trans_fd.c

   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/in6.h>
  15#include <linux/module.h>
  16#include <linux/net.h>
  17#include <linux/ipv6.h>
  18#include <linux/kthread.h>
  19#include <linux/errno.h>
  20#include <linux/kernel.h>
  21#include <linux/un.h>
  22#include <linux/uaccess.h>
  23#include <linux/inet.h>
  24#include <linux/file.h>
  25#include <linux/fs_context.h>
  26#include <linux/slab.h>
  27#include <linux/seq_file.h>
  28#include <net/9p/9p.h>
  29#include <net/9p/client.h>
  30#include <net/9p/transport.h>
  31
  32#include <linux/syscalls.h> /* killme */
  33
  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
  40enum {
  41	Rworksched = 1,		/* read work scheduled or running */
  42	Rpending = 2,		/* can read */
  43	Wworksched = 4,		/* write work scheduled or running */
  44	Wpending = 8,		/* can write */
  45};
  46
  47struct p9_poll_wait {
  48	struct p9_conn *conn;
  49	wait_queue_entry_t wait;
  50	wait_queue_head_t *wait_addr;
  51};
  52
  53/**
  54 * struct p9_conn - fd mux connection state information
  55 * @mux_list: list link for mux to manage multiple connections (?)
  56 * @client: reference to client instance for this connection
  57 * @err: error state
  58 * @req_lock: lock protecting req_list and requests statuses
  59 * @req_list: accounting for requests which have been sent
  60 * @unsent_req_list: accounting for requests that haven't been sent
  61 * @rreq: read request
  62 * @wreq: write request
  63 * @tmp_buf: temporary buffer to read in header
  64 * @rc: temporary fcall for reading current frame
  65 * @wpos: write position for current frame
  66 * @wsize: amount of data to write for current frame
  67 * @wbuf: current write buffer
  68 * @poll_pending_link: pending links to be polled per conn
  69 * @poll_wait: array of wait_q's for various worker threads
  70 * @pt: poll state
  71 * @rq: current read work
  72 * @wq: current write work
  73 * @wsched: ????
  74 *
  75 */
  76
  77struct p9_conn {
  78	struct list_head mux_list;
  79	struct p9_client *client;
  80	int err;
  81	spinlock_t req_lock;
  82	struct list_head req_list;
  83	struct list_head unsent_req_list;
  84	struct p9_req_t *rreq;
  85	struct p9_req_t *wreq;
  86	char tmp_buf[P9_HDRSZ];
  87	struct p9_fcall rc;
  88	int wpos;
  89	int wsize;
  90	char *wbuf;
  91	struct list_head poll_pending_link;
  92	struct p9_poll_wait poll_wait[MAXPOLLWADDR];
  93	poll_table pt;
  94	struct work_struct rq;
  95	struct work_struct wq;
  96	unsigned long wsched;
  97};
  98
  99/**
 100 * struct p9_trans_fd - transport state
 101 * @rd: reference to file to read from
 102 * @wr: reference of file to write to
 103 * @conn: connection state reference
 104 *
 105 */
 106
 107struct p9_trans_fd {
 108	struct file *rd;
 109	struct file *wr;
 110	struct p9_conn conn;
 111};
 112
 113static void p9_poll_workfn(struct work_struct *work);
 114
 115static DEFINE_SPINLOCK(p9_poll_lock);
 116static LIST_HEAD(p9_poll_pending_list);
 117static DECLARE_WORK(p9_poll_work, p9_poll_workfn);
 118
 119static unsigned int p9_ipport_resv_min = P9_DEF_MIN_RESVPORT;
 120static unsigned int p9_ipport_resv_max = P9_DEF_MAX_RESVPORT;
 121
 122static void p9_mux_poll_stop(struct p9_conn *m)
 123{
 124	unsigned long flags;
 125	int i;
 126
 127	for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) {
 128		struct p9_poll_wait *pwait = &m->poll_wait[i];
 129
 130		if (pwait->wait_addr) {
 131			remove_wait_queue(pwait->wait_addr, &pwait->wait);
 132			pwait->wait_addr = NULL;
 133		}
 134	}
 135
 136	spin_lock_irqsave(&p9_poll_lock, flags);
 137	list_del_init(&m->poll_pending_link);
 138	spin_unlock_irqrestore(&p9_poll_lock, flags);
 139
