xref: /linux/net/iucv/af_iucv.c (revision 21ef2d065ad3f0cfbf2ae51260bf962a9fa2c643)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  IUCV protocol stack for Linux on zSeries
4  *
5  *  Copyright IBM Corp. 2006, 2009
6  *
7  *  Author(s):	Jennifer Hunt <jenhunt@us.ibm.com>
8  *		Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
9  *  PM functions:
10  *		Ursula Braun <ursula.braun@de.ibm.com>
11  */
12 
13 #define pr_fmt(fmt) "af_iucv: " fmt
14 
15 #include <linux/filter.h>
16 #include <linux/module.h>
17 #include <linux/netdevice.h>
18 #include <linux/types.h>
19 #include <linux/limits.h>
20 #include <linux/list.h>
21 #include <linux/errno.h>
22 #include <linux/kernel.h>
23 #include <linux/sched/signal.h>
24 #include <linux/slab.h>
25 #include <linux/skbuff.h>
26 #include <linux/init.h>
27 #include <linux/poll.h>
28 #include <linux/security.h>
29 #include <linux/uio.h>
30 #include <net/sock.h>
31 #include <asm/machine.h>
32 #include <asm/ebcdic.h>
33 #include <asm/cpcmd.h>
34 #include <linux/kmod.h>
35 
36 #include <net/iucv/af_iucv.h>
37 
38 #define VERSION "1.2"
39 
40 static char iucv_userid[80];
41 
42 static struct proto iucv_proto = {
43 	.name		= "AF_IUCV",
44 	.owner		= THIS_MODULE,
45 	.obj_size	= sizeof(struct iucv_sock),
46 };
47 
48 static struct iucv_interface *pr_iucv;
49 static struct iucv_handler af_iucv_handler;
50 
51 /* special AF_IUCV IPRM messages */
52 static const u8 iprm_shutdown[8] =
53 	{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01};
54 
55 #define TRGCLS_SIZE	sizeof_field(struct iucv_message, class)
56 
57 #define __iucv_sock_wait(sk, condition, timeo, ret)			\
58 do {									\
59 	DEFINE_WAIT(__wait);						\
60 	long __timeo = timeo;						\
61 	ret = 0;							\
62 	prepare_to_wait(sk_sleep(sk), &__wait, TASK_INTERRUPTIBLE);	\
63 	while (!(condition)) {						\
64 		if (!__timeo) {						\
65 			ret = -EAGAIN;					\
66 			break;						\
67 		}							\
68 		if (signal_pending(current)) {				\
69 			ret = sock_intr_errno(__timeo);			\
70 			break;						\
71 		}							\
72 		release_sock(sk);					\
73 		__timeo = schedule_timeout(__timeo);			\
74 		lock_sock(sk);						\
75 		ret = sock_error(sk);					\
76 		if (ret)						\
77 			break;						\
78 	}								\
79 	finish_wait(sk_sleep(sk), &__wait);				\
80 } while (0)
81 
82 #define iucv_sock_wait(sk, condition, timeo)				\
83 ({									\
84 	int __ret = 0;							\
85 	if (!(condition))						\
86 		__iucv_sock_wait(sk, condition, timeo, __ret);		\
87 	__ret;								\
88 })
89 
90 static struct sock *iucv_accept_dequeue(struct sock *parent,
91 					struct socket *newsock);
92 static void iucv_sock_kill(struct sock *sk);
93 static void iucv_sock_close(struct sock *sk);
94 
95 static void afiucv_hs_callback_txnotify(struct sock *sk, enum iucv_tx_notify);
96 
97 static struct iucv_sock_list iucv_sk_list = {
98 	.lock = __RW_LOCK_UNLOCKED(iucv_sk_list.lock),
99 	.autobind_name = ATOMIC_INIT(0)
100 };
101 
102 static inline void high_nmcpy(unsigned char *dst, char *src)
103 {
104        memcpy(dst, src, 8);
105 }
106 
107 static inline void low_nmcpy(unsigned char *dst, char *src)
108 {
109        memcpy(&dst[8], src, 8);
110 }
111 
112 /**
113  * iucv_msg_length() - Returns the length of an iucv message.
114  * @msg:	Pointer to struct iucv_message, MUST NOT be NULL
115  *
116  * The function returns the length of the specified iucv message @msg of data
117  * stored in a buffer and of data stored in the parameter list (PRMDATA).
118  *
119  * For IUCV_IPRMDATA, AF_IUCV uses the following convention to transport socket
120  * data:
121  *	PRMDATA[0..6]	socket data (max 7 bytes);
122  *	PRMDATA[7]	socket data length value (len is 0xff - PRMDATA[7])
123  *
124  * The socket data length is computed by subtracting the socket data length
125  * value from 0xFF.
126  * If the socket data len is greater 7, then PRMDATA can be used for special
127  * notifications (see iucv_sock_shutdown); and further,
128  * if the socket data len is > 7, the function returns 8.
129  *
130  * Use this function to allocate socket buffers to store iucv message data.
131  *
132  * Returns: Length of the IUCV message.
133  */
134 static inline size_t iucv_msg_length(struct iucv_message *msg)
135 {
136 	size_t datalen;
137 
138 	if (msg->flags & IUCV_IPRMDATA) {
139 		datalen = 0xff - msg->rmmsg[7];
140 		return (datalen < 8) ? datalen : 8;
141 	}
142 	return msg->length;
143 }
144 
145 /**
146  * iucv_sock_in_state() - check for specific states
147  * @sk:		sock structure
148  * @state:	first iucv sk state
149  * @state2:	second iucv sk state
150  *
151  * Returns: true if the socket is either in the first or second state.
152  */
153 static int iucv_sock_in_state(struct sock *sk, int state, int state2)
154 {
155 	return (sk->sk_state == state || sk->sk_state == state2);
156 }
157 
158 /**
159  * iucv_below_msglim() - function to check if messages can be sent
160  * @sk:		sock structure
161  *
162  * Returns: true, if either the socket is not connected (no iucv path for
163  * checking the message limit) or if the send queue length is lower
164  * than the message limit.
165  */
166 static inline int iucv_below_msglim(struct sock *sk)
167 {
168 	struct iucv_sock *iucv = iucv_sk(sk);
169 
170 	if (sk->sk_state != IUCV_CONNECTED)
171 		return 1;
172 	if (iucv->transport == AF_IUCV_TRANS_IUCV)
173 		return (atomic_read(&iucv->skbs_in_xmit) < iucv->path->msglim);
174 	else
175 		return ((atomic_read(&iucv->msg_sent) < iucv->msglimit_peer) &&
176 			(atomic_read(&iucv->pendings) <= 0));
177 }
178 
179 /*
180  * iucv_sock_wake_msglim() - Wake up thread waiting on msg limit
181  */
182 static void iucv_sock_wake_msglim(struct sock *sk)
183 {
184 	struct socket_wq *wq;
185 
186 	rcu_read_lock();
187 	wq = rcu_dereference(sk->sk_wq);
188 	if (skwq_has_sleeper(wq))
189 		wake_up_interruptible_all(&wq->wait);
190 	sk_wake_async_rcu(sk, SOCK_WAKE_SPACE, POLL_OUT);
191 	rcu_read_unlock();
192 }
193 
194 /*
195  * afiucv_hs_send() - send a message through HiperSockets transport
196  */
197 static int afiucv_hs_send(struct iucv_message *imsg, struct sock *sock,
198 		   struct sk_buff *skb, u8 flags)
199 {
200 	struct iucv_sock *iucv = iucv_sk(sock);
201 	struct af_iucv_trans_hdr *phs_hdr;
202 	int err, confirm_recv = 0;
203 
204 	phs_hdr = skb_push(skb, sizeof(*phs_hdr));
205 	memset(phs_hdr, 0, sizeof(*phs_hdr));
206 	skb_reset_network_header(skb);
207 
208 	phs_hdr->magic = ETH_P_AF_IUCV;
209 	phs_hdr->version = 1;
210 	phs_hdr->flags = flags;
211 	if (flags == AF_IUCV_FLAG_SYN)
212 		phs_hdr->window = iucv->msglimit;
213 	else if ((flags == AF_IUCV_FLAG_WIN) || !flags) {
214 		confirm_recv = atomic_read(&iucv->msg_recv);
215 		phs_hdr->window = confirm_recv;
216 		if (confirm_recv)
217 			phs_hdr->flags = phs_hdr->flags | AF_IUCV_FLAG_WIN;
218 	}
219 	memcpy(phs_hdr->destUserID, iucv->dst_user_id, 8);
220 	memcpy(phs_hdr->destAppName, iucv->dst_name, 8);
221 	memcpy(phs_hdr->srcUserID, iucv->src_user_id, 8);
222 	memcpy(phs_hdr->srcAppName, iucv->src_name, 8);
223 	ASCEBC(phs_hdr->destUserID, sizeof(phs_hdr->destUserID));
224 	ASCEBC(phs_hdr->destAppName, sizeof(phs_hdr->destAppName));
225 	ASCEBC(phs_hdr->srcUserID, sizeof(phs_hdr->srcUserID));
226 	ASCEBC(phs_hdr->srcAppName, sizeof(phs_hdr->srcAppName));
227 	if (imsg)
228 		memcpy(&phs_hdr->iucv_hdr, imsg, sizeof(struct iucv_message));
229 
230 	skb->dev = iucv->hs_dev;
231 	if (!skb->dev) {
232 		err = -ENODEV;
233 		goto err_free;
234 	}
235 
236 	dev_hard_header(skb, skb->dev, ETH_P_AF_IUCV, NULL, NULL, skb->len);
237 
238 	if (!(skb->dev->flags & IFF_UP) || !netif_carrier_ok(skb->dev)) {
239 		err = -ENETDOWN;
240 		goto err_free;
241 	}
242 	if (skb->len > skb->dev->mtu) {
243 		if (sock->sk_type == SOCK_SEQPACKET) {
244 			err = -EMSGSIZE;
245 			goto err_free;
246 		}
247 		err = pskb_trim(skb, skb->dev->mtu);
248 		if (err)
249 			goto err_free;
250 	}
251 	skb->protocol = cpu_to_be16(ETH_P_AF_IUCV);
252 
253 	atomic_inc(&iucv->skbs_in_xmit);
254 	err = dev_queue_xmit(skb);
255 	if (net_xmit_eval(err)) {
256 		atomic_dec(&iucv->skbs_in_xmit);
257 	} else {
258 		atomic_sub(confirm_recv, &iucv->msg_recv);
259 		WARN_ON(atomic_read(&iucv->msg_recv) < 0);
260 	}
261 	return net_xmit_eval(err);
262 
263 err_free:
264 	kfree_skb(skb);
265 	return err;
266 }
267 
268 static struct sock *__iucv_get_sock_by_name(char *nm)
269 {
270 	struct sock *sk;
271 
272 	sk_for_each(sk, &iucv_sk_list.head)
273 		if (!memcmp(&iucv_sk(sk)->src_name, nm, 8))
274 			return sk;
275 
276 	return NULL;
277 }
278 
279 static void iucv_sock_destruct(struct sock *sk)
280 {
281 	skb_queue_purge(&sk->sk_receive_queue);
282 	skb_queue_purge(&sk->sk_error_queue);
283 
284 	if (!sock_flag(sk, SOCK_DEAD)) {
285 		pr_err("Attempt to release alive iucv socket %p\n", sk);
286 		return;
287 	}
288 
289 	WARN_ON(atomic_read(&sk->sk_rmem_alloc));
290 	WARN_ON(refcount_read(&sk->sk_wmem_alloc));
291 	WARN_ON(sk->sk_wmem_queued);
292 	WARN_ON(sk->sk_forward_alloc);
293 }
294 
295 /* Cleanup Listen */
296 static void iucv_sock_cleanup_listen(struct sock *parent)
297 {
298 	struct sock *sk;
299 
300 	/* Close non-accepted connections */
301 	while ((sk = iucv_accept_dequeue(parent, NULL))) {
302 		iucv_sock_close(sk);
303 		iucv_sock_kill(sk);
304 	}
305 
306 	parent->sk_state = IUCV_CLOSED;
307 }
308 
309 static void iucv_sock_link(struct iucv_sock_list *l, struct sock *sk)
310 {
311 	write_lock_bh(&l->lock);
312 	sk_add_node(sk, &l->head);
313 	write_unlock_bh(&l->lock);
314 }
315 
316 static void iucv_sock_unlink(struct iucv_sock_list *l, struct sock *sk)
317 {
318 	write_lock_bh(&l->lock);
319 	sk_del_node_init(sk);
320 	write_unlock_bh(&l->lock);
321 }
322 
323 /* Kill socket (only if zapped and orphaned) */
324 static void iucv_sock_kill(struct sock *sk)
325 {
326 	if (!sock_flag(sk, SOCK_ZAPPED) || sk->sk_socket)
327 		return;
328 
329 	iucv_sock_unlink(&iucv_sk_list, sk);
330 	sock_set_flag(sk, SOCK_DEAD);
331 	sock_put(sk);
332 }
333 
334 /* Terminate an IUCV path */
335 static void iucv_sever_path(struct sock *sk, int with_user_data)
336 {
337 	unsigned char user_data[16];
338 	struct iucv_sock *iucv = iucv_sk(sk);
339 	struct iucv_path *path = iucv->path;
340 	struct sock_msg_q *p, *n;
341 
342 	/* Whoever resets the path pointer, must sever and free it. */
343 	if (xchg(&iucv->path, NULL)) {
344 		if (with_user_data) {
345 			low_nmcpy(user_data, iucv->src_name);
346 			high_nmcpy(user_data, iucv->dst_name);
347 			ASCEBC(user_data, sizeof(user_data));
348 			pr_iucv->path_sever(path, user_data);
349 		} else
350 			pr_iucv->path_sever(path, NULL);
351 		iucv_path_free(path);
352 
353 		/*
354 		 * Message notifications queued on message_q still reference
355 		 * the now freed path; drop them, otherwise a later recvmsg()
356 		 * would pass the freed iucv_path to message_receive() via
357 		 * iucv_process_message_q().
