tipc: introduce TIPC encryption & authentication

This commit offers an option to encrypt and authenticate all messaging,
including the neighbor discovery messages. The currently most advanced
algorithm supported is the AEAD AES-GCM (like IPSec or TLS). All
encryption/decryption is done at the bearer layer, just before leaving
or after entering TIPC.

Supported features:
- Encryption & authentication of all TIPC messages (header + data);
- Two symmetric-key modes: Cluster and Per-node;
- Automatic key switching;
- Key-expired revoking (sequence number wrapped);
- Lock-free encryption/decryption (RCU);
- Asynchronous crypto, Intel AES-NI supported;
- Multiple cipher transforms;
- Logs & statistics;

Two key modes:
- Cluster key mode: One single key is used for both TX & RX in all
nodes in the cluster.
- Per-node key mode: Each nodes in the cluster has one specific TX key.
For RX, a node requires its peers' TX key to be able to decrypt the
messages from those peers.

Key setting from user-space is performed via netlink by a user program
(e.g. the iproute2 'tipc' tool).

Internal key state machine:

                                 Attach    Align(RX)
                                     +-+   +-+
                                     | V   | V
        +---------+      Attach     +---------+
        |  IDLE   |---------------->| PENDING |(user = 0)
        +---------+                 +---------+
           A   A                   Switch|  A
           |   |                         |  |
           |   | Free(switch/revoked)    |  |
     (Free)|   +----------------------+  |  |Timeout
           |              (TX)        |  |  |(RX)
           |                          |  |  |
           |                          |  v  |
        +---------+      Switch     +---------+
        | PASSIVE |<----------------| ACTIVE  |
        +---------+       (RX)      +---------+
        (user = 1)                  (user >= 1)

The number of TFMs is 10 by default and can be changed via the procfs
'net/tipc/max_tfms'. At this moment, as for simplicity, this file is
also used to print the crypto statistics at runtime:

echo 0xfff1 > /proc/sys/net/tipc/max_tfms

The patch defines a new TIPC version (v7) for the encryption message (-
backward compatibility as well). The message is basically encapsulated
as follows:

   +----------------------------------------------------------+
   | TIPCv7 encryption  | Original TIPCv2    | Authentication |
   | header             | packet (encrypted) | Tag            |
   +----------------------------------------------------------+

The throughput is about ~40% for small messages (compared with non-
encryption) and ~9% for large messages. With the support from hardware
crypto i.e. the Intel AES-NI CPU instructions, the throughput increases
upto ~85% for small messages and ~55% for large messages.

By default, the new feature is inactive (i.e. no encryption) until user
sets a key for TIPC. There is however also a new option - "TIPC_CRYPTO"
in the kernel configuration to enable/disable the new code when needed.

MAINTAINERS | add two new files 'crypto.h' & 'crypto.c' in tipc

Acked-by: Ying Xue <ying.xue@windreiver.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Tuong Lien <tuong.t.lien@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

17 files changed, 2385 insertions, 46 deletions

diff --git a/net/tipc/Kconfig b/net/tipc/Kconfig
index b83e16ade4d2..716b61a701a8 100644
--- a/net/tipc/Kconfig
+++ b/net/tipc/Kconfig
@@ -35,6 +35,21 @@ config TIPC_MEDIA_UDP
 	  Saying Y here will enable support for running TIPC over IP/UDP
 	bool
 	default y
+config TIPC_CRYPTO
+	bool "TIPC encryption support"
+	depends on TIPC
+	select CRYPTO
+	select CRYPTO_AES
+	select CRYPTO_GCM
+	help
+	  Saying Y here will enable support for TIPC encryption.
+	  All TIPC messages will be encrypted/decrypted by using the currently most
+	  advanced algorithm: AEAD AES-GCM (like IPSec or TLS) before leaving/
+	  entering the TIPC stack.
+	  Key setting from user-space is performed via netlink by a user program
+	  (e.g. the iproute2 'tipc' tool).
+	bool
+	default y
 
 config TIPC_DIAG
 	tristate "TIPC: socket monitoring interface"
diff --git a/net/tipc/Makefile b/net/tipc/Makefile
index c86aba0282af..11255e970dd4 100644
--- a/net/tipc/Makefile
+++ b/net/tipc/Makefile
@@ -16,6 +16,7 @@ CFLAGS_trace.o += -I$(src)
 tipc-$(CONFIG_TIPC_MEDIA_UDP)	+= udp_media.o
 tipc-$(CONFIG_TIPC_MEDIA_IB)	+= ib_media.o
 tipc-$(CONFIG_SYSCTL)		+= sysctl.o
+tipc-$(CONFIG_TIPC_CRYPTO)	+= crypto.o
 
 
 obj-$(CONFIG_TIPC_DIAG)	+= diag.o
diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 6ef1abdd525f..f41096a759fa 100644
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -84,7 +84,7 @@ static struct tipc_bc_base *tipc_bc_base(struct net *net)
  */
 int tipc_bcast_get_mtu(struct net *net)
 {
-	return tipc_link_mtu(tipc_bc_sndlink(net)) - INT_H_SIZE;
+	return tipc_link_mss(tipc_bc_sndlink(net));
 }
 
 void tipc_bcast_disable_rcast(struct net *net)
diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index 6e15b9b1f1ef..d7ec26bd739d 100644
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -44,6 +44,7 @@
 #include "netlink.h"
 #include "udp_media.h"
 #include "trace.h"
+#include "crypto.h"
 
 #define MAX_ADDR_STR 60
 
@@ -516,10 +517,15 @@ void tipc_bearer_xmit_skb(struct net *net, u32 bearer_id,
 
 	rcu_read_lock();
 	b = bearer_get(net, bearer_id);
-	if (likely(b && (test_bit(0, &b->up) || msg_is_reset(hdr))))
-		b->media->send_msg(net, skb, b, dest);
-	else
+	if (likely(b && (test_bit(0, &b->up) || msg_is_reset(hdr)))) {
+#ifdef CONFIG_TIPC_CRYPTO
+		tipc_crypto_xmit(net, &skb, b, dest, NULL);
+		if (skb)
+#endif
+			b->media->send_msg(net, skb, b, dest);
+	} else {
 		kfree_skb(skb);
+	}
 	rcu_read_unlock();
 }
 
@@ -527,7 +533,8 @@ void tipc_bearer_xmit_skb(struct net *net, u32 bearer_id,
  */
 void tipc_bearer_xmit(struct net *net, u32 bearer_id,
 		      struct sk_buff_head *xmitq,
-		      struct tipc_media_addr *dst)
+		      struct tipc_media_addr *dst,
+		      struct tipc_node *__dnode)
 {
 	struct tipc_bearer *b;
 	struct sk_buff *skb, *tmp;
@@ -541,10 +548,15 @@ void tipc_bearer_xmit(struct net *net, u32 bearer_id,
 		__skb_queue_purge(xmitq);
 	skb_queue_walk_safe(xmitq, skb, tmp) {
 		__skb_dequeue(xmitq);
-		if (likely(test_bit(0, &b->up) || msg_is_reset(buf_msg(skb))))
-			b->media->send_msg(net, skb, b, dst);
-		else
+		if (likely(test_bit(0, &b->up) || msg_is_reset(buf_msg(skb)))) {
+#ifdef CONFIG_TIPC_CRYPTO
+			tipc_crypto_xmit(net, &skb, b, dst, __dnode);
+			if (skb)
+#endif
+				b->media->send_msg(net, skb, b, dst);
+		} else {
 			kfree_skb(skb);
+		}
 	}
 	rcu_read_unlock();
 }
@@ -555,6 +567,7 @@ void tipc_bearer_bc_xmit(struct net *net, u32 bearer_id,
 			 struct sk_buff_head *xmitq)
 {
 	struct tipc_net *tn = tipc_net(net);
+	struct tipc_media_addr *dst;
 	int net_id = tn->net_id;
 	struct tipc_bearer *b;
 	struct sk_buff *skb, *tmp;
@@ -569,7 +582,12 @@ void tipc_bearer_bc_xmit(struct net *net, u32 bearer_id,
 		msg_set_non_seq(hdr, 1);
 		msg_set_mc_netid(hdr, net_id);
 		__skb_dequeue(xmitq);
-		b->media->send_msg(net, skb, b, &b->bcast_addr);
+		dst = &b->bcast_addr;
+#ifdef CONFIG_TIPC_CRYPTO
+		tipc_crypto_xmit(net, &skb, b, dst, NULL);
+		if (skb)
+#endif
+			b->media->send_msg(net, skb, b, dst);
 	}
 	rcu_read_unlock();
 }
@@ -596,6 +614,7 @@ static int tipc_l2_rcv_msg(struct sk_buff *skb, struct net_device *dev,
 	if (likely(b && test_bit(0, &b->up) &&
 		   (skb->pkt_type <= PACKET_MULTICAST))) {
 		skb_mark_not_on_list(skb);
+		TIPC_SKB_CB(skb)->flags = 0;
 		tipc_rcv(dev_net(b->pt.dev), skb, b);
 		rcu_read_unlock();
 		return NET_RX_SUCCESS;
diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h
index faca696d422f..d0c79cc6c0c2 100644
--- a/net/tipc/bearer.h
+++ b/net/tipc/bearer.h
@@ -232,7 +232,8 @@ void tipc_bearer_xmit_skb(struct net *net, u32 bearer_id,
 			  struct tipc_media_addr *dest);
 void tipc_bearer_xmit(struct net *net, u32 bearer_id,
 		      struct sk_buff_head *xmitq,
-		      struct tipc_media_addr *dst);
+		      struct tipc_media_addr *dst,
+		      struct tipc_node *__dnode);
 void tipc_bearer_bc_xmit(struct net *net, u32 bearer_id,
 			 struct sk_buff_head *xmitq);
 void tipc_clone_to_loopback(struct net *net, struct sk_buff_head *pkts);
diff --git a/net/tipc/core.c b/net/tipc/core.c
index ab648dd150ee..fc01a13d7462 100644
--- a/net/tipc/core.c
+++ b/net/tipc/core.c
@@ -44,6 +44,7 @@
 #include "socket.h"
 #include "bcast.h"
 #include "node.h"
+#include "crypto.h"
 
 #include <linux/module.h>
 
@@ -68,6 +69,11 @@ static int __net_init tipc_init_net(struct net *net)
 	INIT_LIST_HEAD(&tn->node_list);
 	spin_lock_init(&tn->node_list_lock);
 
+#ifdef CONFIG_TIPC_CRYPTO
+	err = tipc_crypto_start(&tn->crypto_tx, net, NULL);
+	if (err)
+		goto out_crypto;
+#endif
 	err = tipc_sk_rht_init(net);
 	if (err)
 		goto out_sk_rht;
@@ -93,6 +99,11 @@ out_bclink:
 out_nametbl:
 	tipc_sk_rht_destroy(net);
 out_sk_rht:
+
+#ifdef CONFIG_TIPC_CRYPTO
+	tipc_crypto_stop(&tn->crypto_tx);
+out_crypto:
+#endif
 	return err;
 }
 
@@ -103,6 +114,9 @@ static void __net_exit tipc_exit_net(struct net *net)
 	tipc_bcast_stop(net);
 	tipc_nametbl_stop(net);
 	tipc_sk_rht_destroy(net);
+#ifdef CONFIG_TIPC_CRYPTO
+	tipc_crypto_stop(&tipc_net(net)->crypto_tx);
+#endif
 }
 
 static void __net_exit tipc_pernet_pre_exit(struct net *net)
diff --git a/net/tipc/core.h b/net/tipc/core.h
index 8776d32a4a47..775848a5f27e 100644
--- a/net/tipc/core.h
+++ b/net/tipc/core.h
@@ -68,6 +68,9 @@ struct tipc_link;
 struct tipc_name_table;
 struct tipc_topsrv;
 struct tipc_monitor;
+#ifdef CONFIG_TIPC_CRYPTO
+struct tipc_crypto;
+#endif
 
 #define TIPC_MOD_VER "2.0.0"
 
@@ -129,6 +132,11 @@ struct tipc_net {
 
 	/* Tracing of node internal messages */
 	struct packet_type loopback_pt;
+
+#ifdef CONFIG_TIPC_CRYPTO
+	/* TX crypto handler */
+	struct tipc_crypto *crypto_tx;
+#endif
 };
 
