xref: /openbmc/linux/net/phonet/pep.c (revision cc698db4)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * File: pep.c
4  *
5  * Phonet pipe protocol end point socket
6  *
7  * Copyright (C) 2008 Nokia Corporation.
8  *
9  * Author: Rémi Denis-Courmont
10  */
11 
12 #include <linux/kernel.h>
13 #include <linux/sched/signal.h>
14 #include <linux/slab.h>
15 #include <linux/socket.h>
16 #include <net/sock.h>
17 #include <net/tcp_states.h>
18 #include <asm/ioctls.h>
19 
20 #include <linux/phonet.h>
21 #include <linux/module.h>
22 #include <net/phonet/phonet.h>
23 #include <net/phonet/pep.h>
24 #include <net/phonet/gprs.h>
25 
26 /* sk_state values:
27  * TCP_CLOSE		sock not in use yet
28  * TCP_CLOSE_WAIT	disconnected pipe
29  * TCP_LISTEN		listening pipe endpoint
30  * TCP_SYN_RECV		connected pipe in disabled state
31  * TCP_ESTABLISHED	connected pipe in enabled state
32  *
33  * pep_sock locking:
34  *  - sk_state, hlist: sock lock needed
35  *  - listener: read only
36  *  - pipe_handle: read only
37  */
38 
39 #define CREDITS_MAX	10
40 #define CREDITS_THR	7
41 
42 #define pep_sb_size(s) (((s) + 5) & ~3) /* 2-bytes head, 32-bits aligned */
43 
44 /* Get the next TLV sub-block. */
45 static unsigned char *pep_get_sb(struct sk_buff *skb, u8 *ptype, u8 *plen,
46 					void *buf)
47 {
48 	void *data = NULL;
49 	struct {
50 		u8 sb_type;
51 		u8 sb_len;
52 	} *ph, h;
53 	int buflen = *plen;
54 
55 	ph = skb_header_pointer(skb, 0, 2, &h);
56 	if (ph == NULL || ph->sb_len < 2 || !pskb_may_pull(skb, ph->sb_len))
57 		return NULL;
58 	ph->sb_len -= 2;
59 	*ptype = ph->sb_type;
60 	*plen = ph->sb_len;
61 
62 	if (buflen > ph->sb_len)
63 		buflen = ph->sb_len;
64 	data = skb_header_pointer(skb, 2, buflen, buf);
65 	__skb_pull(skb, 2 + ph->sb_len);
66 	return data;
67 }
68 
69 static struct sk_buff *pep_alloc_skb(struct sock *sk, const void *payload,
70 					int len, gfp_t priority)
71 {
72 	struct sk_buff *skb = alloc_skb(MAX_PNPIPE_HEADER + len, priority);
73 	if (!skb)
74 		return NULL;
75 	skb_set_owner_w(skb, sk);
76 
77 	skb_reserve(skb, MAX_PNPIPE_HEADER);
78 	__skb_put(skb, len);
79 	skb_copy_to_linear_data(skb, payload, len);
80 	__skb_push(skb, sizeof(struct pnpipehdr));
81 	skb_reset_transport_header(skb);
82 	return skb;
83 }
84 
85 static int pep_reply(struct sock *sk, struct sk_buff *oskb, u8 code,
86 			const void *data, int len, gfp_t priority)
87 {
88 	const struct pnpipehdr *oph = pnp_hdr(oskb);
89 	struct pnpipehdr *ph;
90 	struct sk_buff *skb;
91 	struct sockaddr_pn peer;
92 
93 	skb = pep_alloc_skb(sk, data, len, priority);
94 	if (!skb)
95 		return -ENOMEM;
96 
97 	ph = pnp_hdr(skb);
98 	ph->utid = oph->utid;
99 	ph->message_id = oph->message_id + 1; /* REQ -> RESP */
100 	ph->pipe_handle = oph->pipe_handle;
101 	ph->error_code = code;
102 
103 	pn_skb_get_src_sockaddr(oskb, &peer);
104 	return pn_skb_send(sk, skb, &peer);
105 }
106 
107 static int pep_indicate(struct sock *sk, u8 id, u8 code,
108 			const void *data, int len, gfp_t priority)
109 {
110 	struct pep_sock *pn = pep_sk(sk);
111 	struct pnpipehdr *ph;
112 	struct sk_buff *skb;
113 
114 	skb = pep_alloc_skb(sk, data, len, priority);
115 	if (!skb)
116 		return -ENOMEM;
117 
118 	ph = pnp_hdr(skb);
119 	ph->utid = 0;
120 	ph->message_id = id;
121 	ph->pipe_handle = pn->pipe_handle;
122 	ph->error_code = code;
123 	return pn_skb_send(sk, skb, NULL);
124 }
125 
126 #define PAD 0x00
127 
128 static int pipe_handler_request(struct sock *sk, u8 id, u8 code,
129 				const void *data, int len)
130 {
131 	struct pep_sock *pn = pep_sk(sk);
132 	struct pnpipehdr *ph;
133 	struct sk_buff *skb;
134 
135 	skb = pep_alloc_skb(sk, data, len, GFP_KERNEL);
136 	if (!skb)
137 		return -ENOMEM;
138 
139 	ph = pnp_hdr(skb);
140 	ph->utid = id; /* whatever */
141 	ph->message_id = id;
142 	ph->pipe_handle = pn->pipe_handle;
143 	ph->error_code = code;
144 	return pn_skb_send(sk, skb, NULL);
145 }
146 
147 static int pipe_handler_send_created_ind(struct sock *sk)
148 {
149 	struct pep_sock *pn = pep_sk(sk);
150 	u8 data[4] = {
151 		PN_PIPE_SB_NEGOTIATED_FC, pep_sb_size(2),
152 		pn->tx_fc, pn->rx_fc,
153 	};
154 
155 	return pep_indicate(sk, PNS_PIPE_CREATED_IND, 1 /* sub-blocks */,
156 				data, 4, GFP_ATOMIC);
157 }
158 
159 static int pep_accept_conn(struct sock *sk, struct sk_buff *skb)
160 {
161 	static const u8 data[20] = {
162 		PAD, PAD, PAD, 2 /* sub-blocks */,
163 		PN_PIPE_SB_REQUIRED_FC_TX, pep_sb_size(5), 3, PAD,
164 			PN_MULTI_CREDIT_FLOW_CONTROL,
165 			PN_ONE_CREDIT_FLOW_CONTROL,
166 			PN_LEGACY_FLOW_CONTROL,
167 			PAD,
168 		PN_PIPE_SB_PREFERRED_FC_RX, pep_sb_size(5), 3, PAD,
