unix4lyfe git - darkstat/blob - localip.c

   1 /* darkstat 3
   2  * copyright (c) 2001-2011 Emil Mikulic.
   3  *
   4  * localip.c: determine local IP of our capture interface
   5  *
   6  * You may use, modify and redistribute this file under the terms of the
   7  * GNU General Public License version 2. (see COPYING.GPL)
   8  */
   9
  10 #include "addr.h"
  11 #include "config.h" /* for HAVE_IFADDRS_H */
  12 #include "conv.h" /* for strlcpy */
  13 #include "err.h"
  14 #include "localip.h"
  15
  16 #include <sys/socket.h>
  17 #include <net/if.h>
  18 #include <errno.h>
  19 #include <string.h>
  20 #include <unistd.h>
  21
  22 #ifdef HAVE_IFADDRS_H
  23 # include <ifaddrs.h>
  24 #else
  25 # ifdef HAVE_SYS_SOCKIO_H
  26 #  include <sys/sockio.h> /* for SIOCGIFADDR, especially on Solaris */
  27 # endif
  28 # include <sys/ioctl.h>
  29 #endif
  30
  31 static const char *iface = NULL;
  32 struct addr localip4, localip6;
  33 static struct addr last_localip4, last_localip6;
  34
  35 void
  36 localip_init(const char *interface)
  37 {
  38    iface = interface;
  39    localip_update();
  40 }
  41
  42 void
  43 localip_update(void)
  44 {
  45    /* defaults */
  46    localip4.family = IPv4;
  47    localip4.ip.v4 = 0;
  48
  49    localip6.family = IPv6;
  50    memset(&(localip6.ip.v6), 0, sizeof(localip6.ip.v6));
  51
  52    if (iface != NULL) {
  53       /* not reading from capfile */
  54 #ifdef HAVE_IFADDRS_H
  55       int got_v4 = 0, got_v6 = 0;
  56       struct ifaddrs *ifas, *ifa;
  57
  58       if (getifaddrs(&ifas) < 0)
  59          err(1, "can't get own IP address on interface \"%s\"", iface);
  60
  61       for (ifa = ifas; ifa; ifa = ifa->ifa_next) {
  62          if (got_v4 && got_v6)
  63             break;   /* Task is already complete. */
  64
  65          if (strncmp(ifa->ifa_name, iface, IFNAMSIZ))
  66             continue;   /* Wrong interface. */
  67
  68          /* The first IPv4 name is always functional. */
  69          if ((ifa->ifa_addr->sa_family == AF_INET) && !got_v4)
  70          {
  71             /* Good IPv4 address. */
  72             localip4.ip.v4 =
  73                ((struct sockaddr_in *)ifa->ifa_addr)->sin_addr.s_addr;
  74             got_v4 = 1;
  75             continue;
  76          }
  77
  78          /* IPv6 needs some obvious exceptions. */
  79          if ( ifa->ifa_addr->sa_family == AF_INET6 ) {
  80             struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *) ifa->ifa_addr;
  81
  82             if ( IN6_IS_ADDR_LINKLOCAL(&(sa6->sin6_addr))
  83                  || IN6_IS_ADDR_SITELOCAL(&(sa6->sin6_addr)) )
  84                continue;
  85
  86             /* Only standard IPv6 can reach this point. */
  87             memcpy(&(localip6.ip.v6), &sa6->sin6_addr, sizeof(localip6.ip.v6));
  88             got_v6 = 1;
  89          }
  90       }
  91
  92       freeifaddrs(ifas);
  93
  94       /* Report an error if IPv4 address could not be found. */
  95       if (!got_v4)
  96           err(1, "can't get own IPv4 address on interface \"%s\"", iface);
  97
  98 #else /* don't HAVE_IFADDRS_H */
  99
 100       int tmp = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
 101       struct ifreq ifr;
 102       struct sockaddr sa;
 103
 104       strlcpy(ifr.ifr_name, iface, IFNAMSIZ);
 105       ifr.ifr_addr.sa_family = AF_INET;
 106       if (ioctl(tmp, SIOCGIFADDR, &ifr) == -1) {
 107          if (errno == EADDRNOTAVAIL) {
 108             verbosef("lost local IP");
 109          } else
 110             err(1, "can't get own IP address on interface \"%s\"", iface);
 111       } else {
 112          /* success! */
 113          sa = ifr.ifr_addr;
 114          localip4.ip.v4 = ((struct sockaddr_in*)&sa)->sin_addr.s_addr;
 115       }
 116       close(tmp);
 117
 118 #endif
 119    }
 120
 121    if (!addr_equal(&last_localip4, &localip4)) {
 122       verbosef("localip4 update(%s) = %s", iface, addr_to_str(&localip4));
 123       last_localip4 = localip4;
 124    }
 125    if (!addr_equal(&last_localip6, &localip6)) {
 126       verbosef("localip6 update(%s) = %s", iface, addr_to_str(&localip6));
 127       last_localip6 = localip6;
 128    }
 129 }
 130
 131 /* vim:set ts=3 sw=3 tw=78 expandtab: */