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 * @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 112struct 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 142struct p9_trans_fd { 143 struct file *rd; 144 struct file *wr; 145 struct p9_conn conn; 146}; 147 148static void p9_poll_workfn(struct work_struct *work); 149 150static DEFINE_SPINLOCK(p9_poll_lock); 151static LIST_HEAD(p9_poll_pending_list); 152static DECLARE_WORK(p9_poll_work, p9_poll_workfn); 153 154static unsigned int p9_ipport_resv_min = P9_DEF_MIN_RESVPORT; 155static unsigned int p9_ipport_resv_max = P9_DEF_MAX_RESVPORT; 156 157static 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 185static 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 221static __poll_t 222p9_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 250static 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 278static 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 389end_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; 405error: 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 418static 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 444static 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 503end_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 521error: 522 p9_conn_cancel(m, err); 523 clear_bit(Wworksched, &m->wsched); 524} 525 526static 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 551static void 552p9_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 583static 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 620static 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 665static 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 696static 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 717static 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 745static 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 767static 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 826static 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 859out_put_wr: 860 fput(ts->wr); 861out_put_rd: 862 fput(ts->rd); 863out_free_ts: 864 kfree(ts); 865 return -EIO; 866} 867 868static 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 906static 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 934static 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 */ 960static 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 974static 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 992static int 993p9_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 1045static int 1046p9_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 1085static int 1086p9_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 1111static 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}; 1124MODULE_ALIAS_9P("tcp"); 1125 1126static 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}; 1138MODULE_ALIAS_9P("unix"); 1139 1140static 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}; 1152MODULE_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 1163static 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 1186static 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 1195static 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 1203module_init(p9_trans_fd_init); 1204module_exit(p9_trans_fd_exit); 1205 1206MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>"); 1207MODULE_DESCRIPTION("Filedescriptor Transport for 9P"); 1208MODULE_LICENSE("GPL"); 1209