1 /* 2 * Copyright (c) 1983, 1990 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 5.12 (Berkeley) 04/12/93"; 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, base, n; 45 register char c; 46 u_long parts[4], *pp = parts; 47 48 for (;;) { 49 /* 50 * Collect number up to ``.''. 51 * Values are specified as for C: 52 * 0x=hex, 0=octal, other=decimal. 53 */ 54 val = 0; base = 10; 55 if (*cp == '0') { 56 if (*++cp == 'x' || *cp == 'X') 57 base = 16, cp++; 58 else 59 base = 8; 60 } 61 while ((c = *cp) != '\0') { 62 if (isascii(c) && isdigit(c)) { 63 val = (val * base) + (c - '0'); 64 cp++; 65 continue; 66 } 67 if (base == 16 && isascii(c) && isxdigit(c)) { 68 val = (val << 4) + 69 (c + 10 - (islower(c) ? 'a' : 'A')); 70 cp++; 71 continue; 72 } 73 break; 74 } 75 if (*cp == '.') { 76 /* 77 * Internet format: 78 * a.b.c.d 79 * a.b.c (with c treated as 16-bits) 80 * a.b (with b treated as 24 bits) 81 */ 82 if (pp >= parts + 3 || val > 0xff) 83 return (0); 84 *pp++ = val, cp++; 85 } else 86 break; 87 } 88 /* 89 * Check for trailing characters. 90 */ 91 if (*cp && (!isascii(*cp) || !isspace(*cp))) 92 return (0); 93 /* 94 * Concoct the address according to 95 * the number of parts specified. 96 */ 97 n = pp - parts + 1; 98 switch (n) { 99 100 case 1: /* a -- 32 bits */ 101 break; 102 103 case 2: /* a.b -- 8.24 bits */ 104 if (val > 0xffffff) 105 return (0); 106 val |= parts[0] << 24; 107 break; 108 109 case 3: /* a.b.c -- 8.8.16 bits */ 110 if (val > 0xffff) 111 return (0); 112 val |= (parts[0] << 24) | (parts[1] << 16); 113 break; 114 115 case 4: /* a.b.c.d -- 8.8.8.8 bits */ 116 if (val > 0xff) 117 return (0); 118 val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8); 119 break; 120 } 121 if (addr) 122 addr->s_addr = htonl(val); 123 return (1); 124 } 125