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ppp: take reference on channels netns
[linux/fpc-iii.git] / net / can / gw.c
blob050a2110d43f6b78f331b599569eaaf2d8803c24
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
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 HLIST_HEAD(cgw_list);
83 static struct notifier_block notifier;
84
85 static struct kmem_cache *cgw_cache __read_mostly;
86
87 /* structure that contains the (on-the-fly) CAN frame modifications */
88 struct 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 };
114
115
116 /*
117 * So far we just support CAN -> CAN routing and frame modifications.
118 *
119 * The internal can_can_gw structure contains data and attributes for
120 * a CAN -> CAN gateway job.
121 */
122 struct can_can_gw {
123 struct can_filter filter;
124 int src_idx;
125 int dst_idx;
126 };
127
128 /* list entry for CAN gateways jobs */
129 struct cgw_job {
130 struct hlist_node list;
131 struct rcu_head rcu;
132 u32 handled_frames;
133 u32 dropped_frames;
134 u32 deleted_frames;
135 struct cf_mod mod;
136 union {
137 /* CAN frame data source */
138 struct net_device *dev;
139 } src;
140 union {
141 /* CAN frame data destination */
142 struct net_device *dev;
143 } dst;
144 union {
145 struct can_can_gw ccgw;
146 /* tbc */
147 };
148 u8 gwtype;
149 u8 limit_hops;
150 u16 flags;
151 };
152
153 /* modification functions that are invoked in the hot path in can_can_gw_rcv */
154
155 #define MODFUNC(func, op) static void func(struct can_frame *cf, \
156 struct cf_mod *mod) { op ; }
157
158 MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id)
159 MODFUNC(mod_and_dlc, cf->can_dlc &= mod->modframe.and.can_dlc)
160 MODFUNC(mod_and_data, *(u64 *)cf->data &= *(u64 *)mod->modframe.and.data)
161 MODFUNC(mod_or_id, cf->can_id |= mod->modframe.or.can_id)
162 MODFUNC(mod_or_dlc, cf->can_dlc |= mod->modframe.or.can_dlc)
163 MODFUNC(mod_or_data, *(u64 *)cf->data |= *(u64 *)mod->modframe.or.data)
164 MODFUNC(mod_xor_id, cf->can_id ^= mod->modframe.xor.can_id)
165 MODFUNC(mod_xor_dlc, cf->can_dlc ^= mod->modframe.xor.can_dlc)
166 MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data)
167 MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id)
168 MODFUNC(mod_set_dlc, cf->can_dlc = mod->modframe.set.can_dlc)
169 MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data)
170
171 static inline void canframecpy(struct can_frame *dst, struct can_frame *src)
172 {
173 /*
174 * Copy the struct members separately to ensure that no uninitialized
175 * data are copied in the 3 bytes hole of the struct. This is needed
176 * to make easy compares of the data in the struct cf_mod.
177 */
178
179 dst->can_id = src->can_id;
180 dst->can_dlc = src->can_dlc;
181 *(u64 *)dst->data = *(u64 *)src->data;
182 }
183
184 static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re)
185 {
186 /*
187 * absolute dlc values 0 .. 7 => 0 .. 7, e.g. data [0]
188 * relative to received dlc -1 .. -8 :
189 * e.g. for received dlc = 8
190 * -1 => index = 7 (data[7])
191 * -3 => index = 5 (data[5])
192 * -8 => index = 0 (data[0])
193 */
194
195 if (fr > -9 && fr < 8 &&
196 to > -9 && to < 8 &&
197 re > -9 && re < 8)
198 return 0;
199 else
200 return -EINVAL;
201 }
202
203 static inline int calc_idx(int idx, int rx_dlc)
204 {
205 if (idx < 0)
206 return rx_dlc + idx;
207 else
208 return idx;
209 }
210
211 static void cgw_csum_xor_rel(struct can_frame *cf, struct cgw_csum_xor *xor)
212 {
213 int from = calc_idx(xor->from_idx, cf->can_dlc);
214 int to = calc_idx(xor->to_idx, cf->can_dlc);
