bsd/net/if_utun.c

   1 /*
   2  * Copyright (c) 2008-2014 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 static void             utun_ctl_rcvd(kern_ctl_ref kctlref, u_int32_t unit, void *unitinfo,
  70                                                                 int flags);
  71
  72 /* Network Interface functions */
  73 static void     utun_start(ifnet_t interface);
  74 static errno_t  utun_output(ifnet_t interface, mbuf_t data);
  75 static errno_t  utun_demux(ifnet_t interface, mbuf_t data, char *frame_header,
  76                                                    protocol_family_t *protocol);
  77 static errno_t  utun_framer(ifnet_t interface, mbuf_t *packet,
  78     const struct sockaddr *dest, const char *desk_linkaddr,
  79     const char *frame_type, u_int32_t *prepend_len, u_int32_t *postpend_len);
  80 static errno_t  utun_add_proto(ifnet_t interface, protocol_family_t protocol,
  81                                                            const struct ifnet_demux_desc *demux_array,
  82                                                            u_int32_t demux_count);
  83 static errno_t  utun_del_proto(ifnet_t interface, protocol_family_t protocol);
  84 static errno_t  utun_ioctl(ifnet_t interface, u_long cmd, void *data);
  85 static void             utun_detached(ifnet_t interface);
  86
  87 /* Protocol handlers */
  88 static errno_t  utun_attach_proto(ifnet_t interface, protocol_family_t proto);
  89 static errno_t  utun_proto_input(ifnet_t interface, protocol_family_t protocol,
  90                                                                  mbuf_t m, char *frame_header);
  91 static errno_t utun_proto_pre_output(ifnet_t interface, protocol_family_t protocol,
  92                                          mbuf_t *packet, const struct sockaddr *dest, void *route,
  93                                          char *frame_type, char *link_layer_dest);
  94 __private_extern__ errno_t utun_pkt_input (struct utun_pcb *pcb, mbuf_t m);
  95
  96 static kern_ctl_ref     utun_kctlref;
  97 static u_int32_t        utun_family;
  98 static OSMallocTag      utun_malloc_tag;
  99 static SInt32           utun_ifcount = 0;
 100
 101 /* Prepend length */
 102 void*
 103 utun_alloc(size_t size)
 104 {
 105         size_t  *mem = OSMalloc(size + sizeof(size_t), utun_malloc_tag);
 106
 107         if (mem) {
 108                 *mem = size + sizeof(size_t);
 109                 mem++;
 110         }
 111
 112         return (void*)mem;
 113 }
 114
 115 void
 116 utun_free(void *ptr)
 117 {
 118         size_t  *size = ptr;
 119         size--;
 120         OSFree(size, *size, utun_malloc_tag);
 121 }
 122
 123 errno_t
 124 utun_register_control(void)
 125 {
 126         struct kern_ctl_reg     kern_ctl;
 127         errno_t                         result = 0;
 128
 129         /* Create a tag to allocate memory */
 130         utun_malloc_tag = OSMalloc_Tagalloc(UTUN_CONTROL_NAME, OSMT_DEFAULT);
 131
 132         /* Find a unique value for our interface family */
 133         result = mbuf_tag_id_find(UTUN_CONTROL_NAME, &utun_family);
 134         if (result != 0) {
 135                 printf("utun_register_control - mbuf_tag_id_find_internal failed: %d\n", result);
 136                 return result;
 137         }
 138
 139         bzero(&kern_ctl, sizeof(kern_ctl));
 140         strlcpy(kern_ctl.ctl_name, UTUN_CONTROL_NAME, sizeof(kern_ctl.ctl_name));
 141         kern_ctl.ctl_name[sizeof(kern_ctl.ctl_name) - 1] = 0;
 142         kern_ctl.ctl_flags = CTL_FLAG_PRIVILEGED | CTL_FLAG_REG_EXTENDED; /* Require root */
 143         kern_ctl.ctl_sendsize = 512 * 1024;
 144         kern_ctl.ctl_recvsize = 512 * 1024;
 145         kern_ctl.ctl_connect = utun_ctl_connect;
 146         kern_ctl.ctl_disconnect = utun_ctl_disconnect;
 147         kern_ctl.ctl_send = utun_ctl_send;
 148         kern_ctl.ctl_setopt = utun_ctl_setopt;
 149         kern_ctl.ctl_getopt = utun_ctl_getopt;
 150         kern_ctl.ctl_rcvd = utun_ctl_rcvd;
 151
 152         utun_ctl_init_crypto();
 153
 154         result = ctl_register(&kern_ctl, &utun_kctlref);
 155         if (result != 0) {
 156                 printf("utun_register_control - ctl_register failed: %d\n", result);
 157                 return result;
 158         }
 159
 160         /* Register the protocol plumbers */
 161         if ((result = proto_register_plumber(PF_INET, utun_family,
 162                                                                                  utun_attach_proto, NULL)) != 0) {
 163                 printf("utun_register_control - proto_register_plumber(PF_INET, %d) failed: %d\n",
 164                            utun_family, result);
