net: rtnetlink: add linkprop commands to add and delete alternative ifnames

Add two commands to add and delete list of link properties. Implement
the first property type along - alternative ifnames.
Each net device can have multiple alternative names.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 103 insertions, 0 deletions

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 1ee6460f8275..e13646993d82 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1750,6 +1750,9 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
 	[IFLA_CARRIER_DOWN_COUNT] = { .type = NLA_U32 },
 	[IFLA_MIN_MTU]		= { .type = NLA_U32 },
 	[IFLA_MAX_MTU]		= { .type = NLA_U32 },
+	[IFLA_PROP_LIST]	= { .type = NLA_NESTED },
+	[IFLA_ALT_IFNAME]	= { .type = NLA_STRING,
+				    .len = ALTIFNAMSIZ - 1 },
 };
 
 static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
@@ -3373,6 +3376,103 @@ out:
 	return err;
 }
 
+static int rtnl_alt_ifname(int cmd, struct net_device *dev, struct nlattr *attr,
+			   bool *changed, struct netlink_ext_ack *extack)
+{
+	char *alt_ifname;
+	int err;
+
+	err = nla_validate(attr, attr->nla_len, IFLA_MAX, ifla_policy, extack);
+	if (err)
+		return err;
+
+	alt_ifname = nla_data(attr);
+	if (cmd == RTM_NEWLINKPROP) {
+		alt_ifname = kstrdup(alt_ifname, GFP_KERNEL);
+		if (!alt_ifname)
+			return -ENOMEM;
+		err = netdev_name_node_alt_create(dev, alt_ifname);
+		if (err) {
+			kfree(alt_ifname);
+			return err;
+		}
+	} else if (cmd == RTM_DELLINKPROP) {
+		err = netdev_name_node_alt_destroy(dev, alt_ifname);
+		if (err)
+			return err;
+	} else {
+		WARN_ON(1);
+		return 0;
+	}
+
+	*changed = true;
+	return 0;
+}
+
+static int rtnl_linkprop(int cmd, struct sk_buff *skb, struct nlmsghdr *nlh,
+			 struct netlink_ext_ack *extack)
+{
+	struct net *net = sock_net(skb->sk);
+	struct nlattr *tb[IFLA_MAX + 1];
+	struct net_device *dev;
+	struct ifinfomsg *ifm;
+	bool changed = false;
+	struct nlattr *attr;
+	int err, rem;
+
+	err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFLA_MAX, ifla_policy, extack);
+	if (err)
+		return err;
+
+	err = rtnl_ensure_unique_netns(tb, extack, true);
+	if (err)
+		return err;
+
+	ifm = nlmsg_data(nlh);
+	if (ifm->ifi_index > 0) {
+		dev = __dev_get_by_index(net, ifm->ifi_index);
+	} else if (tb[IFLA_IFNAME]) {
+		char ifname[IFNAMSIZ];
+
+		nla_strlcpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
+		dev = __dev_get_by_name(net, ifname);
+	} else {
+		return -EINVAL;
+	}
+
+	if (!dev)
+		return -ENODEV;
+
+	if (!tb[IFLA_PROP_LIST])
+		return 0;
+
+	nla_for_each_nested(attr, tb[IFLA_PROP_LIST], rem) {
+		switch (nla_type(attr)) {
+		case IFLA_ALT_IFNAME:
+			err = rtnl_alt_ifname(cmd, dev, attr, &changed, extack);
+			if (err)
+				return err;
+			break;
+		}
+	}
+
+	if (changed)
+		netdev_state_change(dev);
+	return 0;
+}
+
+static int rtnl_newlinkprop(struct sk_buff *skb, struct nlmsghdr *nlh,
+			    struct netlink_ext_ack *extack)
+{
+	return rtnl_linkprop(RTM_NEWLINKPROP, skb, nlh, extack);
+}
+
+static int rtnl_dellinkprop(struct sk_buff *skb, struct nlmsghdr *nlh,
+			    struct netlink_ext_ack *extack)
+{
+	return rtnl_linkprop(RTM_DELLINKPROP, skb, nlh, extack);
+}
+
 static u16 rtnl_calcit(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
 	struct net *net = sock_net(skb->sk);
@@ -5331,6 +5431,9 @@ void __init rtnetlink_init(void)
 	rtnl_register(PF_UNSPEC, RTM_GETROUTE, NULL, rtnl_dump_all, 0);
 	rtnl_register(PF_UNSPEC, RTM_GETNETCONF, NULL, rtnl_dump_all, 0);
 
+	rtnl_register(PF_UNSPEC, RTM_NEWLINKPROP, rtnl_newlinkprop, NULL, 0);
+	rtnl_register(PF_UNSPEC, RTM_DELLINKPROP, rtnl_dellinkprop, NULL, 0);
+
 	rtnl_register(PF_BRIDGE, RTM_NEWNEIGH, rtnl_fdb_add, NULL, 0);
 	rtnl_register(PF_BRIDGE, RTM_DELNEIGH, rtnl_fdb_del, NULL, 0);
 	rtnl_register(PF_BRIDGE, RTM_GETNEIGH, rtnl_fdb_get, rtnl_fdb_dump, 0);