net: Replace ifname check with IFF_LOOPBACK in Discover #29984
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Checking the interface name is kind of brittle. In the age of network namespaces and containers, there is no reason a loopback interface can't be called differently. Check for the `IFF_LOOPBACK` flag to detect loopback interface instead.
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All network addresses are being iterated over and added, not just the first one per interface.
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utACK a68fed1 |
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Agree this will be less brittle than name-checking. I don't think it's possible that IFF_LOOPBACK would ever be unset for a loopback device unless someone had modified their kernel.
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post-merge ACK a68fed1 Interestingly, libpcap still implements both the "brittle" and the |
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Thanks for checking! it's kind of a belt-and-suspenders check: we only look for routable addresses in Discover, so unless someone assigned a routable address to the loopback interface-which would be really strange-it doesn't actually influence the result. |
Checking the interface name is kind of brittle. In the age of network namespaces and containers, there is no reason a loopback interface can't be called differently.
Check for the
IFF_LOOPBACKflag to detect loopback interface instead.Also remove a misleading comment in Discover's doc comment.