docs: networking: convert vrf.txt to ReST

- add SPDX header;
- adjust title markup;
- Add a subtitle for the first section;
- mark code blocks and literals as such;
- adjust identation, whitespaces and blank lines;
- add to networking/index.rst.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/index.rst

@@ -113,6 +113,7 @@ Contents:
    tproxy
    tuntap
    udplite
+   vrf
 
 .. only::  subproject and html
 

Documentation/networking/vrf.txt → Documentation/networking/vrf.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+====================================
 Virtual Routing and Forwarding (VRF)
 ====================================
+
+The VRF Device
+==============
+
 The VRF device combined with ip rules provides the ability to create virtual
 routing and forwarding domains (aka VRFs, VRF-lite to be specific) in the
 Linux network stack. One use case is the multi-tenancy problem where each
@@ -22,7 +29,7 @@ and then VRF devices provide L3 separation.
 Design
 ------
 A VRF device is created with an associated route table. Network interfaces
-are then enslaved to a VRF device:
+are then enslaved to a VRF device::
 
 	 +-----------------------------+
 	 |           vrf-blue          |  ===> route table 10
@@ -41,15 +48,15 @@ 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.
+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
+.. [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 supports PREROUTING with skb->dev set to the real
+.. [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.
@@ -57,7 +64,9 @@ as a whole.
 Setup
 -----
 1. VRF device is created with an association to a FIB table.
-   e.g, ip link add vrf-blue type vrf table 10
+   e.g,::
+
+	ip link add vrf-blue type vrf table 10
 	ip link set dev vrf-blue up
 
 2. An l3mdev FIB rule directs lookups to the table associated with the device.
@@ -66,11 +75,13 @@ Setup
    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:
+   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
 
-3. Set the default route for the table (and hence default route for the VRF).
+3. Set the default route for the table (and hence default route for the VRF)::
+
        ip route add table 10 unreachable default metric 4278198272
 
    This high metric value ensures that the default unreachable route can
@@ -78,7 +89,8 @@ Setup
    kernel metrics as a combined admin distance (upper byte) and priority
    (lower 3 bytes).  Thus the above metric translates to [255/8192].
 
-4. Enslave L3 interfaces to a VRF device.
+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
@@ -87,17 +99,19 @@ Setup
    FIB table following the enslavement.
 
    The IPv6 sysctl option keep_addr_on_down can be enabled to keep IPv6 global
-   addresses as VRF enslavement changes.
+   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.
+5. Additional VRF routes are added to associated table::
+
        ip route add table 10 ...
 
 
 Applications
 ------------
 Applications that are to work within a VRF need to bind their socket to the
-VRF device:
+VRF device::
 
     setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, dev, strlen(dev)+1);
 
@@ -110,7 +124,7 @@ the same port if they bind to an l3mdev.
 
 TCP & UDP 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 and udp_l3mdev_accept sysctl options:
+tcp_l3mdev_accept and udp_l3mdev_accept sysctl options::
 
     sysctl -w net.ipv4.tcp_l3mdev_accept=1
     sysctl -w net.ipv4.udp_l3mdev_accept=1
@@ -123,14 +137,14 @@ using a socket not bound to the corresponding VRF. This allows e.g. older ping
 implementations to be run with specifying the device but without executing it
 in the VRF. This option can be disabled so that packets received in a VRF
 context are only handled by a raw socket bound to the VRF, and packets in the
-default VRF are only handled by a socket not bound to any VRF:
+default VRF are only handled by a socket not bound to any VRF::
 
     sysctl -w net.ipv4.raw_l3mdev_accept=0
 
 netfilter rules on the VRF device can be used to limit access to services
 running in the default VRF context as well.
 
-################################################################################
+--------------------------------------------------------------------------------
 
 Using iproute2 for VRFs
 =======================
@@ -140,7 +154,8 @@ older form without it.
 
 1. Create a VRF
 
-   To instantiate a VRF device and associate it with a table:
+   To instantiate a VRF device and associate it with a table::
+
        $ ip link add dev NAME type vrf table ID
 
    As of v4.8 the kernel supports the l3mdev FIB rule where a single rule
@@ -149,11 +164,13 @@ older form without it.
 
 2. List VRFs
 
-   To list VRFs that have been created:
+   To list VRFs that have been created::
+
        $ ip [-d] link show type vrf
 	 NOTE: The -d option is needed to show the table id
 
-   For example:
+   For example::
+
        $ ip -d link show type vrf
        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
@@ -169,7 +186,7 @@ older form without it.
 	   vrf table 81 addrgenmode eui64
 
 
-   Or in brief output:
+   Or in brief output::
 
        $ ip -br link show type vrf
        mgmt         UP             72:b3:ba:91:e2:24 <NOARP,MASTER,UP,LOWER_UP>
@@ -181,24 +198,28 @@ older form without it.
 3. Assign a Network Interface to a VRF
 
    Network interfaces are assigned to a VRF by enslaving the netdevice to a
-   VRF device:
+   VRF device::
+
        $ 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:
+   For example::
+
        $ 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:
+   option to the ip command::
+
        $ ip link show vrf NAME
        $ ip link show master NAME
 
-   For example:
+   For example::
+
        $ 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
@@ -208,7 +229,8 @@ older form without it.
 	   link/ether 02:00:00:00:02:06 brd ff:ff:ff:ff:ff:ff
 
