Phonet: Pipe End Point for Phonet Pipes protocol
[linux-2.6.git] / net / phonet / pep.c
1 /*
2  * File: pep.c
3  *
4  * Phonet pipe protocol end point socket
5  *
6  * Copyright (C) 2008 Nokia Corporation.
7  *
8  * Author: RĂ©mi 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/socket.h>
27 #include <net/sock.h>
28 #include <net/tcp_states.h>
29 #include <asm/ioctls.h>
30
31 #include <linux/phonet.h>
32 #include <net/phonet/phonet.h>
33 #include <net/phonet/pep.h>
34
35 /* sk_state values:
36  * TCP_CLOSE            sock not in use yet
37  * TCP_CLOSE_WAIT       disconnected pipe
38  * TCP_LISTEN           listening pipe endpoint
39  * TCP_SYN_RECV         connected pipe in disabled state
40  * TCP_ESTABLISHED      connected pipe in enabled state
41  *
42  * pep_sock locking:
43  *  - sk_state, ackq, hlist: sock lock needed
44  *  - listener: read only
45  *  - pipe_handle: read only
46  */
47
48 #define CREDITS_MAX     10
49 #define CREDITS_THR     7
50
51 static const struct sockaddr_pn pipe_srv = {
52         .spn_family = AF_PHONET,
53         .spn_resource = 0xD9, /* pipe service */
54 };
55
56 #define pep_sb_size(s) (((s) + 5) & ~3) /* 2-bytes head, 32-bits aligned */
57
58 /* Get the next TLV sub-block. */
59 static unsigned char *pep_get_sb(struct sk_buff *skb, u8 *ptype, u8 *plen,
60                                         void *buf)
61 {
62         void *data = NULL;
63         struct {
64                 u8 sb_type;
65                 u8 sb_len;
66         } *ph, h;
67         int buflen = *plen;
68
69         ph = skb_header_pointer(skb, 0, 2, &h);
70         if (ph == NULL || ph->sb_len < 2 || !pskb_may_pull(skb, ph->sb_len))
71                 return NULL;
72         ph->sb_len -= 2;
73         *ptype = ph->sb_type;
74         *plen = ph->sb_len;
75
76         if (buflen > ph->sb_len)
77                 buflen = ph->sb_len;
78         data = skb_header_pointer(skb, 2, buflen, buf);
79         __skb_pull(skb, 2 + ph->sb_len);
80         return data;
81 }
82
83 static int pep_reply(struct sock *sk, struct sk_buff *oskb,
84                         u8 code, const void *data, int len, gfp_t priority)
85 {
86         const struct pnpipehdr *oph = pnp_hdr(oskb);
87         struct pnpipehdr *ph;
88         struct sk_buff *skb;
89
90         skb = alloc_skb(MAX_PNPIPE_HEADER + len, priority);
91         if (!skb)
92                 return -ENOMEM;
93         skb_set_owner_w(skb, sk);
94
95         skb_reserve(skb, MAX_PNPIPE_HEADER);
96         __skb_put(skb, len);
97         skb_copy_to_linear_data(skb, data, len);
98         __skb_push(skb, sizeof(*ph));
99         skb_reset_transport_header(skb);
100         ph = pnp_hdr(skb);
101         ph->utid = oph->utid;
102         ph->message_id = oph->message_id + 1; /* REQ -> RESP */
103         ph->pipe_handle = oph->pipe_handle;
104         ph->error_code = code;
105
106         return pn_skb_send(sk, skb, &pipe_srv);
107 }
108
109 #define PAD 0x00
110 static int pep_accept_conn(struct sock *sk, struct sk_buff *skb)
111 {
112         static const u8 data[20] = {
113                 PAD, PAD, PAD, 2 /* sub-blocks */,
