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4dde4205e1
If an attempt to add a route fails because an "ARP table" entry is in the way, remove the ARP entry and retry the add. Reviewed by: nate
370 lines
10 KiB
C
370 lines
10 KiB
C
/*
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* Copyright 1994, 1995 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_rmx.c,v 1.22 1995/12/19 20:46:13 wollman Exp $
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*/
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/*
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* This code does two things necessary for the enhanced TCP metrics to
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* function in a useful manner:
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* 1) It marks all non-host routes as `cloning', thus ensuring that
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* every actual reference to such a route actually gets turned
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* into a reference to a host route to the specific destination
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* requested.
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* 2) When such routes lose all their references, it arranges for them
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* to be deleted in some random collection of circumstances, so that
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* a large quantity of stale routing data is not kept in kernel memory
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* indefinitely. See in_rtqtimo() below for the exact mechanism.
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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/kernel.h>
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#include <sys/sysctl.h>
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#include <sys/queue.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/mbuf.h>
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#include <sys/syslog.h>
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#include <net/if.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/in_var.h>
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#include <netinet/ip.h>
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#include <netinet/ip_var.h>
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#include <netinet/tcp.h>
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#include <netinet/tcp_seq.h>
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#include <netinet/tcp_timer.h>
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#include <netinet/tcp_var.h>
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#if 0
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#include <netinet/tcpip.h>
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#endif
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extern int in_inithead __P((void **head, int off));
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#define RTPRF_OURS RTF_PROTO3 /* set on routes we manage */
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/*
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* Do what we need to do when inserting a route.
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*/
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static struct radix_node *
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in_addroute(void *v_arg, void *n_arg, struct radix_node_head *head,
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struct radix_node *treenodes)
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{
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struct rtentry *rt = (struct rtentry *)treenodes;
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struct sockaddr_in *sin = (struct sockaddr_in *)rt_key(rt);
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struct radix_node *ret;
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/*
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* For IP, all unicast non-host routes are automatically cloning.
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*/
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if(!(rt->rt_flags & (RTF_HOST | RTF_CLONING))) {
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if(!IN_MULTICAST(ntohl(sin->sin_addr.s_addr))) {
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rt->rt_flags |= RTF_PRCLONING;
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}
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}
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/*
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* We also specify a send and receive pipe size for every
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* route added, to help TCP a bit. TCP doesn't actually
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* want a true pipe size, which would be prohibitive in memory
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* costs and is hard to compute anyway; it simply uses these
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* values to size its buffers. So, we fill them in with the
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* same values that TCP would have used anyway, and allow the
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* installing program or the link layer to override these values
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* as it sees fit. This will hopefully allow TCP more
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* opportunities to save its ssthresh value.
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*/
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if (!rt->rt_rmx.rmx_sendpipe && !(rt->rt_rmx.rmx_locks & RTV_SPIPE))
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rt->rt_rmx.rmx_sendpipe = tcp_sendspace;
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if (!rt->rt_rmx.rmx_recvpipe && !(rt->rt_rmx.rmx_locks & RTV_RPIPE))
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rt->rt_rmx.rmx_recvpipe = tcp_recvspace;
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#if 0
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/*
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* Finally, set an MTU, again duplicating logic in TCP.
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* The in_localaddr() business will go away when we have
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* proper PMTU discovery.
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*/
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#endif
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if (!rt->rt_rmx.rmx_mtu && !(rt->rt_rmx.rmx_locks & RTV_MTU)
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&& rt->rt_ifp)
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#if 0
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rt->rt_rmx.rmx_mtu = (in_localaddr(sin->sin_addr)
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? rt->rt_ifp->if_mtu
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: tcp_mssdflt + sizeof(struct tcpiphdr));
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#else
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rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
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#endif
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ret = rn_addroute(v_arg, n_arg, head, treenodes);
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if (ret == NULL && rt->rt_flags & RTF_HOST) {
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struct rtentry *rt2;
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/*
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* We are trying to add a host route, but can't.
