net-caif: add CAIF socket implementation

Implementation of CAIF sockets for protocol and address family
PF_CAIF and AF_CAIF.
CAIF socket is connection oriented implementing SOCK_SEQPACKET
and SOCK_STREAM interface with supporting blocking and non-blocking mode.

Signed-off-by: Sjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/caif/caif_socket.c

@@ -0,0 +1,1391 @@
+/*
+ * Copyright (C) ST-Ericsson AB 2010
+ * Author:	Sjur Brendeland sjur.brandeland@stericsson.com
+ *		Per Sigmond per.sigmond@stericsson.com
+ * License terms: GNU General Public License (GPL) version 2
+ */
+
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/list.h>
+#include <linux/wait.h>
+#include <linux/poll.h>
+#include <linux/tcp.h>
+#include <linux/uaccess.h>
+#include <asm/atomic.h>
+
+#include <linux/caif/caif_socket.h>
+#include <net/caif/caif_layer.h>
+#include <net/caif/caif_dev.h>
+#include <net/caif/cfpkt.h>
+
+MODULE_LICENSE("GPL");
+
+#define CHNL_SKT_READ_QUEUE_HIGH 200
+#define CHNL_SKT_READ_QUEUE_LOW 100
+
+static int caif_sockbuf_size = 40000;
+static atomic_t caif_nr_socks = ATOMIC_INIT(0);
+
+#define CONN_STATE_OPEN_BIT	      1
+#define CONN_STATE_PENDING_BIT	      2
+#define CONN_STATE_PEND_DESTROY_BIT   3
+#define CONN_REMOTE_SHUTDOWN_BIT      4
+
+#define TX_FLOW_ON_BIT		      1
+#define RX_FLOW_ON_BIT		      2
+
+#define STATE_IS_OPEN(cf_sk) test_bit(CONN_STATE_OPEN_BIT,\
+				    (void *) &(cf_sk)->conn_state)
+#define STATE_IS_REMOTE_SHUTDOWN(cf_sk) test_bit(CONN_REMOTE_SHUTDOWN_BIT,\
+				    (void *) &(cf_sk)->conn_state)
+#define STATE_IS_PENDING(cf_sk) test_bit(CONN_STATE_PENDING_BIT,\
+				       (void *) &(cf_sk)->conn_state)
+#define STATE_IS_PENDING_DESTROY(cf_sk) test_bit(CONN_STATE_PEND_DESTROY_BIT,\
+				       (void *) &(cf_sk)->conn_state)
+
+#define SET_STATE_PENDING_DESTROY(cf_sk) set_bit(CONN_STATE_PEND_DESTROY_BIT,\
+				    (void *) &(cf_sk)->conn_state)
+#define SET_STATE_OPEN(cf_sk) set_bit(CONN_STATE_OPEN_BIT,\
+				    (void *) &(cf_sk)->conn_state)
+#define SET_STATE_CLOSED(cf_sk) clear_bit(CONN_STATE_OPEN_BIT,\
+					(void *) &(cf_sk)->conn_state)
+#define SET_PENDING_ON(cf_sk) set_bit(CONN_STATE_PENDING_BIT,\
+				    (void *) &(cf_sk)->conn_state)
+#define SET_PENDING_OFF(cf_sk) clear_bit(CONN_STATE_PENDING_BIT,\
+				       (void *) &(cf_sk)->conn_state)
+#define SET_REMOTE_SHUTDOWN(cf_sk) set_bit(CONN_REMOTE_SHUTDOWN_BIT,\
+				    (void *) &(cf_sk)->conn_state)
+
+#define SET_REMOTE_SHUTDOWN_OFF(dev) clear_bit(CONN_REMOTE_SHUTDOWN_BIT,\
+				    (void *) &(dev)->conn_state)
+#define RX_FLOW_IS_ON(cf_sk) test_bit(RX_FLOW_ON_BIT,\
+				    (void *) &(cf_sk)->flow_state)
+#define TX_FLOW_IS_ON(cf_sk) test_bit(TX_FLOW_ON_BIT,\
+				    (void *) &(cf_sk)->flow_state)
+
+#define SET_RX_FLOW_OFF(cf_sk) clear_bit(RX_FLOW_ON_BIT,\
+				       (void *) &(cf_sk)->flow_state)
+#define SET_RX_FLOW_ON(cf_sk) set_bit(RX_FLOW_ON_BIT,\
+				    (void *) &(cf_sk)->flow_state)
+#define SET_TX_FLOW_OFF(cf_sk) clear_bit(TX_FLOW_ON_BIT,\
+				       (void *) &(cf_sk)->flow_state)
+#define SET_TX_FLOW_ON(cf_sk) set_bit(TX_FLOW_ON_BIT,\
+				    (void *) &(cf_sk)->flow_state)
+
+#define SKT_READ_FLAG 0x01
+#define SKT_WRITE_FLAG 0x02
+static struct dentry *debugfsdir;
+#include <linux/debugfs.h>
+
+#ifdef CONFIG_DEBUG_FS
+struct debug_fs_counter {
+	atomic_t num_open;
+	atomic_t num_close;
+	atomic_t num_init;
+	atomic_t num_init_resp;
+	atomic_t num_init_fail_resp;
+	atomic_t num_deinit;
+	atomic_t num_deinit_resp;
+	atomic_t num_remote_shutdown_ind;
+	atomic_t num_tx_flow_off_ind;
+	atomic_t num_tx_flow_on_ind;
+	atomic_t num_rx_flow_off;
+	atomic_t num_rx_flow_on;
+	atomic_t skb_in_use;
+	atomic_t skb_alloc;
+	atomic_t skb_free;
+};
+static struct debug_fs_counter cnt;
+#define	dbfs_atomic_inc(v) atomic_inc(v)
+#define	dbfs_atomic_dec(v) atomic_dec(v)
+#else
+#define	dbfs_atomic_inc(v)
+#define	dbfs_atomic_dec(v)
+#endif
+
+/* The AF_CAIF socket */
+struct caifsock {
+	/* NOTE: sk has to be the first member */
+	struct sock sk;
+	struct cflayer layer;
+	char name[CAIF_LAYER_NAME_SZ];
+	u32 conn_state;
+	u32 flow_state;
+	struct cfpktq *pktq;
+	int file_mode;
+	struct caif_connect_request conn_req;
+	int read_queue_len;
+	/* protect updates of read_queue_len */
+	spinlock_t read_queue_len_lock;
+	struct dentry *debugfs_socket_dir;
+};
+
+static void drain_queue(struct caifsock *cf_sk);
+
+/* Packet Receive Callback function called from CAIF Stack */
+static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
+{
+	struct caifsock *cf_sk;
+	int read_queue_high;
+	cf_sk = container_of(layr, struct caifsock, layer);
+
+	if (!STATE_IS_OPEN(cf_sk)) {
+		/*FIXME: This should be allowed finally!*/
+		pr_debug("CAIF: %s(): called after close request\n", __func__);
+		cfpkt_destroy(pkt);
+		return 0;
+	}
+	/* NOTE: This function may be called in Tasklet context! */
+
