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Linux 4.13.16
[linux/fpc-iii.git] / net / can / gw.c
blob29748d844c3fac1bda35d494cdc1474fe81849a9
1 /*
2 * gw.c - CAN frame Gateway/Router/Bridge with netlink interface
3 *
4 * Copyright (c) 2017 Volkswagen Group Electronic Research
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of Volkswagen nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * Alternatively, provided that this notice is retained in full, this
20 * software may be distributed under the terms of the GNU General
21 * Public License ("GPL") version 2, in which case the provisions of the
22 * GPL apply INSTEAD OF those given above.
23 *
24 * The provided data structures and external interfaces from this code
25 * are not restricted to be used by modules with a GPL compatible license.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
30 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
31 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
32 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
33 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
37 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
38 * DAMAGE.
39 *
40 */
41
42 #include <linux/module.h>
43 #include <linux/init.h>
44 #include <linux/types.h>
45 #include <linux/kernel.h>
46 #include <linux/list.h>
47 #include <linux/spinlock.h>
48 #include <linux/rcupdate.h>
49 #include <linux/rculist.h>
50 #include <linux/net.h>
51 #include <linux/netdevice.h>
52 #include <linux/if_arp.h>
53 #include <linux/skbuff.h>
54 #include <linux/can.h>
55 #include <linux/can/core.h>
56 #include <linux/can/skb.h>
57 #include <linux/can/gw.h>
58 #include <net/rtnetlink.h>
59 #include <net/net_namespace.h>
60 #include <net/sock.h>
61
62 #define CAN_GW_VERSION "20170425"
63 #define CAN_GW_NAME "can-gw"
64
65 MODULE_DESCRIPTION("PF_CAN netlink gateway");
66 MODULE_LICENSE("Dual BSD/GPL");
67 MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
68 MODULE_ALIAS(CAN_GW_NAME);
69
70 #define CGW_MIN_HOPS 1
71 #define CGW_MAX_HOPS 6
72 #define CGW_DEFAULT_HOPS 1
73
74 static unsigned int max_hops __read_mostly = CGW_DEFAULT_HOPS;
75 module_param(max_hops, uint, S_IRUGO);
76 MODULE_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
82 static struct notifier_block notifier;
83 static struct kmem_cache *cgw_cache __read_mostly;
84
85 /* structure that contains the (on-the-fly) CAN frame modifications */
86 struct cf_mod {
87 struct {
88 struct can_frame and;
89 struct can_frame or;
90 struct can_frame xor;
91 struct can_frame set;
92 } modframe;
93 struct {
94 u8 and;
95 u8 or;
96 u8 xor;
97 u8 set;
98 } modtype;
99 void (*modfunc[MAX_MODFUNCTIONS])(struct can_frame *cf,
100 struct cf_mod *mod);
101
102 /* CAN frame checksum calculation after CAN frame modifications */
103 struct {
104 struct cgw_csum_xor xor;
105 struct cgw_csum_crc8 crc8;
106 } csum;
107 struct {
108 void (*xor)(struct can_frame *cf, struct cgw_csum_xor *xor);
109 void (*crc8)(struct can_frame *cf, struct cgw_csum_crc8 *crc8);
110 } csumfunc;
111 u32 uid;
112 };
113
114
115 /*
116 * So far we just support CAN -> CAN routing and frame modifications.
117 *
118 * The internal can_can_gw structure contains data and attributes for
119 * a CAN -> CAN gateway job.
