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