bsd/net/if_utun.c

   1 /*
   2  * Copyright (c) 2008-2009 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_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. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29
  30
  31 /* ----------------------------------------------------------------------------------
  32 Application of kernel control for interface creation
  33
  34 Theory of operation:
  35 utun (user tunnel) acts as glue between kernel control sockets and network interfaces.
  36 This kernel control will register an interface for every client that connects.
  37 ---------------------------------------------------------------------------------- */
  38
  39 #include <sys/systm.h>
  40 #include <sys/kern_control.h>
  41 #include <net/kpi_protocol.h>
  42 #include <net/kpi_interface.h>
  43 #include <sys/socket.h>
  44 #include <net/if.h>
  45 #include <net/if_types.h>
  46 #include <net/bpf.h>
  47 #include <net/if_utun.h>
  48 #include <libkern/OSMalloc.h>
  49 #include <libkern/OSAtomic.h>
  50 #include <sys/mbuf.h>
  51 #include <sys/sockio.h>
  52 #include <netinet/in.h>
  53 #include <netinet6/in6_var.h>
  54 #include <netinet6/in6_var.h>
  55 #include <sys/kauth.h>
  56
  57
  58 /* Kernel Control functions */
  59 static errno_t  utun_ctl_connect(kern_ctl_ref kctlref, struct sockaddr_ctl *sac,
  60                                                                  void **unitinfo);
  61 static errno_t  utun_ctl_disconnect(kern_ctl_ref kctlref, u_int32_t unit,
  62                                                                         void *unitinfo);
  63 static errno_t  utun_ctl_send(kern_ctl_ref kctlref, u_int32_t unit,
  64                                                            void *unitinfo, mbuf_t m, int flags);
  65 static errno_t  utun_ctl_getopt(kern_ctl_ref kctlref, u_int32_t unit, void *unitinfo,
  66                                                                  int opt, void *data, size_t *len);
  67 static errno_t  utun_ctl_setopt(kern_ctl_ref kctlref, u_int32_t unit, void *unitinfo,
  68                                                                  int opt, void *data, size_t len);
  69
  70 /* Network Interface functions */
  71 static errno_t  utun_output(ifnet_t interface, mbuf_t data);
  72 static errno_t  utun_demux(ifnet_t interface, mbuf_t data, char *frame_header,
  73                                                    protocol_family_t *protocol);
  74 static errno_t  utun_framer(ifnet_t     interface, mbuf_t *packet,
  75                                                         const struct sockaddr *dest, const char *desk_linkaddr,
  76                                                         const char *frame_type);
  77 static errno_t  utun_add_proto(ifnet_t interface, protocol_family_t protocol,
  78                                                            const struct ifnet_demux_desc *demux_array,
  79                                                            u_int32_t demux_count);
  80 static errno_t  utun_del_proto(ifnet_t interface, protocol_family_t protocol);
  81 static errno_t  utun_ioctl(ifnet_t interface, u_long cmd, void *data);
  82 static void             utun_detached(ifnet_t interface);
  83
  84 /* Protocol handlers */
  85 static errno_t  utun_attach_proto(ifnet_t interface, protocol_family_t proto);
  86 static errno_t  utun_proto_input(ifnet_t interface, protocol_family_t protocol,
  87                                                                  mbuf_t m, char *frame_header);
  88 static errno_t utun_proto_pre_output(ifnet_t interface, protocol_family_t protocol,
  89                                          mbuf_t *packet, const struct sockaddr *dest, void *route,
  90                                          char *frame_type, char *link_layer_dest);
  91
  92 /* Control block allocated for each kernel control connection */
  93 struct utun_pcb {
  94         kern_ctl_ref    utun_ctlref;
  95         ifnet_t                 utun_ifp;
  96         u_int32_t               utun_unit;
  97         u_int32_t               utun_flags;
  98         int                             utun_ext_ifdata_stats;
  99 };
 100
 101 static kern_ctl_ref     utun_kctlref;
 102 static u_int32_t        utun_family;
 103 static OSMallocTag      utun_malloc_tag;
 104 static SInt32           utun_ifcount = 0;
 105
 106 /* Prepend length */
 107 static void*
 108 utun_alloc(size_t size)
 109 {
