1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Fd transport layer. Includes deprecated socket layer. 4 * 5 * Copyright (C) 2006 by Russ Cox <rsc@swtch.com> 6 * Copyright (C) 2004-2005 by Latchesar Ionkov <lucho@ionkov.net> 7 * Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com> 8 * Copyright (C) 1997-2002 by Ron Minnich <rminnich@sarnoff.com> 9 */ 10 11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 12 13 #include <linux/in.h> 14 #include <linux/module.h> 15 #include <linux/net.h> 16 #include <linux/ipv6.h> 17 #include <linux/kthread.h> 18 #include <linux/errno.h> 19 #include <linux/kernel.h> 20 #include <linux/un.h> 21 #include <linux/uaccess.h> 22 #include <linux/inet.h> 23 #include <linux/file.h> 24 #include <linux/parser.h> 25 #include <linux/slab.h> 26 #include <linux/seq_file.h> 27 #include <net/9p/9p.h> 28 #include <net/9p/client.h> 29 #include <net/9p/transport.h> 30 31 #include <linux/syscalls.h> /* killme */ 32 33 #define P9_PORT 564 34 #define MAX_SOCK_BUF (1024*1024) 35 #define MAXPOLLWADDR 2 36 37 static struct p9_trans_module p9_tcp_trans; 38 static struct p9_trans_module p9_fd_trans; 39 40 /** 41 * struct p9_fd_opts - per-transport options 42 * @rfd: file descriptor for reading (trans=fd) 43 * @wfd: file descriptor for writing (trans=fd) 44 * @port: port to connect to (trans=tcp) 45 * @privport: port is privileged 46 */ 47 48 struct p9_fd_opts { 49 int rfd; 50 int wfd; 51 u16 port; 52 bool privport; 53 }; 54 55 /* 56 * Option Parsing (code inspired by NFS code) 57 * - a little lazy - parse all fd-transport options 58 */ 59 60 enum { 61 /* Options that take integer arguments */ 62 Opt_port, Opt_rfdno, Opt_wfdno, Opt_err, 63 /* Options that take no arguments */ 64 Opt_privport, 65 }; 66 67 static const match_table_t tokens = { 68 {Opt_port, "port=%u"}, 69 {Opt_rfdno, "rfdno=%u"}, 70 {Opt_wfdno, "wfdno=%u"}, 71 {Opt_privport, "privport"}, 72 {Opt_err, NULL}, 73 }; 74 75 enum { 76 Rworksched = 1, /* read work scheduled or running */ 77 Rpending = 2, /* can read */ 78 Wworksched = 4, /* write work scheduled or running */ 79 Wpending = 8, /* can write */ 80 }; 81 82 struct p9_poll_wait { 83 struct p9_conn *conn; 84 wait_queue_entry_t wait; 85 wait_queue_head_t *wait_addr; 86 }; 87 88 /** 89 * struct p9_conn - fd mux connection state information 90 * @mux_list: list link for mux to manage multiple connections (?) 91 * @client: reference to client instance for this connection 92 * @err: error state 93 * @req_lock: lock protecting req_list and requests statuses 94 * @req_list: accounting for requests which have been sent 95 * @unsent_req_list: accounting for requests that haven't been sent 96 * @rreq: read request 97 * @wreq: write request 98 * @req: current request being processed (if any) 99 * @tmp_buf: temporary buffer to read in header 100 * @rc: temporary fcall for reading current frame 101 * @wpos: write position for current frame 102 * @wsize: amount of data to write for current frame 103 * @wbuf: current write buffer 104 * @poll_pending_link: pending links to be polled per conn 105 * @poll_wait: array of wait_q's for various worker threads 106 * @pt: poll state 107 * @rq: current read work 108 * @wq: current write work 109 * @wsched: ???? 