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 (WARN_ON(key->dev && key->dev != dev))
278 		return;
279 
280 	mctp_dev_set_key(dev, key);
281 }
282 #else
mctp_skb_set_flow(struct sk_buff * skb,struct mctp_sk_key * key)283 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)284 static void mctp_flow_prepare_output(struct sk_buff *skb, struct mctp_dev *dev) {}
285 #endif
286 
mctp_frag_queue(struct mctp_sk_key * key,struct sk_buff * skb)287 static int mctp_frag_queue(struct mctp_sk_key *key, struct sk_buff *skb)
288 {
289 	struct mctp_hdr *hdr = mctp_hdr(skb);
290 	u8 exp_seq, this_seq;
291 
292 	this_seq = (hdr->flags_seq_tag >> MCTP_HDR_SEQ_SHIFT)
293 		& MCTP_HDR_SEQ_MASK;
294 
295 	if (!key->reasm_head) {
296 		key->reasm_head = skb;
297 		key->reasm_tailp = &(skb_shinfo(skb)->frag_list);
298 		key->last_seq = this_seq;
299 		return 0;
300 	}
301 
302 	exp_seq = (key->last_seq + 1) & MCTP_HDR_SEQ_MASK;
303 
304 	if (this_seq != exp_seq)
305 		return -EINVAL;
306 
307 	if (key->reasm_head->len + skb->len > mctp_message_maxlen)
308 		return -EINVAL;
309 
310 	skb->next = NULL;
311 	skb->sk = NULL;
312 	*key->reasm_tailp = skb;
313 	key->reasm_tailp = &skb->next;
314 
315 	key->last_seq = this_seq;
316 
317 	key->reasm_head->data_len += skb->len;
318 	key->reasm_head->len += skb->len;
319 	key->reasm_head->truesize += skb->truesize;
320 
321 	return 0;
322 }
323 
mctp_route_input(struct mctp_route * route,struct sk_buff * skb)324 static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb)
325 {
326 	struct mctp_sk_key *key, *any_key = NULL;
327 	struct net *net = dev_net(skb->dev);
328 	struct mctp_sock *msk;
329 	struct mctp_hdr *mh;
330 	unsigned long f;
331 	u8 tag, flags;
332 	int rc;
333 
334 	msk = NULL;
335 	rc = -EINVAL;
336 
337 	/* we may be receiving a locally-routed packet; drop source sk
338 	 * accounting
339 	 */
340 	skb_orphan(skb);
341 
342 	/* ensure we have enough data for a header and a type */
343 	if (skb->len < sizeof(struct mctp_hdr) + 1)
344 		goto out;
345 
346 	/* grab header, advance data ptr */
347 	mh = mctp_hdr(skb);
348 	skb_pull(skb, sizeof(struct mctp_hdr));
349 
350 	if (mh->ver != 1)
351 		goto out;
352 
353 	flags = mh->flags_seq_tag & (MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM);
354 	tag = mh->flags_seq_tag & (MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO);
355 
356 	rcu_read_lock();
357 
358 	/* lookup socket / reasm context, exactly matching (src,dest,tag).
359 	 * we hold a ref on the key, and key->lock held.
360 	 */
361 	key = mctp_lookup_key(net, skb, mh->src, &f);
362 
363 	if (flags & MCTP_HDR_FLAG_SOM) {
364 		if (key) {
365 			msk = container_of(key->sk, struct mctp_sock, sk);
366 		} else {
367 			/* first response to a broadcast? do a more general
368 			 * key lookup to find the socket, but don't use this
369 			 * key for reassembly - we'll create a more specific
370 			 * one for future packets if required (ie, !EOM).
371 			 */
372 			any_key = mctp_lookup_key(net, skb, MCTP_ADDR_ANY, &f);
373 			if (any_key) {
374 				msk = container_of(any_key->sk,
375 						   struct mctp_sock, sk);
376 				spin_unlock_irqrestore(&any_key->lock, f);
377 			}
378 		}
379 
380 		if (!key && !msk && (tag & MCTP_HDR_FLAG_TO))
381 			msk = mctp_lookup_bind(net, skb);
382 
383 		if (!msk) {
384 			rc = -ENOENT;
385 			goto out_unlock;
386 		}
387 
388 		/* single-packet message? deliver to socket, clean up any
389 		 * pending key.
390 		 */
391 		if (flags & MCTP_HDR_FLAG_EOM) {
392 			sock_queue_rcv_skb(&msk->sk, skb);
393 			if (key) {
394 				/* we've hit a pending reassembly; not much we
395 				 * can do but drop it
396 				 */
397 				__mctp_key_done_in(key, net, f,
398 						   MCTP_TRACE_KEY_REPLIED);
399 				key = NULL;
400 			}
401 			rc = 0;
402 			goto out_unlock;
403 		}
404 
405 		/* broadcast response or a bind() - create a key for further
406 		 * packets for this message
407 		 */
408 		if (!key) {
409 			key = mctp_key_alloc(msk, mh->dest, mh->src,
410 					     tag, GFP_ATOMIC);
411 			if (!key) {
412 				rc = -ENOMEM;
413 				goto out_unlock;
414 			}
415 
416 			/* we can queue without the key lock here, as the
417 			 * key isn't observable yet
418 			 */
419 			mctp_frag_queue(key, skb);
420 
421 			/* if the key_add fails, we've raced with another
422 			 * SOM packet with the same src, dest and tag. There's
423 			 * no way to distinguish future packets, so all we
424 			 * can do is drop; we'll free the skb on exit from
425 			 * this function.
