[NETFILTER]: nf_conntrack: make print_conntrack function optional for l4protos
[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 #include <net/netfilter/nf_log.h>
25
26 static unsigned int nf_ct_udp_timeout __read_mostly = 30*HZ;
27 static unsigned int nf_ct_udp_timeout_stream __read_mostly = 180*HZ;
28
29 static int udp_pkt_to_tuple(const struct sk_buff *skb,
30                              unsigned int dataoff,
31                              struct nf_conntrack_tuple *tuple)
32 {
33         struct udphdr _hdr, *hp;
34
35         /* Actually only need first 8 bytes. */
36         hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
37         if (hp == NULL)
38                 return 0;
39
40         tuple->src.u.udp.port = hp->source;
41         tuple->dst.u.udp.port = hp->dest;
42
43         return 1;
44 }
45
46 static int udp_invert_tuple(struct nf_conntrack_tuple *tuple,
47                             const struct nf_conntrack_tuple *orig)
48 {
49         tuple->src.u.udp.port = orig->dst.u.udp.port;
50         tuple->dst.u.udp.port = orig->src.u.udp.port;
51         return 1;
52 }
53
54 /* Print out the per-protocol part of the tuple. */
55 static int udp_print_tuple(struct seq_file *s,
56                            const struct nf_conntrack_tuple *tuple)
57 {
58         return seq_printf(s, "sport=%hu dport=%hu ",
59                           ntohs(tuple->src.u.udp.port),
60                           ntohs(tuple->dst.u.udp.port));
61 }
62
63 /* Returns verdict for packet, and may modify conntracktype */
64 static int udp_packet(struct nf_conn *conntrack,
65                       const struct sk_buff *skb,
66                       unsigned int dataoff,
67                       enum ip_conntrack_info ctinfo,
68                       int pf,
69                       unsigned int hooknum)
70 {
71         /* If we've seen traffic both ways, this is some kind of UDP
72            stream.  Extend timeout. */
73         if (test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)) {
74                 nf_ct_refresh_acct(conntrack, ctinfo, skb,
75                                    nf_ct_udp_timeout_stream);
76                 /* Also, more likely to be important, and not a probe */
77                 if (!test_and_set_bit(IPS_ASSURED_BIT, &conntrack->status))
78                         nf_conntrack_event_cache(IPCT_STATUS, skb);
79         } else
80                 nf_ct_refresh_acct(conntrack, ctinfo, skb, nf_ct_udp_timeout);
81
82         return NF_ACCEPT;
83 }
84
85 /* Called when a new connection for this protocol found. */
86 static int udp_new(struct nf_conn *conntrack, const struct sk_buff *skb,
87                    unsigned int dataoff)
88 {
89         return 1;
90 }
91
92 static int udp_error(struct sk_buff *skb, unsigned int dataoff,
93                      enum ip_conntrack_info *ctinfo,
94                      int pf,
95                      unsigned int hooknum)
96 {
97         unsigned int udplen = skb->len - dataoff;
98         struct udphdr _hdr, *hdr;
99
100         /* Header is too small? */
101         hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
102         if (hdr == NULL) {
103                 if (LOG_INVALID(IPPROTO_UDP))
104                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
105                                       "nf_ct_udp: short packet ");
106                 return -NF_ACCEPT;
107         }
108
109         /* Truncated/malformed packets */
110         if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) {
111                 if (LOG_INVALID(IPPROTO_UDP))
112                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
113                                 "nf_ct_udp: truncated/malformed packet ");
114                 return -NF_ACCEPT;
115         }
116
117         /* Packet with no checksum */
118         if (!hdr->check)
119                 return NF_ACCEPT;
120
121         /* Checksum invalid? Ignore.
122          * We skip checking packets on the outgoing path
123          * because the checksum is assumed to be correct.
