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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
69static HLIST_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);
1/*
2 * gw.c - CAN frame Gateway/Router/Bridge with netlink interface
3 *
4 * Copyright (c) 2017 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 "20170425"
63#define CAN_GW_NAME "can-gw"
64
65MODULE_DESCRIPTION("PF_CAN netlink gateway");
66MODULE_LICENSE("Dual BSD/GPL");
67MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
68MODULE_ALIAS(CAN_GW_NAME);
69
70#define CGW_MIN_HOPS 1
71#define CGW_MAX_HOPS 6
72#define CGW_DEFAULT_HOPS 1
73
74static unsigned int max_hops __read_mostly = CGW_DEFAULT_HOPS;
75module_param(max_hops, uint, 0444);
76MODULE_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
82static struct notifier_block notifier;
83static struct kmem_cache *cgw_cache __read_mostly;
84
85/* structure that contains the (on-the-fly) CAN frame modifications */
86struct cf_mod {
87 struct {
88 struct can_frame and;
89 struct can_frame or;
90 struct can_frame xor;
91 struct can_frame set;
92 } modframe;
93 struct {
94 u8 and;
95 u8 or;
96 u8 xor;
97 u8 set;
98 } modtype;
99 void (*modfunc[MAX_MODFUNCTIONS])(struct can_frame *cf,
100 struct cf_mod *mod);
101
102 /* CAN frame checksum calculation after CAN frame modifications */
103 struct {
104 struct cgw_csum_xor xor;
105 struct cgw_csum_crc8 crc8;
106 } csum;
107 struct {
108 void (*xor)(struct can_frame *cf, struct cgw_csum_xor *xor);
109 void (*crc8)(struct can_frame *cf, struct cgw_csum_crc8 *crc8);
110 } csumfunc;
111 u32 uid;
112};
113
114
115/*
116 * So far we just support CAN -> CAN routing and frame modifications.
117 *
118 * The internal can_can_gw structure contains data and attributes for
119 * a CAN -> CAN gateway job.
120 */
121struct can_can_gw {
122 struct can_filter filter;
123 int src_idx;
124 int dst_idx;
125};
126
127/* list entry for CAN gateways jobs */
128struct cgw_job {
129 struct hlist_node list;
130 struct rcu_head rcu;
131 u32 handled_frames;
132 u32 dropped_frames;
133 u32 deleted_frames;
134 struct cf_mod mod;
135 union {
136 /* CAN frame data source */
137 struct net_device *dev;
138 } src;
139 union {
140 /* CAN frame data destination */
141 struct net_device *dev;
142 } dst;
143 union {
144 struct can_can_gw ccgw;
145 /* tbc */
146 };
147 u8 gwtype;
148 u8 limit_hops;
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
157MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id)
158MODFUNC(mod_and_dlc, cf->can_dlc &= mod->modframe.and.can_dlc)
159MODFUNC(mod_and_data, *(u64 *)cf->data &= *(u64 *)mod->modframe.and.data)
160MODFUNC(mod_or_id, cf->can_id |= mod->modframe.or.can_id)
161MODFUNC(mod_or_dlc, cf->can_dlc |= mod->modframe.or.can_dlc)
162MODFUNC(mod_or_data, *(u64 *)cf->data |= *(u64 *)mod->modframe.or.data)
163MODFUNC(mod_xor_id, cf->can_id ^= mod->modframe.xor.can_id)
164MODFUNC(mod_xor_dlc, cf->can_dlc ^= mod->modframe.xor.can_dlc)
165MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data)
166MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id)
167MODFUNC(mod_set_dlc, cf->can_dlc = mod->modframe.set.can_dlc)
168MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data)
169
170static 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
183static 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
202static 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
210static 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
232static 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
