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
37static struct p9_trans_module p9_tcp_trans;
38static 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
48struct 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
60enum {
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
67static 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
75enum {
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
82struct 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
113struct 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
143struct p9_trans_fd {
144 struct file *rd;
145 struct file *wr;
146 struct p9_conn conn;
147};
148
149static void p9_poll_workfn(struct work_struct *work);
150
151static DEFINE_SPINLOCK(p9_poll_lock);
152static LIST_HEAD(p9_poll_pending_list);
153static DECLARE_WORK(p9_poll_work, p9_poll_workfn);
154
155static unsigned int p9_ipport_resv_min = P9_DEF_MIN_RESVPORT;
156static unsigned int p9_ipport_resv_max = P9_DEF_MAX_RESVPORT;
157
158static 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(wq_head: pwait->wait_addr, wq_entry: &pwait->wait);
168 pwait->wait_addr = NULL;
169 }
170 }
171
172 spin_lock_irqsave(&p9_poll_lock, flags);
173 list_del_init(entry: &m->poll_pending_link);
174 spin_unlock_irqrestore(lock: &p9_poll_lock, flags);
175
176 flush_work(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
186static 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(lock: &m->req_lock);
194
195 if (m->err) {
196 spin_unlock(lock: &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(list: &req->req_list, head: &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(list: &req->req_list, head: &cancel_list);
208 WRITE_ONCE(req->status, REQ_STATUS_ERROR);
209 }
210
211 spin_unlock(lock: &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(entry: &req->req_list);
216 if (!req->t_err)
217 req->t_err = err;
218 p9_client_cb(c: m->client, req, status: REQ_STATUS_ERROR);
219 }
220}
221
222static __poll_t
223p9_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(file: ts->rd, pt);
238 if (ts->rd != ts->wr)
239 ret = (ret & ~EPOLLOUT) | (vfs_poll(file: 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
251static 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
279static 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(nr: Rpending, addr: &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(client: m->client, v: m->rc.sdata + m->rc.offset,
303 len: 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(pdu: &m->rc, size: &m->rc.size, NULL, NULL, rewind: 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(c: m->client, tag: 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(c: m->client, r: 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(lock: &m->req_lock);
367 if (m->rreq->status == REQ_STATUS_SENT) {
368 list_del(entry: &m->rreq->req_list);
369 p9_client_cb(c: m->client, req: m->rreq, status: 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(lock: &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(lock: &m->req_lock);
383 m->rc.sdata = NULL;
384 m->rc.offset = 0;
385 m->rc.capacity = 0;
386 p9_req_put(c: m->client, r: m->rreq);
387 m->rreq = NULL;
388 }
389
390end_clear:
391 clear_bit(nr: Rworksched, addr: &m->wsched);
392
393 if (!list_empty(head: &m->req_list)) {
394 if (test_and_clear_bit(nr: Rpending, addr: &m->wsched))
395 n = EPOLLIN;
396 else
397 n = p9_fd_poll(client: m->client, NULL, NULL);
398
399 if ((n & EPOLLIN) && !test_and_set_bit(nr: Rworksched, addr: &m->wsched)) {
400 p9_debug(P9_DEBUG_TRANS, "sched read work %p\n", m);
401 schedule_work(work: &m->rq);
402 }
403 }
404
405 return;
406error:
407 p9_conn_cancel(m, err);
408 clear_bit(nr: Rworksched, addr: &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
419static 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
445static 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(nr: Wworksched, addr: &m->wsched);
456 return;
457 }
458
459 if (!m->wsize) {
460 spin_lock(lock: &m->req_lock);
461 if (list_empty(head: &m->unsent_req_list)) {
462 clear_bit(nr: Wworksched, addr: &m->wsched);
463 spin_unlock(lock: &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(list: &req->req_list, head: &m->req_list);
472
473 m->wbuf = req->tc.sdata;
474 m->wsize = req->tc.size;
475 m->wpos = 0;
476 p9_req_get(r: req);
477 m->wreq = req;
478 spin_unlock(lock: &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(nr: Wpending, addr: &m->wsched);
