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 29MODULE_LICENSE("GPL"); 30MODULE_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 */ 37enum 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 46struct 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 56static 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 62static 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 68static 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 74static 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 80static 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 86static 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 92static 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 99static 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 106static 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 112static 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 */ 124static 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); 157out: 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 */ 165static 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 181static 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 187static 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 */ 194static 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 254static 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 */ 271static 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; 298out_free: 299 skb_free_datagram(sk, skb); 300 caif_check_flow_release(sk); 301 return ret; 302 303read_error: 304 return ret; 305} 306 307 308/* Copied from unix_stream_wait_data, identical except for lock call. */ 309static 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 */ 347static 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; 419unlock: 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 456out: 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 */ 464static 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 */ 500static 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 */ 518static 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.nr_segs == 0) || 543 unlikely(msg->msg_iter.iov->iov_base == NULL)) 544 goto err; 545 noblock = msg->msg_flags & MSG_DONTWAIT; 546 547 timeo = sock_sndtimeo(sk, noblock); 548 timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk), 549 1, timeo, &ret); 550 551 if (ret) 552 goto err; 553 ret = -EPIPE; 554 if (cf_sk->sk.sk_state != CAIF_CONNECTED || 555 sock_flag(sk, SOCK_DEAD) || 556 (sk->sk_shutdown & RCV_SHUTDOWN)) 557 goto err; 558 559 /* Error if trying to write more than maximum frame size. */ 560 ret = -EMSGSIZE; 561 if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM) 562 goto err; 563 564 buffer_size = len + cf_sk->headroom + cf_sk->tailroom; 565 566 ret = -ENOMEM; 567 skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret); 568 569 if (!skb || skb_tailroom(skb) < buffer_size) 570 goto err; 571 572 skb_reserve(skb, cf_sk->headroom); 573 574 ret = memcpy_from_msg(skb_put(skb, len), msg, len); 575 576 if (ret) 577 goto err; 578 ret = transmit_skb(skb, cf_sk, noblock, timeo); 579 if (ret < 0) 580 /* skb is already freed */ 581 return ret; 582 583 return len; 584err: 585 kfree_skb(skb); 586 return ret; 587} 588 589/* 590 * Copied from unix_stream_sendmsg and adapted to CAIF: 591 * Changed removed permission handling and added waiting for flow on 592 * and other minor adaptations. 