114                 PN_PIPE_SB_REQUIRED_FC_TX, pep_sb_size(5), 3, PAD,
115                         PN_MULTI_CREDIT_FLOW_CONTROL,
116                         PN_ONE_CREDIT_FLOW_CONTROL,
117                         PN_LEGACY_FLOW_CONTROL,
118                         PAD,
119                 PN_PIPE_SB_PREFERRED_FC_RX, pep_sb_size(5), 3, PAD,
120                         PN_MULTI_CREDIT_FLOW_CONTROL,
121                         PN_ONE_CREDIT_FLOW_CONTROL,
122                         PN_LEGACY_FLOW_CONTROL,
123                         PAD,
124         };
125
126         might_sleep();
127         return pep_reply(sk, skb, PN_PIPE_NO_ERROR, data, sizeof(data),
128                                 GFP_KERNEL);
129 }
130
131 static int pep_reject_conn(struct sock *sk, struct sk_buff *skb, u8 code)
132 {
133         static const u8 data[4] = { PAD, PAD, PAD, 0 /* sub-blocks */ };
134         WARN_ON(code == PN_PIPE_NO_ERROR);
135         return pep_reply(sk, skb, code, data, sizeof(data), GFP_ATOMIC);
136 }
137
138 /* Control requests are not sent by the pipe service and have a specific
139  * message format. */
140 static int pep_ctrlreq_error(struct sock *sk, struct sk_buff *oskb, u8 code)
141 {
142         const struct pnpipehdr *oph = pnp_hdr(oskb);
143         struct sk_buff *skb;
144         struct pnpipehdr *ph;
145         struct sockaddr_pn dst;
146
147         skb = alloc_skb(MAX_PNPIPE_HEADER + 4, GFP_ATOMIC);
148         if (!skb)
149                 return -ENOMEM;
150         skb_set_owner_w(skb, sk);
151
152         skb_reserve(skb, MAX_PHONET_HEADER);
153         ph = (struct pnpipehdr *)skb_put(skb, sizeof(*ph) + 4);
154
155         ph->utid = oph->utid;
156         ph->message_id = PNS_PEP_CTRL_RESP;
157         ph->pipe_handle = oph->pipe_handle;
158         ph->data[0] = oph->data[1]; /* CTRL id */
159         ph->data[1] = oph->data[0]; /* PEP type */
160         ph->data[2] = code; /* error code, at an usual offset */
161         ph->data[3] = PAD;
162         ph->data[4] = PAD;
163
164         pn_skb_get_src_sockaddr(oskb, &dst);
165         return pn_skb_send(sk, skb, &dst);
166 }
167
168 static int pipe_snd_status(struct sock *sk, u8 type, u8 status, gfp_t priority)
169 {
170         struct pep_sock *pn = pep_sk(sk);
171         struct pnpipehdr *ph;
172         struct sk_buff *skb;
173
174         skb = alloc_skb(MAX_PNPIPE_HEADER + 4, priority);
175         if (!skb)
176                 return -ENOMEM;
177         skb_set_owner_w(skb, sk);
178
179         skb_reserve(skb, MAX_PNPIPE_HEADER + 4);
180         __skb_push(skb, sizeof(*ph) + 4);
181         skb_reset_transport_header(skb);
182         ph = pnp_hdr(skb);
183         ph->utid = 0;
184         ph->message_id = PNS_PEP_STATUS_IND;
185         ph->pipe_handle = pn->pipe_handle;
186         ph->pep_type = PN_PEP_TYPE_COMMON;
187         ph->data[1] = type;
188         ph->data[2] = PAD;
189         ph->data[3] = PAD;
190         ph->data[4] = status;
191
192         return pn_skb_send(sk, skb, &pipe_srv);
193 }
194
195 /* Send our RX flow control information to the sender.
