/*
* DECnet An implementation of the DECnet protocol suite for the LINUX
* operating system. DECnet is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* DECnet Routing Forwarding Information Base (Glue/Info List)
*
* Author: Steve Whitehouse <SteveW@ACM.org>
*
*
* Changes:
* Alexey Kuznetsov : SMP locking changes
* Steve Whitehouse : Rewrote it... Well to be more correct, I
* copied most of it from the ipv4 fib code.
* Steve Whitehouse : Updated it in style and fixed a few bugs
* which were fixed in the ipv4 code since
* this code was copied from it.
*
*/
#include <linux/string.h>
#include <linux/net.h>
#include <linux/socket.h>
#include <linux/slab.h>
#include <linux/sockios.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/proc_fs.h>
#include <linux/netdevice.h>
#include <linux/timer.h>
#include <linux/spinlock.h>
#include <linux/atomic.h>
#include <asm/uaccess.h>
#include <net/neighbour.h>
#include <net/dst.h>
#include <net/flow.h>
#include <net/fib_rules.h>
#include <net/dn.h>
#include <net/dn_route.h>
#include <net/dn_fib.h>
#include <net/dn_neigh.h>
#include <net/dn_dev.h>
#define RT_MIN_TABLE 1
#define for_fib_info() { struct dn_fib_info *fi;\
for(fi = dn_fib_info_list; fi; fi = fi->fib_next)
#define endfor_fib_info() }
#define for_nexthops(fi) { int nhsel; const struct dn_fib_nh *nh;\
for(nhsel = 0, nh = (fi)->fib_nh; nhsel < (fi)->fib_nhs; nh++, nhsel++)
#define change_nexthops(fi) { int nhsel; struct dn_fib_nh *nh;\
for(nhsel = 0, nh = (struct dn_fib_nh *)((fi)->fib_nh); nhsel < (fi)->fib_nhs; nh++, nhsel++)
#define endfor_nexthops(fi) }
static DEFINE_SPINLOCK(dn_fib_multipath_lock);
static struct dn_fib_info *dn_fib_info_list;
static DEFINE_SPINLOCK(dn_fib_info_lock);
static struct
{
int error;
u8 scope;
} dn_fib_props[RTN_MAX+1] = {
[RTN_UNSPEC] = { .error = 0, .scope = RT_SCOPE_NOWHERE },
[RTN_UNICAST] = { .error = 0, .scope = RT_SCOPE_UNIVERSE },
[RTN_LOCAL] = { .error = 0, .scope = RT_SCOPE_HOST },
[RTN_BROADCAST] = { .error = -EINVAL, .scope = RT_SCOPE_NOWHERE },
[RTN_ANYCAST] = { .error = -EINVAL, .scope = RT_SCOPE_NOWHERE },
[RTN_MULTICAST] = { .error = -EINVAL, .scope = RT_SCOPE_NOWHERE },
[RTN_BLACKHOLE] = { .error = -EINVAL, .scope = RT_SCOPE_UNIVERSE },
[RTN_UNREACHABLE] = { .error = -EHOSTUNREACH, .scope = RT_SCOPE_UNIVERSE },
[RTN_PROHIBIT] = { .error = -EACCES, .scope = RT_SCOPE_UNIVERSE },
[RTN_THROW] = { .error = -EAGAIN, .scope = RT_SCOPE_UNIVERSE },
[RTN_NAT] = { .error = 0, .scope = RT_SCOPE_NOWHERE },
[RTN_XRESOLVE] = { .error = -EINVAL, .scope = RT_SCOPE_NOWHERE },
};
static int dn_fib_sync_down(__le16 local, struct net_device *dev, int force);
static int dn_fib_sync_up(struct net_device *dev);
void dn_fib_free_info(struct dn_fib_info *fi)
{
if (fi->fib_dead == 0) {
printk(KERN_DEBUG "DECnet: BUG! Attempt to free alive dn_fib_info\n");
return;
}
change_nexthops(fi) {
if (nh->nh_dev)
dev_put(nh->nh_dev);
nh->nh_dev = NULL;
} endfor_nexthops(fi);
kfree(fi);
}
void dn_fib_release_info(struct dn_fib_info *fi)
{
spin_lock(&dn_fib_info_lock);
if (fi && --fi->fib_treeref == 0) {
if (fi->fib_next)
fi->fib_next->fib_prev = fi->fib_prev;
if (fi->fib_prev)
fi->fib_prev->fib_next = fi->fib_next;
if (fi == dn_fib_info_list)
dn_fib_info_list = fi->fib_next;
fi->fib_dead = 1;
dn_fib_info_put(fi);
}
spin_unlock(&dn_fib_info_lock);
}
static inline int dn_fib_nh_comp(const struct dn_fib_info *fi, const struct dn_fib_info *ofi)
{
const struct dn_fib_nh *onh = ofi->fib_nh;
for_nexthops(fi) {
if (nh->nh_oif != onh->nh_oif ||
