xref: /openbmc/linux/net/iucv/af_iucv.c (revision b8bb76713ec50df2f11efee386e16f93d51e1076)
1 /*
2  *  linux/net/iucv/af_iucv.c
3  *
4  *  IUCV protocol stack for Linux on zSeries
5  *
6  *  Copyright 2006 IBM Corporation
7  *
8  *  Author(s):	Jennifer Hunt <jenhunt@us.ibm.com>
9  */
10 
11 #define KMSG_COMPONENT "af_iucv"
12 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
13 
14 #include <linux/module.h>
15 #include <linux/types.h>
16 #include <linux/list.h>
17 #include <linux/errno.h>
18 #include <linux/kernel.h>
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <linux/skbuff.h>
22 #include <linux/init.h>
23 #include <linux/poll.h>
24 #include <net/sock.h>
25 #include <asm/ebcdic.h>
26 #include <asm/cpcmd.h>
27 #include <linux/kmod.h>
28 
29 #include <net/iucv/iucv.h>
30 #include <net/iucv/af_iucv.h>
31 
32 #define CONFIG_IUCV_SOCK_DEBUG 1
33 
34 #define IPRMDATA 0x80
35 #define VERSION "1.0"
36 
37 static char iucv_userid[80];
38 
39 static struct proto_ops iucv_sock_ops;
40 
41 static struct proto iucv_proto = {
42 	.name		= "AF_IUCV",
43 	.owner		= THIS_MODULE,
44 	.obj_size	= sizeof(struct iucv_sock),
45 };
46 
47 static void iucv_sock_kill(struct sock *sk);
48 static void iucv_sock_close(struct sock *sk);
49 
50 /* Call Back functions */
51 static void iucv_callback_rx(struct iucv_path *, struct iucv_message *);
52 static void iucv_callback_txdone(struct iucv_path *, struct iucv_message *);
53 static void iucv_callback_connack(struct iucv_path *, u8 ipuser[16]);
54 static int iucv_callback_connreq(struct iucv_path *, u8 ipvmid[8],
55 				 u8 ipuser[16]);
56 static void iucv_callback_connrej(struct iucv_path *, u8 ipuser[16]);
57 
58 static struct iucv_sock_list iucv_sk_list = {
59 	.lock = __RW_LOCK_UNLOCKED(iucv_sk_list.lock),
60 	.autobind_name = ATOMIC_INIT(0)
61 };
62 
63 static struct iucv_handler af_iucv_handler = {
64 	.path_pending	  = iucv_callback_connreq,
65 	.path_complete	  = iucv_callback_connack,
66 	.path_severed	  = iucv_callback_connrej,
67 	.message_pending  = iucv_callback_rx,
68 	.message_complete = iucv_callback_txdone
69 };
70 
71 static inline void high_nmcpy(unsigned char *dst, char *src)
72 {
73        memcpy(dst, src, 8);
74 }
75 
76 static inline void low_nmcpy(unsigned char *dst, char *src)
77 {
78        memcpy(&dst[8], src, 8);
79 }
80 
81 /* Timers */
82 static void iucv_sock_timeout(unsigned long arg)
83 {
84 	struct sock *sk = (struct sock *)arg;
85 
86 	bh_lock_sock(sk);
87 	sk->sk_err = ETIMEDOUT;
88 	sk->sk_state_change(sk);
89 	bh_unlock_sock(sk);
90 
91 	iucv_sock_kill(sk);
92 	sock_put(sk);
93 }
94 
95 static void iucv_sock_clear_timer(struct sock *sk)
96 {
97 	sk_stop_timer(sk, &sk->sk_timer);
98 }
99 
100 static struct sock *__iucv_get_sock_by_name(char *nm)
101 {
102 	struct sock *sk;
103 	struct hlist_node *node;
104 
105 	sk_for_each(sk, node, &iucv_sk_list.head)
106 		if (!memcmp(&iucv_sk(sk)->src_name, nm, 8))
107 			return sk;
108 
109 	return NULL;
110 }
111 
112 static void iucv_sock_destruct(struct sock *sk)
113 {
114 	skb_queue_purge(&sk->sk_receive_queue);
115 	skb_queue_purge(&sk->sk_write_queue);
116 }
117 
118 /* Cleanup Listen */
119 static void iucv_sock_cleanup_listen(struct sock *parent)
120 {
121 	struct sock *sk;
122 
123 	/* Close non-accepted connections */
124 	while ((sk = iucv_accept_dequeue(parent, NULL))) {
125 		iucv_sock_close(sk);
126 		iucv_sock_kill(sk);
127 	}
128 
129 	parent->sk_state = IUCV_CLOSED;
130 	sock_set_flag(parent, SOCK_ZAPPED);
131 }
132 
133 /* Kill socket */
134 static void iucv_sock_kill(struct sock *sk)
135 {
136 	if (!sock_flag(sk, SOCK_ZAPPED) || sk->sk_socket)
137 		return;
138 
139 	iucv_sock_unlink(&iucv_sk_list, sk);
140 	sock_set_flag(sk, SOCK_DEAD);
141 	sock_put(sk);
142 }
143 
144 /* Close an IUCV socket */
145 static void iucv_sock_close(struct sock *sk)
146 {
147 	unsigned char user_data[16];
148 	struct iucv_sock *iucv = iucv_sk(sk);
149 	int err;
150 	unsigned long timeo;
151 
152 	iucv_sock_clear_timer(sk);
153 	lock_sock(sk);
154 
155 	switch (sk->sk_state) {
156 	case IUCV_LISTEN:
157 		iucv_sock_cleanup_listen(sk);
158 		break;
159 
160 	case IUCV_CONNECTED:
161 	case IUCV_DISCONN:
162 		err = 0;
163 
164 		sk->sk_state = IUCV_CLOSING;
165 		sk->sk_state_change(sk);
166 
167 		if (!skb_queue_empty(&iucv->send_skb_q)) {
168 			if (sock_flag(sk, SOCK_LINGER) && sk->sk_lingertime)
169 				timeo = sk->sk_lingertime;
