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arping 2.21

    1: /* arping/src/unix.c
    2:  *
    3:  *  Copyright (C) 2000-2011 Thomas Habets <thomas@habets.se>
    4:  *
    5:  *  This program is free software; you can redistribute it and/or modify
    6:  *  it under the terms of the GNU General Public License as published by
    7:  *  the Free Software Foundation; either version 2 of the License, or
    8:  *  (at your option) any later version.
    9:  *
   10:  *  This program is distributed in the hope that it will be useful,
   11:  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   12:  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   13:  *  GNU General Public License for more details.
   14:  *
   15:  *  You should have received a copy of the GNU General Public License along
   16:  *  with this program; if not, write to the Free Software Foundation, Inc.,
   17:  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
   18:  */
   19: #if HAVE_CONFIG_H
   20: #include "config.h"
   21: #endif
   22: 
   23: #include <errno.h>
   24: #include <signal.h>
   25: #include <string.h>
   26: 
   27: #if HAVE_SYS_SOCKET_H
   28: #include <sys/socket.h>
   29: #endif
   30: 
   31: #if HAVE_NETINET_IN_H
   32: #include <netinet/in.h>
   33: #endif
   34: 
   35: #include <pcap.h>
   36: 
   37: #include "arping.h"
   38: 
   39: #define UNUSED(x) (void)(x)
   40: 
   41: /**
   42:  * Fall back on getting device name from pcap.
   43:  */
   44: const char *
   45: arping_lookupdev_default(uint32_t srcip, uint32_t dstip, char *ebuf)
   46: {
   47: #ifdef HAVE_PCAP_FINDALLDEVS
   48:         UNUSED(srcip);
   49:         pcap_if_t *ifs = NULL;
   50:         int rc = pcap_findalldevs(&ifs, ebuf);
   51:         if (rc) {
   52:                 return NULL;
   53:         }
   54: 
   55:         pcap_if_t *t;
   56:         char* ifname = NULL;
   57:         for (t = ifs; !ifname && t; t = t->next) {
   58: #ifdef PCAP_IF_LOOPBACK
   59:                 if (t->flags & PCAP_IF_LOOPBACK) {
   60:                         continue;
   61:                 }
   62: #endif
   63: #ifdef PCAP_IF_UP
   64:                 if (!(t->flags & PCAP_IF_UP)) {
   65:                         continue;
   66:                 }
   67: #endif
   68: 
   69:                 // This code is only called when using -F, which is "don't try
   70:                 // to be smart". If we wanted to be smart we would have used
   71:                 // findif_*.c.
   72:                 if (1) {
   73:                         ifname = strdup(t->name); // Memory leak.
   74:                         break;
   75:                 }
   76: 
   77:                 // UNREACHABLE
   78:                 pcap_addr_t *a;
   79:                 for (a = t->addresses; !ifname && a; a = a->next) {
   80:                         if (a->addr->sa_family != AF_INET) {
   81:                                 continue;
   82:                         }
   83:                         const struct sockaddr_in* sa = (struct sockaddr_in*)a->addr;
   84:                         const struct sockaddr_in* smask = (struct sockaddr_in*)a->netmask;
   85:                         const uint32_t addr = sa->sin_addr.s_addr;
   86:                         const uint32_t mask = smask->sin_addr.s_addr;
   87:                         if ((addr & mask) != (dstip & mask)) {
   88:                                 // Not optimal: memory leak.
   89:                                 ifname = strdup(t->name);
   90:                         }
   91:                 }
   92:         }
   93:         pcap_freealldevs(ifs);
   94:         return ifname;
   95: #else
   96:         UNUSED(srcip);
   97:         UNUSED(dstip);
   98:         return pcap_lookupdev(ebuf);
   99: #endif
  100: }
  101: 
  102: /**
  103:  *
  104:  */
  105: void
  106: do_signal_init()
  107: {
  108:         if (SIG_ERR == signal(SIGINT, sigint)) {
  109:                 fprintf(stderr, "arping: failed to set SIGINT handler: %s\n",
  110:                         strerror(errno));
  111:         }
  112: }
  113: /* ---- Emacs Variables ----
  114:  * Local Variables:
  115:  * c-basic-offset: 8
  116:  * indent-tabs-mode: nil
  117:  * End:
  118:  */