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_DESCRIPTION("ST-Ericsson CAIF modem protocol socket support (AF_CAIF)"); 31MODULE_LICENSE("GPL"); 32MODULE_ALIAS_NETPROTO(AF_CAIF); 33 34/* 35 * CAIF state is re-using the TCP socket states. 36 * caif_states stored in sk_state reflect the state as reported by 37 * the CAIF stack, while sk_socket->state is the state of the socket. 38 */ 39enum caif_states { 40 CAIF_CONNECTED = TCP_ESTABLISHED, 41 CAIF_CONNECTING = TCP_SYN_SENT, 42 CAIF_DISCONNECTED = TCP_CLOSE 43}; 44 45#define TX_FLOW_ON_BIT 1 46#define RX_FLOW_ON_BIT 2 47 48struct caifsock { 49 struct sock sk; /* must be first member */ 50 struct cflayer layer; 51 unsigned long flow_state; 52 struct caif_connect_request conn_req; 53 struct mutex readlock; 54 struct dentry *debugfs_socket_dir; 55 int headroom, tailroom, maxframe; 56}; 57 58static int rx_flow_is_on(struct caifsock *cf_sk) 59{ 60 return test_bit(RX_FLOW_ON_BIT, &cf_sk->flow_state); 61} 62 63static int tx_flow_is_on(struct caifsock *cf_sk) 64{ 65 return test_bit(TX_FLOW_ON_BIT, &cf_sk->flow_state); 66} 67 68static void set_rx_flow_off(struct caifsock *cf_sk) 69{ 70 clear_bit(RX_FLOW_ON_BIT, &cf_sk->flow_state); 71} 72 73static void set_rx_flow_on(struct caifsock *cf_sk) 74{ 75 set_bit(RX_FLOW_ON_BIT, &cf_sk->flow_state); 76} 77 78static void set_tx_flow_off(struct caifsock *cf_sk) 79{ 80 clear_bit(TX_FLOW_ON_BIT, &cf_sk->flow_state); 81} 82 83static void set_tx_flow_on(struct caifsock *cf_sk) 84{ 85 set_bit(TX_FLOW_ON_BIT, &cf_sk->flow_state); 86} 87 88static void caif_read_lock(struct sock *sk) 89{ 90 struct caifsock *cf_sk; 91 cf_sk = container_of(sk, struct caifsock, sk); 92 mutex_lock(&cf_sk->readlock); 93} 94 95static void caif_read_unlock(struct sock *sk) 96{ 97 struct caifsock *cf_sk; 98 cf_sk = container_of(sk, struct caifsock, sk); 99 mutex_unlock(&cf_sk->readlock); 100} 101 102static int sk_rcvbuf_lowwater(struct caifsock *cf_sk) 103{ 104 /* A quarter of full buffer is used a low water mark */ 105 return cf_sk->sk.sk_rcvbuf / 4; 106} 107 108static void caif_flow_ctrl(struct sock *sk, int mode) 109{ 110 struct caifsock *cf_sk; 111 cf_sk = container_of(sk, struct caifsock, sk); 112 if (cf_sk->layer.dn && cf_sk->layer.dn->modemcmd) 113 cf_sk->layer.dn->modemcmd(cf_sk->layer.dn, mode); 114} 115 116/* 117 * Copied from sock.c:sock_queue_rcv_skb(), but changed so packets are 118 * not dropped, but CAIF is sending flow off instead. 119 */ 120static void caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) 121{ 122 int err; 123 unsigned long flags; 124 struct sk_buff_head *list = &sk->sk_receive_queue; 125 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 126 bool queued = false; 127 128 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >= 129 (unsigned int)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) { 130 net_dbg_ratelimited("sending flow OFF (queue len = %d %d)\n", 131 atomic_read(&cf_sk->sk.sk_rmem_alloc), 132 sk_rcvbuf_lowwater(cf_sk)); 133 set_rx_flow_off(cf_sk); 134 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ); 135 } 136 137 err = sk_filter(sk, skb); 138 if (err) 139 goto out; 140 141 if (!sk_rmem_schedule(sk, skb, skb->truesize) && rx_flow_is_on(cf_sk)) { 142 set_rx_flow_off(cf_sk); 143 net_dbg_ratelimited("sending flow OFF due to rmem_schedule\n"); 144 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ); 145 } 146 skb->dev = NULL; 147 skb_set_owner_r(skb, sk); 148 spin_lock_irqsave(&list->lock, flags); 149 queued = !sock_flag(sk, SOCK_DEAD); 150 if (queued) 151 __skb_queue_tail(list, skb); 152 spin_unlock_irqrestore(&list->lock, flags); 153out: 154 if (queued) 155 