196  * Socket must be locked. */
197 static void pipe_grant_credits(struct sock *sk)
198 {
199         struct pep_sock *pn = pep_sk(sk);
200
201         BUG_ON(sk->sk_state != TCP_ESTABLISHED);
202
203         switch (pn->rx_fc) {
204         case PN_LEGACY_FLOW_CONTROL: /* TODO */
205                 break;
206         case PN_ONE_CREDIT_FLOW_CONTROL:
207                 pipe_snd_status(sk, PN_PEP_IND_FLOW_CONTROL,
208                                 PEP_IND_READY, GFP_ATOMIC);
209                 pn->rx_credits = 1;
210                 break;
211         case PN_MULTI_CREDIT_FLOW_CONTROL:
212                 if ((pn->rx_credits + CREDITS_THR) > CREDITS_MAX)
213                         break;
214                 if (pipe_snd_status(sk, PN_PEP_IND_ID_MCFC_GRANT_CREDITS,
215                                         CREDITS_MAX - pn->rx_credits,
216                                         GFP_ATOMIC) == 0)
217                         pn->rx_credits = CREDITS_MAX;
218                 break;
219         }
220 }
221
222 static int pipe_rcv_status(struct sock *sk, struct sk_buff *skb)
223 {
224         struct pep_sock *pn = pep_sk(sk);
225         struct pnpipehdr *hdr = pnp_hdr(skb);
226
227         if (!pskb_may_pull(skb, sizeof(*hdr) + 4))
228                 return -EINVAL;
229
230         if (hdr->data[0] != PN_PEP_TYPE_COMMON) {
231                 LIMIT_NETDEBUG(KERN_DEBUG"Phonet unknown PEP type: %u\n",
232                                 (unsigned)hdr->data[0]);
233                 return -EOPNOTSUPP;
234         }
235
236         switch (hdr->data[1]) {
237         case PN_PEP_IND_FLOW_CONTROL:
238                 switch (pn->tx_fc) {
239                 case PN_LEGACY_FLOW_CONTROL:
240                         switch (hdr->data[4]) {
241                         case PEP_IND_BUSY:
242                                 pn->tx_credits = 0;
243                                 break;
244                         case PEP_IND_READY:
245                                 pn->tx_credits = 1;
246                                 break;
247                         }
248                         break;
249                 case PN_ONE_CREDIT_FLOW_CONTROL:
250                         if (hdr->data[4] == PEP_IND_READY)
251                                 pn->tx_credits = 1;
252                         break;
253                 }
254                 break;
255
256         case PN_PEP_IND_ID_MCFC_GRANT_CREDITS:
257                 if (pn->tx_fc != PN_MULTI_CREDIT_FLOW_CONTROL)
258                         break;
259                 if (pn->tx_credits + hdr->data[4] > 0xff)
260                         pn->tx_credits = 0xff;
261                 else
262                         pn->tx_credits += hdr->data[4];
263                 break;
264
265         default:
266                 LIMIT_NETDEBUG(KERN_DEBUG"Phonet unknown PEP indication: %u\n",
267                                 (unsigned)hdr->data[1]);
268                 return -EOPNOTSUPP;
269         }
270         if (pn->tx_credits)
271                 sk->sk_write_space(sk);
272         return 0;
273 }
274
275 static int pipe_rcv_created(struct sock *sk, struct sk_buff *skb)
276 {
277         struct pep_sock *pn = pep_sk(sk);
278         struct pnpipehdr *hdr = pnp_hdr(skb);
279         u8 n_sb = hdr->data[0];
280
281         pn->rx_fc = pn->tx_fc = PN_LEGACY_FLOW_CONTROL;
282         __skb_pull(skb, sizeof(*hdr));
283         while (n_sb > 0) {
284                 u8 type, buf[2], len = sizeof(buf);
285                 u8 *data = pep_get_sb(skb, &type, &len, buf);
286
287                 if (data == NULL)
288                         return -EINVAL;
289                 switch (type) {
290                 case PN_PIPE_SB_NEGOTIATED_FC:
291                         if (len < 2 || (data[0] | data[1]) > 3)
292                                 break;
293                         pn->tx_fc = data[0] & 3;
294                         pn->rx_fc = data[1] & 3;
295                         break;
296                 }
297                 n_sb--;
298         }
299         return 0;
300 }
301
302 /* Queue an skb to a connected sock.
