forked from osmocom/wireshark
448 lines
14 KiB
C
448 lines
14 KiB
C
/* packet-syslog.c
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* Routines for syslog message dissection
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*
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* Copyright 2000, Gerald Combs <gerald[AT]wireshark.org>
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*
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* Support for passing SS7 MSUs (from the Cisco ITP Packet Logging
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* facility) to the MTP3 dissector by Abhik Sarkar <sarkar.abhik[AT]gmail.com>
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* with some rework by Jeff Morriss <jeff.morriss.ws [AT] gmail.com>
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald[AT]wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "config.h"
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#include <epan/packet.h>
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#include <epan/strutil.h>
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#include "packet-syslog.h"
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#include "packet-acdr.h"
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#define UDP_PORT_SYSLOG 514
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#define PRIORITY_MASK 0x0007 /* 0000 0111 */
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#define FACILITY_MASK 0x03f8 /* 1111 1000 */
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void proto_reg_handoff_syslog(void);
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void proto_register_syslog(void);
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/* The maximum number if priority digits to read in. */
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#define MAX_DIGITS 3
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static const value_string short_level_vals[] = {
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{ LEVEL_EMERG, "EMERG" },
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{ LEVEL_ALERT, "ALERT" },
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{ LEVEL_CRIT, "CRIT" },
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{ LEVEL_ERR, "ERR" },
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{ LEVEL_WARNING, "WARNING" },
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{ LEVEL_NOTICE, "NOTICE" },
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{ LEVEL_INFO, "INFO" },
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{ LEVEL_DEBUG, "DEBUG" },
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{ 0, NULL }
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};
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static const value_string short_facility_vals[] = {
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{ FAC_KERN, "KERN" },
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{ FAC_USER, "USER" },
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{ FAC_MAIL, "MAIL" },
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{ FAC_DAEMON, "DAEMON" },
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{ FAC_AUTH, "AUTH" },
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{ FAC_SYSLOG, "SYSLOG" },
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{ FAC_LPR, "LPR" },
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{ FAC_NEWS, "NEWS" },
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{ FAC_UUCP, "UUCP" },
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{ FAC_CRON, "CRON" }, /* The BSDs, Linux, and others */
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{ FAC_AUTHPRIV, "AUTHPRIV" },
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{ FAC_FTP, "FTP" },
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{ FAC_NTP, "NTP" },
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{ FAC_LOGAUDIT, "LOGAUDIT" },
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{ FAC_LOGALERT, "LOGALERT" },
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{ FAC_CRON_SOL, "CRON" }, /* Solaris */
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{ FAC_LOCAL0, "LOCAL0" },
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{ FAC_LOCAL1, "LOCAL1" },
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{ FAC_LOCAL2, "LOCAL2" },
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{ FAC_LOCAL3, "LOCAL3" },
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{ FAC_LOCAL4, "LOCAL4" },
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{ FAC_LOCAL5, "LOCAL5" },
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{ FAC_LOCAL6, "LOCAL6" },
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{ FAC_LOCAL7, "LOCAL7" },
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{ 0, NULL }
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};
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static gint proto_syslog = -1;
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static gint hf_syslog_level = -1;
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static gint hf_syslog_facility = -1;
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static gint hf_syslog_msg = -1;
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static gint hf_syslog_msu_present = -1;
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static gint hf_syslog_version = -1;
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static gint hf_syslog_timestamp = -1;
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static gint hf_syslog_timestamp_old = -1;
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static gint hf_syslog_hostname = -1;
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static gint hf_syslog_appname = -1;
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static gint hf_syslog_procid = -1;
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static gint hf_syslog_msgid = -1;
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static gint hf_syslog_msgid_utf8 = -1;
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static gint hf_syslog_msgid_bom = -1;
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static gint ett_syslog = -1;
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static gint ett_syslog_msg = -1;
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static dissector_handle_t syslog_handle;
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static dissector_handle_t mtp_handle;
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/* The Cisco ITP's packet logging facility allows selected (SS7) MSUs to be
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* to be encapsulated in syslog UDP datagrams and sent to a monitoring tool.
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* However, no actual tool to monitor/decode the MSUs is provided. The aim
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* of this routine is to extract the hex dump of the MSU from the syslog
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* packet so that it can be passed on to the mtp3 dissector for decoding.
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*/
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static tvbuff_t *
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mtp3_msu_present(tvbuff_t *tvb, packet_info *pinfo, gint fac, gint level, const char *msg_str, gint chars_truncated)
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{
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size_t nbytes;
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size_t len;
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gchar **split_string, *msu_hex_dump;
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tvbuff_t *mtp3_tvb = NULL;
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guint8 *byte_array;
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/* In the sample capture I have, all MSUs are LOCAL0.DEBUG.
