bsd/netinet/kpi_ipfilter.c

   1 /*
   2  * Copyright (c) 2004-2012 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 #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 #include <libkern/OSAtomic.h>
  36
  37 #include <machine/endian.h>
  38
  39 #define _IP_VHL
  40 #include <net/if_var.h>
  41 #include <net/route.h>
  42 #include <net/kpi_protocol.h>
  43
  44 #include <netinet/in_systm.h>
  45 #include <netinet/in.h>
  46 #include <netinet/in_var.h>
  47 #include <netinet6/in6_var.h>
  48 #include <netinet/ip.h>
  49 #include <netinet/ip6.h>
  50 #include <netinet/ip_var.h>
  51 #include <netinet6/ip6_var.h>
  52 #include <netinet/kpi_ipfilter_var.h>
  53
  54
  55 /*
  56  * kipf_lock and kipf_ref protect the linkage of the list of IP filters
  57  * An IP filter can be removed only when kipf_ref is zero
  58  * If an IP filter cannot be removed because kipf_ref is not null, then
  59  * the IP filter is marjed and kipf_delayed_remove is set so that when
  60  * kipf_ref eventually goes down to zero, the IP filter is removed
  61  */
  62 decl_lck_mtx_data(static, kipf_lock_data);
  63 static lck_mtx_t *kipf_lock = &kipf_lock_data;
  64 static u_int32_t kipf_ref = 0;
  65 static u_int32_t kipf_delayed_remove = 0;
  66 u_int32_t kipf_count = 0;
  67
  68 __private_extern__ struct ipfilter_list ipv4_filters = TAILQ_HEAD_INITIALIZER(ipv4_filters);
  69 __private_extern__ struct ipfilter_list ipv6_filters = TAILQ_HEAD_INITIALIZER(ipv6_filters);
  70 __private_extern__ struct ipfilter_list tbr_filters = TAILQ_HEAD_INITIALIZER(tbr_filters);
  71
  72 __private_extern__ void
  73 ipf_ref(void)
  74 {
  75         lck_mtx_lock(kipf_lock);
  76     kipf_ref++;
  77         lck_mtx_unlock(kipf_lock);
  78 }
  79
  80 __private_extern__ void
  81 ipf_unref(void)
  82 {
  83         lck_mtx_lock(kipf_lock);
  84
  85     if (kipf_ref == 0)
  86         panic("ipf_unref: kipf_ref == 0\n");
  87
  88     kipf_ref--;
  89     if (kipf_ref == 0 && kipf_delayed_remove != 0) {
  90         struct ipfilter *filter;
  91
  92                 while ((filter = TAILQ_FIRST(&tbr_filters))) {
  93                         ipf_detach_func ipf_detach = filter->ipf_filter.ipf_detach;
  94                         void* cookie = filter->ipf_filter.cookie;
  95
  96                         TAILQ_REMOVE(filter->ipf_head, filter, ipf_link);
  97                         TAILQ_REMOVE(&tbr_filters, filter, ipf_tbr);
  98                         kipf_delayed_remove--;
  99
 100                         if (ipf_detach) {
 101                                 lck_mtx_unlock(kipf_lock);
 102                                 ipf_detach(cookie);
 103                                 lck_mtx_lock(kipf_lock);
 104                                 /* In case some filter got to run while we released the lock */
 105                                 if (kipf_ref != 0)
 106                                         break;
 107                         }
 108                 }
 109         }
 110         lck_mtx_unlock(kipf_lock);
 111 }
 112
 113 static errno_t
 114 ipf_add(
 115         const struct ipf_filter* filter,
 116         ipfilter_t *filter_ref,
 117         struct ipfilter_list *head)
 118 {
 119         struct ipfilter *new_filter;
 120         if (filter->name == NULL || (filter->ipf_input == NULL && filter->ipf_output == NULL))
 121                 return EINVAL;
 122
 123         MALLOC(new_filter, struct ipfilter*, sizeof(*new_filter), M_IFADDR, M_WAITOK);
 124         if (new_filter == NULL)
 125                 return ENOMEM;
 126
 127         lck_mtx_lock(kipf_lock);
 128         new_filter->ipf_filter = *filter;
 129         new_filter->ipf_head = head;
 130
 131         TAILQ_INSERT_HEAD(head, new_filter, ipf_link);
 132
 133         lck_mtx_unlock(kipf_lock);
 134
 135         *filter_ref = (ipfilter_t)new_filter;
 136
 137         /* This will force TCP to re-evaluate its use of TSO */
 138         OSAddAtomic(1, &kipf_count);
 139         if (use_routegenid)
 140                 routegenid_update();
 141
 142         return 0;
 143 }
 144
 145 errno_t
 146 ipf_addv4(
 147         const struct ipf_filter* filter,
 148         ipfilter_t *filter_ref)
 149 {
 150         return ipf_add(filter, filter_ref, &ipv4_filters);
 151 }
 152
 153 errno_t
 154 ipf_addv6(
 155         const struct ipf_filter* filter,
 156         ipfilter_t *filter_ref)
 157 {
 158         return ipf_add(filter, filter_ref, &ipv6_filters);
 159 }
 160
 161 errno_t
 162 ipf_remove(
 163         ipfilter_t filter_ref)
 164 {
 165         struct ipfilter *match = (struct ipfilter*)filter_ref;
 166         struct ipfilter_list *head;
 167
