peer_object.c

  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
 25static const struct sockaddr_rxrpc rxrpc_null_addr;
 26
 27/*
 28 * Hash a peer key.
 29 */
 30static unsigned long rxrpc_peer_hash_key(struct rxrpc_local *local,
 31					 const struct sockaddr_rxrpc *srx)
 32{
 33	const u16 *p;
 34	unsigned int i, size;
 35	unsigned long hash_key;
 36
 37	_enter("");
 38
 39	hash_key = (unsigned long)local / __alignof__(*local);
 40	hash_key += srx->transport_type;
 41	hash_key += srx->transport_len;
 42	hash_key += srx->transport.family;
 43
 44	switch (srx->transport.family) {
 45	case AF_INET:
 46		hash_key += (u16 __force)srx->transport.sin.sin_port;
 47		size = sizeof(srx->transport.sin.sin_addr);
 48		p = (u16 *)&srx->transport.sin.sin_addr;
 49		break;
 50#ifdef CONFIG_AF_RXRPC_IPV6
 51	case AF_INET6:
 52		hash_key += (u16 __force)srx->transport.sin.sin_port;
 53		size = sizeof(srx->transport.sin6.sin6_addr);
 54		p = (u16 *)&srx->transport.sin6.sin6_addr;
 55		break;
 56#endif
 57	default:
 58		WARN(1, "AF_RXRPC: Unsupported transport address family\n");
 59		return 0;
 60	}
 61
 62	/* Step through the peer address in 16-bit portions for speed */
 63	for (i = 0; i < size; i += sizeof(*p), p++)
 64		hash_key += *p;
 65
 66	_leave(" 0x%lx", hash_key);
 67	return hash_key;
 68}
 69
 70/*
 71 * Compare a peer to a key.  Return -ve, 0 or +ve to indicate less than, same
 72 * or greater than.
 73 *
 74 * Unfortunately, the primitives in linux/hashtable.h don't allow for sorted
 75 * buckets and mid-bucket insertion, so we don't make full use of this
 76 * information at this point.
 77 */
 78static long rxrpc_peer_cmp_key(const struct rxrpc_peer *peer,
 79			       struct rxrpc_local *local,
 80			       const struct sockaddr_rxrpc *srx,
 81			       unsigned long hash_key)
 82{
 83	long diff;
 84
 85	diff = ((peer->hash_key - hash_key) ?:
 86		((unsigned long)peer->local - (unsigned long)local) ?:
 87		(peer->srx.transport_type - srx->transport_type) ?:
 88		(peer->srx.transport_len - srx->transport_len) ?:
 89		(peer->srx.transport.family - srx->transport.family));
 90	if (diff != 0)
 91		return diff;
 92
 93	switch (srx->transport.family) {
 94	case AF_INET:
 95		return ((u16 __force)peer->srx.transport.sin.sin_port -
 96			(u16 __force)srx->transport.sin.sin_port) ?:
 97			memcmp(&peer->srx.transport.sin.sin_addr,
 98			       &srx->transport.sin.sin_addr,
 99			       sizeof(struct in_addr));
100#ifdef CONFIG_AF_RXRPC_IPV6
101	case AF_INET6:
102		return ((u16 __force)peer->srx.transport.sin6.sin6_port -
103			(u16 __force)srx->transport.sin6.sin6_port) ?:
104			memcmp(&peer->srx.transport.sin6.sin6_addr,
105			       &srx->transport.sin6.sin6_addr,
106			       sizeof(struct in6_addr));
107#endif
108	default:
109		BUG();
110	}
111}
112
113/*
114 * Look up a remote transport endpoint for the specified address using RCU.
115 */
116static struct rxrpc_peer *__rxrpc_lookup_peer_rcu(
117	struct rxrpc_local *local,
118	const struct sockaddr_rxrpc *srx,
119	unsigned long hash_key)
120{
121	struct rxrpc_peer *peer;
122	struct rxrpc_net *rxnet = local->rxnet;
123
124	hash_for_each_possible_rcu(rxnet->peer_hash, peer, hash_link, hash_key) {
125		if (rxrpc_peer_cmp_key(peer, local, srx, hash_key) == 0 &&
126		    refcount_read(&peer->ref) > 0)
127			return peer;
128	}
129
130	return NULL;
131}
132
133/*
134 * Look up a remote transport endpoint for the specified address using RCU.
