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1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Management Component Transport Protocol (MCTP) - routing
4  * implementation.
5  *
6  * This is currently based on a simple routing table, with no dst cache. The
7  * number of routes should stay fairly small, so the lookup cost is small.
8  *
9  * Copyright (c) 2021 Code Construct
10  * Copyright (c) 2021 Google
11  */
12 
13 #include <linux/idr.h>
14 #include <linux/kconfig.h>
15 #include <linux/mctp.h>
16 #include <linux/netdevice.h>
17 #include <linux/rtnetlink.h>
18 #include <linux/skbuff.h>
19 
20 #include <uapi/linux/if_arp.h>
21 
22 #include <net/mctp.h>
23 #include <net/mctpdevice.h>
24 #include <net/netlink.h>
25 #include <net/sock.h>
26 
27 #include <trace/events/mctp.h>
28 
29 static const unsigned int mctp_message_maxlen = 64 * 1024;
30 static const unsigned long mctp_key_lifetime = 6 * CONFIG_HZ;
31 
32 static void mctp_flow_prepare_output(struct sk_buff *skb, struct mctp_dev *dev);
33 
34 /* route output callbacks */
mctp_route_discard(struct mctp_route * route,struct sk_buff * skb)35 static int mctp_route_discard(struct mctp_route *route, struct sk_buff *skb)
36 {
37 	kfree_skb(skb);
38 	return 0;
39 }
40 
mctp_lookup_bind(struct net * net,struct sk_buff * skb)41 static struct mctp_sock *mctp_lookup_bind(struct net *net, struct sk_buff *skb)
42 {
43 	struct mctp_skb_cb *cb = mctp_cb(skb);
44 	struct mctp_hdr *mh;
45 	struct sock *sk;
46 	u8 type;
47 
48 	WARN_ON(!rcu_read_lock_held());
49 
50 	/* TODO: look up in skb->cb? */
51 	mh = mctp_hdr(skb);
52 
53 	if (!skb_headlen(skb))
54 		return NULL;
55 
56 	type = (*(u8 *)skb->data) & 0x7f;
57 
58 	sk_for_each_rcu(sk, &net->mctp.binds) {
59 		struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);
60 
61 		if (msk->bind_net != MCTP_NET_ANY && msk->bind_net != cb->net)
62 			continue;
63 
64 		if (msk->bind_type != type)
65 			continue;
66 
67 		if (!mctp_address_matches(msk->bind_addr, mh->dest))
68 			continue;
69 
70 		return msk;
71 	}
72 
73 	return NULL;
74 }
75 
mctp_key_match(struct mctp_sk_key * key,mctp_eid_t local,mctp_eid_t peer,u8 tag)76 static bool mctp_key_match(struct mctp_sk_key *key, mctp_eid_t local,
77 			   mctp_eid_t peer, u8 tag)
78 {
79 	if (!mctp_address_matches(key->local_addr, local))
80 		return false;
81 
82 	if (key->peer_addr != peer)
83 		return false;
84 
85 	if (key->tag != tag)
86 		return false;
87 
88 	return true;
89 }
90 
91 /* returns a key (with key->lock held, and refcounted), or NULL if no such
92  * key exists.
93  */
mctp_lookup_key(struct net * net,struct sk_buff * skb,mctp_eid_t peer,unsigned long * irqflags)94 static struct mctp_sk_key *mctp_lookup_key(struct net *net, struct sk_buff *skb,
95 					   mctp_eid_t peer,
96 					   unsigned long *irqflags)
97 	__acquires(&key->lock)
98 {
99 	struct mctp_sk_key *key, *ret;
100 	unsigned long flags;
101 	struct mctp_hdr *mh;
102 	u8 tag;
103 
104 	mh = mctp_hdr(skb);
105 	tag = mh->flags_seq_tag & (MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO);
106 
107 	ret = NULL;
108 	spin_lock_irqsave(&net->mctp.keys_lock, flags);
109 
110 	hlist_for_each_entry(key, &net->mctp.keys, hlist) {
111 		if (!mctp_key_match(key, mh->dest, peer, tag))
112 			continue;
113 
114 		spin_lock(&key->lock);
115 		if (key->valid) {
116 			refcount_inc(&key->refs);
117 			ret = key;
118 			break;
119 		}
120 		spin_unlock(&key->lock);
121 	}
122 
123 	if (ret) {
124 		spin_unlock(&net->mctp.keys_lock);
125 		*irqflags = flags;
126 	} else {
127 		spin_unlock_irqrestore(&net->mctp.keys_lock, flags);
128 	}
129 
130 	return ret;
131 }
132 
mctp_key_alloc(struct mctp_sock * msk,mctp_eid_t local,mctp_eid_t peer,u8 tag,gfp_t gfp)133 static struct mctp_sk_key *mctp_key_alloc(struct mctp_sock *msk,
134 					  mctp_eid_t local, mctp_eid_t peer,
135 					  u8 tag, gfp_t gfp)
136 {
137 	struct mctp_sk_key *key;
138 
139 	key = kzalloc(sizeof(*key), gfp);
140 	if (!key)
141 		return NULL;
142 
143 	key->peer_addr = peer;
144 	key->local_addr = local;
145 	key->tag = tag;
146 	key->sk = &msk->sk;
147 	key->valid = true;
148 	spin_lock_init(&key->lock);
149 	refcount_set(&key->refs, 1);
150 	sock_hold(key->sk);
151 
152 	return key;
153 }
154 
mctp_key_unref(struct mctp_sk_key * key)155 void mctp_key_unref(struct mctp_sk_key *key)
156 {
157 	unsigned long flags;
158 
159 	if (!refcount_dec_and_test(&key->refs))
160 		return;
161 
162 	/* even though no refs exist here, the lock allows us to stay
163 	 * consistent with the locking requirement of mctp_dev_release_key
164 	 */
165 	spin_lock_irqsave(&key->lock, flags);
166 	mctp_dev_release_key(key->dev, key);
167 	spin_unlock_irqrestore(&key->lock, flags);
168 
169 	sock_put(key->sk);
170 	kfree(key);
171 }
172 
mctp_key_add(struct mctp_sk_key * key,struct mctp_sock * msk)173 static int mctp_key_add(struct mctp_sk_key *key, struct mctp_sock *msk)
174 {
175 	struct net *net = sock_net(&msk->sk);
176 	struct mctp_sk_key *tmp;
177 	unsigned long flags;
178 	int rc = 0;
179 
180 	spin_lock_irqsave(&net->mctp.keys_lock, flags);
181 
182 	if (sock_flag(&msk->sk, SOCK_DEAD)) {
183 		rc = -EINVAL;
184 		goto out_unlock;
185 	}
186 
187 	hlist_for_each_entry(tmp, &net->mctp.keys, hlist) {
188 		if (mctp_key_match(tmp, key->local_addr, key->peer_addr,
189 				   key->tag)) {
190 			spin_lock(&tmp->lock);
191 			if (tmp->valid)
192 				rc = -EEXIST;
193 			spin_unlock(&tmp->lock);
194 			if (rc)
195 				break;
196 		}
197 	}
198 
199 	if (!rc) {
200 		refcount_inc(&key->refs);
201 		key->expiry = jiffies + mctp_key_lifetime;
202 		timer_reduce(&msk->key_expiry, key->expiry);
203 
204 		hlist_add_head(&key->hlist, &net->mctp.keys);
205 		hlist_add_head(&key->sklist, &msk->keys);
206 	}
207 
208 out_unlock:
209 	spin_unlock_irqrestore(&net->mctp.keys_lock, flags);
210 
211 	return rc;
212 }
213 
214 /* Helper for mctp_route_input().
