xref: /linux/net/can/gw.c (revision b58c4649d94eebb1257e0716e4e948dcaa4ae5b5)
1  // SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
2  /* gw.c - CAN frame Gateway/Router/Bridge with netlink interface
3   *
4   * Copyright (c) 2019 Volkswagen Group Electronic Research
5   * All rights reserved.
6   *
7   * Redistribution and use in source and binary forms, with or without
8   * modification, are permitted provided that the following conditions
9   * are met:
10   * 1. Redistributions of source code must retain the above copyright
11   *    notice, this list of conditions and the following disclaimer.
12   * 2. Redistributions in binary form must reproduce the above copyright
13   *    notice, this list of conditions and the following disclaimer in the
14   *    documentation and/or other materials provided with the distribution.
15   * 3. Neither the name of Volkswagen nor the names of its contributors
16   *    may be used to endorse or promote products derived from this software
17   *    without specific prior written permission.
18   *
19   * Alternatively, provided that this notice is retained in full, this
20   * software may be distributed under the terms of the GNU General
21   * Public License ("GPL") version 2, in which case the provisions of the
22   * GPL apply INSTEAD OF those given above.
23   *
24   * The provided data structures and external interfaces from this code
25   * are not restricted to be used by modules with a GPL compatible license.
26   *
27   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
29   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
30   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
31   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
32   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
33   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
37   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
38   * DAMAGE.
39   *
40   */
41  
42  #include <linux/module.h>
43  #include <linux/init.h>
44  #include <linux/types.h>
45  #include <linux/kernel.h>
46  #include <linux/list.h>
47  #include <linux/spinlock.h>
48  #include <linux/rcupdate.h>
49  #include <linux/rculist.h>
50  #include <linux/net.h>
51  #include <linux/netdevice.h>
52  #include <linux/if_arp.h>
53  #include <linux/skbuff.h>
54  #include <linux/can.h>
55  #include <linux/can/core.h>
56  #include <linux/can/skb.h>
57  #include <linux/can/gw.h>
58  #include <net/rtnetlink.h>
59  #include <net/net_namespace.h>
60  #include <net/sock.h>
61  
62  #define CAN_GW_NAME "can-gw"
63  
64  MODULE_DESCRIPTION("PF_CAN netlink gateway");
65  MODULE_LICENSE("Dual BSD/GPL");
66  MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
67  MODULE_ALIAS(CAN_GW_NAME);
68  
69  #define CGW_MIN_HOPS 1
70  #define CGW_MAX_HOPS 6
71  #define CGW_DEFAULT_HOPS 1
72  
73  static unsigned int max_hops __read_mostly = CGW_DEFAULT_HOPS;
74  module_param(max_hops, uint, 0444);
75  MODULE_PARM_DESC(max_hops,
76  		 "maximum " CAN_GW_NAME " routing hops for CAN frames "
77  		 "(valid values: " __stringify(CGW_MIN_HOPS) "-"
78  		 __stringify(CGW_MAX_HOPS) " hops, "
79  		 "default: " __stringify(CGW_DEFAULT_HOPS) ")");
80  
81  static struct notifier_block notifier;
82  static struct kmem_cache *cgw_cache __read_mostly;
83  
84  /* structure that contains the (on-the-fly) CAN frame modifications */
85  struct cf_mod {
86  	struct {
87  		struct canfd_frame and;
88  		struct canfd_frame or;
89  		struct canfd_frame xor;
90  		struct canfd_frame set;
91  	} modframe;
92  	struct {
93  		u8 and;
94  		u8 or;
95  		u8 xor;
96  		u8 set;
97  	} modtype;
98  	void (*modfunc[MAX_MODFUNCTIONS])(struct canfd_frame *cf,
99  					  struct cf_mod *mod);
100  
101  	/* CAN frame checksum calculation after CAN frame modifications */
102  	struct {
103  		struct cgw_csum_xor xor;
104  		struct cgw_csum_crc8 crc8;
105  	} csum;
106  	struct {
107  		void (*xor)(struct canfd_frame *cf,
108  			    struct cgw_csum_xor *xor);
109  		void (*crc8)(struct canfd_frame *cf,
110  			     struct cgw_csum_crc8 *crc8);
111  	} csumfunc;
112  	u32 uid;
113  };
114  
115  /* So far we just support CAN -> CAN routing and frame modifications.
116   *
117   * The internal can_can_gw structure contains data and attributes for
118   * a CAN -> CAN gateway job.
