include/net/tipc.h

   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 static inline __be32 tipc_hdr_rps_key(struct tipc_basic_hdr *hdr)
  48 {
  49         u32 w0 = ntohl(hdr->w[0]);
  50         bool keepalive_msg = (w0 & KEEPALIVE_MSG_MASK) == KEEPALIVE_MSG_MASK;
  51         __be32 key;
  52
  53         /* Return source node identity as key */
  54         if (likely(!keepalive_msg))
  55                 return hdr->w[3];
  56
  57         /* Spread PROBE/PROBE_REPLY messages across the cores */
  58         get_random_bytes(&key, sizeof(key));
  59         return key;
  60 }
  61
  62 #endif