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authorMahesh Bandewar <maheshb@google.com>2016-09-16 22:59:19 +0300
committerDavid S. Miller <davem@davemloft.net>2016-09-19 08:25:22 +0300
commit4fbae7d83c98c30efcf0a2a2ac55fbb75ef5a1a5 (patch)
tree3ea819d38ad4fbbae8d4db166f58451c2a78ee20 /Documentation/networking
parente8bffe0cf964f0330595bb376b74921cccdaac88 (diff)
downloadlinux-4fbae7d83c98c30efcf0a2a2ac55fbb75ef5a1a5.tar.xz
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>
Diffstat (limited to 'Documentation/networking')
-rw-r--r--Documentation/networking/ipvlan.txt7
1 files changed, 6 insertions, 1 deletions
diff --git a/Documentation/networking/ipvlan.txt b/Documentation/networking/ipvlan.txt
index 14422f8fcdc4..24196cef7c91 100644
--- a/Documentation/networking/ipvlan.txt
+++ b/Documentation/networking/ipvlan.txt
@@ -22,7 +22,7 @@ The driver can be built into the kernel (CONFIG_IPVLAN=y) or as a module
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 @@ master device for the L2 processing and routing from that instance will be
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