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 _net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
143 _leave(" = %p {u=%d}", peer, refcount_read(&peer->ref));
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 const void *here = __builtin_return_address(0);
213 struct rxrpc_peer *peer;
214
215 _enter("");
216
217 peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
218 if (peer) {
219 refcount_set(&peer->ref, 1);
220 peer->local = rxrpc_get_local(local);
221 INIT_HLIST_HEAD(&peer->error_targets);
222 peer->service_conns = RB_ROOT;
223 seqlock_init(&peer->service_conn_lock);
224 spin_lock_init(&peer->lock);
225 spin_lock_init(&peer->rtt_input_lock);
226 peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
227
228 rxrpc_peer_init_rtt(peer);
229
230 if (RXRPC_TX_SMSS > 2190)
231 peer->cong_cwnd = 2;
232 else if (RXRPC_TX_SMSS > 1095)
233 peer->cong_cwnd = 3;
234 else
235 peer->cong_cwnd = 4;
236 trace_rxrpc_peer(peer->debug_id, rxrpc_peer_new, 1, here);
237 }
238
239 _leave(" = %p", peer);
240 return peer;
241 }
242
243 /*
244 * Initialise peer record.
245 */
rxrpc_init_peer(struct rxrpc_sock * rx,struct rxrpc_peer * peer,unsigned long hash_key)246 static void rxrpc_init_peer(struct rxrpc_sock *rx, struct rxrpc_peer *peer,
247 unsigned long hash_key)
248 {
249 peer->hash_key = hash_key;
250 rxrpc_assess_MTU_size(rx, peer);
251 peer->mtu = peer->if_mtu;
252 peer->rtt_last_req = ktime_get_real();
253
254 switch (peer->srx.transport.family) {
255 case AF_INET:
256 peer->hdrsize = sizeof(struct iphdr);
257 break;
258 #ifdef CONFIG_AF_RXRPC_IPV6
259 case AF_INET6:
260 peer->hdrsize = sizeof(struct ipv6hdr);
261 break;
262 #endif
263 default:
264 BUG();
265 }
266
267 switch (peer->srx.transport_type) {
268 case SOCK_DGRAM:
269 peer->hdrsize += sizeof(struct udphdr);
270 break;
271 default:
272 BUG();
273 }
274
275 peer->hdrsize += sizeof(struct rxrpc_wire_header);
276 peer->maxdata = peer->mtu - peer->hdrsize;
277 }
278
279 /*
280 * Set up a new peer.
281 */
rxrpc_create_peer(struct rxrpc_sock * rx,struct rxrpc_local * local,struct sockaddr_rxrpc * srx,unsigned long hash_key,gfp_t gfp)282 static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_sock *rx,
283 struct rxrpc_local *local,
284 struct sockaddr_rxrpc *srx,
285 unsigned long hash_key,
286 gfp_t gfp)
287 {
288 struct rxrpc_peer *peer;
289
290 _enter("");
291
292 peer = rxrpc_alloc_peer(local, gfp);
293 if (peer) {
294 memcpy(&peer->srx, srx, sizeof(*srx));
295 rxrpc_init_peer(rx, peer, hash_key);
296 }
297
298 _leave(" = %p", peer);
299 return peer;
300 }
301
rxrpc_free_peer(struct rxrpc_peer * peer)302 static void rxrpc_free_peer(struct rxrpc_peer *peer)
303 {
304 rxrpc_put_local(peer->local);
305 kfree_rcu(peer, rcu);
306 }
307
308 /*
309 * Set up a new incoming peer. There shouldn't be any other matching peers
310 * since we've already done a search in the list from the non-reentrant context
311 * (the data_ready handler) that is the only place we can add new peers.
312 */
rxrpc_new_incoming_peer(struct rxrpc_sock * rx,struct rxrpc_local * local,struct rxrpc_peer * peer)313 void rxrpc_new_incoming_peer(struct rxrpc_sock *rx, struct rxrpc_local *local,
314 struct rxrpc_peer *peer)
315 {
316 struct rxrpc_net *rxnet = local->rxnet;
317 unsigned long hash_key;
318
319 hash_key = rxrpc_peer_hash_key(local, &peer->srx);
320 rxrpc_init_peer(rx, peer, hash_key);
321
322 spin_lock(&rxnet->peer_hash_lock);
323 hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key);
324 list_add_tail(&peer->keepalive_link, &rxnet->peer_keepalive_new);
325 spin_unlock(&rxnet->peer_hash_lock);
326 }
327
328 /*
329 * obtain a remote transport endpoint for the specified address
330 */
rxrpc_lookup_peer(struct rxrpc_sock * rx,struct rxrpc_local * local,struct sockaddr_rxrpc * srx,gfp_t gfp)331 struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_sock *rx,
332 struct rxrpc_local *local,
333 struct sockaddr_rxrpc *srx, gfp_t gfp)
334 {
335 struct rxrpc_peer *peer, *candidate;
336 struct rxrpc_net *rxnet = local->rxnet;
337 unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
338
339 _enter("{%pISp}", &srx->transport);
340
341 /* search the peer list first */
342 rcu_read_lock();
343 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
344 if (peer && !rxrpc_get_peer_maybe(peer))
345 peer = NULL;
346 rcu_read_unlock();
347
348 if (!peer) {
349 /* The peer is not yet present in hash - create a candidate
350 * for a new record and then redo the search.
