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 * @tmp_buf: temporary buffer to read in header
99 * @rc: temporary fcall for reading current frame
100 * @wpos: write position for current frame
101 * @wsize: amount of data to write for current frame
102 * @wbuf: current write buffer
103 * @poll_pending_link: pending links to be polled per conn
104 * @poll_wait: array of wait_q's for various worker threads
105 * @pt: poll state
106 * @rq: current read work
107 * @wq: current write work
108 * @wsched: ????
109 *
110 */
111
112 struct p9_conn {
113 struct list_head mux_list;
114 struct p9_client *client;
115 int err;
116 spinlock_t req_lock;
117 struct list_head req_list;
118 struct list_head unsent_req_list;
119 struct p9_req_t *rreq;
120 struct p9_req_t *wreq;
121 char tmp_buf[P9_HDRSZ];
122 struct p9_fcall rc;
123 int wpos;
124 int wsize;
125 char *wbuf;
126 struct list_head poll_pending_link;
127 struct p9_poll_wait poll_wait[MAXPOLLWADDR];
128 poll_table pt;
129 struct work_struct rq;
130 struct work_struct wq;
131 unsigned long wsched;
132 };
133
134 /**
135 * struct p9_trans_fd - transport state
136 * @rd: reference to file to read from
137 * @wr: reference of file to write to
138 * @conn: connection state reference
139 *
140 */
141
142 struct p9_trans_fd {
143 struct file *rd;
144 struct file *wr;
145 struct p9_conn conn;
146 };
147
148 static void p9_poll_workfn(struct work_struct *work);
149
150 static DEFINE_SPINLOCK(p9_poll_lock);
151 static LIST_HEAD(p9_poll_pending_list);
152 static DECLARE_WORK(p9_poll_work, p9_poll_workfn);
153
154 static unsigned int p9_ipport_resv_min = P9_DEF_MIN_RESVPORT;
155 static unsigned int p9_ipport_resv_max = P9_DEF_MAX_RESVPORT;
156
p9_mux_poll_stop(struct p9_conn * m)157 static void p9_mux_poll_stop(struct p9_conn *m)
158 {
159 unsigned long flags;
160 int i;
161
162 for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) {
163 struct p9_poll_wait *pwait = &m->poll_wait[i];
164
165 if (pwait->wait_addr) {
166 remove_wait_queue(pwait->wait_addr, &pwait->wait);
167 pwait->wait_addr = NULL;
168 }
169 }
170
171 spin_lock_irqsave(&p9_poll_lock, flags);
172 list_del_init(&m->poll_pending_link);
173 spin_unlock_irqrestore(&p9_poll_lock, flags);
174
175 flush_work(&p9_poll_work);
176 }
177
178 /**
179 * p9_conn_cancel - cancel all pending requests with error
180 * @m: mux data
181 * @err: error code
182 *
183 */
184
p9_conn_cancel(struct p9_conn * m,int err)185 static void p9_conn_cancel(struct p9_conn *m, int err)
186 {
187 struct p9_req_t *req, *rtmp;
188 LIST_HEAD(cancel_list);
189
190 p9_debug(P9_DEBUG_ERROR, "mux %p err %d\n", m, err);
191
192 spin_lock(&m->req_lock);
193
194 if (m->err) {
195 spin_unlock(&m->req_lock);
196 return;
197 }
198
199 m->err = err;
200
201 list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) {
202 list_move(&req->req_list, &cancel_list);
203 WRITE_ONCE(req->status, REQ_STATUS_ERROR);
204 }
205 list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) {
206 list_move(&req->req_list, &cancel_list);
207 WRITE_ONCE(req->status, REQ_STATUS_ERROR);
208 }
209
210 spin_unlock(&m->req_lock);
211
212 list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) {
213 p9_debug(P9_DEBUG_ERROR, "call back req %p\n", req);
214 list_del(&req->req_list);
215 if (!req->t_err)
216 req->t_err = err;
217 p9_client_cb(m->client, req, REQ_STATUS_ERROR);
218 }
219 }
220
221 static __poll_t
p9_fd_poll(struct p9_client * client,struct poll_table_struct * pt,int * err)222 p9_fd_poll(struct p9_client *client, struct poll_table_struct *pt, int *err)
223 {
224 __poll_t ret;
225 struct p9_trans_fd *ts = NULL;
226
227 if (client && client->status == Connected)
228 ts = client->trans;
229
230 if (!ts) {
231 if (err)
232 *err = -EREMOTEIO;
233 return EPOLLERR;
234 }
235
236 ret = vfs_poll(ts->rd, pt);