 static inline struct tipc_net *tipc_net(struct net *net)
diff --git a/net/tipc/crypto.c b/net/tipc/crypto.c
new file mode 100644
index 000000000000..05f7ca76e8ce
--- /dev/null
+++ b/net/tipc/crypto.c
@@ -0,0 +1,1986 @@
+// SPDX-License-Identifier: GPL-2.0
+/**
+ * net/tipc/crypto.c: TIPC crypto for key handling & packet en/decryption
+ *
+ * Copyright (c) 2019, Ericsson AB
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <crypto/aead.h>
+#include <crypto/aes.h>
+#include "crypto.h"
+
+#define TIPC_TX_PROBE_LIM	msecs_to_jiffies(1000) /* > 1s */
+#define TIPC_TX_LASTING_LIM	msecs_to_jiffies(120000) /* 2 mins */
+#define TIPC_RX_ACTIVE_LIM	msecs_to_jiffies(3000) /* 3s */
+#define TIPC_RX_PASSIVE_LIM	msecs_to_jiffies(180000) /* 3 mins */
+#define TIPC_MAX_TFMS_DEF	10
+#define TIPC_MAX_TFMS_LIM	1000
+
+/**
+ * TIPC Key ids
+ */
+enum {
+	KEY_UNUSED = 0,
+	KEY_MIN,
+	KEY_1 = KEY_MIN,
+	KEY_2,
+	KEY_3,
+	KEY_MAX = KEY_3,
+};
+
+/**
+ * TIPC Crypto statistics
+ */
+enum {
+	STAT_OK,
+	STAT_NOK,
+	STAT_ASYNC,
+	STAT_ASYNC_OK,
+	STAT_ASYNC_NOK,
+	STAT_BADKEYS, /* tx only */
+	STAT_BADMSGS = STAT_BADKEYS, /* rx only */
+	STAT_NOKEYS,
+	STAT_SWITCHES,
+
+	MAX_STATS,
+};
+
+/* TIPC crypto statistics' header */
+static const char *hstats[MAX_STATS] = {"ok", "nok", "async", "async_ok",
+					"async_nok", "badmsgs", "nokeys",
+					"switches"};
+
+/* Max TFMs number per key */
+int sysctl_tipc_max_tfms __read_mostly = TIPC_MAX_TFMS_DEF;
+
+/**
+ * struct tipc_key - TIPC keys' status indicator
+ *
+ *         7     6     5     4     3     2     1     0
+ *      +-----+-----+-----+-----+-----+-----+-----+-----+
+ * key: | (reserved)|passive idx| active idx|pending idx|
+ *      +-----+-----+-----+-----+-----+-----+-----+-----+
+ */
+struct tipc_key {
+#define KEY_BITS (2)
+#define KEY_MASK ((1 << KEY_BITS) - 1)
+	union {
+		struct {
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+			u8 pending:2,
+			   active:2,
+			   passive:2, /* rx only */
+			   reserved:2;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+			u8 reserved:2,
+			   passive:2, /* rx only */
+			   active:2,
+			   pending:2;
+#else
+#error  "Please fix <asm/byteorder.h>"
+#endif
+		} __packed;
+		u8 keys;
+	};
+};
+
+/**
+ * struct tipc_tfm - TIPC TFM structure to form a list of TFMs
+ */
+struct tipc_tfm {
+	struct crypto_aead *tfm;
+	struct list_head list;
+};
+
+/**
+ * struct tipc_aead - TIPC AEAD key structure
+ * @tfm_entry: per-cpu pointer to one entry in TFM list
+ * @crypto: TIPC crypto owns this key
+ * @cloned: reference to the source key in case cloning
+ * @users: the number of the key users (TX/RX)
+ * @salt: the key's SALT value
+ * @authsize: authentication tag size (max = 16)
+ * @mode: crypto mode is applied to the key
+ * @hint[]: a hint for user key
+ * @rcu: struct rcu_head
+ * @seqno: the key seqno (cluster scope)
+ * @refcnt: the key reference counter
+ */
+struct tipc_aead {
+#define TIPC_AEAD_HINT_LEN (5)
+	struct tipc_tfm * __percpu *tfm_entry;
+	struct tipc_crypto *crypto;
+	struct tipc_aead *cloned;
+	atomic_t users;
+	u32 salt;
+	u8 authsize;
+	u8 mode;
+	char hint[TIPC_AEAD_HINT_LEN + 1];
+	struct rcu_head rcu;
+
+	atomic64_t seqno ____cacheline_aligned;
+	refcount_t refcnt ____cacheline_aligned;
+
+} ____cacheline_aligned;
+
+/**
+ * struct tipc_crypto_stats - TIPC Crypto statistics
+ */
+struct tipc_crypto_stats {
+	unsigned int stat[MAX_STATS];
+};
+
+/**
+ * struct tipc_crypto - TIPC TX/RX crypto structure
+ * @net: struct net
+ * @node: TIPC node (RX)
+ * @aead: array of pointers to AEAD keys for encryption/decryption
+ * @peer_rx_active: replicated peer RX active key index
+ * @key: the key states
+ * @working: the crypto is working or not
+ * @stats: the crypto statistics
+ * @sndnxt: the per-peer sndnxt (TX)
+ * @timer1: general timer 1 (jiffies)
+ * @timer2: general timer 1 (jiffies)
+ * @lock: tipc_key lock
+ */
+struct tipc_crypto {
+	struct net *net;
+	struct tipc_node *node;
+	struct tipc_aead __rcu *aead[KEY_MAX + 1]; /* key[0] is UNUSED */
+	atomic_t peer_rx_active;
+	struct tipc_key key;
+	u8 working:1;
+	struct tipc_crypto_stats __percpu *stats;
+
+	atomic64_t sndnxt ____cacheline_aligned;
+	unsigned long timer1;
+	unsigned long timer2;
+	spinlock_t lock; /* crypto lock */
+
+} ____cacheline_aligned;
+
+/* struct tipc_crypto_tx_ctx - TX context for callbacks */
+struct tipc_crypto_tx_ctx {
+	struct tipc_aead *aead;
+	struct tipc_bearer *bearer;
+	struct tipc_media_addr dst;
+};
+
+/* struct tipc_crypto_rx_ctx - RX context for callbacks */
+struct tipc_crypto_rx_ctx {
+	struct tipc_aead *aead;
+	struct tipc_bearer *bearer;
+};
+
+static struct tipc_aead *tipc_aead_get(struct tipc_aead __rcu *aead);
+static inline void tipc_aead_put(struct tipc_aead *aead);
+static void tipc_aead_free(struct rcu_head *rp);
+static int tipc_aead_users(struct tipc_aead __rcu *aead);
+static void tipc_aead_users_inc(struct tipc_aead __rcu *aead, int lim);
+static void tipc_aead_users_dec(struct tipc_aead __rcu *aead, int lim);
+static void tipc_aead_users_set(struct tipc_aead __rcu *aead, int val);
+static struct crypto_aead *tipc_aead_tfm_next(struct tipc_aead *aead);
+static int tipc_aead_init(struct tipc_aead **aead, struct tipc_aead_key *ukey,
+			  u8 mode);
+static int tipc_aead_clone(struct tipc_aead **dst, struct tipc_aead *src);
+static void *tipc_aead_mem_alloc(struct crypto_aead *tfm,
+				 unsigned int crypto_ctx_size,
+				 u8 **iv, struct aead_request **req,
+				 struct scatterlist **sg, int nsg);
+static int tipc_aead_encrypt(struct tipc_aead *aead, struct sk_buff *skb,
+			     struct tipc_bearer *b,
+			     struct tipc_media_addr *dst,
+			     struct tipc_node *__dnode);
+static void tipc_aead_encrypt_done(struct crypto_async_request *base, int err);
+static int tipc_aead_decrypt(struct net *net, struct tipc_aead *aead,
+			     struct sk_buff *skb, struct tipc_bearer *b);
+static void tipc_aead_decrypt_done(struct crypto_async_request *base, int err);
+static inline int tipc_ehdr_size(struct tipc_ehdr *ehdr);
+static int tipc_ehdr_build(struct net *net, struct tipc_aead *aead,
+			   u8 tx_key, struct sk_buff *skb,
+			   struct tipc_crypto *__rx);
+static inline void tipc_crypto_key_set_state(struct tipc_crypto *c,
+					     u8 new_passive,
+					     u8 new_active,
+					     u8 new_pending);
+static int tipc_crypto_key_attach(struct tipc_crypto *c,
+				  struct tipc_aead *aead, u8 pos);
+static bool tipc_crypto_key_try_align(struct tipc_crypto *rx, u8 new_pending);
+static struct tipc_aead *tipc_crypto_key_pick_tx(struct tipc_crypto *tx,
+						 struct tipc_crypto *rx,
+						 struct sk_buff *skb);
+static void tipc_crypto_key_synch(struct tipc_crypto *rx, u8 new_rx_active,
+				  struct tipc_msg *hdr);
+static int tipc_crypto_key_revoke(struct net *net, u8 tx_key);
+static void tipc_crypto_rcv_complete(struct net *net, struct tipc_aead *aead,
+				     struct tipc_bearer *b,
+				     struct sk_buff **skb, int err);
+static void tipc_crypto_do_cmd(struct net *net, int cmd);
+static char *tipc_crypto_key_dump(struct tipc_crypto *c, char *buf);
+#ifdef TIPC_CRYPTO_DEBUG
+static char *tipc_key_change_dump(struct tipc_key old, struct tipc_key new,
+				  char *buf);
+#endif
+
+#define key_next(cur) ((cur) % KEY_MAX + 1)
+
+#define tipc_aead_rcu_ptr(rcu_ptr, lock)				\
+	rcu_dereference_protected((rcu_ptr), lockdep_is_held(lock))
+
+#define tipc_aead_rcu_swap(rcu_ptr, ptr, lock)				\
+	rcu_swap_protected((rcu_ptr), (ptr), lockdep_is_held(lock))
+
+#define tipc_aead_rcu_replace(rcu_ptr, ptr, lock)			\
+do {									\
+	typeof(rcu_ptr) __tmp = rcu_dereference_protected((rcu_ptr),	\
+						lockdep_is_held(lock));	\
+	rcu_assign_pointer((rcu_ptr), (ptr));				\
+	tipc_aead_put(__tmp);						\
+} while (0)
+
+#define tipc_crypto_key_detach(rcu_ptr, lock)				\
+	tipc_aead_rcu_replace((rcu_ptr), NULL, lock)
+
+/**
+ * tipc_aead_key_validate - Validate a AEAD user key
+ */
+int tipc_aead_key_validate(struct tipc_aead_key *ukey)
+{
+	int keylen;
+
+	/* Check if algorithm exists */
+	if (unlikely(!crypto_has_alg(ukey->alg_name, 0, 0))) {
+		pr_info("Not found cipher: \"%s\"!\n", ukey->alg_name);
+		return -ENODEV;
+	}
+
+	/* Currently, we only support the "gcm(aes)" cipher algorithm */
+	if (strcmp(ukey->alg_name, "gcm(aes)"))
+		return -ENOTSUPP;
+
+	/* Check if key size is correct */
+	keylen = ukey->keylen - TIPC_AES_GCM_SALT_SIZE;
+	if (unlikely(keylen != TIPC_AES_GCM_KEY_SIZE_128 &&
+		     keylen != TIPC_AES_GCM_KEY_SIZE_192 &&
+		     keylen != TIPC_AES_GCM_KEY_SIZE_256))
+		return -EINVAL;
+
+	return 0;
+}
+
+static struct tipc_aead *tipc_aead_get(struct tipc_aead __rcu *aead)
+{
+	struct tipc_aead *tmp;
+
+	rcu_read_lock();
+	tmp = rcu_dereference(aead);
+	if (unlikely(!tmp || !refcount_inc_not_zero(&tmp->refcnt)))
+		tmp = NULL;
+	rcu_read_unlock();
+
+	return tmp;
+}
+
+static inline void tipc_aead_put(struct tipc_aead *aead)
+{
+	if (aead && refcount_dec_and_test(&aead->refcnt))
+		call_rcu(&aead->rcu, tipc_aead_free);
+}
+
+/**
+ * tipc_aead_free - Release AEAD key incl. all the TFMs in the list
+ * @rp: rcu head pointer
+ */
+static void tipc_aead_free(struct rcu_head *rp)
+{
+	struct tipc_aead *aead = container_of(rp, struct tipc_aead, rcu);
+	struct tipc_tfm *tfm_entry, *head, *tmp;
+
+	if (aead->cloned) {
+		tipc_aead_put(aead->cloned);
+	} else {
+		head = *this_cpu_ptr(aead->tfm_entry);
+		list_for_each_entry_safe(tfm_entry, tmp, &head->list, list) {
+			crypto_free_aead(tfm_entry->tfm);
+			list_del(&tfm_entry->list);
+			kfree(tfm_entry);
+		}
+		/* Free the head */
+		crypto_free_aead(head->tfm);
+		list_del(&head->list);
+		kfree(head);
+	}
+	free_percpu(aead->tfm_entry);
+	kfree(aead);
+}
+
+static int tipc_aead_users(struct tipc_aead __rcu *aead)
+{
+	struct tipc_aead *tmp;
+	int users = 0;
+
+	rcu_read_lock();
+	tmp = rcu_dereference(aead);
+	if (tmp)
+		users = atomic_read(&tmp->users);
+	rcu_read_unlock();
+
+	return users;
+}
+
+static void tipc_aead_users_inc(struct tipc_aead __rcu *aead, int lim)
+{
+	struct tipc_aead *tmp;
+
+	rcu_read_lock();
+	tmp = rcu_dereference(aead);
+	if (tmp)
+		atomic_add_unless(&tmp->users, 1, lim);
+	rcu_read_unlock();
+}
+
+static void tipc_aead_users_dec(struct tipc_aead __rcu *aead, int lim)
+{
+	struct tipc_aead *tmp;
+
+	rcu_read_lock();
+	tmp = rcu_dereference(aead);
+	if (tmp)
+		atomic_add_unless(&rcu_dereference(aead)->users, -1, lim);
+	rcu_read_unlock();
+}
+
+static void tipc_aead_users_set(struct tipc_aead __rcu *aead, int val)
+{
+	struct tipc_aead *tmp;
+	int cur;
+
+	rcu_read_lock();
+	tmp = rcu_dereference(aead);
+	if (tmp) {
+		do {
+			cur = atomic_read(&tmp->users);
+			if (cur == val)
+				break;
+		} while (atomic_cmpxchg(&tmp->users, cur, val) != cur);
+	}
+	rcu_read_unlock();
+}
+
+/**
+ * tipc_aead_tfm_next - Move TFM entry to the next one in list and return it
+ */
+static struct crypto_aead *tipc_aead_tfm_next(struct tipc_aead *aead)
+{
+	struct tipc_tfm **tfm_entry = this_cpu_ptr(aead->tfm_entry);
+
+	*tfm_entry = list_next_entry(*tfm_entry, list);
+	return (*tfm_entry)->tfm;
+}
+
+/**
+ * tipc_aead_init - Initiate TIPC AEAD
+ * @aead: returned new TIPC AEAD key handle pointer
+ * @ukey: pointer to user key data
+ * @mode: the key mode
+ *
+ * Allocate a (list of) new cipher transformation (TFM) with the specific user
+ * key data if valid. The number of the allocated TFMs can be set via the sysfs
+ * "net/tipc/max_tfms" first.
+ * Also, all the other AEAD data are also initialized.
+ *
+ * Return: 0 if the initiation is successful, otherwise: < 0
+ */
+static int tipc_aead_init(struct tipc_aead **aead, struct tipc_aead_key *ukey,
+			  u8 mode)
+{
+	struct tipc_tfm *tfm_entry, *head;
+	struct crypto_aead *tfm;
+	struct tipc_aead *tmp;
+	int keylen, err, cpu;
+	int tfm_cnt = 0;
+
+	if (unlikely(*aead))
+		return -EEXIST;
+
+	/* Allocate a new AEAD */
+	tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC);
+	if (unlikely(!tmp))
