route.c

RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating sys

			ifa->ifa_rtrequest(RTM_DELETE, rt, SA(0));
		rttrash++;
		/*
		 * If the caller wants it, then it can have it, but it's up to it
		 * to free the rtentry as we won't be doing it.
		 */
		if (ret_nrt)
			*ret_nrt = rt;
		else if (rt->rt_refcnt <= 0) {
			rt->rt_refcnt++; /* make a 1->0 transition */
			rtfree(rt);
		}
		break;

	case RTM_RESOLVE:
		if (ret_nrt == 0 || (rt = *ret_nrt) == 0)
			senderr(EINVAL);
		ifa = rt->rt_ifa;
		flags = rt->rt_flags &
		    ~(RTF_CLONING | RTF_PRCLONING | RTF_STATIC);
		flags |= RTF_WASCLONED;
		gateway = rt->rt_gateway;
		if ((netmask = rt->rt_genmask) == 0)
			flags |= RTF_HOST;
		goto makeroute;

	case RTM_ADD:
		if ((flags & RTF_GATEWAY) && !gateway)
			panic("rtrequest: GATEWAY but no gateway");

		if ((ifa = ifa_ifwithroute(flags, dst, gateway)) == 0)
			senderr(ENETUNREACH);

	makeroute:
		R_Malloc(rt, struct rtentry *, sizeof(*rt));
		if (rt == 0)
			senderr(ENOBUFS);
		Bzero(rt, sizeof(*rt));
		rt->rt_flags = RTF_UP | flags;
		if ((error = rt_setgate(rt, dst, gateway))) {
			Free(rt);
			senderr(error);
		}
		ndst = rt_key(rt);
		if (netmask) {
			rt_maskedcopy(dst, ndst, netmask);
		} else
			Bcopy(dst, ndst, dst->sa_len);

		/*
		 * This moved from below so that rnh->rnh_addaddr() can
		 * examine the ifa and ifp if it so desires.
		 */
		ifa->ifa_refcnt++;
		rt->rt_ifa = ifa;
		rt->rt_ifp = ifa->ifa_ifp;

		rn = rnh->rnh_addaddr((caddr_t)ndst, (caddr_t)netmask,
					rnh, rt->rt_nodes);
		if (rn == 0) {
			struct rtentry *rt2;
			/*
			 * Uh-oh, we already have one of these in the tree.
			 * We do a special hack: if the route that's already
			 * there was generated by the protocol-cloning
			 * mechanism, then we just blow it away and retry
			 * the insertion of the new one.
			 */
			rt2 = rtalloc1(dst, 0, RTF_PRCLONING);
			if (rt2 && rt2->rt_parent) {
				rtrequest(RTM_DELETE, 
					  (struct sockaddr *)rt_key(rt2),
					  rt2->rt_gateway,
					  rt_mask(rt2), rt2->rt_flags, 0);
				RTFREE(rt2);
				rn = rnh->rnh_addaddr((caddr_t)ndst,
						      (caddr_t)netmask,
						      rnh, rt->rt_nodes);
			} else if (rt2) {
				RTFREE(rt2);
			}
		}

		if (rn == 0) {
			if (rt->rt_gwroute)
				rtfree(rt->rt_gwroute);
			if (rt->rt_ifa) {
				IFAFREE(rt->rt_ifa);
			}
			Free(rt_key(rt));
			Free(rt);
			senderr(EEXIST);
		}
		rt->rt_parent = 0;

		if (req == RTM_RESOLVE) {
			rt->rt_rmx = (*ret_nrt)->rt_rmx; /* copy metrics */
			if ((*ret_nrt)->rt_flags & RTF_PRCLONING) {
				rt->rt_parent = (*ret_nrt);
				(*ret_nrt)->rt_refcnt++;
			}
		}
		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) && 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);
		}

		if (ret_nrt) {
			*ret_nrt = rt;
			rt->rt_refcnt++;
		}
		break;
	}
bad:
	splx(s);
	return (error);
}

