1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * af_llc.c - LLC User Interface SAPs
4 * Description:
5 * Functions in this module are implementation of socket based llc
6 * communications for the Linux operating system. Support of llc class
7 * one and class two is provided via SOCK_DGRAM and SOCK_STREAM
8 * respectively.
9 *
10 * An llc2 connection is (mac + sap), only one llc2 sap connection
11 * is allowed per mac. Though one sap may have multiple mac + sap
12 * connections.
13 *
14 * Copyright (c) 2001 by Jay Schulist <jschlst@samba.org>
15 * 2002-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
16 */
17 #include <linux/compiler.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/rtnetlink.h>
21 #include <linux/init.h>
22 #include <linux/slab.h>
23 #include <linux/sched/signal.h>
24 #include <linux/uio.h>
25
26 #include <net/llc.h>
27 #include <net/llc_sap.h>
28 #include <net/llc_pdu.h>
29 #include <net/llc_conn.h>
30 #include <net/tcp_states.h>
31
32 /* remember: uninitialized global data is zeroed because its in .bss */
33 static u16 llc_ui_sap_last_autoport = LLC_SAP_DYN_START;
34 static u16 llc_ui_sap_link_no_max[256];
35 static struct sockaddr_llc llc_ui_addrnull;
36 static const struct proto_ops llc_ui_ops;
37
38 static bool llc_ui_wait_for_conn(struct sock *sk, long timeout);
39 static int llc_ui_wait_for_disc(struct sock *sk, long timeout);
40 static int llc_ui_wait_for_busy_core(struct sock *sk, long timeout);
41
42 #if 0
43 #define dprintk(args...) printk(KERN_DEBUG args)
44 #else
45 #define dprintk(args...) do {} while (0)
46 #endif
47
48 /* Maybe we'll add some more in the future. */
49 #define LLC_CMSG_PKTINFO 1
50
51
52 /**
53 * llc_ui_next_link_no - return the next unused link number for a sap
54 * @sap: Address of sap to get link number from.
55 *
56 * Return the next unused link number for a given sap.
57 */
llc_ui_next_link_no(int sap)58 static inline u16 llc_ui_next_link_no(int sap)
59 {
60 return llc_ui_sap_link_no_max[sap]++;
61 }
62
63 /**
64 * llc_proto_type - return eth protocol for ARP header type
65 * @arphrd: ARP header type.
66 *
67 * Given an ARP header type return the corresponding ethernet protocol.
68 */
llc_proto_type(u16 arphrd)69 static inline __be16 llc_proto_type(u16 arphrd)
70 {
71 return htons(ETH_P_802_2);
72 }
73
74 /**
75 * llc_ui_addr_null - determines if a address structure is null
76 * @addr: Address to test if null.
77 */
llc_ui_addr_null(struct sockaddr_llc * addr)78 static inline u8 llc_ui_addr_null(struct sockaddr_llc *addr)
79 {
80 return !memcmp(addr, &llc_ui_addrnull, sizeof(*addr));
81 }
82
83 /**
84 * llc_ui_header_len - return length of llc header based on operation
85 * @sk: Socket which contains a valid llc socket type.
86 * @addr: Complete sockaddr_llc structure received from the user.
87 *
88 * Provide the length of the llc header depending on what kind of
89 * operation the user would like to perform and the type of socket.
90 * Returns the correct llc header length.
91 */
llc_ui_header_len(struct sock * sk,struct sockaddr_llc * addr)92 static inline u8 llc_ui_header_len(struct sock *sk, struct sockaddr_llc *addr)
93 {
94 u8 rc = LLC_PDU_LEN_U;
95
96 if (addr->sllc_test)
97 rc = LLC_PDU_LEN_U;
98 else if (addr->sllc_xid)
99 /* We need to expand header to sizeof(struct llc_xid_info)
100 * since llc_pdu_init_as_xid_cmd() sets 4,5,6 bytes of LLC header
101 * as XID PDU. In llc_ui_sendmsg() we reserved header size and then
102 * filled all other space with user data. If we won't reserve this
103 * bytes, llc_pdu_init_as_xid_cmd() will overwrite user data
104 */
105 rc = LLC_PDU_LEN_U_XID;
106 else if (sk->sk_type == SOCK_STREAM)
107 rc = LLC_PDU_LEN_I;
108 return rc;
109 }
110
111 /**
112 * llc_ui_send_data - send data via reliable llc2 connection
113 * @sk: Connection the socket is using.
114 * @skb: Data the user wishes to send.
115 * @noblock: can we block waiting for data?
116 *
117 * Send data via reliable llc2 connection.
118 * Returns 0 upon success, non-zero if action did not succeed.
119 *
120 * This function always consumes a reference to the skb.
121 */
llc_ui_send_data(struct sock * sk,struct sk_buff * skb,int noblock)122 static int llc_ui_send_data(struct sock* sk, struct sk_buff *skb, int noblock)
123 {
124 struct llc_sock* llc = llc_sk(sk);
125
126 if (unlikely(llc_data_accept_state(llc->state) ||
127 llc->remote_busy_flag ||
128 llc->p_flag)) {
129 long timeout = sock_sndtimeo(sk, noblock);
130 int rc;
131
132 rc = llc_ui_wait_for_busy_core(sk, timeout);
133 if (rc) {
134 kfree_skb(skb);
135 return rc;
136 }
137 }
138 return llc_build_and_send_pkt(sk, skb);
139 }
140
llc_ui_sk_init(struct socket * sock,struct sock * sk)141 static void llc_ui_sk_init(struct socket *sock, struct sock *sk)
142 {
143 sock_graft(sk, sock);
144 sk->sk_type = sock->type;
145 sock->ops = &llc_ui_ops;
146 }
147
148 static struct proto llc_proto = {
149 .name = "LLC",
150 .owner = THIS_MODULE,
151 .obj_size = sizeof(struct llc_sock),
152 .slab_flags = SLAB_TYPESAFE_BY_RCU,
153 };
154
155 /**
156 * llc_ui_create - alloc and init a new llc_ui socket
157 * @net: network namespace (must be default network)
158 * @sock: Socket to initialize and attach allocated sk to.
159 * @protocol: Unused.
