Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 | /*
* 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));
}
}
|