1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Fd transport layer. Includes deprecated socket layer.
4 *
5 * Copyright (C) 2006 by Russ Cox <rsc@swtch.com>
6 * Copyright (C) 2004-2005 by Latchesar Ionkov <lucho@ionkov.net>
7 * Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
8 * Copyright (C) 1997-2002 by Ron Minnich <rminnich@sarnoff.com>
9 */
10
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13 #include <linux/in.h>
14 #include <linux/module.h>
15 #include <linux/net.h>
16 #include <linux/ipv6.h>
17 #include <linux/kthread.h>
18 #include <linux/errno.h>
19 #include <linux/kernel.h>
20 #include <linux/un.h>
21 #include <linux/uaccess.h>
22 #include <linux/inet.h>
23 #include <linux/file.h>
24 #include <linux/parser.h>
25 #include <linux/slab.h>
26 #include <linux/seq_file.h>
27 #include <net/9p/9p.h>
28 #include <net/9p/client.h>
29 #include <net/9p/transport.h>
30
31 #include <linux/syscalls.h> /* killme */
32
33 #define P9_PORT 564
34 #define MAX_SOCK_BUF (1024*1024)
35 #define MAXPOLLWADDR 2
36
37 static struct p9_trans_module p9_tcp_trans;
38 static struct p9_trans_module p9_fd_trans;
39
40 /**
41 * struct p9_fd_opts - per-transport options
42 * @rfd: file descriptor for reading (trans=fd)
43 * @wfd: file descriptor for writing (trans=fd)
44 * @port: port to connect to (trans=tcp)
45 * @privport: port is privileged
46 */
47
48 struct p9_fd_opts {
49 int rfd;
50 int wfd;
51 u16 port;
52 bool privport;
53 };
54
55 /*
56 * Option Parsing (code inspired by NFS code)
57 * - a little lazy - parse all fd-transport options
58 */
59
60 enum {
61 /* Options that take integer arguments */
62 Opt_port, Opt_rfdno, Opt_wfdno, Opt_err,
63 /* Options that take no arguments */
64 Opt_privport,
65 };
66
67 static const match_table_t tokens = {
68 {Opt_port, "port=%u"},
69 {Opt_rfdno, "rfdno=%u"},
70 {Opt_wfdno, "wfdno=%u"},
71 {Opt_privport, "privport"},
72 {Opt_err, NULL},
73 };
74
75 enum {
76 Rworksched = 1, /* read work scheduled or running */
77 Rpending = 2, /* can read */
78 Wworksched = 4, /* write work scheduled or running */
79 Wpending = 8, /* can write */
80 };
81
82 struct p9_poll_wait {
83 struct p9_conn *conn;
84 wait_queue_entry_t wait;
85 wait_queue_head_t *wait_addr;
86 };
87
88 /**
89 * struct p9_conn - fd mux connection state information
90 * @mux_list: list link for mux to manage multiple connections (?)
91 * @client: reference to client instance for this connection
92 * @err: error state
93 * @req_lock: lock protecting req_list and requests statuses
94 * @req_list: accounting for requests which have been sent
95 * @unsent_req_list: accounting for requests that haven't been sent
96 * @rreq: read request
97 * @wreq: write request
98 * @req: current request being processed (if any)
99 * @tmp_buf: temporary buffer to read in header
100 * @rc: temporary fcall for reading current frame
101 * @wpos: write position for current frame
102 * @wsize: amount of data to write for current frame
103 * @wbuf: current write buffer
104 * @poll_pending_link: pending links to be polled per conn
105 * @poll_wait: array of wait_q's for various worker threads
106 * @pt: poll state
107 * @rq: current read work
108 * @wq: current write work
109 * @wsched: ????
