1 /* 2 * Copyright (c) 1983 Regents of the University of California. 3 * All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 */ 7 8 #if defined(LIBC_SCCS) && !defined(lint) 9 static char sccsid[] = "@(#)inet_addr.c 5.7 (Berkeley) 06/01/90"; 10 #endif /* LIBC_SCCS and not lint */ 11 12 #include <sys/types.h> 13 #include <ctype.h> 14 #include <netinet/in.h> 15 16 /* 17 * Internet address interpretation routine. 18 * All the network library routines call this 19 * routine to interpret entries in the data bases 20 * which are expected to be an address. 21 * The value returned is in network order. 22 */ 23 u_long 24 inet_addr(cp) 25 register char *cp; 26 { 27 register u_long val, base, n; 28 register char c; 29 u_long parts[4], *pp = parts; 30 31 again: 32 /* 33 * Collect number up to ``.''. 34 * Values are specified as for C: 35 * 0x=hex, 0=octal, other=decimal. 36 */ 37 val = 0; base = 10; 38 if (*cp == '0') { 39 if (*++cp == 'x' || *cp == 'X') 40 base = 16, cp++; 41 else 42 base = 8; 43 } 44 while (c = *cp) { 45 if (isdigit(c)) { 46 val = (val * base) + (c - '0'); 47 cp++; 48 continue; 49 } 50 if (base == 16 && isxdigit(c)) { 51 val = (val << 4) + (c + 10 - (islower(c) ? 'a' : 'A')); 52 cp++; 53 continue; 54 } 55 break; 56 } 57 if (*cp == '.') { 58 /* 59 * Internet format: 60 * a.b.c.d 61 * a.b.c (with c treated as 16-bits) 62 * a.b (with b treated as 24 bits) 63 */ 64 if (pp >= parts + 4) 65 return (INADDR_NONE); 66 *pp++ = val, cp++; 67 goto again; 68 } 69 /* 70 * Check for trailing characters. 71 */ 72 if (*cp && !isspace(*cp)) 73 return (INADDR_NONE); 74 *pp++ = val; 75 /* 76 * Concoct the address according to 77 * the number of parts specified. 78 */ 79 n = pp - parts; 80 switch (n) { 81 82 case 1: /* a -- 32 bits */ 83 val = parts[0]; 84 break; 85 86 case 2: /* a.b -- 8.24 bits */ 87 val = (parts[0] << 24) | (parts[1] & 0xffffff); 88 break; 89 90 case 3: /* a.b.c -- 8.8.16 bits */ 91 val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) | 92 (parts[2] & 0xffff); 93 break; 94 95 case 4: /* a.b.c.d -- 8.8.8.8 bits */ 96 val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) | 97 ((parts[2] & 0xff) << 8) | (parts[3] & 0xff); 98 break; 99 100 default: 101 return (INADDR_NONE); 102 } 103 val = htonl(val); 104 return (val); 105 } 106