xref: /openbmc/linux/net/llc/af_llc.c (revision 9659281c)
1 /*
2  * af_llc.c - LLC User Interface SAPs
3  * Description:
4  *   Functions in this module are implementation of socket based llc
5  *   communications for the Linux operating system. Support of llc class
6  *   one and class two is provided via SOCK_DGRAM and SOCK_STREAM
7  *   respectively.
8  *
9  *   An llc2 connection is (mac + sap), only one llc2 sap connection
10  *   is allowed per mac. Though one sap may have multiple mac + sap
11  *   connections.
12  *
13  * Copyright (c) 2001 by Jay Schulist <jschlst@samba.org>
14  *		 2002-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
15  *
16  * This program can be redistributed or modified under the terms of the
17  * GNU General Public License as published by the Free Software Foundation.
18  * This program is distributed without any warranty or implied warranty
19  * of merchantability or fitness for a particular purpose.
20  *
21  * See the GNU General Public License for more details.
22  */
23 #include <linux/compiler.h>
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/rtnetlink.h>
27 #include <linux/init.h>
28 #include <linux/slab.h>
29 #include <linux/sched/signal.h>
30 
31 #include <net/llc.h>
32 #include <net/llc_sap.h>
33 #include <net/llc_pdu.h>
34 #include <net/llc_conn.h>
35 #include <net/tcp_states.h>
36 
37 /* remember: uninitialized global data is zeroed because its in .bss */
38 static u16 llc_ui_sap_last_autoport = LLC_SAP_DYN_START;
39 static u16 llc_ui_sap_link_no_max[256];
40 static struct sockaddr_llc llc_ui_addrnull;
41 static const struct proto_ops llc_ui_ops;
42 
43 static bool llc_ui_wait_for_conn(struct sock *sk, long timeout);
44 static int llc_ui_wait_for_disc(struct sock *sk, long timeout);
45 static int llc_ui_wait_for_busy_core(struct sock *sk, long timeout);
46 
47 #if 0
48 #define dprintk(args...) printk(KERN_DEBUG args)
49 #else
50 #define dprintk(args...) do {} while (0)
51 #endif
52 
53 /* Maybe we'll add some more in the future. */
54 #define LLC_CMSG_PKTINFO	1
55 
56 
57 /**
58  *	llc_ui_next_link_no - return the next unused link number for a sap
59  *	@sap: Address of sap to get link number from.
60  *
61  *	Return the next unused link number for a given sap.
62  */
63 static inline u16 llc_ui_next_link_no(int sap)
64 {
65 	return llc_ui_sap_link_no_max[sap]++;
66 }
67 
68 /**
69  *	llc_proto_type - return eth protocol for ARP header type
70  *	@arphrd: ARP header type.
71  *
72  *	Given an ARP header type return the corresponding ethernet protocol.
73  */
74 static inline __be16 llc_proto_type(u16 arphrd)
75 {
76 	return htons(ETH_P_802_2);
77 }
78 
79 /**
80  *	llc_ui_addr_null - determines if a address structure is null
81  *	@addr: Address to test if null.
82  */
83 static inline u8 llc_ui_addr_null(struct sockaddr_llc *addr)
84 {
85 	return !memcmp(addr, &llc_ui_addrnull, sizeof(*addr));
86 }
87 
88 /**
89  *	llc_ui_header_len - return length of llc header based on operation
90  *	@sk: Socket which contains a valid llc socket type.
91  *	@addr: Complete sockaddr_llc structure received from the user.
92  *
93  *	Provide the length of the llc header depending on what kind of
94  *	operation the user would like to perform and the type of socket.
95  *	Returns the correct llc header length.
96  */
97 static inline u8 llc_ui_header_len(struct sock *sk, struct sockaddr_llc *addr)
98 {
99 	u8 rc = LLC_PDU_LEN_U;
100 
101 	if (addr->sllc_test)
102 		rc = LLC_PDU_LEN_U;
103 	else if (addr->sllc_xid)
104 		/* We need to expand header to sizeof(struct llc_xid_info)
105 		 * since llc_pdu_init_as_xid_cmd() sets 4,5,6 bytes of LLC header
106 		 * as XID PDU. In llc_ui_sendmsg() we reserved header size and then
107 		 * filled all other space with user data. If we won't reserve this
108 		 * bytes, llc_pdu_init_as_xid_cmd() will overwrite user data
109 		 */
110 		rc = LLC_PDU_LEN_U_XID;
111 	else if (sk->sk_type == SOCK_STREAM)
112 		rc = LLC_PDU_LEN_I;
113 	return rc;
114 }
115 
116 /**
117  *	llc_ui_send_data - send data via reliable llc2 connection
118  *	@sk: Connection the socket is using.
119  *	@skb: Data the user wishes to send.
120  *	@noblock: can we block waiting for data?
121  *
122  *	Send data via reliable llc2 connection.
123  *	Returns 0 upon success, non-zero if action did not succeed.
124  *
125  *	This function always consumes a reference to the skb.
126  */
127 static int llc_ui_send_data(struct sock* sk, struct sk_buff *skb, int noblock)
128 {
129 	struct llc_sock* llc = llc_sk(sk);
130 
131 	if (unlikely(llc_data_accept_state(llc->state) ||
132 		     llc->remote_busy_flag ||
133 		     llc->p_flag)) {
134 		long timeout = sock_sndtimeo(sk, noblock);
135 		int rc;
136 
137 		rc = llc_ui_wait_for_busy_core(sk, timeout);
138 		if (rc) {
139 			kfree_skb(skb);
140 			return rc;
141 		}
142 	}
143 	return llc_build_and_send_pkt(sk, skb);
144 }
145 
146 static void llc_ui_sk_init(struct socket *sock, struct sock *sk)
147 {
148 	sock_graft(sk, sock);
149 	sk->sk_type	= sock->type;
150 	sock->ops	= &llc_ui_ops;
151 }
152 
153 static struct proto llc_proto = {
154 	.name	  = "LLC",
155 	.owner	  = THIS_MODULE,
156 	.obj_size = sizeof(struct llc_sock),
157 	.slab_flags = SLAB_TYPESAFE_BY_RCU,
158 };
159 
160 /**
161  *	llc_ui_create - alloc and init a new llc_ui socket
162  *	@net: network namespace (must be default network)
163  *	@sock: Socket to initialize and attach allocated sk to.
