netlink: IFA_ADDRESS needs to go first

Golang uses the netlink interface RTM_GETADDR to query the network interfaces and IPs.
It assumes that the 1st attribute in the RTM_NEWADDR response is IFA_ADDRESS. This
patch changes the order in which RTM_NEWADDR attributes are sent to make
sure the IFA_ADDRESS goes first and IFA_LABEL last.

This does not seem to be documented anywhere but Linux sends RTM_NEWADDR responses
with the IFA_ADDRESS attribute first so we follow suit.

Signed-off-by: Waldemar Kozaczuk <[email protected]>

bsd/sys/compat/linux/linux_netlink.cc

@@ -599,10 +599,6 @@ netlink_process_getaddr_msg(struct socket *so, struct nlmsghdr *nlm)
 			ifm->ifa_prefixlen = get_sockaddr_mask_prefix_len(ifa->ifa_netmask);
 			ifm->ifa_flags = ifp->if_flags | ifp->if_drv_flags;
 			ifm->ifa_scope = 0; // FIXME:
-			if (nla_put_string(m, IFA_LABEL, ifp->if_xname)) {
-				error = ENOBUFS;
-				goto done;
-			}
 #ifdef INET6
 			if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET6){
 				// FreeBSD embeds the IPv6 scope ID in the IPv6 address
@@ -635,6 +631,10 @@ netlink_process_getaddr_msg(struct socket *so, struct nlmsghdr *nlm)
 					goto done;
 				}
 			}
+			if (nla_put_string(m, IFA_LABEL, ifp->if_xname)) {
+				error = ENOBUFS;
+				goto done;
+			}
 			nlmsg_end(m, nlh);
 		}