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 reject 98 * requests to put it in non-blocking mode. (If it's a 99 * pipe, it could be put in non-blocking mode, but that 100 * would significantly complicate the code to read packets, 101 * as it would have to handle reading partial packets and 102 * keeping the state of the read.) 103 */ 104 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 105 "Savefiles cannot be put into non-blocking mode"); 106 return (-1); 107 } 108 109 static int 110 sf_stats(pcap_t *p, struct pcap_stat *ps) 111 { 112 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 113 "Statistics aren't available from savefiles"); 114 return (-1); 115 } 116 117 #ifdef WIN32 118 static int 119 sf_setbuff(pcap_t *p, int dim) 120 { 121 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 122 "The kernel buffer size cannot be set while reading from a file"); 123 return (-1); 124 } 125 126 static int 127 sf_setmode(pcap_t *p, int mode) 128 { 129 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 130 "impossible to set mode while reading from a file"); 131 return (-1); 132 } 133 134 static int 135 sf_setmintocopy(pcap_t *p, int size) 136 { 137 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 138 "The mintocopy parameter cannot be set while reading from a file"); 139 return (-1); 140 } 141 #endif 142 143 static int 144 sf_inject(pcap_t *p, const void *buf _U_, size_t size _U_) 145 { 146 strlcpy(p->errbuf, "Sending packets isn't supported on savefiles", 147 PCAP_ERRBUF_SIZE); 148 return (-1); 149 } 150 151 /* 152 * Set direction flag: Which packets do we accept on a forwarding 153 * single device? IN, OUT or both? 154 */ 155 static int 156 sf_setdirection(pcap_t *p, pcap_direction_t d) 157 { 158 snprintf(p->errbuf, sizeof(p->errbuf), 159 "Setting direction is not supported on savefiles"); 160 return (-1); 161 } 162 163 static void 164 sf_cleanup(pcap_t *p) 165 { 166 if (p->sf.rfile != stdin) 167 (void)fclose(p->sf.rfile); 168 if (p->buffer != NULL) 169 free(p->buffer); 170 pcap_freecode(&p->fcode); 171 } 172 173 pcap_t * 174 pcap_open_offline(const char *fname, char *errbuf) 175 { 176 FILE *fp; 177 pcap_t *p; 178 179 if (fname[0] == '-' && fname[1] == '\0') 180 { 181 fp = stdin; 182 #if defined(WIN32) || defined(MSDOS) 183 /* 184 * We're reading from the standard input, so put it in binary 185 * mode, as savefiles are binary files. 186 */ 187 SET_BINMODE(fp); 188 #endif 189 } 190 else { 191 #if !defined(WIN32) && !defined(MSDOS) 192 fp = fopen(fname, "r"); 193 #else 194 fp = fopen(fname, "rb"); 195 #endif 196 if (fp == NULL) { 197 snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", fname, 198 pcap_strerror(errno)); 199 return (NULL); 200 } 201 } 202 p = pcap_fopen_offline(fp, errbuf); 203 if (p == NULL) { 204 if (fp != stdin) 205 fclose(fp); 206 } 207 return (p); 208 } 209 210 #ifdef WIN32 211 pcap_t* pcap_hopen_offline(intptr_t osfd, char *errbuf) 212 { 213 int fd; 214 FILE *file; 215 216 fd = _open_osfhandle(osfd, _O_RDONLY); 217 if ( fd < 0 ) 218 { 219 snprintf(errbuf, PCAP_ERRBUF_SIZE, pcap_strerror(errno)); 220 return NULL; 221 } 222 223 file = _fdopen(fd, "rb"); 224 if ( file == NULL ) 225 { 226 snprintf(errbuf, PCAP_ERRBUF_SIZE, pcap_strerror(errno)); 227 return NULL; 228 } 229 230 return pcap_fopen_offline(file, errbuf); 231 } 232 #endif 233 234 static int (*check_headers[])(pcap_t *, bpf_u_int32, FILE *, char *) = { 235 pcap_check_header, 236 pcap_ng_check_header 237 }; 238 239 #define N_FILE_TYPES (sizeof check_headers / sizeof check_headers[0]) 240 241 #ifdef WIN32 242 static 243 #endif 244 pcap_t * 245 pcap_fopen_offline(FILE *fp, char *errbuf) 246 { 247 register pcap_t *p; 248 bpf_u_int32 magic; 249 size_t amt_read; 250 u_int i; 251 252 p = pcap_create_common("(savefile)", errbuf); 253 if (p == NULL) 254 return (NULL); 255 256 /* 257 * Read the first 4 bytes of the file; the network analyzer dump 258 * file formats we support (pcap and pcap-ng), and several other 259 * formats we might support in the future (such as snoop, DOS and 260 * Windows Sniffer, and Microsoft Network Monitor) all have magic 261 * numbers that are unique in their first 4 bytes. 