303  * Socket lock must be held. */
304 static int pipe_do_rcv(struct sock *sk, struct sk_buff *skb)
305 {
306         struct pep_sock *pn = pep_sk(sk);
307         struct pnpipehdr *hdr = pnp_hdr(skb);
308         int err = 0;
309
310         BUG_ON(sk->sk_state == TCP_CLOSE_WAIT);
311
312         switch (hdr->message_id) {
313         case PNS_PEP_CONNECT_REQ:
314                 pep_reject_conn(sk, skb, PN_PIPE_ERR_PEP_IN_USE);
315                 break;
316
317         case PNS_PEP_DISCONNECT_REQ:
318                 pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC);
319                 sk->sk_state = TCP_CLOSE_WAIT;
320                 if (!sock_flag(sk, SOCK_DEAD))
321                         sk->sk_state_change(sk);
322                 break;
323
324         case PNS_PEP_ENABLE_REQ:
325                 /* Wait for PNS_PIPE_(ENABLED|REDIRECTED)_IND */
326                 pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC);
327                 break;
328
329         case PNS_PEP_RESET_REQ:
330                 switch (hdr->state_after_reset) {
331                 case PN_PIPE_DISABLE:
332                         pn->init_enable = 0;
333                         break;
334                 case PN_PIPE_ENABLE:
335                         pn->init_enable = 1;
336                         break;
337                 default: /* not allowed to send an error here!? */
338                         err = -EINVAL;
339                         goto out;
340                 }
341                 /* fall through */
342         case PNS_PEP_DISABLE_REQ:
343                 pn->tx_credits = 0;
344                 pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC);
345                 break;
346
347         case PNS_PEP_CTRL_REQ:
348                 /* TODO */
349                 pep_ctrlreq_error(sk, skb, PN_PIPE_NO_ERROR);
350                 break;
351
352         case PNS_PIPE_DATA:
353                 __skb_pull(skb, 3); /* Pipe data header */
354                 if (!pn_flow_safe(pn->rx_fc)) {
355                         err = sock_queue_rcv_skb(sk, skb);
356                         if (!err)
357                                 return 0;
358                         break;
359                 }
360
361                 if (pn->rx_credits == 0) {
362                         err = -ENOBUFS;
363                         break;
364                 }
365                 pn->rx_credits--;
366                 skb->dev = NULL;
367                 skb_set_owner_r(skb, sk);
368                 err = skb->len;
369                 skb_queue_tail(&sk->sk_receive_queue, skb);
370                 if (!sock_flag(sk, SOCK_DEAD))
371                         sk->sk_data_ready(sk, err);
372                 return 0;
373
374         case PNS_PEP_STATUS_IND:
375                 pipe_rcv_status(sk, skb);
376                 break;
377
378         case PNS_PIPE_REDIRECTED_IND:
379                 err = pipe_rcv_created(sk, skb);
380                 break;
381
382         case PNS_PIPE_CREATED_IND:
383                 err = pipe_rcv_created(sk, skb);
384                 if (err)
385                         break;
386                 /* fall through */
387         case PNS_PIPE_RESET_IND:
388                 if (!pn->init_enable)
389                         break;
390                 /* fall through */
391         case PNS_PIPE_ENABLED_IND:
392                 if (!pn_flow_safe(pn->tx_fc)) {
393                         pn->tx_credits = 1;
394                         sk->sk_write_space(sk);
395                 }
396                 if (sk->sk_state == TCP_ESTABLISHED)
397                         break; /* Nothing to do */
398                 sk->sk_state = TCP_ESTABLISHED;
399                 pipe_grant_credits(sk);
400                 break;
401
402         case PNS_PIPE_DISABLED_IND:
403                 sk->sk_state = TCP_SYN_RECV;
404                 pn->rx_credits = 0;
405                 break;
406
407         default:
408                 LIMIT_NETDEBUG(KERN_DEBUG"Phonet unknown PEP message: %u\n",
409                                 hdr->message_id);
410                 err = -EINVAL;
411         }
412 out:
413         kfree_skb(skb);
414         return err;
415 }
416
417 /* Destroy connected sock. */
418 static void pipe_destruct(struct sock *sk)
419 {
