1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) ST-Ericsson AB 2010 4 * Author: Sjur Brendeland 5 */ 6 7 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__ 8 9 #include <linux/filter.h> 10 #include <linux/fs.h> 11 #include <linux/init.h> 12 #include <linux/module.h> 13 #include <linux/sched/signal.h> 14 #include <linux/spinlock.h> 15 #include <linux/mutex.h> 16 #include <linux/list.h> 17 #include <linux/wait.h> 18 #include <linux/poll.h> 19 #include <linux/tcp.h> 20 #include <linux/uaccess.h> 21 #include <linux/debugfs.h> 22 #include <linux/caif/caif_socket.h> 23 #include <linux/pkt_sched.h> 24 #include <net/sock.h> 25 #include <net/tcp_states.h> 26 #include <net/caif/caif_layer.h> 27 #include <net/caif/caif_dev.h> 28 #include <net/caif/cfpkt.h> 29 30 MODULE_LICENSE("GPL"); 31 MODULE_ALIAS_NETPROTO(AF_CAIF); 32 33 /* 34 * CAIF state is re-using the TCP socket states. 35 * caif_states stored in sk_state reflect the state as reported by 36 * the CAIF stack, while sk_socket->state is the state of the socket. 37 */ 38 enum caif_states { 39 CAIF_CONNECTED = TCP_ESTABLISHED, 40 CAIF_CONNECTING = TCP_SYN_SENT, 41 CAIF_DISCONNECTED = TCP_CLOSE 42 }; 43 44 #define TX_FLOW_ON_BIT 1 45 #define RX_FLOW_ON_BIT 2 46 47 struct caifsock { 48 struct sock sk; /* must be first member */ 49 struct cflayer layer; 50 u32 flow_state; 51 struct caif_connect_request conn_req; 52 struct mutex readlock; 53 struct dentry *debugfs_socket_dir; 54 int headroom, tailroom, maxframe; 55 }; 56 57 static int rx_flow_is_on(struct caifsock *cf_sk) 58 { 59 return test_bit(RX_FLOW_ON_BIT, 60 (void *) &cf_sk->flow_state); 61 } 62 63 static int tx_flow_is_on(struct caifsock *cf_sk) 64 { 65 return test_bit(TX_FLOW_ON_BIT, 66 (void *) &cf_sk->flow_state); 67 } 68 69 static void set_rx_flow_off(struct caifsock *cf_sk) 70 { 71 clear_bit(RX_FLOW_ON_BIT, 72 (void *) &cf_sk->flow_state); 73 } 74 75 static void set_rx_flow_on(struct caifsock *cf_sk) 76 { 77 set_bit(RX_FLOW_ON_BIT, 78 (void *) &cf_sk->flow_state); 79 } 80 81 static void set_tx_flow_off(struct caifsock *cf_sk) 82 { 83 clear_bit(TX_FLOW_ON_BIT, 84 (void *) &cf_sk->flow_state); 85 } 86 87 static void set_tx_flow_on(struct caifsock *cf_sk) 88 { 89 set_bit(TX_FLOW_ON_BIT, 90 (void *) &cf_sk->flow_state); 91 } 92 93 static void caif_read_lock(struct sock *sk) 94 { 95 struct caifsock *cf_sk; 96 cf_sk = container_of(sk, struct caifsock, sk); 97 mutex_lock(&cf_sk->readlock); 98 } 99 100 static void caif_read_unlock(struct sock *sk) 101 { 102 struct caifsock *cf_sk; 103 cf_sk = container_of(sk, struct caifsock, sk); 104 mutex_unlock(&cf_sk->readlock); 105 } 106 107 static int sk_rcvbuf_lowwater(struct caifsock *cf_sk) 108 { 109 /* A quarter of full buffer is used a low water mark */ 110 return cf_sk->sk.sk_rcvbuf / 4; 111 } 112 113 static void caif_flow_ctrl(struct sock *sk, int mode) 114 { 115 struct caifsock *cf_sk; 116 cf_sk = container_of(sk, struct caifsock, sk); 117 if (cf_sk->layer.dn && cf_sk->layer.dn->modemcmd) 118 cf_sk->layer.dn->modemcmd(cf_sk->layer.dn, mode); 119 } 120 121 /* 122 * Copied from sock.c:sock_queue_rcv_skb(), but changed so packets are 123 * not dropped, but CAIF is sending flow off instead. 124 */ 125 static void caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) 126 { 127 int err; 128 unsigned long flags; 129 struct sk_buff_head *list = &sk->sk_receive_queue; 130 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 131 bool queued = false; 132 133 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >= 134 (unsigned int)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) { 135 net_dbg_ratelimited("sending flow OFF (queue len = %d %d)\n", 136 atomic_read(&cf_sk->sk.sk_rmem_alloc), 137 sk_rcvbuf_lowwater(cf_sk)); 138 set_rx_flow_off(cf_sk); 139 