164  *	@protocol: Unused.
165  *	@kern: on behalf of kernel or userspace
166  *
167  *	Allocate and initialize a new llc_ui socket, validate the user wants a
168  *	socket type we have available.
169  *	Returns 0 upon success, negative upon failure.
170  */
171 static int llc_ui_create(struct net *net, struct socket *sock, int protocol,
172 			 int kern)
173 {
174 	struct sock *sk;
175 	int rc = -ESOCKTNOSUPPORT;
176 
177 	if (!ns_capable(net->user_ns, CAP_NET_RAW))
178 		return -EPERM;
179 
180 	if (!net_eq(net, &init_net))
181 		return -EAFNOSUPPORT;
182 
183 	if (likely(sock->type == SOCK_DGRAM || sock->type == SOCK_STREAM)) {
184 		rc = -ENOMEM;
185 		sk = llc_sk_alloc(net, PF_LLC, GFP_KERNEL, &llc_proto, kern);
186 		if (sk) {
187 			rc = 0;
188 			llc_ui_sk_init(sock, sk);
189 		}
190 	}
191 	return rc;
192 }
193 
194 /**
195  *	llc_ui_release - shutdown socket
196  *	@sock: Socket to release.
197  *
198  *	Shutdown and deallocate an existing socket.
199  */
200 static int llc_ui_release(struct socket *sock)
201 {
202 	struct sock *sk = sock->sk;
203 	struct llc_sock *llc;
204 
205 	if (unlikely(sk == NULL))
206 		goto out;
207 	sock_hold(sk);
208 	lock_sock(sk);
209 	llc = llc_sk(sk);
210 	dprintk("%s: closing local(%02X) remote(%02X)\n", __func__,
211 		llc->laddr.lsap, llc->daddr.lsap);
212 	if (!llc_send_disc(sk))
213 		llc_ui_wait_for_disc(sk, sk->sk_rcvtimeo);
214 	if (!sock_flag(sk, SOCK_ZAPPED)) {
215 		struct llc_sap *sap = llc->sap;
216 
217 		/* Hold this for release_sock(), so that llc_backlog_rcv()
218 		 * could still use it.
219 		 */
220 		llc_sap_hold(sap);
221 		llc_sap_remove_socket(llc->sap, sk);
222 		release_sock(sk);
223 		llc_sap_put(sap);
224 	} else {
225 		release_sock(sk);
226 	}
227 	if (llc->dev)
228 		dev_put(llc->dev);
229 	sock_put(sk);
230 	llc_sk_free(sk);
231 out:
232 	return 0;
233 }
234 
235 /**
236  *	llc_ui_autoport - provide dynamically allocate SAP number
237  *
238  *	Provide the caller with a dynamically allocated SAP number according
239  *	to the rules that are set in this function. Returns: 0, upon failure,
240  *	SAP number otherwise.
241  */
242 static int llc_ui_autoport(void)
243 {
244 	struct llc_sap *sap;
245 	int i, tries = 0;
246 
247 	while (tries < LLC_SAP_DYN_TRIES) {
248 		for (i = llc_ui_sap_last_autoport;
249 		     i < LLC_SAP_DYN_STOP; i += 2) {
250 			sap = llc_sap_find(i);
251 			if (!sap) {
252 				llc_ui_sap_last_autoport = i + 2;
253 				goto out;
254 			}
255 			llc_sap_put(sap);
256 		}
257 		llc_ui_sap_last_autoport = LLC_SAP_DYN_START;
258 		tries++;
259 	}
260 	i = 0;
261 out:
262 	return i;
263 }
264 
265 /**
266  *	llc_ui_autobind - automatically bind a socket to a sap
267  *	@sock: socket to bind
268  *	@addr: address to connect to
269  *
270  * 	Used by llc_ui_connect and llc_ui_sendmsg when the user hasn't
271  * 	specifically used llc_ui_bind to bind to an specific address/sap
272  *
273  *	Returns: 0 upon success, negative otherwise.
274  */
275 static int llc_ui_autobind(struct socket *sock, struct sockaddr_llc *addr)
276 {
277 	struct sock *sk = sock->sk;
278 	struct llc_sock *llc = llc_sk(sk);
279 	struct llc_sap *sap;
280 	int rc = -EINVAL;
281 
282 	if (!sock_flag(sk, SOCK_ZAPPED))
283 		goto out;
284 	if (!addr->sllc_arphrd)
285 		addr->sllc_arphrd = ARPHRD_ETHER;
286 	if (addr->sllc_arphrd != ARPHRD_ETHER)
287 		goto out;
288 	rc = -ENODEV;
289 	if (sk->sk_bound_dev_if) {
290 		llc->dev = dev_get_by_index(&init_net, sk->sk_bound_dev_if);
291 		if (llc->dev && addr->sllc_arphrd != llc->dev->type) {
292 			dev_put(llc->dev);
293 			llc->dev = NULL;
294 		}
295 	} else
296 		llc->dev = dev_getfirstbyhwtype(&init_net, addr->sllc_arphrd);
297 	if (!llc->dev)
298 		goto out;
299 	rc = -EUSERS;
300 	llc->laddr.lsap = llc_ui_autoport();
301 	if (!llc->laddr.lsap)
302 		goto out;
303 	rc = -EBUSY; /* some other network layer is using the sap */
304 	sap = llc_sap_open(llc->laddr.lsap, NULL);
305 	if (!sap)
306 		goto out;
307 	memcpy(llc->laddr.mac, llc->dev->dev_addr, IFHWADDRLEN);
308 	memcpy(&llc->addr, addr, sizeof(llc->addr));
309 	/* assign new connection to its SAP */
310 	llc_sap_add_socket(sap, sk);
311 	sock_reset_flag(sk, SOCK_ZAPPED);
312 	rc = 0;
313 out:
314 	return rc;
315 }
316 
317 /**
318  *	llc_ui_bind - bind a socket to a specific address.
319  *	@sock: Socket to bind an address to.
320  *	@uaddr: Address the user wants the socket bound to.
321  *	@addrlen: Length of the uaddr structure.
