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dn_route.c
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dn_route.c
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/*
* 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 Functions (Endnode and Router)
*
* Authors: Steve Whitehouse <[email protected]>
* Eduardo Marcelo Serrat <[email protected]>
*
* Changes:
* Steve Whitehouse : Fixes to allow "intra-ethernet" and
* "return-to-sender" bits on outgoing
* packets.
* Steve Whitehouse : Timeouts for cached routes.
* Steve Whitehouse : Use dst cache for input routes too.
* Steve Whitehouse : Fixed error values in dn_send_skb.
* Steve Whitehouse : Rework routing functions to better fit
* DECnet routing design
* Alexey Kuznetsov : New SMP locking
* Steve Whitehouse : More SMP locking changes & dn_cache_dump()
* Steve Whitehouse : Prerouting NF hook, now really is prerouting.
* Fixed possible skb leak in rtnetlink funcs.
* Steve Whitehouse : Dave Miller's dynamic hash table sizing and
* Alexey Kuznetsov's finer grained locking
* from ipv4/route.c.
* Steve Whitehouse : Routing is now starting to look like a
* sensible set of code now, mainly due to
* my copying the IPv4 routing code. The
* hooks here are modified and will continue
* to evolve for a while.
* Steve Whitehouse : Real SMP at last :-) Also new netfilter
* stuff. Look out raw sockets your days
* are numbered!
* Steve Whitehouse : Added return-to-sender functions. Added
* backlog congestion level return codes.
* Steve Whitehouse : Fixed bug where routes were set up with
* no ref count on net devices.
* Steve Whitehouse : RCU for the route cache
* Steve Whitehouse : Preparations for the flow cache
* Steve Whitehouse : Prepare for nonlinear skbs
*/
/******************************************************************************
(c) 1995-1998 E.M. Serrat [email protected]
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
*******************************************************************************/
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/inet.h>
#include <linux/route.h>
#include <linux/in_route.h>
#include <net/sock.h>
#include <linux/mm.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/init.h>
#include <linux/rtnetlink.h>
#include <linux/string.h>
#include <linux/netfilter_decnet.h>
#include <linux/rcupdate.h>
#include <linux/times.h>
#include <asm/errno.h>
#include <net/net_namespace.h>
#include <net/netlink.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_dev.h>
#include <net/dn_nsp.h>
#include <net/dn_route.h>
#include <net/dn_neigh.h>
#include <net/dn_fib.h>
struct dn_rt_hash_bucket
{
struct dn_route *chain;
spinlock_t lock;
} __attribute__((__aligned__(8)));
extern struct neigh_table dn_neigh_table;
static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};
static const int dn_rt_min_delay = 2 * HZ;
static const int dn_rt_max_delay = 10 * HZ;
static const int dn_rt_mtu_expires = 10 * 60 * HZ;
static unsigned long dn_rt_deadline;
static int dn_dst_gc(void);
static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
static void dn_dst_link_failure(struct sk_buff *);
static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu);
static int dn_route_input(struct sk_buff *);
static void dn_run_flush(unsigned long dummy);
static struct dn_rt_hash_bucket *dn_rt_hash_table;
static unsigned dn_rt_hash_mask;
static struct timer_list dn_route_timer;
static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush, 0, 0);