170 			else
171 				timeo = IUCV_DISCONN_TIMEOUT;
172 			err = iucv_sock_wait_state(sk, IUCV_CLOSED, 0, timeo);
173 		}
174 
175 		sk->sk_state = IUCV_CLOSED;
176 		sk->sk_state_change(sk);
177 
178 		if (iucv->path) {
179 			low_nmcpy(user_data, iucv->src_name);
180 			high_nmcpy(user_data, iucv->dst_name);
181 			ASCEBC(user_data, sizeof(user_data));
182 			err = iucv_path_sever(iucv->path, user_data);
183 			iucv_path_free(iucv->path);
184 			iucv->path = NULL;
185 		}
186 
187 		sk->sk_err = ECONNRESET;
188 		sk->sk_state_change(sk);
189 
190 		skb_queue_purge(&iucv->send_skb_q);
191 		skb_queue_purge(&iucv->backlog_skb_q);
192 
193 		sock_set_flag(sk, SOCK_ZAPPED);
194 		break;
195 
196 	default:
197 		sock_set_flag(sk, SOCK_ZAPPED);
198 		break;
199 	}
200 
201 	release_sock(sk);
202 	iucv_sock_kill(sk);
203 }
204 
205 static void iucv_sock_init(struct sock *sk, struct sock *parent)
206 {
207 	if (parent)
208 		sk->sk_type = parent->sk_type;
209 }
210 
211 static struct sock *iucv_sock_alloc(struct socket *sock, int proto, gfp_t prio)
212 {
213 	struct sock *sk;
214 
215 	sk = sk_alloc(&init_net, PF_IUCV, prio, &iucv_proto);
216 	if (!sk)
217 		return NULL;
218 
219 	sock_init_data(sock, sk);
220 	INIT_LIST_HEAD(&iucv_sk(sk)->accept_q);
221 	spin_lock_init(&iucv_sk(sk)->accept_q_lock);
222 	skb_queue_head_init(&iucv_sk(sk)->send_skb_q);
223 	INIT_LIST_HEAD(&iucv_sk(sk)->message_q.list);
224 	spin_lock_init(&iucv_sk(sk)->message_q.lock);
225 	skb_queue_head_init(&iucv_sk(sk)->backlog_skb_q);
226 	iucv_sk(sk)->send_tag = 0;
227 
228 	sk->sk_destruct = iucv_sock_destruct;
229 	sk->sk_sndtimeo = IUCV_CONN_TIMEOUT;
230 	sk->sk_allocation = GFP_DMA;
231 
232 	sock_reset_flag(sk, SOCK_ZAPPED);
233 
234 	sk->sk_protocol = proto;
235 	sk->sk_state	= IUCV_OPEN;
236 
237 	setup_timer(&sk->sk_timer, iucv_sock_timeout, (unsigned long)sk);
238 
239 	iucv_sock_link(&iucv_sk_list, sk);
240 	return sk;
241 }
242 
243 /* Create an IUCV socket */
244 static int iucv_sock_create(struct net *net, struct socket *sock, int protocol)
245 {
246 	struct sock *sk;
247 
248 	if (sock->type != SOCK_STREAM)
249 		return -ESOCKTNOSUPPORT;
250 
251 	sock->state = SS_UNCONNECTED;
252 	sock->ops = &iucv_sock_ops;
253 
254 	sk = iucv_sock_alloc(sock, protocol, GFP_KERNEL);
255 	if (!sk)
256 		return -ENOMEM;
257 
258 	iucv_sock_init(sk, NULL);
259 
260 	return 0;
261 }
262 
263 void iucv_sock_link(struct iucv_sock_list *l, struct sock *sk)
264 {
265 	write_lock_bh(&l->lock);
266 	sk_add_node(sk, &l->head);
267 	write_unlock_bh(&l->lock);
268 }
269 
270 void iucv_sock_unlink(struct iucv_sock_list *l, struct sock *sk)
271 {
272 	write_lock_bh(&l->lock);
273 	sk_del_node_init(sk);
274 	write_unlock_bh(&l->lock);
275 }
276 
277 void iucv_accept_enqueue(struct sock *parent, struct sock *sk)
278 {
279 	unsigned long flags;
280 	struct iucv_sock *par = iucv_sk(parent);
281 
282 	sock_hold(sk);
283 	spin_lock_irqsave(&par->accept_q_lock, flags);
284 	list_add_tail(&iucv_sk(sk)->accept_q, &par->accept_q);
285 	spin_unlock_irqrestore(&par->accept_q_lock, flags);
286 	iucv_sk(sk)->parent = parent;
287 	parent->sk_ack_backlog++;
288 }
289 
290 void iucv_accept_unlink(struct sock *sk)
291 {
292 	unsigned long flags;
293 	struct iucv_sock *par = iucv_sk(iucv_sk(sk)->parent);
294 
295 	spin_lock_irqsave(&par->accept_q_lock, flags);
296 	list_del_init(&iucv_sk(sk)->accept_q);
297 	spin_unlock_irqrestore(&par->accept_q_lock, flags);
298 	iucv_sk(sk)->parent->sk_ack_backlog--;
299 	iucv_sk(sk)->parent = NULL;
300 	sock_put(sk);
301 }
302 
303 struct sock *iucv_accept_dequeue(struct sock *parent, struct socket *newsock)
304 {
305 	struct iucv_sock *isk, *n;
306 	struct sock *sk;
307 
308 	list_for_each_entry_safe(isk, n, &iucv_sk(parent)->accept_q, accept_q) {
309 		sk = (struct sock *) isk;
310 		lock_sock(sk);
311 
312 		if (sk->sk_state == IUCV_CLOSED) {
313 			iucv_accept_unlink(sk);
314 			release_sock(sk);
315 			continue;
316 		}
317 
318 		if (sk->sk_state == IUCV_CONNECTED ||
319 		    sk->sk_state == IUCV_SEVERED ||
320 		    !newsock) {
321 			iucv_accept_unlink(sk);
322 			if (newsock)
323 				sock_graft(sk, newsock);
324 
325 			if (sk->sk_state == IUCV_SEVERED)
326 				sk->sk_state = IUCV_DISCONN;
327 
328 			release_sock(sk);
329 			return sk;
330 		}
331 
332 		release_sock(sk);
333 	}
334 	return NULL;
335 }
336 
