Merge master.kernel.org:/home/rmk/linux-2.6-arm
[linux-2.6] / net / netfilter / nf_conntrack_amanda.c
1 /* Amanda extension for IP connection tracking
2  *
3  * (C) 2002 by Brian J. Murrell <netfilter@interlinx.bc.ca>
4  * based on HW's ip_conntrack_irc.c as well as other modules
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/moduleparam.h>
14 #include <linux/textsearch.h>
15 #include <linux/skbuff.h>
16 #include <linux/in.h>
17 #include <linux/udp.h>
18 #include <linux/netfilter.h>
19
20 #include <net/netfilter/nf_conntrack.h>
21 #include <net/netfilter/nf_conntrack_expect.h>
22 #include <net/netfilter/nf_conntrack_ecache.h>
23 #include <net/netfilter/nf_conntrack_helper.h>
24 #include <linux/netfilter/nf_conntrack_amanda.h>
25
26 static unsigned int master_timeout __read_mostly = 300;
27 static char *ts_algo = "kmp";
28
29 MODULE_AUTHOR("Brian J. Murrell <netfilter@interlinx.bc.ca>");
30 MODULE_DESCRIPTION("Amanda connection tracking module");
31 MODULE_LICENSE("GPL");
32 MODULE_ALIAS("ip_conntrack_amanda");
33
34 module_param(master_timeout, uint, 0600);
35 MODULE_PARM_DESC(master_timeout, "timeout for the master connection");
36 module_param(ts_algo, charp, 0400);
37 MODULE_PARM_DESC(ts_algo, "textsearch algorithm to use (default kmp)");
38
39 unsigned int (*nf_nat_amanda_hook)(struct sk_buff *skb,
40                                    enum ip_conntrack_info ctinfo,
41                                    unsigned int matchoff,
42                                    unsigned int matchlen,
43                                    struct nf_conntrack_expect *exp)
44                                    __read_mostly;
45 EXPORT_SYMBOL_GPL(nf_nat_amanda_hook);
46
47 enum amanda_strings {
48         SEARCH_CONNECT,
49         SEARCH_NEWLINE,
50         SEARCH_DATA,
51         SEARCH_MESG,
52         SEARCH_INDEX,
53 };
54
55 static struct {
56         char                    *string;
57         size_t                  len;
58         struct ts_config        *ts;
59 } search[] __read_mostly = {
60         [SEARCH_CONNECT] = {
61                 .string = "CONNECT ",
62                 .len    = 8,
63         },
64         [SEARCH_NEWLINE] = {
65                 .string = "\n",
66                 .len    = 1,
67         },
68         [SEARCH_DATA] = {
69                 .string = "DATA ",
70                 .len    = 5,
71         },
72         [SEARCH_MESG] = {
73                 .string = "MESG ",
74                 .len    = 5,
75         },
76         [SEARCH_INDEX] = {
77                 .string = "INDEX ",
78                 .len    = 6,
79         },
80 };
81
82 static int amanda_help(struct sk_buff *skb,
83                        unsigned int protoff,
84                        struct nf_conn *ct,
85                        enum ip_conntrack_info ctinfo)
86 {
87         struct ts_state ts;
88         struct nf_conntrack_expect *exp;
89         struct nf_conntrack_tuple *tuple;
90         unsigned int dataoff, start, stop, off, i;
91         char pbuf[sizeof("65535")], *tmp;
92         u_int16_t len;
93         __be16 port;
94         int family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
95         int ret = NF_ACCEPT;
96         typeof(nf_nat_amanda_hook) nf_nat_amanda;
97
98         /* Only look at packets from the Amanda server */
99         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
100                 return NF_ACCEPT;
101
102         /* increase the UDP timeout of the master connection as replies from
103          * Amanda clients to the server can be quite delayed */
104         nf_ct_refresh(ct, skb, master_timeout * HZ);
105
106         /* No data? */
107         dataoff = protoff + sizeof(struct udphdr);
108         if (dataoff >= skb->len) {
109                 if (net_ratelimit())
110                         printk("amanda_help: skblen = %u\n", skb->len);
111                 return NF_ACCEPT;
112         }
113
114         memset(&ts, 0, sizeof(ts));
115         start = skb_find_text(skb, dataoff, skb->len,
116                               search[SEARCH_CONNECT].ts, &ts);
117         if (start == UINT_MAX)
118                 goto out;
119         start += dataoff + search[SEARCH_CONNECT].len;
120
121         memset(&ts, 0, sizeof(ts));
122         stop = skb_find_text(skb, start, skb->len,
