forked from osmocom/wireshark
![Gilbert Ramirez](/assets/img/avatar_default.png)
Also move ncp222.py, x11-fields, process-x11-fields.pl, make-reg-dotc, and make-reg-dotc.py. Adjust #include lines in files that include packet-*.h files. svn path=/trunk/; revision=11410
3248 lines
101 KiB
C
3248 lines
101 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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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@ethereal.com>
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* Copyright 1998 Gerald Combs
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*
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* 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 "in_cksum.h"
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#include <epan/packet.h>
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#include <epan/resolv.h>
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#include "ipproto.h"
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#include "ip_opts.h"
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#include "follow.h"
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#include "prefs.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 "reassemble.h"
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#include "tap.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_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_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_violation = -1;
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static int hf_tcp_continuation_to = -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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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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/* **************************************************************************
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* stuff to analyze TCP sequencenumbers for retransmissions, missing segments,
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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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static GMemChunk *tcp_unacked_chunk = NULL;
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static int tcp_unacked_count = 500; /* one for each packet until it is acked*/
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struct tcp_unacked {
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struct tcp_unacked *next;
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guint32 frame;
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guint32 seq;
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guint32 nextseq;
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nstime_t ts;
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/* this is to keep track of zero window and zero window probe */
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guint32 window;
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guint32 flags;
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};
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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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static GMemChunk *tcp_acked_chunk = NULL;
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static int tcp_acked_count = 5000; /* one for almost every other segment in the capture */
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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_VIOLATION 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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struct tcp_acked {
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guint32 frame_acked;
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nstime_t ts;
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guint16 flags;
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guint32 dupack_num; /* dup ack number */
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guint32 dupack_frame; /* dup ack to frame # */
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};
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static GHashTable *tcp_analyze_acked_table = NULL;
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static GMemChunk *tcp_rel_seq_chunk = NULL;
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static int tcp_rel_seq_count = 10000; /* one for each segment in the capture */
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struct tcp_rel_seq {
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guint32 seq_base;
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guint32 ack_base;
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gint16 win_scale;
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};
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static GHashTable *tcp_rel_seq_table = NULL;
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static GMemChunk *tcp_analysis_chunk = NULL;
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static int tcp_analysis_count = 20; /* one for each conversation */
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struct tcp_analysis {
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/* These two structs are managed based on comparing the source
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* and destination addresses and, if they're equal, comparing
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* the source and destination ports.
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*
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* If the source is greater than the destination, then stuff
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* sent from src is in ual1.
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*
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* If the source is less than the destination, then stuff
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* sent from src is in ual2.
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*
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* XXX - if the addresses and ports are equal, we don't guarantee
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* the behavior.
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*/
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struct tcp_unacked *ual1; /* UnAcked List 1*/
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guint32 base_seq1;
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struct tcp_unacked *ual2; /* UnAcked List 2*/
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guint32 base_seq2;
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gint16 win_scale1;
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gint16 win_scale2;
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guint32 ack1, ack2;
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guint32 ack1_frame, ack2_frame;
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nstime_t ack1_time, ack2_time;
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guint32 num1_acks, num2_acks;
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/* these two lists are used to track when PDUs may start
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inside a segment.
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*/
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struct tcp_next_pdu *pdu_seq1;
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struct tcp_next_pdu *pdu_seq2;
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};
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static GMemChunk *tcp_next_pdu_chunk = NULL;
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static int tcp_next_pdu_count = 20;
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struct tcp_next_pdu {
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struct tcp_next_pdu *next;
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guint32 seq;
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guint32 nxtpdu;
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guint32 first_frame;
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};
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static GHashTable *tcp_pdu_tracking_table = NULL;
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static GHashTable *tcp_pdu_skipping_table = NULL;
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static struct tcp_analysis *
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get_tcp_conversation_data(packet_info *pinfo)
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{
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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->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->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=g_mem_chunk_alloc(tcp_analysis_chunk);
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tcpd->ual1=NULL;
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tcpd->base_seq1=0;
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tcpd->win_scale1=-1;
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tcpd->ack1=0;
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tcpd->ack1_frame=0;
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tcpd->ack1_time.secs=0;
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tcpd->ack1_time.nsecs=0;
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tcpd->num1_acks=0;
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tcpd->ual2=NULL;
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tcpd->base_seq2=0;
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tcpd->win_scale2=-1;
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tcpd->ack2=0;
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tcpd->ack2_frame=0;
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tcpd->ack2_time.secs=0;
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tcpd->ack2_time.nsecs=0;
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tcpd->num2_acks=0;
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tcpd->pdu_seq1=NULL;
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tcpd->pdu_seq2=NULL;
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conversation_add_proto_data(conv, proto_tcp, tcpd);
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}
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return tcpd;
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}
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/* This function is called from the tcp analysis code to provide
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clues on how the seq and ack numbers are changed.
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To prevent the next_pdu lists from growing uncontrollable in size we
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use this function to do the following :
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IF we see an ACK then we assume that the left edge of the window has changed
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at least to this point and assuming it is rare with reordering and
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trailing duplicate/retransmitted segments, we just assume that after
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we have seen the ACK we will not see any more segments prior to the
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ACK value.
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If we will not see any segments prior to the ACK value then we can just
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delete all next_pdu entries that describe pdu's starting prior to the
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ACK.
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If this heuristics is prooved to be too simplistic we can just enhance it
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later.
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*/
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/* XXX this function should be ehnanced to handle sequence number wrapping */
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/* XXX to handle retransmissions and reordered packets maybe we should only
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discard entries that are more than (guesstimate) 50kb older than the
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specified sequence number ?
