1 /* 2 * gw.c - CAN frame Gateway/Router/Bridge with netlink interface 3 * 4 * Copyright (c) 2011 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 "20130117" 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, S_IRUGO); 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 HLIST_HEAD(cgw_list); 83 static struct notifier_block notifier; 84 85 static struct kmem_cache *cgw_cache __read_mostly; 86 87 /* structure that contains the (on-the-fly) CAN frame modifications */ 88 struct cf_mod { 89 struct { 90 struct can_frame and; 91 struct can_frame or; 92 struct can_frame xor; 93 struct can_frame set; 94 } modframe; 95 struct { 96 u8 and; 97 u8 or; 98 u8 xor; 99 u8 set; 100 } modtype; 101 void (*modfunc[MAX_MODFUNCTIONS])(struct can_frame *cf, 102 struct cf_mod *mod); 103 104 /* CAN frame checksum calculation after CAN frame modifications */ 105 struct { 106 struct cgw_csum_xor xor; 107 struct cgw_csum_crc8 crc8; 108 } csum; 109 struct { 110 void (*xor)(struct can_frame *cf, struct cgw_csum_xor *xor); 111 void (*crc8)(struct can_frame *cf, struct cgw_csum_crc8 *crc8); 112 } csumfunc; 113 u32 uid; 114 }; 115 116 117 /* 118 * So far we just support CAN -> CAN routing and frame modifications. 119 * 120 * The internal can_can_gw structure contains data and attributes for 121 * a CAN -> CAN gateway job. 122 */ 123 struct can_can_gw { 124 struct can_filter filter; 125 int src_idx; 126 int dst_idx; 127 }; 128 129 /* list entry for CAN gateways jobs */ 130 struct cgw_job { 131 struct hlist_node list; 132 struct rcu_head rcu; 133 u32 handled_frames; 134 u32 dropped_frames; 135 u32 deleted_frames; 136 struct cf_mod mod; 137 union { 138 /* CAN frame data source */ 139 struct net_device *dev; 140 } src; 141 union { 142 /* CAN frame data destination */ 143 struct net_device *dev; 144 } dst; 145 union { 146 struct can_can_gw ccgw; 147 /* tbc */ 148 }; 149 u8 gwtype; 150 u8 limit_hops; 151 u16 flags; 152 }; 153 154 /* modification functions that are invoked in the hot path in can_can_gw_rcv */ 155 156 #define MODFUNC(func, op) static void func(struct can_frame *cf, \ 157 struct cf_mod *mod) { op ; } 158 159 MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id) 160 MODFUNC(mod_and_dlc, cf->can_dlc &= mod->modframe.and.can_dlc) 161 MODFUNC(mod_and_data, *(u64 *)cf->data &= *(u64 *)mod->modframe.and.data) 162 MODFUNC(mod_or_id, cf->can_id |= mod->modframe.or.can_id) 163 MODFUNC(mod_or_dlc, cf->can_dlc |= mod->modframe.or.can_dlc) 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_dlc, cf->can_dlc ^= mod->modframe.xor.can_dlc) 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_dlc, cf->can_dlc = mod->modframe.set.can_dlc) 170 MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data) 171 172 static inline void canframecpy(struct can_frame *dst, struct can_frame *src) 173 { 174 /* 175 * Copy the struct members separately to ensure that no uninitialized 176 * data are copied in the 3 bytes hole of the struct. This is needed 177 * to make easy compares of the data in the struct cf_mod. 178 */ 179 180 dst->can_id = src->can_id; 181 dst->can_dlc = src->can_dlc; 182 *(u64 *)dst->data = *(u64 *)src->data; 183 } 184 185 static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re) 186 { 187 /* 188 * absolute dlc values 0 .. 