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1// SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) 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_VERSION "20190810"
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 canfd_frame and;
89 struct canfd_frame or;
90 struct canfd_frame xor;
91 struct canfd_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 canfd_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 canfd_frame *cf,
109 struct cgw_csum_xor *xor);
110 void (*crc8)(struct canfd_frame *cf,
111 struct cgw_csum_crc8 *crc8);
112 } csumfunc;
113 u32 uid;
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 canfd_frame *cf, \
155 struct cf_mod *mod) { op ; }
156
157MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id)
158MODFUNC(mod_and_len, cf->len &= mod->modframe.and.len)
159MODFUNC(mod_and_flags, cf->flags &= mod->modframe.and.flags)
160MODFUNC(mod_and_data, *(u64 *)cf->data &= *(u64 *)mod->modframe.and.data)
161MODFUNC(mod_or_id, cf->can_id |= mod->modframe.or.can_id)
162MODFUNC(mod_or_len, cf->len |= mod->modframe.or.len)
163MODFUNC(mod_or_flags, cf->flags |= mod->modframe.or.flags)
164MODFUNC(mod_or_data, *(u64 *)cf->data |= *(u64 *)mod->modframe.or.data)
165MODFUNC(mod_xor_id, cf->can_id ^= mod->modframe.xor.can_id)
166MODFUNC(mod_xor_len, cf->len ^= mod->modframe.xor.len)
167MODFUNC(mod_xor_flags, cf->flags ^= mod->modframe.xor.flags)
168MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data)
169MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id)
170MODFUNC(mod_set_len, cf->len = mod->modframe.set.len)
171MODFUNC(mod_set_flags, cf->flags = mod->modframe.set.flags)
172MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data)
173
174static void mod_and_fddata(struct canfd_frame *cf, struct cf_mod *mod)
175{
176 int i;
177
178 for (i = 0; i < CANFD_MAX_DLEN; i += 8)
179 *(u64 *)(cf->data + i) &= *(u64 *)(mod->modframe.and.data + i);
180}
181
182static void mod_or_fddata(struct canfd_frame *cf, struct cf_mod *mod)
183{
184 int i;
185
186 for (i = 0; i < CANFD_MAX_DLEN; i += 8)
187 *(u64 *)(cf->data + i) |= *(u64 *)(mod->modframe.or.data + i);
188}
189
190static void mod_xor_fddata(struct canfd_frame *cf, struct cf_mod *mod)
191{
192 int i;
193
194 for (i = 0; i < CANFD_MAX_DLEN; i += 8)
195 *(u64 *)(cf->data + i) ^= *(u64 *)(mod->modframe.xor.data + i);
196}
197
198static void mod_set_fddata(struct canfd_frame *cf, struct cf_mod *mod)
199{
200 memcpy(cf->data, mod->modframe.set.data, CANFD_MAX_DLEN);
201}
202
203static void canframecpy(struct canfd_frame *dst, struct can_frame *src)
204{
205 /* Copy the struct members separately to ensure that no uninitialized
206 * data are copied in the 3 bytes hole of the struct. This is needed
207 * to make easy compares of the data in the struct cf_mod.
208 */
209
210 dst->can_id = src->can_id;
211 dst->len = src->can_dlc;
212 *(u64 *)dst->data = *(u64 *)src->data;
213}
214
215static void canfdframecpy(struct canfd_frame *dst, struct canfd_frame *src)
216{
217 /* Copy the struct members separately to ensure that no uninitialized
218 * data are copied in the 2 bytes hole of the struct. This is needed
219 * to make easy compares of the data in the struct cf_mod.
