1 // SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 2 /* gw.c - CAN frame Gateway/Router/Bridge with netlink interface 3 * 4 * Copyright (c) 2019 Volkswagen Group Electronic Research 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of Volkswagen nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * Alternatively, provided that this notice is retained in full, this 20 * software may be distributed under the terms of the GNU General 21 * Public License ("GPL") version 2, in which case the provisions of the 22 * GPL apply INSTEAD OF those given above. 23 * 24 * The provided data structures and external interfaces from this code 25 * are not restricted to be used by modules with a GPL compatible license. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 30 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 31 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 32 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 33 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 37 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 38 * DAMAGE. 39 * 40 */ 41 42 #include <linux/module.h> 43 #include <linux/init.h> 44 #include <linux/types.h> 45 #include <linux/kernel.h> 46 #include <linux/list.h> 47 #include <linux/spinlock.h> 48 #include <linux/rcupdate.h> 49 #include <linux/rculist.h> 50 #include <linux/net.h> 51 #include <linux/netdevice.h> 52 #include <linux/if_arp.h> 53 #include <linux/skbuff.h> 54 #include <linux/can.h> 55 #include <linux/can/core.h> 56 #include <linux/can/skb.h> 57 #include <linux/can/gw.h> 58 #include <net/rtnetlink.h> 59 #include <net/net_namespace.h> 60 #include <net/sock.h> 61 62 #define CAN_GW_VERSION "20190810" 63 #define CAN_GW_NAME "can-gw" 64 65 MODULE_DESCRIPTION("PF_CAN netlink gateway"); 66 MODULE_LICENSE("Dual BSD/GPL"); 67 MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>"); 68 MODULE_ALIAS(CAN_GW_NAME); 69 70 #define CGW_MIN_HOPS 1 71 #define CGW_MAX_HOPS 6 72 #define CGW_DEFAULT_HOPS 1 73 74 static unsigned int max_hops __read_mostly = CGW_DEFAULT_HOPS; 75 module_param(max_hops, uint, 0444); 76 MODULE_PARM_DESC(max_hops, 77 "maximum " CAN_GW_NAME " routing hops for CAN frames " 78 "(valid values: " __stringify(CGW_MIN_HOPS) "-" 79 __stringify(CGW_MAX_HOPS) " hops, " 80 "default: " __stringify(CGW_DEFAULT_HOPS) ")"); 81 82 static struct notifier_block notifier; 83 static struct kmem_cache *cgw_cache __read_mostly; 84 85 /* structure that contains the (on-the-fly) CAN frame modifications */ 86 struct cf_mod { 87 struct { 88 struct canfd_frame and; 89 struct canfd_frame or; 90 struct canfd_frame xor; 91 struct canfd_frame set; 92 } modframe; 93 struct { 94 u8 and; 95 u8 or; 96 u8 xor; 97 u8 set; 98 } modtype; 99 void (*modfunc[MAX_MODFUNCTIONS])(struct canfd_frame *cf, 100 struct cf_mod *mod); 101 102 /* CAN frame checksum calculation after CAN frame modifications */ 103 struct { 104 struct cgw_csum_xor xor; 105 struct cgw_csum_crc8 crc8; 106 } csum; 107 struct { 108 void (*xor)(struct canfd_frame *cf, 109 struct cgw_csum_xor *xor); 110 void (*crc8)(struct canfd_frame *cf, 111 struct cgw_csum_crc8 *crc8); 112 } csumfunc; 113 u32 uid; 114 }; 115 116 /* So far we just support CAN -> CAN routing and frame modifications. 117 * 118 * The internal can_can_gw structure contains data and attributes for 119 * a CAN -> CAN gateway job. 120 */ 121 struct can_can_gw { 122 struct can_filter filter; 123 int src_idx; 124 int dst_idx; 125 }; 126 127 /* list entry for CAN gateways jobs */ 128 struct cgw_job { 129 struct hlist_node list; 130 struct rcu_head rcu; 131 u32 handled_frames; 132 u32 dropped_frames; 133 u32 deleted_frames; 134 struct cf_mod mod; 135 union { 136 /* CAN frame data source */ 137 struct net_device *dev; 138 } src; 139 union { 140 /* CAN frame data destination */ 141 struct net_device *dev; 142 } dst; 143 union { 144 struct can_can_gw ccgw; 145 /* tbc */ 146 }; 147 u8 gwtype; 148 u8 limit_hops; 149 u16 flags; 150 }; 151 152 /* modification functions that are invoked in the hot path in can_can_gw_rcv */ 153 154 #define MODFUNC(func, op) static void func(struct canfd_frame *cf, \ 155 struct cf_mod *mod) { op ; } 156 157 MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id) 158 MODFUNC(mod_and_len, cf->len &= mod->modframe.and.len) 159 MODFUNC(mod_and_flags, cf->flags &= mod->modframe.and.flags) 160 MODFUNC(mod_and_data, *(u64 *)cf->data &= *(u64 *)mod->modframe.and.data) 161 MODFUNC(mod_or_id, cf->can_id |= mod->modframe.or.can_id) 162 MODFUNC(mod_or_len, cf->len |= mod->modframe.or.len) 163 MODFUNC(mod_or_flags, cf->flags |= mod->modframe.or.flags) 164 MODFUNC(mod_or_data, *(u64 *)cf->data |= *(u64 *)mod->modframe.or.data) 165 MODFUNC(mod_xor_id, cf->can_id ^= mod->modframe.xor.can_id) 166 MODFUNC(mod_xor_len, cf->len ^= mod->modframe.xor.len) 167 MODFUNC(mod_xor_flags, cf->flags ^= mod->modframe.xor.flags) 168 MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data) 169 MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id) 170 MODFUNC(mod_set_len, cf->len = mod->modframe.set.len) 171 MODFUNC(mod_set_flags, cf->flags = mod->modframe.set.flags) 172 MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data) 173 174 static void mod_and_fddata(struct canfd_frame *cf, struct cf_mod *mod) 175 { 176 int i; 177 178 for (i = 0; i < CANFD_MAX_DLEN; i += 8) 179 *(u64 *)(cf->data + i) &= *(u64 *)(mod->modframe.and.data + i); 180 } 181 182 static void mod_or_fddata(struct canfd_frame *cf, struct cf_mod *mod) 183 { 184 int i; 185 186 for (i = 0; i < CANFD_MAX_DLEN; i += 8) 187 *(u64 *)(cf->data + i) |= *(u64 *)(mod->modframe.or.data + i); 188 } 189 190 static void mod_xor_fddata(struct canfd_frame *cf, struct cf_mod *mod) 191 { 192 int i; 193 194 for (i = 0; i < CANFD_MAX_DLEN; i += 8) 195 *(u64 *)(cf->data + i) ^= *(u64 *)(mod->modframe.xor.data + i); 196 } 197 198 static void mod_set_fddata(struct canfd_frame *cf, struct cf_mod *mod) 199 { 200 memcpy(cf->data, mod->modframe.set.data, CANFD_MAX_DLEN); 201 } 202 203 static void canframecpy(struct canfd_frame *dst, struct can_frame *src) 204 { 205 /* Copy the struct members separately to ensure that no uninitialized 206 * data are copied in the 3 bytes hole of the struct. This is needed 207 * to make easy compares of the data in the struct cf_mod. 208 */ 209 210 dst->can_id = src->can_id; 211 dst->len = src->can_dlc; 212 *(u64 *)dst->data = *(u64 *)src->data; 213 } 214 215 static void canfdframecpy(struct canfd_frame *dst, struct canfd_frame *src) 216 { 217 /* Copy the struct members separately to ensure that no uninitialized 218 * data are copied in the 2 bytes hole of the struct. This is needed 219 * to make easy compares of the data in the struct cf_mod. 220 */ 221 222 dst->can_id = src->can_id; 223 dst->flags = src->flags; 224 dst->len = src->len; 225 memcpy(dst->data, src->data, CANFD_MAX_DLEN); 226 } 227 228 static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re, struct rtcanmsg *r) 229 { 230 s8 dlen = CAN_MAX_DLEN; 231 232 if (r->flags & CGW_FLAGS_CAN_FD) 233 dlen = CANFD_MAX_DLEN; 234 235 /* absolute dlc values 0 .. 7 => 0 .. 7, e.g. data [0] 236 * relative to received dlc -1 .. -8 : 237 * e.g. for received dlc = 8 238 * -1 => index = 7 (data[7]) 239 * -3 => index = 5 (data[5]) 240 * -8 => index = 0 (data[0]) 241 */ 242 243 if (fr >= -dlen && fr < dlen && 244 to >= -dlen && to < dlen && 245 re >= -dlen && re < dlen) 246 return 0; 247 else 248 return -EINVAL; 249 } 250 251 static inline int calc_idx(int idx, int rx_len) 252 { 253 if (idx < 0) 254 return rx_len + idx; 255 else 256 return idx; 257 } 258 259 static void cgw_csum_xor_rel(struct canfd_frame *cf, struct cgw_csum_xor *xor) 260 { 261 int from = calc_idx(xor->from_idx, cf->len); 262 int to = calc_idx(xor->to_idx, cf->len); 263 int res = calc_idx(xor->result_idx, cf->len); 264 u8 val = xor->init_xor_val; 265 int i; 266 267 if (from < 0 || to < 0 || res < 0) 268 return; 269 270 if (from <= to) { 271 for (i = from; i <= to; i++) 272 val ^= cf->data[i]; 273 } else { 274 for (i = from; i >= to; i--) 275 val ^= cf->data[i]; 276 } 277 278 cf->data[res] = val; 279 } 280 281 static void cgw_csum_xor_pos(struct canfd_frame *cf, struct cgw_csum_xor *xor) 282 { 283 u8 val = xor->init_xor_val; 284 int i; 285 286 for (i = xor->from_idx; i <= xor->to_idx; i++) 287 val ^= cf->data[i]; 288 289 cf->data[xor->result_idx] = val; 290 } 291 292 static void cgw_csum_xor_neg(struct canfd_frame *cf, struct cgw_csum_xor *xor) 293 { 294 u8 val = xor->init_xor_val; 295 int i; 296 297 for (i = xor->from_idx; i >= xor->to_idx; i--) 298 val ^= cf->data[i]; 299 300 cf->data[xor->result_idx] = val; 301 } 302 303 static void cgw_csum_crc8_rel(struct canfd_frame *cf, 304 struct cgw_csum_crc8 *crc8) 305 { 306 int from = calc_idx(crc8->from_idx, cf->len); 307 int to = calc_idx(crc8->to_idx, cf->len); 308 int res = calc_idx(crc8->result_idx, cf->len); 309 u8 crc = crc8->init_crc_val; 310 int i; 311 312 if (from < 0 || to < 0 || res < 0) 313 return; 314 315 if (from <= to) { 316 for (i = crc8->from_idx; i <= crc8->to_idx; i++) 317 crc = crc8->crctab[crc ^ cf->data[i]]; 318 } else { 319 for (i = crc8->from_idx; i >= crc8->to_idx; i--) 320 crc = crc8->crctab[crc ^ cf->data[i]]; 321 } 322 323 switch (crc8->profile) { 324 case CGW_CRC8PRF_1U8: 325 crc = crc8->crctab[crc ^ crc8->profile_data[0]]; 326 break; 327 328 case CGW_CRC8PRF_16U8: 329 crc = crc8->crctab[crc ^ crc8->profile_data[cf->data[1] & 0xF]]; 330 break; 331 332 case CGW_CRC8PRF_SFFID_XOR: 333 crc = crc8->crctab[crc ^ (cf->can_id & 0xFF) ^ 334 (cf->can_id >> 8 & 0xFF)]; 335 break; 336 } 337 338 cf->data[crc8->result_idx] = crc ^ crc8->final_xor_val; 339 } 340 341 static void cgw_csum_crc8_pos(struct canfd_frame *cf, 342 struct cgw_csum_crc8 *crc8) 343 { 344 u8 crc = crc8->init_crc_val; 345 int i; 346 347 for (i = crc8->from_idx; i <= crc8->to_idx; i++) 348 crc = crc8->crctab[crc ^ cf->data[i]]; 349 350 switch (crc8->profile) { 351 case CGW_CRC8PRF_1U8: 352 crc = crc8->crctab[crc ^ crc8->profile_data[0]]; 353 break; 354 355 case CGW_CRC8PRF_16U8: 356 crc = crc8->crctab[crc ^ crc8->profile_data[cf->data[1] & 0xF]]; 357 break; 358 359 case CGW_CRC8PRF_SFFID_XOR: 360 crc = crc8->crctab[crc ^ (cf->can_id & 0xFF) ^ 361 (cf->can_id >> 8 & 0xFF)]; 362 break; 363 } 364 365 cf->data[crc8->result_idx] = crc ^ crc8->final_xor_val; 366 } 367 368 static void cgw_csum_crc8_neg(struct canfd_frame *cf, 369 struct cgw_csum_crc8 *crc8) 370 { 371 u8 crc = crc8->init_crc_val; 372 int i; 373 374 for (i = crc8->from_idx; i >= crc8->to_idx; i--) 375 crc = crc8->crctab[crc ^ cf->data[i]]; 376 377 switch (crc8->profile) { 378 case CGW_CRC8PRF_1U8: 379 crc = crc8->crctab[crc ^ crc8->profile_data[0]]; 380 break; 381 382 case CGW_CRC8PRF_16U8: 383 crc = crc8->crctab[crc ^ crc8->profile_data[cf->data[1] & 0xF]]; 384 break; 385 386 case CGW_CRC8PRF_SFFID_XOR: 387 crc = crc8->crctab[crc ^ (cf->can_id & 0xFF) ^ 388 (cf->can_id >> 8 & 0xFF)]; 389 break; 390 } 391 392 cf->data[crc8->result_idx] = crc ^ crc8->final_xor_val; 393 } 394 395 /* the receive & process & send function */ 396 static void can_can_gw_rcv(struct sk_buff *skb, void *data) 397 { 398 struct cgw_job *gwj = (struct cgw_job *)data; 399 struct canfd_frame *cf; 400 struct sk_buff *nskb; 401 int modidx = 0; 402 403 /* process strictly Classic CAN or CAN FD frames */ 404 if (gwj->flags & CGW_FLAGS_CAN_FD) { 405 if (skb->len != CANFD_MTU) 406 return; 407 } else { 408 if (skb->len != CAN_MTU) 409 return; 410 } 411 412 /* Do not handle CAN frames routed more than 'max_hops' times. 413 * In general we should never catch this delimiter which is intended 414 * to cover a misconfiguration protection (e.g. circular CAN routes). 415 * 416 * The Controller Area Network controllers only accept CAN frames with 417 * correct CRCs - which are not visible in the controller registers. 418 * According to skbuff.h documentation the csum_start element for IP 419 * checksums is undefined/unused when ip_summed == CHECKSUM_UNNECESSARY. 420 * Only CAN skbs can be processed here which already have this property. 421 */ 422 423 #define cgw_hops(skb) ((skb)->csum_start) 424 425 BUG_ON(skb->ip_summed != CHECKSUM_UNNECESSARY); 426 427 if (cgw_hops(skb) >= max_hops) { 428 /* indicate deleted frames due to misconfiguration */ 429 gwj->deleted_frames++; 430 return; 431 } 432 433 if (!(gwj->dst.dev->flags & IFF_UP)) { 434 gwj->dropped_frames++; 435 return; 436 } 437 438 /* is sending the skb back to the incoming interface not allowed? */ 439 if (!