extcap.c

   1 /* extcap.c
   2  *
   3  * Routines for extcap external capture
   4  * Copyright 2013, Mike Ryan <mikeryan@lacklustre.net>
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Gerald Combs <gerald@wireshark.org>
   8  * Copyright 1998 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  23  */
  24
  25 #include <config.h>
  26
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30
  31 #ifdef _WIN32
  32 #include <windows.h>
  33 #include <process.h>
  34 #include <time.h>
  35 #else
  36 /* Include for unlink */
  37 #include <unistd.h>
  38 #endif
  39
  40 #ifdef HAVE_SYS_TYPES_H
  41 #include <sys/types.h>
  42 #endif
  43 #ifdef HAVE_SYS_WAIT_H
  44 #include <sys/wait.h>
  45 #endif
  46
  47 #include <glib.h>
  48 #include <log.h>
  49
  50 #include <epan/prefs.h>
  51 #include <epan/prefs-int.h>
  52
  53 #include <wsutil/file_util.h>
  54 #include <wsutil/filesystem.h>
  55 #include <wsutil/tempfile.h>
  56
  57 #include "capture_opts.h"
  58
  59 #include "extcap.h"
  60 #include "extcap_parser.h"
  61 #include "extcap_spawn.h"
  62
  63 #ifdef _WIN32
  64 static HANDLE pipe_h = NULL;
  65 #endif
  66
  67 static void extcap_child_watch_cb(GPid pid, gint status, gpointer user_data);
  68
  69 /* internal container, for all the extcap interfaces that have been found.
  70  * will be resetted by every call to extcap_interface_list() and is being
  71  * used in extcap_get_if_* as well as extcap_init_interfaces to ensure,
  72  * that only extcap interfaces are being given to underlying extcap programs
  73  */
  74 static GHashTable *ifaces = NULL;
  75
  76 /* internal container, for all the extcap executables that have been found.
  77  * will be resetted by every call to extcap_interface_list() and is being
  78  * used for printing information about all extcap interfaces found
  79  */
  80 static GHashTable *tools = NULL;
  81
  82 /* internal container, to map preference names to pointers that hold preference
  83  * values. These ensure that preferences can survive extcap if garbage
  84  * collection, and does not lead to dangling pointers in the prefs subsystem.
  85  */
  86 static GHashTable *extcap_prefs_dynamic_vals = NULL;
  87
  88 /* Callback definition for extcap_foreach */
  89 typedef gboolean(*extcap_cb_t)(const gchar *extcap, const gchar *ifname, gchar *output, void *data,
  90                                gchar **err_str);
  91
  92 static gboolean
  93 extcap_if_exists(const gchar *ifname)
  94 {
  95     if (!ifname || !ifaces)
  96     {
  97         return FALSE;
  98     }
  99
 100     if (g_hash_table_lookup(ifaces, ifname))
 101     {
 102         return TRUE;
 103     }
 104
 105     return FALSE;
 106 }
 107
 108 static gboolean
 109 extcap_if_exists_for_extcap(const gchar *ifname, const gchar *extcap)
 110 {
 111     extcap_interface *entry = (extcap_interface *)g_hash_table_lookup(ifaces, ifname);
 112
 113     if (entry && strcmp(entry->extcap_path, extcap) == 0)
 114     {
 115         return TRUE;
 116     }
 117
 118     return FALSE;
 119 }
 120
 121 static gchar *
 122 extcap_if_executable(const gchar *ifname)
 123 {
 124     extcap_interface *interface = (extcap_interface *)g_hash_table_lookup(ifaces, ifname);
 125     return interface != NULL ? interface->extcap_path : NULL;
 126 }
 127
 128 static gboolean
 129 extcap_if_add(extcap_interface *interface)
 130 {
 131     if (g_hash_table_lookup(ifaces, interface->call))
 132     {
 133         return FALSE;
 134     }
 135
 136     g_hash_table_insert(ifaces, g_strdup(interface->call), interface);
 137     return TRUE;
 138 }
 139
 140 static void
 141 extcap_free_info(gpointer data)
 142 {
 143     extcap_info *info = (extcap_info *)data;
 144
 145     g_free(info->basename);
 146     g_free(info->full_path);
 147     g_free(info->version);
 148     g_free(info);
 149 }
 150
 151 static void
 152 extcap_tool_add(const gchar *extcap, const extcap_interface *interface)
 153 {
 154     char *toolname;
 155
 156     if (!extcap || !interface)
 157     {
 158         return;
 159     }
 160
 161     toolname = g_path_get_basename(extcap);
 162
 163     if (!g_hash_table_lookup(tools, toolname))
 164     {
 165         extcap_info *store = (extcap_info *)g_new0(extcap_info, 1);
 166         store->version = g_strdup(interface->version);
 167         store->full_path = g_strdup(extcap);
 168         store->basename = g_strdup(toolname);
 169
 170         g_hash_table_insert(tools, g_strdup(toolname), store);
 171     }
 172
 173     g_free(toolname);
 174 }
 175
 176 /* Note: args does not need to be NULL-terminated. */
 177 static void extcap_foreach(gint argc, gchar **args, extcap_cb_t cb,
 178                            void *cb_data, char **err_str, const char *ifname _U_)
 179 {
 180     const char *dirname = get_extcap_dir();
 181     GDir *dir;
 182     const gchar *file;
 183     gboolean keep_going;
 184
 185     keep_going = TRUE;
 186
 187     if ((dir = g_dir_open(dirname, 0, NULL)) != NULL)
 188     {
 189         GString *extcap_path = NULL;
 190
 191         extcap_path = g_string_new("");
 192         while (keep_going && (file = g_dir_read_name(dir)) != NULL)
 193         {
 194             gchar *command_output = NULL;
 195
 196             /* full path to extcap binary */
 197             g_string_printf(extcap_path, "%s" G_DIR_SEPARATOR_S "%s", dirname, file);
 198             if (extcap_if_exists(ifname) && !extcap_if_exists_for_extcap(ifname, extcap_path->str))
 199             {
 200                 continue;
 201             }
 202
 203             if (extcap_spawn_sync((gchar *) dirname, extcap_path->str, argc, args, &command_output))
 204             {
 205                 keep_going = cb(extcap_path->str, ifname, command_output, cb_data, err_str);
 206             }
 207
 208             g_free(command_output);
 209         }
 210
 211         g_dir_close(dir);
 212         g_string_free(extcap_path, TRUE);
 213     }
 214
 215 }
 216
 217 static void extcap_free_dlt(gpointer d, gpointer user_data _U_)
 218 {
 219     if (d == NULL)
 220     {
 221         return;
 222     }
 223
 224     g_free(((extcap_dlt *)d)->name);
 225     g_free(((extcap_dlt *)d)->display);
 226     g_free(d);
 227 }
 228
 229 static void extcap_free_dlts(GList *dlts)
 230 {
 231     g_list_foreach(dlts, extcap_free_dlt, NULL);
 232     g_list_free(dlts);
 233 }
 234
 235 static gboolean dlt_cb(const gchar *extcap _U_, const gchar *ifname _U_, gchar *output, void *data,
 236                        char **err_str)
 237 {
 238     GList *dlts = NULL, *temp = NULL;
 239
 240     if_capabilities_t *caps;
 241     GList *linktype_list = NULL;
 242     data_link_info_t *data_link_info;
 243     extcap_dlt *dlt_item;
 244
 245     dlts = extcap_parse_dlts(output);
 246     temp = dlts;
 247
 248     g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, "Extcap pipe %s ", extcap);
 249
 250     /*
 251      * Allocate the interface capabilities structure.