426 			 */
427 			rc = mctp_key_add(key, msk);
428 			if (!rc)
429 				trace_mctp_key_acquire(key);
430 
431 			/* we don't need to release key->lock on exit, so
432 			 * clean up here and suppress the unlock via
433 			 * setting to NULL
434 			 */
435 			mctp_key_unref(key);
436 			key = NULL;
437 
438 		} else {
439 			if (key->reasm_head || key->reasm_dead) {
440 				/* duplicate start? drop everything */
441 				__mctp_key_done_in(key, net, f,
442 						   MCTP_TRACE_KEY_INVALIDATED);
443 				rc = -EEXIST;
444 				key = NULL;
445 			} else {
446 				rc = mctp_frag_queue(key, skb);
447 			}
448 		}
449 
450 	} else if (key) {
451 		/* this packet continues a previous message; reassemble
452 		 * using the message-specific key
453 		 */
454 
455 		/* we need to be continuing an existing reassembly... */
456 		if (!key->reasm_head)
457 			rc = -EINVAL;
458 		else
459 			rc = mctp_frag_queue(key, skb);
460 
461 		/* end of message? deliver to socket, and we're done with
462 		 * the reassembly/response key
463 		 */
464 		if (!rc && flags & MCTP_HDR_FLAG_EOM) {
465 			sock_queue_rcv_skb(key->sk, key->reasm_head);
466 			key->reasm_head = NULL;
467 			__mctp_key_done_in(key, net, f, MCTP_TRACE_KEY_REPLIED);
468 			key = NULL;
469 		}
470 
471 	} else {
472 		/* not a start, no matching key */
473 		rc = -ENOENT;
474 	}
475 
476 out_unlock:
477 	rcu_read_unlock();
478 	if (key) {
479 		spin_unlock_irqrestore(&key->lock, f);
480 		mctp_key_unref(key);
481 	}
482 	if (any_key)
483 		mctp_key_unref(any_key);
484 out:
485 	if (rc)
486 		kfree_skb(skb);
487 	return rc;
488 }
489 
mctp_route_mtu(struct mctp_route * rt)490 static unsigned int mctp_route_mtu(struct mctp_route *rt)
491 {
492 	return rt->mtu ?: READ_ONCE(rt->dev->dev->mtu);
493 }
494 
mctp_route_output(struct mctp_route * route,struct sk_buff * skb)495 static int mctp_route_output(struct mctp_route *route, struct sk_buff *skb)
496 {
497 	struct mctp_skb_cb *cb = mctp_cb(skb);
498 	struct mctp_hdr *hdr = mctp_hdr(skb);
499 	char daddr_buf[MAX_ADDR_LEN];
500 	char *daddr = NULL;
501 	unsigned int mtu;
502 	int rc;
503 
504 	skb->protocol = htons(ETH_P_MCTP);
505 
506 	mtu = READ_ONCE(skb->dev->mtu);
507 	if (skb->len > mtu) {
508 		kfree_skb(skb);
509 		return -EMSGSIZE;
510 	}
511 
512 	if (cb->ifindex) {
513 		/* direct route; use the hwaddr we stashed in sendmsg */
514 		if (cb->halen != skb->dev->addr_len) {
515 			/* sanity check, sendmsg should have already caught this */
516 			kfree_skb(skb);
517 			return -EMSGSIZE;
518 		}
519 		daddr = cb->haddr;
520 	} else {
521 		/* If lookup fails let the device handle daddr==NULL */
522 		if (mctp_neigh_lookup(route->dev, hdr->dest, daddr_buf) == 0)
523 			daddr = daddr_buf;
524 	}
525 
526 	rc = dev_hard_header(skb, skb->dev, ntohs(skb->protocol),
527 			     daddr, skb->dev->dev_addr, skb->len);
528 	if (rc < 0) {
529 		kfree_skb(skb);
530 		return -EHOSTUNREACH;
531 	}
532 
533 	mctp_flow_prepare_output(skb, route->dev);
534 
535 	rc = dev_queue_xmit(skb);
536 	if (rc)
537 		rc = net_xmit_errno(rc);
538 
539 	return rc;
540 }
541 
542 /* route alloc/release */
mctp_route_release(struct mctp_route * rt)543 static void mctp_route_release(struct mctp_route *rt)
544 {
545 	if (refcount_dec_and_test(&rt->refs)) {
546 		mctp_dev_put(rt->dev);
547 		kfree_rcu(rt, rcu);
548 	}
549 }
550 
551 /* returns a route with the refcount at 1 */
mctp_route_alloc(void)552 static struct mctp_route *mctp_route_alloc(void)
553 {
554 	struct mctp_route *rt;
555 
556 	rt = kzalloc(sizeof(*rt), GFP_KERNEL);
557 	if (!rt)
558 		return NULL;
559 
560 	INIT_LIST_HEAD(&rt->list);
561 	refcount_set(&rt->refs, 1);
562 	rt->output = mctp_route_discard;
563 
564 	return rt;
565 }
566 
mctp_default_net(struct net * net)567 unsigned int mctp_default_net(struct net *net)
568 {
569 	return READ_ONCE(net->mctp.default_net);
570 }
571 
mctp_default_net_set(struct net * net,unsigned int index)572 int mctp_default_net_set(struct net *net, unsigned int index)
573 {
574 	if (index == 0)
575 		return -EINVAL;
576 	WRITE_ONCE(net->mctp.default_net, index);
577 	return 0;
578 }
579 
580 /* tag management */
