1 : /*
2 : * Copyright (c) 1998 Kungliga Tekniska Högskolan
3 : * (Royal Institute of Technology, Stockholm, Sweden).
4 : * All rights reserved.
5 : *
6 : * Redistribution and use in source and binary forms, with or without
7 : * modification, are permitted provided that the following conditions
8 : * are met:
9 : *
10 : * 1. Redistributions of source code must retain the above copyright
11 : * notice, this list of conditions and the following disclaimer.
12 : *
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.
16 : *
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.
20 : *
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
31 : * SUCH DAMAGE.
32 : */
33 :
34 : #include <config.h>
35 :
36 : #include "roken.h"
37 :
38 : #undef roken_gethostbyname
39 : #undef roken_gethostbyaddr
40 :
41 : static struct sockaddr_in dns_addr;
42 : static char *dns_req;
43 :
44 : static int
45 : make_address(const char *address, struct in_addr *ip)
46 0 : {
47 0 : if(inet_aton(address, ip) == 0){
48 : /* try to resolve as hostname, it might work if the address we
49 : are trying to lookup is local, for instance a web proxy */
50 0 : struct hostent *he = gethostbyname(address);
51 0 : if(he) {
52 0 : unsigned char *p = (unsigned char*)he->h_addr;
53 0 : ip->s_addr = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
54 : } else {
55 0 : return -1;
56 : }
57 : }
58 0 : return 0;
59 : }
60 :
61 : static int
62 : setup_int(const char *proxy_host, short proxy_port,
63 : const char *dns_host, short dns_port,
64 : const char *dns_path)
65 0 : {
66 0 : memset(&dns_addr, 0, sizeof(dns_addr));
67 0 : if(dns_req)
68 0 : free(dns_req);
69 0 : if(proxy_host) {
70 0 : if(make_address(proxy_host, &dns_addr.sin_addr) != 0)
71 0 : return -1;
72 0 : dns_addr.sin_port = htons(proxy_port);
73 0 : asprintf(&dns_req, "http://%s:%d%s", dns_host, dns_port, dns_path);
74 : } else {
75 0 : if(make_address(dns_host, &dns_addr.sin_addr) != 0)
76 0 : return -1;
77 0 : dns_addr.sin_port = htons(dns_port);
78 0 : asprintf(&dns_req, "%s", dns_path);
79 : }
80 0 : dns_addr.sin_family = AF_INET;
81 0 : return 0;
82 : }
83 :
84 : static void
85 : split_spec(const char *spec, char **host, int *port, char **path, int def_port)
86 0 : {
87 : char *p;
88 0 : *host = strdup(spec);
89 0 : p = strchr(*host, ':');
90 0 : if(p) {
91 0 : *p++ = '\0';
92 0 : if(sscanf(p, "%d", port) != 1)
93 0 : *port = def_port;
94 : } else
95 0 : *port = def_port;
96 0 : p = strchr(p ? p : *host, '/');
97 0 : if(p) {
98 0 : if(path)
99 0 : *path = strdup(p);
100 0 : *p = '\0';
101 : }else
102 0 : if(path)
103 0 : *path = NULL;
104 0 : }
105 :
106 :
107 : ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
108 : roken_gethostby_setup(const char *proxy_spec, const char *dns_spec)
109 0 : {
110 0 : char *proxy_host = NULL;
111 0 : int proxy_port = 0;
112 : char *dns_host, *dns_path;
113 : int dns_port;
114 :
115 0 : int ret = -1;
116 :
117 0 : split_spec(dns_spec, &dns_host, &dns_port, &dns_path, 80);
118 0 : if(dns_path == NULL)
119 0 : goto out;
120 0 : if(proxy_spec)
121 0 : split_spec(proxy_spec, &proxy_host, &proxy_port, NULL, 80);
122 0 : ret = setup_int(proxy_host, proxy_port, dns_host, dns_port, dns_path);
123 0 : out:
124 0 : free(proxy_host);
125 0 : free(dns_host);
126 0 : free(dns_path);
127 0 : return ret;
128 : }
129 :
130 :
131 : /* Try to lookup a name or an ip-address using http as transport
132 : mechanism. See the end of this file for an example program. */
133 : static struct hostent*
134 : roken_gethostby(const char *hostname)
135 0 : {
136 : int s;
137 : struct sockaddr_in addr;
138 : char *request;
139 : char buf[1024];
140 0 : int offset = 0;
141 : int n;
142 : char *p, *foo;
143 :
144 0 : if(dns_addr.sin_family == 0)