nh->nh_gw != onh->nh_gw ||
nh->nh_scope != onh->nh_scope ||
nh->nh_weight != onh->nh_weight ||
((nh->nh_flags^onh->nh_flags)&~RTNH_F_DEAD))
return -1;
onh++;
} endfor_nexthops(fi);
return 0;
}
static inline struct dn_fib_info *dn_fib_find_info(const struct dn_fib_info *nfi)
{
for_fib_info() {
if (fi->fib_nhs != nfi->fib_nhs)
continue;
if (nfi->fib_protocol == fi->fib_protocol &&
nfi->fib_prefsrc == fi->fib_prefsrc &&
nfi->fib_priority == fi->fib_priority &&
memcmp(nfi->fib_metrics, fi->fib_metrics, sizeof(fi->fib_metrics)) == 0 &&
((nfi->fib_flags^fi->fib_flags)&~RTNH_F_DEAD) == 0 &&
(nfi->fib_nhs == 0 || dn_fib_nh_comp(fi, nfi) == 0))
return fi;
} endfor_fib_info();
return NULL;
}
__le16 dn_fib_get_attr16(struct rtattr *attr, int attrlen, int type)
{
while(RTA_OK(attr,attrlen)) {
if (attr->rta_type == type)
return *(__le16*)RTA_DATA(attr);
attr = RTA_NEXT(attr, attrlen);
}
return 0;
}
static int dn_fib_count_nhs(struct rtattr *rta)
{
int nhs = 0;
struct rtnexthop *nhp = RTA_DATA(rta);
int nhlen = RTA_PAYLOAD(rta);
while(nhlen >= (int)sizeof(struct rtnexthop)) {
if ((nhlen -= nhp->rtnh_len) < 0)
return 0;
nhs++;
nhp = RTNH_NEXT(nhp);
}
return nhs;
}
static int dn_fib_get_nhs(struct dn_fib_info *fi, const struct rtattr *rta, const struct rtmsg *r)
{
struct rtnexthop *nhp = RTA_DATA(rta);
int nhlen = RTA_PAYLOAD(rta);
change_nexthops(fi) {
int attrlen = nhlen - sizeof(struct rtnexthop);
if (attrlen < 0 || (nhlen -= nhp->rtnh_len) < 0)
return -EINVAL;
nh->nh_flags = (r->rtm_flags&~0xFF) | nhp->rtnh_flags;
nh->nh_oif = nhp->rtnh_ifindex;
nh->nh_weight = nhp->rtnh_hops + 1;
if (attrlen) {
nh->nh_gw = dn_fib_get_attr16(RTNH_DATA(nhp), attrlen, RTA_GATEWAY);
}
nhp = RTNH_NEXT(nhp);
} endfor_nexthops(fi);
return 0;
}
static int dn_fib_check_nh(const struct rtmsg *r, struct dn_fib_info *fi, struct dn_fib_nh *nh)
{
int err;
if (nh->nh_gw) {
struct flowidn fld;
struct dn_fib_res res;
if (nh->nh_flags&RTNH_F_ONLINK) {
struct net_device *dev;
if (r->rtm_scope >= RT_SCOPE_LINK)
return -EINVAL;
if (dnet_addr_type(nh->nh_gw) != RTN_UNICAST)
return -EINVAL;
if ((dev = __dev_get_by_index(&init_net, nh->nh_oif)) == NULL)
return -ENODEV;
if (!(dev->flags&IFF_UP))
return -ENETDOWN;
nh->nh_dev = dev;
dev_hold(dev);
nh->nh_scope = RT_SCOPE_LINK;
return 0;
}
memset(&fld, 0, sizeof(fld));
fld.daddr = nh->nh_gw;
fld.flowidn_oif = nh->nh_oif;
fld.flowidn_scope = r->rtm_scope + 1;
if (fld.flowidn_scope < RT_SCOPE_LINK)
fld.flowidn_scope = RT_SCOPE_LINK;
if ((err = dn_fib_lookup(&fld, &res)) != 0)
return err;
err = -EINVAL;
if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
goto out;
nh->nh_scope = res.scope;
nh->nh_oif = DN_FIB_RES_OIF(res);
nh->nh_dev = DN_FIB_RES_DEV(res);
if (nh->nh_dev == NULL)
goto out;
dev_hold(nh->nh_dev);
err = -ENETDOWN;
if (!(nh->nh_dev->flags & IFF_UP))
goto out;
err = 0;
out:
dn_fib_res_put(&res);
return err;
} else {
struct net_device *dev;
if (nh->nh_flags&(RTNH_F_PERVASIVE|RTNH_F_ONLINK))
return -EINVAL;
dev = __dev_get_by_index(&init_net, nh->nh_oif);
if (dev == NULL || dev->dn_ptr == NULL)
return -ENODEV;
if (!(dev->flags&IFF_UP))
return -ENETDOWN;
nh->nh_dev = dev;
dev_hold(nh->nh_dev);
nh->nh_scope = RT_SCOPE_HOST;
}
return 0;
}
struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, struct dn_kern_rta *rta, const struct nlmsghdr *nlh, int *errp)
{
int err;
struct dn_fib_info *fi = NULL;
struct dn_fib_info *ofi;
int nhs = 1;
if (r->rtm_type > RTN_MAX)
goto err_inval;
if (dn_fib_props[r->rtm_type].scope > r->rtm_scope)