215  * We're done with the key; unlock and unref the key.
216  * For the usual case of automatic expiry we remove the key from lists.
217  * In the case that manual allocation is set on a key we release the lock
218  * and local ref, reset reassembly, but don't remove from lists.
219  */
__mctp_key_done_in(struct mctp_sk_key * key,struct net * net,unsigned long flags,unsigned long reason)220 static void __mctp_key_done_in(struct mctp_sk_key *key, struct net *net,
221 			       unsigned long flags, unsigned long reason)
222 __releases(&key->lock)
223 {
224 	struct sk_buff *skb;
225 
226 	trace_mctp_key_release(key, reason);
227 	skb = key->reasm_head;
228 	key->reasm_head = NULL;
229 
230 	if (!key->manual_alloc) {
231 		key->reasm_dead = true;
232 		key->valid = false;
233 		mctp_dev_release_key(key->dev, key);
234 	}
235 	spin_unlock_irqrestore(&key->lock, flags);
236 
237 	if (!key->manual_alloc) {
238 		spin_lock_irqsave(&net->mctp.keys_lock, flags);
239 		if (!hlist_unhashed(&key->hlist)) {
240 			hlist_del_init(&key->hlist);
241 			hlist_del_init(&key->sklist);
242 			mctp_key_unref(key);
243 		}
244 		spin_unlock_irqrestore(&net->mctp.keys_lock, flags);
245 	}
246 
247 	/* and one for the local reference */
248 	mctp_key_unref(key);
249 
250 	kfree_skb(skb);
251 }
252 
253 #ifdef CONFIG_MCTP_FLOWS
mctp_skb_set_flow(struct sk_buff * skb,struct mctp_sk_key * key)254 static void mctp_skb_set_flow(struct sk_buff *skb, struct mctp_sk_key *key)
255 {
256 	struct mctp_flow *flow;
257 
258 	flow = skb_ext_add(skb, SKB_EXT_MCTP);
259 	if (!flow)
260 		return;
261 
262 	refcount_inc(&key->refs);
263 	flow->key = key;
264 }
265 
mctp_flow_prepare_output(struct sk_buff * skb,struct mctp_dev * dev)266 static void mctp_flow_prepare_output(struct sk_buff *skb, struct mctp_dev *dev)
267 {
268 	struct mctp_sk_key *key;
269 	struct mctp_flow *flow;
270 
271 	flow = skb_ext_find(skb, SKB_EXT_MCTP);
272 	if (!flow)
273 		return;
274 
275 	key = flow->key;
276 
277 	if (key->dev) {
278 		WARN_ON(key->dev != dev);
279 		return;
280 	}
281 
282 	mctp_dev_set_key(dev, key);
283 }
284 #else
mctp_skb_set_flow(struct sk_buff * skb,struct mctp_sk_key * key)285 static void mctp_skb_set_flow(struct sk_buff *skb, struct mctp_sk_key *key) {}
mctp_flow_prepare_output(struct sk_buff * skb,struct mctp_dev * dev)286 static void mctp_flow_prepare_output(struct sk_buff *skb, struct mctp_dev *dev) {}
287 #endif
288 
mctp_frag_queue(struct mctp_sk_key * key,struct sk_buff * skb)289 static int mctp_frag_queue(struct mctp_sk_key *key, struct sk_buff *skb)
290 {
291 	struct mctp_hdr *hdr = mctp_hdr(skb);
292 	u8 exp_seq, this_seq;
293 
294 	this_seq = (hdr->flags_seq_tag >> MCTP_HDR_SEQ_SHIFT)
295 		& MCTP_HDR_SEQ_MASK;
296 
297 	if (!key->reasm_head) {
298 		key->reasm_head = skb;
299 		key->reasm_tailp = &(skb_shinfo(skb)->frag_list);
300 		key->last_seq = this_seq;
301 		return 0;
302 	}
303 
304 	exp_seq = (key->last_seq + 1) & MCTP_HDR_SEQ_MASK;
305 
306 	if (this_seq != exp_seq)
307 		return -EINVAL;
308 
309 	if (key->reasm_head->len + skb->len > mctp_message_maxlen)
310 		return -EINVAL;
311 
312 	skb->next = NULL;
313 	skb->sk = NULL;
314 	*key->reasm_tailp = skb;
315 	key->reasm_tailp = &skb->next;
316 
317 	key->last_seq = this_seq;
318 
319 	key->reasm_head->data_len += skb->len;
320 	key->reasm_head->len += skb->len;
321 	key->reasm_head->truesize += skb->truesize;
322 
323 	return 0;
324 }
325 
mctp_route_input(struct mctp_route * route,struct sk_buff * skb)326 static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb)
327 {
328 	struct mctp_sk_key *key, *any_key = NULL;
329 	struct net *net = dev_net(skb->dev);
330 	struct mctp_sock *msk;
331 	struct mctp_hdr *mh;
332 	unsigned long f;
333 	u8 tag, flags;
334 	int rc;
335 
336 	msk = NULL;
337 	rc = -EINVAL;
338 
339 	/* We may be receiving a locally-routed packet; drop source sk
340 	 * accounting.
341 	 *
342 	 * From here, we will either queue the skb - either to a frag_queue, or
343 	 * to a receiving socket. When that succeeds, we clear the skb pointer;
344 	 * a non-NULL skb on exit will be otherwise unowned, and hence
345 	 * kfree_skb()-ed.
346 	 */
347 	skb_orphan(skb);
348 
349 	/* ensure we have enough data for a header and a type */
350 	if (skb->len < sizeof(struct mctp_hdr) + 1)
351 		goto out;
352 
353 	/* grab header, advance data ptr */
354 	mh = mctp_hdr(skb);
355 	skb_pull(skb, sizeof(struct mctp_hdr));
356 
357 	if (mh->ver != 1)
358 		goto out;
359 
360 	flags = mh->flags_seq_tag & (MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM);
361 	tag = mh->flags_seq_tag & (MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO);
362 
363 	rcu_read_lock();
364 
365 	/* lookup socket / reasm context, exactly matching (src,dest,tag).
366 	 * we hold a ref on the key, and key->lock held.
367 	 */
368 	key = mctp_lookup_key(net, skb, mh->src, &f);
369 
370 	if (flags & MCTP_HDR_FLAG_SOM) {
371 		if (key) {
372 			msk = container_of(key->sk, struct mctp_sock, sk);
373 		} else {
374 			/* first response to a broadcast? do a more general
375 			 * key lookup to find the socket, but don't use this
376 			 * key for reassembly - we'll create a more specific
377 			 * one for future packets if required (ie, !EOM).