sk->sk_data_ready(sk); 156 else 157 kfree_skb(skb); 158} 159 160/* Packet Receive Callback function called from CAIF Stack */ 161static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt) 162{ 163 struct caifsock *cf_sk; 164 struct sk_buff *skb; 165 166 cf_sk = container_of(layr, struct caifsock, layer); 167 skb = cfpkt_tonative(pkt); 168 169 if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) { 170 kfree_skb(skb); 171 return 0; 172 } 173 caif_queue_rcv_skb(&cf_sk->sk, skb); 174 return 0; 175} 176 177static void cfsk_hold(struct cflayer *layr) 178{ 179 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer); 180 sock_hold(&cf_sk->sk); 181} 182 183static void cfsk_put(struct cflayer *layr) 184{ 185 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer); 186 sock_put(&cf_sk->sk); 187} 188 189/* Packet Control Callback function called from CAIF */ 190static void caif_ctrl_cb(struct cflayer *layr, 191 enum caif_ctrlcmd flow, 192 int phyid) 193{ 194 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer); 195 switch (flow) { 196 case CAIF_CTRLCMD_FLOW_ON_IND: 197 /* OK from modem to start sending again */ 198 set_tx_flow_on(cf_sk); 199 cf_sk->sk.sk_state_change(&cf_sk->sk); 200 break; 201 202 case CAIF_CTRLCMD_FLOW_OFF_IND: 203 /* Modem asks us to shut up */ 204 set_tx_flow_off(cf_sk); 205 cf_sk->sk.sk_state_change(&cf_sk->sk); 206 break; 207 208 case CAIF_CTRLCMD_INIT_RSP: 209 /* We're now connected */ 210 caif_client_register_refcnt(&cf_sk->layer, 211 cfsk_hold, cfsk_put); 212 cf_sk->sk.sk_state = CAIF_CONNECTED; 213 set_tx_flow_on(cf_sk); 214 cf_sk->sk.sk_shutdown = 0; 215 cf_sk->sk.sk_state_change(&cf_sk->sk); 216 break; 217 218 case CAIF_CTRLCMD_DEINIT_RSP: 219 /* We're now disconnected */ 220 cf_sk->sk.sk_state = CAIF_DISCONNECTED; 221 cf_sk->sk.sk_state_change(&cf_sk->sk); 222 break; 223 224 case CAIF_CTRLCMD_INIT_FAIL_RSP: 225 /* Connect request failed */ 226 cf_sk->sk.sk_err = ECONNREFUSED; 227 cf_sk->sk.sk_state = CAIF_DISCONNECTED; 228 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK; 229 /* 230 * Socket "standards" seems to require POLLOUT to 231 * be set at connect failure. 232 */ 233 set_tx_flow_on(cf_sk); 234 cf_sk->sk.sk_state_change(&cf_sk->sk); 235 break; 236 237 case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND: 238 /* Modem has closed this connection, or device is down. */ 239 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK; 240 cf_sk->sk.sk_err = ECONNRESET; 241 set_rx_flow_on(cf_sk); 242 sk_error_report(&cf_sk->sk); 243 break; 244 245 default: 246 pr_debug("Unexpected flow command %d\n", flow); 247 } 248} 249 250static void caif_check_flow_release(struct sock *sk) 251{ 252 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 253 254 if (rx_flow_is_on(cf_sk)) 255 return; 256 257 if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) { 258 set_rx_flow_on(cf_sk); 259 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ); 260 } 261} 262 263/* 264 * Copied from unix_dgram_recvmsg, but removed credit checks, 265 * changed locking, address handling and added MSG_TRUNC. 266 */ 267static int caif_seqpkt_recvmsg(struct socket *sock, struct msghdr *m, 268 size_t len, int flags) 269 270{ 271 struct sock *sk = sock->sk; 272 struct sk_buff *skb; 273 int ret; 274 int copylen; 275 276 ret = -EOPNOTSUPP; 277 if (flags & MSG_OOB) 278 goto read_error; 279 280 skb = skb_recv_datagram(sk, flags, &ret); 281 if (!skb) 282 goto read_error; 283 copylen = skb->len; 284 if (len < copylen) { 285 m->msg_flags |= MSG_TRUNC; 286 copylen = len; 287 } 288 289 ret = skb_copy_datagram_msg(skb, 0, m, copylen); 290 if (ret) 291 goto out_free; 292 293 ret = (flags & MSG_TRUNC) ? skb->len : copylen; 294out_free: 295 skb_free_datagram(sk, skb); 296 caif_check_flow_release(sk); 297 return ret; 298 299read_error: 300 return ret; 301} 302 303 304/* Copied from unix_stream_wait_data, identical except for lock call. */ 305static long caif_stream_data_wait(struct sock *sk, long timeo) 306{ 307 DEFINE_WAIT(wait); 308 lock_sock(sk); 309 310 for (;;) { 311 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); 312 313 if (!skb_queue_empty(&sk->sk_receive_queue) || 314 sk->sk_err || 315 sk->sk_state != CAIF_CONNECTED || 316 sock_flag(sk, SOCK_DEAD) || 317 (sk->sk_shutdown & RCV_SHUTDOWN) || 318 signal_pending(current) || 319 !timeo) 320 break; 321 322 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); 323 release_sock(sk); 324 timeo = schedule_timeout(timeo); 325 lock_sock(sk); 326 327 if (sock_flag(sk, SOCK_DEAD)) 328 break; 329 330 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); 331 } 332 333 finish_wait(sk_sleep(sk), &wait); 334 release_sock(sk); 335 return timeo; 336} 337 338 339/* 340 * Copied from unix_stream_recvmsg, but removed credit checks, 341 * changed locking calls, changed address handling. 342 */ 343static int caif_stream_recvmsg(struct socket *sock, struct msghdr *msg, 344 size_t size, int flags) 345{ 346 struct sock *sk = sock->sk; 347 int copied = 0; 348 int target; 349 int err = 0; 350 long timeo; 351 352 err = -EOPNOTSUPP; 353 if (flags&MSG_OOB) 354 goto out; 355 356 /* 357 * Lock the socket to prevent queue disordering 358 * while sleeps in memcpy_tomsg 359 */ 360 err = -EAGAIN; 361 if (sk->sk_state == CAIF_CONNECTING) 362 goto out; 363 364 caif_read_lock(sk); 365 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size); 366 timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT); 367 368 do { 369 int chunk; 370 struct sk_buff *skb; 371 372 lock_sock(sk); 373 if (sock_flag(sk, SOCK_DEAD)) { 374 err = -ECONNRESET; 375 goto unlock; 376 } 377 skb = skb_dequeue(&sk->sk_receive_queue); 378 caif_check_flow_release(sk); 379 380 if (skb == NULL) { 381 if (copied >= target) 382 goto unlock; 383 /* 384 * POSIX 1003.1g mandates this order. 385 */ 386 err = sock_error(sk); 387 if (err) 388 goto unlock; 389 err = -ECONNRESET; 390 if (sk->sk_shutdown & RCV_SHUTDOWN) 391 goto unlock; 392 393 err = -EPIPE; 394 if (sk->sk_state != CAIF_CONNECTED) 395 goto unlock; 396 if (sock_flag(sk, SOCK_DEAD)) 397 goto unlock; 398 399 release_sock(sk); 400 401 err = -EAGAIN; 402 if (!timeo) 403 break; 404 405 caif_read_unlock(sk); 406 407 timeo = caif_stream_data_wait(sk, timeo); 408 409 if (signal_pending(current)) { 410 err = sock_intr_errno(timeo); 411 goto out; 412 } 413 caif_read_lock(sk); 414 continue; 415unlock: 416 release_sock(sk); 417 break; 418 } 419 release_sock(sk); 420 chunk = min_t(unsigned int, skb->len, size); 421 if (memcpy_to_msg(msg, skb->data, chunk)) { 422 skb_queue_head(&sk->sk_receive_queue, skb); 423 if (copied == 0) 424 copied = -EFAULT; 425 break; 426 } 427 copied += chunk; 428 size -= chunk; 429 430 /* Mark read part of skb as used */ 431 if (!(flags & MSG_PEEK)) { 432 skb_pull(skb, chunk); 433 434 /* put the skb back if we didn't use it up. */ 435 if (skb->len) { 436 skb_queue_head(&sk->sk_receive_queue, skb); 437 break; 438 } 439 kfree_skb(skb); 440 441 } else { 442 /* 443 * It is questionable, see note in unix_dgram_recvmsg. 444 */ 445 /* put message back and return */ 446 skb_queue_head(&sk->sk_receive_queue, skb); 447 break; 448 } 449 } while (size); 450 caif_read_unlock(sk); 451 452out: 453 return copied ? : err; 454} 455 456/* 457 * Copied from sock.c:sock_wait_for_wmem, but change to wait for 458 * CAIF flow-on and sock_writable. 