epan/dissectors/packet-syslog.c

   1 /* packet-syslog.c
   2  * Routines for syslog message dissection
   3  *
   4  * Copyright 2000, Gerald Combs <gerald[AT]wireshark.org>
   5  *
   6  * Support for passing SS7 MSUs (from the Cisco ITP Packet Logging
   7  * facility) to the MTP3 dissector by Abhik Sarkar <sarkar.abhik[AT]gmail.com>
   8  * with some rework by Jeff Morriss <jeff.morriss.ws [AT] gmail.com>
   9  *
  10  * Wireshark - Network traffic analyzer
  11  * By Gerald Combs <gerald[AT]wireshark.org>
  12  * Copyright 1998 Gerald Combs
  13  *
  14  * SPDX-License-Identifier: GPL-2.0-or-later
  15  */
  16
  17 #include "config.h"
  18
  19 #include <epan/packet.h>
  20 #include <epan/expert.h>
  21 #include <epan/strutil.h>
  22
  23 #include "packet-syslog.h"
  24 #include "packet-acdr.h"
  25 #include "packet-tcp.h"
  26
  27 #define SYSLOG_PORT_UDP  514
  28 #define SYSLOG_PORT_TLS 6514
  29
  30 #define PRIORITY_MASK 0x0007  /* 0000 0111 */
  31 #define FACILITY_MASK 0x03F8  /* 1111 1000 */
  32
  33 #define MSG_BOM   0xEFBBBF
  34 #define RFC5424_V 0x3120      /* '1 ' */
  35 #define NIL_VALUE 0x2D        /* '-'  */
  36 #define SD_START  0x5B        /* '['  */
  37 #define SD_END    0x5D        /* ']'  */
  38 #define SD_STOP   0x5D20      /* '] ' */
  39 #define SD_DELIM  0x5D5B      /* '][' */
  40 #define CHR_SPACE 0x20        /* ' '  */
  41 #define CHR_COLON 0x3A        /* ':'  */
  42 #define CHR_EQUAL 0x3D        /* '='  */
  43 #define CHR_QUOTE 0x22        /* '"'  */
  44 #define CHR_0     0x30        /* '0'  */
  45
  46 void proto_reg_handoff_syslog(void);
  47 void proto_register_syslog(void);
  48
  49 /* The maximum number if priority digits to read in. */
  50 #define MAX_DIGITS 3
  51
  52 /* The maximum chars for framing to read in */
  53 #define MAX_FRAMING_DIGITS 5
  54
  55 static const value_string short_level_vals[] = {
  56   { LEVEL_EMERG,        "EMERG" },
  57   { LEVEL_ALERT,        "ALERT" },
  58   { LEVEL_CRIT,         "CRIT" },
  59   { LEVEL_ERR,          "ERR" },
  60   { LEVEL_WARNING,      "WARNING" },
  61   { LEVEL_NOTICE,       "NOTICE" },
  62   { LEVEL_INFO,         "INFO" },
  63   { LEVEL_DEBUG,        "DEBUG" },
  64   { 0, NULL }
  65 };
  66
  67 static const value_string short_facility_vals[] = {
  68   { FAC_KERN,           "KERN" },
  69   { FAC_USER,           "USER" },
  70   { FAC_MAIL,           "MAIL" },
  71   { FAC_DAEMON,         "DAEMON" },
  72   { FAC_AUTH,           "AUTH" },
  73   { FAC_SYSLOG,         "SYSLOG" },
  74   { FAC_LPR,            "LPR" },
  75   { FAC_NEWS,           "NEWS" },
  76   { FAC_UUCP,           "UUCP" },
  77   { FAC_CRON,           "CRON" },       /* The BSDs, Linux, and others */
  78   { FAC_AUTHPRIV,       "AUTHPRIV" },
  79   { FAC_FTP,            "FTP" },
  80   { FAC_NTP,            "NTP" },
  81   { FAC_LOGAUDIT,       "LOGAUDIT" },
  82   { FAC_LOGALERT,       "LOGALERT" },
  83   { FAC_CRON_SOL,       "CRON" },       /* Solaris */
  84   { FAC_LOCAL0,         "LOCAL0" },
  85   { FAC_LOCAL1,         "LOCAL1" },
  86   { FAC_LOCAL2,         "LOCAL2" },
  87   { FAC_LOCAL3,         "LOCAL3" },
  88   { FAC_LOCAL4,         "LOCAL4" },
  89   { FAC_LOCAL5,         "LOCAL5" },