160 * @kern: on behalf of kernel or userspace
161 *
162 * Allocate and initialize a new llc_ui socket, validate the user wants a
163 * socket type we have available.
164 * Returns 0 upon success, negative upon failure.
165 */
llc_ui_create(struct net * net,struct socket * sock,int protocol,int kern)166 static int llc_ui_create(struct net *net, struct socket *sock, int protocol,
167 int kern)
168 {
169 struct sock *sk;
170 int rc = -ESOCKTNOSUPPORT;
171
172 if (!ns_capable(net->user_ns, CAP_NET_RAW))
173 return -EPERM;
174
175 if (!net_eq(net, &init_net))
176 return -EAFNOSUPPORT;
177
178 if (likely(sock->type == SOCK_DGRAM || sock->type == SOCK_STREAM)) {
179 rc = -ENOMEM;
180 sk = llc_sk_alloc(net, PF_LLC, GFP_KERNEL, &llc_proto, kern);
181 if (sk) {
182 rc = 0;
183 llc_ui_sk_init(sock, sk);
184 }
185 }
186 return rc;
187 }
188
189 /**
190 * llc_ui_release - shutdown socket
191 * @sock: Socket to release.
192 *
193 * Shutdown and deallocate an existing socket.
194 */
llc_ui_release(struct socket * sock)195 static int llc_ui_release(struct socket *sock)
196 {
197 struct sock *sk = sock->sk;
198 struct llc_sock *llc;
199
200 if (unlikely(sk == NULL))
201 goto out;
202 sock_hold(sk);
203 lock_sock(sk);
204 llc = llc_sk(sk);
205 dprintk("%s: closing local(%02X) remote(%02X)\n", __func__,
206 llc->laddr.lsap, llc->daddr.lsap);
207 if (!llc_send_disc(sk))
208 llc_ui_wait_for_disc(sk, READ_ONCE(sk->sk_rcvtimeo));
209 if (!sock_flag(sk, SOCK_ZAPPED)) {
210 struct llc_sap *sap = llc->sap;
211
212 /* Hold this for release_sock(), so that llc_backlog_rcv()
213 * could still use it.
214 */
215 llc_sap_hold(sap);
216 llc_sap_remove_socket(llc->sap, sk);
217 release_sock(sk);
218 llc_sap_put(sap);
219 } else {
220 release_sock(sk);
221 }
222 netdev_put(llc->dev, &llc->dev_tracker);
223 sock_put(sk);
224 sock_orphan(sk);
225 sock->sk = NULL;
226 llc_sk_free(sk);
227 out:
228 return 0;
229 }
230
231 /**
232 * llc_ui_autoport - provide dynamically allocate SAP number
233 *
234 * Provide the caller with a dynamically allocated SAP number according
235 * to the rules that are set in this function. Returns: 0, upon failure,
236 * SAP number otherwise.
237 */
llc_ui_autoport(void)238 static int llc_ui_autoport(void)
239 {
240 struct llc_sap *sap;
241 int i, tries = 0;
242
243 while (tries < LLC_SAP_DYN_TRIES) {
244 for (i = llc_ui_sap_last_autoport;
245 i < LLC_SAP_DYN_STOP; i += 2) {
246 sap = llc_sap_find(i);
247 if (!sap) {
248 llc_ui_sap_last_autoport = i + 2;
249 goto out;
250 }
251 llc_sap_put(sap);
252 }
253 llc_ui_sap_last_autoport = LLC_SAP_DYN_START;
254 tries++;
255 }
256 i = 0;
257 out:
258 return i;
259 }
260
261 /**
262 * llc_ui_autobind - automatically bind a socket to a sap
263 * @sock: socket to bind
264 * @addr: address to connect to
265 *
266 * Used by llc_ui_connect and llc_ui_sendmsg when the user hasn't
267 * specifically used llc_ui_bind to bind to an specific address/sap
268 *
269 * Returns: 0 upon success, negative otherwise.
270 */
llc_ui_autobind(struct socket * sock,struct sockaddr_llc * addr)271 static int llc_ui_autobind(struct socket *sock, struct sockaddr_llc *addr)
272 {
273 struct sock *sk = sock->sk;
274 struct llc_sock *llc = llc_sk(sk);
275 struct net_device *dev = NULL;
276 struct llc_sap *sap;
277 int rc = -EINVAL;
278
279 if (!sock_flag(sk, SOCK_ZAPPED))
280 goto out;
281 if (!addr->sllc_arphrd)
282 addr->sllc_arphrd = ARPHRD_ETHER;
283 if (addr->sllc_arphrd != ARPHRD_ETHER)
284 goto out;
285 rc = -ENODEV;
286 if (sk->sk_bound_dev_if) {
287 dev = dev_get_by_index(&init_net, sk->sk_bound_dev_if);
288 if (dev && addr->sllc_arphrd != dev->type) {
289 dev_put(dev);
290 dev = NULL;
291 }
292 } else
293 dev = dev_getfirstbyhwtype(&init_net, addr->sllc_arphrd);
294 if (!dev)
295 goto out;
296 rc = -EUSERS;
297 llc->laddr.lsap = llc_ui_autoport();
298 if (!llc->laddr.lsap)
299 goto out;
300 rc = -EBUSY; /* some other network layer is using the sap */
301 sap = llc_sap_open(llc->laddr.lsap, NULL);
302 if (!sap)
303 goto out;
304
305 /* Note: We do not expect errors from this point. */
306 llc->dev = dev;
307 netdev_tracker_alloc(llc->dev, &llc->dev_tracker, GFP_KERNEL);
308 dev = NULL;
309
310 memcpy(llc->laddr.mac, llc->dev->dev_addr, IFHWADDRLEN);
311 memcpy(&llc->addr, addr, sizeof(llc->addr));
312 /* assign new connection to its SAP */
313 llc_sap_add_socket(sap, sk);
314 sock_reset_flag(sk, SOCK_ZAPPED);
315 llc_sap_put(sap);
316 rc = 0;
317 out:
318 dev_put(dev);
319 return rc;
320 }
321
322 /**
323 * llc_ui_bind - bind a socket to a specific address.
324 * @sock: Socket to bind an address to.
325 * @uaddr: Address the user wants the socket bound to.
326 * @addrlen: Length of the uaddr structure.
