SystemConfiguration.fproj/LinkConfiguration.c

   1 /*
   2  * Copyright (c) 2002-2007, 2010, 2011, 2013, 2015-2017 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 /*
  25  * Modification History
  26  *
  27  * October 21, 2000             Allan Nathanson <ajn@apple.com>
  28  * - initial revision
  29  */
  30
  31
  32 #include <unistd.h>
  33 #define KERNEL_PRIVATE
  34 #include <sys/ioctl.h>
  35 #undef  KERNEL_PRIVATE
  36 #include <sys/socket.h>
  37 #include <net/ethernet.h>
  38 #include <net/if.h>
  39 #include <net/if_vlan_var.h>
  40 #include <net/if_media.h>
  41 #include <net/if_types.h>
  42 #include <netinet/in.h>
  43 #include <netinet/ip6.h>                        // for IPV6_MMTU
  44
  45 #include "SCNetworkConfigurationInternal.h"     // for __SCNetworkInterfaceCreatePrivate
  46
  47 #include <IOKit/IOKitLib.h>
  48 #include <IOKit/network/IONetworkInterface.h>
  49 #include <IOKit/network/IONetworkController.h>
  50 #include "dy_framework.h"
  51
  52
  53 #pragma mark -
  54 #pragma mark Capabilities
  55
  56
  57 // the following table needs to keep the capabilitiy names and values
  58 // between the <SystemConfiguration/SCSchemaDefinitionsPrivate.h> and
  59 // <net/if.h> headers in sync.
  60 static const struct {
  61         const CFStringRef       *name;
  62         Boolean                 readwrite;
  63         int                     val;
  64 } capabilityMappings[] = {
  65 #ifdef  SIOCGIFCAP
  66         { &kSCPropNetEthernetCapabilityRXCSUM,          TRUE,   IFCAP_RXCSUM            },      // can offload checksum on RX
  67         { &kSCPropNetEthernetCapabilityTXCSUM,          TRUE,   IFCAP_TXCSUM            },      // can offload checksum on TX
  68         { &kSCPropNetEthernetCapabilityVLAN_MTU,        FALSE,  IFCAP_VLAN_MTU          },      // VLAN-compatible MTU
  69         { &kSCPropNetEthernetCapabilityVLAN_HWTAGGING,  FALSE,  IFCAP_VLAN_HWTAGGING    },      // hardware VLAN tag support
  70         { &kSCPropNetEthernetCapabilityJUMBO_MTU,       FALSE,  IFCAP_JUMBO_MTU         },      // 9000 byte MTU supported
  71         { &kSCPropNetEthernetCapabilityTSO,             TRUE,   IFCAP_TSO               },      // can do TCP/TCP6 Segmentation Offload
  72         { &kSCPropNetEthernetCapabilityTSO4,            FALSE,  IFCAP_TSO4              },      // can do TCP Segmentation Offload
  73         { &kSCPropNetEthernetCapabilityTSO6,            FALSE,  IFCAP_TSO6              },      // can do TCP6 Segmentation Offload
  74         { &kSCPropNetEthernetCapabilityLRO,             TRUE,   IFCAP_LRO               },      // can do Large Receive Offload
  75         { &kSCPropNetEthernetCapabilityAV,              TRUE,   IFCAP_AV                },      // can do 802.1 AV Bridging
  76 #endif  // SIOCGIFCAP
  77 };
  78
  79
  80 static CFIndex
  81 findCapability(CFStringRef capability)
  82 {
  83         for (size_t i = 0; i < sizeof(capabilityMappings) / sizeof(capabilityMappings[0]); i++) {
  84                 if (CFEqual(capability, *capabilityMappings[i].name)) {
  85                         return i;
  86                 }
  87         }
  88
  89         return kCFNotFound;
  90 }
  91
  92
  93 static Boolean
  94 __getCapabilities(CFStringRef   interfaceName,
  95                   int           *current,
  96                   int           *available)
  97 {
  98 #ifdef  SIOCGIFCAP
  99         struct ifreq    ifr;
 100         Boolean         ok              = FALSE;
 101         int             sock            = -1;
 102
 103         bzero((void *)&ifr, sizeof(ifr));
 104         if (_SC_cfstring_to_cstring(interfaceName, ifr.ifr_name, sizeof(ifr.ifr_name), kCFStringEncodingASCII) == NULL) {
 105                 SC_log(LOG_NOTICE, "could not convert interface name");
 106                 _SCErrorSet(kSCStatusInvalidArgument);
 107                 return FALSE;
 108         }
 109
 110         sock = socket(AF_INET, SOCK_DGRAM, 0);
 111         if (sock == -1) {
 112                 _SCErrorSet(errno);
 113                 SC_log(LOG_ERR, "socket() failed: %s", strerror(errno));
 114                 return FALSE;
 115         }
 116
 117         if (ioctl(sock, SIOCGIFCAP, (caddr_t)&ifr) == -1) {
 118                 _SCErrorSet(errno);
 119                 switch (errno) {
 120                         case EBUSY :
 121                         case ENXIO :
 122                                 break;
 123                         default :
 124                                 SC_log(LOG_NOTICE, "ioctl(SIOCGIFCAP) failed: %s", strerror(errno));
 125                 }
 126                 goto done;
 127         }
 128
 129         if (current   != NULL)  *current   = ifr.ifr_curcap;
 130         if (available != NULL)  *available = ifr.ifr_reqcap;
 131
 132         ok = TRUE;
 133
 134     done :
 135
 136         (void)close(sock);
 137         return ok;
 138 #else   // SIOCGIFCAP
 139         if (current != NULL)    *current = 0;
 140         if (available != NULL)  *available = 0;
 141         return TRUE;
 142 #endif  // SIOCGIFCAP
 143 }
 144
 145
 146 int
 147 __SCNetworkInterfaceCreateCapabilities(SCNetworkInterfaceRef    interface,
 148                                        int                      capability_base,
 149                                        CFDictionaryRef          capability_options)
 150 {
 151         int             cap_available   = 0;
 152         int             cap_current     = capability_base;
 153         CFStringRef     interfaceName;
 154
 155         if (!isA_SCNetworkInterface(interface)) {
 156                 _SCErrorSet(kSCStatusInvalidArgument);
 157                 goto done;
 158         }
 159
 160         interfaceName = SCNetworkInterfaceGetBSDName(interface);
 161         if (interfaceName == NULL) {
 162                 _SCErrorSet(kSCStatusInvalidArgument);
 163                 goto done;
 164         }
 165
 166         if (!__getCapabilities(interfaceName,
 167                                (capability_base == -1) ? &cap_current : NULL,
 168                                &cap_available)) {
 169                 goto done;
 170         }
 171
 172         if (cap_available == 0) {
 173                 goto done;
 174         }
 175
 176         if (capability_options == NULL) {
 177                 goto done;
 178         }
 179
 180         for (size_t i = 0; i < sizeof(capabilityMappings) / sizeof(capabilityMappings[0]); i++) {
 181                 int             cap_val;
 182                 CFTypeRef       val;
 183
 184                 if (((cap_available & capabilityMappings[i].val) != 0) &&
