eb2d6593dc
arguments to "proto_tree_add_text()", and to "proto_tree_add_XXX()" calls that add FT_NONE or FT_PROTO items to the protocol tree, with -1. Replace some calls to "tvb_length()" or "tvb_length_remaining()" with calls to "tvb_reported_length()" and "tvb_reported_length_remaining()", as those give the actual length of the data in the packet, not just the data that happened to be captured. svn path=/trunk/; revision=4605
441 lines
11 KiB
C
441 lines
11 KiB
C
/* packet-telnet.c
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* Routines for telnet packet dissection
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* Copyright 1999, Richard Sharpe <rsharpe@ns.aus.com>
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*
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* $Id: packet-telnet.c,v 1.29 2002/01/24 09:20:52 guy Exp $
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@ethereal.com>
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* Copyright 1998 Gerald Combs
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*
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* Copied from packet-pop.c
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <stdio.h>
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#ifdef HAVE_SYS_TYPES_H
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# include <sys/types.h>
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#endif
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#ifdef HAVE_NETINET_IN_H
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# include <netinet/in.h>
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#endif
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#include <string.h>
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#include <glib.h>
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#include <epan/packet.h>
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#include <epan/strutil.h>
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static int proto_telnet = -1;
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static gint ett_telnet = -1;
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static gint ett_telnet_subopt = -1;
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/* Some defines for Telnet */
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#define TCP_PORT_TELNET 23
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#define TN_IAC 255
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#define TN_DONT 254
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#define TN_DO 253
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#define TN_WONT 252
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#define TN_WILL 251
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#define TN_SB 250
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#define TN_GA 249
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#define TN_EL 248
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#define TN_EC 247
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#define TN_AYT 246
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#define TN_AO 245
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#define TN_IP 244
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#define TN_BRK 243
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#define TN_DM 242
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#define TN_NOP 241
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#define TN_SE 240
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#define TN_EOR 239
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#define TN_ABORT 238
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#define TN_SUSP 237
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#define TN_EOF 236
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static const char *options[] = {
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"Binary Transmission",
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"Echo",
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"Reconnection",
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"Suppress Go Ahead",
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"Approx Message Size Negotiation",
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"Status",
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"Timing Mark",
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"Remote Controlled Trans and Echo",
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"Output Line Width",
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"Output Page Size",
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"Output Carriage-Return Disposition",
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"Output Horizontal Tab Stops",
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"Output Horizontal Tab Disposition",
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"Output Formfeed Disposition",
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"Output Vertical Tabstops",
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"Output Vertical Tab Disposition",
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"Output Linefeed Disposition",
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"Extended ASCII",
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"Logout",
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"Byte Macro",
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"Data Entry Terminal",
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"SUPDUP",
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"SUPDUP Output",
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"Send Location",
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"Terminal Type",
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"End of Record",
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"TACACS User Identification",
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"Output Marking",
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"Terminal Location Number",
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"Telnet 3270 Regime",
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"X.3 PAD",
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"Negotiate About Window Size",
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"Terminal Speed",
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"Remote Flow Control",
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"Linemode",
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"X Display Location",
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"Environment Option",
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"Authentication Option",
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"Encryption Option",
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"New Environment Option",
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"TN3270E"
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};
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#define NOPTIONS (sizeof options / sizeof options[0])
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static int
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telnet_sub_option(proto_tree *telnet_tree, tvbuff_t *tvb, int start_offset)
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{
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proto_tree *ti, *option_tree;
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int offset = start_offset;
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guint8 opt_byte;
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int subneg_len, req;
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const u_char *opt;
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guint len;
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offset += 2; /* skip IAC and SB */
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/* Figure out the option and type */
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opt_byte = tvb_get_guint8(tvb, offset);
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if (opt_byte > NOPTIONS)
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opt = "<unknown option>";
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else
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opt = options[opt_byte];
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offset++;
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req = tvb_get_guint8(tvb, offset);
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offset++;
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/* Search for an IAC. */
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len = tvb_length_remaining(tvb, offset);
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offset = tvb_find_guint8(tvb, offset, len, TN_IAC);
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if (offset == -1) {
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/* None found - run to the end of the packet. */
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offset += len;
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}
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subneg_len = offset - start_offset;
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if (subneg_len > 0) {
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ti = proto_tree_add_text(telnet_tree, tvb, start_offset, subneg_len,
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"Suboption Begin: %s", opt);
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option_tree = proto_item_add_subtree(ti, ett_telnet_subopt);