220 */
221
222 dst->can_id = src->can_id;
223 dst->flags = src->flags;
224 dst->len = src->len;
225 memcpy(dst->data, src->data, CANFD_MAX_DLEN);
226}
227
228static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re, struct rtcanmsg *r)
229{
230 s8 dlen = CAN_MAX_DLEN;
231
232 if (r->flags & CGW_FLAGS_CAN_FD)
233 dlen = CANFD_MAX_DLEN;
234
235 /* absolute dlc values 0 .. 7 => 0 .. 7, e.g. data [0]
236 * relative to received dlc -1 .. -8 :
237 * e.g. for received dlc = 8
238 * -1 => index = 7 (data[7])
239 * -3 => index = 5 (data[5])
240 * -8 => index = 0 (data[0])
241 */
242
243 if (fr >= -dlen && fr < dlen &&
244 to >= -dlen && to < dlen &&
245 re >= -dlen && re < dlen)
246 return 0;
247 else
248 return -EINVAL;
249}
250
251static inline int calc_idx(int idx, int rx_len)
252{
253 if (idx < 0)
254 return rx_len + idx;
255 else
256 return idx;
257}
258
259static void cgw_csum_xor_rel(struct canfd_frame *cf, struct cgw_csum_xor *xor)
260{
261 int from = calc_idx(xor->from_idx, cf->len);
262 int to = calc_idx(xor->to_idx, cf->len);
263 int res = calc_idx(xor->result_idx, cf->len);
264 u8 val = xor->init_xor_val;
265 int i;
266
267 if (from < 0 || to < 0 || res < 0)
268 return;
269
270 if (from <= to) {
271 for (i = from; i <= to; i++)
272 val ^= cf->data[i];
273 } else {
274 for (i = from; i >= to; i--)
275 val ^= cf->data[i];
276 }
277
278 cf->data[res] = val;
279}
280
281static void cgw_csum_xor_pos(struct canfd_frame *cf, struct cgw_csum_xor *xor)
282{
283 u8 val = xor->init_xor_val;
284 int i;
285
286 for (i = xor->from_idx; i <= xor->to_idx; i++)
287 val ^= cf->data[i];
288
289 cf->data[xor->result_idx] = val;
290}
291
292static void cgw_csum_xor_neg(struct canfd_frame *cf, struct cgw_csum_xor *xor)
293{
294 u8 val = xor->init_xor_val;
295 int i;
296
297 for (i = xor->from_idx; i >= xor->to_idx; i--)
298 val ^= cf->data[i];
299
300 cf->data[xor->result_idx] = val;
301}
302
303static void cgw_csum_crc8_rel(struct canfd_frame *cf,
304 struct cgw_csum_crc8 *crc8)
305{
306 int from = calc_idx(crc8->from_idx, cf->len);
307 int to = calc_idx(crc8->to_idx, cf->len);
308 int res = calc_idx(crc8->result_idx, cf->len);
309 u8 crc = crc8->init_crc_val;
310 int i;
311
312 if (from < 0 || to < 0 || res < 0)
313 return;
314
315 if (from <= to) {
316 for (i = crc8->from_idx; i <= crc8->to_idx; i++)
317 crc = crc8->crctab[crc ^ cf->data[i]];
318 } else {
319 for (i = crc8->from_idx; i >= crc8->to_idx; i--)
320 crc = crc8->crctab[crc ^ cf->data[i]];
321 }
322
323 switch (crc8->profile) {
324 case CGW_CRC8PRF_1U8:
325 crc = crc8->crctab[crc ^ crc8->profile_data[0]];
326 break;
327
328 case CGW_CRC8PRF_16U8:
329 crc = crc8->crctab[crc ^ crc8->profile_data[cf->data[1] & 0xF]];
330 break;
331
332 case CGW_CRC8PRF_SFFID_XOR:
333 crc = crc8->crctab[crc ^ (cf->can_id & 0xFF) ^
334 (cf->can_id >> 8 & 0xFF)];
335 break;
336 }
337
338 cf->data[crc8->result_idx] = crc ^ crc8->final_xor_val;
339}
340
341static void cgw_csum_crc8_pos(struct canfd_frame *cf,
342 struct cgw_csum_crc8 *crc8)
343{
344 u8 crc = crc8->init_crc_val;
345 int i;
346
347 for (i = crc8->from_idx; i <= crc8->to_idx; i++)
348 crc = crc8->crctab[crc ^ cf->data[i]];
349
350 switch (crc8->profile) {
351 case CGW_CRC8PRF_1U8:
352 crc = crc8->crctab[crc ^ crc8->profile_data[0]];
353 break;
354
355 case CGW_CRC8PRF_16U8:
356 crc = crc8->crctab[crc ^ crc8->profile_data[cf->data[1] & 0xF]];
357 break;
358
359 case CGW_CRC8PRF_SFFID_XOR:
360 crc = crc8->crctab[crc ^ (cf->can_id & 0xFF) ^
361 (cf->can_id >> 8 & 0xFF)];
362 break;
363 }
364
365 cf->data[crc8->result_idx] = crc ^ crc8->final_xor_val;
366}
367
368static void cgw_csum_crc8_neg(struct canfd_frame *cf,
369 struct cgw_csum_crc8 *crc8)
370{
371 u8 crc = crc8->init_crc_val;
372 int i;
373
374 for (i = crc8->from_idx; i >= crc8->to_idx; i--)
375 crc = crc8->crctab[crc ^ cf->data[i]];
376
377 switch (crc8->profile) {
378 case CGW_CRC8PRF_1U8:
379 crc = crc8->crctab[crc ^ crc8->profile_data[0]];
380 break;
381
382 case CGW_CRC8PRF_16U8:
383 crc = crc8->crctab[crc ^ crc8->profile_data[cf->data[1] & 0xF]];
384 break;
385
386 case CGW_CRC8PRF_SFFID_XOR:
387 crc = crc8->crctab[crc ^ (cf->can_id & 0xFF) ^
388 (cf->can_id >> 8 & 0xFF)];
389 break;
390 }
391
392 cf->data[crc8->result_idx] = crc ^ crc8->final_xor_val;
393}
394
395/* the receive & process & send function */
396static void can_can_gw_rcv(struct sk_buff *skb, void *data)
397{
398 struct cgw_job *gwj = (struct cgw_job *)data;
399 struct canfd_frame *cf;
400 struct sk_buff *nskb;
401 int modidx = 0;
402
403 /* process strictly Classic CAN or CAN FD frames */
404 if (gwj->flags & CGW_FLAGS_CAN_FD) {
405 if (skb->len != CANFD_MTU)
406 return;
407 } else {
408 if (skb->len != CAN_MTU)
409 return;
410 }
411
412 /* Do not handle CAN frames routed more than 'max_hops' times.
