ref: 6701679f3a011dc45a96343fc9c703999be72491
dir: /sys/src/libip/myipaddr.c/
#include <u.h> #include <libc.h> #include <ip.h> static uchar loopbacknet[IPaddrlen] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff, 127, 0, 0, 0 }; static uchar loopbackmask[IPaddrlen] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0, 0, 0 }; static uchar loopback6[IPaddrlen] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 }; // find first ip that isn't a friggin loopback or // link-local address. prefer v4 over v6. int myipaddr(uchar *ip, char *net) { Ipifc *nifc; Iplifc *lifc; static Ipifc *ifc; uchar mynet[IPaddrlen]; ipmove(ip, IPnoaddr); ifc = readipifc(net, ifc, -1); for(nifc = ifc; nifc != nil; nifc = nifc->next){ for(lifc = nifc->lifc; lifc != nil; lifc = lifc->next){ /* unspecified */ if(ipcmp(lifc->ip, IPnoaddr) == 0) continue; if(isv4(lifc->ip)){ /* ipv4 loopback */ maskip(lifc->ip, loopbackmask, mynet); if(ipcmp(mynet, loopbacknet) == 0) continue; ipmove(ip, lifc->ip); return 0; } /* already got a v6 address? */ if(ipcmp(ip, IPnoaddr) != 0) continue; /* ipv6 loopback */ if(ipcmp(lifc->ip, loopback6) == 0) continue; /* ipv6 linklocal */ if(ISIPV6LINKLOCAL(lifc->ip)) continue; /* save first v6 address */ ipmove(ip, lifc->ip); } } return ipcmp(ip, IPnoaddr) != 0 ? 0 : -1; }