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 | O_CLOEXEC);
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 	case BPF_MAP_TYPE_TASK_STORAGE:
236 		btf_key_type_id = 1;
237 		btf_value_type_id = 3;
238 		value_size = 8;
239 		max_entries = 0;
240 		map_flags = BPF_F_NO_PREALLOC;
241 		btf_fd = load_local_storage_btf();
242 		if (btf_fd < 0)
243 			return false;
244 		break;
245 	case BPF_MAP_TYPE_RINGBUF:
246 		key_size = 0;
247 		value_size = 0;
248 		max_entries = 4096;
249 		break;
250 	case BPF_MAP_TYPE_UNSPEC:
251 	case BPF_MAP_TYPE_HASH:
252 	case BPF_MAP_TYPE_ARRAY:
253 	case BPF_MAP_TYPE_PROG_ARRAY:
254 	case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
255 	case BPF_MAP_TYPE_PERCPU_HASH:
256 	case BPF_MAP_TYPE_PERCPU_ARRAY:
257 	case BPF_MAP_TYPE_CGROUP_ARRAY:
258 	case BPF_MAP_TYPE_LRU_HASH:
259 	case BPF_MAP_TYPE_LRU_PERCPU_HASH:
260 	case BPF_MAP_TYPE_ARRAY_OF_MAPS:
261 	case BPF_MAP_TYPE_HASH_OF_MAPS:
262 	case BPF_MAP_TYPE_DEVMAP:
263 	case BPF_MAP_TYPE_DEVMAP_HASH:
264 	case BPF_MAP_TYPE_SOCKMAP:
265 	case BPF_MAP_TYPE_CPUMAP:
266 	case BPF_MAP_TYPE_XSKMAP:
267 	case BPF_MAP_TYPE_SOCKHASH:
268 	case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
269 	case BPF_MAP_TYPE_STRUCT_OPS:
270 	default:
271 		break;
272 	}
273 
274 	if (map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
275 	    map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
276 		/* TODO: probe for device, once libbpf has a function to create
277 		 * map-in-map for offload
278 		 */
279 		if (ifindex)
280 			return false;
281 
282 		fd_inner = bpf_create_map(BPF_MAP_TYPE_HASH,
283 					  sizeof(__u32), sizeof(__u32), 1, 0);
284 		if (fd_inner < 0)
285 			return false;
286 		fd = bpf_create_map_in_map(map_type, NULL, sizeof(__u32),
287 					   fd_inner, 1, 0);
288 		close(fd_inner);
289 	} else {
290 		/* Note: No other restriction on map type probes for offload */
291 		attr.map_type = map_type;
292 		attr.key_size = key_size;
293 		attr.value_size = value_size;
294 		attr.max_entries = max_entries;
295 		attr.map_flags = map_flags;
296 		attr.map_ifindex = ifindex;
297 		if (btf_fd >= 0) {
298 			attr.btf_fd = btf_fd;
299 			attr.btf_key_type_id = btf_key_type_id;
300 			attr.btf_value_type_id = btf_value_type_id;
301 		}
302 
303 		fd = bpf_create_map_xattr(&attr);
304 	}
305 	if (fd >= 0)
306 		close(fd);
307 	if (btf_fd >= 0)
308 		close(btf_fd);
309 
310 	return fd >= 0;
311 }
312 
bpf_probe_helper(enum bpf_func_id id,enum bpf_prog_type prog_type,__u32 ifindex)313 bool bpf_probe_helper(enum bpf_func_id id, enum bpf_prog_type prog_type,
314 		      __u32 ifindex)
315 {
316 	struct bpf_insn insns[2] = {
317 		BPF_EMIT_CALL(id),
318 		BPF_EXIT_INSN()
319 	};
320 	char buf[4096] = {};
321 	bool res;
322 
323 	probe_load(prog_type, insns, ARRAY_SIZE(insns), buf, sizeof(buf),
324 		   ifindex);
325 	res = !grep(buf, "invalid func ") && !grep(buf, "unknown func ");
326 
327 	if (ifindex) {
328 		switch (get_vendor_id(ifindex)) {
329 		case 0x19ee: /* Netronome specific */
330 			res = res && !grep(buf, "not supported by FW") &&
331 				!grep(buf, "unsupported function id");
332 			break;
333 		default:
334 			break;
335 		}
336 	}
337 
338 	return res;
339 }
340 
341 /*
342  * Probe for availability of kernel commit (5.3):
343  *
344  * c04c0d2b968a ("bpf: increase complexity limit and maximum program size")
345  */
bpf_probe_large_insn_limit(__u32 ifindex)346 bool bpf_probe_large_insn_limit(__u32 ifindex)
347 {
348 	struct bpf_insn insns[BPF_MAXINSNS + 1];
349 	int i;
350 
351 	for (i = 0; i < BPF_MAXINSNS; i++)
352 		insns[i] = BPF_MOV64_IMM(BPF_REG_0, 1);
353 	insns[BPF_MAXINSNS] = BPF_EXIT_INSN();
354 
355 	errno = 0;
356 	probe_load(BPF_PROG_TYPE_SCHED_CLS, insns, ARRAY_SIZE(insns), NULL, 0,
357 		   ifindex);
358 
359 	return errno != E2BIG && errno != EINVAL;
360 }
361