LXR linux/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
  43struct tipc_basic_hdr {
  44        __be32 w[4];
  45};
  46
  47static 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
  63