packet-llc.c

   1 /* packet-llc.c
   2  * Routines for IEEE 802.2 LLC layer
   3  * Gilbert Ramirez <gram@verdict.uthscsa.edu>
   4  *
   5  * $Id: packet-llc.c,v 1.14 1999/03/23 03:14:39 gram Exp $
   6  *
   7  * Ethereal - Network traffic analyzer
   8  * By Gerald Combs <gerald@unicom.net>
   9  * Copyright 1998 Gerald Combs
  10  *
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  25  */
  26
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #ifdef HAVE_SYS_TYPES_H
  32 # include <sys/types.h>
  33 #endif
  34
  35 #include <glib.h>
  36 #include "packet.h"
  37
  38 typedef void (capture_func_t)(const u_char *, int, guint32, packet_counts *);
  39 typedef void (dissect_func_t)(const u_char *, int, frame_data *, proto_tree *);
  40
  41 struct sap_info {
  42         guint8  sap;
  43         capture_func_t *capture_func;
  44         dissect_func_t *dissect_func;
  45         char    *text;
  46 };
  47
  48 static struct sap_info  saps[] = {
  49         { 0x00, NULL,           NULL,           "NULL LSAP" },
  50         { 0x02, NULL,           NULL,           "LLC Sub-Layer Management Individual" },
  51         { 0x03, NULL,           NULL,           "LLC Sub-Layer Management Group" },
  52         { 0x04, NULL,           NULL,           "SNA Path Control Individual" },
  53         { 0x05, NULL,           NULL,           "SNA Path Control Group" },
  54         { 0x06, capture_ip,     dissect_ip,     "TCP/IP" },
  55         { 0x08, NULL,           NULL,           "SNA" },
  56         { 0x0C, NULL,           NULL,           "SNA" },
  57         { 0x42, NULL,           NULL,           "Spanning Tree BPDU" },
  58         { 0x7F, NULL,           NULL,           "ISO 802.2" },
  59         { 0x80, NULL,           NULL,           "XNS" },
  60         { 0xAA, NULL,           NULL,           "SNAP" },
  61         /*{ 0xBA, NULL,         dissect_vines,  "Banyan Vines" },
  62         { 0xBC, NULL,           dissect_vines,  "Banyan Vines" },*/
  63         { 0xBA, NULL,           NULL,           "Banyan Vines" },
  64         { 0xBC, NULL,           NULL,           "Banyan Vines" },
  65         { 0xE0, NULL,           dissect_ipx,    "NetWare" },
  66         { 0xF0, NULL,           NULL,           "NetBIOS" },
  67         { 0xF4, NULL,           NULL,           "IBM Net Management Individual" },
  68         { 0xF5, NULL,           NULL,           "IBM Net Management Group" },
  69         { 0xF8, NULL,           NULL,           "Remote Program Load" },
  70         { 0xFC, NULL,           NULL,           "Remote Program Load" },
  71         { 0xFE, NULL,           dissect_osi,    "ISO Network Layer" },
  72         { 0xFF, NULL,           NULL,           "Global LSAP" },
  73         { 0x00, NULL,           NULL,           NULL }
  74 };
  75
  76
  77 static char*
  78 sap_text(u_char sap) {
  79         int i=0;
  80
  81         while (saps[i].text != NULL) {
  82                 if (saps[i].sap == sap) {
  83                         return saps[i].text;
  84                 }
  85                 i++;
  86         }
  87         return "Unknown";
  88 }
  89
  90 static capture_func_t *
  91 sap_capture_func(u_char sap) {
  92         int i=0;
  93
  94         while (saps[i].text != NULL) {
  95                 if (saps[i].sap == sap) {
  96                         return saps[i].capture_func;
  97                 }
  98                 i++;
  99         }
 100         return NULL;
 101 }
 102
 103 static dissect_func_t *
 104 sap_dissect_func(u_char sap) {
 105         int i=0;
 106
 107         while (saps[i].text != NULL) {
 108                 if (saps[i].sap == sap) {
 109                         return saps[i].dissect_func;
 110                 }
 111                 i++;
 112         }
 113         return dissect_data;
 114 }
 115
 116 static char*
 117 llc_org(const u_char *ptr) {
 118
 119         unsigned long org = (ptr[0] << 16) | (ptr[1] << 8) | ptr[2];
