1 /* incoming call handling
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
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.
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
20 #include <linux/in6.h>
21 #include <linux/icmp.h>
22 #include <linux/gfp.h>
23 #include <linux/circ_buf.h>
25 #include <net/af_rxrpc.h>
27 #include "ar-internal.h"
30 * Preallocate a single service call, connection and peer and, if possible,
31 * give them a user ID and attach the user's side of the ID to them.
33 static int rxrpc_service_prealloc_one(struct rxrpc_sock
*rx
,
34 struct rxrpc_backlog
*b
,
35 rxrpc_notify_rx_t notify_rx
,
36 rxrpc_user_attach_call_t user_attach_call
,
37 unsigned long user_call_ID
, gfp_t gfp
)
39 const void *here
= __builtin_return_address(0);
40 struct rxrpc_call
*call
;
42 unsigned int size
= RXRPC_BACKLOG_MAX
;
43 unsigned int head
, tail
, call_head
, call_tail
;
45 max
= rx
->sk
.sk_max_ack_backlog
;
46 tmp
= rx
->sk
.sk_ack_backlog
;
48 _leave(" = -ENOBUFS [full %u]", max
);
53 /* We don't need more conns and peers than we have calls, but on the
54 * other hand, we shouldn't ever use more peers than conns or conns
57 call_head
= b
->call_backlog_head
;
58 call_tail
= READ_ONCE(b
->call_backlog_tail
);
59 tmp
= CIRC_CNT(call_head
, call_tail
, size
);
61 _leave(" = -ENOBUFS [enough %u]", tmp
);
66 head
= b
->peer_backlog_head
;
67 tail
= READ_ONCE(b
->peer_backlog_tail
);
68 if (CIRC_CNT(head
, tail
, size
) < max
) {
69 struct rxrpc_peer
*peer
= rxrpc_alloc_peer(rx
->local
, gfp
);
72 b
->peer_backlog
[head
] = peer
;
73 smp_store_release(&b
->peer_backlog_head
,
74 (head
+ 1) & (size
- 1));
77 head
= b
->conn_backlog_head
;
78 tail
= READ_ONCE(b
->conn_backlog_tail
);
79 if (CIRC_CNT(head
, tail
, size
) < max
) {
80 struct rxrpc_connection
*conn
;
82 conn
= rxrpc_prealloc_service_connection(gfp
);
85 b
->conn_backlog
[head
] = conn
;
86 smp_store_release(&b
->conn_backlog_head
,
87 (head
+ 1) & (size
- 1));
89 trace_rxrpc_conn(conn
, rxrpc_conn_new_service
,
90 atomic_read(&conn
->usage
), here
);
93 /* Now it gets complicated, because calls get registered with the
94 * socket here, particularly if a user ID is preassigned by the user.
96 call
= rxrpc_alloc_call(gfp
);
99 call
->flags
|= (1 << RXRPC_CALL_IS_SERVICE
);
100 call
->state
= RXRPC_CALL_SERVER_PREALLOC
;
102 trace_rxrpc_call(call
, rxrpc_call_new_service
,
103 atomic_read(&call
->usage
),
104 here
, (const void *)user_call_ID
);
106 write_lock(&rx
->call_lock
);
107 if (user_attach_call
) {
108 struct rxrpc_call
*xcall
;
109 struct rb_node
*parent
, **pp
;
111 /* Check the user ID isn't already in use */
112 pp
= &rx
->calls
.rb_node
;
116 xcall
= rb_entry(parent
, struct rxrpc_call
, sock_node
);
117 if (user_call_ID
< call
->user_call_ID
)
118 pp
= &(*pp
)->rb_left
;
119 else if (user_call_ID
> call
->user_call_ID
)
120 pp
= &(*pp
)->rb_right
;
125 call
->user_call_ID
= user_call_ID
;
126 call
->notify_rx
= notify_rx
;
127 rxrpc_get_call(call
, rxrpc_call_got_kernel
);
128 user_attach_call(call
, user_call_ID
);
129 rxrpc_get_call(call
, rxrpc_call_got_userid
);
130 rb_link_node(&call
->sock_node
, parent
, pp
);
131 rb_insert_color(&call
->sock_node
, &rx
->calls
);
132 set_bit(RXRPC_CALL_HAS_USERID
, &call
->flags
);
135 list_add(&call
->sock_link
, &rx
->sock_calls
);
137 write_unlock(&rx
->call_lock
);
139 write_lock(&rxrpc_call_lock
);
140 list_add_tail(&call
->link
, &rxrpc_calls
);
141 write_unlock(&rxrpc_call_lock
);
143 b
->call_backlog
[call_head
] = call
;
144 smp_store_release(&b
->call_backlog_head
, (call_head
+ 1) & (size
- 1));
145 _leave(" = 0 [%d -> %lx]", call
->debug_id
, user_call_ID
);
149 write_unlock(&rx
->call_lock
);
150 rxrpc_cleanup_call(call
);
151 _leave(" = -EBADSLT");
156 * Preallocate sufficient service connections, calls and peers to cover the
157 * entire backlog of a socket. When a new call comes in, if we don't have
158 * sufficient of each available, the call gets rejected as busy or ignored.