7 => 0 .. 7, e.g. data [0] 189 * relative to received dlc -1 .. -8 : 190 * e.g. for received dlc = 8 191 * -1 => index = 7 (data[7]) 192 * -3 => index = 5 (data[5]) 193 * -8 => index = 0 (data[0]) 194 */ 195 196 if (fr > -9 && fr < 8 && 197 to > -9 && to < 8 && 198 re > -9 && re < 8) 199 return 0; 200 else 201 return -EINVAL; 202 } 203 204 static inline int calc_idx(int idx, int rx_dlc) 205 { 206 if (idx < 0) 207 return rx_dlc + idx; 208 else 209 return idx; 210 } 211 212 static void cgw_csum_xor_rel(struct can_frame *cf, struct cgw_csum_xor *xor) 213 { 214 int from = calc_idx(xor->from_idx, cf->can_dlc); 215 int to = calc_idx(xor->to_idx, cf->can_dlc); 216 int res = calc_idx(xor->result_idx, cf->can_dlc); 217 u8 val = xor->init_xor_val; 218 int i; 219 220 if (from < 0 || to < 0 || res < 0) 221 return; 222 223 if (from <= to) { 224 for (i = from; i <= to; i++) 225 val ^= cf->data[i]; 226 } else { 227 for (i = from; i >= to; i--) 228 val ^= cf->data[i]; 229 } 230 231 cf->data[res] = val; 232 } 233 234 static void cgw_csum_xor_pos(struct can_frame *cf, struct cgw_csum_xor *xor) 235 { 236 u8 val = xor->init_xor_val; 237 int i; 238 239 for (i = xor->from_idx; i <= xor->to_idx; i++) 240 val ^= cf->data[i]; 241 242 cf->data[xor->result_idx] = val; 243 } 244 245 static void cgw_csum_xor_neg(struct can_frame *cf, struct cgw_csum_xor *xor) 246 { 247 u8 val = xor->init_xor_val; 248 int i; 249 250 for (i = xor->from_idx; i >= xor->to_idx; i--) 251 val ^= cf->data[i]; 252 253 cf->data[xor->result_idx] = val; 254 } 255 256 static void cgw_csum_crc8_rel(struct can_frame *cf, struct cgw_csum_crc8 *crc8) 257 { 258 int from = calc_idx(crc8->from_idx, cf->can_dlc); 259 int to = calc_idx(crc8->to_idx, cf->can_dlc); 260 int res = calc_idx(crc8->result_idx, cf->can_dlc); 261 u8 crc = crc8->init_crc_val; 262 int i; 263 264 if (from < 0 || to < 0 || res < 0) 265 return; 266 267 if (from <= to) { 268 for (i = crc8->from_idx; i <= crc8->to_idx; i++) 269 crc = crc8->crctab[crc^cf->data[i]]; 270 } else { 271 for (i = crc8->from_idx; i >= crc8->to_idx; i--) 272 crc = crc8->crctab[crc^cf->data[i]]; 273 } 274 275 switch (crc8->profile) { 276 277 case CGW_CRC8PRF_1U8: 278 crc = crc8->crctab[crc^crc8->profile_data[0]]; 279 break; 280 281 case CGW_CRC8PRF_16U8: 282 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]]; 283 break; 284 285 case CGW_CRC8PRF_SFFID_XOR: 286 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^ 287 (cf->can_id >> 8 & 0xFF)]; 288 break; 289 290 } 291 292 cf->data[crc8->result_idx] = crc^crc8->final_xor_val; 293 } 294 295 static void cgw_csum_crc8_pos(struct can_frame *cf, struct cgw_csum_crc8 *crc8) 296 { 297 u8 crc = crc8->init_crc_val; 298 int i; 299 300 for (i = crc8->from_idx; i <= crc8->to_idx; i++) 301 crc = crc8->crctab[crc^cf->data[i]]; 302 303 switch (crc8->profile) { 304 305 case CGW_CRC8PRF_1U8: 306 crc = crc8->crctab[crc^crc8->profile_data[0]]; 307 break; 308 309 case CGW_CRC8PRF_16U8: 310 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]]; 311 break; 312 313 case CGW_CRC8PRF_SFFID_XOR: 314 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^ 315 (cf->can_id >> 8 & 0xFF)]; 316 break; 317 } 318 