Phonet: network device and address handling

This provides support for adding Phonet addresses to and removing
Phonet addresses from network devices.
Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/phonet/pn_dev.h

+/*
+ * File: pn_dev.h
+ *
+ * Phonet network device
+ *
+ * Copyright (C) 2008 Nokia Corporation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#ifndef PN_DEV_H
+#define PN_DEV_H
+
+struct phonet_device_list {
+	struct list_head list;
+	spinlock_t lock;
+};
+
+extern struct phonet_device_list pndevs;
+
+struct phonet_device {
+	struct list_head list;
+	struct net_device *netdev;
+	DECLARE_BITMAP(addrs, 64);
+};
+
+void phonet_device_init(void);
+void phonet_device_exit(void);
+struct net_device *phonet_device_get(struct net *net);
+
+int phonet_address_add(struct net_device *dev, u8 addr);
+int phonet_address_del(struct net_device *dev, u8 addr);
+u8 phonet_address_get(struct net_device *dev, u8 addr);
+int phonet_address_lookup(u8 addr);
+
+#define PN_NO_ADDR	0xff
+
+#endif

net/phonet/Makefile

 obj-$(CONFIG_PHONET) += phonet.o
 
 phonet-objs := \
+	pn_dev.o \
 	af_phonet.o

net/phonet/af_phonet.c

@@ -31,6 +31,7 @@
 #include <linux/if_phonet.h>
 #include <linux/phonet.h>
 #include <net/phonet/phonet.h>
+#include <net/phonet/pn_dev.h>
 
 static struct net_proto_family phonet_proto_family;
 static struct phonet_protocol *phonet_proto_get(int protocol);
@@ -200,6 +201,7 @@ static int __init phonet_init(void)
 		return err;
 	}
 
+	phonet_device_init();
 	dev_add_pack(&phonet_packet_type);
 	return 0;
 }
@@ -208,6 +210,7 @@ static void __exit phonet_exit(void)
 {
 	sock_unregister(AF_PHONET);
 	dev_remove_pack(&phonet_packet_type);
+	phonet_device_exit();
 }
 
 module_init(phonet_init);

