1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
3 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 */
9
10 #include <linux/types.h>
11 #include <linux/timer.h>
12 #include <linux/module.h>
13 #include <linux/udp.h>
14 #include <linux/seq_file.h>
15 #include <linux/skbuff.h>
16 #include <linux/ipv6.h>
17 #include <net/ip6_checksum.h>
18 #include <net/checksum.h>
19
20 #include <linux/netfilter.h>
21 #include <linux/netfilter_ipv4.h>
22 #include <linux/netfilter_ipv6.h>
23 #include <net/netfilter/nf_conntrack_l4proto.h>
24 #include <net/netfilter/nf_conntrack_ecache.h>
25 #include <net/netfilter/nf_log.h>
26 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
27 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
28
29 static unsigned int udp_timeouts[UDP_CT_MAX] = {
30 [UDP_CT_UNREPLIED] = 30*HZ,
31 [UDP_CT_REPLIED] = 180*HZ,
32 };
33
34 static inline struct nf_udp_net *udp_pernet(struct net *net)
35 {
36 return &net->ct.nf_ct_proto.udp;
37 }
38
39 static bool udp_pkt_to_tuple(const struct sk_buff *skb,
40 unsigned int dataoff,
41 struct nf_conntrack_tuple *tuple)
42 {
43 const struct udphdr *hp;
44 struct udphdr _hdr;
45
46 /* Actually only need first 8 bytes. */
47 hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
48 if (hp == NULL)
49 return false;
50
51 tuple->src.u.udp.port = hp->source;
52 tuple->dst.u.udp.port = hp->dest;
53
54 return true;
55 }
56
57 static bool udp_invert_tuple(struct nf_conntrack_tuple *tuple,
58 const struct nf_conntrack_tuple *orig)
59 {
60 tuple->src.u.udp.port = orig->dst.u.udp.port;
61 tuple->dst.u.udp.port = orig->src.u.udp.port;
62 return true;
63 }
64
65 /* Print out the per-protocol part of the tuple. */
66 static void udp_print_tuple(struct seq_file *s,
67 const struct nf_conntrack_tuple *tuple)
68 {
69 seq_printf(s, "sport=%hu dport=%hu ",
70 ntohs(tuple->src.u.udp.port),
71 ntohs(tuple->dst.u.udp.port));
72 }
73
74 static unsigned int *udp_get_timeouts(struct net *net)
75 {
76 return udp_pernet(net)->timeouts;
77 }
78
79 /* Returns verdict for packet, and may modify conntracktype */
80 static int udp_packet(struct nf_conn *ct,
81 const struct sk_buff *skb,
82 unsigned int dataoff,
83 enum ip_conntrack_info ctinfo,
84 u_int8_t pf,
85 unsigned int hooknum,
86 unsigned int *timeouts)
87 {
88 /* If we've seen traffic both ways, this is some kind of UDP
89 stream. Extend timeout. */
90 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
91 nf_ct_refresh_acct(ct, ctinfo, skb,
92 timeouts[UDP_CT_REPLIED]);
93 /* Also, more likely to be important, and not a probe */
94 if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
95 nf_conntrack_event_cache(IPCT_ASSURED, ct);
96 } else {
97 nf_ct_refresh_acct(ct, ctinfo, skb,
98 timeouts[UDP_CT_UNREPLIED]);
99 }
100 return NF_ACCEPT;
101 }
102
103 /* Called when a new connection for this protocol found. */
104 static bool udp_new(struct nf_conn *ct, const struct sk_buff *skb,
105 unsigned int dataoff, unsigned int *timeouts)
106 {
107 return true;
108 }
109
110 static int udp_error(struct net *net, struct nf_conn *tmpl, struct sk_buff *skb,
111 unsigned int dataoff, enum ip_conntrack_info *ctinfo,
112 u_int8_t pf,
113 unsigned int hooknum)
114 {
115 unsigned int udplen = skb->len - dataoff;
116 const struct udphdr *hdr;
117 struct udphdr _hdr;
118
119 /* Header is too small? */
120 hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
121 if (hdr == NULL) {
122 if (LOG_INVALID(net, IPPROTO_UDP))
123 nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
124 "nf_ct_udp: short packet ");
125 return -NF_ACCEPT;
126 }
127
128 /* Truncated/malformed packets */
129 if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) {
130 if (LOG_INVALID(net, IPPROTO_UDP))
131 nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
132 "nf_ct_udp: truncated/malformed packet ");
133 return -NF_ACCEPT;
134 }
135
136 /* Packet with no checksum */
137 if (!hdr->check)
138 return NF_ACCEPT;
139
140 /* Checksum invalid? Ignore.
