![Ronnie Sahlberg](/assets/img/avatar_default.png)
windows in SYN and SYN+ACK packets are not scaled so dont apply window scaling to them when displaying them in the tree svn path=/trunk/; revision=19186
2904 lines
96 KiB
C
2904 lines
96 KiB
C
/* packet-tcp.c
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* Routines for TCP packet disassembly
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*
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* $Id$
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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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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#include <string.h>
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#include <glib.h>
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#include <epan/in_cksum.h>
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#include <epan/packet.h>
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#include <epan/addr_resolv.h>
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#include <epan/ipproto.h>
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#include <epan/ip_opts.h>
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#include <epan/follow.h>
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#include <epan/prefs.h>
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#include <epan/emem.h>
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#include "packet-tcp.h"
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#include "packet-ip.h"
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#include "packet-frame.h"
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#include <epan/conversation.h>
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#include <epan/strutil.h>
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#include <epan/reassemble.h>
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#include <epan/tap.h>
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#include <epan/slab.h>
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#include <epan/expert.h>
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static int tcp_tap = -1;
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/* Place TCP summary in proto tree */
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static gboolean tcp_summary_in_tree = TRUE;
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/*
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* Flag to control whether to check the TCP checksum.
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*
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* In at least some Solaris network traces, there are packets with bad
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* TCP checksums, but the traffic appears to indicate that the packets
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* *were* received; the packets were probably sent by the host on which
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* the capture was being done, on a network interface to which
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* checksumming was offloaded, so that DLPI supplied an un-checksummed
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* packet to the capture program but a checksummed packet got put onto
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* the wire.
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*/
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static gboolean tcp_check_checksum = TRUE;
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extern FILE* data_out_file;
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static int proto_tcp = -1;
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static int hf_tcp_srcport = -1;
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static int hf_tcp_dstport = -1;
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static int hf_tcp_port = -1;
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static int hf_tcp_seq = -1;
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static int hf_tcp_nxtseq = -1;
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static int hf_tcp_ack = -1;
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static int hf_tcp_hdr_len = -1;
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static int hf_tcp_flags = -1;
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static int hf_tcp_flags_cwr = -1;
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static int hf_tcp_flags_ecn = -1;
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static int hf_tcp_flags_urg = -1;
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static int hf_tcp_flags_ack = -1;
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static int hf_tcp_flags_push = -1;
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static int hf_tcp_flags_reset = -1;
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static int hf_tcp_flags_syn = -1;
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static int hf_tcp_flags_fin = -1;
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static int hf_tcp_window_size = -1;
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static int hf_tcp_checksum = -1;
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static int hf_tcp_checksum_bad = -1;
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static int hf_tcp_len = -1;
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static int hf_tcp_urgent_pointer = -1;
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static int hf_tcp_analysis_flags = -1;
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static int hf_tcp_analysis_acks_frame = -1;
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static int hf_tcp_analysis_ack_rtt = -1;
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static int hf_tcp_analysis_rto = -1;
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static int hf_tcp_analysis_rto_frame = -1;
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static int hf_tcp_analysis_retransmission = -1;
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static int hf_tcp_analysis_fast_retransmission = -1;
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static int hf_tcp_analysis_out_of_order = -1;
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static int hf_tcp_analysis_lost_packet = -1;
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static int hf_tcp_analysis_ack_lost_packet = -1;
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static int hf_tcp_analysis_window_update = -1;
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static int hf_tcp_analysis_window_full = -1;
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static int hf_tcp_analysis_keep_alive = -1;
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static int hf_tcp_analysis_keep_alive_ack = -1;
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static int hf_tcp_analysis_duplicate_ack = -1;
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static int hf_tcp_analysis_duplicate_ack_num = -1;
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static int hf_tcp_analysis_duplicate_ack_frame = -1;
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static int hf_tcp_analysis_zero_window = -1;
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static int hf_tcp_analysis_zero_window_probe = -1;
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static int hf_tcp_analysis_zero_window_probe_ack = -1;
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static int hf_tcp_continuation_to = -1;
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static int hf_tcp_pdu_time = -1;
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static int hf_tcp_pdu_last_frame = -1;
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static int hf_tcp_reassembled_in = -1;
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static int hf_tcp_segments = -1;
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static int hf_tcp_segment = -1;
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static int hf_tcp_segment_overlap = -1;
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static int hf_tcp_segment_overlap_conflict = -1;
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static int hf_tcp_segment_multiple_tails = -1;
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static int hf_tcp_segment_too_long_fragment = -1;
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static int hf_tcp_segment_error = -1;
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static int hf_tcp_option_mss = -1;
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static int hf_tcp_option_mss_val = -1;
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static int hf_tcp_option_wscale = -1;
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static int hf_tcp_option_wscale_val = -1;
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static int hf_tcp_option_sack_perm = -1;
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static int hf_tcp_option_sack = -1;
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static int hf_tcp_option_sack_sle = -1;
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static int hf_tcp_option_sack_sre = -1;
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static int hf_tcp_option_echo = -1;
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static int hf_tcp_option_echo_reply = -1;
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static int hf_tcp_option_time_stamp = -1;
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static int hf_tcp_option_cc = -1;
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static int hf_tcp_option_ccnew = -1;
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static int hf_tcp_option_ccecho = -1;
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static int hf_tcp_option_md5 = -1;
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static gint ett_tcp = -1;
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static gint ett_tcp_flags = -1;
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static gint ett_tcp_options = -1;
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static gint ett_tcp_option_sack = -1;
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static gint ett_tcp_analysis = -1;
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static gint ett_tcp_analysis_faults = -1;
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static gint ett_tcp_segments = -1;
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static gint ett_tcp_segment = -1;
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/* not all of the hf_fields below make sense for TCP but we have to provide
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them anyways to comply with the api (which was aimed for ip fragment
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reassembly) */
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static const fragment_items tcp_segment_items = {
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&ett_tcp_segment,
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&ett_tcp_segments,
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&hf_tcp_segments,
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&hf_tcp_segment,
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&hf_tcp_segment_overlap,
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&hf_tcp_segment_overlap_conflict,
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&hf_tcp_segment_multiple_tails,
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&hf_tcp_segment_too_long_fragment,
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&hf_tcp_segment_error,
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&hf_tcp_reassembled_in,
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"Segments"
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};
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static dissector_table_t subdissector_table;
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static heur_dissector_list_t heur_subdissector_list;
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static dissector_handle_t data_handle;
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/* TCP structs and definitions */
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/* **************************************************************************
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* RTT and reltive sequence numbers.
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* **************************************************************************/
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static gboolean tcp_analyze_seq = TRUE;
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static gboolean tcp_relative_seq = TRUE;
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/* SLAB allocator for tcp_unacked structures
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*/
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SLAB_ITEM_TYPE_DEFINE(tcp_unacked_t)
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static SLAB_FREE_LIST_DEFINE(tcp_unacked_t)
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#define TCP_UNACKED_NEW(fi) \
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SLAB_ALLOC(fi, tcp_unacked_t)
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#define TCP_UNACKED_FREE(fi) \
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SLAB_FREE(fi, tcp_unacked_t)
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/* Idea for gt: either x > y, or y is much bigger (assume wrap) */
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#define GT_SEQ(x, y) ((gint32)((y) - (x)) < 0)
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#define LT_SEQ(x, y) ((gint32)((x) - (y)) < 0)
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#define GE_SEQ(x, y) ((gint32)((y) - (x)) <= 0)
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#define LE_SEQ(x, y) ((gint32)((x) - (y)) <= 0)
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#define EQ_SEQ(x, y) ((x) == (y))
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#define TCP_A_RETRANSMISSION 0x0001
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#define TCP_A_LOST_PACKET 0x0002
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#define TCP_A_ACK_LOST_PACKET 0x0004
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#define TCP_A_KEEP_ALIVE 0x0008
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#define TCP_A_DUPLICATE_ACK 0x0010
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#define TCP_A_ZERO_WINDOW 0x0020
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#define TCP_A_ZERO_WINDOW_PROBE 0x0040
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#define TCP_A_ZERO_WINDOW_PROBE_ACK 0x0080
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#define TCP_A_KEEP_ALIVE_ACK 0x0100
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#define TCP_A_OUT_OF_ORDER 0x0200
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#define TCP_A_FAST_RETRANSMISSION 0x0400
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#define TCP_A_WINDOW_UPDATE 0x0800
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#define TCP_A_WINDOW_FULL 0x1000
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static void
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process_tcp_payload(tvbuff_t *tvb, volatile int offset, packet_info *pinfo,
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proto_tree *tree, proto_tree *tcp_tree, int src_port, int dst_port,
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guint32 seq, guint32 nxtseq, gboolean is_tcp_segment,
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struct tcp_analysis *tcpd);
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struct tcp_analysis *
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get_tcp_conversation_data(packet_info *pinfo)
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{
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int direction;
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conversation_t *conv=NULL;
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struct tcp_analysis *tcpd=NULL;
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/* Have we seen this conversation before? */
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if( (conv=find_conversation(pinfo->fd->num, &pinfo->src, &pinfo->dst, pinfo->ptype, pinfo->srcport, pinfo->destport, 0)) == NULL){
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/* No this is a new conversation. */
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conv=conversation_new(pinfo->fd->num, &pinfo->src, &pinfo->dst, pinfo->ptype, pinfo->srcport, pinfo->destport, 0);
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}
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/* check if we have any data for this conversation */
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tcpd=conversation_get_proto_data(conv, proto_tcp);
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if(!tcpd){
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/* No no such data yet. Allocate and init it */
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tcpd=se_alloc(sizeof(struct tcp_analysis));
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tcpd->flow1.segments=NULL;
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tcpd->flow1.base_seq=0;
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tcpd->flow1.lastack=0;
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tcpd->flow1.lastacktime.secs=0;
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tcpd->flow1.lastacktime.nsecs=0;
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tcpd->flow1.lastnondupack=0;
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tcpd->flow1.nextseq=0;
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tcpd->flow1.nextseqtime.secs=0;
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tcpd->flow1.nextseqtime.nsecs=0;
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tcpd->flow1.nextseqframe=0;
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tcpd->flow1.window=0;
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tcpd->flow1.win_scale=-1;
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tcpd->flow1.flags=0;
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tcpd->flow1.multisegment_pdus=se_tree_create_non_persistent(EMEM_TREE_TYPE_RED_BLACK, "tcp_multisegment_pdus");
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tcpd->flow2.segments=NULL;
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tcpd->flow2.base_seq=0;
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tcpd->flow2.lastack=0;
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tcpd->flow2.lastacktime.secs=0;
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tcpd->flow2.lastacktime.nsecs=0;
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tcpd->flow2.lastnondupack=0;
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tcpd->flow2.nextseq=0;
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tcpd->flow2.nextseqtime.secs=0;
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tcpd->flow2.nextseqtime.nsecs=0;
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tcpd->flow2.nextseqframe=0;
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tcpd->flow2.window=0;
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tcpd->flow2.win_scale=-1;
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tcpd->flow2.flags=0;
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tcpd->flow2.multisegment_pdus=se_tree_create_non_persistent(EMEM_TREE_TYPE_RED_BLACK, "tcp_multisegment_pdus");
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tcpd->acked_table=se_tree_create_non_persistent(EMEM_TREE_TYPE_RED_BLACK, "tcp_analyze_acked_table");
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conversation_add_proto_data(conv, proto_tcp, tcpd);
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}
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/* check direction and get ua lists */
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direction=CMP_ADDRESS(&pinfo->src, &pinfo->dst);
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/* if the addresses are equal, match the ports instead */
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if(direction==0) {
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direction= (pinfo->srcport > pinfo->destport)*2-1;
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}
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if(direction>=0){
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tcpd->fwd=&(tcpd->flow1);
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tcpd->rev=&(tcpd->flow2);
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} else {
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tcpd->fwd=&(tcpd->flow2);
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tcpd->rev=&(tcpd->flow1);
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}
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tcpd->ta=NULL;
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return tcpd;
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}
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static void
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print_pdu_tracking_data(packet_info *pinfo, tvbuff_t *tvb, proto_tree *tcp_tree, struct tcp_multisegment_pdu *msp)
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{
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proto_item *item;
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if (check_col(pinfo->cinfo, COL_INFO)){
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col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[Continuation to #%u] ", msp->first_frame);
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}
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item=proto_tree_add_uint(tcp_tree, hf_tcp_continuation_to,
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tvb, 0, 0, msp->first_frame);
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PROTO_ITEM_SET_GENERATED(item);
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}
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/* if we know that a PDU starts inside this segment, return the adjusted
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offset to where that PDU starts or just return offset back
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and let TCP try to find out what it can about this segment
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*/
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static int
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scan_for_next_pdu(tvbuff_t *tvb, proto_tree *tcp_tree, packet_info *pinfo, int offset, guint32 seq, guint32 nxtseq, struct tcp_analysis *tcpd)
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{
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struct tcp_multisegment_pdu *msp=NULL;
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if(!pinfo->fd->flags.visited){
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msp=se_tree_lookup32_le(tcpd->fwd->multisegment_pdus, seq-1);
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if(msp){
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/* If this segment is completely within a previous PDU
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* then we just skip this packet
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*/
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if(seq>msp->seq && nxtseq<=msp->nxtpdu){
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msp->last_frame=pinfo->fd->num;
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msp->last_frame_time=pinfo->fd->abs_ts;
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print_pdu_tracking_data(pinfo, tvb, tcp_tree, msp);
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return -1;
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}
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if(seq<msp->nxtpdu && nxtseq>msp->nxtpdu){
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offset+=msp->nxtpdu-seq;
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return offset;
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}
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}
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} else {
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msp=se_tree_lookup32_le(tcpd->fwd->multisegment_pdus, seq-1);
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if(msp){
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if(pinfo->fd->num==msp->first_frame){
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proto_item *item;
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nstime_t ns;
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item=proto_tree_add_uint(tcp_tree, hf_tcp_pdu_last_frame, tvb, 0, 0, msp->last_frame);
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PROTO_ITEM_SET_GENERATED(item);
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nstime_delta(&ns, &msp->last_frame_time, &pinfo->fd->abs_ts);
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item = proto_tree_add_time(tcp_tree, hf_tcp_pdu_time,
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tvb, 0, 0, &ns);
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PROTO_ITEM_SET_GENERATED(item);
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}
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/* If this segment is completely within a previous PDU
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* then we just skip this packet
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*/
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if(seq>msp->seq && nxtseq<=msp->nxtpdu){
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print_pdu_tracking_data(pinfo, tvb, tcp_tree, msp);
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return -1;
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}
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if(seq<msp->nxtpdu && nxtseq>msp->nxtpdu){
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offset+=msp->nxtpdu-seq;
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return offset;
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}
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}
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}
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return offset;
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}
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/* if we saw a PDU that extended beyond the end of the segment,
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use this function to remember where the next pdu starts
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*/
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static struct tcp_multisegment_pdu *
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pdu_store_sequencenumber_of_next_pdu(packet_info *pinfo, guint32 seq, guint32 nxtpdu, struct tcp_analysis *tcpd)
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{
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struct tcp_multisegment_pdu *msp;
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msp=se_alloc(sizeof(struct tcp_multisegment_pdu));
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msp->nxtpdu=nxtpdu;
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msp->seq=seq;
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msp->first_frame=pinfo->fd->num;
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msp->last_frame=pinfo->fd->num;
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msp->last_frame_time=pinfo->fd->abs_ts;
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se_tree_insert32(tcpd->fwd->multisegment_pdus, seq, (void *)msp);
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return msp;
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}
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/* This is called for SYN+ACK packets and the purpose is to verify that we
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* have seen window scaling in both directions.
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* If we cant find window scaling being set in both directions
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* that means it was present in the SYN but not in the SYN+ACK
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* (or the SYN was missing) and then we disable the window scaling
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* for this tcp session.
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*/
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static void
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verify_tcp_window_scaling(struct tcp_analysis *tcpd)
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{
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if( tcpd && ((tcpd->flow1.win_scale==-1) || (tcpd->flow2.win_scale==-1)) ){
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tcpd->flow1.win_scale=-1;
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tcpd->flow2.win_scale=-1;
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}
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}
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/* if we saw a window scaling option, store it for future reference
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*/
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static void
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pdu_store_window_scale_option(guint8 ws, struct tcp_analysis *tcpd)
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{
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tcpd->fwd->win_scale=ws;
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}
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static void
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tcp_get_relative_seq_ack(guint32 *seq, guint32 *ack, guint32 *win, struct tcp_analysis *tcpd)
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{
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if(tcp_relative_seq){
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(*seq) -= tcpd->fwd->base_seq;
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(*ack) -= tcpd->rev->base_seq;
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if(tcpd->fwd->win_scale!=-1){
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(*win)<<=tcpd->fwd->win_scale;
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}
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}
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}
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/* when this function returns, it will (if createflag) populate the ta pointer.