(gwj->flags & CGW_FLAGS_CAN_IIF_TX_OK) && 440 can_skb_prv(skb)->ifindex == gwj->dst.dev->ifindex) 441 return; 442 443 /* clone the given skb, which has not been done in can_rcv() 444 * 445 * When there is at least one modification function activated, 446 * we need to copy the skb as we want to modify skb->data. 447 */ 448 if (gwj->mod.modfunc[0]) 449 nskb = skb_copy(skb, GFP_ATOMIC); 450 else 451 nskb = skb_clone(skb, GFP_ATOMIC); 452 453 if (!nskb) { 454 gwj->dropped_frames++; 455 return; 456 } 457 458 /* put the incremented hop counter in the cloned skb */ 459 cgw_hops(nskb) = cgw_hops(skb) + 1; 460 461 /* first processing of this CAN frame -> adjust to private hop limit */ 462 if (gwj->limit_hops && cgw_hops(nskb) == 1) 463 cgw_hops(nskb) = max_hops - gwj->limit_hops + 1; 464 465 nskb->dev = gwj->dst.dev; 466 467 /* pointer to modifiable CAN frame */ 468 cf = (struct canfd_frame *)nskb->data; 469 470 /* perform preprocessed modification functions if there are any */ 471 while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx]) 472 (*gwj->mod.modfunc[modidx++])(cf, &gwj->mod); 473 474 /* Has the CAN frame been modified? */ 475 if (modidx) { 476 /* get available space for the processed CAN frame type */ 477 int max_len = nskb->len - offsetof(struct canfd_frame, data); 478 479 /* dlc may have changed, make sure it fits to the CAN frame */ 480 if (cf->len > max_len) { 481 /* delete frame due to misconfiguration */ 482 gwj->deleted_frames++; 483 kfree_skb(nskb); 484 return; 485 } 486 487 /* check for checksum updates */ 488 if (gwj->mod.csumfunc.crc8) 489 (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8); 490 491 if (gwj->mod.csumfunc.xor) 492 (*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor); 493 } 494 495 /* clear the skb timestamp if not configured the other way */ 496 if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP)) 497 nskb->tstamp = 0; 498 499 /* send to netdevice */ 500 if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO)) 501 gwj->dropped_frames++; 502 else 503 gwj->handled_frames++; 504 } 505 506 static inline int cgw_register_filter(struct net *net, struct cgw_job *gwj) 507 { 508 return can_rx_register(net, gwj->src.dev, gwj->ccgw.filter.can_id, 509 gwj->ccgw.filter.can_mask, can_can_gw_rcv, 510 gwj, "gw", NULL); 511 } 512 513 static inline void cgw_unregister_filter(struct net *net, struct cgw_job *gwj) 514 { 515 can_rx_unregister(net, gwj->src.dev, gwj->ccgw.filter.can_id, 516 gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj); 517 } 518 519 static int cgw_notifier(struct notifier_block *nb, 520 unsigned long msg, void *ptr) 521 { 522 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 523 struct net *net = dev_net(dev); 524 525 if (dev->type != ARPHRD_CAN) 526 return NOTIFY_DONE; 527 528 if (msg == NETDEV_UNREGISTER) { 529 struct cgw_job *gwj = NULL; 530 struct hlist_node *nx; 531 532 ASSERT_RTNL(); 533 534 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) { 535 if (gwj->src.dev == dev || gwj->dst.dev == dev) { 536 hlist_del(&gwj->list); 537 cgw_unregister_filter(net, gwj); 538 kmem_cache_free(cgw_cache, gwj); 539 } 540 } 541 } 542 543 return NOTIFY_DONE; 544 } 545 546 static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type, 547 u32 pid, u32 seq, int flags) 548 { 549 struct rtcanmsg *rtcan; 550 struct nlmsghdr *nlh; 551 552 nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags); 553 if (!nlh) 554 return -EMSGSIZE; 555 556 rtcan = nlmsg_data(nlh); 557 rtcan->can_family = AF_CAN; 558 rtcan->gwtype = gwj->gwtype; 559 rtcan->flags = gwj->flags; 560 561 /* add statistics if available */ 562 563 if (gwj->handled_frames) { 564 if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0) 565 goto cancel; 566 } 567 568 if (gwj->dropped_frames) { 569 if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0) 570 goto cancel; 571 } 572 573 if (gwj->deleted_frames) { 574 if (nla_put_u32(skb, CGW_DELETED, gwj->deleted_frames) < 0) 575 goto cancel; 576 } 577 578 /* check non default settings of attributes */ 579 580 if (gwj->limit_hops) { 581 if (nla_put_u8(skb, CGW_LIM_HOPS, gwj->limit_hops) < 0) 582 goto cancel; 583 } 584 585 if (gwj->flags & CGW_FLAGS_CAN_FD) { 586 struct cgw_fdframe_mod mb; 587 588 if (gwj->mod.modtype.and) { 589 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf)); 590 mb.modtype = gwj->mod.modtype.and; 591 if (nla_put(skb, CGW_FDMOD_AND, sizeof(mb), &mb) < 0) 592 goto cancel; 593 } 594 595 if (gwj->mod.modtype.or) { 596 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf)); 597 mb.modtype = gwj->mod.modtype.or; 598 if (nla_put(skb, CGW_FDMOD_OR, sizeof(mb), &mb) < 0) 599 goto cancel; 600 } 601 602 if (gwj->mod.modtype.xor) { 603 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf)); 604 mb.modtype = gwj->mod.modtype.xor; 605 if (nla_put(skb, CGW_FDMOD_XOR, sizeof(mb), &mb) < 0) 606 goto cancel; 607 } 608 609 if (gwj->mod.modtype.set) { 610 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf)); 611 