From 956b620fcf0b64de403cd26a56bc41e6e4826ea6 Mon Sep 17 00:00:00 2001 From: Andrey Ignatov Date: Wed, 26 Sep 2018 15:24:53 -0700 Subject: 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 Signed-off-by: Daniel Borkmann --- tools/lib/bpf/libbpf.c | 121 +++++++++++++++++++++++++++++++++---------------- tools/lib/bpf/libbpf.h | 2 + 2 files changed, 84 insertions(+), 39 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 4f8d43ae20d2..59e589a64d5c 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2085,58 +2085,82 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog, 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) +/* Programs that can be attached. */ +#define BPF_APROG_SEC(string, ptype, atype) \ + BPF_PROG_SEC_IMPL(string, ptype, 0, atype) -#define BPF_SA_PROG_SEC(string, ptype) \ - BPF_PROG_SEC_FULL(string, BPF_PROG_TYPE_CGROUP_SOCK_ADDR, ptype) +/* 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("lwt_seg6local", BPF_PROG_TYPE_LWT_SEG6LOCAL), - 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_PROG_SEC("lirc_mode2", BPF_PROG_TYPE_LIRC_MODE2), - BPF_PROG_SEC("flow_dissector", BPF_PROG_TYPE_FLOW_DISSECTOR), - 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_PROG_SEC("lwt_seg6local", BPF_PROG_TYPE_LWT_SEG6LOCAL), + 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_APROG_SEC("lirc_mode2", BPF_PROG_TYPE_LIRC_MODE2, + BPF_LIRC_MODE2), + BPF_APROG_SEC("flow_dissector", BPF_PROG_TYPE_FLOW_DISSECTOR, + BPF_FLOW_DISSECTOR), + 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) @@ -2156,6 +2180,25 @@ int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type, 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 bpf_program__identify_section(struct bpf_program *prog, enum bpf_prog_type *prog_type, diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index e3b00e23e181..511c1294dcbf 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -104,6 +104,8 @@ void *bpf_object__priv(struct bpf_object *prog); 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; -- cgit v1.2.3