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*/
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static void
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tcp_analyze_get_acked_struct(guint32 frame, gboolean createflag, struct tcp_analysis *tcpd)
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{
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tcpd->ta=se_tree_lookup32(tcpd->acked_table, frame);
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if((!tcpd->ta) && createflag){
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tcpd->ta=se_alloc(sizeof(struct tcp_acked));
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tcpd->ta->frame_acked=0;
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tcpd->ta->ts.secs=0;
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|
tcpd->ta->ts.nsecs=0;
|
|
tcpd->ta->flags=0;
|
|
tcpd->ta->dupack_num=0;
|
|
tcpd->ta->dupack_frame=0;
|
|
se_tree_insert32(tcpd->acked_table, frame, (void *)tcpd->ta);
|
|
}
|
|
}
|
|
|
|
|
|
/* fwd contains a list of all segments processed but not yet ACKed in the
|
|
* same direction as the current segment.
|
|
* rev contains a list of all segments received but not yet ACKed in the
|
|
* opposite direction to the current segment.
|
|
*
|
|
* New segments are always added to the head of the fwd/rev lists.
|
|
*
|
|
*/
|
|
static void
|
|
tcp_analyze_sequence_number(packet_info *pinfo, guint32 seq, guint32 ack, guint32 seglen, guint8 flags, guint32 window, struct tcp_analysis *tcpd)
|
|
{
|
|
tcp_unacked_t *ual=NULL;
|
|
int ackcount;
|
|
|
|
#ifdef REMOVED
|
|
printf("analyze_sequence numbers frame:%d direction:%s\n",pinfo->fd->num,direction>=0?"FWD":"REW");
|
|
printf("FWD list lastflags:0x%04x base_seq:0x%08x:\n",tcpd->fwd->lastsegmentflags,tcpd->fwd->base_seq);for(ual=tcpd->fwd->segments;ual;ual=ual->next)printf("Frame:%d Seq:%d Nextseq:%d\n",ual->frame,ual->seq,ual->nextseq);
|
|
printf("REV list lastflags:0x%04x base_seq:0x%08x:\n",tcpd->rev->lastsegmentflags,tcpd->rev->base_seq);for(ual=tcpd->rev->segments;ual;ual=ual->next)printf("Frame:%d Seq:%d Nextseq:%d\n",ual->frame,ual->seq,ual->nextseq);
|
|
#endif
|
|
|
|
|
|
|
|
/* if this is the first segment for this list we need to store the
|
|
* base_seq
|
|
*/
|
|
if(tcpd->fwd->base_seq==0){
|
|
tcpd->fwd->base_seq=seq;
|
|
}
|
|
/* if we have spotted a new base_Seq in the reverse direction
|
|
* store it.
|
|
*/
|
|
if(tcpd->rev->base_seq==0){
|
|
tcpd->rev->base_seq=ack;
|
|
}
|
|
|
|
|
|
|
|
/* ZERO WINDOW PROBE
|
|
* it is a zero window probe if
|
|
* the sequnece number is the next expected one
|
|
* the window in the other direction is 0
|
|
* the segment is exactly 1 byte
|
|
*/
|
|
/*QQQ tested*/
|
|
if( seglen==1
|
|
&& seq==tcpd->fwd->nextseq
|
|
&& tcpd->rev->window==0 ){
|
|
if(!tcpd->ta){
|
|
tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE, tcpd);
|
|
}
|
|
tcpd->ta->flags|=TCP_A_ZERO_WINDOW_PROBE;
|
|
goto finished_fwd;
|
|
}
|
|
|
|
|
|
/* ZERO WINDOW
|
|
* a zero window packet has window == 0 but none of the SYN/FIN/RST set
|
|
*/
|
|
/*QQQ tested*/
|
|
if( window==0
|
|
&& (flags&(TH_RST|TH_FIN|TH_SYN))==0 ){
|
|
if(!tcpd->ta){
|
|
tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE, tcpd);
|
|
}
|
|
tcpd->ta->flags|=TCP_A_ZERO_WINDOW;
|
|
}
|
|
|
|
|
|
/* LOST PACKET
|
|
* If this segment is beyond the last seen nextseq we must
|
|
* have missed some previous segment
|
|
*
|
|
* We only check for this if we have actually seen segments prior to this
|
|
* one.
|
|
* RST packets are not checked for this.
|
|
*/
|
|
if( tcpd->fwd->nextseq
|
|
&& GT_SEQ(seq, tcpd->fwd->nextseq)
|
|
&& (flags&(TH_RST))==0 ){
|
|
if(!tcpd->ta){
|
|
tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE, tcpd);
|
|
}
|
|
tcpd->ta->flags|=TCP_A_LOST_PACKET;
|
|
}
|
|
|
|
|
|
/* KEEP ALIVE
|
|
* a keepalive contains 0 or 1 bytes of data and starts one byte prior
|
|
* to what should be the next sequence number.
|
|
* SYN/FIN/RST segments are never keepalives
|
|
*/
|
|
/*QQQ tested */
|
|
if( (seglen==0||seglen==1)
|
|
&& seq==(tcpd->fwd->nextseq-1)
|
|
&& (flags&(TH_SYN|TH_FIN|TH_RST))==0 ){
|
|
if(!tcpd->ta){
|
|
tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE, tcpd);
|
|
}
|
|
tcpd->ta->flags|=TCP_A_KEEP_ALIVE;
|
|
}
|
|
|
|
/* WINDOW UPDATE
|
|
* A window update is a 0 byte segment with the same SEQ/ACK numbers as
|
|
* the previous seen segment and with a new window value
|
|
*/
|
|
if( seglen==0
|
|
&& window
|
|
&& window!=tcpd->fwd->window
|
|
&& seq==tcpd->fwd->nextseq
|
|
&& ack==tcpd->fwd->lastack
|
|
&& (flags&(TH_SYN|TH_FIN|TH_RST))==0 ){
|
|
if(!tcpd->ta){
|
|
tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE, tcpd);
|
|
}
|
|
tcpd->ta->flags|=TCP_A_WINDOW_UPDATE;
|
|
}
|
|
|
|
|
|
/* WINDOW FULL
|
|
* If we know the window scaling
|
|
* and if this segment contains data ang goes all the way to the
|
|
* edge of the advertized window
|
|
* then we mark it as WINDOW FULL
|
|
* SYN/RST/FIN packets are never WINDOW FULL
|
|
*/
|
|
/*QQQ tested*/
|
|
if( seglen>0
|
|
&& tcpd->fwd->win_scale!=-1
|
|
&& tcpd->rev->win_scale!=-1
|
|
&& (seq+seglen)==(tcpd->rev->lastack+(tcpd->rev->window<<tcpd->rev->win_scale))
|
|
&& (flags&(TH_SYN|TH_FIN|TH_RST))==0 ){
|
|
if(!tcpd->ta){
|
|
tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE, tcpd);
|
|
}
|
|
tcpd->ta->flags|=TCP_A_WINDOW_FULL;
|
|
}
|
|
|
|
|
|
/* KEEP ALIVE ACK
|
|
* It is a keepalive ack if it repeats the previous ACK and if
|
|
* the last segment in the reverse direction was a keepalive
|
|
*/
|
|
/*QQQ tested*/
|
|
if( seglen==0
|
|
&& window
|
|
&& window==tcpd->fwd->window
|
|
&& seq==tcpd->fwd->nextseq
|
|
&& ack==tcpd->fwd->lastack
|
|
&& (tcpd->rev->lastsegmentflags&TCP_A_KEEP_ALIVE)
|
|
&& (flags&(TH_SYN|TH_FIN|TH_RST))==0 ){
|
|
if(!tcpd->ta){
|
|
tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE, tcpd);
|
|
}
|
|
tcpd->ta->flags|=TCP_A_KEEP_ALIVE_ACK;
|
|
goto finished_fwd;
|
|
}
|
|
|
|
|
|
/* ZERO WINDOW PROBE ACK
|
|
* It is a zerowindowprobe ack if it repeats the previous ACK and if
|
|
* the last segment in the reverse direction was a zerowindowprobe
|
|
* It also repeats the previous zero window indication
|
|
*/
|
|
/*QQQ tested*/
|
|
if( seglen==0
|
|
&& window==0
|
|
&& window==tcpd->fwd->window
|
|
&& seq==tcpd->fwd->nextseq
|
|
&& ack==tcpd->fwd->lastack
|
|
&& (tcpd->rev->lastsegmentflags&TCP_A_ZERO_WINDOW_PROBE)
|
|
&& (flags&(TH_SYN|TH_FIN|TH_RST))==0 ){
|
|
if(!tcpd->ta){
|
|
tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE, tcpd);
|
|
}
|
|
tcpd->ta->flags|=TCP_A_ZERO_WINDOW_PROBE_ACK;
|
|
goto finished_fwd;
|
|
}
|
|
|
|
|
|
/* DUPLICATE ACK
|
|
* It is a duplicate ack if window/seq/ack is the same as the previous
|
|
* segment and if the segment length is 0
|
|
*/
|
|
if( seglen==0
|
|
&& window
|
|
&& window==tcpd->fwd->window
|
|
&& seq==tcpd->fwd->nextseq
|
|
&& ack==tcpd->fwd->lastack
|
|
&& (flags&(TH_SYN|TH_FIN|TH_RST))==0 ){
|
|
tcpd->fwd->dupacknum++;
|
|
if(!tcpd->ta){
|
|
tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE, tcpd);
|
|
}
|
|
tcpd->ta->flags|=TCP_A_DUPLICATE_ACK;
|
|
tcpd->ta->dupack_num=tcpd->fwd->dupacknum;
|
|
tcpd->ta->dupack_frame=tcpd->fwd->lastnondupack;
|
|
}
|
|
|
|
|
|
finished_fwd:
|
|
/* If this was NOT a dupack we must reset the dupack counters */
|
|
if( (!tcpd->ta) || !(tcpd->ta->flags&TCP_A_DUPLICATE_ACK) ){
|
|
tcpd->fwd->lastnondupack=pinfo->fd->num;
|
|
tcpd->fwd->dupacknum=0;
|
|
}
|
|
|
|
|
|
/* ACKED LOST PACKET
|
|
* If this segment acks beyond the nextseqnum in the other direction
|
|
* then that means we have missed packets going in the
|
|
* other direction
|
|
*
|
|
* We only check this if we have actually seen some seq numbers
|
|
* in the other direction.
|
|
*/
|
|
if( tcpd->rev->nextseq
|
|
&& GT_SEQ(ack, tcpd->rev->nextseq )
|
|
&& (flags&(TH_ACK))!=0 ){
|
|
/*QQQ tested*/
|
|
if(!tcpd->ta){
|
|
tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE, tcpd);
|
|
}
|
|
tcpd->ta->flags|=TCP_A_ACK_LOST_PACKET;
|
|
/* update nextseq in the other direction so we dont get
|
|
* this indication again.
|
|
*/
|
|
tcpd->rev->nextseq=ack;
|
|
}
|
|
|
|
|
|
/* RETRANSMISSION/FAST RETRANSMISSION/OUT-OF-ORDER
|
|
* If the segments contains data and if it does not advance
|
|
* sequence number it must be either of these three.
|
|
* Only test for this if we know what the seq number should be
|
|
* (tcpd->fwd->nextseq)
|
|
*
|
|
* Note that a simple KeepAlive is not a retransmission
|
|
*/
|
|
if( seglen>0
|
|
&& tcpd->fwd->nextseq
|
|
&& (LT_SEQ(seq, tcpd->fwd->nextseq)) ){
|
|
guint32 t;
|
|
|
|
if(tcpd->ta && (tcpd->ta->flags&TCP_A_KEEP_ALIVE) ){
|
|
goto finished_checking_retransmission_type;
|
|
}
|
|
|
|
/* If there were >=2 duplicate ACKs in the reverse direction
|
|
* (there might be duplicate acks missing from the trace)
|
|
* and if this sequence number matches those ACKs
|
|
* and if the packet occurs within 20ms of the last
|
|
* duplicate ack
|
|
* then this is a fast retransmission
|
|
*/
|
|
t=(pinfo->fd->abs_ts.secs-tcpd->rev->lastacktime.secs)*1000000000;
|
|
t=t+(pinfo->fd->abs_ts.nsecs)-tcpd->rev->lastacktime.nsecs;
|
|
if( tcpd->rev->dupacknum>=2
|
|
&& tcpd->rev->lastack==seq
|
|
&& t<20000000 ){
|
|
if(!tcpd->ta){
|
|
tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE, tcpd);
|
|
}
|
|
tcpd->ta->flags|=TCP_A_FAST_RETRANSMISSION;
|
|
goto finished_checking_retransmission_type;
|
|
}
|
|
|
|
/* If the segment came <3ms since the segment with the highest
|
|
* seen sequence number, then it is an OUT-OF-ORDER segment.
|
|
* (3ms is an arbitrary number)
|
|
*/
|
|
t=(pinfo->fd->abs_ts.secs-tcpd->fwd->nextseqtime.secs)*1000000000;
|
|
t=t+(pinfo->fd->abs_ts.nsecs)-tcpd->fwd->nextseqtime.nsecs;
|
|
if( t<3000000 ){
|
|
if(!tcpd->ta){
|
|
tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE, tcpd);
|
|
}
|
|
tcpd->ta->flags|=TCP_A_OUT_OF_ORDER;
|
|
goto finished_checking_retransmission_type;
|
|
}
|
|
|
|
/* Then it has to be a generic retransmission */
|
|
if(!tcpd->ta){
|
|
tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE, tcpd);
|
|
}
|
|
tcpd->ta->flags|=TCP_A_RETRANSMISSION;
|
|
nstime_delta(&tcpd->ta->rto_ts, &pinfo->fd->abs_ts, &tcpd->fwd->nextseqtime);
|
|
tcpd->ta->rto_frame=tcpd->fwd->nextseqframe;
|
|
}
|
|
finished_checking_retransmission_type:
|
|
|
|
|
|
/* add this new sequence number to the fwd list */
|
|
TCP_UNACKED_NEW(ual);
|
|
ual->next=tcpd->fwd->segments;
|
|
tcpd->fwd->segments=ual;
|
|
ual->frame=pinfo->fd->num;
|
|
ual->seq=seq;
|
|
ual->ts=pinfo->fd->abs_ts;
|
|
|
|
/* next sequence number is seglen bytes away, plus SYN/FIN which counts as one byte */
|
|
ual->nextseq=seq+seglen;
|
|
if( flags&(TH_SYN|TH_FIN) ){
|
|
ual->nextseq+=1;
|
|
}
|
|
|
|
/* Store the highest number seen so far for nextseq so we can detect
|
|
* when we receive segments that arrive with a "hole"
|
|
* If we dont have anything since before, just store what we got.
|
|
* ZeroWindowProbes are special and dont really advance the nextseq
|
|
*/
|
|
if(GT_SEQ(ual->nextseq, tcpd->fwd->nextseq) || !tcpd->fwd->nextseq) {
|
|
if( !tcpd->ta || !(tcpd->ta->flags&TCP_A_ZERO_WINDOW_PROBE) ){
|
|
tcpd->fwd->nextseq=ual->nextseq;
|
|
tcpd->fwd->nextseqframe=pinfo->fd->num;
|
|
tcpd->fwd->nextseqtime.secs=pinfo->fd->abs_ts.secs;
|
|
tcpd->fwd->nextseqtime.nsecs=pinfo->fd->abs_ts.nsecs;
|
|
}
|
|
}
|
|
|
|
|
|
/* remember what the ack/window is so we can track window updates and retransmissions */
|
|
tcpd->fwd->window=window;
|
|
tcpd->fwd->lastack=ack;
|
|
tcpd->fwd->lastacktime.secs=pinfo->fd->abs_ts.secs;
|
|
tcpd->fwd->lastacktime.nsecs=pinfo->fd->abs_ts.nsecs;
|
|
|
|
|
|
/* if there were any flags set for this segment we need to remember them
|
|
* we only remember the flags for the very last segment though.