413 * In general we should never catch this delimiter which is intended
414 * to cover a misconfiguration protection (e.g. circular CAN routes).
415 *
416 * The Controller Area Network controllers only accept CAN frames with
417 * correct CRCs - which are not visible in the controller registers.
418 * According to skbuff.h documentation the csum_start element for IP
419 * checksums is undefined/unused when ip_summed == CHECKSUM_UNNECESSARY.
420 * Only CAN skbs can be processed here which already have this property.
421 */
422
423#define cgw_hops(skb) ((skb)->csum_start)
424
425 BUG_ON(skb->ip_summed != CHECKSUM_UNNECESSARY);
426
427 if (cgw_hops(skb) >= max_hops) {
428 /* indicate deleted frames due to misconfiguration */
429 gwj->deleted_frames++;
430 return;
431 }
432
433 if (!(gwj->dst.dev->flags & IFF_UP)) {
434 gwj->dropped_frames++;
435 return;
436 }
437
438 /* is sending the skb back to the incoming interface not allowed? */
439 if (!(gwj->flags & CGW_FLAGS_CAN_IIF_TX_OK) &&
440 can_skb_prv(skb)->ifindex == gwj->dst.dev->ifindex)
441 return;
442
443 /* clone the given skb, which has not been done in can_rcv()
444 *
445 * When there is at least one modification function activated,
446 * we need to copy the skb as we want to modify skb->data.
447 */
448 if (gwj->mod.modfunc[0])
449 nskb = skb_copy(skb, GFP_ATOMIC);
450 else
451 nskb = skb_clone(skb, GFP_ATOMIC);
452
453 if (!nskb) {
454 gwj->dropped_frames++;
455 return;
456 }
457
458 /* put the incremented hop counter in the cloned skb */
459 cgw_hops(nskb) = cgw_hops(skb) + 1;
460
461 /* first processing of this CAN frame -> adjust to private hop limit */
462 if (gwj->limit_hops && cgw_hops(nskb) == 1)
463 cgw_hops(nskb) = max_hops - gwj->limit_hops + 1;
464
465 nskb->dev = gwj->dst.dev;
466
467 /* pointer to modifiable CAN frame */
468 cf = (struct canfd_frame *)nskb->data;
469
470 /* perform preprocessed modification functions if there are any */
471 while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx])
472 (*gwj->mod.modfunc[modidx++])(cf, &gwj->mod);
473
474 /* Has the CAN frame been modified? */
475 if (modidx) {
476 /* get available space for the processed CAN frame type */
477 int max_len = nskb->len - offsetof(struct canfd_frame, data);
478
479 /* dlc may have changed, make sure it fits to the CAN frame */
480 if (cf->len > max_len) {
481 /* delete frame due to misconfiguration */
482 gwj->deleted_frames++;
483 kfree_skb(nskb);
484 return;
485 }
486
487 /* check for checksum updates */
488 if (gwj->mod.csumfunc.crc8)
489 (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8);
490
491 if (gwj->mod.csumfunc.xor)
492 (*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor);
493 }
494
495 /* clear the skb timestamp if not configured the other way */
496 if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP))
497 nskb->tstamp = 0;
498
499 /* send to netdevice */
500 if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO))
501 gwj->dropped_frames++;
502 else
503 gwj->handled_frames++;
504}
505
506static inline int cgw_register_filter(struct net *net, struct cgw_job *gwj)
507{
508 return can_rx_register(net, gwj->src.dev, gwj->ccgw.filter.can_id,
509 gwj->ccgw.filter.can_mask, can_can_gw_rcv,
510 gwj, "gw", NULL);
511}
512
513static inline void cgw_unregister_filter(struct net *net, struct cgw_job *gwj)
514{
515 can_rx_unregister(net, gwj->src.dev, gwj->ccgw.filter.can_id,
516 gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj);
517}
518
519static int cgw_notifier(struct notifier_block *nb,
520 unsigned long msg, void *ptr)
521{
522 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
523 struct net *net = dev_net(dev);
524
525 if (dev->type != ARPHRD_CAN)
526 return NOTIFY_DONE;
527
528 if (msg == NETDEV_UNREGISTER) {
