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