 252      */
 253     caps = (if_capabilities_t *) g_malloc(sizeof * caps);
 254     caps->can_set_rfmon = FALSE;
 255
 256     while (dlts)
 257     {
 258         dlt_item = (extcap_dlt *)dlts->data;
 259         if (dlt_item)
 260         {
 261             g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG,
 262                   "  DLT %d name=\"%s\" display=\"%s\" ", dlt_item->number,
 263                   dlt_item->name, dlt_item->display);
 264
 265             data_link_info = g_new(data_link_info_t, 1);
 266             data_link_info->dlt = dlt_item->number;
 267             data_link_info->name = g_strdup(dlt_item->name);
 268             data_link_info->description = g_strdup(dlt_item->display);
 269             linktype_list = g_list_append(linktype_list, data_link_info);
 270         }
 271
 272         dlts = g_list_next(dlts);
 273     }
 274
 275     /* Check to see if we built a list */
 276     if (linktype_list != NULL && data != NULL)
 277     {
 278         caps->data_link_types = linktype_list;
 279         *(if_capabilities_t **) data = caps;
 280     }
 281     else
 282     {
 283         if (err_str)
 284         {
 285             g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, "  returned no DLTs");
 286             *err_str = g_strdup("Extcap returned no DLTs");
 287         }
 288         g_free(caps);
 289     }
 290
 291     extcap_free_dlts(temp);
 292
 293     return FALSE;
 294 }
 295
 296 if_capabilities_t *
 297 extcap_get_if_dlts(const gchar *ifname, char **err_str)
 298 {
 299     gchar *argv[3];
 300     gint i;
 301     if_capabilities_t *caps = NULL;
 302
 303     if (err_str != NULL)
 304     {
 305         *err_str = NULL;
 306     }
 307
 308     if (extcap_if_exists(ifname))
 309     {
 310         argv[0] = g_strdup(EXTCAP_ARGUMENT_LIST_DLTS);
 311         argv[1] = g_strdup(EXTCAP_ARGUMENT_INTERFACE);
 312         argv[2] = g_strdup(ifname);
 313
 314         extcap_foreach(3, argv, dlt_cb, &caps, err_str, ifname);
 315
 316         for (i = 0; i < 3; ++i)
 317         {
 318             g_free(argv[i]);
 319         }
 320     }
 321
 322     return caps;
 323 }
 324
 325 static void extcap_free_interface(gpointer i)
 326 {
 327
 328     extcap_interface *interface = (extcap_interface *)i;
 329
 330     if (i == NULL)
 331     {
 332         return;
 333     }
 334
 335     g_free(interface->call);
 336     g_free(interface->display);
 337     g_free(interface->version);
 338     g_free(interface->help);
 339     g_free(interface->extcap_path);
 340     g_free(interface);
 341 }
 342
 343 static void extcap_free_interfaces(GList *interfaces)
 344 {
 345     if (interfaces == NULL)
 346     {
 347         return;
 348     }
 349
 350     g_list_foreach(interfaces, (GFunc)extcap_free_interface, NULL);
 351     g_list_free(interfaces);
 352 }
 353
 354 static gboolean interfaces_cb(const gchar *extcap, const gchar *ifname _U_, gchar *output, void *data,
 355                               char **err_str _U_)
 356 {
 357     GList **il = (GList **) data;
 358     GList *interfaces = NULL, *walker = NULL, *tmp = NULL;
 359     extcap_interface *int_iter = NULL;
 360     if_info_t *if_info = NULL;
 361
 362     interfaces = extcap_parse_interfaces(output);
 363
 364     g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, "Extcap pipe %s ", extcap);
 365
 366     walker = interfaces;
 367     char* help = NULL;
 368     while (walker != NULL)
 369     {
 370         /* Whether the interface information needs to be preserved or not. */
 371         gboolean preserve_interface = FALSE;
 372
 373         int_iter = (extcap_interface *)walker->data;
 374         if (int_iter->if_type == EXTCAP_SENTENCE_INTERFACE && extcap_if_exists(int_iter->call))
 375         {
 376             g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_WARNING, "Extcap interface \"%s\" is already provided by \"%s\" ",
 377                   int_iter->call, (gchar *)extcap_if_executable(int_iter->call));
 378             walker = g_list_next(walker);
 379             continue;
 380         }
 381
 382         if (int_iter->if_type == EXTCAP_SENTENCE_INTERFACE)
 383             g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, "  Interface [%s] \"%s\" ",
 384                   int_iter->call, int_iter->display);
 385         else if (int_iter->if_type == EXTCAP_SENTENCE_EXTCAP)
 386         {
 387             g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, "  Extcap [%s] ", int_iter->call);
 388             help = int_iter->help;
 389         }
 390
 391         if (int_iter->if_type == EXTCAP_SENTENCE_INTERFACE)
 392         {
 393             if (il != NULL)
 394             {
 395                 if_info = g_new0(if_info_t, 1);
 396                 if_info->name = g_strdup(int_iter->call);
