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/list.h> 46 #include <linux/spinlock.h> 47 #include <linux/rcupdate.h> 48 #include <linux/rculist.h> 49 #include <linux/net.h> 50 #include <linux/netdevice.h> 51 #include <linux/if_arp.h> 52 #include <linux/skbuff.h> 53 #include <linux/can.h> 54 #include <linux/can/core.h> 55 #include <linux/can/gw.h> 56 #include <net/rtnetlink.h> 57 #include <net/net_namespace.h> 58 #include <net/sock.h> 59 60 #define CAN_GW_VERSION "20101209" 61 static __initconst const char banner[] = 62 KERN_INFO "can: netlink gateway (rev " CAN_GW_VERSION ")\n"; 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"); 68 69 static HLIST_HEAD(cgw_list); 70 static struct notifier_block notifier; 71 72 static struct kmem_cache *cgw_cache __read_mostly; 73 74 /* structure that contains the (on-the-fly) CAN frame modifications */ 75 struct cf_mod { 76 struct { 77 struct can_frame and; 78 struct can_frame or; 79 struct can_frame xor; 80 struct can_frame set; 81 } modframe; 82 struct { 83 u8 and; 84 u8 or; 85 u8 xor; 86 u8 set; 87 } modtype; 88 void (*modfunc[MAX_MODFUNCTIONS])(struct can_frame *cf, 89 struct cf_mod *mod); 90 91 /* CAN frame checksum calculation after CAN frame modifications */ 92 struct { 93 struct cgw_csum_xor xor; 94 struct cgw_csum_crc8 crc8; 95 } csum; 96 struct { 97 void (*xor)(struct can_frame *cf, struct cgw_csum_xor *xor); 98 void (*crc8)(struct can_frame *cf, struct cgw_csum_crc8 *crc8); 99 } csumfunc; 100 }; 101 102 103 /* 104 * So far we just support CAN -> CAN routing and frame modifications. 105 * 106 * The internal can_can_gw structure contains data and attributes for 107 * a CAN -> CAN gateway job. 108 */ 109 struct can_can_gw { 110 struct can_filter filter; 111 int src_idx; 112 int dst_idx; 113 }; 114 115 /* list entry for CAN gateways jobs */ 116 struct cgw_job { 117 struct hlist_node list; 118 struct rcu_head rcu; 119 u32 handled_frames; 120 u32 dropped_frames; 121 struct cf_mod mod; 122 union { 123 /* CAN frame data source */ 124 struct net_device *dev; 125 } src; 126 union { 127 /* CAN frame data destination */ 128 struct net_device *dev; 129 } dst; 130 union { 131 struct can_can_gw ccgw; 132 /* tbc */ 133 }; 134 u8 gwtype; 135 u16 flags; 136 }; 137 138 /* modification functions that are invoked in the hot path in can_can_gw_rcv */ 139 140 #define MODFUNC(func, op) static void func(struct can_frame *cf, \ 141 struct cf_mod *mod) { op ; } 142 143 MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id) 144 MODFUNC(mod_and_dlc, cf->can_dlc &= mod->modframe.and.can_dlc) 145 MODFUNC(mod_and_data, *(u64 *)cf->data &= *(u64 *)mod->modframe.and.data) 146 MODFUNC(mod_or_id, cf->can_id |= mod->modframe.or.can_id) 147 MODFUNC(mod_or_dlc, cf->can_dlc |= mod->modframe.or.can_dlc) 148 MODFUNC(mod_or_data, *(u64 *)cf->data |= *(u64 *)mod->modframe.or.data) 149 MODFUNC(mod_xor_id, cf->can_id ^= mod->modframe.xor.can_id) 150 MODFUNC(mod_xor_dlc, cf->can_dlc ^= mod->modframe.xor.can_dlc) 151 MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data) 152 MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id) 153 MODFUNC(mod_set_dlc, cf->can_dlc = mod->modframe.set.can_dlc) 154 MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data) 155 156 static inline void canframecpy(struct can_frame *dst, struct can_frame *src) 157 { 158 /* 159 * Copy the struct members separately to ensure that no uninitialized 160 * data are copied in the 3 bytes hole of the struct. This is needed 161 * to make easy compares of the data in the struct cf_mod. 162 */ 163 164 dst->can_id = src->can_id; 165 dst->can_dlc = src->can_dlc; 166 *(u64 *)dst->data = *(u64 *)src->data; 167 } 168 169 static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re) 170 { 171 /* 172 * absolute dlc values 0 .. 