  90   { FAC_LOCAL6,         "LOCAL6" },
  91   { FAC_LOCAL7,         "LOCAL7" },
  92   { 0, NULL }
  93 };
  94
  95 static int proto_syslog;
  96 static int hf_syslog_msglen;
  97 static int hf_syslog_level;
  98 static int hf_syslog_facility;
  99 static int hf_syslog_msu_present;
 100 static int hf_syslog_version;
 101 static int hf_syslog_timestamp;
 102 static int hf_syslog_timestamp_old;
 103 static int hf_syslog_hostname;
 104 static int hf_syslog_appname;
 105 static int hf_syslog_procid;
 106 static int hf_syslog_msg;
 107 static int hf_syslog_msgid;
 108 static int hf_syslog_bom;
 109 static int hf_syslog_sd;
 110 static int hf_syslog_sd_element;
 111 static int hf_syslog_sd_element_name;
 112 static int hf_syslog_sd_param;
 113 static int hf_syslog_sd_param_name;
 114 static int hf_syslog_sd_param_value;
 115
 116 static int ett_syslog;
 117 static int ett_syslog_sd;
 118 static int ett_syslog_sd_element;
 119 static int ett_syslog_sd_param;
 120
 121 static expert_field ei_syslog_msg_nonconformant;
 122
 123 static dissector_handle_t syslog_handle;
 124 static dissector_handle_t syslog_handle_tcp;
 125
 126 static dissector_handle_t mtp_handle;
 127
 128 /*  The Cisco ITP's packet logging facility allows selected (SS7) MSUs to be
 129  *  to be encapsulated in syslog UDP datagrams and sent to a monitoring tool.
 130  *  However, no actual tool to monitor/decode the MSUs is provided. The aim
 131  *  of this routine is to extract the hex dump of the MSU from the syslog
 132  *  packet so that it can be passed on to the mtp3 dissector for decoding.
 133  */
 134 static tvbuff_t *
 135 mtp3_msu_present(tvbuff_t *tvb, packet_info *pinfo, int fac, int level, const char *msg_str, int chars_truncated)
 136 {
 137   size_t nbytes;
 138   size_t len;
 139   char **split_string, *msu_hex_dump;
 140   tvbuff_t *mtp3_tvb = NULL;
 141   uint8_t *byte_array;
 142
 143   /*  In the sample capture I have, all MSUs are LOCAL0.DEBUG.
 144    *  Try to optimize this routine for most syslog users by short-cutting
 145    *  out here.
 146    */
 147   if (!(fac == FAC_LOCAL0 && level == LEVEL_DEBUG))
 148     return NULL;
 149
 150   if (strstr(msg_str, "msu=") == NULL)
 151     return NULL;
 152
 153   split_string = g_strsplit(msg_str, "msu=", 2);
 154   msu_hex_dump = split_string[1];
 155
 156   if (msu_hex_dump && (len = strlen(msu_hex_dump))) {
 157
 158     /*  convert_string_to_hex() will return NULL if it gets an incomplete
 159      *  byte.  If we have an odd string length then chop off the remaining
 160      *  nibble so we can get at least a partial MSU (chances are the
 161      *  subdissector will except out, of course).
 162      */
 163     if (len % 2)
 164         msu_hex_dump[len - 1] = '\0';
 165
 166     byte_array = convert_string_to_hex(msu_hex_dump, &nbytes);
 167
 168     if (byte_array) {
 169         mtp3_tvb = tvb_new_child_real_data(tvb, byte_array, (unsigned)nbytes,
 170                                            (unsigned)nbytes + chars_truncated / 2);
 171         tvb_set_free_cb(mtp3_tvb, g_free);
 172         /* ...and add the encapsulated MSU as a new data source so that it gets
 173          * its own tab in the packet bytes pane.