160 * The backlog is replenished when a connection is accepted or rejected.
162 int rxrpc_service_prealloc(struct rxrpc_sock
*rx
, gfp_t gfp
)
164 struct rxrpc_backlog
*b
= rx
->backlog
;
167 b
= kzalloc(sizeof(struct rxrpc_backlog
), gfp
);
173 if (rx
->discard_new_call
)
176 while (rxrpc_service_prealloc_one(rx
, b
, NULL
, NULL
, 0, gfp
) == 0)
183 * Discard the preallocation on a service.
185 void rxrpc_discard_prealloc(struct rxrpc_sock
*rx
)
187 struct rxrpc_backlog
*b
= rx
->backlog
;
188 unsigned int size
= RXRPC_BACKLOG_MAX
, head
, tail
;
194 /* Make sure that there aren't any incoming calls in progress before we
195 * clear the preallocation buffers.
197 spin_lock_bh(&rx
->incoming_lock
);
198 spin_unlock_bh(&rx
->incoming_lock
);
200 head
= b
->peer_backlog_head
;
201 tail
= b
->peer_backlog_tail
;
202 while (CIRC_CNT(head
, tail
, size
) > 0) {
203 struct rxrpc_peer
*peer
= b
->peer_backlog
[tail
];
205 tail
= (tail
+ 1) & (size
- 1);
208 head
= b
->conn_backlog_head
;
209 tail
= b
->conn_backlog_tail
;
210 while (CIRC_CNT(head
, tail
, size
) > 0) {
211 struct rxrpc_connection
*conn
= b
->conn_backlog
[tail
];
212 write_lock(&rxrpc_connection_lock
);
213 list_del(&conn
->link
);
214 list_del(&conn
->proc_link
);
215 write_unlock(&rxrpc_connection_lock
);
217 tail
= (tail
+ 1) & (size
- 1);
220 head
= b
->call_backlog_head
;
221 tail
= b
->call_backlog_tail
;
222 while (CIRC_CNT(head
, tail
, size
) > 0) {
223 struct rxrpc_call
*call
= b
->call_backlog
[tail
];
224 if (rx
->discard_new_call
) {
225 _debug("discard %lx", call
->user_call_ID
);
226 rx
->discard_new_call(call
, call
->user_call_ID
);
227 rxrpc_put_call(call
, rxrpc_call_put_kernel
);
229 rxrpc_call_completed(call
);
230 rxrpc_release_call(rx
, call
);
231 rxrpc_put_call(call
, rxrpc_call_put
);
232 tail
= (tail
+ 1) & (size
- 1);
239 * Allocate a new incoming call from the prealloc pool, along with a connection
240 * and a peer as necessary.
