1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Local endpoint object management
3 *
4 * Copyright (C) 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/slab.h>
14 #include <linux/udp.h>
15 #include <linux/ip.h>
16 #include <linux/hashtable.h>
17 #include <net/sock.h>
18 #include <net/udp.h>
19 #include <net/af_rxrpc.h>
20 #include "ar-internal.h"
21
22 static void rxrpc_local_processor(struct work_struct *);
23 static void rxrpc_local_rcu(struct rcu_head *);
24
25 /*
26 * Compare a local to an address. Return -ve, 0 or +ve to indicate less than,
27 * same or greater than.
28 *
29 * We explicitly don't compare the RxRPC service ID as we want to reject
30 * conflicting uses by differing services. Further, we don't want to share
31 * addresses with different options (IPv6), so we don't compare those bits
32 * either.
33 */
rxrpc_local_cmp_key(const struct rxrpc_local * local,const struct sockaddr_rxrpc * srx)34 static long rxrpc_local_cmp_key(const struct rxrpc_local *local,
35 const struct sockaddr_rxrpc *srx)
36 {
37 long diff;
38
39 diff = ((local->srx.transport_type - srx->transport_type) ?:
40 (local->srx.transport_len - srx->transport_len) ?:
41 (local->srx.transport.family - srx->transport.family));
42 if (diff != 0)
43 return diff;
44
45 switch (srx->transport.family) {
46 case AF_INET:
47 /* If the choice of UDP port is left up to the transport, then
48 * the endpoint record doesn't match.
49 */
50 return ((u16 __force)local->srx.transport.sin.sin_port -
51 (u16 __force)srx->transport.sin.sin_port) ?:
52 memcmp(&local->srx.transport.sin.sin_addr,
53 &srx->transport.sin.sin_addr,
54 sizeof(struct in_addr));
55 #ifdef CONFIG_AF_RXRPC_IPV6
56 case AF_INET6:
57 /* If the choice of UDP6 port is left up to the transport, then
58 * the endpoint record doesn't match.
59 */
60 return ((u16 __force)local->srx.transport.sin6.sin6_port -
61 (u16 __force)srx->transport.sin6.sin6_port) ?:
62 memcmp(&local->srx.transport.sin6.sin6_addr,
63 &srx->transport.sin6.sin6_addr,
64 sizeof(struct in6_addr));
65 #endif
66 default:
67 BUG();
68 }
69 }
70
71 /*
72 * Allocate a new local endpoint.
73 */
rxrpc_alloc_local(struct rxrpc_net * rxnet,const struct sockaddr_rxrpc * srx)74 static struct rxrpc_local *rxrpc_alloc_local(struct rxrpc_net *rxnet,
75 const struct sockaddr_rxrpc *srx)
76 {
77 struct rxrpc_local *local;
78
79 local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL);
80 if (local) {
81 atomic_set(&local->usage, 1);
82 atomic_set(&local->active_users, 1);
83 local->rxnet = rxnet;
84 INIT_LIST_HEAD(&local->link);
85 INIT_WORK(&local->processor, rxrpc_local_processor);
86 init_rwsem(&local->defrag_sem);
87 skb_queue_head_init(&local->reject_queue);
88 skb_queue_head_init(&local->event_queue);
89 local->client_conns = RB_ROOT;
90 spin_lock_init(&local->client_conns_lock);
91 spin_lock_init(&local->lock);
92 rwlock_init(&local->services_lock);
93 local->debug_id = atomic_inc_return(&rxrpc_debug_id);
94 memcpy(&local->srx, srx, sizeof(*srx));
95 local->srx.srx_service = 0;
96 trace_rxrpc_local(local->debug_id, rxrpc_local_new, 1, NULL);
97 }
98
99 _leave(" = %p", local);
100 return local;
101 }
102
103 /*
104 * create the local socket
105 * - must be called with rxrpc_local_mutex locked
106 */
rxrpc_open_socket(struct rxrpc_local * local,struct net * net)107 static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net)
108 {
109 struct sock *usk;
110 int ret, opt;
111
112 _enter("%p{%d,%d}",
113 local, local->srx.transport_type, local->srx.transport.family);
114
115 /* create a socket to represent the local endpoint */
116 ret = sock_create_kern(net, local->srx.transport.family,