243static 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
254static 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
293static 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
320static 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 */
348static 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/unused 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
406 /* first processing of this CAN frame -> adjust to private hop limit */
407 if (gwj->limit_hops && cgw_hops(nskb) == 1)
408 cgw_hops(nskb) = max_hops - gwj->limit_hops + 1;
409
410 nskb->dev = gwj->dst.dev;
411
412 /* pointer to modifiable CAN frame */
413 cf = (struct can_frame *)nskb->data;
414
415 /* perform preprocessed modification functions if there are any */
416 while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx])
417 (*gwj->mod.modfunc[modidx++])(cf, &gwj->mod);
418
419 /* check for checksum updates when the CAN frame has been modified */
420 if (modidx) {
421 if (gwj->mod.csumfunc.crc8)
422 (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8);
423
424 if (gwj->mod.csumfunc.xor)
425 (*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor);
426 }
427
428 /* clear the skb timestamp if not configured the other way */
429 if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP))
430 nskb->tstamp = 0;
431
432 /* send to netdevice */
433 if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO))
434 gwj->dropped_frames++;
435 else
436 gwj->handled_frames++;
437}
438
439static inline int cgw_register_filter(struct net *net, struct cgw_job *gwj)
440{
441 return can_rx_register(net, gwj->src.dev, gwj->ccgw.filter.can_id,
442 gwj->ccgw.filter.can_mask, can_can_gw_rcv,
443 gwj, "gw", NULL);
444}
445
446static inline void cgw_unregister_filter(struct net *net, struct cgw_job *gwj)
447{
448 can_rx_unregister(net, gwj->src.dev, gwj->ccgw.filter.can_id,
449 gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj);
450}
451
452static int cgw_notifier(struct notifier_block *nb,
453 unsigned long msg, void *ptr)
454{
455 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
456 struct net *net = dev_net(dev);
457
458 if (dev->type != ARPHRD_CAN)
459 return NOTIFY_DONE;
460
461 if (msg == NETDEV_UNREGISTER) {
462
463 struct cgw_job *gwj = NULL;
464 struct hlist_node *nx;
465
466 ASSERT_RTNL();
467
468 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
469
470 if (gwj->src.dev == dev || gwj->dst.dev == dev) {
471 hlist_del(&gwj->list);
472 cgw_unregister_filter(net, gwj);
473 kmem_cache_free(cgw_cache, gwj);
474 }
475 }
476 }
477
478 return NOTIFY_DONE;
479}
480
481static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type,
482 u32 pid, u32 seq, int flags)
483{
484 struct cgw_frame_mod mb;
485 struct rtcanmsg *rtcan;
486 struct nlmsghdr *nlh;
487
488 nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags);
489 if (!nlh)
490 return -EMSGSIZE;
491
492 rtcan = nlmsg_data(nlh);
493 rtcan->can_family = AF_CAN;
494 rtcan->gwtype = gwj->gwtype;
495 rtcan->flags = gwj->flags;
496
497 /* add statistics if available */
498
499 if (gwj->handled_frames) {
500 if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0)
501 goto cancel;
502 }
503
504 if (gwj->dropped_frames) {
505 if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0)
506 goto cancel;
507 }
508
509 if (gwj->deleted_frames) {
510 if (nla_put_u32(skb, CGW_DELETED, gwj->deleted_frames) < 0)
511 goto cancel;
512 }
513
514 /* check non default settings of attributes */
515
516 if (gwj->limit_hops) {
517 if (nla_put_u8(skb, CGW_LIM_HOPS, gwj->limit_hops) < 0)