242 static struct rxrpc_call
*rxrpc_alloc_incoming_call(struct rxrpc_sock
*rx
,
243 struct rxrpc_local
*local
,
244 struct rxrpc_connection
*conn
,
247 struct rxrpc_backlog
*b
= rx
->backlog
;
248 struct rxrpc_peer
*peer
, *xpeer
;
249 struct rxrpc_call
*call
;
250 unsigned short call_head
, conn_head
, peer_head
;
251 unsigned short call_tail
, conn_tail
, peer_tail
;
252 unsigned short call_count
, conn_count
;
254 /* #calls >= #conns >= #peers must hold true. */
255 call_head
= smp_load_acquire(&b
->call_backlog_head
);
256 call_tail
= b
->call_backlog_tail
;
257 call_count
= CIRC_CNT(call_head
, call_tail
, RXRPC_BACKLOG_MAX
);
258 conn_head
= smp_load_acquire(&b
->conn_backlog_head
);
259 conn_tail
= b
->conn_backlog_tail
;
260 conn_count
= CIRC_CNT(conn_head
, conn_tail
, RXRPC_BACKLOG_MAX
);
261 ASSERTCMP(conn_count
, >=, call_count
);
262 peer_head
= smp_load_acquire(&b
->peer_backlog_head
);
263 peer_tail
= b
->peer_backlog_tail
;
264 ASSERTCMP(CIRC_CNT(peer_head
, peer_tail
, RXRPC_BACKLOG_MAX
), >=,
271 /* No connection. We're going to need a peer to start off
272 * with. If one doesn't yet exist, use a spare from the
273 * preallocation set. We dump the address into the spare in
274 * anticipation - and to save on stack space.
276 xpeer
= b
->peer_backlog
[peer_tail
];
277 if (rxrpc_extract_addr_from_skb(&xpeer
->srx
, skb
) < 0)
280 peer
= rxrpc_lookup_incoming_peer(local
, xpeer
);
282 b
->peer_backlog
[peer_tail
] = NULL
;
283 smp_store_release(&b
->peer_backlog_tail
,
285 (RXRPC_BACKLOG_MAX
- 1));
288 /* Now allocate and set up the connection */
289 conn
= b
->conn_backlog
[conn_tail
];
290 b
->conn_backlog
[conn_tail
] = NULL
;
291 smp_store_release(&b
->conn_backlog_tail
,
292 (conn_tail
+ 1) & (RXRPC_BACKLOG_MAX
- 1));
293 rxrpc_get_local(local
);
294 conn
->params
.local
= local
;
295 conn
->params
.peer
= peer
;
296 rxrpc_see_connection(conn
);
297 rxrpc_new_incoming_connection(conn
, skb
);
299 rxrpc_get_connection(conn
);
302 /* And now we can allocate and set up a new call */
303 call
= b
->call_backlog
[call_tail
];
304 b
->call_backlog
[call_tail
] = NULL
;
305 smp_store_release(&b
->call_backlog_tail
,
306 (call_tail
+ 1) & (RXRPC_BACKLOG_MAX
- 1));
308 rxrpc_see_call(call
);
310 call
->peer
= rxrpc_get_peer(conn
->params
.peer
);
315 * Set up a new incoming call. Called in BH context with the RCU read lock
318 * If this is for a kernel service, when we allocate the call, it will have
319 * three refs on it: (1) the kernel service, (2) the user_call_ID tree, (3) the
320 * retainer ref obtained from the backlog buffer. Prealloc calls for userspace
321 * services only have the ref from the backlog buffer. We want to pass this
322 * ref to non-BH context to dispose of.
324 * If we want to report an error, we mark the skb with the packet type and
325 * abort code and return NULL.
