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 30MODULE_LICENSE("GPL"); 31MODULE_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 */ 38enum 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 47struct 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 57static int rx_flow_is_on(struct caifsock *cf_sk) 58{ 59 return test_bit(RX_FLOW_ON_BIT, &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, &cf_sk->flow_state); 65} 66 67static void set_rx_flow_off(struct caifsock *cf_sk) 68{ 69 clear_bit(RX_FLOW_ON_BIT, &cf_sk->flow_state); 70} 71 72static void set_rx_flow_on(struct caifsock *cf_sk) 73{ 74 set_bit(RX_FLOW_ON_BIT, &cf_sk->flow_state); 75} 76 77static void set_tx_flow_off(struct caifsock *cf_sk) 78{ 79 clear_bit(TX_FLOW_ON_BIT, &cf_sk->flow_state); 80} 81 82static void set_tx_flow_on(struct caifsock *cf_sk) 83{ 84 set_bit(TX_FLOW_ON_BIT, &cf_sk->flow_state); 85} 86 87static 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 94static 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 101static 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 107static 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 */ 119static 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); 152out: 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 */ 160static 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 176static 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 182static 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 */ 189static 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 249static 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 */ 266static 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; 293out_free: 294 skb_free_datagram(sk, skb); 295 caif_check_flow_release(sk); 296 return ret; 297 298read_error: 299 return ret; 300} 301 302 303/* Copied from unix_stream_wait_data, identical except for lock call. */ 304static 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 */ 342static 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; 414unlock: 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 451out: 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 */ 459static 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 */ 495static 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 */ 513static 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 noblock = msg->msg_flags & MSG_DONTWAIT; 537 538 timeo = sock_sndtimeo(sk, noblock); 539 timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk), 540 1, timeo, &ret); 541 542 if (ret) 543 goto err; 544 ret = -EPIPE; 545 if (cf_sk->sk.sk_state != CAIF_CONNECTED || 546 sock_flag(sk, SOCK_DEAD) || 547 (sk->sk_shutdown & RCV_SHUTDOWN)) 548 goto err; 549 550 /* Error if trying to write more than maximum frame size. */ 551 ret = -EMSGSIZE; 552 if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM) 553 goto err; 554 555 buffer_size = len + cf_sk->headroom + cf_sk->tailroom; 556 557 ret = -ENOMEM; 558 skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret); 559 560 if (!skb || skb_tailroom(skb) < buffer_size) 561 goto err; 562 563 skb_reserve(skb, cf_sk->headroom); 564 565 ret = memcpy_from_msg(skb_put(skb, len), msg, len); 566 567 if (ret) 568 goto err; 569 ret = transmit_skb(skb, cf_sk, noblock, timeo); 570 if (ret < 0) 571 /* skb is already freed */ 572 return ret; 573 574 return len; 575err: 576 kfree_skb(skb); 577 return ret; 578} 579 580/* 581 * Copied from unix_stream_sendmsg and adapted to CAIF: 582 * Changed removed permission handling and added waiting for flow on 583 * and other minor adaptations. 