 185                     capabilityMappings[i].readwrite &&
 186                     CFDictionaryGetValueIfPresent(capability_options,
 187                                                   *capabilityMappings[i].name,
 188                                                   &val) &&
 189                     isA_CFNumber(val) &&
 190                     CFNumberGetValue(val, kCFNumberIntType, &cap_val)) {
 191                         // update capability
 192                         if (cap_val != 0) {
 193                                 cap_current |= (cap_available & capabilityMappings[i].val);
 194                         } else {
 195                                 cap_current &= ~capabilityMappings[i].val;
 196                         }
 197
 198                         // don't process again
 199                         cap_available &= ~capabilityMappings[i].val;
 200                 }
 201         }
 202
 203     done :
 204
 205         return cap_current;
 206 }
 207
 208
 209 CFTypeRef
 210 SCNetworkInterfaceCopyCapability(SCNetworkInterfaceRef  interface,
 211                                  CFStringRef            capability)
 212 {
 213         int             cap_current     = 0;
 214         int             cap_available   = 0;
 215         int             cap_val;
 216         CFStringRef     interfaceName;
 217         CFTypeRef       val             = NULL;
 218
 219         if (!isA_SCNetworkInterface(interface)) {
 220                 _SCErrorSet(kSCStatusInvalidArgument);
 221                 return NULL;
 222         }
 223
 224         interfaceName = SCNetworkInterfaceGetBSDName(interface);
 225         if (interfaceName == NULL) {
 226                 _SCErrorSet(kSCStatusInvalidArgument);
 227                 return NULL;
 228         }
 229
 230         if (!__getCapabilities(interfaceName, &cap_current, &cap_available)) {
 231                 return NULL;
 232         }
 233
 234         if (capability == NULL) {
 235                 CFMutableDictionaryRef  all     = NULL;
 236
 237                 // if ALL capabilities requested
 238                 for (size_t i = 0; i < sizeof(capabilityMappings) / sizeof(capabilityMappings[0]); i++) {
 239                         if ((cap_available & capabilityMappings[i].val) == capabilityMappings[i].val) {
 240                                 if (all == NULL) {
 241                                         all = CFDictionaryCreateMutable(NULL,
 242                                                                         0,
 243                                                                         &kCFTypeDictionaryKeyCallBacks,
 244                                                                         &kCFTypeDictionaryValueCallBacks);
 245                                 }
 246                                 cap_val = ((cap_current & capabilityMappings[i].val) == capabilityMappings[i].val) ? 1 : 0;
 247                                 val = CFNumberCreate(NULL, kCFNumberIntType, &cap_val);
 248                                 CFDictionarySetValue(all, *capabilityMappings[i].name, val);
 249                                 CFRelease(val);
 250                                 cap_available &= ~capabilityMappings[i].val;
 251                         }
 252                 }
 253
 254                 val = all;
 255         } else {
 256                 CFIndex         i;
 257
 258                 i = findCapability(capability);
 259                 if (i == kCFNotFound) {
 260                         // if unknown capability
 261                         _SCErrorSet(kSCStatusInvalidArgument);
 262                         return NULL;
 263                 }
 264
 265                 if ((cap_available & capabilityMappings[i].val) != capabilityMappings[i].val) {
 266                         // if capability not available
 267                         _SCErrorSet(kSCStatusInvalidArgument);
 268                         return NULL;
 269                 }
 270
 271                 cap_val = ((cap_current & capabilityMappings[i].val) == capabilityMappings[i].val) ? 1 : 0;
 272                 val = CFNumberCreate(NULL, kCFNumberIntType, &cap_val);
 273         }
 274
 275         return val;
 276 }
 277
 278
 279 Boolean
 280 SCNetworkInterfaceSetCapability(SCNetworkInterfaceRef   interface,
 281                                 CFStringRef             capability,
 282                                 CFTypeRef               newValue)
 283 {
 284         int                     cap_available           = 0;
 285         CFDictionaryRef         configuration;
 286         CFIndex                 i;
 287         CFStringRef             interfaceName;
 288         CFMutableDictionaryRef  newConfiguration        = NULL;
 289         Boolean                 ok                      = FALSE;
 290
 291         if (!isA_SCNetworkInterface(interface)) {
 292                 _SCErrorSet(kSCStatusInvalidArgument);
 293                 return FALSE;
 294         }
 295
 296         interfaceName = SCNetworkInterfaceGetBSDName(interface);
 297         if (interfaceName == NULL) {
 298                 // if no interface name
 299                 _SCErrorSet(kSCStatusInvalidArgument);
 300                 return FALSE;
 301         }
 302
 303         i = findCapability(capability);
 304         if (i == kCFNotFound) {
 305                 // if unknown capability
 306                 _SCErrorSet(kSCStatusInvalidArgument);
 307                 return FALSE;
 308         }
 309
 310         if (!capabilityMappings[i].readwrite) {
 311                 // if not read-write
 312                 _SCErrorSet(kSCStatusInvalidArgument);
 313                 return FALSE;
 314         }
 315
 316         if ((newValue != NULL) && !isA_CFNumber(newValue)) {
 317                 // all values must (for now) be CFNumber[0 or 1]'s
 318                 _SCErrorSet(kSCStatusInvalidArgument);
 319                 return FALSE;
 320         }
 321
 322         if (!__getCapabilities(interfaceName, NULL, &cap_available)) {
 323                 return FALSE;
 324         }
 325
 326         if ((cap_available & capabilityMappings[i].val) == 0) {
 327                 // if capability not available
 328                 _SCErrorSet(kSCStatusInvalidArgument);
 329                 return FALSE;
 330         }
 331
 332         configuration = SCNetworkInterfaceGetConfiguration(interface);
 333         if (configuration == NULL) {
 334                 newConfiguration = CFDictionaryCreateMutable(NULL,
 335                                                              0,
 336                                                              &kCFTypeDictionaryKeyCallBacks,