529 struct cgw_job *gwj = NULL;
530 struct hlist_node *nx;
531
532 ASSERT_RTNL();
533
534 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
535 if (gwj->src.dev == dev || gwj->dst.dev == dev) {
536 hlist_del(&gwj->list);
537 cgw_unregister_filter(net, gwj);
538 kmem_cache_free(cgw_cache, gwj);
539 }
540 }
541 }
542
543 return NOTIFY_DONE;
544}
545
546static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type,
547 u32 pid, u32 seq, int flags)
548{
549 struct rtcanmsg *rtcan;
550 struct nlmsghdr *nlh;
551
552 nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags);
553 if (!nlh)
554 return -EMSGSIZE;
555
556 rtcan = nlmsg_data(nlh);
557 rtcan->can_family = AF_CAN;
558 rtcan->gwtype = gwj->gwtype;
559 rtcan->flags = gwj->flags;
560
561 /* add statistics if available */
562
563 if (gwj->handled_frames) {
564 if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0)
565 goto cancel;
566 }
567
568 if (gwj->dropped_frames) {
569 if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0)
570 goto cancel;
571 }
572
573 if (gwj->deleted_frames) {
574 if (nla_put_u32(skb, CGW_DELETED, gwj->deleted_frames) < 0)
575 goto cancel;
576 }
577
578 /* check non default settings of attributes */
579
580 if (gwj->limit_hops) {
581 if (nla_put_u8(skb, CGW_LIM_HOPS, gwj->limit_hops) < 0)
582 goto cancel;
583 }
584
585 if (gwj->flags & CGW_FLAGS_CAN_FD) {
586 struct cgw_fdframe_mod mb;
587
588 if (gwj->mod.modtype.and) {
589 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
590 mb.modtype = gwj->mod.modtype.and;
591 if (nla_put(skb, CGW_FDMOD_AND, sizeof(mb), &mb) < 0)
592 goto cancel;
593 }
594
595 if (gwj->mod.modtype.or) {
596 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
597 mb.modtype = gwj->mod.modtype.or;
598 if (nla_put(skb, CGW_FDMOD_OR, sizeof(mb), &mb) < 0)
599 goto cancel;
600 }
601
602 if (gwj->mod.modtype.xor) {
603 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
604 mb.modtype = gwj->mod.modtype.xor;
605 if (nla_put(skb, CGW_FDMOD_XOR, sizeof(mb), &mb) < 0)
606 goto cancel;
607 }
608
609 if (gwj->mod.modtype.set) {
610 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
611 mb.modtype = gwj->mod.modtype.set;
612 if (nla_put(skb, CGW_FDMOD_SET, sizeof(mb), &mb) < 0)
613 goto cancel;
614 }
615 } else {
616 struct cgw_frame_mod mb;
617
618 if (gwj->mod.modtype.and) {
619 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
620 mb.modtype = gwj->mod.modtype.and;
621 if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0)
622 goto cancel;
623 }
624
625 if (gwj->mod.modtype.or) {
626 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
627 mb.modtype = gwj->mod.modtype.or;
628 if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0)
629 goto cancel;
630 }
631
632 if (gwj->mod.modtype.xor) {
633 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
634 mb.modtype = gwj->mod.modtype.xor;
635 if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0)
636 goto cancel;
637 }
638
639 if (gwj->mod.modtype.set) {
640 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
641 mb.modtype = gwj->mod.modtype.set;
642 if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0)
643 goto cancel;
644 }
645 }
646
647 if (gwj->mod.uid) {
648 if (nla_put_u32(skb, CGW_MOD_UID, gwj->mod.uid) < 0)
649 goto cancel;
650 }
651
652 if (gwj->mod.csumfunc.crc8) {
653 if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN,
654 &gwj->mod.csum.crc8) < 0)
655 goto cancel;
656 }
657
658 if (gwj->mod.csumfunc.xor) {
659 if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN,
660 &gwj->mod.csum.xor) < 0)
661 goto cancel;
662 }
663
664 if (gwj->gwtype == CGW_TYPE_CAN_CAN) {
665 if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) {
666 if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter),
667 &gwj->ccgw.filter) < 0)