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ); 140 } 141 142 err = sk_filter(sk, skb); 143 if (err) 144 goto out; 145 146 if (!sk_rmem_schedule(sk, skb, skb->truesize) && rx_flow_is_on(cf_sk)) { 147 set_rx_flow_off(cf_sk); 148 net_dbg_ratelimited("sending flow OFF due to rmem_schedule\n"); 149 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ); 150 } 151 skb->dev = NULL; 152 skb_set_owner_r(skb, sk); 153 spin_lock_irqsave(&list->lock, flags); 154 queued = !sock_flag(sk, SOCK_DEAD); 155 if (queued) 156 __skb_queue_tail(list, skb); 157 spin_unlock_irqrestore(&list->lock, flags); 158 out: 159 if (queued) 160 sk->sk_data_ready(sk); 161 else 162 kfree_skb(skb); 163 } 164 165 /* Packet Receive Callback function called from CAIF Stack */ 166 static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt) 167 { 168 struct caifsock *cf_sk; 169 struct sk_buff *skb; 170 171 cf_sk = container_of(layr, struct caifsock, layer); 172 skb = cfpkt_tonative(pkt); 173 174 if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) { 175 kfree_skb(skb); 176 return 0; 177 } 178 caif_queue_rcv_skb(&cf_sk->sk, skb); 179 return 0; 180 } 181 182 static void cfsk_hold(struct cflayer *layr) 183 { 184 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer); 185 sock_hold(&cf_sk->sk); 186 } 187 188 static void cfsk_put(struct cflayer *layr) 189 { 190 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer); 191 sock_put(&cf_sk->sk); 192 } 193 194 /* Packet Control Callback function called from CAIF */ 195 static void caif_ctrl_cb(struct cflayer *layr, 196 enum caif_ctrlcmd flow, 197 int phyid) 198 { 199 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer); 200 switch (flow) { 201 case CAIF_CTRLCMD_FLOW_ON_IND: 202 /* OK from modem to start sending again */ 203 set_tx_flow_on(cf_sk); 204 cf_sk->sk.sk_state_change(&cf_sk->sk); 205 break; 206 207 case CAIF_CTRLCMD_FLOW_OFF_IND: 208 /* Modem asks us to shut up */ 209 set_tx_flow_off(cf_sk); 210 cf_sk->sk.sk_state_change(&cf_sk->sk); 211 break; 212 213 case CAIF_CTRLCMD_INIT_RSP: 214 /* We're now connected */ 215 caif_client_register_refcnt(&cf_sk->layer, 216 cfsk_hold, cfsk_put); 217 cf_sk->sk.sk_state = CAIF_CONNECTED; 218 set_tx_flow_on(cf_sk); 219 cf_sk->sk.sk_shutdown = 0; 220 cf_sk->sk.sk_state_change(&cf_sk->sk); 221 break; 222 223 case CAIF_CTRLCMD_DEINIT_RSP: 224 /* We're now disconnected */ 225 cf_sk->sk.sk_state = CAIF_DISCONNECTED; 226 cf_sk->sk.sk_state_change(&cf_sk->sk); 227 break; 228 229 case CAIF_CTRLCMD_INIT_FAIL_RSP: 230 /* Connect request failed */ 231 cf_sk->sk.sk_err = ECONNREFUSED; 232 cf_sk->sk.sk_state = CAIF_DISCONNECTED; 233 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK; 234 /* 235 * Socket "standards" seems to require POLLOUT to 236 * be set at connect failure. 237 */ 238 set_tx_flow_on(cf_sk); 239 cf_sk->sk.sk_state_change(&cf_sk->sk); 240 break; 241 242 case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND: 243 /* Modem has closed this connection, or device is down. */ 244 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK; 245 cf_sk->sk.sk_err = ECONNRESET; 246 set_rx_flow_on(cf_sk); 247 sk_error_report(&cf_sk->sk); 248 break; 249 250 default: 251 pr_debug("Unexpected flow command %d\n", flow); 252 } 253 } 254 255 static void caif_check_flow_release(struct sock *sk) 256 { 257 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 258 259 if (rx_flow_is_on(cf_sk)) 260 return; 261 262 if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) { 263 set_rx_flow_on(cf_sk); 264 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ); 265 } 266 } 267 268 /* 269 * Copied from unix_dgram_recvmsg, but removed credit checks, 270 * changed locking, address handling and added MSG_TRUNC. 