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linux/net/ipv4/fib_semantics.c
Herbert Xu e5ed639913 [IPV4]: Replace __in_dev_get with __in_dev_get_rcu/rtnl 
The following patch renames __in_dev_get() to __in_dev_get_rtnl() and
introduces __in_dev_get_rcu() to cover the second case.

1) RCU with refcnt should use in_dev_get().
2) RCU without refcnt should use __in_dev_get_rcu().
3) All others must hold RTNL and use __in_dev_get_rtnl().

There is one exception in net/ipv4/route.c which is in fact a pre-existing
race condition.  I've marked it as such so that we remember to fix it.

This patch is based on suggestions and prior work by Suzanne Wood and
Paul McKenney.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-03 14:35:55 -07:00

1340 lines
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/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* IPv4 Forwarding Information Base: semantics.
*
* Version: $Id: fib_semantics.c,v 1.19 2002/01/12 07:54:56 davem Exp $
*
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
* 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.
*/
#include <linux/config.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/errno.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/proc_fs.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/init.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/route.h>
#include <net/tcp.h>
#include <net/sock.h>
#include <net/ip_fib.h>
#include <net/ip_mp_alg.h>
#include "fib_lookup.h"
#define FSprintk(a...)
static DEFINE_RWLOCK(fib_info_lock);
static struct hlist_head *fib_info_hash;
static struct hlist_head *fib_info_laddrhash;
static unsigned int fib_hash_size;
static unsigned int fib_info_cnt;
#define DEVINDEX_HASHBITS 8
#define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
#ifdef CONFIG_IP_ROUTE_MULTIPATH
static DEFINE_SPINLOCK(fib_multipath_lock);
#define for_nexthops(fi) { int nhsel; const struct fib_nh * nh; \
for (nhsel=0, nh = (fi)->fib_nh; nhsel < (fi)->fib_nhs; nh++, nhsel++)
#define change_nexthops(fi) { int nhsel; struct fib_nh * nh; \
for (nhsel=0, nh = (struct fib_nh*)((fi)->fib_nh); nhsel < (fi)->fib_nhs; nh++, nhsel++)
#else /* CONFIG_IP_ROUTE_MULTIPATH */
/* Hope, that gcc will optimize it to get rid of dummy loop */
#define for_nexthops(fi) { int nhsel=0; const struct fib_nh * nh = (fi)->fib_nh; \
for (nhsel=0; nhsel < 1; nhsel++)
#define change_nexthops(fi) { int nhsel=0; struct fib_nh * nh = (struct fib_nh*)((fi)->fib_nh); \
for (nhsel=0; nhsel < 1; nhsel++)
#endif /* CONFIG_IP_ROUTE_MULTIPATH */
#define endfor_nexthops(fi) }
static struct
{
int error;
u8 scope;
} fib_props[RTA_MAX + 1] = {
{
.error = 0,
.scope = RT_SCOPE_NOWHERE,
}, /* RTN_UNSPEC */
{
.error = 0,
.scope = RT_SCOPE_UNIVERSE,
}, /* RTN_UNICAST */
{
.error = 0,
.scope = RT_SCOPE_HOST,
}, /* RTN_LOCAL */
{
.error = 0,
.scope = RT_SCOPE_LINK,
}, /* RTN_BROADCAST */
{
.error = 0,
.scope = RT_SCOPE_LINK,
}, /* RTN_ANYCAST */
{
.error = 0,
.scope = RT_SCOPE_UNIVERSE,
}, /* RTN_MULTICAST */
{
.error = -EINVAL,
.scope = RT_SCOPE_UNIVERSE,
}, /* RTN_BLACKHOLE */
{
.error = -EHOSTUNREACH,
.scope = RT_SCOPE_UNIVERSE,
}, /* RTN_UNREACHABLE */
{
.error = -EACCES,
.scope = RT_SCOPE_UNIVERSE,
}, /* RTN_PROHIBIT */
{
.error = -EAGAIN,
.scope = RT_SCOPE_UNIVERSE,
}, /* RTN_THROW */
{
.error = -EINVAL,
