net/caif/chnl_net.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) ST-Ericsson AB 2010
  * Authors:	Sjur Brendeland
  *		Daniel Martensson
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__

 #include <linux/fs.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/netdevice.h>
 #include <linux/if_ether.h>
 #include <linux/ip.h>
 #include <linux/sched.h>
 #include <linux/sockios.h>
 #include <linux/caif/if_caif.h>
 #include <net/rtnetlink.h>
 #include <net/caif/caif_layer.h>
 #include <net/caif/cfpkt.h>
 #include <net/caif/caif_dev.h>

 /* GPRS PDP connection has MTU to 1500 */
 #define GPRS_PDP_MTU 1500
 /* 5 sec. connect timeout */
 #define CONNECT_TIMEOUT (5 * HZ)
 #define CAIF_NET_DEFAULT_QUEUE_LEN 500
 #define UNDEF_CONNID 0xffffffff

 /*This list is protected by the rtnl lock. */
 static LIST_HEAD(chnl_net_list);

 MODULE_LICENSE("GPL");
 MODULE_ALIAS_RTNL_LINK("caif");

 enum caif_states {
 	CAIF_CONNECTED		= 1,
 	CAIF_CONNECTING,
 	CAIF_DISCONNECTED,
 	CAIF_SHUTDOWN
 };

 struct chnl_net {
 	struct cflayer chnl;
 	struct caif_connect_request conn_req;
 	struct list_head list_field;
 	struct net_device *netdev;
 	char name[256];
 	wait_queue_head_t netmgmt_wq;
 	/* Flow status to remember and control the transmission. */
 	bool flowenabled;
 	enum caif_states state;
 };

 static void robust_list_del(struct list_head *delete_node)
 {
 	struct list_head *list_node;
 	struct list_head *n;
 	ASSERT_RTNL();
 	list_for_each_safe(list_node, n, &chnl_net_list) {
 		if (list_node == delete_node) {
 			list_del(list_node);
 			return;
 		}
 	}
 	WARN_ON(1);
 }

 static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
 {
 	struct sk_buff *skb;
 	struct chnl_net *priv;
 	int pktlen;
 	const u8 *ip_version;
 	u8 buf;

 	priv = container_of(layr, struct chnl_net, chnl);
 	if (!priv)
 		return -EINVAL;

 	skb = (struct sk_buff *) cfpkt_tonative(pkt);

 	/* Get length of CAIF packet. */
 	pktlen = skb->len;

 	/* Pass some minimum information and
 	 * send the packet to the net stack.
 	 */
 	skb->dev = priv->netdev;

 	/* check the version of IP */
 	ip_version = skb_header_pointer(skb, 0, 1, &buf);
 	if (!ip_version) {
 		kfree_skb(skb);
 		return -EINVAL;
 	}

 	switch (*ip_version >> 4) {
 	case 4:
 		skb->protocol = htons(ETH_P_IP);
 		break;
 	case 6:
 		skb->protocol = htons(ETH_P_IPV6);
 		break;
 	default:
 		kfree_skb(skb);
 		priv->netdev->stats.rx_errors++;
 		return -EINVAL;
 	}

 	/* If we change the header in loop mode, the checksum is corrupted. */
 	if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 		skb->ip_summed = CHECKSUM_UNNECESSARY;
 	else
 		skb->ip_summed = CHECKSUM_NONE;

 	netif_rx_any_context(skb);

 	/* Update statistics. */
 	priv->netdev->stats.rx_packets++;
 	priv->netdev->stats.rx_bytes += pktlen;

 	return 0;
 }

 static int delete_device(struct chnl_net *dev)
 {
 	ASSERT_RTNL();
 	if (dev->netdev)
 		unregister_netdevice(dev->netdev);
 	return 0;
 }

 static void close_work(struct work_struct *work)
 {
 	struct chnl_net *dev = NULL;
 	struct list_head *list_node;
 	struct list_head *_tmp;

