// SPDX-License-Identifier: GPL-2.0-only
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/*
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* xt_conntrack - Netfilter module to match connection tracking
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* information. (Superset of Rusty's minimalistic state match.)
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*
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* (C) 2001 Marc Boucher (marc@mbsi.ca).
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* (C) 2006-2012 Patrick McHardy <kaber@trash.net>
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* Copyright © CC Computer Consultants GmbH, 2007 - 2008
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <net/ipv6.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter/xt_conntrack.h>
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#include <net/netfilter/nf_conntrack.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
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MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
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MODULE_DESCRIPTION("Xtables: connection tracking state match");
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MODULE_ALIAS("ipt_conntrack");
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MODULE_ALIAS("ip6t_conntrack");
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static bool
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conntrack_addrcmp(const union nf_inet_addr *kaddr,
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const union nf_inet_addr *uaddr,
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const union nf_inet_addr *umask, unsigned int l3proto)
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{
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if (l3proto == NFPROTO_IPV4)
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return ((kaddr->ip ^ uaddr->ip) & umask->ip) == 0;
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else if (l3proto == NFPROTO_IPV6)
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return ipv6_masked_addr_cmp(&kaddr->in6, &umask->in6,
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&uaddr->in6) == 0;
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else
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return false;
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}
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static inline bool
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conntrack_mt_origsrc(const struct nf_conn *ct,
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const struct xt_conntrack_mtinfo2 *info,
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u_int8_t family)
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{
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return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3,
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&info->origsrc_addr, &info->origsrc_mask, family);
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}
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static inline bool
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conntrack_mt_origdst(const struct nf_conn *ct,
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const struct xt_conntrack_mtinfo2 *info,
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u_int8_t family)
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{
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return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3,
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&info->origdst_addr, &info->origdst_mask, family);
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}
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static inline bool
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conntrack_mt_replsrc(const struct nf_conn *ct,
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const struct xt_conntrack_mtinfo2 *info,
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u_int8_t family)
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{
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return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3,
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&info->replsrc_addr, &info->replsrc_mask, family);
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}
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static inline bool
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conntrack_mt_repldst(const struct nf_conn *ct,
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const struct xt_conntrack_mtinfo2 *info,
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u_int8_t family)
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{
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return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3,
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&info->repldst_addr, &info->repldst_mask, family);
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}
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static inline bool
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ct_proto_port_check(const struct xt_conntrack_mtinfo2 *info,
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const struct nf_conn *ct)
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{
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const struct nf_conntrack_tuple *tuple;
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tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
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if ((info->match_flags & XT_CONNTRACK_PROTO) &&
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(nf_ct_protonum(ct) == info->l4proto) ^
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!(info->invert_flags & XT_CONNTRACK_PROTO))
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return false;
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/* Shortcut to match all recognized protocols by using ->src.all. */
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if ((info->match_flags & XT_CONNTRACK_ORIGSRC_PORT) &&
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(tuple->src.u.all == info->origsrc_port) ^
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!(info->invert_flags & XT_CONNTRACK_ORIGSRC_PORT))
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return false;
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if ((info->match_flags & XT_CONNTRACK_ORIGDST_PORT) &&
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(tuple->dst.u.all == info->origdst_port) ^
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!(info->invert_flags & XT_CONNTRACK_ORIGDST_PORT))
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return false;
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tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
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if ((info->match_flags & XT_CONNTRACK_REPLSRC_PORT) &&
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(tuple->src.u.all == info->replsrc_port) ^
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!(info->invert_flags & XT_CONNTRACK_REPLSRC_PORT))
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return false;
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if ((info->match_flags & XT_CONNTRACK_REPLDST_PORT) &&
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(tuple->dst.u.all == info->repldst_port) ^
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!(info->invert_flags & XT_CONNTRACK_REPLDST_PORT))
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return false;