124          * FIXME: Source route IP option packets --RR */
125         if (nf_conntrack_checksum && hooknum == NF_INET_PRE_ROUTING &&
126             nf_checksum(skb, hooknum, dataoff, IPPROTO_UDP, pf)) {
127                 if (LOG_INVALID(IPPROTO_UDP))
128                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
129                                 "nf_ct_udp: bad UDP checksum ");
130                 return -NF_ACCEPT;
131         }
132
133         return NF_ACCEPT;
134 }
135
136 #ifdef CONFIG_SYSCTL
137 static unsigned int udp_sysctl_table_users;
138 static struct ctl_table_header *udp_sysctl_header;
139 static struct ctl_table udp_sysctl_table[] = {
140         {
141                 .procname       = "nf_conntrack_udp_timeout",
142                 .data           = &nf_ct_udp_timeout,
143                 .maxlen         = sizeof(unsigned int),
144                 .mode           = 0644,
145                 .proc_handler   = &proc_dointvec_jiffies,
146         },
147         {
148                 .procname       = "nf_conntrack_udp_timeout_stream",
149                 .data           = &nf_ct_udp_timeout_stream,
150                 .maxlen         = sizeof(unsigned int),
151                 .mode           = 0644,
152                 .proc_handler   = &proc_dointvec_jiffies,
153         },
154         {
155                 .ctl_name       = 0
156         }
157 };
158 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
159 static struct ctl_table udp_compat_sysctl_table[] = {
160         {
161                 .procname       = "ip_conntrack_udp_timeout",
162                 .data           = &nf_ct_udp_timeout,
163                 .maxlen         = sizeof(unsigned int),
164                 .mode           = 0644,
165                 .proc_handler   = &proc_dointvec_jiffies,
166         },
167         {
168                 .procname       = "ip_conntrack_udp_timeout_stream",
169                 .data           = &nf_ct_udp_timeout_stream,
170                 .maxlen         = sizeof(unsigned int),
171                 .mode           = 0644,
172                 .proc_handler   = &proc_dointvec_jiffies,
173         },
174         {
175                 .ctl_name       = 0
176         }
177 };
178 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
179 #endif /* CONFIG_SYSCTL */
180
181 struct nf_conntrack_l4proto nf_conntrack_l4proto_udp4 __read_mostly =
182 {
183         .l3proto                = PF_INET,
184         .l4proto                = IPPROTO_UDP,
185         .name                   = "udp",
186         .pkt_to_tuple           = udp_pkt_to_tuple,
187         .invert_tuple           = udp_invert_tuple,
188         .print_tuple            = udp_print_tuple,
189         .packet                 = udp_packet,
190         .new                    = udp_new,
191         .error                  = udp_error,
192 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
193         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
194         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
195         .nla_policy             = nf_ct_port_nla_policy,
196 #endif
197 #ifdef CONFIG_SYSCTL
198         .ctl_table_users        = &udp_sysctl_table_users,
199         .ctl_table_header       = &udp_sysctl_header,
200         .ctl_table              = udp_sysctl_table,
201 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
202         .ctl_compat_table       = udp_compat_sysctl_table,
203 #endif
204 #endif
205 };
206 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp4);
207
208 struct nf_conntrack_l4proto nf_conntrack_l4proto_udp6 __read_mostly =
209 {
210         .l3proto                = PF_INET6,
211         .l4proto                = IPPROTO_UDP,
212         .name                   = "udp",
213         .pkt_to_tuple           = udp_pkt_to_tuple,
214         .invert_tuple           = udp_invert_tuple,
215         .print_tuple            = udp_print_tuple,
216         .packet                 = udp_packet,
217         .new                    = udp_new,
218         .error                  = udp_error,
219 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
220         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
221         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
222         .nla_policy             = nf_ct_port_nla_policy,
223 #endif
224 #ifdef CONFIG_SYSCTL
225         .ctl_table_users        = &udp_sysctl_table_users,
226         .ctl_table_header       = &udp_sysctl_header,
227         .ctl_table              = udp_sysctl_table,
228 #endif
229 };
230 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp6);