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;
41 struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
43 unsigned int size = RXRPC_BACKLOG_MAX;
44 unsigned int head, tail, call_head, call_tail;
46 max = rx->sk.sk_max_ack_backlog;
47 tmp = rx->sk.sk_ack_backlog;
49 _leave(" = -ENOBUFS [full %u]", max);
54 /* We don't need more conns and peers than we have calls, but on the
55 * other hand, we shouldn't ever use more peers than conns or conns
58 call_head = b->call_backlog_head;
59 call_tail = READ_ONCE(b->call_backlog_tail);
60 tmp = CIRC_CNT(call_head, call_tail, size);
62 _leave(" = -ENOBUFS [enough %u]", tmp);
67 head = b->peer_backlog_head;
68 tail = READ_ONCE(b->peer_backlog_tail);
69 if (CIRC_CNT(head, tail, size) < max) {
70 struct rxrpc_peer *peer = rxrpc_alloc_peer(rx->local, gfp);
73 b->peer_backlog[head] = peer;
74 smp_store_release(&b->peer_backlog_head,
75 (head + 1) & (size - 1));
78 head = b->conn_backlog_head;
79 tail = READ_ONCE(b->conn_backlog_tail);
80 if (CIRC_CNT(head, tail, size) < max) {
81 struct rxrpc_connection *conn;
83 conn = rxrpc_prealloc_service_connection(rxnet, gfp);
86 b->conn_backlog[head] = conn;
87 smp_store_release(&b->conn_backlog_head,
88 (head + 1) & (size - 1));
90 trace_rxrpc_conn(conn, rxrpc_conn_new_service,
91 atomic_read(&conn->usage), here);
94 /* Now it gets complicated, because calls get registered with the
95 * socket here, particularly if a user ID is preassigned by the user.
97 call = rxrpc_alloc_call(gfp);
100 call->flags |= (1 << RXRPC_CALL_IS_SERVICE);
101 call->state = RXRPC_CALL_SERVER_PREALLOC;
103 trace_rxrpc_call(call, rxrpc_call_new_service,
104 atomic_read(&call->usage),
105 here, (const void *)user_call_ID);
107 write_lock(&rx->call_lock);
108 if (user_attach_call) {
109 struct rxrpc_call *xcall;
110 struct rb_node *parent, **pp;
112 /* Check the user ID isn't already in use */
113 pp = &rx->calls.rb_node;
117 xcall = rb_entry(parent, struct rxrpc_call, sock_node);
118 if (user_call_ID < call->user_call_ID)
119 pp = &(*pp)->rb_left;
120 else if (user_call_ID > call->user_call_ID)
121 pp = &(*pp)->rb_right;
126 call->user_call_ID = user_call_ID;
127 call->notify_rx = notify_rx;
128 rxrpc_get_call(call, rxrpc_call_got_kernel);
129 user_attach_call(call, user_call_ID);
130 rxrpc_get_call(call, rxrpc_call_got_userid);
131 rb_link_node(&call->sock_node, parent, pp);
132 rb_insert_color(&call->sock_node, &rx->calls);
133 set_bit(RXRPC_CALL_HAS_USERID, &call->flags);
136 list_add(&call->sock_link, &rx->sock_calls);
138 write_unlock(&rx->call_lock);
140 write_lock(&rxnet->call_lock);
141 list_add_tail(&call->link, &rxnet->calls);
142 write_unlock(&rxnet->call_lock);
144 b->call_backlog[call_head] = call;
145 smp_store_release(&b->call_backlog_head, (call_head + 1) & (size - 1));
146 _leave(" = 0 [%d -> %lx]", call->debug_id, user_call_ID);
150 write_unlock(&rx->call_lock);
151 rxrpc_cleanup_call(call);
152 _leave(" = -EBADSLT");
157 * Preallocate sufficient service connections, calls and peers to cover the
158 * entire backlog of a socket. When a new call comes in, if we don't have
159 * sufficient of each available, the call gets rejected as busy or ignored.