119   */
120  struct can_can_gw {
121  	struct can_filter filter;
122  	int src_idx;
123  	int dst_idx;
124  };
125  
126  /* list entry for CAN gateways jobs */
127  struct cgw_job {
128  	struct hlist_node list;
129  	struct rcu_head rcu;
130  	u32 handled_frames;
131  	u32 dropped_frames;
132  	u32 deleted_frames;
133  	struct cf_mod mod;
134  	union {
135  		/* CAN frame data source */
136  		struct net_device *dev;
137  	} src;
138  	union {
139  		/* CAN frame data destination */
140  		struct net_device *dev;
141  	} dst;
142  	union {
143  		struct can_can_gw ccgw;
144  		/* tbc */
145  	};
146  	u8 gwtype;
147  	u8 limit_hops;
148  	u16 flags;
149  };
150  
151  /* modification functions that are invoked in the hot path in can_can_gw_rcv */
152  
153  #define MODFUNC(func, op) static void func(struct canfd_frame *cf, \
154  					   struct cf_mod *mod) { op ; }
155  
156  MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id)
157  MODFUNC(mod_and_len, cf->len &= mod->modframe.and.len)
158  MODFUNC(mod_and_flags, cf->flags &= mod->modframe.and.flags)
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_len, cf->len |= mod->modframe.or.len)
162  MODFUNC(mod_or_flags, cf->flags |= mod->modframe.or.flags)
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_len, cf->len ^= mod->modframe.xor.len)
166  MODFUNC(mod_xor_flags, cf->flags ^= mod->modframe.xor.flags)
167  MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data)
168  MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id)
169  MODFUNC(mod_set_len, cf->len = mod->modframe.set.len)
170  MODFUNC(mod_set_flags, cf->flags = mod->modframe.set.flags)
171  MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data)
172  
173  static void mod_and_fddata(struct canfd_frame *cf, struct cf_mod *mod)
174  {
175  	int i;
176  
177  	for (i = 0; i < CANFD_MAX_DLEN; i += 8)
178  		*(u64 *)(cf->data + i) &= *(u64 *)(mod->modframe.and.data + i);
179  }
180  
181  static void mod_or_fddata(struct canfd_frame *cf, struct cf_mod *mod)
182  {
183  	int i;
184  
185  	for (i = 0; i < CANFD_MAX_DLEN; i += 8)
186  		*(u64 *)(cf->data + i) |= *(u64 *)(mod->modframe.or.data + i);
187  }
188  
189  static void mod_xor_fddata(struct canfd_frame *cf, struct cf_mod *mod)
190  {
191  	int i;
192  
193  	for (i = 0; i < CANFD_MAX_DLEN; i += 8)
194  		*(u64 *)(cf->data + i) ^= *(u64 *)(mod->modframe.xor.data + i);
195  }
196  
197  static void mod_set_fddata(struct canfd_frame *cf, struct cf_mod *mod)
198  {
199  	memcpy(cf->data, mod->modframe.set.data, CANFD_MAX_DLEN);
200  }
201  
202  /* retrieve valid CC DLC value and store it into 'len' */
203  static void mod_retrieve_ccdlc(struct canfd_frame *cf)
204  {
205  	struct can_frame *ccf = (struct can_frame *)cf;
206  
207  	/* len8_dlc is only valid if len == CAN_MAX_DLEN */
208  	if (ccf->len != CAN_MAX_DLEN)
209  		return;
210  
211  	/* do we have a valid len8_dlc value from 9 .. 15 ? */
212  	if (ccf->len8_dlc > CAN_MAX_DLEN && ccf->len8_dlc <= CAN_MAX_RAW_DLC)
213  		ccf->len = ccf->len8_dlc;
214  }
215  
216  /* convert valid CC DLC value in 'len' into struct can_frame elements */
217  static void mod_store_ccdlc(struct canfd_frame *cf)
218  {
219  	struct can_frame *ccf = (struct can_frame *)cf;
220  
221  	/* clear potential leftovers */
222  	ccf->len8_dlc = 0;
223  
224  	/* plain data length 0 .. 8 - that was easy */
225  	if (ccf->len <= CAN_MAX_DLEN)
226  		return;
227  
228  	/* potentially broken values are caught in can_can_gw_rcv() */
229  	if (ccf->len > CAN_MAX_RAW_DLC)
230  		return;
231  
232  	/* we have a valid dlc value from 9 .. 15 in ccf->len */
233  	ccf->len8_dlc = ccf->len;
234  	ccf->len = CAN_MAX_DLEN;
235  }
236  
237  static void mod_and_ccdlc(struct canfd_frame *cf, struct cf_mod *mod)
238  {
239  	mod_retrieve_ccdlc(cf);
240  	mod_and_len(cf, mod);
241  	mod_store_ccdlc(cf);
242  }
243  
244  static void mod_or_ccdlc(struct canfd_frame *cf, struct cf_mod *mod)
245  {
246  	mod_retrieve_ccdlc(cf);
247  	mod_or_len(cf, mod);
248  	mod_store_ccdlc(cf);
249  }
250  
251  static void mod_xor_ccdlc(struct canfd_frame *cf, struct cf_mod *mod)
252  {
253  	mod_retrieve_ccdlc(cf);
254  	mod_xor_len(cf, mod);
255  	mod_store_ccdlc(cf);
256  }
257  
258  static void mod_set_ccdlc(struct canfd_frame *cf, struct cf_mod *mod)
259  {
260  	mod_set_len(cf, mod);
261  	mod_store_ccdlc(cf);
262  }
263  
264  static void canframecpy(struct canfd_frame *dst, struct can_frame *src)
265  {
266  	/* Copy the struct members separately to ensure that no uninitialized
267  	 * data are copied in the 3 bytes hole of the struct. This is needed
268  	 * to make easy compares of the data in the struct cf_mod.
269  	 */
270  
271  	dst->can_id = src->can_id;
272  	dst->len = src->len;
273  	*(u64 *)dst->data = *(u64 *)src->data;
274  }
275  
276  static void canfdframecpy(struct canfd_frame *dst, struct canfd_frame *src)
277  {
278  	/* Copy the struct members separately to ensure that no uninitialized
279  	 * data are copied in the 2 bytes hole of the struct. This is needed
280  	 * to make easy compares of the data in the struct cf_mod.