120 */
121 struct 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 */
128 struct cgw_job {
129 struct hlist_node list;
130 struct rcu_head rcu;
131 u32 handled_frames;
132 u32 dropped_frames;
133 u32 deleted_frames;
134 struct cf_mod mod;
135 union {
136 /* CAN frame data source */
137 struct net_device *dev;
138 } src;
139 union {
140 /* CAN frame data destination */
141 struct net_device *dev;
142 } dst;
143 union {
144 struct can_can_gw ccgw;
145 /* tbc */
146 };
147 u8 gwtype;
148 u8 limit_hops;
149 u16 flags;
150 };
151
152 /* modification functions that are invoked in the hot path in can_can_gw_rcv */
153
154 #define MODFUNC(func, op) static void func(struct can_frame *cf, \
155 struct cf_mod *mod) { op ; }
156
157 MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id)
158 MODFUNC(mod_and_dlc, cf->can_dlc &= mod->modframe.and.can_dlc)
159 MODFUNC(mod_and_data, *(u64 *)cf->data &= *(u64 *)mod->modframe.and.data)
160 MODFUNC(mod_or_id, cf->can_id |= mod->modframe.or.can_id)
161 MODFUNC(mod_or_dlc, cf->can_dlc |= mod->modframe.or.can_dlc)
162 MODFUNC(mod_or_data, *(u64 *)cf->data |= *(u64 *)mod->modframe.or.data)
163 MODFUNC(mod_xor_id, cf->can_id ^= mod->modframe.xor.can_id)
164 MODFUNC(mod_xor_dlc, cf->can_dlc ^= mod->modframe.xor.can_dlc)
165 MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data)
166 MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id)
167 MODFUNC(mod_set_dlc, cf->can_dlc = mod->modframe.set.can_dlc)
168 MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data)
169
170 static inline void canframecpy(struct can_frame *dst, struct can_frame *src)
171 {
172 /*
173 * Copy the struct members separately to ensure that no uninitialized
174 * data are copied in the 3 bytes hole of the struct. This is needed
175 * to make easy compares of the data in the struct cf_mod.
176 */
177
178 dst->can_id = src->can_id;
179 dst->can_dlc = src->can_dlc;
180 *(u64 *)dst->data = *(u64 *)src->data;
181 }
182
183 static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re)
184 {
185 /*
186 * absolute dlc values 0 .. 7 => 0 .. 7, e.g. data [0]
187 * relative to received dlc -1 .. -8 :
188 * e.g. for received dlc = 8
189 * -1 => index = 7 (data[7])
190 * -3 => index = 5 (data[5])
191 * -8 => index = 0 (data[0])
192 */
193
194 if (fr > -9 && fr < 8 &&
195 to > -9 && to < 8 &&
196 re > -9 && re < 8)
197 return 0;
198 else
199 return -EINVAL;
200 }
201
202 static inline int calc_idx(int idx, int rx_dlc)
203 {
204 if (idx < 0)
205 return rx_dlc + idx;
206 else
207 return idx;
208 }
209
210 static void cgw_csum_xor_rel(struct can_frame *cf, struct cgw_csum_xor *xor)
211 {
212 int from = calc_idx(xor->from_idx, cf->can_dlc);
213 int to = calc_idx(xor->to_idx, cf->can_dlc);
214 int res = calc_idx(xor->result_idx, cf->can_dlc);
215 u8 val = xor->init_xor_val;
216 int i;
217
218 if (from < 0 || to < 0 || res < 0)
219 return;
220
221 if (from <= to) {
222 for (i = from; i <= to; i++)
223 val ^= cf->data[i];
224 } else {
225 for (i = from; i >= to; i--)
226 val ^= cf->data[i];
227 }
228
229 cf->data[res] = val;
230 }
231
232 static void cgw_csum_xor_pos(struct can_frame *cf, struct cgw_csum_xor *xor)
233 {
234 u8 val = xor->init_xor_val;
235 int i;
236
237 for (i = xor->from_idx; i <= xor->to_idx; i++)
238 val ^= cf->data[i];
239
240 cf->data[xor->result_idx] = val;
241 }
242
243 static void cgw_csum_xor_neg(struct can_frame *cf, struct cgw_csum_xor *xor)
244 {
245 u8 val = xor->init_xor_val;
246 int i;
247
248 for (i = xor->from_idx; i >= xor->to_idx; i--)
249 val ^= cf->data[i];
250
251 cf->data[xor->result_idx] = val;
252 }
253
254 static void cgw_csum_crc8_rel(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
255 {
256 int from = calc_idx(crc8->from_idx, cf->can_dlc);
257 int to = calc_idx(crc8->to_idx, cf->can_dlc);
