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1// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
2/* gw.c - CAN frame Gateway/Router/Bridge with netlink interface
3 *
4 * Copyright (c) 2019 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_NAME "can-gw"
63
64MODULE_DESCRIPTION("PF_CAN netlink gateway");
65MODULE_LICENSE("Dual BSD/GPL");
66MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
67MODULE_ALIAS(CAN_GW_NAME);
68
69#define CGW_MIN_HOPS 1
70#define CGW_MAX_HOPS 6
71#define CGW_DEFAULT_HOPS 1
72
73static unsigned int max_hops __read_mostly = CGW_DEFAULT_HOPS;
74module_param(max_hops, uint, 0444);
75MODULE_PARM_DESC(max_hops,
76 "maximum " CAN_GW_NAME " routing hops for CAN frames "
77 "(valid values: " __stringify(CGW_MIN_HOPS) "-"
78 __stringify(CGW_MAX_HOPS) " hops, "
79 "default: " __stringify(CGW_DEFAULT_HOPS) ")");
80
81static struct notifier_block notifier;
82static struct kmem_cache *cgw_cache __read_mostly;
83
84/* structure that contains the (on-the-fly) CAN frame modifications */
85struct cf_mod {
86 struct {
87 struct canfd_frame and;
88 struct canfd_frame or;
89 struct canfd_frame xor;
90 struct canfd_frame set;
91 } modframe;
92 struct {
93 u8 and;
94 u8 or;
95 u8 xor;
96 u8 set;
97 } modtype;
98 void (*modfunc[MAX_MODFUNCTIONS])(struct canfd_frame *cf,
99 struct cf_mod *mod);
100
101 /* CAN frame checksum calculation after CAN frame modifications */
102 struct {
103 struct cgw_csum_xor xor;
104 struct cgw_csum_crc8 crc8;
105 } csum;
106 struct {
107 void (*xor)(struct canfd_frame *cf,
108 struct cgw_csum_xor *xor);
109 void (*crc8)(struct canfd_frame *cf,
110 struct cgw_csum_crc8 *crc8);
111 } csumfunc;
112 u32 uid;
113};
114
115/* So far we just support CAN -> CAN routing and frame modifications.
116 *
117 * The internal can_can_gw structure contains data and attributes for
118 * a CAN -> CAN gateway job.
119 */
120struct can_can_gw {
121 struct can_filter filter;
122 int src_idx;
123 int dst_idx;
124};
125
126/* list entry for CAN gateways jobs */
127struct cgw_job {
128 struct hlist_node list;
129 struct rcu_head rcu;
130 u32 handled_frames;
131 u32 dropped_frames;
132 u32 deleted_frames;
133 struct cf_mod mod;
134 union {
135 /* CAN frame data source */
136 struct net_device *dev;
137 } src;
138 union {
139 /* CAN frame data destination */
140 struct net_device *dev;
141 } dst;
142 union {
143 struct can_can_gw ccgw;
144 /* tbc */
145 };
146 u8 gwtype;
147 u8 limit_hops;
148 u16 flags;
149};
150
151/* modification functions that are invoked in the hot path in can_can_gw_rcv */
152
153#define MODFUNC(func, op) static void func(struct canfd_frame *cf, \
154 struct cf_mod *mod) { op ; }
155
156MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id)
157MODFUNC(mod_and_len, cf->len &= mod->modframe.and.len)
158MODFUNC(mod_and_flags, cf->flags &= mod->modframe.and.flags)
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_len, cf->len |= mod->modframe.or.len)
162MODFUNC(mod_or_flags, cf->flags |= mod->modframe.or.flags)
163MODFUNC(mod_or_data, *(u64 *)cf->data |= *(u64 *)mod->modframe.or.data)
164MODFUNC(mod_xor_id, cf->can_id ^= mod->modframe.xor.can_id)
165MODFUNC(mod_xor_len, cf->len ^= mod->modframe.xor.len)
166MODFUNC(mod_xor_flags, cf->flags ^= mod->modframe.xor.flags)
167MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data)
168MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id)
169MODFUNC(mod_set_len, cf->len = mod->modframe.set.len)
170MODFUNC(mod_set_flags, cf->flags = mod->modframe.set.flags)
171MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data)
172
173static void mod_and_fddata(struct canfd_frame *cf, struct cf_mod *mod)
174{
175 int i;
176
177 for (i = 0; i < CANFD_MAX_DLEN; i += 8)
178 *(u64 *)(cf->data + i) &= *(u64 *)(mod->modframe.and.data + i);
179}
180
181static void mod_or_fddata(struct canfd_frame *cf, struct cf_mod *mod)
182{
183 int i;
184
185 for (i = 0; i < CANFD_MAX_DLEN; i += 8)
186 *(u64 *)(cf->data + i) |= *(u64 *)(mod->modframe.or.data + i);
187}
188
189static void mod_xor_fddata(struct canfd_frame *cf, struct cf_mod *mod)
190{
191 int i;
192
193 for (i = 0; i < CANFD_MAX_DLEN; i += 8)
194 *(u64 *)(cf->data + i) ^= *(u64 *)(mod->modframe.xor.data + i);
195}
196
197static void mod_set_fddata(struct canfd_frame *cf, struct cf_mod *mod)
198{
199 memcpy(cf->data, mod->modframe.set.data, CANFD_MAX_DLEN);
200}
201
202/* retrieve valid CC DLC value and store it into 'len' */
203static void mod_retrieve_ccdlc(struct canfd_frame *cf)
204{
205 struct can_frame *ccf = (struct can_frame *)cf;
206
207 /* len8_dlc is only valid if len == CAN_MAX_DLEN */
208 if (ccf->len != CAN_MAX_DLEN)
209 return;
210
211 /* do we have a valid len8_dlc value from 9 .. 15 ? */
212 if (ccf->len8_dlc > CAN_MAX_DLEN && ccf->len8_dlc <= CAN_MAX_RAW_DLC)
213 ccf->len = ccf->len8_dlc;
214}
215
216/* convert valid CC DLC value in 'len' into struct can_frame elements */
217static void mod_store_ccdlc(struct canfd_frame *cf)
218{
219 struct can_frame *ccf = (struct can_frame *)cf;
220
221 /* clear potential leftovers */
222 ccf->len8_dlc = 0;
223
224 /* plain data length 0 .. 8 - that was easy */
225 if (ccf->len <= CAN_MAX_DLEN)
226 return;
227
228 /* potentially broken values are caught in can_can_gw_rcv() */
229 if (ccf->len > CAN_MAX_RAW_DLC)
230 return;
231
232 /* we have a valid dlc value from 9 .. 15 in ccf->len */
233 ccf->len8_dlc = ccf->len;
234 ccf->len = CAN_MAX_DLEN;
235}
236
237static void mod_and_ccdlc(struct canfd_frame *cf, struct cf_mod *mod)
238{
239 mod_retrieve_ccdlc(cf);
240 mod_and_len(cf, mod);
241 mod_store_ccdlc(cf);
242}
243
244static void mod_or_ccdlc(struct canfd_frame *cf, struct cf_mod *mod)
245{
246 mod_retrieve_ccdlc(cf);
247 mod_or_len(cf, mod);
248 mod_store_ccdlc(cf);
249}
250
251static void mod_xor_ccdlc(struct canfd_frame *cf, struct cf_mod *mod)
252{
253 mod_retrieve_ccdlc(cf);
254 mod_xor_len(cf, mod);
255 mod_store_ccdlc(cf);
256}
257
258static void mod_set_ccdlc(struct canfd_frame *cf, struct cf_mod *mod)
259{
260 mod_set_len(cf, mod);
261 mod_store_ccdlc(cf);
262}
263
264static void canframecpy(struct canfd_frame *dst, struct can_frame *src)
265{
266 /* Copy the struct members separately to ensure that no uninitialized
267 * data are copied in the 3 bytes hole of the struct. This is needed
268 * to make easy compares of the data in the struct cf_mod.
269 */
270
271 dst->can_id = src->can_id;
272 dst->len = src->len;
273 *(u64 *)dst->data = *(u64 *)src->data;
274}
275
276static void canfdframecpy(struct canfd_frame *dst, struct canfd_frame *src)
277{
278 /* Copy the struct members separately to ensure that no uninitialized
279 * data are copied in the 2 bytes hole of the struct. This is needed
280 * to make easy compares of the data in the struct cf_mod.
