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Message-Id: <20181217102501.22019-6-bjorn.topel@gmail.com>
Date: Mon, 17 Dec 2018 11:24:59 +0100
From: Björn Töpel <bjorn.topel@...il.com>
To: bjorn.topel@...il.com, magnus.karlsson@...el.com,
magnus.karlsson@...il.com, ast@...nel.org, daniel@...earbox.net,
netdev@...r.kernel.org
Cc: Björn Töpel <bjorn.topel@...el.com>,
brouer@...hat.com, u9012063@...il.com, qi.z.zhang@...el.com,
jakub.kicinski@...ronome.com, andrew@...n.ch
Subject: [PATCH bpf-next v2 5/7] libbpf: initial support for builtin BPF programs
From: Björn Töpel <bjorn.topel@...el.com>
This commit introduces builtin BPF programs to libbpf. A builtin
program is simply a BPF program that is bundled with libbpf.
The first builtin program is an XDP program, "xdp_xsk_redirect", which
is a trivial program that calls bpf_xsk_redirect for each received
packet, and redirects it to the corresponding XDP socket.
Two new functions are added to the libbpf API:
LIBBPF_API struct bpf_object *bpf_object__open_builtin(
enum bpf_prog_type prog_type);
LIBBPF_API struct bpf_program *
bpf_object__find_xdp_builtin_program(
struct bpf_object* obj,
enum libbpf_builtin_xdp_prog prog);
The first function is used to get a handle to the bpf_object
containing all builtin programs for a certain program type. The latter
is used to access a certain builtin program from the bpf_object. Note
that currenty only XDP is supported. When other program types are
supported, additional bpf_object__find_PROG_TYPE_builtin_program
function are required.
When/if packet cloning is introduced to XDP, another builtin program
candidate would be a program that clones all packets to an XDP socket.
Signed-off-by: Björn Töpel <bjorn.topel@...el.com>
---
tools/lib/bpf/libbpf.c | 85 ++++++++++++++++++++++++++++++++++++++++
tools/lib/bpf/libbpf.h | 14 +++++++
tools/lib/bpf/libbpf.map | 2 +
3 files changed, 101 insertions(+)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index e2bc75ee1614..d8551193862b 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -242,6 +242,31 @@ struct bpf_object {
};
#define obj_elf_valid(o) ((o)->efile.elf)
+struct libbpf_builtin_prog {
+ const char *name;
+ const struct bpf_insn *insns;
+ size_t size;
+};
+
+/*
+ * Builtin XDP program: LIBBPF_BUILTIN_XDP__XSK_REDIRECT
+ *
+ * Trivial XDP program that calls bpf_xsk_redirect() on every received
+ * frame.
+ */
+static const struct bpf_insn builtin_xdp_xsk_redirect_insn[] = {
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_xsk_redirect),
+ BPF_EXIT_INSN(),
+};
+
+static const struct libbpf_builtin_prog libbpf_builtin_xdp_prog[] = {
+ [LIBBPF_BUILTIN_XDP__XSK_REDIRECT] = {
+ "xdp_xsk_redirect",
+ &builtin_xdp_xsk_redirect_insn[0],
+ sizeof(builtin_xdp_xsk_redirect_insn)
+ },
+};
+
void bpf_program__unload(struct bpf_program *prog)
{
int i;
@@ -2990,3 +3015,63 @@ bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
ring_buffer_write_tail(header, data_tail);
return ret;
}
+
+struct bpf_object *bpf_object__open_builtin(enum bpf_prog_type prog_type)
+{
+ struct bpf_program *prog;
+ struct bpf_object *obj;
+ int err, i;
+
+ /* Right now, only XDP is supported. */
+ if (prog_type != BPF_PROG_TYPE_XDP)
+ return ERR_PTR(-EINVAL);
+
+ obj = bpf_object__new("", NULL, 0);
+ if (IS_ERR(obj))
+ return NULL;
+
+ CHECK_ERR(bpf_object__init_license(obj, (void *)"GPL", sizeof("GPL")),
+ err, out);
+
+ for (i = 0; i < __LIBBPF_BUILTIN_XDP__END; i++) {
+ err = bpf_object__add_program(
+ obj,
+ (void *)libbpf_builtin_xdp_prog[i].insns,
+ libbpf_builtin_xdp_prog[i].size,
+ (char *)libbpf_builtin_xdp_prog[i].name, i);
+ if (err) {
+ pr_warning("failed to add builtin program %s\n",
+ libbpf_builtin_xdp_prog[i].name);
+ goto out;
+ }
+ }
+
+ bpf_object__for_each_program(prog, obj) {
+ bpf_program__set_type(prog, BPF_PROG_TYPE_XDP);
+
+ prog->name = strdup(libbpf_builtin_xdp_prog[prog->idx].name);
+ if (!prog->name) {
+ pr_warning("failed to allocate memory for name %s\n",
+ libbpf_builtin_xdp_prog[prog->idx].name);
+ goto out;
+ }
+ }
+
+ return obj;
+out:
+ bpf_object__close(obj);
+ return NULL;
+
+}
+
+struct bpf_program *bpf_object__find_xdp_builtin_program(
+ struct bpf_object *obj, enum libbpf_builtin_xdp_prog prog)
+{
+ if (!obj)
+ return NULL;
+
+ if (prog < 0 || prog >= __LIBBPF_BUILTIN_XDP__END)
+ return NULL;
+
+ return bpf_object__find_prog_by_idx(obj, prog);
+}
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 5f68d7b75215..0de0cc2da240 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -45,6 +45,15 @@ enum libbpf_errno {
__LIBBPF_ERRNO__END,
};
+enum libbpf_builtin_xdp_prog {
+ /*
+ * Trivial XDP program that calls bpf_xsk_redirect
+ * unconditionally for every received packet.
+ */
+ LIBBPF_BUILTIN_XDP__XSK_REDIRECT,
+ __LIBBPF_BUILTIN_XDP__END,
+};
+
LIBBPF_API int libbpf_strerror(int err, char *buf, size_t size);
/*
@@ -75,6 +84,8 @@ struct bpf_object *__bpf_object__open_xattr(struct bpf_object_open_attr *attr,
LIBBPF_API struct bpf_object *bpf_object__open_buffer(void *obj_buf,
size_t obj_buf_sz,
const char *name);
+LIBBPF_API struct bpf_object *bpf_object__open_builtin(
+ enum bpf_prog_type prog_type);
LIBBPF_API int bpf_object__pin_maps(struct bpf_object *obj, const char *path);
LIBBPF_API int bpf_object__unpin_maps(struct bpf_object *obj,
const char *path);
@@ -94,6 +105,9 @@ LIBBPF_API int bpf_object__btf_fd(const struct bpf_object *obj);
LIBBPF_API struct bpf_program *
bpf_object__find_program_by_title(struct bpf_object *obj, const char *title);
+LIBBPF_API struct bpf_program *
+bpf_object__find_xdp_builtin_program(struct bpf_object *obj,
+ enum libbpf_builtin_xdp_prog prog);
LIBBPF_API struct bpf_object *bpf_object__next(struct bpf_object *prev);
#define bpf_object__for_each_safe(pos, tmp) \
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index cd02cd4e2cc3..58acd84d5ff3 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -121,6 +121,8 @@ LIBBPF_0.0.1 {
libbpf_prog_type_by_name;
libbpf_set_print;
libbpf_strerror;
+ bpf_object__open_builtin;
+ bpf_object__find_xdp_builtin_program;
local:
*;
};
--
2.19.1
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