diff options
| author | Pavel Emelyanov <xemul@parallels.com> | 2013-08-21 14:31:38 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-08-21 12:21:45 -0700 |
| commit | fb7589a162162223e6bb6422dde3fb1ce07d9a78 (patch) | |
| tree | f99c3c7c9af2681f57b8b7beb4b859bf9d2bf4f5 | |
| parent | 5f1cd200c4e4e1a6bce946aaac40c7a10427f3ed (diff) | |
tun: Add ability to create tun device with given index
Tun devices cannot be created with ifidex user wants, but it's
required by checkpoint-restore project.
Long time ago such ability was implemented for rtnl_ops-based
interface for creating links (9c7dafbf net: Allow to create links
with given ifindex), but the only API for creating and managing
tuntap devices is ioctl-based and is evolving with adding new ones
(cde8b15f tuntap: add ioctl to attach or detach a file form tuntap
device).
Following that trend, here's how a new ioctl that sets the ifindex
for device, that _will_ be created by TUNSETIFF ioctl looks like.
So those who want a tuntap device with the ifindex N, should open
the tun device, call ioctl(fd, TUNSETIFINDEX, &N), then call TUNSETIFF.
If the index N is busy, then the register_netdev will find this out
and the ioctl would be failed with -EBUSY.
If setifindex is not called, then it will be generated as before.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/tun.c | 21 | ||||
| -rw-r--r-- | include/uapi/linux/if_tun.h | 1 |
2 files changed, 21 insertions, 1 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 7ed13cc0dcb2..4b65fbcc490f 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -138,7 +138,10 @@ struct tun_file { struct fasync_struct *fasync; /* only used for fasnyc */ unsigned int flags; - u16 queue_index; + union { + u16 queue_index; + unsigned int ifindex; + }; struct list_head next; struct tun_struct *detached; }; @@ -1601,6 +1604,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) dev_net_set(dev, net); dev->rtnl_link_ops = &tun_link_ops; + dev->ifindex = tfile->ifindex; tun = netdev_priv(dev); tun->dev = dev; @@ -1817,6 +1821,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, kgid_t group; int sndbuf; int vnet_hdr_sz; + unsigned int ifindex; int ret; if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { @@ -1851,6 +1856,19 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, ret = -EFAULT; goto unlock; } + if (cmd == TUNSETIFINDEX) { + ret = -EPERM; + if (tun) + goto unlock; + + ret = -EFAULT; + if (copy_from_user(&ifindex, argp, sizeof(ifindex))) + goto unlock; + + ret = 0; + tfile->ifindex = ifindex; + goto unlock; + } ret = -EBADFD; if (!tun) @@ -2099,6 +2117,7 @@ static int tun_chr_open(struct inode *inode, struct file * file) rcu_assign_pointer(tfile->tun, NULL); tfile->net = get_net(current->nsproxy->net_ns); tfile->flags = 0; + tfile->ifindex = 0; rcu_assign_pointer(tfile->socket.wq, &tfile->wq); init_waitqueue_head(&tfile->wq.wait); diff --git a/include/uapi/linux/if_tun.h b/include/uapi/linux/if_tun.h index 1870ee29bb37..c58d023c4822 100644 --- a/include/uapi/linux/if_tun.h +++ b/include/uapi/linux/if_tun.h @@ -56,6 +56,7 @@ #define TUNGETVNETHDRSZ _IOR('T', 215, int) #define TUNSETVNETHDRSZ _IOW('T', 216, int) #define TUNSETQUEUE _IOW('T', 217, int) +#define TUNSETIFINDEX _IOW('T', 218, unsigned int) /* TUNSETIFF ifr flags */ #define IFF_TUN 0x0001 |