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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/list.h>
46#include <linux/spinlock.h>
47#include <linux/rcupdate.h>
48#include <linux/rculist.h>
49#include <linux/net.h>
50#include <linux/netdevice.h>
51#include <linux/if_arp.h>
52#include <linux/skbuff.h>
53#include <linux/can.h>
54#include <linux/can/core.h>
55#include <linux/can/gw.h>
56#include <net/rtnetlink.h>
57#include <net/net_namespace.h>
58#include <net/sock.h>
59
60#define CAN_GW_VERSION "20101209"
61static __initdata const char banner[] =
62 KERN_INFO "can: netlink gateway (rev " CAN_GW_VERSION ")\n";
63
64MODULE_DESCRIPTION("PF_CAN netlink gateway");
65MODULE_LICENSE("Dual BSD/GPL");
66MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
67MODULE_ALIAS("can-gw");
68
69static HLIST_HEAD(cgw_list);
70static struct notifier_block notifier;
71
72static struct kmem_cache *cgw_cache __read_mostly;
73
74/* structure that contains the (on-the-fly) CAN frame modifications */
75struct cf_mod {
76 struct {
77 struct can_frame and;
78 struct can_frame or;
79 struct can_frame xor;
80 struct can_frame set;
81 } modframe;
82 struct {
83 u8 and;
84 u8 or;
85 u8 xor;
86 u8 set;
87 } modtype;
88 void (*modfunc[MAX_MODFUNCTIONS])(struct can_frame *cf,
89 struct cf_mod *mod);
90
91 /* CAN frame checksum calculation after CAN frame modifications */
92 struct {
93 struct cgw_csum_xor xor;
94 struct cgw_csum_crc8 crc8;
95 } csum;
96 struct {
97 void (*xor)(struct can_frame *cf, struct cgw_csum_xor *xor);
98 void (*crc8)(struct can_frame *cf, struct cgw_csum_crc8 *crc8);
99 } csumfunc;
100};
101
102
103/*
104 * So far we just support CAN -> CAN routing and frame modifications.
105 *
106 * The internal can_can_gw structure contains data and attributes for
107 * a CAN -> CAN gateway job.
108 */
109struct can_can_gw {
110 struct can_filter filter;
111 int src_idx;
112 int dst_idx;
113};
114
115/* list entry for CAN gateways jobs */
116struct cgw_job {
117 struct hlist_node list;
118 struct rcu_head rcu;
119 u32 handled_frames;
120 u32 dropped_frames;
121 struct cf_mod mod;
122 union {
123 /* CAN frame data source */
124 struct net_device *dev;
125 } src;
126 union {
127 /* CAN frame data destination */
128 struct net_device *dev;
129 } dst;
130 union {
131 struct can_can_gw ccgw;
132 /* tbc */
133 };
134 u8 gwtype;
135 u16 flags;
136};
137
138/* modification functions that are invoked in the hot path in can_can_gw_rcv */
139
140#define MODFUNC(func, op) static void func(struct can_frame *cf, \
141 struct cf_mod *mod) { op ; }
142
143MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id)
144MODFUNC(mod_and_dlc, cf->can_dlc &= mod->modframe.and.can_dlc)
145MODFUNC(mod_and_data, *(u64 *)cf->data &= *(u64 *)mod->modframe.and.data)
146MODFUNC(mod_or_id, cf->can_id |= mod->modframe.or.can_id)
147MODFUNC(mod_or_dlc, cf->can_dlc |= mod->modframe.or.can_dlc)
148MODFUNC(mod_or_data, *(u64 *)cf->data |= *(u64 *)mod->modframe.or.data)
149MODFUNC(mod_xor_id, cf->can_id ^= mod->modframe.xor.can_id)
150MODFUNC(mod_xor_dlc, cf->can_dlc ^= mod->modframe.xor.can_dlc)
151MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data)
152MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id)
153MODFUNC(mod_set_dlc, cf->can_dlc = mod->modframe.set.can_dlc)
154MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data)
155
156static inline void canframecpy(struct can_frame *dst, struct can_frame *src)
157{
158 /*
159 * Copy the struct members separately to ensure that no uninitialized
160 * data are copied in the 3 bytes hole of the struct. This is needed
161 * to make easy compares of the data in the struct cf_mod.
