xref: /linux/net/iucv/af_iucv.c (revision 3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d)
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 	memcpy(phs_hdr->destUserID, iucv->dst_user_id, 8);
214 	memcpy(phs_hdr->destAppName, iucv->dst_name, 8);
215 	memcpy(phs_hdr->srcUserID, iucv->src_user_id, 8);
216 	memcpy(phs_hdr->srcAppName, iucv->src_name, 8);
217 	ASCEBC(phs_hdr->destUserID, sizeof(phs_hdr->destUserID));
218 	ASCEBC(phs_hdr->destAppName, sizeof(phs_hdr->destAppName));
219 	ASCEBC(phs_hdr->srcUserID, sizeof(phs_hdr->srcUserID));
220 	ASCEBC(phs_hdr->srcAppName, sizeof(phs_hdr->srcAppName));
221 	if (imsg)
222 		memcpy(&phs_hdr->iucv_hdr, imsg, sizeof(struct iucv_message));
223 
224 	skb->dev = iucv->hs_dev;
225 	if (!skb->dev) {
226 		err = -ENODEV;
227 		goto err_free;
228 	}
229 
230 	dev_hard_header(skb, skb->dev, ETH_P_AF_IUCV, NULL, NULL, skb->len);
231 
232 	if (!(skb->dev->flags & IFF_UP) || !netif_carrier_ok(skb->dev)) {
233 		err = -ENETDOWN;
234 		goto err_free;
235 	}
236 	if (skb->len > skb->dev->mtu) {
237 		if (sock->sk_type == SOCK_SEQPACKET) {
238 			err = -EMSGSIZE;
239 			goto err_free;
240 		}
241 		err = pskb_trim(skb, skb->dev->mtu);
242 		if (err)
243 			goto err_free;
244 	}
245 	skb->protocol = cpu_to_be16(ETH_P_AF_IUCV);
246 
247 	/* Claim the receive credit here, not while building the header: every
248 	 * way this frame can be dropped has now been ruled out, so the window
249 	 * is zeroed only for as long as the transmit itself takes.
250 	 */
251 	if (flags == AF_IUCV_FLAG_WIN || !flags) {
252 		confirm_recv = atomic_xchg(&iucv->msg_recv, 0);
253 		phs_hdr->window = confirm_recv;
254 		if (confirm_recv)
255 			phs_hdr->flags = phs_hdr->flags | AF_IUCV_FLAG_WIN;
256 	}
257 
258 	atomic_inc(&iucv->skbs_in_xmit);
259 	err = dev_queue_xmit(skb);
260 	if (net_xmit_eval(err)) {
261 		atomic_dec(&iucv->skbs_in_xmit);
262 		atomic_add(confirm_recv, &iucv->msg_recv);
263 	}
264 	return net_xmit_eval(err);
265 
266 err_free:
267 	kfree_skb(skb);
268 	return err;
269 }
270 
271 static struct sock *__iucv_get_sock_by_name(char *nm)
272 {
273 	struct sock *sk;
274 
275 	sk_for_each(sk, &iucv_sk_list.head)
276 		if (!memcmp(&iucv_sk(sk)->src_name, nm, 8))
277 			return sk;
278 
279 	return NULL;
280 }
281 
282 static void iucv_sock_destruct(struct sock *sk)
283 {
284 	skb_queue_purge(&sk->sk_receive_queue);
285 	skb_queue_purge(&sk->sk_error_queue);
286 
287 	if (!sock_flag(sk, SOCK_DEAD)) {
288 		pr_err("Attempt to release alive iucv socket %p\n", sk);
289 		return;
290 	}
291 
292 	WARN_ON(atomic_read(&sk->sk_rmem_alloc));
293 	WARN_ON(refcount_read(&sk->sk_wmem_alloc));
294 	WARN_ON(sk->sk_wmem_queued);
295 	WARN_ON(sk->sk_forward_alloc);
296 }
297 
298 /* Cleanup Listen */
299 static void iucv_sock_cleanup_listen(struct sock *parent)
300 {
301 	struct sock *sk;
302 
303 	/* Close non-accepted connections */
304 	while ((sk = iucv_accept_dequeue(parent, NULL))) {
305 		iucv_sock_close(sk);
306 		iucv_sock_kill(sk);
307 	}
308 
309 	parent->sk_state = IUCV_CLOSED;
310 }
311 
312 static void iucv_sock_link(struct iucv_sock_list *l, struct sock *sk)
313 {
314 	write_lock_bh(&l->lock);
315 	sk_add_node(sk, &l->head);
316 	write_unlock_bh(&l->lock);
317 }
318 
319 static void iucv_sock_unlink(struct iucv_sock_list *l, struct sock *sk)
320 {
321 	write_lock_bh(&l->lock);
322 	sk_del_node_init(sk);
323 	write_unlock_bh(&l->lock);
324 }
325 
326 /* Kill socket (only if zapped and orphaned) */
327 static void iucv_sock_kill(struct sock *sk)
328 {
329 	if (!sock_flag(sk, SOCK_ZAPPED) || sk->sk_socket)
330 		return;
331 
332 	iucv_sock_unlink(&iucv_sk_list, sk);
333 	sock_set_flag(sk, SOCK_DEAD);
334 	sock_put(sk);
335 }
336 
337 /* Terminate an IUCV path */
338 static void iucv_sever_path(struct sock *sk, int with_user_data)
339 {
340 	unsigned char user_data[16];
341 	struct iucv_sock *iucv = iucv_sk(sk);
342 	struct iucv_path *path = iucv->path;
343 	struct sock_msg_q *p, *n;
344 
345 	/* Whoever resets the path pointer, must sever and free it. */
346 	if (xchg(&iucv->path, NULL)) {
347 		if (with_user_data) {
348 			low_nmcpy(user_data, iucv->src_name);
349 			high_nmcpy(user_data, iucv->dst_name);
350 			ASCEBC(user_data, sizeof(user_data));
351 			pr_iucv->path_sever(path, user_data);
352 		} else
353 			pr_iucv->path_sever(path, NULL);
354 		iucv_path_free(path);
355 
356 		/*
357 		 * Message notifications queued on message_q still reference
358 		 * the now freed path; drop them, otherwise a later recvmsg()
359 		 * would pass the freed iucv_path to message_receive() via
360 		 * iucv_process_message_q().
361 		 */
362 		spin_lock_bh(&iucv->message_q.lock);
363 		list_for_each_entry_safe(p, n, &iucv->message_q.list, list) {
364 			list_del(&p->list);
365 			kfree(p);
366 		}
367 		spin_unlock_bh(&iucv->message_q.lock);
368 	}
369 }
370 
371 /* Send controlling flags through an IUCV socket for HIPER transport */
372 static int iucv_send_ctrl(struct sock *sk, u8 flags)
373 {
374 	struct iucv_sock *iucv = iucv_sk(sk);
375 	int err = 0;
376 	int blen;
377 	struct sk_buff *skb;
378 	u8 shutdown = 0;
379 
380 	blen = sizeof(struct af_iucv_trans_hdr) +
381 	       LL_RESERVED_SPACE(iucv->hs_dev);
382 	if (sk->sk_shutdown & SEND_SHUTDOWN) {
383 		/* controlling flags should be sent anyway */
384 		shutdown = sk->sk_shutdown;
385 		sk->sk_shutdown &= RCV_SHUTDOWN;
386 	}
387 	skb = sock_alloc_send_skb(sk, blen, 1, &err);
388 	if (skb) {
389 		skb_reserve(skb, blen);
390 		err = afiucv_hs_send(NULL, sk, skb, flags);
391 	}
392 	if (shutdown)
393 		sk->sk_shutdown = shutdown;
394 	return err;
395 }
396 
397 /* Close an IUCV socket */
398 static void iucv_sock_close(struct sock *sk)
399 {
400 	struct iucv_sock *iucv = iucv_sk(sk);
401 	unsigned long timeo;
402 	int err = 0;
403 
404 	lock_sock(sk);
405 
406 	switch (sk->sk_state) {
407 	case IUCV_LISTEN:
408 		iucv_sock_cleanup_listen(sk);
409 		break;
410 
411 	case IUCV_CONNECTED:
412 		if (iucv->transport == AF_IUCV_TRANS_HIPER) {
413 			err = iucv_send_ctrl(sk, AF_IUCV_FLAG_FIN);
414 			sk->sk_state = IUCV_DISCONN;
415 			sk->sk_state_change(sk);
416 		}
417 		fallthrough;
418 
419 	case IUCV_DISCONN:
420 		sk->sk_state = IUCV_CLOSING;
421 		sk->sk_state_change(sk);
422 
423 		if (!err && atomic_read(&iucv->skbs_in_xmit) > 0) {
424 			if (sock_flag(sk, SOCK_LINGER) && sk->sk_lingertime)
425 				timeo = sk->sk_lingertime;
426 			else
427 				timeo = IUCV_DISCONN_TIMEOUT;
428 			iucv_sock_wait(sk,
429 					iucv_sock_in_state(sk, IUCV_CLOSED, 0),
430 					timeo);
431 		}
432 		fallthrough;
433 
434 	case IUCV_CLOSING:
435 		sk->sk_state = IUCV_CLOSED;
436 		sk->sk_state_change(sk);
437 
438 		sk->sk_err = ECONNRESET;
439 		sk->sk_state_change(sk);
440 
441 		skb_queue_purge(&iucv->send_skb_q);
442 		skb_queue_purge(&iucv->backlog_skb_q);
443 		fallthrough;
444 
445 	default:
446 		iucv_sever_path(sk, 1);
447 	}
448 
449 	if (iucv->hs_dev) {
450 		dev_put(iucv->hs_dev);
451 		iucv->hs_dev = NULL;
452 		sk->sk_bound_dev_if = 0;
453 	}
454 
455 	/* mark socket for deletion by iucv_sock_kill() */
456 	sock_set_flag(sk, SOCK_ZAPPED);
457 
458 	release_sock(sk);
459 }
460 
461 static void iucv_sock_init(struct sock *sk, struct sock *parent)
462 {
463 	if (parent) {
464 		sk->sk_type = parent->sk_type;
465 		security_sk_clone(parent, sk);
466 	}
467 }
468 
469 static struct sock *iucv_sock_alloc(struct socket *sock, int proto, gfp_t prio, int kern)
470 {
471 	struct sock *sk;
472 	struct iucv_sock *iucv;
473 
474 	sk = sk_alloc(&init_net, PF_IUCV, prio, &iucv_proto, kern);
475 	if (!sk)
476 		return NULL;