 397                 if_info->friendly_name = g_strdup(int_iter->display);
 398
 399                 if_info->type = IF_EXTCAP;
 400
 401                 if_info->extcap = g_strdup(extcap);
 402                 *il = g_list_append(*il, if_info);
 403             }
 404
 405             int_iter->extcap_path = g_strdup(extcap);
 406             int_iter->help = g_strdup(help);
 407             preserve_interface = extcap_if_add(int_iter);
 408         }
 409
 410         /* Call for interfaces and tools alike. Multiple calls (because a tool has multiple
 411          * interfaces) are handled internally */
 412         extcap_tool_add(extcap, int_iter);
 413
 414         tmp = walker;
 415         walker = g_list_next(walker);
 416
 417         /* If interface was added to ifaces hash list then the hash list will free
 418          * the resources. Remove the interface from interfaces list so it won't be
 419          * freed when exiting this function */
 420         if (preserve_interface)
 421         {
 422             interfaces = g_list_delete_link(interfaces, tmp);
 423         }
 424     }
 425     extcap_free_interfaces(interfaces);
 426
 427     return TRUE;
 428 }
 429
 430 static gint
 431 if_info_compare(gconstpointer a, gconstpointer b)
 432 {
 433     gint comp = 0;
 434     const if_info_t *if_a = (const if_info_t *)a;
 435     const if_info_t *if_b = (const if_info_t *)b;
 436
 437     if ((comp = g_strcmp0(if_a->name, if_b->name)) == 0)
 438     {
 439         return g_strcmp0(if_a->friendly_name, if_b->friendly_name);
 440     }
 441
 442     return comp;
 443 }
 444
 445 static void
 446 extcap_reload_interface_list(GList **retp, char **err_str)
 447 {
 448     gchar *argv;
 449
 450     if (err_str != NULL)
 451     {
 452         *err_str = NULL;
 453     }
 454
 455     /* ifaces is used as cache, do not destroy its contents when
 456      * returning or no extcap interfaces can be queried for options */
 457     if (ifaces == NULL)
 458     {
 459         ifaces = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, extcap_free_interface);
 460     }
 461     else
 462     {
 463         g_hash_table_remove_all(ifaces);
 464     }
 465
 466     if (tools == NULL)
 467     {
 468         tools = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, extcap_free_info);
 469     }
 470     else
 471     {
 472         g_hash_table_remove_all(tools);
 473     }
 474
 475     argv = g_strdup(EXTCAP_ARGUMENT_LIST_INTERFACES);
 476
 477     extcap_foreach(1, &argv, interfaces_cb, retp, err_str, NULL);
 478
 479     g_free(argv);
 480 }
 481
 482 gchar *
 483 extcap_get_help_for_ifname(const char *ifname)
 484 {
 485     extcap_interface *interface = (extcap_interface *)g_hash_table_lookup(ifaces, ifname);
 486     return interface != NULL ? interface->help : NULL;
 487 }
 488
 489 GHashTable *
 490 extcap_tools_list(void)
 491 {
 492     if (tools == NULL || g_hash_table_size(tools) == 0)
 493     {
 494         extcap_reload_interface_list(NULL, NULL);
 495     }
 496
 497     return tools;
 498 }
 499
 500 GList *
 501 append_extcap_interface_list(GList *list, char **err_str)
 502 {
 503     GList *ret = NULL;
 504     GList *entry;
 505     void *data;
 506
 507     /* Update the extcap interfaces and get a list of their if_infos */
 508     extcap_reload_interface_list(&ret, err_str);
 509
 510     /* Sort that list */
 511     ret = g_list_sort(ret, if_info_compare);
 512
 513     /* Append the interfaces in that list to the list we're handed. */
 514     while (ret != NULL)
 515     {
 516         entry = g_list_first(ret);
 517         data = entry->data;
 518         ret = g_list_delete_link(ret, entry);
 519         list = g_list_append(list, data);
 520     }
 521     return list;
 522 }
 523
 524 static void
 525 extcap_register_preferences_callback(gpointer key, gpointer value _U_, gpointer user_data _U_)
 526 {
 527     GList *arguments;
 528
 529     arguments = extcap_get_if_configuration((gchar *)key);
 530     /* Memory for prefs are external to an interface, they are part of
 531      * extcap core, so the parsed arguments can be freed. */
 532     extcap_free_if_configuration(arguments, TRUE);
 533 }
 534
 535 void extcap_register_preferences(void)
 536 {
 537     module_t *dev_module = prefs_find_module("extcap");
 538
 539     if (!dev_module)
 540     {
 541         return;
 542     }
 543
 544     if (!ifaces || g_hash_table_size(ifaces) == 0)
 545     {
 546         extcap_reload_interface_list(NULL, NULL);
 547     }
 548
 549     g_hash_table_foreach(ifaces, extcap_register_preferences_callback, NULL);
 550 }
 551
 552 /**
 553  * Releases the dynamic preference value pointers. Must not be called before
 554  * prefs_cleanup since these pointers could still be in use.
