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 overridden. __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 inline __u64 ptr_to_u64(const void *ptr) 46 { 47 return (__u64) (unsigned long) ptr; 48 } 49 50 static inline 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, __u32 map_flags) 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 attr.map_flags = map_flags; 68 69 return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr)); 70 } 71 72 int bpf_load_program(enum bpf_prog_type type, const struct bpf_insn *insns, 73 size_t insns_cnt, const char *license, 74 __u32 kern_version, char *log_buf, size_t log_buf_sz) 75 { 76 int fd; 77 union bpf_attr attr; 78 79 bzero(&attr, sizeof(attr)); 80 attr.prog_type = type; 81 attr.insn_cnt = (__u32)insns_cnt; 82 attr.insns = ptr_to_u64(insns); 83 attr.license = ptr_to_u64(license); 84 attr.log_buf = ptr_to_u64(NULL); 85 attr.log_size = 0; 86 attr.log_level = 0; 87 attr.kern_version = kern_version; 88 89 fd = sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr)); 90 if (fd >= 0 || !log_buf || !log_buf_sz) 91 return fd; 92 93 /* Try again with log */ 94 attr.log_buf = ptr_to_u64(log_buf); 95 attr.log_size = log_buf_sz; 96 attr.log_level = 1; 97 log_buf[0] = 0; 98 return sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr)); 99 } 100 101 int bpf_map_update_elem(int fd, const void *key, const void *value, 102 __u64 flags) 103 { 104 union bpf_attr attr; 105 106 bzero(&attr, sizeof(attr)); 107 attr.map_fd = fd; 108 attr.key = ptr_to_u64(key); 109 attr.value = ptr_to_u64(value); 110 attr.flags = flags; 111 112 return sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr)); 113 } 114 115 int bpf_map_lookup_elem(int fd, const void *key, void *value) 116 { 117 union bpf_attr attr; 118 119 bzero(&attr, sizeof(attr)); 120 attr.map_fd = fd; 121 attr.key = ptr_to_u64(key); 122 attr.value = ptr_to_u64(value); 123 124 return sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr)); 125 } 126 127 int bpf_map_delete_elem(int fd, const void *key) 128 { 129 union bpf_attr attr; 130 131 bzero(&attr, sizeof(attr)); 132 attr.map_fd = fd; 133 attr.key = ptr_to_u64(key); 134 135 return sys_bpf(BPF_MAP_DELETE_ELEM, &attr, sizeof(attr)); 136 } 137 138 int bpf_map_get_next_key(int fd, const void *key, void *next_key) 139 { 140 union bpf_attr attr; 141 142 bzero(&attr, sizeof(attr)); 143 attr.map_fd = fd; 144 attr.key = ptr_to_u64(key); 145 attr.next_key = ptr_to_u64(next_key); 146 147 return sys_bpf(BPF_MAP_GET_NEXT_KEY, &attr, sizeof(attr)); 148 } 149 150 int bpf_obj_pin(int fd, const char *pathname) 151 { 152 union bpf_attr attr; 153 154 bzero(&attr, sizeof(attr)); 155 attr.pathname = ptr_to_u64((void *)pathname); 156 attr.bpf_fd = fd; 157 158 return sys_bpf(BPF_OBJ_PIN, &attr, sizeof(attr)); 159 } 160 161 int bpf_obj_get(const char *pathname) 162 { 163 union bpf_attr attr; 164 165 bzero(&attr, sizeof(attr)); 166 attr.pathname = ptr_to_u64((void *)pathname); 167 168 return sys_bpf(BPF_OBJ_GET, &attr, sizeof(attr)); 169 } 170 171 int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type, 172 unsigned int flags) 173 { 174 union bpf_attr attr; 175 176 bzero(&attr, sizeof(attr)); 177 attr.target_fd = target_fd; 178 attr.attach_bpf_fd = prog_fd; 179 attr.attach_type = type; 180 attr.attach_flags = flags; 181 182 return sys_bpf(BPF_PROG_ATTACH, &attr, sizeof(attr)); 183 } 184 185 int bpf_prog_detach(int target_fd, enum bpf_attach_type type) 186 { 187 union bpf_attr attr; 188 189 bzero(&attr, sizeof(attr)); 190 attr.target_fd = target_fd; 191 attr.attach_type = type; 192 193 return sys_bpf(BPF_PROG_DETACH, &attr, sizeof(attr)); 194 } 195