1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/jhash.h>
3 #include <linux/netfilter.h>
4 #include <linux/rcupdate.h>
5 #include <linux/rhashtable.h>
6 #include <linux/vmalloc.h>
7 #include <net/genetlink.h>
8 #include <net/netns/generic.h>
9 #include <uapi/linux/genetlink.h>
10 #include "ila.h"
11
12 struct ila_xlat_params {
13 struct ila_params ip;
14 int ifindex;
15 };
16
17 struct ila_map {
18 struct ila_xlat_params xp;
19 struct rhash_head node;
20 struct ila_map __rcu *next;
21 struct rcu_head rcu;
22 };
23
24 #define MAX_LOCKS 1024
25 #define LOCKS_PER_CPU 10
26
27 static int alloc_ila_locks(struct ila_net *ilan)
28 {
29 return alloc_bucket_spinlocks(&ilan->xlat.locks, &ilan->xlat.locks_mask,
30 MAX_LOCKS, LOCKS_PER_CPU,
31 GFP_KERNEL);
32 }
33
34 static u32 hashrnd __read_mostly;
35 static __always_inline void __ila_hash_secret_init(void)
36 {
37 net_get_random_once(&hashrnd, sizeof(hashrnd));
38 }
39
40 static inline u32 ila_locator_hash(struct ila_locator loc)
41 {
42 u32 *v = (u32 *)loc.v32;
43
44 __ila_hash_secret_init();
45 return jhash_2words(v[0], v[1], hashrnd);
46 }
47
48 static inline spinlock_t *ila_get_lock(struct ila_net *ilan,
49 struct ila_locator loc)
50 {
51 return &ilan->xlat.locks[ila_locator_hash(loc) & ilan->xlat.locks_mask];
52 }
53
54 static inline int ila_cmp_wildcards(struct ila_map *ila,
55 struct ila_addr *iaddr, int ifindex)
56 {
57 return (ila->xp.ifindex && ila->xp.ifindex != ifindex);
58 }
59
60 static inline int ila_cmp_params(struct ila_map *ila,
61 struct ila_xlat_params *xp)
62 {
63 return (ila->xp.ifindex != xp->ifindex);
64 }
65
66 static int ila_cmpfn(struct rhashtable_compare_arg *arg,
67 const void *obj)
68 {
69 const struct ila_map *ila = obj;
70
71 return (ila->xp.ip.locator_match.v64 != *(__be64 *)arg->key);
72 }
73
74 static inline int ila_order(struct ila_map *ila)
75 {
76 int score = 0;
77
78 if (ila->xp.ifindex)
79 score += 1 << 1;
80
81 return score;
82 }
83
84 static const struct rhashtable_params rht_params = {
85 .nelem_hint = 1024,
86 .head_offset = offsetof(struct ila_map, node),
87 .key_offset = offsetof(struct ila_map, xp.ip.locator_match),
88 .key_len = sizeof(u64), /* identifier */
89 .max_size = 1048576,
90 .min_size = 256,
91 .automatic_shrinking = true,
92 .obj_cmpfn = ila_cmpfn,
93 };
94
95 static int parse_nl_config(struct genl_info *info,
96 struct ila_xlat_params *xp)
97 {
98 memset(xp, 0, sizeof(*xp));
99
100 if (info->attrs[ILA_ATTR_LOCATOR])
101 xp->ip.locator.v64 = (__force __be64)nla_get_u64(
102 info->attrs[ILA_ATTR_LOCATOR]);
103
104 if (info->attrs[ILA_ATTR_LOCATOR_MATCH])
105 xp->ip.locator_match.v64 = (__force __be64)nla_get_u64(
