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 }; 114 115 116 /* 117 * So far we just support CAN -> CAN routing and frame modifications. 118 * 119 * The internal can_can_gw structure contains data and attributes for 120 * a CAN -> CAN gateway job. 121 */ 122 struct can_can_gw { 123 struct can_filter filter; 124 int src_idx; 125 int dst_idx; 126 }; 127 128 /* list entry for CAN gateways jobs */ 129 struct cgw_job { 130 struct hlist_node list; 131 struct rcu_head rcu; 132 u32 handled_frames; 133 u32 dropped_frames; 134 u32 deleted_frames; 135 struct cf_mod mod; 136 union { 137 /* CAN frame data source */ 138 struct net_device *dev; 139 } src; 140 union { 141 /* CAN frame data destination */ 142 struct net_device *dev; 143 } dst; 144 union { 145 struct can_can_gw ccgw; 146 /* tbc */ 147 }; 148 u8 gwtype; 149 u8 limit_hops; 150 u16 flags; 151 }; 152 153 /* modification functions that are invoked in the hot path in can_can_gw_rcv */ 154 155 #define MODFUNC(func, op) static void func(struct can_frame *cf, \ 156 struct cf_mod *mod) { op ; } 157 158 MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id) 159 MODFUNC(mod_and_dlc, cf->can_dlc &= mod->modframe.and.can_dlc) 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_dlc, cf->can_dlc |= mod->modframe.or.can_dlc) 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_dlc, cf->can_dlc ^= mod->modframe.xor.can_dlc) 166 MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data) 167 MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id) 168 MODFUNC(mod_set_dlc, cf->can_dlc = mod->modframe.set.can_dlc) 169 MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data) 170 171 static inline void canframecpy(struct can_frame *dst, struct can_frame *src) 172 { 173 /* 174 * Copy the struct members separately to ensure that no uninitialized 175 * data are copied in the 3 bytes hole of the struct. This is needed 176 * to make easy compares of the data in the struct cf_mod. 177 */ 178 179 dst->can_id = src->can_id; 180 dst->can_dlc = src->can_dlc; 181 *(u64 *)dst->data = *(u64 *)src->data; 182 } 183 184 static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re) 185 { 186 /* 187 * absolute dlc values 0 .. 7 => 0 .. 7, e.g. data [0] 188 * relative to received dlc -1 .. -8 : 189 * e.g. for received dlc = 8 190 * -1 => index = 7 (data[7]) 191 * -3 => index = 5 (data[5]) 192 * -8 => index = 0 (data[0]) 193 */ 194 195 if (fr > -9 && fr < 8 && 196 to > -9 && to < 8 && 197 re > -9 && re < 8) 198 return 0; 199 else 200 return -EINVAL; 201 } 202 203 static inline int calc_idx(int idx, int rx_dlc) 204 { 205 if (idx < 0) 206 return rx_dlc + idx; 207 else 208 return idx; 209 } 210 211 static void cgw_csum_xor_rel(struct can_frame *cf, struct cgw_csum_xor *xor) 212 { 213 int from = calc_idx(xor->from_idx, cf->can_dlc); 214 int to = calc_idx(xor->to_idx, cf->can_dlc); 215 int res = calc_idx(xor->result_idx, cf->can_dlc); 216 u8 val = xor->init_xor_val; 217 int i; 218 219 if (from < 0 || to < 0 || res < 0) 220 return; 221 222 if (from <= to) { 223 for (i = from; i <= to; i++) 224 val ^= cf->data[i]; 225 } else { 226 for (i = from; i >= to; i--) 227 val ^= cf->data[i]; 228 } 229 230 cf->data[res] = val; 231 } 232 233 static void cgw_csum_xor_pos(struct can_frame *cf, struct cgw_csum_xor *xor) 234 { 235 u8 val = xor->init_xor_val; 236 int i; 237 238 for (i = xor->from_idx; i <= xor->to_idx; i++) 239 val ^= cf->data[i]; 240 241 cf->data[xor->result_idx] = val; 242 } 243 244 static void cgw_csum_xor_neg(struct can_frame *cf, struct cgw_csum_xor *xor) 245 { 246 u8 val = xor->init_xor_val; 247 int i; 248 249 for (i = xor->from_idx; i >= xor->to_idx; i--) 250 val ^= cf->data[i]; 251 252 cf->data[xor->result_idx] = val; 253 } 254 255 static void cgw_csum_crc8_rel(struct can_frame *cf, struct cgw_csum_crc8 *crc8) 256 { 257 int from = calc_idx(crc8->from_idx, cf->can_dlc); 258 int to = calc_idx(crc8->to_idx, cf->can_dlc); 259 int res = calc_idx(crc8->result_idx, cf->can_dlc); 260 u8 crc = crc8->init_crc_val; 261 int i; 262 263 if (from < 0 || to < 0 || res < 0) 264 return; 265 266 if (from <= to) { 267 for (i = crc8->from_idx; i <= crc8->to_idx; i++) 268 crc = crc8->crctab[crc^cf->data[i]]; 269 } else { 270 for (i = crc8->from_idx; i >= crc8->to_idx; i--) 271 crc = crc8->crctab[crc^cf->data[i]]; 272 } 273 274 switch (crc8->profile) { 275 276 case CGW_CRC8PRF_1U8: 277 crc = crc8->crctab[crc^crc8->profile_data[0]]; 278 break; 279 280 case CGW_CRC8PRF_16U8: 281 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]]; 282 break; 283 284 case CGW_CRC8PRF_SFFID_XOR: 285 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^ 286 (cf->can_id >> 8 & 0xFF)]; 287 break; 288 289 } 290 291 cf->data[crc8->result_idx] = crc^crc8->final_xor_val; 292 } 293 294 static void cgw_csum_crc8_pos(struct can_frame *cf, struct cgw_csum_crc8 *crc8) 295 { 296 u8 crc = crc8->init_crc_val; 297 int i; 298 299 for (i = crc8->from_idx; i <= crc8->to_idx; i++) 300 crc = crc8->crctab[crc^cf->data[i]]; 301 302 switch (crc8->profile) { 303 304 case CGW_CRC8PRF_1U8: 305 crc = crc8->crctab[crc^crc8->profile_data[0]]; 306 break; 307 308 case CGW_CRC8PRF_16U8: 309 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]]; 310 break; 311 312 case CGW_CRC8PRF_SFFID_XOR: 313 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^ 314 (cf->can_id >> 8 & 0xFF)]; 315 break; 316 } 317 318 cf->data[crc8->result_idx] = crc^crc8->final_xor_val; 319 } 320 321 static void cgw_csum_crc8_neg(struct can_frame *cf, struct cgw_csum_crc8 *crc8) 322 { 323 u8 crc = crc8->init_crc_val; 324 int i; 325 326 for (i = crc8->from_idx; i >= crc8->to_idx; i--) 327 crc = crc8->crctab[crc^cf->data[i]]; 328 329 switch (crc8->profile) { 330 331 case CGW_CRC8PRF_1U8: 332 crc = crc8->crctab[crc^crc8->profile_data[0]]; 333 break; 334 335 case CGW_CRC8PRF_16U8: 336 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]]; 337 break; 338 339 case CGW_CRC8PRF_SFFID_XOR: 340 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^ 341 (cf->can_id >> 8 & 0xFF)]; 342 break; 343 } 344 345 cf->data[crc8->result_idx] = crc^crc8->final_xor_val; 346 } 347 348 /* the receive & process & send function */ 349 static void can_can_gw_rcv(struct sk_buff *skb, void *data) 350 { 351 struct cgw_job *gwj = (struct cgw_job *)data; 352 struct can_frame *cf; 353 struct sk_buff *nskb; 354 int modidx = 0; 355 356 /* 357 * Do not handle CAN frames routed more than 'max_hops' times. 358 * In general we should never catch this delimiter which is intended 359 * to cover a misconfiguration protection (e.g. circular CAN routes). 360 * 361 * The Controller Area Network controllers only accept CAN frames with 362 * correct CRCs - which are not visible in the controller registers. 