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can: rework skb reserved data handling
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / can / gw.c
CommitLineData
c1aabdf3
OH		 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 *
c1aabdf3
OH		 40 */
41
42#include <linux/module.h>
43#include <linux/init.h>
44#include <linux/types.h>
be286baf 45#include <linux/kernel.h>
c1aabdf3
OH		 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>
d904d3ed 56#include <linux/can/skb.h>
c1aabdf3
OH		 57#include <linux/can/gw.h>
58#include <net/rtnetlink.h>
59#include <net/net_namespace.h>
60#include <net/sock.h>
61
be286baf
OH		 62#define CAN_GW_VERSION "20130117"
63#define CAN_GW_NAME "can-gw"
c1aabdf3
OH		 64
65MODULE_DESCRIPTION("PF_CAN netlink gateway");
66MODULE_LICENSE("Dual BSD/GPL");
67MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
be286baf
OH		 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) ")");
c1aabdf3 81
a75afd47 82static HLIST_HEAD(cgw_list);
c1aabdf3
OH		 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};
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 */
122struct 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 */
129struct cgw_job {
130 struct hlist_node list;
131 struct rcu_head rcu;
132 u32 handled_frames;
133 u32 dropped_frames;
e6afa00a 134 u32 deleted_frames;
c1aabdf3
OH		 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 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
157MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id)
158MODFUNC(mod_and_dlc, cf->can_dlc &= mod->modframe.and.can_dlc)
159MODFUNC(mod_and_data, *(u64 *)cf->data &= *(u64 *)mod->modframe.and.data)
160MODFUNC(mod_or_id, cf->can_id |= mod->modframe.or.can_id)
161MODFUNC(mod_or_dlc, cf->can_dlc |= mod->modframe.or.can_dlc)
162MODFUNC(mod_or_data, *(u64 *)cf->data |= *(u64 *)mod->modframe.or.data)
163MODFUNC(mod_xor_id, cf->can_id ^= mod->modframe.xor.can_id)
164MODFUNC(mod_xor_dlc, cf->can_dlc ^= mod->modframe.xor.can_dlc)
165MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data)
166MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id)
167MODFUNC(mod_set_dlc, cf->can_dlc = mod->modframe.set.can_dlc)
168MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data)
169
170static 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
183static 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
202static 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
210static 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
232static 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
243static 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
254static 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
293static 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
320static 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 */
348static 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
be286baf
OH		 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/unsued 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
e6afa00a
OH		 371 if (cgw_hops(skb) >= max_hops) {
372 /* indicate deleted frames due to misconfiguration */
373 gwj->deleted_frames++;
c1aabdf3 374 return;
e6afa00a 375 }
c1aabdf3
OH		 376
377 if (!(gwj->dst.dev->flags & IFF_UP)) {
378 gwj->dropped_frames++;
379 return;
380 }
381
d904d3ed
OH		 382 /* is sending the skb back to the incoming interface not allowed? */
383 if (!(gwj->flags & CGW_FLAGS_CAN_IIF_TX_OK) &&
2bf3440d 384 can_skb_prv(skb)->ifindex == gwj->dst.dev->ifindex)
d904d3ed
OH		 385 return;
386
c1aabdf3
OH		 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
be286baf
OH		 403 /* put the incremented hop counter in the cloned skb */
404 cgw_hops(nskb) = cgw_hops(skb) + 1;
c1aabdf3
OH		 405 nskb->dev = gwj->dst.dev;
406
407 /* pointer to modifiable CAN frame */
408 cf = (struct can_frame *)nskb->data;
409
410 /* perform preprocessed modification functions if there are any */
411 while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx])
412 (*gwj->mod.modfunc[modidx++])(cf, &gwj->mod);
413
414 /* check for checksum updates when the CAN frame has been modified */
415 if (modidx) {
416 if (gwj->mod.csumfunc.crc8)
417 (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8);