237 if (ts->rd != ts->wr)
238 ret = (ret & ~EPOLLOUT) | (vfs_poll(ts->wr, pt) & ~EPOLLIN);
239 return ret;
240 }
241
242 /**
243 * p9_fd_read- read from a fd
244 * @client: client instance
245 * @v: buffer to receive data into
246 * @len: size of receive buffer
247 *
248 */
249
p9_fd_read(struct p9_client * client,void * v,int len)250 static int p9_fd_read(struct p9_client *client, void *v, int len)
251 {
252 int ret;
253 struct p9_trans_fd *ts = NULL;
254 loff_t pos;
255
256 if (client && client->status != Disconnected)
257 ts = client->trans;
258
259 if (!ts)
260 return -EREMOTEIO;
261
262 if (!(ts->rd->f_flags & O_NONBLOCK))
263 p9_debug(P9_DEBUG_ERROR, "blocking read ...\n");
264
265 pos = ts->rd->f_pos;
266 ret = kernel_read(ts->rd, v, len, &pos);
267 if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
268 client->status = Disconnected;
269 return ret;
270 }
271
272 /**
273 * p9_read_work - called when there is some data to be read from a transport
274 * @work: container of work to be done
275 *
276 */
277
p9_read_work(struct work_struct * work)278 static void p9_read_work(struct work_struct *work)
279 {
280 __poll_t n;
281 int err;
282 struct p9_conn *m;
283
284 m = container_of(work, struct p9_conn, rq);
285
286 if (m->err < 0)
287 return;
288
289 p9_debug(P9_DEBUG_TRANS, "start mux %p pos %zd\n", m, m->rc.offset);
290
291 if (!m->rc.sdata) {
292 m->rc.sdata = m->tmp_buf;
293 m->rc.offset = 0;
294 m->rc.capacity = P9_HDRSZ; /* start by reading header */
295 }
296
297 clear_bit(Rpending, &m->wsched);
298 p9_debug(P9_DEBUG_TRANS, "read mux %p pos %zd size: %zd = %zd\n",
299 m, m->rc.offset, m->rc.capacity,
300 m->rc.capacity - m->rc.offset);
301 err = p9_fd_read(m->client, m->rc.sdata + m->rc.offset,
302 m->rc.capacity - m->rc.offset);
303 p9_debug(P9_DEBUG_TRANS, "mux %p got %d bytes\n", m, err);
304 if (err == -EAGAIN)
305 goto end_clear;
306
307 if (err <= 0)
308 goto error;
309
310 m->rc.offset += err;
311
312 /* header read in */
313 if ((!m->rreq) && (m->rc.offset == m->rc.capacity)) {
314 p9_debug(P9_DEBUG_TRANS, "got new header\n");
315
316 /* Header size */
317 m->rc.size = P9_HDRSZ;
318 err = p9_parse_header(&m->rc, &m->rc.size, NULL, NULL, 0);
319 if (err) {
320 p9_debug(P9_DEBUG_ERROR,
321 "error parsing header: %d\n", err);
322 goto error;
323 }
324
325 p9_debug(P9_DEBUG_TRANS,
326 "mux %p pkt: size: %d bytes tag: %d\n",
327 m, m->rc.size, m->rc.tag);
328
329 m->rreq = p9_tag_lookup(m->client, m->rc.tag);
330 if (!m->rreq || (m->rreq->status != REQ_STATUS_SENT)) {
331 p9_debug(P9_DEBUG_ERROR, "Unexpected packet tag %d\n",
332 m->rc.tag);
333 err = -EIO;
334 goto error;
335 }
336
337 if (m->rc.size > m->rreq->rc.capacity) {
338 p9_debug(P9_DEBUG_ERROR,
339 "requested packet size too big: %d for tag %d with capacity %zd\n",
340 m->rc.size, m->rc.tag, m->rreq->rc.capacity);
341 err = -EIO;
342 goto error;
343 }
344
345 if (!m->rreq->rc.sdata) {
346 p9_debug(P9_DEBUG_ERROR,
347 "No recv fcall for tag %d (req %p), disconnecting!\n",
348 m->rc.tag, m->rreq);
349 p9_req_put(m->client, m->rreq);
350 m->rreq = NULL;
351 err = -EIO;
352 goto error;
353 }
354 m->rc.sdata = m->rreq->rc.sdata;
355 memcpy(m->rc.sdata, m->tmp_buf, m->rc.capacity);
356 m->rc.capacity = m->rc.size;
357 }
358
359 /* packet is read in
360 * not an else because some packets (like clunk) have no payload
361 */
362 if ((m->rreq) && (m->rc.offset == m->rc.capacity)) {
363 p9_debug(P9_DEBUG_TRANS, "got new packet\n");
364 m->rreq->rc.size = m->rc.offset;
365 spin_lock(&m->req_lock);
366 if (m->rreq->status == REQ_STATUS_SENT) {
367 list_del(&m->rreq->req_list);
368 p9_client_cb(m->client, m->rreq, REQ_STATUS_RCVD);
369 } else if (m->rreq->status == REQ_STATUS_FLSHD) {
370 /* Ignore replies associated with a cancelled request. */
371 p9_debug(P9_DEBUG_TRANS,