 165                 ctl_deregister(utun_kctlref);
 166                 return result;
 167         }
 168
 169         /* Register the protocol plumbers */
 170         if ((result = proto_register_plumber(PF_INET6, utun_family,
 171                                                                                  utun_attach_proto, NULL)) != 0) {
 172                 proto_unregister_plumber(PF_INET, utun_family);
 173                 ctl_deregister(utun_kctlref);
 174                 printf("utun_register_control - proto_register_plumber(PF_INET6, %d) failed: %d\n",
 175                            utun_family, result);
 176                 return result;
 177         }
 178
 179         return 0;
 180 }
 181
 182 /* Kernel control functions */
 183
 184 static errno_t
 185 utun_ctl_connect(
 186         kern_ctl_ref            kctlref,
 187         struct sockaddr_ctl     *sac,
 188         void                            **unitinfo)
 189 {
 190         struct ifnet_init_eparams       utun_init;
 191         struct utun_pcb                         *pcb;
 192         errno_t                                         result;
 193         struct ifnet_stats_param        stats;
 194
 195         /* kernel control allocates, interface frees */
 196         pcb = utun_alloc(sizeof(*pcb));
 197         if (pcb == NULL)
 198                 return ENOMEM;
 199
 200         /* Setup the protocol control block */
 201         bzero(pcb, sizeof(*pcb));
 202         *unitinfo = pcb;
 203         pcb->utun_ctlref = kctlref;
 204         pcb->utun_unit = sac->sc_unit;
 205         pcb->utun_pending_packets = 0;
 206         pcb->utun_max_pending_packets = 1;
 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.ver = IFNET_INIT_CURRENT_VERSION;
 213         utun_init.len = sizeof (utun_init);
 214         utun_init.name = "utun";
 215         utun_init.start = utun_start;
 216         utun_init.unit = pcb->utun_unit - 1;
 217         utun_init.family = utun_family;
 218         utun_init.type = IFT_OTHER;
 219         utun_init.demux = utun_demux;
 220         utun_init.framer_extended = utun_framer;
 221         utun_init.add_proto = utun_add_proto;
 222         utun_init.del_proto = utun_del_proto;
 223         utun_init.softc = pcb;
 224         utun_init.ioctl = utun_ioctl;
 225         utun_init.detach = utun_detached;
 226
 227         result = ifnet_allocate_extended(&utun_init, &pcb->utun_ifp);
 228         if (result != 0) {
 229                 printf("utun_ctl_connect - ifnet_allocate failed: %d\n", result);
 230                 utun_free(pcb);
 231                 return result;
 232         }
 233         OSIncrementAtomic(&utun_ifcount);
 234
 235         /* Set flags and additional information. */
 236         ifnet_set_mtu(pcb->utun_ifp, 1500);
 237         ifnet_set_flags(pcb->utun_ifp, IFF_UP | IFF_MULTICAST | IFF_POINTOPOINT, 0xffff);
 238
 239         /* The interface must generate its own IPv6 LinkLocal address,
 240          * if possible following the recommendation of RFC2472 to the 64bit interface ID
 241          */
 242         ifnet_set_eflags(pcb->utun_ifp, IFEF_NOAUTOIPV6LL, IFEF_NOAUTOIPV6LL);
 243
 244         /* Reset the stats in case as the interface may have been recycled */
 245         bzero(&stats, sizeof(struct ifnet_stats_param));
 246         ifnet_set_stat(pcb->utun_ifp, &stats);
 247
 248         /* Attach the interface */
 249         result = ifnet_attach(pcb->utun_ifp, NULL);
 250         if (result != 0) {
 251                 printf("utun_ctl_connect - ifnet_allocate failed: %d\n", result);
 252                 ifnet_release(pcb->utun_ifp);
 253                 utun_free(pcb);
 254         }
 255
 256         /* Attach to bpf */
 257         if (result == 0)
 258                 bpfattach(pcb->utun_ifp, DLT_NULL, 4);
 259
 260         /* The interfaces resoures allocated, mark it as running */
 261         if (result == 0)
 262                 ifnet_set_flags(pcb->utun_ifp, IFF_RUNNING, IFF_RUNNING);
 263
 264         return result;
 265 }
 266
 267 static errno_t
 268 utun_detach_ip(
 269         ifnet_t                         interface,
 270         protocol_family_t       protocol,
 271         socket_t                        pf_socket)
 272 {
 273         errno_t result = EPROTONOSUPPORT;
 274
 275         /* Attempt a detach */
 276         if (protocol == PF_INET) {
 277                 struct ifreq    ifr;
 278
 279                 bzero(&ifr, sizeof(ifr));
 280                 snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d",
 281                                  ifnet_name(interface), ifnet_unit(interface));
 282