 120         char *llc_org[1] = {
 121                 "Encapsulated Ethernet"};
 122
 123         if (org > 0) {
 124                 return "Unknown";
 125         }
 126         else {
 127                 return llc_org[org];
 128         }
 129 }
 130
 131 void
 132 capture_llc(const u_char *pd, int offset, guint32 cap_len, packet_counts *ld) {
 133
 134         guint16         etype;
 135         int             is_snap;
 136         capture_func_t  *capture;
 137
 138         is_snap = (pd[offset] == 0xAA) && (pd[offset+1] == 0xAA);
 139         if (is_snap) {
 140                 etype  = (pd[offset+6] << 8) | pd[offset+7];
 141                 offset += 8;
 142                 capture_ethertype(etype, offset, pd, cap_len, ld);
 143         }
 144         else {
 145                 capture = sap_capture_func(pd[offset]);
 146
 147                 /* non-SNAP */
 148                 offset += 3;
 149
 150                 if (capture) {
 151                         capture(pd, offset, cap_len, ld);
 152                 }
 153                 else {
 154                         ld->other++;
 155                 }
 156
 157         }
 158 }
 159
 160 void
 161 dissect_llc(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
 162
 163         proto_tree      *llc_tree = NULL;
 164         proto_item      *ti;
 165         guint16         etype;
 166         int             is_snap;
 167         dissect_func_t  *dissect;
 168
 169         /* LLC Strings */
 170         char *llc_ctrl[4] = {
 171                 "Information Transfer", "Supervisory",
 172                 "", "Unnumbered Information" };
 173
 174         is_snap = (pd[offset] == 0xAA) && (pd[offset+1] == 0xAA);
 175
 176         if (check_col(fd, COL_PROTOCOL)) {
 177                 col_add_str(fd, COL_PROTOCOL, "LLC");
 178         }
 179
 180         if (tree) {
 181                 ti = proto_tree_add_item(tree, offset, (is_snap ? 8 : 3),
 182                         "Logical-Link Control");
 183                 llc_tree = proto_tree_new();
 184                 proto_item_add_subtree(ti, llc_tree, ETT_LLC);
 185                 proto_tree_add_item(llc_tree, offset,      1, "DSAP: %s (0x%02X)",
 186                         sap_text(pd[offset]), pd[offset]);
 187                 proto_tree_add_item(llc_tree, offset+1,    1, "SSAP: %s (0x%02X)",
 188                         sap_text(pd[offset+1]), pd[offset+1]);
 189                 proto_tree_add_item(llc_tree, offset+2,    1, "Control: %s",
 190                         llc_ctrl[pd[offset+2] & 3]);
 191         }
 192
 193         if (is_snap) {
 194                 if (check_col(fd, COL_INFO)) {
 195                         col_add_str(fd, COL_INFO, "802.2 LLC (SNAP)");
 196                 }
 197                 if (tree) {
 198                         proto_tree_add_item(llc_tree, offset+3,    3,
 199                                 "Organization Code: %s (%02X-%02X-%02X)",
 200                                 llc_org(&pd[offset+3]),
 201                                 pd[offset+3], pd[offset+4], pd[offset+5]);
 202                 }
 203                 etype  = (pd[offset+6] << 8) | pd[offset+7];
 204                 offset += 8;
 205                 ethertype(etype, offset, pd, fd, tree, llc_tree);
 206         }
 207         else {
 208                 if (check_col(fd, COL_INFO)) {
 209                         col_add_fstr(fd, COL_INFO, "802.2 LLC (%s)", sap_text(pd[offset]));
 210                 }
 211
 212                 dissect = sap_dissect_func(pd[offset]);
 213
 214                 /* non-SNAP */
 215                 offset += 3;
 216
 217                 if (dissect) {
 218                         dissect(pd, offset, fd, tree);
 219                 }
 220                 else {
 221                         dissect_data(pd, offset, fd, tree);
 222                 }
 223
 224         }
 225 }