int decnet_dst_gc_interval = 2;
static struct dst_ops dn_dst_ops = {
.family = PF_DECnet,
.protocol = __constant_htons(ETH_P_DNA_RT),
.gc_thresh = 128,
.gc = dn_dst_gc,
.check = dn_dst_check,
.negative_advice = dn_dst_negative_advice,
.link_failure = dn_dst_link_failure,
.update_pmtu = dn_dst_update_pmtu,
.entry_size = sizeof(struct dn_route),
.entries = ATOMIC_INIT(0),
};
static __inline__ unsigned dn_hash(__le16 src, __le16 dst)
{
__u16 tmp = (__u16 __force)(src ^ dst);
tmp ^= (tmp >> 3);
tmp ^= (tmp >> 5);
tmp ^= (tmp >> 10);
return dn_rt_hash_mask & (unsigned)tmp;
}
static inline void dnrt_free(struct dn_route *rt)
{
call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
}
static inline void dnrt_drop(struct dn_route *rt)
{
dst_release(&rt->u.dst);
call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
}
static void dn_dst_check_expire(unsigned long dummy)
{
int i;
struct dn_route *rt, **rtp;
unsigned long now = jiffies;
unsigned long expire = 120 * HZ;
for(i = 0; i <= dn_rt_hash_mask; i++) {
rtp = &dn_rt_hash_table[i].chain;
spin_lock(&dn_rt_hash_table[i].lock);
while((rt=*rtp) != NULL) {
if (atomic_read(&rt->u.dst.__refcnt) ||
(now - rt->u.dst.lastuse) < expire) {
rtp = &rt->u.dst.dn_next;
continue;
}
*rtp = rt->u.dst.dn_next;
rt->u.dst.dn_next = NULL;
dnrt_free(rt);
}
spin_unlock(&dn_rt_hash_table[i].lock);
if ((jiffies - now) > 0)
break;
}
mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ);
}
static int dn_dst_gc(void)
{
struct dn_route *rt, **rtp;
int i;
unsigned long now = jiffies;
unsigned long expire = 10 * HZ;
for(i = 0; i <= dn_rt_hash_mask; i++) {
spin_lock_bh(&dn_rt_hash_table[i].lock);
rtp = &dn_rt_hash_table[i].chain;
while((rt=*rtp) != NULL) {
if (atomic_read(&rt->u.dst.__refcnt) ||
(now - rt->u.dst.lastuse) < expire) {
rtp = &rt->u.dst.dn_next;
continue;
}
*rtp = rt->u.dst.dn_next;
rt->u.dst.dn_next = NULL;
dnrt_drop(rt);
break;
}
spin_unlock_bh(&dn_rt_hash_table[i].lock);
}
return 0;
}
/*
* The decnet standards don't impose a particular minimum mtu, what they
* do insist on is that the routing layer accepts a datagram of at least
* 230 bytes long. Here we have to subtract the routing header length from
* 230 to get the minimum acceptable mtu. If there is no neighbour, then we
* assume the worst and use a long header size.
*
* We update both the mtu and the advertised mss (i.e. the segment size we
* advertise to the other end).
*/
static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu)
{
u32 min_mtu = 230;
struct dn_dev *dn = dst->neighbour ?
(struct dn_dev *)dst->neighbour->dev->dn_ptr : NULL;
if (dn && dn->use_long == 0)
min_mtu -= 6;
else
min_mtu -= 21;
if (dst->metrics[RTAX_MTU-1] > mtu && mtu >= min_mtu) {
if (!(dst_metric_locked(dst, RTAX_MTU))) {
dst->metrics[RTAX_MTU-1] = mtu;
dst_set_expires(dst, dn_rt_mtu_expires);
}
if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
if (dst->metrics[RTAX_ADVMSS-1] > mss)
dst->metrics[RTAX_ADVMSS-1] = mss;
}
}
}
/*
* When a route has been marked obsolete. (e.g. routing cache flush)
*/
static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie)
{
return NULL;
}
static struct dst_entry *dn_dst_negative_advice(struct dst_entry *dst)
{
dst_release(dst);
return NULL;
}
static void dn_dst_link_failure(struct sk_buff *skb)
{
return;
}
static inline int compare_keys(struct flowi *fl1, struct flowi *fl2)
{
return ((fl1->nl_u.dn_u.daddr ^ fl2->nl_u.dn_u.daddr) |
