2 * Copyright (c) 1983, 1990, 1993
3 * The Regents of the University of California. All rights reserved.
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6 * modification, are permitted provided that the following conditions
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13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
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38 #if defined(LIBC_SCCS) && !defined(lint)
39 static char sccsid[] = "@(#)inet_addr.c 8.1 (Berkeley) 6/17/93";
40 #endif /* LIBC_SCCS and not lint */
45 /* Include for MinGW only. Cygwin will have the latter. */
48 #include <sys/param.h>
49 #include <netinet/in.h>
50 #include <arpa/inet.h>
56 * Ascii internet address interpretation routine.
57 * The value returned is in network order.
60 inet_addr(const char *cp)
64 if (inet_aton(cp, &val))
71 /* We provide this prototype to avoid compiler warnings. If this ever
72 conflicts with a declaration in a system header file, we'll find
73 out, because we should include that header file here. */
74 int inet_aton (const char *cp, struct in_addr *addr);
77 * Check whether "cp" is a valid ascii representation
78 * of an Internet address and convert to a binary address.
79 * Returns 1 if the address is valid, 0 if not.
80 * This replaces inet_addr, the return value from which
81 * cannot distinguish between failure and a local broadcast address. */
83 inet_aton(const char *cp_arg, struct in_addr *addr)
85 register unsigned long val;
87 register unsigned char c;
88 register unsigned const char *cp = (unsigned const char *) cp_arg;
89 unsigned int parts[4];
90 register unsigned int *pp = parts;
94 * Collect number up to ``.''.
95 * Values are specified as for C:
96 * 0x=hex, 0=octal, other=decimal.
100 if (*++cp == 'x' || *cp == 'X')
105 while ((c = *cp) != '\0') {
106 if (isascii(c) && isdigit(c)) {
107 val = (val * base) + (c - '0');
111 if (base == 16 && isascii(c) && isxdigit(c)) {
113 (c + 10 - (islower(c) ? 'a' : 'A'));
123 * a.b.c (with c treated as 16-bits)
124 * a.b (with b treated as 24 bits)
126 if (pp >= parts + 3 || val > 0xff)
133 * Check for trailing characters.
135 if (*cp && (!isascii(*cp) || !isspace(*cp)))
138 * Concoct the address according to
139 * the number of parts specified.
144 case 1: /* a -- 32 bits */
147 case 2: /* a.b -- 8.24 bits */
150 val |= parts[0] << 24;
153 case 3: /* a.b.c -- 8.8.16 bits */
156 val |= (parts[0] << 24) | (parts[1] << 16);
159 case 4: /* a.b.c.d -- 8.8.8.8 bits */
162 val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
166 addr->s_addr = htonl(val);