459 */ 460static long caif_wait_for_flow_on(struct caifsock *cf_sk, 461 int wait_writeable, long timeo, int *err) 462{ 463 struct sock *sk = &cf_sk->sk; 464 DEFINE_WAIT(wait); 465 for (;;) { 466 *err = 0; 467 if (tx_flow_is_on(cf_sk) && 468 (!wait_writeable || sock_writeable(&cf_sk->sk))) 469 break; 470 *err = -ETIMEDOUT; 471 if (!timeo) 472 break; 473 *err = -ERESTARTSYS; 474 if (signal_pending(current)) 475 break; 476 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); 477 *err = -ECONNRESET; 478 if (sk->sk_shutdown & SHUTDOWN_MASK) 479 break; 480 *err = -sk->sk_err; 481 if (sk->sk_err) 482 break; 483 *err = -EPIPE; 484 if (cf_sk->sk.sk_state != CAIF_CONNECTED) 485 break; 486 timeo = schedule_timeout(timeo); 487 } 488 finish_wait(sk_sleep(sk), &wait); 489 return timeo; 490} 491 492/* 493 * Transmit a SKB. The device may temporarily request re-transmission 494 * by returning EAGAIN. 495 */ 496static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk, 497 int noblock, long timeo) 498{ 499 struct cfpkt *pkt; 500 501 pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb); 502 memset(skb->cb, 0, sizeof(struct caif_payload_info)); 503 cfpkt_set_prio(pkt, cf_sk->sk.sk_priority); 504 505 if (cf_sk->layer.dn == NULL) { 506 kfree_skb(skb); 507 return -EINVAL; 508 } 509 510 return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt); 511} 512 513/* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */ 514static int caif_seqpkt_sendmsg(struct socket *sock, struct msghdr *msg, 515 size_t len) 516{ 517 struct sock *sk = sock->sk; 518 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 519 int buffer_size; 520 int ret = 0; 521 struct sk_buff *skb = NULL; 522 int noblock; 523 long timeo; 524 caif_assert(cf_sk); 525 ret = sock_error(sk); 526 if (ret) 527 goto err; 528 529 ret = -EOPNOTSUPP; 530 if (msg->msg_flags&MSG_OOB) 531 goto err; 532 533 ret = -EOPNOTSUPP; 534 if (msg->msg_namelen) 535 goto err; 536 537 noblock = msg->msg_flags & MSG_DONTWAIT; 538 539 timeo = sock_sndtimeo(sk, noblock); 540 timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk), 541 1, timeo, &ret); 542 543 if (ret) 544 goto err; 545 ret = -EPIPE; 546 if (cf_sk->sk.sk_state != CAIF_CONNECTED || 547 sock_flag(sk, SOCK_DEAD) || 548 (sk->sk_shutdown & RCV_SHUTDOWN)) 549 goto err; 550 551 /* Error if trying to write more than maximum frame size. */ 552 ret = -EMSGSIZE; 553 if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM) 554 goto err; 555 556 buffer_size = len + cf_sk->headroom + cf_sk->tailroom; 557 558 ret = -ENOMEM; 559 skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret); 560 561 if (!skb || skb_tailroom(skb) < buffer_size) 562 goto err; 563 564 skb_reserve(skb, cf_sk->headroom); 565 566 ret = memcpy_from_msg(skb_put(skb, len), msg, len); 567 568 if (ret) 569 goto err; 570 ret = transmit_skb(skb, cf_sk, noblock, timeo); 571 if (ret < 0) 572 /* skb is already freed */ 573 return ret; 574 575 return len; 576err: 577 kfree_skb(skb); 578 return ret; 579} 580 581/* 582 * Copied from unix_stream_sendmsg and adapted to CAIF: 583 * Changed removed permission handling and added waiting for flow on 584 * and other minor adaptations. 