1 files changed, 292 insertions, 0 deletions
diff --git a/net/netfilter/ipvs/ip_vs_nfct.c b/net/netfilter/ipvs/ip_vs_nfct.c
new file mode 100644
index 000000000000..c038458d0290
--- /dev/null
+++ b/net/netfilter/ipvs/ip_vs_nfct.c
@@ -0,0 +1,292 @@
+/*
+ * ip_vs_nfct.c:	Netfilter connection tracking support for IPVS
+ *
+ * Portions Copyright (C) 2001-2002
+ * Antefacto Ltd, 181 Parnell St, Dublin 1, Ireland.
+ *
+ * Portions Copyright (C) 2003-2010
+ * Julian Anastasov
+ *
+ *
+ * This code is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *
+ * Authors:
+ * Ben North <ben@redfrontdoor.org>
+ * Julian Anastasov <ja@ssi.bg>		Reorganize and sync with latest kernels
+ * Hannes Eder <heder@google.com>	Extend NFCT support for FTP, ipvs match
+ *
+ *
+ * Current status:
+ *
+ * - provide conntrack confirmation for new and related connections, by
+ * this way we can see their proper conntrack state in all hooks
+ * - support for all forwarding methods, not only NAT
+ * - FTP support (NAT), ability to support other NAT apps with expectations
+ * - to correctly create expectations for related NAT connections the proper
+ * NF conntrack support must be already installed, eg. ip_vs_ftp requires
+ * nf_conntrack_ftp ... iptables_nat for the same ports (but no iptables
+ * NAT rules are needed)
+ * - alter reply for NAT when forwarding packet in original direction:
+ * conntrack from client in NEW or RELATED (Passive FTP DATA) state or
+ * when RELATED conntrack is created from real server (Active FTP DATA)
+ * - if iptables_nat is not loaded the Passive FTP will not work (the
+ * PASV response can not be NAT-ed) but Active FTP should work
+ *
+ */
+
+#define KMSG_COMPONENT "IPVS"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/compiler.h>
+#include <linux/vmalloc.h>
+#include <linux/skbuff.h>
+#include <net/ip.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv4.h>
+#include <net/ip_vs.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_conntrack_expect.h>
+#include <net/netfilter/nf_conntrack_helper.h>
+#include <net/netfilter/nf_conntrack_zones.h>
+
+
+#define FMT_TUPLE	"%pI4:%u->%pI4:%u/%u"
+#define ARG_TUPLE(T)	&(T)->src.u3.ip, ntohs((T)->src.u.all), \
+			&(T)->dst.u3.ip, ntohs((T)->dst.u.all), \
+			(T)->dst.protonum
+
+#define FMT_CONN	"%pI4:%u->%pI4:%u->%pI4:%u/%u:%u"
+#define ARG_CONN(C)	&((C)->caddr.ip), ntohs((C)->cport), \
+			&((C)->vaddr.ip), ntohs((C)->vport), \
+			&((C)->daddr.ip), ntohs((C)->dport), \
+			(C)->protocol, (C)->state
+
+void
+ip_vs_update_conntrack(struct sk_buff *skb, struct ip_vs_conn *cp, int outin)
+{
+	enum ip_conntrack_info ctinfo;
+	struct nf_conn *ct = ct = nf_ct_get(skb, &ctinfo);
+	struct nf_conntrack_tuple new_tuple;
+
+	if (ct == NULL || nf_ct_is_confirmed(ct) || nf_ct_is_untracked(ct) ||
+	    nf_ct_is_dying(ct))
+		return;
+
+	/* Never alter conntrack for non-NAT conns */
+	if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ)
+		return;
+
+	/* Alter reply only in original direction */
+	if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
+		return;
+
+	/*
+	 * The connection is not yet in the hashtable, so we update it.
+	 * CIP->VIP will remain the same, so leave the tuple in
+	 * IP_CT_DIR_ORIGINAL untouched.  When the reply comes back from the
+	 * real-server we will see RIP->DIP.
+	 */
+	new_tuple = ct->tuplehash[IP_CT_DIR_REPLY].tuple;
+	/*
+	 * This will also take care of UDP and other protocols.