327 *
328 * Bind a socket to a specific address. For llc a user is able to bind to
329 * a specific sap only or mac + sap.
330 * If the user desires to bind to a specific mac + sap, it is possible to
331 * have multiple sap connections via multiple macs.
332 * Bind and autobind for that matter must enforce the correct sap usage
333 * otherwise all hell will break loose.
334 * Returns: 0 upon success, negative otherwise.
335 */
llc_ui_bind(struct socket * sock,struct sockaddr_unsized * uaddr,int addrlen)336 static int llc_ui_bind(struct socket *sock, struct sockaddr_unsized *uaddr, int addrlen)
337 {
338 struct sockaddr_llc *addr = (struct sockaddr_llc *)uaddr;
339 struct sock *sk = sock->sk;
340 struct llc_sock *llc = llc_sk(sk);
341 struct net_device *dev = NULL;
342 struct llc_sap *sap;
343 int rc = -EINVAL;
344
345 lock_sock(sk);
346 if (unlikely(!sock_flag(sk, SOCK_ZAPPED) || addrlen != sizeof(*addr)))
347 goto out;
348 rc = -EAFNOSUPPORT;
349 if (!addr->sllc_arphrd)
350 addr->sllc_arphrd = ARPHRD_ETHER;
351 if (unlikely(addr->sllc_family != AF_LLC || addr->sllc_arphrd != ARPHRD_ETHER))
352 goto out;
353 dprintk("%s: binding %02X\n", __func__, addr->sllc_sap);
354 rc = -ENODEV;
355 rcu_read_lock();
356 if (sk->sk_bound_dev_if) {
357 dev = dev_get_by_index_rcu(&init_net, sk->sk_bound_dev_if);
358 if (dev) {
359 if (is_zero_ether_addr(addr->sllc_mac))
360 memcpy(addr->sllc_mac, dev->dev_addr,
361 IFHWADDRLEN);
362 if (addr->sllc_arphrd != dev->type ||
363 !ether_addr_equal(addr->sllc_mac,
364 dev->dev_addr)) {
365 rc = -EINVAL;
366 dev = NULL;
367 }
368 }
369 } else {
370 dev = dev_getbyhwaddr_rcu(&init_net, addr->sllc_arphrd,
371 addr->sllc_mac);
372 }
373 dev_hold(dev);
374 rcu_read_unlock();
375 if (!dev)
376 goto out;
377
378 if (!addr->sllc_sap) {
379 rc = -EUSERS;
380 addr->sllc_sap = llc_ui_autoport();
381 if (!addr->sllc_sap)
382 goto out;
383 }
384 sap = llc_sap_find(addr->sllc_sap);
385 if (!sap) {
386 sap = llc_sap_open(addr->sllc_sap, NULL);
387 rc = -EBUSY; /* some other network layer is using the sap */
388 if (!sap)
389 goto out;
390 } else {
391 struct llc_addr laddr, daddr;
392 struct sock *ask;
393
394 memset(&laddr, 0, sizeof(laddr));
395 memset(&daddr, 0, sizeof(daddr));
396 /*
397 * FIXME: check if the address is multicast,
398 * only SOCK_DGRAM can do this.
399 */
400 memcpy(laddr.mac, addr->sllc_mac, IFHWADDRLEN);
401 laddr.lsap = addr->sllc_sap;
402 rc = -EADDRINUSE; /* mac + sap clash. */
403 ask = llc_lookup_established(sap, &daddr, &laddr, &init_net);
404 if (ask) {
405 sock_put(ask);
406 goto out_put;
407 }
408 }
409
410 /* Note: We do not expect errors from this point. */
411 llc->dev = dev;
412 netdev_tracker_alloc(llc->dev, &llc->dev_tracker, GFP_KERNEL);
413 dev = NULL;
414
415 llc->laddr.lsap = addr->sllc_sap;
416 memcpy(llc->laddr.mac, addr->sllc_mac, IFHWADDRLEN);
417 memcpy(&llc->addr, addr, sizeof(llc->addr));
418 /* assign new connection to its SAP */
419 llc_sap_add_socket(sap, sk);
420 sock_reset_flag(sk, SOCK_ZAPPED);
421 rc = 0;
422 out_put:
423 llc_sap_put(sap);
424 out:
425 dev_put(dev);
426 release_sock(sk);
427 return rc;
428 }
429
430 /**
431 * llc_ui_shutdown - shutdown a connect llc2 socket.
432 * @sock: Socket to shutdown.
433 * @how: What part of the socket to shutdown.
434 *
435 * Shutdown a connected llc2 socket. Currently this function only supports
436 * shutting down both sends and receives (2), we could probably make this
437 * function such that a user can shutdown only half the connection but not
438 * right now.
439 * Returns: 0 upon success, negative otherwise.
440 */
llc_ui_shutdown(struct socket * sock,int how)441 static int llc_ui_shutdown(struct socket *sock, int how)
442 {
443 struct sock *sk = sock->sk;
444 int rc = -ENOTCONN;
445
446 lock_sock(sk);
447 if (unlikely(sk->sk_state != TCP_ESTABLISHED))
448 goto out;
449 rc = -EINVAL;
450 if (how != 2)
451 goto out;
452 rc = llc_send_disc(sk);
453 if (!rc)
454 rc = llc_ui_wait_for_disc(sk, READ_ONCE(sk->sk_rcvtimeo));
455 /* Wake up anyone sleeping in poll */
456 sk->sk_state_change(sk);
457 out:
458 release_sock(sk);
459 return rc;
460 }
461
462 /**
463 * llc_ui_connect - Connect to a remote llc2 mac + sap.
464 * @sock: Socket which will be connected to the remote destination.
465 * @uaddr: Remote and possibly the local address of the new connection.
466 * @addrlen: Size of uaddr structure.
467 * @flags: Operational flags specified by the user.
468 *
469 * Connect to a remote llc2 mac + sap. The caller must specify the
470 * destination mac and address to connect to. If the user hasn't previously
471 * called bind(2) with a smac the address of the first interface of the
472 * specified arp type will be used.
473 * This function will autobind if user did not previously call bind.
474 * Returns: 0 upon success, negative otherwise.
