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route.c
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/*
* Linux INET6 implementation
* FIB front-end.
*
* Authors:
* Pedro Roque <[email protected]>
*
* $Id: route.c,v 1.56 2001/10/31 21:55:55 davem Exp $
*
* 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 (at your option) any later version.
*/
/* Changes:
*
* YOSHIFUJI Hideaki @USAGI
* reworked default router selection.
* - respect outgoing interface
* - select from (probably) reachable routers (i.e.
* routers in REACHABLE, STALE, DELAY or PROBE states).
* - always select the same router if it is (probably)
* reachable. otherwise, round-robin the list.
* Ville Nuorvala
* Fixed routing subtrees.
*/
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/times.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/route.h>
#include <linux/netdevice.h>
#include <linux/in6.h>
#include <linux/init.h>
#include <linux/if_arp.h>
#ifdef CONFIG_PROC_FS
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#endif
#include <net/snmp.h>
#include <net/ipv6.h>
#include <net/ip6_fib.h>
#include <net/ip6_route.h>
#include <net/ndisc.h>
#include <net/addrconf.h>
#include <net/tcp.h>
#include <linux/rtnetlink.h>
#include <net/dst.h>
#include <net/xfrm.h>
#include <net/netevent.h>
#include <net/netlink.h>
#include <asm/uaccess.h>
#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>
#endif
/* Set to 3 to get tracing. */
#define RT6_DEBUG 2
#if RT6_DEBUG >= 3
#define RDBG(x) printk x
#define RT6_TRACE(x...) printk(KERN_DEBUG x)
#else
#define RDBG(x)
#define RT6_TRACE(x...) do { ; } while (0)
#endif
#define CLONE_OFFLINK_ROUTE 0
static int ip6_rt_max_size = 4096;
static int ip6_rt_gc_min_interval = HZ / 2;
static int ip6_rt_gc_timeout = 60*HZ;
int ip6_rt_gc_interval = 30*HZ;
static int ip6_rt_gc_elasticity = 9;
static int ip6_rt_mtu_expires = 10*60*HZ;
static int ip6_rt_min_advmss = IPV6_MIN_MTU - 20 - 40;
static struct rt6_info * ip6_rt_copy(struct rt6_info *ort);
static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie);
static struct dst_entry *ip6_negative_advice(struct dst_entry *);
static void ip6_dst_destroy(struct dst_entry *);
static void ip6_dst_ifdown(struct dst_entry *,
struct net_device *dev, int how);
static int ip6_dst_gc(void);
static int ip6_pkt_discard(struct sk_buff *skb);
static int ip6_pkt_discard_out(struct sk_buff *skb);
static void ip6_link_failure(struct sk_buff *skb);
static void ip6_rt_update_pmtu(struct dst_entry *dst, u32 mtu);
#ifdef CONFIG_IPV6_ROUTE_INFO
static struct rt6_info *rt6_add_route_info(struct in6_addr *prefix, int prefixlen,
struct in6_addr *gwaddr, int ifindex,
unsigned pref);
static struct rt6_info *rt6_get_route_info(struct in6_addr *prefix, int prefixlen,
struct in6_addr *gwaddr, int ifindex);
#endif
static struct dst_ops ip6_dst_ops = {
.family = AF_INET6,
.protocol = __constant_htons(ETH_P_IPV6),
.gc = ip6_dst_gc,
.gc_thresh = 1024,
.check = ip6_dst_check,
.destroy = ip6_dst_destroy,
.ifdown = ip6_dst_ifdown,
.negative_advice = ip6_negative_advice,
.link_failure = ip6_link_failure,
.update_pmtu = ip6_rt_update_pmtu,
.entry_size = sizeof(struct rt6_info),
};
struct rt6_info ip6_null_entry = {
.u = {
.dst = {
.__refcnt = ATOMIC_INIT(1),
.__use = 1,
.dev = &loopback_dev,
.obsolete = -1,
.error = -ENETUNREACH,