281 */
282
283 dst->can_id = src->can_id;
284 dst->flags = src->flags;
285 dst->len = src->len;
286 memcpy(dst->data, src->data, CANFD_MAX_DLEN);
287}
288
289static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re, struct rtcanmsg *r)
290{
291 s8 dlen = CAN_MAX_DLEN;
292
293 if (r->flags & CGW_FLAGS_CAN_FD)
294 dlen = CANFD_MAX_DLEN;
295
296 /* absolute dlc values 0 .. 7 => 0 .. 7, e.g. data [0]
297 * relative to received dlc -1 .. -8 :
298 * e.g. for received dlc = 8
299 * -1 => index = 7 (data[7])
300 * -3 => index = 5 (data[5])
301 * -8 => index = 0 (data[0])
302 */
303
304 if (fr >= -dlen && fr < dlen &&
305 to >= -dlen && to < dlen &&
306 re >= -dlen && re < dlen)
307 return 0;
308 else
309 return -EINVAL;
310}
311
312static inline int calc_idx(int idx, int rx_len)
313{
314 if (idx < 0)
315 return rx_len + idx;
316 else
317 return idx;
318}
319
320static void cgw_csum_xor_rel(struct canfd_frame *cf, struct cgw_csum_xor *xor)
321{
322 int from = calc_idx(xor->from_idx, cf->len);
323 int to = calc_idx(xor->to_idx, cf->len);
324 int res = calc_idx(xor->result_idx, cf->len);
325 u8 val = xor->init_xor_val;
326 int i;
327
328 if (from < 0 || to < 0 || res < 0)
329 return;
330
331 if (from <= to) {
332 for (i = from; i <= to; i++)
333 val ^= cf->data[i];
334 } else {
335 for (i = from; i >= to; i--)
336 val ^= cf->data[i];
337 }
338
339 cf->data[res] = val;
340}
341
342static void cgw_csum_xor_pos(struct canfd_frame *cf, struct cgw_csum_xor *xor)
343{
344 u8 val = xor->init_xor_val;
345 int i;
346
347 for (i = xor->from_idx; i <= xor->to_idx; i++)
348 val ^= cf->data[i];
349
350 cf->data[xor->result_idx] = val;
351}
352
353static void cgw_csum_xor_neg(struct canfd_frame *cf, struct cgw_csum_xor *xor)
354{
355 u8 val = xor->init_xor_val;
356 int i;
357
358 for (i = xor->from_idx; i >= xor->to_idx; i--)
359 val ^= cf->data[i];
360
361 cf->data[xor->result_idx] = val;
362}
363
364static void cgw_csum_crc8_rel(struct canfd_frame *cf,
365 struct cgw_csum_crc8 *crc8)
366{
367 int from = calc_idx(crc8->from_idx, cf->len);
368 int to = calc_idx(crc8->to_idx, cf->len);
369 int res = calc_idx(crc8->result_idx, cf->len);
370 u8 crc = crc8->init_crc_val;
371 int i;
372
373 if (from < 0 || to < 0 || res < 0)
374 return;
375
376 if (from <= to) {
377 for (i = crc8->from_idx; i <= crc8->to_idx; i++)
378 crc = crc8->crctab[crc ^ cf->data[i]];
379 } else {
380 for (i = crc8->from_idx; i >= crc8->to_idx; i--)
381 crc = crc8->crctab[crc ^ cf->data[i]];
382 }
383
384 switch (crc8->profile) {
385 case CGW_CRC8PRF_1U8:
386 crc = crc8->crctab[crc ^ crc8->profile_data[0]];
387 break;
388
389 case CGW_CRC8PRF_16U8:
390 crc = crc8->crctab[crc ^ crc8->profile_data[cf->data[1] & 0xF]];
391 break;
392
393 case CGW_CRC8PRF_SFFID_XOR:
394 crc = crc8->crctab[crc ^ (cf->can_id & 0xFF) ^
395 (cf->can_id >> 8 & 0xFF)];
396 break;
397 }
398
399 cf->data[crc8->result_idx] = crc ^ crc8->final_xor_val;
400}
401
402static void cgw_csum_crc8_pos(struct canfd_frame *cf,
403 struct cgw_csum_crc8 *crc8)
404{
405 u8 crc = crc8->init_crc_val;
406 int i;
407
408 for (i = crc8->from_idx; i <= crc8->to_idx; i++)
409 crc = crc8->crctab[crc ^ cf->data[i]];
410
411 switch (crc8->profile) {
412 case CGW_CRC8PRF_1U8:
413 crc = crc8->crctab[crc ^ crc8->profile_data[0]];
414 break;
415
416 case CGW_CRC8PRF_16U8:
417 crc = crc8->crctab[crc ^ crc8->profile_data[cf->data[1] & 0xF]];
418 break;
419
420 case CGW_CRC8PRF_SFFID_XOR:
421 crc = crc8->crctab[crc ^ (cf->can_id & 0xFF) ^
422 (cf->can_id >> 8 & 0xFF)];
423 break;
424 }
425
426 cf->data[crc8->result_idx] = crc ^ crc8->final_xor_val;
427}
428
429static void cgw_csum_crc8_neg(struct canfd_frame *cf,
430 struct cgw_csum_crc8 *crc8)
431{
432 u8 crc = crc8->init_crc_val;
433 int i;
434
435 for (i = crc8->from_idx; i >= crc8->to_idx; i--)
436 crc = crc8->crctab[crc ^ cf->data[i]];
437
438 switch (crc8->profile) {
439 case CGW_CRC8PRF_1U8:
440 crc = crc8->crctab[crc ^ crc8->profile_data[0]];
441 break;
442
443 case CGW_CRC8PRF_16U8:
444 crc = crc8->crctab[crc ^ crc8->profile_data[cf->data[1] & 0xF]];
445 break;
446
447 case CGW_CRC8PRF_SFFID_XOR:
448 crc = crc8->crctab[crc ^ (cf->can_id & 0xFF) ^
449 (cf->can_id >> 8 & 0xFF)];
450 break;
451 }
452
453 cf->data[crc8->result_idx] = crc ^ crc8->final_xor_val;
454}
455
456/* the receive & process & send function */
457static void can_can_gw_rcv(struct sk_buff *skb, void *data)
458{
459 struct cgw_job *gwj = (struct cgw_job *)data;
460 struct canfd_frame *cf;
461 struct sk_buff *nskb;
462 int modidx = 0;
463
464 /* process strictly Classic CAN or CAN FD frames */
465 if (gwj->flags & CGW_FLAGS_CAN_FD) {
466 if (!can_is_canfd_skb(skb))
467 return;
468 } else {
469 if (!can_is_can_skb(skb))
470 return;
471 }
472
473 /* Do not handle CAN frames routed more than 'max_hops' times.
474 * In general we should never catch this delimiter which is intended
475 * to cover a misconfiguration protection (e.g. circular CAN routes).
476 *
477 * The Controller Area Network controllers only accept CAN frames with
478 * correct CRCs - which are not visible in the controller registers.
479 * According to skbuff.h documentation the csum_start element for IP
480 * checksums is undefined/unused when ip_summed == CHECKSUM_UNNECESSARY.
481 * Only CAN skbs can be processed here which already have this property.
482 */
483
484#define cgw_hops(skb) ((skb)->csum_start)
485
486 BUG_ON(skb->ip_summed != CHECKSUM_UNNECESSARY);
487
488 if (cgw_hops(skb) >= max_hops) {
489 /* indicate deleted frames due to misconfiguration */
490 gwj->deleted_frames++;
491 return;
492 }
493
494 if (!(gwj->dst.dev->flags & IFF_UP)) {
495 gwj->dropped_frames++;
496 return;
497 }
498
499 /* is sending the skb back to the incoming interface not allowed? */
500 if (!(gwj->flags & CGW_FLAGS_CAN_IIF_TX_OK) &&
501 can_skb_prv(skb)->ifindex == gwj->dst.dev->ifindex)
502 return;
503
504 /* clone the given skb, which has not been done in can_rcv()
505 *
506 * When there is at least one modification function activated,
507 * we need to copy the skb as we want to modify skb->data.