 140	flush_work(&p9_poll_work);
 141}
 142
 143/**
 144 * p9_conn_cancel - cancel all pending requests with error
 145 * @m: mux data
 146 * @err: error code
 147 *
 148 */
 149
 150static void p9_conn_cancel(struct p9_conn *m, int err)
 151{
 152	struct p9_req_t *req, *rtmp;
 153	LIST_HEAD(cancel_list);
 154
 155	p9_debug(P9_DEBUG_ERROR, "mux %p err %d\n", m, err);
 156
 157	spin_lock(&m->req_lock);
 158
 159	if (READ_ONCE(m->err)) {
 160		spin_unlock(&m->req_lock);
 161		return;
 162	}
 163
 164	WRITE_ONCE(m->err, err);
 165	ASSERT_EXCLUSIVE_WRITER(m->err);
 166
 167	list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) {
 168		list_move(&req->req_list, &cancel_list);
 169		WRITE_ONCE(req->status, REQ_STATUS_ERROR);
 170	}
 171	list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) {
 172		list_move(&req->req_list, &cancel_list);
 173		WRITE_ONCE(req->status, REQ_STATUS_ERROR);
 174	}
 175
 176	spin_unlock(&m->req_lock);
 177
 178	list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) {
 179		p9_debug(P9_DEBUG_ERROR, "call back req %p\n", req);
 180		list_del(&req->req_list);
 181		if (!req->t_err)
 182			req->t_err = err;
 183		p9_client_cb(m->client, req, REQ_STATUS_ERROR);
 184	}
 185}
 186
 187static __poll_t
 188p9_fd_poll(struct p9_client *client, struct poll_table_struct *pt, int *err)
 189{
 190	__poll_t ret;
 191	struct p9_trans_fd *ts = NULL;
 192
 193	if (client && client->status == Connected)
 194		ts = client->trans;
 195
 196	if (!ts) {
 197		if (err)
 198			*err = -EREMOTEIO;
 199		return EPOLLERR;
 200	}
 201
 202	ret = vfs_poll(ts->rd, pt);
 203	if (ts->rd != ts->wr)
 204		ret = (ret & ~EPOLLOUT) | (vfs_poll(ts->wr, pt) & ~EPOLLIN);
 205	return ret;
 206}
 207
 208/**
 209 * p9_fd_read- read from a fd
 210 * @client: client instance
 211 * @v: buffer to receive data into
 212 * @len: size of receive buffer
 213 *
 214 */
 215
 216static int p9_fd_read(struct p9_client *client, void *v, int len)
 217{
 218	int ret;
 219	struct p9_trans_fd *ts = NULL;
 220	loff_t pos;
 221
 222	if (client && client->status != Disconnected)
 223		ts = client->trans;
 224
 225	if (!ts)
 226		return -EREMOTEIO;
 227
 228	if (!(ts->rd->f_flags & O_NONBLOCK))
 229		p9_debug(P9_DEBUG_ERROR, "blocking read ...\n");
 230
 231	pos = ts->rd->f_pos;
 232	ret = kernel_read(ts->rd, v, len, &pos);
 233	if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
 234		client->status = Disconnected;
 235	return ret;
 236}
 237
 238/**
 239 * p9_read_work - called when there is some data to be read from a transport
 240 * @work: container of work to be done
 241 *
 242 */
 243
 244static void p9_read_work(struct work_struct *work)
 245{
 246	__poll_t n;
 247	int err;
 248	struct p9_conn *m;
 249
 250	m = container_of(work, struct p9_conn, rq);
 251
 252	if (READ_ONCE(m->err) < 0)
 253		return;
 254
 255	p9_debug(P9_DEBUG_TRANS, "start mux %p pos %zd\n", m, m->rc.offset);
 256
 257	if (!m->rc.sdata) {
 258		m->rc.sdata = m->tmp_buf;
 259		m->rc.offset = 0;
 260		m->rc.capacity = P9_HDRSZ; /* start by reading header */
 261	}
 262
 263	clear_bit(Rpending, &m->wsched);
 264	p9_debug(P9_DEBUG_TRANS, "read mux %p pos %zd size: %zd = %zd\n",
 265		 m, m->rc.offset, m->rc.capacity,
 266		 m->rc.capacity - m->rc.offset);
 267	err = p9_fd_read(m->client, m->rc.sdata + m->rc.offset,
 268			 m->rc.capacity - m->rc.offset);
 269	p9_debug(P9_DEBUG_TRANS, "mux %p got %d bytes\n", m, err);
 270	if (err == -EAGAIN)
 271		goto end_clear;
 272
 273	if (err <= 0)
 274		goto error;
 275
 276	m->rc.offset += err;
 277
 278	/* header read in */
 279	if ((!m->rreq) && (m->rc.offset == m->rc.capacity)) {
 280		p9_debug(P9_DEBUG_TRANS, "got new header\n");
 281
 282		/* Header size */