378 			 */
379 			any_key = mctp_lookup_key(net, skb, MCTP_ADDR_ANY, &f);
380 			if (any_key) {
381 				msk = container_of(any_key->sk,
382 						   struct mctp_sock, sk);
383 				spin_unlock_irqrestore(&any_key->lock, f);
384 			}
385 		}
386 
387 		if (!key && !msk && (tag & MCTP_HDR_FLAG_TO))
388 			msk = mctp_lookup_bind(net, skb);
389 
390 		if (!msk) {
391 			rc = -ENOENT;
392 			goto out_unlock;
393 		}
394 
395 		/* single-packet message? deliver to socket, clean up any
396 		 * pending key.
397 		 */
398 		if (flags & MCTP_HDR_FLAG_EOM) {
399 			rc = sock_queue_rcv_skb(&msk->sk, skb);
400 			if (!rc)
401 				skb = NULL;
402 			if (key) {
403 				/* we've hit a pending reassembly; not much we
404 				 * can do but drop it
405 				 */
406 				__mctp_key_done_in(key, net, f,
407 						   MCTP_TRACE_KEY_REPLIED);
408 				key = NULL;
409 			}
410 			goto out_unlock;
411 		}
412 
413 		/* broadcast response or a bind() - create a key for further
414 		 * packets for this message
415 		 */
416 		if (!key) {
417 			key = mctp_key_alloc(msk, mh->dest, mh->src,
418 					     tag, GFP_ATOMIC);
419 			if (!key) {
420 				rc = -ENOMEM;
421 				goto out_unlock;
422 			}
423 
424 			/* we can queue without the key lock here, as the
425 			 * key isn't observable yet
426 			 */
427 			mctp_frag_queue(key, skb);
428 
429 			/* if the key_add fails, we've raced with another
430 			 * SOM packet with the same src, dest and tag. There's
431 			 * no way to distinguish future packets, so all we
432 			 * can do is drop; we'll free the skb on exit from
433 			 * this function.
434 			 */
435 			rc = mctp_key_add(key, msk);
436 			if (!rc) {
437 				trace_mctp_key_acquire(key);
438 				skb = NULL;
439 			}
440 
441 			/* we don't need to release key->lock on exit, so
442 			 * clean up here and suppress the unlock via
443 			 * setting to NULL
444 			 */
445 			mctp_key_unref(key);
446 			key = NULL;
447 
448 		} else {
449 			if (key->reasm_head || key->reasm_dead) {
450 				/* duplicate start? drop everything */
451 				__mctp_key_done_in(key, net, f,
452 						   MCTP_TRACE_KEY_INVALIDATED);
453 				rc = -EEXIST;
454 				key = NULL;
455 			} else {
456 				rc = mctp_frag_queue(key, skb);
457 				if (!rc)
458 					skb = NULL;
459 			}
460 		}
461 
462 	} else if (key) {
463 		/* this packet continues a previous message; reassemble
464 		 * using the message-specific key
465 		 */
466 
467 		/* we need to be continuing an existing reassembly... */
468 		if (!key->reasm_head)
469 			rc = -EINVAL;
470 		else
471 			rc = mctp_frag_queue(key, skb);
472 
473 		if (rc)
474 			goto out_unlock;
475 
476 		/* we've queued; the queue owns the skb now */
477 		skb = NULL;
478 
479 		/* end of message? deliver to socket, and we're done with
480 		 * the reassembly/response key
481 		 */
482 		if (flags & MCTP_HDR_FLAG_EOM) {
483 			rc = sock_queue_rcv_skb(key->sk, key->reasm_head);
484 			if (!rc)
485 				key->reasm_head = NULL;
486 			__mctp_key_done_in(key, net, f, MCTP_TRACE_KEY_REPLIED);
487 			key = NULL;
488 		}
489 
490 	} else {
491 		/* not a start, no matching key */
492 		rc = -ENOENT;
493 	}
494 
495 out_unlock:
496 	rcu_read_unlock();
497 	if (key) {
498 		spin_unlock_irqrestore(&key->lock, f);
499 		mctp_key_unref(key);
500 	}
501 	if (any_key)
502 		mctp_key_unref(any_key);
503 out:
504 	kfree_skb(skb);
505 	return rc;
506 }
507 
mctp_route_mtu(struct mctp_route * rt)508 static unsigned int mctp_route_mtu(struct mctp_route *rt)
509 {
510 	return rt->mtu ?: READ_ONCE(rt->dev->dev->mtu);
511 }
512 
mctp_route_output(struct mctp_route * route,struct sk_buff * skb)513 static int mctp_route_output(struct mctp_route *route, struct sk_buff *skb)
514 {
515 	struct mctp_skb_cb *cb = mctp_cb(skb);
516 	struct mctp_hdr *hdr = mctp_hdr(skb);
517 	char daddr_buf[MAX_ADDR_LEN];
518 	char *daddr = NULL;
519 	unsigned int mtu;
520 	int rc;
521 
522 	skb->protocol = htons(ETH_P_MCTP);
523 
524 	mtu = READ_ONCE(skb->dev->mtu);
525 	if (skb->len > mtu) {
526 		kfree_skb(skb);
527 		return -EMSGSIZE;
528 	}
529 
530 	if (cb->ifindex) {
531 		/* direct route; use the hwaddr we stashed in sendmsg */
532 		if (cb->halen != skb->dev->addr_len) {
533 			/* sanity check, sendmsg should have already caught this */
534 			kfree_skb(skb);
535 			return -EMSGSIZE;
536 		}
537 		daddr = cb->haddr;
538 	} else {
539 		/* If lookup fails let the device handle daddr==NULL */
540 		if (mctp_neigh_lookup(route->dev, hdr->dest, daddr_buf) == 0)
541 			daddr = daddr_buf;
542 	}
543 
544 	rc = dev_hard_header(skb, skb->dev, ntohs(skb->protocol),
545 			     daddr, skb->dev->dev_addr, skb->len);
546 	if (rc < 0) {
547 		kfree_skb(skb);
548 		return -EHOSTUNREACH;
549 	}
550 
551 	mctp_flow_prepare_output(skb, route->dev);
552 
553 	rc = dev_queue_xmit(skb);
554 	if (rc)
555 		rc = net_xmit_errno(rc);
556 
557 	return rc;
558 }
559 
560 /* route alloc/release */
mctp_route_release(struct mctp_route * rt)561 static void mctp_route_release(struct mctp_route *rt)
562 {
563 	if (refcount_dec_and_test(&rt->refs)) {
564 		mctp_dev_put(rt->dev);
565 		kfree_rcu(rt, rcu);
566 	}
567 }
568 
569 /* returns a route with the refcount at 1 */
