bsd/netinet/kpi_ipfilter.c

   1 /*
   2  * Copyright (c) 2004-2013 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         routegenid_update();
 140
 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                                 /* This will force TCP to re-evaluate its use of TSO */
 195                                 OSAddAtomic(-1, &kipf_count);
 196                                 routegenid_update();
 197
 198                         }
 199                         return 0;
 200                 }
 201         }
 202         lck_mtx_unlock(kipf_lock);
 203
 204         return ENOENT;
 205 }
 206
 207 int log_for_en1 = 0;
 208
 209 errno_t
 210 ipf_inject_input(
 211         mbuf_t data,
 212         ipfilter_t filter_ref)
 213 {
 214         struct mbuf     *m = (struct mbuf*)data;
 215         struct m_tag *mtag = 0;
 216         struct ip *ip = mtod(m, struct ip *);
 217         u_int8_t        vers;
 218         int hlen;
 219         errno_t error = 0;
 220         protocol_family_t proto;
 221
 222         vers = IP_VHL_V(ip->ip_vhl);
 223
 224         switch (vers) {
 225                 case 4:
 226                         proto = PF_INET;
 227                         break;
 228                 case 6:
 229                         proto = PF_INET6;
 230                         break;
 231                 default:
 232                         error = ENOTSUP;
 233                         goto done;
 234         }
 235
 236         if (filter_ref == 0 && m->m_pkthdr.rcvif == 0) {
 237                 m->m_pkthdr.rcvif = lo_ifp;
 238                 m->m_pkthdr.csum_data = 0;
 239                 m->m_pkthdr.csum_flags = 0;
 240                 if (vers == 4) {
 241                         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 242                         ip->ip_sum = 0;
 243                         ip->ip_sum = in_cksum(m, hlen);
 244                 }
 245         }
 246         if (filter_ref != 0) {
 247                 mtag = m_tag_create(KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_IPFILT,
 248                                                    sizeof (ipfilter_t), M_NOWAIT, m);
 249                 if (mtag == NULL) {
 250                         error = ENOMEM;
 251                         goto done;
 252                 }
 253                 *(ipfilter_t*)(mtag+1) = filter_ref;
 254                 m_tag_prepend(m, mtag);
 255         }
 256
 257         error = proto_inject(proto, data);
 258
 259 done:
 260         return error;
 261 }
 262
 263 static errno_t
 264 ipf_injectv4_out(mbuf_t data, ipfilter_t filter_ref, ipf_pktopts_t options)
 265 {
 266         struct route ro;
 267         struct ip       *ip;
 268         struct mbuf     *m = (struct mbuf*)data;
 269         errno_t error = 0;
 270         struct m_tag *mtag = NULL;
 271         struct ip_moptions *imo = NULL;
 272         struct ip_out_args ipoa = { IFSCOPE_NONE, { 0 }, 0, 0 };
 273
 274         /* Make the IP header contiguous in the mbuf */
 275         if ((size_t)m->m_len < sizeof (struct ip)) {
 276                 m = m_pullup(m, sizeof (struct ip));
 277                 if (m == NULL)
 278                         return (ENOMEM);
 279         }
 280         ip = (struct ip *)m_mtod(m);
 281
 282         if (filter_ref != 0) {
 283                 mtag = m_tag_create(KERNEL_MODULE_TAG_ID,
 284                     KERNEL_TAG_TYPE_IPFILT, sizeof (ipfilter_t), M_NOWAIT, m);
 285                 if (mtag == NULL) {
 286                         m_freem(m);
 287                         return (ENOMEM);
 288                 }
 289                 *(ipfilter_t *)(mtag + 1) = filter_ref;
 290                 m_tag_prepend(m, mtag);
 291         }
 292
 293         if (options != NULL && (options->ippo_flags & IPPOF_MCAST_OPTS) &&
 294             (imo = ip_allocmoptions(M_DONTWAIT)) != NULL) {
 295                 imo->imo_multicast_ifp = options->ippo_mcast_ifnet;
 296                 imo->imo_multicast_ttl = options->ippo_mcast_ttl;
 297                 imo->imo_multicast_loop = options->ippo_mcast_loop;
