xref: /openbmc/linux/net/rxrpc/peer_object.c (revision 8a758d98)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* RxRPC remote transport endpoint record management
3  *
4  * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
5  * Written by David Howells (dhowells@redhat.com)
6  */
7 
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9 
10 #include <linux/module.h>
11 #include <linux/net.h>
12 #include <linux/skbuff.h>
13 #include <linux/udp.h>
14 #include <linux/in.h>
15 #include <linux/in6.h>
16 #include <linux/slab.h>
17 #include <linux/hashtable.h>
18 #include <net/sock.h>
19 #include <net/af_rxrpc.h>
20 #include <net/ip.h>
21 #include <net/route.h>
22 #include <net/ip6_route.h>
23 #include "ar-internal.h"
24 
25 /*
26  * Hash a peer key.
27  */
rxrpc_peer_hash_key(struct rxrpc_local * local,const struct sockaddr_rxrpc * srx)28 static unsigned long rxrpc_peer_hash_key(struct rxrpc_local *local,
29 					 const struct sockaddr_rxrpc *srx)
30 {
31 	const u16 *p;
32 	unsigned int i, size;
33 	unsigned long hash_key;
34 
35 	_enter("");
36 
37 	hash_key = (unsigned long)local / __alignof__(*local);
38 	hash_key += srx->transport_type;
39 	hash_key += srx->transport_len;
40 	hash_key += srx->transport.family;
41 
42 	switch (srx->transport.family) {
43 	case AF_INET:
44 		hash_key += (u16 __force)srx->transport.sin.sin_port;
45 		size = sizeof(srx->transport.sin.sin_addr);
46 		p = (u16 *)&srx->transport.sin.sin_addr;
47 		break;
48 #ifdef CONFIG_AF_RXRPC_IPV6
49 	case AF_INET6:
50 		hash_key += (u16 __force)srx->transport.sin.sin_port;
51 		size = sizeof(srx->transport.sin6.sin6_addr);
52 		p = (u16 *)&srx->transport.sin6.sin6_addr;
53 		break;
54 #endif
55 	default:
56 		WARN(1, "AF_RXRPC: Unsupported transport address family\n");
57 		return 0;
58 	}
59 
60 	/* Step through the peer address in 16-bit portions for speed */
61 	for (i = 0; i < size; i += sizeof(*p), p++)
62 		hash_key += *p;
63 
64 	_leave(" 0x%lx", hash_key);
65 	return hash_key;
66 }
67 
68 /*
69  * Compare a peer to a key.  Return -ve, 0 or +ve to indicate less than, same
70  * or greater than.
71  *
72  * Unfortunately, the primitives in linux/hashtable.h don't allow for sorted
73  * buckets and mid-bucket insertion, so we don't make full use of this
74  * information at this point.
75  */
rxrpc_peer_cmp_key(const struct rxrpc_peer * peer,struct rxrpc_local * local,const struct sockaddr_rxrpc * srx,unsigned long hash_key)76 static long rxrpc_peer_cmp_key(const struct rxrpc_peer *peer,
77 			       struct rxrpc_local *local,
78 			       const struct sockaddr_rxrpc *srx,
79 			       unsigned long hash_key)
80 {
81 	long diff;
82 
83 	diff = ((peer->hash_key - hash_key) ?:
84 		((unsigned long)peer->local - (unsigned long)local) ?:
85 		(peer->srx.transport_type - srx->transport_type) ?:
86 		(peer->srx.transport_len - srx->transport_len) ?:
87 		(peer->srx.transport.family - srx->transport.family));
88 	if (diff != 0)
89 		return diff;
90 
91 	switch (srx->transport.family) {
92 	case AF_INET:
93 		return ((u16 __force)peer->srx.transport.sin.sin_port -
94 			(u16 __force)srx->transport.sin.sin_port) ?:
95 			memcmp(&peer->srx.transport.sin.sin_addr,
96 			       &srx->transport.sin.sin_addr,
97 			       sizeof(struct in_addr));
98 #ifdef CONFIG_AF_RXRPC_IPV6
99 	case AF_INET6:
100 		return ((u16 __force)peer->srx.transport.sin6.sin6_port -
101 			(u16 __force)srx->transport.sin6.sin6_port) ?:
102 			memcmp(&peer->srx.transport.sin6.sin6_addr,
103 			       &srx->transport.sin6.sin6_addr,
104 			       sizeof(struct in6_addr));
105 #endif
106 	default:
107 		BUG();
108 	}
109 }
110 
111 /*
112  * Look up a remote transport endpoint for the specified address using RCU.
