--- /dev/null
+/*
+ * 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, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * 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_seqadj.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 = 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;
+
+ /* Applications may adjust TCP seqs */
+ if (cp->app && nf_ct_protonum(ct) == IPPROTO_TCP &&
+ !nfct_seqadj(ct) && !nfct_seqadj_ext_add(ct))
+ 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)
+{
+ 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;
+ struct ip_vs_conn_param p;
+ struct net *net = nf_ct_net(ct);
+
+ 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;
+ ip_vs_conn_fill_param(net, exp->tuple.src.l3num, orig->dst.protonum,
+ &orig->src.u3, orig->src.u.tcp.port,
+ &orig->dst.u3, orig->dst.u.tcp.port, &p);
+ cp = ip_vs_conn_out_get(&p);
+ 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(&p);
+ 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(ip_vs_conn_net(cp), 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));
+ }
+}
+
Code Review / kvmfornfv.git / blobdiff