7 => 0 .. 7, e.g. data [0] 173 * relative to received dlc -1 .. -8 : 174 * e.g. for received dlc = 8 175 * -1 => index = 7 (data[7]) 176 * -3 => index = 5 (data[5]) 177 * -8 => index = 0 (data[0]) 178 */ 179 180 if (fr > -9 && fr < 8 && 181 to > -9 && to < 8 && 182 re > -9 && re < 8) 183 return 0; 184 else 185 return -EINVAL; 186 } 187 188 static inline int calc_idx(int idx, int rx_dlc) 189 { 190 if (idx < 0) 191 return rx_dlc + idx; 192 else 193 return idx; 194 } 195 196 static void cgw_csum_xor_rel(struct can_frame *cf, struct cgw_csum_xor *xor) 197 { 198 int from = calc_idx(xor->from_idx, cf->can_dlc); 199 int to = calc_idx(xor->to_idx, cf->can_dlc); 200 int res = calc_idx(xor->result_idx, cf->can_dlc); 201 u8 val = xor->init_xor_val; 202 int i; 203 204 if (from < 0 || to < 0 || res < 0) 205 return; 206 207 if (from <= to) { 208 for (i = from; i <= to; i++) 209 val ^= cf->data[i]; 210 } else { 211 for (i = from; i >= to; i--) 212 val ^= cf->data[i]; 213 } 214 215 cf->data[res] = val; 216 } 217 218 static void cgw_csum_xor_pos(struct can_frame *cf, struct cgw_csum_xor *xor) 219 { 220 u8 val = xor->init_xor_val; 221 int i; 222 223 for (i = xor->from_idx; i <= xor->to_idx; i++) 224 val ^= cf->data[i]; 225 226 cf->data[xor->result_idx] = val; 227 } 228 229 static void cgw_csum_xor_neg(struct can_frame *cf, struct cgw_csum_xor *xor) 230 { 231 u8 val = xor->init_xor_val; 232 int i; 233 234 for (i = xor->from_idx; i >= xor->to_idx; i--) 235 val ^= cf->data[i]; 236 237 cf->data[xor->result_idx] = val; 238 } 239 240 static void cgw_csum_crc8_rel(struct can_frame *cf, struct cgw_csum_crc8 *crc8) 241 { 242 int from = calc_idx(crc8->from_idx, cf->can_dlc); 243 int to = calc_idx(crc8->to_idx, cf->can_dlc); 244 int res = calc_idx(crc8->result_idx, cf->can_dlc); 245 u8 crc = crc8->init_crc_val; 246 int i; 247 248 if (from < 0 || to < 0 || res < 0) 249 return; 250 251 if (from <= to) { 252 for (i = crc8->from_idx; i <= crc8->to_idx; i++) 253 crc = crc8->crctab[crc^cf->data[i]]; 254 } else { 255 for (i = crc8->from_idx; i >= crc8->to_idx; i--) 256 crc = crc8->crctab[crc^cf->data[i]]; 257 } 258 259 switch (crc8->profile) { 260 261 case CGW_CRC8PRF_1U8: 262 crc = crc8->crctab[crc^crc8->profile_data[0]]; 263 break; 264 265 case CGW_CRC8PRF_16U8: 266 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]]; 267 break; 268 269 case CGW_CRC8PRF_SFFID_XOR: 270 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^ 271 (cf->can_id >> 8 & 0xFF)]; 272 break; 273 274 } 275 276 cf->data[crc8->result_idx] = crc^crc8->final_xor_val; 277 } 278 279 static void cgw_csum_crc8_pos(struct can_frame *cf, struct cgw_csum_crc8 *crc8) 280 { 281 u8 crc = crc8->init_crc_val; 282 int i; 283 284 for (i = crc8->from_idx; i <= crc8->to_idx; i++) 285 crc = crc8->crctab[crc^cf->data[i]]; 286 287 switch (crc8->profile) { 288 289 case CGW_CRC8PRF_1U8: 290 crc = crc8->crctab[crc^crc8->profile_data[0]]; 291 break; 292 293 case CGW_CRC8PRF_16U8: 294 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]]; 