372 "Ignore replies associated with a cancelled request\n");
373 } else {
374 spin_unlock(&m->req_lock);
375 p9_debug(P9_DEBUG_ERROR,
376 "Request tag %d errored out while we were reading the reply\n",
377 m->rc.tag);
378 err = -EIO;
379 goto error;
380 }
381 spin_unlock(&m->req_lock);
382 m->rc.sdata = NULL;
383 m->rc.offset = 0;
384 m->rc.capacity = 0;
385 p9_req_put(m->client, m->rreq);
386 m->rreq = NULL;
387 }
388
389 end_clear:
390 clear_bit(Rworksched, &m->wsched);
391
392 if (!list_empty(&m->req_list)) {
393 if (test_and_clear_bit(Rpending, &m->wsched))
394 n = EPOLLIN;
395 else
396 n = p9_fd_poll(m->client, NULL, NULL);
397
398 if ((n & EPOLLIN) && !test_and_set_bit(Rworksched, &m->wsched)) {
399 p9_debug(P9_DEBUG_TRANS, "sched read work %p\n", m);
400 schedule_work(&m->rq);
401 }
402 }
403
404 return;
405 error:
406 p9_conn_cancel(m, err);
407 clear_bit(Rworksched, &m->wsched);
408 }
409
410 /**
411 * p9_fd_write - write to a socket
412 * @client: client instance
413 * @v: buffer to send data from
414 * @len: size of send buffer
415 *
416 */
417
p9_fd_write(struct p9_client * client,void * v,int len)418 static int p9_fd_write(struct p9_client *client, void *v, int len)
419 {
420 ssize_t ret;
421 struct p9_trans_fd *ts = NULL;
422
423 if (client && client->status != Disconnected)
424 ts = client->trans;
425
426 if (!ts)
427 return -EREMOTEIO;
428
429 if (!(ts->wr->f_flags & O_NONBLOCK))
430 p9_debug(P9_DEBUG_ERROR, "blocking write ...\n");
431
432 ret = kernel_write(ts->wr, v, len, &ts->wr->f_pos);
433 if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
434 client->status = Disconnected;
435 return ret;
436 }
437
438 /**
439 * p9_write_work - called when a transport can send some data
440 * @work: container for work to be done
441 *
442 */
443
p9_write_work(struct work_struct * work)444 static void p9_write_work(struct work_struct *work)
445 {
446 __poll_t n;
447 int err;
448 struct p9_conn *m;
449 struct p9_req_t *req;
450
451 m = container_of(work, struct p9_conn, wq);
452
453 if (m->err < 0) {
454 clear_bit(Wworksched, &m->wsched);
455 return;
456 }
457
458 if (!m->wsize) {
459 spin_lock(&m->req_lock);
460 if (list_empty(&m->unsent_req_list)) {
461 clear_bit(Wworksched, &m->wsched);
462 spin_unlock(&m->req_lock);
463 return;
464 }
465
466 req = list_entry(m->unsent_req_list.next, struct p9_req_t,
467 req_list);
468 WRITE_ONCE(req->status, REQ_STATUS_SENT);
469 p9_debug(P9_DEBUG_TRANS, "move req %p\n", req);
470 list_move_tail(&req->req_list, &m->req_list);
471
472 m->wbuf = req->tc.sdata;
473 m->wsize = req->tc.size;
474 m->wpos = 0;
475 p9_req_get(req);
476 m->wreq = req;
477 spin_unlock(&m->req_lock);
478 }
479
480 p9_debug(P9_DEBUG_TRANS, "mux %p pos %d size %d\n",
481 m, m->wpos, m->wsize);
482 clear_bit(Wpending, &m->wsched);
483 err = p9_fd_write(m->client, m->wbuf + m->wpos, m->wsize - m->wpos);
484 p9_debug(P9_DEBUG_TRANS, "mux %p sent %d bytes\n", m, err);
485 if (err == -EAGAIN)
486 goto end_clear;
487
488
489 if (err < 0)
490 goto error;
491 else if (err == 0) {
492 err = -EREMOTEIO;
493 goto error;
494 }
495
496 m->wpos += err;
497 if (m->wpos == m->wsize) {
498 m->wpos = m->wsize = 0;
499 p9_req_put(m->client, m->wreq);
500 m->wreq = NULL;
501 }
502
503 end_clear:
504 clear_bit(Wworksched, &m->wsched);
505
506 if (m->wsize || !list_empty(&m->unsent_req_list)) {
507 if (test_and_clear_bit(Wpending, &m->wsched))
508 n = EPOLLOUT;
509 else
510 n = p9_fd_poll(m->client, NULL, NULL);
511
512 if ((n & EPOLLOUT) &&
513 !test_and_set_bit(Wworksched, &m->wsched)) {
514 p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m);
515 schedule_work(&m->wq);
516 }
517 }
518
519 return;
520
521 error:
522 p9_conn_cancel(m, err);
523 clear_bit(Wworksched, &m->wsched);
524 }
525