162 */
163
164 dst->can_id = src->can_id;
165 dst->can_dlc = src->can_dlc;
166 *(u64 *)dst->data = *(u64 *)src->data;
167}
168
169static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re)
170{
171 /*
172 * absolute dlc values 0 .. 7 => 0 .. 7, e.g. data [0]
173 * relative to received dlc -1 .. -8 :
174 * e.g. for received dlc = 8
175 * -1 => index = 7 (data[7])
176 * -3 => index = 5 (data[5])
177 * -8 => index = 0 (data[0])
178 */
179
180 if (fr > -9 && fr < 8 &&
181 to > -9 && to < 8 &&
182 re > -9 && re < 8)
183 return 0;
184 else
185 return -EINVAL;
186}
187
188static inline int calc_idx(int idx, int rx_dlc)
189{
190 if (idx < 0)
191 return rx_dlc + idx;
192 else
193 return idx;
194}
195
196static void cgw_csum_xor_rel(struct can_frame *cf, struct cgw_csum_xor *xor)
197{
198 int from = calc_idx(xor->from_idx, cf->can_dlc);
199 int to = calc_idx(xor->to_idx, cf->can_dlc);
200 int res = calc_idx(xor->result_idx, cf->can_dlc);
201 u8 val = xor->init_xor_val;
202 int i;
203
204 if (from < 0 || to < 0 || res < 0)
205 return;
206
207 if (from <= to) {
208 for (i = from; i <= to; i++)
209 val ^= cf->data[i];
210 } else {
211 for (i = from; i >= to; i--)
212 val ^= cf->data[i];
213 }
214
215 cf->data[res] = val;
216}
217
218static void cgw_csum_xor_pos(struct can_frame *cf, struct cgw_csum_xor *xor)
219{
220 u8 val = xor->init_xor_val;
221 int i;
222
223 for (i = xor->from_idx; i <= xor->to_idx; i++)
224 val ^= cf->data[i];
225
226 cf->data[xor->result_idx] = val;
227}
228
229static void cgw_csum_xor_neg(struct can_frame *cf, struct cgw_csum_xor *xor)
230{
231 u8 val = xor->init_xor_val;
232 int i;
233
234 for (i = xor->from_idx; i >= xor->to_idx; i--)
235 val ^= cf->data[i];
236
237 cf->data[xor->result_idx] = val;
238}
239
240static void cgw_csum_crc8_rel(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
241{
242 int from = calc_idx(crc8->from_idx, cf->can_dlc);
243 int to = calc_idx(crc8->to_idx, cf->can_dlc);
244 int res = calc_idx(crc8->result_idx, cf->can_dlc);
245 u8 crc = crc8->init_crc_val;
246 int i;
247
248 if (from < 0 || to < 0 || res < 0)
249 return;
250
251 if (from <= to) {
252 for (i = crc8->from_idx; i <= crc8->to_idx; i++)
253 crc = crc8->crctab[crc^cf->data[i]];
254 } else {
255 for (i = crc8->from_idx; i >= crc8->to_idx; i--)
256 crc = crc8->crctab[crc^cf->data[i]];
257 }
258
259 switch (crc8->profile) {
260
261 case CGW_CRC8PRF_1U8:
262 crc = crc8->crctab[crc^crc8->profile_data[0]];
263 break;
264
265 case CGW_CRC8PRF_16U8:
266 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
267 break;
268
269 case CGW_CRC8PRF_SFFID_XOR:
270 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
271 (cf->can_id >> 8 & 0xFF)];
272 break;
273
274 }
275
276 cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
277}
278
279static void cgw_csum_crc8_pos(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
280{
281 u8 crc = crc8->init_crc_val;
282 int i;
283
284 for (i = crc8->from_idx; i <= crc8->to_idx; i++)
285 crc = crc8->crctab[crc^cf->data[i]];
286
287 switch (crc8->profile) {
288
289 case CGW_CRC8PRF_1U8:
290 crc = crc8->crctab[crc^crc8->profile_data[0]];
291 break;
292
293 case CGW_CRC8PRF_16U8:
294 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
295 break;
296
297 case CGW_CRC8PRF_SFFID_XOR:
298 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
299 (cf->can_id >> 8 & 0xFF)];
300 break;
301 }
302
303 cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
304}
305
306static void cgw_csum_crc8_neg(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
