On 4/27/20 12:49 PM, Sowmini Varadhan wrote:
The iproute2 BPF-loader does not support BTF. I think upstream agrees that it would be too much work to add (and maintain) it, so the current plan[1] is to convert iproute2 to use libbpf instead.
Not true, iproute2 does(did) support BTF, but afaik later versions of clang/ llvm broke it so it would need to be fixed again [0]. Emission of BTF can be removed as a workaround w/ omitting -g. [0] https://git.kernel.org/pub/scm/network/iproute2/iproute2.git/commit/?id=f823f36012fb5ab4ddfca6ed4ff56188730f281e
So I updated my iproute2 because I was initially getting an error like " Error fixing up map structure, incompatible struct bpf_elf_map used? Error fetching ELF ancillary data! Unable to load program " with the native iproute2 binaries, and thought it may be due to a header mismatch.Why do you want to use 'tc' to load XDP?I was merely using the exsiting example in samples to try to understand this. If the existing example is misleading, it should be removed.I actually think this is only a warning, and the program is actually loaded...no I dont believe it is. if you insert a break in the script before it gets to cleanup, and try # ip netns exec ns2 bash # tc filter show dev vens2 it will not show any loaded filters.
Check out https://cilium.readthedocs.io/en/latest/bpf/#iproute2 for XDP + iproute2 examples examples for where to check; but agree you might rather want to go with libbpf's feature set overall.
--Sowmini
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