 337                                                              &kCFTypeDictionaryValueCallBacks);
 338         } else {
 339                 newConfiguration = CFDictionaryCreateMutableCopy(NULL, 0, configuration);
 340                 CFDictionaryRemoveValue(newConfiguration, kSCResvInactive);
 341         }
 342
 343         if ((newValue != NULL)) {
 344                 CFDictionarySetValue(newConfiguration, capability, newValue);
 345         } else {
 346                 CFDictionaryRemoveValue(newConfiguration, capability);
 347                 if (CFDictionaryGetCount(newConfiguration) == 0) {
 348                         CFRelease(newConfiguration);
 349                         newConfiguration = NULL;
 350                 }
 351         }
 352
 353         ok = SCNetworkInterfaceSetConfiguration(interface, newConfiguration);
 354         if (newConfiguration != NULL) CFRelease(newConfiguration);
 355
 356         return ok;
 357 }
 358
 359
 360 #pragma mark -
 361 #pragma mark Media Options
 362
 363
 364 static const struct ifmedia_description ifm_subtype_shared_descriptions[] =
 365     IFM_SUBTYPE_SHARED_DESCRIPTIONS;
 366
 367 static const struct ifmedia_description ifm_subtype_ethernet_descriptions[] =
 368     IFM_SUBTYPE_ETHERNET_DESCRIPTIONS;
 369
 370 static const struct ifmedia_description ifm_subtype_ieee80211_descriptions[] =
 371     IFM_SUBTYPE_IEEE80211_DESCRIPTIONS;
 372
 373 static const struct ifmedia_description ifm_shared_option_descriptions[] =
 374     IFM_SHARED_OPTION_DESCRIPTIONS;
 375
 376 static const struct ifmedia_description ifm_subtype_ethernet_option_descriptions[] =
 377     IFM_SUBTYPE_ETHERNET_OPTION_DESCRIPTIONS;
 378
 379 static const struct ifmedia_description ifm_subtype_ieee80211_option_descriptions[] =
 380     IFM_SUBTYPE_IEEE80211_OPTION_DESCRIPTIONS;
 381
 382
 383 static void
 384 __freeMediaList(struct ifmediareq *ifm)
 385 {
 386         if (ifm->ifm_ulist != NULL) CFAllocatorDeallocate(NULL, ifm->ifm_ulist);
 387         CFAllocatorDeallocate(NULL, ifm);
 388         return;
 389 }
 390
 391
 392 static struct ifmediareq *
 393 __copyMediaList(CFStringRef interfaceName)
 394 {
 395         struct ifmediareq       *ifm;
 396         Boolean                 ok      = FALSE;
 397         int                     sock    = -1;
 398
 399         ifm = (struct ifmediareq *)CFAllocatorAllocate(NULL, sizeof(struct ifmediareq), 0);
 400         bzero((void *)ifm, sizeof(*ifm));
 401
 402         if (_SC_cfstring_to_cstring(interfaceName, ifm->ifm_name, sizeof(ifm->ifm_name), kCFStringEncodingASCII) == NULL) {
 403                 SC_log(LOG_NOTICE, "could not convert interface name");
 404                 goto done;
 405         }
 406
 407         sock = socket(AF_INET, SOCK_DGRAM, 0);
 408         if (sock == -1) {
 409                 SC_log(LOG_ERR, "socket() failed: %s", strerror(errno));
 410                 goto done;
 411         }
 412
 413         if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)ifm) == -1) {
 414 //              SC_log(LOG_NOTICE, "ioctl(SIOCGIFMEDIA) failed: %s", strerror(errno));
 415                 goto done;
 416         }
 417
 418         if (ifm->ifm_count > 0) {
 419                 ifm->ifm_ulist = (int *)CFAllocatorAllocate(NULL, ifm->ifm_count * sizeof(int), 0);
 420                 if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)ifm) == -1) {
 421                         SC_log(LOG_NOTICE, "ioctl(SIOCGIFMEDIA) failed: %s", strerror(errno));
 422                         goto done;
 423                 }
 424         }
 425
 426         ok = TRUE;
 427
 428     done :
 429
 430         if (sock != -1) (void)close(sock);
 431         if (!ok) {
 432                 __freeMediaList(ifm);
 433                 ifm = NULL;
 434                 _SCErrorSet(kSCStatusFailed);
 435         }
 436         return ifm;
 437 }
 438
 439
 440 static CFDictionaryRef
 441 __createMediaDictionary(int media_options, Boolean filter)
 442 {
 443         CFMutableDictionaryRef                  dict                    = NULL;
 444         int                                     i;
 445         const struct ifmedia_description        *option_descriptions    = NULL;
 446         CFMutableArrayRef                       options                 = NULL;
 447         const struct ifmedia_description        *subtype_descriptions   = NULL;
 448         CFStringRef                             val;
 449
 450         if (filter &&
 451             ((IFM_SUBTYPE(media_options) == IFM_NONE) ||
 452              ((IFM_OPTIONS(media_options) & IFM_LOOP) != 0))) {
 453                 return NULL;    /* filter */
 454         }
 455
 456         switch (IFM_TYPE(media_options)) {
 457                 case IFM_ETHER :
 458                         option_descriptions  = ifm_subtype_ethernet_option_descriptions;
 459                         subtype_descriptions = ifm_subtype_ethernet_descriptions;
 460                         break;
 461                 case IFM_IEEE80211 :
 462                         option_descriptions  = ifm_subtype_ieee80211_option_descriptions;
 463                         subtype_descriptions = ifm_subtype_ieee80211_descriptions;
 464                         break;
 465                 default :
 466                         return NULL;
 467         }
 468
 469         dict = CFDictionaryCreateMutable(NULL,
 470                                          0,
 471                                          &kCFTypeDictionaryKeyCallBacks,
 472                                          &kCFTypeDictionaryValueCallBacks);
 473
 474         /* subtype */
 475
 476         val = NULL;
 477         for (i = 0; !val && ifm_subtype_shared_descriptions[i].ifmt_string; i++) {
 478                 if (IFM_SUBTYPE(media_options) == ifm_subtype_shared_descriptions[i].ifmt_word) {
 479                         val = CFStringCreateWithCString(NULL,
 480                                                         ifm_subtype_shared_descriptions[i].ifmt_string,
 481                                                         kCFStringEncodingASCII);
 482                         break;
 483                 }
 484         }
 485
 486         if (subtype_descriptions != NULL) {
 487                 for (i = 0; !val && subtype_descriptions[i].ifmt_string; i++) {
 488                         if (IFM_SUBTYPE(media_options) == subtype_descriptions[i].ifmt_word) {
 489                                 val = CFStringCreateWithCString(NULL,
 490                                                                 subtype_descriptions[i].ifmt_string,
