sys/src/libip/myipaddr.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <ip.h>
   4
   5 static uchar loopbacknet[IPaddrlen] = {
   6         0, 0, 0, 0,
   7         0, 0, 0, 0,
   8         0, 0, 0xff, 0xff,
   9         127, 0, 0, 0
  10 };
  11 static uchar loopbackmask[IPaddrlen] = {
  12         0xff, 0xff, 0xff, 0xff,
  13         0xff, 0xff, 0xff, 0xff,
  14         0xff, 0xff, 0xff, 0xff,
  15         0xff, 0, 0, 0
  16 };
  17 static uchar loopback6[IPaddrlen] = {
  18         0, 0, 0, 0,
  19         0, 0, 0, 0,
  20         0, 0, 0, 0,
  21         0, 0, 0, 1
  22 };
  23
  24 // find first ip that isn't a friggin loopback or
  25 // link-local address. prefer v4 over v6.
  26 int
  27 myipaddr(uchar *ip, char *net)
  28 {
  29         Ipifc *nifc;
  30         Iplifc *lifc;
  31         static Ipifc *ifc;
  32         uchar mynet[IPaddrlen];
  33
  34         ipmove(ip, IPnoaddr);
  35         ifc = readipifc(net, ifc, -1);
  36         for(nifc = ifc; nifc != nil; nifc = nifc->next){
  37                 for(lifc = nifc->lifc; lifc != nil; lifc = lifc->next){
  38                         /* unspecified */
  39                         if(ipcmp(lifc->ip, IPnoaddr) == 0)
  40                                 continue;
  41
  42                         if(isv4(lifc->ip)){
  43                                 /* ipv4 loopback */
  44                                 maskip(lifc->ip, loopbackmask, mynet);
  45                                 if(ipcmp(mynet, loopbacknet) == 0)
  46                                         continue;
  47
  48                                 ipmove(ip, lifc->ip);
  49                                 return 0;
  50                         }
  51
  52                         /* already got a v6 address? */
  53                         if(ipcmp(ip, IPnoaddr) != 0)
  54                                 continue;
  55
  56                         /* ipv6 loopback */
  57                         if(ipcmp(lifc->ip, loopback6) == 0)
  58                                 continue;
  59
  60                         /* ipv6 linklocal */
  61                         if(ISIPV6LINKLOCAL(lifc->ip))
  62                                 continue;
  63
  64                         /* save first v6 address */
  65                         ipmove(ip, lifc->ip);
  66                 }
  67         }
  68         return ipcmp(ip, IPnoaddr) != 0 ? 0 : -1;
  69 }