281  	 */
282  
283  	dst->can_id = src->can_id;
284  	dst->flags = src->flags;
285  	dst->len = src->len;
286  	memcpy(dst->data, src->data, CANFD_MAX_DLEN);
287  }
288  
289  static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re, struct rtcanmsg *r)
290  {
291  	s8 dlen = CAN_MAX_DLEN;
292  
293  	if (r->flags & CGW_FLAGS_CAN_FD)
294  		dlen = CANFD_MAX_DLEN;
295  
296  	/* absolute dlc values 0 .. 7 => 0 .. 7, e.g. data [0]
297  	 * relative to received dlc -1 .. -8 :
298  	 * e.g. for received dlc = 8
299  	 * -1 => index = 7 (data[7])
300  	 * -3 => index = 5 (data[5])
301  	 * -8 => index = 0 (data[0])
302  	 */
303  
304  	if (fr >= -dlen && fr < dlen &&
305  	    to >= -dlen && to < dlen &&
306  	    re >= -dlen && re < dlen)
307  		return 0;
308  	else
309  		return -EINVAL;
310  }
311  
312  static inline int calc_idx(int idx, int rx_len)
313  {
314  	if (idx < 0)
315  		return rx_len + idx;
316  	else
317  		return idx;
318  }
319  
320  static void cgw_csum_xor_rel(struct canfd_frame *cf, struct cgw_csum_xor *xor)
321  {
322  	int from = calc_idx(xor->from_idx, cf->len);
323  	int to = calc_idx(xor->to_idx, cf->len);
324  	int res = calc_idx(xor->result_idx, cf->len);
325  	u8 val = xor->init_xor_val;
326  	int i;
327  
328  	if (from < 0 || to < 0 || res < 0)
329  		return;
330  
331  	if (from <= to) {
332  		for (i = from; i <= to; i++)
333  			val ^= cf->data[i];
334  	} else {
335  		for (i = from; i >= to; i--)
336  			val ^= cf->data[i];
337  	}
338  
339  	cf->data[res] = val;
340  }
341  
342  static void cgw_csum_xor_pos(struct canfd_frame *cf, struct cgw_csum_xor *xor)
343  {
344  	u8 val = xor->init_xor_val;
345  	int i;
346  
347  	for (i = xor->from_idx; i <= xor->to_idx; i++)
348  		val ^= cf->data[i];
349  
350  	cf->data[xor->result_idx] = val;
351  }
352  
353  static void cgw_csum_xor_neg(struct canfd_frame *cf, struct cgw_csum_xor *xor)
354  {
355  	u8 val = xor->init_xor_val;
356  	int i;
357  
358  	for (i = xor->from_idx; i >= xor->to_idx; i--)
359  		val ^= cf->data[i];
360  
361  	cf->data[xor->result_idx] = val;
362  }
363  
364  static void cgw_csum_crc8_rel(struct canfd_frame *cf,
365  			      struct cgw_csum_crc8 *crc8)
366  {
367  	int from = calc_idx(crc8->from_idx, cf->len);
368  	int to = calc_idx(crc8->to_idx, cf->len);
369  	int res = calc_idx(crc8->result_idx, cf->len);
370  	u8 crc = crc8->init_crc_val;
371  	int i;
372  
373  	if (from < 0 || to < 0 || res < 0)
374  		return;
375  
376  	if (from <= to) {
377  		for (i = crc8->from_idx; i <= crc8->to_idx; i++)
378  			crc = crc8->crctab[crc ^ cf->data[i]];
379  	} else {
380  		for (i = crc8->from_idx; i >= crc8->to_idx; i--)
381  			crc = crc8->crctab[crc ^ cf->data[i]];
382  	}
383  
384  	switch (crc8->profile) {
385  	case CGW_CRC8PRF_1U8:
386  		crc = crc8->crctab[crc ^ crc8->profile_data[0]];
387  		break;
388  
389  	case  CGW_CRC8PRF_16U8:
390  		crc = crc8->crctab[crc ^ crc8->profile_data[cf->data[1] & 0xF]];
391  		break;
392  
393  	case CGW_CRC8PRF_SFFID_XOR:
394  		crc = crc8->crctab[crc ^ (cf->can_id & 0xFF) ^
395  				   (cf->can_id >> 8 & 0xFF)];
396  		break;
397  	}
398  
399  	cf->data[crc8->result_idx] = crc ^ crc8->final_xor_val;
400  }
401  
402  static void cgw_csum_crc8_pos(struct canfd_frame *cf,
403  			      struct cgw_csum_crc8 *crc8)
404  {
405  	u8 crc = crc8->init_crc_val;
406  	int i;
407  
408  	for (i = crc8->from_idx; i <= crc8->to_idx; i++)
409  		crc = crc8->crctab[crc ^ cf->data[i]];
410  
411  	switch (crc8->profile) {
412  	case CGW_CRC8PRF_1U8:
413  		crc = crc8->crctab[crc ^ crc8->profile_data[0]];
414  		break;
415  
416  	case  CGW_CRC8PRF_16U8:
417  		crc = crc8->crctab[crc ^ crc8->profile_data[cf->data[1] & 0xF]];
418  		break;
419  
420  	case CGW_CRC8PRF_SFFID_XOR:
421  		crc = crc8->crctab[crc ^ (cf->can_id & 0xFF) ^
422  				   (cf->can_id >> 8 & 0xFF)];
423  		break;
424  	}
425  
426  	cf->data[crc8->result_idx] = crc ^ crc8->final_xor_val;
427  }
428  
429  static void cgw_csum_crc8_neg(struct canfd_frame *cf,
430  			      struct cgw_csum_crc8 *crc8)
431  {
432  	u8 crc = crc8->init_crc_val;
433  	int i;
434  
435  	for (i = crc8->from_idx; i >= crc8->to_idx; i--)
436  		crc = crc8->crctab[crc ^ cf->data[i]];
437  
438  	switch (crc8->profile) {
439  	case CGW_CRC8PRF_1U8:
440  		crc = crc8->crctab[crc ^ crc8->profile_data[0]];
441  		break;
442  
443  	case  CGW_CRC8PRF_16U8:
444  		crc = crc8->crctab[crc ^ crc8->profile_data[cf->data[1] & 0xF]];
445  		break;
446  
447  	case CGW_CRC8PRF_SFFID_XOR:
448  		crc = crc8->crctab[crc ^ (cf->can_id & 0xFF) ^
449  				   (cf->can_id >> 8 & 0xFF)];
450  		break;
451  	}
452  
453  	cf->data[crc8->result_idx] = crc ^ crc8->final_xor_val;
454  }
455  
456  /* the receive & process & send function */
457  static void can_can_gw_rcv(struct sk_buff *skb, void *data)
458  {
459  	struct cgw_job *gwj = (struct cgw_job *)data;
460  	struct canfd_frame *cf;
461  	struct sk_buff *nskb;
462  	int modidx = 0;
463  
464  	/* process strictly Classic CAN or CAN FD frames */
465  	if (gwj->flags & CGW_FLAGS_CAN_FD) {
466  		if (skb->len != CANFD_MTU)
467  			return;
468  	} else {
469  		if (skb->len != CAN_MTU)
470  			return;
471  	}
472  
473  	/* Do not handle CAN frames routed more than 'max_hops' times.
474  	 * In general we should never catch this delimiter which is intended
475  	 * to cover a misconfiguration protection (e.g. circular CAN routes).
476  	 *
477  	 * The Controller Area Network controllers only accept CAN frames with
478  	 * correct CRCs - which are not visible in the controller registers.
479  	 * According to skbuff.h documentation the csum_start element for IP
480  	 * checksums is undefined/unused when ip_summed == CHECKSUM_UNNECESSARY.
481  	 * Only CAN skbs can be processed here which already have this property.
