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
12#include <linux/module.h>
13#include <linux/net.h>
14#include <linux/skbuff.h>
15#include <linux/errqueue.h>
16#include <linux/udp.h>
17#include <linux/in.h>
18#include <linux/in6.h>
19#include <linux/icmp.h>
20#include <linux/gfp.h>
21#include <net/sock.h>
22#include <net/af_rxrpc.h>
23#include <net/ip.h>
24#include "ar-internal.h"
25
26/*
27 * generate a connection-level abort
28 */
29static int rxrpc_busy(struct rxrpc_local *local, struct sockaddr_rxrpc *srx,
30		      struct rxrpc_header *hdr)
31{
32	struct msghdr msg;
33	struct kvec iov[1];
34	size_t len;
35	int ret;
36
37	_enter("%d,,", local->debug_id);
38
39	msg.msg_name	= &srx->transport.sin;
40	msg.msg_namelen	= sizeof(srx->transport.sin);
41	msg.msg_control	= NULL;
42	msg.msg_controllen = 0;
43	msg.msg_flags	= 0;
44
45	hdr->seq	= 0;
46	hdr->type	= RXRPC_PACKET_TYPE_BUSY;
47	hdr->flags	= 0;
48	hdr->userStatus	= 0;
49	hdr->_rsvd	= 0;
50
51	iov[0].iov_base	= hdr;
52	iov[0].iov_len	= sizeof(*hdr);
53
54	len = iov[0].iov_len;
55
56	hdr->serial = htonl(1);
57	_proto("Tx BUSY %%%u", ntohl(hdr->serial));
58
59	ret = kernel_sendmsg(local->socket, &msg, iov, 1, len);
60	if (ret < 0) {
61		_leave(" = -EAGAIN [sendmsg failed: %d]", ret);
62		return -EAGAIN;
63	}
64
65	_leave(" = 0");
66	return 0;
67}
68
69/*
70 * accept an incoming call that needs peer, transport and/or connection setting
71 * up
72 */
73static int rxrpc_accept_incoming_call(struct rxrpc_local *local,
74				      struct rxrpc_sock *rx,
75				      struct sk_buff *skb,
76				      struct sockaddr_rxrpc *srx)
77{
78	struct rxrpc_connection *conn;
79	struct rxrpc_transport *trans;
80	struct rxrpc_skb_priv *sp, *nsp;
81	struct rxrpc_peer *peer;
82	struct rxrpc_call *call;
83	struct sk_buff *notification;
84	int ret;
85
86	_enter("");
87
88	sp = rxrpc_skb(skb);
89
90	/* get a notification message to send to the server app */
91	notification = alloc_skb(0, GFP_NOFS);
92	if (!notification) {
93		_debug("no memory");
94		ret = -ENOMEM;
95		goto error_nofree;
96	}
97	rxrpc_new_skb(notification);
98	notification->mark = RXRPC_SKB_MARK_NEW_CALL;
99
100	peer = rxrpc_get_peer(srx, GFP_NOIO);
101	if (IS_ERR(peer)) {
102		_debug("no peer");
103		ret = -EBUSY;
104		goto error;
105	}
106
107	trans = rxrpc_get_transport(local, peer, GFP_NOIO);
108	rxrpc_put_peer(peer);
109	if (IS_ERR(trans)) {
110		_debug("no trans");
111		ret = -EBUSY;
112		goto error;
113	}
114
115	conn = rxrpc_incoming_connection(trans, &sp->hdr, GFP_NOIO);
116	rxrpc_put_transport(trans);
117	if (IS_ERR(conn)) {
118		_debug("no conn");
119		ret = PTR_ERR(conn);
120		goto error;
121	}
122
123	call = rxrpc_incoming_call(rx, conn, &sp->hdr, GFP_NOIO);
124	rxrpc_put_connection(conn);
125	if (IS_ERR(call)) {
126		_debug("no call");
127		ret = PTR_ERR(call);
128		goto error;
129	}
130
131	/* attach the call to the socket */
132	read_lock_bh(&local->services_lock);
133	if (rx->sk.sk_state == RXRPC_CLOSE)
134		goto invalid_service;
135
136	write_lock(&rx->call_lock);
137	if (!test_and_set_bit(RXRPC_CALL_INIT_ACCEPT, &call->flags)) {
138		rxrpc_get_call(call);
139
140		spin_lock(&call->conn->state_lock);
141		if (sp->hdr.securityIndex > 0 &&
142		    call->conn->state == RXRPC_CONN_SERVER_UNSECURED) {
143			_debug("await conn sec");
144			list_add_tail(&call->accept_link, &rx->secureq);
145			call->conn->state = RXRPC_CONN_SERVER_CHALLENGING;