358 		 */
359 		spin_lock_bh(&iucv->message_q.lock);
360 		list_for_each_entry_safe(p, n, &iucv->message_q.list, list) {
361 			list_del(&p->list);
362 			kfree(p);
363 		}
364 		spin_unlock_bh(&iucv->message_q.lock);
365 	}
366 }
367 
368 /* Send controlling flags through an IUCV socket for HIPER transport */
369 static int iucv_send_ctrl(struct sock *sk, u8 flags)
370 {
371 	struct iucv_sock *iucv = iucv_sk(sk);
372 	int err = 0;
373 	int blen;
374 	struct sk_buff *skb;
375 	u8 shutdown = 0;
376 
377 	blen = sizeof(struct af_iucv_trans_hdr) +
378 	       LL_RESERVED_SPACE(iucv->hs_dev);
379 	if (sk->sk_shutdown & SEND_SHUTDOWN) {
380 		/* controlling flags should be sent anyway */
381 		shutdown = sk->sk_shutdown;
382 		sk->sk_shutdown &= RCV_SHUTDOWN;
383 	}
384 	skb = sock_alloc_send_skb(sk, blen, 1, &err);
385 	if (skb) {
386 		skb_reserve(skb, blen);
387 		err = afiucv_hs_send(NULL, sk, skb, flags);
388 	}
389 	if (shutdown)
390 		sk->sk_shutdown = shutdown;
391 	return err;
392 }
393 
394 /* Close an IUCV socket */
395 static void iucv_sock_close(struct sock *sk)
396 {
397 	struct iucv_sock *iucv = iucv_sk(sk);
398 	unsigned long timeo;
399 	int err = 0;
400 
401 	lock_sock(sk);
402 
403 	switch (sk->sk_state) {
404 	case IUCV_LISTEN:
405 		iucv_sock_cleanup_listen(sk);
406 		break;
407 
408 	case IUCV_CONNECTED:
409 		if (iucv->transport == AF_IUCV_TRANS_HIPER) {
410 			err = iucv_send_ctrl(sk, AF_IUCV_FLAG_FIN);
411 			sk->sk_state = IUCV_DISCONN;
412 			sk->sk_state_change(sk);
413 		}
414 		fallthrough;
415 
416 	case IUCV_DISCONN:
417 		sk->sk_state = IUCV_CLOSING;
418 		sk->sk_state_change(sk);
419 
420 		if (!err && atomic_read(&iucv->skbs_in_xmit) > 0) {
421 			if (sock_flag(sk, SOCK_LINGER) && sk->sk_lingertime)
422 				timeo = sk->sk_lingertime;
423 			else
424 				timeo = IUCV_DISCONN_TIMEOUT;
425 			iucv_sock_wait(sk,
426 					iucv_sock_in_state(sk, IUCV_CLOSED, 0),
427 					timeo);
428 		}
429 		fallthrough;
430 
431 	case IUCV_CLOSING:
432 		sk->sk_state = IUCV_CLOSED;
433 		sk->sk_state_change(sk);
434 
435 		sk->sk_err = ECONNRESET;
436 		sk->sk_state_change(sk);
437 
438 		skb_queue_purge(&iucv->send_skb_q);
439 		skb_queue_purge(&iucv->backlog_skb_q);
440 		fallthrough;
441 
442 	default:
443 		iucv_sever_path(sk, 1);
444 	}
445 
446 	if (iucv->hs_dev) {
447 		dev_put(iucv->hs_dev);
448 		iucv->hs_dev = NULL;
449 		sk->sk_bound_dev_if = 0;
450 	}
451 
452 	/* mark socket for deletion by iucv_sock_kill() */
453 	sock_set_flag(sk, SOCK_ZAPPED);
454 
455 	release_sock(sk);
456 }
457 
458 static void iucv_sock_init(struct sock *sk, struct sock *parent)
459 {
460 	if (parent) {
461 		sk->sk_type = parent->sk_type;
462 		security_sk_clone(parent, sk);
463 	}
464 }
465 
466 static struct sock *iucv_sock_alloc(struct socket *sock, int proto, gfp_t prio, int kern)
467 {
468 	struct sock *sk;
469 	struct iucv_sock *iucv;
470 
471 	sk = sk_alloc(&init_net, PF_IUCV, prio, &iucv_proto, kern);
472 	if (!sk)
473 		return NULL;
474 	iucv = iucv_sk(sk);
475 
476 	sock_init_data(sock, sk);
477 	INIT_LIST_HEAD(&iucv->accept_q);
478 	spin_lock_init(&iucv->accept_q_lock);
479 	skb_queue_head_init(&iucv->send_skb_q);
480 	INIT_LIST_HEAD(&iucv->message_q.list);
481 	spin_lock_init(&iucv->message_q.lock);
482 	skb_queue_head_init(&iucv->backlog_skb_q);
483 	iucv->send_tag = 0;
484 	atomic_set(&iucv->pendings, 0);
485 	iucv->flags = 0;
486 	iucv->msglimit = 0;
487 	atomic_set(&iucv->skbs_in_xmit, 0);
488 	atomic_set(&iucv->msg_sent, 0);
489 	atomic_set(&iucv->msg_recv, 0);
490 	iucv->path = NULL;
491 	iucv->sk_txnotify = afiucv_hs_callback_txnotify;
492 	memset(&iucv->init, 0, sizeof(iucv->init));
493 	if (pr_iucv)
494 		iucv->transport = AF_IUCV_TRANS_IUCV;
495 	else
496 		iucv->transport = AF_IUCV_TRANS_HIPER;
497 
498 	sk->sk_destruct = iucv_sock_destruct;
499 	sk->sk_sndtimeo = IUCV_CONN_TIMEOUT;
500 
501 	sock_reset_flag(sk, SOCK_ZAPPED);
502 
503 	sk->sk_protocol = proto;
504 	sk->sk_state	= IUCV_OPEN;
505 
506 	iucv_sock_link(&iucv_sk_list, sk);
507 	return sk;
508 }
509 
510 static void iucv_accept_enqueue(struct sock *parent, struct sock *sk)
511 {
512 	unsigned long flags;
513 	struct iucv_sock *par = iucv_sk(parent);
514 
515 	sock_hold(sk);
516 	spin_lock_irqsave(&par->accept_q_lock, flags);
517 	list_add_tail(&iucv_sk(sk)->accept_q, &par->accept_q);
518 	spin_unlock_irqrestore(&par->accept_q_lock, flags);
519 	iucv_sk(sk)->parent = parent;
520 	sk_acceptq_added(parent);
521 }
522 
523 static void iucv_accept_unlink(struct sock *sk)
524 {
525 	unsigned long flags;
526 	struct iucv_sock *par = iucv_sk(iucv_sk(sk)->parent);
527 
528 	spin_lock_irqsave(&par->accept_q_lock, flags);
529 	list_del_init(&iucv_sk(sk)->accept_q);
530 	spin_unlock_irqrestore(&par->accept_q_lock, flags);
531 	sk_acceptq_removed(iucv_sk(sk)->parent);
532 	iucv_sk(sk)->parent = NULL;
533 	sock_put(sk);
534 }
535 
536 static struct sock *iucv_accept_dequeue(struct sock *parent,
537 					struct socket *newsock)
538 {
539 	struct iucv_sock *isk, *n;
540 	struct sock *sk;
541 
542 	list_for_each_entry_safe(isk, n, &iucv_sk(parent)->accept_q, accept_q) {
543 		sk = (struct sock *) isk;
544 		lock_sock(sk);
545 
546 		if (sk->sk_state == IUCV_CLOSED) {
547 			iucv_accept_unlink(sk);
548 			release_sock(sk);
549 			continue;
550 		}
551 
552 		if (sk->sk_state == IUCV_CONNECTED ||
553 		    sk->sk_state == IUCV_DISCONN ||
554 		    !newsock) {
555 			iucv_accept_unlink(sk);
556 			if (newsock)
557 				sock_graft(sk, newsock);
558 
559 			release_sock(sk);
560 			return sk;
561 		}
562 
563 		release_sock(sk);
564 	}
565 	return NULL;
566 }
567 
568 static void __iucv_auto_name(struct iucv_sock *iucv)
569 {
570 	char name[12];
571 
572 	scnprintf(name, sizeof(name),
573 		  "%08x", atomic_inc_return(&iucv_sk_list.autobind_name));
574 	while (__iucv_get_sock_by_name(name)) {
575 		scnprintf(name, sizeof(name), "%08x",
576 			  atomic_inc_return(&iucv_sk_list.autobind_name));
577 	}
578 	memcpy(iucv->src_name, name, 8);
579 }
580 
581 /* Bind an unbound socket */
582 static int iucv_sock_bind(struct socket *sock, struct sockaddr_unsized *addr,
583 			  int addr_len)
584 {
585 	DECLARE_SOCKADDR(struct sockaddr_iucv *, sa, addr);
586 	char uid[sizeof(sa->siucv_user_id)];
587 	struct sock *sk = sock->sk;
588 	struct iucv_sock *iucv;
589 	int err = 0;
590 	struct net_device *dev;
591 
592 	/* Verify the input sockaddr */
593 	if (addr_len < sizeof(struct sockaddr_iucv) ||
594 	    addr->sa_family != AF_IUCV)
595 		return -EINVAL;
596 
597 	lock_sock(sk);
598 	if (sk->sk_state != IUCV_OPEN) {
599 		err = -EBADFD;
600 		goto done;
601 	}
602 
603 	write_lock_bh(&iucv_sk_list.lock);
604 
605 	iucv = iucv_sk(sk);
606 	if (__iucv_get_sock_by_name(sa->siucv_name)) {
607 		err = -EADDRINUSE;
608 		goto done_unlock;
609 	}
610 	if (iucv->path)
611 		goto done_unlock;
612 
613 	/* Bind the socket */
614 	if (pr_iucv)
615 		if (!memcmp(sa->siucv_user_id, iucv_userid, 8))
616 			goto vm_bind; /* VM IUCV transport */
617 
618 	/* try hiper transport */
619 	memcpy(uid, sa->siucv_user_id, sizeof(uid));
620 	ASCEBC(uid, 8);
621 	rcu_read_lock();
622 	for_each_netdev_rcu(&init_net, dev) {
623 		if (!memcmp(dev->perm_addr, uid, 8)) {
624 			memcpy(iucv->src_user_id, sa->siucv_user_id, 8);
625 			/* Check for uninitialized siucv_name */
626 			if (strncmp(sa->siucv_name, "        ", 8) == 0)
627 				__iucv_auto_name(iucv);
628 			else
629 				memcpy(iucv->src_name, sa->siucv_name, 8);
630 			sk->sk_bound_dev_if = dev->ifindex;
631 			iucv->hs_dev = dev;
632 			dev_hold(dev);
633 			sk->sk_state = IUCV_BOUND;
