gw.c revision f861c2b80c45954e1ea04ead24cafcb1806dd536
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" 61static __initdata const char banner[] = 62 KERN_INFO "can: netlink gateway (rev " CAN_GW_VERSION ")\n"; 63 64MODULE_DESCRIPTION("PF_CAN netlink gateway"); 65MODULE_LICENSE("Dual BSD/GPL"); 66MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>"); 67MODULE_ALIAS("can-gw"); 68 69HLIST_HEAD(cgw_list); 70static struct notifier_block notifier; 71 72static struct kmem_cache *cgw_cache __read_mostly; 73 74/* structure that contains the (on-the-fly) CAN frame modifications */ 75struct 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 */ 109struct 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 */ 116struct 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 143MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id) 144MODFUNC(mod_and_dlc, cf->can_dlc &= mod->modframe.and.can_dlc) 145MODFUNC(mod_and_data, *(u64 *)cf->data &= *(u64 *)mod->modframe.and.data) 146MODFUNC(mod_or_id, cf->can_id |= mod->modframe.or.can_id) 147MODFUNC(mod_or_dlc, cf->can_dlc |= mod->modframe.or.can_dlc) 148MODFUNC(mod_or_data, *(u64 *)cf->data |= *(u64 *)mod->modframe.or.data) 149MODFUNC(mod_xor_id, cf->can_id ^= mod->modframe.xor.can_id) 150MODFUNC(mod_xor_dlc, cf->can_dlc ^= mod->modframe.xor.can_dlc) 151MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data) 152MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id) 153MODFUNC(mod_set_dlc, cf->can_dlc = mod->modframe.set.can_dlc) 154MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data) 155 156static 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 169static 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 188static 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 196static 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 218static 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 229static 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 240static 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 279static 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 306static 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 */ 334static 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 404static 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 411static 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 417static 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 447static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj) 448{ 449 struct cgw_frame_mod mb; 450 struct rtcanmsg *rtcan; 451 struct nlmsghdr *nlh = nlmsg_put(skb, 0, 0, 0, sizeof(*rtcan), 0); 452 if (!nlh) 453 return -EMSGSIZE; 454 455 rtcan = nlmsg_data(nlh); 456 rtcan->can_family = AF_CAN; 457 rtcan->gwtype = gwj->gwtype; 458 rtcan->flags = gwj->flags; 459 460 /* add statistics if available */ 461 462 if (gwj->handled_frames) { 463 if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0) 464 goto cancel; 465 else 466 nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(u32)); 467 } 468 469 if (gwj->dropped_frames) { 470 if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0) 471 goto cancel; 472 else 473 nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(u32)); 474 } 475 476 /* check non default settings of attributes */ 477 478 if (gwj->mod.modtype.and) { 479 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf)); 480 mb.modtype = gwj->mod.modtype.and; 481 if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0) 482 goto cancel; 483 else 484 nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(mb)); 485 } 486 487 if (gwj->mod.modtype.or) { 488 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf)); 489 mb.modtype = gwj->mod.modtype.or; 490 if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0) 491 goto cancel; 492 else 493 nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(mb)); 494 } 495 496 if (gwj->mod.modtype.xor) { 497 