1 /* 2 * Copyright (c) 1993, 1994, 1995, 1996, 1997 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that: (1) source code distributions 7 * retain the above copyright notice and this paragraph in its entirety, (2) 8 * distributions including binary code include the above copyright notice and 9 * this paragraph in its entirety in the documentation or other materials 10 * provided with the distribution, and (3) all advertising materials mentioning 11 * features or use of this software display the following acknowledgement: 12 * ``This product includes software developed by the University of California, 13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 14 * the University nor the names of its contributors may be used to endorse 15 * or promote products derived from this software without specific prior 16 * written permission. 17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 20 * 21 * savefile.c - supports offline use of tcpdump 22 * Extraction/creation by Jeffrey Mogul, DECWRL 23 * Modified by Steve McCanne, LBL. 24 * 25 * Used to save the received packet headers, after filtering, to 26 * a file, and then read them later. 27 * The first record in the file contains saved values for the machine 28 * dependent values so we can print the dump file on any architecture. 29 */ 30 31 #ifndef lint 32 static const char rcsid[] _U_ = 33 "@(#) Header: /tcpdump/master/libpcap/savefile.c,v 1.183 2008-12-23 20:13:29 guy Exp (LBL)"; 34 #endif 35 36 #ifdef HAVE_CONFIG_H 37 #include "config.h" 38 #endif 39 40 #ifdef WIN32 41 #include <pcap-stdinc.h> 42 #else /* WIN32 */ 43 #if HAVE_INTTYPES_H 44 #include <inttypes.h> 45 #elif HAVE_STDINT_H 46 #include <stdint.h> 47 #endif 48 #ifdef HAVE_SYS_BITYPES_H 49 #include <sys/bitypes.h> 50 #endif 51 #include <sys/types.h> 52 #endif /* WIN32 */ 53 54 #include <errno.h> 55 #include <memory.h> 56 #include <stdio.h> 57 #include <stdlib.h> 58 #include <string.h> 59 60 #include "pcap-int.h" 61 #include "pcap/usb.h" 62 63 #ifdef HAVE_OS_PROTO_H 64 #include "os-proto.h" 65 #endif 66 67 #include "sf-pcap.h" 68 #include "sf-pcap-ng.h" 69 70 /* 71 * Setting O_BINARY on DOS/Windows is a bit tricky 72 */ 73 #if defined(WIN32) 74 #define SET_BINMODE(f) _setmode(_fileno(f), _O_BINARY) 75 #elif defined(MSDOS) 76 #if defined(__HIGHC__) 77 #define SET_BINMODE(f) setmode(f, O_BINARY) 78 #else 79 #define SET_BINMODE(f) setmode(fileno(f), O_BINARY) 80 #endif 81 #endif 82 83 static int 84 sf_getnonblock(pcap_t *p, char *errbuf) 85 { 86 /* 87 * This is a savefile, not a live capture file, so never say 88 * it's in non-blocking mode. 89 */ 90 return (0); 91 } 92 93 static int 94 sf_setnonblock(pcap_t *p, int nonblock, char *errbuf) 95 { 96 /* 97 * This is a savefile, not a live capture file, so ignore 98 * requests to put it in non-blocking mode. 99 */ 100 return (0); 101 } 102 103 static int 104 sf_stats(pcap_t *p, struct pcap_stat *ps) 105 { 106 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 107 "Statistics aren't available from savefiles"); 108 return (-1); 109 } 110 111 #ifdef WIN32 112 static int 113 sf_setbuff(pcap_t *p, int dim) 114 { 115 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 116 "The kernel buffer size cannot be set while reading from a file"); 117 return (-1); 118 } 119 