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* Try to optimize this routine for most syslog users by short-cutting
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* out here.
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*/
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if (!(fac == FAC_LOCAL0 && level == LEVEL_DEBUG))
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return NULL;
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if (strstr(msg_str, "msu=") == NULL)
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return NULL;
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split_string = g_strsplit(msg_str, "msu=", 2);
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msu_hex_dump = split_string[1];
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if (msu_hex_dump && (len = strlen(msu_hex_dump))) {
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/* convert_string_to_hex() will return NULL if it gets an incomplete
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* byte. If we have an odd string length then chop off the remaining
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* nibble so we can get at least a partial MSU (chances are the
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* subdissector will except out, of course).
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*/
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if (len % 2)
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msu_hex_dump[len - 1] = '\0';
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byte_array = convert_string_to_hex(msu_hex_dump, &nbytes);
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if (byte_array) {
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mtp3_tvb = tvb_new_child_real_data(tvb, byte_array, (guint)nbytes,
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(guint)nbytes + chars_truncated / 2);
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tvb_set_free_cb(mtp3_tvb, g_free);
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/* ...and add the encapsulated MSU as a new data source so that it gets
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* its own tab in the packet bytes pane.
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*/
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add_new_data_source(pinfo, mtp3_tvb, "Encapsulated MSU");
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}
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}
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g_strfreev(split_string);
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return(mtp3_tvb);
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}
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static gboolean dissect_syslog_info(proto_tree* tree, tvbuff_t* tvb, guint* offset, gint hfindex)
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{
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gint end_offset = tvb_find_guint8(tvb, *offset, -1, ' ');
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if (end_offset == -1)
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return FALSE;
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proto_tree_add_item(tree, hfindex, tvb, *offset, end_offset - *offset, ENC_NA);
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*offset = end_offset + 1;
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return TRUE;
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}
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/* Dissect message as defined in RFC5424 */
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static void
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dissect_syslog_message(proto_tree* tree, tvbuff_t* tvb, guint offset)
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{
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gint end_offset;
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if (!dissect_syslog_info(tree, tvb, &offset, hf_syslog_version))
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return;
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end_offset = tvb_find_guint8(tvb, offset, -1, ' ');
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if (end_offset == -1)
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return;
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if ((guint)end_offset != offset) {
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/* do not call proto_tree_add_time_item with a length of 0 */
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proto_tree_add_time_item(tree, hf_syslog_timestamp, tvb, offset, end_offset - offset, ENC_ISO_8601_DATE_TIME,
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NULL, NULL, NULL);
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}
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offset = end_offset + 1;
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if (!dissect_syslog_info(tree, tvb, &offset, hf_syslog_hostname))
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return;
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if (!dissect_syslog_info(tree, tvb, &offset, hf_syslog_appname))
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return;
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if (!dissect_syslog_info(tree, tvb, &offset, hf_syslog_procid))
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return;
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if (tvb_get_guint24(tvb, offset, ENC_BIG_ENDIAN) == 0xefbbbf) {
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proto_tree_add_item(tree, hf_syslog_msgid_bom, tvb, offset, 3, ENC_BIG_ENDIAN);
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offset += 3;
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proto_tree_add_item(tree, hf_syslog_msgid_utf8, tvb, offset, tvb_reported_length_remaining(tvb, offset), ENC_UTF_8|ENC_NA);
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} else {
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proto_tree_add_item(tree, hf_syslog_msgid, tvb, offset, tvb_reported_length_remaining(tvb, offset), ENC_ASCII|ENC_NA);
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}
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}
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/* Dissect message as defined in RFC3164 */
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static void
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dissect_rfc3164_syslog_message(proto_tree* tree, tvbuff_t* tvb, guint offset)
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{
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guint tvb_offset = 0;
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/* Simple check if the first 16 bytes look like TIMESTAMP "Mmm dd hh:mm:ss"
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* by checking for spaces and colons. Otherwise return without processing
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* the message. */
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if (tvb_get_guint8(tvb, offset + 3) == ' ' && tvb_get_guint8(tvb, offset + 6) == ' ' &&
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tvb_get_guint8(tvb, offset + 9) == ':' && tvb_get_guint8(tvb, offset + 12) == ':' &&