.metrics = { [RTAX_HOPLIMIT - 1] = 255, },
.input = ip6_pkt_discard,
.output = ip6_pkt_discard_out,
.ops = &ip6_dst_ops,
.path = (struct dst_entry*)&ip6_null_entry,
}
},
.rt6i_flags = (RTF_REJECT | RTF_NONEXTHOP),
.rt6i_metric = ~(u32) 0,
.rt6i_ref = ATOMIC_INIT(1),
};
#ifdef CONFIG_IPV6_MULTIPLE_TABLES
static int ip6_pkt_prohibit(struct sk_buff *skb);
static int ip6_pkt_prohibit_out(struct sk_buff *skb);
static int ip6_pkt_blk_hole(struct sk_buff *skb);
struct rt6_info ip6_prohibit_entry = {
.u = {
.dst = {
.__refcnt = ATOMIC_INIT(1),
.__use = 1,
.dev = &loopback_dev,
.obsolete = -1,
.error = -EACCES,
.metrics = { [RTAX_HOPLIMIT - 1] = 255, },
.input = ip6_pkt_prohibit,
.output = ip6_pkt_prohibit_out,
.ops = &ip6_dst_ops,
.path = (struct dst_entry*)&ip6_prohibit_entry,
}
},
.rt6i_flags = (RTF_REJECT | RTF_NONEXTHOP),
.rt6i_metric = ~(u32) 0,
.rt6i_ref = ATOMIC_INIT(1),
};
struct rt6_info ip6_blk_hole_entry = {
.u = {
.dst = {
.__refcnt = ATOMIC_INIT(1),
.__use = 1,
.dev = &loopback_dev,
.obsolete = -1,
.error = -EINVAL,
.metrics = { [RTAX_HOPLIMIT - 1] = 255, },
.input = ip6_pkt_blk_hole,
.output = ip6_pkt_blk_hole,
.ops = &ip6_dst_ops,
.path = (struct dst_entry*)&ip6_blk_hole_entry,
}
},
.rt6i_flags = (RTF_REJECT | RTF_NONEXTHOP),
.rt6i_metric = ~(u32) 0,
.rt6i_ref = ATOMIC_INIT(1),
};
#endif
/* allocate dst with ip6_dst_ops */
static __inline__ struct rt6_info *ip6_dst_alloc(void)
{
return (struct rt6_info *)dst_alloc(&ip6_dst_ops);
}
static void ip6_dst_destroy(struct dst_entry *dst)
{
struct rt6_info *rt = (struct rt6_info *)dst;
struct inet6_dev *idev = rt->rt6i_idev;
if (idev != NULL) {
rt->rt6i_idev = NULL;
in6_dev_put(idev);
}
}
static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
int how)
{
struct rt6_info *rt = (struct rt6_info *)dst;
struct inet6_dev *idev = rt->rt6i_idev;
if (dev != &loopback_dev && idev != NULL && idev->dev == dev) {
struct inet6_dev *loopback_idev = in6_dev_get(&loopback_dev);
if (loopback_idev != NULL) {
rt->rt6i_idev = loopback_idev;
in6_dev_put(idev);
}
}
}
static __inline__ int rt6_check_expired(const struct rt6_info *rt)
{
return (rt->rt6i_flags & RTF_EXPIRES &&
time_after(jiffies, rt->rt6i_expires));
}
static inline int rt6_need_strict(struct in6_addr *daddr)
{
return (ipv6_addr_type(daddr) &
(IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL));
}
/*
* Route lookup. Any table->tb6_lock is implied.
*/
static __inline__ struct rt6_info *rt6_device_match(struct rt6_info *rt,
int oif,
int strict)
{
struct rt6_info *local = NULL;
struct rt6_info *sprt;
if (oif) {
for (sprt = rt; sprt; sprt = sprt->u.dst.rt6_next) {
struct net_device *dev = sprt->rt6i_dev;
if (dev->ifindex == oif)
return sprt;
if (dev->flags & IFF_LOOPBACK) {
if (sprt->rt6i_idev == NULL ||
sprt->rt6i_idev->dev->ifindex != oif) {
if (strict && oif)
continue;
if (local && (!oif ||
local->rt6i_idev->dev->ifindex == oif))
continue;
}
local = sprt;
}
}
if (local)
return local;
if (strict)
return &ip6_null_entry;
}
return rt;
}
#ifdef CONFIG_IPV6_ROUTER_PREF
static void rt6_probe(struct rt6_info *rt)
{
struct neighbour *neigh = rt ? rt->rt6i_nexthop : NULL;
/*
* Okay, this does not seem to be appropriate
* for now, however, we need to check if it
* is really so; aka Router Reachability Probing.
*
* Router Reachability Probe MUST be rate-limited
* to no more than one per minute.
