1 // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
2 /* Copyright (c) 2019 Netronome Systems, Inc. */
3
4 #include <errno.h>
5 #include <fcntl.h>
6 #include <string.h>
7 #include <stdlib.h>
8 #include <unistd.h>
9 #include <net/if.h>
10 #include <sys/utsname.h>
11
12 #include <linux/btf.h>
13 #include <linux/filter.h>
14 #include <linux/kernel.h>
15
16 #include "bpf.h"
17 #include "libbpf.h"
18 #include "libbpf_internal.h"
19
grep(const char * buffer,const char * pattern)20 static bool grep(const char *buffer, const char *pattern)
21 {
22 return !!strstr(buffer, pattern);
23 }
24
get_vendor_id(int ifindex)25 static int get_vendor_id(int ifindex)
26 {
27 char ifname[IF_NAMESIZE], path[64], buf[8];
28 ssize_t len;
29 int fd;
30
31 if (!if_indextoname(ifindex, ifname))
32 return -1;
33
34 snprintf(path, sizeof(path), "/sys/class/net/%s/device/vendor", ifname);
35
36 fd = open(path, O_RDONLY);
37 if (fd < 0)
38 return -1;
39
40 len = read(fd, buf, sizeof(buf));
41 close(fd);
42 if (len < 0)
43 return -1;
44 if (len >= (ssize_t)sizeof(buf))
45 return -1;
46 buf[len] = '\0';
47
48 return strtol(buf, NULL, 0);
49 }
50
get_kernel_version(void)51 static int get_kernel_version(void)
52 {
53 int version, subversion, patchlevel;
54 struct utsname utsn;
55
56 /* Return 0 on failure, and attempt to probe with empty kversion */
57 if (uname(&utsn))
58 return 0;
59
60 if (sscanf(utsn.release, "%d.%d.%d",
61 &version, &subversion, &patchlevel) != 3)
62 return 0;
63
64 return (version << 16) + (subversion << 8) + patchlevel;
65 }
66
67 static void
probe_load(enum bpf_prog_type prog_type,const struct bpf_insn * insns,size_t insns_cnt,char * buf,size_t buf_len,__u32 ifindex)68 probe_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns,
69 size_t insns_cnt, char *buf, size_t buf_len, __u32 ifindex)
70 {
71 struct bpf_load_program_attr xattr = {};
72 int fd;
73
74 switch (prog_type) {
75 case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
76 xattr.expected_attach_type = BPF_CGROUP_INET4_CONNECT;
77 break;
78 case BPF_PROG_TYPE_CGROUP_SOCKOPT:
79 xattr.expected_attach_type = BPF_CGROUP_GETSOCKOPT;
80 break;
81 case BPF_PROG_TYPE_SK_LOOKUP:
82 xattr.expected_attach_type = BPF_SK_LOOKUP;
83 break;
84 case BPF_PROG_TYPE_KPROBE:
85 xattr.kern_version = get_kernel_version();
86 break;
87 case BPF_PROG_TYPE_UNSPEC:
88 case BPF_PROG_TYPE_SOCKET_FILTER:
89 case BPF_PROG_TYPE_SCHED_CLS:
90 case BPF_PROG_TYPE_SCHED_ACT:
91 case BPF_PROG_TYPE_TRACEPOINT:
92 case BPF_PROG_TYPE_XDP:
93 case BPF_PROG_TYPE_PERF_EVENT:
94 case BPF_PROG_TYPE_CGROUP_SKB:
95 case BPF_PROG_TYPE_CGROUP_SOCK:
96 case BPF_PROG_TYPE_LWT_IN:
97 case BPF_PROG_TYPE_LWT_OUT:
98 case BPF_PROG_TYPE_LWT_XMIT:
99 case BPF_PROG_TYPE_SOCK_OPS:
100 case BPF_PROG_TYPE_SK_SKB:
101 case BPF_PROG_TYPE_CGROUP_DEVICE:
102 case BPF_PROG_TYPE_SK_MSG:
103 case BPF_PROG_TYPE_RAW_TRACEPOINT:
104 case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
105 case BPF_PROG_TYPE_LWT_SEG6LOCAL:
106 case BPF_PROG_TYPE_LIRC_MODE2:
107 case BPF_PROG_TYPE_SK_REUSEPORT:
108 case BPF_PROG_TYPE_FLOW_DISSECTOR:
109 case BPF_PROG_TYPE_CGROUP_SYSCTL:
110 case BPF_PROG_TYPE_TRACING:
111 case BPF_PROG_TYPE_STRUCT_OPS:
112 case BPF_PROG_TYPE_EXT:
113 case BPF_PROG_TYPE_LSM:
114 default:
115 break;
116 }
117
118 xattr.prog_type = prog_type;
119 xattr.insns = insns;
120 xattr.insns_cnt = insns_cnt;
121 xattr.license = "GPL";
122 xattr.prog_ifindex = ifindex;
123
