From 1d3fd8a10bedb09006cfc963bfcf051c3021f626 Mon Sep 17 00:00:00 2001 From: Stephen Suryaputra Date: Sat, 27 Apr 2019 09:14:33 -0400 Subject: [PATCH] vrf: Use orig netdev to count Ip6InNoRoutes and a fresh route lookup when sending dest unreach 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 Reviewed-by: David Ahern Tested-by: David Ahern Reviewed-by: David Ahern Signed-off-by: David S. Miller --- net/ipv6/route.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 7178e32eb15d..b4899f0de0d0 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -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;