258 int res = calc_idx(crc8->result_idx, cf->can_dlc);
259 u8 crc = crc8->init_crc_val;
260 int i;
261
262 if (from < 0 || to < 0 || res < 0)
263 return;
264
265 if (from <= to) {
266 for (i = crc8->from_idx; i <= crc8->to_idx; i++)
267 crc = crc8->crctab[crc^cf->data[i]];
268 } else {
269 for (i = crc8->from_idx; i >= crc8->to_idx; i--)
270 crc = crc8->crctab[crc^cf->data[i]];
271 }
272
273 switch (crc8->profile) {
274
275 case CGW_CRC8PRF_1U8:
276 crc = crc8->crctab[crc^crc8->profile_data[0]];
277 break;
278
279 case CGW_CRC8PRF_16U8:
280 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
281 break;
282
283 case CGW_CRC8PRF_SFFID_XOR:
284 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
285 (cf->can_id >> 8 & 0xFF)];
286 break;
287
288 }
289
290 cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
291 }
292
293 static void cgw_csum_crc8_pos(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
294 {
295 u8 crc = crc8->init_crc_val;
296 int i;
297
298 for (i = crc8->from_idx; i <= crc8->to_idx; i++)
299 crc = crc8->crctab[crc^cf->data[i]];
300
301 switch (crc8->profile) {
302
303 case CGW_CRC8PRF_1U8:
304 crc = crc8->crctab[crc^crc8->profile_data[0]];
305 break;
306
307 case CGW_CRC8PRF_16U8:
308 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
309 break;
310
311 case CGW_CRC8PRF_SFFID_XOR:
312 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
313 (cf->can_id >> 8 & 0xFF)];
314 break;
315 }
316
317 cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
318 }
319
320 static void cgw_csum_crc8_neg(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
321 {
322 u8 crc = crc8->init_crc_val;
323 int i;
324
325 for (i = crc8->from_idx; i >= crc8->to_idx; i--)
326 crc = crc8->crctab[crc^cf->data[i]];
327
328 switch (crc8->profile) {
329
330 case CGW_CRC8PRF_1U8:
331 crc = crc8->crctab[crc^crc8->profile_data[0]];
332 break;
333
334 case CGW_CRC8PRF_16U8:
335 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
336 break;
337
338 case CGW_CRC8PRF_SFFID_XOR:
339 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
340 (cf->can_id >> 8 & 0xFF)];
341 break;
342 }
343
344 cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
345 }
346
347 /* the receive & process & send function */
348 static void can_can_gw_rcv(struct sk_buff *skb, void *data)
349 {
350 struct cgw_job *gwj = (struct cgw_job *)data;
351 struct can_frame *cf;
352 struct sk_buff *nskb;
353 int modidx = 0;
354
355 /*
356 * Do not handle CAN frames routed more than 'max_hops' times.
357 * In general we should never catch this delimiter which is intended
358 * to cover a misconfiguration protection (e.g. circular CAN routes).
359 *
360 * The Controller Area Network controllers only accept CAN frames with
361 * correct CRCs - which are not visible in the controller registers.
362 * According to skbuff.h documentation the csum_start element for IP
363 * checksums is undefined/unused when ip_summed == CHECKSUM_UNNECESSARY.
364 * Only CAN skbs can be processed here which already have this property.
365 */
366
367 #define cgw_hops(skb) ((skb)->csum_start)
368
369 BUG_ON(skb->ip_summed != CHECKSUM_UNNECESSARY);
370
371 if (cgw_hops(skb) >= max_hops) {
372 /* indicate deleted frames due to misconfiguration */
373 gwj->deleted_frames++;
374 return;
375 }
376
377 if (!(gwj->dst.dev->flags & IFF_UP)) {
378 gwj->dropped_frames++;
379 return;
380 }
381
382 /* is sending the skb back to the incoming interface not allowed? */
383 if (!(gwj->flags & CGW_FLAGS_CAN_IIF_TX_OK) &&
384 can_skb_prv(skb)->ifindex == gwj->dst.dev->ifindex)
385 return;
386
387 /*
388 * clone the given skb, which has not been done in can_rcv()
389 *
390 * When there is at least one modification function activated,
391 * we need to copy the skb as we want to modify skb->data.
