[RFC PATCH 4/6] libbpf: support BPF_MAP_DUMP command

[Brian Vazquez]

Make libbpf aware of new BPF_MAP_DUMP command and add bpf_map_dump and
bpf_map_dump_flags to use them from the library.

Suggested-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
Signed-off-by: Brian Vazquez <brianvv@xxxxxxxxxx>
---
 tools/lib/bpf/bpf.c      | 28 ++++++++++++++++++++++++++++
 tools/lib/bpf/bpf.h      |  4 ++++
 tools/lib/bpf/libbpf.map |  2 ++
 3 files changed, 34 insertions(+)

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index c7d7993c44bb0..c1139b7db756a 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -368,6 +368,34 @@ int bpf_map_update_elem(int fd, const void *key, const void *value,
 	return sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr));
 }
 
+int bpf_map_dump(int fd, const void *prev_key, void *buf, void *buf_len)
+{
+	union bpf_attr attr;
+
+	memset(&attr, 0, sizeof(attr));
+	attr.dump.map_fd = fd;
+	attr.dump.prev_key = ptr_to_u64(prev_key);
+	attr.dump.buf = ptr_to_u64(buf);
+	attr.dump.buf_len = ptr_to_u64(buf_len);
+
+	return sys_bpf(BPF_MAP_DUMP, &attr, sizeof(attr));
+}
+
+int bpf_map_dump_flags(int fd, const void *prev_key, void *buf, void *buf_len,
+		       __u64 flags)
+{
+	union bpf_attr attr;
+
+	memset(&attr, 0, sizeof(attr));
+	attr.dump.map_fd = fd;
+	attr.dump.prev_key = ptr_to_u64(prev_key);
+	attr.dump.buf = ptr_to_u64(buf);
+	attr.dump.buf_len = ptr_to_u64(buf_len);
+	attr.dump.flags = flags;
+
+	return sys_bpf(BPF_MAP_DUMP, &attr, sizeof(attr));
+}
+
 int bpf_map_lookup_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 ff42ca043dc8f..86496443440e9 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -112,6 +112,10 @@ LIBBPF_API int bpf_verify_program(enum bpf_prog_type type,
 LIBBPF_API int bpf_map_update_elem(int fd, const void *key, const void *value,
 				   __u64 flags);
 
+LIBBPF_API int bpf_map_dump(int fd, const void *prev_key, void *buf,
+				void *buf_len);
+LIBBPF_API int bpf_map_dump_flags(int fd, const void *prev_key, void *buf,
+				void *buf_len, __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);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 2c6d835620d25..e7641773cfb0f 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -173,4 +173,6 @@ LIBBPF_0.0.4 {
 		btf__parse_elf;
 		bpf_object__load_xattr;
 		libbpf_num_possible_cpus;
+		bpf_map_dump;
+		bpf_map_dump_flags;
 } LIBBPF_0.0.3;
-- 
2.22.0.410.gd8fdbe21b5-goog