169 			PN_MULTI_CREDIT_FLOW_CONTROL,
170 			PN_ONE_CREDIT_FLOW_CONTROL,
171 			PN_LEGACY_FLOW_CONTROL,
172 			PAD,
173 	};
174 
175 	might_sleep();
176 	return pep_reply(sk, skb, PN_PIPE_NO_ERROR, data, sizeof(data),
177 				GFP_KERNEL);
178 }
179 
180 static int pep_reject_conn(struct sock *sk, struct sk_buff *skb, u8 code,
181 				gfp_t priority)
182 {
183 	static const u8 data[4] = { PAD, PAD, PAD, 0 /* sub-blocks */ };
184 	WARN_ON(code == PN_PIPE_NO_ERROR);
185 	return pep_reply(sk, skb, code, data, sizeof(data), priority);
186 }
187 
188 /* Control requests are not sent by the pipe service and have a specific
189  * message format. */
190 static int pep_ctrlreq_error(struct sock *sk, struct sk_buff *oskb, u8 code,
191 				gfp_t priority)
192 {
193 	const struct pnpipehdr *oph = pnp_hdr(oskb);
194 	struct sk_buff *skb;
195 	struct pnpipehdr *ph;
196 	struct sockaddr_pn dst;
197 	u8 data[4] = {
198 		oph->pep_type, /* PEP type */
199 		code, /* error code, at an unusual offset */
200 		PAD, PAD,
201 	};
202 
203 	skb = pep_alloc_skb(sk, data, 4, priority);
204 	if (!skb)
205 		return -ENOMEM;
206 
207 	ph = pnp_hdr(skb);
208 	ph->utid = oph->utid;
209 	ph->message_id = PNS_PEP_CTRL_RESP;
210 	ph->pipe_handle = oph->pipe_handle;
211 	ph->data0 = oph->data[0]; /* CTRL id */
212 
213 	pn_skb_get_src_sockaddr(oskb, &dst);
214 	return pn_skb_send(sk, skb, &dst);
215 }
216 
217 static int pipe_snd_status(struct sock *sk, u8 type, u8 status, gfp_t priority)
218 {
219 	u8 data[4] = { type, PAD, PAD, status };
220 
221 	return pep_indicate(sk, PNS_PEP_STATUS_IND, PN_PEP_TYPE_COMMON,
222 				data, 4, priority);
223 }
224 
225 /* Send our RX flow control information to the sender.
226  * Socket must be locked. */
227 static void pipe_grant_credits(struct sock *sk, gfp_t priority)
228 {
229 	struct pep_sock *pn = pep_sk(sk);
230 
231 	BUG_ON(sk->sk_state != TCP_ESTABLISHED);
232 
233 	switch (pn->rx_fc) {
234 	case PN_LEGACY_FLOW_CONTROL: /* TODO */
235 		break;
236 	case PN_ONE_CREDIT_FLOW_CONTROL:
237 		if (pipe_snd_status(sk, PN_PEP_IND_FLOW_CONTROL,
238 					PEP_IND_READY, priority) == 0)
239 			pn->rx_credits = 1;
240 		break;
241 	case PN_MULTI_CREDIT_FLOW_CONTROL:
242 		if ((pn->rx_credits + CREDITS_THR) > CREDITS_MAX)
243 			break;
244 		if (pipe_snd_status(sk, PN_PEP_IND_ID_MCFC_GRANT_CREDITS,
245 					CREDITS_MAX - pn->rx_credits,
246 					priority) == 0)
247 			pn->rx_credits = CREDITS_MAX;
248 		break;
249 	}
250 }
251 
252 static int pipe_rcv_status(struct sock *sk, struct sk_buff *skb)
253 {
254 	struct pep_sock *pn = pep_sk(sk);
255 	struct pnpipehdr *hdr;
256 	int wake = 0;
257 
258 	if (!pskb_may_pull(skb, sizeof(*hdr) + 4))
259 		return -EINVAL;
260 
261 	hdr = pnp_hdr(skb);
262 	if (hdr->pep_type != PN_PEP_TYPE_COMMON) {
263 		net_dbg_ratelimited("Phonet unknown PEP type: %u\n",
264 				    (unsigned int)hdr->pep_type);
265 		return -EOPNOTSUPP;
266 	}
267 
268 	switch (hdr->data[0]) {
269 	case PN_PEP_IND_FLOW_CONTROL:
270 		switch (pn->tx_fc) {
271 		case PN_LEGACY_FLOW_CONTROL:
272 			switch (hdr->data[3]) {
273 			case PEP_IND_BUSY:
274 				atomic_set(&pn->tx_credits, 0);
275 				break;
276 			case PEP_IND_READY:
277 				atomic_set(&pn->tx_credits, wake = 1);
278 				break;
279 			}
280 			break;
281 		case PN_ONE_CREDIT_FLOW_CONTROL:
282 			if (hdr->data[3] == PEP_IND_READY)
283 				atomic_set(&pn->tx_credits, wake = 1);
284 			break;
285 		}
286 		break;
287 
288 	case PN_PEP_IND_ID_MCFC_GRANT_CREDITS:
289 		if (pn->tx_fc != PN_MULTI_CREDIT_FLOW_CONTROL)
290 			break;
291 		atomic_add(wake = hdr->data[3], &pn->tx_credits);
292 		break;
293 
294 	default:
295 		net_dbg_ratelimited("Phonet unknown PEP indication: %u\n",
296 				    (unsigned int)hdr->data[0]);
297 		return -EOPNOTSUPP;
298 	}
299 	if (wake)
300 		sk->sk_write_space(sk);
301 	return 0;
302 }
303 
304 static int pipe_rcv_created(struct sock *sk, struct sk_buff *skb)
305 {
306 	struct pep_sock *pn = pep_sk(sk);
307 	struct pnpipehdr *hdr = pnp_hdr(skb);
308 	u8 n_sb = hdr->data0;
309 
310 	pn->rx_fc = pn->tx_fc = PN_LEGACY_FLOW_CONTROL;
311 	__skb_pull(skb, sizeof(*hdr));
312 	while (n_sb > 0) {
313 		u8 type, buf[2], len = sizeof(buf);
314 		u8 *data = pep_get_sb(skb, &type, &len, buf);
315 
316 		if (data == NULL)
317 			return -EINVAL;
318 		switch (type) {
319 		case PN_PIPE_SB_NEGOTIATED_FC:
320 			if (len < 2 || (data[0] | data[1]) > 3)
321 				break;
322 			pn->tx_fc = data[0] & 3;
323 			pn->rx_fc = data[1] & 3;
324 			break;
325 		}
326 		n_sb--;
327 	}
328 	return 0;
329 }
330 
331 /* Queue an skb to a connected sock.
