ipvlan: Introduce l3s mode
In a typical IPvlan L3 setup where master is in default-ns and
each slave is into different (slave) ns. In this setup egress
packet processing for traffic originating from slave-ns will
hit all NF_HOOKs in slave-ns as well as default-ns. However same
is not true for ingress processing. All these NF_HOOKs are
hit only in the slave-ns skipping them in the default-ns.
IPvlan in L3 mode is restrictive and if admins want to deploy
iptables rules in default-ns, this asymmetric data path makes it
impossible to do so.
This patch makes use of the l3_rcv() (added as part of l3mdev
enhancements) to perform input route lookup on RX packets without
changing the skb->dev and then uses nf_hook at NF_INET_LOCAL_IN
to change the skb->dev just before handing over skb to L4.
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
CC: David Ahern <dsa@cumulusnetworks.com>
Reviewed-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/Documentation/networking/ipvlan.txt b/Documentation/networking/ipvlan.txt
index 14422f8..24196ce 100644
--- a/Documentation/networking/ipvlan.txt
+++ b/Documentation/networking/ipvlan.txt
@@ -22,7 +22,7 @@
There are no module parameters for this driver and it can be configured
using IProute2/ip utility.
- ip link add link <master-dev> <slave-dev> type ipvlan mode { l2 | L3 }
+ ip link add link <master-dev> <slave-dev> type ipvlan mode { l2 | l3 | l3s }
e.g. ip link add link ipvl0 eth0 type ipvlan mode l2
@@ -48,6 +48,11 @@
used before packets are queued on the outbound device. In this mode the slaves
will not receive nor can send multicast / broadcast traffic.
+4.3 L3S mode:
+ This is very similar to the L3 mode except that iptables (conn-tracking)
+works in this mode and hence it is L3-symmetric (L3s). This will have slightly less
+performance but that shouldn't matter since you are choosing this mode over plain-L3
+mode to make conn-tracking work.
5. What to choose (macvlan vs. ipvlan)?
These two devices are very similar in many regards and the specific use