.scope = RT_SCOPE_NOWHERE,
}, /* RTN_NAT */
{
.error = -EINVAL,
.scope = RT_SCOPE_NOWHERE,
}, /* RTN_XRESOLVE */
};
/* Release a nexthop info record */
void free_fib_info(struct fib_info *fi)
{
if (fi->fib_dead == 0) {
printk("Freeing alive fib_info %p\n", fi);
return;
}
change_nexthops(fi) {
if (nh->nh_dev)
dev_put(nh->nh_dev);
nh->nh_dev = NULL;
} endfor_nexthops(fi);
fib_info_cnt--;
kfree(fi);
}
void fib_release_info(struct fib_info *fi)
{
write_lock(&fib_info_lock);
if (fi && --fi->fib_treeref == 0) {
hlist_del(&fi->fib_hash);
if (fi->fib_prefsrc)
hlist_del(&fi->fib_lhash);
change_nexthops(fi) {
if (!nh->nh_dev)
continue;
hlist_del(&nh->nh_hash);
} endfor_nexthops(fi)
fi->fib_dead = 1;
fib_info_put(fi);
}
write_unlock(&fib_info_lock);
}
static __inline__ int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
{
const struct 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 ||
#ifdef CONFIG_IP_ROUTE_MULTIPATH
nh->nh_weight != onh->nh_weight ||
#endif
#ifdef CONFIG_NET_CLS_ROUTE
nh->nh_tclassid != onh->nh_tclassid ||
#endif
((nh->nh_flags^onh->nh_flags)&~RTNH_F_DEAD))
return -1;
onh++;
} endfor_nexthops(fi);
return 0;
}
static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
{
unsigned int mask = (fib_hash_size - 1);
unsigned int val = fi->fib_nhs;
val ^= fi->fib_protocol;
val ^= fi->fib_prefsrc;
val ^= fi->fib_priority;
return (val ^ (val >> 7) ^ (val >> 12)) & mask;
}
static struct fib_info *fib_find_info(const struct fib_info *nfi)
{
struct hlist_head *head;
struct hlist_node *node;
struct fib_info *fi;
unsigned int hash;
hash = fib_info_hashfn(nfi);
head = &fib_info_hash[hash];
hlist_for_each_entry(fi, node, head, fib_hash) {
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 || nh_comp(fi, nfi) == 0))
return fi;
}
return NULL;
}
static inline unsigned int fib_devindex_hashfn(unsigned int val)
{
unsigned int mask = DEVINDEX_HASHSIZE - 1;
return (val ^
(val >> DEVINDEX_HASHBITS) ^
(val >> (DEVINDEX_HASHBITS * 2))) & mask;
}
/* Check, that the gateway is already configured.
Used only by redirect accept routine.
*/
int ip_fib_check_default(u32 gw, struct net_device *dev)
{
struct hlist_head *head;
struct hlist_node *node;
struct fib_nh *nh;
unsigned int hash;
read_lock(&fib_info_lock);
hash = fib_devindex_hashfn(dev->ifindex);
head = &fib_info_devhash[hash];
hlist_for_each_entry(nh, node, head, nh_hash) {
if (nh->nh_dev == dev &&
nh->nh_gw == gw &&
!(nh->nh_flags&RTNH_F_DEAD)) {
read_unlock(&fib_info_lock);
return 0;
}
}
read_unlock(&fib_info_lock);
return -1;
}
void rtmsg_fib(int event, u32 key, struct fib_alias *fa,
int z, int tb_id,
struct nlmsghdr *n, struct netlink_skb_parms *req)
{
struct sk_buff *skb;
u32 pid = req ? req->pid : n->nlmsg_pid;
int size = NLMSG_SPACE(sizeof(struct rtmsg)+256);
skb = alloc_skb(size, GFP_KERNEL);
if (!skb)
return;
if (fib_dump_info(skb, pid, n->nlmsg_seq, event, tb_id,
fa->fa_type, fa->fa_scope, &key, z,
fa->fa_tos,
fa->fa_info, 0) < 0) {
kfree_skb(skb);
return;
}
NETLINK_CB(skb).dst_group = RTNLGRP_IPV4_ROUTE;
if (n->nlmsg_flags&NLM_F_ECHO)
atomic_inc(&skb->users);
netlink_broadcast(rtnl, skb, pid, RTNLGRP_IPV4_ROUTE, GFP_KERNEL);
if (n->nlmsg_flags&NLM_F_ECHO)
netlink_unicast(rtnl, skb, pid, MSG_DONTWAIT);
}
/* Return the first fib alias matching TOS with
* priority less than or equal to PRIO.