585 */ 586static int caif_stream_sendmsg(struct socket *sock, struct msghdr *msg, 587 size_t len) 588{ 589 struct sock *sk = sock->sk; 590 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 591 int err, size; 592 struct sk_buff *skb; 593 int sent = 0; 594 long timeo; 595 596 err = -EOPNOTSUPP; 597 if (unlikely(msg->msg_flags&MSG_OOB)) 598 goto out_err; 599 600 if (unlikely(msg->msg_namelen)) 601 goto out_err; 602 603 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 604 timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err); 605 606 if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN)) 607 goto pipe_err; 608 609 while (sent < len) { 610 611 size = len-sent; 612 613 if (size > cf_sk->maxframe) 614 size = cf_sk->maxframe; 615 616 /* If size is more than half of sndbuf, chop up message */ 617 if (size > ((sk->sk_sndbuf >> 1) - 64)) 618 size = (sk->sk_sndbuf >> 1) - 64; 619 620 if (size > SKB_MAX_ALLOC) 621 size = SKB_MAX_ALLOC; 622 623 skb = sock_alloc_send_skb(sk, 624 size + cf_sk->headroom + 625 cf_sk->tailroom, 626 msg->msg_flags&MSG_DONTWAIT, 627 &err); 628 if (skb == NULL) 629 goto out_err; 630 631 skb_reserve(skb, cf_sk->headroom); 632 /* 633 * If you pass two values to the sock_alloc_send_skb 634 * it tries to grab the large buffer with GFP_NOFS 635 * (which can fail easily), and if it fails grab the 636 * fallback size buffer which is under a page and will 637 * succeed. [Alan] 638 */ 639 size = min_t(int, size, skb_tailroom(skb)); 640 641 err = memcpy_from_msg(skb_put(skb, size), msg, size); 642 if (err) { 643 kfree_skb(skb); 644 goto out_err; 645 } 646 err = transmit_skb(skb, cf_sk, 647 msg->msg_flags&MSG_DONTWAIT, timeo); 648 if (err < 0) 649 /* skb is already freed */ 650 goto pipe_err; 651 652 sent += size; 653 } 654 655 return sent; 656 657pipe_err: 658 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL)) 659 send_sig(SIGPIPE, current, 0); 660 err = -EPIPE; 661out_err: 662 return sent ? : err; 663} 664 665static int setsockopt(struct socket *sock, int lvl, int opt, sockptr_t ov, 666 unsigned int ol) 667{ 668 struct sock *sk = sock->sk; 669 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 670 int linksel; 671 672 if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED) 673 return -ENOPROTOOPT; 674 675 switch (opt) { 676 case CAIFSO_LINK_SELECT: 677 if (ol < sizeof(int)) 678 return -EINVAL; 679 if (lvl != SOL_CAIF) 680 goto bad_sol; 681 if (copy_from_sockptr(&linksel, ov, sizeof(int))) 682 return -EINVAL; 683 lock_sock(&(cf_sk->sk)); 684 cf_sk->conn_req.link_selector = linksel; 685 release_sock(&cf_sk->sk); 686 return 0; 687 688 case CAIFSO_REQ_PARAM: 689 if (lvl != SOL_CAIF) 690 goto bad_sol; 691 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL) 692 return -ENOPROTOOPT; 693 lock_sock(&(cf_sk->sk)); 694 if (ol > sizeof(cf_sk->conn_req.param.data) || 695 copy_from_sockptr(&cf_sk->conn_req.param.data, ov, ol)) { 696 release_sock(&cf_sk->sk); 697 return -EINVAL; 698 } 699 cf_sk->conn_req.param.size = ol; 700 release_sock(&cf_sk->sk); 701 return 0; 702 703 default: 704 return -ENOPROTOOPT; 705 } 706 707 return 0; 708bad_sol: 709 return -ENOPROTOOPT; 710 711} 712 713/* 714 * caif_connect() - Connect a CAIF Socket 715 * Copied and modified af_irda.c:irda_connect(). 716 * 717 * Note : by consulting "errno", the user space caller may learn the cause 718 * of the failure. Most of them are visible in the function, others may come 719 * from subroutines called and are listed here : 720 * o -EAFNOSUPPORT: bad socket family or type. 721 * o -ESOCKTNOSUPPORT: bad socket type or protocol 722 * o -EINVAL: bad socket address, or CAIF link type 723 * o -ECONNREFUSED: remote end refused the connection. 724 * o -EINPROGRESS: connect request sent but timed out (or non-blocking) 725 * o -EISCONN: already connected. 726 * o -ETIMEDOUT: Connection timed out (send timeout) 727 * o -ENODEV: No link layer to send request 728 * o -ECONNRESET: Received Shutdown indication or lost link layer 729 * o -ENOMEM: Out of memory 730 * 731 * State Strategy: 732 * o sk_state: holds the CAIF_* protocol state, it's updated by 733 * caif_ctrl_cb. 734 * o sock->state: holds the SS_* socket state and is updated by connect and 735 * disconnect. 