On Fri, Dec 17, 2021 at 07:20:28AM +0530, Kumar Kartikeya Dwivedi wrote: > This change adds conntrack lookup helpers using the unstable kfunc call > interface for the XDP and TC-BPF hooks. The primary usecase is > implementing a synproxy in XDP, see Maxim's patchset at [0]. > > Export get_net_ns_by_id as nf_conntrack needs to call it. > > Note that we search for acquire, release, and null returning kfuncs in > the intersection of those sets and main set. > > This implies that the kfunc_btf_id_list acq_set, rel_set, null_set may > contain BTF ID not in main set, this is explicitly allowed and > recommended (to save on definining more and more sets), since > check_kfunc_call verifier operation would filter out the invalid BTF ID > fairly early, so later checks for acquire, release, and ret_type_null > kfunc will only consider allowed BTF IDs for that program that are > allowed in main set. This is why the nf_conntrack_acq_ids set has BTF > IDs for both xdp and tc hook kfuncs. > > [0]: https://lore.kernel.org/bpf/20211019144655.3483197-1-maximmi@xxxxxxxxxx > > Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx> > --- > include/linux/btf.h | 2 + > kernel/bpf/btf.c | 1 + > net/core/filter.c | 24 +++ > net/core/net_namespace.c | 1 + > net/netfilter/nf_conntrack_core.c | 278 ++++++++++++++++++++++++++++++ Toke proposed to move it to net/netfilter/nf_conntrack_bpf.c