117 local->srx.transport_type, 0, &local->socket);
118 if (ret < 0) {
119 _leave(" = %d [socket]", ret);
120 return ret;
121 }
122
123 /* set the socket up */
124 usk = local->socket->sk;
125 inet_sk(usk)->mc_loop = 0;
126
127 /* Enable CHECKSUM_UNNECESSARY to CHECKSUM_COMPLETE conversion */
128 inet_inc_convert_csum(usk);
129
130 rcu_assign_sk_user_data(usk, local);
131
132 udp_sk(usk)->encap_type = UDP_ENCAP_RXRPC;
133 udp_sk(usk)->encap_rcv = rxrpc_input_packet;
134 udp_sk(usk)->encap_destroy = NULL;
135 udp_sk(usk)->gro_receive = NULL;
136 udp_sk(usk)->gro_complete = NULL;
137
138 udp_encap_enable();
139 #if IS_ENABLED(CONFIG_AF_RXRPC_IPV6)
140 if (local->srx.transport.family == AF_INET6)
141 udpv6_encap_enable();
142 #endif
143 usk->sk_error_report = rxrpc_error_report;
144
145 /* if a local address was supplied then bind it */
146 if (local->srx.transport_len > sizeof(sa_family_t)) {
147 _debug("bind");
148 ret = kernel_bind(local->socket,
149 (struct sockaddr *)&local->srx.transport,
150 local->srx.transport_len);
151 if (ret < 0) {
152 _debug("bind failed %d", ret);
153 goto error;
154 }
155 }
156
157 switch (local->srx.transport.family) {
158 case AF_INET6:
159 /* we want to receive ICMPv6 errors */
160 opt = 1;
161 ret = kernel_setsockopt(local->socket, SOL_IPV6, IPV6_RECVERR,
162 (char *) &opt, sizeof(opt));
163 if (ret < 0) {
164 _debug("setsockopt failed");
165 goto error;
166 }
167
168 /* Fall through and set IPv4 options too otherwise we don't get
169 * errors from IPv4 packets sent through the IPv6 socket.
170 */
171 /* Fall through */
172 case AF_INET:
173 /* we want to receive ICMP errors */
174 opt = 1;
175 ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR,
176 (char *) &opt, sizeof(opt));
177 if (ret < 0) {
178 _debug("setsockopt failed");
179 goto error;
180 }
181
182 /* we want to set the don't fragment bit */
183 opt = IP_PMTUDISC_DO;
184 ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER,
185 (char *) &opt, sizeof(opt));
186 if (ret < 0) {
187 _debug("setsockopt failed");
188 goto error;
189 }
190
191 /* We want receive timestamps. */
192 opt = 1;
193 ret = kernel_setsockopt(local->socket, SOL_SOCKET, SO_TIMESTAMPNS_OLD,
194 (char *)&opt, sizeof(opt));
195 if (ret < 0) {
196 _debug("setsockopt failed");
197 goto error;
198 }
199 break;
200
201 default:
202 BUG();
203 }
204
205 _leave(" = 0");
206 return 0;
207
208 error:
209 kernel_sock_shutdown(local->socket, SHUT_RDWR);
210 local->socket->sk->sk_user_data = NULL;
211 sock_release(local->socket);
212 local->socket = NULL;
213
214 _leave(" = %d", ret);
215 return ret;
216 }
217
218 /*
219 * Look up or create a new local endpoint using the specified local address.
220 */
rxrpc_lookup_local(struct net * net,const struct sockaddr_rxrpc * srx)221 struct rxrpc_local *rxrpc_lookup_local(struct net *net,
222 const struct sockaddr_rxrpc *srx)
223 {
224 struct rxrpc_local *local;
225 struct rxrpc_net *rxnet = rxrpc_net(net);
226 struct list_head *cursor;
227 const char *age;
228 long diff;
229 int ret;
230
231 _enter("{%d,%d,%pISp}",
232 srx->transport_type, srx->transport.family, &srx->transport);
233
234 mutex_lock(&rxnet->local_mutex);
235
236 for (cursor = rxnet->local_endpoints.next;
237 cursor != &rxnet->local_endpoints;
238 cursor = cursor->next) {
239 local = list_entry(cursor, struct rxrpc_local, link);
240
241 diff = rxrpc_local_cmp_key(local, srx);
242 if (diff < 0)
243 continue;
244 if (diff > 0)
245 break;
246
247 /* Services aren't allowed to share transport sockets, so
248 * reject that here. It is possible that the object is dying -
249 * but it may also still have the local transport address that
250 * we want bound.