161 * The backlog is replenished when a connection is accepted or rejected.
163 int rxrpc_service_prealloc(struct rxrpc_sock *rx, gfp_t gfp)
165 struct rxrpc_backlog *b = rx->backlog;
168 b = kzalloc(sizeof(struct rxrpc_backlog), gfp);
174 if (rx->discard_new_call)
177 while (rxrpc_service_prealloc_one(rx, b, NULL, NULL, 0, gfp) == 0)
184 * Discard the preallocation on a service.
186 void rxrpc_discard_prealloc(struct rxrpc_sock *rx)
188 struct rxrpc_backlog *b = rx->backlog;
189 struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
190 unsigned int size = RXRPC_BACKLOG_MAX, head, tail;
196 /* Make sure that there aren't any incoming calls in progress before we
197 * clear the preallocation buffers.
199 spin_lock_bh(&rx->incoming_lock);
200 spin_unlock_bh(&rx->incoming_lock);
202 head = b->peer_backlog_head;
203 tail = b->peer_backlog_tail;
204 while (CIRC_CNT(head, tail, size) > 0) {
205 struct rxrpc_peer *peer = b->peer_backlog[tail];
207 tail = (tail + 1) & (size - 1);
210 head = b->conn_backlog_head;
211 tail = b->conn_backlog_tail;
212 while (CIRC_CNT(head, tail, size) > 0) {
213 struct rxrpc_connection *conn = b->conn_backlog[tail];
214 write_lock(&rxnet->conn_lock);
215 list_del(&conn->link);
216 list_del(&conn->proc_link);
217 write_unlock(&rxnet->conn_lock);
219 tail = (tail + 1) & (size - 1);
222 head = b->call_backlog_head;
223 tail = b->call_backlog_tail;
224 while (CIRC_CNT(head, tail, size) > 0) {
225 struct rxrpc_call *call = b->call_backlog[tail];
226 if (rx->discard_new_call) {
227 _debug("discard %lx", call->user_call_ID);
228 rx->discard_new_call(call, call->user_call_ID);
229 rxrpc_put_call(call, rxrpc_call_put_kernel);
231 rxrpc_call_completed(call);
232 rxrpc_release_call(rx, call);
233 rxrpc_put_call(call, rxrpc_call_put);
234 tail = (tail + 1) & (size - 1);
241 * Allocate a new incoming call from the prealloc pool, along with a connection
242 * and a peer as necessary.
244 static struct rxrpc_call *rxrpc_alloc_incoming_call(struct rxrpc_sock *rx,
245 struct rxrpc_local *local,
246 struct rxrpc_connection *conn,
249 struct rxrpc_backlog *b = rx->backlog;
250 struct rxrpc_peer *peer, *xpeer;
251 struct rxrpc_call *call;
252 unsigned short call_head, conn_head, peer_head;
253 unsigned short call_tail, conn_tail, peer_tail;
254 unsigned short call_count, conn_count;
256 /* #calls >= #conns >= #peers must hold true. */
257 call_head = smp_load_acquire(&b->call_backlog_head);
258 call_tail = b->call_backlog_tail;
259 call_count = CIRC_CNT(call_head, call_tail, RXRPC_BACKLOG_MAX);
260 conn_head = smp_load_acquire(&b->conn_backlog_head);
261 conn_tail = b->conn_backlog_tail;
262 conn_count = CIRC_CNT(conn_head, conn_tail, RXRPC_BACKLOG_MAX);
263 ASSERTCMP(conn_count, >=, call_count);
264 peer_head = smp_load_acquire(&b->peer_backlog_head);
265 peer_tail = b->peer_backlog_tail;
266 ASSERTCMP(CIRC_CNT(peer_head, peer_tail, RXRPC_BACKLOG_MAX), >=,
273 /* No connection. We're going to need a peer to start off
274 * with. If one doesn't yet exist, use a spare from the
275 * preallocation set. We dump the address into the spare in
276 * anticipation - and to save on stack space.
