xref: /linux/tools/testing/selftests/bpf/prog_tests/flow_dissector.c (revision 90d32e92011eaae8e70a9169b4e7acf4ca8f9d3a)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <test_progs.h>
3 #include <network_helpers.h>
4 #include <error.h>
5 #include <linux/if_tun.h>
6 #include <sys/uio.h>
7 
8 #include "bpf_flow.skel.h"
9 
10 #define FLOW_CONTINUE_SADDR 0x7f00007f /* 127.0.0.127 */
11 
12 #ifndef IP_MF
13 #define IP_MF 0x2000
14 #endif
15 
16 #define CHECK_FLOW_KEYS(desc, got, expected)				\
17 	_CHECK(memcmp(&got, &expected, sizeof(got)) != 0,		\
18 	      desc,							\
19 	      topts.duration,						\
20 	      "nhoff=%u/%u "						\
21 	      "thoff=%u/%u "						\
22 	      "addr_proto=0x%x/0x%x "					\
23 	      "is_frag=%u/%u "						\
24 	      "is_first_frag=%u/%u "					\
25 	      "is_encap=%u/%u "						\
26 	      "ip_proto=0x%x/0x%x "					\
27 	      "n_proto=0x%x/0x%x "					\
28 	      "flow_label=0x%x/0x%x "					\
29 	      "sport=%u/%u "						\
30 	      "dport=%u/%u\n",						\
31 	      got.nhoff, expected.nhoff,				\
32 	      got.thoff, expected.thoff,				\
33 	      got.addr_proto, expected.addr_proto,			\
34 	      got.is_frag, expected.is_frag,				\
35 	      got.is_first_frag, expected.is_first_frag,		\
36 	      got.is_encap, expected.is_encap,				\
37 	      got.ip_proto, expected.ip_proto,				\
38 	      got.n_proto, expected.n_proto,				\
39 	      got.flow_label, expected.flow_label,			\
40 	      got.sport, expected.sport,				\
41 	      got.dport, expected.dport)
42 
43 struct ipv4_pkt {
44 	struct ethhdr eth;
45 	struct iphdr iph;
46 	struct tcphdr tcp;
47 } __packed;
48 
49 struct ipip_pkt {
50 	struct ethhdr eth;
51 	struct iphdr iph;
52 	struct iphdr iph_inner;
53 	struct tcphdr tcp;
54 } __packed;
55 
56 struct svlan_ipv4_pkt {
57 	struct ethhdr eth;
58 	__u16 vlan_tci;
59 	__u16 vlan_proto;
60 	struct iphdr iph;
61 	struct tcphdr tcp;
62 } __packed;
63 
64 struct ipv6_pkt {
65 	struct ethhdr eth;
66 	struct ipv6hdr iph;
67 	struct tcphdr tcp;
68 } __packed;
69 
70 struct ipv6_frag_pkt {
71 	struct ethhdr eth;
72 	struct ipv6hdr iph;
73 	struct frag_hdr {
74 		__u8 nexthdr;
75 		__u8 reserved;
76 		__be16 frag_off;
77 		__be32 identification;
78 	} ipf;
79 	struct tcphdr tcp;
80 } __packed;
81 
82 struct dvlan_ipv6_pkt {
83 	struct ethhdr eth;
84 	__u16 vlan_tci;
85 	__u16 vlan_proto;
86 	__u16 vlan_tci2;
87 	__u16 vlan_proto2;
88 	struct ipv6hdr iph;
89 	struct tcphdr tcp;
90 } __packed;
91 
92 struct test {
93 	const char *name;
94 	union {
95 		struct ipv4_pkt ipv4;
96 		struct svlan_ipv4_pkt svlan_ipv4;
97 		struct ipip_pkt ipip;
98 		struct ipv6_pkt ipv6;
99 		struct ipv6_frag_pkt ipv6_frag;
100 		struct dvlan_ipv6_pkt dvlan_ipv6;
101 	} pkt;
102 	struct bpf_flow_keys keys;
103 	__u32 flags;
104 	__u32 retval;
105 };
106 
107 #define VLAN_HLEN	4
108 
