/*
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* ip_vs_nfct.c: Netfilter connection tracking support for IPVS
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*
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* Portions Copyright (C) 2001-2002
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* Antefacto Ltd, 181 Parnell St, Dublin 1, Ireland.
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*
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* Portions Copyright (C) 2003-2010
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* Julian Anastasov
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*
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*
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* This code is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*
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*
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* Authors:
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* Ben North <ben@redfrontdoor.org>
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* Julian Anastasov <ja@ssi.bg> Reorganize and sync with latest kernels
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* Hannes Eder <heder@google.com> Extend NFCT support for FTP, ipvs match
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*
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*
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* Current status:
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*
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* - provide conntrack confirmation for new and related connections, by
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* this way we can see their proper conntrack state in all hooks
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* - support for all forwarding methods, not only NAT
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* - FTP support (NAT), ability to support other NAT apps with expectations
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* - to correctly create expectations for related NAT connections the proper
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* NF conntrack support must be already installed, eg. ip_vs_ftp requires
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* nf_conntrack_ftp ... iptables_nat for the same ports (but no iptables
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* NAT rules are needed)
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* - alter reply for NAT when forwarding packet in original direction:
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* conntrack from client in NEW or RELATED (Passive FTP DATA) state or
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* when RELATED conntrack is created from real server (Active FTP DATA)
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* - if iptables_nat is not loaded the Passive FTP will not work (the
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* PASV response can not be NAT-ed) but Active FTP should work
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*
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*/
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#define KMSG_COMPONENT "IPVS"
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/compiler.h>
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#include <linux/vmalloc.h>
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#include <linux/skbuff.h>
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#include <net/ip.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter_ipv4.h>
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#include <net/ip_vs.h>
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#include <net/netfilter/nf_conntrack_core.h>
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#include <net/netfilter/nf_conntrack_expect.h>
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#include <net/netfilter/nf_conntrack_seqadj.h>
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#include <net/netfilter/nf_conntrack_helper.h>
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#include <net/netfilter/nf_conntrack_zones.h>
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#define FMT_TUPLE "%s:%u->%s:%u/%u"
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#define ARG_TUPLE(T) IP_VS_DBG_ADDR((T)->src.l3num, &(T)->src.u3), \
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ntohs((T)->src.u.all), \
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IP_VS_DBG_ADDR((T)->src.l3num, &(T)->dst.u3), \
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ntohs((T)->dst.u.all), \
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(T)->dst.protonum
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#define FMT_CONN "%s:%u->%s:%u->%s:%u/%u:%u"
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#define ARG_CONN(C) IP_VS_DBG_ADDR((C)->af, &((C)->caddr)), \
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ntohs((C)->cport), \
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IP_VS_DBG_ADDR((C)->af, &((C)->vaddr)), \
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ntohs((C)->vport), \
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IP_VS_DBG_ADDR((C)->daf, &((C)->daddr)), \
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ntohs((C)->dport), \
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(C)->protocol, (C)->state
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void
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ip_vs_update_conntrack(struct sk_buff *skb, struct ip_vs_conn *cp, int outin)
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{
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enum ip_conntrack_info ctinfo;
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struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
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struct nf_conntrack_tuple new_tuple;
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if (ct == NULL || nf_ct_is_confirmed(ct) ||
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nf_ct_is_dying(ct))
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return;
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/* Never alter conntrack for non-NAT conns */
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if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ)
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return;
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/* Never alter conntrack for OPS conns (no reply is expected) */
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if (cp->flags & IP_VS_CONN_F_ONE_PACKET)
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return;
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/* Alter reply only in original direction */
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if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
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return;
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/* Applications may adjust TCP seqs */
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if (cp->app && nf_ct_protonum(ct) == IPPROTO_TCP &&
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!nfct_seqadj(ct) && !nfct_seqadj_ext_add(ct))
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return;
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/*
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* The connection is not yet in the hashtable, so we update it.