668 goto cancel;
669 }
670
671 if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0)
672 goto cancel;
673
674 if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0)
675 goto cancel;
676 }
677
678 nlmsg_end(skb, nlh);
679 return 0;
680
681cancel:
682 nlmsg_cancel(skb, nlh);
683 return -EMSGSIZE;
684}
685
686/* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */
687static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb)
688{
689 struct net *net = sock_net(skb->sk);
690 struct cgw_job *gwj = NULL;
691 int idx = 0;
692 int s_idx = cb->args[0];
693
694 rcu_read_lock();
695 hlist_for_each_entry_rcu(gwj, &net->can.cgw_list, list) {
696 if (idx < s_idx)
697 goto cont;
698
699 if (cgw_put_job(skb, gwj, RTM_NEWROUTE,
700 NETLINK_CB(cb->skb).portid,
701 cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0)
702 break;
703cont:
704 idx++;
705 }
706 rcu_read_unlock();
707
708 cb->args[0] = idx;
709
710 return skb->len;
711}
712
713static const struct nla_policy cgw_policy[CGW_MAX + 1] = {
714 [CGW_MOD_AND] = { .len = sizeof(struct cgw_frame_mod) },
715 [CGW_MOD_OR] = { .len = sizeof(struct cgw_frame_mod) },
716 [CGW_MOD_XOR] = { .len = sizeof(struct cgw_frame_mod) },
717 [CGW_MOD_SET] = { .len = sizeof(struct cgw_frame_mod) },
718 [CGW_CS_XOR] = { .len = sizeof(struct cgw_csum_xor) },
719 [CGW_CS_CRC8] = { .len = sizeof(struct cgw_csum_crc8) },
720 [CGW_SRC_IF] = { .type = NLA_U32 },
721 [CGW_DST_IF] = { .type = NLA_U32 },
722 [CGW_FILTER] = { .len = sizeof(struct can_filter) },
723 [CGW_LIM_HOPS] = { .type = NLA_U8 },
724 [CGW_MOD_UID] = { .type = NLA_U32 },
725 [CGW_FDMOD_AND] = { .len = sizeof(struct cgw_fdframe_mod) },
726 [CGW_FDMOD_OR] = { .len = sizeof(struct cgw_fdframe_mod) },
727 [CGW_FDMOD_XOR] = { .len = sizeof(struct cgw_fdframe_mod) },
728 [CGW_FDMOD_SET] = { .len = sizeof(struct cgw_fdframe_mod) },
729};
730
731/* check for common and gwtype specific attributes */
732static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
733 u8 gwtype, void *gwtypeattr, u8 *limhops)
734{
735 struct nlattr *tb[CGW_MAX + 1];
736 struct rtcanmsg *r = nlmsg_data(nlh);
737 int modidx = 0;
738 int err = 0;
739
740 /* initialize modification & checksum data space */
741 memset(mod, 0, sizeof(*mod));
742
743 err = nlmsg_parse_deprecated(nlh, sizeof(struct rtcanmsg), tb,
744 CGW_MAX, cgw_policy, NULL);
745 if (err < 0)
746 return err;
747
748 if (tb[CGW_LIM_HOPS]) {
749 *limhops = nla_get_u8(tb[CGW_LIM_HOPS]);
750
751 if (*limhops < 1 || *limhops > max_hops)
752 return -EINVAL;
753 }
754
755 /* check for AND/OR/XOR/SET modifications */
756 if (r->flags & CGW_FLAGS_CAN_FD) {
757 struct cgw_fdframe_mod mb;
758
759 if (tb[CGW_FDMOD_AND]) {
760 nla_memcpy(&mb, tb[CGW_FDMOD_AND], CGW_FDMODATTR_LEN);
761
762 canfdframecpy(&mod->modframe.and, &mb.cf);
763 mod->modtype.and = mb.modtype;
764
765 if (mb.modtype & CGW_MOD_ID)
766 mod->modfunc[modidx++] = mod_and_id;
767
768 if (mb.modtype & CGW_MOD_LEN)
769 mod->modfunc[modidx++] = mod_and_len;
770
771 if (mb.modtype & CGW_MOD_FLAGS)
772 mod->modfunc[modidx++] = mod_and_flags;
773
774 if (mb.modtype & CGW_MOD_DATA)
775 mod->modfunc[modidx++] = mod_and_fddata;
776 }
777
778 if (tb[CGW_FDMOD_OR]) {
779 nla_memcpy(&mb, tb[CGW_FDMOD_OR], CGW_FDMODATTR_LEN);
780
781 canfdframecpy(&mod->modframe.or, &mb.cf);
782 mod->modtype.or = mb.modtype;
783
784 if (mb.modtype & CGW_MOD_ID)
785 mod->modfunc[modidx++] = mod_or_id;
786
787 if (mb.modtype & CGW_MOD_LEN)
788 mod->modfunc[modidx++] = mod_or_len;
789
790 if (mb.modtype & CGW_MOD_FLAGS)
791 mod->modfunc[modidx++] = mod_or_flags;
792
793 if (mb.modtype & CGW_MOD_DATA)
794 mod->modfunc[modidx++] = mod_or_fddata;
795 }
796
797 if (tb[CGW_FDMOD_XOR]) {
798 nla_memcpy(&mb, tb[CGW_FDMOD_XOR], CGW_FDMODATTR_LEN);
799