mctp_reserve_tag(struct net * net,struct mctp_sk_key * key,struct mctp_sock * msk)581 static void mctp_reserve_tag(struct net *net, struct mctp_sk_key *key,
582 			     struct mctp_sock *msk)
583 {
584 	struct netns_mctp *mns = &net->mctp;
585 
586 	lockdep_assert_held(&mns->keys_lock);
587 
588 	key->expiry = jiffies + mctp_key_lifetime;
589 	timer_reduce(&msk->key_expiry, key->expiry);
590 
591 	/* we hold the net->key_lock here, allowing updates to both
592 	 * then net and sk
593 	 */
594 	hlist_add_head_rcu(&key->hlist, &mns->keys);
595 	hlist_add_head_rcu(&key->sklist, &msk->keys);
596 	refcount_inc(&key->refs);
597 }
598 
599 /* Allocate a locally-owned tag value for (saddr, daddr), and reserve
600  * it for the socket msk
601  */
mctp_alloc_local_tag(struct mctp_sock * msk,mctp_eid_t daddr,mctp_eid_t saddr,bool manual,u8 * tagp)602 struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk,
603 					 mctp_eid_t daddr, mctp_eid_t saddr,
604 					 bool manual, u8 *tagp)
605 {
606 	struct net *net = sock_net(&msk->sk);
607 	struct netns_mctp *mns = &net->mctp;
608 	struct mctp_sk_key *key, *tmp;
609 	unsigned long flags;
610 	u8 tagbits;
611 
612 	/* for NULL destination EIDs, we may get a response from any peer */
613 	if (daddr == MCTP_ADDR_NULL)
614 		daddr = MCTP_ADDR_ANY;
615 
616 	/* be optimistic, alloc now */
617 	key = mctp_key_alloc(msk, saddr, daddr, 0, GFP_KERNEL);
618 	if (!key)
619 		return ERR_PTR(-ENOMEM);
620 
621 	/* 8 possible tag values */
622 	tagbits = 0xff;
623 
624 	spin_lock_irqsave(&mns->keys_lock, flags);
625 
626 	/* Walk through the existing keys, looking for potential conflicting
627 	 * tags. If we find a conflict, clear that bit from tagbits
628 	 */
629 	hlist_for_each_entry(tmp, &mns->keys, hlist) {
630 		/* We can check the lookup fields (*_addr, tag) without the
631 		 * lock held, they don't change over the lifetime of the key.
632 		 */
633 
634 		/* if we don't own the tag, it can't conflict */
635 		if (tmp->tag & MCTP_HDR_FLAG_TO)
636 			continue;
637 
638 		if (!(mctp_address_matches(tmp->peer_addr, daddr) &&
639 		      mctp_address_matches(tmp->local_addr, saddr)))
640 			continue;
641 
642 		spin_lock(&tmp->lock);
643 		/* key must still be valid. If we find a match, clear the
644 		 * potential tag value
645 		 */
646 		if (tmp->valid)
647 			tagbits &= ~(1 << tmp->tag);
648 		spin_unlock(&tmp->lock);
649 
650 		if (!tagbits)
651 			break;
652 	}
653 
654 	if (tagbits) {
655 		key->tag = __ffs(tagbits);
656 		mctp_reserve_tag(net, key, msk);
657 		trace_mctp_key_acquire(key);
658 
659 		key->manual_alloc = manual;
660 		*tagp = key->tag;
661 	}
662 
663 	spin_unlock_irqrestore(&mns->keys_lock, flags);
664 
665 	if (!tagbits) {
666 		kfree(key);
667 		return ERR_PTR(-EBUSY);
668 	}
669 
670 	return key;
671 }
672 
mctp_lookup_prealloc_tag(struct mctp_sock * msk,mctp_eid_t daddr,u8 req_tag,u8 * tagp)673 static struct mctp_sk_key *mctp_lookup_prealloc_tag(struct mctp_sock *msk,
674 						    mctp_eid_t daddr,
675 						    u8 req_tag, u8 *tagp)
676 {
677 	struct net *net = sock_net(&msk->sk);
678 	struct netns_mctp *mns = &net->mctp;
679 	struct mctp_sk_key *key, *tmp;
680 	unsigned long flags;
681 
682 	req_tag &= ~(MCTP_TAG_PREALLOC | MCTP_TAG_OWNER);
683 	key = NULL;
684 
685 	spin_lock_irqsave(&mns->keys_lock, flags);
686 
687 	hlist_for_each_entry(tmp, &mns->keys, hlist) {
688 		if (tmp->tag != req_tag)
689 			continue;
690 
691 		if (!mctp_address_matches(tmp->peer_addr, daddr))
692 			continue;
693 
694 		if (!tmp->manual_alloc)
695 			continue;
696 
697 		spin_lock(&tmp->lock);
698 		if (tmp->valid) {
699 			key = tmp;
700 			refcount_inc(&key->refs);
701 			spin_unlock(&tmp->lock);
702 			break;
703 		}
704 		spin_unlock(&tmp->lock);
705 	}
706 	spin_unlock_irqrestore(&mns->keys_lock, flags);
707 
708 	if (!key)
709 		return ERR_PTR(-ENOENT);
710 
711 	if (tagp)
712 		*tagp = key->tag;
713 
714 	return key;
715 }
716 
717 /* routing lookups */
mctp_rt_match_eid(struct mctp_route * rt,unsigned int net,mctp_eid_t eid)718 static bool mctp_rt_match_eid(struct mctp_route *rt,
719 			      unsigned int net, mctp_eid_t eid)
720 {
721 	return READ_ONCE(rt->dev->net) == net &&
722 		rt->min <= eid && rt->max >= eid;