106 info->attrs[ILA_ATTR_LOCATOR_MATCH]);
107
108 if (info->attrs[ILA_ATTR_CSUM_MODE])
109 xp->ip.csum_mode = nla_get_u8(info->attrs[ILA_ATTR_CSUM_MODE]);
110 else
111 xp->ip.csum_mode = ILA_CSUM_NO_ACTION;
112
113 if (info->attrs[ILA_ATTR_IDENT_TYPE])
114 xp->ip.ident_type = nla_get_u8(
115 info->attrs[ILA_ATTR_IDENT_TYPE]);
116 else
117 xp->ip.ident_type = ILA_ATYPE_USE_FORMAT;
118
119 if (info->attrs[ILA_ATTR_IFINDEX])
120 xp->ifindex = nla_get_s32(info->attrs[ILA_ATTR_IFINDEX]);
121
122 return 0;
123 }
124
125 /* Must be called with rcu readlock */
126 static inline struct ila_map *ila_lookup_wildcards(struct ila_addr *iaddr,
127 int ifindex,
128 struct ila_net *ilan)
129 {
130 struct ila_map *ila;
131
132 ila = rhashtable_lookup_fast(&ilan->xlat.rhash_table, &iaddr->loc,
133 rht_params);
134 while (ila) {
135 if (!ila_cmp_wildcards(ila, iaddr, ifindex))
136 return ila;
137 ila = rcu_access_pointer(ila->next);
138 }
139
140 return NULL;
141 }
142
143 /* Must be called with rcu readlock */
144 static inline struct ila_map *ila_lookup_by_params(struct ila_xlat_params *xp,
145 struct ila_net *ilan)
146 {
147 struct ila_map *ila;
148
149 ila = rhashtable_lookup_fast(&ilan->xlat.rhash_table,
150 &xp->ip.locator_match,
151 rht_params);
152 while (ila) {
153 if (!ila_cmp_params(ila, xp))
154 return ila;
155 ila = rcu_access_pointer(ila->next);
156 }
157
158 return NULL;
159 }
160
161 static inline void ila_release(struct ila_map *ila)
162 {
163 kfree_rcu(ila, rcu);
164 }
165
166 static void ila_free_node(struct ila_map *ila)
167 {
168 struct ila_map *next;
169
170 /* Assume rcu_readlock held */
171 while (ila) {
172 next = rcu_access_pointer(ila->next);
173 ila_release(ila);
174 ila = next;
175 }
176 }
177
178 static void ila_free_cb(void *ptr, void *arg)
179 {
180 ila_free_node((struct ila_map *)ptr);
181 }
182
183 static int ila_xlat_addr(struct sk_buff *skb, bool sir2ila);
184
185 static unsigned int
186 ila_nf_input(void *priv,
187 struct sk_buff *skb,
188 const struct nf_hook_state *state)
189 {
190 ila_xlat_addr(skb, false);
191 return NF_ACCEPT;
192 }
193
194 static const struct nf_hook_ops ila_nf_hook_ops[] = {
195 {
196 .hook = ila_nf_input,
197 .pf = NFPROTO_IPV6,
198 .hooknum = NF_INET_PRE_ROUTING,
199 .priority = -1,
200 },
201 };
202
203 static int ila_add_mapping(struct net *net, struct ila_xlat_params *xp)
204 {
205 struct ila_net *ilan = net_generic(net, ila_net_id);
206 struct ila_map *ila, *head;
207 spinlock_t *lock = ila_get_lock(ilan, xp->ip.locator_match);
208 int err = 0, order;
209
210 if (!ilan->xlat.hooks_registered) {
211 /* We defer registering net hooks in the namespace until the
212 * first mapping is added.