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return true;
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}
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static inline bool
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port_match(u16 min, u16 max, u16 port, bool invert)
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{
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return (port >= min && port <= max) ^ invert;
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}
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static inline bool
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ct_proto_port_check_v3(const struct xt_conntrack_mtinfo3 *info,
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const struct nf_conn *ct)
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{
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const struct nf_conntrack_tuple *tuple;
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tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
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if ((info->match_flags & XT_CONNTRACK_PROTO) &&
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(nf_ct_protonum(ct) == info->l4proto) ^
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!(info->invert_flags & XT_CONNTRACK_PROTO))
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return false;
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/* Shortcut to match all recognized protocols by using ->src.all. */
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if ((info->match_flags & XT_CONNTRACK_ORIGSRC_PORT) &&
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!port_match(info->origsrc_port, info->origsrc_port_high,
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ntohs(tuple->src.u.all),
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info->invert_flags & XT_CONNTRACK_ORIGSRC_PORT))
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return false;
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if ((info->match_flags & XT_CONNTRACK_ORIGDST_PORT) &&
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!port_match(info->origdst_port, info->origdst_port_high,
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ntohs(tuple->dst.u.all),
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info->invert_flags & XT_CONNTRACK_ORIGDST_PORT))
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return false;
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tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
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if ((info->match_flags & XT_CONNTRACK_REPLSRC_PORT) &&
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!port_match(info->replsrc_port, info->replsrc_port_high,
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ntohs(tuple->src.u.all),
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info->invert_flags & XT_CONNTRACK_REPLSRC_PORT))
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return false;
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if ((info->match_flags & XT_CONNTRACK_REPLDST_PORT) &&
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!port_match(info->repldst_port, info->repldst_port_high,
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ntohs(tuple->dst.u.all),
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info->invert_flags & XT_CONNTRACK_REPLDST_PORT))
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return false;
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return true;
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}
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static bool
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conntrack_mt(const struct sk_buff *skb, struct xt_action_param *par,
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u16 state_mask, u16 status_mask)
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{
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const struct xt_conntrack_mtinfo2 *info = par->matchinfo;
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enum ip_conntrack_info ctinfo;
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const struct nf_conn *ct;
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unsigned int statebit;
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ct = nf_ct_get(skb, &ctinfo);
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if (ct)
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statebit = XT_CONNTRACK_STATE_BIT(ctinfo);
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else if (ctinfo == IP_CT_UNTRACKED)
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statebit = XT_CONNTRACK_STATE_UNTRACKED;
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else
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statebit = XT_CONNTRACK_STATE_INVALID;
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if (info->match_flags & XT_CONNTRACK_STATE) {
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if (ct != NULL) {
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if (test_bit(IPS_SRC_NAT_BIT, &ct->status))
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statebit |= XT_CONNTRACK_STATE_SNAT;
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if (test_bit(IPS_DST_NAT_BIT, &ct->status))
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statebit |= XT_CONNTRACK_STATE_DNAT;
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}
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if (!!(state_mask & statebit) ^
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!(info->invert_flags & XT_CONNTRACK_STATE))
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return false;
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}
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if (ct == NULL)
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return info->match_flags & XT_CONNTRACK_STATE;
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if ((info->match_flags & XT_CONNTRACK_DIRECTION) &&
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(CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) ^
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!(info->invert_flags & XT_CONNTRACK_DIRECTION))
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return false;
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if (info->match_flags & XT_CONNTRACK_ORIGSRC)
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if (conntrack_mt_origsrc(ct, info, xt_family(par)) ^
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!(info->invert_flags & XT_CONNTRACK_ORIGSRC))
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return false;
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if (info->match_flags & XT_CONNTRACK_ORIGDST)
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if (conntrack_mt_origdst(ct, info, xt_family(par)) ^
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!(info->invert_flags & XT_CONNTRACK_ORIGDST))
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return false;
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if (info->match_flags & XT_CONNTRACK_REPLSRC)
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if (conntrack_mt_replsrc(ct, info, xt_family(par)) ^
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!(info->invert_flags & XT_CONNTRACK_REPLSRC))
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return false;
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if (info->match_flags & XT_CONNTRACK_REPLDST)
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if (conntrack_mt_repldst(ct, info, xt_family(par)) ^
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!(info->invert_flags & XT_CONNTRACK_REPLDST))
