summaryrefslogtreecommitdiffstats
path: root/tools/testing/selftests/net/ip_defrag.c
blob: 5d56cc0838f627b44afc0ce225bdb2330fbcbe2a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
// SPDX-License-Identifier: GPL-2.0

#define _GNU_SOURCE

#include <arpa/inet.h>
#include <errno.h>
#include <error.h>
#include <linux/in.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <netinet/udp.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

static bool		cfg_do_ipv4;
static bool		cfg_do_ipv6;
static bool		cfg_verbose;
static bool		cfg_overlap;
static unsigned short	cfg_port = 9000;

const struct in_addr addr4 = { .s_addr = __constant_htonl(INADDR_LOOPBACK + 2) };
const struct in6_addr addr6 = IN6ADDR_LOOPBACK_INIT;

#define IP4_HLEN	(sizeof(struct iphdr))
#define IP6_HLEN	(sizeof(struct ip6_hdr))
#define UDP_HLEN	(sizeof(struct udphdr))

/* IPv6 fragment header lenth. */
#define FRAG_HLEN	8

static int payload_len;
static int max_frag_len;

#define MSG_LEN_MAX	60000	/* Max UDP payload length. */

#define IP4_MF		(1u << 13)  /* IPv4 MF flag. */
#define IP6_MF		(1)  /* IPv6 MF flag. */

#define CSUM_MANGLED_0 (0xffff)

static uint8_t udp_payload[MSG_LEN_MAX];
static uint8_t ip_frame[IP_MAXPACKET];
static uint32_t ip_id = 0xabcd;
static int msg_counter;
static int frag_counter;
static unsigned int seed;

/* Receive a UDP packet. Validate it matches udp_payload. */
static void recv_validate_udp(int fd_udp)
{
	ssize_t ret;
	static uint8_t recv_buff[MSG_LEN_MAX];

	ret = recv(fd_udp, recv_buff, payload_len, 0);
	msg_counter++;

	if (cfg_overlap) {
		if (ret != -1)
			error(1, 0, "recv: expected timeout; got %d",
				(int)ret);
		if (errno != ETIMEDOUT && errno != EAGAIN)
			error(1, errno, "recv: expected timeout: %d",
				 errno);
		return;  /* OK */
	}

	if (ret == -1)
		error(1, errno, "recv: payload_len = %d max_frag_len = %d",
			payload_len, max_frag_len);
	if (ret != payload_len)
		error(1, 0, "recv: wrong size: %d vs %d", (int)ret, payload_len);
	if (memcmp(udp_payload, recv_buff, payload_len))
		error(1, 0, "recv: wrong data");
}

static uint32_t raw_checksum(uint8_t *buf, int len, uint32_t sum)
{
	int i;

	for (i = 0; i < (len & ~1U); i += 2) {
		sum += (u_int16_t)ntohs(*((u_int16_t *)(buf + i)));
		if (sum > 0xffff)
			sum -= 0xffff;
	}

	if (i < len) {
		sum += buf[i] << 8;
		if (sum > 0xffff)
			sum -= 0xffff;
	}

	return sum;
}

static uint16_t udp_checksum(struct ip *iphdr, struct udphdr *udphdr)
{
	uint32_t sum = 0;
	uint16_t res;

	sum = raw_checksum((uint8_t *)&iphdr->ip_src, 2 * sizeof(iphdr->ip_src),
				IPPROTO_UDP + (uint32_t)(UDP_HLEN + payload_len));
	sum = raw_checksum((uint8_t *)udphdr, UDP_HLEN, sum);
	sum = raw_checksum((uint8_t *)udp_payload, payload_len, sum);
	res = 0xffff & ~sum;
	if (res)
		return htons(res);
	else
		return CSUM_MANGLED_0;
}

static uint16_t udp6_checksum(struct ip6_hdr *iphdr, struct udphdr *udphdr)
{
	uint32_t sum = 0;
	uint16_t res;

	sum = raw_checksum((uint8_t *)&iphdr->ip6_src, 2 * sizeof(iphdr->ip6_src),
				IPPROTO_UDP);
	sum = raw_checksum((uint8_t *)&udphdr->len, sizeof(udphdr->len), sum);
	sum = raw_checksum((uint8_t *)udphdr, UDP_HLEN, sum);
	sum = raw_checksum((uint8_t *)udp_payload, payload_len, sum);
	res = 0xffff & ~sum;
	if (res)
		return htons(res);
	else
		return CSUM_MANGLED_0;
}

