158 lines
4.5 KiB
C
158 lines
4.5 KiB
C
/*
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* Copyright 1997 Massachusetts Institute of Technology
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*
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* Permission to use, copy, modify, and distribute this software and
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* its documentation for any purpose and without fee is hereby
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* granted, provided that both the above copyright notice and this
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* permission notice appear in all copies, that both the above
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* copyright notice and this permission notice appear in all
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* supporting documentation, and that the name of M.I.T. not be used
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* in advertising or publicity pertaining to distribution of the
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* software without specific, written prior permission. M.I.T. makes
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* no representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied
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* warranty.
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*
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* THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS
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* ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
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* SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: in_hostcache.c,v 1.1 1997/06/18 01:24:28 wollman Exp $
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <net/hostcache.h>
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#include <net/if.h>
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#include <net/if_var.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/in_hostcache.h>
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#include <netinet/tcp.h>
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#include <netinet/tcp_timer.h>
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#include <netinet/tcp_var.h>
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/*
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* Manage the IP per-host cache (really a thin veneer over the generic
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* per-host cache code).
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*/
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/* Look up an entry -- can be called from interrupt context. */
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struct in_hcentry *
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inhc_lookup(struct sockaddr_in *sin)
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{
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struct hcentry *hc;
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hc = hc_get((struct sockaddr *)sin);
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return ((struct in_hcentry *)hc);
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}
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/* Look up and possibly create an entry -- must be called from user mode. */
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struct in_hcentry *
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inhc_alloc(struct sockaddr_in *sin)
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{
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struct in_hcentry *inhc;
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struct rtentry *rt;
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int error;
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/* xxx mutual exclusion for smp */
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inhc = inhc_lookup(sin);
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if (inhc != 0)
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return inhc;
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rt = rtalloc1(inhc->inhc_hc.hc_host, 1, 0);
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if (rt == 0)
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return 0;
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MALLOC(inhc, struct in_hcentry *, sizeof *inhc, M_HOSTCACHE, M_WAITOK);
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bzero(inhc, sizeof *inhc);
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inhc->inhc_hc.hc_host = dup_sockaddr((struct sockaddr *)sin, 1);
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if (in_broadcast(sin->sin_addr, rt->rt_ifp))
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inhc->inhc_flags |= INHC_BROADCAST;
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else if (((struct sockaddr_in *)rt->rt_ifa->ifa_addr)->sin_addr.s_addr
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== sin->sin_addr.s_addr)
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inhc->inhc_flags |= INHC_LOCAL;
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else if (IN_MULTICAST(ntohl(sin->sin_addr.s_addr)))
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inhc->inhc_flags |= INHC_MULTICAST;
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inhc->inhc_pmtu = rt->rt_rmx.rmx_mtu;
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inhc->inhc_recvpipe = rt->rt_rmx.rmx_recvpipe;
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inhc->inhc_sendpipe = rt->rt_rmx.rmx_sendpipe;
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inhc->inhc_ssthresh = rt->rt_rmx.rmx_ssthresh;
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if (rt->rt_rmx.rmx_locks & RTV_RTT)
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inhc->inhc_rttmin = rt->rt_rmx.rmx_rtt
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/ (RTM_RTTUNIT / TCP_RTT_SCALE);
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inhc->inhc_hc.hc_rt = rt;
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error = hc_insert(&inhc->inhc_hc);
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if (error != 0) {
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RTFREE(rt);
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FREE(inhc, M_HOSTCACHE);
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return 0;
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}
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/*
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* We don't return the structure directly because hc_get() needs
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* to be allowed to do its own processing.
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*/
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return (inhc_lookup(sin));
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}
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/*
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* This is Van Jacobson's hash function for IPv4 addresses.
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* It is designed to work with a power-of-two-sized hash table.
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*/
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static u_long
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inhc_hash(struct sockaddr *sa, u_long nbuckets)
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{
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u_long ip;
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ip = ((struct sockaddr_in *)sa)->sin_addr.s_addr;
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return ((ip ^ (ip >> 23) ^ (ip >> 17)) & ~(nbuckets - 1));
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}
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/*
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* We don't need to do any special work... if there are no references,
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* as the caller has already ensured, then it's OK to kill.
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*/
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static int
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inhc_delete(struct hcentry *hc)
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{
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return 0;
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}
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/*
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* Return the next increment for the number of buckets in the hash table.
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* Zero means ``do not bump''.
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*/
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static u_long
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inhc_bump(u_long oldsize)
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{
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if (oldsize < 512)
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return (oldsize << 1);
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return 0;
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}
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static struct hccallback inhc_cb = {
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inhc_hash, inhc_delete, inhc_bump
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};
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int
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inhc_init(void)
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{
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return (hc_init(AF_INET, &inhc_cb, 128, 0));
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}
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