+static inline size_t fib_nlmsg_size(struct fib_info *fi)
+{
+ size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
+ + nla_total_size(4) /* RTA_TABLE */
+ + nla_total_size(4) /* RTA_DST */
+ + nla_total_size(4) /* RTA_PRIORITY */
+ + nla_total_size(4); /* RTA_PREFSRC */
+
+ /* space for nested metrics */
+ payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
+
+ if (fi->fib_nhs) {
+ /* Also handles the special case fib_nhs == 1 */
+
+ /* each nexthop is packed in an attribute */
+ size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
+
+ /* may contain flow and gateway attribute */
+ nhsize += 2 * nla_total_size(4);
+
+ /* all nexthops are packed in a nested attribute */
+ payload += nla_total_size(fi->fib_nhs * nhsize);
+ }
+
+ return payload;
+}
+