libbpf: introduce bpf_map_lookup_elem_flags()

Introduce
int bpf_map_lookup_elem_flags(int fd, const void *key, void *value, __u64 flags)
helper to lookup array/hash/cgroup_local_storage elements with BPF_F_LOCK flag.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

3 files changed, 16 insertions, 0 deletions

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 88cbd110ae58..3defad77dc7a 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -368,6 +368,19 @@ int bpf_map_lookup_elem(int fd, const void *key, void *value)
         return sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr));
 }
 
+int bpf_map_lookup_elem_flags(int fd, const void *key, void *value, __u64 flags)
+{
+        union bpf_attr attr;
+
+        bzero(&attr, sizeof(attr));
+        attr.map_fd = fd;
+        attr.key = ptr_to_u64(key);
+        attr.value = ptr_to_u64(value);
+        attr.flags = flags;
+
+        return sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr));
+}
+
 int bpf_map_lookup_and_delete_elem(int fd, const void *key, void *value)
 {
         union bpf_attr attr;
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 8f09de482839..ed09eed2dc3b 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -110,6 +110,8 @@ LIBBPF_API int bpf_map_update_elem(int fd, const void *key, const void *value,
                                    __u64 flags);
 
 LIBBPF_API int bpf_map_lookup_elem(int fd, const void *key, void *value);
+LIBBPF_API int bpf_map_lookup_elem_flags(int fd, const void *key, void *value,
+                                         __u64 flags);
 LIBBPF_API int bpf_map_lookup_and_delete_elem(int fd, const void *key,
                                               void *value);
 LIBBPF_API int bpf_map_delete_elem(int fd, const void *key);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 266bc95d0142..f6f96fc38c50 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -130,4 +130,5 @@ LIBBPF_0.0.2 {
                 bpf_probe_helper;
                 bpf_probe_map_type;
                 bpf_probe_prog_type;
+                bpf_map_lookup_elem_flags;
 } LIBBPF_0.0.1;