 283		m->rc.size = P9_HDRSZ;
 284		err = p9_parse_header(&m->rc, &m->rc.size, NULL, NULL, 0);
 285		if (err) {
 286			p9_debug(P9_DEBUG_ERROR,
 287				 "error parsing header: %d\n", err);
 288			goto error;
 289		}
 290
 291		p9_debug(P9_DEBUG_TRANS,
 292			 "mux %p pkt: size: %d bytes tag: %d\n",
 293			 m, m->rc.size, m->rc.tag);
 294
 295		m->rreq = p9_tag_lookup(m->client, m->rc.tag);
 296		if (!m->rreq || (m->rreq->status != REQ_STATUS_SENT)) {
 297			p9_debug(P9_DEBUG_ERROR, "Unexpected packet tag %d\n",
 298				 m->rc.tag);
 299			err = -EIO;
 300			goto error;
 301		}
 302
 303		if (m->rc.size > m->rreq->rc.capacity) {
 304			p9_debug(P9_DEBUG_ERROR,
 305				 "requested packet size too big: %d for tag %d with capacity %zd\n",
 306				 m->rc.size, m->rc.tag, m->rreq->rc.capacity);
 307			err = -EIO;
 308			goto error;
 309		}
 310
 311		if (!m->rreq->rc.sdata) {
 312			p9_debug(P9_DEBUG_ERROR,
 313				 "No recv fcall for tag %d (req %p), disconnecting!\n",
 314				 m->rc.tag, m->rreq);
 315			p9_req_put(m->client, m->rreq);
 316			m->rreq = NULL;
 317			err = -EIO;
 318			goto error;
 319		}
 320		m->rc.sdata = m->rreq->rc.sdata;
 321		memcpy(m->rc.sdata, m->tmp_buf, m->rc.capacity);
 322		m->rc.capacity = m->rc.size;
 323	}
 324
 325	/* packet is read in
 326	 * not an else because some packets (like clunk) have no payload
 327	 */
 328	if ((m->rreq) && (m->rc.offset == m->rc.capacity)) {
 329		p9_debug(P9_DEBUG_TRANS, "got new packet\n");
 330		m->rreq->rc.size = m->rc.offset;
 331		spin_lock(&m->req_lock);
 332		if (m->rreq->status == REQ_STATUS_SENT) {
 333			list_del(&m->rreq->req_list);
 334			p9_client_cb(m->client, m->rreq, REQ_STATUS_RCVD);
 335		} else if (m->rreq->status == REQ_STATUS_FLSHD) {
 336			/* Ignore replies associated with a cancelled request. */
 337			p9_debug(P9_DEBUG_TRANS,
 338				 "Ignore replies associated with a cancelled request\n");
 339		} else {
 340			spin_unlock(&m->req_lock);
 341			p9_debug(P9_DEBUG_ERROR,
 342				 "Request tag %d errored out while we were reading the reply\n",
 343				 m->rc.tag);
 344			err = -EIO;
 345			goto error;
 346		}
 347		spin_unlock(&m->req_lock);
 348		m->rc.sdata = NULL;
 349		m->rc.offset = 0;
 350		m->rc.capacity = 0;
 351		p9_req_put(m->client, m->rreq);
 352		m->rreq = NULL;
 353	}
 354
 355end_clear:
 356	clear_bit(Rworksched, &m->wsched);
 357
 358	if (!list_empty(&m->req_list)) {
 359		if (test_and_clear_bit(Rpending, &m->wsched))
 360			n = EPOLLIN;
 361		else
 362			n = p9_fd_poll(m->client, NULL, NULL);
 363
 364		if ((n & EPOLLIN) && !test_and_set_bit(Rworksched, &m->wsched)) {
 365			p9_debug(P9_DEBUG_TRANS, "sched read work %p\n", m);
 366			schedule_work(&m->rq);
 367		}
 368	}
 369
 370	return;
 371error:
 372	p9_conn_cancel(m, err);
 373	clear_bit(Rworksched, &m->wsched);
 374}
 375
 376/**
 377 * p9_fd_write - write to a socket
 378 * @client: client instance
 379 * @v: buffer to send data from
 380 * @len: size of send buffer
 381 *
 382 */
 383
 384static int p9_fd_write(struct p9_client *client, void *v, int len)
 385{
 386	ssize_t ret;
 387	struct p9_trans_fd *ts = NULL;
 388
 389	if (client && client->status != Disconnected)
 390		ts = client->trans;
 391
 392	if (!ts)
 393		return -EREMOTEIO;
 394
 395	if (!(ts->wr->f_flags & O_NONBLOCK))
 396		p9_debug(P9_DEBUG_ERROR, "blocking write ...\n");
 397
 398	ret = kernel_write(ts->wr, v, len, &ts->wr->f_pos);
 399	if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
 400		client->status = Disconnected;
 401	return ret;
 402}
 403
 404/**
 405 * p9_write_work - called when a transport can send some data
 406 * @work: container for work to be done
 407 *
 408 */
 409