477 	iucv = iucv_sk(sk);
478 
479 	sock_init_data(sock, sk);
480 	INIT_LIST_HEAD(&iucv->accept_q);
481 	spin_lock_init(&iucv->accept_q_lock);
482 	skb_queue_head_init(&iucv->send_skb_q);
483 	INIT_LIST_HEAD(&iucv->message_q.list);
484 	spin_lock_init(&iucv->message_q.lock);
485 	skb_queue_head_init(&iucv->backlog_skb_q);
486 	iucv->send_tag = 0;
487 	atomic_set(&iucv->pendings, 0);
488 	iucv->flags = 0;
489 	iucv->msglimit = 0;
490 	atomic_set(&iucv->skbs_in_xmit, 0);
491 	atomic_set(&iucv->msg_sent, 0);
492 	atomic_set(&iucv->msg_recv, 0);
493 	iucv->path = NULL;
494 	iucv->sk_txnotify = afiucv_hs_callback_txnotify;
495 	memset(&iucv->init, 0, sizeof(iucv->init));
496 	if (pr_iucv)
497 		iucv->transport = AF_IUCV_TRANS_IUCV;
498 	else
499 		iucv->transport = AF_IUCV_TRANS_HIPER;
500 
501 	sk->sk_destruct = iucv_sock_destruct;
502 	sk->sk_sndtimeo = IUCV_CONN_TIMEOUT;
503 
504 	sock_reset_flag(sk, SOCK_ZAPPED);
505 
506 	sk->sk_protocol = proto;
507 	sk->sk_state	= IUCV_OPEN;
508 
509 	iucv_sock_link(&iucv_sk_list, sk);
510 	return sk;
511 }
512 
513 static void iucv_accept_enqueue(struct sock *parent, struct sock *sk)
514 {
515 	unsigned long flags;
516 	struct iucv_sock *par = iucv_sk(parent);
517 
518 	sock_hold(sk);
519 	spin_lock_irqsave(&par->accept_q_lock, flags);
520 	list_add_tail(&iucv_sk(sk)->accept_q, &par->accept_q);
521 	spin_unlock_irqrestore(&par->accept_q_lock, flags);
522 	iucv_sk(sk)->parent = parent;
523 	sk_acceptq_added(parent);
524 }
525 
526 static void iucv_accept_unlink(struct sock *sk)
527 {
528 	unsigned long flags;
529 	struct iucv_sock *par = iucv_sk(iucv_sk(sk)->parent);
530 
531 	spin_lock_irqsave(&par->accept_q_lock, flags);
532 	list_del_init(&iucv_sk(sk)->accept_q);
533 	spin_unlock_irqrestore(&par->accept_q_lock, flags);
534 	sk_acceptq_removed(iucv_sk(sk)->parent);
535 	iucv_sk(sk)->parent = NULL;
536 	sock_put(sk);
537 }
538 
539 static struct sock *iucv_accept_dequeue(struct sock *parent,
540 					struct socket *newsock)
541 {
542 	struct iucv_sock *isk, *n;
543 	struct sock *sk;
544 
545 	list_for_each_entry_safe(isk, n, &iucv_sk(parent)->accept_q, accept_q) {
546 		sk = (struct sock *) isk;
547 		lock_sock(sk);
548 
549 		if (sk->sk_state == IUCV_CLOSED) {
550 			iucv_accept_unlink(sk);
551 			release_sock(sk);
552 			continue;
553 		}
554 
555 		if (sk->sk_state == IUCV_CONNECTED ||
556 		    sk->sk_state == IUCV_DISCONN ||
557 		    !newsock) {
558 			iucv_accept_unlink(sk);
559 			if (newsock)
560 				sock_graft(sk, newsock);
561 
562 			release_sock(sk);
563 			return sk;
564 		}
565 
566 		release_sock(sk);
567 	}
568 	return NULL;
569 }
570 
571 static void __iucv_auto_name(struct iucv_sock *iucv)
572 {
573 	char name[12];
574 
575 	scnprintf(name, sizeof(name),
576 		  "%08x", atomic_inc_return(&iucv_sk_list.autobind_name));
577 	while (__iucv_get_sock_by_name(name)) {
578 		scnprintf(name, sizeof(name), "%08x",
579 			  atomic_inc_return(&iucv_sk_list.autobind_name));
580 	}
581 	memcpy(iucv->src_name, name, 8);
582 }
583 
584 /* Bind an unbound socket */
585 static int iucv_sock_bind(struct socket *sock, struct sockaddr_unsized *addr,
586 			  int addr_len)
587 {
588 	DECLARE_SOCKADDR(struct sockaddr_iucv *, sa, addr);
589 	char uid[sizeof(sa->siucv_user_id)];
590 	struct sock *sk = sock->sk;
591 	struct iucv_sock *iucv;
592 	int err = 0;
593 	struct net_device *dev;
594 
595 	/* Verify the input sockaddr */
596 	if (addr_len < sizeof(struct sockaddr_iucv) ||
597 	    addr->sa_family != AF_IUCV)
598 		return -EINVAL;
599 
600 	lock_sock(sk);
601 	if (sk->sk_state != IUCV_OPEN) {
602 		err = -EBADFD;
603 		goto done;
604 	}
605 
606 	write_lock_bh(&iucv_sk_list.lock);
607 
608 	iucv = iucv_sk(sk);
609 	if (__iucv_get_sock_by_name(sa->siucv_name)) {
610 		err = -EADDRINUSE;
611 		goto done_unlock;
612 	}
613 	if (iucv->path)
614 		goto done_unlock;
615 
616 	/* Bind the socket */
617 	if (pr_iucv)
618 		if (!memcmp(sa->siucv_user_id, iucv_userid, 8))
619 			goto vm_bind; /* VM IUCV transport */
620 
621 	/* try hiper transport */
622 	memcpy(uid, sa->siucv_user_id, sizeof(uid));
623 	ASCEBC(uid, 8);
624 	rcu_read_lock();
625 	for_each_netdev_rcu(&init_net, dev) {
626 		if (!memcmp(dev->perm_addr, uid, 8)) {
627 			memcpy(iucv->src_user_id, sa->siucv_user_id, 8);
628 			/* Check for uninitialized siucv_name */
629 			if (strncmp(sa->siucv_name, "        ", 8) == 0)
630 				__iucv_auto_name(iucv);
631 			else
632 				memcpy(iucv->src_name, sa->siucv_name, 8);
633 			sk->sk_bound_dev_if = dev->ifindex;
634 			iucv->hs_dev = dev;
635 			dev_hold(dev);
636 			sk->sk_state = IUCV_BOUND;
637 			iucv->transport = AF_IUCV_TRANS_HIPER;
638 			if (!iucv->msglimit)
639 				iucv->msglimit = IUCV_HIPER_MSGLIM_DEFAULT;
640 			rcu_read_unlock();
641 			goto done_unlock;
642 		}
643 	}
644 	rcu_read_unlock();
645 vm_bind:
646 	if (pr_iucv) {
647 		/* use local userid for backward compat */
648 		memcpy(iucv->src_name, sa->siucv_name, 8);
649 		memcpy(iucv->src_user_id, iucv_userid, 8);
650 		sk->sk_state = IUCV_BOUND;
651 		iucv->transport = AF_IUCV_TRANS_IUCV;
652 		sk->sk_allocation |= GFP_DMA;
653 		if (!iucv->msglimit)
654 			iucv->msglimit = IUCV_QUEUELEN_DEFAULT;
655 		goto done_unlock;
656 	}
657 	/* found no dev to bind */
658 	err = -ENODEV;
659 done_unlock:
660 	/* Release the socket list lock */
661 	write_unlock_bh(&iucv_sk_list.lock);
662 done:
663 	release_sock(sk);
664 	return err;
665 }
666 
667 /* Automatically bind an unbound socket */
668 static int iucv_sock_autobind(struct sock *sk)
669 {
670 	struct iucv_sock *iucv = iucv_sk(sk);
671 	int err = 0;
672 
673 	if (unlikely(!pr_iucv))
674 		return -EPROTO;
675 
676 	memcpy(iucv->src_user_id, iucv_userid, 8);
677 	iucv->transport = AF_IUCV_TRANS_IUCV;
678 	sk->sk_allocation |= GFP_DMA;
679 
680 	write_lock_bh(&iucv_sk_list.lock);
681 	__iucv_auto_name(iucv);
682 	write_unlock_bh(&iucv_sk_list.lock);
683 
684 	if (!iucv->msglimit)
685 		iucv->msglimit = IUCV_QUEUELEN_DEFAULT;
686 
687 	return err;
688 }
689 
690 static int afiucv_path_connect(struct socket *sock, struct sockaddr_unsized *addr)
691 {
692 	DECLARE_SOCKADDR(struct sockaddr_iucv *, sa, addr);
693 	struct sock *sk = sock->sk;
694 	struct iucv_sock *iucv = iucv_sk(sk);
695 	unsigned char user_data[16];
696 	int err;
697 
698 	high_nmcpy(user_data, sa->siucv_name);
699 	low_nmcpy(user_data, iucv->src_name);
700 	ASCEBC(user_data, sizeof(user_data));
701 
702 	/* Create path. */
703 	iucv->path = iucv_path_alloc(iucv->msglimit,
704 				     IUCV_IPRMDATA, GFP_KERNEL);
705 	if (!iucv->path) {
706 		err = -ENOMEM;
707 		goto done;
708 	}
709 	err = pr_iucv->path_connect(iucv->path, &af_iucv_handler,
710 				    sa->siucv_user_id, NULL, user_data,
711 				    sk);
712 	if (err) {
713 		iucv_path_free(iucv->path);
714 		iucv->path = NULL;
715 		switch (err) {
716 		case 0x0b:	/* Target communicator is not logged on */
717 			err = -ENETUNREACH;
718 			break;
719 		case 0x0d:	/* Max connections for this guest exceeded */
720 		case 0x0e:	/* Max connections for target guest exceeded */
721 			err = -EAGAIN;
722 			break;
723 		case 0x0f:	/* Missing IUCV authorization */
724 			err = -EACCES;
725 			break;
726 		default:
727 			err = -ECONNREFUSED;
728 			break;
729 		}
730 	}
731 done:
732 	return err;
733 }
734 
735 /* Connect an unconnected socket */
736 static int iucv_sock_connect(struct socket *sock, struct sockaddr_unsized *addr,
737 			     int alen, int flags)
738 {
739 	DECLARE_SOCKADDR(struct sockaddr_iucv *, sa, addr);
740 	struct sock *sk = sock->sk;
741 	struct iucv_sock *iucv = iucv_sk(sk);
742 	int err;
743 
