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net: ipv4: Convert inet_rtm_getroute to rcu versions of route lookup

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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: David Ahern <dsahern@gmail.com>
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern 2017-05-25 10:42:36 -07:00 committed by David S. Miller
parent d3166e0c95
commit 3765d35ed8
1 changed files with 13 additions and 8 deletions
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21
net/ipv4/route.c
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@ -2534,11 +2534,11 @@ struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
} }
EXPORT_SYMBOL_GPL(ip_route_output_flow); 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, static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id,
struct flowi4 *fl4, struct sk_buff *skb, u32 portid, 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 rtmsg *r;
struct nlmsghdr *nlh; struct nlmsghdr *nlh;
unsigned long expires = 0; 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 net *net = sock_net(in_skb->sk);
struct rtmsg *rtm; struct rtmsg *rtm;
struct nlattr *tb[RTA_MAX+1]; struct nlattr *tb[RTA_MAX+1];
struct fib_result res = {};
struct rtable *rt = NULL; struct rtable *rt = NULL;
struct flowi4 fl4; struct flowi4 fl4;
__be32 dst = 0; __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_mark = mark;
fl4.flowi4_uid = uid; fl4.flowi4_uid = uid;
rcu_read_lock();
if (iif) { if (iif) {
struct net_device *dev; struct net_device *dev;
dev = __dev_get_by_index(net, iif); dev = dev_get_by_index_rcu(net, iif);
if (!dev) { if (!dev) {
err = -ENODEV; err = -ENODEV;
goto errout_free; 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->protocol = htons(ETH_P_IP);
skb->dev = dev; skb->dev = dev;
skb->mark = mark; 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); rt = skb_rtable(skb);
if (err == 0 && rt->dst.error) if (err == 0 && rt->dst.error)
err = -rt->dst.error; err = -rt->dst.error;
} else { } else {
rt = ip_route_output_key(net, &fl4); rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
err = 0; err = 0;
if (IS_ERR(rt)) if (IS_ERR(rt))
err = PTR_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) if (err)
goto errout_free; goto errout_free;
skb_dst_set(skb, &rt->dst);
if (rtm->rtm_flags & RTM_F_NOTIFY) if (rtm->rtm_flags & RTM_F_NOTIFY)
rt->rt_flags |= RTCF_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; table_id = rt->rt_table_id;
err = rt_fill_info(net, dst, src, table_id, &fl4, skb, 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) if (err < 0)
goto errout_free; goto errout_free;
rcu_read_unlock();
err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
errout: errout:
return err; return err;
errout_free: errout_free:
rcu_read_unlock();
kfree_skb(skb); kfree_skb(skb);
goto errout; goto errout;
} }