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 u16 flags; 150 }; 151 152 /* modification functions that are invoked in the hot path in can_can_gw_rcv */ 153 154 #define MODFUNC(func, op) static void func(struct can_frame *cf, \ 155 struct cf_mod *mod) { op ; } 156 157 MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id) 158 MODFUNC(mod_and_dlc, cf->can_dlc &= mod->modframe.and.can_dlc) 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_dlc, cf->can_dlc |= mod->modframe.or.can_dlc) 162 MODFUNC(mod_or_data, *(u64 *)cf->data |= *(u64 *)mod->modframe.or.data) 163 MODFUNC(mod_xor_id, cf->can_id ^= mod->modframe.xor.can_id) 164 MODFUNC(mod_xor_dlc, cf->can_dlc ^= mod->modframe.xor.can_dlc) 165 MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data) 166 MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id) 167 MODFUNC(mod_set_dlc, cf->can_dlc = mod->modframe.set.can_dlc) 168 MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data) 169 170 static inline void canframecpy(struct can_frame *dst, struct can_frame *src) 171 { 172 /* 173 * Copy the struct members separately to ensure that no uninitialized 174 * data are copied in the 3 bytes hole of the struct. This is needed 175 * to make easy compares of the data in the struct cf_mod. 176 */ 177 178 dst->can_id = src->can_id; 179 dst->can_dlc = src->can_dlc; 180 *(u64 *)dst->data = *(u64 *)src->data; 181 } 182 183 static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re) 184 { 185 /* 186 * absolute dlc values 0 .. 7 => 0 .. 7, e.g. data [0] 187 * relative to received dlc -1 .. -8 : 188 * e.g. for received dlc = 8 189 * -1 => index = 7 (data[7]) 190 * -3 => index = 5 (data[5]) 191 * -8 => index = 0 (data[0]) 192 */ 193 194 if (fr > -9 && fr < 8 && 195 to > -9 && to < 8 && 196 re > -9 && re < 8) 197 return 0; 198 else 199 return -EINVAL; 200 } 201 202 static inline int calc_idx(int idx, int rx_dlc) 203 { 204 if (idx < 0) 205 return rx_dlc + idx; 206 else 207 return idx; 208 } 209 210 static void cgw_csum_xor_rel(struct can_frame *cf, struct cgw_csum_xor *xor) 211 { 212 int from = calc_idx(xor->from_idx, cf->can_dlc); 213 int to = calc_idx(xor->to_idx, cf->can_dlc); 214 int res = calc_idx(xor->result_idx, cf->can_dlc); 215 u8 val = xor->init_xor_val; 216 int i; 217 218 if (from < 0 || to < 0 || res < 0) 219 return; 220 221 if (from <= to) { 222 for (i = from; i <= to; i++) 223 val ^= cf->data[i]; 224 } else { 225 for (i = from; i >= to; i--) 226 val ^= cf->data[i]; 227 } 228 229 cf->data[res] = val; 230 } 231 232 static void cgw_csum_xor_pos(struct can_frame *cf, struct cgw_csum_xor *xor) 233 { 234 u8 val = xor->init_xor_val; 235 int i; 236 237 for (i = xor->from_idx; i <= xor->to_idx; i++) 238 val ^= cf->data[i]; 239 240 cf->data[xor->result_idx] = val; 241 } 242 243 static void cgw_csum_xor_neg(struct can_frame *cf, struct cgw_csum_xor *xor) 244 { 245 u8 val = xor->init_xor_val; 246 int i; 247 248 for (i = xor->from_idx; i >= xor->to_idx; i--) 249 val ^= cf->data[i]; 250 251 cf->data[xor->result_idx] = val; 252 } 253 254 static void cgw_csum_crc8_rel(struct can_frame *cf, struct cgw_csum_crc8 *crc8) 255 { 256 int from = calc_idx(crc8->from_idx, cf->can_dlc); 257 int to = calc_idx(crc8->to_idx, cf->can_dlc); 258 int res = calc_idx(crc8->result_idx, cf->can_dlc); 259 u8 crc = crc8->init_crc_val; 260 int i; 261 262 if (from < 0 || to < 0 || res < 0) 263 return; 264 265 if (from <= to) { 266 for (i = crc8->from_idx; i <= crc8->to_idx; i++) 267 crc = crc8->crctab[crc^cf->data[i]]; 268 } else { 269 for (i = crc8->from_idx; i >= crc8->to_idx; i--) 270 crc = crc8->crctab[crc^cf->data[i]]; 271 } 272 273 switch (crc8->profile) { 274 275 case CGW_CRC8PRF_1U8: 276 crc = crc8->crctab[crc^crc8->profile_data[0]]; 277 break; 278 279 case CGW_CRC8PRF_16U8: 280 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]]; 281 break; 282 283 case CGW_CRC8PRF_SFFID_XOR: 284 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^ 285 (cf->can_id >> 8 & 0xFF)]; 286 break; 287 288 } 289 290 cf->data[crc8->result_idx] = crc^crc8->final_xor_val; 291 } 292 293 static void cgw_csum_crc8_pos(struct can_frame *cf, struct cgw_csum_crc8 *crc8) 294 { 295 u8 crc = crc8->init_crc_val; 296 int i; 297 298 for (i = crc8->from_idx; i <= crc8->to_idx; i++) 299 crc = crc8->crctab[crc^cf->data[i]]; 300 301 switch (crc8->profile) { 302 303 case CGW_CRC8PRF_1U8: 304 crc = crc8->crctab[crc^crc8->profile_data[0]]; 305 break; 306 307 case CGW_CRC8PRF_16U8: 308 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]]; 309 break; 310 311 case CGW_CRC8PRF_SFFID_XOR: 312 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^ 313 (cf->can_id >> 8 & 0xFF)]; 314 break; 315 } 316 317 cf->data[crc8->result_idx] = crc^crc8->final_xor_val; 318 } 319 320 static void cgw_csum_crc8_neg(struct can_frame *cf, struct cgw_csum_crc8 *crc8) 321 { 322 u8 crc = crc8->init_crc_val; 323 int i; 324 325 for (i = crc8->from_idx; i >= crc8->to_idx; i--) 326 crc = crc8->crctab[crc^cf->data[i]]; 327 328 switch (crc8->profile) { 329 330 case CGW_CRC8PRF_1U8: 331 crc = crc8->crctab[crc^crc8->profile_data[0]]; 332 break; 333 334 case CGW_CRC8PRF_16U8: 335 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]]; 336 break; 337 338 case CGW_CRC8PRF_SFFID_XOR: 339 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^ 340 (cf->can_id >> 8 & 0xFF)]; 341 break; 342 } 343 344 cf->data[crc8->result_idx] = crc^crc8->final_xor_val; 345 } 346 347 /* the receive & process & send function */ 348 static void can_can_gw_rcv(struct sk_buff *skb, void *data) 349 { 350 struct cgw_job *gwj = (struct cgw_job *)data; 351 struct can_frame *cf; 352 struct sk_buff *nskb; 353 int modidx = 0; 354 355 /* 356 * Do not handle CAN frames routed more than 'max_hops' times. 357 * In general we should never catch this delimiter which is intended 358 * to cover a misconfiguration protection (e.g. circular CAN routes). 359 * 360 * The Controller Area Network controllers only accept CAN frames with 361 * correct CRCs - which are not visible in the controller registers. 362 * According to skbuff.h documentation the csum_start element for IP 363 * checksums is undefined/unsued when ip_summed == CHECKSUM_UNNECESSARY. 364 * Only CAN skbs can be processed here which already have this property. 365 */ 366 367 #define cgw_hops(skb) ((skb)->csum_start) 368 369 BUG_ON(skb->ip_summed != CHECKSUM_UNNECESSARY); 370 371 if (cgw_hops(skb) >= max_hops) { 372 /* indicate deleted frames due to misconfiguration */ 373 gwj->deleted_frames++; 374 return; 375 } 376 377 if (!