xref: /openbmc/linux/net/rxrpc/peer_object.c (revision 9a87ffc99ec8eb8d35eed7c4f816d75f5cc9662e)
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