static void send_fragment(int fd_raw, struct sockaddr *addr, socklen_t alen,
				int offset, bool ipv6)
{
	int frag_len;
	int res;
	int payload_offset = offset > 0 ? offset - UDP_HLEN : 0;
	uint8_t *frag_start = ipv6 ? ip_frame + IP6_HLEN + FRAG_HLEN :
					ip_frame + IP4_HLEN;

	if (offset == 0) {
		struct udphdr udphdr;
		udphdr.source = htons(cfg_port + 1);
		udphdr.dest = htons(cfg_port);
		udphdr.len = htons(UDP_HLEN + payload_len);
		udphdr.check = 0;
		if (ipv6)
			udphdr.check = udp6_checksum((struct ip6_hdr *)ip_frame, &udphdr);
		else
			udphdr.check = udp_checksum((struct ip *)ip_frame, &udphdr);
		memcpy(frag_start, &udphdr, UDP_HLEN);
	}

	if (ipv6) {
		struct ip6_hdr *ip6hdr = (struct ip6_hdr *)ip_frame;
		struct ip6_frag *fraghdr = (struct ip6_frag *)(ip_frame + IP6_HLEN);
		if (payload_len - payload_offset <= max_frag_len && offset > 0) {
			/* This is the last fragment. */
			frag_len = FRAG_HLEN + payload_len - payload_offset;
			fraghdr->ip6f_offlg = htons(offset);
		} else {
			frag_len = FRAG_HLEN + max_frag_len;
			fraghdr->ip6f_offlg = htons(offset | IP6_MF);
		}
		ip6hdr->ip6_plen = htons(frag_len);
		if (offset == 0)
			memcpy(frag_start + UDP_HLEN, udp_payload,
				frag_len - FRAG_HLEN - UDP_HLEN);
		else
			memcpy(frag_start, udp_payload + payload_offset,
				frag_len - FRAG_HLEN);
		frag_len += IP6_HLEN;
	} else {
		struct ip *iphdr = (struct ip *)ip_frame;
		if (payload_len - payload_offset <= max_frag_len && offset > 0) {
			/* This is the last fragment. */
			frag_len = IP4_HLEN + payload_len - payload_offset;
			iphdr->ip_off = htons(offset / 8);
		} else {
			frag_len = IP4_HLEN + max_frag_len;
			iphdr->ip_off = htons(offset / 8 | IP4_MF);
		}
		iphdr->ip_len = htons(frag_len);
		if (offset == 0)
			memcpy(frag_start + UDP_HLEN, udp_payload,
				frag_len - IP4_HLEN - UDP_HLEN);
		else
			memcpy(frag_start, udp_payload + payload_offset,
				frag_len - IP4_HLEN);
	}

	res = sendto(fd_raw, ip_frame, frag_len, 0, addr, alen);
	if (res < 0)
		error(1, errno, "send_fragment");
	if (res != frag_len)
		error(1, 0, "send_fragment: %d vs %d", res, frag_len);

	frag_counter++;
}

static void send_udp_frags(int fd_raw, struct sockaddr *addr,
				socklen_t alen, bool ipv6)
{
	struct ip *iphdr = (struct ip *)ip_frame;
	struct ip6_hdr *ip6hdr = (struct ip6_hdr *)ip_frame;
	const bool ipv4 = !ipv6;
	int res;
	int offset;
	int frag_len;

	/* Send the UDP datagram using raw IP fragments: the 0th fragment
	 * has the UDP header; other fragments are pieces of udp_payload
	 * split in chunks of frag_len size.
	 *
	 * Odd fragments (1st, 3rd, 5th, etc.) are sent out first, then
	 * even fragments (0th, 2nd, etc.) are sent out.
	 */
	if (ipv6) {
		struct ip6_frag *fraghdr = (struct ip6_frag *)(ip_frame + IP6_HLEN);
		((struct sockaddr_in6 *)addr)->sin6_port = 0;
		memset(ip6hdr, 0, sizeof(*ip6hdr));
		ip6hdr->ip6_flow = htonl(6<<28);  /* Version. */
		ip6hdr->ip6_nxt = IPPROTO_FRAGMENT;
		ip6hdr->ip6_hops = 255;
		ip6hdr->ip6_src = addr6;
		ip6hdr->ip6_dst = addr6;
		fraghdr->ip6f_nxt = IPPROTO_UDP;
		fraghdr->ip6f_reserved = 0;
		fraghdr->ip6f_ident = htonl(ip_id++);
	} else {
		memset(iphdr, 0, sizeof(*iphdr));
		iphdr->ip_hl = 5;
		iphdr->ip_v = 4;
		iphdr->ip_tos = 0;
		iphdr->ip_id = htons(ip_id++);
		iphdr->ip_ttl = 0x40;
		iphdr->ip_p = IPPROTO_UDP;
		iphdr->ip_src.s_addr = htonl(INADDR_LOOPBACK);
		iphdr->ip_dst = addr4;
		iphdr->ip_sum = 0;
	}