*/
struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio)
{
if (fah) {
struct fib_alias *fa;
list_for_each_entry(fa, fah, fa_list) {
if (fa->fa_tos > tos)
continue;
if (fa->fa_info->fib_priority >= prio ||
fa->fa_tos < tos)
return fa;
}
}
return NULL;
}
int fib_detect_death(struct fib_info *fi, int order,
struct fib_info **last_resort, int *last_idx, int *dflt)
{
struct neighbour *n;
int state = NUD_NONE;
n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
if (n) {
state = n->nud_state;
neigh_release(n);
}
if (state==NUD_REACHABLE)
return 0;
if ((state&NUD_VALID) && order != *dflt)
return 0;
if ((state&NUD_VALID) ||
(*last_idx<0 && order > *dflt)) {
*last_resort = fi;
*last_idx = order;
}
return 1;
}
#ifdef CONFIG_IP_ROUTE_MULTIPATH
static u32 fib_get_attr32(struct rtattr *attr, int attrlen, int type)
{
while (RTA_OK(attr,attrlen)) {
if (attr->rta_type == type)
return *(u32*)RTA_DATA(attr);
attr = RTA_NEXT(attr, attrlen);
}
return 0;
}
static int
fib_count_nexthops(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
fib_get_nhs(struct 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 = fib_get_attr32(RTNH_DATA(nhp), attrlen, RTA_GATEWAY);
#ifdef CONFIG_NET_CLS_ROUTE
nh->nh_tclassid = fib_get_attr32(RTNH_DATA(nhp), attrlen, RTA_FLOW);
#endif
}
nhp = RTNH_NEXT(nhp);
} endfor_nexthops(fi);
return 0;
}
#endif
int fib_nh_match(struct rtmsg *r, struct nlmsghdr *nlh, struct kern_rta *rta,
struct fib_info *fi)
{
#ifdef CONFIG_IP_ROUTE_MULTIPATH
struct rtnexthop *nhp;
int nhlen;
#endif
if (rta->rta_priority &&
*rta->rta_priority != fi->fib_priority)
return 1;
if (rta->rta_oif || rta->rta_gw) {
if ((!rta->rta_oif || *rta->rta_oif == fi->fib_nh->nh_oif) &&
(!rta->rta_gw || memcmp(rta->rta_gw, &fi->fib_nh->nh_gw, 4) == 0))
return 0;
return 1;
}
#ifdef CONFIG_IP_ROUTE_MULTIPATH
if (rta->rta_mp == NULL)
return 0;
nhp = RTA_DATA(rta->rta_mp);
nhlen = RTA_PAYLOAD(rta->rta_mp);
for_nexthops(fi) {
int attrlen = nhlen - sizeof(struct rtnexthop);
u32 gw;
if (attrlen < 0 || (nhlen -= nhp->rtnh_len) < 0)
return -EINVAL;
if (nhp->rtnh_ifindex && nhp->rtnh_ifindex != nh->nh_oif)
return 1;
if (attrlen) {
gw = fib_get_attr32(RTNH_DATA(nhp), attrlen, RTA_GATEWAY);
if (gw && gw != nh->nh_gw)
return 1;
#ifdef CONFIG_NET_CLS_ROUTE
gw = fib_get_attr32(RTNH_DATA(nhp), attrlen, RTA_FLOW);
if (gw && gw != nh->nh_tclassid)
return 1;
#endif
}
nhp = RTNH_NEXT(nhp);
} endfor_nexthops(fi);
#endif
return 0;
}
/*
Picture
-------
Semantics of nexthop is very messy by historical reasons.
We have to take into account, that:
a) gateway can be actually local interface address,
so that gatewayed route is direct.
b) gateway must be on-link address, possibly
described not by an ifaddr, but also by a direct route.
c) If both gateway and interface are specified, they should not
contradict.
d) If we use tunnel routes, gateway could be not on-link.
Attempt to reconcile all of these (alas, self-contradictory) conditions
results in pretty ugly and hairy code with obscure logic.
I chose to generalized it instead, so that the size
of code does not increase practically, but it becomes
much more general.
Every prefix is assigned a "scope" value: "host" is local address,
"link" is direct route,
[ ... "site" ... "interior" ... ]
and "universe" is true gateway route with global meaning.