518 goto cancel;
519 }
520
521 if (gwj->mod.modtype.and) {
522 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
523 mb.modtype = gwj->mod.modtype.and;
524 if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0)
525 goto cancel;
526 }
527
528 if (gwj->mod.modtype.or) {
529 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
530 mb.modtype = gwj->mod.modtype.or;
531 if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0)
532 goto cancel;
533 }
534
535 if (gwj->mod.modtype.xor) {
536 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
537 mb.modtype = gwj->mod.modtype.xor;
538 if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0)
539 goto cancel;
540 }
541
542 if (gwj->mod.modtype.set) {
543 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
544 mb.modtype = gwj->mod.modtype.set;
545 if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0)
546 goto cancel;
547 }
548
549 if (gwj->mod.uid) {
550 if (nla_put_u32(skb, CGW_MOD_UID, gwj->mod.uid) < 0)
551 goto cancel;
552 }
553
554 if (gwj->mod.csumfunc.crc8) {
555 if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN,
556 &gwj->mod.csum.crc8) < 0)
557 goto cancel;
558 }
559
560 if (gwj->mod.csumfunc.xor) {
561 if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN,
562 &gwj->mod.csum.xor) < 0)
563 goto cancel;
564 }
565
566 if (gwj->gwtype == CGW_TYPE_CAN_CAN) {
567
568 if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) {
569 if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter),
570 &gwj->ccgw.filter) < 0)
571 goto cancel;
572 }
573
574 if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0)
575 goto cancel;
576
577 if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0)
578 goto cancel;
579 }
580
581 nlmsg_end(skb, nlh);
582 return 0;
583
584cancel:
585 nlmsg_cancel(skb, nlh);
586 return -EMSGSIZE;
587}
588
589/* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */
590static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb)
591{
592 struct net *net = sock_net(skb->sk);
593 struct cgw_job *gwj = NULL;
594 int idx = 0;
595 int s_idx = cb->args[0];
596
597 rcu_read_lock();
598 hlist_for_each_entry_rcu(gwj, &net->can.cgw_list, list) {
599 if (idx < s_idx)
600 goto cont;
601
602 if (cgw_put_job(skb, gwj, RTM_NEWROUTE, NETLINK_CB(cb->skb).portid,
603 cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0)
604 break;
605cont:
606 idx++;
607 }
608 rcu_read_unlock();
609
610 cb->args[0] = idx;
611
612 return skb->len;
613}
614
615static const struct nla_policy cgw_policy[CGW_MAX+1] = {
616 [CGW_MOD_AND] = { .len = sizeof(struct cgw_frame_mod) },
617 [CGW_MOD_OR] = { .len = sizeof(struct cgw_frame_mod) },
618 [CGW_MOD_XOR] = { .len = sizeof(struct cgw_frame_mod) },
619 [CGW_MOD_SET] = { .len = sizeof(struct cgw_frame_mod) },
620 [CGW_CS_XOR] = { .len = sizeof(struct cgw_csum_xor) },
621 [CGW_CS_CRC8] = { .len = sizeof(struct cgw_csum_crc8) },
622 [CGW_SRC_IF] = { .type = NLA_U32 },
623 [CGW_DST_IF] = { .type = NLA_U32 },
624 [CGW_FILTER] = { .len = sizeof(struct can_filter) },
625 [CGW_LIM_HOPS] = { .type = NLA_U8 },
626 [CGW_MOD_UID] = { .type = NLA_U32 },
627};
628
629/* check for common and gwtype specific attributes */
630static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
631 u8 gwtype, void *gwtypeattr, u8 *limhops)
632{
633 struct nlattr *tb[CGW_MAX+1];
634 struct cgw_frame_mod mb;
635 int modidx = 0;
636 int err = 0;
637
638 /* initialize modification & checksum data space */
639 memset(mod, 0, sizeof(*mod));
640
641 err = nlmsg_parse(nlh, sizeof(struct rtcanmsg), tb, CGW_MAX,
642 cgw_policy, NULL);
