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 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.iov->iov_base == NULL))
 543		goto err;
 544	noblock = msg->msg_flags & MSG_DONTWAIT;
 545
 546	timeo = sock_sndtimeo(sk, noblock);
 547	timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
 548				1, timeo, &ret);
 549
 550	if (ret)
 551		goto err;
 552	ret = -EPIPE;
 553	if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
 554		sock_flag(sk, SOCK_DEAD) ||
 555		(sk->sk_shutdown & RCV_SHUTDOWN))
 556		goto err;
 557
 558	/* Error if trying to write more than maximum frame size. */
 559	ret = -EMSGSIZE;
 560	if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
 561		goto err;
 562
 563	buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
 564
 565	ret = -ENOMEM;
 566	skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
 567
 568	if (!skb || skb_tailroom(skb) < buffer_size)
 569		goto err;
 570
 571	skb_reserve(skb, cf_sk->headroom);
 572
 573	ret = memcpy_from_msg(skb_put(skb, len), msg, len);
 574
 575	if (ret)
 576		goto err;
 577	ret = transmit_skb(skb, cf_sk, noblock, timeo);
 578	if (ret < 0)
 579		/* skb is already freed */
 580		return ret;
 581
 582	return len;
 583err:
 584	kfree_skb(skb);
 585	return ret;
 586}
 587
 588/*
 589 * Copied from unix_stream_sendmsg and adapted to CAIF:
 590 * Changed removed permission handling and added waiting for flow on
 591 * and other minor adaptations.
 592 */
 593static int caif_stream_sendmsg(struct socket *sock, struct msghdr *msg,
 594			       size_t len)
 595{
 596	struct sock *sk = sock->sk;
 597	struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 598	int err, size;
 599	struct sk_buff *skb;
 600	int sent = 0;
 601	long timeo;
 602
 603	err = -EOPNOTSUPP;
 604	if (unlikely(msg->msg_flags&MSG_OOB))
 605		goto out_err;
 606
 607	if (unlikely(msg->msg_namelen))
 608		goto out_err;
 609
 610	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 611	timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
 612
 613	if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
 614		goto pipe_err;
 615
 616	while (sent < len) {
 617
 618		size = len-sent;
 619
 620		if (size > cf_sk->maxframe)
 621			size = cf_sk->maxframe;
 622
 623		/* If size is more than half of sndbuf, chop up message */
 624		if (size > ((sk->sk_sndbuf >> 1) - 64))
 625			size = (sk->sk_sndbuf >> 1) - 64;
 626
 627		if (size > SKB_MAX_ALLOC)
 628			size = SKB_MAX_ALLOC;
 629
 630		skb = sock_alloc_send_skb(sk,
 631					size + cf_sk->headroom +
 632					cf_sk->tailroom,
 633					msg->msg_flags&MSG_DONTWAIT,
 634					&err);
 635		if (skb == NULL)
 636			goto out_err;
 637
 638		skb_reserve(skb, cf_sk->headroom);
 639		/*
 640		 *	If you pass two values to the sock_alloc_send_skb
 641		 *	it tries to grab the large buffer with GFP_NOFS
 642		 *	(which can fail easily), and if it fails grab the
 643		 *	fallback size buffer which is under a page and will
 644		 *	succeed. [Alan]