Every prefix refers to a set of "nexthop"s (gw, oif),
where gw must have narrower scope. This recursion stops
when gw has LOCAL scope or if "nexthop" is declared ONLINK,
which means that gw is forced to be on link.
Code is still hairy, but now it is apparently logically
consistent and very flexible. F.e. as by-product it allows
to co-exists in peace independent exterior and interior
routing processes.
Normally it looks as following.
{universe prefix} -> (gw, oif) [scope link]
|
|-> {link prefix} -> (gw, oif) [scope local]
|
|-> {local prefix} (terminal node)
*/
static int fib_check_nh(const struct rtmsg *r, struct fib_info *fi, struct fib_nh *nh)
{
int err;
if (nh->nh_gw) {
struct fib_result res;
#ifdef CONFIG_IP_ROUTE_PERVASIVE
if (nh->nh_flags&RTNH_F_PERVASIVE)
return 0;
#endif
if (nh->nh_flags&RTNH_F_ONLINK) {
struct net_device *dev;
if (r->rtm_scope >= RT_SCOPE_LINK)
return -EINVAL;
if (inet_addr_type(nh->nh_gw) != RTN_UNICAST)
return -EINVAL;
if ((dev = __dev_get_by_index(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;
}
{
struct flowi fl = { .nl_u = { .ip4_u =
{ .daddr = nh->nh_gw,
.scope = r->rtm_scope + 1 } },
.oif = nh->nh_oif };
/* It is not necessary, but requires a bit of thinking */
if (fl.fl4_scope < RT_SCOPE_LINK)
fl.fl4_scope = RT_SCOPE_LINK;
if ((err = fib_lookup(&fl, &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 = FIB_RES_OIF(res);
if ((nh->nh_dev = FIB_RES_DEV(res)) == NULL)
goto out;
dev_hold(nh->nh_dev);
err = -ENETDOWN;
if (!(nh->nh_dev->flags & IFF_UP))
goto out;
err = 0;
out:
fib_res_put(&res);
return err;
} else {
struct in_device *in_dev;
if (nh->nh_flags&(RTNH_F_PERVASIVE|RTNH_F_ONLINK))
return -EINVAL;
in_dev = inetdev_by_index(nh->nh_oif);
if (in_dev == NULL)
return -ENODEV;
if (!(in_dev->dev->flags&IFF_UP)) {
in_dev_put(in_dev);
return -ENETDOWN;
}
nh->nh_dev = in_dev->dev;
dev_hold(nh->nh_dev);
nh->nh_scope = RT_SCOPE_HOST;
in_dev_put(in_dev);
}
return 0;
}
static inline unsigned int fib_laddr_hashfn(u32 val)
{
unsigned int mask = (fib_hash_size - 1);
return (val ^ (val >> 7) ^ (val >> 14)) & mask;
}
static struct hlist_head *fib_hash_alloc(int bytes)
{
if (bytes <= PAGE_SIZE)
return kmalloc(bytes, GFP_KERNEL);
else
return (struct hlist_head *)
__get_free_pages(GFP_KERNEL, get_order(bytes));
}
static void fib_hash_free(struct hlist_head *hash, int bytes)
{
if (!hash)
return;
if (bytes <= PAGE_SIZE)
kfree(hash);
else
free_pages((unsigned long) hash, get_order(bytes));
}
static void fib_hash_move(struct hlist_head *new_info_hash,
struct hlist_head *new_laddrhash,
unsigned int new_size)
{
struct hlist_head *old_info_hash, *old_laddrhash;
unsigned int old_size = fib_hash_size;
unsigned int i, bytes;
write_lock(&fib_info_lock);
old_info_hash = fib_info_hash;
old_laddrhash = fib_info_laddrhash;
fib_hash_size = new_size;
for (i = 0; i < old_size; i++) {
struct hlist_head *head = &fib_info_hash[i];
struct hlist_node *node, *n;
struct fib_info *fi;
hlist_for_each_entry_safe(fi, node, n, head, fib_hash) {
struct hlist_head *dest;
unsigned int new_hash;
hlist_del(&fi->fib_hash);
new_hash = fib_info_hashfn(fi);