*/
if (!neigh || (neigh->nud_state & NUD_VALID))
return;
read_lock_bh(&neigh->lock);
if (!(neigh->nud_state & NUD_VALID) &&
time_after(jiffies, neigh->updated + rt->rt6i_idev->cnf.rtr_probe_interval)) {
struct in6_addr mcaddr;
struct in6_addr *target;
neigh->updated = jiffies;
read_unlock_bh(&neigh->lock);
target = (struct in6_addr *)&neigh->primary_key;
addrconf_addr_solict_mult(target, &mcaddr);
ndisc_send_ns(rt->rt6i_dev, NULL, target, &mcaddr, NULL);
} else
read_unlock_bh(&neigh->lock);
}
#else
static inline void rt6_probe(struct rt6_info *rt)
{
return;
}
#endif
/*
* Default Router Selection (RFC 2461 6.3.6)
*/
static int inline rt6_check_dev(struct rt6_info *rt, int oif)
{
struct net_device *dev = rt->rt6i_dev;
int ret = 0;
if (!oif)
return 2;
if (dev->flags & IFF_LOOPBACK) {
if (!WARN_ON(rt->rt6i_idev == NULL) &&
rt->rt6i_idev->dev->ifindex == oif)
ret = 1;
else
return 0;
}
if (dev->ifindex == oif)
return 2;
return ret;
}
static int inline rt6_check_neigh(struct rt6_info *rt)
{
struct neighbour *neigh = rt->rt6i_nexthop;
int m = 0;
if (rt->rt6i_flags & RTF_NONEXTHOP ||
!(rt->rt6i_flags & RTF_GATEWAY))
m = 1;
else if (neigh) {
read_lock_bh(&neigh->lock);
if (neigh->nud_state & NUD_VALID)
m = 2;
else if (!(neigh->nud_state & NUD_FAILED))
m = 1;
read_unlock_bh(&neigh->lock);
}
return m;
}
static int rt6_score_route(struct rt6_info *rt, int oif,
int strict)
{
int m, n;
m = rt6_check_dev(rt, oif);
if (!m && (strict & RT6_LOOKUP_F_IFACE))
return -1;
#ifdef CONFIG_IPV6_ROUTER_PREF
m |= IPV6_DECODE_PREF(IPV6_EXTRACT_PREF(rt->rt6i_flags)) << 2;
#endif
n = rt6_check_neigh(rt);
if (!n && (strict & RT6_LOOKUP_F_REACHABLE))
return -1;
return m;
}
static struct rt6_info *rt6_select(struct rt6_info **head, int oif,
int strict)
{
struct rt6_info *match = NULL, *last = NULL;
struct rt6_info *rt, *rt0 = *head;
u32 metric;
int mpri = -1;
RT6_TRACE("%s(head=%p(*head=%p), oif=%d)\n",
__FUNCTION__, head, head ? *head : NULL, oif);
for (rt = rt0, metric = rt0->rt6i_metric;
rt && rt->rt6i_metric == metric && (!last || rt != rt0);
rt = rt->u.dst.rt6_next) {
int m;
if (rt6_check_expired(rt))
continue;
last = rt;
m = rt6_score_route(rt, oif, strict);
if (m < 0)
continue;
if (m > mpri) {
if (strict & RT6_LOOKUP_F_REACHABLE)
rt6_probe(match);
match = rt;
mpri = m;
} else if (strict & RT6_LOOKUP_F_REACHABLE) {
rt6_probe(rt);
}
}
if (!match &&
(strict & RT6_LOOKUP_F_REACHABLE) &&
last && last != rt0) {
/* no entries matched; do round-robin */
static DEFINE_SPINLOCK(lock);
spin_lock(&lock);
*head = rt0->u.dst.rt6_next;
rt0->u.dst.rt6_next = last->u.dst.rt6_next;
last->u.dst.rt6_next = rt0;
spin_unlock(&lock);
}
RT6_TRACE("%s() => %p, score=%d\n",
__FUNCTION__, match, mpri);
return (match ? match : &ip6_null_entry);
}
#ifdef CONFIG_IPV6_ROUTE_INFO
int rt6_route_rcv(struct net_device *dev, u8 *opt, int len,
struct in6_addr *gwaddr)
{
struct route_info *rinfo = (struct route_info *) opt;
struct in6_addr prefix_buf, *prefix;