+	/* The queue has its own lock */
+	cfpkt_queue(cf_sk->pktq, pkt, 0);
+
+	spin_lock(&cf_sk->read_queue_len_lock);
+	cf_sk->read_queue_len++;
+
+	read_queue_high = (cf_sk->read_queue_len > CHNL_SKT_READ_QUEUE_HIGH);
+	spin_unlock(&cf_sk->read_queue_len_lock);
+
+	if (RX_FLOW_IS_ON(cf_sk) && read_queue_high) {
+		dbfs_atomic_inc(&cnt.num_rx_flow_off);
+		SET_RX_FLOW_OFF(cf_sk);
+
+		/* Send flow off (NOTE: must not sleep) */
+		pr_debug("CAIF: %s():"
+			" sending flow OFF (queue len = %d)\n",
+			__func__,
+		     cf_sk->read_queue_len);
+		caif_assert(cf_sk->layer.dn);
+		caif_assert(cf_sk->layer.dn->ctrlcmd);
+
+		(void) cf_sk->layer.dn->modemcmd(cf_sk->layer.dn,
+					       CAIF_MODEMCMD_FLOW_OFF_REQ);
+	}
+
+	/* Signal reader that data is available. */
+
+	wake_up_interruptible(cf_sk->sk.sk_sleep);
+
+	return 0;
+}
+
+/* Packet Flow Control Callback function called from CAIF */
+static void caif_sktflowctrl_cb(struct cflayer *layr,
+				enum caif_ctrlcmd flow,
+				int phyid)
+{
+	struct caifsock *cf_sk;
+
+	/* NOTE: This function may be called in Tasklet context! */
+	pr_debug("CAIF: %s(): flowctrl func called: %s.\n",
+		      __func__,
+		      flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
+		      flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
+		      flow == CAIF_CTRLCMD_INIT_RSP ? "INIT_RSP" :
+		      flow == CAIF_CTRLCMD_DEINIT_RSP ? "DEINIT_RSP" :
+		      flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "INIT_FAIL_RSP" :
+		      flow ==
+		      CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ? "REMOTE_SHUTDOWN" :
+		      "UKNOWN CTRL COMMAND");
+
+	if (layr == NULL)
+		return;
+
+	cf_sk = container_of(layr, struct caifsock, layer);
+
+	switch (flow) {
+	case CAIF_CTRLCMD_FLOW_ON_IND:
+		dbfs_atomic_inc(&cnt.num_tx_flow_on_ind);
+		/* Signal reader that data is available. */
+		SET_TX_FLOW_ON(cf_sk);
+		wake_up_interruptible(cf_sk->sk.sk_sleep);
+		break;
+
+	case CAIF_CTRLCMD_FLOW_OFF_IND:
+		dbfs_atomic_inc(&cnt.num_tx_flow_off_ind);
+		SET_TX_FLOW_OFF(cf_sk);
+		break;
+
+	case CAIF_CTRLCMD_INIT_RSP:
+		dbfs_atomic_inc(&cnt.num_init_resp);
+		/* Signal reader that data is available. */
+		caif_assert(STATE_IS_OPEN(cf_sk));
+		SET_PENDING_OFF(cf_sk);
+		SET_TX_FLOW_ON(cf_sk);
+		wake_up_interruptible(cf_sk->sk.sk_sleep);
+		break;
+
+	case CAIF_CTRLCMD_DEINIT_RSP:
+		dbfs_atomic_inc(&cnt.num_deinit_resp);
+		caif_assert(!STATE_IS_OPEN(cf_sk));
+		SET_PENDING_OFF(cf_sk);
+		if (!STATE_IS_PENDING_DESTROY(cf_sk)) {
+			if (cf_sk->sk.sk_sleep != NULL)
+				wake_up_interruptible(cf_sk->sk.sk_sleep);
+		}
+		dbfs_atomic_inc(&cnt.num_deinit);
+		sock_put(&cf_sk->sk);
+		break;
+
+	case CAIF_CTRLCMD_INIT_FAIL_RSP:
+		dbfs_atomic_inc(&cnt.num_init_fail_resp);
+		caif_assert(STATE_IS_OPEN(cf_sk));
+		SET_STATE_CLOSED(cf_sk);
+		SET_PENDING_OFF(cf_sk);
+		SET_TX_FLOW_OFF(cf_sk);
+		wake_up_interruptible(cf_sk->sk.sk_sleep);
+		break;
+
+	case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
+		dbfs_atomic_inc(&cnt.num_remote_shutdown_ind);
+		SET_REMOTE_SHUTDOWN(cf_sk);
+		/* Use sk_shutdown to indicate remote shutdown indication */
+		cf_sk->sk.sk_shutdown |= RCV_SHUTDOWN;
+		cf_sk->file_mode = 0;
+		wake_up_interruptible(cf_sk->sk.sk_sleep);
+		break;
+
+	default:
+		pr_debug("CAIF: %s(): Unexpected flow command %d\n",
+			      __func__, flow);
+	}
+}
+
+static void skb_destructor(struct sk_buff *skb)
+{
+	dbfs_atomic_inc(&cnt.skb_free);
+	dbfs_atomic_dec(&cnt.skb_in_use);
+}
+
+
+static int caif_recvmsg(struct kiocb *iocb, struct socket *sock,
+				struct msghdr *m, size_t buf_len, int flags)
+
+{
+	struct sock *sk = sock->sk;
+	struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
+	struct cfpkt *pkt = NULL;
+	size_t len;
+	int result;
+	struct sk_buff *skb;
+	ssize_t ret = -EIO;
+	int read_queue_low;
+
+	if (cf_sk == NULL) {
+		pr_debug("CAIF: %s(): private_data not set!\n",
+			      __func__);
+		ret = -EBADFD;
+		goto read_error;
+	}
+
+	/* Don't do multiple iovec entries yet */
+	if (m->msg_iovlen != 1)
+		return -EOPNOTSUPP;
+
+	if (unlikely(!buf_len))
+		return -EINVAL;
+
+	lock_sock(&(cf_sk->sk));
+
+	caif_assert(cf_sk->pktq);
+
+	if (!STATE_IS_OPEN(cf_sk)) {
+		/* Socket is closed or closing. */
+		if (!STATE_IS_PENDING(cf_sk)) {
+			pr_debug("CAIF: %s(): socket is closed (by remote)\n",
+				 __func__);
+			ret = -EPIPE;
+		} else {
+			pr_debug("CAIF: %s(): socket is closing..\n", __func__);
+			ret = -EBADF;
+		}
+		goto read_error;
+	}
+	/* Socket is open or opening. */
+	if (STATE_IS_PENDING(cf_sk)) {
+		pr_debug("CAIF: %s(): socket is opening...\n", __func__);
+
+		if (flags & MSG_DONTWAIT) {
+			/* We can't block. */
+			pr_debug("CAIF: %s():state pending and MSG_DONTWAIT\n",
+				 __func__);
+			ret = -EAGAIN;
+			goto read_error;
+		}
+
+		/*
+		 * Blocking mode; state is pending and we need to wait
+		 * for its conclusion.