332  * Socket lock must be held. */
333 static int pipe_do_rcv(struct sock *sk, struct sk_buff *skb)
334 {
335 	struct pep_sock *pn = pep_sk(sk);
336 	struct pnpipehdr *hdr = pnp_hdr(skb);
337 	struct sk_buff_head *queue;
338 	int err = 0;
339 
340 	BUG_ON(sk->sk_state == TCP_CLOSE_WAIT);
341 
342 	switch (hdr->message_id) {
343 	case PNS_PEP_CONNECT_REQ:
344 		pep_reject_conn(sk, skb, PN_PIPE_ERR_PEP_IN_USE, GFP_ATOMIC);
345 		break;
346 
347 	case PNS_PEP_DISCONNECT_REQ:
348 		pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC);
349 		sk->sk_state = TCP_CLOSE_WAIT;
350 		if (!sock_flag(sk, SOCK_DEAD))
351 			sk->sk_state_change(sk);
352 		break;
353 
354 	case PNS_PEP_ENABLE_REQ:
355 		/* Wait for PNS_PIPE_(ENABLED|REDIRECTED)_IND */
356 		pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC);
357 		break;
358 
359 	case PNS_PEP_RESET_REQ:
360 		switch (hdr->state_after_reset) {
361 		case PN_PIPE_DISABLE:
362 			pn->init_enable = 0;
363 			break;
364 		case PN_PIPE_ENABLE:
365 			pn->init_enable = 1;
366 			break;
367 		default: /* not allowed to send an error here!? */
368 			err = -EINVAL;
369 			goto out;
370 		}
371 		fallthrough;
372 	case PNS_PEP_DISABLE_REQ:
373 		atomic_set(&pn->tx_credits, 0);
374 		pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC);
375 		break;
376 
377 	case PNS_PEP_CTRL_REQ:
378 		if (skb_queue_len(&pn->ctrlreq_queue) >= PNPIPE_CTRLREQ_MAX) {
379 			atomic_inc(&sk->sk_drops);
380 			break;
381 		}
382 		__skb_pull(skb, 4);
383 		queue = &pn->ctrlreq_queue;
384 		goto queue;
385 
386 	case PNS_PIPE_ALIGNED_DATA:
387 		__skb_pull(skb, 1);
388 		fallthrough;
389 	case PNS_PIPE_DATA:
390 		__skb_pull(skb, 3); /* Pipe data header */
391 		if (!pn_flow_safe(pn->rx_fc)) {
392 			err = sock_queue_rcv_skb(sk, skb);
393 			if (!err)
394 				return NET_RX_SUCCESS;
395 			err = -ENOBUFS;
396 			break;
397 		}
398 
399 		if (pn->rx_credits == 0) {
400 			atomic_inc(&sk->sk_drops);
401 			err = -ENOBUFS;
402 			break;
403 		}
404 		pn->rx_credits--;
405 		queue = &sk->sk_receive_queue;
406 		goto queue;
407 
408 	case PNS_PEP_STATUS_IND:
409 		pipe_rcv_status(sk, skb);
410 		break;
411 
412 	case PNS_PIPE_REDIRECTED_IND:
413 		err = pipe_rcv_created(sk, skb);
414 		break;
415 
416 	case PNS_PIPE_CREATED_IND:
417 		err = pipe_rcv_created(sk, skb);
418 		if (err)
419 			break;
420 		fallthrough;
421 	case PNS_PIPE_RESET_IND:
422 		if (!pn->init_enable)
423 			break;
424 		fallthrough;
425 	case PNS_PIPE_ENABLED_IND:
426 		if (!pn_flow_safe(pn->tx_fc)) {
427 			atomic_set(&pn->tx_credits, 1);
428 			sk->sk_write_space(sk);
429 		}
430 		if (sk->sk_state == TCP_ESTABLISHED)
431 			break; /* Nothing to do */
432 		sk->sk_state = TCP_ESTABLISHED;
433 		pipe_grant_credits(sk, GFP_ATOMIC);
434 		break;
435 
436 	case PNS_PIPE_DISABLED_IND:
437 		sk->sk_state = TCP_SYN_RECV;
438 		pn->rx_credits = 0;
439 		break;
440 
441 	default:
442 		net_dbg_ratelimited("Phonet unknown PEP message: %u\n",
443 				    hdr->message_id);
444 		err = -EINVAL;
445 	}
446 out:
447 	kfree_skb(skb);
448 	return (err == -ENOBUFS) ? NET_RX_DROP : NET_RX_SUCCESS;
449 
450 queue:
451 	skb->dev = NULL;
452 	skb_set_owner_r(skb, sk);
453 	skb_queue_tail(queue, skb);
454 	if (!sock_flag(sk, SOCK_DEAD))
455 		sk->sk_data_ready(sk);
456 	return NET_RX_SUCCESS;
457 }
458 
459 /* Destroy connected sock. */
460 static void pipe_destruct(struct sock *sk)
461 {
462 	struct pep_sock *pn = pep_sk(sk);
463 
464 	skb_queue_purge(&sk->sk_receive_queue);
465 	skb_queue_purge(&pn->ctrlreq_queue);
466 }
467 
468 static u8 pipe_negotiate_fc(const u8 *fcs, unsigned int n)
469 {
470 	unsigned int i;
471 	u8 final_fc = PN_NO_FLOW_CONTROL;
472 
473 	for (i = 0; i < n; i++) {
474 		u8 fc = fcs[i];
475 
476 		if (fc > final_fc && fc < PN_MAX_FLOW_CONTROL)
477 			final_fc = fc;
478 	}
479 	return final_fc;
480 }
481 
482 static int pep_connresp_rcv(struct sock *sk, struct sk_buff *skb)
483 {
484 	struct pep_sock *pn = pep_sk(sk);
485 	struct pnpipehdr *hdr;
486 	u8 n_sb;
487 
488 	if (!pskb_pull(skb, sizeof(*hdr) + 4))
489 		return -EINVAL;
490 
491 	hdr = pnp_hdr(skb);
492 	if (hdr->error_code != PN_PIPE_NO_ERROR)
493 		return -ECONNREFUSED;
494 
495 	/* Parse sub-blocks */
496 	n_sb = hdr->data[3];
497 	while (n_sb > 0) {
498 		u8 type, buf[6], len = sizeof(buf);
499 		const u8 *data = pep_get_sb(skb, &type, &len, buf);
500 
501 		if (data == NULL)
502 			return -EINVAL;
503 
504 		switch (type) {
505 		case PN_PIPE_SB_REQUIRED_FC_TX:
506 			if (len < 2 || len < data[0])
507 				break;
508 			pn->tx_fc = pipe_negotiate_fc(data + 2, len - 2);
509 			break;
510 
511 		case PN_PIPE_SB_PREFERRED_FC_RX:
512 			if (len < 2 || len < data[0])
513 				break;
514 			pn->rx_fc = pipe_negotiate_fc(data + 2, len - 2);
515 			break;
516 
517 		}
518 		n_sb--;
519 	}
520 
521 	return pipe_handler_send_created_ind(sk);
522 }
523 
524 static int pep_enableresp_rcv(struct sock *sk, struct sk_buff *skb)
525 {
526 	struct pnpipehdr *hdr = pnp_hdr(skb);
527 
528 	if (hdr->error_code != PN_PIPE_NO_ERROR)
529 		return -ECONNREFUSED;
530 
531 	return pep_indicate(sk, PNS_PIPE_ENABLED_IND, 0 /* sub-blocks */,
532 		NULL, 0, GFP_ATOMIC);
533 
534 }
535 
536 static void pipe_start_flow_control(struct sock *sk)
537 {
538 	struct pep_sock *pn = pep_sk(sk);
539 
540 	if (!pn_flow_safe(pn->tx_fc)) {
541 		atomic_set(&pn->tx_credits, 1);
542 		sk->sk_write_space(sk);
543 	}
544 	pipe_grant_credits(sk, GFP_ATOMIC);
545 }
546 
547 /* Queue an skb to an actively connected sock.