 555  */
 556 void extcap_cleanup(void)
 557 {
 558     if (extcap_prefs_dynamic_vals)
 559     {
 560         g_hash_table_destroy(extcap_prefs_dynamic_vals);
 561     }
 562 }
 563
 564 void extcap_pref_store(extcap_arg *arg, const char *newval)
 565 {
 566     if (arg && arg->pref_valptr != NULL)
 567     {
 568         g_free(*arg->pref_valptr);
 569         *arg->pref_valptr = g_strdup(newval);
 570     }
 571
 572 }
 573
 574 /**
 575  * Obtains a pointer which can store a value for the given preference name.
 576  * The preference name that can be passed to the prefs API is stored into
 577  * 'prefs_name'.
 578  *
 579  * Extcap interfaces (and their preferences) are dynamic, they can be created
 580  * and destroyed at will. Thus their data structures are insufficient to pass to
 581  * the preferences APIs which require pointers which are valid until the
 582  * preferences are removed (at exit).
 583  */
 584 static gchar **extcap_prefs_dynamic_valptr(const char *name, char **pref_name)
 585 {
 586     gchar **valp;
 587     if (!extcap_prefs_dynamic_vals)
 588     {
 589         /* Initialize table only as needed, most preferences are not dynamic */
 590         extcap_prefs_dynamic_vals = g_hash_table_new_full(g_str_hash, g_str_equal,
 591                                     g_free, g_free);
 592     }
 593     if (!g_hash_table_lookup_extended(extcap_prefs_dynamic_vals, name,
 594                                       (gpointer *)pref_name, (gpointer *)&valp))
 595     {
 596         /* New dynamic pref, allocate, initialize and store. */
 597         valp = g_new0(gchar *, 1);
 598         *pref_name = g_strdup(name);
 599         g_hash_table_insert(extcap_prefs_dynamic_vals, *pref_name, valp);
 600     }
 601     return valp;
 602 }
 603
 604 void extcap_free_if_configuration(GList *list, gboolean free_args)
 605 {
 606     GList *elem, *sl;
 607
 608     for (elem = g_list_first(list); elem; elem = elem->next)
 609     {
 610         if (elem->data != NULL)
 611         {
 612             sl = g_list_first((GList *)elem->data);
 613             if (free_args)
 614             {
 615                 extcap_free_arg_list(sl);
 616             }
 617             else
 618             {
 619                 g_list_free(sl);
 620             }
 621         }
 622     }
 623     g_list_free(list);
 624 }
 625
 626 struct preference *
 627 extcap_pref_for_argument(const gchar *ifname, struct _extcap_arg *arg)
 628 {
 629     struct preference *pref = NULL;
 630
 631     GRegex *regex_name = g_regex_new("[-]+", (GRegexCompileFlags) 0, (GRegexMatchFlags) 0, NULL);
 632     GRegex *regex_ifname = g_regex_new("(?![a-zA-Z1-9_]).", (GRegexCompileFlags) 0, (GRegexMatchFlags) 0, NULL);
 633     if (regex_name && regex_ifname)
 634     {
 635         if (prefs_find_module("extcap"))
 636         {
 637             gchar *pref_name = g_regex_replace(regex_name, arg->call, strlen(arg->call), 0, "", (GRegexMatchFlags) 0, NULL);
 638             gchar *ifname_underscore = g_regex_replace(regex_ifname, ifname, strlen(ifname), 0, "_", (GRegexMatchFlags) 0, NULL);
 639             gchar *ifname_lowercase = g_ascii_strdown(ifname_underscore, -1);
 640             gchar *pref_ifname = g_strconcat(ifname_lowercase, ".", pref_name, NULL);
 641
 642             pref = prefs_find_preference(prefs_find_module("extcap"), pref_ifname);
 643
 644             g_free(pref_name);
 645             g_free(ifname_underscore);
 646             g_free(ifname_lowercase);
 647             g_free(pref_ifname);
 648         }
 649     }
 650     if (regex_name)
 651     {
 652         g_regex_unref(regex_name);
 653     }
 654     if (regex_ifname)
 655     {
 656         g_regex_unref(regex_ifname);
 657     }
 658
 659     return pref;
 660 }
 661
 662 static gboolean search_cb(const gchar *extcap _U_, const gchar *ifname _U_, gchar *output, void *data,
 663                           char **err_str _U_)
 664 {
 665     GList *arguments = NULL;
 666     GList **il = (GList **) data;
 667     module_t *dev_module = NULL;
 668
 669     arguments = extcap_parse_args(output);
 670
 671     dev_module = prefs_find_module("extcap");
 672
 673     if (dev_module)
 674     {
 675         GList *walker = arguments;
 676
 677         GRegex *regex_name = g_regex_new("[-]+", (GRegexCompileFlags) 0, (GRegexMatchFlags) 0, NULL);
 678         GRegex *regex_ifname = g_regex_new("(?![a-zA-Z1-9_]).", (GRegexCompileFlags) 0, (GRegexMatchFlags) 0, NULL);
 679         if (regex_name && regex_ifname)
 680         {
 681             while (walker != NULL)
 682             {
 683                 extcap_arg *arg = (extcap_arg *)walker->data;
 684                 arg->device_name = g_strdup(ifname);
 685
 686                 if (arg->save)
 687                 {
 688                     struct preference *pref = NULL;
 689
 690                     gchar *pref_name = g_regex_replace(regex_name, arg->call, strlen(arg->call), 0, "", (GRegexMatchFlags) 0, NULL);
 691                     gchar *ifname_underscore = g_regex_replace(regex_ifname, ifname, strlen(ifname), 0, "_", (GRegexMatchFlags) 0, NULL);
 692                     gchar *ifname_lowercase = g_ascii_strdown(ifname_underscore, -1);
 693                     gchar *pref_ifname = g_strconcat(ifname_lowercase, ".", pref_name, NULL);
 694
 695                     if ((pref = prefs_find_preference(dev_module, pref_ifname)) == NULL)
 696                     {
 697                         char *pref_name_for_prefs;
 698                         char *pref_title = wmem_strdup(wmem_epan_scope(), arg->display);
 699
 700                         arg->pref_valptr = extcap_prefs_dynamic_valptr(pref_ifname, &pref_name_for_prefs);
 701                         /* Set an initial value if any (the string will be copied at registration) */