 283                 result = sock_ioctl(pf_socket, SIOCPROTODETACH, &ifr);
 284         }
 285         else if (protocol == PF_INET6) {
 286                 struct in6_ifreq        ifr6;
 287
 288                 bzero(&ifr6, sizeof(ifr6));
 289                 snprintf(ifr6.ifr_name, sizeof(ifr6.ifr_name), "%s%d",
 290                                  ifnet_name(interface), ifnet_unit(interface));
 291
 292                 result = sock_ioctl(pf_socket, SIOCPROTODETACH_IN6, &ifr6);
 293         }
 294
 295         return result;
 296 }
 297
 298 static void
 299 utun_remove_address(
 300         ifnet_t                         interface,
 301         protocol_family_t       protocol,
 302         ifaddr_t                        address,
 303         socket_t                        pf_socket)
 304 {
 305         errno_t result = 0;
 306
 307         /* Attempt a detach */
 308         if (protocol == PF_INET) {
 309                 struct ifreq    ifr;
 310
 311                 bzero(&ifr, sizeof(ifr));
 312                 snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d",
 313                                  ifnet_name(interface), ifnet_unit(interface));
 314                 result = ifaddr_address(address, &ifr.ifr_addr, sizeof(ifr.ifr_addr));
 315                 if (result != 0) {
 316                         printf("utun_remove_address - ifaddr_address failed: %d", result);
 317                 }
 318                 else {
 319                         result = sock_ioctl(pf_socket, SIOCDIFADDR, &ifr);
 320                         if (result != 0) {
 321                                 printf("utun_remove_address - SIOCDIFADDR failed: %d", result);
 322                         }
 323                 }
 324         }
 325         else if (protocol == PF_INET6) {
 326                 struct in6_ifreq        ifr6;
 327
 328                 bzero(&ifr6, sizeof(ifr6));
 329                 snprintf(ifr6.ifr_name, sizeof(ifr6.ifr_name), "%s%d",
 330                                  ifnet_name(interface), ifnet_unit(interface));
 331                 result = ifaddr_address(address, (struct sockaddr*)&ifr6.ifr_addr,
 332                                                                 sizeof(ifr6.ifr_addr));
 333                 if (result != 0) {
 334                         printf("utun_remove_address - ifaddr_address failed (v6): %d",
 335                                    result);
 336                 }
 337                 else {
 338                         result = sock_ioctl(pf_socket, SIOCDIFADDR_IN6, &ifr6);
 339                         if (result != 0) {
 340                                 printf("utun_remove_address - SIOCDIFADDR_IN6 failed: %d",
 341                                            result);
 342                         }
 343                 }
 344         }
 345 }
 346
 347 static void
 348 utun_cleanup_family(
 349         ifnet_t                         interface,
 350         protocol_family_t       protocol)
 351 {
 352         errno_t         result = 0;
 353         socket_t        pf_socket = NULL;
 354         ifaddr_t        *addresses = NULL;
 355         int                     i;
 356
 357         if (protocol != PF_INET && protocol != PF_INET6) {
 358                 printf("utun_cleanup_family - invalid protocol family %d\n", protocol);
 359                 return;
 360         }
 361
 362         /* Create a socket for removing addresses and detaching the protocol */
 363         result = sock_socket(protocol, SOCK_DGRAM, 0, NULL, NULL, &pf_socket);
 364         if (result != 0) {
 365                 if (result != EAFNOSUPPORT)
 366                         printf("utun_cleanup_family - failed to create %s socket: %d\n",
 367                                 protocol == PF_INET ? "IP" : "IPv6", result);
 368                 goto cleanup;
 369         }
 370
 371         /* always set SS_PRIV, we want to close and detach regardless */
 372         sock_setpriv(pf_socket, 1);
 373
 374         result = utun_detach_ip(interface, protocol, pf_socket);
 375         if (result == 0 || result == ENXIO) {
 376                 /* We are done! We either detached or weren't attached. */
 377                 goto cleanup;
 378         }
 379         else if (result != EBUSY) {
 380                 /* Uh, not really sure what happened here... */
 381                 printf("utun_cleanup_family - utun_detach_ip failed: %d\n", result);
 382                 goto cleanup;
 383         }
 384
 385         /*
 386          * At this point, we received an EBUSY error. This means there are
 387          * addresses attached. We should detach them and then try again.