|
|
*/
|
|
if(tcpd->ta){
|
|
tcpd->fwd->lastsegmentflags=tcpd->ta->flags;
|
|
} else {
|
|
tcpd->fwd->lastsegmentflags=0;
|
|
}
|
|
|
|
|
|
/* remove all segments this ACKs and we dont need to keep around any more
|
|
*/
|
|
ackcount=0;
|
|
/* first we remove all such segments at the head of the list */
|
|
while((ual=tcpd->rev->segments)){
|
|
tcp_unacked_t *tmpual;
|
|
if(GT_SEQ(ual->nextseq,ack)){
|
|
break;
|
|
}
|
|
if(!ackcount){
|
|
/*qqq do the ACKs segment x delta y */
|
|
}
|
|
ackcount++;
|
|
tmpual=tcpd->rev->segments->next;
|
|
TCP_UNACKED_FREE(ual);
|
|
tcpd->rev->segments=tmpual;
|
|
}
|
|
/* now we remove all such segments that are NOT at the head of the list */
|
|
ual=tcpd->rev->segments;
|
|
while(ual && ual->next){
|
|
tcp_unacked_t *tmpual;
|
|
if(GT_SEQ(ual->next->nextseq,ack)){
|
|
ual=ual->next;
|
|
continue;
|
|
}
|
|
if(!ackcount){
|
|
/*qqq do the ACKs segment x delta y */
|
|
}
|
|
ackcount++;
|
|
tmpual=ual->next->next;
|
|
TCP_UNACKED_FREE(ual->next);
|
|
ual->next=tmpual;
|
|
ual=ual->next;
|
|
}
|
|
|
|
#ifdef REMOVED
|
|
tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE, tcpd);
|
|
tcpd->ta->frame_acked=tcpd->rev->segments->frame;
|
|
nstime_delta(&tcpd->ta->ts, &pinfo->fd->abs_ts, &tcpd->rev->segments->ts);
|
|
#endif
|
|
}
|
|
|
|
static void
|
|
tcp_print_sequence_number_analysis(packet_info *pinfo, tvbuff_t *tvb, proto_tree *parent_tree, struct tcp_analysis *tcpd)
|
|
{
|
|
struct tcp_acked *ta;
|
|
proto_item *item;
|
|
proto_tree *tree;
|
|
|
|
if(!tcpd->ta){
|
|
tcp_analyze_get_acked_struct(pinfo->fd->num, FALSE, tcpd);
|
|
}
|
|
ta=tcpd->ta;
|
|
if(!ta){
|
|
return;
|
|
}
|
|
|
|
item=proto_tree_add_text(parent_tree, tvb, 0, 0, "SEQ/ACK analysis");
|
|
PROTO_ITEM_SET_GENERATED(item);
|
|
tree=proto_item_add_subtree(item, ett_tcp_analysis);
|
|
|
|
/* encapsulate all proto_tree_add_xxx in ifs so we only print what
|
|
data we actually have */
|
|
if(ta->frame_acked){
|
|
item = proto_tree_add_uint(tree, hf_tcp_analysis_acks_frame,
|
|
tvb, 0, 0, ta->frame_acked);
|
|
PROTO_ITEM_SET_GENERATED(item);
|
|
|
|
/* only display RTT if we actually have something we are acking */
|
|
if( ta->ts.secs || ta->ts.nsecs ){
|
|
item = proto_tree_add_time(tree, hf_tcp_analysis_ack_rtt,
|
|
tvb, 0, 0, &ta->ts);
|
|
PROTO_ITEM_SET_GENERATED(item);
|
|
}
|
|
}
|
|
|
|
if(ta->flags){
|
|
proto_item *flags_item=NULL;
|
|
proto_tree *flags_tree=NULL;
|
|
|
|
flags_item = proto_tree_add_item(tree, hf_tcp_analysis_flags, tvb, 0, -1, FALSE);
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
flags_tree=proto_item_add_subtree(flags_item, ett_tcp_analysis);
|
|
if( ta->flags&TCP_A_RETRANSMISSION ){
|
|
flags_item=proto_tree_add_none_format(flags_tree, hf_tcp_analysis_retransmission, tvb, 0, 0, "This frame is a (suspected) retransmission");
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
expert_add_info_format(pinfo, flags_item, PI_SEQUENCE, PI_NOTE, "Retransmission (suspected)");
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[TCP Retransmission] ");
|
|
}
|
|
if( ta->rto_ts.secs || ta->rto_ts.nsecs ){
|
|
item = proto_tree_add_time(flags_tree, hf_tcp_analysis_rto,
|
|
tvb, 0, 0, &ta->rto_ts);
|
|
PROTO_ITEM_SET_GENERATED(item);
|
|
item=proto_tree_add_uint(flags_tree, hf_tcp_analysis_rto_frame, tvb, 0, 0, ta->rto_frame);
|
|
PROTO_ITEM_SET_GENERATED(item);
|
|
}
|
|
}
|
|
if( ta->flags&TCP_A_FAST_RETRANSMISSION ){
|
|
flags_item=proto_tree_add_none_format(flags_tree, hf_tcp_analysis_fast_retransmission, tvb, 0, 0, "This frame is a (suspected) fast retransmission");
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
expert_add_info_format(pinfo, flags_item, PI_SEQUENCE, PI_WARN, "Fast retransmission (suspected)");
|
|
flags_item=proto_tree_add_none_format(flags_tree, hf_tcp_analysis_retransmission, tvb, 0, 0, "This frame is a (suspected) retransmission");
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[TCP Fast Retransmission] ");
|
|
}
|
|
}
|
|
if( ta->flags&TCP_A_OUT_OF_ORDER ){
|
|
flags_item=proto_tree_add_none_format(flags_tree, hf_tcp_analysis_out_of_order, tvb, 0, 0, "This frame is a (suspected) out-of-order segment");
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
expert_add_info_format(pinfo, flags_item, PI_SEQUENCE, PI_WARN, "Out-Of-Order segment");
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[TCP Out-Of-Order] ");
|
|
}
|
|
}
|
|
if( ta->flags&TCP_A_LOST_PACKET ){
|
|
flags_item=proto_tree_add_none_format(flags_tree, hf_tcp_analysis_lost_packet, tvb, 0, 0, "A segment before this frame was lost");
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
expert_add_info_format(pinfo, flags_item, PI_SEQUENCE, PI_WARN, "Previous segment lost (common at capture start)");
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[TCP Previous segment lost] ");
|
|
}
|
|
}
|
|
if( ta->flags&TCP_A_ACK_LOST_PACKET ){
|
|
flags_item=proto_tree_add_none_format(flags_tree, hf_tcp_analysis_ack_lost_packet, tvb, 0, 0, "This frame ACKs a segment we have not seen (lost?)");
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
expert_add_info_format(pinfo, flags_item, PI_SEQUENCE, PI_WARN, "ACKed lost segment (common at capture start)");
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[TCP ACKed lost segment] ");
|
|
}
|
|
}
|
|
if( ta->flags&TCP_A_WINDOW_UPDATE ){
|
|
flags_item=proto_tree_add_none_format(flags_tree, hf_tcp_analysis_window_update, tvb, 0, 0, "This is a tcp window update");
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
expert_add_info_format(pinfo, flags_item, PI_SEQUENCE, PI_NOTE, "Window update");
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[TCP Window Update] ");
|
|
}
|
|
}
|
|
if( ta->flags&TCP_A_WINDOW_FULL ){
|
|
flags_item=proto_tree_add_none_format(flags_tree, hf_tcp_analysis_window_full, tvb, 0, 0, "The transmission window is now completely full");
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
expert_add_info_format(pinfo, flags_item, PI_SEQUENCE, PI_NOTE, "Window is full");
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[TCP Window Full] ");
|
|
}
|
|
}
|
|
if( ta->flags&TCP_A_KEEP_ALIVE ){
|
|
flags_item=proto_tree_add_none_format(flags_tree, hf_tcp_analysis_keep_alive, tvb, 0, 0, "This is a TCP keep-alive segment");
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
expert_add_info_format(pinfo, flags_item, PI_SEQUENCE, PI_NOTE, "Keep-Alive");
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[TCP Keep-Alive] ");
|
|
}
|
|
}
|
|
if( ta->flags&TCP_A_KEEP_ALIVE_ACK ){
|
|
flags_item=proto_tree_add_none_format(flags_tree, hf_tcp_analysis_keep_alive_ack, tvb, 0, 0, "This is an ACK to a TCP keep-alive segment");
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
expert_add_info_format(pinfo, flags_item, PI_SEQUENCE, PI_NOTE, "Keep-Alive ACK");
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[TCP Keep-Alive ACK] ");
|
|
}
|
|
}
|
|
if( ta->dupack_num){
|
|
if( ta->flags&TCP_A_DUPLICATE_ACK ){
|
|
flags_item=proto_tree_add_none_format(flags_tree, hf_tcp_analysis_duplicate_ack, tvb, 0, 0, "This is a TCP duplicate ack");
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[TCP Dup ACK %u#%u] ", ta->dupack_frame, ta->dupack_num);
|
|
}
|
|
}
|
|
flags_item=proto_tree_add_uint(tree, hf_tcp_analysis_duplicate_ack_num,
|
|
tvb, 0, 0, ta->dupack_num);
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
flags_item=proto_tree_add_uint(tree, hf_tcp_analysis_duplicate_ack_frame,
|
|
tvb, 0, 0, ta->dupack_frame);
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
expert_add_info_format(pinfo, flags_item, PI_SEQUENCE, PI_NOTE, "Duplicate ACK (#%u)",
|
|
ta->dupack_num);
|
|
}
|
|
if( ta->flags&TCP_A_ZERO_WINDOW_PROBE ){
|
|
flags_item=proto_tree_add_none_format(flags_tree, hf_tcp_analysis_zero_window_probe, tvb, 0, 0, "This is a TCP zero-window-probe");
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
expert_add_info_format(pinfo, flags_item, PI_SEQUENCE, PI_NOTE, "Zero window probe");
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[TCP ZeroWindowProbe] ");
|
|
}
|
|
}
|
|
if( ta->flags&TCP_A_ZERO_WINDOW ){
|
|
flags_item=proto_tree_add_none_format(flags_tree, hf_tcp_analysis_zero_window, tvb, 0, 0, "This is a ZeroWindow segment");
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
expert_add_info_format(pinfo, flags_item, PI_SEQUENCE, PI_NOTE, "Zero window");
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[TCP ZeroWindow] ");
|
|
}
|
|
}
|
|
if( ta->flags&TCP_A_ZERO_WINDOW_PROBE_ACK ){
|
|
flags_item=proto_tree_add_none_format(flags_tree, hf_tcp_analysis_zero_window_probe_ack, tvb, 0, 0, "This is an ACK to a TCP zero-window-probe");
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
expert_add_info_format(pinfo, flags_item, PI_SEQUENCE, PI_NOTE, "Zero window probe ACK");
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[TCP ZeroWindowProbeAck] ");
|
|
}
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
|
|
/* **************************************************************************
|
|
* End of tcp sequence number analysis
|
|
* **************************************************************************/
|
|
|
|
|
|
|
|
|
|
/* Minimum TCP header length. */
|
|
#define TCPH_MIN_LEN 20
|
|
|
|
/*
|
|
* TCP option
|
|
*/
|
|
|
|
#define TCPOPT_NOP 1 /* Padding */
|
|
#define TCPOPT_EOL 0 /* End of options */
|
|
#define TCPOPT_MSS 2 /* Segment size negotiating */
|
|
#define TCPOPT_WINDOW 3 /* Window scaling */
|
|
#define TCPOPT_SACK_PERM 4 /* SACK Permitted */
|
|
#define TCPOPT_SACK 5 /* SACK Block */
|
|
#define TCPOPT_ECHO 6
|
|
#define TCPOPT_ECHOREPLY 7
|
|
#define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
|
|
#define TCPOPT_CC 11
|
|
#define TCPOPT_CCNEW 12
|
|
#define TCPOPT_CCECHO 13
|
|
#define TCPOPT_MD5 19 /* RFC2385 */
|
|
|
|
/*
|
|
* TCP option lengths
|
|
*/
|
|
|
|
#define TCPOLEN_MSS 4
|
|
#define TCPOLEN_WINDOW 3
|
|
#define TCPOLEN_SACK_PERM 2
|
|
#define TCPOLEN_SACK_MIN 2
|
|
#define TCPOLEN_ECHO 6
|
|
#define TCPOLEN_ECHOREPLY 6
|
|
#define TCPOLEN_TIMESTAMP 10
|
|
#define TCPOLEN_CC 6
|
|
#define TCPOLEN_CCNEW 6
|
|
#define TCPOLEN_CCECHO 6
|
|
#define TCPOLEN_MD5 18
|
|
|
|
|
|
|
|
/* Desegmentation of TCP streams */
|
|
/* table to hold defragmented TCP streams */
|
|
static GHashTable *tcp_fragment_table = NULL;
|
|
static void
|
|
tcp_fragment_init(void)
|
|
{
|
|
fragment_table_init(&tcp_fragment_table);
|
|
}
|
|
|
|
/* functions to trace tcp segments */
|
|
/* Enable desegmenting of TCP streams */
|
|
static gboolean tcp_desegment = TRUE;
|
|
|
|
static void
|
|
desegment_tcp(tvbuff_t *tvb, packet_info *pinfo, int offset,
|
|
guint32 seq, guint32 nxtseq,
|
|
guint32 sport, guint32 dport,
|
|
proto_tree *tree, proto_tree *tcp_tree,
|
|
struct tcp_analysis *tcpd)
|
|
{
|
|
struct tcpinfo *tcpinfo = pinfo->private_data;
|
|
fragment_data *ipfd_head;
|
|
gboolean must_desegment;
|
|
gboolean called_dissector;
|
|
int another_pdu_follows;
|
|
int deseg_offset;
|
|
guint32 deseg_seq;
|
|
gint nbytes;
|
|
proto_item *item;
|
|
proto_item *frag_tree_item;
|
|
proto_item *tcp_tree_item;
|
|
struct tcp_multisegment_pdu *msp;
|
|
|
|
again:
|
|
ipfd_head=NULL;
|
|
must_desegment = FALSE;
|
|
called_dissector = FALSE;
|
|
another_pdu_follows = 0;
|
|
msp=NULL;
|
|
|
|
/*
|
|
* Initialize these to assume no desegmentation.
|
|
* If that's not the case, these will be set appropriately
|
|
* by the subdissector.
|
|
*/
|
|
pinfo->desegment_offset = 0;
|
|
pinfo->desegment_len = 0;
|
|
|
|
/*
|
|
* Initialize this to assume that this segment will just be
|
|
* added to the middle of a desegmented chunk of data, so
|
|
* that we should show it all as data.
|
|
* If that's not the case, it will be set appropriately.
|
|
*/
|
|
deseg_offset = offset;
|
|
|
|
/* find the most previous PDU starting before this sequence number */
|
|
msp=se_tree_lookup32_le(tcpd->fwd->multisegment_pdus, seq-1);
|
|
if(msp && msp->seq<=seq && msp->nxtpdu>seq){
|
|
int len;
|
|
|
|
if(!pinfo->fd->flags.visited){
|
|
msp->last_frame=pinfo->fd->num;
|
|
msp->last_frame_time=pinfo->fd->abs_ts;
|
|
}
|
|
|
|
/* OK, this PDU was found, which means the segment continues
|
|
a higher-level PDU and that we must desegment it.
|
|
*/
|
|
len=MIN(nxtseq, msp->nxtpdu) - seq;
|
|
ipfd_head = fragment_add(tvb, offset, pinfo, msp->first_frame,
|
|
tcp_fragment_table,
|
|
seq - msp->seq,
|
|
len,
|
|
(LT_SEQ (nxtseq,msp->nxtpdu)) );
|
|
/* if we didnt consume the entire segment there is another pdu
|
|
* starting beyong the end of this one
|
|
*/
|
|
if(msp->nxtpdu<nxtseq && len>0){
|
|
another_pdu_follows=len;
|
|
}
|
|
} else {
|
|
/* This segment was not found in our table, so it doesn't
|
|
contain a continuation of a higher-level PDU.
|
|
Call the normal subdissector.
|
|
*/
|
|
process_tcp_payload(tvb, offset, pinfo, tree, tcp_tree,
|
|
sport, dport, 0, 0, FALSE, tcpd);
|
|
called_dissector = TRUE;
|
|
|
|
/* Did the subdissector ask us to desegment some more data
|
|
before it could handle the packet?
|
|
If so we have to create some structures in our table but
|
|
this is something we only do the first time we see this
|
|
packet.
|
|
*/
|
|
if(pinfo->desegment_len) {
|
|
if (!pinfo->fd->flags.visited)
|
|
must_desegment = TRUE;
|
|
|
|
/*
|
|
* Set "deseg_offset" to the offset in "tvb"
|
|
* of the first byte of data that the
|
|
* subdissector didn't process.
|
|
*/
|
|
deseg_offset = offset + pinfo->desegment_offset;
|
|
}
|
|
|
|
/* Either no desegmentation is necessary, or this is
|
|
segment contains the beginning but not the end of
|
|
a higher-level PDU and thus isn't completely
|
|
desegmented.
