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Commit 3765d35e authored by David Ahern's avatar David Ahern Committed by David S. Miller
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net: ipv4: Convert inet_rtm_getroute to rcu versions of route lookup 



Convert inet_rtm_getroute to use ip_route_input_rcu and
ip_route_output_key_hash_rcu passing the fib_result arg to both.
The rcu lock is held through the creation of the response, so the
rtable/dst does not need to be attached to the skb and is passed
to rt_fill_info directly.

In converting from ip_route_output_key to ip_route_output_key_hash_rcu
the xfrm_lookup_route in ip_route_output_flow is dropped since
flowi4_proto is not set for a route get request.

Signed-off-by: default avatarDavid Ahern <dsahern@gmail.com>
Signed-off-by: default avatarRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d3166e0c

net/ipv4/route.c

+13 −8
Original line number Diff line number Diff line
@@ -2534,11 +2534,11 @@ struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 
}

EXPORT_SYMBOL_GPL(ip_route_output_flow);



/* called with rcu_read_lock held */

static int rt_fill_info(struct net *net,  __be32 dst, __be32 src, u32 table_id,

			struct flowi4 *fl4, struct sk_buff *skb, u32 portid,

			u32 seq)

			u32 seq, struct rtable *rt)

{

	struct rtable *rt = skb_rtable(skb);

	struct rtmsg *r;

	struct nlmsghdr *nlh;

	unsigned long expires = 0;
@@ -2653,6 +2653,7 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 
	struct net *net = sock_net(in_skb->sk);

	struct rtmsg *rtm;

	struct nlattr *tb[RTA_MAX+1];

	struct fib_result res = {};

	struct rtable *rt = NULL;

	struct flowi4 fl4;

	__be32 dst = 0;
@@ -2709,10 +2710,12 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 
	fl4.flowi4_mark = mark;

	fl4.flowi4_uid = uid;



	rcu_read_lock();



	if (iif) {

		struct net_device *dev;



		dev = __dev_get_by_index(net, iif);

		dev = dev_get_by_index_rcu(net, iif);

		if (!dev) {

			err = -ENODEV;

			goto errout_free;
@@ -2721,14 +2724,14 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 
		skb->protocol	= htons(ETH_P_IP);

		skb->dev	= dev;

		skb->mark	= mark;

		err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);

		err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos,

					 dev, &res);



		rt = skb_rtable(skb);

		if (err == 0 && rt->dst.error)

			err = -rt->dst.error;

	} else {

		rt = ip_route_output_key(net, &fl4);



		rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);

		err = 0;

		if (IS_ERR(rt))

			err = PTR_ERR(rt);
@@ -2737,7 +2740,6 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 
	if (err)

		goto errout_free;



	skb_dst_set(skb, &rt->dst);

	if (rtm->rtm_flags & RTM_F_NOTIFY)

		rt->rt_flags |= RTCF_NOTIFY;
@@ -2745,15 +2747,18 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 
		table_id = rt->rt_table_id;



	err = rt_fill_info(net, dst, src, table_id, &fl4, skb,

			   NETLINK_CB(in_skb).portid, nlh->nlmsg_seq);

			   NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, rt);

	if (err < 0)

		goto errout_free;



	rcu_read_unlock();



	err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);

errout:

	return err;



errout_free:

	rcu_read_unlock();

	kfree_skb(skb);

	goto errout;

}