 298         }
 299
 300         if (options != NULL) {
 301                 if (options->ippo_flags & IPPOF_SELECT_SRCIF)
 302                         ipoa.ipoa_flags |= IPOAF_SELECT_SRCIF;
 303                 if (options->ippo_flags & IPPOF_BOUND_IF) {
 304                         ipoa.ipoa_flags |= IPOAF_BOUND_IF;
 305                         ipoa.ipoa_boundif = options->ippo_flags >>
 306                             IPPOF_SHIFT_IFSCOPE;
 307                 }
 308                 if (options->ippo_flags & IPPOF_NO_IFT_CELLULAR)
 309                         ipoa.ipoa_flags |= IPOAF_NO_CELLULAR;
 310                 if (options->ippo_flags & IPPOF_BOUND_SRCADDR)
 311                         ipoa.ipoa_flags |= IPOAF_BOUND_SRCADDR;
 312         }
 313
 314         bzero(&ro, sizeof(struct route));
 315
 316         /* Put ip_len and ip_off in host byte order, ip_output expects that */
 317
 318 #if BYTE_ORDER != BIG_ENDIAN
 319         NTOHS(ip->ip_len);
 320         NTOHS(ip->ip_off);
 321 #endif
 322
 323         /* Send; enforce source interface selection via IP_OUTARGS flag */
 324         error = ip_output(m, NULL, &ro,
 325             IP_ALLOWBROADCAST | IP_RAWOUTPUT | IP_OUTARGS, imo, &ipoa);
 326
 327         /* Release the route */
 328         ROUTE_RELEASE(&ro);
 329
 330         if (imo != NULL)
 331                 IMO_REMREF(imo);
 332
 333         return (error);
 334 }
 335
 336 #if INET6
 337 static errno_t
 338 ipf_injectv6_out(mbuf_t data, ipfilter_t filter_ref, ipf_pktopts_t options)
 339 {
 340         struct route_in6 ro;
 341         struct ip6_hdr  *ip6;
 342         struct mbuf     *m = (struct mbuf*)data;
 343         errno_t error = 0;
 344         struct m_tag *mtag = NULL;
 345         struct ip6_moptions *im6o = NULL;
 346         struct ip6_out_args ip6oa = { IFSCOPE_NONE, { 0 }, 0, 0 };
 347
 348         /* Make the IP header contiguous in the mbuf */
 349         if ((size_t)m->m_len < sizeof(struct ip6_hdr)) {
 350                 m = m_pullup(m, sizeof(struct ip6_hdr));
 351                 if (m == NULL)
 352                         return (ENOMEM);
 353         }
 354         ip6 = (struct ip6_hdr*)m_mtod(m);
 355
 356         if (filter_ref != 0) {
 357                 mtag = m_tag_create(KERNEL_MODULE_TAG_ID,
 358                     KERNEL_TAG_TYPE_IPFILT, sizeof (ipfilter_t), M_NOWAIT, m);
 359                 if (mtag == NULL) {
 360                         m_freem(m);
 361                         return (ENOMEM);
 362                 }
 363                 *(ipfilter_t *)(mtag + 1) = filter_ref;
 364                 m_tag_prepend(m, mtag);
 365         }
 366
 367         if (options != NULL && (options->ippo_flags & IPPOF_MCAST_OPTS) &&
 368             (im6o = ip6_allocmoptions(M_DONTWAIT)) != NULL) {
 369                 im6o->im6o_multicast_ifp = options->ippo_mcast_ifnet;
 370                 im6o->im6o_multicast_hlim = options->ippo_mcast_ttl;
 371                 im6o->im6o_multicast_loop = options->ippo_mcast_loop;
 372         }
 373
 374         if (options != NULL) {
 375                 if (options->ippo_flags & IPPOF_SELECT_SRCIF)
 376                         ip6oa.ip6oa_flags |= IP6OAF_SELECT_SRCIF;
 377                 if (options->ippo_flags & IPPOF_BOUND_IF) {
 378                         ip6oa.ip6oa_flags |= IP6OAF_BOUND_IF;
 379                         ip6oa.ip6oa_boundif = options->ippo_flags >>
 380                             IPPOF_SHIFT_IFSCOPE;
 381                 }
 382                 if (options->ippo_flags & IPPOF_NO_IFT_CELLULAR)
 383                         ip6oa.ip6oa_flags |= IP6OAF_NO_CELLULAR;
 384                 if (options->ippo_flags & IPPOF_BOUND_SRCADDR)
 385                         ip6oa.ip6oa_flags |= IP6OAF_BOUND_SRCADDR;
 386         }
 387
 388         bzero(&ro, sizeof(struct route_in6));
 389
 390         /*
 391          * Send  mbuf and ifscope information. Check for correctness
 392          * of ifscope information is done while searching for a route in
 393          * ip6_output.