418
419 if (gwj->mod.csumfunc.xor)
420 (*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor);
421 }
422
423 /* clear the skb timestamp if not configured the other way */
424 if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP))
425 nskb->tstamp.tv64 = 0;
426
427 /* send to netdevice */
428 if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO))
429 gwj->dropped_frames++;
430 else
431 gwj->handled_frames++;
432}
433
434static inline int cgw_register_filter(struct cgw_job *gwj)
435{
436 return can_rx_register(gwj->src.dev, gwj->ccgw.filter.can_id,
437 gwj->ccgw.filter.can_mask, can_can_gw_rcv,
438 gwj, "gw");
439}
440
441static inline void cgw_unregister_filter(struct cgw_job *gwj)
442{
443 can_rx_unregister(gwj->src.dev, gwj->ccgw.filter.can_id,
444 gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj);
445}
446
447static int cgw_notifier(struct notifier_block *nb,
448 unsigned long msg, void *data)
449{
450 struct net_device *dev = (struct net_device *)data;
451
452 if (!net_eq(dev_net(dev), &init_net))
453 return NOTIFY_DONE;
454 if (dev->type != ARPHRD_CAN)
455 return NOTIFY_DONE;
456
457 if (msg == NETDEV_UNREGISTER) {
458
459 struct cgw_job *gwj = NULL;
460 struct hlist_node *n, *nx;
461
462 ASSERT_RTNL();
463
464 hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
465
466 if (gwj->src.dev == dev || gwj->dst.dev == dev) {
467 hlist_del(&gwj->list);
468 cgw_unregister_filter(gwj);
469 kfree(gwj);
470 }
471 }
472 }
473
474 return NOTIFY_DONE;
475}
476
1da0faa3
TG		 477static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type,
478 u32 pid, u32 seq, int flags)
c1aabdf3
OH		 479{
480 struct cgw_frame_mod mb;
481 struct rtcanmsg *rtcan;
1da0faa3
TG		 482 struct nlmsghdr *nlh;
483
484 nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags);
c1aabdf3
OH		 485 if (!nlh)
486 return -EMSGSIZE;
487
488 rtcan = nlmsg_data(nlh);
489 rtcan->can_family = AF_CAN;
490 rtcan->gwtype = gwj->gwtype;
491 rtcan->flags = gwj->flags;
492
493 /* add statistics if available */
494
495 if (gwj->handled_frames) {
496 if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0)
497 goto cancel;
c1aabdf3
OH		 498 }
499
500 if (gwj->dropped_frames) {
501 if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0)
502 goto cancel;
c1aabdf3
OH		 503 }
504
e6afa00a
OH		 505 if (gwj->deleted_frames) {
506 if (nla_put_u32(skb, CGW_DELETED, gwj->deleted_frames) < 0)
507 goto cancel;
508 }
509
c1aabdf3
OH		 510 /* check non default settings of attributes */
511
512 if (gwj->mod.modtype.and) {
513 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
514 mb.modtype = gwj->mod.modtype.and;
515 if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0)
516 goto cancel;
c1aabdf3
OH		 517 }
518
519 if (gwj->mod.modtype.or) {
520 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
521 mb.modtype = gwj->mod.modtype.or;
522 if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0)
523 goto cancel;
c1aabdf3
OH		 524 }
525
526 if (gwj->mod.modtype.xor) {
527 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
528 mb.modtype = gwj->mod.modtype.xor;
529 if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0)
530 goto cancel;
c1aabdf3
OH		 531 }
532
533 if (gwj->mod.modtype.set) {
534 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
535 mb.modtype = gwj->mod.modtype.set;
536 if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0)
537 goto cancel;
c1aabdf3
OH		 538 }
539
540 if (gwj->mod.csumfunc.crc8) {
541 if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN,
542 &gwj->mod.csum.crc8) < 0)
543 goto cancel;
c1aabdf3
OH		 544 }
545
546 if (gwj->mod.csumfunc.xor) {
547 if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN,
548 &gwj->mod.csum.xor) < 0)
549 goto cancel;
c1aabdf3
OH		 550 }
551
552 if (gwj->gwtype == CGW_TYPE_CAN_CAN) {
553
554 if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) {
555 if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter),
556 &gwj->ccgw.filter) < 0)
557 goto cancel;
c1aabdf3
OH		 558 }
559
560 if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0)
561 goto cancel;
c1aabdf3
OH		 562
563 if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0)
564 goto cancel;
c1aabdf3
OH		 565 }
566
