2ae15b64e6
Updates the MODULE_DESCRIPTION() tags for all Netfilter modules, actually describing what the module does and not just "netfilter XYZ target". Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
366 lines
11 KiB
C
366 lines
11 KiB
C
/*
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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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* Copyright © CC Computer Consultants GmbH, 2007 - 2008
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* Jan Engelhardt <jengelh@computergmbh.de>
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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/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_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_mt_v0(const struct sk_buff *skb, const struct net_device *in,
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const struct net_device *out, const struct xt_match *match,
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const void *matchinfo, int offset, unsigned int protoff,
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bool *hotdrop)
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{
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const struct xt_conntrack_info *sinfo = matchinfo;
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const struct nf_conn *ct;
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enum ip_conntrack_info ctinfo;
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unsigned int statebit;
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ct = nf_ct_get(skb, &ctinfo);
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#define FWINV(bool, invflg) ((bool) ^ !!(sinfo->invflags & (invflg)))
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if (ct == &nf_conntrack_untracked)
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statebit = XT_CONNTRACK_STATE_UNTRACKED;
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else if (ct)
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statebit = XT_CONNTRACK_STATE_BIT(ctinfo);
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else
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statebit = XT_CONNTRACK_STATE_INVALID;
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if (sinfo->flags & XT_CONNTRACK_STATE) {
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if (ct) {
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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 (FWINV((statebit & sinfo->statemask) == 0,
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XT_CONNTRACK_STATE))
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return false;
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}
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if (ct == NULL) {
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if (sinfo->flags & ~XT_CONNTRACK_STATE)
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return false;
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return true;
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}
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if (sinfo->flags & XT_CONNTRACK_PROTO &&
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FWINV(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum !=
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sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.protonum,
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XT_CONNTRACK_PROTO))
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return false;
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if (sinfo->flags & XT_CONNTRACK_ORIGSRC &&
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FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip &
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sinfo->sipmsk[IP_CT_DIR_ORIGINAL].s_addr) !=
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sinfo->tuple[IP_CT_DIR_ORIGINAL].src.ip,
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XT_CONNTRACK_ORIGSRC))
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return false;
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if (sinfo->flags & XT_CONNTRACK_ORIGDST &&
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FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.ip &
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sinfo->dipmsk[IP_CT_DIR_ORIGINAL].s_addr) !=
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sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.ip,
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XT_CONNTRACK_ORIGDST))
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return false;
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if (sinfo->flags & XT_CONNTRACK_REPLSRC &&
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FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3.ip &
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sinfo->sipmsk[IP_CT_DIR_REPLY].s_addr) !=
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sinfo->tuple[IP_CT_DIR_REPLY].src.ip,
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XT_CONNTRACK_REPLSRC))
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return false;
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if (sinfo->flags & XT_CONNTRACK_REPLDST &&
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FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip &
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sinfo->dipmsk[IP_CT_DIR_REPLY].s_addr) !=
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sinfo->tuple[IP_CT_DIR_REPLY].dst.ip,
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XT_CONNTRACK_REPLDST))
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return false;
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if (sinfo->flags & XT_CONNTRACK_STATUS &&
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FWINV((ct->status & sinfo->statusmask) == 0,
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XT_CONNTRACK_STATUS))
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return false;
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if(sinfo->flags & XT_CONNTRACK_EXPIRES) {
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unsigned long expires = timer_pending(&ct->timeout) ?
