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This is an implementation of PBR for FRR.
This implemenation uses a combination of rules and
tables to determine how packets will flow.
PBR introduces a new concept of 'nexthop-groups' to
specify a group of nexthops that will be used for
ecmp. Nexthop-groups are specified on the cli via:
nexthop-group DONNA
nexthop 192.168.208.1
nexthop 192.168.209.1
nexthop 192.168.210.1
!
PBR sees the nexthop-group and installs these as a default
route with these nexthops starting at table 10000
robot# show pbr nexthop-groups
Nexthop-Group: DONNA Table: 10001 Valid: 1 Installed: 1
Valid: 1 nexthop 192.168.209.1
Valid: 1 nexthop 192.168.210.1
Valid: 1 nexthop 192.168.208.1
I have also introduced the ability to specify a table
in a 'show ip route table XXX' to see the specified tables.
robot# show ip route table 10001
Codes: K - kernel route, C - connected, S - static, R - RIP,
O - OSPF, I - IS-IS, B - BGP, P - PIM, E - EIGRP, N - NHRP,
T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
F - PBR,
> - selected route, * - FIB route
F>* 0.0.0.0/0 [0/0] via 192.168.208.1, enp0s8, 00:14:25
* via 192.168.209.1, enp0s9, 00:14:25
* via 192.168.210.1, enp0s10, 00:14:25
PBR tracks PBR-MAPS via the pbr-map command:
!
pbr-map EVA seq 10
match src-ip 4.3.4.0/24
set nexthop-group DONNA
!
pbr-map EVA seq 20
match dst-ip 4.3.5.0/24
set nexthop-group DONNA
!
pbr-maps can have 'match src-ip <prefix>' and 'match dst-ip <prefix>'
to affect decisions about incoming packets. Additionally if you
only have one nexthop to use for a pbr-map you do not need
to setup a nexthop-group and can specify 'set nexthop XXXX'.
To apply the pbr-map to an incoming interface you do this:
interface enp0s10
pbr-policy EVA
!
When a pbr-map is applied to interfaces it can be installed
into the kernel as a rule:
[sharpd@robot frr1]$ ip rule show
0: from all lookup local
309: from 4.3.4.0/24 iif enp0s10 lookup 10001
319: from all to 4.3.5.0/24 iif enp0s10 lookup 10001
1000: from all lookup [l3mdev-table]
32766: from all lookup main
32767: from all lookup default
[sharpd@robot frr1]$ ip route show table 10001
default proto pbr metric 20
nexthop via 192.168.208.1 dev enp0s8 weight 1
nexthop via 192.168.209.1 dev enp0s9 weight 1
nexthop via 192.168.210.1 dev enp0s10 weight 1
The linux kernel now will use the rules and tables to properly
apply these policies.
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
Signed-off-by: Don Slice <dslice@cumulusnetworks.com>
Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>
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