net: Set rtm_table to RT_TABLE_COMPAT for ipv6 for tables > 255

[ Upstream commit 97f0082a0592212fc15d4680f5a4d80f79a1687c ]

Set rtm_table to RT_TABLE_COMPAT for ipv6 for tables > 255 to
keep legacy software happy. This is similar to what was done for
ipv4 in commit 709772e6e065 ("net: Fix routing tables with
id > 255 for legacy software").

Signed-off-by: Kalash Nainwal <kalash@arista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index b0a7267..27c93ba 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3211,7 +3211,7 @@
 		table = rt->rt6i_table->tb6_id;
 	else
 		table = RT6_TABLE_UNSPEC;
-	rtm->rtm_table = table;
+	rtm->rtm_table = table < 256 ? table : RT_TABLE_COMPAT;
 	if (nla_put_u32(skb, RTA_TABLE, table))
 		goto nla_put_failure;
 	if (rt->rt6i_flags & RTF_REJECT) {