sd-rtnl: rework rtnl type system

Use a static table with all the typing information, rather than repeated
switch statements. This should make it a lot simpler to add new types.

We need to keep all the type info to be able to create containers
without exposing their implementation details to the users of the library.

As a freebee we verify the types of appended/read attributes.

The API is extended to nicely deal with unions of container types.

1 files changed, 2 insertions, 14 deletions

diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
index 9a9ed9dc6e..84724d59c9 100644
--- a/src/nspawn/nspawn.c
+++ b/src/nspawn/nspawn.c
@@ -1486,13 +1486,7 @@ static int setup_veth(pid_t pid, char iface_name[IFNAMSIZ]) {
                 return r;
         }
 
-        r = sd_rtnl_message_append_string(m, IFLA_INFO_KIND, "veth");
-        if (r < 0) {
-                log_error("Failed to append netlink kind: %s", strerror(-r));
-                return r;
-        }
-
-        r = sd_rtnl_message_open_container(m, IFLA_INFO_DATA);
+        r = sd_rtnl_message_open_container_union(m, IFLA_INFO_DATA, "veth");
         if (r < 0) {
                 log_error("Failed to open netlink container: %s", strerror(-r));
                 return r;
@@ -1757,13 +1751,7 @@ static int setup_macvlan(pid_t pid) {
                         return r;
                 }
 
-                r = sd_rtnl_message_append_string(m, IFLA_INFO_KIND, "macvlan");
-                if (r < 0) {
-                        log_error("Failed to append netlink kind: %s", strerror(-r));
-                        return r;
-                }
-
-                r = sd_rtnl_message_open_container(m, IFLA_INFO_DATA);
+                r = sd_rtnl_message_open_container_union(m, IFLA_INFO_DATA, "macvlan");
                 if (r < 0) {
                         log_error("Failed to open netlink container: %s", strerror(-r));
                         return r;