unsigned int pref;
u32 lifetime;
struct rt6_info *rt;
if (len < sizeof(struct route_info)) {
return -EINVAL;
}
/* Sanity check for prefix_len and length */
if (rinfo->length > 3) {
return -EINVAL;
} else if (rinfo->prefix_len > 128) {
return -EINVAL;
} else if (rinfo->prefix_len > 64) {
if (rinfo->length < 2) {
return -EINVAL;
}
} else if (rinfo->prefix_len > 0) {
if (rinfo->length < 1) {
return -EINVAL;
}
}
pref = rinfo->route_pref;
if (pref == ICMPV6_ROUTER_PREF_INVALID)
pref = ICMPV6_ROUTER_PREF_MEDIUM;
lifetime = ntohl(rinfo->lifetime);
if (lifetime == 0xffffffff) {
/* infinity */
} else if (lifetime > 0x7fffffff/HZ) {
/* Avoid arithmetic overflow */
lifetime = 0x7fffffff/HZ - 1;
}
if (rinfo->length == 3)
prefix = (struct in6_addr *)rinfo->prefix;
else {
/* this function is safe */
ipv6_addr_prefix(&prefix_buf,
(struct in6_addr *)rinfo->prefix,
rinfo->prefix_len);
prefix = &prefix_buf;
}
rt = rt6_get_route_info(prefix, rinfo->prefix_len, gwaddr, dev->ifindex);
if (rt && !lifetime) {
ip6_del_rt(rt);
rt = NULL;
}
if (!rt && lifetime)
rt = rt6_add_route_info(prefix, rinfo->prefix_len, gwaddr, dev->ifindex,
pref);
else if (rt)
rt->rt6i_flags = RTF_ROUTEINFO |
(rt->rt6i_flags & ~RTF_PREF_MASK) | RTF_PREF(pref);
if (rt) {
if (lifetime == 0xffffffff) {
rt->rt6i_flags &= ~RTF_EXPIRES;
} else {
rt->rt6i_expires = jiffies + HZ * lifetime;
rt->rt6i_flags |= RTF_EXPIRES;
}
dst_release(&rt->u.dst);
}
return 0;
}
#endif
#define BACKTRACK(saddr) \
do { \
if (rt == &ip6_null_entry) { \
struct fib6_node *pn; \
while (1) { \
if (fn->fn_flags & RTN_TL_ROOT) \
goto out; \
pn = fn->parent; \
if (FIB6_SUBTREE(pn) && FIB6_SUBTREE(pn) != fn) \
fn = fib6_lookup(FIB6_SUBTREE(pn), NULL, saddr); \
else \
fn = pn; \
if (fn->fn_flags & RTN_RTINFO) \
goto restart; \
} \
} \
} while(0)
static struct rt6_info *ip6_pol_route_lookup(struct fib6_table *table,
struct flowi *fl, int flags)
{
struct fib6_node *fn;
struct rt6_info *rt;
read_lock_bh(&table->tb6_lock);
fn = fib6_lookup(&table->tb6_root, &fl->fl6_dst, &fl->fl6_src);
restart:
rt = fn->leaf;
rt = rt6_device_match(rt, fl->oif, flags);
BACKTRACK(&fl->fl6_src);
out:
dst_hold(&rt->u.dst);
read_unlock_bh(&table->tb6_lock);
rt->u.dst.lastuse = jiffies;
rt->u.dst.__use++;
return rt;
}
struct rt6_info *rt6_lookup(struct in6_addr *daddr, struct in6_addr *saddr,
int oif, int strict)
{
struct flowi fl = {
.oif = oif,
.nl_u = {
.ip6_u = {
.daddr = *daddr,
},
},
};
struct dst_entry *dst;
int flags = strict ? RT6_LOOKUP_F_IFACE : 0;
if (saddr) {
memcpy(&fl.fl6_src, saddr, sizeof(*saddr));
flags |= RT6_LOOKUP_F_HAS_SADDR;
}
dst = fib6_rule_lookup(&fl, flags, ip6_pol_route_lookup);
if (dst->error == 0)
return (struct rt6_info *) dst;
dst_release(dst);
return NULL;
}
/* ip6_ins_rt is called with FREE table->tb6_lock.
It takes new route entry, the addition fails by any reason the
route is freed. In any case, if caller does not hold it, it may
be destroyed.