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proto_tree_add_text(option_tree, tvb, start_offset + 2, 2,
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"%s %s", (req ? "Send your" : "Here's my"), opt);
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if (req == 0) { /* Add the value */
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proto_tree_add_text(option_tree, tvb, start_offset + 4, subneg_len - 4,
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"Value: %s", tvb_format_text(tvb, start_offset + 4, subneg_len - 4));
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}
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}
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return offset;
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}
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static int
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telnet_will_wont_do_dont(proto_tree *telnet_tree, tvbuff_t *tvb,
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int start_offset, char *type)
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{
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int offset = start_offset;
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guint8 opt_byte;
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const char *opt;
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offset += 2; /* skip IAC and WILL,WONT,DO,DONT} */
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opt_byte = tvb_get_guint8(tvb, offset);
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if (opt_byte > NOPTIONS)
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opt = "<unknown option>";
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else
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opt = options[opt_byte];
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offset++;
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proto_tree_add_text(telnet_tree, tvb, start_offset, 3,
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"Command: %s %s", type, opt);
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return offset;
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}
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static int
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telnet_command(proto_tree *telnet_tree, tvbuff_t *tvb, int start_offset)
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{
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int offset = start_offset;
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u_char optcode;
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offset += 1; /* skip IAC */
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optcode = tvb_get_guint8(tvb, offset);
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offset++;
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switch(optcode) {
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case TN_EOF:
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proto_tree_add_text(telnet_tree, tvb, start_offset, 2,
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"Command: End of File");
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break;
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case TN_SUSP:
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proto_tree_add_text(telnet_tree, tvb, start_offset, 2,
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"Command: Suspend Current Process");
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break;
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case TN_ABORT:
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proto_tree_add_text(telnet_tree, tvb, start_offset, 2,
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"Command: Abort Process");
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break;
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case TN_EOR:
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proto_tree_add_text(telnet_tree, tvb, start_offset, 2,
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"Command: End of Record");
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break;
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case TN_SE:
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proto_tree_add_text(telnet_tree, tvb, start_offset, 2,
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"Command: Suboption End");
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break;
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case TN_NOP:
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proto_tree_add_text(telnet_tree, tvb, start_offset, 2,
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"Command: No Operation");
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break;
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case TN_DM:
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proto_tree_add_text(telnet_tree, tvb, start_offset, 2,
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"Command: Data Mark");
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break;
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case TN_BRK:
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proto_tree_add_text(telnet_tree, tvb, start_offset, 2,
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"Command: Break");
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break;
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case TN_IP:
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proto_tree_add_text(telnet_tree, tvb, start_offset, 2,
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"Command: Interrupt Process");
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break;
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case TN_AO:
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proto_tree_add_text(telnet_tree, tvb, start_offset, 2,
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"Command: Abort Output");
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break;
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case TN_AYT:
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proto_tree_add_text(telnet_tree, tvb, start_offset, 2,
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"Command: Are You There?");
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break;
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case TN_EC:
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proto_tree_add_text(telnet_tree, tvb, start_offset, 2,
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"Command: Escape Character");
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break;
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case TN_EL:
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proto_tree_add_text(telnet_tree, tvb, start_offset, 2,
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"Command: Erase Line");
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break;
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case TN_GA:
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proto_tree_add_text(telnet_tree, tvb, start_offset, 2,
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"Command: Go Ahead");
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break;
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case TN_SB:
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offset = telnet_sub_option(telnet_tree, tvb, start_offset);
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break;
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case TN_WILL:
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offset = telnet_will_wont_do_dont(telnet_tree, tvb, start_offset,
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"Will");
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break;
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case TN_WONT:
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offset = telnet_will_wont_do_dont(telnet_tree, tvb, start_offset,
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"Won't");
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break;
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case TN_DO:
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offset = telnet_will_wont_do_dont(telnet_tree, tvb, start_offset,
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"Do");
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break;
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case TN_DONT:
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offset = telnet_will_wont_do_dont(telnet_tree, tvb, start_offset,
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"Don't");
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break;
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}
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return offset;
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}
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static void
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telnet_add_text(proto_tree *tree, tvbuff_t *tvb, int offset, int len)
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{
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gint next_offset;
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int linelen;
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guint8 c;
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gboolean last_char_was_cr;
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while (len != 0 && tvb_offset_exists(tvb, offset)) {
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/*
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* Find the end of the line.
