xref: /openbmc/linux/net/phonet/pep.c (revision 4800cd83)
1 /*
2  * File: pep.c
3  *
4  * Phonet pipe protocol end point socket
5  *
6  * Copyright (C) 2008 Nokia Corporation.
7  *
8  * Author: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public License
12  * version 2 as published by the Free Software Foundation.
13  *
14  * This program is distributed in the hope that it will be useful, but
15  * WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17  * General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
22  * 02110-1301 USA
23  */
24 
25 #include <linux/kernel.h>
26 #include <linux/slab.h>
27 #include <linux/socket.h>
28 #include <net/sock.h>
29 #include <net/tcp_states.h>
30 #include <asm/ioctls.h>
31 
32 #include <linux/phonet.h>
33 #include <net/phonet/phonet.h>
34 #include <net/phonet/pep.h>
35 #include <net/phonet/gprs.h>
36 
37 /* sk_state values:
38  * TCP_CLOSE		sock not in use yet
39  * TCP_CLOSE_WAIT	disconnected pipe
40  * TCP_LISTEN		listening pipe endpoint
41  * TCP_SYN_RECV		connected pipe in disabled state
42  * TCP_ESTABLISHED	connected pipe in enabled state
43  *
44  * pep_sock locking:
45  *  - sk_state, ackq, hlist: sock lock needed
46  *  - listener: read only
47  *  - pipe_handle: read only
48  */
49 
50 #define CREDITS_MAX	10
51 #define CREDITS_THR	7
52 
53 static const struct sockaddr_pn pipe_srv = {
54 	.spn_family = AF_PHONET,
55 	.spn_resource = 0xD9, /* pipe service */
56 };
57 
58 #define pep_sb_size(s) (((s) + 5) & ~3) /* 2-bytes head, 32-bits aligned */
59 
60 /* Get the next TLV sub-block. */
61 static unsigned char *pep_get_sb(struct sk_buff *skb, u8 *ptype, u8 *plen,
62 					void *buf)
63 {
64 	void *data = NULL;
65 	struct {
66 		u8 sb_type;
67 		u8 sb_len;
68 	} *ph, h;
69 	int buflen = *plen;
70 
71 	ph = skb_header_pointer(skb, 0, 2, &h);
72 	if (ph == NULL || ph->sb_len < 2 || !pskb_may_pull(skb, ph->sb_len))
73 		return NULL;
74 	ph->sb_len -= 2;
75 	*ptype = ph->sb_type;
76 	*plen = ph->sb_len;
77 
78 	if (buflen > ph->sb_len)
79 		buflen = ph->sb_len;
80 	data = skb_header_pointer(skb, 2, buflen, buf);
81 	__skb_pull(skb, 2 + ph->sb_len);
82 	return data;
83 }
84 
85 static int pep_reply(struct sock *sk, struct sk_buff *oskb,
86 			u8 code, 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 
92 	skb = alloc_skb(MAX_PNPIPE_HEADER + len, priority);
93 	if (!skb)
94 		return -ENOMEM;
95 	skb_set_owner_w(skb, sk);
96 
97 	skb_reserve(skb, MAX_PNPIPE_HEADER);
98 	__skb_put(skb, len);
99 	skb_copy_to_linear_data(skb, data, len);
100 	__skb_push(skb, sizeof(*ph));
101 	skb_reset_transport_header(skb);
102 	ph = pnp_hdr(skb);
103 	ph->utid = oph->utid;
104 	ph->message_id = oph->message_id + 1; /* REQ -> RESP */
105 	ph->pipe_handle = oph->pipe_handle;
106 	ph->error_code = code;
107 
108 	return pn_skb_send(sk, skb, &pipe_srv);
109 }
110 
111 #define PAD 0x00
112 
113 #ifdef CONFIG_PHONET_PIPECTRLR
114 static u8 pipe_negotiate_fc(u8 *host_fc, u8 *remote_fc, int len)
115 {
116 	int i, j;
117 	u8 base_fc, final_fc;
118 
119 	for (i = 0; i < len; i++) {
120 		base_fc = host_fc[i];
121 		for (j = 0; j < len; j++) {
122 			if (remote_fc[j] == base_fc) {
123 				final_fc = base_fc;
124 				goto done;
125 			}
126 		}
127 	}
128 	return -EINVAL;
129 
130 done:
131 	return final_fc;
132 
133 }
134 
135 static int pipe_get_flow_info(struct sock *sk, struct sk_buff *skb,
136 		u8 *pref_rx_fc, u8 *req_tx_fc)
137 {
138 	struct pnpipehdr *hdr;
139 	u8 n_sb;
140 
141 	if (!pskb_may_pull(skb, sizeof(*hdr) + 4))
142 		return -EINVAL;
143 
144 	hdr = pnp_hdr(skb);
145 	n_sb = hdr->data[4];
146 
147 	__skb_pull(skb, sizeof(*hdr) + 4);
148 	while (n_sb > 0) {
149 		u8 type, buf[3], len = sizeof(buf);
150 		u8 *data = pep_get_sb(skb, &type, &len, buf);
151 
152 		if (data == NULL)
153 			return -EINVAL;
154 
155 		switch (type) {
156 		case PN_PIPE_SB_REQUIRED_FC_TX:
157 			if (len < 3 || (data[2] | data[3] | data[4]) > 3)
158 				break;
159 			req_tx_fc[0] = data[2];
160 			req_tx_fc[1] = data[3];
161 			req_tx_fc[2] = data[4];
162 			break;
163 
164 		case PN_PIPE_SB_PREFERRED_FC_RX:
165 			if (len < 3 || (data[2] | data[3] | data[4]) > 3)
166 				break;
167 			pref_rx_fc[0] = data[2];
168 			pref_rx_fc[1] = data[3];
169 			pref_rx_fc[2] = data[4];
170 			break;
171 
172 		}
173 		n_sb--;
174 	}
175 	return 0;
176 }
177 
178 static int pipe_handler_send_req(struct sock *sk, u8 utid,
179 		u8 msg_id, gfp_t priority)
180 {
181 	int len;
182 	struct pnpipehdr *ph;
183 	struct sk_buff *skb;
184 	struct pep_sock *pn = pep_sk(sk);
185 
186 	static const u8 data[4] = {
187 		PAD, PAD, PAD, PAD,
188 	};
189 
190 	switch (msg_id) {
191 	case PNS_PEP_CONNECT_REQ:
192 		len = sizeof(data);
193 		break;
194 
195 	case PNS_PEP_DISCONNECT_REQ:
196 	case PNS_PEP_ENABLE_REQ:
197 	case PNS_PEP_DISABLE_REQ:
198 		len = 0;
199 		break;
200 
201 	default:
202 		return -EINVAL;
203 	}
204 
205 	skb = alloc_skb(MAX_PNPIPE_HEADER + len, priority);
206 	if (!skb)
207 		return -ENOMEM;
208 	skb_set_owner_w(skb, sk);
209 
210 	skb_reserve(skb, MAX_PNPIPE_HEADER);
211 	if (len) {
212 		__skb_put(skb, len);
213 		skb_copy_to_linear_data(skb, data, len);
214 	}
215 	__skb_push(skb, sizeof(*ph));
216 	skb_reset_transport_header(skb);
217 	ph = pnp_hdr(skb);
218 	ph->utid = utid;
219 	ph->message_id = msg_id;
220 	ph->pipe_handle = pn->pipe_handle;
221 	ph->error_code = PN_PIPE_NO_ERROR;
222 
223 	return pn_skb_send(sk, skb, &pn->remote_pep);
224 }
225 
226 static int pipe_handler_send_created_ind(struct sock *sk,
227 		u8 utid, u8 msg_id)
228 {
229 	int err_code;
230 	struct pnpipehdr *ph;
231 	struct sk_buff *skb;
232 
233 	struct pep_sock *pn = pep_sk(sk);
234 	static u8 data[4] = {
235 		0x03, 0x04,
236 	};
237 	data[2] = pn->tx_fc;
238 	data[3] = pn->rx_fc;
239 
240 	/*
241 	 * actually, below is number of sub-blocks and not error code.