295 break; 296 297 case CGW_CRC8PRF_SFFID_XOR: 298 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^ 299 (cf->can_id >> 8 & 0xFF)]; 300 break; 301 } 302 303 cf->data[crc8->result_idx] = crc^crc8->final_xor_val; 304 } 305 306 static void cgw_csum_crc8_neg(struct can_frame *cf, struct cgw_csum_crc8 *crc8) 307 { 308 u8 crc = crc8->init_crc_val; 309 int i; 310 311 for (i = crc8->from_idx; i >= crc8->to_idx; i--) 312 crc = crc8->crctab[crc^cf->data[i]]; 313 314 switch (crc8->profile) { 315 316 case CGW_CRC8PRF_1U8: 317 crc = crc8->crctab[crc^crc8->profile_data[0]]; 318 break; 319 320 case CGW_CRC8PRF_16U8: 321 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]]; 322 break; 323 324 case CGW_CRC8PRF_SFFID_XOR: 325 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^ 326 (cf->can_id >> 8 & 0xFF)]; 327 break; 328 } 329 330 cf->data[crc8->result_idx] = crc^crc8->final_xor_val; 331 } 332 333 /* the receive & process & send function */ 334 static void can_can_gw_rcv(struct sk_buff *skb, void *data) 335 { 336 struct cgw_job *gwj = (struct cgw_job *)data; 337 struct can_frame *cf; 338 struct sk_buff *nskb; 339 int modidx = 0; 340 341 /* do not handle already routed frames - see comment below */ 342 if (skb_mac_header_was_set(skb)) 343 return; 344 345 if (!(gwj->dst.dev->flags & IFF_UP)) { 346 gwj->dropped_frames++; 347 return; 348 } 349 350 /* 351 * clone the given skb, which has not been done in can_rcv() 352 * 353 * When there is at least one modification function activated, 354 * we need to copy the skb as we want to modify skb->data. 355 */ 356 if (gwj->mod.modfunc[0]) 357 nskb = skb_copy(skb, GFP_ATOMIC); 358 else 359 nskb = skb_clone(skb, GFP_ATOMIC); 360 361 if (!nskb) { 362 gwj->dropped_frames++; 363 return; 364 } 365 366 /* 367 * Mark routed frames by setting some mac header length which is 368 * not relevant for the CAN frames located in the skb->data section. 369 * 370 * As dev->header_ops is not set in CAN netdevices no one is ever 371 * accessing the various header offsets in the CAN skbuffs anyway. 372 * E.g. using the packet socket to read CAN frames is still working. 373 */ 374 skb_set_mac_header(nskb, 8); 375 nskb->dev = gwj->dst.dev; 376 377 /* pointer to modifiable CAN frame */ 378 cf = (struct can_frame *)nskb->data; 379 380 /* perform preprocessed modification functions if there are any */ 381 while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx]) 382 (*gwj->mod.modfunc[modidx++])(cf, &gwj->mod); 383 384 /* check for checksum updates when the CAN frame has been modified */ 385 if (modidx) { 386 if (gwj->mod.csumfunc.crc8) 387 (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8); 388 389 if (gwj->mod.csumfunc.xor) 390 (*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor); 391 } 392 393 /* clear the skb timestamp if not configured the other way */ 394 if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP)) 395 nskb->tstamp.tv64 = 0; 396 397 /* send to netdevice */ 398 if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO)) 399 gwj->dropped_frames++; 400 else 401 gwj->handled_frames++; 402 } 403 404 static inline int cgw_register_filter(struct cgw_job *gwj) 405 { 406 return can_rx_register(gwj->src.dev, gwj->ccgw.filter.can_id, 407 gwj->ccgw.filter.can_mask, can_can_gw_rcv, 408 gwj, "gw"); 409 } 410 411 static inline void cgw_unregister_filter(struct cgw_job *gwj) 412 { 413 