420         skb_queue_purge(&sk->sk_receive_queue);
421 }
422
423 static int pep_connreq_rcv(struct sock *sk, struct sk_buff *skb)
424 {
425         struct sock *newsk;
426         struct pep_sock *newpn, *pn = pep_sk(sk);
427         struct pnpipehdr *hdr;
428         struct sockaddr_pn dst;
429         u16 peer_type;
430         u8 pipe_handle, enabled, n_sb;
431
432         if (!pskb_pull(skb, sizeof(*hdr) + 4))
433                 return -EINVAL;
434
435         hdr = pnp_hdr(skb);
436         pipe_handle = hdr->pipe_handle;
437         switch (hdr->state_after_connect) {
438         case PN_PIPE_DISABLE:
439                 enabled = 0;
440                 break;
441         case PN_PIPE_ENABLE:
442                 enabled = 1;
443                 break;
444         default:
445                 pep_reject_conn(sk, skb, PN_PIPE_ERR_INVALID_PARAM);
446                 return -EINVAL;
447         }
448         peer_type = hdr->other_pep_type << 8;
449
450         if (unlikely(sk->sk_state != TCP_LISTEN) || sk_acceptq_is_full(sk)) {
451                 pep_reject_conn(sk, skb, PN_PIPE_ERR_PEP_IN_USE);
452                 return -ENOBUFS;
453         }
454
455         /* Parse sub-blocks (options) */
456         n_sb = hdr->data[4];
457         while (n_sb > 0) {
458                 u8 type, buf[1], len = sizeof(buf);
459                 const u8 *data = pep_get_sb(skb, &type, &len, buf);
460
461                 if (data == NULL)
462                         return -EINVAL;
463                 switch (type) {
464                 case PN_PIPE_SB_CONNECT_REQ_PEP_SUB_TYPE:
465                         if (len < 1)
466                                 return -EINVAL;
467                         peer_type = (peer_type & 0xff00) | data[0];
468                         break;
469                 }
470                 n_sb--;
471         }
472
473         skb = skb_clone(skb, GFP_ATOMIC);
474         if (!skb)
475                 return -ENOMEM;
476
477         /* Create a new to-be-accepted sock */
478         newsk = sk_alloc(sock_net(sk), PF_PHONET, GFP_ATOMIC, sk->sk_prot);
479         if (!newsk) {
480                 kfree_skb(skb);
481                 return -ENOMEM;
482         }
483         sock_init_data(NULL, newsk);
484         newsk->sk_state = TCP_SYN_RECV;
485         newsk->sk_backlog_rcv = pipe_do_rcv;
486         newsk->sk_protocol = sk->sk_protocol;
487         newsk->sk_destruct = pipe_destruct;
488
489         newpn = pep_sk(newsk);
490         pn_skb_get_dst_sockaddr(skb, &dst);
491         newpn->pn_sk.sobject = pn_sockaddr_get_object(&dst);
492         newpn->pn_sk.resource = pn->pn_sk.resource;
493         newpn->pipe_handle = pipe_handle;
494         newpn->peer_type = peer_type;
495         newpn->rx_credits = newpn->tx_credits = 0;
496         newpn->rx_fc = newpn->tx_fc = PN_LEGACY_FLOW_CONTROL;
497         newpn->init_enable = enabled;
498
499         BUG_ON(!skb_queue_empty(&newsk->sk_receive_queue));
500         skb_queue_head(&newsk->sk_receive_queue, skb);
501         if (!sock_flag(sk, SOCK_DEAD))
502                 sk->sk_data_ready(sk, 0);
503
504         sk_acceptq_added(sk);
505         sk_add_node(newsk, &pn->ackq);
506         return 0;
507 }
508
509 /* Listening sock must be locked */
510 static struct sock *pep_find_pipe(const struct hlist_head *hlist,
511                                         const struct sockaddr_pn *dst,
512                                         u8 pipe_handle)
513 {
514         struct hlist_node *node;
515         struct sock *sknode;
516         u16 dobj = pn_sockaddr_get_object(dst);
517
518         sk_for_each(sknode, node, hlist) {
519                 struct pep_sock *pnnode = pep_sk(sknode);
520
521                 /* Ports match, but addresses might not: */
522                 if (pnnode->pn_sk.sobject != dobj)
523                         continue;
524                 if (pnnode->pipe_handle != pipe_handle)
525                         continue;
526                 if (sknode->sk_state == TCP_CLOSE_WAIT)
527                         continue;
528
529                 sock_hold(sknode);
530                 return sknode;
531         }
532         return NULL;
533 }
534
535 /*
536  * Deliver an skb to a listening sock.
537  * Socket lock must be held.
538  * We then queue the skb to the right connected sock (if any).
