1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Fd transport layer. Includes deprecated socket layer. 4 * 5 * Copyright (C) 2006 by Russ Cox <rsc@swtch.com> 6 * Copyright (C) 2004-2005 by Latchesar Ionkov <lucho@ionkov.net> 7 * Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com> 8 * Copyright (C) 1997-2002 by Ron Minnich <rminnich@sarnoff.com> 9 */ 10 11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 12 13 #include <linux/in.h> 14 #include <linux/in6.h> 15 #include <linux/module.h> 16 #include <linux/net.h> 17 #include <linux/ipv6.h> 18 #include <linux/kthread.h> 19 #include <linux/errno.h> 20 #include <linux/kernel.h> 21 #include <linux/un.h> 22 #include <linux/uaccess.h> 23 #include <linux/inet.h> 24 #include <linux/file.h> 25 #include <linux/fs_context.h> 26 #include <linux/slab.h> 27 #include <linux/seq_file.h> 28 #include <net/9p/9p.h> 29 #include <net/9p/client.h> 30 #include <net/9p/transport.h> 31 32 #include <linux/syscalls.h> /* killme */ 33 34 #define MAX_SOCK_BUF (1024*1024) 35 #define MAXPOLLWADDR 2 36 37 static struct p9_trans_module p9_tcp_trans; 38 static struct p9_trans_module p9_fd_trans; 39 40 enum { 41 Rworksched = 1, /* read work scheduled or running */ 42 Rpending = 2, /* can read */ 43 Wworksched = 4, /* write work scheduled or running */ 44 Wpending = 8, /* can write */ 45 }; 46 47 struct p9_poll_wait { 48 struct p9_conn *conn; 49 wait_queue_entry_t wait; 50 wait_queue_head_t *wait_addr; 51 }; 52 53 /** 54 * struct p9_conn - fd mux connection state information 55 * @mux_list: list link for mux to manage multiple connections (?) 56 * @client: reference to client instance for this connection 57 * @err: error state 58 * @req_lock: lock protecting req_list and requests statuses 59 * @req_list: accounting for requests which have been sent 60 * @unsent_req_list: accounting for requests that haven't been sent 61 * @rreq: read request 62 * @wreq: write request 63 * @tmp_buf: temporary buffer to read in header 64 * @rc: temporary fcall for reading current frame 65 * @wpos: write position for current frame 66 * @wsize: amount of data to write for current frame 67 * @wbuf: current write buffer 68 * @poll_pending_link: pending links to be polled per conn 69 * @poll_wait: array of wait_q's for various worker threads 70 * @pt: poll state 71 * @rq: current read work 72 * @wq: current write work 73 * @wsched: ???? 74 * 75 */ 76 77 struct p9_conn { 78 struct list_head mux_list; 79 struct p9_client *client; 80 int err; 81 spinlock_t req_lock; 82 struct list_head req_list; 83 struct list_head unsent_req_list; 84 struct p9_req_t *rreq; 85 struct p9_req_t *wreq; 86 char tmp_buf[P9_HDRSZ]; 87 struct p9_fcall rc; 88 int wpos; 89 int wsize; 90 char *wbuf; 91 struct list_head poll_pending_link; 92 struct p9_poll_wait poll_wait[MAXPOLLWADDR]; 93 poll_table pt; 94 struct work_struct rq; 95 struct work_struct wq; 96 unsigned long wsched; 97 }; 98 99 /** 100 * struct p9_trans_fd - transport state 101 * @rd: reference to file to read from 102 * @wr: reference of file to write to 103 * @conn: connection state reference 104 * 105 */ 106 107 struct p9_trans_fd { 108 struct file *rd; 109 struct file *wr; 110 struct p9_conn conn; 111 }; 112 113 static void p9_poll_workfn(struct work_struct *work); 114 115 static DEFINE_SPINLOCK(p9_poll_lock); 116 static LIST_HEAD(p9_poll_pending_list); 117 static DECLARE_WORK(p9_poll_work, p9_poll_workfn); 118 119 static unsigned int p9_ipport_resv_min = P9_DEF_MIN_RESVPORT; 120 static unsigned int p9_ipport_resv_max = P9_DEF_MAX_RESVPORT; 121 122 static void p9_mux_poll_stop(struct p9_conn *m) 123 { 124 unsigned long