+		return -ENOMEM;
+
+	/* The key consists of two parts: [AES-KEY][SALT] */
+	keylen = ukey->keylen - TIPC_AES_GCM_SALT_SIZE;
+
+	/* Allocate per-cpu TFM entry pointer */
+	tmp->tfm_entry = alloc_percpu(struct tipc_tfm *);
+	if (!tmp->tfm_entry) {
+		kzfree(tmp);
+		return -ENOMEM;
+	}
+
+	/* Make a list of TFMs with the user key data */
+	do {
+		tfm = crypto_alloc_aead(ukey->alg_name, 0, 0);
+		if (IS_ERR(tfm)) {
+			err = PTR_ERR(tfm);
+			break;
+		}
+
+		if (unlikely(!tfm_cnt &&
+			     crypto_aead_ivsize(tfm) != TIPC_AES_GCM_IV_SIZE)) {
+			crypto_free_aead(tfm);
+			err = -ENOTSUPP;
+			break;
+		}
+
+		err |= crypto_aead_setauthsize(tfm, TIPC_AES_GCM_TAG_SIZE);
+		err |= crypto_aead_setkey(tfm, ukey->key, keylen);
+		if (unlikely(err)) {
+			crypto_free_aead(tfm);
+			break;
+		}
+
+		tfm_entry = kmalloc(sizeof(*tfm_entry), GFP_KERNEL);
+		if (unlikely(!tfm_entry)) {
+			crypto_free_aead(tfm);
+			err = -ENOMEM;
+			break;
+		}
+		INIT_LIST_HEAD(&tfm_entry->list);
+		tfm_entry->tfm = tfm;
+
+		/* First entry? */
+		if (!tfm_cnt) {
+			head = tfm_entry;
+			for_each_possible_cpu(cpu) {
+				*per_cpu_ptr(tmp->tfm_entry, cpu) = head;
+			}
+		} else {
+			list_add_tail(&tfm_entry->list, &head->list);
+		}
+
+	} while (++tfm_cnt < sysctl_tipc_max_tfms);
+
+	/* Not any TFM is allocated? */
+	if (!tfm_cnt) {
+		free_percpu(tmp->tfm_entry);
+		kzfree(tmp);
+		return err;
+	}
+
+	/* Copy some chars from the user key as a hint */
+	memcpy(tmp->hint, ukey->key, TIPC_AEAD_HINT_LEN);
+	tmp->hint[TIPC_AEAD_HINT_LEN] = '\0';
+
+	/* Initialize the other data */
+	tmp->mode = mode;
+	tmp->cloned = NULL;
+	tmp->authsize = TIPC_AES_GCM_TAG_SIZE;
+	memcpy(&tmp->salt, ukey->key + keylen, TIPC_AES_GCM_SALT_SIZE);
+	atomic_set(&tmp->users, 0);
+	atomic64_set(&tmp->seqno, 0);
+	refcount_set(&tmp->refcnt, 1);
+
+	*aead = tmp;
+	return 0;
+}
+
+/**
+ * tipc_aead_clone - Clone a TIPC AEAD key
+ * @dst: dest key for the cloning
+ * @src: source key to clone from
+ *
+ * Make a "copy" of the source AEAD key data to the dest, the TFMs list is
+ * common for the keys.
+ * A reference to the source is hold in the "cloned" pointer for the later
+ * freeing purposes.
+ *
+ * Note: this must be done in cluster-key mode only!
+ * Return: 0 in case of success, otherwise < 0
+ */
+static int tipc_aead_clone(struct tipc_aead **dst, struct tipc_aead *src)
+{
+	struct tipc_aead *aead;
+	int cpu;
+
+	if (!src)
+		return -ENOKEY;
+
+	if (src->mode != CLUSTER_KEY)
+		return -EINVAL;
+
+	if (unlikely(*dst))
+		return -EEXIST;
+
+	aead = kzalloc(sizeof(*aead), GFP_ATOMIC);
+	if (unlikely(!aead))
+		return -ENOMEM;
+
+	aead->tfm_entry = alloc_percpu_gfp(struct tipc_tfm *, GFP_ATOMIC);
+	if (unlikely(!aead->tfm_entry)) {
+		kzfree(aead);
+		return -ENOMEM;
+	}
+
+	for_each_possible_cpu(cpu) {
+		*per_cpu_ptr(aead->tfm_entry, cpu) =
+				*per_cpu_ptr(src->tfm_entry, cpu);
+	}
+
+	memcpy(aead->hint, src->hint, sizeof(src->hint));
+	aead->mode = src->mode;
+	aead->salt = src->salt;
+	aead->authsize = src->authsize;
+	atomic_set(&aead->users, 0);
+	atomic64_set(&aead->seqno, 0);
+	refcount_set(&aead->refcnt, 1);
+
+	WARN_ON(!refcount_inc_not_zero(&src->refcnt));
+	aead->cloned = src;
+
+	*dst = aead;
+	return 0;
+}
+
+/**
+ * tipc_aead_mem_alloc - Allocate memory for AEAD request operations
+ * @tfm: cipher handle to be registered with the request
+ * @crypto_ctx_size: size of crypto context for callback
+ * @iv: returned pointer to IV data
+ * @req: returned pointer to AEAD request data
+ * @sg: returned pointer to SG lists
+ * @nsg: number of SG lists to be allocated
+ *
+ * Allocate memory to store the crypto context data, AEAD request, IV and SG
+ * lists, the memory layout is as follows:
+ * crypto_ctx || iv || aead_req || sg[]
+ *
+ * Return: the pointer to the memory areas in case of success, otherwise NULL
+ */
+static void *tipc_aead_mem_alloc(struct crypto_aead *tfm,
+				 unsigned int crypto_ctx_size,
+				 u8 **iv, struct aead_request **req,
+				 struct scatterlist **sg, int nsg)
+{
+	unsigned int iv_size, req_size;
+	unsigned int len;
+	u8 *mem;
+
+	iv_size = crypto_aead_ivsize(tfm);
+	req_size = sizeof(**req) + crypto_aead_reqsize(tfm);
+
+	len = crypto_ctx_size;
+	len += iv_size;
+	len += crypto_aead_alignmask(tfm) & ~(crypto_tfm_ctx_alignment() - 1);
+	len = ALIGN(len, crypto_tfm_ctx_alignment());
+	len += req_size;
+	len = ALIGN(len, __alignof__(struct scatterlist));
+	len += nsg * sizeof(**sg);
+
+	mem = kmalloc(len, GFP_ATOMIC);
+	if (!mem)
+		return NULL;
+
+	*iv = (u8 *)PTR_ALIGN(mem + crypto_ctx_size,
+			      crypto_aead_alignmask(tfm) + 1);
+	*req = (struct aead_request *)PTR_ALIGN(*iv + iv_size,
+						crypto_tfm_ctx_alignment());
+	*sg = (struct scatterlist *)PTR_ALIGN((u8 *)*req + req_size,
+					      __alignof__(struct scatterlist));
+
+	return (void *)mem;
+}
+
+/**
+ * tipc_aead_encrypt - Encrypt a message
+ * @aead: TIPC AEAD key for the message encryption
+ * @skb: the input/output skb
+ * @b: TIPC bearer where the message will be delivered after the encryption
+ * @dst: the destination media address
+ * @__dnode: TIPC dest node if "known"
+ *
+ * Return:
+ * 0                   : if the encryption has completed
+ * -EINPROGRESS/-EBUSY : if a callback will be performed
+ * < 0                 : the encryption has failed
+ */
+static int tipc_aead_encrypt(struct tipc_aead *aead, struct sk_buff *skb,
+			     struct tipc_bearer *b,
+			     struct tipc_media_addr *dst,
+			     struct tipc_node *__dnode)
+{
+	struct crypto_aead *tfm = tipc_aead_tfm_next(aead);
+	struct tipc_crypto_tx_ctx *tx_ctx;
+	struct aead_request *req;
+	struct sk_buff *trailer;
+	struct scatterlist *sg;
+	struct tipc_ehdr *ehdr;
+	int ehsz, len, tailen, nsg, rc;
+	void *ctx;
+	u32 salt;
+	u8 *iv;
+
+	/* Make sure message len at least 4-byte aligned */
+	len = ALIGN(skb->len, 4);
+	tailen = len - skb->len + aead->authsize;
+
+	/* Expand skb tail for authentication tag:
+	 * As for simplicity, we'd have made sure skb having enough tailroom
+	 * for authentication tag @skb allocation. Even when skb is nonlinear
+	 * but there is no frag_list, it should be still fine!
+	 * Otherwise, we must cow it to be a writable buffer with the tailroom.
+	 */
+#ifdef TIPC_CRYPTO_DEBUG
+	SKB_LINEAR_ASSERT(skb);
+	if (tailen > skb_tailroom(skb)) {
+		pr_warn("TX: skb tailroom is not enough: %d, requires: %d\n",
+			skb_tailroom(skb), tailen);
+	}
+#endif
+
+	if (unlikely(!skb_cloned(skb) && tailen <= skb_tailroom(skb))) {
+		nsg = 1;
+		trailer = skb;
+	} else {
+		/* TODO: We could avoid skb_cow_data() if skb has no frag_list
+		 * e.g. by skb_fill_page_desc() to add another page to the skb
+		 * with the wanted tailen... However, page skbs look not often,
+		 * so take it easy now!
+		 * Cloned skbs e.g. from link_xmit() seems no choice though :(
+		 */
+		nsg = skb_cow_data(skb, tailen, &trailer);
+		if (unlikely(nsg < 0)) {
+			pr_err("TX: skb_cow_data() returned %d\n", nsg);
+			return nsg;
+		}
+	}
+
+	pskb_put(skb, trailer, tailen);
+
+	/* Allocate memory for the AEAD operation */
+	ctx = tipc_aead_mem_alloc(tfm, sizeof(*tx_ctx), &iv, &req, &sg, nsg);
+	if (unlikely(!ctx))
+		return -ENOMEM;
+	TIPC_SKB_CB(skb)->crypto_ctx = ctx;
+
+	/* Map skb to the sg lists */
+	sg_init_table(sg, nsg);
+	rc = skb_to_sgvec(skb, sg, 0, skb->len);
+	if (unlikely(rc < 0)) {
+		pr_err("TX: skb_to_sgvec() returned %d, nsg %d!\n", rc, nsg);
+		goto exit;
+	}
+
+	/* Prepare IV: [SALT (4 octets)][SEQNO (8 octets)]
+	 * In case we're in cluster-key mode, SALT is varied by xor-ing with
+	 * the source address (or w0 of id), otherwise with the dest address
+	 * if dest is known.
+	 */
+	ehdr = (struct tipc_ehdr *)skb->data;
+	salt = aead->salt;
+	if (aead->mode == CLUSTER_KEY)
+		salt ^= ehdr->addr; /* __be32 */
+	else if (__dnode)
+		salt ^= tipc_node_get_addr(__dnode);
+	memcpy(iv, &salt, 4);
+	memcpy(iv + 4, (u8 *)&ehdr->seqno, 8);
+
+	/* Prepare request */
+	ehsz = tipc_ehdr_size(ehdr);
+	aead_request_set_tfm(req, tfm);
+	aead_request_set_ad(req, ehsz);
+	aead_request_set_crypt(req, sg, sg, len - ehsz, iv);
+
+	/* Set callback function & data */
+	aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+				  tipc_aead_encrypt_done, skb);
+	tx_ctx = (struct tipc_crypto_tx_ctx *)ctx;
+	tx_ctx->aead = aead;
+	tx_ctx->bearer = b;
+	memcpy(&tx_ctx->dst, dst, sizeof(*dst));
+
+	/* Hold bearer */
+	if (unlikely(!tipc_bearer_hold(b))) {
+		rc = -ENODEV;
+		goto exit;
+	}
+
+	/* Now, do encrypt */
+	rc = crypto_aead_encrypt(req);
+	if (rc == -EINPROGRESS || rc == -EBUSY)
+		return rc;
+
+	tipc_bearer_put(b);
+
+exit:
+	kfree(ctx);
+	TIPC_SKB_CB(skb)->crypto_ctx = NULL;
+	return rc;
+}
+
+static void tipc_aead_encrypt_done(struct crypto_async_request *base, int err)
+{
+	struct sk_buff *skb = base->data;
+	struct tipc_crypto_tx_ctx *tx_ctx = TIPC_SKB_CB(skb)->crypto_ctx;
+	struct tipc_bearer *b = tx_ctx->bearer;
+	struct tipc_aead *aead = tx_ctx->aead;
+	struct tipc_crypto *tx = aead->crypto;
+	struct net *net = tx->net;
+
+	switch (err) {
+	case 0:
+		this_cpu_inc(tx->stats->stat[STAT_ASYNC_OK]);
+		if (likely(test_bit(0, &b->up)))
+			b->media->send_msg(net, skb, b, &tx_ctx->dst);
+		else
+			kfree_skb(skb);
+		break;
+	case -EINPROGRESS:
+		return;
+	default:
+		this_cpu_inc(tx->stats->stat[STAT_ASYNC_NOK]);
+		kfree_skb(skb);
+		break;
+	}
+
+	kfree(tx_ctx);
+	tipc_bearer_put(b);
+	tipc_aead_put(aead);
+}
+
+/**
+ * tipc_aead_decrypt - Decrypt an encrypted message
+ * @net: struct net
+ * @aead: TIPC AEAD for the message decryption
+ * @skb: the input/output skb
+ * @b: TIPC bearer where the message has been received
+ *
+ * Return:
+ * 0                   : if the decryption has completed
+ * -EINPROGRESS/-EBUSY : if a callback will be performed
+ * < 0                 : the decryption has failed
+ */
+static int tipc_aead_decrypt(struct net *net, struct tipc_aead *aead,
+			     struct sk_buff *skb, struct tipc_bearer *b)
+{
+	struct tipc_crypto_rx_ctx *rx_ctx;
+	struct aead_request *req;
+	struct crypto_aead *tfm;
+	struct sk_buff *unused;
+	struct scatterlist *sg;
+	struct tipc_ehdr *ehdr;
+	int ehsz, nsg, rc;
+	void *ctx;
+	u32 salt;
+	u8 *iv;
+
+	if (unlikely(!aead))
+		return -ENOKEY;
+
+	/* Cow skb data if needed */
+	if (likely(!skb_cloned(skb) &&
+		   (!skb_is_nonlinear(skb) || !skb_has_frag_list(skb)))) {
+		nsg = 1 + skb_shinfo(skb)->nr_frags;
+	} else {
+		nsg = skb_cow_data(skb, 0, &unused);
+		if (unlikely(nsg < 0)) {
+			pr_err("RX: skb_cow_data() returned %d\n", nsg);
+			return nsg;
+		}
+	}
+
+	/* Allocate memory for the AEAD operation */
+	tfm = tipc_aead_tfm_next(aead);
+	ctx = tipc_aead_mem_alloc(tfm, sizeof(*rx_ctx), &iv, &req, &sg, nsg);
+	if (unlikely(!ctx))
+		return -ENOMEM;
+	TIPC_SKB_CB(skb)->crypto_ctx = ctx;
+
+	/* Map skb to the sg lists */
+	sg_init_table(sg, nsg);
+	rc = skb_to_sgvec(skb, sg, 0, skb->len);
+	if (unlikely(rc < 0)) {
+		pr_err("RX: skb_to_sgvec() returned %d, nsg %d\n", rc, nsg);
+		goto exit;
+	}
+
+	/* Reconstruct IV: */
+	ehdr = (struct tipc_ehdr *)skb->data;
+	salt = aead->salt;
+	if (aead->mode == CLUSTER_KEY)
+		salt ^= ehdr->addr; /* __be32 */
+	else if (ehdr->destined)
+		salt ^= tipc_own_addr(net);
+	memcpy(iv, &salt, 4);
+	memcpy(iv + 4, (u8 *)&ehdr->seqno, 8);
+
+	/* Prepare request */
+	ehsz = tipc_ehdr_size(ehdr);
+	aead_request_set_tfm(req, tfm);
+	aead_request_set_ad(req, ehsz);
+	aead_request_set_crypt(req, sg, sg, skb->len - ehsz, iv);
+
+	/* Set callback function & data */
+	aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+				  tipc_aead_decrypt_done, skb);
+	rx_ctx = (struct tipc_crypto_rx_ctx *)ctx;
+	rx_ctx->aead = aead;
+	rx_ctx->bearer = b;
+
+	/* Hold bearer */
+	if (unlikely(!tipc_bearer_hold(b))) {
+		rc = -ENODEV;
+		goto exit;
+	}
+
+	/* Now, do decrypt */
+	rc = crypto_aead_decrypt(req);
+	if (rc == -EINPROGRESS || rc == -EBUSY)
+		return rc;
+
+	tipc_bearer_put(b);
+
+exit:
+	kfree(ctx);
+	TIPC_SKB_CB(skb)->crypto_ctx = NULL;
