243 lines
6.7 KiB
C
243 lines
6.7 KiB
C
/* (C) 1999-2001 Paul `Rusty' Russell
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* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
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* (C) 2007 Patrick McHardy <kaber@trash.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/types.h>
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#include <linux/timer.h>
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#include <linux/module.h>
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#include <linux/udp.h>
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#include <linux/seq_file.h>
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#include <linux/skbuff.h>
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#include <linux/ipv6.h>
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#include <net/ip6_checksum.h>
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#include <net/checksum.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter_ipv4.h>
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#include <linux/netfilter_ipv6.h>
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#include <net/netfilter/nf_conntrack_l4proto.h>
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#include <net/netfilter/nf_conntrack_ecache.h>
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#include <net/netfilter/nf_log.h>
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static unsigned int nf_ct_udplite_timeout __read_mostly = 30*HZ;
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static unsigned int nf_ct_udplite_timeout_stream __read_mostly = 180*HZ;
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static bool udplite_pkt_to_tuple(const struct sk_buff *skb,
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unsigned int dataoff,
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struct nf_conntrack_tuple *tuple)
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{
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const struct udphdr *hp;
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struct udphdr _hdr;
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hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
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if (hp == NULL)
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return false;
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tuple->src.u.udp.port = hp->source;
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tuple->dst.u.udp.port = hp->dest;
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return true;
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}
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static bool udplite_invert_tuple(struct nf_conntrack_tuple *tuple,
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const struct nf_conntrack_tuple *orig)
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{
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tuple->src.u.udp.port = orig->dst.u.udp.port;
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tuple->dst.u.udp.port = orig->src.u.udp.port;
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return true;
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}
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/* Print out the per-protocol part of the tuple. */
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static int udplite_print_tuple(struct seq_file *s,
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const struct nf_conntrack_tuple *tuple)
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{
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return seq_printf(s, "sport=%hu dport=%hu ",
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ntohs(tuple->src.u.udp.port),
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ntohs(tuple->dst.u.udp.port));
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}
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/* Returns verdict for packet, and may modify conntracktype */
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static int udplite_packet(struct nf_conn *ct,
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const struct sk_buff *skb,
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unsigned int dataoff,
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enum ip_conntrack_info ctinfo,
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u_int8_t pf,
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unsigned int hooknum)
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{
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/* If we've seen traffic both ways, this is some kind of UDP
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stream. Extend timeout. */
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if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
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nf_ct_refresh_acct(ct, ctinfo, skb,
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nf_ct_udplite_timeout_stream);
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/* Also, more likely to be important, and not a probe */
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if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
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nf_conntrack_event_cache(IPCT_STATUS, ct);
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} else
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nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_udplite_timeout);
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return NF_ACCEPT;
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}
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/* Called when a new connection for this protocol found. */
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static bool udplite_new(struct nf_conn *ct, const struct sk_buff *skb,
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unsigned int dataoff)
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{
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return true;
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}
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static int udplite_error(struct net *net,
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struct sk_buff *skb,
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unsigned int dataoff,
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enum ip_conntrack_info *ctinfo,
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u_int8_t pf,
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unsigned int hooknum)
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{
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unsigned int udplen = skb->len - dataoff;
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const struct udphdr *hdr;
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struct udphdr _hdr;
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unsigned int cscov;
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/* Header is too small? */
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hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
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if (hdr == NULL) {
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if (LOG_INVALID(IPPROTO_UDPLITE))
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nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
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"nf_ct_udplite: short packet ");
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return -NF_ACCEPT;
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}
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cscov = ntohs(hdr->len);
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if (cscov == 0)
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cscov = udplen;
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else if (cscov < sizeof(*hdr) || cscov > udplen) {
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if (LOG_INVALID(IPPROTO_UDPLITE))
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nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
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"nf_ct_udplite: invalid checksum coverage ");
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return -NF_ACCEPT;
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}
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/* UDPLITE mandates checksums */
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if (!hdr->check) {
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if (LOG_INVALID(IPPROTO_UDPLITE))
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nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
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"nf_ct_udplite: checksum missing ");
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return -NF_ACCEPT;
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}
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/* Checksum invalid? Ignore. */
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if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
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nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_UDP,
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pf)) {
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if (LOG_INVALID(IPPROTO_UDPLITE))
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nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
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"nf_ct_udplite: bad UDPLite checksum ");
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return -NF_ACCEPT;
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}
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return NF_ACCEPT;
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}
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#ifdef CONFIG_SYSCTL
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static unsigned int udplite_sysctl_table_users;
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static struct ctl_table_header *udplite_sysctl_header;
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static struct ctl_table udplite_sysctl_table[] = {
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{
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.ctl_name = CTL_UNNUMBERED,
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.procname = "nf_conntrack_udplite_timeout",
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.data = &nf_ct_udplite_timeout,
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.maxlen = sizeof(unsigned int),
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.mode = 0644,
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.proc_handler = &proc_dointvec_jiffies,
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},
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{
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.ctl_name = CTL_UNNUMBERED,
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.procname = "nf_conntrack_udplite_timeout_stream",
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.data = &nf_ct_udplite_timeout_stream,
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.maxlen = sizeof(unsigned int),
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.mode = 0644,
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.proc_handler = &proc_dointvec_jiffies,
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},
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{
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.ctl_name = 0
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}
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};
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#endif /* CONFIG_SYSCTL */
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static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite4 __read_mostly =
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{
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.l3proto = PF_INET,
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.l4proto = IPPROTO_UDPLITE,
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.name = "udplite",
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.pkt_to_tuple = udplite_pkt_to_tuple,
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.invert_tuple = udplite_invert_tuple,
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.print_tuple = udplite_print_tuple,
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.packet = udplite_packet,
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.new = udplite_new,
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.error = udplite_error,
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#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
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.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
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.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
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.nla_policy = nf_ct_port_nla_policy,
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#endif
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#ifdef CONFIG_SYSCTL
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.ctl_table_users = &udplite_sysctl_table_users,
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.ctl_table_header = &udplite_sysctl_header,
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.ctl_table = udplite_sysctl_table,
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#endif
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};
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static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite6 __read_mostly =
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{
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.l3proto = PF_INET6,
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.l4proto = IPPROTO_UDPLITE,
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.name = "udplite",
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.pkt_to_tuple = udplite_pkt_to_tuple,
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.invert_tuple = udplite_invert_tuple,
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.print_tuple = udplite_print_tuple,
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.packet = udplite_packet,
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.new = udplite_new,
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.error = udplite_error,
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#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
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.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
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.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
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.nla_policy = nf_ct_port_nla_policy,
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#endif
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#ifdef CONFIG_SYSCTL
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.ctl_table_users = &udplite_sysctl_table_users,
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.ctl_table_header = &udplite_sysctl_header,
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.ctl_table = udplite_sysctl_table,
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#endif
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};
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static int __init nf_conntrack_proto_udplite_init(void)
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{
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int err;
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err = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udplite4);
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if (err < 0)
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goto err1;
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err = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udplite6);
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if (err < 0)
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goto err2;
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return 0;
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err2:
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nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
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err1:
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return err;
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}
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static void __exit nf_conntrack_proto_udplite_exit(void)
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{
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nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite6);
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nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
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}
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module_init(nf_conntrack_proto_udplite_init);
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module_exit(nf_conntrack_proto_udplite_exit);
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MODULE_LICENSE("GPL");
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