110 *
111 */
112
113 struct p9_conn {
114 struct list_head mux_list;
115 struct p9_client *client;
116 int err;
117 spinlock_t req_lock;
118 struct list_head req_list;
119 struct list_head unsent_req_list;
120 struct p9_req_t *rreq;
121 struct p9_req_t *wreq;
122 char tmp_buf[P9_HDRSZ];
123 struct p9_fcall rc;
124 int wpos;
125 int wsize;
126 char *wbuf;
127 struct list_head poll_pending_link;
128 struct p9_poll_wait poll_wait[MAXPOLLWADDR];
129 poll_table pt;
130 struct work_struct rq;
131 struct work_struct wq;
132 unsigned long wsched;
133 };
134
135 /**
136 * struct p9_trans_fd - transport state
137 * @rd: reference to file to read from
138 * @wr: reference of file to write to
139 * @conn: connection state reference
140 *
141 */
142
143 struct p9_trans_fd {
144 struct file *rd;
145 struct file *wr;
146 struct p9_conn conn;
147 };
148
149 static void p9_poll_workfn(struct work_struct *work);
150
151 static DEFINE_SPINLOCK(p9_poll_lock);
152 static LIST_HEAD(p9_poll_pending_list);
153 static DECLARE_WORK(p9_poll_work, p9_poll_workfn);
154
155 static unsigned int p9_ipport_resv_min = P9_DEF_MIN_RESVPORT;
156 static unsigned int p9_ipport_resv_max = P9_DEF_MAX_RESVPORT;
157
p9_mux_poll_stop(struct p9_conn * m)158 static void p9_mux_poll_stop(struct p9_conn *m)
159 {
160 unsigned long flags;
161 int i;
162
163 for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) {
164 struct p9_poll_wait *pwait = &m->poll_wait[i];
165
166 if (pwait->wait_addr) {
167 remove_wait_queue(pwait->wait_addr, &pwait->wait);
168 pwait->wait_addr = NULL;
169 }
170 }
171
172 spin_lock_irqsave(&p9_poll_lock, flags);
173 list_del_init(&m->poll_pending_link);
174 spin_unlock_irqrestore(&p9_poll_lock, flags);
175
176 flush_work(&p9_poll_work);
177 }
178
179 /**
180 * p9_conn_cancel - cancel all pending requests with error
181 * @m: mux data
182 * @err: error code
183 *
184 */
185
p9_conn_cancel(struct p9_conn * m,int err)186 static void p9_conn_cancel(struct p9_conn *m, int err)
187 {
188 struct p9_req_t *req, *rtmp;
189 LIST_HEAD(cancel_list);
190
191 p9_debug(P9_DEBUG_ERROR, "mux %p err %d\n", m, err);
192
193 spin_lock(&m->req_lock);
194
195 if (m->err) {
196 spin_unlock(&m->req_lock);
197 return;
198 }
199
200 m->err = err;
201
202 list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) {
203 list_move(&req->req_list, &cancel_list);
204 WRITE_ONCE(req->status, REQ_STATUS_ERROR);
205 }
206 list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) {
207 list_move(&req->req_list, &cancel_list);
208 WRITE_ONCE(req->status, REQ_STATUS_ERROR);
209 }
210
211 spin_unlock(&m->req_lock);
212
213 list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) {
214 p9_debug(P9_DEBUG_ERROR, "call back req %p\n", req);
215 list_del(&req->req_list);
216 if (!req->t_err)
217 req->t_err = err;
218 p9_client_cb(m->client, req, REQ_STATUS_ERROR);
219 }
220 }
221
222 static __poll_t
p9_fd_poll(struct p9_client * client,struct poll_table_struct * pt,int * err)223 p9_fd_poll(struct p9_client *client, struct poll_table_struct *pt, int *err)
224 {
225 __poll_t ret;
226 struct p9_trans_fd *ts = NULL;
227
228 if (client && client->status == Connected)
229 ts = client->trans;
230
231 if (!ts) {
232 if (err)
233 *err = -EREMOTEIO;
234 return EPOLLERR;
235 }
236
237 ret = vfs_poll(ts->rd, pt);
238 if (ts->rd != ts->wr)
239 ret = (ret & ~EPOLLOUT) | (vfs_poll(ts->wr, pt) & ~EPOLLIN);
240 return ret;
241 }
242
243 /**
244 * p9_fd_read- read from a fd
245 * @client: client instance
246 * @v: buffer to receive data into
247 * @len: size of receive buffer
248 *
249 */
250
p9_fd_read(struct p9_client * client,void * v,int len)251 static int p9_fd_read(struct p9_client *client, void *v, int len)
252 {
253 int ret;
254 struct p9_trans_fd *ts = NULL;
255 loff_t pos;
256
257 if (client && client->status != Disconnected)
258 ts = client->trans;
259
260 if (!ts)
261 return -EREMOTEIO;
262
263 if (!(ts->rd->f_flags & O_NONBLOCK))
264 p9_debug(P9_DEBUG_ERROR, "blocking read ...\n");
265
266 pos = ts->rd->f_pos;
267 ret = kernel_read(ts->rd, v, len, &pos);
268 if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
269 client->status = Disconnected;
270 return ret;
271 }
272
273 /**