p9_pollwake(wait_queue_entry_t * wait,unsigned int mode,int sync,void * key)526 static int p9_pollwake(wait_queue_entry_t *wait, unsigned int mode, int sync, void *key)
527 {
528 struct p9_poll_wait *pwait =
529 container_of(wait, struct p9_poll_wait, wait);
530 struct p9_conn *m = pwait->conn;
531 unsigned long flags;
532
533 spin_lock_irqsave(&p9_poll_lock, flags);
534 if (list_empty(&m->poll_pending_link))
535 list_add_tail(&m->poll_pending_link, &p9_poll_pending_list);
536 spin_unlock_irqrestore(&p9_poll_lock, flags);
537
538 schedule_work(&p9_poll_work);
539 return 1;
540 }
541
542 /**
543 * p9_pollwait - add poll task to the wait queue
544 * @filp: file pointer being polled
545 * @wait_address: wait_q to block on
546 * @p: poll state
547 *
548 * called by files poll operation to add v9fs-poll task to files wait queue
549 */
550
551 static void
p9_pollwait(struct file * filp,wait_queue_head_t * wait_address,poll_table * p)552 p9_pollwait(struct file *filp, wait_queue_head_t *wait_address, poll_table *p)
553 {
554 struct p9_conn *m = container_of(p, struct p9_conn, pt);
555 struct p9_poll_wait *pwait = NULL;
556 int i;
557
558 for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) {
559 if (m->poll_wait[i].wait_addr == NULL) {
560 pwait = &m->poll_wait[i];
561 break;
562 }
563 }
564
565 if (!pwait) {
566 p9_debug(P9_DEBUG_ERROR, "not enough wait_address slots\n");
567 return;
568 }
569
570 pwait->conn = m;
571 pwait->wait_addr = wait_address;
572 init_waitqueue_func_entry(&pwait->wait, p9_pollwake);
573 add_wait_queue(wait_address, &pwait->wait);
574 }
575
576 /**
577 * p9_conn_create - initialize the per-session mux data
578 * @client: client instance
579 *
580 * Note: Creates the polling task if this is the first session.
581 */
582
p9_conn_create(struct p9_client * client)583 static void p9_conn_create(struct p9_client *client)
584 {
585 __poll_t n;
586 struct p9_trans_fd *ts = client->trans;
587 struct p9_conn *m = &ts->conn;
588
589 p9_debug(P9_DEBUG_TRANS, "client %p msize %d\n", client, client->msize);
590
591 INIT_LIST_HEAD(&m->mux_list);
592 m->client = client;
593
594 spin_lock_init(&m->req_lock);
595 INIT_LIST_HEAD(&m->req_list);
596 INIT_LIST_HEAD(&m->unsent_req_list);
597 INIT_WORK(&m->rq, p9_read_work);
598 INIT_WORK(&m->wq, p9_write_work);
599 INIT_LIST_HEAD(&m->poll_pending_link);
600 init_poll_funcptr(&m->pt, p9_pollwait);
601
602 n = p9_fd_poll(client, &m->pt, NULL);
603 if (n & EPOLLIN) {
604 p9_debug(P9_DEBUG_TRANS, "mux %p can read\n", m);
605 set_bit(Rpending, &m->wsched);
606 }
607
608 if (n & EPOLLOUT) {
609 p9_debug(P9_DEBUG_TRANS, "mux %p can write\n", m);
610 set_bit(Wpending, &m->wsched);
611 }
612 }
613
614 /**
615 * p9_poll_mux - polls a mux and schedules read or write works if necessary
616 * @m: connection to poll
617 *
618 */
619
p9_poll_mux(struct p9_conn * m)620 static void p9_poll_mux(struct p9_conn *m)
621 {
622 __poll_t n;
623 int err = -ECONNRESET;
624
625 if (m->err < 0)
626 return;
627
628 n = p9_fd_poll(m->client, NULL, &err);
629 if (n & (EPOLLERR | EPOLLHUP | EPOLLNVAL)) {
630 p9_debug(P9_DEBUG_TRANS, "error mux %p err %d\n", m, n);
631 p9_conn_cancel(m, err);
632 }
633
634 if (n & EPOLLIN) {
635 set_bit(Rpending, &m->wsched);
636 p9_debug(P9_DEBUG_TRANS, "mux %p can read\n", m);
637 if (!test_and_set_bit(Rworksched, &m->wsched)) {
638 p9_debug(P9_DEBUG_TRANS, "sched read work %p\n", m);
639 schedule_work(&m->rq);
640 }
641 }
642
643 if (n & EPOLLOUT) {
644 set_bit(Wpending, &m->wsched);
645 p9_debug(P9_DEBUG_TRANS, "mux %p can write\n", m);
646 if ((m->wsize || !list_empty(&m->unsent_req_list)) &&
647 !test_and_set_bit(Wworksched, &m->wsched)) {
648 p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m);
649 schedule_work(&m->wq);
650 }
651 }
652 }
653
654 /**
655 * p9_fd_request - send 9P request
656 * The function can sleep until the request is scheduled for sending.