 410static void p9_write_work(struct work_struct *work)
 411{
 412	__poll_t n;
 413	int err;
 414	struct p9_conn *m;
 415	struct p9_req_t *req;
 416
 417	m = container_of(work, struct p9_conn, wq);
 418
 419	if (READ_ONCE(m->err) < 0) {
 420		clear_bit(Wworksched, &m->wsched);
 421		return;
 422	}
 423
 424	if (!m->wsize) {
 425		spin_lock(&m->req_lock);
 426		if (list_empty(&m->unsent_req_list)) {
 427			clear_bit(Wworksched, &m->wsched);
 428			spin_unlock(&m->req_lock);
 429			return;
 430		}
 431
 432		req = list_entry(m->unsent_req_list.next, struct p9_req_t,
 433			       req_list);
 434		WRITE_ONCE(req->status, REQ_STATUS_SENT);
 435		p9_debug(P9_DEBUG_TRANS, "move req %p\n", req);
 436		list_move_tail(&req->req_list, &m->req_list);
 437
 438		m->wbuf = req->tc.sdata;
 439		m->wsize = req->tc.size;
 440		m->wpos = 0;
 441		p9_req_get(req);
 442		m->wreq = req;
 443		spin_unlock(&m->req_lock);
 444	}
 445
 446	p9_debug(P9_DEBUG_TRANS, "mux %p pos %d size %d\n",
 447		 m, m->wpos, m->wsize);
 448	clear_bit(Wpending, &m->wsched);
 449	err = p9_fd_write(m->client, m->wbuf + m->wpos, m->wsize - m->wpos);
 450	p9_debug(P9_DEBUG_TRANS, "mux %p sent %d bytes\n", m, err);
 451	if (err == -EAGAIN)
 452		goto end_clear;
 453
 454
 455	if (err < 0)
 456		goto error;
 457	else if (err == 0) {
 458		err = -EREMOTEIO;
 459		goto error;
 460	}
 461
 462	m->wpos += err;
 463	if (m->wpos == m->wsize) {
 464		m->wpos = m->wsize = 0;
 465		p9_req_put(m->client, m->wreq);
 466		m->wreq = NULL;
 467	}
 468
 469end_clear:
 470	clear_bit(Wworksched, &m->wsched);
 471
 472	if (m->wsize || !list_empty(&m->unsent_req_list)) {
 473		if (test_and_clear_bit(Wpending, &m->wsched))
 474			n = EPOLLOUT;
 475		else
 476			n = p9_fd_poll(m->client, NULL, NULL);
 477
 478		if ((n & EPOLLOUT) &&
 479		   !test_and_set_bit(Wworksched, &m->wsched)) {
 480			p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m);
 481			schedule_work(&m->wq);
 482		}
 483	}
 484
 485	return;
 486
 487error:
 488	p9_conn_cancel(m, err);
 489	clear_bit(Wworksched, &m->wsched);
 490}
 491
 492static int p9_pollwake(wait_queue_entry_t *wait, unsigned int mode, int sync, void *key)
 493{
 494	struct p9_poll_wait *pwait =
 495		container_of(wait, struct p9_poll_wait, wait);
 496	struct p9_conn *m = pwait->conn;
 497	unsigned long flags;
 498
 499	spin_lock_irqsave(&p9_poll_lock, flags);
 500	if (list_empty(&m->poll_pending_link))
 501		list_add_tail(&m->poll_pending_link, &p9_poll_pending_list);
 502	spin_unlock_irqrestore(&p9_poll_lock, flags);
 503
 504	schedule_work(&p9_poll_work);
 505	return 1;
 506}
 507
 508/**
 509 * p9_pollwait - add poll task to the wait queue
 510 * @filp: file pointer being polled
 511 * @wait_address: wait_q to block on
 512 * @p: poll state
 513 *
 514 * called by files poll operation to add v9fs-poll task to files wait queue
 515 */
 516
 517static void
 518p9_pollwait(struct file *filp, wait_queue_head_t *wait_address, poll_table *p)
 519{
 520	struct p9_conn *m = container_of(p, struct p9_conn, pt);
 521	struct p9_poll_wait *pwait = NULL;
 522	int i;
 523
 524	for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) {
 525		if (m->poll_wait[i].wait_addr == NULL) {
 526			pwait = &m->poll_wait[i];
 527			break;
 528		}
 529	}
 530
 531	if (!pwait) {
 532		p9_debug(P9_DEBUG_ERROR, "not enough wait_address slots\n");
 533		return;
 534	}
 535
 536	pwait->conn = m;
 537	pwait->wait_addr = wait_address;
 538	init_waitqueue_func_entry(&pwait->wait, p9_pollwake);
 539	add_wait_queue(wait_address, &pwait->wait);
 540}
 541
 542/**
 543 * p9_conn_create - initialize the per-session mux data
 544 * @client: client instance
 545 *
 546 * Note: Creates the polling task if this is the first session.