 491                                                                 kCFStringEncodingASCII);
 492                                 break;
 493                         }
 494                 }
 495         }
 496
 497         if (val) {
 498                 CFDictionaryAddValue(dict, kSCPropNetEthernetMediaSubType, val);
 499                 CFRelease(val);
 500         }
 501
 502         /* options */
 503
 504         options = CFArrayCreateMutable(NULL, 0, &kCFTypeArrayCallBacks);
 505
 506         for (i = 0; (IFM_OPTIONS(media_options) != 0) && (ifm_shared_option_descriptions[i].ifmt_string != NULL); i++) {
 507                 if ((media_options & ifm_shared_option_descriptions[i].ifmt_word) != 0) {
 508                         val = CFStringCreateWithCString(NULL,
 509                                                         ifm_shared_option_descriptions[i].ifmt_string,
 510                                                         kCFStringEncodingASCII);
 511                         CFArrayAppendValue(options, val);
 512                         CFRelease(val);
 513
 514                         media_options &= ~ifm_shared_option_descriptions[i].ifmt_word;
 515                 }
 516         }
 517
 518         if (option_descriptions != NULL) {
 519                 for (i = 0; (IFM_OPTIONS(media_options) != 0) && (option_descriptions[i].ifmt_string != NULL); i++) {
 520                         if ((media_options & option_descriptions[i].ifmt_word) != 0) {
 521                                 val = CFStringCreateWithCString(NULL,
 522                                                                 option_descriptions[i].ifmt_string,
 523                                                                 kCFStringEncodingASCII);
 524                                 CFArrayAppendValue(options, val);
 525                                 CFRelease(val);
 526
 527                                 media_options &= ~option_descriptions[i].ifmt_word;
 528                         }
 529                 }
 530         }
 531
 532         CFDictionaryAddValue(dict, kSCPropNetEthernetMediaOptions, options);
 533         CFRelease(options);
 534
 535         return dict;
 536 }
 537
 538
 539 int
 540 __SCNetworkInterfaceCreateMediaOptions(SCNetworkInterfaceRef interface, CFDictionaryRef media_options)
 541 {
 542         CFIndex                                 i;
 543         struct ifmediareq                       *ifm;
 544         int                                     ifm_new = -1;
 545         CFStringRef                             interfaceName;
 546         Boolean                                 match;
 547         CFIndex                                 n;
 548         const struct ifmedia_description        *option_descriptions    = NULL;
 549         CFArrayRef                              options;
 550         char                                    *str;
 551         const struct ifmedia_description        *subtype_descriptions   = NULL;
 552         CFStringRef                             val;
 553
 554         if (!isA_SCNetworkInterface(interface)) {
 555                 _SCErrorSet(kSCStatusInvalidArgument);
 556                 return -1;
 557         }
 558
 559         interfaceName = SCNetworkInterfaceGetBSDName(interface);
 560         if (interfaceName == NULL) {
 561                 _SCErrorSet(kSCStatusInvalidArgument);
 562                 return -1;
 563         }
 564
 565         /* set type */
 566
 567         ifm = __copyMediaList(interfaceName);
 568         if (ifm != NULL) {
 569                 if (ifm->ifm_count > 0) {
 570                         ifm_new = IFM_TYPE(ifm->ifm_ulist[0]);
 571                 }
 572                 __freeMediaList(ifm);
 573         }
 574
 575         if (ifm_new == -1) {
 576                 // if we cannot determine the media type for the interface
 577                 return -1;
 578         }
 579
 580         switch (IFM_TYPE(ifm_new)) {
 581                 case IFM_ETHER :
 582                         option_descriptions  = ifm_subtype_ethernet_option_descriptions;
 583                         subtype_descriptions = ifm_subtype_ethernet_descriptions;
 584                         break;
 585                 case IFM_IEEE80211 :
 586                         option_descriptions  = ifm_subtype_ieee80211_option_descriptions;
 587                         subtype_descriptions = ifm_subtype_ieee80211_descriptions;
 588                         break;
 589         }
 590
 591         /* set subtype */
 592
 593         val = CFDictionaryGetValue(media_options, kSCPropNetEthernetMediaSubType);
 594         if (!isA_CFString(val)) {
 595                 return -1;
 596         }
 597
 598         str = _SC_cfstring_to_cstring(val, NULL, 0, kCFStringEncodingASCII);
 599         if (str == NULL) {
 600                 return -1;
 601         }
 602
 603         match = FALSE;
 604         for (i = 0; !match && ifm_subtype_shared_descriptions[i].ifmt_string; i++) {
 605                 if (strcasecmp(str, ifm_subtype_shared_descriptions[i].ifmt_string) == 0) {
 606                         ifm_new |= ifm_subtype_shared_descriptions[i].ifmt_word;
 607                         match = TRUE;
 608                         break;
 609                 }
 610         }
 611
 612         if (subtype_descriptions != NULL) {
 613                 for (i = 0; !match && subtype_descriptions[i].ifmt_string; i++) {
 614                         if (strcasecmp(str, subtype_descriptions[i].ifmt_string) == 0) {
 615                                 ifm_new |= subtype_descriptions[i].ifmt_word;
 616                                 match = TRUE;
 617                                 break;
 618                         }
 619                 }
 620         }
 621
 622         CFAllocatorDeallocate(NULL, str);
 623
 624         if (!match) {
 625                 return -1;      /* if no subtype */
 626         }
 627
 628         /* set options */
 629
 630         options = CFDictionaryGetValue(media_options, kSCPropNetEthernetMediaOptions);
 631         if (!isA_CFArray(options)) {
 632                 return -1;
 633         }
 634
 635         n = CFArrayGetCount(options);
 636         for (i = 0; i < n; i++) {
 637                 CFIndex         j;
 638
 639                 val = CFArrayGetValueAtIndex(options, i);
 640                 if (!isA_CFString(val)) {
 641                         return -1;
 642                 }
 643
 644                 str = _SC_cfstring_to_cstring(val, NULL, 0, kCFStringEncodingASCII);
 645                 if (str == NULL) {
 646                         return -1;
 647                 }
 648
 649
