Commit | Line | Data |
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197c183f SF |
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 | ||
5a0e3ad6 | 26 | #include <linux/slab.h> |
197c183f SF |
27 | #include <keys/user-type.h> |
28 | #include "dns_resolve.h" | |
29 | #include "cifsglob.h" | |
30 | #include "cifsproto.h" | |
31 | #include "cifs_debug.h" | |
32 | ||
9d815234 SF |
33 | /* Checks if supplied name is IP address |
34 | * returns: | |
35 | * 1 - name is IP | |
36 | * 0 - name is not IP | |
37 | */ | |
38 | static int | |
681bf72e | 39 | is_ip(char *name) |
9d815234 | 40 | { |
1e68b2b2 | 41 | struct sockaddr_storage ss; |
9d815234 | 42 | |
1e68b2b2 | 43 | return cifs_convert_address(name, &ss); |
9d815234 SF |
44 | } |
45 | ||
46 | static int | |
47 | dns_resolver_instantiate(struct key *key, const void *data, | |
197c183f SF |
48 | size_t datalen) |
49 | { | |
50 | int rc = 0; | |
51 | char *ip; | |
52 | ||
9d815234 | 53 | ip = kmalloc(datalen + 1, GFP_KERNEL); |
197c183f SF |
54 | if (!ip) |
55 | return -ENOMEM; | |
56 | ||
57 | memcpy(ip, data, datalen); | |
58 | ip[datalen] = '\0'; | |
59 | ||
9d815234 | 60 | /* make sure this looks like an address */ |
681bf72e | 61 | if (!is_ip(ip)) { |
9d815234 SF |
62 | kfree(ip); |
63 | return -EINVAL; | |
64 | } | |
65 | ||
66 | key->type_data.x[0] = datalen; | |
d9fb5c09 | 67 | key->payload.data = ip; |
197c183f SF |
68 | |
69 | return rc; | |
70 | } | |
71 | ||
87ed1d65 JL |
72 | static void |
73 | dns_resolver_destroy(struct key *key) | |
74 | { | |
75 | kfree(key->payload.data); | |
76 | } | |
77 | ||
197c183f SF |
78 | struct key_type key_type_dns_resolver = { |
79 | .name = "dns_resolver", | |
80 | .def_datalen = sizeof(struct in_addr), | |
81 | .describe = user_describe, | |
82 | .instantiate = dns_resolver_instantiate, | |
87ed1d65 | 83 | .destroy = dns_resolver_destroy, |
197c183f SF |
84 | .match = user_match, |
85 | }; | |
86 | ||
197c183f SF |
87 | /* Resolves server name to ip address. |
88 | * input: | |
89 | * unc - server UNC | |
90 | * output: | |
91 | * *ip_addr - pointer to server ip, caller responcible for freeing it. | |
92 | * return 0 on success | |
93 | */ | |
94 | int | |
366781c1 SF |
95 | dns_resolve_server_name_to_ip(const char *unc, char **ip_addr) |
96 | { | |
197c183f | 97 | int rc = -EAGAIN; |
d09e860c | 98 | struct key *rkey = ERR_PTR(-EAGAIN); |
197c183f | 99 | char *name; |
d09e860c | 100 | char *data = NULL; |
197c183f SF |
101 | int len; |
102 | ||
366781c1 | 103 | if (!ip_addr || !unc) |
197c183f SF |
104 | return -EINVAL; |
105 | ||
106 | /* search for server name delimiter */ | |
107 | len = strlen(unc); | |
108 | if (len < 3) { | |
b6b38f70 | 109 | cFYI(1, "%s: unc is too short: %s", __func__, unc); |
197c183f SF |
110 | return -EINVAL; |
111 | } | |
112 | len -= 2; | |
113 | name = memchr(unc+2, '\\', len); | |
114 | if (!name) { | |
b6b38f70 JP |
115 | cFYI(1, "%s: probably server name is whole unc: %s", |
116 | __func__, unc); | |
197c183f SF |
117 | } else { |
118 | len = (name - unc) - 2/* leading // */; | |
119 | } | |
120 | ||
121 | name = kmalloc(len+1, GFP_KERNEL); | |
122 | if (!name) { | |
123 | rc = -ENOMEM; | |
124 | return rc; | |
125 | } | |
126 | memcpy(name, unc+2, len); | |
127 | name[len] = 0; | |
128 | ||
d09e860c | 129 | if (is_ip(name)) { |
b6b38f70 JP |
130 | cFYI(1, "%s: it is IP, skipping dns upcall: %s", |
131 | __func__, name); | |
d09e860c SF |
132 | data = name; |
133 | goto skip_upcall; | |
134 | } | |
135 | ||
197c183f SF |
136 | rkey = request_key(&key_type_dns_resolver, name, ""); |
137 | if (!IS_ERR(rkey)) { | |
9d815234 | 138 | len = rkey->type_data.x[0]; |
d09e860c | 139 | data = rkey->payload.data; |
d09e860c | 140 | } else { |
b6b38f70 | 141 | cERROR(1, "%s: unable to resolve: %s", __func__, name); |
d09e860c SF |
142 | goto out; |
143 | } | |
144 | ||
145 | skip_upcall: | |
146 | if (data) { | |
9d815234 | 147 | *ip_addr = kmalloc(len + 1, GFP_KERNEL); |
d09e860c | 148 | if (*ip_addr) { |
9d815234 | 149 | memcpy(*ip_addr, data, len + 1); |
5651ced3 | 150 | if (!IS_ERR(rkey)) |
b6b38f70 | 151 | cFYI(1, "%s: resolved: %s to %s", __func__, |
5651ced3 IM |
152 | name, |
153 | *ip_addr | |
b6b38f70 | 154 | ); |
197c183f SF |
155 | rc = 0; |
156 | } else { | |
157 | rc = -ENOMEM; | |
158 | } | |
d09e860c SF |
159 | if (!IS_ERR(rkey)) |
160 | key_put(rkey); | |
197c183f SF |
161 | } |
162 | ||
d09e860c | 163 | out: |
197c183f SF |
164 | kfree(name); |
165 | return rc; | |
166 | } | |
167 | ||
168 |