netfilter: nf_conntrack: add support for "conntrack zones"
Normally, each connection needs a unique identity. Conntrack zones allow
to specify a numerical zone using the CT target, connections in different
zones can use the same identity.
Example:
iptables -t raw -A PREROUTING -i veth0 -j CT --zone 1
iptables -t raw -A OUTPUT -o veth1 -j CT --zone 1
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/ipv4/netfilter/nf_nat_core.c b/net/ipv4/netfilter/nf_nat_core.c
index 26066a2..4595281 100644
--- a/net/ipv4/netfilter/nf_nat_core.c
+++ b/net/ipv4/netfilter/nf_nat_core.c
@@ -30,6 +30,7 @@
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_l3proto.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
+#include <net/netfilter/nf_conntrack_zones.h>
static DEFINE_SPINLOCK(nf_nat_lock);
@@ -69,13 +70,14 @@
/* We keep an extra hash for each conntrack, for fast searching. */
static inline unsigned int
-hash_by_src(const struct net *net, const struct nf_conntrack_tuple *tuple)
+hash_by_src(const struct net *net, u16 zone,
+ const struct nf_conntrack_tuple *tuple)
{
unsigned int hash;
/* Original src, to ensure we map it consistently if poss. */
hash = jhash_3words((__force u32)tuple->src.u3.ip,
- (__force u32)tuple->src.u.all,
+ (__force u32)tuple->src.u.all ^ zone,
tuple->dst.protonum, 0);
return ((u64)hash * net->ipv4.nat_htable_size) >> 32;
}
@@ -139,12 +141,12 @@
/* Only called for SRC manip */
static int
-find_appropriate_src(struct net *net,
+find_appropriate_src(struct net *net, u16 zone,
const struct nf_conntrack_tuple *tuple,
struct nf_conntrack_tuple *result,
const struct nf_nat_range *range)
{
- unsigned int h = hash_by_src(net, tuple);
+ unsigned int h = hash_by_src(net, zone, tuple);
const struct nf_conn_nat *nat;
const struct nf_conn *ct;
const struct hlist_node *n;
@@ -152,7 +154,7 @@
rcu_read_lock();
hlist_for_each_entry_rcu(nat, n, &net->ipv4.nat_bysource[h], bysource) {
ct = nat->ct;
- if (same_src(ct, tuple)) {
+ if (same_src(ct, tuple) && nf_ct_zone(ct) == zone) {
/* Copy source part from reply tuple. */
nf_ct_invert_tuplepr(result,
&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
@@ -175,7 +177,7 @@
the ip with the lowest src-ip/dst-ip/proto usage.
*/
static void
-find_best_ips_proto(struct nf_conntrack_tuple *tuple,
+find_best_ips_proto(u16 zone, struct nf_conntrack_tuple *tuple,
const struct nf_nat_range *range,
const struct nf_conn *ct,
enum nf_nat_manip_type maniptype)
@@ -209,7 +211,7 @@
maxip = ntohl(range->max_ip);
j = jhash_2words((__force u32)tuple->src.u3.ip,
range->flags & IP_NAT_RANGE_PERSISTENT ?
- 0 : (__force u32)tuple->dst.u3.ip, 0);
+ 0 : (__force u32)tuple->dst.u3.ip ^ zone, 0);
j = ((u64)j * (maxip - minip + 1)) >> 32;
*var_ipp = htonl(minip + j);
}
@@ -229,6 +231,7 @@
{
struct net *net = nf_ct_net(ct);
const struct nf_nat_protocol *proto;
+ u16 zone = nf_ct_zone(ct);
/* 1) If this srcip/proto/src-proto-part is currently mapped,
and that same mapping gives a unique tuple within the given
@@ -239,7 +242,7 @@
manips not an issue. */
if (maniptype == IP_NAT_MANIP_SRC &&
!(range->flags & IP_NAT_RANGE_PROTO_RANDOM)) {
- if (find_appropriate_src(net, orig_tuple, tuple, range)) {
+ if (find_appropriate_src(net, zone, orig_tuple, tuple, range)) {
pr_debug("get_unique_tuple: Found current src map\n");
if (!nf_nat_used_tuple(tuple, ct))
return;
@@ -249,7 +252,7 @@
/* 2) Select the least-used IP/proto combination in the given
range. */
*tuple = *orig_tuple;
- find_best_ips_proto(tuple, range, ct, maniptype);
+ find_best_ips_proto(zone, tuple, range, ct, maniptype);
/* 3) The per-protocol part of the manip is made to map into
the range to make a unique tuple. */
@@ -327,7 +330,8 @@
if (have_to_hash) {
unsigned int srchash;
- srchash = hash_by_src(net, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
+ srchash = hash_by_src(net, nf_ct_zone(ct),
+ &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
spin_lock_bh(&nf_nat_lock);
/* nf_conntrack_alter_reply might re-allocate exntension aera */
nat = nfct_nat(ct);