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  * Wireshark - Network traffic analyzer
  10  * By Gerald Combs <gerald@wireshark.org>
  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         proto_item      *hidden_item;
  66         gint            offset = 0;
  67         const guchar    *line;
  68         gint            next_offset;
  69         const guchar    *linep, *lineend;
  70         int             linelen;
  71         guchar          c;
  72         icap_type_t     icap_type;
  73         int             datalen;
  74
  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                         }
 209                 }
 210
 211                 /*
 212                  * We don't consider this part of an ICAP message,
 213                  * so we don't display it.
 214                  * (Yeah, that means we don't display, say, a text/icap
 215                  * page, but you can get that from the data pane.)
 216                  */
 217                 if (!is_icap)
 218                         break;
 219 is_icap_header:
 220                 if (tree) {
 221                         proto_tree_add_text(icap_tree, tvb, offset,
 222                                 next_offset - offset, "%s",
 223                                 tvb_format_text(tvb, offset,
 224                                                 next_offset - offset)
 225                                 );
 226                 }
 227                 offset = next_offset;
 228         }
 229
 230         if (tree) {
 231                 switch (icap_type) {
 232
 233                 case ICAP_OPTIONS:
 234                         hidden_item = proto_tree_add_boolean(icap_tree,
 235                                             hf_icap_options, tvb, 0, 0, 1);
 236                         PROTO_ITEM_SET_HIDDEN(hidden_item);
 237                         break;
 238
 239                 case ICAP_REQMOD:
 240                         hidden_item = proto_tree_add_boolean(icap_tree,
 241                                             hf_icap_reqmod, tvb, 0, 0, 1);
 242                         PROTO_ITEM_SET_HIDDEN(hidden_item);
 243                         break;
 244
 245                 case ICAP_RESPMOD:
 246                         hidden_item = proto_tree_add_boolean(icap_tree,
 247                                             hf_icap_respmod, tvb, 0, 0, 1);
 248                         PROTO_ITEM_SET_HIDDEN(hidden_item);
 249                         break;
 250
 251                 case ICAP_RESPONSE:
 252                         hidden_item = proto_tree_add_boolean(icap_tree,
 253                                             hf_icap_response, tvb, 0, 0, 1);
 254                         PROTO_ITEM_SET_HIDDEN(hidden_item);
 255                         break;
 256
 257                 case ICAP_OTHER:
 258                 default:
 259                         break;
 260                 }
 261         }
 262
 263         datalen = tvb_length_remaining(tvb, offset);
 264         if (datalen > 0) {
 265                 call_dissector(data_handle,
 266                     tvb_new_subset(tvb, offset, -1, -1), pinfo, icap_tree);
 267         }
 268 }
 269
 270
 271 static int
 272 is_icap_message(const guchar *data, int linelen, icap_type_t *type)
 273 {
 274 #define ICAP_COMPARE(string, length, msgtype) {         \
 275         if (strncmp(data, string, length) == 0) {       \
 276                 if (*type == ICAP_OTHER)                \
 277                         *type = msgtype;                \
 278                 return TRUE;                            \
 279         }                                               \
 280 }
 281         /*
 282          * From draft-elson-opes-icap-01(72).txt
 283          */
 284         if (linelen >= 5) {
 285                 ICAP_COMPARE("ICAP/", 5, ICAP_RESPONSE); /* response */
 286         }
 287         if (linelen >= 7) {
 288                 ICAP_COMPARE("REQMOD ", 7, ICAP_REQMOD); /* request mod */
 289         }
 290         if (linelen >= 8) {
 291                 ICAP_COMPARE("OPTIONS ", 8, ICAP_OPTIONS); /* options */
 292                 ICAP_COMPARE("RESPMOD ", 8, ICAP_RESPMOD); /* response mod */
 293         }
 294         return FALSE;
 295 #undef ICAP_COMPARE
 296 }
 297
 298 void
 299 proto_register_icap(void)
 300 {
 301         static hf_register_info hf[] = {
 302             { &hf_icap_response,
 303               { "Response",             "icap.response",
 304                 FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 305                 "TRUE if ICAP response", HFILL }},
 306             { &hf_icap_reqmod,
 307               { "Reqmod",               "icap.reqmod",
 308                 FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 309                 "TRUE if ICAP reqmod", HFILL }},
 310             { &hf_icap_respmod,
 311               { "Respmod",              "icap.respmod",
 312                 FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 313                 "TRUE if ICAP respmod", HFILL }},
 314             { &hf_icap_options,
 315               { "Options",              "icap.options",
 316                 FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 317                 "TRUE if ICAP options", HFILL }},
 318             { &hf_icap_other,
 319               { "Other",                "icap.other",
 320                 FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 321                 "TRUE if ICAP other", HFILL }},
 322         };
 323         static gint *ett[] = {
 324                 &ett_icap,
 325         };
 326
 327         proto_icap = proto_register_protocol(
 328                         "Internet Content Adaptation Protocol",
 329                         "ICAP", "icap");
 330         proto_register_field_array(proto_icap, hf, array_length(hf));
 331         proto_register_subtree_array(ett, array_length(ett));
 332
 333 }
 334
 335 void
 336 proto_reg_handoff_icap(void)
 337 {
 338         dissector_handle_t icap_handle;
 339
 340         data_handle = find_dissector("data");
 341         icap_handle = create_dissector_handle(dissect_icap, proto_icap);
 342         dissector_add("tcp.port", TCP_PORT_ICAP, icap_handle);
 343 }