146			atomic_inc(&call->conn->usage);
147			set_bit(RXRPC_CONN_CHALLENGE, &call->conn->events);
148			rxrpc_queue_conn(call->conn);
149		} else {
150			_debug("conn ready");
151			call->state = RXRPC_CALL_SERVER_ACCEPTING;
152			list_add_tail(&call->accept_link, &rx->acceptq);
153			rxrpc_get_call(call);
154			nsp = rxrpc_skb(notification);
155			nsp->call = call;
156
157			ASSERTCMP(atomic_read(&call->usage), >=, 3);
158
159			_debug("notify");
160			spin_lock(&call->lock);
161			ret = rxrpc_queue_rcv_skb(call, notification, true,
162						  false);
163			spin_unlock(&call->lock);
164			notification = NULL;
165			BUG_ON(ret < 0);
166		}
167		spin_unlock(&call->conn->state_lock);
168
169		_debug("queued");
170	}
171	write_unlock(&rx->call_lock);
172
173	_debug("process");
174	rxrpc_fast_process_packet(call, skb);
175
176	_debug("done");
177	read_unlock_bh(&local->services_lock);
178	rxrpc_free_skb(notification);
179	rxrpc_put_call(call);
180	_leave(" = 0");
181	return 0;
182
183invalid_service:
184	_debug("invalid");
185	read_unlock_bh(&local->services_lock);
186
187	read_lock_bh(&call->state_lock);
188	if (!test_bit(RXRPC_CALL_RELEASE, &call->flags) &&
189	    !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events)) {
190		rxrpc_get_call(call);
191		rxrpc_queue_call(call);
192	}
193	read_unlock_bh(&call->state_lock);
194	rxrpc_put_call(call);
195	ret = -ECONNREFUSED;
196error:
197	rxrpc_free_skb(notification);
198error_nofree:
199	_leave(" = %d", ret);
200	return ret;
201}
202
203/*
204 * accept incoming calls that need peer, transport and/or connection setting up
205 * - the packets we get are all incoming client DATA packets that have seq == 1
206 */
207void rxrpc_accept_incoming_calls(struct work_struct *work)
208{
209	struct rxrpc_local *local =
210		container_of(work, struct rxrpc_local, acceptor);
211	struct rxrpc_skb_priv *sp;
212	struct sockaddr_rxrpc srx;
213	struct rxrpc_sock *rx;
214	struct sk_buff *skb;
215	__be16 service_id;
216	int ret;
217
218	_enter("%d", local->debug_id);
219
220	read_lock_bh(&rxrpc_local_lock);
221	if (atomic_read(&local->usage) > 0)
222		rxrpc_get_local(local);
223	else
224		local = NULL;
225	read_unlock_bh(&rxrpc_local_lock);
226	if (!local) {
227		_leave(" [local dead]");
228		return;
229	}
230
231process_next_packet:
232	skb = skb_dequeue(&local->accept_queue);
233	if (!skb) {
234		rxrpc_put_local(local);
235		_leave("\n");
236		return;
237	}
238
239	_net("incoming call skb %p", skb);
240
241	sp = rxrpc_skb(skb);
242
243	/* determine the remote address */
244	memset(&srx, 0, sizeof(srx));
245	srx.srx_family = AF_RXRPC;
246	srx.transport.family = local->srx.transport.family;
247	srx.transport_type = local->srx.transport_type;
248	switch (srx.transport.family) {
249	case AF_INET:
250		srx.transport_len = sizeof(struct sockaddr_in);
251		srx.transport.sin.sin_port = udp_hdr(skb)->source;
252		srx.transport.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
253		break;
254	default:
255		goto busy;
256	}
257
258	/* get the socket providing the service */
259	service_id = sp->hdr.serviceId;
260	read_lock_bh(&local->services_lock);
261	list_for_each_entry(rx, &local->services, listen_link) {
262		if (rx->service_id == service_id &&
263		    rx->sk.sk_state != RXRPC_CLOSE)
264			goto found_service;
265	}
266	read_unlock_bh(&local->services_lock);
267	goto invalid_service;
268
269found_service:
270	_debug("found service %hd", ntohs(rx->service_id));
271	if (sk_acceptq_is_full(&rx->sk))
272		goto backlog_full;
273	sk_acceptq_added(&rx->sk);
274	sock_hold(&rx->sk);
275	read_unlock_bh(&local->services_lock);
276
277	ret = rxrpc_accept_incoming_call(local, rx, skb, &srx);
278	if (ret < 0)
279		sk_acceptq_removed(&rx->sk);
280	sock_put(&rx->sk);
281	switch (ret) {
282	case -ECONNRESET: /* old calls are ignored */
283	case -ECONNABORTED: /* aborted calls are reaborted or ignored */
284	case 0:
285		goto process_next_packet;
286	case -ECONNREFUSED:
287		goto invalid_service;
288	case -EBUSY:
289		goto busy;
290	case -EKEYREJECTED:
291		goto security_mismatch;
292	default:
293		BUG();
294	}
295
296backlog_full:
297	read_unlock_bh(&local->services_lock);
298busy:
299	rxrpc_busy(local, &srx, &sp->hdr);
300	rxrpc_free_skb(skb);
301	goto process_next_packet;
302
303invalid_service:
304	skb->priority = RX_INVALID_OPERATION;
305	rxrpc_reject_packet(local, skb);
306	goto process_next_packet;
307
308	/* can't change connection security type mid-flow */
309security_mismatch:
310	skb->priority = RX_PROTOCOL_ERROR;
311	rxrpc_reject_packet(local, skb);
312	goto process_next_packet;
313}
314
315/*
316 * handle acceptance of a call by userspace
317 * - assign the user call ID to the call at the front of the queue
318 */
319struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
320				     unsigned long user_call_ID)
321{
322	struct rxrpc_call *call;
323	struct rb_node *parent, **pp;
324	int ret;
325
326	_enter(",%lx", user_call_ID);
327
328	ASSERT(!irqs_disabled());
329
330	write_lock(&rx->call_lock);
331
332	ret = -ENODATA;
333	if (list_empty(&rx->acceptq))
334		goto out;
335
336	/* check the user ID isn't already in use */
337	ret = -EBADSLT;
338	pp = &rx->calls.rb_node;
339	parent = NULL;
340	while (*pp) {
341		parent = *pp;
342		call = rb_entry(parent, struct rxrpc_call, sock_node);
343
344		if (user_call_ID < call->user_call_ID)
345			pp = &(*pp)->rb_left;
346		else if (user_call_ID > call->user_call_ID)
347			pp = &(*pp)->rb_right;
348		else
349			goto out;
350	}
351
352	/* dequeue the first call and check it's still valid */
353	call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
354	list_del_init(&call->accept_link);
355	sk_acceptq_removed(&rx->sk);
356
357	write_lock_bh(&call->state_lock);
358	switch (call->state) {
359	case RXRPC_CALL_SERVER_ACCEPTING:
360		call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
361		break;
362	case RXRPC_CALL_REMOTELY_ABORTED:
363	case RXRPC_CALL_LOCALLY_ABORTED:
364		ret = -ECONNABORTED;
365		goto out_release;
366	case RXRPC_CALL_NETWORK_ERROR:
367		ret = call->conn->error;
368		goto out_release;
369	case RXRPC_CALL_DEAD:
370		ret = -ETIME;
371		goto out_discard;
372	default:
373		BUG();
374	}
375
376	/* formalise the acceptance */
377	call->user_call_ID = user_call_ID;
378	rb_link_node(&call->sock_node, parent, pp);
379	rb_insert_color(&call->sock_node, &rx->calls);
380	if (test_and_set_bit(RXRPC_CALL_HAS_USERID, &call->flags))
381		BUG();
382	if (test_and_set_bit(RXRPC_CALL_ACCEPTED, &call->events))
383		BUG();
384	rxrpc_queue_call(call);
385
386	rxrpc_get_call(call);
387	write_unlock_bh(&call->state_lock);
388	write_unlock(&rx->call_lock);
389	_leave(" = %p{%d}", call, call->debug_id);
390	return call;
391
392	/* if the call is already dying or dead, then we leave the socket's ref