475 */
llc_ui_connect(struct socket * sock,struct sockaddr_unsized * uaddr,int addrlen,int flags)476 static int llc_ui_connect(struct socket *sock, struct sockaddr_unsized *uaddr,
477 int addrlen, int flags)
478 {
479 struct sock *sk = sock->sk;
480 struct llc_sock *llc = llc_sk(sk);
481 struct sockaddr_llc *addr = (struct sockaddr_llc *)uaddr;
482 int rc = -EINVAL;
483
484 lock_sock(sk);
485 if (unlikely(addrlen != sizeof(*addr)))
486 goto out;
487 rc = -EAFNOSUPPORT;
488 if (unlikely(addr->sllc_family != AF_LLC))
489 goto out;
490 if (unlikely(sk->sk_type != SOCK_STREAM))
491 goto out;
492 rc = -EALREADY;
493 if (unlikely(sock->state == SS_CONNECTING))
494 goto out;
495 /* bind connection to sap if user hasn't done it. */
496 if (sock_flag(sk, SOCK_ZAPPED)) {
497 /* bind to sap with null dev, exclusive */
498 rc = llc_ui_autobind(sock, addr);
499 if (rc)
500 goto out;
501 }
502 llc->daddr.lsap = addr->sllc_sap;
503 memcpy(llc->daddr.mac, addr->sllc_mac, IFHWADDRLEN);
504 sock->state = SS_CONNECTING;
505 sk->sk_state = TCP_SYN_SENT;
506 llc->link = llc_ui_next_link_no(llc->sap->laddr.lsap);
507 rc = llc_establish_connection(sk, llc->dev->dev_addr,
508 addr->sllc_mac, addr->sllc_sap);
509 if (rc) {
510 dprintk("%s: llc_ui_send_conn failed :-(\n", __func__);
511 sock->state = SS_UNCONNECTED;
512 sk->sk_state = TCP_CLOSE;
513 goto out;
514 }
515
516 if (sk->sk_state == TCP_SYN_SENT) {
517 const long timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
518
519 if (!timeo || !llc_ui_wait_for_conn(sk, timeo)) {
520 rc = -EINPROGRESS;
521 goto out;
522 }
523
524 rc = sock_intr_errno(timeo);
525 if (signal_pending(current))
526 goto out;
527 }
528
529 if (sk->sk_state == TCP_CLOSE)
530 goto sock_error;
531
532 sock->state = SS_CONNECTED;
533 rc = 0;
534 out:
535 release_sock(sk);
536 return rc;
537 sock_error:
538 rc = sock_error(sk) ? : -ECONNABORTED;
539 sock->state = SS_UNCONNECTED;
540 goto out;
541 }
542
543 /**
544 * llc_ui_listen - allow a normal socket to accept incoming connections
545 * @sock: Socket to allow incoming connections on.
546 * @backlog: Number of connections to queue.
547 *
548 * Allow a normal socket to accept incoming connections.
549 * Returns 0 upon success, negative otherwise.
550 */
llc_ui_listen(struct socket * sock,int backlog)551 static int llc_ui_listen(struct socket *sock, int backlog)
552 {
553 struct sock *sk = sock->sk;
554 int rc = -EINVAL;
555
556 lock_sock(sk);
557 if (unlikely(sock->state != SS_UNCONNECTED))
558 goto out;
559 rc = -EOPNOTSUPP;
560 if (unlikely(sk->sk_type != SOCK_STREAM))
561 goto out;
562 rc = -EAGAIN;
563 if (sock_flag(sk, SOCK_ZAPPED))
564 goto out;
565 rc = 0;
566 if (!(unsigned int)backlog) /* BSDism */
567 backlog = 1;
568 sk->sk_max_ack_backlog = backlog;
569 if (sk->sk_state != TCP_LISTEN) {
570 sk->sk_ack_backlog = 0;
571 sk->sk_state = TCP_LISTEN;
572 }
573 sk->sk_socket->flags |= __SO_ACCEPTCON;
574 out:
575 release_sock(sk);
576 return rc;
577 }
578
llc_ui_wait_for_disc(struct sock * sk,long timeout)579 static int llc_ui_wait_for_disc(struct sock *sk, long timeout)
580 {
581 DEFINE_WAIT_FUNC(wait, woken_wake_function);
582 int rc = 0;
583
584 add_wait_queue(sk_sleep(sk), &wait);
585 while (1) {
586 if (sk_wait_event(sk, &timeout,
587 READ_ONCE(sk->sk_state) == TCP_CLOSE, &wait))
588 break;
589 rc = -ERESTARTSYS;
590 if (signal_pending(current))
591 break;
592 rc = -EAGAIN;
593 if (!timeout)
594 break;
595 rc = 0;
596 }
597 remove_wait_queue(sk_sleep(sk), &wait);
598 return rc;
599 }
600
llc_ui_wait_for_conn(struct sock * sk,long timeout)601 static bool llc_ui_wait_for_conn(struct sock *sk, long timeout)
602 {
603 DEFINE_WAIT_FUNC(wait, woken_wake_function);
604
605 add_wait_queue(sk_sleep(sk), &wait);
606 while (1) {
607 if (sk_wait_event(sk, &timeout,
608 READ_ONCE(sk->sk_state) != TCP_SYN_SENT, &wait))
609 break;
610 if (signal_pending(current) || !timeout)
611 break;
612 }
613 remove_wait_queue(sk_sleep(sk), &wait);
614 return timeout;
615 }
616
llc_ui_wait_for_busy_core(struct sock * sk,long timeout)617 static int llc_ui_wait_for_busy_core(struct sock *sk, long timeout)
618 {
619 DEFINE_WAIT_FUNC(wait, woken_wake_function);
620 struct llc_sock *llc = llc_sk(sk);
621 int rc;
622
623 add_wait_queue(sk_sleep(sk), &wait);
624 while (1) {
625 rc = 0;
626 if (sk_wait_event(sk, &timeout,
627 (READ_ONCE(sk->sk_shutdown) & RCV_SHUTDOWN) ||
628 (!llc_data_accept_state(llc->state) &&
629 !llc->remote_busy_flag &&
630 !llc->p_flag), &wait))
631 break;
632 rc = -ERESTARTSYS;
633 if (signal_pending(current))
634 break;
635 rc = -EAGAIN;
636 if (!timeout)
637 break;
638 }
639 remove_wait_queue(sk_sleep(sk), &wait);
640 return rc;
641 }
642
llc_wait_data(struct sock * sk,long timeo)643 static int llc_wait_data(struct sock *sk, long timeo)
644 {
645 int rc;
646
647 while (1) {
648 /*
649 * POSIX 1003.1g mandates this order.
