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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) 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);