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Finally finish the cloning cleanup work by making sure that clones

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go away whenever a clone's parent is changed, or a route is added in a
certain set of circumstances.

This also includes code to forbid setting a route's gateway to an
address which can only be reached through that route, thus (hopefully)
eliminating one class of cloning bottomless-recursion bugs.
This commit is contained in:
Garrett Wollman 1995-04-25 19:12:07 +00:00
parent 08af2cee88
commit cd02a0b741
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=8070
1 changed files with 131 additions and 1 deletions
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132
sys/net/route.c
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@ -350,6 +350,12 @@ ifa_ifwithroute(flags, dst, gateway)
#define ROUNDUP(a) (a>0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
static int rt_fixdelete(struct radix_node *, void *);
static int rt_fixchange(struct radix_node *, void *);
struct rtfc_arg {
struct rtentry *rt0;
struct radix_node_head *rnh;
};
int
rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
@ -466,6 +472,19 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
}
if (ifa->ifa_rtrequest)
ifa->ifa_rtrequest(req, rt, SA(ret_nrt ? *ret_nrt : 0));
/*
* We repeat the same procedure from rt_setgate() here because
* it doesn't fire when we call it there because the node
* hasn't been added to the tree yet.
*/
if (!(rt->rt_flags & RTF_HOST)) {
struct rtfc_arg arg;
arg.rnh = rnh;
arg.rt0 = rt;
rnh->rnh_walktree_from(rnh, rt_key(rt), rt_mask(rt),
rt_fixchange, &arg);
}
if (ret_nrt) {
*ret_nrt = rt;
rt->rt_refcnt++;
@ -498,6 +517,87 @@ rt_fixdelete(struct radix_node *rn, void *vp)
return 0;
}
/*
* This routine is called from rt_setgate() to do the analogous thing for
* adds and changes. There is the added complication in this case of a
* middle insert; i.e., insertion of a new network route between an older
* network route and (cloned) host routes. For this reason, a simple check
* of rt->rt_parent is insufficient; each candidate route must be tested
* against the (mask, value) of the new route (passed as before in vp)
* to see if the new route matches it. Unfortunately, this has the obnoxious
* property of also triggering for insertion /above/ a pre-existing network
* route and clones. Sigh. This may be fixed some day.
*
* XXX - it may be possible to do fixdelete() for changes and reserve this
* routine just for adds. I'm not sure why I thought it was necessary to do
* changes this way.
*/
#ifdef DEBUG
int rtfcdebug = 0;
#endif
static int
rt_fixchange(struct radix_node *rn, void *vp)
{
struct rtentry *rt = (struct rtentry *)rn;
struct rtfc_arg *ap = vp;
struct rtentry *rt0 = ap->rt0;
struct radix_node_head *rnh = ap->rnh;
u_char *xk1, *xm1, *xk2;
int i, len;
#ifdef DEBUG
if (rtfcdebug)
printf("rt_fixchange: rt %p, rt0 %p\n", rt, rt0);
#endif
if (!rt->rt_parent || (rt->rt_flags & RTF_PINNED)) {
#ifdef DEBUG
if(rtfcdebug) printf("no parent or pinned\n");
#endif
return 0;
}
if (rt->rt_parent == rt0) {
#ifdef DEBUG
if(rtfcdebug) printf("parent match\n");
#endif
return rtrequest(RTM_DELETE, rt_key(rt),
(struct sockaddr *)0, rt_mask(rt),
rt->rt_flags, (struct rtentry **)0);
}
/*
* There probably is a function somewhere which does this...
* if not, there should be.
*/
len = imin(((struct sockaddr *)rt_key(rt0))->sa_len,
((struct sockaddr *)rt_key(rt))->sa_len);
xk1 = (u_char *)rt_key(rt0);
xm1 = (u_char *)rt_mask(rt0);
xk2 = (u_char *)rt_key(rt);
for (i = rnh->rnh_treetop->rn_off; i < len; i++) {
if ((xk2[i] & xm1[i]) != xk1[i]) {
#ifdef DEBUG
if(rtfcdebug) printf("no match\n");
#endif
return 0;
}
}
/*
* OK, this node is a clone, and matches the node currently being
* changed/added under the node's mask. So, get rid of it.
*/
#ifdef DEBUG
if(rtfcdebug) printf("deleting\n");
#endif
return rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0,
rt_mask(rt), rt->rt_flags, (struct rtentry **)0);
}
int
rt_setgate(rt0, dst, gate)
struct rtentry *rt0;
@ -506,6 +606,7 @@ rt_setgate(rt0, dst, gate)
caddr_t new, old;
int dlen = ROUNDUP(dst->sa_len), glen = ROUNDUP(gate->sa_len);
register struct rtentry *rt = rt0;
struct radix_node_head *rnh = rt_tables[dst->sa_family];
if (rt->rt_gateway == 0 || glen > ROUNDUP(rt->rt_gateway->sa_len)) {
old = (caddr_t)rt_key(rt);
@ -526,9 +627,38 @@ rt_setgate(rt0, dst, gate)
rt = rt->rt_gwroute; RTFREE(rt);
rt = rt0; rt->rt_gwroute = 0;
}
/*
* Cloning loop avoidance:
* In the presence of protocol-cloning and bad configuration,
* it is possible to get stuck in bottomless mutual recursion
* (rtrequest rt_setgate rtalloc1). We avoid this by not allowing
* protocol-cloning to operate for gateways (which is probably the
* correct choice anyway), and avoid the resulting reference loops
* by disallowing any route to run through itself as a gateway.
* This is obviuosly mandatory when we get rt->rt_output().
*/
if (rt->rt_flags & RTF_GATEWAY) {
rt->rt_gwroute = rtalloc1(gate, 1, 0UL);
rt->rt_gwroute = rtalloc1(gate, 1, RTF_PRCLONING);
if (rt->rt_gwroute == rt) {
RTFREE(rt->rt_gwroute);
rt->rt_gwroute = 0;
return 1; /* failure */
}
}
/*
* This isn't going to do anything useful for host routes, so
* don't bother. Also make sure we have a reasonable mask
* (we don't yet have one during adds).
*/
if (!(rt->rt_flags & RTF_HOST) && rt_mask(rt) != 0) {
struct rtfc_arg arg;
arg.rnh = rnh;
arg.rt0 = rt;
rnh->rnh_walktree_from(rnh, rt_key(rt), rt_mask(rt),
rt_fixchange, &arg);
}
return 0;
}