113  */
__rxrpc_lookup_peer_rcu(struct rxrpc_local * local,const struct sockaddr_rxrpc * srx,unsigned long hash_key)114 static struct rxrpc_peer *__rxrpc_lookup_peer_rcu(
115 	struct rxrpc_local *local,
116 	const struct sockaddr_rxrpc *srx,
117 	unsigned long hash_key)
118 {
119 	struct rxrpc_peer *peer;
120 	struct rxrpc_net *rxnet = local->rxnet;
121 
122 	hash_for_each_possible_rcu(rxnet->peer_hash, peer, hash_link, hash_key) {
123 		if (rxrpc_peer_cmp_key(peer, local, srx, hash_key) == 0 &&
124 		    refcount_read(&peer->ref) > 0)
125 			return peer;
126 	}
127 
128 	return NULL;
129 }
130 
131 /*
132  * Look up a remote transport endpoint for the specified address using RCU.
133  */
rxrpc_lookup_peer_rcu(struct rxrpc_local * local,const struct sockaddr_rxrpc * srx)134 struct rxrpc_peer *rxrpc_lookup_peer_rcu(struct rxrpc_local *local,
135 					 const struct sockaddr_rxrpc *srx)
136 {
137 	struct rxrpc_peer *peer;
138 	unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
139 
140 	peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
141 	if (peer)
142 		_leave(" = %p {u=%d}", peer, refcount_read(&peer->ref));
143 	return peer;
144 }
145 
146 /*
147  * assess the MTU size for the network interface through which this peer is
148  * reached
149  */
rxrpc_assess_MTU_size(struct rxrpc_local * local,struct rxrpc_peer * peer)150 static void rxrpc_assess_MTU_size(struct rxrpc_local *local,
151 				  struct rxrpc_peer *peer)
152 {
153 	struct net *net = local->net;
154 	struct dst_entry *dst;
155 	struct rtable *rt;
156 	struct flowi fl;
157 	struct flowi4 *fl4 = &fl.u.ip4;
158 #ifdef CONFIG_AF_RXRPC_IPV6
159 	struct flowi6 *fl6 = &fl.u.ip6;
160 #endif
161 
162 	peer->if_mtu = 1500;
163 
164 	memset(&fl, 0, sizeof(fl));
165 	switch (peer->srx.transport.family) {
166 	case AF_INET:
167 		rt = ip_route_output_ports(
168 			net, fl4, NULL,
169 			peer->srx.transport.sin.sin_addr.s_addr, 0,
170 			htons(7000), htons(7001), IPPROTO_UDP, 0, 0);
171 		if (IS_ERR(rt)) {
172 			_leave(" [route err %ld]", PTR_ERR(rt));
173 			return;
174 		}
175 		dst = &rt->dst;
176 		break;
177 
178 #ifdef CONFIG_AF_RXRPC_IPV6
179 	case AF_INET6:
180 		fl6->flowi6_iif = LOOPBACK_IFINDEX;
181 		fl6->flowi6_scope = RT_SCOPE_UNIVERSE;
182 		fl6->flowi6_proto = IPPROTO_UDP;
183 		memcpy(&fl6->daddr, &peer->srx.transport.sin6.sin6_addr,
184 		       sizeof(struct in6_addr));
185 		fl6->fl6_dport = htons(7001);
186 		fl6->fl6_sport = htons(7000);
187 		dst = ip6_route_output(net, NULL, fl6);
188 		if (dst->error) {
189 			_leave(" [route err %d]", dst->error);
190 			return;
191 		}
192 		break;
193 #endif
194 
195 	default:
196 		BUG();
197 	}
198 
199 	peer->if_mtu = dst_mtu(dst);
200 	dst_release(dst);
201 
202 	_leave(" [if_mtu %u]", peer->if_mtu);
203 }
204 
205 /*
206  * Allocate a peer.