251 */
252 if (srx->srx_service) {
253 local = NULL;
254 goto addr_in_use;
255 }
256
257 /* Found a match. We replace a dying object. Attempting to
258 * bind the transport socket may still fail if we're attempting
259 * to use a local address that the dying object is still using.
260 */
261 if (!rxrpc_use_local(local))
262 break;
263
264 age = "old";
265 goto found;
266 }
267
268 local = rxrpc_alloc_local(rxnet, srx);
269 if (!local)
270 goto nomem;
271
272 ret = rxrpc_open_socket(local, net);
273 if (ret < 0)
274 goto sock_error;
275
276 if (cursor != &rxnet->local_endpoints)
277 list_replace_init(cursor, &local->link);
278 else
279 list_add_tail(&local->link, cursor);
280 age = "new";
281
282 found:
283 mutex_unlock(&rxnet->local_mutex);
284
285 _net("LOCAL %s %d {%pISp}",
286 age, local->debug_id, &local->srx.transport);
287
288 _leave(" = %p", local);
289 return local;
290
291 nomem:
292 ret = -ENOMEM;
293 sock_error:
294 mutex_unlock(&rxnet->local_mutex);
295 if (local)
296 call_rcu(&local->rcu, rxrpc_local_rcu);
297 _leave(" = %d", ret);
298 return ERR_PTR(ret);
299
300 addr_in_use:
301 mutex_unlock(&rxnet->local_mutex);
302 _leave(" = -EADDRINUSE");
303 return ERR_PTR(-EADDRINUSE);
304 }
305
306 /*
307 * Get a ref on a local endpoint.
308 */
rxrpc_get_local(struct rxrpc_local * local)309 struct rxrpc_local *rxrpc_get_local(struct rxrpc_local *local)
310 {
311 const void *here = __builtin_return_address(0);
312 int n;
313
314 n = atomic_inc_return(&local->usage);
315 trace_rxrpc_local(local->debug_id, rxrpc_local_got, n, here);
316 return local;
317 }
318
319 /*
320 * Get a ref on a local endpoint unless its usage has already reached 0.
321 */
rxrpc_get_local_maybe(struct rxrpc_local * local)322 struct rxrpc_local *rxrpc_get_local_maybe(struct rxrpc_local *local)
323 {
324 const void *here = __builtin_return_address(0);
325
326 if (local) {
327 int n = atomic_fetch_add_unless(&local->usage, 1, 0);
328 if (n > 0)
329 trace_rxrpc_local(local->debug_id, rxrpc_local_got,
330 n + 1, here);
331 else
332 local = NULL;
333 }
334 return local;
335 }
336
337 /*
338 * Queue a local endpoint and pass the caller's reference to the work item.
339 */
rxrpc_queue_local(struct rxrpc_local * local)340 void rxrpc_queue_local(struct rxrpc_local *local)
341 {
342 const void *here = __builtin_return_address(0);
343 unsigned int debug_id = local->debug_id;
344 int n = atomic_read(&local->usage);
345
346 if (rxrpc_queue_work(&local->processor))
347 trace_rxrpc_local(debug_id, rxrpc_local_queued, n, here);
348 else
349 rxrpc_put_local(local);
350 }
351
352 /*
353 * Drop a ref on a local endpoint.
354 */
rxrpc_put_local(struct rxrpc_local * local)355 void rxrpc_put_local(struct rxrpc_local *local)
356 {
357 const void *here = __builtin_return_address(0);
358 unsigned int debug_id;
359 int n;
360
361 if (local) {
362 debug_id = local->debug_id;
363
364 n = atomic_dec_return(&local->usage);
365 trace_rxrpc_local(debug_id, rxrpc_local_put, n, here);
366
367 if (n == 0)
368 call_rcu(&local->rcu, rxrpc_local_rcu);
369 }
370 }
371
372 /*
373 * Start using a local endpoint.
374 */
rxrpc_use_local(struct rxrpc_local * local)375 struct rxrpc_local *rxrpc_use_local(struct rxrpc_local *local)
376 {
377 local = rxrpc_get_local_maybe(local);
378 if (!local)
379 return NULL;
380
381 if (!__rxrpc_use_local(local)) {
382 rxrpc_put_local(local);
383 return NULL;
384 }
385
386 return local;
387 }
388
389 /*
390 * Cease using a local endpoint. Once the number of active users reaches 0, we
391 * start the closure of the transport in the work processor.
