Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
net: Allow to specify ifindex when device is moved to another namespace
Currently, we can specify ifindex on link creation. This change allows
to specify ifindex when a device is moved to another network namespace.
Even now, a device ifindex can be changed if there is another device
with the same ifindex in the target namespace. So this change doesn't
introduce completely new behavior, it adds more control to the process.
CRIU users want to restore containers with pre-created network devices.
A user will provide network devices and instructions where they have to
be restored, then CRIU will restore network namespaces and move devices
into them. The problem is that devices have to be restored with the same
indexes that they have before C/R.
Cc: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>
Suggested-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
authored by
Andrei Vagin
and committed by
David S. Miller
eeb85a14
d3295869
+39
-17
+1
-1
drivers/net/hyperv/netvsc_drv.c
+1
-1
drivers/net/hyperv/netvsc_drv.c
···
2354
2354
*/
2355
2355
if (!net_eq(dev_net(ndev), dev_net(vf_netdev))) {
2356
2356
ret = dev_change_net_namespace(vf_netdev,
2357
-
dev_net(ndev), "eth%d");
2357
+
dev_net(ndev), "eth%d", 0);
2358
2358
if (ret)
2359
2359
netdev_err(vf_netdev,
2360
2360
"could not move to same namespace as %s: %d\n",
+2
-1
include/linux/netdevice.h
+2
-1
include/linux/netdevice.h
···
4026
4026
int dev_change_name(struct net_device *, const char *);
4027
4027
int dev_set_alias(struct net_device *, const char *, size_t);
4028
4028
int dev_get_alias(const struct net_device *, char *, size_t);
4029
-
int dev_change_net_namespace(struct net_device *, struct net *, const char *);
4029
+
int dev_change_net_namespace(struct net_device *dev, struct net *net,
4030
+
const char *pat, int new_ifindex);
4030
4031
int __dev_set_mtu(struct net_device *, int);
4031
4032
int dev_validate_mtu(struct net_device *dev, int mtu,
4032
4033
struct netlink_ext_ack *extack);
+17
-7
net/core/dev.c
+17
-7
net/core/dev.c
···
11067
11067
* @net: network namespace
11068
11068
* @pat: If not NULL name pattern to try if the current device name
11069
11069
* is already taken in the destination network namespace.
11070
+
* @new_ifindex: If not zero, specifies device index in the target
11071
+
* namespace.
11070
11072
*
11071
11073
* This function shuts down a device interface and moves it
11072
11074
* to a new network namespace. On success 0 is returned, on
···
11077
11075
* Callers must hold the rtnl semaphore.
11078
11076
*/
11079
11077
11080
-
int dev_change_net_namespace(struct net_device *dev, struct net *net, const char *pat)
11078
+
int dev_change_net_namespace(struct net_device *dev, struct net *net,
11079
+
const char *pat, int new_ifindex)
11081
11080
{
11082
11081
struct net *net_old = dev_net(dev);
11083
-
int err, new_nsid, new_ifindex;
11082
+
int err, new_nsid;
11084
11083
11085
11084
ASSERT_RTNL();
11086
11085
···
11112
11109
goto out;
11113
11110
}
11114
11111
11112
+
/* Check that new_ifindex isn't used yet. */
11113
+
err = -EBUSY;
11114
+
if (new_ifindex && __dev_get_by_index(net, new_ifindex))
11115
+
goto out;
11116
+
11115
11117
/*
11116
11118
* And now a mini version of register_netdevice unregister_netdevice.
