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/* ip.c - map hostnames */ |
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/* Copyright 1992 Mark Russell, University of Kent at Canterbury. |
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* |
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* You can do what you like with this source code as long as |
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* you don't try to make money out of it and you include an |
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* unaltered copy of this message (including the copyright). |
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*/ |
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char ukcprog_ip_sccsid[] = "$Id: ip.c,v 1.7 1995/12/20 15:31:00 mtr Exp $ UKC"; |
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#undef _POSIX_SOURCE |
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#ifndef MSDOS |
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#include <sys/types.h> |
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#else |
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#include <sys/tk_types.h> |
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#endif |
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#include <sys/socket.h> |
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#include <netinet/in.h> |
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#include <netdb.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <stdio.h> |
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#include "ukcprog.h" |
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/* Map a hostname to an IP address. The address is returned in network |
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* byte order. Return 0 for success, -1 and an error message on failure. |
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* |
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* If the hostname looks like an IP quad we convert that to an IP address. |
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*/ |
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int |
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get_host_addr(hostname, p_addr) |
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const char *hostname; |
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struct in_addr *p_addr; |
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{ |
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struct hostent *h; |
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int b3, b2, b1, b0; |
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char c; |
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if (sscanf(hostname, "%d.%d.%d.%d%c", &b3, &b2, &b1, &b0, &c) == 4) { |
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unsigned long val; |
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val = (b3 << 24) | (b2 << 16) | (b1 << 8) | b0; |
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p_addr->s_addr = htonl(val); |
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return 0; |
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} |
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if ((h = gethostbyname(hostname)) == NULL) { |
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errf("Can't find address of %s", hostname); |
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return -1; |
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} |
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if (h->h_addrtype != AF_INET) { |
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errf("%s has non-IP address (addrtype=%d)", |
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hostname, h->h_addrtype); |
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return -1; |
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} |
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memcpy((char *)p_addr, (char *)h->h_addr_list[0], sizeof(*p_addr)); |
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return 0; |
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} |
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/* Map a service name to a port number in network byte order. |
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* If the service name looks like a number we return that. |
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*/ |
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int |
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get_service_port(servname, p_port) |
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const char *servname; |
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int *p_port; |
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{ |
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struct servent *sp; |
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char *endstr; |
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unsigned short hport; |
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hport = strtol(servname, &endstr, 0); |
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if (endstr != servname && *endstr == '\0') { |
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*p_port = htons(hport); |
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return 0; |
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} |
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if ((sp = getservbyname(servname, "tcp")) == NULL) { |
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errf("Unknown service `%s'", servname); |
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return -1; |
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} |
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*p_port = sp->s_port; |
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return 0; |
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} |