+	 */
+	if (outin) {
+		new_tuple.src.u3 = cp->daddr;
+		if (new_tuple.dst.protonum != IPPROTO_ICMP &&
+		    new_tuple.dst.protonum != IPPROTO_ICMPV6)
+			new_tuple.src.u.tcp.port = cp->dport;
+	} else {
+		new_tuple.dst.u3 = cp->vaddr;
+		if (new_tuple.dst.protonum != IPPROTO_ICMP &&
+		    new_tuple.dst.protonum != IPPROTO_ICMPV6)
+			new_tuple.dst.u.tcp.port = cp->vport;
+	}
+	IP_VS_DBG(7, "%s: Updating conntrack ct=%p, status=0x%lX, "
+		  "ctinfo=%d, old reply=" FMT_TUPLE
+		  ", new reply=" FMT_TUPLE ", cp=" FMT_CONN "\n",
+		  __func__, ct, ct->status, ctinfo,
+		  ARG_TUPLE(&ct->tuplehash[IP_CT_DIR_REPLY].tuple),
+		  ARG_TUPLE(&new_tuple), ARG_CONN(cp));
+	nf_conntrack_alter_reply(ct, &new_tuple);
+}
+
+int ip_vs_confirm_conntrack(struct sk_buff *skb, struct ip_vs_conn *cp)
+{
+	return nf_conntrack_confirm(skb);
+}
+
+/*
+ * Called from init_conntrack() as expectfn handler.
+ */
+static void ip_vs_nfct_expect_callback(struct nf_conn *ct,
+	struct nf_conntrack_expect *exp)
+{
+	struct nf_conntrack_tuple *orig, new_reply;
+	struct ip_vs_conn *cp;
+
+	if (exp->tuple.src.l3num != PF_INET)
+		return;
+
+	/*
+	 * We assume that no NF locks are held before this callback.
+	 * ip_vs_conn_out_get and ip_vs_conn_in_get should match their
+	 * expectations even if they use wildcard values, now we provide the
+	 * actual values from the newly created original conntrack direction.
+	 * The conntrack is confirmed when packet reaches IPVS hooks.
+	 */
+
+	/* RS->CLIENT */
+	orig = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
+	cp = ip_vs_conn_out_get(exp->tuple.src.l3num, orig->dst.protonum,
+				&orig->src.u3, orig->src.u.tcp.port,
+				&orig->dst.u3, orig->dst.u.tcp.port);
+	if (cp) {
+		/* Change reply CLIENT->RS to CLIENT->VS */
+		new_reply = ct->tuplehash[IP_CT_DIR_REPLY].tuple;
+		IP_VS_DBG(7, "%s: ct=%p, status=0x%lX, tuples=" FMT_TUPLE ", "
+			  FMT_TUPLE ", found inout cp=" FMT_CONN "\n",
+			  __func__, ct, ct->status,
+			  ARG_TUPLE(orig), ARG_TUPLE(&new_reply),
+			  ARG_CONN(cp));
+		new_reply.dst.u3 = cp->vaddr;
+		new_reply.dst.u.tcp.port = cp->vport;
+		IP_VS_DBG(7, "%s: ct=%p, new tuples=" FMT_TUPLE ", " FMT_TUPLE
+			  ", inout cp=" FMT_CONN "\n",
+			  __func__, ct,
+			  ARG_TUPLE(orig), ARG_TUPLE(&new_reply),
+			  ARG_CONN(cp));
+		goto alter;
+	}
+
+	/* CLIENT->VS */
+	cp = ip_vs_conn_in_get(exp->tuple.src.l3num, orig->dst.protonum,
+			       &orig->src.u3, orig->src.u.tcp.port,
+			       &orig->dst.u3, orig->dst.u.tcp.port);
+	if (cp) {
+		/* Change reply VS->CLIENT to RS->CLIENT */
+		new_reply = ct->tuplehash[IP_CT_DIR_REPLY].tuple;
+		IP_VS_DBG(7, "%s: ct=%p, status=0x%lX, tuples=" FMT_TUPLE ", "
+			  FMT_TUPLE ", found outin cp=" FMT_CONN "\n",
+			  __func__, ct, ct->status,
+			  ARG_TUPLE(orig), ARG_TUPLE(&new_reply),
+			  ARG_CONN(cp));
+		new_reply.src.u3 = cp->daddr;
+		new_reply.src.u.tcp.port = cp->dport;
+		IP_VS_DBG(7, "%s: ct=%p, new tuples=" FMT_TUPLE ", "
+			  FMT_TUPLE ", outin cp=" FMT_CONN "\n",
+			  __func__, ct,
+			  ARG_TUPLE(orig), ARG_TUPLE(&new_reply),
+			  ARG_CONN(cp));
+		goto alter;
+	}
+
+	IP_VS_DBG(7, "%s: ct=%p, status=0x%lX, tuple=" FMT_TUPLE
+		  " - unknown expect\n",
+		  __func__, ct, ct->status, ARG_TUPLE(orig));
+	return;
+
+alter:
+	/* Never alter conntrack for non-NAT conns */
+	if (IP_VS_FWD_METHOD(cp) == IP_VS_CONN_F_MASQ)
+		nf_conntrack_alter_reply(ct, &new_reply);
+	ip_vs_conn_put(cp);
+	return;
+}
+
+/*
+ * Create NF conntrack expectation with wildcard (optional) source port.