dest = &new_info_hash[new_hash];
hlist_add_head(&fi->fib_hash, dest);
}
}
fib_info_hash = new_info_hash;
for (i = 0; i < old_size; i++) {
struct hlist_head *lhead = &fib_info_laddrhash[i];
struct hlist_node *node, *n;
struct fib_info *fi;
hlist_for_each_entry_safe(fi, node, n, lhead, fib_lhash) {
struct hlist_head *ldest;
unsigned int new_hash;
hlist_del(&fi->fib_lhash);
new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
ldest = &new_laddrhash[new_hash];
hlist_add_head(&fi->fib_lhash, ldest);
}
}
fib_info_laddrhash = new_laddrhash;
write_unlock(&fib_info_lock);
bytes = old_size * sizeof(struct hlist_head *);
fib_hash_free(old_info_hash, bytes);
fib_hash_free(old_laddrhash, bytes);
}
struct fib_info *
fib_create_info(const struct rtmsg *r, struct kern_rta *rta,
const struct nlmsghdr *nlh, int *errp)
{
int err;
struct fib_info *fi = NULL;
struct fib_info *ofi;
#ifdef CONFIG_IP_ROUTE_MULTIPATH
int nhs = 1;
#else
const int nhs = 1;
#endif
#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
u32 mp_alg = IP_MP_ALG_NONE;
#endif
/* Fast check to catch the most weird cases */
if (fib_props[r->rtm_type].scope > r->rtm_scope)
goto err_inval;
#ifdef CONFIG_IP_ROUTE_MULTIPATH
if (rta->rta_mp) {
nhs = fib_count_nexthops(rta->rta_mp);
if (nhs == 0)
goto err_inval;
}
#endif
#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
if (rta->rta_mp_alg) {
mp_alg = *rta->rta_mp_alg;
if (mp_alg < IP_MP_ALG_NONE ||
mp_alg > IP_MP_ALG_MAX)
goto err_inval;
}
#endif
err = -ENOBUFS;
if (fib_info_cnt >= fib_hash_size) {
unsigned int new_size = fib_hash_size << 1;
struct hlist_head *new_info_hash;
struct hlist_head *new_laddrhash;
unsigned int bytes;
if (!new_size)
new_size = 1;
bytes = new_size * sizeof(struct hlist_head *);
new_info_hash = fib_hash_alloc(bytes);
new_laddrhash = fib_hash_alloc(bytes);
if (!new_info_hash || !new_laddrhash) {
fib_hash_free(new_info_hash, bytes);
fib_hash_free(new_laddrhash, bytes);
} else {
memset(new_info_hash, 0, bytes);
memset(new_laddrhash, 0, bytes);
fib_hash_move(new_info_hash, new_laddrhash, new_size);
}
if (!fib_hash_size)
goto failure;
}
fi = kmalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
if (fi == NULL)
goto failure;
fib_info_cnt++;
memset(fi, 0, sizeof(*fi)+nhs*sizeof(struct fib_nh));
fi->fib_protocol = r->rtm_protocol;
fi->fib_nhs = nhs;
change_nexthops(fi) {
nh->nh_parent = fi;
} endfor_nexthops(fi)
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 flavor = attr->rta_type;
if (flavor) {
if (flavor > RTAX_MAX)
goto err_inval;
fi->fib_metrics[flavor-1] = *(unsigned*)RTA_DATA(attr);
}
attr = RTA_NEXT(attr, attrlen);
}
}
if (rta->rta_prefsrc)
memcpy(&fi->fib_prefsrc, rta->rta_prefsrc, 4);
if (rta->rta_mp) {
#ifdef CONFIG_IP_ROUTE_MULTIPATH
if ((err = 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, 4))
goto err_inval;
#ifdef CONFIG_NET_CLS_ROUTE
if (rta->rta_flow && memcmp(&fi->fib_nh->nh_tclassid, rta->rta_flow, 4))
goto err_inval;
#endif
#else
goto err_inval;
#endif
} else {
struct 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, 4);
#ifdef CONFIG_NET_CLS_ROUTE