 	rtnl_lock();
 	list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 		dev = list_entry(list_node, struct chnl_net, list_field);
 		if (dev->state == CAIF_SHUTDOWN)
 			dev_close(dev->netdev);
 	}
 	rtnl_unlock();
 }
 static DECLARE_WORK(close_worker, close_work);

 static void chnl_hold(struct cflayer *lyr)
 {
 	struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 	dev_hold(priv->netdev);
 }

 static void chnl_put(struct cflayer *lyr)
 {
 	struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 	dev_put(priv->netdev);
 }

 static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
 			     int phyid)
 {
 	struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
 	pr_debug("NET flowctrl func called flow: %s\n",
 		flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
 		flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
 		flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
 		flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
 		flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
 		flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
 		 "REMOTE_SHUTDOWN" : "UNKNOWN CTRL COMMAND");


 	switch (flow) {
 	case CAIF_CTRLCMD_FLOW_OFF_IND:
 		priv->flowenabled = false;
 		netif_stop_queue(priv->netdev);
 		break;
 	case CAIF_CTRLCMD_DEINIT_RSP:
 		priv->state = CAIF_DISCONNECTED;
 		break;
 	case CAIF_CTRLCMD_INIT_FAIL_RSP:
 		priv->state = CAIF_DISCONNECTED;
 		wake_up_interruptible(&priv->netmgmt_wq);
 		break;
 	case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 		priv->state = CAIF_SHUTDOWN;
 		netif_tx_disable(priv->netdev);
 		schedule_work(&close_worker);
 		break;
 	case CAIF_CTRLCMD_FLOW_ON_IND:
 		priv->flowenabled = true;
 		netif_wake_queue(priv->netdev);
 		break;
 	case CAIF_CTRLCMD_INIT_RSP:
 		caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
 		priv->state = CAIF_CONNECTED;
 		priv->flowenabled = true;
 		netif_wake_queue(priv->netdev);
 		wake_up_interruptible(&priv->netmgmt_wq);
 		break;
 	default:
 		break;
 	}
 }

 static netdev_tx_t chnl_net_start_xmit(struct sk_buff *skb,
 				       struct net_device *dev)
 {
 	struct chnl_net *priv;
 	struct cfpkt *pkt = NULL;
 	int len;
 	int result = -1;
 	/* Get our private data. */
 	priv = netdev_priv(dev);

 	if (skb->len > priv->netdev->mtu) {
 		pr_warn("Size of skb exceeded MTU\n");
 		kfree_skb(skb);
 		dev->stats.tx_errors++;
 		return NETDEV_TX_OK;
 	}

 	if (!priv->flowenabled) {
 		pr_debug("dropping packets flow off\n");
 		kfree_skb(skb);
 		dev->stats.tx_dropped++;
 		return NETDEV_TX_OK;
 	}

 	if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 		swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);

 	/* Store original SKB length. */
 	len = skb->len;

 	pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);

 	/* Send the packet down the stack. */
 	result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
 	if (result) {
 		dev->stats.tx_dropped++;
 		return NETDEV_TX_OK;
 	}

 	/* Update statistics. */
 	dev->stats.tx_packets++;
 	dev->stats.tx_bytes += len;

 	return NETDEV_TX_OK;
 }

 static int chnl_net_open(struct net_device *dev)
 {
 	struct chnl_net *priv = NULL;
 	int result = -1;
 	int llifindex, headroom, tailroom, mtu;
 	struct net_device *lldev;
 	ASSERT_RTNL();
 	priv = netdev_priv(dev);
 	if (!priv) {
 		pr_debug("chnl_net_open: no priv\n");
 		return -ENODEV;
 	}

 	if (priv->state != CAIF_CONNECTING) {
 		priv->state = CAIF_CONNECTING;
 		result = caif_connect_client(dev_net(dev), &priv->conn_req,
 						&priv->chnl, &llifindex,
 						&headroom, &tailroom);
 		if (result != 0) {
 				pr_debug("err: "
 					 "Unable to register and open device,"
 					 " Err:%d\n",
 					 result);
 				goto error;
 		}

 		lldev = __dev_get_by_index(dev_net(dev), llifindex);

 		if (lldev == NULL) {
 			pr_debug("no interface?\n");
 			result = -ENODEV;
 			goto error;
 		}

 		dev->needed_tailroom = tailroom + lldev->needed_tailroom;
 		dev->hard_header_len = headroom + lldev->hard_header_len +
 			lldev->needed_tailroom;