271 */ 272 static int caif_seqpkt_recvmsg(struct socket *sock, struct msghdr *m, 273 size_t len, int flags) 274 275 { 276 struct sock *sk = sock->sk; 277 struct sk_buff *skb; 278 int ret; 279 int copylen; 280 281 ret = -EOPNOTSUPP; 282 if (flags & MSG_OOB) 283 goto read_error; 284 285 skb = skb_recv_datagram(sk, flags, 0 , &ret); 286 if (!skb) 287 goto read_error; 288 copylen = skb->len; 289 if (len < copylen) { 290 m->msg_flags |= MSG_TRUNC; 291 copylen = len; 292 } 293 294 ret = skb_copy_datagram_msg(skb, 0, m, copylen); 295 if (ret) 296 goto out_free; 297 298 ret = (flags & MSG_TRUNC) ? skb->len : copylen; 299 out_free: 300 skb_free_datagram(sk, skb); 301 caif_check_flow_release(sk); 302 return ret; 303 304 read_error: 305 return ret; 306 } 307 308 309 /* Copied from unix_stream_wait_data, identical except for lock call. */ 310 static long caif_stream_data_wait(struct sock *sk, long timeo) 311 { 312 DEFINE_WAIT(wait); 313 lock_sock(sk); 314 315 for (;;) { 316 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); 317 318 if (!skb_queue_empty(&sk->sk_receive_queue) || 319 sk->sk_err || 320 sk->sk_state != CAIF_CONNECTED || 321 sock_flag(sk, SOCK_DEAD) || 322 (sk->sk_shutdown & RCV_SHUTDOWN) || 323 signal_pending(current) || 324 !timeo) 325 break; 326 327 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); 328 release_sock(sk); 329 timeo = schedule_timeout(timeo); 330 lock_sock(sk); 331 332 if (sock_flag(sk, SOCK_DEAD)) 333 break; 334 335 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); 336 } 337 338 finish_wait(sk_sleep(sk), &wait); 339 release_sock(sk); 340 return timeo; 341 } 342 343 344 /* 345 * Copied from unix_stream_recvmsg, but removed credit checks, 346 * changed locking calls, changed address handling. 347 */ 348 static int caif_stream_recvmsg(struct socket *sock, struct msghdr *msg, 349 size_t size, int flags) 350 { 351 struct sock *sk = sock->sk; 352 int copied = 0; 353 int target; 354 int err = 0; 355 long timeo; 356 357 err = -EOPNOTSUPP; 358 if (flags&MSG_OOB) 359 goto out; 360 361 /* 362 * Lock the socket to prevent queue disordering 363 * while sleeps in memcpy_tomsg 364 */ 365 err = -EAGAIN; 366 if (sk->sk_state == CAIF_CONNECTING) 367 goto out; 368 369 caif_read_lock(sk); 370 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size); 371 timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT); 372 373 do { 374 int chunk; 375 struct sk_buff *skb; 376 377 lock_sock(sk); 378 if (sock_flag(sk, SOCK_DEAD)) { 379 err = -ECONNRESET; 380 goto unlock; 381 } 382 skb = skb_dequeue(&sk->sk_receive_queue); 383 caif_check_flow_release(sk); 384 385 if (skb == NULL) { 386 if (copied >= target) 387 goto unlock; 388 /* 389 * POSIX 1003.1g mandates this order. 390 */ 391 err = sock_error(sk); 392 if (err) 393 goto unlock; 394 err = -ECONNRESET; 395 if (sk->sk_shutdown & RCV_SHUTDOWN) 396 goto unlock; 397 398 err = -EPIPE; 399 if (sk->sk_state != CAIF_CONNECTED) 400 goto unlock; 401 if (sock_flag(sk, SOCK_DEAD)) 402 goto unlock; 403 404 release_sock(sk); 405 406 err = -EAGAIN; 407 if (!timeo) 408 break; 409 410 caif_read_unlock(sk); 411 412 timeo = caif_stream_data_wait(sk, timeo); 413 414 if (signal_pending(current)) { 415 err = sock_intr_errno(timeo); 416 goto out; 417 } 418 caif_read_lock(sk); 419 continue; 420 unlock: 421 release_sock(sk); 422 break; 423 } 424 release_sock(sk); 425 chunk = min_t(unsigned int, skb->len, size); 426 if (memcpy_to_msg(msg, skb->data, chunk)) { 427 skb_queue_head(&sk->sk_receive_queue, skb); 428 if (copied == 0) 429 copied = -EFAULT; 430 break; 431 } 432 copied += chunk; 433 size -= chunk; 434 435 /* Mark read part of skb as used */ 436 if (!(flags & MSG_PEEK)) { 437 skb_pull(skb, chunk); 438 439 /* put the skb back if we didn't use it up. */ 440 if (skb->len) { 441 skb_queue_head(&sk->sk_receive_queue, skb); 442 break; 443 } 444 kfree_skb(skb); 445 446 } else { 447 /* 448 * It is questionable, see note in unix_dgram_recvmsg. 