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rxrpc: Fix exclusive connection handling
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17926a79
DH
1/* incoming call handling
2 *
3 * Copyright (C) 2007 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
9b6d5398
JP
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
17926a79
DH
14#include <linux/module.h>
15#include <linux/net.h>
16#include <linux/skbuff.h>
17#include <linux/errqueue.h>
18#include <linux/udp.h>
19#include <linux/in.h>
20#include <linux/in6.h>
21#include <linux/icmp.h>
5a0e3ad6 22#include <linux/gfp.h>
17926a79
DH
23#include <net/sock.h>
24#include <net/af_rxrpc.h>
25#include <net/ip.h>
26#include "ar-internal.h"
27
28/*
29 * generate a connection-level abort
30 */
31static int rxrpc_busy(struct rxrpc_local *local, struct sockaddr_rxrpc *srx,
0d12f8a4 32 struct rxrpc_wire_header *whdr)
17926a79
DH
33{
34 struct msghdr msg;
35 struct kvec iov[1];
36 size_t len;
37 int ret;
38
39 _enter("%d,,", local->debug_id);
40
0d12f8a4
DH
41 whdr->type = RXRPC_PACKET_TYPE_BUSY;
42 whdr->serial = htonl(1);
43
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DH
44 msg.msg_name = &srx->transport.sin;
45 msg.msg_namelen = sizeof(srx->transport.sin);
46 msg.msg_control = NULL;
47 msg.msg_controllen = 0;
48 msg.msg_flags = 0;
49
0d12f8a4
DH
50 iov[0].iov_base = whdr;
51 iov[0].iov_len = sizeof(*whdr);
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DH
52
53 len = iov[0].iov_len;
54
0d12f8a4 55 _proto("Tx BUSY %%1");
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DH
56
57 ret = kernel_sendmsg(local->socket, &msg, iov, 1, len);
58 if (ret < 0) {
59 _leave(" = -EAGAIN [sendmsg failed: %d]", ret);
60 return -EAGAIN;
61 }
62
63 _leave(" = 0");
64 return 0;
65}
66
67/*
68 * accept an incoming call that needs peer, transport and/or connection setting
69 * up
70 */
71static int rxrpc_accept_incoming_call(struct rxrpc_local *local,
72 struct rxrpc_sock *rx,
73 struct sk_buff *skb,
74 struct sockaddr_rxrpc *srx)
75{
76 struct rxrpc_connection *conn;
77 struct rxrpc_transport *trans;
78 struct rxrpc_skb_priv *sp, *nsp;
79 struct rxrpc_peer *peer;
80 struct rxrpc_call *call;
81 struct sk_buff *notification;
82 int ret;
83
84 _enter("");
85
86 sp = rxrpc_skb(skb);
87
88 /* get a notification message to send to the server app */
89 notification = alloc_skb(0, GFP_NOFS);
c3824d21
TH
90 if (!notification) {
91 _debug("no memory");
92 ret = -ENOMEM;
93 goto error_nofree;
94 }
17926a79
DH
95 rxrpc_new_skb(notification);
96 notification->mark = RXRPC_SKB_MARK_NEW_CALL;
97
be6e6707 98 peer = rxrpc_lookup_peer(local, srx, GFP_NOIO);
0e4699e4 99 if (!peer) {
17926a79
DH
100 _debug("no peer");
101 ret = -EBUSY;
102 goto error;
103 }
104
105 trans = rxrpc_get_transport(local, peer, GFP_NOIO);
106 rxrpc_put_peer(peer);
34093d05 107 if (IS_ERR(trans)) {
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DH
108 _debug("no trans");
109 ret = -EBUSY;
110 goto error;
111 }
112
843099ca 113 conn = rxrpc_incoming_connection(trans, &sp->hdr);
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DH
114 rxrpc_put_transport(trans);
115 if (IS_ERR(conn)) {
116 _debug("no conn");
117 ret = PTR_ERR(conn);
118 goto error;
119 }
120
843099ca 121 call = rxrpc_incoming_call(rx, conn, &sp->hdr);
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DH
122 rxrpc_put_connection(conn);
123 if (IS_ERR(call)) {
124 _debug("no call");
125 ret = PTR_ERR(call);
126 goto error;
127 }
128
129 /* attach the call to the socket */
130 read_lock_bh(&local->services_lock);
131 if (rx->sk.sk_state == RXRPC_CLOSE)
132 goto invalid_service;
133
134 write_lock(&rx->call_lock);