mb.modtype = gwj->mod.modtype.set; 612 if (nla_put(skb, CGW_FDMOD_SET, sizeof(mb), &mb) < 0) 613 goto cancel; 614 } 615 } else { 616 struct cgw_frame_mod mb; 617 618 if (gwj->mod.modtype.and) { 619 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf)); 620 mb.modtype = gwj->mod.modtype.and; 621 if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0) 622 goto cancel; 623 } 624 625 if (gwj->mod.modtype.or) { 626 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf)); 627 mb.modtype = gwj->mod.modtype.or; 628 if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0) 629 goto cancel; 630 } 631 632 if (gwj->mod.modtype.xor) { 633 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf)); 634 mb.modtype = gwj->mod.modtype.xor; 635 if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0) 636 goto cancel; 637 } 638 639 if (gwj->mod.modtype.set) { 640 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf)); 641 mb.modtype = gwj->mod.modtype.set; 642 if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0) 643 goto cancel; 644 } 645 } 646 647 if (gwj->mod.uid) { 648 if (nla_put_u32(skb, CGW_MOD_UID, gwj->mod.uid) < 0) 649 goto cancel; 650 } 651 652 if (gwj->mod.csumfunc.crc8) { 653 if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN, 654 &gwj->mod.csum.crc8) < 0) 655 goto cancel; 656 } 657 658 if (gwj->mod.csumfunc.xor) { 659 if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN, 660 &gwj->mod.csum.xor) < 0) 661 goto cancel; 662 } 663 664 if (gwj->gwtype == CGW_TYPE_CAN_CAN) { 665 if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) { 666 if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter), 667 &gwj->ccgw.filter) < 0) 668 goto cancel; 669 } 670 671 if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0) 672 goto cancel; 673 674 if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0) 675 goto cancel; 676 } 677 678 nlmsg_end(skb, nlh); 679 return 0; 680 681 cancel: 682 nlmsg_cancel(skb, nlh); 683 return -EMSGSIZE; 684 } 685 686 /* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */ 687 static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb) 688 { 689 struct net *net = sock_net(skb->sk); 690 struct cgw_job *gwj = NULL; 691 int idx = 0; 692 int s_idx = cb->args[0]; 693 694 rcu_read_lock(); 695 hlist_for_each_entry_rcu(gwj, &net->can.cgw_list, list) { 696 if (idx < s_idx) 697 goto cont; 698 699 if (cgw_put_job(skb, gwj, RTM_NEWROUTE, 700 NETLINK_CB(cb->skb).portid, 701 cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0) 702 break; 703 cont: 704 idx++; 705 } 706 rcu_read_unlock(); 707 708 cb->args[0] = idx; 709 710 return skb->len; 711 } 712 713 static const struct nla_policy cgw_policy[CGW_MAX + 1] = { 714 [CGW_MOD_AND] = { .len = sizeof(struct cgw_frame_mod) }, 715 [CGW_MOD_OR] = { .len = sizeof(struct cgw_frame_mod) }, 716 [CGW_MOD_XOR] = { .len = sizeof(struct cgw_frame_mod) }, 717 [CGW_MOD_SET] = { .len = sizeof(struct cgw_frame_mod) }, 718 [CGW_CS_XOR] = { .len = sizeof(struct cgw_csum_xor) }, 719 [CGW_CS_CRC8] = { .len = sizeof(struct cgw_csum_crc8) }, 720 [CGW_SRC_IF] = { .type = NLA_U32 }, 721 [CGW_DST_IF] = { .type = NLA_U32 }, 722 [CGW_FILTER] = { .len = sizeof(struct can_filter) }, 723 [CGW_LIM_HOPS] = { .type = NLA_U8 }, 724 [CGW_MOD_UID] = { .type = NLA_U32 }, 725 [CGW_FDMOD_AND] = { .len = sizeof(struct cgw_fdframe_mod) }, 726 [CGW_FDMOD_OR] = { .len = sizeof(struct cgw_fdframe_mod) }, 727 [CGW_FDMOD_XOR] = { .len = sizeof(struct cgw_fdframe_mod) }, 728 [CGW_FDMOD_SET] = { .len = sizeof(struct cgw_fdframe_mod) }, 729 }; 730 731 /* check for common and gwtype specific attributes */ 732 static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod, 733 u8 gwtype, void *gwtypeattr, u8 *limhops) 734 { 735 struct nlattr *tb[CGW_MAX + 1]; 736 struct rtcanmsg *r = nlmsg_data(nlh); 737 int modidx = 0; 738 int err = 0; 739 740 /* initialize modification & checksum data space */ 741 memset(mod, 0, sizeof(*mod)); 742 743 err = nlmsg_parse_deprecated(nlh, sizeof(struct rtcanmsg), tb, 744 CGW_MAX, cgw_policy, NULL); 745 if (err < 0) 746 return err; 747 748 if (tb[CGW_LIM_HOPS]) { 749 *limhops = nla_get_u8(tb[CGW_LIM_HOPS]); 750 751 if (*limhops < 1 || *limhops > max_hops) 752 return -EINVAL; 753 } 754 755 /* check for AND/OR/XOR/SET modifications */ 756 if (r->flags & CGW_FLAGS_CAN_FD) { 757 struct cgw_fdframe_mod mb; 758 759 if (tb[CGW_FDMOD_AND]) { 