net: vrf: Documentation update
Update vrf documentation for changes made to 4.4 - 4.8 kernels and iproute2 support for vrf keyword. Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Родитель
b38a75d2d3
Коммит
6e07653765
|
@ -15,9 +15,9 @@ the use of higher priority ip rules (Policy Based Routing, PBR) to take
|
|||
precedence over the VRF device rules directing specific traffic as desired.
|
||||
|
||||
In addition, VRF devices allow VRFs to be nested within namespaces. For
|
||||
example network namespaces provide separation of network interfaces at L1
|
||||
(Layer 1 separation), VLANs on the interfaces within a namespace provide
|
||||
L2 separation and then VRF devices provide L3 separation.
|
||||
example network namespaces provide separation of network interfaces at the
|
||||
device layer, VLANs on the interfaces within a namespace provide L2 separation
|
||||
and then VRF devices provide L3 separation.
|
||||
|
||||
Design
|
||||
------
|
||||
|
@ -37,21 +37,22 @@ are then enslaved to a VRF device:
|
|||
+------+ +------+
|
||||
|
||||
Packets received on an enslaved device and are switched to the VRF device
|
||||
using an rx_handler which gives the impression that packets flow through
|
||||
the VRF device. Similarly on egress routing rules are used to send packets
|
||||
to the VRF device driver before getting sent out the actual interface. This
|
||||
allows tcpdump on a VRF device to capture all packets into and out of the
|
||||
VRF as a whole.[1] Similarly, netfilter [2] and tc rules can be applied
|
||||
using the VRF device to specify rules that apply to the VRF domain as a whole.
|
||||
in the IPv4 and IPv6 processing stacks giving the impression that packets
|
||||
flow through the VRF device. Similarly on egress routing rules are used to
|
||||
send packets to the VRF device driver before getting sent out the actual
|
||||
interface. This allows tcpdump on a VRF device to capture all packets into
|
||||
and out of the VRF as a whole.[1] Similarly, netfilter[2] and tc rules can be
|
||||
applied using the VRF device to specify rules that apply to the VRF domain
|
||||
as a whole.
|
||||
|
||||
[1] Packets in the forwarded state do not flow through the device, so those
|
||||
packets are not seen by tcpdump. Will revisit this limitation in a
|
||||
future release.
|
||||
|
||||
[2] Iptables on ingress is limited to NF_INET_PRE_ROUTING only with skb->dev
|
||||
set to real ingress device and egress is limited to NF_INET_POST_ROUTING.
|
||||
Will revisit this limitation in a future release.
|
||||
|
||||
[2] Iptables on ingress supports PREROUTING with skb->dev set to the real
|
||||
ingress device and both INPUT and PREROUTING rules with skb->dev set to
|
||||
the VRF device. For egress POSTROUTING and OUTPUT rules can be written
|
||||
using either the VRF device or real egress device.
|
||||
|
||||
Setup
|
||||
-----
|
||||
|
@ -59,23 +60,33 @@ Setup
|
|||
e.g, ip link add vrf-blue type vrf table 10
|
||||
ip link set dev vrf-blue up
|
||||
|
||||
2. Rules are added that send lookups to the associated FIB table when the
|
||||
iif or oif is the VRF device. e.g.,
|
||||
2. An l3mdev FIB rule directs lookups to the table associated with the device.
|
||||
A single l3mdev rule is sufficient for all VRFs. The VRF device adds the
|
||||
l3mdev rule for IPv4 and IPv6 when the first device is created with a
|
||||
default preference of 1000. Users may delete the rule if desired and add
|
||||
with a different priority or install per-VRF rules.
|
||||
|
||||
Prior to the v4.8 kernel iif and oif rules are needed for each VRF device:
|
||||
ip ru add oif vrf-blue table 10
|
||||
ip ru add iif vrf-blue table 10
|
||||
|
||||
Set the default route for the table (and hence default route for the VRF).
|
||||
e.g, ip route add table 10 prohibit default
|
||||
3. Set the default route for the table (and hence default route for the VRF).
|
||||
ip route add table 10 unreachable default
|
||||
|
||||
3. Enslave L3 interfaces to a VRF device.
|
||||
e.g, ip link set dev eth1 master vrf-blue
|
||||
4. Enslave L3 interfaces to a VRF device.
|
||||
ip link set dev eth1 master vrf-blue
|
||||
|
||||
Local and connected routes for enslaved devices are automatically moved to
|
||||
the table associated with VRF device. Any additional routes depending on
|
||||
the enslaved device will need to be reinserted following the enslavement.