|
|
*/
|
|
ipfd_head = NULL;
|
|
}
|
|
|
|
|
|
/* is it completely desegmented? */
|
|
if(ipfd_head){
|
|
/*
|
|
* Yes, we think it is.
|
|
* We only call subdissector for the last segment.
|
|
* Note that the last segment may include more than what
|
|
* we needed.
|
|
*/
|
|
if(ipfd_head->reassembled_in==pinfo->fd->num){
|
|
/*
|
|
* OK, this is the last segment.
|
|
* Let's call the subdissector with the desegmented
|
|
* data.
|
|
*/
|
|
tvbuff_t *next_tvb;
|
|
int old_len;
|
|
|
|
/* create a new TVB structure for desegmented data */
|
|
next_tvb = tvb_new_real_data(ipfd_head->data,
|
|
ipfd_head->datalen, ipfd_head->datalen);
|
|
|
|
/* add this tvb as a child to the original one */
|
|
tvb_set_child_real_data_tvbuff(tvb, next_tvb);
|
|
|
|
/* add desegmented data to the data source list */
|
|
add_new_data_source(pinfo, next_tvb, "Reassembled TCP");
|
|
|
|
/*
|
|
* Supply the sequence number of the first of the
|
|
* reassembled bytes.
|
|
*/
|
|
tcpinfo->seq = msp->seq;
|
|
|
|
/* indicate that this is reassembled data */
|
|
tcpinfo->is_reassembled = TRUE;
|
|
|
|
/* call subdissector */
|
|
process_tcp_payload(next_tvb, 0, pinfo, tree,
|
|
tcp_tree, sport, dport, 0, 0, FALSE, tcpd);
|
|
called_dissector = TRUE;
|
|
|
|
/*
|
|
* OK, did the subdissector think it was completely
|
|
* desegmented, or does it think we need even more
|
|
* data?
|
|
*/
|
|
old_len=(int)(tvb_reported_length(next_tvb)-tvb_reported_length_remaining(tvb, offset));
|
|
if(pinfo->desegment_len &&
|
|
pinfo->desegment_offset<=old_len){
|
|
/*
|
|
* "desegment_len" isn't 0, so it needs more
|
|
* data for something - and "desegment_offset"
|
|
* is before "old_len", so it needs more data
|
|
* to dissect the stuff we thought was
|
|
* completely desegmented (as opposed to the
|
|
* stuff at the beginning being completely
|
|
* desegmented, but the stuff at the end
|
|
* being a new higher-level PDU that also
|
|
* needs desegmentation).
|
|
*/
|
|
fragment_set_partial_reassembly(pinfo,msp->first_frame,tcp_fragment_table);
|
|
msp->nxtpdu=msp->seq+tvb_reported_length(next_tvb) + pinfo->desegment_len;
|
|
} else {
|
|
/*
|
|
* Show the stuff in this TCP segment as
|
|
* just raw TCP segment data.
|
|
*/
|
|
nbytes =
|
|
tvb_reported_length_remaining(tvb, offset);
|
|
proto_tree_add_text(tcp_tree, tvb, offset, -1,
|
|
"TCP segment data (%u byte%s)", nbytes,
|
|
plurality(nbytes, "", "s"));
|
|
|
|
/*
|
|
* The subdissector thought it was completely
|
|
* desegmented (although the stuff at the
|
|
* end may, in turn, require desegmentation),
|
|
* so we show a tree with all segments.
|
|
*/
|
|
show_fragment_tree(ipfd_head, &tcp_segment_items,
|
|
tree, pinfo, next_tvb, &frag_tree_item);
|
|
/*
|
|
* The toplevel fragment subtree is now
|
|
* behind all desegmented data; move it
|
|
* right behind the TCP tree.
|
|
*/
|
|
tcp_tree_item = proto_tree_get_parent(tcp_tree);
|
|
if(frag_tree_item && tcp_tree_item) {
|
|
proto_tree_move_item(tree, tcp_tree_item, frag_tree_item);
|
|
}
|
|
|
|
/* Did the subdissector ask us to desegment
|
|
some more data? This means that the data
|
|
at the beginning of this segment completed
|
|
a higher-level PDU, but the data at the
|
|
end of this segment started a higher-level
|
|
PDU but didn't complete it.
|
|
|
|
If so, we have to create some structures
|
|
in our table, but this is something we
|
|
only do the first time we see this packet.
|
|
*/
|
|
if(pinfo->desegment_len) {
|
|
if (!pinfo->fd->flags.visited)
|
|
must_desegment = TRUE;
|
|
|
|
/* The stuff we couldn't dissect
|
|
must have come from this segment,
|
|
so it's all in "tvb".
|
|
|
|
"pinfo->desegment_offset" is
|
|
relative to the beginning of
|
|
"next_tvb"; we want an offset
|
|
relative to the beginning of "tvb".
|
|
|
|
First, compute the offset relative
|
|
to the *end* of "next_tvb" - i.e.,
|
|
the number of bytes before the end
|
|
of "next_tvb" at which the
|
|
subdissector stopped. That's the
|
|
length of "next_tvb" minus the
|
|
offset, relative to the beginning
|
|
of "next_tvb, at which the
|
|
subdissector stopped.
|
|
*/
|
|
deseg_offset =
|
|
ipfd_head->datalen - pinfo->desegment_offset;
|
|
|
|
/* "tvb" and "next_tvb" end at the
|
|
same byte of data, so the offset
|
|
relative to the end of "next_tvb"
|
|
of the byte at which we stopped
|
|
is also the offset relative to
|
|
the end of "tvb" of the byte at
|
|
which we stopped.
|
|
|
|
Convert that back into an offset
|
|
relative to the beginninng of
|
|
"tvb", by taking the length of
|
|
"tvb" and subtracting the offset
|
|
relative to the end.
|
|
*/
|
|
deseg_offset=tvb_reported_length(tvb) - deseg_offset;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (must_desegment) {
|
|
/* If the dissector requested "reassemble until FIN"
|
|
* just set this flag for the flow and let reassembly
|
|
* proceed at normal. We will check/pick up these
|
|
* reassembled PDUs later down in dissect_tcp() when checking
|
|
* for the FIN flag.
|
|
*/
|
|
if(pinfo->desegment_len==DESEGMENT_UNTIL_FIN){
|
|
tcpd->fwd->flags|=TCP_FLOW_REASSEMBLE_UNTIL_FIN;
|
|
}
|
|
|
|
/*
|
|
* The sequence number at which the stuff to be desegmented
|
|
* starts is the sequence number of the byte at an offset
|
|
* of "deseg_offset" into "tvb".
|
|
*
|
|
* The sequence number of the byte at an offset of "offset"
|
|
* is "seq", i.e. the starting sequence number of this
|
|
* segment, so the sequence number of the byte at
|
|
* "deseg_offset" is "seq + (deseg_offset - offset)".
|
|
*/
|
|
deseg_seq = seq + (deseg_offset - offset);
|
|
|
|
if( ((nxtseq - deseg_seq) <= 1024*1024)
|
|
&& (!pinfo->fd->flags.visited) ){
|
|
msp = pdu_store_sequencenumber_of_next_pdu(pinfo, deseg_seq,
|
|
nxtseq + pinfo->desegment_len, tcpd);
|
|
|
|
/* add this segment as the first one for this new pdu */
|
|
fragment_add(tvb, deseg_offset, pinfo, msp->first_frame,
|
|
tcp_fragment_table,
|
|
0,
|
|
nxtseq - deseg_seq,
|
|
LT_SEQ(nxtseq, msp->nxtpdu));
|
|
}
|
|
}
|
|
|
|
if (!called_dissector || pinfo->desegment_len != 0) {
|
|
if (ipfd_head != NULL && ipfd_head->reassembled_in != 0 &&
|
|
!(ipfd_head->flags & FD_PARTIAL_REASSEMBLY)) {
|
|
/*
|
|
* We know what frame this PDU is reassembled in;
|
|
* let the user know.
|
|
*/
|
|
item=proto_tree_add_uint(tcp_tree, hf_tcp_reassembled_in,
|
|
tvb, 0, 0, ipfd_head->reassembled_in);
|
|
PROTO_ITEM_SET_GENERATED(item);
|
|
}
|
|
|
|
/*
|
|
* Either we didn't call the subdissector at all (i.e.,
|
|
* this is a segment that contains the middle of a
|
|
* higher-level PDU, but contains neither the beginning
|
|
* nor the end), or the subdissector couldn't dissect it
|
|
* all, as some data was missing (i.e., it set
|
|
* "pinfo->desegment_len" to the amount of additional
|
|
* data it needs).
|
|
*/
|
|
if (pinfo->desegment_offset == 0) {
|
|
/*
|
|
* It couldn't, in fact, dissect any of it (the
|
|
* first byte it couldn't dissect is at an offset
|
|
* of "pinfo->desegment_offset" from the beginning
|
|
* of the payload, and that's 0).
|
|
* Just mark this as TCP.
|
|
*/
|
|
if (check_col(pinfo->cinfo, COL_PROTOCOL)){
|
|
col_set_str(pinfo->cinfo, COL_PROTOCOL, "TCP");
|
|
}
|
|
if (check_col(pinfo->cinfo, COL_INFO)){
|
|
col_set_str(pinfo->cinfo, COL_INFO, "[TCP segment of a reassembled PDU]");
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Show what's left in the packet as just raw TCP segment
|
|
* data.
|
|
* XXX - remember what protocol the last subdissector
|
|
* was, and report it as a continuation of that, instead?
|
|
*/
|
|
nbytes = tvb_reported_length_remaining(tvb, deseg_offset);
|
|
proto_tree_add_text(tcp_tree, tvb, deseg_offset, -1,
|
|
"TCP segment data (%u byte%s)", nbytes,
|
|
plurality(nbytes, "", "s"));
|
|
}
|
|
pinfo->can_desegment=0;
|
|
pinfo->desegment_offset = 0;
|
|
pinfo->desegment_len = 0;
|
|
|
|
if(another_pdu_follows){
|
|
/* there was another pdu following this one. */
|
|
pinfo->can_desegment=2;
|
|
/* we also have to prevent the dissector from changing the
|
|
* PROTOCOL and INFO colums since what follows may be an
|
|
* incomplete PDU and we dont want it be changed back from
|
|
* <Protocol> to <TCP>
|
|
* XXX There is no good way to block the PROTOCOL column
|
|
* from being changed yet so we set the entire row unwritable.
|
|
*/
|
|
col_set_fence(pinfo->cinfo, COL_INFO);
|
|
col_set_writable(pinfo->cinfo, FALSE);
|
|
offset += another_pdu_follows;
|
|
seq += another_pdu_follows;
|
|
goto again;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Loop for dissecting PDUs within a TCP stream; assumes that a PDU
|
|
* consists of a fixed-length chunk of data that contains enough information
|
|
* to determine the length of the PDU, followed by rest of the PDU.
|
|
*
|
|
* The first three arguments are the arguments passed to the dissector
|
|
* that calls this routine.
|
|
*
|
|
* "proto_desegment" is the dissector's flag controlling whether it should
|
|
* desegment PDUs that cross TCP segment boundaries.
|
|
*
|
|
* "fixed_len" is the length of the fixed-length part of the PDU.
|
|
*
|
|
* "get_pdu_len()" is a routine called to get the length of the PDU from
|
|
* the fixed-length part of the PDU; it's passed "tvb" and "offset".
|
|
*
|
|
* "dissect_pdu()" is the routine to dissect a PDU.
|
|
*/
|
|
void
|
|
tcp_dissect_pdus(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
|
|
gboolean proto_desegment, guint fixed_len,
|
|
guint (*get_pdu_len)(tvbuff_t *, int),
|
|
dissector_t dissect_pdu)
|
|
{
|
|
volatile int offset = 0;
|
|
int offset_before;
|
|
guint length_remaining;
|
|
guint plen;
|
|
guint length;
|
|
tvbuff_t *next_tvb;
|
|
|
|
while (tvb_reported_length_remaining(tvb, offset) != 0) {
|
|
/*
|
|
* We use "tvb_ensure_length_remaining()" to make sure there actually
|
|
* *is* data remaining. The protocol we're handling could conceivably
|
|
* consists of a sequence of fixed-length PDUs, and therefore the
|
|
* "get_pdu_len" routine might not actually fetch anything from
|
|
* the tvbuff, and thus might not cause an exception to be thrown if
|
|
* we've run past the end of the tvbuff.
|
|
*
|
|
* This means we're guaranteed that "length_remaining" is positive.
|
|
*/
|
|
length_remaining = tvb_ensure_length_remaining(tvb, offset);
|
|
|
|
/*
|
|
* Can we do reassembly?
|
|
*/
|
|
if (proto_desegment && pinfo->can_desegment) {
|
|
/*
|
|
* Yes - is the fixed-length part of the PDU split across segment
|
|
* boundaries?
|
|
*/
|
|
if (length_remaining < fixed_len) {
|
|
/*
|
|
* Yes. Tell the TCP dissector where the data for this message
|
|
* starts in the data it handed us, and how many more bytes we
|
|
* need, and return.
|
|
*/
|
|
pinfo->desegment_offset = offset;
|
|
pinfo->desegment_len = fixed_len - length_remaining;
|
|
return;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Get the length of the PDU.
|
|
*/
|
|
plen = (*get_pdu_len)(tvb, offset);
|
|
if (plen < fixed_len) {
|
|
/*
|
|
* The PDU length from the fixed-length portion probably didn't
|
|
* include the fixed-length portion's length, and was probably so
|
|
* large that the total length overflowed.
|
|
*
|
|
* Report this as an error.
|
|
*/
|
|
show_reported_bounds_error(tvb, pinfo, tree);
|
|
return;
|
|
}
|
|
|
|
/* give a hint to TCP where the next PDU starts
|
|
* so that it can attempt to find it in case it starts
|
|
* somewhere in the middle of a segment.
|
|
*/
|
|
if(!pinfo->fd->flags.visited && tcp_analyze_seq){
|
|
guint remaining_bytes;
|
|
remaining_bytes=tvb_reported_length_remaining(tvb, offset);
|
|
if(plen>remaining_bytes){
|
|
pinfo->want_pdu_tracking=2;
|
|
pinfo->bytes_until_next_pdu=plen-remaining_bytes;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Can we do reassembly?
|
|
*/
|
|
if (proto_desegment && pinfo->can_desegment) {
|
|
/*
|
|
* Yes - is the PDU split across segment boundaries?
|
|
*/
|
|
if (length_remaining < plen) {
|
|
/*
|
|
* Yes. Tell the TCP dissector where the data for this message
|
|
* starts in the data it handed us, and how many more bytes we
|
|
* need, and return.
|
|
*/
|
|
pinfo->desegment_offset = offset;
|
|
pinfo->desegment_len = plen - length_remaining;
|
|
return;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Construct a tvbuff containing the amount of the payload we have
|
|
* available. Make its reported length the amount of data in the PDU.
|
|
*
|
|
* XXX - if reassembly isn't enabled. the subdissector will throw a
|
|
* BoundsError exception, rather than a ReportedBoundsError exception.
|
|
* We really want a tvbuff where the length is "length", the reported
|
|
* length is "plen", and the "if the snapshot length were infinite"
|
|
* length is the minimum of the reported length of the tvbuff handed
|
|
* to us and "plen", with a new type of exception thrown if the offset
|
|
* is within the reported length but beyond that third length, with
|
|
* that exception getting the "Unreassembled Packet" error.
|
|
*/
|
|
length = length_remaining;
|
|
if (length > plen)
|
|
length = plen;
|
|
next_tvb = tvb_new_subset(tvb, offset, length, plen);
|
|
|
|
/*
|
|
* Dissect the PDU.
|
|
*
|
|
* Catch the ReportedBoundsError exception; if this particular message
|
|
* happens to get a ReportedBoundsError exception, that doesn't mean
|
|
* that we should stop dissecting PDUs within this frame or chunk of
|
|
* reassembled data.
|
|
*
|
|
* If it gets a BoundsError, we can stop, as there's nothing more to
|
|
* see, so we just re-throw it.
|
|
*/
|
|
TRY {
|
|
(*dissect_pdu)(next_tvb, pinfo, tree);
|
|
}
|
|
CATCH(BoundsError) {
|
|
RETHROW;
|
|
}
|
|
CATCH(ReportedBoundsError) {
|
|
show_reported_bounds_error(tvb, pinfo, tree);
|
|
}
|
|
ENDTRY;
|
|
|
|
/*
|
|
* Step to the next PDU.
|
|
* Make sure we don't overflow.
