1 /* 2 * Copyright (c) 1993, 1994, 1995, 1996, 1997, 1998 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 the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the Computer Systems 16 * Engineering Group at Lawrence Berkeley Laboratory. 17 * 4. Neither the name of the University nor of the Laboratory may be used 18 * to endorse or promote products derived from this software without 19 * specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #ifndef lint 35 static const char rcsid[] = 36 "@(#) $Header: /tcpdump/master/libpcap/pcap.c,v 1.38 2001/12/29 21:55:32 guy Exp $ (LBL)"; 37 #endif 38 39 #ifdef HAVE_CONFIG_H 40 #include "config.h" 41 #endif 42 43 #include <sys/types.h> 44 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include <unistd.h> 49 #include <fcntl.h> 50 #include <errno.h> 51 52 #ifdef HAVE_OS_PROTO_H 53 #include "os-proto.h" 54 #endif 55 56 #include "pcap-int.h" 57 58 int 59 pcap_dispatch(pcap_t *p, int cnt, pcap_handler callback, u_char *user) 60 { 61 62 if (p->sf.rfile != NULL) 63 return (pcap_offline_read(p, cnt, callback, user)); 64 return (pcap_read(p, cnt, callback, user)); 65 } 66 67 int 68 pcap_loop(pcap_t *p, int cnt, pcap_handler callback, u_char *user) 69 { 70 register int n; 71 72 for (;;) { 73 if (p->sf.rfile != NULL) 74 n = pcap_offline_read(p, cnt, callback, user); 75 else { 76 /* 77 * XXX keep reading until we get something 78 * (or an error occurs) 79 */ 80 do { 81 n = pcap_read(p, cnt, callback, user); 82 } while (n == 0); 83 } 84 if (n <= 0) 85 return (n); 86 if (cnt > 0) { 87 cnt -= n; 88 if (cnt <= 0) 89 return (0); 90 } 91 } 92 } 93 94 struct singleton { 95 struct pcap_pkthdr *hdr; 96 const u_char *pkt; 97 }; 98 99 100 static void 101 pcap_oneshot(u_char *userData, const struct pcap_pkthdr *h, const u_char *pkt) 102 { 103 struct singleton *sp = (struct singleton *)userData; 104 *sp->hdr = *h; 105 sp->pkt = pkt; 106 } 107 108 const u_char * 109 pcap_next(pcap_t *p, struct pcap_pkthdr *h) 110 { 111 struct singleton s; 112 113 s.hdr = h; 114 if (pcap_dispatch(p, 1, pcap_oneshot, (u_char*)&s) <= 0) 115 return (0); 116 return (s.pkt); 117 } 118 119 int 120 pcap_datalink(pcap_t *p) 121 { 122 return (p->linktype); 123 } 124 125 int 126 pcap_snapshot(pcap_t *p) 127 { 128 return (p->snapshot); 129 } 130 131 int 132 pcap_is_swapped(pcap_t *p) 133 { 134 return (p->sf.swapped); 135 } 136 137 int 138 pcap_major_version(pcap_t *p) 139 { 140 return (p->sf.version_major); 141 } 142 143 int 144 pcap_minor_version(pcap_t *p) 145 { 146 return (p->sf.version_minor); 147 } 148 149 FILE * 150 pcap_file(pcap_t *p) 151 { 152 return (p->sf.rfile); 153 } 154 155 int 156 pcap_fileno(pcap_t *p) 157 { 158 return (p->fd); 159 } 160 161 void 162 pcap_perror(pcap_t *p, char *prefix) 163 { 164 fprintf(stderr, "%s: %s\n", prefix, p->errbuf); 165 } 166 167 char * 168 pcap_geterr(pcap_t *p) 169 { 170 return (p->errbuf); 171 } 172 173 /* 174 * NOTE: in the future, these may need to call platform-dependent routines, 175 * e.g. on platforms with memory-mapped packet-capture mechanisms where 176 * "pcap_read()" uses "select()" or "poll()" to wait for packets to arrive. 177 */ 178 int 179 pcap_getnonblock(pcap_t *p, char *errbuf) 180 { 181 int fdflags; 182 183 if (p->sf.rfile != NULL) { 184 /* 185 * This is a savefile, not a live capture file, so 186 * never say it's in non-blocking mode. 187 */ 188 return (0); 189 } 190 fdflags = fcntl(p->fd, F_GETFL, 0); 191 if (fdflags == -1) { 192 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "F_GETFL: %s", 193 pcap_strerror(errno)); 194 return (-1); 195 } 196 if (fdflags & O_NONBLOCK) 197 return (1); 198 else 199 return (0); 200 } 201 202 int 203 pcap_setnonblock(pcap_t *p, int nonblock, char *errbuf) 204 { 205 int fdflags; 206 207 if (p->sf.rfile != NULL) { 208 /* 209 * This is a savefile, not a live capture file, so 210 * ignore requests to put it in non-blocking mode. 211 */ 212 return (0); 213 } 214 fdflags = fcntl(p->fd, F_GETFL, 0); 215 if (fdflags == -1) { 216 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "F_GETFL: %s", 217 pcap_strerror(errno)); 218 return (-1); 219 } 220 if (nonblock) 221 fdflags |= O_NONBLOCK; 222 else 223 fdflags &= ~O_NONBLOCK; 224 if (fcntl(p->fd, F_SETFL, fdflags) == -1) { 225 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "F_SETFL: %s", 226 pcap_strerror(errno)); 227 return (-1); 228 } 229 return (0); 230 } 231 232 /* 233 * Not all systems have strerror(). 234 */ 235 char * 236 pcap_strerror(int errnum) 237 { 238 #ifdef HAVE_STRERROR 239 return (strerror(errnum)); 240 #else 241 extern int sys_nerr; 242 extern const char *const sys_errlist[]; 243 static char ebuf[20]; 244 245 if ((unsigned int)errnum < sys_nerr) 246 return ((char *)sys_errlist[errnum]); 247 (void)snprintf(ebuf, sizeof ebuf, "Unknown error: %d", errnum); 248 return(ebuf); 249 #endif 250 } 251 252 pcap_t * 253 pcap_open_dead(int linktype, int snaplen) 254 { 255 pcap_t *p; 256 257 p = malloc(sizeof(*p)); 258 if (p == NULL) 259 return NULL; 260 memset (p, 0, sizeof(*p)); 261 p->fd = -1; 262 p->snapshot = snaplen; 263 p->linktype = linktype; 264 return p; 265 } 266 267 void 268 pcap_close(pcap_t *p) 269 { 270 /*XXX*/ 271 if (p->fd >= 0) { 272 #ifdef linux 273 pcap_close_linux(p); 274 #endif 275 close(p->fd); 276 } 277 if (p->sf.rfile != NULL) { 278 if (p->sf.rfile != stdin) 279 (void)fclose(p->sf.rfile); 280 if (p->sf.base != NULL) 281 free(p->sf.base); 282 } else if (p->buffer != NULL) 283 free(p->buffer); 284 285 pcap_freecode(&p->fcode); 286 free(p); 287 } 288