 110         size_t  *mem = OSMalloc(size + sizeof(size_t), utun_malloc_tag);
 111
 112         if (mem) {
 113                 *mem = size + sizeof(size_t);
 114                 mem++;
 115         }
 116
 117         return (void*)mem;
 118 }
 119
 120 static void
 121 utun_free(void *ptr)
 122 {
 123         size_t  *size = ptr;
 124         size--;
 125         OSFree(size, *size, utun_malloc_tag);
 126 }
 127
 128 errno_t
 129 utun_register_control(void)
 130 {
 131         struct kern_ctl_reg     kern_ctl;
 132         errno_t                         result = 0;
 133
 134         /* Create a tag to allocate memory */
 135         utun_malloc_tag = OSMalloc_Tagalloc(UTUN_CONTROL_NAME, OSMT_DEFAULT);
 136
 137         /* Find a unique value for our interface family */
 138         result = mbuf_tag_id_find(UTUN_CONTROL_NAME, &utun_family);
 139         if (result != 0) {
 140                 printf("utun_register_control - mbuf_tag_id_find_internal failed: %d\n", result);
 141                 return result;
 142         }
 143
 144         bzero(&kern_ctl, sizeof(kern_ctl));
 145         strncpy(kern_ctl.ctl_name, UTUN_CONTROL_NAME, sizeof(kern_ctl.ctl_name));
 146         kern_ctl.ctl_name[sizeof(kern_ctl.ctl_name) - 1] = 0;
 147         kern_ctl.ctl_flags = CTL_FLAG_PRIVILEGED; /* Require root */
 148         kern_ctl.ctl_sendsize = 64 * 1024;
 149         kern_ctl.ctl_recvsize = 64 * 1024;
 150         kern_ctl.ctl_connect = utun_ctl_connect;
 151         kern_ctl.ctl_disconnect = utun_ctl_disconnect;
 152         kern_ctl.ctl_send = utun_ctl_send;
 153         kern_ctl.ctl_setopt = utun_ctl_setopt;
 154         kern_ctl.ctl_getopt = utun_ctl_getopt;
 155
 156         result = ctl_register(&kern_ctl, &utun_kctlref);
 157         if (result != 0) {
 158                 printf("utun_register_control - ctl_register failed: %d\n", result);
 159                 return result;
 160         }
 161
 162         /* Register the protocol plumbers */
 163         if ((result = proto_register_plumber(PF_INET, utun_family,
 164                                                                                  utun_attach_proto, NULL)) != 0) {
 165                 printf("utun_register_control - proto_register_plumber(PF_INET, %d) failed: %d\n",
 166                            utun_family, result);
 167                 ctl_deregister(utun_kctlref);
 168                 return result;
 169         }
 170
 171         /* Register the protocol plumbers */
 172         if ((result = proto_register_plumber(PF_INET6, utun_family,
 173                                                                                  utun_attach_proto, NULL)) != 0) {
 174                 proto_unregister_plumber(PF_INET, utun_family);
 175                 ctl_deregister(utun_kctlref);
 176                 printf("utun_register_control - proto_register_plumber(PF_INET6, %d) failed: %d\n",
 177                            utun_family, result);
 178                 return result;
 179         }
 180
 181         return 0;
 182 }
 183
 184 /* Kernel control functions */
 185
 186 static errno_t
 187 utun_ctl_connect(
 188         kern_ctl_ref            kctlref,
 189         struct sockaddr_ctl     *sac,
 190         void                            **unitinfo)
 191 {
 192         struct ifnet_init_params        utun_init;
 193         struct utun_pcb                         *pcb;
 194         errno_t                                         result;
 195         struct ifnet_stats_param        stats;
 196
 197         /* kernel control allocates, interface frees */
 198         pcb = utun_alloc(sizeof(*pcb));
 199         if (pcb == NULL)
 200                 return ENOMEM;
 201
 202         /* Setup the protocol control block */
 203         bzero(pcb, sizeof(*pcb));
 204         *unitinfo = pcb;
 205         pcb->utun_ctlref = kctlref;
 206         pcb->utun_unit = sac->sc_unit;
 207
 208         printf("utun_ctl_connect: creating interface utun%d\n", pcb->utun_unit - 1);
 209
 210         /* Create the interface */
 211         bzero(&utun_init, sizeof(utun_init));
 212         utun_init.name = "utun";
 213         utun_init.unit = pcb->utun_unit - 1;
 214         utun_init.family = utun_family;
 215         utun_init.type = IFT_OTHER;
 216         utun_init.output = utun_output;
 217         utun_init.demux = utun_demux;
 218         utun_init.framer = utun_framer;
 219         utun_init.add_proto = utun_add_proto;
 220         utun_init.del_proto = utun_del_proto;
