From: Andrey Ignatov <rdna@fb.com>
Date: Wed, 26 Sep 2018 15:24:53 -0700
Subject: libbpf: Introduce libbpf_attach_type_by_name
Patch-mainline: v4.20-rc1
Git-commit: 956b620fcf0b64de403cd26a56bc41e6e4826ea6
References: bsc#1109837
There is a common use-case when ELF object contains multiple BPF
programs and every program has its own section name. If it's cgroup-bpf
then programs have to be 1) loaded and 2) attached to a cgroup.
It's convenient to have information necessary to load BPF program
together with program itself. This is where section name works fine in
conjunction with libbpf_prog_type_by_name that identifies prog_type and
expected_attach_type and these can be used with BPF_PROG_LOAD.
But there is currently no way to identify attach_type by section name
and it leads to messy code in user space that reinvents guessing logic
every time it has to identify attach type to use with BPF_PROG_ATTACH.
The patch introduces libbpf_attach_type_by_name that guesses attach type
by section name if a program can be attached.
The difference between expected_attach_type provided by
libbpf_prog_type_by_name and attach_type provided by
libbpf_attach_type_by_name is the former is used at BPF_PROG_LOAD time
and can be zero if a program of prog_type X has only one corresponding
attach type Y whether the latter provides specific attach type to use
with BPF_PROG_ATTACH.
No new section names were added to section_names array. Only existing
ones were reorganized and attach_type was added where appropriate.
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
tools/lib/bpf/libbpf.c | 115 +++++++++++++++++++++++++++++++++----------------
tools/lib/bpf/libbpf.h | 2
2 files changed, 80 insertions(+), 37 deletions(-)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2081,55 +2081,77 @@ void bpf_program__set_expected_attach_ty
prog->expected_attach_type = type;
}
-#define BPF_PROG_SEC_FULL(string, ptype, atype) \
- { string, sizeof(string) - 1, ptype, atype }
+#define BPF_PROG_SEC_IMPL(string, ptype, eatype, atype) \
+ { string, sizeof(string) - 1, ptype, eatype, atype }
-#define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_FULL(string, ptype, 0)
+/* Programs that can NOT be attached. */
+#define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, -EINVAL)
-#define BPF_S_PROG_SEC(string, ptype) \
- BPF_PROG_SEC_FULL(string, BPF_PROG_TYPE_CGROUP_SOCK, ptype)
-
-#define BPF_SA_PROG_SEC(string, ptype) \
- BPF_PROG_SEC_FULL(string, BPF_PROG_TYPE_CGROUP_SOCK_ADDR, ptype)
+/* Programs that can be attached. */
+#define BPF_APROG_SEC(string, ptype, atype) \
+ BPF_PROG_SEC_IMPL(string, ptype, 0, atype)
+
+/* Programs that must specify expected attach type at load time. */
+#define BPF_EAPROG_SEC(string, ptype, eatype) \
+ BPF_PROG_SEC_IMPL(string, ptype, eatype, eatype)
+
+/* Programs that can be attached but attach type can't be identified by section
+ * name. Kept for backward compatibility.
+ */
+#define BPF_APROG_COMPAT(string, ptype) BPF_PROG_SEC(string, ptype)
static const struct {
const char *sec;
size_t len;
enum bpf_prog_type prog_type;
enum bpf_attach_type expected_attach_type;
+ enum bpf_attach_type attach_type;
} section_names[] = {
- BPF_PROG_SEC("socket", BPF_PROG_TYPE_SOCKET_FILTER),
- BPF_PROG_SEC("kprobe/", BPF_PROG_TYPE_KPROBE),
- BPF_PROG_SEC("kretprobe/", BPF_PROG_TYPE_KPROBE),
- BPF_PROG_SEC("classifier", BPF_PROG_TYPE_SCHED_CLS),
- BPF_PROG_SEC("action", BPF_PROG_TYPE_SCHED_ACT),
- BPF_PROG_SEC("tracepoint/", BPF_PROG_TYPE_TRACEPOINT),
- BPF_PROG_SEC("raw_tracepoint/", BPF_PROG_TYPE_RAW_TRACEPOINT),
- BPF_PROG_SEC("xdp", BPF_PROG_TYPE_XDP),
- BPF_PROG_SEC("perf_event", BPF_PROG_TYPE_PERF_EVENT),
- BPF_PROG_SEC("cgroup/skb", BPF_PROG_TYPE_CGROUP_SKB),
- BPF_PROG_SEC("cgroup/sock", BPF_PROG_TYPE_CGROUP_SOCK),
- BPF_PROG_SEC("cgroup/dev", BPF_PROG_TYPE_CGROUP_DEVICE),
- BPF_PROG_SEC("lwt_in", BPF_PROG_TYPE_LWT_IN),
