forked from osmocom/wireshark
507 lines
15 KiB
C
507 lines
15 KiB
C
/* packet-tcp.c
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* Routines for TCP packet disassembly
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*
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* $Id: packet-tcp.c,v 1.24 1999/06/11 15:30:40 gram Exp $
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@zing.org>
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* Copyright 1998 Gerald Combs
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*
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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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#ifdef HAVE_SYS_TYPES_H
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# include <sys/types.h>
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#endif
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#ifdef HAVE_NETINET_IN_H
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# include <netinet/in.h>
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#endif
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#include <stdio.h>
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#include <glib.h>
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#include "packet.h"
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#include "resolv.h"
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#include "follow.h"
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#include "util.h"
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#ifdef NEED_SNPRINTF_H
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# ifdef HAVE_STDARG_H
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# include <stdarg.h>
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# else
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# include <varargs.h>
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# endif
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# include "snprintf.h"
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#endif
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#ifndef __PACKET_IP_H__
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#include "packet-ip.h"
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#endif
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extern FILE* data_out_file;
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extern packet_info pi;
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static gchar info_str[COL_MAX_LEN];
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static int info_len;
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/* TCP Ports */
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#define TCP_PORT_FTPDATA 20
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#define TCP_PORT_FTP 21
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#define TCP_PORT_TELNET 23
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#define TCP_PORT_SMTP 25
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#define TCP_PORT_HTTP 80
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#define TCP_PORT_POP 110
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#define TCP_PORT_NNTP 119
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#define TCP_PORT_NBSS 139
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#define TCP_PORT_PRINTER 515
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#define TCP_ALT_PORT_HTTP 8080
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#define TCP_PORT_PPTP 1723
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/* TCP structs and definitions */
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typedef struct _e_tcphdr {
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guint16 th_sport;
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guint16 th_dport;
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guint32 th_seq;
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guint32 th_ack;
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guint8 th_off_x2; /* combines th_off and th_x2 */
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guint8 th_flags;
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#define TH_FIN 0x01
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#define TH_SYN 0x02
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#define TH_RST 0x04
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#define TH_PUSH 0x08
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#define TH_ACK 0x10
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#define TH_URG 0x20
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guint16 th_win;
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guint16 th_sum;
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guint16 th_urp;
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} e_tcphdr;
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/*
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* TCP option
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*/
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#define TCPOPT_NOP 1 /* Padding */
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#define TCPOPT_EOL 0 /* End of options */
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#define TCPOPT_MSS 2 /* Segment size negotiating */
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#define TCPOPT_WINDOW 3 /* Window scaling */
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#define TCPOPT_SACK_PERM 4 /* SACK Permitted */
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#define TCPOPT_SACK 5 /* SACK Block */
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#define TCPOPT_ECHO 6
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#define TCPOPT_ECHOREPLY 7
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#define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
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#define TCPOPT_CC 11
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#define TCPOPT_CCNEW 12
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#define TCPOPT_CCECHO 13
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/*
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* TCP option lengths
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*/
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#define TCPOLEN_MSS 4
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#define TCPOLEN_WINDOW 3
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#define TCPOLEN_SACK_PERM 2
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#define TCPOLEN_SACK_MIN 2
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#define TCPOLEN_ECHO 6
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#define TCPOLEN_ECHOREPLY 6
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#define TCPOLEN_TIMESTAMP 10
