[PATCH] netfilter: nf_nat: Support fullcone NAT

From: Paul Menzel
Date: Fri Nov 06 2020 - 17:03:43 EST

From: Kiran Kella <kiran.kella@xxxxxxxxxxxx>

Changes done in the kernel to ensure 3-tuple uniqueness of the conntrack
entries for the fullcone nat functionality.

* Hashlist is maintained for the 3-tuple unique keys (Protocol/Source
IP/Port) for all the conntrack entries.

* When NAT table rules are created with the fullcone option, the
SNAT/POSTROUTING stage ensures the ports from the pool are picked up in
such a way that the 3-tuple is uniquely assigned.

* In the DNAT/POSTROUTING stage, the fullcone behavior is ensured by checking
and reusing the 3-tuple for the Source IP/Port in the original direction.

* When the pool is exhausted of the 3-tuple assignments, the packets are
dropped, else, they will be going out of the router they being 5-tuple
unique (which is not intended).

* Passing fullcone option using iptables is part of another PR (in
sonic-buildimage repo).

The kernel changes mentioned above are done to counter the challenges
explained in the section *3.4.2.1 Handling NAT model mismatch between
the ASIC and the Kernel* in the NAT HLD [1].

[1]: https://github.com/kirankella/SONiC/blob/nat_doc_changes/doc/nat/nat_design_spec.md

[Add to SONiC in https://github.com/Azure/sonic-linux-kernel/pull/100]
Signed-off-by: Kiran Kella <kiran.kella@xxxxxxxxxxxx>
[forward port to Linux v4.19, https://github.com/Azure/sonic-linux-kernel/pull/147]
Signed-off-by: Akhilesh Samineni <akhilesh.samineni@xxxxxxxxxxxx>
Signed-off-by: Paul Menzel <pmenzel@xxxxxxxxxxxxx>
---
Dear Linux folks,


This is taken from switch network operating system (NOS) SONiCâ??s Linux
repository, where the support was added in September 2019 [1], and
forwarded ported to Linux 4.19 by Akhilesh in June 2020 [2].

I am sending it upstream as a request for comments, before effort is put
into forward porting it to Linux master.


Kind regards,

Paul


[1]: https://github.com/Azure/sonic-linux-kernel/pull/100
[2]: https://github.com/Azure/sonic-linux-kernel/pull/147

include/net/netfilter/nf_conntrack.h | 3 +
include/net/netfilter/nf_nat.h | 6 +
include/net/netfilter/nf_nat_l4proto.h | 12 +-
include/uapi/linux/netfilter/nf_nat.h | 1 +
net/ipv4/netfilter/nf_nat_proto_gre.c | 8 +-
net/ipv4/netfilter/nf_nat_proto_icmp.c | 6 +-
net/ipv6/netfilter/nf_nat_proto_icmpv6.c | 5 +-
net/netfilter/nf_nat_core.c | 173 ++++++++++++++++++++---
net/netfilter/nf_nat_proto_common.c | 32 +++--
net/netfilter/nf_nat_proto_dccp.c | 6 +-
net/netfilter/nf_nat_proto_sctp.c | 6 +-
net/netfilter/nf_nat_proto_tcp.c | 6 +-
net/netfilter/nf_nat_proto_udp.c | 12 +-
net/netfilter/nf_nat_proto_unknown.c | 4 +-
14 files changed, 220 insertions(+), 60 deletions(-)

diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index f45141bdbb83..64b9293a31f6 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h
@@ -84,6 +84,9 @@ struct nf_conn {
#if IS_ENABLED(CONFIG_NF_NAT)
struct hlist_node nat_bysource;
#endif
+ /* To optionally ensure 3-tuple uniqueness on the translated source */
+ struct hlist_node nat_by_manip_src;
+
/* all members below initialized via memset */
u8 __nfct_init_offset[0];

diff --git a/include/net/netfilter/nf_nat.h b/include/net/netfilter/nf_nat.h
index a17eb2f8d40e..7c3cc3c7b35f 100644
--- a/include/net/netfilter/nf_nat.h
+++ b/include/net/netfilter/nf_nat.h
@@ -51,6 +51,12 @@ struct nf_conn_nat *nf_ct_nat_ext_add(struct nf_conn *ct);
int nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
const struct nf_conn *ignored_conntrack);

