libbpf: add support for scheduler bpf programs

maillist inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5F6X6
CVE: NA

Reference: https://lore.kernel.org/all/20210916162451.709260-1-guro@fb.com/

-------------------

This patch adds a support for loading and attaching scheduler bpf
programs.
Signed-off-by: NRoman Gushchin <guro@fb.com>
Signed-off-by: NChen Hui <judy.chenhui@huawei.com>
Signed-off-by: NRen Zhijie <renzhijie2@huawei.com>
Signed-off-by: NHui Tang <tanghui20@huawei.com>

tools/lib/bpf/libbpf.c

@@ -2504,7 +2504,8 @@ static int bpf_object__finalize_btf(struct bpf_object *obj)
 static inline bool libbpf_prog_needs_vmlinux_btf(struct bpf_program *prog)
 {
 	if (prog->type == BPF_PROG_TYPE_STRUCT_OPS ||
-	    prog->type == BPF_PROG_TYPE_LSM)
+	    prog->type == BPF_PROG_TYPE_LSM ||
+	    prog->type == BPF_PROG_TYPE_SCHED)
 		return true;
 
 	/* BPF_PROG_TYPE_TRACING programs which do not attach to other programs
@@ -6829,7 +6830,8 @@ int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver)
 
 	if ((prog->type == BPF_PROG_TYPE_TRACING ||
 	     prog->type == BPF_PROG_TYPE_LSM ||
-	     prog->type == BPF_PROG_TYPE_EXT) && !prog->attach_btf_id) {
+	     prog->type == BPF_PROG_TYPE_EXT ||
+	     prog->type == BPF_PROG_TYPE_SCHED) && !prog->attach_btf_id) {
 		btf_id = libbpf_find_attach_btf_id(prog);
 		if (btf_id <= 0)
 			return btf_id;
@@ -8254,6 +8256,7 @@ BPF_PROG_TYPE_FNS(tracing, BPF_PROG_TYPE_TRACING);
 BPF_PROG_TYPE_FNS(struct_ops, BPF_PROG_TYPE_STRUCT_OPS);
 BPF_PROG_TYPE_FNS(extension, BPF_PROG_TYPE_EXT);
 BPF_PROG_TYPE_FNS(sk_lookup, BPF_PROG_TYPE_SK_LOOKUP);
+BPF_PROG_TYPE_FNS(sched, BPF_PROG_TYPE_SCHED);
 
 enum bpf_attach_type
 bpf_program__get_expected_attach_type(struct bpf_program *prog)
@@ -8318,6 +8321,8 @@ static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec,
 				   struct bpf_program *prog);
 static struct bpf_link *attach_iter(const struct bpf_sec_def *sec,
 				    struct bpf_program *prog);
+static struct bpf_link *attach_sched(const struct bpf_sec_def *sec,
+				    struct bpf_program *prog);
 
 static const struct bpf_sec_def section_defs[] = {
 	BPF_PROG_SEC("socket",			BPF_PROG_TYPE_SOCKET_FILTER),
@@ -8386,6 +8391,10 @@ static const struct bpf_sec_def section_defs[] = {
 		.expected_attach_type = BPF_TRACE_ITER,
 		.is_attach_btf = true,
 		.attach_fn = attach_iter),
+	SEC_DEF("sched/", SCHED,
+		.is_attach_btf = true,
+		.expected_attach_type = BPF_SCHED,
+		.attach_fn = attach_sched),
 	BPF_EAPROG_SEC("xdp_devmap/",		BPF_PROG_TYPE_XDP,
 						BPF_XDP_DEVMAP),
 	BPF_EAPROG_SEC("xdp_cpumap/",		BPF_PROG_TYPE_XDP,
@@ -8469,7 +8478,7 @@ static const struct bpf_sec_def section_defs[] = {
 #undef BPF_APROG_COMPAT
 #undef SEC_DEF
 