6eaf53ca 567 return nlmsg_end(skb, nlh);
c1aabdf3
OH		 568
569cancel:
570 nlmsg_cancel(skb, nlh);
571 return -EMSGSIZE;
572}
573
574/* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */
575static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb)
576{
577 struct cgw_job *gwj = NULL;
578 struct hlist_node *n;
579 int idx = 0;
580 int s_idx = cb->args[0];
581
582 rcu_read_lock();
583 hlist_for_each_entry_rcu(gwj, n, &cgw_list, list) {
584 if (idx < s_idx)
585 goto cont;
586
15e47304 587 if (cgw_put_job(skb, gwj, RTM_NEWROUTE, NETLINK_CB(cb->skb).portid,
1da0faa3 588 cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0)
c1aabdf3
OH		 589 break;
590cont:
591 idx++;
592 }
593 rcu_read_unlock();
594
595 cb->args[0] = idx;
596
597 return skb->len;
598}
599
732d35fd
TG		 600static const struct nla_policy cgw_policy[CGW_MAX+1] = {
601 [CGW_MOD_AND] = { .len = sizeof(struct cgw_frame_mod) },
602 [CGW_MOD_OR] = { .len = sizeof(struct cgw_frame_mod) },
603 [CGW_MOD_XOR] = { .len = sizeof(struct cgw_frame_mod) },
604 [CGW_MOD_SET] = { .len = sizeof(struct cgw_frame_mod) },
605 [CGW_CS_XOR] = { .len = sizeof(struct cgw_csum_xor) },
606 [CGW_CS_CRC8] = { .len = sizeof(struct cgw_csum_crc8) },
607 [CGW_SRC_IF] = { .type = NLA_U32 },
608 [CGW_DST_IF] = { .type = NLA_U32 },
609 [CGW_FILTER] = { .len = sizeof(struct can_filter) },
610};
611
c1aabdf3
OH		 612/* check for common and gwtype specific attributes */
613static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
614 u8 gwtype, void *gwtypeattr)
615{
616 struct nlattr *tb[CGW_MAX+1];
617 struct cgw_frame_mod mb;
618 int modidx = 0;
619 int err = 0;
620
621 /* initialize modification & checksum data space */
622 memset(mod, 0, sizeof(*mod));
623
732d35fd
TG		 624 err = nlmsg_parse(nlh, sizeof(struct rtcanmsg), tb, CGW_MAX,
625 cgw_policy);
c1aabdf3
OH		 626 if (err < 0)
627 return err;
628
629 /* check for AND/OR/XOR/SET modifications */
630
732d35fd 631 if (tb[CGW_MOD_AND]) {
c1aabdf3
OH		 632 nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN);
633
634 canframecpy(&mod->modframe.and, &mb.cf);
635 mod->modtype.and = mb.modtype;
636
637 if (mb.modtype & CGW_MOD_ID)
638 mod->modfunc[modidx++] = mod_and_id;
639
640 if (mb.modtype & CGW_MOD_DLC)
641 mod->modfunc[modidx++] = mod_and_dlc;
642
643 if (mb.modtype & CGW_MOD_DATA)
644 mod->modfunc[modidx++] = mod_and_data;
645 }
646
732d35fd 647 if (tb[CGW_MOD_OR]) {
c1aabdf3
OH		 648 nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN);
649
650 canframecpy(&mod->modframe.or, &mb.cf);
651 mod->modtype.or = mb.modtype;
652
653 if (mb.modtype & CGW_MOD_ID)
654 mod->modfunc[modidx++] = mod_or_id;
655
656 if (mb.modtype & CGW_MOD_DLC)
657 mod->modfunc[modidx++] = mod_or_dlc;
658
659 if (mb.modtype & CGW_MOD_DATA)
660 mod->modfunc[modidx++] = mod_or_data;
661 }
662
732d35fd 663 if (tb[CGW_MOD_XOR]) {
c1aabdf3
OH		 664 nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN);
665
666 canframecpy(&mod->modframe.xor, &mb.cf);
667 mod->modtype.xor = mb.modtype;
668
669 if (mb.modtype & CGW_MOD_ID)
670 mod->modfunc[modidx++] = mod_xor_id;
671
672 if (mb.modtype & CGW_MOD_DLC)
673 mod->modfunc[modidx++] = mod_xor_dlc;
674
675 if (mb.modtype & CGW_MOD_DATA)
676 mod->modfunc[modidx++] = mod_xor_data;
677 }
678
732d35fd 679 if (tb[CGW_MOD_SET]) {
c1aabdf3
OH		 680 nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN);
681
682 canframecpy(&mod->modframe.set, &mb.cf);
683 mod->modtype.set = mb.modtype;
684
685 if (mb.modtype & CGW_MOD_ID)
686 mod->modfunc[modidx++] = mod_set_id;
687
688 if (mb.modtype & CGW_MOD_DLC)
689 mod->modfunc[modidx++] = mod_set_dlc;
690
691 if (mb.modtype & CGW_MOD_DATA)
692 mod->modfunc[modidx++] = mod_set_data;
693 }
694
695 /* check for checksum operations after CAN frame modifications */
696 if (modidx) {
697
732d35fd 698 if (tb[CGW_CS_CRC8]) {
5d91efa8 699 struct cgw_csum_crc8 *c = nla_data(tb[CGW_CS_CRC8]);
c1aabdf3
OH		 700
701 err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
702 c->result_idx);
703 if (err)
704 return err;
705
706 nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8],
707 CGW_CS_CRC8_LEN);
708
709 /*
710 * select dedicated processing function to reduce
711 * runtime operations in receive hot path.
