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/parser.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 P9_PORT 564 35 #define MAX_SOCK_BUF (1024*1024) 36 #define MAXPOLLWADDR 2 37 38 static struct p9_trans_module p9_tcp_trans; 39 static struct p9_trans_module p9_fd_trans; 40 41 /** 42 * struct p9_fd_opts - per-transport options 43 * @rfd: file descriptor for reading (trans=fd) 44 * @wfd: file descriptor for writing (trans=fd) 45 * @port: port to connect to (trans=tcp) 46 * @privport: port is privileged 47 */ 48 49 struct p9_fd_opts { 50 int rfd; 51 int wfd; 52 u16 port; 53 bool privport; 54 }; 55 56 /* 57 * Option Parsing (code inspired by NFS code) 58 * - a little lazy - parse all fd-transport options 59 */ 60 61 enum { 62 /* Options that take integer arguments */ 63 Opt_port, Opt_rfdno, Opt_wfdno, Opt_err, 64 /* Options that take no arguments */ 65 Opt_privport, 66 }; 67 68 static const match_table_t tokens = { 69 {Opt_port, "port=%u"}, 70 {Opt_rfdno, "rfdno=%u"}, 71 {Opt_wfdno, "wfdno=%u"}, 72 {Opt_privport, "privport"}, 73 {Opt_err, NULL}, 74 }; 75 76 enum { 77 Rworksched = 1, /* read work scheduled or running */ 78 Rpending = 2, /* can read */ 79 Wworksched = 4, /* write work scheduled or running */ 80 Wpending = 8, /* can write */ 81 }; 82 83 struct p9_poll_wait { 84 struct p9_conn *conn; 85 wait_queue_entry_t wait; 86 wait_queue_head_t *wait_addr; 87 }; 88 89 /** 90 * struct p9_conn - fd mux connection state information 91 * @mux_list: list link for mux to manage multiple connections (?) 92 * @client: reference to client instance for this connection 93 * @err: error state 94 * @req_lock: lock protecting req_list and requests statuses 95 * @req_list: accounting for requests which have been sent 96 * @unsent_req_list: accounting for requests that haven't been sent 97 * @rreq: read request 98 * @wreq: write request 99 * @tmp_buf: temporary buffer to read in header 100 * @rc: temporary fcall for reading current frame 101 * @wpos: write position for current frame 102 * @wsize: amount of data to write for current frame 103 * @wbuf: current write buffer 104 * @poll_pending_link: pending links to be polled per conn 105 * @poll_wait: array of wait_q's for various worker threads 106 * @pt: poll state 107 * @rq: current read work 108 * @wq: current write work 109 * @wsched: ???? 110 * 111 */ 112 113 struct p9_conn { 114 struct list_head mux_list; 115 struct p9_client *client; 116 int err; 117 spinlock_t req_lock; 118 struct list_head req_list; 119 struct list_head unsent_req_list; 120 struct p9_req_t *rreq; 121 struct p9_req_t *wreq; 122 char tmp_buf[P9_HDRSZ]; 123 struct p9_fcall rc; 124 int wpos; 125 int wsize; 126 char *wbuf; 127 struct list_head poll_pending_link; 128 struct p9_poll_wait poll_wait[MAXPOLLWADDR]; 129 poll_table pt; 130 struct work_struct rq; 131 struct work_struct wq; 132 unsigned long wsched; 133 }; 134 135 /** 136 * struct p9_trans_fd - transport state 137 * @rd: reference to file to read from 138 * @wr: reference of file to write to 139 * @conn: connection state reference 140 * 141 */ 142 143 struct p9_trans_fd { 144 struct file *rd; 145 struct file *wr; 146 struct p9_conn conn; 147 }; 148 149 static void p9_poll_workfn(struct work_struct *work); 150 151 static DEFINE_SPINLOCK(p9_poll_lock); 152 static LIST_HEAD(p9_poll_pending_list); 153 static DECLARE_WORK(p9_poll_work, p9_poll_workfn); 154 155 static unsigned int p9_ipport_resv_min = P9_DEF_MIN_RESVPORT; 156 static unsigned int p9_ipport_resv_max = P9_DEF_MAX_RESVPORT; 157 158 static void p9_mux_poll_stop(struct p9_conn *m) 159 { 160 unsigned long flags; 161 int i; 162 163 for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) { 164 struct p9_poll_wait *pwait = &m->poll_wait[i]; 165 166 if (pwait->wait_addr) { 167 remove_wait_queue(pwait->wait_addr, &pwait->wait); 