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*/
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static void
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prune_next_pdu_list(struct tcp_next_pdu **tnp, guint32 seq)
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{
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struct tcp_next_pdu *tmptnp;
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if(*tnp == NULL){
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return;
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}
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for(tmptnp=*tnp;tmptnp;tmptnp=tmptnp->next){
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if(tmptnp->nxtpdu<=seq){
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struct tcp_next_pdu *oldtnp;
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oldtnp=tmptnp;
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if(tmptnp==*tnp){
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tmptnp=tmptnp->next;
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*tnp=tmptnp;
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g_mem_chunk_free(tcp_next_pdu_chunk, oldtnp);
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if(!tmptnp){
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return;
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}
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continue;
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} else {
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for(tmptnp=*tnp;tmptnp;tmptnp=tmptnp->next){
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if(tmptnp->next==oldtnp){
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tmptnp->next=oldtnp->next;
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g_mem_chunk_free(tcp_next_pdu_chunk, oldtnp);
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break;
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}
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}
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if(!tmptnp){
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return;
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}
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}
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}
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}
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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)
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{
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struct tcp_analysis *tcpd=NULL;
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struct tcp_next_pdu *tnp=NULL;
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int direction;
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if(!pinfo->fd->flags.visited){
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/* find(or create if needed) the conversation for this tcp session */
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tcpd=get_tcp_conversation_data(pinfo);
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/* check direction and get pdu start 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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tnp=tcpd->pdu_seq1;
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} else {
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tnp=tcpd->pdu_seq2;
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}
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/* scan and see if we find any pdus starting inside this tvb */
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for(;tnp;tnp=tnp->next){
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/* XXX here we should also try to handle sequence number
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wrapping
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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>tnp->seq && nxtseq<=tnp->nxtpdu){
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g_hash_table_insert(tcp_pdu_skipping_table,
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(void *)pinfo->fd->num, (void *)tnp->first_frame);
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if (check_col(pinfo->cinfo, COL_INFO)){
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col_prepend_fstr(pinfo->cinfo, COL_INFO, "[Continuation to #%u] ",pinfo->fd->num);
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}
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proto_tree_add_uint(tcp_tree, hf_tcp_continuation_to,
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tvb, 0, 0, pinfo->fd->num);
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return -1;
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}
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if(seq<tnp->nxtpdu && nxtseq>tnp->nxtpdu){
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g_hash_table_insert(tcp_pdu_tracking_table,
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(void *)pinfo->fd->num, (void *)tnp->nxtpdu);
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offset+=tnp->nxtpdu-seq;
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break;
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}
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}
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} else {
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guint32 pduseq;
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guint32 first_frame;
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/* check if this is a segment in the middle of a pdu */
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first_frame=(guint32)g_hash_table_lookup(tcp_pdu_skipping_table, (void *)pinfo->fd->num);
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if(first_frame){
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if (check_col(pinfo->cinfo, COL_INFO)){
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col_prepend_fstr(pinfo->cinfo, COL_INFO, "[Continuation to #%u] ", first_frame);
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}
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proto_tree_add_uint(tcp_tree, hf_tcp_continuation_to,
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tvb, 0, 0, first_frame);
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return -1;
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}
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pduseq=(guint32)g_hash_table_lookup(tcp_pdu_tracking_table, (void *)pinfo->fd->num);
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if(pduseq){
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offset+=pduseq-seq;
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}
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|
}
|
|
|
|
return offset;
|
|
}
|
|
|
|
/* if we saw a PDU that extended beyond the end of the segment,
|
|
use this function to remember where the next pdu starts
|
|
*/
|
|
static void
|
|
pdu_store_sequencenumber_of_next_pdu(packet_info *pinfo, guint32 seq, guint32 nxtpdu)
|
|
{
|
|
struct tcp_analysis *tcpd=NULL;
|
|
struct tcp_next_pdu *tnp=NULL;
|
|
int direction;
|
|
|
|
/* find(or create if needed) the conversation for this tcp session */
|
|
tcpd=get_tcp_conversation_data(pinfo);
|
|
|
|
tnp=g_mem_chunk_alloc(tcp_next_pdu_chunk);
|
|
tnp->nxtpdu=nxtpdu;
|
|
tnp->seq=seq;
|
|
tnp->first_frame=pinfo->fd->num;
|
|
|
|
/* check direction and get pdu start list */
|
|
direction=CMP_ADDRESS(&pinfo->src, &pinfo->dst);
|
|
/* if the addresses are equal, match the ports instead */
|
|
if(direction==0) {
|
|
direction= (pinfo->srcport > pinfo->destport)*2-1;
|
|
}
|
|
if(direction>=0){
|
|
tnp->next=tcpd->pdu_seq1;
|
|
tcpd->pdu_seq1=tnp;
|
|
} else {
|
|
tnp->next=tcpd->pdu_seq2;
|
|
tcpd->pdu_seq2=tnp;
|
|
}
|
|
/*QQQ
|
|
Add check for ACKs and purge list of sequence numbers
|
|
already acked.
|
|
*/
|
|
}
|
|
|
|
/* if we saw a window scaling option, store it for future reference
|
|
*/
|
|
static void pdu_store_window_scale_option(packet_info *pinfo, guint8 ws)
|
|
{
|
|
struct tcp_analysis *tcpd=NULL;
|
|
int direction;
|
|
|
|
/* find(or create if needed) the conversation for this tcp session */
|
|
tcpd=get_tcp_conversation_data(pinfo);
|
|
|
|
/* check direction and get pdu start list */
|
|
direction=CMP_ADDRESS(&pinfo->src, &pinfo->dst);
|
|
/* if the addresses are equal, match the ports instead */
|
|
if(direction==0) {
|
|
direction= (pinfo->srcport > pinfo->destport)*2-1;
|
|
}
|
|
if(direction>=0){
|
|
tcpd->win_scale1=ws;
|
|
} else {
|
|
tcpd->win_scale2=ws;
|
|
}
|
|
}
|
|
|
|
static void
|
|
tcp_get_relative_seq_ack(guint32 frame, guint32 *seq, guint32 *ack, guint32 *win)
|
|
{
|
|
struct tcp_rel_seq *trs;
|
|
|
|
trs=g_hash_table_lookup(tcp_rel_seq_table, (void *)frame);
|
|
if(!trs){
|
|
return;
|
|
}
|
|
|
|
(*seq) -= trs->seq_base;
|
|
(*ack) -= trs->ack_base;
|
|
if(trs->win_scale!=-1){
|
|
(*win)<<=trs->win_scale;
|
|
}
|
|
}
|
|
|
|
static struct tcp_acked *
|
|
tcp_analyze_get_acked_struct(guint32 frame, gboolean createflag)
|
|
{
|
|
struct tcp_acked *ta;
|
|
|
|
ta=g_hash_table_lookup(tcp_analyze_acked_table, (void *)frame);
|
|
if((!ta) && createflag){
|
|
ta=g_mem_chunk_alloc(tcp_acked_chunk);
|
|
ta->frame_acked=0;
|
|
ta->ts.secs=0;
|
|
ta->ts.nsecs=0;
|
|
ta->flags=0;
|
|
ta->dupack_num=0;
|
|
ta->dupack_frame=0;
|
|
g_hash_table_insert(tcp_analyze_acked_table, (void *)frame, ta);
|
|
}
|
|
return ta;
|
|
}
|
|
|
|
static void
|
|
tcp_analyze_sequence_number(packet_info *pinfo, guint32 seq, guint32 ack, guint32 seglen, guint8 flags, guint32 window)
|
|
{
|
|
struct tcp_analysis *tcpd=NULL;
|
|
int direction;
|
|
struct tcp_unacked *ual1=NULL;
|
|
struct tcp_unacked *ual2=NULL;
|
|
struct tcp_unacked *ual=NULL;
|
|
guint32 base_seq;
|
|
guint32 base_ack;
|
|
guint32 ack1, ack2;
|
|
guint32 ack1_frame, ack2_frame;
|
|
nstime_t *ack1_time, *ack2_time;
|
|
guint32 num1_acks, num2_acks;
|
|
gint16 win_scale;
|
|
struct tcp_next_pdu **tnp=NULL;
|
|
|
|
/* find(or create if needed) the conversation for this tcp session */
|
|
tcpd=get_tcp_conversation_data(pinfo);
|
|
|
|
/* check direction and get ua lists */
|
|
direction=CMP_ADDRESS(&pinfo->src, &pinfo->dst);
|
|
/* if the addresses are equal, match the ports instead */
|
|
if(direction==0) {
|
|
direction= (pinfo->srcport > pinfo->destport)*2-1;
|
|
}
|
|
if(direction>=0){
|
|
ual1=tcpd->ual1;
|
|
ual2=tcpd->ual2;
|
|
ack1=tcpd->ack1;
|
|
ack2=tcpd->ack2;
|
|
ack1_frame=tcpd->ack1_frame;
|
|
ack2_frame=tcpd->ack2_frame;
|
|
ack1_time=&tcpd->ack1_time;
|
|
ack2_time=&tcpd->ack2_time;
|
|
num1_acks=tcpd->num1_acks;
|
|
num2_acks=tcpd->num2_acks;
|
|
tnp=&tcpd->pdu_seq2;
|
|
base_seq=(tcp_relative_seq && (ual1==NULL))?seq:tcpd->base_seq1;
|
|
base_ack=(tcp_relative_seq && (ual2==NULL))?ack:tcpd->base_seq2;
|
|
win_scale=tcpd->win_scale1;
|
|
} else {
|
|
ual1=tcpd->ual2;
|
|
ual2=tcpd->ual1;
|
|
ack1=tcpd->ack2;
|
|
ack2=tcpd->ack1;
|
|
ack1_frame=tcpd->ack2_frame;
|
|
ack2_frame=tcpd->ack1_frame;
|
|
ack1_time=&tcpd->ack2_time;
|
|
ack2_time=&tcpd->ack1_time;
|
|
num1_acks=tcpd->num2_acks;
|
|
num2_acks=tcpd->num1_acks;
|
|
tnp=&tcpd->pdu_seq1;
|
|
base_seq=(tcp_relative_seq && (ual1==NULL))?seq:tcpd->base_seq2;
|
|
base_ack=(tcp_relative_seq && (ual2==NULL))?ack:tcpd->base_seq1;
|
|
win_scale=tcpd->win_scale2;
|
|
}
|
|
|
|
if(!seglen){
|
|
if(!ack2_frame){
|
|
ack2_frame=pinfo->fd->num;
|
|
ack2=ack;
|
|
ack2_time->secs=pinfo->fd->abs_secs;
|
|
ack2_time->nsecs=pinfo->fd->abs_usecs*1000;
|
|
num2_acks=0;
|
|
} else if(GT_SEQ(ack, ack2)){
|
|
ack2_frame=pinfo->fd->num;
|
|
ack2=ack;
|
|
ack2_time->secs=pinfo->fd->abs_secs;
|
|
ack2_time->nsecs=pinfo->fd->abs_usecs*1000;
|
|
num2_acks=0;
|
|
}
|
|
}
|
|
|
|
#ifdef REMOVED
|
|
/* useful debug ouput
|
|
* it prints the two lists of the sliding window emulation
|
|
*/
|
|
{
|
|
struct tcp_unacked *u=NULL;
|
|
printf("\n");
|
|
printf("analyze_sequence_number(frame:%d seq:%d nextseq:%d ack:%d baseseq:0x%08x baseack:0x%08x)\n",pinfo->fd->num,seq,seq+seglen,ack,base_seq,base_ack);
|
|
printf("UAL1:\n");
|
|
for(u=ual1;u;u=u->next){
|
|
printf(" Frame:%d seq:%d nseq:%d time:%d.%09d ack:%d:%d\n",u->frame,u->seq,u->nextseq,u->ts.secs,u->ts.nsecs,ack1,ack2);
|
|
}
|
|
printf("UAL2:\n");
|
|
for(u=ual2;u;u=u->next){
|
|
printf(" Frame:%d seq:%d nseq:%d time:%d.%09d ack:%d:%d\n",u->frame,u->seq,u->nextseq,u->ts.secs,u->ts.nsecs,ack1,ack2);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/* To handle FIN, just add 1 to the length.