|
|
*/
|
|
offset_before = offset;
|
|
offset += plen;
|
|
if (offset <= offset_before)
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void
|
|
tcp_info_append_uint(packet_info *pinfo, const char *abbrev, guint32 val)
|
|
{
|
|
if (check_col(pinfo->cinfo, COL_INFO))
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, " %s=%u", abbrev, val);
|
|
}
|
|
|
|
static void
|
|
dissect_tcpopt_maxseg(const ip_tcp_opt *optp, tvbuff_t *tvb,
|
|
int offset, guint optlen, packet_info *pinfo, proto_tree *opt_tree)
|
|
{
|
|
guint16 mss;
|
|
|
|
mss = tvb_get_ntohs(tvb, offset + 2);
|
|
proto_tree_add_boolean_hidden(opt_tree, hf_tcp_option_mss, tvb, offset,
|
|
optlen, TRUE);
|
|
proto_tree_add_uint_format(opt_tree, hf_tcp_option_mss_val, tvb, offset,
|
|
optlen, mss, "%s: %u bytes", optp->name, mss);
|
|
tcp_info_append_uint(pinfo, "MSS", mss);
|
|
}
|
|
|
|
static void
|
|
dissect_tcpopt_wscale(const ip_tcp_opt *optp, tvbuff_t *tvb,
|
|
int offset, guint optlen, packet_info *pinfo, proto_tree *opt_tree)
|
|
{
|
|
guint8 ws;
|
|
struct tcp_analysis *tcpd=NULL;
|
|
|
|
tcpd=get_tcp_conversation_data(pinfo);
|
|
|
|
ws = tvb_get_guint8(tvb, offset + 2);
|
|
proto_tree_add_boolean_hidden(opt_tree, hf_tcp_option_wscale, tvb,
|
|
offset, optlen, TRUE);
|
|
proto_tree_add_uint_format(opt_tree, hf_tcp_option_wscale_val, tvb,
|
|
offset, optlen, ws, "%s: %u (multiply by %u)",
|
|
optp->name, ws, 1 << ws);
|
|
tcp_info_append_uint(pinfo, "WS", ws);
|
|
if(!pinfo->fd->flags.visited && tcp_analyze_seq && tcp_relative_seq){
|
|
pdu_store_window_scale_option(ws, tcpd);
|
|
}
|
|
}
|
|
|
|
static void
|
|
dissect_tcpopt_sack(const ip_tcp_opt *optp, tvbuff_t *tvb,
|
|
int offset, guint optlen, packet_info *pinfo, proto_tree *opt_tree)
|
|
{
|
|
proto_tree *field_tree = NULL;
|
|
proto_item *tf=NULL;
|
|
guint32 leftedge, rightedge;
|
|
struct tcp_analysis *tcpd=NULL;
|
|
guint32 base_ack=0;
|
|
|
|
if(tcp_analyze_seq && tcp_relative_seq){
|
|
/* find(or create if needed) the conversation for this tcp session */
|
|
tcpd=get_tcp_conversation_data(pinfo);
|
|
|
|
base_ack=tcpd->rev->base_seq;
|
|
}
|
|
|
|
tf = proto_tree_add_text(opt_tree, tvb, offset, optlen, "%s:", optp->name);
|
|
offset += 2; /* skip past type and length */
|
|
optlen -= 2; /* subtract size of type and length */
|
|
while (optlen > 0) {
|
|
if (field_tree == NULL) {
|
|
/* Haven't yet made a subtree out of this option. Do so. */
|
|
field_tree = proto_item_add_subtree(tf, *optp->subtree_index);
|
|
proto_tree_add_boolean_hidden(field_tree, hf_tcp_option_sack, tvb,
|
|
offset, optlen, TRUE);
|
|
}
|
|
if (optlen < 4) {
|
|
proto_tree_add_text(field_tree, tvb, offset, optlen,
|
|
"(suboption would go past end of option)");
|
|
break;
|
|
}
|
|
leftedge = tvb_get_ntohl(tvb, offset)-base_ack;
|
|
proto_tree_add_uint_format(field_tree, hf_tcp_option_sack_sle, tvb,
|
|
offset, 4, leftedge,
|
|
"left edge = %u%s", leftedge,
|
|
tcp_relative_seq ? " (relative)" : "");
|
|
|
|
optlen -= 4;
|
|
if (optlen < 4) {
|
|
proto_tree_add_text(field_tree, tvb, offset, optlen,
|
|
"(suboption would go past end of option)");
|
|
break;
|
|
}
|
|
/* XXX - check whether it goes past end of packet */
|
|
rightedge = tvb_get_ntohl(tvb, offset + 4)-base_ack;
|
|
optlen -= 4;
|
|
proto_tree_add_uint_format(field_tree, hf_tcp_option_sack_sre, tvb,
|
|
offset+4, 4, rightedge,
|
|
"right edge = %u%s", rightedge,
|
|
tcp_relative_seq ? " (relative)" : "");
|
|
tcp_info_append_uint(pinfo, "SLE", leftedge);
|
|
tcp_info_append_uint(pinfo, "SRE", rightedge);
|
|
proto_item_append_text(field_tree, " %u-%u", leftedge, rightedge);
|
|
offset += 8;
|
|
}
|
|
}
|
|
|
|
static void
|
|
dissect_tcpopt_echo(const ip_tcp_opt *optp, tvbuff_t *tvb,
|
|
int offset, guint optlen, packet_info *pinfo, proto_tree *opt_tree)
|
|
{
|
|
guint32 echo;
|
|
|
|
echo = tvb_get_ntohl(tvb, offset + 2);
|
|
proto_tree_add_boolean_hidden(opt_tree, hf_tcp_option_echo, tvb, offset,
|
|
optlen, TRUE);
|
|
proto_tree_add_text(opt_tree, tvb, offset, optlen,
|
|
"%s: %u", optp->name, echo);
|
|
tcp_info_append_uint(pinfo, "ECHO", echo);
|
|
}
|
|
|
|
static void
|
|
dissect_tcpopt_timestamp(const ip_tcp_opt *optp, tvbuff_t *tvb,
|
|
int offset, guint optlen, packet_info *pinfo, proto_tree *opt_tree)
|
|
{
|
|
guint32 tsv, tser;
|
|
|
|
tsv = tvb_get_ntohl(tvb, offset + 2);
|
|
tser = tvb_get_ntohl(tvb, offset + 6);
|
|
proto_tree_add_boolean_hidden(opt_tree, hf_tcp_option_time_stamp, tvb,
|
|
offset, optlen, TRUE);
|
|
proto_tree_add_text(opt_tree, tvb, offset, optlen,
|
|
"%s: tsval %u, tsecr %u", optp->name, tsv, tser);
|
|
tcp_info_append_uint(pinfo, "TSV", tsv);
|
|
tcp_info_append_uint(pinfo, "TSER", tser);
|
|
}
|
|
|
|
static void
|
|
dissect_tcpopt_cc(const ip_tcp_opt *optp, tvbuff_t *tvb,
|
|
int offset, guint optlen, packet_info *pinfo, proto_tree *opt_tree)
|
|
{
|
|
guint32 cc;
|
|
|
|
cc = tvb_get_ntohl(tvb, offset + 2);
|
|
proto_tree_add_boolean_hidden(opt_tree, hf_tcp_option_cc, tvb, offset,
|
|
optlen, TRUE);
|
|
proto_tree_add_text(opt_tree, tvb, offset, optlen,
|
|
"%s: %u", optp->name, cc);
|
|
tcp_info_append_uint(pinfo, "CC", cc);
|
|
}
|
|
|
|
static const ip_tcp_opt tcpopts[] = {
|
|
{
|
|
TCPOPT_EOL,
|
|
"EOL",
|
|
NULL,
|
|
NO_LENGTH,
|
|
0,
|
|
NULL,
|
|
},
|
|
{
|
|
TCPOPT_NOP,
|
|
"NOP",
|
|
NULL,
|
|
NO_LENGTH,
|
|
0,
|
|
NULL,
|
|
},
|
|
{
|
|
TCPOPT_MSS,
|
|
"Maximum segment size",
|
|
NULL,
|
|
FIXED_LENGTH,
|
|
TCPOLEN_MSS,
|
|
dissect_tcpopt_maxseg
|
|
},
|
|
{
|
|
TCPOPT_WINDOW,
|
|
"Window scale",
|
|
NULL,
|
|
FIXED_LENGTH,
|
|
TCPOLEN_WINDOW,
|
|
dissect_tcpopt_wscale
|
|
},
|
|
{
|
|
TCPOPT_SACK_PERM,
|
|
"SACK permitted",
|
|
NULL,
|
|
FIXED_LENGTH,
|
|
TCPOLEN_SACK_PERM,
|
|
NULL,
|
|
},
|
|
{
|
|
TCPOPT_SACK,
|
|
"SACK",
|
|
&ett_tcp_option_sack,
|
|
VARIABLE_LENGTH,
|
|
TCPOLEN_SACK_MIN,
|
|
dissect_tcpopt_sack
|
|
},
|
|
{
|
|
TCPOPT_ECHO,
|
|
"Echo",
|
|
NULL,
|
|
FIXED_LENGTH,
|
|
TCPOLEN_ECHO,
|
|
dissect_tcpopt_echo
|
|
},
|
|
{
|
|
TCPOPT_ECHOREPLY,
|
|
"Echo reply",
|
|
NULL,
|
|
FIXED_LENGTH,
|
|
TCPOLEN_ECHOREPLY,
|
|
dissect_tcpopt_echo
|
|
},
|
|
{
|
|
TCPOPT_TIMESTAMP,
|
|
"Time stamp",
|
|
NULL,
|
|
FIXED_LENGTH,
|
|
TCPOLEN_TIMESTAMP,
|
|
dissect_tcpopt_timestamp
|
|
},
|
|
{
|
|
TCPOPT_CC,
|
|
"CC",
|
|
NULL,
|
|
FIXED_LENGTH,
|
|
TCPOLEN_CC,
|
|
dissect_tcpopt_cc
|
|
},
|
|
{
|
|
TCPOPT_CCNEW,
|
|
"CC.NEW",
|
|
NULL,
|
|
FIXED_LENGTH,
|
|
TCPOLEN_CCNEW,
|
|
dissect_tcpopt_cc
|
|
},
|
|
{
|
|
TCPOPT_CCECHO,
|
|
"CC.ECHO",
|
|
NULL,
|
|
FIXED_LENGTH,
|
|
TCPOLEN_CCECHO,
|
|
dissect_tcpopt_cc
|
|
},
|
|
{
|
|
TCPOPT_MD5,
|
|
"TCP MD5 signature",
|
|
NULL,
|
|
FIXED_LENGTH,
|
|
TCPOLEN_MD5,
|
|
NULL
|
|
}
|
|
};
|
|
|
|
#define N_TCP_OPTS (sizeof tcpopts / sizeof tcpopts[0])
|
|
|
|
/* Determine if there is a sub-dissector and call it; return TRUE
|
|
if there was a sub-dissector, FALSE otherwise.
|
|
|
|
This has been separated into a stand alone routine to other protocol
|
|
dissectors can call to it, e.g., SOCKS. */
|
|
|
|
static gboolean try_heuristic_first = FALSE;
|
|
|
|
|
|
/* this function can be called with tcpd==NULL as from the msproxy dissector */
|
|
gboolean
|
|
decode_tcp_ports(tvbuff_t *tvb, int offset, packet_info *pinfo,
|
|
proto_tree *tree, int src_port, int dst_port,
|
|
struct tcp_analysis *tcpd)
|
|
{
|
|
tvbuff_t *next_tvb;
|
|
int low_port, high_port;
|
|
int save_desegment_offset;
|
|
guint32 save_desegment_len;
|
|
|
|
/* dont call subdissectors for keepalive or zerowindowprobes
|
|
* even though they do contain payload "data"
|
|
* keeaplives just contain garbage and zwp contain too little data (1 byte)
|
|
* so why bother.
|
|
*/
|
|
if(tcpd && tcpd->ta){
|
|
if(tcpd->ta->flags&(TCP_A_ZERO_WINDOW_PROBE|TCP_A_KEEP_ALIVE)){
|
|
return TRUE;
|
|
}
|
|
}
|
|
|
|
next_tvb = tvb_new_subset(tvb, offset, -1, -1);
|
|
|
|
/* determine if this packet is part of a conversation and call dissector */
|
|
/* for the conversation if available */
|
|
|
|
if (try_conversation_dissector(&pinfo->src, &pinfo->dst, PT_TCP,
|
|
src_port, dst_port, next_tvb, pinfo, tree)){
|
|
pinfo->want_pdu_tracking -= !!(pinfo->want_pdu_tracking);
|
|
return TRUE;
|
|
}
|
|
|
|
if (try_heuristic_first) {
|
|
/* do lookup with the heuristic subdissector table */
|
|
save_desegment_offset = pinfo->desegment_offset;
|
|
save_desegment_len = pinfo->desegment_len;
|
|
if (dissector_try_heuristic(heur_subdissector_list, next_tvb, pinfo, tree)){
|
|
pinfo->want_pdu_tracking -= !!(pinfo->want_pdu_tracking);
|
|
return TRUE;
|
|
}
|
|
/*
|
|
* They rejected the packet; make sure they didn't also request
|
|
* desegmentation (we could just override the request, but
|
|
* rejecting a packet *and* requesting desegmentation is a sign
|
|
* of the dissector's code needing clearer thought, so we fail
|
|
* so that the problem is made more obvious).
|
|
*/
|
|
DISSECTOR_ASSERT(save_desegment_offset == pinfo->desegment_offset &&
|
|
save_desegment_len == pinfo->desegment_len);
|
|
}
|
|
|
|
/* Do lookups with the subdissector table.
|
|
We try the port number with the lower value first, followed by the
|
|
port number with the higher value. This means that, for packets
|
|
where a dissector is registered for *both* port numbers:
|
|
|
|
1) we pick the same dissector for traffic going in both directions;
|
|
|
|
2) we prefer the port number that's more likely to be the right
|
|
one (as that prefers well-known ports to reserved ports);
|
|
|
|
although there is, of course, no guarantee that any such strategy
|
|
will always pick the right port number.
|
|
|
|
XXX - we ignore port numbers of 0, as some dissectors use a port
|
|
number of 0 to disable the port. */
|
|
if (src_port > dst_port) {
|
|
low_port = dst_port;
|
|
high_port = src_port;
|
|
} else {
|
|
low_port = src_port;
|
|
high_port = dst_port;
|
|
}
|
|
if (low_port != 0 &&
|
|
dissector_try_port(subdissector_table, low_port, next_tvb, pinfo, tree)){
|
|
pinfo->want_pdu_tracking -= !!(pinfo->want_pdu_tracking);
|
|
return TRUE;
|
|
}
|
|
if (high_port != 0 &&
|
|
dissector_try_port(subdissector_table, high_port, next_tvb, pinfo, tree)){
|
|
pinfo->want_pdu_tracking -= !!(pinfo->want_pdu_tracking);
|
|
return TRUE;
|
|
}
|
|
|
|
if (!try_heuristic_first) {
|
|
/* do lookup with the heuristic subdissector table */
|
|
save_desegment_offset = pinfo->desegment_offset;
|
|
save_desegment_len = pinfo->desegment_len;
|
|
if (dissector_try_heuristic(heur_subdissector_list, next_tvb, pinfo, tree)){
|
|
pinfo->want_pdu_tracking -= !!(pinfo->want_pdu_tracking);
|
|
return TRUE;
|
|
}
|
|
/*
|
|
* They rejected the packet; make sure they didn't also request
|
|
* desegmentation (we could just override the request, but
|
|
* rejecting a packet *and* requesting desegmentation is a sign
|
|
* of the dissector's code needing clearer thought, so we fail
|
|
* so that the problem is made more obvious).
|
|
*/
|
|
DISSECTOR_ASSERT(save_desegment_offset == pinfo->desegment_offset &&
|
|
save_desegment_len == pinfo->desegment_len);
|
|
}
|
|
|
|
/* Oh, well, we don't know this; dissect it as data. */
|
|
call_dissector(data_handle,next_tvb, pinfo, tree);
|
|
|
|
pinfo->want_pdu_tracking -= !!(pinfo->want_pdu_tracking);
|
|
return FALSE;
|
|
}
|
|
|
|
static void
|
|
process_tcp_payload(tvbuff_t *tvb, volatile int offset, packet_info *pinfo,
|
|
proto_tree *tree, proto_tree *tcp_tree, int src_port, int dst_port,
|
|
guint32 seq, guint32 nxtseq, gboolean is_tcp_segment,
|
|
struct tcp_analysis *tcpd)
|
|
{
|
|
pinfo->want_pdu_tracking=0;
|
|
|
|
TRY {
|
|
if(is_tcp_segment){
|
|
/*qqq see if it is an unaligned PDU */
|
|
if(tcp_analyze_seq && (!tcp_desegment)){
|
|
if(seq || nxtseq){
|
|
offset=scan_for_next_pdu(tvb, tcp_tree, pinfo, offset,
|
|
seq, nxtseq, tcpd);
|
|
}
|
|
}
|
|
}
|
|
/* if offset is -1 this means that this segment is known
|
|
* to be fully inside a previously detected pdu
|
|
* so we dont even need to try to dissect it either.