 547 */
 548
 549static void p9_conn_create(struct p9_client *client)
 550{
 551	__poll_t n;
 552	struct p9_trans_fd *ts = client->trans;
 553	struct p9_conn *m = &ts->conn;
 554
 555	p9_debug(P9_DEBUG_TRANS, "client %p msize %d\n", client, client->msize);
 556
 557	INIT_LIST_HEAD(&m->mux_list);
 558	m->client = client;
 559
 560	spin_lock_init(&m->req_lock);
 561	INIT_LIST_HEAD(&m->req_list);
 562	INIT_LIST_HEAD(&m->unsent_req_list);
 563	INIT_WORK(&m->rq, p9_read_work);
 564	INIT_WORK(&m->wq, p9_write_work);
 565	INIT_LIST_HEAD(&m->poll_pending_link);
 566	init_poll_funcptr(&m->pt, p9_pollwait);
 567
 568	n = p9_fd_poll(client, &m->pt, NULL);
 569	if (n & EPOLLIN) {
 570		p9_debug(P9_DEBUG_TRANS, "mux %p can read\n", m);
 571		set_bit(Rpending, &m->wsched);
 572	}
 573
 574	if (n & EPOLLOUT) {
 575		p9_debug(P9_DEBUG_TRANS, "mux %p can write\n", m);
 576		set_bit(Wpending, &m->wsched);
 577	}
 578}
 579
 580/**
 581 * p9_poll_mux - polls a mux and schedules read or write works if necessary
 582 * @m: connection to poll
 583 *
 584 */
 585
 586static void p9_poll_mux(struct p9_conn *m)
 587{
 588	__poll_t n;
 589	int err = -ECONNRESET;
 590
 591	if (READ_ONCE(m->err) < 0)
 592		return;
 593
 594	n = p9_fd_poll(m->client, NULL, &err);
 595	if (n & (EPOLLERR | EPOLLHUP | EPOLLNVAL)) {
 596		p9_debug(P9_DEBUG_TRANS, "error mux %p err %d\n", m, n);
 597		p9_conn_cancel(m, err);
 598	}
 599
 600	if (n & EPOLLIN) {
 601		set_bit(Rpending, &m->wsched);
 602		p9_debug(P9_DEBUG_TRANS, "mux %p can read\n", m);
 603		if (!test_and_set_bit(Rworksched, &m->wsched)) {
 604			p9_debug(P9_DEBUG_TRANS, "sched read work %p\n", m);
 605			schedule_work(&m->rq);
 606		}
 607	}
 608
 609	if (n & EPOLLOUT) {
 610		set_bit(Wpending, &m->wsched);
 611		p9_debug(P9_DEBUG_TRANS, "mux %p can write\n", m);
 612		if ((m->wsize || !list_empty(&m->unsent_req_list)) &&
 613		    !test_and_set_bit(Wworksched, &m->wsched)) {
 614			p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m);
 615			schedule_work(&m->wq);
 616		}
 617	}
 618}
 619
 620/**
 621 * p9_fd_request - send 9P request
 622 * The function can sleep until the request is scheduled for sending.
 623 * The function can be interrupted. Return from the function is not
 624 * a guarantee that the request is sent successfully.
 625 *
 626 * @client: client instance
 627 * @req: request to be sent
 628 *
 629 */
 630
 631static int p9_fd_request(struct p9_client *client, struct p9_req_t *req)
 632{
 633	int err;
 634	struct p9_trans_fd *ts = client->trans;
 635	struct p9_conn *m = &ts->conn;
 636
 637	p9_debug(P9_DEBUG_TRANS, "mux %p task %p tcall %p id %d\n",
 638		 m, current, &req->tc, req->tc.id);
 639
 640	spin_lock(&m->req_lock);
 641
 642	err = READ_ONCE(m->err);
 643	if (err < 0) {
 644		spin_unlock(&m->req_lock);
 645		return err;
 646	}
 647
 648	WRITE_ONCE(req->status, REQ_STATUS_UNSENT);
 649	list_add_tail(&req->req_list, &m->unsent_req_list);
 650	spin_unlock(&m->req_lock);
 651
 652	p9_poll_mux(m);
 653
 654	return 0;
 655}
 656
 657static int p9_fd_cancel(struct p9_client *client, struct p9_req_t *req)
 658{
 659	struct p9_trans_fd *ts = client->trans;
 660	struct p9_conn *m = &ts->conn;
 661	int ret = 1;
 662
 663	p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req);
 664
 665	spin_lock(&m->req_lock);
 666
 667	if (req->status == REQ_STATUS_UNSENT) {
 668		list_del(&req->req_list);
 669		WRITE_ONCE(req->status, REQ_STATUS_FLSHD);
 670		p9_req_put(client, req);
 671		ret = 0;
 672	}
 673	spin_unlock(&m->req_lock);
 674
 675	return ret;
 676}
 677
 678static int p9_fd_cancelled(struct p9_client *client, struct p9_req_t *req)
 679{
 680	struct p9_trans_fd *ts = client->trans;
 681	struct p9_conn *m = &ts->conn;
 682
 683	p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req);
 684
 685	spin_lock(&m->req_lock);
 686	/* Ignore cancelled request if status changed since the request was
 687	 * processed in p9_client_flush()
 688	*/
 689	if (req->status != REQ_STATUS_SENT) {
 690		spin_unlock(&m->req_lock);
 691		return 0;
 692	}
 693
 694	/* we haven't received a response for oldreq,
 695	 * remove it from the list.
