epan/plugins.c

   1 /* plugins.c
   2  * plugin routines
   3  *
   4  * $Id: plugins.c,v 1.53 2002/05/14 10:32:12 guy Exp $
   5  *
   6  * Ethereal - Network traffic analyzer
   7  * By Gerald Combs <gerald@ethereal.com>
   8  * Copyright 1999 Gerald Combs
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  23  */
  24
  25 #ifdef HAVE_CONFIG_H
  26 # include "config.h"
  27 #endif
  28
  29 #include "plugins.h"
  30
  31 #ifdef HAVE_PLUGINS
  32
  33 #include <time.h>
  34
  35 #ifdef HAVE_DIRENT_H
  36 #include <dirent.h>
  37 #endif
  38
  39 #ifdef HAVE_DIRECT_H
  40 #include <direct.h>
  41 #endif
  42
  43 #include <string.h>
  44 #include <stdlib.h>
  45 #include <errno.h>
  46
  47 #ifdef HAVE_SYS_STAT_H
  48 #include <sys/stat.h>
  49 #endif
  50
  51 #ifdef HAVE_SYS_TYPES_H
  52 #include <sys/types.h>
  53 #endif
  54
  55 #ifdef HAVE_UNISTD_H
  56 #include <unistd.h>
  57 #endif
  58
  59 #include "filesystem.h"
  60
  61 #include "prefs.h"
  62
  63 #ifdef PLUGINS_NEED_ADDRESS_TABLE
  64 #include "conversation.h"
  65 #include "packet-giop.h"
  66 #include "packet-tpkt.h"
  67 #include "packet-tcp.h"
  68 #include "plugins/plugin_table.h"
  69 static plugin_address_table_t   patable;
  70 #endif
  71
  72 /* linked list of all plugins */
  73 plugin *plugin_list;
  74
  75 #ifndef WIN32
  76 static gchar std_plug_dir[] = "/usr/lib/ethereal/plugins/" VERSION;
  77 static gchar local_plug_dir[] = "/usr/local/lib/ethereal/plugins/" VERSION;
  78 #endif
  79 static gchar *user_plug_dir = NULL;
  80
  81 #define PLUGINS_DIR_NAME        "plugins"
  82
  83 /*
  84  * add a new plugin to the list
  85  * returns :
  86  * - 0 : OK
  87  * - ENOMEM : memory allocation problem
  88  * - EEXIST : the same plugin (i.e. name/version) was already registered.
  89  */
  90 static int
  91 add_plugin(void *handle, gchar *name, gchar *version,
  92            void (*reg_handoff)(void))
  93 {
  94     plugin *new_plug, *pt_plug;
  95
  96     pt_plug = plugin_list;
  97     if (!pt_plug) /* the list is empty */
  98     {
  99         new_plug = (plugin *)g_malloc(sizeof(plugin));
 100         if (new_plug == NULL) return ENOMEM;
 101         plugin_list = new_plug;
 102     }
 103     else
 104     {
 105         while (1)
 106         {
 107             /* check if the same name/version is already registered */
 108             if (!strcmp(pt_plug->name, name) &&
 109                 !strcmp(pt_plug->version, version))
 110             {
 111                 return EEXIST;
 112             }
 113
 114             /* we found the last plugin in the list */
 115             if (pt_plug->next == NULL) break;
 116
 117             pt_plug = pt_plug->next;
 118         }
 119         new_plug = (plugin *)g_malloc(sizeof(plugin));
 120         if (new_plug == NULL) return ENOMEM;
 121         pt_plug->next = new_plug;
 122     }
 123
 124     new_plug->handle = handle;
 125     new_plug->name = name;
 126     new_plug->version = version;
 127     new_plug->reg_handoff = reg_handoff;
 128     new_plug->next = NULL;
 129     return 0;
 130 }
 131
 132 /*
 133  * XXX - when we remove support for old-style plugins (which we should
 134  * probably do eventually, as all plugins should be written as new-style
 135  * ones), we may want to have "init_plugins()" merely save a pointer
 136  * to the plugin's "init" routine, just as we save a pointer to its
 137  * "reg_handoff" routine, and have a "register_all_plugins()" routine
 138  * to go through the list of plugins and call all of them.