135 */
136struct rxrpc_peer *rxrpc_lookup_peer_rcu(struct rxrpc_local *local,
137					 const struct sockaddr_rxrpc *srx)
138{
139	struct rxrpc_peer *peer;
140	unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
141
142	peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
143	if (peer)
144		_leave(" = %p {u=%d}", peer, refcount_read(&peer->ref));
145	return peer;
146}
147
148/*
149 * assess the MTU size for the network interface through which this peer is
150 * reached
151 */
152void rxrpc_assess_MTU_size(struct rxrpc_local *local, struct rxrpc_peer *peer)
153{
154	struct net *net = local->net;
155	struct dst_entry *dst;
156	struct rtable *rt;
157	struct flowi fl;
158	struct flowi4 *fl4 = &fl.u.ip4;
159#ifdef CONFIG_AF_RXRPC_IPV6
160	struct flowi6 *fl6 = &fl.u.ip6;
161#endif
162
163	peer->if_mtu = 1500;
164	if (peer->max_data < peer->if_mtu - peer->hdrsize) {
165		trace_rxrpc_pmtud_reduce(peer, 0, peer->if_mtu - peer->hdrsize,
166					 rxrpc_pmtud_reduce_route);
167		peer->max_data = peer->if_mtu - peer->hdrsize;
168	}
169
170	memset(&fl, 0, sizeof(fl));
171	switch (peer->srx.transport.family) {
172	case AF_INET:
173		rt = ip_route_output_ports(
174			net, fl4, NULL,
175			peer->srx.transport.sin.sin_addr.s_addr, 0,
176			htons(7000), htons(7001), IPPROTO_UDP, 0, 0);
177		if (IS_ERR(rt)) {
178			_leave(" [route err %ld]", PTR_ERR(rt));
179			return;
180		}
181		dst = &rt->dst;
182		break;
183
184#ifdef CONFIG_AF_RXRPC_IPV6
185	case AF_INET6:
186		fl6->flowi6_iif = LOOPBACK_IFINDEX;
187		fl6->flowi6_scope = RT_SCOPE_UNIVERSE;
188		fl6->flowi6_proto = IPPROTO_UDP;
189		memcpy(&fl6->daddr, &peer->srx.transport.sin6.sin6_addr,
190		       sizeof(struct in6_addr));
191		fl6->fl6_dport = htons(7001);
192		fl6->fl6_sport = htons(7000);
193		dst = ip6_route_output(net, NULL, fl6);
194		if (dst->error) {
195			_leave(" [route err %d]", dst->error);
196			return;
197		}
198		break;
199#endif
200
201	default:
202		BUG();
203	}
204
205	peer->if_mtu = dst_mtu(dst);
206	peer->hdrsize += dst->header_len + dst->trailer_len;
207	peer->tx_seg_max = dst->dev->gso_max_segs;
208	dst_release(dst);
209
210	peer->max_data		= umin(RXRPC_JUMBO(1), peer->if_mtu - peer->hdrsize);
211	peer->pmtud_good	= 500;
212	peer->pmtud_bad		= peer->if_mtu - peer->hdrsize + 1;
213	peer->pmtud_trial	= umin(peer->max_data, peer->pmtud_bad - 1);
214	peer->pmtud_pending	= true;
215
216	_leave(" [if_mtu %u]", peer->if_mtu);
217}
218
219/*
220 * Allocate a peer.
221 */
222struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp,
223				    enum rxrpc_peer_trace why)
224{
225	struct rxrpc_peer *peer;
226
227	_enter("");
228
229	peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
230	if (peer) {
231		refcount_set(&peer->ref, 1);
232		peer->local = rxrpc_get_local(local, rxrpc_local_get_peer);
233		INIT_HLIST_HEAD(&peer->error_targets);
234		peer->service_conns = RB_ROOT;
235		seqlock_init(&peer->service_conn_lock);
236		spin_lock_init(&peer->lock);
237		peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
238		peer->recent_srtt_us = UINT_MAX;
239		peer->cong_ssthresh = RXRPC_TX_MAX_WINDOW;
240		trace_rxrpc_peer(peer->debug_id, 1, why);
241	}
242
243	_leave(" = %p", peer);
244	return peer;
245}
246
247/*
248 * Initialise peer record.
249 */
250static void rxrpc_init_peer(struct rxrpc_local *local, struct rxrpc_peer *peer,
251			    unsigned long hash_key)
252{
253	peer->hash_key = hash_key;
254
255
256	switch (peer->srx.transport.family) {
257	case AF_INET:
258		peer->hdrsize = sizeof(struct iphdr);
259		break;
260#ifdef CONFIG_AF_RXRPC_IPV6
261	case AF_INET6:
262		peer->hdrsize = sizeof(struct ipv6hdr);
263		break;
264#endif
265	default:
266		BUG();
267	}
268
269	switch (peer->srx.transport_type) {
270	case SOCK_DGRAM:
271		peer->hdrsize += sizeof(struct udphdr);
272		break;
273	default:
274		BUG();
275	}
276
277	peer->hdrsize += sizeof(struct rxrpc_wire_header);
278	peer->max_data = peer->if_mtu - peer->hdrsize;
279}
280
281/*
282 * Set up a new peer.