-#define MAX_TYPE_NAME_SIZE 32
+#define MAX_TYPE_NAME_SIZE 31
 
 static const struct bpf_sec_def *find_sec_def(const char *sec_name)
 {
@@ -8673,6 +8682,7 @@ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj,
 #define BTF_TRACE_PREFIX "btf_trace_"
 #define BTF_LSM_PREFIX "bpf_lsm_"
 #define BTF_ITER_PREFIX "bpf_iter_"
+#define BTF_SCHED_PREFIX "bpf_sched_"
 #define BTF_MAX_NAME_SIZE 128
 
 static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix,
@@ -8706,6 +8716,9 @@ static inline int __find_vmlinux_btf_id(struct btf *btf, const char *name,
 	else if (attach_type == BPF_TRACE_ITER)
 		err = find_btf_by_prefix_kind(btf, BTF_ITER_PREFIX, name,
 					      BTF_KIND_FUNC);
+	else if (attach_type == BPF_SCHED)
+		err = find_btf_by_prefix_kind(btf, BTF_SCHED_PREFIX, name,
+					      BTF_KIND_FUNC);
 	else
 		err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC);
 
@@ -9685,6 +9698,11 @@ struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog)
 	return bpf_program__attach_btf_id(prog);
 }
 
+struct bpf_link *bpf_program__attach_sched(struct bpf_program *prog)
+{
+	return bpf_program__attach_btf_id(prog);
+}
+
 struct bpf_link *bpf_program__attach_lsm(struct bpf_program *prog)
 {
 	return bpf_program__attach_btf_id(prog);
@@ -9696,6 +9714,12 @@ static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,
 	return bpf_program__attach_trace(prog);
 }
 
+static struct bpf_link *attach_sched(const struct bpf_sec_def *sec,
+				     struct bpf_program *prog)
+{
+	return bpf_program__attach_sched(prog);
+}
+
 static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec,
 				   struct bpf_program *prog)
 {

tools/lib/bpf/libbpf.h

@@ -264,6 +264,8 @@ bpf_program__attach_xdp(struct bpf_program *prog, int ifindex);
 LIBBPF_API struct bpf_link *
 bpf_program__attach_freplace(struct bpf_program *prog,
 			     int target_fd, const char *attach_func_name);
+LIBBPF_API struct bpf_link *
+bpf_program__attach_sched(struct bpf_program *prog);
 
 struct bpf_map;
 
@@ -360,6 +362,7 @@ LIBBPF_API int bpf_program__set_tracing(struct bpf_program *prog);
 LIBBPF_API int bpf_program__set_struct_ops(struct bpf_program *prog);
 LIBBPF_API int bpf_program__set_extension(struct bpf_program *prog);
 LIBBPF_API int bpf_program__set_sk_lookup(struct bpf_program *prog);
+LIBBPF_API int bpf_program__set_sched(struct bpf_program *prog);
 
 LIBBPF_API enum bpf_prog_type bpf_program__get_type(struct bpf_program *prog);
 LIBBPF_API void bpf_program__set_type(struct bpf_program *prog,
@@ -388,6 +391,7 @@ LIBBPF_API bool bpf_program__is_tracing(const struct bpf_program *prog);
 LIBBPF_API bool bpf_program__is_struct_ops(const struct bpf_program *prog);
 LIBBPF_API bool bpf_program__is_extension(const struct bpf_program *prog);
 LIBBPF_API bool bpf_program__is_sk_lookup(const struct bpf_program *prog);
+LIBBPF_API bool bpf_program__is_sched(const struct bpf_program *prog);
 
 /*
  * No need for __attribute__((packed)), all members of 'bpf_map_def'

tools/lib/bpf/libbpf.map

@@ -336,4 +336,7 @@ LIBBPF_0.2.0 {
 		perf_buffer__epoll_fd;
 		perf_buffer__consume_buffer;
 		xsk_socket__create_shared;
+		bpf_program__attach_sched;
+		bpf_program__is_sched;
+		bpf_program__set_sched;
 } LIBBPF_0.1.0;