T6962: frr: fix wrong kernel routes updates - #1029
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Pull Request Overview
This PR fixes an issue where FRR (Free Range Routing) incorrectly handles kernel route updates when the last IPv4 address is deleted from an interface. The Linux kernel deletes IPv4 routes when the last interface IPv4 address is removed but doesn't send RTM_DELROUTE notifications, causing FRR's routing table to become out of sync with the kernel.
Key changes:
- Adds new enum value
RIB_UPDATE_KERNEL_LAST_ADDRESS_DELETEDfor tracking last address deletion events - Implements function
if_has_connected_with_family()to check for addresses of a specific family on an interface - Updates route handling logic to properly detect and handle last IPv4 address deletion scenarios
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sever-sever
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Fix for zebra to for updated kernel routes
The patch 0007-zebra-remove-kernel-route-on-last-address-deletion.patch fixes root cause of the issue: Zebra didn't do anything on last IPv4 address deletion though kernel in such case deletes all IPv4 routes. FRR PR: FRRouting/frr#19564
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dmbaturin
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I trust Kyrylo's and Viacheslav's judgement and the code looks good to me.
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FRR: Fix wrong kernel routes updates
The patch 0007-zebra-remove-kernel-route-on-last-address-deletion.patch fixes root cause of the issue: Zebra didn't do anything on last IPv4 address deletion though kernel in such case deletes all IPv4 routes.
FRR PR: FRRouting/frr#19564
I'm pretty confident in the patch, I've added topotest case, PR passed almost all topotests (I've checked that failed ones fail in other PRs as well and they really seem to have nothing to do with my changes).
As the issue is non-critical we can wait for FRR reaction to be sure not to break something.
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