319 cf->data[crc8->result_idx] = crc^crc8->final_xor_val; 320 } 321 322 static void cgw_csum_crc8_neg(struct can_frame *cf, struct cgw_csum_crc8 *crc8) 323 { 324 u8 crc = crc8->init_crc_val; 325 int i; 326 327 for (i = crc8->from_idx; i >= crc8->to_idx; i--) 328 crc = crc8->crctab[crc^cf->data[i]]; 329 330 switch (crc8->profile) { 331 332 case CGW_CRC8PRF_1U8: 333 crc = crc8->crctab[crc^crc8->profile_data[0]]; 334 break; 335 336 case CGW_CRC8PRF_16U8: 337 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]]; 338 break; 339 340 case CGW_CRC8PRF_SFFID_XOR: 341 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^ 342 (cf->can_id >> 8 & 0xFF)]; 343 break; 344 } 345 346 cf->data[crc8->result_idx] = crc^crc8->final_xor_val; 347 } 348 349 /* the receive & process & send function */ 350 static void can_can_gw_rcv(struct sk_buff *skb, void *data) 351 { 352 struct cgw_job *gwj = (struct cgw_job *)data; 353 struct can_frame *cf; 354 struct sk_buff *nskb; 355 int modidx = 0; 356 357 /* 358 * Do not handle CAN frames routed more than 'max_hops' times. 359 * In general we should never catch this delimiter which is intended 360 * to cover a misconfiguration protection (e.g. circular CAN routes). 361 * 362 * The Controller Area Network controllers only accept CAN frames with 363 * correct CRCs - which are not visible in the controller registers. 364 * According to skbuff.h documentation the csum_start element for IP 365 * checksums is undefined/unused when ip_summed == CHECKSUM_UNNECESSARY. 366 * Only CAN skbs can be processed here which already have this property. 367 */ 368 369 #define cgw_hops(skb) ((skb)->csum_start) 370 371 BUG_ON(skb->ip_summed != CHECKSUM_UNNECESSARY); 372 373 if (cgw_hops(skb) >= max_hops) { 374 /* indicate deleted frames due to misconfiguration */ 375 gwj->deleted_frames++; 376 return; 377 } 378 379 if (!(gwj->dst.dev->flags & IFF_UP)) { 380 gwj->dropped_frames++; 381 return; 382 } 383 384 /* is sending the skb back to the incoming interface not allowed? */ 385 if (!(gwj->flags & CGW_FLAGS_CAN_IIF_TX_OK) && 386 can_skb_prv(skb)->ifindex == gwj->dst.dev->ifindex) 387 return; 388 389 /* 390 * clone the given skb, which has not been done in can_rcv() 391 * 392 * When there is at least one modification function activated, 393 * we need to copy the skb as we want to modify skb->data. 394 */ 395 if (gwj->mod.modfunc[0]) 396 nskb = skb_copy(skb, GFP_ATOMIC); 397 else 398 nskb = skb_clone(skb, GFP_ATOMIC); 399 400 if (!nskb) { 401 gwj->dropped_frames++; 402 return; 403 } 404 405 /* put the incremented hop counter in the cloned skb */ 406 cgw_hops(nskb) = cgw_hops(skb) + 1; 407 408 /* first processing of this CAN frame -> adjust to private hop limit */ 409 if (gwj->limit_hops && cgw_hops(nskb) == 1) 410 cgw_hops(nskb) = max_hops - gwj->limit_hops + 1; 411 412 nskb->dev = gwj->dst.dev; 413 414 /* pointer to modifiable CAN frame */ 415 cf = (struct can_frame *)nskb->data; 416 417 /* perform preprocessed modification functions if there are any */ 418 while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx]) 419 (*gwj->mod.modfunc[modidx++])(cf, &gwj->mod); 420 421 /* check for checksum updates when the CAN frame has been modified */ 422 if (modidx) { 423 