 174          */
 175         add_new_data_source(pinfo, mtp3_tvb, "Encapsulated MSU");
 176     }
 177   }
 178
 179   g_strfreev(split_string);
 180
 181   return mtp3_tvb;
 182 }
 183
 184 static bool dissect_syslog_info(proto_tree* tree, tvbuff_t* tvb, unsigned* offset, int hfindex)
 185 {
 186   int end_offset = tvb_find_uint8(tvb, *offset, -1, CHR_SPACE);
 187   if (end_offset == -1)
 188     return false;
 189   proto_tree_add_item(tree, hfindex, tvb, *offset, end_offset - *offset, ENC_NA);
 190   *offset = end_offset + 1;
 191   return true;
 192 }
 193
 194 static bool dissect_syslog_sd(proto_tree* tree, tvbuff_t* tvb, packet_info *pinfo, unsigned* offset)
 195 {
 196
 197   proto_item *ti;
 198   proto_tree *sd_tree;
 199   unsigned counter_parameters, counter_elements = 0;
 200
 201   // Check for NIL value
 202   if(tvb_reported_length_remaining(tvb, *offset) >= 2) {
 203     if(tvb_get_uint8(tvb, *offset) == NIL_VALUE && tvb_get_uint8(tvb, *offset + 1) == CHR_SPACE) {
 204       ti = proto_tree_add_item(tree, hf_syslog_sd, tvb, *offset, 1, ENC_NA);
 205       proto_item_append_text(ti, ": -");
 206       *offset = *offset + 2;
 207       return true;
 208     }
 209   }
 210
 211   /* Validate the start */
 212   if(tvb_get_uint8(tvb, *offset) != SD_START)
 213     return false;
 214
 215   /* Search the end */
 216   int sd_end = tvb_find_uint16(tvb, *offset, -1, SD_STOP);
 217   if (sd_end == -1)
 218     return false;
 219
 220   ti = proto_tree_add_item(tree, hf_syslog_sd, tvb, *offset, sd_end - *offset + 1, ENC_NA);
 221   sd_tree = proto_item_add_subtree(ti, ett_syslog_sd);
 222
 223   /* SD-ELEMENTS */
 224   while(*offset < (unsigned)sd_end) {
 225
 226     proto_item *ti_element;
 227     proto_tree *element_tree;
 228
 229     /* Find the end of current element (finding is guaranteed, because we already checked for SD_STOP) */
 230     int element_end = tvb_find_uint8(tvb, *offset, -1, SD_END);
 231     ti_element = proto_tree_add_item(sd_tree, hf_syslog_sd_element, tvb, *offset, element_end - *offset + 1, ENC_NA);
 232     element_tree = proto_item_add_subtree(ti_element, ett_syslog_sd_element);
 233
 234     /* First char is opening bracket, move offset */
 235     *offset = *offset + 1;
 236
 237     /* SD-ELEMENT */
 238     while(*offset < (unsigned)element_end) {
 239
 240       /* Find the first space char (=SD-NAME), move to next element if failed */
 241       int sdname_end = tvb_find_uint8(tvb, *offset, -1, CHR_SPACE);
 242       if(sdname_end == -1 || sdname_end >= element_end) {
 243         *offset = element_end + 1;
 244         break;
 245       }
 246
 247       proto_tree_add_item(element_tree, hf_syslog_sd_element_name, tvb, *offset, sdname_end - *offset, ENC_ASCII);
 248       proto_item_append_text(ti_element, " (%s)", tvb_get_string_enc(pinfo->pool, tvb, *offset, sdname_end - *offset, ENC_ASCII));
 249       *offset = sdname_end + 1;
 250
 251       /* PARAMETERS */
 252       counter_parameters = 0;
 253       while(*offset < (unsigned)element_end) {
 254
 255         proto_item *ti_param;
 256         proto_tree *param_tree;
 257
 258         /* Find the first equals char ('=') which delimits param name and value, move to next element if failed */
 259         int param_value_divide = tvb_find_uint8(tvb, *offset, -1, CHR_EQUAL);
 260         if(param_value_divide == -1 || param_value_divide >= element_end) {
 261           *offset = element_end + 1;