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* CIP->VIP will remain the same, so leave the tuple in
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* IP_CT_DIR_ORIGINAL untouched. When the reply comes back from the
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* real-server we will see RIP->DIP.
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*/
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new_tuple = ct->tuplehash[IP_CT_DIR_REPLY].tuple;
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/*
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* This will also take care of UDP and other protocols.
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*/
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if (outin) {
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new_tuple.src.u3 = cp->daddr;
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if (new_tuple.dst.protonum != IPPROTO_ICMP &&
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new_tuple.dst.protonum != IPPROTO_ICMPV6)
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new_tuple.src.u.tcp.port = cp->dport;
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} else {
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new_tuple.dst.u3 = cp->vaddr;
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if (new_tuple.dst.protonum != IPPROTO_ICMP &&
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new_tuple.dst.protonum != IPPROTO_ICMPV6)
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new_tuple.dst.u.tcp.port = cp->vport;
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}
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IP_VS_DBG_BUF(7, "%s: Updating conntrack ct=%p, status=0x%lX, "
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"ctinfo=%d, old reply=" FMT_TUPLE "\n",
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__func__, ct, ct->status, ctinfo,
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ARG_TUPLE(&ct->tuplehash[IP_CT_DIR_REPLY].tuple));
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IP_VS_DBG_BUF(7, "%s: Updating conntrack ct=%p, status=0x%lX, "
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"ctinfo=%d, new reply=" FMT_TUPLE "\n",
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__func__, ct, ct->status, ctinfo,
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ARG_TUPLE(&new_tuple));
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nf_conntrack_alter_reply(ct, &new_tuple);
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IP_VS_DBG_BUF(7, "%s: Updated conntrack ct=%p for cp=" FMT_CONN "\n",
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__func__, ct, ARG_CONN(cp));
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}
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int ip_vs_confirm_conntrack(struct sk_buff *skb)
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{
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return nf_conntrack_confirm(skb);
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}
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/*
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* Called from init_conntrack() as expectfn handler.
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*/
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static void ip_vs_nfct_expect_callback(struct nf_conn *ct,
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struct nf_conntrack_expect *exp)
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{
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struct nf_conntrack_tuple *orig, new_reply;
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struct ip_vs_conn *cp;
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struct ip_vs_conn_param p;
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struct net *net = nf_ct_net(ct);
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/*
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* We assume that no NF locks are held before this callback.
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* ip_vs_conn_out_get and ip_vs_conn_in_get should match their
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* expectations even if they use wildcard values, now we provide the
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* actual values from the newly created original conntrack direction.
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* The conntrack is confirmed when packet reaches IPVS hooks.
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*/
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/* RS->CLIENT */
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orig = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
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ip_vs_conn_fill_param(net_ipvs(net), exp->tuple.src.l3num, orig->dst.protonum,
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&orig->src.u3, orig->src.u.tcp.port,
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&orig->dst.u3, orig->dst.u.tcp.port, &p);
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cp = ip_vs_conn_out_get(&p);
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if (cp) {
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/* Change reply CLIENT->RS to CLIENT->VS */
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IP_VS_DBG_BUF(7, "%s: for ct=%p, status=0x%lX found inout cp="
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FMT_CONN "\n",
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__func__, ct, ct->status, ARG_CONN(cp));
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new_reply = ct->tuplehash[IP_CT_DIR_REPLY].tuple;
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IP_VS_DBG_BUF(7, "%s: ct=%p before alter: reply tuple="
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FMT_TUPLE "\n",
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__func__, ct, ARG_TUPLE(&new_reply));
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new_reply.dst.u3 = cp->vaddr;
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new_reply.dst.u.tcp.port = cp->vport;
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goto alter;
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}
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/* CLIENT->VS */
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cp = ip_vs_conn_in_get(&p);
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if (cp) {
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/* Change reply VS->CLIENT to RS->CLIENT */
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IP_VS_DBG_BUF(7, "%s: for ct=%p, status=0x%lX found outin cp="
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FMT_CONN "\n",
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__func__, ct, ct->status, ARG_CONN(cp));
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new_reply = ct->tuplehash[IP_CT_DIR_REPLY].tuple;
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IP_VS_DBG_BUF(7, "%s: ct=%p before alter: reply tuple="
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FMT_TUPLE "\n",
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__func__, ct, ARG_TUPLE(&new_reply));
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new_reply.src.u3 = cp->daddr;
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new_reply.src.u.tcp.port = cp->dport;
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goto alter;
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}
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IP_VS_DBG_BUF(7, "%s: ct=%p, status=0x%lX, tuple=" FMT_TUPLE
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" - unknown expect\n",
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__func__, ct, ct->status, ARG_TUPLE(orig));
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return;
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alter:
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/* Never alter conntrack for non-NAT conns */
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if (IP_VS_FWD_METHOD(cp) == IP_VS_CONN_F_MASQ)
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nf_conntrack_alter_reply(ct, &new_reply);
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ip_vs_conn_put(cp);
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return;
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}
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/*
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* Create NF conntrack expectation with wildcard (optional) source port.