124 fd = bpf_load_program_xattr(&xattr, buf, buf_len);
125 if (fd >= 0)
126 close(fd);
127 }
128
bpf_probe_prog_type(enum bpf_prog_type prog_type,__u32 ifindex)129 bool bpf_probe_prog_type(enum bpf_prog_type prog_type, __u32 ifindex)
130 {
131 struct bpf_insn insns[2] = {
132 BPF_MOV64_IMM(BPF_REG_0, 0),
133 BPF_EXIT_INSN()
134 };
135
136 if (ifindex && prog_type == BPF_PROG_TYPE_SCHED_CLS)
137 /* nfp returns -EINVAL on exit(0) with TC offload */
138 insns[0].imm = 2;
139
140 errno = 0;
141 probe_load(prog_type, insns, ARRAY_SIZE(insns), NULL, 0, ifindex);
142
143 return errno != EINVAL && errno != EOPNOTSUPP;
144 }
145
libbpf__load_raw_btf(const char * raw_types,size_t types_len,const char * str_sec,size_t str_len)146 int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
147 const char *str_sec, size_t str_len)
148 {
149 struct btf_header hdr = {
150 .magic = BTF_MAGIC,
151 .version = BTF_VERSION,
152 .hdr_len = sizeof(struct btf_header),
153 .type_len = types_len,
154 .str_off = types_len,
155 .str_len = str_len,
156 };
157 int btf_fd, btf_len;
158 __u8 *raw_btf;
159
160 btf_len = hdr.hdr_len + hdr.type_len + hdr.str_len;
161 raw_btf = malloc(btf_len);
162 if (!raw_btf)
163 return -ENOMEM;
164
165 memcpy(raw_btf, &hdr, sizeof(hdr));
166 memcpy(raw_btf + hdr.hdr_len, raw_types, hdr.type_len);
167 memcpy(raw_btf + hdr.hdr_len + hdr.type_len, str_sec, hdr.str_len);
168
169 btf_fd = bpf_load_btf(raw_btf, btf_len, NULL, 0, false);
170
171 free(raw_btf);
172 return btf_fd;
173 }
174
load_local_storage_btf(void)175 static int load_local_storage_btf(void)
176 {
177 const char strs[] = "\0bpf_spin_lock\0val\0cnt\0l";
178 /* struct bpf_spin_lock {
179 * int val;
180 * };
181 * struct val {
182 * int cnt;
183 * struct bpf_spin_lock l;
184 * };
185 */
186 __u32 types[] = {
187 /* int */
188 BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
189 /* struct bpf_spin_lock */ /* [2] */
190 BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4),
191 BTF_MEMBER_ENC(15, 1, 0), /* int val; */
192 /* struct val */ /* [3] */
193 BTF_TYPE_ENC(15, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 2), 8),
194 BTF_MEMBER_ENC(19, 1, 0), /* int cnt; */
195 BTF_MEMBER_ENC(23, 2, 32),/* struct bpf_spin_lock l; */
196 };
197
198 return libbpf__load_raw_btf((char *)types, sizeof(types),
199 strs, sizeof(strs));
200 }
201
bpf_probe_map_type(enum bpf_map_type map_type,__u32 ifindex)202 bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex)
203 {
204 int key_size, value_size, max_entries, map_flags;
205 __u32 btf_key_type_id = 0, btf_value_type_id = 0;
206 struct bpf_create_map_attr attr = {};
207 int fd = -1, btf_fd = -1, fd_inner;
208
209 key_size = sizeof(__u32);
210 value_size = sizeof(__u32);
211 max_entries = 1;
212 map_flags = 0;
213
214 switch (map_type) {
215 case BPF_MAP_TYPE_STACK_TRACE:
216 value_size = sizeof(__u64);
217 break;
218 case BPF_MAP_TYPE_LPM_TRIE:
219 key_size = sizeof(__u64);
220 value_size = sizeof(__u64);
221 map_flags = BPF_F_NO_PREALLOC;
222 break;
223 case BPF_MAP_TYPE_CGROUP_STORAGE:
224 case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
225 key_size = sizeof(struct bpf_cgroup_storage_key);
226 value_size = sizeof(__u64);
227 max_entries = 0;
228 break;
229 case BPF_MAP_TYPE_QUEUE:
230 case BPF_MAP_TYPE_STACK:
231 key_size = 0;
232 break;
233 case BPF_MAP_TYPE_SK_STORAGE:
234 case BPF_MAP_TYPE_INODE_STORAGE:
235 btf_key_type_id = 1;
236 btf_value_type_id = 3;
237 value_size = 8;