+		 */
+		release_sock(&cf_sk->sk);
+
+		result =
+		    wait_event_interruptible(*cf_sk->sk.sk_sleep,
+					     !STATE_IS_PENDING(cf_sk));
+
+		lock_sock(&(cf_sk->sk));
+
+		if (result == -ERESTARTSYS) {
+			pr_debug("CAIF: %s(): wait_event_interruptible"
+				 " woken by a signal (1)", __func__);
+			ret = -ERESTARTSYS;
+			goto read_error;
+		}
+	}
+
+	if (STATE_IS_REMOTE_SHUTDOWN(cf_sk) ||
+		!STATE_IS_OPEN(cf_sk) ||
+		STATE_IS_PENDING(cf_sk)) {
+
+		pr_debug("CAIF: %s(): socket closed\n",
+			__func__);
+		ret = -ESHUTDOWN;
+		goto read_error;
+	}
+
+	/*
+	 * Block if we don't have any received buffers.
+	 * The queue has its own lock.
+	 */
+	while ((pkt = cfpkt_qpeek(cf_sk->pktq)) == NULL) {
+
+		if (flags & MSG_DONTWAIT) {
+			pr_debug("CAIF: %s(): MSG_DONTWAIT\n", __func__);
+			ret = -EAGAIN;
+			goto read_error;
+		}
+		trace_printk("CAIF: %s() wait_event\n", __func__);
+
+		/* Let writers in. */
+		release_sock(&cf_sk->sk);
+
+		/* Block reader until data arrives or socket is closed. */
+		if (wait_event_interruptible(*cf_sk->sk.sk_sleep,
+					cfpkt_qpeek(cf_sk->pktq)
+					|| STATE_IS_REMOTE_SHUTDOWN(cf_sk)
+					|| !STATE_IS_OPEN(cf_sk)) ==
+		    -ERESTARTSYS) {
+			pr_debug("CAIF: %s():"
+				" wait_event_interruptible woken by "
+				"a signal, signal_pending(current) = %d\n",
+				__func__,
+				signal_pending(current));
+			return -ERESTARTSYS;
+		}
+
+		trace_printk("CAIF: %s() awake\n", __func__);
+		if (STATE_IS_REMOTE_SHUTDOWN(cf_sk)) {
+			pr_debug("CAIF: %s(): "
+				 "received remote_shutdown indication\n",
+				 __func__);
+			ret = -ESHUTDOWN;
+			goto read_error_no_unlock;
+		}
+
+		/* I want to be alone on cf_sk (except status and queue). */
+		lock_sock(&(cf_sk->sk));
+
+		if (!STATE_IS_OPEN(cf_sk)) {
+			/* Someone closed the link, report error. */
+			pr_debug("CAIF: %s(): remote end shutdown!\n",
+				      __func__);
+			ret = -EPIPE;
+			goto read_error;
+		}
+	}
+
+	/* The queue has its own lock. */
+	len = cfpkt_getlen(pkt);
+
+	/* Check max length that can be copied. */
+	if (len <= buf_len)
+		pkt = cfpkt_dequeue(cf_sk->pktq);
+	else {
+		pr_debug("CAIF: %s(): user buffer too small (%ld,%ld)\n",
+			 __func__, (long) len, (long) buf_len);
+		if (sock->type == SOCK_SEQPACKET) {
+			ret = -EMSGSIZE;
+			goto read_error;
+		}
+		len = buf_len;
+	}
+
+
+	spin_lock(&cf_sk->read_queue_len_lock);
+	cf_sk->read_queue_len--;
+	read_queue_low = (cf_sk->read_queue_len < CHNL_SKT_READ_QUEUE_LOW);
+	spin_unlock(&cf_sk->read_queue_len_lock);
+
+	if (!RX_FLOW_IS_ON(cf_sk) && read_queue_low) {
+		dbfs_atomic_inc(&cnt.num_rx_flow_on);
+		SET_RX_FLOW_ON(cf_sk);
+
+		/* Send flow on. */
+		pr_debug("CAIF: %s(): sending flow ON (queue len = %d)\n",
+			 __func__, cf_sk->read_queue_len);
+		caif_assert(cf_sk->layer.dn);
+		caif_assert(cf_sk->layer.dn->ctrlcmd);
+		(void) cf_sk->layer.dn->modemcmd(cf_sk->layer.dn,
+					       CAIF_MODEMCMD_FLOW_ON_REQ);
+
+		caif_assert(cf_sk->read_queue_len >= 0);
+	}
+
+	skb = cfpkt_tonative(pkt);
+	result = skb_copy_datagram_iovec(skb, 0, m->msg_iov, len);
+	skb_pull(skb, len);
+
+	if (result) {
+		pr_debug("CAIF: %s(): copy to_iovec failed\n", __func__);
+		cfpkt_destroy(pkt);
+		ret = -EFAULT;
+		goto read_error;
+	}
+
+	/* Free packet and remove from queue */
+	if (skb->len == 0)
+		skb_free_datagram(sk, skb);
+
+	/* Let the others in. */
+	release_sock(&cf_sk->sk);
+	return len;
+
+read_error:
+	release_sock(&cf_sk->sk);
+read_error_no_unlock:
+	return ret;
+}
+
+/* Send a signal as a consequence of sendmsg, sendto or caif_sendmsg. */
+static int caif_sendmsg(struct kiocb *kiocb, struct socket *sock,
+			struct msghdr *msg, size_t len)
+{
+
+	struct sock *sk = sock->sk;
+	struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
+	size_t payload_size = msg->msg_iov->iov_len;
+	struct cfpkt *pkt = NULL;
+	struct caif_payload_info info;
+	unsigned char *txbuf;
+	ssize_t ret = -EIO;
+	int result;
+	struct sk_buff *skb;
+	caif_assert(msg->msg_iovlen == 1);
+
+	if (cf_sk == NULL) {
+		pr_debug("CAIF: %s(): private_data not set!\n",
+			      __func__);
+		ret = -EBADFD;
+		goto write_error_no_unlock;
+	}
+
+	if (unlikely(msg->msg_iov->iov_base == NULL)) {
+		pr_warning("CAIF: %s(): Buffer is NULL.\n", __func__);
+		ret = -EINVAL;
+		goto write_error_no_unlock;
+	}
+
+	if (payload_size > CAIF_MAX_PAYLOAD_SIZE) {
+		pr_debug("CAIF: %s(): buffer too long\n", __func__);
+		if (sock->type == SOCK_SEQPACKET) {
+			ret = -EINVAL;
+			goto write_error_no_unlock;
+		}
+		payload_size = CAIF_MAX_PAYLOAD_SIZE;
+	}
+
+	/* I want to be alone on cf_sk (except status and queue) */
+	lock_sock(&(cf_sk->sk));
+
+	caif_assert(cf_sk->pktq);
+
+	if (!STATE_IS_OPEN(cf_sk)) {
+		/* Socket is closed or closing */
+		if (!STATE_IS_PENDING(cf_sk)) {
+			pr_debug("CAIF: %s(): socket is closed (by remote)\n",
+				 __func__);
+			ret = -EPIPE;
+		} else {
+			pr_debug("CAIF: %s(): socket is closing...\n",
+				 __func__);
+			ret = -EBADF;
+		}
+		goto write_error;
+	}
+
+	/* Socket is open or opening */
+	if (STATE_IS_PENDING(cf_sk)) {
+		pr_debug("CAIF: %s(): socket is opening...\n", __func__);
+
+		if (msg->msg_flags & MSG_DONTWAIT) {
+			/* We can't block */
+			trace_printk("CAIF: %s():state pending:"
+				     "state=MSG_DONTWAIT\n", __func__);
+			ret = -EAGAIN;
+			goto write_error;
+		}
+		/* Let readers in */
+		release_sock(&cf_sk->sk);
+
+		/*
+		 * Blocking mode; state is pending and we need to wait
+		 * for its conclusion.