744 	if (alen < sizeof(struct sockaddr_iucv) || addr->sa_family != AF_IUCV)
745 		return -EINVAL;
746 
747 	if (sk->sk_state != IUCV_OPEN && sk->sk_state != IUCV_BOUND)
748 		return -EBADFD;
749 
750 	if (sk->sk_state == IUCV_OPEN &&
751 	    iucv->transport == AF_IUCV_TRANS_HIPER)
752 		return -EBADFD; /* explicit bind required */
753 
754 	if (sk->sk_type != SOCK_STREAM && sk->sk_type != SOCK_SEQPACKET)
755 		return -EINVAL;
756 
757 	if (sk->sk_state == IUCV_OPEN) {
758 		err = iucv_sock_autobind(sk);
759 		if (unlikely(err))
760 			return err;
761 	}
762 
763 	lock_sock(sk);
764 
765 	/* Set the destination information */
766 	memcpy(iucv->dst_user_id, sa->siucv_user_id, 8);
767 	memcpy(iucv->dst_name, sa->siucv_name, 8);
768 
769 	if (iucv->transport == AF_IUCV_TRANS_HIPER)
770 		err = iucv_send_ctrl(sock->sk, AF_IUCV_FLAG_SYN);
771 	else
772 		err = afiucv_path_connect(sock, addr);
773 	if (err)
774 		goto done;
775 
776 	if (sk->sk_state != IUCV_CONNECTED)
777 		err = iucv_sock_wait(sk, iucv_sock_in_state(sk, IUCV_CONNECTED,
778 							    IUCV_DISCONN),
779 				     sock_sndtimeo(sk, flags & O_NONBLOCK));
780 
781 	if (sk->sk_state == IUCV_DISCONN || sk->sk_state == IUCV_CLOSED)
782 		err = -ECONNREFUSED;
783 
784 	if (err && iucv->transport == AF_IUCV_TRANS_IUCV)
785 		iucv_sever_path(sk, 0);
786 
787 done:
788 	release_sock(sk);
789 	return err;
790 }
791 
792 /* Move a socket into listening state. */
793 static int iucv_sock_listen(struct socket *sock, int backlog)
794 {
795 	struct sock *sk = sock->sk;
796 	int err;
797 
798 	lock_sock(sk);
799 
800 	err = -EINVAL;
801 	if (sk->sk_state != IUCV_BOUND)
802 		goto done;
803 
804 	if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
805 		goto done;
806 
807 	sk->sk_max_ack_backlog = backlog;
808 	sk->sk_ack_backlog = 0;
809 	sk->sk_state = IUCV_LISTEN;
810 	err = 0;
811 
812 done:
813 	release_sock(sk);
814 	return err;
815 }
816 
817 /* Accept a pending connection */
818 static int iucv_sock_accept(struct socket *sock, struct socket *newsock,
819 			    struct proto_accept_arg *arg)
820 {
821 	DECLARE_WAITQUEUE(wait, current);
822 	struct sock *sk = sock->sk, *nsk;
823 	long timeo;
824 	int err = 0;
825 
826 	lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
827 
828 	if (sk->sk_state != IUCV_LISTEN) {
829 		err = -EBADFD;
830 		goto done;
831 	}
832 
833 	timeo = sock_rcvtimeo(sk, arg->flags & O_NONBLOCK);
834 
835 	/* Wait for an incoming connection */
836 	add_wait_queue_exclusive(sk_sleep(sk), &wait);
837 	while (!(nsk = iucv_accept_dequeue(sk, newsock))) {
838 		set_current_state(TASK_INTERRUPTIBLE);
839 		if (!timeo) {
840 			err = -EAGAIN;
841 			break;
842 		}
843 
844 		release_sock(sk);
845 		timeo = schedule_timeout(timeo);
846 		lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
847 
848 		if (sk->sk_state != IUCV_LISTEN) {
849 			err = -EBADFD;
850 			break;
851 		}
852 
853 		if (signal_pending(current)) {
854 			err = sock_intr_errno(timeo);
855 			break;
856 		}
857 	}
858 
859 	set_current_state(TASK_RUNNING);
860 	remove_wait_queue(sk_sleep(sk), &wait);
861 
862 	if (err)
863 		goto done;
864 
865 	newsock->state = SS_CONNECTED;
866 
867 done:
868 	release_sock(sk);
869 	return err;
870 }
871 
872 static int iucv_sock_getname(struct socket *sock, struct sockaddr *addr,
873 			     int peer)
874 {
875 	DECLARE_SOCKADDR(struct sockaddr_iucv *, siucv, addr);
876 	struct sock *sk = sock->sk;
877 	struct iucv_sock *iucv = iucv_sk(sk);
878 
879 	addr->sa_family = AF_IUCV;
880 
881 	if (peer) {
882 		memcpy(siucv->siucv_user_id, iucv->dst_user_id, 8);
883 		memcpy(siucv->siucv_name, iucv->dst_name, 8);
884 	} else {
885 		memcpy(siucv->siucv_user_id, iucv->src_user_id, 8);
886 		memcpy(siucv->siucv_name, iucv->src_name, 8);
887 	}
888 	memset(&siucv->siucv_port, 0, sizeof(siucv->siucv_port));
889 	memset(&siucv->siucv_addr, 0, sizeof(siucv->siucv_addr));
890 	memset(&siucv->siucv_nodeid, 0, sizeof(siucv->siucv_nodeid));
891 
892 	return sizeof(struct sockaddr_iucv);
893 }
894 
895 /**
896  * iucv_send_iprm() - Send socket data in parameter list of an iucv message.
897  * @path:	IUCV path
898  * @msg:	Pointer to a struct iucv_message
899  * @skb:	The socket data to send, skb->len MUST BE <= 7
900  *
901  * Send the socket data in the parameter list in the iucv message
902  * (IUCV_IPRMDATA). The socket data is stored at index 0 to 6 in the parameter
903  * list and the socket data len at index 7 (last byte).
904  * See also iucv_msg_length().
905  *
906  * Returns: the return code from the iucv_message_send() call.
907  */
908 static int iucv_send_iprm(struct iucv_path *path, struct iucv_message *msg,
909 			  struct sk_buff *skb)
910 {
911 	u8 prmdata[8];
912 
913 	memcpy(prmdata, (void *) skb->data, skb->len);
914 	prmdata[7] = 0xff - (u8) skb->len;
915 	return pr_iucv->message_send(path, msg, IUCV_IPRMDATA, 0,
916 				 (void *) prmdata, 8);
917 }
918 
919 static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg,
920 			     size_t len)
921 {
922 	struct sock *sk = sock->sk;
923 	struct iucv_sock *iucv = iucv_sk(sk);
924 	size_t headroom = 0;
925 	size_t linear;
926 	struct sk_buff *skb;
927 	struct iucv_message txmsg = {0};
928 	struct cmsghdr *cmsg;
929 	int cmsg_done;
930 	long timeo;
931 	char user_id[9];
932 	char appl_id[9];
933 	int err;
934 	int noblock = msg->msg_flags & MSG_DONTWAIT;
935 
936 	err = sock_error(sk);
937 	if (err)
938 		return err;
939 
940 	if (msg->msg_flags & MSG_OOB)
941 		return -EOPNOTSUPP;
942 
943 	/* SOCK_SEQPACKET: we do not support segmented records */
944 	if (sk->sk_type == SOCK_SEQPACKET && !(msg->msg_flags & MSG_EOR))
945 		return -EOPNOTSUPP;
946 
947 	lock_sock(sk);
948 
949 	if (sk->sk_shutdown & SEND_SHUTDOWN) {
950 		err = -EPIPE;
951 		goto out;
952 	}
953 
954 	/* Return if the socket is not in connected state */
955 	if (sk->sk_state != IUCV_CONNECTED) {
956 		err = -ENOTCONN;
957 		goto out;
958 	}
959 
960 	/* initialize defaults */
961 	cmsg_done   = 0;	/* check for duplicate headers */
962 
963 	/* iterate over control messages */
964 	for_each_cmsghdr(cmsg, msg) {
965 		if (!CMSG_OK(msg, cmsg)) {
966 			err = -EINVAL;
967 			goto out;
968 		}
969 
970 		if (cmsg->cmsg_level != SOL_IUCV)
971 			continue;
972 
973 		if (cmsg->cmsg_type & cmsg_done) {
974 			err = -EINVAL;
975 			goto out;
976 		}
977 		cmsg_done |= cmsg->cmsg_type;
978 
979 		switch (cmsg->cmsg_type) {
980 		case SCM_IUCV_TRGCLS:
981 			if (cmsg->cmsg_len != CMSG_LEN(TRGCLS_SIZE)) {
982 				err = -EINVAL;
983 				goto out;
984 			}
985 
986 			/* set iucv message target class */
987 			memcpy(&txmsg.class,
988 				(void *) CMSG_DATA(cmsg), TRGCLS_SIZE);
989 
990 			break;
991 
992 		default:
993 			err = -EINVAL;
994 			goto out;
995 		}
996 	}
997 
998 	/* allocate one skb for each iucv message:
999 	 * this is fine for SOCK_SEQPACKET (unless we want to support
1000 	 * segmented records using the MSG_EOR flag), but
1001 	 * for SOCK_STREAM we might want to improve it in future */
1002 	if (iucv->transport == AF_IUCV_TRANS_HIPER) {
1003 		headroom = sizeof(struct af_iucv_trans_hdr) +
1004 			   LL_RESERVED_SPACE(iucv->hs_dev);
1005 		linear = min(len, PAGE_SIZE - headroom);
1006 	} else {
1007 		if (len < PAGE_SIZE) {
1008 			linear = len;
1009 		} else {
1010 			/* In nonlinear "classic" iucv skb,
1011 			 * reserve space for iucv_array
1012 			 */
1013 			headroom = sizeof(struct iucv_array) *
1014 				   (MAX_SKB_FRAGS + 1);
1015 			linear = PAGE_SIZE - headroom;
1016 		}
1017 	}
1018 	skb = sock_alloc_send_pskb(sk, headroom + linear, len - linear,
1019 				   noblock, &err, 0);