207  */
rxrpc_alloc_peer(struct rxrpc_local * local,gfp_t gfp,enum rxrpc_peer_trace why)208 struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp,
209 				    enum rxrpc_peer_trace why)
210 {
211 	struct rxrpc_peer *peer;
212 
213 	_enter("");
214 
215 	peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
216 	if (peer) {
217 		refcount_set(&peer->ref, 1);
218 		peer->local = rxrpc_get_local(local, rxrpc_local_get_peer);
219 		INIT_HLIST_HEAD(&peer->error_targets);
220 		peer->service_conns = RB_ROOT;
221 		seqlock_init(&peer->service_conn_lock);
222 		spin_lock_init(&peer->lock);
223 		spin_lock_init(&peer->rtt_input_lock);
224 		peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
225 
226 		rxrpc_peer_init_rtt(peer);
227 
228 		peer->cong_ssthresh = RXRPC_TX_MAX_WINDOW;
229 		trace_rxrpc_peer(peer->debug_id, 1, why);
230 	}
231 
232 	_leave(" = %p", peer);
233 	return peer;
234 }
235 
236 /*
237  * Initialise peer record.
238  */
rxrpc_init_peer(struct rxrpc_local * local,struct rxrpc_peer * peer,unsigned long hash_key)239 static void rxrpc_init_peer(struct rxrpc_local *local, struct rxrpc_peer *peer,
240 			    unsigned long hash_key)
241 {
242 	peer->hash_key = hash_key;
243 	rxrpc_assess_MTU_size(local, peer);
244 	peer->mtu = peer->if_mtu;
245 	peer->rtt_last_req = ktime_get_real();
246 
247 	switch (peer->srx.transport.family) {
248 	case AF_INET:
249 		peer->hdrsize = sizeof(struct iphdr);
250 		break;
251 #ifdef CONFIG_AF_RXRPC_IPV6
252 	case AF_INET6:
253 		peer->hdrsize = sizeof(struct ipv6hdr);
254 		break;
255 #endif
256 	default:
257 		BUG();
258 	}
259 
260 	switch (peer->srx.transport_type) {
261 	case SOCK_DGRAM:
262 		peer->hdrsize += sizeof(struct udphdr);
263 		break;
264 	default:
265 		BUG();
266 	}
267 
268 	peer->hdrsize += sizeof(struct rxrpc_wire_header);
269 	peer->maxdata = peer->mtu - peer->hdrsize;
270 }
271 
272 /*
273  * Set up a new peer.
274  */
rxrpc_create_peer(struct rxrpc_local * local,struct sockaddr_rxrpc * srx,unsigned long hash_key,gfp_t gfp)275 static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_local *local,
276 					    struct sockaddr_rxrpc *srx,
277 					    unsigned long hash_key,
278 					    gfp_t gfp)
279 {
280 	struct rxrpc_peer *peer;
281 
282 	_enter("");
283 
284 	peer = rxrpc_alloc_peer(local, gfp, rxrpc_peer_new_client);
285 	if (peer) {
286 		memcpy(&peer->srx, srx, sizeof(*srx));
287 		rxrpc_init_peer(local, peer, hash_key);
288 	}
289 
290 	_leave(" = %p", peer);
291 	return peer;
292 }
293 
rxrpc_free_peer(struct rxrpc_peer * peer)294 static void rxrpc_free_peer(struct rxrpc_peer *peer)
295 {
296 	trace_rxrpc_peer(peer->debug_id, 0, rxrpc_peer_free);
297 	rxrpc_put_local(peer->local, rxrpc_local_put_peer);
298 	kfree_rcu(peer, rcu);
299 }
300 
301 /*
302  * Set up a new incoming peer.  There shouldn't be any other matching peers
303  * since we've already done a search in the list from the non-reentrant context
304  * (the data_ready handler) that is the only place we can add new peers.
