libbpf: Introduce libbpf_attach_type_by_name
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>
This commit is contained in:
Andrey Ignatov
Daniel Borkmann
Родитель
100811936f
Коммит
956b620fcf
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@ -2085,22 +2085,31 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog,
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prog->expected_attach_type = type;
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}
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#define BPF_PROG_SEC_FULL(string, ptype, atype) \
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{ string, sizeof(string) - 1, ptype, atype }
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#define BPF_PROG_SEC_IMPL(string, ptype, eatype, atype) \
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{ string, sizeof(string) - 1, ptype, eatype, atype }
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#define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_FULL(string, ptype, 0)
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/* Programs that can NOT be attached. */
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#define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, -EINVAL)
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#define BPF_S_PROG_SEC(string, ptype) \
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BPF_PROG_SEC_FULL(string, BPF_PROG_TYPE_CGROUP_SOCK, ptype)
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/* Programs that can be attached. */
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#define BPF_APROG_SEC(string, ptype, atype) \
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BPF_PROG_SEC_IMPL(string, ptype, 0, atype)
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#define BPF_SA_PROG_SEC(string, ptype) \
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BPF_PROG_SEC_FULL(string, BPF_PROG_TYPE_CGROUP_SOCK_ADDR, ptype)
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/* Programs that must specify expected attach type at load time. */
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#define BPF_EAPROG_SEC(string, ptype, eatype) \
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BPF_PROG_SEC_IMPL(string, ptype, eatype, eatype)
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/* Programs that can be attached but attach type can't be identified by section
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* name. Kept for backward compatibility.
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*/
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#define BPF_APROG_COMPAT(string, ptype) BPF_PROG_SEC(string, ptype)
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static const struct {
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const char *sec;
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size_t len;
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enum bpf_prog_type prog_type;
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enum bpf_attach_type expected_attach_type;
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enum bpf_attach_type attach_type;
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} section_names[] = {
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BPF_PROG_SEC("socket", BPF_PROG_TYPE_SOCKET_FILTER),
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BPF_PROG_SEC("kprobe/", BPF_PROG_TYPE_KPROBE),
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@ -2111,32 +2120,47 @@ static const struct {
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BPF_PROG_SEC("raw_tracepoint/", BPF_PROG_TYPE_RAW_TRACEPOINT),
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BPF_PROG_SEC("xdp", BPF_PROG_TYPE_XDP),
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BPF_PROG_SEC("perf_event", BPF_PROG_TYPE_PERF_EVENT),
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BPF_PROG_SEC("cgroup/skb", BPF_PROG_TYPE_CGROUP_SKB),
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BPF_PROG_SEC("cgroup/sock", BPF_PROG_TYPE_CGROUP_SOCK),
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BPF_PROG_SEC("cgroup/dev", BPF_PROG_TYPE_CGROUP_DEVICE),
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BPF_PROG_SEC("lwt_in", BPF_PROG_TYPE_LWT_IN),
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BPF_PROG_SEC("lwt_out", BPF_PROG_TYPE_LWT_OUT),
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BPF_PROG_SEC("lwt_xmit", BPF_PROG_TYPE_LWT_XMIT),
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BPF_PROG_SEC("lwt_seg6local", BPF_PROG_TYPE_LWT_SEG6LOCAL),
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BPF_PROG_SEC("sockops", BPF_PROG_TYPE_SOCK_OPS),
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BPF_PROG_SEC("sk_skb", BPF_PROG_TYPE_SK_SKB),
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BPF_PROG_SEC("sk_msg", BPF_PROG_TYPE_SK_MSG),
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BPF_PROG_SEC("lirc_mode2", BPF_PROG_TYPE_LIRC_MODE2),
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BPF_PROG_SEC("flow_dissector", BPF_PROG_TYPE_FLOW_DISSECTOR),
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BPF_SA_PROG_SEC("cgroup/bind4", BPF_CGROUP_INET4_BIND),
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BPF_SA_PROG_SEC("cgroup/bind6", BPF_CGROUP_INET6_BIND),
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BPF_SA_PROG_SEC("cgroup/connect4", BPF_CGROUP_INET4_CONNECT),
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BPF_SA_PROG_SEC("cgroup/connect6", BPF_CGROUP_INET6_CONNECT),
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BPF_SA_PROG_SEC("cgroup/sendmsg4", BPF_CGROUP_UDP4_SENDMSG),
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BPF_SA_PROG_SEC("cgroup/sendmsg6", BPF_CGROUP_UDP6_SENDMSG),
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BPF_S_PROG_SEC("cgroup/post_bind4", BPF_CGROUP_INET4_POST_BIND),
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BPF_S_PROG_SEC("cgroup/post_bind6", BPF_CGROUP_INET6_POST_BIND),
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BPF_APROG_COMPAT("cgroup/skb", BPF_PROG_TYPE_CGROUP_SKB),