+		 */
+		result =
+		    wait_event_interruptible(*cf_sk->sk.sk_sleep,
+					     !STATE_IS_PENDING(cf_sk));
+		/* I want to be alone on cf_sk (except status and queue) */
+		lock_sock(&(cf_sk->sk));
+
+		if (result == -ERESTARTSYS) {
+			pr_debug("CAIF: %s(): wait_event_interruptible"
+				 " woken by a signal (1)", __func__);
+			ret = -ERESTARTSYS;
+			goto write_error;
+		}
+	}
+	if (STATE_IS_REMOTE_SHUTDOWN(cf_sk) ||
+		!STATE_IS_OPEN(cf_sk) ||
+		STATE_IS_PENDING(cf_sk)) {
+
+		pr_debug("CAIF: %s(): socket closed\n",
+			__func__);
+		ret = -ESHUTDOWN;
+		goto write_error;
+	}
+
+	if (!TX_FLOW_IS_ON(cf_sk)) {
+
+		/* Flow is off. Check non-block flag */
+		if (msg->msg_flags & MSG_DONTWAIT) {
+			trace_printk("CAIF: %s(): MSG_DONTWAIT and tx flow off",
+				 __func__);
+			ret = -EAGAIN;
+			goto write_error;
+		}
+
+		/* release lock before waiting */
+		release_sock(&cf_sk->sk);
+
+		/* Wait until flow is on or socket is closed */
+		if (wait_event_interruptible(*cf_sk->sk.sk_sleep,
+					TX_FLOW_IS_ON(cf_sk)
+					|| !STATE_IS_OPEN(cf_sk)
+					|| STATE_IS_REMOTE_SHUTDOWN(cf_sk)
+					) == -ERESTARTSYS) {
+			pr_debug("CAIF: %s():"
+				 " wait_event_interruptible woken by a signal",
+				 __func__);
+			ret = -ERESTARTSYS;
+			goto write_error_no_unlock;
+		}
+
+		/* I want to be alone on cf_sk (except status and queue) */
+		lock_sock(&(cf_sk->sk));
+
+		if (!STATE_IS_OPEN(cf_sk)) {
+			/* someone closed the link, report error */
+			pr_debug("CAIF: %s(): remote end shutdown!\n",
+				      __func__);
+			ret = -EPIPE;
+			goto write_error;
+		}
+
+		if (STATE_IS_REMOTE_SHUTDOWN(cf_sk)) {
+			pr_debug("CAIF: %s(): "
+				 "received remote_shutdown indication\n",
+				 __func__);
+			ret = -ESHUTDOWN;
+			goto write_error;
+		}
+	}
+
+	pkt = cfpkt_create(payload_size);
+	skb = (struct sk_buff *)pkt;
+	skb->destructor = skb_destructor;
+	skb->sk = sk;
+	dbfs_atomic_inc(&cnt.skb_alloc);
+	dbfs_atomic_inc(&cnt.skb_in_use);
+	if (cfpkt_raw_append(pkt, (void **) &txbuf, payload_size) < 0) {
+		pr_debug("CAIF: %s(): cfpkt_raw_append failed\n", __func__);
+		cfpkt_destroy(pkt);
+		ret = -EINVAL;
+		goto write_error;
+	}
+
+	/* Copy data into buffer. */
+	if (copy_from_user(txbuf, msg->msg_iov->iov_base, payload_size)) {
+		pr_debug("CAIF: %s(): copy_from_user returned non zero.\n",
+			 __func__);
+		cfpkt_destroy(pkt);
+		ret = -EINVAL;
+		goto write_error;
+	}
+	memset(&info, 0, sizeof(info));
+
+	/* Send the packet down the stack. */
+	caif_assert(cf_sk->layer.dn);
+	caif_assert(cf_sk->layer.dn->transmit);
+
+	do {
+		ret = cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
+
+		if (likely((ret >= 0) || (ret != -EAGAIN)))
+			break;
+
+		/* EAGAIN - retry */
+		if (msg->msg_flags & MSG_DONTWAIT) {
+			pr_debug("CAIF: %s(): NONBLOCK and transmit failed,"
+				 " error = %ld\n", __func__, (long) ret);
+			ret = -EAGAIN;
+			goto write_error;
+		}
+
+		/* Let readers in */
+		release_sock(&cf_sk->sk);
+
+		/* Wait until flow is on or socket is closed */
+		if (wait_event_interruptible(*cf_sk->sk.sk_sleep,
+					TX_FLOW_IS_ON(cf_sk)
+					|| !STATE_IS_OPEN(cf_sk)
+					|| STATE_IS_REMOTE_SHUTDOWN(cf_sk)
+					) == -ERESTARTSYS) {
+			pr_debug("CAIF: %s(): wait_event_interruptible"
+				 " woken by a signal", __func__);
+			ret = -ERESTARTSYS;
+			goto write_error_no_unlock;
+		}
+
+		/* I want to be alone on cf_sk (except status and queue) */
+		lock_sock(&(cf_sk->sk));
+
+	} while (ret == -EAGAIN);
+
+	if (ret < 0) {
+		cfpkt_destroy(pkt);
+		pr_debug("CAIF: %s(): transmit failed, error = %ld\n",
+			 __func__, (long) ret);
+
+		goto write_error;
+	}
+
+	release_sock(&cf_sk->sk);
+	return payload_size;
+
+write_error:
+	release_sock(&cf_sk->sk);
+write_error_no_unlock:
+	return ret;
+}
+
+static unsigned int caif_poll(struct file *file, struct socket *sock,
+						poll_table *wait)
+{
+	struct sock *sk = sock->sk;
+	struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
+	u32 mask = 0;
+	poll_wait(file, sk->sk_sleep, wait);
+	lock_sock(&(cf_sk->sk));
+	if (!STATE_IS_OPEN(cf_sk)) {
+		if (!STATE_IS_PENDING(cf_sk))
+			mask |= POLLHUP;
+	} else {
+		if (cfpkt_qpeek(cf_sk->pktq) != NULL)
+			mask |= (POLLIN | POLLRDNORM);
+		if (TX_FLOW_IS_ON(cf_sk))
+			mask |= (POLLOUT | POLLWRNORM);
+	}
+	release_sock(&cf_sk->sk);
+	trace_printk("CAIF: %s(): poll mask=0x%04x\n",
+		      __func__, mask);
+	return mask;
+}
+
+static void drain_queue(struct caifsock *cf_sk)
+{