 221         utun_init.softc = pcb;
 222         utun_init.ioctl = utun_ioctl;
 223         utun_init.detach = utun_detached;
 224
 225         result = ifnet_allocate(&utun_init, &pcb->utun_ifp);
 226         if (result != 0) {
 227                 printf("utun_ctl_connect - ifnet_allocate failed: %d\n", result);
 228                 utun_free(pcb);
 229                 return result;
 230         }
 231         OSIncrementAtomic(&utun_ifcount);
 232
 233         /* Set flags and additional information. */
 234         ifnet_set_mtu(pcb->utun_ifp, 1500);
 235         ifnet_set_flags(pcb->utun_ifp, IFF_UP | IFF_MULTICAST | IFF_POINTOPOINT, 0xffff);
 236
 237         /* The interface must generate its own IPv6 LinkLocal address,
 238          * if possible following the recommendation of RFC2472 to the 64bit interface ID
 239          */
 240         ifnet_set_eflags(pcb->utun_ifp, IFEF_NOAUTOIPV6LL, IFEF_NOAUTOIPV6LL);
 241
 242         /* Reset the stats in case as the interface may have been recycled */
 243         bzero(&stats, sizeof(struct ifnet_stats_param));
 244         ifnet_set_stat(pcb->utun_ifp, &stats);
 245
 246         /* Attach the interface */
 247         result = ifnet_attach(pcb->utun_ifp, NULL);
 248         if (result != 0) {
 249                 printf("utun_ctl_connect - ifnet_allocate failed: %d\n", result);
 250                 ifnet_release(pcb->utun_ifp);
 251                 utun_free(pcb);
 252         }
 253
 254         /* Attach to bpf */
 255         if (result == 0)
 256                 bpfattach(pcb->utun_ifp, DLT_NULL, 4);
 257
 258         /* The interfaces resoures allocated, mark it as running */
 259         if (result == 0)
 260                 ifnet_set_flags(pcb->utun_ifp, IFF_RUNNING, IFF_RUNNING);
 261
 262         return result;
 263 }
 264
 265 static errno_t
 266 utun_detach_ip(
 267         ifnet_t                         interface,
 268         protocol_family_t       protocol,
 269         socket_t                        pf_socket)
 270 {
 271         errno_t result = EPROTONOSUPPORT;
 272
 273         /* Attempt a detach */
 274         if (protocol == PF_INET) {
 275                 struct ifreq    ifr;
 276
 277                 bzero(&ifr, sizeof(ifr));
 278                 snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d",
 279                                  ifnet_name(interface), ifnet_unit(interface));
 280
 281                 result = sock_ioctl(pf_socket, SIOCPROTODETACH, &ifr);
 282         }
 283         else if (protocol == PF_INET6) {
 284                 struct in6_ifreq        ifr6;
 285
 286                 bzero(&ifr6, sizeof(ifr6));
 287                 snprintf(ifr6.ifr_name, sizeof(ifr6.ifr_name), "%s%d",
 288                                  ifnet_name(interface), ifnet_unit(interface));
 289
 290                 result = sock_ioctl(pf_socket, SIOCPROTODETACH_IN6, &ifr6);
 291         }
 292
 293         return result;
 294 }
 295
 296 static void
 297 utun_remove_address(
 298         ifnet_t                         interface,
 299         protocol_family_t       protocol,
 300         ifaddr_t                        address,
 301         socket_t                        pf_socket)
 302 {
 303         errno_t result = 0;
 304
 305         /* Attempt a detach */
 306         if (protocol == PF_INET) {
 307                 struct ifreq    ifr;
 308
 309                 bzero(&ifr, sizeof(ifr));
 310                 snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d",
 311                                  ifnet_name(interface), ifnet_unit(interface));
 312                 result = ifaddr_address(address, &ifr.ifr_addr, sizeof(ifr.ifr_addr));
 313                 if (result != 0) {
 314                         printf("utun_remove_address - ifaddr_address failed: %d", result);
 315                 }
 316                 else {
 317                         result = sock_ioctl(pf_socket, SIOCDIFADDR, &ifr);
 318                         if (result != 0) {
 319                                 printf("utun_remove_address - SIOCDIFADDR failed: %d", result);
 320                         }
 321                 }
 322         }
 323         else if (protocol == PF_INET6) {
 324                 struct in6_ifreq        ifr6;
 325
 326                 bzero(&ifr6, sizeof(ifr6));
 327                 snprintf(ifr6.ifr_name, sizeof(ifr6.ifr_name), "%s%d",
 328                                  ifnet_name(interface), ifnet_unit(interface));