363 * According to skbuff.h documentation the csum_start element for IP 364 * checksums is undefined/unused when ip_summed == CHECKSUM_UNNECESSARY. 365 * Only CAN skbs can be processed here which already have this property. 366 */ 367 368 #define cgw_hops(skb) ((skb)->csum_start) 369 370 BUG_ON(skb->ip_summed != CHECKSUM_UNNECESSARY); 371 372 if (cgw_hops(skb) >= max_hops) { 373 /* indicate deleted frames due to misconfiguration */ 374 gwj->deleted_frames++; 375 return; 376 } 377 378 if (!(gwj->dst.dev->flags & IFF_UP)) { 379 gwj->dropped_frames++; 380 return; 381 } 382 383 /* is sending the skb back to the incoming interface not allowed? */ 384 if (!(gwj->flags & CGW_FLAGS_CAN_IIF_TX_OK) && 385 can_skb_prv(skb)->ifindex == gwj->dst.dev->ifindex) 386 return; 387 388 /* 389 * clone the given skb, which has not been done in can_rcv() 390 * 391 * When there is at least one modification function activated, 392 * we need to copy the skb as we want to modify skb->data. 393 */ 394 if (gwj->mod.modfunc[0]) 395 nskb = skb_copy(skb, GFP_ATOMIC); 396 else 397 nskb = skb_clone(skb, GFP_ATOMIC); 398 399 if (!nskb) { 400 gwj->dropped_frames++; 401 return; 402 } 403 404 /* put the incremented hop counter in the cloned skb */ 405 cgw_hops(nskb) = cgw_hops(skb) + 1; 406 407 /* first processing of this CAN frame -> adjust to private hop limit */ 408 if (gwj->limit_hops && cgw_hops(nskb) == 1) 409 cgw_hops(nskb) = max_hops - gwj->limit_hops + 1; 410 411 nskb->dev = gwj->dst.dev; 412 413 /* pointer to modifiable CAN frame */ 414 cf = (struct can_frame *)nskb->data; 415 416 /* perform preprocessed modification functions if there are any */ 417 while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx]) 418 (*gwj->mod.modfunc[modidx++])(cf, &gwj->mod); 419 420 /* check for checksum updates when the CAN frame has been modified */ 421 if (modidx) { 422 if (gwj->mod.csumfunc.crc8) 423 (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8); 424 425 if (gwj->mod.csumfunc.xor) 426 (*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor); 427 } 428 429 /* clear the skb timestamp if not configured the other way */ 430 if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP)) 431 nskb->tstamp.tv64 = 0; 432 433 /* send to netdevice */ 434 if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO)) 435 gwj->dropped_frames++; 436 else 437 gwj->handled_frames++; 438 } 439 440 static inline int cgw_register_filter(struct cgw_job *gwj) 441 { 442 return can_rx_register(gwj->src.dev, gwj->ccgw.filter.can_id, 443 gwj->ccgw.filter.can_mask, can_can_gw_rcv, 444 gwj, "gw"); 445 } 446 447 static inline void cgw_unregister_filter(struct cgw_job *gwj) 448 { 449 can_rx_unregister(gwj->src.dev, gwj->ccgw.filter.can_id, 450 gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj); 451 } 452 453 static int cgw_notifier(struct notifier_block *nb, 454 unsigned long msg, void *ptr) 455 { 456 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 457 458 if (!net_eq(dev_net(dev), &init_net)) 459 return NOTIFY_DONE; 460 if (dev->type != ARPHRD_CAN) 461 return NOTIFY_DONE; 462 463 if (msg == NETDEV_UNREGISTER) { 464 465 struct cgw_job *gwj = NULL; 466 struct hlist_node *nx; 467 468 ASSERT_RTNL(); 469 470 hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) { 471 472 if (gwj->src.dev == dev || gwj->dst.dev == dev) { 473 hlist_del(&gwj->list); 