+	struct cfpkt *pkt = NULL;
+
+	/* Empty the queue */
+	do {
+		/* The queue has its own lock */
+		if (!cf_sk->pktq)
+			break;
+
+		pkt = cfpkt_dequeue(cf_sk->pktq);
+		if (!pkt)
+			break;
+		pr_debug("CAIF: %s(): freeing packet from read queue\n",
+			 __func__);
+		cfpkt_destroy(pkt);
+
+	} while (1);
+
+	cf_sk->read_queue_len = 0;
+}
+
+static int setsockopt(struct socket *sock,
+			int lvl, int opt, char __user *ov, unsigned int ol)
+{
+	struct sock *sk = sock->sk;
+	struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
+	int prio, linksel;
+	struct ifreq ifreq;
+
+	if (STATE_IS_OPEN(cf_sk)) {
+		pr_debug("CAIF: %s(): setsockopt "
+			 "cannot be done on a connected socket\n",
+			 __func__);
+		return -ENOPROTOOPT;
+	}
+	switch (opt) {
+	case CAIFSO_LINK_SELECT:
+		if (ol < sizeof(int)) {
+			pr_debug("CAIF: %s(): setsockopt"
+				 " CAIFSO_CHANNEL_CONFIG bad size\n", __func__);
+			return -EINVAL;
+		}
+		if (lvl != SOL_CAIF)
+			goto bad_sol;
+		if (copy_from_user(&linksel, ov, sizeof(int)))
+			return -EINVAL;
+		lock_sock(&(cf_sk->sk));
+		cf_sk->conn_req.link_selector = linksel;
+		release_sock(&cf_sk->sk);
+		return 0;
+
+	case SO_PRIORITY:
+		if (lvl != SOL_SOCKET)
+			goto bad_sol;
+		if (ol < sizeof(int)) {
+			pr_debug("CAIF: %s(): setsockopt"
+				 " SO_PRIORITY bad size\n", __func__);
+			return -EINVAL;
+		}
+		if (copy_from_user(&prio, ov, sizeof(int)))
+			return -EINVAL;
+		lock_sock(&(cf_sk->sk));
+		cf_sk->conn_req.priority = prio;
+		pr_debug("CAIF: %s(): Setting sockopt priority=%d\n", __func__,
+			cf_sk->conn_req.priority);
+		release_sock(&cf_sk->sk);
+		return 0;
+
+	case SO_BINDTODEVICE:
+		if (lvl != SOL_SOCKET)
+			goto bad_sol;
+		if (ol < sizeof(struct ifreq)) {
+			pr_debug("CAIF: %s(): setsockopt"
+				 " SO_PRIORITY bad size\n", __func__);
+			return -EINVAL;
+		}
+		if (copy_from_user(&ifreq, ov, sizeof(ifreq)))
+			return -EFAULT;
+		lock_sock(&(cf_sk->sk));
+		strncpy(cf_sk->conn_req.link_name, ifreq.ifr_name,
+			sizeof(cf_sk->conn_req.link_name));
+		cf_sk->conn_req.link_name
+			[sizeof(cf_sk->conn_req.link_name)-1] = 0;
+		release_sock(&cf_sk->sk);
+		return 0;
+
+	case CAIFSO_REQ_PARAM:
+		if (lvl != SOL_CAIF)
+			goto bad_sol;
+		if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
+			return -ENOPROTOOPT;
+		if (ol > sizeof(cf_sk->conn_req.param.data))
+			goto req_param_bad_size;
+
+		lock_sock(&(cf_sk->sk));
+		cf_sk->conn_req.param.size = ol;
+		if (copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
+			release_sock(&cf_sk->sk);
+req_param_bad_size:
+			pr_debug("CAIF: %s(): setsockopt"
+				 " CAIFSO_CHANNEL_CONFIG bad size\n", __func__);
+			return -EINVAL;
+		}
+
+		release_sock(&cf_sk->sk);
+		return 0;
+
+	default:
+		pr_debug("CAIF: %s(): unhandled option %d\n", __func__, opt);
+		return -EINVAL;
+	}
+
+	return 0;
+bad_sol:
+	pr_debug("CAIF: %s(): setsockopt bad level\n", __func__);
+	return -ENOPROTOOPT;
+
+}
+
+static int caif_connect(struct socket *sock, struct sockaddr *uservaddr,
+	       int sockaddr_len, int flags)
+{
+	struct caifsock *cf_sk = NULL;
+	int result = -1;
+	int mode = 0;
+	int ret = -EIO;
+	struct sock *sk = sock->sk;
+	BUG_ON(sk == NULL);
+
+	cf_sk = container_of(sk, struct caifsock, sk);
+
+	trace_printk("CAIF: %s(): cf_sk=%p OPEN=%d, TX_FLOW=%d, RX_FLOW=%d\n",
+		 __func__, cf_sk,
+		STATE_IS_OPEN(cf_sk),
+		TX_FLOW_IS_ON(cf_sk), RX_FLOW_IS_ON(cf_sk));
+
+
+	if (sock->type == SOCK_SEQPACKET || sock->type == SOCK_STREAM)
+		sock->state	= SS_CONNECTING;
+	else
+		goto out;
+
+	/* I want to be alone on cf_sk (except status and queue) */
+	lock_sock(&(cf_sk->sk));
+
+	if (sockaddr_len != sizeof(struct sockaddr_caif)) {
+		pr_debug("CAIF: %s(): Bad address len (%ld,%lu)\n",
+			 __func__, (long) sockaddr_len,
+			(long unsigned) sizeof(struct sockaddr_caif));
+		ret = -EINVAL;
+		goto open_error;
+	}
+
+	if (uservaddr->sa_family != AF_CAIF) {
+		pr_debug("CAIF: %s(): Bad address family (%d)\n",
+			 __func__, uservaddr->sa_family);
+		ret = -EAFNOSUPPORT;
+		goto open_error;
+	}
+
+	memcpy(&cf_sk->conn_req.sockaddr, uservaddr,
+		sizeof(struct sockaddr_caif));
+
+	dbfs_atomic_inc(&cnt.num_open);
+	mode = SKT_READ_FLAG | SKT_WRITE_FLAG;
+
+	/* If socket is not open, make sure socket is in fully closed state */
+	if (!STATE_IS_OPEN(cf_sk)) {
+		/* Has link close response been received (if we ever sent it)?*/
+		if (STATE_IS_PENDING(cf_sk)) {
+			/*
+			 * Still waiting for close response from remote.