/*
 * Called from rtrequest(RTM_DELETE, ...) to fix up the route's ``family''
 * (i.e., the routes related to it by the operation of cloning).  This
 * routine is iterated over all potential former-child-routes by way of
 * rnh->rnh_walktree_from() above, and those that actually are children of
 * the late parent (passed in as VP here) are themselves deleted.
 */
static int
rt_fixdelete(struct radix_node *rn, void *vp)
{
	struct rtentry *rt = (struct rtentry *)rn;
	struct rtentry *rt0 = vp;

	if (rt->rt_parent == rt0 && !(rt->rt_flags & RTF_PINNED)) {
		return rtrequest(RTM_DELETE, rt_key(rt),
				 (struct sockaddr *)0, rt_mask(rt),
				 rt->rt_flags, (struct rtentry **)0);
	}
	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;
	struct sockaddr *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];

	/*
	 * A host route with the destination equal to the gateway
	 * will interfere with keeping LLINFO in the routing
	 * table, so disallow it.
	 */
	if (((rt0->rt_flags & (RTF_HOST|RTF_GATEWAY|RTF_LLINFO)) ==
					(RTF_HOST|RTF_GATEWAY)) &&
	    (dst->sa_len == gate->sa_len) &&
	    (bcmp(dst, gate, dst->sa_len) == 0)) {
		/*
		 * The route might already exist if this is an RTM_CHANGE
		 * or a routing redirect, so try to delete it.
		 */
		if (rt_key(rt0))
			rtrequest(RTM_DELETE, (struct sockaddr *)rt_key(rt0),
			    rt0->rt_gateway, rt_mask(rt0), rt0->rt_flags, 0);
		return EADDRNOTAVAIL;
	}

	if (rt->rt_gateway == 0 || glen > ROUNDUP(rt->rt_gateway->sa_len)) {
		old = (caddr_t)rt_key(rt);
		R_Malloc(new, caddr_t, dlen + glen);
		if (new == 0)
			return ENOBUFS;
		rt->rt_nodes->rn_key = new;
	} else {
		new = rt->rt_nodes->rn_key;
		old = 0;
	}
	Bcopy(gate, (rt->rt_gateway = (struct sockaddr *)(new + dlen)), glen);
	if (old) {
		Bcopy(dst, new, dlen);
		Free(old);
	}
	if (rt->rt_gwroute) {
		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, RTF_PRCLONING);
		if (rt->rt_gwroute == rt) {
			RTFREE(rt->rt_gwroute);
			rt->rt_gwroute = 0;
			return EDQUOT; /* 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;
}

static void
rt_maskedcopy(src, dst, netmask)
	struct sockaddr *src, *dst, *netmask;
{
	register u_char *cp1 = (u_char *)src;
	register u_char *cp2 = (u_char *)dst;
	register u_char *cp3 = (u_char *)netmask;
	u_char *cplim = cp2 + *cp3;
	u_char *cplim2 = cp2 + *cp1;

	*cp2++ = *cp1++; *cp2++ = *cp1++; /* copies sa_len & sa_family */
	cp3 += 2;
	if (cplim > cplim2)
		cplim = cplim2;
	while (cp2 < cplim)
		*cp2++ = *cp1++ & *cp3++;
	if (cp2 < cplim2)
		bzero((caddr_t)cp2, (unsigned)(cplim2 - cp2));
}

/*
 * Set up a routing table entry, normally
 * for an interface.
 */
int
rtinit(ifa, cmd, flags)
	register struct ifaddr *ifa;
	int cmd, flags;
{
	register struct rtentry *rt;
	register struct sockaddr *dst;
	register struct sockaddr *deldst;
	struct mbuf *m = 0;
	struct rtentry *nrt = 0;
	int error;

