dn_fib.c

linux 内核源代码

	}

	fi->fib_treeref++;
	atomic_inc(&fi->fib_clntref);
	spin_lock(&dn_fib_info_lock);
	fi->fib_next = dn_fib_info_list;
	fi->fib_prev = NULL;
	if (dn_fib_info_list)
		dn_fib_info_list->fib_prev = fi;
	dn_fib_info_list = fi;
	spin_unlock(&dn_fib_info_lock);
	return fi;

err_inval:
	err = -EINVAL;

failure:
	*errp = err;
	if (fi) {
		fi->fib_dead = 1;
		dn_fib_free_info(fi);
	}

	return NULL;
}

int dn_fib_semantic_match(int type, struct dn_fib_info *fi, const struct flowi *fl, struct dn_fib_res *res)
{
	int err = dn_fib_props[type].error;

	if (err == 0) {
		if (fi->fib_flags & RTNH_F_DEAD)
			return 1;

		res->fi = fi;

		switch(type) {
			case RTN_NAT:
				DN_FIB_RES_RESET(*res);
				atomic_inc(&fi->fib_clntref);
				return 0;
			case RTN_UNICAST:
			case RTN_LOCAL:
				for_nexthops(fi) {
					if (nh->nh_flags & RTNH_F_DEAD)
						continue;
					if (!fl->oif || fl->oif == nh->nh_oif)
						break;
				}
				if (nhsel < fi->fib_nhs) {
					res->nh_sel = nhsel;
					atomic_inc(&fi->fib_clntref);
					return 0;
				}
				endfor_nexthops(fi);
				res->fi = NULL;
				return 1;
			default:
				if (net_ratelimit())
					 printk("DECnet: impossible routing event : dn_fib_semantic_match type=%d\n", type);
				res->fi = NULL;
				return -EINVAL;
		}
	}
	return err;
}

void dn_fib_select_multipath(const struct flowi *fl, struct dn_fib_res *res)
{
	struct dn_fib_info *fi = res->fi;
	int w;

	spin_lock_bh(&dn_fib_multipath_lock);
	if (fi->fib_power <= 0) {
		int power = 0;
		change_nexthops(fi) {
			if (!(nh->nh_flags&RTNH_F_DEAD)) {
				power += nh->nh_weight;
				nh->nh_power = nh->nh_weight;
			}
		} endfor_nexthops(fi);
		fi->fib_power = power;
		if (power < 0) {
			spin_unlock_bh(&dn_fib_multipath_lock);
			res->nh_sel = 0;
			return;
		}
	}

	w = jiffies % fi->fib_power;

	change_nexthops(fi) {
		if (!(nh->nh_flags&RTNH_F_DEAD) && nh->nh_power) {
			if ((w -= nh->nh_power) <= 0) {
				nh->nh_power--;
				fi->fib_power--;
				res->nh_sel = nhsel;
				spin_unlock_bh(&dn_fib_multipath_lock);
				return;
			}
		}
	} endfor_nexthops(fi);
	res->nh_sel = 0;
	spin_unlock_bh(&dn_fib_multipath_lock);
}


static int dn_fib_check_attr(struct rtmsg *r, struct rtattr **rta)
{
	int i;

	for(i = 1; i <= RTA_MAX; i++) {
		struct rtattr *attr = rta[i-1];
		if (attr) {
			if (RTA_PAYLOAD(attr) < 4 && RTA_PAYLOAD(attr) != 2)
				return -EINVAL;
			if (i != RTA_MULTIPATH && i != RTA_METRICS &&
			    i != RTA_TABLE)
				rta[i-1] = (struct rtattr *)RTA_DATA(attr);
		}
	}

	return 0;
}

static int dn_fib_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
{
	struct dn_fib_table *tb;
	struct rtattr **rta = arg;
	struct rtmsg *r = NLMSG_DATA(nlh);

	if (dn_fib_check_attr(r, rta))
		return -EINVAL;