|
|
*/
|
|
if( (offset!=-1) &&
|
|
decode_tcp_ports(tvb, offset, pinfo, tree, src_port,
|
|
dst_port, tcpd) ){
|
|
/*
|
|
* We succeeded in handing off to a subdissector.
|
|
*
|
|
* Is this a TCP segment or a reassembled chunk of
|
|
* TCP payload?
|
|
*/
|
|
if(is_tcp_segment){
|
|
/* if !visited, check want_pdu_tracking and
|
|
store it in table */
|
|
if((!pinfo->fd->flags.visited) &&
|
|
tcp_analyze_seq && pinfo->want_pdu_tracking){
|
|
if(seq || nxtseq){
|
|
pdu_store_sequencenumber_of_next_pdu(
|
|
pinfo,
|
|
seq,
|
|
nxtseq+pinfo->bytes_until_next_pdu,
|
|
tcpd);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
CATCH_ALL {
|
|
/* We got an exception. At this point the dissection is
|
|
* completely aborted and execution will be transfered back
|
|
* to (probably) the frame dissector.
|
|
* Here we have to place whatever we want the dissector
|
|
* to do before aborting the tcp dissection.
|
|
*/
|
|
/*
|
|
* Is this a TCP segment or a reassembled chunk of TCP
|
|
* payload?
|
|
*/
|
|
if(is_tcp_segment){
|
|
/*
|
|
* It's from a TCP segment.
|
|
*
|
|
* if !visited, check want_pdu_tracking and store it
|
|
* in table
|
|
*/
|
|
if((!pinfo->fd->flags.visited) && tcp_analyze_seq && pinfo->want_pdu_tracking){
|
|
if(seq || nxtseq){
|
|
pdu_store_sequencenumber_of_next_pdu(pinfo,
|
|
seq,
|
|
nxtseq+pinfo->bytes_until_next_pdu,
|
|
tcpd);
|
|
}
|
|
}
|
|
}
|
|
RETHROW;
|
|
}
|
|
ENDTRY;
|
|
}
|
|
|
|
void
|
|
dissect_tcp_payload(tvbuff_t *tvb, packet_info *pinfo, int offset, guint32 seq,
|
|
guint32 nxtseq, guint32 sport, guint32 dport,
|
|
proto_tree *tree, proto_tree *tcp_tree,
|
|
struct tcp_analysis *tcpd)
|
|
{
|
|
gboolean save_fragmented;
|
|
|
|
/* Can we desegment this segment? */
|
|
if (pinfo->can_desegment) {
|
|
/* Yes. */
|
|
desegment_tcp(tvb, pinfo, offset, seq, nxtseq, sport, dport, tree,
|
|
tcp_tree, tcpd);
|
|
} else {
|
|
/* No - just call the subdissector.
|
|
Mark this as fragmented, so if somebody throws an exception,
|
|
we don't report it as a malformed frame. */
|
|
save_fragmented = pinfo->fragmented;
|
|
pinfo->fragmented = TRUE;
|
|
process_tcp_payload(tvb, offset, pinfo, tree, tcp_tree, sport, dport,
|
|
seq, nxtseq, TRUE, tcpd);
|
|
pinfo->fragmented = save_fragmented;
|
|
}
|
|
}
|
|
|
|
static void
|
|
dissect_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
|
|
{
|
|
guint8 th_off_x2; /* combines th_off and th_x2 */
|
|
guint16 th_sum;
|
|
guint16 th_urp;
|
|
proto_tree *tcp_tree = NULL, *field_tree = NULL;
|
|
proto_item *ti = NULL, *tf;
|
|
int offset = 0;
|
|
gchar *flags = "<None>";
|
|
const gchar *fstr[] = {"FIN", "SYN", "RST", "PSH", "ACK", "URG", "ECN", "CWR" };
|
|
size_t fpos = 0, returned_length;
|
|
gint i;
|
|
guint bpos;
|
|
guint optlen;
|
|
guint32 nxtseq = 0;
|
|
guint reported_len;
|
|
vec_t cksum_vec[4];
|
|
guint32 phdr[2];
|
|
guint16 computed_cksum;
|
|
guint16 real_window;
|
|
guint length_remaining;
|
|
gboolean desegment_ok;
|
|
struct tcpinfo tcpinfo;
|
|
struct tcpheader *tcph;
|
|
proto_item *tf_syn = NULL, *tf_fin = NULL, *tf_rst = NULL;
|
|
struct tcp_analysis *tcpd=NULL;
|
|
|
|
tcph=ep_alloc(sizeof(struct tcpheader));
|
|
SET_ADDRESS(&tcph->ip_src, pinfo->src.type, pinfo->src.len, pinfo->src.data);
|
|
SET_ADDRESS(&tcph->ip_dst, pinfo->dst.type, pinfo->dst.len, pinfo->dst.data);
|
|
|
|
if (check_col(pinfo->cinfo, COL_PROTOCOL))
|
|
col_set_str(pinfo->cinfo, COL_PROTOCOL, "TCP");
|
|
|
|
/* Clear out the Info column. */
|
|
if (check_col(pinfo->cinfo, COL_INFO))
|
|
col_clear(pinfo->cinfo, COL_INFO);
|
|
|
|
tcph->th_sport = tvb_get_ntohs(tvb, offset);
|
|
tcph->th_dport = tvb_get_ntohs(tvb, offset + 2);
|
|
if (check_col(pinfo->cinfo, COL_INFO)) {
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, "%s > %s",
|
|
get_tcp_port(tcph->th_sport), get_tcp_port(tcph->th_dport));
|
|
}
|
|
if (tree) {
|
|
if (tcp_summary_in_tree) {
|
|
ti = proto_tree_add_protocol_format(tree, proto_tcp, tvb, 0, -1,
|
|
"Transmission Control Protocol, Src Port: %s (%u), Dst Port: %s (%u)",
|
|
get_tcp_port(tcph->th_sport), tcph->th_sport,
|
|
get_tcp_port(tcph->th_dport), tcph->th_dport);
|
|
}
|
|
else {
|
|
ti = proto_tree_add_item(tree, proto_tcp, tvb, 0, -1, FALSE);
|
|
}
|
|
tcp_tree = proto_item_add_subtree(ti, ett_tcp);
|
|
proto_tree_add_uint_format(tcp_tree, hf_tcp_srcport, tvb, offset, 2, tcph->th_sport,
|
|
"Source port: %s (%u)", get_tcp_port(tcph->th_sport), tcph->th_sport);
|
|
proto_tree_add_uint_format(tcp_tree, hf_tcp_dstport, tvb, offset + 2, 2, tcph->th_dport,
|
|
"Destination port: %s (%u)", get_tcp_port(tcph->th_dport), tcph->th_dport);
|
|
proto_tree_add_uint_hidden(tcp_tree, hf_tcp_port, tvb, offset, 2, tcph->th_sport);
|
|
proto_tree_add_uint_hidden(tcp_tree, hf_tcp_port, tvb, offset + 2, 2, tcph->th_dport);
|
|
}
|
|
|
|
/* Set the source and destination port numbers as soon as we get them,
|
|
so that they're available to the "Follow TCP Stream" code even if
|
|
we throw an exception dissecting the rest of the TCP header. */
|
|
pinfo->ptype = PT_TCP;
|
|
pinfo->srcport = tcph->th_sport;
|
|
pinfo->destport = tcph->th_dport;
|
|
|
|
tcph->th_seq = tvb_get_ntohl(tvb, offset + 4);
|
|
tcph->th_ack = tvb_get_ntohl(tvb, offset + 8);
|
|
th_off_x2 = tvb_get_guint8(tvb, offset + 12);
|
|
tcph->th_flags = tvb_get_guint8(tvb, offset + 13);
|
|
tcph->th_win = tvb_get_ntohs(tvb, offset + 14);
|
|
real_window = tcph->th_win;
|
|
tcph->th_hlen = hi_nibble(th_off_x2) * 4; /* TCP header length, in bytes */
|
|
|
|
/* find(or create if needed) the conversation for this tcp session */
|
|
tcpd=get_tcp_conversation_data(pinfo);
|
|
|
|
/*
|
|
* If we've been handed an IP fragment, we don't know how big the TCP
|
|
* segment is, so don't do anything that requires that we know that.
|
|
*
|
|
* The same applies if we're part of an error packet. (XXX - if the
|
|
* ICMP and ICMPv6 dissectors could set a "this is how big the IP
|
|
* header says it is" length in the tvbuff, we could use that; such
|
|
* a length might also be useful for handling packets where the IP
|
|
* length is bigger than the actual data available in the frame; the
|
|
* dissectors should trust that length, and then throw a
|
|
* ReportedBoundsError exception when they go past the end of the frame.)
|
|
*
|
|
* We also can't determine the segment length if the reported length
|
|
* of the TCP packet is less than the TCP header length.
|
|
*/
|
|
reported_len = tvb_reported_length(tvb);
|
|
|
|
if (!pinfo->fragmented && !pinfo->in_error_pkt) {
|
|
if (reported_len < tcph->th_hlen) {
|
|
proto_item *pi;
|
|
pi = proto_tree_add_text(tcp_tree, tvb, offset, 0,
|
|
"Short segment. Segment/fragment does not contain a full TCP header"
|
|
" (might be NMAP or someone else deliberately sending unusual packets)");
|
|
PROTO_ITEM_SET_GENERATED(pi);
|
|
expert_add_info_format(pinfo, pi, PI_MALFORMED, PI_WARN, "Short segment");
|
|
tcph->th_have_seglen = FALSE;
|
|
} else {
|
|
/* Compute the length of data in this segment. */
|
|
tcph->th_seglen = reported_len - tcph->th_hlen;
|
|
tcph->th_have_seglen = TRUE;
|
|
|
|
if (tree) { /* Add the seglen as an invisible field */
|
|
|
|
proto_tree_add_uint_hidden(ti, hf_tcp_len, tvb, offset, 4, tcph->th_seglen);
|
|
|
|
}
|
|
|
|
|
|
/* handle TCP seq# analysis parse all new segments we see */
|
|
if(tcp_analyze_seq){
|
|
if(!(pinfo->fd->flags.visited)){
|
|
tcp_analyze_sequence_number(pinfo, tcph->th_seq, tcph->th_ack, tcph->th_seglen, tcph->th_flags, tcph->th_win, tcpd);
|
|
}
|
|
if(tcp_relative_seq){
|
|
tcp_get_relative_seq_ack(&(tcph->th_seq), &(tcph->th_ack), &(tcph->th_win), tcpd);
|
|
}
|
|
}
|
|
|
|
/* Compute the sequence number of next octet after this segment. */
|
|
nxtseq = tcph->th_seq + tcph->th_seglen;
|
|
}
|
|
} else
|
|
tcph->th_have_seglen = FALSE;
|
|
|
|
if (check_col(pinfo->cinfo, COL_INFO) || tree) {
|
|
#define MAX_FLAGS_LEN 64
|
|
flags=ep_alloc(MAX_FLAGS_LEN);
|
|
flags[0]=0;
|
|
for (i = 0; i < 8; i++) {
|
|
bpos = 1 << i;
|
|
if (tcph->th_flags & bpos) {
|
|
returned_length = g_snprintf(&flags[fpos], MAX_FLAGS_LEN-fpos, "%s%s",
|
|
fpos?", ":"",
|
|
fstr[i]);
|
|
fpos += MIN(returned_length, MAX_FLAGS_LEN-fpos);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (check_col(pinfo->cinfo, COL_INFO)) {
|
|
if(tcph->th_flags&TH_ACK){
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, " [%s] Seq=%u Ack=%u Win=%u",
|
|
flags, tcph->th_seq, tcph->th_ack, tcph->th_win);
|
|
} else {
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, " [%s] Seq=%u",
|
|
flags, tcph->th_seq);
|
|
}
|
|
}
|
|
|
|
if (tree) {
|
|
if (tcp_summary_in_tree) {
|
|
proto_item_append_text(ti, ", Seq: %u", tcph->th_seq);
|
|
}
|
|
if(tcp_relative_seq){
|
|
proto_tree_add_uint_format(tcp_tree, hf_tcp_seq, tvb, offset + 4, 4, tcph->th_seq, "Sequence number: %u (relative sequence number)", tcph->th_seq);
|
|
} else {
|
|
proto_tree_add_uint(tcp_tree, hf_tcp_seq, tvb, offset + 4, 4, tcph->th_seq);
|
|
}
|
|
}
|
|
|
|
if (tcph->th_hlen < TCPH_MIN_LEN) {
|
|
/* Give up at this point; we put the source and destination port in
|
|
the tree, before fetching the header length, so that they'll
|
|
show up if this is in the failing packet in an ICMP error packet,
|
|
but it's now time to give up if the header length is bogus. */
|
|
if (check_col(pinfo->cinfo, COL_INFO))
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, ", bogus TCP header length (%u, must be at least %u)",
|
|
tcph->th_hlen, TCPH_MIN_LEN);
|
|
if (tree) {
|
|
proto_tree_add_uint_format(tcp_tree, hf_tcp_hdr_len, tvb, offset + 12, 1, tcph->th_hlen,
|
|
"Header length: %u bytes (bogus, must be at least %u)", tcph->th_hlen,
|
|
TCPH_MIN_LEN);
|
|
}
|
|
return;
|
|
}
|
|
|
|
if (tree) {
|
|
if (tcp_summary_in_tree) {
|
|
if(tcph->th_flags&TH_ACK){
|
|
proto_item_append_text(ti, ", Ack: %u", tcph->th_ack);
|
|
}
|
|
if (tcph->th_have_seglen)
|
|
proto_item_append_text(ti, ", Len: %u", tcph->th_seglen);
|
|
}
|
|
proto_item_set_len(ti, tcph->th_hlen);
|
|
if (tcph->th_have_seglen) {
|
|
if (nxtseq != tcph->th_seq) {
|
|
if(tcp_relative_seq){
|
|
tf=proto_tree_add_uint_format(tcp_tree, hf_tcp_nxtseq, tvb, offset, 0, nxtseq, "Next sequence number: %u (relative sequence number)", nxtseq);
|
|
} else {
|
|
tf=proto_tree_add_uint(tcp_tree, hf_tcp_nxtseq, tvb, offset, 0, nxtseq);
|
|
}
|
|
PROTO_ITEM_SET_GENERATED(tf);
|
|
}
|
|
}
|
|
if (tcph->th_flags & TH_ACK) {
|
|
if(tcp_relative_seq){
|
|
proto_tree_add_uint_format(tcp_tree, hf_tcp_ack, tvb, offset + 8, 4, tcph->th_ack, "Acknowledgement number: %u (relative ack number)", tcph->th_ack);
|
|
} else {
|
|
proto_tree_add_uint(tcp_tree, hf_tcp_ack, tvb, offset + 8, 4, tcph->th_ack);
|
|
}
|
|
}
|
|
proto_tree_add_uint_format(tcp_tree, hf_tcp_hdr_len, tvb, offset + 12, 1, tcph->th_hlen,
|
|
"Header length: %u bytes", tcph->th_hlen);
|
|
tf = proto_tree_add_uint_format(tcp_tree, hf_tcp_flags, tvb, offset + 13, 1,
|
|
tcph->th_flags, "Flags: 0x%02x (%s)", tcph->th_flags, flags);
|
|
field_tree = proto_item_add_subtree(tf, ett_tcp_flags);
|
|
proto_tree_add_boolean(field_tree, hf_tcp_flags_cwr, tvb, offset + 13, 1, tcph->th_flags);
|
|
proto_tree_add_boolean(field_tree, hf_tcp_flags_ecn, tvb, offset + 13, 1, tcph->th_flags);
|
|
proto_tree_add_boolean(field_tree, hf_tcp_flags_urg, tvb, offset + 13, 1, tcph->th_flags);
|
|
proto_tree_add_boolean(field_tree, hf_tcp_flags_ack, tvb, offset + 13, 1, tcph->th_flags);
|
|
proto_tree_add_boolean(field_tree, hf_tcp_flags_push, tvb, offset + 13, 1, tcph->th_flags);
|
|
tf_rst = proto_tree_add_boolean(field_tree, hf_tcp_flags_reset, tvb, offset + 13, 1, tcph->th_flags);
|
|
tf_syn = proto_tree_add_boolean(field_tree, hf_tcp_flags_syn, tvb, offset + 13, 1, tcph->th_flags);
|
|
tf_fin = proto_tree_add_boolean(field_tree, hf_tcp_flags_fin, tvb, offset + 13, 1, tcph->th_flags);
|
|
if(tcp_relative_seq
|
|
&& (tcph->th_win!=real_window)
|
|
&& !(tcph->th_flags&TH_SYN) ){ /* SYNs are never scaled */
|
|
proto_tree_add_uint_format(tcp_tree, hf_tcp_window_size, tvb, offset + 14, 2, tcph->th_win, "Window size: %u (scaled)", tcph->th_win);
|
|
} else {
|
|
proto_tree_add_uint(tcp_tree, hf_tcp_window_size, tvb, offset + 14, 2, real_window);
|
|
}
|
|
}
|
|
|
|
if(tcph->th_flags & TH_SYN) {
|
|
if(tcph->th_flags & TH_ACK)
|
|
expert_add_info_format(pinfo, tf_syn, PI_SEQUENCE, PI_CHAT, "Connection establish acknowledge (SYN+ACK): server port %s",
|
|
get_tcp_port(tcph->th_sport));
|
|
else
|
|
expert_add_info_format(pinfo, tf_syn, PI_SEQUENCE, PI_CHAT, "Connection establish request (SYN): server port %s",
|
|
get_tcp_port(tcph->th_dport));
|
|
}
|
|
if(tcph->th_flags & TH_FIN)
|
|
/* XXX - find a way to know the server port and output only that one */
|
|
expert_add_info_format(pinfo, tf_fin, PI_SEQUENCE, PI_CHAT, "Connection finish (FIN)");
|
|
if(tcph->th_flags & TH_RST)
|
|
/* XXX - find a way to know the server port and output only that one */
|
|
expert_add_info_format(pinfo, tf_rst, PI_SEQUENCE, PI_CHAT, "Connection reset (RST)");
|
|
|
|
/* Supply the sequence number of the first byte and of the first byte
|
|
after the segment. */
|
|
tcpinfo.seq = tcph->th_seq;
|
|
tcpinfo.nxtseq = nxtseq;
|
|
|
|
/* Assume we'll pass un-reassembled data to subdissectors. */
|
|
tcpinfo.is_reassembled = FALSE;
|
|
|
|
pinfo->private_data = &tcpinfo;
|
|
|
|
/*
|
|
* Assume, initially, that we can't desegment.