643 if (err < 0)
644 return err;
645
646 if (tb[CGW_LIM_HOPS]) {
647 *limhops = nla_get_u8(tb[CGW_LIM_HOPS]);
648
649 if (*limhops < 1 || *limhops > max_hops)
650 return -EINVAL;
651 }
652
653 /* check for AND/OR/XOR/SET modifications */
654
655 if (tb[CGW_MOD_AND]) {
656 nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN);
657
658 canframecpy(&mod->modframe.and, &mb.cf);
659 mod->modtype.and = mb.modtype;
660
661 if (mb.modtype & CGW_MOD_ID)
662 mod->modfunc[modidx++] = mod_and_id;
663
664 if (mb.modtype & CGW_MOD_DLC)
665 mod->modfunc[modidx++] = mod_and_dlc;
666
667 if (mb.modtype & CGW_MOD_DATA)
668 mod->modfunc[modidx++] = mod_and_data;
669 }
670
671 if (tb[CGW_MOD_OR]) {
672 nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN);
673
674 canframecpy(&mod->modframe.or, &mb.cf);
675 mod->modtype.or = mb.modtype;
676
677 if (mb.modtype & CGW_MOD_ID)
678 mod->modfunc[modidx++] = mod_or_id;
679
680 if (mb.modtype & CGW_MOD_DLC)
681 mod->modfunc[modidx++] = mod_or_dlc;
682
683 if (mb.modtype & CGW_MOD_DATA)
684 mod->modfunc[modidx++] = mod_or_data;
685 }
686
687 if (tb[CGW_MOD_XOR]) {
688 nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN);
689
690 canframecpy(&mod->modframe.xor, &mb.cf);
691 mod->modtype.xor = mb.modtype;
692
693 if (mb.modtype & CGW_MOD_ID)
694 mod->modfunc[modidx++] = mod_xor_id;
695
696 if (mb.modtype & CGW_MOD_DLC)
697 mod->modfunc[modidx++] = mod_xor_dlc;
698
699 if (mb.modtype & CGW_MOD_DATA)
700 mod->modfunc[modidx++] = mod_xor_data;
701 }
702
703 if (tb[CGW_MOD_SET]) {
704 nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN);
705
706 canframecpy(&mod->modframe.set, &mb.cf);
707 mod->modtype.set = mb.modtype;
708
709 if (mb.modtype & CGW_MOD_ID)
710 mod->modfunc[modidx++] = mod_set_id;
711
712 if (mb.modtype & CGW_MOD_DLC)
713 mod->modfunc[modidx++] = mod_set_dlc;
714
715 if (mb.modtype & CGW_MOD_DATA)
716 mod->modfunc[modidx++] = mod_set_data;
717 }
718
719 /* check for checksum operations after CAN frame modifications */
720 if (modidx) {
721
722 if (tb[CGW_CS_CRC8]) {
723 struct cgw_csum_crc8 *c = nla_data(tb[CGW_CS_CRC8]);
724
725 err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
726 c->result_idx);
727 if (err)
728 return err;
729
730 nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8],
731 CGW_CS_CRC8_LEN);
732
733 /*
734 * select dedicated processing function to reduce
735 * runtime operations in receive hot path.
736 */
737 if (c->from_idx < 0 || c->to_idx < 0 ||
738 c->result_idx < 0)
739 mod->csumfunc.crc8 = cgw_csum_crc8_rel;
740 else if (c->from_idx <= c->to_idx)
741 mod->csumfunc.crc8 = cgw_csum_crc8_pos;
742 else
743 mod->csumfunc.crc8 = cgw_csum_crc8_neg;
744 }
745
746 if (tb[CGW_CS_XOR]) {
747 struct cgw_csum_xor *c = nla_data(tb[CGW_CS_XOR]);
748
749 err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
750 c->result_idx);
751 if (err)
752 return err;
753
754 nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR],
755 CGW_CS_XOR_LEN);
756
757 /*
758 * select dedicated processing function to reduce
759 * runtime operations in receive hot path.
760 */
761 if (c->from_idx < 0 || c->to_idx < 0 ||
762 c->result_idx < 0)
763 mod->csumfunc.xor = cgw_csum_xor_rel;
764 else if (c->from_idx <= c->to_idx)
765 mod->csumfunc.xor = cgw_csum_xor_pos;
766 else
767 mod->csumfunc.xor = cgw_csum_xor_neg;
768 }
769
770 if (tb[CGW_MOD_UID]) {
771 nla_memcpy(&mod->uid, tb[CGW_MOD_UID], sizeof(u32));
772 }
773 }
774
775 if (gwtype == CGW_TYPE_CAN_CAN) {
776
777 /* check CGW_TYPE_CAN_CAN specific attributes */
778