 139  *
 140  * Then we'd have "epan_init()", or perhaps even something higher up
 141  * in the call tree, call "init_plugins()", and have "proto_init()"
 142  * call "register_all_plugins()" right after calling "register_all_protocols()";
 143  * this might be a bit cleaner.
 144  */
 145 static void
 146 plugins_scan_dir(const char *dirname)
 147 {
 148 #define FILENAME_LEN    1024
 149     gchar         *hack_path;       /* pathname used to construct lt_lib_ext */
 150     gchar         *lt_lib_ext;      /* extension for loadable modules */
 151     DIR           *dir;             /* scanned directory */
 152     struct dirent *file;            /* current file */
 153     gchar          filename[FILENAME_LEN];   /* current file name */
 154     GModule       *handle;          /* handle returned by dlopen */
 155     gchar         *name;
 156     gchar         *version;
 157     void         (*init)(void *);
 158     void         (*reg_handoff)(void);
 159     gchar         *dot;
 160     int            cr;
 161
 162     /*
 163      * We find the extension used on this platform for loadable modules
 164      * by the sneaky hack of calling "g_module_build_path" to build
 165      * the pathname for a module with an empty directory name and
 166      * empty module name, and then search for the last "." and use
 167      * everything from the last "." on.
 168      *
 169      * GLib 2.0 will probably define G_MODULE_SUFFIX as the extension
 170      * to use, but that's not checked into the GLib CVS tree yet,
 171      * and we can't use it on systems that don't have GLib 2.0.
 172      */
 173     hack_path = g_module_build_path("", "");
 174     lt_lib_ext = strrchr(hack_path, '.');
 175     if (lt_lib_ext == NULL)
 176     {
 177         /*
 178          * Does this mean there *is* no extension?  Assume so.
 179          *
 180          * XXX - the code below assumes that all loadable modules have
 181          * an extension....
 182          */
 183         lt_lib_ext = "";
 184     }
 185
 186     if ((dir = opendir(dirname)) != NULL)
 187     {
 188         while ((file = readdir(dir)) != NULL)
 189         {
 190             /* don't try to open "." and ".." */
 191             if (!(strcmp(file->d_name, "..") &&
 192                   strcmp(file->d_name, "."))) continue;
 193
 194             /* skip anything but files with lt_lib_ext */
 195             dot = strrchr(file->d_name, '.');
 196             if (dot == NULL || strcmp(dot, lt_lib_ext) != 0) continue;
 197
 198             snprintf(filename, FILENAME_LEN, "%s" G_DIR_SEPARATOR_S "%s",
 199                 dirname, file->d_name);
 200             if ((handle = g_module_open(filename, 0)) == NULL)
 201             {
 202                 g_warning("Couldn't load module %s: %s", filename,
 203                           g_module_error());
 204                 continue;
 205             }
 206             name = (gchar *)file->d_name;
 207             if (g_module_symbol(handle, "version", (gpointer*)&version) == FALSE)
 208             {
 209                 g_warning("The plugin %s has no version symbol", name);
 210                 g_module_close(handle);
 211                 continue;
 212             }
 213
 214             /*
 215              * Old-style dissectors don't have a "plugin_reg_handoff()"
 216              * routine; we no longer support them.
 217              *
 218              * New-style dissectors have one, because, otherwise, there's
 219              * no way for them to arrange that they ever be called.
 220              */
 221             if (g_module_symbol(handle, "plugin_reg_handoff",
 222                                          (gpointer*)&reg_handoff))
 223             {
 224                 /*
 225                  * We require it to have a "plugin_init()" routine.
 226                  */
 227                 if (!g_module_symbol(handle, "plugin_init", (gpointer*)&init))
 228                 {
 229                     g_warning("The plugin %s has a plugin_reg_handoff symbol but no plugin_init routine",
 230                               name, filename);
 231                     g_module_close(handle);
 232                     continue;
 233                 }
 234
 235                 /*
 236                  * We have a "plugin_reg_handoff()" routine, so we don't
 237                  * need the protocol, filter string, or dissector pointer.
 238                  */
 239                 if ((cr = add_plugin(handle, g_strdup(file->d_name), version,
 240                                      reg_handoff)))
 241                 {
 242                     if (cr == EEXIST)
 243                         fprintf(stderr, "The plugin %s, version %s\n"
 244                             "was found in multiple directories\n", name, version);
 245                     else
 246                         fprintf(stderr, "Memory allocation problem\n"
 247                             "when processing plugin %s, version %s\n",
 248                             name, version);
 249                     g_module_close(handle);
 250                     continue;
 251                 }
 252
 253                 /*
 254                  * Call its init routine.
