The Tcpdump Group git mirrors - libpcap/blob - testprogs/selpolltest.c

   1 /*
   2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000
   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
  22 #include "varattrs.h"
  23
  24 #ifndef lint
  25 static const char copyright[] _U_ =
  26     "@(#) Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000\n\
  27 The Regents of the University of California.  All rights reserved.\n";
  28 #endif
  29
  30 /*
  31  * Tests how select() and poll() behave on the selectable file descriptor
  32  * for a pcap_t.
  33  *
  34  * This would be significantly different on Windows, as it'd test
  35  * how WaitForMultipleObjects() would work on the event handle for a
  36  * pcap_t.
  37  */
  38 #include <pcap.h>
  39 #include <stdio.h>
  40 #include <stdlib.h>
  41 #include <string.h>
  42 #include <stdarg.h>
  43 #include <unistd.h>
  44 #include <errno.h>
  45 #include <sys/types.h>
  46 #ifdef HAVE_SYS_SELECT_H
  47 #include <sys/select.h>
  48 #else
  49 #include <sys/time.h>   /* older UN*Xes */
  50 #endif
  51 #include <poll.h>
  52
  53 #include "pcap/funcattrs.h"
  54
  55 char *program_name;
  56
  57 /* Forwards */
  58 static void countme(u_char *, const struct pcap_pkthdr *, const u_char *);
  59 static void PCAP_NORETURN usage(void);
  60 static void PCAP_NORETURN error(const char *, ...) PCAP_PRINTFLIKE(1, 2);
  61 static void warning(const char *, ...) PCAP_PRINTFLIKE(1, 2);
  62 static char *copy_argv(char **);
  63
  64 static pcap_t *pd;
  65
  66 int
  67 main(int argc, char **argv)
  68 {
  69         register int op;
  70         bpf_u_int32 localnet, netmask;
  71         register char *cp, *cmdbuf, *device;
  72         int doselect, dopoll, dotimeout, dononblock;
  73         char *mechanism;
  74         struct bpf_program fcode;
  75         char ebuf[PCAP_ERRBUF_SIZE];
  76         pcap_if_t *devlist;
  77         int selectable_fd;
  78         struct timeval *required_timeout;
  79         int status;
  80         int packet_count;
  81
  82         device = NULL;
  83         doselect = 0;
  84         dopoll = 0;
  85         mechanism = NULL;
  86         dotimeout = 0;
  87         dononblock = 0;
  88         if ((cp = strrchr(argv[0], '/')) != NULL)
  89                 program_name = cp + 1;
  90         else
  91                 program_name = argv[0];
  92
  93         opterr = 0;
  94         while ((op = getopt(argc, argv, "i:sptn")) != -1) {
  95                 switch (op) {
  96
  97                 case 'i':
  98                         device = optarg;
  99                         break;
 100
 101                 case 's':
 102                         doselect = 1;
 103                         mechanism = "select() and pcap_dispatch()";
 104                         break;
 105
 106                 case 'p':
 107                         dopoll = 1;
 108                         mechanism = "poll() and pcap_dispatch()";
 109                         break;
 110
 111                 case 't':
 112                         dotimeout = 1;
 113                         break;
 114
 115                 case 'n':
 116                         dononblock = 1;
 117                         break;
 118
 119                 default:
 120                         usage();
 121                         /* NOTREACHED */
 122                 }
 123         }
 124
 125         if (doselect && dopoll) {
 126                 fprintf(stderr, "selpolltest: choose select (-s) or poll (-p), but not both\n");
 127                 return 1;
 128         }
 129         if (dotimeout && !doselect && !dopoll) {
 130                 fprintf(stderr, "selpolltest: timeout (-t) requires select (-s) or poll (-p)\n");
 131                 return 1;
 132         }
 133         if (device == NULL) {
 134                 if (pcap_findalldevs(&devlist, ebuf) == -1)
 135                         error("%s", ebuf);
 136                 if (devlist == NULL)
 137                         error("no interfaces available for capture");
 138                 device = strdup(devlist->name);
 139                 pcap_freealldevs(devlist);
 140         }
 141         *ebuf = '\0';
 142         pd = pcap_open_live(device, 65535, 0, 1000, ebuf);
 143         if (pd == NULL)
 144                 error("%s", ebuf);
 145         else if (*ebuf)
 146                 warning("%s", ebuf);
 147         if (pcap_lookupnet(device, &localnet, &netmask, ebuf) < 0) {
 148                 localnet = 0;
 149                 netmask = 0;
 150                 warning("%s", ebuf);
 151         }
 152         cmdbuf = copy_argv(&argv[optind]);
 153
 154         if (pcap_compile(pd, &fcode, cmdbuf, 1, netmask) < 0)
 155                 error("%s", pcap_geterr(pd));
 156         if (pcap_setfilter(pd, &fcode) < 0)
 157                 error("%s", pcap_geterr(pd));
 158
 159         if (doselect || dopoll) {
 160                 /*
 161                  * We need either an FD on which to do select()/poll()
 162                  * or, if there isn't one, a timeout to use in select()/
 163                  * poll().