327 struct rxrpc_call
*rxrpc_new_incoming_call(struct rxrpc_local
*local
,
328 struct rxrpc_connection
*conn
,
331 struct rxrpc_skb_priv
*sp
= rxrpc_skb(skb
);
332 struct rxrpc_sock
*rx
;
333 struct rxrpc_call
*call
;
334 u16 service_id
= sp
->hdr
.serviceId
;
338 /* Get the socket providing the service */
339 rx
= rcu_dereference(local
->service
);
340 if (rx
&& service_id
== rx
->srx
.srx_service
)
343 trace_rxrpc_abort("INV", sp
->hdr
.cid
, sp
->hdr
.callNumber
, sp
->hdr
.seq
,
344 RX_INVALID_OPERATION
, EOPNOTSUPP
);
345 skb
->mark
= RXRPC_SKB_MARK_LOCAL_ABORT
;
346 skb
->priority
= RX_INVALID_OPERATION
;
347 _leave(" = NULL [service]");
351 spin_lock(&rx
->incoming_lock
);
352 if (rx
->sk
.sk_state
== RXRPC_CLOSE
) {
353 trace_rxrpc_abort("CLS", sp
->hdr
.cid
, sp
->hdr
.callNumber
,
354 sp
->hdr
.seq
, RX_INVALID_OPERATION
, ESHUTDOWN
);
355 skb
->mark
= RXRPC_SKB_MARK_LOCAL_ABORT
;
356 skb
->priority
= RX_INVALID_OPERATION
;
357 _leave(" = NULL [close]");
362 call
= rxrpc_alloc_incoming_call(rx
, local
, conn
, skb
);
364 skb
->mark
= RXRPC_SKB_MARK_BUSY
;
365 _leave(" = NULL [busy]");
370 trace_rxrpc_receive(call
, rxrpc_receive_incoming
,
371 sp
->hdr
.serial
, sp
->hdr
.seq
);
373 /* Make the call live. */
374 rxrpc_incoming_call(rx
, call
, skb
);
377 if (rx
->notify_new_call
)
378 rx
->notify_new_call(&rx
->sk
, call
, call
->user_call_ID
);
380 sk_acceptq_added(&rx
->sk
);
382 spin_lock(&conn
->state_lock
);
383 switch (conn
->state
) {
384 case RXRPC_CONN_SERVICE_UNSECURED
:
385 conn
->state
= RXRPC_CONN_SERVICE_CHALLENGING
;
386 set_bit(RXRPC_CONN_EV_CHALLENGE
, &call
->conn
->events
);
387 rxrpc_queue_conn(call
->conn
);
390 case RXRPC_CONN_SERVICE
:
391 write_lock(&call
->state_lock
);
392 if (rx
->discard_new_call
)
393 call
->state
= RXRPC_CALL_SERVER_RECV_REQUEST
;
395 call
->state
= RXRPC_CALL_SERVER_ACCEPTING
;
396 write_unlock(&call
->state_lock
);
399 case RXRPC_CONN_REMOTELY_ABORTED
:
400 rxrpc_set_call_completion(call
, RXRPC_CALL_REMOTELY_ABORTED
,
401 conn
->remote_abort
, ECONNABORTED
);
403 case RXRPC_CONN_LOCALLY_ABORTED
:
404 rxrpc_abort_call("CON", call
, sp
->hdr
.seq
,
405 conn
->local_abort
, ECONNABORTED
);
410 spin_unlock(&conn
->state_lock
);
412 if (call
->state
== RXRPC_CALL_SERVER_ACCEPTING
)
413 rxrpc_notify_socket(call
);
415 /* We have to discard the prealloc queue's ref here and rely on a
416 * combination of the RCU read lock and refs held either by the socket
417 * (recvmsg queue, to-be-accepted queue or user ID tree) or the kernel
418 * service to prevent the call from being deallocated too early.
420 rxrpc_put_call(call
, rxrpc_call_put
);
422 _leave(" = %p{%d}", call
, call
->debug_id
);
424 spin_unlock(&rx
->incoming_lock
);
429 * handle acceptance of a call by userspace
430 * - assign the user call ID to the call at the front of the queue
432 struct rxrpc_call
*rxrpc_accept_call(struct rxrpc_sock
*rx
,
433 unsigned long user_call_ID
,
434 rxrpc_notify_rx_t notify_rx
)
436 struct rxrpc_call
*call
;
437 struct rb_node
*parent
, **pp
;
440 _enter(",%lx", user_call_ID
);
442 ASSERT(!irqs_disabled());
444 write_lock(&rx
->call_lock
);
446 if (list_empty(&rx
->to_be_accepted
)) {
447 write_unlock(&rx
->call_lock
);
448 kleave(" = -ENODATA [empty]");
449 return ERR_PTR(-ENODATA
);
452 /* check the user ID isn't already in use */
453 pp
= &rx
->calls
.rb_node
;
457 call
= rb_entry(parent
, struct rxrpc_call
, sock_node
);
459 if (user_call_ID
< call
->user_call_ID
)
460 pp
= &(*pp
)->rb_left
;
461 else if (user_call_ID
> call
->user_call_ID
)
462 pp
= &(*pp
)->rb_right
;
467 /* Dequeue the first call and check it's still valid. We gain
468 * responsibility for the queue's reference.