 262           break;
 263           break;
 264         }
 265
 266         /* Parameter Tree */
 267         ti_param = proto_tree_add_item(element_tree, hf_syslog_sd_param, tvb, *offset, 0, ENC_NA);
 268         param_tree = proto_item_add_subtree(ti_param, ett_syslog_sd_param);
 269
 270         /* Get parameter name */
 271         proto_tree_add_item(param_tree, hf_syslog_sd_param_name, tvb, *offset, param_value_divide - *offset, ENC_ASCII);
 272         proto_item_append_text(ti_param, " (%s)", tvb_get_string_enc(pinfo->pool, tvb, *offset, param_value_divide - *offset, ENC_ASCII));
 273         *offset = param_value_divide + 1;
 274
 275         /* Find the first and second quote char which marks the start and end of a value */
 276         int value_start = tvb_find_uint8(tvb, *offset,   -1, CHR_QUOTE);
 277         int value_end   = tvb_find_uint8(tvb, *offset+1, -1, CHR_QUOTE);
 278
 279         /* If start or end could not be determined, move to next element */
 280         if(value_start == -1 || value_end == -1 || value_start >= element_end || value_end >= element_end) {
 281           *offset = element_end + 1;
 282           break;
 283           break;
 284         }
 285
 286         proto_tree_add_item(param_tree, hf_syslog_sd_param_value, tvb, value_start+1, value_end-value_start-1, ENC_ASCII);
 287         proto_item_set_end(ti_param, tvb, value_end+1);
 288         *offset = value_end + 2;
 289
 290         counter_parameters++;
 291       }
 292
 293       proto_item_append_text(ti_element, " (%d parameter%s)", counter_parameters, plurality(counter_parameters, "", "s"));
 294       counter_elements++;
 295     }
 296   }
 297
 298   proto_item_append_text(ti, " (%d element%s)", counter_elements, plurality(counter_elements, "", "s"));
 299
 300   /* Move offset by one byte because space char is expected */
 301   *offset = *offset + 1;
 302   return true;
 303
 304 }
 305
 306 /* Dissect message as defined in RFC5424 */
 307 static unsigned
 308 dissect_rfc5424_syslog_message(proto_tree* tree, tvbuff_t* tvb, packet_info *pinfo, unsigned offset)
 309 {
 310   int end_offset;
 311
 312   if (!dissect_syslog_info(tree, tvb, &offset, hf_syslog_version))
 313     return offset;
 314
 315   end_offset = tvb_find_uint8(tvb, offset, -1, CHR_SPACE);
 316   if (end_offset == -1)
 317     return offset;
 318   if ((unsigned)end_offset != offset) {
 319     /* do not call proto_tree_add_time_item with a length of 0 */
 320     proto_tree_add_time_item(tree, hf_syslog_timestamp, tvb, offset, end_offset - offset, ENC_ISO_8601_DATE_TIME,
 321       NULL, NULL, NULL);
 322   }
 323   offset = end_offset + 1;
 324
 325   if (!dissect_syslog_info(tree, tvb, &offset, hf_syslog_hostname))
 326     return offset;
 327   if (!dissect_syslog_info(tree, tvb, &offset, hf_syslog_appname))
 328     return offset;
 329   if (!dissect_syslog_info(tree, tvb, &offset, hf_syslog_procid))
 330     return offset;
 331   if (!dissect_syslog_info(tree, tvb, &offset, hf_syslog_msgid))
 332     return offset;
 333
 334   /* STRUCTURED DATA */
 335   if (!dissect_syslog_sd(tree, tvb, pinfo, &offset))
 336     return offset;
 337
 338   /* Check for BOM and read in the rest of msg*/
 339   if (tvb_reported_length_remaining(tvb, offset) > 3 && tvb_get_uint24(tvb, offset, ENC_BIG_ENDIAN) == MSG_BOM) {
 340     proto_tree_add_item(tree, hf_syslog_bom, tvb, offset, 3, ENC_BIG_ENDIAN);