 650                 match = FALSE;
 651                 for (j = 0; !match && ifm_shared_option_descriptions[j].ifmt_string; j++) {
 652                         if (strcasecmp(str, ifm_shared_option_descriptions[j].ifmt_string) == 0) {
 653                                 ifm_new |= ifm_shared_option_descriptions[j].ifmt_word;
 654                                 match = TRUE;
 655                                 break;
 656                         }
 657                 }
 658
 659                 if (option_descriptions != NULL) {
 660                         for (j = 0; !match && option_descriptions[j].ifmt_string; j++) {
 661                                 if (strcasecmp(str, option_descriptions[j].ifmt_string) == 0) {
 662                                         ifm_new |= option_descriptions[j].ifmt_word;
 663                                         match = TRUE;
 664                                         break;
 665                                 }
 666                         }
 667                 }
 668
 669                 CFAllocatorDeallocate(NULL, str);
 670
 671                 if (!match) {
 672                         return -1;      /* if no option */
 673                 }
 674         }
 675
 676         return ifm_new;
 677 }
 678
 679
 680 Boolean
 681 SCNetworkInterfaceCopyMediaOptions(SCNetworkInterfaceRef        interface,
 682                                    CFDictionaryRef              *current,
 683                                    CFDictionaryRef              *active,
 684                                    CFArrayRef                   *available,
 685                                    Boolean                      filter)
 686 {
 687         int                     i;
 688         struct ifmediareq       *ifm;
 689         CFStringRef             interfaceName;
 690
 691         if (!isA_SCNetworkInterface(interface)) {
 692                 _SCErrorSet(kSCStatusInvalidArgument);
 693                 return FALSE;
 694         }
 695
 696         interfaceName = SCNetworkInterfaceGetBSDName(interface);
 697         if (interfaceName == NULL) {
 698                 _SCErrorSet(kSCStatusInvalidArgument);
 699                 return FALSE;
 700         }
 701
 702         ifm = __copyMediaList(interfaceName);
 703         if (ifm == NULL) {
 704                 return FALSE;
 705         }
 706
 707         if (active != NULL)     *active    = NULL;
 708         if (current != NULL)    *current   = NULL;
 709         if (available != NULL) {
 710                 CFMutableArrayRef       media_options;
 711
 712                 media_options = CFArrayCreateMutable(NULL, 0, &kCFTypeArrayCallBacks);
 713                 for (i = 0; i < ifm->ifm_count; i++) {
 714                         CFDictionaryRef options;
 715
 716                         options = __createMediaDictionary(ifm->ifm_ulist[i], filter);
 717                         if (options == NULL) {
 718                                 continue;
 719                         }
 720
 721                         if ((active != NULL)  && (*active == NULL)  && (ifm->ifm_active == ifm->ifm_ulist[i])) {
 722                                 *active  = CFRetain(options);
 723                         }
 724
 725                         if ((current != NULL) && (*current == NULL) && (ifm->ifm_current == ifm->ifm_ulist[i])) {
 726                                 *current = CFRetain(options);
 727                         }
 728
 729                         if (!CFArrayContainsValue(media_options, CFRangeMake(0, CFArrayGetCount(media_options)), options)) {
 730                                 CFArrayAppendValue(media_options, options);
 731                         }
 732
 733                         CFRelease(options);
 734                 }
 735                 *available = (CFArrayRef)media_options;
 736         }
 737
 738         if ((active != NULL)  && (*active == NULL)) {
 739                 *active = __createMediaDictionary(ifm->ifm_active, FALSE);
 740         }
 741
 742         if ((current != NULL) && (*current == NULL)) {
 743                 if ((active != NULL) && (ifm->ifm_active == ifm->ifm_current)) {
 744                         if (*active != NULL)    *current = CFRetain(*active);
 745                 } else {
 746                         *current = __createMediaDictionary(ifm->ifm_current, FALSE);
 747                 }
 748         }
 749
 750         __freeMediaList(ifm);
 751         return TRUE;
 752 }
 753
 754
 755 CFArrayRef
 756 SCNetworkInterfaceCopyMediaSubTypes(CFArrayRef  available)
 757 {
 758         CFIndex                 i;
 759         CFIndex                 n;
 760         CFMutableArrayRef       subTypes;
 761
 762         if (!isA_CFArray(available)) {
 763                 _SCErrorSet(kSCStatusInvalidArgument);
 764                 return NULL;
 765         }
 766
 767         subTypes = CFArrayCreateMutable(NULL, 0, &kCFTypeArrayCallBacks);
 768
 769         n = CFArrayGetCount(available);
 770         for (i = 0; i < n; i++) {
 771                 CFDictionaryRef options;
 772                 CFStringRef     subType;
 773
 774                 options = CFArrayGetValueAtIndex(available, i);
 775                 if (!isA_CFDictionary(options)) {
 776                         continue;
 777                 }
 778
 779                 subType = CFDictionaryGetValue(options, kSCPropNetEthernetMediaSubType);
 780                 if (!isA_CFString(subType)) {
 781                         continue;
 782                 }
 783
 784                 if (!CFArrayContainsValue(subTypes, CFRangeMake(0, CFArrayGetCount(subTypes)), subType)) {
 785                         CFArrayAppendValue(subTypes, subType);
 786                 }
 787         }
 788
 789         if (CFArrayGetCount(subTypes) == 0) {
 790                 CFRelease(subTypes);
 791                 subTypes = NULL;
 792                 _SCErrorSet(kSCStatusOK);
 793         }
 794
 795         return subTypes;
 796 }
 797
 798
 799 CFArrayRef
 800 SCNetworkInterfaceCopyMediaSubTypeOptions(CFArrayRef    available,
 801                                           CFStringRef   subType)
 802 {
 803         CFIndex                 i;
 804         CFIndex                 n;
 805         CFMutableArrayRef       subTypeOptions;
 806
 807         if (!isA_CFArray(available)) {
 808                 _SCErrorSet(kSCStatusInvalidArgument);
 809                 return NULL;
 810         }
 811
 812         subTypeOptions = CFArrayCreateMutable(NULL, 0, &kCFTypeArrayCallBacks);
 813
 814         n = CFArrayGetCount(available);
 815         for (i = 0; i < n; i++) {
 816                 CFDictionaryRef options;