120 static int 121 sf_setmode(pcap_t *p, int mode) 122 { 123 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 124 "impossible to set mode while reading from a file"); 125 return (-1); 126 } 127 128 static int 129 sf_setmintocopy(pcap_t *p, int size) 130 { 131 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 132 "The mintocopy parameter cannot be set while reading from a file"); 133 return (-1); 134 } 135 #endif 136 137 static int 138 sf_inject(pcap_t *p, const void *buf _U_, size_t size _U_) 139 { 140 strlcpy(p->errbuf, "Sending packets isn't supported on savefiles", 141 PCAP_ERRBUF_SIZE); 142 return (-1); 143 } 144 145 /* 146 * Set direction flag: Which packets do we accept on a forwarding 147 * single device? IN, OUT or both? 148 */ 149 static int 150 sf_setdirection(pcap_t *p, pcap_direction_t d) 151 { 152 snprintf(p->errbuf, sizeof(p->errbuf), 153 "Setting direction is not supported on savefiles"); 154 return (-1); 155 } 156 157 static void 158 sf_cleanup(pcap_t *p) 159 { 160 if (p->sf.rfile != stdin) 161 (void)fclose(p->sf.rfile); 162 if (p->buffer != NULL) 163 free(p->buffer); 164 } 165 166 pcap_t * 167 pcap_open_offline(const char *fname, char *errbuf) 168 { 169 FILE *fp; 170 pcap_t *p; 171 172 if (fname[0] == '-' && fname[1] == '\0') 173 { 174 fp = stdin; 175 #if defined(WIN32) || defined(MSDOS) 176 /* 177 * We're reading from the standard input, so put it in binary 178 * mode, as savefiles are binary files. 179 */ 180 SET_BINMODE(fp); 181 #endif 182 } 183 else { 184 #if !defined(WIN32) && !defined(MSDOS) 185 fp = fopen(fname, "r"); 186 #else 187 fp = fopen(fname, "rb"); 188 #endif 189 if (fp == NULL) { 190 snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", fname, 191 pcap_strerror(errno)); 192 return (NULL); 193 } 194 } 195 p = pcap_fopen_offline(fp, errbuf); 196 if (p == NULL) { 197 if (fp != stdin) 198 fclose(fp); 199 } 200 return (p); 201 } 202 203 #ifdef WIN32 204 pcap_t* pcap_hopen_offline(intptr_t osfd, char *errbuf) 205 { 206 int fd; 207 FILE *file; 208 209 fd = _open_osfhandle(osfd, _O_RDONLY); 210 if ( fd < 0 ) 211 { 212 snprintf(errbuf, PCAP_ERRBUF_SIZE, pcap_strerror(errno)); 213 return NULL; 214 } 215 216 file = _fdopen(fd, "rb"); 217 if ( file == NULL ) 218 { 219 snprintf(errbuf, PCAP_ERRBUF_SIZE, pcap_strerror(errno)); 220 return NULL; 221 } 222 223 return pcap_fopen_offline(file, errbuf); 224 } 225 #endif 226 227 static int (*check_headers[])(pcap_t *, bpf_u_int32, FILE *, char *) = { 228 pcap_check_header, 229 pcap_ng_check_header 230 }; 231 232 #define N_FILE_TYPES (sizeof check_headers / sizeof check_headers[0]) 233 234 #ifdef WIN32 235 static 236 #endif 237 pcap_t * 238 pcap_fopen_offline(FILE *fp, char *errbuf) 239 { 240 register pcap_t *p; 241 bpf_u_int32 magic; 242 size_t amt_read; 243 u_int i; 244 245 p = pcap_create_common("(savefile)", errbuf); 246 if (p == NULL) 247 return (NULL); 248 249 /* 250 * Read the first 4 bytes of the file; the network analyzer dump 251 * file formats we support (pcap and pcap-ng), and several other 252 * formats we might support in the future (such as snoop, DOS and 253 * Windows Sniffer, and Microsoft Network Monitor) all have magic 254 * numbers that are unique in their first 4 bytes. 