484 err = p9_fd_write(client: m->client, v: m->wbuf + m->wpos, len: 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(c: m->client, r: m->wreq);
501 m->wreq = NULL;
502 }
503
504end_clear:
505 clear_bit(nr: Wworksched, addr: &m->wsched);
506
507 if (m->wsize || !list_empty(head: &m->unsent_req_list)) {
508 if (test_and_clear_bit(nr: Wpending, addr: &m->wsched))
509 n = EPOLLOUT;
510 else
511 n = p9_fd_poll(client: m->client, NULL, NULL);
512
513 if ((n & EPOLLOUT) &&
514 !test_and_set_bit(nr: Wworksched, addr: &m->wsched)) {
515 p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m);
516 schedule_work(work: &m->wq);
517 }
518 }
519
520 return;
521
522error:
523 p9_conn_cancel(m, err);
524 clear_bit(nr: Wworksched, addr: &m->wsched);
525}
526
527static 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(head: &m->poll_pending_link))
536 list_add_tail(new: &m->poll_pending_link, head: &p9_poll_pending_list);
537 spin_unlock_irqrestore(lock: &p9_poll_lock, flags);
538
539 schedule_work(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
552static void
553p9_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(wq_entry: &pwait->wait, func: p9_pollwake);
574 add_wait_queue(wq_head: wait_address, wq_entry: &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
584static 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(list: &m->mux_list);
593 m->client = client;
594
595 spin_lock_init(&m->req_lock);
596 INIT_LIST_HEAD(list: &m->req_list);
597 INIT_LIST_HEAD(list: &m->unsent_req_list);
598 INIT_WORK(&m->rq, p9_read_work);
599 INIT_WORK(&m->wq, p9_write_work);
600 INIT_LIST_HEAD(list: &m->poll_pending_link);
601 init_poll_funcptr(pt: &m->pt, qproc: p9_pollwait);
602
603 n = p9_fd_poll(client, pt: &m->pt, NULL);
604 if (n & EPOLLIN) {
605 p9_debug(P9_DEBUG_TRANS, "mux %p can read\n", m);
606 set_bit(nr: Rpending, addr: &m->wsched);
607 }
608
609 if (n & EPOLLOUT) {
610 p9_debug(P9_DEBUG_TRANS, "mux %p can write\n", m);
611 set_bit(nr: Wpending, addr: &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
621static 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(client: m->client, NULL, err: &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(nr: Rpending, addr: &m->wsched);
637 p9_debug(P9_DEBUG_TRANS, "mux %p can read\n", m);
638 if (!test_and_set_bit(nr: Rworksched, addr: &m->wsched)) {
639 p9_debug(P9_DEBUG_TRANS, "sched read work %p\n", m);
640 schedule_work(work: &m->rq);
641 }
642 }
643
644 if (n & EPOLLOUT) {
645 set_bit(nr: Wpending, addr: &m->wsched);
646 p9_debug(P9_DEBUG_TRANS, "mux %p can write\n", m);
647 if ((m->wsize || !list_empty(head: &m->unsent_req_list)) &&
648 !test_and_set_bit(nr: Wworksched, addr: &m->wsched)) {
649 p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m);
650 schedule_work(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
666static 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
675 spin_lock(lock: &m->req_lock);
676
677 if (m->err < 0) {
678 spin_unlock(lock: &m->req_lock);
679 return m->err;
680 }
681
682 WRITE_ONCE(req->status, REQ_STATUS_UNSENT);
683 list_add_tail(new: &req->req_list, head: &m->unsent_req_list);
684 spin_unlock(lock: &m->req_lock);
685
686 if (test_and_clear_bit(nr: Wpending, addr: &m->wsched))
687 n = EPOLLOUT;
688 else
689 n = p9_fd_poll(client: m->client, NULL, NULL);
690
691 if (n & EPOLLOUT && !test_and_set_bit(nr: Wworksched, addr: &m->wsched))
692 schedule_work(work: &m->wq);
693
694 return 0;
695}
696
697static int p9_fd_cancel(struct p9_client *client, struct p9_req_t *req)
698{
699 struct p9_trans_fd *ts = client->trans;
700 struct p9_conn *m = &ts->conn;
701 int ret = 1;
702
703 p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req);
704
705 spin_lock(lock: &m->req_lock);
706
707 if (req->status == REQ_STATUS_UNSENT) {
708 list_del(entry: &req->req_list);
709 WRITE_ONCE(req->status, REQ_STATUS_FLSHD);
710 p9_req_put(c: client, r: req);
711 ret = 0;
712 }
713 spin_unlock(lock: &m->req_lock);
714
715 return ret;
716}
717
718static int p9_fd_cancelled(struct p9_client *client, struct p9_req_t *req)
719{
720 struct p9_trans_fd *ts = client->trans;
721 struct p9_conn *m = &ts->conn;
722
723 p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req);
724
725 spin_lock(lock: &m->req_lock);
726 /* Ignore cancelled request if message has been received
727 * before lock.