*/
static int __ip6_ins_rt(struct rt6_info *rt, struct nl_info *info)
{
int err;
struct fib6_table *table;
table = rt->rt6i_table;
write_lock_bh(&table->tb6_lock);
err = fib6_add(&table->tb6_root, rt, info);
write_unlock_bh(&table->tb6_lock);
return err;
}
int ip6_ins_rt(struct rt6_info *rt)
{
return __ip6_ins_rt(rt, NULL);
}
static struct rt6_info *rt6_alloc_cow(struct rt6_info *ort, struct in6_addr *daddr,
struct in6_addr *saddr)
{
struct rt6_info *rt;
/*
* Clone the route.
*/
rt = ip6_rt_copy(ort);
if (rt) {
if (!(rt->rt6i_flags&RTF_GATEWAY)) {
if (rt->rt6i_dst.plen != 128 &&
ipv6_addr_equal(&rt->rt6i_dst.addr, daddr))
rt->rt6i_flags |= RTF_ANYCAST;
ipv6_addr_copy(&rt->rt6i_gateway, daddr);
}
ipv6_addr_copy(&rt->rt6i_dst.addr, daddr);
rt->rt6i_dst.plen = 128;
rt->rt6i_flags |= RTF_CACHE;
rt->u.dst.flags |= DST_HOST;
#ifdef CONFIG_IPV6_SUBTREES
if (rt->rt6i_src.plen && saddr) {
ipv6_addr_copy(&rt->rt6i_src.addr, saddr);
rt->rt6i_src.plen = 128;
}
#endif
rt->rt6i_nexthop = ndisc_get_neigh(rt->rt6i_dev, &rt->rt6i_gateway);
}
return rt;
}
static struct rt6_info *rt6_alloc_clone(struct rt6_info *ort, struct in6_addr *daddr)
{
struct rt6_info *rt = ip6_rt_copy(ort);
if (rt) {
ipv6_addr_copy(&rt->rt6i_dst.addr, daddr);
rt->rt6i_dst.plen = 128;
rt->rt6i_flags |= RTF_CACHE;
rt->u.dst.flags |= DST_HOST;
rt->rt6i_nexthop = neigh_clone(ort->rt6i_nexthop);
}
return rt;
}
static struct rt6_info *ip6_pol_route_input(struct fib6_table *table,
struct flowi *fl, int flags)
{
struct fib6_node *fn;
struct rt6_info *rt, *nrt;
int strict = 0;
int attempts = 3;
int err;
int reachable = ipv6_devconf.forwarding ? 0 : RT6_LOOKUP_F_REACHABLE;
strict |= flags & RT6_LOOKUP_F_IFACE;
relookup:
read_lock_bh(&table->tb6_lock);
restart_2:
fn = fib6_lookup(&table->tb6_root, &fl->fl6_dst, &fl->fl6_src);
restart:
rt = rt6_select(&fn->leaf, fl->iif, strict | reachable);
BACKTRACK(&fl->fl6_src);
if (rt == &ip6_null_entry ||
rt->rt6i_flags & RTF_CACHE)
goto out;
dst_hold(&rt->u.dst);
read_unlock_bh(&table->tb6_lock);
if (!rt->rt6i_nexthop && !(rt->rt6i_flags & RTF_NONEXTHOP))
nrt = rt6_alloc_cow(rt, &fl->fl6_dst, &fl->fl6_src);
else {
#if CLONE_OFFLINK_ROUTE
nrt = rt6_alloc_clone(rt, &fl->fl6_dst);
#else
goto out2;
#endif
}
dst_release(&rt->u.dst);
rt = nrt ? : &ip6_null_entry;
dst_hold(&rt->u.dst);
if (nrt) {
err = ip6_ins_rt(nrt);
if (!err)
goto out2;
}
if (--attempts <= 0)
goto out2;
/*
* Race condition! In the gap, when table->tb6_lock was
* released someone could insert this route. Relookup.
