[bpf-next,v2,26/28] libbpf: add handling for BPF_F_INSERT_HEAD in HID programs

Commit Message

Benjamin Tissoires March 4, 2022, 5:28 p.m. UTC

Export the newly created flag to libbpf.

Signed-off-by: Benjamin Tissoires <[e-mail]>

---

new in v2
---
 tools/include/uapi/linux/bpf.h | 10 ++++++++++
 tools/lib/bpf/libbpf.c         | 17 +++++++++--------
 tools/lib/bpf/libbpf.h         |  2 +-
 3 files changed, 20 insertions(+), 9 deletions(-)

Patch

diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 417cf1c31579..23ebe5e96d69 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1123,6 +1123,16 @@  enum bpf_link_type {
  */
 #define BPF_F_XDP_HAS_FRAGS	(1U << 5)
 
+/* HID flag used in BPF_LINK_CREATE command
+ *
+ * NONE(default): The bpf program will be added at the tail of the list
+ * of existing bpf program for this type.
+ *
+ * BPF_F_INSERT_HEAD: The bpf program will be added at the beginning
+ * of the list of existing bpf program for this type..
+ */
+#define BPF_F_INSERT_HEAD	(1U << 0)
+
 /* When BPF ldimm64's insn[0].src_reg != 0 then this can have
  * the following extensions:
  *
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index d1e305f760bb..6f0cb6717207 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -10533,10 +10533,11 @@  static struct bpf_link *attach_lsm(const struct bpf_program *prog, long cookie)
 
 static struct bpf_link *
 bpf_program__attach_fd(const struct bpf_program *prog, int target_fd, int btf_id,
-		       const char *target_name)
+		       const char *target_name, __u32 flags)
 {
 	DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts,
-			    .target_btf_id = btf_id);
+			    .target_btf_id = btf_id,
+			    .flags = flags);
 	enum bpf_attach_type attach_type;
 	char errmsg[STRERR_BUFSIZE];
 	struct bpf_link *link;
@@ -10570,19 +10571,19 @@  bpf_program__attach_fd(const struct bpf_program *prog, int target_fd, int btf_id
 struct bpf_link *
 bpf_program__attach_cgroup(const struct bpf_program *prog, int cgroup_fd)
 {
-	return bpf_program__attach_fd(prog, cgroup_fd, 0, "cgroup");
+	return bpf_program__attach_fd(prog, cgroup_fd, 0, "cgroup", 0);
 }
 
 struct bpf_link *
 bpf_program__attach_netns(const struct bpf_program *prog, int netns_fd)
 {
-	return bpf_program__attach_fd(prog, netns_fd, 0, "netns");
+	return bpf_program__attach_fd(prog, netns_fd, 0, "netns", 0);
 }
 
 struct bpf_link *bpf_program__attach_xdp(const struct bpf_program *prog, int ifindex)
 {
 	/* target_fd/target_ifindex use the same field in LINK_CREATE */
-	return bpf_program__attach_fd(prog, ifindex, 0, "xdp");
+	return bpf_program__attach_fd(prog, ifindex, 0, "xdp", 0);
 }
 
 struct bpf_link *bpf_program__attach_freplace(const struct bpf_program *prog,
@@ -10608,7 +10609,7 @@  struct bpf_link *bpf_program__attach_freplace(const struct bpf_program *prog,
 		if (btf_id < 0)
 			return libbpf_err_ptr(btf_id);
 
-		return bpf_program__attach_fd(prog, target_fd, btf_id, "freplace");
+		return bpf_program__attach_fd(prog, target_fd, btf_id, "freplace", 0);
 	} else {
 		/* no target, so use raw_tracepoint_open for compatibility
 		 * with old kernels
@@ -10663,9 +10664,9 @@  static struct bpf_link *attach_iter(const struct bpf_program *prog, long cookie)
 }
 
 struct bpf_link *
-bpf_program__attach_hid(const struct bpf_program *prog, int hid_fd)
+bpf_program__attach_hid(const struct bpf_program *prog, int hid_fd, __u32 flags)
 {
-	return bpf_program__attach_fd(prog, hid_fd, 0, "hid");
+	return bpf_program__attach_fd(prog, hid_fd, 0, "hid", flags);
 }
 
 struct bpf_link *bpf_program__attach(const struct bpf_program *prog)
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index f677ac0a9ede..65be3e2ec62d 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -530,7 +530,7 @@  LIBBPF_API struct bpf_link *
 bpf_program__attach_iter(const struct bpf_program *prog,
 			 const struct bpf_iter_attach_opts *opts);
 LIBBPF_API struct bpf_link *
-bpf_program__attach_hid(const struct bpf_program *prog, int hid_fd);
+bpf_program__attach_hid(const struct bpf_program *prog, int hid_fd, __u32 flags);
 
 /*
  * Libbpf allows callers to adjust BPF programs before being loaded