The Tcpdump Group git mirrors - libpcap/blob - seltest.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 #ifndef lint
  23 static const char copyright[] =
  24     "@(#) Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000\n\
  25 The Regents of the University of California.  All rights reserved.\n";
  26 #endif
  27
  28 #include <pcap.h>
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <stdarg.h>
  33 #include <unistd.h>
  34 #include <errno.h>
  35 #include <sys/types.h>
  36
  37 char *program_name;
  38
  39 /* Forwards */
  40 static void printme(u_char *, const struct pcap_pkthdr *, const u_char *);
  41 static void usage(void) __attribute__((noreturn));
  42 static void error(const char *, ...);
  43 static void warning(const char *, ...);
  44 static char *copy_argv(char **);
  45
  46 static pcap_t *pd;
  47
  48 extern int optind;
  49 extern int opterr;
  50 extern char *optarg;
  51
  52 int
  53 main(int argc, char **argv)
  54 {
  55         register int op;
  56         bpf_u_int32 localnet, netmask;
  57         register char *cp, *cmdbuf, *device;
  58         int doselect, dotimeout, dononblock;
  59         struct bpf_program fcode;
  60         char ebuf[PCAP_ERRBUF_SIZE];
  61         int status;
  62
  63         device = NULL;
  64         doselect = 0;
  65         dotimeout = 0;
  66         dononblock = 0;
  67         if ((cp = strrchr(argv[0], '/')) != NULL)
  68                 program_name = cp + 1;
  69         else
  70                 program_name = argv[0];
  71
  72         opterr = 0;
  73         while ((op = getopt(argc, argv, "i:stn")) != -1)
  74                 switch (op) {
  75
  76                 case 'i':
  77                         device = optarg;
  78                         break;
  79
  80                 case 's':
  81                         doselect = 1;
  82                         break;
  83
  84                 case 't':
  85                         dotimeout = 1;
  86                         break;
  87
  88                 case 'n':
  89                         dononblock = 1;
  90                         break;
  91
  92                 default:
  93                         usage();
  94                         /* NOTREACHED */
  95                 }
  96
  97         if (device == NULL) {
  98                 device = pcap_lookupdev(ebuf);
  99                 if (device == NULL)
 100                         error("%s", ebuf);
 101         }
 102         *ebuf = '\0';
 103         pd = pcap_open_live(device, 65535, 0, 1000, ebuf);
 104         if (pd == NULL)
 105                 error("%s", ebuf);
 106         else if (*ebuf)
 107                 warning("%s", ebuf);
 108         if (pcap_lookupnet(device, &localnet, &netmask, ebuf) < 0) {
 109                 localnet = 0;
 110                 netmask = 0;
 111                 warning("%s", ebuf);
 112         }
 113         cmdbuf = copy_argv(&argv[optind]);
 114
 115         if (pcap_compile(pd, &fcode, cmdbuf, 1, netmask) < 0)
 116                 error("%s", pcap_geterr(pd));
 117
 118         if (pcap_setfilter(pd, &fcode) < 0)
 119                 error("%s", pcap_geterr(pd));
 120         if (pcap_get_selectable_fd(pd) == -1)
 121                 error("pcap_get_selectable_fd() fails");
 122         if (dononblock) {
 123                 if (pcap_setnonblock(pd, 1, ebuf) == -1)
 124                         error("pcap_setnonblock failed: %s", ebuf);
 125         }
 126         printf("Listening on %s\n", device);
 127         if (doselect) {
 128                 for (;;) {
 129                         int selectable_fd;
 130                         fd_set setread, setexcept;
 131                         struct timeval timeout;
 132
 133                         selectable_fd = pcap_get_selectable_fd(pd);
 134                         FD_ZERO(&setread);
 135                         FD_SET(selectable_fd, &setread);
 136                         FD_ZERO(&setexcept);
 137                         FD_SET(selectable_fd, &setexcept);
 138                         if (dotimeout) {
 139                                 timeout.tv_sec = 0;
 140                                 timeout.tv_usec = 1000;
 141                                 select(selectable_fd + 1, &setread, NULL,
 142                                     &setexcept, &timeout);
 143                         } else
 144                                 select(selectable_fd + 1, &setread, NULL,
 145                                     &setexcept, NULL);
 146                         if (FD_ISSET(selectable_fd, &setread))
 147                                 printf("Select says descriptor is readable\n");
 148                         else
 149                                 printf("Select doesn't say descriptor is readable\n");
 150                         if (FD_ISSET(selectable_fd, &setexcept))
 151                                 printf("Select says descriptor has exceptional condition\n");
 152                         else
 153                                 printf("Select doesn't say descriptor has exceptional condition\n");
 154                         status = pcap_dispatch(pd, -1, printme, NULL);
 155                         if (status < 0)
 156                                 break;
 157                         else if (status == 0)
 158                                 printf("No packets seen after select returns\n");
 159                         else
 160                                 printf("%d packets seen after select returns\n",
 161                                     status);
 162                 }
 163         } else
 164                 status = pcap_loop(pd, -1, printme, NULL);
 165         if (status == -2) {
 166                 /*
 167                  * We got interrupted, so perhaps we didn't
 168                  * manage to finish a line we were printing.
