From cde8b15f1aabe327038ee4e0e11dd6b798572f69 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Wed, 31 Oct 2012 19:46:01 +0000 Subject: [PATCH] tuntap: add ioctl to attach or detach a file form tuntap device Sometimes usespace may need to active/deactive a queue, this could be done by detaching and attaching a file from tuntap device. This patch introduces a new ioctls - TUNSETQUEUE which could be used to do this. Flag IFF_ATTACH_QUEUE were introduced to do attaching while IFF_DETACH_QUEUE were introduced to do the detaching. Signed-off-by: Jason Wang Signed-off-by: David S. Miller --- drivers/net/tun.c | 56 +++++++++++++++++++++++++++++++------ include/uapi/linux/if_tun.h | 3 ++ 2 files changed, 51 insertions(+), 8 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 2762c55aeb66..79b6f9ecc12c 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -195,6 +195,15 @@ static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb) return txq; } +static inline bool tun_not_capable(struct tun_struct *tun) +{ + const struct cred *cred = current_cred(); + + return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || + (gid_valid(tun->group) && !in_egroup_p(tun->group))) && + !capable(CAP_NET_ADMIN); +} + static void tun_set_real_num_queues(struct tun_struct *tun) { netif_set_real_num_tx_queues(tun->dev, tun->numqueues); @@ -1310,8 +1319,6 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) dev = __dev_get_by_name(net, ifr->ifr_name); if (dev) { - const struct cred *cred = current_cred(); - if (ifr->ifr_flags & IFF_TUN_EXCL) return -EBUSY; if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops) @@ -1321,9 +1328,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) else return -EINVAL; - if (((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || - (gid_valid(tun->group) && !in_egroup_p(tun->group))) && - !capable(CAP_NET_ADMIN)) + if (tun_not_capable(tun)) return -EPERM; err = security_tun_dev_attach(tfile->socket.sk); if (err < 0) @@ -1530,6 +1535,40 @@ static void tun_set_sndbuf(struct tun_struct *tun) } } +static int tun_set_queue(struct file *file, struct ifreq *ifr) +{ + struct tun_file *tfile = file->private_data; + struct tun_struct *tun; + struct net_device *dev; + int ret = 0; + + rtnl_lock(); + + if (ifr->ifr_flags & IFF_ATTACH_QUEUE) { + dev = __dev_get_by_name(tfile->net, ifr->ifr_name); + if (!dev) { + ret = -EINVAL; + goto unlock; + } + + tun = netdev_priv(dev); + if (dev->netdev_ops != &tap_netdev_ops && + dev->netdev_ops != &tun_netdev_ops) + ret = -EINVAL; + else if (tun_not_capable(tun)) + ret = -EPERM; + else + ret = tun_attach(tun, file); + } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) + __tun_detach(tfile, false); + else + ret = -EINVAL; + +unlock: + rtnl_unlock(); + return ret; +} + static long __tun_chr_ioctl(struct file *file, unsigned int cmd, unsigned long arg, int ifreq_len) { @@ -1543,7 +1582,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, int vnet_hdr_sz; int ret; - if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) { + if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { if (copy_from_user(&ifr, argp, ifreq_len)) return -EFAULT; } else { @@ -1554,9 +1593,10 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, * This is needed because we never checked for invalid flags on * TUNSETIFF. */ return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | - IFF_VNET_HDR, + IFF_VNET_HDR | IFF_MULTI_QUEUE, (unsigned int __user*)argp); - } + } else if (cmd == TUNSETQUEUE) + return tun_set_queue(file, &ifr); ret = 0; rtnl_lock(); diff --git a/include/uapi/linux/if_tun.h b/include/uapi/linux/if_tun.h index 8ef3a87b58a0..958497ad5bb5 100644 --- a/include/uapi/linux/if_tun.h +++ b/include/uapi/linux/if_tun.h @@ -54,6 +54,7 @@ #define TUNDETACHFILTER _IOW('T', 214, struct sock_fprog) #define TUNGETVNETHDRSZ _IOR('T', 215, int) #define TUNSETVNETHDRSZ _IOW('T', 216, int) +#define TUNSETQUEUE _IOW('T', 217, int) /* TUNSETIFF ifr flags */ #define IFF_TUN 0x0001 @@ -63,6 +64,8 @@ #define IFF_VNET_HDR 0x4000 #define IFF_TUN_EXCL 0x8000 #define IFF_MULTI_QUEUE 0x0100 +#define IFF_ATTACH_QUEUE 0x0200 +#define IFF_DETACH_QUEUE 0x0400 /* Features for GSO (TUNSETOFFLOAD). */ #define TUN_F_CSUM 0x01 /* You can hand me unchecksummed packets. */ -- 2.39.5