508 */
509 if (gwj->mod.modfunc[0])
510 nskb = skb_copy(skb, GFP_ATOMIC);
511 else
512 nskb = skb_clone(skb, GFP_ATOMIC);
513
514 if (!nskb) {
515 gwj->dropped_frames++;
516 return;
517 }
518
519 /* put the incremented hop counter in the cloned skb */
520 cgw_hops(nskb) = cgw_hops(skb) + 1;
521
522 /* first processing of this CAN frame -> adjust to private hop limit */
523 if (gwj->limit_hops && cgw_hops(nskb) == 1)
524 cgw_hops(nskb) = max_hops - gwj->limit_hops + 1;
525
526 nskb->dev = gwj->dst.dev;
527
528 /* pointer to modifiable CAN frame */
529 cf = (struct canfd_frame *)nskb->data;
530
531 /* perform preprocessed modification functions if there are any */
532 while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx])
533 (*gwj->mod.modfunc[modidx++])(cf, &gwj->mod);
534
535 /* Has the CAN frame been modified? */
536 if (modidx) {
537 /* get available space for the processed CAN frame type */
538 int max_len = nskb->len - offsetof(struct canfd_frame, data);
539
540 /* dlc may have changed, make sure it fits to the CAN frame */
541 if (cf->len > max_len) {
542 /* delete frame due to misconfiguration */
543 gwj->deleted_frames++;
544 kfree_skb(nskb);
545 return;
546 }
547
548 /* check for checksum updates */
549 if (gwj->mod.csumfunc.crc8)
550 (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8);
551
552 if (gwj->mod.csumfunc.xor)
553 (*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor);
554 }
555
556 /* clear the skb timestamp if not configured the other way */
557 if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP))
558 nskb->tstamp = 0;
559
560 /* send to netdevice */
561 if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO))
562 gwj->dropped_frames++;
563 else
564 gwj->handled_frames++;
565}
566
567static inline int cgw_register_filter(struct net *net, struct cgw_job *gwj)
568{
569 return can_rx_register(net, gwj->src.dev, gwj->ccgw.filter.can_id,
570 gwj->ccgw.filter.can_mask, can_can_gw_rcv,
571 gwj, "gw", NULL);
572}
573
574static inline void cgw_unregister_filter(struct net *net, struct cgw_job *gwj)
575{
576 can_rx_unregister(net, gwj->src.dev, gwj->ccgw.filter.can_id,
577 gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj);
578}
579
580static void cgw_job_free_rcu(struct rcu_head *rcu_head)
581{
582 struct cgw_job *gwj = container_of(rcu_head, struct cgw_job, rcu);
583
584 kmem_cache_free(cgw_cache, gwj);
585}
586
587static int cgw_notifier(struct notifier_block *nb,
588 unsigned long msg, void *ptr)
589{
590 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
591 struct net *net = dev_net(dev);
592
593 if (dev->type != ARPHRD_CAN)
594 return NOTIFY_DONE;
595
596 if (msg == NETDEV_UNREGISTER) {
597 struct cgw_job *gwj = NULL;
598 struct hlist_node *nx;
599
600 ASSERT_RTNL();
601
602 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
603 if (gwj->src.dev == dev || gwj->dst.dev == dev) {
604 hlist_del(&gwj->list);
605 cgw_unregister_filter(net, gwj);
606 call_rcu(&gwj->rcu, cgw_job_free_rcu);
607 }
608 }
609 }
610
611 return NOTIFY_DONE;
612}
613
614static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type,
615 u32 pid, u32 seq, int flags)
616{
617 struct rtcanmsg *rtcan;
618 struct nlmsghdr *nlh;
619
620 nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags);
621 if (!nlh)
622 return -EMSGSIZE;
623
624 rtcan = nlmsg_data(nlh);
625 rtcan->can_family = AF_CAN;
626 rtcan->gwtype = gwj->gwtype;
627 rtcan->flags = gwj->flags;
628
629 /* add statistics if available */
630
631 if (gwj->handled_frames) {
632 if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0)
633 goto cancel;
634 }
635
636 if (gwj->dropped_frames) {
637 if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0)
638 goto cancel;
639 }
640
641 if (gwj->deleted_frames) {
642 if (nla_put_u32(skb, CGW_DELETED, gwj->deleted_frames) < 0)
643 goto cancel;
644 }
645
646 /* check non default settings of attributes */
647
648 if (gwj->limit_hops) {
649 if (nla_put_u8(skb, CGW_LIM_HOPS, gwj->limit_hops) < 0)
650 goto cancel;
651 }
652
653 if (gwj->flags & CGW_FLAGS_CAN_FD) {
654 struct cgw_fdframe_mod mb;
655
656 if (gwj->mod.modtype.and) {
657 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
658 mb.modtype = gwj->mod.modtype.and;
659 if (nla_put(skb, CGW_FDMOD_AND, sizeof(mb), &mb) < 0)
660 goto cancel;
661 }
662
663 if (gwj->mod.modtype.or) {
664 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
665 mb.modtype = gwj->mod.modtype.or;
666 if (nla_put(skb, CGW_FDMOD_OR, sizeof(mb), &mb) < 0)
667 goto cancel;
668 }
669
670 if (gwj->mod.modtype.xor) {
671 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
672 mb.modtype = gwj->mod.modtype.xor;
673 if (nla_put(skb, CGW_FDMOD_XOR, sizeof(mb), &mb) < 0)
674 goto cancel;
675 }
676
677 if (gwj->mod.modtype.set) {
678 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
679 mb.modtype = gwj->mod.modtype.set;
680 if (nla_put(skb, CGW_FDMOD_SET, sizeof(mb), &mb) < 0)
681 goto cancel;
682 }
683 } else {
684 struct cgw_frame_mod mb;
685
686 if (gwj->mod.modtype.and) {
687 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
688 mb.modtype = gwj->mod.modtype.and;
689 if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0)
690 goto cancel;
691 }
692
693 if (gwj->mod.modtype.or) {
694 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
695 mb.modtype = gwj->mod.modtype.or;
696 if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0)
697 goto cancel;
698 }
699
700 if (gwj->mod.modtype.xor) {
701 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
702 mb.modtype = gwj->mod.modtype.xor;
703 if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0)
704 goto cancel;
705 }
706
707 if (gwj->mod.modtype.set) {
708 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
709 mb.modtype = gwj->mod.modtype.set;
710 if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0)
711 goto cancel;
712 }
713 }
714
715 if (gwj->mod.uid) {
716 if (nla_put_u32(skb, CGW_MOD_UID, gwj->mod.uid) < 0)
717 goto cancel;
718 }
719
720 if (gwj->mod.csumfunc.crc8) {
721 if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN,
722 &gwj->mod.csum.crc8) < 0)
723 goto cancel;
724 }
725
726 if (gwj->mod.csumfunc.xor) {
727 if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN,
728 &gwj->mod.csum.xor) < 0)
729 goto cancel;
730 }
731
732 if (gwj->gwtype == CGW_TYPE_CAN_CAN) {
733 if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) {
734 if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter),
735 &gwj->ccgw.filter) < 0)
736 goto cancel;
737 }
738
739 if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0)
740 goto cancel;
741
742 if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0)
743 goto cancel;
744 }
745
746 nlmsg_end(skb, nlh);
747 return 0;
748
749cancel:
750 nlmsg_cancel(skb, nlh);
751 return -EMSGSIZE;
752}
753
754/* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */
755static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb)
756{
757 struct net *net = sock_net(skb->sk);
758 struct cgw_job *gwj = NULL;
759 int idx = 0;
760 int s_idx = cb->args[0];
761
762 rcu_read_lock();
763 hlist_for_each_entry_rcu(gwj, &net->can.cgw_list, list) {
764 if (idx < s_idx)
765 goto cont;
766
767 if (cgw_put_job(skb, gwj, RTM_NEWROUTE,
768 NETLINK_CB(cb->skb).portid,
769 cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0)
770 break;
771cont:
772 idx++;
773 }
774 rcu_read_unlock();
775
776 cb->args[0] = idx;
777
778 return skb->len;
779}
780
781static const struct nla_policy cgw_policy[CGW_MAX + 1] = {
782 [CGW_MOD_AND] = { .len = sizeof(struct cgw_frame_mod) },
783 [CGW_MOD_OR] = { .len = sizeof(struct cgw_frame_mod) },
784 [CGW_MOD_XOR] = { .len = sizeof(struct cgw_frame_mod) },
785 [CGW_MOD_SET] = { .len = sizeof(struct cgw_frame_mod) },
786 [CGW_CS_XOR] = { .len = sizeof(struct cgw_csum_xor) },
787 [CGW_CS_CRC8] = { .len = sizeof(struct cgw_csum_crc8) },
788 [CGW_SRC_IF] = { .type = NLA_U32 },
789 [CGW_DST_IF] = { .type = NLA_U32 },
790 [CGW_FILTER] = { .len = sizeof(struct can_filter) },
791 [CGW_LIM_HOPS] = { .type = NLA_U8 },
792 [CGW_MOD_UID] = { .type = NLA_U32 },
793 [CGW_FDMOD_AND] = { .len = sizeof(struct cgw_fdframe_mod) },
794 [CGW_FDMOD_OR] = { .len = sizeof(struct cgw_fdframe_mod) },
795 [CGW_FDMOD_XOR] = { .len = sizeof(struct cgw_fdframe_mod) },
796 [CGW_FDMOD_SET] = { .len = sizeof(struct cgw_fdframe_mod) },
797};
798