278 xpeer = b->peer_backlog[peer_tail];
279 if (rxrpc_extract_addr_from_skb(&xpeer->srx, skb) < 0)
282 peer = rxrpc_lookup_incoming_peer(local, xpeer);
284 b->peer_backlog[peer_tail] = NULL;
285 smp_store_release(&b->peer_backlog_tail,
287 (RXRPC_BACKLOG_MAX - 1));
290 /* Now allocate and set up the connection */
291 conn = b->conn_backlog[conn_tail];
292 b->conn_backlog[conn_tail] = NULL;
293 smp_store_release(&b->conn_backlog_tail,
294 (conn_tail + 1) & (RXRPC_BACKLOG_MAX - 1));
295 rxrpc_get_local(local);
296 conn->params.local = local;
297 conn->params.peer = peer;
298 rxrpc_see_connection(conn);
299 rxrpc_new_incoming_connection(rx, conn, skb);
301 rxrpc_get_connection(conn);
304 /* And now we can allocate and set up a new call */
305 call = b->call_backlog[call_tail];
306 b->call_backlog[call_tail] = NULL;
307 smp_store_release(&b->call_backlog_tail,
308 (call_tail + 1) & (RXRPC_BACKLOG_MAX - 1));
310 rxrpc_see_call(call);
312 call->peer = rxrpc_get_peer(conn->params.peer);
313 call->cong_cwnd = call->peer->cong_cwnd;
318 * Set up a new incoming call. Called in BH context with the RCU read lock
321 * If this is for a kernel service, when we allocate the call, it will have
322 * three refs on it: (1) the kernel service, (2) the user_call_ID tree, (3) the
323 * retainer ref obtained from the backlog buffer. Prealloc calls for userspace
324 * services only have the ref from the backlog buffer. We want to pass this
325 * ref to non-BH context to dispose of.
327 * If we want to report an error, we mark the skb with the packet type and
328 * abort code and return NULL.
330 * The call is returned with the user access mutex held.
332 struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *local,
333 struct rxrpc_connection *conn,
336 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
337 struct rxrpc_sock *rx;
338 struct rxrpc_call *call;
339 u16 service_id = sp->hdr.serviceId;
343 /* Get the socket providing the service */
344 rx = rcu_dereference(local->service);
345 if (rx && (service_id == rx->srx.srx_service ||
346 service_id == rx->second_service))
349 trace_rxrpc_abort("INV", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
350 RX_INVALID_OPERATION, EOPNOTSUPP);
351 skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
352 skb->priority = RX_INVALID_OPERATION;
353 _leave(" = NULL [service]");
357 spin_lock(&rx->incoming_lock);
358 if (rx->sk.sk_state == RXRPC_SERVER_LISTEN_DISABLED ||
359 rx->sk.sk_state == RXRPC_CLOSE) {
360 trace_rxrpc_abort("CLS", sp->hdr.cid, sp->hdr.callNumber,
361 sp->hdr.seq, RX_INVALID_OPERATION, ESHUTDOWN);
362 skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
363 skb->priority = RX_INVALID_OPERATION;
364 _leave(" = NULL [close]");
369 call = rxrpc_alloc_incoming_call(rx, local, conn, skb);
371 skb->mark = RXRPC_SKB_MARK_BUSY;
372 _leave(" = NULL [busy]");
377 trace_rxrpc_receive(call, rxrpc_receive_incoming,
378 sp->hdr.serial, sp->hdr.seq);
380 /* Lock the call to prevent rxrpc_kernel_send/recv_data() and
381 * sendmsg()/recvmsg() inconveniently stealing the mutex once the
382 * notification is generated.
