tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
20/* make sure libbpf doesn't use kernel-only integer typedefs */
21#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
22
23static bool grep(const char *buffer, const char *pattern)
24{
25 return !!strstr(buffer, pattern);
26}
27
28static int get_vendor_id(int ifindex)
29{
30 char ifname[IF_NAMESIZE], path[64], buf[8];
31 ssize_t len;
32 int fd;
33
34 if (!if_indextoname(ifindex, ifname))
35 return -1;
36
37 snprintf(path, sizeof(path), "/sys/class/net/%s/device/vendor", ifname);
38
39 fd = open(path, O_RDONLY);
40 if (fd < 0)
41 return -1;
42
43 len = read(fd, buf, sizeof(buf));
44 close(fd);
45 if (len < 0)
46 return -1;
47 if (len >= (ssize_t)sizeof(buf))
48 return -1;
49 buf[len] = '\0';
50
51 return strtol(buf, NULL, 0);
52}
53
54static int get_kernel_version(void)
55{
56 int version, subversion, patchlevel;
57 struct utsname utsn;
58
59 /* Return 0 on failure, and attempt to probe with empty kversion */
60 if (uname(&utsn))
61 return 0;
62
63 if (sscanf(utsn.release, "%d.%d.%d",
64 &version, &subversion, &patchlevel) != 3)
65 return 0;
66
67 return (version << 16) + (subversion << 8) + patchlevel;
68}
69
70static void
71probe_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns,
72 size_t insns_cnt, char *buf, size_t buf_len, __u32 ifindex)
73{
74 struct bpf_load_program_attr xattr = {};
75 int fd;
76
77 switch (prog_type) {
78 case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
79 xattr.expected_attach_type = BPF_CGROUP_INET4_CONNECT;
80 break;
81 case BPF_PROG_TYPE_KPROBE:
82 xattr.kern_version = get_kernel_version();
83 break;
84 case BPF_PROG_TYPE_UNSPEC:
85 case BPF_PROG_TYPE_SOCKET_FILTER:
86 case BPF_PROG_TYPE_SCHED_CLS:
87 case BPF_PROG_TYPE_SCHED_ACT:
88 case BPF_PROG_TYPE_TRACEPOINT:
89 case BPF_PROG_TYPE_XDP:
90 case BPF_PROG_TYPE_PERF_EVENT:
91 case BPF_PROG_TYPE_CGROUP_SKB:
92 case BPF_PROG_TYPE_CGROUP_SOCK:
93 case BPF_PROG_TYPE_LWT_IN:
94 case BPF_PROG_TYPE_LWT_OUT:
95 case BPF_PROG_TYPE_LWT_XMIT:
96 case BPF_PROG_TYPE_SOCK_OPS:
97 case BPF_PROG_TYPE_SK_SKB:
98 case BPF_PROG_TYPE_CGROUP_DEVICE:
99 case BPF_PROG_TYPE_SK_MSG:
100 case BPF_PROG_TYPE_RAW_TRACEPOINT:
101 case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
102 case BPF_PROG_TYPE_LWT_SEG6LOCAL:
103 case BPF_PROG_TYPE_LIRC_MODE2:
104 case BPF_PROG_TYPE_SK_REUSEPORT:
105 case BPF_PROG_TYPE_FLOW_DISSECTOR:
106 case BPF_PROG_TYPE_CGROUP_SYSCTL:
107 case BPF_PROG_TYPE_CGROUP_SOCKOPT:
108 case BPF_PROG_TYPE_TRACING:
109 case BPF_PROG_TYPE_STRUCT_OPS:
110 case BPF_PROG_TYPE_EXT:
111 case BPF_PROG_TYPE_LSM:
112 default:
113 break;
114 }
115
116 xattr.prog_type = prog_type;
117 xattr.insns = insns;
118 xattr.insns_cnt = insns_cnt;
119 xattr.license = "GPL";
120 xattr.prog_ifindex = ifindex;
121
122 fd = bpf_load_program_xattr(&xattr, buf, buf_len);
123 if (fd >= 0)
124 close(fd);
125}
126
127bool bpf_probe_prog_type(enum bpf_prog_type prog_type, __u32 ifindex)
128{
129 struct bpf_insn insns[2] = {
130 BPF_MOV64_IMM(BPF_REG_0, 0),
131 BPF_EXIT_INSN()
132 };
133