(fl1->nl_u.dn_u.saddr ^ fl2->nl_u.dn_u.saddr) |
(fl1->mark ^ fl2->mark) |
(fl1->nl_u.dn_u.scope ^ fl2->nl_u.dn_u.scope) |
(fl1->oif ^ fl2->oif) |
(fl1->iif ^ fl2->iif)) == 0;
}
static int dn_insert_route(struct dn_route *rt, unsigned hash, struct dn_route **rp)
{
struct dn_route *rth, **rthp;
unsigned long now = jiffies;
rthp = &dn_rt_hash_table[hash].chain;
spin_lock_bh(&dn_rt_hash_table[hash].lock);
while((rth = *rthp) != NULL) {
if (compare_keys(&rth->fl, &rt->fl)) {
/* Put it first */
*rthp = rth->u.dst.dn_next;
rcu_assign_pointer(rth->u.dst.dn_next,
dn_rt_hash_table[hash].chain);
rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);
rth->u.dst.__use++;
dst_hold(&rth->u.dst);
rth->u.dst.lastuse = now;
spin_unlock_bh(&dn_rt_hash_table[hash].lock);
dnrt_drop(rt);
*rp = rth;
return 0;
}
rthp = &rth->u.dst.dn_next;
}
rcu_assign_pointer(rt->u.dst.dn_next, dn_rt_hash_table[hash].chain);
rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);
dst_hold(&rt->u.dst);
rt->u.dst.__use++;
rt->u.dst.lastuse = now;
spin_unlock_bh(&dn_rt_hash_table[hash].lock);
*rp = rt;
return 0;
}
void dn_run_flush(unsigned long dummy)
{
int i;
struct dn_route *rt, *next;
for(i = 0; i < dn_rt_hash_mask; i++) {
spin_lock_bh(&dn_rt_hash_table[i].lock);
if ((rt = xchg(&dn_rt_hash_table[i].chain, NULL)) == NULL)
goto nothing_to_declare;
for(; rt; rt=next) {
next = rt->u.dst.dn_next;
rt->u.dst.dn_next = NULL;
dst_free((struct dst_entry *)rt);
}
nothing_to_declare:
spin_unlock_bh(&dn_rt_hash_table[i].lock);
}
}
static DEFINE_SPINLOCK(dn_rt_flush_lock);
void dn_rt_cache_flush(int delay)
{
unsigned long now = jiffies;
int user_mode = !in_interrupt();
if (delay < 0)
delay = dn_rt_min_delay;
spin_lock_bh(&dn_rt_flush_lock);
if (del_timer(&dn_rt_flush_timer) && delay > 0 && dn_rt_deadline) {
long tmo = (long)(dn_rt_deadline - now);
if (user_mode && tmo < dn_rt_max_delay - dn_rt_min_delay)
tmo = 0;
if (delay > tmo)
delay = tmo;
}
if (delay <= 0) {
spin_unlock_bh(&dn_rt_flush_lock);
dn_run_flush(0);
return;
}
if (dn_rt_deadline == 0)
dn_rt_deadline = now + dn_rt_max_delay;
dn_rt_flush_timer.expires = now + delay;
add_timer(&dn_rt_flush_timer);
spin_unlock_bh(&dn_rt_flush_lock);
}
/**
* dn_return_short - Return a short packet to its sender
* @skb: The packet to return
*
*/
static int dn_return_short(struct sk_buff *skb)
{
struct dn_skb_cb *cb;
unsigned char *ptr;
__le16 *src;
__le16 *dst;
__le16 tmp;
/* Add back headers */
skb_push(skb, skb->data - skb_network_header(skb));
if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
return NET_RX_DROP;
cb = DN_SKB_CB(skb);
/* Skip packet length and point to flags */
ptr = skb->data + 2;
*ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
dst = (__le16 *)ptr;
ptr += 2;
src = (__le16 *)ptr;
ptr += 2;
*ptr = 0; /* Zero hop count */
/* Swap source and destination */
tmp = *src;
*src = *dst;
*dst = tmp;
skb->pkt_type = PACKET_OUTGOING;
dn_rt_finish_output(skb, NULL, NULL);
return NET_RX_SUCCESS;
}
/**
* dn_return_long - Return a long packet to its sender
* @skb: The long format packet to return
*
*/
static int dn_return_long(struct sk_buff *skb)
{
struct dn_skb_cb *cb;
unsigned char *ptr;
unsigned char *src_addr, *dst_addr;
unsigned char tmp[ETH_ALEN];
/* Add back all headers */
skb_push(skb, skb->data - skb_network_header(skb));
if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
return NET_RX_DROP;
cb = DN_SKB_CB(skb);
/* Ignore packet length and point to flags */
