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