712 */
713 if (c->from_idx < 0 || c->to_idx < 0 ||
714 c->result_idx < 0)
715 mod->csumfunc.crc8 = cgw_csum_crc8_rel;
716 else if (c->from_idx <= c->to_idx)
717 mod->csumfunc.crc8 = cgw_csum_crc8_pos;
718 else
719 mod->csumfunc.crc8 = cgw_csum_crc8_neg;
720 }
721
732d35fd 722 if (tb[CGW_CS_XOR]) {
5d91efa8 723 struct cgw_csum_xor *c = nla_data(tb[CGW_CS_XOR]);
c1aabdf3
OH		 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.xor, tb[CGW_CS_XOR],
731 CGW_CS_XOR_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.xor = cgw_csum_xor_rel;
740 else if (c->from_idx <= c->to_idx)
741 mod->csumfunc.xor = cgw_csum_xor_pos;
742 else
743 mod->csumfunc.xor = cgw_csum_xor_neg;
744 }
745 }
746
747 if (gwtype == CGW_TYPE_CAN_CAN) {
748
749 /* check CGW_TYPE_CAN_CAN specific attributes */
750
751 struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr;
752 memset(ccgw, 0, sizeof(*ccgw));
753
754 /* check for can_filter in attributes */
732d35fd 755 if (tb[CGW_FILTER])
c1aabdf3
OH		 756 nla_memcpy(&ccgw->filter, tb[CGW_FILTER],
757 sizeof(struct can_filter));
758
759 err = -ENODEV;
760
761 /* specifying two interfaces is mandatory */
762 if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF])
763 return err;
764
732d35fd
TG		 765 ccgw->src_idx = nla_get_u32(tb[CGW_SRC_IF]);
766 ccgw->dst_idx = nla_get_u32(tb[CGW_DST_IF]);
c1aabdf3
OH		 767
768 /* both indices set to 0 for flushing all routing entries */
769 if (!ccgw->src_idx && !ccgw->dst_idx)
770 return 0;
771
772 /* only one index set to 0 is an error */
773 if (!ccgw->src_idx || !ccgw->dst_idx)
774 return err;
775 }
776
777 /* add the checks for other gwtypes here */
778
779 return 0;
780}
781
782static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh,
783 void *arg)
784{
785 struct rtcanmsg *r;
786 struct cgw_job *gwj;
787 int err = 0;
788
dfc47ef8
EB		 789 if (!capable(CAP_NET_ADMIN))
790 return -EPERM;
791
c1aabdf3
OH		 792 if (nlmsg_len(nlh) < sizeof(*r))
793 return -EINVAL;
794
795 r = nlmsg_data(nlh);
796 if (r->can_family != AF_CAN)
797 return -EPFNOSUPPORT;
798
799 /* so far we only support CAN -> CAN routings */
800 if (r->gwtype != CGW_TYPE_CAN_CAN)
801 return -EINVAL;
802
803 gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL);
804 if (!gwj)
805 return -ENOMEM;
806
807 gwj->handled_frames = 0;
808 gwj->dropped_frames = 0;
e6afa00a 809 gwj->deleted_frames = 0;
c1aabdf3
OH		 810 gwj->flags = r->flags;
811 gwj->gwtype = r->gwtype;
812
813 err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw);
814 if (err < 0)
815 goto out;
816
817 err = -ENODEV;
818
819 /* ifindex == 0 is not allowed for job creation */
820 if (!gwj->ccgw.src_idx || !gwj->ccgw.dst_idx)
821 goto out;
822
823 gwj->src.dev = dev_get_by_index(&init_net, gwj->ccgw.src_idx);
824
825 if (!gwj->src.dev)
826 goto out;
827
828 /* check for CAN netdev not using header_ops - see gw_rcv() */
829 if (gwj->src.dev->type != ARPHRD_CAN || gwj->src.dev->header_ops)
830 goto put_src_out;
831
832 gwj->dst.dev = dev_get_by_index(&init_net, gwj->ccgw.dst_idx);
833
834 if (!gwj->dst.dev)
835 goto put_src_out;
836
837 /* check for CAN netdev not using header_ops - see gw_rcv() */
838 if (gwj->dst.dev->type != ARPHRD_CAN || gwj->dst.dev->header_ops)
839 goto put_src_dst_out;
840
841 ASSERT_RTNL();
842
843 err = cgw_register_filter(gwj);