255 */ 256 amt_read = fread((char *)&magic, 1, sizeof(magic), fp); 257 if (amt_read != sizeof(magic)) { 258 if (ferror(fp)) { 259 snprintf(errbuf, PCAP_ERRBUF_SIZE, 260 "error reading dump file: %s", 261 pcap_strerror(errno)); 262 } else { 263 snprintf(errbuf, PCAP_ERRBUF_SIZE, 264 "truncated dump file; tried to read %lu file header bytes, only got %lu", 265 (unsigned long)sizeof(magic), 266 (unsigned long)amt_read); 267 } 268 goto bad; 269 } 270 271 /* 272 * Try all file types. 273 */ 274 for (i = 0; i < N_FILE_TYPES; i++) { 275 switch ((*check_headers[i])(p, magic, fp, errbuf)) { 276 277 case -1: 278 /* 279 * Error trying to read the header. 280 */ 281 goto bad; 282 283 case 1: 284 /* 285 * Yup, that's it. 286 */ 287 goto found; 288 } 289 } 290 291 /* 292 * Well, who knows what this mess is.... 293 */ 294 snprintf(errbuf, PCAP_ERRBUF_SIZE, "unknown file format"); 295 goto bad; 296 297 found: 298 p->sf.rfile = fp; 299 300 #ifdef PCAP_FDDIPAD 301 /* Padding only needed for live capture fcode */ 302 p->fddipad = 0; 303 #endif 304 305 #if !defined(WIN32) && !defined(MSDOS) 306 /* 307 * You can do "select()" and "poll()" on plain files on most 308 * platforms, and should be able to do so on pipes. 309 * 310 * You can't do "select()" on anything other than sockets in 311 * Windows, so, on Win32 systems, we don't have "selectable_fd". 312 */ 313 p->selectable_fd = fileno(fp); 314 #endif 315 316 p->read_op = pcap_offline_read; 317 p->inject_op = sf_inject; 318 p->setfilter_op = install_bpf_program; 319 p->setdirection_op = sf_setdirection; 320 p->set_datalink_op = NULL; /* we don't support munging link-layer headers */ 321 p->getnonblock_op = sf_getnonblock; 322 p->setnonblock_op = sf_setnonblock; 323 p->stats_op = sf_stats; 324 #ifdef WIN32 325 p->setbuff_op = sf_setbuff; 326 p->setmode_op = sf_setmode; 327 p->setmintocopy_op = sf_setmintocopy; 328 #endif 329 p->cleanup_op = sf_cleanup; 330 p->activated = 1; 331 332 return (p); 333 bad: 334 free(p); 335 return (NULL); 336 } 337 338 /* 339 * Read packets from a capture file, and call the callback for each 340 * packet. 341 * If cnt > 0, return after 'cnt' packets, otherwise continue until eof. 342 */ 343 int 344 pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user) 345 { 346 struct bpf_insn *fcode; 347 int status = 0; 348 int n = 0; 349 u_char *data; 350 351 while (status == 0) { 352 struct pcap_pkthdr h; 353 354 /* 355 * Has "pcap_breakloop()" been called? 356 * If so, return immediately - if we haven't read any 357 * packets, clear the flag and return -2 to indicate 358 * that we were told to break out of the loop, otherwise 359 * leave the flag set, so that the *next* call will break 360 * out of the loop without having read any packets, and 361 * return the number of packets we've processed so far. 362 */ 363 if (p->break_loop) { 364 if (n == 0) { 365 p->break_loop = 0; 366 return (-2); 367 } else 368 return (n); 369 } 370 371 status = p->sf.next_packet_op(p, &h, &data); 372 if (status) { 373 if (status == 1) 374 return (0); 375 return (status); 376 } 377 378 if ((fcode = p->fcode.bf_insns) == NULL || 379 bpf_filter(fcode, p->buffer, h.len, h.caplen)) { 380 (*callback)(user, &h, data); 381 if (++n >= cnt && cnt > 0) 382 break; 383 } 384 } 385 /*XXX this breaks semantics tcpslice expects */ 386 return (n); 387 } 388