 329                 result = ifaddr_address(address, (struct sockaddr*)&ifr6.ifr_addr,
 330                                                                 sizeof(ifr6.ifr_addr));
 331                 if (result != 0) {
 332                         printf("utun_remove_address - ifaddr_address failed (v6): %d",
 333                                    result);
 334                 }
 335                 else {
 336                         result = sock_ioctl(pf_socket, SIOCDIFADDR_IN6, &ifr6);
 337                         if (result != 0) {
 338                                 printf("utun_remove_address - SIOCDIFADDR_IN6 failed: %d",
 339                                            result);
 340                         }
 341                 }
 342         }
 343 }
 344
 345 static void
 346 utun_cleanup_family(
 347         ifnet_t                         interface,
 348         protocol_family_t       protocol)
 349 {
 350         errno_t         result = 0;
 351         socket_t        pf_socket = NULL;
 352         ifaddr_t        *addresses = NULL;
 353         int                     i;
 354
 355         if (protocol != PF_INET && protocol != PF_INET6) {
 356                 printf("utun_cleanup_family - invalid protocol family %d\n", protocol);
 357                 return;
 358         }
 359
 360         /* Create a socket for removing addresses and detaching the protocol */
 361         result = sock_socket(protocol, SOCK_DGRAM, 0, NULL, NULL, &pf_socket);
 362         if (result != 0) {
 363                 if (result != EAFNOSUPPORT)
 364                         printf("utun_cleanup_family - failed to create %s socket: %d\n",
 365                                 protocol == PF_INET ? "IP" : "IPv6", result);
 366                 goto cleanup;
 367         }
 368
 369         result = utun_detach_ip(interface, protocol, pf_socket);
 370         if (result == 0 || result == ENXIO) {
 371                 /* We are done! We either detached or weren't attached. */
 372                 goto cleanup;
 373         }
 374         else if (result != EBUSY) {
 375                 /* Uh, not really sure what happened here... */
 376                 printf("utun_cleanup_family - utun_detach_ip failed: %d\n", result);
 377                 goto cleanup;
 378         }
 379
 380         /*
 381          * At this point, we received an EBUSY error. This means there are
 382          * addresses attached. We should detach them and then try again.
 383          */
 384         result = ifnet_get_address_list_family(interface, &addresses, protocol);
 385         if (result != 0) {
 386                 printf("fnet_get_address_list_family(%s%d, 0xblah, %s) - failed: %d\n",
 387                         ifnet_name(interface), ifnet_unit(interface),
 388                         protocol == PF_INET ? "PF_INET" : "PF_INET6", result);
 389                 goto cleanup;
 390         }
 391
 392         for (i = 0; addresses[i] != 0; i++) {
 393                 utun_remove_address(interface, protocol, addresses[i], pf_socket);
 394         }
 395         ifnet_free_address_list(addresses);
 396         addresses = NULL;
 397
 398         /*
 399          * The addresses should be gone, we should try the remove again.
 400          */
 401         result = utun_detach_ip(interface, protocol, pf_socket);
 402         if (result != 0 && result != ENXIO) {
 403                 printf("utun_cleanup_family - utun_detach_ip failed: %d\n", result);
 404         }
 405
 406 cleanup:
 407         if (pf_socket != NULL)
 408                 sock_close(pf_socket);
 409
 410         if (addresses != NULL)
 411                 ifnet_free_address_list(addresses);
 412 }
 413
 414 static errno_t
 415 utun_ctl_disconnect(
 416         __unused kern_ctl_ref   kctlref,
 417         __unused u_int32_t              unit,
 418         void                                    *unitinfo)
 419 {
 420         struct utun_pcb *pcb = unitinfo;
 421         ifnet_t                 ifp = pcb->utun_ifp;
 422         errno_t                 result = 0;
 423
 424         pcb->utun_ctlref = NULL;
 425         pcb->utun_unit = 0;
 426
 427         /*
 428          * We want to do everything in our power to ensure that the interface
 429          * really goes away when the socket is closed. We must remove IP/IPv6
 430          * addresses and detach the protocols. Finally, we can remove and
 431          * release the interface.