449 */ 450 /* put message back and return */ 451 skb_queue_head(&sk->sk_receive_queue, skb); 452 break; 453 } 454 } while (size); 455 caif_read_unlock(sk); 456 457 out: 458 return copied ? : err; 459 } 460 461 /* 462 * Copied from sock.c:sock_wait_for_wmem, but change to wait for 463 * CAIF flow-on and sock_writable. 464 */ 465 static long caif_wait_for_flow_on(struct caifsock *cf_sk, 466 int wait_writeable, long timeo, int *err) 467 { 468 struct sock *sk = &cf_sk->sk; 469 DEFINE_WAIT(wait); 470 for (;;) { 471 *err = 0; 472 if (tx_flow_is_on(cf_sk) && 473 (!wait_writeable || sock_writeable(&cf_sk->sk))) 474 break; 475 *err = -ETIMEDOUT; 476 if (!timeo) 477 break; 478 *err = -ERESTARTSYS; 479 if (signal_pending(current)) 480 break; 481 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); 482 *err = -ECONNRESET; 483 if (sk->sk_shutdown & SHUTDOWN_MASK) 484 break; 485 *err = -sk->sk_err; 486 if (sk->sk_err) 487 break; 488 *err = -EPIPE; 489 if (cf_sk->sk.sk_state != CAIF_CONNECTED) 490 break; 491 timeo = schedule_timeout(timeo); 492 } 493 finish_wait(sk_sleep(sk), &wait); 494 return timeo; 495 } 496 497 /* 498 * Transmit a SKB. The device may temporarily request re-transmission 499 * by returning EAGAIN. 500 */ 501 static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk, 502 int noblock, long timeo) 503 { 504 struct cfpkt *pkt; 505 506 pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb); 507 memset(skb->cb, 0, sizeof(struct caif_payload_info)); 508 cfpkt_set_prio(pkt, cf_sk->sk.sk_priority); 509 510 if (cf_sk->layer.dn == NULL) { 511 kfree_skb(skb); 512 return -EINVAL; 513 } 514 515 return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt); 516 } 517 518 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */ 519 static int caif_seqpkt_sendmsg(struct socket *sock, struct msghdr *msg, 520 size_t len) 521 { 522 struct sock *sk = sock->sk; 523 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 524 int buffer_size; 525 int ret = 0; 526 struct sk_buff *skb = NULL; 527 int noblock; 528 long timeo; 529 caif_assert(cf_sk); 530 ret = sock_error(sk); 531 if (ret) 532 goto err; 533 534 ret = -EOPNOTSUPP; 535 if (msg->msg_flags&MSG_OOB) 536 goto err; 537 538 ret = -EOPNOTSUPP; 539 if (msg->msg_namelen) 540 goto err; 541 542 ret = -EINVAL; 543 if (unlikely(msg->msg_iter.nr_segs == 0) || 544 unlikely(msg->msg_iter.iov->iov_base == NULL)) 545 goto err; 546 noblock = msg->msg_flags & MSG_DONTWAIT; 547 548 timeo = sock_sndtimeo(sk, noblock); 549 timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk), 550 1, timeo, &ret); 551 552 if (ret) 553 goto err; 554 ret = -EPIPE; 555 if (cf_sk->sk.sk_state != CAIF_CONNECTED || 556 sock_flag(sk, SOCK_DEAD) || 557 (sk->sk_shutdown & RCV_SHUTDOWN)) 558 goto err; 559 560 /* Error if trying to write more than maximum frame size. */ 561 ret = -EMSGSIZE; 562 if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM) 563 goto err; 564 565 buffer_size = len + cf_sk->headroom + cf_sk->tailroom; 566 567 ret = -ENOMEM; 568 skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret); 569 570 if (!skb || skb_tailroom(skb) < buffer_size) 571 goto err; 572 573 skb_reserve(skb, cf_sk->headroom); 574 575 ret = memcpy_from_msg(skb_put(skb, len), msg, len); 576 577 if (ret) 578 goto err; 579 ret = transmit_skb(skb, cf_sk, noblock, timeo); 580 if (ret < 0) 581 /* skb is already freed */ 582 return ret; 583 584 return len; 585 err: 586 kfree_skb(skb); 587 return ret; 588 } 589 590 /* 591 * Copied from unix_stream_sendmsg and adapted to CAIF: 592 * Changed removed permission handling and added waiting for flow on 593 * and other minor adaptations. 