109 static __u32 duration;
110 struct test tests[] = {
111 	{
112 		.name = "ipv4",
113 		.pkt.ipv4 = {
114 			.eth.h_proto = __bpf_constant_htons(ETH_P_IP),
115 			.iph.ihl = 5,
116 			.iph.protocol = IPPROTO_TCP,
117 			.iph.tot_len = __bpf_constant_htons(MAGIC_BYTES),
118 			.tcp.doff = 5,
119 			.tcp.source = 80,
120 			.tcp.dest = 8080,
121 		},
122 		.keys = {
123 			.nhoff = ETH_HLEN,
124 			.thoff = ETH_HLEN + sizeof(struct iphdr),
125 			.addr_proto = ETH_P_IP,
126 			.ip_proto = IPPROTO_TCP,
127 			.n_proto = __bpf_constant_htons(ETH_P_IP),
128 			.sport = 80,
129 			.dport = 8080,
130 		},
131 		.retval = BPF_OK,
132 	},
133 	{
134 		.name = "ipv6",
135 		.pkt.ipv6 = {
136 			.eth.h_proto = __bpf_constant_htons(ETH_P_IPV6),
137 			.iph.nexthdr = IPPROTO_TCP,
138 			.iph.payload_len = __bpf_constant_htons(MAGIC_BYTES),
139 			.tcp.doff = 5,
140 			.tcp.source = 80,
141 			.tcp.dest = 8080,
142 		},
143 		.keys = {
144 			.nhoff = ETH_HLEN,
145 			.thoff = ETH_HLEN + sizeof(struct ipv6hdr),
146 			.addr_proto = ETH_P_IPV6,
147 			.ip_proto = IPPROTO_TCP,
148 			.n_proto = __bpf_constant_htons(ETH_P_IPV6),
149 			.sport = 80,
150 			.dport = 8080,
151 		},
152 		.retval = BPF_OK,
153 	},
154 	{
155 		.name = "802.1q-ipv4",
156 		.pkt.svlan_ipv4 = {
157 			.eth.h_proto = __bpf_constant_htons(ETH_P_8021Q),
158 			.vlan_proto = __bpf_constant_htons(ETH_P_IP),
159 			.iph.ihl = 5,
160 			.iph.protocol = IPPROTO_TCP,
161 			.iph.tot_len = __bpf_constant_htons(MAGIC_BYTES),
162 			.tcp.doff = 5,
163 			.tcp.source = 80,
164 			.tcp.dest = 8080,
165 		},
166 		.keys = {
167 			.nhoff = ETH_HLEN + VLAN_HLEN,
168 			.thoff = ETH_HLEN + VLAN_HLEN + sizeof(struct iphdr),
169 			.addr_proto = ETH_P_IP,
170 			.ip_proto = IPPROTO_TCP,
171 			.n_proto = __bpf_constant_htons(ETH_P_IP),
172 			.sport = 80,
173 			.dport = 8080,
174 		},
175 		.retval = BPF_OK,
176 	},
177 	{
178 		.name = "802.1ad-ipv6",
179 		.pkt.dvlan_ipv6 = {
180 			.eth.h_proto = __bpf_constant_htons(ETH_P_8021AD),
181 			.vlan_proto = __bpf_constant_htons(ETH_P_8021Q),
182 			.vlan_proto2 = __bpf_constant_htons(ETH_P_IPV6),
183 			.iph.nexthdr = IPPROTO_TCP,
184 			.iph.payload_len = __bpf_constant_htons(MAGIC_BYTES),
185 			.tcp.doff = 5,
186 			.tcp.source = 80,
187 			.tcp.dest = 8080,
188 		},
189 		.keys = {
190 			.nhoff = ETH_HLEN + VLAN_HLEN * 2,
191 			.thoff = ETH_HLEN + VLAN_HLEN * 2 +
192 				sizeof(struct ipv6hdr),
193 			.addr_proto = ETH_P_IPV6,
194 			.ip_proto = IPPROTO_TCP,
195 			.n_proto = __bpf_constant_htons(ETH_P_IPV6),
196 			.sport = 80,
197 			.dport = 8080,
198 		},
199 		.retval = BPF_OK,
200 	},
201 	{
202 		.name = "ipv4-frag",
203 		.pkt.ipv4 = {
204 			.eth.h_proto = __bpf_constant_htons(ETH_P_IP),
205 			.iph.ihl = 5,
206 			.iph.protocol = IPPROTO_TCP,
207 			.iph.tot_len = __bpf_constant_htons(MAGIC_BYTES),