213 */
214 err = nf_register_net_hooks(net, ila_nf_hook_ops,
215 ARRAY_SIZE(ila_nf_hook_ops));
216 if (err)
217 return err;
218
219 ilan->xlat.hooks_registered = true;
220 }
221
222 ila = kzalloc(sizeof(*ila), GFP_KERNEL);
223 if (!ila)
224 return -ENOMEM;
225
226 ila_init_saved_csum(&xp->ip);
227
228 ila->xp = *xp;
229
230 order = ila_order(ila);
231
232 spin_lock(lock);
233
234 head = rhashtable_lookup_fast(&ilan->xlat.rhash_table,
235 &xp->ip.locator_match,
236 rht_params);
237 if (!head) {
238 /* New entry for the rhash_table */
239 err = rhashtable_lookup_insert_fast(&ilan->xlat.rhash_table,
240 &ila->node, rht_params);
241 } else {
242 struct ila_map *tila = head, *prev = NULL;
243
244 do {
245 if (!ila_cmp_params(tila, xp)) {
246 err = -EEXIST;
247 goto out;
248 }
249
250 if (order > ila_order(tila))
251 break;
252
253 prev = tila;
254 tila = rcu_dereference_protected(tila->next,
255 lockdep_is_held(lock));
256 } while (tila);
257
258 if (prev) {
259 /* Insert in sub list of head */
260 RCU_INIT_POINTER(ila->next, tila);
261 rcu_assign_pointer(prev->next, ila);
262 } else {
263 /* Make this ila new head */
264 RCU_INIT_POINTER(ila->next, head);
265 err = rhashtable_replace_fast(&ilan->xlat.rhash_table,
266 &head->node,
267 &ila->node, rht_params);
268 if (err)
269 goto out;
270 }
271 }
272
273 out:
274 spin_unlock(lock);
275
276 if (err)
277 kfree(ila);
278
279 return err;
280 }
281
282 static int ila_del_mapping(struct net *net, struct ila_xlat_params *xp)
283 {
284 struct ila_net *ilan = net_generic(net, ila_net_id);
285 struct ila_map *ila, *head, *prev;
286 spinlock_t *lock = ila_get_lock(ilan, xp->ip.locator_match);
287 int err = -ENOENT;
288
289 spin_lock(lock);
290
291 head = rhashtable_lookup_fast(&ilan->xlat.rhash_table,
292 &xp->ip.locator_match, rht_params);
293 ila = head;
294
295 prev = NULL;
296
297 while (ila) {
298 if (ila_cmp_params(ila, xp)) {
299 prev = ila;
300 ila = rcu_dereference_protected(ila->next,
301 lockdep_is_held(lock));
302 continue;
303 }
304
305 err = 0;
306
307 if (prev) {
308 /* Not head, just delete from list */
309 rcu_assign_pointer(prev->next, ila->next);
310 } else {
311 /* It is the head. If there is something in the
312 * sublist we need to make a new head.
313 */
314 head = rcu_dereference_protected(ila->next,
315 lockdep_is_held(lock));
316 if (head) {
317 /* Put first entry in the sublist into the
318 * table
319 */
320 err = rhashtable_replace_fast(
321 &ilan->xlat.rhash_table, &ila->node,
322 &head->node, rht_params);
323 if (err)
324 goto out;
325 } else {
326 /* Entry no longer used */
327 err = rhashtable_remove_fast(
328 &ilan->xlat.rhash_table,
329 &ila->node, rht_params);
330 }
331 }
332
333 ila_release(ila);
334
335 break;
336 }
337
338 out:
339 spin_unlock(lock);
340
341 return err;
342 }
343
344 int ila_xlat_nl_cmd_add_mapping(struct sk_buff *skb, struct genl_info *info)
345 {
346 struct net *net = genl_info_net(info);
347 struct ila_xlat_params p;
348 int err;
349
350 err = parse_nl_config(info, &p);
351 if (err)
352 return err;
353
354 return ila_add_mapping(net, &p);
355 }
356
357 int ila_xlat_nl_cmd_del_mapping(struct sk_buff *skb, struct genl_info *info)
358 {
359 struct net *net = genl_info_net(info);
360 struct ila_xlat_params xp;
361 int err;
362
363 err = parse_nl_config(info, &xp);
364 if (err)
365 return err;
366
367 ila_del_mapping(net, &xp);
368
369 return 0;
370 }
371
372 static inline spinlock_t *lock_from_ila_map(struct ila_net *ilan,
373 struct ila_map *ila)
374 {
375 return ila_get_lock(ilan, ila->xp.ip.locator_match);
376 }
377
378 int ila_xlat_nl_cmd_flush(struct sk_buff *skb, struct genl_info *info)
379 {
380 struct net *net = genl_info_net(info);
381 struct ila_net *ilan = net_generic(net, ila_net_id);
382 struct rhashtable_iter iter;
383 struct ila_map *ila;
384 spinlock_t *lock;
