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. Also, the flow struct
adjustments from __ip_route_output_key_hash are added to make sure
the route request logic is not altered by the conversion.
Signed-off-by: David Ahern <d...@cumulusnetworks.com>
---
net/ipv4/route.c | 27 +++++++++++++++++++--------
1 file changed, 19 insertions(+), 8 deletions(-)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 3142cd802e79..03ddc03c185a 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2467,11 +2467,11 @@ 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, int event)
+ u32 seq, int event, struct rtable *rt)
{
- struct rtable *rt = skb_rtable(skb);
struct rtmsg *r;
struct nlmsghdr *nlh;
unsigned long expires = 0;
@@ -2585,10 +2585,12 @@ 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;
__be32 src = 0;
+ __u8 tos;
u32 iif;
int err;
int mark;
@@ -2630,15 +2632,20 @@ static int inet_rtm_getroute(struct sk_buff *in_skb,
struct nlmsghdr *nlh)
memset(&fl4, 0, sizeof(fl4));
fl4.daddr = dst;
fl4.saddr = src;
- fl4.flowi4_tos = rtm->rtm_tos;
+ tos = rtm->rtm_tos & (IPTOS_RT_MASK | RTO_ONLINK);
+ fl4.flowi4_tos = tos & IPTOS_RT_MASK;
+ fl4.flowi4_scope = ((tos & RTO_ONLINK) ?
+ RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
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;
@@ -2647,14 +2654,16 @@ 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);
+ fl4.flowi4_iif = LOOPBACK_IFINDEX;
+ rt = ip_route_output_key_hash_rcu(net, &fl4, &res, -1);
err = 0;
if (IS_ERR(rt))
err = PTR_ERR(rt);
@@ -2663,7 +2672,6 @@ 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;
@@ -2672,15 +2680,18 @@ static int inet_rtm_getroute(struct sk_buff *in_skb,
struct nlmsghdr *nlh)
err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
- RTM_NEWROUTE);
+ RTM_NEWROUTE, 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;
}
--
2.1.4