482  	 */
483  
484  #define cgw_hops(skb) ((skb)->csum_start)
485  
486  	BUG_ON(skb->ip_summed != CHECKSUM_UNNECESSARY);
487  
488  	if (cgw_hops(skb) >= max_hops) {
489  		/* indicate deleted frames due to misconfiguration */
490  		gwj->deleted_frames++;
491  		return;
492  	}
493  
494  	if (!(gwj->dst.dev->flags & IFF_UP)) {
495  		gwj->dropped_frames++;
496  		return;
497  	}
498  
499  	/* is sending the skb back to the incoming interface not allowed? */
500  	if (!(gwj->flags & CGW_FLAGS_CAN_IIF_TX_OK) &&
501  	    can_skb_prv(skb)->ifindex == gwj->dst.dev->ifindex)
502  		return;
503  
504  	/* clone the given skb, which has not been done in can_rcv()
505  	 *
506  	 * When there is at least one modification function activated,
507  	 * we need to copy the skb as we want to modify skb->data.
508  	 */
509  	if (gwj->mod.modfunc[0])
510  		nskb = skb_copy(skb, GFP_ATOMIC);
511  	else
512  		nskb = skb_clone(skb, GFP_ATOMIC);
513  
514  	if (!nskb) {
515  		gwj->dropped_frames++;
516  		return;
517  	}
518  
519  	/* put the incremented hop counter in the cloned skb */
520  	cgw_hops(nskb) = cgw_hops(skb) + 1;
521  
522  	/* first processing of this CAN frame -> adjust to private hop limit */
523  	if (gwj->limit_hops && cgw_hops(nskb) == 1)
524  		cgw_hops(nskb) = max_hops - gwj->limit_hops + 1;
525  
526  	nskb->dev = gwj->dst.dev;
527  
528  	/* pointer to modifiable CAN frame */
529  	cf = (struct canfd_frame *)nskb->data;
530  
531  	/* perform preprocessed modification functions if there are any */
532  	while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx])
533  		(*gwj->mod.modfunc[modidx++])(cf, &gwj->mod);
534  
535  	/* Has the CAN frame been modified? */
536  	if (modidx) {
537  		/* get available space for the processed CAN frame type */
538  		int max_len = nskb->len - offsetof(struct canfd_frame, data);
539  
540  		/* dlc may have changed, make sure it fits to the CAN frame */
541  		if (cf->len > max_len) {
542  			/* delete frame due to misconfiguration */
543  			gwj->deleted_frames++;
544  			kfree_skb(nskb);
545  			return;
546  		}
547  
548  		/* check for checksum updates */
549  		if (gwj->mod.csumfunc.crc8)
550  			(*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8);
551  
552  		if (gwj->mod.csumfunc.xor)
553  			(*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor);
554  	}
555  
556  	/* clear the skb timestamp if not configured the other way */
557  	if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP))
558  		nskb->tstamp = 0;
559  
560  	/* send to netdevice */
561  	if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO))
562  		gwj->dropped_frames++;
563  	else
564  		gwj->handled_frames++;
565  }
566  
567  static inline int cgw_register_filter(struct net *net, struct cgw_job *gwj)
568  {
569  	return can_rx_register(net, gwj->src.dev, gwj->ccgw.filter.can_id,
570  			       gwj->ccgw.filter.can_mask, can_can_gw_rcv,
571  			       gwj, "gw", NULL);
572  }
573  
574  static inline void cgw_unregister_filter(struct net *net, struct cgw_job *gwj)
575  {
576  	can_rx_unregister(net, gwj->src.dev, gwj->ccgw.filter.can_id,
577  			  gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj);
578  }
579  
580  static int cgw_notifier(struct notifier_block *nb,
581  			unsigned long msg, void *ptr)
582  {
583  	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
584  	struct net *net = dev_net(dev);
585  
586  	if (dev->type != ARPHRD_CAN)
587  		return NOTIFY_DONE;
588  
589  	if (msg == NETDEV_UNREGISTER) {
590  		struct cgw_job *gwj = NULL;
591  		struct hlist_node *nx;
592  
593  		ASSERT_RTNL();
594  
595  		hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
596  			if (gwj->src.dev == dev || gwj->dst.dev == dev) {
597  				hlist_del(&gwj->list);
598  				cgw_unregister_filter(net, gwj);
599  				kmem_cache_free(cgw_cache, gwj);
600  			}
601  		}
602  	}
603  
604  	return NOTIFY_DONE;
605  }
606  
607  static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type,
608  		       u32 pid, u32 seq, int flags)
609  {
610  	struct rtcanmsg *rtcan;
611  	struct nlmsghdr *nlh;
612  
613  	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags);
614  	if (!nlh)
615  		return -EMSGSIZE;
616  
617  	rtcan = nlmsg_data(nlh);
618  	rtcan->can_family = AF_CAN;
619  	rtcan->gwtype = gwj->gwtype;
620  	rtcan->flags = gwj->flags;
621  
622  	/* add statistics if available */
623  
624  	if (gwj->handled_frames) {
625  		if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0)
626  			goto cancel;
627  	}
628  
629  	if (gwj->dropped_frames) {
630  		if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0)
631  			goto cancel;
632  	}
633  
634  	if (gwj->deleted_frames) {
635  		if (nla_put_u32(skb, CGW_DELETED, gwj->deleted_frames) < 0)
636  			goto cancel;
637  	}
638  
639  	/* check non default settings of attributes */
640  
641  	if (gwj->limit_hops) {
642  		if (nla_put_u8(skb, CGW_LIM_HOPS, gwj->limit_hops) < 0)
643  			goto cancel;
644  	}
645  
646  	if (gwj->flags & CGW_FLAGS_CAN_FD) {
647  		struct cgw_fdframe_mod mb;
648  
649  		if (gwj->mod.modtype.and) {
