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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                 INIT_WORK(&peer->error_distributor,
226                           &rxrpc_peer_error_distributor);
227                 peer->service_conns = RB_ROOT;
228                 seqlock_init(&peer->service_conn_lock);
229                 spin_lock_init(&peer->lock);
230                 peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
231 
232                 if (RXRPC_TX_SMSS > 2190)
233                         peer->cong_cwnd = 2;
234                 else if (RXRPC_TX_SMSS > 1095)
235                         peer->cong_cwnd = 3;
236                 else
237                         peer->cong_cwnd = 4;
238         }
239 
240         _leave(" = %p", peer);
241         return peer;
242 }
243 
244 /*
245  * Initialise peer record.
246  */
247 static void rxrpc_init_peer(struct rxrpc_peer *peer, unsigned long hash_key)
248 {
249         peer->hash_key = hash_key;
250         rxrpc_assess_MTU_size(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  */
282 static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_local *local,
283                                             struct sockaddr_rxrpc *srx,
284                                             unsigned long hash_key,
285                                             gfp_t gfp)
286 {
287         struct rxrpc_peer *peer;
288 
289         _enter("");
290 
291         peer = rxrpc_alloc_peer(local, gfp);
292         if (peer) {
293                 memcpy(&peer->srx, srx, sizeof(*srx));
294                 rxrpc_init_peer(peer, hash_key);
295         }
296 
297         _leave(" = %p", peer);
298         return peer;
299 }
300 
301 /*
302  * Set up a new incoming peer.  The address is prestored in the preallocated
303  * peer.
304  */
305 struct rxrpc_peer *rxrpc_lookup_incoming_peer(struct rxrpc_local *local,
306                                               struct rxrpc_peer *prealloc)
307 {
308         struct rxrpc_peer *peer;
309         struct rxrpc_net *rxnet = local->rxnet;
310         unsigned long hash_key;
311 
312         hash_key = rxrpc_peer_hash_key(local, &prealloc->srx);
313         prealloc->local = local;
314         rxrpc_init_peer(prealloc, hash_key);
315 
316         spin_lock(&rxnet->peer_hash_lock);
317 
318         /* Need to check that we aren't racing with someone else */
319         peer = __rxrpc_lookup_peer_rcu(local, &prealloc->srx, hash_key);
320         if (peer && !rxrpc_get_peer_maybe(peer))
321                 peer = NULL;
322         if (!peer) {
323                 peer = prealloc;
324                 hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key);
325         }
326 
327         spin_unlock(&rxnet->peer_hash_lock);
328         return peer;
329 }
330 
331 /*
332  * obtain a remote transport endpoint for the specified address
333  */
334 struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local,
335                                      struct sockaddr_rxrpc *srx, gfp_t gfp)
336 {
337         struct rxrpc_peer *peer, *candidate;
338         struct rxrpc_net *rxnet = local->rxnet;
339         unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
340 
341         _enter("{%pISp}", &srx->transport);
342 
343         /* search the peer list first */
344         rcu_read_lock();
345         peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
346         if (peer && !rxrpc_get_peer_maybe(peer))
347                 peer = NULL;
348         rcu_read_unlock();
349 
350         if (!peer) {
351                 /* The peer is not yet present in hash - create a candidate
352                  * for a new record and then redo the search.
353                  */
354                 candidate = rxrpc_create_peer(local, srx, hash_key, gfp);
355                 if (!candidate) {
356                         _leave(" = NULL [nomem]");
357                         return NULL;
358                 }
359 
360                 spin_lock_bh(&rxnet->peer_hash_lock);
361 
362                 /* Need to check that we aren't racing with someone else */
363                 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
364                 if (peer && !rxrpc_get_peer_maybe(peer))
365                         peer = NULL;
366                 if (!peer)
367                         hash_add_rcu(rxnet->peer_hash,
368                                      &candidate->hash_link, hash_key);
369 
370                 spin_unlock_bh(&rxnet->peer_hash_lock);
371 
372                 if (peer)
373                         kfree(candidate);
374                 else
375                         peer = candidate;
376         }
377 
378         _net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
379 
380         _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
381         return peer;
382 }
383 
384 /*
385  * Discard a ref on a remote peer record.
386  */
387 void __rxrpc_put_peer(struct rxrpc_peer *peer)
388 {
389         struct rxrpc_net *rxnet = peer->local->rxnet;
390 
391         ASSERT(hlist_empty(&peer->error_targets));
392 
393         spin_lock_bh(&rxnet->peer_hash_lock);
394         hash_del_rcu(&peer->hash_link);
395         spin_unlock_bh(&rxnet->peer_hash_lock);
396 
397         kfree_rcu(peer, rcu);
398 }
399 
400 /**
401  * rxrpc_kernel_get_peer - Get the peer address of a call
402  * @sock: The socket on which the call is in progress.
403  * @call: The call to query
404  * @_srx: Where to place the result
405  *
406  * Get the address of the remote peer in a call.
407  */
408 void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call,
409                            struct sockaddr_rxrpc *_srx)
410 {
411         *_srx = call->peer->srx;
412 }
413 EXPORT_SYMBOL(rxrpc_kernel_get_peer);
414 

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