if (gwj->mod.csumfunc.crc8) 424 (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8); 425 426 if (gwj->mod.csumfunc.xor) 427 (*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor); 428 } 429 430 /* clear the skb timestamp if not configured the other way */ 431 if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP)) 432 nskb->tstamp = 0; 433 434 /* send to netdevice */ 435 if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO)) 436 gwj->dropped_frames++; 437 else 438 gwj->handled_frames++; 439 } 440 441 static inline int cgw_register_filter(struct cgw_job *gwj) 442 { 443 return can_rx_register(gwj->src.dev, gwj->ccgw.filter.can_id, 444 gwj->ccgw.filter.can_mask, can_can_gw_rcv, 445 gwj, "gw", NULL); 446 } 447 448 static inline void cgw_unregister_filter(struct cgw_job *gwj) 449 { 450 can_rx_unregister(gwj->src.dev, gwj->ccgw.filter.can_id, 451 gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj); 452 } 453 454 static int cgw_notifier(struct notifier_block *nb, 455 unsigned long msg, void *ptr) 456 { 457 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 458 459 if (!net_eq(dev_net(dev), &init_net)) 460 return NOTIFY_DONE; 461 if (dev->type != ARPHRD_CAN) 462 return NOTIFY_DONE; 463 464 if (msg == NETDEV_UNREGISTER) { 465 466 struct cgw_job *gwj = NULL; 467 struct hlist_node *nx; 468 469 ASSERT_RTNL(); 470 471 hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) { 472 473 if (gwj->src.dev == dev || gwj->dst.dev == dev) { 474 hlist_del(&gwj->list); 475 cgw_unregister_filter(gwj); 476 kmem_cache_free(cgw_cache, gwj); 477 } 478 } 479 } 480 481 return NOTIFY_DONE; 482 } 483 484 static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type, 485 u32 pid, u32 seq, int flags) 486 { 487 struct cgw_frame_mod mb; 488 struct rtcanmsg *rtcan; 489 struct nlmsghdr *nlh; 490 491 nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags); 492 if (!nlh) 493 return -EMSGSIZE; 494 495 rtcan = nlmsg_data(nlh); 496 rtcan->can_family = AF_CAN; 497 rtcan->gwtype = gwj->gwtype; 498 rtcan->flags = gwj->flags; 499 500 /* add statistics if available */ 501 502 if (gwj->handled_frames) { 503 if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0) 504 goto cancel; 505 } 506 507 if (gwj->dropped_frames) { 508 if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0) 509 goto cancel; 510 } 511 512 if (gwj->deleted_frames) { 513 if (nla_put_u32(skb, CGW_DELETED, gwj->deleted_frames) < 0) 514 goto cancel; 515 } 516 517 /* check non default settings of attributes */ 518 519 if (gwj->limit_hops) { 520 if (nla_put_u8(skb, CGW_LIM_HOPS, gwj->limit_hops) < 0) 521 goto cancel; 522 } 523 524 if (gwj->mod.modtype.and) { 525 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf)); 526 mb.modtype = gwj->mod.modtype.and; 527 if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0) 528 goto cancel; 529 } 530 531 if (gwj->mod.modtype.or) { 532 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf)); 533 mb.modtype = gwj->mod.modtype.or; 534 if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0) 535 goto cancel; 536 } 537 538 if (gwj->mod.modtype.xor) { 539 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf)); 540 mb.modtype = gwj->mod.modtype.xor; 541 