bsd/netinet/kpi_ipfilter.c

   1 /*
   2  * Copyright (c) 2003 Apple Computer, 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 #include <sys/param.h>  /* for definition of NULL */
  30 #include <sys/errno.h>
  31 #include <sys/malloc.h>
  32 #include <sys/socket.h>
  33 #include <sys/mbuf.h>
  34 #include <sys/systm.h>
  35
  36 #define _IP_VHL
  37 #include <net/if_var.h>
  38 #include <net/route.h>
  39 #include <net/kpi_protocol.h>
  40
  41 #include <netinet/in_systm.h>
  42 #include <netinet/in.h>
  43 #include <netinet/in_var.h>
  44 #include <netinet6/in6_var.h>
  45 #include <netinet/ip.h>
  46 #include <netinet/ip6.h>
  47 #include <netinet/ip_var.h>
  48 #include <netinet6/ip6_var.h>
  49 #include <netinet/kpi_ipfilter_var.h>
  50
  51 /*
  52  * kipf_lock and kipf_ref protect the linkage of the list of IP filters
  53  * An IP filter can be removed only when kipf_ref is zero
  54  * If an IP filter cannot be removed because kipf_ref is not null, then
  55  * the IP filter is marjed and kipf_delayed_remove is set so that when
  56  * kipf_ref eventually goes down to zero, the IP filter is removed
  57  */
  58 static lck_mtx_t *kipf_lock = 0;
  59 static unsigned long kipf_ref = 0;
  60 static unsigned long kipf_delayed_remove = 0;
  61
  62 __private_extern__ struct ipfilter_list ipv4_filters = TAILQ_HEAD_INITIALIZER(ipv4_filters);
  63 __private_extern__ struct ipfilter_list ipv6_filters = TAILQ_HEAD_INITIALIZER(ipv6_filters);
  64 __private_extern__ struct ipfilter_list tbr_filters = TAILQ_HEAD_INITIALIZER(tbr_filters);
  65
  66 __private_extern__ void
  67 ipf_ref(void)
  68 {
  69         lck_mtx_lock(kipf_lock);
  70     kipf_ref++;
  71         lck_mtx_unlock(kipf_lock);
  72 }
  73
  74 __private_extern__ void
  75 ipf_unref(void)
  76 {
  77         lck_mtx_lock(kipf_lock);
  78
  79     if (kipf_ref == 0)
  80         panic("ipf_unref: kipf_ref == 0\n");
  81
  82     kipf_ref--;
  83     if (kipf_ref == 0 && kipf_delayed_remove != 0) {
  84         struct ipfilter *filter;
  85
  86                 while ((filter = TAILQ_FIRST(&tbr_filters))) {
  87                         ipf_detach_func ipf_detach = filter->ipf_filter.ipf_detach;
  88                         void* cookie = filter->ipf_filter.cookie;
  89
  90                         TAILQ_REMOVE(filter->ipf_head, filter, ipf_link);
  91                         TAILQ_REMOVE(&tbr_filters, filter, ipf_tbr);
  92                         kipf_delayed_remove--;
  93
  94                         if (ipf_detach) {
  95                                 lck_mtx_unlock(kipf_lock);
  96                                 ipf_detach(cookie);
  97                                 lck_mtx_lock(kipf_lock);
  98                                 /* In case some filter got to run while we released the lock */
  99                                 if (kipf_ref != 0)
 100                                         break;
 101                         }
 102                 }
 103         }
 104         lck_mtx_unlock(kipf_lock);
 105 }
 106
 107 static errno_t
 108 ipf_add(
 109         const struct ipf_filter* filter,
 110         ipfilter_t *filter_ref,
 111         struct ipfilter_list *head)
 112 {
 113         struct ipfilter *new_filter;
 114         if (filter->name == NULL || (filter->ipf_input == NULL && filter->ipf_output == NULL))
 115                 return EINVAL;
 116
 117         MALLOC(new_filter, struct ipfilter*, sizeof(*new_filter), M_IFADDR, M_WAITOK);
 118         if (new_filter == NULL)
 119                 return ENOMEM;
 120
 121         lck_mtx_lock(kipf_lock);
 122         new_filter->ipf_filter = *filter;
 123         new_filter->ipf_head = head;
 124
 125         /*
 126          * 3957298
 127          * Make sure third parties have a chance to filter packets before
 128          * SharedIP. Always SharedIP at the end of the list.