+	return rc;
+}
+
+static void tipc_aead_decrypt_done(struct crypto_async_request *base, int err)
+{
+	struct sk_buff *skb = base->data;
+	struct tipc_crypto_rx_ctx *rx_ctx = TIPC_SKB_CB(skb)->crypto_ctx;
+	struct tipc_bearer *b = rx_ctx->bearer;
+	struct tipc_aead *aead = rx_ctx->aead;
+	struct tipc_crypto_stats __percpu *stats = aead->crypto->stats;
+	struct net *net = aead->crypto->net;
+
+	switch (err) {
+	case 0:
+		this_cpu_inc(stats->stat[STAT_ASYNC_OK]);
+		break;
+	case -EINPROGRESS:
+		return;
+	default:
+		this_cpu_inc(stats->stat[STAT_ASYNC_NOK]);
+		break;
+	}
+
+	kfree(rx_ctx);
+	tipc_crypto_rcv_complete(net, aead, b, &skb, err);
+	if (likely(skb)) {
+		if (likely(test_bit(0, &b->up)))
+			tipc_rcv(net, skb, b);
+		else
+			kfree_skb(skb);
+	}
+
+	tipc_bearer_put(b);
+}
+
+static inline int tipc_ehdr_size(struct tipc_ehdr *ehdr)
+{
+	return (ehdr->user != LINK_CONFIG) ? EHDR_SIZE : EHDR_CFG_SIZE;
+}
+
+/**
+ * tipc_ehdr_validate - Validate an encryption message
+ * @skb: the message buffer
+ *
+ * Returns "true" if this is a valid encryption message, otherwise "false"
+ */
+bool tipc_ehdr_validate(struct sk_buff *skb)
+{
+	struct tipc_ehdr *ehdr;
+	int ehsz;
+
+	if (unlikely(!pskb_may_pull(skb, EHDR_MIN_SIZE)))
+		return false;
+
+	ehdr = (struct tipc_ehdr *)skb->data;
+	if (unlikely(ehdr->version != TIPC_EVERSION))
+		return false;
+	ehsz = tipc_ehdr_size(ehdr);
+	if (unlikely(!pskb_may_pull(skb, ehsz)))
+		return false;
+	if (unlikely(skb->len <= ehsz + TIPC_AES_GCM_TAG_SIZE))
+		return false;
+	if (unlikely(!ehdr->tx_key))
+		return false;
+
+	return true;
+}
+
+/**
+ * tipc_ehdr_build - Build TIPC encryption message header
+ * @net: struct net
+ * @aead: TX AEAD key to be used for the message encryption
+ * @tx_key: key id used for the message encryption
+ * @skb: input/output message skb
+ * @__rx: RX crypto handle if dest is "known"
+ *
+ * Return: the header size if the building is successful, otherwise < 0
+ */
+static int tipc_ehdr_build(struct net *net, struct tipc_aead *aead,
+			   u8 tx_key, struct sk_buff *skb,
+			   struct tipc_crypto *__rx)
+{
+	struct tipc_msg *hdr = buf_msg(skb);
+	struct tipc_ehdr *ehdr;
+	u32 user = msg_user(hdr);
+	u64 seqno;
+	int ehsz;
+
+	/* Make room for encryption header */
+	ehsz = (user != LINK_CONFIG) ? EHDR_SIZE : EHDR_CFG_SIZE;
+	WARN_ON(skb_headroom(skb) < ehsz);
+	ehdr = (struct tipc_ehdr *)skb_push(skb, ehsz);
+
+	/* Obtain a seqno first:
+	 * Use the key seqno (= cluster wise) if dest is unknown or we're in
+	 * cluster key mode, otherwise it's better for a per-peer seqno!
+	 */
+	if (!__rx || aead->mode == CLUSTER_KEY)
+		seqno = atomic64_inc_return(&aead->seqno);
+	else
+		seqno = atomic64_inc_return(&__rx->sndnxt);
+
+	/* Revoke the key if seqno is wrapped around */
+	if (unlikely(!seqno))
+		return tipc_crypto_key_revoke(net, tx_key);
+
+	/* Word 1-2 */
+	ehdr->seqno = cpu_to_be64(seqno);
+
+	/* Words 0, 3- */
+	ehdr->version = TIPC_EVERSION;
+	ehdr->user = 0;
+	ehdr->keepalive = 0;
+	ehdr->tx_key = tx_key;
+	ehdr->destined = (__rx) ? 1 : 0;
+	ehdr->rx_key_active = (__rx) ? __rx->key.active : 0;
+	ehdr->reserved_1 = 0;
+	ehdr->reserved_2 = 0;
+
+	switch (user) {
+	case LINK_CONFIG:
+		ehdr->user = LINK_CONFIG;
+		memcpy(ehdr->id, tipc_own_id(net), NODE_ID_LEN);
+		break;
+	default:
+		if (user == LINK_PROTOCOL && msg_type(hdr) == STATE_MSG) {
+			ehdr->user = LINK_PROTOCOL;
+			ehdr->keepalive = msg_is_keepalive(hdr);
+		}
+		ehdr->addr = hdr->hdr[3];
+		break;
+	}
+
+	return ehsz;
+}
+
+static inline void tipc_crypto_key_set_state(struct tipc_crypto *c,
+					     u8 new_passive,
+					     u8 new_active,
+					     u8 new_pending)
+{
+#ifdef TIPC_CRYPTO_DEBUG
+	struct tipc_key old = c->key;
+	char buf[32];
+#endif
+
+	c->key.keys = ((new_passive & KEY_MASK) << (KEY_BITS * 2)) |
+		      ((new_active  & KEY_MASK) << (KEY_BITS)) |
+		      ((new_pending & KEY_MASK));
+
+#ifdef TIPC_CRYPTO_DEBUG
+	pr_info("%s(%s): key changing %s ::%pS\n",
+		(c->node) ? "RX" : "TX",
+		(c->node) ? tipc_node_get_id_str(c->node) :
+			    tipc_own_id_string(c->net),
+		tipc_key_change_dump(old, c->key, buf),
+		__builtin_return_address(0));
+#endif
+}
+
+/**
+ * tipc_crypto_key_init - Initiate a new user / AEAD key
+ * @c: TIPC crypto to which new key is attached
+ * @ukey: the user key
+ * @mode: the key mode (CLUSTER_KEY or PER_NODE_KEY)
+ *
+ * A new TIPC AEAD key will be allocated and initiated with the specified user
+ * key, then attached to the TIPC crypto.
+ *
+ * Return: new key id in case of success, otherwise: < 0
+ */
+int tipc_crypto_key_init(struct tipc_crypto *c, struct tipc_aead_key *ukey,
+			 u8 mode)
+{
+	struct tipc_aead *aead = NULL;
+	int rc = 0;
+
+	/* Initiate with the new user key */
+	rc = tipc_aead_init(&aead, ukey, mode);
+
+	/* Attach it to the crypto */
+	if (likely(!rc)) {
+		rc = tipc_crypto_key_attach(c, aead, 0);
+		if (rc < 0)
+			tipc_aead_free(&aead->rcu);
+	}
+
+	pr_info("%s(%s): key initiating, rc %d!\n",
+		(c->node) ? "RX" : "TX",
+		(c->node) ? tipc_node_get_id_str(c->node) :
+			    tipc_own_id_string(c->net),
+		rc);
+
+	return rc;
+}
+
+/**
+ * tipc_crypto_key_attach - Attach a new AEAD key to TIPC crypto
+ * @c: TIPC crypto to which the new AEAD key is attached
+ * @aead: the new AEAD key pointer
+ * @pos: desired slot in the crypto key array, = 0 if any!
+ *
+ * Return: new key id in case of success, otherwise: -EBUSY
+ */
+static int tipc_crypto_key_attach(struct tipc_crypto *c,
+				  struct tipc_aead *aead, u8 pos)
+{
+	u8 new_pending, new_passive, new_key;
+	struct tipc_key key;
+	int rc = -EBUSY;
+
+	spin_lock_bh(&c->lock);
+	key = c->key;
+	if (key.active && key.passive)
+		goto exit;
+	if (key.passive && !tipc_aead_users(c->aead[key.passive]))
+		goto exit;
+	if (key.pending) {
+		if (pos)
+			goto exit;
+		if (tipc_aead_users(c->aead[key.pending]) > 0)
+			goto exit;
+		/* Replace it */
+		new_pending = key.pending;
+		new_passive = key.passive;
+		new_key = new_pending;
+	} else {
+		if (pos) {
+			if (key.active && pos != key_next(key.active)) {
+				new_pending = key.pending;
+				new_passive = pos;
+				new_key = new_passive;
+				goto attach;
+			} else if (!key.active && !key.passive) {
+				new_pending = pos;
+				new_passive = key.passive;
+				new_key = new_pending;
+				goto attach;
+			}
+		}
+		new_pending = key_next(key.active ?: key.passive);
+		new_passive = key.passive;
+		new_key = new_pending;
+	}
+
+attach:
+	aead->crypto = c;
+	tipc_crypto_key_set_state(c, new_passive, key.active, new_pending);
+	tipc_aead_rcu_replace(c->aead[new_key], aead, &c->lock);
+
+	c->working = 1;
+	c->timer1 = jiffies;
+	c->timer2 = jiffies;
+	rc = new_key;
+
+exit:
+	spin_unlock_bh(&c->lock);
+	return rc;
+}
+
+void tipc_crypto_key_flush(struct tipc_crypto *c)
+{
+	int k;
+
+	spin_lock_bh(&c->lock);
+	c->working = 0;
+	tipc_crypto_key_set_state(c, 0, 0, 0);
+	for (k = KEY_MIN; k <= KEY_MAX; k++)
+		tipc_crypto_key_detach(c->aead[k], &c->lock);
+	atomic_set(&c->peer_rx_active, 0);
+	atomic64_set(&c->sndnxt, 0);
+	spin_unlock_bh(&c->lock);
+}
+
+/**
+ * tipc_crypto_key_try_align - Align RX keys if possible
+ * @rx: RX crypto handle
+ * @new_pending: new pending slot if aligned (= TX key from peer)
+ *
+ * Peer has used an unknown key slot, this only happens when peer has left and
+ * rejoned, or we are newcomer.
+ * That means, there must be no active key but a pending key at unaligned slot.
+ * If so, we try to move the pending key to the new slot.
+ * Note: A potential passive key can exist, it will be shifted correspondingly!
+ *
+ * Return: "true" if key is successfully aligned, otherwise "false"
+ */
+static bool tipc_crypto_key_try_align(struct tipc_crypto *rx, u8 new_pending)
+{
+	struct tipc_aead *tmp1, *tmp2 = NULL;
+	struct tipc_key key;
+	bool aligned = false;
+	u8 new_passive = 0;
+	int x;
+
+	spin_lock(&rx->lock);
+	key = rx->key;
+	if (key.pending == new_pending) {
+		aligned = true;
+		goto exit;
+	}
+	if (key.active)
+		goto exit;
+	if (!key.pending)
+		goto exit;
+	if (tipc_aead_users(rx->aead[key.pending]) > 0)
+		goto exit;
+
+	/* Try to "isolate" this pending key first */
+	tmp1 = tipc_aead_rcu_ptr(rx->aead[key.pending], &rx->lock);
+	if (!refcount_dec_if_one(&tmp1->refcnt))
+		goto exit;
+	rcu_assign_pointer(rx->aead[key.pending], NULL);
+
+	/* Move passive key if any */
+	if (key.passive) {
+		tipc_aead_rcu_swap(rx->aead[key.passive], tmp2, &rx->lock);
+		x = (key.passive - key.pending + new_pending) % KEY_MAX;
+		new_passive = (x <= 0) ? x + KEY_MAX : x;
+	}
+
+	/* Re-allocate the key(s) */
+	tipc_crypto_key_set_state(rx, new_passive, 0, new_pending);
+	rcu_assign_pointer(rx->aead[new_pending], tmp1);
+	if (new_passive)
+		rcu_assign_pointer(rx->aead[new_passive], tmp2);
+	refcount_set(&tmp1->refcnt, 1);
+	aligned = true;
+	pr_info("RX(%s): key is aligned!\n", tipc_node_get_id_str(rx->node));
+
+exit:
+	spin_unlock(&rx->lock);
+	return aligned;
+}
+
+/**
+ * tipc_crypto_key_pick_tx - Pick one TX key for message decryption
+ * @tx: TX crypto handle
+ * @rx: RX crypto handle (can be NULL)
+ * @skb: the message skb which will be decrypted later
+ *
+ * This function looks up the existing TX keys and pick one which is suitable
+ * for the message decryption, that must be a cluster key and not used before
+ * on the same message (i.e. recursive).
+ *
+ * Return: the TX AEAD key handle in case of success, otherwise NULL
+ */
+static struct tipc_aead *tipc_crypto_key_pick_tx(struct tipc_crypto *tx,
+						 struct tipc_crypto *rx,
+						 struct sk_buff *skb)
+{
+	struct tipc_skb_cb *skb_cb = TIPC_SKB_CB(skb);
+	struct tipc_aead *aead = NULL;
+	struct tipc_key key = tx->key;
+	u8 k, i = 0;
+
+	/* Initialize data if not yet */
+	if (!skb_cb->tx_clone_deferred) {
+		skb_cb->tx_clone_deferred = 1;
+		memset(&skb_cb->tx_clone_ctx, 0, sizeof(skb_cb->tx_clone_ctx));
+	}
+
+	skb_cb->tx_clone_ctx.rx = rx;
+	if (++skb_cb->tx_clone_ctx.recurs > 2)
+		return NULL;
+
+	/* Pick one TX key */
+	spin_lock(&tx->lock);
+	do {
+		k = (i == 0) ? key.pending :
+			((i == 1) ? key.active : key.passive);
+		if (!k)
+			continue;
+		aead = tipc_aead_rcu_ptr(tx->aead[k], &tx->lock);
+		if (!aead)
+			continue;
+		if (aead->mode != CLUSTER_KEY ||
+		    aead == skb_cb->tx_clone_ctx.last) {
+			aead = NULL;
+			continue;
+		}
+		/* Ok, found one cluster key */
+		skb_cb->tx_clone_ctx.last = aead;
+		WARN_ON(skb->next);
+		skb->next = skb_clone(skb, GFP_ATOMIC);
+		if (unlikely(!skb->next))
+			pr_warn("Failed to clone skb for next round if any\n");
+		WARN_ON(!refcount_inc_not_zero(&aead->refcnt));
+		break;
+	} while (++i < 3);
+	spin_unlock(&tx->lock);
+
+	return aead;
+}
+
+/**
+ * tipc_crypto_key_synch: Synch own key data according to peer key status
+ * @rx: RX crypto handle
+ * @new_rx_active: latest RX active key from peer
+ * @hdr: TIPCv2 message
+ *
+ * This function updates the peer node related data as the peer RX active key
+ * has changed, so the number of TX keys' users on this node are increased and
+ * decreased correspondingly.
+ *
+ * The "per-peer" sndnxt is also reset when the peer key has switched.
+ */
+static void tipc_crypto_key_synch(struct tipc_crypto *rx, u8 new_rx_active,
+				  struct tipc_msg *hdr)
+{
+	struct net *net = rx->net;
+	struct tipc_crypto *tx = tipc_net(net)->crypto_tx;
+	u8 cur_rx_active;
+
+	/* TX might be even not ready yet */
+	if (unlikely(!tx->key.active && !tx->key.pending))
+		return;
+
+	cur_rx_active = atomic_read(&rx->peer_rx_active);
+	if (likely(cur_rx_active == new_rx_active))
+		return;
+
+	/* Make sure this message destined for this node */
+	if (unlikely(msg_short(hdr) ||
+		     msg_destnode(hdr) != tipc_own_addr(net)))
+		return;
+
+	/* Peer RX active key has changed, try to update owns' & TX users */
+	if (atomic_cmpxchg(&rx->peer_rx_active,
+			   cur_rx_active,
+			   new_rx_active) == cur_rx_active) {
+		if (new_rx_active)
+			tipc_aead_users_inc(tx->aead[new_rx_active], INT_MAX);