208 			.iph.frag_off = __bpf_constant_htons(IP_MF),
209 			.tcp.doff = 5,
210 			.tcp.source = 80,
211 			.tcp.dest = 8080,
212 		},
213 		.keys = {
214 			.flags = BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG,
215 			.nhoff = ETH_HLEN,
216 			.thoff = ETH_HLEN + sizeof(struct iphdr),
217 			.addr_proto = ETH_P_IP,
218 			.ip_proto = IPPROTO_TCP,
219 			.n_proto = __bpf_constant_htons(ETH_P_IP),
220 			.is_frag = true,
221 			.is_first_frag = true,
222 			.sport = 80,
223 			.dport = 8080,
224 		},
225 		.flags = BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG,
226 		.retval = BPF_OK,
227 	},
228 	{
229 		.name = "ipv4-no-frag",
230 		.pkt.ipv4 = {
231 			.eth.h_proto = __bpf_constant_htons(ETH_P_IP),
232 			.iph.ihl = 5,
233 			.iph.protocol = IPPROTO_TCP,
234 			.iph.tot_len = __bpf_constant_htons(MAGIC_BYTES),
235 			.iph.frag_off = __bpf_constant_htons(IP_MF),
236 			.tcp.doff = 5,
237 			.tcp.source = 80,
238 			.tcp.dest = 8080,
239 		},
240 		.keys = {
241 			.nhoff = ETH_HLEN,
242 			.thoff = ETH_HLEN + sizeof(struct iphdr),
243 			.addr_proto = ETH_P_IP,
244 			.ip_proto = IPPROTO_TCP,
245 			.n_proto = __bpf_constant_htons(ETH_P_IP),
246 			.is_frag = true,
247 			.is_first_frag = true,
248 		},
249 		.retval = BPF_OK,
250 	},
251 	{
252 		.name = "ipv6-frag",
253 		.pkt.ipv6_frag = {
254 			.eth.h_proto = __bpf_constant_htons(ETH_P_IPV6),
255 			.iph.nexthdr = IPPROTO_FRAGMENT,
256 			.iph.payload_len = __bpf_constant_htons(MAGIC_BYTES),
257 			.ipf.nexthdr = IPPROTO_TCP,
258 			.tcp.doff = 5,
259 			.tcp.source = 80,
260 			.tcp.dest = 8080,
261 		},
262 		.keys = {
263 			.flags = BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG,
264 			.nhoff = ETH_HLEN,
265 			.thoff = ETH_HLEN + sizeof(struct ipv6hdr) +
266 				sizeof(struct frag_hdr),
267 			.addr_proto = ETH_P_IPV6,
268 			.ip_proto = IPPROTO_TCP,
269 			.n_proto = __bpf_constant_htons(ETH_P_IPV6),
270 			.is_frag = true,
271 			.is_first_frag = true,
272 			.sport = 80,
273 			.dport = 8080,
274 		},
275 		.flags = BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG,
276 		.retval = BPF_OK,
277 	},
278 	{
279 		.name = "ipv6-no-frag",
280 		.pkt.ipv6_frag = {
281 			.eth.h_proto = __bpf_constant_htons(ETH_P_IPV6),
282 			.iph.nexthdr = IPPROTO_FRAGMENT,
283 			.iph.payload_len = __bpf_constant_htons(MAGIC_BYTES),
284 			.ipf.nexthdr = IPPROTO_TCP,
285 			.tcp.doff = 5,
286 			.tcp.source = 80,
287 			.tcp.dest = 8080,
288 		},
289 		.keys = {
290 			.nhoff = ETH_HLEN,
291 			.thoff = ETH_HLEN + sizeof(struct ipv6hdr) +
292 				sizeof(struct frag_hdr),
293 			.addr_proto = ETH_P_IPV6,
294 			.ip_proto = IPPROTO_TCP,
295 			.n_proto = __bpf_constant_htons(ETH_P_IPV6),
296 			.is_frag = true,
297 			.is_first_frag = true,
298 		},
299 		.retval = BPF_OK,
300 	},
301 	{