283 */
284static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_local *local,
285					    struct sockaddr_rxrpc *srx,
286					    unsigned long hash_key,
287					    gfp_t gfp)
288{
289	struct rxrpc_peer *peer;
290
291	_enter("");
292
293	peer = rxrpc_alloc_peer(local, gfp, rxrpc_peer_new_client);
294	if (peer) {
295		memcpy(&peer->srx, srx, sizeof(*srx));
296		rxrpc_init_peer(local, peer, hash_key);
297		rxrpc_assess_MTU_size(local, peer);
298	}
299
300	_leave(" = %p", peer);
301	return peer;
302}
303
304static void rxrpc_free_peer(struct rxrpc_peer *peer)
305{
306	trace_rxrpc_peer(peer->debug_id, 0, rxrpc_peer_free);
307	rxrpc_put_local(peer->local, rxrpc_local_put_peer);
308	kfree_rcu(peer, rcu);
309}
310
311/*
312 * Set up a new incoming peer.  There shouldn't be any other matching peers
313 * since we've already done a search in the list from the non-reentrant context
314 * (the data_ready handler) that is the only place we can add new peers.
315 * Called with interrupts disabled.
316 */
317void rxrpc_new_incoming_peer(struct rxrpc_local *local, struct rxrpc_peer *peer)
318{
319	struct rxrpc_net *rxnet = local->rxnet;
320	unsigned long hash_key;
321
322	hash_key = rxrpc_peer_hash_key(local, &peer->srx);
323	rxrpc_init_peer(local, peer, hash_key);
324
325	spin_lock(&rxnet->peer_hash_lock);
326	hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key);
327	list_add_tail(&peer->keepalive_link, &rxnet->peer_keepalive_new);
328	spin_unlock(&rxnet->peer_hash_lock);
329}
330
331/*
332 * obtain a remote transport endpoint for the specified address
333 */
334struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local,
335				     struct sockaddr_rxrpc *srx, gfp_t gfp)
336{
337	struct rxrpc_peer *peer, *candidate;
338	struct rxrpc_net *rxnet = local->rxnet;
339	unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
340
341	_enter("{%pISp}", &srx->transport);
342
343	/* search the peer list first */
344	rcu_read_lock();
345	peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
346	if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_lookup_client))
347		peer = NULL;
348	rcu_read_unlock();
349
350	if (!peer) {
351		/* The peer is not yet present in hash - create a candidate
352		 * for a new record and then redo the search.
353		 */
354		candidate = rxrpc_create_peer(local, srx, hash_key, gfp);
355		if (!candidate) {
356			_leave(" = NULL [nomem]");
357			return NULL;
358		}
359
360		spin_lock_bh(&rxnet->peer_hash_lock);
361
362		/* Need to check that we aren't racing with someone else */
363		peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
364		if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_lookup_client))
365			peer = NULL;
366		if (!peer) {
367			hash_add_rcu(rxnet->peer_hash,
368				     &candidate->hash_link, hash_key);
369			list_add_tail(&candidate->keepalive_link,
370				      &rxnet->peer_keepalive_new);
371		}
372
373		spin_unlock_bh(&rxnet->peer_hash_lock);
374
375		if (peer)
376			rxrpc_free_peer(candidate);
377		else
378			peer = candidate;
379	}
380
381	_leave(" = %p {u=%d}", peer, refcount_read(&peer->ref));
382	return peer;
383}
384
385/*
386 * Get a ref on a peer record.
387 */
388struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer, enum rxrpc_peer_trace why)
389{
390	int r;
391
392	__refcount_inc(&peer->ref, &r);
393	trace_rxrpc_peer(peer->debug_id, r + 1, why);
394	return peer;
395}
396
397/*
398 * Get a ref on a peer record unless its usage has already reached 0.
399 */
400struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer,
401					enum rxrpc_peer_trace why)
402{
403	int r;
404
405	if (peer) {
406		if (__refcount_inc_not_zero(&peer->ref, &r))
407			trace_rxrpc_peer(peer->debug_id, r + 1, why);
408		else
409			peer = NULL;
410	}
411	return peer;
412}
413
414/*
415 * Discard a peer record.
416 */
417static void __rxrpc_put_peer(struct rxrpc_peer *peer)
418{
419	struct rxrpc_net *rxnet = peer->local->rxnet;
420
421	ASSERT(hlist_empty(&peer->error_targets));
422
423	spin_lock_bh(&rxnet->peer_hash_lock);
424	hash_del_rcu(&peer->hash_link);
425	list_del_init(&peer->keepalive_link);
426	spin_unlock_bh(&rxnet->peer_hash_lock);
427
428	rxrpc_free_peer(peer);
429}
430
431/*
432 * Drop a ref on a peer record.
