1 /* 2 * Copyright (c) 1983, 1990, 1993 3 * The Regents of the University of California. 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 8.1 (Berkeley) 06/17/93"; 10 #endif /* LIBC_SCCS and not lint */ 11 12 #include <sys/param.h> 13 #include <netinet/in.h> 14 #include <arpa/inet.h> 15 #include <ctype.h> 16 17 /* 18 * Ascii internet address interpretation routine. 19 * The value returned is in network order. 20 */ 21 u_long 22 inet_addr(cp) 23 register const char *cp; 24 { 25 struct in_addr val; 26 27 if (inet_aton(cp, &val)) 28 return (val.s_addr); 29 return (INADDR_NONE); 30 } 31 32 /* 33 * Check whether "cp" is a valid ascii representation 34 * of an Internet address and convert to a binary address. 35 * Returns 1 if the address is valid, 0 if not. 36 * This replaces inet_addr, the return value from which 37 * cannot distinguish between failure and a local broadcast address. 38 */ 39 int 40 inet_aton(cp, addr) 41 register const char *cp; 42 struct in_addr *addr; 43 { 44 register u_long val; 45 register int base, n; 46 register char c; 47 u_int parts[4]; 48 register u_int *pp = parts; 49 50 for (;;) { 51 /* 52 * Collect number up to ``.''. 53 * Values are specified as for C: 54 * 0x=hex, 0=octal, other=decimal. 55 */ 56 val = 0; base = 10; 57 if (*cp == '0') { 58 if (*++cp == 'x' || *cp == 'X') 59 base = 16, cp++; 60 else 61 base = 8; 62 } 63 while ((c = *cp) != '\0') { 64 if (isascii(c) && isdigit(c)) { 65 val = (val * base) + (c - '0'); 66 cp++; 67 continue; 68 } 69 if (base == 16 && isascii(c) && isxdigit(c)) { 70 val = (val << 4) + 71 (c + 10 - (islower(c) ? 'a' : 'A')); 72 cp++; 73 continue; 74 } 75 break; 76 } 77 if (*cp == '.') { 78 /* 79 * Internet format: 80 * a.b.c.d 81 * a.b.c (with c treated as 16-bits) 82 * a.b (with b treated as 24 bits) 83 */ 84 if (pp >= parts + 3 || val > 0xff) 85 return (0); 86 *pp++ = val, cp++; 87 } else 88 break; 89 } 90 /* 91 * Check for trailing characters. 92 */ 93 if (*cp && (!isascii(*cp) || !isspace(*cp))) 94 return (0); 95 /* 96 * Concoct the address according to 97 * the number of parts specified. 98 */ 99 n = pp - parts + 1; 100 switch (n) { 101 102 case 1: /* a -- 32 bits */ 103 break; 104 105 case 2: /* a.b -- 8.24 bits */ 106 if (val > 0xffffff) 107 return (0); 108 val |= parts[0] << 24; 109 break; 110 111 case 3: /* a.b.c -- 8.8.16 bits */ 112 if (val > 0xffff) 113 return (0); 114 val |= (parts[0] << 24) | (parts[1] << 16); 115 break; 116 117 case 4: /* a.b.c.d -- 8.8.8.8 bits */ 118 if (val > 0xff) 119 return (0); 120 val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8); 121 break; 122 } 123 if (addr) 124 addr->s_addr = htonl(val); 125 return (1); 126 } 127