779 struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr;
780 memset(ccgw, 0, sizeof(*ccgw));
781
782 /* check for can_filter in attributes */
783 if (tb[CGW_FILTER])
784 nla_memcpy(&ccgw->filter, tb[CGW_FILTER],
785 sizeof(struct can_filter));
786
787 err = -ENODEV;
788
789 /* specifying two interfaces is mandatory */
790 if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF])
791 return err;
792
793 ccgw->src_idx = nla_get_u32(tb[CGW_SRC_IF]);
794 ccgw->dst_idx = nla_get_u32(tb[CGW_DST_IF]);
795
796 /* both indices set to 0 for flushing all routing entries */
797 if (!ccgw->src_idx && !ccgw->dst_idx)
798 return 0;
799
800 /* only one index set to 0 is an error */
801 if (!ccgw->src_idx || !ccgw->dst_idx)
802 return err;
803 }
804
805 /* add the checks for other gwtypes here */
806
807 return 0;
808}
809
810static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh,
811 struct netlink_ext_ack *extack)
812{
813 struct net *net = sock_net(skb->sk);
814 struct rtcanmsg *r;
815 struct cgw_job *gwj;
816 struct cf_mod mod;
817 struct can_can_gw ccgw;
818 u8 limhops = 0;
819 int err = 0;
820
821 if (!netlink_capable(skb, CAP_NET_ADMIN))
822 return -EPERM;
823
824 if (nlmsg_len(nlh) < sizeof(*r))
825 return -EINVAL;
826
827 r = nlmsg_data(nlh);
828 if (r->can_family != AF_CAN)
829 return -EPFNOSUPPORT;
830
831 /* so far we only support CAN -> CAN routings */
832 if (r->gwtype != CGW_TYPE_CAN_CAN)
833 return -EINVAL;
834
835 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
836 if (err < 0)
837 return err;
838
839 if (mod.uid) {
840
841 ASSERT_RTNL();
842
843 /* check for updating an existing job with identical uid */
844 hlist_for_each_entry(gwj, &net->can.cgw_list, list) {
845
846 if (gwj->mod.uid != mod.uid)
847 continue;
848
849 /* interfaces & filters must be identical */
850 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
851 return -EINVAL;
852
853 /* update modifications with disabled softirq & quit */
854 local_bh_disable();
855 memcpy(&gwj->mod, &mod, sizeof(mod));
856 local_bh_enable();
857 return 0;
858 }
859 }
860
861 /* ifindex == 0 is not allowed for job creation */
862 if (!ccgw.src_idx || !ccgw.dst_idx)
863 return -ENODEV;
864
865 gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL);
866 if (!gwj)
867 return -ENOMEM;
868
869 gwj->handled_frames = 0;
870 gwj->dropped_frames = 0;
871 gwj->deleted_frames = 0;
872 gwj->flags = r->flags;
873 gwj->gwtype = r->gwtype;
874 gwj->limit_hops = limhops;
875
876 /* insert already parsed information */
877 memcpy(&gwj->mod, &mod, sizeof(mod));
878 memcpy(&gwj->ccgw, &ccgw, sizeof(ccgw));
879
880 err = -ENODEV;
881
882 gwj->src.dev = __dev_get_by_index(net, gwj->ccgw.src_idx);
883
884 if (!gwj->src.dev)
885 goto out;
886
887 if (gwj->src.dev->type != ARPHRD_CAN)
888 goto out;
889
890 gwj->dst.dev = __dev_get_by_index(net, gwj->ccgw.dst_idx);
891
892 if (!gwj->dst.dev)
893 goto out;
894
895 if (gwj->dst.dev->type != ARPHRD_CAN)
896 goto out;
897
898 ASSERT_RTNL();
899
900 err = cgw_register_filter(net, gwj);
901 if (!err)
902 hlist_add_head_rcu(&gwj->list, &net->can.cgw_list);
903out:
904 if (err)
905 kmem_cache_free(cgw_cache, gwj);
906
907 return err;
908}
909
910static void cgw_remove_all_jobs(struct net *net)
911{
912 struct cgw_job *gwj = NULL;
913 struct hlist_node *nx;
914
915 ASSERT_RTNL();
916
917 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
918 hlist_del(&gwj->list);
919 cgw_unregister_filter(net, gwj);
920 kmem_cache_free(cgw_cache, gwj);
921 }
922}
923
924static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh,
