iplink: enable to specify index when changing netns

When an interface is moved to another netns, it's possible to specify a
new ifindex. Let's add this support.

Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=eeb85a14ee34
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David Ahern <dsahern@kernel.org>

diff --git a/ip/iplink.c b/ip/iplink.c
index 2fc0443ca587e241b0e3c6a3a2b298a10e91d5dd..4e74512e01d298804cfc5de0b7956aacdb55dda4 100644 (file)
--- a/ip/iplink.c
+++ b/ip/iplink.c
@@ -579,6 +579,7 @@ static int iplink_parse_vf(int vf, int *argcp, char ***argvp,
 
 int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type)
 {
+       bool move_netns = false;
        char *name = NULL;
        char *dev = NULL;
        char *link = NULL;
@@ -684,6 +685,7 @@ int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type)
                                          IFLA_NET_NS_PID, &netns, 4);
                        else
                                invarg("Invalid \"netns\" value\n", *argv);
+                       move_netns = true;
                } else if (strcmp(*argv, "multicast") == 0) {
                        NEXT_ARG();
                        req->i.ifi_change |= IFF_MULTICAST;
@@ -981,9 +983,11 @@ int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type)
                }
        }
 
-       if (!(req->n.nlmsg_flags & NLM_F_CREATE) && index) {
+       if (index &&
+           (!(req->n.nlmsg_flags & NLM_F_CREATE) &&
+            !move_netns)) {
                fprintf(stderr,
-                       "index can be used only when creating devices.\n");
+                       "index can be used only when creating devices or when moving device to another netns.\n");
                exit(-1);
        }
 
@@ -1020,6 +1024,9 @@ int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type)
                /* Not renaming to the same name */
                if (name == dev)
                        name = NULL;
+
+               if (index)
+                       addattr32(&req->n, sizeof(*req), IFLA_NEW_IFINDEX, index);
        } else {
                if (name != dev) {
                        fprintf(stderr,