	/* Occasionally test in-order fragments. */
	if (!cfg_overlap && (rand() % 100 < 15)) {
		offset = 0;
		while (offset < (UDP_HLEN + payload_len)) {
			send_fragment(fd_raw, addr, alen, offset, ipv6);
			offset += max_frag_len;
		}
		return;
	}

	/* Occasionally test IPv4 "runs" (see net/ipv4/ip_fragment.c) */
	if (ipv4 && !cfg_overlap && (rand() % 100 < 20) &&
			(payload_len > 9 * max_frag_len)) {
		offset = 6 * max_frag_len;
		while (offset < (UDP_HLEN + payload_len)) {
			send_fragment(fd_raw, addr, alen, offset, ipv6);
			offset += max_frag_len;
		}
		offset = 3 * max_frag_len;
		while (offset < 6 * max_frag_len) {
			send_fragment(fd_raw, addr, alen, offset, ipv6);
			offset += max_frag_len;
		}
		offset = 0;
		while (offset < 3 * max_frag_len) {
			send_fragment(fd_raw, addr, alen, offset, ipv6);
			offset += max_frag_len;
		}
		return;
	}

	/* Odd fragments. */
	offset = max_frag_len;
	while (offset < (UDP_HLEN + payload_len)) {
		send_fragment(fd_raw, addr, alen, offset, ipv6);
		/* IPv4 ignores duplicates, so randomly send a duplicate. */
		if (ipv4 && (1 == rand() % 100))
			send_fragment(fd_raw, addr, alen, offset, ipv6);
		offset += 2 * max_frag_len;
	}

	if (cfg_overlap) {
		/* Send an extra random fragment. */
		if (ipv6) {
			struct ip6_frag *fraghdr = (struct ip6_frag *)(ip_frame + IP6_HLEN);
			/* sendto() returns EINVAL if offset + frag_len is too small. */
			offset = rand() % (UDP_HLEN + payload_len - 1);
			frag_len = max_frag_len + rand() % 256;
			/* In IPv6 if !!(frag_len % 8), the fragment is dropped. */
			frag_len &= ~0x7;
			fraghdr->ip6f_offlg = htons(offset / 8 | IP6_MF);
			ip6hdr->ip6_plen = htons(frag_len);
			frag_len += IP6_HLEN;
		} else {
			/* In IPv4, duplicates and some fragments completely inside
			 * previously sent fragments are dropped/ignored. So
			 * random offset and frag_len can result in a dropped
			 * fragment instead of a dropped queue/packet. So we
			 * hard-code offset and frag_len.
			 *
			 * See ade446403bfb ("net: ipv4: do not handle duplicate
			 * fragments as overlapping").
			 */
			if (max_frag_len * 4 < payload_len || max_frag_len < 16) {
				/* not enough payload to play with random offset and frag_len. */
				offset = 8;
				frag_len = IP4_HLEN + UDP_HLEN + max_frag_len;
			} else {
				offset = rand() % (payload_len / 2);
				frag_len = 2 * max_frag_len + 1 + rand() % 256;
			}
			iphdr->ip_off = htons(offset / 8 | IP4_MF);
			iphdr->ip_len = htons(frag_len);
		}
		res = sendto(fd_raw, ip_frame, frag_len, 0, addr, alen);
		if (res < 0)
			error(1, errno, "sendto overlap: %d", frag_len);
		if (res != frag_len)
			error(1, 0, "sendto overlap: %d vs %d", (int)res, frag_len);
		frag_counter++;
	}