|
||||
the enslaved device are dropped and will need to be reinserted to the VRF
|
||||
FIB table following the enslavement.
|
||||
|
||||
4. Additional VRF routes are added to associated table.
|
||||
e.g., ip route add table 10 ...
|
||||
The IPv6 sysctl option keep_addr_on_down can be enabled to keep IPv6 global
|
||||
addresses as VRF enslavement changes.
|
||||
sysctl -w net.ipv6.conf.all.keep_addr_on_down=1
|
||||
|
||||
5. Additional VRF routes are added to associated table.
|
||||
ip route add table 10 ...
|
||||
|
||||
|
||||
Applications
|
||||
|
@ -87,39 +98,34 @@ VRF device:
|
|||
|
||||
or to specify the output device using cmsg and IP_PKTINFO.
|
||||
|
||||
TCP services running in the default VRF context (ie., not bound to any VRF
|
||||
device) can work across all VRF domains by enabling the tcp_l3mdev_accept
|
||||
sysctl option:
|
||||
sysctl -w net.ipv4.tcp_l3mdev_accept=1
|
||||
|
||||
Limitations
|
||||
-----------
|
||||
Index of original ingress interface is not available via cmsg. Will address
|
||||
soon.
|
||||
netfilter rules on the VRF device can be used to limit access to services
|
||||
running in the default VRF context as well.
|
||||
|
||||
The default VRF does not have limited scope with respect to port bindings.
|
||||
That is, if a process does a wildcard bind to a port in the default VRF it
|
||||
owns the port across all VRF domains within the network namespace.
|
||||
|
||||
################################################################################
|
||||
|
||||
Using iproute2 for VRFs
|
||||
=======================
|
||||
VRF devices do *not* have to start with 'vrf-'. That is a convention used here
|
||||
for emphasis of the device type, similar to use of 'br' in bridge names.
|
||||
iproute2 supports the vrf keyword as of v4.7. For backwards compatibility this
|
||||
section lists both commands where appropriate -- with the vrf keyword and the
|
||||
older form without it.
|
||||
|
||||
1. Create a VRF
|
||||
|
||||
To instantiate a VRF device and associate it with a table:
|
||||
$ ip link add dev NAME type vrf table ID
|
||||
|
||||
Remember to add the ip rules as well:
|
||||
$ ip ru add oif NAME table 10
|
||||
$ ip ru add iif NAME table 10
|
||||
$ ip -6 ru add oif NAME table 10
|
||||
$ ip -6 ru add iif NAME table 10
|
||||
|
||||
Without the rules route lookups are not directed to the table.
|
||||
|
||||
For example:
|
||||
$ ip link add dev vrf-blue type vrf table 10
|
||||
$ ip ru add pref 200 oif vrf-blue table 10
|
||||
$ ip ru add pref 200 iif vrf-blue table 10
|
||||
$ ip -6 ru add pref 200 oif vrf-blue table 10
|
||||
$ ip -6 ru add pref 200 iif vrf-blue table 10
|
||||
|
||||
As of v4.8 the kernel supports the l3mdev FIB rule where a single rule
|
||||
covers all VRFs. The l3mdev rule is created for IPv4 and IPv6 on first
|
||||
device create.
|
||||
|
||||
2. List VRFs
|
||||
|
||||
|
@ -129,16 +135,16 @@ for emphasis of the device type, similar to use of 'br' in bridge names.
|
|||
|
||||
For example:
|
||||
$ ip -d link show type vrf
|
||||
11: vrf-mgmt: <NOARP,MASTER,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
|
||||
11: mgmt: <NOARP,MASTER,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
|
||||
link/ether 72:b3:ba:91:e2:24 brd ff:ff:ff:ff:ff:ff promiscuity 0
|
||||
vrf table 1 addrgenmode eui64
|
||||
12: vrf-red: <NOARP,MASTER,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
|
||||
12: red: <NOARP,MASTER,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
|
||||
link/ether b6:6f:6e:f6:da:73 brd ff:ff:ff:ff:ff:ff promiscuity 0
|
||||
vrf table 10 addrgenmode eui64
|
||||
13: vrf-blue: <NOARP,MASTER,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
|
||||
13: blue: <NOARP,MASTER,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
|
||||
link/ether 36:62:e8:7d:bb:8c brd ff:ff:ff:ff:ff:ff promiscuity 0
|
||||
vrf table 66 addrgenmode eui64
|
||||
14: vrf-green: <NOARP,MASTER,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
|
||||
14: green: <NOARP,MASTER,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
|
||||
link/ether e6:28:b8:63:70:bb brd ff:ff:ff:ff:ff:ff promiscuity 0
|
||||
vrf table 81 addrgenmode eui64
|
||||
|
||||
|
@ -146,43 +152,44 @@ for emphasis of the device type, similar to use of 'br' in bridge names.
