/* packet-imap.c
 * Routines for imap packet dissection
 * Copyright 1999, Richard Sharpe <rsharpe@ns.aus.com>
 *
 * $Id$
 *
 * 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 <epan/wmem/wmem.h>
#include "packet-ssl.h"

#include <stdio.h>
#include <ctype.h>

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] = 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] = 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] = 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);
}
