net: Support specifying the network namespace upon device creation.

There is no good reason to not support userspace specifying the
network namespace during device creation, and it makes it easier
to create a network device and pass it to a child network namespace
with a well known name.

We have to be careful to ensure that the target network namespace
for the new device exists through the life of the call.  To keep
that logic clear I have factored out the network namespace grabbing
logic into rtnl_link_get_net.

In addtion we need to continue to pass the source network namespace
to the rtnl_link_ops.newlink method so that we can find the base
device source network namespace.

Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>

diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
index c3db111d2ff5d60f574fc15f343c5583a32ec5d5..5fe34d64ca2addecc3e1e01ff8c4cb051d330888 100644 (file)
--- a/drivers/net/can/dev.c
+++ b/drivers/net/can/dev.c
@@ -674,7 +674,7 @@ nla_put_failure:
        return -EMSGSIZE;
 }
 
-static int can_newlink(struct net_device *dev,
+static int can_newlink(struct net *src_net, struct net_device *dev,
                       struct nlattr *tb[], struct nlattr *data[])
 {
        return -EOPNOTSUPP;

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 20b7707f38efdee11dd339bab0117a740c32fe55..d7dba3f6f7637f510b8c6ba371def08697af19aa 100644 (file)
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -504,7 +504,7 @@ static int macvlan_get_tx_queues(struct net *net,
        return 0;
 }
 
-static int macvlan_newlink(struct net_device *dev,
+static int macvlan_newlink(struct net *src_net, struct net_device *dev,
                           struct nlattr *tb[], struct nlattr *data[])
 {
        struct macvlan_dev *vlan = netdev_priv(dev);
@@ -515,7 +515,7 @@ static int macvlan_newlink(struct net_device *dev,
        if (!tb[IFLA_LINK])
                return -EINVAL;
 
-       lowerdev = __dev_get_by_index(dev_net(dev), nla_get_u32(tb[IFLA_LINK]));
+       lowerdev = __dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
        if (lowerdev == NULL)
                return -ENODEV;
 

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 9bed694cd215a4d644952978e20172ae3bdc8175..2d657f2314cbdd2db4fb0243d82181c93358cca7 100644 (file)
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -340,7 +340,7 @@ static int veth_validate(struct nlattr *tb[], struct nlattr *data[])
 
 static struct rtnl_link_ops veth_link_ops;
 
-static int veth_newlink(struct net_device *dev,
+static int veth_newlink(struct net *src_net, struct net_device *dev,
                         struct nlattr *tb[], struct nlattr *data[])
 {
        int err;
@@ -348,6 +348,7 @@ static int veth_newlink(struct net_device *dev,
        struct veth_priv *priv;
        char ifname[IFNAMSIZ];
        struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
+       struct net *net;
 
        /*
         * create and register peer first
@@ -380,14 +381,22 @@ static int veth_newlink(struct net_device *dev,
        else
                snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
 
-       peer = rtnl_create_link(dev_net(dev), ifname, &veth_link_ops, tbp);
-       if (IS_ERR(peer))
+       net = rtnl_link_get_net(src_net, tbp);
+       if (IS_ERR(net))
+               return PTR_ERR(net);
+
+       peer = rtnl_create_link(src_net, net, ifname, &veth_link_ops, tbp);
+       if (IS_ERR(peer)) {
+               put_net(net);
                return PTR_ERR(peer);
+       }
 
        if (tbp[IFLA_ADDRESS] == NULL)
                random_ether_addr(peer->dev_addr);
 
        err = register_netdevice(peer);
+       put_net(net);
+       net = NULL;
        if (err < 0)
                goto err_register_peer;
 

diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h
index cd5af1f508f29ab34e4ba040862bb262ecd55fbe..48d3efcb0880ac256de3a56c8ac01f087481d1e4 100644 (file)
--- a/include/net/rtnetlink.h
+++ b/include/net/rtnetlink.h
@@ -55,7 +55,8 @@ struct rtnl_link_ops {
        int                     (*validate)(struct nlattr *tb[],
                                            struct nlattr *data[]);
 
-       int                     (*newlink)(struct net_device *dev,
+       int                     (*newlink)(struct net *src_net,
+                                          struct net_device *dev,
                                           struct nlattr *tb[],
                                           struct nlattr *data[]);
        int                     (*changelink)(struct net_device *dev,
@@ -83,8 +84,9 @@ extern void   rtnl_kill_links(struct net *net, struct rtnl_link_ops *ops);
 extern int     rtnl_link_register(struct rtnl_link_ops *ops);
 extern void    rtnl_link_unregister(struct rtnl_link_ops *ops);
 
-extern struct net_device *rtnl_create_link(struct net *net, char *ifname,
-               const struct rtnl_link_ops *ops, struct nlattr *tb[]);
+extern struct net *rtnl_link_get_net(struct net *src_net, struct nlattr *tb[]);
+extern struct net_device *rtnl_create_link(struct net *src_net, struct net *net,
+       char *ifname, const struct rtnl_link_ops *ops, struct nlattr *tb[]);
 extern const struct nla_policy ifla_policy[IFLA_MAX+1];
 
 #define MODULE_ALIAS_RTNL_LINK(kind) MODULE_ALIAS("rtnl-link-" kind)

diff --git a/net/8021q/vlan_netlink.c b/net/8021q/vlan_netlink.c
index a91504850195ff91ef178a390492fd50375e25c3..3c9cf6a8e7fbc9ca710cc39426fc235ca4b77a87 100644 (file)
--- a/net/8021q/vlan_netlink.c
+++ b/net/8021q/vlan_netlink.c
@@ -119,7 +119,7 @@ static int vlan_get_tx_queues(struct net *net,
        return 0;
 }
 