728 */
729 if (req->status == REQ_STATUS_RCVD) {
730 spin_unlock(lock: &m->req_lock);
731 return 0;
732 }
733
734 /* we haven't received a response for oldreq,
735 * remove it from the list.
736 */
737 list_del(entry: &req->req_list);
738 WRITE_ONCE(req->status, REQ_STATUS_FLSHD);
739 spin_unlock(lock: &m->req_lock);
740
741 p9_req_put(c: client, r: req);
742
743 return 0;
744}
745
746static int p9_fd_show_options(struct seq_file *m, struct p9_client *clnt)
747{
748 if (clnt->trans_mod == &p9_tcp_trans) {
749 if (clnt->trans_opts.tcp.port != P9_PORT)
750 seq_printf(m, fmt: ",port=%u", clnt->trans_opts.tcp.port);
751 } else if (clnt->trans_mod == &p9_fd_trans) {
752 if (clnt->trans_opts.fd.rfd != ~0)
753 seq_printf(m, fmt: ",rfd=%u", clnt->trans_opts.fd.rfd);
754 if (clnt->trans_opts.fd.wfd != ~0)
755 seq_printf(m, fmt: ",wfd=%u", clnt->trans_opts.fd.wfd);
756 }
757 return 0;
758}
759
760/**
761 * parse_opts - parse mount options into p9_fd_opts structure
762 * @params: options string passed from mount
763 * @opts: fd transport-specific structure to parse options into
764 *
765 * Returns 0 upon success, -ERRNO upon failure
766 */
767
768static int parse_opts(char *params, struct p9_fd_opts *opts)
769{
770 char *p;
771 substring_t args[MAX_OPT_ARGS];
772 int option;
773 char *options, *tmp_options;
774
775 opts->port = P9_PORT;
776 opts->rfd = ~0;
777 opts->wfd = ~0;
778 opts->privport = false;
779
780 if (!params)
781 return 0;
782
783 tmp_options = kstrdup(s: params, GFP_KERNEL);
784 if (!tmp_options) {
785 p9_debug(P9_DEBUG_ERROR,
786 "failed to allocate copy of option string\n");
787 return -ENOMEM;
788 }
789 options = tmp_options;
790
791 while ((p = strsep(&options, ",")) != NULL) {
792 int token;
793 int r;
794 if (!*p)
795 continue;
796 token = match_token(p, table: tokens, args);
797 if ((token != Opt_err) && (token != Opt_privport)) {
798 r = match_int(&args[0], result: &option);
799 if (r < 0) {
800 p9_debug(P9_DEBUG_ERROR,
801 "integer field, but no integer?\n");
802 continue;
803 }
804 }
805 switch (token) {
806 case Opt_port:
807 opts->port = option;
808 break;
809 case Opt_rfdno:
810 opts->rfd = option;
811 break;
812 case Opt_wfdno:
813 opts->wfd = option;
814 break;
815 case Opt_privport:
816 opts->privport = true;
817 break;
818 default:
819 continue;
820 }
821 }
822
823 kfree(objp: tmp_options);
824 return 0;
825}
826
827static int p9_fd_open(struct p9_client *client, int rfd, int wfd)
828{
829 struct p9_trans_fd *ts = kzalloc(size: sizeof(struct p9_trans_fd),
830 GFP_KERNEL);
831 if (!ts)
832 return -ENOMEM;
833
834 ts->rd = fget(fd: rfd);
835 if (!ts->rd)
836 goto out_free_ts;
837 if (!(ts->rd->f_mode & FMODE_READ))
838 goto out_put_rd;
839 /* Prevent workers from hanging on IO when fd is a pipe.