|
|||
Or in brief output:
|
||||
|
||||
$ ip -br link show type vrf
|
||||
vrf-mgmt UP 72:b3:ba:91:e2:24 <NOARP,MASTER,UP,LOWER_UP>
|
||||
vrf-red UP b6:6f:6e:f6:da:73 <NOARP,MASTER,UP,LOWER_UP>
|
||||
vrf-blue UP 36:62:e8:7d:bb:8c <NOARP,MASTER,UP,LOWER_UP>
|
||||
vrf-green UP e6:28:b8:63:70:bb <NOARP,MASTER,UP,LOWER_UP>
|
||||
mgmt UP 72:b3:ba:91:e2:24 <NOARP,MASTER,UP,LOWER_UP>
|
||||
red UP b6:6f:6e:f6:da:73 <NOARP,MASTER,UP,LOWER_UP>
|
||||
blue UP 36:62:e8:7d:bb:8c <NOARP,MASTER,UP,LOWER_UP>
|
||||
green UP e6:28:b8:63:70:bb <NOARP,MASTER,UP,LOWER_UP>
|
||||
|
||||
|
||||
3. Assign a Network Interface to a VRF
|
||||
|
||||
Network interfaces are assigned to a VRF by enslaving the netdevice to a
|
||||
VRF device:
|
||||
$ ip link set dev NAME master VRF-NAME
|
||||
$ ip link set dev NAME master NAME
|
||||
|
||||
On enslavement connected and local routes are automatically moved to the
|
||||
table associated with the VRF device.
|
||||
|
||||
For example:
|
||||
$ ip link set dev eth0 master vrf-mgmt
|
||||
$ ip link set dev eth0 master mgmt
|
||||
|
||||
|
||||
4. Show Devices Assigned to a VRF
|
||||
|
||||
To show devices that have been assigned to a specific VRF add the master
|
||||
option to the ip command:
|
||||
$ ip link show master VRF-NAME
|
||||
$ ip link show vrf NAME
|
||||
$ ip link show master NAME
|
||||
|
||||
For example:
|
||||
$ ip link show master vrf-red
|
||||
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vrf-red state UP mode DEFAULT group default qlen 1000
|
||||
$ ip link show vrf red
|
||||
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master red state UP mode DEFAULT group default qlen 1000
|
||||
link/ether 02:00:00:00:02:02 brd ff:ff:ff:ff:ff:ff
|
||||
4: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vrf-red state UP mode DEFAULT group default qlen 1000
|
||||
4: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master red state UP mode DEFAULT group default qlen 1000
|
||||
link/ether 02:00:00:00:02:03 brd ff:ff:ff:ff:ff:ff
|
||||
7: eth5: <BROADCAST,MULTICAST> mtu 1500 qdisc noop master vrf-red state DOWN mode DEFAULT group default qlen 1000
|
||||
7: eth5: <BROADCAST,MULTICAST> mtu 1500 qdisc noop master red state DOWN mode DEFAULT group default qlen 1000
|
||||
link/ether 02:00:00:00:02:06 brd ff:ff:ff:ff:ff:ff
|
||||
|
||||
|
||||
Or using the brief output:
|
||||
$ ip -br link show master vrf-red
|
||||
$ ip -br link show master red
|
||||
eth1 UP 02:00:00:00:02:02 <BROADCAST,MULTICAST,UP,LOWER_UP>
|
||||
eth2 UP 02:00:00:00:02:03 <BROADCAST,MULTICAST,UP,LOWER_UP>
|
||||
eth5 DOWN 02:00:00:00:02:06 <BROADCAST,MULTICAST>
|
||||
|
@ -192,14 +199,15 @@ for emphasis of the device type, similar to use of 'br' in bridge names.