474 cgw_unregister_filter(gwj); 475 kmem_cache_free(cgw_cache, gwj); 476 } 477 } 478 } 479 480 return NOTIFY_DONE; 481 } 482 483 static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type, 484 u32 pid, u32 seq, int flags) 485 { 486 struct cgw_frame_mod mb; 487 struct rtcanmsg *rtcan; 488 struct nlmsghdr *nlh; 489 490 nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags); 491 if (!nlh) 492 return -EMSGSIZE; 493 494 rtcan = nlmsg_data(nlh); 495 rtcan->can_family = AF_CAN; 496 rtcan->gwtype = gwj->gwtype; 497 rtcan->flags = gwj->flags; 498 499 /* add statistics if available */ 500 501 if (gwj->handled_frames) { 502 if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0) 503 goto cancel; 504 } 505 506 if (gwj->dropped_frames) { 507 if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0) 508 goto cancel; 509 } 510 511 if (gwj->deleted_frames) { 512 if (nla_put_u32(skb, CGW_DELETED, gwj->deleted_frames) < 0) 513 goto cancel; 514 } 515 516 /* check non default settings of attributes */ 517 518 if (gwj->limit_hops) { 519 if (nla_put_u8(skb, CGW_LIM_HOPS, gwj->limit_hops) < 0) 520 goto cancel; 521 } 522 523 if (gwj->mod.modtype.and) { 524 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf)); 525 mb.modtype = gwj->mod.modtype.and; 526 if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0) 527 goto cancel; 528 } 529 530 if (gwj->mod.modtype.or) { 531 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf)); 532 mb.modtype = gwj->mod.modtype.or; 533 if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0) 534 goto cancel; 535 } 536 537 if (gwj->mod.modtype.xor) { 538 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf)); 539 mb.modtype = gwj->mod.modtype.xor; 540 if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0) 541 goto cancel; 542 } 543 544 if (gwj->mod.modtype.set) { 545 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf)); 546 mb.modtype = gwj->mod.modtype.set; 547 if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0) 548 goto cancel; 549 } 550 551 if (gwj->mod.csumfunc.crc8) { 552 if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN, 553 &gwj->mod.csum.crc8) < 0) 554 goto cancel; 555 } 556 557 if (gwj->mod.csumfunc.xor) { 558 if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN, 559 &gwj->mod.csum.xor) < 0) 560 goto cancel; 561 } 562 563 if (gwj->gwtype == CGW_TYPE_CAN_CAN) { 564 565 if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) { 566 if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter), 567 &gwj->ccgw.filter) < 0) 568 goto cancel; 569 } 570 571 if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0) 572 goto cancel; 573 574 if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0) 575 goto cancel; 576 } 577 578 nlmsg_end(skb, nlh); 579 return 0; 580 581 cancel: 582 nlmsg_cancel(skb, nlh); 583 return -EMSGSIZE; 584 } 585 586 /* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */ 587 static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb) 588 { 589 struct cgw_job *gwj = NULL; 590 int idx = 0; 591 int s_idx = cb->args[0]; 592 593 rcu_read_lock(); 594 hlist_for_each_entry_rcu(gwj, &cgw_list, list) { 595 if (idx < s_idx) 596 goto cont; 597 598 if (cgw_put_job(skb, gwj, RTM_NEWROUTE, NETLINK_CB(cb->skb).portid, 599 cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0) 600 break; 601 cont: 602 idx++; 603 } 604 