xref: /openbmc/linux/net/mctp/route.c (revision 6f6249a599e52e1a5f0b632f8edff733cfa76450)
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 		/* Since we're manipulating the shared frag_list, ensure it isn't
299 		 * shared with any other SKBs.
300 		 */
301 		key->reasm_head = skb_unshare(skb, GFP_ATOMIC);
302 		if (!key->reasm_head)
303 			return -ENOMEM;
304 
305 		key->reasm_tailp = &(skb_shinfo(key->reasm_head)->frag_list);
306 		key->last_seq = this_seq;
307 		return 0;
308 	}
309 
310 	exp_seq = (key->last_seq + 1) & MCTP_HDR_SEQ_MASK;
311 
312 	if (this_seq != exp_seq)
313 		return -EINVAL;
314 
315 	if (key->reasm_head->len + skb->len > mctp_message_maxlen)
316 		return -EINVAL;
317 
318 	skb->next = NULL;
319 	skb->sk = NULL;
320 	*key->reasm_tailp = skb;
321 	key->reasm_tailp = &skb->next;
322 
323 	key->last_seq = this_seq;
324 
325 	key->reasm_head->data_len += skb->len;
326 	key->reasm_head->len += skb->len;
327 	key->reasm_head->truesize += skb->truesize;
328 
329 	return 0;
330 }
331 
mctp_route_input(struct mctp_route * route,struct sk_buff * skb)332 static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb)
333 {
334 	struct mctp_sk_key *key, *any_key = NULL;
335 	struct net *net = dev_net(skb->dev);
336 	struct mctp_sock *msk;
337 	struct mctp_hdr *mh;
338 	unsigned long f;
339 	u8 tag, flags;
340 	int rc;
341 
342 	msk = NULL;
343 	rc = -EINVAL;
344 
345 	/* We may be receiving a locally-routed packet; drop source sk
346 	 * accounting.
347 	 *
348 	 * From here, we will either queue the skb - either to a frag_queue, or
349 	 * to a receiving socket. When that succeeds, we clear the skb pointer;
350 	 * a non-NULL skb on exit will be otherwise unowned, and hence
351 	 * kfree_skb()-ed.
352 	 */
353 	skb_orphan(skb);
354 
355 	/* ensure we have enough data for a header and a type */
356 	if (skb->len < sizeof(struct mctp_hdr) + 1)
357 		goto out;
358 
359 	/* grab header, advance data ptr */
360 	mh = mctp_hdr(skb);
361 	skb_pull(skb, sizeof(struct mctp_hdr));
362 
363 	if (mh->ver != 1)
364 		goto out;
365 
366 	flags = mh->flags_seq_tag & (MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM);
367 	tag = mh->flags_seq_tag & (MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO);
368 
369 	rcu_read_lock();
370 
371 	/* lookup socket / reasm context, exactly matching (src,dest,tag).
372 	 * we hold a ref on the key, and key->lock held.
373 	 */
374 	key = mctp_lookup_key(net, skb, mh->src, &f);
375 
376 	if (flags & MCTP_HDR_FLAG_SOM) {
377 		if (key) {
378 			msk = container_of(key->sk, struct mctp_sock, sk);
379 		} else {
380 			/* first response to a broadcast? do a more general
381 			 * key lookup to find the socket, but don't use this
382 			 * key for reassembly - we'll create a more specific
383 			 * one for future packets if required (ie, !EOM).
384 			 */
385 			any_key = mctp_lookup_key(net, skb, MCTP_ADDR_ANY, &f);
386 			if (any_key) {
387 				msk = container_of(any_key->sk,
388 						   struct mctp_sock, sk);
389 				spin_unlock_irqrestore(&any_key->lock, f);
390 			}
391 		}
392 
393 		if (!key && !msk && (tag & MCTP_HDR_FLAG_TO))
394 			msk = mctp_lookup_bind(net, skb);
395 
396 		if (!msk) {
397 			rc = -ENOENT;
398 			goto out_unlock;
399 		}
400 
401 		/* single-packet message? deliver to socket, clean up any
402 		 * pending key.
403 		 */
404 		if (flags & MCTP_HDR_FLAG_EOM) {
405 			rc = sock_queue_rcv_skb(&msk->sk, skb);
406 			if (!rc)
407 				skb = NULL;
408 			if (key) {
409 				/* we've hit a pending reassembly; not much we
410 				 * can do but drop it
411 				 */
412 				__mctp_key_done_in(key, net, f,
413 						   MCTP_TRACE_KEY_REPLIED);
414 				key = NULL;
415 			}
416 			goto out_unlock;
417 		}
418 
419 		/* broadcast response or a bind() - create a key for further
420 		 * packets for this message
421 		 */
422 		if (!key) {
423 			key = mctp_key_alloc(msk, mh->dest, mh->src,
424 					     tag, GFP_ATOMIC);
425 			if (!key) {
426 				rc = -ENOMEM;
427 				goto out_unlock;
428 			}
429 
430 			/* we can queue without the key lock here, as the
431 			 * key isn't observable yet
432 			 */
433 			mctp_frag_queue(key, skb);
434 
435 			/* if the key_add fails, we've raced with another
436 			 * SOM packet with the same src, dest and tag. There's
437 			 * no way to distinguish future packets, so all we
438 			 * can do is drop; we'll free the skb on exit from
439 			 * this function.