*/
dst_release(&rt->u.dst);
goto relookup;
out:
if (reachable) {
reachable = 0;
goto restart_2;
}
dst_hold(&rt->u.dst);
read_unlock_bh(&table->tb6_lock);
out2:
rt->u.dst.lastuse = jiffies;
rt->u.dst.__use++;
return rt;
}
void ip6_route_input(struct sk_buff *skb)
{
struct ipv6hdr *iph = skb->nh.ipv6h;
int flags = RT6_LOOKUP_F_HAS_SADDR;
struct flowi fl = {
.iif = skb->dev->ifindex,
.nl_u = {
.ip6_u = {
.daddr = iph->daddr,
.saddr = iph->saddr,
.flowlabel = (* (__be32 *) iph)&IPV6_FLOWINFO_MASK,
},
},
.mark = skb->mark,
.proto = iph->nexthdr,
};
if (rt6_need_strict(&iph->daddr))
flags |= RT6_LOOKUP_F_IFACE;
skb->dst = fib6_rule_lookup(&fl, flags, ip6_pol_route_input);
}
static struct rt6_info *ip6_pol_route_output(struct fib6_table *table,
struct flowi *fl, int flags)
{
struct fib6_node *fn;
struct rt6_info *rt, *nrt;
int strict = 0;
int attempts = 3;
int err;
int reachable = ipv6_devconf.forwarding ? 0 : RT6_LOOKUP_F_REACHABLE;
strict |= flags & RT6_LOOKUP_F_IFACE;
relookup:
read_lock_bh(&table->tb6_lock);
restart_2:
fn = fib6_lookup(&table->tb6_root, &fl->fl6_dst, &fl->fl6_src);
restart:
rt = rt6_select(&fn->leaf, fl->oif, strict | reachable);
BACKTRACK(&fl->fl6_src);
if (rt == &ip6_null_entry ||
rt->rt6i_flags & RTF_CACHE)
goto out;
dst_hold(&rt->u.dst);
read_unlock_bh(&table->tb6_lock);
if (!rt->rt6i_nexthop && !(rt->rt6i_flags & RTF_NONEXTHOP))
nrt = rt6_alloc_cow(rt, &fl->fl6_dst, &fl->fl6_src);
else {
#if CLONE_OFFLINK_ROUTE
nrt = rt6_alloc_clone(rt, &fl->fl6_dst);
#else
goto out2;
#endif
}
dst_release(&rt->u.dst);
rt = nrt ? : &ip6_null_entry;
dst_hold(&rt->u.dst);
if (nrt) {
err = ip6_ins_rt(nrt);
if (!err)
goto out2;
}
if (--attempts <= 0)
goto out2;
/*
* Race condition! In the gap, when table->tb6_lock was
* released someone could insert this route. Relookup.
*/
dst_release(&rt->u.dst);
goto relookup;
out:
if (reachable) {
reachable = 0;
goto restart_2;
}
dst_hold(&rt->u.dst);
read_unlock_bh(&table->tb6_lock);
out2:
rt->u.dst.lastuse = jiffies;
rt->u.dst.__use++;
return rt;
}
struct dst_entry * ip6_route_output(struct sock *sk, struct flowi *fl)
{
int flags = 0;
if (rt6_need_strict(&fl->fl6_dst))
flags |= RT6_LOOKUP_F_IFACE;
if (!ipv6_addr_any(&fl->fl6_src))
flags |= RT6_LOOKUP_F_HAS_SADDR;
return fib6_rule_lookup(fl, flags, ip6_pol_route_output);
}
/*
* Destination cache support functions
*/
static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie)
{
struct rt6_info *rt;
rt = (struct rt6_info *) dst;
if (rt && rt->rt6i_node && (rt->rt6i_node->fn_sernum == cookie))
return dst;
return NULL;
}
static struct dst_entry *ip6_negative_advice(struct dst_entry *dst)
{
struct rt6_info *rt = (struct rt6_info *) dst;
if (rt) {
if (rt->rt6i_flags & RTF_CACHE)
ip6_del_rt(rt);
else
dst_release(dst);
}
return NULL;
}
static void ip6_link_failure(struct sk_buff *skb)
{
struct rt6_info *rt;
icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0, skb->dev);
rt = (struct rt6_info *) skb->dst;
if (rt) {
if (rt->rt6i_flags&RTF_CACHE) {
dst_set_expires(&rt->u.dst, 0);
rt->rt6i_flags |= RTF_EXPIRES;
} else if (rt->rt6i_node && (rt->rt6i_flags & RTF_DEFAULT))
rt->rt6i_node->fn_sernum = -1;
}
}
static void ip6_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
{
struct rt6_info *rt6 = (struct rt6_info*)dst;
if (mtu < dst_mtu(dst) && rt6->rt6i_dst.plen == 128) {
rt6->rt6i_flags |= RTF_MODIFIED;
if (mtu < IPV6_MIN_MTU) {
mtu = IPV6_MIN_MTU;
dst->metrics[RTAX_FEATURES-1] |= RTAX_FEATURE_ALLFRAG;
}
dst->metrics[RTAX_MTU-1] = mtu;
call_netevent_notifiers(NETEVENT_PMTU_UPDATE, dst);
}
}
static int ipv6_get_mtu(struct net_device *dev);
static inline unsigned int ipv6_advmss(unsigned int mtu)
{
mtu -= sizeof(struct ipv6hdr) + sizeof(struct tcphdr);
if (mtu < ip6_rt_min_advmss)
mtu = ip6_rt_min_advmss;
/*
* Maximal non-jumbo IPv6 payload is IPV6_MAXPLEN and
* corresponding MSS is IPV6_MAXPLEN - tcp_header_size.