650 */
651 rc = sock_error(sk);
652 if (rc)
653 break;
654 rc = 0;
655 if (sk->sk_shutdown & RCV_SHUTDOWN)
656 break;
657 rc = -EAGAIN;
658 if (!timeo)
659 break;
660 rc = sock_intr_errno(timeo);
661 if (signal_pending(current))
662 break;
663 rc = 0;
664 if (sk_wait_data(sk, &timeo, NULL))
665 break;
666 }
667 return rc;
668 }
669
llc_cmsg_rcv(struct msghdr * msg,struct sk_buff * skb)670 static void llc_cmsg_rcv(struct msghdr *msg, struct sk_buff *skb)
671 {
672 struct llc_sock *llc = llc_sk(skb->sk);
673
674 if (llc->cmsg_flags & LLC_CMSG_PKTINFO) {
675 struct llc_pktinfo info;
676
677 memset(&info, 0, sizeof(info));
678 info.lpi_ifindex = llc_sk(skb->sk)->dev->ifindex;
679 llc_pdu_decode_dsap(skb, &info.lpi_sap);
680 llc_pdu_decode_da(skb, info.lpi_mac);
681 put_cmsg(msg, SOL_LLC, LLC_OPT_PKTINFO, sizeof(info), &info);
682 }
683 }
684
685 /**
686 * llc_ui_accept - accept a new incoming connection.
687 * @sock: Socket which connections arrive on.
688 * @newsock: Socket to move incoming connection to.
689 * @arg: User specified arguments
690 *
691 * Accept a new incoming connection.
692 * Returns 0 upon success, negative otherwise.
693 */
llc_ui_accept(struct socket * sock,struct socket * newsock,struct proto_accept_arg * arg)694 static int llc_ui_accept(struct socket *sock, struct socket *newsock,
695 struct proto_accept_arg *arg)
696 {
697 struct sock *sk = sock->sk, *newsk;
698 struct llc_sock *llc, *newllc;
699 struct sk_buff *skb;
700 int rc = -EOPNOTSUPP;
701
702 dprintk("%s: accepting on %02X\n", __func__,
703 llc_sk(sk)->laddr.lsap);
704 lock_sock(sk);
705 if (unlikely(sk->sk_type != SOCK_STREAM))
706 goto out;
707 rc = -EINVAL;
708 if (unlikely(sock->state != SS_UNCONNECTED ||
709 sk->sk_state != TCP_LISTEN))
710 goto out;
711 /* wait for a connection to arrive. */
712 if (skb_queue_empty(&sk->sk_receive_queue)) {
713 rc = llc_wait_data(sk, READ_ONCE(sk->sk_rcvtimeo));
714 if (rc)
715 goto out;
716 }
717 dprintk("%s: got a new connection on %02X\n", __func__,
718 llc_sk(sk)->laddr.lsap);
719 skb = skb_dequeue(&sk->sk_receive_queue);
720 rc = -EINVAL;
721 if (!skb->sk)
722 goto frees;
723 rc = 0;
724 newsk = skb->sk;
725 /* attach connection to a new socket. */
726 llc_ui_sk_init(newsock, newsk);
727 sock_reset_flag(newsk, SOCK_ZAPPED);
728 newsk->sk_state = TCP_ESTABLISHED;
729 newsock->state = SS_CONNECTED;
730 llc = llc_sk(sk);
731 newllc = llc_sk(newsk);
732 memcpy(&newllc->addr, &llc->addr, sizeof(newllc->addr));
733 newllc->link = llc_ui_next_link_no(newllc->laddr.lsap);
734
735 /* put original socket back into a clean listen state. */
736 sk->sk_state = TCP_LISTEN;
737 sk_acceptq_removed(sk);
738 dprintk("%s: ok success on %02X, client on %02X\n", __func__,
739 llc_sk(sk)->addr.sllc_sap, newllc->daddr.lsap);
740 frees:
741 kfree_skb(skb);
742 out:
743 release_sock(sk);
744 return rc;
745 }
746
747 /**
748 * llc_ui_recvmsg - copy received data to the socket user.
749 * @sock: Socket to copy data from.
750 * @msg: Various user space related information.
751 * @len: Size of user buffer.
752 * @flags: User specified flags.
753 *
754 * Copy received data to the socket user.
755 * Returns non-negative upon success, negative otherwise.
756 */
llc_ui_recvmsg(struct socket * sock,struct msghdr * msg,size_t len,int flags)757 static int llc_ui_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
758 int flags)
759 {
760 DECLARE_SOCKADDR(struct sockaddr_llc *, uaddr, msg->msg_name);
761 const int nonblock = flags & MSG_DONTWAIT;
762 struct sk_buff *skb = NULL;
763 struct sock *sk = sock->sk;
764 struct llc_sock *llc = llc_sk(sk);
765 size_t copied = 0;
766 u32 peek_seq = 0;
767 u32 *seq, skb_len;
768 unsigned long used;
769 int target; /* Read at least this many bytes */
770 long timeo;
771
772 lock_sock(sk);
773 copied = -ENOTCONN;
774 if (unlikely(sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_LISTEN))
775 goto out;
776
777 timeo = sock_rcvtimeo(sk, nonblock);
778
779 seq = &llc->copied_seq;
780 if (flags & MSG_PEEK) {
781 peek_seq = llc->copied_seq;
782 seq = &peek_seq;
783 }
784
785 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
786 copied = 0;
787
788 do {
789 u32 offset;
790
791 /*
792 * We need to check signals first, to get correct SIGURG
793 * handling. FIXME: Need to check this doesn't impact 1003.1g
794 * and move it down to the bottom of the loop
795 */
796 if (signal_pending(current)) {
797 if (copied)
798 break;
799 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
800 break;
801 }
802
803 /* Next get a buffer. */
804
805 skb = skb_peek(&sk->sk_receive_queue);
806 if (skb) {
807 offset = *seq;
808 goto found_ok_skb;
809 }
810 /* Well, if we have backlog, try to process it now yet. */
811
812 if (copied >= target && !READ_ONCE(sk->sk_backlog.tail))
813 break;
814
815 if (copied) {
816 if (sk->sk_err ||
817 sk->sk_state == TCP_CLOSE ||
818 (sk->sk_shutdown & RCV_SHUTDOWN) ||
819 !timeo ||
820 (flags & MSG_PEEK))
821 break;
822 } else {
823 if (sock_flag(sk, SOCK_DONE))
824 break;
825
826 if (sk->sk_err) {
827 copied = sock_error(sk);
828 break;
829 }
830 if (sk->sk_shutdown & RCV_SHUTDOWN)
831 break;
832
833 if (sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_CLOSE) {
834 if (!sock_flag(sk, SOCK_DONE)) {
835 /*
836 * This occurs when user tries to read
837 * from never connected socket.