can_rx_unregister(gwj->src.dev, gwj->ccgw.filter.can_id, 414 gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj); 415 } 416 417 static int cgw_notifier(struct notifier_block *nb, 418 unsigned long msg, void *data) 419 { 420 struct net_device *dev = (struct net_device *)data; 421 422 if (!net_eq(dev_net(dev), &init_net)) 423 return NOTIFY_DONE; 424 if (dev->type != ARPHRD_CAN) 425 return NOTIFY_DONE; 426 427 if (msg == NETDEV_UNREGISTER) { 428 429 struct cgw_job *gwj = NULL; 430 struct hlist_node *n, *nx; 431 432 ASSERT_RTNL(); 433 434 hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) { 435 436 if (gwj->src.dev == dev || gwj->dst.dev == dev) { 437 hlist_del(&gwj->list); 438 cgw_unregister_filter(gwj); 439 kfree(gwj); 440 } 441 } 442 } 443 444 return NOTIFY_DONE; 445 } 446 447 static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type, 448 u32 pid, u32 seq, int flags) 449 { 450 struct cgw_frame_mod mb; 451 struct rtcanmsg *rtcan; 452 struct nlmsghdr *nlh; 453 454 nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags); 455 if (!nlh) 456 return -EMSGSIZE; 457 458 rtcan = nlmsg_data(nlh); 459 rtcan->can_family = AF_CAN; 460 rtcan->gwtype = gwj->gwtype; 461 rtcan->flags = gwj->flags; 462 463 /* add statistics if available */ 464 465 if (gwj->handled_frames) { 466 if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0) 467 goto cancel; 468 } 469 470 if (gwj->dropped_frames) { 471 if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0) 472 goto cancel; 473 } 474 475 /* check non default settings of attributes */ 476 477 if (gwj->mod.modtype.and) { 478 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf)); 479 mb.modtype = gwj->mod.modtype.and; 480 if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0) 481 goto cancel; 482 } 483 484 if (gwj->mod.modtype.or) { 485 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf)); 486 mb.modtype = gwj->mod.modtype.or; 487 if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0) 488 goto cancel; 489 } 490 491 if (gwj->mod.modtype.xor) { 492 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf)); 493 mb.modtype = gwj->mod.modtype.xor; 494 if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0) 495 goto cancel; 496 } 497 498 if (gwj->mod.modtype.set) { 499 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf)); 500 mb.modtype = gwj->mod.modtype.set; 501 if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0) 502 goto cancel; 503 } 504 505 if (gwj->mod.csumfunc.crc8) { 506 if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN, 507 &gwj->mod.csum.crc8) < 0) 508 goto cancel; 509 } 510 511 if (gwj->mod.csumfunc.xor) { 512 if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN, 513 &gwj->mod.csum.xor) < 0) 514 goto cancel; 515 } 516 517 if (gwj->gwtype == CGW_TYPE_CAN_CAN) { 518 519 if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) { 520 if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter), 521 &gwj->ccgw.filter) < 0) 522 goto cancel; 523 } 524 525 if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0) 526 goto cancel; 527 528 if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0) 529 goto cancel; 530 } 531 532 return nlmsg_end(skb, nlh); 533 534 cancel: 535 nlmsg_cancel(skb, nlh); 536 return -EMSGSIZE; 537 } 538 539 /* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */ 540 static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb) 541 { 542 struct cgw_job *gwj = NULL; 543 struct hlist_node *n; 544 int idx = 0; 545 int s_idx = cb->args[0]; 546 547 rcu_read_lock(); 548 hlist_for_each_entry_rcu(gwj, n, &cgw_list, list) { 549 if (idx < s_idx) 550 goto cont; 551 552 if (cgw_put_job(skb, gwj, RTM_NEWROUTE, NETLINK_CB(cb->skb).portid, 553 cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0) 554 break; 555 cont: 556 idx++; 557 } 558 rcu_read_unlock(); 559 560 cb->args[0] = idx; 561 562 return skb->len; 563 } 564 565 static const struct nla_policy cgw_policy[CGW_MAX+1] = { 566 [CGW_MOD_AND] = { .len = sizeof(struct cgw_frame_mod) }, 567 [CGW_MOD_OR] = { .len = sizeof(struct cgw_frame_mod) }, 568 [CGW_MOD_XOR] = { .len = sizeof(struct cgw_frame_mod) }, 569 [CGW_MOD_SET] = { .len = sizeof(struct cgw_frame_mod) }, 570 [CGW_CS_XOR] = { .len = sizeof(struct cgw_csum_xor) }, 571 [CGW_CS_CRC8] = { .len = sizeof(struct cgw_csum_crc8) }, 572 [CGW_SRC_IF] = { .type = NLA_U32 }, 573 [CGW_DST_IF] = { .type = NLA_U32 }, 574 [CGW_FILTER] = { .len = sizeof(struct can_filter) }, 575 }; 576 577 /* check for common and gwtype specific attributes */ 578 static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod, 579 u8 gwtype, void *gwtypeattr) 580 { 581 struct nlattr *tb[CGW_MAX+1]; 582 struct cgw_frame_mod mb; 583 int modidx = 0; 584 int err = 0; 585 586 /* initialize modification & checksum data space */ 587 memset(mod, 0, sizeof(*mod)); 588 589 err = nlmsg_parse(nlh, sizeof(struct rtcanmsg), tb, CGW_MAX, 590 cgw_policy); 591 if (err < 0) 592 return err; 593 594 /* check for AND/OR/XOR/SET modifications */ 595 596 if (tb[CGW_MOD_AND]) { 597 nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN); 598 599 canframecpy(&mod->modframe.and, &mb.cf); 600 mod->modtype.and = mb.modtype; 601 602 if (mb.modtype & CGW_MOD_ID) 603 mod->modfunc[modidx++] = mod_and_id; 604 605 if (mb.modtype & CGW_MOD_DLC) 606 mod->modfunc[modidx++] = mod_and_dlc; 607 608 if (mb.modtype & CGW_MOD_DATA) 609 mod->modfunc[modidx++] = mod_and_data; 610 } 611 612 if (tb[CGW_MOD_OR]) { 613 nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN); 614 615 canframecpy(&mod->modframe.or, &mb.cf); 616 mod->modtype.or = mb.modtype; 617 618 if (mb.modtype & CGW_MOD_ID) 619 mod->modfunc[modidx++] = mod_or_id; 620 621 if (mb.modtype & CGW_MOD_DLC) 622 mod->modfunc[modidx++] = mod_or_dlc; 623 624 if (mb.modtype & CGW_MOD_DATA) 625 mod->modfunc[modidx++] = mod_or_data; 626 } 627 628 if (tb[CGW_MOD_XOR]) { 629 nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN); 630 631 canframecpy(&mod->modframe.xor, &mb.cf); 632 mod->modtype.xor = mb.modtype; 633 634 if (mb.modtype & CGW_MOD_ID) 635 mod->modfunc[modidx++] = mod_xor_id; 636 637 if (mb.modtype & CGW_MOD_DLC) 638 mod->modfunc[modidx++] = mod_xor_dlc; 639 640 if (mb.modtype & CGW_MOD_DATA) 641 mod->modfunc[modidx++] = mod_xor_data; 642 } 643 644 if (tb[CGW_MOD_SET]) { 645 nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN); 646 647 canframecpy(&mod->modframe.set, &mb.cf); 648 mod->modtype.set = mb.modtype; 649 650 if (mb.modtype & CGW_MOD_ID) 651 mod->modfunc[modidx++] = mod_set_id; 652 653 if (mb.modtype & CGW_MOD_DLC) 654 mod->modfunc[modidx++] = mod_set_dlc; 655 656 if (mb.modtype & CGW_MOD_DATA) 657 mod->modfunc[modidx++] = mod_set_data; 658 } 659 660 /* check for checksum operations after CAN frame modifications */ 661 if (modidx) { 662 663 if (tb[CGW_CS_CRC8]) { 