 432          */
 433         utun_cleanup_family(ifp, AF_INET);
 434         utun_cleanup_family(ifp, AF_INET6);
 435
 436         if ((result = ifnet_detach(ifp)) != 0) {
 437                 printf("utun_ctl_disconnect - ifnet_detach failed: %d\n", result);
 438         }
 439
 440         if ((result = ifnet_release(ifp)) != 0) {
 441                 printf("utun_ctl_disconnect - ifnet_release failed: %d\n", result);
 442         }
 443
 444         return 0;
 445 }
 446
 447 static errno_t
 448 utun_ctl_send(
 449         __unused kern_ctl_ref   kctlref,
 450         __unused u_int32_t              unit,
 451         void                                    *unitinfo,
 452         mbuf_t                                  m,
 453         __unused int                    flags)
 454 {
 455         struct utun_pcb                                         *pcb = unitinfo;
 456         errno_t                                                         result;
 457
 458         mbuf_pkthdr_setrcvif(m, pcb->utun_ifp);
 459
 460         bpf_tap_in(pcb->utun_ifp, DLT_NULL, m, 0, 0);
 461
 462         if (pcb->utun_flags & UTUN_FLAGS_NO_INPUT) {
 463                 /* flush data */
 464                 mbuf_freem(m);
 465                 return 0;
 466         }
 467
 468         if (!pcb->utun_ext_ifdata_stats) {
 469                 struct ifnet_stat_increment_param       incs;
 470
 471                 bzero(&incs, sizeof(incs));
 472                 incs.packets_in = 1;
 473                 incs.bytes_in = mbuf_pkthdr_len(m);
 474                 result = ifnet_input(pcb->utun_ifp, m, &incs);
 475         } else {
 476                 result = ifnet_input(pcb->utun_ifp, m, NULL);
 477         }
 478         if (result != 0) {
 479                 ifnet_stat_increment_in(pcb->utun_ifp, 0, 0, 1);
 480
 481                 printf("utun_ctl_send - ifnet_input failed: %d\n", result);
 482                 mbuf_freem(m);
 483         }
 484
 485         return 0;
 486 }
 487
 488 static errno_t
 489 utun_ctl_setopt(
 490         __unused kern_ctl_ref   kctlref,
 491         __unused u_int32_t              unit,
 492         void                                    *unitinfo,
 493         int                                             opt,
 494         void                                    *data,
 495         size_t                                  len)
 496 {
 497         struct utun_pcb                 *pcb = unitinfo;
 498         errno_t                                 result = 0;
 499
 500         /* check for privileges for privileged options */
 501         switch (opt) {
 502                 case UTUN_OPT_FLAGS:
 503                 case UTUN_OPT_EXT_IFDATA_STATS:
 504                         if (kauth_cred_issuser(kauth_cred_get()) == 0) {
 505                                 return EPERM;
 506                         }
 507                         break;
 508         }
 509
 510         switch (opt) {
 511                 case UTUN_OPT_FLAGS:
 512                         if (len != sizeof(u_int32_t))
 513                                 result = EMSGSIZE;
 514                         else
 515                                 pcb->utun_flags = *(u_int32_t *)data;
 516                         break;
 517
 518                 case UTUN_OPT_EXT_IFDATA_STATS:
 519                         if (len != sizeof(int)) {
 520                                 result = EMSGSIZE;
 521                                 break;
 522                         }
 523                         pcb->utun_ext_ifdata_stats = (*(int *)data) ? 1 : 0;
 524                         break;
 525
 526                 case UTUN_OPT_INC_IFDATA_STATS_IN:
 527                 case UTUN_OPT_INC_IFDATA_STATS_OUT: {
 528                         struct utun_stats_param *utsp = (struct utun_stats_param *)data;
 529
 530                         if (utsp == NULL || len < sizeof(struct utun_stats_param)) {
 531                                 result = EINVAL;
 532                                 break;
 533                         }
 534                         if (!pcb->utun_ext_ifdata_stats) {
 535                                 result = EINVAL;
 536                                 break;
 537                         }
 538                         if (opt == UTUN_OPT_INC_IFDATA_STATS_IN)
 539                                 ifnet_stat_increment_in(pcb->utun_ifp, utsp->utsp_packets,