594 */ 595 static int caif_stream_sendmsg(struct socket *sock, struct msghdr *msg, 596 size_t len) 597 { 598 struct sock *sk = sock->sk; 599 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 600 int err, size; 601 struct sk_buff *skb; 602 int sent = 0; 603 long timeo; 604 605 err = -EOPNOTSUPP; 606 if (unlikely(msg->msg_flags&MSG_OOB)) 607 goto out_err; 608 609 if (unlikely(msg->msg_namelen)) 610 goto out_err; 611 612 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 613 timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err); 614 615 if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN)) 616 goto pipe_err; 617 618 while (sent < len) { 619 620 size = len-sent; 621 622 if (size > cf_sk->maxframe) 623 size = cf_sk->maxframe; 624 625 /* If size is more than half of sndbuf, chop up message */ 626 if (size > ((sk->sk_sndbuf >> 1) - 64)) 627 size = (sk->sk_sndbuf >> 1) - 64; 628 629 if (size > SKB_MAX_ALLOC) 630 size = SKB_MAX_ALLOC; 631 632 skb = sock_alloc_send_skb(sk, 633 size + cf_sk->headroom + 634 cf_sk->tailroom, 635 msg->msg_flags&MSG_DONTWAIT, 636 &err); 637 if (skb == NULL) 638 goto out_err; 639 640 skb_reserve(skb, cf_sk->headroom); 641 /* 642 * If you pass two values to the sock_alloc_send_skb 643 * it tries to grab the large buffer with GFP_NOFS 644 * (which can fail easily), and if it fails grab the 645 * fallback size buffer which is under a page and will 646 * succeed. [Alan] 647 */ 648 size = min_t(int, size, skb_tailroom(skb)); 649 650 err = memcpy_from_msg(skb_put(skb, size), msg, size); 651 if (err) { 652 kfree_skb(skb); 653 goto out_err; 654 } 655 err = transmit_skb(skb, cf_sk, 656 msg->msg_flags&MSG_DONTWAIT, timeo); 657 if (err < 0) 658 /* skb is already freed */ 659 goto pipe_err; 660 661 sent += size; 662 } 663 664 return sent; 665 666 pipe_err: 667 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL)) 668 send_sig(SIGPIPE, current, 0); 669 err = -EPIPE; 670 out_err: 671 return sent ? : err; 672 } 673 674 static int setsockopt(struct socket *sock, int lvl, int opt, sockptr_t ov, 675 unsigned int ol) 676 { 677 struct sock *sk = sock->sk; 678 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 679 int linksel; 680 681 if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED) 682 return -ENOPROTOOPT; 683 684 switch (opt) { 685 case CAIFSO_LINK_SELECT: 686 if (ol < sizeof(int)) 687 return -EINVAL; 688 if (lvl != SOL_CAIF) 689 goto bad_sol; 690 if (copy_from_sockptr(&linksel, ov, sizeof(int))) 691 return -EINVAL; 692 lock_sock(&(cf_sk->sk)); 693 cf_sk->conn_req.link_selector = linksel; 694 release_sock(&cf_sk->sk); 695 return 0; 696 697 case CAIFSO_REQ_PARAM: 698 if (lvl != SOL_CAIF) 699 goto bad_sol; 700 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL) 701 return -ENOPROTOOPT; 702 lock_sock(&(cf_sk->sk)); 703 if (ol > sizeof(cf_sk->conn_req.param.data) || 704 copy_from_sockptr(&cf_sk->conn_req.param.data, ov, ol)) { 705 release_sock(&cf_sk->sk); 706 return -EINVAL; 707 } 708 cf_sk->conn_req.param.size = ol; 709 release_sock(&cf_sk->sk); 710 return 0; 711 712 default: 713 return -ENOPROTOOPT; 714 } 715 716 return 0; 717 bad_sol: 718 return -ENOPROTOOPT; 719 720 } 721 722 /* 723 * caif_connect() - Connect a CAIF Socket 724 * Copied and modified af_irda.c:irda_connect(). 725 * 726 * Note : by consulting "errno", the user space caller may learn the cause 727 * of the failure. Most of them are visible in the function, others may come 728 * from subroutines called and are listed here : 729 * o -EAFNOSUPPORT: bad socket family or type. 730 * o -ESOCKTNOSUPPORT: bad socket type or protocol 731 * o -EINVAL: bad socket address, or CAIF link type 732 * o -ECONNREFUSED: remote end refused the connection. 733 * o -EINPROGRESS: connect request sent but timed out (or non-blocking) 734 * o -EISCONN: already connected. 