664 struct cgw_csum_crc8 *c = nla_data(tb[CGW_CS_CRC8]); 665 666 err = cgw_chk_csum_parms(c->from_idx, c->to_idx, 667 c->result_idx); 668 if (err) 669 return err; 670 671 nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8], 672 CGW_CS_CRC8_LEN); 673 674 /* 675 * select dedicated processing function to reduce 676 * runtime operations in receive hot path. 677 */ 678 if (c->from_idx < 0 || c->to_idx < 0 || 679 c->result_idx < 0) 680 mod->csumfunc.crc8 = cgw_csum_crc8_rel; 681 else if (c->from_idx <= c->to_idx) 682 mod->csumfunc.crc8 = cgw_csum_crc8_pos; 683 else 684 mod->csumfunc.crc8 = cgw_csum_crc8_neg; 685 } 686 687 if (tb[CGW_CS_XOR]) { 688 struct cgw_csum_xor *c = nla_data(tb[CGW_CS_XOR]); 689 690 err = cgw_chk_csum_parms(c->from_idx, c->to_idx, 691 c->result_idx); 692 if (err) 693 return err; 694 695 nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR], 696 CGW_CS_XOR_LEN); 697 698 /* 699 * select dedicated processing function to reduce 700 * runtime operations in receive hot path. 701 */ 702 if (c->from_idx < 0 || c->to_idx < 0 || 703 c->result_idx < 0) 704 mod->csumfunc.xor = cgw_csum_xor_rel; 705 else if (c->from_idx <= c->to_idx) 706 mod->csumfunc.xor = cgw_csum_xor_pos; 707 else 708 mod->csumfunc.xor = cgw_csum_xor_neg; 709 } 710 } 711 712 if (gwtype == CGW_TYPE_CAN_CAN) { 713 714 /* check CGW_TYPE_CAN_CAN specific attributes */ 715 716 struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr; 717 memset(ccgw, 0, sizeof(*ccgw)); 718 719 /* check for can_filter in attributes */ 720 if (tb[CGW_FILTER]) 721 nla_memcpy(&ccgw->filter, tb[CGW_FILTER], 722 sizeof(struct can_filter)); 723 724 err = -ENODEV; 725 726 /* specifying two interfaces is mandatory */ 727 if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF]) 728 return err; 729 730 ccgw->src_idx = nla_get_u32(tb[CGW_SRC_IF]); 731 ccgw->dst_idx = nla_get_u32(tb[CGW_DST_IF]); 732 733 /* both indices set to 0 for flushing all routing entries */ 734 if (!ccgw->src_idx && !ccgw->dst_idx) 735 return 0; 736 737 /* only one index set to 0 is an error */ 738 if (!ccgw->src_idx || !ccgw->dst_idx) 739 return err; 740 } 741 742 /* add the checks for other gwtypes here */ 743 744 return 0; 745 } 746 747 static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh, 748 void *arg) 749 { 750 struct rtcanmsg *r; 751 struct cgw_job *gwj; 752 int err = 0; 753 754 if (!capable(CAP_NET_ADMIN)) 755 return -EPERM; 756 757 if (nlmsg_len(nlh) < sizeof(*r)) 758 return -EINVAL; 759 760 r = nlmsg_data(nlh); 761 if (r->can_family != AF_CAN) 762 return -EPFNOSUPPORT; 763 764 /* so far we only support CAN -> CAN routings */ 765 if (r->gwtype != CGW_TYPE_CAN_CAN) 766 return -EINVAL; 767 768 gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL); 769 if (!gwj) 770 return -ENOMEM; 771 772 gwj->handled_frames = 0; 773 gwj->dropped_frames = 0; 774 gwj->flags = r->flags; 775 gwj->gwtype = r->gwtype; 776 777 err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw); 778 if (err < 0) 779 goto out; 780 781 err = -ENODEV; 782 783 /* ifindex == 0 is not allowed for job creation */ 784 if (!gwj->ccgw.src_idx || !gwj->ccgw.dst_idx) 785 goto out; 786 787 gwj->src.dev = dev_get_by_index(&init_net, gwj->ccgw.src_idx); 788 789 if (!gwj->src.dev) 790 goto out; 791 792 /* check for CAN netdev not using header_ops - see gw_rcv() */ 793 if (gwj->src.dev->type != ARPHRD_CAN || gwj->src.dev->header_ops) 