799/* check for common and gwtype specific attributes */
800static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
801 u8 gwtype, void *gwtypeattr, u8 *limhops)
802{
803 struct nlattr *tb[CGW_MAX + 1];
804 struct rtcanmsg *r = nlmsg_data(nlh);
805 int modidx = 0;
806 int err = 0;
807
808 /* initialize modification & checksum data space */
809 memset(mod, 0, sizeof(*mod));
810
811 err = nlmsg_parse_deprecated(nlh, sizeof(struct rtcanmsg), tb,
812 CGW_MAX, cgw_policy, NULL);
813 if (err < 0)
814 return err;
815
816 if (tb[CGW_LIM_HOPS]) {
817 *limhops = nla_get_u8(tb[CGW_LIM_HOPS]);
818
819 if (*limhops < 1 || *limhops > max_hops)
820 return -EINVAL;
821 }
822
823 /* check for AND/OR/XOR/SET modifications */
824 if (r->flags & CGW_FLAGS_CAN_FD) {
825 struct cgw_fdframe_mod mb;
826
827 if (tb[CGW_FDMOD_AND]) {
828 nla_memcpy(&mb, tb[CGW_FDMOD_AND], CGW_FDMODATTR_LEN);
829
830 canfdframecpy(&mod->modframe.and, &mb.cf);
831 mod->modtype.and = mb.modtype;
832
833 if (mb.modtype & CGW_MOD_ID)
834 mod->modfunc[modidx++] = mod_and_id;
835
836 if (mb.modtype & CGW_MOD_LEN)
837 mod->modfunc[modidx++] = mod_and_len;
838
839 if (mb.modtype & CGW_MOD_FLAGS)
840 mod->modfunc[modidx++] = mod_and_flags;
841
842 if (mb.modtype & CGW_MOD_DATA)
843 mod->modfunc[modidx++] = mod_and_fddata;
844 }
845
846 if (tb[CGW_FDMOD_OR]) {
847 nla_memcpy(&mb, tb[CGW_FDMOD_OR], CGW_FDMODATTR_LEN);
848
849 canfdframecpy(&mod->modframe.or, &mb.cf);
850 mod->modtype.or = mb.modtype;
851
852 if (mb.modtype & CGW_MOD_ID)
853 mod->modfunc[modidx++] = mod_or_id;
854
855 if (mb.modtype & CGW_MOD_LEN)
856 mod->modfunc[modidx++] = mod_or_len;
857
858 if (mb.modtype & CGW_MOD_FLAGS)
859 mod->modfunc[modidx++] = mod_or_flags;
860
861 if (mb.modtype & CGW_MOD_DATA)
862 mod->modfunc[modidx++] = mod_or_fddata;
863 }
864
865 if (tb[CGW_FDMOD_XOR]) {
866 nla_memcpy(&mb, tb[CGW_FDMOD_XOR], CGW_FDMODATTR_LEN);
867
868 canfdframecpy(&mod->modframe.xor, &mb.cf);
869 mod->modtype.xor = mb.modtype;
870
871 if (mb.modtype & CGW_MOD_ID)
872 mod->modfunc[modidx++] = mod_xor_id;
873
874 if (mb.modtype & CGW_MOD_LEN)
875 mod->modfunc[modidx++] = mod_xor_len;
876
877 if (mb.modtype & CGW_MOD_FLAGS)
878 mod->modfunc[modidx++] = mod_xor_flags;
879
880 if (mb.modtype & CGW_MOD_DATA)
881 mod->modfunc[modidx++] = mod_xor_fddata;
882 }
883
884 if (tb[CGW_FDMOD_SET]) {
885 nla_memcpy(&mb, tb[CGW_FDMOD_SET], CGW_FDMODATTR_LEN);
886
887 canfdframecpy(&mod->modframe.set, &mb.cf);
888 mod->modtype.set = mb.modtype;
889
890 if (mb.modtype & CGW_MOD_ID)
891 mod->modfunc[modidx++] = mod_set_id;
892
893 if (mb.modtype & CGW_MOD_LEN)
894 mod->modfunc[modidx++] = mod_set_len;
895
896 if (mb.modtype & CGW_MOD_FLAGS)
897 mod->modfunc[modidx++] = mod_set_flags;
898
899 if (mb.modtype & CGW_MOD_DATA)
900 mod->modfunc[modidx++] = mod_set_fddata;
901 }
902 } else {
903 struct cgw_frame_mod mb;
904
905 if (tb[CGW_MOD_AND]) {
906 nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN);
907
908 canframecpy(&mod->modframe.and, &mb.cf);
909 mod->modtype.and = mb.modtype;
910
911 if (mb.modtype & CGW_MOD_ID)
912 mod->modfunc[modidx++] = mod_and_id;
913
914 if (mb.modtype & CGW_MOD_DLC)
915 mod->modfunc[modidx++] = mod_and_ccdlc;
916
917 if (mb.modtype & CGW_MOD_DATA)
918 mod->modfunc[modidx++] = mod_and_data;
919 }
920
921 if (tb[CGW_MOD_OR]) {
922 nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN);
923
924 canframecpy(&mod->modframe.or, &mb.cf);
925 mod->modtype.or = mb.modtype;
926
927 if (mb.modtype & CGW_MOD_ID)
928 mod->modfunc[modidx++] = mod_or_id;
929
930 if (mb.modtype & CGW_MOD_DLC)
931 mod->modfunc[modidx++] = mod_or_ccdlc;
932
933 if (mb.modtype & CGW_MOD_DATA)
934 mod->modfunc[modidx++] = mod_or_data;
935 }
936
937 if (tb[CGW_MOD_XOR]) {
938 nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN);
939
940 canframecpy(&mod->modframe.xor, &mb.cf);
941 mod->modtype.xor = mb.modtype;
942
943 if (mb.modtype & CGW_MOD_ID)
944 mod->modfunc[modidx++] = mod_xor_id;
945
946 if (mb.modtype & CGW_MOD_DLC)
947 mod->modfunc[modidx++] = mod_xor_ccdlc;
948
949 if (mb.modtype & CGW_MOD_DATA)
950 mod->modfunc[modidx++] = mod_xor_data;
951 }
952
953 if (tb[CGW_MOD_SET]) {
954 nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN);
955
956 canframecpy(&mod->modframe.set, &mb.cf);
957 mod->modtype.set = mb.modtype;
958
959 if (mb.modtype & CGW_MOD_ID)
960 mod->modfunc[modidx++] = mod_set_id;
961
962 if (mb.modtype & CGW_MOD_DLC)
963 mod->modfunc[modidx++] = mod_set_ccdlc;
964
965 if (mb.modtype & CGW_MOD_DATA)
966 mod->modfunc[modidx++] = mod_set_data;
967 }
968 }
969
970 /* check for checksum operations after CAN frame modifications */
971 if (modidx) {
972 if (tb[CGW_CS_CRC8]) {
973 struct cgw_csum_crc8 *c = nla_data(tb[CGW_CS_CRC8]);
974
975 err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
976 c->result_idx, r);
977 if (err)
978 return err;
979
980 nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8],
981 CGW_CS_CRC8_LEN);
982
983 /* select dedicated processing function to reduce
984 * runtime operations in receive hot path.
985 */
986 if (c->from_idx < 0 || c->to_idx < 0 ||
987 c->result_idx < 0)
988 mod->csumfunc.crc8 = cgw_csum_crc8_rel;
989 else if (c->from_idx <= c->to_idx)
990 mod->csumfunc.crc8 = cgw_csum_crc8_pos;
991 else
992 mod->csumfunc.crc8 = cgw_csum_crc8_neg;
993 }
994
995 if (tb[CGW_CS_XOR]) {
996 struct cgw_csum_xor *c = nla_data(tb[CGW_CS_XOR]);
997
998 err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
999 c->result_idx, r);
1000 if (err)
1001 return err;
1002
1003 nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR],
1004 CGW_CS_XOR_LEN);
1005
1006 /* select dedicated processing function to reduce
1007 * runtime operations in receive hot path.
1008 */
1009 if (c->from_idx < 0 || c->to_idx < 0 ||
1010 c->result_idx < 0)
1011 mod->csumfunc.xor = cgw_csum_xor_rel;
1012 else if (c->from_idx <= c->to_idx)
1013 mod->csumfunc.xor = cgw_csum_xor_pos;
1014 else
1015 mod->csumfunc.xor = cgw_csum_xor_neg;
1016 }
1017
1018 if (tb[CGW_MOD_UID])
1019 nla_memcpy(&mod->uid, tb[CGW_MOD_UID], sizeof(u32));
1020 }
1021
1022 if (gwtype == CGW_TYPE_CAN_CAN) {
1023 /* check CGW_TYPE_CAN_CAN specific attributes */
1024 struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr;
1025
1026 memset(ccgw, 0, sizeof(*ccgw));
1027
1028 /* check for can_filter in attributes */
1029 if (tb[CGW_FILTER])
1030 nla_memcpy(&ccgw->filter, tb[CGW_FILTER],
1031 sizeof(struct can_filter));
1032
1033 err = -ENODEV;
1034
1035 /* specifying two interfaces is mandatory */
1036 if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF])
1037 return err;
1038
1039 ccgw->src_idx = nla_get_u32(tb[CGW_SRC_IF]);
1040 ccgw->dst_idx = nla_get_u32(tb[CGW_DST_IF]);
1041
1042 /* both indices set to 0 for flushing all routing entries */
1043 if (!ccgw->src_idx && !ccgw->dst_idx)
1044 return 0;
1045
1046 /* only one index set to 0 is an error */
1047 if (!ccgw->src_idx || !ccgw->dst_idx)
1048 return err;
1049 }
1050
1051 /* add the checks for other gwtypes here */
1052
1053 return 0;
1054}
1055
1056static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh,
1057 struct netlink_ext_ack *extack)
1058{
1059 struct net *net = sock_net(skb->sk);
1060 struct rtcanmsg *r;
1061 struct cgw_job *gwj;
1062 struct cf_mod mod;
1063 struct can_can_gw ccgw;
1064 u8 limhops = 0;
1065 int err = 0;
1066
1067 if (!netlink_capable(skb, CAP_NET_ADMIN))
1068 return -EPERM;
1069
1070 if (nlmsg_len(nlh) < sizeof(*r))
1071 return -EINVAL;
1072
1073 r = nlmsg_data(nlh);
1074 if (r->can_family != AF_CAN)
1075 return -EPFNOSUPPORT;
1076
1077 /* so far we only support CAN -> CAN routings */
1078 if (r->gwtype != CGW_TYPE_CAN_CAN)
1079 return -EINVAL;
1080
1081 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
1082 if (err < 0)
1083 return err;
1084
1085 if (mod.uid) {
1086 ASSERT_RTNL();
1087
1088 /* check for updating an existing job with identical uid */
1089 hlist_for_each_entry(gwj, &net->can.cgw_list, list) {
1090 if (gwj->mod.uid != mod.uid)
1091 continue;
1092
1093 /* interfaces & filters must be identical */
1094 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
1095 return -EINVAL;
1096
1097 /* update modifications with disabled softirq & quit */
1098 local_bh_disable();
1099 memcpy(&gwj->mod, &mod, sizeof(mod));
1100 local_bh_enable();
1101 return 0;
1102 }
1103 }
1104
1105 /* ifindex == 0 is not allowed for job creation */