 129          */
 130         if (filter->name != NULL &&
 131                 strcmp(filter->name, "com.apple.nke.SharedIP") == 0) {
 132                 TAILQ_INSERT_TAIL(head, new_filter, ipf_link);
 133         }
 134         else {
 135                 TAILQ_INSERT_HEAD(head, new_filter, ipf_link);
 136         }
 137
 138         lck_mtx_unlock(kipf_lock);
 139
 140         *filter_ref = (ipfilter_t)new_filter;
 141         return 0;
 142 }
 143
 144 errno_t
 145 ipf_addv4(
 146         const struct ipf_filter* filter,
 147         ipfilter_t *filter_ref)
 148 {
 149         return ipf_add(filter, filter_ref, &ipv4_filters);
 150 }
 151
 152 errno_t
 153 ipf_addv6(
 154         const struct ipf_filter* filter,
 155         ipfilter_t *filter_ref)
 156 {
 157         return ipf_add(filter, filter_ref, &ipv6_filters);
 158 }
 159
 160 errno_t
 161 ipf_remove(
 162         ipfilter_t filter_ref)
 163 {
 164         struct ipfilter *match = (struct ipfilter*)filter_ref;
 165         struct ipfilter_list *head;
 166
 167         if (match == 0 || (match->ipf_head != &ipv4_filters && match->ipf_head != &ipv6_filters))
 168                 return EINVAL;
 169
 170         head = match->ipf_head;
 171
 172         lck_mtx_lock(kipf_lock);
 173         TAILQ_FOREACH(match, head, ipf_link) {
 174                 if (match == (struct ipfilter*)filter_ref) {
 175                         ipf_detach_func ipf_detach = match->ipf_filter.ipf_detach;
 176                         void* cookie = match->ipf_filter.cookie;
 177
 178                         /*
 179                          * Cannot detach when they are filters running
 180                          */
 181                         if (kipf_ref) {
 182                                 kipf_delayed_remove++;
 183                                 TAILQ_INSERT_TAIL(&tbr_filters, match, ipf_tbr);
 184                                 match->ipf_filter.ipf_input = 0;
 185                                 match->ipf_filter.ipf_output = 0;
 186                                 lck_mtx_unlock(kipf_lock);
 187                         } else {
 188                                 TAILQ_REMOVE(head, match, ipf_link);
 189                                 lck_mtx_unlock(kipf_lock);
 190                                 if (ipf_detach)
 191                                         ipf_detach(cookie);
 192                                 FREE(match, M_IFADDR);
 193                         }
 194                         return 0;
 195                 }
 196         }
 197         lck_mtx_unlock(kipf_lock);
 198
 199         return ENOENT;
 200 }
 201
 202 int log_for_en1 = 0;
 203
 204 errno_t
 205 ipf_inject_input(
 206         mbuf_t data,
 207         ipfilter_t filter_ref)
 208 {
 209         struct mbuf     *m = (struct mbuf*)data;
 210         struct m_tag *mtag = 0;
 211         struct ip *ip = mtod(m, struct ip *);
 212         u_int8_t        vers;
 213         int hlen;
 214         errno_t error = 0;
 215         protocol_family_t proto;
 216
 217         vers = IP_VHL_V(ip->ip_vhl);
 218
 219         switch (vers) {
 220                 case 4:
 221                         proto = PF_INET;
 222                         break;
 223                 case 6:
 224                         proto = PF_INET6;
 225                         break;
 226                 default:
 227                         error = ENOTSUP;
 228                         goto done;
 229         }
 230
 231         if (filter_ref == 0 && m->m_pkthdr.rcvif == 0) {
 232                 m->m_pkthdr.rcvif = ifunit("lo0");
 233                 m->m_pkthdr.csum_data = 0;
 234                 m->m_pkthdr.csum_flags = 0;
 235                 if (vers == 4) {
 236                         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 237                         ip->ip_sum = 0;
 238                         ip->ip_sum = in_cksum(m, hlen);
 239                 }
 240         }
 241         if (filter_ref != 0) {
 242                 mtag = m_tag_alloc(KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_IPFILT,
 243                                                    sizeof (ipfilter_t), M_NOWAIT);
 244                 if (mtag == NULL) {
 245                         error = ENOMEM;
 246                         goto done;
 247                 }
 248                 *(ipfilter_t*)(mtag+1) = filter_ref;
 249                 m_tag_prepend(m, mtag);
 250         }
 251
 252         error = proto_inject(proto, data);
 253
 254 done:
 255         return error;
 256 }
 257
 258 static errno_t
 259 ipf_injectv4_out(
 260         mbuf_t data,
 261         ipfilter_t filter_ref,
 262         ipf_pktopts_t options)
 263 {
 264         struct route ro;
 265         struct sockaddr_in      *sin = (struct sockaddr_in*)&ro.ro_dst;
 266         struct ip       *ip;
 267         struct mbuf     *m = (struct mbuf*)data;
 268         errno_t error = 0;
 269         struct m_tag *mtag = 0;
 270         struct ip_moptions *imo = 0, ip_moptions;
 271
 272         /* Make the IP header contiguous in the mbuf */
 273         if ((size_t)m->m_len < sizeof(struct ip)) {
 274                 m = m_pullup(m, sizeof(struct ip));
 275                 if (m == NULL) return ENOMEM;
 276         }
 277         ip = (struct ip*)m_mtod(m);
 278
 279         if (filter_ref != 0) {
 280                 mtag = m_tag_alloc(KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_IPFILT,
 281                                                    sizeof (ipfilter_t), M_NOWAIT);
 282                 if (mtag == NULL) {
 283                         m_freem(m);
 284                         return ENOMEM;
 285                 }
 286                 *(ipfilter_t*)(mtag+1) = filter_ref;
 287                 m_tag_prepend(m, mtag);
 288         }
 289
 290         if (options && (options->ippo_flags & IPPOF_MCAST_OPTS)) {
 291                 imo = &ip_moptions;
 292
 293                 bzero(imo, sizeof(struct ip6_moptions));
 294                 imo->imo_multicast_ifp = options->ippo_mcast_ifnet;
 295                 imo->imo_multicast_ttl = options->ippo_mcast_ttl;
 296                 imo->imo_multicast_loop = options->ippo_mcast_loop;
 297         }
 298
 299         /* Fill out a route structure and get a route */
 300         bzero(&ro, sizeof(struct route));
 301         sin->sin_len = sizeof(struct sockaddr_in);
 302         sin->sin_family = AF_INET;
 303         sin->sin_port = 0;
 304         sin->sin_addr = ip->ip_dst;
 305         rtalloc(&ro);
 306         if (ro.ro_rt == NULL) {
 307                 m_freem(m);
 308                 return ENETUNREACH;
 309         }
 310
 311         /* Put ip_len and ip_off in host byte order, ip_output expects that */
 312         NTOHS(ip->ip_len);
 313         NTOHS(ip->ip_off);
 314
 315         /* Send  */
 316         error = ip_output(m, NULL, &ro, IP_ALLOWBROADCAST | IP_RAWOUTPUT, imo, NULL);
 317
 318         /* Release the route */
 319         if (ro.ro_rt)
 320                 rtfree(ro.ro_rt);
 321
 322         return error;
 323 }
 324
 325 #if INET6
 326 static errno_t
 327 ipf_injectv6_out(
 328         mbuf_t data,
 329         ipfilter_t filter_ref,
 330         ipf_pktopts_t options)
 331 {
 332         struct route_in6 ro;
 333         struct sockaddr_in6     *sin6 = &ro.ro_dst;
 334         struct ip6_hdr  *ip6;
 335         struct mbuf     *m = (struct mbuf*)data;
 336         errno_t error = 0;
 337         struct m_tag *mtag = 0;
 338         struct ip6_moptions *im6o = 0, ip6_moptions;
 339
 340         /* Make the IP header contiguous in the mbuf */
 341         if ((size_t)m->m_len < sizeof(struct ip6_hdr)) {
 342                 m = m_pullup(m, sizeof(struct ip6_hdr));
 343                 if (m == NULL) return ENOMEM;
 344         }
 345         ip6 = (struct ip6_hdr*)m_mtod(m);
 346
 347         if (filter_ref != 0) {
 348                 mtag = m_tag_alloc(KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_IPFILT,
 349                                                    sizeof (ipfilter_t), M_NOWAIT);
 350                 if (mtag == NULL) {
 351                         m_freem(m);
 352                         return ENOMEM;
 353                 }
 354                 *(ipfilter_t*)(mtag+1) = filter_ref;
 355                 m_tag_prepend(m, mtag);
 356         }
 357
 358         if (options && (options->ippo_flags & IPPOF_MCAST_OPTS)) {
 359                 im6o = &ip6_moptions;
 360
 361                 bzero(im6o, sizeof(struct ip6_moptions));
 362                 im6o->im6o_multicast_ifp = options->ippo_mcast_ifnet;
 363                 im6o->im6o_multicast_hlim = options->ippo_mcast_ttl;
 364                 im6o->im6o_multicast_loop = options->ippo_mcast_loop;
 365         }
 366
 367
 368         /* Fill out a route structure and get a route */
 369         bzero(&ro, sizeof(struct route_in6));
 370         sin6->sin6_len = sizeof(struct sockaddr_in6);
 371         sin6->sin6_family = AF_INET6;