337 int iucv_sock_wait_state(struct sock *sk, int state, int state2,
338 			 unsigned long timeo)
339 {
340 	DECLARE_WAITQUEUE(wait, current);
341 	int err = 0;
342 
343 	add_wait_queue(sk->sk_sleep, &wait);
344 	while (sk->sk_state != state && sk->sk_state != state2) {
345 		set_current_state(TASK_INTERRUPTIBLE);
346 
347 		if (!timeo) {
348 			err = -EAGAIN;
349 			break;
350 		}
351 
352 		if (signal_pending(current)) {
353 			err = sock_intr_errno(timeo);
354 			break;
355 		}
356 
357 		release_sock(sk);
358 		timeo = schedule_timeout(timeo);
359 		lock_sock(sk);
360 
361 		err = sock_error(sk);
362 		if (err)
363 			break;
364 	}
365 	set_current_state(TASK_RUNNING);
366 	remove_wait_queue(sk->sk_sleep, &wait);
367 	return err;
368 }
369 
370 /* Bind an unbound socket */
371 static int iucv_sock_bind(struct socket *sock, struct sockaddr *addr,
372 			  int addr_len)
373 {
374 	struct sockaddr_iucv *sa = (struct sockaddr_iucv *) addr;
375 	struct sock *sk = sock->sk;
376 	struct iucv_sock *iucv;
377 	int err;
378 
379 	/* Verify the input sockaddr */
380 	if (!addr || addr->sa_family != AF_IUCV)
381 		return -EINVAL;
382 
383 	lock_sock(sk);
384 	if (sk->sk_state != IUCV_OPEN) {
385 		err = -EBADFD;
386 		goto done;
387 	}
388 
389 	write_lock_bh(&iucv_sk_list.lock);
390 
391 	iucv = iucv_sk(sk);
392 	if (__iucv_get_sock_by_name(sa->siucv_name)) {
393 		err = -EADDRINUSE;
394 		goto done_unlock;
395 	}
396 	if (iucv->path) {
397 		err = 0;
398 		goto done_unlock;
399 	}
400 
401 	/* Bind the socket */
402 	memcpy(iucv->src_name, sa->siucv_name, 8);
403 
404 	/* Copy the user id */
405 	memcpy(iucv->src_user_id, iucv_userid, 8);
406 	sk->sk_state = IUCV_BOUND;
407 	err = 0;
408 
409 done_unlock:
410 	/* Release the socket list lock */
411 	write_unlock_bh(&iucv_sk_list.lock);
412 done:
413 	release_sock(sk);
414 	return err;
415 }
416 
417 /* Automatically bind an unbound socket */
418 static int iucv_sock_autobind(struct sock *sk)
419 {
420 	struct iucv_sock *iucv = iucv_sk(sk);
421 	char query_buffer[80];
422 	char name[12];
423 	int err = 0;
424 
425 	/* Set the userid and name */
426 	cpcmd("QUERY USERID", query_buffer, sizeof(query_buffer), &err);
427 	if (unlikely(err))
428 		return -EPROTO;
429 
430 	memcpy(iucv->src_user_id, query_buffer, 8);
431 
432 	write_lock_bh(&iucv_sk_list.lock);
433 
434 	sprintf(name, "%08x", atomic_inc_return(&iucv_sk_list.autobind_name));
435 	while (__iucv_get_sock_by_name(name)) {
436 		sprintf(name, "%08x",
437 			atomic_inc_return(&iucv_sk_list.autobind_name));
438 	}
439 
440 	write_unlock_bh(&iucv_sk_list.lock);
441 
442 	memcpy(&iucv->src_name, name, 8);
443 
444 	return err;
445 }
446 
447 /* Connect an unconnected socket */
448 static int iucv_sock_connect(struct socket *sock, struct sockaddr *addr,
449 			     int alen, int flags)
450 {
451 	struct sockaddr_iucv *sa = (struct sockaddr_iucv *) addr;
452 	struct sock *sk = sock->sk;
453 	struct iucv_sock *iucv;
454 	unsigned char user_data[16];
455 	int err;
456 
457 	if (addr->sa_family != AF_IUCV || alen < sizeof(struct sockaddr_iucv))
458 		return -EINVAL;
459 
460 	if (sk->sk_state != IUCV_OPEN && sk->sk_state != IUCV_BOUND)
461 		return -EBADFD;
462 
463 	if (sk->sk_type != SOCK_STREAM)
464 		return -EINVAL;
465 
466 	iucv = iucv_sk(sk);
467 
468 	if (sk->sk_state == IUCV_OPEN) {
469 		err = iucv_sock_autobind(sk);
470 		if (unlikely(err))
471 			return err;
472 	}
473 
474 	lock_sock(sk);
475 
476 	/* Set the destination information */
477 	memcpy(iucv_sk(sk)->dst_user_id, sa->siucv_user_id, 8);
478 	memcpy(iucv_sk(sk)->dst_name, sa->siucv_name, 8);
479 
480 	high_nmcpy(user_data, sa->siucv_name);
481 	low_nmcpy(user_data, iucv_sk(sk)->src_name);
482 	ASCEBC(user_data, sizeof(user_data));
483 
484 	iucv = iucv_sk(sk);
485 	/* Create path. */
486 	iucv->path = iucv_path_alloc(IUCV_QUEUELEN_DEFAULT,
487 				     IPRMDATA, GFP_KERNEL);
488 	if (!iucv->path) {
489 		err = -ENOMEM;
490 		goto done;
491 	}
492 	err = iucv_path_connect(iucv->path, &af_iucv_handler,
493 				sa->siucv_user_id, NULL, user_data, sk);
494 	if (err) {
495 		iucv_path_free(iucv->path);
496 		iucv->path = NULL;
497 		switch (err) {
498 		case 0x0b:	/* Target communicator is not logged on */
499 			err = -ENETUNREACH;
500 			break;
501 		case 0x0d:	/* Max connections for this guest exceeded */
502 		case 0x0e:	/* Max connections for target guest exceeded */
503 			err = -EAGAIN;
504 			break;