|
|
else the ACK following the FIN-ACK will look like it was
|
|
outside the window. */
|
|
if( flags&TH_FIN ){
|
|
seglen+=1;
|
|
}
|
|
|
|
/* handle the sequence numbers */
|
|
/* if this was a SYN packet, then remove existing list and
|
|
* put SEQ+1 first the list */
|
|
if(flags&TH_SYN){
|
|
for(ual=ual1;ual1;ual1=ual){
|
|
ual=ual1->next;
|
|
g_mem_chunk_free(tcp_unacked_chunk, ual1);
|
|
}
|
|
ual1=g_mem_chunk_alloc(tcp_unacked_chunk);
|
|
ual1->next=NULL;
|
|
ual1->frame=pinfo->fd->num;
|
|
ack1_frame=0;
|
|
ack2_frame=0;
|
|
ack1=0;
|
|
ack2=0;
|
|
num1_acks=0;
|
|
num2_acks=0;
|
|
ual1->seq=seq;
|
|
ual1->nextseq=seq+1;
|
|
ual1->ts.secs=pinfo->fd->abs_secs;
|
|
ual1->ts.nsecs=pinfo->fd->abs_usecs*1000;
|
|
ual1->window=window;
|
|
ual1->flags=0;
|
|
if(tcp_relative_seq){
|
|
base_seq=seq;
|
|
/* if this was an SYN|ACK packet then set base_ack
|
|
* reflect the start of the sequence, i.e. one less
|
|
*/
|
|
if(flags&TH_ACK){
|
|
base_ack=ack-1;
|
|
} else {
|
|
base_ack=ack;
|
|
}
|
|
}
|
|
goto seq_finished;
|
|
}
|
|
|
|
/* if this is the first segment we see then just add it */
|
|
if( !ual1 ){
|
|
ual1=g_mem_chunk_alloc(tcp_unacked_chunk);
|
|
ual1->next=NULL;
|
|
ual1->frame=pinfo->fd->num;
|
|
ual1->seq=seq;
|
|
ual1->nextseq=seq+seglen;
|
|
ual1->ts.secs=pinfo->fd->abs_secs;
|
|
ual1->ts.nsecs=pinfo->fd->abs_usecs*1000;
|
|
ual1->window=window;
|
|
ual1->flags=0;
|
|
if(tcp_relative_seq){
|
|
base_seq=seq;
|
|
base_ack=ack;
|
|
}
|
|
goto seq_finished;
|
|
}
|
|
|
|
/* if we get past here we know that ual1 points to a segment */
|
|
|
|
|
|
/* if seq is beyond ual1->nextseq we have lost a segment */
|
|
if (GT_SEQ(seq, ual1->nextseq)) {
|
|
struct tcp_acked *ta;
|
|
|
|
ta=tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE);
|
|
ta->flags|=TCP_A_LOST_PACKET;
|
|
|
|
/* just add the segment to the beginning of the list */
|
|
ual=g_mem_chunk_alloc(tcp_unacked_chunk);
|
|
ual->next=ual1;
|
|
ual->frame=pinfo->fd->num;
|
|
ual->seq=seq;
|
|
ual->nextseq=seq+seglen;
|
|
ual->ts.secs=pinfo->fd->abs_secs;
|
|
ual->ts.nsecs=pinfo->fd->abs_usecs*1000;
|
|
ual->window=window;
|
|
ual->flags=0;
|
|
ual1=ual;
|
|
goto seq_finished;
|
|
}
|
|
|
|
/* keep-alives are empty segments with a sequence number -1 of what
|
|
* we would expect.
|
|
*
|
|
* Solaris is an exception, Solaris does not really use KeepAlives
|
|
* according to RFC793, instead they move the left window edge one
|
|
* byte to the left and makes up a fake byte to fill in this position
|
|
* of the enlarged window.
|
|
* This means that Solaris will do "weird" KeepAlives that actually
|
|
* contains a one-byte segment with "random" junk data which the
|
|
* Solaris host then will try to transmit, and posisbly retransmit
|
|
* to the other side. Of course the other side will ignore this junk
|
|
* byte since it is outside (left of) the window.
|
|
* This is actually a brilliant trick that gives them, for free,
|
|
* semi-reliable KeepAlives.
|
|
* (since normal retransmission will handle any lost keepalive segments
|
|
* , brilliant)
|
|
*/
|
|
if( (seglen<=1) && EQ_SEQ(seq, (ual1->nextseq-1)) ){
|
|
if(!(flags&TH_FIN)){ /* FIN segments are not keepalives */
|
|
struct tcp_acked *ta;
|
|
|
|
ta=tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE);
|
|
ta->flags|=TCP_A_KEEP_ALIVE;
|
|
ual1->flags|=TCP_A_KEEP_ALIVE;
|
|
goto seq_finished;
|
|
}
|
|
}
|
|
|
|
|
|
/* if this is an empty segment, just skip it all */
|
|
if( !seglen ){
|
|
goto seq_finished;
|
|
}
|
|
|
|
/* check if the sequence number is lower than expected, i.e. either a
|
|
* retransmission a fast retransmission or an out of order segment
|
|
*/
|
|
if( LT_SEQ(seq, ual1->nextseq )){
|
|
gboolean outoforder;
|
|
struct tcp_unacked *tu,*ntu;
|
|
|
|
/* assume it is a fast retransmission if
|
|
* 1 we have seen >=3 dupacks in the other direction for this
|
|
* segment (i.e. >=4 acks)
|
|
* 2 if this segment is the next unacked segment
|
|
* 3 this segment came within 10ms of the last dupack
|
|
* (10ms is arbitrary but should be low enough not to be
|
|
* confused with a retransmission timeout
|
|
*/
|
|
if( (num1_acks>=4) && (seq==ack1) ){
|
|
guint32 t;
|
|
|
|
t=(pinfo->fd->abs_secs-ack1_time->secs)*1000000000;
|
|
t=t+(pinfo->fd->abs_usecs*1000)-ack1_time->nsecs;
|
|
if(t<10000000){
|
|
/* has to be a retransmission then */
|
|
struct tcp_acked *ta;
|
|
|
|
ta=tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE);
|
|
ta->flags|=TCP_A_FAST_RETRANSMISSION;
|
|
goto seq_finished;
|
|
}
|
|
}
|
|
|
|
/* check it is a suspected out of order segment.