+			 * If opened non-blocking, report "would block"
+			 */
+			if (flags & O_NONBLOCK) {
+				pr_debug("CAIF: %s(): O_NONBLOCK"
+					" && close pending\n", __func__);
+				ret = -EAGAIN;
+				goto open_error;
+			}
+
+			pr_debug("CAIF: %s(): Wait for close response"
+				 " from remote...\n", __func__);
+
+			release_sock(&cf_sk->sk);
+
+			/*
+			 * Blocking mode; close is pending and we need to wait
+			 * for its conclusion.
+			 */
+			result =
+			    wait_event_interruptible(*cf_sk->sk.sk_sleep,
+						     !STATE_IS_PENDING(cf_sk));
+
+			lock_sock(&(cf_sk->sk));
+			if (result == -ERESTARTSYS) {
+				pr_debug("CAIF: %s(): wait_event_interruptible"
+					 "woken by a signal (1)", __func__);
+				ret = -ERESTARTSYS;
+				goto open_error;
+			}
+		}
+	}
+
+	/* socket is now either closed, pending open or open */
+	if (STATE_IS_OPEN(cf_sk) && !STATE_IS_PENDING(cf_sk)) {
+		/* Open */
+		pr_debug("CAIF: %s(): Socket is already opened (cf_sk=%p)"
+			" check access f_flags = 0x%x file_mode = 0x%x\n",
+			 __func__, cf_sk, mode, cf_sk->file_mode);
+
+	} else {
+		/* We are closed or pending open.
+		 * If closed:	    send link setup
+		 * If pending open: link setup already sent (we could have been
+		 *		    interrupted by a signal last time)
+		 */
+		if (!STATE_IS_OPEN(cf_sk)) {
+			/* First opening of file; connect lower layers: */
+			/* Drain queue (very unlikely) */
+			drain_queue(cf_sk);
+
+			cf_sk->layer.receive = caif_sktrecv_cb;
+			SET_STATE_OPEN(cf_sk);
+			SET_PENDING_ON(cf_sk);
+
+			/* Register this channel. */
+			result =
+				caif_connect_client(&cf_sk->conn_req,
+							&cf_sk->layer);
+			if (result < 0) {
+				pr_debug("CAIF: %s(): can't register channel\n",
+					__func__);
+				ret = -EIO;
+				SET_STATE_CLOSED(cf_sk);
+				SET_PENDING_OFF(cf_sk);
+				goto open_error;
+			}
+			dbfs_atomic_inc(&cnt.num_init);
+		}
+
+		/* If opened non-blocking, report "success".
+		 */
+		if (flags & O_NONBLOCK) {
+			pr_debug("CAIF: %s(): O_NONBLOCK success\n",
+				 __func__);
+			ret = -EINPROGRESS;
+			cf_sk->sk.sk_err = -EINPROGRESS;
+			goto open_error;
+		}
+
+		trace_printk("CAIF: %s(): Wait for connect response\n",
+			     __func__);
+
+		/* release lock before waiting */
+		release_sock(&cf_sk->sk);
+
+		result =
+		    wait_event_interruptible(*cf_sk->sk.sk_sleep,
+					     !STATE_IS_PENDING(cf_sk));
+
+		lock_sock(&(cf_sk->sk));
+
+		if (result == -ERESTARTSYS) {
+			pr_debug("CAIF: %s(): wait_event_interruptible"
+				 "woken by a signal (2)", __func__);
+			ret = -ERESTARTSYS;
+			goto open_error;
+		}
+
+		if (!STATE_IS_OPEN(cf_sk)) {
+			/* Lower layers said "no" */
+			pr_debug("CAIF: %s(): Closed received\n", __func__);
+			ret = -EPIPE;
+			goto open_error;
+		}
+
+		trace_printk("CAIF: %s(): Connect received\n", __func__);
+	}
+	/* Open is ok */
+	cf_sk->file_mode |= mode;
+
+	trace_printk("CAIF: %s(): Connected - file mode = %x\n",
+		  __func__, cf_sk->file_mode);
+
+	release_sock(&cf_sk->sk);
+	return 0;
+open_error:
+	sock->state	= SS_UNCONNECTED;
+	release_sock(&cf_sk->sk);
+out:
+	return ret;
+}
+
+static int caif_shutdown(struct socket *sock, int how)
+{
+	struct caifsock *cf_sk = NULL;
+	int result = 0;
+	int tx_flow_state_was_on;
+	struct sock *sk = sock->sk;
+
+	trace_printk("CAIF: %s(): enter\n", __func__);
+	pr_debug("f_flags=%x\n", sock->file->f_flags);
+
+	if (how != SHUT_RDWR)
+		return -EOPNOTSUPP;
+
+	cf_sk = container_of(sk, struct caifsock, sk);
+	if (cf_sk == NULL) {
+		pr_debug("CAIF: %s(): COULD NOT FIND SOCKET\n", __func__);
+		return -EBADF;
+	}
+
+	/* I want to be alone on cf_sk (except status queue) */
+	lock_sock(&(cf_sk->sk));
+	sock_hold(&cf_sk->sk);
+
+	/* IS_CLOSED have double meaning:
+	 * 1) Spontanous Remote Shutdown Request.
+	 * 2) Ack on a channel teardown(disconnect)
+	 * Must clear bit in case we previously received
+	 * remote shudown request.