	dst = flags & RTF_HOST ? ifa->ifa_dstaddr : ifa->ifa_addr;
	/*
	 * If it's a delete, check that if it exists, it's on the correct
	 * interface or we might scrub a route to another ifa which would
	 * be confusing at best and possibly worse.
	 */
	if (cmd == RTM_DELETE) {
		/* 
		 * It's a delete, so it should already exist..
		 * If it's a net, mask off the host bits
		 * (Assuming we have a mask)
		 */
		if ((flags & RTF_HOST) == 0 && ifa->ifa_netmask) {
			m = m_get(M_WAIT, MT_SONAME);
			deldst = mtod(m, struct sockaddr *);
			rt_maskedcopy(dst, deldst, ifa->ifa_netmask);
			dst = deldst;
		}
		/*
		 * Get an rtentry that is in the routing tree and
		 * contains the correct info. (if this fails we can't get there).
		 * We set "report" to FALSE so that if it doesn't exist,
		 * it doesn't report an error or clone a route, etc. etc.
		 */
		rt = rtalloc1(dst, 0, 0UL);
		if (rt) {
			/*
			 * Ok so we found the rtentry. it has an extra reference
			 * for us at this stage. we won't need that so
			 * lop that off now.
			 */
			rt->rt_refcnt--;
			if (rt->rt_ifa != ifa) {
				/*
				 * If the interface in the rtentry doesn't match
				 * the interface we are using, then we don't
				 * want to delete it, so return an error.
				 * This seems to be the only point of 
				 * this whole RTM_DELETE clause.
				 */
				if (m)
					(void) m_free(m);
				return (flags & RTF_HOST ? EHOSTUNREACH
							: ENETUNREACH);
			}
		}
		/* XXX */
#if 0
		else {
			/* 
			 * One would think that as we are deleting, and we know
			 * it doesn't exist, we could just return at this point
			 * with an "ELSE" clause, but apparently not..
			 */
			return (flags & RTF_HOST ? EHOSTUNREACH
							: ENETUNREACH);
		}
#endif
	}
	/*
	 * Do the actual request
	 */
	error = rtrequest(cmd, dst, ifa->ifa_addr, ifa->ifa_netmask,
			flags | ifa->ifa_flags, &nrt);
	if (m)
		(void) m_free(m);
	/*
	 * If we are deleting, and we found an entry, then
	 * it's been removed from the tree.. now throw it away.
	 */
	if (cmd == RTM_DELETE && error == 0 && (rt = nrt)) {
		/*
		 * notify any listenning routing agents of the change
		 */
		rt_newaddrmsg(cmd, ifa, error, nrt);
		if (rt->rt_refcnt <= 0) {
			rt->rt_refcnt++; /* need a 1->0 transition to free */
			rtfree(rt);
		}
	}

	/*
	 * We are adding, and we have a returned routing entry.
	 * We need to sanity check the result.
	 */
	if (cmd == RTM_ADD && error == 0 && (rt = nrt)) {
		/*
		 * We just wanted to add it.. we don't actually need a reference
		 */
		rt->rt_refcnt--;
		/*
		 * If it came back with an unexpected interface, then it must 
		 * have already existed or something. (XXX)
		 */
		if (rt->rt_ifa != ifa) {
			printf("rtinit: wrong ifa (%p) was (%p)\n", ifa,
				rt->rt_ifa);
			/*
			 * Ask that the route we got back be removed
			 * from the routing tables as we are trying
			 * to supersede it.
			 */
			if (rt->rt_ifa->ifa_rtrequest)
			    rt->rt_ifa->ifa_rtrequest(RTM_DELETE, rt, SA(0));
			/* 
			 * Remove the referenve to the it's ifaddr.
			 */
			IFAFREE(rt->rt_ifa);
			/*
			 * And substitute in references to the ifaddr
			 * we are adding.
			 */
			rt->rt_ifa = ifa;
			rt->rt_ifp = ifa->ifa_ifp;
			ifa->ifa_refcnt++;
			/*
			 * Now add it to the routing table
			 * XXX could we have just left it?
			 * as it might have been in the right place..
			 */
			if (ifa->ifa_rtrequest)
			    ifa->ifa_rtrequest(RTM_ADD, rt, SA(0));
		}
		/*
		 * notify any listenning routing agents of the change
		 */
		rt_newaddrmsg(cmd, ifa, error, nrt);
	}
	return (error);
}