Lack of support for SRv6 static-sids programming in sonic-buildimage master

[BYGX-wcr]

In the current SRv6 implementation of FRR, the SRv6 SIDS are programmed into the data-plane via kernel netlink messages because in Linux kernel SRv6 SIDS are treated as if they are IP routes. Since the interface attribute field is mandatory for every netlink message, FRR by default assumes that there is a sr0 interface available and it will use sr0 for the netlink messages that carry the SRv6 static SIDs.

So, to enable FRR to program static SRv6 SIDs, we added code to create the dummy interface "sr0" upon system startup in SONiC msft-202412 images(Azure/sonic-buildimage-msft#517). However, this code is not available in SONiC master because people are looking for better solutions such as kernel bypassing in SRv6 SIDs programming. To make the SRv6 feature publicly available for the community in 202505 SONiC release, I created this issue to track the progress in developing the solution for the aforementioned problem.

[BYGX-wcr]

@ahsalam, @cscarpitta, @eddieruan-alibaba, we need to pay attention to this issue if we want to get the static-sids feature available in 202505 image

[BYGX-wcr]

@lguohan, @rlhui, @abdosi

[eddieruan-alibaba]

@zice312963205 @GaladrielZhao

[ahsalam]

@ahsalam, @cscarpitta, @eddieruan-alibaba, we need to pay attention to this issue if we want to get the static-sids feature available in 202505 image

@BYGX-wcr Carmine and I working on this. We will update here.