unix4lyfe git - darkstat/blob - localip.c

   1 /* darkstat 3
   2  * copyright (c) 2001-2011 Emil Mikulic.
   3  *
   4  * localip.c: determine local IPs of an 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 "bsd.h" /* for strlcpy */
  12 #include "config.h" /* for HAVE_IFADDRS_H */
  13 #include "conv.h"
  14 #include "err.h"
  15 #include "localip.h"
  16 #include "now.h"
  17
  18 #include <sys/socket.h>
  19 #include <net/if.h>
  20 #include <assert.h>
  21 #include <errno.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <time.h>
  25 #include <unistd.h>
  26
  27 #ifdef HAVE_IFADDRS_H
  28 # include <ifaddrs.h>
  29 #else
  30 # ifdef HAVE_SYS_SOCKIO_H
  31 #  include <sys/sockio.h> /* for SIOCGIFADDR, especially on Solaris */
  32 # endif
  33 # include <sys/ioctl.h>
  34 #endif
  35
  36 void localip_init(struct local_ips *ips) {
  37    ips->is_valid = 0;
  38    ips->last_update_mono = 0;
  39    ips->num_addrs = 0;
  40    ips->addrs = NULL;
  41 }
  42
  43 void localip_free(struct local_ips *ips) {
  44    if (ips->addrs != NULL)
  45       free(ips->addrs);
  46 }
  47
  48 static void add_ip(const char *iface, struct local_ips *ips,
  49                    int *index, struct addr *a) {
  50    if (ips->num_addrs <= *index) {
  51       /* Grow. */
  52       ips->addrs = xrealloc(ips->addrs, sizeof(*(ips->addrs)) * (*index + 1));
  53       ips->num_addrs++;
  54       assert(ips->num_addrs > *index);
  55       verbosef("interface '%s' gained new address %s", iface, addr_to_str(a));
  56    } else {
  57       /* Warn about changed address. */
  58       if (!addr_equal(ips->addrs + *index, a)) {
  59          static char before[INET6_ADDRSTRLEN];
  60          strncpy(before, addr_to_str(ips->addrs + *index), INET6_ADDRSTRLEN);
  61          verbosef("interface '%s' address %d/%d changed from %s to %s",
  62             iface, *index+1, ips->num_addrs, before, addr_to_str(a));
  63       }
  64    }
  65    ips->addrs[*index] = *a;
  66    (*index)++;
  67 }
  68
  69 /* Returns 0 on failure. */
  70 void localip_update(const char *iface, struct local_ips *ips) {
  71    struct addr a;
  72    int new_addrs = 0;
  73
  74    if (iface == NULL) {
  75       /* reading from capfile */
  76       ips->is_valid = 0;
  77       return;
  78    }
  79
  80    if (ips->last_update_mono == now_mono()) {
  81       /* Too soon, bail out. */
  82       return;
  83    }
  84    ips->last_update_mono = now_mono();
  85
  86 #ifdef HAVE_IFADDRS_H
  87    {
  88       struct ifaddrs *ifas, *ifa;
  89
  90       if (getifaddrs(&ifas) < 0)
  91          err(1, "getifaddrs() failed");
  92
  93       for (ifa=ifas; ifa; ifa=ifa->ifa_next) {
  94          if (strncmp(ifa->ifa_name, iface, IFNAMSIZ))
  95             continue;   /* Wrong interface. */
  96
  97          if (!ifa->ifa_addr)
  98             continue;   /* This can be NULL, e.g. for ppp0. */
  99
 100          if (ifa->ifa_addr->sa_family == AF_INET) {
 101             a.family = IPv4;
 102             a.ip.v4 = ((struct sockaddr_in *)ifa->ifa_addr)->sin_addr.s_addr;
 103             add_ip(iface, ips, &new_addrs, &a);
 104          } else if (ifa->ifa_addr->sa_family == AF_INET6) {
 105             struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)ifa->ifa_addr;
 106 # if 0
 107             if ( IN6_IS_ADDR_LINKLOCAL(&(sa6->sin6_addr))
 108                  || IN6_IS_ADDR_SITELOCAL(&(sa6->sin6_addr)) )
 109                continue;
 110 # endif
 111             a.family = IPv6;
 112             memcpy(&(a.ip.v6), &sa6->sin6_addr, sizeof(a.ip.v6));
 113             add_ip(iface, ips, &new_addrs, &a);
 114 # ifdef AF_PACKET
 115          } else if (ifa->ifa_addr->sa_family == AF_PACKET) {
 116             /* ignore */
 117 # endif
 118          } else
 119             verbosef("unknown sa_family=%d on interface '%s'",
 120                (int)ifa->ifa_addr->sa_family, iface);
 121       }
 122       freeifaddrs(ifas);
 123    }
 124 #else /* don't HAVE_IFADDRS_H */
 125    {
 126       int tmp = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
 127       struct ifreq ifr;
 128       struct sockaddr sa;
 129
 130       strlcpy(ifr.ifr_name, iface, IFNAMSIZ);
 131       ifr.ifr_addr.sa_family = AF_INET;
 132       if (ioctl(tmp, SIOCGIFADDR, &ifr) != -1) {
 133          sa = ifr.ifr_addr;
 134          a.family = IPv4;
 135          a.ip.v4 = ((struct sockaddr_in*)(&ifr.ifr_addr))->sin_addr.s_addr;
 136          add_ip(iface, ips, &new_addrs, &a);
 137       }
 138       close(tmp);
 139    }
 140 #endif
 141    if (new_addrs == 0) {
 142       if (ips->is_valid)
 143          verbosef("interface '%s' no longer has any addresses", iface);
 144       ips->is_valid = 0;
 145    } else {
 146       if (!ips->is_valid)
 147          verbosef("interface '%s' now has addresses", iface);
 148       ips->is_valid = 1;
 149       if (ips->num_addrs != new_addrs)
 150          verbosef("interface '%s' number of addresses decreased from %d to %d",
 151             iface, ips->num_addrs, new_addrs);
 152       ips->num_addrs = new_addrs;
 153    }
 154 }
 155
 156 int is_localip(const struct addr * const a,
 157                const struct local_ips * const ips) {
 158    int i;
 159
 160    for (i=0; i<ips->num_addrs; i++) {
 161       if (addr_equal(a, ips->addrs+i))
 162          return 1;
 163    }
 164    return 0;
 165 }
 166
 167 /* vim:set ts=3 sw=3 tw=80 et: */