1/*	$NetBSD: ip4_frag_1.c,v 1.1 2010/07/13 22:13:18 rmind Exp $	*/
2
3/*-
4 * Copyright (c) 2010 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software developed for The NetBSD Foundation
8 * by Mindaugas Rasiukevicius <rmind at NetBSD org>.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32/*
33 * Test various cases of IPv4 reassembly.
34 */
35
36#include <sys/cdefs.h>
37
38#include <stdio.h>
39#include <stdlib.h>
40#include <string.h>
41#include <stddef.h>
42#include <unistd.h>
43#include <netdb.h>
44#include <assert.h>
45#include <err.h>
46
47#include <sys/socket.h>
48#include <netinet/in_systm.h>
49#include <netinet/in.h>
50#include <netinet/ip.h>
51#include <netinet/udp.h>
52#include <netinet/ip_icmp.h>
53#include <arpa/inet.h>
54
55#define	IP_SIZE			sizeof(struct ip)
56#define	ICMP_SIZE		offsetof(struct icmp, icmp_ip)
57
58static void *
59xalloc(size_t sz)
60{
61	void *ptr = calloc(1, sz);
62
63	if (ptr == NULL) {
64		err(EXIT_FAILURE, "calloc");
65	}
66	return ptr;
67}
68
69static int
70create_socket(void)
71{
72	int s, val = 1;
73
74	s = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
75	if (s == -1) {
76		err(EXIT_FAILURE, "socket");
77	}
78	if (setsockopt(s, IPPROTO_IP, IP_HDRINCL, &val, sizeof(val)) == -1) {
79		err(EXIT_FAILURE, "setsockopt");
80	}
81	return s;
82}
83
84void *
85create_ip_packet(in_addr_t target, int foff, size_t addlen)
86{
87	struct ip *ip;
88	unsigned int n;
89	uint8_t *data;
90	int first;
91
92	/* Header at zero offset - first fragment. */
93	first = ((foff & IP_MF) == 0);
94	if (first) {
95		assert(addlen >= ICMP_SIZE);
96		addlen -= ICMP_SIZE;
97	}
98	ip = xalloc(IP_SIZE + addlen);
99
100	/*
101	 * IP header.
102	 * Note: ip_len and ip_off shall be in host byte order.
103	 */
104	ip->ip_v = IPVERSION;
105	ip->ip_hl = 5;
106	ip->ip_tos = 0;
107	ip->ip_len = (5 << 2) + addlen;
108	ip->ip_id = htons(1);
109	ip->ip_off = foff;
110	ip->ip_ttl = 64;
111	ip->ip_p = IPPROTO_ICMP;
112	ip->ip_sum = 0;
113
114	ip->ip_src.s_addr = INADDR_ANY;
115	ip->ip_dst.s_addr = target;
116
117	/* Fill in some data. */
118	data = (void *)(ip + 1);
119	if (first) {
120		struct icmp *icmp = (void *)data;
121		icmp->icmp_type = ICMP_ECHO;
122		icmp->icmp_code = 0;
123		icmp->icmp_cksum = 0;
124		n = ICMP_SIZE;
125	} else {
126		n = 0;
127	}
128	for (data += n; n < addlen; n++) {
129		*data = (0xf & n);
130		data++;
131	}
132	return (void *)ip;
133}
134
135void
136send_packet(int s, void *p, in_addr_t target)
137{
138	struct ip *ip = (struct ip *)p;
139	struct sockaddr_in addr;
140	ssize_t ret;
141
142	memset(&addr, 0, sizeof(addr));
143	addr.sin_family = AF_INET;
144	addr.sin_addr.s_addr = target;
145
146	/* Note: total length was set host byte-order. */
147	ret = sendto(s, p, ip->ip_len, 0,
148	    (struct sockaddr *)&addr, sizeof(struct sockaddr_in));
149	if (ret == -1) {
150		err(EXIT_FAILURE, "sendto");
151	}
152	free(p);
153}
154
155void
156test_case_0(int sock, in_addr_t target)
157{
158	void *p;
159
160	/*
161	 * Case 0: normal reassembly.
162	 * => IP_STAT_FRAGMENTS
163	 */
164
165	p = create_ip_packet(target, 0 | IP_MF, 1480);
166	send_packet(sock, p, target);
167
168	p = create_ip_packet(target, 185, 1480);
169	send_packet(sock, p, target);
170}
171
172void
173test_case_1(int sock, in_addr_t target)
174{
175	void *p;
176
177	/*
178	 * Case 1: ip_len of the first fragment and ip_off + hlen of other
179	 * fragments should be at least 68 (IP_MINFRAGSIZE - 1) bytes.