+		if (cur_rx_active)
+			tipc_aead_users_dec(tx->aead[cur_rx_active], 0);
+
+		atomic64_set(&rx->sndnxt, 0);
+		/* Mark the point TX key users changed */
+		tx->timer1 = jiffies;
+
+#ifdef TIPC_CRYPTO_DEBUG
+		pr_info("TX(%s): key users changed %d-- %d++, peer RX(%s)\n",
+			tipc_own_id_string(net), cur_rx_active,
+			new_rx_active, tipc_node_get_id_str(rx->node));
+#endif
+	}
+}
+
+static int tipc_crypto_key_revoke(struct net *net, u8 tx_key)
+{
+	struct tipc_crypto *tx = tipc_net(net)->crypto_tx;
+	struct tipc_key key;
+
+	spin_lock(&tx->lock);
+	key = tx->key;
+	WARN_ON(!key.active || tx_key != key.active);
+
+	/* Free the active key */
+	tipc_crypto_key_set_state(tx, key.passive, 0, key.pending);
+	tipc_crypto_key_detach(tx->aead[key.active], &tx->lock);
+	spin_unlock(&tx->lock);
+
+	pr_warn("TX(%s): key is revoked!\n", tipc_own_id_string(net));
+	return -EKEYREVOKED;
+}
+
+int tipc_crypto_start(struct tipc_crypto **crypto, struct net *net,
+		      struct tipc_node *node)
+{
+	struct tipc_crypto *c;
+
+	if (*crypto)
+		return -EEXIST;
+
+	/* Allocate crypto */
+	c = kzalloc(sizeof(*c), GFP_ATOMIC);
+	if (!c)
+		return -ENOMEM;
+
+	/* Allocate statistic structure */
+	c->stats = alloc_percpu_gfp(struct tipc_crypto_stats, GFP_ATOMIC);
+	if (!c->stats) {
+		kzfree(c);
+		return -ENOMEM;
+	}
+
+	c->working = 0;
+	c->net = net;
+	c->node = node;
+	tipc_crypto_key_set_state(c, 0, 0, 0);
+	atomic_set(&c->peer_rx_active, 0);
+	atomic64_set(&c->sndnxt, 0);
+	c->timer1 = jiffies;
+	c->timer2 = jiffies;
+	spin_lock_init(&c->lock);
+	*crypto = c;
+
+	return 0;
+}
+
+void tipc_crypto_stop(struct tipc_crypto **crypto)
+{
+	struct tipc_crypto *c, *tx, *rx;
+	bool is_rx;
+	u8 k;
+
+	if (!*crypto)
+		return;
+
+	rcu_read_lock();
+	/* RX stopping? => decrease TX key users if any */
+	is_rx = !!((*crypto)->node);
+	if (is_rx) {
+		rx = *crypto;
+		tx = tipc_net(rx->net)->crypto_tx;
+		k = atomic_read(&rx->peer_rx_active);
+		if (k) {
+			tipc_aead_users_dec(tx->aead[k], 0);
+			/* Mark the point TX key users changed */
+			tx->timer1 = jiffies;
+		}
+	}
+
+	/* Release AEAD keys */
+	c = *crypto;
+	for (k = KEY_MIN; k <= KEY_MAX; k++)
+		tipc_aead_put(rcu_dereference(c->aead[k]));
+	rcu_read_unlock();
+
+	pr_warn("%s(%s) has been purged, node left!\n",
+		(is_rx) ? "RX" : "TX",
+		(is_rx) ? tipc_node_get_id_str((*crypto)->node) :
+			  tipc_own_id_string((*crypto)->net));
+
+	/* Free this crypto statistics */
+	free_percpu(c->stats);
+
+	*crypto = NULL;
+	kzfree(c);
+}
+
+void tipc_crypto_timeout(struct tipc_crypto *rx)
+{
+	struct tipc_net *tn = tipc_net(rx->net);
+	struct tipc_crypto *tx = tn->crypto_tx;
+	struct tipc_key key;
+	u8 new_pending, new_passive;
+	int cmd;
+
+	/* TX key activating:
+	 * The pending key (users > 0) -> active
+	 * The active key if any (users == 0) -> free
+	 */
+	spin_lock(&tx->lock);
+	key = tx->key;
+	if (key.active && tipc_aead_users(tx->aead[key.active]) > 0)
+		goto s1;
+	if (!key.pending || tipc_aead_users(tx->aead[key.pending]) <= 0)
+		goto s1;
+	if (time_before(jiffies, tx->timer1 + TIPC_TX_LASTING_LIM))
+		goto s1;
+
+	tipc_crypto_key_set_state(tx, key.passive, key.pending, 0);
+	if (key.active)
+		tipc_crypto_key_detach(tx->aead[key.active], &tx->lock);
+	this_cpu_inc(tx->stats->stat[STAT_SWITCHES]);
+	pr_info("TX(%s): key %d is activated!\n", tipc_own_id_string(tx->net),
+		key.pending);
+
+s1:
+	spin_unlock(&tx->lock);
+
+	/* RX key activating:
+	 * The pending key (users > 0) -> active
+	 * The active key if any -> passive, freed later
+	 */
+	spin_lock(&rx->lock);
+	key = rx->key;
+	if (!key.pending || tipc_aead_users(rx->aead[key.pending]) <= 0)
+		goto s2;
+
+	new_pending = (key.passive &&
+		       !tipc_aead_users(rx->aead[key.passive])) ?
+				       key.passive : 0;
+	new_passive = (key.active) ?: ((new_pending) ? 0 : key.passive);
+	tipc_crypto_key_set_state(rx, new_passive, key.pending, new_pending);
+	this_cpu_inc(rx->stats->stat[STAT_SWITCHES]);
+	pr_info("RX(%s): key %d is activated!\n",
+		tipc_node_get_id_str(rx->node),	key.pending);
+	goto s5;
+
+s2:
+	/* RX key "faulty" switching:
+	 * The faulty pending key (users < -30) -> passive
+	 * The passive key (users = 0) -> pending
+	 * Note: This only happens after RX deactivated - s3!
+	 */
+	key = rx->key;
+	if (!key.pending || tipc_aead_users(rx->aead[key.pending]) > -30)
+		goto s3;
+	if (!key.passive || tipc_aead_users(rx->aead[key.passive]) != 0)
+		goto s3;
+
+	new_pending = key.passive;
+	new_passive = key.pending;
+	tipc_crypto_key_set_state(rx, new_passive, key.active, new_pending);
+	goto s5;
+
+s3:
+	/* RX key deactivating:
+	 * The passive key if any -> pending
+	 * The active key -> passive (users = 0) / pending
+	 * The pending key if any -> passive (users = 0)
+	 */
+	key = rx->key;
+	if (!key.active)
+		goto s4;
+	if (time_before(jiffies, rx->timer1 + TIPC_RX_ACTIVE_LIM))
+		goto s4;
+
+	new_pending = (key.passive) ?: key.active;
+	new_passive = (key.passive) ? key.active : key.pending;
+	tipc_aead_users_set(rx->aead[new_pending], 0);
+	if (new_passive)
+		tipc_aead_users_set(rx->aead[new_passive], 0);
+	tipc_crypto_key_set_state(rx, new_passive, 0, new_pending);
+	pr_info("RX(%s): key %d is deactivated!\n",
+		tipc_node_get_id_str(rx->node), key.active);
+	goto s5;
+
+s4:
+	/* RX key passive -> freed: */
+	key = rx->key;
+	if (!key.passive || !tipc_aead_users(rx->aead[key.passive]))
+		goto s5;
+	if (time_before(jiffies, rx->timer2 + TIPC_RX_PASSIVE_LIM))
+		goto s5;
+
+	tipc_crypto_key_set_state(rx, 0, key.active, key.pending);
+	tipc_crypto_key_detach(rx->aead[key.passive], &rx->lock);
+	pr_info("RX(%s): key %d is freed!\n", tipc_node_get_id_str(rx->node),
+		key.passive);
+
+s5:
+	spin_unlock(&rx->lock);
+
+	/* Limit max_tfms & do debug commands if needed */
+	if (likely(sysctl_tipc_max_tfms <= TIPC_MAX_TFMS_LIM))
+		return;
+
+	cmd = sysctl_tipc_max_tfms;
+	sysctl_tipc_max_tfms = TIPC_MAX_TFMS_DEF;
+	tipc_crypto_do_cmd(rx->net, cmd);
+}
+
+/**
+ * tipc_crypto_xmit - Build & encrypt TIPC message for xmit
+ * @net: struct net
+ * @skb: input/output message skb pointer
+ * @b: bearer used for xmit later
+ * @dst: destination media address
+ * @__dnode: destination node for reference if any
+ *
+ * First, build an encryption message header on the top of the message, then
+ * encrypt the original TIPC message by using the active or pending TX key.
+ * If the encryption is successful, the encrypted skb is returned directly or
+ * via the callback.
+ * Otherwise, the skb is freed!
+ *
+ * Return:
+ * 0                   : the encryption has succeeded (or no encryption)
+ * -EINPROGRESS/-EBUSY : the encryption is ongoing, a callback will be made
+ * -ENOKEK             : the encryption has failed due to no key
+ * -EKEYREVOKED        : the encryption has failed due to key revoked
+ * -ENOMEM             : the encryption has failed due to no memory
+ * < 0                 : the encryption has failed due to other reasons
+ */
+int tipc_crypto_xmit(struct net *net, struct sk_buff **skb,
+		     struct tipc_bearer *b, struct tipc_media_addr *dst,
+		     struct tipc_node *__dnode)
+{
+	struct tipc_crypto *__rx = tipc_node_crypto_rx(__dnode);
+	struct tipc_crypto *tx = tipc_net(net)->crypto_tx;
+	struct tipc_crypto_stats __percpu *stats = tx->stats;
+	struct tipc_key key = tx->key;
+	struct tipc_aead *aead = NULL;
+	struct sk_buff *probe;
+	int rc = -ENOKEY;
+	u8 tx_key;
+
+	/* No encryption? */
+	if (!tx->working)
+		return 0;
+
+	/* Try with the pending key if available and:
+	 * 1) This is the only choice (i.e. no active key) or;
+	 * 2) Peer has switched to this key (unicast only) or;
+	 * 3) It is time to do a pending key probe;
+	 */
+	if (unlikely(key.pending)) {
+		tx_key = key.pending;
+		if (!key.active)
+			goto encrypt;
+		if (__rx && atomic_read(&__rx->peer_rx_active) == tx_key)
+			goto encrypt;
+		if (TIPC_SKB_CB(*skb)->probe)
+			goto encrypt;
+		if (!__rx &&
+		    time_after(jiffies, tx->timer2 + TIPC_TX_PROBE_LIM)) {
+			tx->timer2 = jiffies;
+			probe = skb_clone(*skb, GFP_ATOMIC);
+			if (probe) {
+				TIPC_SKB_CB(probe)->probe = 1;
+				tipc_crypto_xmit(net, &probe, b, dst, __dnode);
+				if (probe)
+					b->media->send_msg(net, probe, b, dst);
+			}
+		}
+	}
+	/* Else, use the active key if any */
+	if (likely(key.active)) {
+		tx_key = key.active;
+		goto encrypt;
+	}
+	goto exit;
+
+encrypt:
+	aead = tipc_aead_get(tx->aead[tx_key]);
+	if (unlikely(!aead))
+		goto exit;
+	rc = tipc_ehdr_build(net, aead, tx_key, *skb, __rx);
+	if (likely(rc > 0))
+		rc = tipc_aead_encrypt(aead, *skb, b, dst, __dnode);
+
+exit:
+	switch (rc) {
+	case 0:
+		this_cpu_inc(stats->stat[STAT_OK]);
+		break;
+	case -EINPROGRESS:
+	case -EBUSY:
+		this_cpu_inc(stats->stat[STAT_ASYNC]);
+		*skb = NULL;
+		return rc;
+	default:
+		this_cpu_inc(stats->stat[STAT_NOK]);
+		if (rc == -ENOKEY)
+			this_cpu_inc(stats->stat[STAT_NOKEYS]);
+		else if (rc == -EKEYREVOKED)
+			this_cpu_inc(stats->stat[STAT_BADKEYS]);
+		kfree_skb(*skb);
+		*skb = NULL;
+		break;
+	}
+
+	tipc_aead_put(aead);
+	return rc;
+}
+
+/**
+ * tipc_crypto_rcv - Decrypt an encrypted TIPC message from peer
+ * @net: struct net
+ * @rx: RX crypto handle
+ * @skb: input/output message skb pointer
+ * @b: bearer where the message has been received
+ *
+ * If the decryption is successful, the decrypted skb is returned directly or
+ * as the callback, the encryption header and auth tag will be trimed out
+ * before forwarding to tipc_rcv() via the tipc_crypto_rcv_complete().
+ * Otherwise, the skb will be freed!
+ * Note: RX key(s) can be re-aligned, or in case of no key suitable, TX
+ * cluster key(s) can be taken for decryption (- recursive).
+ *
+ * Return:
+ * 0                   : the decryption has successfully completed
+ * -EINPROGRESS/-EBUSY : the decryption is ongoing, a callback will be made
+ * -ENOKEY             : the decryption has failed due to no key
+ * -EBADMSG            : the decryption has failed due to bad message
+ * -ENOMEM             : the decryption has failed due to no memory
+ * < 0                 : the decryption has failed due to other reasons
+ */
+int tipc_crypto_rcv(struct net *net, struct tipc_crypto *rx,
+		    struct sk_buff **skb, struct tipc_bearer *b)
+{
+	struct tipc_crypto *tx = tipc_net(net)->crypto_tx;
+	struct tipc_crypto_stats __percpu *stats;
+	struct tipc_aead *aead = NULL;
+	struct tipc_key key;
+	int rc = -ENOKEY;
+	u8 tx_key = 0;
+
+	/* New peer?
+	 * Let's try with TX key (i.e. cluster mode) & verify the skb first!
+	 */
+	if (unlikely(!rx))
+		goto pick_tx;
+
+	/* Pick RX key according to TX key, three cases are possible:
+	 * 1) The current active key (likely) or;
+	 * 2) The pending (new or deactivated) key (if any) or;
+	 * 3) The passive or old active key (i.e. users > 0);
+	 */
+	tx_key = ((struct tipc_ehdr *)(*skb)->data)->tx_key;
+	key = rx->key;
+	if (likely(tx_key == key.active))
+		goto decrypt;
+	if (tx_key == key.pending)
+		goto decrypt;
+	if (tx_key == key.passive) {
+		rx->timer2 = jiffies;
+		if (tipc_aead_users(rx->aead[key.passive]) > 0)
+			goto decrypt;
+	}
+
+	/* Unknown key, let's try to align RX key(s) */
+	if (tipc_crypto_key_try_align(rx, tx_key))
+		goto decrypt;
+
+pick_tx:
+	/* No key suitable? Try to pick one from TX... */
+	aead = tipc_crypto_key_pick_tx(tx, rx, *skb);
+	if (aead)
+		goto decrypt;
+	goto exit;
+
+decrypt:
+	rcu_read_lock();
+	if (!aead)
+		aead = tipc_aead_get(rx->aead[tx_key]);
+	rc = tipc_aead_decrypt(net, aead, *skb, b);
+	rcu_read_unlock();
+
+exit:
+	stats = ((rx) ?: tx)->stats;
+	switch (rc) {
+	case 0:
+		this_cpu_inc(stats->stat[STAT_OK]);
+		break;
+	case -EINPROGRESS:
+	case -EBUSY:
+		this_cpu_inc(stats->stat[STAT_ASYNC]);
+		*skb = NULL;
+		return rc;
+	default:
+		this_cpu_inc(stats->stat[STAT_NOK]);
+		if (rc == -ENOKEY) {
+			kfree_skb(*skb);
+			*skb = NULL;
+			if (rx)
+				tipc_node_put(rx->node);
+			this_cpu_inc(stats->stat[STAT_NOKEYS]);
