aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--fs/cifs/dns_resolve.c123
-rw-r--r--fs/cifs/dns_resolve.h32
2 files changed, 155 insertions, 0 deletions
diff --git a/fs/cifs/dns_resolve.c b/fs/cifs/dns_resolve.c
new file mode 100644
index 000000000000..777a086abd6f
--- /dev/null
+++ b/fs/cifs/dns_resolve.c
@@ -0,0 +1,123 @@
1/*
2 * fs/cifs/dns_resolve.c
3 *
4 * Copyright (c) 2007 Igor Mammedov
5 * Author(s): Igor Mammedov (niallain@gmail.com)
6 * Steve French (sfrench@us.ibm.com)
7 *
8 * Contains the CIFS DFS upcall routines used for hostname to
9 * IP address translation.
10 *
11 * This library is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU Lesser General Public License as published
13 * by the Free Software Foundation; either version 2.1 of the License, or
14 * (at your option) any later version.
15 *
16 * This library is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
19 * the GNU Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public License
22 * along with this library; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 */
25
26#include <keys/user-type.h>
27#include "dns_resolve.h"
28#include "cifsglob.h"
29#include "cifsproto.h"
30#include "cifs_debug.h"
31
32static int dns_resolver_instantiate(struct key *key, const void *data,
33 size_t datalen)
34{
35 int rc = 0;
36 char *ip;
37
38 ip = kmalloc(datalen+1, GFP_KERNEL);
39 if (!ip)
40 return -ENOMEM;
41
42 memcpy(ip, data, datalen);
43 ip[datalen] = '\0';
44
45 rcu_assign_pointer(key->payload.data, ip);
46
47 return rc;
48}
49
50struct key_type key_type_dns_resolver = {
51 .name = "dns_resolver",
52 .def_datalen = sizeof(struct in_addr),
53 .describe = user_describe,
54 .instantiate = dns_resolver_instantiate,
55 .match = user_match,
56};
57
58
59/* Resolves server name to ip address.
60 * input:
61 * unc - server UNC
62 * output:
63 * *ip_addr - pointer to server ip, caller responcible for freeing it.
64 * return 0 on success
65 */
66int
67dns_resolve_server_name_to_ip(const char *unc, char **ip_addr) {
68 int rc = -EAGAIN;
69 struct key *rkey;
70 char *name;
71 int len;
72
73 if ((!ip_addr) || (!unc))
74 return -EINVAL;
75
76 /* search for server name delimiter */
77 len = strlen(unc);
78 if (len < 3) {
79 cFYI(1, ("%s: unc is too short: %s", __FUNCTION__, unc));
80 return -EINVAL;
81 }
82 len -= 2;
83 name = memchr(unc+2, '\\', len);
84 if (!name) {
85 cFYI(1, ("%s: probably server name is whole unc: %s",
86 __FUNCTION__, unc));
87 } else {
88 len = (name - unc) - 2/* leading // */;
89 }
90
91 name = kmalloc(len+1, GFP_KERNEL);
92 if (!name) {
93 rc = -ENOMEM;
94 return rc;
95 }
96 memcpy(name, unc+2, len);
97 name[len] = 0;
98
99 rkey = request_key(&key_type_dns_resolver, name, "");
100 if (!IS_ERR(rkey)) {
101 len = strlen(rkey->payload.data);
102 *ip_addr = kmalloc(len+1, GFP_KERNEL);
103 if (*ip_addr) {
104 memcpy(*ip_addr, rkey->payload.data, len);
105 (*ip_addr)[len] = '\0';
106 cFYI(1, ("%s: resolved: %s to %s", __FUNCTION__,
107 rkey->description,
108 *ip_addr
109 ));
110 rc = 0;
111 } else {
112 rc = -ENOMEM;
113 }
114 key_put(rkey);
115 } else {
116 cERROR(1, ("%s: unable to resolve: %s", __FUNCTION__, name));
117 }
118
119 kfree(name);
120 return rc;
121}
122
123
diff --git a/fs/cifs/dns_resolve.h b/fs/cifs/dns_resolve.h
new file mode 100644
index 000000000000..073fdc3db419
--- /dev/null
+++ b/fs/cifs/dns_resolve.h
@@ -0,0 +1,32 @@
1/*
2 * fs/cifs/dns_resolve.h -- DNS Resolver upcall management for CIFS DFS
3 * Handles host name to IP address resolution
4 *
5 * Copyright (c) International Business Machines Corp., 2008
6 * Author(s): Steve French (sfrench@us.ibm.com)
7 *
8 * This library is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU Lesser General Public License as published
10 * by the Free Software Foundation; either version 2.1 of the License, or
11 * (at your option) any later version.
12 *
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
16 * the GNU Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public License
19 * along with this library; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 */
22
23#ifndef _DNS_RESOLVE_H
24#define _DNS_RESOLVE_H
25
26#ifdef __KERNEL__
27#include <linux/key-type.h>
28extern struct key_type key_type_dns_resolver;
29extern int dns_resolve_server_name_to_ip(const char *unc, char **ip_addr);
30#endif /* KERNEL */
31
32#endif /* _DNS_RESOLVE_H */