	tb = dn_fib_get_table(rtm_get_table(rta, r->rtm_table), 0);
	if (tb)
		return tb->delete(tb, r, (struct dn_kern_rta *)rta, nlh, &NETLINK_CB(skb));

	return -ESRCH;
}

static int dn_fib_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
{
	struct dn_fib_table *tb;
	struct rtattr **rta = arg;
	struct rtmsg *r = NLMSG_DATA(nlh);

	if (dn_fib_check_attr(r, rta))
		return -EINVAL;

	tb = dn_fib_get_table(rtm_get_table(rta, r->rtm_table), 1);
	if (tb)
		return tb->insert(tb, r, (struct dn_kern_rta *)rta, nlh, &NETLINK_CB(skb));

	return -ENOBUFS;
}

static void fib_magic(int cmd, int type, __le16 dst, int dst_len, struct dn_ifaddr *ifa)
{
	struct dn_fib_table *tb;
	struct {
		struct nlmsghdr nlh;
		struct rtmsg rtm;
	} req;
	struct dn_kern_rta rta;

	memset(&req.rtm, 0, sizeof(req.rtm));
	memset(&rta, 0, sizeof(rta));

	if (type == RTN_UNICAST)
		tb = dn_fib_get_table(RT_MIN_TABLE, 1);
	else
		tb = dn_fib_get_table(RT_TABLE_LOCAL, 1);

	if (tb == NULL)
		return;

	req.nlh.nlmsg_len = sizeof(req);
	req.nlh.nlmsg_type = cmd;
	req.nlh.nlmsg_flags = NLM_F_REQUEST|NLM_F_CREATE|NLM_F_APPEND;
	req.nlh.nlmsg_pid = 0;
	req.nlh.nlmsg_seq = 0;

	req.rtm.rtm_dst_len = dst_len;
	req.rtm.rtm_table = tb->n;
	req.rtm.rtm_protocol = RTPROT_KERNEL;
	req.rtm.rtm_scope = (type != RTN_LOCAL ? RT_SCOPE_LINK : RT_SCOPE_HOST);
	req.rtm.rtm_type = type;

	rta.rta_dst = &dst;
	rta.rta_prefsrc = &ifa->ifa_local;
	rta.rta_oif = &ifa->ifa_dev->dev->ifindex;

	if (cmd == RTM_NEWROUTE)
		tb->insert(tb, &req.rtm, &rta, &req.nlh, NULL);
	else
		tb->delete(tb, &req.rtm, &rta, &req.nlh, NULL);
}

static void dn_fib_add_ifaddr(struct dn_ifaddr *ifa)
{

	fib_magic(RTM_NEWROUTE, RTN_LOCAL, ifa->ifa_local, 16, ifa);

#if 0
	if (!(dev->flags&IFF_UP))
		return;
	/* In the future, we will want to add default routes here */

#endif
}

static void dn_fib_del_ifaddr(struct dn_ifaddr *ifa)
{
	int found_it = 0;
	struct net_device *dev;
	struct dn_dev *dn_db;
	struct dn_ifaddr *ifa2;

	ASSERT_RTNL();

	/* Scan device list */
	read_lock(&dev_base_lock);
	for_each_netdev(&init_net, dev) {
		dn_db = dev->dn_ptr;
		if (dn_db == NULL)
			continue;
		for(ifa2 = dn_db->ifa_list; ifa2; ifa2 = ifa2->ifa_next) {
			if (ifa2->ifa_local == ifa->ifa_local) {
				found_it = 1;
				break;
			}
		}
	}
	read_unlock(&dev_base_lock);

	if (found_it == 0) {
		fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 16, ifa);

		if (dnet_addr_type(ifa->ifa_local) != RTN_LOCAL) {
			if (dn_fib_sync_down(ifa->ifa_local, NULL, 0))
				dn_fib_flush();
		}
	}
}

