add a bunch of comments to describe what's going on.
This is some of the worst code I've had to wade through in ages and I don't want to have to start from scratch again next time. (I have a 2.2 version of these comments, can I commit them?)
This commit is contained in:
Julian Elischer
parent
b70890c349
commit
499676df4d
141
sys/net/route.c
141
sys/net/route.c
@ -31,7 +31,7 @@
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* SUCH DAMAGE.
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*
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* @(#)route.c 8.2 (Berkeley) 11/15/93
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* $Id$
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* $Id: route.c,v 1.40 1997/02/22 09:41:14 peter Exp $
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*/
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#include "opt_mrouting.h"
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@ -186,34 +186,74 @@ rtalloc1(dst, report, ignflags)
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return (newrt);
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}
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/*
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* Remove a reference count from an rtentry.
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* If the count gets low enough, take it out of the routing table
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*/
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void
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rtfree(rt)
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register struct rtentry *rt;
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{
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/*
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* find the tree for that address family
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*/
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register struct radix_node_head *rnh =
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rt_tables[rt_key(rt)->sa_family];
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register struct ifaddr *ifa;
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if (rt == 0 || rnh == 0)
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panic("rtfree");
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/*
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* decrement the reference count by one and if it reaches 0,
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* and there is a close function defined, call the close function
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*/
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rt->rt_refcnt--;
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if(rnh->rnh_close && rt->rt_refcnt == 0) {
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rnh->rnh_close((struct radix_node *)rt, rnh);
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}
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/*
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* If we are no longer "up" (and ref == 0)
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* then we can free the resources associated
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* with the route.
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*/
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if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_UP) == 0) {
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if (rt->rt_nodes->rn_flags & (RNF_ACTIVE | RNF_ROOT))
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panic ("rtfree 2");
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/*
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* the rtentry must have been removed from the routing table
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* so it is represented in rttrash.. remove that now.
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*/
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rttrash--;
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#ifdef DIAGNOSTIC
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if (rt->rt_refcnt < 0) {
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printf("rtfree: %p not freed (neg refs)\n", rt);
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return;
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}
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ifa = rt->rt_ifa;
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IFAFREE(ifa);
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#endif
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/*
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* release references on items we hold them on..
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* e.g other routes and ifaddrs.
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*/
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if((ifa = rt->rt_ifa))
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IFAFREE(ifa);
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if (rt->rt_parent) {
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RTFREE(rt->rt_parent);
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}
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/*
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* The key is separatly alloc'd so free it (see rt_setgate()).
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* This also frees the gateway, as they are always malloc'd
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* together.
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*/
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Free(rt_key(rt));
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/*
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* and the rtentry itself of course
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*/
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Free(rt);
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}
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}
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@ -303,6 +343,9 @@ rtredirect(dst, gateway, netmask, flags, src, rtp)
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rt->rt_flags |= RTF_MODIFIED;
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flags |= RTF_MODIFIED;
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stat = &rtstat.rts_newgateway;
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/*
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* add the key and gateway (in one malloc'd chunk).
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*/
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rt_setgate(rt, rt_key(rt), gateway);
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}
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} else
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@ -470,19 +513,27 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
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* NB: RTF_UP must be set during the search above,
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* because we might delete the last ref, causing
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* rt to get freed prematurely.
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* eh? then why not just add a reference?
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* I'm not sure how RTF_UP helps matters. (JRE)
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*/
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rt->rt_flags &= ~RTF_UP;
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/*
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* If there is llinfo or similar associated with the
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* route, give the protocol a chance to deal with it..
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* give the protocol a chance to keep things in sync.
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*/
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if ((ifa = rt->rt_ifa) && ifa->ifa_rtrequest)
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ifa->ifa_rtrequest(RTM_DELETE, rt, SA(0));
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rttrash++;
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/*
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* If the caller wants it, then it can have it, but it's up to it
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* to free the rtentry as we won't be doing it.
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* one more rtentry floating around that is not
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* linked to the routing table.
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*/
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rttrash++;
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/*
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* If the caller wants it, then it can have it,
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* but it's up to it to free the rtentry as we won't be
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* doing it.
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*/
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if (ret_nrt)
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*ret_nrt = rt;
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@ -517,19 +568,32 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
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senderr(ENOBUFS);
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Bzero(rt, sizeof(*rt));
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rt->rt_flags = RTF_UP | flags;
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/*
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* Add the gateway. Possibly re-malloc-ing the storage for it
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* also add the rt_gwroute if possible.
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*/
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if (error = rt_setgate(rt, dst, gateway)) {
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Free(rt);
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senderr(error);
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}
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/*
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* point to the (possibly newly malloc'd) dest address.
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*/
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ndst = rt_key(rt);
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/*
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* make sure it contains the value we want (masked if needed).
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*/
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if (netmask) {
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rt_maskedcopy(dst, ndst, netmask);
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} else
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Bcopy(dst, ndst, dst->sa_len);
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/*
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* Note that we now have a reference to the ifa.
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* This moved from below so that rnh->rnh_addaddr() can
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* examine the ifa and ifp if it so desires.
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* examine the ifa and ifa->ifa_ifp if it so desires.