+			return rc;
+		} else if (rc == -EBADMSG) {
+			this_cpu_inc(stats->stat[STAT_BADMSGS]);
+		}
+		break;
+	}
+
+	tipc_crypto_rcv_complete(net, aead, b, skb, rc);
+	return rc;
+}
+
+static void tipc_crypto_rcv_complete(struct net *net, struct tipc_aead *aead,
+				     struct tipc_bearer *b,
+				     struct sk_buff **skb, int err)
+{
+	struct tipc_skb_cb *skb_cb = TIPC_SKB_CB(*skb);
+	struct tipc_crypto *rx = aead->crypto;
+	struct tipc_aead *tmp = NULL;
+	struct tipc_ehdr *ehdr;
+	struct tipc_node *n;
+	u8 rx_key_active;
+	bool destined;
+
+	/* Is this completed by TX? */
+	if (unlikely(!rx->node)) {
+		rx = skb_cb->tx_clone_ctx.rx;
+#ifdef TIPC_CRYPTO_DEBUG
+		pr_info("TX->RX(%s): err %d, aead %p, skb->next %p, flags %x\n",
+			(rx) ? tipc_node_get_id_str(rx->node) : "-", err, aead,
+			(*skb)->next, skb_cb->flags);
+		pr_info("skb_cb [recurs %d, last %p], tx->aead [%p %p %p]\n",
+			skb_cb->tx_clone_ctx.recurs, skb_cb->tx_clone_ctx.last,
+			aead->crypto->aead[1], aead->crypto->aead[2],
+			aead->crypto->aead[3]);
+#endif
+		if (unlikely(err)) {
+			if (err == -EBADMSG && (*skb)->next)
+				tipc_rcv(net, (*skb)->next, b);
+			goto free_skb;
+		}
+
+		if (likely((*skb)->next)) {
+			kfree_skb((*skb)->next);
+			(*skb)->next = NULL;
+		}
+		ehdr = (struct tipc_ehdr *)(*skb)->data;
+		if (!rx) {
+			WARN_ON(ehdr->user != LINK_CONFIG);
+			n = tipc_node_create(net, 0, ehdr->id, 0xffffu, 0,
+					     true);
+			rx = tipc_node_crypto_rx(n);
+			if (unlikely(!rx))
+				goto free_skb;
+		}
+
+		/* Skip cloning this time as we had a RX pending key */
+		if (rx->key.pending)
+			goto rcv;
+		if (tipc_aead_clone(&tmp, aead) < 0)
+			goto rcv;
+		if (tipc_crypto_key_attach(rx, tmp, ehdr->tx_key) < 0) {
+			tipc_aead_free(&tmp->rcu);
+			goto rcv;
+		}
+		tipc_aead_put(aead);
+		aead = tipc_aead_get(tmp);
+	}
+
+	if (unlikely(err)) {
+		tipc_aead_users_dec(aead, INT_MIN);
+		goto free_skb;
+	}
+
+	/* Set the RX key's user */
+	tipc_aead_users_set(aead, 1);
+
+rcv:
+	/* Mark this point, RX works */
+	rx->timer1 = jiffies;
+
+	/* Remove ehdr & auth. tag prior to tipc_rcv() */
+	ehdr = (struct tipc_ehdr *)(*skb)->data;
+	destined = ehdr->destined;
+	rx_key_active = ehdr->rx_key_active;
+	skb_pull(*skb, tipc_ehdr_size(ehdr));
+	pskb_trim(*skb, (*skb)->len - aead->authsize);
+
+	/* Validate TIPCv2 message */
+	if (unlikely(!tipc_msg_validate(skb))) {
+		pr_err_ratelimited("Packet dropped after decryption!\n");
+		goto free_skb;
+	}
+
+	/* Update peer RX active key & TX users */
+	if (destined)
+		tipc_crypto_key_synch(rx, rx_key_active, buf_msg(*skb));
+
+	/* Mark skb decrypted */
+	skb_cb->decrypted = 1;
+
+	/* Clear clone cxt if any */
+	if (likely(!skb_cb->tx_clone_deferred))
+		goto exit;
+	skb_cb->tx_clone_deferred = 0;
+	memset(&skb_cb->tx_clone_ctx, 0, sizeof(skb_cb->tx_clone_ctx));
+	goto exit;
+
+free_skb:
+	kfree_skb(*skb);
+	*skb = NULL;
+
+exit:
+	tipc_aead_put(aead);
+	if (rx)
+		tipc_node_put(rx->node);
+}
+
+static void tipc_crypto_do_cmd(struct net *net, int cmd)
+{
+	struct tipc_net *tn = tipc_net(net);
+	struct tipc_crypto *tx = tn->crypto_tx, *rx;
+	struct list_head *p;
+	unsigned int stat;
+	int i, j, cpu;
+	char buf[200];
+
+	/* Currently only one command is supported */
+	switch (cmd) {
+	case 0xfff1:
+		goto print_stats;
+	default:
+		return;
+	}
+
+print_stats:
+	/* Print a header */
+	pr_info("\n=============== TIPC Crypto Statistics ===============\n\n");
+
+	/* Print key status */
+	pr_info("Key status:\n");
+	pr_info("TX(%7.7s)\n%s", tipc_own_id_string(net),
+		tipc_crypto_key_dump(tx, buf));
+
+	rcu_read_lock();
+	for (p = tn->node_list.next; p != &tn->node_list; p = p->next) {
+		rx = tipc_node_crypto_rx_by_list(p);
+		pr_info("RX(%7.7s)\n%s", tipc_node_get_id_str(rx->node),
+			tipc_crypto_key_dump(rx, buf));
+	}
+	rcu_read_unlock();
+
+	/* Print crypto statistics */
+	for (i = 0, j = 0; i < MAX_STATS; i++)
+		j += scnprintf(buf + j, 200 - j, "|%11s ", hstats[i]);
+	pr_info("\nCounter     %s", buf);
+
+	memset(buf, '-', 115);
+	buf[115] = '\0';
+	pr_info("%s\n", buf);
+
+	j = scnprintf(buf, 200, "TX(%7.7s) ", tipc_own_id_string(net));
+	for_each_possible_cpu(cpu) {
+		for (i = 0; i < MAX_STATS; i++) {
+			stat = per_cpu_ptr(tx->stats, cpu)->stat[i];
+			j += scnprintf(buf + j, 200 - j, "|%11d ", stat);
+		}
+		pr_info("%s", buf);
+		j = scnprintf(buf, 200, "%12s", " ");
+	}
+
+	rcu_read_lock();
+	for (p = tn->node_list.next; p != &tn->node_list; p = p->next) {
+		rx = tipc_node_crypto_rx_by_list(p);
+		j = scnprintf(buf, 200, "RX(%7.7s) ",
+			      tipc_node_get_id_str(rx->node));
+		for_each_possible_cpu(cpu) {
+			for (i = 0; i < MAX_STATS; i++) {
+				stat = per_cpu_ptr(rx->stats, cpu)->stat[i];
+				j += scnprintf(buf + j, 200 - j, "|%11d ",
+					       stat);
+			}
+			pr_info("%s", buf);
+			j = scnprintf(buf, 200, "%12s", " ");
+		}
+	}
+	rcu_read_unlock();
+
+	pr_info("\n======================== Done ========================\n");
+}
+
+static char *tipc_crypto_key_dump(struct tipc_crypto *c, char *buf)
+{
+	struct tipc_key key = c->key;
+	struct tipc_aead *aead;
+	int k, i = 0;
+	char *s;
+
+	for (k = KEY_MIN; k <= KEY_MAX; k++) {
+		if (k == key.passive)
+			s = "PAS";
+		else if (k == key.active)
+			s = "ACT";
+		else if (k == key.pending)
+			s = "PEN";
+		else
+			s = "-";
+		i += scnprintf(buf + i, 200 - i, "\tKey%d: %s", k, s);
+
+		rcu_read_lock();
+		aead = rcu_dereference(c->aead[k]);
+		if (aead)
+			i += scnprintf(buf + i, 200 - i,
+				       "{\"%s...\", \"%s\"}/%d:%d",
+				       aead->hint,
+				       (aead->mode == CLUSTER_KEY) ? "c" : "p",
+				       atomic_read(&aead->users),
+				       refcount_read(&aead->refcnt));
+		rcu_read_unlock();
+		i += scnprintf(buf + i, 200 - i, "\n");
+	}
+
+	if (c->node)
+		i += scnprintf(buf + i, 200 - i, "\tPeer RX active: %d\n",
+			       atomic_read(&c->peer_rx_active));
+
+	return buf;
+}
+
+#ifdef TIPC_CRYPTO_DEBUG
+static char *tipc_key_change_dump(struct tipc_key old, struct tipc_key new,
+				  char *buf)
+{
+	struct tipc_key *key = &old;
+	int k, i = 0;
+	char *s;
+
+	/* Output format: "[%s %s %s] -> [%s %s %s]", max len = 32 */
+again:
+	i += scnprintf(buf + i, 32 - i, "[");
+	for (k = KEY_MIN; k <= KEY_MAX; k++) {
+		if (k == key->passive)
+			s = "pas";
+		else if (k == key->active)
+			s = "act";
+		else if (k == key->pending)
+			s = "pen";
+		else
+			s = "-";
+		i += scnprintf(buf + i, 32 - i,
+			       (k != KEY_MAX) ? "%s " : "%s", s);
+	}
+	if (key != &new) {
+		i += scnprintf(buf + i, 32 - i, "] -> ");
+		key = &new;
+		goto again;
+	}
+	i += scnprintf(buf + i, 32 - i, "]");
+	return buf;
+}
+#endif
diff --git a/net/tipc/crypto.h b/net/tipc/crypto.h
new file mode 100644
index 000000000000..c3de769f49e8
--- /dev/null
+++ b/net/tipc/crypto.h
@@ -0,0 +1,167 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/**
+ * net/tipc/crypto.h: Include file for TIPC crypto
+ *
+ * Copyright (c) 2019, Ericsson AB
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#ifdef CONFIG_TIPC_CRYPTO
+#ifndef _TIPC_CRYPTO_H
+#define _TIPC_CRYPTO_H
+
+#include "core.h"
+#include "node.h"
+#include "msg.h"
+#include "bearer.h"
+
+#define TIPC_EVERSION			7
+
+/* AEAD aes(gcm) */
+#define TIPC_AES_GCM_KEY_SIZE_128	16
+#define TIPC_AES_GCM_KEY_SIZE_192	24
+#define TIPC_AES_GCM_KEY_SIZE_256	32
+
+#define TIPC_AES_GCM_SALT_SIZE		4
+#define TIPC_AES_GCM_IV_SIZE		12
+#define TIPC_AES_GCM_TAG_SIZE		16
+
+/**
+ * TIPC crypto modes:
+ * - CLUSTER_KEY:
+ *	One single key is used for both TX & RX in all nodes in the cluster.
+ * - PER_NODE_KEY:
+ *	Each nodes in the cluster has one TX key, for RX a node needs to know
+ *	its peers' TX key for the decryption of messages from those nodes.
+ */
+enum {
+	CLUSTER_KEY = 1,
+	PER_NODE_KEY = (1 << 1),
+};
+
+extern int sysctl_tipc_max_tfms __read_mostly;
+
+/**
+ * TIPC encryption message format:
+ *
+ *     3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0
+ *     1 0 9 8 7 6 5 4|3 2 1 0 9 8 7 6|5 4 3 2 1 0 9 8|7 6 5 4 3 2 1 0
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * w0:|Ver=7| User  |D|TX |RX |K|                 Rsvd                |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * w1:|                             Seqno                             |
+ * w2:|                           (8 octets)                          |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * w3:\                            Prevnode                           \
+ *    /                        (4 or 16 octets)                       /
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    \                                                               \
+ *    /       Encrypted complete TIPC V2 header and user data         /
+ *    \                                                               \
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    |                                                               |
+ *    |                             AuthTag                           |
+ *    |                           (16 octets)                         |
+ *    |                                                               |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * Word0:
+ *	Ver	: = 7 i.e. TIPC encryption message version
+ *	User	: = 7 (for LINK_PROTOCOL); = 13 (for LINK_CONFIG) or = 0
+ *	D	: The destined bit i.e. the message's destination node is
+ *	          "known" or not at the message encryption
+ *	TX	: TX key used for the message encryption
+ *	RX	: Currently RX active key corresponding to the destination
+ *	          node's TX key (when the "D" bit is set)
+ *	K	: Keep-alive bit (for RPS, LINK_PROTOCOL/STATE_MSG only)
+ *	Rsvd	: Reserved bit, field
+ * Word1-2:
+ *	Seqno	: The 64-bit sequence number of the encrypted message, also
+ *		  part of the nonce used for the message encryption/decryption
+ * Word3-:
+ *	Prevnode: The source node address, or ID in case LINK_CONFIG only
+ *	AuthTag	: The authentication tag for the message integrity checking
+ *		  generated by the message encryption
+ */
+struct tipc_ehdr {
+	union {
+		struct {
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+			__u8	destined:1,
+				user:4,
+				version:3;
+			__u8	reserved_1:3,
+				keepalive:1,
+				rx_key_active:2,
+				tx_key:2;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+			__u8	version:3,
+				user:4,
+				destined:1;
+			__u8	tx_key:2,
+				rx_key_active:2,
+				keepalive:1,
+				reserved_1:3;
+#else
+#error  "Please fix <asm/byteorder.h>"
+#endif
+			__be16	reserved_2;
+		} __packed;
+		__be32 w0;
+	};
+	__be64 seqno;
+	union {
+		__be32 addr;
+		__u8 id[NODE_ID_LEN]; /* For a LINK_CONFIG message only! */
+	};
+#define EHDR_SIZE	(offsetof(struct tipc_ehdr, addr) + sizeof(__be32))
+#define EHDR_CFG_SIZE	(sizeof(struct tipc_ehdr))
+#define EHDR_MIN_SIZE	(EHDR_SIZE)
+#define EHDR_MAX_SIZE	(EHDR_CFG_SIZE)
+#define EMSG_OVERHEAD	(EHDR_SIZE + TIPC_AES_GCM_TAG_SIZE)
+} __packed;
+
+int tipc_crypto_start(struct tipc_crypto **crypto, struct net *net,
+		      struct tipc_node *node);
+void tipc_crypto_stop(struct tipc_crypto **crypto);
+void tipc_crypto_timeout(struct tipc_crypto *rx);
+int tipc_crypto_xmit(struct net *net, struct sk_buff **skb,
+		     struct tipc_bearer *b, struct tipc_media_addr *dst,
+		     struct tipc_node *__dnode);
+int tipc_crypto_rcv(struct net *net, struct tipc_crypto *rx,
+		    struct sk_buff **skb, struct tipc_bearer *b);
+int tipc_crypto_key_init(struct tipc_crypto *c, struct tipc_aead_key *ukey,
+			 u8 mode);
+void tipc_crypto_key_flush(struct tipc_crypto *c);
+int tipc_aead_key_validate(struct tipc_aead_key *ukey);
+bool tipc_ehdr_validate(struct sk_buff *skb);
+
+#endif /* _TIPC_CRYPTO_H */
+#endif
diff --git a/net/tipc/link.c b/net/tipc/link.c
index e7bb4cbb7716..fb72031228c9 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -44,6 +44,7 @@
 #include "netlink.h"
 #include "monitor.h"
 #include "trace.h"
+#include "crypto.h"
 