593 */ 594static int caif_stream_sendmsg(struct socket *sock, struct msghdr *msg, 595 size_t len) 596{ 597 struct sock *sk = sock->sk; 598 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 599 int err, size; 600 struct sk_buff *skb; 601 int sent = 0; 602 long timeo; 603 604 err = -EOPNOTSUPP; 605 if (unlikely(msg->msg_flags&MSG_OOB)) 606 goto out_err; 607 608 if (unlikely(msg->msg_namelen)) 609 goto out_err; 610 611 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 612 timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err); 613 614 if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN)) 615 goto pipe_err; 616 617 while (sent < len) { 618 619 size = len-sent; 620 621 if (size > cf_sk->maxframe) 622 size = cf_sk->maxframe; 623 624 /* If size is more than half of sndbuf, chop up message */ 625 if (size > ((sk->sk_sndbuf >> 1) - 64)) 626 size = (sk->sk_sndbuf >> 1) - 64; 627 628 if (size > SKB_MAX_ALLOC) 629 size = SKB_MAX_ALLOC; 630 631 skb = sock_alloc_send_skb(sk, 632 size + cf_sk->headroom + 633 cf_sk->tailroom, 634 msg->msg_flags&MSG_DONTWAIT, 635 &err); 636 if (skb == NULL) 637 goto out_err; 638 639 skb_reserve(skb, cf_sk->headroom); 640 /* 641 * If you pass two values to the sock_alloc_send_skb 642 * it tries to grab the large buffer with GFP_NOFS 643 * (which can fail easily), and if it fails grab the 644 * fallback size buffer which is under a page and will 645 * succeed. [Alan] 646 */ 647 size = min_t(int, size, skb_tailroom(skb)); 648 649 err = memcpy_from_msg(skb_put(skb, size), msg, size); 650 if (err) { 651 kfree_skb(skb); 652 goto out_err; 653 } 654 err = transmit_skb(skb, cf_sk, 655 msg->msg_flags&MSG_DONTWAIT, timeo); 656 if (err < 0) 657 /* skb is already freed */ 658 goto pipe_err; 659 660 sent += size; 661 } 662 663 return sent; 664 665pipe_err: 666 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL)) 667 send_sig(SIGPIPE, current, 0); 668 err = -EPIPE; 669out_err: 670 return sent ? : err; 671} 672 673static int setsockopt(struct socket *sock, int lvl, int opt, sockptr_t ov, 674 unsigned int ol) 675{ 676 struct sock *sk = sock->sk; 677 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 678 int linksel; 679 680 if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED) 681 return -ENOPROTOOPT; 682 683 switch (opt) { 684 case CAIFSO_LINK_SELECT: 685 if (ol < sizeof(int)) 686 return -EINVAL; 687 if (lvl != SOL_CAIF) 688 goto bad_sol; 689 if (copy_from_sockptr(&linksel, ov, sizeof(int))) 690 return -EINVAL; 691 lock_sock(&(cf_sk->sk)); 692 cf_sk->conn_req.link_selector = linksel; 693 release_sock(&cf_sk->sk); 694 return 0; 695 696 case CAIFSO_REQ_PARAM: 697 if (lvl != SOL_CAIF) 698 goto bad_sol; 699 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL) 700 return -ENOPROTOOPT; 701 lock_sock(&(cf_sk->sk)); 702 if (ol > sizeof(cf_sk->conn_req.param.data) || 703 copy_from_sockptr(&cf_sk->conn_req.param.data, ov, ol)) { 704 release_sock(&cf_sk->sk); 705 return -EINVAL; 706 } 707 cf_sk->conn_req.param.size = ol; 708 release_sock(&cf_sk->sk); 709 return 0; 710 711 default: 712 return -ENOPROTOOPT; 713 } 714 715 return 0; 716bad_sol: 717 return -ENOPROTOOPT; 718 719} 720 721/* 722 * caif_connect() - Connect a CAIF Socket 723 * Copied and modified af_irda.c:irda_connect(). 724 * 725 * Note : by consulting "errno", the user space caller may learn the cause 726 * of the failure. Most of them are visible in the function, others may come 727 * from subroutines called and are listed here : 728 * o -EAFNOSUPPORT: bad socket family or type. 729 * o -ESOCKTNOSUPPORT: bad socket type or protocol 730 * o -EINVAL: bad socket address, or CAIF link type 731 * o -ECONNREFUSED: remote end refused the connection. 732 * o -EINPROGRESS: connect request sent but timed out (or non-blocking) 733 * o -EISCONN: already connected. 734 * o -ETIMEDOUT: Connection timed out (send timeout) 735 * o -ENODEV: No link layer to send request 736 * o -ECONNRESET: Received Shutdown indication or lost link layer 737 * o -ENOMEM: Out of memory 738 * 739 * State Strategy: 740 * o sk_state: holds the CAIF_* protocol state, it's updated by 741 * caif_ctrl_cb. 742 * o sock->state: holds the SS_* socket state and is updated by connect and 743 * disconnect. 