840 * It's technically possible for userspace or concurrent mounts to
841 * modify this flag concurrently, which will likely result in a
842 * broken filesystem. However, just having bad flags here should
843 * not crash the kernel or cause any other sort of bug, so mark this
844 * particular data race as intentional so that tooling (like KCSAN)
845 * can allow it and detect further problems.
846 */
847 data_race(ts->rd->f_flags |= O_NONBLOCK);
848 ts->wr = fget(fd: wfd);
849 if (!ts->wr)
850 goto out_put_rd;
851 if (!(ts->wr->f_mode & FMODE_WRITE))
852 goto out_put_wr;
853 data_race(ts->wr->f_flags |= O_NONBLOCK);
854
855 client->trans = ts;
856 client->status = Connected;
857
858 return 0;
859
860out_put_wr:
861 fput(ts->wr);
862out_put_rd:
863 fput(ts->rd);
864out_free_ts:
865 kfree(objp: ts);
866 return -EIO;
867}
868
869static int p9_socket_open(struct p9_client *client, struct socket *csocket)
870{
871 struct p9_trans_fd *p;
872 struct file *file;
873
874 p = kzalloc(size: sizeof(struct p9_trans_fd), GFP_KERNEL);
875 if (!p) {
876 sock_release(sock: csocket);
877 return -ENOMEM;
878 }
879
880 csocket->sk->sk_allocation = GFP_NOIO;
881 csocket->sk->sk_use_task_frag = false;
882 file = sock_alloc_file(sock: csocket, flags: 0, NULL);
883 if (IS_ERR(ptr: file)) {
884 pr_err("%s (%d): failed to map fd\n",
885 __func__, task_pid_nr(current));
886 kfree(objp: p);
887 return PTR_ERR(ptr: file);
888 }
889
890 get_file(f: file);
891 p->wr = p->rd = file;
892 client->trans = p;
893 client->status = Connected;
894
895 p->rd->f_flags |= O_NONBLOCK;
896
897 p9_conn_create(client);
898 return 0;
899}
900
901/**
902 * p9_conn_destroy - cancels all pending requests of mux
903 * @m: mux to destroy
904 *
905 */
906
907static void p9_conn_destroy(struct p9_conn *m)
908{
909 p9_debug(P9_DEBUG_TRANS, "mux %p prev %p next %p\n",
910 m, m->mux_list.prev, m->mux_list.next);
911
912 p9_mux_poll_stop(m);
913 cancel_work_sync(work: &m->rq);
914 if (m->rreq) {
915 p9_req_put(c: m->client, r: m->rreq);
916 m->rreq = NULL;
917 }
918 cancel_work_sync(work: &m->wq);
919 if (m->wreq) {
920 p9_req_put(c: m->client, r: m->wreq);
921 m->wreq = NULL;
922 }
923
924 p9_conn_cancel(m, err: -ECONNRESET);
925
926 m->client = NULL;
927}
928
929/**
930 * p9_fd_close - shutdown file descriptor transport
931 * @client: client instance
932 *
933 */
934
935static void p9_fd_close(struct p9_client *client)
936{
937 struct p9_trans_fd *ts;
938
939 if (!client)
940 return;
941
942 ts = client->trans;
943 if (!ts)
944 return;
945
946 client->status = Disconnected;
947
948 p9_conn_destroy(m: &ts->conn);
949
950 if (ts->rd)
951 fput(ts->rd);
952 if (ts->wr)
953 fput(ts->wr);
954
955 kfree(objp: ts);
956}
957
958/*
959 * stolen from NFS - maybe should be made a generic function?