584 */ 585static int caif_stream_sendmsg(struct socket *sock, struct msghdr *msg, 586 size_t len) 587{ 588 struct sock *sk = sock->sk; 589 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 590 int err, size; 591 struct sk_buff *skb; 592 int sent = 0; 593 long timeo; 594 595 err = -EOPNOTSUPP; 596 if (unlikely(msg->msg_flags&MSG_OOB)) 597 goto out_err; 598 599 if (unlikely(msg->msg_namelen)) 600 goto out_err; 601 602 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 603 timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err); 604 605 if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN)) 606 goto pipe_err; 607 608 while (sent < len) { 609 610 size = len-sent; 611 612 if (size > cf_sk->maxframe) 613 size = cf_sk->maxframe; 614 615 /* If size is more than half of sndbuf, chop up message */ 616 if (size > ((sk->sk_sndbuf >> 1) - 64)) 617 size = (sk->sk_sndbuf >> 1) - 64; 618 619 if (size > SKB_MAX_ALLOC) 620 size = SKB_MAX_ALLOC; 621 622 skb = sock_alloc_send_skb(sk, 623 size + cf_sk->headroom + 624 cf_sk->tailroom, 625 msg->msg_flags&MSG_DONTWAIT, 626 &err); 627 if (skb == NULL) 628 goto out_err; 629 630 skb_reserve(skb, cf_sk->headroom); 631 /* 632 * If you pass two values to the sock_alloc_send_skb 633 * it tries to grab the large buffer with GFP_NOFS 634 * (which can fail easily), and if it fails grab the 635 * fallback size buffer which is under a page and will 636 * succeed. [Alan] 637 */ 638 size = min_t(int, size, skb_tailroom(skb)); 639 640 err = memcpy_from_msg(skb_put(skb, size), msg, size); 641 if (err) { 642 kfree_skb(skb); 643 goto out_err; 644 } 645 err = transmit_skb(skb, cf_sk, 646 msg->msg_flags&MSG_DONTWAIT, timeo); 647 if (err < 0) 648 /* skb is already freed */ 649 goto pipe_err; 650 651 sent += size; 652 } 653 654 return sent; 655 656pipe_err: 657 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL)) 658 send_sig(SIGPIPE, current, 0); 659 err = -EPIPE; 660out_err: 661 return sent ? : err; 662} 663 664static int setsockopt(struct socket *sock, int lvl, int opt, sockptr_t ov, 665 unsigned int ol) 666{ 667 struct sock *sk = sock->sk; 668 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 669 int linksel; 670 671 if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED) 672 return -ENOPROTOOPT; 673 674 switch (opt) { 675 case CAIFSO_LINK_SELECT: 676 if (ol < sizeof(int)) 677 return -EINVAL; 678 if (lvl != SOL_CAIF) 679 goto bad_sol; 680 if (copy_from_sockptr(&linksel, ov, sizeof(int))) 681 return -EINVAL; 682 lock_sock(&(cf_sk->sk)); 683 cf_sk->conn_req.link_selector = linksel; 684 release_sock(&cf_sk->sk); 685 return 0; 686 687 case CAIFSO_REQ_PARAM: 688 if (lvl != SOL_CAIF) 689 goto bad_sol; 690 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL) 691 return -ENOPROTOOPT; 692 lock_sock(&(cf_sk->sk)); 693 if (ol > sizeof(cf_sk->conn_req.param.data) || 694 copy_from_sockptr(&cf_sk->conn_req.param.data, ov, ol)) { 695 release_sock(&cf_sk->sk); 696 return -EINVAL; 697 } 698 cf_sk->conn_req.param.size = ol; 699 release_sock(&cf_sk->sk); 700 return 0; 701 702 default: 703 return -ENOPROTOOPT; 704 } 705 706 return 0; 707bad_sol: 708 return -ENOPROTOOPT; 709 710} 711 712/* 713 * caif_connect() - Connect a CAIF Socket 714 * Copied and modified af_irda.c:irda_connect(). 715 * 716 * Note : by consulting "errno", the user space caller may learn the cause 717 * of the failure. Most of them are visible in the function, others may come 718 * from subroutines called and are listed here : 719 * o -EAFNOSUPPORT: bad socket family or type. 720 * o -ESOCKTNOSUPPORT: bad socket type or protocol 721 * o -EINVAL: bad socket address, or CAIF link type 722 * o -ECONNREFUSED: remote end refused the connection. 723 * o -EINPROGRESS: connect request sent but timed out (or non-blocking) 724 * o -EISCONN: already connected. 