if (rta->rta_flow)
memcpy(&nh->nh_tclassid, rta->rta_flow, 4);
#endif
nh->nh_flags = r->rtm_flags;
#ifdef CONFIG_IP_ROUTE_MULTIPATH
nh->nh_weight = 1;
#endif
}
#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
fi->fib_mp_alg = mp_alg;
#endif
if (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 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(fi->fib_nh->nh_oif);
err = -ENODEV;
if (nh->nh_dev == NULL)
goto failure;
} else {
change_nexthops(fi) {
if ((err = 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, 4))
if (inet_addr_type(fi->fib_prefsrc) != RTN_LOCAL)
goto err_inval;
}
link_it:
if ((ofi = fib_find_info(fi)) != NULL) {
fi->fib_dead = 1;
free_fib_info(fi);
ofi->fib_treeref++;
return ofi;
}
fi->fib_treeref++;
atomic_inc(&fi->fib_clntref);
write_lock(&fib_info_lock);
hlist_add_head(&fi->fib_hash,
&fib_info_hash[fib_info_hashfn(fi)]);
if (fi->fib_prefsrc) {
struct hlist_head *head;
head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
hlist_add_head(&fi->fib_lhash, head);
}
change_nexthops(fi) {
struct hlist_head *head;
unsigned int hash;
if (!nh->nh_dev)
continue;
hash = fib_devindex_hashfn(nh->nh_dev->ifindex);
head = &fib_info_devhash[hash];
hlist_add_head(&nh->nh_hash, head);
} endfor_nexthops(fi)
write_unlock(&fib_info_lock);
return fi;
err_inval:
err = -EINVAL;
failure:
*errp = err;
if (fi) {
fi->fib_dead = 1;
free_fib_info(fi);
}
return NULL;
}
/* Note! fib_semantic_match intentionally uses RCU list functions. */
int fib_semantic_match(struct list_head *head, const struct flowi *flp,
struct fib_result *res, __u32 zone, __u32 mask,
int prefixlen)
{
struct fib_alias *fa;
int nh_sel = 0;
list_for_each_entry_rcu(fa, head, fa_list) {
int err;
if (fa->fa_tos &&
fa->fa_tos != flp->fl4_tos)
continue;
if (fa->fa_scope < flp->fl4_scope)
continue;
fa->fa_state |= FA_S_ACCESSED;
err = fib_props[fa->fa_type].error;
if (err == 0) {
struct fib_info *fi = fa->fa_info;
if (fi->fib_flags & RTNH_F_DEAD)
continue;
switch (fa->fa_type) {
case RTN_UNICAST:
case RTN_LOCAL:
case RTN_BROADCAST:
case RTN_ANYCAST:
case RTN_MULTICAST:
for_nexthops(fi) {
if (nh->nh_flags&RTNH_F_DEAD)
continue;
if (!flp->oif || flp->oif == nh->nh_oif)
break;
}
#ifdef CONFIG_IP_ROUTE_MULTIPATH
if (nhsel < fi->fib_nhs) {
nh_sel = nhsel;
goto out_fill_res;
}
#else
if (nhsel < 1) {
goto out_fill_res;
}
#endif
endfor_nexthops(fi);
continue;
default:
printk(KERN_DEBUG "impossible 102\n");
return -EINVAL;
};
}
return err;
}
return 1;
out_fill_res:
res->prefixlen = prefixlen;
res->nh_sel = nh_sel;
res->type = fa->fa_type;
res->scope = fa->fa_scope;
res->fi = fa->fa_info;
#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
res->netmask = mask;
res->network = zone &
(0xFFFFFFFF >> (32 - prefixlen));
#endif
atomic_inc(&res->fi->fib_clntref);
return 0;
}
/* Find appropriate source address to this destination */
u32 __fib_res_prefsrc(struct fib_result *res)
{
return inet_select_addr(FIB_RES_DEV(*res), FIB_RES_GW(*res), res->scope);
}
int
fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
u8 tb_id, u8 type, u8 scope, void *dst, int dst_len, u8 tos,