1106 if (!ccgw.src_idx || !ccgw.dst_idx)
1107 return -ENODEV;
1108
1109 gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL);
1110 if (!gwj)
1111 return -ENOMEM;
1112
1113 gwj->handled_frames = 0;
1114 gwj->dropped_frames = 0;
1115 gwj->deleted_frames = 0;
1116 gwj->flags = r->flags;
1117 gwj->gwtype = r->gwtype;
1118 gwj->limit_hops = limhops;
1119
1120 /* insert already parsed information */
1121 memcpy(&gwj->mod, &mod, sizeof(mod));
1122 memcpy(&gwj->ccgw, &ccgw, sizeof(ccgw));
1123
1124 err = -ENODEV;
1125
1126 gwj->src.dev = __dev_get_by_index(net, gwj->ccgw.src_idx);
1127
1128 if (!gwj->src.dev)
1129 goto out;
1130
1131 if (gwj->src.dev->type != ARPHRD_CAN)
1132 goto out;
1133
1134 gwj->dst.dev = __dev_get_by_index(net, gwj->ccgw.dst_idx);
1135
1136 if (!gwj->dst.dev)
1137 goto out;
1138
1139 if (gwj->dst.dev->type != ARPHRD_CAN)
1140 goto out;
1141
1142 ASSERT_RTNL();
1143
1144 err = cgw_register_filter(net, gwj);
1145 if (!err)
1146 hlist_add_head_rcu(&gwj->list, &net->can.cgw_list);
1147out:
1148 if (err)
1149 kmem_cache_free(cgw_cache, gwj);
1150
1151 return err;
1152}
1153
1154static void cgw_remove_all_jobs(struct net *net)
1155{
1156 struct cgw_job *gwj = NULL;
1157 struct hlist_node *nx;
1158
1159 ASSERT_RTNL();
1160
1161 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
1162 hlist_del(&gwj->list);
1163 cgw_unregister_filter(net, gwj);
1164 call_rcu(&gwj->rcu, cgw_job_free_rcu);
1165 }
1166}
1167
1168static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh,
1169 struct netlink_ext_ack *extack)
1170{
1171 struct net *net = sock_net(skb->sk);
1172 struct cgw_job *gwj = NULL;
1173 struct hlist_node *nx;
1174 struct rtcanmsg *r;
1175 struct cf_mod mod;
1176 struct can_can_gw ccgw;
1177 u8 limhops = 0;
1178 int err = 0;
1179
1180 if (!netlink_capable(skb, CAP_NET_ADMIN))
1181 return -EPERM;
1182
1183 if (nlmsg_len(nlh) < sizeof(*r))
1184 return -EINVAL;
1185
1186 r = nlmsg_data(nlh);
1187 if (r->can_family != AF_CAN)
1188 return -EPFNOSUPPORT;
1189
1190 /* so far we only support CAN -> CAN routings */
1191 if (r->gwtype != CGW_TYPE_CAN_CAN)
1192 return -EINVAL;
1193
1194 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
1195 if (err < 0)
1196 return err;
1197
1198 /* two interface indices both set to 0 => remove all entries */
1199 if (!ccgw.src_idx && !ccgw.dst_idx) {
1200 cgw_remove_all_jobs(net);
1201 return 0;
1202 }
1203
1204 err = -EINVAL;
1205
1206 ASSERT_RTNL();
1207
1208 /* remove only the first matching entry */
1209 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
1210 if (gwj->flags != r->flags)
1211 continue;
1212
1213 if (gwj->limit_hops != limhops)
1214 continue;
1215
1216 /* we have a match when uid is enabled and identical */
1217 if (gwj->mod.uid || mod.uid) {
1218 if (gwj->mod.uid != mod.uid)
1219 continue;
1220 } else {
1221 /* no uid => check for identical modifications */
1222 if (memcmp(&gwj->mod, &mod, sizeof(mod)))
1223 continue;
1224 }
1225
1226 /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */
1227 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
1228 continue;
1229
1230 hlist_del(&gwj->list);
1231 cgw_unregister_filter(net, gwj);
1232 call_rcu(&gwj->rcu, cgw_job_free_rcu);
1233 err = 0;
1234 break;
1235 }
1236
1237 return err;
1238}
1239
1240static int __net_init cangw_pernet_init(struct net *net)
1241{
1242 INIT_HLIST_HEAD(&net->can.cgw_list);
1243 return 0;
1244}
1245
1246static void __net_exit cangw_pernet_exit_batch(struct list_head *net_list)
1247{
1248 struct net *net;
1249
1250 rtnl_lock();
1251 list_for_each_entry(net, net_list, exit_list)
1252 cgw_remove_all_jobs(net);
1253 rtnl_unlock();
1254}
1255
1256static struct pernet_operations cangw_pernet_ops = {
1257 .init = cangw_pernet_init,
1258 .exit_batch = cangw_pernet_exit_batch,
1259};
1260
1261static __init int cgw_module_init(void)
1262{
1263 int ret;
1264
1265 /* sanitize given module parameter */
1266 max_hops = clamp_t(unsigned int, max_hops, CGW_MIN_HOPS, CGW_MAX_HOPS);
1267
1268 pr_info("can: netlink gateway - max_hops=%d\n", max_hops);
1269
1270 ret = register_pernet_subsys(&cangw_pernet_ops);
1271 if (ret)
1272 return ret;
1273
1274 ret = -ENOMEM;
1275 cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job),
1276 0, 0, NULL);
1277 if (!cgw_cache)
1278 goto out_cache_create;
1279
1280 /* set notifier */
1281 notifier.notifier_call = cgw_notifier;
1282 ret = register_netdevice_notifier(¬ifier);
1283 if (ret)
1284 goto out_register_notifier;
1285
1286 ret = rtnl_register_module(THIS_MODULE, PF_CAN, RTM_GETROUTE,
1287 NULL, cgw_dump_jobs, 0);
1288 if (ret)
1289 goto out_rtnl_register1;
1290
1291 ret = rtnl_register_module(THIS_MODULE, PF_CAN, RTM_NEWROUTE,
1292 cgw_create_job, NULL, 0);
1293 if (ret)
1294 goto out_rtnl_register2;
1295 ret = rtnl_register_module(THIS_MODULE, PF_CAN, RTM_DELROUTE,
1296 cgw_remove_job, NULL, 0);
1297 if (ret)
1298 goto out_rtnl_register3;
1299
1300 return 0;
1301
1302out_rtnl_register3:
1303 rtnl_unregister(PF_CAN, RTM_NEWROUTE);
1304out_rtnl_register2:
1305 rtnl_unregister(PF_CAN, RTM_GETROUTE);
1306out_rtnl_register1:
1307 unregister_netdevice_notifier(¬ifier);
1308out_register_notifier:
1309 kmem_cache_destroy(cgw_cache);
1310out_cache_create:
1311 unregister_pernet_subsys(&cangw_pernet_ops);
1312
1313 return ret;
1314}
1315
1316static __exit void cgw_module_exit(void)
1317{
1318 rtnl_unregister_all(PF_CAN);
1319
1320 unregister_netdevice_notifier(¬ifier);
1321
1322 unregister_pernet_subsys(&cangw_pernet_ops);
1323 rcu_barrier(); /* Wait for completion of call_rcu()'s */
1324
1325 kmem_cache_destroy(cgw_cache);
1326}
1327
1328module_init(cgw_module_init);
1329module_exit(cgw_module_exit);
1/*
2 * gw.c - CAN frame Gateway/Router/Bridge with netlink interface
3 *
4 * Copyright (c) 2011 Volkswagen Group Electronic Research
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of Volkswagen nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * Alternatively, provided that this notice is retained in full, this
20 * software may be distributed under the terms of the GNU General
21 * Public License ("GPL") version 2, in which case the provisions of the
22 * GPL apply INSTEAD OF those given above.
23 *
24 * The provided data structures and external interfaces from this code
25 * are not restricted to be used by modules with a GPL compatible license.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
30 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
31 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
32 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
33 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
37 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
38 * DAMAGE.
39 *
40 */
41
42#include <linux/module.h>
43#include <linux/init.h>
44#include <linux/types.h>
45#include <linux/kernel.h>
46#include <linux/list.h>
47#include <linux/spinlock.h>
48#include <linux/rcupdate.h>
49#include <linux/rculist.h>
50#include <linux/net.h>
51#include <linux/netdevice.h>
52#include <linux/if_arp.h>
53#include <linux/skbuff.h>
54#include <linux/can.h>
55#include <linux/can/core.h>
56#include <linux/can/skb.h>
57#include <linux/can/gw.h>
58#include <net/rtnetlink.h>
59#include <net/net_namespace.h>
60#include <net/sock.h>
61
62#define CAN_GW_VERSION "20130117"
63#define CAN_GW_NAME "can-gw"
64
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, S_IRUGO);
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 HLIST_HEAD(cgw_list);
83static struct notifier_block notifier;
84
85static struct kmem_cache *cgw_cache __read_mostly;
86
87/* structure that contains the (on-the-fly) CAN frame modifications */
88struct cf_mod {
89 struct {
90 struct can_frame and;
91 struct can_frame or;
92 struct can_frame xor;
93 struct can_frame set;
94 } modframe;
95 struct {
96 u8 and;
97 u8 or;
98 u8 xor;
99 u8 set;
100 } modtype;
101 void (*modfunc[MAX_MODFUNCTIONS])(struct can_frame *cf,
102 struct cf_mod *mod);
103
104 /* CAN frame checksum calculation after CAN frame modifications */
105 struct {
106 struct cgw_csum_xor xor;
107 struct cgw_csum_crc8 crc8;
108 } csum;
109 struct {
110 void (*xor)(struct can_frame *cf, struct cgw_csum_xor *xor);
111 void (*crc8)(struct can_frame *cf, struct cgw_csum_crc8 *crc8);
112 } csumfunc;
113};
114
115
116/*
117 * So far we just support CAN -> CAN routing and frame modifications.