135 if (!test_and_set_bit(RXRPC_CALL_INIT_ACCEPT, &call->flags)) {
136 rxrpc_get_call(call);
137
138 spin_lock(&call->conn->state_lock);
139 if (sp->hdr.securityIndex > 0 &&
140 call->conn->state == RXRPC_CONN_SERVER_UNSECURED) {
141 _debug("await conn sec");
142 list_add_tail(&call->accept_link, &rx->secureq);
143 call->conn->state = RXRPC_CONN_SERVER_CHALLENGING;
144 atomic_inc(&call->conn->usage);
145 set_bit(RXRPC_CONN_CHALLENGE, &call->conn->events);
651350d1 146 rxrpc_queue_conn(call->conn);
17926a79
DH
147 } else {
148 _debug("conn ready");
149 call->state = RXRPC_CALL_SERVER_ACCEPTING;
150 list_add_tail(&call->accept_link, &rx->acceptq);
151 rxrpc_get_call(call);
152 nsp = rxrpc_skb(notification);
153 nsp->call = call;
154
155 ASSERTCMP(atomic_read(&call->usage), >=, 3);
156
157 _debug("notify");
158 spin_lock(&call->lock);
159 ret = rxrpc_queue_rcv_skb(call, notification, true,
160 false);
161 spin_unlock(&call->lock);
162 notification = NULL;
163e3cb7 163 BUG_ON(ret < 0);
17926a79
DH
164 }
165 spin_unlock(&call->conn->state_lock);
166
167 _debug("queued");
168 }
169 write_unlock(&rx->call_lock);
170
171 _debug("process");
172 rxrpc_fast_process_packet(call, skb);
173
174 _debug("done");
175 read_unlock_bh(&local->services_lock);
176 rxrpc_free_skb(notification);
177 rxrpc_put_call(call);
178 _leave(" = 0");
179 return 0;
180
181invalid_service:
182 _debug("invalid");
183 read_unlock_bh(&local->services_lock);
184
185 read_lock_bh(&call->state_lock);
e721498a 186 if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
4c198ad1 187 !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events)) {
17926a79 188 rxrpc_get_call(call);
651350d1 189 rxrpc_queue_call(call);
17926a79
DH
190 }
191 read_unlock_bh(&call->state_lock);
192 rxrpc_put_call(call);
193 ret = -ECONNREFUSED;
194error:
195 rxrpc_free_skb(notification);
c3824d21 196error_nofree:
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DH
197 _leave(" = %d", ret);
198 return ret;
199}
200
201/*
202 * accept incoming calls that need peer, transport and/or connection setting up
203 * - the packets we get are all incoming client DATA packets that have seq == 1
204 */
4f95dd78 205void rxrpc_accept_incoming_calls(struct rxrpc_local *local)
17926a79 206{
17926a79
DH
207 struct rxrpc_skb_priv *sp;
208 struct sockaddr_rxrpc srx;
209 struct rxrpc_sock *rx;
0d12f8a4 210 struct rxrpc_wire_header whdr;
17926a79 211 struct sk_buff *skb;
17926a79
DH
212 int ret;
213
214 _enter("%d", local->debug_id);
215
17926a79
DH
216 skb = skb_dequeue(&local->accept_queue);
217 if (!skb) {
17926a79
DH
218 _leave("\n");
219 return;
220 }
221
222 _net("incoming call skb %p", skb);
223
224 sp = rxrpc_skb(skb);
225
0d12f8a4
DH
226 /* Set up a response packet header in case we need it */
227 whdr.epoch = htonl(sp->hdr.epoch);
228 whdr.cid = htonl(sp->hdr.cid);
229 whdr.callNumber = htonl(sp->hdr.callNumber);
230 whdr.seq = htonl(sp->hdr.seq);
231 whdr.serial = 0;
232 whdr.flags = 0;
233 whdr.type = 0;
234 whdr.userStatus = 0;
235 whdr.securityIndex = sp->hdr.securityIndex;
236 whdr._rsvd = 0;
237 whdr.serviceId = htons(sp->hdr.serviceId);
238
17926a79
DH
239 /* determine the remote address */
240 memset(&srx, 0, sizeof(srx));
241 srx.srx_family = AF_RXRPC;
242 srx.transport.family = local->srx.transport.family;
243 srx.transport_type = local->srx.transport_type;
244 switch (srx.transport.family) {
245 case AF_INET:
246 srx.transport_len = sizeof(struct sockaddr_in);
247 srx.transport.sin.sin_port = udp_hdr(skb)->source;
248 srx.transport.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
249 break;
250 default:
251 goto busy;
252 }
253
254 /* get the socket providing the service */
17926a79