392 */
393 if (gwj->mod.modfunc[0])
394 nskb = skb_copy(skb, GFP_ATOMIC);
395 else
396 nskb = skb_clone(skb, GFP_ATOMIC);
397
398 if (!nskb) {
399 gwj->dropped_frames++;
400 return;
401 }
402
403 /* put the incremented hop counter in the cloned skb */
404 cgw_hops(nskb) = cgw_hops(skb) + 1;
405
406 /* first processing of this CAN frame -> adjust to private hop limit */
407 if (gwj->limit_hops && cgw_hops(nskb) == 1)
408 cgw_hops(nskb) = max_hops - gwj->limit_hops + 1;
409
410 nskb->dev = gwj->dst.dev;
411
412 /* pointer to modifiable CAN frame */
413 cf = (struct can_frame *)nskb->data;
414
415 /* perform preprocessed modification functions if there are any */
416 while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx])
417 (*gwj->mod.modfunc[modidx++])(cf, &gwj->mod);
418
419 /* check for checksum updates when the CAN frame has been modified */
420 if (modidx) {
421 if (gwj->mod.csumfunc.crc8)
422 (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8);
423
424 if (gwj->mod.csumfunc.xor)
425 (*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor);
426 }
427
428 /* clear the skb timestamp if not configured the other way */
429 if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP))
430 nskb->tstamp = 0;
431
432 /* send to netdevice */
433 if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO))
434 gwj->dropped_frames++;
435 else
436 gwj->handled_frames++;
437 }
438
439 static inline int cgw_register_filter(struct net *net, struct cgw_job *gwj)
440 {
441 return can_rx_register(net, gwj->src.dev, gwj->ccgw.filter.can_id,
442 gwj->ccgw.filter.can_mask, can_can_gw_rcv,
443 gwj, "gw", NULL);
444 }
445
446 static inline void cgw_unregister_filter(struct net *net, struct cgw_job *gwj)
447 {
448 can_rx_unregister(net, gwj->src.dev, gwj->ccgw.filter.can_id,
449 gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj);
450 }
451
452 static int cgw_notifier(struct notifier_block *nb,
453 unsigned long msg, void *ptr)
454 {
455 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
456 struct net *net = dev_net(dev);
457
458 if (dev->type != ARPHRD_CAN)
459 return NOTIFY_DONE;
460
461 if (msg == NETDEV_UNREGISTER) {
462
463 struct cgw_job *gwj = NULL;
464 struct hlist_node *nx;
465
466 ASSERT_RTNL();
467
468 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
469
470 if (gwj->src.dev == dev || gwj->dst.dev == dev) {
471 hlist_del(&gwj->list);
472 cgw_unregister_filter(net, gwj);
473 kmem_cache_free(cgw_cache, gwj);
474 }
475 }
476 }
477
478 return NOTIFY_DONE;
479 }
480
481 static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type,
482 u32 pid, u32 seq, int flags)
483 {
484 struct cgw_frame_mod mb;
485 struct rtcanmsg *rtcan;
486 struct nlmsghdr *nlh;
487
488 nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags);
489 if (!nlh)
490 return -EMSGSIZE;
491
492 rtcan = nlmsg_data(nlh);
493 rtcan->can_family = AF_CAN;
494 rtcan->gwtype = gwj->gwtype;
495 rtcan->flags = gwj->flags;
496
497 /* add statistics if available */
498
499 if (gwj->handled_frames) {
500 if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0)
501 goto cancel;
502 }
503
504 if (gwj->dropped_frames) {
505 if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0)
506 goto cancel;
507 }
508
509 if (gwj->deleted_frames) {
510 if (nla_put_u32(skb, CGW_DELETED, gwj->deleted_frames) < 0)
511 goto cancel;
512 }
513
514 /* check non default settings of attributes */