440 			 */
441 			rc = mctp_key_add(key, msk);
442 			if (!rc) {
443 				trace_mctp_key_acquire(key);
444 				skb = NULL;
445 			}
446 
447 			/* we don't need to release key->lock on exit, so
448 			 * clean up here and suppress the unlock via
449 			 * setting to NULL
450 			 */
451 			mctp_key_unref(key);
452 			key = NULL;
453 
454 		} else {
455 			if (key->reasm_head || key->reasm_dead) {
456 				/* duplicate start? drop everything */
457 				__mctp_key_done_in(key, net, f,
458 						   MCTP_TRACE_KEY_INVALIDATED);
459 				rc = -EEXIST;
460 				key = NULL;
461 			} else {
462 				rc = mctp_frag_queue(key, skb);
463 				if (!rc)
464 					skb = NULL;
465 			}
466 		}
467 
468 	} else if (key) {
469 		/* this packet continues a previous message; reassemble
470 		 * using the message-specific key
471 		 */
472 
473 		/* we need to be continuing an existing reassembly... */
474 		if (!key->reasm_head)
475 			rc = -EINVAL;
476 		else
477 			rc = mctp_frag_queue(key, skb);
478 
479 		if (rc)
480 			goto out_unlock;
481 
482 		/* we've queued; the queue owns the skb now */
483 		skb = NULL;
484 
485 		/* end of message? deliver to socket, and we're done with
486 		 * the reassembly/response key
487 		 */
488 		if (flags & MCTP_HDR_FLAG_EOM) {
489 			rc = sock_queue_rcv_skb(key->sk, key->reasm_head);
490 			if (!rc)
491 				key->reasm_head = NULL;
492 			__mctp_key_done_in(key, net, f, MCTP_TRACE_KEY_REPLIED);
493 			key = NULL;
494 		}
495 
496 	} else {
497 		/* not a start, no matching key */
498 		rc = -ENOENT;
499 	}
500 
501 out_unlock:
502 	rcu_read_unlock();
503 	if (key) {
504 		spin_unlock_irqrestore(&key->lock, f);
505 		mctp_key_unref(key);
506 	}
507 	if (any_key)
508 		mctp_key_unref(any_key);
509 out:
510 	kfree_skb(skb);
511 	return rc;
512 }
513 
mctp_route_mtu(struct mctp_route * rt)514 static unsigned int mctp_route_mtu(struct mctp_route *rt)
515 {
516 	return rt->mtu ?: READ_ONCE(rt->dev->dev->mtu);
517 }
518 
mctp_route_output(struct mctp_route * route,struct sk_buff * skb)519 static int mctp_route_output(struct mctp_route *route, struct sk_buff *skb)
520 {
521 	struct mctp_skb_cb *cb = mctp_cb(skb);
522 	struct mctp_hdr *hdr = mctp_hdr(skb);
523 	char daddr_buf[MAX_ADDR_LEN];
524 	char *daddr = NULL;
525 	unsigned int mtu;
526 	int rc;
527 
528 	skb->protocol = htons(ETH_P_MCTP);
529 
530 	mtu = READ_ONCE(skb->dev->mtu);
531 	if (skb->len > mtu) {
532 		kfree_skb(skb);
533 		return -EMSGSIZE;
534 	}
535 
536 	if (cb->ifindex) {
537 		/* direct route; use the hwaddr we stashed in sendmsg */
538 		if (cb->halen != skb->dev->addr_len) {
539 			/* sanity check, sendmsg should have already caught this */
540 			kfree_skb(skb);
541 			return -EMSGSIZE;
542 		}
543 		daddr = cb->haddr;
544 	} else {
545 		/* If lookup fails let the device handle daddr==NULL */
546 		if (mctp_neigh_lookup(route->dev, hdr->dest, daddr_buf) == 0)
547 			daddr = daddr_buf;
548 	}
549 
550 	rc = dev_hard_header(skb, skb->dev, ntohs(skb->protocol),
551 			     daddr, skb->dev->dev_addr, skb->len);
552 	if (rc < 0) {
553 		kfree_skb(skb);
554 		return -EHOSTUNREACH;
555 	}
556 
557 	mctp_flow_prepare_output(skb, route->dev);
558 
559 	rc = dev_queue_xmit(skb);
560 	if (rc)
561 		rc = net_xmit_errno(rc);
562 
563 	return rc;
564 }
565 
566 /* route alloc/release */
mctp_route_release(struct mctp_route * rt)567 static void mctp_route_release(struct mctp_route *rt)
568 {
569 	if (refcount_dec_and_test(&rt->refs)) {
570 		mctp_dev_put(rt->dev);
571 		kfree_rcu(rt, rcu);
572 	}
573 }
574 
575 /* returns a route with the refcount at 1 */
mctp_route_alloc(void)576 static struct mctp_route *mctp_route_alloc(void)
577 {
578 	struct mctp_route *rt;
579 
580 	rt = kzalloc(sizeof(*rt), GFP_KERNEL);
581 	if (!rt)
582 		return NULL;
583 
584 	INIT_LIST_HEAD(&rt->list);
585 	refcount_set(&rt->refs, 1);
586 	rt->output = mctp_route_discard;
587 
588 	return rt;
589 }
590 
mctp_default_net(struct net * net)591 unsigned int mctp_default_net(struct net *net)
592 {
593 	return READ_ONCE(net->mctp.default_net);
594 }
595 
mctp_default_net_set(struct net * net,unsigned int index)596 int mctp_default_net_set(struct net *net, unsigned int index)
597 {
598 	if (index == 0)
599 		return -EINVAL;
600 	WRITE_ONCE(net->mctp.default_net, index);
601 	return 0;
602 }
603 