322  *
323  *	Bind a socket to a specific address. For llc a user is able to bind to
324  *	a specific sap only or mac + sap.
325  *	If the user desires to bind to a specific mac + sap, it is possible to
326  *	have multiple sap connections via multiple macs.
327  *	Bind and autobind for that matter must enforce the correct sap usage
328  *	otherwise all hell will break loose.
329  *	Returns: 0 upon success, negative otherwise.
330  */
331 static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen)
332 {
333 	struct sockaddr_llc *addr = (struct sockaddr_llc *)uaddr;
334 	struct sock *sk = sock->sk;
335 	struct llc_sock *llc = llc_sk(sk);
336 	struct llc_sap *sap;
337 	int rc = -EINVAL;
338 
339 	lock_sock(sk);
340 	if (unlikely(!sock_flag(sk, SOCK_ZAPPED) || addrlen != sizeof(*addr)))
341 		goto out;
342 	rc = -EAFNOSUPPORT;
343 	if (!addr->sllc_arphrd)
344 		addr->sllc_arphrd = ARPHRD_ETHER;
345 	if (unlikely(addr->sllc_family != AF_LLC || addr->sllc_arphrd != ARPHRD_ETHER))
346 		goto out;
347 	dprintk("%s: binding %02X\n", __func__, addr->sllc_sap);
348 	rc = -ENODEV;
349 	rcu_read_lock();
350 	if (sk->sk_bound_dev_if) {
351 		llc->dev = dev_get_by_index_rcu(&init_net, sk->sk_bound_dev_if);
352 		if (llc->dev) {
353 			if (is_zero_ether_addr(addr->sllc_mac))
354 				memcpy(addr->sllc_mac, llc->dev->dev_addr,
355 				       IFHWADDRLEN);
356 			if (addr->sllc_arphrd != llc->dev->type ||
357 			    !ether_addr_equal(addr->sllc_mac,
358 					      llc->dev->dev_addr)) {
359 				rc = -EINVAL;
360 				llc->dev = NULL;
361 			}
362 		}
363 	} else
364 		llc->dev = dev_getbyhwaddr_rcu(&init_net, addr->sllc_arphrd,
365 					   addr->sllc_mac);
366 	if (llc->dev)
367 		dev_hold(llc->dev);
368 	rcu_read_unlock();
369 	if (!llc->dev)
370 		goto out;
371 	if (!addr->sllc_sap) {
372 		rc = -EUSERS;
373 		addr->sllc_sap = llc_ui_autoport();
374 		if (!addr->sllc_sap)
375 			goto out;
376 	}
377 	sap = llc_sap_find(addr->sllc_sap);
378 	if (!sap) {
379 		sap = llc_sap_open(addr->sllc_sap, NULL);
380 		rc = -EBUSY; /* some other network layer is using the sap */
381 		if (!sap)
382 			goto out;
383 	} else {
384 		struct llc_addr laddr, daddr;
385 		struct sock *ask;
386 
387 		memset(&laddr, 0, sizeof(laddr));
388 		memset(&daddr, 0, sizeof(daddr));
389 		/*
390 		 * FIXME: check if the address is multicast,
391 		 * 	  only SOCK_DGRAM can do this.
392 		 */
393 		memcpy(laddr.mac, addr->sllc_mac, IFHWADDRLEN);
394 		laddr.lsap = addr->sllc_sap;
395 		rc = -EADDRINUSE; /* mac + sap clash. */
396 		ask = llc_lookup_established(sap, &daddr, &laddr);
397 		if (ask) {
398 			sock_put(ask);
399 			goto out_put;
400 		}
401 	}
402 	llc->laddr.lsap = addr->sllc_sap;
403 	memcpy(llc->laddr.mac, addr->sllc_mac, IFHWADDRLEN);
404 	memcpy(&llc->addr, addr, sizeof(llc->addr));
405 	/* assign new connection to its SAP */
406 	llc_sap_add_socket(sap, sk);
407 	sock_reset_flag(sk, SOCK_ZAPPED);
408 	rc = 0;
409 out_put:
410 	llc_sap_put(sap);
411 out:
412 	release_sock(sk);
413 	return rc;
414 }
415 
416 /**
417  *	llc_ui_shutdown - shutdown a connect llc2 socket.
418  *	@sock: Socket to shutdown.
419  *	@how: What part of the socket to shutdown.
420  *
421  *	Shutdown a connected llc2 socket. Currently this function only supports
422  *	shutting down both sends and receives (2), we could probably make this
423  *	function such that a user can shutdown only half the connection but not
424  *	right now.
425  *	Returns: 0 upon success, negative otherwise.
426  */
427 static int llc_ui_shutdown(struct socket *sock, int how)
428 {
429 	struct sock *sk = sock->sk;
430 	int rc = -ENOTCONN;
431 
432 	lock_sock(sk);
433 	if (unlikely(sk->sk_state != TCP_ESTABLISHED))
434 		goto out;
435 	rc = -EINVAL;
436 	if (how != 2)
437 		goto out;
438 	rc = llc_send_disc(sk);
439 	if (!rc)
440 		rc = llc_ui_wait_for_disc(sk, sk->sk_rcvtimeo);
441 	/* Wake up anyone sleeping in poll */
442 	sk->sk_state_change(sk);
443 out:
444 	release_sock(sk);
445 	return rc;
446 }
447 
448 /**
449  *	llc_ui_connect - Connect to a remote llc2 mac + sap.
450  *	@sock: Socket which will be connected to the remote destination.
451  *	@uaddr: Remote and possibly the local address of the new connection.
452  *	@addrlen: Size of uaddr structure.
453  *	@flags: Operational flags specified by the user.
454  *
455  *	Connect to a remote llc2 mac + sap. The caller must specify the
456  *	destination mac and address to connect to. If the user hasn't previously
457  *	called bind(2) with a smac the address of the first interface of the
458  *	specified arp type will be used.
459  *	This function will autobind if user did not previously call bind.
460  *	Returns: 0 upon success, negative otherwise.