if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0) 542 goto cancel; 543 } 544 545 if (gwj->mod.modtype.set) { 546 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf)); 547 mb.modtype = gwj->mod.modtype.set; 548 if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0) 549 goto cancel; 550 } 551 552 if (gwj->mod.uid) { 553 if (nla_put_u32(skb, CGW_MOD_UID, gwj->mod.uid) < 0) 554 goto cancel; 555 } 556 557 if (gwj->mod.csumfunc.crc8) { 558 if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN, 559 &gwj->mod.csum.crc8) < 0) 560 goto cancel; 561 } 562 563 if (gwj->mod.csumfunc.xor) { 564 if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN, 565 &gwj->mod.csum.xor) < 0) 566 goto cancel; 567 } 568 569 if (gwj->gwtype == CGW_TYPE_CAN_CAN) { 570 571 if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) { 572 if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter), 573 &gwj->ccgw.filter) < 0) 574 goto cancel; 575 } 576 577 if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0) 578 goto cancel; 579 580 if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0) 581 goto cancel; 582 } 583 584 nlmsg_end(skb, nlh); 585 return 0; 586 587 cancel: 588 nlmsg_cancel(skb, nlh); 589 return -EMSGSIZE; 590 } 591 592 /* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */ 593 static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb) 594 { 595 struct cgw_job *gwj = NULL; 596 int idx = 0; 597 int s_idx = cb->args[0]; 598 599 rcu_read_lock(); 600 hlist_for_each_entry_rcu(gwj, &cgw_list, list) { 601 if (idx < s_idx) 602 goto cont; 603 604 if (cgw_put_job(skb, gwj, RTM_NEWROUTE, NETLINK_CB(cb->skb).portid, 605 cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0) 606 break; 607 cont: 608 idx++; 609 } 610 rcu_read_unlock(); 611 612 cb->args[0] = idx; 613 614 return skb->len; 615 } 616 617 static const struct nla_policy cgw_policy[CGW_MAX+1] = { 618 [CGW_MOD_AND] = { .len = sizeof(struct cgw_frame_mod) }, 619 [CGW_MOD_OR] = { .len = sizeof(struct cgw_frame_mod) }, 620 [CGW_MOD_XOR] = { .len = sizeof(struct cgw_frame_mod) }, 621 [CGW_MOD_SET] = { .len = sizeof(struct cgw_frame_mod) }, 622 [CGW_CS_XOR] = { .len = sizeof(struct cgw_csum_xor) }, 623 [CGW_CS_CRC8] = { .len = sizeof(struct cgw_csum_crc8) }, 624 [CGW_SRC_IF] = { .type = NLA_U32 }, 625 [CGW_DST_IF] = { .type = NLA_U32 }, 626 [CGW_FILTER] = { .len = sizeof(struct can_filter) }, 627 [CGW_LIM_HOPS] = { .type = NLA_U8 }, 628 [CGW_MOD_UID] = { .type = NLA_U32 }, 629 }; 630 631 /* check for common and gwtype specific attributes */ 632 static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod, 633 u8 gwtype, void *gwtypeattr, u8 *limhops) 634 { 635 struct nlattr *tb[CGW_MAX+1]; 636 struct cgw_frame_mod mb; 637 int modidx = 0; 638 int err = 0; 639 640 /* initialize modification & checksum data space */ 641 memset(mod, 0, sizeof(*mod)); 642 643 err = nlmsg_parse(nlh, sizeof(struct rtcanmsg), tb, CGW_MAX, 644 cgw_policy); 645 if (err < 0) 646 return err; 647 648 if (tb[CGW_LIM_HOPS]) { 649 *limhops = nla_get_u8(tb[CGW_LIM_HOPS]); 650 651 if (*limhops < 1 || *limhops > max_hops) 652 return -EINVAL; 653 } 654 655 /* check for AND/OR/XOR/SET modifications */ 656 657 if (tb[CGW_MOD_AND]) { 658 nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN); 