384 * The BUG should never happen because the kernel should be well
385 * behaved enough not to access the call before the first notification
386 * event and userspace is prevented from doing so until the state is
389 if (!mutex_trylock(&call->user_mutex))
392 /* Make the call live. */
393 rxrpc_incoming_call(rx, call, skb);
396 if (rx->notify_new_call)
397 rx->notify_new_call(&rx->sk, call, call->user_call_ID);
399 sk_acceptq_added(&rx->sk);
401 spin_lock(&conn->state_lock);
402 switch (conn->state) {
403 case RXRPC_CONN_SERVICE_UNSECURED:
404 conn->state = RXRPC_CONN_SERVICE_CHALLENGING;
405 set_bit(RXRPC_CONN_EV_CHALLENGE, &call->conn->events);
406 rxrpc_queue_conn(call->conn);
409 case RXRPC_CONN_SERVICE:
410 write_lock(&call->state_lock);
411 if (rx->discard_new_call)
412 call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
414 call->state = RXRPC_CALL_SERVER_ACCEPTING;
415 write_unlock(&call->state_lock);
418 case RXRPC_CONN_REMOTELY_ABORTED:
419 rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
420 conn->remote_abort, -ECONNABORTED);
422 case RXRPC_CONN_LOCALLY_ABORTED:
423 rxrpc_abort_call("CON", call, sp->hdr.seq,
424 conn->local_abort, -ECONNABORTED);
429 spin_unlock(&conn->state_lock);
431 if (call->state == RXRPC_CALL_SERVER_ACCEPTING)
432 rxrpc_notify_socket(call);
434 /* We have to discard the prealloc queue's ref here and rely on a
435 * combination of the RCU read lock and refs held either by the socket
436 * (recvmsg queue, to-be-accepted queue or user ID tree) or the kernel
437 * service to prevent the call from being deallocated too early.
439 rxrpc_put_call(call, rxrpc_call_put);
441 _leave(" = %p{%d}", call, call->debug_id);
443 spin_unlock(&rx->incoming_lock);
448 * handle acceptance of a call by userspace
449 * - assign the user call ID to the call at the front of the queue
450 * - called with the socket locked.
452 struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
453 unsigned long user_call_ID,
454 rxrpc_notify_rx_t notify_rx)
455 __releases(&rx->sk.sk_lock.slock)
457 struct rxrpc_call *call;
458 struct rb_node *parent, **pp;
461 _enter(",%lx", user_call_ID);
463 ASSERT(!irqs_disabled());
465 write_lock(&rx->call_lock);
467 if (list_empty(&rx->to_be_accepted)) {
468 write_unlock(&rx->call_lock);
469 release_sock(&rx->sk);
470 kleave(" = -ENODATA [empty]");
471 return ERR_PTR(-ENODATA);
474 /* check the user ID isn't already in use */
475 pp = &rx->calls.rb_node;
479 call = rb_entry(parent, struct rxrpc_call, sock_node);
481 if (user_call_ID < call->user_call_ID)
482 pp = &(*pp)->rb_left;
483 else if (user_call_ID > call->user_call_ID)
484 pp = &(*pp)->rb_right;
489 /* Dequeue the first call and check it's still valid. We gain
490 * responsibility for the queue's reference.
492 call = list_entry(rx->to_be_accepted.next,
493 struct rxrpc_call, accept_link);
494 write_unlock(&rx->call_lock);
496 /* We need to gain the mutex from the interrupt handler without
497 * upsetting lockdep, so we have to release it there and take it here.
498 * We are, however, still holding the socket lock, so other accepts
499 * must wait for us and no one can add the user ID behind our backs.