+	 */
+	if (STATE_IS_OPEN(cf_sk) && !STATE_IS_PENDING(cf_sk)) {
+		SET_STATE_CLOSED(cf_sk);
+		SET_PENDING_ON(cf_sk);
+		tx_flow_state_was_on = TX_FLOW_IS_ON(cf_sk);
+		SET_TX_FLOW_OFF(cf_sk);
+
+		/* Hold the socket until DEINIT_RSP is received */
+		sock_hold(&cf_sk->sk);
+		result = caif_disconnect_client(&cf_sk->layer);
+
+		if (result < 0) {
+			pr_debug("CAIF: %s(): "
+					"caif_disconnect_client() failed\n",
+					 __func__);
+			SET_STATE_CLOSED(cf_sk);
+			SET_PENDING_OFF(cf_sk);
+			SET_TX_FLOW_OFF(cf_sk);
+			release_sock(&cf_sk->sk);
+			sock_put(&cf_sk->sk);
+			return -EIO;
+		}
+
+	}
+	if (STATE_IS_REMOTE_SHUTDOWN(cf_sk)) {
+		SET_PENDING_OFF(cf_sk);
+		SET_REMOTE_SHUTDOWN_OFF(cf_sk);
+	}
+
+	/*
+	 * Socket is no longer in state pending close,
+	 * and we can release the reference.
+	 */
+
+	dbfs_atomic_inc(&cnt.num_close);
+	drain_queue(cf_sk);
+	SET_RX_FLOW_ON(cf_sk);
+	cf_sk->file_mode = 0;
+	sock_put(&cf_sk->sk);
+	release_sock(&cf_sk->sk);
+	if (!result && (sock->file->f_flags & O_NONBLOCK)) {
+		pr_debug("nonblocking shutdown returing -EAGAIN\n");
+		return -EAGAIN;
+	} else
+		return result;
+}
+
+static ssize_t caif_sock_no_sendpage(struct socket *sock,
+				     struct page *page,
+				     int offset, size_t size, int flags)
+{
+	return -EOPNOTSUPP;
+}
+
+/* This function is called as part of close. */
+static int caif_release(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+	struct caifsock *cf_sk = NULL;
+	int res;
+	caif_assert(sk != NULL);
+	cf_sk = container_of(sk, struct caifsock, sk);
+
+	if (cf_sk->debugfs_socket_dir != NULL)
+		debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
+
+	res = caif_shutdown(sock, SHUT_RDWR);
+	if (res && res != -EINPROGRESS)
+		return res;
+
+	/*
+	 * FIXME: Shutdown should probably be possible to do async
+	 * without flushing queues, allowing reception of frames while
+	 * waiting for DEINIT_IND.
+	 * Release should always block, to allow secure decoupling of
+	 * CAIF stack.
+	 */
+	if (!(sock->file->f_flags & O_NONBLOCK)) {
+		res = wait_event_interruptible(*cf_sk->sk.sk_sleep,
+						!STATE_IS_PENDING(cf_sk));
+
+		if (res == -ERESTARTSYS) {
+			pr_debug("CAIF: %s(): wait_event_interruptible"
+				"woken by a signal (1)", __func__);
+		}
+	}
+	lock_sock(&(cf_sk->sk));
+
+	sock->sk = NULL;
+
+	/* Detach the socket from its process context by making it orphan. */
+	sock_orphan(sk);
+
+	/*
+	 * Setting SHUTDOWN_MASK means that both send and receive are shutdown
+	 * for the socket.
+	 */
+	sk->sk_shutdown = SHUTDOWN_MASK;
+
+	/*
+	 * Set the socket state to closed, the TCP_CLOSE macro is used when
+	 * closing any socket.
+	 */
+
+	/* Flush out this sockets receive queue. */
+	drain_queue(cf_sk);
+
+	/* Finally release the socket. */
+	SET_STATE_PENDING_DESTROY(cf_sk);
+
+	release_sock(&cf_sk->sk);
+
+	sock_put(sk);
+
+	/*
+	 * The rest of the cleanup will be handled from the
+	 * caif_sock_destructor
+	 */
+	return res;
+}
+
+static const struct proto_ops caif_ops = {
+	.family = PF_CAIF,
+	.owner = THIS_MODULE,
+	.release = caif_release,
+	.bind = sock_no_bind,
+	.connect = caif_connect,
+	.socketpair = sock_no_socketpair,
+	.accept = sock_no_accept,
+	.getname = sock_no_getname,
+	.poll = caif_poll,
+	.ioctl = sock_no_ioctl,
+	.listen = sock_no_listen,
+	.shutdown = caif_shutdown,
+	.setsockopt = setsockopt,
+	.getsockopt = sock_no_getsockopt,
+	.sendmsg = caif_sendmsg,
+	.recvmsg = caif_recvmsg,
+	.mmap = sock_no_mmap,
+	.sendpage = caif_sock_no_sendpage,
+};
+
+/* This function is called when a socket is finally destroyed. */
+static void caif_sock_destructor(struct sock *sk)
+{
+	struct caifsock *cf_sk = NULL;
+	cf_sk = container_of(sk, struct caifsock, sk);
+	/* Error checks. */
+	caif_assert(!atomic_read(&sk->sk_wmem_alloc));
+	caif_assert(sk_unhashed(sk));
+	caif_assert(!sk->sk_socket);
+	if (!sock_flag(sk, SOCK_DEAD)) {
+		pr_debug("CAIF: %s(): 0x%p", __func__, sk);
+		return;
+	}
+
+	if (STATE_IS_OPEN(cf_sk)) {
+		pr_debug("CAIF: %s(): socket is opened (cf_sk=%p)"
+			 " file_mode = 0x%x\n", __func__,
+			 cf_sk, cf_sk->file_mode);
+		return;
+	}
+	drain_queue(cf_sk);
+	kfree(cf_sk->pktq);
+
+	trace_printk("CAIF: %s(): caif_sock_destructor: Removing socket %s\n",
+		__func__, cf_sk->name);
+	atomic_dec(&caif_nr_socks);
+}
+
+static int caif_create(struct net *net, struct socket *sock, int protocol,
+		       int kern)
+{
+	struct sock *sk = NULL;
+	struct caifsock *cf_sk = NULL;
+	int result = 0;
+	static struct proto prot = {.name = "PF_CAIF",
+		.owner = THIS_MODULE,
+		.obj_size = sizeof(struct caifsock),
+	};
+
+	/*
+	 * The sock->type specifies the socket type to use.
+	 * in SEQPACKET mode packet boundaries are enforced.
+	 */
+	if (sock->type != SOCK_SEQPACKET && sock->type != SOCK_STREAM)
+		return -ESOCKTNOSUPPORT;
+
+	if (net != &init_net)
+		return -EAFNOSUPPORT;
+
+	if (protocol < 0 || protocol >= CAIFPROTO_MAX)
+		return -EPROTONOSUPPORT;
+	/*
+	 * Set the socket state to unconnected.	 The socket state is really
+	 * not used at all in the net/core or socket.c but the
+	 * initialization makes sure that sock->state is not uninitialized.