274 * p9_read_work - called when there is some data to be read from a transport
275 * @work: container of work to be done
276 *
277 */
278
p9_read_work(struct work_struct * work)279 static void p9_read_work(struct work_struct *work)
280 {
281 __poll_t n;
282 int err;
283 struct p9_conn *m;
284
285 m = container_of(work, struct p9_conn, rq);
286
287 if (m->err < 0)
288 return;
289
290 p9_debug(P9_DEBUG_TRANS, "start mux %p pos %zd\n", m, m->rc.offset);
291
292 if (!m->rc.sdata) {
293 m->rc.sdata = m->tmp_buf;
294 m->rc.offset = 0;
295 m->rc.capacity = P9_HDRSZ; /* start by reading header */
296 }
297
298 clear_bit(Rpending, &m->wsched);
299 p9_debug(P9_DEBUG_TRANS, "read mux %p pos %zd size: %zd = %zd\n",
300 m, m->rc.offset, m->rc.capacity,
301 m->rc.capacity - m->rc.offset);
302 err = p9_fd_read(m->client, m->rc.sdata + m->rc.offset,
303 m->rc.capacity - m->rc.offset);
304 p9_debug(P9_DEBUG_TRANS, "mux %p got %d bytes\n", m, err);
305 if (err == -EAGAIN)
306 goto end_clear;
307
308 if (err <= 0)
309 goto error;
310
311 m->rc.offset += err;
312
313 /* header read in */
314 if ((!m->rreq) && (m->rc.offset == m->rc.capacity)) {
315 p9_debug(P9_DEBUG_TRANS, "got new header\n");
316
317 /* Header size */
318 m->rc.size = P9_HDRSZ;
319 err = p9_parse_header(&m->rc, &m->rc.size, NULL, NULL, 0);
320 if (err) {
321 p9_debug(P9_DEBUG_ERROR,
322 "error parsing header: %d\n", err);
323 goto error;
324 }
325
326 p9_debug(P9_DEBUG_TRANS,
327 "mux %p pkt: size: %d bytes tag: %d\n",
328 m, m->rc.size, m->rc.tag);
329
330 m->rreq = p9_tag_lookup(m->client, m->rc.tag);
331 if (!m->rreq || (m->rreq->status != REQ_STATUS_SENT)) {
332 p9_debug(P9_DEBUG_ERROR, "Unexpected packet tag %d\n",
333 m->rc.tag);
334 err = -EIO;
335 goto error;
336 }
337
338 if (m->rc.size > m->rreq->rc.capacity) {
339 p9_debug(P9_DEBUG_ERROR,
340 "requested packet size too big: %d for tag %d with capacity %zd\n",
341 m->rc.size, m->rc.tag, m->rreq->rc.capacity);
342 err = -EIO;
343 goto error;
344 }
345
346 if (!m->rreq->rc.sdata) {
347 p9_debug(P9_DEBUG_ERROR,
348 "No recv fcall for tag %d (req %p), disconnecting!\n",
349 m->rc.tag, m->rreq);
350 p9_req_put(m->client, m->rreq);
351 m->rreq = NULL;
352 err = -EIO;
353 goto error;
354 }
355 m->rc.sdata = m->rreq->rc.sdata;
356 memcpy(m->rc.sdata, m->tmp_buf, m->rc.capacity);
357 m->rc.capacity = m->rc.size;
358 }
359
360 /* packet is read in
361 * not an else because some packets (like clunk) have no payload
362 */
363 if ((m->rreq) && (m->rc.offset == m->rc.capacity)) {
364 p9_debug(P9_DEBUG_TRANS, "got new packet\n");
365 m->rreq->rc.size = m->rc.offset;
366 spin_lock(&m->req_lock);
367 if (m->rreq->status == REQ_STATUS_SENT) {
368 list_del(&m->rreq->req_list);
369 p9_client_cb(m->client, m->rreq, REQ_STATUS_RCVD);
370 } else if (m->rreq->status == REQ_STATUS_FLSHD) {
371 /* Ignore replies associated with a cancelled request. */
372 p9_debug(P9_DEBUG_TRANS,
373 "Ignore replies associated with a cancelled request\n");
374 } else {
375 spin_unlock(&m->req_lock);
376 p9_debug(P9_DEBUG_ERROR,
377 "Request tag %d errored out while we were reading the reply\n",
378 m->rc.tag);
379 err = -EIO;
380 goto error;
381 }
382 spin_unlock(&m->req_lock);
383 m->rc.sdata = NULL;
384 m->rc.offset = 0;
385 m->rc.capacity = 0;
386 p9_req_put(m->client, m->rreq);
387 m->rreq = NULL;
388 }
389
390 end_clear:
391 clear_bit(Rworksched, &m->wsched);
392
393 if (!list_empty(&m->req_list)) {
394 if (test_and_clear_bit(Rpending, &m->wsched))
395 n = EPOLLIN;
396 else
397 n = p9_fd_poll(m->client, NULL, NULL);
398
399 if ((n & EPOLLIN) && !test_and_set_bit(Rworksched, &m->wsched)) {
400 p9_debug(P9_DEBUG_TRANS, "sched read work %p\n", m);
401 schedule_work(&m->rq);
402 }
403 }
404
405 return;
406 error:
407 p9_conn_cancel(m, err);
408 clear_bit(Rworksched, &m->wsched);
409 }
410
411 /**
412 * p9_fd_write - write to a socket
413 * @client: client instance
414 * @v: buffer to send data from
415 * @len: size of send buffer
416 *
417 */
418
p9_fd_write(struct p9_client * client,void * v,int len)419 static int p9_fd_write(struct p9_client *client, void *v, int len)
420 {
421 ssize_t ret;
422 struct p9_trans_fd *ts = NULL;
423
424 if (client && client->status != Disconnected)
