FreeBSD/Linux Kernel Cross Reference
sys/net/route/route_temporal.c

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2020 Alexander V. Chernikov
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    /*
     * This file contains code responsible for expiring temporal routes
     * (typically, redirect-originated) from the route tables.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/socket.h>
    #include <sys/kernel.h>
    #include <sys/lock.h>
    #include <sys/ck.h>
    #include <sys/rmlock.h>
    #include <sys/callout.h>
    
    #include <net/if.h>
    #include <net/route.h>
    #include <net/route/route_ctl.h>
    #include <net/route/route_var.h>
    #include <net/vnet.h>
    
    /*
     * Callback returning 1 for the expired routes.
     * Updates time of the next nearest route expiration as a side effect.
     */
    static int
    expire_route(const struct rtentry *rt, const struct nhop_object *nh, void *arg)
    {
            uint32_t nh_expire = nhop_get_expire(nh);
            time_t *next_callout;
    
            if (nh_expire == 0)
                    return (0);
    
            if (nh_expire <= time_uptime)
                    return (1);
    
            next_callout = (time_t *)arg;
    
            /*
             * Update next_callout to determine the next ts to
             * run the callback at.
             */
            if (*next_callout == 0 || *next_callout > nh_expire)
                    *next_callout = nh_expire;
    
            return (0);
    }
    
    /*
     * Per-rnh callout function traversing the tree and deleting
     * expired routes. Calculates next callout run by looking at
     * the nh_expire time for the remaining temporal routes.
     */
    static void
    expire_callout(void *arg)
    {
            struct rib_head *rnh;
            time_t next_expire;
            int seconds;
    
            rnh = (struct rib_head *)arg;
    
            CURVNET_SET(rnh->rib_vnet);
            next_expire = 0;
    
            rib_walk_del(rnh->rib_fibnum, rnh->rib_family, expire_route,
                (void *)&next_expire, 1);
    
            RIB_WLOCK(rnh);
           if (next_expire > 0) {
                   seconds = (next_expire - time_uptime);
                   if (seconds < 0)
                           seconds = 0;
                   callout_reset_sbt(&rnh->expire_callout, SBT_1S * seconds,
                       SBT_1MS * 500, expire_callout, rnh, 0);
                   rnh->next_expire = next_expire;
           } else {
                   /*
                    * Before resetting next_expire, check that tmproutes_update()
                    * has not kicked in and scheduled another invocation.
                    */
                   if (callout_pending(&rnh->expire_callout) == 0)
                           rnh->next_expire = 0;
           }
           RIB_WUNLOCK(rnh);
           CURVNET_RESTORE();
   }
   
   /*
    * Function responsible for updating the time of the next calllout
    * w.r.t. new temporal routes insertion.
    *
    * Called by the routing code upon adding new temporal route
    * to the tree. RIB_WLOCK must be held.
    */
   void
   tmproutes_update(struct rib_head *rnh, struct rtentry *rt, struct nhop_object *nh)
   {
           int seconds;
           uint32_t nh_expire = nhop_get_expire(nh);
   
           RIB_WLOCK_ASSERT(rnh);
   
           if (rnh->next_expire == 0 || rnh->next_expire > nh_expire) {
                   /*
                    * Callback is not scheduled, is executing,
                    * or is scheduled for a later time than we need.
                    *
                    * Schedule the one for the current @rt expiration time.
                    */
                   seconds = (nh_expire - time_uptime);
                   if (seconds < 0)
                           seconds = 0;
                   callout_reset_sbt(&rnh->expire_callout, SBT_1S * seconds,
                       SBT_1MS * 500, expire_callout, rnh, 0);
   
                   rnh->next_expire = nh_expire;
           }
   }
   
   void
   tmproutes_init(struct rib_head *rh)
   {
   
           callout_init(&rh->expire_callout, 1);
   }
   
   void
   tmproutes_destroy(struct rib_head *rh)
   {
   
           callout_drain(&rh->expire_callout);
   }

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