 164                  */
 165                 selectable_fd = pcap_get_selectable_fd(pd);
 166                 if (selectable_fd == -1) {
 167                         printf("Listening on %s, using %s, with a timeout\n",
 168                             device, mechanism);
 169                         required_timeout = pcap_get_required_select_timeout(pd);
 170                         if (required_timeout == NULL)
 171                                 error("select()/poll() isn't supported on %s, even with a timeout",
 172                                     device);
 173
 174                         /*
 175                          * As we won't be notified by select() or poll()
 176                          * that a read can be done, we'll have to periodically
 177                          * try reading from the device every time the required
 178                          * timeout expires, and we don't want those attempts
 179                          * to block if nothing has arrived in that interval,
 180                          * so we want to force non-blocking mode.
 181                          */
 182                         dononblock = 1;
 183                 } else {
 184                         printf("Listening on %s, using %s\n", device,
 185                             mechanism);
 186                         required_timeout = NULL;
 187                 }
 188         } else
 189                 printf("Listening on %s, using pcap_dispatch()\n", device);
 190
 191         if (dononblock) {
 192                 if (pcap_setnonblock(pd, 1, ebuf) == -1)
 193                         error("pcap_setnonblock failed: %s", ebuf);
 194         }
 195         if (doselect) {
 196                 for (;;) {
 197                         fd_set setread, setexcept;
 198                         struct timeval seltimeout;
 199
 200                         FD_ZERO(&setread);
 201                         if (selectable_fd != -1) {
 202                                 FD_SET(selectable_fd, &setread);
 203                                 FD_ZERO(&setexcept);
 204                                 FD_SET(selectable_fd, &setexcept);
 205                         }
 206                         if (dotimeout) {
 207                                 seltimeout.tv_sec = 0;
 208                                 if (required_timeout != NULL &&
 209                                     required_timeout->tv_usec < 1000)
 210                                         seltimeout.tv_usec = required_timeout->tv_usec;
 211                                 else
 212                                         seltimeout.tv_usec = 1000;
 213                                 status = select(selectable_fd + 1, &setread,
 214                                     NULL, &setexcept, &seltimeout);
 215                         } else if (required_timeout != NULL) {
 216                                 seltimeout = *required_timeout;
 217                                 status = select(selectable_fd + 1, &setread,
 218                                     NULL, &setexcept, &seltimeout);
 219                         } else {
 220                                 status = select((selectable_fd == -1) ?
 221                                     0 : selectable_fd + 1, &setread,
 222                                     NULL, &setexcept, NULL);
 223                         }
 224                         if (status == -1) {
 225                                 printf("Select returns error (%s)\n",
 226                                     strerror(errno));
 227                         } else {
 228                                 if (selectable_fd == -1) {
 229                                         if (status != 0)
 230                                                 printf("Select returned a descriptor\n");
 231                                 } else {
 232                                         if (status == 0)
 233                                                 printf("Select timed out: ");
 234                                         else
 235                                                 printf("Select returned a descriptor: ");
 236                                         if (FD_ISSET(selectable_fd, &setread))
 237                                                 printf("readable, ");
 238                                         else
 239                                                 printf("not readable, ");
 240                                         if (FD_ISSET(selectable_fd, &setexcept))
 241                                                 printf("exceptional condition\n");
 242                                         else
 243                                                 printf("no exceptional condition\n");
 244                                 }
 245                                 packet_count = 0;
 246                                 status = pcap_dispatch(pd, -1, countme,
 247                                     (u_char *)&packet_count);
 248                                 if (status < 0)
 249                                         break;
 250                                 /*
 251                                  * Don't report this if we're using a
 252                                  * required timeout and we got no packets,
 253                                  * because that could be a very short timeout,
 254                                  * and we don't want to spam the user with
 255                                  * a ton of "no packets" reports.