736 */ 737static int caif_connect(struct socket *sock, struct sockaddr *uaddr, 738 int addr_len, int flags) 739{ 740 struct sock *sk = sock->sk; 741 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 742 long timeo; 743 int err; 744 int ifindex, headroom, tailroom; 745 unsigned int mtu; 746 struct net_device *dev; 747 748 lock_sock(sk); 749 750 err = -EINVAL; 751 if (addr_len < offsetofend(struct sockaddr, sa_family)) 752 goto out; 753 754 err = -EAFNOSUPPORT; 755 if (uaddr->sa_family != AF_CAIF) 756 goto out; 757 758 switch (sock->state) { 759 case SS_UNCONNECTED: 760 /* Normal case, a fresh connect */ 761 caif_assert(sk->sk_state == CAIF_DISCONNECTED); 762 break; 763 case SS_CONNECTING: 764 switch (sk->sk_state) { 765 case CAIF_CONNECTED: 766 sock->state = SS_CONNECTED; 767 err = -EISCONN; 768 goto out; 769 case CAIF_DISCONNECTED: 770 /* Reconnect allowed */ 771 break; 772 case CAIF_CONNECTING: 773 err = -EALREADY; 774 if (flags & O_NONBLOCK) 775 goto out; 776 goto wait_connect; 777 } 778 break; 779 case SS_CONNECTED: 780 caif_assert(sk->sk_state == CAIF_CONNECTED || 781 sk->sk_state == CAIF_DISCONNECTED); 782 if (sk->sk_shutdown & SHUTDOWN_MASK) { 783 /* Allow re-connect after SHUTDOWN_IND */ 784 caif_disconnect_client(sock_net(sk), &cf_sk->layer); 785 caif_free_client(&cf_sk->layer); 786 break; 787 } 788 /* No reconnect on a seqpacket socket */ 789 err = -EISCONN; 790 goto out; 791 case SS_DISCONNECTING: 792 case SS_FREE: 793 caif_assert(1); /*Should never happen */ 794 break; 795 } 796 sk->sk_state = CAIF_DISCONNECTED; 797 sock->state = SS_UNCONNECTED; 798 sk_stream_kill_queues(&cf_sk->sk); 799 800 err = -EINVAL; 801 if (addr_len != sizeof(struct sockaddr_caif)) 802 goto out; 803 804 memcpy(&cf_sk->conn_req.sockaddr, uaddr, 805 sizeof(struct sockaddr_caif)); 806 807 /* Move to connecting socket, start sending Connect Requests */ 808 sock->state = SS_CONNECTING; 809 sk->sk_state = CAIF_CONNECTING; 810 811 /* Check priority value comming from socket */ 812 /* if priority value is out of range it will be ajusted */ 813 if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX) 814 cf_sk->conn_req.priority = CAIF_PRIO_MAX; 815 else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN) 816 cf_sk->conn_req.priority = CAIF_PRIO_MIN; 817 else 818 cf_sk->conn_req.priority = cf_sk->sk.sk_priority; 819 820 /*ifindex = id of the interface.*/ 821 cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if; 822 823 cf_sk->layer.receive = caif_sktrecv_cb; 824 825 err = caif_connect_client(sock_net(sk), &cf_sk->conn_req, 826 &cf_sk->layer, &ifindex, &headroom, &tailroom); 827 828 if (err < 0) { 829 cf_sk->sk.sk_socket->state = SS_UNCONNECTED; 830 cf_sk->sk.sk_state = CAIF_DISCONNECTED; 831 goto out; 832 } 833 834 err = -ENODEV; 835 rcu_read_lock(); 836 dev = dev_get_by_index_rcu(sock_net(sk), ifindex); 837 if (!dev) { 838 rcu_read_unlock(); 839 goto out; 840 } 841 cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom); 842 mtu = dev->mtu; 843 rcu_read_unlock(); 844 845 cf_sk->tailroom = tailroom; 846 cf_sk->maxframe = mtu - (headroom + tailroom); 847 if (cf_sk->maxframe < 1) { 848 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu); 849 err = -ENODEV; 850 goto out; 851 } 852 853 err = -EINPROGRESS; 854wait_connect: 855 856 if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK)) 857 goto out; 858 859 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK); 860 861 release_sock(sk); 862 err = -ERESTARTSYS; 863 timeo = wait_event_interruptible_timeout(*sk_sleep(sk), 