242 	 * Pipe_created_ind message format does not have any
243 	 * error code field. However, the Phonet stack will always send
244 	 * an error code as part of pnpipehdr. So, use that err_code to
245 	 * specify the number of sub-blocks.
246 	 */
247 	err_code = 0x01;
248 
249 	skb = alloc_skb(MAX_PNPIPE_HEADER + sizeof(data), GFP_ATOMIC);
250 	if (!skb)
251 		return -ENOMEM;
252 	skb_set_owner_w(skb, sk);
253 
254 	skb_reserve(skb, MAX_PNPIPE_HEADER);
255 	__skb_put(skb, sizeof(data));
256 	skb_copy_to_linear_data(skb, data, sizeof(data));
257 	__skb_push(skb, sizeof(*ph));
258 	skb_reset_transport_header(skb);
259 	ph = pnp_hdr(skb);
260 	ph->utid = utid;
261 	ph->message_id = msg_id;
262 	ph->pipe_handle = pn->pipe_handle;
263 	ph->error_code = err_code;
264 
265 	return pn_skb_send(sk, skb, &pn->remote_pep);
266 }
267 
268 static int pipe_handler_send_ind(struct sock *sk, u8 utid, u8 msg_id)
269 {
270 	int err_code;
271 	struct pnpipehdr *ph;
272 	struct sk_buff *skb;
273 	struct pep_sock *pn = pep_sk(sk);
274 
275 	/*
276 	 * actually, below is a filler.
277 	 * Pipe_enabled/disabled_ind message format does not have any
278 	 * error code field. However, the Phonet stack will always send
279 	 * an error code as part of pnpipehdr. So, use that err_code to
280 	 * specify the filler value.
281 	 */
282 	err_code = 0x0;
283 
284 	skb = alloc_skb(MAX_PNPIPE_HEADER, GFP_ATOMIC);
285 	if (!skb)
286 		return -ENOMEM;
287 	skb_set_owner_w(skb, sk);
288 
289 	skb_reserve(skb, MAX_PNPIPE_HEADER);
290 	__skb_push(skb, sizeof(*ph));
291 	skb_reset_transport_header(skb);
292 	ph = pnp_hdr(skb);
293 	ph->utid = utid;
294 	ph->message_id = msg_id;
295 	ph->pipe_handle = pn->pipe_handle;
296 	ph->error_code = err_code;
297 
298 	return pn_skb_send(sk, skb, &pn->remote_pep);
299 }
300 
301 static int pipe_handler_enable_pipe(struct sock *sk, int enable)
302 {
303 	int utid, req;
304 
305 	if (enable) {
306 		utid = PNS_PIPE_ENABLE_UTID;
307 		req = PNS_PEP_ENABLE_REQ;
308 	} else {
309 		utid = PNS_PIPE_DISABLE_UTID;
310 		req = PNS_PEP_DISABLE_REQ;
311 	}
312 	return pipe_handler_send_req(sk, utid, req, GFP_ATOMIC);
313 }
314 #endif
315 
316 static int pep_accept_conn(struct sock *sk, struct sk_buff *skb)
317 {
318 	static const u8 data[20] = {
319 		PAD, PAD, PAD, 2 /* sub-blocks */,
320 		PN_PIPE_SB_REQUIRED_FC_TX, pep_sb_size(5), 3, PAD,
321 			PN_MULTI_CREDIT_FLOW_CONTROL,
322 			PN_ONE_CREDIT_FLOW_CONTROL,
323 			PN_LEGACY_FLOW_CONTROL,
324 			PAD,
325 		PN_PIPE_SB_PREFERRED_FC_RX, pep_sb_size(5), 3, PAD,
326 			PN_MULTI_CREDIT_FLOW_CONTROL,
327 			PN_ONE_CREDIT_FLOW_CONTROL,
328 			PN_LEGACY_FLOW_CONTROL,
329 			PAD,
330 	};
331 
332 	might_sleep();
333 	return pep_reply(sk, skb, PN_PIPE_NO_ERROR, data, sizeof(data),
334 				GFP_KERNEL);
335 }
336 
337 static int pep_reject_conn(struct sock *sk, struct sk_buff *skb, u8 code)
338 {
339 	static const u8 data[4] = { PAD, PAD, PAD, 0 /* sub-blocks */ };
340 	WARN_ON(code == PN_PIPE_NO_ERROR);
341 	return pep_reply(sk, skb, code, data, sizeof(data), GFP_ATOMIC);
342 }
343 
344 /* Control requests are not sent by the pipe service and have a specific
345  * message format. */
346 static int pep_ctrlreq_error(struct sock *sk, struct sk_buff *oskb, u8 code,
347 				gfp_t priority)
348 {
349 	const struct pnpipehdr *oph = pnp_hdr(oskb);
350 	struct sk_buff *skb;
351 	struct pnpipehdr *ph;
352 	struct sockaddr_pn dst;
353 
354 	skb = alloc_skb(MAX_PNPIPE_HEADER + 4, priority);
355 	if (!skb)
356 		return -ENOMEM;
357 	skb_set_owner_w(skb, sk);
358 
359 	skb_reserve(skb, MAX_PHONET_HEADER);
360 	ph = (struct pnpipehdr *)skb_put(skb, sizeof(*ph) + 4);
361 
362 	ph->utid = oph->utid;
363 	ph->message_id = PNS_PEP_CTRL_RESP;
364 	ph->pipe_handle = oph->pipe_handle;
365 	ph->data[0] = oph->data[1]; /* CTRL id */
366 	ph->data[1] = oph->data[0]; /* PEP type */
367 	ph->data[2] = code; /* error code, at an usual offset */
368 	ph->data[3] = PAD;
369 	ph->data[4] = PAD;
370 
371 	pn_skb_get_src_sockaddr(oskb, &dst);
372 	return pn_skb_send(sk, skb, &dst);
373 }
374 
375 static int pipe_snd_status(struct sock *sk, u8 type, u8 status, gfp_t priority)
376 {
377 	struct pep_sock *pn = pep_sk(sk);
378 	struct pnpipehdr *ph;
379 	struct sk_buff *skb;
380 
381 	skb = alloc_skb(MAX_PNPIPE_HEADER + 4, priority);
382 	if (!skb)
383 		return -ENOMEM;
384 	skb_set_owner_w(skb, sk);
385 
386 	skb_reserve(skb, MAX_PNPIPE_HEADER + 4);
387 	__skb_push(skb, sizeof(*ph) + 4);
388 	skb_reset_transport_header(skb);
389 	ph = pnp_hdr(skb);
390 	ph->utid = 0;
391 	ph->message_id = PNS_PEP_STATUS_IND;
392 	ph->pipe_handle = pn->pipe_handle;
393 	ph->pep_type = PN_PEP_TYPE_COMMON;
394 	ph->data[1] = type;
395 	ph->data[2] = PAD;
396 	ph->data[3] = PAD;
397 	ph->data[4] = status;
398 
399 #ifdef CONFIG_PHONET_PIPECTRLR
400 	return pn_skb_send(sk, skb, &pn->remote_pep);
401 #else
402 	return pn_skb_send(sk, skb, &pipe_srv);
403 #endif
404 }
405 
406 /* Send our RX flow control information to the sender.