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf)); 498 mb.modtype = gwj->mod.modtype.xor; 499 if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0) 500 goto cancel; 501 else 502 nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(mb)); 503 } 504 505 if (gwj->mod.modtype.set) { 506 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf)); 507 mb.modtype = gwj->mod.modtype.set; 508 if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0) 509 goto cancel; 510 else 511 nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(mb)); 512 } 513 514 if (gwj->mod.csumfunc.crc8) { 515 if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN, 516 &gwj->mod.csum.crc8) < 0) 517 goto cancel; 518 else 519 nlh->nlmsg_len += NLA_HDRLEN + \ 520 NLA_ALIGN(CGW_CS_CRC8_LEN); 521 } 522 523 if (gwj->mod.csumfunc.xor) { 524 if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN, 525 &gwj->mod.csum.xor) < 0) 526 goto cancel; 527 else 528 nlh->nlmsg_len += NLA_HDRLEN + \ 529 NLA_ALIGN(CGW_CS_XOR_LEN); 530 } 531 532 if (gwj->gwtype == CGW_TYPE_CAN_CAN) { 533 534 if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) { 535 if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter), 536 &gwj->ccgw.filter) < 0) 537 goto cancel; 538 else 539 nlh->nlmsg_len += NLA_HDRLEN + 540 NLA_ALIGN(sizeof(struct can_filter)); 541 } 542 543 if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0) 544 goto cancel; 545 else 546 nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(u32)); 547 548 if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0) 549 goto cancel; 550 else 551 nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(u32)); 552 } 553 554 return skb->len; 555 556cancel: 557 nlmsg_cancel(skb, nlh); 558 return -EMSGSIZE; 559} 560 561/* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */ 562static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb) 563{ 564 struct cgw_job *gwj = NULL; 565 struct hlist_node *n; 566 int idx = 0; 567 int s_idx = cb->args[0]; 568 569 rcu_read_lock(); 570 hlist_for_each_entry_rcu(gwj, n, &cgw_list, list) { 571 if (idx < s_idx) 572 goto cont; 573 574 if (cgw_put_job(skb, gwj) < 0) 575 break; 576cont: 577 idx++; 578 } 579 rcu_read_unlock(); 580 581 cb->args[0] = idx; 582 583 return skb->len; 584} 585 586/* check for common and gwtype specific attributes */ 587static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod, 588 u8 gwtype, void *gwtypeattr) 589{ 590 struct nlattr *tb[CGW_MAX+1]; 591 struct cgw_frame_mod mb; 592 int modidx = 0; 593 int err = 0; 594 595 /* initialize modification & checksum data space */ 596 memset(mod, 0, sizeof(*mod)); 597 598 err = nlmsg_parse(nlh, sizeof(struct rtcanmsg), tb, CGW_MAX, NULL); 599 if (err < 0) 600 return err; 601 602 /* check for AND/OR/XOR/SET modifications */ 603 604 if (tb[CGW_MOD_AND] && 605 nla_len(tb[CGW_MOD_AND]) == CGW_MODATTR_LEN) { 606 nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN); 607 608 canframecpy(&mod->modframe.and, &mb.cf); 609 mod->modtype.and = mb.modtype; 610 611 if (mb.modtype & CGW_MOD_ID) 612 mod->modfunc[modidx++] = mod_and_id; 613 614 if (mb.modtype & CGW_MOD_DLC) 615 mod->modfunc[modidx++] = mod_and_dlc; 616 617 if (mb.modtype & CGW_MOD_DATA) 618 mod->modfunc[modidx++] = mod_and_data; 619 } 620 621 if (tb[CGW_MOD_OR] && 622 nla_len(tb[CGW_MOD_OR]) == CGW_MODATTR_LEN) { 623 nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN); 624 625 canframecpy(&mod->modframe.or, &mb.cf); 626 mod->modtype.or = mb.modtype; 627 628 if (mb.modtype & CGW_MOD_ID) 629 mod->modfunc[modidx++] = mod_or_id; 630 631 if (mb.modtype & CGW_MOD_DLC) 632 mod->modfunc[modidx++] = mod_or_dlc; 633 634 if (mb.modtype & CGW_MOD_DATA) 635 mod->modfunc[modidx++] = mod_or_data; 636 } 637 638 if (tb[CGW_MOD_XOR] && 639 nla_len(tb[CGW_MOD_XOR]) == CGW_MODATTR_LEN) { 640 nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN); 641 642 canframecpy(&mod->modframe.xor, &mb.cf); 643 mod->modtype.xor = mb.modtype; 