168 pwait->wait_addr = NULL; 169 } 170 } 171 172 spin_lock_irqsave(&p9_poll_lock, flags); 173 list_del_init(&m->poll_pending_link); 174 spin_unlock_irqrestore(&p9_poll_lock, flags); 175 176 flush_work(&p9_poll_work); 177 } 178 179 /** 180 * p9_conn_cancel - cancel all pending requests with error 181 * @m: mux data 182 * @err: error code 183 * 184 */ 185 186 static void p9_conn_cancel(struct p9_conn *m, int err) 187 { 188 struct p9_req_t *req, *rtmp; 189 LIST_HEAD(cancel_list); 190 191 p9_debug(P9_DEBUG_ERROR, "mux %p err %d\n", m, err); 192 193 spin_lock(&m->req_lock); 194 195 if (READ_ONCE(m->err)) { 196 spin_unlock(&m->req_lock); 197 return; 198 } 199 200 WRITE_ONCE(m->err, err); 201 ASSERT_EXCLUSIVE_WRITER(m->err); 202 203 list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) { 204 list_move(&req->req_list, &cancel_list); 205 WRITE_ONCE(req->status, REQ_STATUS_ERROR); 206 } 207 list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) { 208 list_move(&req->req_list, &cancel_list); 209 WRITE_ONCE(req->status, REQ_STATUS_ERROR); 210 } 211 212 spin_unlock(&m->req_lock); 213 214 list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) { 215 p9_debug(P9_DEBUG_ERROR, "call back req %p\n", req); 216 list_del(&req->req_list); 217 if (!req->t_err) 218 req->t_err = err; 219 p9_client_cb(m->client, req, REQ_STATUS_ERROR); 220 } 221 } 222 223 static __poll_t 224 p9_fd_poll(struct p9_client *client, struct poll_table_struct *pt, int *err) 225 { 226 __poll_t ret; 227 struct p9_trans_fd *ts = NULL; 228 229 if (client && client->status == Connected) 230 ts = client->trans; 231 232 if (!ts) { 233 if (err) 234 *err = -EREMOTEIO; 235 return EPOLLERR; 236 } 237 238 ret = vfs_poll(ts->rd, pt); 239 if (ts->rd != ts->wr) 240 ret = (ret & ~EPOLLOUT) | (vfs_poll(ts->wr, pt) & ~EPOLLIN); 241 return ret; 242 } 243 244 /** 245 * p9_fd_read- read from a fd 246 * @client: client instance 247 * @v: buffer to receive data into 248 * @len: size of receive buffer 249 * 250 */ 251 252 static int p9_fd_read(struct p9_client *client, void *v, int len) 253 { 254 int ret; 255 struct p9_trans_fd *ts = NULL; 256 loff_t pos; 257 258 if (client && client->status != Disconnected) 259 ts = client->trans; 260 261 if (!ts) 262 return -EREMOTEIO; 263 264 if (!(ts->rd->f_flags & O_NONBLOCK)) 265 p9_debug(P9_DEBUG_ERROR, "blocking read ...\n"); 266 267 pos = ts->rd->f_pos; 268 ret = kernel_read(ts->rd, v, len, &pos); 269 if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN) 270 client->status = Disconnected; 271 return ret; 272 } 273 274 /** 275 * p9_read_work - called when there is some data to be read from a transport 276 * @work: container of work to be done 277 * 278 */ 279 280 static void p9_read_work(struct work_struct *work) 281 { 282 __poll_t n; 283 int err; 284 struct p9_conn *m; 285 286 m = container_of(work, struct p9_conn, rq); 287 288 if (READ_ONCE(m->err) < 0) 289 return; 290 291 p9_debug(P9_DEBUG_TRANS, "start mux %p pos %zd\n", m, m->rc.offset); 292 293 if (!m->rc.sdata) { 294 m->rc.sdata = m->tmp_buf; 295 m->rc.offset = 0; 296 m->rc.capacity = P9_HDRSZ; /* start by reading header */ 297 } 298 299 clear_bit(Rpending, &m->wsched); 300 p9_debug(P9_DEBUG_TRANS, "read mux %p pos %zd size: %zd = %zd\n", 301 m, m->rc.offset, m->rc.capacity, 302 m->rc.capacity - m->rc.offset); 303 err = p9_fd_read(m->client, m->rc.sdata + m->rc.offset, 304 m->rc.capacity - m->rc.offset); 305 p9_debug(P9_DEBUG_TRANS, "mux %p got %d bytes\n", m, err); 306 if (err == -EAGAIN) 307 goto end_clear; 308 309 if (err <= 0) 310 goto error; 311 312 m->rc.offset += err; 313 314 /* header read in */ 315 if ((!m->rreq) && (m->rc.offset == m->rc.capacity)) { 316 p9_debug(P9_DEBUG_TRANS, "got new header\n"); 317 318 /* Header size */ 319 m->rc.size = P9_HDRSZ; 320 err = p9_parse_header(&m->rc, &m->rc.size, NULL, NULL, 0); 321 if (err) { 322 p9_debug(P9_DEBUG_ERROR, 323 "error parsing header: %d\n", err); 324 goto error; 325 } 326 327 p9_debug(P9_DEBUG_TRANS, 328 "mux %p pkt: size: %d bytes tag: %d\n", 329 m, m->rc.size, m->rc.tag); 330 331 m->rreq = p9_tag_lookup(m->client, m->rc.tag); 332 if (!m->rreq || (m->rreq->status != REQ_STATUS_SENT)) { 333 p9_debug(P9_DEBUG_ERROR, "Unexpected packet tag %d\n", 334 m->rc.tag); 335 err = -EIO; 336 goto error; 337 } 338 339 if (m->rc.size > m->rreq->rc.capacity) { 340 p9_debug(P9_DEBUG_ERROR, 341 "requested packet size too big: %d for tag %d with capacity %zd\n", 342 m->rc.size, m->rc.tag, m->rreq->rc.capacity); 343 err = -EIO; 344 goto error; 345 } 346 347 if (!m->rreq->rc.sdata) { 348 p9_debug(P9_DEBUG_ERROR, 349 "No recv fcall for tag %d (req %p), disconnecting!\n", 350 m->rc.tag, m->rreq); 351 p9_req_put(m->client, m->rreq); 352 m->rreq = NULL; 353 err = -EIO; 354 goto error; 355 } 356 m->rc.sdata = m->rreq->rc.sdata; 357 memcpy(m->rc.sdata, m->tmp_buf, m->rc.capacity); 358 m->rc.capacity = m->rc.size; 359 } 360 361 /* packet is read in 362 * not an else because some packets (like clunk) have no payload 363 */ 364 if ((m->rreq) && (m->rc.offset == m->rc.capacity)) { 365 p9_debug(P9_DEBUG_TRANS, "got new packet\n"); 366 m->rreq->rc.size = m->rc.offset; 367 spin_lock(&m->req_lock); 368 if (m->rreq->status == REQ_STATUS_SENT) { 369 list_del(&m->rreq->req_list); 370 p9_client_cb(m->client, m->rreq, REQ_STATUS_RCVD); 371 } else if (m->rreq->status == REQ_STATUS_FLSHD) { 372 /* Ignore replies associated with a cancelled request. */ 373 p9_debug(P9_DEBUG_TRANS, 374 "Ignore replies associated with a cancelled request\n"); 375 } else { 376 spin_unlock(&m->req_lock); 377 p9_debug(P9_DEBUG_ERROR, 378 "Request tag %d errored out while we were reading the reply\n", 379 m->rc.tag); 380 err = -EIO; 381 goto error; 382 } 383 spin_unlock(&m->req_lock); 384 m->rc.sdata = NULL; 385 m->rc.offset = 0; 386 m->rc.capacity = 0; 387 p9_req_put(m->client, m->rreq); 388 m->rreq = NULL; 389 } 390 391 end_clear: 392 clear_bit(Rworksched, &m->wsched); 393 394 if (!list_empty(&m->req_list)) { 395 if (test_and_clear_bit(Rpending, &m->wsched)) 396 n = EPOLLIN; 397 else 398 n = p9_fd_poll(m->client, NULL, NULL); 399 400 if ((n & EPOLLIN) && !test_and_set_bit(Rworksched, &m->wsched)) { 401 p9_debug(P9_DEBUG_TRANS, "sched read work %p\n", m); 402 schedule_work(&m->rq); 403 } 404 } 405 406 return; 407 error: 408 p9_conn_cancel(m, err); 409 clear_bit(Rworksched, &m->wsched); 410 } 411 412 /** 413 * p9_fd_write - write to a socket 414 * @client: client instance 415 * @v: buffer to send data from 416 * @len: size of send buffer 417 * 418 */ 419 420 static int p9_fd_write(struct p9_client *client, void *v, int len) 421 { 422 ssize_t ret; 423 struct p9_trans_fd *ts = NULL; 424 425 if (client && client->status != Disconnected) 426 ts = client->trans; 427 428 if (!ts) 429 return -EREMOTEIO; 430 431 if (!(ts->wr->f_flags & O_NONBLOCK)) 432 p9_debug(P9_DEBUG_ERROR, "blocking write ...\n"); 433 434 ret = kernel_write(ts->wr, v, len, &ts->wr->f_pos); 435 if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN) 436 client->status = Disconnected; 437 return ret; 438 } 439 440 /** 441 * p9_write_work - called when a transport can send some data 442 * @work: container for work to be done 443 * 444 */ 445 446 static void p9_write_work(struct work_struct *work) 447 { 448 __poll_t n; 449 int err; 450 struct p9_conn *m; 451 struct p9_req_t *req; 452 453 m = container_of(work, struct p9_conn, wq); 454 455 if (READ_ONCE(m->err) < 0) { 456 clear_bit(Wworksched, &m->wsched); 457 return; 458 } 459 460 if (!m->wsize) { 461 spin_lock(&m->req_lock); 462 if (list_empty(&m->unsent_req_list)) { 463 clear_bit(Wworksched, &m->wsched); 464 