407  * Socket must be locked. */
408 static void pipe_grant_credits(struct sock *sk)
409 {
410 	struct pep_sock *pn = pep_sk(sk);
411 
412 	BUG_ON(sk->sk_state != TCP_ESTABLISHED);
413 
414 	switch (pn->rx_fc) {
415 	case PN_LEGACY_FLOW_CONTROL: /* TODO */
416 		break;
417 	case PN_ONE_CREDIT_FLOW_CONTROL:
418 		pipe_snd_status(sk, PN_PEP_IND_FLOW_CONTROL,
419 				PEP_IND_READY, GFP_ATOMIC);
420 		pn->rx_credits = 1;
421 		break;
422 	case PN_MULTI_CREDIT_FLOW_CONTROL:
423 		if ((pn->rx_credits + CREDITS_THR) > CREDITS_MAX)
424 			break;
425 		if (pipe_snd_status(sk, PN_PEP_IND_ID_MCFC_GRANT_CREDITS,
426 					CREDITS_MAX - pn->rx_credits,
427 					GFP_ATOMIC) == 0)
428 			pn->rx_credits = CREDITS_MAX;
429 		break;
430 	}
431 }
432 
433 static int pipe_rcv_status(struct sock *sk, struct sk_buff *skb)
434 {
435 	struct pep_sock *pn = pep_sk(sk);
436 	struct pnpipehdr *hdr;
437 	int wake = 0;
438 
439 	if (!pskb_may_pull(skb, sizeof(*hdr) + 4))
440 		return -EINVAL;
441 
442 	hdr = pnp_hdr(skb);
443 	if (hdr->data[0] != PN_PEP_TYPE_COMMON) {
444 		LIMIT_NETDEBUG(KERN_DEBUG"Phonet unknown PEP type: %u\n",
445 				(unsigned)hdr->data[0]);
446 		return -EOPNOTSUPP;
447 	}
448 
449 	switch (hdr->data[1]) {
450 	case PN_PEP_IND_FLOW_CONTROL:
451 		switch (pn->tx_fc) {
452 		case PN_LEGACY_FLOW_CONTROL:
453 			switch (hdr->data[4]) {
454 			case PEP_IND_BUSY:
455 				atomic_set(&pn->tx_credits, 0);
456 				break;
457 			case PEP_IND_READY:
458 				atomic_set(&pn->tx_credits, wake = 1);
459 				break;
460 			}
461 			break;
462 		case PN_ONE_CREDIT_FLOW_CONTROL:
463 			if (hdr->data[4] == PEP_IND_READY)
464 				atomic_set(&pn->tx_credits, wake = 1);
465 			break;
466 		}
467 		break;
468 
469 	case PN_PEP_IND_ID_MCFC_GRANT_CREDITS:
470 		if (pn->tx_fc != PN_MULTI_CREDIT_FLOW_CONTROL)
471 			break;
472 		atomic_add(wake = hdr->data[4], &pn->tx_credits);
473 		break;
474 
475 	default:
476 		LIMIT_NETDEBUG(KERN_DEBUG"Phonet unknown PEP indication: %u\n",
477 				(unsigned)hdr->data[1]);
478 		return -EOPNOTSUPP;
479 	}
480 	if (wake)
481 		sk->sk_write_space(sk);
482 	return 0;
483 }
484 
485 static int pipe_rcv_created(struct sock *sk, struct sk_buff *skb)
486 {
487 	struct pep_sock *pn = pep_sk(sk);
488 	struct pnpipehdr *hdr = pnp_hdr(skb);
489 	u8 n_sb = hdr->data[0];
490 
491 	pn->rx_fc = pn->tx_fc = PN_LEGACY_FLOW_CONTROL;
492 	__skb_pull(skb, sizeof(*hdr));
493 	while (n_sb > 0) {
494 		u8 type, buf[2], len = sizeof(buf);
495 		u8 *data = pep_get_sb(skb, &type, &len, buf);
496 
497 		if (data == NULL)
498 			return -EINVAL;
499 		switch (type) {
500 		case PN_PIPE_SB_NEGOTIATED_FC:
501 			if (len < 2 || (data[0] | data[1]) > 3)
502 				break;
503 			pn->tx_fc = data[0] & 3;
504 			pn->rx_fc = data[1] & 3;
505 			break;
506 		}
507 		n_sb--;
508 	}
509 	return 0;
510 }
511 
512 /* Queue an skb to a connected sock.
