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Based on kernel version 4.13.3. Page generated on 2017-09-23 13:55 EST.

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
11	driver in conjunction with network namespaces and not sure if there is use case
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	
25		ip link add link <master-dev> name <slave-dev> type ipvlan mode { l2 | l3 | l3s }
26	
27		e.g. ip link add link eth0 name ipvl0 type ipvlan mode l2
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:
45		In this mode TX processing up to L3 happens on the stack instance attached
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	
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.
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
64	puts the NIC in promiscuous mode and degraded performance is a concern.
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
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