 256                                  */
 257                                 if (status != 0 || packet_count != 0 ||
 258                                     required_timeout != NULL) {
 259                                         printf("%d packets seen, %d packets counted after select returns\n",
 260                                             status, packet_count);
 261                                 }
 262                         }
 263                 }
 264         } else if (dopoll) {
 265                 for (;;) {
 266                         struct pollfd fd;
 267                         int polltimeout;
 268
 269                         fd.fd = selectable_fd;
 270                         fd.events = POLLIN;
 271                         if (dotimeout)
 272                                 polltimeout = 1;
 273                         else if (required_timeout != NULL &&
 274                             required_timeout->tv_usec >= 1000)
 275                                 polltimeout = required_timeout->tv_usec/1000;
 276                         else
 277                                 polltimeout = -1;
 278                         status = poll(&fd, (selectable_fd == -1) ? 0 : 1, polltimeout);
 279                         if (status == -1) {
 280                                 printf("Poll returns error (%s)\n",
 281                                     strerror(errno));
 282                         } else {
 283                                 if (selectable_fd == -1) {
 284                                         if (status != 0)
 285                                                 printf("Poll returned a descriptor\n");
 286                                 } else {
 287                                         if (status == 0)
 288                                                 printf("Poll timed out\n");
 289                                         else {
 290                                                 printf("Poll returned a descriptor: ");
 291                                                 if (fd.revents & POLLIN)
 292                                                         printf("readable, ");
 293                                                 else
 294                                                         printf("not readable, ");
 295                                                 if (fd.revents & POLLERR)
 296                                                         printf("exceptional condition, ");
 297                                                 else
 298                                                         printf("no exceptional condition, ");
 299                                                 if (fd.revents & POLLHUP)
 300                                                         printf("disconnect, ");
 301                                                 else
 302                                                         printf("no disconnect, ");
 303                                                 if (fd.revents & POLLNVAL)
 304                                                         printf("invalid\n");
 305                                                 else
 306                                                         printf("not invalid\n");
 307                                         }
 308                                 }
 309                                 packet_count = 0;
 310                                 status = pcap_dispatch(pd, -1, countme,
 311                                     (u_char *)&packet_count);
 312                                 if (status < 0)
 313                                         break;
 314                                 /*
 315                                  * Don't report this if we're using a
 316                                  * required timeout and we got no packets,
 317                                  * because that could be a very short timeout,
 318                                  * and we don't want to spam the user with
 319                                  * a ton of "no packets" reports.
 320                                  */
 321                                 if (status != 0 || packet_count != 0 ||
 322                                     required_timeout != NULL) {
 323                                         printf("%d packets seen, %d packets counted after poll returns\n",
 324                                             status, packet_count);
 325                                 }
 326                         }
 327                 }
 328         } else {
 329                 for (;;) {
 330                         packet_count = 0;
 331                         status = pcap_dispatch(pd, -1, countme,
 332                             (u_char *)&packet_count);
 333                         if (status < 0)
 334                                 break;
 335                         printf("%d packets seen, %d packets counted after pcap_dispatch returns\n",
 336                             status, packet_count);
 337                 }
 338         }
 339         if (status == -2) {
 340                 /*
 341                  * We got interrupted, so perhaps we didn't
 342                  * manage to finish a line we were printing.
 343                  * Print an extra newline, just in case.
 344                  */
 345                 putchar('\n');
 346         }
 347         (void)fflush(stdout);
 348         if (status == -1) {
 349                 /*
 350                  * Error.  Report it.
 351                  */
 352                 (void)fprintf(stderr, "%s: pcap_loop: %s\n",
 353                     program_name, pcap_geterr(pd));
 354         }
 355         pcap_close(pd);
 356         exit(status == -1 ? 1 : 0);
 357 }
 358
 359 static void
 360 countme(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 361 {
 362         int *counterp = (int *)user;
 363
 364         (*counterp)++;
 365 }
 366
 367 static void
 368 usage(void)
 369 {
 370         (void)fprintf(stderr, "Usage: %s [ -sptn ] [ -i interface ] [expression]\n",
 371             program_name);
 372         exit(1);
 373 }
 374
 375 /* VARARGS */
 376 static void
 377 error(const char *fmt, ...)
 378 {
 379         va_list ap;
 380
 381         (void)fprintf(stderr, "%s: ", program_name);
 382         va_start(ap, fmt);
 383         (void)vfprintf(stderr, fmt, ap);
 384         va_end(ap);
 385         if (*fmt) {
 386                 fmt += strlen(fmt);
 387                 if (fmt[-1] != '\n')
 388                         (void)fputc('\n', stderr);
 389         }
 390         exit(1);
 391         /* NOTREACHED */
 392 }
 393
 394 /* VARARGS */
 395 static void
 396 warning(const char *fmt, ...)
 397 {
 398         va_list ap;
 399
 400         (void)fprintf(stderr, "%s: WARNING: ", program_name);
 401         va_start(ap, fmt);
 402         (void)vfprintf(stderr, fmt, ap);
 403         va_end(ap);
 404         if (*fmt) {
 405                 fmt += strlen(fmt);
 406                 if (fmt[-1] != '\n')
 407                         (void)fputc('\n', stderr);
 408         }
 409 }
 410
 411 /*
 412  * Copy arg vector into a new buffer, concatenating arguments with spaces.
 413  */
 414 static char *
 415 copy_argv(register char **argv)
 416 {
 417         register char **p;
 418         register u_int len = 0;
 419         char *buf;
 420         char *src, *dst;
 421
 422         p = argv;
 423         if (*p == 0)
 424                 return 0;
 425
 426         while (*p)
 427                 len += strlen(*p++) + 1;
 428
 429         buf = (char *)malloc(len);
 430         if (buf == NULL)
 431                 error("copy_argv: malloc");
 432
 433         p = argv;
 434         dst = buf;
 435         while ((src = *p++) != NULL) {
 436                 while ((*dst++ = *src++) != '\0')
 437                         ;
 438                 dst[-1] = ' ';
 439         }
 440         dst[-1] = '\0';
 441
 442         return buf;
 443 }