1 /* 2 * Copyright (c) 1983 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that this notice is preserved and that due credit is given 7 * to the University of California at Berkeley. The name of the University 8 * may not be used to endorse or promote products derived from this 9 * software without specific prior written permission. This software 10 * is provided ``as is'' without express or implied warranty. 11 */ 12 13 #if defined(LIBC_SCCS) && !defined(lint) 14 static char sccsid[] = "@(#)inet_addr.c 5.5 (Berkeley) 03/07/88"; 15 #endif /* LIBC_SCCS and not lint */ 16 17 #include <sys/types.h> 18 #include <ctype.h> 19 #include <netinet/in.h> 20 21 /* 22 * Internet address interpretation routine. 23 * All the network library routines call this 24 * routine to interpret entries in the data bases 25 * which are expected to be an address. 26 * The value returned is in network order. 27 */ 28 u_long 29 inet_addr(cp) 30 register char *cp; 31 { 32 register u_long val, base, n; 33 register char c; 34 u_long parts[4], *pp = parts; 35 36 again: 37 /* 38 * Collect number up to ``.''. 39 * Values are specified as for C: 40 * 0x=hex, 0=octal, other=decimal. 41 */ 42 val = 0; base = 10; 43 if (*cp == '0') { 44 if (*++cp == 'x' || *cp == 'X') 45 base = 16, cp++; 46 else 47 base = 8; 48 } 49 while (c = *cp) { 50 if (isdigit(c)) { 51 val = (val * base) + (c - '0'); 52 cp++; 53 continue; 54 } 55 if (base == 16 && isxdigit(c)) { 56 val = (val << 4) + (c + 10 - (islower(c) ? 'a' : 'A')); 57 cp++; 58 continue; 59 } 60 break; 61 } 62 if (*cp == '.') { 63 /* 64 * Internet format: 65 * a.b.c.d 66 * a.b.c (with c treated as 16-bits) 67 * a.b (with b treated as 24 bits) 68 */ 69 if (pp >= parts + 4) 70 return (INADDR_NONE); 71 *pp++ = val, cp++; 72 goto again; 73 } 74 /* 75 * Check for trailing characters. 76 */ 77 if (*cp && !isspace(*cp)) 78 return (INADDR_NONE); 79 *pp++ = val; 80 /* 81 * Concoct the address according to 82 * the number of parts specified. 83 */ 84 n = pp - parts; 85 switch (n) { 86 87 case 1: /* a -- 32 bits */ 88 val = parts[0]; 89 break; 90 91 case 2: /* a.b -- 8.24 bits */ 92 val = (parts[0] << 24) | (parts[1] & 0xffffff); 93 break; 94 95 case 3: /* a.b.c -- 8.8.16 bits */ 96 val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) | 97 (parts[2] & 0xffff); 98 break; 99 100 case 4: /* a.b.c.d -- 8.8.8.8 bits */ 101 val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) | 102 ((parts[2] & 0xff) << 8) | (parts[3] & 0xff); 103 break; 104 105 default: 106 return (INADDR_NONE); 107 } 108 val = htonl(val); 109 return (val); 110 } 111