123                              search[SEARCH_NEWLINE].ts, &ts);
124         if (stop == UINT_MAX)
125                 goto out;
126         stop += start;
127
128         for (i = SEARCH_DATA; i <= SEARCH_INDEX; i++) {
129                 memset(&ts, 0, sizeof(ts));
130                 off = skb_find_text(skb, start, stop, search[i].ts, &ts);
131                 if (off == UINT_MAX)
132                         continue;
133                 off += start + search[i].len;
134
135                 len = min_t(unsigned int, sizeof(pbuf) - 1, stop - off);
136                 if (skb_copy_bits(skb, off, pbuf, len))
137                         break;
138                 pbuf[len] = '\0';
139
140                 port = htons(simple_strtoul(pbuf, &tmp, 10));
141                 len = tmp - pbuf;
142                 if (port == 0 || len > 5)
143                         break;
144
145                 exp = nf_ct_expect_alloc(ct);
146                 if (exp == NULL) {
147                         ret = NF_DROP;
148                         goto out;
149                 }
150                 tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
151                 nf_ct_expect_init(exp, family, &tuple->src.u3, &tuple->dst.u3,
152                                   IPPROTO_TCP, NULL, &port);
153
154                 nf_nat_amanda = rcu_dereference(nf_nat_amanda_hook);
155                 if (nf_nat_amanda && ct->status & IPS_NAT_MASK)
156                         ret = nf_nat_amanda(skb, ctinfo, off - dataoff,
157                                             len, exp);
158                 else if (nf_ct_expect_related(exp) != 0)
159                         ret = NF_DROP;
160                 nf_ct_expect_put(exp);
161         }
162
163 out:
164         return ret;
165 }
166
167 static struct nf_conntrack_helper amanda_helper[2] __read_mostly = {
168         {
169                 .name                   = "amanda",
170                 .max_expected           = 3,
171                 .timeout                = 180,
172                 .me                     = THIS_MODULE,
173                 .help                   = amanda_help,
174                 .tuple.src.l3num        = AF_INET,
175                 .tuple.src.u.udp.port   = __constant_htons(10080),
176                 .tuple.dst.protonum     = IPPROTO_UDP,
177         },
178         {
179                 .name                   = "amanda",
180                 .max_expected           = 3,
181                 .timeout                = 180,
182                 .me                     = THIS_MODULE,
183                 .help                   = amanda_help,
184                 .tuple.src.l3num        = AF_INET6,
185                 .tuple.src.u.udp.port   = __constant_htons(10080),
186                 .tuple.dst.protonum     = IPPROTO_UDP,
187         },
188 };
189
190 static void __exit nf_conntrack_amanda_fini(void)
191 {
192         int i;
193
194         nf_conntrack_helper_unregister(&amanda_helper[0]);
195         nf_conntrack_helper_unregister(&amanda_helper[1]);
196         for (i = 0; i < ARRAY_SIZE(search); i++)
197                 textsearch_destroy(search[i].ts);
198 }
199
200 static int __init nf_conntrack_amanda_init(void)
201 {
202         int ret, i;
203
204         for (i = 0; i < ARRAY_SIZE(search); i++) {
205                 search[i].ts = textsearch_prepare(ts_algo, search[i].string,
206                                                   search[i].len,
207                                                   GFP_KERNEL, TS_AUTOLOAD);
208                 if (IS_ERR(search[i].ts)) {
209                         ret = PTR_ERR(search[i].ts);
210                         goto err1;
211                 }
212         }
213         ret = nf_conntrack_helper_register(&amanda_helper[0]);
214         if (ret < 0)
215                 goto err1;
216         ret = nf_conntrack_helper_register(&amanda_helper[1]);
217         if (ret < 0)
218                 goto err2;
219         return 0;
220
221 err2:
222         nf_conntrack_helper_unregister(&amanda_helper[0]);
223 err1:
224         while (--i >= 0)
225                 textsearch_destroy(search[i].ts);
226
227         return ret;
228 }
229
230 module_init(nf_conntrack_amanda_init);
231 module_exit(nf_conntrack_amanda_fini);