548  * Socket lock must be held. */
549 static int pipe_handler_do_rcv(struct sock *sk, struct sk_buff *skb)
550 {
551 	struct pep_sock *pn = pep_sk(sk);
552 	struct pnpipehdr *hdr = pnp_hdr(skb);
553 	int err = NET_RX_SUCCESS;
554 
555 	switch (hdr->message_id) {
556 	case PNS_PIPE_ALIGNED_DATA:
557 		__skb_pull(skb, 1);
558 		fallthrough;
559 	case PNS_PIPE_DATA:
560 		__skb_pull(skb, 3); /* Pipe data header */
561 		if (!pn_flow_safe(pn->rx_fc)) {
562 			err = sock_queue_rcv_skb(sk, skb);
563 			if (!err)
564 				return NET_RX_SUCCESS;
565 			err = NET_RX_DROP;
566 			break;
567 		}
568 
569 		if (pn->rx_credits == 0) {
570 			atomic_inc(&sk->sk_drops);
571 			err = NET_RX_DROP;
572 			break;
573 		}
574 		pn->rx_credits--;
575 		skb->dev = NULL;
576 		skb_set_owner_r(skb, sk);
577 		skb_queue_tail(&sk->sk_receive_queue, skb);
578 		if (!sock_flag(sk, SOCK_DEAD))
579 			sk->sk_data_ready(sk);
580 		return NET_RX_SUCCESS;
581 
582 	case PNS_PEP_CONNECT_RESP:
583 		if (sk->sk_state != TCP_SYN_SENT)
584 			break;
585 		if (!sock_flag(sk, SOCK_DEAD))
586 			sk->sk_state_change(sk);
587 		if (pep_connresp_rcv(sk, skb)) {
588 			sk->sk_state = TCP_CLOSE_WAIT;
589 			break;
590 		}
591 		if (pn->init_enable == PN_PIPE_DISABLE)
592 			sk->sk_state = TCP_SYN_RECV;
593 		else {
594 			sk->sk_state = TCP_ESTABLISHED;
595 			pipe_start_flow_control(sk);
596 		}
597 		break;
598 
599 	case PNS_PEP_ENABLE_RESP:
600 		if (sk->sk_state != TCP_SYN_SENT)
601 			break;
602 
603 		if (pep_enableresp_rcv(sk, skb)) {
604 			sk->sk_state = TCP_CLOSE_WAIT;
605 			break;
606 		}
607 
608 		sk->sk_state = TCP_ESTABLISHED;
609 		pipe_start_flow_control(sk);
610 		break;
611 
612 	case PNS_PEP_DISCONNECT_RESP:
613 		/* sock should already be dead, nothing to do */
614 		break;
615 
616 	case PNS_PEP_STATUS_IND:
617 		pipe_rcv_status(sk, skb);
618 		break;
619 	}
620 	kfree_skb(skb);
621 	return err;
622 }
623 
624 /* Listening sock must be locked */
625 static struct sock *pep_find_pipe(const struct hlist_head *hlist,
626 					const struct sockaddr_pn *dst,
627 					u8 pipe_handle)
628 {
629 	struct sock *sknode;
630 	u16 dobj = pn_sockaddr_get_object(dst);
631 
632 	sk_for_each(sknode, hlist) {
633 		struct pep_sock *pnnode = pep_sk(sknode);
634 
635 		/* Ports match, but addresses might not: */
636 		if (pnnode->pn_sk.sobject != dobj)
637 			continue;
638 		if (pnnode->pipe_handle != pipe_handle)
639 			continue;
640 		if (sknode->sk_state == TCP_CLOSE_WAIT)
641 			continue;
642 
643 		sock_hold(sknode);
644 		return sknode;
645 	}
646 	return NULL;
647 }
648 
649 /*
650  * Deliver an skb to a listening sock.
651  * Socket lock must be held.
652  * We then queue the skb to the right connected sock (if any).