960 */
961static inline int valid_ipaddr4(const char *buf)
962{
963 int rc, count, in[4];
964
965 rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]);
966 if (rc != 4)
967 return -EINVAL;
968 for (count = 0; count < 4; count++) {
969 if (in[count] > 255)
970 return -EINVAL;
971 }
972 return 0;
973}
974
975static int p9_bind_privport(struct socket *sock)
976{
977 struct sockaddr_in cl;
978 int port, err = -EINVAL;
979
980 memset(&cl, 0, sizeof(cl));
981 cl.sin_family = AF_INET;
982 cl.sin_addr.s_addr = htonl(INADDR_ANY);
983 for (port = p9_ipport_resv_max; port >= p9_ipport_resv_min; port--) {
984 cl.sin_port = htons((ushort)port);
985 err = kernel_bind(sock, addr: (struct sockaddr *)&cl, addrlen: sizeof(cl));
986 if (err != -EADDRINUSE)
987 break;
988 }
989 return err;
990}
991
992
993static int
994p9_fd_create_tcp(struct p9_client *client, const char *addr, char *args)
995{
996 int err;
997 struct socket *csocket;
998 struct sockaddr_in sin_server;
999 struct p9_fd_opts opts;
1000
1001 err = parse_opts(params: args, opts: &opts);
1002 if (err < 0)
1003 return err;
1004
1005 if (addr == NULL || valid_ipaddr4(buf: addr) < 0)
1006 return -EINVAL;
1007
1008 csocket = NULL;
1009
1010 client->trans_opts.tcp.port = opts.port;
1011 client->trans_opts.tcp.privport = opts.privport;
1012 sin_server.sin_family = AF_INET;
1013 sin_server.sin_addr.s_addr = in_aton(str: addr);
1014 sin_server.sin_port = htons(opts.port);
1015 err = __sock_create(current->nsproxy->net_ns, PF_INET,
1016 type: SOCK_STREAM, IPPROTO_TCP, res: &csocket, kern: 1);
1017 if (err) {
1018 pr_err("%s (%d): problem creating socket\n",
1019 __func__, task_pid_nr(current));
1020 return err;
1021 }
1022
1023 if (opts.privport) {
1024 err = p9_bind_privport(sock: csocket);
1025 if (err < 0) {
1026 pr_err("%s (%d): problem binding to privport\n",
1027 __func__, task_pid_nr(current));
1028 sock_release(sock: csocket);
1029 return err;
1030 }
1031 }
1032
1033 err = READ_ONCE(csocket->ops)->connect(csocket,
1034 (struct sockaddr *)&sin_server,
1035 sizeof(struct sockaddr_in), 0);
1036 if (err < 0) {
1037 pr_err("%s (%d): problem connecting socket to %s\n",
1038 __func__, task_pid_nr(current), addr);
1039 sock_release(sock: csocket);
1040 return err;
1041 }
1042
1043 return p9_socket_open(client, csocket);
1044}
1045
1046static int
1047p9_fd_create_unix(struct p9_client *client, const char *addr, char *args)
1048{
1049 int err;
1050 struct socket *csocket;
1051 struct sockaddr_un sun_server;
1052
1053 csocket = NULL;
1054
1055 if (!addr || !strlen(addr))
1056 return -EINVAL;
1057
1058 if (strlen(addr) >= UNIX_PATH_MAX) {
1059 pr_err("%s (%d): address too long: %s\n",
1060 __func__, task_pid_nr(current), addr);
1061 return -ENAMETOOLONG;
1062 }
1063
1064 sun_server.sun_family = PF_UNIX;
1065 strcpy(p: sun_server.sun_path, q: addr);
1066 err = __sock_create(current->nsproxy->net_ns, PF_UNIX,
1067 type: SOCK_STREAM, proto: 0, res: &csocket, kern: 1);
1068 if (err < 0) {
1069 pr_err("%s (%d): problem creating socket\n",
1070 __func__, task_pid_nr(current));
1071
1072 return err;
1073 }
1074 err = READ_ONCE(csocket->ops)->connect(csocket, (struct sockaddr *)&sun_server,
1075 sizeof(struct sockaddr_un) - 1, 0);
1076 if (err < 0) {
1077 pr_err("%s (%d): problem connecting socket: %s: %d\n",
1078 __func__, task_pid_nr(current), addr, err);
1079 sock_release(sock: csocket);
1080 return err;
1081 }
1082