760 nla_memcpy(&mb, tb[CGW_FDMOD_AND], CGW_FDMODATTR_LEN); 761 762 canfdframecpy(&mod->modframe.and, &mb.cf); 763 mod->modtype.and = mb.modtype; 764 765 if (mb.modtype & CGW_MOD_ID) 766 mod->modfunc[modidx++] = mod_and_id; 767 768 if (mb.modtype & CGW_MOD_LEN) 769 mod->modfunc[modidx++] = mod_and_len; 770 771 if (mb.modtype & CGW_MOD_FLAGS) 772 mod->modfunc[modidx++] = mod_and_flags; 773 774 if (mb.modtype & CGW_MOD_DATA) 775 mod->modfunc[modidx++] = mod_and_fddata; 776 } 777 778 if (tb[CGW_FDMOD_OR]) { 779 nla_memcpy(&mb, tb[CGW_FDMOD_OR], CGW_FDMODATTR_LEN); 780 781 canfdframecpy(&mod->modframe.or, &mb.cf); 782 mod->modtype.or = mb.modtype; 783 784 if (mb.modtype & CGW_MOD_ID) 785 mod->modfunc[modidx++] = mod_or_id; 786 787 if (mb.modtype & CGW_MOD_LEN) 788 mod->modfunc[modidx++] = mod_or_len; 789 790 if (mb.modtype & CGW_MOD_FLAGS) 791 mod->modfunc[modidx++] = mod_or_flags; 792 793 if (mb.modtype & CGW_MOD_DATA) 794 mod->modfunc[modidx++] = mod_or_fddata; 795 } 796 797 if (tb[CGW_FDMOD_XOR]) { 798 nla_memcpy(&mb, tb[CGW_FDMOD_XOR], CGW_FDMODATTR_LEN); 799 800 canfdframecpy(&mod->modframe.xor, &mb.cf); 801 mod->modtype.xor = mb.modtype; 802 803 if (mb.modtype & CGW_MOD_ID) 804 mod->modfunc[modidx++] = mod_xor_id; 805 806 if (mb.modtype & CGW_MOD_LEN) 807 mod->modfunc[modidx++] = mod_xor_len; 808 809 if (mb.modtype & CGW_MOD_FLAGS) 810 mod->modfunc[modidx++] = mod_xor_flags; 811 812 if (mb.modtype & CGW_MOD_DATA) 813 mod->modfunc[modidx++] = mod_xor_fddata; 814 } 815 816 if (tb[CGW_FDMOD_SET]) { 817 nla_memcpy(&mb, tb[CGW_FDMOD_SET], CGW_FDMODATTR_LEN); 818 819 canfdframecpy(&mod->modframe.set, &mb.cf); 820 mod->modtype.set = mb.modtype; 821 822 if (mb.modtype & CGW_MOD_ID) 823 mod->modfunc[modidx++] = mod_set_id; 824 825 if (mb.modtype & CGW_MOD_LEN) 826 mod->modfunc[modidx++] = mod_set_len; 827 828 if (mb.modtype & CGW_MOD_FLAGS) 829 mod->modfunc[modidx++] = mod_set_flags; 830 831 if (mb.modtype & CGW_MOD_DATA) 832 mod->modfunc[modidx++] = mod_set_fddata; 833 } 834 } else { 835 struct cgw_frame_mod mb; 836 837 if (tb[CGW_MOD_AND]) { 838 nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN); 839 840 canframecpy(&mod->modframe.and, &mb.cf); 841 mod->modtype.and = mb.modtype; 842 843 if (mb.modtype & CGW_MOD_ID) 844 mod->modfunc[modidx++] = mod_and_id; 845 846 if (mb.modtype & CGW_MOD_LEN) 847 mod->modfunc[modidx++] = mod_and_len; 848 849 if (mb.modtype & CGW_MOD_DATA) 850 mod->modfunc[modidx++] = mod_and_data; 851 } 852 853 if (tb[CGW_MOD_OR]) { 854 nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN); 855 856 canframecpy(&mod->modframe.or, &mb.cf); 857 mod->modtype.or = mb.modtype; 858 859 if (mb.modtype & CGW_MOD_ID) 860 mod->modfunc[modidx++] = mod_or_id; 861 862 if (mb.modtype & CGW_MOD_LEN) 863 mod->modfunc[modidx++] = mod_or_len; 864 865 if (mb.modtype & CGW_MOD_DATA) 866 mod->modfunc[modidx++] = mod_or_data; 867 } 868 869 if (tb[CGW_MOD_XOR]) { 870 nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN); 871 872 canframecpy(&mod->modframe.xor, &mb.cf); 873 mod->modtype.xor = mb.modtype; 874 875 if (mb.modtype & CGW_MOD_ID) 876 mod->modfunc[modidx++] = mod_xor_id; 877 878 if (mb.modtype & CGW_MOD_LEN) 879 mod->modfunc[modidx++] = mod_xor_len; 880 881 if (mb.modtype & CGW_MOD_DATA) 882 mod->modfunc[modidx++] = mod_xor_data; 883 } 884 885 if (tb[CGW_MOD_SET]) { 886 nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN); 887 888 canframecpy(&mod->modframe.set, &mb.cf); 889 mod->modtype.set = mb.modtype; 890 891 if (mb.modtype & CGW_MOD_ID) 892 mod->modfunc[modidx++] = mod_set_id; 893 894 if (mb.modtype & CGW_MOD_LEN) 895 mod->modfunc[modidx++] = mod_set_len; 896 897 if (mb.modtype & CGW_MOD_DATA) 898 mod->modfunc[modidx++] = mod_set_data; 899 } 900 } 901 902 /* check for checksum operations after CAN frame modifications */ 903 if (modidx) { 904 if (tb[CGW_CS_CRC8]) { 905 struct cgw_csum_crc8 *c = nla_data(tb[CGW_CS_CRC8]); 906 907 err = cgw_chk_csum_parms(c->from_idx, c->to_idx, 908 c->result_idx, r); 909 if (err) 910 return err; 911 912 nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8], 913 CGW_CS_CRC8_LEN); 914 915 /* select dedicated processing function to reduce 916 * runtime operations in receive hot path. 917 */ 918 if (c->from_idx < 0 || c->to_idx < 0 || 919 c->result_idx < 0) 920 mod->csumfunc.crc8 = cgw_csum_crc8_rel; 921 else if (c->from_idx <= c->to_idx) 