461  */
462 static int llc_ui_connect(struct socket *sock, struct sockaddr *uaddr,
463 			  int addrlen, int flags)
464 {
465 	struct sock *sk = sock->sk;
466 	struct llc_sock *llc = llc_sk(sk);
467 	struct sockaddr_llc *addr = (struct sockaddr_llc *)uaddr;
468 	int rc = -EINVAL;
469 
470 	lock_sock(sk);
471 	if (unlikely(addrlen != sizeof(*addr)))
472 		goto out;
473 	rc = -EAFNOSUPPORT;
474 	if (unlikely(addr->sllc_family != AF_LLC))
475 		goto out;
476 	if (unlikely(sk->sk_type != SOCK_STREAM))
477 		goto out;
478 	rc = -EALREADY;
479 	if (unlikely(sock->state == SS_CONNECTING))
480 		goto out;
481 	/* bind connection to sap if user hasn't done it. */
482 	if (sock_flag(sk, SOCK_ZAPPED)) {
483 		/* bind to sap with null dev, exclusive */
484 		rc = llc_ui_autobind(sock, addr);
485 		if (rc)
486 			goto out;
487 	}
488 	llc->daddr.lsap = addr->sllc_sap;
489 	memcpy(llc->daddr.mac, addr->sllc_mac, IFHWADDRLEN);
490 	sock->state = SS_CONNECTING;
491 	sk->sk_state   = TCP_SYN_SENT;
492 	llc->link   = llc_ui_next_link_no(llc->sap->laddr.lsap);
493 	rc = llc_establish_connection(sk, llc->dev->dev_addr,
494 				      addr->sllc_mac, addr->sllc_sap);
495 	if (rc) {
496 		dprintk("%s: llc_ui_send_conn failed :-(\n", __func__);
497 		sock->state  = SS_UNCONNECTED;
498 		sk->sk_state = TCP_CLOSE;
499 		goto out;
500 	}
501 
502 	if (sk->sk_state == TCP_SYN_SENT) {
503 		const long timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
504 
505 		if (!timeo || !llc_ui_wait_for_conn(sk, timeo))
506 			goto out;
507 
508 		rc = sock_intr_errno(timeo);
509 		if (signal_pending(current))
510 			goto out;
511 	}
512 
513 	if (sk->sk_state == TCP_CLOSE)
514 		goto sock_error;
515 
516 	sock->state = SS_CONNECTED;
517 	rc = 0;
518 out:
519 	release_sock(sk);
520 	return rc;
521 sock_error:
522 	rc = sock_error(sk) ? : -ECONNABORTED;
523 	sock->state = SS_UNCONNECTED;
524 	goto out;
525 }
526 
527 /**
528  *	llc_ui_listen - allow a normal socket to accept incoming connections
529  *	@sock: Socket to allow incoming connections on.
530  *	@backlog: Number of connections to queue.
531  *
532  *	Allow a normal socket to accept incoming connections.
533  *	Returns 0 upon success, negative otherwise.
534  */
535 static int llc_ui_listen(struct socket *sock, int backlog)
536 {
537 	struct sock *sk = sock->sk;
538 	int rc = -EINVAL;
539 
540 	lock_sock(sk);
541 	if (unlikely(sock->state != SS_UNCONNECTED))
542 		goto out;
543 	rc = -EOPNOTSUPP;
544 	if (unlikely(sk->sk_type != SOCK_STREAM))
545 		goto out;
546 	rc = -EAGAIN;
547 	if (sock_flag(sk, SOCK_ZAPPED))
548 		goto out;
549 	rc = 0;
550 	if (!(unsigned int)backlog)	/* BSDism */
551 		backlog = 1;
552 	sk->sk_max_ack_backlog = backlog;
553 	if (sk->sk_state != TCP_LISTEN) {
554 		sk->sk_ack_backlog = 0;
555 		sk->sk_state	   = TCP_LISTEN;
556 	}
557 	sk->sk_socket->flags |= __SO_ACCEPTCON;
558 out:
559 	release_sock(sk);
560 	return rc;
561 }
562 
563 static int llc_ui_wait_for_disc(struct sock *sk, long timeout)
564 {
565 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
566 	int rc = 0;
567 
568 	add_wait_queue(sk_sleep(sk), &wait);
569 	while (1) {
570 		if (sk_wait_event(sk, &timeout, sk->sk_state == TCP_CLOSE, &wait))
571 			break;
572 		rc = -ERESTARTSYS;
573 		if (signal_pending(current))
574 			break;
575 		rc = -EAGAIN;
576 		if (!timeout)
577 			break;
578 		rc = 0;
579 	}
580 	remove_wait_queue(sk_sleep(sk), &wait);
581 	return rc;
582 }
583 
584 static bool llc_ui_wait_for_conn(struct sock *sk, long timeout)
585 {
586 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
587 
588 	add_wait_queue(sk_sleep(sk), &wait);
589 	while (1) {
590 		if (sk_wait_event(sk, &timeout, sk->sk_state != TCP_SYN_SENT, &wait))
591 			break;
592 		if (signal_pending(current) || !timeout)
593 			break;
594 	}
595 	remove_wait_queue(sk_sleep(sk), &wait);
596 	return timeout;
597 }
598 
599 static int llc_ui_wait_for_busy_core(struct sock *sk, long timeout)
600 {
601 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
602 	struct llc_sock *llc = llc_sk(sk);
603 	int rc;
604 
605 	add_wait_queue(sk_sleep(sk), &wait);
606 	while (1) {
607 		rc = 0;
608 		if (sk_wait_event(sk, &timeout,
609 				  (sk->sk_shutdown & RCV_SHUTDOWN) ||
610 				  (!llc_data_accept_state(llc->state) &&
611 				   !llc->remote_busy_flag &&
612 				   !llc->p_flag), &wait))
613 			break;
614 		rc = -ERESTARTSYS;
615 		if (signal_pending(current))
616 			break;
617 		rc = -EAGAIN;
618 		if (!timeout)
619 			break;
620 	}
621 	remove_wait_queue(sk_sleep(sk), &wait);
622 	return rc;
623 }
624 
625 static int llc_wait_data(struct sock *sk, long timeo)
626 {
627 	int rc;
628 
629 	while (1) {
630 		/*
631 		 * POSIX 1003.1g mandates this order.
