epan/dissectors/packet-icap.c

   1 /* packet-icap.c
   2  * Routines for ICAP packet disassembly
   3  * RFC 3507
   4  *
   5  * Srishylam Simharajan simha@netapp.com
   6  *
   7  * $Id$
   8  *
   9  * Ethereal - Network traffic analyzer
  10  * By Gerald Combs <gerald@ethereal.com>
  11  * Copyright 1998 Gerald Combs
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * as published by the Free Software Foundation; either version 2
  16  * of the License, or (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  26  */
  27
  28 #ifdef HAVE_CONFIG_H
  29 #include "config.h"
  30 #endif
  31
  32 #include <string.h>
  33 #include <ctype.h>
  34
  35 #include <glib.h>
  36 #include <epan/packet.h>
  37 #include <epan/strutil.h>
  38
  39 typedef enum _icap_type {
  40         ICAP_OPTIONS,
  41         ICAP_REQMOD,
  42         ICAP_RESPMOD,
  43         ICAP_RESPONSE,
  44         ICAP_OTHER
  45 } icap_type_t;
  46
  47 static int proto_icap = -1;
  48 static int hf_icap_response = -1;
  49 static int hf_icap_reqmod = -1;
  50 static int hf_icap_respmod = -1;
  51 static int hf_icap_options = -1;
  52 static int hf_icap_other = -1;
  53
  54 static gint ett_icap = -1;
  55
  56 static dissector_handle_t data_handle;
  57
  58 #define TCP_PORT_ICAP                   1344
  59 static int is_icap_message(const guchar *data, int linelen, icap_type_t *type);
  60 static void
  61 dissect_icap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  62 {
  63         proto_tree      *icap_tree = NULL;
  64         proto_item      *ti = NULL;
  65         gint            offset = 0;
  66         const guchar    *line;
  67         gint            next_offset;
  68         const guchar    *linep, *lineend;
  69         int             linelen;
  70         guchar          c;
  71         icap_type_t     icap_type;
  72         int             datalen;
  73
  74         if (check_col(pinfo->cinfo, COL_PROTOCOL))
  75                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "ICAP");
  76
  77         if (check_col(pinfo->cinfo, COL_INFO)) {
  78                 /*
  79                  * Put the first line from the buffer into the summary
  80                  * if it's an ICAP header (but leave out the
  81                  * line terminator).
  82                  * Otherwise, just call it a continuation.
  83                  *
  84                  * Note that "tvb_find_line_end()" will return a value that
  85                  * is not longer than what's in the buffer, so the
  86                  * "tvb_get_ptr()" call won't throw an exception.
  87                  */
  88                 linelen = tvb_find_line_end(tvb, offset, -1, &next_offset,
  89                     FALSE);
  90                 line = tvb_get_ptr(tvb, offset, linelen);
  91                 icap_type = ICAP_OTHER; /* type not known yet */
  92                 if (is_icap_message(line, linelen, &icap_type))
  93                         col_add_str(pinfo->cinfo, COL_INFO,
  94                             format_text(line, linelen));
  95                 else
  96                         col_set_str(pinfo->cinfo, COL_INFO, "Continuation");
  97         }
  98
  99         if (tree) {
 100                 ti = proto_tree_add_item(tree, proto_icap, tvb, offset, -1,
 101                     FALSE);
 102                 icap_tree = proto_item_add_subtree(ti, ett_icap);
 103         }
 104
 105         /*
 106          * Process the packet data, a line at a time.
 107          */
 108         icap_type = ICAP_OTHER; /* type not known yet */
 109         while (tvb_offset_exists(tvb, offset)) {
 110                 gboolean is_icap = FALSE;
 111                 gboolean loop_done = FALSE;
 112                 /*
 113                  * Find the end of the line.
 114                  */
 115                 linelen = tvb_find_line_end(tvb, offset, -1, &next_offset,
 116                     FALSE);
 117
 118                 /*
 119                  * Get a buffer that refers to the line.
 120                  */
 121                 line = tvb_get_ptr(tvb, offset, linelen);
 122                 lineend = line + linelen;
 123
 124                 /*
 125                  * find header format
 126                  */
 127                 if (is_icap_message(line, linelen, &icap_type)) {
 128                         is_icap = TRUE;
 129                         goto is_icap_header;
 130                 }
 131
 132                 /*
 133                  * if it looks like a blank line, end of header perhaps?
 134                  */
 135                 if (linelen == 0) {
 136                         is_icap = TRUE;
 137                         goto is_icap_header;
 138                 }
 139
 140                 /*
 141                  * No.  Does it look like a header?
 142                  */
 143                 linep = line;
 144                 loop_done = FALSE;
 145                 while (linep < lineend && (!loop_done)) {
 146                         c = *linep++;
 147
 148                         /*
 149                          * This must be a CHAR to be part of a token; that
 150                          * means it must be ASCII.
 151                          */
 152                         if (!isascii(c)) {
 153                                 is_icap = FALSE;
 154                                 break;  /* not ASCII, thus not a CHAR */
 155                         }
 156
 157                         /*
 158                          * This mustn't be a CTL to be part of a token.
 159                          *
 160                          * XXX - what about leading LWS on continuation
 161                          * lines of a header?
 162                          */
 163                         if (iscntrl(c)) {
 164                                 is_icap = FALSE;
 165                                 break;  /* CTL, not part of a header */
 166                         }
 167
 168                         switch (c) {
 169
 170                         case '(':
 171                         case ')':
 172                         case '<':
 173                         case '>':
 174                         case '@':
 175                         case ',':
 176                         case ';':
 177                         case '\\':
 178                         case '"':
 179                         case '/':
 180                         case '[':
 181                         case ']':
 182                         case '?':
 183                         case '=':
 184                         case '{':
 185                         case '}':
 186                                 /*
 187                                  * It's a separator, so it's not part of a
 188                                  * token, so it's not a field name for the
 189                                  * beginning of a header.