+/* Is this 3-tuple already taken? (not by us)*/
+int
+nf_nat_used_3_tuple(const struct nf_conntrack_tuple *tuple,
+ const struct nf_conn *ignored_conntrack,
+ enum nf_nat_manip_type maniptype);
+
static inline struct nf_conn_nat *nfct_nat(const struct nf_conn *ct)
{
#if defined(CONFIG_NF_NAT) || defined(CONFIG_NF_NAT_MODULE)
diff --git a/include/net/netfilter/nf_nat_l4proto.h b/include/net/netfilter/nf_nat_l4proto.h
index b4d6b29bca62..fbcbb9ad9e4b 100644
--- a/include/net/netfilter/nf_nat_l4proto.h
+++ b/include/net/netfilter/nf_nat_l4proto.h
@@ -32,7 +32,7 @@ struct nf_nat_l4proto {
* possible. Per-protocol part of tuple is initialized to the
* incoming packet.
*/
- void (*unique_tuple)(const struct nf_nat_l3proto *l3proto,
+ int (*unique_tuple)(const struct nf_nat_l3proto *l3proto,
struct nf_conntrack_tuple *tuple,
const struct nf_nat_range2 *range,
enum nf_nat_manip_type maniptype,
@@ -70,11 +70,11 @@ bool nf_nat_l4proto_in_range(const struct nf_conntrack_tuple *tuple,
const union nf_conntrack_man_proto *min,
const union nf_conntrack_man_proto *max);

-void nf_nat_l4proto_unique_tuple(const struct nf_nat_l3proto *l3proto,
- struct nf_conntrack_tuple *tuple,
- const struct nf_nat_range2 *range,
- enum nf_nat_manip_type maniptype,
- const struct nf_conn *ct, u16 *rover);
+int nf_nat_l4proto_unique_tuple(const struct nf_nat_l3proto *l3proto,
+ struct nf_conntrack_tuple *tuple,
+ const struct nf_nat_range2 *range,
+ enum nf_nat_manip_type maniptype,
+ const struct nf_conn *ct, u16 *rover);

int nf_nat_l4proto_nlattr_to_range(struct nlattr *tb[],
struct nf_nat_range2 *range);
diff --git a/include/uapi/linux/netfilter/nf_nat.h b/include/uapi/linux/netfilter/nf_nat.h
index 4a95c0db14d4..1cda390e17c6 100644
--- a/include/uapi/linux/netfilter/nf_nat.h
+++ b/include/uapi/linux/netfilter/nf_nat.h
@@ -11,6 +11,7 @@
#define NF_NAT_RANGE_PERSISTENT (1 << 3)
#define NF_NAT_RANGE_PROTO_RANDOM_FULLY (1 << 4)
#define NF_NAT_RANGE_PROTO_OFFSET (1 << 5)
+#define NF_NAT_RANGE_FULLCONE (1 << 6)

#define NF_NAT_RANGE_PROTO_RANDOM_ALL \
(NF_NAT_RANGE_PROTO_RANDOM | NF_NAT_RANGE_PROTO_RANDOM_FULLY)
diff --git a/net/ipv4/netfilter/nf_nat_proto_gre.c b/net/ipv4/netfilter/nf_nat_proto_gre.c
index 00fda6331ce5..d2ca4f6003ba 100644
--- a/net/ipv4/netfilter/nf_nat_proto_gre.c
+++ b/net/ipv4/netfilter/nf_nat_proto_gre.c
@@ -38,7 +38,7 @@ MODULE_AUTHOR("Harald Welte <laforge@xxxxxxxxxxxx>");
MODULE_DESCRIPTION("Netfilter NAT protocol helper module for GRE");

