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 58 static void * 59 xalloc(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 69 static int 70 create_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 84 void * 85 create_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[n] = (0xf & n); 130 } 131 return (void *)ip; 132 } 133 134 void 135 send_packet(int s, void *p, in_addr_t target) 136 { 137 struct ip *ip = (struct ip *)p; 138 struct sockaddr_in addr; 139 ssize_t ret; 140 141 memset(&addr, 0, sizeof(addr)); 142 addr.sin_family = AF_INET; 143 addr.sin_addr.s_addr = target; 144 145 /* Note: total length was set host byte-order. */ 146 ret = sendto(s, p, ip->ip_len, 0, 147 (struct sockaddr *)&addr, sizeof(struct sockaddr_in)); 148 if (ret == -1) { 149 err(EXIT_FAILURE, "sendto"); 150 } 151 free(p); 152 } 153 154 void 155 test_case_0(int sock, in_addr_t target) 156 { 157 void *p; 158 159 /* 160 * Case 0: normal reassembly. 161 * => IP_STAT_FRAGMENTS 162 */ 163 164 p = create_ip_packet(target, 0 | IP_MF, 1480); 165 send_packet(sock, p, target); 166 167 p = create_ip_packet(target, 185, 1480); 168 send_packet(sock, p, target); 169 } 170 171 void 172 test_case_1(int sock, in_addr_t target) 173 { 174 void *p; 175 176 /* 177 * Case 1: ip_len of the first fragment and ip_off + hlen of other 178 * fragments should be at least 68 (IP_MINFRAGSIZE - 1) bytes. 179 * => IP_STAT_BADFRAGS (malformed) 180 */ 181 182 /* 20 + 48 == 68, OK */ 183 p = create_ip_packet(target, 0 | IP_MF, 48); 184 send_packet(sock, p, target); 185 186 /* 20 + (5 * 8) = 60 < 68, ERR */ 187 p = create_ip_packet(target, 6 - 1, 8); 188 send_packet(sock, p, target); 189 } 190 191 void 192 test_case_2(int sock, in_addr_t target) 193 { 194 void *p; 195 struct ip *ip; 196 197 /* 198 * Case 2: mismatch of TOS. 199 * => IP_STAT_BADFRAGS (malformed) 200 */ 201 202 p = create_ip_packet(target, 0 | IP_MF, 48); 203 ip = (struct ip *)p; 204 ip->ip_tos = 123; 205 send_packet(sock, p, target); 206 207 p = create_ip_packet(target, 6, 48); 208 send_packet(sock, p, target); 209 } 210 211 void 212 test_case_3(int sock, in_addr_t target) 213 { 214 void *p; 215 216 /* 217 * Case 3: data length is not multiple of 8 bytes. 218 * => IP_STAT_BADFRAGS (malformed) 219 */ 220 221 p = create_ip_packet(target, 0 | IP_MF, 48); 222 send_packet(sock, p, target); 223 224 /* (48 + 1) & 0x7 != 0, ERR */ 225 p = create_ip_packet(target, 6, 48 + 1); 226 send_packet(sock, p, target); 227 } 228 229 void 230 test_case_4(int sock, in_addr_t target) 231 { 232 void *p; 233 234 /* 235 * Case 4: fragment covering previous (duplicate). 236 * => IP_STAT_FRAGDROPPED (dup, out of space) 237 */ 238 239 p = create_ip_packet(target, 0 | IP_MF, 48); 240 send_packet(sock, p, target); 241 242 p = create_ip_packet(target, 6 | IP_MF, 96); 243 send_packet(sock, p, target); 244 245 p = create_ip_packet(target, 6, 48); 246 send_packet(sock, p, target); 247 } 248 249 void 250 test_case_5(int sock, in_addr_t target) 251 { 252 void *p; 253 int cnt, left, off; 254 255 /* 256 * Case 5: construct packet larger than IP_MAXPACKET. 257 * => IP_STAT_TOOLONG (with length > max ip packet size) 258 */ 259 260 /* 261 * Assumptions: 262 * - 1500 MTU. Minus IP header - 1480. 263 * - Bytes left: 65535 - (1480 * 44) = 415. 264 */ 265 cnt = IP_MAXPACKET / 1480; 266 left = IP_MAXPACKET - (1480 * cnt); 267 left = (left / 8) * 8; 268 269 for (off = 0; cnt != 0; cnt--) { 270 p = create_ip_packet(target, off | IP_MF, 1480); 271 send_packet(sock, p, target); 272 off += (1480 >> 3); 273 } 274 /* Add 8 bytes and thus cross IP_MAXPACKET limit. */ 275 p = create_ip_packet(target, off, left + 8); 276 send_packet(sock, p, target); 277 } 278 279 void 280 test_case_6(int sock, in_addr_t target) 281 { 282 struct ip *ip; 283 void *p; 284 285 /* 286 * Case 6: cause a fragment timeout. 287 * => IP_STAT_FRAGTIMEOUT (fragments dropped after timeout) 288 */ 289 290 p = create_ip_packet(target, 0 | IP_MF, 48); 291 ip = (struct ip *)p; 292 ip->ip_id = htons(321); 293 send_packet(sock, p, target); 294 /* 295 * Missing non-MF packet - timeout. 296 */ 297 } 298 299 int 300 main(int argc, char **argv) 301 { 302 struct hostent *he; 303 in_addr_t target; 304 int sock; 305 306 if (argc < 2) { 307 printf("%s: <target host>\n", argv[0]); 308 exit(EXIT_SUCCESS); 309 } 310 311 he = gethostbyname(argv[1]); 312 if (he == NULL) { 313 err(EXIT_FAILURE, "gethostbyname"); 314 } 315 memcpy(&target, he->h_addr, sizeof(target)); 316 317 sock = create_socket(); 318 319 test_case_0(sock, target); 320 test_case_1(sock, target); 321 test_case_2(sock, target); 322 test_case_3(sock, target); 323 test_case_4(sock, target); 324 test_case_5(sock, target); 325 test_case_6(sock, target); 326 327 close(sock); 328 329 return 0; 330 } 331