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- /*
- * 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_ipvs(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(cp->ipvs->net, &nf_ct_zone_dflt, &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));
- }
- }
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