515
516 if (gwj->limit_hops) {
517 if (nla_put_u8(skb, CGW_LIM_HOPS, gwj->limit_hops) < 0)
518 goto cancel;
519 }
520
521 if (gwj->mod.modtype.and) {
522 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
523 mb.modtype = gwj->mod.modtype.and;
524 if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0)
525 goto cancel;
526 }
527
528 if (gwj->mod.modtype.or) {
529 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
530 mb.modtype = gwj->mod.modtype.or;
531 if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0)
532 goto cancel;
533 }
534
535 if (gwj->mod.modtype.xor) {
536 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
537 mb.modtype = gwj->mod.modtype.xor;
538 if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0)
539 goto cancel;
540 }
541
542 if (gwj->mod.modtype.set) {
543 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
544 mb.modtype = gwj->mod.modtype.set;
545 if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0)
546 goto cancel;
547 }
548
549 if (gwj->mod.uid) {
550 if (nla_put_u32(skb, CGW_MOD_UID, gwj->mod.uid) < 0)
551 goto cancel;
552 }
553
554 if (gwj->mod.csumfunc.crc8) {
555 if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN,
556 &gwj->mod.csum.crc8) < 0)
557 goto cancel;
558 }
559
560 if (gwj->mod.csumfunc.xor) {
561 if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN,
562 &gwj->mod.csum.xor) < 0)
563 goto cancel;
564 }
565
566 if (gwj->gwtype == CGW_TYPE_CAN_CAN) {
567
568 if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) {
569 if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter),
570 &gwj->ccgw.filter) < 0)
571 goto cancel;
572 }
573
574 if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0)
575 goto cancel;
576
577 if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0)
578 goto cancel;
579 }
580
581 nlmsg_end(skb, nlh);
582 return 0;
583
584 cancel:
585 nlmsg_cancel(skb, nlh);
586 return -EMSGSIZE;
587 }
588
589 /* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */
590 static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb)
591 {
592 struct net *net = sock_net(skb->sk);
593 struct cgw_job *gwj = NULL;
594 int idx = 0;
595 int s_idx = cb->args[0];
596
597 rcu_read_lock();
598 hlist_for_each_entry_rcu(gwj, &net->can.cgw_list, list) {
599 if (idx < s_idx)
600 goto cont;
601
602 if (cgw_put_job(skb, gwj, RTM_NEWROUTE, NETLINK_CB(cb->skb).portid,
603 cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0)
604 break;
605 cont:
606 idx++;
607 }
608 rcu_read_unlock();
609
610 cb->args[0] = idx;
611
612 return skb->len;
613 }
614
615 static const struct nla_policy cgw_policy[CGW_MAX+1] = {
616 [CGW_MOD_AND] = { .len = sizeof(struct cgw_frame_mod) },
617 [CGW_MOD_OR] = { .len = sizeof(struct cgw_frame_mod) },
618 [CGW_MOD_XOR] = { .len = sizeof(struct cgw_frame_mod) },
619 [CGW_MOD_SET] = { .len = sizeof(struct cgw_frame_mod) },
620 [CGW_CS_XOR] = { .len = sizeof(struct cgw_csum_xor) },
621 [CGW_CS_CRC8] = { .len = sizeof(struct cgw_csum_crc8) },
622 [CGW_SRC_IF] = { .type = NLA_U32 },
623 [CGW_DST_IF] = { .type = NLA_U32 },
624 [CGW_FILTER] = { .len = sizeof(struct can_filter) },
625 [CGW_LIM_HOPS] = { .type = NLA_U8 },
626 [CGW_MOD_UID] = { .type = NLA_U32 },
627 };
628
629 /* check for common and gwtype specific attributes */
630 static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
631 u8 gwtype, void *gwtypeattr, u8 *limhops)