650  			memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
651  			mb.modtype = gwj->mod.modtype.and;
652  			if (nla_put(skb, CGW_FDMOD_AND, sizeof(mb), &mb) < 0)
653  				goto cancel;
654  		}
655  
656  		if (gwj->mod.modtype.or) {
657  			memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
658  			mb.modtype = gwj->mod.modtype.or;
659  			if (nla_put(skb, CGW_FDMOD_OR, sizeof(mb), &mb) < 0)
660  				goto cancel;
661  		}
662  
663  		if (gwj->mod.modtype.xor) {
664  			memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
665  			mb.modtype = gwj->mod.modtype.xor;
666  			if (nla_put(skb, CGW_FDMOD_XOR, sizeof(mb), &mb) < 0)
667  				goto cancel;
668  		}
669  
670  		if (gwj->mod.modtype.set) {
671  			memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
672  			mb.modtype = gwj->mod.modtype.set;
673  			if (nla_put(skb, CGW_FDMOD_SET, sizeof(mb), &mb) < 0)
674  				goto cancel;
675  		}
676  	} else {
677  		struct cgw_frame_mod mb;
678  
679  		if (gwj->mod.modtype.and) {
680  			memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
681  			mb.modtype = gwj->mod.modtype.and;
682  			if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0)
683  				goto cancel;
684  		}
685  
686  		if (gwj->mod.modtype.or) {
687  			memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
688  			mb.modtype = gwj->mod.modtype.or;
689  			if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0)
690  				goto cancel;
691  		}
692  
693  		if (gwj->mod.modtype.xor) {
694  			memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
695  			mb.modtype = gwj->mod.modtype.xor;
696  			if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0)
697  				goto cancel;
698  		}
699  
700  		if (gwj->mod.modtype.set) {
701  			memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
702  			mb.modtype = gwj->mod.modtype.set;
703  			if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0)
704  				goto cancel;
705  		}
706  	}
707  
708  	if (gwj->mod.uid) {
709  		if (nla_put_u32(skb, CGW_MOD_UID, gwj->mod.uid) < 0)
710  			goto cancel;
711  	}
712  
713  	if (gwj->mod.csumfunc.crc8) {
714  		if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN,
715  			    &gwj->mod.csum.crc8) < 0)
716  			goto cancel;
717  	}
718  
719  	if (gwj->mod.csumfunc.xor) {
720  		if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN,
721  			    &gwj->mod.csum.xor) < 0)
722  			goto cancel;
723  	}
724  
725  	if (gwj->gwtype == CGW_TYPE_CAN_CAN) {
726  		if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) {
727  			if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter),
728  				    &gwj->ccgw.filter) < 0)
729  				goto cancel;
730  		}
731  
732  		if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0)
733  			goto cancel;
734  
735  		if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0)
736  			goto cancel;
737  	}
738  
739  	nlmsg_end(skb, nlh);
740  	return 0;
741  
742  cancel:
743  	nlmsg_cancel(skb, nlh);
744  	return -EMSGSIZE;
745  }
746  
747  /* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */
748  static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb)
749  {
750  	struct net *net = sock_net(skb->sk);
751  	struct cgw_job *gwj = NULL;
752  	int idx = 0;
753  	int s_idx = cb->args[0];
754  
755  	rcu_read_lock();
756  	hlist_for_each_entry_rcu(gwj, &net->can.cgw_list, list) {
757  		if (idx < s_idx)
758  			goto cont;
759  
760  		if (cgw_put_job(skb, gwj, RTM_NEWROUTE,
761  				NETLINK_CB(cb->skb).portid,
762  				cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0)
763  			break;
764  cont:
765  		idx++;
766  	}
767  	rcu_read_unlock();
768  
769  	cb->args[0] = idx;
770  
771  	return skb->len;
772  }
773  
774  static const struct nla_policy cgw_policy[CGW_MAX + 1] = {
775  	[CGW_MOD_AND]	= { .len = sizeof(struct cgw_frame_mod) },
776  	[CGW_MOD_OR]	= { .len = sizeof(struct cgw_frame_mod) },
777  	[CGW_MOD_XOR]	= { .len = sizeof(struct cgw_frame_mod) },
778  	[CGW_MOD_SET]	= { .len = sizeof(struct cgw_frame_mod) },
779  	[CGW_CS_XOR]	= { .len = sizeof(struct cgw_csum_xor) },
780  	[CGW_CS_CRC8]	= { .len = sizeof(struct cgw_csum_crc8) },
781  	[CGW_SRC_IF]	= { .type = NLA_U32 },
782  	[CGW_DST_IF]	= { .type = NLA_U32 },
783  	[CGW_FILTER]	= { .len = sizeof(struct can_filter) },
784  	[CGW_LIM_HOPS]	= { .type = NLA_U8 },
785  	[CGW_MOD_UID]	= { .type = NLA_U32 },
786  	[CGW_FDMOD_AND]	= { .len = sizeof(struct cgw_fdframe_mod) },
787  	[CGW_FDMOD_OR]	= { .len = sizeof(struct cgw_fdframe_mod) },
788  	[CGW_FDMOD_XOR]	= { .len = sizeof(struct cgw_fdframe_mod) },
789  	[CGW_FDMOD_SET]	= { .len = sizeof(struct cgw_fdframe_mod) },
790  };
791  
792  /* check for common and gwtype specific attributes */
793  static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
794  			  u8 gwtype, void *gwtypeattr, u8 *limhops)
795  {
796  	struct nlattr *tb[CGW_MAX + 1];
797  	struct rtcanmsg *r = nlmsg_data(nlh);
798  	int modidx = 0;
799  	int err = 0;
800  
801  	/* initialize modification & checksum data space */
802  	memset(mod, 0, sizeof(*mod));
803  
804  	err = nlmsg_parse_deprecated(nlh, sizeof(struct rtcanmsg), tb,
805  				     CGW_MAX, cgw_policy, NULL);