ptr = skb->data + 2;
/* Skip padding */
if (*ptr & DN_RT_F_PF) {
char padlen = (*ptr & ~DN_RT_F_PF);
ptr += padlen;
}
*ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
ptr += 2;
dst_addr = ptr;
ptr += 8;
src_addr = ptr;
ptr += 6;
*ptr = 0; /* Zero hop count */
/* Swap source and destination */
memcpy(tmp, src_addr, ETH_ALEN);
memcpy(src_addr, dst_addr, ETH_ALEN);
memcpy(dst_addr, tmp, ETH_ALEN);
skb->pkt_type = PACKET_OUTGOING;
dn_rt_finish_output(skb, dst_addr, src_addr);
return NET_RX_SUCCESS;
}
/**
* dn_route_rx_packet - Try and find a route for an incoming packet
* @skb: The packet to find a route for
*
* Returns: result of input function if route is found, error code otherwise
*/
static int dn_route_rx_packet(struct sk_buff *skb)
{
struct dn_skb_cb *cb = DN_SKB_CB(skb);
int err;
if ((err = dn_route_input(skb)) == 0)
return dst_input(skb);
if (decnet_debug_level & 4) {
char *devname = skb->dev ? skb->dev->name : "???";
struct dn_skb_cb *cb = DN_SKB_CB(skb);
printk(KERN_DEBUG
"DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
(int)cb->rt_flags, devname, skb->len,
dn_ntohs(cb->src), dn_ntohs(cb->dst),
err, skb->pkt_type);
}
if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
switch(cb->rt_flags & DN_RT_PKT_MSK) {
case DN_RT_PKT_SHORT:
return dn_return_short(skb);
case DN_RT_PKT_LONG:
return dn_return_long(skb);
}
}
kfree_skb(skb);
return NET_RX_DROP;
}
static int dn_route_rx_long(struct sk_buff *skb)
{
struct dn_skb_cb *cb = DN_SKB_CB(skb);
unsigned char *ptr = skb->data;
if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
goto drop_it;
skb_pull(skb, 20);
skb_reset_transport_header(skb);
/* Destination info */
ptr += 2;
cb->dst = dn_eth2dn(ptr);
if (memcmp(ptr, dn_hiord_addr, 4) != 0)
goto drop_it;
ptr += 6;
/* Source info */
ptr += 2;
cb->src = dn_eth2dn(ptr);
if (memcmp(ptr, dn_hiord_addr, 4) != 0)
goto drop_it;
ptr += 6;
/* Other junk */
ptr++;
cb->hops = *ptr++; /* Visit Count */
return NF_HOOK(PF_DECnet, NF_DN_PRE_ROUTING, skb, skb->dev, NULL, dn_route_rx_packet);
drop_it:
kfree_skb(skb);
return NET_RX_DROP;
}
static int dn_route_rx_short(struct sk_buff *skb)
{
struct dn_skb_cb *cb = DN_SKB_CB(skb);
unsigned char *ptr = skb->data;
if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
goto drop_it;
skb_pull(skb, 5);
skb_reset_transport_header(skb);
cb->dst = *(__le16 *)ptr;
ptr += 2;
cb->src = *(__le16 *)ptr;
ptr += 2;
cb->hops = *ptr & 0x3f;
return NF_HOOK(PF_DECnet, NF_DN_PRE_ROUTING, skb, skb->dev, NULL, dn_route_rx_packet);
drop_it:
kfree_skb(skb);
return NET_RX_DROP;
}
static int dn_route_discard(struct sk_buff *skb)
{
/*
* I know we drop the packet here, but thats considered success in
* this case
*/
kfree_skb(skb);
return NET_RX_SUCCESS;
}
static int dn_route_ptp_hello(struct sk_buff *skb)
{
dn_dev_hello(skb);
dn_neigh_pointopoint_hello(skb);
return NET_RX_SUCCESS;
}
int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
{
struct dn_skb_cb *cb;
unsigned char flags = 0;
__u16 len = dn_ntohs(*(__le16 *)skb->data);
struct dn_dev *dn = (struct dn_dev *)dev->dn_ptr;
unsigned char padlen = 0;
if (dev->nd_net != &init_net)
goto dump_it;
if (dn == NULL)
goto dump_it;
if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
goto out;
if (!pskb_may_pull(skb, 3))
goto dump_it;
skb_pull(skb, 2);
if (len > skb->len)
goto dump_it;
skb_trim(skb, len);
flags = *skb->data;
cb = DN_SKB_CB(skb);
cb->stamp = jiffies;
cb->iif = dev->ifindex;
/*
* If we have padding, remove it.