 696	 */
 697	list_del(&req->req_list);
 698	WRITE_ONCE(req->status, REQ_STATUS_FLSHD);
 699	spin_unlock(&m->req_lock);
 700
 701	p9_req_put(client, req);
 702
 703	return 0;
 704}
 705
 706static int p9_fd_show_options(struct seq_file *m, struct p9_client *clnt)
 707{
 708	if (clnt->trans_mod == &p9_tcp_trans) {
 709		if (clnt->trans_opts.tcp.port != P9_FD_PORT)
 710			seq_printf(m, ",port=%u", clnt->trans_opts.tcp.port);
 711	} else if (clnt->trans_mod == &p9_fd_trans) {
 712		if (clnt->trans_opts.fd.rfd != ~0)
 713			seq_printf(m, ",rfd=%u", clnt->trans_opts.fd.rfd);
 714		if (clnt->trans_opts.fd.wfd != ~0)
 715			seq_printf(m, ",wfd=%u", clnt->trans_opts.fd.wfd);
 716	}
 717	return 0;
 718}
 719
 720static int p9_fd_open(struct p9_client *client, int rfd, int wfd)
 721{
 722	struct p9_trans_fd *ts = kzalloc(sizeof(struct p9_trans_fd),
 723					   GFP_KERNEL);
 724	if (!ts)
 725		return -ENOMEM;
 726
 727	ts->rd = fget(rfd);
 728	if (!ts->rd)
 729		goto out_free_ts;
 730	if (!(ts->rd->f_mode & FMODE_READ))
 731		goto out_put_rd;
 732	/* Prevent workers from hanging on IO when fd is a pipe.
 733	 * It's technically possible for userspace or concurrent mounts to
 734	 * modify this flag concurrently, which will likely result in a
 735	 * broken filesystem. However, just having bad flags here should
 736	 * not crash the kernel or cause any other sort of bug, so mark this
 737	 * particular data race as intentional so that tooling (like KCSAN)
 738	 * can allow it and detect further problems.
 739	 */
 740	data_race(ts->rd->f_flags |= O_NONBLOCK);
 741	ts->wr = fget(wfd);
 742	if (!ts->wr)
 743		goto out_put_rd;
 744	if (!(ts->wr->f_mode & FMODE_WRITE))
 745		goto out_put_wr;
 746	data_race(ts->wr->f_flags |= O_NONBLOCK);
 747
 748	client->trans = ts;
 749	client->status = Connected;
 750
 751	return 0;
 752
 753out_put_wr:
 754	fput(ts->wr);
 755out_put_rd:
 756	fput(ts->rd);
 757out_free_ts:
 758	kfree(ts);
 759	return -EIO;
 760}
 761
 762static int p9_socket_open(struct p9_client *client, struct socket *csocket)
 763{
 764	struct p9_trans_fd *p;
 765	struct file *file;
 766
 767	p = kzalloc(sizeof(struct p9_trans_fd), GFP_KERNEL);
 768	if (!p) {
 769		sock_release(csocket);
 770		return -ENOMEM;
 771	}
 772
 773	csocket->sk->sk_allocation = GFP_NOIO;
 774	csocket->sk->sk_use_task_frag = false;
 775	file = sock_alloc_file(csocket, 0, NULL);
 776	if (IS_ERR(file)) {
 777		pr_err("%s (%d): failed to map fd\n",
 778		       __func__, task_pid_nr(current));
 779		kfree(p);
 780		return PTR_ERR(file);
 781	}
 782
 783	get_file(file);
 784	p->wr = p->rd = file;
 785	client->trans = p;
 786	client->status = Connected;
 787
 788	p->rd->f_flags |= O_NONBLOCK;
 789
 790	p9_conn_create(client);
 791	return 0;
 792}
 793
 794/**
 795 * p9_conn_destroy - cancels all pending requests of mux
 796 * @m: mux to destroy
 797 *
 798 */
 799
 800static void p9_conn_destroy(struct p9_conn *m)
 801{
 802	p9_debug(P9_DEBUG_TRANS, "mux %p prev %p next %p\n",
 803		 m, m->mux_list.prev, m->mux_list.next);
 804
 805	p9_mux_poll_stop(m);
 806	cancel_work_sync(&m->rq);
 807	if (m->rreq) {
 808		p9_req_put(m->client, m->rreq);
 809		m->rreq = NULL;
 810	}
 811	cancel_work_sync(&m->wq);
 812	if (m->wreq) {
 813		p9_req_put(m->client, m->wreq);
 814		m->wreq = NULL;
 815	}
 816
 817	p9_conn_cancel(m, -ECONNRESET);
 818
 819	m->client = NULL;
 820}
 821
 822/**
 823 * p9_fd_close - shutdown file descriptor transport
 824 * @client: client instance
 825 *
 826 */
 827
 828static void p9_fd_close(struct p9_client *client)
 829{
 830	struct p9_trans_fd *ts;
 831
 832	if (!client)
 833		return;
 834