505 		case 0x0f:	/* Missing IUCV authorization */
506 			err = -EACCES;
507 			break;
508 		default:
509 			err = -ECONNREFUSED;
510 			break;
511 		}
512 		goto done;
513 	}
514 
515 	if (sk->sk_state != IUCV_CONNECTED) {
516 		err = iucv_sock_wait_state(sk, IUCV_CONNECTED, IUCV_DISCONN,
517 				sock_sndtimeo(sk, flags & O_NONBLOCK));
518 	}
519 
520 	if (sk->sk_state == IUCV_DISCONN) {
521 		release_sock(sk);
522 		return -ECONNREFUSED;
523 	}
524 
525 	if (err) {
526 		iucv_path_sever(iucv->path, NULL);
527 		iucv_path_free(iucv->path);
528 		iucv->path = NULL;
529 	}
530 
531 done:
532 	release_sock(sk);
533 	return err;
534 }
535 
536 /* Move a socket into listening state. */
537 static int iucv_sock_listen(struct socket *sock, int backlog)
538 {
539 	struct sock *sk = sock->sk;
540 	int err;
541 
542 	lock_sock(sk);
543 
544 	err = -EINVAL;
545 	if (sk->sk_state != IUCV_BOUND || sock->type != SOCK_STREAM)
546 		goto done;
547 
548 	sk->sk_max_ack_backlog = backlog;
549 	sk->sk_ack_backlog = 0;
550 	sk->sk_state = IUCV_LISTEN;
551 	err = 0;
552 
553 done:
554 	release_sock(sk);
555 	return err;
556 }
557 
558 /* Accept a pending connection */
559 static int iucv_sock_accept(struct socket *sock, struct socket *newsock,
560 			    int flags)
561 {
562 	DECLARE_WAITQUEUE(wait, current);
563 	struct sock *sk = sock->sk, *nsk;
564 	long timeo;
565 	int err = 0;
566 
567 	lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
568 
569 	if (sk->sk_state != IUCV_LISTEN) {
570 		err = -EBADFD;
571 		goto done;
572 	}
573 
574 	timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
575 
576 	/* Wait for an incoming connection */
577 	add_wait_queue_exclusive(sk->sk_sleep, &wait);
578 	while (!(nsk = iucv_accept_dequeue(sk, newsock))) {
579 		set_current_state(TASK_INTERRUPTIBLE);
580 		if (!timeo) {
581 			err = -EAGAIN;
582 			break;
583 		}
584 
585 		release_sock(sk);
586 		timeo = schedule_timeout(timeo);
587 		lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
588 
589 		if (sk->sk_state != IUCV_LISTEN) {
590 			err = -EBADFD;
591 			break;
592 		}
593 
594 		if (signal_pending(current)) {
595 			err = sock_intr_errno(timeo);
596 			break;
597 		}
598 	}
599 
600 	set_current_state(TASK_RUNNING);
601 	remove_wait_queue(sk->sk_sleep, &wait);
602 
603 	if (err)
604 		goto done;
605 
606 	newsock->state = SS_CONNECTED;
607 
608 done:
609 	release_sock(sk);
610 	return err;
611 }
612 
613 static int iucv_sock_getname(struct socket *sock, struct sockaddr *addr,
614 			     int *len, int peer)
615 {
616 	struct sockaddr_iucv *siucv = (struct sockaddr_iucv *) addr;
617 	struct sock *sk = sock->sk;
618 
619 	addr->sa_family = AF_IUCV;
620 	*len = sizeof(struct sockaddr_iucv);
621 
622 	if (peer) {
623 		memcpy(siucv->siucv_user_id, iucv_sk(sk)->dst_user_id, 8);
624 		memcpy(siucv->siucv_name, &iucv_sk(sk)->dst_name, 8);
625 	} else {
626 		memcpy(siucv->siucv_user_id, iucv_sk(sk)->src_user_id, 8);
627 		memcpy(siucv->siucv_name, iucv_sk(sk)->src_name, 8);
628 	}
629 	memset(&siucv->siucv_port, 0, sizeof(siucv->siucv_port));
630 	memset(&siucv->siucv_addr, 0, sizeof(siucv->siucv_addr));
631 	memset(siucv->siucv_nodeid, 0, sizeof(siucv->siucv_nodeid));
632 
633 	return 0;
634 }
635 
636 static int iucv_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
637 			     struct msghdr *msg, size_t len)
638 {
639 	struct sock *sk = sock->sk;
640 	struct iucv_sock *iucv = iucv_sk(sk);
641 	struct sk_buff *skb;
642 	struct iucv_message txmsg;
643 	char user_id[9];
644 	char appl_id[9];
645 	int err;
646 
647 	err = sock_error(sk);
648 	if (err)
649 		return err;
650 
651 	if (msg->msg_flags & MSG_OOB)
652 		return -EOPNOTSUPP;
653 
654 	lock_sock(sk);
655 
656 	if (sk->sk_shutdown & SEND_SHUTDOWN) {
657 		err = -EPIPE;
658 		goto out;
659 	}
660 
661 	if (sk->sk_state == IUCV_CONNECTED) {
662 		if (!(skb = sock_alloc_send_skb(sk, len,
663 						msg->msg_flags & MSG_DONTWAIT,
664 						&err)))
665 			goto out;
666 
667 		if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
668 			err = -EFAULT;
669 			goto fail;
670 		}
671 
672 		txmsg.class = 0;
673 		memcpy(&txmsg.class, skb->data, skb->len >= 4 ? 4 : skb->len);
674 		txmsg.tag = iucv->send_tag++;
675 		memcpy(skb->cb, &txmsg.tag, 4);
676 		skb_queue_tail(&iucv->send_skb_q, skb);
677 		err = iucv_message_send(iucv->path, &txmsg, 0, 0,
678 					(void *) skb->data, skb->len);