305  */
rxrpc_new_incoming_peer(struct rxrpc_local * local,struct rxrpc_peer * peer)306 void rxrpc_new_incoming_peer(struct rxrpc_local *local, struct rxrpc_peer *peer)
307 {
308 	struct rxrpc_net *rxnet = local->rxnet;
309 	unsigned long hash_key;
310 
311 	hash_key = rxrpc_peer_hash_key(local, &peer->srx);
312 	rxrpc_init_peer(local, peer, hash_key);
313 
314 	spin_lock(&rxnet->peer_hash_lock);
315 	hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key);
316 	list_add_tail(&peer->keepalive_link, &rxnet->peer_keepalive_new);
317 	spin_unlock(&rxnet->peer_hash_lock);
318 }
319 
320 /*
321  * obtain a remote transport endpoint for the specified address
322  */
rxrpc_lookup_peer(struct rxrpc_local * local,struct sockaddr_rxrpc * srx,gfp_t gfp)323 struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local,
324 				     struct sockaddr_rxrpc *srx, gfp_t gfp)
325 {
326 	struct rxrpc_peer *peer, *candidate;
327 	struct rxrpc_net *rxnet = local->rxnet;
328 	unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
329 
330 	_enter("{%pISp}", &srx->transport);
331 
332 	/* search the peer list first */
333 	rcu_read_lock();
334 	peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
335 	if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_lookup_client))
336 		peer = NULL;
337 	rcu_read_unlock();
338 
339 	if (!peer) {
340 		/* The peer is not yet present in hash - create a candidate
341 		 * for a new record and then redo the search.
342 		 */
343 		candidate = rxrpc_create_peer(local, srx, hash_key, gfp);
344 		if (!candidate) {
345 			_leave(" = NULL [nomem]");
346 			return NULL;
347 		}
348 
349 		spin_lock(&rxnet->peer_hash_lock);
350 
351 		/* Need to check that we aren't racing with someone else */
352 		peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
353 		if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_lookup_client))
354 			peer = NULL;
355 		if (!peer) {
356 			hash_add_rcu(rxnet->peer_hash,
357 				     &candidate->hash_link, hash_key);
358 			list_add_tail(&candidate->keepalive_link,
359 				      &rxnet->peer_keepalive_new);
360 		}
361 
362 		spin_unlock(&rxnet->peer_hash_lock);
363 
364 		if (peer)
365 			rxrpc_free_peer(candidate);
366 		else
367 			peer = candidate;
368 	}
369 
370 	_leave(" = %p {u=%d}", peer, refcount_read(&peer->ref));
371 	return peer;
372 }
373 
374 /*
375  * Get a ref on a peer record.
376  */
rxrpc_get_peer(struct rxrpc_peer * peer,enum rxrpc_peer_trace why)377 struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer, enum rxrpc_peer_trace why)
378 {
379 	int r;
380 
381 	__refcount_inc(&peer->ref, &r);
382 	trace_rxrpc_peer(peer->debug_id, r + 1, why);
383 	return peer;
384 }
385 
386 /*
387  * Get a ref on a peer record unless its usage has already reached 0.
