1 /* 2 * common eBPF ELF operations. 3 * 4 * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org> 5 * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com> 6 * Copyright (C) 2015 Huawei Inc. 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; 11 * version 2.1 of the License (not later!) 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with this program; if not, see <http://www.gnu.org/licenses> 20 */ 21 22 #include <stdlib.h> 23 #include <memory.h> 24 #include <unistd.h> 25 #include <asm/unistd.h> 26 #include <linux/bpf.h> 27 #include "bpf.h" 28 29 /* 30 * When building perf, unistd.h is overrided. __NR_bpf is 31 * required to be defined explicitly. 32 */ 33 #ifndef __NR_bpf 34 # if defined(__i386__) 35 # define __NR_bpf 357 36 # elif defined(__x86_64__) 37 # define __NR_bpf 321 38 # elif defined(__aarch64__) 39 # define __NR_bpf 280 40 # else 41 # error __NR_bpf not defined. libbpf does not support your arch. 42 # endif 43 #endif 44 45 static __u64 ptr_to_u64(void *ptr) 46 { 47 return (__u64) (unsigned long) ptr; 48 } 49 50 static int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr, 51 unsigned int size) 52 { 53 return syscall(__NR_bpf, cmd, attr, size); 54 } 55 56 int bpf_create_map(enum bpf_map_type map_type, int key_size, 57 int value_size, int max_entries) 58 { 59 union bpf_attr attr; 60 61 memset(&attr, '\0', sizeof(attr)); 62 63 attr.map_type = map_type; 64 attr.key_size = key_size; 65 attr.value_size = value_size; 66 attr.max_entries = max_entries; 67 68 return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr)); 69 } 70 71 int bpf_load_program(enum bpf_prog_type type, struct bpf_insn *insns, 72 size_t insns_cnt, char *license, 73 u32 kern_version, char *log_buf, size_t log_buf_sz) 74 { 75 int fd; 76 union bpf_attr attr; 77 78 bzero(&attr, sizeof(attr)); 79 attr.prog_type = type; 80 attr.insn_cnt = (__u32)insns_cnt; 81 attr.insns = ptr_to_u64(insns); 82 attr.license = ptr_to_u64(license); 83 attr.log_buf = ptr_to_u64(NULL); 84 attr.log_size = 0; 85 attr.log_level = 0; 86 attr.kern_version = kern_version; 87 88 fd = sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr)); 89 if (fd >= 0 || !log_buf || !log_buf_sz) 90 return fd; 91 92 /* Try again with log */ 93 attr.log_buf = ptr_to_u64(log_buf); 94 attr.log_size = log_buf_sz; 95 attr.log_level = 1; 96 log_buf[0] = 0; 97 return sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr)); 98 } 99 100 int bpf_map_update_elem(int fd, void *key, void *value, 101 u64 flags) 102 { 103 union bpf_attr attr; 104 105 bzero(&attr, sizeof(attr)); 106 attr.map_fd = fd; 107 attr.key = ptr_to_u64(key); 108 attr.value = ptr_to_u64(value); 109 attr.flags = flags; 110 111 return sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr)); 112 } 113