644 645 if (mb.modtype & CGW_MOD_ID) 646 mod->modfunc[modidx++] = mod_xor_id; 647 648 if (mb.modtype & CGW_MOD_DLC) 649 mod->modfunc[modidx++] = mod_xor_dlc; 650 651 if (mb.modtype & CGW_MOD_DATA) 652 mod->modfunc[modidx++] = mod_xor_data; 653 } 654 655 if (tb[CGW_MOD_SET] && 656 nla_len(tb[CGW_MOD_SET]) == CGW_MODATTR_LEN) { 657 nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN); 658 659 canframecpy(&mod->modframe.set, &mb.cf); 660 mod->modtype.set = mb.modtype; 661 662 if (mb.modtype & CGW_MOD_ID) 663 mod->modfunc[modidx++] = mod_set_id; 664 665 if (mb.modtype & CGW_MOD_DLC) 666 mod->modfunc[modidx++] = mod_set_dlc; 667 668 if (mb.modtype & CGW_MOD_DATA) 669 mod->modfunc[modidx++] = mod_set_data; 670 } 671 672 /* check for checksum operations after CAN frame modifications */ 673 if (modidx) { 674 675 if (tb[CGW_CS_CRC8] && 676 nla_len(tb[CGW_CS_CRC8]) == CGW_CS_CRC8_LEN) { 677 678 struct cgw_csum_crc8 *c = (struct cgw_csum_crc8 *)\ 679 nla_data(tb[CGW_CS_CRC8]); 680 681 err = cgw_chk_csum_parms(c->from_idx, c->to_idx, 682 c->result_idx); 683 if (err) 684 return err; 685 686 nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8], 687 CGW_CS_CRC8_LEN); 688 689 /* 690 * select dedicated processing function to reduce 691 * runtime operations in receive hot path. 692 */ 693 if (c->from_idx < 0 || c->to_idx < 0 || 694 c->result_idx < 0) 695 mod->csumfunc.crc8 = cgw_csum_crc8_rel; 696 else if (c->from_idx <= c->to_idx) 697 mod->csumfunc.crc8 = cgw_csum_crc8_pos; 698 else 699 mod->csumfunc.crc8 = cgw_csum_crc8_neg; 700 } 701 702 if (tb[CGW_CS_XOR] && 703 nla_len(tb[CGW_CS_XOR]) == CGW_CS_XOR_LEN) { 704 705 struct cgw_csum_xor *c = (struct cgw_csum_xor *)\ 706 nla_data(tb[CGW_CS_XOR]); 707 708 err = cgw_chk_csum_parms(c->from_idx, c->to_idx, 709 c->result_idx); 710 if (err) 711 return err; 712 713 nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR], 714 CGW_CS_XOR_LEN); 715 716 /* 717 * select dedicated processing function to reduce 718 * runtime operations in receive hot path. 719 */ 720 if (c->from_idx < 0 || c->to_idx < 0 || 721 c->result_idx < 0) 722 mod->csumfunc.xor = cgw_csum_xor_rel; 723 else if (c->from_idx <= c->to_idx) 724 mod->csumfunc.xor = cgw_csum_xor_pos; 725 else 726 mod->csumfunc.xor = cgw_csum_xor_neg; 727 } 728 } 729 730 if (gwtype == CGW_TYPE_CAN_CAN) { 731 732 /* check CGW_TYPE_CAN_CAN specific attributes */ 733 734 struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr; 735 memset(ccgw, 0, sizeof(*ccgw)); 736 737 /* check for can_filter in attributes */ 738 if (tb[CGW_FILTER] && 739 nla_len(tb[CGW_FILTER]) == sizeof(struct can_filter)) 740 nla_memcpy(&ccgw->filter, tb[CGW_FILTER], 741 sizeof(struct can_filter)); 742 743 err = -ENODEV; 744 745 /* specifying two interfaces is mandatory */ 746 if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF]) 747 return err; 748 749 if (nla_len(tb[CGW_SRC_IF]) == sizeof(u32)) 750 nla_memcpy(&ccgw->src_idx, tb[CGW_SRC_IF], 751 sizeof(u32)); 752 753 if (nla_len(tb[CGW_DST_IF]) == sizeof(u32)) 754 nla_memcpy(&ccgw->dst_idx, tb[CGW_DST_IF], 755 sizeof(u32)); 756 757 /* both indices set to 0 for flushing all routing entries */ 758 if (!ccgw->src_idx && !ccgw->dst_idx) 759 return 0; 760 761 /* only one index set to 0 is an error */ 762 if (!ccgw->src_idx || !ccgw->dst_idx) 763 return err; 764 } 765 766 /* add the checks for other gwtypes here */ 767 768 return 0; 769} 770 771static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh, 772 void *arg) 773{ 774 struct rtcanmsg *r; 775 struct cgw_job *gwj; 776 int err = 0; 777 778 if (nlmsg_len(nlh) < sizeof(*r)) 779 return -EINVAL; 780 781 r = nlmsg_data(nlh); 782 if (r->can_family != AF_CAN) 783 return -EPFNOSUPPORT; 784 785 /* so far we only support CAN -> CAN routings */ 786 if (r->gwtype != CGW_TYPE_CAN_CAN) 787 return -EINVAL; 788 789 gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL); 790 if (!gwj) 791 return -ENOMEM; 792 