653  */
654 static int pep_do_rcv(struct sock *sk, struct sk_buff *skb)
655 {
656 	struct pep_sock *pn = pep_sk(sk);
657 	struct sock *sknode;
658 	struct pnpipehdr *hdr;
659 	struct sockaddr_pn dst;
660 	u8 pipe_handle;
661 
662 	if (!pskb_may_pull(skb, sizeof(*hdr)))
663 		goto drop;
664 
665 	hdr = pnp_hdr(skb);
666 	pipe_handle = hdr->pipe_handle;
667 	if (pipe_handle == PN_PIPE_INVALID_HANDLE)
668 		goto drop;
669 
670 	pn_skb_get_dst_sockaddr(skb, &dst);
671 
672 	/* Look for an existing pipe handle */
673 	sknode = pep_find_pipe(&pn->hlist, &dst, pipe_handle);
674 	if (sknode)
675 		return sk_receive_skb(sknode, skb, 1);
676 
677 	switch (hdr->message_id) {
678 	case PNS_PEP_CONNECT_REQ:
679 		if (sk->sk_state != TCP_LISTEN || sk_acceptq_is_full(sk)) {
680 			pep_reject_conn(sk, skb, PN_PIPE_ERR_PEP_IN_USE,
681 					GFP_ATOMIC);
682 			break;
683 		}
684 		skb_queue_head(&sk->sk_receive_queue, skb);
685 		sk_acceptq_added(sk);
686 		if (!sock_flag(sk, SOCK_DEAD))
687 			sk->sk_data_ready(sk);
688 		return NET_RX_SUCCESS;
689 
690 	case PNS_PEP_DISCONNECT_REQ:
691 		pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC);
692 		break;
693 
694 	case PNS_PEP_CTRL_REQ:
695 		pep_ctrlreq_error(sk, skb, PN_PIPE_INVALID_HANDLE, GFP_ATOMIC);
696 		break;
697 
698 	case PNS_PEP_RESET_REQ:
699 	case PNS_PEP_ENABLE_REQ:
700 	case PNS_PEP_DISABLE_REQ:
701 		/* invalid handle is not even allowed here! */
702 		break;
703 
704 	default:
705 		if ((1 << sk->sk_state)
706 				& ~(TCPF_CLOSE|TCPF_LISTEN|TCPF_CLOSE_WAIT))
707 			/* actively connected socket */
708 			return pipe_handler_do_rcv(sk, skb);
709 	}
710 drop:
711 	kfree_skb(skb);
712 	return NET_RX_SUCCESS;
713 }
714 
715 static int pipe_do_remove(struct sock *sk)
716 {
717 	struct pep_sock *pn = pep_sk(sk);
718 	struct pnpipehdr *ph;
719 	struct sk_buff *skb;
720 
721 	skb = pep_alloc_skb(sk, NULL, 0, GFP_KERNEL);
722 	if (!skb)
723 		return -ENOMEM;
724 
725 	ph = pnp_hdr(skb);
726 	ph->utid = 0;
727 	ph->message_id = PNS_PIPE_REMOVE_REQ;
728 	ph->pipe_handle = pn->pipe_handle;
729 	ph->data0 = PAD;
730 	return pn_skb_send(sk, skb, NULL);
731 }
732 
733 /* associated socket ceases to exist */
734 static void pep_sock_close(struct sock *sk, long timeout)
735 {
736 	struct pep_sock *pn = pep_sk(sk);
737 	int ifindex = 0;
738 
739 	sock_hold(sk); /* keep a reference after sk_common_release() */
740 	sk_common_release(sk);
741 
742 	lock_sock(sk);
743 	if ((1 << sk->sk_state) & (TCPF_SYN_RECV|TCPF_ESTABLISHED)) {
744 		if (sk->sk_backlog_rcv == pipe_do_rcv)
745 			/* Forcefully remove dangling Phonet pipe */
746 			pipe_do_remove(sk);
747 		else
748 			pipe_handler_request(sk, PNS_PEP_DISCONNECT_REQ, PAD,
749 						NULL, 0);
750 	}
751 	sk->sk_state = TCP_CLOSE;
752 
753 	ifindex = pn->ifindex;
754 	pn->ifindex = 0;
755 	release_sock(sk);
756 
757 	if (ifindex)
758 		gprs_detach(sk);
759 	sock_put(sk);
760 }
761 
762 static struct sock *pep_sock_accept(struct sock *sk, int flags, int *errp,
763 				    bool kern)
764 {
765 	struct pep_sock *pn = pep_sk(sk), *newpn;
766 	struct sock *newsk = NULL;
767 	struct sk_buff *skb;
768 	struct pnpipehdr *hdr;
769 	struct sockaddr_pn dst, src;
770 	int err;
771 	u16 peer_type;
772 	u8 pipe_handle, enabled, n_sb;
773 	u8 aligned = 0;
774 
775 	skb = skb_recv_datagram(sk, (flags & O_NONBLOCK) ? MSG_DONTWAIT : 0,
776 				errp);
777 	if (!skb)
778 		return NULL;
779 
780 	lock_sock(sk);
781 	if (sk->sk_state != TCP_LISTEN) {
782 		err = -EINVAL;
783 		goto drop;
784 	}
785 	sk_acceptq_removed(sk);
786 
787 	err = -EPROTO;
788 	if (!pskb_may_pull(skb, sizeof(*hdr) + 4))
789 		goto drop;
790 
791 	hdr = pnp_hdr(skb);
792 	pipe_handle = hdr->pipe_handle;
793 	switch (hdr->state_after_connect) {
794 	case PN_PIPE_DISABLE:
795 		enabled = 0;
796 		break;
797 	case PN_PIPE_ENABLE:
798 		enabled = 1;
799 		break;
800 	default:
801 		pep_reject_conn(sk, skb, PN_PIPE_ERR_INVALID_PARAM,
802 				GFP_KERNEL);
803 		goto drop;
804 	}
805 	peer_type = hdr->other_pep_type << 8;
806 
807 	/* Parse sub-blocks (options) */
808 	n_sb = hdr->data[3];
809 	while (n_sb > 0) {
810 		u8 type, buf[1], len = sizeof(buf);
811 		const u8 *data = pep_get_sb(skb, &type, &len, buf);
812 
813 		if (data == NULL)
814 			goto drop;
815 		switch (type) {
816 		case PN_PIPE_SB_CONNECT_REQ_PEP_SUB_TYPE:
817 			if (len < 1)
818 				goto drop;
819 			peer_type = (peer_type & 0xff00) | data[0];
820 			break;
821 		case PN_PIPE_SB_ALIGNED_DATA:
822 			aligned = data[0] != 0;
823 			break;
824 		}
825 		n_sb--;
826 	}
827 
828 	/* Check for duplicate pipe handle */
829 	newsk = pep_find_pipe(&pn->hlist, &dst, pipe_handle);
830 	if (unlikely(newsk)) {
831 		__sock_put(newsk);
832 		newsk = NULL;
833 		pep_reject_conn(sk, skb, PN_PIPE_ERR_PEP_IN_USE, GFP_KERNEL);
