net-caif: add CAIF netdevice

Adding GPRS Net Device for PDP Contexts.
The device can be managed by RTNL as defined in if_caif.h.
Signed-off-by: NSjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/caif/chnl_net.c

+/*
+ * Copyright (C) ST-Ericsson AB 2010
+ * Authors:	Sjur Brendeland/sjur.brandeland@stericsson.com
+ *		Daniel Martensson / Daniel.Martensson@stericsson.com
+ * License terms: GNU General Public License (GPL) version 2
+ */
+
+#include <linux/version.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/if_ether.h>
+#include <linux/moduleparam.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/cfcnfg.h>
+#include <net/caif/cfpkt.h>
+#include <net/caif/caif_dev.h>
+
+#define CAIF_CONNECT_TIMEOUT 30
+#define SIZE_MTU 1500
+#define SIZE_MTU_MAX 4080
+#define SIZE_MTU_MIN 68
+#define CAIF_NET_DEFAULT_QUEUE_LEN 500
+
+#undef pr_debug
+#define pr_debug pr_warning
+
+/*This list is protected by the rtnl lock. */
+static LIST_HEAD(chnl_net_list);
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_RTNL_LINK("caif");
+
+struct chnl_net {
+	struct cflayer chnl;
+	struct net_device_stats stats;
+	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;
+	bool pending_close;
+};
+
+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);
+			break;
+		}
+	}
+}
+
+static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
+{
+	struct sk_buff *skb;
+	struct chnl_net *priv  = NULL;
+	int pktlen;
+	int err = 0;
+
+	priv = container_of(layr, struct chnl_net, chnl);
+
+	if (!priv)
+		return -EINVAL;
+
+	/* Get length of CAIF packet. */
+	pktlen = cfpkt_getlen(pkt);
+
+	skb = (struct sk_buff *) cfpkt_tonative(pkt);
+	/* Pass some minimum information and
+	 * send the packet to the net stack.
+	 */
+	skb->dev = priv->netdev;
+	skb->protocol = htons(ETH_P_IP);
+
+	/* 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;
+
+	/* FIXME: Drivers should call this in tasklet context. */
+	if (in_interrupt())
+		netif_rx(skb);
+	else
+		netif_rx_ni(skb);
+
+	/* Update statistics. */
+	priv->netdev->stats.rx_packets++;
+	priv->netdev->stats.rx_bytes += pktlen;
+
+	return err;
+}
+
+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->pending_close)
+			continue;
+		list_del(list_node);
+		delete_device(dev);
+	}
+	rtnl_unlock();
+}
+static DECLARE_WORK(close_worker, close_work);
+
+static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
+				int phyid)
+{
+	struct chnl_net *priv;
+	pr_debug("CAIF: %s(): NET flowctrl func called flow: %s.\n",
+		__func__,
+		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" : "UKNOWN CTRL COMMAND");
+
+	priv = container_of(layr, struct chnl_net, chnl);
+
+	switch (flow) {
+	case CAIF_CTRLCMD_FLOW_OFF_IND:
+	case CAIF_CTRLCMD_DEINIT_RSP:
+	case CAIF_CTRLCMD_INIT_FAIL_RSP:
+	case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
+		priv->flowenabled = false;
+		netif_tx_disable(priv->netdev);
+		pr_warning("CAIF: %s(): done\n", __func__);
+		priv->pending_close = 1;
+		schedule_work(&close_worker);
+		break;
+	case CAIF_CTRLCMD_FLOW_ON_IND:
+	case CAIF_CTRLCMD_INIT_RSP:
+		priv->flowenabled = true;
+		netif_wake_queue(priv->netdev);
+		wake_up_interruptible(&priv->netmgmt_wq);
+		break;
+	default:
+		break;
+	}
+}
+
+static int 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_warning("CAIF: %s(): Size of skb exceeded MTU\n", __func__);
+		return -ENOSPC;
+	}
+
+	if (!priv->flowenabled) {