800 canfdframecpy(&mod->modframe.xor, &mb.cf);
801 mod->modtype.xor = mb.modtype;
802
803 if (mb.modtype & CGW_MOD_ID)
804 mod->modfunc[modidx++] = mod_xor_id;
805
806 if (mb.modtype & CGW_MOD_LEN)
807 mod->modfunc[modidx++] = mod_xor_len;
808
809 if (mb.modtype & CGW_MOD_FLAGS)
810 mod->modfunc[modidx++] = mod_xor_flags;
811
812 if (mb.modtype & CGW_MOD_DATA)
813 mod->modfunc[modidx++] = mod_xor_fddata;
814 }
815
816 if (tb[CGW_FDMOD_SET]) {
817 nla_memcpy(&mb, tb[CGW_FDMOD_SET], CGW_FDMODATTR_LEN);
818
819 canfdframecpy(&mod->modframe.set, &mb.cf);
820 mod->modtype.set = mb.modtype;
821
822 if (mb.modtype & CGW_MOD_ID)
823 mod->modfunc[modidx++] = mod_set_id;
824
825 if (mb.modtype & CGW_MOD_LEN)
826 mod->modfunc[modidx++] = mod_set_len;
827
828 if (mb.modtype & CGW_MOD_FLAGS)
829 mod->modfunc[modidx++] = mod_set_flags;
830
831 if (mb.modtype & CGW_MOD_DATA)
832 mod->modfunc[modidx++] = mod_set_fddata;
833 }
834 } else {
835 struct cgw_frame_mod mb;
836
837 if (tb[CGW_MOD_AND]) {
838 nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN);
839
840 canframecpy(&mod->modframe.and, &mb.cf);
841 mod->modtype.and = mb.modtype;
842
843 if (mb.modtype & CGW_MOD_ID)
844 mod->modfunc[modidx++] = mod_and_id;
845
846 if (mb.modtype & CGW_MOD_LEN)
847 mod->modfunc[modidx++] = mod_and_len;
848
849 if (mb.modtype & CGW_MOD_DATA)
850 mod->modfunc[modidx++] = mod_and_data;
851 }
852
853 if (tb[CGW_MOD_OR]) {
854 nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN);
855
856 canframecpy(&mod->modframe.or, &mb.cf);
857 mod->modtype.or = mb.modtype;
858
859 if (mb.modtype & CGW_MOD_ID)
860 mod->modfunc[modidx++] = mod_or_id;
861
862 if (mb.modtype & CGW_MOD_LEN)
863 mod->modfunc[modidx++] = mod_or_len;
864
865 if (mb.modtype & CGW_MOD_DATA)
866 mod->modfunc[modidx++] = mod_or_data;
867 }
868
869 if (tb[CGW_MOD_XOR]) {
870 nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN);
871
872 canframecpy(&mod->modframe.xor, &mb.cf);
873 mod->modtype.xor = mb.modtype;
874
875 if (mb.modtype & CGW_MOD_ID)
876 mod->modfunc[modidx++] = mod_xor_id;
877
878 if (mb.modtype & CGW_MOD_LEN)
879 mod->modfunc[modidx++] = mod_xor_len;
880
881 if (mb.modtype & CGW_MOD_DATA)
882 mod->modfunc[modidx++] = mod_xor_data;
883 }
884
885 if (tb[CGW_MOD_SET]) {
886 nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN);
887
888 canframecpy(&mod->modframe.set, &mb.cf);
889 mod->modtype.set = mb.modtype;
890
891 if (mb.modtype & CGW_MOD_ID)
892 mod->modfunc[modidx++] = mod_set_id;
893
894 if (mb.modtype & CGW_MOD_LEN)
895 mod->modfunc[modidx++] = mod_set_len;
896
897 if (mb.modtype & CGW_MOD_DATA)
898 mod->modfunc[modidx++] = mod_set_data;
899 }
900 }
901
902 /* check for checksum operations after CAN frame modifications */
903 if (modidx) {
904 if (tb[CGW_CS_CRC8]) {
905 struct cgw_csum_crc8 *c = nla_data(tb[CGW_CS_CRC8]);
906
907 err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
908 c->result_idx, r);
909 if (err)
910 return err;
911
912 nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8],
913 CGW_CS_CRC8_LEN);
914
915 /* select dedicated processing function to reduce
916 * runtime operations in receive hot path.
917 */
918 if (c->from_idx < 0 || c->to_idx < 0 ||
919 c->result_idx < 0)
920 mod->csumfunc.crc8 = cgw_csum_crc8_rel;
921 else if (c->from_idx <= c->to_idx)
922 mod->csumfunc.crc8 = cgw_csum_crc8_pos;
923 else
924 mod->csumfunc.crc8 = cgw_csum_crc8_neg;
925 }
926
927 if (tb[CGW_CS_XOR]) {
928 struct cgw_csum_xor *c = nla_data(tb[CGW_CS_XOR]);
929
930 err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
931 c->result_idx, r);
932 if (err)
933 return err;
934
935 nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR],
936 CGW_CS_XOR_LEN);
937
938 /* select dedicated processing function to reduce
939 * runtime operations in receive hot path.
