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Rekeying is required for security since a key is less secure when using for a long time. Also, key will be detached when its nonce value (or seqno ...) is exhausted. We now make the rekeying process automatic and configurable by user. Basically, TIPC will at a specific interval generate a new key by using the kernel 'Random Number Generator' cipher, then attach it as the node TX key and securely distribute to others in the cluster as RX keys (- the key exchange). The automatic key switching will then take over, and make the new key active shortly. Afterwards, the traffic from this node will be encrypted with the new session key. The same can happen in peer nodes but not necessarily at the same time. For simplicity, the automatically generated key will be initiated as a per node key. It is not too hard to also support a cluster key rekeying (e.g. a given node will generate a unique cluster key and update to the others in the cluster...), but that doesn't bring much benefit, while a per-node key is even more secure. We also enable user to force a rekeying or change the rekeying interval via netlink, the new 'set key' command option: 'TIPC_NLA_NODE_REKEYING' is added for these purposes as follows: - A value >= 1 will be set as the rekeying interval (in minutes); - A value of 0 will disable the rekeying; - A value of 'TIPC_REKEYING_NOW' (~0) will force an immediate rekeying; The default rekeying interval is (60 * 24) minutes i.e. done every day. There isn't any restriction for the value but user shouldn't set it too small or too large which results in an "ineffective" rekeying (thats ok for testing though). Acked-by: Jon Maloy <jmaloy@redhat.com> Signed-off-by: Tuong Lien <tuong.t.lien@dektech.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
200 lines
7.3 KiB
C
200 lines
7.3 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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extern int sysctl_tipc_key_exchange_enabled __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|M|N| 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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* M : Bit indicates if sender has master key
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* N : Bit indicates if sender has no RX keys corresponding to the
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* receiver's TX (when the "D" bit is set)
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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_1:1,
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rx_nokey:1,
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master_key:1,
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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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master_key:1,
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rx_nokey:1,
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reserved_1:1;
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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, bool master_key);
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void tipc_crypto_key_flush(struct tipc_crypto *c);
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int tipc_crypto_key_distr(struct tipc_crypto *tx, u8 key,
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struct tipc_node *dest);
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void tipc_crypto_msg_rcv(struct net *net, struct sk_buff *skb);
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void tipc_crypto_rekeying_sched(struct tipc_crypto *tx, bool changed,
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u32 new_intv);
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int tipc_aead_key_validate(struct tipc_aead_key *ukey, struct genl_info *info);
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bool tipc_ehdr_validate(struct sk_buff *skb);
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static inline u32 msg_key_gen(struct tipc_msg *m)
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{
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return msg_bits(m, 4, 16, 0xffff);
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}
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static inline void msg_set_key_gen(struct tipc_msg *m, u32 gen)
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{
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msg_set_bits(m, 4, 16, 0xffff, gen);
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}
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static inline u32 msg_key_mode(struct tipc_msg *m)
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{
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return msg_bits(m, 4, 0, 0xf);
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}
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static inline void msg_set_key_mode(struct tipc_msg *m, u32 mode)
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{
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msg_set_bits(m, 4, 0, 0xf, mode);
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}
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#endif /* _TIPC_CRYPTO_H */
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#endif
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