|
|
*/
|
|
pinfo->can_desegment = 0;
|
|
th_sum = tvb_get_ntohs(tvb, offset + 16);
|
|
if (!pinfo->fragmented && tvb_bytes_exist(tvb, 0, reported_len)) {
|
|
/* The packet isn't part of an un-reassembled fragmented datagram
|
|
and isn't truncated. This means we have all the data, and thus
|
|
can checksum it and, unless it's being returned in an error
|
|
packet, are willing to allow subdissectors to request reassembly
|
|
on it. */
|
|
|
|
if (tcp_check_checksum) {
|
|
/* We haven't turned checksum checking off; checksum it. */
|
|
|
|
/* Set up the fields of the pseudo-header. */
|
|
cksum_vec[0].ptr = pinfo->src.data;
|
|
cksum_vec[0].len = pinfo->src.len;
|
|
cksum_vec[1].ptr = pinfo->dst.data;
|
|
cksum_vec[1].len = pinfo->dst.len;
|
|
cksum_vec[2].ptr = (const guint8 *)&phdr;
|
|
switch (pinfo->src.type) {
|
|
|
|
case AT_IPv4:
|
|
phdr[0] = g_htonl((IP_PROTO_TCP<<16) + reported_len);
|
|
cksum_vec[2].len = 4;
|
|
break;
|
|
|
|
case AT_IPv6:
|
|
phdr[0] = g_htonl(reported_len);
|
|
phdr[1] = g_htonl(IP_PROTO_TCP);
|
|
cksum_vec[2].len = 8;
|
|
break;
|
|
|
|
default:
|
|
/* TCP runs only atop IPv4 and IPv6.... */
|
|
DISSECTOR_ASSERT_NOT_REACHED();
|
|
break;
|
|
}
|
|
cksum_vec[3].ptr = tvb_get_ptr(tvb, offset, reported_len);
|
|
cksum_vec[3].len = reported_len;
|
|
computed_cksum = in_cksum(&cksum_vec[0], 4);
|
|
if (computed_cksum == 0) {
|
|
proto_tree_add_uint_format(tcp_tree, hf_tcp_checksum, tvb,
|
|
offset + 16, 2, th_sum, "Checksum: 0x%04x [correct]", th_sum);
|
|
|
|
/* Checksum is valid, so we're willing to desegment it. */
|
|
desegment_ok = TRUE;
|
|
} else if (th_sum == 0) {
|
|
/* checksum is probably fine but checksum offload is used */
|
|
proto_tree_add_uint_format(tcp_tree, hf_tcp_checksum, tvb,
|
|
offset + 16, 2, th_sum, "Checksum: 0x%04x [Checksum Offloaded]", th_sum);
|
|
|
|
/* Checksum is (probably) valid, so we're willing to desegment it. */
|
|
desegment_ok = TRUE;
|
|
} else {
|
|
proto_item *item;
|
|
|
|
item = proto_tree_add_uint_format(tcp_tree, hf_tcp_checksum, tvb,
|
|
offset + 16, 2, th_sum,
|
|
"Checksum: 0x%04x [incorrect, should be 0x%04x (maybe caused by checksum offloading?)]", th_sum,
|
|
in_cksum_shouldbe(th_sum, computed_cksum));
|
|
expert_add_info_format(pinfo, item, PI_CHECKSUM, PI_ERROR, "Bad checksum");
|
|
item = proto_tree_add_boolean(tcp_tree, hf_tcp_checksum_bad, tvb,
|
|
offset + 16, 2, TRUE);
|
|
PROTO_ITEM_SET_GENERATED(item);
|
|
/* XXX - don't use hidden fields for checksums */
|
|
PROTO_ITEM_SET_HIDDEN(item);
|
|
|
|
if (check_col(pinfo->cinfo, COL_INFO))
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, " [TCP CHECKSUM INCORRECT]");
|
|
|
|
/* Checksum is invalid, so we're not willing to desegment it. */
|
|
desegment_ok = FALSE;
|
|
pinfo->noreassembly_reason = " [incorrect TCP checksum]";
|
|
}
|
|
} else {
|
|
proto_tree_add_uint_format(tcp_tree, hf_tcp_checksum, tvb,
|
|
offset + 16, 2, th_sum, "Checksum: 0x%04x [validation disabled]", th_sum);
|
|
|
|
/* We didn't check the checksum, and don't care if it's valid,
|
|
so we're willing to desegment it. */
|
|
desegment_ok = TRUE;
|
|
}
|
|
} else {
|
|
/* We don't have all the packet data, so we can't checksum it... */
|
|
proto_tree_add_uint_format(tcp_tree, hf_tcp_checksum, tvb,
|
|
offset + 16, 2, th_sum, "Checksum: 0x%04x [unchecked, not all data available]", th_sum);
|
|
|
|
/* ...and aren't willing to desegment it. */
|
|
desegment_ok = FALSE;
|
|
}
|
|
|
|
if (desegment_ok) {
|
|
/* We're willing to desegment this. Is desegmentation enabled? */
|
|
if (tcp_desegment) {
|
|
/* Yes - is this segment being returned in an error packet? */
|
|
if (!pinfo->in_error_pkt) {
|
|
/* No - indicate that we will desegment.
|
|
We do NOT want to desegment segments returned in error
|
|
packets, as they're not part of a TCP connection. */
|
|
pinfo->can_desegment = 2;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (tcph->th_flags & TH_URG) {
|
|
th_urp = tvb_get_ntohs(tvb, offset + 18);
|
|
/* Export the urgent pointer, for the benefit of protocols such as
|
|
rlogin. */
|
|
tcpinfo.urgent = TRUE;
|
|
tcpinfo.urgent_pointer = th_urp;
|
|
if (check_col(pinfo->cinfo, COL_INFO))
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, " Urg=%u", th_urp);
|
|
if (tcp_tree != NULL)
|
|
proto_tree_add_uint(tcp_tree, hf_tcp_urgent_pointer, tvb, offset + 18, 2, th_urp);
|
|
} else
|
|
tcpinfo.urgent = FALSE;
|
|
|
|
if (tcph->th_have_seglen) {
|
|
if (check_col(pinfo->cinfo, COL_INFO))
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, " Len=%u", tcph->th_seglen);
|
|
}
|
|
|
|
/* Decode TCP options, if any. */
|
|
if (tcph->th_hlen > TCPH_MIN_LEN) {
|
|
/* There's more than just the fixed-length header. Decode the
|
|
options. */
|
|
optlen = tcph->th_hlen - TCPH_MIN_LEN; /* length of options, in bytes */
|
|
tvb_ensure_bytes_exist(tvb, offset + 20, optlen);
|
|
if (tcp_tree != NULL) {
|
|
tf = proto_tree_add_text(tcp_tree, tvb, offset + 20, optlen,
|
|
"Options: (%u bytes)", optlen);
|
|
field_tree = proto_item_add_subtree(tf, ett_tcp_options);
|
|
} else
|
|
field_tree = NULL;
|
|
dissect_ip_tcp_options(tvb, offset + 20, optlen,
|
|
tcpopts, N_TCP_OPTS, TCPOPT_EOL, pinfo, field_tree);
|
|
}
|
|
|
|
/* If there was window scaling in the SYN packet but none in the SYN+ACK
|
|
* then we should just forget about the windowscaling completely.
|
|
*/
|
|
if(!pinfo->fd->flags.visited){
|
|
if(tcp_analyze_seq && tcp_relative_seq){
|
|
if((tcph->th_flags & (TH_SYN|TH_ACK))==(TH_SYN|TH_ACK)) {
|
|
verify_tcp_window_scaling(tcpd);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Skip over header + options */
|
|
offset += tcph->th_hlen;
|
|
|
|
/* Check the packet length to see if there's more data
|
|
(it could be an ACK-only packet) */
|
|
length_remaining = tvb_length_remaining(tvb, offset);
|
|
|
|
if (tcph->th_have_seglen) {
|
|
if( data_out_file ) {
|
|
reassemble_tcp( tcph->th_seq, /* sequence number */
|
|
tcph->th_seglen, /* data length */
|
|
tvb_get_ptr(tvb, offset, length_remaining), /* data */
|
|
length_remaining, /* captured data length */
|
|
( tcph->th_flags & TH_SYN ), /* is syn set? */
|
|
&pinfo->net_src,
|
|
&pinfo->net_dst,
|
|
pinfo->srcport,
|
|
pinfo->destport);
|
|
}
|
|
}
|
|
|
|
/* handle TCP seq# analysis, print any extra SEQ/ACK data for this segment*/
|
|
if(tcp_analyze_seq){
|
|
tcp_print_sequence_number_analysis(pinfo, tvb, tcp_tree, tcpd);
|
|
}
|
|
tap_queue_packet(tcp_tap, pinfo, tcph);
|
|
|
|
|
|
/* A FIN packet might complete reassembly so we need to explicitely
|
|
* check for this here.
|
|
* If this segment completes reassembly we add the FIN as a final dummy
|
|
* byte to the reassembled PDU and check if reassembly completed successfully
|
|
*/
|
|
if( (tcph->th_flags & TH_FIN)
|
|
&& (tcpd->fwd->flags&TCP_FLOW_REASSEMBLE_UNTIL_FIN) ){
|
|
struct tcp_multisegment_pdu *msp;
|
|
|
|
/* find the most previous PDU starting before this sequence number */
|
|
msp=se_tree_lookup32_le(tcpd->fwd->multisegment_pdus, tcph->th_seq-1);
|
|
if(msp){
|
|
fragment_data *ipfd_head;
|
|
|
|
ipfd_head = fragment_add(tvb, offset-1, pinfo, msp->first_frame,
|
|
tcp_fragment_table,
|
|
tcph->th_seq - msp->seq,
|
|
1,
|
|
FALSE );
|
|
if(ipfd_head){
|
|
tvbuff_t *next_tvb;
|
|
|
|
/* create a new TVB structure for desegmented data
|
|
* datalen-1 to strip the dummy FIN byte off
|
|
*/
|
|
next_tvb = tvb_new_real_data(ipfd_head->data, ipfd_head->datalen-1, ipfd_head->datalen-1);
|
|
|
|
/* add this tvb as a child to the original one */
|
|
tvb_set_child_real_data_tvbuff(tvb, next_tvb);
|
|
|
|
/* add desegmented data to the data source list */
|
|
add_new_data_source(pinfo, next_tvb, "Reassembled TCP");
|
|
|
|
/* call the payload dissector
|
|
* but make sure we dont offer desegmentation any more
|
|
*/
|
|
pinfo->can_desegment = 0;
|
|
|
|
process_tcp_payload(next_tvb, 0, pinfo, tree, tcp_tree, tcph->th_sport, tcph->th_dport, tcph->th_seq, nxtseq, FALSE, tcpd);
|
|
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* XXX - what, if any, of this should we do if this is included in an
|
|
* error packet? It might be nice to see the details of the packet
|
|
* that caused the ICMP error, but it might not be nice to have the
|
|
* dissector update state based on it.
|
|
* Also, we probably don't want to run TCP taps on those packets.
|
|
*/
|
|
if (length_remaining != 0) {
|
|
if (tcph->th_flags & TH_RST) {
|
|
/*
|
|
* RFC1122 says:
|
|
*
|
|
* 4.2.2.12 RST Segment: RFC-793 Section 3.4
|
|
*
|
|
* A TCP SHOULD allow a received RST segment to include data.
|
|
*
|
|
* DISCUSSION
|
|
* It has been suggested that a RST segment could contain
|
|
* ASCII text that encoded and explained the cause of the
|
|
* RST. No standard has yet been established for such
|
|
* data.
|
|
*
|
|
* so for segments with RST we just display the data as text.