mctp_route_alloc(void)570 static struct mctp_route *mctp_route_alloc(void)
571 {
572 	struct mctp_route *rt;
573 
574 	rt = kzalloc(sizeof(*rt), GFP_KERNEL);
575 	if (!rt)
576 		return NULL;
577 
578 	INIT_LIST_HEAD(&rt->list);
579 	refcount_set(&rt->refs, 1);
580 	rt->output = mctp_route_discard;
581 
582 	return rt;
583 }
584 
mctp_default_net(struct net * net)585 unsigned int mctp_default_net(struct net *net)
586 {
587 	return READ_ONCE(net->mctp.default_net);
588 }
589 
mctp_default_net_set(struct net * net,unsigned int index)590 int mctp_default_net_set(struct net *net, unsigned int index)
591 {
592 	if (index == 0)
593 		return -EINVAL;
594 	WRITE_ONCE(net->mctp.default_net, index);
595 	return 0;
596 }
597 
598 /* tag management */
mctp_reserve_tag(struct net * net,struct mctp_sk_key * key,struct mctp_sock * msk)599 static void mctp_reserve_tag(struct net *net, struct mctp_sk_key *key,
600 			     struct mctp_sock *msk)
601 {
602 	struct netns_mctp *mns = &net->mctp;
603 
604 	lockdep_assert_held(&mns->keys_lock);
605 
606 	key->expiry = jiffies + mctp_key_lifetime;
607 	timer_reduce(&msk->key_expiry, key->expiry);
608 
609 	/* we hold the net->key_lock here, allowing updates to both
610 	 * then net and sk
611 	 */
612 	hlist_add_head_rcu(&key->hlist, &mns->keys);
613 	hlist_add_head_rcu(&key->sklist, &msk->keys);
614 	refcount_inc(&key->refs);
615 }
616 
617 /* Allocate a locally-owned tag value for (saddr, daddr), and reserve
618  * it for the socket msk
619  */
mctp_alloc_local_tag(struct mctp_sock * msk,mctp_eid_t daddr,mctp_eid_t saddr,bool manual,u8 * tagp)620 struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk,
621 					 mctp_eid_t daddr, mctp_eid_t saddr,
622 					 bool manual, u8 *tagp)
623 {
624 	struct net *net = sock_net(&msk->sk);
625 	struct netns_mctp *mns = &net->mctp;
626 	struct mctp_sk_key *key, *tmp;
627 	unsigned long flags;
628 	u8 tagbits;
629 
630 	/* for NULL destination EIDs, we may get a response from any peer */
631 	if (daddr == MCTP_ADDR_NULL)
632 		daddr = MCTP_ADDR_ANY;
633 
634 	/* be optimistic, alloc now */
635 	key = mctp_key_alloc(msk, saddr, daddr, 0, GFP_KERNEL);
636 	if (!key)
637 		return ERR_PTR(-ENOMEM);
638 
639 	/* 8 possible tag values */
640 	tagbits = 0xff;
641 
642 	spin_lock_irqsave(&mns->keys_lock, flags);
643 
644 	/* Walk through the existing keys, looking for potential conflicting
645 	 * tags. If we find a conflict, clear that bit from tagbits
646 	 */
647 	hlist_for_each_entry(tmp, &mns->keys, hlist) {
648 		/* We can check the lookup fields (*_addr, tag) without the
649 		 * lock held, they don't change over the lifetime of the key.
650 		 */
651 
652 		/* if we don't own the tag, it can't conflict */
653 		if (tmp->tag & MCTP_HDR_FLAG_TO)
654 			continue;
655 
656 		if (!(mctp_address_matches(tmp->peer_addr, daddr) &&
657 		      mctp_address_matches(tmp->local_addr, saddr)))
658 			continue;
659 
660 		spin_lock(&tmp->lock);
661 		/* key must still be valid. If we find a match, clear the
662 		 * potential tag value
663 		 */
664 		if (tmp->valid)
665 			tagbits &= ~(1 << tmp->tag);
666 		spin_unlock(&tmp->lock);
667 
668 		if (!tagbits)
669 			break;
670 	}
671 
672 	if (tagbits) {
673 		key->tag = __ffs(tagbits);
674 		mctp_reserve_tag(net, key, msk);
675 		trace_mctp_key_acquire(key);
676 
677 		key->manual_alloc = manual;
678 		*tagp = key->tag;
679 	}
680 
681 	spin_unlock_irqrestore(&mns->keys_lock, flags);
682 
683 	if (!tagbits) {
684 		mctp_key_unref(key);
685 		return ERR_PTR(-EBUSY);
686 	}
687 
688 	return key;
689 }
690 
mctp_lookup_prealloc_tag(struct mctp_sock * msk,mctp_eid_t daddr,u8 req_tag,u8 * tagp)691 static struct mctp_sk_key *mctp_lookup_prealloc_tag(struct mctp_sock *msk,
692 						    mctp_eid_t daddr,
693 						    u8 req_tag, u8 *tagp)
694 {
695 	struct net *net = sock_net(&msk->sk);
696 	struct netns_mctp *mns = &net->mctp;
697 	struct mctp_sk_key *key, *tmp;
698 	unsigned long flags;
699 
700 	req_tag &= ~(MCTP_TAG_PREALLOC | MCTP_TAG_OWNER);
701 	key = NULL;
702 
703 	spin_lock_irqsave(&mns->keys_lock, flags);
704 
705 	hlist_for_each_entry(tmp, &mns->keys, hlist) {
706 		if (tmp->tag != req_tag)
707 			continue;
708 
709 		if (!mctp_address_matches(tmp->peer_addr, daddr))
710 			continue;
711 
712 		if (!tmp->manual_alloc)
713 			continue;
714 
715 		spin_lock(&tmp->lock);
716 		if (tmp->valid) {
717 			key = tmp;
718 			refcount_inc(&key->refs);
719 			spin_unlock(&tmp->lock);
720 			break;
721 		}
722 		spin_unlock(&tmp->lock);
723 	}
724 	spin_unlock_irqrestore(&mns->keys_lock, flags);
725 
726 	if (!key)
727 		return ERR_PTR(-ENOENT);
728 
729 	if (tagp)
730 		*tagp = key->tag;
731 
732 	return key;
733 }
734 
735 /* routing lookups */
mctp_rt_match_eid(struct mctp_route * rt,unsigned int net,mctp_eid_t eid)736 static bool mctp_rt_match_eid(struct mctp_route *rt,
737 			      unsigned int net, mctp_eid_t eid)
738 {
739 	return READ_ONCE(rt->dev->net) == net &&
740 		rt->min <= eid && rt->max >= eid;
741 }
742 
743 /* compares match, used for duplicate prevention */
mctp_rt_compare_exact(struct mctp_route * rt1,struct mctp_route * rt2)744 static bool mctp_rt_compare_exact(struct mctp_route *rt1,