 540                                         utsp->utsp_bytes, utsp->utsp_errors);
 541                         else
 542                                 ifnet_stat_increment_out(pcb->utun_ifp, utsp->utsp_packets,
 543                                         utsp->utsp_bytes, utsp->utsp_errors);
 544                         break;
 545                 }
 546
 547                 default:
 548                         result = ENOPROTOOPT;
 549                         break;
 550         }
 551
 552         return result;
 553 }
 554
 555 static errno_t
 556 utun_ctl_getopt(
 557         __unused kern_ctl_ref   kctlref,
 558         __unused u_int32_t              unit,
 559         void                                    *unitinfo,
 560         int                                             opt,
 561         void                                    *data,
 562         size_t                                  *len)
 563 {
 564         struct utun_pcb                 *pcb = unitinfo;
 565         errno_t                                 result = 0;
 566
 567         switch (opt) {
 568                 case UTUN_OPT_FLAGS:
 569                         if (*len != sizeof(u_int32_t))
 570                                 result = EMSGSIZE;
 571                         else
 572                                 *(u_int32_t *)data = pcb->utun_flags;
 573                         break;
 574
 575                 case UTUN_OPT_EXT_IFDATA_STATS:
 576                         if (*len != sizeof(int))
 577                                 result = EMSGSIZE;
 578                         else
 579                                 *(int *)data = (pcb->utun_ext_ifdata_stats) ? 1 : 0;
 580                         break;
 581
 582                 case UTUN_OPT_IFNAME:
 583                         *len = snprintf(data, *len, "%s%d", ifnet_name(pcb->utun_ifp), ifnet_unit(pcb->utun_ifp)) + 1;
 584                         break;
 585
 586                 default:
 587                         result = ENOPROTOOPT;
 588                         break;
 589         }
 590
 591         return result;
 592 }
 593
 594 /* Network Interface functions */
 595 static errno_t
 596 utun_output(
 597                            ifnet_t      interface,
 598                            mbuf_t       data)
 599 {
 600         struct utun_pcb *pcb = ifnet_softc(interface);
 601         errno_t                 result;
 602
 603         bpf_tap_out(pcb->utun_ifp, DLT_NULL, data, 0, 0);
 604
 605         if (pcb->utun_flags & UTUN_FLAGS_NO_OUTPUT) {
 606                 /* flush data */
 607                 mbuf_freem(data);
 608                 return 0;
 609         }
 610
 611         if (pcb->utun_ctlref) {
 612                 int     length = mbuf_pkthdr_len(data);
 613                 result = ctl_enqueuembuf(pcb->utun_ctlref, pcb->utun_unit, data, CTL_DATA_EOR);
 614                 if (result != 0) {
 615                         mbuf_freem(data);
 616                         printf("utun_output - ctl_enqueuembuf failed: %d\n", result);
 617
 618                         ifnet_stat_increment_out(interface, 0, 0, 1);
 619                 }
 620                 else {
 621                         if (!pcb->utun_ext_ifdata_stats)
 622                                 ifnet_stat_increment_out(interface, 1, length, 0);
 623                 }
 624         }
 625         else
 626                 mbuf_freem(data);
 627
 628         return 0;
 629 }
 630
 631 /* Network Interface functions */
 632 static errno_t
 633 utun_demux(
 634         __unused ifnet_t        interface,
 635         mbuf_t                          data,
 636         __unused char           *frame_header,
 637         protocol_family_t       *protocol)
 638 {
 639
 640         while (data != NULL && mbuf_len(data) < 1) {
 641                 data = mbuf_next(data);
 642         }
 643
 644         if (data == NULL)
 645                 return ENOENT;
 646
 647         *protocol = ntohl(*(u_int32_t *)mbuf_data(data));
 648         return 0;
 649 }
 650
 651 static errno_t
 652 utun_framer(
 653                    __unused ifnet_t                             interface,
 654                    mbuf_t                               *packet,
 655                         __unused const struct sockaddr *dest,
 656                         __unused const char *desk_linkaddr,
 657                         const char *frame_type)
 658 {
 659     if (mbuf_prepend(packet, sizeof(protocol_family_t), MBUF_DONTWAIT) != 0) {
