FreeBSD/Linux Kernel Cross Reference
sys/netinet/tcp_hostcache.h

     /*-
      * SPDX-License-Identifier: BSD-3-Clause
      *
      * Copyright (c) 2002 Andre Oppermann, Internet Business Solutions AG
      * All rights reserved.
      *
      * 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.
     * 3. The name of the author may not be used to endorse or promote
     *    products derived from this software without specific prior written
     *    permission.
     *
     * 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.
     *
     * $FreeBSD: releng/12.0/sys/netinet/tcp_hostcache.h 326272 2017-11-27 15:23:17Z pfg $
     */
    
    /*
     * Many thanks to jlemon for basic structure of tcp_syncache which is being
     * followed here.
     */
    
    #ifndef _NETINET_TCP_HOSTCACHE_H_
    #define _NETINET_TCP_HOSTCACHE_H_
    
    TAILQ_HEAD(hc_qhead, hc_metrics);
    
    struct hc_head {
            struct hc_qhead hch_bucket;
            u_int           hch_length;
            struct mtx      hch_mtx;
    };
    
    struct hc_metrics {
            /* housekeeping */
            TAILQ_ENTRY(hc_metrics) rmx_q;
            struct          hc_head *rmx_head; /* head of bucket tail queue */
            struct          in_addr ip4;    /* IP address */
            struct          in6_addr ip6;   /* IP6 address */
            uint32_t        ip6_zoneid;     /* IPv6 scope zone id */
            /* endpoint specific values for tcp */
            uint32_t        rmx_mtu;        /* MTU for this path */
            uint32_t        rmx_ssthresh;   /* outbound gateway buffer limit */
            uint32_t        rmx_rtt;        /* estimated round trip time */
            uint32_t        rmx_rttvar;     /* estimated rtt variance */
            uint32_t        rmx_cwnd;       /* congestion window */
            uint32_t        rmx_sendpipe;   /* outbound delay-bandwidth product */
            uint32_t        rmx_recvpipe;   /* inbound delay-bandwidth product */
            /* TCP hostcache internal data */
            int             rmx_expire;     /* lifetime for object */
            u_long          rmx_hits;       /* number of hits */
            u_long          rmx_updates;    /* number of updates */
    };
    
    struct tcp_hostcache {
            struct  hc_head *hashbase;
            uma_zone_t zone;
            u_int   hashsize;
            u_int   hashmask;
            u_int   bucket_limit;
            u_int   cache_count;
            u_int   cache_limit;
            int     expire;
            int     prune;
            int     purgeall;
    };
    
    #endif /* !_NETINET_TCP_HOSTCACHE_H_*/

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