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 1.1 2000-12-21 10:43:22 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 const u_char *packetp;
  51 const u_char *snapend;
  52
  53 static inline void
  54 sll_print(register const u_char *bp, u_int length)
  55 {
  56         register const struct sll_header *sllp;
  57         u_short halen;
  58
  59         sllp = (const struct sll_header *)bp;
  60
  61         switch (ntohs(sllp->sll_pkttype)) {
  62
  63         case LINUX_SLL_HOST:
  64                 (void)printf("< ");
  65                 break;
  66
  67         case LINUX_SLL_BROADCAST:
  68                 (void)printf("B ");
  69                 break;
  70
  71         case LINUX_SLL_MULTICAST:
  72                 (void)printf("M ");
  73                 break;
  74
  75         case LINUX_SLL_OTHERHOST:
  76                 (void)printf("P ");
  77                 break;
  78
  79         case LINUX_SLL_OUTGOING:
  80                 (void)printf("> ");
  81                 break;
  82
  83         default:
  84                 (void)printf("? ");
  85                 break;
  86         }
  87
  88         /*
  89          * XXX - check the link-layer address type value?
  90          * For now, we just assume 6 means Ethernet.
  91          * XXX - print others as strings of hex?
  92          */
  93         halen = ntohs(sllp->sll_halen);
  94         if (halen == 6)
  95                 (void)printf("%s ", etheraddr_string(sllp->sll_addr));
  96
  97         if (!qflag)
  98                 (void)printf("%s ", etherproto_string(sllp->sll_protocol));
  99         (void)printf("%d: ", length);
 100 }
 101
 102 /*
 103  * This is the top level routine of the printer.  'p' is the points
 104  * to the ether header of the packet, 'h->tv' is the timestamp,
 105  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
 106  * is the number of bytes actually captured.
 107  */
 108 void
 109 sll_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
 110 {
 111         u_int caplen = h->caplen;
 112         u_int length = h->len;
 113         register const struct sll_header *sllp;
 114         u_short pkttype;
 115         struct ether_header ehdr;
 116         u_short ether_type;
 117         u_short extracted_ethertype;
 118
 119         ts_print(&h->ts);
 120
 121         if (caplen < SLL_HDR_LEN) {
 122                 /*
 123                  * XXX - this "can't happen" because "pcap-linux.c" always
 124                  * adds this many bytes of header to every packet in a
 125                  * cooked socket capture.
 126                  */
 127                 printf("[|sll]");
 128                 goto out;
 129         }
 130
 131         sllp = (const struct sll_header *)p;
 132
 133         /*
 134          * Fake up an Ethernet header for the benefit of printers that
 135          * insist on "packetp" pointing to an Ethernet header.
 136          */
 137         pkttype = ntohs(sllp->sll_pkttype);
 138
 139         /* The source address is in the packet header */
 140         memcpy(ehdr.ether_shost, sllp->sll_addr, ETHER_ADDR_LEN);
 141
 142         if (pkttype != LINUX_SLL_OUTGOING) {
 143                 /*
 144                  * We received this packet.
 145                  *
 146                  * We don't know the destination address, so
 147                  * we fake it - all 0's except that the
 148                  * bottommost bit of the bottommost octet
 149                  * is set for a unicast packet, all 0's except
 150                  * that the bottommost bit of the uppermost
 151                  * octet is set for a multicast packet, all
 152                  * 1's for a broadcast packet.
 153                  */
 154                 if (pkttype == LINUX_SLL_BROADCAST)
 155                         memset(ehdr.ether_dhost, 0xFF, ETHER_ADDR_LEN);
 156                 else {
 157                         memset(ehdr.ether_dhost, 0, ETHER_ADDR_LEN);
 158                         if (pkttype == LINUX_SLL_MULTICAST)
 159                                 ehdr.ether_dhost[0] = 1;
 160                         else
 161                                 ehdr.ether_dhost[ETHER_ADDR_LEN-1] = 1;
 162                 }
 163         } else {
 164                 /*
 165                  * We sent this packet; we don't know whether it's
 166                  * broadcast, multicast, or unicast, so just make
 167                  * the destination address all 0's.
 168                  */
 169                 memset(ehdr.ether_dhost, 0, ETHER_ADDR_LEN);
 170         }
 171
 172         if (eflag)
 173                 sll_print(p, length);
 174
 175         /*
 176          * Some printers want to get back at the ethernet addresses,
 177          * and/or check that they're not walking off the end of the packet.
 178          * Rather than pass them all the way down, we set these globals.
 179          */
 180         packetp = p;
 181         snapend = p + caplen;
 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?
 191          */
 192         extracted_ethertype = 0;
 193         if (ether_type <= ETHERMTU) {
 194                 /* Try to print the LLC-layer header & higher layers */
 195                 if (llc_print(p, length, caplen, ESRC(&ehdr), EDST(&ehdr),
 196                     &extracted_ethertype) == 0) {
 197                         /* ether_type not known, print raw packet */
 198                         if (!eflag)
 199                                 sll_print(packetp, length);
 200                         if (extracted_ethertype) {
 201                                 printf("(LLC %s) ",
 202                                etherproto_string(htons(extracted_ethertype)));
 203                         }
 204                         if (!xflag && !qflag)
 205                                 default_print(p, caplen);
 206                 }
 207         } else if (ether_encap_print(ether_type, p, length, caplen,
 208             &extracted_ethertype) == 0) {
 209                 /* ether_type not known, print raw packet */
 210                 if (!eflag)
 211                         sll_print(p - SLL_HDR_LEN, length + SLL_HDR_LEN);
 212                 if (!xflag && !qflag)
 213                         default_print(p, caplen);
 214         }
 215         if (xflag)
 216                 default_print(p, caplen);
 217  out:
 218         putchar('\n');
 219 }