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(ct->timeout.expires - jiffies)/HZ : 0;
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if (FWINV(!(expires >= sinfo->expires_min &&
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expires <= sinfo->expires_max),
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XT_CONNTRACK_EXPIRES))
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return false;
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}
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return true;
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#undef FWINV
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}
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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 == AF_INET)
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return (kaddr->ip & umask->ip) == uaddr->ip;
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else if (l3proto == AF_INET6)
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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_mtinfo1 *info,
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unsigned int 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_mtinfo1 *info,
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unsigned int 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_mtinfo1 *info,
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unsigned int 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_mtinfo1 *info,
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unsigned int 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 bool
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conntrack_mt(const struct sk_buff *skb, const struct net_device *in,
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const struct net_device *out, const struct xt_match *match,
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const void *matchinfo, int offset, unsigned int protoff,
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bool *hotdrop)
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{
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const struct xt_conntrack_mtinfo1 *info = 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 == &nf_conntrack_untracked)
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statebit = XT_CONNTRACK_STATE_UNTRACKED;
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else if (ct != NULL)
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statebit = XT_CONNTRACK_STATE_BIT(ctinfo);
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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 ((info->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_PROTO) &&
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((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum ==
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info->l4proto) ^ !(info->invert_flags & XT_CONNTRACK_PROTO)))
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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, match->family) ^
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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, match->family) ^
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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, match->family) ^
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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, match->family) ^
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!(info->invert_flags & XT_CONNTRACK_REPLDST))
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return false;
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if ((info->match_flags & XT_CONNTRACK_STATUS) &&
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(!!(info->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 = 0;
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if (timer_pending(&ct->timeout))
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expires = (ct->timeout.expires - jiffies) / 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_check(const char *tablename, const void *ip,
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const struct xt_match *match, void *matchinfo,
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unsigned int hook_mask)
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{
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if (nf_ct_l3proto_try_module_get(match->family) < 0) {
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printk(KERN_WARNING "can't load conntrack support for "
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"proto=%u\n", match->family);
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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 void
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conntrack_mt_destroy(const struct xt_match *match, void *matchinfo)
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{
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nf_ct_l3proto_module_put(match->family);
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}
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#ifdef CONFIG_COMPAT
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struct compat_xt_conntrack_info
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{
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compat_uint_t statemask;
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compat_uint_t statusmask;
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struct ip_conntrack_old_tuple tuple[IP_CT_DIR_MAX];
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struct in_addr sipmsk[IP_CT_DIR_MAX];
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struct in_addr dipmsk[IP_CT_DIR_MAX];
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compat_ulong_t expires_min;
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compat_ulong_t expires_max;
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u_int8_t flags;
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u_int8_t invflags;
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};
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static void conntrack_mt_compat_from_user_v0(void *dst, void *src)
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{
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const struct compat_xt_conntrack_info *cm = src;
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struct xt_conntrack_info m = {
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.statemask = cm->statemask,
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.statusmask = cm->statusmask,
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.expires_min = cm->expires_min,
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.expires_max = cm->expires_max,
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.flags = cm->flags,
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.invflags = cm->invflags,
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};
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memcpy(m.tuple, cm->tuple, sizeof(m.tuple));
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memcpy(m.sipmsk, cm->sipmsk, sizeof(m.sipmsk));
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memcpy(m.dipmsk, cm->dipmsk, sizeof(m.dipmsk));
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memcpy(dst, &m, sizeof(m));
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}
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static int conntrack_mt_compat_to_user_v0(void __user *dst, void *src)
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{
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const struct xt_conntrack_info *m = src;
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struct compat_xt_conntrack_info cm = {
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.statemask = m->statemask,
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.statusmask = m->statusmask,
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.expires_min = m->expires_min,
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.expires_max = m->expires_max,
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.flags = m->flags,
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.invflags = m->invflags,
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};
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memcpy(cm.tuple, m->tuple, sizeof(cm.tuple));
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memcpy(cm.sipmsk, m->sipmsk, sizeof(cm.sipmsk));
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memcpy(cm.dipmsk, m->dipmsk, sizeof(cm.dipmsk));
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return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
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}
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#endif
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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 = 0,
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.family = AF_INET,
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.match = conntrack_mt_v0,
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.checkentry = conntrack_mt_check,
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.destroy = conntrack_mt_destroy,
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.matchsize = sizeof(struct xt_conntrack_info),
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.me = THIS_MODULE,
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#ifdef CONFIG_COMPAT
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.compatsize = sizeof(struct compat_xt_conntrack_info),
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.compat_from_user = conntrack_mt_compat_from_user_v0,
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.compat_to_user = conntrack_mt_compat_to_user_v0,
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#endif
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},
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{
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.name = "conntrack",
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.revision = 1,
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.family = AF_INET,
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.matchsize = sizeof(struct xt_conntrack_mtinfo1),
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.match = conntrack_mt,
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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 = 1,
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.family = AF_INET6,
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.matchsize = sizeof(struct xt_conntrack_mtinfo1),
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.match = conntrack_mt,
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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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