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tvb_get_guint8(tvb, offset + 15) == ' ') {
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proto_tree_add_item(tree, hf_syslog_timestamp_old, tvb, offset, 15, ENC_ASCII|ENC_NA);
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offset += 16;
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} else {
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return;
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}
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if (!dissect_syslog_info(tree, tvb, &offset, hf_syslog_hostname))
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return;
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for (tvb_offset=offset; tvb_offset < offset+32; tvb_offset++){
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guint8 octet;
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octet = tvb_get_guint8(tvb, tvb_offset);
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if (!g_ascii_isalnum(octet)){
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proto_tree_add_item(tree, hf_syslog_procid, tvb, offset, tvb_offset - offset, ENC_ASCII|ENC_NA);
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offset = tvb_offset;
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break;
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}
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}
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proto_tree_add_item(tree, hf_syslog_msgid, tvb, offset, tvb_reported_length_remaining(tvb, offset), ENC_ASCII|ENC_NA);
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}
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/* The message format is defined in RFC 3164 */
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static int
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dissect_syslog(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
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{
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gint pri = -1, lev = -1, fac = -1;
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gint msg_off = 0, msg_len, reported_msg_len;
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proto_item *ti;
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proto_tree *syslog_tree;
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proto_tree *syslog_message_tree;
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const char *msg_str;
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tvbuff_t *mtp3_tvb;
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "Syslog");
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col_clear(pinfo->cinfo, COL_INFO);
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if (tvb_get_guint8(tvb, msg_off) == '<') {
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/* A facility and level follow. */
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msg_off++;
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pri = 0;
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while (tvb_bytes_exist(tvb, msg_off, 1) &&
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g_ascii_isdigit(tvb_get_guint8(tvb, msg_off)) && msg_off <= MAX_DIGITS) {
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pri = pri * 10 + (tvb_get_guint8(tvb, msg_off) - '0');
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msg_off++;
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}
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if (tvb_get_guint8(tvb, msg_off) == '>')
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msg_off++;
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fac = (pri & FACILITY_MASK) >> 3;
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lev = pri & PRIORITY_MASK;
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}
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msg_len = tvb_ensure_captured_length_remaining(tvb, msg_off);
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msg_str = tvb_format_text(tvb, msg_off, msg_len);
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reported_msg_len = tvb_reported_length_remaining(tvb, msg_off);
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mtp3_tvb = mtp3_msu_present(tvb, pinfo, fac, lev, msg_str,
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(reported_msg_len - msg_len));
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if (mtp3_tvb == NULL) {
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if (pri >= 0) {
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col_add_fstr(pinfo->cinfo, COL_INFO, "%s.%s: %s",
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val_to_str_const(fac, short_facility_vals, "UNKNOWN"),
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val_to_str_const(lev, short_level_vals, "UNKNOWN"), msg_str);
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} else {
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col_add_str(pinfo->cinfo, COL_INFO, msg_str);
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}
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}
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if (tree) {
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if (pri >= 0) {
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ti = proto_tree_add_protocol_format(tree, proto_syslog, tvb, 0, -1,
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"Syslog message: %s.%s: %s",
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val_to_str_const(fac, short_facility_vals, "UNKNOWN"),
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val_to_str_const(lev, short_level_vals, "UNKNOWN"), msg_str);
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} else {
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ti = proto_tree_add_protocol_format(tree, proto_syslog, tvb, 0, -1,
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"Syslog message: (unknown): %s", msg_str);
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}
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syslog_tree = proto_item_add_subtree(ti, ett_syslog);
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if (pri >= 0) {
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proto_tree_add_uint(syslog_tree, hf_syslog_facility, tvb, 0,
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msg_off, pri);
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proto_tree_add_uint(syslog_tree, hf_syslog_level, tvb, 0,
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msg_off, pri);
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}
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ti = proto_tree_add_item(syslog_tree, hf_syslog_msg, tvb, msg_off,
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msg_len, ENC_UTF_8|ENC_NA);
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syslog_message_tree = proto_item_add_subtree(ti, ett_syslog_msg);
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/* RFC5424 defines a version field which is currently defined as '1'
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* followed by a space (0x3120). Otherwise the message is probable
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* a RFC3164 message.