634 			iucv->transport = AF_IUCV_TRANS_HIPER;
635 			if (!iucv->msglimit)
636 				iucv->msglimit = IUCV_HIPER_MSGLIM_DEFAULT;
637 			rcu_read_unlock();
638 			goto done_unlock;
639 		}
640 	}
641 	rcu_read_unlock();
642 vm_bind:
643 	if (pr_iucv) {
644 		/* use local userid for backward compat */
645 		memcpy(iucv->src_name, sa->siucv_name, 8);
646 		memcpy(iucv->src_user_id, iucv_userid, 8);
647 		sk->sk_state = IUCV_BOUND;
648 		iucv->transport = AF_IUCV_TRANS_IUCV;
649 		sk->sk_allocation |= GFP_DMA;
650 		if (!iucv->msglimit)
651 			iucv->msglimit = IUCV_QUEUELEN_DEFAULT;
652 		goto done_unlock;
653 	}
654 	/* found no dev to bind */
655 	err = -ENODEV;
656 done_unlock:
657 	/* Release the socket list lock */
658 	write_unlock_bh(&iucv_sk_list.lock);
659 done:
660 	release_sock(sk);
661 	return err;
662 }
663 
664 /* Automatically bind an unbound socket */
665 static int iucv_sock_autobind(struct sock *sk)
666 {
667 	struct iucv_sock *iucv = iucv_sk(sk);
668 	int err = 0;
669 
670 	if (unlikely(!pr_iucv))
671 		return -EPROTO;
672 
673 	memcpy(iucv->src_user_id, iucv_userid, 8);
674 	iucv->transport = AF_IUCV_TRANS_IUCV;
675 	sk->sk_allocation |= GFP_DMA;
676 
677 	write_lock_bh(&iucv_sk_list.lock);
678 	__iucv_auto_name(iucv);
679 	write_unlock_bh(&iucv_sk_list.lock);
680 
681 	if (!iucv->msglimit)
682 		iucv->msglimit = IUCV_QUEUELEN_DEFAULT;
683 
684 	return err;
685 }
686 
687 static int afiucv_path_connect(struct socket *sock, struct sockaddr_unsized *addr)
688 {
689 	DECLARE_SOCKADDR(struct sockaddr_iucv *, sa, addr);
690 	struct sock *sk = sock->sk;
691 	struct iucv_sock *iucv = iucv_sk(sk);
692 	unsigned char user_data[16];
693 	int err;
694 
695 	high_nmcpy(user_data, sa->siucv_name);
696 	low_nmcpy(user_data, iucv->src_name);
697 	ASCEBC(user_data, sizeof(user_data));
698 
699 	/* Create path. */
700 	iucv->path = iucv_path_alloc(iucv->msglimit,
701 				     IUCV_IPRMDATA, GFP_KERNEL);
702 	if (!iucv->path) {
703 		err = -ENOMEM;
704 		goto done;
705 	}
706 	err = pr_iucv->path_connect(iucv->path, &af_iucv_handler,
707 				    sa->siucv_user_id, NULL, user_data,
708 				    sk);
709 	if (err) {
710 		iucv_path_free(iucv->path);
711 		iucv->path = NULL;
712 		switch (err) {
713 		case 0x0b:	/* Target communicator is not logged on */
714 			err = -ENETUNREACH;
715 			break;
716 		case 0x0d:	/* Max connections for this guest exceeded */
717 		case 0x0e:	/* Max connections for target guest exceeded */
718 			err = -EAGAIN;
719 			break;
720 		case 0x0f:	/* Missing IUCV authorization */
721 			err = -EACCES;
722 			break;
723 		default:
724 			err = -ECONNREFUSED;
725 			break;
726 		}
727 	}
728 done:
729 	return err;
730 }
731 
732 /* Connect an unconnected socket */
733 static int iucv_sock_connect(struct socket *sock, struct sockaddr_unsized *addr,
734 			     int alen, int flags)
735 {
736 	DECLARE_SOCKADDR(struct sockaddr_iucv *, sa, addr);
737 	struct sock *sk = sock->sk;
738 	struct iucv_sock *iucv = iucv_sk(sk);
739 	int err;
740 
741 	if (alen < sizeof(struct sockaddr_iucv) || addr->sa_family != AF_IUCV)
742 		return -EINVAL;
743 
744 	if (sk->sk_state != IUCV_OPEN && sk->sk_state != IUCV_BOUND)
745 		return -EBADFD;
746 
747 	if (sk->sk_state == IUCV_OPEN &&
748 	    iucv->transport == AF_IUCV_TRANS_HIPER)
749 		return -EBADFD; /* explicit bind required */
750 
751 	if (sk->sk_type != SOCK_STREAM && sk->sk_type != SOCK_SEQPACKET)
752 		return -EINVAL;
753 
754 	if (sk->sk_state == IUCV_OPEN) {
755 		err = iucv_sock_autobind(sk);
756 		if (unlikely(err))
757 			return err;
758 	}
759 
760 	lock_sock(sk);
761 
762 	/* Set the destination information */
763 	memcpy(iucv->dst_user_id, sa->siucv_user_id, 8);
764 	memcpy(iucv->dst_name, sa->siucv_name, 8);
765 
766 	if (iucv->transport == AF_IUCV_TRANS_HIPER)
767 		err = iucv_send_ctrl(sock->sk, AF_IUCV_FLAG_SYN);
768 	else
769 		err = afiucv_path_connect(sock, addr);
770 	if (err)
771 		goto done;
772 
773 	if (sk->sk_state != IUCV_CONNECTED)
774 		err = iucv_sock_wait(sk, iucv_sock_in_state(sk, IUCV_CONNECTED,
775 							    IUCV_DISCONN),
776 				     sock_sndtimeo(sk, flags & O_NONBLOCK));
777 
778 	if (sk->sk_state == IUCV_DISCONN || sk->sk_state == IUCV_CLOSED)
779 		err = -ECONNREFUSED;
780 
781 	if (err && iucv->transport == AF_IUCV_TRANS_IUCV)
782 		iucv_sever_path(sk, 0);
783 
784 done:
785 	release_sock(sk);
786 	return err;
787 }
788 
789 /* Move a socket into listening state. */
790 static int iucv_sock_listen(struct socket *sock, int backlog)
791 {
792 	struct sock *sk = sock->sk;
793 	int err;
794 
795 	lock_sock(sk);
796 
797 	err = -EINVAL;
798 	if (sk->sk_state != IUCV_BOUND)
799 		goto done;
800 
801 	if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
802 		goto done;
803 
804 	sk->sk_max_ack_backlog = backlog;
805 	sk->sk_ack_backlog = 0;
806 	sk->sk_state = IUCV_LISTEN;
807 	err = 0;
808 
809 done:
810 	release_sock(sk);
811 	return err;
812 }
813 
814 /* Accept a pending connection */
815 static int iucv_sock_accept(struct socket *sock, struct socket *newsock,
816 			    struct proto_accept_arg *arg)
817 {
818 	DECLARE_WAITQUEUE(wait, current);
819 	struct sock *sk = sock->sk, *nsk;
820 	long timeo;
821 	int err = 0;
822 
823 	lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
824 
825 	if (sk->sk_state != IUCV_LISTEN) {
826 		err = -EBADFD;
827 		goto done;
828 	}
829 
830 	timeo = sock_rcvtimeo(sk, arg->flags & O_NONBLOCK);
831 
832 	/* Wait for an incoming connection */
833 	add_wait_queue_exclusive(sk_sleep(sk), &wait);
834 	while (!(nsk = iucv_accept_dequeue(sk, newsock))) {
835 		set_current_state(TASK_INTERRUPTIBLE);
836 		if (!timeo) {
837 			err = -EAGAIN;
838 			break;
839 		}
840 
841 		release_sock(sk);
842 		timeo = schedule_timeout(timeo);
843 		lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
844 
845 		if (sk->sk_state != IUCV_LISTEN) {
846 			err = -EBADFD;
847 			break;
848 		}
849 
850 		if (signal_pending(current)) {
851 			err = sock_intr_errno(timeo);
852 			break;
853 		}
854 	}
855 
856 	set_current_state(TASK_RUNNING);
857 	remove_wait_queue(sk_sleep(sk), &wait);
858 
859 	if (err)
860 		goto done;
861 
862 	newsock->state = SS_CONNECTED;
863 
864 done:
865 	release_sock(sk);
866 	return err;
867 }
868 
869 static int iucv_sock_getname(struct socket *sock, struct sockaddr *addr,
870 			     int peer)
871 {
872 	DECLARE_SOCKADDR(struct sockaddr_iucv *, siucv, addr);
873 	struct sock *sk = sock->sk;
874 	struct iucv_sock *iucv = iucv_sk(sk);
875 
876 	addr->sa_family = AF_IUCV;
877 
878 	if (peer) {
879 		memcpy(siucv->siucv_user_id, iucv->dst_user_id, 8);
880 		memcpy(siucv->siucv_name, iucv->dst_name, 8);
881 	} else {
882 		memcpy(siucv->siucv_user_id, iucv->src_user_id, 8);
883 		memcpy(siucv->siucv_name, iucv->src_name, 8);
884 	}
885 	memset(&siucv->siucv_port, 0, sizeof(siucv->siucv_port));
886 	memset(&siucv->siucv_addr, 0, sizeof(siucv->siucv_addr));
887 	memset(&siucv->siucv_nodeid, 0, sizeof(siucv->siucv_nodeid));
888 
889 	return sizeof(struct sockaddr_iucv);
890 }
891 
892 /**
893  * iucv_send_iprm() - Send socket data in parameter list of an iucv message.
894  * @path:	IUCV path
895  * @msg:	Pointer to a struct iucv_message
896  * @skb:	The socket data to send, skb->len MUST BE <= 7
897  *
898  * Send the socket data in the parameter list in the iucv message
899  * (IUCV_IPRMDATA). The socket data is stored at index 0 to 6 in the parameter
900  * list and the socket data len at index 7 (last byte).
901  * See also iucv_msg_length().
902  *
903  * Returns: the return code from the iucv_message_send() call.