632 {
633 struct nlattr *tb[CGW_MAX+1];
634 struct cgw_frame_mod mb;
635 int modidx = 0;
636 int err = 0;
637
638 /* initialize modification & checksum data space */
639 memset(mod, 0, sizeof(*mod));
640
641 err = nlmsg_parse(nlh, sizeof(struct rtcanmsg), tb, CGW_MAX,
642 cgw_policy, NULL);
643 if (err < 0)
644 return err;
645
646 if (tb[CGW_LIM_HOPS]) {
647 *limhops = nla_get_u8(tb[CGW_LIM_HOPS]);
648
649 if (*limhops < 1 || *limhops > max_hops)
650 return -EINVAL;
651 }
652
653 /* check for AND/OR/XOR/SET modifications */
654
655 if (tb[CGW_MOD_AND]) {
656 nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN);
657
658 canframecpy(&mod->modframe.and, &mb.cf);
659 mod->modtype.and = mb.modtype;
660
661 if (mb.modtype & CGW_MOD_ID)
662 mod->modfunc[modidx++] = mod_and_id;
663
664 if (mb.modtype & CGW_MOD_DLC)
665 mod->modfunc[modidx++] = mod_and_dlc;
666
667 if (mb.modtype & CGW_MOD_DATA)
668 mod->modfunc[modidx++] = mod_and_data;
669 }
670
671 if (tb[CGW_MOD_OR]) {
672 nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN);
673
674 canframecpy(&mod->modframe.or, &mb.cf);
675 mod->modtype.or = mb.modtype;
676
677 if (mb.modtype & CGW_MOD_ID)
678 mod->modfunc[modidx++] = mod_or_id;
679
680 if (mb.modtype & CGW_MOD_DLC)
681 mod->modfunc[modidx++] = mod_or_dlc;
682
683 if (mb.modtype & CGW_MOD_DATA)
684 mod->modfunc[modidx++] = mod_or_data;
685 }
686
687 if (tb[CGW_MOD_XOR]) {
688 nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN);
689
690 canframecpy(&mod->modframe.xor, &mb.cf);
691 mod->modtype.xor = mb.modtype;
692
693 if (mb.modtype & CGW_MOD_ID)
694 mod->modfunc[modidx++] = mod_xor_id;
695
696 if (mb.modtype & CGW_MOD_DLC)
697 mod->modfunc[modidx++] = mod_xor_dlc;
698
699 if (mb.modtype & CGW_MOD_DATA)
700 mod->modfunc[modidx++] = mod_xor_data;
701 }
702
703 if (tb[CGW_MOD_SET]) {
704 nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN);
705
706 canframecpy(&mod->modframe.set, &mb.cf);
707 mod->modtype.set = mb.modtype;
708
709 if (mb.modtype & CGW_MOD_ID)
710 mod->modfunc[modidx++] = mod_set_id;
711
712 if (mb.modtype & CGW_MOD_DLC)
713 mod->modfunc[modidx++] = mod_set_dlc;
714
715 if (mb.modtype & CGW_MOD_DATA)
716 mod->modfunc[modidx++] = mod_set_data;
717 }
718
719 /* check for checksum operations after CAN frame modifications */
720 if (modidx) {
721
722 if (tb[CGW_CS_CRC8]) {
723 struct cgw_csum_crc8 *c = nla_data(tb[CGW_CS_CRC8]);
724
725 err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
726 c->result_idx);
727 if (err)
728 return err;
729
730 nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8],
731 CGW_CS_CRC8_LEN);
732
733 /*
734 * select dedicated processing function to reduce
735 * runtime operations in receive hot path.
736 */
737 if (c->from_idx < 0 || c->to_idx < 0 ||
738 c->result_idx < 0)
739 mod->csumfunc.crc8 = cgw_csum_crc8_rel;
740 else if (c->from_idx <= c->to_idx)
741 mod->csumfunc.crc8 = cgw_csum_crc8_pos;
742 else
743 mod->csumfunc.crc8 = cgw_csum_crc8_neg;
744 }
745
746 if (tb[CGW_CS_XOR]) {
747 struct cgw_csum_xor *c = nla_data(tb[CGW_CS_XOR]);
748
749 err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
750 c->result_idx);
751 if (err)
752 return err;
753
754 nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR],
755 CGW_CS_XOR_LEN);
756
757 /*
758 * select dedicated processing function to reduce
759 * runtime operations in receive hot path.
