[sonic-cfggen][FRR] Support T2 chassis frontend

[baiwei0427]

- What I did

Support new role: T2 chassis frontend switch (SpineChassisFrontendRouter). The chassis frontend switch needs BGP-EVPN, Vxlan and Vnet support.

- How I did it

• Modify minigraph parser to add Vnet and Vxlan informration for T2 chassis frontend

• Add new bgpd and zebra j2 templates to support BGP-EVPN

• Add new tests to sonic-cfggen unit test scripts

- How to verify it

Run load_minigraph and verify entries in config DB and FRR configuration.

In config DB, you should be able to see the following entries:

"VNET|VnetFE"
"VXLAN_TUNNEL|TunnelInt"

In FRR docker, you should be able to see BGP-EVPN configuration like follows:

router bgp 4000 vrf VnetFE
  no bgp default ipv4-unicast
  bgp log-neighbor-changes
  bgp bestpath as-path multipath-relax
  no bgp default ipv4-unicast
  bgp graceful-restart restart-time 240
  bgp graceful-restart
  bgp router-id 4.0.0.0
  neighbor 192.168.0.1 remote-as 3000
  neighbor 192.168.0.1 description Leaf01
  neighbor 192.168.0.1 timers 3 10
  address-family ipv4 unicast
    neighbor 192.168.0.1 activate
    neighbor 192.168.0.1 soft-reconfiguration inbound
    maximum-paths 64
  exit-address-family
  address-family l2vpn evpn
    advertise ipv4 unicast
  exit-address-family

!
! bgp multiple-instance
!
route-map FROM_BGP_SPEAKER_V4 permit 10
!
route-map TO_BGP_SPEAKER_V4 deny 10
!
router bgp 4000
  bgp log-neighbor-changes
  bgp bestpath as-path multipath-relax
  no bgp default ipv4-unicast
  bgp graceful-restart restart-time 240
  bgp graceful-restart
  bgp router-id 4.0.0.0
  network 4.0.0.0/32
  neighbor 4.0.0.1 remote-as 4000
  neighbor 4.0.0.1 description SpineFront02
  neighbor 4.0.0.1 timers 3 10
  address-family l2vpn evpn
    neighbor 4.0.0.1 activate
    advertise-all-vni
  exit-address-family
  neighbor 172.16.0.2 remote-as 5000
  neighbor 172.16.0.2 description SpineBack01
  neighbor 172.16.0.2 timers 3 10
  address-family ipv4 unicast
    neighbor 172.16.0.2 allowas-in 1
    neighbor 172.16.0.2 activate
    neighbor 172.16.0.2 soft-reconfiguration inbound
    maximum-paths 64
  exit-address-family
  neighbor 172.16.0.10 remote-as 5000
  neighbor 172.16.0.10 description SpineBack02
  neighbor 172.16.0.10 timers 3 10
  address-family ipv4 unicast
    neighbor 172.16.0.10 allowas-in 1
    neighbor 172.16.0.10 activate
    neighbor 172.16.0.10 soft-reconfiguration inbound
    maximum-paths 64
  exit-address-family
!
maximum-paths 64
!
route-map ISOLATE permit 10
set as-path prepend 4000
!
route-map set-next-hop-global-v6 permit 10
set ipv6 next-hop prefer-global
!

- Description for the changelog

- A picture of a cute animal (not mandatory but encouraged)

Signed-off-by: Wei Bai baiwei0427@gmail.com and Ze Gan ganze718@gmail.com

[lguohan]

isinstance [](start = 11, length = 10)

use this function.

def is_ip_prefix_in_key(self, key):
    '''
    Function to check if IP address is present in the key. If it
    is present, then the key would be a tuple or else, it shall be
    be string
    '''
    return (isinstance(key, tuple))

[lguohan]

for better code readability, we need to directly understand the intention of the code without guessing.

[baiwei0427]

@lguohan Fixed

[lguohan]

why do we need to check if pc_member is a tuple or not?

[baiwei0427]

@lguohan I check https://github.com/Azure/SONiC/wiki/Configuration#port-channel-member. It seems that pc_member must be a tuple (port channel, physical interface). So I remove check here.

[stcheng]

i'd suppose it is better to separate the t2 chassis tests into one separate test file since it introduces many new features

[baiwei0427]

@stcheng Fixed

[baiwei0427]

retest this please

[baiwei0427]

retest this please

[stcheng]

thanks!