838 */
839 copied = -ENOTCONN;
840 break;
841 }
842 break;
843 }
844 if (!timeo) {
845 copied = -EAGAIN;
846 break;
847 }
848 }
849
850 if (copied >= target) { /* Do not sleep, just process backlog. */
851 release_sock(sk);
852 lock_sock(sk);
853 } else
854 sk_wait_data(sk, &timeo, NULL);
855
856 if ((flags & MSG_PEEK) && peek_seq != llc->copied_seq) {
857 net_dbg_ratelimited("LLC(%s:%d): Application bug, race in MSG_PEEK\n",
858 current->comm,
859 task_pid_nr(current));
860 peek_seq = llc->copied_seq;
861 }
862 continue;
863 found_ok_skb:
864 skb_len = skb->len;
865 /* Ok so how much can we use? */
866 used = skb->len - offset;
867 if (len < used)
868 used = len;
869
870 if (!(flags & MSG_TRUNC)) {
871 int rc = skb_copy_datagram_msg(skb, offset, msg, used);
872 if (rc) {
873 /* Exception. Bailout! */
874 if (!copied)
875 copied = -EFAULT;
876 break;
877 }
878 }
879
880 *seq += used;
881 copied += used;
882 len -= used;
883
884 /* For non stream protcols we get one packet per recvmsg call */
885 if (sk->sk_type != SOCK_STREAM)
886 goto copy_uaddr;
887
888 /* Partial read */
889 if (used + offset < skb_len)
890 continue;
891
892 if (!(flags & MSG_PEEK)) {
893 skb_unlink(skb, &sk->sk_receive_queue);
894 kfree_skb(skb);
895 *seq = 0;
896 }
897 } while (len > 0);
898
899 out:
900 release_sock(sk);
901 return copied;
902 copy_uaddr:
903 if (uaddr != NULL && skb != NULL) {
904 memcpy(uaddr, llc_ui_skb_cb(skb), sizeof(*uaddr));
905 msg->msg_namelen = sizeof(*uaddr);
906 }
907 if (llc_sk(sk)->cmsg_flags)
908 llc_cmsg_rcv(msg, skb);
909
910 if (!(flags & MSG_PEEK)) {
911 skb_unlink(skb, &sk->sk_receive_queue);
912 kfree_skb(skb);
913 *seq = 0;
914 }
915
916 goto out;
917 }
918
919 /**
920 * llc_ui_sendmsg - Transmit data provided by the socket user.
921 * @sock: Socket to transmit data from.
922 * @msg: Various user related information.
923 * @len: Length of data to transmit.
924 *
925 * Transmit data provided by the socket user.
926 * Returns non-negative upon success, negative otherwise.
927 */
llc_ui_sendmsg(struct socket * sock,struct msghdr * msg,size_t len)928 static int llc_ui_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
929 {
930 DECLARE_SOCKADDR(struct sockaddr_llc *, addr, msg->msg_name);
931 struct sock *sk = sock->sk;
932 struct llc_sock *llc = llc_sk(sk);
933 int flags = msg->msg_flags;
934 int noblock = flags & MSG_DONTWAIT;
935 int rc = -EINVAL, copied = 0, hdrlen, hh_len;
936 struct sk_buff *skb = NULL;
937 struct net_device *dev;
938 size_t size = 0;
939
940 dprintk("%s: sending from %02X to %02X\n", __func__,
941 llc->laddr.lsap, llc->daddr.lsap);
942 lock_sock(sk);
943 if (addr) {
944 if (msg->msg_namelen < sizeof(*addr))
945 goto out;
946 } else {
947 if (llc_ui_addr_null(&llc->addr))
948 goto out;
949 addr = &llc->addr;
950 }
951 /* must bind connection to sap if user hasn't done it. */
952 if (sock_flag(sk, SOCK_ZAPPED)) {
953 /* bind to sap with null dev, exclusive. */
954 rc = llc_ui_autobind(sock, addr);
955 if (rc)
956 goto out;
957 }
958 dev = llc->dev;
959 hh_len = LL_RESERVED_SPACE(dev);
960 hdrlen = llc_ui_header_len(sk, addr);
961 size = hdrlen + len;
962 size = min_t(size_t, size, READ_ONCE(dev->mtu));
963 copied = size - hdrlen;
964 rc = -EINVAL;
965 if (copied < 0)
966 goto out;
967 release_sock(sk);
968 skb = sock_alloc_send_skb(sk, hh_len + size, noblock, &rc);
969 lock_sock(sk);
970 if (!skb)
971 goto out;
972 if (sock_flag(sk, SOCK_ZAPPED) ||
973 llc->dev != dev ||
974 hdrlen != llc_ui_header_len(sk, addr) ||
975 hh_len != LL_RESERVED_SPACE(dev) ||
976 size > READ_ONCE(dev->mtu))
977 goto out;
978 skb->dev = dev;
979 skb->protocol = llc_proto_type(addr->sllc_arphrd);
980 skb_reserve(skb, hh_len + hdrlen);
981 rc = memcpy_from_msg(skb_put(skb, copied), msg, copied);
982 if (rc)
983 goto out;
984 if (sk->sk_type == SOCK_DGRAM || addr->sllc_ua) {
985 llc_build_and_send_ui_pkt(llc->sap, skb, addr->sllc_mac,
986 addr->sllc_sap);
987 skb = NULL;
988 goto out;
989 }
990 if (addr->sllc_test) {
991 llc_build_and_send_test_pkt(llc->sap, skb, addr->sllc_mac,
992 addr->sllc_sap);
993 skb = NULL;
994 goto out;
995 }
996 if (addr->sllc_xid) {
997 llc_build_and_send_xid_pkt(llc->sap, skb, addr->sllc_mac,
998 addr->sllc_sap);
999 skb = NULL;
1000 goto out;
1001 }
1002 rc = -ENOPROTOOPT;
1003 if (!(sk->sk_type == SOCK_STREAM && !addr->sllc_ua))
1004 goto out;
1005 rc = llc_ui_send_data(sk, skb, noblock);
1006 skb = NULL;
1007 out:
1008 kfree_skb(skb);
1009 if (rc)
1010 dprintk("%s: failed sending from %02X to %02X: %d\n",
1011 __func__, llc->laddr.lsap, llc->daddr.lsap, rc);
1012 release_sock(sk);
1013 return rc ? : copied;
1014 }
1015
1016 /**
1017 * llc_ui_getname - return the address info of a socket
1018 * @sock: Socket to get address of.