604 /* tag management */
mctp_reserve_tag(struct net * net,struct mctp_sk_key * key,struct mctp_sock * msk)605 static void mctp_reserve_tag(struct net *net, struct mctp_sk_key *key,
606 			     struct mctp_sock *msk)
607 {
608 	struct netns_mctp *mns = &net->mctp;
609 
610 	lockdep_assert_held(&mns->keys_lock);
611 
612 	key->expiry = jiffies + mctp_key_lifetime;
613 	timer_reduce(&msk->key_expiry, key->expiry);
614 
615 	/* we hold the net->key_lock here, allowing updates to both
616 	 * then net and sk
617 	 */
618 	hlist_add_head_rcu(&key->hlist, &mns->keys);
619 	hlist_add_head_rcu(&key->sklist, &msk->keys);
620 	refcount_inc(&key->refs);
621 }
622 
623 /* Allocate a locally-owned tag value for (saddr, daddr), and reserve
624  * it for the socket msk
625  */
mctp_alloc_local_tag(struct mctp_sock * msk,mctp_eid_t daddr,mctp_eid_t saddr,bool manual,u8 * tagp)626 struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk,
627 					 mctp_eid_t daddr, mctp_eid_t saddr,
628 					 bool manual, u8 *tagp)
629 {
630 	struct net *net = sock_net(&msk->sk);
631 	struct netns_mctp *mns = &net->mctp;
632 	struct mctp_sk_key *key, *tmp;
633 	unsigned long flags;
634 	u8 tagbits;
635 
636 	/* for NULL destination EIDs, we may get a response from any peer */
637 	if (daddr == MCTP_ADDR_NULL)
638 		daddr = MCTP_ADDR_ANY;
639 
640 	/* be optimistic, alloc now */
641 	key = mctp_key_alloc(msk, saddr, daddr, 0, GFP_KERNEL);
642 	if (!key)
643 		return ERR_PTR(-ENOMEM);
644 
645 	/* 8 possible tag values */
646 	tagbits = 0xff;
647 
648 	spin_lock_irqsave(&mns->keys_lock, flags);
649 
650 	/* Walk through the existing keys, looking for potential conflicting
651 	 * tags. If we find a conflict, clear that bit from tagbits
652 	 */
653 	hlist_for_each_entry(tmp, &mns->keys, hlist) {
654 		/* We can check the lookup fields (*_addr, tag) without the
655 		 * lock held, they don't change over the lifetime of the key.
656 		 */
657 
658 		/* if we don't own the tag, it can't conflict */
659 		if (tmp->tag & MCTP_HDR_FLAG_TO)
660 			continue;
661 
662 		if (!(mctp_address_matches(tmp->peer_addr, daddr) &&
663 		      mctp_address_matches(tmp->local_addr, saddr)))
664 			continue;
665 
666 		spin_lock(&tmp->lock);
667 		/* key must still be valid. If we find a match, clear the
668 		 * potential tag value
669 		 */
670 		if (tmp->valid)
671 			tagbits &= ~(1 << tmp->tag);
672 		spin_unlock(&tmp->lock);
673 
674 		if (!tagbits)
675 			break;
676 	}
677 
678 	if (tagbits) {
679 		key->tag = __ffs(tagbits);
680 		mctp_reserve_tag(net, key, msk);
681 		trace_mctp_key_acquire(key);
682 
683 		key->manual_alloc = manual;
684 		*tagp = key->tag;
685 	}
686 
687 	spin_unlock_irqrestore(&mns->keys_lock, flags);
688 
689 	if (!tagbits) {
690 		mctp_key_unref(key);
691 		return ERR_PTR(-EBUSY);
692 	}
693 
694 	return key;
695 }
696 
mctp_lookup_prealloc_tag(struct mctp_sock * msk,mctp_eid_t daddr,u8 req_tag,u8 * tagp)697 static struct mctp_sk_key *mctp_lookup_prealloc_tag(struct mctp_sock *msk,
698 						    mctp_eid_t daddr,
699 						    u8 req_tag, u8 *tagp)
700 {
701 	struct net *net = sock_net(&msk->sk);
702 	struct netns_mctp *mns = &net->mctp;
703 	struct mctp_sk_key *key, *tmp;
704 	unsigned long flags;
705 
706 	req_tag &= ~(MCTP_TAG_PREALLOC | MCTP_TAG_OWNER);
707 	key = NULL;
708 
709 	spin_lock_irqsave(&mns->keys_lock, flags);
710 
711 	hlist_for_each_entry(tmp, &mns->keys, hlist) {
712 		if (tmp->tag != req_tag)
713 			continue;
714 
715 		if (!mctp_address_matches(tmp->peer_addr, daddr))
716 			continue;
717 
718 		if (!tmp->manual_alloc)
719 			continue;
720 
721 		spin_lock(&tmp->lock);
722 		if (tmp->valid) {
723 			key = tmp;
724 			refcount_inc(&key->refs);
725 			spin_unlock(&tmp->lock);
726 			break;
727 		}
728 		spin_unlock(&tmp->lock);
729 	}
730 	spin_unlock_irqrestore(&mns->keys_lock, flags);
731 
732 	if (!key)
733 		return ERR_PTR(-ENOENT);
734 
735 	if (tagp)
736 		*tagp = key->tag;
737 
738 	return key;
739 }
740 
741 /* routing lookups */
mctp_rt_match_eid(struct mctp_route * rt,unsigned int net,mctp_eid_t eid)742 static bool mctp_rt_match_eid(struct mctp_route *rt,
743 			      unsigned int net, mctp_eid_t eid)
744 {
745 	return READ_ONCE(rt->dev->net) == net &&
746 		rt->min <= eid && rt->max >= eid;
747 }
748 
749 /* compares match, used for duplicate prevention */
