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/*
* Copyright (c) 1998 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <config.h>
#include "roken.h"
#undef roken_gethostbyname
#undef roken_gethostbyaddr
static struct sockaddr_in dns_addr;
static char *dns_req;
static int
make_address(const char *address, struct in_addr *ip)
{
if(inet_aton(address, ip) == 0){
/* try to resolve as hostname, it might work if the address we
are trying to lookup is local, for instance a web proxy */
struct hostent *he = gethostbyname(address);
if(he) {
unsigned char *p = (unsigned char*)he->h_addr;
ip->s_addr = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
} else {
return -1;
}
}
return 0;
}
static int
setup_int(const char *proxy_host, short proxy_port,
const char *dns_host, short dns_port,
const char *dns_path)
{
memset(&dns_addr, 0, sizeof(dns_addr));
if(dns_req)
free(dns_req);
dns_req = NULL;
if(proxy_host) {
if(make_address(proxy_host, &dns_addr.sin_addr) != 0)
return -1;
dns_addr.sin_port = htons(proxy_port);
if (asprintf(&dns_req, "http://%s:%d%s", dns_host, dns_port, dns_path) < 0)
return -1;
} else {
if(make_address(dns_host, &dns_addr.sin_addr) != 0)
return -1;
dns_addr.sin_port = htons(dns_port);
if (asprintf(&dns_req, "%s", dns_path) < 0)
return -1;
}
dns_addr.sin_family = AF_INET;
return 0;
}
static int
split_spec(const char *spec, char **host, int *port, char **path, int def_port)
{
char *p;
*host = strdup(spec);
if (*host == NULL)
return -1;
p = strchr(*host, ':');
if(p) {
*p++ = '\0';
if(sscanf(p, "%d", port) != 1)
*port = def_port;
} else
*port = def_port;
p = strchr(p ? p : *host, '/');
if(p) {
if(path) {
*path = strdup(p);
if (*path == NULL) {
free(*host);
*host = NULL;
return -1;
}
}
*p = '\0';
}else
if(path)
*path = NULL;
return 0;
}
ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
roken_gethostby_setup(const char *proxy_spec, const char *dns_spec)
{
char *proxy_host = NULL;
int proxy_port = 0;
char *dns_host = NULL, *dns_path = NULL;
int dns_port;
int ret;
ret = split_spec(dns_spec, &dns_host, &dns_port, &dns_path, 80);
if(ret)
goto out;
if(proxy_spec) {
ret = split_spec(proxy_spec, &proxy_host, &proxy_port, NULL, 80);
if (ret)
goto out;
}
ret = setup_int(proxy_host, proxy_port, dns_host, dns_port, dns_path);
if (ret)
goto out;
out:
free(proxy_host);
free(dns_host);
free(dns_path);
return ret;
}
/* Try to lookup a name or an ip-address using http as transport
mechanism. See the end of this file for an example program. */
static struct hostent*
roken_gethostby(const char *hostname)
{
int s;
struct sockaddr_in addr;
char *request = NULL;
char buf[1024];
int offset = 0;
int n;
char *p, *foo;
size_t len;
if(dns_addr.sin_family == 0)
return NULL; /* no configured host */
addr = dns_addr;
if (asprintf(&request, "GET %s?%s HTTP/1.0\r\n\r\n", dns_req, hostname) < 0)
return NULL;
if(request == NULL)
return NULL;
s = socket(AF_INET, SOCK_STREAM, 0);
if(s < 0) {
free(request);
return NULL;
}
if(connect(s, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
close(s);
free(request);
return NULL;
}
len = strlen(request);
if(write(s, request, len) != (ssize_t)len) {
close(s);
free(request);
return NULL;
}
free(request);
while(1) {
n = read(s, buf + offset, sizeof(buf) - offset);
if(n <= 0)
break;
offset += n;
}
buf[offset] = '\0';
close(s);
p = strstr(buf, "\r\n\r\n"); /* find end of header */
if(p) p += 4;
else return NULL;
foo = NULL;
p = strtok_r(p, " \t\r\n", &foo);
if(p == NULL)
return NULL;
{
/* make a hostent to return */
#define MAX_ADDRS 16
static struct hostent he;
static char addrs[4 * MAX_ADDRS];
static char *addr_list[MAX_ADDRS + 1];
int num_addrs = 0;
he.h_name = p;
he.h_aliases = NULL;
he.h_addrtype = AF_INET;
he.h_length = 4;
while((p = strtok_r(NULL, " \t\r\n", &foo)) && num_addrs < MAX_ADDRS) {
struct in_addr ip;
inet_aton(p, &ip);
ip.s_addr = ntohl(ip.s_addr);
addr_list[num_addrs] = &addrs[num_addrs * 4];
addrs[num_addrs * 4 + 0] = (ip.s_addr >> 24) & 0xff;
addrs[num_addrs * 4 + 1] = (ip.s_addr >> 16) & 0xff;
addrs[num_addrs * 4 + 2] = (ip.s_addr >> 8) & 0xff;
addrs[num_addrs * 4 + 3] = (ip.s_addr >> 0) & 0xff;
addr_list[++num_addrs] = NULL;
}
he.h_addr_list = addr_list;
return &he;
}
}
ROKEN_LIB_FUNCTION struct hostent* ROKEN_LIB_CALL
roken_gethostbyname(const char *hostname)
{
struct hostent *he;
he = gethostbyname(hostname);
if(he)
return he;
return roken_gethostby(hostname);
}
ROKEN_LIB_FUNCTION struct hostent* ROKEN_LIB_CALL
roken_gethostbyaddr(const void *addr, size_t len, int type)
{
struct in_addr a;
const char *p;
struct hostent *he;
he = gethostbyaddr(addr, len, type);
if(he)
return he;
if(type != AF_INET || len != 4)
return NULL;
p = addr;
a.s_addr = htonl((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]);
return roken_gethostby(inet_ntoa(a));
}
#if 0
/* this program can be used as a cgi `script' to lookup names and
ip-addresses */
#include <stdio.h>
#include <stdlib.h>
#include <netdb.h>
#include <sys/param.h>
int
main(int argc, char **argv)
{
char *query = getenv("QUERY_STRING");
char host[MAXHOSTNAMELEN];
int i;
struct hostent *he;
printf("Content-type: text/plain\n\n");
if(query == NULL)
exit(0);
he = gethostbyname(query);
strncpy(host, he->h_name, sizeof(host));
host[sizeof(host) - 1] = '\0';
he = gethostbyaddr(he->h_addr, he->h_length, AF_INET);
printf("%s\n", he->h_name);
for(i = 0; he->h_addr_list[i]; i++) {
struct in_addr ip;
unsigned char *p = (unsigned char*)he->h_addr_list[i];
ip.s_addr = htonl((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]);
printf("%s\n", inet_ntoa(ip));
}
exit(0);
}
#endif
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