 388          */
 389         result = ifnet_get_address_list_family(interface, &addresses, protocol);
 390         if (result != 0) {
 391                 printf("fnet_get_address_list_family(%s%d, 0xblah, %s) - failed: %d\n",
 392                         ifnet_name(interface), ifnet_unit(interface),
 393                         protocol == PF_INET ? "PF_INET" : "PF_INET6", result);
 394                 goto cleanup;
 395         }
 396
 397         for (i = 0; addresses[i] != 0; i++) {
 398                 utun_remove_address(interface, protocol, addresses[i], pf_socket);
 399         }
 400         ifnet_free_address_list(addresses);
 401         addresses = NULL;
 402
 403         /*
 404          * The addresses should be gone, we should try the remove again.
 405          */
 406         result = utun_detach_ip(interface, protocol, pf_socket);
 407         if (result != 0 && result != ENXIO) {
 408                 printf("utun_cleanup_family - utun_detach_ip failed: %d\n", result);
 409         }
 410
 411 cleanup:
 412         if (pf_socket != NULL)
 413                 sock_close(pf_socket);
 414
 415         if (addresses != NULL)
 416                 ifnet_free_address_list(addresses);
 417 }
 418
 419 static errno_t
 420 utun_ctl_disconnect(
 421         __unused kern_ctl_ref   kctlref,
 422         __unused u_int32_t              unit,
 423         void                                    *unitinfo)
 424 {
 425         struct utun_pcb *pcb = unitinfo;
 426         ifnet_t                 ifp = pcb->utun_ifp;
 427         errno_t                 result = 0;
 428
 429         utun_cleanup_crypto(pcb);
 430
 431         pcb->utun_ctlref = NULL;
 432         pcb->utun_unit = 0;
 433
 434         /*
 435          * We want to do everything in our power to ensure that the interface
 436          * really goes away when the socket is closed. We must remove IP/IPv6
 437          * addresses and detach the protocols. Finally, we can remove and
 438          * release the interface.
 439          */
 440         utun_cleanup_family(ifp, AF_INET);
 441         utun_cleanup_family(ifp, AF_INET6);
 442
 443         if ((result = ifnet_detach(ifp)) != 0) {
 444                 printf("utun_ctl_disconnect - ifnet_detach failed: %d\n", result);
 445         }
 446
 447         if ((result = ifnet_release(ifp)) != 0) {
 448                 printf("utun_ctl_disconnect - ifnet_release failed: %d\n", result);
 449         }
 450
 451         return 0;
 452 }
 453
 454 static errno_t
 455 utun_ctl_send(
 456         __unused kern_ctl_ref   kctlref,
 457         __unused u_int32_t              unit,
 458         void                                    *unitinfo,
 459         mbuf_t                                  m,
 460         __unused int                    flags)
 461 {
 462         /*
 463          * The userland ABI requires the first four bytes have the protocol family
 464          * in network byte order: swap them
 465          */
 466         if (m_pktlen(m) >= 4)
 467                 *(protocol_family_t *)mbuf_data(m) = ntohl(*(protocol_family_t *)mbuf_data(m));
 468         else
 469                 printf("%s - unexpected short mbuf pkt len %d\n", __func__, m_pktlen(m) );
 470
 471         return utun_pkt_input((struct utun_pcb *)unitinfo, m);
 472 }
 473
 474 static errno_t
 475 utun_ctl_setopt(
 476         __unused kern_ctl_ref   kctlref,
 477         __unused u_int32_t              unit,
 478         void                                    *unitinfo,
 479         int                                             opt,
 480         void                                    *data,
 481         size_t                                  len)
 482 {
 483         struct utun_pcb                 *pcb = unitinfo;
 484         errno_t                                 result = 0;
 485
 486         /* check for privileges for privileged options */
 487         switch (opt) {
 488                 case UTUN_OPT_FLAGS:
 489                 case UTUN_OPT_EXT_IFDATA_STATS:
 490                 case UTUN_OPT_SET_DELEGATE_INTERFACE:
 491                         if (kauth_cred_issuser(kauth_cred_get()) == 0) {
 492                                 return EPERM;
 493                         }
 494                         break;
 495         }
 496
 497         switch (opt) {
 498                 case UTUN_OPT_FLAGS:
 499                         if (len != sizeof(u_int32_t))
 500                                 result = EMSGSIZE;
 501                         else
 502                                 pcb->utun_flags = *(u_int32_t *)data;
 503                         break;
 504
 505                 case UTUN_OPT_ENABLE_CRYPTO:
 506                         result = utun_ctl_enable_crypto(kctlref, unit, unitinfo, opt, data, len);
 507                         break;
 508
 509                 case UTUN_OPT_CONFIG_CRYPTO_KEYS:
 510                         result = utun_ctl_config_crypto_keys(kctlref, unit, unitinfo, opt, data, len);
 511                         break;
 512
 513                 case UTUN_OPT_UNCONFIG_CRYPTO_KEYS:
 514                         result = utun_ctl_unconfig_crypto_keys(kctlref, unit, unitinfo, opt, data, len);
 515                         break;
 516
 517                 case UTUN_OPT_DISABLE_CRYPTO:
 518                         result = utun_ctl_disable_crypto(kctlref, unit, unitinfo, opt, data, len);
 519                         break;
 520
 521                 case UTUN_OPT_STOP_CRYPTO_DATA_TRAFFIC:
 522                         result = utun_ctl_stop_crypto_data_traffic(kctlref, unit, unitinfo, opt, data, len);
 523                         break;
 524
 525                 case UTUN_OPT_START_CRYPTO_DATA_TRAFFIC:
 526                         result = utun_ctl_start_crypto_data_traffic(kctlref, unit, unitinfo, opt, data, len);
 527                         break;
 528
 529                 case UTUN_OPT_CONFIG_CRYPTO_FRAMER:
 530                         result = utun_ctl_config_crypto_framer(kctlref, unit, unitinfo, opt, data, len);
 531                         break;
 532
 533                 case UTUN_OPT_UNCONFIG_CRYPTO_FRAMER:
 534                         result = utun_ctl_unconfig_crypto_framer(kctlref, unit, unitinfo, opt, data, len);
 535                         break;
 536
 537                 case UTUN_OPT_EXT_IFDATA_STATS:
 538                         if (len != sizeof(int)) {
 539                                 result = EMSGSIZE;
 540                                 break;
 541                         }
 542                         pcb->utun_ext_ifdata_stats = (*(int *)data) ? 1 : 0;
 543                         break;
 544
 545                 case UTUN_OPT_INC_IFDATA_STATS_IN:
 546                 case UTUN_OPT_INC_IFDATA_STATS_OUT: {
 547                         struct utun_stats_param *utsp = (struct utun_stats_param *)data;
 548
 549                         if (utsp == NULL || len < sizeof(struct utun_stats_param)) {
 550                                 result = EINVAL;
 551                                 break;
 552                         }
 553                         if (!pcb->utun_ext_ifdata_stats) {
 554                                 result = EINVAL;
 555                                 break;
 556                         }
 557                         if (opt == UTUN_OPT_INC_IFDATA_STATS_IN)
 558                                 ifnet_stat_increment_in(pcb->utun_ifp, utsp->utsp_packets,
 559                                         utsp->utsp_bytes, utsp->utsp_errors);
 560                         else
 561                                 ifnet_stat_increment_out(pcb->utun_ifp, utsp->utsp_packets,
 562                                         utsp->utsp_bytes, utsp->utsp_errors);
 563                         break;
 564                 }
 565                 case UTUN_OPT_SET_DELEGATE_INTERFACE: {
 566                         ifnet_t         del_ifp = NULL;
 567                         char            name[IFNAMSIZ];
 568
 569                         if (len > IFNAMSIZ - 1) {
 570                                 result = EMSGSIZE;
 571                                 break;
 572                         }
 573                         if (len != 0) {    /* if len==0, del_ifp will be NULL causing the delegate to be removed */
 574                                 bcopy(data, name, len);
 575                                 name[len] = 0;
 576                                 result = ifnet_find_by_name(name, &del_ifp);
 577                         }
 578                         if (result == 0) {
 579                                 result = ifnet_set_delegate(pcb->utun_ifp, del_ifp);
 580                                 if (del_ifp)
 581                                         ifnet_release(del_ifp);
 582                         }
 583                         break;
 584                 }
 585                 case UTUN_OPT_MAX_PENDING_PACKETS: {
 586                         u_int32_t max_pending_packets = 0;
 587                         if (len != sizeof(u_int32_t)) {
 588                                 result = EMSGSIZE;
 589                                 break;
 590                         }
 591                         max_pending_packets = *(u_int32_t *)data;
 592                         if (max_pending_packets == 0) {
 593                                 result = EINVAL;
 594                                 break;
 595                         }
 596                         pcb->utun_max_pending_packets = max_pending_packets;
 597                         break;
 598                 }
 599                 default: {
 600                         result = ENOPROTOOPT;
 601                         break;
 602                 }
 603         }
 604
 605         return result;
 606 }
 607
 608 static errno_t
 609 utun_ctl_getopt(
 610         __unused kern_ctl_ref   kctlref,
 611         __unused u_int32_t              unit,
 612         void                                    *unitinfo,
 613         int                                             opt,
 614         void                                    *data,
 615         size_t                                  *len)
 616 {
 617         struct utun_pcb                 *pcb = unitinfo;
 618         errno_t                                 result = 0;