mctp_rt_compare_exact(struct mctp_route * rt1,struct mctp_route * rt2)750 static bool mctp_rt_compare_exact(struct mctp_route *rt1,
751 				  struct mctp_route *rt2)
752 {
753 	ASSERT_RTNL();
754 	return rt1->dev->net == rt2->dev->net &&
755 		rt1->min == rt2->min &&
756 		rt1->max == rt2->max;
757 }
758 
mctp_route_lookup(struct net * net,unsigned int dnet,mctp_eid_t daddr)759 struct mctp_route *mctp_route_lookup(struct net *net, unsigned int dnet,
760 				     mctp_eid_t daddr)
761 {
762 	struct mctp_route *tmp, *rt = NULL;
763 
764 	rcu_read_lock();
765 
766 	list_for_each_entry_rcu(tmp, &net->mctp.routes, list) {
767 		/* TODO: add metrics */
768 		if (mctp_rt_match_eid(tmp, dnet, daddr)) {
769 			if (refcount_inc_not_zero(&tmp->refs)) {
770 				rt = tmp;
771 				break;
772 			}
773 		}
774 	}
775 
776 	rcu_read_unlock();
777 
778 	return rt;
779 }
780 
mctp_route_lookup_null(struct net * net,struct net_device * dev)781 static struct mctp_route *mctp_route_lookup_null(struct net *net,
782 						 struct net_device *dev)
783 {
784 	struct mctp_route *tmp, *rt = NULL;
785 
786 	rcu_read_lock();
787 
788 	list_for_each_entry_rcu(tmp, &net->mctp.routes, list) {
789 		if (tmp->dev->dev == dev && tmp->type == RTN_LOCAL &&
790 		    refcount_inc_not_zero(&tmp->refs)) {
791 			rt = tmp;
792 			break;
793 		}
794 	}
795 
796 	rcu_read_unlock();
797 
798 	return rt;
799 }
800 
mctp_do_fragment_route(struct mctp_route * rt,struct sk_buff * skb,unsigned int mtu,u8 tag)801 static int mctp_do_fragment_route(struct mctp_route *rt, struct sk_buff *skb,
802 				  unsigned int mtu, u8 tag)
803 {
804 	const unsigned int hlen = sizeof(struct mctp_hdr);
805 	struct mctp_hdr *hdr, *hdr2;
806 	unsigned int pos, size, headroom;
807 	struct sk_buff *skb2;
808 	int rc;
809 	u8 seq;
810 
811 	hdr = mctp_hdr(skb);
812 	seq = 0;
813 	rc = 0;
814 
815 	if (mtu < hlen + 1) {
816 		kfree_skb(skb);
817 		return -EMSGSIZE;
818 	}
819 
820 	/* keep same headroom as the original skb */
821 	headroom = skb_headroom(skb);
822 
823 	/* we've got the header */
824 	skb_pull(skb, hlen);
825 
826 	for (pos = 0; pos < skb->len;) {
827 		/* size of message payload */
828 		size = min(mtu - hlen, skb->len - pos);
829 
830 		skb2 = alloc_skb(headroom + hlen + size, GFP_KERNEL);
831 		if (!skb2) {
832 			rc = -ENOMEM;
833 			break;
834 		}
835 
836 		/* generic skb copy */
837 		skb2->protocol = skb->protocol;
838 		skb2->priority = skb->priority;
839 		skb2->dev = skb->dev;
840 		memcpy(skb2->cb, skb->cb, sizeof(skb2->cb));
841 
842 		if (skb->sk)
843 			skb_set_owner_w(skb2, skb->sk);
844 
845 		/* establish packet */
846 		skb_reserve(skb2, headroom);
847 		skb_reset_network_header(skb2);
848 		skb_put(skb2, hlen + size);
849 		skb2->transport_header = skb2->network_header + hlen;
850 
851 		/* copy header fields, calculate SOM/EOM flags & seq */
852 		hdr2 = mctp_hdr(skb2);
853 		hdr2->ver = hdr->ver;
854 		hdr2->dest = hdr->dest;
855 		hdr2->src = hdr->src;
856 		hdr2->flags_seq_tag = tag &
857 			(MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO);
858 
859 		if (pos == 0)
860 			hdr2->flags_seq_tag |= MCTP_HDR_FLAG_SOM;
861 
862 		if (pos + size == skb->len)
863 			hdr2->flags_seq_tag |= MCTP_HDR_FLAG_EOM;
864 
865 		hdr2->flags_seq_tag |= seq << MCTP_HDR_SEQ_SHIFT;
866 
867 		/* copy message payload */
868 		skb_copy_bits(skb, pos, skb_transport_header(skb2), size);
869 
870 		/* we need to copy the extensions, for MCTP flow data */
871 		skb_ext_copy(skb2, skb);
872 
873 		/* do route */
874 		rc = rt->output(rt, skb2);
875 		if (rc)
876 			break;
877 
878 		seq = (seq + 1) & MCTP_HDR_SEQ_MASK;
879 		pos += size;
880 	}
881 
882 	consume_skb(skb);
883 	return rc;
884 }
885 
mctp_local_output(struct sock * sk,struct mctp_route * rt,struct sk_buff * skb,mctp_eid_t daddr,u8 req_tag)886 int mctp_local_output(struct sock *sk, struct mctp_route *rt,
887 		      struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag)
888 {
889 	struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);
890 	struct mctp_skb_cb *cb = mctp_cb(skb);
891 	struct mctp_route tmp_rt = {0};
892 	struct mctp_sk_key *key;
893 	struct mctp_hdr *hdr;
894 	unsigned long flags;
895 	unsigned int mtu;
896 	mctp_eid_t saddr;
897 	bool ext_rt;
898 	int rc;
899 	u8 tag;
900 
901 	rc = -ENODEV;