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* Then the default callback function will alter the reply and will confirm
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* the conntrack entry when the first packet comes.
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* Use port 0 to expect connection from any port.
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*/
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void ip_vs_nfct_expect_related(struct sk_buff *skb, struct nf_conn *ct,
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struct ip_vs_conn *cp, u_int8_t proto,
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const __be16 port, int from_rs)
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{
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struct nf_conntrack_expect *exp;
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if (ct == NULL)
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return;
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exp = nf_ct_expect_alloc(ct);
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if (!exp)
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return;
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nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct),
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from_rs ? &cp->daddr : &cp->caddr,
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from_rs ? &cp->caddr : &cp->vaddr,
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proto, port ? &port : NULL,
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from_rs ? &cp->cport : &cp->vport);
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exp->expectfn = ip_vs_nfct_expect_callback;
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IP_VS_DBG_BUF(7, "%s: ct=%p, expect tuple=" FMT_TUPLE "\n",
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__func__, ct, ARG_TUPLE(&exp->tuple));
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nf_ct_expect_related(exp);
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nf_ct_expect_put(exp);
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}
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EXPORT_SYMBOL(ip_vs_nfct_expect_related);
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/*
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* Our connection was terminated, try to drop the conntrack immediately
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*/
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void ip_vs_conn_drop_conntrack(struct ip_vs_conn *cp)
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{
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struct nf_conntrack_tuple_hash *h;
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struct nf_conn *ct;
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struct nf_conntrack_tuple tuple;
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if (!cp->cport)
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return;
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tuple = (struct nf_conntrack_tuple) {
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.dst = { .protonum = cp->protocol, .dir = IP_CT_DIR_ORIGINAL } };
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tuple.src.u3 = cp->caddr;
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tuple.src.u.all = cp->cport;
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tuple.src.l3num = cp->af;
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tuple.dst.u3 = cp->vaddr;
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tuple.dst.u.all = cp->vport;
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IP_VS_DBG_BUF(7, "%s: dropping conntrack for conn " FMT_CONN "\n",
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__func__, ARG_CONN(cp));
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h = nf_conntrack_find_get(cp->ipvs->net, &nf_ct_zone_dflt, &tuple);
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if (h) {
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ct = nf_ct_tuplehash_to_ctrack(h);
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if (nf_ct_kill(ct)) {
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IP_VS_DBG_BUF(7, "%s: ct=%p deleted for tuple="
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FMT_TUPLE "\n",
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__func__, ct, ARG_TUPLE(&tuple));
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} else {
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IP_VS_DBG_BUF(7, "%s: ct=%p, no conntrack for tuple="
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FMT_TUPLE "\n",
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__func__, ct, ARG_TUPLE(&tuple));
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}
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nf_ct_put(ct);
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} else {
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IP_VS_DBG_BUF(7, "%s: no conntrack for tuple=" FMT_TUPLE "\n",
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__func__, ARG_TUPLE(&tuple));
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}
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}
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