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