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* Find out if it is because of an
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* ARP entry and delete it if so.
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*/
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rt2 = rtalloc1((struct sockaddr *)sin, 0,
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RTF_CLONING | RTF_PRCLONING);
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if (rt2) {
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if (rt2->rt_flags & RTF_LLINFO &&
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rt2->rt_flags & RTF_HOST &&
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rt2->rt_gateway &&
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rt2->rt_gateway->sa_family == AF_LINK) {
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rtrequest(RTM_DELETE,
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(struct sockaddr *)rt_key(rt2),
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rt2->rt_gateway,
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rt_mask(rt2), rt2->rt_flags, 0);
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ret = rn_addroute(v_arg, n_arg, head,
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treenodes);
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}
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RTFREE(rt2);
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}
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}
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return ret;
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}
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/*
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* This code is the inverse of in_clsroute: on first reference, if we
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* were managing the route, stop doing so and set the expiration timer
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* back off again.
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*/
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static struct radix_node *
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in_matroute(void *v_arg, struct radix_node_head *head)
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{
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struct radix_node *rn = rn_match(v_arg, head);
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struct rtentry *rt = (struct rtentry *)rn;
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if(rt && rt->rt_refcnt == 0) { /* this is first reference */
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if(rt->rt_flags & RTPRF_OURS) {
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rt->rt_flags &= ~RTPRF_OURS;
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rt->rt_rmx.rmx_expire = 0;
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}
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}
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return rn;
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}
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static int rtq_reallyold = 60*60;
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/* one hour is ``really old'' */
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SYSCTL_INT(_net_inet_ip, IPCTL_RTEXPIRE, rtexpire,
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CTLFLAG_RW, &rtq_reallyold , 0, "");
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static int rtq_minreallyold = 10;
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/* never automatically crank down to less */
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SYSCTL_INT(_net_inet_ip, IPCTL_RTMINEXPIRE, rtminexpire,
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CTLFLAG_RW, &rtq_minreallyold , 0, "");
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static int rtq_toomany = 128;
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/* 128 cached routes is ``too many'' */
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SYSCTL_INT(_net_inet_ip, IPCTL_RTMAXCACHE, rtmaxcache,
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CTLFLAG_RW, &rtq_toomany , 0, "");
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/*
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* On last reference drop, mark the route as belong to us so that it can be
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* timed out.
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*/
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static void
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in_clsroute(struct radix_node *rn, struct radix_node_head *head)
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{
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struct rtentry *rt = (struct rtentry *)rn;
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if(!(rt->rt_flags & RTF_UP))
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return; /* prophylactic measures */
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if((rt->rt_flags & (RTF_LLINFO | RTF_HOST)) != RTF_HOST)
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return;
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if((rt->rt_flags & (RTF_WASCLONED | RTPRF_OURS))
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!= RTF_WASCLONED)
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return;
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/*
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* As requested by David Greenman:
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* If rtq_reallyold is 0, just delete the route without
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* waiting for a timeout cycle to kill it.
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*/
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if(rtq_reallyold != 0) {
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rt->rt_flags |= RTPRF_OURS;
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rt->rt_rmx.rmx_expire = time.tv_sec + rtq_reallyold;
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} else {
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rtrequest(RTM_DELETE,
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(struct sockaddr *)rt_key(rt),
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rt->rt_gateway, rt_mask(rt),
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rt->rt_flags, 0);
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}
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}
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struct rtqk_arg {
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struct radix_node_head *rnh;
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int draining;
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int killed;
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int found;
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int updating;
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time_t nextstop;
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};
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/*
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* Get rid of old routes. When draining, this deletes everything, even when
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* the timeout is not expired yet. When updating, this makes sure that
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* nothing has a timeout longer than the current value of rtq_reallyold.