 255                  */
 256 #ifdef PLUGINS_NEED_ADDRESS_TABLE
 257                 init(&patable);
 258 #else
 259                 init(NULL);
 260 #endif
 261             }
 262             else
 263             {
 264                 /*
 265                  * This is an old-style dissector; warn that it won't
 266                  * be used, as those aren't supported.
 267                  */
 268                 fprintf(stderr,
 269                     "The plugin %s, version %s is an old-style plugin;\n"
 270                     "Those are no longer supported.\n", name, version);
 271             }
 272         }
 273         closedir(dir);
 274     }
 275     g_free(hack_path);
 276 }
 277
 278 /*
 279  * init plugins
 280  */
 281 void
 282 init_plugins(const char *plugin_dir)
 283 {
 284 #ifdef WIN32
 285     const char *datafile_dir;
 286     char *install_plugin_dir;
 287 #else
 288     struct stat std_dir_stat, local_dir_stat, plugin_dir_stat;
 289 #endif
 290
 291     if (plugin_list == NULL)      /* ensure init_plugins is only run once */
 292     {
 293 #ifdef PLUGINS_NEED_ADDRESS_TABLE
 294         /* Intialize address table */
 295         patable.p_check_col                     = check_col;
 296         patable.p_col_clear                     = col_clear;
 297         patable.p_col_add_fstr                  = col_add_fstr;
 298         patable.p_col_append_fstr               = col_append_fstr;
 299         patable.p_col_prepend_fstr              = col_prepend_fstr;
 300         patable.p_col_add_str                   = col_add_str;
 301         patable.p_col_append_str                = col_append_str;
 302         patable.p_col_set_str                   = col_set_str;
 303
 304         patable.p_register_init_routine         = register_init_routine;
 305         patable.p_register_postseq_cleanup_routine      = register_postseq_cleanup_routine;
 306
 307         patable.p_match_strval                  = match_strval;
 308         patable.p_val_to_str                    = val_to_str;
 309
 310         patable.p_conversation_new              = conversation_new;
 311         patable.p_find_conversation             = find_conversation;
 312         patable.p_conversation_set_dissector    = conversation_set_dissector;
 313
 314         patable.p_proto_register_protocol       = proto_register_protocol;
 315         patable.p_proto_register_field_array    = proto_register_field_array;
 316         patable.p_proto_register_subtree_array  = proto_register_subtree_array;
 317
 318         patable.p_dissector_add                 = dissector_add;
 319         patable.p_dissector_delete              = dissector_delete;
 320         patable.p_dissector_add_handle          = dissector_add_handle;
 321
 322         patable.p_heur_dissector_add            = heur_dissector_add;
 323
 324         patable.p_register_dissector            = register_dissector;
 325         patable.p_find_dissector                = find_dissector;
 326         patable.p_create_dissector_handle       = create_dissector_handle;
 327         patable.p_call_dissector                = call_dissector;
 328
 329         patable.p_tcp_dissect_pdus              = tcp_dissect_pdus;
 330
 331         patable.p_proto_is_protocol_enabled     = proto_is_protocol_enabled;
 332
 333         patable.p_proto_item_get_len            = proto_item_get_len;
 334         patable.p_proto_item_set_len            = proto_item_set_len;
 335         patable.p_proto_item_set_text           = proto_item_set_text;
 336         patable.p_proto_item_append_text        = proto_item_append_text;
 337         patable.p_proto_item_add_subtree        = proto_item_add_subtree;
 338         patable.p_proto_tree_add_item           = proto_tree_add_item;
 339         patable.p_proto_tree_add_item_hidden    = proto_tree_add_item_hidden;
 340         patable.p_proto_tree_add_protocol_format = proto_tree_add_protocol_format;
 341         patable.p_proto_tree_add_bytes          = proto_tree_add_bytes;
 342         patable.p_proto_tree_add_bytes_hidden   = proto_tree_add_bytes_hidden;
