/* packet-imap.c
 * Routines for imap packet dissection
 * Copyright 1999, Richard Sharpe <rsharpe@ns.aus.com>
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * Copied from packet-tftp.c
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"


#include <epan/packet.h>
#include <epan/strutil.h>
#include "packet-ssl.h"

void proto_register_imap(void);
void proto_reg_handoff_imap(void);

static int proto_imap = -1;
static int hf_imap_isrequest = -1;
static int hf_imap_line = -1;
static int hf_imap_request = -1;
static int hf_imap_request_tag = -1;
static int hf_imap_response = -1;
static int hf_imap_response_tag = -1;
static int hf_imap_request_command = -1;
static int hf_imap_response_status = -1;
static int hf_imap_request_folder = -1;
static int hf_imap_request_uid = -1;

static gint ett_imap = -1;
static gint ett_imap_reqresp = -1;

static dissector_handle_t imap_handle;

#define TCP_PORT_IMAP     143
#define TCP_PORT_SSL_IMAP 993
#define MAX_BUFFER        1024

static void
dissect_imap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
  gboolean        is_request;
  proto_tree      *imap_tree, *reqresp_tree;
  proto_item      *ti, *hidden_item;
  gint            offset = 0;
  gint            uid_offset = 0;
  gint            folder_offset = 0;
  const guchar    *line;
  const guchar    *uid_line;
  const guchar    *folder_line;
  gint            next_offset;
  int             linelen;
  int             tokenlen;
  int             uid_tokenlen;
  int             folder_tokenlen;
  const guchar    *next_token;
  const guchar    *uid_next_token;
  const guchar    *folder_next_token;
  guchar          *tokenbuf;
  guchar          *command_token;
  int             iter;
  int             commandlen;

  tokenbuf = (guchar *)wmem_alloc(wmem_packet_scope(), MAX_BUFFER);
  command_token = (guchar *)wmem_alloc(wmem_packet_scope(), MAX_BUFFER);
  memset(tokenbuf, '\0', MAX_BUFFER);
  memset(command_token, '\0', MAX_BUFFER);
  commandlen = 0;
  folder_offset = 0;
  folder_tokenlen = 0;
  folder_line = NULL;
  col_set_str(pinfo->cinfo, COL_PROTOCOL, "IMAP");


  if (pinfo->match_uint == pinfo->destport)
    is_request = TRUE;
  else
    is_request = FALSE;

  /*
   * Put the first line from the buffer into the summary
   * (but leave out the line terminator).
   */
  linelen = tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);
  line = tvb_get_ptr(tvb, offset, linelen);

  col_add_fstr(pinfo->cinfo, COL_INFO, "%s: %s", is_request ? "Request" : "Response", format_text(line, linelen));

  if (tree) {
    ti = proto_tree_add_item(tree, proto_imap, tvb, offset, -1, ENC_NA);
    imap_tree = proto_item_add_subtree(ti, ett_imap);

    hidden_item = proto_tree_add_boolean(imap_tree, hf_imap_isrequest, tvb, 0, 0, is_request);
    PROTO_ITEM_SET_HIDDEN(hidden_item);

    while(tvb_length_remaining(tvb, offset) > 0) {

      /*
       * Find the end of each line
       *
       * Note that "tvb_find_line_end()" will return a value that is
       * not longer than what's in the buffer, so the "tvb_get_ptr()"
       * call won't throw an exception.
       */
      linelen = tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);
      line = tvb_get_ptr(tvb, offset, linelen);

      /*
       * Put the line into the protocol tree.
       */
      ti = proto_tree_add_item(imap_tree, hf_imap_line, tvb, offset, next_offset - offset, ENC_ASCII|ENC_NA);

      reqresp_tree = proto_item_add_subtree(ti, ett_imap_reqresp);

      /*
       * Check that the line doesn't begin with '*', because that's a continuation line.
       * Otherwise if a tag is present then extract tokens.
       */
      if ( (line) && ((line[0] != '*') || (TRUE == is_request)) ) {
        /*
         * Show each line as tags + requests or replies.
         */