 619
 620         switch (opt) {
 621                 case UTUN_OPT_FLAGS:
 622                         if (*len != sizeof(u_int32_t))
 623                                 result = EMSGSIZE;
 624                         else
 625                                 *(u_int32_t *)data = pcb->utun_flags;
 626                         break;
 627
 628                 case UTUN_OPT_EXT_IFDATA_STATS:
 629                         if (*len != sizeof(int))
 630                                 result = EMSGSIZE;
 631                         else
 632                                 *(int *)data = (pcb->utun_ext_ifdata_stats) ? 1 : 0;
 633                         break;
 634
 635                 case UTUN_OPT_IFNAME:
 636                         *len = snprintf(data, *len, "%s%d", ifnet_name(pcb->utun_ifp), ifnet_unit(pcb->utun_ifp)) + 1;
 637                         break;
 638
 639                 case UTUN_OPT_GENERATE_CRYPTO_KEYS_IDX:
 640                         result = utun_ctl_generate_crypto_keys_idx(kctlref, unit, unitinfo, opt, data, len);
 641                         break;
 642                 case UTUN_OPT_MAX_PENDING_PACKETS: {
 643                         *len = sizeof(u_int32_t);
 644                         *((u_int32_t *)data) = pcb->utun_max_pending_packets;
 645                         break;
 646                 }
 647                 default:
 648                         result = ENOPROTOOPT;
 649                         break;
 650         }
 651
 652         return result;
 653 }
 654
 655 static void
 656 utun_ctl_rcvd(kern_ctl_ref kctlref, u_int32_t unit, void *unitinfo, int flags)
 657 {
 658 #pragma unused(kctlref, unit, flags)
 659         bool reenable_output = false;
 660         struct utun_pcb *pcb = unitinfo;
 661         if (pcb == NULL) {
 662                 return;
 663         }
 664         ifnet_lock_exclusive(pcb->utun_ifp);
 665         if (pcb->utun_pending_packets > 0) {
 666                 pcb->utun_pending_packets--;
 667                 if (pcb->utun_pending_packets < pcb->utun_max_pending_packets) {
 668                         reenable_output = true;
 669                 }
 670         }
 671
 672         if (reenable_output) {
 673                 errno_t error = ifnet_enable_output(pcb->utun_ifp);
 674                 if (error != 0) {
 675                         printf("utun_ctl_rcvd: ifnet_enable_output returned error %d\n", error);
 676                 }
 677         }
 678         ifnet_lock_done(pcb->utun_ifp);
 679 }
 680
 681 /* Network Interface functions */
 682 static void
 683 utun_start(ifnet_t interface)
 684 {
 685         mbuf_t data;
 686         struct utun_pcb*pcb = ifnet_softc(interface);
 687         for (;;) {
 688                 bool can_accept_packets = true;
 689                 ifnet_lock_shared(pcb->utun_ifp);
 690                 can_accept_packets = (pcb->utun_pending_packets < pcb->utun_max_pending_packets);
 691                 if (!can_accept_packets && pcb->utun_ctlref) {
 692                         u_int32_t difference = 0;
 693                         if (ctl_getenqueuereadable(pcb->utun_ctlref, pcb->utun_unit, &difference) == 0) {
 694                                 if (difference > 0) {
 695                                         // If the low-water mark has not yet been reached, we still need to enqueue data
 696                                         // into the buffer
 697                                         can_accept_packets = true;
 698                                 }
 699                         }
 700                 }
 701                 if (!can_accept_packets) {
 702                         errno_t error = ifnet_disable_output(interface);
 703                         if (error != 0) {
 704                                 printf("utun_start: ifnet_disable_output returned error %d\n", error);
 705                         }
 706                         ifnet_lock_done(pcb->utun_ifp);
 707                         break;
 708                 }
 709                 ifnet_lock_done(pcb->utun_ifp);
 710                 if (ifnet_dequeue(interface, &data) != 0)
 711                         break;
 712                 if (utun_output(interface, data) != 0)
 713                         break;
 714         }
 715 }
 716
 717 static errno_t
 718 utun_output(
 719                            ifnet_t      interface,
 720                            mbuf_t       data)
 721 {
 722         struct utun_pcb *pcb = ifnet_softc(interface);
 723         errno_t                 result;
 724
 725         if (m_pktlen(data) >= 4) {
 726                 bpf_tap_out(pcb->utun_ifp, DLT_NULL, data, 0, 0);
 727         }
 728
 729         if (pcb->utun_flags & UTUN_FLAGS_NO_OUTPUT) {
 730                 /* flush data */
 731                 mbuf_freem(data);
 732                 return 0;
 733         }
 734
 735         // otherwise, fall thru to ctl_enqueumbuf
 736         if (pcb->utun_ctlref) {
 737                 int     length;
 738
 739                 // only pass packets to utun-crypto if crypto is enabled and 'suspend data traffic' is not.
