From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexei Starovoitov Subject: [PATCH RFC v2 net-next 14/16] samples: bpf: add mini eBPF library to manipulate maps and programs Date: Thu, 17 Jul 2014 21:20:04 -0700 Message-ID: <1405657206-12060-15-git-send-email-ast@plumgrid.com> References: <1405657206-12060-1-git-send-email-ast@plumgrid.com> Return-path: In-Reply-To: <1405657206-12060-1-git-send-email-ast@plumgrid.com> Sender: linux-kernel-owner@vger.kernel.org To: "David S. Miller" Cc: Ingo Molnar , Linus Torvalds , Andy Lutomirski , Steven Rostedt , Daniel Borkmann , Chema Gonzalez , Eric Dumazet , Peter Zijlstra , Arnaldo Carvalho de Melo , Jiri Olsa , Thomas Gleixner , "H. Peter Anvin" , Andrew Morton , Kees Cook , linux-api@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-api@vger.kernel.org the library includes a trivial set of BPF syscall wrappers: int bpf_create_map(int key_size, int value_size, int max_entries); int bpf_update_elem(int fd, void *key, void *value); int bpf_lookup_elem(int fd, void *key, void *value); int bpf_delete_elem(int fd, void *key); int bpf_get_next_key(int fd, void *key, void *next_key); int bpf_prog_load(enum bpf_prog_type prog_type, const struct sock_filter_int *insns, int insn_len, const char *license, const struct bpf_map_fixup *fixups, int fixup_len); Signed-off-by: Alexei Starovoitov --- samples/bpf/libbpf.c | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++ samples/bpf/libbpf.h | 22 ++++++++++ 2 files changed, 131 insertions(+) create mode 100644 samples/bpf/libbpf.c create mode 100644 samples/bpf/libbpf.h diff --git a/samples/bpf/libbpf.c b/samples/bpf/libbpf.c new file mode 100644 index 000000000000..5460d1f3ad43 --- /dev/null +++ b/samples/bpf/libbpf.c @@ -0,0 +1,109 @@ +/* eBPF mini library */ +#include +#include +#include +#include +#include +#include +#include +#include "libbpf.h" + +struct nlattr_u32 { + __u16 nla_len; + __u16 nla_type; + __u32 val; +}; + +int bpf_create_map(int key_size, int value_size, int max_entries) +{ + struct nlattr_u32 attr[] = { + { + .nla_len = sizeof(struct nlattr_u32), + .nla_type = BPF_MAP_KEY_SIZE, + .val = key_size, + }, + { + .nla_len = sizeof(struct nlattr_u32), + .nla_type = BPF_MAP_VALUE_SIZE, + .val = value_size, + }, + { + .nla_len = sizeof(struct nlattr_u32), + .nla_type = BPF_MAP_MAX_ENTRIES, + .val = max_entries, + }, + }; + + return syscall(__NR_bpf, BPF_MAP_CREATE, BPF_MAP_TYPE_HASH, attr, sizeof(attr)); +} + + +int bpf_update_elem(int fd, void *key, void *value) +{ + return syscall(__NR_bpf, BPF_MAP_UPDATE_ELEM, fd, key, value); +} + +int bpf_lookup_elem(int fd, void *key, void *value) +{ + return syscall(__NR_bpf, BPF_MAP_LOOKUP_ELEM, fd, key, value); +} + +int bpf_delete_elem(int fd, void *key) +{ + return syscall(__NR_bpf, BPF_MAP_DELETE_ELEM, fd, key); +} + +int bpf_get_next_key(int fd, void *key, void *next_key) +{ + return syscall(__NR_bpf, BPF_MAP_GET_NEXT_KEY, fd, key, next_key); +} + +#define ROUND_UP(x, n) (((x) + (n) - 1u) & ~((n) - 1u)) + +int bpf_prog_load(enum bpf_prog_type prog_type, + const struct bpf_insn *insns, int prog_len, + const char *license, + const struct bpf_map_fixup *fixups, int fixup_len) +{ + int nlattr_size, license_len, err; + void *nlattr, *ptr; + + license_len = strlen(license) + 1; + nlattr_size = sizeof(struct nlattr) + prog_len + sizeof(struct nlattr) + + ROUND_UP(license_len, 4) + sizeof(struct nlattr) + + fixup_len; + + ptr = nlattr = malloc(nlattr_size); + + *(struct nlattr *) ptr = (struct nlattr) { + .nla_len = prog_len + sizeof(struct nlattr), + .nla_type = BPF_PROG_TEXT, + }; + ptr += sizeof(struct nlattr); + + memcpy(ptr, insns, prog_len); + ptr += prog_len; + + *(struct nlattr *) ptr = (struct nlattr) { + .nla_len = ROUND_UP(license_len, 4) + sizeof(struct nlattr), + .nla_type = BPF_PROG_LICENSE, + }; + ptr += sizeof(struct nlattr); + + memcpy(ptr, license, license_len); + ptr += ROUND_UP(license_len, 4); + + *(struct nlattr *) ptr = (struct nlattr) { + .nla_len = fixup_len + sizeof(struct nlattr), + .nla_type = BPF_PROG_MAP_FIXUP, + }; + ptr += sizeof(struct nlattr); + + memcpy(ptr, fixups, fixup_len); + ptr += fixup_len; + + err = syscall(__NR_bpf, BPF_PROG_LOAD, prog_type, nlattr, nlattr_size); + + free(nlattr); + return err; +} diff --git a/samples/bpf/libbpf.h b/samples/bpf/libbpf.h new file mode 100644 index 000000000000..07f668e3dac0 --- /dev/null +++ b/samples/bpf/libbpf.h @@ -0,0 +1,22 @@ +/* eBPF mini library */ +#ifndef __LIBBPF_H +#define __LIBBPF_H + +struct bpf_insn; + +int bpf_create_map(int key_size, int value_size, int max_entries); +int bpf_update_elem(int fd, void *key, void *value); +int bpf_lookup_elem(int fd, void *key, void *value); +int bpf_delete_elem(int fd, void *key); +int bpf_get_next_key(int fd, void *key, void *next_key); + +struct bpf_map_fixup { + int insn_idx; + int fd; +}; +int bpf_prog_load(enum bpf_prog_type prog_type, + const struct bpf_insn *insns, int insn_len, + const char *license, + const struct bpf_map_fixup *fixups, int fixup_len); + +#endif -- 1.7.9.5