[RFC PATCH net-next 06/10] ipv6: Avoid deleting RTF_CACHE route from ip6_route_del()

[Martin KaFai Lau <kafai@fb.com>]

Before patch 'Allow pmtu update on /128 via gateway route',
RTF_CACHE route was not created for DST_HOST.  It also requires changes on both
delete code path and rt6_select() code patch.

This patch fixes the delete code path to avoid deleting the RTF_CACHE
route by 'ip -6 r del...'

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Reviewed-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
---
 net/ipv6/route.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 75f3b5d..5d0fd6c 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1780,6 +1780,9 @@ static int ip6_route_del(struct fib6_config *cfg)
 
 	if (fn) {
 		for (rt = fn->leaf; rt; rt = rt->dst.rt6_next) {
+			if ((rt->rt6i_flags & RTF_CACHE) &&
+			    !(cfg->fc_flags & RTF_CACHE))
+				continue;
 			if (cfg->fc_ifindex &&
 			    (!rt->dst.dev ||
 			     rt->dst.dev->ifindex != cfg->fc_ifindex))
@@ -2424,6 +2427,9 @@ static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (rtm->rtm_type == RTN_LOCAL)
 		cfg->fc_flags |= RTF_LOCAL;
 
+	if (rtm->rtm_flags & RTM_F_CLONED)
+		cfg->fc_flags |= RTF_CACHE;
+
 	cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
 	cfg->fc_nlinfo.nlh = nlh;
 	cfg->fc_nlinfo.nl_net = sock_net(skb->sk);
-- 
1.8.1