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#define TCPOLEN_CC 6
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#define TCPOLEN_CCNEW 6
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#define TCPOLEN_CCECHO 6
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static void
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tcp_info_append_uint(const char *abbrev, guint32 val) {
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int add_len = 0;
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if (info_len > 0)
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if(info_len > 0)
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add_len = snprintf(&info_str[info_len], COL_MAX_LEN - info_len, " %s=%u",
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abbrev, val);
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if (add_len > 0)
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info_len += add_len;
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}
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static void
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dissect_tcpopt_maxseg(proto_tree *opt_tree, const char *name, const u_char *opd,
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int offset, guint optlen)
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{
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proto_tree_add_item(opt_tree, offset, optlen,
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"%s: %u bytes", name, pntohs(opd));
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tcp_info_append_uint("MSS", pntohs(opd));
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}
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static void
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dissect_tcpopt_wscale(proto_tree *opt_tree, const char *name, const u_char *opd,
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int offset, guint optlen)
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{
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proto_tree_add_item(opt_tree, offset, optlen,
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"%s: %u bytes", name, *opd);
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tcp_info_append_uint("WS", *opd);
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}
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static void
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dissect_tcpopt_sack(proto_tree *opt_tree, const char *name, const u_char *opd,
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int offset, guint optlen)
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{
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proto_tree *field_tree = NULL;
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proto_item *tf;
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guint leftedge, rightedge;
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tf = proto_tree_add_item(opt_tree, offset, optlen, "%s:", name);
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offset += 2; /* skip past type and length */
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optlen -= 2; /* subtract size of type and length */
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while (optlen > 0) {
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if (field_tree == NULL) {
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/* Haven't yet made a subtree out of this option. Do so. */
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field_tree = proto_tree_new();
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proto_item_add_subtree(tf, field_tree, ETT_TCP_OPTION_SACK);
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}
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if (optlen < 4) {
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proto_tree_add_item(field_tree, offset, optlen,
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"(suboption would go past end of option)");
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break;
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}
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/* XXX - check whether it goes past end of packet */
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leftedge = pntohl(opd);
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opd += 4;
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optlen -= 4;
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if (optlen < 4) {
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proto_tree_add_item(field_tree, offset, optlen,
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"(suboption would go past end of option)");
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break;
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}
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/* XXX - check whether it goes past end of packet */
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rightedge = pntohl(opd);
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opd += 4;
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optlen -= 4;
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proto_tree_add_item(field_tree, offset, 8,
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"left edge = %u, right edge = %u", leftedge, rightedge);
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tcp_info_append_uint("SLE", leftedge);
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tcp_info_append_uint("SRE", rightedge);
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offset += 8;
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}
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}
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static void
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dissect_tcpopt_echo(proto_tree *opt_tree, const char *name, const u_char *opd,
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int offset, guint optlen)
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{
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proto_tree_add_item(opt_tree, offset, optlen,
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"%s: %u", name, pntohl(opd));
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tcp_info_append_uint("ECHO", pntohl(opd));
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}
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static void
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dissect_tcpopt_timestamp(proto_tree *opt_tree, const char *name,
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const u_char *opd, int offset, guint optlen)
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{
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proto_tree_add_item(opt_tree, offset, optlen,
