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
 20static bool grep(const char *buffer, const char *pattern)
 21{
 22	return !!strstr(buffer, pattern);
 23}
 24
 25static 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
 51static 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
 67static void
 68probe_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
129bool 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
146int 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
175static 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
202bool 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
313bool 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 */
346bool 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}