5500c09923
svn path=/trunk/; revision=3436
287 lines
8.6 KiB
C
287 lines
8.6 KiB
C
/* packet-udp.c
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* Routines for UDP packet disassembly
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*
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* $Id: packet-udp.c,v 1.92 2001/05/23 03:33:59 gerald Exp $
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@ethereal.com>
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* Copyright 1998 Gerald Combs
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*
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* Richard Sharpe, 13-Feb-1999, added dispatch table support and
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* support for tftp.
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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 <stdlib.h>
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#include <string.h>
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#include <glib.h>
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#include "globals.h"
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#include "resolv.h"
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#include "ipproto.h"
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#include "in_cksum.h"
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#include "prefs.h"
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#include "packet-udp.h"
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#include "packet-ip.h"
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#include "conversation.h"
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static int proto_udp = -1;
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static int hf_udp_srcport = -1;
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static int hf_udp_dstport = -1;
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static int hf_udp_port = -1;
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static int hf_udp_length = -1;
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static int hf_udp_checksum = -1;
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static int hf_udp_checksum_bad = -1;
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static gint ett_udp = -1;
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/* Place UDP summary in proto tree */
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static gboolean udp_summary_in_tree = TRUE;
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/* UDP structs and definitions */
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typedef struct _e_udphdr {
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guint16 uh_sport;
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guint16 uh_dport;
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guint16 uh_ulen;
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guint16 uh_sum;
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} e_udphdr;
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static dissector_table_t udp_dissector_table;
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static heur_dissector_list_t heur_subdissector_list;
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static conv_dissector_list_t conv_subdissector_list;
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/* Determine if there is a sub-dissector and call it. This has been */
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/* separated into a stand alone routine to other protocol dissectors */
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/* can call to it, ie. socks */
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void
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decode_udp_ports(tvbuff_t *tvb, int offset, packet_info *pinfo,
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proto_tree *tree, int uh_sport, int uh_dport)
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{
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tvbuff_t *next_tvb;
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next_tvb = tvb_new_subset(tvb, offset, -1, -1);
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/* determine if this packet is part of a conversation and call dissector */
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/* for the conversation if available */
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if (try_conversation_dissector(&pinfo->src, &pinfo->dst, PT_UDP,
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uh_sport, uh_dport, next_tvb, pinfo, tree))
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return;
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/* do lookup with the subdissector table */
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if (dissector_try_port(udp_dissector_table, uh_sport, next_tvb, pinfo, tree) ||
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dissector_try_port(udp_dissector_table, uh_dport, next_tvb, pinfo, tree))
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return;
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/* do lookup with the heuristic subdissector table */
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if (dissector_try_heuristic(heur_subdissector_list, next_tvb, pinfo, tree))
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return;
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dissect_data(next_tvb, 0, pinfo, tree);
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}
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static void
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dissect_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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e_udphdr uh;
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guint16 uh_sport, uh_dport, uh_ulen, uh_sum;
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proto_tree *udp_tree;
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proto_item *ti;
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guint len;
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guint reported_len;
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vec_t cksum_vec[4];
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guint32 phdr[2];
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guint16 computed_cksum;
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int offset = 0;
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if (check_col(pinfo->fd, COL_PROTOCOL))
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col_set_str(pinfo->fd, COL_PROTOCOL, "UDP");
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if (check_col(pinfo->fd, COL_INFO))
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col_clear(pinfo->fd, COL_INFO);
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/* Avoids alignment problems on many architectures. */
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tvb_memcpy(tvb, (guint8 *)&uh, offset, sizeof(e_udphdr));
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uh_sport = ntohs(uh.uh_sport);
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uh_dport = ntohs(uh.uh_dport);
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uh_ulen = ntohs(uh.uh_ulen);
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uh_sum = ntohs(uh.uh_sum);
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if (check_col(pinfo->fd, COL_INFO))
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col_add_fstr(pinfo->fd, COL_INFO, "Source port: %s Destination port: %s",
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get_udp_port(uh_sport), get_udp_port(uh_dport));
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if (tree) {
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if (udp_summary_in_tree) {
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ti = proto_tree_add_protocol_format(tree, proto_udp, tvb, offset, 8,
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"User Datagram Protocol, Src Port: %s (%u), Dst Port: %s (%u)",
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get_udp_port(uh_sport), uh_sport, get_udp_port(uh_dport), uh_dport);
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} else {
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ti = proto_tree_add_item(tree, proto_udp, tvb, offset, 8, FALSE);
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}
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udp_tree = proto_item_add_subtree(ti, ett_udp);
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proto_tree_add_uint_format(udp_tree, hf_udp_srcport, tvb, offset, 2, uh_sport,
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"Source port: %s (%u)", get_udp_port(uh_sport), uh_sport);
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proto_tree_add_uint_format(udp_tree, hf_udp_dstport, tvb, offset + 2, 2, uh_dport,
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"Destination port: %s (%u)", get_udp_port(uh_dport), uh_dport);
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proto_tree_add_uint_hidden(udp_tree, hf_udp_port, tvb, offset, 2, uh_sport);
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proto_tree_add_uint_hidden(udp_tree, hf_udp_port, tvb, offset+2, 2, uh_dport);
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proto_tree_add_uint(udp_tree, hf_udp_length, tvb, offset + 4, 2, uh_ulen);
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reported_len = tvb_reported_length(tvb);
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len = tvb_length(tvb);
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if (uh_sum == 0) {
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/* No checksum supplied in the packet. */
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proto_tree_add_uint_format(udp_tree, hf_udp_checksum, tvb,
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offset + 6, 2, uh_sum, "Checksum: 0x%04x (none)", uh_sum);
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} else if (!pinfo->fragmented && len >= reported_len) {
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/* The packet isn't part of a fragmented datagram and isn't
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truncated, so we can checksum it.
