1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
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.
9 #include <linux/types.h>
10 #include <linux/sched.h>
11 #include <linux/timer.h>
12 #include <linux/netfilter.h>
15 #include <linux/udp.h>
16 #include <linux/seq_file.h>
17 #include <net/checksum.h>
18 #include <linux/netfilter.h>
19 #include <linux/netfilter_ipv4.h>
20 #include <linux/netfilter_ipv4/ip_conntrack_protocol.h>
22 unsigned long ip_ct_udp_timeout = 30*HZ;
23 unsigned long ip_ct_udp_timeout_stream = 180*HZ;
25 static int udp_pkt_to_tuple(const struct sk_buff *skb,
27 struct ip_conntrack_tuple *tuple)
29 struct udphdr _hdr, *hp;
31 /* Actually only need first 8 bytes. */
32 hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
36 tuple->src.u.udp.port = hp->source;
37 tuple->dst.u.udp.port = hp->dest;
42 static int udp_invert_tuple(struct ip_conntrack_tuple *tuple,
43 const struct ip_conntrack_tuple *orig)
45 tuple->src.u.udp.port = orig->dst.u.udp.port;
46 tuple->dst.u.udp.port = orig->src.u.udp.port;
50 /* Print out the per-protocol part of the tuple. */
51 static int udp_print_tuple(struct seq_file *s,
52 const struct ip_conntrack_tuple *tuple)
54 return seq_printf(s, "sport=%hu dport=%hu ",
55 ntohs(tuple->src.u.udp.port),
56 ntohs(tuple->dst.u.udp.port));
59 /* Print out the private part of the conntrack. */
60 static int udp_print_conntrack(struct seq_file *s,
61 const struct ip_conntrack *conntrack)
66 /* Returns verdict for packet, and may modify conntracktype */
67 static int udp_packet(struct ip_conntrack *conntrack,
68 const struct sk_buff *skb,
69 enum ip_conntrack_info ctinfo)
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 ip_ct_refresh_acct(conntrack, ctinfo, skb,
75 ip_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 ip_conntrack_event_cache(IPCT_STATUS, skb);
80 ip_ct_refresh_acct(conntrack, ctinfo, skb, ip_ct_udp_timeout);
85 /* Called when a new connection for this protocol found. */
86 static int udp_new(struct ip_conntrack *conntrack, const struct sk_buff *skb)
91 static int udp_error(struct sk_buff *skb, enum ip_conntrack_info *ctinfo,
94 struct iphdr *iph = skb->nh.iph;
95 unsigned int udplen = skb->len - iph->ihl * 4;
96 struct udphdr _hdr, *hdr;
98 /* Header is too small? */
99 hdr = skb_header_pointer(skb, iph->ihl*4, sizeof(_hdr), &_hdr);
101 if (LOG_INVALID(IPPROTO_UDP))
102 nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
103 "ip_ct_udp: short packet ");
107 /* Truncated/malformed packets */
108 if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) {
109 if (LOG_INVALID(IPPROTO_UDP))
110 nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
111 "ip_ct_udp: truncated/malformed packet ");
115 /* Packet with no checksum */
119 /* Checksum invalid? Ignore.
120 * We skip checking packets on the outgoing path
121 * because the semantic of CHECKSUM_HW is different there
122 * and moreover root might send raw packets.
123 * FIXME: Source route IP option packets --RR */
124 if (hooknum == NF_IP_PRE_ROUTING
125 && skb->ip_summed != CHECKSUM_UNNECESSARY
126 && csum_tcpudp_magic(iph->saddr, iph->daddr, udplen, IPPROTO_UDP,
127 skb->ip_summed == CHECKSUM_HW ? skb->csum
128 : skb_checksum(skb, iph->ihl*4, udplen, 0))) {
129 if (LOG_INVALID(IPPROTO_UDP))
130 nf_log_packet(PF_INET, 0, skb, NULL, NULL, NULL,
131 "ip_ct_udp: bad UDP checksum ");
138 struct ip_conntrack_protocol ip_conntrack_protocol_udp =
140 .proto = IPPROTO_UDP,
142 .pkt_to_tuple = udp_pkt_to_tuple,
143 .invert_tuple = udp_invert_tuple,
144 .print_tuple = udp_print_tuple,
145 .print_conntrack = udp_print_conntrack,
146 .packet = udp_packet,
149 #if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
150 defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
151 .tuple_to_nfattr = ip_ct_port_tuple_to_nfattr,
152 .nfattr_to_tuple = ip_ct_port_nfattr_to_tuple,