 #include <linux/pkt_sched.h>
 
@@ -397,6 +398,15 @@ int tipc_link_mtu(struct tipc_link *l)
 	return l->mtu;
 }
 
+int tipc_link_mss(struct tipc_link *l)
+{
+#ifdef CONFIG_TIPC_CRYPTO
+	return l->mtu - INT_H_SIZE - EMSG_OVERHEAD;
+#else
+	return l->mtu - INT_H_SIZE;
+#endif
+}
+
 u16 tipc_link_rcv_nxt(struct tipc_link *l)
 {
 	return l->rcv_nxt;
@@ -948,6 +958,7 @@ int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
 	u16 seqno = l->snd_nxt;
 	int pkt_cnt = skb_queue_len(list);
 	int imp = msg_importance(hdr);
+	unsigned int mss = tipc_link_mss(l);
 	unsigned int maxwin = l->window;
 	unsigned int mtu = l->mtu;
 	bool new_bundle;
@@ -1000,8 +1011,7 @@ int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
 			continue;
 		}
 		if (tipc_msg_try_bundle(l->backlog[imp].target_bskb, &skb,
-					mtu - INT_H_SIZE, l->addr,
-					&new_bundle)) {
+					mss, l->addr, &new_bundle)) {
 			if (skb) {
 				/* Keep a ref. to the skb for next try */
 				l->backlog[imp].target_bskb = skb;
@@ -1154,7 +1164,7 @@ static int tipc_link_bc_retrans(struct tipc_link *l, struct tipc_link *r,
 		if (time_before(jiffies, TIPC_SKB_CB(skb)->nxt_retr))
 			continue;
 		TIPC_SKB_CB(skb)->nxt_retr = TIPC_BC_RETR_LIM;
-		_skb = __pskb_copy(skb, LL_MAX_HEADER + MIN_H_SIZE, GFP_ATOMIC);
+		_skb = pskb_copy(skb, GFP_ATOMIC);
 		if (!_skb)
 			return 0;
 		hdr = buf_msg(_skb);
@@ -1430,8 +1440,7 @@ next_gap_ack:
 			if (time_before(jiffies, TIPC_SKB_CB(skb)->nxt_retr))
 				continue;
 			TIPC_SKB_CB(skb)->nxt_retr = TIPC_UC_RETR_TIME;
-			_skb = __pskb_copy(skb, LL_MAX_HEADER + MIN_H_SIZE,
-					   GFP_ATOMIC);
+			_skb = pskb_copy(skb, GFP_ATOMIC);
 			if (!_skb)
 				continue;
 			hdr = buf_msg(_skb);
diff --git a/net/tipc/link.h b/net/tipc/link.h
index adcad65e761c..c09e9d49d0a3 100644
--- a/net/tipc/link.h
+++ b/net/tipc/link.h
@@ -141,6 +141,7 @@ void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
 int tipc_link_bc_peers(struct tipc_link *l);
 void tipc_link_set_mtu(struct tipc_link *l, int mtu);
 int tipc_link_mtu(struct tipc_link *l);
+int tipc_link_mss(struct tipc_link *l);
 void tipc_link_bc_ack_rcv(struct tipc_link *l, u16 acked,
 			  struct sk_buff_head *xmitq);
 void tipc_link_build_bc_sync_msg(struct tipc_link *l,
diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index acb7be592fb1..0d515d20b056 100644
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -39,10 +39,16 @@
 #include "msg.h"
 #include "addr.h"
 #include "name_table.h"
+#include "crypto.h"
 
 #define MAX_FORWARD_SIZE 1024
+#ifdef CONFIG_TIPC_CRYPTO
+#define BUF_HEADROOM ALIGN(((LL_MAX_HEADER + 48) + EHDR_MAX_SIZE), 16)
+#define BUF_TAILROOM (TIPC_AES_GCM_TAG_SIZE)
+#else
 #define BUF_HEADROOM (LL_MAX_HEADER + 48)
 #define BUF_TAILROOM 16
+#endif
 
 static unsigned int align(unsigned int i)
 {
@@ -61,7 +67,11 @@ static unsigned int align(unsigned int i)
 struct sk_buff *tipc_buf_acquire(u32 size, gfp_t gfp)
 {
 	struct sk_buff *skb;
+#ifdef CONFIG_TIPC_CRYPTO
+	unsigned int buf_size = (BUF_HEADROOM + size + BUF_TAILROOM + 3) & ~3u;
+#else
 	unsigned int buf_size = (BUF_HEADROOM + size + 3) & ~3u;
+#endif
 
 	skb = alloc_skb_fclone(buf_size, gfp);
 	if (skb) {
@@ -173,7 +183,7 @@ int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
 	}
 
 	if (fragid == LAST_FRAGMENT) {
-		TIPC_SKB_CB(head)->validated = false;
+		TIPC_SKB_CB(head)->validated = 0;
 		if (unlikely(!tipc_msg_validate(&head)))
 			goto err;
 		*buf = head;
@@ -271,6 +281,7 @@ bool tipc_msg_validate(struct sk_buff **_skb)
 
 	if (unlikely(TIPC_SKB_CB(skb)->validated))
 		return true;
+
 	if (unlikely(!pskb_may_pull(skb, MIN_H_SIZE)))
 		return false;
 
@@ -292,7 +303,7 @@ bool tipc_msg_validate(struct sk_buff **_skb)
 	if (unlikely(skb->len < msz))
 		return false;
 