 817                 CFArrayRef      mediaOptions;
 818                 CFStringRef     mediaSubType;
 819
 820                 options = CFArrayGetValueAtIndex(available, i);
 821                 if (!isA_CFDictionary(options)) {
 822                         continue;
 823                 }
 824
 825                 mediaSubType = CFDictionaryGetValue(options, kSCPropNetEthernetMediaSubType);
 826                 if (!isA_CFString(mediaSubType) || !CFEqual(subType, mediaSubType)) {
 827                         continue;
 828                 }
 829
 830                 mediaOptions = CFDictionaryGetValue(options, kSCPropNetEthernetMediaOptions);
 831                 if (!isA_CFArray(mediaOptions)) {
 832                         continue;
 833                 }
 834
 835                 if (!CFArrayContainsValue(subTypeOptions, CFRangeMake(0, CFArrayGetCount(subTypeOptions)), mediaOptions)) {
 836                         CFArrayAppendValue(subTypeOptions, mediaOptions);
 837                 }
 838         }
 839
 840         if (CFArrayGetCount(subTypeOptions) == 0) {
 841                 CFRelease(subTypeOptions);
 842                 subTypeOptions = NULL;
 843                 _SCErrorSet(kSCStatusOK);
 844         }
 845
 846         return subTypeOptions;
 847 }
 848
 849
 850 Boolean
 851 _SCNetworkInterfaceIsPhysicalEthernet(SCNetworkInterfaceRef interface)
 852 {
 853         int                     i;
 854         struct ifmediareq       *ifm;
 855         CFStringRef             interfaceName;
 856         Boolean                 realEthernet = FALSE;
 857
 858         if (!isA_SCNetworkInterface(interface)) {
 859                 _SCErrorSet(kSCStatusInvalidArgument);
 860                 return FALSE;
 861         }
 862
 863         interfaceName = SCNetworkInterfaceGetBSDName(interface);
 864         if (interfaceName == NULL) {
 865                 _SCErrorSet(kSCStatusInvalidArgument);
 866                 return FALSE;
 867         }
 868
 869         ifm = __copyMediaList(interfaceName);
 870         if (ifm == NULL) {
 871                 CFStringRef interfaceType;
 872
 873                 interfaceType = SCNetworkInterfaceGetInterfaceType(interface);
 874                 if (CFEqual(interfaceType, kSCNetworkInterfaceTypeEthernet) &&
 875                     !_SCNetworkInterfaceIsTethered(interface) &&
 876                     !_SCNetworkInterfaceIsBluetoothPAN(interface)) {
 877                     // if likely physical ethernet interface
 878                     return TRUE;
 879                 }
 880                 return FALSE;
 881         }
 882         _SCErrorSet(kSCStatusOK);
 883         if (IFM_TYPE(ifm->ifm_current) != IFM_ETHER) {
 884                 goto done;
 885         }
 886         if (ifm->ifm_count == 1
 887             && IFM_SUBTYPE(ifm->ifm_ulist[0]) == IFM_AUTO) {
 888                 /* only support autoselect, not really ethernet */
 889                 goto done;
 890         }
 891         for (i = 0; i < ifm->ifm_count; i++) {
 892                 if ((ifm->ifm_ulist[i] & IFM_FDX) != 0) {
 893                         realEthernet = TRUE;
 894                         break;
 895                 }
 896         }
 897  done:
 898         __freeMediaList(ifm);
 899         return (realEthernet);
 900 }
 901
 902 static Boolean
 903 __getIOMTULimits(char   ifr_name[IFNAMSIZ],
 904                  int    *mtu_min,
 905                  int    *mtu_max)
 906 {
 907         int                     ifType          = 0;
 908         io_iterator_t           io_iter         = 0;
 909         io_registry_entry_t     io_interface    = 0;
 910         io_registry_entry_t     io_controller   = 0;
 911         kern_return_t           kr;
 912         static mach_port_t      masterPort      = MACH_PORT_NULL;
 913         CFMutableDictionaryRef  matchingDict;
 914
 915         /* look for a matching interface in the IORegistry */
 916
 917         if (masterPort == MACH_PORT_NULL) {
 918                 kr = IOMasterPort(MACH_PORT_NULL, &masterPort);
 919                 if (kr != KERN_SUCCESS) {
 920                         return FALSE;
 921                 }
 922         }
 923
 924         matchingDict = IOBSDNameMatching(masterPort, 0, ifr_name);
 925         if (matchingDict) {
 926                 /* Note: IOServiceGetMatchingServices consumes a reference on the 'matchingDict' */
 927                 kr = IOServiceGetMatchingServices(masterPort, matchingDict, &io_iter);
 928                 if ((kr == KERN_SUCCESS) && io_iter) {
 929                     /* should only have a single match */
 930                     io_interface = IOIteratorNext(io_iter);
 931                 }
 932                 if (io_iter)    IOObjectRelease(io_iter);
 933         }
 934
 935         if (io_interface) {
 936                 CFNumberRef     num;
 937
 938                 /*
 939                  * found an interface, get the interface type
 940                  */
 941                 num = IORegistryEntryCreateCFProperty(io_interface, CFSTR(kIOInterfaceType), NULL, kNilOptions);
 942                 if (num) {
 943                         if (isA_CFNumber(num)) {
 944                                 CFNumberGetValue(num, kCFNumberIntType, &ifType);
 945                         }
 946                         CFRelease(num);
 947                 }
 948
 949                 /*
 950                  * ...and the property we are REALLY interested is in the controller,
 951                  * which is the parent of the interface object.
 952                  */
 953                 (void)IORegistryEntryGetParentEntry(io_interface, kIOServicePlane, &io_controller);
 954                 IOObjectRelease(io_interface);
 955         } else {
 956                 /* if no matching interface */
 957                 return FALSE;
 958         }
 959
 960         if (io_controller) {
 961                 CFNumberRef     num;
 962
 963                 num = IORegistryEntryCreateCFProperty(io_controller, CFSTR(kIOMaxPacketSize), NULL, kNilOptions);
 964                 if (num) {
 965                         if (isA_CFNumber(num)) {
 966                                 int     value;
 967
 968                                 /*
 969                                  * Get the value and subtract the FCS bytes and Ethernet header
 970                                  * sizes from the maximum frame size reported by the controller
 971                                  * to get the MTU size. The 14 byte media header can be found
 972                                  * in the registry, but not the size for the trailing FCS bytes.
