[mirror_ubuntu-artful-kernel.git] / Documentation / networking / ipvlan.txt


                            IPVLAN Driver HOWTO

Initial Release:
	Mahesh Bandewar <maheshb AT google.com>

1. Introduction:
	This is conceptually very similar to the macvlan driver with one major
exception of using L3 for mux-ing /demux-ing among slaves. This property makes
the master device share the L2 with it's slave devices. I have developed this
driver in conjunction with network namespaces and not sure if there is use case
outside of it.


2. Building and Installation:
	In order to build the driver, please select the config item CONFIG_IPVLAN.
The driver can be built into the kernel (CONFIG_IPVLAN=y) or as a module
(CONFIG_IPVLAN=m).


3. Configuration:
	There are no module parameters for this driver and it can be configured
using IProute2/ip utility.

	ip link add link <master-dev> name <slave-dev> type ipvlan mode { l2 | l3 | l3s }

	e.g. ip link add link eth0 name ipvl0 type ipvlan mode l2


4. Operating modes:
	IPvlan has two modes of operation - L2 and L3. For a given master device,
you can select one of these two modes and all slaves on that master will
operate in the same (selected) mode. The RX mode is almost identical except
that in L3 mode the slaves wont receive any multicast / broadcast traffic.
L3 mode is more restrictive since routing is controlled from the other (mostly)
default namespace.

4.1 L2 mode:
	In this mode TX processing happens on the stack instance attached to the
slave device and packets are switched and queued to the master device to send
out. In this mode the slaves will RX/TX multicast and broadcast (if applicable)
as well.

4.2 L3 mode:
	In this mode TX processing up to L3 happens on the stack instance attached
to the slave device and packets are switched to the stack instance of the
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
case could very well define which device to choose. if one of the following
situations defines your use case then you can choose to use ipvlan -
	(a) The Linux host that is connected to the external switch / router has
policy configured that allows only one mac per port.
	(b) No of virtual devices created on a master exceed the mac capacity and
puts the NIC in promiscuous mode and degraded performance is a concern.
	(c) If the slave device is to be put into the hostile / untrusted network
namespace where L2 on the slave could be changed / misused.


6. Example configuration:

  +=============================================================+
  |  Host: host1                                                |
  |                                                             |
  |   +----------------------+      +----------------------+    |
  |   |   NS:ns0             |      |  NS:ns1              |    |
  |   |                      |      |                      |    |
  |   |                      |      |                      |    |
  |   |        ipvl0         |      |         ipvl1        |    |
  |   +----------#-----------+      +-----------#----------+    |
  |              #                              #               |
  |              ################################               |
  |                              # eth0                         |
  +==============================#==============================+


	(a) Create two network namespaces - ns0, ns1
		ip netns add ns0
		ip netns add ns1

	(b) Create two ipvlan slaves on eth0 (master device)
		ip link add link eth0 ipvl0 type ipvlan mode l2
		ip link add link eth0 ipvl1 type ipvlan mode l2

	(c) Assign slaves to the respective network namespaces
		ip link set dev ipvl0 netns ns0
		ip link set dev ipvl1 netns ns1