*/
if (flags & DN_RT_F_PF) {
padlen = flags & ~DN_RT_F_PF;
if (!pskb_may_pull(skb, padlen + 1))
goto dump_it;
skb_pull(skb, padlen);
flags = *skb->data;
}
skb_reset_network_header(skb);
/*
* Weed out future version DECnet
*/
if (flags & DN_RT_F_VER)
goto dump_it;
cb->rt_flags = flags;
if (decnet_debug_level & 1)
printk(KERN_DEBUG
"dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
(int)flags, (dev) ? dev->name : "???", len, skb->len,
padlen);
if (flags & DN_RT_PKT_CNTL) {
if (unlikely(skb_linearize(skb)))
goto dump_it;
switch(flags & DN_RT_CNTL_MSK) {
case DN_RT_PKT_INIT:
dn_dev_init_pkt(skb);
break;
case DN_RT_PKT_VERI:
dn_dev_veri_pkt(skb);
break;
}
if (dn->parms.state != DN_DEV_S_RU)
goto dump_it;
switch(flags & DN_RT_CNTL_MSK) {
case DN_RT_PKT_HELO:
return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_route_ptp_hello);
case DN_RT_PKT_L1RT:
case DN_RT_PKT_L2RT:
return NF_HOOK(PF_DECnet, NF_DN_ROUTE, skb, skb->dev, NULL, dn_route_discard);
case DN_RT_PKT_ERTH:
return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_neigh_router_hello);
case DN_RT_PKT_EEDH:
return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_neigh_endnode_hello);
}
} else {
if (dn->parms.state != DN_DEV_S_RU)
goto dump_it;
skb_pull(skb, 1); /* Pull flags */
switch(flags & DN_RT_PKT_MSK) {
case DN_RT_PKT_LONG:
return dn_route_rx_long(skb);
case DN_RT_PKT_SHORT:
return dn_route_rx_short(skb);
}
}
dump_it:
kfree_skb(skb);
out:
return NET_RX_DROP;
}
static int dn_output(struct sk_buff *skb)
{
struct dst_entry *dst = skb->dst;
struct dn_route *rt = (struct dn_route *)dst;
struct net_device *dev = dst->dev;
struct dn_skb_cb *cb = DN_SKB_CB(skb);
struct neighbour *neigh;
int err = -EINVAL;
if ((neigh = dst->neighbour) == NULL)
goto error;
skb->dev = dev;
cb->src = rt->rt_saddr;
cb->dst = rt->rt_daddr;
/*
* Always set the Intra-Ethernet bit on all outgoing packets
* originated on this node. Only valid flag from upper layers
* is return-to-sender-requested. Set hop count to 0 too.
