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@@ -0,0 +1,292 @@
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+/*
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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, write to the Free Software
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+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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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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+
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+#define KMSG_COMPONENT "IPVS"
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+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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+
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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_helper.h>
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+#include <net/netfilter/nf_conntrack_zones.h>
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+
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+
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+#define FMT_TUPLE "%pI4:%u->%pI4:%u/%u"
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+#define ARG_TUPLE(T) &(T)->src.u3.ip, ntohs((T)->src.u.all), \
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+ &(T)->dst.u3.ip, ntohs((T)->dst.u.all), \
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+ (T)->dst.protonum
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+
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+#define FMT_CONN "%pI4:%u->%pI4:%u->%pI4:%u/%u:%u"
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+#define ARG_CONN(C) &((C)->caddr.ip), ntohs((C)->cport), \
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+ &((C)->vaddr.ip), ntohs((C)->vport), \
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+ &((C)->daddr.ip), ntohs((C)->dport), \
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+ (C)->protocol, (C)->state
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+
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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 = ct = nf_ct_get(skb, &ctinfo);
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+ struct nf_conntrack_tuple new_tuple;
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+
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+ if (ct == NULL || nf_ct_is_confirmed(ct) || nf_ct_is_untracked(ct) ||
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+ nf_ct_is_dying(ct))
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+ return;
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+
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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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+
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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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+
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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(7, "%s: Updating conntrack ct=%p, status=0x%lX, "
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+ "ctinfo=%d, old reply=" FMT_TUPLE
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+ ", new reply=" FMT_TUPLE ", cp=" FMT_CONN "\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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+ ARG_TUPLE(&new_tuple), ARG_CONN(cp));
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+ nf_conntrack_alter_reply(ct, &new_tuple);
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+}
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+
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+int ip_vs_confirm_conntrack(struct sk_buff *skb, struct ip_vs_conn *cp)
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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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+/*
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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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+
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+ if (exp->tuple.src.l3num != PF_INET)
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+ return;
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+
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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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+
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+ /* RS->CLIENT */
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+ orig = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
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+ cp = ip_vs_conn_out_get(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);
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+ if (cp) {
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+ /* Change reply CLIENT->RS to CLIENT->VS */
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+ new_reply = ct->tuplehash[IP_CT_DIR_REPLY].tuple;
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+ IP_VS_DBG(7, "%s: ct=%p, status=0x%lX, tuples=" FMT_TUPLE ", "
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+ FMT_TUPLE ", found inout cp=" FMT_CONN "\n",
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+ __func__, ct, ct->status,
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+ ARG_TUPLE(orig), ARG_TUPLE(&new_reply),
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+ ARG_CONN(cp));
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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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+ IP_VS_DBG(7, "%s: ct=%p, new tuples=" FMT_TUPLE ", " FMT_TUPLE
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+ ", inout cp=" FMT_CONN "\n",
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+ __func__, ct,
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+ ARG_TUPLE(orig), ARG_TUPLE(&new_reply),
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+ ARG_CONN(cp));
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+ goto alter;
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+ }
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+
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+ /* CLIENT->VS */
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+ cp = ip_vs_conn_in_get(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);
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+ if (cp) {
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+ /* Change reply VS->CLIENT to RS->CLIENT */
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+ new_reply = ct->tuplehash[IP_CT_DIR_REPLY].tuple;
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+ IP_VS_DBG(7, "%s: ct=%p, status=0x%lX, tuples=" FMT_TUPLE ", "
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+ FMT_TUPLE ", found outin cp=" FMT_CONN "\n",
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+ __func__, ct, ct->status,
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+ ARG_TUPLE(orig), ARG_TUPLE(&new_reply),
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+ ARG_CONN(cp));
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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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+ IP_VS_DBG(7, "%s: ct=%p, new tuples=" FMT_TUPLE ", "
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+ FMT_TUPLE ", outin cp=" FMT_CONN "\n",
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+ __func__, ct,
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+ ARG_TUPLE(orig), ARG_TUPLE(&new_reply),
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+ ARG_CONN(cp));
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+ goto alter;
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+ }
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+
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+ IP_VS_DBG(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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+
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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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+/*
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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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+
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+ if (ct == NULL || nf_ct_is_untracked(ct))
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+ return;
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+
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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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+
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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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+
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+ exp->expectfn = ip_vs_nfct_expect_callback;
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+
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+ IP_VS_DBG(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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+/*
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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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+
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+ if (!cp->cport)
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+ return;
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+
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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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+
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+ IP_VS_DBG(7, "%s: dropping conntrack with tuple=" FMT_TUPLE
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+ " for conn " FMT_CONN "\n",
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+ __func__, ARG_TUPLE(&tuple), ARG_CONN(cp));
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+
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+ h = nf_conntrack_find_get(&init_net, NF_CT_DEFAULT_ZONE, &tuple);
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+ if (h) {
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+ ct = nf_ct_tuplehash_to_ctrack(h);
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+ /* Show what happens instead of calling nf_ct_kill() */
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+ if (del_timer(&ct->timeout)) {
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+ IP_VS_DBG(7, "%s: ct=%p, deleted conntrack timer for tuple="
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+ FMT_TUPLE "\n",
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+ __func__, ct, ARG_TUPLE(&tuple));
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+ if (ct->timeout.function)
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+ ct->timeout.function(ct->timeout.data);
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+ } else {
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+ IP_VS_DBG(7, "%s: ct=%p, no conntrack timer 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(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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+
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Julian Anastasov