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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 | |
f229f6ce | 5 | * (C) 2006 Patrick McHardy <kaber@trash.net> |
16958900 PM |
6 | * |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License | |
9 | * as published by the Free Software Foundation; either version | |
10 | * 2 of the License, or (at your option) any later version. | |
11 | */ | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/moduleparam.h> | |
15 | #include <linux/textsearch.h> | |
16 | #include <linux/skbuff.h> | |
17 | #include <linux/in.h> | |
18 | #include <linux/udp.h> | |
1863f096 | 19 | #include <linux/netfilter.h> |
5a0e3ad6 | 20 | #include <linux/gfp.h> |
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21 | |
22 | #include <net/netfilter/nf_conntrack.h> | |
23 | #include <net/netfilter/nf_conntrack_expect.h> | |
24 | #include <net/netfilter/nf_conntrack_ecache.h> | |
25 | #include <net/netfilter/nf_conntrack_helper.h> | |
26 | #include <linux/netfilter/nf_conntrack_amanda.h> | |
27 | ||
28 | static unsigned int master_timeout __read_mostly = 300; | |
29 | static char *ts_algo = "kmp"; | |
30 | ||
31 | MODULE_AUTHOR("Brian J. Murrell <netfilter@interlinx.bc.ca>"); | |
32 | MODULE_DESCRIPTION("Amanda connection tracking module"); | |
33 | MODULE_LICENSE("GPL"); | |
34 | MODULE_ALIAS("ip_conntrack_amanda"); | |
4dc06f96 | 35 | MODULE_ALIAS_NFCT_HELPER("amanda"); |
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36 | |
37 | module_param(master_timeout, uint, 0600); | |
38 | MODULE_PARM_DESC(master_timeout, "timeout for the master connection"); | |
39 | module_param(ts_algo, charp, 0400); | |
40 | MODULE_PARM_DESC(ts_algo, "textsearch algorithm to use (default kmp)"); | |
41 | ||
3db05fea | 42 | unsigned int (*nf_nat_amanda_hook)(struct sk_buff *skb, |
16958900 | 43 | enum ip_conntrack_info ctinfo, |
051966c0 | 44 | unsigned int protoff, |
16958900 PM |
45 | unsigned int matchoff, |
46 | unsigned int matchlen, | |
47 | struct nf_conntrack_expect *exp) | |
48 | __read_mostly; | |
49 | EXPORT_SYMBOL_GPL(nf_nat_amanda_hook); | |
50 | ||
51 | enum amanda_strings { | |
52 | SEARCH_CONNECT, | |
53 | SEARCH_NEWLINE, | |
54 | SEARCH_DATA, | |
55 | SEARCH_MESG, | |
56 | SEARCH_INDEX, | |
57 | }; | |
58 | ||
59 | static struct { | |
58c0fb0d | 60 | const char *string; |
16958900 PM |
61 | size_t len; |
62 | struct ts_config *ts; | |
63 | } search[] __read_mostly = { | |
64 | [SEARCH_CONNECT] = { | |
65 | .string = "CONNECT ", | |
66 | .len = 8, | |
67 | }, | |
68 | [SEARCH_NEWLINE] = { | |
69 | .string = "\n", | |
70 | .len = 1, | |
71 | }, | |
72 | [SEARCH_DATA] = { | |
73 | .string = "DATA ", | |
74 | .len = 5, | |
75 | }, | |
76 | [SEARCH_MESG] = { | |
77 | .string = "MESG ", | |
78 | .len = 5, | |
79 | }, | |
80 | [SEARCH_INDEX] = { | |
81 | .string = "INDEX ", | |
82 | .len = 6, | |
83 | }, | |
84 | }; | |
85 | ||
3db05fea | 86 | static int amanda_help(struct sk_buff *skb, |
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87 | unsigned int protoff, |
88 | struct nf_conn *ct, | |
89 | enum ip_conntrack_info ctinfo) | |
90 | { | |
91 | struct ts_state ts; | |
92 | struct nf_conntrack_expect *exp; | |
93 | struct nf_conntrack_tuple *tuple; | |
94 | unsigned int dataoff, start, stop, off, i; | |
95 | char pbuf[sizeof("65535")], *tmp; | |
96 | u_int16_t len; | |
97 | __be16 port; | |
16958900 PM |
98 | int ret = NF_ACCEPT; |
99 | typeof(nf_nat_amanda_hook) nf_nat_amanda; | |
100 | ||
101 | /* Only look at packets from the Amanda server */ | |
102 | if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) | |
103 | return NF_ACCEPT; | |
104 | ||
105 | /* increase the UDP timeout of the master connection as replies from | |
106 | * Amanda clients to the server can be quite delayed */ | |
3db05fea | 107 | nf_ct_refresh(ct, skb, master_timeout * HZ); |
16958900 PM |
108 | |
109 | /* No data? */ | |
110 | dataoff = protoff + sizeof(struct udphdr); | |
3db05fea | 111 | if (dataoff >= skb->len) { |
e87cc472 | 112 | net_err_ratelimited("amanda_help: skblen = %u\n", skb->len); |
16958900 PM |
113 | return NF_ACCEPT; |
114 | } | |
115 | ||
116 | memset(&ts, 0, sizeof(ts)); | |
3db05fea | 117 | start = skb_find_text(skb, dataoff, skb->len, |
16958900 PM |
118 | search[SEARCH_CONNECT].ts, &ts); |
119 | if (start == UINT_MAX) | |
120 | goto out; | |