904  */
905 static int iucv_send_iprm(struct iucv_path *path, struct iucv_message *msg,
906 			  struct sk_buff *skb)
907 {
908 	u8 prmdata[8];
909 
910 	memcpy(prmdata, (void *) skb->data, skb->len);
911 	prmdata[7] = 0xff - (u8) skb->len;
912 	return pr_iucv->message_send(path, msg, IUCV_IPRMDATA, 0,
913 				 (void *) prmdata, 8);
914 }
915 
916 static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg,
917 			     size_t len)
918 {
919 	struct sock *sk = sock->sk;
920 	struct iucv_sock *iucv = iucv_sk(sk);
921 	size_t headroom = 0;
922 	size_t linear;
923 	struct sk_buff *skb;
924 	struct iucv_message txmsg = {0};
925 	struct cmsghdr *cmsg;
926 	int cmsg_done;
927 	long timeo;
928 	char user_id[9];
929 	char appl_id[9];
930 	int err;
931 	int noblock = msg->msg_flags & MSG_DONTWAIT;
932 
933 	err = sock_error(sk);
934 	if (err)
935 		return err;
936 
937 	if (msg->msg_flags & MSG_OOB)
938 		return -EOPNOTSUPP;
939 
940 	/* SOCK_SEQPACKET: we do not support segmented records */
941 	if (sk->sk_type == SOCK_SEQPACKET && !(msg->msg_flags & MSG_EOR))
942 		return -EOPNOTSUPP;
943 
944 	lock_sock(sk);
945 
946 	if (sk->sk_shutdown & SEND_SHUTDOWN) {
947 		err = -EPIPE;
948 		goto out;
949 	}
950 
951 	/* Return if the socket is not in connected state */
952 	if (sk->sk_state != IUCV_CONNECTED) {
953 		err = -ENOTCONN;
954 		goto out;
955 	}
956 
957 	/* initialize defaults */
958 	cmsg_done   = 0;	/* check for duplicate headers */
959 
960 	/* iterate over control messages */
961 	for_each_cmsghdr(cmsg, msg) {
962 		if (!CMSG_OK(msg, cmsg)) {
963 			err = -EINVAL;
964 			goto out;
965 		}
966 
967 		if (cmsg->cmsg_level != SOL_IUCV)
968 			continue;
969 
970 		if (cmsg->cmsg_type & cmsg_done) {
971 			err = -EINVAL;
972 			goto out;
973 		}
974 		cmsg_done |= cmsg->cmsg_type;
975 
976 		switch (cmsg->cmsg_type) {
977 		case SCM_IUCV_TRGCLS:
978 			if (cmsg->cmsg_len != CMSG_LEN(TRGCLS_SIZE)) {
979 				err = -EINVAL;
980 				goto out;
981 			}
982 
983 			/* set iucv message target class */
984 			memcpy(&txmsg.class,
985 				(void *) CMSG_DATA(cmsg), TRGCLS_SIZE);
986 
987 			break;
988 
989 		default:
990 			err = -EINVAL;
991 			goto out;
992 		}
993 	}
994 
995 	/* allocate one skb for each iucv message:
996 	 * this is fine for SOCK_SEQPACKET (unless we want to support
997 	 * segmented records using the MSG_EOR flag), but
998 	 * for SOCK_STREAM we might want to improve it in future */
999 	if (iucv->transport == AF_IUCV_TRANS_HIPER) {
1000 		headroom = sizeof(struct af_iucv_trans_hdr) +
1001 			   LL_RESERVED_SPACE(iucv->hs_dev);
1002 		linear = min(len, PAGE_SIZE - headroom);
1003 	} else {
1004 		if (len < PAGE_SIZE) {
1005 			linear = len;
1006 		} else {
1007 			/* In nonlinear "classic" iucv skb,
1008 			 * reserve space for iucv_array
1009 			 */
1010 			headroom = sizeof(struct iucv_array) *
1011 				   (MAX_SKB_FRAGS + 1);
1012 			linear = PAGE_SIZE - headroom;
1013 		}
1014 	}
1015 	skb = sock_alloc_send_pskb(sk, headroom + linear, len - linear,
1016 				   noblock, &err, 0);
1017 	if (!skb)
1018 		goto out;
1019 	if (headroom)
1020 		skb_reserve(skb, headroom);
1021 	skb_put(skb, linear);
1022 	skb->len = len;
1023 	skb->data_len = len - linear;
1024 	err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
1025 	if (err)
1026 		goto fail;
1027 
1028 	/* wait if outstanding messages for iucv path has reached */
1029 	timeo = sock_sndtimeo(sk, noblock);
1030 	err = iucv_sock_wait(sk, iucv_below_msglim(sk), timeo);
1031 	if (err)
1032 		goto fail;
1033 
1034 	/* return -ECONNRESET if the socket is no longer connected */
1035 	if (sk->sk_state != IUCV_CONNECTED) {
1036 		err = -ECONNRESET;
1037 		goto fail;
1038 	}
1039 
1040 	/* increment and save iucv message tag for msg_completion cbk */
1041 	txmsg.tag = iucv->send_tag++;
1042 	IUCV_SKB_CB(skb)->tag = txmsg.tag;
1043 
1044 	if (iucv->transport == AF_IUCV_TRANS_HIPER) {
1045 		atomic_inc(&iucv->msg_sent);
1046 		err = afiucv_hs_send(&txmsg, sk, skb, 0);
1047 		if (err) {
1048 			atomic_dec(&iucv->msg_sent);
1049 			goto out;
1050 		}
1051 	} else { /* Classic VM IUCV transport */
1052 		skb_queue_tail(&iucv->send_skb_q, skb);
1053 		atomic_inc(&iucv->skbs_in_xmit);
1054 
1055 		if (((iucv->path->flags & IUCV_IPRMDATA) & iucv->flags) &&
1056 		    skb->len <= 7) {
1057 			err = iucv_send_iprm(iucv->path, &txmsg, skb);
1058 
1059 			/* on success: there is no message_complete callback */
1060 			/* for an IPRMDATA msg; remove skb from send queue   */
1061 			if (err == 0) {
1062 				atomic_dec(&iucv->skbs_in_xmit);
1063 				skb_unlink(skb, &iucv->send_skb_q);
1064 				consume_skb(skb);
1065 			}
1066 
1067 			/* this error should never happen since the	*/
1068 			/* IUCV_IPRMDATA path flag is set... sever path */
1069 			if (err == 0x15) {
1070 				pr_iucv->path_sever(iucv->path, NULL);
1071 				atomic_dec(&iucv->skbs_in_xmit);
1072 				skb_unlink(skb, &iucv->send_skb_q);
1073 				err = -EPIPE;
1074 				goto fail;
1075 			}
1076 		} else if (skb_is_nonlinear(skb)) {
1077 			struct iucv_array *iba = (struct iucv_array *)skb->head;
1078 			int i;
1079 
1080 			/* skip iucv_array lying in the headroom */
1081 			iba[0].address = virt_to_dma32(skb->data);
1082 			iba[0].length = (u32)skb_headlen(skb);
1083 			for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1084 				skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1085 
1086 				iba[i + 1].address = virt_to_dma32(skb_frag_address(frag));
1087 				iba[i + 1].length = (u32)skb_frag_size(frag);
1088 			}
1089 			err = pr_iucv->message_send(iucv->path, &txmsg,
1090 						    IUCV_IPBUFLST, 0,
1091 						    (void *)iba, skb->len);
1092 		} else { /* non-IPRM Linear skb */
1093 			err = pr_iucv->message_send(iucv->path, &txmsg,
1094 					0, 0, (void *)skb->data, skb->len);
1095 		}
1096 		if (err) {
1097 			if (err == 3) {
1098 				user_id[8] = 0;
1099 				memcpy(user_id, iucv->dst_user_id, 8);
1100 				appl_id[8] = 0;
1101 				memcpy(appl_id, iucv->dst_name, 8);
1102 				pr_err(
1103 		"Application %s on z/VM guest %s exceeds message limit\n",
1104 					appl_id, user_id);
1105 				err = -EAGAIN;
1106 			} else {
1107 				err = -EPIPE;
1108 			}
1109 
1110 			atomic_dec(&iucv->skbs_in_xmit);
1111 			skb_unlink(skb, &iucv->send_skb_q);
1112 			goto fail;
1113 		}
1114 	}
1115 
1116 	release_sock(sk);
1117 	return len;
1118 
1119 fail:
1120 	kfree_skb(skb);
1121 out:
1122 	release_sock(sk);
1123 	return err;
1124 }
1125 
1126 static struct sk_buff *alloc_iucv_recv_skb(unsigned long len)
1127 {
1128 	size_t headroom, linear;
1129 	struct sk_buff *skb;
1130 	int err;
1131 
1132 	if (len < PAGE_SIZE) {
1133 		headroom = 0;
1134 		linear = len;
1135 	} else {
1136 		headroom = sizeof(struct iucv_array) * (MAX_SKB_FRAGS + 1);
1137 		linear = PAGE_SIZE - headroom;
1138 	}
1139 	skb = alloc_skb_with_frags(headroom + linear, len - linear,
1140 				   0, &err, GFP_ATOMIC | GFP_DMA);
1141 	WARN_ONCE(!skb,
1142 		  "alloc of recv iucv skb len=%lu failed with errcode=%d\n",
1143 		  len, err);
1144 	if (skb) {
1145 		if (headroom)
1146 			skb_reserve(skb, headroom);
1147 		skb_put(skb, linear);
1148 		skb->len = len;
1149 		skb->data_len = len - linear;
1150 	}
1151 	return skb;
1152 }
1153 
1154 /* iucv_process_message() - Receive a single outstanding IUCV message
1155  *
1156  * Locking: must be called with message_q.lock held
1157  */
1158 static void iucv_process_message(struct sock *sk, struct sk_buff *skb,
1159 				 struct iucv_path *path,
1160 				 struct iucv_message *msg)
1161 {
1162 	int rc;
1163 	unsigned int len;
1164 
1165 	len = iucv_msg_length(msg);
1166 
1167 	/* store msg target class in the second 4 bytes of skb ctrl buffer */
1168 	/* Note: the first 4 bytes are reserved for msg tag */
1169 	IUCV_SKB_CB(skb)->class = msg->class;
1170 
1171 	/* check for special IPRM messages (e.g. iucv_sock_shutdown) */
1172 	if ((msg->flags & IUCV_IPRMDATA) && len > 7) {
1173 		if (memcmp(msg->rmmsg, iprm_shutdown, 8) == 0) {
1174 			skb->data = NULL;
1175 			skb->len = 0;
1176 		}
1177 	} else {
1178 		if (skb_is_nonlinear(skb)) {
1179 			struct iucv_array *iba = (struct iucv_array *)skb->head;
1180 			int i;
1181 
1182 			iba[0].address = virt_to_dma32(skb->data);
1183 			iba[0].length = (u32)skb_headlen(skb);
1184 			for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1185 				skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1186 
1187 				iba[i + 1].address = virt_to_dma32(skb_frag_address(frag));
1188 				iba[i + 1].length = (u32)skb_frag_size(frag);
1189 			}
1190 			rc = pr_iucv->message_receive(path, msg,
1191 					      IUCV_IPBUFLST,
1192 					      (void *)iba, len, NULL);
1193 		} else {
1194 			rc = pr_iucv->message_receive(path, msg,
1195 					      msg->flags & IUCV_IPRMDATA,
1196 					      skb->data, len, NULL);
1197 		}
1198 		if (rc) {
1199 			kfree_skb(skb);
1200 			return;
1201 		}
1202 		WARN_ON_ONCE(skb->len != len);
1203 	}
1204 
1205 	IUCV_SKB_CB(skb)->offset = 0;
1206 	if (sk_filter(sk, skb)) {
1207 		sk_drops_inc(sk);	/* skb rejected by filter */
1208 		kfree_skb(skb);
1209 		return;
1210 	}
1211 	if (__sock_queue_rcv_skb(sk, skb))	/* handle rcv queue full */
1212 		skb_queue_tail(&iucv_sk(sk)->backlog_skb_q, skb);
1213 }
1214 
1215 /* iucv_process_message_q() - Process outstanding IUCV messages
1216  *
1217  * Locking: must be called with message_q.lock held
1218  */
1219 static void iucv_process_message_q(struct sock *sk)
1220 {
1221 	struct iucv_sock *iucv = iucv_sk(sk);
1222 	struct sk_buff *skb;
1223 	struct sock_msg_q *p, *n;
1224 
1225 	list_for_each_entry_safe(p, n, &iucv->message_q.list, list) {
1226 		skb = alloc_iucv_recv_skb(iucv_msg_length(&p->msg));
1227 		if (!skb)
1228 			break;
1229 		iucv_process_message(sk, skb, p->path, &p->msg);
1230 		list_del(&p->list);
1231 		kfree(p);
1232 		if (!skb_queue_empty(&iucv->backlog_skb_q))
1233 			break;
1234 	}
1235 }
1236 
1237 static int iucv_sock_recvmsg(struct socket *sock, struct msghdr *msg,
1238 			     size_t len, int flags)
1239 {
1240 	struct sock *sk = sock->sk;
1241 	struct iucv_sock *iucv = iucv_sk(sk);
1242 	unsigned int copied, rlen;
1243 	struct sk_buff *skb, *rskb, *cskb;
1244 	int err = 0;
1245 	u32 offset;
1246 
1247 	if ((sk->sk_state == IUCV_DISCONN) &&
1248 	    skb_queue_empty(&iucv->backlog_skb_q) &&
1249 	    skb_queue_empty(&sk->sk_receive_queue) &&
1250 	    list_empty(&iucv->message_q.list))
1251 		return 0;
1252 
1253 	if (flags & (MSG_OOB))
1254 		return -EOPNOTSUPP;
1255 
1256 	/* receive/dequeue next skb:
1257 	 * the function understands MSG_PEEK and, thus, does not dequeue skb
1258 	 * only refcount is increased.
