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 5.2 (Berkeley) 03/09/86"; 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 base = 8, cp++; 39 if (*cp == 'x' || *cp == 'X') 40 base = 16, cp++; 41 while (c = *cp) { 42 if (isdigit(c)) { 43 val = (val * base) + (c - '0'); 44 cp++; 45 continue; 46 } 47 if (base == 16 && isxdigit(c)) { 48 val = (val << 4) + (c + 10 - (islower(c) ? 'a' : 'A')); 49 cp++; 50 continue; 51 } 52 break; 53 } 54 if (*cp == '.') { 55 /* 56 * Internet format: 57 * a.b.c.d 58 * a.b.c (with c treated as 16-bits) 59 * a.b (with b treated as 24 bits) 60 */ 61 if (pp >= parts + 4) 62 return (-1); 63 *pp++ = val, cp++; 64 goto again; 65 } 66 /* 67 * Check for trailing characters. 68 */ 69 if (*cp && !isspace(*cp)) 70 return (-1); 71 *pp++ = val; 72 /* 73 * Concoct the address according to 74 * the number of parts specified. 75 */ 76 n = pp - parts; 77 switch (n) { 78 79 case 1: /* a -- 32 bits */ 80 val = parts[0]; 81 break; 82 83 case 2: /* a.b -- 8.24 bits */ 84 val = (parts[0] << 24) | (parts[1] & 0xffffff); 85 break; 86 87 case 3: /* a.b.c -- 8.8.16 bits */ 88 val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) | 89 (parts[2] & 0xffff); 90 break; 91 92 case 4: /* a.b.c.d -- 8.8.8.8 bits */ 93 val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) | 94 ((parts[2] & 0xff) << 8) | (parts[3] & 0xff); 95 break; 96 97 default: 98 return (-1); 99 } 100 val = htonl(val); 101 return (val); 102 } 103