	(d) Now switch to the namespace (ns0 or ns1) to configure the slave devices
		- For ns0
			(1) ip netns exec ns0 bash
			(2) ip link set dev ipvl0 up
			(3) ip link set dev lo up
			(4) ip -4 addr add 127.0.0.1 dev lo
			(5) ip -4 addr add $IPADDR dev ipvl0
			(6) ip -4 route add default via $ROUTER dev ipvl0
		- For ns1
			(1) ip netns exec ns1 bash
			(2) ip link set dev ipvl1 up
			(3) ip link set dev lo up
			(4) ip -4 addr add 127.0.0.1 dev lo
			(5) ip -4 addr add $IPADDR dev ipvl1
			(6) ip -4 route add default via $ROUTER dev ipvl1
Commit	Line	Data
2ad7bf36 MB	1
	2	IPVLAN Driver HOWTO
	3
	4	Initial Release:
	5	Mahesh Bandewar <maheshb AT google.com>
	6
	7	1. Introduction:
	8	This is conceptually very similar to the macvlan driver with one major
	9	exception of using L3 for mux-ing /demux-ing among slaves. This property makes
	10	the master device share the L2 with it's slave devices. I have developed this
edb9a1b8	11	driver in conjunction with network namespaces and not sure if there is use case
2ad7bf36 MB	12	outside of it.
	13
	14
	15	2. Building and Installation:
	16	In order to build the driver, please select the config item CONFIG_IPVLAN.
	17	The driver can be built into the kernel (CONFIG_IPVLAN=y) or as a module
	18	(CONFIG_IPVLAN=m).
	19
	20
	21	3. Configuration:
	22	There are no module parameters for this driver and it can be configured
	23	using IProute2/ip utility.
	24
75674c4c	25	ip link add link <master-dev> name <slave-dev> type ipvlan mode { l2 \| l3 \| l3s }
2ad7bf36	26
75674c4c	27	e.g. ip link add link eth0 name ipvl0 type ipvlan mode l2
2ad7bf36 MB	28
	29
	30	4. Operating modes:
	31	IPvlan has two modes of operation - L2 and L3. For a given master device,
	32	you can select one of these two modes and all slaves on that master will
	33	operate in the same (selected) mode. The RX mode is almost identical except
	34	that in L3 mode the slaves wont receive any multicast / broadcast traffic.
	35	L3 mode is more restrictive since routing is controlled from the other (mostly)
	36	default namespace.
	37
	38	4.1 L2 mode:
	39	In this mode TX processing happens on the stack instance attached to the
	40	slave device and packets are switched and queued to the master device to send
	41	out. In this mode the slaves will RX/TX multicast and broadcast (if applicable)
	42	as well.
	43
	44	4.2 L3 mode:
edb9a1b8	45	In this mode TX processing up to L3 happens on the stack instance attached
2ad7bf36 MB	46	to the slave device and packets are switched to the stack instance of the
	47	master device for the L2 processing and routing from that instance will be
	48	used before packets are queued on the outbound device. In this mode the slaves
	49	will not receive nor can send multicast / broadcast traffic.
	50
4fbae7d8 MB	51	4.3 L3S mode:
	52	This is very similar to the L3 mode except that iptables (conn-tracking)
	53	works in this mode and hence it is L3-symmetric (L3s). This will have slightly less
	54	performance but that shouldn't matter since you are choosing this mode over plain-L3
	55	mode to make conn-tracking work.
2ad7bf36 MB	56
	57	5. What to choose (macvlan vs. ipvlan)?
	58	These two devices are very similar in many regards and the specific use
	59	case could very well define which device to choose. if one of the following
	60	situations defines your use case then you can choose to use ipvlan -
	61	(a) The Linux host that is connected to the external switch / router has
	62	policy configured that allows only one mac per port.
	63	(b) No of virtual devices created on a master exceed the mac capacity and
edb9a1b8	64	puts the NIC in promiscuous mode and degraded performance is a concern.
2ad7bf36 MB	65	(c) If the slave device is to be put into the hostile / untrusted network
	66	namespace where L2 on the slave could be changed / misused.
	67
	68
	69	6. Example configuration:
	70
	71	+=============================================================+
	72	\| Host: host1 \|
	73	\| \|
	74	\| +----------------------+ +----------------------+ \|
	75	\| \| NS:ns0 \| \| NS:ns1 \| \|
	76	\| \| \| \| \| \|
	77	\| \| \| \| \| \|
	78	\| \| ipvl0 \| \| ipvl1 \| \|
	79	\| +----------#-----------+ +-----------#----------+ \|
	80	\| # # \|
	81	\| ################################ \|
	82	\| # eth0 \|
	83	+==============================#==============================+
	84
	85
	86	(a) Create two network namespaces - ns0, ns1
	87	ip netns add ns0
	88	ip netns add ns1
	89
	90	(b) Create two ipvlan slaves on eth0 (master device)
	91	ip link add link eth0 ipvl0 type ipvlan mode l2
	92	ip link add link eth0 ipvl1 type ipvlan mode l2
	93
	94	(c) Assign slaves to the respective network namespaces
	95	ip link set dev ipvl0 netns ns0
	96	ip link set dev ipvl1 netns ns1
	97
	98	(d) Now switch to the namespace (ns0 or ns1) to configure the slave devices
	99	- For ns0
	100	(1) ip netns exec ns0 bash
	101	(2) ip link set dev ipvl0 up
	102	(3) ip link set dev lo up
	103	(4) ip -4 addr add 127.0.0.1 dev lo
	104	(5) ip -4 addr add $IPADDR dev ipvl0
	105	(6) ip -4 route add default via $ROUTER dev ipvl0
	106	- For ns1
	107	(1) ip netns exec ns1 bash
	108	(2) ip link set dev ipvl1 up
	109	(3) ip link set dev lo up
	110	(4) ip -4 addr add 127.0.0.1 dev lo
	111	(5) ip -4 addr add $IPADDR dev ipvl1
	112	(6) ip -4 route add default via $ROUTER dev ipvl1