net/phonet/pn_dev.c

+/*
+ * File: pn_dev.c
+ *
+ * Phonet network device
+ *
+ * Copyright (C) 2008 Nokia Corporation.
+ *
+ * Contact: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
+ * Original author: Sakari Ailus <sakari.ailus@nokia.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/phonet.h>
+#include <net/sock.h>
+#include <net/phonet/pn_dev.h>
+
+/* when accessing, remember to lock with spin_lock(&pndevs.lock); */
+struct phonet_device_list pndevs = {
+	.list = LIST_HEAD_INIT(pndevs.list),
+	.lock = __SPIN_LOCK_UNLOCKED(pndevs.lock),
+};
+
+/* Allocate new Phonet device. */
+static struct phonet_device *__phonet_device_alloc(struct net_device *dev)
+{
+	struct phonet_device *pnd = kmalloc(sizeof(*pnd), GFP_ATOMIC);
+	if (pnd == NULL)
+		return NULL;
+	pnd->netdev = dev;
+	bitmap_zero(pnd->addrs, 64);
+
+	list_add(&pnd->list, &pndevs.list);
+	return pnd;
+}
+
+static struct phonet_device *__phonet_get(struct net_device *dev)
+{
+	struct phonet_device *pnd;
+
+	list_for_each_entry(pnd, &pndevs.list, list) {
+		if (pnd->netdev == dev)
+			return pnd;
+	}
+	return NULL;
+}
+
+static void __phonet_device_free(struct phonet_device *pnd)
+{
+	list_del(&pnd->list);
+	kfree(pnd);
+}
+
+struct net_device *phonet_device_get(struct net *net)
+{
+	struct phonet_device *pnd;
+	struct net_device *dev;
+
+	spin_lock_bh(&pndevs.lock);
+	list_for_each_entry(pnd, &pndevs.list, list) {
+		dev = pnd->netdev;
+		BUG_ON(!dev);
+
+		if (dev_net(dev) == net &&
+			(dev->reg_state == NETREG_REGISTERED) &&
+			((pnd->netdev->flags & IFF_UP)) == IFF_UP)
+			break;
+		dev = NULL;
+	}
+	if (dev)
+		dev_hold(dev);
+	spin_unlock_bh(&pndevs.lock);
+	return dev;
+}
+
+int phonet_address_add(struct net_device *dev, u8 addr)
+{
+	struct phonet_device *pnd;
+	int err = 0;
+
+	spin_lock_bh(&pndevs.lock);
+	/* Find or create Phonet-specific device data */
+	pnd = __phonet_get(dev);
+	if (pnd == NULL)
+		pnd = __phonet_device_alloc(dev);
+	if (unlikely(pnd == NULL))
+		err = -ENOMEM;
+	else if (test_and_set_bit(addr >> 2, pnd->addrs))
+		err = -EEXIST;
+	spin_unlock_bh(&pndevs.lock);
+	return err;
+}
+
+int phonet_address_del(struct net_device *dev, u8 addr)
+{
+	struct phonet_device *pnd;
+	int err = 0;
+
+	spin_lock_bh(&pndevs.lock);
+	pnd = __phonet_get(dev);
+	if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs))
+		err = -EADDRNOTAVAIL;
+	if (bitmap_empty(pnd->addrs, 64))
+		__phonet_device_free(pnd);
+	spin_unlock_bh(&pndevs.lock);
+	return err;
+}
+
+/* Gets a source address toward a destination, through a interface. */
+u8 phonet_address_get(struct net_device *dev, u8 addr)
+{
+	struct phonet_device *pnd;
+
+	spin_lock_bh(&pndevs.lock);
+	pnd = __phonet_get(dev);
+	if (pnd) {
+		BUG_ON(bitmap_empty(pnd->addrs, 64));
+
+		/* Use same source address as destination, if possible */
+		if (!test_bit(addr >> 2, pnd->addrs))
+			addr = find_first_bit(pnd->addrs, 64) << 2;
+	} else
+		addr = PN_NO_ADDR;
+	spin_unlock_bh(&pndevs.lock);
+	return addr;
+}
+
+int phonet_address_lookup(u8 addr)
+{
+	struct phonet_device *pnd;
+
+	spin_lock_bh(&pndevs.lock);
+	list_for_each_entry(pnd, &pndevs.list, list) {
+		/* Don't allow unregistering devices! */
+		if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
+				((pnd->netdev->flags & IFF_UP)) != IFF_UP)
+			continue;
+
+		if (test_bit(addr >> 2, pnd->addrs)) {
+			spin_unlock_bh(&pndevs.lock);
+			return 0;
+		}
+	}
+	spin_unlock_bh(&pndevs.lock);
+	return -EADDRNOTAVAIL;
+}
+
+/* notify Phonet of device events */
+static int phonet_device_notify(struct notifier_block *me, unsigned long what,
+				void *arg)
+{
+	struct net_device *dev = arg;
+
+	if (what == NETDEV_UNREGISTER) {
+		struct phonet_device *pnd;
+
+		/* Destroy phonet-specific device data */
+		spin_lock_bh(&pndevs.lock);
+		pnd = __phonet_get(dev);
+		if (pnd)
+			__phonet_device_free(pnd);
+		spin_unlock_bh(&pndevs.lock);
+	}
+	return 0;
+
+}
+
+static struct notifier_block phonet_device_notifier = {
+	.notifier_call = phonet_device_notify,
+	.priority = 0,
+};
+
+/* Initialize Phonet devices list */
+void phonet_device_init(void)
+{
+	register_netdevice_notifier(&phonet_device_notifier);
+}
+
+void phonet_device_exit(void)
+{
+	struct phonet_device *pnd, *n;
+
+	rtnl_unregister_all(PF_PHONET);
+	rtnl_lock();
+	spin_lock_bh(&pndevs.lock);
+
+	list_for_each_entry_safe(pnd, n, &pndevs.list, list)
+		__phonet_device_free(pnd);
+
+	spin_unlock_bh(&pndevs.lock);
+	rtnl_unlock();
+	unregister_netdevice_notifier(&phonet_device_notifier);
+}