(gwj->dst.dev->flags & IFF_UP)) { 378 gwj->dropped_frames++; 379 return; 380 } 381 382 /* is sending the skb back to the incoming interface not allowed? */ 383 if (!(gwj->flags & CGW_FLAGS_CAN_IIF_TX_OK) && 384 can_skb_prv(skb)->ifindex == gwj->dst.dev->ifindex) 385 return; 386 387 /* 388 * clone the given skb, which has not been done in can_rcv() 389 * 390 * When there is at least one modification function activated, 391 * we need to copy the skb as we want to modify skb->data. 392 */ 393 if (gwj->mod.modfunc[0]) 394 nskb = skb_copy(skb, GFP_ATOMIC); 395 else 396 nskb = skb_clone(skb, GFP_ATOMIC); 397 398 if (!nskb) { 399 gwj->dropped_frames++; 400 return; 401 } 402 403 /* put the incremented hop counter in the cloned skb */ 404 cgw_hops(nskb) = cgw_hops(skb) + 1; 405 nskb->dev = gwj->dst.dev; 406 407 /* pointer to modifiable CAN frame */ 408 cf = (struct can_frame *)nskb->data; 409 410 /* perform preprocessed modification functions if there are any */ 411 while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx]) 412 (*gwj->mod.modfunc[modidx++])(cf, &gwj->mod); 413 414 /* check for checksum updates when the CAN frame has been modified */ 415 if (modidx) { 416 if (gwj->mod.csumfunc.crc8) 417 (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8); 418 419 if (gwj->mod.csumfunc.xor) 420 (*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor); 421 } 422 423 /* clear the skb timestamp if not configured the other way */ 424 if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP)) 425 nskb->tstamp.tv64 = 0; 426 427 /* send to netdevice */ 428 if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO)) 429 gwj->dropped_frames++; 430 else 431 gwj->handled_frames++; 432 } 433 434 static inline int cgw_register_filter(struct cgw_job *gwj) 435 { 436 return can_rx_register(gwj->src.dev, gwj->ccgw.filter.can_id, 437 gwj->ccgw.filter.can_mask, can_can_gw_rcv, 438 gwj, "gw"); 439 } 440 441 static inline void cgw_unregister_filter(struct cgw_job *gwj) 442 { 443 can_rx_unregister(gwj->src.dev, gwj->ccgw.filter.can_id, 444 gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj); 445 } 446 447 static int cgw_notifier(struct notifier_block *nb, 448 unsigned long msg, void *data) 449 { 450 struct net_device *dev = (struct net_device *)data; 451 452 if (!net_eq(dev_net(dev), &init_net)) 453 return NOTIFY_DONE; 454 if (dev->type != ARPHRD_CAN) 455 return NOTIFY_DONE; 456 457 if (msg == NETDEV_UNREGISTER) { 458 459 struct cgw_job *gwj = NULL; 460 struct hlist_node *nx; 461 462 ASSERT_RTNL(); 463 464 hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) { 465 466 if (gwj->src.dev == dev || gwj->dst.dev == dev) { 467 hlist_del(&gwj->list); 468 cgw_unregister_filter(gwj); 469 kmem_cache_free(cgw_cache, gwj); 470 } 471 } 472 } 473 474 return NOTIFY_DONE; 475 } 476 477 static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type, 478 u32 pid, u32 seq, int flags) 479 { 480 struct cgw_frame_mod mb; 481 struct rtcanmsg *rtcan; 482 struct nlmsghdr *nlh; 483 484 nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags); 485 if (!nlh) 486 return -EMSGSIZE; 487 488 rtcan = nlmsg_data(nlh); 489 rtcan->can_family = AF_CAN; 490 rtcan->gwtype = gwj->gwtype; 491 rtcan->flags = gwj->flags; 492 493 /* add statistics if available */ 494 495 if (gwj->handled_frames) { 496 if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0) 497 goto cancel; 498 } 499 500 if (gwj->dropped_frames) { 501 if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0) 502 goto cancel; 503 } 504 505 if (gwj->deleted_frames) { 506 if (nla_put_u32(skb, CGW_DELETED, gwj->deleted_frames) < 0) 507 goto cancel; 508 } 509 510 /* check non default settings of attributes */ 511 512 if (gwj->mod.modtype.and) { 513 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf)); 514 mb.modtype = gwj->mod.modtype.and; 515 if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0) 516 goto cancel; 517 } 518 519 if (gwj->mod.modtype.or) { 520 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf)); 521 mb.modtype = gwj->mod.modtype.or; 522 if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0) 523 goto cancel; 524 } 525 526 if (gwj->mod.modtype.xor) { 527 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf)); 528 mb.modtype = gwj->mod.modtype.xor; 529 if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0) 530 goto cancel; 531 } 532 533 if (gwj->mod.modtype.set) { 534 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf)); 535 mb.modtype = gwj->mod.modtype.set; 536 if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0) 537 goto cancel; 538 } 539 540 if (gwj->mod.csumfunc.crc8) { 541 if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN, 542 &gwj->mod.csum.crc8) < 0) 543 goto cancel; 544 } 545 546 if (gwj->mod.csumfunc.xor) { 547 if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN, 548 &gwj->mod.csum.xor) < 0) 549 goto cancel; 550 } 551 552 if (gwj->gwtype == CGW_TYPE_CAN_CAN) { 553 554 if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) { 555 if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter), 556 &gwj->ccgw.filter) < 0) 557 goto cancel; 558 } 559 560 if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0) 561 goto cancel; 562 563 if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0) 564 goto cancel; 565 } 566 567 return nlmsg_end(skb, nlh); 568 569 cancel: 570 nlmsg_cancel(skb, nlh); 571 return -EMSGSIZE; 572 } 573 574 /* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */ 575 static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb) 576 { 577 struct cgw_job *gwj = NULL; 578 int idx = 0; 579 int s_idx = cb->args[0]; 580 581 rcu_read_lock(); 582 hlist_for_each_entry_rcu(gwj, &cgw_list, list) { 583 if (idx < s_idx) 584 goto cont; 585 586 if (cgw_put_job(skb, gwj, RTM_NEWROUTE, NETLINK_CB(cb->skb).portid, 587 cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0) 588 break; 589 cont: 590 idx++; 591 } 592 rcu_read_unlock(); 593 594 cb->args[0] = idx; 595 596 return skb->len; 597 } 598 599 static const struct nla_policy cgw_policy[CGW_MAX+1] = { 600 [CGW_MOD_AND] = { .len = sizeof(struct cgw_frame_mod) }, 601 [CGW_MOD_OR] = { .len = sizeof(struct cgw_frame_mod) }, 602 [CGW_MOD_XOR] = { .len = sizeof(struct cgw_frame_mod) }, 603 [CGW_MOD_SET] = { .len = sizeof(struct cgw_frame_mod) }, 604 [CGW_CS_XOR] = { .len = sizeof(struct cgw_csum_xor) }, 605 [CGW_CS_CRC8] = { .len = sizeof(struct cgw_csum_crc8) }, 606 [CGW_SRC_IF] = { .type = NLA_U32 }, 607 [CGW_DST_IF] = { .type = NLA_U32 }, 608 [CGW_FILTER] = { .len = sizeof(struct can_filter) }, 609 }; 610 611 /* check for common and gwtype specific attributes */ 612 static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod, 613 u8 gwtype, void *gwtypeattr) 614 { 615 struct nlattr *tb[CGW_MAX+1]; 616 struct cgw_frame_mod mb; 617 int modidx = 0; 618 int err = 0; 619 620 /* initialize modification & checksum data space */ 621 memset(mod, 0, sizeof(*mod)); 622 623 err = nlmsg_parse(nlh, sizeof(struct rtcanmsg), tb, CGW_MAX, 624 cgw_policy); 625 if (err < 0) 626 return err; 627 628 /* check for AND/OR/XOR/SET modifications */ 629 630 if (tb[CGW_MOD_AND]) { 631 nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN); 632 633 canframecpy(&mod->modframe.and, &mb.cf); 634 mod->modtype.and = mb.modtype; 635 636 if (mb.modtype & CGW_MOD_ID) 637 mod->modfunc[modidx++] = mod_and_id; 638 639 if (mb.modtype & CGW_MOD_DLC) 640 mod->modfunc[modidx++] = mod_and_dlc; 641 642 if (mb.modtype & CGW_MOD_DATA) 643 mod->modfunc[modidx++] = mod_and_data; 644 } 645 646 if (tb[CGW_MOD_OR]) { 647 nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN); 648 649 canframecpy(&mod->modframe.or, &mb.cf); 650 mod->modtype.or = mb.modtype; 651 652 if (mb.modtype & CGW_MOD_ID) 653 mod->modfunc[modidx++] = mod_or_id; 654 655 if (mb.modtype & CGW_MOD_DLC) 656 mod->modfunc[modidx++] = mod_or_dlc; 657 658 if (mb.modtype & CGW_MOD_DATA) 659 mod->modfunc[modidx++] = mod_or_data; 660 } 661 662 if (tb[CGW_MOD_XOR]) { 663 nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN); 664 665 canframecpy(&mod->modframe.xor, &mb.cf); 666 mod->modtype.xor = mb.modtype; 667 668 if (mb.modtype & CGW_MOD_ID) 669 mod->modfunc[modidx++] = mod_xor_id; 670 671 if (mb.modtype & CGW_MOD_DLC) 672 mod->modfunc[modidx++] = mod_xor_dlc; 673 674 if (mb.modtype & CGW_MOD_DATA) 675 mod->modfunc[modidx++] = mod_xor_data; 676 } 677 678 if (tb[CGW_MOD_SET]) { 679 nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN); 680 681 canframecpy(&mod->modframe.set, &mb.cf); 682 mod->modtype.set = mb.modtype; 683 684 if (mb.modtype & CGW_MOD_ID) 685 mod->modfunc[modidx++] = mod_set_id; 686 687 if (mb.modtype & CGW_MOD_DLC) 688 mod->modfunc[modidx++] = mod_set_dlc; 689 690 if (mb.modtype & CGW_MOD_DATA) 691 mod->modfunc[modidx++] = mod_set_data; 692 } 693 694 /* check for checksum operations after CAN frame modifications */ 695 if (modidx) { 696 697 if (tb[CGW_CS_CRC8]) { 698 struct cgw_csum_crc8 *c = nla_data(tb[CGW_CS_CRC8]); 699 700 err = cgw_chk_csum_parms(c->from_idx, c->to_idx, 701 c->result_idx); 702 if (err) 703 return err; 704 705 nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8], 706 CGW_CS_CRC8_LEN); 707 708 /* 709 * select dedicated processing function to reduce 710 * runtime operations in receive hot path. 711 */ 712 if (c->from_idx < 0 || c->to_idx < 0 || 713 c->result_idx < 0) 714 mod->csumfunc.crc8 = cgw_csum_crc8_rel; 715 else if (c->from_idx <= c->to_idx) 716 mod->csumfunc.crc8 = cgw_csum_crc8_pos; 717 else 718 mod->csumfunc.crc8 = cgw_csum_crc8_neg; 719 } 720 721 if (tb[CGW_CS_XOR]) { 722 struct cgw_csum_xor *c = nla_data(tb[CGW_CS_XOR]); 723 724 err = cgw_chk_csum_parms(c->from_idx, c->to_idx, 725 c->result_idx); 726 if (err) 727 return err; 728 729 nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR], 730 CGW_CS_XOR_LEN); 731 732 /* 733 * select dedicated processing function to reduce 734 * runtime operations in receive hot path. 735 */ 736 if (c->from_idx < 0 || c->to_idx < 0 || 737 c->result_idx < 0) 738 mod->csumfunc.xor = cgw_csum_xor_rel; 739 else if (c->from_idx <= c->to_idx) 740 mod->csumfunc.xor = cgw_csum_xor_pos; 741 else 742 mod->csumfunc.xor = cgw_csum_xor_neg; 743 } 744 } 745 746 if (gwtype == CGW_TYPE_CAN_CAN) { 747 748 /* check CGW_TYPE_CAN_CAN specific attributes */ 749 750 struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr; 751 memset(ccgw, 0, sizeof(*ccgw)); 752 753 /* check for can_filter in attributes */ 754 if (tb[CGW_FILTER]) 755 nla_memcpy(&ccgw->filter, tb[CGW_FILTER], 756 sizeof(struct can_filter)); 757 758 err = -ENODEV; 759 760 /* specifying two interfaces is mandatory */ 761 if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF]) 762 return err; 763 764 ccgw->src_idx = nla_get_u32(tb[CGW_SRC_IF]); 765 ccgw->dst_idx = nla_get_u32(tb[CGW_DST_IF]); 766 767 /* both indices set to 0 for flushing all routing entries */ 768 if (!ccgw->src_idx && !ccgw->dst_idx) 769 return 0; 770 771 /* only one index set to 0 is an error */ 772 if (!ccgw->src_idx || !ccgw->dst_idx) 773 return err; 774 } 775 776 /* add the checks for other gwtypes here */ 777 778 return 0; 779 } 780 781 static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh) 782 { 783 struct rtcanmsg *r; 784 struct cgw_job *gwj; 785 int err = 0; 786 787 if (!capable(CAP_NET_ADMIN)) 788 return -EPERM; 789 790 if (nlmsg_len(nlh) < sizeof(*r)) 791 return -EINVAL; 792 793 r = nlmsg_data(nlh); 794 if (r->can_family != AF_CAN) 795 return -EPFNOSUPPORT; 796 797 /* so far we only support CAN -> CAN routings */ 798 if (r->gwtype != CGW_TYPE_CAN_CAN) 799 return -EINVAL; 800 801 gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL); 802 if (!gwj) 803 return -ENOMEM; 804 805 gwj->handled_frames = 0; 806 gwj->dropped_frames = 0; 807 gwj->deleted_frames = 0; 808 gwj->flags = r->flags; 809 gwj->gwtype = r->gwtype; 810 811 err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw); 812 if (err < 0) 813 goto out; 814 815 err = -ENODEV; 816 817 /* ifindex == 0 is not allowed for job creation */ 818 if (!gwj->ccgw.src_idx || !gwj->ccgw.dst_idx) 819 goto out; 820 821 gwj->src.dev = dev_get_by_index(&init_net, gwj->ccgw.src_idx); 822 823 if (!gwj->src.dev) 824 goto out; 825 826 /* check for CAN netdev not using header_ops - see gw_rcv() */ 827 if (gwj->src.dev->type != ARPHRD_CAN || gwj->src.dev->header_ops) 828 goto put_src_out; 829 830 gwj->dst.dev = dev_get_by_index(&init_net, gwj->ccgw.dst_idx); 831 832 if (!gwj->dst.dev) 833 goto put_src_out; 834 835 /* check for CAN netdev not using header_ops - see gw_rcv() */ 836 if (gwj->dst.dev->type != ARPHRD_CAN || gwj->dst.dev->header_ops) 837 goto put_src_dst_out; 838 839 ASSERT_RTNL(); 840 841 err = cgw_register_filter(gwj); 842 if (!err) 843 