539  */
540 static int pep_do_rcv(struct sock *sk, struct sk_buff *skb)
541 {
542         struct pep_sock *pn = pep_sk(sk);
543         struct sock *sknode;
544         struct pnpipehdr *hdr = pnp_hdr(skb);
545         struct sockaddr_pn dst;
546         int err = NET_RX_SUCCESS;
547         u8 pipe_handle;
548
549         if (!pskb_may_pull(skb, sizeof(*hdr)))
550                 goto drop;
551
552         hdr = pnp_hdr(skb);
553         pipe_handle = hdr->pipe_handle;
554         if (pipe_handle == PN_PIPE_INVALID_HANDLE)
555                 goto drop;
556
557         pn_skb_get_dst_sockaddr(skb, &dst);
558
559         /* Look for an existing pipe handle */
560         sknode = pep_find_pipe(&pn->hlist, &dst, pipe_handle);
561         if (sknode)
562                 return sk_receive_skb(sknode, skb, 1);
563
564         /* Look for a pipe handle pending accept */
565         sknode = pep_find_pipe(&pn->ackq, &dst, pipe_handle);
566         if (sknode) {
567                 sock_put(sknode);
568                 if (net_ratelimit())
569                         printk(KERN_WARNING"Phonet unconnected PEP ignored");
570                 err = NET_RX_DROP;
571                 goto drop;
572         }
573
574         switch (hdr->message_id) {
575         case PNS_PEP_CONNECT_REQ:
576                 err = pep_connreq_rcv(sk, skb);
577                 break;
578
579         case PNS_PEP_DISCONNECT_REQ:
580                 pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC);
581                 break;
582
583         case PNS_PEP_CTRL_REQ:
584                 pep_ctrlreq_error(sk, skb, PN_PIPE_INVALID_HANDLE);
585                 break;
586
587         case PNS_PEP_RESET_REQ:
588         case PNS_PEP_ENABLE_REQ:
589         case PNS_PEP_DISABLE_REQ:
590                 /* invalid handle is not even allowed here! */
591         default:
592                 err = NET_RX_DROP;
593         }
594 drop:
595         kfree_skb(skb);
596         return err;
597 }
598
599 /* associated socket ceases to exist */
600 static void pep_sock_close(struct sock *sk, long timeout)
601 {
602         struct pep_sock *pn = pep_sk(sk);
603
604         sk_common_release(sk);
605
606         lock_sock(sk);
607         if (sk->sk_state == TCP_LISTEN) {
608                 /* Destroy the listen queue */
609                 struct sock *sknode;
610                 struct hlist_node *p, *n;
611
612                 sk_for_each_safe(sknode, p, n, &pn->ackq)
613                         sk_del_node_init(sknode);
614                 sk->sk_state = TCP_CLOSE;
615         }
616         release_sock(sk);
617 }
618
619 static int pep_wait_connreq(struct sock *sk, int noblock)
620 {
621         struct task_struct *tsk = current;
622         struct pep_sock *pn = pep_sk(sk);
623         long timeo = sock_rcvtimeo(sk, noblock);
624
625         for (;;) {
626                 DEFINE_WAIT(wait);
627
628                 if (sk->sk_state != TCP_LISTEN)
629                         return -EINVAL;
630                 if (!hlist_empty(&pn->ackq))
631                         break;
632                 if (!timeo)
633                         return -EWOULDBLOCK;
634                 if (signal_pending(tsk))
635                         return sock_intr_errno(timeo);
636
637                 prepare_to_wait_exclusive(&sk->sk_socket->wait, &wait,
638                                                 TASK_INTERRUPTIBLE);
639                 release_sock(sk);
640                 timeo = schedule_timeout(timeo);
641                 lock_sock(sk);
642                 finish_wait(&sk->sk_socket->wait, &wait);
643         }
644
645         return 0;
646 }
647
648 static struct sock *pep_sock_accept(struct sock *sk, int flags, int *errp)
649 {
650         struct pep_sock *pn = pep_sk(sk);
651         struct sock *newsk = NULL;
652         struct sk_buff *oskb;
653         int err;
654
655         lock_sock(sk);
656         err = pep_wait_connreq(sk, flags & O_NONBLOCK);
657         if (err)
658                 goto out;
659
660         newsk = __sk_head(&pn->ackq);
661
662         oskb = skb_dequeue(&newsk->sk_receive_queue);