        /*
         * Extract the first token, and, if there is a first
         * token, add it as the request or reply tag.
         */
        tokenlen = get_token_len(line, line + linelen, &next_token);
        if (tokenlen != 0) {
          proto_tree_add_item(reqresp_tree, (is_request) ? hf_imap_request_tag : hf_imap_response_tag, tvb, offset, tokenlen, ENC_ASCII|ENC_NA);

          offset += (gint) (next_token - line);
          linelen -= (int) (next_token - line);
          line = next_token;
        }

        /*
         * Extract second token, and, if there is a second
         * token, and it's not uid, add it as the request or reply command.
         */
        tokenlen = get_token_len(line, line + linelen, &next_token);
        if (tokenlen != 0) {
          for (iter = 0; iter < tokenlen && iter < MAX_BUFFER-1; iter++) {
            tokenbuf[iter] = g_ascii_tolower(line[iter]);
          }
          if ( TRUE == is_request && strncmp(tokenbuf,"uid",tokenlen) == 0) {
            proto_tree_add_item(reqresp_tree, hf_imap_request_uid, tvb, offset, tokenlen, ENC_ASCII|ENC_NA);
            /*
             * UID is a precursor to a command, if following the tag,
              * so move to next token to grab the actual command.
              */
            uid_offset = offset;
            uid_offset += (gint) (next_token - line);
            uid_line = next_token;
            uid_tokenlen = get_token_len(uid_line, uid_line + (linelen - tokenlen), &uid_next_token);
            if (tokenlen != 0) {
              proto_tree_add_item(reqresp_tree, hf_imap_request_command, tvb, uid_offset, uid_tokenlen, ENC_ASCII|ENC_NA);

              /*
               * Save command string to do specialized processing.
               */
              for (iter = 0; iter < uid_tokenlen && iter < MAX_BUFFER-1; iter++) {
                command_token[iter] = g_ascii_tolower(uid_line[iter]);
              }
              commandlen = uid_tokenlen;

              folder_offset = uid_offset;
              folder_offset += (gint) (uid_next_token - uid_line);
              folder_line = uid_next_token;
              folder_tokenlen = get_token_len(folder_line, folder_line + (linelen - tokenlen - uid_tokenlen), &folder_next_token);
            }
          } else {
            /*
             * Not a UID request so perform normal parsing.
             */
            proto_tree_add_item(reqresp_tree, (is_request) ? hf_imap_request_command : hf_imap_response_status, tvb, offset, tokenlen, ENC_ASCII|ENC_NA);

            if (is_request) {
              /*
               * Save command string to do specialized processing.
               */
              for (iter = 0; iter < tokenlen && iter < 256; iter++) {
                command_token[iter] = g_ascii_tolower(line[iter]);
              }
              commandlen = tokenlen;

              folder_offset = offset;
              folder_offset += (gint) (next_token - line);
              folder_line = next_token;
              folder_tokenlen = get_token_len(folder_line, folder_line + (linelen - tokenlen - 1), &folder_next_token);
            }
          }

          if (commandlen > 0 && (
              strncmp(command_token, "select", commandlen) == 0 ||
              strncmp(command_token, "examine", commandlen) == 0 ||
              strncmp(command_token, "create", commandlen) == 0 ||
              strncmp(command_token, "delete", commandlen) == 0 ||
              strncmp(command_token, "rename", commandlen) == 0 ||
              strncmp(command_token, "subscribe", commandlen) == 0 ||
              strncmp(command_token, "unsubscribe", commandlen) == 0 ||
              strncmp(command_token, "status", commandlen) == 0 ||
              strncmp(command_token, "append", commandlen) == 0 ||
              strncmp(command_token, "search", commandlen) == 0)) {
            /*
             * These commands support folder as an argument,
             * so parse out the folder name.
             */
            if (folder_tokenlen != 0)
              proto_tree_add_item(reqresp_tree, hf_imap_request_folder, tvb, folder_offset, folder_tokenlen, ENC_ASCII|ENC_NA);
          }

