[NETFILTER]: Add support for permanent expectations

A permanent expectation exists until timeing out and can expect
multiple related connections.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

7 files changed, 18 insertions, 4 deletions

diff --git a/include/linux/netfilter_ipv4/ip_conntrack.h b/include/linux/netfilter_ipv4/ip_conntrack.h
index 088742befe49..7e033e9271a8 100644
--- a/include/linux/netfilter_ipv4/ip_conntrack.h
+++ b/include/linux/netfilter_ipv4/ip_conntrack.h
@@ -263,6 +263,9 @@ struct ip_conntrack_expect
         /* Unique ID */
         unsigned int id;
 
+        /* Flags */
+        unsigned int flags;
+
 #ifdef CONFIG_IP_NF_NAT_NEEDED
         /* This is the original per-proto part, used to map the
          * expected connection the way the recipient expects. */
@@ -272,6 +275,8 @@ struct ip_conntrack_expect
 #endif
 };
 
+#define IP_CT_EXPECT_PERMANENT  0x1
+
 static inline struct ip_conntrack *
 tuplehash_to_ctrack(const struct ip_conntrack_tuple_hash *hash)
 {
diff --git a/net/ipv4/netfilter/ip_conntrack_amanda.c b/net/ipv4/netfilter/ip_conntrack_amanda.c
index be4c9eb3243f..dc20881004bc 100644
--- a/net/ipv4/netfilter/ip_conntrack_amanda.c
+++ b/net/ipv4/netfilter/ip_conntrack_amanda.c
@@ -108,6 +108,7 @@ static int help(struct sk_buff **pskb,
                 }
 
                 exp->expectfn = NULL;
+                exp->flags = 0;
 
                 exp->tuple.src.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip;
                 exp->tuple.src.u.tcp.port = 0;
diff --git a/net/ipv4/netfilter/ip_conntrack_core.c b/net/ipv4/netfilter/ip_conntrack_core.c
index a0648600190e..e23e8ca476c0 100644
--- a/net/ipv4/netfilter/ip_conntrack_core.c
+++ b/net/ipv4/netfilter/ip_conntrack_core.c
@@ -264,10 +264,14 @@ find_expectation(const struct ip_conntrack_tuple *tuple)
                    master ct never got confirmed, we'd hold a reference to it
                    and weird things would happen to future packets). */
                 if (ip_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask)
-                    && is_confirmed(i->master)
-                    && del_timer(&i->timeout)) {
-                        unlink_expect(i);
-                        return i;
+                    && is_confirmed(i->master)) {
+                        if (i->flags & IP_CT_EXPECT_PERMANENT) {
+                                atomic_inc(&i->use);
+                                return i;
+                        } else if (del_timer(&i->timeout)) {
+                                unlink_expect(i);
+                                return i;
+                        }
                 }
         }
         return NULL;
diff --git a/net/ipv4/netfilter/ip_conntrack_ftp.c b/net/ipv4/netfilter/ip_conntrack_ftp.c
index 3a2627db1729..1b79ec36085f 100644
--- a/net/ipv4/netfilter/ip_conntrack_ftp.c
+++ b/net/ipv4/netfilter/ip_conntrack_ftp.c
@@ -421,6 +421,7 @@ static int help(struct sk_buff **pskb,
                   { 0xFFFFFFFF, { .tcp = { 0xFFFF } }, 0xFF }});
 
         exp->expectfn = NULL;
+        exp->flags = 0;
 
         /* Now, NAT might want to mangle the packet, and register the
          * (possibly changed) expectation itself. */
diff --git a/net/ipv4/netfilter/ip_conntrack_irc.c b/net/ipv4/netfilter/ip_conntrack_irc.c
index 25438eec21a1..d7a8a98c05e1 100644
--- a/net/ipv4/netfilter/ip_conntrack_irc.c
+++ b/net/ipv4/netfilter/ip_conntrack_irc.c
@@ -221,6 +221,7 @@ static int help(struct sk_buff **pskb,
                                 { { 0, { 0 } },
                                   { 0xFFFFFFFF, { .tcp = { 0xFFFF } }, 0xFF }});
                         exp->expectfn = NULL;
+                        exp->flags = 0;
                         if (ip_nat_irc_hook)
                                 ret = ip_nat_irc_hook(pskb, ctinfo, 
                                                       addr_beg_p - ib_ptr,
diff --git a/net/ipv4/netfilter/ip_conntrack_netlink.c b/net/ipv4/netfilter/ip_conntrack_netlink.c
index a4e9278db4ed..3dc3a7bab3b4 100644
--- a/net/ipv4/netfilter/ip_conntrack_netlink.c
+++ b/net/ipv4/netfilter/ip_conntrack_netlink.c
@@ -1413,6 +1413,7 @@ ctnetlink_create_expect(struct nfattr *cda[])
         }
         
         exp->expectfn = NULL;
+        exp->flags = 0;
         exp->master = ct;
         memcpy(&exp->tuple, &tuple, sizeof(struct ip_conntrack_tuple));
         memcpy(&exp->mask, &mask, sizeof(struct ip_conntrack_tuple));
diff --git a/net/ipv4/netfilter/ip_conntrack_tftp.c b/net/ipv4/netfilter/ip_conntrack_tftp.c
index f8ff170f390a..d2b590533452 100644
--- a/net/ipv4/netfilter/ip_conntrack_tftp.c
+++ b/net/ipv4/netfilter/ip_conntrack_tftp.c
@@ -75,6 +75,7 @@ static int tftp_help(struct sk_buff **pskb,
                 exp->mask.dst.u.udp.port = 0xffff;
                 exp->mask.dst.protonum = 0xff;
                 exp->expectfn = NULL;
+                exp->flags = 0;
 
                 DEBUGP("expect: ");
                 DUMP_TUPLE(&exp->tuple);