap.h>
  35
  36 #include "interface.h"
  37 #include "addrtoname.h"
  38 #include "ethertype.h"
  39
  40 #include "ether.h"
  41 #include "sll.h"
  42
  43 static inline void
  44 sll_print(register const struct sll_header *sllp, u_int length)
  45 {
  46         u_short halen;
  47
  48         switch (ntohs(sllp->sll_pkttype)) {
  49
  50         case LINUX_SLL_HOST:
  51                 (void)printf("< ");
  52                 break;
  53
  54         case LINUX_SLL_BROADCAST:
  55                 (void)printf("B ");
  56                 break;
  57
  58         case LINUX_SLL_MULTICAST:
  59                 (void)printf("M ");
  60                 break;
  61
  62         case LINUX_SLL_OTHERHOST:
  63                 (void)printf("P ");
  64                 break;
  65
  66         case LINUX_SLL_OUTGOING:
  67                 (void)printf("> ");
  68                 break;
  69
  70         default:
  71                 (void)printf("? ");
  72                 break;
  73         }
  74
  75         /*
  76          * XXX - check the link-layer address type value?
  77          * For now, we just assume 6 means Ethernet.
  78          * XXX - print others as strings of hex?
  79          */
  80         halen = ntohs(sllp->sll_halen);
  81         if (halen == 6)
  82                 (void)printf("%s ", etheraddr_string(sllp->sll_addr));
  83
  84         if (!qflag)
  85                 (void)printf("%s ", etherproto_string(sllp->sll_protocol));
  86         (void)printf("%d: ", length);
  87 }
  88
  89 /*
  90  * This is the top level routine of the printer.  'p' is the points
  91  * to the ether header of the packet, 'h->tv' is the timestamp,
  92  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
  93  * is the number of bytes actually captured.
  94  */
  95 void
  96 sll_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
  97 {
  98         u_int caplen = h->caplen;
  99         u_int length = h->len;
 100         register const struct sll_header *sllp;
 101         u_short pkttype;
 102         struct ether_header ehdr;
 103         u_short ether_type;
 104         u_short extracted_ethertype;
 105
 106         ++infodelay;
 107         ts_print(&h->ts);
 108
 109         if (caplen < SLL_HDR_LEN) {
 110                 /*
 111                  * XXX - this "can't happen" because "pcap-linux.c" always
 112                  * adds this many bytes of header to every packet in a
 113                  * cooked socket capture.
 114                  */
 115                 printf("[|sll]");
 116                 goto out;
 117         }
 118
 119         sllp = (const struct sll_header *)p;
 120
 121         /*
 122          * Fake up an Ethernet header for the benefit of printers that
 123          * insist on "packetp" pointing to an Ethernet header.
 124          */
 125         pkttype = ntohs(sllp->sll_pkttype);
 126
 127         /* The source address is in the packet header */
 128         memcpy(ehdr.ether_shost, sllp->sll_addr, ETHER_ADDR_LEN);
 129
 130         if (pkttype != LINUX_SLL_OUTGOING) {
 131                 /*
 132                  * We received this packet.
 133                  *
 134                  * We don't know the destination address, so
 135                  * we fake it - all 0's except that the
 136                  * bottommost bit of the bottommost octet
 137                  * is set for a unicast packet, all 0's except
 138                  * that the bottommost bit of the uppermost
 139                  * octet is set for a multicast packet, all
 140                  * 1's for a broadcast packet.
 141                  */
 142                 if (pkttype == LINUX_SLL_BROADCAST)
 143                         memset(ehdr.ether_dhost, 0xFF, ETHER_ADDR_LEN);
 144                 else {
 145                         memset(ehdr.ether_dhost, 0, ETHER_ADDR_LEN);
 146                         if (pkttype == LINUX_SLL_MULTICAST)
 147                                 ehdr.ether_dhost[0] = 1;
 148                         else
 149                                 ehdr.ether_dhost[ETHER_ADDR_LEN-1] = 1;
 150                 }
 151         } else {
 152                 /*
 153                  * We sent this packet; we don't know whether it's
 154                  * broadcast, multicast, or unicast, so just make
 155                  * the destination address all 0's.
 156                  */
 157                 memset(ehdr.ether_dhost, 0, ETHER_ADDR_LEN);
 158         }
 159
 160         if (eflag)
 161                 sll_print(sllp, length);
 162
 163         /*
 164          * Some printers want to get back at the ethernet addresses,
 165          * and/or check that they're not walking off the end of the packet.
 166          * Rather than pass them all the way down, we set these globals.
 167          */
 168         snapend = p + caplen;
 169         /*
 170          * Actually, the only printers that use packetp are print-arp.c
 171          * and print-bootp.c, and they assume that packetp points to an
 172          * Ethernet header.  The right thing to do is to fix them to know
 173          * which link type is in use when they excavate. XXX
 174          */
 175         packetp = (u_char *)&ehdr;
 176
 177         length -= SLL_HDR_LEN;
 178         caplen -= SLL_HDR_LEN;
 179         p += SLL_HDR_LEN;
 180
 181         ether_type = ntohs(sllp->sll_protocol);
 182
 183         /*
 184          * Is it (gag) an 802.3 encapsulation, or some non-Ethernet
 185          * packet type?
 186          */
 187         extracted_ethertype = 0;
 188         if (ether_type <= ETHERMTU) {
 189                 /*
 190                  * Yes - what type is it?
 191                  */
 192                 switch (ether_type) {
 193
 194                 case LINUX_SLL_P_802_3:
 195                         /*
 196                          * Ethernet_802.3 IPX frame.
 197                          */
 198                         ipx_print(p, length);
 199                         break;
 200
 201                 case LINUX_SLL_P_802_2:
 202                         /*
 203                          * 802.2.
 204                          * Try to print the LLC-layer header & higher layers.
 205                          */
 206                         if (llc_print(p, length, caplen, ESRC(&ehdr),
 207                             EDST(&ehdr), &extracted_ethertype) == 0)
 208                                 goto unknown;   /* unknown LLC type */
 209                         break;
 210
 211                 default:
 212                 unknown:
 213                         /* ether_type not known, print raw packet */
 214                         if (!eflag)
 215                                 sll_print(sllp, length + SLL_HDR_LEN);
 216                         if (extracted_ethertype) {
 217                                 printf("(LLC %s) ",
 218                                etherproto_string(htons(extracted_ethertype)));
 219                         }
 220                         if (!xflag && !qflag)
 221                                 default_print(p, caplen);
 222                         break;
 223                 }
 224         } else if (ether_encap_print(ether_type, p, length, caplen,
 225             &extracted_ethertype) == 0) {
 226                 /* ether_type not known, print raw packet */
 227                 if (!eflag)
 228                         sll_print(sllp, length + SLL_HDR_LEN);
 229                 if (!xflag && !qflag)
 230                         default_print(p, caplen);
 231         }
 232         if (xflag)
 233                 default_print(p, caplen);
 234  out:
 235         putchar('\n');
 236         --infodelay;
 237         if (infoprint)
 238                 info(0);
 239 }