flags; 125 int i; 126 127 for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) { 128 struct p9_poll_wait *pwait = &m->poll_wait[i]; 129 130 if (pwait->wait_addr) { 131 remove_wait_queue(pwait->wait_addr, &pwait->wait); 132 pwait->wait_addr = NULL; 133 } 134 } 135 136 spin_lock_irqsave(&p9_poll_lock, flags); 137 list_del_init(&m->poll_pending_link); 138 spin_unlock_irqrestore(&p9_poll_lock, flags); 139 140 flush_work(&p9_poll_work); 141 } 142 143 /** 144 * p9_conn_cancel - cancel all pending requests with error 145 * @m: mux data 146 * @err: error code 147 * 148 */ 149 150 static void p9_conn_cancel(struct p9_conn *m, int err) 151 { 152 struct p9_req_t *req, *rtmp; 153 LIST_HEAD(cancel_list); 154 155 p9_debug(P9_DEBUG_ERROR, "mux %p err %d\n", m, err); 156 157 spin_lock(&m->req_lock); 158 159 if (READ_ONCE(m->err)) { 160 spin_unlock(&m->req_lock); 161 return; 162 } 163 164 WRITE_ONCE(m->err, err); 165 ASSERT_EXCLUSIVE_WRITER(m->err); 166 167 list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) { 168 list_move(&req->req_list, &cancel_list); 169 WRITE_ONCE(req->status, REQ_STATUS_ERROR); 170 } 171 list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) { 172 list_move(&req->req_list, &cancel_list); 173 WRITE_ONCE(req->status, REQ_STATUS_ERROR); 174 } 175 176 spin_unlock(&m->req_lock); 177 178 list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) { 179 p9_debug(P9_DEBUG_ERROR, "call back req %p\n", req); 180 list_del(&req->req_list); 181 if (!req->t_err) 182 req->t_err = err; 183 p9_client_cb(m->client, req, REQ_STATUS_ERROR); 184 } 185 } 186 187 static __poll_t 188 p9_fd_poll(struct p9_client *client, struct poll_table_struct *pt, int *err) 189 { 190 __poll_t ret; 191 struct p9_trans_fd *ts = NULL; 192 193 if (client && client->status == Connected) 194 ts = client->trans; 195 196 if (!ts) { 197 if (err) 198 *err = -EREMOTEIO; 199 return EPOLLERR; 200 } 201 202 ret = vfs_poll(ts->rd, pt); 203 if (ts->rd != ts->wr) 204 ret = (ret & ~EPOLLOUT) | (vfs_poll(ts->wr, pt) & ~EPOLLIN); 205 return ret; 206 } 207 208 /** 209 * p9_fd_read- read from a fd 210 * @client: client instance 211 * @v: buffer to receive data into 212 * @len: size of receive buffer 213 * 214 */ 215 216 static int p9_fd_read(struct p9_client *client, void *v, int len) 217 { 218 int ret; 219 struct p9_trans_fd *ts = NULL; 220 loff_t pos; 221 222 if (client && client->status != Disconnected) 223 ts = client->trans; 224 225 if (!ts) 226 return -EREMOTEIO; 227 228 if (!(ts->rd->f_flags & O_NONBLOCK)) 229 p9_debug(P9_DEBUG_ERROR, "blocking read ...\n"); 230 231 pos = ts->rd->f_pos; 232 ret = kernel_read(ts->rd, v, len, &pos); 233 if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN) 234 client->status = Disconnected; 235 return ret; 236 } 237 238 /** 239 * p9_read_work - called when there is some data to be read from a transport 240 * @work: container of work to be done 241 * 242 */ 243 244 static void p9_read_work(struct work_struct *work) 245 { 246 __poll_t n; 247 int err; 248 struct p9_conn *m; 249 250 m = container_of(work, struct p9_conn, rq); 251 252 if (READ_ONCE(m->err) < 0) 253 return; 254 255 p9_debug(P9_DEBUG_TRANS, "start mux %p pos %zd\n", m, m->rc.offset); 256 257 if (!m->rc.sdata) { 258 m->rc.sdata = m->tmp_buf; 259 m->rc.offset = 0; 260 m->rc.capacity = P9_HDRSZ; /* start by reading header */ 261 } 262 263 clear_bit(Rpending, &m->wsched); 264 p9_debug(P9_DEBUG_TRANS, "read mux %p pos %zd size: %zd = %zd\n", 265 m, m->rc.offset, m->rc.capacity, 266 m->rc.capacity - m->rc.offset); 267 err = p9_fd_read(m->client, m->rc.sdata + m->rc.offset, 268 m->rc.capacity - m->rc.offset); 269 p9_debug(P9_DEBUG_TRANS, "mux %p got %d bytes\n", m, err); 270 if (err == -EAGAIN) 271 goto end_clear; 272 273 if (err <= 0) 274 goto error; 275 276 m->rc.offset += err; 277 278 /* header read in */ 279 if ((!m->rreq) && (m->rc.offset == m->rc.capacity)) { 280 p9_debug(P9_DEBUG_TRANS, "got new header\n"); 281 282 /* Header size */ 283 m->rc.size = P9_HDRSZ; 284 err = p9_parse_header(&m->rc, &m->rc.size, NULL, NULL, 0); 285 if (err) { 286 p9_debug(P9_DEBUG_ERROR, 287 "error parsing header: %d\n", err); 288 goto error; 289 } 290 291 p9_debug(P9_DEBUG_TRANS, 292 "mux %p pkt: size: %d bytes tag: %d\n", 293 m, m->rc.size, m->rc.tag); 294 295 m->rreq = p9_tag_lookup(m->client, m->rc.tag); 296 if (!m->rreq || (m->rreq->status != REQ_STATUS_SENT)) { 297 p9_debug(P9_DEBUG_ERROR, "Unexpected packet tag %d\n", 298 m->rc.tag); 299 err = -EIO; 300 goto error; 301 } 302 303 if (m->rc.size > m->rreq->rc.capacity) { 304 p9_debug(P9_DEBUG_ERROR, 305 "requested packet size too big: %d for tag %d with capacity %zd\n", 306 m->rc.size, m->rc.tag, m->rreq->rc.capacity); 307 err = -EIO; 308 goto error; 309 } 310 311 if (!m->rreq->rc.sdata) { 312 p9_debug(P9_DEBUG_ERROR, 313 "No recv fcall for tag %d (req %p), disconnecting!\n", 314 m->rc.tag, m->rreq); 315 p9_req_put(m->client, m->rreq); 316 m->rreq = NULL; 317 err = -EIO; 318 goto error; 319 } 320 m->rc.sdata = m->rreq->rc.sdata; 321 memcpy(m->rc.sdata, m->tmp_buf, m->rc.capacity); 322 m->rc.capacity = m->rc.size; 323 } 324 325 /* packet is read in 326 * not an else because some packets (like clunk) have no payload 327 */ 328 if ((m->rreq) && (m->rc.offset == m->rc.capacity)) { 329 p9_debug(P9_DEBUG_TRANS, "got new packet\n"); 330 m->rreq->rc.size = m->rc.offset; 331 spin_lock(&m->req_lock); 332 if (m->rreq->status == REQ_STATUS_SENT) { 333 list_del(&m->rreq->req_list); 334 p9_client_cb(m->client, m->rreq, REQ_STATUS_RCVD); 335 } else if (m->rreq->status == REQ_STATUS_FLSHD) { 336 /* Ignore replies associated with a cancelled request. */ 337 p9_debug(P9_DEBUG_TRANS, 338 "Ignore replies associated with a cancelled request\n"); 339 } else { 340 spin_unlock(&m->req_lock); 341 p9_debug(P9_DEBUG_ERROR, 342 "Request tag %d errored out while we were reading the reply\n", 343 m->rc.tag); 344 err = -EIO; 345 goto error; 346 } 347 spin_unlock(&m->req_lock); 348 m->rc.sdata = NULL; 349 m->rc.offset = 0; 350 m->rc.capacity = 0; 351 p9_req_put(m->client, m->rreq); 352 m->rreq = NULL; 353 } 354 355 end_clear: 356 clear_bit(Rworksched, &m->wsched); 357 358 if (!list_empty(&m->req_list)) { 359 if (test_and_clear_bit(Rpending, &m->wsched)) 360 n = EPOLLIN; 361 else 362 n = p9_fd_poll(m->client, NULL, NULL); 363 364 if ((n & EPOLLIN) && !test_and_set_bit(Rworksched, &m->wsched)) { 365 p9_debug(P9_DEBUG_TRANS, "sched read work %p\n", m); 366 schedule_work(&m->rq); 367 } 368 } 369 370 return; 371 error: 372 p9_conn_cancel(m, err); 373 clear_bit(Rworksched, &m->wsched); 374 } 375 376 /** 377 * p9_fd_write - write to a socket 378 * @client: client instance 379 * @v: buffer to send data from 380 * @len: size of send buffer 381 * 382 */ 383 384 static int p9_fd_write(struct p9_client *client, void *v, int len) 385 { 386 ssize_t ret; 387 struct p9_trans_fd *ts = NULL; 388 389 if (client && client->status != Disconnected) 390 ts = client->trans; 391 392 if (!ts) 393 return -EREMOTEIO; 394 395 if (!(ts->wr->f_flags & O_NONBLOCK)) 396 p9_debug(P9_DEBUG_ERROR, "blocking write ...