679 		if (err) {
680 			if (err == 3) {
681 				user_id[8] = 0;
682 				memcpy(user_id, iucv->dst_user_id, 8);
683 				appl_id[8] = 0;
684 				memcpy(appl_id, iucv->dst_name, 8);
685 				pr_err("Application %s on z/VM guest %s"
686 				       " exceeds message limit\n",
687 				       user_id, appl_id);
688 			}
689 			skb_unlink(skb, &iucv->send_skb_q);
690 			err = -EPIPE;
691 			goto fail;
692 		}
693 
694 	} else {
695 		err = -ENOTCONN;
696 		goto out;
697 	}
698 
699 	release_sock(sk);
700 	return len;
701 
702 fail:
703 	kfree_skb(skb);
704 out:
705 	release_sock(sk);
706 	return err;
707 }
708 
709 static int iucv_fragment_skb(struct sock *sk, struct sk_buff *skb, int len)
710 {
711 	int dataleft, size, copied = 0;
712 	struct sk_buff *nskb;
713 
714 	dataleft = len;
715 	while (dataleft) {
716 		if (dataleft >= sk->sk_rcvbuf / 4)
717 			size = sk->sk_rcvbuf / 4;
718 		else
719 			size = dataleft;
720 
721 		nskb = alloc_skb(size, GFP_ATOMIC | GFP_DMA);
722 		if (!nskb)
723 			return -ENOMEM;
724 
725 		memcpy(nskb->data, skb->data + copied, size);
726 		copied += size;
727 		dataleft -= size;
728 
729 		skb_reset_transport_header(nskb);
730 		skb_reset_network_header(nskb);
731 		nskb->len = size;
732 
733 		skb_queue_tail(&iucv_sk(sk)->backlog_skb_q, nskb);
734 	}
735 
736 	return 0;
737 }
738 
739 static void iucv_process_message(struct sock *sk, struct sk_buff *skb,
740 				 struct iucv_path *path,
741 				 struct iucv_message *msg)
742 {
743 	int rc;
744 
745 	if (msg->flags & IPRMDATA) {
746 		skb->data = NULL;
747 		skb->len = 0;
748 	} else {
749 		rc = iucv_message_receive(path, msg, 0, skb->data,
750 					  msg->length, NULL);
751 		if (rc) {
752 			kfree_skb(skb);
753 			return;
754 		}
755 		if (skb->truesize >= sk->sk_rcvbuf / 4) {
756 			rc = iucv_fragment_skb(sk, skb, msg->length);
757 			kfree_skb(skb);
758 			skb = NULL;
759 			if (rc) {
760 				iucv_path_sever(path, NULL);
761 				return;
762 			}
763 			skb = skb_dequeue(&iucv_sk(sk)->backlog_skb_q);
764 		} else {
765 			skb_reset_transport_header(skb);
766 			skb_reset_network_header(skb);
767 			skb->len = msg->length;
768 		}
769 	}
770 
771 	if (sock_queue_rcv_skb(sk, skb))
772 		skb_queue_head(&iucv_sk(sk)->backlog_skb_q, skb);
773 }
774 
775 static void iucv_process_message_q(struct sock *sk)
776 {
777 	struct iucv_sock *iucv = iucv_sk(sk);
778 	struct sk_buff *skb;
779 	struct sock_msg_q *p, *n;
780 
781 	list_for_each_entry_safe(p, n, &iucv->message_q.list, list) {
782 		skb = alloc_skb(p->msg.length, GFP_ATOMIC | GFP_DMA);
783 		if (!skb)
784 			break;
785 		iucv_process_message(sk, skb, p->path, &p->msg);
786 		list_del(&p->list);
787 		kfree(p);
788 		if (!skb_queue_empty(&iucv->backlog_skb_q))
789 			break;
790 	}
791 }
792 
793 static int iucv_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
794 			     struct msghdr *msg, size_t len, int flags)
795 {
796 	int noblock = flags & MSG_DONTWAIT;
797 	struct sock *sk = sock->sk;
798 	struct iucv_sock *iucv = iucv_sk(sk);
799 	int target, copied = 0;
800 	struct sk_buff *skb, *rskb, *cskb;
801 	int err = 0;
802 
803 	if ((sk->sk_state == IUCV_DISCONN || sk->sk_state == IUCV_SEVERED) &&
804 	    skb_queue_empty(&iucv->backlog_skb_q) &&
805 	    skb_queue_empty(&sk->sk_receive_queue) &&
806 	    list_empty(&iucv->message_q.list))
807 		return 0;
808 
809 	if (flags & (MSG_OOB))
810 		return -EOPNOTSUPP;
811 
812 	target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
813 
814 	skb = skb_recv_datagram(sk, flags, noblock, &err);
815 	if (!skb) {
816 		if (sk->sk_shutdown & RCV_SHUTDOWN)
817 			return 0;
818 		return err;
819 	}
820 
821 	copied = min_t(unsigned int, skb->len, len);
822 
823 	cskb = skb;
824 	if (memcpy_toiovec(msg->msg_iov, cskb->data, copied)) {
825 		skb_queue_head(&sk->sk_receive_queue, skb);
826 		if (copied == 0)
827 			return -EFAULT;
828 		goto done;
829 	}
830 
831 	len -= copied;
832 
833 	/* Mark read part of skb as used */
834 	if (!(flags & MSG_PEEK)) {
835 		skb_pull(skb, copied);
836 
837 		if (skb->len) {
838 			skb_queue_head(&sk->sk_receive_queue, skb);
839 			goto done;
840 		}
841 
842 		kfree_skb(skb);
843 
844 		/* Queue backlog skbs */
845 		rskb = skb_dequeue(&iucv->backlog_skb_q);
846 		while (rskb) {
847 			if (sock_queue_rcv_skb(sk, rskb)) {
848 				skb_queue_head(&iucv->backlog_skb_q,
849 						rskb);
850 				break;
851 			} else {
