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Diffstat (limited to 'net/netfilter/ipvs/ip_vs_ftp.c')
-rw-r--r--net/netfilter/ipvs/ip_vs_ftp.c176
1 files changed, 164 insertions, 12 deletions
diff --git a/net/netfilter/ipvs/ip_vs_ftp.c b/net/netfilter/ipvs/ip_vs_ftp.c
index 2ae747a376a..f228a17ec64 100644
--- a/net/netfilter/ipvs/ip_vs_ftp.c
+++ b/net/netfilter/ipvs/ip_vs_ftp.c
@@ -20,6 +20,17 @@
*
* Author: Wouter Gadeyne
*
+ *
+ * Code for ip_vs_expect_related and ip_vs_expect_callback is taken from
+ * http://www.ssi.bg/~ja/nfct/:
+ *
+ * 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) 2003-2008
+ * Julian Anastasov
*/
#define KMSG_COMPONENT "IPVS"
@@ -32,6 +43,9 @@
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/netfilter.h>
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_expect.h>
+#include <net/netfilter/nf_nat_helper.h>
#include <linux/gfp.h>
#include <net/protocol.h>
#include <net/tcp.h>
@@ -43,6 +57,16 @@
#define SERVER_STRING "227 Entering Passive Mode ("
#define CLIENT_STRING "PORT "
+#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
/*
* List of ports (up to IP_VS_APP_MAX_PORTS) to be handled by helper
@@ -123,6 +147,119 @@ static int ip_vs_ftp_get_addrport(char *data, char *data_limit,
return 1;
}
+/*
+ * Called from init_conntrack() as expectfn handler.
+ */
+static void
+ip_vs_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.
+ */
+static void
+ip_vs_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;
+
+ BUG_ON(!ct || ct == &nf_conntrack_untracked);
+
+ exp = nf_ct_expect_alloc(ct);
+ if (!exp)
+ return;
+
+ if (from_rs)
+ nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT,
+ nf_ct_l3num(ct), &cp->daddr, &cp->caddr,
+ proto, port, &cp->cport);
+ else
+ nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT,
+ nf_ct_l3num(ct), &cp->caddr, &cp->vaddr,
+ proto, port, &cp->vport);
+
+ exp->expectfn = ip_vs_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);
+}
/*
* Look at outgoing ftp packets to catch the response to a PASV command
@@ -149,7 +286,9 @@ static int ip_vs_ftp_out(struct ip_vs_app *app, struct ip_vs_conn *cp,
struct ip_vs_conn *n_cp;
char buf[24]; /* xxx.xxx.xxx.xxx,ppp,ppp\000 */
unsigned buf_len;
- int ret;
+ int ret = 0;
+ enum ip_conntrack_info ctinfo;
+ struct nf_conn *ct;
#ifdef CONFIG_IP_VS_IPV6
/* This application helper doesn't work with IPv6 yet,
@@ -219,19 +358,26 @@ static int ip_vs_ftp_out(struct ip_vs_app *app, struct ip_vs_conn *cp,
buf_len = strlen(buf);
+ ct = nf_ct_get(skb, &ctinfo);
+ if (ct && !nf_ct_is_untracked(ct)) {
+ /* If mangling fails this function will return 0
+ * which will cause the packet to be dropped.
+ * Mangling can only fail under memory pressure,
+ * hopefully it will succeed on the retransmitted
+ * packet.
+ */
+ ret = nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
+ start-data, end-start,
+ buf, buf_len);
+ if (ret)
+ ip_vs_expect_related(skb, ct, n_cp,
+ IPPROTO_TCP, NULL, 0);
+ }
+
/*
- * Calculate required delta-offset to keep TCP happy
+ * Not setting 'diff' is intentional, otherwise the sequence
+ * would be adjusted twice.
*/
- *diff = buf_len - (end-start);
-
- if (*diff == 0) {
- /* simply replace it with new passive address */
- memcpy(start, buf, buf_len);
- ret = 1;
- } else {
- ret = !ip_vs_skb_replace(skb, GFP_ATOMIC, start,
- end-start, buf, buf_len);
- }
cp->app_data = NULL;
ip_vs_tcp_conn_listen(n_cp);
@@ -263,6 +409,7 @@ static int ip_vs_ftp_in(struct ip_vs_app *app, struct ip_vs_conn *cp,
union nf_inet_addr to;
__be16 port;
struct ip_vs_conn *n_cp;
+ struct nf_conn *ct;
#ifdef CONFIG_IP_VS_IPV6
/* This application helper doesn't work with IPv6 yet,
@@ -349,6 +496,11 @@ static int ip_vs_ftp_in(struct ip_vs_app *app, struct ip_vs_conn *cp,
ip_vs_control_add(n_cp, cp);
}
+ ct = (struct nf_conn *)skb->nfct;
+ if (ct && ct != &nf_conntrack_untracked)
+ ip_vs_expect_related(skb, ct, n_cp,
+ IPPROTO_TCP, &n_cp->dport, 1);
+
/*
* Move tunnel to listen state
*/
generated by cgit v1.2.3 (git 2.39.1) at 2024-04-19 17:26:05 +0000