 168         if (match == 0 || (match->ipf_head != &ipv4_filters && match->ipf_head != &ipv6_filters))
 169                 return EINVAL;
 170
 171         head = match->ipf_head;
 172
 173         lck_mtx_lock(kipf_lock);
 174         TAILQ_FOREACH(match, head, ipf_link) {
 175                 if (match == (struct ipfilter*)filter_ref) {
 176                         ipf_detach_func ipf_detach = match->ipf_filter.ipf_detach;
 177                         void* cookie = match->ipf_filter.cookie;
 178
 179                         /*
 180                          * Cannot detach when they are filters running
 181                          */
 182                         if (kipf_ref) {
 183                                 kipf_delayed_remove++;
 184                                 TAILQ_INSERT_TAIL(&tbr_filters, match, ipf_tbr);
 185                                 match->ipf_filter.ipf_input = 0;
 186                                 match->ipf_filter.ipf_output = 0;
 187                                 lck_mtx_unlock(kipf_lock);
 188                         } else {
 189                                 TAILQ_REMOVE(head, match, ipf_link);
 190                                 lck_mtx_unlock(kipf_lock);
 191                                 if (ipf_detach)
 192                                         ipf_detach(cookie);
 193                                 FREE(match, M_IFADDR);
 194
 195                                 /* This will force TCP to re-evaluate its use of TSO */
 196                                 OSAddAtomic(-1, &kipf_count);
 197                                 if (use_routegenid)
 198                                         routegenid_update();
 199
 200                         }
 201                         return 0;
 202                 }
 203         }
 204         lck_mtx_unlock(kipf_lock);
 205
 206         return ENOENT;
 207 }
 208
 209 int log_for_en1 = 0;
 210
 211 errno_t
 212 ipf_inject_input(
 213         mbuf_t data,
 214         ipfilter_t filter_ref)
 215 {
 216         struct mbuf     *m = (struct mbuf*)data;
 217         struct m_tag *mtag = 0;
 218         struct ip *ip = mtod(m, struct ip *);
 219         u_int8_t        vers;
 220         int hlen;
 221         errno_t error = 0;
 222         protocol_family_t proto;
 223
 224         vers = IP_VHL_V(ip->ip_vhl);
 225
 226         switch (vers) {
 227                 case 4:
 228                         proto = PF_INET;
 229                         break;
 230                 case 6:
 231                         proto = PF_INET6;
 232                         break;
 233                 default:
 234                         error = ENOTSUP;
 235                         goto done;
 236         }
 237
 238         if (filter_ref == 0 && m->m_pkthdr.rcvif == 0) {
 239                 m->m_pkthdr.rcvif = lo_ifp;
 240                 m->m_pkthdr.csum_data = 0;
 241                 m->m_pkthdr.csum_flags = 0;
 242                 if (vers == 4) {
 243                         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 244                         ip->ip_sum = 0;
 245                         ip->ip_sum = in_cksum(m, hlen);
 246                 }
 247         }
 248         if (filter_ref != 0) {
 249                 mtag = m_tag_create(KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_IPFILT,
 250                                                    sizeof (ipfilter_t), M_NOWAIT, m);
 251                 if (mtag == NULL) {
 252                         error = ENOMEM;
 253                         goto done;
 254                 }
 255                 *(ipfilter_t*)(mtag+1) = filter_ref;
 256                 m_tag_prepend(m, mtag);
 257         }
 258
 259         error = proto_inject(proto, data);
 260
 261 done:
 262         return error;
 263 }
 264
 265 static errno_t
 266 ipf_injectv4_out(mbuf_t data, ipfilter_t filter_ref, ipf_pktopts_t options)
 267 {
 268         struct route ro;
 269         struct ip       *ip;
 270         struct mbuf     *m = (struct mbuf*)data;
 271         errno_t error = 0;
 272         struct m_tag *mtag = NULL;
 273         struct ip_moptions *imo = NULL;
 274         struct ip_out_args ipoa = { IFSCOPE_NONE, { 0 }, 0 };
 275
 276         /* Make the IP header contiguous in the mbuf */
 277         if ((size_t)m->m_len < sizeof (struct ip)) {
 278                 m = m_pullup(m, sizeof (struct ip));
 279                 if (m == NULL)
 280                         return (ENOMEM);
 281         }
 282         ip = (struct ip *)m_mtod(m);
 283
 284         if (filter_ref != 0) {
 285                 mtag = m_tag_create(KERNEL_MODULE_TAG_ID,
 286                     KERNEL_TAG_TYPE_IPFILT, sizeof (ipfilter_t), M_NOWAIT, m);