806  	if (err < 0)
807  		return err;
808  
809  	if (tb[CGW_LIM_HOPS]) {
810  		*limhops = nla_get_u8(tb[CGW_LIM_HOPS]);
811  
812  		if (*limhops < 1 || *limhops > max_hops)
813  			return -EINVAL;
814  	}
815  
816  	/* check for AND/OR/XOR/SET modifications */
817  	if (r->flags & CGW_FLAGS_CAN_FD) {
818  		struct cgw_fdframe_mod mb;
819  
820  		if (tb[CGW_FDMOD_AND]) {
821  			nla_memcpy(&mb, tb[CGW_FDMOD_AND], CGW_FDMODATTR_LEN);
822  
823  			canfdframecpy(&mod->modframe.and, &mb.cf);
824  			mod->modtype.and = mb.modtype;
825  
826  			if (mb.modtype & CGW_MOD_ID)
827  				mod->modfunc[modidx++] = mod_and_id;
828  
829  			if (mb.modtype & CGW_MOD_LEN)
830  				mod->modfunc[modidx++] = mod_and_len;
831  
832  			if (mb.modtype & CGW_MOD_FLAGS)
833  				mod->modfunc[modidx++] = mod_and_flags;
834  
835  			if (mb.modtype & CGW_MOD_DATA)
836  				mod->modfunc[modidx++] = mod_and_fddata;
837  		}
838  
839  		if (tb[CGW_FDMOD_OR]) {
840  			nla_memcpy(&mb, tb[CGW_FDMOD_OR], CGW_FDMODATTR_LEN);
841  
842  			canfdframecpy(&mod->modframe.or, &mb.cf);
843  			mod->modtype.or = mb.modtype;
844  
845  			if (mb.modtype & CGW_MOD_ID)
846  				mod->modfunc[modidx++] = mod_or_id;
847  
848  			if (mb.modtype & CGW_MOD_LEN)
849  				mod->modfunc[modidx++] = mod_or_len;
850  
851  			if (mb.modtype & CGW_MOD_FLAGS)
852  				mod->modfunc[modidx++] = mod_or_flags;
853  
854  			if (mb.modtype & CGW_MOD_DATA)
855  				mod->modfunc[modidx++] = mod_or_fddata;
856  		}
857  
858  		if (tb[CGW_FDMOD_XOR]) {
859  			nla_memcpy(&mb, tb[CGW_FDMOD_XOR], CGW_FDMODATTR_LEN);
860  
861  			canfdframecpy(&mod->modframe.xor, &mb.cf);
862  			mod->modtype.xor = mb.modtype;
863  
864  			if (mb.modtype & CGW_MOD_ID)
865  				mod->modfunc[modidx++] = mod_xor_id;
866  
867  			if (mb.modtype & CGW_MOD_LEN)
868  				mod->modfunc[modidx++] = mod_xor_len;
869  
870  			if (mb.modtype & CGW_MOD_FLAGS)
871  				mod->modfunc[modidx++] = mod_xor_flags;
872  
873  			if (mb.modtype & CGW_MOD_DATA)
874  				mod->modfunc[modidx++] = mod_xor_fddata;
875  		}
876  
877  		if (tb[CGW_FDMOD_SET]) {
878  			nla_memcpy(&mb, tb[CGW_FDMOD_SET], CGW_FDMODATTR_LEN);
879  
880  			canfdframecpy(&mod->modframe.set, &mb.cf);
881  			mod->modtype.set = mb.modtype;
882  
883  			if (mb.modtype & CGW_MOD_ID)
884  				mod->modfunc[modidx++] = mod_set_id;
885  
886  			if (mb.modtype & CGW_MOD_LEN)
887  				mod->modfunc[modidx++] = mod_set_len;
888  
889  			if (mb.modtype & CGW_MOD_FLAGS)
890  				mod->modfunc[modidx++] = mod_set_flags;
891  
892  			if (mb.modtype & CGW_MOD_DATA)
893  				mod->modfunc[modidx++] = mod_set_fddata;
894  		}
895  	} else {
896  		struct cgw_frame_mod mb;
897  
898  		if (tb[CGW_MOD_AND]) {
899  			nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN);
900  
901  			canframecpy(&mod->modframe.and, &mb.cf);
902  			mod->modtype.and = mb.modtype;
903  
904  			if (mb.modtype & CGW_MOD_ID)
905  				mod->modfunc[modidx++] = mod_and_id;
906  
907  			if (mb.modtype & CGW_MOD_DLC)
908  				mod->modfunc[modidx++] = mod_and_ccdlc;
909  
910  			if (mb.modtype & CGW_MOD_DATA)
911  				mod->modfunc[modidx++] = mod_and_data;
912  		}
913  
914  		if (tb[CGW_MOD_OR]) {
915  			nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN);
916  
917  			canframecpy(&mod->modframe.or, &mb.cf);
918  			mod->modtype.or = mb.modtype;
919  
920  			if (mb.modtype & CGW_MOD_ID)
921  				mod->modfunc[modidx++] = mod_or_id;
922  
923  			if (mb.modtype & CGW_MOD_DLC)
924  				mod->modfunc[modidx++] = mod_or_ccdlc;
925  
926  			if (mb.modtype & CGW_MOD_DATA)
927  				mod->modfunc[modidx++] = mod_or_data;
928  		}
929  
930  		if (tb[CGW_MOD_XOR]) {
931  			nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN);
932  
933  			canframecpy(&mod->modframe.xor, &mb.cf);
934  			mod->modtype.xor = mb.modtype;
935  
936  			if (mb.modtype & CGW_MOD_ID)
937  				mod->modfunc[modidx++] = mod_xor_id;
938  
939  			if (mb.modtype & CGW_MOD_DLC)
940  				mod->modfunc[modidx++] = mod_xor_ccdlc;
941  
942  			if (mb.modtype & CGW_MOD_DATA)
943  				mod->modfunc[modidx++] = mod_xor_data;
944  		}
945  
946  		if (tb[CGW_MOD_SET]) {
947  			nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN);
948  
949  			canframecpy(&mod->modframe.set, &mb.cf);
950  			mod->modtype.set = mb.modtype;
951  
952  			if (mb.modtype & CGW_MOD_ID)
953  				mod->modfunc[modidx++] = mod_set_id;
954  
955  			if (mb.modtype & CGW_MOD_DLC)
956  				mod->modfunc[modidx++] = mod_set_ccdlc;
957  
958  			if (mb.modtype & CGW_MOD_DATA)
959  				mod->modfunc[modidx++] = mod_set_data;
960  		}
961  	}
962  
963  	/* check for checksum operations after CAN frame modifications */
964  	if (modidx) {
965  		if (tb[CGW_CS_CRC8]) {
966  			struct cgw_csum_crc8 *c = nla_data(tb[CGW_CS_CRC8]);
967  
968  			err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
969  						 c->result_idx, r);
970  			if (err)
971  				return err;
972  
973  			nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8],
974  				   CGW_CS_CRC8_LEN);
975  
976  			/* select dedicated processing function to reduce
977  			 * runtime operations in receive hot path.
