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-rw-r--r--lib/roken/roken_gethostby.c274
1 files changed, 274 insertions, 0 deletions
diff --git a/lib/roken/roken_gethostby.c b/lib/roken/roken_gethostby.c
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+++ b/lib/roken/roken_gethostby.c
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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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+RCSID("$Id: roken_gethostby.c 21157 2007-06-18 22:03:13Z lha $");
+#endif
+
+#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);
+ if(proxy_host) {
+ if(make_address(proxy_host, &dns_addr.sin_addr) != 0)
+ return -1;
+ dns_addr.sin_port = htons(proxy_port);
+ asprintf(&dns_req, "http://%s:%d%s", dns_host, dns_port, dns_path);
+ } else {
+ if(make_address(dns_host, &dns_addr.sin_addr) != 0)
+ return -1;
+ dns_addr.sin_port = htons(dns_port);
+ asprintf(&dns_req, "%s", dns_path);
+ }
+ dns_addr.sin_family = AF_INET;
+ return 0;
+}
+
+static void
+split_spec(const char *spec, char **host, int *port, char **path, int def_port)
+{
+ char *p;
+ *host = strdup(spec);
+ 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);
+ *p = '\0';
+ }else
+ if(path)
+ *path = NULL;
+}
+
+
+int ROKEN_LIB_FUNCTION
+roken_gethostby_setup(const char *proxy_spec, const char *dns_spec)
+{
+ char *proxy_host = NULL;
+ int proxy_port = 0;
+ char *dns_host, *dns_path;
+ int dns_port;
+
+ int ret = -1;
+
+ split_spec(dns_spec, &dns_host, &dns_port, &dns_path, 80);
+ if(dns_path == NULL)
+ goto out;
+ if(proxy_spec)
+ split_spec(proxy_spec, &proxy_host, &proxy_port, NULL, 80);
+ ret = setup_int(proxy_host, proxy_port, dns_host, dns_port, dns_path);
+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;
+ char buf[1024];
+ int offset = 0;
+ int n;
+ char *p, *foo;
+
+ if(dns_addr.sin_family == 0)
+ return NULL; /* no configured host */
+ addr = dns_addr;
+ asprintf(&request, "GET %s?%s HTTP/1.0\r\n\r\n", dns_req, hostname);
+ 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;
+ }
+ if(write(s, request, strlen(request)) != strlen(request)) {
+ 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;
+ }
+}
+
+struct hostent*
+roken_gethostbyname(const char *hostname)
+{
+ struct hostent *he;
+ he = gethostbyname(hostname);
+ if(he)
+ return he;
+ return roken_gethostby(hostname);
+}
+
+struct hostent* ROKEN_LIB_FUNCTION
+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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