922 mod->csumfunc.crc8 = cgw_csum_crc8_pos; 923 else 924 mod->csumfunc.crc8 = cgw_csum_crc8_neg; 925 } 926 927 if (tb[CGW_CS_XOR]) { 928 struct cgw_csum_xor *c = nla_data(tb[CGW_CS_XOR]); 929 930 err = cgw_chk_csum_parms(c->from_idx, c->to_idx, 931 c->result_idx, r); 932 if (err) 933 return err; 934 935 nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR], 936 CGW_CS_XOR_LEN); 937 938 /* select dedicated processing function to reduce 939 * runtime operations in receive hot path. 940 */ 941 if (c->from_idx < 0 || c->to_idx < 0 || 942 c->result_idx < 0) 943 mod->csumfunc.xor = cgw_csum_xor_rel; 944 else if (c->from_idx <= c->to_idx) 945 mod->csumfunc.xor = cgw_csum_xor_pos; 946 else 947 mod->csumfunc.xor = cgw_csum_xor_neg; 948 } 949 950 if (tb[CGW_MOD_UID]) 951 nla_memcpy(&mod->uid, tb[CGW_MOD_UID], sizeof(u32)); 952 } 953 954 if (gwtype == CGW_TYPE_CAN_CAN) { 955 /* check CGW_TYPE_CAN_CAN specific attributes */ 956 struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr; 957 958 memset(ccgw, 0, sizeof(*ccgw)); 959 960 /* check for can_filter in attributes */ 961 if (tb[CGW_FILTER]) 962 nla_memcpy(&ccgw->filter, tb[CGW_FILTER], 963 sizeof(struct can_filter)); 964 965 err = -ENODEV; 966 967 /* specifying two interfaces is mandatory */ 968 if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF]) 969 return err; 970 971 ccgw->src_idx = nla_get_u32(tb[CGW_SRC_IF]); 972 ccgw->dst_idx = nla_get_u32(tb[CGW_DST_IF]); 973 974 /* both indices set to 0 for flushing all routing entries */ 975 if (!ccgw->src_idx && !ccgw->dst_idx) 976 return 0; 977 978 /* only one index set to 0 is an error */ 979 if (!ccgw->src_idx || !ccgw->dst_idx) 980 return err; 981 } 982 983 /* add the checks for other gwtypes here */ 984 985 return 0; 986 } 987 988 static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh, 989 struct netlink_ext_ack *extack) 990 { 991 struct net *net = sock_net(skb->sk); 992 struct rtcanmsg *r; 993 struct cgw_job *gwj; 994 struct cf_mod mod; 995 struct can_can_gw ccgw; 996 u8 limhops = 0; 997 int err = 0; 998 999 if (!netlink_capable(skb, CAP_NET_ADMIN)) 1000 return -EPERM; 1001 1002 if (nlmsg_len(nlh) < sizeof(*r)) 1003 return -EINVAL; 1004 1005 r = nlmsg_data(nlh); 1006 if (r->can_family != AF_CAN) 1007 return -EPFNOSUPPORT; 1008 1009 /* so far we only support CAN -> CAN routings */ 1010 if (r->gwtype != CGW_TYPE_CAN_CAN) 1011 return -EINVAL; 1012 1013 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops); 1014 if (err < 0) 1015 return err; 1016 1017 if (mod.uid) { 1018 ASSERT_RTNL(); 1019 1020 /* check for updating an existing job with identical uid */ 1021 hlist_for_each_entry(gwj, &net->can.cgw_list, list) { 1022 if (gwj->mod.uid != mod.uid) 1023 continue; 1024 1025 /* interfaces & filters must be identical */ 1026 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw))) 1027 return -EINVAL; 1028 1029 /* update modifications with disabled softirq & quit */ 1030 local_bh_disable(); 1031 memcpy(&gwj->mod, &mod, sizeof(mod)); 1032 local_bh_enable(); 1033 return 0; 1034 } 1035 } 1036 1037 /* ifindex == 0 is not allowed for job creation */ 1038 if (!ccgw.src_idx || !ccgw.dst_idx) 1039 return -ENODEV; 1040 1041 gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL); 1042 if (!gwj) 1043 return -ENOMEM; 1044 1045 gwj->handled_frames = 0; 1046 gwj->dropped_frames = 0; 1047 gwj->deleted_frames = 0; 1048 gwj->flags = r->flags; 1049 gwj->gwtype = r->gwtype; 1050 gwj->limit_hops = limhops; 1051 1052 /* insert already parsed information */ 1053 memcpy(&gwj->mod, &mod, sizeof(mod)); 1054 memcpy(&gwj->ccgw, &ccgw, sizeof(ccgw)); 1055 1056 err = -ENODEV; 1057 1058 gwj->src.dev = __dev_get_by_index(net, gwj->ccgw.src_idx); 1059 1060 if (!gwj->src.dev) 1061 goto out; 1062 1063 if (gwj->src.dev->type != ARPHRD_CAN) 1064 goto out; 1065 1066 gwj->dst.dev = __dev_get_by_index(net, gwj->ccgw.dst_idx); 1067 1068 if (!gwj->dst.dev) 1069 goto out; 1070 1071 if (gwj->dst.dev->type != ARPHRD_CAN) 1072 goto out; 1073 1074 ASSERT_RTNL(); 1075 1076 err = cgw_register_filter(net, gwj); 1077 if (!err) 1078 hlist_add_head_rcu(&gwj->list, &net->can.cgw_list); 1079 out: 1080 if (err) 1081 kmem_cache_free(cgw_cache, gwj); 1082 1083 return err; 1084 } 1085 1086 static void cgw_remove_all_jobs(struct net *net) 1087 { 1088 struct cgw_job *gwj = NULL; 1089 struct hlist_node *nx; 1090 1091 ASSERT_RTNL(); 1092 