 835	ts = client->trans;
 836	if (!ts)
 837		return;
 838
 839	client->status = Disconnected;
 840
 841	p9_conn_destroy(&ts->conn);
 842
 843	if (ts->rd)
 844		fput(ts->rd);
 845	if (ts->wr)
 846		fput(ts->wr);
 847
 848	kfree(ts);
 849}
 850
 851static int p9_bind_privport(struct socket *sock)
 852{
 853	struct sockaddr_storage stor = { 0 };
 854	int port, err = -EINVAL;
 855
 856	stor.ss_family = sock->ops->family;
 857	if (stor.ss_family == AF_INET)
 858		((struct sockaddr_in *)&stor)->sin_addr.s_addr = htonl(INADDR_ANY);
 859	else
 860		((struct sockaddr_in6 *)&stor)->sin6_addr = in6addr_any;
 861	for (port = p9_ipport_resv_max; port >= p9_ipport_resv_min; port--) {
 862		if (stor.ss_family == AF_INET)
 863			((struct sockaddr_in *)&stor)->sin_port = htons((ushort)port);
 864		else
 865			((struct sockaddr_in6 *)&stor)->sin6_port = htons((ushort)port);
 866		err = kernel_bind(sock, (struct sockaddr_unsized *)&stor, sizeof(stor));
 867		if (err != -EADDRINUSE)
 868			break;
 869	}
 870	return err;
 871}
 872
 873static int
 874p9_fd_create_tcp(struct p9_client *client, struct fs_context *fc)
 875{
 876	const char *addr = fc->source;
 877	struct v9fs_context *ctx = fc->fs_private;
 878	int err;
 879	char port_str[6];
 880	struct socket *csocket;
 881	struct sockaddr_storage stor = { 0 };
 882	struct p9_fd_opts opts;
 883
 884	/* opts are already parsed in context */
 885	opts = ctx->fd_opts;
 886
 887	if (!addr)
 888		return -EINVAL;
 889
 890	sprintf(port_str, "%u", opts.port);
 891	err = inet_pton_with_scope(current->nsproxy->net_ns, AF_UNSPEC, addr,
 892				   port_str, &stor);
 893	if (err < 0)
 894		return err;
 895
 896	csocket = NULL;
 897
 898	client->trans_opts.tcp.port = opts.port;
 899	client->trans_opts.tcp.privport = opts.privport;
 900	err = __sock_create(current->nsproxy->net_ns, stor.ss_family,
 901			    SOCK_STREAM, IPPROTO_TCP, &csocket, 1);
 902	if (err) {
 903		pr_err("%s (%d): problem creating socket\n",
 904		       __func__, task_pid_nr(current));
 905		return err;
 906	}
 907
 908	if (opts.privport) {
 909		err = p9_bind_privport(csocket);
 910		if (err < 0) {
 911			pr_err("%s (%d): problem binding to privport\n",
 912			       __func__, task_pid_nr(current));
 913			sock_release(csocket);
 914			return err;
 915		}
 916	}
 917
 918	err = READ_ONCE(csocket->ops)->connect(csocket,
 919					       (struct sockaddr_unsized *)&stor,
 920					       sizeof(stor), 0);
 921	if (err < 0) {
 922		pr_err("%s (%d): problem connecting socket to %s\n",
 923		       __func__, task_pid_nr(current), addr);
 924		sock_release(csocket);
 925		return err;
 926	}
 927
 928	return p9_socket_open(client, csocket);
 929}
 930
 931static int
 932p9_fd_create_unix(struct p9_client *client, struct fs_context *fc)
 933{
 934	const char *addr = fc->source;
 935	int err;
 936	struct socket *csocket;
 937	struct sockaddr_un sun_server;
 938
 939	csocket = NULL;
 940
 941	if (!addr || !strlen(addr))
 942		return -EINVAL;
 943
 944	if (strlen(addr) >= UNIX_PATH_MAX) {
 945		pr_err("%s (%d): address too long: %s\n",
 946		       __func__, task_pid_nr(current), addr);
 947		return -ENAMETOOLONG;
 948	}
 949
 950	sun_server.sun_family = PF_UNIX;
 951	strcpy(sun_server.sun_path, addr);
 952	err = __sock_create(current->nsproxy->net_ns, PF_UNIX,
 953			    SOCK_STREAM, 0, &csocket, 1);
 954	if (err < 0) {
 955		pr_err("%s (%d): problem creating socket\n",
 956		       __func__, task_pid_nr(current));
 957
 958		return err;
 959	}
 960	err = READ_ONCE(csocket->ops)->connect(csocket, (struct sockaddr_unsized *)&sun_server,
 961					       sizeof(struct sockaddr_un) - 1, 0);