 343         patable.p_proto_tree_add_bytes_format   = proto_tree_add_bytes_format;
 344         patable.p_proto_tree_add_time           = proto_tree_add_time;
 345         patable.p_proto_tree_add_time_hidden    = proto_tree_add_time_hidden;
 346         patable.p_proto_tree_add_time_format    = proto_tree_add_time_format;
 347         patable.p_proto_tree_add_ipxnet         = proto_tree_add_ipxnet;
 348         patable.p_proto_tree_add_ipxnet_hidden  = proto_tree_add_ipxnet_hidden;
 349         patable.p_proto_tree_add_ipxnet_format  = proto_tree_add_ipxnet_format;
 350         patable.p_proto_tree_add_ipv4           = proto_tree_add_ipv4;
 351         patable.p_proto_tree_add_ipv4_hidden    = proto_tree_add_ipv4_hidden;
 352         patable.p_proto_tree_add_ipv4_format    = proto_tree_add_ipv4_format;
 353         patable.p_proto_tree_add_ipv6           = proto_tree_add_ipv6;
 354         patable.p_proto_tree_add_ipv6_hidden    = proto_tree_add_ipv6_hidden;
 355         patable.p_proto_tree_add_ipv6_format    = proto_tree_add_ipv6_format;
 356         patable.p_proto_tree_add_ether          = proto_tree_add_ether;
 357         patable.p_proto_tree_add_ether_hidden   = proto_tree_add_ether_hidden;
 358         patable.p_proto_tree_add_ether_format   = proto_tree_add_ether_format;
 359         patable.p_proto_tree_add_string         = proto_tree_add_string;
 360         patable.p_proto_tree_add_string_hidden  = proto_tree_add_string_hidden;
 361         patable.p_proto_tree_add_string_format  = proto_tree_add_string_format;
 362         patable.p_proto_tree_add_boolean        = proto_tree_add_boolean;
 363         patable.p_proto_tree_add_boolean_hidden = proto_tree_add_boolean_hidden;
 364         patable.p_proto_tree_add_boolean_format = proto_tree_add_boolean_format;
 365         patable.p_proto_tree_add_double         = proto_tree_add_double;
 366         patable.p_proto_tree_add_double_hidden  = proto_tree_add_double_hidden;
 367         patable.p_proto_tree_add_double_format  = proto_tree_add_double_format;
 368         patable.p_proto_tree_add_uint           = proto_tree_add_uint;
 369         patable.p_proto_tree_add_uint_hidden    = proto_tree_add_uint_hidden;
 370         patable.p_proto_tree_add_uint_format    = proto_tree_add_uint_format;
 371         patable.p_proto_tree_add_int            = proto_tree_add_int;
 372         patable.p_proto_tree_add_int_hidden     = proto_tree_add_int_hidden;
 373         patable.p_proto_tree_add_int_format     = proto_tree_add_int_format;
 374         patable.p_proto_tree_add_text           = proto_tree_add_text;
 375
 376         patable.p_tvb_new_subset                = tvb_new_subset;
 377         patable.p_tvb_set_free_cb               = tvb_set_free_cb;
 378         patable.p_tvb_set_child_real_data_tvbuff = tvb_set_child_real_data_tvbuff;
 379         patable.p_tvb_new_real_data             = tvb_new_real_data;
 380
 381         patable.p_tvb_length                    = tvb_length;
 382         patable.p_tvb_length_remaining          = tvb_length_remaining;
 383         patable.p_tvb_bytes_exist               = tvb_bytes_exist;
 384         patable.p_tvb_offset_exists             = tvb_offset_exists;
 385         patable.p_tvb_reported_length           = tvb_reported_length;
 386         patable.p_tvb_reported_length_remaining = tvb_reported_length_remaining;
 387
 388         patable.p_tvb_get_guint8                = tvb_get_guint8;
 389
 390         patable.p_tvb_get_ntohs                 = tvb_get_ntohs;
 391         patable.p_tvb_get_ntoh24                = tvb_get_ntoh24;
 392         patable.p_tvb_get_ntohl                 = tvb_get_ntohl;
 393
 394         patable.p_tvb_get_letohs                = tvb_get_letohs;
 395         patable.p_tvb_get_letoh24               = tvb_get_letoh24;
 396         patable.p_tvb_get_letohl                = tvb_get_letohl;
 397
 398         patable.p_tvb_memcpy                    = tvb_memcpy;
 399         patable.p_tvb_memdup                    = tvb_memdup;
 400
 401         patable.p_tvb_get_ptr                   = tvb_get_ptr;