1259 	 */
1260 	skb = skb_recv_datagram(sk, flags, &err);
1261 	if (!skb) {
1262 		if (sk->sk_shutdown & RCV_SHUTDOWN)
1263 			return 0;
1264 		return err;
1265 	}
1266 
1267 	offset = IUCV_SKB_CB(skb)->offset;
1268 	rlen   = skb->len - offset;		/* real length of skb */
1269 	copied = min_t(unsigned int, rlen, len);
1270 	if (!rlen)
1271 		sk->sk_shutdown = sk->sk_shutdown | RCV_SHUTDOWN;
1272 
1273 	cskb = skb;
1274 	if (skb_copy_datagram_msg(cskb, offset, msg, copied)) {
1275 		err = -EFAULT;
1276 		goto err_out;
1277 	}
1278 
1279 	/* SOCK_SEQPACKET: set MSG_TRUNC if recv buf size is too small */
1280 	if (sk->sk_type == SOCK_SEQPACKET) {
1281 		if (copied < rlen)
1282 			msg->msg_flags |= MSG_TRUNC;
1283 		/* each iucv message contains a complete record */
1284 		msg->msg_flags |= MSG_EOR;
1285 	}
1286 
1287 	/* create control message to store iucv msg target class:
1288 	 * get the trgcls from the control buffer of the skb due to
1289 	 * fragmentation of original iucv message. */
1290 	err = put_cmsg(msg, SOL_IUCV, SCM_IUCV_TRGCLS,
1291 		       sizeof(IUCV_SKB_CB(skb)->class),
1292 		       (void *)&IUCV_SKB_CB(skb)->class);
1293 	if (err)
1294 		goto err_out;
1295 
1296 	/* Mark read part of skb as used */
1297 	if (!(flags & MSG_PEEK)) {
1298 
1299 		/* SOCK_STREAM: re-queue skb if it contains unreceived data */
1300 		if (sk->sk_type == SOCK_STREAM) {
1301 			if (copied < rlen) {
1302 				IUCV_SKB_CB(skb)->offset = offset + copied;
1303 				skb_queue_head(&sk->sk_receive_queue, skb);
1304 				goto done;
1305 			}
1306 		}
1307 
1308 		consume_skb(skb);
1309 		if (iucv->transport == AF_IUCV_TRANS_HIPER) {
1310 			atomic_inc(&iucv->msg_recv);
1311 			if (atomic_read(&iucv->msg_recv) > iucv->msglimit) {
1312 				WARN_ON(1);
1313 				iucv_sock_close(sk);
1314 				return -EFAULT;
1315 			}
1316 		}
1317 
1318 		/* Queue backlog skbs */
1319 		spin_lock_bh(&iucv->message_q.lock);
1320 		rskb = skb_dequeue(&iucv->backlog_skb_q);
1321 		while (rskb) {
1322 			IUCV_SKB_CB(rskb)->offset = 0;
1323 			if (__sock_queue_rcv_skb(sk, rskb)) {
1324 				/* handle rcv queue full */
1325 				skb_queue_head(&iucv->backlog_skb_q,
1326 						rskb);
1327 				break;
1328 			}
1329 			rskb = skb_dequeue(&iucv->backlog_skb_q);
1330 		}
1331 		if (skb_queue_empty(&iucv->backlog_skb_q)) {
1332 			if (!list_empty(&iucv->message_q.list))
1333 				iucv_process_message_q(sk);
1334 			if (atomic_read(&iucv->msg_recv) >=
1335 							iucv->msglimit / 2) {
1336 				err = iucv_send_ctrl(sk, AF_IUCV_FLAG_WIN);
1337 				if (err) {
1338 					sk->sk_state = IUCV_DISCONN;
1339 					sk->sk_state_change(sk);
1340 				}
1341 			}
1342 		}
1343 		spin_unlock_bh(&iucv->message_q.lock);
1344 	}
1345 
1346 done:
1347 	/* SOCK_SEQPACKET: return real length if MSG_TRUNC is set */
1348 	if (sk->sk_type == SOCK_SEQPACKET && (flags & MSG_TRUNC))
1349 		copied = rlen;
1350 	if (flags & MSG_PEEK)
1351 		skb_unref(skb);
1352 
1353 	return copied;
1354 
1355 err_out:
1356 	if (!(flags & MSG_PEEK))
1357 		skb_queue_head(&sk->sk_receive_queue, skb);
1358 	else
1359 		skb_unref(skb);
1360 
1361 	return err;
1362 }
1363 
1364 static inline __poll_t iucv_accept_poll(struct sock *parent)
1365 {
1366 	struct iucv_sock *isk, *n;
1367 	struct sock *sk;
1368 
1369 	list_for_each_entry_safe(isk, n, &iucv_sk(parent)->accept_q, accept_q) {
1370 		sk = (struct sock *) isk;
1371 
1372 		if (sk->sk_state == IUCV_CONNECTED)
1373 			return EPOLLIN | EPOLLRDNORM;
1374 	}
1375 
1376 	return 0;
1377 }
1378 
1379 static __poll_t iucv_sock_poll(struct file *file, struct socket *sock,
1380 			       poll_table *wait)
1381 {
1382 	struct sock *sk = sock->sk;
1383 	__poll_t mask = 0;
1384 
1385 	sock_poll_wait(file, sock, wait);
1386 
1387 	if (sk->sk_state == IUCV_LISTEN)
1388 		return iucv_accept_poll(sk);
1389 
1390 	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
1391 		mask |= EPOLLERR |
1392 			(sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
1393 
1394 	if (sk->sk_shutdown & RCV_SHUTDOWN)
1395 		mask |= EPOLLRDHUP;
1396 
1397 	if (sk->sk_shutdown == SHUTDOWN_MASK)
1398 		mask |= EPOLLHUP;
1399 
1400 	if (!skb_queue_empty(&sk->sk_receive_queue) ||
1401 	    (sk->sk_shutdown & RCV_SHUTDOWN))
1402 		mask |= EPOLLIN | EPOLLRDNORM;
1403 
1404 	if (sk->sk_state == IUCV_CLOSED)
1405 		mask |= EPOLLHUP;
1406 
1407 	if (sk->sk_state == IUCV_DISCONN)
1408 		mask |= EPOLLIN;
1409 
1410 	if (sock_writeable(sk) && iucv_below_msglim(sk))
1411 		mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
1412 	else
1413 		sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
1414 
1415 	return mask;
1416 }
1417 
1418 static int iucv_sock_shutdown(struct socket *sock, int how)
1419 {
1420 	struct sock *sk = sock->sk;
1421 	struct iucv_sock *iucv = iucv_sk(sk);
1422 	struct iucv_message txmsg;
1423 	int err = 0;
1424 
1425 	how++;
1426 
1427 	if ((how & ~SHUTDOWN_MASK) || !how)
1428 		return -EINVAL;
1429 
1430 	lock_sock(sk);
1431 	switch (sk->sk_state) {
1432 	case IUCV_LISTEN:
1433 	case IUCV_DISCONN:
1434 	case IUCV_CLOSING:
1435 	case IUCV_CLOSED:
1436 		err = -ENOTCONN;
1437 		goto fail;
1438 	default:
1439 		break;
1440 	}
1441 
1442 	if ((how == SEND_SHUTDOWN || how == SHUTDOWN_MASK) &&
1443 	    sk->sk_state == IUCV_CONNECTED) {
1444 		if (iucv->transport == AF_IUCV_TRANS_IUCV) {
1445 			txmsg.class = 0;
1446 			txmsg.tag = 0;
1447 			err = pr_iucv->message_send(iucv->path, &txmsg,
1448 				IUCV_IPRMDATA, 0, (void *) iprm_shutdown, 8);
1449 			if (err) {
1450 				switch (err) {
1451 				case 1:
1452 					err = -ENOTCONN;
1453 					break;
1454 				case 2:
1455 					err = -ECONNRESET;
1456 					break;
1457 				default:
1458 					err = -ENOTCONN;
1459 					break;
1460 				}
1461 			}
1462 		} else
1463 			iucv_send_ctrl(sk, AF_IUCV_FLAG_SHT);
1464 	}
1465 
1466 	sk->sk_shutdown |= how;
1467 	if (how == RCV_SHUTDOWN || how == SHUTDOWN_MASK) {
1468 		if ((iucv->transport == AF_IUCV_TRANS_IUCV) &&
1469 		    iucv->path) {
1470 			err = pr_iucv->path_quiesce(iucv->path, NULL);
1471 			if (err)
1472 				err = -ENOTCONN;
1473 /*			skb_queue_purge(&sk->sk_receive_queue); */
1474 		}
1475 		skb_queue_purge(&sk->sk_receive_queue);
1476 	}
1477 
1478 	/* Wake up anyone sleeping in poll */
1479 	sk->sk_state_change(sk);
1480 
1481 fail:
1482 	release_sock(sk);
1483 	return err;
1484 }
1485 
1486 static int iucv_sock_release(struct socket *sock)
1487 {
1488 	struct sock *sk = sock->sk;
1489 	int err = 0;
1490 
1491 	if (!sk)
1492 		return 0;
1493 
1494 	iucv_sock_close(sk);
1495 
1496 	sock_orphan(sk);
1497 	iucv_sock_kill(sk);
1498 	return err;
1499 }
1500 
1501 /* getsockopt and setsockopt */
1502 static int iucv_sock_setsockopt(struct socket *sock, int level, int optname,
1503 				sockptr_t optval, unsigned int optlen)
1504 {
1505 	struct sock *sk = sock->sk;
1506 	struct iucv_sock *iucv = iucv_sk(sk);
1507 	int val;
1508 	int rc;
1509 
1510 	if (level != SOL_IUCV)
1511 		return -ENOPROTOOPT;
1512 
1513 	if (optlen < sizeof(int))
1514 		return -EINVAL;
1515 
1516 	if (copy_from_sockptr(&val, optval, sizeof(int)))
1517 		return -EFAULT;
1518 
1519 	rc = 0;
1520 
1521 	lock_sock(sk);
1522 	switch (optname) {
1523 	case SO_IPRMDATA_MSG:
1524 		if (val)
1525 			iucv->flags |= IUCV_IPRMDATA;
1526 		else
1527 			iucv->flags &= ~IUCV_IPRMDATA;
1528 		break;
1529 	case SO_MSGLIMIT:
1530 		switch (sk->sk_state) {
1531 		case IUCV_OPEN:
1532 		case IUCV_BOUND:
1533 			if (val < 1 || val > U16_MAX)
1534 				rc = -EINVAL;
1535 			else