735 * o -ETIMEDOUT: Connection timed out (send timeout) 736 * o -ENODEV: No link layer to send request 737 * o -ECONNRESET: Received Shutdown indication or lost link layer 738 * o -ENOMEM: Out of memory 739 * 740 * State Strategy: 741 * o sk_state: holds the CAIF_* protocol state, it's updated by 742 * caif_ctrl_cb. 743 * o sock->state: holds the SS_* socket state and is updated by connect and 744 * disconnect. 745 */ 746 static int caif_connect(struct socket *sock, struct sockaddr *uaddr, 747 int addr_len, int flags) 748 { 749 struct sock *sk = sock->sk; 750 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 751 long timeo; 752 int err; 753 int ifindex, headroom, tailroom; 754 unsigned int mtu; 755 struct net_device *dev; 756 757 lock_sock(sk); 758 759 err = -EINVAL; 760 if (addr_len < offsetofend(struct sockaddr, sa_family)) 761 goto out; 762 763 err = -EAFNOSUPPORT; 764 if (uaddr->sa_family != AF_CAIF) 765 goto out; 766 767 switch (sock->state) { 768 case SS_UNCONNECTED: 769 /* Normal case, a fresh connect */ 770 caif_assert(sk->sk_state == CAIF_DISCONNECTED); 771 break; 772 case SS_CONNECTING: 773 switch (sk->sk_state) { 774 case CAIF_CONNECTED: 775 sock->state = SS_CONNECTED; 776 err = -EISCONN; 777 goto out; 778 case CAIF_DISCONNECTED: 779 /* Reconnect allowed */ 780 break; 781 case CAIF_CONNECTING: 782 err = -EALREADY; 783 if (flags & O_NONBLOCK) 784 goto out; 785 goto wait_connect; 786 } 787 break; 788 case SS_CONNECTED: 789 caif_assert(sk->sk_state == CAIF_CONNECTED || 790 sk->sk_state == CAIF_DISCONNECTED); 791 if (sk->sk_shutdown & SHUTDOWN_MASK) { 792 /* Allow re-connect after SHUTDOWN_IND */ 793 caif_disconnect_client(sock_net(sk), &cf_sk->layer); 794 caif_free_client(&cf_sk->layer); 795 break; 796 } 797 /* No reconnect on a seqpacket socket */ 798 err = -EISCONN; 799 goto out; 800 case SS_DISCONNECTING: 801 case SS_FREE: 802 caif_assert(1); /*Should never happen */ 803 break; 804 } 805 sk->sk_state = CAIF_DISCONNECTED; 806 sock->state = SS_UNCONNECTED; 807 sk_stream_kill_queues(&cf_sk->sk); 808 809 err = -EINVAL; 810 if (addr_len != sizeof(struct sockaddr_caif)) 811 goto out; 812 813 memcpy(&cf_sk->conn_req.sockaddr, uaddr, 814 sizeof(struct sockaddr_caif)); 815 816 /* Move to connecting socket, start sending Connect Requests */ 817 sock->state = SS_CONNECTING; 818 sk->sk_state = CAIF_CONNECTING; 819 820 /* Check priority value comming from socket */ 821 /* if priority value is out of range it will be ajusted */ 822 if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX) 823 cf_sk->conn_req.priority = CAIF_PRIO_MAX; 824 else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN) 825 cf_sk->conn_req.priority = CAIF_PRIO_MIN; 826 else 827 cf_sk->conn_req.priority = cf_sk->sk.sk_priority; 828 829 /*ifindex = id of the interface.*/ 830 cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if; 831 832 cf_sk->layer.receive = caif_sktrecv_cb; 833 834 err = caif_connect_client(sock_net(sk), &cf_sk->conn_req, 835 &cf_sk->layer, &ifindex, &headroom, &tailroom); 836 837 if (err < 0) { 838 cf_sk->sk.sk_socket->state = SS_UNCONNECTED; 839 cf_sk->sk.sk_state = CAIF_DISCONNECTED; 840 goto out; 841 } 842 843 err = -ENODEV; 844 rcu_read_lock(); 845 dev = dev_get_by_index_rcu(sock_net(sk), ifindex); 846 if (!dev) { 847 rcu_read_unlock(); 848 goto out; 849 } 850 cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom); 851 mtu = dev->mtu; 852 rcu_read_unlock(); 853 854 cf_sk->tailroom = tailroom; 855 cf_sk->maxframe = mtu - (headroom + tailroom); 856 if (cf_sk->maxframe < 1) { 857 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu); 858 err = -ENODEV; 859 goto out; 860 } 861 862 err = -EINPROGRESS; 863 wait_connect: 864 865 if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK)) 