[NETFILTER]: ctnetlink: use netlink policy
[linux-2.6.git] / net / netfilter / nf_conntrack_proto_udp.c
1 /* (C) 1999-2001 Paul `Rusty' Russell
2  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  */
8
9 #include <linux/types.h>
10 #include <linux/timer.h>
11 #include <linux/module.h>
12 #include <linux/udp.h>
13 #include <linux/seq_file.h>
14 #include <linux/skbuff.h>
15 #include <linux/ipv6.h>
16 #include <net/ip6_checksum.h>
17 #include <net/checksum.h>
18
19 #include <linux/netfilter.h>
20 #include <linux/netfilter_ipv4.h>
21 #include <linux/netfilter_ipv6.h>
22 #include <net/netfilter/nf_conntrack_l4proto.h>
23 #include <net/netfilter/nf_conntrack_ecache.h>
24
25 static unsigned int nf_ct_udp_timeout __read_mostly = 30*HZ;
26 static unsigned int nf_ct_udp_timeout_stream __read_mostly = 180*HZ;
27
28 static int udp_pkt_to_tuple(const struct sk_buff *skb,
29                              unsigned int dataoff,
30                              struct nf_conntrack_tuple *tuple)
31 {
32         struct udphdr _hdr, *hp;
33
34         /* Actually only need first 8 bytes. */
35         hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
36         if (hp == NULL)
37                 return 0;
38
39         tuple->src.u.udp.port = hp->source;
40         tuple->dst.u.udp.port = hp->dest;
41
42         return 1;
43 }
44
45 static int udp_invert_tuple(struct nf_conntrack_tuple *tuple,
46                             const struct nf_conntrack_tuple *orig)
47 {
48         tuple->src.u.udp.port = orig->dst.u.udp.port;
49         tuple->dst.u.udp.port = orig->src.u.udp.port;
50         return 1;
51 }
52
53 /* Print out the per-protocol part of the tuple. */
54 static int udp_print_tuple(struct seq_file *s,
55                            const struct nf_conntrack_tuple *tuple)
56 {
57         return seq_printf(s, "sport=%hu dport=%hu ",
58                           ntohs(tuple->src.u.udp.port),
59                           ntohs(tuple->dst.u.udp.port));
60 }
61
62 /* Print out the private part of the conntrack. */
63 static int udp_print_conntrack(struct seq_file *s,
64                                const struct nf_conn *conntrack)
65 {
66         return 0;
67 }
68
69 /* Returns verdict for packet, and may modify conntracktype */
70 static int udp_packet(struct nf_conn *conntrack,
71                       const struct sk_buff *skb,
72                       unsigned int dataoff,
73                       enum ip_conntrack_info ctinfo,
74                       int pf,
75                       unsigned int hooknum)
76 {
77         /* If we've seen traffic both ways, this is some kind of UDP
78            stream.  Extend timeout. */
79         if (test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)) {
80                 nf_ct_refresh_acct(conntrack, ctinfo, skb,
81                                    nf_ct_udp_timeout_stream);
82                 /* Also, more likely to be important, and not a probe */
83                 if (!test_and_set_bit(IPS_ASSURED_BIT, &conntrack->status))
84                         nf_conntrack_event_cache(IPCT_STATUS, skb);
85         } else
86                 nf_ct_refresh_acct(conntrack, ctinfo, skb, nf_ct_udp_timeout);
87
88         return NF_ACCEPT;
89 }
90
91 /* Called when a new connection for this protocol found. */
92 static int udp_new(struct nf_conn *conntrack, const struct sk_buff *skb,
93                    unsigned int dataoff)
94 {
95         return 1;
96 }
97
98 static int udp_error(struct sk_buff *skb, unsigned int dataoff,
99                      enum ip_conntrack_info *ctinfo,
100                      int pf,
101                      unsigned int hooknum)
102 {
103         unsigned int udplen = skb->len - dataoff;
104         struct udphdr _hdr, *hdr;
105
106         /* Header is too small? */
107         hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
108         if (hdr == NULL) {
109                 if (LOG_INVALID(IPPROTO_UDP))
110                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
111                                       "nf_ct_udp: short packet ");
112                 return -NF_ACCEPT;
113         }
114
115         /* Truncated/malformed packets */
116         if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) {
117                 if (LOG_INVALID(IPPROTO_UDP))
118                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
119                                 "nf_ct_udp: truncated/malformed packet ");
120                 return -NF_ACCEPT;
121         }
122
123         /* Packet with no checksum */
124         if (!hdr->check)
125                 return NF_ACCEPT;
126
127         /* Checksum invalid? Ignore.
128          * We skip checking packets on the outgoing path
129          * because the checksum is assumed to be correct.
