[v2,net-next,1/4] libbpf: add ability to guess program type based on section name

Message ID 20171207183909.16240-2-guro@fb.com
State Changes Requested
Delegated to: BPF Maintainers
Headers show
Series
  • bpftool: cgroup bpf operations
Related show

Commit Message

Roman Gushchin Dec. 7, 2017, 6:39 p.m.
The bpf_prog_load() function will guess program type if it's not
specified explicitly. This functionality will be used to implement
loading of different programs without asking a user to specify
the program type. In first order it will be used by bpftool.

Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Quentin Monnet <quentin.monnet@netronome.com>
Cc: David Ahern <dsahern@gmail.com>
---
 tools/lib/bpf/libbpf.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

Comments

Quentin Monnet Dec. 8, 2017, 10:33 a.m. | #1
2017-12-07 18:39 UTC+0000 ~ Roman Gushchin <guro@fb.com>
> The bpf_prog_load() function will guess program type if it's not
> specified explicitly. This functionality will be used to implement
> loading of different programs without asking a user to specify
> the program type. In first order it will be used by bpftool.
> 
> Signed-off-by: Roman Gushchin <guro@fb.com>
> Cc: Alexei Starovoitov <ast@kernel.org>
> Cc: Daniel Borkmann <daniel@iogearbox.net>
> Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
> Cc: Martin KaFai Lau <kafai@fb.com>
> Cc: Quentin Monnet <quentin.monnet@netronome.com>
> Cc: David Ahern <dsahern@gmail.com>
> ---
>  tools/lib/bpf/libbpf.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 51 insertions(+)
> 
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 5aa45f89da93..205b7822fa0a 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -1721,6 +1721,45 @@ BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
>  BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
>  BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
>  
> +#define BPF_PROG_SEC(string, type) { string, sizeof(string), type }
> +static const struct {
> +	const char *sec;
> +	size_t len;
> +	enum bpf_prog_type prog_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("tracepoint/",	BPF_PROG_TYPE_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("sockops",		BPF_PROG_TYPE_SOCK_OPS),
> +	BPF_PROG_SEC("sk_skb",		BPF_PROG_TYPE_SK_SKB),
> +};
> +#undef BPF_PROG_SEC
> +
> +static enum bpf_prog_type bpf_program__guess_type(struct bpf_program *prog)
> +{
> +	int i;
> +
> +	if (!prog->section_name)
> +		goto err;
> +
> +	for (i = 0; i < ARRAY_SIZE(section_names); i++)
> +		if (strncmp(prog->section_name, section_names[i].sec,
> +			    section_names[i].len) == 0)
> +			return section_names[i].prog_type;
> +
> +err:
> +	pr_warning("failed to guess program type based on section name %s\n",
> +		   prog->section_name);
> +
> +	return BPF_PROG_TYPE_UNSPEC;
> +}
> +
>  int bpf_map__fd(struct bpf_map *map)
>  {
>  	return map ? map->fd : -EINVAL;
> @@ -1832,6 +1871,18 @@ int bpf_prog_load(const char *file, enum bpf_prog_type type,
>  		return -ENOENT;
>  	}
>  
> +	/*
> +	 * If type is not specified, try to guess it based on
> +	 * section name.
> +	 */
> +	if (type == BPF_PROG_TYPE_UNSPEC) {
> +		type = bpf_program__guess_type(prog);
> +		if (type == BPF_PROG_TYPE_UNSPEC) {
> +			bpf_object__close(obj);
> +			return -EINVAL;
> +		}
> +	}
> +
>  	bpf_program__set_type(prog, type);
>  	err = bpf_object__load(obj);
>  	if (err) {
> 

Looks good to me, nice to avoid the hard-coded string lengths :). Thanks
for the changes!

Quentin

Patch

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 5aa45f89da93..205b7822fa0a 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1721,6 +1721,45 @@  BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
 BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
 BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
 
+#define BPF_PROG_SEC(string, type) { string, sizeof(string), type }
+static const struct {
+	const char *sec;
+	size_t len;
+	enum bpf_prog_type prog_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("tracepoint/",	BPF_PROG_TYPE_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("sockops",		BPF_PROG_TYPE_SOCK_OPS),
+	BPF_PROG_SEC("sk_skb",		BPF_PROG_TYPE_SK_SKB),
+};
+#undef BPF_PROG_SEC
+
+static enum bpf_prog_type bpf_program__guess_type(struct bpf_program *prog)
+{
+	int i;
+
+	if (!prog->section_name)
+		goto err;
+
+	for (i = 0; i < ARRAY_SIZE(section_names); i++)
+		if (strncmp(prog->section_name, section_names[i].sec,
+			    section_names[i].len) == 0)
+			return section_names[i].prog_type;
+
+err:
+	pr_warning("failed to guess program type based on section name %s\n",
+		   prog->section_name);
+
+	return BPF_PROG_TYPE_UNSPEC;
+}
+
 int bpf_map__fd(struct bpf_map *map)
 {
 	return map ? map->fd : -EINVAL;
@@ -1832,6 +1871,18 @@  int bpf_prog_load(const char *file, enum bpf_prog_type type,
 		return -ENOENT;
 	}
 
+	/*
+	 * If type is not specified, try to guess it based on
+	 * section name.
+	 */
+	if (type == BPF_PROG_TYPE_UNSPEC) {
+		type = bpf_program__guess_type(prog);
+		if (type == BPF_PROG_TYPE_UNSPEC) {
+			bpf_object__close(obj);
+			return -EINVAL;
+		}
+	}
+
 	bpf_program__set_type(prog, type);
 	err = bpf_object__load(obj);
 	if (err) {