|
|
* we assume it is an out of order segment if
|
|
* 1 it has not been ACKed yet.
|
|
* 2 we have not seen the segment before
|
|
* 3 it arrived within (arbitrary value) 4ms of the
|
|
* next semgent in the sequence.
|
|
* 4 there were no dupacks in the opposite direction.
|
|
*/
|
|
outoforder=TRUE;
|
|
#ifdef REMOVED
|
|
/* dont do this test. For full-duplex capture devices that
|
|
* capture in both directions using two NICs it is more common
|
|
* than one would expect for this to happen since they often
|
|
* lose the time integrity between the two NICs
|
|
*/
|
|
/* 1 has it already been ACKed ? */
|
|
if(LT_SEQ(seq,ack1)){
|
|
outoforder=FALSE;
|
|
}
|
|
#endif
|
|
/* 2 have we seen this segment before ? */
|
|
for(tu=ual1;tu;tu=tu->next){
|
|
if((tu->frame)&&(tu->seq==seq)){
|
|
outoforder=FALSE;
|
|
}
|
|
}
|
|
/* 3 was it received within 4ms of the next segment ?*/
|
|
ntu=NULL;
|
|
for(tu=ual1;tu;tu=tu->next){
|
|
if(LT_SEQ(seq,tu->seq)){
|
|
if(tu->frame){
|
|
ntu=tu;
|
|
}
|
|
}
|
|
}
|
|
if(ntu){
|
|
if(pinfo->fd->abs_secs>(guint32)(ntu->ts.secs+2)){
|
|
outoforder=FALSE;
|
|
} else if((pinfo->fd->abs_secs+2)<(guint32)ntu->ts.secs){
|
|
outoforder=FALSE;
|
|
} else {
|
|
guint32 t;
|
|
|
|
t=(ntu->ts.secs-pinfo->fd->abs_secs)*1000000000;
|
|
t=t+ntu->ts.nsecs-(pinfo->fd->abs_usecs*1000);
|
|
if(t>4000000){
|
|
outoforder=FALSE;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
if(outoforder) {
|
|
struct tcp_acked *ta;
|
|
|
|
ta=tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE);
|
|
ta->flags|=TCP_A_OUT_OF_ORDER;
|
|
} else {
|
|
/* has to be a retransmission then */
|
|
struct tcp_acked *ta;
|
|
|
|
ta=tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE);
|
|
ta->flags|=TCP_A_RETRANSMISSION;
|
|
|
|
/* did this segment contain any more data we havent seen yet?
|
|
* if so we can just increase nextseq
|
|
*/
|
|
if(GT_SEQ((seq+seglen), ual1->nextseq)){
|
|
ual1->nextseq=seq+seglen;
|
|
ual1->frame=pinfo->fd->num;
|
|
ual1->ts.secs=pinfo->fd->abs_secs;
|
|
ual1->ts.nsecs=pinfo->fd->abs_usecs*1000;
|
|
}
|
|
}
|
|
goto seq_finished;
|
|
}
|
|
|
|
/* just add the segment to the beginning of the list */
|
|
ual=g_mem_chunk_alloc(tcp_unacked_chunk);
|
|
ual->next=ual1;
|
|
ual->frame=pinfo->fd->num;
|
|
ual->seq=seq;
|
|
ual->nextseq=seq+seglen;
|
|
ual->ts.secs=pinfo->fd->abs_secs;
|
|
ual->ts.nsecs=pinfo->fd->abs_usecs*1000;
|
|
ual->window=window;
|
|
ual->flags=0;
|
|
ual1=ual;
|
|
|
|
seq_finished:
|
|
|
|
|
|
/* handle the ack numbers */
|
|
|
|
/* if we dont have the ack flag its not much we can do */
|
|
if( !(flags&TH_ACK)){
|
|
goto ack_finished;
|
|
}
|
|
|
|
/* if we havent seen anything yet in the other direction we dont
|
|
* know what this one acks */
|
|
if( !ual2 ){
|
|
goto ack_finished;
|
|
}
|
|
|
|
/* if we dont have any real segments in the other direction not
|
|
* acked yet (as we see from the magic frame==0 entry)
|
|
* then there is no point in continuing
|
|
*/
|
|
if( !ual2->frame ){
|
|
goto ack_finished;
|
|
}
|
|
|
|
/* if we get here we know ual2 is valid */
|
|
|
|
/* if we are acking beyong what we have seen in the other direction
|
|
* we must have lost packets. Not much point in keeping the segments
|
|
* in the other direction either.
|
|
*/
|
|
if( GT_SEQ(ack, ual2->nextseq )){
|
|
struct tcp_acked *ta;
|
|
|
|
ta=tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE);
|
|
ta->flags|=TCP_A_ACK_LOST_PACKET;
|
|
for(ual=ual2;ual2;ual2=ual){
|
|
ual=ual2->next;
|
|
g_mem_chunk_free(tcp_unacked_chunk, ual2);
|
|
}
|
|
prune_next_pdu_list(tnp, ack-base_ack);
|
|
goto ack_finished;
|
|
}
|
|
|
|
|
|
/* does this ACK ack all semgents we have seen in the other direction?*/
|
|
if( EQ_SEQ(ack, ual2->nextseq )){
|
|
struct tcp_acked *ta;
|
|
|
|
ta=tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE);
|
|
ta->frame_acked=ual2->frame;
|
|
ta->ts.secs=pinfo->fd->abs_secs-ual2->ts.secs;
|
|
ta->ts.nsecs=pinfo->fd->abs_usecs*1000-ual2->ts.nsecs;
|
|
if(ta->ts.nsecs<0){
|
|
ta->ts.nsecs+=1000000000;
|
|
ta->ts.secs--;
|
|
}
|
|
|
|
/* its all been ACKed so we dont need to keep them anymore */
|
|
for(ual=ual2;ual2;ual2=ual){
|
|
ual=ual2->next;
|
|
g_mem_chunk_free(tcp_unacked_chunk, ual2);
|
|
}
|
|
prune_next_pdu_list(tnp, ack-base_ack);
|
|
goto ack_finished;
|
|
}
|
|
|
|
/* ok it only ACKs part of what we have seen. Find out how much
|
|
* update and remove the ACKed segments
|
|
*/
|
|
for(ual=ual2;ual->next;ual=ual->next){
|
|
if( GE_SEQ(ack, ual->next->nextseq)){
|
|
break;
|
|
}
|
|
}
|
|
if(ual->next){
|
|
struct tcp_unacked *tmpual=NULL;
|
|
struct tcp_unacked *ackedual=NULL;
|
|
struct tcp_acked *ta;
|
|
|
|
/* XXX normal ACK*/
|
|
ackedual=ual->next;
|
|
|
|
ta=tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE);
|
|
ta->frame_acked=ackedual->frame;
|
|
ta->ts.secs=pinfo->fd->abs_secs-ackedual->ts.secs;
|
|
ta->ts.nsecs=pinfo->fd->abs_usecs*1000-ackedual->ts.nsecs;
|
|
if(ta->ts.nsecs<0){
|
|
ta->ts.nsecs+=1000000000;
|
|
ta->ts.secs--;
|
|
}
|
|
|
|
/* just delete all ACKed segments */
|
|
tmpual=ual->next;
|
|
ual->next=NULL;
|
|
for(ual=tmpual;ual;ual=tmpual){
|
|
tmpual=ual->next;
|
|
g_mem_chunk_free(tcp_unacked_chunk, ual);
|
|
}
|
|
prune_next_pdu_list(tnp, ack-base_ack);
|
|
}
|
|
|
|
ack_finished:
|
|
/* we might have deleted the entire ual2 list, if this is an ACK,
|
|
make sure ual2 at least has a dummy entry for the current ACK */
|
|
if( (!ual2) && (flags&TH_ACK) ){
|
|
ual2=g_mem_chunk_alloc(tcp_unacked_chunk);
|
|
ual2->next=NULL;
|
|
ual2->frame=0;
|
|
ual2->seq=ack;
|
|
ual2->nextseq=ack;
|
|
ual2->ts.secs=0;
|
|
ual2->ts.nsecs=0;
|
|
ual2->window=window;
|
|
ual2->flags=0;
|
|
}
|
|
|
|
/* update the ACK counter and check for
|
|
duplicate ACKs*/
|
|
/* go to the oldest segment in the list of segments
|
|
in the other direction */
|
|