118 *
119 * The internal can_can_gw structure contains data and attributes for
120 * a CAN -> CAN gateway job.
121 */
122struct can_can_gw {
123 struct can_filter filter;
124 int src_idx;
125 int dst_idx;
126};
127
128/* list entry for CAN gateways jobs */
129struct cgw_job {
130 struct hlist_node list;
131 struct rcu_head rcu;
132 u32 handled_frames;
133 u32 dropped_frames;
134 u32 deleted_frames;
135 struct cf_mod mod;
136 union {
137 /* CAN frame data source */
138 struct net_device *dev;
139 } src;
140 union {
141 /* CAN frame data destination */
142 struct net_device *dev;
143 } dst;
144 union {
145 struct can_can_gw ccgw;
146 /* tbc */
147 };
148 u8 gwtype;
149 u8 limit_hops;
150 u16 flags;
151};
152
153/* modification functions that are invoked in the hot path in can_can_gw_rcv */
154
155#define MODFUNC(func, op) static void func(struct can_frame *cf, \
156 struct cf_mod *mod) { op ; }
157
158MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id)
159MODFUNC(mod_and_dlc, cf->can_dlc &= mod->modframe.and.can_dlc)
160MODFUNC(mod_and_data, *(u64 *)cf->data &= *(u64 *)mod->modframe.and.data)
161MODFUNC(mod_or_id, cf->can_id |= mod->modframe.or.can_id)
162MODFUNC(mod_or_dlc, cf->can_dlc |= mod->modframe.or.can_dlc)
163MODFUNC(mod_or_data, *(u64 *)cf->data |= *(u64 *)mod->modframe.or.data)
164MODFUNC(mod_xor_id, cf->can_id ^= mod->modframe.xor.can_id)
165MODFUNC(mod_xor_dlc, cf->can_dlc ^= mod->modframe.xor.can_dlc)
166MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data)
167MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id)
168MODFUNC(mod_set_dlc, cf->can_dlc = mod->modframe.set.can_dlc)
169MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data)
170
171static inline void canframecpy(struct can_frame *dst, struct can_frame *src)
172{
173 /*
174 * Copy the struct members separately to ensure that no uninitialized
175 * data are copied in the 3 bytes hole of the struct. This is needed
176 * to make easy compares of the data in the struct cf_mod.
177 */
178
179 dst->can_id = src->can_id;
180 dst->can_dlc = src->can_dlc;
181 *(u64 *)dst->data = *(u64 *)src->data;
182}
183
184static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re)
185{
186 /*
187 * absolute dlc values 0 .. 7 => 0 .. 7, e.g. data [0]
188 * relative to received dlc -1 .. -8 :
189 * e.g. for received dlc = 8
190 * -1 => index = 7 (data[7])
191 * -3 => index = 5 (data[5])
192 * -8 => index = 0 (data[0])
193 */
194
195 if (fr > -9 && fr < 8 &&
196 to > -9 && to < 8 &&
197 re > -9 && re < 8)
198 return 0;
199 else
200 return -EINVAL;
201}
202
203static inline int calc_idx(int idx, int rx_dlc)
204{
205 if (idx < 0)
206 return rx_dlc + idx;
207 else
208 return idx;
209}
210
211static void cgw_csum_xor_rel(struct can_frame *cf, struct cgw_csum_xor *xor)
212{
213 int from = calc_idx(xor->from_idx, cf->can_dlc);
214 int to = calc_idx(xor->to_idx, cf->can_dlc);
215 int res = calc_idx(xor->result_idx, cf->can_dlc);
216 u8 val = xor->init_xor_val;
217 int i;
218
219 if (from < 0 || to < 0 || res < 0)
220 return;
221
222 if (from <= to) {
223 for (i = from; i <= to; i++)
224 val ^= cf->data[i];
225 } else {
226 for (i = from; i >= to; i--)
227 val ^= cf->data[i];
228 }
229
230 cf->data[res] = val;
231}
232
233static void cgw_csum_xor_pos(struct can_frame *cf, struct cgw_csum_xor *xor)
234{
235 u8 val = xor->init_xor_val;
236 int i;
237
238 for (i = xor->from_idx; i <= xor->to_idx; i++)
239 val ^= cf->data[i];
240
241 cf->data[xor->result_idx] = val;
242}
243
244static void cgw_csum_xor_neg(struct can_frame *cf, struct cgw_csum_xor *xor)
245{
246 u8 val = xor->init_xor_val;
247 int i;
248
249 for (i = xor->from_idx; i >= xor->to_idx; i--)
250 val ^= cf->data[i];
251
252 cf->data[xor->result_idx] = val;
253}
254
255static void cgw_csum_crc8_rel(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
256{
257 int from = calc_idx(crc8->from_idx, cf->can_dlc);
258 int to = calc_idx(crc8->to_idx, cf->can_dlc);
259 int res = calc_idx(crc8->result_idx, cf->can_dlc);
260 u8 crc = crc8->init_crc_val;
261 int i;
262
263 if (from < 0 || to < 0 || res < 0)
264 return;
265
266 if (from <= to) {
267 for (i = crc8->from_idx; i <= crc8->to_idx; i++)
268 crc = crc8->crctab[crc^cf->data[i]];
269 } else {
270 for (i = crc8->from_idx; i >= crc8->to_idx; i--)
271 crc = crc8->crctab[crc^cf->data[i]];
272 }
273
274 switch (crc8->profile) {
275
276 case CGW_CRC8PRF_1U8:
277 crc = crc8->crctab[crc^crc8->profile_data[0]];
278 break;
279
280 case CGW_CRC8PRF_16U8:
281 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
282 break;
283
284 case CGW_CRC8PRF_SFFID_XOR:
285 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
286 (cf->can_id >> 8 & 0xFF)];
287 break;
288
289 }
290
291 cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
292}
293
294static void cgw_csum_crc8_pos(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
295{
296 u8 crc = crc8->init_crc_val;
297 int i;
298
299 for (i = crc8->from_idx; i <= crc8->to_idx; i++)
300 crc = crc8->crctab[crc^cf->data[i]];
301
302 switch (crc8->profile) {
303
304 case CGW_CRC8PRF_1U8:
305 crc = crc8->crctab[crc^crc8->profile_data[0]];
306 break;
307
308 case CGW_CRC8PRF_16U8:
309 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
310 break;
311
312 case CGW_CRC8PRF_SFFID_XOR:
313 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
314 (cf->can_id >> 8 & 0xFF)];
315 break;
316 }
317
318 cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
319}
320
321static void cgw_csum_crc8_neg(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
322{
323 u8 crc = crc8->init_crc_val;
324 int i;
325
326 for (i = crc8->from_idx; i >= crc8->to_idx; i--)
327 crc = crc8->crctab[crc^cf->data[i]];
328
329 switch (crc8->profile) {
330
331 case CGW_CRC8PRF_1U8:
332 crc = crc8->crctab[crc^crc8->profile_data[0]];
333 break;
334
335 case CGW_CRC8PRF_16U8:
336 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
337 break;
338
339 case CGW_CRC8PRF_SFFID_XOR:
340 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
341 (cf->can_id >> 8 & 0xFF)];
342 break;
343 }
344
345 cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
346}
347
348/* the receive & process & send function */
349static void can_can_gw_rcv(struct sk_buff *skb, void *data)
350{
351 struct cgw_job *gwj = (struct cgw_job *)data;
352 struct can_frame *cf;
353 struct sk_buff *nskb;
354 int modidx = 0;
355
356 /*
357 * Do not handle CAN frames routed more than 'max_hops' times.
358 * In general we should never catch this delimiter which is intended
359 * to cover a misconfiguration protection (e.g. circular CAN routes).
360 *
361 * The Controller Area Network controllers only accept CAN frames with
362 * correct CRCs - which are not visible in the controller registers.
363 * According to skbuff.h documentation the csum_start element for IP
364 * checksums is undefined/unsued when ip_summed == CHECKSUM_UNNECESSARY.
365 * Only CAN skbs can be processed here which already have this property.
366 */
367
368#define cgw_hops(skb) ((skb)->csum_start)
369
370 BUG_ON(skb->ip_summed != CHECKSUM_UNNECESSARY);
371
372 if (cgw_hops(skb) >= max_hops) {
373 /* indicate deleted frames due to misconfiguration */
374 gwj->deleted_frames++;
375 return;
376 }
377
378 if (!(gwj->dst.dev->flags & IFF_UP)) {
379 gwj->dropped_frames++;
380 return;
381 }
382
383 /* is sending the skb back to the incoming interface not allowed? */
384 if (!(gwj->flags & CGW_FLAGS_CAN_IIF_TX_OK) &&
385 can_skb_prv(skb)->ifindex == gwj->dst.dev->ifindex)
386 return;
387
388 /*
389 * clone the given skb, which has not been done in can_rcv()
390 *
391 * When there is at least one modification function activated,
392 * we need to copy the skb as we want to modify skb->data.