844 if (!err)
845 hlist_add_head_rcu(&gwj->list, &cgw_list);
846
847put_src_dst_out:
848 dev_put(gwj->dst.dev);
849put_src_out:
850 dev_put(gwj->src.dev);
851out:
852 if (err)
853 kmem_cache_free(cgw_cache, gwj);
854
855 return err;
856}
857
858static void cgw_remove_all_jobs(void)
859{
860 struct cgw_job *gwj = NULL;
861 struct hlist_node *n, *nx;
862
863 ASSERT_RTNL();
864
865 hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
866 hlist_del(&gwj->list);
867 cgw_unregister_filter(gwj);
868 kfree(gwj);
869 }
870}
871
872static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
873{
874 struct cgw_job *gwj = NULL;
875 struct hlist_node *n, *nx;
876 struct rtcanmsg *r;
877 struct cf_mod mod;
878 struct can_can_gw ccgw;
879 int err = 0;
880
dfc47ef8
EB		 881 if (!capable(CAP_NET_ADMIN))
882 return -EPERM;
883
c1aabdf3
OH		 884 if (nlmsg_len(nlh) < sizeof(*r))
885 return -EINVAL;
886
887 r = nlmsg_data(nlh);
888 if (r->can_family != AF_CAN)
889 return -EPFNOSUPPORT;
890
891 /* so far we only support CAN -> CAN routings */
892 if (r->gwtype != CGW_TYPE_CAN_CAN)
893 return -EINVAL;
894
895 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw);
896 if (err < 0)
897 return err;
898
899 /* two interface indices both set to 0 => remove all entries */
900 if (!ccgw.src_idx && !ccgw.dst_idx) {
901 cgw_remove_all_jobs();
902 return 0;
903 }
904
905 err = -EINVAL;
906
907 ASSERT_RTNL();
908
909 /* remove only the first matching entry */
910 hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
911
912 if (gwj->flags != r->flags)
913 continue;
914
915 if (memcmp(&gwj->mod, &mod, sizeof(mod)))
916 continue;
917
918 /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */
919 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
920 continue;
921
922 hlist_del(&gwj->list);
923 cgw_unregister_filter(gwj);
924 kfree(gwj);
925 err = 0;
926 break;
927 }
928
929 return err;
930}
931
932static __init int cgw_module_init(void)
933{
be286baf
OH		 934 /* sanitize given module parameter */
935 max_hops = clamp_t(unsigned int, max_hops, CGW_MIN_HOPS, CGW_MAX_HOPS);
936
937 pr_info("can: netlink gateway (rev " CAN_GW_VERSION ") max_hops=%d\n",
938 max_hops);
c1aabdf3
OH		 939
940 cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job),
941 0, 0, NULL);
942
943 if (!cgw_cache)
944 return -ENOMEM;
945
946 /* set notifier */
947 notifier.notifier_call = cgw_notifier;
948 register_netdevice_notifier(&notifier);
949
950 if (__rtnl_register(PF_CAN, RTM_GETROUTE, NULL, cgw_dump_jobs, NULL)) {
951 unregister_netdevice_notifier(&notifier);
952 kmem_cache_destroy(cgw_cache);
953 return -ENOBUFS;
954 }
955
956 /* Only the first call to __rtnl_register can fail */
957 __rtnl_register(PF_CAN, RTM_NEWROUTE, cgw_create_job, NULL, NULL);
958 __rtnl_register(PF_CAN, RTM_DELROUTE, cgw_remove_job, NULL, NULL);
959
960 return 0;
961}
962
963static __exit void cgw_module_exit(void)
964{
965 rtnl_unregister_all(PF_CAN);
966
967 unregister_netdevice_notifier(&notifier);
968
969 rtnl_lock();
970 cgw_remove_all_jobs();
971 rtnl_unlock();
972
973 rcu_barrier(); /* Wait for completion of call_rcu()'s */
974
975 kmem_cache_destroy(cgw_cache);
976}
977
978module_init(cgw_module_init);
979module_exit(cgw_module_exit);
kernel source for telekom puls (alcatel/mediatek)