/* XXX we should guarantee ual2 to always be non NULL here
|
|
so we can skip the ual/ual2 tests */
|
|
for(ual=ual2;ual&&ual->next;ual=ual->next)
|
|
;
|
|
if(ual2){
|
|
/* we only consider this being a potential duplicate ack
|
|
if the segment length is 0 (ack only segment)
|
|
and if it acks something previous to oldest segment
|
|
in the other direction */
|
|
if((!seglen)&&LE_SEQ(ack,ual->seq)){
|
|
/* if this is the first ack to keep track of, it is not
|
|
a duplicate */
|
|
if(num2_acks==0){
|
|
ack2=ack;
|
|
ack2_frame=pinfo->fd->num;
|
|
num2_acks=1;
|
|
/* if this ack is different, store this one
|
|
instead and forget the previous one(s) */
|
|
} else if(ack2!=ack){
|
|
ack2=ack;
|
|
ack2_frame=pinfo->fd->num;
|
|
num2_acks=1;
|
|
/* this has to be a duplicate ack */
|
|
} else {
|
|
num2_acks++;
|
|
}
|
|
|
|
/* is this an ACK to a KeepAlive? */
|
|
if( (ual->flags&TCP_A_KEEP_ALIVE)
|
|
&& (ack==ual->seq) ){
|
|
struct tcp_acked *ta;
|
|
ta=tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE);
|
|
ta->flags|=TCP_A_KEEP_ALIVE_ACK;
|
|
ual->flags^=TCP_A_KEEP_ALIVE;
|
|
} else if(num2_acks>1) {
|
|
/* ok we have found a potential duplicate ack */
|
|
struct tcp_acked *ta;
|
|
ta=tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE);
|
|
/* keepalives are not dupacks and
|
|
* netiher are RST/FIN segments
|
|
*/
|
|
if( (!(ta->flags&TCP_A_KEEP_ALIVE))
|
|
&&(!(flags&(TH_RST|TH_FIN))) ){
|
|
ta->flags|=TCP_A_DUPLICATE_ACK;
|
|
ta->dupack_num=num2_acks-1;
|
|
ta->dupack_frame=ack2_frame;
|
|
}
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
|
|
/* check for zero window probes
|
|
a zero window probe is when a TCP tries to write 1 byte segments
|
|
where the remote side has advertised a window of 0 bytes.
|
|
We only do this check if we actually have seen anything from the
|
|
other side of this connection.
|
|
|
|
We also assume ual still points to the last entry in the ual2
|
|
list from the section above.
|
|
|
|
At the same time, check for violations, i.e. attempts to write >1
|
|
byte to a zero-window.
|
|
*/
|
|
/* XXX we should not need to do the ual->frame check here?
|
|
might be a bug somewhere. look for it later .
|
|
*/
|
|
if(ual2&&(ual->frame)){
|
|
if((seglen==1)&&(ual->window==0)){
|
|
struct tcp_acked *ta;
|
|
ta=tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE);
|
|
ta->flags|=TCP_A_ZERO_WINDOW_PROBE;
|
|
}
|
|
if((seglen>1)&&(ual->window==0)){
|
|
struct tcp_acked *ta;
|
|
ta=tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE);
|
|
ta->flags|=TCP_A_ZERO_WINDOW_VIOLATION;
|
|
}
|
|
}
|
|
|
|
/* check for zero window
|
|
* dont check for RST/FIN segments since the window field is
|
|
* meaningless for those
|
|
*/
|
|
if( (!window)
|
|
&&(!(flags&(TH_RST|TH_FIN))) ){
|
|
struct tcp_acked *ta;
|
|
ta=tcp_analyze_get_acked_struct(pinfo->fd->num, TRUE);
|
|
ta->flags|=TCP_A_ZERO_WINDOW;
|
|
}
|
|
|
|
|
|
/* store the lists back in our struct */
|
|
if(direction>=0){
|
|
/*
|
|
* XXX - if direction == 0, that'll be true for packets
|
|
* from both sides of the connection, so this won't
|
|
* work.
|
|
*
|
|
* That'd be a connection from a given port on a machine
|
|
* to that same port on the same machine; does that ever
|
|
* happen?
|
|
*/
|
|
tcpd->ual1=ual1;
|
|
tcpd->ual2=ual2;
|
|
tcpd->ack1=ack1;
|
|
tcpd->ack2=ack2;
|
|
tcpd->ack1_frame=ack1_frame;
|
|
tcpd->ack2_frame=ack2_frame;
|
|
tcpd->num1_acks=num1_acks;
|
|
tcpd->num2_acks=num2_acks;
|
|
tcpd->base_seq1=base_seq;
|
|
tcpd->base_seq2=base_ack;
|
|
} else {
|
|
tcpd->ual1=ual2;
|
|
tcpd->ual2=ual1;
|
|
tcpd->ack1=ack2;
|
|
tcpd->ack2=ack1;
|
|
tcpd->ack1_frame=ack2_frame;
|
|
tcpd->ack2_frame=ack1_frame;
|
|
tcpd->num1_acks=num2_acks;
|
|
tcpd->num2_acks=num1_acks;
|
|
tcpd->base_seq2=base_seq;
|
|
tcpd->base_seq1=base_ack;
|
|
}
|
|
|
|
|
|
if(tcp_relative_seq){
|
|
struct tcp_rel_seq *trs;
|
|
/* remember relative seq/ack number base for this packet */
|
|
trs=g_mem_chunk_alloc(tcp_rel_seq_chunk);
|
|
trs->seq_base=base_seq;
|
|
trs->ack_base=base_ack;
|
|
trs->win_scale=win_scale;
|
|
g_hash_table_insert(tcp_rel_seq_table, (void *)pinfo->fd->num, trs);
|
|
}
|
|
}
|
|
|
|
static void
|
|
tcp_print_sequence_number_analysis(packet_info *pinfo, tvbuff_t *tvb, proto_tree *parent_tree)
|
|
{
|
|
struct tcp_acked *ta;
|
|
proto_item *item;
|
|
proto_tree *tree;
|
|
|
|
ta=tcp_analyze_get_acked_struct(pinfo->fd->num, FALSE);
|
|
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);
|
|
}
|
|
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);
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_fstr(pinfo->cinfo, COL_INFO, "[TCP Retransmission] ");
|
|
}
|
|
}
|
|
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);
|
|
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_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);
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_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);
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_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);
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_fstr(pinfo->cinfo, COL_INFO, "[TCP ACKed lost segment] ");
|
|
}
|
|
}
|
|
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);
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_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);
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_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_fstr(pinfo->cinfo, COL_INFO, "[TCP Dup ACK %d#%d] ", 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);
|
|
}
|
|
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);
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_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);
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_fstr(pinfo->cinfo, COL_INFO, "[TCP ZeroWindow] ");