760 */
761 if (c->from_idx < 0 || c->to_idx < 0 ||
762 c->result_idx < 0)
763 mod->csumfunc.xor = cgw_csum_xor_rel;
764 else if (c->from_idx <= c->to_idx)
765 mod->csumfunc.xor = cgw_csum_xor_pos;
766 else
767 mod->csumfunc.xor = cgw_csum_xor_neg;
768 }
769
770 if (tb[CGW_MOD_UID]) {
771 nla_memcpy(&mod->uid, tb[CGW_MOD_UID], sizeof(u32));
772 }
773 }
774
775 if (gwtype == CGW_TYPE_CAN_CAN) {
776
777 /* check CGW_TYPE_CAN_CAN specific attributes */
778
779 struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr;
780 memset(ccgw, 0, sizeof(*ccgw));
781
782 /* check for can_filter in attributes */
783 if (tb[CGW_FILTER])
784 nla_memcpy(&ccgw->filter, tb[CGW_FILTER],
785 sizeof(struct can_filter));
786
787 err = -ENODEV;
788
789 /* specifying two interfaces is mandatory */
790 if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF])
791 return err;
792
793 ccgw->src_idx = nla_get_u32(tb[CGW_SRC_IF]);
794 ccgw->dst_idx = nla_get_u32(tb[CGW_DST_IF]);
795
796 /* both indices set to 0 for flushing all routing entries */
797 if (!ccgw->src_idx && !ccgw->dst_idx)
798 return 0;
799
800 /* only one index set to 0 is an error */
801 if (!ccgw->src_idx || !ccgw->dst_idx)
802 return err;
803 }
804
805 /* add the checks for other gwtypes here */
806
807 return 0;
808 }
809
810 static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh,
811 struct netlink_ext_ack *extack)
812 {
813 struct net *net = sock_net(skb->sk);
814 struct rtcanmsg *r;
815 struct cgw_job *gwj;
816 struct cf_mod mod;
817 struct can_can_gw ccgw;
818 u8 limhops = 0;
819 int err = 0;
820
821 if (!netlink_capable(skb, CAP_NET_ADMIN))
822 return -EPERM;
823
824 if (nlmsg_len(nlh) < sizeof(*r))
825 return -EINVAL;
826
827 r = nlmsg_data(nlh);
828 if (r->can_family != AF_CAN)
829 return -EPFNOSUPPORT;
830
831 /* so far we only support CAN -> CAN routings */
832 if (r->gwtype != CGW_TYPE_CAN_CAN)
833 return -EINVAL;
834
835 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
836 if (err < 0)
837 return err;
838
839 if (mod.uid) {
840
841 ASSERT_RTNL();
842
843 /* check for updating an existing job with identical uid */
844 hlist_for_each_entry(gwj, &net->can.cgw_list, list) {
845
846 if (gwj->mod.uid != mod.uid)
847 continue;
848
849 /* interfaces & filters must be identical */
850 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
851 return -EINVAL;
852
853 /* update modifications with disabled softirq & quit */
854 local_bh_disable();
855 memcpy(&gwj->mod, &mod, sizeof(mod));
856 local_bh_enable();
857 return 0;
858 }
859 }
860
861 /* ifindex == 0 is not allowed for job creation */
862 if (!ccgw.src_idx || !ccgw.dst_idx)
863 return -ENODEV;
864
865 gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL);
866 if (!gwj)
867 return -ENOMEM;
868
869 gwj->handled_frames = 0;
870 gwj->dropped_frames = 0;
871 gwj->deleted_frames = 0;
872 gwj->flags = r->flags;
873 gwj->gwtype = r->gwtype;
874 gwj->limit_hops = limhops;
875
876 /* insert already parsed information */
877 memcpy(&gwj->mod, &mod, sizeof(mod));
878 memcpy(&gwj->ccgw, &ccgw, sizeof(ccgw));
879
880 err = -ENODEV;
881
882 gwj->src.dev = __dev_get_by_index(net, gwj->ccgw.src_idx);
883
884 if (!gwj->src.dev)
885 goto out;
886
887 if (gwj->src.dev->type != ARPHRD_CAN)
888 goto out;
889
890 gwj->dst.dev = __dev_get_by_index(net, gwj->ccgw.dst_idx);
891
892 if (!gwj->dst.dev)
893 goto out;
894
895 if (gwj->dst.dev->type != ARPHRD_CAN)
896 goto out;
897
898 ASSERT_RTNL();
899
900 err = cgw_register_filter(net, gwj);
901 if (!err)
902 hlist_add_head_rcu(&gwj->list, &net->can.cgw_list);
903 out:
904 if (err)
905 kmem_cache_free(cgw_cache, gwj);
906
907 return err;
908 }
909
910 static void cgw_remove_all_jobs(struct net *net)
911 {
912 struct cgw_job *gwj = NULL;
913 struct hlist_node *nx;
914