 341     offset += 3;
 342
 343     proto_tree_add_item(tree, hf_syslog_msg, tvb, offset, tvb_reported_length_remaining(tvb, offset), ENC_UTF_8);
 344   } else {
 345     proto_tree_add_item(tree, hf_syslog_msg, tvb, offset, tvb_reported_length_remaining(tvb, offset), ENC_ASCII);
 346   }
 347   return tvb_reported_length(tvb);
 348 }
 349
 350 /* Dissect message as defined in RFC3164 */
 351 static unsigned
 352 dissect_rfc3164_syslog_message(proto_tree* tree, tvbuff_t* tvb, unsigned offset)
 353 {
 354   unsigned tvb_offset = 0;
 355
 356   /* RFC 3164 HEADER section */
 357
 358   /* Simple check if the first 16 bytes look like TIMESTAMP "Mmm dd hh:mm:ss"
 359    * by checking for spaces and colons. Otherwise return without processing
 360    * the message. */
 361   if (tvb_get_uint8(tvb, offset + 3) == CHR_SPACE && tvb_get_uint8(tvb, offset + 6) == CHR_SPACE &&
 362         tvb_get_uint8(tvb, offset + 9) == CHR_COLON && tvb_get_uint8(tvb, offset + 12) == CHR_COLON &&
 363         tvb_get_uint8(tvb, offset + 15) == CHR_SPACE) {
 364     proto_tree_add_item(tree, hf_syslog_timestamp_old, tvb, offset, 15, ENC_ASCII);
 365     offset += 16;
 366   } else {
 367     return offset;
 368   }
 369
 370   if (!dissect_syslog_info(tree, tvb, &offset, hf_syslog_hostname))
 371     return offset;
 372
 373   /* RFC 3164 MSG section */
 374
 375   /* TAG field (proc) */
 376   for (tvb_offset=offset; tvb_offset < offset+32; tvb_offset++){
 377     uint8_t octet;
 378     octet = tvb_get_uint8(tvb, tvb_offset);
 379     if (!g_ascii_isalnum(octet)){
 380       proto_tree_add_item(tree, hf_syslog_procid, tvb, offset, tvb_offset - offset, ENC_ASCII);
 381       offset = tvb_offset+1;
 382       break;
 383     }
 384   }
 385
 386   /* CONTENT */
 387   /* Read in the rest as msg */
 388   proto_tree_add_item(tree, hf_syslog_msg, tvb, offset, tvb_reported_length_remaining(tvb, offset), ENC_ASCII);
 389   return tvb_reported_length(tvb);
 390 }
 391
 392 /* Checks if Octet Counting Framing is used and return entire PDU length */
 393 static unsigned
 394 get_framed_syslog_pdu_len(packet_info *pinfo, tvbuff_t *tvb, int offset, void *data _U_)
 395 {
 396   /*
 397     RFC 6587: Octet Counting Framing can be assumed if the data starts with non-zero digits.
 398     SYSLOG-FRAME = MSG-LEN SP SYSLOG-MSG
 399
 400     This function returns the length of the PDU (incl. leading <LEN><SPACE>)
 401   */
 402
 403   /* Find leading integers */
 404   int digits_str_len = 0;
 405   while(tvb_bytes_exist(tvb, offset + digits_str_len, 1) && digits_str_len < MAX_FRAMING_DIGITS) {
 406     uint8_t current_char = tvb_get_uint8(tvb, offset + digits_str_len);
 407     if(!g_ascii_isdigit(current_char) || (digits_str_len == 0 && current_char == CHR_0))
 408       break;
 409     digits_str_len++;
 410   }
 411
 412   /* Get the actual integer from string */
 413   unsigned msg_len = 0;
 414   unsigned multiplier = 1;
 415   if(digits_str_len > 0) {
 416     const uint8_t *digits_str = tvb_get_string_enc(pinfo->pool, tvb, offset, digits_str_len, ENC_ASCII);
 417     for (unsigned d = digits_str_len; d > 0; d--) {
 418       msg_len += ((digits_str[d-1] - CHR_0) * multiplier);
 419       multiplier *= 10;
 420     }
 421   }
 422
 423   /*
 424     When a <space> is found after the length digits, it seems to be framed TCP
 425   */
 426   if(msg_len > 0 && tvb_bytes_exist(tvb, offset, digits_str_len+1)) {
