[PATCH bpf-next v2 4/5] libbpf: Add syscall wrappers for BPF_PROG_CHAIN_* commands

["Toke Høiland-Jørgensen" <toke@redhat.com>]

From: Toke Høiland-Jørgensen <toke@redhat.com>

This adds simple syscall wrappers for the new BPF_PROG_CHAIN_* commands to
libbpf.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
 tools/lib/bpf/bpf.c      |   34 ++++++++++++++++++++++++++++++++++
 tools/lib/bpf/bpf.h      |    4 ++++
 tools/lib/bpf/libbpf.map |    3 +++
 3 files changed, 41 insertions(+)

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index cbb933532981..23246fa169e7 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -703,3 +703,37 @@ int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf, __u32 *buf_len,
 
 	return err;
 }
+
+int bpf_prog_chain_add(int prev_prog_fd, __u32 retcode, int next_prog_fd) {
+	union bpf_attr attr = {};
+
+	attr.prev_prog_fd = prev_prog_fd;
+	attr.next_prog_fd = next_prog_fd;
+	attr.retcode = retcode;
+
+	return sys_bpf(BPF_PROG_CHAIN_ADD, &attr, sizeof(attr));
+}
+
+int bpf_prog_chain_del(int prev_prog_fd, __u32 retcode) {
+	union bpf_attr attr = {};
+
+	attr.prev_prog_fd = prev_prog_fd;
+	attr.retcode = retcode;
+
+	return sys_bpf(BPF_PROG_CHAIN_DEL, &attr, sizeof(attr));
+}
+
+int bpf_prog_chain_get(int prev_prog_fd, __u32 retcode, __u32 *prog_id) {
+	union bpf_attr attr = {};
+	int err;
+
+	attr.prev_prog_fd = prev_prog_fd;
+	attr.retcode = retcode;
+
+	err = sys_bpf(BPF_PROG_CHAIN_GET, &attr, sizeof(attr));
+
+	if (!err)
+		*prog_id = attr.next_prog_id;
+
+	return err;
+}
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 0db01334740f..0300cb8c8bed 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -171,6 +171,10 @@ LIBBPF_API int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf,
 				 __u32 *buf_len, __u32 *prog_id, __u32 *fd_type,
 				 __u64 *probe_offset, __u64 *probe_addr);
 
+LIBBPF_API int bpf_prog_chain_add(int prev_prog_fd, __u32 retcode, int next_prog_fd);
+LIBBPF_API int bpf_prog_chain_del(int prev_prog_fd, __u32 retcode);
+LIBBPF_API int bpf_prog_chain_get(int prev_prog_fd, __u32 retcode, __u32 *prog_id);
+
 #ifdef __cplusplus
 } /* extern "C" */
 #endif
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 8d10ca03d78d..9c483c554054 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -192,4 +192,7 @@ LIBBPF_0.0.5 {
 } LIBBPF_0.0.4;
 
 LIBBPF_0.0.6 {
+		bpf_prog_chain_add;
+		bpf_prog_chain_del;
+		bpf_prog_chain_get;
 } LIBBPF_0.0.5;