723 }
724 
725 /* compares match, used for duplicate prevention */
mctp_rt_compare_exact(struct mctp_route * rt1,struct mctp_route * rt2)726 static bool mctp_rt_compare_exact(struct mctp_route *rt1,
727 				  struct mctp_route *rt2)
728 {
729 	ASSERT_RTNL();
730 	return rt1->dev->net == rt2->dev->net &&
731 		rt1->min == rt2->min &&
732 		rt1->max == rt2->max;
733 }
734 
mctp_route_lookup(struct net * net,unsigned int dnet,mctp_eid_t daddr)735 struct mctp_route *mctp_route_lookup(struct net *net, unsigned int dnet,
736 				     mctp_eid_t daddr)
737 {
738 	struct mctp_route *tmp, *rt = NULL;
739 
740 	list_for_each_entry_rcu(tmp, &net->mctp.routes, list) {
741 		/* TODO: add metrics */
742 		if (mctp_rt_match_eid(tmp, dnet, daddr)) {
743 			if (refcount_inc_not_zero(&tmp->refs)) {
744 				rt = tmp;
745 				break;
746 			}
747 		}
748 	}
749 
750 	return rt;
751 }
752 
mctp_route_lookup_null(struct net * net,struct net_device * dev)753 static struct mctp_route *mctp_route_lookup_null(struct net *net,
754 						 struct net_device *dev)
755 {
756 	struct mctp_route *rt;
757 
758 	list_for_each_entry_rcu(rt, &net->mctp.routes, list) {
759 		if (rt->dev->dev == dev && rt->type == RTN_LOCAL &&
760 		    refcount_inc_not_zero(&rt->refs))
761 			return rt;
762 	}
763 
764 	return NULL;
765 }
766 
mctp_do_fragment_route(struct mctp_route * rt,struct sk_buff * skb,unsigned int mtu,u8 tag)767 static int mctp_do_fragment_route(struct mctp_route *rt, struct sk_buff *skb,
768 				  unsigned int mtu, u8 tag)
769 {
770 	const unsigned int hlen = sizeof(struct mctp_hdr);
771 	struct mctp_hdr *hdr, *hdr2;
772 	unsigned int pos, size, headroom;
773 	struct sk_buff *skb2;
774 	int rc;
775 	u8 seq;
776 
777 	hdr = mctp_hdr(skb);
778 	seq = 0;
779 	rc = 0;
780 
781 	if (mtu < hlen + 1) {
782 		kfree_skb(skb);
783 		return -EMSGSIZE;
784 	}
785 
786 	/* keep same headroom as the original skb */
787 	headroom = skb_headroom(skb);
788 
789 	/* we've got the header */
790 	skb_pull(skb, hlen);
791 
792 	for (pos = 0; pos < skb->len;) {
793 		/* size of message payload */
794 		size = min(mtu - hlen, skb->len - pos);
795 
796 		skb2 = alloc_skb(headroom + hlen + size, GFP_KERNEL);
797 		if (!skb2) {
798 			rc = -ENOMEM;
799 			break;
800 		}
801 
802 		/* generic skb copy */
803 		skb2->protocol = skb->protocol;
804 		skb2->priority = skb->priority;
805 		skb2->dev = skb->dev;
806 		memcpy(skb2->cb, skb->cb, sizeof(skb2->cb));
807 
808 		if (skb->sk)
809 			skb_set_owner_w(skb2, skb->sk);
810 
811 		/* establish packet */
812 		skb_reserve(skb2, headroom);
813 		skb_reset_network_header(skb2);
814 		skb_put(skb2, hlen + size);
815 		skb2->transport_header = skb2->network_header + hlen;
816 
817 		/* copy header fields, calculate SOM/EOM flags & seq */
818 		hdr2 = mctp_hdr(skb2);
819 		hdr2->ver = hdr->ver;
820 		hdr2->dest = hdr->dest;
821 		hdr2->src = hdr->src;
822 		hdr2->flags_seq_tag = tag &
823 			(MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO);
824 
825 		if (pos == 0)
826 			hdr2->flags_seq_tag |= MCTP_HDR_FLAG_SOM;
827 
828 		if (pos + size == skb->len)
829 			hdr2->flags_seq_tag |= MCTP_HDR_FLAG_EOM;
830 
831 		hdr2->flags_seq_tag |= seq << MCTP_HDR_SEQ_SHIFT;
832 
833 		/* copy message payload */
834 		skb_copy_bits(skb, pos, skb_transport_header(skb2), size);
835 
836 		/* do route */
837 		rc = rt->output(rt, skb2);
838 		if (rc)
839 			break;
840 
841 		seq = (seq + 1) & MCTP_HDR_SEQ_MASK;
842 		pos += size;
843 	}
844 
845 	consume_skb(skb);
846 	return rc;
847 }
848 
mctp_local_output(struct sock * sk,struct mctp_route * rt,struct sk_buff * skb,mctp_eid_t daddr,u8 req_tag)849 int mctp_local_output(struct sock *sk, struct mctp_route *rt,
850 		      struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag)
851 {
852 	struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);
853 	struct mctp_skb_cb *cb = mctp_cb(skb);
854 	struct mctp_route tmp_rt = {0};
855 	struct mctp_sk_key *key;
856 	struct mctp_hdr *hdr;
857 	unsigned long flags;
858 	unsigned int mtu;
859 	mctp_eid_t saddr;
860 	bool ext_rt;
861 	int rc;
862 	u8 tag;
863 
864 	rc = -ENODEV;
865 
866 	if (rt) {
867 		ext_rt = false;
868 		if (WARN_ON(!rt->dev))