 645		 */
 646		size = min_t(int, size, skb_tailroom(skb));
 647
 648		err = memcpy_from_msg(skb_put(skb, size), msg, size);
 649		if (err) {
 650			kfree_skb(skb);
 651			goto out_err;
 652		}
 653		err = transmit_skb(skb, cf_sk,
 654				msg->msg_flags&MSG_DONTWAIT, timeo);
 655		if (err < 0)
 656			/* skb is already freed */
 657			goto pipe_err;
 658
 659		sent += size;
 660	}
 661
 662	return sent;
 663
 664pipe_err:
 665	if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
 666		send_sig(SIGPIPE, current, 0);
 667	err = -EPIPE;
 668out_err:
 669	return sent ? : err;
 670}
 671
 672static int setsockopt(struct socket *sock,
 673		      int lvl, int opt, char __user *ov, unsigned int ol)
 674{
 675	struct sock *sk = sock->sk;
 676	struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 677	int linksel;
 678
 679	if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
 680		return -ENOPROTOOPT;
 681
 682	switch (opt) {
 683	case CAIFSO_LINK_SELECT:
 684		if (ol < sizeof(int))
 685			return -EINVAL;
 686		if (lvl != SOL_CAIF)
 687			goto bad_sol;
 688		if (copy_from_user(&linksel, ov, sizeof(int)))
 689			return -EINVAL;
 690		lock_sock(&(cf_sk->sk));
 691		cf_sk->conn_req.link_selector = linksel;
 692		release_sock(&cf_sk->sk);
 693		return 0;
 694
 695	case CAIFSO_REQ_PARAM:
 696		if (lvl != SOL_CAIF)
 697			goto bad_sol;
 698		if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
 699			return -ENOPROTOOPT;
 700		lock_sock(&(cf_sk->sk));
 701		if (ol > sizeof(cf_sk->conn_req.param.data) ||
 702			copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
 703			release_sock(&cf_sk->sk);
 704			return -EINVAL;
 705		}
 706		cf_sk->conn_req.param.size = ol;
 707		release_sock(&cf_sk->sk);
 708		return 0;
 709
 710	default:
 711		return -ENOPROTOOPT;
 712	}
 713
 714	return 0;
 715bad_sol:
 716	return -ENOPROTOOPT;
 717
 718}
 719
 720/*
 721 * caif_connect() - Connect a CAIF Socket
 722 * Copied and modified af_irda.c:irda_connect().
 723 *
 724 * Note : by consulting "errno", the user space caller may learn the cause
 725 * of the failure. Most of them are visible in the function, others may come
 726 * from subroutines called and are listed here :
 727 *  o -EAFNOSUPPORT: bad socket family or type.
 728 *  o -ESOCKTNOSUPPORT: bad socket type or protocol
 729 *  o -EINVAL: bad socket address, or CAIF link type
 730 *  o -ECONNREFUSED: remote end refused the connection.
 731 *  o -EINPROGRESS: connect request sent but timed out (or non-blocking)
 732 *  o -EISCONN: already connected.
 733 *  o -ETIMEDOUT: Connection timed out (send timeout)
 734 *  o -ENODEV: No link layer to send request
 735 *  o -ECONNRESET: Received Shutdown indication or lost link layer
 736 *  o -ENOMEM: Out of memory
 737 *
 738 *  State Strategy:
 739 *  o sk_state: holds the CAIF_* protocol state, it's updated by
 740 *	caif_ctrl_cb.
 741 *  o sock->state: holds the SS_* socket state and is updated by connect and
 742 *	disconnect.