915 ASSERT_RTNL();
916
917 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
918 hlist_del(&gwj->list);
919 cgw_unregister_filter(net, gwj);
920 kmem_cache_free(cgw_cache, gwj);
921 }
922 }
923
924 static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh,
925 struct netlink_ext_ack *extack)
926 {
927 struct net *net = sock_net(skb->sk);
928 struct cgw_job *gwj = NULL;
929 struct hlist_node *nx;
930 struct rtcanmsg *r;
931 struct cf_mod mod;
932 struct can_can_gw ccgw;
933 u8 limhops = 0;
934 int err = 0;
935
936 if (!netlink_capable(skb, CAP_NET_ADMIN))
937 return -EPERM;
938
939 if (nlmsg_len(nlh) < sizeof(*r))
940 return -EINVAL;
941
942 r = nlmsg_data(nlh);
943 if (r->can_family != AF_CAN)
944 return -EPFNOSUPPORT;
945
946 /* so far we only support CAN -> CAN routings */
947 if (r->gwtype != CGW_TYPE_CAN_CAN)
948 return -EINVAL;
949
950 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
951 if (err < 0)
952 return err;
953
954 /* two interface indices both set to 0 => remove all entries */
955 if (!ccgw.src_idx && !ccgw.dst_idx) {
956 cgw_remove_all_jobs(net);
957 return 0;
958 }
959
960 err = -EINVAL;
961
962 ASSERT_RTNL();
963
964 /* remove only the first matching entry */
965 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
966
967 if (gwj->flags != r->flags)
968 continue;
969
970 if (gwj->limit_hops != limhops)
971 continue;
972
973 /* we have a match when uid is enabled and identical */
974 if (gwj->mod.uid || mod.uid) {
975 if (gwj->mod.uid != mod.uid)
976 continue;
977 } else {
978 /* no uid => check for identical modifications */
979 if (memcmp(&gwj->mod, &mod, sizeof(mod)))
980 continue;
981 }
982
983 /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */
984 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
985 continue;
986
987 hlist_del(&gwj->list);
988 cgw_unregister_filter(net, gwj);
989 kmem_cache_free(cgw_cache, gwj);
990 err = 0;
991 break;
992 }
993
994 return err;
995 }
996
997 static int __net_init cangw_pernet_init(struct net *net)
998 {
999 INIT_HLIST_HEAD(&net->can.cgw_list);
1000 return 0;
1001 }
1002
1003 static void __net_exit cangw_pernet_exit(struct net *net)
1004 {
1005 rtnl_lock();
1006 cgw_remove_all_jobs(net);
1007 rtnl_unlock();
1008 }
1009
1010 static struct pernet_operations cangw_pernet_ops = {
1011 .init = cangw_pernet_init,
1012 .exit = cangw_pernet_exit,
1013 };
1014
1015 static __init int cgw_module_init(void)
1016 {
1017 /* sanitize given module parameter */
1018 max_hops = clamp_t(unsigned int, max_hops, CGW_MIN_HOPS, CGW_MAX_HOPS);
1019
1020 pr_info("can: netlink gateway (rev " CAN_GW_VERSION ") max_hops=%d\n",
1021 max_hops);
1022
1023 register_pernet_subsys(&cangw_pernet_ops);
1024 cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job),
1025 0, 0, NULL);
1026
1027 if (!cgw_cache)
1028 return -ENOMEM;
1029
1030 /* set notifier */
1031 notifier.notifier_call = cgw_notifier;
1032 register_netdevice_notifier(&notifier);
1033
1034 if (__rtnl_register(PF_CAN, RTM_GETROUTE, NULL, cgw_dump_jobs, NULL)) {
1035 unregister_netdevice_notifier(&notifier);
1036 kmem_cache_destroy(cgw_cache);
1037 return -ENOBUFS;
1038 }
1039
1040 /* Only the first call to __rtnl_register can fail */
1041 __rtnl_register(PF_CAN, RTM_NEWROUTE, cgw_create_job, NULL, NULL);
1042 __rtnl_register(PF_CAN, RTM_DELROUTE, cgw_remove_job, NULL, NULL);
1043
1044 return 0;
1045 }
1046
1047 static __exit void cgw_module_exit(void)
1048 {
1049 rtnl_unregister_all(PF_CAN);
1050
1051 unregister_netdevice_notifier(&notifier);
1052
1053 unregister_pernet_subsys(&cangw_pernet_ops);
1054 rcu_barrier(); /* Wait for completion of call_rcu()'s */
1055
1056 kmem_cache_destroy(cgw_cache);
1057 }
1058
1059 module_init(cgw_module_init);
1060 module_exit(cgw_module_exit);
Linux with added FPC-III support