793 gwj->handled_frames = 0; 794 gwj->dropped_frames = 0; 795 gwj->flags = r->flags; 796 gwj->gwtype = r->gwtype; 797 798 err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw); 799 if (err < 0) 800 goto out; 801 802 err = -ENODEV; 803 804 /* ifindex == 0 is not allowed for job creation */ 805 if (!gwj->ccgw.src_idx || !gwj->ccgw.dst_idx) 806 goto out; 807 808 gwj->src.dev = dev_get_by_index(&init_net, gwj->ccgw.src_idx); 809 810 if (!gwj->src.dev) 811 goto out; 812 813 /* check for CAN netdev not using header_ops - see gw_rcv() */ 814 if (gwj->src.dev->type != ARPHRD_CAN || gwj->src.dev->header_ops) 815 goto put_src_out; 816 817 gwj->dst.dev = dev_get_by_index(&init_net, gwj->ccgw.dst_idx); 818 819 if (!gwj->dst.dev) 820 goto put_src_out; 821 822 /* check for CAN netdev not using header_ops - see gw_rcv() */ 823 if (gwj->dst.dev->type != ARPHRD_CAN || gwj->dst.dev->header_ops) 824 goto put_src_dst_out; 825 826 ASSERT_RTNL(); 827 828 err = cgw_register_filter(gwj); 829 if (!err) 830 hlist_add_head_rcu(&gwj->list, &cgw_list); 831 832put_src_dst_out: 833 dev_put(gwj->dst.dev); 834put_src_out: 835 dev_put(gwj->src.dev); 836out: 837 if (err) 838 kmem_cache_free(cgw_cache, gwj); 839 840 return err; 841} 842 843static void cgw_remove_all_jobs(void) 844{ 845 struct cgw_job *gwj = NULL; 846 struct hlist_node *n, *nx; 847 848 ASSERT_RTNL(); 849 850 hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) { 851 hlist_del(&gwj->list); 852 cgw_unregister_filter(gwj); 853 kfree(gwj); 854 } 855} 856 857static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg) 858{ 859 struct cgw_job *gwj = NULL; 860 struct hlist_node *n, *nx; 861 struct rtcanmsg *r; 862 struct cf_mod mod; 863 struct can_can_gw ccgw; 864 int err = 0; 865 866 if (nlmsg_len(nlh) < sizeof(*r)) 867 return -EINVAL; 868 869 r = nlmsg_data(nlh); 870 if (r->can_family != AF_CAN) 871 return -EPFNOSUPPORT; 872 873 /* so far we only support CAN -> CAN routings */ 874 if (r->gwtype != CGW_TYPE_CAN_CAN) 875 return -EINVAL; 876 877 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw); 878 if (err < 0) 879 return err; 880 881 /* two interface indices both set to 0 => remove all entries */ 882 if (!ccgw.src_idx && !ccgw.dst_idx) { 883 cgw_remove_all_jobs(); 884 return 0; 885 } 886 887 err = -EINVAL; 888 889 ASSERT_RTNL(); 890 891 /* remove only the first matching entry */ 892 hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) { 893 894 if (gwj->flags != r->flags) 895 continue; 896 897 if (memcmp(&gwj->mod, &mod, sizeof(mod))) 898 continue; 899 900 /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */ 901 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw))) 902 continue; 903 904 hlist_del(&gwj->list); 905 cgw_unregister_filter(gwj); 906 kfree(gwj); 907 err = 0; 908 break; 909 } 910 911 return err; 912} 913 914static __init int cgw_module_init(void) 915{ 916 printk(banner); 917 918 cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job), 919 0, 0, NULL); 920 921 if (!cgw_cache) 922 return -ENOMEM; 923 924 /* set notifier */ 925 notifier.notifier_call = cgw_notifier; 926 register_netdevice_notifier(¬ifier); 927 928 if (__rtnl_register(PF_CAN, RTM_GETROUTE, NULL, cgw_dump_jobs, NULL)) { 929 unregister_netdevice_notifier(¬ifier); 930 kmem_cache_destroy(cgw_cache); 931 return -ENOBUFS; 932 } 933 934 /* Only the first call to __rtnl_register can fail */ 935 __rtnl_register(PF_CAN, RTM_NEWROUTE, cgw_create_job, NULL, NULL); 936 __rtnl_register(PF_CAN, RTM_DELROUTE, cgw_remove_job, NULL, NULL); 937 938 return 0; 939} 940 941static __exit void cgw_module_exit(void) 942{ 943 rtnl_unregister_all(PF_CAN); 944 945 unregister_netdevice_notifier(¬ifier); 946 947 rtnl_lock(); 948 cgw_remove_all_jobs(); 949 rtnl_unlock(); 950 951 rcu_barrier(); /* Wait for completion of call_rcu()'s */ 952 953 kmem_cache_destroy(cgw_cache); 954} 955 956module_init(cgw_module_init); 957module_exit(cgw_module_exit); 958