902 
903 	if (rt) {
904 		ext_rt = false;
905 		if (WARN_ON(!rt->dev))
906 			goto out_release;
907 
908 	} else if (cb->ifindex) {
909 		struct net_device *dev;
910 
911 		ext_rt = true;
912 		rt = &tmp_rt;
913 
914 		rcu_read_lock();
915 		dev = dev_get_by_index_rcu(sock_net(sk), cb->ifindex);
916 		if (!dev) {
917 			rcu_read_unlock();
918 			goto out_free;
919 		}
920 		rt->dev = __mctp_dev_get(dev);
921 		rcu_read_unlock();
922 
923 		if (!rt->dev)
924 			goto out_release;
925 
926 		/* establish temporary route - we set up enough to keep
927 		 * mctp_route_output happy
928 		 */
929 		rt->output = mctp_route_output;
930 		rt->mtu = 0;
931 
932 	} else {
933 		rc = -EINVAL;
934 		goto out_free;
935 	}
936 
937 	spin_lock_irqsave(&rt->dev->addrs_lock, flags);
938 	if (rt->dev->num_addrs == 0) {
939 		rc = -EHOSTUNREACH;
940 	} else {
941 		/* use the outbound interface's first address as our source */
942 		saddr = rt->dev->addrs[0];
943 		rc = 0;
944 	}
945 	spin_unlock_irqrestore(&rt->dev->addrs_lock, flags);
946 
947 	if (rc)
948 		goto out_release;
949 
950 	if (req_tag & MCTP_TAG_OWNER) {
951 		if (req_tag & MCTP_TAG_PREALLOC)
952 			key = mctp_lookup_prealloc_tag(msk, daddr,
953 						       req_tag, &tag);
954 		else
955 			key = mctp_alloc_local_tag(msk, daddr, saddr,
956 						   false, &tag);
957 
958 		if (IS_ERR(key)) {
959 			rc = PTR_ERR(key);
960 			goto out_release;
961 		}
962 		mctp_skb_set_flow(skb, key);
963 		/* done with the key in this scope */
964 		mctp_key_unref(key);
965 		tag |= MCTP_HDR_FLAG_TO;
966 	} else {
967 		key = NULL;
968 		tag = req_tag & MCTP_TAG_MASK;
969 	}
970 
971 	skb->protocol = htons(ETH_P_MCTP);
972 	skb->priority = 0;
973 	skb_reset_transport_header(skb);
974 	skb_push(skb, sizeof(struct mctp_hdr));
975 	skb_reset_network_header(skb);
976 	skb->dev = rt->dev->dev;
977 
978 	/* cb->net will have been set on initial ingress */
979 	cb->src = saddr;
980 
981 	/* set up common header fields */
982 	hdr = mctp_hdr(skb);
983 	hdr->ver = 1;
984 	hdr->dest = daddr;
985 	hdr->src = saddr;
986 
987 	mtu = mctp_route_mtu(rt);
988 
989 	if (skb->len + sizeof(struct mctp_hdr) <= mtu) {
990 		hdr->flags_seq_tag = MCTP_HDR_FLAG_SOM |
991 			MCTP_HDR_FLAG_EOM | tag;
992 		rc = rt->output(rt, skb);
993 	} else {
994 		rc = mctp_do_fragment_route(rt, skb, mtu, tag);
995 	}
996 
997 	/* route output functions consume the skb, even on error */
998 	skb = NULL;
999 
1000 out_release:
1001 	if (!ext_rt)
1002 		mctp_route_release(rt);
1003 
1004 	mctp_dev_put(tmp_rt.dev);
1005 
1006 out_free:
1007 	kfree_skb(skb);
1008 	return rc;
1009 }
1010 
1011 /* route management */
mctp_route_add(struct mctp_dev * mdev,mctp_eid_t daddr_start,unsigned int daddr_extent,unsigned int mtu,unsigned char type)1012 static int mctp_route_add(struct mctp_dev *mdev, mctp_eid_t daddr_start,
1013 			  unsigned int daddr_extent, unsigned int mtu,
1014 			  unsigned char type)
1015 {
1016 	int (*rtfn)(struct mctp_route *rt, struct sk_buff *skb);
1017 	struct net *net = dev_net(mdev->dev);
1018 	struct mctp_route *rt, *ert;
1019 
1020 	if (!mctp_address_unicast(daddr_start))
1021 		return -EINVAL;
1022 
1023 	if (daddr_extent > 0xff || daddr_start + daddr_extent >= 255)
1024 		return -EINVAL;
1025 
1026 	switch (type) {
1027 	case RTN_LOCAL:
1028 		rtfn = mctp_route_input;
1029 		break;
1030 	case RTN_UNICAST:
1031 		rtfn = mctp_route_output;
1032 		break;
1033 	default:
1034 		return -EINVAL;
1035 	}
1036 
1037 	rt = mctp_route_alloc();
1038 	if (!rt)
1039 		return -ENOMEM;
1040 
1041 	rt->min = daddr_start;
1042 	rt->max = daddr_start + daddr_extent;
1043 	rt->mtu = mtu;
1044 	rt->dev = mdev;
1045 	mctp_dev_hold(rt->dev);
1046 	rt->type = type;
1047 	rt->output = rtfn;
1048 
1049 	ASSERT_RTNL();
1050 	/* Prevent duplicate identical routes. */
1051 	list_for_each_entry(ert, &net->mctp.routes, list) {
1052 		if (mctp_rt_compare_exact(rt, ert)) {
1053 			mctp_route_release(rt);
1054 			return -EEXIST;
1055 		}
1056 	}
1057 
1058 	list_add_rcu(&rt->list, &net->mctp.routes);
1059 
1060 	return 0;
1061 }
1062 
mctp_route_remove(struct mctp_dev * mdev,mctp_eid_t daddr_start,unsigned int daddr_extent,unsigned char type)1063 static int mctp_route_remove(struct mctp_dev *mdev, mctp_eid_t daddr_start,
1064 			     unsigned int daddr_extent, unsigned char type)