302 		.name = "ipv6-flow-label",
303 		.pkt.ipv6 = {
304 			.eth.h_proto = __bpf_constant_htons(ETH_P_IPV6),
305 			.iph.nexthdr = IPPROTO_TCP,
306 			.iph.payload_len = __bpf_constant_htons(MAGIC_BYTES),
307 			.iph.flow_lbl = { 0xb, 0xee, 0xef },
308 			.tcp.doff = 5,
309 			.tcp.source = 80,
310 			.tcp.dest = 8080,
311 		},
312 		.keys = {
313 			.nhoff = ETH_HLEN,
314 			.thoff = ETH_HLEN + sizeof(struct ipv6hdr),
315 			.addr_proto = ETH_P_IPV6,
316 			.ip_proto = IPPROTO_TCP,
317 			.n_proto = __bpf_constant_htons(ETH_P_IPV6),
318 			.sport = 80,
319 			.dport = 8080,
320 			.flow_label = __bpf_constant_htonl(0xbeeef),
321 		},
322 		.retval = BPF_OK,
323 	},
324 	{
325 		.name = "ipv6-no-flow-label",
326 		.pkt.ipv6 = {
327 			.eth.h_proto = __bpf_constant_htons(ETH_P_IPV6),
328 			.iph.nexthdr = IPPROTO_TCP,
329 			.iph.payload_len = __bpf_constant_htons(MAGIC_BYTES),
330 			.iph.flow_lbl = { 0xb, 0xee, 0xef },
331 			.tcp.doff = 5,
332 			.tcp.source = 80,
333 			.tcp.dest = 8080,
334 		},
335 		.keys = {
336 			.flags = BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL,
337 			.nhoff = ETH_HLEN,
338 			.thoff = ETH_HLEN + sizeof(struct ipv6hdr),
339 			.addr_proto = ETH_P_IPV6,
340 			.ip_proto = IPPROTO_TCP,
341 			.n_proto = __bpf_constant_htons(ETH_P_IPV6),
342 			.flow_label = __bpf_constant_htonl(0xbeeef),
343 		},
344 		.flags = BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL,
345 		.retval = BPF_OK,
346 	},
347 	{
348 		.name = "ipv6-empty-flow-label",
349 		.pkt.ipv6 = {
350 			.eth.h_proto = __bpf_constant_htons(ETH_P_IPV6),
351 			.iph.nexthdr = IPPROTO_TCP,
352 			.iph.payload_len = __bpf_constant_htons(MAGIC_BYTES),
353 			.iph.flow_lbl = { 0x00, 0x00, 0x00 },
354 			.tcp.doff = 5,
355 			.tcp.source = 80,
356 			.tcp.dest = 8080,
357 		},
358 		.keys = {
359 			.flags = BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL,
360 			.nhoff = ETH_HLEN,
361 			.thoff = ETH_HLEN + sizeof(struct ipv6hdr),
362 			.addr_proto = ETH_P_IPV6,
363 			.ip_proto = IPPROTO_TCP,
364 			.n_proto = __bpf_constant_htons(ETH_P_IPV6),
365 			.sport = 80,
366 			.dport = 8080,
367 		},
368 		.flags = BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL,
369 		.retval = BPF_OK,
370 	},
371 	{
372 		.name = "ipip-encap",
373 		.pkt.ipip = {
374 			.eth.h_proto = __bpf_constant_htons(ETH_P_IP),
375 			.iph.ihl = 5,
376 			.iph.protocol = IPPROTO_IPIP,
377 			.iph.tot_len = __bpf_constant_htons(MAGIC_BYTES),
378 			.iph_inner.ihl = 5,
379 			.iph_inner.protocol = IPPROTO_TCP,
380 			.iph_inner.tot_len =
381 				__bpf_constant_htons(MAGIC_BYTES) -
382 				sizeof(struct iphdr),
383 			.tcp.doff = 5,
384 			.tcp.source = 80,
385 			.tcp.dest = 8080,
386 		},
387 		.keys = {
388 			.nhoff = ETH_HLEN,
389 			.thoff = ETH_HLEN + sizeof(struct iphdr) +
390 				sizeof(struct iphdr),
