[PATCH] remove many unneeded #includes of sched.h
[linux-2.6.git] / net / ipv4 / netfilter / ip_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/netfilter.h>
12 #include <linux/in.h>
13 #include <linux/ip.h>
14 #include <linux/udp.h>
15 #include <linux/seq_file.h>
16 #include <net/checksum.h>
17 #include <linux/netfilter_ipv4.h>
18 #include <linux/netfilter_ipv4/ip_conntrack_protocol.h>
19
20 unsigned int ip_ct_udp_timeout __read_mostly = 30*HZ;
21 unsigned int ip_ct_udp_timeout_stream __read_mostly = 180*HZ;
22
23 static int udp_pkt_to_tuple(const struct sk_buff *skb,
24                              unsigned int dataoff,
25                              struct ip_conntrack_tuple *tuple)
26 {
27         struct udphdr _hdr, *hp;
28
29         /* Actually only need first 8 bytes. */
30         hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
31         if (hp == NULL)
32                 return 0;
33
34         tuple->src.u.udp.port = hp->source;
35         tuple->dst.u.udp.port = hp->dest;
36
37         return 1;
38 }
39
40 static int udp_invert_tuple(struct ip_conntrack_tuple *tuple,
41                             const struct ip_conntrack_tuple *orig)
42 {
43         tuple->src.u.udp.port = orig->dst.u.udp.port;
44         tuple->dst.u.udp.port = orig->src.u.udp.port;
45         return 1;
46 }
47
48 /* Print out the per-protocol part of the tuple. */
49 static int udp_print_tuple(struct seq_file *s,
50                            const struct ip_conntrack_tuple *tuple)
51 {
52         return seq_printf(s, "sport=%hu dport=%hu ",
53                           ntohs(tuple->src.u.udp.port),
54                           ntohs(tuple->dst.u.udp.port));
55 }
56
57 /* Print out the private part of the conntrack. */
58 static int udp_print_conntrack(struct seq_file *s,
59                                const struct ip_conntrack *conntrack)
60 {
61         return 0;
62 }
63
64 /* Returns verdict for packet, and may modify conntracktype */
65 static int udp_packet(struct ip_conntrack *conntrack,
66                       const struct sk_buff *skb,
67                       enum ip_conntrack_info ctinfo)
68 {
69         /* If we've seen traffic both ways, this is some kind of UDP
70            stream.  Extend timeout. */
71         if (test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)) {
72                 ip_ct_refresh_acct(conntrack, ctinfo, skb,
73                                    ip_ct_udp_timeout_stream);
74                 /* Also, more likely to be important, and not a probe */
75                 if (!test_and_set_bit(IPS_ASSURED_BIT, &conntrack->status))
76                         ip_conntrack_event_cache(IPCT_STATUS, skb);
77         } else
78                 ip_ct_refresh_acct(conntrack, ctinfo, skb, ip_ct_udp_timeout);
79
80         return NF_ACCEPT;
81 }
82
83 /* Called when a new connection for this protocol found. */
84 static int udp_new(struct ip_conntrack *conntrack, const struct sk_buff *skb)
85 {
86         return 1;
87 }
88
89 static int udp_error(struct sk_buff *skb, enum ip_conntrack_info *ctinfo,
90                      unsigned int hooknum)
91 {
92         struct iphdr *iph = skb->nh.iph;
93         unsigned int udplen = skb->len - iph->ihl * 4;
94         struct udphdr _hdr, *hdr;
95
96         /* Header is too small? */
97         hdr = skb_header_pointer(skb, iph->ihl*4, sizeof(_hdr), &_hdr);
98         if (hdr == NULL) {
99                 if (LOG_INVALID(IPPROTO_UDP))
100                         nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
101                                   "ip_ct_udp: short packet ");
102                 return -NF_ACCEPT;
103         }
104
105         /* Truncated/malformed packets */
106         if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) {
107                 if (LOG_INVALID(IPPROTO_UDP))
108                         nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
109                                   "ip_ct_udp: truncated/malformed packet ");
110                 return -NF_ACCEPT;
111         }
112
113         /* Packet with no checksum */
114         if (!hdr->check)
115                 return NF_ACCEPT;
116
117         /* Checksum invalid? Ignore.
118          * We skip checking packets on the outgoing path
119          * because the checksum is assumed to be correct.
120          * FIXME: Source route IP option packets --RR */
121         if (ip_conntrack_checksum && hooknum == NF_IP_PRE_ROUTING &&
122             nf_ip_checksum(skb, hooknum, iph->ihl * 4, IPPROTO_UDP)) {
123                 if (LOG_INVALID(IPPROTO_UDP))
124                         nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
125                                   "ip_ct_udp: bad UDP checksum ");
126                 return -NF_ACCEPT;
127         }
128
129         return NF_ACCEPT;
130 }
131
132 struct ip_conntrack_protocol ip_conntrack_protocol_udp =
133 {
134         .proto                  = IPPROTO_UDP,
135         .name                   = "udp",
136         .pkt_to_tuple           = udp_pkt_to_tuple,
137         .invert_tuple           = udp_invert_tuple,
138         .print_tuple            = udp_print_tuple,
139         .print_conntrack        = udp_print_conntrack,
140         .packet                 = udp_packet,
141         .new                    = udp_new,
142         .error                  = udp_error,
143 #if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
144     defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
145         .tuple_to_nfattr        = ip_ct_port_tuple_to_nfattr,
146         .nfattr_to_tuple        = ip_ct_port_nfattr_to_tuple,
147 #endif
148 };