 740                 if ((pcb->utun_flags & (UTUN_FLAGS_CRYPTO | UTUN_FLAGS_CRYPTO_STOP_DATA_TRAFFIC)) == UTUN_FLAGS_CRYPTO) {
 741                         if (utun_pkt_crypto_output(pcb, &data) == 0) {
 742                                 return 0;
 743                         }
 744                 }
 745
 746                 /*
 747                  * The ABI requires the protocol in network byte order
 748                  */
 749                 if (m_pktlen(data) >= 4)
 750                         *(u_int32_t *)mbuf_data(data) = htonl(*(u_int32_t *)mbuf_data(data));
 751
 752                 length = mbuf_pkthdr_len(data);
 753                 // Increment packet count optimistically
 754                 ifnet_lock_exclusive(pcb->utun_ifp);
 755                 pcb->utun_pending_packets++;
 756                 ifnet_lock_done(pcb->utun_ifp);
 757                 result = ctl_enqueuembuf(pcb->utun_ctlref, pcb->utun_unit, data, CTL_DATA_EOR);
 758                 if (result != 0) {
 759                         // Decrement packet count if errored
 760                         ifnet_lock_exclusive(pcb->utun_ifp);
 761                         pcb->utun_pending_packets--;
 762                         ifnet_lock_done(pcb->utun_ifp);
 763                         mbuf_freem(data);
 764                         printf("utun_output - ctl_enqueuembuf failed: %d\n", result);
 765
 766                         ifnet_stat_increment_out(interface, 0, 0, 1);
 767                 }
 768                 else {
 769                         if (!pcb->utun_ext_ifdata_stats)
 770                                 ifnet_stat_increment_out(interface, 1, length, 0);
 771                 }
 772         }
 773         else
 774                 mbuf_freem(data);
 775
 776         return 0;
 777 }
 778
 779 static errno_t
 780 utun_demux(
 781         __unused ifnet_t        interface,
 782         mbuf_t                          data,
 783         __unused char           *frame_header,
 784         protocol_family_t       *protocol)
 785 {
 786
 787         while (data != NULL && mbuf_len(data) < 1) {
 788                 data = mbuf_next(data);
 789         }
 790
 791         if (data == NULL)
 792                 return ENOENT;
 793
 794         *protocol = *(u_int32_t *)mbuf_data(data);
 795         return 0;
 796 }
 797
 798 static errno_t
 799 utun_framer(
 800                    __unused ifnet_t                             interface,
 801                    mbuf_t                               *packet,
 802                         __unused const struct sockaddr *dest,
 803                         __unused const char *desk_linkaddr,
 804                         const char *frame_type,
 805                         u_int32_t *prepend_len,
 806                         u_int32_t *postpend_len)
 807 {
 808     if (mbuf_prepend(packet, sizeof(protocol_family_t), MBUF_DONTWAIT) != 0) {
 809                 printf("utun_framer - ifnet_output prepend failed\n");
 810
 811                 ifnet_stat_increment_out(interface, 0, 0, 1);
 812
 813                 // just return, because the buffer was freed in mbuf_prepend
 814         return EJUSTRETURN;
 815     }
 816         if (prepend_len != NULL)
 817                 *prepend_len = sizeof(protocol_family_t);
 818         if (postpend_len != NULL)
 819                 *postpend_len = 0;
 820
 821     // place protocol number at the beginning of the mbuf
 822     *(protocol_family_t *)mbuf_data(*packet) = *(protocol_family_t *)(uintptr_t)(size_t)frame_type;
 823
 824     return 0;
 825 }
 826
 827 static errno_t
 828 utun_add_proto(
 829         __unused ifnet_t                                                interface,
 830         protocol_family_t                                               protocol,
 831         __unused const struct ifnet_demux_desc  *demux_array,
 832         __unused u_int32_t                                              demux_count)
 833 {
 834         switch(protocol) {
 835                 case PF_INET:
 836                         return 0;
 837                 case PF_INET6:
 838                         return 0;
 839                 default:
 840                         break;
 841         }
 842
 843         return ENOPROTOOPT;
 844 }
 845
 846 static errno_t
 847 utun_del_proto(
 848         __unused ifnet_t                        interface,
 849         __unused protocol_family_t      protocol)
