/* * Copyright 1994, 1995 Massachusetts Institute of Technology * * Permission to use, copy, modify, and distribute this software and * its documentation for any purpose and without fee is hereby * granted, provided that both the above copyright notice and this * permission notice appear in all copies, that both the above * copyright notice and this permission notice appear in all * supporting documentation, and that the name of M.I.T. not be used * in advertising or publicity pertaining to distribution of the * software without specific, written prior permission. M.I.T. makes * no representations about the suitability of this software for any * purpose. It is provided "as is" without express or implied * warranty. * * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT * SHALL M.I.T. 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. * * $Id: in_rmx.c,v 1.16 1995/09/18 15:51:32 wollman Exp $ */ /* * This code does two things necessary for the enhanced TCP metrics to * function in a useful manner: * 1) It marks all non-host routes as `cloning', thus ensuring that * every actual reference to such a route actually gets turned * into a reference to a host route to the specific destination * requested. * 2) When such routes lose all their references, it arranges for them * to be deleted in some random collection of circumstances, so that * a large quantity of stale routing data is not kept in kernel memory * indefinitely. See in_rtqtimo() below for the exact mechanism. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifndef MTUDISC #include #endif /* not MTUDISC */ #define RTPRF_OURS RTF_PROTO3 /* set on routes we manage */ /* * Do what we need to do when inserting a route. */ static struct radix_node * in_addroute(void *v_arg, void *n_arg, struct radix_node_head *head, struct radix_node *treenodes) { struct rtentry *rt = (struct rtentry *)treenodes; struct sockaddr_in *sin = (struct sockaddr_in *)rt_key(rt); /* * For IP, all unicast non-host routes are automatically cloning. */ if(!(rt->rt_flags & (RTF_HOST | RTF_CLONING))) { if(!IN_MULTICAST(ntohl(sin->sin_addr.s_addr))) { rt->rt_flags |= RTF_PRCLONING; } } /* * We also specify a send and receive pipe size for every * route added, to help TCP a bit. TCP doesn't actually * want a true pipe size, which would be prohibitive in memory * costs and is hard to compute anyway; it simply uses these * values to size its buffers. So, we fill them in with the * same values that TCP would have used anyway, and allow the * installing program or the link layer to override these values * as it sees fit. This will hopefully allow TCP more * opportunities to save its ssthresh value. */ if (!rt->rt_rmx.rmx_sendpipe && !(rt->rt_rmx.rmx_locks & RTV_SPIPE)) rt->rt_rmx.rmx_sendpipe = tcp_sendspace; if (!rt->rt_rmx.rmx_recvpipe && !(rt->rt_rmx.rmx_locks & RTV_RPIPE)) rt->rt_rmx.rmx_recvpipe = tcp_recvspace; #ifndef MTUDISC /* * Finally, set an MTU, again duplicating logic in TCP. * The in_localaddr() business will go away when we have * proper PMTU discovery. */ #endif /* not MTUDISC */ if (!rt->rt_rmx.rmx_mtu && !(rt->rt_rmx.rmx_locks & RTV_MTU) && rt->rt_ifp) #ifndef MTUDISC rt->rt_rmx.rmx_mtu = (in_localaddr(sin->sin_addr) ? rt->rt_ifp->if_mtu : tcp_mssdflt + sizeof(struct tcpiphdr)); #else /* MTUDISC */ rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; #endif /* MTUDISC */ return rn_addroute(v_arg, n_arg, head, treenodes); } /* * This code is the inverse of in_clsroute: on first reference, if we * were managing the route, stop doing so and set the expiration timer * back off again. */ static struct radix_node * in_matroute(void *v_arg, struct radix_node_head *head) { struct radix_node *rn = rn_match(v_arg, head); struct rtentry *rt = (struct rtentry *)rn; if(rt && rt->rt_refcnt == 0) { /* this is first reference */ if(rt->rt_flags & RTPRF_OURS) { rt->rt_flags &= ~RTPRF_OURS; rt->rt_rmx.rmx_expire = 0; } } return rn; } /* MIB variables: net.inet.ip.