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_KPROBE:
 79		xattr.kern_version = get_kernel_version();
 80		break;
 81	case BPF_PROG_TYPE_UNSPEC:
 82	case BPF_PROG_TYPE_SOCKET_FILTER:
 83	case BPF_PROG_TYPE_SCHED_CLS:
 84	case BPF_PROG_TYPE_SCHED_ACT:
 85	case BPF_PROG_TYPE_TRACEPOINT:
 86	case BPF_PROG_TYPE_XDP:
 87	case BPF_PROG_TYPE_PERF_EVENT:
 88	case BPF_PROG_TYPE_CGROUP_SKB:
 89	case BPF_PROG_TYPE_CGROUP_SOCK:
 90	case BPF_PROG_TYPE_LWT_IN:
 91	case BPF_PROG_TYPE_LWT_OUT:
 92	case BPF_PROG_TYPE_LWT_XMIT:
 93	case BPF_PROG_TYPE_SOCK_OPS:
 94	case BPF_PROG_TYPE_SK_SKB:
 95	case BPF_PROG_TYPE_CGROUP_DEVICE:
 96	case BPF_PROG_TYPE_SK_MSG:
 97	case BPF_PROG_TYPE_RAW_TRACEPOINT:
 98	case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
 99	case BPF_PROG_TYPE_LWT_SEG6LOCAL:
100	case BPF_PROG_TYPE_LIRC_MODE2:
101	case BPF_PROG_TYPE_SK_REUSEPORT:
102	case BPF_PROG_TYPE_FLOW_DISSECTOR:
103	case BPF_PROG_TYPE_CGROUP_SYSCTL:
104	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
105	default:
106		break;
107	}
108
109	xattr.prog_type = prog_type;
110	xattr.insns = insns;
111	xattr.insns_cnt = insns_cnt;
112	xattr.license = "GPL";
113	xattr.prog_ifindex = ifindex;
114
115	fd = bpf_load_program_xattr(&xattr, buf, buf_len);
116	if (fd >= 0)
117		close(fd);
118}
119
120bool bpf_probe_prog_type(enum bpf_prog_type prog_type, __u32 ifindex)
121{
122	struct bpf_insn insns[2] = {
123		BPF_MOV64_IMM(BPF_REG_0, 0),
124		BPF_EXIT_INSN()
125	};
126
127	if (ifindex && prog_type == BPF_PROG_TYPE_SCHED_CLS)
128		/* nfp returns -EINVAL on exit(0) with TC offload */
129		insns[0].imm = 2;
130
131	errno = 0;
132	probe_load(prog_type, insns, ARRAY_SIZE(insns), NULL, 0, ifindex);
133
134	return errno != EINVAL && errno != EOPNOTSUPP;
135}
136
137int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
138			 const char *str_sec, size_t str_len)
139{
140	struct btf_header hdr = {
141		.magic = BTF_MAGIC,
142		.version = BTF_VERSION,
143		.hdr_len = sizeof(struct btf_header),
144		.type_len = types_len,
145		.str_off = types_len,
146		.str_len = str_len,
147	};
148	int btf_fd, btf_len;
149	__u8 *raw_btf;
150
151	btf_len = hdr.hdr_len + hdr.type_len + hdr.str_len;
152	raw_btf = malloc(btf_len);
153	if (!raw_btf)
154		return -ENOMEM;
155
156	memcpy(raw_btf, &hdr, sizeof(hdr));
157	memcpy(raw_btf + hdr.hdr_len, raw_types, hdr.type_len);
158	memcpy(raw_btf + hdr.hdr_len + hdr.type_len, str_sec, hdr.str_len);
159
160	btf_fd = bpf_load_btf(raw_btf, btf_len, NULL, 0, false);
161
162	free(raw_btf);
163	return btf_fd;
164}
165
166static int load_sk_storage_btf(void)
167{
168	const char strs[] = "\0bpf_spin_lock\0val\0cnt\0l";
169	/* struct bpf_spin_lock {
170	 *   int val;
171	 * };
172	 * struct val {
173	 *   int cnt;
174	 *   struct bpf_spin_lock l;
175	 * };
176	 */
177	__u32 types[] = {
178		/* int */
179		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
180		/* struct bpf_spin_lock */                      /* [2] */
181		BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4),
182		BTF_MEMBER_ENC(15, 1, 0), /* int val; */
183		/* struct val */                                /* [3] */
184		BTF_TYPE_ENC(15, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 2), 8),
185		BTF_MEMBER_ENC(19, 1, 0), /* int cnt; */
186		BTF_MEMBER_ENC(23, 2, 32),/* struct bpf_spin_lock l; */
187	};
188
189	return libbpf__load_raw_btf((char *)types, sizeof(types),
190				     strs, sizeof(strs));
191}
192
193bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex)
194{
195	int key_size, value_size, max_entries, map_flags;