/* generate unique tuple ... */
-static void
+static int
gre_unique_tuple(const struct nf_nat_l3proto *l3proto,
struct nf_conntrack_tuple *tuple,
const struct nf_nat_range2 *range,
@@ -52,7 +52,7 @@ gre_unique_tuple(const struct nf_nat_l3proto *l3proto,
/* If there is no master conntrack we are not PPTP,
do not change tuples */
if (!ct->master)
- return;
+ return 0;

if (maniptype == NF_NAT_MANIP_SRC)
keyptr = &tuple->src.u.gre.key;
@@ -73,11 +73,11 @@ gre_unique_tuple(const struct nf_nat_l3proto *l3proto,
for (i = 0; ; ++key) {
*keyptr = htons(min + key % range_size);
if (++i == range_size || !nf_nat_used_tuple(tuple, ct))
- return;
+ return 1;
}

pr_debug("%p: no NAT mapping\n", ct);
- return;
+ return 0;
}

/* manipulate a GRE packet according to maniptype */
diff --git a/net/ipv4/netfilter/nf_nat_proto_icmp.c b/net/ipv4/netfilter/nf_nat_proto_icmp.c
index 6d7cf1d79baf..403783cda503 100644
--- a/net/ipv4/netfilter/nf_nat_proto_icmp.c
+++ b/net/ipv4/netfilter/nf_nat_proto_icmp.c
@@ -27,7 +27,7 @@ icmp_in_range(const struct nf_conntrack_tuple *tuple,
ntohs(tuple->src.u.icmp.id) <= ntohs(max->icmp.id);
}

-static void
+static int
icmp_unique_tuple(const struct nf_nat_l3proto *l3proto,
struct nf_conntrack_tuple *tuple,
const struct nf_nat_range2 *range,
@@ -48,9 +48,9 @@ icmp_unique_tuple(const struct nf_nat_l3proto *l3proto,
tuple->src.u.icmp.id = htons(ntohs(range->min_proto.icmp.id) +
(id % range_size));
if (++i == range_size || !nf_nat_used_tuple(tuple, ct))
- return;
+ return 1;
}
- return;
+ return 0;
}

static bool
diff --git a/net/ipv6/netfilter/nf_nat_proto_icmpv6.c b/net/ipv6/netfilter/nf_nat_proto_icmpv6.c
index d9bf42ba44fa..7ff30a023f04 100644
--- a/net/ipv6/netfilter/nf_nat_proto_icmpv6.c
+++ b/net/ipv6/netfilter/nf_nat_proto_icmpv6.c
@@ -29,7 +29,7 @@ icmpv6_in_range(const struct nf_conntrack_tuple *tuple,
ntohs(tuple->src.u.icmp.id) <= ntohs(max->icmp.id);
}

-static void
+static int
icmpv6_unique_tuple(const struct nf_nat_l3proto *l3proto,
struct nf_conntrack_tuple *tuple,
const struct nf_nat_range2 *range,
@@ -50,8 +50,9 @@ icmpv6_unique_tuple(const struct nf_nat_l3proto *l3proto,
tuple->src.u.icmp.id = htons(ntohs(range->min_proto.icmp.id) +
(id % range_size));
if (++i == range_size || !nf_nat_used_tuple(tuple, ct))
- return;
+ return 1;
}
+ return 0;
}

static bool
diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c
index 2268b10a9dcf..1b83427a7a68 100644
--- a/net/netfilter/nf_nat_core.c
+++ b/net/netfilter/nf_nat_core.c
@@ -43,6 +43,7 @@ static const struct nf_nat_l4proto __rcu **nf_nat_l4protos[NFPROTO_NUMPROTO]
static unsigned int nat_net_id __read_mostly;

static struct hlist_head *nf_nat_bysource __read_mostly;
+static struct hlist_head *nf_nat_by_manip_src __read_mostly;
static unsigned int nf_nat_htable_size __read_mostly;
static unsigned int nf_nat_hash_rnd __read_mostly;

