1 /* 2 * Copyright (c) 1983 Regents of the University of California. 3 * All rights reserved. The Berkeley software License Agreement 4 * specifies the terms and conditions for redistribution. 5 */ 6 7 #if defined(LIBC_SCCS) && !defined(lint) 8 static char sccsid[] = "@(#)inet_addr.c 5.3 (Berkeley) 06/03/87"; 9 #endif LIBC_SCCS and not lint 10 11 #include <sys/types.h> 12 #include <ctype.h> 13 #include <netinet/in.h> 14 15 /* 16 * Internet address interpretation routine. 17 * All the network library routines call this 18 * routine to interpret entries in the data bases 19 * which are expected to be an address. 20 * The value returned is in network order. 21 */ 22 u_long 23 inet_addr(cp) 24 register char *cp; 25 { 26 register u_long val, base, n; 27 register char c; 28 u_long parts[4], *pp = parts; 29 30 again: 31 /* 32 * Collect number up to ``.''. 33 * Values are specified as for C: 34 * 0x=hex, 0=octal, other=decimal. 35 */ 36 val = 0; base = 10; 37 if (*cp == '0') { 38 if (*++cp == 'x' || *cp == 'X') 39 base = 16, cp++; 40 else 41 base = 8; 42 } 43 while (c = *cp) { 44 if (isdigit(c)) { 45 val = (val * base) + (c - '0'); 46 cp++; 47 continue; 48 } 49 if (base == 16 && isxdigit(c)) { 50 val = (val << 4) + (c + 10 - (islower(c) ? 'a' : 'A')); 51 cp++; 52 continue; 53 } 54 break; 55 } 56 if (*cp == '.') { 57 /* 58 * Internet format: 59 * a.b.c.d 60 * a.b.c (with c treated as 16-bits) 61 * a.b (with b treated as 24 bits) 62 */ 63 if (pp >= parts + 4) 64 return (-1); 65 *pp++ = val, cp++; 66 goto again; 67 } 68 /* 69 * Check for trailing characters. 70 */ 71 if (*cp && !isspace(*cp)) 72 return (-1); 73 *pp++ = val; 74 /* 75 * Concoct the address according to 76 * the number of parts specified. 77 */ 78 n = pp - parts; 79 switch (n) { 80 81 case 1: /* a -- 32 bits */ 82 val = parts[0]; 83 break; 84 85 case 2: /* a.b -- 8.24 bits */ 86 val = (parts[0] << 24) | (parts[1] & 0xffffff); 87 break; 88 89 case 3: /* a.b.c -- 8.8.16 bits */ 90 val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) | 91 (parts[2] & 0xffff); 92 break; 93 94 case 4: /* a.b.c.d -- 8.8.8.8 bits */ 95 val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) | 96 ((parts[2] & 0xff) << 8) | (parts[3] & 0xff); 97 break; 98 99 default: 100 return (-1); 101 } 102 val = htonl(val); 103 return (val); 104 } 105