1020 	if (!skb)
1021 		goto out;
1022 	if (headroom)
1023 		skb_reserve(skb, headroom);
1024 	skb_put(skb, linear);
1025 	skb->len = len;
1026 	skb->data_len = len - linear;
1027 	err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
1028 	if (err)
1029 		goto fail;
1030 
1031 	/* wait if outstanding messages for iucv path has reached */
1032 	timeo = sock_sndtimeo(sk, noblock);
1033 	err = iucv_sock_wait(sk, iucv_below_msglim(sk), timeo);
1034 	if (err)
1035 		goto fail;
1036 
1037 	/* return -ECONNRESET if the socket is no longer connected */
1038 	if (sk->sk_state != IUCV_CONNECTED) {
1039 		err = -ECONNRESET;
1040 		goto fail;
1041 	}
1042 
1043 	/* increment and save iucv message tag for msg_completion cbk */
1044 	txmsg.tag = iucv->send_tag++;
1045 	IUCV_SKB_CB(skb)->tag = txmsg.tag;
1046 
1047 	if (iucv->transport == AF_IUCV_TRANS_HIPER) {
1048 		atomic_inc(&iucv->msg_sent);
1049 		err = afiucv_hs_send(&txmsg, sk, skb, 0);
1050 		if (err) {
1051 			atomic_dec(&iucv->msg_sent);
1052 			goto out;
1053 		}
1054 	} else { /* Classic VM IUCV transport */
1055 		skb_queue_tail(&iucv->send_skb_q, skb);
1056 		atomic_inc(&iucv->skbs_in_xmit);
1057 
1058 		if (((iucv->path->flags & IUCV_IPRMDATA) & iucv->flags) &&
1059 		    skb->len <= 7) {
1060 			err = iucv_send_iprm(iucv->path, &txmsg, skb);
1061 
1062 			/* on success: there is no message_complete callback */
1063 			/* for an IPRMDATA msg; remove skb from send queue   */
1064 			if (err == 0) {
1065 				atomic_dec(&iucv->skbs_in_xmit);
1066 				skb_unlink(skb, &iucv->send_skb_q);
1067 				consume_skb(skb);
1068 			}
1069 
1070 			/* this error should never happen since the	*/
1071 			/* IUCV_IPRMDATA path flag is set... sever path */
1072 			if (err == 0x15) {
1073 				pr_iucv->path_sever(iucv->path, NULL);
1074 				atomic_dec(&iucv->skbs_in_xmit);
1075 				skb_unlink(skb, &iucv->send_skb_q);
1076 				err = -EPIPE;
1077 				goto fail;
1078 			}
1079 		} else if (skb_is_nonlinear(skb)) {
1080 			struct iucv_array *iba = (struct iucv_array *)skb->head;
1081 			int i;
1082 
1083 			/* skip iucv_array lying in the headroom */
1084 			iba[0].address = virt_to_dma32(skb->data);
1085 			iba[0].length = (u32)skb_headlen(skb);
1086 			for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1087 				skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1088 
1089 				iba[i + 1].address = virt_to_dma32(skb_frag_address(frag));
1090 				iba[i + 1].length = (u32)skb_frag_size(frag);
1091 			}
1092 			err = pr_iucv->message_send(iucv->path, &txmsg,
1093 						    IUCV_IPBUFLST, 0,
1094 						    (void *)iba, skb->len);
1095 		} else { /* non-IPRM Linear skb */
1096 			err = pr_iucv->message_send(iucv->path, &txmsg,
1097 					0, 0, (void *)skb->data, skb->len);
1098 		}
1099 		if (err) {
1100 			if (err == 3) {
1101 				user_id[8] = 0;
1102 				memcpy(user_id, iucv->dst_user_id, 8);
1103 				appl_id[8] = 0;
1104 				memcpy(appl_id, iucv->dst_name, 8);
1105 				pr_err(
1106 		"Application %s on z/VM guest %s exceeds message limit\n",
1107 					appl_id, user_id);
1108 				err = -EAGAIN;
1109 			} else {
1110 				err = -EPIPE;
1111 			}
1112 
1113 			atomic_dec(&iucv->skbs_in_xmit);
1114 			skb_unlink(skb, &iucv->send_skb_q);
1115 			goto fail;
1116 		}
1117 	}
1118 
1119 	release_sock(sk);
1120 	return len;
1121 
1122 fail:
1123 	kfree_skb(skb);
1124 out:
1125 	release_sock(sk);
1126 	return err;
1127 }
1128 
1129 static struct sk_buff *alloc_iucv_recv_skb(unsigned long len)
1130 {
1131 	size_t headroom, linear;
1132 	struct sk_buff *skb;
1133 	int err;
1134 
1135 	if (len < PAGE_SIZE) {
1136 		headroom = 0;
1137 		linear = len;
1138 	} else {
1139 		headroom = sizeof(struct iucv_array) * (MAX_SKB_FRAGS + 1);
1140 		linear = PAGE_SIZE - headroom;
1141 	}
1142 	skb = alloc_skb_with_frags(headroom + linear, len - linear,
1143 				   0, &err, GFP_ATOMIC | GFP_DMA);
1144 	WARN_ONCE(!skb,
1145 		  "alloc of recv iucv skb len=%lu failed with errcode=%d\n",
1146 		  len, err);
1147 	if (skb) {
1148 		if (headroom)
1149 			skb_reserve(skb, headroom);
1150 		skb_put(skb, linear);
1151 		skb->len = len;
1152 		skb->data_len = len - linear;
1153 	}
1154 	return skb;
1155 }
1156 
1157 /* iucv_process_message() - Receive a single outstanding IUCV message
1158  *
1159  * Locking: must be called with message_q.lock held
1160  */
1161 static void iucv_process_message(struct sock *sk, struct sk_buff *skb,
1162 				 struct iucv_path *path,
1163 				 struct iucv_message *msg)
1164 {
1165 	int rc;
1166 	unsigned int len;
1167 
1168 	len = iucv_msg_length(msg);
1169 
1170 	/* store msg target class in the second 4 bytes of skb ctrl buffer */
1171 	/* Note: the first 4 bytes are reserved for msg tag */
1172 	IUCV_SKB_CB(skb)->class = msg->class;
1173 
1174 	/* check for special IPRM messages (e.g. iucv_sock_shutdown) */
1175 	if ((msg->flags & IUCV_IPRMDATA) && len > 7) {
1176 		if (memcmp(msg->rmmsg, iprm_shutdown, 8) == 0) {
1177 			skb->data = NULL;
1178 			skb->len = 0;
1179 		}
1180 	} else {
1181 		if (skb_is_nonlinear(skb)) {
1182 			struct iucv_array *iba = (struct iucv_array *)skb->head;
1183 			int i;
1184 
1185 			iba[0].address = virt_to_dma32(skb->data);
1186 			iba[0].length = (u32)skb_headlen(skb);
1187 			for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1188 				skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1189 
1190 				iba[i + 1].address = virt_to_dma32(skb_frag_address(frag));
1191 				iba[i + 1].length = (u32)skb_frag_size(frag);
1192 			}
1193 			rc = pr_iucv->message_receive(path, msg,
1194 					      IUCV_IPBUFLST,
1195 					      (void *)iba, len, NULL);
1196 		} else {
1197 			rc = pr_iucv->message_receive(path, msg,
1198 					      msg->flags & IUCV_IPRMDATA,
1199 					      skb->data, len, NULL);
1200 		}
1201 		if (rc) {
1202 			kfree_skb(skb);
1203 			return;
1204 		}
1205 		WARN_ON_ONCE(skb->len != len);
1206 	}
1207 
1208 	IUCV_SKB_CB(skb)->offset = 0;
1209 	if (sk_filter(sk, skb)) {
1210 		sk_drops_inc(sk);	/* skb rejected by filter */
1211 		kfree_skb(skb);
1212 		return;
1213 	}
1214 	if (__sock_queue_rcv_skb(sk, skb))	/* handle rcv queue full */
1215 		skb_queue_tail(&iucv_sk(sk)->backlog_skb_q, skb);
1216 }
1217 
1218 /* iucv_process_message_q() - Process outstanding IUCV messages
1219  *
1220  * Locking: must be called with message_q.lock held
1221  */
1222 static void iucv_process_message_q(struct sock *sk)
1223 {
1224 	struct iucv_sock *iucv = iucv_sk(sk);
1225 	struct sk_buff *skb;
1226 	struct sock_msg_q *p, *n;
1227 
1228 	list_for_each_entry_safe(p, n, &iucv->message_q.list, list) {
1229 		skb = alloc_iucv_recv_skb(iucv_msg_length(&p->msg));
1230 		if (!skb)
1231 			break;
1232 		iucv_process_message(sk, skb, p->path, &p->msg);
1233 		list_del(&p->list);
1234 		kfree(p);
1235 		if (!skb_queue_empty(&iucv->backlog_skb_q))
1236 			break;
1237 	}
1238 }
1239 
1240 static int iucv_sock_recvmsg(struct socket *sock, struct msghdr *msg,
1241 			     size_t len, int flags)
1242 {
1243 	struct sock *sk = sock->sk;
1244 	struct iucv_sock *iucv = iucv_sk(sk);
1245 	unsigned int copied, rlen;
1246 	struct sk_buff *skb, *rskb, *cskb;
1247 	bool send_win = false;
1248 	int err = 0;
1249 	u32 offset;
1250 
1251 	if ((sk->sk_state == IUCV_DISCONN) &&
1252 	    skb_queue_empty(&iucv->backlog_skb_q) &&
1253 	    skb_queue_empty(&sk->sk_receive_queue) &&
1254 	    list_empty(&iucv->message_q.list))
1255 		return 0;
1256 
1257 	if (flags & (MSG_OOB))
1258 		return -EOPNOTSUPP;
1259 
1260 	/* receive/dequeue next skb:
1261 	 * the function understands MSG_PEEK and, thus, does not dequeue skb
1262 	 * only refcount is increased.
