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