1083 return p9_socket_open(client, csocket);
1084}
1085
1086static int
1087p9_fd_create(struct p9_client *client, const char *addr, char *args)
1088{
1089 int err;
1090 struct p9_fd_opts opts;
1091
1092 err = parse_opts(params: args, opts: &opts);
1093 if (err < 0)
1094 return err;
1095 client->trans_opts.fd.rfd = opts.rfd;
1096 client->trans_opts.fd.wfd = opts.wfd;
1097
1098 if (opts.rfd == ~0 || opts.wfd == ~0) {
1099 pr_err("Insufficient options for proto=fd\n");
1100 return -ENOPROTOOPT;
1101 }
1102
1103 err = p9_fd_open(client, rfd: opts.rfd, wfd: opts.wfd);
1104 if (err < 0)
1105 return err;
1106
1107 p9_conn_create(client);
1108
1109 return 0;
1110}
1111
1112static struct p9_trans_module p9_tcp_trans = {
1113 .name = "tcp",
1114 .maxsize = MAX_SOCK_BUF,
1115 .pooled_rbuffers = false,
1116 .def = 0,
1117 .create = p9_fd_create_tcp,
1118 .close = p9_fd_close,
1119 .request = p9_fd_request,
1120 .cancel = p9_fd_cancel,
1121 .cancelled = p9_fd_cancelled,
1122 .show_options = p9_fd_show_options,
1123 .owner = THIS_MODULE,
1124};
1125MODULE_ALIAS_9P("tcp");
1126
1127static struct p9_trans_module p9_unix_trans = {
1128 .name = "unix",
1129 .maxsize = MAX_SOCK_BUF,
1130 .def = 0,
1131 .create = p9_fd_create_unix,
1132 .close = p9_fd_close,
1133 .request = p9_fd_request,
1134 .cancel = p9_fd_cancel,
1135 .cancelled = p9_fd_cancelled,
1136 .show_options = p9_fd_show_options,
1137 .owner = THIS_MODULE,
1138};
1139MODULE_ALIAS_9P("unix");
1140
1141static struct p9_trans_module p9_fd_trans = {
1142 .name = "fd",
1143 .maxsize = MAX_SOCK_BUF,
1144 .def = 0,
1145 .create = p9_fd_create,
1146 .close = p9_fd_close,
1147 .request = p9_fd_request,
1148 .cancel = p9_fd_cancel,
1149 .cancelled = p9_fd_cancelled,
1150 .show_options = p9_fd_show_options,
1151 .owner = THIS_MODULE,
1152};
1153MODULE_ALIAS_9P("fd");
1154
1155/**
1156 * p9_poll_workfn - poll worker thread
1157 * @work: work queue
1158 *
1159 * polls all v9fs transports for new events and queues the appropriate
1160 * work to the work queue
1161 *
1162 */
1163
1164static void p9_poll_workfn(struct work_struct *work)
1165{
1166 unsigned long flags;
1167
1168 p9_debug(P9_DEBUG_TRANS, "start %p\n", current);
1169
1170 spin_lock_irqsave(&p9_poll_lock, flags);
1171 while (!list_empty(head: &p9_poll_pending_list)) {
1172 struct p9_conn *conn = list_first_entry(&p9_poll_pending_list,
1173 struct p9_conn,
1174 poll_pending_link);
1175 list_del_init(entry: &conn->poll_pending_link);
1176 spin_unlock_irqrestore(lock: &p9_poll_lock, flags);
1177
1178 p9_poll_mux(m: conn);
1179
1180 spin_lock_irqsave(&p9_poll_lock, flags);
1181 }
1182 spin_unlock_irqrestore(lock: &p9_poll_lock, flags);
1183
1184 p9_debug(P9_DEBUG_TRANS, "finish\n");
1185}
1186
1187static int __init p9_trans_fd_init(void)
1188{
1189 v9fs_register_trans(m: &p9_tcp_trans);
1190 v9fs_register_trans(m: &p9_unix_trans);
1191 v9fs_register_trans(m: &p9_fd_trans);
1192
1193 return 0;
1194}
1195
1196static void __exit p9_trans_fd_exit(void)
1197{
1198 flush_work(work: &p9_poll_work);
1199 v9fs_unregister_trans(m: &p9_tcp_trans);
1200 v9fs_unregister_trans(m: &p9_unix_trans);
1201 v9fs_unregister_trans(m: &p9_fd_trans);
1202}
1203
1204module_init(p9_trans_fd_init);
1205module_exit(p9_trans_fd_exit);
1206
1207MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
1208MODULE_DESCRIPTION("Filedescriptor Transport for 9P");
1209MODULE_LICENSE("GPL");
1210

source code of linux/net/9p/trans_fd.c