262 */ 263 amt_read = fread((char *)&magic, 1, sizeof(magic), fp); 264 if (amt_read != sizeof(magic)) { 265 if (ferror(fp)) { 266 snprintf(errbuf, PCAP_ERRBUF_SIZE, 267 "error reading dump file: %s", 268 pcap_strerror(errno)); 269 } else { 270 snprintf(errbuf, PCAP_ERRBUF_SIZE, 271 "truncated dump file; tried to read %lu file header bytes, only got %lu", 272 (unsigned long)sizeof(magic), 273 (unsigned long)amt_read); 274 } 275 goto bad; 276 } 277 278 /* 279 * Try all file types. 280 */ 281 for (i = 0; i < N_FILE_TYPES; i++) { 282 switch ((*check_headers[i])(p, magic, fp, errbuf)) { 283 284 case -1: 285 /* 286 * Error trying to read the header. 287 */ 288 goto bad; 289 290 case 1: 291 /* 292 * Yup, that's it. 293 */ 294 goto found; 295 } 296 } 297 298 /* 299 * Well, who knows what this mess is.... 300 */ 301 snprintf(errbuf, PCAP_ERRBUF_SIZE, "unknown file format"); 302 goto bad; 303 304 found: 305 p->sf.rfile = fp; 306 307 #ifdef PCAP_FDDIPAD 308 /* Padding only needed for live capture fcode */ 309 p->fddipad = 0; 310 #endif 311 312 #if !defined(WIN32) && !defined(MSDOS) 313 /* 314 * You can do "select()" and "poll()" on plain files on most 315 * platforms, and should be able to do so on pipes. 316 * 317 * You can't do "select()" on anything other than sockets in 318 * Windows, so, on Win32 systems, we don't have "selectable_fd". 319 */ 320 p->selectable_fd = fileno(fp); 321 #endif 322 323 p->read_op = pcap_offline_read; 324 p->inject_op = sf_inject; 325 p->setfilter_op = install_bpf_program; 326 p->setdirection_op = sf_setdirection; 327 p->set_datalink_op = NULL; /* we don't support munging link-layer headers */ 328 p->getnonblock_op = sf_getnonblock; 329 p->setnonblock_op = sf_setnonblock; 330 p->stats_op = sf_stats; 331 #ifdef WIN32 332 p->setbuff_op = sf_setbuff; 333 p->setmode_op = sf_setmode; 334 p->setmintocopy_op = sf_setmintocopy; 335 #endif 336 p->cleanup_op = sf_cleanup; 337 p->activated = 1; 338 339 return (p); 340 bad: 341 free(p); 342 return (NULL); 343 } 344 345 /* 346 * Read packets from a capture file, and call the callback for each 347 * packet. 348 * If cnt > 0, return after 'cnt' packets, otherwise continue until eof. 349 */ 350 int 351 pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user) 352 { 353 struct bpf_insn *fcode; 354 int status = 0; 355 int n = 0; 356 u_char *data; 357 358 while (status == 0) { 359 struct pcap_pkthdr h; 360 361 /* 362 * Has "pcap_breakloop()" been called? 363 * If so, return immediately - if we haven't read any 364 * packets, clear the flag and return -2 to indicate 365 * that we were told to break out of the loop, otherwise 366 * leave the flag set, so that the *next* call will break 367 * out of the loop without having read any packets, and 368 * return the number of packets we've processed so far. 369 */ 370 if (p->break_loop) { 371 if (n == 0) { 372 p->break_loop = 0; 373 return (-2); 374 } else 375 return (n); 376 } 377 378 status = p->sf.next_packet_op(p, &h, &data); 379 if (status) { 380 if (status == 1) 381 return (0); 382 return (status); 383 } 384 385 if ((fcode = p->fcode.bf_insns) == NULL || 386 bpf_filter(fcode, data, h.len, h.caplen)) { 387 (*callback)(user, &h, data); 388 if (++n >= cnt && cnt > 0) 389 break; 390 } 391 } 392 /*XXX this breaks semantics tcpslice expects */ 393 return (n); 394 } 395