869 			goto out_release;
870 
871 	} else if (cb->ifindex) {
872 		struct net_device *dev;
873 
874 		ext_rt = true;
875 		rt = &tmp_rt;
876 
877 		rcu_read_lock();
878 		dev = dev_get_by_index_rcu(sock_net(sk), cb->ifindex);
879 		if (!dev) {
880 			rcu_read_unlock();
881 			return rc;
882 		}
883 		rt->dev = __mctp_dev_get(dev);
884 		rcu_read_unlock();
885 
886 		if (!rt->dev)
887 			goto out_release;
888 
889 		/* establish temporary route - we set up enough to keep
890 		 * mctp_route_output happy
891 		 */
892 		rt->output = mctp_route_output;
893 		rt->mtu = 0;
894 
895 	} else {
896 		return -EINVAL;
897 	}
898 
899 	spin_lock_irqsave(&rt->dev->addrs_lock, flags);
900 	if (rt->dev->num_addrs == 0) {
901 		rc = -EHOSTUNREACH;
902 	} else {
903 		/* use the outbound interface's first address as our source */
904 		saddr = rt->dev->addrs[0];
905 		rc = 0;
906 	}
907 	spin_unlock_irqrestore(&rt->dev->addrs_lock, flags);
908 
909 	if (rc)
910 		goto out_release;
911 
912 	if (req_tag & MCTP_TAG_OWNER) {
913 		if (req_tag & MCTP_TAG_PREALLOC)
914 			key = mctp_lookup_prealloc_tag(msk, daddr,
915 						       req_tag, &tag);
916 		else
917 			key = mctp_alloc_local_tag(msk, daddr, saddr,
918 						   false, &tag);
919 
920 		if (IS_ERR(key)) {
921 			rc = PTR_ERR(key);
922 			goto out_release;
923 		}
924 		mctp_skb_set_flow(skb, key);
925 		/* done with the key in this scope */
926 		mctp_key_unref(key);
927 		tag |= MCTP_HDR_FLAG_TO;
928 	} else {
929 		key = NULL;
930 		tag = req_tag & MCTP_TAG_MASK;
931 	}
932 
933 	skb->protocol = htons(ETH_P_MCTP);
934 	skb->priority = 0;
935 	skb_reset_transport_header(skb);
936 	skb_push(skb, sizeof(struct mctp_hdr));
937 	skb_reset_network_header(skb);
938 	skb->dev = rt->dev->dev;
939 
940 	/* cb->net will have been set on initial ingress */
941 	cb->src = saddr;
942 
943 	/* set up common header fields */
944 	hdr = mctp_hdr(skb);
945 	hdr->ver = 1;
946 	hdr->dest = daddr;
947 	hdr->src = saddr;
948 
949 	mtu = mctp_route_mtu(rt);
950 
951 	if (skb->len + sizeof(struct mctp_hdr) <= mtu) {
952 		hdr->flags_seq_tag = MCTP_HDR_FLAG_SOM |
953 			MCTP_HDR_FLAG_EOM | tag;
954 		rc = rt->output(rt, skb);
955 	} else {
956 		rc = mctp_do_fragment_route(rt, skb, mtu, tag);
957 	}
958 
959 out_release:
960 	if (!ext_rt)
961 		mctp_route_release(rt);
962 
963 	mctp_dev_put(tmp_rt.dev);
964 
965 	return rc;
966 }
967 
968 /* route management */
mctp_route_add(struct mctp_dev * mdev,mctp_eid_t daddr_start,unsigned int daddr_extent,unsigned int mtu,unsigned char type)969 static int mctp_route_add(struct mctp_dev *mdev, mctp_eid_t daddr_start,
970 			  unsigned int daddr_extent, unsigned int mtu,
971 			  unsigned char type)
972 {
973 	int (*rtfn)(struct mctp_route *rt, struct sk_buff *skb);
974 	struct net *net = dev_net(mdev->dev);
975 	struct mctp_route *rt, *ert;
976 
977 	if (!mctp_address_unicast(daddr_start))
978 		return -EINVAL;
979 
980 	if (daddr_extent > 0xff || daddr_start + daddr_extent >= 255)
981 		return -EINVAL;
982 
983 	switch (type) {
984 	case RTN_LOCAL:
985 		rtfn = mctp_route_input;
986 		break;
987 	case RTN_UNICAST:
988 		rtfn = mctp_route_output;
989 		break;
990 	default:
991 		return -EINVAL;
992 	}
993 
994 	rt = mctp_route_alloc();
995 	if (!rt)
996 		return -ENOMEM;
997 
998 	rt->min = daddr_start;
999 	rt->max = daddr_start + daddr_extent;
1000 	rt->mtu = mtu;
1001 	rt->dev = mdev;
1002 	mctp_dev_hold(rt->dev);
1003 	rt->type = type;
1004 	rt->output = rtfn;
1005 
1006 	ASSERT_RTNL();
1007 	/* Prevent duplicate identical routes. */
1008 	list_for_each_entry(ert, &net->mctp.routes, list) {
1009 		if (mctp_rt_compare_exact(rt, ert)) {
1010 			mctp_route_release(rt);
1011 			return -EEXIST;
1012 		}
1013 	}
1014 
1015 	list_add_rcu(&rt->list, &net->mctp.routes);
1016 
1017 	return 0;
1018 }
1019 
mctp_route_remove(struct mctp_dev * mdev,mctp_eid_t daddr_start,unsigned int daddr_extent,unsigned char type)1020 static int mctp_route_remove(struct mctp_dev *mdev, mctp_eid_t daddr_start,
1021 			     unsigned int daddr_extent, unsigned char type)
1022 {
1023 	struct net *net = dev_net(mdev->dev);
1024 	struct mctp_route *rt, *tmp;
1025 	mctp_eid_t daddr_end;