659 660 canframecpy(&mod->modframe.and, &mb.cf); 661 mod->modtype.and = mb.modtype; 662 663 if (mb.modtype & CGW_MOD_ID) 664 mod->modfunc[modidx++] = mod_and_id; 665 666 if (mb.modtype & CGW_MOD_DLC) 667 mod->modfunc[modidx++] = mod_and_dlc; 668 669 if (mb.modtype & CGW_MOD_DATA) 670 mod->modfunc[modidx++] = mod_and_data; 671 } 672 673 if (tb[CGW_MOD_OR]) { 674 nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN); 675 676 canframecpy(&mod->modframe.or, &mb.cf); 677 mod->modtype.or = mb.modtype; 678 679 if (mb.modtype & CGW_MOD_ID) 680 mod->modfunc[modidx++] = mod_or_id; 681 682 if (mb.modtype & CGW_MOD_DLC) 683 mod->modfunc[modidx++] = mod_or_dlc; 684 685 if (mb.modtype & CGW_MOD_DATA) 686 mod->modfunc[modidx++] = mod_or_data; 687 } 688 689 if (tb[CGW_MOD_XOR]) { 690 nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN); 691 692 canframecpy(&mod->modframe.xor, &mb.cf); 693 mod->modtype.xor = mb.modtype; 694 695 if (mb.modtype & CGW_MOD_ID) 696 mod->modfunc[modidx++] = mod_xor_id; 697 698 if (mb.modtype & CGW_MOD_DLC) 699 mod->modfunc[modidx++] = mod_xor_dlc; 700 701 if (mb.modtype & CGW_MOD_DATA) 702 mod->modfunc[modidx++] = mod_xor_data; 703 } 704 705 if (tb[CGW_MOD_SET]) { 706 nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN); 707 708 canframecpy(&mod->modframe.set, &mb.cf); 709 mod->modtype.set = mb.modtype; 710 711 if (mb.modtype & CGW_MOD_ID) 712 mod->modfunc[modidx++] = mod_set_id; 713 714 if (mb.modtype & CGW_MOD_DLC) 715 mod->modfunc[modidx++] = mod_set_dlc; 716 717 if (mb.modtype & CGW_MOD_DATA) 718 mod->modfunc[modidx++] = mod_set_data; 719 } 720 721 /* check for checksum operations after CAN frame modifications */ 722 if (modidx) { 723 724 if (tb[CGW_CS_CRC8]) { 725 struct cgw_csum_crc8 *c = nla_data(tb[CGW_CS_CRC8]); 726 727 err = cgw_chk_csum_parms(c->from_idx, c->to_idx, 728 c->result_idx); 729 if (err) 730 return err; 731 732 nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8], 733 CGW_CS_CRC8_LEN); 734 735 /* 736 * select dedicated processing function to reduce 737 * runtime operations in receive hot path. 738 */ 739 if (c->from_idx < 0 || c->to_idx < 0 || 740 c->result_idx < 0) 741 mod->csumfunc.crc8 = cgw_csum_crc8_rel; 742 else if (c->from_idx <= c->to_idx) 743 mod->csumfunc.crc8 = cgw_csum_crc8_pos; 744 else 745 mod->csumfunc.crc8 = cgw_csum_crc8_neg; 746 } 747 748 if (tb[CGW_CS_XOR]) { 749 struct cgw_csum_xor *c = nla_data(tb[CGW_CS_XOR]); 750 751 err = cgw_chk_csum_parms(c->from_idx, c->to_idx, 752 c->result_idx); 753 if (err) 754 return err; 755 756 nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR], 757 CGW_CS_XOR_LEN); 758 759 /* 760 * select dedicated processing function to reduce 761 * runtime operations in receive hot path. 762 */ 763 if (c->from_idx < 0 || c->to_idx < 0 || 764 c->result_idx < 0) 765 mod->csumfunc.xor = cgw_csum_xor_rel; 766 else if (c->from_idx <= c->to_idx) 767 mod->csumfunc.xor = cgw_csum_xor_pos; 768 else 769 mod->csumfunc.xor = cgw_csum_xor_neg; 770 } 771 772 if (tb[CGW_MOD_UID]) { 773 nla_memcpy(&mod->uid, tb[CGW_MOD_UID], sizeof(u32)); 774 } 775 } 776 777 if (gwtype == CGW_TYPE_CAN_CAN) { 778 779 /* check CGW_TYPE_CAN_CAN specific attributes */ 780 781 struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr; 782 memset(ccgw, 0, sizeof(*ccgw)); 783 784 /* check for can_filter in attributes */ 785 if (tb[CGW_FILTER]) 786 nla_memcpy(&ccgw->filter, tb[CGW_FILTER], 787 sizeof(struct can_filter)); 788 789 err = -ENODEV; 790 791 /* specifying two interfaces is mandatory */ 792 if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF]) 793 return err; 794 795 ccgw->src_idx = nla_get_u32(tb[CGW_SRC_IF]); 796 ccgw->dst_idx = nla_get_u32(tb[CGW_DST_IF]); 797 798 /* both indices set to 0 for flushing all routing entries */ 799 if (!ccgw->src_idx && !ccgw->dst_idx) 800 return 0; 801 802 /* only one index set to 0 is an error */ 803 if (!ccgw->src_idx || !ccgw->dst_idx) 804 return err; 805 } 806 807 /* add the checks for other gwtypes here */ 808 809 return 0; 810 } 811 812 static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh) 813 { 814 struct rtcanmsg *r; 815 struct cgw_job *gwj; 816 struct cf_mod mod; 817 struct can_can_gw ccgw; 818 u8 limhops = 0; 819 int err = 0; 820 821 if (!netlink_capable(skb, CAP_NET_ADMIN)) 822 return -EPERM; 823 824 if (nlmsg_len(nlh) < sizeof(*r)) 825 return -EINVAL; 826 827 r = nlmsg_data(nlh); 828 if (r->can_family != AF_CAN) 829 return -EPFNOSUPPORT; 830 831 /* so far we only support CAN -> CAN routings */ 832 if (r->gwtype != CGW_TYPE_CAN_CAN) 833 return -EINVAL; 834 835 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops); 836 if (err < 0) 837 return err; 838 839 if (mod.uid) { 840 841 ASSERT_RTNL(); 842 843 /* check for updating an existing job with identical uid */ 844 hlist_for_each_entry(gwj, &cgw_list, list) { 845 846 if (gwj->mod.uid != mod.uid) 847 continue; 848 849 /* interfaces & filters must be identical */ 850 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw))) 851 return -EINVAL; 852 853 /* update modifications with disabled softirq & quit */ 854 local_bh_disable(); 855 memcpy(&gwj->mod, &mod, sizeof(mod)); 856 local_bh_enable(); 857 return 0; 858 } 859 } 860 861 /* ifindex == 0 is not allowed for job creation */ 862 if (!ccgw.src_idx || !ccgw.dst_idx) 863 return -ENODEV; 864 865 gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL); 866 if (!gwj) 867 return -ENOMEM; 868 869 gwj->handled_frames = 0; 870 gwj->dropped_frames = 0; 871 gwj->deleted_frames = 0; 872 gwj->flags = r->flags; 873 gwj->gwtype = r->gwtype; 874 gwj->limit_hops = limhops; 875 876 /* insert already parsed information */ 877 memcpy(&gwj->mod, &mod, sizeof(mod)); 878 memcpy(&gwj->ccgw, &ccgw, sizeof(ccgw)); 879 880 err = -ENODEV; 881 882 gwj->src.dev = __dev_get_by_index(&init_net, gwj->ccgw.src_idx); 883 884 if (!gwj->src.dev) 885 goto out; 886 887 if (gwj->src.dev->type != ARPHRD_CAN) 888 goto out; 889 890 gwj->dst.dev = __dev_get_by_index(&init_net, gwj->ccgw.dst_idx); 891 892 if (!gwj->dst.dev) 893 goto out; 894 895 if (gwj->dst.dev->type != ARPHRD_CAN) 896 goto out; 897 898 ASSERT_RTNL(); 899 900 err = cgw_register_filter(gwj); 901 if (!err) 902 hlist_add_head_rcu(&gwj->list, &cgw_list); 903 out: 904 if (err) 905 kmem_cache_free(cgw_cache, gwj); 906 907 return err; 908 } 909 910 static void cgw_remove_all_jobs(void) 911 { 912 struct cgw_job *gwj = NULL; 913 struct hlist_node *nx; 914 915 