|
|||
|
||||
To list neighbor entries associated with devices enslaved to a VRF device
|
||||
add the master option to the ip command:
|
||||
$ ip [-6] neigh show master VRF-NAME
|
||||
$ ip [-6] neigh show vrf NAME
|
||||
$ ip [-6] neigh show master NAME
|
||||
|
||||
For example:
|
||||
$ ip neigh show master vrf-red
|
||||
$ ip neigh show vrf red
|
||||
10.2.1.254 dev eth1 lladdr a6:d9:c7:4f:06:23 REACHABLE
|
||||
10.2.2.254 dev eth2 lladdr 5e:54:01:6a:ee:80 REACHABLE
|
||||
|
||||
$ ip -6 neigh show master vrf-red
|
||||
$ ip -6 neigh show vrf red
|
||||
2002:1::64 dev eth1 lladdr a6:d9:c7:4f:06:23 REACHABLE
|
||||
|
||||
|
||||
|
@ -207,11 +215,12 @@ for emphasis of the device type, similar to use of 'br' in bridge names.
|
|||
|
||||
To show addresses for interfaces associated with a VRF add the master
|
||||
option to the ip command:
|
||||
$ ip addr show master VRF-NAME
|
||||
$ ip addr show vrf NAME
|
||||
$ ip addr show master NAME
|
||||
|
||||
For example:
|
||||
$ ip addr show master vrf-red
|
||||
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vrf-red state UP group default qlen 1000
|
||||
$ ip addr show vrf red
|
||||
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master red state UP group default qlen 1000
|
||||
link/ether 02:00:00:00:02:02 brd ff:ff:ff:ff:ff:ff
|
||||
inet 10.2.1.2/24 brd 10.2.1.255 scope global eth1
|
||||
valid_lft forever preferred_lft forever
|
||||
|
@ -219,7 +228,7 @@ for emphasis of the device type, similar to use of 'br' in bridge names.
|
|||
valid_lft forever preferred_lft forever
|
||||
inet6 fe80::ff:fe00:202/64 scope link
|
||||
valid_lft forever preferred_lft forever
|
||||
4: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vrf-red state UP group default qlen 1000
|
||||
4: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master red state UP group default qlen 1000
|
||||
link/ether 02:00:00:00:02:03 brd ff:ff:ff:ff:ff:ff
|
||||
inet 10.2.2.2/24 brd 10.2.2.255 scope global eth2
|
||||
valid_lft forever preferred_lft forever
|
||||
|
@ -227,11 +236,11 @@ for emphasis of the device type, similar to use of 'br' in bridge names.
|
|||
valid_lft forever preferred_lft forever
|
||||
inet6 fe80::ff:fe00:203/64 scope link
|
||||
valid_lft forever preferred_lft forever
|
||||
7: eth5: <BROADCAST,MULTICAST> mtu 1500 qdisc noop master vrf-red state DOWN group default qlen 1000
|
||||
7: eth5: <BROADCAST,MULTICAST> mtu 1500 qdisc noop master red state DOWN group default qlen 1000
|
||||
link/ether 02:00:00:00:02:06 brd ff:ff:ff:ff:ff:ff
|
||||
|
||||
Or in brief format:
|
||||
$ ip -br addr show master vrf-red
|
||||
$ ip -br addr show vrf red
|
||||
eth1 UP 10.2.1.2/24 2002:1::2/120 fe80::ff:fe00:202/64
|
||||
eth2 UP 10.2.2.2/24 2002:2::2/120 fe80::ff:fe00:203/64
|
||||
eth5 DOWN
|
||||
|
@ -241,10 +250,11 @@ for emphasis of the device type, similar to use of 'br' in bridge names.
|
|||
|
||||
To show routes for a VRF use the ip command to display the table associated
|
||||
with the VRF device:
|
||||
$ ip [-6] route show vrf NAME
|
||||
$ ip [-6] route show table ID
|
||||
|
||||
For example:
|
||||
$ ip route show table vrf-red
|
||||
$ ip route show vrf red
|
||||
prohibit default
|
||||
broadcast 10.2.1.0 dev eth1 proto kernel scope link src 10.2.1.2
|
||||
10.2.1.0/24 dev eth1 proto kernel scope link src 10.2.1.2
|
||||
|
@ -255,7 +265,7 @@ for emphasis of the device type, similar to use of 'br' in bridge names.
|
|||
local 10.2.2.2 dev eth2 proto kernel scope host src 10.2.2.2
|
||||
broadcast 10.2.2.255 dev eth2 proto kernel scope link src 10.2.2.2
|
||||
|
||||
$ ip -6 route show table vrf-red
|
||||
$ ip -6 route show vrf red
|
||||
local 2002:1:: dev lo proto none metric 0 pref medium
|
||||
local 2002:1::2 dev lo proto none metric 0 pref medium
|
||||
2002:1::/120 dev eth1 proto kernel metric 256 pref medium
|
||||
|
@ -268,23 +278,24 @@ for emphasis of the device type, similar to use of 'br' in bridge names.