-	TIPC_SKB_CB(skb)->validated = true;
+	TIPC_SKB_CB(skb)->validated = 1;
 	return true;
 }
 
diff --git a/net/tipc/msg.h b/net/tipc/msg.h
index 14697e6c995e..6d466ebdb64f 100644
--- a/net/tipc/msg.h
+++ b/net/tipc/msg.h
@@ -102,16 +102,42 @@ struct plist;
 #define TIPC_MEDIA_INFO_OFFSET	5
 
 struct tipc_skb_cb {
-	struct sk_buff *tail;
-	unsigned long nxt_retr;
-	unsigned long retr_stamp;
-	u32 bytes_read;
-	u32 orig_member;
-	u16 chain_imp;
-	u16 ackers;
-	u16 retr_cnt;
-	bool validated;
-};
+	union {
+		struct {
+			struct sk_buff *tail;
+			unsigned long nxt_retr;
+			unsigned long retr_stamp;
+			u32 bytes_read;
+			u32 orig_member;
+			u16 chain_imp;
+			u16 ackers;
+			u16 retr_cnt;
+		} __packed;
+#ifdef CONFIG_TIPC_CRYPTO
+		struct {
+			struct tipc_crypto *rx;
+			struct tipc_aead *last;
+			u8 recurs;
+		} tx_clone_ctx __packed;
+#endif
+	} __packed;
+	union {
+		struct {
+			u8 validated:1;
+#ifdef CONFIG_TIPC_CRYPTO
+			u8 encrypted:1;
+			u8 decrypted:1;
+			u8 probe:1;
+			u8 tx_clone_deferred:1;
+#endif
+		};
+		u8 flags;
+	};
+	u8 reserved;
+#ifdef CONFIG_TIPC_CRYPTO
+	void *crypto_ctx;
+#endif
+} __packed;
 
 #define TIPC_SKB_CB(__skb) ((struct tipc_skb_cb *)&((__skb)->cb[0]))
 
diff --git a/net/tipc/node.c b/net/tipc/node.c
index 43d12a630f34..d8bf2c179562 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -44,6 +44,7 @@
 #include "discover.h"
 #include "netlink.h"
 #include "trace.h"
+#include "crypto.h"
 
 #define INVALID_NODE_SIG	0x10000
 #define NODE_CLEANUP_AFTER	300000
@@ -100,6 +101,7 @@ struct tipc_bclink_entry {
  * @publ_list: list of publications
  * @rcu: rcu struct for tipc_node
  * @delete_at: indicates the time for deleting a down node
+ * @crypto_rx: RX crypto handler
  */
 struct tipc_node {
 	u32 addr;
@@ -131,6 +133,9 @@ struct tipc_node {
 	unsigned long delete_at;
 	struct net *peer_net;
 	u32 peer_hash_mix;
+#ifdef CONFIG_TIPC_CRYPTO
+	struct tipc_crypto *crypto_rx;
+#endif
 };
 
 /* Node FSM states and events:
@@ -168,7 +173,6 @@ static void tipc_node_timeout(struct timer_list *t);
 static void tipc_node_fsm_evt(struct tipc_node *n, int evt);
 static struct tipc_node *tipc_node_find(struct net *net, u32 addr);
 static struct tipc_node *tipc_node_find_by_id(struct net *net, u8 *id);
-static void tipc_node_put(struct tipc_node *node);
 static bool node_is_up(struct tipc_node *n);
 static void tipc_node_delete_from_list(struct tipc_node *node);
 
@@ -258,15 +262,41 @@ char *tipc_node_get_id_str(struct tipc_node *node)
 	return node->peer_id_string;
 }
 
+#ifdef CONFIG_TIPC_CRYPTO
+/**
+ * tipc_node_crypto_rx - Retrieve crypto RX handle from node
+ * Note: node ref counter must be held first!
+ */
+struct tipc_crypto *tipc_node_crypto_rx(struct tipc_node *__n)
+{
+	return (__n) ? __n->crypto_rx : NULL;
+}
+
+struct tipc_crypto *tipc_node_crypto_rx_by_list(struct list_head *pos)
+{
+	return container_of(pos, struct tipc_node, list)->crypto_rx;
+}
+#endif
+
+void tipc_node_free(struct rcu_head *rp)
+{
+	struct tipc_node *n = container_of(rp, struct tipc_node, rcu);
+
+#ifdef CONFIG_TIPC_CRYPTO
+	tipc_crypto_stop(&n->crypto_rx);
+#endif
+	kfree(n);
+}
+
 static void tipc_node_kref_release(struct kref *kref)
 {
 	struct tipc_node *n = container_of(kref, struct tipc_node, kref);
 
 	kfree(n->bc_entry.link);
-	kfree_rcu(n, rcu);
+	call_rcu(&n->rcu, tipc_node_free);
 }
 
-static void tipc_node_put(struct tipc_node *node)
+void tipc_node_put(struct tipc_node *node)
 {
 	kref_put(&node->kref, tipc_node_kref_release);
 }
@@ -411,9 +441,9 @@ static void tipc_node_assign_peer_net(struct tipc_node *n, u32 hash_mixes)
 	}
 }
 
-static struct tipc_node *tipc_node_create(struct net *net, u32 addr,
-					  u8 *peer_id, u16 capabilities,
-					  u32 hash_mixes, bool preliminary)
+struct tipc_node *tipc_node_create(struct net *net, u32 addr, u8 *peer_id,
+				   u16 capabilities, u32 hash_mixes,
+				   bool preliminary)
 {
 	struct tipc_net *tn = net_generic(net, tipc_net_id);
 	struct tipc_node *n, *temp_node;
@@ -474,6 +504,14 @@ update:
 		goto exit;
 	}
 	tipc_nodeid2string(n->peer_id_string, peer_id);
+#ifdef CONFIG_TIPC_CRYPTO
+	if (unlikely(tipc_crypto_start(&n->crypto_rx, net, n))) {
+		pr_warn("Failed to start crypto RX(%s)!\n", n->peer_id_string);
+		kfree(n);
+		n = NULL;
+		goto exit;
+	}
+#endif
 	n->addr = addr;
 	n->preliminary = preliminary;
 	memcpy(&n->peer_id, peer_id, 16);
@@ -725,6 +763,10 @@ static void tipc_node_timeout(struct timer_list *t)
 		return;
 	}
 
+#ifdef CONFIG_TIPC_CRYPTO
+	/* Take any crypto key related actions first */
+	tipc_crypto_timeout(n->crypto_rx);
+#endif
 	__skb_queue_head_init(&xmitq);
 
 	/* Initial node interval to value larger (10 seconds), then it will be
@@ -745,7 +787,7 @@ static void tipc_node_timeout(struct timer_list *t)
 			remains--;
 		}
 		tipc_node_read_unlock(n);
-		tipc_bearer_xmit(n->net, bearer_id, &xmitq, &le->maddr);
+		tipc_bearer_xmit(n->net, bearer_id, &xmitq, &le->maddr, n);
 		if (rc & TIPC_LINK_DOWN_EVT)
 			tipc_node_link_down(n, bearer_id, false);
 	}
@@ -777,7 +819,7 @@ static void __tipc_node_link_up(struct tipc_node *n, int bearer_id,
 	n->link_id = tipc_link_id(nl);
 
 	/* Leave room for tunnel header when returning 'mtu' to users: */
-	n->links[bearer_id].mtu = tipc_link_mtu(nl) - INT_H_SIZE;
+	n->links[bearer_id].mtu = tipc_link_mss(nl);
 
 	tipc_bearer_add_dest(n->net, bearer_id, n->addr);
 	tipc_bcast_inc_bearer_dst_cnt(n->net, bearer_id);
@@ -831,7 +873,7 @@ static void tipc_node_link_up(struct tipc_node *n, int bearer_id,
 	tipc_node_write_lock(n);
 	__tipc_node_link_up(n, bearer_id, xmitq);
 	maddr = &n->links[bearer_id].maddr;
-	tipc_bearer_xmit(n->net, bearer_id, xmitq, maddr);
+	tipc_bearer_xmit(n->net, bearer_id, xmitq, maddr, n);
 	tipc_node_write_unlock(n);
 }
 
@@ -986,7 +1028,7 @@ static void tipc_node_link_down(struct tipc_node *n, int bearer_id, bool delete)
 	if (delete)
 		tipc_mon_remove_peer(n->net, n->addr, old_bearer_id);
 	if (!skb_queue_empty(&xmitq))
-		tipc_bearer_xmit(n->net, bearer_id, &xmitq, maddr);
+		tipc_bearer_xmit(n->net, bearer_id, &xmitq, maddr, n);
 	tipc_sk_rcv(n->net, &le->inputq);
 }
 
@@ -1640,7 +1682,7 @@ int tipc_node_xmit(struct net *net, struct sk_buff_head *list,
 	if (unlikely(rc == -ENOBUFS))
 		tipc_node_link_down(n, bearer_id, false);
 	else
-		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
+		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr, n);
 
 	tipc_node_put(n);
 
@@ -1788,7 +1830,7 @@ static void tipc_node_bc_rcv(struct net *net, struct sk_buff *skb, int bearer_id
 	}
 
 	if (!skb_queue_empty(&xmitq))
-		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
+		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr, n);
 
 	if (!skb_queue_empty(&be->inputq1))
 		tipc_node_mcast_rcv(n);
@@ -1966,20 +2008,38 @@ static bool tipc_node_check_state(struct tipc_node *n, struct sk_buff *skb,
 void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
 {
 	struct sk_buff_head xmitq;
-	struct tipc_node *n;
+	struct tipc_link_entry *le;
 	struct tipc_msg *hdr;
+	struct tipc_node *n;
 	int bearer_id = b->identity;
-	struct tipc_link_entry *le;
 	u32 self = tipc_own_addr(net);
 	int usr, rc = 0;
 	u16 bc_ack;
+#ifdef CONFIG_TIPC_CRYPTO
+	struct tipc_ehdr *ehdr;
 
-	__skb_queue_head_init(&xmitq);
+	/* Check if message must be decrypted first */
+	if (TIPC_SKB_CB(skb)->decrypted || !tipc_ehdr_validate(skb))
+		goto rcv;
 
+	ehdr = (struct tipc_ehdr *)skb->data;
+	if (likely(ehdr->user != LINK_CONFIG)) {
+		n = tipc_node_find(net, ntohl(ehdr->addr));
+		if (unlikely(!n))
+			goto discard;
+	} else {
+		n = tipc_node_find_by_id(net, ehdr->id);
+	}
+	tipc_crypto_rcv(net, (n) ? n->crypto_rx : NULL, &skb, b);
+	if (!skb)
+		return;
+
+rcv:
+#endif
 	/* Ensure message is well-formed before touching the header */
-	TIPC_SKB_CB(skb)->validated = false;
 	if (unlikely(!tipc_msg_validate(&skb)))
 		goto discard;
+	__skb_queue_head_init(&xmitq);
 	hdr = buf_msg(skb);
 	usr = msg_user(hdr);
 	bc_ack = msg_bcast_ack(hdr);
@@ -2050,7 +2110,7 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
 		tipc_sk_rcv(net, &le->inputq);
 
 	if (!skb_queue_empty(&xmitq))
-		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
+		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr, n);
 
 	tipc_node_put(n);
 discard:
@@ -2081,7 +2141,7 @@ void tipc_node_apply_property(struct net *net, struct tipc_bearer *b,
 				tipc_link_set_mtu(e->link, b->mtu);
 		}
 		tipc_node_write_unlock(n);
-		tipc_bearer_xmit(net, bearer_id, &xmitq, &e->maddr);
+		tipc_bearer_xmit(net, bearer_id, &xmitq, &e->maddr, NULL);
 	}
 
 	rcu_read_unlock();
@@ -2323,7 +2383,8 @@ int tipc_nl_node_set_link(struct sk_buff *skb, struct genl_info *info)
 
 out:
 	tipc_node_read_unlock(node);
-	tipc_bearer_xmit(net, bearer_id, &xmitq, &node->links[bearer_id].maddr);
+	tipc_bearer_xmit(net, bearer_id, &xmitq, &node->links[bearer_id].maddr,
+			 NULL);
 	return res;
 }
 
diff --git a/net/tipc/node.h b/net/tipc/node.h
index 50f8838b32c2..1a15cf82cb11 100644
--- a/net/tipc/node.h
+++ b/net/tipc/node.h
@@ -76,6 +76,14 @@ void tipc_node_stop(struct net *net);
 bool tipc_node_get_id(struct net *net, u32 addr, u8 *id);
 u32 tipc_node_get_addr(struct tipc_node *node);
 char *tipc_node_get_id_str(struct tipc_node *node);
+void tipc_node_put(struct tipc_node *node);
+struct tipc_node *tipc_node_create(struct net *net, u32 addr, u8 *peer_id,
+				   u16 capabilities, u32 hash_mixes,
+				   bool preliminary);
+#ifdef CONFIG_TIPC_CRYPTO
+struct tipc_crypto *tipc_node_crypto_rx(struct tipc_node *__n);
+struct tipc_crypto *tipc_node_crypto_rx_by_list(struct list_head *pos);
+#endif
 u32 tipc_node_try_addr(struct net *net, u8 *id, u32 addr);
 void tipc_node_check_dest(struct net *net, u32 onode, u8 *peer_id128,
 			  struct tipc_bearer *bearer,
diff --git a/net/tipc/sysctl.c b/net/tipc/sysctl.c
index 6159d327db76..58ab3d6dcdce 100644
--- a/net/tipc/sysctl.c
+++ b/net/tipc/sysctl.c
@@ -35,6 +35,7 @@
 
 #include "core.h"
 #include "trace.h"
+#include "crypto.h"
 
 #include <linux/sysctl.h>
 
@@ -64,6 +65,16 @@ static struct ctl_table tipc_table[] = {
 		.mode           = 0644,
 		.proc_handler   = proc_doulongvec_minmax,
 	},
+#ifdef CONFIG_TIPC_CRYPTO
+	{
+		.procname	= "max_tfms",
+		.data		= &sysctl_tipc_max_tfms,
+		.maxlen		= sizeof(sysctl_tipc_max_tfms),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1         = SYSCTL_ONE,
+	},
+#endif
 	{}
 };
 
diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c
index 43ca5fd6574d..86aaa4d3e781 100644
--- a/net/tipc/udp_media.c
+++ b/net/tipc/udp_media.c
@@ -372,6 +372,7 @@ static int tipc_udp_recv(struct sock *sk, struct sk_buff *skb)
 		goto out;
 
 	if (b && test_bit(0, &b->up)) {
+		TIPC_SKB_CB(skb)->flags = 0;
 		tipc_rcv(sock_net(sk), skb, b);
 		return 0;
 	}