745 				  struct mctp_route *rt2)
746 {
747 	ASSERT_RTNL();
748 	return rt1->dev->net == rt2->dev->net &&
749 		rt1->min == rt2->min &&
750 		rt1->max == rt2->max;
751 }
752 
mctp_route_lookup(struct net * net,unsigned int dnet,mctp_eid_t daddr)753 struct mctp_route *mctp_route_lookup(struct net *net, unsigned int dnet,
754 				     mctp_eid_t daddr)
755 {
756 	struct mctp_route *tmp, *rt = NULL;
757 
758 	rcu_read_lock();
759 
760 	list_for_each_entry_rcu(tmp, &net->mctp.routes, list) {
761 		/* TODO: add metrics */
762 		if (mctp_rt_match_eid(tmp, dnet, daddr)) {
763 			if (refcount_inc_not_zero(&tmp->refs)) {
764 				rt = tmp;
765 				break;
766 			}
767 		}
768 	}
769 
770 	rcu_read_unlock();
771 
772 	return rt;
773 }
774 
mctp_route_lookup_null(struct net * net,struct net_device * dev)775 static struct mctp_route *mctp_route_lookup_null(struct net *net,
776 						 struct net_device *dev)
777 {
778 	struct mctp_route *tmp, *rt = NULL;
779 
780 	rcu_read_lock();
781 
782 	list_for_each_entry_rcu(tmp, &net->mctp.routes, list) {
783 		if (tmp->dev->dev == dev && tmp->type == RTN_LOCAL &&
784 		    refcount_inc_not_zero(&tmp->refs)) {
785 			rt = tmp;
786 			break;
787 		}
788 	}
789 
790 	rcu_read_unlock();
791 
792 	return rt;
793 }
794 
mctp_do_fragment_route(struct mctp_route * rt,struct sk_buff * skb,unsigned int mtu,u8 tag)795 static int mctp_do_fragment_route(struct mctp_route *rt, struct sk_buff *skb,
796 				  unsigned int mtu, u8 tag)
797 {
798 	const unsigned int hlen = sizeof(struct mctp_hdr);
799 	struct mctp_hdr *hdr, *hdr2;
800 	unsigned int pos, size, headroom;
801 	struct sk_buff *skb2;
802 	int rc;
803 	u8 seq;
804 
805 	hdr = mctp_hdr(skb);
806 	seq = 0;
807 	rc = 0;
808 
809 	if (mtu < hlen + 1) {
810 		kfree_skb(skb);
811 		return -EMSGSIZE;
812 	}
813 
814 	/* keep same headroom as the original skb */
815 	headroom = skb_headroom(skb);
816 
817 	/* we've got the header */
818 	skb_pull(skb, hlen);
819 
820 	for (pos = 0; pos < skb->len;) {
821 		/* size of message payload */
822 		size = min(mtu - hlen, skb->len - pos);
823 
824 		skb2 = alloc_skb(headroom + hlen + size, GFP_KERNEL);
825 		if (!skb2) {
826 			rc = -ENOMEM;
827 			break;
828 		}
829 
830 		/* generic skb copy */
831 		skb2->protocol = skb->protocol;
832 		skb2->priority = skb->priority;
833 		skb2->dev = skb->dev;
834 		memcpy(skb2->cb, skb->cb, sizeof(skb2->cb));
835 
836 		if (skb->sk)
837 			skb_set_owner_w(skb2, skb->sk);
838 
839 		/* establish packet */
840 		skb_reserve(skb2, headroom);
841 		skb_reset_network_header(skb2);
842 		skb_put(skb2, hlen + size);
843 		skb2->transport_header = skb2->network_header + hlen;
844 
845 		/* copy header fields, calculate SOM/EOM flags & seq */
846 		hdr2 = mctp_hdr(skb2);
847 		hdr2->ver = hdr->ver;
848 		hdr2->dest = hdr->dest;
849 		hdr2->src = hdr->src;
850 		hdr2->flags_seq_tag = tag &
851 			(MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO);
852 
853 		if (pos == 0)
854 			hdr2->flags_seq_tag |= MCTP_HDR_FLAG_SOM;
855 
856 		if (pos + size == skb->len)
857 			hdr2->flags_seq_tag |= MCTP_HDR_FLAG_EOM;
858 
859 		hdr2->flags_seq_tag |= seq << MCTP_HDR_SEQ_SHIFT;
860 
861 		/* copy message payload */
862 		skb_copy_bits(skb, pos, skb_transport_header(skb2), size);
863 
864 		/* we need to copy the extensions, for MCTP flow data */
865 		skb_ext_copy(skb2, skb);
866 
867 		/* do route */
868 		rc = rt->output(rt, skb2);
869 		if (rc)
870 			break;
871 
872 		seq = (seq + 1) & MCTP_HDR_SEQ_MASK;
873 		pos += size;
874 	}
875 
876 	consume_skb(skb);
877 	return rc;
878 }
879 
mctp_local_output(struct sock * sk,struct mctp_route * rt,struct sk_buff * skb,mctp_eid_t daddr,u8 req_tag)880 int mctp_local_output(struct sock *sk, struct mctp_route *rt,
881 		      struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag)
882 {
883 	struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);
884 	struct mctp_skb_cb *cb = mctp_cb(skb);
885 	struct mctp_route tmp_rt = {0};
886 	struct mctp_sk_key *key;
887 	struct mctp_hdr *hdr;
888 	unsigned long flags;
889 	unsigned int mtu;
890 	mctp_eid_t saddr;
891 	bool ext_rt;
892 	int rc;
893 	u8 tag;
894 
895 	rc = -ENODEV;
896 
897 	if (rt) {
898 		ext_rt = false;
899 		if (WARN_ON(!rt->dev))
900 			goto out_release;
901 
902 	} else if (cb->ifindex) {
903 		struct net_device *dev;
904 
905 		ext_rt = true;
906 		rt = &tmp_rt;
907 
908 		rcu_read_lock();
909 		dev = dev_get_by_index_rcu(sock_net(sk), cb->ifindex);
910 		if (!dev) {
911 			rcu_read_unlock();
912 			goto out_free;
913 		}
914 		rt->dev = __mctp_dev_get(dev);
915 		rcu_read_unlock();
916 
917 		if (!rt->dev)
918 			goto out_release;
919 
920 		/* establish temporary route - we set up enough to keep
921 		 * mctp_route_output happy
922 		 */
923 		rt->output = mctp_route_output;
924 		rt->mtu = 0;
925 
926 	} else {
927 		rc = -EINVAL;
928 		goto out_free;
929 	}
930 
931 	spin_lock_irqsave(&rt->dev->addrs_lock, flags);
932 	if (rt->dev->num_addrs == 0) {
933 		rc = -EHOSTUNREACH;
934 	} else {
935 		/* use the outbound interface's first address as our source */
936 		saddr = rt->dev->addrs[0];
937 		rc = 0;
938 	}
939 	spin_unlock_irqrestore(&rt->dev->addrs_lock, flags);