110 * 111 */ 112 113 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 (m->err) { 196 spin_unlock(&m->req_lock); 197 return; 198 } 199 200 m->err = err; 201 202 list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) { 203 list_move(&req->req_list, &cancel_list); 204 WRITE_ONCE(req->status, REQ_STATUS_ERROR); 205 } 206 list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) { 207 list_move(&req->req_list, &cancel_list); 208 WRITE_ONCE(req->status, REQ_STATUS_ERROR); 209 } 210 211 spin_unlock(&m->req_lock); 212 213 list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) { 214 p9_debug(P9_DEBUG_ERROR, "call back req %p\n", req); 215 list_del(&req->req_list); 216 if (!req->t_err) 217 req->t_err = err; 218 p9_client_cb(m->client, req, REQ_STATUS_ERROR); 219 } 220 } 221 222 static __poll_t 223 p9_fd_poll(struct p9_client *client, struct poll_table_struct *pt, int *err) 224 { 225 __poll_t ret; 226 struct p9_trans_fd *ts = NULL; 227 228 if (client && client->status == Connected) 229 ts = client->trans; 230 231 if (!ts) { 232 if (err) 233 *err = -EREMOTEIO; 234 return EPOLLERR; 235 } 236 237 ret = vfs_poll(ts->rd, pt); 238 if (ts->rd != ts->wr) 239 ret = (ret & ~EPOLLOUT) | (vfs_poll(ts->wr, pt) & ~EPOLLIN); 240 return ret; 241 } 242 243 /** 244 * p9_fd_read- read from a fd 245 * @client: client instance 246 * @v: buffer to receive data into 247 * @len: size of receive buffer 248 * 249 */ 250 251 static int p9_fd_read(struct p9_client *client, void *v, int len) 252 { 253 int ret; 254 struct p9_trans_fd *ts = NULL; 255 loff_t pos; 256 257 if (client && client->status != Disconnected) 258 ts = client->trans; 259 260 if (!ts) 261 return -EREMOTEIO; 262 263 if (!(ts->rd->f_flags & O_NONBLOCK)) 264 p9_debug(P9_DEBUG_ERROR, "blocking read ...\n"); 265 266 pos = ts->rd->f_pos; 267 ret = kernel_read(ts->rd, v, len, &pos); 268 if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN) 269 client->status = Disconnected; 270 return ret; 271 } 272 273 /** 274 * p9_read_work - called when there is some data to be read from a transport 275 * @work: container of work to be done 276 * 277 */ 278 279 static void p9_read_work(struct work_struct *work) 280 { 281 __poll_t n; 282 int err; 283 struct p9_conn *m; 284 285 m = container_of(work, struct p9_conn, rq); 286 287 if (m->err < 0) 288 return; 289 290 p9_debug(P9_DEBUG_TRANS, "start mux %p pos %zd\n", m, m->rc.offset); 291 292 if (!m->rc.sdata) { 293 m->rc.sdata = m->tmp_buf; 294 m->rc.offset = 0; 295 m->rc.capacity = P9_HDRSZ; /* start by reading header */ 296 } 297 298 clear_bit(Rpending, &m->wsched); 299 p9_debug(P9_DEBUG_TRANS, "read mux %p pos %zd size: %zd = %zd\n", 300 m, m->rc.offset, m->rc.capacity, 301 m->rc.capacity - m->rc.offset); 302 err = p9_fd_read(m->client, m->rc.sdata + m->rc.offset, 303 m->rc.capacity - m->rc.offset); 304 p9_debug(P9_DEBUG_TRANS, "mux %p got %d bytes\n", m, err); 305 if (err == -EAGAIN) 306 goto end_clear; 307 308 if (err <= 0) 309 goto error; 310 311 m->rc.offset += err; 312 313 /* header read in */ 314 if ((!m->rreq) && (m->rc.offset == m->rc.capacity)) { 315 p9_debug(P9_DEBUG_TRANS, "got new header\n"); 316 317 /* Header size */ 318 m->rc.size = P9_HDRSZ; 319 err = p9_parse_header(&m->rc, &m->rc.size, NULL, NULL, 0); 320 if (err) { 321 p9_debug(P9_DEBUG_ERROR, 322 "error parsing header: %d\n", err); 323 goto error; 324 } 325 326 p9_debug(P9_DEBUG_TRANS, 327 "mux %p pkt: size: %d bytes tag: %d\n", 328 m, m->rc.size, m->rc.tag); 329 330 m->rreq = p9_tag_lookup(m->client, m->rc.tag); 331 if (!m->rreq || (m->rreq->status != REQ_STATUS_SENT)) { 332 p9_debug(P9_DEBUG_ERROR, "Unexpected packet tag %d\n", 333 m->rc.tag); 334 err = -EIO; 335 goto error; 336 } 337 338 if (m->rc.size > m->rreq->rc.capacity) { 339 p9_debug(P9_DEBUG_ERROR, 340 "requested packet size too big: %d for tag %d with capacity %zd\n", 341 m->rc.size, m->rc.tag, m->rreq->rc.capacity); 342 err = -EIO; 343 goto error; 344 } 345 346 if (!m->rreq->rc.sdata) { 347 p9_debug(P9_DEBUG_ERROR, 348 "No recv fcall for tag %d (req %p), disconnecting!