rcu_read_unlock(); 605 606 cb->args[0] = idx; 607 608 return skb->len; 609 } 610 611 static const struct nla_policy cgw_policy[CGW_MAX+1] = { 612 [CGW_MOD_AND] = { .len = sizeof(struct cgw_frame_mod) }, 613 [CGW_MOD_OR] = { .len = sizeof(struct cgw_frame_mod) }, 614 [CGW_MOD_XOR] = { .len = sizeof(struct cgw_frame_mod) }, 615 [CGW_MOD_SET] = { .len = sizeof(struct cgw_frame_mod) }, 616 [CGW_CS_XOR] = { .len = sizeof(struct cgw_csum_xor) }, 617 [CGW_CS_CRC8] = { .len = sizeof(struct cgw_csum_crc8) }, 618 [CGW_SRC_IF] = { .type = NLA_U32 }, 619 [CGW_DST_IF] = { .type = NLA_U32 }, 620 [CGW_FILTER] = { .len = sizeof(struct can_filter) }, 621 [CGW_LIM_HOPS] = { .type = NLA_U8 }, 622 }; 623 624 /* check for common and gwtype specific attributes */ 625 static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod, 626 u8 gwtype, void *gwtypeattr, u8 *limhops) 627 { 628 struct nlattr *tb[CGW_MAX+1]; 629 struct cgw_frame_mod mb; 630 int modidx = 0; 631 int err = 0; 632 633 /* initialize modification & checksum data space */ 634 memset(mod, 0, sizeof(*mod)); 635 636 err = nlmsg_parse(nlh, sizeof(struct rtcanmsg), tb, CGW_MAX, 637 cgw_policy); 638 if (err < 0) 639 return err; 640 641 if (tb[CGW_LIM_HOPS]) { 642 *limhops = nla_get_u8(tb[CGW_LIM_HOPS]); 643 644 if (*limhops < 1 || *limhops > max_hops) 645 return -EINVAL; 646 } 647 648 /* check for AND/OR/XOR/SET modifications */ 649 650 if (tb[CGW_MOD_AND]) { 651 nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN); 652 653 canframecpy(&mod->modframe.and, &mb.cf); 654 mod->modtype.and = mb.modtype; 655 656 if (mb.modtype & CGW_MOD_ID) 657 mod->modfunc[modidx++] = mod_and_id; 658 659 if (mb.modtype & CGW_MOD_DLC) 660 mod->modfunc[modidx++] = mod_and_dlc; 661 662 if (mb.modtype & CGW_MOD_DATA) 663 mod->modfunc[modidx++] = mod_and_data; 664 } 665 666 if (tb[CGW_MOD_OR]) { 667 nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN); 668 669 canframecpy(&mod->modframe.or, &mb.cf); 670 mod->modtype.or = mb.modtype; 671 672 if (mb.modtype & CGW_MOD_ID) 673 mod->modfunc[modidx++] = mod_or_id; 674 675 if (mb.modtype & CGW_MOD_DLC) 676 mod->modfunc[modidx++] = mod_or_dlc; 677 678 if (mb.modtype & CGW_MOD_DATA) 679 mod->modfunc[modidx++] = mod_or_data; 680 } 681 682 if (tb[CGW_MOD_XOR]) { 683 nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN); 684 685 canframecpy(&mod->modframe.xor, &mb.cf); 686 mod->modtype.xor = mb.modtype; 687 688 if (mb.modtype & CGW_MOD_ID) 689 mod->modfunc[modidx++] = mod_xor_id; 690 691 if (mb.modtype & CGW_MOD_DLC) 692 mod->modfunc[modidx++] = mod_xor_dlc; 693 694 if (mb.modtype & CGW_MOD_DATA) 695 mod->modfunc[modidx++] = mod_xor_data; 696 } 697 698 if (tb[CGW_MOD_SET]) { 699 nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN); 700 701 canframecpy(&mod->modframe.set, &mb.cf); 702 mod->modtype.set = mb.modtype; 703 704 if (mb.modtype & CGW_MOD_ID) 705 mod->modfunc[modidx++] = mod_set_id; 706 707 if (mb.modtype & CGW_MOD_DLC) 708 mod->modfunc[modidx++] = mod_set_dlc; 709 710 if (mb.modtype & CGW_MOD_DATA) 711 mod->modfunc[modidx++] = mod_set_data; 712 } 713 714 /* check for checksum operations after CAN frame modifications */ 715 if (modidx) { 716 717 if (tb[CGW_CS_CRC8]) { 718 struct cgw_csum_crc8 *c = nla_data(tb[CGW_CS_CRC8]); 719 720 err = cgw_chk_csum_parms(c->from_idx, c->to_idx, 721 c->result_idx); 722 if (err) 723 return err; 