657 * The function can be interrupted. Return from the function is not
658 * a guarantee that the request is sent successfully.
659 *
660 * @client: client instance
661 * @req: request to be sent
662 *
663 */
664
p9_fd_request(struct p9_client * client,struct p9_req_t * req)665 static int p9_fd_request(struct p9_client *client, struct p9_req_t *req)
666 {
667 __poll_t n;
668 struct p9_trans_fd *ts = client->trans;
669 struct p9_conn *m = &ts->conn;
670
671 p9_debug(P9_DEBUG_TRANS, "mux %p task %p tcall %p id %d\n",
672 m, current, &req->tc, req->tc.id);
673
674 spin_lock(&m->req_lock);
675
676 if (m->err < 0) {
677 spin_unlock(&m->req_lock);
678 return m->err;
679 }
680
681 WRITE_ONCE(req->status, REQ_STATUS_UNSENT);
682 list_add_tail(&req->req_list, &m->unsent_req_list);
683 spin_unlock(&m->req_lock);
684
685 if (test_and_clear_bit(Wpending, &m->wsched))
686 n = EPOLLOUT;
687 else
688 n = p9_fd_poll(m->client, NULL, NULL);
689
690 if (n & EPOLLOUT && !test_and_set_bit(Wworksched, &m->wsched))
691 schedule_work(&m->wq);
692
693 return 0;
694 }
695
p9_fd_cancel(struct p9_client * client,struct p9_req_t * req)696 static int p9_fd_cancel(struct p9_client *client, struct p9_req_t *req)
697 {
698 struct p9_trans_fd *ts = client->trans;
699 struct p9_conn *m = &ts->conn;
700 int ret = 1;
701
702 p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req);
703
704 spin_lock(&m->req_lock);
705
706 if (req->status == REQ_STATUS_UNSENT) {
707 list_del(&req->req_list);
708 WRITE_ONCE(req->status, REQ_STATUS_FLSHD);
709 p9_req_put(client, req);
710 ret = 0;
711 }
712 spin_unlock(&m->req_lock);
713
714 return ret;
715 }
716
p9_fd_cancelled(struct p9_client * client,struct p9_req_t * req)717 static int p9_fd_cancelled(struct p9_client *client, struct p9_req_t *req)
718 {
719 struct p9_trans_fd *ts = client->trans;
720 struct p9_conn *m = &ts->conn;
721
722 p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req);
723
724 spin_lock(&m->req_lock);
725 /* Ignore cancelled request if message has been received
726 * before lock.
727 */
728 if (req->status == REQ_STATUS_RCVD) {
729 spin_unlock(&m->req_lock);
730 return 0;
731 }
732
733 /* we haven't received a response for oldreq,
734 * remove it from the list.
735 */
736 list_del(&req->req_list);
737 WRITE_ONCE(req->status, REQ_STATUS_FLSHD);
738 spin_unlock(&m->req_lock);
739
740 p9_req_put(client, req);
741
742 return 0;
743 }
744
p9_fd_show_options(struct seq_file * m,struct p9_client * clnt)745 static int p9_fd_show_options(struct seq_file *m, struct p9_client *clnt)
746 {
747 if (clnt->trans_mod == &p9_tcp_trans) {
748 if (clnt->trans_opts.tcp.port != P9_PORT)
749 seq_printf(m, ",port=%u", clnt->trans_opts.tcp.port);
750 } else if (clnt->trans_mod == &p9_fd_trans) {
751 if (clnt->trans_opts.fd.rfd != ~0)
752 seq_printf(m, ",rfd=%u", clnt->trans_opts.fd.rfd);
753 if (clnt->trans_opts.fd.wfd != ~0)
754 seq_printf(m, ",wfd=%u", clnt->trans_opts.fd.wfd);
755 }
756 return 0;
757 }
758
759 /**
760 * parse_opts - parse mount options into p9_fd_opts structure
761 * @params: options string passed from mount
762 * @opts: fd transport-specific structure to parse options into
763 *
764 * Returns 0 upon success, -ERRNO upon failure
765 */
766
parse_opts(char * params,struct p9_fd_opts * opts)767 static int parse_opts(char *params, struct p9_fd_opts *opts)
768 {
769 char *p;
770 substring_t args[MAX_OPT_ARGS];
771 int option;
772 char *options, *tmp_options;
773
774 opts->port = P9_PORT;
775 opts->rfd = ~0;
776 opts->wfd = ~0;
777 opts->privport = false;
778
779 if (!params)
780 return 0;
781
782 tmp_options = kstrdup(params, GFP_KERNEL);
783 if (!tmp_options) {
784 p9_debug(P9_DEBUG_ERROR,
785 "failed to allocate copy of option string\n");
786 return -ENOMEM;
787 }
788 options = tmp_options;
789
790 while ((p = strsep(&options, ",")) != NULL) {
791 int token;
792 int r;
793 if (!*p)
