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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 = 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", NULL);
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);