1263 	 */
1264 	skb = skb_recv_datagram(sk, flags, &err);
1265 	if (!skb) {
1266 		if (sk->sk_shutdown & RCV_SHUTDOWN)
1267 			return 0;
1268 		return err;
1269 	}
1270 
1271 	offset = IUCV_SKB_CB(skb)->offset;
1272 	rlen   = skb->len - offset;		/* real length of skb */
1273 	copied = min_t(unsigned int, rlen, len);
1274 	if (!rlen)
1275 		sk->sk_shutdown = sk->sk_shutdown | RCV_SHUTDOWN;
1276 
1277 	cskb = skb;
1278 	if (skb_copy_datagram_msg(cskb, offset, msg, copied)) {
1279 		err = -EFAULT;
1280 		goto err_out;
1281 	}
1282 
1283 	/* SOCK_SEQPACKET: set MSG_TRUNC if recv buf size is too small */
1284 	if (sk->sk_type == SOCK_SEQPACKET) {
1285 		if (copied < rlen)
1286 			msg->msg_flags |= MSG_TRUNC;
1287 		/* each iucv message contains a complete record */
1288 		msg->msg_flags |= MSG_EOR;
1289 	}
1290 
1291 	/* create control message to store iucv msg target class:
1292 	 * get the trgcls from the control buffer of the skb due to
1293 	 * fragmentation of original iucv message. */
1294 	err = put_cmsg(msg, SOL_IUCV, SCM_IUCV_TRGCLS,
1295 		       sizeof(IUCV_SKB_CB(skb)->class),
1296 		       (void *)&IUCV_SKB_CB(skb)->class);
1297 	if (err)
1298 		goto err_out;
1299 
1300 	/* Mark read part of skb as used */
1301 	if (!(flags & MSG_PEEK)) {
1302 
1303 		/* SOCK_STREAM: re-queue skb if it contains unreceived data */
1304 		if (sk->sk_type == SOCK_STREAM) {
1305 			if (copied < rlen) {
1306 				IUCV_SKB_CB(skb)->offset = offset + copied;
1307 				skb_queue_head(&sk->sk_receive_queue, skb);
1308 				goto done;
1309 			}
1310 		}
1311 
1312 		consume_skb(skb);
1313 		if (iucv->transport == AF_IUCV_TRANS_HIPER) {
1314 			atomic_inc(&iucv->msg_recv);
1315 			if (atomic_read(&iucv->msg_recv) > iucv->msglimit) {
1316 				WARN_ON(1);
1317 				iucv_sock_close(sk);
1318 				return -EFAULT;
1319 			}
1320 		}
1321 
1322 		/* Queue backlog skbs */
1323 		spin_lock_bh(&iucv->message_q.lock);
1324 		rskb = skb_dequeue(&iucv->backlog_skb_q);
1325 		while (rskb) {
1326 			IUCV_SKB_CB(rskb)->offset = 0;
1327 			if (__sock_queue_rcv_skb(sk, rskb)) {
1328 				/* handle rcv queue full */
1329 				skb_queue_head(&iucv->backlog_skb_q,
1330 						rskb);
1331 				break;
1332 			}
1333 			rskb = skb_dequeue(&iucv->backlog_skb_q);
1334 		}
1335 		if (skb_queue_empty(&iucv->backlog_skb_q)) {
1336 			if (!list_empty(&iucv->message_q.list))
1337 				iucv_process_message_q(sk);
1338 			if (iucv->transport == AF_IUCV_TRANS_HIPER &&
1339 			    atomic_read(&iucv->msg_recv) >=
1340 							iucv->msglimit / 2)
1341 				send_win = true;
1342 		}
1343 		spin_unlock_bh(&iucv->message_q.lock);
1344 
1345 		if (send_win) {
1346 			err = iucv_send_ctrl(sk, AF_IUCV_FLAG_WIN);
1347 			if (err) {
1348 				sk->sk_state = IUCV_DISCONN;
1349 				sk->sk_state_change(sk);
1350 			}
1351 		}
1352 	}
1353 
1354 done:
1355 	/* SOCK_SEQPACKET: return real length if MSG_TRUNC is set */
1356 	if (sk->sk_type == SOCK_SEQPACKET && (flags & MSG_TRUNC))
1357 		copied = rlen;
1358 	if (flags & MSG_PEEK)
1359 		skb_unref(skb);
1360 
1361 	return copied;
1362 
1363 err_out:
1364 	if (!(flags & MSG_PEEK))
1365 		skb_queue_head(&sk->sk_receive_queue, skb);
1366 	else
1367 		skb_unref(skb);
1368 
1369 	return err;
1370 }
1371 
1372 static inline __poll_t iucv_accept_poll(struct sock *parent)
1373 {
1374 	struct iucv_sock *isk, *n;
1375 	struct sock *sk;
1376 
1377 	list_for_each_entry_safe(isk, n, &iucv_sk(parent)->accept_q, accept_q) {
1378 		sk = (struct sock *) isk;
1379 
1380 		if (sk->sk_state == IUCV_CONNECTED)
1381 			return EPOLLIN | EPOLLRDNORM;
1382 	}
1383 
1384 	return 0;
1385 }
1386 
1387 static __poll_t iucv_sock_poll(struct file *file, struct socket *sock,
1388 			       poll_table *wait)
1389 {
1390 	struct sock *sk = sock->sk;
1391 	__poll_t mask = 0;
1392 
1393 	sock_poll_wait(file, sock, wait);
1394 
1395 	if (sk->sk_state == IUCV_LISTEN)
1396 		return iucv_accept_poll(sk);
1397 
1398 	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
1399 		mask |= EPOLLERR |
1400 			(sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
1401 
1402 	if (sk->sk_shutdown & RCV_SHUTDOWN)
1403 		mask |= EPOLLRDHUP;
1404 
1405 	if (sk->sk_shutdown == SHUTDOWN_MASK)
1406 		mask |= EPOLLHUP;
1407 
1408 	if (!skb_queue_empty(&sk->sk_receive_queue) ||
1409 	    (sk->sk_shutdown & RCV_SHUTDOWN))
1410 		mask |= EPOLLIN | EPOLLRDNORM;
1411 
1412 	if (sk->sk_state == IUCV_CLOSED)
1413 		mask |= EPOLLHUP;
1414 
1415 	if (sk->sk_state == IUCV_DISCONN)
1416 		mask |= EPOLLIN;
1417 
1418 	if (sock_writeable(sk) && iucv_below_msglim(sk))
1419 		mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
1420 	else
1421 		sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
1422 
1423 	return mask;
1424 }
1425 
1426 static int iucv_sock_shutdown(struct socket *sock, int how)
1427 {
1428 	struct sock *sk = sock->sk;
1429 	struct iucv_sock *iucv = iucv_sk(sk);
1430 	struct iucv_message txmsg;
1431 	int err = 0;
1432 
1433 	how++;
1434 
1435 	if ((how & ~SHUTDOWN_MASK) || !how)
1436 		return -EINVAL;
1437 
1438 	lock_sock(sk);
1439 	switch (sk->sk_state) {
1440 	case IUCV_LISTEN:
1441 	case IUCV_DISCONN:
1442 	case IUCV_CLOSING:
1443 	case IUCV_CLOSED:
1444 		err = -ENOTCONN;
1445 		goto fail;
1446 	default:
1447 		break;
1448 	}
1449 
1450 	if ((how == SEND_SHUTDOWN || how == SHUTDOWN_MASK) &&
1451 	    sk->sk_state == IUCV_CONNECTED) {
1452 		if (iucv->transport == AF_IUCV_TRANS_IUCV) {
1453 			txmsg.class = 0;
1454 			txmsg.tag = 0;
1455 			err = pr_iucv->message_send(iucv->path, &txmsg,
1456 				IUCV_IPRMDATA, 0, (void *) iprm_shutdown, 8);
1457 			if (err) {
1458 				switch (err) {
1459 				case 1:
1460 					err = -ENOTCONN;
1461 					break;
1462 				case 2:
1463 					err = -ECONNRESET;
1464 					break;
1465 				default:
1466 					err = -ENOTCONN;
1467 					break;
1468 				}
1469 			}
1470 		} else
1471 			iucv_send_ctrl(sk, AF_IUCV_FLAG_SHT);
1472 	}
1473 
1474 	sk->sk_shutdown |= how;
1475 	if (how == RCV_SHUTDOWN || how == SHUTDOWN_MASK) {
1476 		if ((iucv->transport == AF_IUCV_TRANS_IUCV) &&
1477 		    iucv->path) {
1478 			err = pr_iucv->path_quiesce(iucv->path, NULL);
1479 			if (err)
1480 				err = -ENOTCONN;
1481 /*			skb_queue_purge(&sk->sk_receive_queue); */
1482 		}
1483 		skb_queue_purge(&sk->sk_receive_queue);
1484 	}
1485 
1486 	/* Wake up anyone sleeping in poll */
1487 	sk->sk_state_change(sk);
1488 
1489 fail:
1490 	release_sock(sk);
1491 	return err;
1492 }
1493 
1494 static int iucv_sock_release(struct socket *sock)
1495 {
1496 	struct sock *sk = sock->sk;
1497 	int err = 0;
1498 
1499 	if (!sk)
1500 		return 0;
1501 
1502 	iucv_sock_close(sk);
1503 
1504 	sock_orphan(sk);
1505 	iucv_sock_kill(sk);
1506 	return err;
1507 }
1508 
1509 /* getsockopt and setsockopt */
1510 static int iucv_sock_setsockopt(struct socket *sock, int level, int optname,
1511 				sockptr_t optval, unsigned int optlen)
1512 {
1513 	struct sock *sk = sock->sk;
1514 	struct iucv_sock *iucv = iucv_sk(sk);
1515 	int val;
1516 	int rc;
1517 
1518 	if (level != SOL_IUCV)
1519 		return -ENOPROTOOPT;
1520 
1521 	if (optlen < sizeof(int))
1522 		return -EINVAL;
1523 
1524 	if (copy_from_sockptr(&val, optval, sizeof(int)))
1525 		return -EFAULT;
1526 
1527 	rc = 0;
1528 
1529 	lock_sock(sk);
1530 	switch (optname) {
1531 	case SO_IPRMDATA_MSG:
1532 		if (val)
1533 			iucv->flags |= IUCV_IPRMDATA;
1534 		else
1535 			iucv->flags &= ~IUCV_IPRMDATA;
1536 		break;
1537 	case SO_MSGLIMIT:
1538 		switch (sk->sk_state) {
1539 		case IUCV_OPEN:
1540 		case IUCV_BOUND:
1541 			if (val < 1 || val > U16_MAX)
1542 				rc = -EINVAL;
1543 			else
1544 				iucv->msglimit = val;
1545 			break;
1546 		default:
1547 			rc = -EINVAL;
1548 			break;
1549 		}
1550 		break;
1551 	default:
1552 		rc = -ENOPROTOOPT;
1553 		break;
1554 	}
1555 	release_sock(sk);
1556 
1557 	return rc;
1558 }
1559 
1560 static int iucv_sock_getsockopt(struct socket *sock, int level, int optname,
1561 				sockopt_t *opt)
1562 {
1563 	struct sock *sk = sock->sk;
1564 	struct iucv_sock *iucv = iucv_sk(sk);
1565 	unsigned int val;
1566 	int len, rc;
1567 
1568 	if (level != SOL_IUCV)
1569 		return -ENOPROTOOPT;
1570 
1571 	len = opt->optlen;
1572 	if (len < 0)
1573 		return -EINVAL;
1574 
1575 	len = min_t(unsigned int, len, sizeof(int));
1576 
1577 	rc = 0;
1578 
1579 	lock_sock(sk);
1580 	switch (optname) {
1581 	case SO_IPRMDATA_MSG:
1582 		val = (iucv->flags & IUCV_IPRMDATA) ? 1 : 0;
1583 		break;
1584 	case SO_MSGLIMIT:
1585 		val = (iucv->path != NULL) ? iucv->path->msglim	/* connected */
1586 					   : iucv->msglimit;	/* default */
1587 		break;
1588 	case SO_MSGSIZE:
1589 		if (sk->sk_state == IUCV_OPEN) {
1590 			rc = -EBADFD;
1591 			break;
1592 		}
1593 		val = (iucv->hs_dev) ? iucv->hs_dev->mtu -
1594 				sizeof(struct af_iucv_trans_hdr) - ETH_HLEN :
1595 				0x7fffffff;
1596 		break;
1597 	default:
1598 		rc = -ENOPROTOOPT;
1599 		break;
1600 	}
1601 	release_sock(sk);
1602 
1603 	if (rc)
1604 		return rc;
1605 
1606 	opt->optlen = len;
1607 	if (copy_to_iter(&val, len, &opt->iter_out) != len)
1608 		return -EFAULT;
1609 
1610 	return 0;
1611 }
1612 
1613 
1614 /* Callback wrappers - called from iucv base support */
1615 static int iucv_callback_connreq(struct iucv_path *path,
1616 				 u8 ipvmid[8], u8 ipuser[16])
1617 {
1618 	unsigned char user_data[16];
1619 	unsigned char nuser_data[16];
1620 	unsigned char src_name[8];
1621 	struct sock *sk, *nsk;
1622 	struct iucv_sock *iucv, *niucv;
1623 	int err;
1624 
1625 	memcpy(src_name, ipuser, 8);
1626 	EBCASC(src_name, 8);
1627 	/* Find out if this path belongs to af_iucv. */
1628 	read_lock(&iucv_sk_list.lock);
1629 	iucv = NULL;
1630 	sk = NULL;
1631 	sk_for_each(sk, &iucv_sk_list.head)
1632 		if (sk->sk_state == IUCV_LISTEN &&
1633 		    !memcmp(&iucv_sk(sk)->src_name, src_name, 8)) {
1634 			/*
1635 			 * Found a listening socket with
1636 			 * src_name == ipuser[0-7].