 402
 403         patable.p_tvb_find_guint8               = tvb_find_guint8;
 404         patable.p_tvb_pbrk_guint8               = tvb_pbrk_guint8;
 405
 406         patable.p_tvb_strnlen                   = tvb_strnlen;
 407
 408         patable.p_tvb_format_text               = tvb_format_text;
 409
 410         patable.p_tvb_get_nstringz              = tvb_get_nstringz;
 411         patable.p_tvb_get_nstringz0             = tvb_get_nstringz0;
 412
 413         patable.p_tvb_find_line_end             = tvb_find_line_end;
 414         patable.p_tvb_find_line_end_unquoted    = tvb_find_line_end_unquoted;
 415
 416         patable.p_tvb_strneql                   = tvb_strneql;
 417         patable.p_tvb_strncaseeql               = tvb_strncaseeql;
 418
 419         patable.p_tvb_bytes_to_str              = tvb_bytes_to_str;
 420
 421         patable.p_prefs_register_protocol       = prefs_register_protocol;
 422         patable.p_prefs_register_uint_preference = prefs_register_uint_preference;
 423         patable.p_prefs_register_bool_preference = prefs_register_bool_preference;
 424         patable.p_prefs_register_enum_preference = prefs_register_enum_preference;
 425         patable.p_prefs_register_string_preference = prefs_register_string_preference;
 426
 427         patable.p_register_giop_user            = register_giop_user;
 428         patable.p_is_big_endian                 = is_big_endian;
 429         patable.p_get_CDR_encap_info            = get_CDR_encap_info;
 430
 431         patable.p_get_CDR_any                   = get_CDR_any;
 432         patable.p_get_CDR_boolean               = get_CDR_boolean;
 433         patable.p_get_CDR_char                  = get_CDR_char;
 434         patable.p_get_CDR_double                = get_CDR_double;
 435         patable.p_get_CDR_enum                  = get_CDR_enum;
 436         patable.p_get_CDR_fixed                 = get_CDR_fixed;
 437         patable.p_get_CDR_float                 = get_CDR_float;
 438         patable.p_get_CDR_interface             = get_CDR_interface;
 439         patable.p_get_CDR_long                  = get_CDR_long;
 440         patable.p_get_CDR_object                = get_CDR_object;
 441         patable.p_get_CDR_octet                 = get_CDR_octet;
 442         patable.p_get_CDR_octet_seq             = get_CDR_octet_seq;
 443         patable.p_get_CDR_short                 = get_CDR_short;
 444         patable.p_get_CDR_string                = get_CDR_string;
 445         patable.p_get_CDR_typeCode              = get_CDR_typeCode;
 446         patable.p_get_CDR_ulong                 = get_CDR_ulong;
 447         patable.p_get_CDR_ushort                = get_CDR_ushort;
 448         patable.p_get_CDR_wchar                 = get_CDR_wchar;
 449         patable.p_get_CDR_wstring               = get_CDR_wstring;
 450
 451         patable.p_is_tpkt                       = is_tpkt;
 452         patable.p_dissect_tpkt_encap            = dissect_tpkt_encap;
 453
 454         patable.p_set_actual_length             = set_actual_length;
 455         patable.p_decode_boolean_bitfield       = decode_boolean_bitfield;
 456         patable.p_decode_numeric_bitfield       = decode_numeric_bitfield;
 457         patable.p_decode_enumerated_bitfield    = decode_enumerated_bitfield;
 458 #endif
 459
 460 #ifdef WIN32
 461         /*
 462          * On Windows, the data file directory is the installation
 463          * directory; the plugins are stored under it.
 464          *
 465          * Assume we're running the installed version of Ethereal;
 466          * on Windows, the data file directory is the directory
 467          * in which the Ethereal binary resides.
 468          */
 469         datafile_dir = get_datafile_dir();
 470         install_plugin_dir = g_malloc(strlen(datafile_dir) + strlen("plugins") +
 471             strlen(VERSION) + 3);
 472         sprintf(install_plugin_dir, "%s\\plugins\\%s", datafile_dir, VERSION);
 473
 474         /*
 475          * Make sure that pathname refers to a directory.