1093 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) { 1094 hlist_del(&gwj->list); 1095 cgw_unregister_filter(net, gwj); 1096 kmem_cache_free(cgw_cache, gwj); 1097 } 1098 } 1099 1100 static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh, 1101 struct netlink_ext_ack *extack) 1102 { 1103 struct net *net = sock_net(skb->sk); 1104 struct cgw_job *gwj = NULL; 1105 struct hlist_node *nx; 1106 struct rtcanmsg *r; 1107 struct cf_mod mod; 1108 struct can_can_gw ccgw; 1109 u8 limhops = 0; 1110 int err = 0; 1111 1112 if (!netlink_capable(skb, CAP_NET_ADMIN)) 1113 return -EPERM; 1114 1115 if (nlmsg_len(nlh) < sizeof(*r)) 1116 return -EINVAL; 1117 1118 r = nlmsg_data(nlh); 1119 if (r->can_family != AF_CAN) 1120 return -EPFNOSUPPORT; 1121 1122 /* so far we only support CAN -> CAN routings */ 1123 if (r->gwtype != CGW_TYPE_CAN_CAN) 1124 return -EINVAL; 1125 1126 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops); 1127 if (err < 0) 1128 return err; 1129 1130 /* two interface indices both set to 0 => remove all entries */ 1131 if (!ccgw.src_idx && !ccgw.dst_idx) { 1132 cgw_remove_all_jobs(net); 1133 return 0; 1134 } 1135 1136 err = -EINVAL; 1137 1138 ASSERT_RTNL(); 1139 1140 /* remove only the first matching entry */ 1141 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) { 1142 if (gwj->flags != r->flags) 1143 continue; 1144 1145 if (gwj->limit_hops != limhops) 1146 continue; 1147 1148 /* we have a match when uid is enabled and identical */ 1149 if (gwj->mod.uid || mod.uid) { 1150 if (gwj->mod.uid != mod.uid) 1151 continue; 1152 } else { 1153 /* no uid => check for identical modifications */ 1154 if (memcmp(&gwj->mod, &mod, sizeof(mod))) 1155 continue; 1156 } 1157 1158 /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */ 1159 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw))) 1160 continue; 1161 1162 hlist_del(&gwj->list); 1163 cgw_unregister_filter(net, gwj); 1164 kmem_cache_free(cgw_cache, gwj); 1165 err = 0; 1166 break; 1167 } 1168 1169 return err; 1170 } 1171 1172 static int __net_init cangw_pernet_init(struct net *net) 1173 { 1174 INIT_HLIST_HEAD(&net->can.cgw_list); 1175 return 0; 1176 } 1177 1178 static void __net_exit cangw_pernet_exit(struct net *net) 1179 { 1180 rtnl_lock(); 1181 cgw_remove_all_jobs(net); 1182 rtnl_unlock(); 1183 } 1184 1185 static struct pernet_operations cangw_pernet_ops = { 1186 .init = cangw_pernet_init, 1187 .exit = cangw_pernet_exit, 1188 }; 1189 1190 static __init int cgw_module_init(void) 1191 { 1192 int ret; 1193 1194 /* sanitize given module parameter */ 1195 max_hops = clamp_t(unsigned int, max_hops, CGW_MIN_HOPS, CGW_MAX_HOPS); 1196 1197 pr_info("can: netlink gateway (rev " CAN_GW_VERSION ") max_hops=%d\n", 1198 max_hops); 1199 1200 ret = register_pernet_subsys(&cangw_pernet_ops); 1201 if (ret) 1202 return ret; 1203 1204 ret = -ENOMEM; 1205 cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job), 1206 0, 0, NULL); 1207 if (!cgw_cache) 1208 goto out_cache_create; 1209 1210 /* set notifier */ 1211 notifier.notifier_call = cgw_notifier; 1212 ret = register_netdevice_notifier(¬ifier); 1213 if (ret) 1214 goto out_register_notifier; 1215 1216 ret = rtnl_register_module(THIS_MODULE, PF_CAN, RTM_GETROUTE, 1217 NULL, cgw_dump_jobs, 0); 1218 if (ret) 1219 goto out_rtnl_register1; 1220 1221 ret = rtnl_register_module(THIS_MODULE, PF_CAN, RTM_NEWROUTE, 1222 cgw_create_job, NULL, 0); 1223 if (ret) 1224 goto out_rtnl_register2; 1225 ret = rtnl_register_module(THIS_MODULE, PF_CAN, RTM_DELROUTE, 1226 cgw_remove_job, NULL, 0); 1227 if (ret) 1228 goto out_rtnl_register3; 1229 1230 return 0; 1231 1232 out_rtnl_register3: 1233 rtnl_unregister(PF_CAN, RTM_NEWROUTE); 1234 out_rtnl_register2: 1235 rtnl_unregister(PF_CAN, RTM_GETROUTE); 1236 out_rtnl_register1: 1237 unregister_netdevice_notifier(¬ifier); 1238 out_register_notifier: 1239 kmem_cache_destroy(cgw_cache); 1240 out_cache_create: 1241 unregister_pernet_subsys(&cangw_pernet_ops); 1242 1243 return ret; 1244 } 1245 1246 static __exit void cgw_module_exit(void) 1247 { 1248 rtnl_unregister_all(PF_CAN); 1249 1250 unregister_netdevice_notifier(¬ifier); 1251 1252 unregister_pernet_subsys(&cangw_pernet_ops); 1253 rcu_barrier(); /* Wait for completion of call_rcu()'s */ 1254 1255 kmem_cache_destroy(cgw_cache); 1256 } 1257 1258 module_init(cgw_module_init); 1259 module_exit(cgw_module_exit); 1260