 		/*
 		 * MTU, head-room etc is not know before we have a
 		 * CAIF link layer device available. MTU calculation may
 		 * override initial RTNL configuration.
 		 * MTU is minimum of current mtu, link layer mtu pluss
 		 * CAIF head and tail, and PDP GPRS contexts max MTU.
 		 */
 		mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
 		mtu = min_t(int, GPRS_PDP_MTU, mtu);
 		dev_set_mtu(dev, mtu);

 		if (mtu < 100) {
 			pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
 			result = -ENODEV;
 			goto error;
 		}
 	}

 	rtnl_unlock();  /* Release RTNL lock during connect wait */

 	result = wait_event_interruptible_timeout(priv->netmgmt_wq,
 						priv->state != CAIF_CONNECTING,
 						CONNECT_TIMEOUT);

 	rtnl_lock();

 	if (result == -ERESTARTSYS) {
 		pr_debug("wait_event_interruptible woken by a signal\n");
 		result = -ERESTARTSYS;
 		goto error;
 	}

 	if (result == 0) {
 		pr_debug("connect timeout\n");
 		caif_disconnect_client(dev_net(dev), &priv->chnl);
 		priv->state = CAIF_DISCONNECTED;
 		pr_debug("state disconnected\n");
 		result = -ETIMEDOUT;
 		goto error;
 	}

 	if (priv->state != CAIF_CONNECTED) {
 		pr_debug("connect failed\n");
 		result = -ECONNREFUSED;
 		goto error;
 	}
 	pr_debug("CAIF Netdevice connected\n");
 	return 0;

 error:
 	caif_disconnect_client(dev_net(dev), &priv->chnl);
 	priv->state = CAIF_DISCONNECTED;
 	pr_debug("state disconnected\n");
 	return result;

 }

 static int chnl_net_stop(struct net_device *dev)
 {
 	struct chnl_net *priv;

 	ASSERT_RTNL();
 	priv = netdev_priv(dev);
 	priv->state = CAIF_DISCONNECTED;
 	caif_disconnect_client(dev_net(dev), &priv->chnl);
 	return 0;
 }

 static int chnl_net_init(struct net_device *dev)
 {
 	struct chnl_net *priv;
 	ASSERT_RTNL();
 	priv = netdev_priv(dev);
 	strncpy(priv->name, dev->name, sizeof(priv->name));
 	return 0;
 }

 static void chnl_net_uninit(struct net_device *dev)
 {
 	struct chnl_net *priv;
 	ASSERT_RTNL();
 	priv = netdev_priv(dev);
 	robust_list_del(&priv->list_field);
 }

 static const struct net_device_ops netdev_ops = {
 	.ndo_open = chnl_net_open,
 	.ndo_stop = chnl_net_stop,
 	.ndo_init = chnl_net_init,
 	.ndo_uninit = chnl_net_uninit,
 	.ndo_start_xmit = chnl_net_start_xmit,
 };

 static void chnl_net_destructor(struct net_device *dev)
 {
 	struct chnl_net *priv = netdev_priv(dev);
 	caif_free_client(&priv->chnl);
 }

 static void ipcaif_net_setup(struct net_device *dev)
 {
 	struct chnl_net *priv;
 	dev->netdev_ops = &netdev_ops;
 	dev->needs_free_netdev = true;
 	dev->priv_destructor = chnl_net_destructor;
 	dev->flags |= IFF_NOARP;
 	dev->flags |= IFF_POINTOPOINT;
 	dev->mtu = GPRS_PDP_MTU;
 	dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;