 660                 printf("utun_framer - ifnet_output prepend failed\n");
 661
 662                 ifnet_stat_increment_out(interface, 0, 0, 1);
 663
 664                 // just return, because the buffer was freed in mbuf_prepend
 665         return EJUSTRETURN;
 666     }
 667
 668     // place protocol number at the beginning of the mbuf
 669     *(protocol_family_t *)mbuf_data(*packet) = htonl(*(protocol_family_t *)(uintptr_t)(size_t)frame_type);
 670
 671     return 0;
 672 }
 673
 674 static errno_t
 675 utun_add_proto(
 676         __unused ifnet_t                                                interface,
 677         protocol_family_t                                               protocol,
 678         __unused const struct ifnet_demux_desc  *demux_array,
 679         __unused u_int32_t                                              demux_count)
 680 {
 681         switch(protocol) {
 682                 case PF_INET:
 683                         return 0;
 684                 case PF_INET6:
 685                         return 0;
 686                 default:
 687                         break;
 688         }
 689
 690         return ENOPROTOOPT;
 691 }
 692
 693 static errno_t
 694 utun_del_proto(
 695         __unused ifnet_t                        interface,
 696         __unused protocol_family_t      protocol)
 697 {
 698         return 0;
 699 }
 700
 701 static errno_t
 702 utun_ioctl(
 703         ifnet_t         interface,
 704         u_long          command,
 705         void            *data)
 706 {
 707         errno_t result = 0;
 708         struct ifaddr   *ifa = (struct ifaddr *)data;
 709
 710         switch(command) {
 711                 case SIOCSIFMTU:
 712                         ifnet_set_mtu(interface, ((struct ifreq*)data)->ifr_mtu);
 713                         break;
 714
 715                 case SIOCSIFFLAGS:
 716                         /* ifioctl() takes care of it */
 717                         break;
 718
 719                 case SIOCSIFADDR:
 720                 case SIOCAIFADDR:
 721                         /* This will be called for called for IPv6 Address additions */
 722                         if (ifa->ifa_addr->sa_family == AF_INET6)
 723                                 break;
 724                         /* Fall though for other families like IPv4 */
 725
 726                 default:
 727                         result = EOPNOTSUPP;
 728         }
 729
 730         return result;
 731 }
 732
 733 static void
 734 utun_detached(
 735         ifnet_t interface)
 736 {
 737         struct utun_pcb *pcb = ifnet_softc(interface);
 738
 739         utun_free(pcb);
 740
 741         OSDecrementAtomic(&utun_ifcount);
 742 }
 743
 744 /* Protocol Handlers */
 745
 746 static errno_t
 747 utun_proto_input(
 748         __unused ifnet_t        interface,
 749         protocol_family_t       protocol,
 750         mbuf_t                          m,
 751         __unused char           *frame_header)
 752 {
 753
 754         // remove protocol family first
 755         mbuf_adj(m, sizeof(u_int32_t));
 756
 757         proto_input(protocol, m);
 758
 759         return 0;
 760 }
 761
 762 static errno_t
 763 utun_proto_pre_output(
 764         __unused ifnet_t        interface,
 765         protocol_family_t       protocol,
 766         __unused mbuf_t         *packet,
 767         __unused const struct sockaddr *dest,
 768         __unused void *route,
 769         __unused char *frame_type,
 770         __unused char *link_layer_dest)
 771 {
 772
 773     *(protocol_family_t *)(void *)frame_type = protocol;
 774         return 0;
 775 }
 776
 777 static errno_t
 778 utun_attach_proto(
 779         ifnet_t                         interface,
 780         protocol_family_t       protocol)
 781 {
 782         struct ifnet_attach_proto_param proto;
 783         errno_t                                                 result;
 784
 785         bzero(&proto, sizeof(proto));
 786         proto.input = utun_proto_input;
 787         proto.pre_output = utun_proto_pre_output;
 788
 789         result = ifnet_attach_protocol(interface, protocol, &proto);
 790         if (result != 0 && result != EEXIST) {
 791                 printf("utun_attach_inet - ifnet_attach_protocol %d failed: %d\n",
 792                         protocol, result);
 793         }
 794
 795         return result;
 796 }
 797