hlist_add_head_rcu(&gwj->list, &cgw_list); 844 845 put_src_dst_out: 846 dev_put(gwj->dst.dev); 847 put_src_out: 848 dev_put(gwj->src.dev); 849 out: 850 if (err) 851 kmem_cache_free(cgw_cache, gwj); 852 853 return err; 854 } 855 856 static void cgw_remove_all_jobs(void) 857 { 858 struct cgw_job *gwj = NULL; 859 struct hlist_node *nx; 860 861 ASSERT_RTNL(); 862 863 hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) { 864 hlist_del(&gwj->list); 865 cgw_unregister_filter(gwj); 866 kmem_cache_free(cgw_cache, gwj); 867 } 868 } 869 870 static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh) 871 { 872 struct cgw_job *gwj = NULL; 873 struct hlist_node *nx; 874 struct rtcanmsg *r; 875 struct cf_mod mod; 876 struct can_can_gw ccgw; 877 int err = 0; 878 879 if (!capable(CAP_NET_ADMIN)) 880 return -EPERM; 881 882 if (nlmsg_len(nlh) < sizeof(*r)) 883 return -EINVAL; 884 885 r = nlmsg_data(nlh); 886 if (r->can_family != AF_CAN) 887 return -EPFNOSUPPORT; 888 889 /* so far we only support CAN -> CAN routings */ 890 if (r->gwtype != CGW_TYPE_CAN_CAN) 891 return -EINVAL; 892 893 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw); 894 if (err < 0) 895 return err; 896 897 /* two interface indices both set to 0 => remove all entries */ 898 if (!ccgw.src_idx && !ccgw.dst_idx) { 899 cgw_remove_all_jobs(); 900 return 0; 901 } 902 903 err = -EINVAL; 904 905 ASSERT_RTNL(); 906 907 /* remove only the first matching entry */ 908 hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) { 909 910 if (gwj->flags != r->flags) 911 continue; 912 913 if (memcmp(&gwj->mod, &mod, sizeof(mod))) 914 continue; 915 916 /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */ 917 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw))) 918 continue; 919 920 hlist_del(&gwj->list); 921 cgw_unregister_filter(gwj); 922 kmem_cache_free(cgw_cache, gwj); 923 err = 0; 924 break; 925 } 926 927 return err; 928 } 929 930 static __init int cgw_module_init(void) 931 { 932 /* sanitize given module parameter */ 933 max_hops = clamp_t(unsigned int, max_hops, CGW_MIN_HOPS, CGW_MAX_HOPS); 934 935 pr_info("can: netlink gateway (rev " CAN_GW_VERSION ") max_hops=%d\n", 936 max_hops); 937 938 cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job), 939 0, 0, NULL); 940 941 if (!cgw_cache) 942 return -ENOMEM; 943 944 /* set notifier */ 945 notifier.notifier_call = cgw_notifier; 946 register_netdevice_notifier(¬ifier); 947 948 if (__rtnl_register(PF_CAN, RTM_GETROUTE, NULL, cgw_dump_jobs, NULL)) { 949 unregister_netdevice_notifier(¬ifier); 950 kmem_cache_destroy(cgw_cache); 951 return -ENOBUFS; 952 } 953 954 /* Only the first call to __rtnl_register can fail */ 955 __rtnl_register(PF_CAN, RTM_NEWROUTE, cgw_create_job, NULL, NULL); 956 __rtnl_register(PF_CAN, RTM_DELROUTE, cgw_remove_job, NULL, NULL); 957 958 return 0; 959 } 960 961 static __exit void cgw_module_exit(void) 962 { 963 rtnl_unregister_all(PF_CAN); 964 965 unregister_netdevice_notifier(¬ifier); 966 967 rtnl_lock(); 968 cgw_remove_all_jobs(); 969 rtnl_unlock(); 970 971 rcu_barrier(); /* Wait for completion of call_rcu()'s */ 972 973 kmem_cache_destroy(cgw_cache); 974 } 975 976 module_init(cgw_module_init); 977 module_exit(cgw_module_exit); 978