@@ -155,6 +156,31 @@ hash_by_src(const struct net *n, const struct nf_conntrack_tuple *tuple)
return reciprocal_scale(hash, nf_nat_htable_size);
}

+static inline unsigned int
+hash_by_dst(const struct net *n, const struct nf_conntrack_tuple *tuple)
+{
+ unsigned int hash;
+
+ get_random_once(&nf_nat_hash_rnd, sizeof(nf_nat_hash_rnd));
+
+ hash = jhash2((u32 *)&tuple->dst, sizeof(tuple->dst) / sizeof(u32),
+ tuple->dst.protonum ^ nf_nat_hash_rnd ^ net_hash_mix(n));
+
+ return reciprocal_scale(hash, nf_nat_htable_size);
+}
+
+static inline int
+same_reply_dst(const struct nf_conn *ct,
+ const struct nf_conntrack_tuple *tuple)
+{
+ const struct nf_conntrack_tuple *t;
+
+ t = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
+ return (t->dst.protonum == tuple->dst.protonum &&
+ nf_inet_addr_cmp(&t->dst.u3, &tuple->dst.u3) &&
+ t->dst.u.all == tuple->dst.u.all);
+}
+
/* Is this tuple already taken? (not by us) */
int
nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
@@ -171,7 +197,40 @@ nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
nf_ct_invert_tuplepr(&reply, tuple);
return nf_conntrack_tuple_taken(&reply, ignored_conntrack);
}
+
+/* Is this 3-tuple already taken? (not by us) */
+int
+nf_nat_used_3_tuple(const struct nf_conntrack_tuple *tuple,
+ const struct nf_conn *ignored_conntrack,
+ enum nf_nat_manip_type maniptype)
+{
+ const struct nf_conn *ct;
+ const struct nf_conntrack_zone *zone;
+ unsigned int h;
+ struct net *net = nf_ct_net(ignored_conntrack);
+
+ /* 3-tuple uniqueness is required for translated source only */
+ if (maniptype != NF_NAT_MANIP_SRC) {
+ return 0;
+ }
+ zone = nf_ct_zone(ignored_conntrack);
+
+ /* The tuple passed here is the inverted reply (with translated source) */
+ h = hash_by_src(net, tuple);
+ hlist_for_each_entry_rcu(ct, &nf_nat_by_manip_src[h], nat_by_manip_src) {
+ struct nf_conntrack_tuple reply;
+ nf_ct_invert_tuplepr(&reply, tuple);
+ /* Compare against the destination in the reply */
+ if (same_reply_dst(ct, &reply) &&
+ net_eq(net, nf_ct_net(ct)) &&
+ nf_ct_zone_equal(ct, zone, IP_CT_DIR_ORIGINAL)) {
+ return 1;
+ }
+ }
+ return 0;
+}
EXPORT_SYMBOL(nf_nat_used_tuple);
+EXPORT_SYMBOL(nf_nat_used_3_tuple);

/* If we source map this tuple so reply looks like reply_tuple, will
* that meet the constraints of range.
@@ -237,6 +296,36 @@ find_appropriate_src(struct net *net,
return 0;
}

