!913 [sync] PR-906: ipv6: Add lwtunnel encap size of all siblings in nexthop calculation

Merge Pull Request from: @openeuler-sync-bot 
 

Origin pull request: 
https://gitee.com/openeuler/kernel/pulls/906 
 
PR sync from: Lu Wei luwei32@huawei.com https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/thread/P2VNBKLIL5YGSGNPIHF44HRLVST76J4E/ 
 
Link:https://gitee.com/openeuler/kernel/pulls/913 

Reviewed-by: Yue Haibing <yuehaibing@huawei.com> 
Reviewed-by: Jialin Zhang <zhangjialin11@huawei.com> 
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com> 

net/ipv6/route.c

@@ -5439,16 +5439,17 @@ static size_t rt6_nlmsg_size(struct fib6_info *f6i)
 		nexthop_for_each_fib6_nh(f6i->nh, rt6_nh_nlmsg_size,
 					 &nexthop_len);
 	} else {
+		struct fib6_info *sibling, *next_sibling;
 		struct fib6_nh *nh = f6i->fib6_nh;
 
 		nexthop_len = 0;
 		if (f6i->fib6_nsiblings) {
-			nexthop_len = nla_total_size(0)	 /* RTA_MULTIPATH */
-				    + NLA_ALIGN(sizeof(struct rtnexthop))
-				    + nla_total_size(16) /* RTA_GATEWAY */
-				    + lwtunnel_get_encap_size(nh->fib_nh_lws);
+			rt6_nh_nlmsg_size(nh, &nexthop_len);
 
-			nexthop_len *= f6i->fib6_nsiblings;
+			list_for_each_entry_safe(sibling, next_sibling,
+						 &f6i->fib6_siblings, fib6_siblings) {
+				rt6_nh_nlmsg_size(sibling->fib6_nh, &nexthop_len);
+			}
 		}
 		nexthop_len += lwtunnel_get_encap_size(nh->fib_nh_lws);
 	}