513  * Socket lock must be held. */
514 static int pipe_do_rcv(struct sock *sk, struct sk_buff *skb)
515 {
516 	struct pep_sock *pn = pep_sk(sk);
517 	struct pnpipehdr *hdr = pnp_hdr(skb);
518 	struct sk_buff_head *queue;
519 	int err = 0;
520 
521 	BUG_ON(sk->sk_state == TCP_CLOSE_WAIT);
522 
523 	switch (hdr->message_id) {
524 	case PNS_PEP_CONNECT_REQ:
525 		pep_reject_conn(sk, skb, PN_PIPE_ERR_PEP_IN_USE);
526 		break;
527 
528 	case PNS_PEP_DISCONNECT_REQ:
529 		pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC);
530 		sk->sk_state = TCP_CLOSE_WAIT;
531 		if (!sock_flag(sk, SOCK_DEAD))
532 			sk->sk_state_change(sk);
533 		break;
534 
535 #ifdef CONFIG_PHONET_PIPECTRLR
536 	case PNS_PEP_DISCONNECT_RESP:
537 		pn->pipe_state = PIPE_IDLE;
538 		sk->sk_state = TCP_CLOSE;
539 		break;
540 #endif
541 
542 	case PNS_PEP_ENABLE_REQ:
543 		/* Wait for PNS_PIPE_(ENABLED|REDIRECTED)_IND */
544 		pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC);
545 		break;
546 
547 #ifdef CONFIG_PHONET_PIPECTRLR
548 	case PNS_PEP_ENABLE_RESP:
549 		pn->pipe_state = PIPE_ENABLED;
550 		pipe_handler_send_ind(sk, PNS_PIPE_ENABLED_IND_UTID,
551 				PNS_PIPE_ENABLED_IND);
552 
553 		if (!pn_flow_safe(pn->tx_fc)) {
554 			atomic_set(&pn->tx_credits, 1);
555 			sk->sk_write_space(sk);
556 		}
557 		if (sk->sk_state == TCP_ESTABLISHED)
558 			break; /* Nothing to do */
559 		sk->sk_state = TCP_ESTABLISHED;
560 		pipe_grant_credits(sk);
561 		break;
562 #endif
563 
564 	case PNS_PEP_RESET_REQ:
565 		switch (hdr->state_after_reset) {
566 		case PN_PIPE_DISABLE:
567 			pn->init_enable = 0;
568 			break;
569 		case PN_PIPE_ENABLE:
570 			pn->init_enable = 1;
571 			break;
572 		default: /* not allowed to send an error here!? */
573 			err = -EINVAL;
574 			goto out;
575 		}
576 		/* fall through */
577 	case PNS_PEP_DISABLE_REQ:
578 		atomic_set(&pn->tx_credits, 0);
579 		pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC);
580 		break;
581 
582 #ifdef CONFIG_PHONET_PIPECTRLR
583 	case PNS_PEP_DISABLE_RESP:
584 		pn->pipe_state = PIPE_DISABLED;
585 		atomic_set(&pn->tx_credits, 0);
586 		pipe_handler_send_ind(sk, PNS_PIPE_DISABLED_IND_UTID,
587 				PNS_PIPE_DISABLED_IND);
588 		sk->sk_state = TCP_SYN_RECV;
589 		pn->rx_credits = 0;
590 		break;
591 #endif
592 
593 	case PNS_PEP_CTRL_REQ:
594 		if (skb_queue_len(&pn->ctrlreq_queue) >= PNPIPE_CTRLREQ_MAX) {
595 			atomic_inc(&sk->sk_drops);
596 			break;
597 		}
598 		__skb_pull(skb, 4);
599 		queue = &pn->ctrlreq_queue;
600 		goto queue;
601 
602 	case PNS_PIPE_ALIGNED_DATA:
603 		__skb_pull(skb, 1);
604 		/* fall through */
605 	case PNS_PIPE_DATA:
606 		__skb_pull(skb, 3); /* Pipe data header */
607 		if (!pn_flow_safe(pn->rx_fc)) {
608 			err = sock_queue_rcv_skb(sk, skb);
609 			if (!err)
610 				return 0;
611 			break;
612 		}
613 
614 		if (pn->rx_credits == 0) {
615 			atomic_inc(&sk->sk_drops);
616 			err = -ENOBUFS;
617 			break;
618 		}
619 		pn->rx_credits--;
620 		queue = &sk->sk_receive_queue;
621 		goto queue;
622 
623 	case PNS_PEP_STATUS_IND:
624 		pipe_rcv_status(sk, skb);
625 		break;
626 
627 	case PNS_PIPE_REDIRECTED_IND:
628 		err = pipe_rcv_created(sk, skb);
629 		break;
630 
631 	case PNS_PIPE_CREATED_IND:
632 		err = pipe_rcv_created(sk, skb);
633 		if (err)
634 			break;
635 		/* fall through */
636 	case PNS_PIPE_RESET_IND:
637 		if (!pn->init_enable)
638 			break;
639 		/* fall through */
640 	case PNS_PIPE_ENABLED_IND:
641 		if (!pn_flow_safe(pn->tx_fc)) {
642 			atomic_set(&pn->tx_credits, 1);
643 			sk->sk_write_space(sk);
644 		}
645 		if (sk->sk_state == TCP_ESTABLISHED)
646 			break; /* Nothing to do */
647 		sk->sk_state = TCP_ESTABLISHED;
648 		pipe_grant_credits(sk);
649 		break;
650 
651 	case PNS_PIPE_DISABLED_IND:
652 		sk->sk_state = TCP_SYN_RECV;
653 		pn->rx_credits = 0;
654 		break;
655 
656 	default:
657 		LIMIT_NETDEBUG(KERN_DEBUG"Phonet unknown PEP message: %u\n",
658 				hdr->message_id);
659 		err = -EINVAL;
660 	}
661 out:
662 	kfree_skb(skb);
663 	return err;
664 
665 queue:
666 	skb->dev = NULL;
667 	skb_set_owner_r(skb, sk);
668 	err = skb->len;
669 	skb_queue_tail(queue, skb);
670 	if (!sock_flag(sk, SOCK_DEAD))
671 		sk->sk_data_ready(sk, err);
672 	return 0;
673 }
674 
675 /* Destroy connected sock. */
676 static void pipe_destruct(struct sock *sk)
677 {
678 	struct pep_sock *pn = pep_sk(sk);
679 
680 	skb_queue_purge(&sk->sk_receive_queue);
681 	skb_queue_purge(&pn->ctrlreq_queue);
682 }
683 
684 #ifdef CONFIG_PHONET_PIPECTRLR
685 static int pep_connresp_rcv(struct sock *sk, struct sk_buff *skb)
686 {
687 	struct pep_sock *pn = pep_sk(sk);
688 	u8 host_pref_rx_fc[3] = {3, 2, 1}, host_req_tx_fc[3] = {3, 2, 1};
689 	u8 remote_pref_rx_fc[3], remote_req_tx_fc[3];
690 	u8 negotiated_rx_fc, negotiated_tx_fc;
691 	int ret;
692 
693 	pipe_get_flow_info(sk, skb, remote_pref_rx_fc,
694 			remote_req_tx_fc);
695 	negotiated_tx_fc = pipe_negotiate_fc(remote_req_tx_fc,
696 			host_pref_rx_fc,
697 			sizeof(host_pref_rx_fc));
698 	negotiated_rx_fc = pipe_negotiate_fc(host_req_tx_fc,
699 			remote_pref_rx_fc,
700 			sizeof(host_pref_rx_fc));
701 
702 	pn->pipe_state = PIPE_DISABLED;
703 	sk->sk_state = TCP_SYN_RECV;