 743 */
 744static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
 745			int addr_len, int flags)
 746{
 747	struct sock *sk = sock->sk;
 748	struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 749	long timeo;
 750	int err;
 751	int ifindex, headroom, tailroom;
 752	unsigned int mtu;
 753	struct net_device *dev;
 754
 755	lock_sock(sk);
 756
 757	err = -EAFNOSUPPORT;
 758	if (uaddr->sa_family != AF_CAIF)
 759		goto out;
 760
 761	switch (sock->state) {
 762	case SS_UNCONNECTED:
 763		/* Normal case, a fresh connect */
 764		caif_assert(sk->sk_state == CAIF_DISCONNECTED);
 765		break;
 766	case SS_CONNECTING:
 767		switch (sk->sk_state) {
 768		case CAIF_CONNECTED:
 769			sock->state = SS_CONNECTED;
 770			err = -EISCONN;
 771			goto out;
 772		case CAIF_DISCONNECTED:
 773			/* Reconnect allowed */
 774			break;
 775		case CAIF_CONNECTING:
 776			err = -EALREADY;
 777			if (flags & O_NONBLOCK)
 778				goto out;
 779			goto wait_connect;
 780		}
 781		break;
 782	case SS_CONNECTED:
 783		caif_assert(sk->sk_state == CAIF_CONNECTED ||
 784				sk->sk_state == CAIF_DISCONNECTED);
 785		if (sk->sk_shutdown & SHUTDOWN_MASK) {
 786			/* Allow re-connect after SHUTDOWN_IND */
 787			caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 788			caif_free_client(&cf_sk->layer);
 789			break;
 790		}
 791		/* No reconnect on a seqpacket socket */
 792		err = -EISCONN;
 793		goto out;
 794	case SS_DISCONNECTING:
 795	case SS_FREE:
 796		caif_assert(1); /*Should never happen */
 797		break;
 798	}
 799	sk->sk_state = CAIF_DISCONNECTED;
 800	sock->state = SS_UNCONNECTED;
 801	sk_stream_kill_queues(&cf_sk->sk);
 802
 803	err = -EINVAL;
 804	if (addr_len != sizeof(struct sockaddr_caif))
 805		goto out;
 806
 807	memcpy(&cf_sk->conn_req.sockaddr, uaddr,
 808		sizeof(struct sockaddr_caif));
 809
 810	/* Move to connecting socket, start sending Connect Requests */
 811	sock->state = SS_CONNECTING;
 812	sk->sk_state = CAIF_CONNECTING;
 813
 814	/* Check priority value comming from socket */
 815	/* if priority value is out of range it will be ajusted */
 816	if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
 817		cf_sk->conn_req.priority = CAIF_PRIO_MAX;
 818	else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
 819		cf_sk->conn_req.priority = CAIF_PRIO_MIN;
 820	else
 821		cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
 822
 823	/*ifindex = id of the interface.*/
 824	cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
 825
 826	cf_sk->layer.receive = caif_sktrecv_cb;
 827
 828	err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
 829				&cf_sk->layer, &ifindex, &headroom, &tailroom);
 830
 831	if (err < 0) {
 832		cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
 833		cf_sk->sk.sk_state = CAIF_DISCONNECTED;
 834		goto out;
 835	}
 836
 837	err = -ENODEV;
 838	rcu_read_lock();
 839	dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
 840	if (!dev) {
 841		rcu_read_unlock();
 842		goto out;
 843	}
 844	cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
 845	mtu = dev->mtu;
 846	rcu_read_unlock();
 847
 848	cf_sk->tailroom = tailroom;
 849	cf_sk->maxframe = mtu - (headroom + tailroom);
 850	if (cf_sk->maxframe < 1) {
 851		pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
 852		err = -ENODEV;
 853		goto out;
 854	}
 855
 856	err = -EINPROGRESS;
 857wait_connect:
 858
 859	if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
 860		goto out;
 861
 862	timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
 863
 864	release_sock(sk);
 865	err = -ERESTARTSYS;
 866	timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
 867			sk->sk_state != CAIF_CONNECTING,
 868			timeo);
 869	lock_sock(sk);
 870	if (timeo < 0)
 871		goto out; /* -ERESTARTSYS */
 872
 873	err = -ETIMEDOUT;
 874	if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
 875		goto out;
 876	if (sk->sk_state != CAIF_CONNECTED) {
 877		sock->state = SS_UNCONNECTED;
 878		err = sock_error(sk);
 879		if (!err)
 880			err = -ECONNREFUSED;
 881		goto out;
 882	}
 883	sock->state = SS_CONNECTED;
 884	err = 0;
 885out:
 886	release_sock(sk);
 887	return err;
 888}
 889
 890/*
 891 * caif_release() - Disconnect a CAIF Socket
 892 * Copied and modified af_irda.c:irda_release().