|
|
}
|
|
}
|
|
if( ta->flags&TCP_A_ZERO_WINDOW_VIOLATION ){
|
|
flags_item=proto_tree_add_none_format(flags_tree, hf_tcp_analysis_zero_window_violation, tvb, 0, 0, "This is a ZeroWindow violation, attempts to write >1 byte of data to a zero-window");
|
|
PROTO_ITEM_SET_GENERATED(flags_item);
|
|
if(check_col(pinfo->cinfo, COL_INFO)){
|
|
col_prepend_fstr(pinfo->cinfo, COL_INFO, "[TCP ZeroWindowViolation] ");
|
|
}
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
|
|
/* Do we still need to do this ...remove_all() even though we dont need
|
|
* to do anything special? The glib docs are not clear on this and
|
|
* its better safe than sorry
|
|
*/
|
|
static gboolean
|
|
free_all_acked(gpointer key_arg _U_, gpointer value _U_, gpointer user_data _U_)
|
|
{
|
|
return TRUE;
|
|
}
|
|
|
|
static guint
|
|
tcp_acked_hash(gconstpointer k)
|
|
{
|
|
guint32 frame = (guint32)k;
|
|
|
|
return frame;
|
|
}
|
|
static gint
|
|
tcp_acked_equal(gconstpointer k1, gconstpointer k2)
|
|
{
|
|
guint32 frame1 = (guint32)k1;
|
|
guint32 frame2 = (guint32)k2;
|
|
|
|
return frame1==frame2;
|
|
}
|
|
|
|
static void
|
|
tcp_analyze_seq_init(void)
|
|
{
|
|
/* first destroy the tables */
|
|
if( tcp_analyze_acked_table ){
|
|
g_hash_table_foreach_remove(tcp_analyze_acked_table,
|
|
free_all_acked, NULL);
|
|
g_hash_table_destroy(tcp_analyze_acked_table);
|
|
tcp_analyze_acked_table = NULL;
|
|
}
|
|
if( tcp_rel_seq_table ){
|
|
g_hash_table_foreach_remove(tcp_rel_seq_table,
|
|
free_all_acked, NULL);
|
|
g_hash_table_destroy(tcp_rel_seq_table);
|
|
tcp_rel_seq_table = NULL;
|
|
}
|
|
if( tcp_pdu_tracking_table ){
|
|
g_hash_table_foreach_remove(tcp_pdu_tracking_table,
|
|
free_all_acked, NULL);
|
|
g_hash_table_destroy(tcp_pdu_tracking_table);
|
|
tcp_pdu_tracking_table = NULL;
|
|
}
|
|
if( tcp_pdu_skipping_table ){
|
|
g_hash_table_foreach_remove(tcp_pdu_skipping_table,
|
|
free_all_acked, NULL);
|
|
g_hash_table_destroy(tcp_pdu_skipping_table);
|
|
tcp_pdu_skipping_table = NULL;
|
|
}
|
|
|
|
/*
|
|
* Now destroy the chunk from which the conversation table
|
|
* structures were allocated.
|
|
*/
|
|
if (tcp_next_pdu_chunk) {
|
|
g_mem_chunk_destroy(tcp_next_pdu_chunk);
|
|
tcp_next_pdu_chunk = NULL;
|
|
}
|
|
if (tcp_analysis_chunk) {
|
|
g_mem_chunk_destroy(tcp_analysis_chunk);
|
|
tcp_analysis_chunk = NULL;
|
|
}
|
|
if (tcp_unacked_chunk) {
|
|
g_mem_chunk_destroy(tcp_unacked_chunk);
|
|
tcp_unacked_chunk = NULL;
|
|
}
|
|
if (tcp_acked_chunk) {
|
|
g_mem_chunk_destroy(tcp_acked_chunk);
|
|
tcp_acked_chunk = NULL;
|
|
}
|
|
if (tcp_rel_seq_chunk) {
|
|
g_mem_chunk_destroy(tcp_rel_seq_chunk);
|
|
tcp_rel_seq_chunk = NULL;
|
|
}
|
|
|
|
if(tcp_analyze_seq){
|
|
tcp_analyze_acked_table = g_hash_table_new(tcp_acked_hash,
|
|
tcp_acked_equal);
|
|
tcp_rel_seq_table = g_hash_table_new(tcp_acked_hash,
|
|
tcp_acked_equal);
|
|
tcp_pdu_tracking_table = g_hash_table_new(tcp_acked_hash,
|
|
tcp_acked_equal);
|
|
tcp_pdu_skipping_table = g_hash_table_new(tcp_acked_hash,
|
|
tcp_acked_equal);
|
|
tcp_next_pdu_chunk = g_mem_chunk_new("tcp_next_pdu_chunk",
|
|
sizeof(struct tcp_next_pdu),
|
|
tcp_next_pdu_count * sizeof(struct tcp_next_pdu),
|
|
G_ALLOC_ONLY);
|
|
tcp_analysis_chunk = g_mem_chunk_new("tcp_analysis_chunk",
|
|
sizeof(struct tcp_analysis),
|
|
tcp_analysis_count * sizeof(struct tcp_analysis),
|
|
G_ALLOC_ONLY);
|
|
tcp_unacked_chunk = g_mem_chunk_new("tcp_unacked_chunk",
|
|
sizeof(struct tcp_unacked),
|
|
tcp_unacked_count * sizeof(struct tcp_unacked),
|
|
G_ALLOC_ONLY);
|
|
tcp_acked_chunk = g_mem_chunk_new("tcp_acked_chunk",
|
|
sizeof(struct tcp_acked),
|
|
tcp_acked_count * sizeof(struct tcp_acked),
|
|
G_ALLOC_ONLY);
|
|
if(tcp_relative_seq){
|
|
tcp_rel_seq_chunk = g_mem_chunk_new("tcp_rel_seq_chunk",
|
|
sizeof(struct tcp_rel_seq),
|
|
tcp_rel_seq_count * sizeof(struct tcp_rel_seq),
|
|
G_ALLOC_ONLY);
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
/* **************************************************************************
|
|
* 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 = FALSE;
|
|
|
|
static GHashTable *tcp_segment_table = NULL;
|
|
static GMemChunk *tcp_segment_key_chunk = NULL;
|
|
static int tcp_segment_init_count = 200;
|
|
static GMemChunk *tcp_segment_address_chunk = NULL;
|
|
static int tcp_segment_address_init_count = 500;
|
|
|
|
typedef struct _tcp_segment_key {
|
|
/* for own bookkeeping inside packet-tcp.c */
|
|
address *src;
|
|
address *dst;
|
|
guint32 seq;
|
|
/* xxx */
|
|
guint16 sport;
|
|
guint16 dport;
|
|
guint32 start_seq;
|
|
guint32 tot_len;
|
|
guint32 first_frame;
|
|
} tcp_segment_key;
|
|
|
|
static gboolean
|
|
free_all_segments(gpointer key_arg, gpointer value _U_, gpointer user_data _U_)
|
|
{
|
|
tcp_segment_key *key = key_arg;
|
|
|
|
if((key->src)&&(key->src->data)){
|
|
g_free((gpointer)key->src->data);
|
|
key->src->data=NULL;
|
|
}
|
|
|
|
if((key->dst)&&(key->dst->data)){
|
|
g_free((gpointer)key->dst->data);
|
|
key->dst->data=NULL;
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
static guint
|
|
tcp_segment_hash(gconstpointer k)
|
|
{
|
|
const tcp_segment_key *key = (const tcp_segment_key *)k;
|
|
|
|
return key->seq+key->sport;
|
|
}
|
|
|
|
static gint
|
|
tcp_segment_equal(gconstpointer k1, gconstpointer k2)
|
|
{
|
|
const tcp_segment_key *key1 = (const tcp_segment_key *)k1;
|
|
const tcp_segment_key *key2 = (const tcp_segment_key *)k2;
|
|
|
|
return ( ( (key1->seq==key2->seq)
|
|
&&(ADDRESSES_EQUAL(key1->src, key2->src))
|
|
&&(ADDRESSES_EQUAL(key1->dst, key2->dst))
|
|
&&(key1->sport==key2->sport)
|
|
&&(key1->dport==key2->dport)
|
|
) ? TRUE:FALSE);
|
|
}
|
|
|
|
static void
|
|
tcp_desegment_init(void)
|
|
{
|
|
/*
|
|
* Free this before freeing any memory chunks; those
|
|
* chunks contain data we'll look at in "free_all_segments()".