425 ts = client->trans;
426
427 if (!ts)
428 return -EREMOTEIO;
429
430 if (!(ts->wr->f_flags & O_NONBLOCK))
431 p9_debug(P9_DEBUG_ERROR, "blocking write ...\n");
432
433 ret = kernel_write(ts->wr, v, len, &ts->wr->f_pos);
434 if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
435 client->status = Disconnected;
436 return ret;
437 }
438
439 /**
440 * p9_write_work - called when a transport can send some data
441 * @work: container for work to be done
442 *
443 */
444
p9_write_work(struct work_struct * work)445 static void p9_write_work(struct work_struct *work)
446 {
447 __poll_t n;
448 int err;
449 struct p9_conn *m;
450 struct p9_req_t *req;
451
452 m = container_of(work, struct p9_conn, wq);
453
454 if (m->err < 0) {
455 clear_bit(Wworksched, &m->wsched);
456 return;
457 }
458
459 if (!m->wsize) {
460 spin_lock(&m->req_lock);
461 if (list_empty(&m->unsent_req_list)) {
462 clear_bit(Wworksched, &m->wsched);
463 spin_unlock(&m->req_lock);
464 return;
465 }
466
467 req = list_entry(m->unsent_req_list.next, struct p9_req_t,
468 req_list);
469 WRITE_ONCE(req->status, REQ_STATUS_SENT);
470 p9_debug(P9_DEBUG_TRANS, "move req %p\n", req);
471 list_move_tail(&req->req_list, &m->req_list);
472
473 m->wbuf = req->tc.sdata;
474 m->wsize = req->tc.size;
475 m->wpos = 0;
476 p9_req_get(req);
477 m->wreq = req;
478 spin_unlock(&m->req_lock);
479 }
480
481 p9_debug(P9_DEBUG_TRANS, "mux %p pos %d size %d\n",
482 m, m->wpos, m->wsize);
483 clear_bit(Wpending, &m->wsched);
484 err = p9_fd_write(m->client, m->wbuf + m->wpos, m->wsize - m->wpos);
485 p9_debug(P9_DEBUG_TRANS, "mux %p sent %d bytes\n", m, err);
486 if (err == -EAGAIN)
487 goto end_clear;
488
489
490 if (err < 0)
491 goto error;
492 else if (err == 0) {
493 err = -EREMOTEIO;
494 goto error;
495 }
496
497 m->wpos += err;
498 if (m->wpos == m->wsize) {
499 m->wpos = m->wsize = 0;
500 p9_req_put(m->client, m->wreq);
501 m->wreq = NULL;
502 }
503
504 end_clear:
505 clear_bit(Wworksched, &m->wsched);
506
507 if (m->wsize || !list_empty(&m->unsent_req_list)) {
508 if (test_and_clear_bit(Wpending, &m->wsched))
509 n = EPOLLOUT;
510 else
511 n = p9_fd_poll(m->client, NULL, NULL);
512
513 if ((n & EPOLLOUT) &&
514 !test_and_set_bit(Wworksched, &m->wsched)) {
515 p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m);
516 schedule_work(&m->wq);
517 }
518 }
519
520 return;
521
522 error:
523 p9_conn_cancel(m, err);
524 clear_bit(Wworksched, &m->wsched);
525 }
526
p9_pollwake(wait_queue_entry_t * wait,unsigned int mode,int sync,void * key)527 static int p9_pollwake(wait_queue_entry_t *wait, unsigned int mode, int sync, void *key)
528 {
529 struct p9_poll_wait *pwait =
530 container_of(wait, struct p9_poll_wait, wait);
531 struct p9_conn *m = pwait->conn;
532 unsigned long flags;
533
534 spin_lock_irqsave(&p9_poll_lock, flags);
535 if (list_empty(&m->poll_pending_link))
536 list_add_tail(&m->poll_pending_link, &p9_poll_pending_list);
537 spin_unlock_irqrestore(&p9_poll_lock, flags);
538
539 schedule_work(&p9_poll_work);
540 return 1;
541 }
542
543 /**
544 * p9_pollwait - add poll task to the wait queue
545 * @filp: file pointer being polled
546 * @wait_address: wait_q to block on
547 * @p: poll state
548 *
549 * called by files poll operation to add v9fs-poll task to files wait queue
550 */
551
552 static void
p9_pollwait(struct file * filp,wait_queue_head_t * wait_address,poll_table * p)553 p9_pollwait(struct file *filp, wait_queue_head_t *wait_address, poll_table *p)
554 {
555 struct p9_conn *m = container_of(p, struct p9_conn, pt);
556 struct p9_poll_wait *pwait = NULL;
557 int i;
558
559 for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) {
560 if (m->poll_wait[i].wait_addr == NULL) {
561 pwait = &m->poll_wait[i];
562 break;
563 }
564 }
565
566 if (!pwait) {
567 p9_debug(P9_DEBUG_ERROR, "not enough wait_address slots\n");
568 return;
569 }
570
571 pwait->conn = m;
572 pwait->wait_addr = wait_address;
573 init_waitqueue_func_entry(&pwait->wait, p9_pollwake);
574 add_wait_queue(wait_address, &pwait->wait);
575 }
576
577 /**
578 * p9_conn_create - initialize the per-session mux data
579 * @client: client instance
580 *
581 * Note: Creates the polling task if this is the first session.