 893 */
 894static int caif_release(struct socket *sock)
 895{
 896	struct sock *sk = sock->sk;
 897	struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 898
 899	if (!sk)
 900		return 0;
 901
 902	set_tx_flow_off(cf_sk);
 903
 904	/*
 905	 * Ensure that packets are not queued after this point in time.
 906	 * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
 907	 * this ensures no packets when sock is dead.
 908	 */
 909	spin_lock_bh(&sk->sk_receive_queue.lock);
 910	sock_set_flag(sk, SOCK_DEAD);
 911	spin_unlock_bh(&sk->sk_receive_queue.lock);
 912	sock->sk = NULL;
 913
 914	WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
 915	debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
 
 916
 917	lock_sock(&(cf_sk->sk));
 918	sk->sk_state = CAIF_DISCONNECTED;
 919	sk->sk_shutdown = SHUTDOWN_MASK;
 920
 921	caif_disconnect_client(sock_net(sk), &cf_sk->layer);
 922	cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
 923	wake_up_interruptible_poll(sk_sleep(sk), POLLERR|POLLHUP);
 924
 925	sock_orphan(sk);
 926	sk_stream_kill_queues(&cf_sk->sk);
 927	release_sock(sk);
 928	sock_put(sk);
 929	return 0;
 930}
 931
 932/* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
 933static unsigned int caif_poll(struct file *file,
 934			      struct socket *sock, poll_table *wait)
 935{
 936	struct sock *sk = sock->sk;
 937	unsigned int mask;
 938	struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
 939
 940	sock_poll_wait(file, sk_sleep(sk), wait);
 941	mask = 0;
 942
 943	/* exceptional events? */
 944	if (sk->sk_err)
 945		mask |= POLLERR;
 946	if (sk->sk_shutdown == SHUTDOWN_MASK)
 947		mask |= POLLHUP;
 948	if (sk->sk_shutdown & RCV_SHUTDOWN)
 949		mask |= POLLRDHUP;
 950
 951	/* readable? */
 952	if (!skb_queue_empty(&sk->sk_receive_queue) ||
 953		(sk->sk_shutdown & RCV_SHUTDOWN))
 954		mask |= POLLIN | POLLRDNORM;
 955
 956	/*
 957	 * we set writable also when the other side has shut down the
 958	 * connection. This prevents stuck sockets.
 959	 */
 960	if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
 961		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
 962
 963	return mask;
 964}
 965
 966static const struct proto_ops caif_seqpacket_ops = {
 967	.family = PF_CAIF,
 968	.owner = THIS_MODULE,
 969	.release = caif_release,
 970	.bind = sock_no_bind,
 971	.connect = caif_connect,
 972	.socketpair = sock_no_socketpair,
 973	.accept = sock_no_accept,
 974	.getname = sock_no_getname,
 975	.poll = caif_poll,
 976	.ioctl = sock_no_ioctl,
 977	.listen = sock_no_listen,
 978	.shutdown = sock_no_shutdown,
 979	.setsockopt = setsockopt,
 980	.getsockopt = sock_no_getsockopt,
 981	.sendmsg = caif_seqpkt_sendmsg,
 982	.recvmsg = caif_seqpkt_recvmsg,
 983	.mmap = sock_no_mmap,
 984	.sendpage = sock_no_sendpage,
 985};
 986
 987static const struct proto_ops caif_stream_ops = {
 988	.family = PF_CAIF,
 989	.owner = THIS_MODULE,
 990	.release = caif_release,
 991	.bind = sock_no_bind,
 992	.connect = caif_connect,
 993	.socketpair = sock_no_socketpair,
 994	.accept = sock_no_accept,
 995	.getname = sock_no_getname,
 996	.poll = caif_poll,
 997	.ioctl = sock_no_ioctl,
 998	.listen = sock_no_listen,
 999	.shutdown = sock_no_shutdown,
1000	.setsockopt = setsockopt,
1001	.getsockopt = sock_no_getsockopt,
1002	.sendmsg = caif_stream_sendmsg,
1003	.recvmsg = caif_stream_recvmsg,
1004	.mmap = sock_no_mmap,
1005	.sendpage = sock_no_sendpage,
1006};
1007
1008/* This function is called when a socket is finally destroyed. */
1009static void caif_sock_destructor(struct sock *sk)
1010{
1011	struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1012	caif_assert(!atomic_read(&sk->sk_wmem_alloc));
1013	caif_assert(sk_unhashed(sk));
1014	caif_assert(!sk->sk_socket);
1015	if (!sock_flag(sk, SOCK_DEAD)) {
1016		pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
1017		return;
1018	}
1019	sk_stream_kill_queues(&cf_sk->sk);
1020	caif_free_client(&cf_sk->layer);
1021}
1022
1023static int caif_create(struct net *net, struct socket *sock, int protocol,
1024		       int kern)
1025{
1026	struct sock *sk = NULL;
1027	struct caifsock *cf_sk = NULL;
1028	static struct proto prot = {.name = "PF_CAIF",
1029		.owner = THIS_MODULE,
1030		.obj_size = sizeof(struct caifsock),
1031	};
1032
1033	if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1034		return -EPERM;
1035	/*
1036	 * The sock->type specifies the socket type to use.