|
|
*/
|
|
proto_tree_add_text(tcp_tree, tvb, offset, length_remaining,
|
|
"Reset cause: %s",
|
|
tvb_format_text(tvb, offset, length_remaining));
|
|
} else {
|
|
dissect_tcp_payload(tvb, pinfo, offset, tcph->th_seq, nxtseq,
|
|
tcph->th_sport, tcph->th_dport, tree, tcp_tree, tcpd);
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
proto_register_tcp(void)
|
|
{
|
|
static hf_register_info hf[] = {
|
|
|
|
{ &hf_tcp_srcport,
|
|
{ "Source Port", "tcp.srcport", FT_UINT16, BASE_DEC, NULL, 0x0,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_dstport,
|
|
{ "Destination Port", "tcp.dstport", FT_UINT16, BASE_DEC, NULL, 0x0,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_port,
|
|
{ "Source or Destination Port", "tcp.port", FT_UINT16, BASE_DEC, NULL, 0x0,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_seq,
|
|
{ "Sequence number", "tcp.seq", FT_UINT32, BASE_DEC, NULL, 0x0,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_nxtseq,
|
|
{ "Next sequence number", "tcp.nxtseq", FT_UINT32, BASE_DEC, NULL, 0x0,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_ack,
|
|
{ "Acknowledgement number", "tcp.ack", FT_UINT32, BASE_DEC, NULL, 0x0,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_hdr_len,
|
|
{ "Header Length", "tcp.hdr_len", FT_UINT8, BASE_DEC, NULL, 0x0,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_flags,
|
|
{ "Flags", "tcp.flags", FT_UINT8, BASE_HEX, NULL, 0x0,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_flags_cwr,
|
|
{ "Congestion Window Reduced (CWR)", "tcp.flags.cwr", FT_BOOLEAN, 8, TFS(&flags_set_truth), TH_CWR,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_flags_ecn,
|
|
{ "ECN-Echo", "tcp.flags.ecn", FT_BOOLEAN, 8, TFS(&flags_set_truth), TH_ECN,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_flags_urg,
|
|
{ "Urgent", "tcp.flags.urg", FT_BOOLEAN, 8, TFS(&flags_set_truth), TH_URG,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_flags_ack,
|
|
{ "Acknowledgment", "tcp.flags.ack", FT_BOOLEAN, 8, TFS(&flags_set_truth), TH_ACK,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_flags_push,
|
|
{ "Push", "tcp.flags.push", FT_BOOLEAN, 8, TFS(&flags_set_truth), TH_PUSH,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_flags_reset,
|
|
{ "Reset", "tcp.flags.reset", FT_BOOLEAN, 8, TFS(&flags_set_truth), TH_RST,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_flags_syn,
|
|
{ "Syn", "tcp.flags.syn", FT_BOOLEAN, 8, TFS(&flags_set_truth), TH_SYN,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_flags_fin,
|
|
{ "Fin", "tcp.flags.fin", FT_BOOLEAN, 8, TFS(&flags_set_truth), TH_FIN,
|
|
"", HFILL }},
|
|
|
|
/* 32 bits so we can present some values adjusted to window scaling */
|
|
{ &hf_tcp_window_size,
|
|
{ "Window size", "tcp.window_size", FT_UINT32, BASE_DEC, NULL, 0x0,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_checksum,
|
|
{ "Checksum", "tcp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
|
|
"Details at: http://www.wireshark.org/docs/wsug_html_chunked/ChAdvChecksums.html", HFILL }},
|
|
|
|
{ &hf_tcp_checksum_bad,
|
|
{ "Bad Checksum", "tcp.checksum_bad", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
|
|
"Maybe caused by checksum offloading, see: http://www.wireshark.org/docs/wsug_html_chunked/ChAdvChecksums.html", HFILL }},
|
|
|
|
{ &hf_tcp_analysis_flags,
|
|
{ "TCP Analysis Flags", "tcp.analysis.flags", FT_NONE, BASE_NONE, NULL, 0x0,
|
|
"This frame has some of the TCP analysis flags set", HFILL }},
|
|
|
|
{ &hf_tcp_analysis_retransmission,
|
|
{ "Retransmission", "tcp.analysis.retransmission", FT_NONE, BASE_NONE, NULL, 0x0,
|
|
"This frame is a suspected TCP retransmission", HFILL }},
|
|
|
|
{ &hf_tcp_analysis_fast_retransmission,
|
|
{ "Fast Retransmission", "tcp.analysis.fast_retransmission", FT_NONE, BASE_NONE, NULL, 0x0,
|
|
"This frame is a suspected TCP fast retransmission", HFILL }},
|
|
|
|
{ &hf_tcp_analysis_out_of_order,
|
|
{ "Out Of Order", "tcp.analysis.out_of_order", FT_NONE, BASE_NONE, NULL, 0x0,
|
|
"This frame is a suspected Out-Of-Order segment", HFILL }},
|
|
|
|
{ &hf_tcp_analysis_lost_packet,
|
|
{ "Previous Segment Lost", "tcp.analysis.lost_segment", FT_NONE, BASE_NONE, NULL, 0x0,
|
|
"A segment before this one was lost from the capture", HFILL }},
|
|
|
|
{ &hf_tcp_analysis_ack_lost_packet,
|
|
{ "ACKed Lost Packet", "tcp.analysis.ack_lost_segment", FT_NONE, BASE_NONE, NULL, 0x0,
|
|
"This frame ACKs a lost segment", HFILL }},
|
|
|
|
{ &hf_tcp_analysis_window_update,
|
|
{ "Window update", "tcp.analysis.window_update", FT_NONE, BASE_NONE, NULL, 0x0,
|
|
"This frame is a tcp window update", HFILL }},
|
|
|
|
{ &hf_tcp_analysis_window_full,
|
|
{ "Window full", "tcp.analysis.window_full", FT_NONE, BASE_NONE, NULL, 0x0,
|
|
"This segment has caused the allowed window to become 100% full", HFILL }},
|
|
|
|
{ &hf_tcp_analysis_keep_alive,
|
|
{ "Keep Alive", "tcp.analysis.keep_alive", FT_NONE, BASE_NONE, NULL, 0x0,
|
|
"This is a keep-alive segment", HFILL }},
|
|
|
|
{ &hf_tcp_analysis_keep_alive_ack,
|
|
{ "Keep Alive ACK", "tcp.analysis.keep_alive_ack", FT_NONE, BASE_NONE, NULL, 0x0,
|
|
"This is an ACK to a keep-alive segment", HFILL }},
|
|
|
|
{ &hf_tcp_analysis_duplicate_ack,
|
|
{ "Duplicate ACK", "tcp.analysis.duplicate_ack", FT_NONE, BASE_NONE, NULL, 0x0,
|
|
"This is a duplicate ACK", HFILL }},
|
|
|
|
{ &hf_tcp_analysis_duplicate_ack_num,
|
|
{ "Duplicate ACK #", "tcp.analysis.duplicate_ack_num", FT_UINT32, BASE_DEC, NULL, 0x0,
|
|
"This is duplicate ACK number #", HFILL }},
|
|
|
|
{ &hf_tcp_analysis_duplicate_ack_frame,
|
|
{ "Duplicate to the ACK in frame", "tcp.analysis.duplicate_ack_frame", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
|
|
"This is a duplicate to the ACK in frame #", HFILL }},
|
|
|
|
{ &hf_tcp_continuation_to,
|
|
{ "This is a continuation to the PDU in frame", "tcp.continuation_to", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
|
|
"This is a continuation to the PDU in frame #", HFILL }},
|
|
|
|
{ &hf_tcp_analysis_zero_window_probe,
|
|
{ "Zero Window Probe", "tcp.analysis.zero_window_probe", FT_NONE, BASE_NONE, NULL, 0x0,
|
|
"This is a zero-window-probe", HFILL }},
|
|
|
|
{ &hf_tcp_analysis_zero_window_probe_ack,
|
|
{ "Zero Window Probe Ack", "tcp.analysis.zero_window_probe_ack", FT_NONE, BASE_NONE, NULL, 0x0,
|
|
"This is an ACK to a zero-window-probe", HFILL }},
|
|
|
|
{ &hf_tcp_analysis_zero_window,
|
|
{ "Zero Window", "tcp.analysis.zero_window", FT_NONE, BASE_NONE, NULL, 0x0,
|
|
"This is a zero-window", HFILL }},
|
|
|
|
{ &hf_tcp_len,
|
|
{ "TCP Segment Len", "tcp.len", FT_UINT32, BASE_DEC, NULL, 0x0,
|
|
"", HFILL}},
|
|
|
|
{ &hf_tcp_analysis_acks_frame,
|
|
{ "This is an ACK to the segment in frame", "tcp.analysis.acks_frame", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
|
|
"Which previous segment is this an ACK for", HFILL}},
|
|
|
|
{ &hf_tcp_analysis_ack_rtt,
|
|
{ "The RTT to ACK the segment was", "tcp.analysis.ack_rtt", FT_RELATIVE_TIME, BASE_NONE, NULL, 0x0,
|
|
"How long time it took to ACK the segment (RTT)", HFILL}},
|
|
|
|
{ &hf_tcp_analysis_rto,
|
|
{ "The RTO for this segment was", "tcp.analysis.rto", FT_RELATIVE_TIME, BASE_NONE, NULL, 0x0,
|
|
"How long transmission was delayed before this segment was retransmitted (RTO)", HFILL}},
|
|
|
|
{ &hf_tcp_analysis_rto_frame,
|
|
{ "RTO based on delta from frame", "tcp.analysis.rto_frame", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
|
|
"This is the frame we measure the RTO from", HFILL }},
|
|
|
|
{ &hf_tcp_urgent_pointer,
|
|
{ "Urgent pointer", "tcp.urgent_pointer", FT_UINT16, BASE_DEC, NULL, 0x0,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_segment_overlap,
|
|
{ "Segment overlap", "tcp.segment.overlap", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
|
|
"Segment overlaps with other segments", HFILL }},
|
|
|
|
{ &hf_tcp_segment_overlap_conflict,
|
|
{ "Conflicting data in segment overlap", "tcp.segment.overlap.conflict", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
|
|
"Overlapping segments contained conflicting data", HFILL }},
|
|
|
|
{ &hf_tcp_segment_multiple_tails,
|
|
{ "Multiple tail segments found", "tcp.segment.multipletails", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
|
|
"Several tails were found when reassembling the pdu", HFILL }},
|
|
|
|
{ &hf_tcp_segment_too_long_fragment,
|
|
{ "Segment too long", "tcp.segment.toolongfragment", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
|
|
"Segment contained data past end of the pdu", HFILL }},
|
|
|
|
{ &hf_tcp_segment_error,
|
|
{ "Reassembling error", "tcp.segment.error", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
|
|
"Reassembling error due to illegal segments", HFILL }},
|
|
|
|
{ &hf_tcp_segment,
|
|
{ "TCP Segment", "tcp.segment", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
|
|
"TCP Segment", HFILL }},
|
|
|
|
{ &hf_tcp_segments,
|
|
{ "Reassembled TCP Segments", "tcp.segments", FT_NONE, BASE_NONE, NULL, 0x0,
|
|
"TCP Segments", HFILL }},
|
|
|
|
{ &hf_tcp_reassembled_in,
|
|
{ "Reassembled PDU in frame", "tcp.reassembled_in", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
|
|
"The PDU that doesn't end in this segment is reassembled in this frame", HFILL }},
|
|
|
|
{ &hf_tcp_option_mss,
|
|
{ "TCP MSS Option", "tcp.options.mss", FT_BOOLEAN,
|
|
BASE_NONE, NULL, 0x0, "TCP MSS Option", HFILL }},
|
|
|
|
{ &hf_tcp_option_mss_val,
|
|
{ "TCP MSS Option Value", "tcp.options.mss_val", FT_UINT16,
|
|
BASE_DEC, NULL, 0x0, "TCP MSS Option Value", HFILL}},
|
|
|
|
{ &hf_tcp_option_wscale,
|
|
{ "TCP Window Scale Option", "tcp.options.wscale",
|
|
FT_BOOLEAN,
|
|
BASE_NONE, NULL, 0x0, "TCP Window Option", HFILL}},
|
|
|
|
{ &hf_tcp_option_wscale_val,
|
|
{ "TCP Windows Scale Option Value", "tcp.options.wscale_val",
|
|
FT_UINT8, BASE_DEC, NULL, 0x0, "TCP Window Scale Value",
|
|
HFILL}},
|
|
|
|
{ &hf_tcp_option_sack_perm,
|
|
{ "TCP Sack Perm Option", "tcp.options.sack_perm",
|
|
FT_BOOLEAN,
|
|
BASE_NONE, NULL, 0x0, "TCP Sack Perm Option", HFILL}},
|
|
|
|
{ &hf_tcp_option_sack,
|
|
{ "TCP Sack Option", "tcp.options.sack", FT_BOOLEAN,
|
|
BASE_NONE, NULL, 0x0, "TCP Sack Option", HFILL}},
|
|
|
|
{ &hf_tcp_option_sack_sle,
|
|
{"TCP Sack Left Edge", "tcp.options.sack_le", FT_UINT32,
|
|
BASE_DEC, NULL, 0x0, "TCP Sack Left Edge", HFILL}},
|
|
|
|
{ &hf_tcp_option_sack_sre,
|
|
{"TCP Sack Right Edge", "tcp.options.sack_re", FT_UINT32,
|
|
BASE_DEC, NULL, 0x0, "TCP Sack Right Edge", HFILL}},
|
|
|
|
{ &hf_tcp_option_echo,
|
|
{ "TCP Echo Option", "tcp.options.echo", FT_BOOLEAN,
|
|
BASE_NONE, NULL, 0x0, "TCP Sack Echo", HFILL}},
|
|
|
|
{ &hf_tcp_option_echo_reply,
|
|
{ "TCP Echo Reply Option", "tcp.options.echo_reply",
|
|
FT_BOOLEAN,
|
|
BASE_NONE, NULL, 0x0, "TCP Echo Reply Option", HFILL}},
|
|
|
|
{ &hf_tcp_option_time_stamp,
|
|
{ "TCP Time Stamp Option", "tcp.options.time_stamp",
|
|
FT_BOOLEAN,
|
|
BASE_NONE, NULL, 0x0, "TCP Time Stamp Option", HFILL}},
|
|
|
|
{ &hf_tcp_option_cc,
|
|
{ "TCP CC Option", "tcp.options.cc", FT_BOOLEAN, BASE_NONE,
|
|
NULL, 0x0, "TCP CC Option", HFILL}},
|
|
|
|
{ &hf_tcp_option_ccnew,
|
|
{ "TCP CC New Option", "tcp.options.ccnew", FT_BOOLEAN,
|
|
BASE_NONE, NULL, 0x0, "TCP CC New Option", HFILL}},
|
|
|
|
{ &hf_tcp_option_ccecho,
|
|
{ "TCP CC Echo Option", "tcp.options.ccecho", FT_BOOLEAN,
|
|
BASE_NONE, NULL, 0x0, "TCP CC Echo Option", HFILL}},
|
|
|
|
{ &hf_tcp_option_md5,
|
|
{ "TCP MD5 Option", "tcp.options.md5", FT_BOOLEAN, BASE_NONE,
|
|
NULL, 0x0, "TCP MD5 Option", HFILL}},
|
|
|
|
{ &hf_tcp_pdu_time,
|
|
{ "Time until the last segment of this PDU", "tcp.pdu.time", FT_RELATIVE_TIME, BASE_NONE, NULL, 0x0,
|
|
"How long time has passed until the last frame of this PDU", HFILL}},
|
|
{ &hf_tcp_pdu_last_frame,
|
|
{ "Last frame of this PDU", "tcp.pdu.last_frame", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
|
|
"This is the last frame of the PDU starting in this segment", HFILL }},
|
|
|
|
};
|
|
static gint *ett[] = {
|
|
&ett_tcp,
|
|
&ett_tcp_flags,
|
|
&ett_tcp_options,
|
|
&ett_tcp_option_sack,
|
|
&ett_tcp_analysis_faults,
|
|
&ett_tcp_analysis,
|
|
&ett_tcp_segments,
|
|
&ett_tcp_segment
|
|
};
|
|
module_t *tcp_module;
|
|
|
|
proto_tcp = proto_register_protocol("Transmission Control Protocol",
|
|
"TCP", "tcp");
|
|
proto_register_field_array(proto_tcp, hf, array_length(hf));
|
|
proto_register_subtree_array(ett, array_length(ett));
|
|
|
|
/* subdissector code */
|
|
subdissector_table = register_dissector_table("tcp.port",
|
|
"TCP port", FT_UINT16, BASE_DEC);
|
|
register_heur_dissector_list("tcp", &heur_subdissector_list);
|
|
|
|
/* Register configuration preferences */
|
|
tcp_module = prefs_register_protocol(proto_tcp, NULL);
|
|
prefs_register_bool_preference(tcp_module, "summary_in_tree",
|
|
"Show TCP summary in protocol tree",
|
|
"Whether the TCP summary line should be shown in the protocol tree",
|
|
&tcp_summary_in_tree);
|
|
prefs_register_bool_preference(tcp_module, "check_checksum",
|
|
"Validate the TCP checksum if possible",
|
|
"Whether to validate the TCP checksum",
|
|
&tcp_check_checksum);
|
|
prefs_register_bool_preference(tcp_module, "desegment_tcp_streams",
|
|
"Allow subdissector to reassemble TCP streams",
|
|
"Whether subdissector can request TCP streams to be reassembled",
|
|
&tcp_desegment);
|
|
prefs_register_bool_preference(tcp_module, "analyze_sequence_numbers",
|
|
"Analyze TCP sequence numbers",
|
|
"Make the TCP dissector analyze TCP sequence numbers to find and flag segment retransmissions, missing segments and RTT",
|
|
&tcp_analyze_seq);
|
|
prefs_register_bool_preference(tcp_module, "relative_sequence_numbers",
|
|
"Relative sequence numbers and window scaling",
|
|
"Make the TCP dissector use relative sequence numbers instead of absolute ones. "
|
|
"To use this option you must also enable \"Analyze TCP sequence numbers\". "
|
|
"This option will also try to track and adjust the window field according to any TCP window scaling options seen.",
|
|
&tcp_relative_seq);
|
|
prefs_register_bool_preference(tcp_module, "try_heuristic_first",
|
|
"Try heuristic sub-dissectors first",
|
|
"Try to decode a packet using an heuristic sub-dissector before using a sub-dissector registered to a specific port",
|
|
&try_heuristic_first);
|
|
|
|
register_init_routine(tcp_fragment_init);
|
|
}
|
|
|
|
void
|
|
proto_reg_handoff_tcp(void)
|
|
{
|
|
dissector_handle_t tcp_handle;
|
|
|
|
tcp_handle = create_dissector_handle(dissect_tcp, proto_tcp);
|
|
dissector_add("ip.proto", IP_PROTO_TCP, tcp_handle);
|
|
data_handle = find_dissector("data");
|
|
tcp_tap = register_tap("tcp");
|
|
}
|