1065 {
1066 	struct net *net = dev_net(mdev->dev);
1067 	struct mctp_route *rt, *tmp;
1068 	mctp_eid_t daddr_end;
1069 	bool dropped;
1070 
1071 	if (daddr_extent > 0xff || daddr_start + daddr_extent >= 255)
1072 		return -EINVAL;
1073 
1074 	daddr_end = daddr_start + daddr_extent;
1075 	dropped = false;
1076 
1077 	ASSERT_RTNL();
1078 
1079 	list_for_each_entry_safe(rt, tmp, &net->mctp.routes, list) {
1080 		if (rt->dev == mdev &&
1081 		    rt->min == daddr_start && rt->max == daddr_end &&
1082 		    rt->type == type) {
1083 			list_del_rcu(&rt->list);
1084 			/* TODO: immediate RTM_DELROUTE */
1085 			mctp_route_release(rt);
1086 			dropped = true;
1087 		}
1088 	}
1089 
1090 	return dropped ? 0 : -ENOENT;
1091 }
1092 
mctp_route_add_local(struct mctp_dev * mdev,mctp_eid_t addr)1093 int mctp_route_add_local(struct mctp_dev *mdev, mctp_eid_t addr)
1094 {
1095 	return mctp_route_add(mdev, addr, 0, 0, RTN_LOCAL);
1096 }
1097 
mctp_route_remove_local(struct mctp_dev * mdev,mctp_eid_t addr)1098 int mctp_route_remove_local(struct mctp_dev *mdev, mctp_eid_t addr)
1099 {
1100 	return mctp_route_remove(mdev, addr, 0, RTN_LOCAL);
1101 }
1102 
1103 /* removes all entries for a given device */
mctp_route_remove_dev(struct mctp_dev * mdev)1104 void mctp_route_remove_dev(struct mctp_dev *mdev)
1105 {
1106 	struct net *net = dev_net(mdev->dev);
1107 	struct mctp_route *rt, *tmp;
1108 
1109 	ASSERT_RTNL();
1110 	list_for_each_entry_safe(rt, tmp, &net->mctp.routes, list) {
1111 		if (rt->dev == mdev) {
1112 			list_del_rcu(&rt->list);
1113 			/* TODO: immediate RTM_DELROUTE */
1114 			mctp_route_release(rt);
1115 		}
1116 	}
1117 }
1118 
1119 /* Incoming packet-handling */
1120 
mctp_pkttype_receive(struct sk_buff * skb,struct net_device * dev,struct packet_type * pt,struct net_device * orig_dev)1121 static int mctp_pkttype_receive(struct sk_buff *skb, struct net_device *dev,
1122 				struct packet_type *pt,
1123 				struct net_device *orig_dev)
1124 {
1125 	struct net *net = dev_net(dev);
1126 	struct mctp_dev *mdev;
1127 	struct mctp_skb_cb *cb;
1128 	struct mctp_route *rt;
1129 	struct mctp_hdr *mh;
1130 
1131 	rcu_read_lock();
1132 	mdev = __mctp_dev_get(dev);
1133 	rcu_read_unlock();
1134 	if (!mdev) {
1135 		/* basic non-data sanity checks */
1136 		goto err_drop;
1137 	}
1138 
1139 	if (!pskb_may_pull(skb, sizeof(struct mctp_hdr)))
1140 		goto err_drop;
1141 
1142 	skb_reset_transport_header(skb);
1143 	skb_reset_network_header(skb);
1144 
1145 	/* We have enough for a header; decode and route */
1146 	mh = mctp_hdr(skb);
1147 	if (mh->ver < MCTP_VER_MIN || mh->ver > MCTP_VER_MAX)
1148 		goto err_drop;
1149 
1150 	/* source must be valid unicast or null; drop reserved ranges and
1151 	 * broadcast
1152 	 */
1153 	if (!(mctp_address_unicast(mh->src) || mctp_address_null(mh->src)))
1154 		goto err_drop;
1155 
1156 	/* dest address: as above, but allow broadcast */
1157 	if (!(mctp_address_unicast(mh->dest) || mctp_address_null(mh->dest) ||
1158 	      mctp_address_broadcast(mh->dest)))
1159 		goto err_drop;
1160 
1161 	/* MCTP drivers must populate halen/haddr */
1162 	if (dev->type == ARPHRD_MCTP) {
1163 		cb = mctp_cb(skb);
1164 	} else {
1165 		cb = __mctp_cb(skb);
1166 		cb->halen = 0;
1167 	}
1168 	cb->net = READ_ONCE(mdev->net);
1169 	cb->ifindex = dev->ifindex;
1170 
1171 	rt = mctp_route_lookup(net, cb->net, mh->dest);
1172 
1173 	/* NULL EID, but addressed to our physical address */
1174 	if (!rt && mh->dest == MCTP_ADDR_NULL && skb->pkt_type == PACKET_HOST)
1175 		rt = mctp_route_lookup_null(net, dev);
1176 
1177 	if (!rt)
1178 		goto err_drop;
1179 
1180 	rt->output(rt, skb);
1181 	mctp_route_release(rt);
1182 	mctp_dev_put(mdev);
1183 
1184 	return NET_RX_SUCCESS;
1185 
1186 err_drop:
1187 	kfree_skb(skb);
1188 	mctp_dev_put(mdev);
1189 	return NET_RX_DROP;
1190 }
1191 
1192 static struct packet_type mctp_packet_type = {
1193 	.type = cpu_to_be16(ETH_P_MCTP),
1194 	.func = mctp_pkttype_receive,
1195 };
1196 
1197 /* netlink interface */
1198 
1199 static const struct nla_policy rta_mctp_policy[RTA_MAX + 1] = {
1200 	[RTA_DST]		= { .type = NLA_U8 },
1201 	[RTA_METRICS]		= { .type = NLA_NESTED },
1202 	[RTA_OIF]		= { .type = NLA_U32 },
1203 };
1204 
1205 /* Common part for RTM_NEWROUTE and RTM_DELROUTE parsing.