 394          */
 395         error = ip6_output(m, NULL, &ro, IPV6_OUTARGS, im6o, NULL, &ip6oa);
 396
 397         /* Release the route */
 398         ROUTE_RELEASE(&ro);
 399
 400         if (im6o != NULL)
 401                 IM6O_REMREF(im6o);
 402
 403         return (error);
 404 }
 405 #endif /* INET6 */
 406
 407 errno_t
 408 ipf_inject_output(
 409         mbuf_t data,
 410         ipfilter_t filter_ref,
 411         ipf_pktopts_t options)
 412 {
 413         struct mbuf     *m = (struct mbuf*)data;
 414         u_int8_t        vers;
 415         errno_t         error = 0;
 416
 417         /* Make one byte of the header contiguous in the mbuf */
 418         if (m->m_len < 1) {
 419                 m = m_pullup(m, 1);
 420                 if (m == NULL)
 421                         goto done;
 422         }
 423
 424         vers = (*(u_int8_t*)m_mtod(m)) >> 4;
 425         switch (vers)
 426         {
 427                 case 4:
 428                         error = ipf_injectv4_out(data, filter_ref, options);
 429                         break;
 430 #if INET6
 431                 case 6:
 432                         error = ipf_injectv6_out(data, filter_ref, options);
 433                         break;
 434 #endif
 435                 default:
 436                         m_freem(m);
 437                         error = ENOTSUP;
 438                         break;
 439         }
 440
 441 done:
 442         return error;
 443 }
 444
 445 __private_extern__ ipfilter_t
 446 ipf_get_inject_filter(struct mbuf *m)
 447 {
 448         ipfilter_t filter_ref = 0;
 449         struct m_tag *mtag;
 450
 451         mtag = m_tag_locate(m, KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_IPFILT, NULL);
 452         if (mtag) {
 453                 filter_ref = *(ipfilter_t *)(mtag+1);
 454
 455                 m_tag_delete(m, mtag);
 456         }
 457         return filter_ref;
 458 }
 459
 460 __private_extern__ int
 461 ipf_init(void)
 462 {
 463         int error = 0;
 464         lck_grp_attr_t *grp_attributes = 0;
 465         lck_attr_t *lck_attributes = 0;
 466         lck_grp_t *lck_grp = 0;
 467
 468         grp_attributes = lck_grp_attr_alloc_init();
 469         if (grp_attributes == 0) {
 470                 printf("ipf_init: lck_grp_attr_alloc_init failed\n");
 471                 error = ENOMEM;
 472                 goto done;
 473         }
 474
 475         lck_grp = lck_grp_alloc_init("IP Filter", grp_attributes);
 476         if (lck_grp == 0) {
 477                 printf("ipf_init: lck_grp_alloc_init failed\n");
 478                 error = ENOMEM;
 479                 goto done;
 480         }
 481
 482         lck_attributes = lck_attr_alloc_init();
 483         if (lck_attributes == 0) {
 484                 printf("ipf_init: lck_attr_alloc_init failed\n");
 485                 error = ENOMEM;
 486                 goto done;
 487         }
 488
 489         lck_mtx_init(kipf_lock, lck_grp, lck_attributes);
 490
 491         done:
 492         if (lck_grp) {
 493                 lck_grp_free(lck_grp);
 494                 lck_grp = 0;
 495         }
 496         if (grp_attributes) {
 497                 lck_grp_attr_free(grp_attributes);
 498                 grp_attributes = 0;
 499         }
 500         if (lck_attributes) {
 501                 lck_attr_free(lck_attributes);
 502                 lck_attributes = 0;
 503         }
 504
 505         return error;
 506 }