1037	 * The CAIF socket is a packet stream in the sense
1038	 * that it is packet based. CAIF trusts the reliability
1039	 * of the link, no resending is implemented.
1040	 */
1041	if (sock->type == SOCK_SEQPACKET)
1042		sock->ops = &caif_seqpacket_ops;
1043	else if (sock->type == SOCK_STREAM)
1044		sock->ops = &caif_stream_ops;
1045	else
1046		return -ESOCKTNOSUPPORT;
1047
1048	if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1049		return -EPROTONOSUPPORT;
1050	/*
1051	 * Set the socket state to unconnected.	 The socket state
1052	 * is really not used at all in the net/core or socket.c but the
1053	 * initialization makes sure that sock->state is not uninitialized.
1054	 */
1055	sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot, kern);
1056	if (!sk)
1057		return -ENOMEM;
1058
1059	cf_sk = container_of(sk, struct caifsock, sk);
1060
1061	/* Store the protocol */
1062	sk->sk_protocol = (unsigned char) protocol;
1063
1064	/* Initialize default priority for well-known cases */
1065	switch (protocol) {
1066	case CAIFPROTO_AT:
1067		sk->sk_priority = TC_PRIO_CONTROL;
1068		break;
1069	case CAIFPROTO_RFM:
1070		sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
1071		break;
1072	default:
1073		sk->sk_priority = TC_PRIO_BESTEFFORT;
1074	}
1075
1076	/*
1077	 * Lock in order to try to stop someone from opening the socket
1078	 * too early.
1079	 */
1080	lock_sock(&(cf_sk->sk));
1081
1082	/* Initialize the nozero default sock structure data. */
1083	sock_init_data(sock, sk);
1084	sk->sk_destruct = caif_sock_destructor;
1085
1086	mutex_init(&cf_sk->readlock); /* single task reading lock */
1087	cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1088	cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1089	cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1090
1091	set_tx_flow_off(cf_sk);
1092	set_rx_flow_on(cf_sk);
1093
1094	/* Set default options on configuration */
1095	cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1096	cf_sk->conn_req.protocol = protocol;
1097	release_sock(&cf_sk->sk);
1098	return 0;
1099}
1100
1101
1102static struct net_proto_family caif_family_ops = {
1103	.family = PF_CAIF,
1104	.create = caif_create,
1105	.owner = THIS_MODULE,
1106};
1107
1108static int __init caif_sktinit_module(void)
1109{
1110	int err = sock_register(&caif_family_ops);
1111	if (!err)
1112		return err;
1113	return 0;
1114}
1115
1116static void __exit caif_sktexit_module(void)
1117{
1118	sock_unregister(PF_CAIF);
1119}
1120module_init(caif_sktinit_module);
1121module_exit(caif_sktexit_module);