632 		 */
633 		rc = sock_error(sk);
634 		if (rc)
635 			break;
636 		rc = 0;
637 		if (sk->sk_shutdown & RCV_SHUTDOWN)
638 			break;
639 		rc = -EAGAIN;
640 		if (!timeo)
641 			break;
642 		rc = sock_intr_errno(timeo);
643 		if (signal_pending(current))
644 			break;
645 		rc = 0;
646 		if (sk_wait_data(sk, &timeo, NULL))
647 			break;
648 	}
649 	return rc;
650 }
651 
652 static void llc_cmsg_rcv(struct msghdr *msg, struct sk_buff *skb)
653 {
654 	struct llc_sock *llc = llc_sk(skb->sk);
655 
656 	if (llc->cmsg_flags & LLC_CMSG_PKTINFO) {
657 		struct llc_pktinfo info;
658 
659 		memset(&info, 0, sizeof(info));
660 		info.lpi_ifindex = llc_sk(skb->sk)->dev->ifindex;
661 		llc_pdu_decode_dsap(skb, &info.lpi_sap);
662 		llc_pdu_decode_da(skb, info.lpi_mac);
663 		put_cmsg(msg, SOL_LLC, LLC_OPT_PKTINFO, sizeof(info), &info);
664 	}
665 }
666 
667 /**
668  *	llc_ui_accept - accept a new incoming connection.
669  *	@sock: Socket which connections arrive on.
670  *	@newsock: Socket to move incoming connection to.
671  *	@flags: User specified operational flags.
672  *	@kern: If the socket is kernel internal
673  *
674  *	Accept a new incoming connection.
675  *	Returns 0 upon success, negative otherwise.
676  */
677 static int llc_ui_accept(struct socket *sock, struct socket *newsock, int flags,
678 			 bool kern)
679 {
680 	struct sock *sk = sock->sk, *newsk;
681 	struct llc_sock *llc, *newllc;
682 	struct sk_buff *skb;
683 	int rc = -EOPNOTSUPP;
684 
685 	dprintk("%s: accepting on %02X\n", __func__,
686 		llc_sk(sk)->laddr.lsap);
687 	lock_sock(sk);
688 	if (unlikely(sk->sk_type != SOCK_STREAM))
689 		goto out;
690 	rc = -EINVAL;
691 	if (unlikely(sock->state != SS_UNCONNECTED ||
692 		     sk->sk_state != TCP_LISTEN))
693 		goto out;
694 	/* wait for a connection to arrive. */
695 	if (skb_queue_empty(&sk->sk_receive_queue)) {
696 		rc = llc_wait_data(sk, sk->sk_rcvtimeo);
697 		if (rc)
698 			goto out;
699 	}
700 	dprintk("%s: got a new connection on %02X\n", __func__,
701 		llc_sk(sk)->laddr.lsap);
702 	skb = skb_dequeue(&sk->sk_receive_queue);
703 	rc = -EINVAL;
704 	if (!skb->sk)
705 		goto frees;
706 	rc = 0;
707 	newsk = skb->sk;
708 	/* attach connection to a new socket. */
709 	llc_ui_sk_init(newsock, newsk);
710 	sock_reset_flag(newsk, SOCK_ZAPPED);
711 	newsk->sk_state		= TCP_ESTABLISHED;
712 	newsock->state		= SS_CONNECTED;
713 	llc			= llc_sk(sk);
714 	newllc			= llc_sk(newsk);
715 	memcpy(&newllc->addr, &llc->addr, sizeof(newllc->addr));
716 	newllc->link = llc_ui_next_link_no(newllc->laddr.lsap);
717 
718 	/* put original socket back into a clean listen state. */
719 	sk->sk_state = TCP_LISTEN;
720 	sk_acceptq_removed(sk);
721 	dprintk("%s: ok success on %02X, client on %02X\n", __func__,
722 		llc_sk(sk)->addr.sllc_sap, newllc->daddr.lsap);
723 frees:
724 	kfree_skb(skb);
725 out:
726 	release_sock(sk);
727 	return rc;
728 }
729 
730 /**
731  *	llc_ui_recvmsg - copy received data to the socket user.
732  *	@sock: Socket to copy data from.
733  *	@msg: Various user space related information.
734  *	@len: Size of user buffer.
735  *	@flags: User specified flags.
736  *
737  *	Copy received data to the socket user.
738  *	Returns non-negative upon success, negative otherwise.
739  */
740 static int llc_ui_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
741 			  int flags)
742 {
743 	DECLARE_SOCKADDR(struct sockaddr_llc *, uaddr, msg->msg_name);
744 	const int nonblock = flags & MSG_DONTWAIT;
745 	struct sk_buff *skb = NULL;
746 	struct sock *sk = sock->sk;
747 	struct llc_sock *llc = llc_sk(sk);
748 	size_t copied = 0;
749 	u32 peek_seq = 0;
750 	u32 *seq, skb_len;
751 	unsigned long used;
752 	int target;	/* Read at least this many bytes */
753 	long timeo;
754 
755 	lock_sock(sk);
756 	copied = -ENOTCONN;
757 	if (unlikely(sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_LISTEN))
758 		goto out;
759 
760 	timeo = sock_rcvtimeo(sk, nonblock);
761 
762 	seq = &llc->copied_seq;
763 	if (flags & MSG_PEEK) {
764 		peek_seq = llc->copied_seq;
765 		seq = &peek_seq;
766 	}
767 
768 	target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
769 	copied = 0;
770 
771 	do {
772 		u32 offset;
773 
774 		/*
775 		 * We need to check signals first, to get correct SIGURG
776 		 * handling. FIXME: Need to check this doesn't impact 1003.1g
777 		 * and move it down to the bottom of the loop
778 		 */
779 		if (signal_pending(current)) {
780 			if (copied)
781 				break;
782 			copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
783 			break;
784 		}
785 
786 		/* Next get a buffer. */
787 
788 		skb = skb_peek(&sk->sk_receive_queue);
789 		if (skb) {
790 			offset = *seq;
791 			goto found_ok_skb;
792 		}
793 		/* Well, if we have backlog, try to process it now yet. */
794 
795 		if (copied >= target && !READ_ONCE(sk->sk_backlog.tail))
796 			break;
797 
798 		if (copied) {
799 			if (sk->sk_err ||
800 			    sk->sk_state == TCP_CLOSE ||
801 			    (sk->sk_shutdown & RCV_SHUTDOWN) ||
802 			    !timeo ||
803 			    (flags & MSG_PEEK))
804 				break;
805 		} else {
806 			if (sock_flag(sk, SOCK_DONE))
807 				break;
808 
809 			if (sk->sk_err) {
810 				copied = sock_error(sk);
811 				break;
812 			}
813 			if (sk->sk_shutdown & RCV_SHUTDOWN)
814 				break;
815 
816 			if (sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_CLOSE) {
817 				if (!sock_flag(sk, SOCK_DONE)) {
818 					/*
819 					 * This occurs when user tries to read
820 					 * from never connected socket.