215 int res = calc_idx(xor->result_idx, cf->can_dlc);
216 u8 val = xor->init_xor_val;
217 int i;
218
219 if (from < 0 || to < 0 || res < 0)
220 return;
221
222 if (from <= to) {
223 for (i = from; i <= to; i++)
224 val ^= cf->data[i];
225 } else {
226 for (i = from; i >= to; i--)
227 val ^= cf->data[i];
228 }
229
230 cf->data[res] = val;
231 }
232
233 static void cgw_csum_xor_pos(struct can_frame *cf, struct cgw_csum_xor *xor)
234 {
235 u8 val = xor->init_xor_val;
236 int i;
237
238 for (i = xor->from_idx; i <= xor->to_idx; i++)
239 val ^= cf->data[i];
240
241 cf->data[xor->result_idx] = val;
242 }
243
244 static void cgw_csum_xor_neg(struct can_frame *cf, struct cgw_csum_xor *xor)
245 {
246 u8 val = xor->init_xor_val;
247 int i;
248
249 for (i = xor->from_idx; i >= xor->to_idx; i--)
250 val ^= cf->data[i];
251
252 cf->data[xor->result_idx] = val;
253 }
254
255 static void cgw_csum_crc8_rel(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
256 {
257 int from = calc_idx(crc8->from_idx, cf->can_dlc);
258 int to = calc_idx(crc8->to_idx, cf->can_dlc);
259 int res = calc_idx(crc8->result_idx, cf->can_dlc);
260 u8 crc = crc8->init_crc_val;
261 int i;
262
263 if (from < 0 || to < 0 || res < 0)
264 return;
265
266 if (from <= to) {
267 for (i = crc8->from_idx; i <= crc8->to_idx; i++)
268 crc = crc8->crctab[crc^cf->data[i]];
269 } else {
270 for (i = crc8->from_idx; i >= crc8->to_idx; i--)
271 crc = crc8->crctab[crc^cf->data[i]];
272 }
273
274 switch (crc8->profile) {
275
276 case CGW_CRC8PRF_1U8:
277 crc = crc8->crctab[crc^crc8->profile_data[0]];
278 break;
279
280 case CGW_CRC8PRF_16U8:
281 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
282 break;
283
284 case CGW_CRC8PRF_SFFID_XOR:
285 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
286 (cf->can_id >> 8 & 0xFF)];
287 break;
288
289 }
290
291 cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
292 }
293
294 static void cgw_csum_crc8_pos(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
295 {
296 u8 crc = crc8->init_crc_val;
297 int i;
298
299 for (i = crc8->from_idx; i <= crc8->to_idx; i++)
300 crc = crc8->crctab[crc^cf->data[i]];
301
302 switch (crc8->profile) {
303
304 case CGW_CRC8PRF_1U8:
305 crc = crc8->crctab[crc^crc8->profile_data[0]];
306 break;
307
308 case CGW_CRC8PRF_16U8:
309 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
310 break;
311
312 case CGW_CRC8PRF_SFFID_XOR:
313 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
314 (cf->can_id >> 8 & 0xFF)];
315 break;
316 }
317
318 cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
319 }
320
321 static void cgw_csum_crc8_neg(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
322 {
323 u8 crc = crc8->init_crc_val;
324 int i;
325
326 for (i = crc8->from_idx; i >= crc8->to_idx; i--)
327 crc = crc8->crctab[crc^cf->data[i]];
328
329 switch (crc8->profile) {
330
331 case CGW_CRC8PRF_1U8:
332 crc = crc8->crctab[crc^crc8->profile_data[0]];
333 break;
334
335 case CGW_CRC8PRF_16U8:
336 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
337 break;
338
339 case CGW_CRC8PRF_SFFID_XOR:
340 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
341 (cf->can_id >> 8 & 0xFF)];
342 break;
343 }
344
345 cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
346 }
347
348 /* the receive & process & send function */
349 static void can_can_gw_rcv(struct sk_buff *skb, void *data)
350 {
351 struct cgw_job *gwj = (struct cgw_job *)data;
352 struct can_frame *cf;
353 struct sk_buff *nskb;
354 int modidx = 0;
355
356 /*
357 * Do not handle CAN frames routed more than 'max_hops' times.