\n", 349 m->rc.tag, m->rreq); 350 p9_req_put(m->client, m->rreq); 351 m->rreq = NULL; 352 err = -EIO; 353 goto error; 354 } 355 m->rc.sdata = m->rreq->rc.sdata; 356 memcpy(m->rc.sdata, m->tmp_buf, m->rc.capacity); 357 m->rc.capacity = m->rc.size; 358 } 359 360 /* packet is read in 361 * not an else because some packets (like clunk) have no payload 362 */ 363 if ((m->rreq) && (m->rc.offset == m->rc.capacity)) { 364 p9_debug(P9_DEBUG_TRANS, "got new packet\n"); 365 m->rreq->rc.size = m->rc.offset; 366 spin_lock(&m->req_lock); 367 if (m->rreq->status == REQ_STATUS_SENT) { 368 list_del(&m->rreq->req_list); 369 p9_client_cb(m->client, m->rreq, REQ_STATUS_RCVD); 370 } else if (m->rreq->status == REQ_STATUS_FLSHD) { 371 /* Ignore replies associated with a cancelled request. */ 372 p9_debug(P9_DEBUG_TRANS, 373 "Ignore replies associated with a cancelled request\n"); 374 } else { 375 spin_unlock(&m->req_lock); 376 p9_debug(P9_DEBUG_ERROR, 377 "Request tag %d errored out while we were reading the reply\n", 378 m->rc.tag); 379 err = -EIO; 380 goto error; 381 } 382 spin_unlock(&m->req_lock); 383 m->rc.sdata = NULL; 384 m->rc.offset = 0; 385 m->rc.capacity = 0; 386 p9_req_put(m->client, m->rreq); 387 m->rreq = NULL; 388 } 389 390 end_clear: 391 clear_bit(Rworksched, &m->wsched); 392 393 if (!list_empty(&m->req_list)) { 394 if (test_and_clear_bit(Rpending, &m->wsched)) 395 n = EPOLLIN; 396 else 397 n = p9_fd_poll(m->client, NULL, NULL); 398 399 if ((n & EPOLLIN) && !test_and_set_bit(Rworksched, &m->wsched)) { 400 p9_debug(P9_DEBUG_TRANS, "sched read work %p\n", m); 401 schedule_work(&m->rq); 402 } 403 } 404 405 return; 406 error: 407 p9_conn_cancel(m, err); 408 clear_bit(Rworksched, &m->wsched); 409 } 410 411 /** 412 * p9_fd_write - write to a socket 413 * @client: client instance 414 * @v: buffer to send data from 415 * @len: size of send buffer 416 * 417 */ 418 419 static int p9_fd_write(struct p9_client *client, void *v, int len) 420 { 421 ssize_t ret; 422 struct p9_trans_fd *ts = NULL; 423 424 if (client && client->status != Disconnected) 425 ts = client->trans; 426 427 if (!ts) 428 return -EREMOTEIO; 429 430 if (!(ts->wr->f_flags & O_NONBLOCK)) 431 p9_debug(P9_DEBUG_ERROR, "blocking write ...\n"); 432 433 ret = kernel_write(ts->wr, v, len, &ts->wr->f_pos); 434 if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN) 435 client->status = Disconnected; 436 return ret; 437 } 438 439 /** 440 * p9_write_work - called when a transport can send some data 441 * @work: container for work to be done 442 * 443 */ 444 445 static void p9_write_work(struct work_struct *work) 446 { 447 __poll_t n; 448 int err; 449 struct p9_conn *m; 450 struct p9_req_t *req; 451 452 m = container_of(work, struct p9_conn, wq); 453 454 if (m->err < 0) { 455 clear_bit(Wworksched, &m->wsched); 456 return; 457 } 458 459 if (!m->wsize) { 460 spin_lock(&m->req_lock); 461 if (list_empty(&m->unsent_req_list)) { 462 clear_bit(Wworksched, &m->wsched); 463 spin_unlock(&m->req_lock); 464 return; 465 } 466 467 req = list_entry(m->unsent_req_list.next, struct p9_req_t, 468 req_list); 469 WRITE_ONCE(req->status, REQ_STATUS_SENT); 470 p9_debug(P9_DEBUG_TRANS, "move req %p\n", req); 471 list_move_tail(&req->req_list, &m->req_list); 472 473 m->wbuf = req->tc.sdata; 474 m->wsize = req->tc.size; 475 m->wpos = 0; 476 p9_req_get(req); 477 m->wreq = req; 478 spin_unlock(&m->req_lock); 479 } 480 481 p9_debug(P9_DEBUG_TRANS, "mux %p pos %d size %d\n", 482 m, m->wpos, m->wsize); 483 clear_bit(Wpending, &m->wsched); 484 err = p9_fd_write(m->client, m->wbuf + m->wpos, m->wsize - m->wpos); 485 p9_debug(P9_DEBUG_TRANS, "mux %p sent %d bytes\n", m, err); 486 if (err == -EAGAIN) 487 goto end_clear; 488 489 490 if (err < 0) 491 goto