393 */
394 if (gwj->mod.modfunc[0])
395 nskb = skb_copy(skb, GFP_ATOMIC);
396 else
397 nskb = skb_clone(skb, GFP_ATOMIC);
398
399 if (!nskb) {
400 gwj->dropped_frames++;
401 return;
402 }
403
404 /* put the incremented hop counter in the cloned skb */
405 cgw_hops(nskb) = cgw_hops(skb) + 1;
406
407 /* first processing of this CAN frame -> adjust to private hop limit */
408 if (gwj->limit_hops && cgw_hops(nskb) == 1)
409 cgw_hops(nskb) = max_hops - gwj->limit_hops + 1;
410
411 nskb->dev = gwj->dst.dev;
412
413 /* pointer to modifiable CAN frame */
414 cf = (struct can_frame *)nskb->data;
415
416 /* perform preprocessed modification functions if there are any */
417 while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx])
418 (*gwj->mod.modfunc[modidx++])(cf, &gwj->mod);
419
420 /* check for checksum updates when the CAN frame has been modified */
421 if (modidx) {
422 if (gwj->mod.csumfunc.crc8)
423 (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8);
424
425 if (gwj->mod.csumfunc.xor)
426 (*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor);
427 }
428
429 /* clear the skb timestamp if not configured the other way */
430 if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP))
431 nskb->tstamp.tv64 = 0;
432
433 /* send to netdevice */
434 if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO))
435 gwj->dropped_frames++;
436 else
437 gwj->handled_frames++;
438}
439
440static inline int cgw_register_filter(struct cgw_job *gwj)
441{
442 return can_rx_register(gwj->src.dev, gwj->ccgw.filter.can_id,
443 gwj->ccgw.filter.can_mask, can_can_gw_rcv,
444 gwj, "gw");
445}
446
447static inline void cgw_unregister_filter(struct cgw_job *gwj)
448{
449 can_rx_unregister(gwj->src.dev, gwj->ccgw.filter.can_id,
450 gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj);
451}
452
453static int cgw_notifier(struct notifier_block *nb,
454 unsigned long msg, void *ptr)
455{
456 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
457
458 if (!net_eq(dev_net(dev), &init_net))
459 return NOTIFY_DONE;
460 if (dev->type != ARPHRD_CAN)
461 return NOTIFY_DONE;
462
463 if (msg == NETDEV_UNREGISTER) {
464
465 struct cgw_job *gwj = NULL;
466 struct hlist_node *nx;
467
468 ASSERT_RTNL();
469
470 hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) {
471
472 if (gwj->src.dev == dev || gwj->dst.dev == dev) {
473 hlist_del(&gwj->list);
474 cgw_unregister_filter(gwj);
475 kmem_cache_free(cgw_cache, gwj);
476 }
477 }
478 }
479
480 return NOTIFY_DONE;
481}
482
483static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type,
484 u32 pid, u32 seq, int flags)
485{
486 struct cgw_frame_mod mb;
487 struct rtcanmsg *rtcan;
488 struct nlmsghdr *nlh;
489
490 nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags);
491 if (!nlh)
492 return -EMSGSIZE;
493
494 rtcan = nlmsg_data(nlh);
495 rtcan->can_family = AF_CAN;
496 rtcan->gwtype = gwj->gwtype;
497 rtcan->flags = gwj->flags;
498
499 /* add statistics if available */
500
501 if (gwj->handled_frames) {
502 if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0)
503 goto cancel;
504 }
505
506 if (gwj->dropped_frames) {
507 if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0)
508 goto cancel;
509 }
510
511 if (gwj->deleted_frames) {
512 if (nla_put_u32(skb, CGW_DELETED, gwj->deleted_frames) < 0)
513 goto cancel;
514 }
515
516 /* check non default settings of attributes */
517
518 if (gwj->limit_hops) {
519 if (nla_put_u8(skb, CGW_LIM_HOPS, gwj->limit_hops) < 0)
520 goto cancel;
521 }
522
523 if (gwj->mod.modtype.and) {
524 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
525 mb.modtype = gwj->mod.modtype.and;
526 if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0)
527 goto cancel;
528 }
529
530 if (gwj->mod.modtype.or) {
531 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
532 mb.modtype = gwj->mod.modtype.or;
533 if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0)
534 goto cancel;
535 }
536
537 if (gwj->mod.modtype.xor) {
538 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
539 mb.modtype = gwj->mod.modtype.xor;
540 if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0)
541 goto cancel;
542 }
543
544 if (gwj->mod.modtype.set) {
545 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
546 mb.modtype = gwj->mod.modtype.set;
547 if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0)
548 goto cancel;
549 }
550
551 if (gwj->mod.csumfunc.crc8) {
552 if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN,
553 &gwj->mod.csum.crc8) < 0)
554 goto cancel;
555 }
556
557 if (gwj->mod.csumfunc.xor) {
558 if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN,
559 &gwj->mod.csum.xor) < 0)
560 goto cancel;
561 }
562
563 if (gwj->gwtype == CGW_TYPE_CAN_CAN) {
564
565 if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) {
566 if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter),
567 &gwj->ccgw.filter) < 0)
568 goto cancel;
569 }
570
571 if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0)
572 goto cancel;
573
574 if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0)
575 goto cancel;
576 }
577
578 return nlmsg_end(skb, nlh);
579
580cancel:
581 nlmsg_cancel(skb, nlh);
582 return -EMSGSIZE;
583}
584
585/* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */
586static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb)
587{
588 struct cgw_job *gwj = NULL;
589 int idx = 0;
590 int s_idx = cb->args[0];
591
592 rcu_read_lock();
593 hlist_for_each_entry_rcu(gwj, &cgw_list, list) {
594 if (idx < s_idx)
595 goto cont;
596
597 if (cgw_put_job(skb, gwj, RTM_NEWROUTE, NETLINK_CB(cb->skb).portid,
598 cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0)
599 break;
600cont:
601 idx++;
602 }
603 rcu_read_unlock();
604
605 cb->args[0] = idx;
606
607 return skb->len;
608}
609
610static const struct nla_policy cgw_policy[CGW_MAX+1] = {
611 [CGW_MOD_AND] = { .len = sizeof(struct cgw_frame_mod) },
612 [CGW_MOD_OR] = { .len = sizeof(struct cgw_frame_mod) },
613 [CGW_MOD_XOR] = { .len = sizeof(struct cgw_frame_mod) },
614 [CGW_MOD_SET] = { .len = sizeof(struct cgw_frame_mod) },
615 [CGW_CS_XOR] = { .len = sizeof(struct cgw_csum_xor) },
616 [CGW_CS_CRC8] = { .len = sizeof(struct cgw_csum_crc8) },
617 [CGW_SRC_IF] = { .type = NLA_U32 },
618 [CGW_DST_IF] = { .type = NLA_U32 },
619 [CGW_FILTER] = { .len = sizeof(struct can_filter) },
620 [CGW_LIM_HOPS] = { .type = NLA_U8 },
621};
622
623/* check for common and gwtype specific attributes */
624static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
625 u8 gwtype, void *gwtypeattr, u8 *limhops)
626{
627 struct nlattr *tb[CGW_MAX+1];
628 struct cgw_frame_mod mb;
629 int modidx = 0;
630 int err = 0;
631
632 /* initialize modification & checksum data space */
633 memset(mod, 0, sizeof(*mod));
634
635 err = nlmsg_parse(nlh, sizeof(struct rtcanmsg), tb, CGW_MAX,
636 cgw_policy);
637 if (err < 0)
638 return err;
639
640 if (tb[CGW_LIM_HOPS]) {
641 *limhops = nla_get_u8(tb[CGW_LIM_HOPS]);
642
643 if (*limhops < 1 || *limhops > max_hops)
644 return -EINVAL;
645 }
646
647 /* check for AND/OR/XOR/SET modifications */
648
649 if (tb[CGW_MOD_AND]) {
650 nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN);
651
652 canframecpy(&mod->modframe.and, &mb.cf);
653 mod->modtype.and = mb.modtype;
654
655 if (mb.modtype & CGW_MOD_ID)
656 mod->modfunc[modidx++] = mod_and_id;
657
658 if (mb.modtype & CGW_MOD_DLC)
659 mod->modfunc[modidx++] = mod_and_dlc;
660
661 if (mb.modtype & CGW_MOD_DATA)
662 mod->modfunc[modidx++] = mod_and_data;
663 }
664
665 if (tb[CGW_MOD_OR]) {
666 nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN);
667
668 canframecpy(&mod->modframe.or, &mb.cf);
669 mod->modtype.or = mb.modtype;
670
671 if (mb.modtype & CGW_MOD_ID)
672 mod->modfunc[modidx++] = mod_or_id;
673
674 if (mb.modtype & CGW_MOD_DLC)
675 mod->modfunc[modidx++] = mod_or_dlc;
676
677 if (mb.modtype & CGW_MOD_DATA)
678 mod->modfunc[modidx++] = mod_or_data;
679 }
680
681 if (tb[CGW_MOD_XOR]) {
682 nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN);
683
684 canframecpy(&mod->modframe.xor, &mb.cf);
685 mod->modtype.xor = mb.modtype;
686
687 if (mb.modtype & CGW_MOD_ID)
688 mod->modfunc[modidx++] = mod_xor_id;
689
690 if (mb.modtype & CGW_MOD_DLC)
691 mod->modfunc[modidx++] = mod_xor_dlc;
692
693 if (mb.modtype & CGW_MOD_DATA)
694 mod->modfunc[modidx++] = mod_xor_data;
695 }
696
697 if (tb[CGW_MOD_SET]) {
698 nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN);
699
700 canframecpy(&mod->modframe.set, &mb.cf);
701 mod->modtype.set = mb.modtype;
702
703 if (mb.modtype & CGW_MOD_ID)
704 mod->modfunc[modidx++] = mod_set_id;
705
706 if (mb.modtype & CGW_MOD_DLC)
707 mod->modfunc[modidx++] = mod_set_dlc;
708
709 if (mb.modtype & CGW_MOD_DATA)
710 mod->modfunc[modidx++] = mod_set_data;
711 }
712
713 /* check for checksum operations after CAN frame modifications */
714 if (modidx) {
715
716 if (tb[CGW_CS_CRC8]) {
717 struct cgw_csum_crc8 *c = nla_data(tb[CGW_CS_CRC8]);
718
719 err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
720 c->result_idx);
721 if (err)
722 return err;
723
724 nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8],
725 CGW_CS_CRC8_LEN);
726
727 /*
728 * select dedicated processing function to reduce
729 * runtime operations in receive hot path.