1026 	bool dropped;
1027 
1028 	if (daddr_extent > 0xff || daddr_start + daddr_extent >= 255)
1029 		return -EINVAL;
1030 
1031 	daddr_end = daddr_start + daddr_extent;
1032 	dropped = false;
1033 
1034 	ASSERT_RTNL();
1035 
1036 	list_for_each_entry_safe(rt, tmp, &net->mctp.routes, list) {
1037 		if (rt->dev == mdev &&
1038 		    rt->min == daddr_start && rt->max == daddr_end &&
1039 		    rt->type == type) {
1040 			list_del_rcu(&rt->list);
1041 			/* TODO: immediate RTM_DELROUTE */
1042 			mctp_route_release(rt);
1043 			dropped = true;
1044 		}
1045 	}
1046 
1047 	return dropped ? 0 : -ENOENT;
1048 }
1049 
mctp_route_add_local(struct mctp_dev * mdev,mctp_eid_t addr)1050 int mctp_route_add_local(struct mctp_dev *mdev, mctp_eid_t addr)
1051 {
1052 	return mctp_route_add(mdev, addr, 0, 0, RTN_LOCAL);
1053 }
1054 
mctp_route_remove_local(struct mctp_dev * mdev,mctp_eid_t addr)1055 int mctp_route_remove_local(struct mctp_dev *mdev, mctp_eid_t addr)
1056 {
1057 	return mctp_route_remove(mdev, addr, 0, RTN_LOCAL);
1058 }
1059 
1060 /* removes all entries for a given device */
mctp_route_remove_dev(struct mctp_dev * mdev)1061 void mctp_route_remove_dev(struct mctp_dev *mdev)
1062 {
1063 	struct net *net = dev_net(mdev->dev);
1064 	struct mctp_route *rt, *tmp;
1065 
1066 	ASSERT_RTNL();
1067 	list_for_each_entry_safe(rt, tmp, &net->mctp.routes, list) {
1068 		if (rt->dev == mdev) {
1069 			list_del_rcu(&rt->list);
1070 			/* TODO: immediate RTM_DELROUTE */
1071 			mctp_route_release(rt);
1072 		}
1073 	}
1074 }
1075 
1076 /* Incoming packet-handling */
1077 
mctp_pkttype_receive(struct sk_buff * skb,struct net_device * dev,struct packet_type * pt,struct net_device * orig_dev)1078 static int mctp_pkttype_receive(struct sk_buff *skb, struct net_device *dev,
1079 				struct packet_type *pt,
1080 				struct net_device *orig_dev)
1081 {
1082 	struct net *net = dev_net(dev);
1083 	struct mctp_dev *mdev;
1084 	struct mctp_skb_cb *cb;
1085 	struct mctp_route *rt;
1086 	struct mctp_hdr *mh;
1087 
1088 	rcu_read_lock();
1089 	mdev = __mctp_dev_get(dev);
1090 	rcu_read_unlock();
1091 	if (!mdev) {
1092 		/* basic non-data sanity checks */
1093 		goto err_drop;
1094 	}
1095 
1096 	if (!pskb_may_pull(skb, sizeof(struct mctp_hdr)))
1097 		goto err_drop;
1098 
1099 	skb_reset_transport_header(skb);
1100 	skb_reset_network_header(skb);
1101 
1102 	/* We have enough for a header; decode and route */
1103 	mh = mctp_hdr(skb);
1104 	if (mh->ver < MCTP_VER_MIN || mh->ver > MCTP_VER_MAX)
1105 		goto err_drop;
1106 
1107 	/* source must be valid unicast or null; drop reserved ranges and
1108 	 * broadcast
1109 	 */
1110 	if (!(mctp_address_unicast(mh->src) || mctp_address_null(mh->src)))
1111 		goto err_drop;
1112 
1113 	/* dest address: as above, but allow broadcast */
1114 	if (!(mctp_address_unicast(mh->dest) || mctp_address_null(mh->dest) ||
1115 	      mctp_address_broadcast(mh->dest)))
1116 		goto err_drop;
1117 
1118 	/* MCTP drivers must populate halen/haddr */
1119 	if (dev->type == ARPHRD_MCTP) {
1120 		cb = mctp_cb(skb);
1121 	} else {
1122 		cb = __mctp_cb(skb);
1123 		cb->halen = 0;
1124 	}
1125 	cb->net = READ_ONCE(mdev->net);
1126 	cb->ifindex = dev->ifindex;
1127 
1128 	rt = mctp_route_lookup(net, cb->net, mh->dest);
1129 
1130 	/* NULL EID, but addressed to our physical address */
1131 	if (!rt && mh->dest == MCTP_ADDR_NULL && skb->pkt_type == PACKET_HOST)
1132 		rt = mctp_route_lookup_null(net, dev);
1133 
1134 	if (!rt)
1135 		goto err_drop;
1136 
1137 	rt->output(rt, skb);
1138 	mctp_route_release(rt);
1139 	mctp_dev_put(mdev);
1140 
1141 	return NET_RX_SUCCESS;
1142 
1143 err_drop:
1144 	kfree_skb(skb);
1145 	mctp_dev_put(mdev);
1146 	return NET_RX_DROP;
1147 }
1148 
1149 static struct packet_type mctp_packet_type = {
1150 	.type = cpu_to_be16(ETH_P_MCTP),
1151 	.func = mctp_pkttype_receive,
1152 };
1153 
1154 /* netlink interface */
1155 
1156 static const struct nla_policy rta_mctp_policy[RTA_MAX + 1] = {
1157 	[RTA_DST]		= { .type = NLA_U8 },
1158 	[RTA_METRICS]		= { .type = NLA_NESTED },
1159 	[RTA_OIF]		= { .type = NLA_U32 },
1160 };
1161 
1162 /* Common part for RTM_NEWROUTE and RTM_DELROUTE parsing.