 702                         if (arg->default_complex)
 703                         {
 704                             *arg->pref_valptr = arg->default_complex->_val;
 705                         }
 706
 707                         prefs_register_string_preference(dev_module, pref_name_for_prefs,
 708                                                          pref_title, pref_title, (const char **)arg->pref_valptr);
 709                     }
 710                     else
 711                     {
 712                         /* Been here before, restore stored value */
 713                         if (! arg->pref_valptr && pref->varp.string && strlen(*pref->varp.string))
 714                         {
 715                             arg->pref_valptr = pref->varp.string;
 716                         }
 717                     }
 718
 719                     g_free(pref_name);
 720                     g_free(ifname_underscore);
 721                     g_free(ifname_lowercase);
 722                     g_free(pref_ifname);
 723                 }
 724
 725                 walker = g_list_next(walker);
 726             }
 727         }
 728         if (regex_name)
 729         {
 730             g_regex_unref(regex_name);
 731         }
 732         if (regex_ifname)
 733         {
 734             g_regex_unref(regex_ifname);
 735         }
 736     }
 737
 738     *il = g_list_append(*il, arguments);
 739
 740     /* By returning false, extcap_foreach will break on first found */
 741     return TRUE;
 742 }
 743
 744 GList *
 745 extcap_get_if_configuration(const char *ifname)
 746 {
 747     gchar *argv[3];
 748     GList *ret = NULL;
 749     gchar **err_str = NULL;
 750     int i;
 751
 752     if (extcap_if_exists(ifname))
 753     {
 754         g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, "Extcap path %s",
 755               get_extcap_dir());
 756
 757         argv[0] = g_strdup(EXTCAP_ARGUMENT_CONFIG);
 758         argv[1] = g_strdup(EXTCAP_ARGUMENT_INTERFACE);
 759         argv[2] = g_strdup(ifname);
 760
 761         extcap_foreach(3, argv, search_cb, &ret, err_str, ifname);
 762
 763         for (i = 0; i < 3; i++)
 764         {
 765             g_free(argv[i]);
 766         }
 767     }
 768
 769     return ret;
 770 }
 771
 772 /**
 773  * If is_required is FALSE: returns TRUE if the extcap interface has
 774  * configurable options.
 775  * If is_required is TRUE: returns TRUE when the extcap interface has
 776  * configurable options that required modification. (For example, when an
 777  * argument is required but empty.)
 778  */
 779 gboolean
 780 extcap_has_configuration(const char *ifname, gboolean is_required)
 781 {
 782     GList *arguments = 0;
 783     GList *walker = 0, * item = 0;
 784
 785     gboolean found = FALSE;
 786
 787     arguments = extcap_get_if_configuration((const char *)(ifname));
 788     walker = g_list_first(arguments);
 789
 790     while (walker != NULL && !found)
 791     {
 792         item = g_list_first((GList *)(walker->data));
 793         while (item != NULL && !found)
 794         {
 795             if ((extcap_arg *)(item->data) != NULL)
 796             {
 797                 extcap_arg *arg = (extcap_arg *)(item->data);
 798                 /* Should required options be present, or any kind of options */
 799                 if (!is_required)
 800                 {
 801                     found = TRUE;
 802                 }
 803                 else if (arg->is_required)
 804                 {
 805                     const gchar *stored = NULL;
 806                     const gchar *defval = NULL;
 807
 808                     if (arg->pref_valptr != NULL)
 809                     {
 810                         stored = *arg->pref_valptr;
 811                     }
 812
 813                     if (arg->default_complex != NULL && arg->default_complex->_val != NULL)
 814                     {
 815                         defval = arg->default_complex->_val;
 816                     }
 817
 818                     if (arg->is_required)
 819                     {
 820                         /* If stored and defval is identical and the argument is required,
 821                          * configuration is needed */
 822                         if (defval && stored && g_strcmp0(stored, defval) == 0)
 823                         {
 824                             found = TRUE;
 825                         }
 826                         else if (!defval && (!stored || !*stored))
 827                         {
 828                             found = TRUE;
 829                         }
 830                     }
 831
 832                     if (arg->arg_type == EXTCAP_ARG_FILESELECT)
 833                     {
 834                         if (arg->fileexists && !(file_exists(defval) || file_exists(stored)))
 835                         {
 836                             found = TRUE;
 837                         }
 838                     }
 839                 }
 840             }
 841
 842             item = item->next;
 843         }
 844         walker = walker->next;
 845     }
 846     extcap_free_if_configuration(arguments, TRUE);
 847
 848     return found;
 849 }
 850
 851 /* taken from capchild/capture_sync.c */
 852 static gboolean pipe_data_available(int pipe_fd)
 853 {
 854 #ifdef _WIN32 /* PeekNamedPipe */
 855     HANDLE hPipe = (HANDLE) _get_osfhandle(pipe_fd);
 856     DWORD bytes_avail;
 857
 858     if (hPipe == INVALID_HANDLE_VALUE)
 859     {
 860         return FALSE;
 861     }
 862
 863     if (! PeekNamedPipe(hPipe, NULL, 0, NULL, &bytes_avail, NULL))
 864     {
 865         return FALSE;
 866     }
 867
 868     if (bytes_avail > 0)
 869     {
 870         return TRUE;
 871     }
 872     return FALSE;
 873 #else /* select */
 874     fd_set rfds;
 875     struct timeval timeout;