351 */
352 candidate = rxrpc_create_peer(rx, local, srx, hash_key, gfp);
353 if (!candidate) {
354 _leave(" = NULL [nomem]");
355 return NULL;
356 }
357
358 spin_lock_bh(&rxnet->peer_hash_lock);
359
360 /* Need to check that we aren't racing with someone else */
361 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
362 if (peer && !rxrpc_get_peer_maybe(peer))
363 peer = NULL;
364 if (!peer) {
365 hash_add_rcu(rxnet->peer_hash,
366 &candidate->hash_link, hash_key);
367 list_add_tail(&candidate->keepalive_link,
368 &rxnet->peer_keepalive_new);
369 }
370
371 spin_unlock_bh(&rxnet->peer_hash_lock);
372
373 if (peer)
374 rxrpc_free_peer(candidate);
375 else
376 peer = candidate;
377 }
378
379 _net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
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 */
rxrpc_get_peer(struct rxrpc_peer * peer)388 struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer)
389 {
390 const void *here = __builtin_return_address(0);
391 int r;
392
393 __refcount_inc(&peer->ref, &r);
394 trace_rxrpc_peer(peer->debug_id, rxrpc_peer_got, r + 1, here);
395 return peer;
396 }
397
398 /*
399 * Get a ref on a peer record unless its usage has already reached 0.
400 */
rxrpc_get_peer_maybe(struct rxrpc_peer * peer)401 struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer)
402 {
403 const void *here = __builtin_return_address(0);
404 int r;
405
406 if (peer) {
407 if (__refcount_inc_not_zero(&peer->ref, &r))
408 trace_rxrpc_peer(peer->debug_id, rxrpc_peer_got, r + 1, here);
409 else
410 peer = NULL;
411 }
412 return peer;
413 }
414
415 /*
416 * Discard a peer record.
417 */
__rxrpc_put_peer(struct rxrpc_peer * peer)418 static void __rxrpc_put_peer(struct rxrpc_peer *peer)
419 {
420 struct rxrpc_net *rxnet = peer->local->rxnet;
421
422 ASSERT(hlist_empty(&peer->error_targets));
423
424 spin_lock_bh(&rxnet->peer_hash_lock);
425 hash_del_rcu(&peer->hash_link);
426 list_del_init(&peer->keepalive_link);
427 spin_unlock_bh(&rxnet->peer_hash_lock);
428
429 rxrpc_free_peer(peer);
430 }
431
432 /*
433 * Drop a ref on a peer record.
434 */
rxrpc_put_peer(struct rxrpc_peer * peer)435 void rxrpc_put_peer(struct rxrpc_peer *peer)
436 {
437 const void *here = __builtin_return_address(0);
438 unsigned int debug_id;
439 bool dead;
440 int r;
441
442 if (peer) {
443 debug_id = peer->debug_id;
444 dead = __refcount_dec_and_test(&peer->ref, &r);
445 trace_rxrpc_peer(debug_id, rxrpc_peer_put, r - 1, here);
446 if (dead)
447 __rxrpc_put_peer(peer);
448 }
449 }
450
451 /*
452 * Drop a ref on a peer record where the caller already holds the
453 * peer_hash_lock.
454 */
rxrpc_put_peer_locked(struct rxrpc_peer * peer)455 void rxrpc_put_peer_locked(struct rxrpc_peer *peer)
456 {
457 const void *here = __builtin_return_address(0);
458 unsigned int debug_id = peer->debug_id;
459 bool dead;
460 int r;
461
462 dead = __refcount_dec_and_test(&peer->ref, &r);
463 trace_rxrpc_peer(debug_id, rxrpc_peer_put, r - 1, here);
464 if (dead) {
465 hash_del_rcu(&peer->hash_link);
466 list_del_init(&peer->keepalive_link);
467 rxrpc_free_peer(peer);
468 }
469 }
470
471 /*
472 * Make sure all peer records have been discarded.
473 */
rxrpc_destroy_all_peers(struct rxrpc_net * rxnet)474 void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet)
475 {
476 struct rxrpc_peer *peer;
477 int i;
478
479 for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) {
480 if (hlist_empty(&rxnet->peer_hash[i]))
481 continue;
482
483 hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) {
484 pr_err("Leaked peer %u {%u} %pISp\n",
485 peer->debug_id,
486 refcount_read(&peer->ref),
487 &peer->srx.transport);
488 }
489 }
490 }
491
492 /**
493 * rxrpc_kernel_get_peer - Get the peer address of a call
494 * @sock: The socket on which the call is in progress.
495 * @call: The call to query
496 * @_srx: Where to place the result
497 *
498 * Get the address of the remote peer in a call.
499 */
rxrpc_kernel_get_peer(struct socket * sock,struct rxrpc_call * call,struct sockaddr_rxrpc * _srx)500 void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call,
501 struct sockaddr_rxrpc *_srx)
502 {
503 *_srx = call->peer->srx;
504 }
505 EXPORT_SYMBOL(rxrpc_kernel_get_peer);
506
507 /**
508 * rxrpc_kernel_get_srtt - Get a call's peer smoothed RTT
509 * @sock: The socket on which the call is in progress.
510 * @call: The call to query
511 * @_srtt: Where to store the SRTT value.
512 *
513 * Get the call's peer smoothed RTT in uS.
514 */
rxrpc_kernel_get_srtt(struct socket * sock,struct rxrpc_call * call,u32 * _srtt)515 bool rxrpc_kernel_get_srtt(struct socket *sock, struct rxrpc_call *call,
516 u32 *_srtt)
517 {
518 struct rxrpc_peer *peer = call->peer;
519
520 if (peer->rtt_count == 0) {
521 *_srtt = 1000000; /* 1S */
522 return false;
523 }
524
525 *_srtt = call->peer->srtt_us >> 3;
526 return true;
527 }
528 EXPORT_SYMBOL(rxrpc_kernel_get_srtt);
529