501 if (mutex_lock_interruptible(&call->user_mutex) < 0) {
502 release_sock(&rx->sk);
503 kleave(" = -ERESTARTSYS");
504 return ERR_PTR(-ERESTARTSYS);
507 write_lock(&rx->call_lock);
508 list_del_init(&call->accept_link);
509 sk_acceptq_removed(&rx->sk);
510 rxrpc_see_call(call);
512 /* Find the user ID insertion point. */
513 pp = &rx->calls.rb_node;
517 call = rb_entry(parent, struct rxrpc_call, sock_node);
519 if (user_call_ID < call->user_call_ID)
520 pp = &(*pp)->rb_left;
521 else if (user_call_ID > call->user_call_ID)
522 pp = &(*pp)->rb_right;
527 write_lock_bh(&call->state_lock);
528 switch (call->state) {
529 case RXRPC_CALL_SERVER_ACCEPTING:
530 call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
532 case RXRPC_CALL_COMPLETE:
539 /* formalise the acceptance */
540 call->notify_rx = notify_rx;
541 call->user_call_ID = user_call_ID;
542 rxrpc_get_call(call, rxrpc_call_got_userid);
543 rb_link_node(&call->sock_node, parent, pp);
544 rb_insert_color(&call->sock_node, &rx->calls);
545 if (test_and_set_bit(RXRPC_CALL_HAS_USERID, &call->flags))
548 write_unlock_bh(&call->state_lock);
549 write_unlock(&rx->call_lock);
550 rxrpc_notify_socket(call);
551 rxrpc_service_prealloc(rx, GFP_KERNEL);
552 release_sock(&rx->sk);
553 _leave(" = %p{%d}", call, call->debug_id);
557 _debug("release %p", call);
558 write_unlock_bh(&call->state_lock);
559 write_unlock(&rx->call_lock);
560 rxrpc_release_call(rx, call);
561 rxrpc_put_call(call, rxrpc_call_put);
566 write_unlock(&rx->call_lock);
568 rxrpc_service_prealloc(rx, GFP_KERNEL);
569 release_sock(&rx->sk);
570 _leave(" = %d", ret);
575 * Handle rejection of a call by userspace
576 * - reject the call at the front of the queue
578 int rxrpc_reject_call(struct rxrpc_sock *rx)
580 struct rxrpc_call *call;
586 ASSERT(!irqs_disabled());
588 write_lock(&rx->call_lock);
590 if (list_empty(&rx->to_be_accepted)) {
591 write_unlock(&rx->call_lock);
595 /* Dequeue the first call and check it's still valid. We gain
596 * responsibility for the queue's reference.
598 call = list_entry(rx->to_be_accepted.next,
599 struct rxrpc_call, accept_link);
600 list_del_init(&call->accept_link);
601 sk_acceptq_removed(&rx->sk);
602 rxrpc_see_call(call);
604 write_lock_bh(&call->state_lock);
605 switch (call->state) {
606 case RXRPC_CALL_SERVER_ACCEPTING:
607 __rxrpc_abort_call("REJ", call, 1, RX_USER_ABORT, -ECONNABORTED);
610 case RXRPC_CALL_COMPLETE:
618 write_unlock_bh(&call->state_lock);
619 write_unlock(&rx->call_lock);
621 rxrpc_send_abort_packet(call);
622 rxrpc_release_call(rx, call);
623 rxrpc_put_call(call, rxrpc_call_put);
625 rxrpc_service_prealloc(rx, GFP_KERNEL);
626 _leave(" = %d", ret);
631 * rxrpc_kernel_charge_accept - Charge up socket with preallocated calls
632 * @sock: The socket on which to preallocate
633 * @notify_rx: Event notification function for the call
634 * @user_attach_call: Func to attach call to user_call_ID
635 * @user_call_ID: The tag to attach to the preallocated call
636 * @gfp: The allocation conditions.
638 * Charge up the socket with preallocated calls, each with a user ID. A
639 * function should be provided to effect the attachment from the user's side.
640 * The user is given a ref to hold on the call.
642 * Note that the call may be come connected before this function returns.
644 int rxrpc_kernel_charge_accept(struct socket *sock,
645 rxrpc_notify_rx_t notify_rx,
646 rxrpc_user_attach_call_t user_attach_call,
647 unsigned long user_call_ID, gfp_t gfp)
649 struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
650 struct rxrpc_backlog *b = rx->backlog;
652 if (sock->sk->sk_state == RXRPC_CLOSE)
655 return rxrpc_service_prealloc_one(rx, b, notify_rx,
656 user_attach_call, user_call_ID,
659 EXPORT_SYMBOL(rxrpc_kernel_charge_accept);