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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 */
28static 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 */
76static 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 */
114static 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 */
134struct 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 */
150static 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 */
208struct 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 */
239static 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 */
275static 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
294static 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 */
306void 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 */
323struct 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 */
377struct 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 */
389struct 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 */
406static 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 */
423void 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 */
441void 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 */
467void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call,
468 struct sockaddr_rxrpc *_srx)
469{
470 *_srx = call->peer->srx;
471}
472EXPORT_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 */
482bool 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}
495EXPORT_SYMBOL(rxrpc_kernel_get_srtt);