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authorGuillaume Nault <g.nault@alphalink.fr>2016-04-28 17:55:30 +0200
committerDavid S. Miller <davem@davemloft.net>2016-04-29 16:09:44 -0400
commit96d934c70db6e1bc135600c57da1285eaf7efb26 (patch)
treeef01020246a3fbe5aa82f4d1460298e5008d28a0 /drivers/net/ppp/ppp_generic.c
parentppp: define reusable device creation functions (diff)
downloadlinux-dev-96d934c70db6e1bc135600c57da1285eaf7efb26.tar.xz
linux-dev-96d934c70db6e1bc135600c57da1285eaf7efb26.zip
ppp: add rtnetlink device creation support
Define PPP device handler for use with rtnetlink. The only PPP specific attribute is IFLA_PPP_DEV_FD. It is mandatory and contains the file descriptor of the associated /dev/ppp instance (the file descriptor which would have been used for ioctl(PPPIOCNEWUNIT) in the ioctl-based API). The PPP device is removed when this file descriptor is released (same behaviour as with ioctl based PPP devices). PPP devices created with the rtnetlink API behave like the ones created with ioctl(PPPIOCNEWUNIT). In particular existing ioctls work the same way, no matter how the PPP device was created. The rtnl callbacks are also assigned to ioctl based PPP devices. This way, rtnl messages have the same effect on any PPP devices. The immediate effect is that all PPP devices, even ioctl-based ones, can now be removed with "ip link del". A minor difference still exists between ioctl and rtnl based PPP interfaces: in the device name, the number following the "ppp" prefix corresponds to the PPP unit number for ioctl based devices, while it is just an unrelated incrementing index for rtnl ones. Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ppp/ppp_generic.c')
-rw-r--r--drivers/net/ppp/ppp_generic.c115
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");