852 				rskb = skb_dequeue(&iucv->backlog_skb_q);
853 			}
854 		}
855 		if (skb_queue_empty(&iucv->backlog_skb_q)) {
856 			spin_lock_bh(&iucv->message_q.lock);
857 			if (!list_empty(&iucv->message_q.list))
858 				iucv_process_message_q(sk);
859 			spin_unlock_bh(&iucv->message_q.lock);
860 		}
861 
862 	} else
863 		skb_queue_head(&sk->sk_receive_queue, skb);
864 
865 done:
866 	return err ? : copied;
867 }
868 
869 static inline unsigned int iucv_accept_poll(struct sock *parent)
870 {
871 	struct iucv_sock *isk, *n;
872 	struct sock *sk;
873 
874 	list_for_each_entry_safe(isk, n, &iucv_sk(parent)->accept_q, accept_q) {
875 		sk = (struct sock *) isk;
876 
877 		if (sk->sk_state == IUCV_CONNECTED)
878 			return POLLIN | POLLRDNORM;
879 	}
880 
881 	return 0;
882 }
883 
884 unsigned int iucv_sock_poll(struct file *file, struct socket *sock,
885 			    poll_table *wait)
886 {
887 	struct sock *sk = sock->sk;
888 	unsigned int mask = 0;
889 
890 	poll_wait(file, sk->sk_sleep, wait);
891 
892 	if (sk->sk_state == IUCV_LISTEN)
893 		return iucv_accept_poll(sk);
894 
895 	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
896 		mask |= POLLERR;
897 
898 	if (sk->sk_shutdown & RCV_SHUTDOWN)
899 		mask |= POLLRDHUP;
900 
901 	if (sk->sk_shutdown == SHUTDOWN_MASK)
902 		mask |= POLLHUP;
903 
904 	if (!skb_queue_empty(&sk->sk_receive_queue) ||
905 	    (sk->sk_shutdown & RCV_SHUTDOWN))
906 		mask |= POLLIN | POLLRDNORM;
907 
908 	if (sk->sk_state == IUCV_CLOSED)
909 		mask |= POLLHUP;
910 
911 	if (sk->sk_state == IUCV_DISCONN || sk->sk_state == IUCV_SEVERED)
912 		mask |= POLLIN;
913 
914 	if (sock_writeable(sk))
915 		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
916 	else
917 		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
918 
919 	return mask;
920 }
921 
922 static int iucv_sock_shutdown(struct socket *sock, int how)
923 {
924 	struct sock *sk = sock->sk;
925 	struct iucv_sock *iucv = iucv_sk(sk);
926 	struct iucv_message txmsg;
927 	int err = 0;
928 	u8 prmmsg[8] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01};
929 
930 	how++;
931 
932 	if ((how & ~SHUTDOWN_MASK) || !how)
933 		return -EINVAL;
934 
935 	lock_sock(sk);
936 	switch (sk->sk_state) {
937 	case IUCV_CLOSED:
938 		err = -ENOTCONN;
939 		goto fail;
940 
941 	default:
942 		sk->sk_shutdown |= how;
943 		break;
944 	}
945 
946 	if (how == SEND_SHUTDOWN || how == SHUTDOWN_MASK) {
947 		txmsg.class = 0;
948 		txmsg.tag = 0;
949 		err = iucv_message_send(iucv->path, &txmsg, IUCV_IPRMDATA, 0,
950 					(void *) prmmsg, 8);
951 		if (err) {
952 			switch (err) {
953 			case 1:
954 				err = -ENOTCONN;
955 				break;
956 			case 2:
957 				err = -ECONNRESET;
958 				break;
959 			default:
960 				err = -ENOTCONN;
961 				break;
962 			}
963 		}
964 	}
965 
966 	if (how == RCV_SHUTDOWN || how == SHUTDOWN_MASK) {
967 		err = iucv_path_quiesce(iucv_sk(sk)->path, NULL);
968 		if (err)
969 			err = -ENOTCONN;
970 
971 		skb_queue_purge(&sk->sk_receive_queue);
972 	}
973 
974 	/* Wake up anyone sleeping in poll */
975 	sk->sk_state_change(sk);
976 
977 fail:
978 	release_sock(sk);
979 	return err;
980 }
981 
982 static int iucv_sock_release(struct socket *sock)
983 {
984 	struct sock *sk = sock->sk;
985 	int err = 0;
986 
987 	if (!sk)
988 		return 0;
989 
990 	iucv_sock_close(sk);
991 
992 	/* Unregister with IUCV base support */
993 	if (iucv_sk(sk)->path) {
994 		iucv_path_sever(iucv_sk(sk)->path, NULL);
995 		iucv_path_free(iucv_sk(sk)->path);
996 		iucv_sk(sk)->path = NULL;
997 	}
998 
999 	sock_orphan(sk);
1000 	iucv_sock_kill(sk);
1001 	return err;
1002 }
1003 
1004 /* Callback wrappers - called from iucv base support */
1005 static int iucv_callback_connreq(struct iucv_path *path,
1006 				 u8 ipvmid[8], u8 ipuser[16])
1007 {
1008 	unsigned char user_data[16];
1009 	unsigned char nuser_data[16];
1010 	unsigned char src_name[8];
1011 	struct hlist_node *node;
1012 	struct sock *sk, *nsk;
1013 	struct iucv_sock *iucv, *niucv;
1014 	int err;
1015 
1016 	memcpy(src_name, ipuser, 8);
1017 	EBCASC(src_name, 8);
1018 	/* Find out if this path belongs to af_iucv. */
1019 	read_lock(&iucv_sk_list.lock);
1020 	iucv = NULL;
1021 	sk = NULL;
1022 	sk_for_each(sk, node, &iucv_sk_list.head)
1023 		if (sk->sk_state == IUCV_LISTEN &&
1024 		    !memcmp(&iucv_sk(sk)->src_name, src_name, 8)) {
1025 			/*
1026 			 * Found a listening socket with
1027 			 * src_name == ipuser[0-7].