704 	sk->sk_backlog_rcv = pipe_do_rcv;
705 	sk->sk_destruct = pipe_destruct;
706 	pn->rx_credits = 0;
707 	pn->rx_fc = negotiated_rx_fc;
708 	pn->tx_fc = negotiated_tx_fc;
709 	sk->sk_state_change(sk);
710 
711 	ret = pipe_handler_send_created_ind(sk,
712 			PNS_PIPE_CREATED_IND_UTID,
713 			PNS_PIPE_CREATED_IND
714 			);
715 
716 	return ret;
717 }
718 #endif
719 
720 static int pep_connreq_rcv(struct sock *sk, struct sk_buff *skb)
721 {
722 	struct sock *newsk;
723 	struct pep_sock *newpn, *pn = pep_sk(sk);
724 	struct pnpipehdr *hdr;
725 	struct sockaddr_pn dst;
726 	u16 peer_type;
727 	u8 pipe_handle, enabled, n_sb;
728 	u8 aligned = 0;
729 
730 	if (!pskb_pull(skb, sizeof(*hdr) + 4))
731 		return -EINVAL;
732 
733 	hdr = pnp_hdr(skb);
734 	pipe_handle = hdr->pipe_handle;
735 	switch (hdr->state_after_connect) {
736 	case PN_PIPE_DISABLE:
737 		enabled = 0;
738 		break;
739 	case PN_PIPE_ENABLE:
740 		enabled = 1;
741 		break;
742 	default:
743 		pep_reject_conn(sk, skb, PN_PIPE_ERR_INVALID_PARAM);
744 		return -EINVAL;
745 	}
746 	peer_type = hdr->other_pep_type << 8;
747 
748 	if (unlikely(sk->sk_state != TCP_LISTEN) || sk_acceptq_is_full(sk)) {
749 		pep_reject_conn(sk, skb, PN_PIPE_ERR_PEP_IN_USE);
750 		return -ENOBUFS;
751 	}
752 
753 	/* Parse sub-blocks (options) */
754 	n_sb = hdr->data[4];
755 	while (n_sb > 0) {
756 		u8 type, buf[1], len = sizeof(buf);
757 		const u8 *data = pep_get_sb(skb, &type, &len, buf);
758 
759 		if (data == NULL)
760 			return -EINVAL;
761 		switch (type) {
762 		case PN_PIPE_SB_CONNECT_REQ_PEP_SUB_TYPE:
763 			if (len < 1)
764 				return -EINVAL;
765 			peer_type = (peer_type & 0xff00) | data[0];
766 			break;
767 		case PN_PIPE_SB_ALIGNED_DATA:
768 			aligned = data[0] != 0;
769 			break;
770 		}
771 		n_sb--;
772 	}
773 
774 	skb = skb_clone(skb, GFP_ATOMIC);
775 	if (!skb)
776 		return -ENOMEM;
777 
778 	/* Create a new to-be-accepted sock */
779 	newsk = sk_alloc(sock_net(sk), PF_PHONET, GFP_ATOMIC, sk->sk_prot);
780 	if (!newsk) {
781 		kfree_skb(skb);
782 		return -ENOMEM;
783 	}
784 	sock_init_data(NULL, newsk);
785 	newsk->sk_state = TCP_SYN_RECV;
786 	newsk->sk_backlog_rcv = pipe_do_rcv;
787 	newsk->sk_protocol = sk->sk_protocol;
788 	newsk->sk_destruct = pipe_destruct;
789 
790 	newpn = pep_sk(newsk);
791 	pn_skb_get_dst_sockaddr(skb, &dst);
792 	newpn->pn_sk.sobject = pn_sockaddr_get_object(&dst);
793 	newpn->pn_sk.resource = pn->pn_sk.resource;
794 	skb_queue_head_init(&newpn->ctrlreq_queue);
795 	newpn->pipe_handle = pipe_handle;
796 	atomic_set(&newpn->tx_credits, 0);
797 	newpn->peer_type = peer_type;
798 	newpn->rx_credits = 0;
799 	newpn->rx_fc = newpn->tx_fc = PN_LEGACY_FLOW_CONTROL;
800 	newpn->init_enable = enabled;
801 	newpn->aligned = aligned;
802 
803 	BUG_ON(!skb_queue_empty(&newsk->sk_receive_queue));
804 	skb_queue_head(&newsk->sk_receive_queue, skb);
805 	if (!sock_flag(sk, SOCK_DEAD))
806 		sk->sk_data_ready(sk, 0);
807 
808 	sk_acceptq_added(sk);
809 	sk_add_node(newsk, &pn->ackq);
810 	return 0;
811 }
812 
813 /* Listening sock must be locked */
814 static struct sock *pep_find_pipe(const struct hlist_head *hlist,
815 					const struct sockaddr_pn *dst,
816 					u8 pipe_handle)
817 {
818 	struct hlist_node *node;
819 	struct sock *sknode;
820 	u16 dobj = pn_sockaddr_get_object(dst);
821 
822 	sk_for_each(sknode, node, hlist) {
823 		struct pep_sock *pnnode = pep_sk(sknode);
824 
825 		/* Ports match, but addresses might not: */
826 		if (pnnode->pn_sk.sobject != dobj)
827 			continue;
828 		if (pnnode->pipe_handle != pipe_handle)
829 			continue;
830 		if (sknode->sk_state == TCP_CLOSE_WAIT)
831 			continue;
832 
833 		sock_hold(sknode);
834 		return sknode;
835 	}
836 	return NULL;
837 }
838 
839 /*
840  * Deliver an skb to a listening sock.
841  * Socket lock must be held.
842  * We then queue the skb to the right connected sock (if any).
843  */
844 static int pep_do_rcv(struct sock *sk, struct sk_buff *skb)
845 {
846 	struct pep_sock *pn = pep_sk(sk);
847 	struct sock *sknode;
848 	struct pnpipehdr *hdr;
849 	struct sockaddr_pn dst;
850 	int err = NET_RX_SUCCESS;
851 	u8 pipe_handle;
852 
853 	if (!pskb_may_pull(skb, sizeof(*hdr)))
854 		goto drop;
855 
856 	hdr = pnp_hdr(skb);
857 	pipe_handle = hdr->pipe_handle;
858 	if (pipe_handle == PN_PIPE_INVALID_HANDLE)
859 		goto drop;
860 
861 	pn_skb_get_dst_sockaddr(skb, &dst);
862 
863 	/* Look for an existing pipe handle */
864 	sknode = pep_find_pipe(&pn->hlist, &dst, pipe_handle);
865 	if (sknode)
866 		return sk_receive_skb(sknode, skb, 1);
867 
868 	/* Look for a pipe handle pending accept */
869 	sknode = pep_find_pipe(&pn->ackq, &dst, pipe_handle);
870 	if (sknode) {
871 		sock_put(sknode);
872 		if (net_ratelimit())
873 			printk(KERN_WARNING"Phonet unconnected PEP ignored");
874 		err = NET_RX_DROP;
875 		goto drop;
876 	}
877 
878 	switch (hdr->message_id) {
879 	case PNS_PEP_CONNECT_REQ:
880 		err = pep_connreq_rcv(sk, skb);
881 		break;
882 
883 #ifdef CONFIG_PHONET_PIPECTRLR
884 	case PNS_PEP_CONNECT_RESP:
885 		err = pep_connresp_rcv(sk, skb);
886 		break;
887 #endif
888 
889 	case PNS_PEP_DISCONNECT_REQ:
890 		pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC);
891 		break;
892 
