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TOMOYO Linux Cross Reference
Linux/net/rxrpc/peer_object.c

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  1 /* RxRPC remote transport endpoint record management
  2  *
  3  * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
  4  * Written by David Howells (dhowells@redhat.com)
  5  *
  6  * This program is free software; you can redistribute it and/or
  7  * modify it under the terms of the GNU General Public License
  8  * as published by the Free Software Foundation; either version
  9  * 2 of the License, or (at your option) any later version.
 10  */
 11 
 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 13 
 14 #include <linux/module.h>
 15 #include <linux/net.h>
 16 #include <linux/skbuff.h>
 17 #include <linux/udp.h>
 18 #include <linux/in.h>
 19 #include <linux/in6.h>
 20 #include <linux/slab.h>
 21 #include <linux/hashtable.h>
 22 #include <net/sock.h>
 23 #include <net/af_rxrpc.h>
 24 #include <net/ip.h>
 25 #include <net/route.h>
 26 #include <net/ip6_route.h>
 27 #include "ar-internal.h"
 28 
 29 /*
 30  * Hash a peer key.
 31  */
 32 static unsigned long rxrpc_peer_hash_key(struct rxrpc_local *local,
 33                                          const struct sockaddr_rxrpc *srx)
 34 {
 35         const u16 *p;
 36         unsigned int i, size;
 37         unsigned long hash_key;
 38 
 39         _enter("");
 40 
 41         hash_key = (unsigned long)local / __alignof__(*local);
 42         hash_key += srx->transport_type;
 43         hash_key += srx->transport_len;
 44         hash_key += srx->transport.family;
 45 
 46         switch (srx->transport.family) {
 47         case AF_INET:
 48                 hash_key += (u16 __force)srx->transport.sin.sin_port;
 49                 size = sizeof(srx->transport.sin.sin_addr);
 50                 p = (u16 *)&srx->transport.sin.sin_addr;
 51                 break;
 52 #ifdef CONFIG_AF_RXRPC_IPV6
 53         case AF_INET6:
 54                 hash_key += (u16 __force)srx->transport.sin.sin_port;
 55                 size = sizeof(srx->transport.sin6.sin6_addr);
 56                 p = (u16 *)&srx->transport.sin6.sin6_addr;
 57                 break;
 58 #endif
 59         default:
 60                 WARN(1, "AF_RXRPC: Unsupported transport address family\n");
 61                 return 0;
 62         }
 63 
 64         /* Step through the peer address in 16-bit portions for speed */
 65         for (i = 0; i < size; i += sizeof(*p), p++)
 66                 hash_key += *p;
 67 
 68         _leave(" 0x%lx", hash_key);
 69         return hash_key;
 70 }
 71 
 72 /*
 73  * Compare a peer to a key.  Return -ve, 0 or +ve to indicate less than, same
 74  * or greater than.
 75  *
 76  * Unfortunately, the primitives in linux/hashtable.h don't allow for sorted
 77  * buckets and mid-bucket insertion, so we don't make full use of this
 78  * information at this point.
 79  */
 80 static long rxrpc_peer_cmp_key(const struct rxrpc_peer *peer,
 81                                struct rxrpc_local *local,
 82                                const struct sockaddr_rxrpc *srx,
 83                                unsigned long hash_key)
 84 {
 85         long diff;
 86 
 87         diff = ((peer->hash_key - hash_key) ?:
 88                 ((unsigned long)peer->local - (unsigned long)local) ?:
 89                 (peer->srx.transport_type - srx->transport_type) ?:
 90                 (peer->srx.transport_len - srx->transport_len) ?:
 91                 (peer->srx.transport.family - srx->transport.family));
 92         if (diff != 0)
 93                 return diff;
 94 
 95         switch (srx->transport.family) {
 96         case AF_INET:
 97                 return ((u16 __force)peer->srx.transport.sin.sin_port -
 98                         (u16 __force)srx->transport.sin.sin_port) ?:
 99                         memcmp(&peer->srx.transport.sin.sin_addr,
100                                &srx->transport.sin.sin_addr,
101                                sizeof(struct in_addr));
102 #ifdef CONFIG_AF_RXRPC_IPV6
103         case AF_INET6:
104                 return ((u16 __force)peer->srx.transport.sin6.sin6_port -
105                         (u16 __force)srx->transport.sin6.sin6_port) ?:
106                         memcmp(&peer->srx.transport.sin6.sin6_addr,
107                                &srx->transport.sin6.sin6_addr,
108                                sizeof(struct in6_addr));
109 #endif
110         default:
111                 BUG();
112         }
113 }
114 
115 /*
116  * Look up a remote transport endpoint for the specified address using RCU.