978  			 */
979  			if (c->from_idx < 0 || c->to_idx < 0 ||
980  			    c->result_idx < 0)
981  				mod->csumfunc.crc8 = cgw_csum_crc8_rel;
982  			else if (c->from_idx <= c->to_idx)
983  				mod->csumfunc.crc8 = cgw_csum_crc8_pos;
984  			else
985  				mod->csumfunc.crc8 = cgw_csum_crc8_neg;
986  		}
987  
988  		if (tb[CGW_CS_XOR]) {
989  			struct cgw_csum_xor *c = nla_data(tb[CGW_CS_XOR]);
990  
991  			err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
992  						 c->result_idx, r);
993  			if (err)
994  				return err;
995  
996  			nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR],
997  				   CGW_CS_XOR_LEN);
998  
999  			/* select dedicated processing function to reduce
1000  			 * runtime operations in receive hot path.
1001  			 */
1002  			if (c->from_idx < 0 || c->to_idx < 0 ||
1003  			    c->result_idx < 0)
1004  				mod->csumfunc.xor = cgw_csum_xor_rel;
1005  			else if (c->from_idx <= c->to_idx)
1006  				mod->csumfunc.xor = cgw_csum_xor_pos;
1007  			else
1008  				mod->csumfunc.xor = cgw_csum_xor_neg;
1009  		}
1010  
1011  		if (tb[CGW_MOD_UID])
1012  			nla_memcpy(&mod->uid, tb[CGW_MOD_UID], sizeof(u32));
1013  	}
1014  
1015  	if (gwtype == CGW_TYPE_CAN_CAN) {
1016  		/* check CGW_TYPE_CAN_CAN specific attributes */
1017  		struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr;
1018  
1019  		memset(ccgw, 0, sizeof(*ccgw));
1020  
1021  		/* check for can_filter in attributes */
1022  		if (tb[CGW_FILTER])
1023  			nla_memcpy(&ccgw->filter, tb[CGW_FILTER],
1024  				   sizeof(struct can_filter));
1025  
1026  		err = -ENODEV;
1027  
1028  		/* specifying two interfaces is mandatory */
1029  		if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF])
1030  			return err;
1031  
1032  		ccgw->src_idx = nla_get_u32(tb[CGW_SRC_IF]);
1033  		ccgw->dst_idx = nla_get_u32(tb[CGW_DST_IF]);
1034  
1035  		/* both indices set to 0 for flushing all routing entries */
1036  		if (!ccgw->src_idx && !ccgw->dst_idx)
1037  			return 0;
1038  
1039  		/* only one index set to 0 is an error */
1040  		if (!ccgw->src_idx || !ccgw->dst_idx)
1041  			return err;
1042  	}
1043  
1044  	/* add the checks for other gwtypes here */
1045  
1046  	return 0;
1047  }
1048  
1049  static int cgw_create_job(struct sk_buff *skb,  struct nlmsghdr *nlh,
1050  			  struct netlink_ext_ack *extack)
1051  {
1052  	struct net *net = sock_net(skb->sk);
1053  	struct rtcanmsg *r;
1054  	struct cgw_job *gwj;
1055  	struct cf_mod mod;
1056  	struct can_can_gw ccgw;
1057  	u8 limhops = 0;
1058  	int err = 0;
1059  
1060  	if (!netlink_capable(skb, CAP_NET_ADMIN))
1061  		return -EPERM;
1062  
1063  	if (nlmsg_len(nlh) < sizeof(*r))
1064  		return -EINVAL;
1065  
1066  	r = nlmsg_data(nlh);
1067  	if (r->can_family != AF_CAN)
1068  		return -EPFNOSUPPORT;
1069  
1070  	/* so far we only support CAN -> CAN routings */
1071  	if (r->gwtype != CGW_TYPE_CAN_CAN)
1072  		return -EINVAL;
1073  
1074  	err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
1075  	if (err < 0)
1076  		return err;
1077  
1078  	if (mod.uid) {
1079  		ASSERT_RTNL();
1080  
1081  		/* check for updating an existing job with identical uid */
1082  		hlist_for_each_entry(gwj, &net->can.cgw_list, list) {
1083  			if (gwj->mod.uid != mod.uid)
1084  				continue;
1085  
1086  			/* interfaces & filters must be identical */
1087  			if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
1088  				return -EINVAL;
1089  
1090  			/* update modifications with disabled softirq & quit */
1091  			local_bh_disable();
1092  			memcpy(&gwj->mod, &mod, sizeof(mod));
1093  			local_bh_enable();
1094  			return 0;
1095  		}
1096  	}
1097  
1098  	/* ifindex == 0 is not allowed for job creation */
1099  	if (!ccgw.src_idx || !ccgw.dst_idx)
1100  		return -ENODEV;
1101  
1102  	gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL);
1103  	if (!gwj)
1104  		return -ENOMEM;
1105  
1106  	gwj->handled_frames = 0;
1107  	gwj->dropped_frames = 0;
1108  	gwj->deleted_frames = 0;
1109  	gwj->flags = r->flags;
1110  	gwj->gwtype = r->gwtype;
1111  	gwj->limit_hops = limhops;
1112  
1113  	/* insert already parsed information */
1114  	memcpy(&gwj->mod, &mod, sizeof(mod));
1115  	memcpy(&gwj->ccgw, &ccgw, sizeof(ccgw));
1116  
1117  	err = -ENODEV;
1118  
1119  	gwj->src.dev = __dev_get_by_index(net, gwj->ccgw.src_idx);
1120  
1121  	if (!gwj->src.dev)
1122  		goto out;
1123  
1124  	if (gwj->src.dev->type != ARPHRD_CAN)
1125  		goto out;
1126  
1127  	gwj->dst.dev = __dev_get_by_index(net, gwj->ccgw.dst_idx);
1128  
1129  	if (!gwj->dst.dev)
1130  		goto out;
1131  
1132  	if (gwj->dst.dev->type != ARPHRD_CAN)
1133  		goto out;
1134  
1135  	ASSERT_RTNL();
1136  
1137  	err = cgw_register_filter(net, gwj);
1138  	if (!err)
1139  		hlist_add_head_rcu(&gwj->list, &net->can.cgw_list);
1140  out:
1141  	if (err)
1142  		kmem_cache_free(cgw_cache, gwj);
1143  
1144  	return err;