 287                 if (mtag == NULL) {
 288                         m_freem(m);
 289                         return (ENOMEM);
 290                 }
 291                 *(ipfilter_t *)(mtag + 1) = filter_ref;
 292                 m_tag_prepend(m, mtag);
 293         }
 294
 295         if (options != NULL && (options->ippo_flags & IPPOF_MCAST_OPTS) &&
 296             (imo = ip_allocmoptions(M_DONTWAIT)) != NULL) {
 297                 imo->imo_multicast_ifp = options->ippo_mcast_ifnet;
 298                 imo->imo_multicast_ttl = options->ippo_mcast_ttl;
 299                 imo->imo_multicast_loop = options->ippo_mcast_loop;
 300         }
 301
 302         if (options != NULL) {
 303                 if (options->ippo_flags & IPPOF_SELECT_SRCIF)
 304                         ipoa.ipoa_flags |= IPOAF_SELECT_SRCIF;
 305                 if (options->ippo_flags & IPPOF_BOUND_IF) {
 306                         ipoa.ipoa_flags |= IPOAF_BOUND_IF;
 307                         ipoa.ipoa_boundif = options->ippo_flags >>
 308                             IPPOF_SHIFT_IFSCOPE;
 309                 }
 310                 if (options->ippo_flags & IPPOF_NO_IFT_CELLULAR)
 311                         ipoa.ipoa_flags |= IPOAF_NO_CELLULAR;
 312                 if (options->ippo_flags & IPPOF_BOUND_SRCADDR)
 313                         ipoa.ipoa_flags |= IPOAF_BOUND_SRCADDR;
 314         }
 315
 316         bzero(&ro, sizeof(struct route));
 317
 318         /* Put ip_len and ip_off in host byte order, ip_output expects that */
 319
 320 #if BYTE_ORDER != BIG_ENDIAN
 321         NTOHS(ip->ip_len);
 322         NTOHS(ip->ip_off);
 323 #endif
 324
 325         /* Send; enforce source interface selection via IP_OUTARGS flag */
 326         error = ip_output(m, NULL, &ro,
 327             IP_ALLOWBROADCAST | IP_RAWOUTPUT | IP_OUTARGS, imo, &ipoa);
 328
 329         /* Release the route */
 330         if (ro.ro_rt)
 331                 rtfree(ro.ro_rt);
 332
 333         if (imo != NULL)
 334                 IMO_REMREF(imo);
 335
 336         return (error);
 337 }
 338
 339 #if INET6
 340 static errno_t
 341 ipf_injectv6_out(mbuf_t data, ipfilter_t filter_ref, ipf_pktopts_t options)
 342 {
 343         struct route_in6 ro;
 344         struct ip6_hdr  *ip6;
 345         struct mbuf     *m = (struct mbuf*)data;
 346         errno_t error = 0;
 347         struct m_tag *mtag = NULL;
 348         struct ip6_moptions *im6o = NULL;
 349         struct ip6_out_args ip6oa = { IFSCOPE_NONE, { 0 }, 0 };
 350
 351         /* Make the IP header contiguous in the mbuf */
 352         if ((size_t)m->m_len < sizeof(struct ip6_hdr)) {
 353                 m = m_pullup(m, sizeof(struct ip6_hdr));
 354                 if (m == NULL)
 355                         return (ENOMEM);
 356         }
 357         ip6 = (struct ip6_hdr*)m_mtod(m);
 358
 359         if (filter_ref != 0) {
 360                 mtag = m_tag_create(KERNEL_MODULE_TAG_ID,
 361                     KERNEL_TAG_TYPE_IPFILT, sizeof (ipfilter_t), M_NOWAIT, m);
 362                 if (mtag == NULL) {
 363                         m_freem(m);
 364                         return (ENOMEM);
 365                 }
 366                 *(ipfilter_t *)(mtag + 1) = filter_ref;
 367                 m_tag_prepend(m, mtag);
 368         }
 369
 370         if (options != NULL && (options->ippo_flags & IPPOF_MCAST_OPTS) &&
 371             (im6o = ip6_allocmoptions(M_DONTWAIT)) != NULL) {
 372                 im6o->im6o_multicast_ifp = options->ippo_mcast_ifnet;
 373                 im6o->im6o_multicast_hlim = options->ippo_mcast_ttl;
 374                 im6o->im6o_multicast_loop = options->ippo_mcast_loop;
 375         }
 376
 377         if (options != NULL) {
 378                 if (options->ippo_flags & IPPOF_SELECT_SRCIF)
 379                         ip6oa.ip6oa_flags |= IP6OAF_SELECT_SRCIF;
 380                 if (options->ippo_flags & IPPOF_BOUND_IF) {
 381                         ip6oa.ip6oa_flags |= IP6OAF_BOUND_IF;
 382                         ip6oa.ip6oa_boundif = options->ippo_flags >>
 383                             IPPOF_SHIFT_IFSCOPE;
 384                 }
 385                 if (options->ippo_flags & IPPOF_NO_IFT_CELLULAR)
 386                         ip6oa.ip6oa_flags |= IP6OAF_NO_CELLULAR;
 387                 if (options->ippo_flags & IPPOF_BOUND_SRCADDR)
 388                         ip6oa.ip6oa_flags |= IP6OAF_BOUND_SRCADDR;
 389         }
 390
 391         bzero(&ro, sizeof(struct route_in6));
 392
 393         /*
 394          * Send  mbuf and ifscope information. Check for correctness
 395          * of ifscope information is done while searching for a route in
 396          * ip6_output.