391 			.addr_proto = ETH_P_IP,
392 			.ip_proto = IPPROTO_TCP,
393 			.n_proto = __bpf_constant_htons(ETH_P_IP),
394 			.is_encap = true,
395 			.sport = 80,
396 			.dport = 8080,
397 		},
398 		.retval = BPF_OK,
399 	},
400 	{
401 		.name = "ipip-no-encap",
402 		.pkt.ipip = {
403 			.eth.h_proto = __bpf_constant_htons(ETH_P_IP),
404 			.iph.ihl = 5,
405 			.iph.protocol = IPPROTO_IPIP,
406 			.iph.tot_len = __bpf_constant_htons(MAGIC_BYTES),
407 			.iph_inner.ihl = 5,
408 			.iph_inner.protocol = IPPROTO_TCP,
409 			.iph_inner.tot_len =
410 				__bpf_constant_htons(MAGIC_BYTES) -
411 				sizeof(struct iphdr),
412 			.tcp.doff = 5,
413 			.tcp.source = 80,
414 			.tcp.dest = 8080,
415 		},
416 		.keys = {
417 			.flags = BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP,
418 			.nhoff = ETH_HLEN,
419 			.thoff = ETH_HLEN + sizeof(struct iphdr),
420 			.addr_proto = ETH_P_IP,
421 			.ip_proto = IPPROTO_IPIP,
422 			.n_proto = __bpf_constant_htons(ETH_P_IP),
423 			.is_encap = true,
424 		},
425 		.flags = BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP,
426 		.retval = BPF_OK,
427 	},
428 	{
429 		.name = "ipip-encap-dissector-continue",
430 		.pkt.ipip = {
431 			.eth.h_proto = __bpf_constant_htons(ETH_P_IP),
432 			.iph.ihl = 5,
433 			.iph.protocol = IPPROTO_IPIP,
434 			.iph.tot_len = __bpf_constant_htons(MAGIC_BYTES),
435 			.iph.saddr = __bpf_constant_htonl(FLOW_CONTINUE_SADDR),
436 			.iph_inner.ihl = 5,
437 			.iph_inner.protocol = IPPROTO_TCP,
438 			.iph_inner.tot_len =
439 				__bpf_constant_htons(MAGIC_BYTES) -
440 				sizeof(struct iphdr),
441 			.tcp.doff = 5,
442 			.tcp.source = 99,
443 			.tcp.dest = 9090,
444 		},
445 		.retval = BPF_FLOW_DISSECTOR_CONTINUE,
446 	},
447 };
448 
449 static int create_tap(const char *ifname)
450 {
451 	struct ifreq ifr = {
452 		.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_NAPI | IFF_NAPI_FRAGS,
453 	};
454 	int fd, ret;
455 
456 	strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
457 
458 	fd = open("/dev/net/tun", O_RDWR);
459 	if (fd < 0)
460 		return -1;
461 
462 	ret = ioctl(fd, TUNSETIFF, &ifr);
463 	if (ret)
464 		return -1;
465 
466 	return fd;
467 }
468 
469 static int tx_tap(int fd, void *pkt, size_t len)
470 {
471 	struct iovec iov[] = {
472 		{
473 			.iov_len = len,
474 			.iov_base = pkt,
475 		},
476 	};
477 	return writev(fd, iov, ARRAY_SIZE(iov));
478 }
479 
480 static int ifup(const char *ifname)
481 {
482 	struct ifreq ifr = {};
483 	int sk, ret;
484 
485 	strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
486 
487 	sk = socket(PF_INET, SOCK_DGRAM, 0);
488 	if (sk < 0)
489 		return -1;
490 
491 	ret = ioctl(sk, SIOCGIFFLAGS, &ifr);
492 	if (ret) {
493 		close(sk);
494 		return -1;
495 	}
496 
497 	ifr.ifr_flags |= IFF_UP;
498 	ret = ioctl(sk, SIOCSIFFLAGS, &ifr);
499 	if (ret) {
500 		close(sk);
