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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"); |