196	__u32 btf_key_type_id = 0, btf_value_type_id = 0;
197	struct bpf_create_map_attr attr = {};
198	int fd = -1, btf_fd = -1, fd_inner;
199
200	key_size	= sizeof(__u32);
201	value_size	= sizeof(__u32);
202	max_entries	= 1;
203	map_flags	= 0;
204
205	switch (map_type) {
206	case BPF_MAP_TYPE_STACK_TRACE:
207		value_size	= sizeof(__u64);
208		break;
209	case BPF_MAP_TYPE_LPM_TRIE:
210		key_size	= sizeof(__u64);
211		value_size	= sizeof(__u64);
212		map_flags	= BPF_F_NO_PREALLOC;
213		break;
214	case BPF_MAP_TYPE_CGROUP_STORAGE:
215	case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
216		key_size	= sizeof(struct bpf_cgroup_storage_key);
217		value_size	= sizeof(__u64);
218		max_entries	= 0;
219		break;
220	case BPF_MAP_TYPE_QUEUE:
221	case BPF_MAP_TYPE_STACK:
222		key_size	= 0;
223		break;
224	case BPF_MAP_TYPE_SK_STORAGE:
225		btf_key_type_id = 1;
226		btf_value_type_id = 3;
227		value_size = 8;
228		max_entries = 0;
229		map_flags = BPF_F_NO_PREALLOC;
230		btf_fd = load_sk_storage_btf();
231		if (btf_fd < 0)
232			return false;
233		break;
234	case BPF_MAP_TYPE_UNSPEC:
235	case BPF_MAP_TYPE_HASH:
236	case BPF_MAP_TYPE_ARRAY:
237	case BPF_MAP_TYPE_PROG_ARRAY:
238	case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
239	case BPF_MAP_TYPE_PERCPU_HASH:
240	case BPF_MAP_TYPE_PERCPU_ARRAY:
241	case BPF_MAP_TYPE_CGROUP_ARRAY:
242	case BPF_MAP_TYPE_LRU_HASH:
243	case BPF_MAP_TYPE_LRU_PERCPU_HASH:
244	case BPF_MAP_TYPE_ARRAY_OF_MAPS:
245	case BPF_MAP_TYPE_HASH_OF_MAPS:
246	case BPF_MAP_TYPE_DEVMAP:
247	case BPF_MAP_TYPE_DEVMAP_HASH:
248	case BPF_MAP_TYPE_SOCKMAP:
249	case BPF_MAP_TYPE_CPUMAP:
250	case BPF_MAP_TYPE_XSKMAP:
251	case BPF_MAP_TYPE_SOCKHASH:
252	case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
253	default:
254		break;
255	}
256
257	if (map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
258	    map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
259		/* TODO: probe for device, once libbpf has a function to create
260		 * map-in-map for offload
261		 */
262		if (ifindex)
263			return false;
264
265		fd_inner = bpf_create_map(BPF_MAP_TYPE_HASH,
266					  sizeof(__u32), sizeof(__u32), 1, 0);
267		if (fd_inner < 0)
268			return false;
269		fd = bpf_create_map_in_map(map_type, NULL, sizeof(__u32),
270					   fd_inner, 1, 0);
271		close(fd_inner);
272	} else {
273		/* Note: No other restriction on map type probes for offload */
274		attr.map_type = map_type;
275		attr.key_size = key_size;
276		attr.value_size = value_size;
277		attr.max_entries = max_entries;
278		attr.map_flags = map_flags;
279		attr.map_ifindex = ifindex;
280		if (btf_fd >= 0) {
281			attr.btf_fd = btf_fd;
282			attr.btf_key_type_id = btf_key_type_id;
283			attr.btf_value_type_id = btf_value_type_id;
284		}
285
286		fd = bpf_create_map_xattr(&attr);
287	}
288	if (fd >= 0)
289		close(fd);
290	if (btf_fd >= 0)
291		close(btf_fd);
292
293	return fd >= 0;
294}
295
296bool bpf_probe_helper(enum bpf_func_id id, enum bpf_prog_type prog_type,
297		      __u32 ifindex)
298{
299	struct bpf_insn insns[2] = {
300		BPF_EMIT_CALL(id),
301		BPF_EXIT_INSN()
302	};
303	char buf[4096] = {};
304	bool res;
305
306	probe_load(prog_type, insns, ARRAY_SIZE(insns), buf, sizeof(buf),
307		   ifindex);
308	res = !grep(buf, "invalid func ") && !grep(buf, "unknown func ");
309
310	if (ifindex) {
311		switch (get_vendor_id(ifindex)) {
312		case 0x19ee: /* Netronome specific */
313			res = res && !grep(buf, "not supported by FW") &&
314				!grep(buf, "unsupported function id");
315			break;
316		default:
317			break;
318		}
319	}
320
321	return res;
322}