- BPF_PROG_SEC("lwt_out", BPF_PROG_TYPE_LWT_OUT),
- BPF_PROG_SEC("lwt_xmit", BPF_PROG_TYPE_LWT_XMIT),
- BPF_PROG_SEC("sockops", BPF_PROG_TYPE_SOCK_OPS),
- BPF_PROG_SEC("sk_skb", BPF_PROG_TYPE_SK_SKB),
- BPF_PROG_SEC("sk_msg", BPF_PROG_TYPE_SK_MSG),
- BPF_SA_PROG_SEC("cgroup/bind4", BPF_CGROUP_INET4_BIND),
- BPF_SA_PROG_SEC("cgroup/bind6", BPF_CGROUP_INET6_BIND),
- BPF_SA_PROG_SEC("cgroup/connect4", BPF_CGROUP_INET4_CONNECT),
- BPF_SA_PROG_SEC("cgroup/connect6", BPF_CGROUP_INET6_CONNECT),
- BPF_SA_PROG_SEC("cgroup/sendmsg4", BPF_CGROUP_UDP4_SENDMSG),
- BPF_SA_PROG_SEC("cgroup/sendmsg6", BPF_CGROUP_UDP6_SENDMSG),
- BPF_S_PROG_SEC("cgroup/post_bind4", BPF_CGROUP_INET4_POST_BIND),
- BPF_S_PROG_SEC("cgroup/post_bind6", BPF_CGROUP_INET6_POST_BIND),
+ BPF_PROG_SEC("socket", BPF_PROG_TYPE_SOCKET_FILTER),
+ BPF_PROG_SEC("kprobe/", BPF_PROG_TYPE_KPROBE),
+ BPF_PROG_SEC("kretprobe/", BPF_PROG_TYPE_KPROBE),
+ BPF_PROG_SEC("classifier", BPF_PROG_TYPE_SCHED_CLS),
+ BPF_PROG_SEC("action", BPF_PROG_TYPE_SCHED_ACT),
+ BPF_PROG_SEC("tracepoint/", BPF_PROG_TYPE_TRACEPOINT),
+ BPF_PROG_SEC("raw_tracepoint/", BPF_PROG_TYPE_RAW_TRACEPOINT),
+ BPF_PROG_SEC("xdp", BPF_PROG_TYPE_XDP),
+ BPF_PROG_SEC("perf_event", BPF_PROG_TYPE_PERF_EVENT),
+ BPF_PROG_SEC("lwt_in", BPF_PROG_TYPE_LWT_IN),
+ BPF_PROG_SEC("lwt_out", BPF_PROG_TYPE_LWT_OUT),
+ BPF_PROG_SEC("lwt_xmit", BPF_PROG_TYPE_LWT_XMIT),
+ BPF_APROG_COMPAT("cgroup/skb", BPF_PROG_TYPE_CGROUP_SKB),
+ BPF_APROG_SEC("cgroup/sock", BPF_PROG_TYPE_CGROUP_SOCK,
+ BPF_CGROUP_INET_SOCK_CREATE),
+ BPF_EAPROG_SEC("cgroup/post_bind4", BPF_PROG_TYPE_CGROUP_SOCK,
+ BPF_CGROUP_INET4_POST_BIND),
+ BPF_EAPROG_SEC("cgroup/post_bind6", BPF_PROG_TYPE_CGROUP_SOCK,
+ BPF_CGROUP_INET6_POST_BIND),
+ BPF_APROG_SEC("cgroup/dev", BPF_PROG_TYPE_CGROUP_DEVICE,
+ BPF_CGROUP_DEVICE),
+ BPF_APROG_SEC("sockops", BPF_PROG_TYPE_SOCK_OPS,
+ BPF_CGROUP_SOCK_OPS),
+ BPF_APROG_COMPAT("sk_skb", BPF_PROG_TYPE_SK_SKB),
+ BPF_APROG_SEC("sk_msg", BPF_PROG_TYPE_SK_MSG,
+ BPF_SK_MSG_VERDICT),
+ BPF_EAPROG_SEC("cgroup/bind4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
+ BPF_CGROUP_INET4_BIND),
+ BPF_EAPROG_SEC("cgroup/bind6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
+ BPF_CGROUP_INET6_BIND),
+ BPF_EAPROG_SEC("cgroup/connect4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
+ BPF_CGROUP_INET4_CONNECT),
+ BPF_EAPROG_SEC("cgroup/connect6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
+ BPF_CGROUP_INET6_CONNECT),
+ BPF_EAPROG_SEC("cgroup/sendmsg4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
+ BPF_CGROUP_UDP4_SENDMSG),
+ BPF_EAPROG_SEC("cgroup/sendmsg6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
+ BPF_CGROUP_UDP6_SENDMSG),
};
+#undef BPF_PROG_SEC_IMPL
#undef BPF_PROG_SEC
-#undef BPF_PROG_SEC_FULL
-#undef BPF_S_PROG_SEC
-#undef BPF_SA_PROG_SEC
+#undef BPF_APROG_SEC
+#undef BPF_EAPROG_SEC
+#undef BPF_APROG_COMPAT
int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
enum bpf_attach_type *expected_attach_type)
@@ -2147,6 +2169,25 @@ int libbpf_prog_type_by_name(const char
return 0;
}
return -EINVAL;
+}
+
+int libbpf_attach_type_by_name(const char *name,
+ enum bpf_attach_type *attach_type)
+{
+ int i;
+
+ if (!name)
+ return -EINVAL;
+
+ for (i = 0; i < ARRAY_SIZE(section_names); i++) {
+ if (strncmp(name, section_names[i].sec, section_names[i].len))
+ continue;
+ if (section_names[i].attach_type == -EINVAL)
+ return -EINVAL;
+ *attach_type = section_names[i].attach_type;
+ return 0;
+ }
+ return -EINVAL;
}
static int
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -104,6 +104,8 @@ void *bpf_object__priv(struct bpf_object
int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
enum bpf_attach_type *expected_attach_type);
+int libbpf_attach_type_by_name(const char *name,
+ enum bpf_attach_type *attach_type);
/* Accessors of bpf_program */
struct bpf_program;