\n"); 397 398 ret = kernel_write(ts->wr, v, len, &ts->wr->f_pos); 399 if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN) 400 client->status = Disconnected; 401 return ret; 402 } 403 404 /** 405 * p9_write_work - called when a transport can send some data 406 * @work: container for work to be done 407 * 408 */ 409 410 static void p9_write_work(struct work_struct *work) 411 { 412 __poll_t n; 413 int err; 414 struct p9_conn *m; 415 struct p9_req_t *req; 416 417 m = container_of(work, struct p9_conn, wq); 418 419 if (READ_ONCE(m->err) < 0) { 420 clear_bit(Wworksched, &m->wsched); 421 return; 422 } 423 424 if (!m->wsize) { 425 spin_lock(&m->req_lock); 426 if (list_empty(&m->unsent_req_list)) { 427 clear_bit(Wworksched, &m->wsched); 428 spin_unlock(&m->req_lock); 429 return; 430 } 431 432 req = list_entry(m->unsent_req_list.next, struct p9_req_t, 433 req_list); 434 WRITE_ONCE(req->status, REQ_STATUS_SENT); 435 p9_debug(P9_DEBUG_TRANS, "move req %p\n", req); 436 list_move_tail(&req->req_list, &m->req_list); 437 438 m->wbuf = req->tc.sdata; 439 m->wsize = req->tc.size; 440 m->wpos = 0; 441 p9_req_get(req); 442 m->wreq = req; 443 spin_unlock(&m->req_lock); 444 } 445 446 p9_debug(P9_DEBUG_TRANS, "mux %p pos %d size %d\n", 447 m, m->wpos, m->wsize); 448 clear_bit(Wpending, &m->wsched); 449 err = p9_fd_write(m->client, m->wbuf + m->wpos, m->wsize - m->wpos); 450 p9_debug(P9_DEBUG_TRANS, "mux %p sent %d bytes\n", m, err); 451 if (err == -EAGAIN) 452 goto end_clear; 453 454 455 if (err < 0) 456 goto error; 457 else if (err == 0) { 458 err = -EREMOTEIO; 459 goto error; 460 } 461 462 m->wpos += err; 463 if (m->wpos == m->wsize) { 464 m->wpos = m->wsize = 0; 465 p9_req_put(m->client, m->wreq); 466 m->wreq = NULL; 467 } 468 469 end_clear: 470 clear_bit(Wworksched, &m->wsched); 471 472 if (m->wsize || !list_empty(&m->unsent_req_list)) { 473 if (test_and_clear_bit(Wpending, &m->wsched)) 474 n = EPOLLOUT; 475 else 476 n = p9_fd_poll(m->client, NULL, NULL); 477 478 if ((n & EPOLLOUT) && 479 !test_and_set_bit(Wworksched, &m->wsched)) { 480 p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m); 481 schedule_work(&m->wq); 482 } 483 } 484 485 return; 486 487 error: 488 p9_conn_cancel(m, err); 489 clear_bit(Wworksched, &m->wsched); 490 } 491 492 static int p9_pollwake(wait_queue_entry_t *wait, unsigned int mode, int sync, void *key) 493 { 494 struct p9_poll_wait *pwait = 495 container_of(wait, struct p9_poll_wait, wait); 496 struct p9_conn *m = pwait->conn; 497 unsigned long flags; 498 499 spin_lock_irqsave(&p9_poll_lock, flags); 500 if (list_empty(&m->poll_pending_link)) 501 list_add_tail(&m->poll_pending_link, &p9_poll_pending_list); 502 spin_unlock_irqrestore(&p9_poll_lock, flags); 503 504 schedule_work(&p9_poll_work); 505 return 1; 506 } 507 508 /** 509 * p9_pollwait - add poll task to the wait queue 510 * @filp: file pointer being polled 511 * @wait_address: wait_q to block on 512 * @p: poll state 513 * 514 * called by files poll operation to add v9fs-poll task to files wait queue 515 */ 516 517 static void 518 p9_pollwait(struct file *filp, wait_queue_head_t *wait_address, poll_table *p) 519 { 520 struct p9_conn *m = container_of(p, struct p9_conn, pt); 521 struct p9_poll_wait *pwait = NULL; 522 int i; 523 524 for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) { 525 if (m->poll_wait[i].wait_addr == NULL) { 526 pwait = &m->poll_wait[i]; 527 break; 528 } 529 } 530 531 if (!pwait) { 532 p9_debug(P9_DEBUG_ERROR, "not enough wait_address slots\n"); 533 return; 534 } 535 536 pwait->conn = m; 537 pwait->wait_addr = wait_address; 538 init_waitqueue_func_entry(&pwait->wait, p9_pollwake); 539 add_wait_queue(wait_address, &pwait->wait); 540 } 541 542 /** 543 * p9_conn_create - initialize the per-session mux data 544 * @client: client instance 545 * 546 * Note: Creates the polling task if this is the first session. 