 427     if(tvb_get_uint8(tvb, offset + digits_str_len) == CHR_SPACE) {
 428       return msg_len + 1 + digits_str_len;
 429     }
 430   }
 431
 432   return 0;
 433
 434 }
 435
 436 /* Main dissection function */
 437 static int
 438 dissect_syslog(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
 439 {
 440   int pri = -1, lev = -1, fac = -1;
 441   int msg_off = 0, pri_digits = 0, pri_chars = 0, msg_len, reported_msg_len, framing_leading_str_len = 0;
 442   unsigned framing_pdu_len;
 443   proto_item *ti;
 444   proto_tree *syslog_tree;
 445   const char *msg_str;
 446   tvbuff_t *mtp3_tvb;
 447
 448   col_set_str(pinfo->cinfo, COL_PROTOCOL, "Syslog");
 449   col_clear(pinfo->cinfo, COL_INFO);
 450
 451   framing_pdu_len = get_framed_syslog_pdu_len(pinfo, tvb, msg_off, data);
 452   if(framing_pdu_len > 0) {
 453     framing_leading_str_len = snprintf(NULL, 0, "%d", framing_pdu_len) + 1;
 454     msg_off += framing_leading_str_len;
 455   }
 456
 457   if (tvb_get_uint8(tvb, msg_off) == '<') {
 458     /* A facility and level follow. */
 459     msg_off++;
 460     pri_chars++;
 461     pri = 0;
 462     while (tvb_bytes_exist(tvb, msg_off, 1) &&
 463            g_ascii_isdigit(tvb_get_uint8(tvb, msg_off)) && pri_digits <= MAX_DIGITS) {
 464       pri = pri * 10 + (tvb_get_uint8(tvb, msg_off) - CHR_0);
 465       pri_digits++;
 466       pri_chars++;
 467       msg_off++;
 468     }
 469     if (tvb_get_uint8(tvb, msg_off) == '>') {
 470       msg_off++;
 471       pri_chars++;
 472     }
 473     fac = (pri & FACILITY_MASK) >> 3;
 474     lev = pri & PRIORITY_MASK;
 475   }
 476
 477   msg_len = tvb_ensure_captured_length_remaining(tvb, msg_off);
 478   msg_str = tvb_format_text(pinfo->pool, tvb, msg_off, msg_len);
 479   reported_msg_len = tvb_reported_length_remaining(tvb, msg_off);
 480
 481   mtp3_tvb = mtp3_msu_present(tvb, pinfo, fac, lev, msg_str,
 482                               (reported_msg_len - msg_len));
 483
 484   if (mtp3_tvb == NULL) {
 485     if (pri >= 0) {
 486       col_add_fstr(pinfo->cinfo, COL_INFO, "%s.%s: %s",
 487         val_to_str_const(fac, short_facility_vals, "UNKNOWN"),
 488         val_to_str_const(lev, short_level_vals, "UNKNOWN"), msg_str);
 489     } else {
 490       col_add_str(pinfo->cinfo, COL_INFO, msg_str);
 491     }
 492   }
 493
 494   if (pri >= 0) {
 495     ti = proto_tree_add_protocol_format(tree, proto_syslog, tvb, 0, -1,
 496       "Syslog message: %s.%s: %s",
 497       val_to_str_const(fac, short_facility_vals, "UNKNOWN"),
 498       val_to_str_const(lev, short_level_vals, "UNKNOWN"), msg_str);
 499   } else {
 500     ti = proto_tree_add_protocol_format(tree, proto_syslog, tvb, 0, -1,
 501       "Syslog message: (unknown): %s", msg_str);
 502   }
 503   syslog_tree = proto_item_add_subtree(ti, ett_syslog);
 504
 505   if (framing_pdu_len)
 506     proto_tree_add_item(syslog_tree, hf_syslog_msglen, tvb, 0, framing_leading_str_len - 1, ENC_ASCII);
 507
 508   if (pri >= 0) {
 509     proto_tree_add_uint(syslog_tree, hf_syslog_facility, tvb, framing_leading_str_len,
 510       pri_chars, pri);
 511     proto_tree_add_uint(syslog_tree, hf_syslog_level, tvb, framing_leading_str_len,
 512       pri_chars, pri);
 513   }
 514
 515   /*
 516   *  RFC5424 defines a version field which is currently defined as '1'
 517   *  followed by a space (0x3120). Otherwise the message is probably
 518   *  a RFC3164 message.