error; 492 else if (err == 0) { 493 err = -EREMOTEIO; 494 goto error; 495 } 496 497 m->wpos += err; 498 if (m->wpos == m->wsize) { 499 m->wpos = m->wsize = 0; 500 p9_req_put(m->client, m->wreq); 501 m->wreq = NULL; 502 } 503 504 end_clear: 505 clear_bit(Wworksched, &m->wsched); 506 507 if (m->wsize || !list_empty(&m->unsent_req_list)) { 508 if (test_and_clear_bit(Wpending, &m->wsched)) 509 n = EPOLLOUT; 510 else 511 n = p9_fd_poll(m->client, NULL, NULL); 512 513 if ((n & EPOLLOUT) && 514 !test_and_set_bit(Wworksched, &m->wsched)) { 515 p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m); 516 schedule_work(&m->wq); 517 } 518 } 519 520 return; 521 522 error: 523 p9_conn_cancel(m, err); 524 clear_bit(Wworksched, &m->wsched); 525 } 526 527 static int p9_pollwake(wait_queue_entry_t *wait, unsigned int mode, int sync, void *key) 528 { 529 struct p9_poll_wait *pwait = 530 container_of(wait, struct p9_poll_wait, wait); 531 struct p9_conn *m = pwait->conn; 532 unsigned long flags; 533 534 spin_lock_irqsave(&p9_poll_lock, flags); 535 if (list_empty(&m->poll_pending_link)) 536 list_add_tail(&m->poll_pending_link, &p9_poll_pending_list); 537 spin_unlock_irqrestore(&p9_poll_lock, flags); 538 539 schedule_work(&p9_poll_work); 540 return 1; 541 } 542 543 /** 544 * p9_pollwait - add poll task to the wait queue 545 * @filp: file pointer being polled 546 * @wait_address: wait_q to block on 547 * @p: poll state 548 * 549 * called by files poll operation to add v9fs-poll task to files wait queue 550 */ 551 552 static void 553 p9_pollwait(struct file *filp, wait_queue_head_t *wait_address, poll_table *p) 554 { 555 struct p9_conn *m = container_of(p, struct p9_conn, pt); 556 struct p9_poll_wait *pwait = NULL; 557 int i; 558 559 for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) { 560 if (m->poll_wait[i].wait_addr == NULL) { 561 pwait = &m->poll_wait[i]; 562 break; 563 } 564 } 565 566 if (!pwait) { 567 p9_debug(P9_DEBUG_ERROR, "not enough wait_address slots\n"); 568 return; 569 } 570 571 pwait->conn = m; 572 pwait->wait_addr = wait_address; 573 init_waitqueue_func_entry(&pwait->wait, p9_pollwake); 574 add_wait_queue(wait_address, &pwait->wait); 575 } 576 577 /** 578 * p9_conn_create - initialize the per-session mux data 579 * @client: client instance 580 * 581 * Note: Creates the polling task if this is the first session. 582 */ 583 584 static void p9_conn_create(struct p9_client *client) 585 { 586 __poll_t n; 587 struct p9_trans_fd *ts = client->trans; 588 struct p9_conn *m = &ts->conn; 589 590 p9_debug(P9_DEBUG_TRANS, "client %p msize %d\n", client, client->msize); 591 592 INIT_LIST_HEAD(&m->mux_list); 593 m->client = client; 594 595 spin_lock_init(&m->req_lock); 596 INIT_LIST_HEAD(&m->req_list); 597 INIT_LIST_HEAD(&m->unsent_req_list); 598 INIT_WORK(&m->rq, p9_read_work); 599 INIT_WORK(&m->wq, p9_write_work); 600 INIT_LIST_HEAD(&m->poll_pending_link); 601 init_poll_funcptr(&m->pt, p9_pollwait); 602 603 n = p9_fd_poll(client, &m->pt, NULL); 604 if (n & EPOLLIN) { 605 p9_debug(P9_DEBUG_TRANS, "mux %p can read\n", m); 606 set_bit(Rpending, &m->wsched); 607 } 608 609 if (n & EPOLLOUT) { 610 p9_debug(P9_DEBUG_TRANS, "mux %p can write\n", m); 611 set_bit(Wpending, &m->wsched); 612 } 613 } 614 615 /** 616 * p9_poll_mux - polls a mux and schedules read or write works if necessary 617 * @m: connection to poll 618 * 619 */ 620 621 static void p9_poll_mux(struct p9_conn *m) 622 { 623 __poll_t n; 624 int err = -ECONNRESET; 625 626 if (m->err < 0) 627 return; 628 629 n = p9_fd_poll(m->client, NULL, &err); 630 if (n & (EPOLLERR | EPOLLHUP | EPOLLNVAL)) { 631 p9_debug(P9_DEBUG_TRANS, "error mux %p err %d\n", m, n); 632 