 876
 877     FD_ZERO(&rfds);
 878     FD_SET(pipe_fd, &rfds);
 879     timeout.tv_sec = 0;
 880     timeout.tv_usec = 0;
 881
 882     if (select(pipe_fd + 1, &rfds, NULL, NULL, &timeout) > 0)
 883     {
 884         return TRUE;
 885     }
 886
 887     return FALSE;
 888 #endif
 889 }
 890
 891 void extcap_if_cleanup(capture_options *capture_opts, gchar **errormsg)
 892 {
 893     interface_options interface_opts;
 894     extcap_userdata *userdata;
 895     guint icnt = 0;
 896     gboolean overwrite_exitcode;
 897     gchar *buffer;
 898 #define STDERR_BUFFER_SIZE 1024
 899
 900     for (icnt = 0; icnt < capture_opts->ifaces->len; icnt++)
 901     {
 902         interface_opts = g_array_index(capture_opts->ifaces, interface_options,
 903                                        icnt);
 904
 905         /* skip native interfaces */
 906         if (interface_opts.if_type != IF_EXTCAP)
 907         {
 908             continue;
 909         }
 910
 911         overwrite_exitcode = FALSE;
 912
 913         g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG,
 914               "Extcap [%s] - Cleaning up fifo: %s; PID: %d", interface_opts.name,
 915               interface_opts.extcap_fifo, interface_opts.extcap_pid);
 916 #ifdef _WIN32
 917         if (pipe_h)
 918         {
 919             g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG,
 920                   "Extcap [%s] - Closing pipe", interface_opts.name);
 921             FlushFileBuffers(pipe_h);
 922             DisconnectNamedPipe(pipe_h);
 923             CloseHandle(pipe_h);
 924         }
 925 #else
 926         if (interface_opts.extcap_fifo != NULL && file_exists(interface_opts.extcap_fifo))
 927         {
 928             /* the fifo will not be freed here, but with the other capture_opts in capture_sync */
 929             ws_unlink(interface_opts.extcap_fifo);
 930             interface_opts.extcap_fifo = NULL;
 931         }
 932 #endif
 933         /* Maybe the client closed and removed fifo, but ws should check if
 934          * pid should be closed */
 935         g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG,
 936               "Extcap [%s] - Closing spawned PID: %d", interface_opts.name,
 937               interface_opts.extcap_pid);
 938
 939         userdata = (extcap_userdata *) interface_opts.extcap_userdata;
 940         if (userdata)
 941         {
 942             if (userdata->extcap_stderr_rd > 0 && pipe_data_available(userdata->extcap_stderr_rd))
 943             {
 944                 buffer = (gchar *)g_malloc0(sizeof(gchar) * STDERR_BUFFER_SIZE + 1);
 945 #ifdef _WIN32
 946                 win32_readfrompipe((HANDLE)_get_osfhandle(userdata->extcap_stderr_rd), STDERR_BUFFER_SIZE, buffer);
 947 #else
 948                 if (read(userdata->extcap_stderr_rd, buffer, sizeof(gchar) * STDERR_BUFFER_SIZE) <= 0)
 949                 {
 950                     buffer[0] = '\0';
 951                 }
 952 #endif
 953                 if (strlen(buffer) > 0)
 954                 {
 955                     userdata->extcap_stderr = g_strdup_printf("%s", buffer);
 956                     userdata->exitcode = 1;
 957                 }
 958                 g_free(buffer);
 959             }
 960
 961 #ifndef _WIN32
 962             /* Final child watch may not have been called */
 963             if (interface_opts.extcap_child_watch != 0)
 964             {
 965                 extcap_child_watch_cb(userdata->pid, 0, capture_opts);
 966                 /* it will have changed in extcap_child_watch_cb */
 967                 interface_opts = g_array_index(capture_opts->ifaces, interface_options,
 968                                                icnt);
 969             }
 970 #endif
 971
 972             if (userdata->extcap_stderr != NULL)
 973             {
 974                 overwrite_exitcode = TRUE;
 975             }
 976
 977             if (overwrite_exitcode || userdata->exitcode != 0)
 978             {
 979                 if (userdata->extcap_stderr != 0)
 980                 {
 981                     if (*errormsg == NULL)
 982                     {
 983                         *errormsg = g_strdup_printf("Error by extcap pipe: %s", userdata->extcap_stderr);
 984                     }
 985                     else
 986                     {
 987                         gchar *temp = g_strconcat(*errormsg, "\nError by extcap pipe: " , userdata->extcap_stderr, NULL);
 988                         g_free(*errormsg);
 989                         *errormsg = temp;
 990                     }
 991                     g_free(userdata->extcap_stderr);
 992                 }
 993
 994                 userdata->extcap_stderr = NULL;
 995                 userdata->exitcode = 0;
 996             }
 997         }
 998
 999         if (interface_opts.extcap_child_watch > 0)
1000         {
1001             g_source_remove(interface_opts.extcap_child_watch);
1002             interface_opts.extcap_child_watch = 0;
1003         }
1004
1005         if (interface_opts.extcap_pid != INVALID_EXTCAP_PID)
1006         {
1007 #ifdef _WIN32
1008             TerminateProcess(interface_opts.extcap_pid, 0);
1009 #endif
1010             g_spawn_close_pid(interface_opts.extcap_pid);
1011             interface_opts.extcap_pid = INVALID_EXTCAP_PID;
1012
1013             g_free(interface_opts.extcap_userdata);
1014             interface_opts.extcap_userdata = NULL;
1015         }
1016
1017         /* Make sure modified interface_opts is saved in capture_opts. */
1018         capture_opts->ifaces = g_array_remove_index(capture_opts->ifaces, icnt);
1019         g_array_insert_val(capture_opts->ifaces, icnt, interface_opts);
1020     }
1021 }
1022
1023 static gboolean
1024 extcap_add_arg_and_remove_cb(gpointer key, gpointer value, gpointer data)
1025 {
1026     GPtrArray *args = (GPtrArray *)data;