582 */
583
p9_conn_create(struct p9_client * client)584 static void p9_conn_create(struct p9_client *client)
585 {
586 __poll_t n;
587 struct p9_trans_fd *ts = client->trans;
588 struct p9_conn *m = &ts->conn;
589
590 p9_debug(P9_DEBUG_TRANS, "client %p msize %d\n", client, client->msize);
591
592 INIT_LIST_HEAD(&m->mux_list);
593 m->client = client;
594
595 spin_lock_init(&m->req_lock);
596 INIT_LIST_HEAD(&m->req_list);
597 INIT_LIST_HEAD(&m->unsent_req_list);
598 INIT_WORK(&m->rq, p9_read_work);
599 INIT_WORK(&m->wq, p9_write_work);
600 INIT_LIST_HEAD(&m->poll_pending_link);
601 init_poll_funcptr(&m->pt, p9_pollwait);
602
603 n = p9_fd_poll(client, &m->pt, NULL);
604 if (n & EPOLLIN) {
605 p9_debug(P9_DEBUG_TRANS, "mux %p can read\n", m);
606 set_bit(Rpending, &m->wsched);
607 }
608
609 if (n & EPOLLOUT) {
610 p9_debug(P9_DEBUG_TRANS, "mux %p can write\n", m);
611 set_bit(Wpending, &m->wsched);
612 }
613 }
614
615 /**
616 * p9_poll_mux - polls a mux and schedules read or write works if necessary
617 * @m: connection to poll
618 *
619 */
620
p9_poll_mux(struct p9_conn * m)621 static void p9_poll_mux(struct p9_conn *m)
622 {
623 __poll_t n;
624 int err = -ECONNRESET;
625
626 if (m->err < 0)
627 return;
628
629 n = p9_fd_poll(m->client, NULL, &err);
630 if (n & (EPOLLERR | EPOLLHUP | EPOLLNVAL)) {
631 p9_debug(P9_DEBUG_TRANS, "error mux %p err %d\n", m, n);
632 p9_conn_cancel(m, err);
633 }
634
635 if (n & EPOLLIN) {
636 set_bit(Rpending, &m->wsched);
637 p9_debug(P9_DEBUG_TRANS, "mux %p can read\n", m);
638 if (!test_and_set_bit(Rworksched, &m->wsched)) {
639 p9_debug(P9_DEBUG_TRANS, "sched read work %p\n", m);
640 schedule_work(&m->rq);
641 }
642 }
643
644 if (n & EPOLLOUT) {
645 set_bit(Wpending, &m->wsched);
646 p9_debug(P9_DEBUG_TRANS, "mux %p can write\n", m);
647 if ((m->wsize || !list_empty(&m->unsent_req_list)) &&
648 !test_and_set_bit(Wworksched, &m->wsched)) {
649 p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m);
650 schedule_work(&m->wq);
651 }
652 }
653 }
654
655 /**
656 * p9_fd_request - send 9P request
657 * The function can sleep until the request is scheduled for sending.
658 * The function can be interrupted. Return from the function is not
659 * a guarantee that the request is sent successfully.
660 *
661 * @client: client instance
662 * @req: request to be sent
663 *
664 */
665
p9_fd_request(struct p9_client * client,struct p9_req_t * req)666 static int p9_fd_request(struct p9_client *client, struct p9_req_t *req)
667 {
668 __poll_t n;
669 struct p9_trans_fd *ts = client->trans;
670 struct p9_conn *m = &ts->conn;
671
672 p9_debug(P9_DEBUG_TRANS, "mux %p task %p tcall %p id %d\n",
673 m, current, &req->tc, req->tc.id);
674 if (m->err < 0)
675 return m->err;
676
677 spin_lock(&m->req_lock);
678 WRITE_ONCE(req->status, REQ_STATUS_UNSENT);
679 list_add_tail(&req->req_list, &m->unsent_req_list);
680 spin_unlock(&m->req_lock);
681
682 if (test_and_clear_bit(Wpending, &m->wsched))
683 n = EPOLLOUT;
684 else
685 n = p9_fd_poll(m->client, NULL, NULL);
686
687 if (n & EPOLLOUT && !test_and_set_bit(Wworksched, &m->wsched))
688 schedule_work(&m->wq);
689
690 return 0;
691 }
692
p9_fd_cancel(struct p9_client * client,struct p9_req_t * req)693 static int p9_fd_cancel(struct p9_client *client, struct p9_req_t *req)
694 {
695 struct p9_trans_fd *ts = client->trans;
696 struct p9_conn *m = &ts->conn;
697 int ret = 1;
698
699 p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req);
700
701 spin_lock(&m->req_lock);
702
703 if (req->status == REQ_STATUS_UNSENT) {
704 list_del(&req->req_list);
705 WRITE_ONCE(req->status, REQ_STATUS_FLSHD);
706 p9_req_put(client, req);
707 ret = 0;
708 }
709 spin_unlock(&m->req_lock);
710
711 return ret;
712 }
713
p9_fd_cancelled(struct p9_client * client,struct p9_req_t * req)714 static int p9_fd_cancelled(struct p9_client *client, struct p9_req_t *req)
715 {
716 struct p9_trans_fd *ts = client->trans;
717 struct p9_conn *m = &ts->conn;
718
719 p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req);
720
721 spin_lock(&m->req_lock);
722 /* Ignore cancelled request if message has been received
723 * before lock.
724 */
725 if (req->status == REQ_STATUS_RCVD) {
726 spin_unlock(&m->req_lock);
727 return 0;
728 }
729
730 /* we haven't received a response for oldreq,
731 * remove it from the list.