1206  * tb must hold RTA_MAX+1 elements.
1207  */
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)1208 static int mctp_route_nlparse(struct sk_buff *skb, struct nlmsghdr *nlh,
1209 			      struct netlink_ext_ack *extack,
1210 			      struct nlattr **tb, struct rtmsg **rtm,
1211 			      struct mctp_dev **mdev, mctp_eid_t *daddr_start)
1212 {
1213 	struct net *net = sock_net(skb->sk);
1214 	struct net_device *dev;
1215 	unsigned int ifindex;
1216 	int rc;
1217 
1218 	rc = nlmsg_parse(nlh, sizeof(struct rtmsg), tb, RTA_MAX,
1219 			 rta_mctp_policy, extack);
1220 	if (rc < 0) {
1221 		NL_SET_ERR_MSG(extack, "incorrect format");
1222 		return rc;
1223 	}
1224 
1225 	if (!tb[RTA_DST]) {
1226 		NL_SET_ERR_MSG(extack, "dst EID missing");
1227 		return -EINVAL;
1228 	}
1229 	*daddr_start = nla_get_u8(tb[RTA_DST]);
1230 
1231 	if (!tb[RTA_OIF]) {
1232 		NL_SET_ERR_MSG(extack, "ifindex missing");
1233 		return -EINVAL;
1234 	}
1235 	ifindex = nla_get_u32(tb[RTA_OIF]);
1236 
1237 	*rtm = nlmsg_data(nlh);
1238 	if ((*rtm)->rtm_family != AF_MCTP) {
1239 		NL_SET_ERR_MSG(extack, "route family must be AF_MCTP");
1240 		return -EINVAL;
1241 	}
1242 
1243 	dev = __dev_get_by_index(net, ifindex);
1244 	if (!dev) {
1245 		NL_SET_ERR_MSG(extack, "bad ifindex");
1246 		return -ENODEV;
1247 	}
1248 	*mdev = mctp_dev_get_rtnl(dev);
1249 	if (!*mdev)
1250 		return -ENODEV;
1251 
1252 	if (dev->flags & IFF_LOOPBACK) {
1253 		NL_SET_ERR_MSG(extack, "no routes to loopback");
1254 		return -EINVAL;
1255 	}
1256 
1257 	return 0;
1258 }
1259 
1260 static const struct nla_policy rta_metrics_policy[RTAX_MAX + 1] = {
1261 	[RTAX_MTU]		= { .type = NLA_U32 },
1262 };
1263 
mctp_newroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)1264 static int mctp_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
1265 			 struct netlink_ext_ack *extack)
1266 {
1267 	struct nlattr *tb[RTA_MAX + 1];
1268 	struct nlattr *tbx[RTAX_MAX + 1];
1269 	mctp_eid_t daddr_start;
1270 	struct mctp_dev *mdev;
1271 	struct rtmsg *rtm;
1272 	unsigned int mtu;
1273 	int rc;
1274 
1275 	rc = mctp_route_nlparse(skb, nlh, extack, tb,
1276 				&rtm, &mdev, &daddr_start);
1277 	if (rc < 0)
1278 		return rc;
1279 
1280 	if (rtm->rtm_type != RTN_UNICAST) {
1281 		NL_SET_ERR_MSG(extack, "rtm_type must be RTN_UNICAST");
1282 		return -EINVAL;
1283 	}
1284 
1285 	mtu = 0;
1286 	if (tb[RTA_METRICS]) {
1287 		rc = nla_parse_nested(tbx, RTAX_MAX, tb[RTA_METRICS],
1288 				      rta_metrics_policy, NULL);
1289 		if (rc < 0)
1290 			return rc;
1291 		if (tbx[RTAX_MTU])
1292 			mtu = nla_get_u32(tbx[RTAX_MTU]);
1293 	}
1294 
1295 	rc = mctp_route_add(mdev, daddr_start, rtm->rtm_dst_len, mtu,
1296 			    rtm->rtm_type);
1297 	return rc;
1298 }
1299 
mctp_delroute(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)1300 static int mctp_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
1301 			 struct netlink_ext_ack *extack)
1302 {
1303 	struct nlattr *tb[RTA_MAX + 1];
1304 	mctp_eid_t daddr_start;
1305 	struct mctp_dev *mdev;
1306 	struct rtmsg *rtm;
1307 	int rc;
1308 
1309 	rc = mctp_route_nlparse(skb, nlh, extack, tb,
1310 				&rtm, &mdev, &daddr_start);
1311 	if (rc < 0)
1312 		return rc;
1313 
1314 	/* we only have unicast routes */
1315 	if (rtm->rtm_type != RTN_UNICAST)
1316 		return -EINVAL;
1317 
1318 	rc = mctp_route_remove(mdev, daddr_start, rtm->rtm_dst_len, RTN_UNICAST);
1319 	return rc;
1320 }
1321 
mctp_fill_rtinfo(struct sk_buff * skb,struct mctp_route * rt,u32 portid,u32 seq,int event,unsigned int flags)1322 static int mctp_fill_rtinfo(struct sk_buff *skb, struct mctp_route *rt,
1323 			    u32 portid, u32 seq, int event, unsigned int flags)
1324 {
1325 	struct nlmsghdr *nlh;
1326 	struct rtmsg *hdr;
1327 	void *metrics;
1328 
1329 	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*hdr), flags);
1330 	if (!nlh)
1331 		return -EMSGSIZE;
1332 
1333 	hdr = nlmsg_data(nlh);
1334 	hdr->rtm_family = AF_MCTP;
1335 
