mqprio: Avoid panic if no options are provided
[linux-2.6.git] / net / netfilter / nf_conntrack_proto_udplite.c
1 /* (C) 1999-2001 Paul `Rusty' Russell
2  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
3  * (C) 2007 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
27 static unsigned int nf_ct_udplite_timeout __read_mostly = 30*HZ;
28 static unsigned int nf_ct_udplite_timeout_stream __read_mostly = 180*HZ;
29
30 static bool udplite_pkt_to_tuple(const struct sk_buff *skb,
31                                  unsigned int dataoff,
32                                  struct nf_conntrack_tuple *tuple)
33 {
34         const struct udphdr *hp;
35         struct udphdr _hdr;
36
37         hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
38         if (hp == NULL)
39                 return false;
40
41         tuple->src.u.udp.port = hp->source;
42         tuple->dst.u.udp.port = hp->dest;
43         return true;
44 }
45
46 static bool udplite_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 true;
52 }
53
54 /* Print out the per-protocol part of the tuple. */
55 static int udplite_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 udplite_packet(struct nf_conn *ct,
65                           const struct sk_buff *skb,
66                           unsigned int dataoff,
67                           enum ip_conntrack_info ctinfo,
68                           u_int8_t 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, &ct->status)) {
74                 nf_ct_refresh_acct(ct, ctinfo, skb,
75                                    nf_ct_udplite_timeout_stream);
76                 /* Also, more likely to be important, and not a probe */
77                 if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
78                         nf_conntrack_event_cache(IPCT_ASSURED, ct);
79         } else
80                 nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_udplite_timeout);
81
82         return NF_ACCEPT;
83 }
84
85 /* Called when a new connection for this protocol found. */
86 static bool udplite_new(struct nf_conn *ct, const struct sk_buff *skb,
87                         unsigned int dataoff)
88 {
89         return true;
90 }
91
92 static int udplite_error(struct net *net, struct nf_conn *tmpl,
93                          struct sk_buff *skb,
94                          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         unsigned int cscov;
103
104         /* Header is too small? */
105         hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
106         if (hdr == NULL) {
107                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
108                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
109                                       "nf_ct_udplite: short packet ");
110                 return -NF_ACCEPT;
111         }
112
113         cscov = ntohs(hdr->len);
114         if (cscov == 0)
115                 cscov = udplen;
116         else if (cscov < sizeof(*hdr) || cscov > udplen) {
117                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
118                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
119                                 "nf_ct_udplite: invalid checksum coverage ");
120                 return -NF_ACCEPT;
121         }
122
123         /* UDPLITE mandates checksums */
124         if (!hdr->check) {
125                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
126                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
127                                       "nf_ct_udplite: checksum missing ");
128                 return -NF_ACCEPT;
129         }
130
131         /* Checksum invalid? Ignore. */
132         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
133             nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_UDP,
134                                 pf)) {
135                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
136                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
137                                       "nf_ct_udplite: bad UDPLite checksum ");
138                 return -NF_ACCEPT;
139         }
140
141         return NF_ACCEPT;
142 }
143
144 #ifdef CONFIG_SYSCTL
145 static unsigned int udplite_sysctl_table_users;
146 static struct ctl_table_header *udplite_sysctl_header;
147 static struct ctl_table udplite_sysctl_table[] = {
148         {
149                 .procname       = "nf_conntrack_udplite_timeout",
150                 .data           = &nf_ct_udplite_timeout,
151                 .maxlen         = sizeof(unsigned int),
152                 .mode           = 0644,
153                 .proc_handler   = proc_dointvec_jiffies,
154         },
155         {
156                 .procname       = "nf_conntrack_udplite_timeout_stream",
157                 .data           = &nf_ct_udplite_timeout_stream,
158                 .maxlen         = sizeof(unsigned int),
159                 .mode           = 0644,
160                 .proc_handler   = proc_dointvec_jiffies,
161         },
162         { }
163 };
164 #endif /* CONFIG_SYSCTL */
165
166 static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite4 __read_mostly =
167 {
168         .l3proto                = PF_INET,
169         .l4proto                = IPPROTO_UDPLITE,
170         .name                   = "udplite",
171         .pkt_to_tuple           = udplite_pkt_to_tuple,
172         .invert_tuple           = udplite_invert_tuple,
173         .print_tuple            = udplite_print_tuple,
174         .packet                 = udplite_packet,
175         .new                    = udplite_new,
176         .error                  = udplite_error,
177 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
178         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
179         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
180         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
181         .nla_policy             = nf_ct_port_nla_policy,
182 #endif
183 #ifdef CONFIG_SYSCTL
184         .ctl_table_users        = &udplite_sysctl_table_users,
185         .ctl_table_header       = &udplite_sysctl_header,
186         .ctl_table              = udplite_sysctl_table,
187 #endif
188 };
189
190 static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite6 __read_mostly =
191 {
192         .l3proto                = PF_INET6,
193         .l4proto                = IPPROTO_UDPLITE,
194         .name                   = "udplite",
195         .pkt_to_tuple           = udplite_pkt_to_tuple,
196         .invert_tuple           = udplite_invert_tuple,
197         .print_tuple            = udplite_print_tuple,
198         .packet                 = udplite_packet,
199         .new                    = udplite_new,
200         .error                  = udplite_error,
201 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
202         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
203         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
204         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
205         .nla_policy             = nf_ct_port_nla_policy,
206 #endif
207 #ifdef CONFIG_SYSCTL
208         .ctl_table_users        = &udplite_sysctl_table_users,
209         .ctl_table_header       = &udplite_sysctl_header,
210         .ctl_table              = udplite_sysctl_table,
211 #endif
212 };
213
214 static int __init nf_conntrack_proto_udplite_init(void)
215 {
216         int err;
217
218         err = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udplite4);
219         if (err < 0)
220                 goto err1;
221         err = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udplite6);
222         if (err < 0)
223                 goto err2;
224         return 0;
225 err2:
226         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
227 err1:
228         return err;
229 }
230
231 static void __exit nf_conntrack_proto_udplite_exit(void)
232 {
233         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite6);
234         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
235 }
236
237 module_init(nf_conntrack_proto_udplite_init);
238 module_exit(nf_conntrack_proto_udplite_exit);
239
240 MODULE_LICENSE("GPL");