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vrf: Use orig netdev to count Ip6InNoRoutes and a fresh route lookup when sending dest unreach

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When there is no route to an IPv6 dest addr, skb_dst(skb) points
to loopback dev in the case of that the IP6CB(skb)->iif is
enslaved to a vrf. This causes Ip6InNoRoutes to be incremented on the
loopback dev. This also causes the lookup to fail on icmpv6_send() and
the dest unreachable to not sent and Ip6OutNoRoutes gets incremented on
the loopback dev.

To reproduce:
* Gateway configuration:
        ip link add dev vrf_258 type vrf table 258
        ip link set dev enp0s9 master vrf_258
        ip addr add 66:1/64 dev enp0s9
        ip -6 route add unreachable default metric 8192 table 258
        sysctl -w net.ipv6.conf.all.forwarding=1
        sysctl -w net.ipv6.conf.enp0s9.forwarding=1
* Sender configuration:
        ip addr add 66::2/64 dev enp0s9
        ip -6 route add default via 66::1
and ping 67::1 for example from the sender.

Fix this by counting on the original netdev and reset the skb dst to
force a fresh lookup.

v2: Fix typo of destination address in the repro steps.
v3: Simplify the loopback check (per David Ahern) and use reverse
    Christmas tree format (per David Miller).

Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Tested-by: David Ahern <dsahern@gmail.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Stephen Suryaputra 2019-04-27 09:14:33 -04:00 committed by David S. Miller
parent ca2fe2956a
commit 1d3fd8a10b
1 changed files with 17 additions and 6 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

23
net/ipv6/route.c
View file

@ -3668,23 +3668,34 @@ int ipv6_route_ioctl(struct net *net, unsigned int cmd, void __user *arg)
static int ip6_pkt_drop(struct sk_buff *skb, u8 code, int ipstats_mib_noroutes)
{
int type;
struct dst_entry *dst = skb_dst(skb);
struct net *net = dev_net(dst->dev);
struct inet6_dev *idev;
int type;
if (netif_is_l3_master(skb->dev) &&
dst->dev == net->loopback_dev)
idev = __in6_dev_get_safely(dev_get_by_index_rcu(net, IP6CB(skb)->iif));
else
idev = ip6_dst_idev(dst);
switch (ipstats_mib_noroutes) {
case IPSTATS_MIB_INNOROUTES:
type = ipv6_addr_type(&ipv6_hdr(skb)->daddr);
if (type == IPV6_ADDR_ANY) {
IP6_INC_STATS(dev_net(dst->dev),
__in6_dev_get_safely(skb->dev),
IPSTATS_MIB_INADDRERRORS);
IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
break;
}
/* FALLTHROUGH */
case IPSTATS_MIB_OUTNOROUTES:
IP6_INC_STATS(dev_net(dst->dev), ip6_dst_idev(dst),
ipstats_mib_noroutes);
IP6_INC_STATS(net, idev, ipstats_mib_noroutes);
break;
}
/* Start over by dropping the dst for l3mdev case */
if (netif_is_l3_master(skb->dev))
skb_dst_drop(skb);
icmpv6_send(skb, ICMPV6_DEST_UNREACH, code, 0);
kfree_skb(skb);
return 0;