p9_conn_cancel(m, err); 633 } 634 635 if (n & EPOLLIN) { 636 set_bit(Rpending, &m->wsched); 637 p9_debug(P9_DEBUG_TRANS, "mux %p can read\n", m); 638 if (!test_and_set_bit(Rworksched, &m->wsched)) { 639 p9_debug(P9_DEBUG_TRANS, "sched read work %p\n", m); 640 schedule_work(&m->rq); 641 } 642 } 643 644 if (n & EPOLLOUT) { 645 set_bit(Wpending, &m->wsched); 646 p9_debug(P9_DEBUG_TRANS, "mux %p can write\n", m); 647 if ((m->wsize || !list_empty(&m->unsent_req_list)) && 648 !test_and_set_bit(Wworksched, &m->wsched)) { 649 p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m); 650 schedule_work(&m->wq); 651 } 652 } 653 } 654 655 /** 656 * p9_fd_request - send 9P request 657 * The function can sleep until the request is scheduled for sending. 658 * The function can be interrupted. Return from the function is not 659 * a guarantee that the request is sent successfully. 660 * 661 * @client: client instance 662 * @req: request to be sent 663 * 664 */ 665 666 static int p9_fd_request(struct p9_client *client, struct p9_req_t *req) 667 { 668 __poll_t n; 669 struct p9_trans_fd *ts = client->trans; 670 struct p9_conn *m = &ts->conn; 671 672 p9_debug(P9_DEBUG_TRANS, "mux %p task %p tcall %p id %d\n", 673 m, current, &req->tc, req->tc.id); 674 675 spin_lock(&m->req_lock); 676 677 if (m->err < 0) { 678 spin_unlock(&m->req_lock); 679 return m->err; 680 } 681 682 WRITE_ONCE(req->status, REQ_STATUS_UNSENT); 683 list_add_tail(&req->req_list, &m->unsent_req_list); 684 spin_unlock(&m->req_lock); 685 686 if (test_and_clear_bit(Wpending, &m->wsched)) 687 n = EPOLLOUT; 688 else 689 n = p9_fd_poll(m->client, NULL, NULL); 690 691 if (n & EPOLLOUT && !test_and_set_bit(Wworksched, &m->wsched)) 692 schedule_work(&m->wq); 693 694 return 0; 695 } 696 697 static int p9_fd_cancel(struct p9_client *client, struct p9_req_t *req) 698 { 699 struct p9_trans_fd *ts = client->trans; 700 struct p9_conn *m = &ts->conn; 701 int ret = 1; 702 703 p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req); 704 705 spin_lock(&m->req_lock); 706 707 if (req->status == REQ_STATUS_UNSENT) { 708 list_del(&req->req_list); 709 WRITE_ONCE(req->status, REQ_STATUS_FLSHD); 710 p9_req_put(client, req); 711 ret = 0; 712 } 713 spin_unlock(&m->req_lock); 714 715 return ret; 716 } 717 718 static int p9_fd_cancelled(struct p9_client *client, struct p9_req_t *req) 719 { 720 struct p9_trans_fd *ts = client->trans; 721 struct p9_conn *m = &ts->conn; 722 723 p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req); 724 725 spin_lock(&m->req_lock); 726 /* Ignore cancelled request if message has been received 727 * before lock. 728 */ 729 if (req->status == REQ_STATUS_RCVD) { 730 spin_unlock(&m->req_lock); 731 return 0; 732 } 733 734 /* we haven't received a response for oldreq, 735 * remove it from the list. 736 */ 737 list_del(&req->req_list); 738 WRITE_ONCE(req->status, REQ_STATUS_FLSHD); 739 spin_unlock(&m->req_lock); 740 741 p9_req_put(client, req); 742 743 return 0; 744 } 745 746 static int p9_fd_show_options(struct seq_file *m, struct p9_client *clnt) 747 { 748 if (clnt->trans_mod == &p9_tcp_trans) { 749 if (clnt->trans_opts.tcp.port != P9_PORT) 750 seq_printf(m, ",port=%u", clnt->trans_opts.tcp.port); 751 } else if (clnt->trans_mod == &p9_fd_trans) { 752 if (clnt->trans_opts.fd.rfd != ~0) 753 seq_printf(m, ",rfd=%u", clnt->trans_opts.fd.rfd); 754 if (clnt->trans_opts.fd.wfd != ~0) 755 seq_printf(m, ",wfd=%u", clnt->trans_opts.fd.wfd); 756 } 757 return 0; 758 } 759 760 /** 761 * parse_opts - parse mount options into p9_fd_opts structure 762 * @params: options string passed from mount 763 * @opts: fd transport-specific structure to parse options into 764 * 765 * Returns 