2 * Copyright (c) 1998 Kungliga Tekniska Högskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the Institute nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 RCSID("$Id: roken_gethostby.c,v 1.4 1999/12/02 16:58:52 joda Exp $");
43 #ifdef HAVE_ARPA_INET_H
44 #include <arpa/inet.h>
47 #undef roken_gethostbyname
48 #undef roken_gethostbyaddr
50 static struct sockaddr_in dns_addr;
54 make_address(const char *address, struct in_addr *ip)
56 if(inet_aton(address, ip) == 0){
57 /* try to resolve as hostname, it might work if the address we
58 are trying to lookup is local, for instance a web proxy */
59 struct hostent *he = gethostbyname(address);
61 unsigned char *p = (unsigned char*)he->h_addr;
62 ip->s_addr = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
71 setup_int(const char *proxy_host, short proxy_port,
72 const char *dns_host, short dns_port,
75 memset(&dns_addr, 0, sizeof(dns_addr));
79 if(make_address(proxy_host, &dns_addr.sin_addr) != 0)
81 dns_addr.sin_port = htons(proxy_port);
82 asprintf(&dns_req, "http://%s:%d%s", dns_host, dns_port, dns_path);
84 if(make_address(dns_host, &dns_addr.sin_addr) != 0)
86 dns_addr.sin_port = htons(dns_port);
87 asprintf(&dns_req, "%s", dns_path);
89 dns_addr.sin_family = AF_INET;
94 split_spec(const char *spec, char **host, int *port, char **path, int def_port)
98 p = strchr(*host, ':');
101 if(sscanf(p, "%d", port) != 1)
105 p = strchr(p ? p : *host, '/');
117 roken_gethostby_setup(const char *proxy_spec, const char *dns_spec)
119 char *proxy_host = NULL;
121 char *dns_host, *dns_path;
126 split_spec(dns_spec, &dns_host, &dns_port, &dns_path, 80);
130 split_spec(proxy_spec, &proxy_host, &proxy_port, NULL, 80);
131 ret = setup_int(proxy_host, proxy_port, dns_host, dns_port, dns_path);
140 /* Try to lookup a name or an ip-address using http as transport
141 mechanism. See the end of this file for an example program. */
142 static struct hostent*
143 roken_gethostby(const char *hostname)
146 struct sockaddr_in sin;
153 if(dns_addr.sin_family == 0)
154 return NULL; /* no configured host */
156 asprintf(&request, "GET %s?%s HTTP/1.0\r\n\r\n", dns_req, hostname);
159 s = socket(AF_INET, SOCK_STREAM, 0);
164 if(connect(s, (struct sockaddr*)&sin, sizeof(sin)) < 0) {
169 if(write(s, request, strlen(request)) != strlen(request)) {
176 n = read(s, buf + offset, sizeof(buf) - offset);
183 p = strstr(buf, "\r\n\r\n"); /* find end of header */
187 p = strtok_r(p, " \t\r\n", &foo);
191 /* make a hostent to return */
193 static struct hostent he;
194 static char addrs[4 * MAX_ADDRS];
195 static char *addr_list[MAX_ADDRS];
200 he.h_addrtype = AF_INET;
203 while((p = strtok_r(NULL, " \t\r\n", &foo)) && num_addrs < MAX_ADDRS) {
206 ip.s_addr = ntohl(ip.s_addr);
207 addr_list[num_addrs] = &addrs[num_addrs * 4];
208 addrs[num_addrs * 4 + 0] = (ip.s_addr >> 24) & 0xff;
209 addrs[num_addrs * 4 + 1] = (ip.s_addr >> 16) & 0xff;
210 addrs[num_addrs * 4 + 2] = (ip.s_addr >> 8) & 0xff;
211 addrs[num_addrs * 4 + 3] = (ip.s_addr >> 0) & 0xff;
212 addr_list[++num_addrs] = NULL;
214 he.h_addr_list = addr_list;
220 roken_gethostbyname(const char *hostname)
223 he = gethostbyname(hostname);
226 return roken_gethostby(hostname);
230 roken_gethostbyaddr(const void *addr, size_t len, int type)
235 he = gethostbyaddr(addr, len, type);
238 if(type != AF_INET || len != 4)
241 a.s_addr = htonl((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]);
242 return roken_gethostby(inet_ntoa(a));
247 /* this program can be used as a cgi `script' to lookup names and
253 #include <sys/param.h>
256 main(int argc, char **argv)
258 char *query = getenv("QUERY_STRING");
259 char host[MAXHOSTNAMELEN];
263 printf("Content-type: text/plain\n\n");
266 he = gethostbyname(query);
267 strncpy(host, he->h_name, sizeof(host));
268 host[sizeof(host) - 1] = '\0';
269 he = gethostbyaddr(he->h_addr, he->h_length, AF_INET);
270 printf("%s\n", he->h_name);
271 for(i = 0; he->h_addr_list[i]; i++) {
273 unsigned char *p = (unsigned char*)he->h_addr_list[i];
274 ip.s_addr = htonl((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]);
275 printf("%s\n", inet_ntoa(ip));