864 sk->sk_state != CAIF_CONNECTING, 865 timeo); 866 lock_sock(sk); 867 if (timeo < 0) 868 goto out; /* -ERESTARTSYS */ 869 870 err = -ETIMEDOUT; 871 if (timeo == 0 && sk->sk_state != CAIF_CONNECTED) 872 goto out; 873 if (sk->sk_state != CAIF_CONNECTED) { 874 sock->state = SS_UNCONNECTED; 875 err = sock_error(sk); 876 if (!err) 877 err = -ECONNREFUSED; 878 goto out; 879 } 880 sock->state = SS_CONNECTED; 881 err = 0; 882out: 883 release_sock(sk); 884 return err; 885} 886 887/* 888 * caif_release() - Disconnect a CAIF Socket 889 * Copied and modified af_irda.c:irda_release(). 890 */ 891static int caif_release(struct socket *sock) 892{ 893 struct sock *sk = sock->sk; 894 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 895 896 if (!sk) 897 return 0; 898 899 set_tx_flow_off(cf_sk); 900 901 /* 902 * Ensure that packets are not queued after this point in time. 903 * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock, 904 * this ensures no packets when sock is dead. 905 */ 906 spin_lock_bh(&sk->sk_receive_queue.lock); 907 sock_set_flag(sk, SOCK_DEAD); 908 spin_unlock_bh(&sk->sk_receive_queue.lock); 909 sock->sk = NULL; 910 911 WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir)); 912 debugfs_remove_recursive(cf_sk->debugfs_socket_dir); 913 914 lock_sock(&(cf_sk->sk)); 915 sk->sk_state = CAIF_DISCONNECTED; 916 sk->sk_shutdown = SHUTDOWN_MASK; 917 918 caif_disconnect_client(sock_net(sk), &cf_sk->layer); 919 cf_sk->sk.sk_socket->state = SS_DISCONNECTING; 920 wake_up_interruptible_poll(sk_sleep(sk), EPOLLERR|EPOLLHUP); 921 922 sock_orphan(sk); 923 sk_stream_kill_queues(&cf_sk->sk); 924 release_sock(sk); 925 sock_put(sk); 926 return 0; 927} 928 929/* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */ 930static __poll_t caif_poll(struct file *file, 931 struct socket *sock, poll_table *wait) 932{ 933 struct sock *sk = sock->sk; 934 __poll_t mask; 935 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 936 937 sock_poll_wait(file, sock, wait); 938 mask = 0; 939 940 /* exceptional events? */ 941 if (sk->sk_err) 942 mask |= EPOLLERR; 943 if (sk->sk_shutdown == SHUTDOWN_MASK) 944 mask |= EPOLLHUP; 945 if (sk->sk_shutdown & RCV_SHUTDOWN) 946 mask |= EPOLLRDHUP; 947 948 /* readable? */ 949 if (!skb_queue_empty_lockless(&sk->sk_receive_queue) || 950 (sk->sk_shutdown & RCV_SHUTDOWN)) 951 mask |= EPOLLIN | EPOLLRDNORM; 952 953 /* 954 * we set writable also when the other side has shut down the 955 * connection. This prevents stuck sockets. 956 */ 957 if (sock_writeable(sk) && tx_flow_is_on(cf_sk)) 958 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND; 959 960 return mask; 961} 962 963static const struct proto_ops caif_seqpacket_ops = { 964 .family = PF_CAIF, 965 .owner = THIS_MODULE, 966 .release = caif_release, 967 .bind = sock_no_bind, 968 .connect = caif_connect, 969 .socketpair = sock_no_socketpair, 970 .accept = sock_no_accept, 971 .getname = sock_no_getname, 972 .poll = caif_poll, 973 .ioctl = sock_no_ioctl, 974 .listen = sock_no_listen, 975 .shutdown = sock_no_shutdown, 976 .setsockopt = setsockopt, 977 .sendmsg = caif_seqpkt_sendmsg, 978 .recvmsg = caif_seqpkt_recvmsg, 979 .mmap = sock_no_mmap, 980}; 981 982static const struct proto_ops caif_stream_ops = { 983 .family = PF_CAIF, 984 .owner = THIS_MODULE, 985 .release = caif_release, 986 .bind = sock_no_bind, 987 .connect = caif_connect, 988 .socketpair = sock_no_socketpair, 989 .accept = sock_no_accept, 990 .getname = sock_no_getname, 991 .poll = caif_poll, 992 .ioctl = sock_no_ioctl, 993 .listen = sock_no_listen, 994 .shutdown = sock_no_shutdown, 995 .setsockopt = setsockopt, 996 .sendmsg = caif_stream_sendmsg, 