725 * o -ETIMEDOUT: Connection timed out (send timeout) 726 * o -ENODEV: No link layer to send request 727 * o -ECONNRESET: Received Shutdown indication or lost link layer 728 * o -ENOMEM: Out of memory 729 * 730 * State Strategy: 731 * o sk_state: holds the CAIF_* protocol state, it's updated by 732 * caif_ctrl_cb. 733 * o sock->state: holds the SS_* socket state and is updated by connect and 734 * disconnect. 735 */ 736static int caif_connect(struct socket *sock, struct sockaddr *uaddr, 737 int addr_len, int flags) 738{ 739 struct sock *sk = sock->sk; 740 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 741 long timeo; 742 int err; 743 int ifindex, headroom, tailroom; 744 unsigned int mtu; 745 struct net_device *dev; 746 747 lock_sock(sk); 748 749 err = -EINVAL; 750 if (addr_len < offsetofend(struct sockaddr, sa_family)) 751 goto out; 752 753 err = -EAFNOSUPPORT; 754 if (uaddr->sa_family != AF_CAIF) 755 goto out; 756 757 switch (sock->state) { 758 case SS_UNCONNECTED: 759 /* Normal case, a fresh connect */ 760 caif_assert(sk->sk_state == CAIF_DISCONNECTED); 761 break; 762 case SS_CONNECTING: 763 switch (sk->sk_state) { 764 case CAIF_CONNECTED: 765 sock->state = SS_CONNECTED; 766 err = -EISCONN; 767 goto out; 768 case CAIF_DISCONNECTED: 769 /* Reconnect allowed */ 770 break; 771 case CAIF_CONNECTING: 772 err = -EALREADY; 773 if (flags & O_NONBLOCK) 774 goto out; 775 goto wait_connect; 776 } 777 break; 778 case SS_CONNECTED: 779 caif_assert(sk->sk_state == CAIF_CONNECTED || 780 sk->sk_state == CAIF_DISCONNECTED); 781 if (sk->sk_shutdown & SHUTDOWN_MASK) { 782 /* Allow re-connect after SHUTDOWN_IND */ 783 caif_disconnect_client(sock_net(sk), &cf_sk->layer); 784 caif_free_client(&cf_sk->layer); 785 break; 786 } 787 /* No reconnect on a seqpacket socket */ 788 err = -EISCONN; 789 goto out; 790 case SS_DISCONNECTING: 791 case SS_FREE: 792 caif_assert(1); /*Should never happen */ 793 break; 794 } 795 sk->sk_state = CAIF_DISCONNECTED; 796 sock->state = SS_UNCONNECTED; 797 sk_stream_kill_queues(&cf_sk->sk); 798 799 err = -EINVAL; 800 if (addr_len != sizeof(struct sockaddr_caif)) 801 goto out; 802 803 memcpy(&cf_sk->conn_req.sockaddr, uaddr, 804 sizeof(struct sockaddr_caif)); 805 806 /* Move to connecting socket, start sending Connect Requests */ 807 sock->state = SS_CONNECTING; 808 sk->sk_state = CAIF_CONNECTING; 809 810 /* Check priority value comming from socket */ 811 /* if priority value is out of range it will be ajusted */ 812 if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX) 813 cf_sk->conn_req.priority = CAIF_PRIO_MAX; 814 else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN) 815 cf_sk->conn_req.priority = CAIF_PRIO_MIN; 816 else 817 cf_sk->conn_req.priority = cf_sk->sk.sk_priority; 818 819 /*ifindex = id of the interface.*/ 820 cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if; 821 822 cf_sk->layer.receive = caif_sktrecv_cb; 823 824 err = caif_connect_client(sock_net(sk), &cf_sk->conn_req, 825 &cf_sk->layer, &ifindex, &headroom, &tailroom); 826 827 if (err < 0) { 828 cf_sk->sk.sk_socket->state = SS_UNCONNECTED; 829 cf_sk->sk.sk_state = CAIF_DISCONNECTED; 830 goto out; 831 } 832 833 err = -ENODEV; 834 rcu_read_lock(); 835 dev = dev_get_by_index_rcu(sock_net(sk), ifindex); 836 if (!dev) { 837 rcu_read_unlock(); 838 goto out; 839 } 840 cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom); 841 mtu = dev->mtu; 842 rcu_read_unlock(); 843 844 cf_sk->tailroom = tailroom; 845 cf_sk->maxframe = mtu - (headroom + tailroom); 846 if (cf_sk->maxframe < 1) { 847 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu); 848 err = -ENODEV; 849 goto out; 850 } 851 852 err = -EINPROGRESS; 853wait_connect: 854 855 if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK)) 856 goto out; 857 858 