+ * Then the default callback function will alter the reply and will confirm
+ * the conntrack entry when the first packet comes.
+ * Use port 0 to expect connection from any port.
+ */
+void ip_vs_nfct_expect_related(struct sk_buff *skb, struct nf_conn *ct,
+			       struct ip_vs_conn *cp, u_int8_t proto,
+			       const __be16 port, int from_rs)
+{
+	struct nf_conntrack_expect *exp;
+
+	if (ct == NULL || nf_ct_is_untracked(ct))
+		return;
+
+	exp = nf_ct_expect_alloc(ct);
+	if (!exp)
+		return;
+
+	nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct),
+			from_rs ? &cp->daddr : &cp->caddr,
+			from_rs ? &cp->caddr : &cp->vaddr,
+			proto, port ? &port : NULL,
+			from_rs ? &cp->cport : &cp->vport);
+
+	exp->expectfn = ip_vs_nfct_expect_callback;
+
+	IP_VS_DBG(7, "%s: ct=%p, expect tuple=" FMT_TUPLE "\n",
+		__func__, ct, ARG_TUPLE(&exp->tuple));
+	nf_ct_expect_related(exp);
+	nf_ct_expect_put(exp);
+}
+EXPORT_SYMBOL(ip_vs_nfct_expect_related);
+
+/*
+ * Our connection was terminated, try to drop the conntrack immediately
+ */
+void ip_vs_conn_drop_conntrack(struct ip_vs_conn *cp)
+{
+	struct nf_conntrack_tuple_hash *h;
+	struct nf_conn *ct;
+	struct nf_conntrack_tuple tuple;
+
+	if (!cp->cport)
+		return;
+
+	tuple = (struct nf_conntrack_tuple) {
+		.dst = { .protonum = cp->protocol, .dir = IP_CT_DIR_ORIGINAL } };
+	tuple.src.u3 = cp->caddr;
+	tuple.src.u.all = cp->cport;
+	tuple.src.l3num = cp->af;
+	tuple.dst.u3 = cp->vaddr;
+	tuple.dst.u.all = cp->vport;
+
+	IP_VS_DBG(7, "%s: dropping conntrack with tuple=" FMT_TUPLE
+		" for conn " FMT_CONN "\n",
+		__func__, ARG_TUPLE(&tuple), ARG_CONN(cp));
+
+	h = nf_conntrack_find_get(&init_net, NF_CT_DEFAULT_ZONE, &tuple);
+	if (h) {
+		ct = nf_ct_tuplehash_to_ctrack(h);
+		/* Show what happens instead of calling nf_ct_kill() */
+		if (del_timer(&ct->timeout)) {
+			IP_VS_DBG(7, "%s: ct=%p, deleted conntrack timer for tuple="
+				FMT_TUPLE "\n",
+				__func__, ct, ARG_TUPLE(&tuple));
+			if (ct->timeout.function)
+				ct->timeout.function(ct->timeout.data);
+		} else {
+			IP_VS_DBG(7, "%s: ct=%p, no conntrack timer for tuple="
+				FMT_TUPLE "\n",
+				__func__, ct, ARG_TUPLE(&tuple));
+		}
+		nf_ct_put(ct);
+	} else {
+		IP_VS_DBG(7, "%s: no conntrack for tuple=" FMT_TUPLE "\n",
+			__func__, ARG_TUPLE(&tuple));
+	}
+}
+