netfilter: nf_conntrack: calculate per-protocol nlattr size
[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 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
26 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
27
28 static unsigned int nf_ct_udp_timeout __read_mostly = 30*HZ;
29 static unsigned int nf_ct_udp_timeout_stream __read_mostly = 180*HZ;
30
31 static bool udp_pkt_to_tuple(const struct sk_buff *skb,
32                              unsigned int dataoff,
33                              struct nf_conntrack_tuple *tuple)
34 {
35         const struct udphdr *hp;
36         struct udphdr _hdr;
37
38         /* Actually only need first 8 bytes. */
39         hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
40         if (hp == NULL)
41                 return false;
42
43         tuple->src.u.udp.port = hp->source;
44         tuple->dst.u.udp.port = hp->dest;
45
46         return true;
47 }
48
49 static bool udp_invert_tuple(struct nf_conntrack_tuple *tuple,
50                              const struct nf_conntrack_tuple *orig)
51 {
52         tuple->src.u.udp.port = orig->dst.u.udp.port;
53         tuple->dst.u.udp.port = orig->src.u.udp.port;
54         return true;
55 }
56
57 /* Print out the per-protocol part of the tuple. */
58 static int udp_print_tuple(struct seq_file *s,
59                            const struct nf_conntrack_tuple *tuple)
60 {
61         return seq_printf(s, "sport=%hu dport=%hu ",
62                           ntohs(tuple->src.u.udp.port),
63                           ntohs(tuple->dst.u.udp.port));
64 }
65
66 /* Returns verdict for packet, and may modify conntracktype */
67 static int udp_packet(struct nf_conn *ct,
68                       const struct sk_buff *skb,
69                       unsigned int dataoff,
70                       enum ip_conntrack_info ctinfo,
71                       u_int8_t pf,
72                       unsigned int hooknum)
73 {
74         /* If we've seen traffic both ways, this is some kind of UDP
75            stream.  Extend timeout. */
76         if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
77                 nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_udp_timeout_stream);
78                 /* Also, more likely to be important, and not a probe */
79                 if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
80                         nf_conntrack_event_cache(IPCT_STATUS, ct);
81         } else
82                 nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_udp_timeout);
83
84         return NF_ACCEPT;
85 }
86
87 /* Called when a new connection for this protocol found. */
88 static bool udp_new(struct nf_conn *ct, const struct sk_buff *skb,
89                     unsigned int dataoff)
90 {
91         return true;
92 }
93
94 static int udp_error(struct net *net, struct sk_buff *skb, unsigned int dataoff,
95                      enum ip_conntrack_info *ctinfo,
96                      u_int8_t pf,
97                      unsigned int hooknum)
98 {
99         unsigned int udplen = skb->len - dataoff;
100         const struct udphdr *hdr;
101         struct udphdr _hdr;
102
103         /* Header is too small? */
104         hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
105         if (hdr == NULL) {
106                 if (LOG_INVALID(net, IPPROTO_UDP))
107                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
108                                       "nf_ct_udp: short packet ");
109                 return -NF_ACCEPT;
110         }
111
112         /* Truncated/malformed packets */
113         if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) {
114                 if (LOG_INVALID(net, IPPROTO_UDP))
115                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
116                                 "nf_ct_udp: truncated/malformed packet ");
117                 return -NF_ACCEPT;
118         }
119
120         /* Packet with no checksum */
121         if (!hdr->check)
122                 return NF_ACCEPT;
123
124         /* Checksum invalid? Ignore.
125          * We skip checking packets on the outgoing path
126          * because the checksum is assumed to be correct.
127          * FIXME: Source route IP option packets --RR */
128         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
129             nf_checksum(skb, hooknum, dataoff, IPPROTO_UDP, pf)) {
130                 if (LOG_INVALID(net, IPPROTO_UDP))
131                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
132                                 "nf_ct_udp: bad UDP checksum ");
133                 return -NF_ACCEPT;
134         }
135
136         return NF_ACCEPT;
137 }
138
139 #ifdef CONFIG_SYSCTL
140 static unsigned int udp_sysctl_table_users;
141 static struct ctl_table_header *udp_sysctl_header;
142 static struct ctl_table udp_sysctl_table[] = {
143         {
144                 .procname       = "nf_conntrack_udp_timeout",
145                 .data           = &nf_ct_udp_timeout,
146                 .maxlen         = sizeof(unsigned int),
147                 .mode           = 0644,
148                 .proc_handler   = proc_dointvec_jiffies,
149         },
150         {
151                 .procname       = "nf_conntrack_udp_timeout_stream",
152                 .data           = &nf_ct_udp_timeout_stream,
153                 .maxlen         = sizeof(unsigned int),
154                 .mode           = 0644,
155                 .proc_handler   = proc_dointvec_jiffies,
156         },
157         {
158                 .ctl_name       = 0
159         }
160 };
161 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
162 static struct ctl_table udp_compat_sysctl_table[] = {
163         {
164                 .procname       = "ip_conntrack_udp_timeout",
165                 .data           = &nf_ct_udp_timeout,
166                 .maxlen         = sizeof(unsigned int),
167                 .mode           = 0644,
168                 .proc_handler   = proc_dointvec_jiffies,
169         },
170         {
171                 .procname       = "ip_conntrack_udp_timeout_stream",
172                 .data           = &nf_ct_udp_timeout_stream,
173                 .maxlen         = sizeof(unsigned int),
174                 .mode           = 0644,
175                 .proc_handler   = proc_dointvec_jiffies,
176         },
177         {
178                 .ctl_name       = 0
179         }
180 };
181 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
182 #endif /* CONFIG_SYSCTL */
183
184 struct nf_conntrack_l4proto nf_conntrack_l4proto_udp4 __read_mostly =
185 {
186         .l3proto                = PF_INET,
187         .l4proto                = IPPROTO_UDP,
188         .name                   = "udp",
189         .pkt_to_tuple           = udp_pkt_to_tuple,
190         .invert_tuple           = udp_invert_tuple,
191         .print_tuple            = udp_print_tuple,
192         .packet                 = udp_packet,
193         .new                    = udp_new,
194         .error                  = udp_error,
195 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
196         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
197         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
198         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
199         .nla_policy             = nf_ct_port_nla_policy,
200 #endif
201 #ifdef CONFIG_SYSCTL
202         .ctl_table_users        = &udp_sysctl_table_users,
203         .ctl_table_header       = &udp_sysctl_header,
204         .ctl_table              = udp_sysctl_table,
205 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
206         .ctl_compat_table       = udp_compat_sysctl_table,
207 #endif
208 #endif
209 };
210 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp4);
211
212 struct nf_conntrack_l4proto nf_conntrack_l4proto_udp6 __read_mostly =
213 {
214         .l3proto                = PF_INET6,
215         .l4proto                = IPPROTO_UDP,
216         .name                   = "udp",
217         .pkt_to_tuple           = udp_pkt_to_tuple,
218         .invert_tuple           = udp_invert_tuple,
219         .print_tuple            = udp_print_tuple,
220         .packet                 = udp_packet,
221         .new                    = udp_new,
222         .error                  = udp_error,
223 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
224         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
225         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
226         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
227         .nla_policy             = nf_ct_port_nla_policy,
228 #endif
229 #ifdef CONFIG_SYSCTL
230         .ctl_table_users        = &udp_sysctl_table_users,
231         .ctl_table_header       = &udp_sysctl_header,
232         .ctl_table              = udp_sysctl_table,
233 #endif
234 };
235 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp6);