141 * We skip checking packets on the outgoing path
142 * because the checksum is assumed to be correct.
143 * FIXME: Source route IP option packets --RR */
144 if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
145 nf_checksum(skb, hooknum, dataoff, IPPROTO_UDP, pf)) {
146 if (LOG_INVALID(net, IPPROTO_UDP))
147 nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
148 "nf_ct_udp: bad UDP checksum ");
149 return -NF_ACCEPT;
150 }
151
152 return NF_ACCEPT;
153 }
154
155 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
156
157 #include <linux/netfilter/nfnetlink.h>
158 #include <linux/netfilter/nfnetlink_cttimeout.h>
159
160 static int udp_timeout_nlattr_to_obj(struct nlattr *tb[],
161 struct net *net, void *data)
162 {
163 unsigned int *timeouts = data;
164 struct nf_udp_net *un = udp_pernet(net);
165
166 /* set default timeouts for UDP. */
167 timeouts[UDP_CT_UNREPLIED] = un->timeouts[UDP_CT_UNREPLIED];
168 timeouts[UDP_CT_REPLIED] = un->timeouts[UDP_CT_REPLIED];
169
170 if (tb[CTA_TIMEOUT_UDP_UNREPLIED]) {
171 timeouts[UDP_CT_UNREPLIED] =
172 ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDP_UNREPLIED])) * HZ;
173 }
174 if (tb[CTA_TIMEOUT_UDP_REPLIED]) {
175 timeouts[UDP_CT_REPLIED] =
176 ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDP_REPLIED])) * HZ;
177 }
178 return 0;
179 }
180
181 static int
182 udp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
183 {
184 const unsigned int *timeouts = data;
185
186 if (nla_put_be32(skb, CTA_TIMEOUT_UDP_UNREPLIED,
187 htonl(timeouts[UDP_CT_UNREPLIED] / HZ)) ||
188 nla_put_be32(skb, CTA_TIMEOUT_UDP_REPLIED,
189 htonl(timeouts[UDP_CT_REPLIED] / HZ)))
190 goto nla_put_failure;
191 return 0;
192
193 nla_put_failure:
194 return -ENOSPC;
195 }
196
197 static const struct nla_policy
198 udp_timeout_nla_policy[CTA_TIMEOUT_UDP_MAX+1] = {
199 [CTA_TIMEOUT_UDP_UNREPLIED] = { .type = NLA_U32 },
200 [CTA_TIMEOUT_UDP_REPLIED] = { .type = NLA_U32 },
201 };
202 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
203
204 #ifdef CONFIG_SYSCTL
205 static struct ctl_table udp_sysctl_table[] = {
206 {
207 .procname = "nf_conntrack_udp_timeout",
208 .maxlen = sizeof(unsigned int),
209 .mode = 0644,
210 .proc_handler = proc_dointvec_jiffies,
211 },
212 {
213 .procname = "nf_conntrack_udp_timeout_stream",
214 .maxlen = sizeof(unsigned int),
215 .mode = 0644,
216 .proc_handler = proc_dointvec_jiffies,
217 },
218 { }
219 };
220 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
221 static struct ctl_table udp_compat_sysctl_table[] = {
222 {
223 .procname = "ip_conntrack_udp_timeout",
224 .maxlen = sizeof(unsigned int),
225 .mode = 0644,
226 .proc_handler = proc_dointvec_jiffies,
227 },
228 {
229 .procname = "ip_conntrack_udp_timeout_stream",
230 .maxlen = sizeof(unsigned int),
231 .mode = 0644,
232 .proc_handler = proc_dointvec_jiffies,
233 },
234 { }
235 };
236 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
237 #endif /* CONFIG_SYSCTL */
238
239 static int udp_kmemdup_sysctl_table(struct nf_proto_net *pn,
240 struct nf_udp_net *un)
241 {
242 #ifdef CONFIG_SYSCTL
243 if (pn->ctl_table)
244 return 0;
245 pn->ctl_table = kmemdup(udp_sysctl_table,
246 sizeof(udp_sysctl_table),
247 GFP_KERNEL);
248 if (!pn->ctl_table)
249 return -ENOMEM;
250 pn->ctl_table[0].data = &un->timeouts[UDP_CT_UNREPLIED];
251 pn->ctl_table[1].data = &un->timeouts[UDP_CT_REPLIED];
252 #endif
253 return 0;
254 }
255
256 static int udp_kmemdup_compat_sysctl_table(struct nf_proto_net *pn,
257 struct nf_udp_net *un)
258 {
259 #ifdef CONFIG_SYSCTL
