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 atomic_read(&peer->usage) > 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 _net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
143 _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
144 }
145 return peer;
146 }
147
148 /*
149 * assess the MTU size for the network interface through which this peer is
150 * reached
151 */
rxrpc_assess_MTU_size(struct rxrpc_sock * rx,struct rxrpc_peer * peer)152 static void rxrpc_assess_MTU_size(struct rxrpc_sock *rx,
153 struct rxrpc_peer *peer)
154 {
155 struct net *net = sock_net(&rx->sk);
156 struct dst_entry *dst;
157 struct rtable *rt;
158 struct flowi fl;
159 struct flowi4 *fl4 = &fl.u.ip4;
160 #ifdef CONFIG_AF_RXRPC_IPV6
161 struct flowi6 *fl6 = &fl.u.ip6;
162 #endif
163
164 peer->if_mtu = 1500;
165
166 memset(&fl, 0, sizeof(fl));
167 switch (peer->srx.transport.family) {
168 case AF_INET:
169 rt = ip_route_output_ports(
170 net, fl4, NULL,
171 peer->srx.transport.sin.sin_addr.s_addr, 0,
172 htons(7000), htons(7001), IPPROTO_UDP, 0, 0);
173 if (IS_ERR(rt)) {
174 _leave(" [route err %ld]", PTR_ERR(rt));
175 return;
176 }
177 dst = &rt->dst;
178 break;
179
180 #ifdef CONFIG_AF_RXRPC_IPV6
181 case AF_INET6:
182 fl6->flowi6_iif = LOOPBACK_IFINDEX;
183 fl6->flowi6_scope = RT_SCOPE_UNIVERSE;
184 fl6->flowi6_proto = IPPROTO_UDP;
185 memcpy(&fl6->daddr, &peer->srx.transport.sin6.sin6_addr,
186 sizeof(struct in6_addr));
187 fl6->fl6_dport = htons(7001);
188 fl6->fl6_sport = htons(7000);
189 dst = ip6_route_output(net, NULL, fl6);
190 if (dst->error) {
191 _leave(" [route err %d]", dst->error);
192 return;
193 }
194 break;
195 #endif
196
197 default:
198 BUG();
199 }
200
201 peer->if_mtu = dst_mtu(dst);
202 dst_release(dst);
203
204 _leave(" [if_mtu %u]", peer->if_mtu);
205 }
206
207 /*
208 * Allocate a peer.
209 */
rxrpc_alloc_peer(struct rxrpc_local * local,gfp_t gfp)210 struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp)
211 {
212 struct rxrpc_peer *peer;
213
214 _enter("");
215
216 peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
217 if (peer) {
218 atomic_set(&peer->usage, 1);
219 peer->local = rxrpc_get_local(local);
220 INIT_HLIST_HEAD(&peer->error_targets);
221 peer->service_conns = RB_ROOT;
222 seqlock_init(&peer->service_conn_lock);
223 spin_lock_init(&peer->lock);
224 spin_lock_init(&peer->rtt_input_lock);
225 peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
226
227 if (RXRPC_TX_SMSS > 2190)
228 peer->cong_cwnd = 2;
229 else if (RXRPC_TX_SMSS > 1095)
230 peer->cong_cwnd = 3;
231 else
232 peer->cong_cwnd = 4;
233 }
234
235 _leave(" = %p", peer);
236 return peer;
237 }
238
239 /*
240 * Initialise peer record.
241 */
rxrpc_init_peer(struct rxrpc_sock * rx,struct rxrpc_peer * peer,unsigned long hash_key)242 static void rxrpc_init_peer(struct rxrpc_sock *rx, struct rxrpc_peer *peer,
243 unsigned long hash_key)
244 {
245 peer->hash_key = hash_key;
246 rxrpc_assess_MTU_size(rx, peer);
247 peer->mtu = peer->if_mtu;
248 peer->rtt_last_req = ktime_get_real();
249
250 switch (peer->srx.transport.family) {
251 case AF_INET:
252 peer->hdrsize = sizeof(struct iphdr);
253 break;
254 #ifdef CONFIG_AF_RXRPC_IPV6
255 case AF_INET6:
256 peer->hdrsize = sizeof(struct ipv6hdr);
257 break;
258 #endif
259 default:
260 BUG();
261 }
262
263 switch (peer->srx.transport_type) {
264 case SOCK_DGRAM:
265 peer->hdrsize += sizeof(struct udphdr);
266 break;
267 default:
268 BUG();
269 }
270
271 peer->hdrsize += sizeof(struct rxrpc_wire_header);
272 peer->maxdata = peer->mtu - peer->hdrsize;
273 }
274
275 /*
276 * Set up a new peer.