794 continue;
795 token = match_token(p, tokens, args);
796 if ((token != Opt_err) && (token != Opt_privport)) {
797 r = match_int(&args[0], &option);
798 if (r < 0) {
799 p9_debug(P9_DEBUG_ERROR,
800 "integer field, but no integer?\n");
801 continue;
802 }
803 }
804 switch (token) {
805 case Opt_port:
806 opts->port = option;
807 break;
808 case Opt_rfdno:
809 opts->rfd = option;
810 break;
811 case Opt_wfdno:
812 opts->wfd = option;
813 break;
814 case Opt_privport:
815 opts->privport = true;
816 break;
817 default:
818 continue;
819 }
820 }
821
822 kfree(tmp_options);
823 return 0;
824 }
825
p9_fd_open(struct p9_client * client,int rfd,int wfd)826 static int p9_fd_open(struct p9_client *client, int rfd, int wfd)
827 {
828 struct p9_trans_fd *ts = kzalloc(sizeof(struct p9_trans_fd),
829 GFP_KERNEL);
830 if (!ts)
831 return -ENOMEM;
832
833 ts->rd = fget(rfd);
834 if (!ts->rd)
835 goto out_free_ts;
836 if (!(ts->rd->f_mode & FMODE_READ))
837 goto out_put_rd;
838 /* Prevent workers from hanging on IO when fd is a pipe.
839 * It's technically possible for userspace or concurrent mounts to
840 * modify this flag concurrently, which will likely result in a
841 * broken filesystem. However, just having bad flags here should
842 * not crash the kernel or cause any other sort of bug, so mark this
843 * particular data race as intentional so that tooling (like KCSAN)
844 * can allow it and detect further problems.
845 */
846 data_race(ts->rd->f_flags |= O_NONBLOCK);
847 ts->wr = fget(wfd);
848 if (!ts->wr)
849 goto out_put_rd;
850 if (!(ts->wr->f_mode & FMODE_WRITE))
851 goto out_put_wr;
852 data_race(ts->wr->f_flags |= O_NONBLOCK);
853
854 client->trans = ts;
855 client->status = Connected;
856
857 return 0;
858
859 out_put_wr:
860 fput(ts->wr);
861 out_put_rd:
862 fput(ts->rd);
863 out_free_ts:
864 kfree(ts);
865 return -EIO;
866 }
867
p9_socket_open(struct p9_client * client,struct socket * csocket)868 static int p9_socket_open(struct p9_client *client, struct socket *csocket)
869 {
870 struct p9_trans_fd *p;
871 struct file *file;
872
873 p = kzalloc(sizeof(struct p9_trans_fd), GFP_KERNEL);
874 if (!p) {
875 sock_release(csocket);
876 return -ENOMEM;
877 }
878
879 csocket->sk->sk_allocation = GFP_NOIO;
880 csocket->sk->sk_use_task_frag = false;
881 file = sock_alloc_file(csocket, 0, NULL);
882 if (IS_ERR(file)) {
883 pr_err("%s (%d): failed to map fd\n",
884 __func__, task_pid_nr(current));
885 kfree(p);
886 return PTR_ERR(file);
887 }
888
889 get_file(file);
890 p->wr = p->rd = file;
891 client->trans = p;
892 client->status = Connected;
893
894 p->rd->f_flags |= O_NONBLOCK;
895
896 p9_conn_create(client);
897 return 0;
898 }
899
900 /**
901 * p9_conn_destroy - cancels all pending requests of mux
902 * @m: mux to destroy
903 *
904 */
905
p9_conn_destroy(struct p9_conn * m)906 static void p9_conn_destroy(struct p9_conn *m)
907 {
908 p9_debug(P9_DEBUG_TRANS, "mux %p prev %p next %p\n",
909 m, m->mux_list.prev, m->mux_list.next);
910
911 p9_mux_poll_stop(m);
912 cancel_work_sync(&m->rq);
913 if (m->rreq) {
914 p9_req_put(m->client, m->rreq);
915 m->rreq = NULL;
916 }
917 cancel_work_sync(&m->wq);
918 if (m->wreq) {
919 p9_req_put(m->client, m->wreq);
920 m->wreq = NULL;
921 }
922
923 p9_conn_cancel(m, -ECONNRESET);
924
925 m->client = NULL;
926 }
927
928 /**
929 * p9_fd_close - shutdown file descriptor transport
930 * @client: client instance
931 *
932 */
933
p9_fd_close(struct p9_client * client)934 static void p9_fd_close(struct p9_client *client)
935 {
936 struct p9_trans_fd *ts;
937
938 if (!client)
939 return;
940
941 ts = client->trans;
942 if (!ts)
943 return;
944
945 client->status = Disconnected;
946
947 p9_conn_destroy(&ts->conn);
948
949 if (ts->rd)
950 fput(ts->rd);
951 if (ts->wr)
952 fput(ts->wr);
953
954 kfree(ts);
955 }
956
957 /*
958 * stolen from NFS - maybe should be made a generic function?
