Usage¶

In this section, it is assumed that Virtual Accelerator has been properly installed and configured. See Getting Started for more details.

Managing GRE interfaces from the fast path¶

The fp-cli commands below allow you to manage GRE interfaces.

To start fp-cli, enter:
```
$ fp-cli
```

Displaying GRE interfaces¶

Synopsis

gre [name IFNAME]

IFNAME

Name of the GRE interface.

Example

<fp-0> gre
gre1-vr0 linked to eth1-vr0 link vrfid: 0
    mode IP
    local: 2.0.0.1 remote: 2.0.0.5
    ttl: 64 tos: 0x02
    iflags: csum key oflags: csum key
    ikey: 0x00000001 (1)
    okey: 0x00000001 (1)

Displaying GRE statistics¶

Synopsis

gre-stats [percore] [all]

Parameters

percore: Display all statistics per core running the fast path.
all: Display all statistics (even those that are null).

Example

<fp-0> gre-stats all
GREDroppedParseIPv4HeaderFailure:0
GREDroppedParseIPv6HeaderFailure:0
GREDroppedPullupIPv4HeaderFailure:0
GREDroppedMissingChecksum:0
GREDroppedUnexpectedChecksum:0
GREDroppedWrongChecksum:0
GREDroppedInitGreIPv4HeaderFailure:0
GREDroppedInitIPv4HeaderFailure:0
GREDroppedPullupIPv6HeaderFailure:0
GREDroppedInitGreIPv6HeaderFailure:0
GREDroppedInitIPv6HeaderFailure:0
GREExceptionInputUnsupportedProtocol:0
GREExceptionOutputUnsupportedProtocol:0
GREExceptionUnsupportedEtherType:0
GREExceptionUnknownIface:0
GREExceptionIPv4Route:0
GREExceptionIPv6Route:0
GREExceptionIPv4SourceSelectFailed:0
GREInvalidHeader:0
GREProtocolNotSupported:0

The output is available in JSON format as well.

Synopsis

gre-stats-son

<fp-0> gre-stats-json
{
  "GREDroppedParseIPv4HeaderFailure": 0,
  "GREDroppedParseIPv6HeaderFailure": 0,
  "GREDroppedPullupIPv4HeaderFailure": 0,
  "GREDroppedPullupIPv6HeaderFailure": 0,
  "GREExceptionUnknownIface": 0,
  "GREDroppedUnexpectedChecksum": 0,
  "GREDroppedWrongChecksum": 0,
  "GREDroppedMissingChecksum": 0,
  "GREExceptionUnsupportedEtherType": 0,
  "GREDroppedInitGreIPv4HeaderFailure": 0,
  "GREDroppedInitIPv4HeaderFailure": 0,
  "GREDroppedInitGreIPv6HeaderFailure": 0,
  "GREDroppedInitIPv6HeaderFailure": 0,
  "GREExceptionInputUnsupportedProtocol": 0,
  "GREExceptionOutputUnsupportedProtocol": 0,
  "GREExceptionIPv4Route": 0,
  "GREInvalidHeader": 0,
  "GREProtocolNotSupported": 0,
  "GREExceptionIPv6Route": 0,
  "GREExceptionIPv4SourceSelectFailed": 0,
}

Simple GRE L3 tunnel¶

We will assume the network topology is the following:

            +---------------+                +---------------+
            |    Remote     |                | Gateway  with |
            |    Gateway    |                |   fast path   |
            |               |2.0.0.5         |               |
<-<---------|-ethY   /-ethX-|================|-eth1-\   eth2-|--------->->
  100.2.2.1 |     greZ      |         2.0.0.1|      gre1     | 110.2.2.1
            |  10.10.10.2   |                |   10.10.10.1  |
            |               |                |               |
            +---------------+                +---------------+

Configure IP addresses and routes:

# ip link set eth1 up
# ip addr add 2.0.0.1/24 dev eth1
# ip link set eth2 up
# ip addr add 110.2.2.1/24 dev eth2

Create a new GRE interface:

# ip tunnel add gre1 mode gre local 2.0.0.1 remote 2.0.0.5 dev eth1 key 1 csum
# ip link set gre1 up
# ip addr add 10.10.10.1 peer 10.10.10.2/24 dev gre1

Create a new route:

# ip route add 100.2.2.1 via 10.10.10.2

Display the characteristics of GRE interfaces on the fast path:

$ fp-cli

<fp-0> gre
gre1-vr0 linked to eth1-vr0 link vrfid: 0
    mode IP
    local: 2.0.0.1 remote: 2.0.0.5
    ttl: inherit tos: 0x00
    iflags: csum key oflags: csum key
    ikey: 0x00000001 (1)
    okey: 0x00000001 (1)

Simple GRE L2 tunnel¶

We will assume the network topology is the following:

            +---------------+                +---------------+
            |    Remote     |                | Gateway  with |
            |    Gateway    |                |   fast path   |
            |               |2.0.0.5         |               |
<-<---------|-ethY   /-ethX-|================|-eth1-\   eth2-|--------->->
  100.2.2.1 |   gretapZ     |         2.0.0.1|    gretap1    | 110.2.2.1
            |  10.10.10.2   |                |   10.10.10.1  |
            |               |                |               |
            +---------------+                +---------------+