732 */
733 list_del(&req->req_list);
734 WRITE_ONCE(req->status, REQ_STATUS_FLSHD);
735 spin_unlock(&m->req_lock);
736
737 p9_req_put(client, req);
738
739 return 0;
740 }
741
p9_fd_show_options(struct seq_file * m,struct p9_client * clnt)742 static int p9_fd_show_options(struct seq_file *m, struct p9_client *clnt)
743 {
744 if (clnt->trans_mod == &p9_tcp_trans) {
745 if (clnt->trans_opts.tcp.port != P9_PORT)
746 seq_printf(m, ",port=%u", clnt->trans_opts.tcp.port);
747 } else if (clnt->trans_mod == &p9_fd_trans) {
748 if (clnt->trans_opts.fd.rfd != ~0)
749 seq_printf(m, ",rfd=%u", clnt->trans_opts.fd.rfd);
750 if (clnt->trans_opts.fd.wfd != ~0)
751 seq_printf(m, ",wfd=%u", clnt->trans_opts.fd.wfd);
752 }
753 return 0;
754 }
755
756 /**
757 * parse_opts - parse mount options into p9_fd_opts structure
758 * @params: options string passed from mount
759 * @opts: fd transport-specific structure to parse options into
760 *
761 * Returns 0 upon success, -ERRNO upon failure
762 */
763
parse_opts(char * params,struct p9_fd_opts * opts)764 static int parse_opts(char *params, struct p9_fd_opts *opts)
765 {
766 char *p;
767 substring_t args[MAX_OPT_ARGS];
768 int option;
769 char *options, *tmp_options;
770
771 opts->port = P9_PORT;
772 opts->rfd = ~0;
773 opts->wfd = ~0;
774 opts->privport = false;
775
776 if (!params)
777 return 0;
778
779 tmp_options = kstrdup(params, GFP_KERNEL);
780 if (!tmp_options) {
781 p9_debug(P9_DEBUG_ERROR,
782 "failed to allocate copy of option string\n");
783 return -ENOMEM;
784 }
785 options = tmp_options;
786
787 while ((p = strsep(&options, ",")) != NULL) {
788 int token;
789 int r;
790 if (!*p)
791 continue;
792 token = match_token(p, tokens, args);
793 if ((token != Opt_err) && (token != Opt_privport)) {
794 r = match_int(&args[0], &option);
795 if (r < 0) {
796 p9_debug(P9_DEBUG_ERROR,
797 "integer field, but no integer?\n");
798 continue;
799 }
800 }
801 switch (token) {
802 case Opt_port:
803 opts->port = option;
804 break;
805 case Opt_rfdno:
806 opts->rfd = option;
807 break;
808 case Opt_wfdno:
809 opts->wfd = option;
810 break;
811 case Opt_privport:
812 opts->privport = true;
813 break;
814 default:
815 continue;
816 }
817 }
818
819 kfree(tmp_options);
820 return 0;
821 }
822
p9_fd_open(struct p9_client * client,int rfd,int wfd)823 static int p9_fd_open(struct p9_client *client, int rfd, int wfd)
824 {
825 struct p9_trans_fd *ts = kzalloc(sizeof(struct p9_trans_fd),
826 GFP_KERNEL);
827 if (!ts)
828 return -ENOMEM;
829
830 ts->rd = fget(rfd);
831 if (!ts->rd)
832 goto out_free_ts;
833 if (!(ts->rd->f_mode & FMODE_READ))
834 goto out_put_rd;
835 /* prevent workers from hanging on IO when fd is a pipe */
836 ts->rd->f_flags |= O_NONBLOCK;
837 ts->wr = fget(wfd);
838 if (!ts->wr)
839 goto out_put_rd;
840 if (!(ts->wr->f_mode & FMODE_WRITE))
841 goto out_put_wr;
842 ts->wr->f_flags |= O_NONBLOCK;
843
844 client->trans = ts;
845 client->status = Connected;
846
847 return 0;
848
849 out_put_wr:
850 fput(ts->wr);
851 out_put_rd:
852 fput(ts->rd);
853 out_free_ts:
854 kfree(ts);
855 return -EIO;
856 }
857
p9_socket_open(struct p9_client * client,struct socket * csocket)858 static int p9_socket_open(struct p9_client *client, struct socket *csocket)
859 {
860 struct p9_trans_fd *p;
861 struct file *file;
862
863 p = kzalloc(sizeof(struct p9_trans_fd), GFP_KERNEL);
864 if (!p) {
865 sock_release(csocket);
866 return -ENOMEM;
867 }
868
869 csocket->sk->sk_allocation = GFP_NOIO;
870 csocket->sk->sk_use_task_frag = false;
871 file = sock_alloc_file(csocket, 0, NULL);
872 if (IS_ERR(file)) {
873 pr_err("%s (%d): failed to map fd\n",
874 __func__, task_pid_nr(current));
875 kfree(p);
876 return PTR_ERR(file);
877 }
878
879 get_file(file);
880 p->wr = p->rd = file;
881 client->trans = p;
882 client->status = Connected;
883
884 p->rd->f_flags |= O_NONBLOCK;
885
886 p9_conn_create(client);
887 return 0;
888 }
889
890 /**
891 * p9_conn_destroy - cancels all pending requests of mux
892 * @m: mux to destroy
893 *
894 */
895
p9_conn_destroy(struct p9_conn * m)896 static void p9_conn_destroy(struct p9_conn *m)
897 {
898 p9_debug(P9_DEBUG_TRANS, "mux %p prev %p next %p\n",
899 m, m->mux_list.prev, m->mux_list.next);
900
901 p9_mux_poll_stop(m);
902 cancel_work_sync(&m->rq);
903 if (m->rreq) {
904 p9_req_put(m->client, m->rreq);
905 m->rreq = NULL;
906 }
907 cancel_work_sync(&m->wq);
908 if (m->wreq) {
909 p9_req_put(m->client, m->wreq);
910 m->wreq = NULL;
911 }
912
913 p9_conn_cancel(m, -ECONNRESET);
914
915 m->client = NULL;
916 }
917
918 /**
919 * p9_fd_close - shutdown file descriptor transport
920 * @client: client instance
921 *
922 */
923
p9_fd_close(struct p9_client * client)924 static void p9_fd_close(struct p9_client *client)
925 {
926 struct p9_trans_fd *ts;
927
928 if (!client)
929 return;
930
931 ts = client->trans;
932 if (!ts)
933 return;
934
935 client->status = Disconnected;
936
937 p9_conn_destroy(&ts->conn);
938
939 if (ts->rd)
940 fput(ts->rd);
941 if (ts->wr)
942 fput(ts->wr);
943
944 kfree(ts);
945 }
946
947 /*
948 * stolen from NFS - maybe should be made a generic function?