744 */ 745static int caif_connect(struct socket *sock, struct sockaddr *uaddr, 746 int addr_len, int flags) 747{ 748 struct sock *sk = sock->sk; 749 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 750 long timeo; 751 int err; 752 int ifindex, headroom, tailroom; 753 unsigned int mtu; 754 struct net_device *dev; 755 756 lock_sock(sk); 757 758 err = -EINVAL; 759 if (addr_len < offsetofend(struct sockaddr, sa_family)) 760 goto out; 761 762 err = -EAFNOSUPPORT; 763 if (uaddr->sa_family != AF_CAIF) 764 goto out; 765 766 switch (sock->state) { 767 case SS_UNCONNECTED: 768 /* Normal case, a fresh connect */ 769 caif_assert(sk->sk_state == CAIF_DISCONNECTED); 770 break; 771 case SS_CONNECTING: 772 switch (sk->sk_state) { 773 case CAIF_CONNECTED: 774 sock->state = SS_CONNECTED; 775 err = -EISCONN; 776 goto out; 777 case CAIF_DISCONNECTED: 778 /* Reconnect allowed */ 779 break; 780 case CAIF_CONNECTING: 781 err = -EALREADY; 782 if (flags & O_NONBLOCK) 783 goto out; 784 goto wait_connect; 785 } 786 break; 787 case SS_CONNECTED: 788 caif_assert(sk->sk_state == CAIF_CONNECTED || 789 sk->sk_state == CAIF_DISCONNECTED); 790 if (sk->sk_shutdown & SHUTDOWN_MASK) { 791 /* Allow re-connect after SHUTDOWN_IND */ 792 caif_disconnect_client(sock_net(sk), &cf_sk->layer); 793 caif_free_client(&cf_sk->layer); 794 break; 795 } 796 /* No reconnect on a seqpacket socket */ 797 err = -EISCONN; 798 goto out; 799 case SS_DISCONNECTING: 800 case SS_FREE: 801 caif_assert(1); /*Should never happen */ 802 break; 803 } 804 sk->sk_state = CAIF_DISCONNECTED; 805 sock->state = SS_UNCONNECTED; 806 sk_stream_kill_queues(&cf_sk->sk); 807 808 err = -EINVAL; 809 if (addr_len != sizeof(struct sockaddr_caif)) 810 goto out; 811 812 memcpy(&cf_sk->conn_req.sockaddr, uaddr, 813 sizeof(struct sockaddr_caif)); 814 815 /* Move to connecting socket, start sending Connect Requests */ 816 sock->state = SS_CONNECTING; 817 sk->sk_state = CAIF_CONNECTING; 818 819 /* Check priority value comming from socket */ 820 /* if priority value is out of range it will be ajusted */ 821 if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX) 822 cf_sk->conn_req.priority = CAIF_PRIO_MAX; 823 else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN) 824 cf_sk->conn_req.priority = CAIF_PRIO_MIN; 825 else 826 cf_sk->conn_req.priority = cf_sk->sk.sk_priority; 827 828 /*ifindex = id of the interface.*/ 829 cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if; 830 831 cf_sk->layer.receive = caif_sktrecv_cb; 832 833 err = caif_connect_client(sock_net(sk), &cf_sk->conn_req, 834 &cf_sk->layer, &ifindex, &headroom, &tailroom); 835 836 if (err < 0) { 837 cf_sk->sk.sk_socket->state = SS_UNCONNECTED; 838 cf_sk->sk.sk_state = CAIF_DISCONNECTED; 839 goto out; 840 } 841 842 err = -ENODEV; 843 rcu_read_lock(); 844 dev = dev_get_by_index_rcu(sock_net(sk), ifindex); 845 if (!dev) { 846 rcu_read_unlock(); 847 goto out; 848 } 849 cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom); 850 mtu = dev->mtu; 851 rcu_read_unlock(); 852 853 cf_sk->tailroom = tailroom; 854 cf_sk->maxframe = mtu - (headroom + tailroom); 855 if (cf_sk->maxframe < 1) { 856 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu); 857 err = -ENODEV; 858 goto out; 859 } 860 861 err = -EINPROGRESS; 862wait_connect: 863 864 if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK)) 865 goto out; 866 867 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK); 868 869 release_sock(sk); 870 err = -ERESTARTSYS; 871 timeo = wait_event_interruptible_timeout(*sk_sleep(sk), 872 sk->sk_state != CAIF_CONNECTING, 873 timeo); 874 lock_sock(sk); 875 if (timeo < 0) 876 goto out; /* -ERESTARTSYS */ 877 878 err = -ETIMEDOUT; 879 if (timeo == 0 && sk->sk_state != CAIF_CONNECTED) 880 goto out; 881 if (sk->sk_state != CAIF_CONNECTED) { 882 sock->state = SS_UNCONNECTED; 883 err = sock_error(sk); 884 if (!err) 885 err = -ECONNREFUSED; 886 goto out; 887 } 888 sock->state = SS_CONNECTED; 889 err = 0; 890out: 891 release_sock(sk); 892 return err; 893} 894 895/* 896 * caif_release() - Disconnect a CAIF Socket 897 * Copied and modified af_irda.c:irda_release(). 