663         err = pep_accept_conn(newsk, oskb);
664         if (err) {
665                 skb_queue_head(&newsk->sk_receive_queue, oskb);
666                 newsk = NULL;
667                 goto out;
668         }
669
670         sock_hold(sk);
671         pep_sk(newsk)->listener = sk;
672
673         sock_hold(newsk);
674         sk_del_node_init(newsk);
675         sk_acceptq_removed(sk);
676         sk_add_node(newsk, &pn->hlist);
677         __sock_put(newsk);
678
679 out:
680         release_sock(sk);
681         *errp = err;
682         return newsk;
683 }
684
685 static int pep_ioctl(struct sock *sk, int cmd, unsigned long arg)
686 {
687         int answ;
688
689         switch (cmd) {
690         case SIOCINQ:
691                 if (sk->sk_state == TCP_LISTEN)
692                         return -EINVAL;
693
694                 lock_sock(sk);
695                 if (!skb_queue_empty(&sk->sk_receive_queue))
696                         answ = skb_peek(&sk->sk_receive_queue)->len;
697                 else
698                         answ = 0;
699                 release_sock(sk);
700                 return put_user(answ, (int __user *)arg);
701         }
702
703         return -ENOIOCTLCMD;
704 }
705
706 static int pep_init(struct sock *sk)
707 {
708         struct pep_sock *pn = pep_sk(sk);
709
710         INIT_HLIST_HEAD(&pn->ackq);
711         INIT_HLIST_HEAD(&pn->hlist);
712         pn->pipe_handle = PN_PIPE_INVALID_HANDLE;
713         return 0;
714 }
715
716 static int pep_sendmsg(struct kiocb *iocb, struct sock *sk,
717                         struct msghdr *msg, size_t len)
718 {
719         struct pep_sock *pn = pep_sk(sk);
720         struct sk_buff *skb = NULL;
721         struct pnpipehdr *ph;
722         long timeo;
723         int flags = msg->msg_flags;
724         int err, done;
725
726         if (msg->msg_flags & MSG_OOB || !(msg->msg_flags & MSG_EOR))
727                 return -EOPNOTSUPP;
728
729         lock_sock(sk);
730         timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
731         if ((1 << sk->sk_state) & (TCPF_LISTEN|TCPF_CLOSE)) {
732                 err = -ENOTCONN;
733                 goto out;
734         }
735         if (sk->sk_state != TCP_ESTABLISHED) {
736                 /* Wait until the pipe gets to enabled state */
737 disabled:
738                 err = sk_stream_wait_connect(sk, &timeo);
739                 if (err)
740                         goto out;
741
742                 if (sk->sk_state == TCP_CLOSE_WAIT) {
743                         err = -ECONNRESET;
744                         goto out;
745                 }
746         }
747         BUG_ON(sk->sk_state != TCP_ESTABLISHED);
748
749         /* Wait until flow control allows TX */
750         done = pn->tx_credits > 0;
751         while (!done) {
752                 DEFINE_WAIT(wait);
753
754                 if (!timeo) {
755                         err = -EAGAIN;
756                         goto out;
757                 }
758                 if (signal_pending(current)) {
759                         err = sock_intr_errno(timeo);
760                         goto out;
761                 }
762
763                 prepare_to_wait(&sk->sk_socket->wait, &wait,
764                                 TASK_INTERRUPTIBLE);
765                 done = sk_wait_event(sk, &timeo, pn->tx_credits > 0);
766                 finish_wait(&sk->sk_socket->wait, &wait);
767
768                 if (sk->sk_state != TCP_ESTABLISHED)
769                         goto disabled;
770         }
771
772         if (!skb) {
773                 skb = sock_alloc_send_skb(sk, MAX_PNPIPE_HEADER + len,
774                                                 flags & MSG_DONTWAIT, &err);
775                 if (skb == NULL)
776                         goto out;
777                 skb_reserve(skb, MAX_PHONET_HEADER + 3);
778
779                 if (sk->sk_state != TCP_ESTABLISHED || !pn->tx_credits)
780                         goto disabled; /* sock_alloc_send_skb might sleep */
781         }
782
783         err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