238 max_entries = 0;
239 map_flags = BPF_F_NO_PREALLOC;
240 btf_fd = load_local_storage_btf();
241 if (btf_fd < 0)
242 return false;
243 break;
244 case BPF_MAP_TYPE_RINGBUF:
245 key_size = 0;
246 value_size = 0;
247 max_entries = sysconf(_SC_PAGE_SIZE);
248 break;
249 case BPF_MAP_TYPE_UNSPEC:
250 case BPF_MAP_TYPE_HASH:
251 case BPF_MAP_TYPE_ARRAY:
252 case BPF_MAP_TYPE_PROG_ARRAY:
253 case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
254 case BPF_MAP_TYPE_PERCPU_HASH:
255 case BPF_MAP_TYPE_PERCPU_ARRAY:
256 case BPF_MAP_TYPE_CGROUP_ARRAY:
257 case BPF_MAP_TYPE_LRU_HASH:
258 case BPF_MAP_TYPE_LRU_PERCPU_HASH:
259 case BPF_MAP_TYPE_ARRAY_OF_MAPS:
260 case BPF_MAP_TYPE_HASH_OF_MAPS:
261 case BPF_MAP_TYPE_DEVMAP:
262 case BPF_MAP_TYPE_DEVMAP_HASH:
263 case BPF_MAP_TYPE_SOCKMAP:
264 case BPF_MAP_TYPE_CPUMAP:
265 case BPF_MAP_TYPE_XSKMAP:
266 case BPF_MAP_TYPE_SOCKHASH:
267 case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
268 case BPF_MAP_TYPE_STRUCT_OPS:
269 default:
270 break;
271 }
272
273 if (map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
274 map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
275 /* TODO: probe for device, once libbpf has a function to create
276 * map-in-map for offload
277 */
278 if (ifindex)
279 return false;
280
281 fd_inner = bpf_create_map(BPF_MAP_TYPE_HASH,
282 sizeof(__u32), sizeof(__u32), 1, 0);
283 if (fd_inner < 0)
284 return false;
285 fd = bpf_create_map_in_map(map_type, NULL, sizeof(__u32),
286 fd_inner, 1, 0);
287 close(fd_inner);
288 } else {
289 /* Note: No other restriction on map type probes for offload */
290 attr.map_type = map_type;
291 attr.key_size = key_size;
292 attr.value_size = value_size;
293 attr.max_entries = max_entries;
294 attr.map_flags = map_flags;
295 attr.map_ifindex = ifindex;
296 if (btf_fd >= 0) {
297 attr.btf_fd = btf_fd;
298 attr.btf_key_type_id = btf_key_type_id;
299 attr.btf_value_type_id = btf_value_type_id;
300 }
301
302 fd = bpf_create_map_xattr(&attr);
303 }
304 if (fd >= 0)
305 close(fd);
306 if (btf_fd >= 0)
307 close(btf_fd);
308
309 return fd >= 0;
310 }
311
bpf_probe_helper(enum bpf_func_id id,enum bpf_prog_type prog_type,__u32 ifindex)312 bool bpf_probe_helper(enum bpf_func_id id, enum bpf_prog_type prog_type,
313 __u32 ifindex)
314 {
315 struct bpf_insn insns[2] = {
316 BPF_EMIT_CALL(id),
317 BPF_EXIT_INSN()
318 };
319 char buf[4096] = {};
320 bool res;
321
322 probe_load(prog_type, insns, ARRAY_SIZE(insns), buf, sizeof(buf),
323 ifindex);
324 res = !grep(buf, "invalid func ") && !grep(buf, "unknown func ");
325
326 if (ifindex) {
327 switch (get_vendor_id(ifindex)) {
328 case 0x19ee: /* Netronome specific */
329 res = res && !grep(buf, "not supported by FW") &&
330 !grep(buf, "unsupported function id");
331 break;
332 default:
333 break;
334 }
335 }
336
337 return res;
338 }
339
340 /*
341 * Probe for availability of kernel commit (5.3):
342 *
343 * c04c0d2b968a ("bpf: increase complexity limit and maximum program size")
344 */
bpf_probe_large_insn_limit(__u32 ifindex)345 bool bpf_probe_large_insn_limit(__u32 ifindex)
346 {
347 struct bpf_insn insns[BPF_MAXINSNS + 1];
348 int i;
349
350 for (i = 0; i < BPF_MAXINSNS; i++)
351 insns[i] = BPF_MOV64_IMM(BPF_REG_0, 1);
352 insns[BPF_MAXINSNS] = BPF_EXIT_INSN();
353
354 errno = 0;
355 probe_load(BPF_PROG_TYPE_SCHED_CLS, insns, ARRAY_SIZE(insns), NULL, 0,
356 ifindex);
357
358 return errno != E2BIG && errno != EINVAL;
359 }
360