925 struct netlink_ext_ack *extack)
926{
927 struct net *net = sock_net(skb->sk);
928 struct cgw_job *gwj = NULL;
929 struct hlist_node *nx;
930 struct rtcanmsg *r;
931 struct cf_mod mod;
932 struct can_can_gw ccgw;
933 u8 limhops = 0;
934 int err = 0;
935
936 if (!netlink_capable(skb, CAP_NET_ADMIN))
937 return -EPERM;
938
939 if (nlmsg_len(nlh) < sizeof(*r))
940 return -EINVAL;
941
942 r = nlmsg_data(nlh);
943 if (r->can_family != AF_CAN)
944 return -EPFNOSUPPORT;
945
946 /* so far we only support CAN -> CAN routings */
947 if (r->gwtype != CGW_TYPE_CAN_CAN)
948 return -EINVAL;
949
950 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
951 if (err < 0)
952 return err;
953
954 /* two interface indices both set to 0 => remove all entries */
955 if (!ccgw.src_idx && !ccgw.dst_idx) {
956 cgw_remove_all_jobs(net);
957 return 0;
958 }
959
960 err = -EINVAL;
961
962 ASSERT_RTNL();
963
964 /* remove only the first matching entry */
965 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
966
967 if (gwj->flags != r->flags)
968 continue;
969
970 if (gwj->limit_hops != limhops)
971 continue;
972
973 /* we have a match when uid is enabled and identical */
974 if (gwj->mod.uid || mod.uid) {
975 if (gwj->mod.uid != mod.uid)
976 continue;
977 } else {
978 /* no uid => check for identical modifications */
979 if (memcmp(&gwj->mod, &mod, sizeof(mod)))
980 continue;
981 }
982
983 /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */
984 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
985 continue;
986
987 hlist_del(&gwj->list);
988 cgw_unregister_filter(net, gwj);
989 kmem_cache_free(cgw_cache, gwj);
990 err = 0;
991 break;
992 }
993
994 return err;
995}
996
997static int __net_init cangw_pernet_init(struct net *net)
998{
999 INIT_HLIST_HEAD(&net->can.cgw_list);
1000 return 0;
1001}
1002
1003static void __net_exit cangw_pernet_exit(struct net *net)
1004{
1005 rtnl_lock();
1006 cgw_remove_all_jobs(net);
1007 rtnl_unlock();
1008}
1009
1010static struct pernet_operations cangw_pernet_ops = {
1011 .init = cangw_pernet_init,
1012 .exit = cangw_pernet_exit,
1013};
1014
1015static __init int cgw_module_init(void)
1016{
1017 int ret;
1018
1019 /* sanitize given module parameter */
1020 max_hops = clamp_t(unsigned int, max_hops, CGW_MIN_HOPS, CGW_MAX_HOPS);
1021
1022 pr_info("can: netlink gateway (rev " CAN_GW_VERSION ") max_hops=%d\n",
1023 max_hops);
1024
1025 register_pernet_subsys(&cangw_pernet_ops);
1026 cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job),
1027 0, 0, NULL);
1028
1029 if (!cgw_cache)
1030 return -ENOMEM;
1031
1032 /* set notifier */
1033 notifier.notifier_call = cgw_notifier;
1034 register_netdevice_notifier(¬ifier);
1035
1036 ret = rtnl_register_module(THIS_MODULE, PF_CAN, RTM_GETROUTE,
1037 NULL, cgw_dump_jobs, 0);
1038 if (ret) {
1039 unregister_netdevice_notifier(¬ifier);
1040 kmem_cache_destroy(cgw_cache);
1041 return -ENOBUFS;
1042 }
1043
1044 /* Only the first call to rtnl_register_module can fail */
1045 rtnl_register_module(THIS_MODULE, PF_CAN, RTM_NEWROUTE,
1046 cgw_create_job, NULL, 0);
1047 rtnl_register_module(THIS_MODULE, PF_CAN, RTM_DELROUTE,
1048 cgw_remove_job, NULL, 0);
1049
1050 return 0;
1051}
1052
1053static __exit void cgw_module_exit(void)
1054{
1055 rtnl_unregister_all(PF_CAN);
1056
1057 unregister_netdevice_notifier(¬ifier);
1058
1059 unregister_pernet_subsys(&cangw_pernet_ops);
1060 rcu_barrier(); /* Wait for completion of call_rcu()'s */
1061
1062 kmem_cache_destroy(cgw_cache);
1063}
1064
1065module_init(cgw_module_init);
1066module_exit(cgw_module_exit);