spin_unlock(&m->req_lock); 465 return; 466 } 467 468 req = list_entry(m->unsent_req_list.next, struct p9_req_t, 469 req_list); 470 WRITE_ONCE(req->status, REQ_STATUS_SENT); 471 p9_debug(P9_DEBUG_TRANS, "move req %p\n", req); 472 list_move_tail(&req->req_list, &m->req_list); 473 474 m->wbuf = req->tc.sdata; 475 m->wsize = req->tc.size; 476 m->wpos = 0; 477 p9_req_get(req); 478 m->wreq = req; 479 spin_unlock(&m->req_lock); 480 } 481 482 p9_debug(P9_DEBUG_TRANS, "mux %p pos %d size %d\n", 483 m, m->wpos, m->wsize); 484 clear_bit(Wpending, &m->wsched); 485 err = p9_fd_write(m->client, m->wbuf + m->wpos, m->wsize - m->wpos); 486 p9_debug(P9_DEBUG_TRANS, "mux %p sent %d bytes\n", m, err); 487 if (err == -EAGAIN) 488 goto end_clear; 489 490 491 if (err < 0) 492 goto error; 493 else if (err == 0) { 494 err = -EREMOTEIO; 495 goto error; 496 } 497 498 m->wpos += err; 499 if (m->wpos == m->wsize) { 500 m->wpos = m->wsize = 0; 501 p9_req_put(m->client, m->wreq); 502 m->wreq = NULL; 503 } 504 505 end_clear: 506 clear_bit(Wworksched, &m->wsched); 507 508 if (m->wsize || !list_empty(&m->unsent_req_list)) { 509 if (test_and_clear_bit(Wpending, &m->wsched)) 510 n = EPOLLOUT; 511 else 512 n = p9_fd_poll(m->client, NULL, NULL); 513 514 if ((n & EPOLLOUT) && 515 !test_and_set_bit(Wworksched, &m->wsched)) { 516 p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m); 517 schedule_work(&m->wq); 518 } 519 } 520 521 return; 522 523 error: 524 p9_conn_cancel(m, err); 525 clear_bit(Wworksched, &m->wsched); 526 } 527 528 static int p9_pollwake(wait_queue_entry_t *wait, unsigned int mode, int sync, void *key) 529 { 530 struct p9_poll_wait *pwait = 531 container_of(wait, struct p9_poll_wait, wait); 532 struct p9_conn *m = pwait->conn; 533 unsigned long flags; 534 535 spin_lock_irqsave(&p9_poll_lock, flags); 536 if (list_empty(&m->poll_pending_link)) 537 list_add_tail(&m->poll_pending_link, &p9_poll_pending_list); 538 spin_unlock_irqrestore(&p9_poll_lock, flags); 539 540 schedule_work(&p9_poll_work); 541 return 1; 542 } 543 544 /** 545 * p9_pollwait - add poll task to the wait queue 546 * @filp: file pointer being polled 547 * @wait_address: wait_q to block on 548 * @p: poll state 549 * 550 * called by files poll operation to add v9fs-poll task to files wait queue 551 */ 552 553 static void 554 p9_pollwait(struct file *filp, wait_queue_head_t *wait_address, poll_table *p) 555 { 556 struct p9_conn *m = container_of(p, struct p9_conn, pt); 557 struct p9_poll_wait *pwait = NULL; 558 int i; 559 560 for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) { 561 if (m->poll_wait[i].wait_addr == NULL) { 562 pwait = &m->poll_wait[i]; 563 break; 564 } 565 } 566 567 if (!pwait) { 568 p9_debug(P9_DEBUG_ERROR, "not enough wait_address slots\n"); 569 return; 570 } 571 572 pwait->conn = m; 573 pwait->wait_addr = wait_address; 574 init_waitqueue_func_entry(&pwait->wait, p9_pollwake); 575 add_wait_queue(wait_address, &pwait->wait); 576 } 577 578 /** 579 * p9_conn_create - initialize the per-session mux data 580 * @client: client instance 581 * 582 * Note: Creates the polling task if this is the first session. 583 */ 584 585 static void p9_conn_create(struct p9_client *client) 586 { 587 __poll_t n; 588 struct p9_trans_fd *ts = client->trans; 589 struct p9_conn *m = &ts->conn; 590 591 p9_debug(P9_DEBUG_TRANS, "client %p msize %d\n", client, client->msize); 592 593 INIT_LIST_HEAD(&m->mux_list); 594 m->client = client; 595 596 spin_lock_init(&m->req_lock); 597 INIT_LIST_HEAD(&m->req_list); 598 INIT_LIST_HEAD(&m->unsent_req_list); 599 INIT_WORK(&m->rq, p9_read_work); 600 INIT_WORK(&m->wq, p9_write_work); 601 INIT_LIST_HEAD(&m->poll_pending_link); 602 init_poll_funcptr(&m->pt, p9_pollwait); 603 604 n = p9_fd_poll(client, &m->pt, NULL); 605 if (n & EPOLLIN) { 606 p9_debug(P9_DEBUG_TRANS, "mux %p can