834 		goto drop;
835 	}
836 
837 	/* Create a new to-be-accepted sock */
838 	newsk = sk_alloc(sock_net(sk), PF_PHONET, GFP_KERNEL, sk->sk_prot,
839 			 kern);
840 	if (!newsk) {
841 		pep_reject_conn(sk, skb, PN_PIPE_ERR_OVERLOAD, GFP_KERNEL);
842 		err = -ENOBUFS;
843 		goto drop;
844 	}
845 
846 	sock_init_data(NULL, newsk);
847 	newsk->sk_state = TCP_SYN_RECV;
848 	newsk->sk_backlog_rcv = pipe_do_rcv;
849 	newsk->sk_protocol = sk->sk_protocol;
850 	newsk->sk_destruct = pipe_destruct;
851 
852 	newpn = pep_sk(newsk);
853 	pn_skb_get_dst_sockaddr(skb, &dst);
854 	pn_skb_get_src_sockaddr(skb, &src);
855 	newpn->pn_sk.sobject = pn_sockaddr_get_object(&dst);
856 	newpn->pn_sk.dobject = pn_sockaddr_get_object(&src);
857 	newpn->pn_sk.resource = pn_sockaddr_get_resource(&dst);
858 	sock_hold(sk);
859 	newpn->listener = sk;
860 	skb_queue_head_init(&newpn->ctrlreq_queue);
861 	newpn->pipe_handle = pipe_handle;
862 	atomic_set(&newpn->tx_credits, 0);
863 	newpn->ifindex = 0;
864 	newpn->peer_type = peer_type;
865 	newpn->rx_credits = 0;
866 	newpn->rx_fc = newpn->tx_fc = PN_LEGACY_FLOW_CONTROL;
867 	newpn->init_enable = enabled;
868 	newpn->aligned = aligned;
869 
870 	err = pep_accept_conn(newsk, skb);
871 	if (err) {
872 		__sock_put(sk);
873 		sock_put(newsk);
874 		newsk = NULL;
875 		goto drop;
876 	}
877 	sk_add_node(newsk, &pn->hlist);
878 drop:
879 	release_sock(sk);
880 	kfree_skb(skb);
881 	*errp = err;
882 	return newsk;
883 }
884 
885 static int pep_sock_connect(struct sock *sk, struct sockaddr *addr, int len)
886 {
887 	struct pep_sock *pn = pep_sk(sk);
888 	int err;
889 	u8 data[4] = { 0 /* sub-blocks */, PAD, PAD, PAD };
890 
891 	if (pn->pipe_handle == PN_PIPE_INVALID_HANDLE)
892 		pn->pipe_handle = 1; /* anything but INVALID_HANDLE */
893 
894 	err = pipe_handler_request(sk, PNS_PEP_CONNECT_REQ,
895 				pn->init_enable, data, 4);
896 	if (err) {
897 		pn->pipe_handle = PN_PIPE_INVALID_HANDLE;
898 		return err;
899 	}
900 
901 	sk->sk_state = TCP_SYN_SENT;
902 
903 	return 0;
904 }
905 
906 static int pep_sock_enable(struct sock *sk, struct sockaddr *addr, int len)
907 {
908 	int err;
909 
910 	err = pipe_handler_request(sk, PNS_PEP_ENABLE_REQ, PAD,
911 				NULL, 0);
912 	if (err)
913 		return err;
914 
915 	sk->sk_state = TCP_SYN_SENT;
916 
917 	return 0;
918 }
919 
920 static unsigned int pep_first_packet_length(struct sock *sk)
921 {
922 	struct pep_sock *pn = pep_sk(sk);
923 	struct sk_buff_head *q;
924 	struct sk_buff *skb;
925 	unsigned int len = 0;
926 	bool found = false;
927 
928 	if (sock_flag(sk, SOCK_URGINLINE)) {
929 		q = &pn->ctrlreq_queue;
930 		spin_lock_bh(&q->lock);
931 		skb = skb_peek(q);
932 		if (skb) {
933 			len = skb->len;
934 			found = true;
935 		}
936 		spin_unlock_bh(&q->lock);
937 	}
938 
939 	if (likely(!found)) {
940 		q = &sk->sk_receive_queue;
941 		spin_lock_bh(&q->lock);
942 		skb = skb_peek(q);
943 		if (skb)
944 			len = skb->len;
945 		spin_unlock_bh(&q->lock);
946 	}
947 
948 	return len;
949 }
950 
951 static int pep_ioctl(struct sock *sk, int cmd, int *karg)
952 {
953 	struct pep_sock *pn = pep_sk(sk);
954 	int ret = -ENOIOCTLCMD;
955 
956 	switch (cmd) {
957 	case SIOCINQ:
958 		if (sk->sk_state == TCP_LISTEN) {
959 			ret = -EINVAL;
960 			break;
961 		}
962 
963 		*karg = pep_first_packet_length(sk);
964 		ret = 0;
965 		break;
966 
967 	case SIOCPNENABLEPIPE:
968 		lock_sock(sk);
969 		if (sk->sk_state == TCP_SYN_SENT)
970 			ret =  -EBUSY;
971 		else if (sk->sk_state == TCP_ESTABLISHED)
972 			ret = -EISCONN;
973 		else if (!pn->pn_sk.sobject)
974 			ret = -EADDRNOTAVAIL;
975 		else
976 			ret = pep_sock_enable(sk, NULL, 0);
977 		release_sock(sk);
978 		break;
979 	}
980 
981 	return ret;
982 }
983 
984 static int pep_init(struct sock *sk)
985 {
986 	struct pep_sock *pn = pep_sk(sk);
987 
988 	sk->sk_destruct = pipe_destruct;
989 	INIT_HLIST_HEAD(&pn->hlist);
990 	pn->listener = NULL;
991 	skb_queue_head_init(&pn->ctrlreq_queue);
992 	atomic_set(&pn->tx_credits, 0);
993 	pn->ifindex = 0;
994 	pn->peer_type = 0;
995 	pn->pipe_handle = PN_PIPE_INVALID_HANDLE;
996 	pn->rx_credits = 0;
997 	pn->rx_fc = pn->tx_fc = PN_LEGACY_FLOW_CONTROL;
998 	pn->init_enable = 1;
999 	pn->aligned = 0;
1000 	return 0;
1001 }
1002 
1003 static int pep_setsockopt(struct sock *sk, int level, int optname,
1004 			  sockptr_t optval, unsigned int optlen)
1005 {
1006 	struct pep_sock *pn = pep_sk(sk);
1007 	int val = 0, err = 0;
1008 
1009 	if (level != SOL_PNPIPE)
1010 		return -ENOPROTOOPT;
1011 	if (optlen >= sizeof(int)) {
1012 		if (copy_from_sockptr(&val, optval, sizeof(int)))
1013 			return -EFAULT;
1014 	}
1015 
1016 	lock_sock(sk);
1017 	switch (optname) {
1018 	case PNPIPE_ENCAP:
1019 		if (val && val != PNPIPE_ENCAP_IP) {
1020 			err = -EINVAL;