547 */ 548 549 static void p9_conn_create(struct p9_client *client) 550 { 551 __poll_t n; 552 struct p9_trans_fd *ts = client->trans; 553 struct p9_conn *m = &ts->conn; 554 555 p9_debug(P9_DEBUG_TRANS, "client %p msize %d\n", client, client->msize); 556 557 INIT_LIST_HEAD(&m->mux_list); 558 m->client = client; 559 560 spin_lock_init(&m->req_lock); 561 INIT_LIST_HEAD(&m->req_list); 562 INIT_LIST_HEAD(&m->unsent_req_list); 563 INIT_WORK(&m->rq, p9_read_work); 564 INIT_WORK(&m->wq, p9_write_work); 565 INIT_LIST_HEAD(&m->poll_pending_link); 566 init_poll_funcptr(&m->pt, p9_pollwait); 567 568 n = p9_fd_poll(client, &m->pt, NULL); 569 if (n & EPOLLIN) { 570 p9_debug(P9_DEBUG_TRANS, "mux %p can read\n", m); 571 set_bit(Rpending, &m->wsched); 572 } 573 574 if (n & EPOLLOUT) { 575 p9_debug(P9_DEBUG_TRANS, "mux %p can write\n", m); 576 set_bit(Wpending, &m->wsched); 577 } 578 } 579 580 /** 581 * p9_poll_mux - polls a mux and schedules read or write works if necessary 582 * @m: connection to poll 583 * 584 */ 585 586 static void p9_poll_mux(struct p9_conn *m) 587 { 588 __poll_t n; 589 int err = -ECONNRESET; 590 591 if (READ_ONCE(m->err) < 0) 592 return; 593 594 n = p9_fd_poll(m->client, NULL, &err); 595 if (n & (EPOLLERR | EPOLLHUP | EPOLLNVAL)) { 596 p9_debug(P9_DEBUG_TRANS, "error mux %p err %d\n", m, n); 597 p9_conn_cancel(m, err); 598 } 599 600 if (n & EPOLLIN) { 601 set_bit(Rpending, &m->wsched); 602 p9_debug(P9_DEBUG_TRANS, "mux %p can read\n", m); 603 if (!test_and_set_bit(Rworksched, &m->wsched)) { 604 p9_debug(P9_DEBUG_TRANS, "sched read work %p\n", m); 605 schedule_work(&m->rq); 606 } 607 } 608 609 if (n & EPOLLOUT) { 610 set_bit(Wpending, &m->wsched); 611 p9_debug(P9_DEBUG_TRANS, "mux %p can write\n", m); 612 if ((m->wsize || !list_empty(&m->unsent_req_list)) && 613 !test_and_set_bit(Wworksched, &m->wsched)) { 614 p9_debug(P9_DEBUG_TRANS, "sched write work %p\n", m); 615 schedule_work(&m->wq); 616 } 617 } 618 } 619 620 /** 621 * p9_fd_request - send 9P request 622 * The function can sleep until the request is scheduled for sending. 623 * The function can be interrupted. Return from the function is not 624 * a guarantee that the request is sent successfully. 625 * 626 * @client: client instance 627 * @req: request to be sent 628 * 629 */ 630 631 static int p9_fd_request(struct p9_client *client, struct p9_req_t *req) 632 { 633 int err; 634 struct p9_trans_fd *ts = client->trans; 635 struct p9_conn *m = &ts->conn; 636 637 p9_debug(P9_DEBUG_TRANS, "mux %p task %p tcall %p id %d\n", 638 m, current, &req->tc, req->tc.id); 639 640 spin_lock(&m->req_lock); 641 642 err = READ_ONCE(m->err); 643 if (err < 0) { 644 spin_unlock(&m->req_lock); 645 return err; 646 } 647 648 WRITE_ONCE(req->status, REQ_STATUS_UNSENT); 649 list_add_tail(&req->req_list, &m->unsent_req_list); 650 spin_unlock(&m->req_lock); 651 652 p9_poll_mux(m); 653 654 return 0; 655 } 656 657 static int p9_fd_cancel(struct p9_client *client, struct p9_req_t *req) 658 { 659 struct p9_trans_fd *ts = client->trans; 660 struct p9_conn *m = &ts->conn; 661 int ret = 1; 662 663 p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req); 664 665 spin_lock(&m->req_lock); 666 667 if (req->status == REQ_STATUS_UNSENT) { 668 list_del(&req->req_list); 669 WRITE_ONCE(req->status, REQ_STATUS_FLSHD); 670 p9_req_put(client, req); 671 ret = 0; 672 } 673 spin_unlock(&m->req_lock); 674 675 return ret; 676 } 677 678 static int p9_fd_cancelled(struct p9_client *client, struct p9_req_t *req) 679 { 680 struct p9_trans_fd *ts = client->trans; 681 struct