read\n", m); 607 set_bit(Rpending, &m->wsched); 608 } 609 610 if (n & EPOLLOUT) { 611 p9_debug(P9_DEBUG_TRANS, "mux %p can write\n", m); 612 set_bit(Wpending, &m->wsched); 613 } 614 } 615 616 /** 617 * p9_poll_mux - polls a mux and schedules read or write works if necessary 618 * @m: connection to poll 619 * 620 */ 621 622 static void p9_poll_mux(struct p9_conn *m) 623 { 624 __poll_t n; 625 int err = -ECONNRESET; 626 627 if (READ_ONCE(m->err) < 0) 628 return; 629 630 n = p9_fd_poll(m->client, NULL, &err); 631 if (n & (EPOLLERR | EPOLLHUP | EPOLLNVAL)) { 632 p9_debug(P9_DEBUG_TRANS, "error mux %p err %d\n", m, n); 633 p9_conn_cancel(m, err); 634 } 635 636 if (n & EPOLLIN) { 637 set_bit(Rpending, &m->wsched); 638 p9_debug(P9_DEBUG_TRANS, "mux %p can read\n", m); 639 if (!test_and_set_bit(Rworksched, &m->wsched)) { 640 p9_debug(P9_DEBUG_TRANS, "sched read work %p\n", m); 641 schedule_work(&m->rq); 642 } 643 } 644 645 if (n & EPOLLOUT) { 646 set_bit(Wpending, &m->wsched); 647 p9_debug(P9_DEBUG_TRANS, "mux %p can write\n", m); 648 if ((m->wsize || !list_empty(&m->unsent_req_list)) && 649 !test_and_set_bit(Wworksched, &m->wsched)) { 650 p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m); 651 schedule_work(&m->wq); 652 } 653 } 654 } 655 656 /** 657 * p9_fd_request - send 9P request 658 * The function can sleep until the request is scheduled for sending. 659 * The function can be interrupted. Return from the function is not 660 * a guarantee that the request is sent successfully. 661 * 662 * @client: client instance 663 * @req: request to be sent 664 * 665 */ 666 667 static int p9_fd_request(struct p9_client *client, struct p9_req_t *req) 668 { 669 __poll_t n; 670 int err; 671 struct p9_trans_fd *ts = client->trans; 672 struct p9_conn *m = &ts->conn; 673 674 p9_debug(P9_DEBUG_TRANS, "mux %p task %p tcall %p id %d\n", 675 m, current, &req->tc, req->tc.id); 676 677 spin_lock(&m->req_lock); 678 679 err = READ_ONCE(m->err); 680 if (err < 0) { 681 spin_unlock(&m->req_lock); 682 return err; 683 } 684 685 WRITE_ONCE(req->status, REQ_STATUS_UNSENT); 686 list_add_tail(&req->req_list, &m->unsent_req_list); 687 spin_unlock(&m->req_lock); 688 689 if (test_and_clear_bit(Wpending, &m->wsched)) 690 n = EPOLLOUT; 691 else 692 n = p9_fd_poll(m->client, NULL, NULL); 693 694 if (n & EPOLLOUT && !test_and_set_bit(Wworksched, &m->wsched)) 695 schedule_work(&m->wq); 696 697 return 0; 698 } 699 700 static int p9_fd_cancel(struct p9_client *client, struct p9_req_t *req) 701 { 702 struct p9_trans_fd *ts = client->trans; 703 struct p9_conn *m = &ts->conn; 704 int ret = 1; 705 706 p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req); 707 708 spin_lock(&m->req_lock); 709 710 if (req->status == REQ_STATUS_UNSENT) { 711 list_del(&req->req_list); 712 WRITE_ONCE(req->status, REQ_STATUS_FLSHD); 713 p9_req_put(client, req); 714 ret = 0; 715 } 716 spin_unlock(&m->req_lock); 717 718 return ret; 719 } 720 721 static int p9_fd_cancelled(struct p9_client *client, struct p9_req_t *req) 722 { 723 struct p9_trans_fd *ts = client->trans; 724 struct p9_conn *m = &ts->conn; 725 726 p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req); 727 728 spin_lock(&m->req_lock); 729 /* Ignore cancelled request if message has been received 730 * before lock. 731 */ 732 if (req->status == REQ_STATUS_RCVD) { 733 spin_unlock(&m->req_lock); 734 return 0; 735 } 736 737 /* we haven't received a response for oldreq, 738 * remove it from the list. 739 */ 740 list_del(&req->req_list); 741 WRITE_ONCE(req->status, REQ_STATUS_FLSHD); 742 spin_unlock(&m->req_lock); 743 744 p9_req_put(client, req); 745 746 return 0; 747 } 748 749 static int p9_fd_show_options(struct seq_file *m, struct p9_client *clnt) 750 { 751 if (clnt->trans_mod == &p9_tcp_trans) { 752 if (clnt->trans_opts.tcp.port != P9_PORT) 753 