959 */
valid_ipaddr4(const char * buf)960 static inline int valid_ipaddr4(const char *buf)
961 {
962 int rc, count, in[4];
963
964 rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]);
965 if (rc != 4)
966 return -EINVAL;
967 for (count = 0; count < 4; count++) {
968 if (in[count] > 255)
969 return -EINVAL;
970 }
971 return 0;
972 }
973
p9_bind_privport(struct socket * sock)974 static int p9_bind_privport(struct socket *sock)
975 {
976 struct sockaddr_in cl;
977 int port, err = -EINVAL;
978
979 memset(&cl, 0, sizeof(cl));
980 cl.sin_family = AF_INET;
981 cl.sin_addr.s_addr = htonl(INADDR_ANY);
982 for (port = p9_ipport_resv_max; port >= p9_ipport_resv_min; port--) {
983 cl.sin_port = htons((ushort)port);
984 err = kernel_bind(sock, (struct sockaddr *)&cl, sizeof(cl));
985 if (err != -EADDRINUSE)
986 break;
987 }
988 return err;
989 }
990
991
992 static int
p9_fd_create_tcp(struct p9_client * client,const char * addr,char * args)993 p9_fd_create_tcp(struct p9_client *client, const char *addr, char *args)
994 {
995 int err;
996 struct socket *csocket;
997 struct sockaddr_in sin_server;
998 struct p9_fd_opts opts;
999
1000 err = parse_opts(args, &opts);
1001 if (err < 0)
1002 return err;
1003
1004 if (addr == NULL || valid_ipaddr4(addr) < 0)
1005 return -EINVAL;
1006
1007 csocket = NULL;
1008
1009 client->trans_opts.tcp.port = opts.port;
1010 client->trans_opts.tcp.privport = opts.privport;
1011 sin_server.sin_family = AF_INET;
1012 sin_server.sin_addr.s_addr = in_aton(addr);
1013 sin_server.sin_port = htons(opts.port);
1014 err = __sock_create(current->nsproxy->net_ns, PF_INET,
1015 SOCK_STREAM, IPPROTO_TCP, &csocket, 1);
1016 if (err) {
1017 pr_err("%s (%d): problem creating socket\n",
1018 __func__, task_pid_nr(current));
1019 return err;
1020 }
1021
1022 if (opts.privport) {
1023 err = p9_bind_privport(csocket);
1024 if (err < 0) {
1025 pr_err("%s (%d): problem binding to privport\n",
1026 __func__, task_pid_nr(current));
1027 sock_release(csocket);
1028 return err;
1029 }
1030 }
1031
1032 err = READ_ONCE(csocket->ops)->connect(csocket,
1033 (struct sockaddr *)&sin_server,
1034 sizeof(struct sockaddr_in), 0);
1035 if (err < 0) {
1036 pr_err("%s (%d): problem connecting socket to %s\n",
1037 __func__, task_pid_nr(current), addr);
1038 sock_release(csocket);
1039 return err;
1040 }
1041
1042 return p9_socket_open(client, csocket);
1043 }
1044
1045 static int
p9_fd_create_unix(struct p9_client * client,const char * addr,char * args)1046 p9_fd_create_unix(struct p9_client *client, const char *addr, char *args)
1047 {
1048 int err;
1049 struct socket *csocket;
1050 struct sockaddr_un sun_server;
1051
1052 csocket = NULL;
1053
1054 if (!addr || !strlen(addr))
1055 return -EINVAL;
1056
1057 if (strlen(addr) >= UNIX_PATH_MAX) {
1058 pr_err("%s (%d): address too long: %s\n",
1059 __func__, task_pid_nr(current), addr);
1060 return -ENAMETOOLONG;
1061 }
1062
1063 sun_server.sun_family = PF_UNIX;
1064 strcpy(sun_server.sun_path, addr);
1065 err = __sock_create(current->nsproxy->net_ns, PF_UNIX,
1066 SOCK_STREAM, 0, &csocket, 1);
1067 if (err < 0) {
1068 pr_err("%s (%d): problem creating socket\n",
1069 __func__, task_pid_nr(current));
1070
1071 return err;
1072 }
1073 err = READ_ONCE(csocket->ops)->connect(csocket, (struct sockaddr *)&sun_server,
1074 sizeof(struct sockaddr_un) - 1, 0);
1075 if (err < 0) {
1076 pr_err("%s (%d): problem connecting socket: %s: %d\n",
1077 __func__, task_pid_nr(current), addr, err);
1078 sock_release(csocket);
1079 return err;
1080 }