 973                                  */
 974                                 CFNumberGetValue(num, kCFNumberIntType, &value);
 975
 976                                 if (ifType == IFT_ETHER) {
 977                                         value -= (ETHER_HDR_LEN + ETHER_CRC_LEN);
 978                                 }
 979
 980                                 if (mtu_min)    *mtu_min = IF_MINMTU;
 981                                 if (mtu_max)    *mtu_max = value;
 982                         }
 983                         CFRelease(num);
 984                 }
 985
 986                 IOObjectRelease(io_controller);
 987         }
 988
 989         return TRUE;
 990 }
 991
 992
 993 Boolean
 994 SCNetworkInterfaceCopyMTU(SCNetworkInterfaceRef interface,
 995                           int                   *mtu_cur,
 996                           int                   *mtu_min,
 997                           int                   *mtu_max)
 998 {
 999         struct ifreq    ifr;
1000         CFStringRef     interfaceName;
1001         Boolean         ok              = FALSE;
1002         int             sock            = -1;
1003
1004         if (!isA_SCNetworkInterface(interface)) {
1005                 _SCErrorSet(kSCStatusInvalidArgument);
1006                 return FALSE;
1007         }
1008
1009         interfaceName = SCNetworkInterfaceGetBSDName(interface);
1010         if (interfaceName == NULL) {
1011                 _SCErrorSet(kSCStatusInvalidArgument);
1012                 return FALSE;
1013         }
1014
1015         bzero((void *)&ifr, sizeof(ifr));
1016         if (_SC_cfstring_to_cstring(interfaceName, ifr.ifr_name, sizeof(ifr.ifr_name), kCFStringEncodingASCII) == NULL) {
1017                 SC_log(LOG_NOTICE, "could not convert interface name");
1018                 _SCErrorSet(kSCStatusInvalidArgument);
1019                 return FALSE;
1020         }
1021
1022         sock = socket(AF_INET, SOCK_DGRAM, 0);
1023         if (sock == -1) {
1024                 _SCErrorSet(errno);
1025                 SC_log(LOG_ERR, "socket() failed: %s", strerror(errno));
1026                 return FALSE;
1027         }
1028
1029         if (ioctl(sock, SIOCGIFMTU, (caddr_t)&ifr) == -1) {
1030                 _SCErrorSet(errno);
1031 //              SC_log(LOG_NOTICE, "ioctl(SIOCGIFMTU) failed: %s", strerror(errno));
1032                 goto done;
1033         }
1034
1035         if (mtu_cur)    *mtu_cur = ifr.ifr_mtu;
1036         if (mtu_min)    *mtu_min = ifr.ifr_mtu;
1037         if (mtu_max)    *mtu_max = ifr.ifr_mtu;
1038
1039         /* get valid MTU range */
1040
1041         if (mtu_min != NULL || mtu_max != NULL) {
1042                 if (ioctl(sock, SIOCGIFDEVMTU, (caddr_t)&ifr) == 0) {
1043                         struct ifdevmtu *       devmtu_p;
1044
1045                         devmtu_p = &ifr.ifr_devmtu;
1046                         if (mtu_min != NULL) {
1047                                 *mtu_min = (devmtu_p->ifdm_min > IF_MINMTU)
1048                                         ? devmtu_p->ifdm_min : IF_MINMTU;
1049                         }
1050                         if (mtu_max != NULL) {
1051                                 *mtu_max = devmtu_p->ifdm_max;
1052                         }
1053                 } else {
1054                         ok = __getIOMTULimits(ifr.ifr_name, mtu_min, mtu_max);
1055                         if (!ok) {
1056                                 CFStringRef     interfaceType;
1057
1058                                 interfaceType = SCNetworkInterfaceGetInterfaceType(interface);
1059                                 if (CFEqual(interfaceType, kSCNetworkInterfaceTypeBridge)) {
1060                                         CFIndex         i;
1061                                         CFArrayRef      members;
1062                                         CFIndex         n;
1063
1064                                         members = SCBridgeInterfaceGetMemberInterfaces(interface);
1065                                         n = (members != NULL) ? CFArrayGetCount(members) : 0;
1066                                         if (n > 1) {
1067                                                 if (mtu_min)    *mtu_min = IF_MINMTU;
1068                                                 if (mtu_max)    *mtu_max = IF_MAXMTU;
1069                                         }
1070                                         for (i = 0; i < n; i++) {
1071                                                 SCNetworkInterfaceRef   member;
1072                                                 int                     member_mtu_min;
1073                                                 int                     member_mtu_max;
1074
1075                                                 member = CFArrayGetValueAtIndex(members, i);
1076                                                 ok = SCNetworkInterfaceCopyMTU(member, NULL, &member_mtu_min, &member_mtu_max);
1077                                                 if (ok) {
1078                                                         if ((mtu_min != NULL) && (*mtu_min < member_mtu_min)) {
1079                                                                 *mtu_min = member_mtu_min;      // min MTU needs to be higher
1080                                                         }
1081                                                         if ((mtu_max != NULL) && (*mtu_max > member_mtu_max)) {
1082                                                                 *mtu_max = member_mtu_max;      // max MTU needs to be lower
1083                                                         }
1084                                                 }
1085                                         }
1086                                 }
1087                         }
1088                 }
1089
1090                 if (mtu_min != NULL) {
1091 #if     IP_MSS > IPV6_MMTU
1092                         if (*mtu_min < IP_MSS) {
1093                                 /* bump up the minimum MTU */
1094                                 *mtu_min = IP_MSS/*576*/;
1095                         }
1096 #else   // IP_MSS > IPV6_MMTU
1097                         if (*mtu_min < IPV6_MMTU) {
1098                                 /* bump up the minimum MTU */
1099                                 *mtu_min = IPV6_MMTU;
1100                         }
1101 #endif  // IP_MSS > IPV6_MMTU
1102
1103                         if ((mtu_cur != NULL) && (*mtu_min > *mtu_cur)) {
1104                                 /* min must be <= cur */
1105                                 *mtu_min = *mtu_cur;
1106                         }
1107
1108                         if ((mtu_max != NULL) && (*mtu_min > *mtu_max)) {
1109                                 /* min must be <= max */
1110                                 *mtu_min = *mtu_max;
1111                         }
1112                 }
1113         }
1114
1115         ok = TRUE;
1116
1117     done :
1118
1119         (void)close(sock);
1120         return ok;
1121 }
1122
1123
1124 Boolean
1125 SCNetworkInterfaceSetMediaOptions(SCNetworkInterfaceRef interface,
1126                                   CFStringRef           subtype,
1127                                   CFArrayRef            options)
1128 {
