Commit b91d5329 authored Aug 03, 2017 by Xin Long Committed by David S. Miller Aug 03, 2017

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



After commit c2ed1880 ("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: c2ed1880 ("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>

parent 2dda6400

net/ipv6/route.c

+3 −8

Original line number	Diff line number	Diff line
		@@ -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;

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