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 #ifndef LOG_TAG
18 #define LOG_TAG "bpfloader"
19 #endif
20
21 #include <arpa/inet.h>
22 #include <dirent.h>
23 #include <elf.h>
24 #include <error.h>
25 #include <fcntl.h>
26 #include <inttypes.h>
27 #include <linux/bpf.h>
28 #include <linux/unistd.h>
29 #include <net/if.h>
30 #include <stdint.h>
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <unistd.h>
35
36 #include <sys/mman.h>
37 #include <sys/socket.h>
38 #include <sys/stat.h>
39 #include <sys/types.h>
40
41 #include <android-base/properties.h>
42 #include <android-base/stringprintf.h>
43 #include <android-base/strings.h>
44 #include <android-base/unique_fd.h>
45 #include <libbpf_android.h>
46 #include <log/log.h>
47 #include <netdutils/Misc.h>
48 #include <netdutils/Slice.h>
49 #include "bpf/BpfUtils.h"
50
51 using android::base::EndsWith;
52 using std::string;
53
54 struct {
55 const char* const dir;
56 const char* const prefix;
57 } locations[] = {
58 // Tethering mainline module
59 {
60 .dir = "/apex/com.android.tethering/etc/bpf/",
61 .prefix = "tethering/",
62 },
63 // Core operating system
64 {
65 .dir = "/system/etc/bpf/",
66 .prefix = "",
67 },
68 };
69
loadAllElfObjects(const char * const progDir,const char * const prefix)70 int loadAllElfObjects(const char* const progDir, const char* const prefix) {
71 int retVal = 0;
72 DIR* dir;
73 struct dirent* ent;
74
75 if ((dir = opendir(progDir)) != NULL) {
76 while ((ent = readdir(dir)) != NULL) {
77 string s = ent->d_name;
78 if (!EndsWith(s, ".o")) continue;
79
80 string progPath(progDir);
81 progPath += s;
82
83 bool critical;
84 int ret = android::bpf::loadProg(progPath.c_str(), &critical, prefix);
85 if (ret) {
86 if (critical) retVal = ret;
87 ALOGE("Failed to load object: %s, ret: %s", progPath.c_str(), std::strerror(-ret));
88 } else {
89 ALOGI("Loaded object: %s", progPath.c_str());
90 }
91 }
92 closedir(dir);
93 }
94 return retVal;
95 }
96
createSysFsBpfSubDir(const char * const prefix)97 void createSysFsBpfSubDir(const char* const prefix) {
98 if (*prefix) {
99 mode_t prevUmask = umask(0);
100
101 string s = "/sys/fs/bpf/";
102 s += prefix;
103
104 errno = 0;
105 int ret = mkdir(s.c_str(), S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO);
106 if (ret && errno != EEXIST) {
107 ALOGW("Failed to create directory: %s, ret: %s", s.c_str(), std::strerror(errno));
108 }
109
110 umask(prevUmask);
111 }
112 }
113
main()114 int main() {
115 // Load all ELF objects, create programs and maps, and pin them
116 for (const auto location : locations) {
117 createSysFsBpfSubDir(location.prefix);
118 if (loadAllElfObjects(location.dir, location.prefix) != 0) {
119 ALOGE("=== CRITICAL FAILURE LOADING BPF PROGRAMS FROM %s ===", location.dir);
120 ALOGE("If this triggers reliably, you're probably missing kernel options or patches.");
121 ALOGE("If this triggers randomly, you might be hitting some memory allocation "
122 "problems or startup script race.");
123 ALOGE("--- DO NOT EXPECT SYSTEM TO BOOT SUCCESSFULLY ---");
124 sleep(20);
125 return 2;
126 }
127 }
128
129 if (android::base::SetProperty("bpf.progs_loaded", "1") == false) {
130 ALOGE("Failed to set bpf.progs_loaded property");
131 return 1;
132 }
133
134 return 0;
135 }
136