{rtexpire,rtmaxcache,rtminexpire}. */ int rtq_reallyold = 60*60; /* one hour is ``really old'' */ int rtq_toomany = 128; /* 128 cached routes is ``too many'' */ int rtq_minreallyold = 10; /* never automatically crank down to less */ /* * On last reference drop, mark the route as belong to us so that it can be * timed out. */ static void in_clsroute(struct radix_node *rn, struct radix_node_head *head) { struct rtentry *rt = (struct rtentry *)rn; if(!(rt->rt_flags & RTF_UP)) return; /* prophylactic measures */ if((rt->rt_flags & (RTF_LLINFO | RTF_HOST)) != RTF_HOST) return; if((rt->rt_flags & (RTF_WASCLONED | RTPRF_OURS)) != RTF_WASCLONED) return; /* * As requested by David Greenman: * If rtq_reallyold is 0, just delete the route without * waiting for a timeout cycle to kill it. */ if(rtq_reallyold != 0) { rt->rt_flags |= RTPRF_OURS; rt->rt_rmx.rmx_expire = time.tv_sec + rtq_reallyold; } else { rtrequest(RTM_DELETE, (struct sockaddr *)rt_key(rt), rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0); } } struct rtqk_arg { struct radix_node_head *rnh; int draining; int killed; int found; int updating; time_t nextstop; }; /* * Get rid of old routes. When draining, this deletes everything, even when * the timeout is not expired yet. When updating, this makes sure that * nothing has a timeout longer than the current value of rtq_reallyold. */ static int in_rtqkill(struct radix_node *rn, void *rock) { struct rtqk_arg *ap = rock; struct rtentry *rt = (struct rtentry *)rn; int err; if(rt->rt_flags & RTPRF_OURS) { ap->found++; if(ap->draining || rt->rt_rmx.rmx_expire <= time.tv_sec) { if(rt->rt_refcnt > 0) panic("rtqkill route really not free"); err = rtrequest(RTM_DELETE, (struct sockaddr *)rt_key(rt), rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0); if(err) { log(LOG_WARNING, "in_rtqkill: error %d\n", err); } else { ap->killed++; } } else { if(ap->updating && (rt->rt_rmx.rmx_expire - time.tv_sec > rtq_reallyold)) { rt->rt_rmx.rmx_expire = time.tv_sec + rtq_reallyold; } ap->nextstop = lmin(ap->nextstop, rt->rt_rmx.rmx_expire); } } return 0; } #define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */ int rtq_timeout = RTQ_TIMEOUT; static void in_rtqtimo(void *rock) { struct radix_node_head *rnh = rock; struct rtqk_arg arg; struct timeval atv; static time_t last_adjusted_timeout = 0; int s; arg.found = arg.killed = 0; arg.rnh = rnh; arg.nextstop = time.tv_sec + rtq_timeout; arg.draining = arg.updating = 0; s = splnet(); rnh->rnh_walktree(rnh, in_rtqkill, &arg); splx(s); /* * Attempt to be somewhat dynamic about this: * If there are ``too many'' routes sitting around taking up space, * then crank down the timeout, and see if we can't make some more * go away. However, we make sure that we will never adjust more * than once in rtq_timeout seconds, to keep from cranking down too * hard. */ if((arg.found - arg.killed > rtq_toomany) && (time.tv_sec - last_adjusted_timeout >= rtq_timeout) && rtq_reallyold > rtq_minreallyold) { rtq_reallyold = 2*rtq_reallyold / 3; if(rtq_reallyold < rtq_minreallyold) { rtq_reallyold = rtq_minreallyold; } last_adjusted_timeout = time.tv_sec; log(LOG_DEBUG, "in_rtqtimo: adjusted rtq_reallyold to %d\n", rtq_reallyold); arg.found = arg.killed = 0; arg.updating = 1; s = splnet(); rnh->rnh_walktree(rnh, in_rtqkill, &arg); splx(s); } atv.tv_usec = 0; atv.tv_sec = arg.nextstop; timeout(in_rtqtimo, rock, hzto(&atv)); } void in_rtqdrain(void) { struct radix_node_head *rnh = rt_tables[AF_INET]; struct rtqk_arg arg; int s; arg.found = arg.killed = 0; arg.rnh = rnh; arg.nextstop = 0; arg.draining = 1; arg.updating = 0; s = splnet(); rnh->rnh_walktree(rnh, in_rtqkill, &arg); splx(s); } /* * Initialize our routing tree. */ int in_inithead(void **head, int off) { struct radix_node_head *rnh; if(!rn_inithead(head, off)) return 0; if(head != (void **)&rt_tables[AF_INET]) /* BOGUS! */ return 1; /* only do this for the real routing table */ rnh = *head; rnh->rnh_addaddr = in_addroute; rnh->rnh_matchaddr = in_matroute; rnh->rnh_close = in_clsroute; in_rtqtimo(rnh); /* kick off timeout first time */ return 1; }