1028 			 */
1029 			iucv = iucv_sk(sk);
1030 			break;
1031 		}
1032 	read_unlock(&iucv_sk_list.lock);
1033 	if (!iucv)
1034 		/* No socket found, not one of our paths. */
1035 		return -EINVAL;
1036 
1037 	bh_lock_sock(sk);
1038 
1039 	/* Check if parent socket is listening */
1040 	low_nmcpy(user_data, iucv->src_name);
1041 	high_nmcpy(user_data, iucv->dst_name);
1042 	ASCEBC(user_data, sizeof(user_data));
1043 	if (sk->sk_state != IUCV_LISTEN) {
1044 		err = iucv_path_sever(path, user_data);
1045 		iucv_path_free(path);
1046 		goto fail;
1047 	}
1048 
1049 	/* Check for backlog size */
1050 	if (sk_acceptq_is_full(sk)) {
1051 		err = iucv_path_sever(path, user_data);
1052 		iucv_path_free(path);
1053 		goto fail;
1054 	}
1055 
1056 	/* Create the new socket */
1057 	nsk = iucv_sock_alloc(NULL, SOCK_STREAM, GFP_ATOMIC);
1058 	if (!nsk) {
1059 		err = iucv_path_sever(path, user_data);
1060 		iucv_path_free(path);
1061 		goto fail;
1062 	}
1063 
1064 	niucv = iucv_sk(nsk);
1065 	iucv_sock_init(nsk, sk);
1066 
1067 	/* Set the new iucv_sock */
1068 	memcpy(niucv->dst_name, ipuser + 8, 8);
1069 	EBCASC(niucv->dst_name, 8);
1070 	memcpy(niucv->dst_user_id, ipvmid, 8);
1071 	memcpy(niucv->src_name, iucv->src_name, 8);
1072 	memcpy(niucv->src_user_id, iucv->src_user_id, 8);
1073 	niucv->path = path;
1074 
1075 	/* Call iucv_accept */
1076 	high_nmcpy(nuser_data, ipuser + 8);
1077 	memcpy(nuser_data + 8, niucv->src_name, 8);
1078 	ASCEBC(nuser_data + 8, 8);
1079 
1080 	path->msglim = IUCV_QUEUELEN_DEFAULT;
1081 	err = iucv_path_accept(path, &af_iucv_handler, nuser_data, nsk);
1082 	if (err) {
1083 		err = iucv_path_sever(path, user_data);
1084 		iucv_path_free(path);
1085 		iucv_sock_kill(nsk);
1086 		goto fail;
1087 	}
1088 
1089 	iucv_accept_enqueue(sk, nsk);
1090 
1091 	/* Wake up accept */
1092 	nsk->sk_state = IUCV_CONNECTED;
1093 	sk->sk_data_ready(sk, 1);
1094 	err = 0;
1095 fail:
1096 	bh_unlock_sock(sk);
1097 	return 0;
1098 }
1099 
1100 static void iucv_callback_connack(struct iucv_path *path, u8 ipuser[16])
1101 {
1102 	struct sock *sk = path->private;
1103 
1104 	sk->sk_state = IUCV_CONNECTED;
1105 	sk->sk_state_change(sk);
1106 }
1107 
1108 static void iucv_callback_rx(struct iucv_path *path, struct iucv_message *msg)
1109 {
1110 	struct sock *sk = path->private;
1111 	struct iucv_sock *iucv = iucv_sk(sk);
1112 	struct sk_buff *skb;
1113 	struct sock_msg_q *save_msg;
1114 	int len;
1115 
1116 	if (sk->sk_shutdown & RCV_SHUTDOWN)
1117 		return;
1118 
1119 	if (!list_empty(&iucv->message_q.list) ||
1120 	    !skb_queue_empty(&iucv->backlog_skb_q))
1121 		goto save_message;
1122 
1123 	len = atomic_read(&sk->sk_rmem_alloc);
1124 	len += msg->length + sizeof(struct sk_buff);
1125 	if (len > sk->sk_rcvbuf)
1126 		goto save_message;
1127 
1128 	skb = alloc_skb(msg->length, GFP_ATOMIC | GFP_DMA);
1129 	if (!skb)
1130 		goto save_message;
1131 
1132 	spin_lock(&iucv->message_q.lock);
1133 	iucv_process_message(sk, skb, path, msg);
1134 	spin_unlock(&iucv->message_q.lock);
1135 
1136 	return;
1137 
1138 save_message:
1139 	save_msg = kzalloc(sizeof(struct sock_msg_q), GFP_ATOMIC | GFP_DMA);
1140 	if (!save_msg)
1141 		return;
1142 	save_msg->path = path;
1143 	save_msg->msg = *msg;
1144 
1145 	spin_lock(&iucv->message_q.lock);
1146 	list_add_tail(&save_msg->list, &iucv->message_q.list);
1147 	spin_unlock(&iucv->message_q.lock);
1148 }