seq_printf(m, ",port=%u", clnt->trans_opts.tcp.port); 754 } else if (clnt->trans_mod == &p9_fd_trans) { 755 if (clnt->trans_opts.fd.rfd != ~0) 756 seq_printf(m, ",rfd=%u", clnt->trans_opts.fd.rfd); 757 if (clnt->trans_opts.fd.wfd != ~0) 758 seq_printf(m, ",wfd=%u", clnt->trans_opts.fd.wfd); 759 } 760 return 0; 761 } 762 763 /** 764 * parse_opts - parse mount options into p9_fd_opts structure 765 * @params: options string passed from mount 766 * @opts: fd transport-specific structure to parse options into 767 * 768 * Returns 0 upon success, -ERRNO upon failure 769 */ 770 771 static int parse_opts(char *params, struct p9_fd_opts *opts) 772 { 773 char *p; 774 substring_t args[MAX_OPT_ARGS]; 775 int option; 776 char *options, *tmp_options; 777 778 opts->port = P9_PORT; 779 opts->rfd = ~0; 780 opts->wfd = ~0; 781 opts->privport = false; 782 783 if (!params) 784 return 0; 785 786 tmp_options = kstrdup(params, GFP_KERNEL); 787 if (!tmp_options) { 788 p9_debug(P9_DEBUG_ERROR, 789 "failed to allocate copy of option string\n"); 790 return -ENOMEM; 791 } 792 options = tmp_options; 793 794 while ((p = strsep(&options, ",")) != NULL) { 795 int token; 796 int r; 797 if (!*p) 798 continue; 799 token = match_token(p, tokens, args); 800 if ((token != Opt_err) && (token != Opt_privport)) { 801 r = match_int(&args[0], &option); 802 if (r < 0) { 803 p9_debug(P9_DEBUG_ERROR, 804 "integer field, but no integer?\n"); 805 continue; 806 } 807 } 808 switch (token) { 809 case Opt_port: 810 opts->port = option; 811 break; 812 case Opt_rfdno: 813 opts->rfd = option; 814 break; 815 case Opt_wfdno: 816 opts->wfd = option; 817 break; 818 case Opt_privport: 819 opts->privport = true; 820 break; 821 default: 822 continue; 823 } 824 } 825 826 kfree(tmp_options); 827 return 0; 828 } 829 830 static int p9_fd_open(struct p9_client *client, int rfd, int wfd) 831 { 832 struct p9_trans_fd *ts = kzalloc(sizeof(struct p9_trans_fd), 833 GFP_KERNEL); 834 if (!ts) 835 return -ENOMEM; 836 837 ts->rd = fget(rfd); 838 if (!ts->rd) 839 goto out_free_ts; 840 if (!(ts->rd->f_mode & FMODE_READ)) 841 goto out_put_rd; 842 /* Prevent workers from hanging on IO when fd is a pipe. 843 * It's technically possible for userspace or concurrent mounts to 844 * modify this flag concurrently, which will likely result in a 845 * broken filesystem. However, just having bad flags here should 846 * not crash the kernel or cause any other sort of bug, so mark this 847 * particular data race as intentional so that tooling (like KCSAN) 848 * can allow it and detect further problems. 849 */ 850 data_race(ts->rd->f_flags |= O_NONBLOCK); 851 ts->wr = fget(wfd); 852 if (!ts->wr) 853 goto out_put_rd; 854 if (!(ts->wr->f_mode & FMODE_WRITE)) 855 goto out_put_wr; 856 data_race(ts->wr->f_flags |= O_NONBLOCK); 857 858 client->trans = ts; 859 client->status = Connected; 860 861 return 0; 862 863 out_put_wr: 864 fput(ts->wr); 865 out_put_rd: 866 fput(ts->rd); 867 out_free_ts: 868 kfree(ts); 869 return -EIO; 870 } 871 872 static int p9_socket_open(struct p9_client *client, struct socket *csocket) 873 { 874 struct p9_trans_fd *p; 875 struct file *file; 876 877 p = kzalloc(sizeof(struct p9_trans_fd), GFP_KERNEL); 878 if (!p) { 879 sock_release(csocket); 880 return -ENOMEM; 881 } 882 883 csocket->sk->sk_allocation = GFP_NOIO; 884 csocket->sk->sk_use_task_frag = false; 885 file = sock_alloc_file(csocket, 0, NULL); 886 if (IS_ERR(file)) { 887 pr_err("%s (%d): failed to map fd\n", 888 __func__, task_pid_nr(current)); 889 kfree(p); 890 return PTR_ERR(file); 891 } 892 893 get_file(file); 894 p->wr = p->rd = file; 895 client->trans = p; 896 client->status = Connected; 897 898 p->rd->f_flags |= O_NONBLOCK; 899 900 p9_conn_create(client); 901 return 0; 902 } 903 904 /** 905 * p9_conn_destroy - cancels all pending requests of mux 906 * @m: mux