[NETFILTER]: nf_conntrack: move conntrack protocol sysctls to individual modules
[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  * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
9  *      - enable working with Layer 3 protocol independent connection tracking.
10  *
11  * Derived from net/ipv4/netfilter/ip_conntrack_proto_udp.c
12  */
13
14 #include <linux/types.h>
15 #include <linux/sched.h>
16 #include <linux/timer.h>
17 #include <linux/module.h>
18 #include <linux/netfilter.h>
19 #include <linux/udp.h>
20 #include <linux/seq_file.h>
21 #include <linux/skbuff.h>
22 #include <linux/ipv6.h>
23 #include <net/ip6_checksum.h>
24 #include <net/checksum.h>
25
26 #include <linux/netfilter.h>
27 #include <linux/netfilter_ipv4.h>
28 #include <linux/netfilter_ipv6.h>
29 #include <net/netfilter/nf_conntrack_l4proto.h>
30 #include <net/netfilter/nf_conntrack_ecache.h>
31
32 static unsigned int nf_ct_udp_timeout __read_mostly = 30*HZ;
33 static unsigned int nf_ct_udp_timeout_stream __read_mostly = 180*HZ;
34
35 static int udp_pkt_to_tuple(const struct sk_buff *skb,
36                              unsigned int dataoff,
37                              struct nf_conntrack_tuple *tuple)
38 {
39         struct udphdr _hdr, *hp;
40
41         /* Actually only need first 8 bytes. */
42         hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
43         if (hp == NULL)
44                 return 0;
45
46         tuple->src.u.udp.port = hp->source;
47         tuple->dst.u.udp.port = hp->dest;
48
49         return 1;
50 }
51
52 static int udp_invert_tuple(struct nf_conntrack_tuple *tuple,
53                             const struct nf_conntrack_tuple *orig)
54 {
55         tuple->src.u.udp.port = orig->dst.u.udp.port;
56         tuple->dst.u.udp.port = orig->src.u.udp.port;
57         return 1;
58 }
59
60 /* Print out the per-protocol part of the tuple. */
61 static int udp_print_tuple(struct seq_file *s,
62                            const struct nf_conntrack_tuple *tuple)
63 {
64         return seq_printf(s, "sport=%hu dport=%hu ",
65                           ntohs(tuple->src.u.udp.port),
66                           ntohs(tuple->dst.u.udp.port));
67 }
68
69 /* Print out the private part of the conntrack. */
70 static int udp_print_conntrack(struct seq_file *s,
71                                const struct nf_conn *conntrack)
72 {
73         return 0;
74 }
75
76 /* Returns verdict for packet, and may modify conntracktype */
77 static int udp_packet(struct nf_conn *conntrack,
78                       const struct sk_buff *skb,
79                       unsigned int dataoff,
80                       enum ip_conntrack_info ctinfo,
81                       int pf,
82                       unsigned int hooknum)
83 {
84         /* If we've seen traffic both ways, this is some kind of UDP
85            stream.  Extend timeout. */
86         if (test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)) {
87                 nf_ct_refresh_acct(conntrack, ctinfo, skb,
88                                    nf_ct_udp_timeout_stream);
89                 /* Also, more likely to be important, and not a probe */
90                 if (!test_and_set_bit(IPS_ASSURED_BIT, &conntrack->status))
91                         nf_conntrack_event_cache(IPCT_STATUS, skb);
92         } else
93                 nf_ct_refresh_acct(conntrack, ctinfo, skb, nf_ct_udp_timeout);
94
95         return NF_ACCEPT;
96 }
97
98 /* Called when a new connection for this protocol found. */
99 static int udp_new(struct nf_conn *conntrack, const struct sk_buff *skb,
100                    unsigned int dataoff)
101 {
102         return 1;
103 }
104
105 static int udp_error(struct sk_buff *skb, unsigned int dataoff,
106                      enum ip_conntrack_info *ctinfo,
107                      int pf,
108                      unsigned int hooknum)
109 {
110         unsigned int udplen = skb->len - dataoff;
111         struct udphdr _hdr, *hdr;
112
113         /* Header is too small? */
114         hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
115         if (hdr == NULL) {
116                 if (LOG_INVALID(IPPROTO_UDP))
117                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
118                                       "nf_ct_udp: short packet ");
119                 return -NF_ACCEPT;
120         }
121
122         /* Truncated/malformed packets */
123         if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) {
124                 if (LOG_INVALID(IPPROTO_UDP))
125                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
126                                 "nf_ct_udp: truncated/malformed packet ");
127                 return -NF_ACCEPT;
128         }
129
130         /* Packet with no checksum */
131         if (!hdr->check)
132                 return NF_ACCEPT;
133
134         /* Checksum invalid? Ignore.