*/
cb->rt_flags &= ~DN_RT_F_RQR;
cb->rt_flags |= DN_RT_F_IE;
cb->hops = 0;
return NF_HOOK(PF_DECnet, NF_DN_LOCAL_OUT, skb, NULL, dev, neigh->output);
error:
if (net_ratelimit())
printk(KERN_DEBUG "dn_output: This should not happen\n");
kfree_skb(skb);
return err;
}
static int dn_forward(struct sk_buff *skb)
{
struct dn_skb_cb *cb = DN_SKB_CB(skb);
struct dst_entry *dst = skb->dst;
struct dn_dev *dn_db = dst->dev->dn_ptr;
struct dn_route *rt;
struct neighbour *neigh = dst->neighbour;
int header_len;
#ifdef CONFIG_NETFILTER
struct net_device *dev = skb->dev;
#endif
if (skb->pkt_type != PACKET_HOST)
goto drop;
/* Ensure that we have enough space for headers */
rt = (struct dn_route *)skb->dst;
header_len = dn_db->use_long ? 21 : 6;
if (skb_cow(skb, LL_RESERVED_SPACE(rt->u.dst.dev)+header_len))
goto drop;
/*
* Hop count exceeded.
*/
if (++cb->hops > 30)
goto drop;
skb->dev = rt->u.dst.dev;
/*
* If packet goes out same interface it came in on, then set
* the Intra-Ethernet bit. This has no effect for short
* packets, so we don't need to test for them here.
*/
cb->rt_flags &= ~DN_RT_F_IE;
if (rt->rt_flags & RTCF_DOREDIRECT)
cb->rt_flags |= DN_RT_F_IE;
return NF_HOOK(PF_DECnet, NF_DN_FORWARD, skb, dev, skb->dev, neigh->output);
drop:
kfree_skb(skb);
return NET_RX_DROP;
}
/*
* Drop packet. This is used for endnodes and for
* when we should not be forwarding packets from
* this dest.
*/
static int dn_blackhole(struct sk_buff *skb)
{
kfree_skb(skb);
return NET_RX_DROP;
}
/*
* Used to catch bugs. This should never normally get
* called.
*/
static int dn_rt_bug(struct sk_buff *skb)
{
if (net_ratelimit()) {
struct dn_skb_cb *cb = DN_SKB_CB(skb);
printk(KERN_DEBUG "dn_rt_bug: skb from:%04x to:%04x\n",
dn_ntohs(cb->src), dn_ntohs(cb->dst));
}
kfree_skb(skb);
return NET_RX_BAD;
}
static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
{
struct dn_fib_info *fi = res->fi;
struct net_device *dev = rt->u.dst.dev;
struct neighbour *n;
unsigned mss;
if (fi) {
if (DN_FIB_RES_GW(*res) &&
DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
rt->rt_gateway = DN_FIB_RES_GW(*res);
memcpy(rt->u.dst.metrics, fi->fib_metrics,
sizeof(rt->u.dst.metrics));
}
rt->rt_type = res->type;
if (dev != NULL && rt->u.dst.neighbour == NULL) {
n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
if (IS_ERR(n))
return PTR_ERR(n);
rt->u.dst.neighbour = n;
}
if (rt->u.dst.metrics[RTAX_MTU-1] == 0 ||
rt->u.dst.metrics[RTAX_MTU-1] > rt->u.dst.dev->mtu)
rt->u.dst.metrics[RTAX_MTU-1] = rt->u.dst.dev->mtu;
mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->u.dst));
if (rt->u.dst.metrics[RTAX_ADVMSS-1] == 0 ||
rt->u.dst.metrics[RTAX_ADVMSS-1] > mss)
rt->u.dst.metrics[RTAX_ADVMSS-1] = mss;
return 0;
}
static inline int dn_match_addr(__le16 addr1, __le16 addr2)
{
__u16 tmp = dn_ntohs(addr1) ^ dn_ntohs(addr2);
int match = 16;
while(tmp) {
tmp >>= 1;
match--;
}
return match;
}
static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
{
__le16 saddr = 0;
struct dn_dev *dn_db = dev->dn_ptr;
struct dn_ifaddr *ifa;
int best_match = 0;
int ret;
read_lock(&dev_base_lock);
for(ifa = dn_db->ifa_list; ifa; ifa = ifa->ifa_next) {
if (ifa->ifa_scope > scope)
continue;
if (!daddr) {
saddr = ifa->ifa_local;
break;
}
ret = dn_match_addr(daddr, ifa->ifa_local);