358 * In general we should never catch this delimiter which is intended
359 * to cover a misconfiguration protection (e.g. circular CAN routes).
360 *
361 * The Controller Area Network controllers only accept CAN frames with
362 * correct CRCs - which are not visible in the controller registers.
363 * According to skbuff.h documentation the csum_start element for IP
364 * checksums is undefined/unsued when ip_summed == CHECKSUM_UNNECESSARY.
365 * Only CAN skbs can be processed here which already have this property.
366 */
367
368 #define cgw_hops(skb) ((skb)->csum_start)
369
370 BUG_ON(skb->ip_summed != CHECKSUM_UNNECESSARY);
371
372 if (cgw_hops(skb) >= max_hops) {
373 /* indicate deleted frames due to misconfiguration */
374 gwj->deleted_frames++;
375 return;
376 }
377
378 if (!(gwj->dst.dev->flags & IFF_UP)) {
379 gwj->dropped_frames++;
380 return;
381 }
382
383 /* is sending the skb back to the incoming interface not allowed? */
384 if (!(gwj->flags & CGW_FLAGS_CAN_IIF_TX_OK) &&
385 can_skb_prv(skb)->ifindex == gwj->dst.dev->ifindex)
386 return;
387
388 /*
389 * clone the given skb, which has not been done in can_rcv()
390 *
391 * When there is at least one modification function activated,
392 * we need to copy the skb as we want to modify skb->data.
393 */
394 if (gwj->mod.modfunc[0])
395 nskb = skb_copy(skb, GFP_ATOMIC);
396 else
397 nskb = skb_clone(skb, GFP_ATOMIC);
398
399 if (!nskb) {
400 gwj->dropped_frames++;
401 return;
402 }
403
404 /* put the incremented hop counter in the cloned skb */
405 cgw_hops(nskb) = cgw_hops(skb) + 1;
406
407 /* first processing of this CAN frame -> adjust to private hop limit */
408 if (gwj->limit_hops && cgw_hops(nskb) == 1)
409 cgw_hops(nskb) = max_hops - gwj->limit_hops + 1;
410
411 nskb->dev = gwj->dst.dev;
412
413 /* pointer to modifiable CAN frame */
414 cf = (struct can_frame *)nskb->data;
415
416 /* perform preprocessed modification functions if there are any */
417 while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx])
418 (*gwj->mod.modfunc[modidx++])(cf, &gwj->mod);
419
420 /* check for checksum updates when the CAN frame has been modified */
421 if (modidx) {
422 if (gwj->mod.csumfunc.crc8)
423 (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8);
424
425 if (gwj->mod.csumfunc.xor)
426 (*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor);
427 }
428
429 /* clear the skb timestamp if not configured the other way */
430 if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP))
431 nskb->tstamp.tv64 = 0;
432
433 /* send to netdevice */
434 if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO))
435 gwj->dropped_frames++;
436 else
437 gwj->handled_frames++;
438 }
439
440 static inline int cgw_register_filter(struct cgw_job *gwj)
441 {
442 return can_rx_register(gwj->src.dev, gwj->ccgw.filter.can_id,
443 gwj->ccgw.filter.can_mask, can_can_gw_rcv,
444 gwj, "gw");
445 }
446
447 static inline void cgw_unregister_filter(struct cgw_job *gwj)
448 {
449 can_rx_unregister(gwj->src.dev, gwj->ccgw.filter.can_id,
450 gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj);
451 }
452
453 static int cgw_notifier(struct notifier_block *nb,
454 unsigned long msg, void *ptr)
455 {
456 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
457
458 if (!net_eq(dev_net(dev), &init_net))
459 return NOTIFY_DONE;
460 if (dev->type != ARPHRD_CAN)
461 return NOTIFY_DONE;
462
463 if (msg == NETDEV_UNREGISTER) {
464
465 struct cgw_job *gwj = NULL;
466 struct hlist_node *nx;
467
468 ASSERT_RTNL();
469