1129         CFDictionaryRef         configuration;
1130         CFMutableDictionaryRef  newConfiguration        = NULL;
1131         Boolean                 ok                      = FALSE;
1132
1133         if (!isA_SCNetworkInterface(interface)) {
1134                 _SCErrorSet(kSCStatusInvalidArgument);
1135                 return FALSE;
1136         }
1137
1138         configuration = SCNetworkInterfaceGetConfiguration(interface);
1139         if (configuration == NULL) {
1140                 newConfiguration = CFDictionaryCreateMutable(NULL,
1141                                                              0,
1142                                                              &kCFTypeDictionaryKeyCallBacks,
1143                                                              &kCFTypeDictionaryValueCallBacks);
1144         } else {
1145                 newConfiguration = CFDictionaryCreateMutableCopy(NULL, 0, configuration);
1146                 CFDictionaryRemoveValue(newConfiguration, kSCResvInactive);
1147         }
1148
1149         if (subtype != NULL) {
1150                 CFArrayRef      available       = NULL;
1151                 CFArrayRef      config_options  = options;
1152                 CFArrayRef      subtypes        = NULL;
1153                 CFArrayRef      subtype_options = NULL;
1154
1155                 if (options == NULL) {
1156                         config_options = CFArrayCreate(NULL, NULL, 0, &kCFTypeArrayCallBacks);
1157                 }
1158
1159                 if (!SCNetworkInterfaceCopyMediaOptions(interface, NULL, NULL, &available, FALSE)) {
1160                         SC_log(LOG_INFO, "media type / options not available");
1161                         goto checked;
1162                 }
1163
1164                 if (available == NULL) {
1165                         _SCErrorSet(kSCStatusInvalidArgument);
1166                         goto checked;
1167                 }
1168
1169                 subtypes = SCNetworkInterfaceCopyMediaSubTypes(available);
1170                 if ((subtypes == NULL) ||
1171                     !CFArrayContainsValue(subtypes,
1172                                          CFRangeMake(0, CFArrayGetCount(subtypes)),
1173                                          subtype)) {
1174                         SC_log(LOG_INFO, "media type not valid");
1175                         _SCErrorSet(kSCStatusInvalidArgument);
1176                         goto checked;
1177                 }
1178
1179                 subtype_options = SCNetworkInterfaceCopyMediaSubTypeOptions(available, subtype);
1180                 if ((subtype_options == NULL) ||
1181                     !CFArrayContainsValue(subtype_options,
1182                                           CFRangeMake(0, CFArrayGetCount(subtype_options)),
1183                                           config_options)) {
1184                         SC_log(LOG_INFO, "media options not valid for \"%@\"", subtype);
1185                         _SCErrorSet(kSCStatusInvalidArgument);
1186                         goto checked;
1187                 }
1188
1189                 CFDictionarySetValue(newConfiguration, kSCPropNetEthernetMediaSubType, subtype);
1190                 CFDictionarySetValue(newConfiguration,
1191                                      kSCPropNetEthernetMediaOptions,
1192                                      (options != NULL) ? options : config_options);
1193
1194                 ok = TRUE;
1195
1196             checked :
1197
1198                 if (available       != NULL)    CFRelease(available);
1199                 if (subtypes        != NULL)    CFRelease(subtypes);
1200                 if (subtype_options != NULL)    CFRelease(subtype_options);
1201                 if (options         == NULL)    CFRelease(config_options);
1202         } else if (options == NULL) {
1203                 CFDictionaryRemoveValue(newConfiguration, kSCPropNetEthernetMediaSubType);
1204                 CFDictionaryRemoveValue(newConfiguration, kSCPropNetEthernetMediaOptions);
1205                 if (CFDictionaryGetCount(newConfiguration) == 0) {
1206                         CFRelease(newConfiguration);
1207                         newConfiguration = NULL;
1208                 }
1209                 ok = TRUE;
1210         } else {
1211                 SC_log(LOG_INFO, "media type must be specified with options");
1212                 _SCErrorSet(kSCStatusInvalidArgument);
1213         }
1214
1215         if (ok) {
1216                 ok = SCNetworkInterfaceSetConfiguration(interface, newConfiguration);
1217         }
1218
1219         if (newConfiguration != NULL) CFRelease(newConfiguration);
1220         return ok;
1221 }
1222
1223
1224 Boolean
1225 SCNetworkInterfaceSetMTU(SCNetworkInterfaceRef  interface,
1226                          int                    mtu)
1227 {
1228         CFDictionaryRef         configuration;
1229         int                     mtu_max;
1230         int                     mtu_min;
1231         CFMutableDictionaryRef  newConfiguration        = NULL;
1232         Boolean                 ok                      = FALSE;
1233
1234         if (!isA_SCNetworkInterface(interface)) {
1235                 _SCErrorSet(kSCStatusInvalidArgument);
1236                 return FALSE;
1237         }
1238
1239         if (!SCNetworkInterfaceCopyMTU(interface, NULL, &mtu_min, &mtu_max)) {
1240                 SC_log(LOG_INFO, "MTU bounds not available");
1241                 return FALSE;
1242         }
1243
1244         configuration = SCNetworkInterfaceGetConfiguration(interface);
1245         if (configuration == NULL) {
1246                 newConfiguration = CFDictionaryCreateMutable(NULL,
1247                                                              0,
1248                                                              &kCFTypeDictionaryKeyCallBacks,
1249                                                              &kCFTypeDictionaryValueCallBacks);
1250         } else {
1251                 newConfiguration = CFDictionaryCreateMutableCopy(NULL, 0, configuration);
1252                 CFDictionaryRemoveValue(newConfiguration, kSCResvInactive);
1253         }
1254
1255         if ((mtu >= mtu_min) && (mtu <= mtu_max)) {
1256                 CFNumberRef     num;
1257
1258                 num = CFNumberCreate(NULL, kCFNumberIntType, &mtu);
1259                 CFDictionarySetValue(newConfiguration, kSCPropNetEthernetMTU, num);
1260                 CFRelease(num);
1261                 ok = TRUE;
1262         } else if (mtu == 0) {
1263                 CFDictionaryRemoveValue(newConfiguration, kSCPropNetEthernetMTU);
1264                 if (CFDictionaryGetCount(newConfiguration) == 0) {
1265                         CFRelease(newConfiguration);
1266                         newConfiguration = NULL;
1267                 }
1268                 ok = TRUE;
1269         } else {
1270                 SC_log(LOG_INFO, "MTU out of range");
1271                 _SCErrorSet(kSCStatusInvalidArgument);
1272         }
1273
1274         if (ok) {
1275                 ok = SCNetworkInterfaceSetConfiguration(interface, newConfiguration);
1276         }
1277
1278         if (newConfiguration != NULL) CFRelease(newConfiguration);
1279         return ok;
1280 }