if (ret > best_match)
saddr = ifa->ifa_local;
if (best_match == 0)
saddr = ifa->ifa_local;
}
read_unlock(&dev_base_lock);
return saddr;
}
static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
{
return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
}
static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
{
__le16 mask = dnet_make_mask(res->prefixlen);
return (daddr&~mask)|res->fi->fib_nh->nh_gw;
}
static int dn_route_output_slow(struct dst_entry **pprt, const struct flowi *oldflp, int try_hard)
{
struct flowi fl = { .nl_u = { .dn_u =
{ .daddr = oldflp->fld_dst,
.saddr = oldflp->fld_src,
.scope = RT_SCOPE_UNIVERSE,
} },
.mark = oldflp->mark,
.iif = init_net.loopback_dev->ifindex,
.oif = oldflp->oif };
struct dn_route *rt = NULL;
struct net_device *dev_out = NULL, *dev;
struct neighbour *neigh = NULL;
unsigned hash;
unsigned flags = 0;
struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
int err;
int free_res = 0;
__le16 gateway = 0;
if (decnet_debug_level & 16)
printk(KERN_DEBUG
"dn_route_output_slow: dst=%04x src=%04x mark=%d"
" iif=%d oif=%d\n", dn_ntohs(oldflp->fld_dst),
dn_ntohs(oldflp->fld_src),
oldflp->mark, init_net.loopback_dev->ifindex, oldflp->oif);
/* If we have an output interface, verify its a DECnet device */
if (oldflp->oif) {
dev_out = dev_get_by_index(&init_net, oldflp->oif);
err = -ENODEV;
if (dev_out && dev_out->dn_ptr == NULL) {
dev_put(dev_out);
dev_out = NULL;
}
if (dev_out == NULL)
goto out;
}
/* If we have a source address, verify that its a local address */
if (oldflp->fld_src) {
err = -EADDRNOTAVAIL;
if (dev_out) {
if (dn_dev_islocal(dev_out, oldflp->fld_src))
goto source_ok;
dev_put(dev_out);
goto out;
}
read_lock(&dev_base_lock);
for_each_netdev(&init_net, dev) {
if (!dev->dn_ptr)
continue;
if (!dn_dev_islocal(dev, oldflp->fld_src))
continue;
if ((dev->flags & IFF_LOOPBACK) &&
oldflp->fld_dst &&
!dn_dev_islocal(dev, oldflp->fld_dst))
continue;
dev_out = dev;
break;
}
read_unlock(&dev_base_lock);
if (dev_out == NULL)
goto out;
dev_hold(dev_out);
source_ok:
;
}
/* No destination? Assume its local */
if (!fl.fld_dst) {
fl.fld_dst = fl.fld_src;
err = -EADDRNOTAVAIL;
if (dev_out)
dev_put(dev_out);
dev_out = init_net.loopback_dev;
dev_hold(dev_out);
if (!fl.fld_dst) {
fl.fld_dst =
fl.fld_src = dnet_select_source(dev_out, 0,
RT_SCOPE_HOST);
if (!fl.fld_dst)
goto out;
}
fl.oif = init_net.loopback_dev->ifindex;
res.type = RTN_LOCAL;
goto make_route;
}
if (decnet_debug_level & 16)
printk(KERN_DEBUG
"dn_route_output_slow: initial checks complete."
" dst=%o4x src=%04x oif=%d try_hard=%d\n",
dn_ntohs(fl.fld_dst), dn_ntohs(fl.fld_src),
fl.oif, try_hard);
/*
* N.B. If the kernel is compiled without router support then
* dn_fib_lookup() will evaluate to non-zero so this if () block
* will always be executed.
*/
err = -ESRCH;
if (try_hard || (err = dn_fib_lookup(&fl, &res)) != 0) {
struct dn_dev *dn_db;
if (err != -ESRCH)
goto out;
/*
* Here the fallback is basically the standard algorithm for
* routing in endnodes which is described in the DECnet routing
* docs
*
* If we are not trying hard, look in neighbour cache.
* The result is tested to ensure that if a specific output
* device/source address was requested, then we honour that
* here
*/