to destroy 907 * 908 */ 909 910 static void p9_conn_destroy(struct p9_conn *m) 911 { 912 p9_debug(P9_DEBUG_TRANS, "mux %p prev %p next %p\n", 913 m, m->mux_list.prev, m->mux_list.next); 914 915 p9_mux_poll_stop(m); 916 cancel_work_sync(&m->rq); 917 if (m->rreq) { 918 p9_req_put(m->client, m->rreq); 919 m->rreq = NULL; 920 } 921 cancel_work_sync(&m->wq); 922 if (m->wreq) { 923 p9_req_put(m->client, m->wreq); 924 m->wreq = NULL; 925 } 926 927 p9_conn_cancel(m, -ECONNRESET); 928 929 m->client = NULL; 930 } 931 932 /** 933 * p9_fd_close - shutdown file descriptor transport 934 * @client: client instance 935 * 936 */ 937 938 static void p9_fd_close(struct p9_client *client) 939 { 940 struct p9_trans_fd *ts; 941 942 if (!client) 943 return; 944 945 ts = client->trans; 946 if (!ts) 947 return; 948 949 client->status = Disconnected; 950 951 p9_conn_destroy(&ts->conn); 952 953 if (ts->rd) 954 fput(ts->rd); 955 if (ts->wr) 956 fput(ts->wr); 957 958 kfree(ts); 959 } 960 961 static int p9_bind_privport(struct socket *sock) 962 { 963 struct sockaddr_storage stor = { 0 }; 964 int port, err = -EINVAL; 965 966 stor.ss_family = sock->ops->family; 967 if (stor.ss_family == AF_INET) 968 ((struct sockaddr_in *)&stor)->sin_addr.s_addr = htonl(INADDR_ANY); 969 else 970 ((struct sockaddr_in6 *)&stor)->sin6_addr = in6addr_any; 971 for (port = p9_ipport_resv_max; port >= p9_ipport_resv_min; port--) { 972 if (stor.ss_family == AF_INET) 973 ((struct sockaddr_in *)&stor)->sin_port = htons((ushort)port); 974 else 975 ((struct sockaddr_in6 *)&stor)->sin6_port = htons((ushort)port); 976 err = kernel_bind(sock, (struct sockaddr *)&stor, sizeof(stor)); 977 if (err != -EADDRINUSE) 978 break; 979 } 980 return err; 981 } 982 983 static int 984 p9_fd_create_tcp(struct p9_client *client, const char *addr, char *args) 985 { 986 int err; 987 char port_str[6]; 988 struct socket *csocket; 989 struct sockaddr_storage stor = { 0 }; 990 struct p9_fd_opts opts; 991 992 err = parse_opts(args, &opts); 993 if (err < 0) 994 return err; 995 996 if (!addr) 997 return -EINVAL; 998 999 sprintf(port_str, "%u", opts.port); 1000 err = inet_pton_with_scope(current->nsproxy->net_ns, AF_UNSPEC, addr, 1001 port_str, &stor); 1002 if (err < 0) 1003 return err; 1004 1005 csocket = NULL; 1006 1007 client->trans_opts.tcp.port = opts.port; 1008 client->trans_opts.tcp.privport = opts.privport; 1009 err = __sock_create(current->nsproxy->net_ns, stor.ss_family, 1010 SOCK_STREAM, IPPROTO_TCP, &csocket, 1); 1011 if (err) { 1012 pr_err("%s (%d): problem creating socket\n", 1013 __func__, task_pid_nr(current)); 1014 return err; 1015 } 1016 1017 if (opts.privport) { 1018 err = p9_bind_privport(csocket); 1019 if (err < 0) { 1020 pr_err("%s (%d): problem binding to privport\n", 1021 __func__, task_pid_nr(current)); 1022 sock_release(csocket); 1023 return err; 1024 } 1025 } 1026 1027 err = READ_ONCE(csocket->ops)->connect(csocket, 1028 (struct sockaddr *)&stor, 1029 sizeof(stor), 0); 1030 if (err < 0) { 1031 pr_err("%s (%d): problem connecting socket to %s\n", 1032 __func__, task_pid_nr(current), addr); 1033 sock_release(csocket); 1034 return err; 1035 } 1036 1037 return p9_socket_open(client, csocket); 1038 } 1039 1040 static int 1041 p9_fd_create_unix(struct p9_client *client, const char *addr, char *args) 1042 { 1043 int err; 1044 struct socket *csocket; 1045 struct sockaddr_un sun_server; 1046 1047 csocket = NULL; 1048 1049 if (!addr || !strlen(addr)) 1050 return -EINVAL; 1051 1052 if (strlen(addr) >= UNIX_PATH_MAX) { 1053 pr_err("%s (%d): address too long: %s\n", 1054 __func__, task_pid_nr(current), addr); 1055 return -ENAMETOOLONG; 1056 } 1057 1058 sun_server.sun_family = PF_UNIX; 1059 strcpy(sun_server.sun_path, addr); 1060 err = __sock_create(current->nsproxy->net_ns, PF_UNIX, 1061 SOCK_STREAM, 0, &csocket, 