bpf: btf: Add BTF support to libbpf

If the ".BTF" elf section exists, libbpf will try to create
a btf_fd (through BPF_BTF_LOAD).  If that fails, it will still
continue loading the bpf prog/map without the BTF.

If the bpf_object has a BTF loaded, it will create a map with the btf_fd.
libbpf will try to figure out the btf_key_id and btf_value_id of a map by
finding the BTF type with name "<map_name>_key" and "<map_name>_value".
If they cannot be found, it will continue without using the BTF.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 16 insertions, 0 deletions

diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 39f6a0d64a3b..01bda076310f 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -26,6 +26,20 @@
 #include <linux/bpf.h>
 #include <stddef.h>
 
+struct bpf_create_map_attr {
+        const char *name;
+        enum bpf_map_type map_type;
+        __u32 map_flags;
+        __u32 key_size;
+        __u32 value_size;
+        __u32 max_entries;
+        __u32 numa_node;
+        __u32 btf_fd;
+        __u32 btf_key_id;
+        __u32 btf_value_id;
+};
+
+int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr);
 int bpf_create_map_node(enum bpf_map_type map_type, const char *name,
                         int key_size, int value_size, int max_entries,
                         __u32 map_flags, int node);
@@ -87,4 +101,6 @@ int bpf_obj_get_info_by_fd(int prog_fd, void *info, __u32 *info_len);
 int bpf_prog_query(int target_fd, enum bpf_attach_type type, __u32 query_flags,
                    __u32 *attach_flags, __u32 *prog_ids, __u32 *prog_cnt);
 int bpf_raw_tracepoint_open(const char *name, int prog_fd);
+int bpf_load_btf(void *btf, __u32 btf_size, char *log_buf, __u32 log_buf_size,
+                 bool do_log);
 #endif