+/* Only called for DST manip */
+static int
+find_appropriate_dst(struct net *net,
+ const struct nf_conntrack_zone *zone,
+ const struct nf_nat_l3proto *l3proto,
+ const struct nf_nat_l4proto *l4proto,
+ const struct nf_conntrack_tuple *tuple,
+ struct nf_conntrack_tuple *result)
+{
+ struct nf_conntrack_tuple reply;
+ unsigned int h;
+ const struct nf_conn *ct;
+
+ nf_ct_invert_tuplepr(&reply, tuple);
+ h = hash_by_src(net, &reply);
+
+ hlist_for_each_entry_rcu(ct, &nf_nat_by_manip_src[h], nat_by_manip_src) {
+ if (same_reply_dst(ct, tuple) &&
+ net_eq(net, nf_ct_net(ct)) &&
+ nf_ct_zone_equal(ct, zone, IP_CT_DIR_REPLY)) {
+ /* Copy destination part from original tuple. */
+ nf_ct_invert_tuplepr(result,
+ &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
+ result->src = tuple->src;
+ return 1;
+ }
+ }
+ return 0;
+}
+
/* For [FUTURE] fragmentation handling, we want the least-used
* src-ip/dst-ip/proto triple. Fairness doesn't come into it. Thus
* if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports
@@ -314,10 +403,15 @@ find_best_ips_proto(const struct nf_conntrack_zone *zone,
/* Manipulate the tuple into the range given. For NF_INET_POST_ROUTING,
* we change the source to map into the range. For NF_INET_PRE_ROUTING
* and NF_INET_LOCAL_OUT, we change the destination to map into the
- * range. It might not be possible to get a unique tuple, but we try.
+ * range. It might not be possible to get a unique 5-tuple, but we try.
* At worst (or if we race), we will end up with a final duplicate in
- * __ip_conntrack_confirm and drop the packet. */
-static void
+ * __ip_conntrack_confirm and drop the packet.
+ * If the range is of type fullcone, if we end up with a 3-tuple
+ * duplicate, we do not wait till the packet reaches the
+ * nf_conntrack_confirm to drop the packet. Instead return the packet
+ * to be dropped at this stage.
+ */
+static int
get_unique_tuple(struct nf_conntrack_tuple *tuple,
const struct nf_conntrack_tuple *orig_tuple,
const struct nf_nat_range2 *range,
@@ -327,8 +421,11 @@ get_unique_tuple(struct nf_conntrack_tuple *tuple,
const struct nf_conntrack_zone *zone;
const struct nf_nat_l3proto *l3proto;
const struct nf_nat_l4proto *l4proto;
+ struct nf_nat_range2 nat_range;
struct net *net = nf_ct_net(ct);

+ memcpy(&nat_range, range, sizeof(struct nf_nat_range2));
+
zone = nf_ct_zone(ct);

rcu_read_lock();
@@ -345,48 +442,77 @@ get_unique_tuple(struct nf_conntrack_tuple *tuple,
* manips not an issue.
*/
if (maniptype == NF_NAT_MANIP_SRC &&
- !(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL)) {
+ !(nat_range.flags & NF_NAT_RANGE_PROTO_RANDOM_ALL)) {
/* try the original tuple first */
- if (in_range(l3proto, l4proto, orig_tuple, range)) {
+ if (in_range(l3proto, l4proto, orig_tuple, &nat_range)) {
if (!nf_nat_used_tuple(orig_tuple, ct)) {
*tuple = *orig_tuple;
goto out;
}
} else if (find_appropriate_src(net, zone, l3proto, l4proto,
- orig_tuple, tuple, range)) {
+ orig_tuple, tuple, &nat_range)) {
pr_debug("get_unique_tuple: Found current src map\n");
if (!nf_nat_used_tuple(tuple, ct))
goto out;
}
}

+ if (maniptype == NF_NAT_MANIP_DST) {
+ if (nat_range.flags & NF_NAT_RANGE_FULLCONE) {
+ /* Destination IP range does not apply when fullcone flag is set. */
+ nat_range.min_addr.ip = nat_range.max_addr.ip = orig_tuple->dst.u3.ip;
+ nat_range.min_proto.all = nat_range.max_proto.all = 0;
+
+ /* If this dstip/proto/dst-proto-part is mapped currently
+ * as a translated source for a given tuple, use that
+ */
+ if (find_appropriate_dst(net, zone, l3proto, l4proto,
+ orig_tuple, tuple)) {
+ if (!nf_nat_used_tuple(tuple, ct)) {
+ goto out;
+ }
+ } else {
+ /* If not mapped, proceed with the original tuple */
+ *tuple = *orig_tuple;
+ goto out;
+ }
+ }
+ }
+
/* 2) Select the least-used IP/proto combination in the given range */
*tuple = *orig_tuple;
- find_best_ips_proto(zone, tuple, range, ct, maniptype);
+ find_best_ips_proto(zone, tuple, &nat_range, ct, maniptype);