393	 * on it to be released by rxrpc_dead_call_expired() as induced by
394	 * rxrpc_release_call() */
395out_release:
396	_debug("release %p", call);
397	if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
398	    !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
399		rxrpc_queue_call(call);
400out_discard:
401	write_unlock_bh(&call->state_lock);
402	_debug("discard %p", call);
403out:
404	write_unlock(&rx->call_lock);
405	_leave(" = %d", ret);
406	return ERR_PTR(ret);
407}
408
409/*
410 * handle rejectance of a call by userspace
411 * - reject the call at the front of the queue
412 */
413int rxrpc_reject_call(struct rxrpc_sock *rx)
414{
415	struct rxrpc_call *call;
416	int ret;
417
418	_enter("");
419
420	ASSERT(!irqs_disabled());
421
422	write_lock(&rx->call_lock);
423
424	ret = -ENODATA;
425	if (list_empty(&rx->acceptq))
426		goto out;
427
428	/* dequeue the first call and check it's still valid */
429	call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
430	list_del_init(&call->accept_link);
431	sk_acceptq_removed(&rx->sk);
432
433	write_lock_bh(&call->state_lock);
434	switch (call->state) {
435	case RXRPC_CALL_SERVER_ACCEPTING:
436		call->state = RXRPC_CALL_SERVER_BUSY;
437		if (test_and_set_bit(RXRPC_CALL_REJECT_BUSY, &call->events))
438			rxrpc_queue_call(call);
439		ret = 0;
440		goto out_release;
441	case RXRPC_CALL_REMOTELY_ABORTED:
442	case RXRPC_CALL_LOCALLY_ABORTED:
443		ret = -ECONNABORTED;
444		goto out_release;
445	case RXRPC_CALL_NETWORK_ERROR:
446		ret = call->conn->error;
447		goto out_release;
448	case RXRPC_CALL_DEAD:
449		ret = -ETIME;
450		goto out_discard;
451	default:
452		BUG();
453	}
454
455	/* if the call is already dying or dead, then we leave the socket's ref
456	 * on it to be released by rxrpc_dead_call_expired() as induced by
457	 * rxrpc_release_call() */
458out_release:
459	_debug("release %p", call);
460	if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
461	    !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
462		rxrpc_queue_call(call);
463out_discard:
464	write_unlock_bh(&call->state_lock);
465	_debug("discard %p", call);
466out:
467	write_unlock(&rx->call_lock);
468	_leave(" = %d", ret);
469	return ret;
470}
471
472/**
473 * rxrpc_kernel_accept_call - Allow a kernel service to accept an incoming call
474 * @sock: The socket on which the impending call is waiting
475 * @user_call_ID: The tag to attach to the call
476 *
477 * Allow a kernel service to accept an incoming call, assuming the incoming
478 * call is still valid.
479 */
480struct rxrpc_call *rxrpc_kernel_accept_call(struct socket *sock,
481					    unsigned long user_call_ID)
482{
483	struct rxrpc_call *call;
484
485	_enter(",%lx", user_call_ID);
486	call = rxrpc_accept_call(rxrpc_sk(sock->sk), user_call_ID);
487	_leave(" = %p", call);
488	return call;
489}
490
491EXPORT_SYMBOL(rxrpc_kernel_accept_call);
492
493/**
494 * rxrpc_kernel_reject_call - Allow a kernel service to reject an incoming call
495 * @sock: The socket on which the impending call is waiting
496 *
497 * Allow a kernel service to reject an incoming call with a BUSY message,
498 * assuming the incoming call is still valid.
499 */
500int rxrpc_kernel_reject_call(struct socket *sock)
501{
502	int ret;
503
504	_enter("");
505	ret = rxrpc_reject_call(rxrpc_sk(sock->sk));
506	_leave(" = %d", ret);
507	return ret;
508}
509
510EXPORT_SYMBOL(rxrpc_kernel_reject_call);
511