Configure IP addresses and routes:

# ip link set eth1 up
# ip addr add 2.0.0.1/24 dev eth1
# ip link set eth2 up
# ip addr add 110.2.2.1/24 dev eth2

Create a new GRE interface:

# ip link add name gretap1 type gretap local 2.0.0.1 remote 2.0.0.5 dev eth1 key 1 csum
# ip link set gretap1 up
# ip addr add 10.10.10.1/24 dev gretap1

Create a new route:

# ip route add 100.2.2.1 via 10.10.10.2

Display the characteristics of GRE interfaces on the fast path:

$ fp-cli

<fp-0> gre
gre1-vr0 linked to eth1-vr0 link vrfid: 0
    mode Ether
    local: 2.0.0.1 remote: 2.0.0.5
    ttl: inherit tos: 0x00
    iflags: csum key oflags: csum key
    ikey: 0x00000001 (1)
    okey: 0x00000001 (1)
gre_sys-vr0 linked to ifid0-vr0 link vrfid: 0 master: ovs
    mode Ether
    local: any remote: any
    ttl: inherit tos: 0x00
    iflags: oflags:

Note

GRE interfaces displaying ‘master: ovs’ will be managed by the Fast Path OVS Acceleration module. With kernel >= 4.4, a GRE interface will be created to represent Open vSwitch GRE ports.

Simple cross-vrf GRE tunnel¶

We will assume the network topology is the following:

            +---------------+                +----------------+
            |    Remote     |                | Gateway  with  |
            |    Gateway    |                |   fast path    |
            |               |                |                |
            |               |                |---------+      |
            |               |                |   vrf1  |      |
            |               |2.0.0.5         |         |      |
<-<---------|-ethY  //=ethX-|================|-eth1=\\ | eth2-|--------->->
  100.2.2.1 |       ||      |         2.0.0.1|      || |      | 110.2.2.1
            |       ||      |                |------||-+      |
            |     greZ      |                |      gre1      |
            |  10.10.10.2   |                |   10.10.10.1   |
            |               |                |                |
            +---------------+                +----------------+

The gre1 interface will use 2 VRs:

The interface link-vr, i.e. the VR of encapsulated GRE packets
The interface vr, i.e. the VR of plaintext packets

We will create the GRE interface in the link-vr interface, then move it to its own VR.

Create the vrf1 network namespace:
```
# vrfctl add 1 linux-fp-sync-vrf.sh
```

Configure IP addresses and routes:

# ip link set eth1 netns vrf1
# ip netns exec vrf1 ip link set eth1 up
# ip netns exec vrf1 ip addr add 2.0.0.1/24 dev eth1
# ip netns exec vrf0 ip link set eth2 up
# ip netns exec vrf0 ip addr add 110.2.2.1/24 dev eth2

Create a new GRE interface:

# ip netns exec vrf1 ip link add gre1 type gre local 2.0.0.1 remote 2.0.0.5
# ip netns exec vrf1 ip link set gre1 netns vrf0
# ip netns exec vrf0 ip link set gre1 up
# ip netns exec vrf0 ip addr add 10.10.10.1 peer 10.10.10.2/24 dev gre1

Create a new route:

# ip netns exec vrf0 ip route add 100.2.2.1 via 10.10.10.2

Display the characteristics of GRE interfaces on the fast path:

$ fp-cli

<fp-0> gre
gre1-vr0 linked to ifid0-vr0 link vrfid: 1
    mode IP
    local: 2.0.0.1 remote: 2.0.0.5
    ttl: inherit tos: 0x00
    iflags: oflags:

Providing options¶

Some capabilities can be tuned for this module.

--ifaces¶

Maximum number of GRE interfaces. This GRE interface can be a tunnel or a L2 tunnel over IPv4 or IPv6 (i.e. link type can be gre, gretap, ip6gre or ip6gretap)

Default value: 255
Memory footprint per GRE interfaces: 100 B
Range: 0 .. 5000

Example

FP_OPTIONS="--mod-opt=gre:--ifaces=512"

Then fast path can manage up to 512 GRE interfaces.

--hash-order-ipv4¶

Size order of GRE interfaces for tunnel (L3 or L2) over IPv4 hash table. Value automatically updated if --ifaces is changed.

Default value: 4
Range: 1 .. 31

Example

FP_OPTIONS="--mod-opt=gre:--hash-order-ipv4=10"

--hash-order-ipv6¶

Size order of GRE interfaces for tunnel (L3 or L2) over IPv6 hash table. Value automatically updated if --ifaces is changed.

Default value: 4
Range: 1 .. 31

Example

FP_OPTIONS="--mod-opt=gre:--hash-order-ipv6=10"

Tip

To get optimal performance, apply the following ratios to the three parameters:

Parameter	Value
–hash-order-ipv4	`N`
–hash-order-ipv6	`N`
–ifaces	`2 ** N`

Note

See Fast Path Capabilities documentation for impact of the available memory on the default value of configurable capabilities