/* 3) The per-protocol part of the manip is made to map into
* the range to make a unique tuple.
*/

/* Only bother mapping if it's not already in range and unique */
- if (!(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL)) {
- if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
- if (!(range->flags & NF_NAT_RANGE_PROTO_OFFSET) &&
+ if (!(nat_range.flags & NF_NAT_RANGE_PROTO_RANDOM_ALL)) {
+ if (nat_range.flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
+ if (!(nat_range.flags & NF_NAT_RANGE_PROTO_OFFSET) &&
l4proto->in_range(tuple, maniptype,
- &range->min_proto,
- &range->max_proto) &&
- (range->min_proto.all == range->max_proto.all ||
- !nf_nat_used_tuple(tuple, ct)))
- goto out;
+ &(nat_range.min_proto),
+ &(nat_range.max_proto))) {
+ if (nat_range.flags & NF_NAT_RANGE_FULLCONE) {
+ if (!nf_nat_used_3_tuple(tuple, ct, maniptype))
+ goto out;
+ } else {
+ if ((nat_range.min_proto.all == nat_range.max_proto.all) ||
+ !nf_nat_used_tuple(tuple, ct))
+ goto out;
+ }
+ }
} else if (!nf_nat_used_tuple(tuple, ct)) {
goto out;
}
}

/* Last chance: get protocol to try to obtain unique tuple. */
- l4proto->unique_tuple(l3proto, tuple, range, maniptype, ct);
+ return l4proto->unique_tuple(l3proto, tuple, &nat_range, maniptype, ct);
out:
rcu_read_unlock();
+ return 1;
}

struct nf_conn_nat *nf_ct_nat_ext_add(struct nf_conn *ct)
@@ -428,7 +554,9 @@ nf_nat_setup_info(struct nf_conn *ct,
nf_ct_invert_tuplepr(&curr_tuple,
&ct->tuplehash[IP_CT_DIR_REPLY].tuple);

- get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype);
+ if (! get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype)) {
+ return NF_DROP;
+ }

if (!nf_ct_tuple_equal(&new_tuple, &curr_tuple)) {
struct nf_conntrack_tuple reply;
@@ -450,12 +578,16 @@ nf_nat_setup_info(struct nf_conn *ct,

if (maniptype == NF_NAT_MANIP_SRC) {
unsigned int srchash;
+ unsigned int manip_src_hash;
spinlock_t *lock;

+ manip_src_hash = hash_by_src(net, &new_tuple);
srchash = hash_by_src(net,
&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
lock = &nf_nat_locks[srchash % CONNTRACK_LOCKS];
spin_lock_bh(lock);
+ hlist_add_head_rcu(&ct->nat_by_manip_src,
+ &nf_nat_by_manip_src[manip_src_hash]);
hlist_add_head_rcu(&ct->nat_bysource,
&nf_nat_bysource[srchash]);
spin_unlock_bh(lock);
@@ -644,6 +776,7 @@ static void __nf_nat_cleanup_conntrack(struct nf_conn *ct)
h = hash_by_src(nf_ct_net(ct), &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
spin_lock_bh(&nf_nat_locks[h % CONNTRACK_LOCKS]);
hlist_del_rcu(&ct->nat_bysource);
+ hlist_del_rcu(&ct->nat_by_manip_src);
spin_unlock_bh(&nf_nat_locks[h % CONNTRACK_LOCKS]);
}

@@ -1055,9 +1188,14 @@ static int __init nf_nat_init(void)
if (!nf_nat_bysource)
return -ENOMEM;