 	priv = netdev_priv(dev);
 	priv->chnl.receive = chnl_recv_cb;
 	priv->chnl.ctrlcmd = chnl_flowctrl_cb;
 	priv->netdev = dev;
 	priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
 	priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
 	priv->conn_req.priority = CAIF_PRIO_LOW;
 	/* Insert illegal value */
 	priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
 	priv->flowenabled = false;

 	init_waitqueue_head(&priv->netmgmt_wq);
 }


 static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
 {
 	struct chnl_net *priv;
 	u8 loop;
 	priv = netdev_priv(dev);
 	if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
 			priv->conn_req.sockaddr.u.dgm.connection_id) ||
 	    nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
 			priv->conn_req.sockaddr.u.dgm.connection_id))
 		goto nla_put_failure;
 	loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
 	if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
 		goto nla_put_failure;
 	return 0;
 nla_put_failure:
 	return -EMSGSIZE;

 }

 static void caif_netlink_parms(struct nlattr *data[],
 			       struct caif_connect_request *conn_req)
 {
 	if (!data) {
 		pr_warn("no params data found\n");
 		return;
 	}
 	if (data[IFLA_CAIF_IPV4_CONNID])
 		conn_req->sockaddr.u.dgm.connection_id =
 			nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
 	if (data[IFLA_CAIF_IPV6_CONNID])
 		conn_req->sockaddr.u.dgm.connection_id =
 			nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
 	if (data[IFLA_CAIF_LOOPBACK]) {
 		if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
 			conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
 		else
 			conn_req->protocol = CAIFPROTO_DATAGRAM;
 	}
 }

 static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
 			  struct nlattr *tb[], struct nlattr *data[],
 			  struct netlink_ext_ack *extack)
 {
 	int ret;
 	struct chnl_net *caifdev;
 	ASSERT_RTNL();
 	caifdev = netdev_priv(dev);
 	caif_netlink_parms(data, &caifdev->conn_req);

 	ret = register_netdevice(dev);
 	if (ret)
 		pr_warn("device rtml registration failed\n");
 	else
 		list_add(&caifdev->list_field, &chnl_net_list);

 	/* Use ifindex as connection id, and use loopback channel default. */
 	if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
 		caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
 		caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
 	}
 	return ret;
 }

 static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
 			     struct nlattr *data[],
 			     struct netlink_ext_ack *extack)
 {
 	struct chnl_net *caifdev;
 	ASSERT_RTNL();
 	caifdev = netdev_priv(dev);
 	caif_netlink_parms(data, &caifdev->conn_req);
 	netdev_state_change(dev);
 	return 0;
 }

 static size_t ipcaif_get_size(const struct net_device *dev)
 {
 	return
 		/* IFLA_CAIF_IPV4_CONNID */
 		nla_total_size(4) +
 		/* IFLA_CAIF_IPV6_CONNID */
 		nla_total_size(4) +
 		/* IFLA_CAIF_LOOPBACK */
 		nla_total_size(2) +
 		0;
 }

 static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
 	[IFLA_CAIF_IPV4_CONNID]	      = { .type = NLA_U32 },
 	[IFLA_CAIF_IPV6_CONNID]	      = { .type = NLA_U32 },
 	[IFLA_CAIF_LOOPBACK]	      = { .type = NLA_U8 }
 };


 static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
 	.kind		= "caif",
 	.priv_size	= sizeof(struct chnl_net),
 	.setup		= ipcaif_net_setup,
 	.maxtype	= IFLA_CAIF_MAX,
 	.policy		= ipcaif_policy,
 	.newlink	= ipcaif_newlink,
 	.changelink	= ipcaif_changelink,
 	.get_size	= ipcaif_get_size,
 	.fill_info	= ipcaif_fill_info,