724 725 nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8], 726 CGW_CS_CRC8_LEN); 727 728 /* 729 * select dedicated processing function to reduce 730 * runtime operations in receive hot path. 731 */ 732 if (c->from_idx < 0 || c->to_idx < 0 || 733 c->result_idx < 0) 734 mod->csumfunc.crc8 = cgw_csum_crc8_rel; 735 else if (c->from_idx <= c->to_idx) 736 mod->csumfunc.crc8 = cgw_csum_crc8_pos; 737 else 738 mod->csumfunc.crc8 = cgw_csum_crc8_neg; 739 } 740 741 if (tb[CGW_CS_XOR]) { 742 struct cgw_csum_xor *c = nla_data(tb[CGW_CS_XOR]); 743 744 err = cgw_chk_csum_parms(c->from_idx, c->to_idx, 745 c->result_idx); 746 if (err) 747 return err; 748 749 nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR], 750 CGW_CS_XOR_LEN); 751 752 /* 753 * select dedicated processing function to reduce 754 * runtime operations in receive hot path. 755 */ 756 if (c->from_idx < 0 || c->to_idx < 0 || 757 c->result_idx < 0) 758 mod->csumfunc.xor = cgw_csum_xor_rel; 759 else if (c->from_idx <= c->to_idx) 760 mod->csumfunc.xor = cgw_csum_xor_pos; 761 else 762 mod->csumfunc.xor = cgw_csum_xor_neg; 763 } 764 } 765 766 if (gwtype == CGW_TYPE_CAN_CAN) { 767 768 /* check CGW_TYPE_CAN_CAN specific attributes */ 769 770 struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr; 771 memset(ccgw, 0, sizeof(*ccgw)); 772 773 /* check for can_filter in attributes */ 774 if (tb[CGW_FILTER]) 775 nla_memcpy(&ccgw->filter, tb[CGW_FILTER], 776 sizeof(struct can_filter)); 777 778 err = -ENODEV; 779 780 /* specifying two interfaces is mandatory */ 781 if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF]) 782 return err; 783 784 ccgw->src_idx = nla_get_u32(tb[CGW_SRC_IF]); 785 ccgw->dst_idx = nla_get_u32(tb[CGW_DST_IF]); 786 787 /* both indices set to 0 for flushing all routing entries */ 788 if (!ccgw->src_idx && !ccgw->dst_idx) 789 return 0; 790 791 /* only one index set to 0 is an error */ 792 if (!ccgw->src_idx || !ccgw->dst_idx) 793 return err; 794 } 795 796 /* add the checks for other gwtypes here */ 797 798 return 0; 799 } 800 801 static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh) 802 { 803 struct rtcanmsg *r; 804 struct cgw_job *gwj; 805 u8 limhops = 0; 806 int err = 0; 807 808 if (!netlink_capable(skb, CAP_NET_ADMIN)) 809 return -EPERM; 810 811 if (nlmsg_len(nlh) < sizeof(*r)) 812 return -EINVAL; 813 814 r = nlmsg_data(nlh); 815 if (r->can_family != AF_CAN) 816 return -EPFNOSUPPORT; 817 818 /* so far we only support CAN -> CAN routings */ 819 if (r->gwtype != CGW_TYPE_CAN_CAN) 820 return -EINVAL; 821 822 gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL); 823 if (!gwj) 824 return -ENOMEM; 825 826 gwj->handled_frames = 0; 827 gwj->dropped_frames = 0; 828 gwj->deleted_frames = 0; 829 gwj->flags = r->flags; 830 gwj->gwtype = r->gwtype; 831 832 err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw, 833 &limhops); 834 if (err < 0) 835 goto out; 836 837 err = -ENODEV; 838 839 /* ifindex == 0 is not allowed for job creation */ 840 if (!gwj->ccgw.src_idx || !gwj->ccgw.dst_idx) 841 goto out; 842 843 gwj->src.dev = __dev_get_by_index(&init_net, gwj->ccgw.src_idx); 844 845 if (!gwj->src.dev) 846 goto out; 847 848 if (gwj->src.dev->type != ARPHRD_CAN) 849 goto out; 850 851 gwj->dst.dev = __dev_get_by_index(&init_net, gwj->ccgw.dst_idx); 852 853 if (!gwj->dst.dev) 854 goto out; 855 856 if (gwj->dst.dev->type != ARPHRD_CAN) 857 goto out; 858 859 gwj->limit_hops = limhops; 860 861 ASSERT_RTNL(); 862 863 err = cgw_register_filter(gwj); 864 if (!err) 865 hlist_add_head_rcu(&gwj->list, &cgw_list); 866 out: 867 if (err) 868 kmem_cache_free(cgw_cache, gwj); 869 870 return err; 871 } 872 873 static void cgw_remove_all_jobs(void) 874 { 875 struct cgw_job *gwj = NULL; 876 struct hlist_node *nx; 877 878 ASSERT_RTNL(); 879 880 hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) { 881 hlist_del(&gwj->list); 882 cgw_unregister_filter(gwj); 883 kmem_cache_free(cgw_cache, gwj); 884 } 885 } 886 887 static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh) 888 { 889 struct cgw_job *gwj = NULL; 890 struct hlist_node *nx; 891 struct rtcanmsg *r; 892 struct cf_mod mod; 893 struct can_can_gw ccgw; 894 u8 limhops = 0; 895 int err = 0; 896 897 if (!netlink_capable(skb, CAP_NET_ADMIN)) 898 return -EPERM; 899 900 if (nlmsg_len(nlh) < sizeof(*r)) 901 return -EINVAL; 902 903 r = nlmsg_data(nlh); 904 if (r->can_family != AF_CAN) 905 return -EPFNOSUPPORT; 906 907 /* so far we only support CAN -> CAN routings */ 908 if (r->gwtype != CGW_TYPE_CAN_CAN) 909 return -EINVAL; 910 911 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops); 912 if (err < 0) 913 return err; 914 915 /* two interface indices both set to 0 => remove all entries */ 916 if (!ccgw.src_idx && !ccgw.dst_idx) { 917 cgw_remove_all_jobs(); 918 return 0; 919 } 920 921 err = -EINVAL; 922 923 ASSERT_RTNL(); 924 925 /* remove only the first matching entry */ 926 hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) { 927 928 if (gwj->flags != r->flags) 929 continue; 930 931 if (gwj->limit_hops != limhops) 932 continue; 933 934 if (memcmp(&gwj->mod, &mod, sizeof(mod))) 935 continue; 936 937 /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */ 938 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw))) 939 continue; 940 941 hlist_del(&gwj->list); 942 cgw_unregister_filter(gwj); 943 kmem_cache_free(cgw_cache, gwj); 944 err = 0; 945 break; 946 } 947 948 return err; 949 } 950 951 static __init int cgw_module_init(void) 952 { 953 /* sanitize given module parameter */ 954 max_hops = clamp_t(unsigned int, max_hops, CGW_MIN_HOPS, CGW_MAX_HOPS); 955 956 pr_info("can: netlink gateway (rev " CAN_GW_VERSION ") max_hops=%d\n", 957 max_hops); 958 959 cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job), 960 0, 0, NULL); 961 962 if (!cgw_cache) 963 return -ENOMEM; 964 965 /* set notifier */ 966 notifier.notifier_call = cgw_notifier; 967 register_netdevice_notifier(¬ifier); 968 969 if (__rtnl_register(PF_CAN, RTM_GETROUTE, NULL, cgw_dump_jobs, NULL)) { 970 unregister_netdevice_notifier(¬ifier); 971 kmem_cache_destroy(cgw_cache); 972 return -ENOBUFS; 973 } 974 975 /* Only the first call to __rtnl_register can fail */ 976 __rtnl_register(PF_CAN, RTM_NEWROUTE, cgw_create_job, NULL, NULL); 977 __rtnl_register(PF_CAN, RTM_DELROUTE, cgw_remove_job, NULL, NULL); 978 979 return 0; 980 } 981 982 static __exit void cgw_module_exit(void) 983 { 984 rtnl_unregister_all(PF_CAN); 985 986 unregister_netdevice_notifier(¬ifier); 987 988 rtnl_lock(); 989 cgw_remove_all_jobs(); 990 rtnl_unlock(); 991 992 rcu_barrier(); /* Wait for completion of call_rcu()'s */ 993 994 kmem_cache_destroy(cgw_cache); 995 } 996 997 module_init(cgw_module_init); 998 module_exit(cgw_module_exit); 999