470 hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) {
471
472 if (gwj->src.dev == dev || gwj->dst.dev == dev) {
473 hlist_del(&gwj->list);
474 cgw_unregister_filter(gwj);
475 kmem_cache_free(cgw_cache, gwj);
476 }
477 }
478 }
479
480 return NOTIFY_DONE;
481 }
482
483 static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type,
484 u32 pid, u32 seq, int flags)
485 {
486 struct cgw_frame_mod mb;
487 struct rtcanmsg *rtcan;
488 struct nlmsghdr *nlh;
489
490 nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags);
491 if (!nlh)
492 return -EMSGSIZE;
493
494 rtcan = nlmsg_data(nlh);
495 rtcan->can_family = AF_CAN;
496 rtcan->gwtype = gwj->gwtype;
497 rtcan->flags = gwj->flags;
498
499 /* add statistics if available */
500
501 if (gwj->handled_frames) {
502 if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0)
503 goto cancel;
504 }
505
506 if (gwj->dropped_frames) {
507 if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0)
508 goto cancel;
509 }
510
511 if (gwj->deleted_frames) {
512 if (nla_put_u32(skb, CGW_DELETED, gwj->deleted_frames) < 0)
513 goto cancel;
514 }
515
516 /* check non default settings of attributes */
517
518 if (gwj->limit_hops) {
519 if (nla_put_u8(skb, CGW_LIM_HOPS, gwj->limit_hops) < 0)
520 goto cancel;
521 }
522
523 if (gwj->mod.modtype.and) {
524 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
525 mb.modtype = gwj->mod.modtype.and;
526 if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0)
527 goto cancel;
528 }
529
530 if (gwj->mod.modtype.or) {
531 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
532 mb.modtype = gwj->mod.modtype.or;
533 if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0)
534 goto cancel;
535 }
536
537 if (gwj->mod.modtype.xor) {
538 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
539 mb.modtype = gwj->mod.modtype.xor;
540 if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0)
541 goto cancel;
542 }
543
544 if (gwj->mod.modtype.set) {
545 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
546 mb.modtype = gwj->mod.modtype.set;
547 if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0)
548 goto cancel;
549 }
550
551 if (gwj->mod.csumfunc.crc8) {
552 if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN,
553 &gwj->mod.csum.crc8) < 0)
554 goto cancel;
555 }
556
557 if (gwj->mod.csumfunc.xor) {
558 if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN,
559 &gwj->mod.csum.xor) < 0)
560 goto cancel;
561 }
562
563 if (gwj->gwtype == CGW_TYPE_CAN_CAN) {
564
565 if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) {
566 if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter),
567 &gwj->ccgw.filter) < 0)
568 goto cancel;
569 }
570
571 if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0)
572 goto cancel;
573
574 if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0)
575 goto cancel;
576 }
577
578 return nlmsg_end(skb, nlh);
579
580 cancel:
581 nlmsg_cancel(skb, nlh);
582 return -EMSGSIZE;
583 }
584
585 /* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */
586 static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb)
587 {
588 struct cgw_job *gwj = NULL;
589 int idx = 0;
590 int s_idx = cb->args[0];
591
592 rcu_read_lock();
593 hlist_for_each_entry_rcu(gwj, &cgw_list, list) {
594 if (idx < s_idx)
595 goto cont;
596
597 if (cgw_put_job(skb, gwj, RTM_NEWROUTE, NETLINK_CB(cb->skb).portid,
598 cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0)
599 break;
600 cont:
601 idx++;
602 }
603 rcu_read_unlock();
604
605 cb->args[0] = idx;
606
