ipv6: set rt6i_protocol properly in the route when it is installed

lxin · davem330 · commit b91d532928df · 2017-08-03T15:10:18.000-07:00
After commit c2ed188 ("net: ipv6: check route protocol when deleting routes"), ipv6 route checks rt protocol when trying to remove a rt entry. It introduced a side effect causing 'ip -6 route flush cache' not to work well. When flushing caches with iproute, all route caches get dumped from kernel then removed one by one by sending DELROUTE requests to kernel for each cache. The thing is iproute sends the request with the cache whose proto is set with RTPROT_REDIRECT by rt6_fill_node() when kernel dumps it. But in kernel the rt_cache protocol is still 0, which causes the cache not to be matched and removed. So the real reason is rt6i_protocol in the route is not set when it is allocated. As David Ahern's suggestion, this patch is to set rt6i_protocol properly in the route when it is installed and remove the codes setting rtm_protocol according to rt6i_flags in rt6_fill_node. This is also an improvement to keep rt6i_protocol consistent with rtm_protocol. Fixes: c2ed188 ("net: ipv6: check route protocol when deleting routes") Reported-by: Jianlin Shi <jishi@redhat.com> Suggested-by: David Ahern <dsahern@gmail.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
@@ -2351,6 +2351,7 @@ static void rt6_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_bu
 	if (on_link)
 		nrt->rt6i_flags &= ~RTF_GATEWAY;
 
+	nrt->rt6i_protocol = RTPROT_REDIRECT;
 	nrt->rt6i_gateway = *(struct in6_addr *)neigh->primary_key;
 
 	if (ip6_ins_rt(nrt))
@@ -2461,6 +2462,7 @@ static struct rt6_info *rt6_add_route_info(struct net *net,
 		.fc_dst_len	= prefixlen,
 		.fc_flags	= RTF_GATEWAY | RTF_ADDRCONF | RTF_ROUTEINFO |
 				  RTF_UP | RTF_PREF(pref),
+		.fc_protocol = RTPROT_RA,
 		.fc_nlinfo.portid = 0,
 		.fc_nlinfo.nlh = NULL,
 		.fc_nlinfo.nl_net = net,
@@ -2513,6 +2515,7 @@ struct rt6_info *rt6_add_dflt_router(const struct in6_addr *gwaddr,
 		.fc_ifindex	= dev->ifindex,
 		.fc_flags	= RTF_GATEWAY | RTF_ADDRCONF | RTF_DEFAULT |
 				  RTF_UP | RTF_EXPIRES | RTF_PREF(pref),
+		.fc_protocol = RTPROT_RA,
 		.fc_nlinfo.portid = 0,
 		.fc_nlinfo.nlh = NULL,
 		.fc_nlinfo.nl_net = dev_net(dev),
@@ -3424,14 +3427,6 @@ static int rt6_fill_node(struct net *net,
 	rtm->rtm_flags = 0;
 	rtm->rtm_scope = RT_SCOPE_UNIVERSE;
 	rtm->rtm_protocol = rt->rt6i_protocol;
-	if (rt->rt6i_flags & RTF_DYNAMIC)
-		rtm->rtm_protocol = RTPROT_REDIRECT;
-	else if (rt->rt6i_flags & RTF_ADDRCONF) {
-		if (rt->rt6i_flags & (RTF_DEFAULT | RTF_ROUTEINFO))
-			rtm->rtm_protocol = RTPROT_RA;
-		else
-			rtm->rtm_protocol = RTPROT_KERNEL;
-	}
 
 	if (rt->rt6i_flags & RTF_CACHE)
 		rtm->rtm_flags |= RTM_F_CLONED;