997 .recvmsg = caif_stream_recvmsg, 998 .mmap = sock_no_mmap, 999}; 1000 1001/* This function is called when a socket is finally destroyed. */ 1002static void caif_sock_destructor(struct sock *sk) 1003{ 1004 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk); 1005 caif_assert(!refcount_read(&sk->sk_wmem_alloc)); 1006 caif_assert(sk_unhashed(sk)); 1007 caif_assert(!sk->sk_socket); 1008 if (!sock_flag(sk, SOCK_DEAD)) { 1009 pr_debug("Attempt to release alive CAIF socket: %p\n", sk); 1010 return; 1011 } 1012 sk_stream_kill_queues(&cf_sk->sk); 1013 WARN_ON_ONCE(sk->sk_forward_alloc); 1014 caif_free_client(&cf_sk->layer); 1015} 1016 1017static int caif_create(struct net *net, struct socket *sock, int protocol, 1018 int kern) 1019{ 1020 struct sock *sk = NULL; 1021 struct caifsock *cf_sk = NULL; 1022 static struct proto prot = {.name = "PF_CAIF", 1023 .owner = THIS_MODULE, 1024 .obj_size = sizeof(struct caifsock), 1025 .useroffset = offsetof(struct caifsock, conn_req.param), 1026 .usersize = sizeof_field(struct caifsock, conn_req.param) 1027 }; 1028 1029 if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN)) 1030 return -EPERM; 1031 /* 1032 * The sock->type specifies the socket type to use. 1033 * The CAIF socket is a packet stream in the sense 1034 * that it is packet based. CAIF trusts the reliability 1035 * of the link, no resending is implemented. 1036 */ 1037 if (sock->type == SOCK_SEQPACKET) 1038 sock->ops = &caif_seqpacket_ops; 1039 else if (sock->type == SOCK_STREAM) 1040 sock->ops = &caif_stream_ops; 1041 else 1042 return -ESOCKTNOSUPPORT; 1043 1044 if (protocol < 0 || protocol >= CAIFPROTO_MAX) 1045 return -EPROTONOSUPPORT; 1046 /* 1047 * Set the socket state to unconnected. The socket state 1048 * is really not used at all in the net/core or socket.c but the 1049 * initialization makes sure that sock->state is not uninitialized. 1050 */ 1051 sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot, kern); 1052 if (!sk) 1053 return -ENOMEM; 1054 1055 cf_sk = container_of(sk, struct caifsock, sk); 1056 1057 /* Store the protocol */ 1058 sk->sk_protocol = (unsigned char) protocol; 1059 1060 /* Initialize default priority for well-known cases */ 1061 switch (protocol) { 1062 case CAIFPROTO_AT: 1063 sk->sk_priority = TC_PRIO_CONTROL; 1064 break; 1065 case CAIFPROTO_RFM: 1066 sk->sk_priority = TC_PRIO_INTERACTIVE_BULK; 1067 break; 1068 default: 1069 sk->sk_priority = TC_PRIO_BESTEFFORT; 1070 } 1071 1072 /* 1073 * Lock in order to try to stop someone from opening the socket 1074 * too early. 1075 */ 1076 lock_sock(&(cf_sk->sk)); 1077 1078 /* Initialize the nozero default sock structure data. */ 1079 sock_init_data(sock, sk); 1080 sk->sk_destruct = caif_sock_destructor; 1081 1082 mutex_init(&cf_sk->readlock); /* single task reading lock */ 1083 cf_sk->layer.ctrlcmd = caif_ctrl_cb; 1084 cf_sk->sk.sk_socket->state = SS_UNCONNECTED; 1085 cf_sk->sk.sk_state = CAIF_DISCONNECTED; 1086 1087 set_tx_flow_off(cf_sk); 1088 set_rx_flow_on(cf_sk); 1089 1090 /* Set default options on configuration */ 1091 cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY; 1092 cf_sk->conn_req.protocol = protocol; 1093 release_sock(&cf_sk->sk); 1094 return 0; 1095} 1096 1097 1098static const struct net_proto_family caif_family_ops = { 1099 .family = PF_CAIF, 1100 .create = caif_create, 1101 .owner = THIS_MODULE, 1102}; 1103 1104static int __init caif_sktinit_module(void) 1105{ 1106 return sock_register(&caif_family_ops); 1107} 1108 1109static void __exit caif_sktexit_module(void) 1110{ 1111 sock_unregister(PF_CAIF); 1112} 1113module_init(caif_sktinit_module); 1114module_exit(caif_sktexit_module); 1115