 962	if (err < 0) {
 963		pr_err("%s (%d): problem connecting socket: %s: %d\n",
 964		       __func__, task_pid_nr(current), addr, err);
 965		sock_release(csocket);
 966		return err;
 967	}
 968
 969	return p9_socket_open(client, csocket);
 970}
 971
 972static int
 973p9_fd_create(struct p9_client *client, struct fs_context *fc)
 974{
 975	struct v9fs_context *ctx = fc->fs_private;
 976	struct p9_fd_opts opts = ctx->fd_opts;
 977	int err;
 978
 979	client->trans_opts.fd.rfd = opts.rfd;
 980	client->trans_opts.fd.wfd = opts.wfd;
 981
 982	if (opts.rfd == ~0 || opts.wfd == ~0) {
 983		pr_err("Insufficient options for proto=fd\n");
 984		return -ENOPROTOOPT;
 985	}
 986
 987	err = p9_fd_open(client, opts.rfd, opts.wfd);
 988	if (err < 0)
 989		return err;
 990
 991	p9_conn_create(client);
 992
 993	return 0;
 994}
 995
 996static struct p9_trans_module p9_tcp_trans = {
 997	.name = "tcp",
 998	.maxsize = MAX_SOCK_BUF,
 999	.pooled_rbuffers = false,
1000	.def = false,
1001	.supports_vmalloc = true,
1002	.create = p9_fd_create_tcp,
1003	.close = p9_fd_close,
1004	.request = p9_fd_request,
1005	.cancel = p9_fd_cancel,
1006	.cancelled = p9_fd_cancelled,
1007	.show_options = p9_fd_show_options,
1008	.owner = THIS_MODULE,
1009};
1010MODULE_ALIAS_9P("tcp");
1011
1012static struct p9_trans_module p9_unix_trans = {
1013	.name = "unix",
1014	.maxsize = MAX_SOCK_BUF,
1015	.def = false,
1016	.supports_vmalloc = true,
1017	.create = p9_fd_create_unix,
1018	.close = p9_fd_close,
1019	.request = p9_fd_request,
1020	.cancel = p9_fd_cancel,
1021	.cancelled = p9_fd_cancelled,
1022	.show_options = p9_fd_show_options,
1023	.owner = THIS_MODULE,
1024};
1025MODULE_ALIAS_9P("unix");
1026
1027static struct p9_trans_module p9_fd_trans = {
1028	.name = "fd",
1029	.maxsize = MAX_SOCK_BUF,
1030	.def = false,
1031	.supports_vmalloc = true,
1032	.create = p9_fd_create,
1033	.close = p9_fd_close,
1034	.request = p9_fd_request,
1035	.cancel = p9_fd_cancel,
1036	.cancelled = p9_fd_cancelled,
1037	.show_options = p9_fd_show_options,
1038	.owner = THIS_MODULE,
1039};
1040MODULE_ALIAS_9P("fd");
1041
1042/**
1043 * p9_poll_workfn - poll worker thread
1044 * @work: work queue
1045 *
1046 * polls all v9fs transports for new events and queues the appropriate
1047 * work to the work queue
1048 *
1049 */
1050
1051static void p9_poll_workfn(struct work_struct *work)
1052{
1053	unsigned long flags;
1054
1055	p9_debug(P9_DEBUG_TRANS, "start %p\n", current);
1056
1057	spin_lock_irqsave(&p9_poll_lock, flags);
1058	while (!list_empty(&p9_poll_pending_list)) {
1059		struct p9_conn *conn = list_first_entry(&p9_poll_pending_list,
1060							struct p9_conn,
1061							poll_pending_link);
1062		list_del_init(&conn->poll_pending_link);
1063		spin_unlock_irqrestore(&p9_poll_lock, flags);
1064
1065		p9_poll_mux(conn);
1066
1067		spin_lock_irqsave(&p9_poll_lock, flags);
1068	}
1069	spin_unlock_irqrestore(&p9_poll_lock, flags);
1070
1071	p9_debug(P9_DEBUG_TRANS, "finish\n");
1072}
1073
1074static int __init p9_trans_fd_init(void)
1075{
1076	v9fs_register_trans(&p9_tcp_trans);
1077	v9fs_register_trans(&p9_unix_trans);
1078	v9fs_register_trans(&p9_fd_trans);
1079
1080	return 0;
1081}
1082
1083static void __exit p9_trans_fd_exit(void)
1084{
1085	flush_work(&p9_poll_work);
1086	v9fs_unregister_trans(&p9_tcp_trans);
1087	v9fs_unregister_trans(&p9_unix_trans);
1088	v9fs_unregister_trans(&p9_fd_trans);
1089}
1090
1091module_init(p9_trans_fd_init);
1092module_exit(p9_trans_fd_exit);
1093
1094MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
1095MODULE_DESCRIPTION("Filedescriptor Transport for 9P");
1096MODULE_LICENSE("GPL");