11117
11119
*/
···
11144
11136
11145
11137
new_nsid = peernet2id_alloc(dev_net(dev), net, GFP_KERNEL);
11146
11138
/* If there is an ifindex conflict assign a new one */
11147
-
if (__dev_get_by_index(net, dev->ifindex))
11148
-
new_ifindex = dev_new_index(net);
11149
-
else
11150
-
new_ifindex = dev->ifindex;
11139
+
if (!new_ifindex) {
11140
+
if (__dev_get_by_index(net, dev->ifindex))
11141
+
new_ifindex = dev_new_index(net);
11142
+
else
11143
+
new_ifindex = dev->ifindex;
11144
+
}
11151
11145
11152
11146
rtmsg_ifinfo_newnet(RTM_DELLINK, dev, ~0U, GFP_KERNEL, &new_nsid,
11153
11147
new_ifindex);
···
11458
11448
snprintf(fb_name, IFNAMSIZ, "dev%d", dev->ifindex);
11459
11449
if (__dev_get_by_name(&init_net, fb_name))
11460
11450
snprintf(fb_name, IFNAMSIZ, "dev%%d");
11461
-
err = dev_change_net_namespace(dev, &init_net, fb_name);
11451
+
err = dev_change_net_namespace(dev, &init_net, fb_name, 0);
11462
11452
if (err) {
11463
11453
pr_emerg("%s: failed to move %s to init_net: %d\n",
11464
11454
__func__, dev->name, err);
+15
-4
net/core/rtnetlink.c
+15
-4
net/core/rtnetlink.c
···
2266
2266
return -EINVAL;
2267
2267
}
2268
2268
2269
+
if (tb[IFLA_NEW_IFINDEX] && nla_get_s32(tb[IFLA_NEW_IFINDEX]) <= 0)
2270
+
return -EINVAL;
2271
+
2269
2272
if (tb[IFLA_AF_SPEC]) {
2270
2273
struct nlattr *af;
2271
2274
int rem, err;
···
2606
2603
return err;
2607
2604
2608
2605
if (tb[IFLA_NET_NS_PID] || tb[IFLA_NET_NS_FD] || tb[IFLA_TARGET_NETNSID]) {
2609
-
struct net *net = rtnl_link_get_net_capable(skb, dev_net(dev),
2610
-
tb, CAP_NET_ADMIN);
2606
+
struct net *net;
2607
+
int new_ifindex;
2608
+
2609
+
net = rtnl_link_get_net_capable(skb, dev_net(dev),
2610
+
tb, CAP_NET_ADMIN);
2611
2611
if (IS_ERR(net)) {
2612
2612
err = PTR_ERR(net);
2613
2613
goto errout;
2614
2614
}
2615
2615
2616
-
err = dev_change_net_namespace(dev, net, ifname);
2616
+
if (tb[IFLA_NEW_IFINDEX])
2617
+
new_ifindex = nla_get_s32(tb[IFLA_NEW_IFINDEX]);
2618
+
else
2619
+
new_ifindex = 0;
2620
+
2621
+
err = dev_change_net_namespace(dev, net, ifname, new_ifindex);
2617
2622
put_net(net);
2618
2623
if (err)
2619
2624
goto errout;
···
3463
3452
if (err < 0)
3464
3453
goto out_unregister;
3465
3454
if (link_net) {
3466
-
err = dev_change_net_namespace(dev, dest_net, ifname);
3455
+
err = dev_change_net_namespace(dev, dest_net, ifname, 0);
3467
3456
if (err < 0)
3468
3457
goto out_unregister;
3469
3458
}
+2
-2
net/ieee802154/core.c
+2
-2
net/ieee802154/core.c
···
205
205
if (!wpan_dev->netdev)
206
206
continue;
207
207
wpan_dev->netdev->features &= ~NETIF_F_NETNS_LOCAL;
208
-
err = dev_change_net_namespace(wpan_dev->netdev, net, "wpan%d");
208
+
err = dev_change_net_namespace(wpan_dev->netdev, net, "wpan%d", 0);
209
209
if (err)
210
210
break;
211
211
wpan_dev->netdev->features |= NETIF_F_NETNS_LOCAL;
···
222
222
continue;
223
223
wpan_dev->netdev->features &= ~NETIF_F_NETNS_LOCAL;
224
224
err = dev_change_net_namespace(wpan_dev->netdev, net,
225
-
"wpan%d");
225
+
"wpan%d", 0);
226
226
WARN_ON(err);
227
227
wpan_dev->netdev->features |= NETIF_F_NETNS_LOCAL;
228
228
}
+2
-2
net/wireless/core.c
+2
-2
net/wireless/core.c
···
165
165
if (!wdev->netdev)
166
166
continue;
167
167
wdev->netdev->features &= ~NETIF_F_NETNS_LOCAL;
168
-
err = dev_change_net_namespace(wdev->netdev, net, "wlan%d");
168
+
err = dev_change_net_namespace(wdev->netdev, net, "wlan%d", 0);
169
169
if (err)
170
170
break;
171
171
wdev->netdev->features |= NETIF_F_NETNS_LOCAL;
···
182
182
continue;
183
183
wdev->netdev->features &= ~NETIF_F_NETNS_LOCAL;
184
184
err = dev_change_net_namespace(wdev->netdev, net,
185
-
"wlan%d");
185
+
"wlan%d", 0);
186
186
WARN_ON(err);
187
187
wdev->netdev->features |= NETIF_F_NETNS_LOCAL;
188
188
}