1163  * tb must hold RTA_MAX+1 elements.
1164  */
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)1165 static int mctp_route_nlparse(struct sk_buff *skb, struct nlmsghdr *nlh,
1166 			      struct netlink_ext_ack *extack,
1167 			      struct nlattr **tb, struct rtmsg **rtm,
1168 			      struct mctp_dev **mdev, mctp_eid_t *daddr_start)
1169 {
1170 	struct net *net = sock_net(skb->sk);
1171 	struct net_device *dev;
1172 	unsigned int ifindex;
1173 	int rc;
1174 
1175 	rc = nlmsg_parse(nlh, sizeof(struct rtmsg), tb, RTA_MAX,
1176 			 rta_mctp_policy, extack);
1177 	if (rc < 0) {
1178 		NL_SET_ERR_MSG(extack, "incorrect format");
1179 		return rc;
1180 	}
1181 
1182 	if (!tb[RTA_DST]) {
1183 		NL_SET_ERR_MSG(extack, "dst EID missing");
1184 		return -EINVAL;
1185 	}
1186 	*daddr_start = nla_get_u8(tb[RTA_DST]);
1187 
1188 	if (!tb[RTA_OIF]) {
1189 		NL_SET_ERR_MSG(extack, "ifindex missing");
1190 		return -EINVAL;
1191 	}
1192 	ifindex = nla_get_u32(tb[RTA_OIF]);
1193 
1194 	*rtm = nlmsg_data(nlh);
1195 	if ((*rtm)->rtm_family != AF_MCTP) {
1196 		NL_SET_ERR_MSG(extack, "route family must be AF_MCTP");
1197 		return -EINVAL;
1198 	}
1199 
1200 	dev = __dev_get_by_index(net, ifindex);
1201 	if (!dev) {
1202 		NL_SET_ERR_MSG(extack, "bad ifindex");
1203 		return -ENODEV;
1204 	}
1205 	*mdev = mctp_dev_get_rtnl(dev);
1206 	if (!*mdev)
1207 		return -ENODEV;
1208 
1209 	if (dev->flags & IFF_LOOPBACK) {
1210 		NL_SET_ERR_MSG(extack, "no routes to loopback");
1211 		return -EINVAL;
1212 	}
1213 
1214 	return 0;
1215 }
1216 
1217 static const struct nla_policy rta_metrics_policy[RTAX_MAX + 1] = {
1218 	[RTAX_MTU]		= { .type = NLA_U32 },
1219 };
1220 
mctp_newroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)1221 static int mctp_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
1222 			 struct netlink_ext_ack *extack)
1223 {
1224 	struct nlattr *tb[RTA_MAX + 1];
1225 	struct nlattr *tbx[RTAX_MAX + 1];
1226 	mctp_eid_t daddr_start;
1227 	struct mctp_dev *mdev;
1228 	struct rtmsg *rtm;
1229 	unsigned int mtu;
1230 	int rc;
1231 
1232 	rc = mctp_route_nlparse(skb, nlh, extack, tb,
1233 				&rtm, &mdev, &daddr_start);
1234 	if (rc < 0)
1235 		return rc;
1236 
1237 	if (rtm->rtm_type != RTN_UNICAST) {
1238 		NL_SET_ERR_MSG(extack, "rtm_type must be RTN_UNICAST");
1239 		return -EINVAL;
1240 	}
1241 
1242 	mtu = 0;
1243 	if (tb[RTA_METRICS]) {
1244 		rc = nla_parse_nested(tbx, RTAX_MAX, tb[RTA_METRICS],
1245 				      rta_metrics_policy, NULL);
1246 		if (rc < 0)
1247 			return rc;
1248 		if (tbx[RTAX_MTU])
1249 			mtu = nla_get_u32(tbx[RTAX_MTU]);
1250 	}
1251 
1252 	if (rtm->rtm_type != RTN_UNICAST)
1253 		return -EINVAL;
1254 
1255 	rc = mctp_route_add(mdev, daddr_start, rtm->rtm_dst_len, mtu,
1256 			    rtm->rtm_type);
1257 	return rc;
1258 }
1259 
mctp_delroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)1260 static int mctp_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
1261 			 struct netlink_ext_ack *extack)
1262 {
1263 	struct nlattr *tb[RTA_MAX + 1];
1264 	mctp_eid_t daddr_start;
1265 	struct mctp_dev *mdev;
1266 	struct rtmsg *rtm;
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 	/* we only have unicast routes */
1275 	if (rtm->rtm_type != RTN_UNICAST)
1276 		return -EINVAL;
1277 
1278 	rc = mctp_route_remove(mdev, daddr_start, rtm->rtm_dst_len, RTN_UNICAST);
1279 	return rc;
1280 }
1281 
mctp_fill_rtinfo(struct sk_buff * skb,struct mctp_route * rt,u32 portid,u32 seq,int event,unsigned int flags)1282 static int mctp_fill_rtinfo(struct sk_buff *skb, struct mctp_route *rt,
1283 			    u32 portid, u32 seq, int event, unsigned int flags)
1284 {
1285 	struct nlmsghdr *nlh;
1286 	struct rtmsg *hdr;
1287 	void *metrics;
1288 
1289 	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*hdr), flags);
1290 	if (!nlh)