 476          */
 477         if (test_for_directory(install_plugin_dir) != EISDIR) {
 478                 /*
 479                  * Either it doesn't refer to a directory or it
 480                  * refers to something that doesn't exist.
 481                  *
 482                  * Assume that means we're running, for example,
 483                  * a version of Ethereal we've built in a source
 484                  * directory, and fall back on the default
 485                  * installation directory, so you can put the plugins
 486                  * somewhere so they can be used with this version
 487                  * of Ethereal.
 488                  *
 489                  * XXX - should we, instead, have the Windows build
 490                  * procedure create a subdirectory of the "plugins"
 491                  * source directory, and copy the plugin DLLs there,
 492                  * so that you use the plugins from the build tree?
 493                  */
 494                 install_plugin_dir =
 495                     g_strdup("C:\\Program Files\\Ethereal\\plugins\\" VERSION);
 496         }
 497
 498         /*
 499          * Scan that directory.
 500          */
 501         plugins_scan_dir(install_plugin_dir);
 502         g_free(install_plugin_dir);
 503 #else
 504         /*
 505          * XXX - why not just scan "plugin_dir"?  That's where we
 506          * installed the plugins; if Ethereal isn't installed under
 507          * "/usr" or "/usr/local", why should we search for its plugins
 508          * there?
 509          */
 510         plugins_scan_dir(std_plug_dir);
 511         plugins_scan_dir(local_plug_dir);
 512         if ((strcmp(std_plug_dir, plugin_dir) != 0) &&
 513                 (strcmp(local_plug_dir, plugin_dir) != 0))
 514         {
 515             if (stat(plugin_dir, &plugin_dir_stat) == 0)
 516             {
 517                 /* check if plugin_dir is really different from std_dir and
 518                  * local_dir if they exist ! */
 519                 if (stat(std_plug_dir, &std_dir_stat) == 0)
 520                 {
 521                     if (stat(local_plug_dir, &local_dir_stat) == 0)
 522                     {
 523                         if ((plugin_dir_stat.st_dev != std_dir_stat.st_dev ||
 524                                     plugin_dir_stat.st_ino != std_dir_stat.st_ino) &&
 525                                 (plugin_dir_stat.st_dev != local_dir_stat.st_dev ||
 526                                  plugin_dir_stat.st_ino != local_dir_stat.st_ino))
 527                             plugins_scan_dir(plugin_dir);
 528                     }
 529                     else
 530                     {
 531                         if ((plugin_dir_stat.st_dev != std_dir_stat.st_dev ||
 532                                     plugin_dir_stat.st_ino != std_dir_stat.st_ino))
 533                             plugins_scan_dir(plugin_dir);
 534                     }
 535                 }
 536                 else if (stat(local_plug_dir, &local_dir_stat) == 0)
 537                 {
 538                     if ((plugin_dir_stat.st_dev != local_dir_stat.st_dev ||
 539                                 plugin_dir_stat.st_ino != local_dir_stat.st_ino))
 540                         plugins_scan_dir(plugin_dir);
 541                 }
 542                 else plugins_scan_dir(plugin_dir);
 543             }
 544         }
 545 #endif
 546         if (!user_plug_dir)
 547             user_plug_dir = get_persconffile_path(PLUGINS_DIR_NAME, FALSE);
 548         plugins_scan_dir(user_plug_dir);
 549     }
 550 }
 551
 552 void
 553 register_all_plugin_handoffs(void)
 554 {
 555   plugin *pt_plug;
 556
 557   /*
 558    * For all new-style plugins, call the register-handoff routine.
 559    * This is called from "proto_init()"; it must be called after
 560    * "register_all_protocols()" and "init_plugins()" are called,
 561    * in case one plugin registers itself either with a built-in
 562    * dissector or with another plugin; we must first register all
 563    * dissectors, whether built-in or plugin, so their dissector tables
 564    * are initialized, and only then register all handoffs.
 565    *
 566    * We treat those protocols as always being enabled; they should
 567    * use the standard mechanism for enabling/disabling protocols, not
 568    * the plugin-specific mechanism.
 569    */
 570   for (pt_plug = plugin_list; pt_plug != NULL; pt_plug = pt_plug->next)
 571     (pt_plug->reg_handoff)();
 572 }
 573 #endif