470 call
= list_entry(rx
->to_be_accepted
.next
,
471 struct rxrpc_call
, accept_link
);
472 list_del_init(&call
->accept_link
);
473 sk_acceptq_removed(&rx
->sk
);
474 rxrpc_see_call(call
);
476 write_lock_bh(&call
->state_lock
);
477 switch (call
->state
) {
478 case RXRPC_CALL_SERVER_ACCEPTING
:
479 call
->state
= RXRPC_CALL_SERVER_RECV_REQUEST
;
481 case RXRPC_CALL_COMPLETE
:
488 /* formalise the acceptance */
489 call
->notify_rx
= notify_rx
;
490 call
->user_call_ID
= user_call_ID
;
491 rxrpc_get_call(call
, rxrpc_call_got_userid
);
492 rb_link_node(&call
->sock_node
, parent
, pp
);
493 rb_insert_color(&call
->sock_node
, &rx
->calls
);
494 if (test_and_set_bit(RXRPC_CALL_HAS_USERID
, &call
->flags
))
497 write_unlock_bh(&call
->state_lock
);
498 write_unlock(&rx
->call_lock
);
499 rxrpc_notify_socket(call
);
500 rxrpc_service_prealloc(rx
, GFP_KERNEL
);
501 _leave(" = %p{%d}", call
, call
->debug_id
);
505 _debug("release %p", call
);
506 write_unlock_bh(&call
->state_lock
);
507 write_unlock(&rx
->call_lock
);
508 rxrpc_release_call(rx
, call
);
509 rxrpc_put_call(call
, rxrpc_call_put
);
514 write_unlock(&rx
->call_lock
);
516 rxrpc_service_prealloc(rx
, GFP_KERNEL
);
517 _leave(" = %d", ret
);
522 * Handle rejection of a call by userspace
523 * - reject the call at the front of the queue
525 int rxrpc_reject_call(struct rxrpc_sock
*rx
)
527 struct rxrpc_call
*call
;
533 ASSERT(!irqs_disabled());
535 write_lock(&rx
->call_lock
);
537 if (list_empty(&rx
->to_be_accepted
)) {
538 write_unlock(&rx
->call_lock
);
542 /* Dequeue the first call and check it's still valid. We gain
543 * responsibility for the queue's reference.
545 call
= list_entry(rx
->to_be_accepted
.next
,
546 struct rxrpc_call
, accept_link
);
547 list_del_init(&call
->accept_link
);
548 sk_acceptq_removed(&rx
->sk
);
549 rxrpc_see_call(call
);
551 write_lock_bh(&call
->state_lock
);
552 switch (call
->state
) {
553 case RXRPC_CALL_SERVER_ACCEPTING
:
554 __rxrpc_abort_call("REJ", call
, 1, RX_USER_ABORT
, ECONNABORTED
);
557 case RXRPC_CALL_COMPLETE
:
565 write_unlock_bh(&call
->state_lock
);
566 write_unlock(&rx
->call_lock
);
568 rxrpc_send_abort_packet(call
);
569 rxrpc_release_call(rx
, call
);
570 rxrpc_put_call(call
, rxrpc_call_put
);
572 rxrpc_service_prealloc(rx
, GFP_KERNEL
);
573 _leave(" = %d", ret
);
578 * rxrpc_kernel_charge_accept - Charge up socket with preallocated calls
579 * @sock: The socket on which to preallocate
580 * @notify_rx: Event notification function for the call
581 * @user_attach_call: Func to attach call to user_call_ID
582 * @user_call_ID: The tag to attach to the preallocated call
583 * @gfp: The allocation conditions.
585 * Charge up the socket with preallocated calls, each with a user ID. A
586 * function should be provided to effect the attachment from the user's side.
587 * The user is given a ref to hold on the call.
589 * Note that the call may be come connected before this function returns.
591 int rxrpc_kernel_charge_accept(struct socket
*sock
,
592 rxrpc_notify_rx_t notify_rx
,
593 rxrpc_user_attach_call_t user_attach_call
,
594 unsigned long user_call_ID
, gfp_t gfp
)
596 struct rxrpc_sock
*rx
= rxrpc_sk(sock
->sk
);
597 struct rxrpc_backlog
*b
= rx
->backlog
;
599 if (sock
->sk
->sk_state
== RXRPC_CLOSE
)
602 return rxrpc_service_prealloc_one(rx
, b
, notify_rx
,
603 user_attach_call
, user_call_ID
,
606 EXPORT_SYMBOL(rxrpc_kernel_charge_accept
);