277 */
rxrpc_create_peer(struct rxrpc_sock * rx,struct rxrpc_local * local,struct sockaddr_rxrpc * srx,unsigned long hash_key,gfp_t gfp)278 static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_sock *rx,
279 struct rxrpc_local *local,
280 struct sockaddr_rxrpc *srx,
281 unsigned long hash_key,
282 gfp_t gfp)
283 {
284 struct rxrpc_peer *peer;
285
286 _enter("");
287
288 peer = rxrpc_alloc_peer(local, gfp);
289 if (peer) {
290 memcpy(&peer->srx, srx, sizeof(*srx));
291 rxrpc_init_peer(rx, peer, hash_key);
292 }
293
294 _leave(" = %p", peer);
295 return peer;
296 }
297
298 /*
299 * Set up a new incoming peer. There shouldn't be any other matching peers
300 * since we've already done a search in the list from the non-reentrant context
301 * (the data_ready handler) that is the only place we can add new peers.
302 */
rxrpc_new_incoming_peer(struct rxrpc_sock * rx,struct rxrpc_local * local,struct rxrpc_peer * peer)303 void rxrpc_new_incoming_peer(struct rxrpc_sock *rx, struct rxrpc_local *local,
304 struct rxrpc_peer *peer)
305 {
306 struct rxrpc_net *rxnet = local->rxnet;
307 unsigned long hash_key;
308
309 hash_key = rxrpc_peer_hash_key(local, &peer->srx);
310 rxrpc_init_peer(rx, peer, hash_key);
311
312 spin_lock(&rxnet->peer_hash_lock);
313 hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key);
314 list_add_tail(&peer->keepalive_link, &rxnet->peer_keepalive_new);
315 spin_unlock(&rxnet->peer_hash_lock);
316 }
317
318 /*
319 * obtain a remote transport endpoint for the specified address
320 */
rxrpc_lookup_peer(struct rxrpc_sock * rx,struct rxrpc_local * local,struct sockaddr_rxrpc * srx,gfp_t gfp)321 struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_sock *rx,
322 struct rxrpc_local *local,
323 struct sockaddr_rxrpc *srx, gfp_t gfp)
324 {
325 struct rxrpc_peer *peer, *candidate;
326 struct rxrpc_net *rxnet = local->rxnet;
327 unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
328
329 _enter("{%pISp}", &srx->transport);
330
331 /* search the peer list first */
332 rcu_read_lock();
333 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
334 if (peer && !rxrpc_get_peer_maybe(peer))
335 peer = NULL;
336 rcu_read_unlock();
337
338 if (!peer) {
339 /* The peer is not yet present in hash - create a candidate
340 * for a new record and then redo the search.
341 */
342 candidate = rxrpc_create_peer(rx, local, srx, hash_key, gfp);
343 if (!candidate) {
344 _leave(" = NULL [nomem]");
345 return NULL;
346 }
347
348 spin_lock_bh(&rxnet->peer_hash_lock);
349
350 /* Need to check that we aren't racing with someone else */
351 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
352 if (peer && !rxrpc_get_peer_maybe(peer))
353 peer = NULL;
354 if (!peer) {
355 hash_add_rcu(rxnet->peer_hash,
356 &candidate->hash_link, hash_key);
357 list_add_tail(&candidate->keepalive_link,
358 &rxnet->peer_keepalive_new);
359 }
360
361 spin_unlock_bh(&rxnet->peer_hash_lock);
362
363 if (peer)
364 kfree(candidate);
365 else
366 peer = candidate;
367 }
368
369 _net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
370
371 _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
372 return peer;
373 }
374
375 /*
376 * Get a ref on a peer record.
377 */
rxrpc_get_peer(struct rxrpc_peer * peer)378 struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer)
379 {
380 const void *here = __builtin_return_address(0);
381 int n;
382
383 n = atomic_inc_return(&peer->usage);
384 trace_rxrpc_peer(peer->debug_id, rxrpc_peer_got, n, here);
385 return peer;
386 }
387
388 /*
389 * Get a ref on a peer record unless its usage has already reached 0.