0 upon success, -ERRNO upon failure 766 */ 767 768 static int parse_opts(char *params, struct p9_fd_opts *opts) 769 { 770 char *p; 771 substring_t args[MAX_OPT_ARGS]; 772 int option; 773 char *options, *tmp_options; 774 775 opts->port = P9_PORT; 776 opts->rfd = ~0; 777 opts->wfd = ~0; 778 opts->privport = false; 779 780 if (!params) 781 return 0; 782 783 tmp_options = kstrdup(params, GFP_KERNEL); 784 if (!tmp_options) { 785 p9_debug(P9_DEBUG_ERROR, 786 "failed to allocate copy of option string\n"); 787 return -ENOMEM; 788 } 789 options = tmp_options; 790 791 while ((p = strsep(&options, ",")) != NULL) { 792 int token; 793 int r; 794 if (!*p) 795 continue; 796 token = match_token(p, tokens, args); 797 if ((token != Opt_err) && (token != Opt_privport)) { 798 r = match_int(&args[0], &option); 799 if (r < 0) { 800 p9_debug(P9_DEBUG_ERROR, 801 "integer field, but no integer?\n"); 802 continue; 803 } 804 } 805 switch (token) { 806 case Opt_port: 807 opts->port = option; 808 break; 809 case Opt_rfdno: 810 opts->rfd = option; 811 break; 812 case Opt_wfdno: 813 opts->wfd = option; 814 break; 815 case Opt_privport: 816 opts->privport = true; 817 break; 818 default: 819 continue; 820 } 821 } 822 823 kfree(tmp_options); 824 return 0; 825 } 826 827 static int p9_fd_open(struct p9_client *client, int rfd, int wfd) 828 { 829 struct p9_trans_fd *ts = kzalloc(sizeof(struct p9_trans_fd), 830 GFP_KERNEL); 831 if (!ts) 832 return -ENOMEM; 833 834 ts->rd = fget(rfd); 835 if (!ts->rd) 836 goto out_free_ts; 837 if (!(ts->rd->f_mode & FMODE_READ)) 838 goto out_put_rd; 839 /* Prevent workers from hanging on IO when fd is a pipe. 840 * It's technically possible for userspace or concurrent mounts to 841 * modify this flag concurrently, which will likely result in a 842 * broken filesystem. However, just having bad flags here should 843 * not crash the kernel or cause any other sort of bug, so mark this 844 * particular data race as intentional so that tooling (like KCSAN) 845 * can allow it and detect further problems. 846 */ 847 data_race(ts->rd->f_flags |= O_NONBLOCK); 848 ts->wr = fget(wfd); 849 if (!ts->wr) 850 goto out_put_rd; 851 if (!(ts->wr->f_mode & FMODE_WRITE)) 852 goto out_put_wr; 853 data_race(ts->wr->f_flags |= O_NONBLOCK); 854 855 client->trans = ts; 856 client->status = Connected; 857 858 return 0; 859 860 out_put_wr: 861 fput(ts->wr); 862 out_put_rd: 863 fput(ts->rd); 864 out_free_ts: 865 kfree(ts); 866 return -EIO; 867 } 868 869 static int p9_socket_open(struct p9_client *client, struct socket *csocket) 870 { 871 struct p9_trans_fd *p; 872 struct file *file; 873 874 p = kzalloc(sizeof(struct p9_trans_fd), GFP_KERNEL); 875 if (!p) { 876 sock_release(csocket); 877 return -ENOMEM; 878 } 879 880 csocket->sk->sk_allocation = GFP_NOIO; 881 csocket->sk->sk_use_task_frag = false; 882 file = sock_alloc_file(csocket, 0, NULL); 883 if (IS_ERR(file)) { 884 pr_err("%s (%d): failed to map fd\n", 885 __func__, task_pid_nr(current)); 886 kfree(p); 887 return PTR_ERR(file); 888 } 889 890 get_file(file); 891 p->wr = p->rd = file; 892 client->trans = p; 893 client->status = Connected; 894 895 p->rd->f_flags |= O_NONBLOCK; 896 897 p9_conn_create(client); 898 return 0; 899 } 900 901 /** 902 * p9_conn_destroy - cancels all pending requests of mux 903 * @m: mux to destroy 904 * 905 */ 906 907 static void p9_conn_destroy(struct p9_conn *m) 908 { 909 p9_debug(P9_DEBUG_TRANS, "mux %p prev %p next %p\n", 910 m, m->mux_list.prev, m->mux_list.next); 911 912 p9_mux_poll_stop(m); 913 cancel_work_sync(&m->rq); 914 if (m->rreq) { 915 p9_req_put(m->client, m->rreq); 916 m->rreq = NULL; 917 } 918 cancel_work_sync(&m->wq); 919 if (m->wreq) { 920 