route.c

来自「eCos操作系统源码」· C语言 代码 · 共 1,191 行 · 第 1/3 页

			stat = &rtstat.rts_dynamic;
		} else {
			/*
			 * Smash the current notion of the gateway to
			 * this destination.  Should check about netmask!!!
			 */
			rt->rt_flags |= RTF_MODIFIED;
			flags |= RTF_MODIFIED;
			stat = &rtstat.rts_newgateway;
			/*
			 * add the key and gateway (in one malloc'd chunk).
			 */
			rt_setgate(rt, rt_key(rt), gateway);
		}
	} else
		error = EHOSTUNREACH;
done:
	if (rt) {
		if (rtp && !error)
			*rtp = rt;
		else
			rtfree(rt);
	}
out:
	if (error)
		rtstat.rts_badredirect++;
	else if (stat != NULL)
		(*stat)++;
	bzero((caddr_t)&info, sizeof(info));
	info.rti_info[RTAX_DST] = dst;
	info.rti_info[RTAX_GATEWAY] = gateway;
	info.rti_info[RTAX_NETMASK] = netmask;
	info.rti_info[RTAX_AUTHOR] = src;
	rt_missmsg(RTM_REDIRECT, &info, flags, error);
}

/*
* Routing table ioctl interface.
*/
int
rtioctl(req, data, p)
	int req;
	caddr_t data;
	struct proc *p;
{
#ifdef INET
    struct ecos_rtentry *rt;
    int res;

    switch (req) {
    case SIOCADDRT:
        rt = (struct ecos_rtentry *)data;
        res = rtrequest(RTM_ADD, 
                        &rt->rt_dst,
                        &rt->rt_gateway,
                        &rt->rt_genmask,
                        rt->rt_flags,
                        NULL);
        return (res);
    case SIOCDELRT:
        rt = (struct ecos_rtentry *)data;
        res = rtrequest(RTM_DELETE, 
                        &rt->rt_dst,
                        &rt->rt_gateway,
                        &rt->rt_genmask,
                        rt->rt_flags,
                        NULL);
        return (res);
    default:
        break;
    }
	/* Multicast goop, grrr... */
#ifdef MROUTING
	return mrt_ioctl(req, data);
#else
	return mrt_ioctl(req, data, p);
#endif
#else /* INET */
	return ENXIO;
#endif /* INET */
}

struct ifaddr *
ifa_ifwithroute(flags, dst, gateway)
	int flags;
	struct sockaddr	*dst, *gateway;
{
	register struct ifaddr *ifa;
	if ((flags & RTF_GATEWAY) == 0) {
		/*
		 * If we are adding a route to an interface,
		 * and the interface is a pt to pt link
		 * we should search for the destination
		 * as our clue to the interface.  Otherwise
		 * we can use the local address.
		 */
		ifa = 0;
		if (flags & RTF_HOST) {
			ifa = ifa_ifwithdstaddr(dst);
		}
		if (ifa == 0)
			ifa = ifa_ifwithaddr(gateway);
	} else {
		/*
		 * If we are adding a route to a remote net
		 * or host, the gateway may still be on the
		 * other end of a pt to pt link.
		 */
		ifa = ifa_ifwithdstaddr(gateway);
	}
	if (ifa == 0)
		ifa = ifa_ifwithnet(gateway);
	if (ifa == 0) {
		struct rtentry *rt = rtalloc1(dst, 0, 0UL);
		if (rt == 0)
			return (0);
		rt->rt_refcnt--;
		if ((ifa = rt->rt_ifa) == 0)
			return (0);
	}
	if (ifa->ifa_addr->sa_family != dst->sa_family) {
		struct ifaddr *oifa = ifa;
		ifa = ifaof_ifpforaddr(dst, ifa->ifa_ifp);
		if (ifa == 0)
			ifa = oifa;
	}
	return (ifa);
}

#define ROUNDUP(a) (a>0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))

static int rt_fixdelete __P((struct radix_node *, void *));
static int rt_fixchange __P((struct radix_node *, void *));

struct rtfc_arg {
	struct rtentry *rt0;
	struct radix_node_head *rnh;
};

/*
 * Do appropriate manipulations of a routing tree given
 * all the bits of info needed
 */
int
rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
	int req, flags;
	struct sockaddr *dst, *gateway, *netmask;
	struct rtentry **ret_nrt;
{
	int s = splnet(); int error = 0;
	register struct rtentry *rt;
	register struct radix_node *rn;
	register struct radix_node_head *rnh;
	struct ifaddr *ifa;
	struct sockaddr *ndst;
#define senderr(x) { error = x ; goto bad; }