898 */ 899static int caif_release(struct socket *sock) 900{ 901 struct sock *sk = sock->sk; 902 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 903 904 if (!sk) 905 return 0; 906 907 set_tx_flow_off(cf_sk); 908 909 /* 910 * Ensure that packets are not queued after this point in time. 911 * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock, 912 * this ensures no packets when sock is dead. 913 */ 914 spin_lock_bh(&sk->sk_receive_queue.lock); 915 sock_set_flag(sk, SOCK_DEAD); 916 spin_unlock_bh(&sk->sk_receive_queue.lock); 917 sock->sk = NULL; 918 919 WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir)); 920 debugfs_remove_recursive(cf_sk->debugfs_socket_dir); 921 922 lock_sock(&(cf_sk->sk)); 923 sk->sk_state = CAIF_DISCONNECTED; 924 sk->sk_shutdown = SHUTDOWN_MASK; 925 926 caif_disconnect_client(sock_net(sk), &cf_sk->layer); 927 cf_sk->sk.sk_socket->state = SS_DISCONNECTING; 928 wake_up_interruptible_poll(sk_sleep(sk), EPOLLERR|EPOLLHUP); 929 930 sock_orphan(sk); 931 sk_stream_kill_queues(&cf_sk->sk); 932 release_sock(sk); 933 sock_put(sk); 934 return 0; 935} 936 937/* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */ 938static __poll_t caif_poll(struct file *file, 939 struct socket *sock, poll_table *wait) 940{ 941 struct sock *sk = sock->sk; 942 __poll_t mask; 943 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 944 945 sock_poll_wait(file, sock, wait); 946 mask = 0; 947 948 /* exceptional events? */ 949 if (sk->sk_err) 950 mask |= EPOLLERR; 951 if (sk->sk_shutdown == SHUTDOWN_MASK) 952 mask |= EPOLLHUP; 953 if (sk->sk_shutdown & RCV_SHUTDOWN) 954 mask |= EPOLLRDHUP; 955 956 /* readable? */ 957 if (!skb_queue_empty_lockless(&sk->sk_receive_queue) || 958 (sk->sk_shutdown & RCV_SHUTDOWN)) 959 mask |= EPOLLIN | EPOLLRDNORM; 960 961 /* 962 * we set writable also when the other side has shut down the 963 * connection. This prevents stuck sockets. 964 */ 965 if (sock_writeable(sk) && tx_flow_is_on(cf_sk)) 966 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND; 967 968 return mask; 969} 970 971static const struct proto_ops caif_seqpacket_ops = { 972 .family = PF_CAIF, 973 .owner = THIS_MODULE, 974 .release = caif_release, 975 .bind = sock_no_bind, 976 .connect = caif_connect, 977 .socketpair = sock_no_socketpair, 978 .accept = sock_no_accept, 979 .getname = sock_no_getname, 980 .poll = caif_poll, 981 .ioctl = sock_no_ioctl, 982 .listen = sock_no_listen, 983 .shutdown = sock_no_shutdown, 984 .setsockopt = setsockopt, 985 .sendmsg = caif_seqpkt_sendmsg, 986 .recvmsg = caif_seqpkt_recvmsg, 987 .mmap = sock_no_mmap, 988 .sendpage = sock_no_sendpage, 989}; 990 991static 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 .sendmsg = caif_stream_sendmsg, 1006 .recvmsg = caif_stream_recvmsg, 1007 .mmap = sock_no_mmap, 1008 .sendpage = sock_no_sendpage, 1009}; 1010 1011/* This function is called when a socket is finally destroyed. */ 1012static void caif_sock_destructor(struct sock *sk) 1013{ 1014 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 1015 caif_assert(!refcount_read(&sk->sk_wmem_alloc)); 1016 caif_assert(sk_unhashed(sk)); 1017 caif_assert(!sk->sk_socket); 1018 if (!sock_flag(sk, SOCK_DEAD)) { 1019 pr_debug("Attempt to release alive CAIF socket: %p\n", sk); 1020 return; 1021 } 1022 sk_stream_kill_queues(&cf_sk->sk); 1023 WARN_ON(sk->sk_forward_alloc); 1024 caif_free_client(&cf_sk->layer); 1025} 1026 1027static 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 1108static const struct net_proto_family caif_family_ops = { 1109 .family = PF_CAIF, 1110 .create = caif_create, 1111 .owner = THIS_MODULE, 1112}; 1113 1114static int __init caif_sktinit_module(void) 1115{ 1116 return sock_register(&caif_family_ops); 1117} 1118 1119static void __exit caif_sktexit_module(void) 1120{ 1121 sock_unregister(PF_CAIF); 1122} 1123module_init(caif_sktinit_module); 1124module_exit(caif_sktexit_module); 1125