1 files changed, 112 insertions, 3 deletions

diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index 59077c86ba0e..8dedafa1a95d 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -46,6 +46,7 @@
 #include <linux/device.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
+#include <linux/file.h>
 #include <asm/unaligned.h>
 #include <net/slhc_vj.h>
 #include <linux/atomic.h>
@@ -186,6 +187,7 @@ struct channel {
 struct ppp_config {
 	struct file *file;
 	s32 unit;
+	bool ifname_is_set;
 };
 
 /*
@@ -286,6 +288,7 @@ static int unit_get(struct idr *p, void *ptr);
 static int unit_set(struct idr *p, void *ptr, int n);
 static void unit_put(struct idr *p, int n);
 static void *unit_find(struct idr *p, int n);
+static void ppp_setup(struct net_device *dev);
 
 static const struct net_device_ops ppp_netdev_ops;
 
@@ -964,7 +967,7 @@ static struct pernet_operations ppp_net_ops = {
 	.size = sizeof(struct ppp_net),
 };
 
-static int ppp_unit_register(struct ppp *ppp, int unit)
+static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
 {
 	struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
 	int ret;
@@ -994,7 +997,8 @@ static int ppp_unit_register(struct ppp *ppp, int unit)
 	}
 	ppp->file.index = ret;
 
-	snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
+	if (!ifname_is_set)
+		snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
 
 	ret = register_netdevice(ppp->dev);
 	if (ret < 0)
@@ -1043,7 +1047,7 @@ static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
 	ppp->active_filter = NULL;
 #endif /* CONFIG_PPP_FILTER */
 
-	err = ppp_unit_register(ppp, conf->unit);
+	err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
 	if (err < 0)
 		return err;
 
@@ -1052,6 +1056,99 @@ static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
 	return 0;
 }
 
+static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
+	[IFLA_PPP_DEV_FD]	= { .type = NLA_S32 },
+};
+
+static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[])
+{
+	if (!data)
+		return -EINVAL;
+
+	if (!data[IFLA_PPP_DEV_FD])
+		return -EINVAL;
+	if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
+		return -EBADF;
+
+	return 0;
+}
+
+static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
+			  struct nlattr *tb[], struct nlattr *data[])
+{
+	struct ppp_config conf = {
+		.unit = -1,
+		.ifname_is_set = true,
+	};
+	struct file *file;
+	int err;
+
+	file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
+	if (!file)
+		return -EBADF;
+
+	/* rtnl_lock is already held here, but ppp_create_interface() locks
+	 * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
+	 * possible deadlock due to lock order inversion, at the cost of
+	 * pushing the problem back to userspace.
+	 */
+	if (!mutex_trylock(&ppp_mutex)) {
+		err = -EBUSY;
+		goto out;
+	}
+
+	if (file->f_op != &ppp_device_fops || file->private_data) {
+		err = -EBADF;
+		goto out_unlock;
+	}
+
+	conf.file = file;
+	err = ppp_dev_configure(src_net, dev, &conf);
+
+out_unlock:
+	mutex_unlock(&ppp_mutex);
+out:
+	fput(file);
+
+	return err;
+}
+
+static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
+{
+	unregister_netdevice_queue(dev, head);
+}
+
+static size_t ppp_nl_get_size(const struct net_device *dev)
+{
+	return 0;
+}
+
+static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
+{
+	return 0;
+}
+
+static struct net *ppp_nl_get_link_net(const struct net_device *dev)
+{
+	struct ppp *ppp = netdev_priv(dev);
+
+	return ppp->ppp_net;
+}
+
+static struct rtnl_link_ops ppp_link_ops __read_mostly = {
+	.kind		= "ppp",
+	.maxtype	= IFLA_PPP_MAX,
+	.policy		= ppp_nl_policy,
+	.priv_size	= sizeof(struct ppp),
+	.setup		= ppp_setup,
+	.validate	= ppp_nl_validate,
+	.newlink	= ppp_nl_newlink,
+	.dellink	= ppp_nl_dellink,
+	.get_size	= ppp_nl_get_size,
+	.fill_info	= ppp_nl_fill_info,
+	.get_link_net	= ppp_nl_get_link_net,
+};
+
 #define PPP_MAJOR	108
 
 /* Called at boot time if ppp is compiled into the kernel,
@@ -1080,11 +1177,19 @@ static int __init ppp_init(void)
 		goto out_chrdev;
 	}
 
+	err = rtnl_link_register(&ppp_link_ops);
+	if (err) {
+		pr_err("failed to register rtnetlink PPP handler\n");
+		goto out_class;
+	}
+
 	/* not a big deal if we fail here :-) */
 	device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
 
 	return 0;
 
+out_class:
+	class_destroy(ppp_class);
 out_chrdev:
 	unregister_chrdev(PPP_MAJOR, "ppp");
 out_net:
@@ -2829,6 +2934,7 @@ static int ppp_create_interface(struct net *net, struct file *file, int *unit)
 	struct ppp_config conf = {
 		.file = file,
 		.unit = *unit,
+		.ifname_is_set = false,
 	};
 	struct net_device *dev;
 	struct ppp *ppp;
@@ -2840,6 +2946,7 @@ static int ppp_create_interface(struct net *net, struct file *file, int *unit)
 		goto err;
 	}
 	dev_net_set(dev, net);
+	dev->rtnl_link_ops = &ppp_link_ops;
 
 	rtnl_lock();
 
@@ -3046,6 +3153,7 @@ static void __exit ppp_cleanup(void)
 	/* should never happen */
 	if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
 		pr_err("PPP: removing module but units remain!\n");
+	rtnl_link_unregister(&ppp_link_ops);
 	unregister_chrdev(PPP_MAJOR, "ppp");
 	device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
 	class_destroy(ppp_class);
@@ -3104,4 +3212,5 @@ EXPORT_SYMBOL(ppp_register_compressor);
 EXPORT_SYMBOL(ppp_unregister_compressor);
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
+MODULE_ALIAS_RTNL_LINK("ppp");
 MODULE_ALIAS("devname:ppp");