117  */
118 static struct rxrpc_peer *__rxrpc_lookup_peer_rcu(
119         struct rxrpc_local *local,
120         const struct sockaddr_rxrpc *srx,
121         unsigned long hash_key)
122 {
123         struct rxrpc_peer *peer;
124         struct rxrpc_net *rxnet = local->rxnet;
125 
126         hash_for_each_possible_rcu(rxnet->peer_hash, peer, hash_link, hash_key) {
127                 if (rxrpc_peer_cmp_key(peer, local, srx, hash_key) == 0) {
128                         if (atomic_read(&peer->usage) == 0)
129                                 return NULL;
130                         return peer;
131                 }
132         }
133 
134         return NULL;
135 }
136 
137 /*
138  * Look up a remote transport endpoint for the specified address using RCU.
139  */
140 struct rxrpc_peer *rxrpc_lookup_peer_rcu(struct rxrpc_local *local,
141                                          const struct sockaddr_rxrpc *srx)
142 {
143         struct rxrpc_peer *peer;
144         unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
145 
146         peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
147         if (peer) {
148                 _net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
149                 _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
150         }
151         return peer;
152 }
153 
154 /*
155  * assess the MTU size for the network interface through which this peer is
156  * reached
157  */
158 static void rxrpc_assess_MTU_size(struct rxrpc_peer *peer)
159 {
160         struct dst_entry *dst;
161         struct rtable *rt;
162         struct flowi fl;
163         struct flowi4 *fl4 = &fl.u.ip4;
164 #ifdef CONFIG_AF_RXRPC_IPV6
165         struct flowi6 *fl6 = &fl.u.ip6;
166 #endif
167 
168         peer->if_mtu = 1500;
169 
170         memset(&fl, 0, sizeof(fl));
171         switch (peer->srx.transport.family) {
172         case AF_INET:
173                 rt = ip_route_output_ports(
174                         &init_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(&init_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         dst_release(dst);
207 
208         _leave(" [if_mtu %u]", peer->if_mtu);
209 }
210 
211 /*
212  * Allocate a peer.
213  */
214 struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp)
215 {
216         struct rxrpc_peer *peer;
217 
218         _enter("");
219 
220         peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
221         if (peer) {
222                 atomic_set(&peer->usage, 1);
223                 peer->local = local;
224                 INIT_HLIST_HEAD(&peer->error_targets);
225                 peer->service_conns = RB_ROOT;
226                 seqlock_init(&peer->service_conn_lock);
227                 spin_lock_init(&peer->lock);
228                 peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
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         }
237 
238         _leave(" = %p", peer);
239         return peer;
240 }
241 
242 /*
243  * Initialise peer record.
244  */
245 static void rxrpc_init_peer(struct rxrpc_peer *peer, unsigned long hash_key)
246 {
247         peer->hash_key = hash_key;
248         rxrpc_assess_MTU_size(peer);
249         peer->mtu = peer->if_mtu;
250         peer->rtt_last_req = ktime_get_real();
251 
252         switch (peer->srx.transport.family) {
253         case AF_INET:
254                 peer->hdrsize = sizeof(struct iphdr);
255                 break;
256 #ifdef CONFIG_AF_RXRPC_IPV6
257         case AF_INET6:
258                 peer->hdrsize = sizeof(struct ipv6hdr);
259                 break;
260 #endif
261         default:
262                 BUG();
263         }
264 
265         switch (peer->srx.transport_type) {
266         case SOCK_DGRAM:
267                 peer->hdrsize += sizeof(struct udphdr);
268                 break;
269         default:
270                 BUG();
271         }
272 
273         peer->hdrsize += sizeof(struct rxrpc_wire_header);
274         peer->maxdata = peer->mtu - peer->hdrsize;
275 }
276 
277 /*
278  * Set up a new peer.
279  */
280 static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_local *local,
281                                             struct sockaddr_rxrpc *srx,
282                                             unsigned long hash_key,
283                                             gfp_t gfp)
284 {
285         struct rxrpc_peer *peer;
286 
287         _enter("");
288 
289         peer = rxrpc_alloc_peer(local, gfp);
290         if (peer) {
291                 memcpy(&peer->srx, srx, sizeof(*srx));
292                 rxrpc_init_peer(peer, hash_key);
293         }
294 
295         _leave(" = %p", peer);
296         return peer;
297 }
298 
299 /*
300  * Set up a new incoming peer.  The address is prestored in the preallocated
301  * peer.