821 					 */
822 					copied = -ENOTCONN;
823 					break;
824 				}
825 				break;
826 			}
827 			if (!timeo) {
828 				copied = -EAGAIN;
829 				break;
830 			}
831 		}
832 
833 		if (copied >= target) { /* Do not sleep, just process backlog. */
834 			release_sock(sk);
835 			lock_sock(sk);
836 		} else
837 			sk_wait_data(sk, &timeo, NULL);
838 
839 		if ((flags & MSG_PEEK) && peek_seq != llc->copied_seq) {
840 			net_dbg_ratelimited("LLC(%s:%d): Application bug, race in MSG_PEEK\n",
841 					    current->comm,
842 					    task_pid_nr(current));
843 			peek_seq = llc->copied_seq;
844 		}
845 		continue;
846 	found_ok_skb:
847 		skb_len = skb->len;
848 		/* Ok so how much can we use? */
849 		used = skb->len - offset;
850 		if (len < used)
851 			used = len;
852 
853 		if (!(flags & MSG_TRUNC)) {
854 			int rc = skb_copy_datagram_msg(skb, offset, msg, used);
855 			if (rc) {
856 				/* Exception. Bailout! */
857 				if (!copied)
858 					copied = -EFAULT;
859 				break;
860 			}
861 		}
862 
863 		*seq += used;
864 		copied += used;
865 		len -= used;
866 
867 		/* For non stream protcols we get one packet per recvmsg call */
868 		if (sk->sk_type != SOCK_STREAM)
869 			goto copy_uaddr;
870 
871 		if (!(flags & MSG_PEEK)) {
872 			skb_unlink(skb, &sk->sk_receive_queue);
873 			kfree_skb(skb);
874 			*seq = 0;
875 		}
876 
877 		/* Partial read */
878 		if (used + offset < skb_len)
879 			continue;
880 	} while (len > 0);
881 
882 out:
883 	release_sock(sk);
884 	return copied;
885 copy_uaddr:
886 	if (uaddr != NULL && skb != NULL) {
887 		memcpy(uaddr, llc_ui_skb_cb(skb), sizeof(*uaddr));
888 		msg->msg_namelen = sizeof(*uaddr);
889 	}
890 	if (llc_sk(sk)->cmsg_flags)
891 		llc_cmsg_rcv(msg, skb);
892 
893 	if (!(flags & MSG_PEEK)) {
894 		skb_unlink(skb, &sk->sk_receive_queue);
895 		kfree_skb(skb);
896 		*seq = 0;
897 	}
898 
899 	goto out;
900 }
901 
902 /**
903  *	llc_ui_sendmsg - Transmit data provided by the socket user.
904  *	@sock: Socket to transmit data from.
905  *	@msg: Various user related information.
906  *	@len: Length of data to transmit.
907  *
908  *	Transmit data provided by the socket user.
909  *	Returns non-negative upon success, negative otherwise.
910  */
911 static int llc_ui_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
912 {
913 	struct sock *sk = sock->sk;
914 	struct llc_sock *llc = llc_sk(sk);
915 	DECLARE_SOCKADDR(struct sockaddr_llc *, addr, msg->msg_name);
916 	int flags = msg->msg_flags;
917 	int noblock = flags & MSG_DONTWAIT;
918 	struct sk_buff *skb = NULL;
919 	size_t size = 0;
920 	int rc = -EINVAL, copied = 0, hdrlen;
921 
922 	dprintk("%s: sending from %02X to %02X\n", __func__,
923 		llc->laddr.lsap, llc->daddr.lsap);
924 	lock_sock(sk);
925 	if (addr) {
926 		if (msg->msg_namelen < sizeof(*addr))
927 			goto out;
928 	} else {
929 		if (llc_ui_addr_null(&llc->addr))
930 			goto out;
931 		addr = &llc->addr;
932 	}
933 	/* must bind connection to sap if user hasn't done it. */
934 	if (sock_flag(sk, SOCK_ZAPPED)) {
935 		/* bind to sap with null dev, exclusive. */
936 		rc = llc_ui_autobind(sock, addr);
937 		if (rc)
938 			goto out;
939 	}
940 	hdrlen = llc->dev->hard_header_len + llc_ui_header_len(sk, addr);
941 	size = hdrlen + len;
942 	if (size > llc->dev->mtu)
943 		size = llc->dev->mtu;
944 	copied = size - hdrlen;
945 	rc = -EINVAL;
946 	if (copied < 0)
947 		goto out;
948 	release_sock(sk);
949 	skb = sock_alloc_send_skb(sk, size, noblock, &rc);
950 	lock_sock(sk);
951 	if (!skb)
952 		goto out;
953 	skb->dev      = llc->dev;
954 	skb->protocol = llc_proto_type(addr->sllc_arphrd);
955 	skb_reserve(skb, hdrlen);
956 	rc = memcpy_from_msg(skb_put(skb, copied), msg, copied);
957 	if (rc)
958 		goto out;
959 	if (sk->sk_type == SOCK_DGRAM || addr->sllc_ua) {
960 		llc_build_and_send_ui_pkt(llc->sap, skb, addr->sllc_mac,
961 					  addr->sllc_sap);
962 		skb = NULL;
963 		goto out;
964 	}
965 	if (addr->sllc_test) {
966 		llc_build_and_send_test_pkt(llc->sap, skb, addr->sllc_mac,
967 					    addr->sllc_sap);
968 		skb = NULL;
969 		goto out;
970 	}
971 	if (addr->sllc_xid) {
972 		llc_build_and_send_xid_pkt(llc->sap, skb, addr->sllc_mac,
973 					   addr->sllc_sap);
974 		skb = NULL;
975 		goto out;
976 	}
977 	rc = -ENOPROTOOPT;
978 	if (!(sk->sk_type == SOCK_STREAM && !addr->sllc_ua))
979 		goto out;
980 	rc = llc_ui_send_data(sk, skb, noblock);
981 	skb = NULL;
982 out:
983 	kfree_skb(skb);
984 	if (rc)
985 		dprintk("%s: failed sending from %02X to %02X: %d\n",
986 			__func__, llc->laddr.lsap, llc->daddr.lsap, rc);
987 	release_sock(sk);
988 	return rc ? : copied;
989 }
990 
991 /**
992  *	llc_ui_getname - return the address info of a socket
993  *	@sock: Socket to get address of.