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"%s: tsval %u, tsecr %u", name, pntohl(opd), pntohl(opd + 4));
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tcp_info_append_uint("TSV", pntohl(opd));
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tcp_info_append_uint("TSER", pntohl(opd + 4));
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}
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static void
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dissect_tcpopt_cc(proto_tree *opt_tree, const char *name, const u_char *opd,
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int offset, guint optlen)
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{
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proto_tree_add_item(opt_tree, offset, optlen,
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"%s: %u", name, pntohl(opd));
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tcp_info_append_uint("CC", pntohl(opd));
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}
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static ip_tcp_opt tcpopts[] = {
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{
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TCPOPT_EOL,
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"EOL",
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NO_LENGTH,
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0,
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NULL,
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},
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{
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TCPOPT_NOP,
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"NOP",
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NO_LENGTH,
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0,
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NULL,
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},
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{
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TCPOPT_MSS,
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"Maximum segment size",
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FIXED_LENGTH,
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TCPOLEN_MSS,
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dissect_tcpopt_maxseg
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},
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{
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TCPOPT_WINDOW,
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"Window scale",
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FIXED_LENGTH,
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TCPOLEN_WINDOW,
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dissect_tcpopt_wscale
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},
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{
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TCPOPT_SACK_PERM,
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"SACK permitted",
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FIXED_LENGTH,
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TCPOLEN_SACK_PERM,
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NULL,
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},
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{
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TCPOPT_SACK,
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"SACK",
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VARIABLE_LENGTH,
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TCPOLEN_SACK_MIN,
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dissect_tcpopt_sack
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},
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{
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TCPOPT_ECHO,
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"Echo",
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FIXED_LENGTH,
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TCPOLEN_ECHO,
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dissect_tcpopt_echo
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},
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{
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TCPOPT_ECHOREPLY,
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"Echo reply",
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FIXED_LENGTH,
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TCPOLEN_ECHOREPLY,
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dissect_tcpopt_echo
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},
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{
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TCPOPT_TIMESTAMP,
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"Time stamp",
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FIXED_LENGTH,
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TCPOLEN_TIMESTAMP,
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dissect_tcpopt_timestamp
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},
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{
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TCPOPT_CC,
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"CC",
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FIXED_LENGTH,
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TCPOLEN_CC,
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dissect_tcpopt_cc
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},
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{
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TCPOPT_CCNEW,
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"CC.NEW",
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FIXED_LENGTH,
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TCPOPT_CCNEW,
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dissect_tcpopt_cc
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},
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{
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TCPOPT_CCECHO,
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"CC.ECHO",
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FIXED_LENGTH,
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TCPOLEN_CCECHO,
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dissect_tcpopt_cc
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}
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};
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#define N_TCP_OPTS (sizeof tcpopts / sizeof tcpopts[0])
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void
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dissect_tcp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
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e_tcphdr th;