134 if (ifindex && prog_type == BPF_PROG_TYPE_SCHED_CLS)
135 /* nfp returns -EINVAL on exit(0) with TC offload */
136 insns[0].imm = 2;
137
138 errno = 0;
139 probe_load(prog_type, insns, ARRAY_SIZE(insns), NULL, 0, ifindex);
140
141 return errno != EINVAL && errno != EOPNOTSUPP;
142}
143
144int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
145 const char *str_sec, size_t str_len)
146{
147 struct btf_header hdr = {
148 .magic = BTF_MAGIC,
149 .version = BTF_VERSION,
150 .hdr_len = sizeof(struct btf_header),
151 .type_len = types_len,
152 .str_off = types_len,
153 .str_len = str_len,
154 };
155 int btf_fd, btf_len;
156 __u8 *raw_btf;
157
158 btf_len = hdr.hdr_len + hdr.type_len + hdr.str_len;
159 raw_btf = malloc(btf_len);
160 if (!raw_btf)
161 return -ENOMEM;
162
163 memcpy(raw_btf, &hdr, sizeof(hdr));
164 memcpy(raw_btf + hdr.hdr_len, raw_types, hdr.type_len);
165 memcpy(raw_btf + hdr.hdr_len + hdr.type_len, str_sec, hdr.str_len);
166
167 btf_fd = bpf_load_btf(raw_btf, btf_len, NULL, 0, false);
168
169 free(raw_btf);
170 return btf_fd;
171}
172
173static int load_sk_storage_btf(void)
174{
175 const char strs[] = "\0bpf_spin_lock\0val\0cnt\0l";
176 /* struct bpf_spin_lock {
177 * int val;
178 * };
179 * struct val {
180 * int cnt;
181 * struct bpf_spin_lock l;
182 * };
183 */
184 __u32 types[] = {
185 /* int */
186 BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
187 /* struct bpf_spin_lock */ /* [2] */
188 BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4),
189 BTF_MEMBER_ENC(15, 1, 0), /* int val; */
190 /* struct val */ /* [3] */
191 BTF_TYPE_ENC(15, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 2), 8),
192 BTF_MEMBER_ENC(19, 1, 0), /* int cnt; */
193 BTF_MEMBER_ENC(23, 2, 32),/* struct bpf_spin_lock l; */
194 };
195
196 return libbpf__load_raw_btf((char *)types, sizeof(types),
197 strs, sizeof(strs));
198}
199
200bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex)
201{
202 int key_size, value_size, max_entries, map_flags;
203 __u32 btf_key_type_id = 0, btf_value_type_id = 0;
204 struct bpf_create_map_attr attr = {};
205 int fd = -1, btf_fd = -1, fd_inner;
206
207 key_size = sizeof(__u32);
208 value_size = sizeof(__u32);
209 max_entries = 1;
210 map_flags = 0;
211
212 switch (map_type) {
213 case BPF_MAP_TYPE_STACK_TRACE:
214 value_size = sizeof(__u64);
215 break;
216 case BPF_MAP_TYPE_LPM_TRIE:
217 key_size = sizeof(__u64);
218 value_size = sizeof(__u64);
219 map_flags = BPF_F_NO_PREALLOC;
220 break;
221 case BPF_MAP_TYPE_CGROUP_STORAGE:
222 case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
223 key_size = sizeof(struct bpf_cgroup_storage_key);
224 value_size = sizeof(__u64);
225 max_entries = 0;
226 break;
227 case BPF_MAP_TYPE_QUEUE:
228 case BPF_MAP_TYPE_STACK:
229 key_size = 0;
230 break;
231 case BPF_MAP_TYPE_SK_STORAGE:
232 btf_key_type_id = 1;
233 btf_value_type_id = 3;
234 value_size = 8;
235 max_entries = 0;
236 map_flags = BPF_F_NO_PREALLOC;
237 btf_fd = load_sk_storage_btf();
238 if (btf_fd < 0)
239 return false;
240 break;
241 case BPF_MAP_TYPE_RINGBUF:
242 key_size = 0;
243 value_size = 0;