|
|
*/
|
|
if(tcp_segment_table){
|
|
g_hash_table_foreach_remove(tcp_segment_table,
|
|
free_all_segments, NULL);
|
|
g_hash_table_destroy(tcp_segment_table);
|
|
tcp_segment_table = NULL;
|
|
}
|
|
|
|
if(tcp_segment_key_chunk){
|
|
g_mem_chunk_destroy(tcp_segment_key_chunk);
|
|
tcp_segment_key_chunk = NULL;
|
|
}
|
|
if(tcp_segment_address_chunk){
|
|
g_mem_chunk_destroy(tcp_segment_address_chunk);
|
|
tcp_segment_address_chunk = NULL;
|
|
}
|
|
|
|
/* dont allocate any hash table or memory chunks unless the user
|
|
really uses this option
|
|
*/
|
|
if(!tcp_desegment){
|
|
return;
|
|
}
|
|
|
|
tcp_segment_table = g_hash_table_new(tcp_segment_hash,
|
|
tcp_segment_equal);
|
|
|
|
tcp_segment_key_chunk = g_mem_chunk_new("tcp_segment_key_chunk",
|
|
sizeof(tcp_segment_key),
|
|
tcp_segment_init_count*sizeof(tcp_segment_key),
|
|
G_ALLOC_ONLY);
|
|
|
|
tcp_segment_address_chunk = g_mem_chunk_new("tcp_segment_address_chunk",
|
|
sizeof(address),
|
|
tcp_segment_address_init_count*sizeof(address),
|
|
G_ALLOC_ONLY);
|
|
}
|
|
|
|
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 tcpinfo *tcpinfo = pinfo->private_data;
|
|
fragment_data *ipfd_head=NULL;
|
|
tcp_segment_key old_tsk, *tsk;
|
|
gboolean must_desegment = FALSE;
|
|
gboolean called_dissector = FALSE;
|
|
int deseg_offset;
|
|
guint32 deseg_seq;
|
|
gint nbytes;
|
|
proto_item *item;
|
|
|
|
/*
|
|
* 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;
|
|
|
|
/* First we must check if this TCP segment should be desegmented.
|
|
This is only to check if we should desegment this packet,
|
|
so we dont spend time doing COPY_ADDRESS/g_free.
|
|
We just "borrow" some address structures from pinfo instead. Cheaper.
|
|
*/
|
|
old_tsk.src = &pinfo->src;
|
|
old_tsk.dst = &pinfo->dst;
|
|
old_tsk.sport = sport;
|
|
old_tsk.dport = dport;
|
|
old_tsk.seq = seq;
|
|
tsk = g_hash_table_lookup(tcp_segment_table, &old_tsk);
|
|
|
|
if(tsk){
|
|
/* OK, this segment was found, which means it continues
|
|
a higher-level PDU. This means we must desegment it.
|
|
Add it to the defragmentation lists.
|
|
*/
|
|
ipfd_head = fragment_add(tvb, offset, pinfo, tsk->first_frame,
|
|
tcp_fragment_table,
|
|
seq - tsk->start_seq,
|
|
nxtseq - seq,
|
|
(LT_SEQ (nxtseq,tsk->start_seq + tsk->tot_len)) );
|
|
|
|
if(!ipfd_head){
|
|
/* fragment_add() returned NULL, This means that
|
|
desegmentation is not completed yet.
|
|
(its like defragmentation but we know we will
|
|
always add the segments in order).
|
|
XXX - no, we don't; there is no guarantee that
|
|
TCP segments are in order on the wire.
|
|
|
|
we must add next segment to our table so we will
|
|
find it later.
|
|
*/
|
|
tcp_segment_key *new_tsk;
|
|
|
|
new_tsk = g_mem_chunk_alloc(tcp_segment_key_chunk);
|
|
memcpy(new_tsk, tsk, sizeof(tcp_segment_key));
|
|
new_tsk->seq=nxtseq;
|
|
g_hash_table_insert(tcp_segment_table,new_tsk,new_tsk);
|
|
}
|
|
} 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);
|
|
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){
|
|
fragment_data *ipfd;
|
|
|
|
/*
|
|
* 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(GE_SEQ(nxtseq, tsk->start_seq + tsk->tot_len)){
|
|
/*
|
|
* 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, "Desegmented TCP");
|
|
|
|
/*
|
|
* Supply the sequence number of the first of the
|
|
* reassembled bytes.
|
|
*/
|
|
tcpinfo->seq = tsk->start_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);
|
|
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){
|
|
tcp_segment_key *new_tsk;
|
|
|
|
/*
|
|
* "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,tsk->first_frame,tcp_fragment_table);
|
|
tsk->tot_len = tvb_reported_length(next_tvb) + pinfo->desegment_len;
|
|
|
|
/*
|
|
* Update tsk structure.
|
|
* Can ask ->next->next because at least there's a hdr and one
|
|
* entry in fragment_add()
|
|
*/
|
|
for(ipfd=ipfd_head->next; ipfd->next; ipfd=ipfd->next){
|
|
old_tsk.seq = tsk->start_seq + ipfd->offset;
|
|
new_tsk = g_hash_table_lookup(tcp_segment_table, &old_tsk);
|
|
new_tsk->tot_len = tsk->tot_len;
|
|
}
|
|
|
|
/* this is the next segment in the sequence we want */
|
|
new_tsk = g_mem_chunk_alloc(tcp_segment_key_chunk);
|
|
memcpy(new_tsk, tsk, sizeof(tcp_segment_key));
|
|
new_tsk->seq = nxtseq;
|
|
g_hash_table_insert(tcp_segment_table,new_tsk,new_tsk);
|
|
} 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,
|
|
tcp_tree, pinfo, next_tvb);
|
|
|
|
/* 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) {
|
|
tcp_segment_key *tsk, *new_tsk;
|
|
|
|
/*
|
|
* 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);
|
|
|
|
/*
|
|
* XXX - how do we detect out-of-order transmissions?
|
|
* We can't just check for "nxtseq" being greater than
|
|
* "tsk->start_seq"; for now, we check for the difference
|
|
* being less than a megabyte, but this is a really
|
|
* gross hack - we really need to handle out-of-order
|
|
* transmissions correctly.
|
|
*/
|
|
if ((nxtseq - deseg_seq) <= 1024*1024) {
|
|
/* OK, subdissector wants us to desegment
|
|
some data before it can process it. Add
|
|
what remains of this packet and set
|
|
up next packet/sequence number as well.