ASSERT_RTNL(); 916 917 hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) { 918 hlist_del(&gwj->list); 919 cgw_unregister_filter(gwj); 920 kmem_cache_free(cgw_cache, gwj); 921 } 922 } 923 924 static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh) 925 { 926 struct cgw_job *gwj = NULL; 927 struct hlist_node *nx; 928 struct rtcanmsg *r; 929 struct cf_mod mod; 930 struct can_can_gw ccgw; 931 u8 limhops = 0; 932 int err = 0; 933 934 if (!netlink_capable(skb, CAP_NET_ADMIN)) 935 return -EPERM; 936 937 if (nlmsg_len(nlh) < sizeof(*r)) 938 return -EINVAL; 939 940 r = nlmsg_data(nlh); 941 if (r->can_family != AF_CAN) 942 return -EPFNOSUPPORT; 943 944 /* so far we only support CAN -> CAN routings */ 945 if (r->gwtype != CGW_TYPE_CAN_CAN) 946 return -EINVAL; 947 948 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops); 949 if (err < 0) 950 return err; 951 952 /* two interface indices both set to 0 => remove all entries */ 953 if (!ccgw.src_idx && !ccgw.dst_idx) { 954 cgw_remove_all_jobs(); 955 return 0; 956 } 957 958 err = -EINVAL; 959 960 ASSERT_RTNL(); 961 962 /* remove only the first matching entry */ 963 hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) { 964 965 if (gwj->flags != r->flags) 966 continue; 967 968 if (gwj->limit_hops != limhops) 969 continue; 970 971 /* we have a match when uid is enabled and identical */ 972 if (gwj->mod.uid || mod.uid) { 973 if (gwj->mod.uid != mod.uid) 974 continue; 975 } else { 976 /* no uid => check for identical modifications */ 977 if (memcmp(&gwj->mod, &mod, sizeof(mod))) 978 continue; 979 } 980 981 /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */ 982 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw))) 983 continue; 984 985 hlist_del(&gwj->list); 986 cgw_unregister_filter(gwj); 987 kmem_cache_free(cgw_cache, gwj); 988 err = 0; 989 break; 990 } 991 992 return err; 993 } 994 995 static __init int cgw_module_init(void) 996 { 997 /* sanitize given module parameter */ 998 max_hops = clamp_t(unsigned int, max_hops, CGW_MIN_HOPS, CGW_MAX_HOPS); 999 1000 pr_info("can: netlink gateway (rev " CAN_GW_VERSION ") max_hops=%d\n", 1001 max_hops); 1002 1003 cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job), 1004 0, 0, NULL); 1005 1006 if (!cgw_cache) 1007 return -ENOMEM; 1008 1009 /* set notifier */ 1010 notifier.notifier_call = cgw_notifier; 1011 register_netdevice_notifier(¬ifier); 1012 1013 if (__rtnl_register(PF_CAN, RTM_GETROUTE, NULL, cgw_dump_jobs, NULL)) { 1014 unregister_netdevice_notifier(¬ifier); 1015 kmem_cache_destroy(cgw_cache); 1016 return -ENOBUFS; 1017 } 1018 1019 /* Only the first call to __rtnl_register can fail */ 1020 __rtnl_register(PF_CAN, RTM_NEWROUTE, cgw_create_job, NULL, NULL); 1021 __rtnl_register(PF_CAN, RTM_DELROUTE, cgw_remove_job, NULL, NULL); 1022 1023 return 0; 1024 } 1025 1026 static __exit void cgw_module_exit(void) 1027 { 1028 rtnl_unregister_all(PF_CAN); 1029 1030 unregister_netdevice_notifier(¬ifier); 1031 1032 rtnl_lock(); 1033 cgw_remove_all_jobs(); 1034 rtnl_unlock(); 1035 1036 rcu_barrier(); /* Wait for completion of call_rcu()'s */ 1037 1038 kmem_cache_destroy(cgw_cache); 1039 } 1040 1041 module_init(cgw_module_init); 1042 module_exit(cgw_module_exit); 1043