DH
255 read_lock_bh(&local->services_lock);
256 list_for_each_entry(rx, &local->services, listen_link) {
0d12f8a4 257 if (rx->srx.srx_service == sp->hdr.serviceId &&
17926a79
DH
258 rx->sk.sk_state != RXRPC_CLOSE)
259 goto found_service;
260 }
261 read_unlock_bh(&local->services_lock);
262 goto invalid_service;
263
264found_service:
0d12f8a4 265 _debug("found service %hd", rx->srx.srx_service);
17926a79
DH
266 if (sk_acceptq_is_full(&rx->sk))
267 goto backlog_full;
268 sk_acceptq_added(&rx->sk);
269 sock_hold(&rx->sk);
270 read_unlock_bh(&local->services_lock);
271
272 ret = rxrpc_accept_incoming_call(local, rx, skb, &srx);
273 if (ret < 0)
274 sk_acceptq_removed(&rx->sk);
275 sock_put(&rx->sk);
276 switch (ret) {
277 case -ECONNRESET: /* old calls are ignored */
278 case -ECONNABORTED: /* aborted calls are reaborted or ignored */
279 case 0:
4f95dd78 280 return;
17926a79
DH
281 case -ECONNREFUSED:
282 goto invalid_service;
283 case -EBUSY:
284 goto busy;
285 case -EKEYREJECTED:
286 goto security_mismatch;
287 default:
288 BUG();
289 }
290
291backlog_full:
292 read_unlock_bh(&local->services_lock);
293busy:
0d12f8a4 294 rxrpc_busy(local, &srx, &whdr);
17926a79 295 rxrpc_free_skb(skb);
4f95dd78 296 return;
17926a79
DH
297
298invalid_service:
299 skb->priority = RX_INVALID_OPERATION;
300 rxrpc_reject_packet(local, skb);
4f95dd78 301 return;
17926a79
DH
302
303 /* can't change connection security type mid-flow */
304security_mismatch:
305 skb->priority = RX_PROTOCOL_ERROR;
306 rxrpc_reject_packet(local, skb);
4f95dd78 307 return;
17926a79
DH
308}
309
310/*
311 * handle acceptance of a call by userspace
312 * - assign the user call ID to the call at the front of the queue
313 */
651350d1
DH
314struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
315 unsigned long user_call_ID)
17926a79
DH
316{
317 struct rxrpc_call *call;
318 struct rb_node *parent, **pp;
319 int ret;
320
321 _enter(",%lx", user_call_ID);
322
323 ASSERT(!irqs_disabled());
324
325 write_lock(&rx->call_lock);
326
327 ret = -ENODATA;
328 if (list_empty(&rx->acceptq))
329 goto out;
330
331 /* check the user ID isn't already in use */
332 ret = -EBADSLT;
333 pp = &rx->calls.rb_node;
334 parent = NULL;
335 while (*pp) {
336 parent = *pp;
337 call = rb_entry(parent, struct rxrpc_call, sock_node);
338
339 if (user_call_ID < call->user_call_ID)
340 pp = &(*pp)->rb_left;
341 else if (user_call_ID > call->user_call_ID)
342 pp = &(*pp)->rb_right;
343 else
344 goto out;
345 }
346
347 /* dequeue the first call and check it's still valid */
348 call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
349 list_del_init(&call->accept_link);
350 sk_acceptq_removed(&rx->sk);
351
352 write_lock_bh(&call->state_lock);
353 switch (call->state) {
354 case RXRPC_CALL_SERVER_ACCEPTING:
355 call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
356 break;
357 case RXRPC_CALL_REMOTELY_ABORTED:
358 case RXRPC_CALL_LOCALLY_ABORTED:
359 ret = -ECONNABORTED;
360 goto out_release;
361 case RXRPC_CALL_NETWORK_ERROR:
362 ret = call->conn->error;
363 goto out_release;
364 case RXRPC_CALL_DEAD:
365 ret = -ETIME;
366 goto out_discard;
367 default:
368 BUG();
369 }
370
371 /* formalise the acceptance */
372 call->user_call_ID = user_call_ID;
373 rb_link_node(&call->sock_node, parent, pp);
374 rb_insert_color(&call->sock_node, &rx->calls);
375 if (test_and_set_bit(RXRPC_CALL_HAS_USERID, &call->flags))
376 BUG();
4c198ad1 377 if (test_and_set_bit(RXRPC_CALL_EV_ACCEPTED, &call->events))
17926a79 378 BUG();
651350d1 379 rxrpc_queue_call(call);
17926a79 380
651350d1 381 rxrpc_get_call(call);
17926a79
DH
382 write_unlock_bh(&call->state_lock);
383 write_unlock(&rx->call_lock);