static void dn_fib_disable_addr(struct net_device *dev, int force)
{
	if (dn_fib_sync_down(0, dev, force))
		dn_fib_flush();
	dn_rt_cache_flush(0);
	neigh_ifdown(&dn_neigh_table, dev);
}

static int dn_fib_dnaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
{
	struct dn_ifaddr *ifa = (struct dn_ifaddr *)ptr;

	switch(event) {
		case NETDEV_UP:
			dn_fib_add_ifaddr(ifa);
			dn_fib_sync_up(ifa->ifa_dev->dev);
			dn_rt_cache_flush(-1);
			break;
		case NETDEV_DOWN:
			dn_fib_del_ifaddr(ifa);
			if (ifa->ifa_dev && ifa->ifa_dev->ifa_list == NULL) {
				dn_fib_disable_addr(ifa->ifa_dev->dev, 1);
			} else {
				dn_rt_cache_flush(-1);
			}
			break;
	}
	return NOTIFY_DONE;
}

static int dn_fib_sync_down(__le16 local, struct net_device *dev, int force)
{
	int ret = 0;
	int scope = RT_SCOPE_NOWHERE;

	if (force)
		scope = -1;

	for_fib_info() {
		/*
		 * This makes no sense for DECnet.... we will almost
		 * certainly have more than one local address the same
		 * over all our interfaces. It needs thinking about
		 * some more.
		 */
		if (local && fi->fib_prefsrc == local) {
			fi->fib_flags |= RTNH_F_DEAD;
			ret++;
		} else if (dev && fi->fib_nhs) {
			int dead = 0;

			change_nexthops(fi) {
				if (nh->nh_flags&RTNH_F_DEAD)
					dead++;
				else if (nh->nh_dev == dev &&
						nh->nh_scope != scope) {
					spin_lock_bh(&dn_fib_multipath_lock);
					nh->nh_flags |= RTNH_F_DEAD;
					fi->fib_power -= nh->nh_power;
					nh->nh_power = 0;
					spin_unlock_bh(&dn_fib_multipath_lock);
					dead++;
				}
			} endfor_nexthops(fi)
			if (dead == fi->fib_nhs) {
				fi->fib_flags |= RTNH_F_DEAD;
				ret++;
			}
		}
	} endfor_fib_info();
	return ret;
}


static int dn_fib_sync_up(struct net_device *dev)
{
	int ret = 0;

	if (!(dev->flags&IFF_UP))
		return 0;

	for_fib_info() {
		int alive = 0;

		change_nexthops(fi) {
			if (!(nh->nh_flags&RTNH_F_DEAD)) {
				alive++;
				continue;
			}
			if (nh->nh_dev == NULL || !(nh->nh_dev->flags&IFF_UP))
				continue;
			if (nh->nh_dev != dev || dev->dn_ptr == NULL)
				continue;
			alive++;
			spin_lock_bh(&dn_fib_multipath_lock);
			nh->nh_power = 0;
			nh->nh_flags &= ~RTNH_F_DEAD;
			spin_unlock_bh(&dn_fib_multipath_lock);
		} endfor_nexthops(fi);

		if (alive > 0) {
			fi->fib_flags &= ~RTNH_F_DEAD;
			ret++;
		}
	} endfor_fib_info();
	return ret;
}

static struct notifier_block dn_fib_dnaddr_notifier = {
	.notifier_call = dn_fib_dnaddr_event,
};

void __exit dn_fib_cleanup(void)
{
	dn_fib_table_cleanup();
	dn_fib_rules_cleanup();

	unregister_dnaddr_notifier(&dn_fib_dnaddr_notifier);
}


void __init dn_fib_init(void)
{
	dn_fib_table_init();
	dn_fib_rules_init();

	register_dnaddr_notifier(&dn_fib_dnaddr_notifier);

	rtnl_register(PF_DECnet, RTM_NEWROUTE, dn_fib_rtm_newroute, NULL);
	rtnl_register(PF_DECnet, RTM_DELROUTE, dn_fib_rtm_delroute, NULL);
}