314 lines
8.8 KiB
C
314 lines
8.8 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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*
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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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#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
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#include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
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enum udp_conntrack {
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UDP_CT_UNREPLIED,
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UDP_CT_REPLIED,
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UDP_CT_MAX
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};
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static unsigned int udp_timeouts[UDP_CT_MAX] = {
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[UDP_CT_UNREPLIED] = 30*HZ,
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[UDP_CT_REPLIED] = 180*HZ,
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};
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static bool udp_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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/* Actually only need first 8 bytes. */
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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 udp_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 udp_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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static unsigned int *udp_get_timeouts(struct net *net)
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{
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return udp_timeouts;
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}
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/* Returns verdict for packet, and may modify conntracktype */
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static int udp_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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unsigned int *timeouts)
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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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timeouts[UDP_CT_REPLIED]);
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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_ASSURED, ct);
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} else {
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nf_ct_refresh_acct(ct, ctinfo, skb,
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timeouts[UDP_CT_UNREPLIED]);
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}
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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 udp_new(struct nf_conn *ct, const struct sk_buff *skb,
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unsigned int dataoff, unsigned int *timeouts)
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{
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return true;
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}
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static int udp_error(struct net *net, struct nf_conn *tmpl, struct sk_buff *skb,
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unsigned int dataoff, 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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/* 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(net, IPPROTO_UDP))
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nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
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"nf_ct_udp: short packet ");
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return -NF_ACCEPT;
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}
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/* Truncated/malformed packets */
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if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) {
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if (LOG_INVALID(net, IPPROTO_UDP))
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nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
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"nf_ct_udp: truncated/malformed packet ");
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return -NF_ACCEPT;
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}
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/* Packet with no checksum */
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if (!hdr->check)
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return NF_ACCEPT;
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/* Checksum invalid? Ignore.
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* We skip checking packets on the outgoing path
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* because the checksum is assumed to be correct.
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* FIXME: Source route IP option packets --RR */
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if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
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nf_checksum(skb, hooknum, dataoff, IPPROTO_UDP, pf)) {
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if (LOG_INVALID(net, IPPROTO_UDP))
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nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
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"nf_ct_udp: bad UDP 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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#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
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#include <linux/netfilter/nfnetlink.h>
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#include <linux/netfilter/nfnetlink_cttimeout.h>
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static int udp_timeout_nlattr_to_obj(struct nlattr *tb[], void *data)
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{
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unsigned int *timeouts = data;
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/* set default timeouts for UDP. */
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timeouts[UDP_CT_UNREPLIED] = udp_timeouts[UDP_CT_UNREPLIED];
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timeouts[UDP_CT_REPLIED] = udp_timeouts[UDP_CT_REPLIED];
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if (tb[CTA_TIMEOUT_UDP_UNREPLIED]) {
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timeouts[UDP_CT_UNREPLIED] =
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ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDP_UNREPLIED])) * HZ;
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}
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if (tb[CTA_TIMEOUT_UDP_REPLIED]) {
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timeouts[UDP_CT_REPLIED] =
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ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDP_REPLIED])) * HZ;
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}
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return 0;
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}
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static int
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udp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
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{
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const unsigned int *timeouts = data;
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NLA_PUT_BE32(skb, CTA_TIMEOUT_UDP_UNREPLIED,
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htonl(timeouts[UDP_CT_UNREPLIED] / HZ));
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NLA_PUT_BE32(skb, CTA_TIMEOUT_UDP_REPLIED,
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htonl(timeouts[UDP_CT_REPLIED] / HZ));
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return 0;
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nla_put_failure:
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return -ENOSPC;
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}
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static const struct nla_policy
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udp_timeout_nla_policy[CTA_TIMEOUT_UDP_MAX+1] = {
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[CTA_TIMEOUT_UDP_UNREPLIED] = { .type = NLA_U32 },
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[CTA_TIMEOUT_UDP_REPLIED] = { .type = NLA_U32 },
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};
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#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
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#ifdef CONFIG_SYSCTL
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static unsigned int udp_sysctl_table_users;
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static struct ctl_table_header *udp_sysctl_header;
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static struct ctl_table udp_sysctl_table[] = {
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{
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.procname = "nf_conntrack_udp_timeout",
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.data = &udp_timeouts[UDP_CT_UNREPLIED],
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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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.procname = "nf_conntrack_udp_timeout_stream",
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.data = &udp_timeouts[UDP_CT_REPLIED],
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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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};
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#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
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static struct ctl_table udp_compat_sysctl_table[] = {
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{
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.procname = "ip_conntrack_udp_timeout",
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.data = &udp_timeouts[UDP_CT_UNREPLIED],
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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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.procname = "ip_conntrack_udp_timeout_stream",
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.data = &udp_timeouts[UDP_CT_REPLIED],
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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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};
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#endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
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#endif /* CONFIG_SYSCTL */
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struct nf_conntrack_l4proto nf_conntrack_l4proto_udp4 __read_mostly =
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{
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.l3proto = PF_INET,
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.l4proto = IPPROTO_UDP,
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.name = "udp",
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.pkt_to_tuple = udp_pkt_to_tuple,
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.invert_tuple = udp_invert_tuple,
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.print_tuple = udp_print_tuple,
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.packet = udp_packet,
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.get_timeouts = udp_get_timeouts,
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.new = udp_new,
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.error = udp_error,
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#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
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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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.nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
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.nla_policy = nf_ct_port_nla_policy,
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#endif
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#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
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.ctnl_timeout = {
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.nlattr_to_obj = udp_timeout_nlattr_to_obj,
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.obj_to_nlattr = udp_timeout_obj_to_nlattr,
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.nlattr_max = CTA_TIMEOUT_UDP_MAX,
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.obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX,
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.nla_policy = udp_timeout_nla_policy,
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},
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#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
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#ifdef CONFIG_SYSCTL
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.ctl_table_users = &udp_sysctl_table_users,
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.ctl_table_header = &udp_sysctl_header,
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.ctl_table = udp_sysctl_table,
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#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
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.ctl_compat_table = udp_compat_sysctl_table,
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#endif
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#endif
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};
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EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp4);
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struct nf_conntrack_l4proto nf_conntrack_l4proto_udp6 __read_mostly =
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{
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.l3proto = PF_INET6,
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.l4proto = IPPROTO_UDP,
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.name = "udp",
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.pkt_to_tuple = udp_pkt_to_tuple,
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.invert_tuple = udp_invert_tuple,
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.print_tuple = udp_print_tuple,
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.packet = udp_packet,
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.get_timeouts = udp_get_timeouts,
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.new = udp_new,
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.error = udp_error,
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#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
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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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.nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
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.nla_policy = nf_ct_port_nla_policy,
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#endif
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#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
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.ctnl_timeout = {
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.nlattr_to_obj = udp_timeout_nlattr_to_obj,
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.obj_to_nlattr = udp_timeout_obj_to_nlattr,
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.nlattr_max = CTA_TIMEOUT_UDP_MAX,
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.obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX,
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.nla_policy = udp_timeout_nla_policy,
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},
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#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
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#ifdef CONFIG_SYSCTL
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.ctl_table_users = &udp_sysctl_table_users,
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.ctl_table_header = &udp_sysctl_header,
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.ctl_table = udp_sysctl_table,
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#endif
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};
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EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp6);
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