p9_req_put(m->client, m->wreq); 921 m->wreq = NULL; 922 } 923 924 p9_conn_cancel(m, -ECONNRESET); 925 926 m->client = NULL; 927 } 928 929 /** 930 * p9_fd_close - shutdown file descriptor transport 931 * @client: client instance 932 * 933 */ 934 935 static void p9_fd_close(struct p9_client *client) 936 { 937 struct p9_trans_fd *ts; 938 939 if (!client) 940 return; 941 942 ts = client->trans; 943 if (!ts) 944 return; 945 946 client->status = Disconnected; 947 948 p9_conn_destroy(&ts->conn); 949 950 if (ts->rd) 951 fput(ts->rd); 952 if (ts->wr) 953 fput(ts->wr); 954 955 kfree(ts); 956 } 957 958 /* 959 * stolen from NFS - maybe should be made a generic function? 960 */ 961 static inline int valid_ipaddr4(const char *buf) 962 { 963 int rc, count, in[4]; 964 965 rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]); 966 if (rc != 4) 967 return -EINVAL; 968 for (count = 0; count < 4; count++) { 969 if (in[count] > 255) 970 return -EINVAL; 971 } 972 return 0; 973 } 974 975 static int p9_bind_privport(struct socket *sock) 976 { 977 struct sockaddr_in cl; 978 int port, err = -EINVAL; 979 980 memset(&cl, 0, sizeof(cl)); 981 cl.sin_family = AF_INET; 982 cl.sin_addr.s_addr = htonl(INADDR_ANY); 983 for (port = p9_ipport_resv_max; port >= p9_ipport_resv_min; port--) { 984 cl.sin_port = htons((ushort)port); 985 err = kernel_bind(sock, (struct sockaddr *)&cl, sizeof(cl)); 986 if (err != -EADDRINUSE) 987 break; 988 } 989 return err; 990 } 991 992 993 static int 994 p9_fd_create_tcp(struct p9_client *client, const char *addr, char *args) 995 { 996 int err; 997 struct socket *csocket; 998 struct sockaddr_in sin_server; 999 struct p9_fd_opts opts; 1000 1001 err = parse_opts(args, &opts); 1002 if (err < 0) 1003 return err; 1004 1005 if (addr == NULL || valid_ipaddr4(addr) < 0) 1006 return -EINVAL; 1007 1008 csocket = NULL; 1009 1010 client->trans_opts.tcp.port = opts.port; 1011 client->trans_opts.tcp.privport = opts.privport; 1012 sin_server.sin_family = AF_INET; 1013 sin_server.sin_addr.s_addr = in_aton(addr); 1014 sin_server.sin_port = htons(opts.port); 1015 err = __sock_create(current->nsproxy->net_ns, PF_INET, 1016 SOCK_STREAM, IPPROTO_TCP, &csocket, 1); 1017 if (err) { 1018 pr_err("%s (%d): problem creating socket\n", 1019 __func__, task_pid_nr(current)); 1020 return err; 1021 } 1022 1023 if (opts.privport) { 1024 err = p9_bind_privport(csocket); 1025 if (err < 0) { 1026 pr_err("%s (%d): problem binding to privport\n", 1027 __func__, task_pid_nr(current)); 1028 sock_release(csocket); 1029 return err; 1030 } 1031 } 1032 1033 err = READ_ONCE(csocket->ops)->connect(csocket, 1034 (struct sockaddr *)&sin_server, 1035 sizeof(struct sockaddr_in), 0); 1036 if (err < 0) { 1037 pr_err("%s (%d): problem connecting socket to %s\n", 1038 __func__, task_pid_nr(current), addr); 1039 sock_release(csocket); 1040 return err; 1041 } 1042 1043 return p9_socket_open(client, csocket); 1044 } 1045 1046 static int 1047 p9_fd_create_unix(struct p9_client *client, const char *addr, char *args) 1048 { 1049 int err; 1050 struct socket *csocket; 1051 struct sockaddr_un sun_server; 1052 1053 csocket = NULL; 1054 1055 if (!addr || !strlen(addr)) 1056 return -EINVAL; 1057 1058 if (strlen(addr) >= UNIX_PATH_MAX) { 1059 pr_err("%s (%d): address too long: %s\n", 1060 __func__, task_pid_nr(current), addr); 1061 return -ENAMETOOLONG; 1062 } 1063 1064 sun_server.sun_family = PF_UNIX; 1065 strcpy(sun_server.sun_path, addr); 1066 err = __sock_create(current->nsproxy->net_ns, PF_UNIX, 1067 SOCK_STREAM, 0, &csocket, 1); 1068 if (err < 0) { 1069 pr_err("%s (%d): problem creating socket\n", 1070 __func__, task_pid_nr(current)); 1071 1072 return err; 1073 } 1074 