1149 
1150 static void iucv_callback_txdone(struct iucv_path *path,
1151 				 struct iucv_message *msg)
1152 {
1153 	struct sock *sk = path->private;
1154 	struct sk_buff *this = NULL;
1155 	struct sk_buff_head *list = &iucv_sk(sk)->send_skb_q;
1156 	struct sk_buff *list_skb = list->next;
1157 	unsigned long flags;
1158 
1159 	if (!skb_queue_empty(list)) {
1160 		spin_lock_irqsave(&list->lock, flags);
1161 
1162 		while (list_skb != (struct sk_buff *)list) {
1163 			if (!memcmp(&msg->tag, list_skb->cb, 4)) {
1164 				this = list_skb;
1165 				break;
1166 			}
1167 			list_skb = list_skb->next;
1168 		}
1169 		if (this)
1170 			__skb_unlink(this, list);
1171 
1172 		spin_unlock_irqrestore(&list->lock, flags);
1173 
1174 		kfree_skb(this);
1175 	}
1176 	BUG_ON(!this);
1177 
1178 	if (sk->sk_state == IUCV_CLOSING) {
1179 		if (skb_queue_empty(&iucv_sk(sk)->send_skb_q)) {
1180 			sk->sk_state = IUCV_CLOSED;
1181 			sk->sk_state_change(sk);
1182 		}
1183 	}
1184 
1185 }
1186 
1187 static void iucv_callback_connrej(struct iucv_path *path, u8 ipuser[16])
1188 {
1189 	struct sock *sk = path->private;
1190 
1191 	if (!list_empty(&iucv_sk(sk)->accept_q))
1192 		sk->sk_state = IUCV_SEVERED;
1193 	else
1194 		sk->sk_state = IUCV_DISCONN;
1195 
1196 	sk->sk_state_change(sk);
1197 }
1198 
1199 static struct proto_ops iucv_sock_ops = {
1200 	.family		= PF_IUCV,
1201 	.owner		= THIS_MODULE,
1202 	.release	= iucv_sock_release,
1203 	.bind		= iucv_sock_bind,
1204 	.connect	= iucv_sock_connect,
1205 	.listen		= iucv_sock_listen,
1206 	.accept		= iucv_sock_accept,
1207 	.getname	= iucv_sock_getname,
1208 	.sendmsg	= iucv_sock_sendmsg,
1209 	.recvmsg	= iucv_sock_recvmsg,
1210 	.poll		= iucv_sock_poll,
1211 	.ioctl		= sock_no_ioctl,
1212 	.mmap		= sock_no_mmap,
1213 	.socketpair	= sock_no_socketpair,
1214 	.shutdown	= iucv_sock_shutdown,
1215 	.setsockopt	= sock_no_setsockopt,
1216 	.getsockopt	= sock_no_getsockopt
1217 };
1218 
1219 static struct net_proto_family iucv_sock_family_ops = {
1220 	.family	= AF_IUCV,
1221 	.owner	= THIS_MODULE,
1222 	.create	= iucv_sock_create,
1223 };
1224 
1225 static int __init afiucv_init(void)
1226 {
1227 	int err;
1228 
1229 	if (!MACHINE_IS_VM) {
1230 		pr_err("The af_iucv module cannot be loaded"
1231 		       " without z/VM\n");
1232 		err = -EPROTONOSUPPORT;
1233 		goto out;
1234 	}
1235 	cpcmd("QUERY USERID", iucv_userid, sizeof(iucv_userid), &err);
1236 	if (unlikely(err)) {
1237 		WARN_ON(err);
1238 		err = -EPROTONOSUPPORT;
1239 		goto out;
1240 	}
1241 
1242 	err = iucv_register(&af_iucv_handler, 0);
1243 	if (err)
1244 		goto out;
1245 	err = proto_register(&iucv_proto, 0);
1246 	if (err)
1247 		goto out_iucv;
1248 	err = sock_register(&iucv_sock_family_ops);
1249 	if (err)
1250 		goto out_proto;
1251 	return 0;
1252 
1253 out_proto:
1254 	proto_unregister(&iucv_proto);
1255 out_iucv:
1256 	iucv_unregister(&af_iucv_handler, 0);
1257 out:
1258 	return err;
1259 }
1260 
1261 static void __exit afiucv_exit(void)
1262 {
1263 	sock_unregister(PF_IUCV);
1264 	proto_unregister(&iucv_proto);
1265 	iucv_unregister(&af_iucv_handler, 0);
1266 }
1267 
1268 module_init(afiucv_init);
1269 module_exit(afiucv_exit);
1270 
1271 MODULE_AUTHOR("Jennifer Hunt <jenhunt@us.ibm.com>");
1272 MODULE_DESCRIPTION("IUCV Sockets ver " VERSION);
1273 MODULE_VERSION(VERSION);
1274 MODULE_LICENSE("GPL");
1275 MODULE_ALIAS_NETPROTO(PF_IUCV);
1276