 169                  * Print an extra newline, just in case.
 170                  */
 171                 putchar('\n');
 172         }
 173         (void)fflush(stdout);
 174         if (status == -1) {
 175                 /*
 176                  * Error.  Report it.
 177                  */
 178                 (void)fprintf(stderr, "%s: pcap_loop: %s\n",
 179                     program_name, pcap_geterr(pd));
 180         }
 181         pcap_close(pd);
 182         exit(status == -1 ? 1 : 0);
 183 }
 184
 185 static void
 186 printme(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 187 {
 188         printf("Saw a packet\n");
 189 }
 190
 191 static void
 192 usage(void)
 193 {
 194         (void)fprintf(stderr, "Usage: %s [ -stn ] [ -i interface ] [expression]\n",
 195             program_name);
 196         exit(1);
 197 }
 198
 199 /* VARARGS */
 200 static void
 201 error(const char *fmt, ...)
 202 {
 203         va_list ap;
 204
 205         (void)fprintf(stderr, "%s: ", program_name);
 206         va_start(ap, fmt);
 207         (void)vfprintf(stderr, fmt, ap);
 208         va_end(ap);
 209         if (*fmt) {
 210                 fmt += strlen(fmt);
 211                 if (fmt[-1] != '\n')
 212                         (void)fputc('\n', stderr);
 213         }
 214         exit(1);
 215         /* NOTREACHED */
 216 }
 217
 218 /* VARARGS */
 219 static void
 220 warning(const char *fmt, ...)
 221 {
 222         va_list ap;
 223
 224         (void)fprintf(stderr, "%s: WARNING: ", program_name);
 225         va_start(ap, fmt);
 226         (void)vfprintf(stderr, fmt, ap);
 227         va_end(ap);
 228         if (*fmt) {
 229                 fmt += strlen(fmt);
 230                 if (fmt[-1] != '\n')
 231                         (void)fputc('\n', stderr);
 232         }
 233 }
 234
 235 /*
 236  * Copy arg vector into a new buffer, concatenating arguments with spaces.
 237  */
 238 static char *
 239 copy_argv(register char **argv)
 240 {
 241         register char **p;
 242         register u_int len = 0;
 243         char *buf;
 244         char *src, *dst;
 245
 246         p = argv;
 247         if (*p == 0)
 248                 return 0;
 249
 250         while (*p)
 251                 len += strlen(*p++) + 1;
 252
 253         buf = (char *)malloc(len);
 254         if (buf == NULL)
 255                 error("copy_argv: malloc");
 256
 257         p = argv;
 258         dst = buf;
 259         while ((src = *p++) != NULL) {
 260                 while ((*dst++ = *src++) != '\0')
 261                         ;
 262                 dst[-1] = ' ';
 263         }
 264         dst[-1] = '\0';
 265
 266         return buf;
 267 }