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* bpf: Add syscall lookup support for fd array and htabMartin KaFai Lau2017-06-291-0/+5
| | | | | | | | | | | | | | | This patch allows userspace to do BPF_MAP_LOOKUP_ELEM on BPF_MAP_TYPE_PROG_ARRAY, BPF_MAP_TYPE_ARRAY_OF_MAPS and BPF_MAP_TYPE_HASH_OF_MAPS. The lookup returns a prog-id or map-id to the userspace. The userspace can then use the BPF_PROG_GET_FD_BY_ID or BPF_MAP_GET_FD_BY_ID to get a fd. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: Add array of maps supportMartin KaFai Lau2017-03-221-0/+97
This patch adds a few helper funcs to enable map-in-map support (i.e. outer_map->inner_map). The first outer_map type BPF_MAP_TYPE_ARRAY_OF_MAPS is also added in this patch. The next patch will introduce a hash of maps type. Any bpf map type can be acted as an inner_map. The exception is BPF_MAP_TYPE_PROG_ARRAY because the extra level of indirection makes it harder to verify the owner_prog_type and owner_jited. Multi-level map-in-map is not supported (i.e. map->map is ok but not map->map->map). When adding an inner_map to an outer_map, it currently checks the map_type, key_size, value_size, map_flags, max_entries and ops. The verifier also uses those map's properties to do static analysis. map_flags is needed because we need to ensure BPF_PROG_TYPE_PERF_EVENT is using a preallocated hashtab for the inner_hash also. ops and max_entries are needed to generate inlined map-lookup instructions. For simplicity reason, a simple '==' test is used for both map_flags and max_entries. The equality of ops is implied by the equality of map_type. During outer_map creation time, an inner_map_fd is needed to create an outer_map. However, the inner_map_fd's life time does not depend on the outer_map. The inner_map_fd is merely used to initialize the inner_map_meta of the outer_map. Also, for the outer_map: * It allows element update and delete from syscall * It allows element lookup from bpf_prog The above is similar to the current fd_array pattern. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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