goto err_inval;
if (rta->rta_mp) {
nhs = dn_fib_count_nhs(rta->rta_mp);
if (nhs == 0)
goto err_inval;
}
fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct dn_fib_nh), GFP_KERNEL);
err = -ENOBUFS;
if (fi == NULL)
goto failure;
fi->fib_protocol = r->rtm_protocol;
fi->fib_nhs = nhs;
fi->fib_flags = r->rtm_flags;
if (rta->rta_priority)
fi->fib_priority = *rta->rta_priority;
if (rta->rta_mx) {
int attrlen = RTA_PAYLOAD(rta->rta_mx);
struct rtattr *attr = RTA_DATA(rta->rta_mx);
while(RTA_OK(attr, attrlen)) {
unsigned int flavour = attr->rta_type;
if (flavour) {
if (flavour > RTAX_MAX)
goto err_inval;
fi->fib_metrics[flavour-1] = *(unsigned int *)RTA_DATA(attr);
}
attr = RTA_NEXT(attr, attrlen);
}
}
if (rta->rta_prefsrc)
memcpy(&fi->fib_prefsrc, rta->rta_prefsrc, 2);
if (rta->rta_mp) {
if ((err = dn_fib_get_nhs(fi, rta->rta_mp, r)) != 0)
goto failure;
if (rta->rta_oif && fi->fib_nh->nh_oif != *rta->rta_oif)
goto err_inval;
if (rta->rta_gw && memcmp(&fi->fib_nh->nh_gw, rta->rta_gw, 2))
goto err_inval;
} else {
struct dn_fib_nh *nh = fi->fib_nh;
if (rta->rta_oif)
nh->nh_oif = *rta->rta_oif;
if (rta->rta_gw)
memcpy(&nh->nh_gw, rta->rta_gw, 2);
nh->nh_flags = r->rtm_flags;
nh->nh_weight = 1;
}
if (r->rtm_type == RTN_NAT) {
if (rta->rta_gw == NULL || nhs != 1 || rta->rta_oif)
goto err_inval;
memcpy(&fi->fib_nh->nh_gw, rta->rta_gw, 2);
goto link_it;
}
if (dn_fib_props[r->rtm_type].error) {
if (rta->rta_gw || rta->rta_oif || rta->rta_mp)
goto err_inval;
goto link_it;
}
if (r->rtm_scope > RT_SCOPE_HOST)
goto err_inval;
if (r->rtm_scope == RT_SCOPE_HOST) {
struct dn_fib_nh *nh = fi->fib_nh;
/* Local address is added */
if (nhs != 1 || nh->nh_gw)
goto err_inval;
nh->nh_scope = RT_SCOPE_NOWHERE;
nh->nh_dev = dev_get_by_index(&init_net, fi->fib_nh->nh_oif);
err = -ENODEV;
if (nh->nh_dev == NULL)
goto failure;
} else {
change_nexthops(fi) {
if ((err = dn_fib_check_nh(r, fi, nh)) != 0)
goto failure;
} endfor_nexthops(fi)
}
if (fi->fib_prefsrc) {
if (r->rtm_type != RTN_LOCAL || rta->rta_dst == NULL ||
memcmp(&fi->fib_prefsrc, rta->rta_dst, 2))
if (dnet_addr_type(fi->fib_prefsrc) != RTN_LOCAL)
goto err_inval;
}
link_it:
if ((ofi = dn_fib_find_info(fi)) != NULL) {
fi->fib_dead = 1;
dn_fib_free_info(fi);
ofi->fib_treeref++;
return ofi;
}
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 flowidn *fld, 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 (!fld->flowidn_oif ||
fld->flowidn_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:
net_err_ratelimited("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 flowidn *fld, 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 net *net = sock_net(skb->sk);
struct dn_fib_table *tb;
struct rtattr **rta = arg;
struct rtmsg *r = NLMSG_DATA(nlh);
if (!net_eq(net, &init_net))
return -EINVAL;
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 net *net = sock_net(skb->sk);
struct dn_fib_table *tb;
struct rtattr **rta = arg;
struct rtmsg *r = NLMSG_DATA(nlh);
if (!net_eq(net, &init_net))
return -EINVAL;
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 */
rcu_read_lock();
for_each_netdev_rcu(&init_net, dev) {
dn_db = rcu_dereference(dev->dn_ptr);
if (dn_db == NULL)
continue;
for (ifa2 = rcu_dereference(dn_db->ifa_list);
ifa2 != NULL;
ifa2 = rcu_dereference(ifa2->ifa_next)) {
if (ifa2->ifa_local == ifa->ifa_local) {
found_it = 1;
break;
}
}
}
rcu_read_unlock();
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, NULL);
rtnl_register(PF_DECnet, RTM_DELROUTE, dn_fib_rtm_delroute, NULL, NULL);
}