 519   */
 520   unsigned offset = msg_off;
 521   if (msg_len > 2 && tvb_get_ntohs(tvb, msg_off) == RFC5424_V) {
 522     offset = dissect_rfc5424_syslog_message(syslog_tree, tvb, pinfo, msg_off);
 523   } else if ( msg_len > 15) {
 524     offset = dissect_rfc3164_syslog_message(syslog_tree, tvb, msg_off);
 525   }
 526   if (offset < tvb_reported_length(tvb)) {
 527     ti = proto_tree_add_item(syslog_tree, hf_syslog_msg, tvb, offset,
 528       tvb_reported_length_remaining(tvb, offset), ENC_ASCII);
 529     expert_add_info(pinfo, ti, &ei_syslog_msg_nonconformant);
 530   }
 531
 532   if (mtp3_tvb) {
 533     proto_item *mtp3_item;
 534     mtp3_item = proto_tree_add_boolean(syslog_tree, hf_syslog_msu_present,
 535                                         tvb, msg_off, msg_len, true);
 536     proto_item_set_generated(mtp3_item);
 537   }
 538
 539   /* Call MTP dissector if encapsulated MSU was found... */
 540   if (mtp3_tvb) {
 541     call_dissector(mtp_handle, mtp3_tvb, pinfo, tree);
 542   }
 543
 544   return tvb_captured_length(tvb);
 545 }
 546
 547 static int
 548 dissect_syslog_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
 549 {
 550
 551   /*
 552     When get_framed_syslog_pdu_len() returns >0, it has been checked for TCP Octet Counting Framing.
 553     It can be handed over to tcp_dissect_pdus().
 554   */
 555   if(get_framed_syslog_pdu_len(pinfo, tvb, 0, data) > 0) {
 556     tcp_dissect_pdus(tvb, pinfo, tree, true, MAX_FRAMING_DIGITS + 1, get_framed_syslog_pdu_len, dissect_syslog, data);
 557     return tvb_reported_length(tvb);
 558   }
 559
 560   /* If no framing was detected, simply pass it to the syslog dissector function */
 561   return dissect_syslog(tvb, pinfo, tree, data);
 562 }
 563
 564 /* Register the protocol with Wireshark */
 565 void proto_register_syslog(void)
 566 {
 567
 568   /* Setup list of header fields */
 569   static hf_register_info hf[] = {
 570     { &hf_syslog_msglen,
 571       { "Message Length", "syslog.msglen",
 572         FT_STRING, BASE_NONE, NULL, 0x0,
 573         "Length of message (without this field)", HFILL }
 574     },
 575     { &hf_syslog_facility,
 576       { "Facility", "syslog.facility",
 577         FT_UINT16, BASE_DEC, VALS(syslog_facility_vals), FACILITY_MASK,
 578         "Message facility", HFILL }
 579     },
 580     { &hf_syslog_level,
 581       { "Level", "syslog.level",
 582         FT_UINT16, BASE_DEC, VALS(syslog_level_vals), PRIORITY_MASK,
 583         "Message level", HFILL }
 584     },
 585     { &hf_syslog_msu_present,
 586       { "SS7 MSU present", "syslog.msu_present",
 587         FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 588         "True if an SS7 MSU was detected in the syslog message", HFILL }
 589     },
 590     { &hf_syslog_version,
 591       { "Version", "syslog.version",
 592         FT_STRING, BASE_NONE, NULL, 0x0,
 593         "Syslog version", HFILL }
 594     },
 595     { &hf_syslog_timestamp,
 596       { "Timestamp", "syslog.timestamp",
 597         FT_ABSOLUTE_TIME, ABSOLUTE_TIME_LOCAL, NULL, 0x0,
 598         NULL, HFILL }
 599     },
 600     { &hf_syslog_timestamp_old,
 601       { "Timestamp (RFC3164)", "syslog.timestamp_rfc3164",
 602         FT_STRING, BASE_NONE, NULL, 0x0,
 603         NULL, HFILL }
 604     },
 605     { &hf_syslog_hostname,
 606       { "Hostname", "syslog.hostname",
 607         FT_STRING, BASE_NONE, NULL, 0x0,
 608         "The hostname that generated this message", HFILL }
 609     },
 610     { &hf_syslog_appname,
 611       { "App Name", "syslog.appname",
 612         FT_STRING, BASE_NONE, NULL, 0x0,
 613         "The name of the app that generated this message", HFILL }
 614     },
 615     { &hf_syslog_procid,
 616       { "Process ID", "syslog.procid",