307{
308 u8 crc = crc8->init_crc_val;
309 int i;
310
311 for (i = crc8->from_idx; i >= crc8->to_idx; i--)
312 crc = crc8->crctab[crc^cf->data[i]];
313
314 switch (crc8->profile) {
315
316 case CGW_CRC8PRF_1U8:
317 crc = crc8->crctab[crc^crc8->profile_data[0]];
318 break;
319
320 case CGW_CRC8PRF_16U8:
321 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
322 break;
323
324 case CGW_CRC8PRF_SFFID_XOR:
325 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
326 (cf->can_id >> 8 & 0xFF)];
327 break;
328 }
329
330 cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
331}
332
333/* the receive & process & send function */
334static void can_can_gw_rcv(struct sk_buff *skb, void *data)
335{
336 struct cgw_job *gwj = (struct cgw_job *)data;
337 struct can_frame *cf;
338 struct sk_buff *nskb;
339 int modidx = 0;
340
341 /* do not handle already routed frames - see comment below */
342 if (skb_mac_header_was_set(skb))
343 return;
344
345 if (!(gwj->dst.dev->flags & IFF_UP)) {
346 gwj->dropped_frames++;
347 return;
348 }
349
350 /*
351 * clone the given skb, which has not been done in can_rcv()
352 *
353 * When there is at least one modification function activated,
354 * we need to copy the skb as we want to modify skb->data.
355 */
356 if (gwj->mod.modfunc[0])
357 nskb = skb_copy(skb, GFP_ATOMIC);
358 else
359 nskb = skb_clone(skb, GFP_ATOMIC);
360
361 if (!nskb) {
362 gwj->dropped_frames++;
363 return;
364 }
365
366 /*
367 * Mark routed frames by setting some mac header length which is
368 * not relevant for the CAN frames located in the skb->data section.
369 *
370 * As dev->header_ops is not set in CAN netdevices no one is ever
371 * accessing the various header offsets in the CAN skbuffs anyway.
372 * E.g. using the packet socket to read CAN frames is still working.
373 */
374 skb_set_mac_header(nskb, 8);
375 nskb->dev = gwj->dst.dev;
376
377 /* pointer to modifiable CAN frame */
378 cf = (struct can_frame *)nskb->data;
379
380 /* perform preprocessed modification functions if there are any */
381 while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx])
382 (*gwj->mod.modfunc[modidx++])(cf, &gwj->mod);
383
384 /* check for checksum updates when the CAN frame has been modified */
385 if (modidx) {
386 if (gwj->mod.csumfunc.crc8)
387 (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8);
388
389 if (gwj->mod.csumfunc.xor)
390 (*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor);
391 }
392
393 /* clear the skb timestamp if not configured the other way */
394 if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP))
395 nskb->tstamp.tv64 = 0;
396
397 /* send to netdevice */
398 if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO))
399 gwj->dropped_frames++;
400 else
401 gwj->handled_frames++;
402}
403
404static inline int cgw_register_filter(struct cgw_job *gwj)
405{
406 return can_rx_register(gwj->src.dev, gwj->ccgw.filter.can_id,
407 gwj->ccgw.filter.can_mask, can_can_gw_rcv,
408 gwj, "gw");
409}
410
411static inline void cgw_unregister_filter(struct cgw_job *gwj)
412{
413 can_rx_unregister(gwj->src.dev, gwj->ccgw.filter.can_id,
414 gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj);
415}
416
417static int cgw_notifier(struct notifier_block *nb,
418 unsigned long msg, void *data)
419{
420 struct net_device *dev = (struct net_device *)data;
421
422 if (!net_eq(dev_net(dev), &init_net))
423 return NOTIFY_DONE;
424 if (dev->type != ARPHRD_CAN)
425 return NOTIFY_DONE;
426
427 if (msg == NETDEV_UNREGISTER) {
428