607 return skb->len;
608 }
609
610 static const struct nla_policy cgw_policy[CGW_MAX+1] = {
611 [CGW_MOD_AND] = { .len = sizeof(struct cgw_frame_mod) },
612 [CGW_MOD_OR] = { .len = sizeof(struct cgw_frame_mod) },
613 [CGW_MOD_XOR] = { .len = sizeof(struct cgw_frame_mod) },
614 [CGW_MOD_SET] = { .len = sizeof(struct cgw_frame_mod) },
615 [CGW_CS_XOR] = { .len = sizeof(struct cgw_csum_xor) },
616 [CGW_CS_CRC8] = { .len = sizeof(struct cgw_csum_crc8) },
617 [CGW_SRC_IF] = { .type = NLA_U32 },
618 [CGW_DST_IF] = { .type = NLA_U32 },
619 [CGW_FILTER] = { .len = sizeof(struct can_filter) },
620 [CGW_LIM_HOPS] = { .type = NLA_U8 },
621 };
622
623 /* check for common and gwtype specific attributes */
624 static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
625 u8 gwtype, void *gwtypeattr, u8 *limhops)
626 {
627 struct nlattr *tb[CGW_MAX+1];
628 struct cgw_frame_mod mb;
629 int modidx = 0;
630 int err = 0;
631
632 /* initialize modification & checksum data space */
633 memset(mod, 0, sizeof(*mod));
634
635 err = nlmsg_parse(nlh, sizeof(struct rtcanmsg), tb, CGW_MAX,
636 cgw_policy);
637 if (err < 0)
638 return err;
639
640 if (tb[CGW_LIM_HOPS]) {
641 *limhops = nla_get_u8(tb[CGW_LIM_HOPS]);
642
643 if (*limhops < 1 || *limhops > max_hops)
644 return -EINVAL;
645 }
646
647 /* check for AND/OR/XOR/SET modifications */
648
649 if (tb[CGW_MOD_AND]) {
650 nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN);
651
652 canframecpy(&mod->modframe.and, &mb.cf);
653 mod->modtype.and = mb.modtype;
654
655 if (mb.modtype & CGW_MOD_ID)
656 mod->modfunc[modidx++] = mod_and_id;
657
658 if (mb.modtype & CGW_MOD_DLC)
659 mod->modfunc[modidx++] = mod_and_dlc;
660
661 if (mb.modtype & CGW_MOD_DATA)
662 mod->modfunc[modidx++] = mod_and_data;
663 }
664
665 if (tb[CGW_MOD_OR]) {
666 nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN);
667
668 canframecpy(&mod->modframe.or, &mb.cf);
669 mod->modtype.or = mb.modtype;
670
671 if (mb.modtype & CGW_MOD_ID)
672 mod->modfunc[modidx++] = mod_or_id;
673
674 if (mb.modtype & CGW_MOD_DLC)
675 mod->modfunc[modidx++] = mod_or_dlc;
676
677 if (mb.modtype & CGW_MOD_DATA)
678 mod->modfunc[modidx++] = mod_or_data;
679 }
680
681 if (tb[CGW_MOD_XOR]) {
682 nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN);
683
684 canframecpy(&mod->modframe.xor, &mb.cf);
685 mod->modtype.xor = mb.modtype;
686
687 if (mb.modtype & CGW_MOD_ID)
688 mod->modfunc[modidx++] = mod_xor_id;
689
690 if (mb.modtype & CGW_MOD_DLC)
691 mod->modfunc[modidx++] = mod_xor_dlc;
692
693 if (mb.modtype & CGW_MOD_DATA)
694 mod->modfunc[modidx++] = mod_xor_data;
695 }
696
697 if (tb[CGW_MOD_SET]) {
698 nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN);
699
700 canframecpy(&mod->modframe.set, &mb.cf);
701 mod->modtype.set = mb.modtype;
702
703 if (mb.modtype & CGW_MOD_ID)
704 mod->modfunc[modidx++] = mod_set_id;
705
706 if (mb.modtype & CGW_MOD_DLC)
707 mod->modfunc[modidx++] = mod_set_dlc;
708
709 if (mb.modtype & CGW_MOD_DATA)
710 mod->modfunc[modidx++] = mod_set_data;
711 }
712
713 /* check for checksum operations after CAN frame modifications */
714 if (modidx) {
715
716 if (tb[CGW_CS_CRC8]) {
717 struct cgw_csum_crc8 *c = nla_data(tb[CGW_CS_CRC8]);
718
719 err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
720 c->result_idx);
721 if (err)
722 return err;
723
724 nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8],
725 CGW_CS_CRC8_LEN);
726
727 /*
728 * select dedicated processing function to reduce
729 * runtime operations in receive hot path.