 };

 static int __init chnl_init_module(void)
 {
 	return rtnl_link_register(&ipcaif_link_ops);
 }

 static void __exit chnl_exit_module(void)
 {
 	struct chnl_net *dev = NULL;
 	struct list_head *list_node;
 	struct list_head *_tmp;
 	rtnl_link_unregister(&ipcaif_link_ops);
 	rtnl_lock();
 	list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 		dev = list_entry(list_node, struct chnl_net, list_field);
 		list_del(list_node);
 		delete_device(dev);
 	}
 	rtnl_unlock();
 }

 module_init(chnl_init_module);
 module_exit(chnl_exit_module);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (C) ST-Ericsson AB 2010
	* Authors: Sjur Brendeland
	* Daniel Martensson
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__

	#include <linux/fs.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/netdevice.h>
	#include <linux/if_ether.h>
	#include <linux/ip.h>
	#include <linux/sched.h>
	#include <linux/sockios.h>
	#include <linux/caif/if_caif.h>
	#include <net/rtnetlink.h>
	#include <net/caif/caif_layer.h>
	#include <net/caif/cfpkt.h>
	#include <net/caif/caif_dev.h>

	/* GPRS PDP connection has MTU to 1500 */
	#define GPRS_PDP_MTU 1500
	/* 5 sec. connect timeout */
	#define CONNECT_TIMEOUT (5 * HZ)
	#define CAIF_NET_DEFAULT_QUEUE_LEN 500
	#define UNDEF_CONNID 0xffffffff

	/This list is protected by the rtnl lock. /
	static LIST_HEAD(chnl_net_list);

	MODULE_LICENSE("GPL");
	MODULE_ALIAS_RTNL_LINK("caif");

	enum caif_states {
	CAIF_CONNECTED = 1,
	CAIF_CONNECTING,
	CAIF_DISCONNECTED,
	CAIF_SHUTDOWN
	};

	struct chnl_net {
	struct cflayer chnl;
	struct caif_connect_request conn_req;
	struct list_head list_field;
	struct net_device *netdev;
	char name[256];
	wait_queue_head_t netmgmt_wq;
	/* Flow status to remember and control the transmission. */
	bool flowenabled;
	enum caif_states state;
	};

	static void robust_list_del(struct list_head *delete_node)
	{
	struct list_head *list_node;
	struct list_head *n;
	ASSERT_RTNL();
	list_for_each_safe(list_node, n, &chnl_net_list) {
	if (list_node == delete_node) {
	list_del(list_node);
	return;
	}
	}
	WARN_ON(1);
	}

	static int chnl_recv_cb(struct cflayer layr, struct cfpkt pkt)
	{
	struct sk_buff *skb;
	struct chnl_net *priv;
	int pktlen;
	const u8 *ip_version;
	u8 buf;

	priv = container_of(layr, struct chnl_net, chnl);
	if (!priv)
	return -EINVAL;

	skb = (struct sk_buff *) cfpkt_tonative(pkt);

	/* Get length of CAIF packet. */
	pktlen = skb->len;

	/* Pass some minimum information and
	* send the packet to the net stack.
	*/
	skb->dev = priv->netdev;

	/* check the version of IP */
	ip_version = skb_header_pointer(skb, 0, 1, &buf);
	if (!ip_version) {
	kfree_skb(skb);
	return -EINVAL;
	}

	switch (*ip_version >> 4) {
	case 4:
	skb->protocol = htons(ETH_P_IP);
	break;
	case 6:
	skb->protocol = htons(ETH_P_IPV6);
	break;
	default:
	kfree_skb(skb);
	priv->netdev->stats.rx_errors++;
	return -EINVAL;
	}

	/* If we change the header in loop mode, the checksum is corrupted. */
	if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
	skb->ip_summed = CHECKSUM_UNNECESSARY;
	else
	skb->ip_summed = CHECKSUM_NONE;

	netif_rx_any_context(skb);