|
|
|
|
We must remember this segment
|
|
*/
|
|
tsk = g_mem_chunk_alloc(tcp_segment_key_chunk);
|
|
tsk->src = g_mem_chunk_alloc(tcp_segment_address_chunk);
|
|
COPY_ADDRESS(tsk->src, &pinfo->src);
|
|
tsk->dst = g_mem_chunk_alloc(tcp_segment_address_chunk);
|
|
COPY_ADDRESS(tsk->dst, &pinfo->dst);
|
|
tsk->seq = deseg_seq;
|
|
tsk->start_seq = tsk->seq;
|
|
tsk->tot_len = nxtseq - tsk->start_seq + pinfo->desegment_len;
|
|
tsk->first_frame = pinfo->fd->num;
|
|
tsk->sport=sport;
|
|
tsk->dport=dport;
|
|
g_hash_table_insert(tcp_segment_table, tsk, tsk);
|
|
|
|
/* Add portion of segment unprocessed by the subdissector
|
|
to defragmentation lists */
|
|
fragment_add(tvb, deseg_offset, pinfo, tsk->first_frame,
|
|
tcp_fragment_table,
|
|
tsk->seq - tsk->start_seq,
|
|
nxtseq - tsk->start_seq,
|
|
LT_SEQ (nxtseq, tsk->start_seq + tsk->tot_len));
|
|
|
|
/* this is the next segment in the sequence we want */
|
|
new_tsk = g_mem_chunk_alloc(tcp_segment_key_chunk);
|
|
memcpy(new_tsk, tsk, sizeof(tcp_segment_key));
|
|
new_tsk->seq = nxtseq;
|
|
g_hash_table_insert(tcp_segment_table,new_tsk,new_tsk);
|
|
}
|
|
}
|
|
|
|
if (!called_dissector || pinfo->desegment_len != 0) {
|
|
if (ipfd_head != NULL && ipfd_head->reassembled_in != 0) {
|
|
/*
|
|
* 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, "[Desegmented TCP]");
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
/*
|
|
* 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),
|
|
void (*dissect_pdu)(tvbuff_t *, packet_info *, proto_tree *))
|
|
{
|
|
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;
|
|
|
|
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(pinfo, ws);
|
|
}
|
|
}
|
|
|
|
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;
|
|
guint leftedge, rightedge;
|
|
|
|
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);
|
|
proto_tree_add_uint_format(field_tree, hf_tcp_option_sack_sle, tvb,
|
|
offset, 4, leftedge,
|
|
"left edge = %u", leftedge);
|
|
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);
|
|
optlen -= 4;
|
|
proto_tree_add_uint_format(field_tree, hf_tcp_option_sack_sre, tvb,
|
|
offset+4, 4, rightedge,
|
|
"right edge = %u", rightedge);
|
|
tcp_info_append_uint(pinfo, "SLE", leftedge);
|
|
tcp_info_append_uint(pinfo, "SRE", 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;
|
|
|
|
gboolean
|
|
decode_tcp_ports(tvbuff_t *tvb, int offset, packet_info *pinfo,
|
|
proto_tree *tree, int src_port, int dst_port)
|
|
{
|
|
tvbuff_t *next_tvb;
|
|
int low_port, high_port;
|
|
|
|
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 */
|
|
if (dissector_try_heuristic(heur_subdissector_list, next_tvb, pinfo, tree)){
|
|
pinfo->want_pdu_tracking -= !!(pinfo->want_pdu_tracking);
|
|
return TRUE;
|
|
}
|
|
}
|
|
|
|
/* 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 */
|
|
if (dissector_try_heuristic(heur_subdissector_list, next_tvb, pinfo, tree)){
|
|
pinfo->want_pdu_tracking -= !!(pinfo->want_pdu_tracking);
|
|
return TRUE;
|
|
}
|
|
}
|
|
|
|
/* 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)
|
|
{
|
|
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);
|
|
}
|
|
}
|
|
}
|
|
/* 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) ){
|
|
/*
|
|
* 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);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
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.
|
|
*
|
|
* 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);
|
|
}
|
|
/*
|
|
* 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);
|
|
}
|
|
}
|
|
}
|
|
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)
|
|
{
|
|
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);
|
|
} 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);
|
|
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[64] = "<None>";
|
|
gchar *fstr[] = {"FIN", "SYN", "RST", "PSH", "ACK", "URG", "ECN", "CWR" };
|
|
gint fpos = 0, i;
|
|
guint bpos;
|
|
guint optlen;
|
|
guint32 nxtseq = 0;
|
|
guint reported_len;
|
|
vec_t cksum_vec[4];
|
|
guint32 phdr[2];
|
|
guint16 computed_cksum;
|
|
guint length_remaining;
|
|
gboolean desegment_ok;
|
|
struct tcpinfo tcpinfo;
|
|
static struct tcpheader tcphstruct[4], *tcph;
|
|
static int tcph_count=0;
|
|
|
|
tcph_count++;
|
|
if(tcph_count>=4){
|
|
tcph_count=0;
|
|
}
|
|
tcph=&tcphstruct[tcph_count];
|
|
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);
|
|
tcph->th_hlen = hi_nibble(th_off_x2) * 4; /* TCP header length, in bytes */
|
|
|
|
/*
|
|
* 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_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)");
|
|
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);
|
|
}
|
|
if(tcp_relative_seq){
|
|
tcp_get_relative_seq_ack(pinfo->fd->num, &(tcph->th_seq), &(tcph->th_ack), &(tcph->th_win));
|
|
}
|
|
}
|
|
|
|
/* 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) {
|
|
for (i = 0; i < 8; i++) {
|
|
bpos = 1 << i;
|
|
if (tcph->th_flags & bpos) {
|
|
if (fpos) {
|
|
strcpy(&flags[fpos], ", ");
|
|
fpos += 2;
|
|
}
|
|
strcpy(&flags[fpos], fstr[i]);
|
|
fpos += 3;
|
|
}
|
|
}
|
|
flags[fpos] = '\0';
|
|
}
|
|
|
|
if (check_col(pinfo->cinfo, COL_INFO)) {
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, " [%s] Seq=%u Ack=%u Win=%u",
|
|
flags, tcph->th_seq, tcph->th_ack, tcph->th_win);
|
|
}
|
|
|
|
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) {
|
|
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%04x (%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);
|
|
proto_tree_add_boolean(field_tree, hf_tcp_flags_reset, tvb, offset + 13, 1, tcph->th_flags);
|
|
proto_tree_add_boolean(field_tree, hf_tcp_flags_syn, tvb, offset + 13, 1, tcph->th_flags);
|
|
proto_tree_add_boolean(field_tree, hf_tcp_flags_fin, tvb, offset + 13, 1, tcph->th_flags);
|
|
proto_tree_add_uint(tcp_tree, hf_tcp_window_size, tvb, offset + 14, 2, tcph->th_win);
|
|
}
|
|
|
|
/* 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.... */
|
|
g_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 {
|
|
proto_tree_add_boolean_hidden(tcp_tree, hf_tcp_checksum_bad, tvb,
|
|
offset + 16, 2, TRUE);
|
|
proto_tree_add_uint_format(tcp_tree, hf_tcp_checksum, tvb,
|
|
offset + 16, 2, th_sum,
|
|
"Checksum: 0x%04x (incorrect, should be 0x%04x)", th_sum,
|
|
in_cksum_shouldbe(th_sum, computed_cksum));
|
|
|
|
if (check_col(pinfo->cinfo, COL_INFO))
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, " [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", 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", 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 */
|
|
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);
|
|
}
|
|
|
|
/* 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);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
}
|
|
}
|
|
|
|
/* 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);
|
|
}
|
|
tap_queue_packet(tcp_tap, pinfo, tcph);
|
|
}
|
|
|
|
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,
|
|
"", HFILL }},
|
|
|
|
{ &hf_tcp_checksum_bad,
|
|
{ "Bad Checksum", "tcp.checksum_bad", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
|
|
"", 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_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_violation,
|
|
{ "Zero Window Violation", "tcp.analysis.zero_window_violation", FT_NONE, BASE_NONE, NULL, 0x0,
|
|
"This is a zero-window violation, an attempt to write >1 byte to a zero-window", 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,
|
|
{ "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_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 desegmenting 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,
|
|
{ "Desegmentation error", "tcp.segment.error", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
|
|
"Desegmentation 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,
|
|
{ "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 starts but 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}},
|
|
};
|
|
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",
|
|
"Check the validity of the TCP checksum when possible",
|
|
"Whether to check the validity of the TCP checksum",
|
|
&tcp_check_checksum);
|
|
prefs_register_bool_preference(tcp_module, "desegment_tcp_streams",
|
|
"Allow subdissector to desegment TCP streams",
|
|
"Whether subdissector can request TCP streams to be desegmented",
|
|
&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_analyze_seq_init);
|
|
register_init_routine(tcp_desegment_init);
|
|
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");
|
|
}
|