651350d1
DH
384 _leave(" = %p{%d}", call, call->debug_id);
385 return call;
386
387 /* if the call is already dying or dead, then we leave the socket's ref
388 * on it to be released by rxrpc_dead_call_expired() as induced by
389 * rxrpc_release_call() */
390out_release:
391 _debug("release %p", call);
392 if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
4c198ad1 393 !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
651350d1
DH
394 rxrpc_queue_call(call);
395out_discard:
396 write_unlock_bh(&call->state_lock);
397 _debug("discard %p", call);
398out:
399 write_unlock(&rx->call_lock);
400 _leave(" = %d", ret);
401 return ERR_PTR(ret);
402}
403
404/*
b4f1342f 405 * Handle rejection of a call by userspace
651350d1
DH
406 * - reject the call at the front of the queue
407 */
408int rxrpc_reject_call(struct rxrpc_sock *rx)
409{
410 struct rxrpc_call *call;
411 int ret;
412
413 _enter("");
414
415 ASSERT(!irqs_disabled());
416
417 write_lock(&rx->call_lock);
418
419 ret = -ENODATA;
420 if (list_empty(&rx->acceptq))
421 goto out;
422
423 /* dequeue the first call and check it's still valid */
424 call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
425 list_del_init(&call->accept_link);
426 sk_acceptq_removed(&rx->sk);
427
428 write_lock_bh(&call->state_lock);
429 switch (call->state) {
430 case RXRPC_CALL_SERVER_ACCEPTING:
431 call->state = RXRPC_CALL_SERVER_BUSY;
4c198ad1 432 if (test_and_set_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events))
651350d1
DH
433 rxrpc_queue_call(call);
434 ret = 0;
435 goto out_release;
436 case RXRPC_CALL_REMOTELY_ABORTED:
437 case RXRPC_CALL_LOCALLY_ABORTED:
438 ret = -ECONNABORTED;
439 goto out_release;
440 case RXRPC_CALL_NETWORK_ERROR:
441 ret = call->conn->error;
442 goto out_release;
443 case RXRPC_CALL_DEAD:
444 ret = -ETIME;
445 goto out_discard;
446 default:
447 BUG();
448 }
17926a79
DH
449
450 /* if the call is already dying or dead, then we leave the socket's ref
451 * on it to be released by rxrpc_dead_call_expired() as induced by
452 * rxrpc_release_call() */
453out_release:
454 _debug("release %p", call);
455 if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
4c198ad1 456 !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
651350d1 457 rxrpc_queue_call(call);
17926a79
DH
458out_discard:
459 write_unlock_bh(&call->state_lock);
460 _debug("discard %p", call);
461out:
462 write_unlock(&rx->call_lock);
463 _leave(" = %d", ret);
464 return ret;
465}
651350d1
DH
466
467/**
468 * rxrpc_kernel_accept_call - Allow a kernel service to accept an incoming call
469 * @sock: The socket on which the impending call is waiting
470 * @user_call_ID: The tag to attach to the call
471 *
472 * Allow a kernel service to accept an incoming call, assuming the incoming
473 * call is still valid.
474 */
475struct rxrpc_call *rxrpc_kernel_accept_call(struct socket *sock,
476 unsigned long user_call_ID)
477{
478 struct rxrpc_call *call;
479
480 _enter(",%lx", user_call_ID);
481 call = rxrpc_accept_call(rxrpc_sk(sock->sk), user_call_ID);
482 _leave(" = %p", call);
483 return call;
484}
651350d1
DH
485EXPORT_SYMBOL(rxrpc_kernel_accept_call);
486
487/**
488 * rxrpc_kernel_reject_call - Allow a kernel service to reject an incoming call
489 * @sock: The socket on which the impending call is waiting
490 *
491 * Allow a kernel service to reject an incoming call with a BUSY message,
492 * assuming the incoming call is still valid.
493 */
494int rxrpc_kernel_reject_call(struct socket *sock)
495{
496 int ret;
497
498 _enter("");
499 ret = rxrpc_reject_call(rxrpc_sk(sock->sk));
500 _leave(" = %d", ret);
501 return ret;
502}
651350d1 503EXPORT_SYMBOL(rxrpc_kernel_reject_call);