249b812d80
simple .o parser and loader using BPF syscall. .o is a standard ELF generated by LLVM backend It parses elf file compiled by llvm .c->.o - parses 'maps' section and creates maps via BPF syscall - parses 'license' section and passes it to syscall - parses elf relocations for BPF maps and adjusts BPF_LD_IMM64 insns by storing map_fd into insn->imm and marking such insns as BPF_PSEUDO_MAP_FD - loads eBPF programs via BPF syscall One ELF file can contain multiple BPF programs. int load_bpf_file(char *path); populates prog_fd[] and map_fd[] with FDs received from bpf syscall bpf_helpers.h - helper functions available to eBPF programs written in C Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
40 lines
1.3 KiB
C
40 lines
1.3 KiB
C
#ifndef __BPF_HELPERS_H
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#define __BPF_HELPERS_H
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/* helper macro to place programs, maps, license in
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* different sections in elf_bpf file. Section names
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* are interpreted by elf_bpf loader
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*/
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#define SEC(NAME) __attribute__((section(NAME), used))
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/* helper functions called from eBPF programs written in C */
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static void *(*bpf_map_lookup_elem)(void *map, void *key) =
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(void *) BPF_FUNC_map_lookup_elem;
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static int (*bpf_map_update_elem)(void *map, void *key, void *value,
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unsigned long long flags) =
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(void *) BPF_FUNC_map_update_elem;
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static int (*bpf_map_delete_elem)(void *map, void *key) =
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(void *) BPF_FUNC_map_delete_elem;
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/* llvm builtin functions that eBPF C program may use to
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* emit BPF_LD_ABS and BPF_LD_IND instructions
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*/
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struct sk_buff;
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unsigned long long load_byte(void *skb,
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unsigned long long off) asm("llvm.bpf.load.byte");
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unsigned long long load_half(void *skb,
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unsigned long long off) asm("llvm.bpf.load.half");
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unsigned long long load_word(void *skb,
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unsigned long long off) asm("llvm.bpf.load.word");
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/* a helper structure used by eBPF C program
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* to describe map attributes to elf_bpf loader
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*/
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struct bpf_map_def {
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unsigned int type;
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unsigned int key_size;
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unsigned int value_size;
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unsigned int max_entries;
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};
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#endif
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