| 1 | /* inet_addr.c 4.4 82/10/07 */ |
| 2 | |
| 3 | #include <sys/types.h> |
| 4 | #include <ctype.h> |
| 5 | #include <net/in.h> |
| 6 | |
| 7 | /* |
| 8 | * Internet address interpretation routine. |
| 9 | * All the network library routines call this |
| 10 | * routine to interpret entries in the data bases |
| 11 | * which are expected to be an address. |
| 12 | * The value returned is in network order. |
| 13 | */ |
| 14 | u_long |
| 15 | inet_addr(cp) |
| 16 | register char *cp; |
| 17 | { |
| 18 | register u_long val, base, n; |
| 19 | register char c; |
| 20 | u_long parts[4], *pp = parts; |
| 21 | |
| 22 | again: |
| 23 | /* |
| 24 | * Collect number up to ``.''. |
| 25 | * Values are specified as for C: |
| 26 | * 0x=hex, 0=octal, other=decimal. |
| 27 | */ |
| 28 | val = 0; base = 10; |
| 29 | if (*cp == '0') |
| 30 | base = 8, cp++; |
| 31 | if (*cp == 'x' || *cp == 'X') |
| 32 | base = 16, cp++; |
| 33 | while (c = *cp) { |
| 34 | if (isdigit(c)) { |
| 35 | val = (val * base) + (c - '0'); |
| 36 | cp++; |
| 37 | continue; |
| 38 | } |
| 39 | if (base == 16 && isxdigit(c)) { |
| 40 | val = (val << 4) + (c + 10 - (islower(c) ? 'a' : 'A')); |
| 41 | cp++; |
| 42 | continue; |
| 43 | } |
| 44 | break; |
| 45 | } |
| 46 | if (*cp == '.') { |
| 47 | /* |
| 48 | * Internet format: |
| 49 | * a.b.c.d |
| 50 | * a.b.c (with c treated as 16-bits) |
| 51 | * a.b (with b treated as 24 bits) |
| 52 | */ |
| 53 | if (pp >= parts + 4) |
| 54 | return (-1); |
| 55 | *pp++ = val, cp++; |
| 56 | goto again; |
| 57 | } |
| 58 | /* |
| 59 | * Check for trailing characters. |
| 60 | */ |
| 61 | if (*cp && !isspace(*cp)) |
| 62 | return (-1); |
| 63 | *pp++ = val; |
| 64 | /* |
| 65 | * Concoct the address according to |
| 66 | * the number of parts specified. |
| 67 | */ |
| 68 | n = pp - parts; |
| 69 | switch (n) { |
| 70 | |
| 71 | case 1: /* a -- 32 bits */ |
| 72 | val = parts[0]; |
| 73 | break; |
| 74 | |
| 75 | case 2: /* a.b -- 8.24 bits */ |
| 76 | val = (parts[0] << 24) | (parts[1] & 0xffffff); |
| 77 | break; |
| 78 | |
| 79 | case 3: /* a.b.c -- 8.8.16 bits */ |
| 80 | val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) | |
| 81 | (parts[2] & 0xffff); |
| 82 | break; |
| 83 | |
| 84 | case 4: /* a.b.c.d -- 8.8.8.8 bits */ |
| 85 | val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) | |
| 86 | ((parts[2] & 0xff) << 8) | (parts[3] & 0xff); |
| 87 | break; |
| 88 | |
| 89 | default: |
| 90 | return (-1); |
| 91 | } |
| 92 | val = htonl(val); |
| 93 | return (val); |
| 94 | } |