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return false;
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if (par->match->revision != 3) {
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if (!ct_proto_port_check(info, ct))
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return false;
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} else {
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if (!ct_proto_port_check_v3(par->matchinfo, ct))
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return false;
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}
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if ((info->match_flags & XT_CONNTRACK_STATUS) &&
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(!!(status_mask & ct->status) ^
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!(info->invert_flags & XT_CONNTRACK_STATUS)))
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return false;
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if (info->match_flags & XT_CONNTRACK_EXPIRES) {
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unsigned long expires = nf_ct_expires(ct) / HZ;
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if ((expires >= info->expires_min &&
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expires <= info->expires_max) ^
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!(info->invert_flags & XT_CONNTRACK_EXPIRES))
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return false;
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}
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return true;
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}
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static bool
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conntrack_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
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{
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const struct xt_conntrack_mtinfo1 *info = par->matchinfo;
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return conntrack_mt(skb, par, info->state_mask, info->status_mask);
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}
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static bool
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conntrack_mt_v2(const struct sk_buff *skb, struct xt_action_param *par)
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{
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const struct xt_conntrack_mtinfo2 *info = par->matchinfo;
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return conntrack_mt(skb, par, info->state_mask, info->status_mask);
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}
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static bool
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conntrack_mt_v3(const struct sk_buff *skb, struct xt_action_param *par)
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{
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const struct xt_conntrack_mtinfo3 *info = par->matchinfo;
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return conntrack_mt(skb, par, info->state_mask, info->status_mask);
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}
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static int conntrack_mt_check(const struct xt_mtchk_param *par)
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{
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int ret;
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ret = nf_ct_netns_get(par->net, par->family);
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if (ret < 0)
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pr_info_ratelimited("cannot load conntrack support for proto=%u\n",
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par->family);
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return ret;
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}
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static void conntrack_mt_destroy(const struct xt_mtdtor_param *par)
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{
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nf_ct_netns_put(par->net, par->family);
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}
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static struct xt_match conntrack_mt_reg[] __read_mostly = {
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{
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.name = "conntrack",
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.revision = 1,
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.family = NFPROTO_UNSPEC,
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.matchsize = sizeof(struct xt_conntrack_mtinfo1),
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.match = conntrack_mt_v1,
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.checkentry = conntrack_mt_check,
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.destroy = conntrack_mt_destroy,
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.me = THIS_MODULE,
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},
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{
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.name = "conntrack",
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.revision = 2,
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.family = NFPROTO_UNSPEC,
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.matchsize = sizeof(struct xt_conntrack_mtinfo2),
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.match = conntrack_mt_v2,
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.checkentry = conntrack_mt_check,
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.destroy = conntrack_mt_destroy,
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.me = THIS_MODULE,
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},
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{
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.name = "conntrack",
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.revision = 3,
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.family = NFPROTO_UNSPEC,
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.matchsize = sizeof(struct xt_conntrack_mtinfo3),
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.match = conntrack_mt_v3,
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.checkentry = conntrack_mt_check,
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.destroy = conntrack_mt_destroy,
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.me = THIS_MODULE,
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},
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};
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static int __init conntrack_mt_init(void)
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{
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return xt_register_matches(conntrack_mt_reg,
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ARRAY_SIZE(conntrack_mt_reg));
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}
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static void __exit conntrack_mt_exit(void)
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{
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xt_unregister_matches(conntrack_mt_reg, ARRAY_SIZE(conntrack_mt_reg));
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}
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module_init(conntrack_mt_init);
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module_exit(conntrack_mt_exit);
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