[PATCH 8/9] ipv6: streamline addrconf_set_dstaddr

From: Christoph Hellwig
Date: Tue May 19 2020 - 09:04:31 EST


Factor out a addrconf_set_sit_dstaddr helper for the actual work if we
found a SIT device, and only hold the rtnl lock around the device lookup
and that new helper, as there is no point in holding it over a
copy_from_user call.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
net/ipv6/addrconf.c | 87 ++++++++++++++++++++-------------------------
1 file changed, 38 insertions(+), 49 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 8300176f91e74..c827edf877414 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2783,6 +2783,38 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
in6_dev_put(in6_dev);
}

+static int addrconf_set_sit_dstaddr(struct net *net, struct net_device *dev,
+ struct in6_ifreq *ireq)
+{
+ struct ip_tunnel_parm p = { };
+ mm_segment_t oldfs = get_fs();
+ struct ifreq ifr;
+ int err;
+
+ if (!(ipv6_addr_type(&ireq->ifr6_addr) & IPV6_ADDR_COMPATv4))
+ return -EADDRNOTAVAIL;
+
+ p.iph.daddr = ireq->ifr6_addr.s6_addr32[3];
+ p.iph.version = 4;
+ p.iph.ihl = 5;
+ p.iph.protocol = IPPROTO_IPV6;
+ p.iph.ttl = 64;
+ ifr.ifr_ifru.ifru_data = (__force void __user *)&p;
+
+ if (!dev->netdev_ops->ndo_do_ioctl)
+ return -EOPNOTSUPP;
+ set_fs(KERNEL_DS);
+ err = dev->netdev_ops->ndo_do_ioctl(dev, &ifr, SIOCADDTUNNEL);
+ set_fs(oldfs);
+ if (err)
+ return err;
+
+ dev = __dev_get_by_name(net, p.name);
+ if (!dev)
+ return -ENOBUFS;
+ return dev_open(dev, NULL);
+}
+
/*
* Set destination address.
* Special case for SIT interfaces where we create a new "virtual"
@@ -2790,62 +2822,19 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
*/
int addrconf_set_dstaddr(struct net *net, void __user *arg)
{
- struct in6_ifreq ireq;
struct net_device *dev;
- int err = -EINVAL;
+ struct in6_ifreq ireq;
+ int err = -ENODEV;

if (!IS_ENABLED(CONFIG_IPV6_SIT))
return -ENODEV;
-
- rtnl_lock();
-
- err = -EFAULT;
if (copy_from_user(&ireq, arg, sizeof(struct in6_ifreq)))
- goto err_exit;
+ return -EFAULT;

+ rtnl_lock();
dev = __dev_get_by_index(net, ireq.ifr6_ifindex);
-
- err = -ENODEV;
- if (!dev)
- goto err_exit;
-
- if (dev->type == ARPHRD_SIT) {
- const struct net_device_ops *ops = dev->netdev_ops;
- struct ifreq ifr;
- struct ip_tunnel_parm p;
-
- err = -EADDRNOTAVAIL;
- if (!(ipv6_addr_type(&ireq.ifr6_addr) & IPV6_ADDR_COMPATv4))
- goto err_exit;
-
- memset(&p, 0, sizeof(p));
- p.iph.daddr = ireq.ifr6_addr.s6_addr32[3];
- p.iph.saddr = 0;
- p.iph.version = 4;
- p.iph.ihl = 5;
- p.iph.protocol = IPPROTO_IPV6;
- p.iph.ttl = 64;
- ifr.ifr_ifru.ifru_data = (__force void __user *)&p;
-
- if (ops->ndo_do_ioctl) {
- mm_segment_t oldfs = get_fs();
-
- set_fs(KERNEL_DS);
- err = ops->ndo_do_ioctl(dev, &ifr, SIOCADDTUNNEL);
- set_fs(oldfs);
- } else
- err = -EOPNOTSUPP;
-
- if (err == 0) {
- err = -ENOBUFS;
- dev = __dev_get_by_name(net, p.name);
- if (!dev)
- goto err_exit;
- err = dev_open(dev, NULL);
- }
- }
-
-err_exit:
+ if (dev && dev->type == ARPHRD_SIT)
+ err = addrconf_set_sit_dstaddr(net, dev, &ireq);
rtnl_unlock();
return err;
}
--
2.26.2