429 struct cgw_job *gwj = NULL;
430 struct hlist_node *n, *nx;
431
432 ASSERT_RTNL();
433
434 hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
435
436 if (gwj->src.dev == dev || gwj->dst.dev == dev) {
437 hlist_del(&gwj->list);
438 cgw_unregister_filter(gwj);
439 kfree(gwj);
440 }
441 }
442 }
443
444 return NOTIFY_DONE;
445}
446
447static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj)
448{
449 struct cgw_frame_mod mb;
450 struct rtcanmsg *rtcan;
451 struct nlmsghdr *nlh = nlmsg_put(skb, 0, 0, 0, sizeof(*rtcan), 0);
452 if (!nlh)
453 return -EMSGSIZE;
454
455 rtcan = nlmsg_data(nlh);
456 rtcan->can_family = AF_CAN;
457 rtcan->gwtype = gwj->gwtype;
458 rtcan->flags = gwj->flags;
459
460 /* add statistics if available */
461
462 if (gwj->handled_frames) {
463 if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0)
464 goto cancel;
465 else
466 nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(u32));
467 }
468
469 if (gwj->dropped_frames) {
470 if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0)
471 goto cancel;
472 else
473 nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(u32));
474 }
475
476 /* check non default settings of attributes */
477
478 if (gwj->mod.modtype.and) {
479 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
480 mb.modtype = gwj->mod.modtype.and;
481 if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0)
482 goto cancel;
483 else
484 nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(mb));
485 }
486
487 if (gwj->mod.modtype.or) {
488 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
489 mb.modtype = gwj->mod.modtype.or;
490 if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0)
491 goto cancel;
492 else
493 nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(mb));
494 }
495
496 if (gwj->mod.modtype.xor) {
497 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
498 mb.modtype = gwj->mod.modtype.xor;
499 if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0)
500 goto cancel;
501 else
502 nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(mb));
503 }
504
505 if (gwj->mod.modtype.set) {
506 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
507 mb.modtype = gwj->mod.modtype.set;
508 if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0)
509 goto cancel;
510 else
511 nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(mb));
512 }
513
514 if (gwj->mod.csumfunc.crc8) {
515 if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN,
516 &gwj->mod.csum.crc8) < 0)
517 goto cancel;
518 else
519 nlh->nlmsg_len += NLA_HDRLEN + \
520 NLA_ALIGN(CGW_CS_CRC8_LEN);
521 }
522
523 if (gwj->mod.csumfunc.xor) {
524 if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN,
525 &gwj->mod.csum.xor) < 0)
526 goto cancel;
527 else
528 nlh->nlmsg_len += NLA_HDRLEN + \
529 NLA_ALIGN(CGW_CS_XOR_LEN);
530 }
531
532 if (gwj->gwtype == CGW_TYPE_CAN_CAN) {
533
534 if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) {
535 if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter),
536 &gwj->ccgw.filter) < 0)
537 goto cancel;
538 else
539 nlh->nlmsg_len += NLA_HDRLEN +
540 NLA_ALIGN(sizeof(struct can_filter));
541 }
542
543 if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0)
544 goto cancel;
545 else
546 nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(u32));
547
548 if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0)
549 goto cancel;
550 else
551 nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(u32));
552 }
553
554 return skb->len;
555
556cancel:
557 nlmsg_cancel(skb, nlh);