893 	case PNS_PEP_CTRL_REQ:
894 		pep_ctrlreq_error(sk, skb, PN_PIPE_INVALID_HANDLE, GFP_ATOMIC);
895 		break;
896 
897 	case PNS_PEP_RESET_REQ:
898 	case PNS_PEP_ENABLE_REQ:
899 	case PNS_PEP_DISABLE_REQ:
900 		/* invalid handle is not even allowed here! */
901 	default:
902 		err = NET_RX_DROP;
903 	}
904 drop:
905 	kfree_skb(skb);
906 	return err;
907 }
908 
909 static int pipe_do_remove(struct sock *sk)
910 {
911 	struct pep_sock *pn = pep_sk(sk);
912 	struct pnpipehdr *ph;
913 	struct sk_buff *skb;
914 
915 	skb = alloc_skb(MAX_PNPIPE_HEADER, GFP_KERNEL);
916 	if (!skb)
917 		return -ENOMEM;
918 
919 	skb_reserve(skb, MAX_PNPIPE_HEADER);
920 	__skb_push(skb, sizeof(*ph));
921 	skb_reset_transport_header(skb);
922 	ph = pnp_hdr(skb);
923 	ph->utid = 0;
924 	ph->message_id = PNS_PIPE_REMOVE_REQ;
925 	ph->pipe_handle = pn->pipe_handle;
926 	ph->data[0] = PAD;
927 
928 	return pn_skb_send(sk, skb, &pipe_srv);
929 }
930 
931 /* associated socket ceases to exist */
932 static void pep_sock_close(struct sock *sk, long timeout)
933 {
934 	struct pep_sock *pn = pep_sk(sk);
935 	int ifindex = 0;
936 
937 	sock_hold(sk); /* keep a reference after sk_common_release() */
938 	sk_common_release(sk);
939 
940 	lock_sock(sk);
941 	if (sk->sk_state == TCP_LISTEN) {
942 		/* Destroy the listen queue */
943 		struct sock *sknode;
944 		struct hlist_node *p, *n;
945 
946 		sk_for_each_safe(sknode, p, n, &pn->ackq)
947 			sk_del_node_init(sknode);
948 		sk->sk_state = TCP_CLOSE;
949 	} else if ((1 << sk->sk_state) & (TCPF_SYN_RECV|TCPF_ESTABLISHED))
950 		/* Forcefully remove dangling Phonet pipe */
951 		pipe_do_remove(sk);
952 
953 #ifdef CONFIG_PHONET_PIPECTRLR
954 	if (pn->pipe_state != PIPE_IDLE) {
955 		/* send pep disconnect request */
956 		pipe_handler_send_req(sk,
957 				PNS_PEP_DISCONNECT_UTID, PNS_PEP_DISCONNECT_REQ,
958 				GFP_KERNEL);
959 
960 		pn->pipe_state = PIPE_IDLE;
961 		sk->sk_state = TCP_CLOSE;
962 	}
963 #endif
964 
965 	ifindex = pn->ifindex;
966 	pn->ifindex = 0;
967 	release_sock(sk);
968 
969 	if (ifindex)
970 		gprs_detach(sk);
971 	sock_put(sk);
972 }
973 
974 static int pep_wait_connreq(struct sock *sk, int noblock)
975 {
976 	struct task_struct *tsk = current;
977 	struct pep_sock *pn = pep_sk(sk);
978 	long timeo = sock_rcvtimeo(sk, noblock);
979 
980 	for (;;) {
981 		DEFINE_WAIT(wait);
982 
983 		if (sk->sk_state != TCP_LISTEN)
984 			return -EINVAL;
985 		if (!hlist_empty(&pn->ackq))
986 			break;
987 		if (!timeo)
988 			return -EWOULDBLOCK;
989 		if (signal_pending(tsk))
990 			return sock_intr_errno(timeo);
991 
992 		prepare_to_wait_exclusive(sk_sleep(sk), &wait,
993 						TASK_INTERRUPTIBLE);
994 		release_sock(sk);
995 		timeo = schedule_timeout(timeo);
996 		lock_sock(sk);
997 		finish_wait(sk_sleep(sk), &wait);
998 	}
999 
1000 	return 0;
1001 }
1002 
1003 static struct sock *pep_sock_accept(struct sock *sk, int flags, int *errp)
1004 {
1005 	struct pep_sock *pn = pep_sk(sk);
1006 	struct sock *newsk = NULL;
1007 	struct sk_buff *oskb;
1008 	int err;
1009 
1010 	lock_sock(sk);
1011 	err = pep_wait_connreq(sk, flags & O_NONBLOCK);
1012 	if (err)
1013 		goto out;
1014 
1015 	newsk = __sk_head(&pn->ackq);
1016 
1017 	oskb = skb_dequeue(&newsk->sk_receive_queue);
1018 	err = pep_accept_conn(newsk, oskb);
1019 	if (err) {
1020 		skb_queue_head(&newsk->sk_receive_queue, oskb);
1021 		newsk = NULL;
1022 		goto out;
1023 	}
1024 	kfree_skb(oskb);
1025 
1026 	sock_hold(sk);
1027 	pep_sk(newsk)->listener = sk;
1028 
1029 	sock_hold(newsk);
1030 	sk_del_node_init(newsk);
1031 	sk_acceptq_removed(sk);
1032 	sk_add_node(newsk, &pn->hlist);
1033 	__sock_put(newsk);
1034 
1035 out:
1036 	release_sock(sk);
1037 	*errp = err;
1038 	return newsk;
1039 }
1040 
1041 #ifdef CONFIG_PHONET_PIPECTRLR
1042 static int pep_sock_connect(struct sock *sk, struct sockaddr *addr, int len)
1043 {
1044 	struct pep_sock *pn = pep_sk(sk);
1045 	struct sockaddr_pn *spn =  (struct sockaddr_pn *)addr;
1046 
1047 	memcpy(&pn->remote_pep, spn, sizeof(struct sockaddr_pn));
1048 
1049 	return pipe_handler_send_req(sk,
1050 			PNS_PEP_CONNECT_UTID, PNS_PEP_CONNECT_REQ,
1051 			GFP_ATOMIC);
1052 }
1053 #endif
1054 
1055 static int pep_ioctl(struct sock *sk, int cmd, unsigned long arg)
1056 {
1057 	struct pep_sock *pn = pep_sk(sk);
1058 	int answ;
1059 
1060 	switch (cmd) {
1061 	case SIOCINQ:
1062 		if (sk->sk_state == TCP_LISTEN)
1063 			return -EINVAL;
1064 
1065 		lock_sock(sk);
1066 		if (sock_flag(sk, SOCK_URGINLINE) &&
1067 		    !skb_queue_empty(&pn->ctrlreq_queue))
1068 			answ = skb_peek(&pn->ctrlreq_queue)->len;
1069 		else if (!skb_queue_empty(&sk->sk_receive_queue))
1070 			answ = skb_peek(&sk->sk_receive_queue)->len;
1071 		else
1072 			answ = 0;
1073 		release_sock(sk);
1074 		return put_user(answ, (int __user *)arg);
1075 	}
1076 
1077 	return -ENOIOCTLCMD;
1078 }
1079 
1080 static int pep_init(struct sock *sk)
1081 {
1082 	struct pep_sock *pn = pep_sk(sk);
1083 
1084 	INIT_HLIST_HEAD(&pn->ackq);
1085 	INIT_HLIST_HEAD(&pn->hlist);
1086 	skb_queue_head_init(&pn->ctrlreq_queue);
1087 	pn->pipe_handle = PN_PIPE_INVALID_HANDLE;
1088 	return 0;
1089 }
1090 
1091 static int pep_setsockopt(struct sock *sk, int level, int optname,