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK); 859 860 release_sock(sk); 861 err = -ERESTARTSYS; 862 timeo = wait_event_interruptible_timeout(*sk_sleep(sk), 863 sk->sk_state != CAIF_CONNECTING, 864 timeo); 865 lock_sock(sk); 866 if (timeo < 0) 867 goto out; /* -ERESTARTSYS */ 868 869 err = -ETIMEDOUT; 870 if (timeo == 0 && sk->sk_state != CAIF_CONNECTED) 871 goto out; 872 if (sk->sk_state != CAIF_CONNECTED) { 873 sock->state = SS_UNCONNECTED; 874 err = sock_error(sk); 875 if (!err) 876 err = -ECONNREFUSED; 877 goto out; 878 } 879 sock->state = SS_CONNECTED; 880 err = 0; 881out: 882 release_sock(sk); 883 return err; 884} 885 886/* 887 * caif_release() - Disconnect a CAIF Socket 888 * Copied and modified af_irda.c:irda_release(). 889 */ 890static int caif_release(struct socket *sock) 891{ 892 struct sock *sk = sock->sk; 893 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 894 895 if (!sk) 896 return 0; 897 898 set_tx_flow_off(cf_sk); 899 900 /* 901 * Ensure that packets are not queued after this point in time. 902 * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock, 903 * this ensures no packets when sock is dead. 904 */ 905 spin_lock_bh(&sk->sk_receive_queue.lock); 906 sock_set_flag(sk, SOCK_DEAD); 907 spin_unlock_bh(&sk->sk_receive_queue.lock); 908 sock->sk = NULL; 909 910 WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir)); 911 debugfs_remove_recursive(cf_sk->debugfs_socket_dir); 912 913 lock_sock(&(cf_sk->sk)); 914 sk->sk_state = CAIF_DISCONNECTED; 915 sk->sk_shutdown = SHUTDOWN_MASK; 916 917 caif_disconnect_client(sock_net(sk), &cf_sk->layer); 918 cf_sk->sk.sk_socket->state = SS_DISCONNECTING; 919 wake_up_interruptible_poll(sk_sleep(sk), EPOLLERR|EPOLLHUP); 920 921 sock_orphan(sk); 922 sk_stream_kill_queues(&cf_sk->sk); 923 release_sock(sk); 924 sock_put(sk); 925 return 0; 926} 927 928/* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */ 929static __poll_t caif_poll(struct file *file, 930 struct socket *sock, poll_table *wait) 931{ 932 struct sock *sk = sock->sk; 933 __poll_t mask; 934 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 935 936 sock_poll_wait(file, sock, wait); 937 mask = 0; 938 939 /* exceptional events? */ 940 if (sk->sk_err) 941 mask |= EPOLLERR; 942 if (sk->sk_shutdown == SHUTDOWN_MASK) 943 mask |= EPOLLHUP; 944 if (sk->sk_shutdown & RCV_SHUTDOWN) 945 mask |= EPOLLRDHUP; 946 947 /* readable? */ 948 if (!skb_queue_empty_lockless(&sk->sk_receive_queue) || 949 (sk->sk_shutdown & RCV_SHUTDOWN)) 950 mask |= EPOLLIN | EPOLLRDNORM; 951 952 /* 953 * we set writable also when the other side has shut down the 954 * connection. This prevents stuck sockets. 955 */ 956 if (sock_writeable(sk) && tx_flow_is_on(cf_sk)) 957 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND; 958 959 return mask; 960} 961 962static const struct proto_ops caif_seqpacket_ops = { 963 .family = PF_CAIF, 964 .owner = THIS_MODULE, 965 .release = caif_release, 966 .bind = sock_no_bind, 967 .connect = caif_connect, 968 .socketpair = sock_no_socketpair, 969 .accept = sock_no_accept, 970 .getname = sock_no_getname, 971 .poll = caif_poll, 972 .ioctl = sock_no_ioctl, 973 .listen = sock_no_listen, 974 .shutdown = sock_no_shutdown, 975 .setsockopt = setsockopt, 976 .sendmsg = caif_seqpkt_sendmsg, 977 .recvmsg = caif_seqpkt_recvmsg, 978 .mmap = sock_no_mmap, 979}; 980 981static const struct proto_ops caif_stream_ops = { 982 .family = PF_CAIF, 983 .owner = THIS_MODULE, 984 .release = caif_release, 985 .bind = sock_no_bind, 986 .connect = caif_connect, 987 .socketpair = sock_no_socketpair, 988 .accept = sock_no_accept, 989 .getname = sock_no_getname, 990 .poll = caif_poll, 991 .ioctl = sock_no_ioctl, 992 .listen = sock_no_listen, 993 .shutdown = sock_no_shutdown, 994 .setsockopt = setsockopt, 995 .sendmsg = caif_stream_sendmsg, 996 .recvmsg = caif_stream_recvmsg, 997 .mmap = sock_no_mmap, 998}; 999 1000/* This function is called when a socket is finally destroyed. */ 1001static void caif_sock_destructor(struct sock *sk) 1002{ 1003 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 1004 caif_assert(!refcount_read(&sk->sk_wmem_alloc)); 1005 caif_assert(sk_unhashed(sk)); 1006 caif_assert(!sk->sk_socket); 1007 if (!sock_flag(sk, SOCK_DEAD)) { 1008 pr_debug("Attempt to release alive CAIF socket: %p\n", sk); 1009 return; 1010 } 1011 sk_stream_kill_queues(&cf_sk->sk); 1012 WARN_ON_ONCE(sk->sk_forward_alloc); 1013 caif_free_client(&cf_sk->layer); 1014} 1015 1016static int caif_create(struct net *net, struct socket *sock, int protocol, 1017 int kern) 1018{ 1019 struct sock *sk = NULL; 1020 struct caifsock *cf_sk = NULL; 1021 static struct proto prot = {.name = "PF_CAIF", 1022 .owner = THIS_MODULE, 1023 .obj_size = sizeof(struct caifsock), 1024 .useroffset = offsetof(struct caifsock, conn_req.param), 1025 .usersize = sizeof_field(struct caifsock, conn_req.param) 1026 }; 1027 1028 if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN)) 1029 return -EPERM; 1030 /* 1031 * The sock->type specifies the socket type to use. 1032 * The CAIF socket is a packet stream in the sense 1033 * that it is packet based. CAIF trusts the reliability 1034 * of the link, no resending is implemented. 1035 */ 1036 if (sock->type == SOCK_SEQPACKET) 1037 sock->ops = &caif_seqpacket_ops; 1038 else if (sock->type == SOCK_STREAM) 1039 sock->ops = &caif_stream_ops; 1040 else 1041 return -ESOCKTNOSUPPORT; 1042 1043 if (protocol < 0 || protocol >= CAIFPROTO_MAX) 1044 return -EPROTONOSUPPORT; 1045 /* 1046 * Set the socket state to unconnected. The socket state 1047 * is really not used at all in the net/core or socket.c but the 1048 * initialization makes sure that sock->state is not uninitialized. 1049 */ 1050 sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot, kern); 1051 if (!sk) 1052 return -ENOMEM; 1053 1054 cf_sk = container_of(sk, struct caifsock, sk); 1055 1056 /* Store the protocol */ 1057 sk->sk_protocol = (unsigned char) protocol; 1058 1059 /* Initialize default priority for well-known cases */ 1060 switch (protocol) { 1061 case CAIFPROTO_AT: 1062 sk->sk_priority = TC_PRIO_CONTROL; 1063 break; 1064 case CAIFPROTO_RFM: 1065 sk->sk_priority = TC_PRIO_INTERACTIVE_BULK; 1066 break; 1067 default: 1068 sk->sk_priority = TC_PRIO_BESTEFFORT; 1069 } 1070 1071 /* 1072 * Lock in order to try to stop someone from opening the socket 1073 * too early. 1074 */ 1075 lock_sock(&(cf_sk->sk)); 1076 1077 /* Initialize the nozero default sock structure data. */ 1078 sock_init_data(sock, sk); 1079 sk->sk_destruct = caif_sock_destructor; 1080 1081 mutex_init(&cf_sk->readlock); /* single task reading lock */ 1082 cf_sk->layer.ctrlcmd = caif_ctrl_cb; 1083 cf_sk->sk.sk_socket->state = SS_UNCONNECTED; 1084 cf_sk->sk.sk_state = CAIF_DISCONNECTED; 1085 1086 set_tx_flow_off(cf_sk); 1087 set_rx_flow_on(cf_sk); 1088 1089 /* Set default options on configuration */ 1090 cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY; 1091 cf_sk->conn_req.protocol = protocol; 1092 release_sock(&cf_sk->sk); 1093 return 0; 1094} 1095 1096 1097static const struct net_proto_family caif_family_ops = { 1098 .family = PF_CAIF, 1099 .create = caif_create, 1100 .owner = THIS_MODULE, 1101}; 1102 1103static int __init caif_sktinit_module(void) 1104{ 1105 return sock_register(&caif_family_ops); 1106} 1107 1108static void __exit caif_sktexit_module(void) 1109{ 1110 sock_unregister(PF_CAIF); 1111} 1112module_init(caif_sktinit_module); 1113module_exit(caif_sktexit_module); 1114