1 /* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include <linux/bpf.h> 18 #include <linux/if_ether.h> 19 #include <linux/in.h> 20 #include <stdlib.h> 21 #include <string.h> 22 #include <inttypes.h> 23 #include <sys/socket.h> 24 #include <sys/stat.h> 25 #include <sys/utsname.h> 26 #include <sstream> 27 #include <string> 28 29 #include <android-base/properties.h> 30 #include <android-base/stringprintf.h> 31 #include <android-base/unique_fd.h> 32 #include <netdutils/Slice.h> 33 #include <netdutils/StatusOr.h> 34 #include "bpf/BpfUtils.h" 35 36 using android::base::StringPrintf; 37 using android::base::unique_fd; 38 using android::base::GetUintProperty; 39 using android::netdutils::Slice; 40 using android::netdutils::statusFromErrno; 41 using android::netdutils::StatusOr; 42 43 #define ptr_to_u64(x) ((uint64_t)(uintptr_t)x) 44 #define DEFAULT_LOG_LEVEL 1 45 46 namespace android { 47 namespace bpf { 48 49 /* The bpf_attr is a union which might have a much larger size then the struct we are using, while 50 * The inline initializer only reset the field we are using and leave the reset of the memory as 51 * is. The bpf kernel code will performs a much stricter check to ensure all unused field is 0. So 52 * this syscall will normally fail with E2BIG if we don't do a memset to bpf_attr. 53 */ 54 bool operator==(const StatsKey& lhs, const StatsKey& rhs) { 55 return ((lhs.uid == rhs.uid) && (lhs.tag == rhs.tag) && (lhs.counterSet == rhs.counterSet) && 56 (lhs.ifaceIndex == rhs.ifaceIndex)); 57 } 58 59 bool operator==(const UidTag& lhs, const UidTag& rhs) { 60 return ((lhs.uid == rhs.uid) && (lhs.tag == rhs.tag)); 61 } 62 63 bool operator==(const StatsValue& lhs, const StatsValue& rhs) { 64 return ((lhs.rxBytes == rhs.rxBytes) && (lhs.txBytes == rhs.txBytes) && 65 (lhs.rxPackets == rhs.rxPackets) && (lhs.txPackets == rhs.txPackets)); 66 } 67 68 int bpf(int cmd, Slice bpfAttr) { 69 return syscall(__NR_bpf, cmd, bpfAttr.base(), bpfAttr.size()); 70 } 71 72 int createMap(bpf_map_type map_type, uint32_t key_size, uint32_t value_size, uint32_t max_entries, 73 uint32_t map_flags) { 74 bpf_attr attr; 75 memset(&attr, 0, sizeof(attr)); 76 attr.map_type = map_type; 77 attr.key_size = key_size; 78 attr.value_size = value_size; 79 attr.max_entries = max_entries; 80 attr.map_flags = map_flags; 81 82 return bpf(BPF_MAP_CREATE, Slice(&attr, sizeof(attr))); 83 } 84 85 int writeToMapEntry(const base::unique_fd& map_fd, void* key, void* value, uint64_t flags) { 86 bpf_attr attr; 87 memset(&attr, 0, sizeof(attr)); 88 attr.map_fd = map_fd.get(); 89 attr.key = ptr_to_u64(key); 90 attr.value = ptr_to_u64(value); 91 attr.flags = flags; 92 93 return bpf(BPF_MAP_UPDATE_ELEM, Slice(&attr, sizeof(attr))); 94 } 95 96 int findMapEntry(const base::unique_fd& map_fd, void* key, void* value) { 97 bpf_attr attr; 98 memset(&attr, 0, sizeof(attr)); 99 attr.map_fd = map_fd.get(); 100 attr.key = ptr_to_u64(key); 101 attr.value = ptr_to_u64(value); 102 103 return bpf(BPF_MAP_LOOKUP_ELEM, Slice(&attr, sizeof(attr))); 104 } 105 106 int deleteMapEntry(const base::unique_fd& map_fd, void* key) { 107 bpf_attr attr; 108 memset(&attr, 0, sizeof(attr)); 109 attr.map_fd = map_fd.get(); 110 attr.key = ptr_to_u64(key); 111 112 return bpf(BPF_MAP_DELETE_ELEM, Slice(&attr, sizeof(attr))); 113 } 114 115 int getNextMapKey(const base::unique_fd& map_fd, void* key, void* next_key) { 116 bpf_attr attr; 117 memset(&attr, 0, sizeof(attr)); 118 attr.map_fd = map_fd.get(); 119 attr.key = ptr_to_u64(key); 120 attr.next_key = ptr_to_u64(next_key); 121 122 return