260 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
261 pn->ctl_compat_table = kmemdup(udp_compat_sysctl_table,
262 sizeof(udp_compat_sysctl_table),
263 GFP_KERNEL);
264 if (!pn->ctl_compat_table)
265 return -ENOMEM;
266
267 pn->ctl_compat_table[0].data = &un->timeouts[UDP_CT_UNREPLIED];
268 pn->ctl_compat_table[1].data = &un->timeouts[UDP_CT_REPLIED];
269 #endif
270 #endif
271 return 0;
272 }
273
274 static int udp_init_net(struct net *net, u_int16_t proto)
275 {
276 int ret;
277 struct nf_udp_net *un = udp_pernet(net);
278 struct nf_proto_net *pn = &un->pn;
279
280 if (!pn->users) {
281 int i;
282
283 for (i = 0; i < UDP_CT_MAX; i++)
284 un->timeouts[i] = udp_timeouts[i];
285 }
286
287 if (proto == AF_INET) {
288 ret = udp_kmemdup_compat_sysctl_table(pn, un);
289 if (ret < 0)
290 return ret;
291
292 ret = udp_kmemdup_sysctl_table(pn, un);
293 if (ret < 0)
294 nf_ct_kfree_compat_sysctl_table(pn);
295 } else
296 ret = udp_kmemdup_sysctl_table(pn, un);
297
298 return ret;
299 }
300
301 static struct nf_proto_net *udp_get_net_proto(struct net *net)
302 {
303 return &net->ct.nf_ct_proto.udp.pn;
304 }
305
306 struct nf_conntrack_l4proto nf_conntrack_l4proto_udp4 __read_mostly =
307 {
308 .l3proto = PF_INET,
309 .l4proto = IPPROTO_UDP,
310 .name = "udp",
311 .pkt_to_tuple = udp_pkt_to_tuple,
312 .invert_tuple = udp_invert_tuple,
313 .print_tuple = udp_print_tuple,
314 .packet = udp_packet,
315 .get_timeouts = udp_get_timeouts,
316 .new = udp_new,
317 .error = udp_error,
318 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
319 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
320 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
321 .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
322 .nla_policy = nf_ct_port_nla_policy,
323 #endif
324 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
325 .ctnl_timeout = {
326 .nlattr_to_obj = udp_timeout_nlattr_to_obj,
327 .obj_to_nlattr = udp_timeout_obj_to_nlattr,
328 .nlattr_max = CTA_TIMEOUT_UDP_MAX,
329 .obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX,
330 .nla_policy = udp_timeout_nla_policy,
331 },
332 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
333 .init_net = udp_init_net,
334 .get_net_proto = udp_get_net_proto,
335 };
336 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp4);
337
338 struct nf_conntrack_l4proto nf_conntrack_l4proto_udp6 __read_mostly =
339 {
340 .l3proto = PF_INET6,
341 .l4proto = IPPROTO_UDP,
342 .name = "udp",
343 .pkt_to_tuple = udp_pkt_to_tuple,
344 .invert_tuple = udp_invert_tuple,
345 .print_tuple = udp_print_tuple,
346 .packet = udp_packet,
347 .get_timeouts = udp_get_timeouts,
348 .new = udp_new,
349 .error = udp_error,
350 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
351 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
352 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
353 .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
354 .nla_policy = nf_ct_port_nla_policy,
355 #endif
356 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
357 .ctnl_timeout = {
358 .nlattr_to_obj = udp_timeout_nlattr_to_obj,
359 .obj_to_nlattr = udp_timeout_obj_to_nlattr,
360 .nlattr_max = CTA_TIMEOUT_UDP_MAX,
361 .obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX,
362 .nla_policy = udp_timeout_nla_policy,
363 },
364 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
365 .init_net = udp_init_net,
366 .get_net_proto = udp_get_net_proto,
367 };
368 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp6);
369
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