1536 				iucv->msglimit = val;
1537 			break;
1538 		default:
1539 			rc = -EINVAL;
1540 			break;
1541 		}
1542 		break;
1543 	default:
1544 		rc = -ENOPROTOOPT;
1545 		break;
1546 	}
1547 	release_sock(sk);
1548 
1549 	return rc;
1550 }
1551 
1552 static int iucv_sock_getsockopt(struct socket *sock, int level, int optname,
1553 				sockopt_t *opt)
1554 {
1555 	struct sock *sk = sock->sk;
1556 	struct iucv_sock *iucv = iucv_sk(sk);
1557 	unsigned int val;
1558 	int len, rc;
1559 
1560 	if (level != SOL_IUCV)
1561 		return -ENOPROTOOPT;
1562 
1563 	len = opt->optlen;
1564 	if (len < 0)
1565 		return -EINVAL;
1566 
1567 	len = min_t(unsigned int, len, sizeof(int));
1568 
1569 	rc = 0;
1570 
1571 	lock_sock(sk);
1572 	switch (optname) {
1573 	case SO_IPRMDATA_MSG:
1574 		val = (iucv->flags & IUCV_IPRMDATA) ? 1 : 0;
1575 		break;
1576 	case SO_MSGLIMIT:
1577 		val = (iucv->path != NULL) ? iucv->path->msglim	/* connected */
1578 					   : iucv->msglimit;	/* default */
1579 		break;
1580 	case SO_MSGSIZE:
1581 		if (sk->sk_state == IUCV_OPEN) {
1582 			rc = -EBADFD;
1583 			break;
1584 		}
1585 		val = (iucv->hs_dev) ? iucv->hs_dev->mtu -
1586 				sizeof(struct af_iucv_trans_hdr) - ETH_HLEN :
1587 				0x7fffffff;
1588 		break;
1589 	default:
1590 		rc = -ENOPROTOOPT;
1591 		break;
1592 	}
1593 	release_sock(sk);
1594 
1595 	if (rc)
1596 		return rc;
1597 
1598 	opt->optlen = len;
1599 	if (copy_to_iter(&val, len, &opt->iter_out) != len)
1600 		return -EFAULT;
1601 
1602 	return 0;
1603 }
1604 
1605 
1606 /* Callback wrappers - called from iucv base support */
1607 static int iucv_callback_connreq(struct iucv_path *path,
1608 				 u8 ipvmid[8], u8 ipuser[16])
1609 {
1610 	unsigned char user_data[16];
1611 	unsigned char nuser_data[16];
1612 	unsigned char src_name[8];
1613 	struct sock *sk, *nsk;
1614 	struct iucv_sock *iucv, *niucv;
1615 	int err;
1616 
1617 	memcpy(src_name, ipuser, 8);
1618 	EBCASC(src_name, 8);
1619 	/* Find out if this path belongs to af_iucv. */
1620 	read_lock(&iucv_sk_list.lock);
1621 	iucv = NULL;
1622 	sk = NULL;
1623 	sk_for_each(sk, &iucv_sk_list.head)
1624 		if (sk->sk_state == IUCV_LISTEN &&
1625 		    !memcmp(&iucv_sk(sk)->src_name, src_name, 8)) {
1626 			/*
1627 			 * Found a listening socket with
1628 			 * src_name == ipuser[0-7].
1629 			 */
1630 			iucv = iucv_sk(sk);
1631 			break;
1632 		}
1633 	read_unlock(&iucv_sk_list.lock);
1634 	if (!iucv)
1635 		/* No socket found, not one of our paths. */
1636 		return -EINVAL;
1637 
1638 	bh_lock_sock(sk);
1639 
1640 	/* Check if parent socket is listening */
1641 	low_nmcpy(user_data, iucv->src_name);
1642 	high_nmcpy(user_data, iucv->dst_name);
1643 	ASCEBC(user_data, sizeof(user_data));
1644 	if (sk->sk_state != IUCV_LISTEN) {
1645 		err = pr_iucv->path_sever(path, user_data);
1646 		iucv_path_free(path);
1647 		goto fail;
1648 	}
1649 
1650 	/* Check for backlog size */
1651 	if (sk_acceptq_is_full(sk)) {
1652 		err = pr_iucv->path_sever(path, user_data);
1653 		iucv_path_free(path);
1654 		goto fail;
1655 	}
1656 
1657 	/* Create the new socket */
1658 	nsk = iucv_sock_alloc(NULL, sk->sk_protocol, GFP_ATOMIC, 0);
1659 	if (!nsk) {
1660 		err = pr_iucv->path_sever(path, user_data);
1661 		iucv_path_free(path);
1662 		goto fail;
1663 	}
1664 
1665 	niucv = iucv_sk(nsk);
1666 	iucv_sock_init(nsk, sk);
1667 	niucv->transport = AF_IUCV_TRANS_IUCV;
1668 	nsk->sk_allocation |= GFP_DMA;
1669 
1670 	/* Set the new iucv_sock */
1671 	memcpy(niucv->dst_name, ipuser + 8, 8);
1672 	EBCASC(niucv->dst_name, 8);
1673 	memcpy(niucv->dst_user_id, ipvmid, 8);
1674 	memcpy(niucv->src_name, iucv->src_name, 8);
1675 	memcpy(niucv->src_user_id, iucv->src_user_id, 8);
1676 	niucv->path = path;
1677 
1678 	/* Call iucv_accept */
1679 	high_nmcpy(nuser_data, ipuser + 8);
1680 	memcpy(nuser_data + 8, niucv->src_name, 8);
1681 	ASCEBC(nuser_data + 8, 8);
1682 
1683 	/* set message limit for path based on msglimit of accepting socket */
1684 	niucv->msglimit = iucv->msglimit;
1685 	path->msglim = iucv->msglimit;
1686 	err = pr_iucv->path_accept(path, &af_iucv_handler, nuser_data, nsk);
1687 	if (err) {
1688 		iucv_sever_path(nsk, 1);
1689 		iucv_sock_kill(nsk);
1690 		goto fail;
1691 	}
1692 
1693 	iucv_accept_enqueue(sk, nsk);
1694 
1695 	/* Wake up accept */
1696 	nsk->sk_state = IUCV_CONNECTED;
1697 	sk->sk_data_ready(sk);
1698 	err = 0;
1699 fail:
1700 	bh_unlock_sock(sk);
1701 	return 0;
1702 }
1703 
1704 static void iucv_callback_connack(struct iucv_path *path, u8 ipuser[16])
1705 {
1706 	struct sock *sk = path->private;
1707 
1708 	sk->sk_state = IUCV_CONNECTED;
1709 	sk->sk_state_change(sk);
1710 }
1711 
1712 static void iucv_callback_rx(struct iucv_path *path, struct iucv_message *msg)
1713 {
1714 	struct sock *sk = path->private;
1715 	struct iucv_sock *iucv = iucv_sk(sk);
1716 	struct sk_buff *skb;
1717 	struct sock_msg_q *save_msg;
1718 	int len;
1719 
1720 	if (sk->sk_shutdown & RCV_SHUTDOWN) {
1721 		pr_iucv->message_reject(path, msg);
1722 		return;
1723 	}
1724 
1725 	spin_lock(&iucv->message_q.lock);
1726 
1727 	if (!list_empty(&iucv->message_q.list) ||
1728 	    !skb_queue_empty(&iucv->backlog_skb_q))
1729 		goto save_message;
1730 
1731 	len = atomic_read(&sk->sk_rmem_alloc);
1732 	len += SKB_TRUESIZE(iucv_msg_length(msg));
1733 	if (len > sk->sk_rcvbuf)
1734 		goto save_message;
1735 
1736 	skb = alloc_iucv_recv_skb(iucv_msg_length(msg));
1737 	if (!skb)
1738 		goto save_message;
1739 
1740 	iucv_process_message(sk, skb, path, msg);
1741 	goto out_unlock;
1742 
1743 save_message:
1744 	save_msg = kzalloc_obj(struct sock_msg_q, GFP_ATOMIC | GFP_DMA);
1745 	if (!save_msg)
1746 		goto out_unlock;
1747 	save_msg->path = path;
1748 	save_msg->msg = *msg;
1749 
1750 	list_add_tail(&save_msg->list, &iucv->message_q.list);
1751 
1752 out_unlock:
1753 	spin_unlock(&iucv->message_q.lock);
1754 }
1755 
1756 static void iucv_callback_txdone(struct iucv_path *path,
1757 				 struct iucv_message *msg)
1758 {
1759 	struct sock *sk = path->private;
1760 	struct sk_buff *this = NULL;
1761 	struct sk_buff_head *list;
1762 	struct sk_buff *list_skb;
1763 	struct iucv_sock *iucv;
1764 	unsigned long flags;
1765 
1766 	iucv = iucv_sk(sk);
1767 	list = &iucv->send_skb_q;
1768 
1769 	bh_lock_sock(sk);
1770 
1771 	spin_lock_irqsave(&list->lock, flags);
1772 	skb_queue_walk(list, list_skb) {
1773 		if (msg->tag == IUCV_SKB_CB(list_skb)->tag) {
1774 			this = list_skb;
1775 			break;
1776 		}
1777 	}
1778 	if (this) {
1779 		atomic_dec(&iucv->skbs_in_xmit);
1780 		__skb_unlink(this, list);
1781 	}
1782 
1783 	spin_unlock_irqrestore(&list->lock, flags);
1784 
1785 	if (this) {
1786 		consume_skb(this);
1787 		/* wake up any process waiting for sending */
1788 		iucv_sock_wake_msglim(sk);
1789 	}
1790 
1791 	if (sk->sk_state == IUCV_CLOSING) {
1792 		if (atomic_read(&iucv->skbs_in_xmit) == 0) {
1793 			sk->sk_state = IUCV_CLOSED;
1794 			sk->sk_state_change(sk);
1795 		}
1796 	}
1797 	bh_unlock_sock(sk);
1798 
1799 }
1800 
1801 static void iucv_callback_connrej(struct iucv_path *path, u8 ipuser[16])
1802 {
1803 	struct sock *sk = path->private;
1804 
1805 	if (sk->sk_state == IUCV_CLOSED)
1806 		return;
1807 
1808 	bh_lock_sock(sk);
1809 	iucv_sever_path(sk, 1);
1810 	sk->sk_state = IUCV_DISCONN;
1811 
1812 	sk->sk_state_change(sk);
1813 	bh_unlock_sock(sk);
1814 }
1815 
1816 /* called if the other communication side shuts down its RECV direction;
1817  * in turn, the callback sets SEND_SHUTDOWN to disable sending of data.