bpf(BPF_MAP_GET_NEXT_KEY, Slice(&attr, sizeof(attr))); 123 } 124 125 int getFirstMapKey(const base::unique_fd& map_fd, void* firstKey) { 126 bpf_attr attr; 127 memset(&attr, 0, sizeof(attr)); 128 attr.map_fd = map_fd.get(); 129 attr.key = 0; 130 attr.next_key = ptr_to_u64(firstKey); 131 132 return bpf(BPF_MAP_GET_NEXT_KEY, Slice(&attr, sizeof(attr))); 133 } 134 135 int bpfProgLoad(bpf_prog_type prog_type, Slice bpf_insns, const char* license, 136 uint32_t kern_version, Slice bpf_log) { 137 bpf_attr attr; 138 memset(&attr, 0, sizeof(attr)); 139 attr.prog_type = prog_type; 140 attr.insns = ptr_to_u64(bpf_insns.base()); 141 attr.insn_cnt = bpf_insns.size() / sizeof(struct bpf_insn); 142 attr.license = ptr_to_u64((void*)license); 143 attr.log_buf = ptr_to_u64(bpf_log.base()); 144 attr.log_size = bpf_log.size(); 145 attr.log_level = DEFAULT_LOG_LEVEL; 146 attr.kern_version = kern_version; 147 int ret = bpf(BPF_PROG_LOAD, Slice(&attr, sizeof(attr))); 148 149 if (ret < 0) { 150 std::string prog_log = netdutils::toString(bpf_log); 151 std::istringstream iss(prog_log); 152 for (std::string line; std::getline(iss, line);) { 153 ALOGE("%s", line.c_str()); 154 } 155 } 156 return ret; 157 } 158 159 int mapPin(const base::unique_fd& map_fd, const char* pathname) { 160 bpf_attr attr; 161 memset(&attr, 0, sizeof(attr)); 162 attr.pathname = ptr_to_u64((void*)pathname); 163 attr.bpf_fd = map_fd.get(); 164 165 return bpf(BPF_OBJ_PIN, Slice(&attr, sizeof(attr))); 166 } 167 168 int mapRetrieve(const char* pathname, uint32_t flag) { 169 bpf_attr attr; 170 memset(&attr, 0, sizeof(attr)); 171 attr.pathname = ptr_to_u64((void*)pathname); 172 attr.file_flags = flag; 173 return bpf(BPF_OBJ_GET, Slice(&attr, sizeof(attr))); 174 } 175 176 int attachProgram(bpf_attach_type type, uint32_t prog_fd, uint32_t cg_fd) { 177 bpf_attr attr; 178 memset(&attr, 0, sizeof(attr)); 179 attr.target_fd = cg_fd; 180 attr.attach_bpf_fd = prog_fd; 181 attr.attach_type = type; 182 183 return bpf(BPF_PROG_ATTACH, Slice(&attr, sizeof(attr))); 184 } 185 186 int detachProgram(bpf_attach_type type, uint32_t cg_fd) { 187 bpf_attr attr; 188 memset(&attr, 0, sizeof(attr)); 189 attr.target_fd = cg_fd; 190 attr.attach_type = type; 191 192 return bpf(BPF_PROG_DETACH, Slice(&attr, sizeof(attr))); 193 } 194 195 uint64_t getSocketCookie(int sockFd) { 196 uint64_t sock_cookie; 197 socklen_t cookie_len = sizeof(sock_cookie); 198 int res = getsockopt(sockFd, SOL_SOCKET, SO_COOKIE, &sock_cookie, &cookie_len); 199 if (res < 0) { 200 res = -errno; 201 ALOGE("Failed to get socket cookie: %s\n", strerror(errno)); 202 errno = -res; 203 // 0 is an invalid cookie. See sock_gen_cookie. 204 return NONEXISTENT_COOKIE; 205 } 206 return sock_cookie; 207 } 208 209 bool hasBpfSupport() { 210 struct utsname buf; 211 int kernel_version_major; 212 int kernel_version_minor; 213 214 uint64_t api_level = GetUintProperty<uint64_t>("ro.product.first_api_level", 0); 215 if (api_level == 0) { 216 ALOGE("Cannot determine initial API level of the device"); 217 api_level = GetUintProperty<uint64_t>("ro.build.version.sdk", 0); 218 } 219 220 int ret = uname(&buf); 221 if (ret) { 222 return false; 223 } 224 char dummy; 225 ret = sscanf(buf.release, "%d.%d%c", &kernel_version_major, &kernel_version_minor, &dummy); 226 if (ret >= 2 && ((kernel_version_major > 4) || 227 (kernel_version_major == 4 && kernel_version_minor >= 9))) { 228 // Check if the device is shipped originally with android P. 229 return api_level >= MINIMUM_API_REQUIRED; 230 } 231 return false; 232 } 233 234 } // namespace bpf 235 } // namespace android 236