 372         sin6->sin6_addr = ip6->ip6_dst;
 373 #if 0
 374         /* This is breaks loopback multicast! */
 375         /* The scope ID should already at s6_addr16[1] */
 376         if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
 377                 /* Hack, pull the scope_id out of the dest addr */
 378                 sin6->sin6_scope_id = ntohs(ip6->ip6_dst.s6_addr16[1]);
 379                 ip6->ip6_dst.s6_addr16[1] = 0;
 380         } else
 381                 sin6->sin6_scope_id = 0;
 382 #endif
 383         rtalloc((struct route*)&ro);
 384         if (ro.ro_rt == NULL) {
 385                 m_freem(m);
 386                 return ENETUNREACH;
 387         }
 388
 389         /* Send  */
 390         error = ip6_output(m, NULL, &ro, 0, im6o, NULL, 0);
 391
 392         /* Release the route */
 393         if (ro.ro_rt)
 394                 rtfree(ro.ro_rt);
 395
 396         return error;
 397 }
 398 #endif /* INET6 */
 399
 400 errno_t
 401 ipf_inject_output(
 402         mbuf_t data,
 403         ipfilter_t filter_ref,
 404         ipf_pktopts_t options)
 405 {
 406         struct mbuf     *m = (struct mbuf*)data;
 407         u_int8_t        vers;
 408         errno_t         error = 0;
 409
 410         /* Make one byte of the header contiguous in the mbuf */
 411         if (m->m_len < 1) {
 412                 m = m_pullup(m, 1);
 413                 if (m == NULL)
 414                         goto done;
 415         }
 416
 417         vers = (*(u_int8_t*)m_mtod(m)) >> 4;
 418         switch (vers)
 419         {
 420                 case 4:
 421                         error = ipf_injectv4_out(data, filter_ref, options);
 422                         break;
 423 #if INET6
 424                 case 6:
 425                         error = ipf_injectv6_out(data, filter_ref, options);
 426                         break;
 427 #endif
 428                 default:
 429                         m_freem(m);
 430                         error = ENOTSUP;
 431                         break;
 432         }
 433
 434 done:
 435         return error;
 436 }
 437
 438 __private_extern__ ipfilter_t
 439 ipf_get_inject_filter(struct mbuf *m)
 440 {
 441         ipfilter_t filter_ref = 0;
 442         struct m_tag *mtag;
 443
 444         mtag = m_tag_locate(m, KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_IPFILT, NULL);
 445         if (mtag) {
 446                 filter_ref = *(ipfilter_t *)(mtag+1);
 447
 448                 m_tag_delete(m, mtag);
 449         }
 450         return filter_ref;
 451 }
 452
 453 __private_extern__ int
 454 ipf_init(void)
 455 {
 456         int error = 0;
 457         lck_grp_attr_t *grp_attributes = 0;
 458         lck_attr_t *lck_attributes = 0;
 459         lck_grp_t *lck_grp = 0;
 460
 461         grp_attributes = lck_grp_attr_alloc_init();
 462         if (grp_attributes == 0) {
 463                 printf("ipf_init: lck_grp_attr_alloc_init failed\n");
 464                 error = ENOMEM;
 465                 goto done;
 466         }
 467
 468         lck_grp = lck_grp_alloc_init("IP Filter", grp_attributes);
 469         if (lck_grp == 0) {
 470                 printf("ipf_init: lck_grp_alloc_init failed\n");
 471                 error = ENOMEM;
 472                 goto done;
 473         }
 474
 475         lck_attributes = lck_attr_alloc_init();
 476         if (lck_attributes == 0) {
 477                 printf("ipf_init: lck_attr_alloc_init failed\n");
 478                 error = ENOMEM;
 479                 goto done;
 480         }
 481
 482         kipf_lock = lck_mtx_alloc_init(lck_grp, lck_attributes);
 483         if (kipf_lock == 0) {
 484                 printf("ipf_init: lck_mtx_alloc_init failed\n");
 485                 error = ENOMEM;
 486                 goto done;
 487         }
 488         done:
 489         if (error != 0) {
 490                 if (kipf_lock) {
 491                         lck_mtx_free(kipf_lock, lck_grp);
 492                         kipf_lock = 0;
 493                 }
 494         }
 495         if (lck_grp) {
 496                 lck_grp_free(lck_grp);
 497                 lck_grp = 0;
 498         }
 499         if (grp_attributes) {
 500                 lck_grp_attr_free(grp_attributes);
 501                 grp_attributes = 0;
 502         }
 503         if (lck_attributes) {
 504                 lck_attr_free(lck_attributes);
 505                 lck_attributes = 0;
 506         }
 507
 508         return error;
 509 }