          if ( is_request && (NULL != folder_line) && strncmp(command_token, "copy", commandlen) == 0) {
            /*
             * Handle the copy command separately since folder
             * is the second argument for this command.
             */
            folder_offset += (gint) (folder_next_token - folder_line);
            folder_line = folder_next_token;
            folder_tokenlen = get_token_len(folder_line, folder_line + (linelen - tokenlen), &folder_next_token);

            if (folder_tokenlen != 0)
              proto_tree_add_item(reqresp_tree, hf_imap_request_folder, tvb, folder_offset, folder_tokenlen, ENC_ASCII|ENC_NA);
          }

        }

        /*
         * Add the rest of the line as request or reply data.
         */
        if (linelen != 0) {
          proto_tree_add_item(reqresp_tree, (is_request) ? hf_imap_request : hf_imap_response, tvb, offset, linelen, ENC_ASCII|ENC_NA);
        }

      }

      offset = next_offset; /* Skip over last line and \r\n at the end of it */
    }
  }
}

void
proto_register_imap(void)
{
  static hf_register_info hf[] = {

    { &hf_imap_isrequest,
      { "Request", "imap.isrequest",
         FT_BOOLEAN, BASE_NONE, NULL, 0x0,
         "TRUE if IMAP request, FALSE otherwise", HFILL }
    },
    { &hf_imap_line,
      { "Line", "imap.line",
        FT_STRINGZ, BASE_NONE, NULL, 0x0,
        "A line of an IMAP message", HFILL }
    },
    { &hf_imap_request,
      { "Request", "imap.request",
        FT_STRINGZ, BASE_NONE, NULL, 0x0,
        "Remainder of request line", HFILL }
    },
    { &hf_imap_request_tag,
      { "Request Tag", "imap.request_tag",
        FT_STRINGZ, BASE_NONE, NULL, 0x0,
        "First token of request line", HFILL }
    },
    { &hf_imap_response,
      { "Response", "imap.response",
        FT_STRINGZ, BASE_NONE, NULL, 0x0,
        "Remainder of response line", HFILL }
    },
    { &hf_imap_response_tag,
      { "Response Tag", "imap.response_tag",
      FT_STRINGZ, BASE_NONE, NULL, 0x0,
      "First token of response line", HFILL }
    },
    { &hf_imap_request_command,
      { "Request Command", "imap.request.command",
      FT_STRINGZ, BASE_NONE, NULL, 0x0,
      "Request command name", HFILL }
    },
    { &hf_imap_response_status,
      { "Response Status", "imap.response.status",
      FT_STRINGZ, BASE_NONE, NULL, 0x0,
      "Response status code", HFILL }
    },
    { &hf_imap_request_folder,
      { "Request Folder", "imap.request.folder",
        FT_STRINGZ, BASE_NONE, NULL, 0x0,
        "Request command folder", HFILL }
    },
    { &hf_imap_request_uid,
      { "Request isUID", "imap.request.command.uid",
      FT_BOOLEAN, BASE_NONE, NULL, 0x0,
      "Request command uid", HFILL }
    }
  };

  static gint *ett[] = {
  &ett_imap,
  &ett_imap_reqresp,
  };

  proto_imap = proto_register_protocol("Internet Message Access Protocol", "IMAP", "imap");

  imap_handle = register_dissector("imap", dissect_imap, proto_imap);

  proto_register_field_array(proto_imap, hf, array_length(hf));
  proto_register_subtree_array(ett, array_length(ett));
}

void
proto_reg_handoff_imap(void)
{
  dissector_add_uint("tcp.port", TCP_PORT_IMAP, imap_handle);
  ssl_dissector_add(TCP_PORT_SSL_IMAP, "imap", TRUE);
}
/*
 * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 2
 * tab-width: 8
 * indent-tabs-mode: nil
 * End:
 *
 * vi: set shiftwidth=2 tabstop=8 expandtab:
 * :indentSize=2:tabSize=8:noTabs=true
 */