121 | start += dataoff + search[SEARCH_CONNECT].len; | |
122 | ||
123 | memset(&ts, 0, sizeof(ts)); | |
3db05fea | 124 | stop = skb_find_text(skb, start, skb->len, |
16958900 PM |
125 | search[SEARCH_NEWLINE].ts, &ts); |
126 | if (stop == UINT_MAX) | |
127 | goto out; | |
128 | stop += start; | |
129 | ||
130 | for (i = SEARCH_DATA; i <= SEARCH_INDEX; i++) { | |
131 | memset(&ts, 0, sizeof(ts)); | |
3db05fea | 132 | off = skb_find_text(skb, start, stop, search[i].ts, &ts); |
16958900 PM |
133 | if (off == UINT_MAX) |
134 | continue; | |
135 | off += start + search[i].len; | |
136 | ||
137 | len = min_t(unsigned int, sizeof(pbuf) - 1, stop - off); | |
3db05fea | 138 | if (skb_copy_bits(skb, off, pbuf, len)) |
16958900 PM |
139 | break; |
140 | pbuf[len] = '\0'; | |
141 | ||
142 | port = htons(simple_strtoul(pbuf, &tmp, 10)); | |
143 | len = tmp - pbuf; | |
144 | if (port == 0 || len > 5) | |
145 | break; | |
146 | ||
6823645d | 147 | exp = nf_ct_expect_alloc(ct); |
16958900 | 148 | if (exp == NULL) { |
b20ab9cc | 149 | nf_ct_helper_log(skb, ct, "cannot alloc expectation"); |
16958900 PM |
150 | ret = NF_DROP; |
151 | goto out; | |
152 | } | |
153 | tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; | |
5e8fbe2a PM |
154 | nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, |
155 | nf_ct_l3num(ct), | |
6002f266 | 156 | &tuple->src.u3, &tuple->dst.u3, |
6823645d | 157 | IPPROTO_TCP, NULL, &port); |
16958900 PM |
158 | |
159 | nf_nat_amanda = rcu_dereference(nf_nat_amanda_hook); | |
ee6eb966 | 160 | if (nf_nat_amanda && ct->status & IPS_NAT_MASK) |
051966c0 PM |
161 | ret = nf_nat_amanda(skb, ctinfo, protoff, |
162 | off - dataoff, len, exp); | |
b20ab9cc PNA |
163 | else if (nf_ct_expect_related(exp) != 0) { |
164 | nf_ct_helper_log(skb, ct, "cannot add expectation"); | |
16958900 | 165 | ret = NF_DROP; |
b20ab9cc | 166 | } |
6823645d | 167 | nf_ct_expect_put(exp); |
16958900 PM |
168 | } |
169 | ||
170 | out: | |
171 | return ret; | |
172 | } | |
173 | ||
6002f266 PM |
174 | static const struct nf_conntrack_expect_policy amanda_exp_policy = { |
175 | .max_expected = 3, | |
176 | .timeout = 180, | |
177 | }; | |
178 | ||
16958900 PM |
179 | static struct nf_conntrack_helper amanda_helper[2] __read_mostly = { |
180 | { | |
181 | .name = "amanda", | |
16958900 PM |
182 | .me = THIS_MODULE, |
183 | .help = amanda_help, | |
184 | .tuple.src.l3num = AF_INET, | |
09640e63 | 185 | .tuple.src.u.udp.port = cpu_to_be16(10080), |
16958900 | 186 | .tuple.dst.protonum = IPPROTO_UDP, |
6002f266 | 187 | .expect_policy = &amanda_exp_policy, |
16958900 PM |
188 | }, |
189 | { | |
190 | .name = "amanda", | |
16958900 PM |
191 | .me = THIS_MODULE, |
192 | .help = amanda_help, | |
193 | .tuple.src.l3num = AF_INET6, | |
09640e63 | 194 | .tuple.src.u.udp.port = cpu_to_be16(10080), |
16958900 | 195 | .tuple.dst.protonum = IPPROTO_UDP, |
6002f266 | 196 | .expect_policy = &amanda_exp_policy, |
16958900 PM |
197 | }, |
198 | }; | |
199 | ||
200 | static void __exit nf_conntrack_amanda_fini(void) | |
201 | { | |
202 | int i; | |
203 | ||
204 | nf_conntrack_helper_unregister(&amanda_helper[0]); | |
205 | nf_conntrack_helper_unregister(&amanda_helper[1]); | |
206 | for (i = 0; i < ARRAY_SIZE(search); i++) | |
207 | textsearch_destroy(search[i].ts); | |
208 | } | |
209 | ||
210 | static int __init nf_conntrack_amanda_init(void) | |
211 | { | |
212 | int ret, i; | |
213 | ||
16958900 PM |
214 | for (i = 0; i < ARRAY_SIZE(search); i++) { |
215 | search[i].ts = textsearch_prepare(ts_algo, search[i].string, | |
216 | search[i].len, | |
217 | GFP_KERNEL, TS_AUTOLOAD); | |
c764c9ad AM |
218 | if (IS_ERR(search[i].ts)) { |
219 | ret = PTR_ERR(search[i].ts); | |
16958900 | 220 | goto err1; |
c764c9ad | 221 | } |
16958900 PM |
222 | } |
223 | ret = nf_conntrack_helper_register(&amanda_helper[0]); | |
224 | if (ret < 0) | |
225 | goto err1; | |
226 | ret = nf_conntrack_helper_register(&amanda_helper[1]); | |
227 | if (ret < 0) | |
228 | goto err2; | |
229 | return 0; | |
230 | ||
231 | err2: | |
232 | nf_conntrack_helper_unregister(&amanda_helper[0]); | |
233 | err1: | |
c764c9ad AM |
234 | while (--i >= 0) |
235 | textsearch_destroy(search[i].ts); | |
236 | ||
16958900 PM |
237 | return ret; |
238 | } | |
239 | ||
240 | module_init(nf_conntrack_amanda_init); | |
241 | module_exit(nf_conntrack_amanda_fini); |