	/* Update statistics. */
	priv->netdev->stats.rx_packets++;
	priv->netdev->stats.rx_bytes += pktlen;

	return 0;
	}

	static int delete_device(struct chnl_net *dev)
	{
	ASSERT_RTNL();
	if (dev->netdev)
	unregister_netdevice(dev->netdev);
	return 0;
	}

	static void close_work(struct work_struct *work)
	{
	struct chnl_net *dev = NULL;
	struct list_head *list_node;
	struct list_head *_tmp;

	rtnl_lock();
	list_for_each_safe(list_node, _tmp, &chnl_net_list) {
	dev = list_entry(list_node, struct chnl_net, list_field);
	if (dev->state == CAIF_SHUTDOWN)
	dev_close(dev->netdev);
	}
	rtnl_unlock();
	}
	static DECLARE_WORK(close_worker, close_work);

	static void chnl_hold(struct cflayer *lyr)
	{
	struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
	dev_hold(priv->netdev);
	}

	static void chnl_put(struct cflayer *lyr)
	{
	struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
	dev_put(priv->netdev);
	}

	static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
	int phyid)
	{
	struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
	pr_debug("NET flowctrl func called flow: %s\n",
	flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
	flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
	flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
	flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
	flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
	flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
	"REMOTE_SHUTDOWN" : "UNKNOWN CTRL COMMAND");



	switch (flow) {
	case CAIF_CTRLCMD_FLOW_OFF_IND:
	priv->flowenabled = false;
	netif_stop_queue(priv->netdev);
	break;
	case CAIF_CTRLCMD_DEINIT_RSP:
	priv->state = CAIF_DISCONNECTED;
	break;
	case CAIF_CTRLCMD_INIT_FAIL_RSP:
	priv->state = CAIF_DISCONNECTED;
	wake_up_interruptible(&priv->netmgmt_wq);
	break;
	case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
	priv->state = CAIF_SHUTDOWN;
	netif_tx_disable(priv->netdev);
	schedule_work(&close_worker);
	break;
	case CAIF_CTRLCMD_FLOW_ON_IND:
	priv->flowenabled = true;
	netif_wake_queue(priv->netdev);
	break;
	case CAIF_CTRLCMD_INIT_RSP:
	caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
	priv->state = CAIF_CONNECTED;
	priv->flowenabled = true;
	netif_wake_queue(priv->netdev);
	wake_up_interruptible(&priv->netmgmt_wq);
	break;
	default:
	break;
	}
	}

	static netdev_tx_t chnl_net_start_xmit(struct sk_buff *skb,
	struct net_device *dev)
	{
	struct chnl_net *priv;
	struct cfpkt *pkt = NULL;
	int len;
	int result = -1;
	/* Get our private data. */
	priv = netdev_priv(dev);

	if (skb->len > priv->netdev->mtu) {
	pr_warn("Size of skb exceeded MTU\n");
	kfree_skb(skb);
	dev->stats.tx_errors++;
	return NETDEV_TX_OK;
	}

	if (!priv->flowenabled) {
	pr_debug("dropping packets flow off\n");
	kfree_skb(skb);
	dev->stats.tx_dropped++;
	return NETDEV_TX_OK;
	}

	if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
	swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);

	/* Store original SKB length. */
	len = skb->len;

	pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);

	/* Send the packet down the stack. */
	result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
	if (result) {
	dev->stats.tx_dropped++;
	return NETDEV_TX_OK;
	}

	/* Update statistics. */
	dev->stats.tx_packets++;
	dev->stats.tx_bytes += len;

	return NETDEV_TX_OK;
	}

	static int chnl_net_open(struct net_device *dev)
	{
	struct chnl_net *priv = NULL;
	int result = -1;
	int llifindex, headroom, tailroom, mtu;
	struct net_device *lldev;
	ASSERT_RTNL();
	priv = netdev_priv(dev);
	if (!priv) {
	pr_debug("chnl_net_open: no priv\n");
	return -ENODEV;
	}

	if (priv->state != CAIF_CONNECTING) {
	priv->state = CAIF_CONNECTING;
	result = caif_connect_client(dev_net(dev), &priv->conn_req,
	&priv->chnl, &llifindex,
	&headroom, &tailroom);
	if (result != 0) {
	pr_debug("err: "
	"Unable to register and open device,"
	" Err:%d\n",
	result);
	goto error;
	}

	lldev = __dev_get_by_index(dev_net(dev), llifindex);

	if (lldev == NULL) {
	pr_debug("no interface?\n");
	result = -ENODEV;
	goto error;
	}

	dev->needed_tailroom = tailroom + lldev->needed_tailroom;
	dev->hard_header_len = headroom + lldev->hard_header_len +
	lldev->needed_tailroom;