940 
941 	if (rc)
942 		goto out_release;
943 
944 	if (req_tag & MCTP_TAG_OWNER) {
945 		if (req_tag & MCTP_TAG_PREALLOC)
946 			key = mctp_lookup_prealloc_tag(msk, daddr,
947 						       req_tag, &tag);
948 		else
949 			key = mctp_alloc_local_tag(msk, daddr, saddr,
950 						   false, &tag);
951 
952 		if (IS_ERR(key)) {
953 			rc = PTR_ERR(key);
954 			goto out_release;
955 		}
956 		mctp_skb_set_flow(skb, key);
957 		/* done with the key in this scope */
958 		mctp_key_unref(key);
959 		tag |= MCTP_HDR_FLAG_TO;
960 	} else {
961 		key = NULL;
962 		tag = req_tag & MCTP_TAG_MASK;
963 	}
964 
965 	skb->protocol = htons(ETH_P_MCTP);
966 	skb->priority = 0;
967 	skb_reset_transport_header(skb);
968 	skb_push(skb, sizeof(struct mctp_hdr));
969 	skb_reset_network_header(skb);
970 	skb->dev = rt->dev->dev;
971 
972 	/* cb->net will have been set on initial ingress */
973 	cb->src = saddr;
974 
975 	/* set up common header fields */
976 	hdr = mctp_hdr(skb);
977 	hdr->ver = 1;
978 	hdr->dest = daddr;
979 	hdr->src = saddr;
980 
981 	mtu = mctp_route_mtu(rt);
982 
983 	if (skb->len + sizeof(struct mctp_hdr) <= mtu) {
984 		hdr->flags_seq_tag = MCTP_HDR_FLAG_SOM |
985 			MCTP_HDR_FLAG_EOM | tag;
986 		rc = rt->output(rt, skb);
987 	} else {
988 		rc = mctp_do_fragment_route(rt, skb, mtu, tag);
989 	}
990 
991 	/* route output functions consume the skb, even on error */
992 	skb = NULL;
993 
994 out_release:
995 	if (!ext_rt)
996 		mctp_route_release(rt);
997 
998 	mctp_dev_put(tmp_rt.dev);
999 
1000 out_free:
1001 	kfree_skb(skb);
1002 	return rc;
1003 }
1004 
1005 /* route management */
mctp_route_add(struct mctp_dev * mdev,mctp_eid_t daddr_start,unsigned int daddr_extent,unsigned int mtu,unsigned char type)1006 static int mctp_route_add(struct mctp_dev *mdev, mctp_eid_t daddr_start,
1007 			  unsigned int daddr_extent, unsigned int mtu,
1008 			  unsigned char type)
1009 {
1010 	int (*rtfn)(struct mctp_route *rt, struct sk_buff *skb);
1011 	struct net *net = dev_net(mdev->dev);
1012 	struct mctp_route *rt, *ert;
1013 
1014 	if (!mctp_address_unicast(daddr_start))
1015 		return -EINVAL;
1016 
1017 	if (daddr_extent > 0xff || daddr_start + daddr_extent >= 255)
1018 		return -EINVAL;
1019 
1020 	switch (type) {
1021 	case RTN_LOCAL:
1022 		rtfn = mctp_route_input;
1023 		break;
1024 	case RTN_UNICAST:
1025 		rtfn = mctp_route_output;
1026 		break;
1027 	default:
1028 		return -EINVAL;
1029 	}
1030 
1031 	rt = mctp_route_alloc();
1032 	if (!rt)
1033 		return -ENOMEM;
1034 
1035 	rt->min = daddr_start;
1036 	rt->max = daddr_start + daddr_extent;
1037 	rt->mtu = mtu;
1038 	rt->dev = mdev;
1039 	mctp_dev_hold(rt->dev);
1040 	rt->type = type;
1041 	rt->output = rtfn;
1042 
1043 	ASSERT_RTNL();
1044 	/* Prevent duplicate identical routes. */
1045 	list_for_each_entry(ert, &net->mctp.routes, list) {
1046 		if (mctp_rt_compare_exact(rt, ert)) {
1047 			mctp_route_release(rt);
1048 			return -EEXIST;
1049 		}
1050 	}
1051 
1052 	list_add_rcu(&rt->list, &net->mctp.routes);
1053 
1054 	return 0;
1055 }
1056 
mctp_route_remove(struct mctp_dev * mdev,mctp_eid_t daddr_start,unsigned int daddr_extent,unsigned char type)1057 static int mctp_route_remove(struct mctp_dev *mdev, mctp_eid_t daddr_start,
1058 			     unsigned int daddr_extent, unsigned char type)
1059 {
1060 	struct net *net = dev_net(mdev->dev);
1061 	struct mctp_route *rt, *tmp;
1062 	mctp_eid_t daddr_end;
1063 	bool dropped;
1064 
1065 	if (daddr_extent > 0xff || daddr_start + daddr_extent >= 255)
1066 		return -EINVAL;
1067 
1068 	daddr_end = daddr_start + daddr_extent;
1069 	dropped = false;
1070 
1071 	ASSERT_RTNL();
1072 
1073 	list_for_each_entry_safe(rt, tmp, &net->mctp.routes, list) {
1074 		if (rt->dev == mdev &&
1075 		    rt->min == daddr_start && rt->max == daddr_end &&
1076 		    rt->type == type) {
1077 			list_del_rcu(&rt->list);
1078 			/* TODO: immediate RTM_DELROUTE */
1079 			mctp_route_release(rt);
1080 			dropped = true;
1081 		}
1082 	}
1083 
1084 	return dropped ? 0 : -ENOENT;
1085 }
1086 
mctp_route_add_local(struct mctp_dev * mdev,mctp_eid_t addr)1087 int mctp_route_add_local(struct mctp_dev *mdev, mctp_eid_t addr)
1088 {
1089 	return mctp_route_add(mdev, addr, 0, 0, RTN_LOCAL);
1090 }
1091 
mctp_route_remove_local(struct mctp_dev * mdev,mctp_eid_t addr)1092 int mctp_route_remove_local(struct mctp_dev *mdev, mctp_eid_t addr)
1093 {
1094 	return mctp_route_remove(mdev, addr, 0, RTN_LOCAL);
1095 }
1096 
1097 /* removes all entries for a given device */
mctp_route_remove_dev(struct mctp_dev * mdev)1098 void mctp_route_remove_dev(struct mctp_dev *mdev)
1099 {
1100 	struct net *net = dev_net(mdev->dev);
1101 	struct mctp_route *rt, *tmp;
1102 
1103 	ASSERT_RTNL();
1104 	list_for_each_entry_safe(rt, tmp, &net->mctp.routes, list) {
1105 		if (rt->dev == mdev) {
1106 			list_del_rcu(&rt->list);
1107 			/* TODO: immediate RTM_DELROUTE */
1108 			mctp_route_release(rt);
1109 		}
1110 	}
1111 }
1112 
1113 /* Incoming packet-handling */
1114 
mctp_pkttype_receive(struct sk_buff * skb,struct net_device * dev,struct packet_type * pt,struct net_device * orig_dev)1115 static int mctp_pkttype_receive(struct sk_buff *skb, struct net_device *dev,