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XXX - make a bigger scatter-gather list once we do fragment
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reassembly? */
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/* Set up the fields of the pseudo-header. */
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cksum_vec[0].ptr = pinfo->src.data;
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cksum_vec[0].len = pinfo->src.len;
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cksum_vec[1].ptr = pinfo->dst.data;
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cksum_vec[1].len = pinfo->dst.len;
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cksum_vec[2].ptr = (const guint8 *)&phdr;
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switch (pinfo->src.type) {
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case AT_IPv4:
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phdr[0] = htonl((IP_PROTO_UDP<<16) + reported_len);
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cksum_vec[2].len = 4;
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break;
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case AT_IPv6:
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phdr[0] = htonl(reported_len);
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phdr[1] = htonl(IP_PROTO_UDP);
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cksum_vec[2].len = 8;
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break;
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default:
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/* TCP runs only atop IPv4 and IPv6.... */
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g_assert_not_reached();
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break;
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}
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cksum_vec[3].ptr = tvb_get_ptr(tvb, offset, len);
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cksum_vec[3].len = reported_len;
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computed_cksum = in_cksum(&cksum_vec[0], 4);
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if (computed_cksum == 0) {
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proto_tree_add_uint_format(udp_tree, hf_udp_checksum, tvb,
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offset + 6, 2, uh_sum, "Checksum: 0x%04x (correct)", uh_sum);
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} else {
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proto_tree_add_boolean_hidden(udp_tree, hf_udp_checksum_bad, tvb,
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offset + 6, 2, TRUE);
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proto_tree_add_uint_format(udp_tree, hf_udp_checksum, tvb,
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offset + 6, 2, uh_sum,
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"Checksum: 0x%04x (incorrect, should be 0x%04x)", uh_sum,
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in_cksum_shouldbe(uh_sum, computed_cksum));
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}
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} else {
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proto_tree_add_uint_format(udp_tree, hf_udp_checksum, tvb,
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offset + 6, 2, uh_sum, "Checksum: 0x%04x", uh_sum);
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}
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}
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/* Skip over header */
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offset += 8;
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pinfo->ptype = PT_UDP;
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pinfo->srcport = uh_sport;
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pinfo->destport = uh_dport;
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/* call sub-dissectors */
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decode_udp_ports( tvb, offset, pinfo, tree, uh_sport, uh_dport);
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}
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void
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proto_register_udp(void)
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{
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module_t *udp_module;
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static hf_register_info hf[] = {
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{ &hf_udp_srcport,
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{ "Source Port", "udp.srcport", FT_UINT16, BASE_DEC, NULL, 0x0,
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"" }},
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{ &hf_udp_dstport,
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{ "Destination Port", "udp.dstport", FT_UINT16, BASE_DEC, NULL, 0x0,
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"" }},
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{ &hf_udp_port,
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{ "Source or Destination Port", "udp.port", FT_UINT16, BASE_DEC, NULL, 0x0,
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"" }},
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{ &hf_udp_length,
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{ "Length", "udp.length", FT_UINT16, BASE_DEC, NULL, 0x0,
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"" }},
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{ &hf_udp_checksum_bad,
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{ "Bad Checksum", "udp.checksum_bad", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
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"" }},
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{ &hf_udp_checksum,
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{ "Checksum", "udp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
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"" }},
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};
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static gint *ett[] = {
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&ett_udp,
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};
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proto_udp = proto_register_protocol("User Datagram Protocol",
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"UDP", "udp");
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proto_register_field_array(proto_udp, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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/* subdissector code */
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udp_dissector_table = register_dissector_table("udp.port");
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register_heur_dissector_list("udp", &heur_subdissector_list);
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register_conv_dissector_list("udp", &conv_subdissector_list);
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/* Register configuration preferences */
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udp_module = prefs_register_protocol(proto_udp, NULL);
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prefs_register_bool_preference(udp_module, "udp_summary_in_tree",
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"Show UDP summary in protocol treee",
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"Whether the UDP summary line should be shown in the protocol tree",
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&udp_summary_in_tree);
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}
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void
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proto_reg_handoff_udp(void)
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{
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dissector_add("ip.proto", IP_PROTO_UDP, dissect_udp, proto_udp);
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}
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