p9_conn *m = &ts->conn; 682 683 p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req); 684 685 spin_lock(&m->req_lock); 686 /* Ignore cancelled request if status changed since the request was 687 * processed in p9_client_flush() 688 */ 689 if (req->status != REQ_STATUS_SENT) { 690 spin_unlock(&m->req_lock); 691 return 0; 692 } 693 694 /* we haven't received a response for oldreq, 695 * remove it from the list. 696 */ 697 list_del(&req->req_list); 698 WRITE_ONCE(req->status, REQ_STATUS_FLSHD); 699 spin_unlock(&m->req_lock); 700 701 p9_req_put(client, req); 702 703 return 0; 704 } 705 706 static int p9_fd_show_options(struct seq_file *m, struct p9_client *clnt) 707 { 708 if (clnt->trans_mod == &p9_tcp_trans) { 709 if (clnt->trans_opts.tcp.port != P9_FD_PORT) 710 seq_printf(m, ",port=%u", clnt->trans_opts.tcp.port); 711 } else if (clnt->trans_mod == &p9_fd_trans) { 712 if (clnt->trans_opts.fd.rfd != ~0) 713 seq_printf(m, ",rfd=%u", clnt->trans_opts.fd.rfd); 714 if (clnt->trans_opts.fd.wfd != ~0) 715 seq_printf(m, ",wfd=%u", clnt->trans_opts.fd.wfd); 716 } 717 return 0; 718 } 719 720 static int p9_fd_open(struct p9_client *client, int rfd, int wfd) 721 { 722 struct p9_trans_fd *ts = kzalloc(sizeof(struct p9_trans_fd), 723 GFP_KERNEL); 724 if (!ts) 725 return -ENOMEM; 726 727 ts->rd = fget(rfd); 728 if (!ts->rd) 729 goto out_free_ts; 730 if (!(ts->rd->f_mode & FMODE_READ)) 731 goto out_put_rd; 732 /* Prevent workers from hanging on IO when fd is a pipe. 733 * It's technically possible for userspace or concurrent mounts to 734 * modify this flag concurrently, which will likely result in a 735 * broken filesystem. However, just having bad flags here should 736 * not crash the kernel or cause any other sort of bug, so mark this 737 * particular data race as intentional so that tooling (like KCSAN) 738 * can allow it and detect further problems. 739 */ 740 data_race(ts->rd->f_flags |= O_NONBLOCK); 741 ts->wr = fget(wfd); 742 if (!ts->wr) 743 goto out_put_rd; 744 if (!(ts->wr->f_mode & FMODE_WRITE)) 745 goto out_put_wr; 746 data_race(ts->wr->f_flags |= O_NONBLOCK); 747 748 client->trans = ts; 749 client->status = Connected; 750 751 return 0; 752 753 out_put_wr: 754 fput(ts->wr); 755 out_put_rd: 756 fput(ts->rd); 757 out_free_ts: 758 kfree(ts); 759 return -EIO; 760 } 761 762 static int p9_socket_open(struct p9_client *client, struct socket *csocket) 763 { 764 struct p9_trans_fd *p; 765 struct file *file; 766 767 p = kzalloc(sizeof(struct p9_trans_fd), GFP_KERNEL); 768 if (!p) { 769 sock_release(csocket); 770 return -ENOMEM; 771 } 772 773 csocket->sk->sk_allocation = GFP_NOIO; 774 csocket->sk->sk_use_task_frag = false; 775 file = sock_alloc_file(csocket, 0, NULL); 776 if (IS_ERR(file)) { 777 pr_err("%s (%d): failed to map fd\n", 778 __func__, task_pid_nr(current)); 779 kfree(p); 780 return PTR_ERR(file); 781 } 782 783 get_file(file); 784 p->wr = p->rd = file; 785 client->trans = p; 786 client->status = Connected; 787 788 p->rd->f_flags |= O_NONBLOCK; 789 790 p9_conn_create(client); 791 return 0; 792 } 793 794 /** 795 * p9_conn_destroy - cancels all pending requests of mux 796 * @m: mux to destroy 797 * 798 */ 799 800 static void p9_conn_destroy(struct p9_conn *m) 801 { 802 p9_debug(P9_DEBUG_TRANS, "mux %p prev %p next %p\n", 803 m, m->mux_list.prev, m->mux_list.next); 804 805 p9_mux_poll_stop(m); 806 cancel_work_sync(&m->rq); 807 if (m->rreq) { 808 p9_req_put(m->client, m->rreq); 809 m->rreq = NULL; 810 } 811 cancel_work_sync(&m->wq); 812 if (m->wreq) { 813 p9_req_put(m->client, m->wreq); 814 m->wreq = NULL; 815 } 816 817 p9_conn_cancel(m, -ECONNRESET); 818 819 