558 return -EMSGSIZE;
559}
560
561/* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */
562static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb)
563{
564 struct cgw_job *gwj = NULL;
565 struct hlist_node *n;
566 int idx = 0;
567 int s_idx = cb->args[0];
568
569 rcu_read_lock();
570 hlist_for_each_entry_rcu(gwj, n, &cgw_list, list) {
571 if (idx < s_idx)
572 goto cont;
573
574 if (cgw_put_job(skb, gwj) < 0)
575 break;
576cont:
577 idx++;
578 }
579 rcu_read_unlock();
580
581 cb->args[0] = idx;
582
583 return skb->len;
584}
585
586/* check for common and gwtype specific attributes */
587static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
588 u8 gwtype, void *gwtypeattr)
589{
590 struct nlattr *tb[CGW_MAX+1];
591 struct cgw_frame_mod mb;
592 int modidx = 0;
593 int err = 0;
594
595 /* initialize modification & checksum data space */
596 memset(mod, 0, sizeof(*mod));
597
598 err = nlmsg_parse(nlh, sizeof(struct rtcanmsg), tb, CGW_MAX, NULL);
599 if (err < 0)
600 return err;
601
602 /* check for AND/OR/XOR/SET modifications */
603
604 if (tb[CGW_MOD_AND] &&
605 nla_len(tb[CGW_MOD_AND]) == CGW_MODATTR_LEN) {
606 nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN);
607
608 canframecpy(&mod->modframe.and, &mb.cf);
609 mod->modtype.and = mb.modtype;
610
611 if (mb.modtype & CGW_MOD_ID)
612 mod->modfunc[modidx++] = mod_and_id;
613
614 if (mb.modtype & CGW_MOD_DLC)
615 mod->modfunc[modidx++] = mod_and_dlc;
616
617 if (mb.modtype & CGW_MOD_DATA)
618 mod->modfunc[modidx++] = mod_and_data;
619 }
620
621 if (tb[CGW_MOD_OR] &&
622 nla_len(tb[CGW_MOD_OR]) == CGW_MODATTR_LEN) {
623 nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN);
624
625 canframecpy(&mod->modframe.or, &mb.cf);
626 mod->modtype.or = mb.modtype;
627
628 if (mb.modtype & CGW_MOD_ID)
629 mod->modfunc[modidx++] = mod_or_id;
630
631 if (mb.modtype & CGW_MOD_DLC)
632 mod->modfunc[modidx++] = mod_or_dlc;
633
634 if (mb.modtype & CGW_MOD_DATA)
635 mod->modfunc[modidx++] = mod_or_data;
636 }
637
638 if (tb[CGW_MOD_XOR] &&
639 nla_len(tb[CGW_MOD_XOR]) == CGW_MODATTR_LEN) {
640 nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN);
641
642 canframecpy(&mod->modframe.xor, &mb.cf);
643 mod->modtype.xor = mb.modtype;
644
645 if (mb.modtype & CGW_MOD_ID)
646 mod->modfunc[modidx++] = mod_xor_id;
647
648 if (mb.modtype & CGW_MOD_DLC)
649 mod->modfunc[modidx++] = mod_xor_dlc;
650
651 if (mb.modtype & CGW_MOD_DATA)
652 mod->modfunc[modidx++] = mod_xor_data;
653 }
654
655 if (tb[CGW_MOD_SET] &&
656 nla_len(tb[CGW_MOD_SET]) == CGW_MODATTR_LEN) {
657 nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN);
658
659 canframecpy(&mod->modframe.set, &mb.cf);
660 mod->modtype.set = mb.modtype;
661
662 if (mb.modtype & CGW_MOD_ID)
663 mod->modfunc[modidx++] = mod_set_id;
664
665 if (mb.modtype & CGW_MOD_DLC)
666 mod->modfunc[modidx++] = mod_set_dlc;
667
668 if (mb.modtype & CGW_MOD_DATA)
669 mod->modfunc[modidx++] = mod_set_data;
670 }
671
672 /* check for checksum operations after CAN frame modifications */
673 if (modidx) {
674
675 if (tb[CGW_CS_CRC8] &&
676 nla_len(tb[CGW_CS_CRC8]) == CGW_CS_CRC8_LEN) {
677
678 struct cgw_csum_crc8 *c = (struct cgw_csum_crc8 *)\
679 nla_data(tb[CGW_CS_CRC8]);
680
681 err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
682 c->result_idx);
683 if (err)
684 return err;
685
686 nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8],
687 CGW_CS_CRC8_LEN);
688
689 /*
690 * select dedicated processing function to reduce
691 * runtime operations in receive hot path.