1081
1082 return p9_socket_open(client, csocket);
1083 }
1084
1085 static int
p9_fd_create(struct p9_client * client,const char * addr,char * args)1086 p9_fd_create(struct p9_client *client, const char *addr, char *args)
1087 {
1088 int err;
1089 struct p9_fd_opts opts;
1090
1091 err = parse_opts(args, &opts);
1092 if (err < 0)
1093 return err;
1094 client->trans_opts.fd.rfd = opts.rfd;
1095 client->trans_opts.fd.wfd = opts.wfd;
1096
1097 if (opts.rfd == ~0 || opts.wfd == ~0) {
1098 pr_err("Insufficient options for proto=fd\n");
1099 return -ENOPROTOOPT;
1100 }
1101
1102 err = p9_fd_open(client, opts.rfd, opts.wfd);
1103 if (err < 0)
1104 return err;
1105
1106 p9_conn_create(client);
1107
1108 return 0;
1109 }
1110
1111 static struct p9_trans_module p9_tcp_trans = {
1112 .name = "tcp",
1113 .maxsize = MAX_SOCK_BUF,
1114 .pooled_rbuffers = false,
1115 .def = 0,
1116 .create = p9_fd_create_tcp,
1117 .close = p9_fd_close,
1118 .request = p9_fd_request,
1119 .cancel = p9_fd_cancel,
1120 .cancelled = p9_fd_cancelled,
1121 .show_options = p9_fd_show_options,
1122 .owner = THIS_MODULE,
1123 };
1124 MODULE_ALIAS_9P("tcp");
1125
1126 static struct p9_trans_module p9_unix_trans = {
1127 .name = "unix",
1128 .maxsize = MAX_SOCK_BUF,
1129 .def = 0,
1130 .create = p9_fd_create_unix,
1131 .close = p9_fd_close,
1132 .request = p9_fd_request,
1133 .cancel = p9_fd_cancel,
1134 .cancelled = p9_fd_cancelled,
1135 .show_options = p9_fd_show_options,
1136 .owner = THIS_MODULE,
1137 };
1138 MODULE_ALIAS_9P("unix");
1139
1140 static struct p9_trans_module p9_fd_trans = {
1141 .name = "fd",
1142 .maxsize = MAX_SOCK_BUF,
1143 .def = 0,
1144 .create = p9_fd_create,
1145 .close = p9_fd_close,
1146 .request = p9_fd_request,
1147 .cancel = p9_fd_cancel,
1148 .cancelled = p9_fd_cancelled,
1149 .show_options = p9_fd_show_options,
1150 .owner = THIS_MODULE,
1151 };
1152 MODULE_ALIAS_9P("fd");
1153
1154 /**
1155 * p9_poll_workfn - poll worker thread
1156 * @work: work queue
1157 *
1158 * polls all v9fs transports for new events and queues the appropriate
1159 * work to the work queue
1160 *
1161 */
1162
p9_poll_workfn(struct work_struct * work)1163 static void p9_poll_workfn(struct work_struct *work)
1164 {
1165 unsigned long flags;
1166
1167 p9_debug(P9_DEBUG_TRANS, "start %p\n", current);
1168
1169 spin_lock_irqsave(&p9_poll_lock, flags);
1170 while (!list_empty(&p9_poll_pending_list)) {
1171 struct p9_conn *conn = list_first_entry(&p9_poll_pending_list,
1172 struct p9_conn,
1173 poll_pending_link);
1174 list_del_init(&conn->poll_pending_link);
1175 spin_unlock_irqrestore(&p9_poll_lock, flags);
1176
1177 p9_poll_mux(conn);
1178
1179 spin_lock_irqsave(&p9_poll_lock, flags);
1180 }
1181 spin_unlock_irqrestore(&p9_poll_lock, flags);
1182
1183 p9_debug(P9_DEBUG_TRANS, "finish\n");
1184 }
1185
p9_trans_fd_init(void)1186 static int __init p9_trans_fd_init(void)
1187 {
1188 v9fs_register_trans(&p9_tcp_trans);
1189 v9fs_register_trans(&p9_unix_trans);
1190 v9fs_register_trans(&p9_fd_trans);
1191
1192 return 0;
1193 }
1194
p9_trans_fd_exit(void)1195 static void __exit p9_trans_fd_exit(void)
1196 {
1197 flush_work(&p9_poll_work);
1198 v9fs_unregister_trans(&p9_tcp_trans);
1199 v9fs_unregister_trans(&p9_unix_trans);
1200 v9fs_unregister_trans(&p9_fd_trans);
1201 }
1202
1203 module_init(p9_trans_fd_init);
1204 module_exit(p9_trans_fd_exit);
1205
1206 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
1207 MODULE_DESCRIPTION("Filedescriptor Transport for 9P");
1208 MODULE_LICENSE("GPL");
1209