1637 			 */
1638 			iucv = iucv_sk(sk);
1639 			break;
1640 		}
1641 	read_unlock(&iucv_sk_list.lock);
1642 	if (!iucv)
1643 		/* No socket found, not one of our paths. */
1644 		return -EINVAL;
1645 
1646 	bh_lock_sock(sk);
1647 
1648 	/* Check if parent socket is listening */
1649 	low_nmcpy(user_data, iucv->src_name);
1650 	high_nmcpy(user_data, iucv->dst_name);
1651 	ASCEBC(user_data, sizeof(user_data));
1652 	if (sk->sk_state != IUCV_LISTEN) {
1653 		err = pr_iucv->path_sever(path, user_data);
1654 		iucv_path_free(path);
1655 		goto fail;
1656 	}
1657 
1658 	/* Check for backlog size */
1659 	if (sk_acceptq_is_full(sk)) {
1660 		err = pr_iucv->path_sever(path, user_data);
1661 		iucv_path_free(path);
1662 		goto fail;
1663 	}
1664 
1665 	/* Create the new socket */
1666 	nsk = iucv_sock_alloc(NULL, sk->sk_protocol, GFP_ATOMIC, 0);
1667 	if (!nsk) {
1668 		err = pr_iucv->path_sever(path, user_data);
1669 		iucv_path_free(path);
1670 		goto fail;
1671 	}
1672 
1673 	niucv = iucv_sk(nsk);
1674 	iucv_sock_init(nsk, sk);
1675 	niucv->transport = AF_IUCV_TRANS_IUCV;
1676 	nsk->sk_allocation |= GFP_DMA;
1677 
1678 	/* Set the new iucv_sock */
1679 	memcpy(niucv->dst_name, ipuser + 8, 8);
1680 	EBCASC(niucv->dst_name, 8);
1681 	memcpy(niucv->dst_user_id, ipvmid, 8);
1682 	memcpy(niucv->src_name, iucv->src_name, 8);
1683 	memcpy(niucv->src_user_id, iucv->src_user_id, 8);
1684 	niucv->path = path;
1685 
1686 	/* Call iucv_accept */
1687 	high_nmcpy(nuser_data, ipuser + 8);
1688 	memcpy(nuser_data + 8, niucv->src_name, 8);
1689 	ASCEBC(nuser_data + 8, 8);
1690 
1691 	/* set message limit for path based on msglimit of accepting socket */
1692 	niucv->msglimit = iucv->msglimit;
1693 	path->msglim = iucv->msglimit;
1694 	err = pr_iucv->path_accept(path, &af_iucv_handler, nuser_data, nsk);
1695 	if (err) {
1696 		iucv_sever_path(nsk, 1);
1697 		iucv_sock_kill(nsk);
1698 		goto fail;
1699 	}
1700 
1701 	iucv_accept_enqueue(sk, nsk);
1702 
1703 	/* Wake up accept */
1704 	nsk->sk_state = IUCV_CONNECTED;
1705 	sk->sk_data_ready(sk);
1706 	err = 0;
1707 fail:
1708 	bh_unlock_sock(sk);
1709 	return 0;
1710 }
1711 
1712 static void iucv_callback_connack(struct iucv_path *path, u8 ipuser[16])
1713 {
1714 	struct sock *sk = path->private;
1715 
1716 	sk->sk_state = IUCV_CONNECTED;
1717 	sk->sk_state_change(sk);
1718 }
1719 
1720 static void iucv_callback_rx(struct iucv_path *path, struct iucv_message *msg)
1721 {
1722 	struct sock *sk = path->private;
1723 	struct iucv_sock *iucv = iucv_sk(sk);
1724 	struct sk_buff *skb;
1725 	struct sock_msg_q *save_msg;
1726 	int len;
1727 
1728 	if (sk->sk_shutdown & RCV_SHUTDOWN) {
1729 		pr_iucv->message_reject(path, msg);
1730 		return;
1731 	}
1732 
1733 	spin_lock(&iucv->message_q.lock);
1734 
1735 	if (!list_empty(&iucv->message_q.list) ||
1736 	    !skb_queue_empty(&iucv->backlog_skb_q))
1737 		goto save_message;
1738 
1739 	len = atomic_read(&sk->sk_rmem_alloc);
1740 	len += SKB_TRUESIZE(iucv_msg_length(msg));
1741 	if (len > sk->sk_rcvbuf)
1742 		goto save_message;
1743 
1744 	skb = alloc_iucv_recv_skb(iucv_msg_length(msg));
1745 	if (!skb)
1746 		goto save_message;
1747 
1748 	iucv_process_message(sk, skb, path, msg);
1749 	goto out_unlock;
1750 
1751 save_message:
1752 	save_msg = kzalloc_obj(struct sock_msg_q, GFP_ATOMIC | GFP_DMA);
1753 	if (!save_msg)
1754 		goto out_unlock;
1755 	save_msg->path = path;
1756 	save_msg->msg = *msg;
1757 
1758 	list_add_tail(&save_msg->list, &iucv->message_q.list);
1759 
1760 out_unlock:
1761 	spin_unlock(&iucv->message_q.lock);
1762 }
1763 
1764 static void iucv_callback_txdone(struct iucv_path *path,
1765 				 struct iucv_message *msg)
1766 {
1767 	struct sock *sk = path->private;
1768 	struct sk_buff *this = NULL;
1769 	struct sk_buff_head *list;
1770 	struct sk_buff *list_skb;
1771 	struct iucv_sock *iucv;
1772 	unsigned long flags;
1773 
1774 	iucv = iucv_sk(sk);
1775 	list = &iucv->send_skb_q;
1776 
1777 	bh_lock_sock(sk);
1778 
1779 	spin_lock_irqsave(&list->lock, flags);
1780 	skb_queue_walk(list, list_skb) {
1781 		if (msg->tag == IUCV_SKB_CB(list_skb)->tag) {
1782 			this = list_skb;
1783 			break;
1784 		}
1785 	}
1786 	if (this) {
1787 		atomic_dec(&iucv->skbs_in_xmit);
1788 		__skb_unlink(this, list);
1789 	}
1790 
1791 	spin_unlock_irqrestore(&list->lock, flags);
1792 
1793 	if (this) {
1794 		consume_skb(this);
1795 		/* wake up any process waiting for sending */
1796 		iucv_sock_wake_msglim(sk);
1797 	}
1798 
1799 	if (sk->sk_state == IUCV_CLOSING) {
1800 		if (atomic_read(&iucv->skbs_in_xmit) == 0) {
1801 			sk->sk_state = IUCV_CLOSED;
1802 			sk->sk_state_change(sk);
1803 		}
1804 	}
1805 	bh_unlock_sock(sk);
1806 
1807 }
1808 
1809 static void iucv_callback_connrej(struct iucv_path *path, u8 ipuser[16])
1810 {
1811 	struct sock *sk = path->private;
1812 
1813 	if (sk->sk_state == IUCV_CLOSED)
1814 		return;
1815 
1816 	bh_lock_sock(sk);
1817 	iucv_sever_path(sk, 1);
1818 	sk->sk_state = IUCV_DISCONN;
1819 
1820 	sk->sk_state_change(sk);
1821 	bh_unlock_sock(sk);
1822 }
1823 
1824 /* called if the other communication side shuts down its RECV direction;
1825  * in turn, the callback sets SEND_SHUTDOWN to disable sending of data.