1818  */
1819 static void iucv_callback_shutdown(struct iucv_path *path, u8 ipuser[16])
1820 {
1821 	struct sock *sk = path->private;
1822 
1823 	bh_lock_sock(sk);
1824 	if (sk->sk_state != IUCV_CLOSED) {
1825 		sk->sk_shutdown |= SEND_SHUTDOWN;
1826 		sk->sk_state_change(sk);
1827 	}
1828 	bh_unlock_sock(sk);
1829 }
1830 
1831 static struct iucv_handler af_iucv_handler = {
1832 	.path_pending		= iucv_callback_connreq,
1833 	.path_complete		= iucv_callback_connack,
1834 	.path_severed		= iucv_callback_connrej,
1835 	.message_pending	= iucv_callback_rx,
1836 	.message_complete	= iucv_callback_txdone,
1837 	.path_quiesced		= iucv_callback_shutdown,
1838 };
1839 
1840 /***************** HiperSockets transport callbacks ********************/
1841 static void afiucv_swap_src_dest(struct sk_buff *skb)
1842 {
1843 	struct af_iucv_trans_hdr *trans_hdr = iucv_trans_hdr(skb);
1844 	char tmpID[8];
1845 	char tmpName[8];
1846 
1847 	ASCEBC(trans_hdr->destUserID, sizeof(trans_hdr->destUserID));
1848 	ASCEBC(trans_hdr->destAppName, sizeof(trans_hdr->destAppName));
1849 	ASCEBC(trans_hdr->srcUserID, sizeof(trans_hdr->srcUserID));
1850 	ASCEBC(trans_hdr->srcAppName, sizeof(trans_hdr->srcAppName));
1851 	memcpy(tmpID, trans_hdr->srcUserID, 8);
1852 	memcpy(tmpName, trans_hdr->srcAppName, 8);
1853 	memcpy(trans_hdr->srcUserID, trans_hdr->destUserID, 8);
1854 	memcpy(trans_hdr->srcAppName, trans_hdr->destAppName, 8);
1855 	memcpy(trans_hdr->destUserID, tmpID, 8);
1856 	memcpy(trans_hdr->destAppName, tmpName, 8);
1857 	skb_push(skb, ETH_HLEN);
1858 	memset(skb->data, 0, ETH_HLEN);
1859 }
1860 
1861 /*
1862  * afiucv_hs_callback_syn - react on received SYN
1863  */
1864 static int afiucv_hs_callback_syn(struct sock *sk, struct sk_buff *skb)
1865 {
1866 	struct af_iucv_trans_hdr *trans_hdr = iucv_trans_hdr(skb);
1867 	struct sock *nsk;
1868 	struct iucv_sock *iucv, *niucv;
1869 	int err;
1870 
1871 	iucv = iucv_sk(sk);
1872 	if (!iucv) {
1873 		/* no sock - connection refused */
1874 		afiucv_swap_src_dest(skb);
1875 		trans_hdr->flags = AF_IUCV_FLAG_SYN | AF_IUCV_FLAG_FIN;
1876 		err = dev_queue_xmit(skb);
1877 		goto out;
1878 	}
1879 
1880 	nsk = iucv_sock_alloc(NULL, sk->sk_protocol, GFP_ATOMIC, 0);
1881 	bh_lock_sock(sk);
1882 	if ((sk->sk_state != IUCV_LISTEN) ||
1883 	    sk_acceptq_is_full(sk) ||
1884 	    !nsk) {
1885 		/* error on server socket - connection refused */
1886 		afiucv_swap_src_dest(skb);
1887 		trans_hdr->flags = AF_IUCV_FLAG_SYN | AF_IUCV_FLAG_FIN;
1888 		err = dev_queue_xmit(skb);
1889 		if (nsk)
1890 			iucv_sock_kill(nsk);
1891 		bh_unlock_sock(sk);
1892 		goto out;
1893 	}
1894 
1895 	niucv = iucv_sk(nsk);
1896 	iucv_sock_init(nsk, sk);
1897 	niucv->transport = AF_IUCV_TRANS_HIPER;
1898 	niucv->msglimit = iucv->msglimit;
1899 	if (!trans_hdr->window)
1900 		niucv->msglimit_peer = IUCV_HIPER_MSGLIM_DEFAULT;
1901 	else
1902 		niucv->msglimit_peer = trans_hdr->window;
1903 	memcpy(niucv->dst_name, trans_hdr->srcAppName, 8);
1904 	memcpy(niucv->dst_user_id, trans_hdr->srcUserID, 8);
1905 	memcpy(niucv->src_name, iucv->src_name, 8);
1906 	memcpy(niucv->src_user_id, iucv->src_user_id, 8);
1907 	nsk->sk_bound_dev_if = sk->sk_bound_dev_if;
1908 	niucv->hs_dev = iucv->hs_dev;
1909 	dev_hold(niucv->hs_dev);
1910 	afiucv_swap_src_dest(skb);
1911 	trans_hdr->flags = AF_IUCV_FLAG_SYN | AF_IUCV_FLAG_ACK;
1912 	trans_hdr->window = niucv->msglimit;
1913 	/* if receiver acks the xmit connection is established */
1914 	err = dev_queue_xmit(skb);
1915 	if (!err) {
1916 		iucv_accept_enqueue(sk, nsk);
1917 		nsk->sk_state = IUCV_CONNECTED;
1918 		sk->sk_data_ready(sk);
1919 	} else
1920 		iucv_sock_kill(nsk);
1921 	bh_unlock_sock(sk);
1922 
1923 out:
1924 	return NET_RX_SUCCESS;
1925 }
1926 
1927 /*
1928  * afiucv_hs_callback_synack() - react on received SYN-ACK
1929  */
1930 static int afiucv_hs_callback_synack(struct sock *sk, struct sk_buff *skb)
1931 {
1932 	struct iucv_sock *iucv = iucv_sk(sk);
1933 
1934 	if (!iucv || sk->sk_state != IUCV_BOUND) {
1935 		kfree_skb(skb);
1936 		return NET_RX_SUCCESS;
1937 	}
1938 
1939 	bh_lock_sock(sk);
1940 	iucv->msglimit_peer = iucv_trans_hdr(skb)->window;
1941 	sk->sk_state = IUCV_CONNECTED;
1942 	sk->sk_state_change(sk);
1943 	bh_unlock_sock(sk);
1944 	consume_skb(skb);
1945 	return NET_RX_SUCCESS;
1946 }
1947 
1948 /*
1949  * afiucv_hs_callback_synfin() - react on received SYN_FIN
1950  */
1951 static int afiucv_hs_callback_synfin(struct sock *sk, struct sk_buff *skb)
1952 {
1953 	struct iucv_sock *iucv = iucv_sk(sk);
1954 
1955 	if (!iucv || sk->sk_state != IUCV_BOUND) {
1956 		kfree_skb(skb);
1957 		return NET_RX_SUCCESS;
1958 	}
1959 
1960 	bh_lock_sock(sk);
1961 	sk->sk_state = IUCV_DISCONN;
1962 	sk->sk_state_change(sk);
1963 	bh_unlock_sock(sk);
1964 	consume_skb(skb);
1965 	return NET_RX_SUCCESS;
1966 }
1967 
1968 /*
1969  * afiucv_hs_callback_fin() - react on received FIN
1970  */
1971 static int afiucv_hs_callback_fin(struct sock *sk, struct sk_buff *skb)
1972 {
1973 	struct iucv_sock *iucv = iucv_sk(sk);
1974 
1975 	/* other end of connection closed */
1976 	if (!iucv) {
1977 		kfree_skb(skb);
1978 		return NET_RX_SUCCESS;
1979 	}
1980 
1981 	bh_lock_sock(sk);
1982 	if (sk->sk_state == IUCV_CONNECTED) {
1983 		sk->sk_state = IUCV_DISCONN;
1984 		sk->sk_state_change(sk);
1985 	}
1986 	bh_unlock_sock(sk);
1987 	consume_skb(skb);
1988 	return NET_RX_SUCCESS;
1989 }
1990 
1991 /*
1992  * afiucv_hs_callback_win() - react on received WIN
1993  */
1994 static int afiucv_hs_callback_win(struct sock *sk, struct sk_buff *skb)
1995 {
1996 	struct iucv_sock *iucv = iucv_sk(sk);
1997 
1998 	if (!iucv)
1999 		return NET_RX_SUCCESS;
2000 
2001 	if (sk->sk_state != IUCV_CONNECTED)
2002 		return NET_RX_SUCCESS;
2003 
2004 	atomic_sub(iucv_trans_hdr(skb)->window, &iucv->msg_sent);
2005 	iucv_sock_wake_msglim(sk);
2006 	return NET_RX_SUCCESS;
2007 }
2008 
2009 /*
2010  * afiucv_hs_callback_rx() - react on received data
2011  */
2012 static int afiucv_hs_callback_rx(struct sock *sk, struct sk_buff *skb)
2013 {
2014 	struct iucv_sock *iucv = iucv_sk(sk);
2015 
2016 	if (!iucv) {
2017 		kfree_skb(skb);
2018 		return NET_RX_SUCCESS;
2019 	}
2020 
2021 	if (sk->sk_state != IUCV_CONNECTED) {
2022 		kfree_skb(skb);
2023 		return NET_RX_SUCCESS;
2024 	}
2025 
2026 	if (sk->sk_shutdown & RCV_SHUTDOWN) {
2027 		kfree_skb(skb);
2028 		return NET_RX_SUCCESS;
2029 	}
2030 
2031 	/* write stuff from iucv_msg to skb cb */
2032 	skb_pull(skb, sizeof(struct af_iucv_trans_hdr));
2033 	skb_reset_transport_header(skb);
2034 	skb_reset_network_header(skb);
2035 	IUCV_SKB_CB(skb)->offset = 0;
2036 	if (sk_filter(sk, skb)) {
2037 		sk_drops_inc(sk);	/* skb rejected by filter */
2038 		kfree_skb(skb);
2039 		return NET_RX_SUCCESS;
2040 	}
2041 
2042 	spin_lock(&iucv->message_q.lock);
2043 	if (skb_queue_empty(&iucv->backlog_skb_q)) {
2044 		if (__sock_queue_rcv_skb(sk, skb))
2045 			/* handle rcv queue full */
2046 			skb_queue_tail(&iucv->backlog_skb_q, skb);
2047 	} else
2048 		skb_queue_tail(&iucv_sk(sk)->backlog_skb_q, skb);
2049 	spin_unlock(&iucv->message_q.lock);
2050 	return NET_RX_SUCCESS;
2051 }
2052 
2053 /*
2054  * afiucv_hs_rcv() - base function for arriving data through HiperSockets
2055  *                   transport
2056  *                   called from netif RX softirq
2057  */
2058 static int afiucv_hs_rcv(struct sk_buff *skb, struct net_device *dev,
2059 	struct packet_type *pt, struct net_device *orig_dev)
2060 {
2061 	struct sock *sk;
2062 	struct iucv_sock *iucv;
2063 	struct af_iucv_trans_hdr *trans_hdr;
2064 	int err = NET_RX_SUCCESS;
2065 	char nullstring[8];
2066 
2067 	if (!pskb_may_pull(skb, sizeof(*trans_hdr))) {
2068 		kfree_skb(skb);
2069 		return NET_RX_SUCCESS;
2070 	}
2071 
2072 	trans_hdr = iucv_trans_hdr(skb);
2073 	EBCASC(trans_hdr->destAppName, sizeof(trans_hdr->destAppName));
2074 	EBCASC(trans_hdr->destUserID, sizeof(trans_hdr->destUserID));
2075 	EBCASC(trans_hdr->srcAppName, sizeof(trans_hdr->srcAppName));
2076 	EBCASC(trans_hdr->srcUserID, sizeof(trans_hdr->srcUserID));
2077 	memset(nullstring, 0, sizeof(nullstring));
2078 	iucv = NULL;
2079 	sk = NULL;
2080 	read_lock(&iucv_sk_list.lock);
2081 	sk_for_each(sk, &iucv_sk_list.head) {
2082 		if (trans_hdr->flags == AF_IUCV_FLAG_SYN) {
2083 			if ((!memcmp(&iucv_sk(sk)->src_name,
2084 				     trans_hdr->destAppName, 8)) &&
2085 			    (!memcmp(&iucv_sk(sk)->src_user_id,
2086 				     trans_hdr->destUserID, 8)) &&
2087 			    (!memcmp(&iucv_sk(sk)->dst_name, nullstring, 8)) &&
2088 			    (!memcmp(&iucv_sk(sk)->dst_user_id,
2089 				     nullstring, 8))) {
2090 				iucv = iucv_sk(sk);
2091 				break;
2092 			}
2093 		} else {
2094 			if ((!memcmp(&iucv_sk(sk)->src_name,
2095 				     trans_hdr->destAppName, 8)) &&
2096 			    (!memcmp(&iucv_sk(sk)->src_user_id,
2097 				     trans_hdr->destUserID, 8)) &&
2098 			    (!memcmp(&iucv_sk(sk)->dst_name,
2099 				     trans_hdr->srcAppName, 8)) &&
2100 			    (!memcmp(&iucv_sk(sk)->dst_user_id,
2101 				     trans_hdr->srcUserID, 8))) {
2102 				iucv = iucv_sk(sk);
2103 				break;
2104 			}
2105 		}
2106 	}
2107 	if (sk)
2108 		sock_hold(sk);
2109 	read_unlock(&iucv_sk_list.lock);
2110 	if (!iucv)
2111 		sk = NULL;
2112 
2113 	/* no sock
2114 	how should we send with no sock
2115 	1) send without sock no send rc checking?