385 int ret = 0;
386
387 rhashtable_walk_enter(&ilan->xlat.rhash_table, &iter);
388 rhashtable_walk_start(&iter);
389
390 for (;;) {
391 ila = rhashtable_walk_next(&iter);
392
393 if (IS_ERR(ila)) {
394 if (PTR_ERR(ila) == -EAGAIN)
395 continue;
396 ret = PTR_ERR(ila);
397 goto done;
398 } else if (!ila) {
399 break;
400 }
401
402 lock = lock_from_ila_map(ilan, ila);
403
404 spin_lock(lock);
405
406 ret = rhashtable_remove_fast(&ilan->xlat.rhash_table,
407 &ila->node, rht_params);
408 if (!ret)
409 ila_free_node(ila);
410
411 spin_unlock(lock);
412
413 if (ret)
414 break;
415 }
416
417 done:
418 rhashtable_walk_stop(&iter);
419 rhashtable_walk_exit(&iter);
420 return ret;
421 }
422
423 static int ila_fill_info(struct ila_map *ila, struct sk_buff *msg)
424 {
425 if (nla_put_u64_64bit(msg, ILA_ATTR_LOCATOR,
426 (__force u64)ila->xp.ip.locator.v64,
427 ILA_ATTR_PAD) ||
428 nla_put_u64_64bit(msg, ILA_ATTR_LOCATOR_MATCH,
429 (__force u64)ila->xp.ip.locator_match.v64,
430 ILA_ATTR_PAD) ||
431 nla_put_s32(msg, ILA_ATTR_IFINDEX, ila->xp.ifindex) ||
432 nla_put_u8(msg, ILA_ATTR_CSUM_MODE, ila->xp.ip.csum_mode) ||
433 nla_put_u8(msg, ILA_ATTR_IDENT_TYPE, ila->xp.ip.ident_type))
434 return -1;
435
436 return 0;
437 }
438
439 static int ila_dump_info(struct ila_map *ila,
440 u32 portid, u32 seq, u32 flags,
441 struct sk_buff *skb, u8 cmd)
442 {
443 void *hdr;
444
445 hdr = genlmsg_put(skb, portid, seq, &ila_nl_family, flags, cmd);
446 if (!hdr)
447 return -ENOMEM;
448
449 if (ila_fill_info(ila, skb) < 0)
450 goto nla_put_failure;
451
452 genlmsg_end(skb, hdr);
453 return 0;
454
455 nla_put_failure:
456 genlmsg_cancel(skb, hdr);
457 return -EMSGSIZE;
458 }
459
460 int ila_xlat_nl_cmd_get_mapping(struct sk_buff *skb, struct genl_info *info)
461 {
462 struct net *net = genl_info_net(info);
463 struct ila_net *ilan = net_generic(net, ila_net_id);
464 struct sk_buff *msg;
465 struct ila_xlat_params xp;
466 struct ila_map *ila;
467 int ret;
468
469 ret = parse_nl_config(info, &xp);
470 if (ret)
471 return ret;
472
473 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
474 if (!msg)
475 return -ENOMEM;
476
477 rcu_read_lock();
478
479 ret = -ESRCH;
480 ila = ila_lookup_by_params(&xp, ilan);
481 if (ila) {
482 ret = ila_dump_info(ila,
483 info->snd_portid,
484 info->snd_seq, 0, msg,
485 info->genlhdr->cmd);
486 }
487
488 rcu_read_unlock();
489
490 if (ret < 0)
491 goto out_free;
492
493 return genlmsg_reply(msg, info);
494
495 out_free:
496 nlmsg_free(msg);
497 return ret;
498 }
499
500 struct ila_dump_iter {
501 struct rhashtable_iter rhiter;
502 int skip;
503 };
504
505 int ila_xlat_nl_dump_start(struct netlink_callback *cb)
506 {
507 struct net *net = sock_net(cb->skb->sk);
508 struct ila_net *ilan = net_generic(net, ila_net_id);
509 struct ila_dump_iter *iter;
510
511 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
512 if (!iter)
513 return -ENOMEM;
514
515 rhashtable_walk_enter(&ilan->xlat.rhash_table, &iter->rhiter);
516
517 iter->skip = 0;
518 cb->args[0] = (long)iter;
519
520 return 0;
521 }
522
523 int ila_xlat_nl_dump_done(struct netlink_callback *cb)
524 {
525 struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args[0];
526
527 rhashtable_walk_exit(&iter->rhiter);
528
529 kfree(iter);
530
531 return 0;
532 }
533
534 int ila_xlat_nl_dump(struct sk_buff *skb, struct netlink_callback *cb)
535 {
536 struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args[0];
537 struct rhashtable_iter *rhiter = &iter->rhiter;
538 int skip = iter->skip;
539 struct ila_map *ila;
540 int ret;
541
542 rhashtable_walk_start(rhiter);
543
544 /* Get first entry */
545 ila = rhashtable_walk_peek(rhiter);
546
547 if (ila && !IS_ERR(ila) && skip) {
548 /* Skip over visited entries */
549
550 while (ila && skip) {
551 /* Skip over any ila entries in this list that we
552 * have already dumped.
