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/*
* Guillaume Cottenceau (gc)
*
* Copyright 2000 Mandriva
*
* This software may be freely redistributed under the terms of the GNU
* public license.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
/*
* Portions from Erik Troan (ewt@redhat.com)
*
* Copyright 1996 Red Hat Software
*
*/
#include <stdlib.h>
// dietlibc can do hostname lookup, whereas glibc can't when linked statically :-(
#if defined(__dietlibc__)
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <netdb.h>
#include <sys/socket.h>
#include <resolv.h>
#include "network.h"
#include "log.h"
#include "dns.h"
int mygethostbyname(char * name, struct in_addr * addr)
{
struct hostent * h;
/* prevent from timeouts */
if (_res.nscount == 0)
return -1;
h = gethostbyname(name);
if (!h && domain) {
// gethostbyname from dietlibc doesn't support domain handling
char fully_qualified[500];
sprintf(fully_qualified, "%s.%s", name, domain);
h = gethostbyname(fully_qualified);
}
if (h && h->h_addr_list && (h->h_addr_list)[0]) {
memcpy(addr, (h->h_addr_list)[0], sizeof(*addr));
log_message("is-at: %s", inet_ntoa(*addr));
return 0;
}
log_message("unknown host %s", name);
return -1;
}
char * mygethostbyaddr(char * ipnum)
{
struct in_addr in;
struct hostent * host;
/* prevent from timeouts */
if (_res.nscount == 0)
return NULL;
if (!inet_aton(ipnum, &in))
return NULL;
host = gethostbyaddr(&(in.s_addr), sizeof(in.s_addr) /* INADDRSZ */, AF_INET);
if (host && host->h_name)
return host->h_name;
return NULL;
}
#elif defined(__GLIBC__)
#include <alloca.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <resolv.h>
#include <arpa/nameser.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <string.h>
#include "log.h"
#include "dns.h"
/* This is dumb, but glibc doesn't like to do hostname lookups w/o libc.so */
union dns_response {
HEADER hdr;
u_char buf[PACKETSZ];
} ;
static int do_query(char * query, int queryType, char ** domainName, struct in_addr * ipNum)
{
int len, ancount, type;
u_char * data, * end;
char name[MAXDNAME];
union dns_response response;
#ifdef __sparc__
/* from jj: */
/* We have to wait till ethernet negotiation is done */
_res.retry = 3;
#else
_res.retry = 2;
#endif
len = res_search(query, C_IN, queryType, (void *) &response, sizeof(response));
if (len <= 0)
return -1;
if (ntohs(response.hdr.rcode) != NOERROR)
return -1;
ancount = ntohs(response.hdr.ancount);
if (ancount < 1)
return -1;
data = response.buf + sizeof(HEADER);
end = response.buf + len;
/* skip the question */
data += dn_skipname(data, end) + QFIXEDSZ;
/* parse the answer(s) */
while (--ancount >= 0 && data < end) {
/* skip the domain name portion of the RR record */
data += dn_skipname(data, end);
/* get RR information */
GETSHORT(type, data);
data += INT16SZ; /* skipp class */
data += INT32SZ; /* skipp TTL */
GETSHORT(len, data);
if (type == T_PTR) {
/* we got a pointer */
len = dn_expand(response.buf, end, data, name, sizeof(name));
if (len <= 0) return -1;
if (queryType == T_PTR && domainName) {
/* we wanted a pointer */
*domainName = malloc(strlen(name) + 1);
strcpy(*domainName, name);
return 0;
}
} else if (type == T_A) {
/* we got an address */
if (queryType == T_A && ipNum) {
/* we wanted an address */
memcpy(ipNum, data, sizeof(*ipNum));
return 0;
}
}
/* move ahead to next RR */
data += len;
}
return -1;
}
char * mygethostbyaddr(char * ipnum) {
int rc;
char * result;
char * strbuf;
char * chptr;
char * splits[4];
int i;
_res.retry = 1;
strbuf = alloca(strlen(ipnum) + 1);
strcpy(strbuf, ipnum);
ipnum = alloca(strlen(strbuf) + 20);
for (i = 0; i < 4; i++) {
chptr = strbuf;
while (*chptr && *chptr != '.')
chptr++;
*chptr = '\0';
if (chptr - strbuf > 3) return NULL;
splits[i] = strbuf;
strbuf = chptr + 1;
}
sprintf(ipnum, "%s.%s.%s.%s.in-addr.arpa", splits[3], splits[2], splits[1], splits[0]);
rc = do_query(ipnum, T_PTR, &result, NULL);
if (rc)
return NULL;
else
return result;
}
int mygethostbyname(char * name, struct in_addr * addr) {
int rc = do_query(name, T_A, NULL, addr);
if (!rc)
log_message("is-at %s", inet_ntoa(*addr));
return rc;
}
#else
#error "Unsupported C library"
#endif
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