 397          */
 398         error = ip6_output(m, NULL, &ro, IPV6_OUTARGS, im6o, NULL, &ip6oa);
 399
 400         /* Release the route */
 401         if (ro.ro_rt)
 402                 rtfree(ro.ro_rt);
 403
 404         if (im6o != NULL)
 405                 IM6O_REMREF(im6o);
 406
 407         return (error);
 408 }
 409 #endif /* INET6 */
 410
 411 errno_t
 412 ipf_inject_output(
 413         mbuf_t data,
 414         ipfilter_t filter_ref,
 415         ipf_pktopts_t options)
 416 {
 417         struct mbuf     *m = (struct mbuf*)data;
 418         u_int8_t        vers;
 419         errno_t         error = 0;
 420
 421         /* Make one byte of the header contiguous in the mbuf */
 422         if (m->m_len < 1) {
 423                 m = m_pullup(m, 1);
 424                 if (m == NULL)
 425                         goto done;
 426         }
 427
 428         vers = (*(u_int8_t*)m_mtod(m)) >> 4;
 429         switch (vers)
 430         {
 431                 case 4:
 432                         error = ipf_injectv4_out(data, filter_ref, options);
 433                         break;
 434 #if INET6
 435                 case 6:
 436                         error = ipf_injectv6_out(data, filter_ref, options);
 437                         break;
 438 #endif
 439                 default:
 440                         m_freem(m);
 441                         error = ENOTSUP;
 442                         break;
 443         }
 444
 445 done:
 446         return error;
 447 }
 448
 449 __private_extern__ ipfilter_t
 450 ipf_get_inject_filter(struct mbuf *m)
 451 {
 452         ipfilter_t filter_ref = 0;
 453         struct m_tag *mtag;
 454
 455         mtag = m_tag_locate(m, KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_IPFILT, NULL);
 456         if (mtag) {
 457                 filter_ref = *(ipfilter_t *)(mtag+1);
 458
 459                 m_tag_delete(m, mtag);
 460         }
 461         return filter_ref;
 462 }
 463
 464 __private_extern__ int
 465 ipf_init(void)
 466 {
 467         int error = 0;
 468         lck_grp_attr_t *grp_attributes = 0;
 469         lck_attr_t *lck_attributes = 0;
 470         lck_grp_t *lck_grp = 0;
 471
 472         grp_attributes = lck_grp_attr_alloc_init();
 473         if (grp_attributes == 0) {
 474                 printf("ipf_init: lck_grp_attr_alloc_init failed\n");
 475                 error = ENOMEM;
 476                 goto done;
 477         }
 478
 479         lck_grp = lck_grp_alloc_init("IP Filter", grp_attributes);
 480         if (lck_grp == 0) {
 481                 printf("ipf_init: lck_grp_alloc_init failed\n");
 482                 error = ENOMEM;
 483                 goto done;
 484         }
 485
 486         lck_attributes = lck_attr_alloc_init();
 487         if (lck_attributes == 0) {
 488                 printf("ipf_init: lck_attr_alloc_init failed\n");
 489                 error = ENOMEM;
 490                 goto done;
 491         }
 492
 493         lck_mtx_init(kipf_lock, lck_grp, lck_attributes);
 494
 495         done:
 496         if (lck_grp) {
 497                 lck_grp_free(lck_grp);
 498                 lck_grp = 0;
 499         }
 500         if (grp_attributes) {
 501                 lck_grp_attr_free(grp_attributes);
 502                 grp_attributes = 0;
 503         }
 504         if (lck_attributes) {
 505                 lck_attr_free(lck_attributes);
 506                 lck_attributes = 0;
 507         }
 508
 509         return error;
 510 }