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proto_tree *tcp_tree = NULL, *field_tree = NULL;
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proto_item *ti, *tf;
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gchar flags[64] = "<None>";
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gchar *fstr[] = {"FIN", "SYN", "RST", "PSH", "ACK", "URG"};
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gint fpos = 0, i;
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guint bpos;
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guint hlen;
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guint optlen;
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guint packet_max = pi.payload + offset;
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guint payload;
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/* To do: Check for {cap len,pkt len} < struct len */
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/* Avoids alignment problems on many architectures. */
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memcpy(&th, &pd[offset], sizeof(e_tcphdr));
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th.th_sport = ntohs(th.th_sport);
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th.th_dport = ntohs(th.th_dport);
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th.th_win = ntohs(th.th_win);
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th.th_sum = ntohs(th.th_sum);
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th.th_urp = ntohs(th.th_urp);
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th.th_seq = ntohl(th.th_seq);
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th.th_ack = ntohl(th.th_ack);
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info_len = 0;
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if (check_col(fd, COL_PROTOCOL) || tree) {
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for (i = 0; i < 6; i++) {
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bpos = 1 << i;
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if (th.th_flags & bpos) {
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if (fpos) {
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strcpy(&flags[fpos], ", ");
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fpos += 2;
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}
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strcpy(&flags[fpos], fstr[i]);
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fpos += 3;
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}
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}
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flags[fpos] = '\0';
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}
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hlen = hi_nibble(th.th_off_x2) * 4; /* TCP header length, in bytes */
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payload = pi.payload - hlen;
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if (check_col(fd, COL_RES_SRC_PORT))
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col_add_str(fd, COL_RES_SRC_PORT, get_tcp_port(th.th_sport));
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if (check_col(fd, COL_UNRES_SRC_PORT))
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col_add_fstr(fd, COL_UNRES_SRC_PORT, "%u", th.th_sport);
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if (check_col(fd, COL_RES_DST_PORT))
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col_add_str(fd, COL_RES_DST_PORT, get_tcp_port(th.th_dport));
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if (check_col(fd, COL_UNRES_DST_PORT))
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col_add_fstr(fd, COL_UNRES_DST_PORT, "%u", th.th_dport);
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if (check_col(fd, COL_PROTOCOL))
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col_add_str(fd, COL_PROTOCOL, "TCP");
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if (check_col(fd, COL_INFO)) {
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/* Copy the data into info_str in case one of the option handling
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routines needs to append to it. */
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if (th.th_flags & TH_URG)
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info_len = snprintf(info_str, COL_MAX_LEN, "%s > %s [%s] Seq=%u Ack=%u Win=%u Urg=%u",
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get_tcp_port(th.th_sport), get_tcp_port(th.th_dport), flags,
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th.th_seq, th.th_ack, th.th_win, th.th_urp);
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else
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info_len = snprintf(info_str, COL_MAX_LEN, "%s > %s [%s] Seq=%u Ack=%u Win=%u",
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get_tcp_port(th.th_sport), get_tcp_port(th.th_dport), flags,
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th.th_seq, th.th_ack, th.th_win);
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/* The info column is actually written after the options are decoded */
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}
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if (tree) {
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ti = proto_tree_add_item(tree, offset, hlen,
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"Transmission Control Protocol");
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tcp_tree = proto_tree_new();
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proto_item_add_subtree(ti, tcp_tree, ETT_TCP);
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proto_tree_add_item(tcp_tree, offset, 2, "Source port: %s (%u)",
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get_tcp_port(th.th_sport), th.th_sport);
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proto_tree_add_item(tcp_tree, offset + 2, 2, "Destination port: %s (%u)",
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get_tcp_port(th.th_dport), th.th_dport);
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proto_tree_add_item(tcp_tree, offset + 4, 4, "Sequence number: %u",
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th.th_seq);
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if (th.th_flags & TH_ACK)
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proto_tree_add_item(tcp_tree, offset + 8, 4, "Acknowledgement number: %u",
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th.th_ack);
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proto_tree_add_item(tcp_tree, offset + 12, 1, "Header length: %u bytes", hlen);
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tf = proto_tree_add_item(tcp_tree, offset + 13, 1, "Flags: 0x%x", th.th_flags);
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field_tree = proto_tree_new();