692 */
693 if (c->from_idx < 0 || c->to_idx < 0 ||
694 c->result_idx < 0)
695 mod->csumfunc.crc8 = cgw_csum_crc8_rel;
696 else if (c->from_idx <= c->to_idx)
697 mod->csumfunc.crc8 = cgw_csum_crc8_pos;
698 else
699 mod->csumfunc.crc8 = cgw_csum_crc8_neg;
700 }
701
702 if (tb[CGW_CS_XOR] &&
703 nla_len(tb[CGW_CS_XOR]) == CGW_CS_XOR_LEN) {
704
705 struct cgw_csum_xor *c = (struct cgw_csum_xor *)\
706 nla_data(tb[CGW_CS_XOR]);
707
708 err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
709 c->result_idx);
710 if (err)
711 return err;
712
713 nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR],
714 CGW_CS_XOR_LEN);
715
716 /*
717 * select dedicated processing function to reduce
718 * runtime operations in receive hot path.
719 */
720 if (c->from_idx < 0 || c->to_idx < 0 ||
721 c->result_idx < 0)
722 mod->csumfunc.xor = cgw_csum_xor_rel;
723 else if (c->from_idx <= c->to_idx)
724 mod->csumfunc.xor = cgw_csum_xor_pos;
725 else
726 mod->csumfunc.xor = cgw_csum_xor_neg;
727 }
728 }
729
730 if (gwtype == CGW_TYPE_CAN_CAN) {
731
732 /* check CGW_TYPE_CAN_CAN specific attributes */
733
734 struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr;
735 memset(ccgw, 0, sizeof(*ccgw));
736
737 /* check for can_filter in attributes */
738 if (tb[CGW_FILTER] &&
739 nla_len(tb[CGW_FILTER]) == sizeof(struct can_filter))
740 nla_memcpy(&ccgw->filter, tb[CGW_FILTER],
741 sizeof(struct can_filter));
742
743 err = -ENODEV;
744
745 /* specifying two interfaces is mandatory */
746 if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF])
747 return err;
748
749 if (nla_len(tb[CGW_SRC_IF]) == sizeof(u32))
750 nla_memcpy(&ccgw->src_idx, tb[CGW_SRC_IF],
751 sizeof(u32));
752
753 if (nla_len(tb[CGW_DST_IF]) == sizeof(u32))
754 nla_memcpy(&ccgw->dst_idx, tb[CGW_DST_IF],
755 sizeof(u32));
756
757 /* both indices set to 0 for flushing all routing entries */
758 if (!ccgw->src_idx && !ccgw->dst_idx)
759 return 0;
760
761 /* only one index set to 0 is an error */
762 if (!ccgw->src_idx || !ccgw->dst_idx)
763 return err;
764 }
765
766 /* add the checks for other gwtypes here */
767
768 return 0;
769}
770
771static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh,
772 void *arg)
773{
774 struct rtcanmsg *r;
775 struct cgw_job *gwj;
776 int err = 0;
777
778 if (nlmsg_len(nlh) < sizeof(*r))
779 return -EINVAL;
780
781 r = nlmsg_data(nlh);
782 if (r->can_family != AF_CAN)
783 return -EPFNOSUPPORT;
784
785 /* so far we only support CAN -> CAN routings */
786 if (r->gwtype != CGW_TYPE_CAN_CAN)
787 return -EINVAL;
788
789 gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL);
790 if (!gwj)
791 return -ENOMEM;
792
793 gwj->handled_frames = 0;
794 gwj->dropped_frames = 0;
795 gwj->flags = r->flags;
796 gwj->gwtype = r->gwtype;
797
798 err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw);
799 if (err < 0)
800 goto out;
801
802 err = -ENODEV;
803
804 /* ifindex == 0 is not allowed for job creation */
805 if (!gwj->ccgw.src_idx || !gwj->ccgw.dst_idx)
806 goto out;
807
808 gwj->src.dev = dev_get_by_index(&init_net, gwj->ccgw.src_idx);
809
810 if (!gwj->src.dev)
811 goto out;
812
813 /* check for CAN netdev not using header_ops - see gw_rcv() */
814 if (gwj->src.dev->type != ARPHRD_CAN || gwj->src.dev->header_ops)
815 goto put_src_out;