 
-   Or using the brief output:
+   Or using the brief output::
+
        $ ip -br link show vrf 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>
@@ -218,11 +240,13 @@ older form without it.
 5. Show Neighbor Entries for a VRF
 
    To list neighbor entries associated with devices enslaved to a VRF device
-   add the master option to the ip command:
+   add the master option to the ip command::
+
        $ ip [-6] neigh show vrf NAME
        $ ip [-6] neigh show master NAME
 
-   For example:
+   For example::
+
        $  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
@@ -234,11 +258,13 @@ older form without it.
 6. Show Addresses for a VRF
 
    To show addresses for interfaces associated with a VRF add the master
-   option to the ip command:
+   option to the ip command::
+
        $ ip addr show vrf NAME
        $ ip addr show master NAME
 
-   For example:
+   For example::
+
 	$ 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
@@ -259,7 +285,8 @@ older form without it.
 	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:
+   Or in brief format::
+
 	$ 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
@@ -269,11 +296,13 @@ older form without it.
 7. Show Routes for a VRF
 
    To show routes for a VRF use the ip command to display the table associated
-   with the VRF device:
+   with the VRF device::
+
        $ ip [-6] route show vrf NAME
        $ ip [-6] route show table ID
 
-   For example:
+   For example::
+
 	$ ip route show vrf red
 	unreachable default  metric 4278198272
 	broadcast 10.2.1.0 dev eth1  proto kernel  scope link  src 10.2.1.2
@@ -305,11 +334,13 @@ older form without it.
 
 8. Route Lookup for a VRF
 
-   A test route lookup can be done for a VRF:
+   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:
+   For example::
+
 	$ ip route get 10.2.1.40 vrf red
 	10.2.1.40 dev eth1  table red  src 10.2.1.2
 	    cache
@@ -321,28 +352,30 @@ older form without it.
 9. Removing Network Interface from a VRF
 
    Network interfaces are removed from a VRF by breaking the enslavement to
-   the VRF device:
+   the VRF device::
+
        $ ip link set dev NAME nomaster
 
    Connected routes are moved back to the default table and local entries are
    moved to the local table.
 
-   For example:
+   For example::
+
     $ ip link set dev eth0 nomaster
 
 --------------------------------------------------------------------------------
 
-Commands used in this example:
+Commands used in this example::
 
-cat >> /etc/iproute2/rt_tables.d/vrf.conf <<EOF
-1  mgmt
-10 red
-66 blue
-81 green
-EOF
+     cat >> /etc/iproute2/rt_tables.d/vrf.conf <<EOF
+     1  mgmt
+     10 red
+     66 blue
+     81 green
+     EOF
 
-function vrf_create
-{
+     function vrf_create
+     {
 	 VRF=$1
 	 TBID=$2
 
@@ -353,66 +386,66 @@ function vrf_create
 	     ip route add table ${TBID} unreachable default metric 4278198272
 	 fi
 	 ip link set dev ${VRF} up
-}
+     }
 
-vrf_create mgmt 1
-ip link set dev eth0 master mgmt
+     vrf_create mgmt 1
+     ip link set dev eth0 master mgmt
 
-vrf_create red 10
-ip link set dev eth1 master red
-ip link set dev eth2 master red
-ip link set dev eth5 master red
+     vrf_create red 10
+     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 blue
+     vrf_create blue 66
+     ip link set dev eth3 master blue
 
-vrf_create green 81
-ip link set dev eth4 master green
+     vrf_create green 81
+     ip link set dev eth4 master green
 
 
-Interface addresses from /etc/network/interfaces:
-auto eth0
-iface eth0 inet static
+     Interface addresses from /etc/network/interfaces:
+     auto eth0
+     iface eth0 inet static
 	   address 10.0.0.2
 	   netmask 255.255.255.0
 	   gateway 10.0.0.254
 
-iface eth0 inet6 static
+     iface eth0 inet6 static
 	   address 2000:1::2
 	   netmask 120
 
-auto eth1
-iface eth1 inet static
+     auto eth1
+     iface eth1 inet static
 	   address 10.2.1.2
 	   netmask 255.255.255.0
 
-iface eth1 inet6 static
+     iface eth1 inet6 static
 	   address 2002:1::2
 	   netmask 120
 
-auto eth2
-iface eth2 inet static
+     auto eth2
+     iface eth2 inet static
 	   address 10.2.2.2
 	   netmask 255.255.255.0
 
-iface eth2 inet6 static
+     iface eth2 inet6 static
 	   address 2002:2::2
 	   netmask 120
 
-auto eth3
-iface eth3 inet static
+     auto eth3
+     iface eth3 inet static
 	   address 10.2.3.2
 	   netmask 255.255.255.0
 
-iface eth3 inet6 static
+     iface eth3 inet6 static
 	   address 2002:3::2
 	   netmask 120
 
-auto eth4
-iface eth4 inet static
+     auto eth4
+     iface eth4 inet static
 	   address 10.2.4.2
 	   netmask 255.255.255.0
 
-iface eth4 inet6 static
+     iface eth4 inet6 static
 	   address 2002:4::2
 	   netmask 120

MAINTAINERS

@@ -18106,7 +18106,7 @@ M:	David Ahern <dsahern@kernel.org>
 M:	Shrijeet Mukherjee <shrijeet@gmail.com>
 L:	netdev@vger.kernel.org
 S:	Maintained
-F:	Documentation/networking/vrf.txt
+F:	Documentation/networking/vrf.rst
 F:	drivers/net/vrf.c
 
 VSPRINTF