244 max_entries = 4096;
245 break;
246 case BPF_MAP_TYPE_UNSPEC:
247 case BPF_MAP_TYPE_HASH:
248 case BPF_MAP_TYPE_ARRAY:
249 case BPF_MAP_TYPE_PROG_ARRAY:
250 case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
251 case BPF_MAP_TYPE_PERCPU_HASH:
252 case BPF_MAP_TYPE_PERCPU_ARRAY:
253 case BPF_MAP_TYPE_CGROUP_ARRAY:
254 case BPF_MAP_TYPE_LRU_HASH:
255 case BPF_MAP_TYPE_LRU_PERCPU_HASH:
256 case BPF_MAP_TYPE_ARRAY_OF_MAPS:
257 case BPF_MAP_TYPE_HASH_OF_MAPS:
258 case BPF_MAP_TYPE_DEVMAP:
259 case BPF_MAP_TYPE_DEVMAP_HASH:
260 case BPF_MAP_TYPE_SOCKMAP:
261 case BPF_MAP_TYPE_CPUMAP:
262 case BPF_MAP_TYPE_XSKMAP:
263 case BPF_MAP_TYPE_SOCKHASH:
264 case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
265 case BPF_MAP_TYPE_STRUCT_OPS:
266 default:
267 break;
268 }
269
270 if (map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
271 map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
272 /* TODO: probe for device, once libbpf has a function to create
273 * map-in-map for offload
274 */
275 if (ifindex)
276 return false;
277
278 fd_inner = bpf_create_map(BPF_MAP_TYPE_HASH,
279 sizeof(__u32), sizeof(__u32), 1, 0);
280 if (fd_inner < 0)
281 return false;
282 fd = bpf_create_map_in_map(map_type, NULL, sizeof(__u32),
283 fd_inner, 1, 0);
284 close(fd_inner);
285 } else {
286 /* Note: No other restriction on map type probes for offload */
287 attr.map_type = map_type;
288 attr.key_size = key_size;
289 attr.value_size = value_size;
290 attr.max_entries = max_entries;
291 attr.map_flags = map_flags;
292 attr.map_ifindex = ifindex;
293 if (btf_fd >= 0) {
294 attr.btf_fd = btf_fd;
295 attr.btf_key_type_id = btf_key_type_id;
296 attr.btf_value_type_id = btf_value_type_id;
297 }
298
299 fd = bpf_create_map_xattr(&attr);
300 }
301 if (fd >= 0)
302 close(fd);
303 if (btf_fd >= 0)
304 close(btf_fd);
305
306 return fd >= 0;
307}
308
309bool bpf_probe_helper(enum bpf_func_id id, enum bpf_prog_type prog_type,
310 __u32 ifindex)
311{
312 struct bpf_insn insns[2] = {
313 BPF_EMIT_CALL(id),
314 BPF_EXIT_INSN()
315 };
316 char buf[4096] = {};
317 bool res;
318
319 probe_load(prog_type, insns, ARRAY_SIZE(insns), buf, sizeof(buf),
320 ifindex);
321 res = !grep(buf, "invalid func ") && !grep(buf, "unknown func ");
322
323 if (ifindex) {
324 switch (get_vendor_id(ifindex)) {
325 case 0x19ee: /* Netronome specific */
326 res = res && !grep(buf, "not supported by FW") &&
327 !grep(buf, "unsupported function id");
328 break;
329 default:
330 break;
331 }
332 }
333
334 return res;
335}
336
337/*
338 * Probe for availability of kernel commit (5.3):
339 *
340 * c04c0d2b968a ("bpf: increase complexity limit and maximum program size")
341 */
342bool bpf_probe_large_insn_limit(__u32 ifindex)
343{
344 struct bpf_insn insns[BPF_MAXINSNS + 1];
345 int i;
346
347 for (i = 0; i < BPF_MAXINSNS; i++)
348 insns[i] = BPF_MOV64_IMM(BPF_REG_0, 1);
349 insns[BPF_MAXINSNS] = BPF_EXIT_INSN();
350
351 errno = 0;
352 probe_load(BPF_PROG_TYPE_SCHED_CLS, insns, ARRAY_SIZE(insns), NULL, 0,
353 ifindex);
354
355 return errno != E2BIG && errno != EINVAL;
356}