816
817 gwj->dst.dev = dev_get_by_index(&init_net, gwj->ccgw.dst_idx);
818
819 if (!gwj->dst.dev)
820 goto put_src_out;
821
822 /* check for CAN netdev not using header_ops - see gw_rcv() */
823 if (gwj->dst.dev->type != ARPHRD_CAN || gwj->dst.dev->header_ops)
824 goto put_src_dst_out;
825
826 ASSERT_RTNL();
827
828 err = cgw_register_filter(gwj);
829 if (!err)
830 hlist_add_head_rcu(&gwj->list, &cgw_list);
831
832put_src_dst_out:
833 dev_put(gwj->dst.dev);
834put_src_out:
835 dev_put(gwj->src.dev);
836out:
837 if (err)
838 kmem_cache_free(cgw_cache, gwj);
839
840 return err;
841}
842
843static void cgw_remove_all_jobs(void)
844{
845 struct cgw_job *gwj = NULL;
846 struct hlist_node *n, *nx;
847
848 ASSERT_RTNL();
849
850 hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
851 hlist_del(&gwj->list);
852 cgw_unregister_filter(gwj);
853 kfree(gwj);
854 }
855}
856
857static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
858{
859 struct cgw_job *gwj = NULL;
860 struct hlist_node *n, *nx;
861 struct rtcanmsg *r;
862 struct cf_mod mod;
863 struct can_can_gw ccgw;
864 int err = 0;
865
866 if (nlmsg_len(nlh) < sizeof(*r))
867 return -EINVAL;
868
869 r = nlmsg_data(nlh);
870 if (r->can_family != AF_CAN)
871 return -EPFNOSUPPORT;
872
873 /* so far we only support CAN -> CAN routings */
874 if (r->gwtype != CGW_TYPE_CAN_CAN)
875 return -EINVAL;
876
877 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw);
878 if (err < 0)
879 return err;
880
881 /* two interface indices both set to 0 => remove all entries */
882 if (!ccgw.src_idx && !ccgw.dst_idx) {
883 cgw_remove_all_jobs();
884 return 0;
885 }
886
887 err = -EINVAL;
888
889 ASSERT_RTNL();
890
891 /* remove only the first matching entry */
892 hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
893
894 if (gwj->flags != r->flags)
895 continue;
896
897 if (memcmp(&gwj->mod, &mod, sizeof(mod)))
898 continue;
899
900 /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */
901 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
902 continue;
903
904 hlist_del(&gwj->list);
905 cgw_unregister_filter(gwj);
906 kfree(gwj);
907 err = 0;
908 break;
909 }
910
911 return err;
912}
913
914static __init int cgw_module_init(void)
915{
916 printk(banner);
917
918 cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job),
919 0, 0, NULL);
920
921 if (!cgw_cache)
922 return -ENOMEM;
923
924 /* set notifier */
925 notifier.notifier_call = cgw_notifier;
926 register_netdevice_notifier(¬ifier);
927
928 if (__rtnl_register(PF_CAN, RTM_GETROUTE, NULL, cgw_dump_jobs, NULL)) {
929 unregister_netdevice_notifier(¬ifier);
930 kmem_cache_destroy(cgw_cache);
931 return -ENOBUFS;
932 }
933
934 /* Only the first call to __rtnl_register can fail */
935 __rtnl_register(PF_CAN, RTM_NEWROUTE, cgw_create_job, NULL, NULL);
936 __rtnl_register(PF_CAN, RTM_DELROUTE, cgw_remove_job, NULL, NULL);
937
938 return 0;
939}
940
941static __exit void cgw_module_exit(void)
942{
943 rtnl_unregister_all(PF_CAN);
944
945 unregister_netdevice_notifier(¬ifier);
946
947 rtnl_lock();
948 cgw_remove_all_jobs();
949 rtnl_unlock();
950
951 rcu_barrier(); /* Wait for completion of call_rcu()'s */
952
953 kmem_cache_destroy(cgw_cache);
954}
955
956module_init(cgw_module_init);
957module_exit(cgw_module_exit);