+ nf_nat_by_manip_src = nf_ct_alloc_hashtable(&nf_nat_htable_size, 0);
+ if (!nf_nat_by_manip_src)
+ return -ENOMEM;
+
ret = nf_ct_extend_register(&nat_extend);
if (ret < 0) {
kvfree(nf_nat_bysource);
+ kvfree(nf_nat_by_manip_src);
pr_err("Unable to register extension\n");
return ret;
}
@@ -1096,6 +1234,7 @@ static void __exit nf_nat_cleanup(void)
kfree(nf_nat_l4protos[i]);
synchronize_net();
kvfree(nf_nat_bysource);
+ kvfree(nf_nat_by_manip_src);
unregister_pernet_subsys(&nat_net_ops);
}

diff --git a/net/netfilter/nf_nat_proto_common.c b/net/netfilter/nf_nat_proto_common.c
index 5d849d835561..6ee918302a02 100644
--- a/net/netfilter/nf_nat_proto_common.c
+++ b/net/netfilter/nf_nat_proto_common.c
@@ -34,12 +34,12 @@ bool nf_nat_l4proto_in_range(const struct nf_conntrack_tuple *tuple,
}
EXPORT_SYMBOL_GPL(nf_nat_l4proto_in_range);

-void nf_nat_l4proto_unique_tuple(const struct nf_nat_l3proto *l3proto,
- struct nf_conntrack_tuple *tuple,
- const struct nf_nat_range2 *range,
- enum nf_nat_manip_type maniptype,
- const struct nf_conn *ct,
- u16 *rover)
+int nf_nat_l4proto_unique_tuple(const struct nf_nat_l3proto *l3proto,
+ struct nf_conntrack_tuple *tuple,
+ const struct nf_nat_range2 *range,
+ enum nf_nat_manip_type maniptype,
+ const struct nf_conn *ct,
+ u16 *rover)
{
unsigned int range_size, min, max, i;
__be16 *portptr;
@@ -54,7 +54,7 @@ void nf_nat_l4proto_unique_tuple(const struct nf_nat_l3proto *l3proto,
if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)) {
/* If it's dst rewrite, can't change port */
if (maniptype == NF_NAT_MANIP_DST)
- return;
+ return 0;

if (ntohs(*portptr) < 1024) {
/* Loose convention: >> 512 is credential passing */
@@ -87,17 +87,27 @@ void nf_nat_l4proto_unique_tuple(const struct nf_nat_l3proto *l3proto,
off = (ntohs(*portptr) - ntohs(range->base_proto.all));
} else {
off = *rover;
+ if ((range->flags & NF_NAT_RANGE_FULLCONE) && (maniptype == NF_NAT_MANIP_SRC)) {
+ /* Try from the next L4 port in the range */
+ off++;
+ }
}

- for (i = 0; ; ++off) {
+ for (i = 0; (i != range_size); ++i, ++off) {
*portptr = htons(min + off % range_size);
- if (++i != range_size && nf_nat_used_tuple(tuple, ct))
- continue;
+ if ((range->flags & NF_NAT_RANGE_FULLCONE) && (maniptype == NF_NAT_MANIP_SRC)) {
+ if (nf_nat_used_3_tuple(tuple, ct, maniptype))
+ continue;
+ } else {
+ if (nf_nat_used_tuple(tuple, ct))
+ continue;
+ }
if (!(range->flags & (NF_NAT_RANGE_PROTO_RANDOM_ALL|
NF_NAT_RANGE_PROTO_OFFSET)))
*rover = off;
- return;
+ return 1;
}
+ return 0;
}
EXPORT_SYMBOL_GPL(nf_nat_l4proto_unique_tuple);

diff --git a/net/netfilter/nf_nat_proto_dccp.c b/net/netfilter/nf_nat_proto_dccp.c
index 67ea0d83aa5a..68ef70bb55df 100644
--- a/net/netfilter/nf_nat_proto_dccp.c
+++ b/net/netfilter/nf_nat_proto_dccp.c
@@ -20,15 +20,15 @@

static u_int16_t dccp_port_rover;