1027
1028     if (key != NULL)
1029     {
1030         g_ptr_array_add(args, g_strdup((const gchar *)key));
1031
1032         if (value != NULL)
1033         {
1034             g_ptr_array_add(args, g_strdup((const gchar *)value));
1035         }
1036
1037         return TRUE;
1038     }
1039
1040     return FALSE;
1041 }
1042
1043 void extcap_child_watch_cb(GPid pid, gint status, gpointer user_data)
1044 {
1045     guint i;
1046     interface_options interface_opts;
1047     extcap_userdata *userdata = NULL;
1048     capture_options *capture_opts = (capture_options *)(user_data);
1049
1050     if (capture_opts == NULL || capture_opts->ifaces == NULL || capture_opts->ifaces->len == 0)
1051     {
1052         return;
1053     }
1054
1055     /* Close handle to child process. */
1056     g_spawn_close_pid(pid);
1057
1058     /* Update extcap_pid in interface options structure. */
1059     for (i = 0; i < capture_opts->ifaces->len; i++)
1060     {
1061         interface_opts = g_array_index(capture_opts->ifaces, interface_options, i);
1062         if (interface_opts.extcap_pid == pid)
1063         {
1064             userdata = (extcap_userdata *)interface_opts.extcap_userdata;
1065             if (userdata != NULL)
1066             {
1067                 interface_opts.extcap_pid = INVALID_EXTCAP_PID;
1068                 userdata->exitcode = 0;
1069 #ifndef _WIN32
1070                 if (WIFEXITED(status))
1071                 {
1072                     if (WEXITSTATUS(status) != 0)
1073                     {
1074                         userdata->exitcode = WEXITSTATUS(status);
1075                     }
1076                 }
1077                 else
1078                 {
1079                     userdata->exitcode = G_SPAWN_ERROR_FAILED;
1080                 }
1081 #else
1082                 if (status != 0)
1083                 {
1084                     userdata->exitcode = status;
1085                 }
1086 #endif
1087                 if (status == 0 && userdata->extcap_stderr != NULL)
1088                 {
1089                     userdata->exitcode = 1;
1090                 }
1091             }
1092             g_source_remove(interface_opts.extcap_child_watch);
1093             interface_opts.extcap_child_watch = 0;
1094
1095             capture_opts->ifaces = g_array_remove_index(capture_opts->ifaces, i);
1096             g_array_insert_val(capture_opts->ifaces, i, interface_opts);
1097             break;
1098         }
1099     }
1100 }
1101
1102 static
1103 GPtrArray *extcap_prepare_arguments(interface_options interface_opts)
1104 {
1105     GPtrArray *result = NULL;
1106
1107     if (interface_opts.if_type == IF_EXTCAP)
1108     {
1109         result = g_ptr_array_new();
1110
1111 #define add_arg(X) g_ptr_array_add(result, g_strdup(X))
1112
1113         add_arg(interface_opts.extcap);
1114         add_arg(EXTCAP_ARGUMENT_RUN_CAPTURE);
1115         add_arg(EXTCAP_ARGUMENT_INTERFACE);
1116         add_arg(interface_opts.name);
1117         if (interface_opts.cfilter && strlen(interface_opts.cfilter) > 0)
1118         {
1119             add_arg(EXTCAP_ARGUMENT_CAPTURE_FILTER);
1120             add_arg(interface_opts.cfilter);
1121         }
1122         add_arg(EXTCAP_ARGUMENT_RUN_PIPE);
1123         add_arg(interface_opts.extcap_fifo);
1124         if (interface_opts.extcap_args == NULL || g_hash_table_size(interface_opts.extcap_args) == 0)
1125         {
1126             /* User did not perform interface configuration.
1127              *
1128              * Check if there are any boolean flags that are set by default
1129              * and hence their argument should be added.
1130              */
1131             GList *arglist;
1132             GList *elem;
1133
1134             arglist = extcap_get_if_configuration(interface_opts.name);
1135             for (elem = g_list_first(arglist); elem; elem = elem->next)
1136             {
1137                 GList *arg_list;
1138                 extcap_arg *arg_iter;
1139
1140                 if (elem->data == NULL)
1141                 {
1142                     continue;
1143                 }
1144
1145                 arg_list = g_list_first((GList *)elem->data);
1146                 while (arg_list != NULL)
1147                 {
1148                     const gchar *stored = NULL, * defval = NULL;
1149                     /* In case of boolflags only first element in arg_list is relevant. */
1150                     arg_iter = (extcap_arg *)(arg_list->data);
1151                     if (arg_iter->pref_valptr != NULL)
1152                     {
1153                         stored = *arg_iter->pref_valptr;
1154                     }
1155
1156                     if (arg_iter->default_complex != NULL && arg_iter->default_complex->_val != NULL)
1157                     {
1158                         defval = arg_iter->default_complex->_val;
1159                     }
1160
1161                     /* Different data in storage then set for default */
1162                     if (g_strcmp0(stored, defval) != 0)
1163                     {
1164                         if (arg_iter->arg_type == EXTCAP_ARG_BOOLFLAG)
1165                         {
1166                             if (g_strcmp0(stored, "true") == 0)
1167                             {
1168                                 add_arg(arg_iter->call);
1169                             }
1170                         }
1171                         else
1172                         {
1173                             add_arg(arg_iter->call);
1174                             add_arg(stored);
1175                         }
1176                     }
1177                     else if (arg_iter->arg_type == EXTCAP_ARG_BOOLFLAG)
1178                     {
1179                         if (extcap_complex_get_bool(arg_iter->default_complex))