501 		return -1;
502 	}
503 
504 	close(sk);
505 	return 0;
506 }
507 
508 static int init_prog_array(struct bpf_object *obj, struct bpf_map *prog_array)
509 {
510 	int i, err, map_fd, prog_fd;
511 	struct bpf_program *prog;
512 	char prog_name[32];
513 
514 	map_fd = bpf_map__fd(prog_array);
515 	if (map_fd < 0)
516 		return -1;
517 
518 	for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
519 		snprintf(prog_name, sizeof(prog_name), "flow_dissector_%d", i);
520 
521 		prog = bpf_object__find_program_by_name(obj, prog_name);
522 		if (!prog)
523 			return -1;
524 
525 		prog_fd = bpf_program__fd(prog);
526 		if (prog_fd < 0)
527 			return -1;
528 
529 		err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
530 		if (err)
531 			return -1;
532 	}
533 	return 0;
534 }
535 
536 static void run_tests_skb_less(int tap_fd, struct bpf_map *keys)
537 {
538 	int i, err, keys_fd;
539 
540 	keys_fd = bpf_map__fd(keys);
541 	if (CHECK(keys_fd < 0, "bpf_map__fd", "err %d\n", keys_fd))
542 		return;
543 
544 	for (i = 0; i < ARRAY_SIZE(tests); i++) {
545 		/* Keep in sync with 'flags' from eth_get_headlen. */
546 		__u32 eth_get_headlen_flags =
547 			BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG;
548 		LIBBPF_OPTS(bpf_test_run_opts, topts);
549 		struct bpf_flow_keys flow_keys = {};
550 		__u32 key = (__u32)(tests[i].keys.sport) << 16 |
551 			    tests[i].keys.dport;
552 
553 		/* For skb-less case we can't pass input flags; run
554 		 * only the tests that have a matching set of flags.
555 		 */
556 
557 		if (tests[i].flags != eth_get_headlen_flags)
558 			continue;
559 
560 		err = tx_tap(tap_fd, &tests[i].pkt, sizeof(tests[i].pkt));
561 		CHECK(err < 0, "tx_tap", "err %d errno %d\n", err, errno);
562 
563 		/* check the stored flow_keys only if BPF_OK expected */
564 		if (tests[i].retval != BPF_OK)
565 			continue;
566 
567 		err = bpf_map_lookup_elem(keys_fd, &key, &flow_keys);
568 		ASSERT_OK(err, "bpf_map_lookup_elem");
569 
570 		CHECK_FLOW_KEYS(tests[i].name, flow_keys, tests[i].keys);
571 
572 		err = bpf_map_delete_elem(keys_fd, &key);
573 		ASSERT_OK(err, "bpf_map_delete_elem");
574 	}
575 }
576 
577 static void test_skb_less_prog_attach(struct bpf_flow *skel, int tap_fd)
578 {
579 	int err, prog_fd;
580 
581 	prog_fd = bpf_program__fd(skel->progs._dissect);
582 	if (CHECK(prog_fd < 0, "bpf_program__fd", "err %d\n", prog_fd))
583 		return;
584 
585 	err = bpf_prog_attach(prog_fd, 0, BPF_FLOW_DISSECTOR, 0);
586 	if (CHECK(err, "bpf_prog_attach", "err %d errno %d\n", err, errno))
587 		return;
588 
589 	run_tests_skb_less(tap_fd, skel->maps.last_dissection);
590 
591 	err = bpf_prog_detach2(prog_fd, 0, BPF_FLOW_DISSECTOR);
592 	CHECK(err, "bpf_prog_detach2", "err %d errno %d\n", err, errno);
593 }
594 
595 static void test_skb_less_link_create(struct bpf_flow *skel, int tap_fd)