433 */
434void rxrpc_put_peer(struct rxrpc_peer *peer, enum rxrpc_peer_trace why)
435{
436	unsigned int debug_id;
437	bool dead;
438	int r;
439
440	if (peer) {
441		debug_id = peer->debug_id;
442		dead = __refcount_dec_and_test(&peer->ref, &r);
443		trace_rxrpc_peer(debug_id, r - 1, why);
444		if (dead)
445			__rxrpc_put_peer(peer);
446	}
447}
448
449/*
450 * Make sure all peer records have been discarded.
451 */
452void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet)
453{
454	struct rxrpc_peer *peer;
455	int i;
456
457	for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) {
458		if (hlist_empty(&rxnet->peer_hash[i]))
459			continue;
460
461		hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) {
462			pr_err("Leaked peer %x {%u} %pISp\n",
463			       peer->debug_id,
464			       refcount_read(&peer->ref),
465			       &peer->srx.transport);
466		}
467	}
468}
469
470/**
471 * rxrpc_kernel_get_call_peer - Get the peer address of a call
472 * @sock: The socket on which the call is in progress.
473 * @call: The call to query
474 *
475 * Get a record for the remote peer in a call.
476 *
477 * Return: The call's peer record.
478 */
479struct rxrpc_peer *rxrpc_kernel_get_call_peer(struct socket *sock, struct rxrpc_call *call)
480{
481	return rxrpc_get_peer(call->peer, rxrpc_peer_get_application);
482}
483EXPORT_SYMBOL(rxrpc_kernel_get_call_peer);
484
485/**
486 * rxrpc_kernel_get_srtt - Get a call's peer smoothed RTT
487 * @peer: The peer to query
488 *
489 * Get the call's peer smoothed RTT.
490 *
491 * Return: The RTT in uS or %UINT_MAX if we have no samples.
492 */
493unsigned int rxrpc_kernel_get_srtt(const struct rxrpc_peer *peer)
494{
495	return READ_ONCE(peer->recent_srtt_us);
496}
497EXPORT_SYMBOL(rxrpc_kernel_get_srtt);
498
499/**
500 * rxrpc_kernel_remote_srx - Get the address of a peer
501 * @peer: The peer to query
502 *
503 * Get a pointer to the address from a peer record.  The caller is responsible
504 * for making sure that the address is not deallocated.  A fake address will be
505 * substituted if %peer in NULL.
506 *
507 * Return: The rxrpc address record or a fake record.
508 */
509const struct sockaddr_rxrpc *rxrpc_kernel_remote_srx(const struct rxrpc_peer *peer)
510{
511	return peer ? &peer->srx : &rxrpc_null_addr;
512}
513EXPORT_SYMBOL(rxrpc_kernel_remote_srx);
514
515/**
516 * rxrpc_kernel_remote_addr - Get the peer transport address of a call
517 * @peer: The peer to query
518 *
519 * Get a pointer to the transport address from a peer record.  The caller is
520 * responsible for making sure that the address is not deallocated.  A fake
521 * address will be substituted if %peer in NULL.
522 *
523 * Return: The transport address record or a fake record.
524 */
525const struct sockaddr *rxrpc_kernel_remote_addr(const struct rxrpc_peer *peer)
526{
527	return (const struct sockaddr *)
528		(peer ? &peer->srx.transport : &rxrpc_null_addr.transport);
529}
530EXPORT_SYMBOL(rxrpc_kernel_remote_addr);
531
532/**
533 * rxrpc_kernel_set_peer_data - Set app-specific data on a peer.
534 * @peer: The peer to alter
535 * @app_data: The data to set
536 *
537 * Set the app-specific data on a peer.  AF_RXRPC makes no effort to retain
538 * anything the data might refer to.
539 *
540 * Return: The previous app_data.
541 */
542unsigned long rxrpc_kernel_set_peer_data(struct rxrpc_peer *peer, unsigned long app_data)
543{
544	return xchg(&peer->app_data, app_data);
545}
546EXPORT_SYMBOL(rxrpc_kernel_set_peer_data);
547
548/**
549 * rxrpc_kernel_get_peer_data - Get app-specific data from a peer.
550 * @peer: The peer to query
551 *
552 * Retrieve the app-specific data from a peer.
553 *
554 * Return: The peer's app data.
555 */
556unsigned long rxrpc_kernel_get_peer_data(const struct rxrpc_peer *peer)
557{
558	return peer->app_data;
559}
560EXPORT_SYMBOL(rxrpc_kernel_get_peer_data);