From 09756af46893c18839062976c3252e93a1beeba7 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Fri, 26 Sep 2014 00:17:00 -0700 Subject: bpf: expand BPF syscall with program load/unload eBPF programs are similar to kernel modules. They are loaded by the user process and automatically unloaded when process exits. Each eBPF program is a safe run-to-completion set of instructions. eBPF verifier statically determines that the program terminates and is safe to execute. The following syscall wrapper can be used to load the program: int bpf_prog_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns, int insn_cnt, const char *license) { union bpf_attr attr = { .prog_type = prog_type, .insns = ptr_to_u64(insns), .insn_cnt = insn_cnt, .license = ptr_to_u64(license), }; return bpf(BPF_PROG_LOAD, &attr, sizeof(attr)); } where 'insns' is an array of eBPF instructions and 'license' is a string that must be GPL compatible to call helper functions marked gpl_only Upon succesful load the syscall returns prog_fd. Use close(prog_fd) to unload the program. User space tests and examples follow in the later patches Signed-off-by: Alexei Starovoitov Signed-off-by: David S. Miller --- include/uapi/linux/bpf.h | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'include/uapi/linux/bpf.h') diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 395cabd2ca0a..424f442016e7 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -99,12 +99,23 @@ enum bpf_cmd { * returns zero and stores next key or negative error */ BPF_MAP_GET_NEXT_KEY, + + /* verify and load eBPF program + * prog_fd = bpf(BPF_PROG_LOAD, union bpf_attr *attr, u32 size) + * Using attr->prog_type, attr->insns, attr->license + * returns fd or negative error + */ + BPF_PROG_LOAD, }; enum bpf_map_type { BPF_MAP_TYPE_UNSPEC, }; +enum bpf_prog_type { + BPF_PROG_TYPE_UNSPEC, +}; + union bpf_attr { struct { /* anonymous struct used by BPF_MAP_CREATE command */ __u32 map_type; /* one of enum bpf_map_type */ @@ -121,6 +132,21 @@ union bpf_attr { __aligned_u64 next_key; }; }; + + struct { /* anonymous struct used by BPF_PROG_LOAD command */ + __u32 prog_type; /* one of enum bpf_prog_type */ + __u32 insn_cnt; + __aligned_u64 insns; + __aligned_u64 license; + }; } __attribute__((aligned(8))); +/* integer value in 'imm' field of BPF_CALL instruction selects which helper + * function eBPF program intends to call + */ +enum bpf_func_id { + BPF_FUNC_unspec, + __BPF_FUNC_MAX_ID, +}; + #endif /* _UAPI__LINUX_BPF_H__ */ -- cgit v1.2.3