 617         FT_STRING, BASE_NONE, NULL, 0x0,
 618         "The ID of the process that generated this message", HFILL }
 619     },
 620     { &hf_syslog_msg,
 621       { "Message", "syslog.msg",
 622         FT_STRING, BASE_NONE, NULL, 0x0,
 623         NULL, HFILL }
 624     },
 625     { &hf_syslog_msgid,
 626       { "Message ID", "syslog.msgid",
 627         FT_STRING, BASE_NONE, NULL, 0x0,
 628         NULL, HFILL }
 629     },
 630     { &hf_syslog_bom,
 631       { "BOM", "syslog.msgid.bom",
 632         FT_UINT24, BASE_HEX, NULL, 0x0,
 633         "Byte Order Mark", HFILL }
 634     },
 635     { &hf_syslog_sd,
 636       { "Structured Data", "syslog.sd",
 637         FT_NONE, BASE_NONE, NULL, 0x0,
 638         NULL, HFILL }
 639     },
 640     { &hf_syslog_sd_element,
 641       { "Element", "syslog.sd.element",
 642         FT_NONE, BASE_NONE, NULL, 0x0,
 643         "Structured Data Element", HFILL }
 644     },
 645     { &hf_syslog_sd_element_name,
 646       { "Element Name", "syslog.sd.element.name",
 647         FT_STRING, BASE_NONE, NULL, 0x0,
 648         "Structured Data Element Name", HFILL }
 649     },
 650     { &hf_syslog_sd_param,
 651       { "Parameter", "syslog.sd.param",
 652         FT_NONE, BASE_NONE, NULL, 0x0,
 653         "Structured Data Parameter", HFILL }
 654     },
 655     { &hf_syslog_sd_param_name,
 656       { "Parameter Name", "syslog.sd.param.name",
 657         FT_STRING, BASE_NONE, NULL, 0x0,
 658         "Structured Data Parameter Name", HFILL }
 659     },
 660     { &hf_syslog_sd_param_value,
 661       { "Parameter Value", "syslog.sd.param.value",
 662         FT_STRING, BASE_NONE, NULL, 0x0,
 663         "Structured Data Parameter Value", HFILL }
 664     }
 665   };
 666
 667   /* Setup protocol subtree array */
 668   static int *ett[] = {
 669     &ett_syslog,
 670     &ett_syslog_sd,
 671     &ett_syslog_sd_element,
 672     &ett_syslog_sd_param
 673   };
 674
 675   static ei_register_info ei[] = {
 676     { &ei_syslog_msg_nonconformant, { "syslog.msg.nonconformant", PI_PROTOCOL, PI_NOTE, "Message conforms to neither RFC 5424 nor RFC 3164; trailing data appended", EXPFILL }}
 677   };
 678
 679   expert_module_t *expert_syslog;
 680
 681   /* Register the protocol name and description */
 682   proto_syslog = proto_register_protocol("Syslog Message", "Syslog", "syslog");
 683
 684   /* Required function calls to register the header fields and subtrees used */
 685   proto_register_field_array(proto_syslog, hf, array_length(hf));
 686   proto_register_subtree_array(ett, array_length(ett));
 687
 688   expert_syslog = expert_register_protocol(proto_syslog);
 689   expert_register_field_array(expert_syslog, ei, array_length(ei));
 690
 691   syslog_handle = register_dissector("syslog", dissect_syslog, proto_syslog);
 692   syslog_handle_tcp = register_dissector("syslog.tcp", dissect_syslog_tcp, proto_syslog);
 693 }
 694
 695 void
 696 proto_reg_handoff_syslog(void)
 697 {
 698   dissector_add_uint_with_preference("udp.port", SYSLOG_PORT_UDP, syslog_handle);
 699   dissector_add_for_decode_as_with_preference("tcp.port", syslog_handle_tcp);
 700   dissector_add_uint_with_preference("tls.port", SYSLOG_PORT_TLS, syslog_handle_tcp);
 701
 702   dissector_add_uint("acdr.media_type", ACDR_Info, syslog_handle);
 703
 704   /* Find the mtp3 dissector */
 705   mtp_handle = find_dissector_add_dependency("mtp3", proto_syslog);
 706 }
 707
 708 /*
 709  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 710  *
 711  * Local Variables:
 712  * c-basic-offset: 2
 713  * tab-width: 8
 714  * indent-tabs-mode: nil
 715  * End:
 716  *
 717  * ex: set shiftwidth=2 tabstop=8 expandtab:
 718  * :indentSize=2:tabSize=8:noTabs=true:
 719  */