866 goto out; 867 868 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK); 869 870 release_sock(sk); 871 err = -ERESTARTSYS; 872 timeo = wait_event_interruptible_timeout(*sk_sleep(sk), 873 sk->sk_state != CAIF_CONNECTING, 874 timeo); 875 lock_sock(sk); 876 if (timeo < 0) 877 goto out; /* -ERESTARTSYS */ 878 879 err = -ETIMEDOUT; 880 if (timeo == 0 && sk->sk_state != CAIF_CONNECTED) 881 goto out; 882 if (sk->sk_state != CAIF_CONNECTED) { 883 sock->state = SS_UNCONNECTED; 884 err = sock_error(sk); 885 if (!err) 886 err = -ECONNREFUSED; 887 goto out; 888 } 889 sock->state = SS_CONNECTED; 890 err = 0; 891 out: 892 release_sock(sk); 893 return err; 894 } 895 896 /* 897 * caif_release() - Disconnect a CAIF Socket 898 * Copied and modified af_irda.c:irda_release(). 899 */ 900 static int caif_release(struct socket *sock) 901 { 902 struct sock *sk = sock->sk; 903 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 904 905 if (!sk) 906 return 0; 907 908 set_tx_flow_off(cf_sk); 909 910 /* 911 * Ensure that packets are not queued after this point in time. 912 * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock, 913 * this ensures no packets when sock is dead. 914 */ 915 spin_lock_bh(&sk->sk_receive_queue.lock); 916 sock_set_flag(sk, SOCK_DEAD); 917 spin_unlock_bh(&sk->sk_receive_queue.lock); 918 sock->sk = NULL; 919 920 WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir)); 921 debugfs_remove_recursive(cf_sk->debugfs_socket_dir); 922 923 lock_sock(&(cf_sk->sk)); 924 sk->sk_state = CAIF_DISCONNECTED; 925 sk->sk_shutdown = SHUTDOWN_MASK; 926 927 caif_disconnect_client(sock_net(sk), &cf_sk->layer); 928 cf_sk->sk.sk_socket->state = SS_DISCONNECTING; 929 wake_up_interruptible_poll(sk_sleep(sk), EPOLLERR|EPOLLHUP); 930 931 sock_orphan(sk); 932 sk_stream_kill_queues(&cf_sk->sk); 933 release_sock(sk); 934 sock_put(sk); 935 return 0; 936 } 937 938 /* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */ 939 static __poll_t caif_poll(struct file *file, 940 struct socket *sock, poll_table *wait) 941 { 942 struct sock *sk = sock->sk; 943 __poll_t mask; 944 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 945 946 sock_poll_wait(file, sock, wait); 947 mask = 0; 948 949 /* exceptional events? */ 950 if (sk->sk_err) 951 mask |= EPOLLERR; 952 if (sk->sk_shutdown == SHUTDOWN_MASK) 953 mask |= EPOLLHUP; 954 if (sk->sk_shutdown & RCV_SHUTDOWN) 955 mask |= EPOLLRDHUP; 956 957 /* readable? */ 958 if (!skb_queue_empty_lockless(&sk->sk_receive_queue) || 959 (sk->sk_shutdown & RCV_SHUTDOWN)) 960 mask |= EPOLLIN | EPOLLRDNORM; 961 962 /* 963 * we set writable also when the other side has shut down the 964 * connection. This prevents stuck sockets. 965 */ 966 if (sock_writeable(sk) && tx_flow_is_on(cf_sk)) 967 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND; 968 969 return mask; 970 } 971 972 static const struct proto_ops caif_seqpacket_ops = { 973 .family = PF_CAIF, 974 .owner = THIS_MODULE, 975 .release = caif_release, 976 .bind = sock_no_bind, 977 .connect = caif_connect, 978 .socketpair = sock_no_socketpair, 979 .accept = sock_no_accept, 980 .getname = sock_no_getname, 981 .poll = caif_poll, 982 .ioctl = sock_no_ioctl, 983 .listen = sock_no_listen, 984 .shutdown = sock_no_shutdown, 985 .setsockopt = setsockopt, 986 .sendmsg = caif_seqpkt_sendmsg, 987 .recvmsg = caif_seqpkt_recvmsg, 988 .mmap = sock_no_mmap, 989 .sendpage = sock_no_sendpage, 990 }; 991 992 static const struct proto_ops caif_stream_ops = { 993 .family = PF_CAIF, 994 .owner = THIS_MODULE, 995 .release = caif_release, 996 .bind = sock_no_bind, 997 .connect = caif_connect, 998 .socketpair = sock_no_socketpair, 999 .accept = sock_no_accept, 1000 .getname = sock_no_getname, 1001 .poll = caif_poll, 1002 .ioctl = sock_no_ioctl, 1003 .listen = sock_no_listen, 1004 .shutdown = sock_no_shutdown, 1005 .setsockopt = setsockopt, 1006 .sendmsg = caif_stream_sendmsg, 1007 .recvmsg = caif_stream_recvmsg, 1008 .mmap = sock_no_mmap, 1009 .sendpage = sock_no_sendpage, 1010 }; 1011 1012 /* This function is called when a socket is finally destroyed. */ 1013 static void caif_sock_destructor(struct sock *sk) 1014 { 1015 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 1016 caif_assert(!refcount_read(&sk->sk_wmem_alloc)); 1017 caif_assert(sk_unhashed(sk)); 1018 caif_assert(!sk->sk_socket); 1019 if (!sock_flag(sk, SOCK_DEAD)) { 1020 pr_debug("Attempt to release alive CAIF socket: %p\n", sk); 1021 return; 1022 } 1023 sk_stream_kill_queues(&cf_sk->sk); 1024 caif_free_client(&cf_sk->layer); 1025 } 1026 1027 static int caif_create(struct net *net, struct socket *sock, int protocol, 1028 int kern) 1029 { 1030 struct sock *sk = NULL; 1031 struct caifsock *cf_sk = NULL; 1032 static struct proto prot = {.name = "PF_CAIF", 1033 .owner = THIS_MODULE, 1034 .obj_size = sizeof(struct caifsock), 1035 .useroffset = offsetof(struct caifsock, conn_req.param), 1036 .usersize = sizeof_field(struct caifsock, conn_req.param) 1037 }; 1038 1039 if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN)) 1040 return -EPERM; 1041 /* 1042 * The sock->type specifies the socket type to use. 1043 * The CAIF socket is a packet stream in the sense 1044 * that it is packet based. CAIF trusts the reliability 1045 * of the link, no resending is implemented. 1046 */ 1047 if (sock->type == SOCK_SEQPACKET) 1048 sock->ops = &caif_seqpacket_ops; 1049 else if (sock->type == SOCK_STREAM) 1050 sock->ops = &caif_stream_ops; 1051 else 1052 return -ESOCKTNOSUPPORT; 1053 1054 if (protocol < 0 || protocol >= CAIFPROTO_MAX) 1055 return -EPROTONOSUPPORT; 1056 /* 1057 * Set the socket state to unconnected. The socket state 1058 * is really not used at all in the net/core or socket.c but the 1059 * initialization makes sure that sock->state is not uninitialized. 1060 */ 1061 sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot, kern); 1062 if (!sk) 1063 return -ENOMEM; 1064 1065 cf_sk = container_of(sk, struct caifsock, sk); 1066 1067 /* Store the protocol */ 1068 sk->sk_protocol = (unsigned char) protocol; 1069 1070 /* Initialize default priority for well-known cases */ 1071 switch (protocol) { 1072 case CAIFPROTO_AT: 1073 sk->sk_priority = TC_PRIO_CONTROL; 1074 break; 1075 case CAIFPROTO_RFM: 1076 sk->sk_priority = TC_PRIO_INTERACTIVE_BULK; 1077 break; 1078 default: 1079 sk->sk_priority = TC_PRIO_BESTEFFORT; 1080 } 1081 1082 /* 1083 * Lock in order to try to stop someone from opening the socket 1084 * too early. 1085 */ 1086 lock_sock(&(cf_sk->sk)); 1087 1088 /* Initialize the nozero default sock structure data. */ 1089 sock_init_data(sock, sk); 1090 sk->sk_destruct = caif_sock_destructor; 1091 1092 mutex_init(&cf_sk->readlock); /* single task reading lock */ 1093 cf_sk->layer.ctrlcmd = caif_ctrl_cb; 1094 cf_sk->sk.sk_socket->state = SS_UNCONNECTED; 1095 cf_sk->sk.sk_state = CAIF_DISCONNECTED; 1096 1097 set_tx_flow_off(cf_sk); 1098 set_rx_flow_on(cf_sk); 1099 1100 /* Set default options on configuration */ 1101 cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY; 1102 cf_sk->conn_req.protocol = protocol; 1103 release_sock(&cf_sk->sk); 1104 return 0; 1105 } 1106 1107 1108 static const struct net_proto_family caif_family_ops = { 1109 .family = PF_CAIF, 1110 .create = caif_create, 1111 .owner = THIS_MODULE, 1112 }; 1113 1114 static int __init caif_sktinit_module(void) 1115 { 1116 return sock_register(&caif_family_ops); 1117 } 1118 1119 static void __exit caif_sktexit_module(void) 1120 { 1121 sock_unregister(PF_CAIF); 1122 } 1123 module_init(caif_sktinit_module); 1124 module_exit(caif_sktexit_module); 1125