784         if (err < 0)
785                 goto out;
786
787         __skb_push(skb, 3);
788         skb_reset_transport_header(skb);
789         ph = pnp_hdr(skb);
790         ph->utid = 0;
791         ph->message_id = PNS_PIPE_DATA;
792         ph->pipe_handle = pn->pipe_handle;
793         if (pn_flow_safe(pn->tx_fc)) /* credit-based flow control */
794                 pn->tx_credits--;
795
796         err = pn_skb_send(sk, skb, &pipe_srv);
797         if (err >= 0)
798                 err = len; /* success! */
799         skb = NULL;
800 out:
801         release_sock(sk);
802         kfree_skb(skb);
803         return err;
804 }
805
806 static int pep_recvmsg(struct kiocb *iocb, struct sock *sk,
807                         struct msghdr *msg, size_t len, int noblock,
808                         int flags, int *addr_len)
809 {
810         struct sk_buff *skb;
811         int err;
812
813         if (unlikely(flags & MSG_OOB))
814                 return -EOPNOTSUPP;
815         if (unlikely(1 << sk->sk_state & (TCPF_LISTEN | TCPF_CLOSE)))
816                 return -ENOTCONN;
817
818         skb = skb_recv_datagram(sk, flags, noblock, &err);
819         lock_sock(sk);
820         if (skb == NULL) {
821                 if (err == -ENOTCONN && sk->sk_state == TCP_CLOSE_WAIT)
822                         err = -ECONNRESET;
823                 release_sock(sk);
824                 return err;
825         }
826
827         if (sk->sk_state == TCP_ESTABLISHED)
828                 pipe_grant_credits(sk);
829         release_sock(sk);
830
831         msg->msg_flags |= MSG_EOR;
832
833         if (skb->len > len)
834                 msg->msg_flags |= MSG_TRUNC;
835         else
836                 len = skb->len;
837
838         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, len);
839         if (!err)
840                 err = (flags & MSG_TRUNC) ? skb->len : len;
841
842         skb_free_datagram(sk, skb);
843         return err;
844 }
845
846 static void pep_sock_unhash(struct sock *sk)
847 {
848         struct pep_sock *pn = pep_sk(sk);
849         struct sock *skparent = NULL;
850
851         lock_sock(sk);
852         if ((1 << sk->sk_state) & ~(TCPF_CLOSE|TCPF_LISTEN)) {
853                 skparent = pn->listener;
854                 sk_del_node_init(sk);
855                 release_sock(sk);
856
857                 sk = skparent;
858                 pn = pep_sk(skparent);
859                 lock_sock(sk);
860         }
861         /* Unhash a listening sock only when it is closed
862          * and all of its active connected pipes are closed. */
863         if (hlist_empty(&pn->hlist))
864                 pn_sock_unhash(&pn->pn_sk.sk);
865         release_sock(sk);
866
867         if (skparent)
868                 sock_put(skparent);
869 }
870
871 static struct proto pep_proto = {
872         .close          = pep_sock_close,
873         .accept         = pep_sock_accept,
874         .ioctl          = pep_ioctl,
875         .init           = pep_init,
876         .sendmsg        = pep_sendmsg,
877         .recvmsg        = pep_recvmsg,
878         .backlog_rcv    = pep_do_rcv,
879         .hash           = pn_sock_hash,
880         .unhash         = pep_sock_unhash,
881         .get_port       = pn_sock_get_port,
882         .obj_size       = sizeof(struct pep_sock),
883         .owner          = THIS_MODULE,
884         .name           = "PNPIPE",
885 };
886
887 static struct phonet_protocol pep_pn_proto = {
888         .ops            = &phonet_stream_ops,
889         .prot           = &pep_proto,
890         .sock_type      = SOCK_SEQPACKET,
891 };
892
893 static int __init pep_register(void)
894 {
895         return phonet_proto_register(PN_PROTO_PIPE, &pep_pn_proto);
896 }
897
898 static void __exit pep_unregister(void)
899 {
900         phonet_proto_unregister(PN_PROTO_PIPE, &pep_pn_proto);
901 }
902
903 module_init(pep_register);
904 module_exit(pep_unregister);
905 MODULE_AUTHOR("Remi Denis-Courmont, Nokia");
906 MODULE_DESCRIPTION("Phonet pipe protocol");
907 MODULE_LICENSE("GPL");
908 MODULE_ALIAS_NET_PF_PROTO(PF_PHONET, PN_PROTO_PIPE);