On Tue, Oct 20, 2015 at 4:47 PM, Brenden Blanco <bbla...@plumgrid.com> wrote:
> In the ipv4 outbound path of an ipvlan device in l3 mode, the ifindex is
> being grabbed from dev_get_iflink. This works for the physical device
> case, since as the documentation of that function notes: "Physical
> interfaces have the same 'ifindex' and 'iflink' values.". However, if
> the master device is a veth, and the pairs are in separate net
> namespaces, the route lookup will fail with -ENODEV due to outer veth
> pair being in a separate namespace from the ipvlan master/routing
> namespace.
>
> ns0 | ns1 | ns2
> veth0a--|--veth0b--|--ipvl0
>
interesting use case.
> In ipvlan_process_v4_outbound(), a packet sent from ipvl0 in the above
> configuration will pass fl.flowi4_oif == veth0a to
> ip_route_output_flow(), but *net == ns1.
>
> Notice also that ipv6 processing is not using iflink. Since there is a
> discrepancy in usage, fixup both v4 and v6 case to use local dev
> variable.
>
> Tested this with l3 ipvlan on top of veth, as well as with single
> physical interface in the top namespace.
>
> Signed-off-by: Brenden Blanco <bbla...@plumgrid.com>
Acked-by: Mahesh Bandewar <mahe...@google.com>
> ---
> drivers/net/ipvlan/ipvlan_core.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ipvlan/ipvlan_core.c
> b/drivers/net/ipvlan/ipvlan_core.c
> index 24f8dbc..d50887e 100644
> --- a/drivers/net/ipvlan/ipvlan_core.c
> +++ b/drivers/net/ipvlan/ipvlan_core.c
> @@ -348,7 +348,7 @@ static int ipvlan_process_v4_outbound(struct sk_buff *skb)
> struct rtable *rt;
> int err, ret = NET_XMIT_DROP;
> struct flowi4 fl4 = {
> - .flowi4_oif = dev_get_iflink(dev),
> + .flowi4_oif = dev->ifindex,
> .flowi4_tos = RT_TOS(ip4h->tos),
> .flowi4_flags = FLOWI_FLAG_ANYSRC,
> .daddr = ip4h->daddr,
> @@ -386,7 +386,7 @@ static int ipvlan_process_v6_outbound(struct sk_buff *skb)
> struct dst_entry *dst;
> int err, ret = NET_XMIT_DROP;
> struct flowi6 fl6 = {
> - .flowi6_iif = skb->dev->ifindex,
> + .flowi6_iif = dev->ifindex,
> .daddr = ip6h->daddr,
> .saddr = ip6h->saddr,
> .flowi6_flags = FLOWI_FLAG_ANYSRC,
> --
> 2.6.1
>
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