1092 				char __user *optval, unsigned int optlen)
1093 {
1094 	struct pep_sock *pn = pep_sk(sk);
1095 	int val = 0, err = 0;
1096 
1097 	if (level != SOL_PNPIPE)
1098 		return -ENOPROTOOPT;
1099 	if (optlen >= sizeof(int)) {
1100 		if (get_user(val, (int __user *) optval))
1101 			return -EFAULT;
1102 	}
1103 
1104 	lock_sock(sk);
1105 	switch (optname) {
1106 #ifdef CONFIG_PHONET_PIPECTRLR
1107 	case PNPIPE_PIPE_HANDLE:
1108 		if (val) {
1109 			if (pn->pipe_state > PIPE_IDLE) {
1110 				err = -EFAULT;
1111 				break;
1112 			}
1113 			pn->pipe_handle = val;
1114 			break;
1115 		}
1116 #endif
1117 
1118 	case PNPIPE_ENCAP:
1119 		if (val && val != PNPIPE_ENCAP_IP) {
1120 			err = -EINVAL;
1121 			break;
1122 		}
1123 		if (!pn->ifindex == !val)
1124 			break; /* Nothing to do! */
1125 		if (!capable(CAP_NET_ADMIN)) {
1126 			err = -EPERM;
1127 			break;
1128 		}
1129 		if (val) {
1130 			release_sock(sk);
1131 			err = gprs_attach(sk);
1132 			if (err > 0) {
1133 				pn->ifindex = err;
1134 				err = 0;
1135 			}
1136 		} else {
1137 			pn->ifindex = 0;
1138 			release_sock(sk);
1139 			gprs_detach(sk);
1140 			err = 0;
1141 		}
1142 		goto out_norel;
1143 
1144 #ifdef CONFIG_PHONET_PIPECTRLR
1145 	case PNPIPE_ENABLE:
1146 		if (pn->pipe_state <= PIPE_IDLE) {
1147 			err = -ENOTCONN;
1148 			break;
1149 		}
1150 		err = pipe_handler_enable_pipe(sk, val);
1151 		break;
1152 #endif
1153 
1154 	default:
1155 		err = -ENOPROTOOPT;
1156 	}
1157 	release_sock(sk);
1158 
1159 out_norel:
1160 	return err;
1161 }
1162 
1163 static int pep_getsockopt(struct sock *sk, int level, int optname,
1164 				char __user *optval, int __user *optlen)
1165 {
1166 	struct pep_sock *pn = pep_sk(sk);
1167 	int len, val;
1168 
1169 	if (level != SOL_PNPIPE)
1170 		return -ENOPROTOOPT;
1171 	if (get_user(len, optlen))
1172 		return -EFAULT;
1173 
1174 	switch (optname) {
1175 	case PNPIPE_ENCAP:
1176 		val = pn->ifindex ? PNPIPE_ENCAP_IP : PNPIPE_ENCAP_NONE;
1177 		break;
1178 
1179 	case PNPIPE_IFINDEX:
1180 		val = pn->ifindex;
1181 		break;
1182 
1183 #ifdef CONFIG_PHONET_PIPECTRLR
1184 	case PNPIPE_ENABLE:
1185 		if (pn->pipe_state <= PIPE_IDLE)
1186 			return -ENOTCONN;
1187 		val = pn->pipe_state != PIPE_DISABLED;
1188 		break;
1189 #endif
1190 
1191 	default:
1192 		return -ENOPROTOOPT;
1193 	}
1194 
1195 	len = min_t(unsigned int, sizeof(int), len);
1196 	if (put_user(len, optlen))
1197 		return -EFAULT;
1198 	if (put_user(val, (int __user *) optval))
1199 		return -EFAULT;
1200 	return 0;
1201 }
1202 
1203 static int pipe_skb_send(struct sock *sk, struct sk_buff *skb)
1204 {
1205 	struct pep_sock *pn = pep_sk(sk);
1206 	struct pnpipehdr *ph;
1207 	int err;
1208 
1209 	if (pn_flow_safe(pn->tx_fc) &&
1210 	    !atomic_add_unless(&pn->tx_credits, -1, 0)) {
1211 		kfree_skb(skb);
1212 		return -ENOBUFS;
1213 	}
1214 
1215 	skb_push(skb, 3 + pn->aligned);
1216 	skb_reset_transport_header(skb);
1217 	ph = pnp_hdr(skb);
1218 	ph->utid = 0;
1219 	if (pn->aligned) {
1220 		ph->message_id = PNS_PIPE_ALIGNED_DATA;
1221 		ph->data[0] = 0; /* padding */
1222 	} else
1223 		ph->message_id = PNS_PIPE_DATA;
1224 	ph->pipe_handle = pn->pipe_handle;
1225 #ifdef CONFIG_PHONET_PIPECTRLR
1226 	err = pn_skb_send(sk, skb, &pn->remote_pep);
1227 #else
1228 	err = pn_skb_send(sk, skb, &pipe_srv);
1229 #endif
1230 
1231 	if (err && pn_flow_safe(pn->tx_fc))
1232 		atomic_inc(&pn->tx_credits);
1233 	return err;
1234 
1235 }
1236 
1237 static int pep_sendmsg(struct kiocb *iocb, struct sock *sk,
1238 			struct msghdr *msg, size_t len)
1239 {
1240 	struct pep_sock *pn = pep_sk(sk);
1241 	struct sk_buff *skb;
1242 	long timeo;
1243 	int flags = msg->msg_flags;
1244 	int err, done;
1245 
1246 	if ((msg->msg_flags & ~(MSG_DONTWAIT|MSG_EOR|MSG_NOSIGNAL|
1247 				MSG_CMSG_COMPAT)) ||
1248 			!(msg->msg_flags & MSG_EOR))
1249 		return -EOPNOTSUPP;
1250 
1251 	skb = sock_alloc_send_skb(sk, MAX_PNPIPE_HEADER + len,
1252 					flags & MSG_DONTWAIT, &err);
1253 	if (!skb)
1254 		return err;
1255 
1256 	skb_reserve(skb, MAX_PHONET_HEADER + 3);
1257 	err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
1258 	if (err < 0)
1259 		goto outfree;
1260 
1261 	lock_sock(sk);
1262 	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
1263 	if ((1 << sk->sk_state) & (TCPF_LISTEN|TCPF_CLOSE)) {
1264 		err = -ENOTCONN;
1265 		goto out;
1266 	}
1267 	if (sk->sk_state != TCP_ESTABLISHED) {
1268 		/* Wait until the pipe gets to enabled state */
1269 disabled:
1270 		err = sk_stream_wait_connect(sk, &timeo);
1271 		if (err)
1272 			goto out;
1273 
1274 		if (sk->sk_state == TCP_CLOSE_WAIT) {
1275 			err = -ECONNRESET;
1276 			goto out;
1277 		}
1278 	}
1279 	BUG_ON(sk->sk_state != TCP_ESTABLISHED);
1280 
1281 	/* Wait until flow control allows TX */
1282 	done = atomic_read(&pn->tx_credits);
1283 	while (!done) {
1284 		DEFINE_WAIT(wait);
1285 
1286 		if (!timeo) {
1287 			err = -EAGAIN;
1288 			goto out;
1289 		}
1290 		if (signal_pending(current)) {
1291 			err = sock_intr_errno(timeo);
1292 			goto out;
1293 		}
1294 
1295 		prepare_to_wait(sk_sleep(sk), &wait,
1296 				TASK_INTERRUPTIBLE);
1297 		done = sk_wait_event(sk, &timeo, atomic_read(&pn->tx_credits));