949 */
valid_ipaddr4(const char * buf)950 static inline int valid_ipaddr4(const char *buf)
951 {
952 int rc, count, in[4];
953
954 rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]);
955 if (rc != 4)
956 return -EINVAL;
957 for (count = 0; count < 4; count++) {
958 if (in[count] > 255)
959 return -EINVAL;
960 }
961 return 0;
962 }
963
p9_bind_privport(struct socket * sock)964 static int p9_bind_privport(struct socket *sock)
965 {
966 struct sockaddr_in cl;
967 int port, err = -EINVAL;
968
969 memset(&cl, 0, sizeof(cl));
970 cl.sin_family = AF_INET;
971 cl.sin_addr.s_addr = htonl(INADDR_ANY);
972 for (port = p9_ipport_resv_max; port >= p9_ipport_resv_min; port--) {
973 cl.sin_port = htons((ushort)port);
974 err = kernel_bind(sock, (struct sockaddr *)&cl, sizeof(cl));
975 if (err != -EADDRINUSE)
976 break;
977 }
978 return err;
979 }
980
981
982 static int
p9_fd_create_tcp(struct p9_client * client,const char * addr,char * args)983 p9_fd_create_tcp(struct p9_client *client, const char *addr, char *args)
984 {
985 int err;
986 struct socket *csocket;
987 struct sockaddr_in sin_server;
988 struct p9_fd_opts opts;
989
990 err = parse_opts(args, &opts);
991 if (err < 0)
992 return err;
993
994 if (addr == NULL || valid_ipaddr4(addr) < 0)
995 return -EINVAL;
996
997 csocket = NULL;
998
999 client->trans_opts.tcp.port = opts.port;
1000 client->trans_opts.tcp.privport = opts.privport;
1001 sin_server.sin_family = AF_INET;
1002 sin_server.sin_addr.s_addr = in_aton(addr);
1003 sin_server.sin_port = htons(opts.port);
1004 err = __sock_create(current->nsproxy->net_ns, PF_INET,
1005 SOCK_STREAM, IPPROTO_TCP, &csocket, 1);
1006 if (err) {
1007 pr_err("%s (%d): problem creating socket\n",
1008 __func__, task_pid_nr(current));
1009 return err;
1010 }
1011
1012 if (opts.privport) {
1013 err = p9_bind_privport(csocket);
1014 if (err < 0) {
1015 pr_err("%s (%d): problem binding to privport\n",
1016 __func__, task_pid_nr(current));
1017 sock_release(csocket);
1018 return err;
1019 }
1020 }
1021
1022 err = READ_ONCE(csocket->ops)->connect(csocket,
1023 (struct sockaddr *)&sin_server,
1024 sizeof(struct sockaddr_in), 0);
1025 if (err < 0) {
1026 pr_err("%s (%d): problem connecting socket to %s\n",
1027 __func__, task_pid_nr(current), addr);
1028 sock_release(csocket);
1029 return err;
1030 }
1031
1032 return p9_socket_open(client, csocket);
1033 }
1034
1035 static int
p9_fd_create_unix(struct p9_client * client,const char * addr,char * args)1036 p9_fd_create_unix(struct p9_client *client, const char *addr, char *args)
1037 {
1038 int err;
1039 struct socket *csocket;
1040 struct sockaddr_un sun_server;
1041
1042 csocket = NULL;
1043
1044 if (!addr || !strlen(addr))
1045 return -EINVAL;
1046
1047 if (strlen(addr) >= UNIX_PATH_MAX) {
1048 pr_err("%s (%d): address too long: %s\n",
1049 __func__, task_pid_nr(current), addr);
1050 return -ENAMETOOLONG;
1051 }
1052
1053 sun_server.sun_family = PF_UNIX;
1054 strcpy(sun_server.sun_path, addr);
1055 err = __sock_create(current->nsproxy->net_ns, PF_UNIX,
1056 SOCK_STREAM, 0, &csocket, 1);
1057 if (err < 0) {
1058 pr_err("%s (%d): problem creating socket\n",
1059 __func__, task_pid_nr(current));
1060
1061 return err;
1062 }
1063 err = READ_ONCE(csocket->ops)->connect(csocket, (struct sockaddr *)&sun_server,
1064 sizeof(struct sockaddr_un) - 1, 0);
1065 if (err < 0) {
1066 pr_err("%s (%d): problem connecting socket: %s: %d\n",
1067 __func__, task_pid_nr(current), addr, err);
1068 sock_release(csocket);
1069 return err;
1070 }