730 */
731 if (c->from_idx < 0 || c->to_idx < 0 ||
732 c->result_idx < 0)
733 mod->csumfunc.crc8 = cgw_csum_crc8_rel;
734 else if (c->from_idx <= c->to_idx)
735 mod->csumfunc.crc8 = cgw_csum_crc8_pos;
736 else
737 mod->csumfunc.crc8 = cgw_csum_crc8_neg;
738 }
739
740 if (tb[CGW_CS_XOR]) {
741 struct cgw_csum_xor *c = nla_data(tb[CGW_CS_XOR]);
742
743 err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
744 c->result_idx);
745 if (err)
746 return err;
747
748 nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR],
749 CGW_CS_XOR_LEN);
750
751 /*
752 * select dedicated processing function to reduce
753 * runtime operations in receive hot path.
754 */
755 if (c->from_idx < 0 || c->to_idx < 0 ||
756 c->result_idx < 0)
757 mod->csumfunc.xor = cgw_csum_xor_rel;
758 else if (c->from_idx <= c->to_idx)
759 mod->csumfunc.xor = cgw_csum_xor_pos;
760 else
761 mod->csumfunc.xor = cgw_csum_xor_neg;
762 }
763 }
764
765 if (gwtype == CGW_TYPE_CAN_CAN) {
766
767 /* check CGW_TYPE_CAN_CAN specific attributes */
768
769 struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr;
770 memset(ccgw, 0, sizeof(*ccgw));
771
772 /* check for can_filter in attributes */
773 if (tb[CGW_FILTER])
774 nla_memcpy(&ccgw->filter, tb[CGW_FILTER],
775 sizeof(struct can_filter));
776
777 err = -ENODEV;
778
779 /* specifying two interfaces is mandatory */
780 if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF])
781 return err;
782
783 ccgw->src_idx = nla_get_u32(tb[CGW_SRC_IF]);
784 ccgw->dst_idx = nla_get_u32(tb[CGW_DST_IF]);
785
786 /* both indices set to 0 for flushing all routing entries */
787 if (!ccgw->src_idx && !ccgw->dst_idx)
788 return 0;
789
790 /* only one index set to 0 is an error */
791 if (!ccgw->src_idx || !ccgw->dst_idx)
792 return err;
793 }
794
795 /* add the checks for other gwtypes here */
796
797 return 0;
798}
799
800static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh)
801{
802 struct rtcanmsg *r;
803 struct cgw_job *gwj;
804 u8 limhops = 0;
805 int err = 0;
806
807 if (!netlink_capable(skb, CAP_NET_ADMIN))
808 return -EPERM;
809
810 if (nlmsg_len(nlh) < sizeof(*r))
811 return -EINVAL;
812
813 r = nlmsg_data(nlh);
814 if (r->can_family != AF_CAN)
815 return -EPFNOSUPPORT;
816
817 /* so far we only support CAN -> CAN routings */
818 if (r->gwtype != CGW_TYPE_CAN_CAN)
819 return -EINVAL;
820
821 gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL);
822 if (!gwj)
823 return -ENOMEM;
824
825 gwj->handled_frames = 0;
826 gwj->dropped_frames = 0;
827 gwj->deleted_frames = 0;
828 gwj->flags = r->flags;
829 gwj->gwtype = r->gwtype;
830
831 err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw,
832 &limhops);
833 if (err < 0)
834 goto out;
835
836 err = -ENODEV;
837
838 /* ifindex == 0 is not allowed for job creation */
839 if (!gwj->ccgw.src_idx || !gwj->ccgw.dst_idx)
840 goto out;
841
842 gwj->src.dev = __dev_get_by_index(&init_net, gwj->ccgw.src_idx);
843
844 if (!gwj->src.dev)
845 goto out;
846
847 if (gwj->src.dev->type != ARPHRD_CAN)
848 goto out;
849
850 gwj->dst.dev = __dev_get_by_index(&init_net, gwj->ccgw.dst_idx);
851
852 if (!gwj->dst.dev)
853 goto out;
854
855 if (gwj->dst.dev->type != ARPHRD_CAN)
856 goto out;
857
858 gwj->limit_hops = limhops;
859
860 ASSERT_RTNL();
861
862 err = cgw_register_filter(gwj);
863 if (!err)
864 hlist_add_head_rcu(&gwj->list, &cgw_list);
865out:
866 if (err)
867 kmem_cache_free(cgw_cache, gwj);
868
869 return err;
870}
871
872static void cgw_remove_all_jobs(void)
873{
874 struct cgw_job *gwj = NULL;
875 struct hlist_node *nx;
876
877 ASSERT_RTNL();
878
879 hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) {
880 hlist_del(&gwj->list);
881 cgw_unregister_filter(gwj);
882 kmem_cache_free(cgw_cache, gwj);
883 }
884}
885
886static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh)
887{
888 struct cgw_job *gwj = NULL;
889 struct hlist_node *nx;
890 struct rtcanmsg *r;
891 struct cf_mod mod;
892 struct can_can_gw ccgw;
893 u8 limhops = 0;
894 int err = 0;
895
896 if (!netlink_capable(skb, CAP_NET_ADMIN))
897 return -EPERM;
898
899 if (nlmsg_len(nlh) < sizeof(*r))
900 return -EINVAL;
901
902 r = nlmsg_data(nlh);
903 if (r->can_family != AF_CAN)
904 return -EPFNOSUPPORT;
905
906 /* so far we only support CAN -> CAN routings */
907 if (r->gwtype != CGW_TYPE_CAN_CAN)
908 return -EINVAL;
909
910 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
911 if (err < 0)
912 return err;
913
914 /* two interface indices both set to 0 => remove all entries */
915 if (!ccgw.src_idx && !ccgw.dst_idx) {
916 cgw_remove_all_jobs();
917 return 0;
918 }
919
920 err = -EINVAL;
921
922 ASSERT_RTNL();
923
924 /* remove only the first matching entry */
925 hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) {
926
927 if (gwj->flags != r->flags)
928 continue;
929
930 if (gwj->limit_hops != limhops)
931 continue;
932
933 if (memcmp(&gwj->mod, &mod, sizeof(mod)))
934 continue;
935
936 /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */
937 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
938 continue;
939
940 hlist_del(&gwj->list);
941 cgw_unregister_filter(gwj);
942 kmem_cache_free(cgw_cache, gwj);
943 err = 0;
944 break;
945 }
946
947 return err;
948}
949
950static __init int cgw_module_init(void)
951{
952 /* sanitize given module parameter */
953 max_hops = clamp_t(unsigned int, max_hops, CGW_MIN_HOPS, CGW_MAX_HOPS);
954
955 pr_info("can: netlink gateway (rev " CAN_GW_VERSION ") max_hops=%d\n",
956 max_hops);
957
958 cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job),
959 0, 0, NULL);
960
961 if (!cgw_cache)
962 return -ENOMEM;
963
964 /* set notifier */
965 notifier.notifier_call = cgw_notifier;
966 register_netdevice_notifier(¬ifier);
967
968 if (__rtnl_register(PF_CAN, RTM_GETROUTE, NULL, cgw_dump_jobs, NULL)) {
969 unregister_netdevice_notifier(¬ifier);
970 kmem_cache_destroy(cgw_cache);
971 return -ENOBUFS;
972 }
973
974 /* Only the first call to __rtnl_register can fail */
975 __rtnl_register(PF_CAN, RTM_NEWROUTE, cgw_create_job, NULL, NULL);
976 __rtnl_register(PF_CAN, RTM_DELROUTE, cgw_remove_job, NULL, NULL);
977
978 return 0;
979}
980
981static __exit void cgw_module_exit(void)
982{
983 rtnl_unregister_all(PF_CAN);
984
985 unregister_netdevice_notifier(¬ifier);
986
987 rtnl_lock();
988 cgw_remove_all_jobs();
989 rtnl_unlock();
990
991 rcu_barrier(); /* Wait for completion of call_rcu()'s */
992
993 kmem_cache_destroy(cgw_cache);
994}
995
996module_init(cgw_module_init);
997module_exit(cgw_module_exit);