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>
		
	
			
		
			
				
	
	
		
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			168 lines
		
	
	
		
			6.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* SPDX-License-Identifier: GPL-2.0 */
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/**
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 * net/tipc/crypto.h: Include file for TIPC crypto
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 *
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 * Copyright (c) 2019, Ericsson AB
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions are met:
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 *
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. Neither the names of the copyright holders nor the names of its
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 *    contributors may be used to endorse or promote products derived from
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 *    this software without specific prior written permission.
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 *
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 * Alternatively, this software may be distributed under the terms of the
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 * GNU General Public License ("GPL") version 2 as published by the Free
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 * Software Foundation.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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 * POSSIBILITY OF SUCH DAMAGE.
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 */
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#ifdef CONFIG_TIPC_CRYPTO
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#ifndef _TIPC_CRYPTO_H
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#define _TIPC_CRYPTO_H
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#include "core.h"
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#include "node.h"
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#include "msg.h"
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#include "bearer.h"
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#define TIPC_EVERSION			7
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/* AEAD aes(gcm) */
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#define TIPC_AES_GCM_KEY_SIZE_128	16
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#define TIPC_AES_GCM_KEY_SIZE_192	24
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#define TIPC_AES_GCM_KEY_SIZE_256	32
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#define TIPC_AES_GCM_SALT_SIZE		4
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#define TIPC_AES_GCM_IV_SIZE		12
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#define TIPC_AES_GCM_TAG_SIZE		16
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/**
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 * TIPC crypto modes:
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 * - CLUSTER_KEY:
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 *	One single key is used for both TX & RX in all nodes in the cluster.
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 * - PER_NODE_KEY:
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 *	Each nodes in the cluster has one TX key, for RX a node needs to know
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 *	its peers' TX key for the decryption of messages from those nodes.
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 */
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enum {
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	CLUSTER_KEY = 1,
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	PER_NODE_KEY = (1 << 1),
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};
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extern int sysctl_tipc_max_tfms __read_mostly;
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/**
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 * TIPC encryption message format:
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 *
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 *     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
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 *     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
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 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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 * w0:|Ver=7| User  |D|TX |RX |K|                 Rsvd                |
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 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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 * w1:|                             Seqno                             |
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 * w2:|                           (8 octets)                          |
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 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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 * w3:\                            Prevnode                           \
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 *    /                        (4 or 16 octets)                       /
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 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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 *    \                                                               \
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 *    /       Encrypted complete TIPC V2 header and user data         /
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 *    \                                                               \
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 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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 *    |                                                               |
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 *    |                             AuthTag                           |
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 *    |                           (16 octets)                         |
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 *    |                                                               |
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 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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 *
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 * Word0:
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 *	Ver	: = 7 i.e. TIPC encryption message version
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 *	User	: = 7 (for LINK_PROTOCOL); = 13 (for LINK_CONFIG) or = 0
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 *	D	: The destined bit i.e. the message's destination node is
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 *	          "known" or not at the message encryption
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 *	TX	: TX key used for the message encryption
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 *	RX	: Currently RX active key corresponding to the destination
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 *	          node's TX key (when the "D" bit is set)
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 *	K	: Keep-alive bit (for RPS, LINK_PROTOCOL/STATE_MSG only)
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 *	Rsvd	: Reserved bit, field
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 * Word1-2:
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 *	Seqno	: The 64-bit sequence number of the encrypted message, also
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 *		  part of the nonce used for the message encryption/decryption
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 * Word3-:
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 *	Prevnode: The source node address, or ID in case LINK_CONFIG only
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 *	AuthTag	: The authentication tag for the message integrity checking
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 *		  generated by the message encryption
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 */
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struct tipc_ehdr {
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	union {
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		struct {
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#if defined(__LITTLE_ENDIAN_BITFIELD)
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			__u8	destined:1,
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				user:4,
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				version:3;
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			__u8	reserved_1:3,
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				keepalive:1,
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				rx_key_active:2,
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				tx_key:2;
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#elif defined(__BIG_ENDIAN_BITFIELD)
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			__u8	version:3,
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				user:4,
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				destined:1;
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			__u8	tx_key:2,
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				rx_key_active:2,
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				keepalive:1,
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				reserved_1:3;
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#else
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#error  "Please fix <asm/byteorder.h>"
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#endif
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			__be16	reserved_2;
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		} __packed;
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		__be32 w0;
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	};
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	__be64 seqno;
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	union {
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		__be32 addr;
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		__u8 id[NODE_ID_LEN]; /* For a LINK_CONFIG message only! */
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	};
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#define EHDR_SIZE	(offsetof(struct tipc_ehdr, addr) + sizeof(__be32))
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#define EHDR_CFG_SIZE	(sizeof(struct tipc_ehdr))
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#define EHDR_MIN_SIZE	(EHDR_SIZE)
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#define EHDR_MAX_SIZE	(EHDR_CFG_SIZE)
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#define EMSG_OVERHEAD	(EHDR_SIZE + TIPC_AES_GCM_TAG_SIZE)
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} __packed;
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int tipc_crypto_start(struct tipc_crypto **crypto, struct net *net,
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		      struct tipc_node *node);
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void tipc_crypto_stop(struct tipc_crypto **crypto);
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void tipc_crypto_timeout(struct tipc_crypto *rx);
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int tipc_crypto_xmit(struct net *net, struct sk_buff **skb,
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		     struct tipc_bearer *b, struct tipc_media_addr *dst,
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		     struct tipc_node *__dnode);
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int tipc_crypto_rcv(struct net *net, struct tipc_crypto *rx,
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		    struct sk_buff **skb, struct tipc_bearer *b);
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int tipc_crypto_key_init(struct tipc_crypto *c, struct tipc_aead_key *ukey,
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			 u8 mode);
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void tipc_crypto_key_flush(struct tipc_crypto *c);
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int tipc_aead_key_validate(struct tipc_aead_key *ukey);
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bool tipc_ehdr_validate(struct sk_buff *skb);
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#endif /* _TIPC_CRYPTO_H */
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#endif
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