1298 		finish_wait(sk_sleep(sk), &wait);
1299 
1300 		if (sk->sk_state != TCP_ESTABLISHED)
1301 			goto disabled;
1302 	}
1303 
1304 	err = pipe_skb_send(sk, skb);
1305 	if (err >= 0)
1306 		err = len; /* success! */
1307 	skb = NULL;
1308 out:
1309 	release_sock(sk);
1310 outfree:
1311 	kfree_skb(skb);
1312 	return err;
1313 }
1314 
1315 int pep_writeable(struct sock *sk)
1316 {
1317 	struct pep_sock *pn = pep_sk(sk);
1318 
1319 	return atomic_read(&pn->tx_credits);
1320 }
1321 
1322 int pep_write(struct sock *sk, struct sk_buff *skb)
1323 {
1324 	struct sk_buff *rskb, *fs;
1325 	int flen = 0;
1326 
1327 	if (pep_sk(sk)->aligned)
1328 		return pipe_skb_send(sk, skb);
1329 
1330 	rskb = alloc_skb(MAX_PNPIPE_HEADER, GFP_ATOMIC);
1331 	if (!rskb) {
1332 		kfree_skb(skb);
1333 		return -ENOMEM;
1334 	}
1335 	skb_shinfo(rskb)->frag_list = skb;
1336 	rskb->len += skb->len;
1337 	rskb->data_len += rskb->len;
1338 	rskb->truesize += rskb->len;
1339 
1340 	/* Avoid nested fragments */
1341 	skb_walk_frags(skb, fs)
1342 		flen += fs->len;
1343 	skb->next = skb_shinfo(skb)->frag_list;
1344 	skb_frag_list_init(skb);
1345 	skb->len -= flen;
1346 	skb->data_len -= flen;
1347 	skb->truesize -= flen;
1348 
1349 	skb_reserve(rskb, MAX_PHONET_HEADER + 3);
1350 	return pipe_skb_send(sk, rskb);
1351 }
1352 
1353 struct sk_buff *pep_read(struct sock *sk)
1354 {
1355 	struct sk_buff *skb = skb_dequeue(&sk->sk_receive_queue);
1356 
1357 	if (sk->sk_state == TCP_ESTABLISHED)
1358 		pipe_grant_credits(sk);
1359 	return skb;
1360 }
1361 
1362 static int pep_recvmsg(struct kiocb *iocb, struct sock *sk,
1363 			struct msghdr *msg, size_t len, int noblock,
1364 			int flags, int *addr_len)
1365 {
1366 	struct sk_buff *skb;
1367 	int err;
1368 
1369 	if (flags & ~(MSG_OOB|MSG_PEEK|MSG_TRUNC|MSG_DONTWAIT|MSG_WAITALL|
1370 			MSG_NOSIGNAL|MSG_CMSG_COMPAT))
1371 		return -EOPNOTSUPP;
1372 
1373 	if (unlikely(1 << sk->sk_state & (TCPF_LISTEN | TCPF_CLOSE)))
1374 		return -ENOTCONN;
1375 
1376 	if ((flags & MSG_OOB) || sock_flag(sk, SOCK_URGINLINE)) {
1377 		/* Dequeue and acknowledge control request */
1378 		struct pep_sock *pn = pep_sk(sk);
1379 
1380 		if (flags & MSG_PEEK)
1381 			return -EOPNOTSUPP;
1382 		skb = skb_dequeue(&pn->ctrlreq_queue);
1383 		if (skb) {
1384 			pep_ctrlreq_error(sk, skb, PN_PIPE_NO_ERROR,
1385 						GFP_KERNEL);
1386 			msg->msg_flags |= MSG_OOB;
1387 			goto copy;
1388 		}
1389 		if (flags & MSG_OOB)
1390 			return -EINVAL;
1391 	}
1392 
1393 	skb = skb_recv_datagram(sk, flags, noblock, &err);
1394 	lock_sock(sk);
1395 	if (skb == NULL) {
1396 		if (err == -ENOTCONN && sk->sk_state == TCP_CLOSE_WAIT)
1397 			err = -ECONNRESET;
1398 		release_sock(sk);
1399 		return err;
1400 	}
1401 
1402 	if (sk->sk_state == TCP_ESTABLISHED)
1403 		pipe_grant_credits(sk);
1404 	release_sock(sk);
1405 copy:
1406 	msg->msg_flags |= MSG_EOR;
1407 	if (skb->len > len)
1408 		msg->msg_flags |= MSG_TRUNC;
1409 	else
1410 		len = skb->len;
1411 
1412 	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, len);
1413 	if (!err)
1414 		err = (flags & MSG_TRUNC) ? skb->len : len;
1415 
1416 	skb_free_datagram(sk, skb);
1417 	return err;
1418 }
1419 
1420 static void pep_sock_unhash(struct sock *sk)
1421 {
1422 	struct pep_sock *pn = pep_sk(sk);
1423 	struct sock *skparent = NULL;
1424 
1425 	lock_sock(sk);
1426 
1427 #ifndef CONFIG_PHONET_PIPECTRLR
1428 	if ((1 << sk->sk_state) & ~(TCPF_CLOSE|TCPF_LISTEN)) {
1429 		skparent = pn->listener;
1430 		release_sock(sk);
1431 
1432 		pn = pep_sk(skparent);
1433 		lock_sock(skparent);
1434 		sk_del_node_init(sk);
1435 		sk = skparent;
1436 	}
1437 #endif
1438 	/* Unhash a listening sock only when it is closed
1439 	 * and all of its active connected pipes are closed. */
1440 	if (hlist_empty(&pn->hlist))
1441 		pn_sock_unhash(&pn->pn_sk.sk);
1442 	release_sock(sk);
1443 
1444 	if (skparent)
1445 		sock_put(skparent);
1446 }
1447 
1448 static struct proto pep_proto = {
1449 	.close		= pep_sock_close,
1450 	.accept		= pep_sock_accept,
1451 #ifdef CONFIG_PHONET_PIPECTRLR
1452 	.connect	= pep_sock_connect,
1453 #endif
1454 	.ioctl		= pep_ioctl,
1455 	.init		= pep_init,
1456 	.setsockopt	= pep_setsockopt,
1457 	.getsockopt	= pep_getsockopt,
1458 	.sendmsg	= pep_sendmsg,
1459 	.recvmsg	= pep_recvmsg,
1460 	.backlog_rcv	= pep_do_rcv,
1461 	.hash		= pn_sock_hash,
1462 	.unhash		= pep_sock_unhash,
1463 	.get_port	= pn_sock_get_port,
1464 	.obj_size	= sizeof(struct pep_sock),
1465 	.owner		= THIS_MODULE,
1466 	.name		= "PNPIPE",
1467 };
1468 
1469 static struct phonet_protocol pep_pn_proto = {
1470 	.ops		= &phonet_stream_ops,
1471 	.prot		= &pep_proto,
1472 	.sock_type	= SOCK_SEQPACKET,
1473 };
1474 
1475 static int __init pep_register(void)
1476 {
1477 	return phonet_proto_register(PN_PROTO_PIPE, &pep_pn_proto);
1478 }
1479 
1480 static void __exit pep_unregister(void)
1481 {
1482 	phonet_proto_unregister(PN_PROTO_PIPE, &pep_pn_proto);
1483 }
1484 
1485 module_init(pep_register);
1486 module_exit(pep_unregister);
1487 MODULE_AUTHOR("Remi Denis-Courmont, Nokia");
1488 MODULE_DESCRIPTION("Phonet pipe protocol");
1489 MODULE_LICENSE("GPL");
1490 MODULE_ALIAS_NET_PF_PROTO(PF_PHONET, PN_PROTO_PIPE);
1491