1145  }
1146  
1147  static void cgw_remove_all_jobs(struct net *net)
1148  {
1149  	struct cgw_job *gwj = NULL;
1150  	struct hlist_node *nx;
1151  
1152  	ASSERT_RTNL();
1153  
1154  	hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
1155  		hlist_del(&gwj->list);
1156  		cgw_unregister_filter(net, gwj);
1157  		kmem_cache_free(cgw_cache, gwj);
1158  	}
1159  }
1160  
1161  static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh,
1162  			  struct netlink_ext_ack *extack)
1163  {
1164  	struct net *net = sock_net(skb->sk);
1165  	struct cgw_job *gwj = NULL;
1166  	struct hlist_node *nx;
1167  	struct rtcanmsg *r;
1168  	struct cf_mod mod;
1169  	struct can_can_gw ccgw;
1170  	u8 limhops = 0;
1171  	int err = 0;
1172  
1173  	if (!netlink_capable(skb, CAP_NET_ADMIN))
1174  		return -EPERM;
1175  
1176  	if (nlmsg_len(nlh) < sizeof(*r))
1177  		return -EINVAL;
1178  
1179  	r = nlmsg_data(nlh);
1180  	if (r->can_family != AF_CAN)
1181  		return -EPFNOSUPPORT;
1182  
1183  	/* so far we only support CAN -> CAN routings */
1184  	if (r->gwtype != CGW_TYPE_CAN_CAN)
1185  		return -EINVAL;
1186  
1187  	err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
1188  	if (err < 0)
1189  		return err;
1190  
1191  	/* two interface indices both set to 0 => remove all entries */
1192  	if (!ccgw.src_idx && !ccgw.dst_idx) {
1193  		cgw_remove_all_jobs(net);
1194  		return 0;
1195  	}
1196  
1197  	err = -EINVAL;
1198  
1199  	ASSERT_RTNL();
1200  
1201  	/* remove only the first matching entry */
1202  	hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
1203  		if (gwj->flags != r->flags)
1204  			continue;
1205  
1206  		if (gwj->limit_hops != limhops)
1207  			continue;
1208  
1209  		/* we have a match when uid is enabled and identical */
1210  		if (gwj->mod.uid || mod.uid) {
1211  			if (gwj->mod.uid != mod.uid)
1212  				continue;
1213  		} else {
1214  			/* no uid => check for identical modifications */
1215  			if (memcmp(&gwj->mod, &mod, sizeof(mod)))
1216  				continue;
1217  		}
1218  
1219  		/* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */
1220  		if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
1221  			continue;
1222  
1223  		hlist_del(&gwj->list);
1224  		cgw_unregister_filter(net, gwj);
1225  		kmem_cache_free(cgw_cache, gwj);
1226  		err = 0;
1227  		break;
1228  	}
1229  
1230  	return err;
1231  }
1232  
1233  static int __net_init cangw_pernet_init(struct net *net)
1234  {
1235  	INIT_HLIST_HEAD(&net->can.cgw_list);
1236  	return 0;
1237  }
1238  
1239  static void __net_exit cangw_pernet_exit(struct net *net)
1240  {
1241  	rtnl_lock();
1242  	cgw_remove_all_jobs(net);
1243  	rtnl_unlock();
1244  }
1245  
1246  static struct pernet_operations cangw_pernet_ops = {
1247  	.init = cangw_pernet_init,
1248  	.exit = cangw_pernet_exit,
1249  };
1250  
1251  static __init int cgw_module_init(void)
1252  {
1253  	int ret;
1254  
1255  	/* sanitize given module parameter */
1256  	max_hops = clamp_t(unsigned int, max_hops, CGW_MIN_HOPS, CGW_MAX_HOPS);
1257  
1258  	pr_info("can: netlink gateway - max_hops=%d\n",	max_hops);
1259  
1260  	ret = register_pernet_subsys(&cangw_pernet_ops);
1261  	if (ret)
1262  		return ret;
1263  
1264  	ret = -ENOMEM;
1265  	cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job),
1266  				      0, 0, NULL);
1267  	if (!cgw_cache)
1268  		goto out_cache_create;
1269  
1270  	/* set notifier */
1271  	notifier.notifier_call = cgw_notifier;
1272  	ret = register_netdevice_notifier(&notifier);
1273  	if (ret)
1274  		goto out_register_notifier;
1275  
1276  	ret = rtnl_register_module(THIS_MODULE, PF_CAN, RTM_GETROUTE,
1277  				   NULL, cgw_dump_jobs, 0);
1278  	if (ret)
1279  		goto out_rtnl_register1;
1280  
1281  	ret = rtnl_register_module(THIS_MODULE, PF_CAN, RTM_NEWROUTE,
1282  				   cgw_create_job, NULL, 0);
1283  	if (ret)
1284  		goto out_rtnl_register2;
1285  	ret = rtnl_register_module(THIS_MODULE, PF_CAN, RTM_DELROUTE,
1286  				   cgw_remove_job, NULL, 0);
1287  	if (ret)
1288  		goto out_rtnl_register3;
1289  
1290  	return 0;
1291  
1292  out_rtnl_register3:
1293  	rtnl_unregister(PF_CAN, RTM_NEWROUTE);
1294  out_rtnl_register2:
1295  	rtnl_unregister(PF_CAN, RTM_GETROUTE);
1296  out_rtnl_register1:
1297  	unregister_netdevice_notifier(&notifier);
1298  out_register_notifier:
1299  	kmem_cache_destroy(cgw_cache);
1300  out_cache_create:
1301  	unregister_pernet_subsys(&cangw_pernet_ops);
1302  
1303  	return ret;
1304  }
1305  
1306  static __exit void cgw_module_exit(void)
1307  {
1308  	rtnl_unregister_all(PF_CAN);
1309  
1310  	unregister_netdevice_notifier(&notifier);
1311  
1312  	unregister_pernet_subsys(&cangw_pernet_ops);
1313  	rcu_barrier(); /* Wait for completion of call_rcu()'s */
1314  
1315  	kmem_cache_destroy(cgw_cache);
1316  }
1317  
1318  module_init(cgw_module_init);
1319  module_exit(cgw_module_exit);
1320