	/* Event fragments. */
	offset = 0;
	while (offset < (UDP_HLEN + payload_len)) {
		send_fragment(fd_raw, addr, alen, offset, ipv6);
		/* IPv4 ignores duplicates, so randomly send a duplicate. */
		if (ipv4 && (1 == rand() % 100))
			send_fragment(fd_raw, addr, alen, offset, ipv6);
		offset += 2 * max_frag_len;
	}
}

static void run_test(struct sockaddr *addr, socklen_t alen, bool ipv6)
{
	int fd_tx_raw, fd_rx_udp;
	/* Frag queue timeout is set to one second in the calling script;
	 * socket timeout should be just a bit longer to avoid tests interfering
	 * with each other.
	 */
	struct timeval tv = { .tv_sec = 1, .tv_usec = 10 };
	int idx;
	int min_frag_len = ipv6 ? 1280 : 8;

	/* Initialize the payload. */
	for (idx = 0; idx < MSG_LEN_MAX; ++idx)
		udp_payload[idx] = idx % 256;

	/* Open sockets. */
	fd_tx_raw = socket(addr->sa_family, SOCK_RAW, IPPROTO_RAW);
	if (fd_tx_raw == -1)
		error(1, errno, "socket tx_raw");

	fd_rx_udp = socket(addr->sa_family, SOCK_DGRAM, 0);
	if (fd_rx_udp == -1)
		error(1, errno, "socket rx_udp");
	if (bind(fd_rx_udp, addr, alen))
		error(1, errno, "bind");
	/* Fail fast. */
	if (setsockopt(fd_rx_udp, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)))
		error(1, errno, "setsockopt rcv timeout");

	for (payload_len = min_frag_len; payload_len < MSG_LEN_MAX;
			payload_len += (rand() % 4096)) {
		if (cfg_verbose)
			printf("payload_len: %d\n", payload_len);

		if (cfg_overlap) {
			/* With overlaps, one send/receive pair below takes
			 * at least one second (== timeout) to run, so there
			 * is not enough test time to run a nested loop:
			 * the full overlap test takes 20-30 seconds.
			 */
			max_frag_len = min_frag_len +
				rand() % (1500 - FRAG_HLEN - min_frag_len);
			send_udp_frags(fd_tx_raw, addr, alen, ipv6);
			recv_validate_udp(fd_rx_udp);
		} else {
			/* Without overlaps, each packet reassembly (== one
			 * send/receive pair below) takes very little time to
			 * run, so we can easily afford more thourough testing
			 * with a nested loop: the full non-overlap test takes
			 * less than one second).
			 */
			max_frag_len = min_frag_len;
			do {
				send_udp_frags(fd_tx_raw, addr, alen, ipv6);
				recv_validate_udp(fd_rx_udp);
				max_frag_len += 8 * (rand() % 8);
			} while (max_frag_len < (1500 - FRAG_HLEN) &&
				 max_frag_len <= payload_len);
		}
	}

	/* Cleanup. */
	if (close(fd_tx_raw))
		error(1, errno, "close tx_raw");
	if (close(fd_rx_udp))
		error(1, errno, "close rx_udp");

	if (cfg_verbose)
		printf("processed %d messages, %d fragments\n",
			msg_counter, frag_counter);

	fprintf(stderr, "PASS\n");
}


static void run_test_v4(void)
{
	struct sockaddr_in addr = {0};

	addr.sin_family = AF_INET;
	addr.sin_port = htons(cfg_port);
	addr.sin_addr = addr4;

	run_test((void *)&addr, sizeof(addr), false /* !ipv6 */);
}

static void run_test_v6(void)
{
	struct sockaddr_in6 addr = {0};

	addr.sin6_family = AF_INET6;
	addr.sin6_port = htons(cfg_port);
	addr.sin6_addr = addr6;

	run_test((void *)&addr, sizeof(addr), true /* ipv6 */);
}

static void parse_opts(int argc, char **argv)
{
	int c;

	while ((c = getopt(argc, argv, "46ov")) != -1) {
		switch (c) {
		case '4':
			cfg_do_ipv4 = true;
			break;
		case '6':
			cfg_do_ipv6 = true;
			break;
		case 'o':
			cfg_overlap = true;
			break;
		case 'v':
			cfg_verbose = true;
			break;
		default:
			error(1, 0, "%s: parse error", argv[0]);
		}
	}
}

int main(int argc, char **argv)
{
	parse_opts(argc, argv);
	seed = time(NULL);
	srand(seed);
	/* Print the seed to track/reproduce potential failures. */
	printf("seed = %d\n", seed);

	if (cfg_do_ipv4)
		run_test_v4();
	if (cfg_do_ipv6)
		run_test_v6();

	return 0;
}
OpenPOWER on IntegriCloud