 850 {
 851         return 0;
 852 }
 853
 854 static errno_t
 855 utun_ioctl(
 856         ifnet_t         interface,
 857         u_long          command,
 858         void            *data)
 859 {
 860         errno_t result = 0;
 861
 862         switch(command) {
 863                 case SIOCSIFMTU:
 864                         ifnet_set_mtu(interface, ((struct ifreq*)data)->ifr_mtu);
 865                         break;
 866
 867                 case SIOCSIFFLAGS:
 868                         /* ifioctl() takes care of it */
 869                         break;
 870
 871                 default:
 872                         result = EOPNOTSUPP;
 873         }
 874
 875         return result;
 876 }
 877
 878 static void
 879 utun_detached(
 880         ifnet_t interface)
 881 {
 882         struct utun_pcb *pcb = ifnet_softc(interface);
 883
 884         utun_free(pcb);
 885
 886         OSDecrementAtomic(&utun_ifcount);
 887 }
 888
 889 /* Protocol Handlers */
 890
 891 static errno_t
 892 utun_proto_input(
 893         __unused ifnet_t        interface,
 894         protocol_family_t       protocol,
 895         mbuf_t                          m,
 896         __unused char           *frame_header)
 897 {
 898
 899         // remove protocol family first
 900         mbuf_adj(m, sizeof(u_int32_t));
 901
 902         if (proto_input(protocol, m) != 0)
 903                 m_freem(m);
 904
 905         return 0;
 906 }
 907
 908 static errno_t
 909 utun_proto_pre_output(
 910         __unused ifnet_t        interface,
 911         protocol_family_t       protocol,
 912         __unused mbuf_t         *packet,
 913         __unused const struct sockaddr *dest,
 914         __unused void *route,
 915         __unused char *frame_type,
 916         __unused char *link_layer_dest)
 917 {
 918
 919         *(protocol_family_t *)(void *)frame_type = protocol;
 920                 return 0;
 921 }
 922
 923 static errno_t
 924 utun_attach_proto(
 925         ifnet_t                         interface,
 926         protocol_family_t       protocol)
 927 {
 928         struct ifnet_attach_proto_param proto;
 929         errno_t                                                 result;
 930
 931         bzero(&proto, sizeof(proto));
 932         proto.input = utun_proto_input;
 933         proto.pre_output = utun_proto_pre_output;
 934
 935         result = ifnet_attach_protocol(interface, protocol, &proto);
 936         if (result != 0 && result != EEXIST) {
 937                 printf("utun_attach_inet - ifnet_attach_protocol %d failed: %d\n",
 938                         protocol, result);
 939         }
 940
 941         return result;
 942 }
 943
 944 errno_t
 945 utun_pkt_input (struct utun_pcb *pcb, mbuf_t m)
 946 {
 947         errno_t result;
 948         protocol_family_t protocol = 0;
 949
 950         mbuf_pkthdr_setrcvif(m, pcb->utun_ifp);
 951
 952         if (m_pktlen(m) >= 4)  {
 953                 protocol = *(u_int32_t *)mbuf_data(m);
 954
 955                 bpf_tap_in(pcb->utun_ifp, DLT_NULL, m, 0, 0);
 956         }
 957         if (pcb->utun_flags & UTUN_FLAGS_NO_INPUT) {
 958                 /* flush data */
 959                 mbuf_freem(m);
 960                 return 0;
 961         }
 962
 963         // quick exit for keepalive packets
 964         if (protocol == AF_UTUN && pcb->utun_flags & UTUN_FLAGS_CRYPTO) {
 965                 if (utun_pkt_crypto_output(pcb, &m) == 0) {
 966                         return 0;
 967                 }
 968                 printf("%s: utun_pkt_crypto_output failed, flags %x\n", __FUNCTION__, pcb->utun_flags);
 969                 return EINVAL;
 970         }
 971
 972         if (!pcb->utun_ext_ifdata_stats) {
 973                 struct ifnet_stat_increment_param       incs;
 974
 975                 bzero(&incs, sizeof(incs));
 976                 incs.packets_in = 1;
 977                 incs.bytes_in = mbuf_pkthdr_len(m);
 978                 result = ifnet_input(pcb->utun_ifp, m, &incs);
 979         } else {
 980                 result = ifnet_input(pcb->utun_ifp, m, NULL);
 981         }
 982         if (result != 0) {
 983                 ifnet_stat_increment_in(pcb->utun_ifp, 0, 0, 1);
 984
 985                 printf("%s - ifnet_input failed: %d\n", __FUNCTION__, result);
 986                 mbuf_freem(m);
 987         }
 988
 989         return 0;
 990 }