1116 				struct packet_type *pt,
1117 				struct net_device *orig_dev)
1118 {
1119 	struct net *net = dev_net(dev);
1120 	struct mctp_dev *mdev;
1121 	struct mctp_skb_cb *cb;
1122 	struct mctp_route *rt;
1123 	struct mctp_hdr *mh;
1124 
1125 	rcu_read_lock();
1126 	mdev = __mctp_dev_get(dev);
1127 	rcu_read_unlock();
1128 	if (!mdev) {
1129 		/* basic non-data sanity checks */
1130 		goto err_drop;
1131 	}
1132 
1133 	if (!pskb_may_pull(skb, sizeof(struct mctp_hdr)))
1134 		goto err_drop;
1135 
1136 	skb_reset_transport_header(skb);
1137 	skb_reset_network_header(skb);
1138 
1139 	/* We have enough for a header; decode and route */
1140 	mh = mctp_hdr(skb);
1141 	if (mh->ver < MCTP_VER_MIN || mh->ver > MCTP_VER_MAX)
1142 		goto err_drop;
1143 
1144 	/* source must be valid unicast or null; drop reserved ranges and
1145 	 * broadcast
1146 	 */
1147 	if (!(mctp_address_unicast(mh->src) || mctp_address_null(mh->src)))
1148 		goto err_drop;
1149 
1150 	/* dest address: as above, but allow broadcast */
1151 	if (!(mctp_address_unicast(mh->dest) || mctp_address_null(mh->dest) ||
1152 	      mctp_address_broadcast(mh->dest)))
1153 		goto err_drop;
1154 
1155 	/* MCTP drivers must populate halen/haddr */
1156 	if (dev->type == ARPHRD_MCTP) {
1157 		cb = mctp_cb(skb);
1158 	} else {
1159 		cb = __mctp_cb(skb);
1160 		cb->halen = 0;
1161 	}
1162 	cb->net = READ_ONCE(mdev->net);
1163 	cb->ifindex = dev->ifindex;
1164 
1165 	rt = mctp_route_lookup(net, cb->net, mh->dest);
1166 
1167 	/* NULL EID, but addressed to our physical address */
1168 	if (!rt && mh->dest == MCTP_ADDR_NULL && skb->pkt_type == PACKET_HOST)
1169 		rt = mctp_route_lookup_null(net, dev);
1170 
1171 	if (!rt)
1172 		goto err_drop;
1173 
1174 	rt->output(rt, skb);
1175 	mctp_route_release(rt);
1176 	mctp_dev_put(mdev);
1177 
1178 	return NET_RX_SUCCESS;
1179 
1180 err_drop:
1181 	kfree_skb(skb);
1182 	mctp_dev_put(mdev);
1183 	return NET_RX_DROP;
1184 }
1185 
1186 static struct packet_type mctp_packet_type = {
1187 	.type = cpu_to_be16(ETH_P_MCTP),
1188 	.func = mctp_pkttype_receive,
1189 };
1190 
1191 /* netlink interface */
1192 
1193 static const struct nla_policy rta_mctp_policy[RTA_MAX + 1] = {
1194 	[RTA_DST]		= { .type = NLA_U8 },
1195 	[RTA_METRICS]		= { .type = NLA_NESTED },
1196 	[RTA_OIF]		= { .type = NLA_U32 },
1197 };
1198 
1199 /* Common part for RTM_NEWROUTE and RTM_DELROUTE parsing.
1200  * tb must hold RTA_MAX+1 elements.
1201  */
mctp_route_nlparse(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack,struct nlattr ** tb,struct rtmsg ** rtm,struct mctp_dev ** mdev,mctp_eid_t * daddr_start)1202 static int mctp_route_nlparse(struct sk_buff *skb, struct nlmsghdr *nlh,
1203 			      struct netlink_ext_ack *extack,
1204 			      struct nlattr **tb, struct rtmsg **rtm,
1205 			      struct mctp_dev **mdev, mctp_eid_t *daddr_start)
1206 {
1207 	struct net *net = sock_net(skb->sk);
1208 	struct net_device *dev;
1209 	unsigned int ifindex;
1210 	int rc;
1211 
1212 	rc = nlmsg_parse(nlh, sizeof(struct rtmsg), tb, RTA_MAX,
1213 			 rta_mctp_policy, extack);
1214 	if (rc < 0) {
1215 		NL_SET_ERR_MSG(extack, "incorrect format");
1216 		return rc;
1217 	}
1218 
1219 	if (!tb[RTA_DST]) {
1220 		NL_SET_ERR_MSG(extack, "dst EID missing");
1221 		return -EINVAL;
1222 	}
1223 	*daddr_start = nla_get_u8(tb[RTA_DST]);
1224 
1225 	if (!tb[RTA_OIF]) {
1226 		NL_SET_ERR_MSG(extack, "ifindex missing");
1227 		return -EINVAL;
1228 	}
1229 	ifindex = nla_get_u32(tb[RTA_OIF]);
1230 
1231 	*rtm = nlmsg_data(nlh);
1232 	if ((*rtm)->rtm_family != AF_MCTP) {
1233 		NL_SET_ERR_MSG(extack, "route family must be AF_MCTP");
1234 		return -EINVAL;
1235 	}
1236 
1237 	dev = __dev_get_by_index(net, ifindex);
1238 	if (!dev) {
1239 		NL_SET_ERR_MSG(extack, "bad ifindex");
1240 		return -ENODEV;
1241 	}
1242 	*mdev = mctp_dev_get_rtnl(dev);
1243 	if (!*mdev)
1244 		return -ENODEV;
1245 
1246 	if (dev->flags & IFF_LOOPBACK) {
1247 		NL_SET_ERR_MSG(extack, "no routes to loopback");
1248 		return -EINVAL;
1249 	}
1250 
1251 	return 0;
1252 }
1253 
1254 static const struct nla_policy rta_metrics_policy[RTAX_MAX + 1] = {
1255 	[RTAX_MTU]		= { .type = NLA_U32 },
1256 };
1257 
mctp_newroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)1258 static int mctp_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
1259 			 struct netlink_ext_ack *extack)
1260 {
1261 	struct nlattr *tb[RTA_MAX + 1];
1262 	struct nlattr *tbx[RTAX_MAX + 1];
1263 	mctp_eid_t daddr_start;
1264 	struct mctp_dev *mdev;
1265 	struct rtmsg *rtm;
1266 	unsigned int mtu;
1267 	int rc;
1268 
1269 	rc = mctp_route_nlparse(skb, nlh, extack, tb,
1270 				&rtm, &mdev, &daddr_start);
1271 	if (rc < 0)
1272 		return rc;
1273 
1274 	if (rtm->rtm_type != RTN_UNICAST) {
1275 		NL_SET_ERR_MSG(extack, "rtm_type must be RTN_UNICAST");
1276 		return -EINVAL;
1277 	}
1278 
1279 	mtu = 0;
1280 	if (tb[RTA_METRICS]) {
1281 		rc = nla_parse_nested(tbx, RTAX_MAX, tb[RTA_METRICS],
1282 				      rta_metrics_policy, NULL);
1283 		if (rc < 0)
1284 			return rc;
1285 		if (tbx[RTAX_MTU])
1286 			mtu = nla_get_u32(tbx[RTAX_MTU]);
1287 	}
1288 
1289 	rc = mctp_route_add(mdev, daddr_start, rtm->rtm_dst_len, mtu,