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proto_item_add_subtree(tf, field_tree, ETT_TCP_FLAGS);
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proto_tree_add_item(field_tree, offset + 13, 1, "%s",
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decode_boolean_bitfield(th.th_flags, TH_URG, sizeof (th.th_flags)*8,
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"Urgent pointer", "No urgent pointer"));
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proto_tree_add_item(field_tree, offset + 13, 1, "%s",
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decode_boolean_bitfield(th.th_flags, TH_ACK, sizeof (th.th_flags)*8,
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"Acknowledgment", "No acknowledgment"));
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proto_tree_add_item(field_tree, offset + 13, 1, "%s",
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decode_boolean_bitfield(th.th_flags, TH_PUSH, sizeof (th.th_flags)*8,
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"Push", "No push"));
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proto_tree_add_item(field_tree, offset + 13, 1, "%s",
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decode_boolean_bitfield(th.th_flags, TH_RST, sizeof (th.th_flags)*8,
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"Reset", "No reset"));
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proto_tree_add_item(field_tree, offset + 13, 1, "%s",
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decode_boolean_bitfield(th.th_flags, TH_SYN, sizeof (th.th_flags)*8,
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"Syn", "No Syn"));
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proto_tree_add_item(field_tree, offset + 13, 1, "%s",
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decode_boolean_bitfield(th.th_flags, TH_FIN, sizeof (th.th_flags)*8,
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"Fin", "No Fin"));
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proto_tree_add_item(tcp_tree, offset + 14, 2, "Window size: %u", th.th_win);
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proto_tree_add_item(tcp_tree, offset + 16, 2, "Checksum: 0x%04x", th.th_sum);
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if (th.th_flags & TH_URG)
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proto_tree_add_item(tcp_tree, offset + 18, 2, "Urgent pointer: 0x%04x",
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th.th_urp);
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}
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/* Decode TCP options, if any. */
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if (tree && hlen > sizeof (e_tcphdr)) {
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/* There's more than just the fixed-length header. Decode the
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options. */
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optlen = hlen - sizeof (e_tcphdr); /* length of options, in bytes */
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tf = proto_tree_add_item(tcp_tree, offset + 20, optlen,
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"Options: (%d bytes)", optlen);
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field_tree = proto_tree_new();
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proto_item_add_subtree(tf, field_tree, ETT_TCP_OPTIONS);
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dissect_ip_tcp_options(field_tree, &pd[offset + 20], offset + 20, optlen,
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tcpopts, N_TCP_OPTS, TCPOPT_EOL);
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}
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if (check_col(fd, COL_INFO))
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col_add_str(fd, COL_INFO, info_str);
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/* Skip over header + options */
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offset += hlen;
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pi.srcport = th.th_sport;
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pi.destport = th.th_dport;
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/* Check the packet length to see if there's more data
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(it could be an ACK-only packet) */
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if (packet_max > offset) {
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/* XXX - this should be handled the way UDP handles this, with a table
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of port numbers to which stuff can be added */
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#define PORT_IS(port) (th.th_sport == port || th.th_dport == port)
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if (PORT_IS(TCP_PORT_PRINTER))
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dissect_lpd(pd, offset, fd, tree);
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else if (PORT_IS(TCP_PORT_TELNET)) {
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pi.match_port = TCP_PORT_TELNET;
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dissect_telnet(pd, offset, fd, tree, payload);
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} else if (PORT_IS(TCP_PORT_FTPDATA)) {
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pi.match_port = TCP_PORT_FTPDATA;
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dissect_ftpdata(pd, offset, fd, tree, payload);
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} else if (PORT_IS(TCP_PORT_FTP)) {
|
|
pi.match_port = TCP_PORT_FTP;
|
|
dissect_ftp(pd, offset, fd, tree, payload);
|
|
} else if (PORT_IS(TCP_PORT_POP)) {
|
|
pi.match_port = TCP_PORT_POP;
|
|
dissect_pop(pd, offset, fd, tree, payload);
|
|
} else if (PORT_IS(TCP_PORT_NNTP)) {
|
|
pi.match_port = TCP_PORT_NNTP;
|
|
dissect_nntp(pd, offset, fd, tree, payload);
|
|
} else if (PORT_IS(TCP_PORT_PPTP)) {
|
|
pi.match_port = TCP_PORT_PPTP;
|
|
dissect_pptp(pd, offset, fd, tree);
|
|
} else if (PORT_IS(TCP_PORT_HTTP) || PORT_IS(TCP_ALT_PORT_HTTP))
|
|
dissect_http(pd, offset, fd, tree);
|
|
else if (PORT_IS(TCP_PORT_NBSS)) {
|
|
pi.match_port = TCP_PORT_NBSS;
|
|
dissect_nbss(pd, offset, fd, tree, payload);
|
|
} else {
|
|
/* check existence of high level protocols */
|
|
|
|
if (memcmp(&pd[offset], "GIOP", 4) == 0) {
|
|
dissect_giop(pd, offset, fd, tree);
|
|
}
|
|
else {
|
|
dissect_data(pd, offset, fd, tree);
|
|
}
|
|
}
|
|
}
|
|
|
|
if( data_out_file ) {
|
|
reassemble_tcp( th.th_seq, /* sequence number */
|
|
( pi.iplen -( pi.iphdrlen * 4 )-( hi_nibble(th.th_off_x2) * 4 ) ), /* length */
|
|
( pd+offset ), /* data */
|
|
( fd->cap_len - offset ), /* captured data length */
|
|
( th.th_flags & 0x02 ), /* is syn set? */
|
|
pi.ip_src ); /* src ip */
|
|
}
|
|
}
|