Line data    Source code

       1             : /*
       2             :  * include/net/tipc.h: Include file for TIPC message header routines
       3             :  *
       4             :  * Copyright (c) 2017 Ericsson AB
       5             :  * All rights reserved.
       6             :  *
       7             :  * Redistribution and use in source and binary forms, with or without
       8             :  * modification, are permitted provided that the following conditions are met:
       9             :  *
      10             :  * 1. Redistributions of source code must retain the above copyright
      11             :  *    notice, this list of conditions and the following disclaimer.
      12             :  * 2. Redistributions in binary form must reproduce the above copyright
      13             :  *    notice, this list of conditions and the following disclaimer in the
      14             :  *    documentation and/or other materials provided with the distribution.
      15             :  * 3. Neither the names of the copyright holders nor the names of its
      16             :  *    contributors may be used to endorse or promote products derived from
      17             :  *    this software without specific prior written permission.
      18             :  *
      19             :  * Alternatively, this software may be distributed under the terms of the
      20             :  * GNU General Public License ("GPL") version 2 as published by the Free
      21             :  * Software Foundation.
      22             :  *
      23             :  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
      24             :  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
      25             :  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
      26             :  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
      27             :  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
      28             :  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
      29             :  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
      30             :  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
      31             :  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
      32             :  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
      33             :  * POSSIBILITY OF SUCH DAMAGE.
      34             :  */
      35             : 
      36             : #ifndef _TIPC_HDR_H
      37             : #define _TIPC_HDR_H
      38             : 
      39             : #include <linux/random.h>
      40             : 
      41             : #define KEEPALIVE_MSG_MASK 0x0e080000  /* LINK_PROTOCOL + MSG_IS_KEEPALIVE */
      42             : 
      43             : struct tipc_basic_hdr {
      44             :         __be32 w[4];
      45             : };
      46             : 
      47           0 : static inline __be32 tipc_hdr_rps_key(struct tipc_basic_hdr *hdr)
      48             : {
      49           0 :         u32 w0 = ntohl(hdr->w[0]);
      50           0 :         bool keepalive_msg = (w0 & KEEPALIVE_MSG_MASK) == KEEPALIVE_MSG_MASK;
      51           0 :         __be32 key;
      52             : 
      53             :         /* Return source node identity as key */
      54           0 :         if (likely(!keepalive_msg))
      55           0 :                 return hdr->w[3];
      56             : 
      57             :         /* Spread PROBE/PROBE_REPLY messages across the cores */
      58           0 :         get_random_bytes(&key, sizeof(key));
      59           0 :         return key;
      60             : }
      61             : 
      62             : #endif