1019 * @uaddr: Address structure to return information.
1020 * @peer: Does user want local or remote address information.
1021 *
1022 * Return the address information of a socket.
1023 */
llc_ui_getname(struct socket * sock,struct sockaddr * uaddr,int peer)1024 static int llc_ui_getname(struct socket *sock, struct sockaddr *uaddr,
1025 int peer)
1026 {
1027 struct sockaddr_llc sllc;
1028 struct sock *sk = sock->sk;
1029 struct llc_sock *llc = llc_sk(sk);
1030 int rc = -EBADF;
1031
1032 memset(&sllc, 0, sizeof(sllc));
1033 lock_sock(sk);
1034 if (sock_flag(sk, SOCK_ZAPPED))
1035 goto out;
1036 if (peer) {
1037 rc = -ENOTCONN;
1038 if (sk->sk_state != TCP_ESTABLISHED)
1039 goto out;
1040 if(llc->dev)
1041 sllc.sllc_arphrd = llc->dev->type;
1042 sllc.sllc_sap = llc->daddr.lsap;
1043 memcpy(&sllc.sllc_mac, &llc->daddr.mac, IFHWADDRLEN);
1044 } else {
1045 rc = -EINVAL;
1046 if (!llc->sap)
1047 goto out;
1048 sllc.sllc_sap = llc->sap->laddr.lsap;
1049
1050 if (llc->dev) {
1051 sllc.sllc_arphrd = llc->dev->type;
1052 memcpy(&sllc.sllc_mac, llc->dev->dev_addr,
1053 IFHWADDRLEN);
1054 }
1055 }
1056 sllc.sllc_family = AF_LLC;
1057 memcpy(uaddr, &sllc, sizeof(sllc));
1058 rc = sizeof(sllc);
1059 out:
1060 release_sock(sk);
1061 return rc;
1062 }
1063
1064 /**
1065 * llc_ui_ioctl - io controls for PF_LLC
1066 * @sock: Socket to get/set info
1067 * @cmd: command
1068 * @arg: optional argument for cmd
1069 *
1070 * get/set info on llc sockets
1071 */
llc_ui_ioctl(struct socket * sock,unsigned int cmd,unsigned long arg)1072 static int llc_ui_ioctl(struct socket *sock, unsigned int cmd,
1073 unsigned long arg)
1074 {
1075 return -ENOIOCTLCMD;
1076 }
1077
1078 /**
1079 * llc_ui_setsockopt - set various connection specific parameters.
1080 * @sock: Socket to set options on.
1081 * @level: Socket level user is requesting operations on.
1082 * @optname: Operation name.
1083 * @optval: User provided operation data.
1084 * @optlen: Length of optval.
1085 *
1086 * Set various connection specific parameters.
1087 */
llc_ui_setsockopt(struct socket * sock,int level,int optname,sockptr_t optval,unsigned int optlen)1088 static int llc_ui_setsockopt(struct socket *sock, int level, int optname,
1089 sockptr_t optval, unsigned int optlen)
1090 {
1091 struct sock *sk = sock->sk;
1092 struct llc_sock *llc = llc_sk(sk);
1093 unsigned int opt;
1094 int rc = -EINVAL;
1095
1096 lock_sock(sk);
1097 if (unlikely(level != SOL_LLC || optlen != sizeof(int)))
1098 goto out;
1099 rc = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen);
1100 if (rc)
1101 goto out;
1102 rc = -EINVAL;
1103 switch (optname) {
1104 case LLC_OPT_RETRY:
1105 if (opt > LLC_OPT_MAX_RETRY)
1106 goto out;
1107 llc->n2 = opt;
1108 break;
1109 case LLC_OPT_SIZE:
1110 if (opt > LLC_OPT_MAX_SIZE)
1111 goto out;
1112 llc->n1 = opt;
1113 break;
1114 case LLC_OPT_ACK_TMR_EXP:
1115 if (opt > LLC_OPT_MAX_ACK_TMR_EXP)
1116 goto out;
1117 llc->ack_timer.expire = opt * HZ;
1118 break;
1119 case LLC_OPT_P_TMR_EXP:
1120 if (opt > LLC_OPT_MAX_P_TMR_EXP)
1121 goto out;
1122 llc->pf_cycle_timer.expire = opt * HZ;
1123 break;
1124 case LLC_OPT_REJ_TMR_EXP:
1125 if (opt > LLC_OPT_MAX_REJ_TMR_EXP)
1126 goto out;
1127 llc->rej_sent_timer.expire = opt * HZ;
1128 break;
1129 case LLC_OPT_BUSY_TMR_EXP:
1130 if (opt > LLC_OPT_MAX_BUSY_TMR_EXP)
1131 goto out;
1132 llc->busy_state_timer.expire = opt * HZ;
1133 break;
1134 case LLC_OPT_TX_WIN:
1135 if (opt > LLC_OPT_MAX_WIN)
1136 goto out;
1137 llc->k = opt;
1138 break;
1139 case LLC_OPT_RX_WIN:
1140 if (opt > LLC_OPT_MAX_WIN)
1141 goto out;
1142 llc->rw = opt;
1143 break;
1144 case LLC_OPT_PKTINFO:
1145 if (opt)
1146 llc->cmsg_flags |= LLC_CMSG_PKTINFO;
1147 else
1148 llc->cmsg_flags &= ~LLC_CMSG_PKTINFO;
1149 break;
1150 default:
1151 rc = -ENOPROTOOPT;
1152 goto out;
1153 }
1154 rc = 0;
1155 out:
1156 release_sock(sk);
1157 return rc;
1158 }
1159
1160 /**
1161 * llc_ui_getsockopt - get connection specific socket info
1162 * @sock: Socket to get information from.