794 goto put_src_out; 795 796 gwj->dst.dev = dev_get_by_index(&init_net, gwj->ccgw.dst_idx); 797 798 if (!gwj->dst.dev) 799 goto put_src_out; 800 801 /* check for CAN netdev not using header_ops - see gw_rcv() */ 802 if (gwj->dst.dev->type != ARPHRD_CAN || gwj->dst.dev->header_ops) 803 goto put_src_dst_out; 804 805 ASSERT_RTNL(); 806 807 err = cgw_register_filter(gwj); 808 if (!err) 809 hlist_add_head_rcu(&gwj->list, &cgw_list); 810 811 put_src_dst_out: 812 dev_put(gwj->dst.dev); 813 put_src_out: 814 dev_put(gwj->src.dev); 815 out: 816 if (err) 817 kmem_cache_free(cgw_cache, gwj); 818 819 return err; 820 } 821 822 static void cgw_remove_all_jobs(void) 823 { 824 struct cgw_job *gwj = NULL; 825 struct hlist_node *n, *nx; 826 827 ASSERT_RTNL(); 828 829 hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) { 830 hlist_del(&gwj->list); 831 cgw_unregister_filter(gwj); 832 kfree(gwj); 833 } 834 } 835 836 static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg) 837 { 838 struct cgw_job *gwj = NULL; 839 struct hlist_node *n, *nx; 840 struct rtcanmsg *r; 841 struct cf_mod mod; 842 struct can_can_gw ccgw; 843 int err = 0; 844 845 if (!capable(CAP_NET_ADMIN)) 846 return -EPERM; 847 848 if (nlmsg_len(nlh) < sizeof(*r)) 849 return -EINVAL; 850 851 r = nlmsg_data(nlh); 852 if (r->can_family != AF_CAN) 853 return -EPFNOSUPPORT; 854 855 /* so far we only support CAN -> CAN routings */ 856 if (r->gwtype != CGW_TYPE_CAN_CAN) 857 return -EINVAL; 858 859 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw); 860 if (err < 0) 861 return err; 862 863 /* two interface indices both set to 0 => remove all entries */ 864 if (!ccgw.src_idx && !ccgw.dst_idx) { 865 cgw_remove_all_jobs(); 866 return 0; 867 } 868 869 err = -EINVAL; 870 871 ASSERT_RTNL(); 872 873 /* remove only the first matching entry */ 874 hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) { 875 876 if (gwj->flags != r->flags) 877 continue; 878 879 if (memcmp(&gwj->mod, &mod, sizeof(mod))) 880 continue; 881 882 /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */ 883 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw))) 884 continue; 885 886 hlist_del(&gwj->list); 887 cgw_unregister_filter(gwj); 888 kfree(gwj); 889 err = 0; 890 break; 891 } 892 893 return err; 894 } 895 896 static __init int cgw_module_init(void) 897 { 898 printk(banner); 899 900 cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job), 901 0, 0, NULL); 902 903 if (!cgw_cache) 904 return -ENOMEM; 905 906 /* set notifier */ 907 notifier.notifier_call = cgw_notifier; 908 register_netdevice_notifier(¬ifier); 909 910 if (__rtnl_register(PF_CAN, RTM_GETROUTE, NULL, cgw_dump_jobs, NULL)) { 911 unregister_netdevice_notifier(¬ifier); 912 kmem_cache_destroy(cgw_cache); 913 return -ENOBUFS; 914 } 915 916 /* Only the first call to __rtnl_register can fail */ 917 __rtnl_register(PF_CAN, RTM_NEWROUTE, cgw_create_job, NULL, NULL); 918 __rtnl_register(PF_CAN, RTM_DELROUTE, cgw_remove_job, NULL, NULL); 919 920 return 0; 921 } 922 923 static __exit void cgw_module_exit(void) 924 { 925 rtnl_unregister_all(PF_CAN); 926 927 unregister_netdevice_notifier(¬ifier); 928 929 rtnl_lock(); 930 cgw_remove_all_jobs(); 931 rtnl_unlock(); 932 933 rcu_barrier(); /* Wait for completion of call_rcu()'s */ 934 935 kmem_cache_destroy(cgw_cache); 936 } 937 938 module_init(cgw_module_init); 939 module_exit(cgw_module_exit); 940