1826  */
1827 static void iucv_callback_shutdown(struct iucv_path *path, u8 ipuser[16])
1828 {
1829 	struct sock *sk = path->private;
1830 
1831 	bh_lock_sock(sk);
1832 	if (sk->sk_state != IUCV_CLOSED) {
1833 		sk->sk_shutdown |= SEND_SHUTDOWN;
1834 		sk->sk_state_change(sk);
1835 	}
1836 	bh_unlock_sock(sk);
1837 }
1838 
1839 static struct iucv_handler af_iucv_handler = {
1840 	.path_pending		= iucv_callback_connreq,
1841 	.path_complete		= iucv_callback_connack,
1842 	.path_severed		= iucv_callback_connrej,
1843 	.message_pending	= iucv_callback_rx,
1844 	.message_complete	= iucv_callback_txdone,
1845 	.path_quiesced		= iucv_callback_shutdown,
1846 };
1847 
1848 /***************** HiperSockets transport callbacks ********************/
1849 static void afiucv_swap_src_dest(struct sk_buff *skb)
1850 {
1851 	struct af_iucv_trans_hdr *trans_hdr = iucv_trans_hdr(skb);
1852 	char tmpID[8];
1853 	char tmpName[8];
1854 
1855 	ASCEBC(trans_hdr->destUserID, sizeof(trans_hdr->destUserID));
1856 	ASCEBC(trans_hdr->destAppName, sizeof(trans_hdr->destAppName));
1857 	ASCEBC(trans_hdr->srcUserID, sizeof(trans_hdr->srcUserID));
1858 	ASCEBC(trans_hdr->srcAppName, sizeof(trans_hdr->srcAppName));
1859 	memcpy(tmpID, trans_hdr->srcUserID, 8);
1860 	memcpy(tmpName, trans_hdr->srcAppName, 8);
1861 	memcpy(trans_hdr->srcUserID, trans_hdr->destUserID, 8);
1862 	memcpy(trans_hdr->srcAppName, trans_hdr->destAppName, 8);
1863 	memcpy(trans_hdr->destUserID, tmpID, 8);
1864 	memcpy(trans_hdr->destAppName, tmpName, 8);
1865 	skb_push(skb, ETH_HLEN);
1866 	memset(skb->data, 0, ETH_HLEN);
1867 }
1868 
1869 /*
1870  * afiucv_hs_callback_syn - react on received SYN
1871  */
1872 static int afiucv_hs_callback_syn(struct sock *sk, struct sk_buff *skb)
1873 {
1874 	struct af_iucv_trans_hdr *trans_hdr = iucv_trans_hdr(skb);
1875 	struct sock *nsk;
1876 	struct iucv_sock *iucv, *niucv;
1877 	int err;
1878 
1879 	iucv = iucv_sk(sk);
1880 	if (!iucv) {
1881 		/* no sock - connection refused */
1882 		afiucv_swap_src_dest(skb);
1883 		trans_hdr->flags = AF_IUCV_FLAG_SYN | AF_IUCV_FLAG_FIN;
1884 		err = dev_queue_xmit(skb);
1885 		goto out;
1886 	}
1887 
1888 	nsk = iucv_sock_alloc(NULL, sk->sk_protocol, GFP_ATOMIC, 0);
1889 	bh_lock_sock(sk);
1890 	if ((sk->sk_state != IUCV_LISTEN) ||
1891 	    sk_acceptq_is_full(sk) ||
1892 	    !nsk) {
1893 		/* error on server socket - connection refused */
1894 		afiucv_swap_src_dest(skb);
1895 		trans_hdr->flags = AF_IUCV_FLAG_SYN | AF_IUCV_FLAG_FIN;
1896 		err = dev_queue_xmit(skb);
1897 		if (nsk)
1898 			iucv_sock_kill(nsk);
1899 		bh_unlock_sock(sk);
1900 		goto out;
1901 	}
1902 
1903 	niucv = iucv_sk(nsk);
1904 	iucv_sock_init(nsk, sk);
1905 	niucv->transport = AF_IUCV_TRANS_HIPER;
1906 	niucv->msglimit = iucv->msglimit;
1907 	if (!trans_hdr->window)
1908 		niucv->msglimit_peer = IUCV_HIPER_MSGLIM_DEFAULT;
1909 	else
1910 		niucv->msglimit_peer = trans_hdr->window;
1911 	memcpy(niucv->dst_name, trans_hdr->srcAppName, 8);
1912 	memcpy(niucv->dst_user_id, trans_hdr->srcUserID, 8);
1913 	memcpy(niucv->src_name, iucv->src_name, 8);
1914 	memcpy(niucv->src_user_id, iucv->src_user_id, 8);
1915 	nsk->sk_bound_dev_if = sk->sk_bound_dev_if;
1916 	niucv->hs_dev = iucv->hs_dev;
1917 	dev_hold(niucv->hs_dev);
1918 	afiucv_swap_src_dest(skb);
1919 	trans_hdr->flags = AF_IUCV_FLAG_SYN | AF_IUCV_FLAG_ACK;
1920 	trans_hdr->window = niucv->msglimit;
1921 	/* if receiver acks the xmit connection is established */
1922 	err = dev_queue_xmit(skb);
1923 	if (!err) {
1924 		iucv_accept_enqueue(sk, nsk);
1925 		nsk->sk_state = IUCV_CONNECTED;
1926 		sk->sk_data_ready(sk);
1927 	} else
1928 		iucv_sock_kill(nsk);
1929 	bh_unlock_sock(sk);
1930 
1931 out:
1932 	return NET_RX_SUCCESS;
1933 }
1934 
1935 /*
1936  * afiucv_hs_callback_synack() - react on received SYN-ACK
1937  */
1938 static int afiucv_hs_callback_synack(struct sock *sk, struct sk_buff *skb)
1939 {
1940 	struct iucv_sock *iucv = iucv_sk(sk);
1941 
1942 	if (!iucv || sk->sk_state != IUCV_BOUND) {
1943 		kfree_skb(skb);
1944 		return NET_RX_SUCCESS;
1945 	}
1946 
1947 	bh_lock_sock(sk);
1948 	iucv->msglimit_peer = iucv_trans_hdr(skb)->window;
1949 	sk->sk_state = IUCV_CONNECTED;
1950 	sk->sk_state_change(sk);
1951 	bh_unlock_sock(sk);
1952 	consume_skb(skb);
1953 	return NET_RX_SUCCESS;
1954 }
1955 
1956 /*
1957  * afiucv_hs_callback_synfin() - react on received SYN_FIN
1958  */
1959 static int afiucv_hs_callback_synfin(struct sock *sk, struct sk_buff *skb)
1960 {
1961 	struct iucv_sock *iucv = iucv_sk(sk);
1962 
1963 	if (!iucv || sk->sk_state != IUCV_BOUND) {
1964 		kfree_skb(skb);
1965 		return NET_RX_SUCCESS;
1966 	}
1967 
1968 	bh_lock_sock(sk);
1969 	sk->sk_state = IUCV_DISCONN;
1970 	sk->sk_state_change(sk);
1971 	bh_unlock_sock(sk);
1972 	consume_skb(skb);
1973 	return NET_RX_SUCCESS;
1974 }
1975 
1976 /*
1977  * afiucv_hs_callback_fin() - react on received FIN
1978  */
1979 static int afiucv_hs_callback_fin(struct sock *sk, struct sk_buff *skb)
1980 {
1981 	struct iucv_sock *iucv = iucv_sk(sk);
1982 
1983 	/* other end of connection closed */
1984 	if (!iucv) {
1985 		kfree_skb(skb);
1986 		return NET_RX_SUCCESS;
1987 	}
1988 
1989 	bh_lock_sock(sk);
1990 	if (sk->sk_state == IUCV_CONNECTED) {
1991 		sk->sk_state = IUCV_DISCONN;
1992 		sk->sk_state_change(sk);
1993 	}
1994 	bh_unlock_sock(sk);
1995 	consume_skb(skb);
1996 	return NET_RX_SUCCESS;
1997 }
1998 
1999 /*
2000  * afiucv_hs_callback_win() - react on received WIN
2001  */
2002 static int afiucv_hs_callback_win(struct sock *sk, struct sk_buff *skb)
2003 {
2004 	struct iucv_sock *iucv = iucv_sk(sk);
2005 
2006 	if (!iucv)
2007 		return NET_RX_SUCCESS;
2008 
2009 	if (sk->sk_state != IUCV_CONNECTED)
2010 		return NET_RX_SUCCESS;
2011 
2012 	atomic_sub(iucv_trans_hdr(skb)->window, &iucv->msg_sent);
2013 	iucv_sock_wake_msglim(sk);
2014 	return NET_RX_SUCCESS;
2015 }
2016 
2017 /*
2018  * afiucv_hs_callback_rx() - react on received data
2019  */
2020 static int afiucv_hs_callback_rx(struct sock *sk, struct sk_buff *skb)
2021 {
2022 	struct iucv_sock *iucv = iucv_sk(sk);
2023 
2024 	if (!iucv) {
2025 		kfree_skb(skb);
2026 		return NET_RX_SUCCESS;
2027 	}
2028 
2029 	if (sk->sk_state != IUCV_CONNECTED) {
2030 		kfree_skb(skb);
2031 		return NET_RX_SUCCESS;
2032 	}
2033 
2034 	if (sk->sk_shutdown & RCV_SHUTDOWN) {
2035 		kfree_skb(skb);
2036 		return NET_RX_SUCCESS;
2037 	}
2038 
2039 	/* write stuff from iucv_msg to skb cb */
2040 	skb_pull(skb, sizeof(struct af_iucv_trans_hdr));
2041 	skb_reset_transport_header(skb);
2042 	skb_reset_network_header(skb);
2043 	IUCV_SKB_CB(skb)->offset = 0;
2044 	if (sk_filter(sk, skb)) {
2045 		sk_drops_inc(sk);	/* skb rejected by filter */
2046 		kfree_skb(skb);
2047 		return NET_RX_SUCCESS;
2048 	}
2049 
2050 	spin_lock(&iucv->message_q.lock);
2051 	if (skb_queue_empty(&iucv->backlog_skb_q)) {
2052 		if (__sock_queue_rcv_skb(sk, skb))
2053 			/* handle rcv queue full */
2054 			skb_queue_tail(&iucv->backlog_skb_q, skb);
2055 	} else
2056 		skb_queue_tail(&iucv_sk(sk)->backlog_skb_q, skb);
2057 	spin_unlock(&iucv->message_q.lock);
2058 	return NET_RX_SUCCESS;
2059 }
2060 
2061 /*
2062  * afiucv_hs_rcv() - base function for arriving data through HiperSockets
2063  *                   transport
2064  *                   called from netif RX softirq
2065  */
2066 static int afiucv_hs_rcv(struct sk_buff *skb, struct net_device *dev,
2067 	struct packet_type *pt, struct net_device *orig_dev)
2068 {
2069 	struct sock *sk;
2070 	struct iucv_sock *iucv;
2071 	struct af_iucv_trans_hdr *trans_hdr;
2072 	int err = NET_RX_SUCCESS;
2073 	char nullstring[8];
2074 
2075 	if (!pskb_may_pull(skb, sizeof(*trans_hdr))) {
2076 		kfree_skb(skb);
2077 		return NET_RX_SUCCESS;
2078 	}
2079 
2080 	trans_hdr = iucv_trans_hdr(skb);
2081 	EBCASC(trans_hdr->destAppName, sizeof(trans_hdr->destAppName));
2082 	EBCASC(trans_hdr->destUserID, sizeof(trans_hdr->destUserID));
2083 	EBCASC(trans_hdr->srcAppName, sizeof(trans_hdr->srcAppName));
2084 	EBCASC(trans_hdr->srcUserID, sizeof(trans_hdr->srcUserID));
2085 	memset(nullstring, 0, sizeof(nullstring));
2086 	iucv = NULL;
2087 	sk = NULL;
2088 	read_lock(&iucv_sk_list.lock);
2089 	sk_for_each(sk, &iucv_sk_list.head) {
2090 		if (iucv_sk(sk)->hs_dev != dev)
2091 			continue;
2092 		if (trans_hdr->flags == AF_IUCV_FLAG_SYN) {
2093 			if ((!memcmp(&iucv_sk(sk)->src_name,
2094 				     trans_hdr->destAppName, 8)) &&
2095 			    (!memcmp(&iucv_sk(sk)->src_user_id,
2096 				     trans_hdr->destUserID, 8)) &&
2097 			    (!memcmp(&iucv_sk(sk)->dst_name, nullstring, 8)) &&
2098 			    (!memcmp(&iucv_sk(sk)->dst_user_id,
2099 				     nullstring, 8))) {
2100 				iucv = iucv_sk(sk);
2101 				break;
2102 			}
2103 		} else {
2104 			if ((!memcmp(&iucv_sk(sk)->src_name,
2105 				     trans_hdr->destAppName, 8)) &&
2106 			    (!memcmp(&iucv_sk(sk)->src_user_id,
2107 				     trans_hdr->destUserID, 8)) &&
2108 			    (!memcmp(&iucv_sk(sk)->dst_name,
2109 				     trans_hdr->srcAppName, 8)) &&
2110 			    (!memcmp(&iucv_sk(sk)->dst_user_id,
2111 				     trans_hdr->srcUserID, 8))) {
2112 				iucv = iucv_sk(sk);
2113 				break;
2114 			}
2115 		}
2116 	}
2117 	if (sk)
2118 		sock_hold(sk);
2119 	read_unlock(&iucv_sk_list.lock);
2120 	if (!iucv)
2121 		sk = NULL;
2122 
2123 	/* no sock
2124 	how should we send with no sock
2125 	1) send without sock no send rc checking?