m->client = NULL; 820 } 821 822 /** 823 * p9_fd_close - shutdown file descriptor transport 824 * @client: client instance 825 * 826 */ 827 828 static void p9_fd_close(struct p9_client *client) 829 { 830 struct p9_trans_fd *ts; 831 832 if (!client) 833 return; 834 835 ts = client->trans; 836 if (!ts) 837 return; 838 839 client->status = Disconnected; 840 841 p9_conn_destroy(&ts->conn); 842 843 if (ts->rd) 844 fput(ts->rd); 845 if (ts->wr) 846 fput(ts->wr); 847 848 kfree(ts); 849 } 850 851 static int p9_bind_privport(struct socket *sock) 852 { 853 struct sockaddr_storage stor = { 0 }; 854 int port, err = -EINVAL; 855 856 stor.ss_family = sock->ops->family; 857 if (stor.ss_family == AF_INET) 858 ((struct sockaddr_in *)&stor)->sin_addr.s_addr = htonl(INADDR_ANY); 859 else 860 ((struct sockaddr_in6 *)&stor)->sin6_addr = in6addr_any; 861 for (port = p9_ipport_resv_max; port >= p9_ipport_resv_min; port--) { 862 if (stor.ss_family == AF_INET) 863 ((struct sockaddr_in *)&stor)->sin_port = htons((ushort)port); 864 else 865 ((struct sockaddr_in6 *)&stor)->sin6_port = htons((ushort)port); 866 err = kernel_bind(sock, (struct sockaddr_unsized *)&stor, sizeof(stor)); 867 if (err != -EADDRINUSE) 868 break; 869 } 870 return err; 871 } 872 873 static int 874 p9_fd_create_tcp(struct p9_client *client, struct fs_context *fc) 875 { 876 const char *addr = fc->source; 877 struct v9fs_context *ctx = fc->fs_private; 878 int err; 879 char port_str[6]; 880 struct socket *csocket; 881 struct sockaddr_storage stor = { 0 }; 882 struct p9_fd_opts opts; 883 884 /* opts are already parsed in context */ 885 opts = ctx->fd_opts; 886 887 if (!addr) 888 return -EINVAL; 889 890 sprintf(port_str, "%u", opts.port); 891 err = inet_pton_with_scope(current->nsproxy->net_ns, AF_UNSPEC, addr, 892 port_str, &stor); 893 if (err < 0) 894 return err; 895 896 csocket = NULL; 897 898 client->trans_opts.tcp.port = opts.port; 899 client->trans_opts.tcp.privport = opts.privport; 900 err = __sock_create(current->nsproxy->net_ns, stor.ss_family, 901 SOCK_STREAM, IPPROTO_TCP, &csocket, 1); 902 if (err) { 903 pr_err("%s (%d): problem creating socket\n", 904 __func__, task_pid_nr(current)); 905 return err; 906 } 907 908 if (opts.privport) { 909 err = p9_bind_privport(csocket); 910 if (err < 0) { 911 pr_err("%s (%d): problem binding to privport\n", 912 __func__, task_pid_nr(current)); 913 sock_release(csocket); 914 return err; 915 } 916 } 917 918 err = READ_ONCE(csocket->ops)->connect(csocket, 919 (struct sockaddr_unsized *)&stor, 920 sizeof(stor), 0); 921 if (err < 0) { 922 pr_err("%s (%d): problem connecting socket to %s\n", 923 __func__, task_pid_nr(current), addr); 924 sock_release(csocket); 925 return err; 926 } 927 928 return p9_socket_open(client, csocket); 929 } 930 931 static int 932 p9_fd_create_unix(struct p9_client *client, struct fs_context *fc) 933 { 934 const char *addr = fc->source; 935 int err; 936 struct socket *csocket; 937 struct sockaddr_un sun_server; 938 939 csocket = NULL; 940 941 if (!addr || !strlen(addr)) 942 return -EINVAL; 943 944 if (strlen(addr) >= UNIX_PATH_MAX) { 945 pr_err("%s (%d): address too long: %s\n", 946 __func__, task_pid_nr(current), addr); 947 return -ENAMETOOLONG; 948 } 949 950 sun_server.sun_family = PF_UNIX; 951 strcpy(sun_server.sun_path, addr); 952 err = __sock_create(current->nsproxy->net_ns, PF_UNIX, 953 SOCK_STREAM, 0, &csocket, 1); 954 if (err < 0) { 955 pr_err("%s (%d): problem creating socket\n", 956 __func__, task_pid_nr(current)); 957 958 return err; 959 } 960 err = READ_ONCE(csocket->ops)->connect(csocket, (struct sockaddr_unsized *)&sun_server, 961 sizeof(struct