tparseip.c - plan9port - [fork] Plan 9 from user space
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       ---
       tparseip.c (2129B)
       ---
            1 #include <u.h>
            2 #include <libc.h>
            3 #include <ip.h>
            4 
            5 char*
            6 v4parseip(uchar *to, char *from)
            7 {
            8         int i;
            9         char *p;
           10 
           11         p = from;
           12         for(i = 0; i < 4 && *p; i++){
           13                 to[i] = strtoul(p, &p, 0);
           14                 if(*p == '.')
           15                         p++;
           16         }
           17         switch(CLASS(to)){
           18         case 0:        /* class A - 1 uchar net */
           19         case 1:
           20                 if(i == 3){
           21                         to[3] = to[2];
           22                         to[2] = to[1];
           23                         to[1] = 0;
           24                 } else if (i == 2){
           25                         to[3] = to[1];
           26                         to[1] = 0;
           27                 }
           28                 break;
           29         case 2:        /* class B - 2 uchar net */
           30                 if(i == 3){
           31                         to[3] = to[2];
           32                         to[2] = 0;
           33                 }
           34                 break;
           35         }
           36         return p;
           37 }
           38 
           39 ulong
           40 parseip(uchar *to, char *from)
           41 {
           42         int i, elipsis = 0, v4 = 1;
           43         ulong x;
           44         char *p, *op;
           45 
           46         memset(to, 0, IPaddrlen);
           47         p = from;
           48         for(i = 0; i < 16 && *p; i+=2){
           49                 op = p;
           50                 x = strtoul(p, &p, 16);
           51                 if(*p == '.' || (*p == 0 && i == 0)){
           52                         p = v4parseip(to+i, op);
           53                         i += 4;
           54                         break;
           55                 }
           56                 to[i] = x>>8;
           57                 to[i+1] = x;
           58                 if(*p == ':'){
           59                         v4 = 0;
           60                         if(*++p == ':'){
           61                                 elipsis = i+2;
           62                                 p++;
           63                         }
           64                 }
           65         }
           66         if(i < 16){
           67                 memmove(&to[elipsis+16-i], &to[elipsis], i-elipsis);
           68                 memset(&to[elipsis], 0, 16-i);
           69         }
           70         if(v4){
           71                 to[10] = to[11] = 0xff;
           72                 return nhgetl(to+12);
           73         } else
           74                 return 6;
           75 }
           76 
           77 /*
           78  *  hack to allow ip v4 masks to be entered in the old
           79  *  style
           80  */
           81 ulong
           82 parseipmask(uchar *to, char *from)
           83 {
           84         ulong x;
           85         int i;
           86         uchar *p;
           87 
           88         if(*from == '/'){
           89                 /* as a number of prefix bits */
           90                 i = atoi(from+1);
           91                 if(i < 0)
           92                         i = 0;
           93                 if(i > 128)
           94                         i = 128;
           95                 memset(to, 0, IPaddrlen);
           96                 for(p = to; i >= 8; i -= 8)
           97                         *p++ = 0xff;
           98                 if(i > 0)
           99                         *p = ~((1<<(8-i))-1);
          100                 x = nhgetl(to+IPv4off);
          101         } else {
          102                 /* as a straight bit mask */
          103                 x = parseip(to, from);
          104                 if(memcmp(to, v4prefix, IPv4off) == 0)
          105                         memset(to, 0xff, IPv4off);
          106         }
          107         return x;
          108 }
          109 
          110 /*
          111  *  parse a v4 ip address/mask in cidr format
          112  */
          113 char*
          114 v4parsecidr(uchar *addr, uchar *mask, char *from)
          115 {
          116         int i;
          117         char *p;
          118         uchar *a;
          119 
          120         p = v4parseip(addr, from);
          121 
          122         if(*p == '/'){
          123                 /* as a number of prefix bits */
          124                 i = strtoul(p+1, &p, 0);
          125                 if(i > 32)
          126                         i = 32;
          127                 memset(mask, 0, IPv4addrlen);
          128                 for(a = mask; i >= 8; i -= 8)
          129                         *a++ = 0xff;
          130                 if(i > 0)
          131                         *a = ~((1<<(8-i))-1);
          132         } else
          133                 memcpy(mask, defmask(addr), IPv4addrlen);
          134         return p;
          135 }