|
|||
local fe80::ff:fe00:203 dev lo proto none metric 0 pref medium
|
||||
fe80::/64 dev eth1 proto kernel metric 256 pref medium
|
||||
fe80::/64 dev eth2 proto kernel metric 256 pref medium
|
||||
ff00::/8 dev vrf-red metric 256 pref medium
|
||||
ff00::/8 dev red metric 256 pref medium
|
||||
ff00::/8 dev eth1 metric 256 pref medium
|
||||
ff00::/8 dev eth2 metric 256 pref medium
|
||||
|
||||
|
||||
8. Route Lookup for a VRF
|
||||
|
||||
A test route lookup can be done for a VRF by adding the oif option to ip:
|
||||
$ ip [-6] route get oif VRF-NAME ADDRESS
|
||||
A test route lookup can be done for a VRF:
|
||||
$ ip [-6] route get vrf NAME ADDRESS
|
||||
$ ip [-6] route get oif NAME ADDRESS
|
||||
|
||||
For example:
|
||||
$ ip route get 10.2.1.40 oif vrf-red
|
||||
10.2.1.40 dev eth1 table vrf-red src 10.2.1.2
|
||||
$ ip route get 10.2.1.40 vrf red
|
||||
10.2.1.40 dev eth1 table red src 10.2.1.2
|
||||
cache
|
||||
|
||||
$ ip -6 route get 2002:1::32 oif vrf-red
|
||||
2002:1::32 from :: dev eth1 table vrf-red proto kernel src 2002:1::2 metric 256 pref medium
|
||||
$ ip -6 route get 2002:1::32 vrf red
|
||||
2002:1::32 from :: dev eth1 table red proto kernel src 2002:1::2 metric 256 pref medium
|
||||
|
||||
|
||||
9. Removing Network Interface from a VRF
|
||||
|
@ -303,46 +314,40 @@ for emphasis of the device type, similar to use of 'br' in bridge names.
|
|||
|
||||
Commands used in this example:
|
||||
|
||||
cat >> /etc/iproute2/rt_tables <<EOF
|
||||
1 vrf-mgmt
|
||||
10 vrf-red
|
||||
66 vrf-blue
|
||||
81 vrf-green
|
||||
cat >> /etc/iproute2/rt_tables.d/vrf.conf <<EOF
|
||||
1 mgmt
|
||||
10 red
|
||||
66 blue
|
||||
81 green
|
||||
EOF
|
||||
|
||||
function vrf_create
|
||||
{
|
||||
VRF=$1
|
||||
TBID=$2
|
||||
# create VRF device
|
||||
ip link add vrf-${VRF} type vrf table ${TBID}
|
||||
|
||||
# add rules that direct lookups to vrf table
|
||||
ip ru add pref 200 oif vrf-${VRF} table ${TBID}
|
||||
ip ru add pref 200 iif vrf-${VRF} table ${TBID}
|
||||
ip -6 ru add pref 200 oif vrf-${VRF} table ${TBID}
|
||||
ip -6 ru add pref 200 iif vrf-${VRF} table ${TBID}
|
||||
# create VRF device
|
||||
ip link add ${VRF} type vrf table ${TBID}
|
||||
|
||||
if [ "${VRF}" != "mgmt" ]; then
|
||||
ip route add table ${TBID} prohibit default
|
||||
ip route add table ${TBID} unreachable default
|
||||
fi
|
||||
ip link set dev vrf-${VRF} up
|
||||
ip link set dev vrf-${VRF} state up
|
||||
ip link set dev ${VRF} up
|
||||
}
|
||||
|
||||
vrf_create mgmt 1
|
||||
ip link set dev eth0 master vrf-mgmt
|
||||
ip link set dev eth0 master mgmt
|
||||
|
||||
vrf_create red 10
|
||||
ip link set dev eth1 master vrf-red
|
||||
ip link set dev eth2 master vrf-red
|
||||
ip link set dev eth5 master vrf-red
|
||||
ip link set dev eth1 master red
|
||||
ip link set dev eth2 master red
|
||||
ip link set dev eth5 master red
|
||||
|
||||
vrf_create blue 66
|
||||
ip link set dev eth3 master vrf-blue
|
||||
ip link set dev eth3 master blue
|
||||
|
||||
vrf_create green 81
|
||||
ip link set dev eth4 master vrf-green
|
||||
ip link set dev eth4 master green
|
||||
|
||||
|
||||
Interface addresses from /etc/network/interfaces:
|
||||
|
|
Загрузка…
Ссылка в новой задаче