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BPF_APROG_SEC("cgroup/sock", BPF_PROG_TYPE_CGROUP_SOCK,
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BPF_CGROUP_INET_SOCK_CREATE),
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BPF_EAPROG_SEC("cgroup/post_bind4", BPF_PROG_TYPE_CGROUP_SOCK,
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BPF_CGROUP_INET4_POST_BIND),
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BPF_EAPROG_SEC("cgroup/post_bind6", BPF_PROG_TYPE_CGROUP_SOCK,
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BPF_CGROUP_INET6_POST_BIND),
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BPF_APROG_SEC("cgroup/dev", BPF_PROG_TYPE_CGROUP_DEVICE,
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BPF_CGROUP_DEVICE),
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BPF_APROG_SEC("sockops", BPF_PROG_TYPE_SOCK_OPS,
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BPF_CGROUP_SOCK_OPS),
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BPF_APROG_COMPAT("sk_skb", BPF_PROG_TYPE_SK_SKB),
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BPF_APROG_SEC("sk_msg", BPF_PROG_TYPE_SK_MSG,
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BPF_SK_MSG_VERDICT),
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BPF_APROG_SEC("lirc_mode2", BPF_PROG_TYPE_LIRC_MODE2,
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BPF_LIRC_MODE2),
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BPF_APROG_SEC("flow_dissector", BPF_PROG_TYPE_FLOW_DISSECTOR,
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BPF_FLOW_DISSECTOR),
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BPF_EAPROG_SEC("cgroup/bind4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
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BPF_CGROUP_INET4_BIND),
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BPF_EAPROG_SEC("cgroup/bind6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
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BPF_CGROUP_INET6_BIND),
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BPF_EAPROG_SEC("cgroup/connect4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
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BPF_CGROUP_INET4_CONNECT),
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BPF_EAPROG_SEC("cgroup/connect6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
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BPF_CGROUP_INET6_CONNECT),
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BPF_EAPROG_SEC("cgroup/sendmsg4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
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BPF_CGROUP_UDP4_SENDMSG),
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BPF_EAPROG_SEC("cgroup/sendmsg6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
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BPF_CGROUP_UDP6_SENDMSG),
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};
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#undef BPF_PROG_SEC_IMPL
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#undef BPF_PROG_SEC
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#undef BPF_PROG_SEC_FULL
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#undef BPF_S_PROG_SEC
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#undef BPF_SA_PROG_SEC
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#undef BPF_APROG_SEC
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#undef BPF_EAPROG_SEC
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#undef BPF_APROG_COMPAT
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int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
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enum bpf_attach_type *expected_attach_type)
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@ -2156,6 +2180,25 @@ int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
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return -EINVAL;
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}
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int libbpf_attach_type_by_name(const char *name,
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enum bpf_attach_type *attach_type)
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{
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int i;
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if (!name)
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return -EINVAL;
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for (i = 0; i < ARRAY_SIZE(section_names); i++) {
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if (strncmp(name, section_names[i].sec, section_names[i].len))
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continue;
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if (section_names[i].attach_type == -EINVAL)
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return -EINVAL;
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*attach_type = section_names[i].attach_type;
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return 0;
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}
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return -EINVAL;
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}
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static int
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bpf_program__identify_section(struct bpf_program *prog,
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enum bpf_prog_type *prog_type,
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@ -104,6 +104,8 @@ void *bpf_object__priv(struct bpf_object *prog);
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int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
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enum bpf_attach_type *expected_attach_type);
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int libbpf_attach_type_by_name(const char *name,
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enum bpf_attach_type *attach_type);
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/* Accessors of bpf_program */
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struct bpf_program;
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