+		pr_debug("CAIF: %s(): dropping packets flow off\n", __func__);
+		return NETDEV_TX_BUSY;
+	}
+
+	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);
+
+	pr_debug("CAIF: %s(): transmit inst %s %d,%p\n",
+		__func__, dev->name, priv->chnl.dn->id, &priv->chnl.dn);
+
+	/* Send the packet down the stack. */
+	result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
+	if (result) {
+		if (result == -EAGAIN)
+			result = NETDEV_TX_BUSY;
+		return result;
+	}
+
+	/* 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;
+	ASSERT_RTNL();
+
+	priv = netdev_priv(dev);
+	pr_debug("CAIF: %s(): dev name: %s\n", __func__, priv->name);
+
+	if (!priv) {
+		pr_debug("CAIF: %s(): chnl_net_open: no priv\n", __func__);
+		return -ENODEV;
+	}
+	result = caif_connect_client(&priv->conn_req, &priv->chnl);
+	if (result != 0) {
+		pr_debug("CAIF: %s(): err: "
+			 "Unable to register and open device, Err:%d\n",
+			__func__,
+			result);
+		return -ENODEV;
+	}
+	result = wait_event_interruptible(priv->netmgmt_wq, priv->flowenabled);
+
+	if (result == -ERESTARTSYS) {
+		pr_debug("CAIF: %s(): wait_event_interruptible"
+			 " woken by a signal\n", __func__);
+		return -ERESTARTSYS;
+	} else
+		pr_debug("CAIF: %s(): Flow on recieved\n", __func__);
+
+	return 0;
+}
+
+static int chnl_net_stop(struct net_device *dev)
+{
+	struct chnl_net *priv;
+	int result = -1;
+	ASSERT_RTNL();
+	priv = netdev_priv(dev);
+
+	result = caif_disconnect_client(&priv->chnl);
+	if (result != 0) {
+		pr_debug("CAIF: %s(): chnl_net_stop: err: "
+			 "Unable to STOP device, Err:%d\n",
+			 __func__, result);
+		return -EBUSY;
+	}
+	result = wait_event_interruptible(priv->netmgmt_wq,
+					  !priv->flowenabled);
+
+	if (result == -ERESTARTSYS) {
+		pr_debug("CAIF: %s(): wait_event_interruptible woken by"
+			 " signal, signal_pending(current) = %d\n",
+			 __func__,
+			 signal_pending(current));
+	} else {
+		pr_debug("CAIF: %s(): disconnect received\n", __func__);
+
+	}
+
+	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 ipcaif_net_setup(struct net_device *dev)
+{
+	struct chnl_net *priv;
+	dev->netdev_ops = &netdev_ops;
+	dev->destructor = free_netdev;
+	dev->flags |= IFF_NOARP;
+	dev->flags |= IFF_POINTOPOINT;
+	dev->needed_headroom = CAIF_NEEDED_HEADROOM;
+	dev->needed_tailroom = CAIF_NEEDED_TAILROOM;
+	dev->mtu = SIZE_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 = -1;
+	priv->flowenabled = false;
+
+	ASSERT_RTNL();
+	init_waitqueue_head(&priv->netmgmt_wq);
+	list_add(&priv->list_field, &chnl_net_list);
+}
+
+
+static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
+{
+	struct chnl_net *priv;
+	u8 loop;
+	priv = netdev_priv(dev);
+	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);
+	loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
+	NLA_PUT_U8(skb, IFLA_CAIF_LOOPBACK, loop);
+
+
+	return 0;
+nla_put_failure:
+	return -EMSGSIZE;
+
+}
+
+static void caif_netlink_parms(struct nlattr *data[],
+				struct caif_connect_request *conn_req)
+{
+	if (!data) {
+		pr_warning("CAIF: %s: no params data found\n", __func__);
+		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[])
+{
+	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_warning("CAIF: %s(): device rtml registration failed\n",
+			   __func__);
+	return ret;
+}
+
+static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
+				struct nlattr *data[])
+{
+	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);