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*/
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if (msg_len > 2 && tvb_get_ntohs(tvb, msg_off) == 0x3120) {
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dissect_syslog_message(syslog_message_tree, tvb, msg_off);
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} else if ( msg_len > 15) {
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dissect_rfc3164_syslog_message(syslog_message_tree, tvb, msg_off);
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}
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if (mtp3_tvb) {
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proto_item *mtp3_item;
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mtp3_item = proto_tree_add_boolean(syslog_tree, hf_syslog_msu_present,
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tvb, msg_off, msg_len, TRUE);
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proto_item_set_generated(mtp3_item);
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}
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}
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/* Call MTP dissector if encapsulated MSU was found... */
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if (mtp3_tvb) {
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call_dissector(mtp_handle, mtp3_tvb, pinfo, tree);
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}
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return tvb_captured_length(tvb);
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}
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/* Register the protocol with Wireshark */
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void proto_register_syslog(void)
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{
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/* Setup list of header fields */
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static hf_register_info hf[] = {
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{ &hf_syslog_facility,
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{ "Facility", "syslog.facility",
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FT_UINT8, BASE_DEC, VALS(syslog_facility_vals), FACILITY_MASK,
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"Message facility", HFILL }
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},
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{ &hf_syslog_level,
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{ "Level", "syslog.level",
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FT_UINT8, BASE_DEC, VALS(syslog_level_vals), PRIORITY_MASK,
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"Message level", HFILL }
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},
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{ &hf_syslog_msg,
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{ "Message", "syslog.msg",
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FT_STRING, BASE_NONE, NULL, 0x0,
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"Message Text", HFILL }
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},
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{ &hf_syslog_msu_present,
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{ "SS7 MSU present", "syslog.msu_present",
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FT_BOOLEAN, BASE_NONE, NULL, 0x0,
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"True if an SS7 MSU was detected in the syslog message",
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HFILL }
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},
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{ &hf_syslog_version,
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{ "Syslog version", "syslog.version",
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FT_STRING, BASE_NONE, NULL, 0x0,
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NULL,
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HFILL }
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},
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{ &hf_syslog_timestamp,
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{ "Syslog timestamp", "syslog.timestamp",
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FT_ABSOLUTE_TIME, ABSOLUTE_TIME_UTC, NULL, 0x0,
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NULL,
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HFILL }
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},
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{ &hf_syslog_timestamp_old,
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{ "Syslog timestamp (RFC3164)", "syslog.timestamp_rfc3164",
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FT_STRING, ENC_ASCII, NULL, 0x0,
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NULL,
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HFILL }
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},
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{ &hf_syslog_hostname,
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{ "Syslog hostname", "syslog.hostname",
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FT_STRING, ENC_ASCII, NULL, 0x0,
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NULL,
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HFILL }
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},
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{ &hf_syslog_appname,
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{ "Syslog app name", "syslog.appname",
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FT_STRING, ENC_ASCII, NULL, 0x0,
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"The name of the app that generated this message",
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HFILL }
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},
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{ &hf_syslog_procid,
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{ "Syslog process id", "syslog.procid",
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FT_STRING, ENC_ASCII, NULL, 0x0,
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NULL,
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HFILL }
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},
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{ &hf_syslog_msgid,
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{ "Syslog message id", "syslog.msgid",
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FT_STRING, ENC_ASCII, NULL, 0x0,
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NULL,
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HFILL }
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},
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{ &hf_syslog_msgid_utf8,
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{ "Syslog message id", "syslog.msgid",
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FT_STRING, STR_UNICODE, NULL, 0x0,
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NULL,
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HFILL }
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},
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{ &hf_syslog_msgid_bom,
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{ "Syslog BOM", "syslog.msgid.bom",
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FT_UINT24, BASE_HEX, NULL, 0x0,
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NULL,
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HFILL }
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}
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};
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/* Setup protocol subtree array */
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static gint *ett[] = {
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&ett_syslog,
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&ett_syslog_msg
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};
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/* Register the protocol name and description */
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proto_syslog = proto_register_protocol("Syslog message", "Syslog", "syslog");
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/* Required function calls to register the header fields and subtrees used */
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proto_register_field_array(proto_syslog, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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syslog_handle = register_dissector("syslog", dissect_syslog, proto_syslog);
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}
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void
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proto_reg_handoff_syslog(void)
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{
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dissector_add_uint_with_preference("udp.port", UDP_PORT_SYSLOG, syslog_handle);
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dissector_add_for_decode_as_with_preference("tcp.port", syslog_handle);
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dissector_add_uint("acdr.media_type", ACDR_Info, syslog_handle);
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/* Find the mtp3 dissector */
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mtp_handle = find_dissector_add_dependency("mtp3", proto_syslog);
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}
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/*
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* Editor modelines - https://www.wireshark.org/tools/modelines.html
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*
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* Local Variables:
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* c-basic-offset: 2
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
|
|
*
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|
* ex: set shiftwidth=2 tabstop=8 expandtab:
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|
* :indentSize=2:tabSize=8:noTabs=true:
|
|
*/
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