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*/
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ifa->ifa_refcnt++;
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rt->rt_ifa = ifa;
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@ -557,10 +621,15 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
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(caddr_t)netmask,
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rnh, rt->rt_nodes);
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} else if (rt2) {
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/* undo the extra ref we got */
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RTFREE(rt2);
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}
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}
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/*
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* If it still failed to go into the tree,
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* then un-make it (this should be a function)
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*/
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if (rn == 0) {
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if (rt->rt_gwroute)
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rtfree(rt->rt_gwroute);
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@ -571,8 +640,14 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
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Free(rt);
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senderr(EEXIST);
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}
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rt->rt_parent = 0;
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/*
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* If we got here from RESOLVE, then we are cloning
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* so clone the rest, and note that we
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* are a clone (and increment the parent's references)
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*/
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if (req == RTM_RESOLVE) {
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rt->rt_rmx = (*ret_nrt)->rt_rmx; /* copy metrics */
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if ((*ret_nrt)->rt_flags & RTF_PRCLONING) {
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@ -580,8 +655,14 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
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(*ret_nrt)->rt_refcnt++;
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}
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}
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/*
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* if this protocol has something to add to this then
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* allow it to do that as well.
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*/
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if (ifa->ifa_rtrequest)
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ifa->ifa_rtrequest(req, rt, SA(ret_nrt ? *ret_nrt : 0));
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/*
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* We repeat the same procedure from rt_setgate() here because
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* it doesn't fire when we call it there because the node
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@ -595,6 +676,10 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
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rt_fixchange, &arg);
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}
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/*
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* actually return a resultant rtentry and
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* give the caller a single reference.
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*/
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if (ret_nrt) {
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*ret_nrt = rt;
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rt->rt_refcnt++;
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@ -737,6 +822,12 @@ rt_setgate(rt0, dst, gate)
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return EADDRNOTAVAIL;
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}
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/*
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* Both dst and gateway are stored in the same malloc'd chunk
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* (If I ever get my hands on....)
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* if we need to malloc a new chunk, then keep the old one around
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* till we don't need it any more.
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*/
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if (rt->rt_gateway == 0 || glen > ROUNDUP(rt->rt_gateway->sa_len)) {
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old = (caddr_t)rt_key(rt);
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R_Malloc(new, caddr_t, dlen + glen);
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@ -744,14 +835,31 @@ rt_setgate(rt0, dst, gate)
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return ENOBUFS;
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rt->rt_nodes->rn_key = new;
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} else {
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/*
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* otherwise just overwrite the old one
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*/
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new = rt->rt_nodes->rn_key;
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old = 0;
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}
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/*
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* copy the new gateway value into the memory chunk
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*/
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Bcopy(gate, (rt->rt_gateway = (struct sockaddr *)(new + dlen)), glen);
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/*
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* if we are replacing the chunk (or it's new) we need to
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* replace the dst as well
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*/
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if (old) {
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Bcopy(dst, new, dlen);
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Free(old);
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}
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/*
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* If there is already a gwroute, it's now almost definitly wrong
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* so drop it.
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*/
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if (rt->rt_gwroute) {
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rt = rt->rt_gwroute; RTFREE(rt);
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rt = rt0; rt->rt_gwroute = 0;
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@ -764,7 +872,7 @@ rt_setgate(rt0, dst, gate)
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* protocol-cloning to operate for gateways (which is probably the
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* correct choice anyway), and avoid the resulting reference loops
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* by disallowing any route to run through itself as a gateway.
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* This is obviuosly mandatory when we get rt->rt_output().
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* This is obviously mandatory when we get rt->rt_output().
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*/
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if (rt->rt_flags & RTF_GATEWAY) {
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rt->rt_gwroute = rtalloc1(gate, 1, RTF_PRCLONING);
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@ -847,7 +955,7 @@ rtinit(ifa, cmd, flags)
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}
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/*
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* Get an rtentry that is in the routing tree and
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* contains the correct info. (if this fails we can't get there).
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* contains the correct info. (if this fails, can't get there).
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* We set "report" to FALSE so that if it doesn't exist,
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* it doesn't report an error or clone a route, etc. etc.
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*/
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@ -925,9 +1033,9 @@ rtinit(ifa, cmd, flags)
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printf("rtinit: wrong ifa (%p) was (%p)\n", ifa,
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rt->rt_ifa);
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/*
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* Ask that the route we got back be removed
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* from the routing tables as we are trying
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* to supersede it.
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* Ask that the protocol in question
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* remove anything it has associated with
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* this route and ifaddr.
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*/
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if (rt->rt_ifa->ifa_rtrequest)
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rt->rt_ifa->ifa_rtrequest(RTM_DELETE, rt, SA(0));
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@ -943,9 +1051,8 @@ rtinit(ifa, cmd, flags)
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rt->rt_ifp = ifa->ifa_ifp;
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ifa->ifa_refcnt++;
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/*
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* Now add it to the routing table
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* XXX could we have just left it?
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* as it might have been in the right place..
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* Now ask the protocol to check if it needs
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* any special processing in it's new form.
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*/
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if (ifa->ifa_rtrequest)
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ifa->ifa_rtrequest(RTM_ADD, rt, SA(0));
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