1021 			break;
1022 		}
1023 		if (!pn->ifindex == !val)
1024 			break; /* Nothing to do! */
1025 		if (!capable(CAP_NET_ADMIN)) {
1026 			err = -EPERM;
1027 			break;
1028 		}
1029 		if (val) {
1030 			release_sock(sk);
1031 			err = gprs_attach(sk);
1032 			if (err > 0) {
1033 				pn->ifindex = err;
1034 				err = 0;
1035 			}
1036 		} else {
1037 			pn->ifindex = 0;
1038 			release_sock(sk);
1039 			gprs_detach(sk);
1040 			err = 0;
1041 		}
1042 		goto out_norel;
1043 
1044 	case PNPIPE_HANDLE:
1045 		if ((sk->sk_state == TCP_CLOSE) &&
1046 			(val >= 0) && (val < PN_PIPE_INVALID_HANDLE))
1047 			pn->pipe_handle = val;
1048 		else
1049 			err = -EINVAL;
1050 		break;
1051 
1052 	case PNPIPE_INITSTATE:
1053 		pn->init_enable = !!val;
1054 		break;
1055 
1056 	default:
1057 		err = -ENOPROTOOPT;
1058 	}
1059 	release_sock(sk);
1060 
1061 out_norel:
1062 	return err;
1063 }
1064 
1065 static int pep_getsockopt(struct sock *sk, int level, int optname,
1066 				char __user *optval, int __user *optlen)
1067 {
1068 	struct pep_sock *pn = pep_sk(sk);
1069 	int len, val;
1070 
1071 	if (level != SOL_PNPIPE)
1072 		return -ENOPROTOOPT;
1073 	if (get_user(len, optlen))
1074 		return -EFAULT;
1075 
1076 	switch (optname) {
1077 	case PNPIPE_ENCAP:
1078 		val = pn->ifindex ? PNPIPE_ENCAP_IP : PNPIPE_ENCAP_NONE;
1079 		break;
1080 
1081 	case PNPIPE_IFINDEX:
1082 		val = pn->ifindex;
1083 		break;
1084 
1085 	case PNPIPE_HANDLE:
1086 		val = pn->pipe_handle;
1087 		if (val == PN_PIPE_INVALID_HANDLE)
1088 			return -EINVAL;
1089 		break;
1090 
1091 	case PNPIPE_INITSTATE:
1092 		val = pn->init_enable;
1093 		break;
1094 
1095 	default:
1096 		return -ENOPROTOOPT;
1097 	}
1098 
1099 	len = min_t(unsigned int, sizeof(int), len);
1100 	if (put_user(len, optlen))
1101 		return -EFAULT;
1102 	if (put_user(val, (int __user *) optval))
1103 		return -EFAULT;
1104 	return 0;
1105 }
1106 
1107 static int pipe_skb_send(struct sock *sk, struct sk_buff *skb)
1108 {
1109 	struct pep_sock *pn = pep_sk(sk);
1110 	struct pnpipehdr *ph;
1111 	int err;
1112 
1113 	if (pn_flow_safe(pn->tx_fc) &&
1114 	    !atomic_add_unless(&pn->tx_credits, -1, 0)) {
1115 		kfree_skb(skb);
1116 		return -ENOBUFS;
1117 	}
1118 
1119 	skb_push(skb, 3 + pn->aligned);
1120 	skb_reset_transport_header(skb);
1121 	ph = pnp_hdr(skb);
1122 	ph->utid = 0;
1123 	if (pn->aligned) {
1124 		ph->message_id = PNS_PIPE_ALIGNED_DATA;
1125 		ph->data0 = 0; /* padding */
1126 	} else
1127 		ph->message_id = PNS_PIPE_DATA;
1128 	ph->pipe_handle = pn->pipe_handle;
1129 	err = pn_skb_send(sk, skb, NULL);
1130 
1131 	if (err && pn_flow_safe(pn->tx_fc))
1132 		atomic_inc(&pn->tx_credits);
1133 	return err;
1134 
1135 }
1136 
1137 static int pep_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
1138 {
1139 	struct pep_sock *pn = pep_sk(sk);
1140 	struct sk_buff *skb;
1141 	long timeo;
1142 	int flags = msg->msg_flags;
1143 	int err, done;
1144 
1145 	if (len > USHRT_MAX)
1146 		return -EMSGSIZE;
1147 
1148 	if ((msg->msg_flags & ~(MSG_DONTWAIT|MSG_EOR|MSG_NOSIGNAL|
1149 				MSG_CMSG_COMPAT)) ||
1150 			!(msg->msg_flags & MSG_EOR))
1151 		return -EOPNOTSUPP;
1152 
1153 	skb = sock_alloc_send_skb(sk, MAX_PNPIPE_HEADER + len,
1154 					flags & MSG_DONTWAIT, &err);
1155 	if (!skb)
1156 		return err;
1157 
1158 	skb_reserve(skb, MAX_PHONET_HEADER + 3 + pn->aligned);
1159 	err = memcpy_from_msg(skb_put(skb, len), msg, len);
1160 	if (err < 0)
1161 		goto outfree;
1162 
1163 	lock_sock(sk);
1164 	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
1165 	if ((1 << sk->sk_state) & (TCPF_LISTEN|TCPF_CLOSE)) {
1166 		err = -ENOTCONN;
1167 		goto out;
1168 	}
1169 	if (sk->sk_state != TCP_ESTABLISHED) {
1170 		/* Wait until the pipe gets to enabled state */
1171 disabled:
1172 		err = sk_stream_wait_connect(sk, &timeo);
1173 		if (err)
1174 			goto out;
1175 
1176 		if (sk->sk_state == TCP_CLOSE_WAIT) {
1177 			err = -ECONNRESET;
1178 			goto out;
1179 		}
1180 	}
1181 	BUG_ON(sk->sk_state != TCP_ESTABLISHED);
1182 
1183 	/* Wait until flow control allows TX */
1184 	done = atomic_read(&pn->tx_credits);
1185 	while (!done) {
1186 		DEFINE_WAIT_FUNC(wait, woken_wake_function);
1187 
1188 		if (!timeo) {
1189 			err = -EAGAIN;
1190 			goto out;
1191 		}
1192 		if (signal_pending(current)) {
1193 			err = sock_intr_errno(timeo);
1194 			goto out;
1195 		}
1196 
1197 		add_wait_queue(sk_sleep(sk), &wait);
1198 		done = sk_wait_event(sk, &timeo, atomic_read(&pn->tx_credits), &wait);
1199 		remove_wait_queue(sk_sleep(sk), &wait);
1200 
1201 		if (sk->sk_state != TCP_ESTABLISHED)
1202 			goto disabled;
1203 	}
1204 
1205 	err = pipe_skb_send(sk, skb);
1206 	if (err >= 0)
1207 		err = len; /* success! */
1208 	skb = NULL;
1209 out:
1210 	release_sock(sk);
1211 outfree:
1212 	kfree_skb(skb);