730 */
731 if (c->from_idx < 0 || c->to_idx < 0 ||
732 c->result_idx < 0)
733 mod->csumfunc.crc8 = cgw_csum_crc8_rel;
734 else if (c->from_idx <= c->to_idx)
735 mod->csumfunc.crc8 = cgw_csum_crc8_pos;
736 else
737 mod->csumfunc.crc8 = cgw_csum_crc8_neg;
738 }
739
740 if (tb[CGW_CS_XOR]) {
741 struct cgw_csum_xor *c = nla_data(tb[CGW_CS_XOR]);
742
743 err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
744 c->result_idx);
745 if (err)
746 return err;
747
748 nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR],
749 CGW_CS_XOR_LEN);
750
751 /*
752 * select dedicated processing function to reduce
753 * runtime operations in receive hot path.
754 */
755 if (c->from_idx < 0 || c->to_idx < 0 ||
756 c->result_idx < 0)
757 mod->csumfunc.xor = cgw_csum_xor_rel;
758 else if (c->from_idx <= c->to_idx)
759 mod->csumfunc.xor = cgw_csum_xor_pos;
760 else
761 mod->csumfunc.xor = cgw_csum_xor_neg;
762 }
763 }
764
765 if (gwtype == CGW_TYPE_CAN_CAN) {
766
767 /* check CGW_TYPE_CAN_CAN specific attributes */
768
769 struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr;
770 memset(ccgw, 0, sizeof(*ccgw));
771
772 /* check for can_filter in attributes */
773 if (tb[CGW_FILTER])
774 nla_memcpy(&ccgw->filter, tb[CGW_FILTER],
775 sizeof(struct can_filter));
776
777 err = -ENODEV;
778
779 /* specifying two interfaces is mandatory */
780 if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF])
781 return err;
782
783 ccgw->src_idx = nla_get_u32(tb[CGW_SRC_IF]);
784 ccgw->dst_idx = nla_get_u32(tb[CGW_DST_IF]);
785
786 /* both indices set to 0 for flushing all routing entries */
787 if (!ccgw->src_idx && !ccgw->dst_idx)
788 return 0;
789
790 /* only one index set to 0 is an error */
791 if (!ccgw->src_idx || !ccgw->dst_idx)
792 return err;
793 }
794
795 /* add the checks for other gwtypes here */
796
797 return 0;
798 }
799
800 static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh)
801 {
802 struct rtcanmsg *r;
803 struct cgw_job *gwj;
804 u8 limhops = 0;
805 int err = 0;
806
807 if (!netlink_capable(skb, CAP_NET_ADMIN))
808 return -EPERM;
809
810 if (nlmsg_len(nlh) < sizeof(*r))
811 return -EINVAL;
812
813 r = nlmsg_data(nlh);
814 if (r->can_family != AF_CAN)
815 return -EPFNOSUPPORT;
816
817 /* so far we only support CAN -> CAN routings */
818 if (r->gwtype != CGW_TYPE_CAN_CAN)
819 return -EINVAL;
820
821 gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL);
822 if (!gwj)
823 return -ENOMEM;
824
825 gwj->handled_frames = 0;
826 gwj->dropped_frames = 0;
827 gwj->deleted_frames = 0;
828 gwj->flags = r->flags;
829 gwj->gwtype = r->gwtype;
830
831 err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw,
832 &limhops);
833 if (err < 0)
834 goto out;
835
836 err = -ENODEV;
837
838 /* ifindex == 0 is not allowed for job creation */
839 if (!gwj->ccgw.src_idx || !gwj->ccgw.dst_idx)
840 goto out;
841
842 gwj->src.dev = __dev_get_by_index(&init_net, gwj->ccgw.src_idx);
843
844 if (!gwj->src.dev)
845 goto out;
846
847 if (gwj->src.dev->type != ARPHRD_CAN)
848 goto out;
849
850 gwj->dst.dev = __dev_get_by_index(&init_net, gwj->ccgw.dst_idx);
851
852 if (!gwj->dst.dev)
853 goto out;
854
855 if (gwj->dst.dev->type != ARPHRD_CAN)
856 goto out;
857
858 gwj->limit_hops = limhops;
859
860 ASSERT_RTNL();
861
862 err = cgw_register_filter(gwj);