-static void
+static int
dccp_unique_tuple(const struct nf_nat_l3proto *l3proto,
struct nf_conntrack_tuple *tuple,
const struct nf_nat_range2 *range,
enum nf_nat_manip_type maniptype,
const struct nf_conn *ct)
{
- nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
- &dccp_port_rover);
+ return nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
+ &dccp_port_rover);
}

static bool
diff --git a/net/netfilter/nf_nat_proto_sctp.c b/net/netfilter/nf_nat_proto_sctp.c
index 1c5d9b65fbba..a9d9070c36c8 100644
--- a/net/netfilter/nf_nat_proto_sctp.c
+++ b/net/netfilter/nf_nat_proto_sctp.c
@@ -14,15 +14,15 @@

static u_int16_t nf_sctp_port_rover;

-static void
+static int
sctp_unique_tuple(const struct nf_nat_l3proto *l3proto,
struct nf_conntrack_tuple *tuple,
const struct nf_nat_range2 *range,
enum nf_nat_manip_type maniptype,
const struct nf_conn *ct)
{
- nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
- &nf_sctp_port_rover);
+ return nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
+ &nf_sctp_port_rover);
}

static bool
diff --git a/net/netfilter/nf_nat_proto_tcp.c b/net/netfilter/nf_nat_proto_tcp.c
index f15fcd475f98..1b039055421f 100644
--- a/net/netfilter/nf_nat_proto_tcp.c
+++ b/net/netfilter/nf_nat_proto_tcp.c
@@ -20,15 +20,15 @@

static u16 tcp_port_rover;

-static void
+static int
tcp_unique_tuple(const struct nf_nat_l3proto *l3proto,
struct nf_conntrack_tuple *tuple,
const struct nf_nat_range2 *range,
enum nf_nat_manip_type maniptype,
const struct nf_conn *ct)
{
- nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
- &tcp_port_rover);
+ return nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
+ &tcp_port_rover);
}

static bool
diff --git a/net/netfilter/nf_nat_proto_udp.c b/net/netfilter/nf_nat_proto_udp.c
index 5790f70a83b2..0b26bb52aef6 100644
--- a/net/netfilter/nf_nat_proto_udp.c
+++ b/net/netfilter/nf_nat_proto_udp.c
@@ -19,15 +19,15 @@

static u16 udp_port_rover;

-static void
+static int
udp_unique_tuple(const struct nf_nat_l3proto *l3proto,
struct nf_conntrack_tuple *tuple,
const struct nf_nat_range2 *range,
enum nf_nat_manip_type maniptype,
const struct nf_conn *ct)
{
- nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
- &udp_port_rover);
+ return nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
+ &udp_port_rover);
}

static void
@@ -97,15 +97,15 @@ static bool udplite_manip_pkt(struct sk_buff *skb,
return true;
}

-static void
+static int
udplite_unique_tuple(const struct nf_nat_l3proto *l3proto,
struct nf_conntrack_tuple *tuple,
const struct nf_nat_range2 *range,
enum nf_nat_manip_type maniptype,
const struct nf_conn *ct)
{
- nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
- &udplite_port_rover);
+ return nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
+ &udplite_port_rover);
}

const struct nf_nat_l4proto nf_nat_l4proto_udplite = {
diff --git a/net/netfilter/nf_nat_proto_unknown.c b/net/netfilter/nf_nat_proto_unknown.c
index c5db3e251232..377a2938cd79 100644
--- a/net/netfilter/nf_nat_proto_unknown.c
+++ b/net/netfilter/nf_nat_proto_unknown.c
@@ -25,7 +25,7 @@ static bool unknown_in_range(const struct nf_conntrack_tuple *tuple,
return true;
}

-static void unknown_unique_tuple(const struct nf_nat_l3proto *l3proto,
+static int unknown_unique_tuple(const struct nf_nat_l3proto *l3proto,
struct nf_conntrack_tuple *tuple,
const struct nf_nat_range2 *range,
enum nf_nat_manip_type maniptype,
@@ -34,7 +34,7 @@ static void unknown_unique_tuple(const struct nf_nat_l3proto *l3proto,
/* Sorry: we can't help you; if it's not unique, we can't frob
* anything.
*/
- return;
+ return 0;
}

static bool