netns: enable to specify a nsid for a get request

Combined with NETNSA_TARGET_NSID, it enables to "translate" a nsid from one netns to a nsid of another netns. This is useful when using NETLINK_F_LISTEN_ALL_NSID because it helps the user to interpret a nsid received from an other netns. Signed-off-by: Nicolas Dichtel <[email protected]> Reviewed-by: David Ahern <[email protected]> Signed-off-by: David S. Miller <[email protected]>
penberg · Nov 28, 2018 · 3a4f68b · 3a4f68b
1 parent cff478b
commit 3a4f68b
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
@@ -797,6 +797,11 @@ static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh,
 	} else if (tb[NETNSA_FD]) {
 		peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD]));
 		nla = tb[NETNSA_FD];
+	} else if (tb[NETNSA_NSID]) {
+		peer = get_net_ns_by_id(net, nla_get_u32(tb[NETNSA_NSID]));
+		if (!peer)
+			peer = ERR_PTR(-ENOENT);
+		nla = tb[NETNSA_NSID];
 	} else {
 		NL_SET_ERR_MSG(extack, "Peer netns reference is missing");
 		return -EINVAL;