994  *	@uaddr: Address structure to return information.
995  *	@peer: Does user want local or remote address information.
996  *
997  *	Return the address information of a socket.
998  */
999 static int llc_ui_getname(struct socket *sock, struct sockaddr *uaddr,
1000 			  int peer)
1001 {
1002 	struct sockaddr_llc sllc;
1003 	struct sock *sk = sock->sk;
1004 	struct llc_sock *llc = llc_sk(sk);
1005 	int rc = -EBADF;
1006 
1007 	memset(&sllc, 0, sizeof(sllc));
1008 	lock_sock(sk);
1009 	if (sock_flag(sk, SOCK_ZAPPED))
1010 		goto out;
1011 	if (peer) {
1012 		rc = -ENOTCONN;
1013 		if (sk->sk_state != TCP_ESTABLISHED)
1014 			goto out;
1015 		if(llc->dev)
1016 			sllc.sllc_arphrd = llc->dev->type;
1017 		sllc.sllc_sap = llc->daddr.lsap;
1018 		memcpy(&sllc.sllc_mac, &llc->daddr.mac, IFHWADDRLEN);
1019 	} else {
1020 		rc = -EINVAL;
1021 		if (!llc->sap)
1022 			goto out;
1023 		sllc.sllc_sap = llc->sap->laddr.lsap;
1024 
1025 		if (llc->dev) {
1026 			sllc.sllc_arphrd = llc->dev->type;
1027 			memcpy(&sllc.sllc_mac, llc->dev->dev_addr,
1028 			       IFHWADDRLEN);
1029 		}
1030 	}
1031 	sllc.sllc_family = AF_LLC;
1032 	memcpy(uaddr, &sllc, sizeof(sllc));
1033 	rc = sizeof(sllc);
1034 out:
1035 	release_sock(sk);
1036 	return rc;
1037 }
1038 
1039 /**
1040  *	llc_ui_ioctl - io controls for PF_LLC
1041  *	@sock: Socket to get/set info
1042  *	@cmd: command
1043  *	@arg: optional argument for cmd
1044  *
1045  *	get/set info on llc sockets
1046  */
1047 static int llc_ui_ioctl(struct socket *sock, unsigned int cmd,
1048 			unsigned long arg)
1049 {
1050 	return -ENOIOCTLCMD;
1051 }
1052 
1053 /**
1054  *	llc_ui_setsockopt - set various connection specific parameters.
1055  *	@sock: Socket to set options on.
1056  *	@level: Socket level user is requesting operations on.
1057  *	@optname: Operation name.
1058  *	@optval: User provided operation data.
1059  *	@optlen: Length of optval.
1060  *
1061  *	Set various connection specific parameters.
1062  */
1063 static int llc_ui_setsockopt(struct socket *sock, int level, int optname,
1064 			     sockptr_t optval, unsigned int optlen)
1065 {
1066 	struct sock *sk = sock->sk;
1067 	struct llc_sock *llc = llc_sk(sk);
1068 	unsigned int opt;
1069 	int rc = -EINVAL;
1070 
1071 	lock_sock(sk);
1072 	if (unlikely(level != SOL_LLC || optlen != sizeof(int)))
1073 		goto out;
1074 	rc = copy_from_sockptr(&opt, optval, sizeof(opt));
1075 	if (rc)
1076 		goto out;
1077 	rc = -EINVAL;
1078 	switch (optname) {
1079 	case LLC_OPT_RETRY:
1080 		if (opt > LLC_OPT_MAX_RETRY)
1081 			goto out;
1082 		llc->n2 = opt;
1083 		break;
1084 	case LLC_OPT_SIZE:
1085 		if (opt > LLC_OPT_MAX_SIZE)
1086 			goto out;
1087 		llc->n1 = opt;
1088 		break;
1089 	case LLC_OPT_ACK_TMR_EXP:
1090 		if (opt > LLC_OPT_MAX_ACK_TMR_EXP)
1091 			goto out;
1092 		llc->ack_timer.expire = opt * HZ;
1093 		break;
1094 	case LLC_OPT_P_TMR_EXP:
1095 		if (opt > LLC_OPT_MAX_P_TMR_EXP)
1096 			goto out;
1097 		llc->pf_cycle_timer.expire = opt * HZ;
1098 		break;
1099 	case LLC_OPT_REJ_TMR_EXP:
1100 		if (opt > LLC_OPT_MAX_REJ_TMR_EXP)
1101 			goto out;
1102 		llc->rej_sent_timer.expire = opt * HZ;
1103 		break;
1104 	case LLC_OPT_BUSY_TMR_EXP:
1105 		if (opt > LLC_OPT_MAX_BUSY_TMR_EXP)
1106 			goto out;
1107 		llc->busy_state_timer.expire = opt * HZ;
1108 		break;
1109 	case LLC_OPT_TX_WIN:
1110 		if (opt > LLC_OPT_MAX_WIN)
1111 			goto out;
1112 		llc->k = opt;
1113 		break;
1114 	case LLC_OPT_RX_WIN:
1115 		if (opt > LLC_OPT_MAX_WIN)
1116 			goto out;
1117 		llc->rw = opt;
1118 		break;
1119 	case LLC_OPT_PKTINFO:
1120 		if (opt)
1121 			llc->cmsg_flags |= LLC_CMSG_PKTINFO;
1122 		else
1123 			llc->cmsg_flags &= ~LLC_CMSG_PKTINFO;
1124 		break;
1125 	default:
1126 		rc = -ENOPROTOOPT;
1127 		goto out;
1128 	}
1129 	rc = 0;
1130 out:
1131 	release_sock(sk);
1132 	return rc;
1133 }
1134 
1135 /**
1136  *	llc_ui_getsockopt - get connection specific socket info
1137  *	@sock: Socket to get information from.