180	 * => IP_STAT_BADFRAGS (malformed)
181	 */
182
183	/* 20 + 48 == 68, OK */
184	p = create_ip_packet(target, 0 | IP_MF, 48);
185	send_packet(sock, p, target);
186
187	/* 20 + (5 * 8) = 60 < 68, ERR */
188	p = create_ip_packet(target, 6 - 1, 8);
189	send_packet(sock, p, target);
190}
191
192void
193test_case_2(int sock, in_addr_t target)
194{
195	void *p;
196	struct ip *ip;
197
198	/*
199	 * Case 2: mismatch of TOS.
200	 * => IP_STAT_BADFRAGS (malformed)
201	 */
202
203	p = create_ip_packet(target, 0 | IP_MF, 48);
204	ip = (struct ip *)p;
205	ip->ip_tos = 123;
206	send_packet(sock, p, target);
207
208	p = create_ip_packet(target, 6, 48);
209	send_packet(sock, p, target);
210}
211
212void
213test_case_3(int sock, in_addr_t target)
214{
215	void *p;
216
217	/*
218	 * Case 3: data length is not multiple of 8 bytes.
219	 * => IP_STAT_BADFRAGS (malformed)
220	 */
221
222	p = create_ip_packet(target, 0 | IP_MF, 48);
223	send_packet(sock, p, target);
224
225	/* (48 + 1) & 0x7 != 0, ERR */
226	p = create_ip_packet(target, 6, 48 + 1);
227	send_packet(sock, p, target);
228}
229
230void
231test_case_4(int sock, in_addr_t target)
232{
233	void *p;
234
235	/*
236	 * Case 4: fragment covering previous (duplicate).
237	 * => IP_STAT_FRAGDROPPED (dup, out of space)
238	 */
239
240	p = create_ip_packet(target, 0 | IP_MF, 48);
241	send_packet(sock, p, target);
242
243	p = create_ip_packet(target, 6 | IP_MF, 96);
244	send_packet(sock, p, target);
245
246	p = create_ip_packet(target, 6, 48);
247	send_packet(sock, p, target);
248}
249
250void
251test_case_5(int sock, in_addr_t target)
252{
253	void *p;
254	int cnt, left, off;
255
256	/*
257	 * Case 5: construct packet larger than IP_MAXPACKET.
258	 * => IP_STAT_TOOLONG (with length > max ip packet size)
259	 */
260
261	/*
262	 * Assumptions:
263	 * - 1500 MTU.  Minus IP header - 1480.
264	 * - Bytes left: 65535 - (1480 * 44) = 415.
265	 */
266	cnt = IP_MAXPACKET / 1480;
267	left = IP_MAXPACKET - (1480 * cnt);
268	left = (left / 8) * 8;
269
270	for (off = 0; cnt != 0; cnt--) {
271		p = create_ip_packet(target, off | IP_MF, 1480);
272		send_packet(sock, p, target);
273		off += (1480 >> 3);
274	}
275	/* Add 8 bytes and thus cross IP_MAXPACKET limit. */
276	p = create_ip_packet(target, off, left + 8);
277	send_packet(sock, p, target);
278}
279
280void
281test_case_6(int sock, in_addr_t target)
282{
283	struct ip *ip;
284	void *p;
285
286	/*
287	 * Case 6: cause a fragment timeout.
288	 * => IP_STAT_FRAGTIMEOUT (fragments dropped after timeout)
289	 */
290
291	p = create_ip_packet(target, 0 | IP_MF, 48);
292	ip = (struct ip *)p;
293	ip->ip_id = htons(321);
294	send_packet(sock, p, target);
295	/*
296	 * Missing non-MF packet - timeout.
297	 */
298}
299
300int
301main(int argc, char **argv)
302{
303	struct hostent *he;
304	in_addr_t target;
305	int sock;
306
307	if (argc < 2) {
308		printf("%s: <target host>\n", argv[0]);
309		exit(EXIT_SUCCESS);
310	}
311
312	he = gethostbyname(argv[1]);
313	if (he == NULL) {
314		err(EXIT_FAILURE, "gethostbyname");
315	}
316	memcpy(&target, he->h_addr, sizeof(target));
317
318	sock = create_socket();
319
320	test_case_0(sock, target);
321	test_case_1(sock, target);
322	test_case_2(sock, target);
323	test_case_3(sock, target);
324	test_case_4(sock, target);
325	test_case_5(sock, target);
326	test_case_6(sock, target);
327
328	close(sock);
329
330	return 0;
331}
332