1336 	/* we use the _len fields as a number of EIDs, rather than
1337 	 * a number of bits in the address
1338 	 */
1339 	hdr->rtm_dst_len = rt->max - rt->min;
1340 	hdr->rtm_src_len = 0;
1341 	hdr->rtm_tos = 0;
1342 	hdr->rtm_table = RT_TABLE_DEFAULT;
1343 	hdr->rtm_protocol = RTPROT_STATIC; /* everything is user-defined */
1344 	hdr->rtm_scope = RT_SCOPE_LINK; /* TODO: scope in mctp_route? */
1345 	hdr->rtm_type = rt->type;
1346 
1347 	if (nla_put_u8(skb, RTA_DST, rt->min))
1348 		goto cancel;
1349 
1350 	metrics = nla_nest_start_noflag(skb, RTA_METRICS);
1351 	if (!metrics)
1352 		goto cancel;
1353 
1354 	if (rt->mtu) {
1355 		if (nla_put_u32(skb, RTAX_MTU, rt->mtu))
1356 			goto cancel;
1357 	}
1358 
1359 	nla_nest_end(skb, metrics);
1360 
1361 	if (rt->dev) {
1362 		if (nla_put_u32(skb, RTA_OIF, rt->dev->dev->ifindex))
1363 			goto cancel;
1364 	}
1365 
1366 	/* TODO: conditional neighbour physaddr? */
1367 
1368 	nlmsg_end(skb, nlh);
1369 
1370 	return 0;
1371 
1372 cancel:
1373 	nlmsg_cancel(skb, nlh);
1374 	return -EMSGSIZE;
1375 }
1376 
mctp_dump_rtinfo(struct sk_buff * skb,struct netlink_callback * cb)1377 static int mctp_dump_rtinfo(struct sk_buff *skb, struct netlink_callback *cb)
1378 {
1379 	struct net *net = sock_net(skb->sk);
1380 	struct mctp_route *rt;
1381 	int s_idx, idx;
1382 
1383 	/* TODO: allow filtering on route data, possibly under
1384 	 * cb->strict_check
1385 	 */
1386 
1387 	/* TODO: change to struct overlay */
1388 	s_idx = cb->args[0];
1389 	idx = 0;
1390 
1391 	rcu_read_lock();
1392 	list_for_each_entry_rcu(rt, &net->mctp.routes, list) {
1393 		if (idx++ < s_idx)
1394 			continue;
1395 		if (mctp_fill_rtinfo(skb, rt,
1396 				     NETLINK_CB(cb->skb).portid,
1397 				     cb->nlh->nlmsg_seq,
1398 				     RTM_NEWROUTE, NLM_F_MULTI) < 0)
1399 			break;
1400 	}
1401 
1402 	rcu_read_unlock();
1403 	cb->args[0] = idx;
1404 
1405 	return skb->len;
1406 }
1407 
1408 /* net namespace implementation */
mctp_routes_net_init(struct net * net)1409 static int __net_init mctp_routes_net_init(struct net *net)
1410 {
1411 	struct netns_mctp *ns = &net->mctp;
1412 
1413 	INIT_LIST_HEAD(&ns->routes);
1414 	INIT_HLIST_HEAD(&ns->binds);
1415 	mutex_init(&ns->bind_lock);
1416 	INIT_HLIST_HEAD(&ns->keys);
1417 	spin_lock_init(&ns->keys_lock);
1418 	WARN_ON(mctp_default_net_set(net, MCTP_INITIAL_DEFAULT_NET));
1419 	return 0;
1420 }
1421 
mctp_routes_net_exit(struct net * net)1422 static void __net_exit mctp_routes_net_exit(struct net *net)
1423 {
1424 	struct mctp_route *rt;
1425 
1426 	rcu_read_lock();
1427 	list_for_each_entry_rcu(rt, &net->mctp.routes, list)
1428 		mctp_route_release(rt);
1429 	rcu_read_unlock();
1430 }
1431 
1432 static struct pernet_operations mctp_net_ops = {
1433 	.init = mctp_routes_net_init,
1434 	.exit = mctp_routes_net_exit,
1435 };
1436 
1437 static const struct rtnl_msg_handler mctp_route_rtnl_msg_handlers[] = {
1438 	{THIS_MODULE, PF_MCTP, RTM_NEWROUTE, mctp_newroute, NULL, 0},
1439 	{THIS_MODULE, PF_MCTP, RTM_DELROUTE, mctp_delroute, NULL, 0},
1440 	{THIS_MODULE, PF_MCTP, RTM_GETROUTE, NULL, mctp_dump_rtinfo, 0},
1441 };
1442 
mctp_routes_init(void)1443 int __init mctp_routes_init(void)
1444 {
1445 	int err;
1446 
1447 	dev_add_pack(&mctp_packet_type);
1448 
1449 	err = register_pernet_subsys(&mctp_net_ops);
1450 	if (err)
1451 		goto err_pernet;
1452 
1453 	err = rtnl_register_many(mctp_route_rtnl_msg_handlers);
1454 	if (err)
1455 		goto err_rtnl;
1456 
1457 	return 0;
1458 
1459 err_rtnl:
1460 	unregister_pernet_subsys(&mctp_net_ops);
1461 err_pernet:
1462 	dev_remove_pack(&mctp_packet_type);
1463 	return err;
1464 }
1465 
mctp_routes_exit(void)1466 void mctp_routes_exit(void)
1467 {
1468 	rtnl_unregister_many(mctp_route_rtnl_msg_handlers);
1469 	unregister_pernet_subsys(&mctp_net_ops);
1470 	dev_remove_pack(&mctp_packet_type);
1471 }
1472 
1473 #if IS_ENABLED(CONFIG_MCTP_TEST)
1474 #include "test/route-test.c"
1475 #endif
1476