1071
1072 return p9_socket_open(client, csocket);
1073 }
1074
1075 static int
p9_fd_create(struct p9_client * client,const char * addr,char * args)1076 p9_fd_create(struct p9_client *client, const char *addr, char *args)
1077 {
1078 int err;
1079 struct p9_fd_opts opts;
1080
1081 err = parse_opts(args, &opts);
1082 if (err < 0)
1083 return err;
1084 client->trans_opts.fd.rfd = opts.rfd;
1085 client->trans_opts.fd.wfd = opts.wfd;
1086
1087 if (opts.rfd == ~0 || opts.wfd == ~0) {
1088 pr_err("Insufficient options for proto=fd\n");
1089 return -ENOPROTOOPT;
1090 }
1091
1092 err = p9_fd_open(client, opts.rfd, opts.wfd);
1093 if (err < 0)
1094 return err;
1095
1096 p9_conn_create(client);
1097
1098 return 0;
1099 }
1100
1101 static struct p9_trans_module p9_tcp_trans = {
1102 .name = "tcp",
1103 .maxsize = MAX_SOCK_BUF,
1104 .pooled_rbuffers = false,
1105 .def = 0,
1106 .create = p9_fd_create_tcp,
1107 .close = p9_fd_close,
1108 .request = p9_fd_request,
1109 .cancel = p9_fd_cancel,
1110 .cancelled = p9_fd_cancelled,
1111 .show_options = p9_fd_show_options,
1112 .owner = THIS_MODULE,
1113 };
1114 MODULE_ALIAS_9P("tcp");
1115
1116 static struct p9_trans_module p9_unix_trans = {
1117 .name = "unix",
1118 .maxsize = MAX_SOCK_BUF,
1119 .def = 0,
1120 .create = p9_fd_create_unix,
1121 .close = p9_fd_close,
1122 .request = p9_fd_request,
1123 .cancel = p9_fd_cancel,
1124 .cancelled = p9_fd_cancelled,
1125 .show_options = p9_fd_show_options,
1126 .owner = THIS_MODULE,
1127 };
1128 MODULE_ALIAS_9P("unix");
1129
1130 static struct p9_trans_module p9_fd_trans = {
1131 .name = "fd",
1132 .maxsize = MAX_SOCK_BUF,
1133 .def = 0,
1134 .create = p9_fd_create,
1135 .close = p9_fd_close,
1136 .request = p9_fd_request,
1137 .cancel = p9_fd_cancel,
1138 .cancelled = p9_fd_cancelled,
1139 .show_options = p9_fd_show_options,
1140 .owner = THIS_MODULE,
1141 };
1142 MODULE_ALIAS_9P("fd");
1143
1144 /**
1145 * p9_poll_workfn - poll worker thread
1146 * @work: work queue
1147 *
1148 * polls all v9fs transports for new events and queues the appropriate
1149 * work to the work queue
1150 *
1151 */
1152
p9_poll_workfn(struct work_struct * work)1153 static void p9_poll_workfn(struct work_struct *work)
1154 {
1155 unsigned long flags;
1156
1157 p9_debug(P9_DEBUG_TRANS, "start %p\n", current);
1158
1159 spin_lock_irqsave(&p9_poll_lock, flags);
1160 while (!list_empty(&p9_poll_pending_list)) {
1161 struct p9_conn *conn = list_first_entry(&p9_poll_pending_list,
1162 struct p9_conn,
1163 poll_pending_link);
1164 list_del_init(&conn->poll_pending_link);
1165 spin_unlock_irqrestore(&p9_poll_lock, flags);
1166
1167 p9_poll_mux(conn);
1168
1169 spin_lock_irqsave(&p9_poll_lock, flags);
1170 }
1171 spin_unlock_irqrestore(&p9_poll_lock, flags);
1172
1173 p9_debug(P9_DEBUG_TRANS, "finish\n");
1174 }
1175
p9_trans_fd_init(void)1176 static int __init p9_trans_fd_init(void)
1177 {
1178 v9fs_register_trans(&p9_tcp_trans);
1179 v9fs_register_trans(&p9_unix_trans);
1180 v9fs_register_trans(&p9_fd_trans);
1181
1182 return 0;
1183 }
1184
p9_trans_fd_exit(void)1185 static void __exit p9_trans_fd_exit(void)
1186 {
1187 flush_work(&p9_poll_work);
1188 v9fs_unregister_trans(&p9_tcp_trans);
1189 v9fs_unregister_trans(&p9_unix_trans);
1190 v9fs_unregister_trans(&p9_fd_trans);
1191 }
1192
1193 module_init(p9_trans_fd_init);
1194 module_exit(p9_trans_fd_exit);
1195
1196 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
1197 MODULE_DESCRIPTION("Filedescriptor Transport for 9P");
1198 MODULE_LICENSE("GPL");
1199