1); 1062 if (err < 0) { 1063 pr_err("%s (%d): problem creating socket\n", 1064 __func__, task_pid_nr(current)); 1065 1066 return err; 1067 } 1068 err = READ_ONCE(csocket->ops)->connect(csocket, (struct sockaddr *)&sun_server, 1069 sizeof(struct sockaddr_un) - 1, 0); 1070 if (err < 0) { 1071 pr_err("%s (%d): problem connecting socket: %s: %d\n", 1072 __func__, task_pid_nr(current), addr, err); 1073 sock_release(csocket); 1074 return err; 1075 } 1076 1077 return p9_socket_open(client, csocket); 1078 } 1079 1080 static int 1081 p9_fd_create(struct p9_client *client, const char *addr, char *args) 1082 { 1083 int err; 1084 struct p9_fd_opts opts; 1085 1086 err = parse_opts(args, &opts); 1087 if (err < 0) 1088 return err; 1089 client->trans_opts.fd.rfd = opts.rfd; 1090 client->trans_opts.fd.wfd = opts.wfd; 1091 1092 if (opts.rfd == ~0 || opts.wfd == ~0) { 1093 pr_err("Insufficient options for proto=fd\n"); 1094 return -ENOPROTOOPT; 1095 } 1096 1097 err = p9_fd_open(client, opts.rfd, opts.wfd); 1098 if (err < 0) 1099 return err; 1100 1101 p9_conn_create(client); 1102 1103 return 0; 1104 } 1105 1106 static struct p9_trans_module p9_tcp_trans = { 1107 .name = "tcp", 1108 .maxsize = MAX_SOCK_BUF, 1109 .pooled_rbuffers = false, 1110 .def = 0, 1111 .create = p9_fd_create_tcp, 1112 .close = p9_fd_close, 1113 .request = p9_fd_request, 1114 .cancel = p9_fd_cancel, 1115 .cancelled = p9_fd_cancelled, 1116 .show_options = p9_fd_show_options, 1117 .owner = THIS_MODULE, 1118 }; 1119 MODULE_ALIAS_9P("tcp"); 1120 1121 static struct p9_trans_module p9_unix_trans = { 1122 .name = "unix", 1123 .maxsize = MAX_SOCK_BUF, 1124 .def = 0, 1125 .create = p9_fd_create_unix, 1126 .close = p9_fd_close, 1127 .request = p9_fd_request, 1128 .cancel = p9_fd_cancel, 1129 .cancelled = p9_fd_cancelled, 1130 .show_options = p9_fd_show_options, 1131 .owner = THIS_MODULE, 1132 }; 1133 MODULE_ALIAS_9P("unix"); 1134 1135 static struct p9_trans_module p9_fd_trans = { 1136 .name = "fd", 1137 .maxsize = MAX_SOCK_BUF, 1138 .def = 0, 1139 .create = p9_fd_create, 1140 .close = p9_fd_close, 1141 .request = p9_fd_request, 1142 .cancel = p9_fd_cancel, 1143 .cancelled = p9_fd_cancelled, 1144 .show_options = p9_fd_show_options, 1145 .owner = THIS_MODULE, 1146 }; 1147 MODULE_ALIAS_9P("fd"); 1148 1149 /** 1150 * p9_poll_workfn - poll worker thread 1151 * @work: work queue 1152 * 1153 * polls all v9fs transports for new events and queues the appropriate 1154 * work to the work queue 1155 * 1156 */ 1157 1158 static void p9_poll_workfn(struct work_struct *work) 1159 { 1160 unsigned long flags; 1161 1162 p9_debug(P9_DEBUG_TRANS, "start %p\n", current); 1163 1164 spin_lock_irqsave(&p9_poll_lock, flags); 1165 while (!list_empty(&p9_poll_pending_list)) { 1166 struct p9_conn *conn = list_first_entry(&p9_poll_pending_list, 1167 struct p9_conn, 1168 poll_pending_link); 1169 list_del_init(&conn->poll_pending_link); 1170 spin_unlock_irqrestore(&p9_poll_lock, flags); 1171 1172 p9_poll_mux(conn); 1173 1174 spin_lock_irqsave(&p9_poll_lock, flags); 1175 } 1176 spin_unlock_irqrestore(&p9_poll_lock, flags); 1177 1178 p9_debug(P9_DEBUG_TRANS, "finish\n"); 1179 } 1180 1181 static int __init p9_trans_fd_init(void) 1182 { 1183 v9fs_register_trans(&p9_tcp_trans); 1184 v9fs_register_trans(&p9_unix_trans); 1185 v9fs_register_trans(&p9_fd_trans); 1186 1187 return 0; 1188 } 1189 1190 static void __exit p9_trans_fd_exit(void) 1191 { 1192 flush_work(&p9_poll_work); 1193 v9fs_unregister_trans(&p9_tcp_trans); 1194 v9fs_unregister_trans(&p9_unix_trans); 1195 v9fs_unregister_trans(&p9_fd_trans); 1196 } 1197 1198 module_init(p9_trans_fd_init); 1199 module_exit(p9_trans_fd_exit); 1200 1201 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>"); 1202 MODULE_DESCRIPTION("Filedescriptor Transport for 9P"); 1203 MODULE_LICENSE("GPL"); 1204