130          * FIXME: Source route IP option packets --RR */
131         if (nf_conntrack_checksum &&
132             ((pf == PF_INET && hooknum == NF_IP_PRE_ROUTING) ||
133              (pf == PF_INET6 && hooknum == NF_IP6_PRE_ROUTING)) &&
134             nf_checksum(skb, hooknum, dataoff, IPPROTO_UDP, pf)) {
135                 if (LOG_INVALID(IPPROTO_UDP))
136                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
137                                 "nf_ct_udp: bad UDP checksum ");
138                 return -NF_ACCEPT;
139         }
140
141         return NF_ACCEPT;
142 }
143
144 #ifdef CONFIG_SYSCTL
145 static unsigned int udp_sysctl_table_users;
146 static struct ctl_table_header *udp_sysctl_header;
147 static struct ctl_table udp_sysctl_table[] = {
148         {
149                 .ctl_name       = NET_NF_CONNTRACK_UDP_TIMEOUT,
150                 .procname       = "nf_conntrack_udp_timeout",
151                 .data           = &nf_ct_udp_timeout,
152                 .maxlen         = sizeof(unsigned int),
153                 .mode           = 0644,
154                 .proc_handler   = &proc_dointvec_jiffies,
155         },
156         {
157                 .ctl_name       = NET_NF_CONNTRACK_UDP_TIMEOUT_STREAM,
158                 .procname       = "nf_conntrack_udp_timeout_stream",
159                 .data           = &nf_ct_udp_timeout_stream,
160                 .maxlen         = sizeof(unsigned int),
161                 .mode           = 0644,
162                 .proc_handler   = &proc_dointvec_jiffies,
163         },
164         {
165                 .ctl_name       = 0
166         }
167 };
168 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
169 static struct ctl_table udp_compat_sysctl_table[] = {
170         {
171                 .ctl_name       = NET_IPV4_NF_CONNTRACK_UDP_TIMEOUT,
172                 .procname       = "ip_conntrack_udp_timeout",
173                 .data           = &nf_ct_udp_timeout,
174                 .maxlen         = sizeof(unsigned int),
175                 .mode           = 0644,
176                 .proc_handler   = &proc_dointvec_jiffies,
177         },
178         {
179                 .ctl_name       = NET_IPV4_NF_CONNTRACK_UDP_TIMEOUT_STREAM,
180                 .procname       = "ip_conntrack_udp_timeout_stream",
181                 .data           = &nf_ct_udp_timeout_stream,
182                 .maxlen         = sizeof(unsigned int),
183                 .mode           = 0644,
184                 .proc_handler   = &proc_dointvec_jiffies,
185         },
186         {
187                 .ctl_name       = 0
188         }
189 };
190 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
191 #endif /* CONFIG_SYSCTL */
192
193 struct nf_conntrack_l4proto nf_conntrack_l4proto_udp4 __read_mostly =
194 {
195         .l3proto                = PF_INET,
196         .l4proto                = IPPROTO_UDP,
197         .name                   = "udp",
198         .pkt_to_tuple           = udp_pkt_to_tuple,
199         .invert_tuple           = udp_invert_tuple,
200         .print_tuple            = udp_print_tuple,
201         .print_conntrack        = udp_print_conntrack,
202         .packet                 = udp_packet,
203         .new                    = udp_new,
204         .error                  = udp_error,
205 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
206         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
207         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
208         .nla_policy             = nf_ct_port_nla_policy,
209 #endif
210 #ifdef CONFIG_SYSCTL
211         .ctl_table_users        = &udp_sysctl_table_users,
212         .ctl_table_header       = &udp_sysctl_header,
213         .ctl_table              = udp_sysctl_table,
214 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
215         .ctl_compat_table       = udp_compat_sysctl_table,
216 #endif
217 #endif
218 };
219 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp4);
220
221 struct nf_conntrack_l4proto nf_conntrack_l4proto_udp6 __read_mostly =
222 {
223         .l3proto                = PF_INET6,
224         .l4proto                = IPPROTO_UDP,
225         .name                   = "udp",
226         .pkt_to_tuple           = udp_pkt_to_tuple,
227         .invert_tuple           = udp_invert_tuple,
228         .print_tuple            = udp_print_tuple,
229         .print_conntrack        = udp_print_conntrack,
230         .packet                 = udp_packet,
231         .new                    = udp_new,
232         .error                  = udp_error,
233 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
234         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
235         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
236         .nla_policy             = nf_ct_port_nla_policy,
237 #endif
238 #ifdef CONFIG_SYSCTL
239         .ctl_table_users        = &udp_sysctl_table_users,
240         .ctl_table_header       = &udp_sysctl_header,
241         .ctl_table              = udp_sysctl_table,
242 #endif
243 };
244 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp6);