1291 		return -EMSGSIZE;
1292 
1293 	hdr = nlmsg_data(nlh);
1294 	hdr->rtm_family = AF_MCTP;
1295 
1296 	/* we use the _len fields as a number of EIDs, rather than
1297 	 * a number of bits in the address
1298 	 */
1299 	hdr->rtm_dst_len = rt->max - rt->min;
1300 	hdr->rtm_src_len = 0;
1301 	hdr->rtm_tos = 0;
1302 	hdr->rtm_table = RT_TABLE_DEFAULT;
1303 	hdr->rtm_protocol = RTPROT_STATIC; /* everything is user-defined */
1304 	hdr->rtm_scope = RT_SCOPE_LINK; /* TODO: scope in mctp_route? */
1305 	hdr->rtm_type = rt->type;
1306 
1307 	if (nla_put_u8(skb, RTA_DST, rt->min))
1308 		goto cancel;
1309 
1310 	metrics = nla_nest_start_noflag(skb, RTA_METRICS);
1311 	if (!metrics)
1312 		goto cancel;
1313 
1314 	if (rt->mtu) {
1315 		if (nla_put_u32(skb, RTAX_MTU, rt->mtu))
1316 			goto cancel;
1317 	}
1318 
1319 	nla_nest_end(skb, metrics);
1320 
1321 	if (rt->dev) {
1322 		if (nla_put_u32(skb, RTA_OIF, rt->dev->dev->ifindex))
1323 			goto cancel;
1324 	}
1325 
1326 	/* TODO: conditional neighbour physaddr? */
1327 
1328 	nlmsg_end(skb, nlh);
1329 
1330 	return 0;
1331 
1332 cancel:
1333 	nlmsg_cancel(skb, nlh);
1334 	return -EMSGSIZE;
1335 }
1336 
mctp_dump_rtinfo(struct sk_buff * skb,struct netlink_callback * cb)1337 static int mctp_dump_rtinfo(struct sk_buff *skb, struct netlink_callback *cb)
1338 {
1339 	struct net *net = sock_net(skb->sk);
1340 	struct mctp_route *rt;
1341 	int s_idx, idx;
1342 
1343 	/* TODO: allow filtering on route data, possibly under
1344 	 * cb->strict_check
1345 	 */
1346 
1347 	/* TODO: change to struct overlay */
1348 	s_idx = cb->args[0];
1349 	idx = 0;
1350 
1351 	rcu_read_lock();
1352 	list_for_each_entry_rcu(rt, &net->mctp.routes, list) {
1353 		if (idx++ < s_idx)
1354 			continue;
1355 		if (mctp_fill_rtinfo(skb, rt,
1356 				     NETLINK_CB(cb->skb).portid,
1357 				     cb->nlh->nlmsg_seq,
1358 				     RTM_NEWROUTE, NLM_F_MULTI) < 0)
1359 			break;
1360 	}
1361 
1362 	rcu_read_unlock();
1363 	cb->args[0] = idx;
1364 
1365 	return skb->len;
1366 }
1367 
1368 /* net namespace implementation */
mctp_routes_net_init(struct net * net)1369 static int __net_init mctp_routes_net_init(struct net *net)
1370 {
1371 	struct netns_mctp *ns = &net->mctp;
1372 
1373 	INIT_LIST_HEAD(&ns->routes);
1374 	INIT_HLIST_HEAD(&ns->binds);
1375 	mutex_init(&ns->bind_lock);
1376 	INIT_HLIST_HEAD(&ns->keys);
1377 	spin_lock_init(&ns->keys_lock);
1378 	WARN_ON(mctp_default_net_set(net, MCTP_INITIAL_DEFAULT_NET));
1379 	return 0;
1380 }
1381 
mctp_routes_net_exit(struct net * net)1382 static void __net_exit mctp_routes_net_exit(struct net *net)
1383 {
1384 	struct mctp_route *rt;
1385 
1386 	rcu_read_lock();
1387 	list_for_each_entry_rcu(rt, &net->mctp.routes, list)
1388 		mctp_route_release(rt);
1389 	rcu_read_unlock();
1390 }
1391 
1392 static struct pernet_operations mctp_net_ops = {
1393 	.init = mctp_routes_net_init,
1394 	.exit = mctp_routes_net_exit,
1395 };
1396 
mctp_routes_init(void)1397 int __init mctp_routes_init(void)
1398 {
1399 	dev_add_pack(&mctp_packet_type);
1400 
1401 	rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_GETROUTE,
1402 			     NULL, mctp_dump_rtinfo, 0);
1403 	rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_NEWROUTE,
1404 			     mctp_newroute, NULL, 0);
1405 	rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_DELROUTE,
1406 			     mctp_delroute, NULL, 0);
1407 
1408 	return register_pernet_subsys(&mctp_net_ops);
1409 }
1410 
mctp_routes_exit(void)1411 void mctp_routes_exit(void)
1412 {
1413 	unregister_pernet_subsys(&mctp_net_ops);
1414 	rtnl_unregister(PF_MCTP, RTM_DELROUTE);
1415 	rtnl_unregister(PF_MCTP, RTM_NEWROUTE);
1416 	rtnl_unregister(PF_MCTP, RTM_GETROUTE);
1417 	dev_remove_pack(&mctp_packet_type);
1418 }
1419 
1420 #if IS_ENABLED(CONFIG_MCTP_TEST)
1421 #include "test/route-test.c"
1422 #endif
1423