101 lines
2.0 KiB
C
101 lines
2.0 KiB
C
#if !defined(lint) && defined(SCCSIDS)
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static char sccsid[] = "@(#)inet_addr.c 1.1 94/10/31 SMI"; /* from UCB 4.5 82/11/14 */
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#endif
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#include <sys/types.h>
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#include <ctype.h>
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#include <netinet/in.h>
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/*
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* Internet address interpretation routine.
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* All the network library routines call this
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* routine to interpret entries in the data bases
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* which are expected to be an address.
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* The value returned is in network order.
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*/
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u_long
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inet_addr(cp)
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register char *cp;
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{
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register u_long val, base, n;
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register char c;
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u_long parts[4], *pp = parts;
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again:
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/*
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* Collect number up to ``.''.
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* Values are specified as for C:
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* 0x=hex, 0=octal, other=decimal.
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*/
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val = 0; base = 10;
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if (*cp == '0') {
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if (*++cp == 'x' || *cp == 'X')
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base = 16, cp++;
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else
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base = 8;
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}
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while (c = *cp) {
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if (isdigit(c)) {
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if ((c - '0') >= base)
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break;
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val = (val * base) + (c - '0');
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cp++;
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continue;
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}
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if (base == 16 && isxdigit(c)) {
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val = (val << 4) + (c + 10 - (islower(c) ? 'a' : 'A'));
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cp++;
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continue;
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}
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break;
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}
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if (*cp == '.') {
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/*
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* Internet format:
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* a.b.c.d
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* a.b.c (with c treated as 16-bits)
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* a.b (with b treated as 24 bits)
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*/
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if (pp >= parts + 4)
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return (-1);
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*pp++ = val, cp++;
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goto again;
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}
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/*
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* Check for trailing characters.
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*/
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if (*cp && !isspace(*cp))
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return (-1);
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*pp++ = val;
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/*
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* Concoct the address according to
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* the number of parts specified.
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*/
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n = pp - parts;
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switch (n) {
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case 1: /* a -- 32 bits */
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val = parts[0];
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break;
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case 2: /* a.b -- 8.24 bits */
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val = (parts[0] << 24) | (parts[1] & 0xffffff);
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break;
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case 3: /* a.b.c -- 8.8.16 bits */
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val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) |
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(parts[2] & 0xffff);
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break;
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case 4: /* a.b.c.d -- 8.8.8.8 bits */
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val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) |
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((parts[2] & 0xff) << 8) | (parts[3] & 0xff);
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break;
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default:
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return (-1);
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}
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val = htonl(val);
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return (val);
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}
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