1163 * @level: Socket level user is requesting operations on.
1164 * @optname: Operation name.
1165 * @opt: sockopt context with iterator and length for returning data.
1166 *
1167 * Get connection specific socket information.
1168 */
llc_ui_getsockopt(struct socket * sock,int level,int optname,sockopt_t * opt)1169 static int llc_ui_getsockopt(struct socket *sock, int level, int optname,
1170 sockopt_t *opt)
1171 {
1172 struct sock *sk = sock->sk;
1173 struct llc_sock *llc = llc_sk(sk);
1174 int val = 0, len, rc = -EINVAL;
1175
1176 lock_sock(sk);
1177 if (unlikely(level != SOL_LLC))
1178 goto out;
1179 len = opt->optlen;
1180 if (len != sizeof(int))
1181 goto out;
1182 switch (optname) {
1183 case LLC_OPT_RETRY:
1184 val = llc->n2; break;
1185 case LLC_OPT_SIZE:
1186 val = llc->n1; break;
1187 case LLC_OPT_ACK_TMR_EXP:
1188 val = llc->ack_timer.expire / HZ; break;
1189 case LLC_OPT_P_TMR_EXP:
1190 val = llc->pf_cycle_timer.expire / HZ; break;
1191 case LLC_OPT_REJ_TMR_EXP:
1192 val = llc->rej_sent_timer.expire / HZ; break;
1193 case LLC_OPT_BUSY_TMR_EXP:
1194 val = llc->busy_state_timer.expire / HZ; break;
1195 case LLC_OPT_TX_WIN:
1196 val = llc->k; break;
1197 case LLC_OPT_RX_WIN:
1198 val = llc->rw; break;
1199 case LLC_OPT_PKTINFO:
1200 val = (llc->cmsg_flags & LLC_CMSG_PKTINFO) != 0;
1201 break;
1202 default:
1203 rc = -ENOPROTOOPT;
1204 goto out;
1205 }
1206 rc = 0;
1207 opt->optlen = len;
1208 if (copy_to_iter(&val, len, &opt->iter_out) != len)
1209 rc = -EFAULT;
1210 out:
1211 release_sock(sk);
1212 return rc;
1213 }
1214
1215 static const struct net_proto_family llc_ui_family_ops = {
1216 .family = PF_LLC,
1217 .create = llc_ui_create,
1218 .owner = THIS_MODULE,
1219 };
1220
1221 static const struct proto_ops llc_ui_ops = {
1222 .family = PF_LLC,
1223 .owner = THIS_MODULE,
1224 .release = llc_ui_release,
1225 .bind = llc_ui_bind,
1226 .connect = llc_ui_connect,
1227 .socketpair = sock_no_socketpair,
1228 .accept = llc_ui_accept,
1229 .getname = llc_ui_getname,
1230 .poll = datagram_poll,
1231 .ioctl = llc_ui_ioctl,
1232 .listen = llc_ui_listen,
1233 .shutdown = llc_ui_shutdown,
1234 .setsockopt = llc_ui_setsockopt,
1235 .getsockopt_iter = llc_ui_getsockopt,
1236 .sendmsg = llc_ui_sendmsg,
1237 .recvmsg = llc_ui_recvmsg,
1238 .mmap = sock_no_mmap,
1239 };
1240
1241 static const char llc_proc_err_msg[] __initconst =
1242 KERN_CRIT "LLC: Unable to register the proc_fs entries\n";
1243 static const char llc_sysctl_err_msg[] __initconst =
1244 KERN_CRIT "LLC: Unable to register the sysctl entries\n";
1245 static const char llc_sock_err_msg[] __initconst =
1246 KERN_CRIT "LLC: Unable to register the network family\n";
1247
llc2_init(void)1248 static int __init llc2_init(void)
1249 {
1250 int rc = proto_register(&llc_proto, 0);
1251
1252 if (rc != 0)
1253 goto out;
1254
1255 llc_build_offset_table();
1256 llc_station_init();
1257 llc_ui_sap_last_autoport = LLC_SAP_DYN_START;
1258 rc = llc_proc_init();
1259 if (rc != 0) {
1260 printk(llc_proc_err_msg);
1261 goto out_station;
1262 }
1263 rc = llc_sysctl_init();
1264 if (rc) {
1265 printk(llc_sysctl_err_msg);
1266 goto out_proc;
1267 }
1268 rc = sock_register(&llc_ui_family_ops);
1269 if (rc) {
1270 printk(llc_sock_err_msg);
1271 goto out_sysctl;
1272 }
1273 llc_add_pack(LLC_DEST_SAP, llc_sap_handler);
1274 llc_add_pack(LLC_DEST_CONN, llc_conn_handler);
1275 out:
1276 return rc;
1277 out_sysctl:
1278 llc_sysctl_exit();
1279 out_proc:
1280 llc_proc_exit();
1281 out_station:
1282 llc_station_exit();
1283 proto_unregister(&llc_proto);
1284 goto out;
1285 }
1286
llc2_exit(void)1287 static void __exit llc2_exit(void)
1288 {
1289 llc_station_exit();
1290 llc_remove_pack(LLC_DEST_SAP);
1291 llc_remove_pack(LLC_DEST_CONN);
1292 sock_unregister(PF_LLC);
1293 llc_proc_exit();
1294 llc_sysctl_exit();
1295 proto_unregister(&llc_proto);
1296 }
1297
1298 module_init(llc2_init);
1299 module_exit(llc2_exit);
1300
1301 MODULE_LICENSE("GPL");
1302 MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003");
1303 MODULE_DESCRIPTION("IEEE 802.2 PF_LLC support");
1304 MODULE_ALIAS_NETPROTO(PF_LLC);
1305