[PATCH net-next v3 2/2] net: plumb extack in __dev_change_net_namespace()
From: Nicolas Dichtel <hidden>
Date: 2025-02-20 13:03:38
Subsystem:
networking drivers, networking [general], the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
It could be hard to understand why the netlink command fails. For example, if dev->netns_local is set, the error is "Invalid argument". Signed-off-by: Nicolas Dichtel <redacted> --- include/linux/netdevice.h | 5 +++-- net/core/dev.c | 41 +++++++++++++++++++++++++++++++-------- net/core/rtnetlink.c | 2 +- 3 files changed, 37 insertions(+), 11 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index fccc03cd2164..58d9f052f154 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h@@ -4155,12 +4155,13 @@ int dev_change_flags(struct net_device *dev, unsigned int flags, int dev_set_alias(struct net_device *, const char *, size_t); int dev_get_alias(const struct net_device *, char *, size_t); int __dev_change_net_namespace(struct net_device *dev, struct net *net, - const char *pat, int new_ifindex); + const char *pat, int new_ifindex, + struct netlink_ext_ack *extack); static inline int dev_change_net_namespace(struct net_device *dev, struct net *net, const char *pat) { - return __dev_change_net_namespace(dev, net, pat, 0); + return __dev_change_net_namespace(dev, net, pat, 0, NULL); } int __dev_set_mtu(struct net_device *, int); int dev_set_mtu(struct net_device *, int);
diff --git a/net/core/dev.c b/net/core/dev.c
index ebc000b56828..9605fa2e7415 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -11917,6 +11917,7 @@ EXPORT_SYMBOL(unregister_netdev); * is already taken in the destination network namespace. * @new_ifindex: If not zero, specifies device index in the target * namespace. + * @extack: netlink extended ack * * This function shuts down a device interface and moves it * to a new network namespace. On success 0 is returned, on
@@ -11926,7 +11927,8 @@ EXPORT_SYMBOL(unregister_netdev); */ int __dev_change_net_namespace(struct net_device *dev, struct net *net, - const char *pat, int new_ifindex) + const char *pat, int new_ifindex, + struct netlink_ext_ack *extack) { struct netdev_name_node *name_node; struct net *net_old = dev_net(dev);
@@ -11937,12 +11939,17 @@ int __dev_change_net_namespace(struct net_device *dev, struct net *net, /* Don't allow namespace local devices to be moved. */ err = -EINVAL; - if (dev->netns_local) + if (dev->netns_local) { + NL_SET_ERR_MSG(extack, + "The interface has the 'netns local' property"); goto out; + } /* Ensure the device has been registered */ - if (dev->reg_state != NETREG_REGISTERED) + if (dev->reg_state != NETREG_REGISTERED) { + NL_SET_ERR_MSG(extack, "The interface isn't registered"); goto out; + } /* Get out if there is nothing todo */ err = 0;
@@ -11955,30 +11962,48 @@ int __dev_change_net_namespace(struct net_device *dev, struct net *net, err = -EEXIST; if (netdev_name_in_use(net, dev->name)) { /* We get here if we can't use the current device name */ - if (!pat) + if (!pat) { + NL_SET_ERR_MSG(extack, + "An interface with the same name exists in the target netns"); goto out; + } err = dev_prep_valid_name(net, dev, pat, new_name, EEXIST); - if (err < 0) + if (err < 0) { + NL_SET_ERR_MSG_FMT(extack, + "Unable to use '%s' for the new interface name", + pat); goto out; + } } /* Check that none of the altnames conflicts. */ err = -EEXIST; netdev_for_each_altname(dev, name_node) - if (netdev_name_in_use(net, name_node->name)) + if (netdev_name_in_use(net, name_node->name)) { + NL_SET_ERR_MSG_FMT(extack, + "An interface with the altname %s exists in the target netns", + name_node->name); goto out; + } /* Check that new_ifindex isn't used yet. */ if (new_ifindex) { err = dev_index_reserve(net, new_ifindex); - if (err < 0) + if (err < 0) { + NL_SET_ERR_MSG_FMT(extack, + "The ifindex %d is not available in the target netns", + new_ifindex); goto out; + } } else { /* If there is an ifindex conflict assign a new one */ err = dev_index_reserve(net, dev->ifindex); if (err == -EBUSY) err = dev_index_reserve(net, 0); - if (err < 0) + if (err < 0) { + NL_SET_ERR_MSG(extack, + "Unable to allocate a new ifindex in the target netns"); goto out; + } new_ifindex = err; }
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index acf787e4d22d..717f2e3e333e 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c@@ -3028,7 +3028,7 @@ static int do_setlink(const struct sk_buff *skb, struct net_device *dev, new_ifindex = nla_get_s32_default(tb[IFLA_NEW_IFINDEX], 0); - err = __dev_change_net_namespace(dev, tgt_net, pat, new_ifindex); + err = __dev_change_net_namespace(dev, tgt_net, pat, new_ifindex, extack); if (err) goto errout;
--
2.47.1