940 */
941 if (c->from_idx < 0 || c->to_idx < 0 ||
942 c->result_idx < 0)
943 mod->csumfunc.xor = cgw_csum_xor_rel;
944 else if (c->from_idx <= c->to_idx)
945 mod->csumfunc.xor = cgw_csum_xor_pos;
946 else
947 mod->csumfunc.xor = cgw_csum_xor_neg;
948 }
949
950 if (tb[CGW_MOD_UID])
951 nla_memcpy(&mod->uid, tb[CGW_MOD_UID], sizeof(u32));
952 }
953
954 if (gwtype == CGW_TYPE_CAN_CAN) {
955 /* check CGW_TYPE_CAN_CAN specific attributes */
956 struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr;
957
958 memset(ccgw, 0, sizeof(*ccgw));
959
960 /* check for can_filter in attributes */
961 if (tb[CGW_FILTER])
962 nla_memcpy(&ccgw->filter, tb[CGW_FILTER],
963 sizeof(struct can_filter));
964
965 err = -ENODEV;
966
967 /* specifying two interfaces is mandatory */
968 if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF])
969 return err;
970
971 ccgw->src_idx = nla_get_u32(tb[CGW_SRC_IF]);
972 ccgw->dst_idx = nla_get_u32(tb[CGW_DST_IF]);
973
974 /* both indices set to 0 for flushing all routing entries */
975 if (!ccgw->src_idx && !ccgw->dst_idx)
976 return 0;
977
978 /* only one index set to 0 is an error */
979 if (!ccgw->src_idx || !ccgw->dst_idx)
980 return err;
981 }
982
983 /* add the checks for other gwtypes here */
984
985 return 0;
986}
987
988static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh,
989 struct netlink_ext_ack *extack)
990{
991 struct net *net = sock_net(skb->sk);
992 struct rtcanmsg *r;
993 struct cgw_job *gwj;
994 struct cf_mod mod;
995 struct can_can_gw ccgw;
996 u8 limhops = 0;
997 int err = 0;
998
999 if (!netlink_capable(skb, CAP_NET_ADMIN))
1000 return -EPERM;
1001
1002 if (nlmsg_len(nlh) < sizeof(*r))
1003 return -EINVAL;
1004
1005 r = nlmsg_data(nlh);
1006 if (r->can_family != AF_CAN)
1007 return -EPFNOSUPPORT;
1008
1009 /* so far we only support CAN -> CAN routings */
1010 if (r->gwtype != CGW_TYPE_CAN_CAN)
1011 return -EINVAL;
1012
1013 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
1014 if (err < 0)
1015 return err;
1016
1017 if (mod.uid) {
1018 ASSERT_RTNL();
1019
1020 /* check for updating an existing job with identical uid */
1021 hlist_for_each_entry(gwj, &net->can.cgw_list, list) {
1022 if (gwj->mod.uid != mod.uid)
1023 continue;
1024
1025 /* interfaces & filters must be identical */
1026 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
1027 return -EINVAL;
1028
1029 /* update modifications with disabled softirq & quit */
1030 local_bh_disable();
1031 memcpy(&gwj->mod, &mod, sizeof(mod));
1032 local_bh_enable();
1033 return 0;
1034 }
1035 }
1036
1037 /* ifindex == 0 is not allowed for job creation */
1038 if (!ccgw.src_idx || !ccgw.dst_idx)
1039 return -ENODEV;
1040
1041 gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL);
1042 if (!gwj)
1043 return -ENOMEM;
1044
1045 gwj->handled_frames = 0;
1046 gwj->dropped_frames = 0;
1047 gwj->deleted_frames = 0;
1048 gwj->flags = r->flags;
1049 gwj->gwtype = r->gwtype;
1050 gwj->limit_hops = limhops;
1051
1052 /* insert already parsed information */
1053 memcpy(&gwj->mod, &mod, sizeof(mod));
1054 memcpy(&gwj->ccgw, &ccgw, sizeof(ccgw));
1055
1056 err = -ENODEV;
1057
1058 gwj->src.dev = __dev_get_by_index(net, gwj->ccgw.src_idx);
1059
1060 if (!gwj->src.dev)
1061 goto out;
1062
1063 if (gwj->src.dev->type != ARPHRD_CAN)
1064 goto out;
1065
1066 gwj->dst.dev = __dev_get_by_index(net, gwj->ccgw.dst_idx);
1067
1068 if (!gwj->dst.dev)
1069 goto out;
1070
1071 if (gwj->dst.dev->type != ARPHRD_CAN)
1072 goto out;
1073
1074 ASSERT_RTNL();
1075
1076 err = cgw_register_filter(net, gwj);
1077 if (!err)
1078 hlist_add_head_rcu(&gwj->list, &net->can.cgw_list);
1079out:
1080 if (err)
1081 kmem_cache_free(cgw_cache, gwj);
1082
1083 return err;
1084}
1085
1086static void cgw_remove_all_jobs(struct net *net)
1087{
1088 struct cgw_job *gwj = NULL;
1089 struct hlist_node *nx;
1090
1091 ASSERT_RTNL();
1092
1093 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
1094 hlist_del(&gwj->list);
1095 cgw_unregister_filter(net, gwj);
1096 kmem_cache_free(cgw_cache, gwj);
1097 }
1098}
1099
1100static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh,