1180                         {
1181                             add_arg(arg_iter->call);
1182                         }
1183                     }
1184
1185                     arg_list = arg_list->next;
1186                 }
1187             }
1188
1189             extcap_free_if_configuration(arglist, TRUE);
1190         }
1191         else
1192         {
1193             g_hash_table_foreach_remove(interface_opts.extcap_args, extcap_add_arg_and_remove_cb, result);
1194         }
1195         add_arg(NULL);
1196 #undef add_arg
1197
1198     }
1199
1200     return result;
1201 }
1202
1203 /* call mkfifo for each extcap,
1204  * returns FALSE if there's an error creating a FIFO */
1205 gboolean
1206 extcap_init_interfaces(capture_options *capture_opts)
1207 {
1208     guint i;
1209     interface_options interface_opts;
1210     extcap_userdata *userdata;
1211
1212     for (i = 0; i < capture_opts->ifaces->len; i++)
1213     {
1214         GPtrArray *args = NULL;
1215         GPid pid = INVALID_EXTCAP_PID;
1216
1217         interface_opts = g_array_index(capture_opts->ifaces, interface_options, i);
1218
1219         /* skip native interfaces */
1220         if (interface_opts.if_type != IF_EXTCAP)
1221         {
1222             continue;
1223         }
1224
1225         /* create pipe for fifo */
1226         if (!extcap_create_pipe(&interface_opts.extcap_fifo))
1227         {
1228             return FALSE;
1229         }
1230
1231         /* Create extcap call */
1232         args = extcap_prepare_arguments(interface_opts);
1233
1234         userdata = g_new0(extcap_userdata, 1);
1235
1236         pid = extcap_spawn_async(userdata, args);
1237
1238         g_ptr_array_foreach(args, (GFunc)g_free, NULL);
1239         g_ptr_array_free(args, TRUE);
1240
1241         if (pid == INVALID_EXTCAP_PID)
1242         {
1243             g_free(userdata);
1244             continue;
1245         }
1246
1247         interface_opts.extcap_pid = pid;
1248
1249         interface_opts.extcap_child_watch =
1250             g_child_watch_add(pid, extcap_child_watch_cb, (gpointer)capture_opts);
1251
1252 #ifdef _WIN32
1253         /* On Windows, wait for extcap to connect to named pipe.
1254          * Some extcaps will present UAC screen to user.
1255          * 30 second timeout should be reasonable timeout for extcap to
1256          * connect to named pipe (including user interaction).
1257          * Wait on multiple object in case of extcap termination
1258          * without opening pipe.
1259          *
1260          * Minimum supported version of Windows: XP / Server 2003.
1261          */
1262         if (pid != INVALID_EXTCAP_PID)
1263         {
1264             extcap_wait_for_pipe(pipe_h, pid);
1265         }
1266
1267 #endif
1268
1269         interface_opts.extcap_userdata = (gpointer) userdata;
1270
1271         capture_opts->ifaces = g_array_remove_index(capture_opts->ifaces, i);
1272         g_array_insert_val(capture_opts->ifaces, i, interface_opts);
1273     }
1274
1275     return TRUE;
1276 }
1277
1278 #ifdef _WIN32
1279 /* called by capture_sync to get the CreatNamedPipe handle*/
1280 HANDLE
1281 extcap_get_win32_handle()
1282 {
1283     return pipe_h;
1284 }
1285 #endif
1286
1287 gboolean extcap_create_pipe(char **fifo)
1288 {
1289 #ifdef _WIN32
1290     gchar timestr[ 14 + 1 ];
1291     time_t current_time;
1292
1293     gchar *pipename = NULL;
1294
1295     SECURITY_ATTRIBUTES security;
1296     /* create pipename */
1297     current_time = time(NULL);
1298     /*
1299      * XXX - we trust Windows not to return a time before the Epoch here,
1300      * so we won't get a null pointer back from localtime().
1301      */
1302     strftime(timestr, sizeof(timestr), "%Y%m%d%H%M%S", localtime(&current_time));
1303     pipename = g_strconcat("\\\\.\\pipe\\", EXTCAP_PIPE_PREFIX, "_", timestr, NULL);
1304
1305     /* Security struct to enable Inheritable HANDLE */
1306     memset(&security, 0, sizeof(SECURITY_ATTRIBUTES));
1307     security.nLength = sizeof(SECURITY_ATTRIBUTES);
1308     security.bInheritHandle = TRUE;
1309     security.lpSecurityDescriptor = NULL;
1310
1311     /* create a namedPipe*/
1312     pipe_h = CreateNamedPipe(
1313                  utf_8to16(pipename),
1314                  PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED,
1315                  PIPE_TYPE_MESSAGE | PIPE_READMODE_MESSAGE | PIPE_WAIT,
1316                  5, 65536, 65536,
1317                  300,
1318                  &security);
1319
1320     if (pipe_h == INVALID_HANDLE_VALUE)
1321     {
1322         g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, "\nError creating pipe => (%d)", GetLastError());
1323         return FALSE;
1324     }
1325     else
1326     {
1327         g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, "\nWireshark Created pipe =>(%s)", pipename);
1328         *fifo = g_strdup(pipename);
1329     }
1330 #else
1331     gchar *temp_name = NULL;
1332     int fd = 0;
1333
1334     if ((fd = create_tempfile(&temp_name, EXTCAP_PIPE_PREFIX, NULL)) < 0)
1335     {
1336         return FALSE;
1337     }
1338
1339     ws_close(fd);
1340
1341     g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG,
1342           "Extcap - Creating fifo: %s", temp_name);
1343
1344     if (file_exists(temp_name))
1345     {
1346         ws_unlink(temp_name);
1347     }
1348
1349     if (mkfifo(temp_name, 0600) == 0)
1350     {
1351         *fifo = g_strdup(temp_name);
1352     }
1353 #endif
1354
1355     return TRUE;
1356 }
1357
1358 /*
1359  * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
1360  *
1361  * Local variables:
1362  * c-basic-offset: 4
1363  * tab-width: 8
1364  * indent-tabs-mode: nil
1365  * End:
1366  *
1367  * vi: set shiftwidth=4 tabstop=8 expandtab:
1368  * :indentSize=4:tabSize=8:noTabs=true:
1369  */