 190                                  *
 191                                  * (We don't have to check for HT; that's
 192                                  * already been ruled out by "iscntrl()".)
 193                                  *
 194                                  * XXX - what about ' '?  HTTP's checks
 195                                  * check for that.
 196                                  */
 197                                 is_icap = FALSE;
 198                                 loop_done = TRUE;
 199                                 break;
 200
 201                         case ':':
 202                                 /*
 203                                  * This ends the token; we consider this
 204                                  * to be a header.
 205                                  */
 206                                 is_icap = TRUE;
 207                                 goto is_icap_header;
 208                                 break;
 209                         }
 210                 }
 211
 212                 /*
 213                  * We don't consider this part of an ICAP message,
 214                  * so we don't display it.
 215                  * (Yeah, that means we don't display, say, a text/icap
 216                  * page, but you can get that from the data pane.)
 217                  */
 218                 if (!is_icap)
 219                         break;
 220 is_icap_header:
 221                 if (tree) {
 222                         proto_tree_add_text(icap_tree, tvb, offset,
 223                                 next_offset - offset, "%s",
 224                                 tvb_format_text(tvb, offset,
 225                                                 next_offset - offset)
 226                                 );
 227                 }
 228                 offset = next_offset;
 229         }
 230
 231         if (tree) {
 232                 switch (icap_type) {
 233
 234                 case ICAP_OPTIONS:
 235                         proto_tree_add_boolean_hidden(icap_tree,
 236                             hf_icap_options, tvb, 0, 0, 1);
 237                         break;
 238
 239                 case ICAP_REQMOD:
 240                         proto_tree_add_boolean_hidden(icap_tree,
 241                             hf_icap_reqmod, tvb, 0, 0, 1);
 242                         break;
 243
 244                 case ICAP_RESPMOD:
 245                         proto_tree_add_boolean_hidden(icap_tree,
 246                             hf_icap_respmod, tvb, 0, 0, 1);
 247                         break;
 248
 249                 case ICAP_RESPONSE:
 250                         proto_tree_add_boolean_hidden(icap_tree,
 251                             hf_icap_response, tvb, 0, 0, 1);
 252                         break;
 253
 254                 case ICAP_OTHER:
 255                 default:
 256                         break;
 257                 }
 258         }
 259
 260         datalen = tvb_length_remaining(tvb, offset);
 261         if (datalen > 0) {
 262                 call_dissector(data_handle,
 263                     tvb_new_subset(tvb, offset, -1, -1), pinfo, icap_tree);
 264         }
 265 }
 266
 267
 268 static int
 269 is_icap_message(const guchar *data, int linelen, icap_type_t *type)
 270 {
 271 #define ICAP_COMPARE(string, length, msgtype) {         \
 272         if (strncmp(data, string, length) == 0) {       \
 273                 if (*type == ICAP_OTHER)                \
 274                         *type = msgtype;                \
 275                 return TRUE;                            \
 276         }                                               \
 277 }
 278         /*
 279          * From draft-elson-opes-icap-01(72).txt
 280          */
 281         if (linelen >= 5) {
 282                 ICAP_COMPARE("ICAP/", 5, ICAP_RESPONSE); /* response */
 283         }
 284         if (linelen >= 7) {
 285                 ICAP_COMPARE("REQMOD ", 7, ICAP_REQMOD); /* request mod */
 286         }
 287         if (linelen >= 8) {
 288                 ICAP_COMPARE("OPTIONS ", 8, ICAP_OPTIONS); /* options */
 289                 ICAP_COMPARE("RESPMOD ", 8, ICAP_RESPMOD); /* response mod */
 290         }
 291         return FALSE;
 292 #undef ICAP_COMPARE
 293 }
 294
 295 void
 296 proto_register_icap(void)
 297 {
 298         static hf_register_info hf[] = {
 299             { &hf_icap_response,
 300               { "Response",             "icap.response",
 301                 FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 302                 "TRUE if ICAP response", HFILL }},
 303             { &hf_icap_reqmod,
 304               { "Reqmod",               "icap.reqmod",
 305                 FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 306                 "TRUE if ICAP reqmod", HFILL }},
 307             { &hf_icap_respmod,
 308               { "Respmod",              "icap.respmod",
 309                 FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 310                 "TRUE if ICAP respmod", HFILL }},
 311             { &hf_icap_options,
 312               { "Options",              "icap.options",
 313                 FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 314                 "TRUE if ICAP options", HFILL }},
 315             { &hf_icap_other,
 316               { "Other",                "icap.other",
 317                 FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 318                 "TRUE if ICAP other", HFILL }},
 319         };
 320         static gint *ett[] = {
 321                 &ett_icap,
 322         };
 323
 324         proto_icap = proto_register_protocol(
 325                         "Internet Content Adaptation Protocol",
 326                         "ICAP", "icap");
 327         proto_register_field_array(proto_icap, hf, array_length(hf));
 328         proto_register_subtree_array(ett, array_length(ett));
 329
 330 }
 331
 332 void
 333 proto_reg_handoff_icap(void)
 334 {
 335         dissector_handle_t icap_handle;
 336
 337         data_handle = find_dissector("data");
 338         icap_handle = create_dissector_handle(dissect_icap, proto_icap);
 339         dissector_add("tcp.port", TCP_PORT_ICAP, icap_handle);
 340 }