2116 	2) introduce default sock to handle this cases
2117 
2118 	 SYN -> send SYN|ACK in good case, send SYN|FIN in bad case
2119 	 data -> send FIN
2120 	 SYN|ACK, SYN|FIN, FIN -> no action? */
2121 
2122 	switch (trans_hdr->flags) {
2123 	case AF_IUCV_FLAG_SYN:
2124 		/* connect request */
2125 		err = afiucv_hs_callback_syn(sk, skb);
2126 		break;
2127 	case (AF_IUCV_FLAG_SYN | AF_IUCV_FLAG_ACK):
2128 		/* connect request confirmed */
2129 		err = afiucv_hs_callback_synack(sk, skb);
2130 		break;
2131 	case (AF_IUCV_FLAG_SYN | AF_IUCV_FLAG_FIN):
2132 		/* connect request refused */
2133 		err = afiucv_hs_callback_synfin(sk, skb);
2134 		break;
2135 	case (AF_IUCV_FLAG_FIN):
2136 		/* close request */
2137 		err = afiucv_hs_callback_fin(sk, skb);
2138 		break;
2139 	case (AF_IUCV_FLAG_WIN):
2140 		err = afiucv_hs_callback_win(sk, skb);
2141 		if (skb->len == sizeof(struct af_iucv_trans_hdr)) {
2142 			consume_skb(skb);
2143 			break;
2144 		}
2145 		fallthrough;	/* and receive non-zero length data */
2146 	case (AF_IUCV_FLAG_SHT):
2147 		/* shutdown request */
2148 		fallthrough;	/* and receive zero length data */
2149 	case 0:
2150 		/* plain data frame */
2151 		IUCV_SKB_CB(skb)->class = trans_hdr->iucv_hdr.class;
2152 		err = afiucv_hs_callback_rx(sk, skb);
2153 		break;
2154 	default:
2155 		kfree_skb(skb);
2156 	}
2157 
2158 	if (sk)
2159 		sock_put(sk);
2160 	return err;
2161 }
2162 
2163 /*
2164  * afiucv_hs_callback_txnotify() - handle send notifications from HiperSockets
2165  *                                 transport
2166  */
2167 static void afiucv_hs_callback_txnotify(struct sock *sk, enum iucv_tx_notify n)
2168 {
2169 	struct iucv_sock *iucv = iucv_sk(sk);
2170 
2171 	if (sock_flag(sk, SOCK_ZAPPED))
2172 		return;
2173 
2174 	switch (n) {
2175 	case TX_NOTIFY_OK:
2176 		atomic_dec(&iucv->skbs_in_xmit);
2177 		iucv_sock_wake_msglim(sk);
2178 		break;
2179 	case TX_NOTIFY_PENDING:
2180 		atomic_inc(&iucv->pendings);
2181 		break;
2182 	case TX_NOTIFY_DELAYED_OK:
2183 		atomic_dec(&iucv->skbs_in_xmit);
2184 		if (atomic_dec_return(&iucv->pendings) <= 0)
2185 			iucv_sock_wake_msglim(sk);
2186 		break;
2187 	default:
2188 		atomic_dec(&iucv->skbs_in_xmit);
2189 		if (sk->sk_state == IUCV_CONNECTED) {
2190 			sk->sk_state = IUCV_DISCONN;
2191 			sk->sk_state_change(sk);
2192 		}
2193 	}
2194 
2195 	if (sk->sk_state == IUCV_CLOSING) {
2196 		if (atomic_read(&iucv->skbs_in_xmit) == 0) {
2197 			sk->sk_state = IUCV_CLOSED;
2198 			sk->sk_state_change(sk);
2199 		}
2200 	}
2201 }
2202 
2203 /*
2204  * afiucv_netdev_event: handle netdev notifier chain events
2205  */
2206 static int afiucv_netdev_event(struct notifier_block *this,
2207 			       unsigned long event, void *ptr)
2208 {
2209 	struct net_device *event_dev = netdev_notifier_info_to_dev(ptr);
2210 	struct sock *sk;
2211 	struct iucv_sock *iucv;
2212 
2213 	switch (event) {
2214 	case NETDEV_REBOOT:
2215 	case NETDEV_GOING_DOWN:
2216 		sk_for_each(sk, &iucv_sk_list.head) {
2217 			iucv = iucv_sk(sk);
2218 			if ((iucv->hs_dev == event_dev) &&
2219 			    (sk->sk_state == IUCV_CONNECTED)) {
2220 				if (event == NETDEV_GOING_DOWN)
2221 					iucv_send_ctrl(sk, AF_IUCV_FLAG_FIN);
2222 				sk->sk_state = IUCV_DISCONN;
2223 				sk->sk_state_change(sk);
2224 			}
2225 		}
2226 		break;
2227 	case NETDEV_DOWN:
2228 	case NETDEV_UNREGISTER:
2229 	default:
2230 		break;
2231 	}
2232 	return NOTIFY_DONE;
2233 }
2234 
2235 static struct notifier_block afiucv_netdev_notifier = {
2236 	.notifier_call = afiucv_netdev_event,
2237 };
2238 
2239 static const struct proto_ops iucv_sock_ops = {
2240 	.family		= PF_IUCV,
2241 	.owner		= THIS_MODULE,
2242 	.release	= iucv_sock_release,
2243 	.bind		= iucv_sock_bind,
2244 	.connect	= iucv_sock_connect,
2245 	.listen		= iucv_sock_listen,
2246 	.accept		= iucv_sock_accept,
2247 	.getname	= iucv_sock_getname,
2248 	.sendmsg	= iucv_sock_sendmsg,
2249 	.recvmsg	= iucv_sock_recvmsg,
2250 	.poll		= iucv_sock_poll,
2251 	.ioctl		= sock_no_ioctl,
2252 	.mmap		= sock_no_mmap,
2253 	.socketpair	= sock_no_socketpair,
2254 	.shutdown	= iucv_sock_shutdown,
2255 	.setsockopt	= iucv_sock_setsockopt,
2256 	.getsockopt_iter = iucv_sock_getsockopt,
2257 };
2258 
2259 static int iucv_sock_create(struct net *net, struct socket *sock, int protocol,
2260 			    int kern)
2261 {
2262 	struct sock *sk;
2263 
2264 	if (protocol && protocol != PF_IUCV)
2265 		return -EPROTONOSUPPORT;
2266 
2267 	sock->state = SS_UNCONNECTED;
2268 
2269 	switch (sock->type) {
2270 	case SOCK_STREAM:
2271 	case SOCK_SEQPACKET:
2272 		/* currently, proto ops can handle both sk types */
2273 		sock->ops = &iucv_sock_ops;
2274 		break;
2275 	default:
2276 		return -ESOCKTNOSUPPORT;
2277 	}
2278 
2279 	sk = iucv_sock_alloc(sock, protocol, GFP_KERNEL, kern);
2280 	if (!sk)
2281 		return -ENOMEM;
2282 
2283 	iucv_sock_init(sk, NULL);
2284 
2285 	return 0;
2286 }
2287 
2288 static const struct net_proto_family iucv_sock_family_ops = {
2289 	.family	= AF_IUCV,
2290 	.owner	= THIS_MODULE,
2291 	.create	= iucv_sock_create,
2292 };
2293 
2294 static struct packet_type iucv_packet_type = {
2295 	.type = cpu_to_be16(ETH_P_AF_IUCV),
2296 	.func = afiucv_hs_rcv,
2297 };
2298 
2299 static int __init afiucv_init(void)
2300 {
2301 	int err;
2302 
2303 	if (machine_is_vm() && IS_ENABLED(CONFIG_IUCV)) {
2304 		cpcmd("QUERY USERID", iucv_userid, sizeof(iucv_userid), &err);
2305 		if (unlikely(err)) {
2306 			WARN_ON(err);
2307 			err = -EPROTONOSUPPORT;
2308 			goto out;
2309 		}
2310 
2311 		pr_iucv = &iucv_if;
2312 	} else {
2313 		memset(&iucv_userid, 0, sizeof(iucv_userid));
2314 		pr_iucv = NULL;
2315 	}
2316 
2317 	err = proto_register(&iucv_proto, 0);
2318 	if (err)
2319 		goto out;
2320 	err = sock_register(&iucv_sock_family_ops);
2321 	if (err)
2322 		goto out_proto;
2323 
2324 	if (pr_iucv) {
2325 		err = pr_iucv->iucv_register(&af_iucv_handler, 0);
2326 		if (err)
2327 			goto out_sock;
2328 	}
2329 
2330 	err = register_netdevice_notifier(&afiucv_netdev_notifier);
2331 	if (err)
2332 		goto out_notifier;
2333 
2334 	dev_add_pack(&iucv_packet_type);
2335 	return 0;
2336 
2337 out_notifier:
2338 	if (pr_iucv)
2339 		pr_iucv->iucv_unregister(&af_iucv_handler, 0);
2340 out_sock:
2341 	sock_unregister(PF_IUCV);
2342 out_proto:
2343 	proto_unregister(&iucv_proto);
2344 out:
2345 	return err;
2346 }
2347 
2348 static void __exit afiucv_exit(void)
2349 {
2350 	if (pr_iucv)
2351 		pr_iucv->iucv_unregister(&af_iucv_handler, 0);
2352 
2353 	unregister_netdevice_notifier(&afiucv_netdev_notifier);
2354 	dev_remove_pack(&iucv_packet_type);
2355 	sock_unregister(PF_IUCV);
2356 	proto_unregister(&iucv_proto);
2357 }
2358 
2359 module_init(afiucv_init);
2360 module_exit(afiucv_exit);
2361 
2362 MODULE_AUTHOR("Jennifer Hunt <jenhunt@us.ibm.com>");
2363 MODULE_DESCRIPTION("IUCV Sockets ver " VERSION);
2364 MODULE_VERSION(VERSION);
2365 MODULE_LICENSE("GPL");
2366 MODULE_ALIAS_NETPROTO(PF_IUCV);
2367