390 */
rxrpc_get_peer_maybe(struct rxrpc_peer * peer)391 struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer)
392 {
393 const void *here = __builtin_return_address(0);
394
395 if (peer) {
396 int n = atomic_fetch_add_unless(&peer->usage, 1, 0);
397 if (n > 0)
398 trace_rxrpc_peer(peer->debug_id, rxrpc_peer_got, n + 1, here);
399 else
400 peer = NULL;
401 }
402 return peer;
403 }
404
405 /*
406 * Discard a peer record.
407 */
__rxrpc_put_peer(struct rxrpc_peer * peer)408 static void __rxrpc_put_peer(struct rxrpc_peer *peer)
409 {
410 struct rxrpc_net *rxnet = peer->local->rxnet;
411
412 ASSERT(hlist_empty(&peer->error_targets));
413
414 spin_lock_bh(&rxnet->peer_hash_lock);
415 hash_del_rcu(&peer->hash_link);
416 list_del_init(&peer->keepalive_link);
417 spin_unlock_bh(&rxnet->peer_hash_lock);
418
419 rxrpc_put_local(peer->local);
420 kfree_rcu(peer, rcu);
421 }
422
423 /*
424 * Drop a ref on a peer record.
425 */
rxrpc_put_peer(struct rxrpc_peer * peer)426 void rxrpc_put_peer(struct rxrpc_peer *peer)
427 {
428 const void *here = __builtin_return_address(0);
429 unsigned int debug_id;
430 int n;
431
432 if (peer) {
433 debug_id = peer->debug_id;
434 n = atomic_dec_return(&peer->usage);
435 trace_rxrpc_peer(debug_id, rxrpc_peer_put, n, here);
436 if (n == 0)
437 __rxrpc_put_peer(peer);
438 }
439 }
440
441 /*
442 * Drop a ref on a peer record where the caller already holds the
443 * peer_hash_lock.
444 */
rxrpc_put_peer_locked(struct rxrpc_peer * peer)445 void rxrpc_put_peer_locked(struct rxrpc_peer *peer)
446 {
447 const void *here = __builtin_return_address(0);
448 unsigned int debug_id = peer->debug_id;
449 int n;
450
451 n = atomic_dec_return(&peer->usage);
452 trace_rxrpc_peer(debug_id, rxrpc_peer_put, n, here);
453 if (n == 0) {
454 hash_del_rcu(&peer->hash_link);
455 list_del_init(&peer->keepalive_link);
456 rxrpc_put_local(peer->local);
457 kfree_rcu(peer, rcu);
458 }
459 }
460
461 /*
462 * Make sure all peer records have been discarded.
463 */
rxrpc_destroy_all_peers(struct rxrpc_net * rxnet)464 void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet)
465 {
466 struct rxrpc_peer *peer;
467 int i;
468
469 for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) {
470 if (hlist_empty(&rxnet->peer_hash[i]))
471 continue;
472
473 hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) {
474 pr_err("Leaked peer %u {%u} %pISp\n",
475 peer->debug_id,
476 atomic_read(&peer->usage),
477 &peer->srx.transport);
478 }
479 }
480 }
481
482 /**
483 * rxrpc_kernel_get_peer - Get the peer address of a call
484 * @sock: The socket on which the call is in progress.
485 * @call: The call to query
486 * @_srx: Where to place the result
487 *
488 * Get the address of the remote peer in a call.
489 */
rxrpc_kernel_get_peer(struct socket * sock,struct rxrpc_call * call,struct sockaddr_rxrpc * _srx)490 void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call,
491 struct sockaddr_rxrpc *_srx)
492 {
493 *_srx = call->peer->srx;
494 }
495 EXPORT_SYMBOL(rxrpc_kernel_get_peer);
496
497 /**
498 * rxrpc_kernel_get_rtt - Get a call's peer RTT
499 * @sock: The socket on which the call is in progress.
500 * @call: The call to query
501 *
502 * Get the call's peer RTT.
503 */
rxrpc_kernel_get_rtt(struct socket * sock,struct rxrpc_call * call)504 u64 rxrpc_kernel_get_rtt(struct socket *sock, struct rxrpc_call *call)
505 {
506 return call->peer->rtt;
507 }
508 EXPORT_SYMBOL(rxrpc_kernel_get_rtt);
509