-static int vlan_newlink(struct net_device *dev,
+static int vlan_newlink(struct net *src_net, struct net_device *dev,
                        struct nlattr *tb[], struct nlattr *data[])
 {
        struct vlan_dev_info *vlan = vlan_dev_info(dev);
@@ -131,7 +131,7 @@ static int vlan_newlink(struct net_device *dev,
 
        if (!tb[IFLA_LINK])
                return -EINVAL;
-       real_dev = __dev_get_by_index(dev_net(dev), nla_get_u32(tb[IFLA_LINK]));
+       real_dev = __dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
        if (!real_dev)
                return -ENODEV;
 

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index e2f3317f290f95b171ee64da160f1b3d3079f817..33148a568199c7215b87e63f68a39b4a02afb4cd 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -733,6 +733,20 @@ static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
        [IFLA_INFO_DATA]        = { .type = NLA_NESTED },
 };
 
+struct net *rtnl_link_get_net(struct net *src_net, struct nlattr *tb[])
+{
+       struct net *net;
+       /* Examine the link attributes and figure out which
+        * network namespace we are talking about.
+        */
+       if (tb[IFLA_NET_NS_PID])
+               net = get_net_ns_by_pid(nla_get_u32(tb[IFLA_NET_NS_PID]));
+       else
+               net = get_net(src_net);
+       return net;
+}
+EXPORT_SYMBOL(rtnl_link_get_net);
+
 static int validate_linkmsg(struct net_device *dev, struct nlattr *tb[])
 {
        if (dev) {
@@ -756,8 +770,7 @@ static int do_setlink(struct net_device *dev, struct ifinfomsg *ifm,
        int err;
 
        if (tb[IFLA_NET_NS_PID]) {
-               struct net *net;
-               net = get_net_ns_by_pid(nla_get_u32(tb[IFLA_NET_NS_PID]));
+               struct net *net = rtnl_link_get_net(dev_net(dev), tb);
                if (IS_ERR(net)) {
                        err = PTR_ERR(net);
                        goto errout;
@@ -976,8 +989,8 @@ static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
        return 0;
 }
 
-struct net_device *rtnl_create_link(struct net *net, char *ifname,
-               const struct rtnl_link_ops *ops, struct nlattr *tb[])
+struct net_device *rtnl_create_link(struct net *src_net, struct net *net,
+       char *ifname, const struct rtnl_link_ops *ops, struct nlattr *tb[])
 {
        int err;
        struct net_device *dev;
@@ -985,7 +998,7 @@ struct net_device *rtnl_create_link(struct net *net, char *ifname,
        unsigned int real_num_queues = 1;
 
        if (ops->get_tx_queues) {
-               err = ops->get_tx_queues(net, tb, &num_queues,
+               err = ops->get_tx_queues(src_net, tb, &num_queues,
                                         &real_num_queues);
                if (err)
                        goto err;
@@ -995,16 +1008,16 @@ struct net_device *rtnl_create_link(struct net *net, char *ifname,
        if (!dev)
                goto err;
 
+       dev_net_set(dev, net);
+       dev->rtnl_link_ops = ops;
        dev->real_num_tx_queues = real_num_queues;
+
        if (strchr(dev->name, '%')) {
                err = dev_alloc_name(dev, dev->name);
                if (err < 0)
                        goto err_free;
        }
 
-       dev_net_set(dev, net);
-       dev->rtnl_link_ops = ops;
-
        if (tb[IFLA_MTU])
                dev->mtu = nla_get_u32(tb[IFLA_MTU]);
        if (tb[IFLA_ADDRESS])
@@ -1083,6 +1096,7 @@ replay:
 
        if (1) {
                struct nlattr *attr[ops ? ops->maxtype + 1 : 0], **data = NULL;
+               struct net *dest_net;
 
                if (ops) {
                        if (ops->maxtype && linkinfo[IFLA_INFO_DATA]) {
@@ -1147,17 +1161,19 @@ replay:
                if (!ifname[0])
                        snprintf(ifname, IFNAMSIZ, "%s%%d", ops->kind);
 
-               dev = rtnl_create_link(net, ifname, ops, tb);
+               dest_net = rtnl_link_get_net(net, tb);
+               dev = rtnl_create_link(net, dest_net, ifname, ops, tb);
 
                if (IS_ERR(dev))
                        err = PTR_ERR(dev);
                else if (ops->newlink)
-                       err = ops->newlink(dev, tb, data);
+                       err = ops->newlink(net, dev, tb, data);
                else
                        err = register_netdevice(dev);
-
                if (err < 0 && !IS_ERR(dev))
                        free_netdev(dev);
+
+               put_net(dest_net);
                return err;
        }
 }

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 71a3242fb7d00f9ccf83e3ab4475477311c96e24..a7de9e3a8f1860b7ffc982ada513cfa8fa705b5c 100644 (file)
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -1483,7 +1483,7 @@ static void ipgre_tap_setup(struct net_device *dev)
        dev->features           |= NETIF_F_NETNS_LOCAL;
 }
 
-static int ipgre_newlink(struct net_device *dev, struct nlattr *tb[],
+static int ipgre_newlink(struct net *src_net, struct net_device *dev, struct nlattr *tb[],
                         struct nlattr *data[])
 {
        struct ip_tunnel *nt;