	/*
	* MTU, head-room etc is not know before we have a
	* CAIF link layer device available. MTU calculation may
	* override initial RTNL configuration.
	* MTU is minimum of current mtu, link layer mtu pluss
	* CAIF head and tail, and PDP GPRS contexts max MTU.
	*/
	mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
	mtu = min_t(int, GPRS_PDP_MTU, mtu);
	dev_set_mtu(dev, mtu);

	if (mtu < 100) {
	pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
	result = -ENODEV;
	goto error;
	}
	}

	rtnl_unlock(); /* Release RTNL lock during connect wait */

	result = wait_event_interruptible_timeout(priv->netmgmt_wq,
	priv->state != CAIF_CONNECTING,
	CONNECT_TIMEOUT);

	rtnl_lock();

	if (result == -ERESTARTSYS) {
	pr_debug("wait_event_interruptible woken by a signal\n");
	result = -ERESTARTSYS;
	goto error;
	}

	if (result == 0) {
	pr_debug("connect timeout\n");
	caif_disconnect_client(dev_net(dev), &priv->chnl);
	priv->state = CAIF_DISCONNECTED;
	pr_debug("state disconnected\n");
	result = -ETIMEDOUT;
	goto error;
	}

	if (priv->state != CAIF_CONNECTED) {
	pr_debug("connect failed\n");
	result = -ECONNREFUSED;
	goto error;
	}
	pr_debug("CAIF Netdevice connected\n");
	return 0;

	error:
	caif_disconnect_client(dev_net(dev), &priv->chnl);
	priv->state = CAIF_DISCONNECTED;
	pr_debug("state disconnected\n");
	return result;

	}

	static int chnl_net_stop(struct net_device *dev)
	{
	struct chnl_net *priv;

	ASSERT_RTNL();
	priv = netdev_priv(dev);
	priv->state = CAIF_DISCONNECTED;
	caif_disconnect_client(dev_net(dev), &priv->chnl);
	return 0;
	}

	static int chnl_net_init(struct net_device *dev)
	{
	struct chnl_net *priv;
	ASSERT_RTNL();
	priv = netdev_priv(dev);
	strncpy(priv->name, dev->name, sizeof(priv->name));
	return 0;
	}

	static void chnl_net_uninit(struct net_device *dev)
	{
	struct chnl_net *priv;
	ASSERT_RTNL();
	priv = netdev_priv(dev);
	robust_list_del(&priv->list_field);
	}

	static const struct net_device_ops netdev_ops = {
	.ndo_open = chnl_net_open,
	.ndo_stop = chnl_net_stop,
	.ndo_init = chnl_net_init,
	.ndo_uninit = chnl_net_uninit,
	.ndo_start_xmit = chnl_net_start_xmit,
	};

	static void chnl_net_destructor(struct net_device *dev)
	{
	struct chnl_net *priv = netdev_priv(dev);
	caif_free_client(&priv->chnl);
	}

	static void ipcaif_net_setup(struct net_device *dev)
	{
	struct chnl_net *priv;
	dev->netdev_ops = &netdev_ops;
	dev->needs_free_netdev = true;
	dev->priv_destructor = chnl_net_destructor;
	dev->flags \|= IFF_NOARP;
	dev->flags \|= IFF_POINTOPOINT;
	dev->mtu = GPRS_PDP_MTU;
	dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;

	priv = netdev_priv(dev);
	priv->chnl.receive = chnl_recv_cb;
	priv->chnl.ctrlcmd = chnl_flowctrl_cb;
	priv->netdev = dev;
	priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
	priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
	priv->conn_req.priority = CAIF_PRIO_LOW;
	/* Insert illegal value */
	priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
	priv->flowenabled = false;

	init_waitqueue_head(&priv->netmgmt_wq);
	}


	static int ipcaif_fill_info(struct sk_buff skb, const struct net_device dev)
	{
	struct chnl_net *priv;
	u8 loop;
	priv = netdev_priv(dev);
	if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
	priv->conn_req.sockaddr.u.dgm.connection_id) \|\|
	nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
	priv->conn_req.sockaddr.u.dgm.connection_id))
	goto nla_put_failure;
	loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
	if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
	goto nla_put_failure;
	return 0;
	nla_put_failure:
	return -EMSGSIZE;