863 if (!err)
864 hlist_add_head_rcu(&gwj->list, &cgw_list);
865 out:
866 if (err)
867 kmem_cache_free(cgw_cache, gwj);
868
869 return err;
870 }
871
872 static void cgw_remove_all_jobs(void)
873 {
874 struct cgw_job *gwj = NULL;
875 struct hlist_node *nx;
876
877 ASSERT_RTNL();
878
879 hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) {
880 hlist_del(&gwj->list);
881 cgw_unregister_filter(gwj);
882 kmem_cache_free(cgw_cache, gwj);
883 }
884 }
885
886 static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh)
887 {
888 struct cgw_job *gwj = NULL;
889 struct hlist_node *nx;
890 struct rtcanmsg *r;
891 struct cf_mod mod;
892 struct can_can_gw ccgw;
893 u8 limhops = 0;
894 int err = 0;
895
896 if (!netlink_capable(skb, CAP_NET_ADMIN))
897 return -EPERM;
898
899 if (nlmsg_len(nlh) < sizeof(*r))
900 return -EINVAL;
901
902 r = nlmsg_data(nlh);
903 if (r->can_family != AF_CAN)
904 return -EPFNOSUPPORT;
905
906 /* so far we only support CAN -> CAN routings */
907 if (r->gwtype != CGW_TYPE_CAN_CAN)
908 return -EINVAL;
909
910 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
911 if (err < 0)
912 return err;
913
914 /* two interface indices both set to 0 => remove all entries */
915 if (!ccgw.src_idx && !ccgw.dst_idx) {
916 cgw_remove_all_jobs();
917 return 0;
918 }
919
920 err = -EINVAL;
921
922 ASSERT_RTNL();
923
924 /* remove only the first matching entry */
925 hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) {
926
927 if (gwj->flags != r->flags)
928 continue;
929
930 if (gwj->limit_hops != limhops)
931 continue;
932
933 if (memcmp(&gwj->mod, &mod, sizeof(mod)))
934 continue;
935
936 /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */
937 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
938 continue;
939
940 hlist_del(&gwj->list);
941 cgw_unregister_filter(gwj);
942 kmem_cache_free(cgw_cache, gwj);
943 err = 0;
944 break;
945 }
946
947 return err;
948 }
949
950 static __init int cgw_module_init(void)
951 {
952 /* sanitize given module parameter */
953 max_hops = clamp_t(unsigned int, max_hops, CGW_MIN_HOPS, CGW_MAX_HOPS);
954
955 pr_info("can: netlink gateway (rev " CAN_GW_VERSION ") max_hops=%d\n",
956 max_hops);
957
958 cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job),
959 0, 0, NULL);
960
961 if (!cgw_cache)
962 return -ENOMEM;
963
964 /* set notifier */
965 notifier.notifier_call = cgw_notifier;
966 register_netdevice_notifier(&notifier);
967
968 if (__rtnl_register(PF_CAN, RTM_GETROUTE, NULL, cgw_dump_jobs, NULL)) {
969 unregister_netdevice_notifier(&notifier);
970 kmem_cache_destroy(cgw_cache);
971 return -ENOBUFS;
972 }
973
974 /* Only the first call to __rtnl_register can fail */
975 __rtnl_register(PF_CAN, RTM_NEWROUTE, cgw_create_job, NULL, NULL);
976 __rtnl_register(PF_CAN, RTM_DELROUTE, cgw_remove_job, NULL, NULL);
977
978 return 0;
979 }
980
981 static __exit void cgw_module_exit(void)
982 {
983 rtnl_unregister_all(PF_CAN);
984
985 unregister_netdevice_notifier(&notifier);
986
987 rtnl_lock();
988 cgw_remove_all_jobs();
989 rtnl_unlock();
990
991 rcu_barrier(); /* Wait for completion of call_rcu()'s */
992
993 kmem_cache_destroy(cgw_cache);
994 }
995
996 module_init(cgw_module_init);
997 module_exit(cgw_module_exit);
Linux with added FPC-III support