1290 			    rtm->rtm_type);
1291 	return rc;
1292 }
1293 
mctp_delroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)1294 static int mctp_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
1295 			 struct netlink_ext_ack *extack)
1296 {
1297 	struct nlattr *tb[RTA_MAX + 1];
1298 	mctp_eid_t daddr_start;
1299 	struct mctp_dev *mdev;
1300 	struct rtmsg *rtm;
1301 	int rc;
1302 
1303 	rc = mctp_route_nlparse(skb, nlh, extack, tb,
1304 				&rtm, &mdev, &daddr_start);
1305 	if (rc < 0)
1306 		return rc;
1307 
1308 	/* we only have unicast routes */
1309 	if (rtm->rtm_type != RTN_UNICAST)
1310 		return -EINVAL;
1311 
1312 	rc = mctp_route_remove(mdev, daddr_start, rtm->rtm_dst_len, RTN_UNICAST);
1313 	return rc;
1314 }
1315 
mctp_fill_rtinfo(struct sk_buff * skb,struct mctp_route * rt,u32 portid,u32 seq,int event,unsigned int flags)1316 static int mctp_fill_rtinfo(struct sk_buff *skb, struct mctp_route *rt,
1317 			    u32 portid, u32 seq, int event, unsigned int flags)
1318 {
1319 	struct nlmsghdr *nlh;
1320 	struct rtmsg *hdr;
1321 	void *metrics;
1322 
1323 	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*hdr), flags);
1324 	if (!nlh)
1325 		return -EMSGSIZE;
1326 
1327 	hdr = nlmsg_data(nlh);
1328 	hdr->rtm_family = AF_MCTP;
1329 
1330 	/* we use the _len fields as a number of EIDs, rather than
1331 	 * a number of bits in the address
1332 	 */
1333 	hdr->rtm_dst_len = rt->max - rt->min;
1334 	hdr->rtm_src_len = 0;
1335 	hdr->rtm_tos = 0;
1336 	hdr->rtm_table = RT_TABLE_DEFAULT;
1337 	hdr->rtm_protocol = RTPROT_STATIC; /* everything is user-defined */
1338 	hdr->rtm_scope = RT_SCOPE_LINK; /* TODO: scope in mctp_route? */
1339 	hdr->rtm_type = rt->type;
1340 
1341 	if (nla_put_u8(skb, RTA_DST, rt->min))
1342 		goto cancel;
1343 
1344 	metrics = nla_nest_start_noflag(skb, RTA_METRICS);
1345 	if (!metrics)
1346 		goto cancel;
1347 
1348 	if (rt->mtu) {
1349 		if (nla_put_u32(skb, RTAX_MTU, rt->mtu))
1350 			goto cancel;
1351 	}
1352 
1353 	nla_nest_end(skb, metrics);
1354 
1355 	if (rt->dev) {
1356 		if (nla_put_u32(skb, RTA_OIF, rt->dev->dev->ifindex))
1357 			goto cancel;
1358 	}
1359 
1360 	/* TODO: conditional neighbour physaddr? */
1361 
1362 	nlmsg_end(skb, nlh);
1363 
1364 	return 0;
1365 
1366 cancel:
1367 	nlmsg_cancel(skb, nlh);
1368 	return -EMSGSIZE;
1369 }
1370 
mctp_dump_rtinfo(struct sk_buff * skb,struct netlink_callback * cb)1371 static int mctp_dump_rtinfo(struct sk_buff *skb, struct netlink_callback *cb)
1372 {
1373 	struct net *net = sock_net(skb->sk);
1374 	struct mctp_route *rt;
1375 	int s_idx, idx;
1376 
1377 	/* TODO: allow filtering on route data, possibly under
1378 	 * cb->strict_check
1379 	 */
1380 
1381 	/* TODO: change to struct overlay */
1382 	s_idx = cb->args[0];
1383 	idx = 0;
1384 
1385 	rcu_read_lock();
1386 	list_for_each_entry_rcu(rt, &net->mctp.routes, list) {
1387 		if (idx++ < s_idx)
1388 			continue;
1389 		if (mctp_fill_rtinfo(skb, rt,
1390 				     NETLINK_CB(cb->skb).portid,
1391 				     cb->nlh->nlmsg_seq,
1392 				     RTM_NEWROUTE, NLM_F_MULTI) < 0)
1393 			break;
1394 	}
1395 
1396 	rcu_read_unlock();
1397 	cb->args[0] = idx;
1398 
1399 	return skb->len;
1400 }
1401 
1402 /* net namespace implementation */
mctp_routes_net_init(struct net * net)1403 static int __net_init mctp_routes_net_init(struct net *net)
1404 {
1405 	struct netns_mctp *ns = &net->mctp;
1406 
1407 	INIT_LIST_HEAD(&ns->routes);
1408 	INIT_HLIST_HEAD(&ns->binds);
1409 	mutex_init(&ns->bind_lock);
1410 	INIT_HLIST_HEAD(&ns->keys);
1411 	spin_lock_init(&ns->keys_lock);
1412 	WARN_ON(mctp_default_net_set(net, MCTP_INITIAL_DEFAULT_NET));
1413 	return 0;
1414 }
1415 
mctp_routes_net_exit(struct net * net)1416 static void __net_exit mctp_routes_net_exit(struct net *net)
1417 {
1418 	struct mctp_route *rt;
1419 
1420 	rcu_read_lock();
1421 	list_for_each_entry_rcu(rt, &net->mctp.routes, list)
1422 		mctp_route_release(rt);
1423 	rcu_read_unlock();
1424 }
1425 
1426 static struct pernet_operations mctp_net_ops = {
1427 	.init = mctp_routes_net_init,
1428 	.exit = mctp_routes_net_exit,
1429 };
1430 
1431 static const struct rtnl_msg_handler mctp_route_rtnl_msg_handlers[] = {
1432 	{THIS_MODULE, PF_MCTP, RTM_NEWROUTE, mctp_newroute, NULL, 0},
1433 	{THIS_MODULE, PF_MCTP, RTM_DELROUTE, mctp_delroute, NULL, 0},
1434 	{THIS_MODULE, PF_MCTP, RTM_GETROUTE, NULL, mctp_dump_rtinfo, 0},
1435 };
1436 
mctp_routes_init(void)1437 int __init mctp_routes_init(void)
1438 {
1439 	int err;
1440 
1441 	dev_add_pack(&mctp_packet_type);
1442 
1443 	err = register_pernet_subsys(&mctp_net_ops);
1444 	if (err)
1445 		goto err_pernet;
1446 
1447 	err = rtnl_register_many(mctp_route_rtnl_msg_handlers);
1448 	if (err)
1449 		goto err_rtnl;
1450 
1451 	return 0;
1452 
1453 err_rtnl:
1454 	unregister_pernet_subsys(&mctp_net_ops);
1455 err_pernet:
1456 	dev_remove_pack(&mctp_packet_type);
1457 	return err;
1458 }
1459 
mctp_routes_exit(void)1460 void mctp_routes_exit(void)
1461 {
1462 	rtnl_unregister_many(mctp_route_rtnl_msg_handlers);
1463 	unregister_pernet_subsys(&mctp_net_ops);
1464 	dev_remove_pack(&mctp_packet_type);
1465 }
1466 
1467 #if IS_ENABLED(CONFIG_MCTP_TEST)
1468 #include "test/route-test.c"
1469 #endif
1470