553 */
554 ila = rcu_access_pointer(ila->next);
555 skip--;
556 }
557 }
558
559 skip = 0;
560
561 for (;;) {
562 if (IS_ERR(ila)) {
563 ret = PTR_ERR(ila);
564 if (ret == -EAGAIN) {
565 /* Table has changed and iter has reset. Return
566 * -EAGAIN to the application even if we have
567 * written data to the skb. The application
568 * needs to deal with this.
569 */
570
571 goto out_ret;
572 } else {
573 break;
574 }
575 } else if (!ila) {
576 ret = 0;
577 break;
578 }
579
580 while (ila) {
581 ret = ila_dump_info(ila, NETLINK_CB(cb->skb).portid,
582 cb->nlh->nlmsg_seq, NLM_F_MULTI,
583 skb, ILA_CMD_GET);
584 if (ret)
585 goto out;
586
587 skip++;
588 ila = rcu_access_pointer(ila->next);
589 }
590
591 skip = 0;
592 ila = rhashtable_walk_next(rhiter);
593 }
594
595 out:
596 iter->skip = skip;
597 ret = (skb->len ? : ret);
598
599 out_ret:
600 rhashtable_walk_stop(rhiter);
601 return ret;
602 }
603
604 int ila_xlat_init_net(struct net *net)
605 {
606 struct ila_net *ilan = net_generic(net, ila_net_id);
607 int err;
608
609 err = alloc_ila_locks(ilan);
610 if (err)
611 return err;
612
613 err = rhashtable_init(&ilan->xlat.rhash_table, &rht_params);
614 if (err) {
615 free_bucket_spinlocks(ilan->xlat.locks);
616 return err;
617 }
618
619 return 0;
620 }
621
622 void ila_xlat_pre_exit_net(struct net *net)
623 {
624 struct ila_net *ilan = net_generic(net, ila_net_id);
625
626 if (ilan->xlat.hooks_registered)
627 nf_unregister_net_hooks(net, ila_nf_hook_ops,
628 ARRAY_SIZE(ila_nf_hook_ops));
629 }
630
631 void ila_xlat_exit_net(struct net *net)
632 {
633 struct ila_net *ilan = net_generic(net, ila_net_id);
634
635 rhashtable_free_and_destroy(&ilan->xlat.rhash_table, ila_free_cb, NULL);
636
637 free_bucket_spinlocks(ilan->xlat.locks);
638 }
639
640 static int ila_xlat_addr(struct sk_buff *skb, bool sir2ila)
641 {
642 struct ila_map *ila;
643 struct ipv6hdr *ip6h = ipv6_hdr(skb);
644 struct net *net = dev_net(skb->dev);
645 struct ila_net *ilan = net_generic(net, ila_net_id);
646 struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
647
648 /* Assumes skb contains a valid IPv6 header that is pulled */
649
650 /* No check here that ILA type in the mapping matches what is in the
651 * address. We assume that whatever sender gaves us can be translated.
652 * The checksum mode however is relevant.
653 */
654
655 rcu_read_lock();
656
657 ila = ila_lookup_wildcards(iaddr, skb->dev->ifindex, ilan);
658 if (ila)
659 ila_update_ipv6_locator(skb, &ila->xp.ip, sir2ila);
660
661 rcu_read_unlock();
662
663 return 0;
664 }
665
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.