145 0 : return NULL; /* no configured host */
146 0 : addr = dns_addr;
147 0 : asprintf(&request, "GET %s?%s HTTP/1.0\r\n\r\n", dns_req, hostname);
148 0 : if(request == NULL)
149 0 : return NULL;
150 0 : s = socket(AF_INET, SOCK_STREAM, 0);
151 0 : if(s < 0) {
152 0 : free(request);
153 0 : return NULL;
154 : }
155 0 : if(connect(s, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
156 0 : close(s);
157 0 : free(request);
158 0 : return NULL;
159 : }
160 0 : if(write(s, request, strlen(request)) != strlen(request)) {
161 0 : close(s);
162 0 : free(request);
163 0 : return NULL;
164 : }
165 0 : free(request);
166 : while(1) {
167 0 : n = read(s, buf + offset, sizeof(buf) - offset);
168 0 : if(n <= 0)
169 0 : break;
170 0 : offset += n;
171 0 : }
172 0 : buf[offset] = '\0';
173 0 : close(s);
174 0 : p = strstr(buf, "\r\n\r\n"); /* find end of header */
175 0 : if(p) p += 4;
176 0 : else return NULL;
177 0 : foo = NULL;
178 0 : p = strtok_r(p, " \t\r\n", &foo);
179 0 : if(p == NULL)
180 0 : return NULL;
181 : {
182 : /* make a hostent to return */
183 : #define MAX_ADDRS 16
184 : static struct hostent he;
185 : static char addrs[4 * MAX_ADDRS];
186 : static char *addr_list[MAX_ADDRS + 1];
187 0 : int num_addrs = 0;
188 :
189 0 : he.h_name = p;
190 0 : he.h_aliases = NULL;
191 0 : he.h_addrtype = AF_INET;
192 0 : he.h_length = 4;
193 :
194 0 : while((p = strtok_r(NULL, " \t\r\n", &foo)) && num_addrs < MAX_ADDRS) {
195 : struct in_addr ip;
196 0 : inet_aton(p, &ip);
197 0 : ip.s_addr = ntohl(ip.s_addr);
198 0 : addr_list[num_addrs] = &addrs[num_addrs * 4];
199 0 : addrs[num_addrs * 4 + 0] = (ip.s_addr >> 24) & 0xff;
200 0 : addrs[num_addrs * 4 + 1] = (ip.s_addr >> 16) & 0xff;
201 0 : addrs[num_addrs * 4 + 2] = (ip.s_addr >> 8) & 0xff;
202 0 : addrs[num_addrs * 4 + 3] = (ip.s_addr >> 0) & 0xff;
203 0 : addr_list[++num_addrs] = NULL;
204 : }
205 0 : he.h_addr_list = addr_list;
206 0 : return &he;
207 : }
208 : }
209 :
210 : ROKEN_LIB_FUNCTION struct hostent* ROKEN_LIB_CALL
211 : roken_gethostbyname(const char *hostname)
212 0 : {
213 : struct hostent *he;
214 0 : he = gethostbyname(hostname);
215 0 : if(he)
216 0 : return he;
217 0 : return roken_gethostby(hostname);
218 : }
219 :
220 : ROKEN_LIB_FUNCTION struct hostent* ROKEN_LIB_CALL
221 : roken_gethostbyaddr(const void *addr, size_t len, int type)
222 0 : {
223 : struct in_addr a;
224 : const char *p;
225 : struct hostent *he;
226 0 : he = gethostbyaddr(addr, len, type);
227 0 : if(he)
228 0 : return he;
229 0 : if(type != AF_INET || len != 4)
230 0 : return NULL;
231 0 : p = addr;
232 0 : a.s_addr = htonl((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]);
233 0 : return roken_gethostby(inet_ntoa(a));
234 : }
235 :
236 : #if 0
237 :
238 : /* this program can be used as a cgi `script' to lookup names and
239 : ip-addresses */
240 :
241 : #include <stdio.h>
242 : #include <stdlib.h>
243 : #include <netdb.h>
244 : #include <sys/param.h>
245 :
246 : int
247 : main(int argc, char **argv)
248 : {
249 : char *query = getenv("QUERY_STRING");
250 : char host[MAXHOSTNAMELEN];
251 : int i;
252 : struct hostent *he;
253 :
254 : printf("Content-type: text/plain\n\n");
255 : if(query == NULL)
256 : exit(0);
257 : he = gethostbyname(query);
258 : strncpy(host, he->h_name, sizeof(host));
259 : host[sizeof(host) - 1] = '\0';
260 : he = gethostbyaddr(he->h_addr, he->h_length, AF_INET);
261 : printf("%s\n", he->h_name);
262 : for(i = 0; he->h_addr_list[i]; i++) {
263 : struct in_addr ip;
264 : unsigned char *p = (unsigned char*)he->h_addr_list[i];
265 : ip.s_addr = htonl((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]);
266 : printf("%s\n", inet_ntoa(ip));
267 : }
268 : exit(0);
269 : }
270 :
271 : #endif
|
