[patch net-next 4/7] net: rtnetlink: put alternative names to getlink message

[Jiri Pirko]

From: Jiri Pirko <j...@mellanox.com>

Extend exiting getlink info message with list of properties. Now the
only ones are alternative names.

Signed-off-by: Jiri Pirko <j...@mellanox.com>
---
rfc->v1:
- move size initialization after early return in
  rtnl_alt_ifname_list_size()/rtnl_prop_list_size()
- converted to generic property list
---
 net/core/rtnetlink.c | 53 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index e13646993d82..c38917371b84 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -980,6 +980,19 @@ static size_t rtnl_xdp_size(void)
        return xdp_size;
 }
 
+static size_t rtnl_prop_list_size(const struct net_device *dev)
+{
+       struct netdev_name_node *name_node;
+       size_t size;
+
+       if (list_empty(&dev->name_node->list))
+               return 0;
+       size = nla_total_size(0);
+       list_for_each_entry(name_node, &dev->name_node->list, list)
+               size += nla_total_size(ALTIFNAMSIZ);
+       return size;
+}
+
 static noinline size_t if_nlmsg_size(const struct net_device *dev,
                                     u32 ext_filter_mask)
 {
@@ -1027,6 +1040,7 @@ static noinline size_t if_nlmsg_size(const struct 
net_device *dev,
               + nla_total_size(4)  /* IFLA_CARRIER_DOWN_COUNT */
               + nla_total_size(4)  /* IFLA_MIN_MTU */
               + nla_total_size(4)  /* IFLA_MAX_MTU */
+              + rtnl_prop_list_size(dev)
               + 0;
 }
 
@@ -1584,6 +1598,42 @@ static int rtnl_fill_link_af(struct sk_buff *skb,
        return 0;
 }
 
+static int rtnl_fill_alt_ifnames(struct sk_buff *skb,
+                                const struct net_device *dev)
+{
+       struct netdev_name_node *name_node;
+       int count = 0;
+
+       list_for_each_entry(name_node, &dev->name_node->list, list) {
+               if (nla_put_string(skb, IFLA_ALT_IFNAME, name_node->name))
+                       return -EMSGSIZE;
+               count++;
+       }
+       return count;
+}
+
+static int rtnl_fill_prop_list(struct sk_buff *skb,
+                              const struct net_device *dev)
+{
+       struct nlattr *prop_list;
+       int ret;
+
+       prop_list = nla_nest_start(skb, IFLA_PROP_LIST);
+       if (!prop_list)
+               return -EMSGSIZE;
+
+       ret = rtnl_fill_alt_ifnames(skb, dev);
+       if (ret <= 0)
+               goto nest_cancel;
+
+       nla_nest_end(skb, prop_list);
+       return 0;
+
+nest_cancel:
+       nla_nest_cancel(skb, prop_list);
+       return ret;
+}
+
 static int rtnl_fill_ifinfo(struct sk_buff *skb,
                            struct net_device *dev, struct net *src_net,
                            int type, u32 pid, u32 seq, u32 change,
@@ -1697,6 +1747,9 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb,
                goto nla_put_failure_rcu;
        rcu_read_unlock();
 
+       if (rtnl_fill_prop_list(skb, dev))
+               goto nla_put_failure;
+
        nlmsg_end(skb, nlh);
        return 0;
 
-- 
2.21.0