2126 	2) introduce default sock to handle this cases
2127 
2128 	 SYN -> send SYN|ACK in good case, send SYN|FIN in bad case
2129 	 data -> send FIN
2130 	 SYN|ACK, SYN|FIN, FIN -> no action? */
2131 
2132 	switch (trans_hdr->flags) {
2133 	case AF_IUCV_FLAG_SYN:
2134 		/* connect request */
2135 		err = afiucv_hs_callback_syn(sk, skb);
2136 		break;
2137 	case (AF_IUCV_FLAG_SYN | AF_IUCV_FLAG_ACK):
2138 		/* connect request confirmed */
2139 		err = afiucv_hs_callback_synack(sk, skb);
2140 		break;
2141 	case (AF_IUCV_FLAG_SYN | AF_IUCV_FLAG_FIN):
2142 		/* connect request refused */
2143 		err = afiucv_hs_callback_synfin(sk, skb);
2144 		break;
2145 	case (AF_IUCV_FLAG_FIN):
2146 		/* close request */
2147 		err = afiucv_hs_callback_fin(sk, skb);
2148 		break;
2149 	case (AF_IUCV_FLAG_WIN):
2150 		err = afiucv_hs_callback_win(sk, skb);
2151 		if (skb->len == sizeof(struct af_iucv_trans_hdr)) {
2152 			consume_skb(skb);
2153 			break;
2154 		}
2155 		fallthrough;	/* and receive non-zero length data */
2156 	case (AF_IUCV_FLAG_SHT):
2157 		/* shutdown request */
2158 		fallthrough;	/* and receive zero length data */
2159 	case 0:
2160 		/* plain data frame */
2161 		IUCV_SKB_CB(skb)->class = trans_hdr->iucv_hdr.class;
2162 		err = afiucv_hs_callback_rx(sk, skb);
2163 		break;
2164 	default:
2165 		kfree_skb(skb);
2166 	}
2167 
2168 	if (sk)
2169 		sock_put(sk);
2170 	return err;
2171 }
2172 
2173 /*
2174  * afiucv_hs_callback_txnotify() - handle send notifications from HiperSockets
2175  *                                 transport
2176  */
2177 static void afiucv_hs_callback_txnotify(struct sock *sk, enum iucv_tx_notify n)
2178 {
2179 	struct iucv_sock *iucv = iucv_sk(sk);
2180 
2181 	if (sock_flag(sk, SOCK_ZAPPED))
2182 		return;
2183 
2184 	switch (n) {
2185 	case TX_NOTIFY_OK:
2186 		atomic_dec(&iucv->skbs_in_xmit);
2187 		iucv_sock_wake_msglim(sk);
2188 		break;
2189 	case TX_NOTIFY_PENDING:
2190 		atomic_inc(&iucv->pendings);
2191 		break;
2192 	case TX_NOTIFY_DELAYED_OK:
2193 		atomic_dec(&iucv->skbs_in_xmit);
2194 		if (atomic_dec_return(&iucv->pendings) <= 0)
2195 			iucv_sock_wake_msglim(sk);
2196 		break;
2197 	default:
2198 		atomic_dec(&iucv->skbs_in_xmit);
2199 		if (sk->sk_state == IUCV_CONNECTED) {
2200 			sk->sk_state = IUCV_DISCONN;
2201 			sk->sk_state_change(sk);
2202 		}
2203 	}
2204 
2205 	if (sk->sk_state == IUCV_CLOSING) {
2206 		if (atomic_read(&iucv->skbs_in_xmit) == 0) {
2207 			sk->sk_state = IUCV_CLOSED;
2208 			sk->sk_state_change(sk);
2209 		}
2210 	}
2211 }
2212 
2213 /*
2214  * afiucv_netdev_event: handle netdev notifier chain events
2215  */
2216 static int afiucv_netdev_event(struct notifier_block *this,
2217 			       unsigned long event, void *ptr)
2218 {
2219 	struct net_device *event_dev = netdev_notifier_info_to_dev(ptr);
2220 	struct sock *sk;
2221 	struct iucv_sock *iucv;
2222 
2223 	switch (event) {
2224 	case NETDEV_REBOOT:
2225 	case NETDEV_GOING_DOWN:
2226 		sk_for_each(sk, &iucv_sk_list.head) {
2227 			iucv = iucv_sk(sk);
2228 			if ((iucv->hs_dev == event_dev) &&
2229 			    (sk->sk_state == IUCV_CONNECTED)) {
2230 				if (event == NETDEV_GOING_DOWN)
2231 					iucv_send_ctrl(sk, AF_IUCV_FLAG_FIN);
2232 				sk->sk_state = IUCV_DISCONN;
2233 				sk->sk_state_change(sk);
2234 			}
2235 		}
2236 		break;
2237 	case NETDEV_DOWN:
2238 	case NETDEV_UNREGISTER:
2239 	default:
2240 		break;
2241 	}
2242 	return NOTIFY_DONE;
2243 }
2244 
2245 static struct notifier_block afiucv_netdev_notifier = {
2246 	.notifier_call = afiucv_netdev_event,
2247 };
2248 
2249 static const struct proto_ops iucv_sock_ops = {
2250 	.family		= PF_IUCV,
2251 	.owner		= THIS_MODULE,
2252 	.release	= iucv_sock_release,
2253 	.bind		= iucv_sock_bind,
2254 	.connect	= iucv_sock_connect,
2255 	.listen		= iucv_sock_listen,
2256 	.accept		= iucv_sock_accept,
2257 	.getname	= iucv_sock_getname,
2258 	.sendmsg	= iucv_sock_sendmsg,
2259 	.recvmsg	= iucv_sock_recvmsg,
2260 	.poll		= iucv_sock_poll,
2261 	.ioctl		= sock_no_ioctl,
2262 	.mmap		= sock_no_mmap,
2263 	.socketpair	= sock_no_socketpair,
2264 	.shutdown	= iucv_sock_shutdown,
2265 	.setsockopt	= iucv_sock_setsockopt,
2266 	.getsockopt_iter = iucv_sock_getsockopt,
2267 };
2268 
2269 static int iucv_sock_create(struct net *net, struct socket *sock, int protocol,
2270 			    int kern)
2271 {
2272 	struct sock *sk;
2273 
2274 	if (protocol && protocol != PF_IUCV)
2275 		return -EPROTONOSUPPORT;
2276 
2277 	sock->state = SS_UNCONNECTED;
2278 
2279 	switch (sock->type) {
2280 	case SOCK_STREAM:
2281 	case SOCK_SEQPACKET:
2282 		/* currently, proto ops can handle both sk types */
2283 		sock->ops = &iucv_sock_ops;
2284 		break;
2285 	default:
2286 		return -ESOCKTNOSUPPORT;
2287 	}
2288 
2289 	sk = iucv_sock_alloc(sock, protocol, GFP_KERNEL, kern);
2290 	if (!sk)
2291 		return -ENOMEM;
2292 
2293 	iucv_sock_init(sk, NULL);
2294 
2295 	return 0;
2296 }
2297 
2298 static const struct net_proto_family iucv_sock_family_ops = {
2299 	.family	= AF_IUCV,
2300 	.owner	= THIS_MODULE,
2301 	.create	= iucv_sock_create,
2302 };
2303 
2304 static struct packet_type iucv_packet_type = {
2305 	.type = cpu_to_be16(ETH_P_AF_IUCV),
2306 	.func = afiucv_hs_rcv,
2307 };
2308 
2309 static int __init afiucv_init(void)
2310 {
2311 	int err;
2312 
2313 	if (machine_is_vm() && IS_ENABLED(CONFIG_IUCV)) {
2314 		cpcmd("QUERY USERID", iucv_userid, sizeof(iucv_userid), &err);
2315 		if (unlikely(err)) {
2316 			WARN_ON(err);
2317 			err = -EPROTONOSUPPORT;
2318 			goto out;
2319 		}
2320 
2321 		pr_iucv = &iucv_if;
2322 	} else {
2323 		memset(&iucv_userid, 0, sizeof(iucv_userid));
2324 		pr_iucv = NULL;
2325 	}
2326 
2327 	err = proto_register(&iucv_proto, 0);
2328 	if (err)
2329 		goto out;
2330 	err = sock_register(&iucv_sock_family_ops);
2331 	if (err)
2332 		goto out_proto;
2333 
2334 	if (pr_iucv) {
2335 		err = pr_iucv->iucv_register(&af_iucv_handler, 0);
2336 		if (err)
2337 			goto out_sock;
2338 	}
2339 
2340 	err = register_netdevice_notifier(&afiucv_netdev_notifier);
2341 	if (err)
2342 		goto out_notifier;
2343 
2344 	dev_add_pack(&iucv_packet_type);
2345 	return 0;
2346 
2347 out_notifier:
2348 	if (pr_iucv)
2349 		pr_iucv->iucv_unregister(&af_iucv_handler, 0);
2350 out_sock:
2351 	sock_unregister(PF_IUCV);
2352 out_proto:
2353 	proto_unregister(&iucv_proto);
2354 out:
2355 	return err;
2356 }
2357 
2358 static void __exit afiucv_exit(void)
2359 {
2360 	if (pr_iucv)
2361 		pr_iucv->iucv_unregister(&af_iucv_handler, 0);
2362 
2363 	unregister_netdevice_notifier(&afiucv_netdev_notifier);
2364 	dev_remove_pack(&iucv_packet_type);
2365 	sock_unregister(PF_IUCV);
2366 	proto_unregister(&iucv_proto);
2367 }
2368 
2369 module_init(afiucv_init);
2370 module_exit(afiucv_exit);
2371 
2372 MODULE_AUTHOR("Jennifer Hunt <jenhunt@us.ibm.com>");
2373 MODULE_DESCRIPTION("IUCV Sockets ver " VERSION);
2374 MODULE_VERSION(VERSION);
2375 MODULE_LICENSE("GPL");
2376 MODULE_ALIAS_NETPROTO(PF_IUCV);
2377