sockaddr_un) - 1, 0); 962 if (err < 0) { 963 pr_err("%s (%d): problem connecting socket: %s: %d\n", 964 __func__, task_pid_nr(current), addr, err); 965 sock_release(csocket); 966 return err; 967 } 968 969 return p9_socket_open(client, csocket); 970 } 971 972 static int 973 p9_fd_create(struct p9_client *client, struct fs_context *fc) 974 { 975 struct v9fs_context *ctx = fc->fs_private; 976 struct p9_fd_opts opts = ctx->fd_opts; 977 int err; 978 979 client->trans_opts.fd.rfd = opts.rfd; 980 client->trans_opts.fd.wfd = opts.wfd; 981 982 if (opts.rfd == ~0 || opts.wfd == ~0) { 983 pr_err("Insufficient options for proto=fd\n"); 984 return -ENOPROTOOPT; 985 } 986 987 err = p9_fd_open(client, opts.rfd, opts.wfd); 988 if (err < 0) 989 return err; 990 991 p9_conn_create(client); 992 993 return 0; 994 } 995 996 static struct p9_trans_module p9_tcp_trans = { 997 .name = "tcp", 998 .maxsize = MAX_SOCK_BUF, 999 .pooled_rbuffers = false, 1000 .def = false, 1001 .supports_vmalloc = true, 1002 .create = p9_fd_create_tcp, 1003 .close = p9_fd_close, 1004 .request = p9_fd_request, 1005 .cancel = p9_fd_cancel, 1006 .cancelled = p9_fd_cancelled, 1007 .show_options = p9_fd_show_options, 1008 .owner = THIS_MODULE, 1009 }; 1010 MODULE_ALIAS_9P("tcp"); 1011 1012 static struct p9_trans_module p9_unix_trans = { 1013 .name = "unix", 1014 .maxsize = MAX_SOCK_BUF, 1015 .def = false, 1016 .supports_vmalloc = true, 1017 .create = p9_fd_create_unix, 1018 .close = p9_fd_close, 1019 .request = p9_fd_request, 1020 .cancel = p9_fd_cancel, 1021 .cancelled = p9_fd_cancelled, 1022 .show_options = p9_fd_show_options, 1023 .owner = THIS_MODULE, 1024 }; 1025 MODULE_ALIAS_9P("unix"); 1026 1027 static struct p9_trans_module p9_fd_trans = { 1028 .name = "fd", 1029 .maxsize = MAX_SOCK_BUF, 1030 .def = false, 1031 .supports_vmalloc = true, 1032 .create = p9_fd_create, 1033 .close = p9_fd_close, 1034 .request = p9_fd_request, 1035 .cancel = p9_fd_cancel, 1036 .cancelled = p9_fd_cancelled, 1037 .show_options = p9_fd_show_options, 1038 .owner = THIS_MODULE, 1039 }; 1040 MODULE_ALIAS_9P("fd"); 1041 1042 /** 1043 * p9_poll_workfn - poll worker thread 1044 * @work: work queue 1045 * 1046 * polls all v9fs transports for new events and queues the appropriate 1047 * work to the work queue 1048 * 1049 */ 1050 1051 static void p9_poll_workfn(struct work_struct *work) 1052 { 1053 unsigned long flags; 1054 1055 p9_debug(P9_DEBUG_TRANS, "start %p\n", current); 1056 1057 spin_lock_irqsave(&p9_poll_lock, flags); 1058 while (!list_empty(&p9_poll_pending_list)) { 1059 struct p9_conn *conn = list_first_entry(&p9_poll_pending_list, 1060 struct p9_conn, 1061 poll_pending_link); 1062 list_del_init(&conn->poll_pending_link); 1063 spin_unlock_irqrestore(&p9_poll_lock, flags); 1064 1065 p9_poll_mux(conn); 1066 1067 spin_lock_irqsave(&p9_poll_lock, flags); 1068 } 1069 spin_unlock_irqrestore(&p9_poll_lock, flags); 1070 1071 p9_debug(P9_DEBUG_TRANS, "finish\n"); 1072 } 1073 1074 static int __init p9_trans_fd_init(void) 1075 { 1076 v9fs_register_trans(&p9_tcp_trans); 1077 v9fs_register_trans(&p9_unix_trans); 1078 v9fs_register_trans(&p9_fd_trans); 1079 1080 return 0; 1081 } 1082 1083 static void __exit p9_trans_fd_exit(void) 1084 { 1085 flush_work(&p9_poll_work); 1086 v9fs_unregister_trans(&p9_tcp_trans); 1087 v9fs_unregister_trans(&p9_unix_trans); 1088 v9fs_unregister_trans(&p9_fd_trans); 1089 } 1090 1091 module_init(p9_trans_fd_init); 1092 module_exit(p9_trans_fd_exit); 1093 1094 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>"); 1095 MODULE_DESCRIPTION("Filedescriptor Transport for 9P"); 1096 MODULE_LICENSE("GPL"); 1097