135          * We skip checking packets on the outgoing path
136          * because the checksum is assumed to be correct.
137          * FIXME: Source route IP option packets --RR */
138         if (nf_conntrack_checksum &&
139             ((pf == PF_INET && hooknum == NF_IP_PRE_ROUTING) ||
140              (pf == PF_INET6 && hooknum == NF_IP6_PRE_ROUTING)) &&
141             nf_checksum(skb, hooknum, dataoff, IPPROTO_UDP, pf)) {
142                 if (LOG_INVALID(IPPROTO_UDP))
143                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
144                                 "nf_ct_udp: bad UDP checksum ");
145                 return -NF_ACCEPT;
146         }
147
148         return NF_ACCEPT;
149 }
150
151 #ifdef CONFIG_SYSCTL
152 static unsigned int udp_sysctl_table_users;
153 static struct ctl_table_header *udp_sysctl_header;
154 static struct ctl_table udp_sysctl_table[] = {
155         {
156                 .ctl_name       = NET_NF_CONNTRACK_UDP_TIMEOUT,
157                 .procname       = "nf_conntrack_udp_timeout",
158                 .data           = &nf_ct_udp_timeout,
159                 .maxlen         = sizeof(unsigned int),
160                 .mode           = 0644,
161                 .proc_handler   = &proc_dointvec_jiffies,
162         },
163         {
164                 .ctl_name       = NET_NF_CONNTRACK_UDP_TIMEOUT_STREAM,
165                 .procname       = "nf_conntrack_udp_timeout_stream",
166                 .data           = &nf_ct_udp_timeout_stream,
167                 .maxlen         = sizeof(unsigned int),
168                 .mode           = 0644,
169                 .proc_handler   = &proc_dointvec_jiffies,
170         },
171         {
172                 .ctl_name       = 0
173         }
174 };
175 #endif /* CONFIG_SYSCTL */
176
177 struct nf_conntrack_l4proto nf_conntrack_l4proto_udp4 =
178 {
179         .l3proto                = PF_INET,
180         .l4proto                = IPPROTO_UDP,
181         .name                   = "udp",
182         .pkt_to_tuple           = udp_pkt_to_tuple,
183         .invert_tuple           = udp_invert_tuple,
184         .print_tuple            = udp_print_tuple,
185         .print_conntrack        = udp_print_conntrack,
186         .packet                 = udp_packet,
187         .new                    = udp_new,
188         .error                  = udp_error,
189 #if defined(CONFIG_NF_CT_NETLINK) || \
190     defined(CONFIG_NF_CT_NETLINK_MODULE)
191         .tuple_to_nfattr        = nf_ct_port_tuple_to_nfattr,
192         .nfattr_to_tuple        = nf_ct_port_nfattr_to_tuple,
193 #endif
194 #ifdef CONFIG_SYSCTL
195         .ctl_table_users        = &udp_sysctl_table_users,
196         .ctl_table_header       = &udp_sysctl_header,
197         .ctl_table              = udp_sysctl_table,
198 #endif
199 };
200
201 struct nf_conntrack_l4proto nf_conntrack_l4proto_udp6 =
202 {
203         .l3proto                = PF_INET6,
204         .l4proto                = IPPROTO_UDP,
205         .name                   = "udp",
206         .pkt_to_tuple           = udp_pkt_to_tuple,
207         .invert_tuple           = udp_invert_tuple,
208         .print_tuple            = udp_print_tuple,
209         .print_conntrack        = udp_print_conntrack,
210         .packet                 = udp_packet,
211         .new                    = udp_new,
212         .error                  = udp_error,
213 #if defined(CONFIG_NF_CT_NETLINK) || \
214     defined(CONFIG_NF_CT_NETLINK_MODULE)
215         .tuple_to_nfattr        = nf_ct_port_tuple_to_nfattr,
216         .nfattr_to_tuple        = nf_ct_port_nfattr_to_tuple,
217 #endif
218 #ifdef CONFIG_SYSCTL
219         .ctl_table_users        = &udp_sysctl_table_users,
220         .ctl_table_header       = &udp_sysctl_header,
221         .ctl_table              = udp_sysctl_table,
222 #endif
223 };
224
225 EXPORT_SYMBOL(nf_conntrack_l4proto_udp4);
226 EXPORT_SYMBOL(nf_conntrack_l4proto_udp6);