302  */
303 struct rxrpc_peer *rxrpc_lookup_incoming_peer(struct rxrpc_local *local,
304                                               struct rxrpc_peer *prealloc)
305 {
306         struct rxrpc_peer *peer;
307         struct rxrpc_net *rxnet = local->rxnet;
308         unsigned long hash_key;
309 
310         hash_key = rxrpc_peer_hash_key(local, &prealloc->srx);
311         prealloc->local = local;
312         rxrpc_init_peer(prealloc, hash_key);
313 
314         spin_lock(&rxnet->peer_hash_lock);
315 
316         /* Need to check that we aren't racing with someone else */
317         peer = __rxrpc_lookup_peer_rcu(local, &prealloc->srx, hash_key);
318         if (peer && !rxrpc_get_peer_maybe(peer))
319                 peer = NULL;
320         if (!peer) {
321                 peer = prealloc;
322                 hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key);
323                 list_add_tail(&peer->keepalive_link, &rxnet->peer_keepalive_new);
324         }
325 
326         spin_unlock(&rxnet->peer_hash_lock);
327         return peer;
328 }
329 
330 /*
331  * obtain a remote transport endpoint for the specified address
332  */
333 struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local,
334                                      struct sockaddr_rxrpc *srx, gfp_t gfp)
335 {
336         struct rxrpc_peer *peer, *candidate;
337         struct rxrpc_net *rxnet = local->rxnet;
338         unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
339 
340         _enter("{%pISp}", &srx->transport);
341 
342         /* search the peer list first */
343         rcu_read_lock();
344         peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
345         if (peer && !rxrpc_get_peer_maybe(peer))
346                 peer = NULL;
347         rcu_read_unlock();
348 
349         if (!peer) {
350                 /* The peer is not yet present in hash - create a candidate
351                  * for a new record and then redo the search.
352                  */
353                 candidate = rxrpc_create_peer(local, srx, hash_key, gfp);
354                 if (!candidate) {
355                         _leave(" = NULL [nomem]");
356                         return NULL;
357                 }
358 
359                 spin_lock_bh(&rxnet->peer_hash_lock);
360 
361                 /* Need to check that we aren't racing with someone else */
362                 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
363                 if (peer && !rxrpc_get_peer_maybe(peer))
364                         peer = NULL;
365                 if (!peer) {
366                         hash_add_rcu(rxnet->peer_hash,
367                                      &candidate->hash_link, hash_key);
368                         list_add_tail(&candidate->keepalive_link,
369                                       &rxnet->peer_keepalive_new);
370                 }
371 
372                 spin_unlock_bh(&rxnet->peer_hash_lock);
373 
374                 if (peer)
375                         kfree(candidate);
376                 else
377                         peer = candidate;
378         }
379 
380         _net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
381 
382         _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
383         return peer;
384 }
385 
386 /*
387  * Get a ref on a peer record.
388  */
389 struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer)
390 {
391         const void *here = __builtin_return_address(0);
392         int n;
393 
394         n = atomic_inc_return(&peer->usage);
395         trace_rxrpc_peer(peer, rxrpc_peer_got, n, here);
396         return peer;
397 }
398 
399 /*
400  * Get a ref on a peer record unless its usage has already reached 0.
401  */
402 struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer)
403 {
404         const void *here = __builtin_return_address(0);
405 
406         if (peer) {
407                 int n = __atomic_add_unless(&peer->usage, 1, 0);
408                 if (n > 0)
409                         trace_rxrpc_peer(peer, rxrpc_peer_got, n + 1, here);
410                 else
411                         peer = NULL;
412         }
413         return peer;
414 }
415 
416 /*
417  * Discard a peer record.
418  */
419 static void __rxrpc_put_peer(struct rxrpc_peer *peer)
420 {
421         struct rxrpc_net *rxnet = peer->local->rxnet;
422 
423         ASSERT(hlist_empty(&peer->error_targets));
424 
425         spin_lock_bh(&rxnet->peer_hash_lock);
426         hash_del_rcu(&peer->hash_link);
427         list_del_init(&peer->keepalive_link);
428         spin_unlock_bh(&rxnet->peer_hash_lock);
429 
430         kfree_rcu(peer, rcu);
431 }
432 
433 /*
434  * Drop a ref on a peer record.
435  */
436 void rxrpc_put_peer(struct rxrpc_peer *peer)
437 {
438         const void *here = __builtin_return_address(0);
439         int n;
440 
441         if (peer) {
442                 n = atomic_dec_return(&peer->usage);
443                 trace_rxrpc_peer(peer, rxrpc_peer_put, n, here);
444                 if (n == 0)
445                         __rxrpc_put_peer(peer);
446         }
447 }
448 
449 /*
450  * Make sure all peer records have been discarded.
451  */
452 void 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 %u {%u} %pISp\n",
463                                peer->debug_id,
464                                atomic_read(&peer->usage),
465                                &peer->srx.transport);
466                 }
467         }
468 }
469 
470 /**
471  * rxrpc_kernel_get_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  * @_srx: Where to place the result
475  *
476  * Get the address of the remote peer in a call.
477  */
478 void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call,
479                            struct sockaddr_rxrpc *_srx)
480 {
481         *_srx = call->peer->srx;
482 }
483 EXPORT_SYMBOL(rxrpc_kernel_get_peer);
484 
485 /**
486  * rxrpc_kernel_get_rtt - Get a call's peer RTT
487  * @sock: The socket on which the call is in progress.
488  * @call: The call to query
489  *
490  * Get the call's peer RTT.
491  */
492 u64 rxrpc_kernel_get_rtt(struct socket *sock, struct rxrpc_call *call)
493 {
494         return call->peer->rtt;
495 }
496 EXPORT_SYMBOL(rxrpc_kernel_get_rtt);
497 

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