388  */
rxrpc_get_peer_maybe(struct rxrpc_peer * peer,enum rxrpc_peer_trace why)389 struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer,
390 					enum rxrpc_peer_trace why)
391 {
392 	int r;
393 
394 	if (peer) {
395 		if (__refcount_inc_not_zero(&peer->ref, &r))
396 			trace_rxrpc_peer(peer->debug_id, r + 1, why);
397 		else
398 			peer = NULL;
399 	}
400 	return peer;
401 }
402 
403 /*
404  * Discard a peer record.
405  */
__rxrpc_put_peer(struct rxrpc_peer * peer)406 static void __rxrpc_put_peer(struct rxrpc_peer *peer)
407 {
408 	struct rxrpc_net *rxnet = peer->local->rxnet;
409 
410 	ASSERT(hlist_empty(&peer->error_targets));
411 
412 	spin_lock(&rxnet->peer_hash_lock);
413 	hash_del_rcu(&peer->hash_link);
414 	list_del_init(&peer->keepalive_link);
415 	spin_unlock(&rxnet->peer_hash_lock);
416 
417 	rxrpc_free_peer(peer);
418 }
419 
420 /*
421  * Drop a ref on a peer record.
422  */
rxrpc_put_peer(struct rxrpc_peer * peer,enum rxrpc_peer_trace why)423 void rxrpc_put_peer(struct rxrpc_peer *peer, enum rxrpc_peer_trace why)
424 {
425 	unsigned int debug_id;
426 	bool dead;
427 	int r;
428 
429 	if (peer) {
430 		debug_id = peer->debug_id;
431 		dead = __refcount_dec_and_test(&peer->ref, &r);
432 		trace_rxrpc_peer(debug_id, r - 1, why);
433 		if (dead)
434 			__rxrpc_put_peer(peer);
435 	}
436 }
437 
438 /*
439  * Make sure all peer records have been discarded.
440  */
rxrpc_destroy_all_peers(struct rxrpc_net * rxnet)441 void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet)
442 {
443 	struct rxrpc_peer *peer;
444 	int i;
445 
446 	for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) {
447 		if (hlist_empty(&rxnet->peer_hash[i]))
448 			continue;
449 
450 		hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) {
451 			pr_err("Leaked peer %u {%u} %pISp\n",
452 			       peer->debug_id,
453 			       refcount_read(&peer->ref),
454 			       &peer->srx.transport);
455 		}
456 	}
457 }
458 
459 /**
460  * rxrpc_kernel_get_peer - Get the peer address of a call
461  * @sock: The socket on which the call is in progress.
462  * @call: The call to query
463  * @_srx: Where to place the result
464  *
465  * Get the address of the remote peer in a call.
466  */
rxrpc_kernel_get_peer(struct socket * sock,struct rxrpc_call * call,struct sockaddr_rxrpc * _srx)467 void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call,
468 			   struct sockaddr_rxrpc *_srx)
469 {
470 	*_srx = call->peer->srx;
471 }
472 EXPORT_SYMBOL(rxrpc_kernel_get_peer);
473 
474 /**
475  * rxrpc_kernel_get_srtt - Get a call's peer smoothed RTT
476  * @sock: The socket on which the call is in progress.
477  * @call: The call to query
478  * @_srtt: Where to store the SRTT value.
479  *
480  * Get the call's peer smoothed RTT in uS.
481  */
rxrpc_kernel_get_srtt(struct socket * sock,struct rxrpc_call * call,u32 * _srtt)482 bool rxrpc_kernel_get_srtt(struct socket *sock, struct rxrpc_call *call,
483 			   u32 *_srtt)
484 {
485 	struct rxrpc_peer *peer = call->peer;
486 
487 	if (peer->rtt_count == 0) {
488 		*_srtt = 1000000; /* 1S */
489 		return false;
490 	}
491 
492 	*_srtt = call->peer->srtt_us >> 3;
493 	return true;
494 }
495 EXPORT_SYMBOL(rxrpc_kernel_get_srtt);
496