596 {
597 	struct bpf_link *link;
598 	int err, net_fd;
599 
600 	net_fd = open("/proc/self/ns/net", O_RDONLY);
601 	if (CHECK(net_fd < 0, "open(/proc/self/ns/net)", "err %d\n", errno))
602 		return;
603 
604 	link = bpf_program__attach_netns(skel->progs._dissect, net_fd);
605 	if (!ASSERT_OK_PTR(link, "attach_netns"))
606 		goto out_close;
607 
608 	run_tests_skb_less(tap_fd, skel->maps.last_dissection);
609 
610 	err = bpf_link__destroy(link);
611 	CHECK(err, "bpf_link__destroy", "err %d\n", err);
612 out_close:
613 	close(net_fd);
614 }
615 
616 void test_flow_dissector(void)
617 {
618 	int i, err, prog_fd, keys_fd = -1, tap_fd;
619 	struct bpf_flow *skel;
620 
621 	skel = bpf_flow__open_and_load();
622 	if (CHECK(!skel, "skel", "failed to open/load skeleton\n"))
623 		return;
624 
625 	prog_fd = bpf_program__fd(skel->progs._dissect);
626 	if (CHECK(prog_fd < 0, "bpf_program__fd", "err %d\n", prog_fd))
627 		goto out_destroy_skel;
628 	keys_fd = bpf_map__fd(skel->maps.last_dissection);
629 	if (CHECK(keys_fd < 0, "bpf_map__fd", "err %d\n", keys_fd))
630 		goto out_destroy_skel;
631 	err = init_prog_array(skel->obj, skel->maps.jmp_table);
632 	if (CHECK(err, "init_prog_array", "err %d\n", err))
633 		goto out_destroy_skel;
634 
635 	for (i = 0; i < ARRAY_SIZE(tests); i++) {
636 		struct bpf_flow_keys flow_keys;
637 		LIBBPF_OPTS(bpf_test_run_opts, topts,
638 			.data_in = &tests[i].pkt,
639 			.data_size_in = sizeof(tests[i].pkt),
640 			.data_out = &flow_keys,
641 		);
642 		static struct bpf_flow_keys ctx = {};
643 
644 		if (tests[i].flags) {
645 			topts.ctx_in = &ctx;
646 			topts.ctx_size_in = sizeof(ctx);
647 			ctx.flags = tests[i].flags;
648 		}
649 
650 		err = bpf_prog_test_run_opts(prog_fd, &topts);
651 		ASSERT_OK(err, "test_run");
652 		ASSERT_EQ(topts.retval, tests[i].retval, "test_run retval");
653 
654 		/* check the resulting flow_keys only if BPF_OK returned */
655 		if (topts.retval != BPF_OK)
656 			continue;
657 		ASSERT_EQ(topts.data_size_out, sizeof(flow_keys),
658 			  "test_run data_size_out");
659 		CHECK_FLOW_KEYS(tests[i].name, flow_keys, tests[i].keys);
660 	}
661 
662 	/* Do the same tests but for skb-less flow dissector.
663 	 * We use a known path in the net/tun driver that calls
664 	 * eth_get_headlen and we manually export bpf_flow_keys
665 	 * via BPF map in this case.
666 	 */
667 
668 	tap_fd = create_tap("tap0");
669 	CHECK(tap_fd < 0, "create_tap", "tap_fd %d errno %d\n", tap_fd, errno);
670 	err = ifup("tap0");
671 	CHECK(err, "ifup", "err %d errno %d\n", err, errno);
672 
673 	/* Test direct prog attachment */
674 	test_skb_less_prog_attach(skel, tap_fd);
675 	/* Test indirect prog attachment via link */
676 	test_skb_less_link_create(skel, tap_fd);
677 
678 	close(tap_fd);
679 out_destroy_skel:
680 	bpf_flow__destroy(skel);
681 }
682