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*/
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static int
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in_rtqkill(struct radix_node *rn, void *rock)
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{
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struct rtqk_arg *ap = rock;
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struct rtentry *rt = (struct rtentry *)rn;
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int err;
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if(rt->rt_flags & RTPRF_OURS) {
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ap->found++;
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if(ap->draining || rt->rt_rmx.rmx_expire <= time.tv_sec) {
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if(rt->rt_refcnt > 0)
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panic("rtqkill route really not free");
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err = rtrequest(RTM_DELETE,
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(struct sockaddr *)rt_key(rt),
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rt->rt_gateway, rt_mask(rt),
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rt->rt_flags, 0);
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if(err) {
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log(LOG_WARNING, "in_rtqkill: error %d\n", err);
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} else {
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ap->killed++;
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}
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} else {
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if(ap->updating
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&& (rt->rt_rmx.rmx_expire - time.tv_sec
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> rtq_reallyold)) {
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rt->rt_rmx.rmx_expire = time.tv_sec
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+ rtq_reallyold;
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}
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ap->nextstop = lmin(ap->nextstop,
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rt->rt_rmx.rmx_expire);
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}
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}
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return 0;
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}
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#define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */
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static int rtq_timeout = RTQ_TIMEOUT;
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static void
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in_rtqtimo(void *rock)
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{
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struct radix_node_head *rnh = rock;
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struct rtqk_arg arg;
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struct timeval atv;
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static time_t last_adjusted_timeout = 0;
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int s;
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arg.found = arg.killed = 0;
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arg.rnh = rnh;
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arg.nextstop = time.tv_sec + rtq_timeout;
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arg.draining = arg.updating = 0;
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s = splnet();
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rnh->rnh_walktree(rnh, in_rtqkill, &arg);
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splx(s);
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/*
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* Attempt to be somewhat dynamic about this:
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* If there are ``too many'' routes sitting around taking up space,
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* then crank down the timeout, and see if we can't make some more
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* go away. However, we make sure that we will never adjust more
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* than once in rtq_timeout seconds, to keep from cranking down too
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* hard.
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*/
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if((arg.found - arg.killed > rtq_toomany)
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&& (time.tv_sec - last_adjusted_timeout >= rtq_timeout)
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&& rtq_reallyold > rtq_minreallyold) {
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rtq_reallyold = 2*rtq_reallyold / 3;
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if(rtq_reallyold < rtq_minreallyold) {
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rtq_reallyold = rtq_minreallyold;
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}
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last_adjusted_timeout = time.tv_sec;
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log(LOG_DEBUG, "in_rtqtimo: adjusted rtq_reallyold to %d\n",
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rtq_reallyold);
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arg.found = arg.killed = 0;
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arg.updating = 1;
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s = splnet();
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rnh->rnh_walktree(rnh, in_rtqkill, &arg);
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splx(s);
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}
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atv.tv_usec = 0;
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atv.tv_sec = arg.nextstop;
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timeout(in_rtqtimo, rock, hzto(&atv));
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}
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void
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in_rtqdrain(void)
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{
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struct radix_node_head *rnh = rt_tables[AF_INET];
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struct rtqk_arg arg;
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int s;
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arg.found = arg.killed = 0;
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arg.rnh = rnh;
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arg.nextstop = 0;
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arg.draining = 1;
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arg.updating = 0;
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s = splnet();
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rnh->rnh_walktree(rnh, in_rtqkill, &arg);
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splx(s);
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}
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/*
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* Initialize our routing tree.
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*/
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int
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in_inithead(void **head, int off)
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{
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struct radix_node_head *rnh;
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if(!rn_inithead(head, off))
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return 0;
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if(head != (void **)&rt_tables[AF_INET]) /* BOGUS! */
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return 1; /* only do this for the real routing table */
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rnh = *head;
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rnh->rnh_addaddr = in_addroute;
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rnh->rnh_matchaddr = in_matroute;
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rnh->rnh_close = in_clsroute;
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in_rtqtimo(rnh); /* kick off timeout first time */
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return 1;
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}
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