392 */
rxrpc_unuse_local(struct rxrpc_local * local)393 void rxrpc_unuse_local(struct rxrpc_local *local)
394 {
395 if (local) {
396 if (__rxrpc_unuse_local(local)) {
397 rxrpc_get_local(local);
398 rxrpc_queue_local(local);
399 }
400 }
401 }
402
403 /*
404 * Destroy a local endpoint's socket and then hand the record to RCU to dispose
405 * of.
406 *
407 * Closing the socket cannot be done from bottom half context or RCU callback
408 * context because it might sleep.
409 */
rxrpc_local_destroyer(struct rxrpc_local * local)410 static void rxrpc_local_destroyer(struct rxrpc_local *local)
411 {
412 struct socket *socket = local->socket;
413 struct rxrpc_net *rxnet = local->rxnet;
414
415 _enter("%d", local->debug_id);
416
417 local->dead = true;
418
419 mutex_lock(&rxnet->local_mutex);
420 list_del_init(&local->link);
421 mutex_unlock(&rxnet->local_mutex);
422
423 rxrpc_clean_up_local_conns(local);
424 rxrpc_service_connection_reaper(&rxnet->service_conn_reaper);
425 ASSERT(!local->service);
426
427 if (socket) {
428 local->socket = NULL;
429 kernel_sock_shutdown(socket, SHUT_RDWR);
430 socket->sk->sk_user_data = NULL;
431 sock_release(socket);
432 }
433
434 /* At this point, there should be no more packets coming in to the
435 * local endpoint.
436 */
437 rxrpc_purge_queue(&local->reject_queue);
438 rxrpc_purge_queue(&local->event_queue);
439 }
440
441 /*
442 * Process events on an endpoint. The work item carries a ref which
443 * we must release.
444 */
rxrpc_local_processor(struct work_struct * work)445 static void rxrpc_local_processor(struct work_struct *work)
446 {
447 struct rxrpc_local *local =
448 container_of(work, struct rxrpc_local, processor);
449 bool again;
450
451 if (local->dead)
452 return;
453
454 trace_rxrpc_local(local->debug_id, rxrpc_local_processing,
455 atomic_read(&local->usage), NULL);
456
457 do {
458 again = false;
459 if (!__rxrpc_use_local(local)) {
460 rxrpc_local_destroyer(local);
461 break;
462 }
463
464 if (!skb_queue_empty(&local->reject_queue)) {
465 rxrpc_reject_packets(local);
466 again = true;
467 }
468
469 if (!skb_queue_empty(&local->event_queue)) {
470 rxrpc_process_local_events(local);
471 again = true;
472 }
473
474 __rxrpc_unuse_local(local);
475 } while (again);
476
477 rxrpc_put_local(local);
478 }
479
480 /*
481 * Destroy a local endpoint after the RCU grace period expires.
482 */
rxrpc_local_rcu(struct rcu_head * rcu)483 static void rxrpc_local_rcu(struct rcu_head *rcu)
484 {
485 struct rxrpc_local *local = container_of(rcu, struct rxrpc_local, rcu);
486
487 _enter("%d", local->debug_id);
488
489 ASSERT(!work_pending(&local->processor));
490
491 _net("DESTROY LOCAL %d", local->debug_id);
492 kfree(local);
493 _leave("");
494 }
495
496 /*
497 * Verify the local endpoint list is empty by this point.
498 */
rxrpc_destroy_all_locals(struct rxrpc_net * rxnet)499 void rxrpc_destroy_all_locals(struct rxrpc_net *rxnet)
500 {
501 struct rxrpc_local *local;
502
503 _enter("");
504
505 flush_workqueue(rxrpc_workqueue);
506
507 if (!list_empty(&rxnet->local_endpoints)) {
508 mutex_lock(&rxnet->local_mutex);
509 list_for_each_entry(local, &rxnet->local_endpoints, link) {
510 pr_err("AF_RXRPC: Leaked local %p {%d}\n",
511 local, atomic_read(&local->usage));
512 }
513 mutex_unlock(&rxnet->local_mutex);
514 BUG();
515 }
516 }
517