	/*
	 * Find the correct routing tree to use for this Address Family
	 */
	if ((rnh = rt_tables[dst->sa_family]) == 0)
		senderr(ESRCH);
	/*
	 * If we are adding a host route then we don't want to put
	 * a netmask in the tree
	 */
	if (flags & RTF_HOST)
		netmask = 0;
	switch (req) {
	case RTM_DELETE:
		/*
		 * Remove the item from the tree and return it.
		 * Complain if it is not there and do no more processing.
		 */
		if ((rn = rnh->rnh_deladdr(dst, netmask, rnh)) == 0)
			senderr(ESRCH);
		if (rn->rn_flags & (RNF_ACTIVE | RNF_ROOT))
			panic ("rtrequest delete");
		rt = (struct rtentry *)rn;

		/*
		 * Now search what's left of the subtree for any cloned
		 * routes which might have been formed from this node.
		 */
		if ((rt->rt_flags & (RTF_CLONING | RTF_PRCLONING)) &&
		    rt_mask(rt)) {
			rnh->rnh_walktree_from(rnh, dst, rt_mask(rt),
					       rt_fixdelete, rt);
		}

		/*
		 * Remove any external references we may have.
		 * This might result in another rtentry being freed if
		 * we held its last reference.
		 */
		if (rt->rt_gwroute) {
		    if (rt != rt->rt_gwroute)
			RTFREE( rt->rt_gwroute ); // Free it up as normal
		    else
			rt->rt_refcnt--; // Just dec the refcount - freeing
					 // it here would be premature
		    rt->rt_gwroute = NULL;
		}

		/*
		 * NB: RTF_UP must be set during the search above,
		 * because we might delete the last ref, causing
		 * rt to get freed prematurely.
		 *  eh? then why not just add a reference?
		 * I'm not sure how RTF_UP helps matters. (JRE)
		 */
		rt->rt_flags &= ~RTF_UP;

		/*
		 * give the protocol a chance to keep things in sync.
		 */
		if ((ifa = rt->rt_ifa) && ifa->ifa_rtrequest)
			ifa->ifa_rtrequest(RTM_DELETE, rt, SA(0));

		/*
		 * one more rtentry floating around that is not
		 * linked to the routing table.
		 */
		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;
		/*
		 * Add the gateway. Possibly re-malloc-ing the storage for it
		 * also add the rt_gwroute if possible.
		 */
		if ((error = rt_setgate(rt, dst, gateway)) != 0) {
			Free(rt);
			senderr(error);
		}

		/*
		 * point to the (possibly newly malloc'd) dest address.
		 */
		ndst = rt_key(rt);

		/*
		 * make sure it contains the value we want (masked if needed).
		 */
		if (netmask) {
			rt_maskedcopy(dst, ndst, netmask);
		} else
			Bcopy(dst, ndst, dst->sa_len);

		/*
		 * Note that we now have a reference to the ifa.
		 * This moved from below so that rnh->rnh_addaddr() can
		 * examine the ifa and  ifa->ifa_ifp if it so desires.
		 */
		ifa->ifa_refcnt++;
		rt->rt_ifa = ifa;
		rt->rt_ifp = ifa->ifa_ifp;
		/* XXX mtu manipulation will be done in rnh_addaddr -- itojun */

		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) {
				/* undo the extra ref we got */
				RTFREE(rt2);
			}
		}

		/*
		 * If it still failed to go into the tree,
		 * then un-make it (this should be a function)
		 */
		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 we got here from RESOLVE, then we are cloning
		 * so clone the rest, and note that we
		 * are a clone (and increment the parent's references)
		 */
		if (req == RTM_RESOLVE) {
			rt->rt_rmx = (*ret_nrt)->rt_rmx; /* copy metrics */
			if ((*ret_nrt)->rt_flags & (RTF_CLONING | RTF_PRCLONING)) {
				rt->rt_parent = (*ret_nrt);
				(*ret_nrt)->rt_refcnt++;
			}
		}

		/*
		 * if this protocol has something to add to this then
		 * allow it to do that as well.
		 */
		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);
		}

		/*
		 * actually return a resultant rtentry and
		 * give the caller a single reference.
		 */
		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(rn, vp)
	struct radix_node *rn;