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*/
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linelen = tvb_find_line_end(tvb, offset, len, &next_offset);
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len -= next_offset - offset; /* subtract out the line's characters */
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/*
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* In Telnet, CR NUL is the way you send a CR by itself in the
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* default ASCII mode; don't treat CR by itself as a line ending,
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* treat only CR NUL, CR LF, or LF by itself as a line ending.
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*/
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if (next_offset == offset + linelen + 1 && len >= 1) {
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/*
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* Well, we saw a one-character line ending, so either it's a CR
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* or an LF; we have at least two characters left, including the
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* CR.
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*
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* If the line ending is a CR, skip all subsequent CRs; at
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* least one capture appeared to have multiple CRs at the end of
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* a line.
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*/
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if (tvb_get_guint8(tvb, offset + linelen) == '\r') {
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last_char_was_cr = TRUE;
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while (len != 0 && tvb_offset_exists(tvb, next_offset)) {
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c = tvb_get_guint8(tvb, next_offset);
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next_offset++; /* skip over that character */
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len--;
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if (c == '\n' || (c == '\0' && last_char_was_cr)) {
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/*
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* LF is a line ending, whether preceded by CR or not.
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* NUL is a line ending if preceded by CR.
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*/
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break;
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}
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last_char_was_cr = (c == '\r');
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}
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}
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}
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/*
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* Now compute the length of the line *including* the end-of-line
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* indication, if any; we display it all.
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*/
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linelen = next_offset - offset;
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proto_tree_add_text(tree, tvb, offset, linelen,
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"Data: %s",
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tvb_format_text(tvb, offset, linelen));
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offset = next_offset;
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}
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}
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static void
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dissect_telnet(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_tree *telnet_tree, *ti;
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if (check_col(pinfo->cinfo, COL_PROTOCOL))
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "TELNET");
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if (check_col(pinfo->cinfo, COL_INFO))
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col_add_fstr(pinfo->cinfo, COL_INFO, "Telnet Data ...");
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if (tree) {
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gint offset = 0;
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guint len;
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int data_len;
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gint iac_offset;
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ti = proto_tree_add_item(tree, proto_telnet, tvb, offset, -1, FALSE);
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telnet_tree = proto_item_add_subtree(ti, ett_telnet);
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/*
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* Scan through the buffer looking for an IAC byte.
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*/
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while ((len = tvb_length_remaining(tvb, offset)) > 0) {
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iac_offset = tvb_find_guint8(tvb, offset, len, TN_IAC);
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if (iac_offset != -1) {
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/*
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* We found an IAC byte.
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* If there's any data before it, add that data to the
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* tree, a line at a time.
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*/
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data_len = iac_offset - offset;
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if (data_len > 0)
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telnet_add_text(telnet_tree, tvb, offset, data_len);
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/*
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* Now interpret the command.
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*/
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offset = telnet_command(telnet_tree, tvb, iac_offset);
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}
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else {
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/*
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* We found no IAC byte, so what remains in the buffer
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* is the last of the data in the packet.
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* Add it to the tree, a line at a time, and then quit.
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*/
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telnet_add_text(telnet_tree, tvb, offset, len);
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break;
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}
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}
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}
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}
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void
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proto_register_telnet(void)
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{
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/* static hf_register_info hf[] = {
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{ &variable,
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{ "Name", "telnet.abbreviation", TYPE, VALS_POINTER }},
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};*/
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static gint *ett[] = {
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&ett_telnet,
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&ett_telnet_subopt,
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};
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proto_telnet = proto_register_protocol("Telnet", "TELNET", "telnet");
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/* proto_register_field_array(proto_telnet, hf, array_length(hf));*/
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proto_register_subtree_array(ett, array_length(ett));
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}
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void
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proto_reg_handoff_telnet(void)
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{
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dissector_handle_t telnet_handle;
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telnet_handle = create_dissector_handle(dissect_telnet, proto_telnet);
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dissector_add("tcp.port", TCP_PORT_TELNET, telnet_handle);
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}
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