1138  *	@level: Socket level user is requesting operations on.
1139  *	@optname: Operation name.
1140  *	@optval: Variable to return operation data in.
1141  *	@optlen: Length of optval.
1142  *
1143  *	Get connection specific socket information.
1144  */
1145 static int llc_ui_getsockopt(struct socket *sock, int level, int optname,
1146 			     char __user *optval, int __user *optlen)
1147 {
1148 	struct sock *sk = sock->sk;
1149 	struct llc_sock *llc = llc_sk(sk);
1150 	int val = 0, len = 0, rc = -EINVAL;
1151 
1152 	lock_sock(sk);
1153 	if (unlikely(level != SOL_LLC))
1154 		goto out;
1155 	rc = get_user(len, optlen);
1156 	if (rc)
1157 		goto out;
1158 	rc = -EINVAL;
1159 	if (len != sizeof(int))
1160 		goto out;
1161 	switch (optname) {
1162 	case LLC_OPT_RETRY:
1163 		val = llc->n2;					break;
1164 	case LLC_OPT_SIZE:
1165 		val = llc->n1;					break;
1166 	case LLC_OPT_ACK_TMR_EXP:
1167 		val = llc->ack_timer.expire / HZ;		break;
1168 	case LLC_OPT_P_TMR_EXP:
1169 		val = llc->pf_cycle_timer.expire / HZ;		break;
1170 	case LLC_OPT_REJ_TMR_EXP:
1171 		val = llc->rej_sent_timer.expire / HZ;		break;
1172 	case LLC_OPT_BUSY_TMR_EXP:
1173 		val = llc->busy_state_timer.expire / HZ;	break;
1174 	case LLC_OPT_TX_WIN:
1175 		val = llc->k;				break;
1176 	case LLC_OPT_RX_WIN:
1177 		val = llc->rw;				break;
1178 	case LLC_OPT_PKTINFO:
1179 		val = (llc->cmsg_flags & LLC_CMSG_PKTINFO) != 0;
1180 		break;
1181 	default:
1182 		rc = -ENOPROTOOPT;
1183 		goto out;
1184 	}
1185 	rc = 0;
1186 	if (put_user(len, optlen) || copy_to_user(optval, &val, len))
1187 		rc = -EFAULT;
1188 out:
1189 	release_sock(sk);
1190 	return rc;
1191 }
1192 
1193 static const struct net_proto_family llc_ui_family_ops = {
1194 	.family = PF_LLC,
1195 	.create = llc_ui_create,
1196 	.owner	= THIS_MODULE,
1197 };
1198 
1199 static const struct proto_ops llc_ui_ops = {
1200 	.family	     = PF_LLC,
1201 	.owner       = THIS_MODULE,
1202 	.release     = llc_ui_release,
1203 	.bind	     = llc_ui_bind,
1204 	.connect     = llc_ui_connect,
1205 	.socketpair  = sock_no_socketpair,
1206 	.accept      = llc_ui_accept,
1207 	.getname     = llc_ui_getname,
1208 	.poll	     = datagram_poll,
1209 	.ioctl       = llc_ui_ioctl,
1210 	.listen      = llc_ui_listen,
1211 	.shutdown    = llc_ui_shutdown,
1212 	.setsockopt  = llc_ui_setsockopt,
1213 	.getsockopt  = llc_ui_getsockopt,
1214 	.sendmsg     = llc_ui_sendmsg,
1215 	.recvmsg     = llc_ui_recvmsg,
1216 	.mmap	     = sock_no_mmap,
1217 	.sendpage    = sock_no_sendpage,
1218 };
1219 
1220 static const char llc_proc_err_msg[] __initconst =
1221 	KERN_CRIT "LLC: Unable to register the proc_fs entries\n";
1222 static const char llc_sysctl_err_msg[] __initconst =
1223 	KERN_CRIT "LLC: Unable to register the sysctl entries\n";
1224 static const char llc_sock_err_msg[] __initconst =
1225 	KERN_CRIT "LLC: Unable to register the network family\n";
1226 
1227 static int __init llc2_init(void)
1228 {
1229 	int rc = proto_register(&llc_proto, 0);
1230 
1231 	if (rc != 0)
1232 		goto out;
1233 
1234 	llc_build_offset_table();
1235 	llc_station_init();
1236 	llc_ui_sap_last_autoport = LLC_SAP_DYN_START;
1237 	rc = llc_proc_init();
1238 	if (rc != 0) {
1239 		printk(llc_proc_err_msg);
1240 		goto out_station;
1241 	}
1242 	rc = llc_sysctl_init();
1243 	if (rc) {
1244 		printk(llc_sysctl_err_msg);
1245 		goto out_proc;
1246 	}
1247 	rc = sock_register(&llc_ui_family_ops);
1248 	if (rc) {
1249 		printk(llc_sock_err_msg);
1250 		goto out_sysctl;
1251 	}
1252 	llc_add_pack(LLC_DEST_SAP, llc_sap_handler);
1253 	llc_add_pack(LLC_DEST_CONN, llc_conn_handler);
1254 out:
1255 	return rc;
1256 out_sysctl:
1257 	llc_sysctl_exit();
1258 out_proc:
1259 	llc_proc_exit();
1260 out_station:
1261 	llc_station_exit();
1262 	proto_unregister(&llc_proto);
1263 	goto out;
1264 }
1265 
1266 static void __exit llc2_exit(void)
1267 {
1268 	llc_station_exit();
1269 	llc_remove_pack(LLC_DEST_SAP);
1270 	llc_remove_pack(LLC_DEST_CONN);
1271 	sock_unregister(PF_LLC);
1272 	llc_proc_exit();
1273 	llc_sysctl_exit();
1274 	proto_unregister(&llc_proto);
1275 }
1276 
1277 module_init(llc2_init);
1278 module_exit(llc2_exit);
1279 
1280 MODULE_LICENSE("GPL");
1281 MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003");
1282 MODULE_DESCRIPTION("IEEE 802.2 PF_LLC support");
1283 MODULE_ALIAS_NETPROTO(PF_LLC);
1284