1213 	return err;
1214 }
1215 
1216 int pep_writeable(struct sock *sk)
1217 {
1218 	struct pep_sock *pn = pep_sk(sk);
1219 
1220 	return atomic_read(&pn->tx_credits);
1221 }
1222 
1223 int pep_write(struct sock *sk, struct sk_buff *skb)
1224 {
1225 	struct sk_buff *rskb, *fs;
1226 	int flen = 0;
1227 
1228 	if (pep_sk(sk)->aligned)
1229 		return pipe_skb_send(sk, skb);
1230 
1231 	rskb = alloc_skb(MAX_PNPIPE_HEADER, GFP_ATOMIC);
1232 	if (!rskb) {
1233 		kfree_skb(skb);
1234 		return -ENOMEM;
1235 	}
1236 	skb_shinfo(rskb)->frag_list = skb;
1237 	rskb->len += skb->len;
1238 	rskb->data_len += rskb->len;
1239 	rskb->truesize += rskb->len;
1240 
1241 	/* Avoid nested fragments */
1242 	skb_walk_frags(skb, fs)
1243 		flen += fs->len;
1244 	skb->next = skb_shinfo(skb)->frag_list;
1245 	skb_frag_list_init(skb);
1246 	skb->len -= flen;
1247 	skb->data_len -= flen;
1248 	skb->truesize -= flen;
1249 
1250 	skb_reserve(rskb, MAX_PHONET_HEADER + 3);
1251 	return pipe_skb_send(sk, rskb);
1252 }
1253 
1254 struct sk_buff *pep_read(struct sock *sk)
1255 {
1256 	struct sk_buff *skb = skb_dequeue(&sk->sk_receive_queue);
1257 
1258 	if (sk->sk_state == TCP_ESTABLISHED)
1259 		pipe_grant_credits(sk, GFP_ATOMIC);
1260 	return skb;
1261 }
1262 
1263 static int pep_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
1264 		       int flags, int *addr_len)
1265 {
1266 	struct sk_buff *skb;
1267 	int err;
1268 
1269 	if (flags & ~(MSG_OOB|MSG_PEEK|MSG_TRUNC|MSG_DONTWAIT|MSG_WAITALL|
1270 			MSG_NOSIGNAL|MSG_CMSG_COMPAT))
1271 		return -EOPNOTSUPP;
1272 
1273 	if (unlikely(1 << sk->sk_state & (TCPF_LISTEN | TCPF_CLOSE)))
1274 		return -ENOTCONN;
1275 
1276 	if ((flags & MSG_OOB) || sock_flag(sk, SOCK_URGINLINE)) {
1277 		/* Dequeue and acknowledge control request */
1278 		struct pep_sock *pn = pep_sk(sk);
1279 
1280 		if (flags & MSG_PEEK)
1281 			return -EOPNOTSUPP;
1282 		skb = skb_dequeue(&pn->ctrlreq_queue);
1283 		if (skb) {
1284 			pep_ctrlreq_error(sk, skb, PN_PIPE_NO_ERROR,
1285 						GFP_KERNEL);
1286 			msg->msg_flags |= MSG_OOB;
1287 			goto copy;
1288 		}
1289 		if (flags & MSG_OOB)
1290 			return -EINVAL;
1291 	}
1292 
1293 	skb = skb_recv_datagram(sk, flags, &err);
1294 	lock_sock(sk);
1295 	if (skb == NULL) {
1296 		if (err == -ENOTCONN && sk->sk_state == TCP_CLOSE_WAIT)
1297 			err = -ECONNRESET;
1298 		release_sock(sk);
1299 		return err;
1300 	}
1301 
1302 	if (sk->sk_state == TCP_ESTABLISHED)
1303 		pipe_grant_credits(sk, GFP_KERNEL);
1304 	release_sock(sk);
1305 copy:
1306 	msg->msg_flags |= MSG_EOR;
1307 	if (skb->len > len)
1308 		msg->msg_flags |= MSG_TRUNC;
1309 	else
1310 		len = skb->len;
1311 
1312 	err = skb_copy_datagram_msg(skb, 0, msg, len);
1313 	if (!err)
1314 		err = (flags & MSG_TRUNC) ? skb->len : len;
1315 
1316 	skb_free_datagram(sk, skb);
1317 	return err;
1318 }
1319 
1320 static void pep_sock_unhash(struct sock *sk)
1321 {
1322 	struct pep_sock *pn = pep_sk(sk);
1323 	struct sock *skparent = NULL;
1324 
1325 	lock_sock(sk);
1326 
1327 	if (pn->listener != NULL) {
1328 		skparent = pn->listener;
1329 		pn->listener = NULL;
1330 		release_sock(sk);
1331 
1332 		pn = pep_sk(skparent);
1333 		lock_sock(skparent);
1334 		sk_del_node_init(sk);
1335 		sk = skparent;
1336 	}
1337 
1338 	/* Unhash a listening sock only when it is closed
1339 	 * and all of its active connected pipes are closed. */
1340 	if (hlist_empty(&pn->hlist))
1341 		pn_sock_unhash(&pn->pn_sk.sk);
1342 	release_sock(sk);
1343 
1344 	if (skparent)
1345 		sock_put(skparent);
1346 }
1347 
1348 static struct proto pep_proto = {
1349 	.close		= pep_sock_close,
1350 	.accept		= pep_sock_accept,
1351 	.connect	= pep_sock_connect,
1352 	.ioctl		= pep_ioctl,
1353 	.init		= pep_init,
1354 	.setsockopt	= pep_setsockopt,
1355 	.getsockopt	= pep_getsockopt,
1356 	.sendmsg	= pep_sendmsg,
1357 	.recvmsg	= pep_recvmsg,
1358 	.backlog_rcv	= pep_do_rcv,
1359 	.hash		= pn_sock_hash,
1360 	.unhash		= pep_sock_unhash,
1361 	.get_port	= pn_sock_get_port,
1362 	.obj_size	= sizeof(struct pep_sock),
1363 	.owner		= THIS_MODULE,
1364 	.name		= "PNPIPE",
1365 };
1366 
1367 static const struct phonet_protocol pep_pn_proto = {
1368 	.ops		= &phonet_stream_ops,
1369 	.prot		= &pep_proto,
1370 	.sock_type	= SOCK_SEQPACKET,
1371 };
1372 
1373 static int __init pep_register(void)
1374 {
1375 	return phonet_proto_register(PN_PROTO_PIPE, &pep_pn_proto);
1376 }
1377 
1378 static void __exit pep_unregister(void)
1379 {
1380 	phonet_proto_unregister(PN_PROTO_PIPE, &pep_pn_proto);
1381 }
1382 
1383 module_init(pep_register);
1384 module_exit(pep_unregister);
1385 MODULE_AUTHOR("Remi Denis-Courmont, Nokia");
1386 MODULE_DESCRIPTION("Phonet pipe protocol");
1387 MODULE_LICENSE("GPL");
1388 MODULE_ALIAS_NET_PF_PROTO(PF_PHONET, PN_PROTO_PIPE);
1389