err = READ_ONCE(csocket->ops)->connect(csocket, (struct sockaddr *)&sun_server, 1075 sizeof(struct sockaddr_un) - 1, 0); 1076 if (err < 0) { 1077 pr_err("%s (%d): problem connecting socket: %s: %d\n", 1078 __func__, task_pid_nr(current), addr, err); 1079 sock_release(csocket); 1080 return err; 1081 } 1082 1083 return p9_socket_open(client, csocket); 1084 } 1085 1086 static int 1087 p9_fd_create(struct p9_client *client, const char *addr, char *args) 1088 { 1089 int err; 1090 struct p9_fd_opts opts; 1091 1092 err = parse_opts(args, &opts); 1093 if (err < 0) 1094 return err; 1095 client->trans_opts.fd.rfd = opts.rfd; 1096 client->trans_opts.fd.wfd = opts.wfd; 1097 1098 if (opts.rfd == ~0 || opts.wfd == ~0) { 1099 pr_err("Insufficient options for proto=fd\n"); 1100 return -ENOPROTOOPT; 1101 } 1102 1103 err = p9_fd_open(client, opts.rfd, opts.wfd); 1104 if (err < 0) 1105 return err; 1106 1107 p9_conn_create(client); 1108 1109 return 0; 1110 } 1111 1112 static struct p9_trans_module p9_tcp_trans = { 1113 .name = "tcp", 1114 .maxsize = MAX_SOCK_BUF, 1115 .pooled_rbuffers = false, 1116 .def = 0, 1117 .create = p9_fd_create_tcp, 1118 .close = p9_fd_close, 1119 .request = p9_fd_request, 1120 .cancel = p9_fd_cancel, 1121 .cancelled = p9_fd_cancelled, 1122 .show_options = p9_fd_show_options, 1123 .owner = THIS_MODULE, 1124 }; 1125 MODULE_ALIAS_9P("tcp"); 1126 1127 static struct p9_trans_module p9_unix_trans = { 1128 .name = "unix", 1129 .maxsize = MAX_SOCK_BUF, 1130 .def = 0, 1131 .create = p9_fd_create_unix, 1132 .close = p9_fd_close, 1133 .request = p9_fd_request, 1134 .cancel = p9_fd_cancel, 1135 .cancelled = p9_fd_cancelled, 1136 .show_options = p9_fd_show_options, 1137 .owner = THIS_MODULE, 1138 }; 1139 MODULE_ALIAS_9P("unix"); 1140 1141 static struct p9_trans_module p9_fd_trans = { 1142 .name = "fd", 1143 .maxsize = MAX_SOCK_BUF, 1144 .def = 0, 1145 .create = p9_fd_create, 1146 .close = p9_fd_close, 1147 .request = p9_fd_request, 1148 .cancel = p9_fd_cancel, 1149 .cancelled = p9_fd_cancelled, 1150 .show_options = p9_fd_show_options, 1151 .owner = THIS_MODULE, 1152 }; 1153 MODULE_ALIAS_9P("fd"); 1154 1155 /** 1156 * p9_poll_workfn - poll worker thread 1157 * @work: work queue 1158 * 1159 * polls all v9fs transports for new events and queues the appropriate 1160 * work to the work queue 1161 * 1162 */ 1163 1164 static void p9_poll_workfn(struct work_struct *work) 1165 { 1166 unsigned long flags; 1167 1168 p9_debug(P9_DEBUG_TRANS, "start %p\n", current); 1169 1170 spin_lock_irqsave(&p9_poll_lock, flags); 1171 while (!list_empty(&p9_poll_pending_list)) { 1172 struct p9_conn *conn = list_first_entry(&p9_poll_pending_list, 1173 struct p9_conn, 1174 poll_pending_link); 1175 list_del_init(&conn->poll_pending_link); 1176 spin_unlock_irqrestore(&p9_poll_lock, flags); 1177 1178 p9_poll_mux(conn); 1179 1180 spin_lock_irqsave(&p9_poll_lock, flags); 1181 } 1182 spin_unlock_irqrestore(&p9_poll_lock, flags); 1183 1184 p9_debug(P9_DEBUG_TRANS, "finish\n"); 1185 } 1186 1187 static int __init p9_trans_fd_init(void) 1188 { 1189 v9fs_register_trans(&p9_tcp_trans); 1190 v9fs_register_trans(&p9_unix_trans); 1191 v9fs_register_trans(&p9_fd_trans); 1192 1193 return 0; 1194 } 1195 1196 static void __exit p9_trans_fd_exit(void) 1197 { 1198 flush_work(&p9_poll_work); 1199 v9fs_unregister_trans(&p9_tcp_trans); 1200 v9fs_unregister_trans(&p9_unix_trans); 1201 v9fs_unregister_trans(&p9_fd_trans); 1202 } 1203 1204 module_init(p9_trans_fd_init); 1205 module_exit(p9_trans_fd_exit); 1206 1207 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>"); 1208 MODULE_DESCRIPTION("Filedescriptor Transport for 9P"); 1209 MODULE_LICENSE("GPL"); 1210