+	 */
+	sock->state = SS_UNCONNECTED;
+
+	sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot);
+	if (!sk)
+		return -ENOMEM;
+
+	cf_sk = container_of(sk, struct caifsock, sk);
+
+	/* Store the protocol */
+	sk->sk_protocol = (unsigned char) protocol;
+
+	spin_lock_init(&cf_sk->read_queue_len_lock);
+
+	/* Fill in some information concerning the misc socket. */
+	snprintf(cf_sk->name, sizeof(cf_sk->name), "cf_sk%d",
+		atomic_read(&caif_nr_socks));
+
+	/*
+	 * Lock in order to try to stop someone from opening the socket
+	 * too early.
+	 */
+	lock_sock(&(cf_sk->sk));
+
+	/* Initialize the nozero default sock structure data. */
+	sock_init_data(sock, sk);
+	sock->ops = &caif_ops;
+	sk->sk_destruct = caif_sock_destructor;
+	sk->sk_sndbuf = caif_sockbuf_size;
+	sk->sk_rcvbuf = caif_sockbuf_size;
+
+	cf_sk->pktq = cfpktq_create();
+
+	if (!cf_sk->pktq) {
+		pr_err("CAIF: %s(): queue create failed.\n", __func__);
+		result = -ENOMEM;
+		release_sock(&cf_sk->sk);
+		goto err_failed;
+	}
+	cf_sk->layer.ctrlcmd = caif_sktflowctrl_cb;
+	SET_STATE_CLOSED(cf_sk);
+	SET_PENDING_OFF(cf_sk);
+	SET_TX_FLOW_OFF(cf_sk);
+	SET_RX_FLOW_ON(cf_sk);
+
+	/* Set default options on configuration */
+	cf_sk->conn_req.priority = CAIF_PRIO_NORMAL;
+	cf_sk->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
+	cf_sk->conn_req.protocol = protocol;
+	/* Increase the number of sockets created. */
+	atomic_inc(&caif_nr_socks);
+	if (!IS_ERR(debugfsdir)) {
+		cf_sk->debugfs_socket_dir =
+			debugfs_create_dir(cf_sk->name, debugfsdir);
+		debugfs_create_u32("conn_state", S_IRUSR | S_IWUSR,
+				cf_sk->debugfs_socket_dir, &cf_sk->conn_state);
+		debugfs_create_u32("flow_state", S_IRUSR | S_IWUSR,
+				cf_sk->debugfs_socket_dir, &cf_sk->flow_state);
+		debugfs_create_u32("read_queue_len", S_IRUSR | S_IWUSR,
+				cf_sk->debugfs_socket_dir,
+				(u32 *) &cf_sk->read_queue_len);
+		debugfs_create_u32("identity", S_IRUSR | S_IWUSR,
+				cf_sk->debugfs_socket_dir,
+				(u32 *) &cf_sk->layer.id);
+	}
+	release_sock(&cf_sk->sk);
+	return 0;
+err_failed:
+	sk_free(sk);
+	return result;
+}
+
+static struct net_proto_family caif_family_ops = {
+	.family = PF_CAIF,
+	.create = caif_create,
+	.owner = THIS_MODULE,
+};
+
+static int af_caif_init(void)
+{
+	int err;
+	err = sock_register(&caif_family_ops);
+
+	if (!err)
+		return err;
+
+	return 0;
+}
+
+static int __init caif_sktinit_module(void)
+{
+	int stat;
+#ifdef CONFIG_DEBUG_FS
+	debugfsdir = debugfs_create_dir("chnl_skt", NULL);
+	if (!IS_ERR(debugfsdir)) {
+		debugfs_create_u32("skb_inuse", S_IRUSR | S_IWUSR,
+				debugfsdir,
+				(u32 *) &cnt.skb_in_use);
+		debugfs_create_u32("skb_alloc", S_IRUSR | S_IWUSR,
+				debugfsdir,
+				(u32 *) &cnt.skb_alloc);
+		debugfs_create_u32("skb_free", S_IRUSR | S_IWUSR,
+				debugfsdir,
+				(u32 *) &cnt.skb_free);
+		debugfs_create_u32("num_sockets", S_IRUSR | S_IWUSR,
+				debugfsdir,
+				(u32 *) &caif_nr_socks);
+		debugfs_create_u32("num_open", S_IRUSR | S_IWUSR,
+				debugfsdir,
+				(u32 *) &cnt.num_open);
+		debugfs_create_u32("num_close", S_IRUSR | S_IWUSR,
+				debugfsdir,
+				(u32 *) &cnt.num_close);
+		debugfs_create_u32("num_init", S_IRUSR | S_IWUSR,
+				debugfsdir,
+				(u32 *) &cnt.num_init);
+		debugfs_create_u32("num_init_resp", S_IRUSR | S_IWUSR,
+				debugfsdir,
+				(u32 *) &cnt.num_init_resp);
+		debugfs_create_u32("num_init_fail_resp", S_IRUSR | S_IWUSR,
+				debugfsdir,
+				(u32 *) &cnt.num_init_fail_resp);
+		debugfs_create_u32("num_deinit", S_IRUSR | S_IWUSR,
+				debugfsdir,
+				(u32 *) &cnt.num_deinit);
+		debugfs_create_u32("num_deinit_resp", S_IRUSR | S_IWUSR,
+				debugfsdir,
+				(u32 *) &cnt.num_deinit_resp);
+		debugfs_create_u32("num_remote_shutdown_ind",
+				S_IRUSR | S_IWUSR, debugfsdir,
+				(u32 *) &cnt.num_remote_shutdown_ind);
+		debugfs_create_u32("num_tx_flow_off_ind", S_IRUSR | S_IWUSR,
+				debugfsdir,
+				(u32 *) &cnt.num_tx_flow_off_ind);
+		debugfs_create_u32("num_tx_flow_on_ind", S_IRUSR | S_IWUSR,
+				debugfsdir,
+				(u32 *) &cnt.num_tx_flow_on_ind);
+		debugfs_create_u32("num_rx_flow_off", S_IRUSR | S_IWUSR,
+				debugfsdir,
+				(u32 *) &cnt.num_rx_flow_off);
+		debugfs_create_u32("num_rx_flow_on", S_IRUSR | S_IWUSR,
+				debugfsdir,
+				(u32 *) &cnt.num_rx_flow_on);
+	}
+#endif
+	stat = af_caif_init();
+	if (stat) {
+		pr_err("CAIF: %s(): Failed to initialize CAIF socket layer.",
+		       __func__);
+		return stat;
+	}
+	return 0;
+}
+
+static void __exit caif_sktexit_module(void)
+{
+	sock_unregister(PF_CAIF);
+	if (debugfsdir != NULL)
+		debugfs_remove_recursive(debugfsdir);
+}
+
+module_init(caif_sktinit_module);
+module_exit(caif_sktexit_module);