1101 struct netlink_ext_ack *extack)
1102{
1103 struct net *net = sock_net(skb->sk);
1104 struct cgw_job *gwj = NULL;
1105 struct hlist_node *nx;
1106 struct rtcanmsg *r;
1107 struct cf_mod mod;
1108 struct can_can_gw ccgw;
1109 u8 limhops = 0;
1110 int err = 0;
1111
1112 if (!netlink_capable(skb, CAP_NET_ADMIN))
1113 return -EPERM;
1114
1115 if (nlmsg_len(nlh) < sizeof(*r))
1116 return -EINVAL;
1117
1118 r = nlmsg_data(nlh);
1119 if (r->can_family != AF_CAN)
1120 return -EPFNOSUPPORT;
1121
1122 /* so far we only support CAN -> CAN routings */
1123 if (r->gwtype != CGW_TYPE_CAN_CAN)
1124 return -EINVAL;
1125
1126 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
1127 if (err < 0)
1128 return err;
1129
1130 /* two interface indices both set to 0 => remove all entries */
1131 if (!ccgw.src_idx && !ccgw.dst_idx) {
1132 cgw_remove_all_jobs(net);
1133 return 0;
1134 }
1135
1136 err = -EINVAL;
1137
1138 ASSERT_RTNL();
1139
1140 /* remove only the first matching entry */
1141 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
1142 if (gwj->flags != r->flags)
1143 continue;
1144
1145 if (gwj->limit_hops != limhops)
1146 continue;
1147
1148 /* we have a match when uid is enabled and identical */
1149 if (gwj->mod.uid || mod.uid) {
1150 if (gwj->mod.uid != mod.uid)
1151 continue;
1152 } else {
1153 /* no uid => check for identical modifications */
1154 if (memcmp(&gwj->mod, &mod, sizeof(mod)))
1155 continue;
1156 }
1157
1158 /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */
1159 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
1160 continue;
1161
1162 hlist_del(&gwj->list);
1163 cgw_unregister_filter(net, gwj);
1164 kmem_cache_free(cgw_cache, gwj);
1165 err = 0;
1166 break;
1167 }
1168
1169 return err;
1170}
1171
1172static int __net_init cangw_pernet_init(struct net *net)
1173{
1174 INIT_HLIST_HEAD(&net->can.cgw_list);
1175 return 0;
1176}
1177
1178static void __net_exit cangw_pernet_exit(struct net *net)
1179{
1180 rtnl_lock();
1181 cgw_remove_all_jobs(net);
1182 rtnl_unlock();
1183}
1184
1185static struct pernet_operations cangw_pernet_ops = {
1186 .init = cangw_pernet_init,
1187 .exit = cangw_pernet_exit,
1188};
1189
1190static __init int cgw_module_init(void)
1191{
1192 int ret;
1193
1194 /* sanitize given module parameter */
1195 max_hops = clamp_t(unsigned int, max_hops, CGW_MIN_HOPS, CGW_MAX_HOPS);
1196
1197 pr_info("can: netlink gateway (rev " CAN_GW_VERSION ") max_hops=%d\n",
1198 max_hops);
1199
1200 ret = register_pernet_subsys(&cangw_pernet_ops);
1201 if (ret)
1202 return ret;
1203
1204 ret = -ENOMEM;
1205 cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job),
1206 0, 0, NULL);
1207 if (!cgw_cache)
1208 goto out_cache_create;
1209
1210 /* set notifier */
1211 notifier.notifier_call = cgw_notifier;
1212 ret = register_netdevice_notifier(¬ifier);
1213 if (ret)
1214 goto out_register_notifier;
1215
1216 ret = rtnl_register_module(THIS_MODULE, PF_CAN, RTM_GETROUTE,
1217 NULL, cgw_dump_jobs, 0);
1218 if (ret)
1219 goto out_rtnl_register1;
1220
1221 ret = rtnl_register_module(THIS_MODULE, PF_CAN, RTM_NEWROUTE,
1222 cgw_create_job, NULL, 0);
1223 if (ret)
1224 goto out_rtnl_register2;
1225 ret = rtnl_register_module(THIS_MODULE, PF_CAN, RTM_DELROUTE,
1226 cgw_remove_job, NULL, 0);
1227 if (ret)
1228 goto out_rtnl_register3;
1229
1230 return 0;
1231
1232out_rtnl_register3:
1233 rtnl_unregister(PF_CAN, RTM_NEWROUTE);
1234out_rtnl_register2:
1235 rtnl_unregister(PF_CAN, RTM_GETROUTE);
1236out_rtnl_register1:
1237 unregister_netdevice_notifier(¬ifier);
1238out_register_notifier:
1239 kmem_cache_destroy(cgw_cache);
1240out_cache_create:
1241 unregister_pernet_subsys(&cangw_pernet_ops);
1242
1243 return ret;
1244}
1245
1246static __exit void cgw_module_exit(void)
1247{
1248 rtnl_unregister_all(PF_CAN);
1249
1250 unregister_netdevice_notifier(¬ifier);
1251
1252 unregister_pernet_subsys(&cangw_pernet_ops);
1253 rcu_barrier(); /* Wait for completion of call_rcu()'s */
1254
1255 kmem_cache_destroy(cgw_cache);
1256}
1257
1258module_init(cgw_module_init);
1259module_exit(cgw_module_exit);