* IPV6_MAXPLEN is also valid and means: "any MSS,
* rely only on pmtu discovery"
*/
if (mtu > IPV6_MAXPLEN - sizeof(struct tcphdr))
mtu = IPV6_MAXPLEN;
return mtu;
}
static struct dst_entry *ndisc_dst_gc_list;
static DEFINE_SPINLOCK(ndisc_lock);
struct dst_entry *ndisc_dst_alloc(struct net_device *dev,
struct neighbour *neigh,
struct in6_addr *addr,
int (*output)(struct sk_buff *))
{
struct rt6_info *rt;
struct inet6_dev *idev = in6_dev_get(dev);
if (unlikely(idev == NULL))
return NULL;
rt = ip6_dst_alloc();
if (unlikely(rt == NULL)) {
in6_dev_put(idev);
goto out;
}
dev_hold(dev);
if (neigh)
neigh_hold(neigh);
else
neigh = ndisc_get_neigh(dev, addr);
rt->rt6i_dev = dev;
rt->rt6i_idev = idev;
rt->rt6i_nexthop = neigh;
atomic_set(&rt->u.dst.__refcnt, 1);
rt->u.dst.metrics[RTAX_HOPLIMIT-1] = 255;
rt->u.dst.metrics[RTAX_MTU-1] = ipv6_get_mtu(rt->rt6i_dev);
rt->u.dst.metrics[RTAX_ADVMSS-1] = ipv6_advmss(dst_mtu(&rt->u.dst));
rt->u.dst.output = output;
#if 0 /* there's no chance to use these for ndisc */
rt->u.dst.flags = ipv6_addr_type(addr) & IPV6_ADDR_UNICAST
? DST_HOST
: 0;
ipv6_addr_copy(&rt->rt6i_dst.addr, addr);
rt->rt6i_dst.plen = 128;
#endif
spin_lock_bh(&ndisc_lock);
rt->u.dst.next = ndisc_dst_gc_list;
ndisc_dst_gc_list = &rt->u.dst;
spin_unlock_bh(&ndisc_lock);
fib6_force_start_gc();
out:
return &rt->u.dst;
}
int ndisc_dst_gc(int *more)
{
struct dst_entry *dst, *next, **pprev;
int freed;
next = NULL;
freed = 0;
spin_lock_bh(&ndisc_lock);
pprev = &ndisc_dst_gc_list;
while ((dst = *pprev) != NULL) {
if (!atomic_read(&dst->__refcnt)) {
*pprev = dst->next;
dst_free(dst);
freed++;
} else {
pprev = &dst->next;
(*more)++;
}
}
spin_unlock_bh(&ndisc_lock);
return freed;
}
static int ip6_dst_gc(void)
{
static unsigned expire = 30*HZ;
static unsigned long last_gc;
unsigned long now = jiffies;
if (time_after(last_gc + ip6_rt_gc_min_interval, now) &&
atomic_read(&ip6_dst_ops.entries) <= ip6_rt_max_size)
goto out;
expire++;
fib6_run_gc(expire);
last_gc = now;
if (atomic_read(&ip6_dst_ops.entries) < ip6_dst_ops.gc_thresh)
expire = ip6_rt_gc_timeout>>1;
out:
expire -= expire>>ip6_rt_gc_elasticity;
return (atomic_read(&ip6_dst_ops.entries) > ip6_rt_max_size);