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