	}

	static void caif_netlink_parms(struct nlattr *data[],
	struct caif_connect_request *conn_req)
	{
	if (!data) {
	pr_warn("no params data found\n");
	return;
	}
	if (data[IFLA_CAIF_IPV4_CONNID])
	conn_req->sockaddr.u.dgm.connection_id =
	nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
	if (data[IFLA_CAIF_IPV6_CONNID])
	conn_req->sockaddr.u.dgm.connection_id =
	nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
	if (data[IFLA_CAIF_LOOPBACK]) {
	if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
	conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
	else
	conn_req->protocol = CAIFPROTO_DATAGRAM;
	}
	}

	static int ipcaif_newlink(struct net src_net, struct net_device dev,
	struct nlattr tb[], struct nlattr data[],
	struct netlink_ext_ack *extack)
	{
	int ret;
	struct chnl_net *caifdev;
	ASSERT_RTNL();
	caifdev = netdev_priv(dev);
	caif_netlink_parms(data, &caifdev->conn_req);

	ret = register_netdevice(dev);
	if (ret)
	pr_warn("device rtml registration failed\n");
	else
	list_add(&caifdev->list_field, &chnl_net_list);

	/* Use ifindex as connection id, and use loopback channel default. */
	if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
	caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
	caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
	}
	return ret;
	}

	static int ipcaif_changelink(struct net_device dev, struct nlattr tb[],
	struct nlattr *data[],
	struct netlink_ext_ack *extack)
	{
	struct chnl_net *caifdev;
	ASSERT_RTNL();
	caifdev = netdev_priv(dev);
	caif_netlink_parms(data, &caifdev->conn_req);
	netdev_state_change(dev);
	return 0;
	}

	static size_t ipcaif_get_size(const struct net_device *dev)
	{
	return
	/* IFLA_CAIF_IPV4_CONNID */
	nla_total_size(4) +
	/* IFLA_CAIF_IPV6_CONNID */
	nla_total_size(4) +
	/* IFLA_CAIF_LOOPBACK */
	nla_total_size(2) +
	0;
	}

	static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
	[IFLA_CAIF_IPV4_CONNID] = { .type = NLA_U32 },
	[IFLA_CAIF_IPV6_CONNID] = { .type = NLA_U32 },
	[IFLA_CAIF_LOOPBACK] = { .type = NLA_U8 }
	};


	static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
	.kind = "caif",
	.priv_size = sizeof(struct chnl_net),
	.setup = ipcaif_net_setup,
	.maxtype = IFLA_CAIF_MAX,
	.policy = ipcaif_policy,
	.newlink = ipcaif_newlink,
	.changelink = ipcaif_changelink,
	.get_size = ipcaif_get_size,
	.fill_info = ipcaif_fill_info,

	};

	static int __init chnl_init_module(void)
	{
	return rtnl_link_register(&ipcaif_link_ops);
	}

	static void __exit chnl_exit_module(void)
	{
	struct chnl_net *dev = NULL;
	struct list_head *list_node;
	struct list_head *_tmp;
	rtnl_link_unregister(&ipcaif_link_ops);
	rtnl_lock();
	list_for_each_safe(list_node, _tmp, &chnl_net_list) {
	dev = list_entry(list_node, struct chnl_net, list_field);
	list_del(list_node);
	delete_device(dev);
	}
	rtnl_unlock();
	}

	module_init(chnl_init_module);
	module_exit(chnl_exit_module);