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 1.5 2001-06-08 04:48:23 guy Exp $ (LBL)";
  24 #endif
  25
  26 #ifdef HAVE_CONFIG_H
  27 #include "config.h"
  28 #endif
  29
  30 #include <sys/param.h>
  31 #include <sys/time.h>
  32 #include <sys/socket.h>
  33
  34 struct mbuf;
  35 struct rtentry;
  36
  37 #include <netinet/in.h>
  38
  39 #include <stdio.h>
  40 #include <string.h>
  41 #include <pcap.h>
  42
  43 #include "interface.h"
  44 #include "addrtoname.h"
  45 #include "ethertype.h"
  46
  47 #include "ether.h"
  48 #include "sll.h"
  49
  50 static inline void
  51 sll_print(register const struct sll_header *sllp, u_int length)
  52 {
  53         u_short halen;
  54
  55         switch (ntohs(sllp->sll_pkttype)) {
  56
  57         case LINUX_SLL_HOST:
  58                 (void)printf("< ");
  59                 break;
  60
  61         case LINUX_SLL_BROADCAST:
  62                 (void)printf("B ");
  63                 break;
  64
  65         case LINUX_SLL_MULTICAST:
  66                 (void)printf("M ");
  67                 break;
  68
  69         case LINUX_SLL_OTHERHOST:
  70                 (void)printf("P ");
  71                 break;
  72
  73         case LINUX_SLL_OUTGOING:
  74                 (void)printf("> ");
  75                 break;
  76
  77         default:
  78                 (void)printf("? ");
  79                 break;
  80         }
  81
  82         /*
  83          * XXX - check the link-layer address type value?
  84          * For now, we just assume 6 means Ethernet.
  85          * XXX - print others as strings of hex?
  86          */
  87         halen = ntohs(sllp->sll_halen);
  88         if (halen == 6)
  89                 (void)printf("%s ", etheraddr_string(sllp->sll_addr));
  90
  91         if (!qflag)
  92                 (void)printf("%s ", etherproto_string(sllp->sll_protocol));
  93         (void)printf("%d: ", length);
  94 }
  95
  96 /*
  97  * This is the top level routine of the printer.  'p' is the points
  98  * to the ether header of the packet, 'h->tv' is the timestamp,
  99  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
 100  * is the number of bytes actually captured.
 101  */
 102 void
 103 sll_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
 104 {
 105         u_int caplen = h->caplen;
 106         u_int length = h->len;
 107         register const struct sll_header *sllp;
 108         u_short pkttype;
 109         struct ether_header ehdr;
 110         u_short ether_type;
 111         u_short extracted_ethertype;
 112
 113         ts_print(&h->ts);
 114
 115         if (caplen < SLL_HDR_LEN) {
 116                 /*
 117                  * XXX - this "can't happen" because "pcap-linux.c" always
 118                  * adds this many bytes of header to every packet in a
 119                  * cooked socket capture.
 120                  */
 121                 printf("[|sll]");
 122                 goto out;
 123         }
 124
 125         sllp = (const struct sll_header *)p;
 126
 127         /*
 128          * Fake up an Ethernet header for the benefit of printers that
 129          * insist on "packetp" pointing to an Ethernet header.
 130          */
 131         pkttype = ntohs(sllp->sll_pkttype);
 132
 133         /* The source address is in the packet header */
 134         memcpy(ehdr.ether_shost, sllp->sll_addr, ETHER_ADDR_LEN);
 135
 136         if (pkttype != LINUX_SLL_OUTGOING) {
 137                 /*
 138                  * We received this packet.
 139                  *
 140                  * We don't know the destination address, so
 141                  * we fake it - all 0's except that the
 142                  * bottommost bit of the bottommost octet
 143                  * is set for a unicast packet, all 0's except
 144                  * that the bottommost bit of the uppermost
 145                  * octet is set for a multicast packet, all
 146                  * 1's for a broadcast packet.
 147                  */
 148                 if (pkttype == LINUX_SLL_BROADCAST)
 149                         memset(ehdr.ether_dhost, 0xFF, ETHER_ADDR_LEN);
 150                 else {
 151                         memset(ehdr.ether_dhost, 0, ETHER_ADDR_LEN);
 152                         if (pkttype == LINUX_SLL_MULTICAST)
 153                                 ehdr.ether_dhost[0] = 1;
 154                         else
 155                                 ehdr.ether_dhost[ETHER_ADDR_LEN-1] = 1;
 156                 }
 157         } else {
 158                 /*
 159                  * We sent this packet; we don't know whether it's
 160                  * broadcast, multicast, or unicast, so just make
 161                  * the destination address all 0's.
 162                  */
 163                 memset(ehdr.ether_dhost, 0, ETHER_ADDR_LEN);
 164         }
 165
 166         if (eflag)
 167                 sll_print(sllp, length);
 168
 169         /*
 170          * Some printers want to get back at the ethernet addresses,
 171          * and/or check that they're not walking off the end of the packet.
 172          * Rather than pass them all the way down, we set these globals.
 173          */
 174         snapend = p + caplen;
 175         /*
 176          * Actually, the only printers that use packetp are print-arp.c
 177          * and print-bootp.c, and they assume that packetp points to an
 178          * Ethernet header.  The right thing to do is to fix them to know
 179          * which link type is in use when they excavate. XXX
 180          */
 181         packetp = (u_char *)&ehdr;
 182
 183         length -= SLL_HDR_LEN;
 184         caplen -= SLL_HDR_LEN;
 185         p += SLL_HDR_LEN;
 186
 187         ether_type = ntohs(sllp->sll_protocol);
 188
 189         /*
 190          * Is it (gag) an 802.3 encapsulation, or some non-Ethernet
 191          * packet type?
 192          */
 193         extracted_ethertype = 0;
 194         if (ether_type <= ETHERMTU) {
 195                 /*
 196                  * Yes - what type is it?
 197                  */
 198                 switch (ether_type) {
 199
 200                 case LINUX_SLL_P_802_3:
 201                         /*
 202                          * Ethernet_802.3 IPX frame.
 203                          */
 204                         ipx_print(p, length);
 205                         break;
 206
 207                 case LINUX_SLL_P_802_2:
 208                         /*
 209                          * 802.2.
 210                          * Try to print the LLC-layer header & higher layers.
 211                          */
 212                         if (llc_print(p, length, caplen, ESRC(&ehdr),
 213                             EDST(&ehdr), &extracted_ethertype) == 0)
 214                                 goto unknown;   /* unknown LLC type */
 215                         break;
 216
 217                 default:
 218                 unknown:
 219                         /* ether_type not known, print raw packet */
 220                         if (!eflag)
 221                                 sll_print(sllp, length + SLL_HDR_LEN);
 222                         if (extracted_ethertype) {
 223                                 printf("(LLC %s) ",
 224                                etherproto_string(htons(extracted_ethertype)));
 225                         }
 226                         if (!xflag && !qflag)
 227                                 default_print(p, caplen);
 228                         break;
 229                 }
 230         } else if (ether_encap_print(ether_type, p, length, caplen,
 231             &extracted_ethertype) == 0) {
 232                 /* ether_type not known, print raw packet */
 233                 if (!eflag)
 234                         sll_print(sllp, length + SLL_HDR_LEN);
 235                 if (!xflag && !qflag)
 236                         default_print(p, caplen);
 237         }
 238         if (xflag)
 239                 default_print(p, caplen);
 240  out:
 241         putchar('\n');
 242 }