struct fib_info *fi, unsigned int flags)
{
struct rtmsg *rtm;
struct nlmsghdr *nlh;
unsigned char *b = skb->tail;
nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*rtm), flags);
rtm = NLMSG_DATA(nlh);
rtm->rtm_family = AF_INET;
rtm->rtm_dst_len = dst_len;
rtm->rtm_src_len = 0;
rtm->rtm_tos = tos;
rtm->rtm_table = tb_id;
rtm->rtm_type = type;
rtm->rtm_flags = fi->fib_flags;
rtm->rtm_scope = scope;
if (rtm->rtm_dst_len)
RTA_PUT(skb, RTA_DST, 4, dst);
rtm->rtm_protocol = fi->fib_protocol;
if (fi->fib_priority)
RTA_PUT(skb, RTA_PRIORITY, 4, &fi->fib_priority);
#ifdef CONFIG_NET_CLS_ROUTE
if (fi->fib_nh[0].nh_tclassid)
RTA_PUT(skb, RTA_FLOW, 4, &fi->fib_nh[0].nh_tclassid);
#endif
if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
goto rtattr_failure;
if (fi->fib_prefsrc)
RTA_PUT(skb, RTA_PREFSRC, 4, &fi->fib_prefsrc);
if (fi->fib_nhs == 1) {
if (fi->fib_nh->nh_gw)
RTA_PUT(skb, RTA_GATEWAY, 4, &fi->fib_nh->nh_gw);
if (fi->fib_nh->nh_oif)
RTA_PUT(skb, RTA_OIF, sizeof(int), &fi->fib_nh->nh_oif);
}
#ifdef CONFIG_IP_ROUTE_MULTIPATH
if (fi->fib_nhs > 1) {
struct rtnexthop *nhp;
struct rtattr *mp_head;
if (skb_tailroom(skb) <= RTA_SPACE(0))
goto rtattr_failure;
mp_head = (struct rtattr*)skb_put(skb, RTA_SPACE(0));
for_nexthops(fi) {
if (skb_tailroom(skb) < RTA_ALIGN(RTA_ALIGN(sizeof(*nhp)) + 4))
goto rtattr_failure;
nhp = (struct rtnexthop*)skb_put(skb, RTA_ALIGN(sizeof(*nhp)));
nhp->rtnh_flags = nh->nh_flags & 0xFF;
nhp->rtnh_hops = nh->nh_weight-1;
nhp->rtnh_ifindex = nh->nh_oif;
if (nh->nh_gw)
RTA_PUT(skb, RTA_GATEWAY, 4, &nh->nh_gw);
nhp->rtnh_len = skb->tail - (unsigned char*)nhp;
} endfor_nexthops(fi);
mp_head->rta_type = RTA_MULTIPATH;
mp_head->rta_len = skb->tail - (u8*)mp_head;
}
#endif
nlh->nlmsg_len = skb->tail - b;
return skb->len;
nlmsg_failure:
rtattr_failure:
skb_trim(skb, b - skb->data);
return -1;
}
#ifndef CONFIG_IP_NOSIOCRT
int
fib_convert_rtentry(int cmd, struct nlmsghdr *nl, struct rtmsg *rtm,
struct kern_rta *rta, struct rtentry *r)
{
int plen;
u32 *ptr;
memset(rtm, 0, sizeof(*rtm));
memset(rta, 0, sizeof(*rta));
if (r->rt_dst.sa_family != AF_INET)
return -EAFNOSUPPORT;
/* Check mask for validity:
a) it must be contiguous.
b) destination must have all host bits clear.
c) if application forgot to set correct family (AF_INET),
reject request unless it is absolutely clear i.e.
both family and mask are zero.
*/
plen = 32;
ptr = &((struct sockaddr_in*)&r->rt_dst)->sin_addr.s_addr;
if (!(r->rt_flags&RTF_HOST)) {
u32 mask = ((struct sockaddr_in*)&r->rt_genmask)->sin_addr.s_addr;
if (r->rt_genmask.sa_family != AF_INET) {
if (mask || r->rt_genmask.sa_family)
return -EAFNOSUPPORT;
}
if (bad_mask(mask, *ptr))
return -EINVAL;
plen = inet_mask_len(mask);
}
nl->nlmsg_flags = NLM_F_REQUEST;
nl->nlmsg_pid = current->pid;
nl->nlmsg_seq = 0;
nl->nlmsg_len = NLMSG_LENGTH(sizeof(*rtm));
if (cmd == SIOCDELRT) {
nl->nlmsg_type = RTM_DELROUTE;
nl->nlmsg_flags = 0;
} else {
nl->nlmsg_type = RTM_NEWROUTE;
nl->nlmsg_flags = NLM_F_REQUEST|NLM_F_CREATE;
rtm->rtm_protocol = RTPROT_BOOT;
}
rtm->rtm_dst_len = plen;
rta->rta_dst = ptr;
if (r->rt_metric) {
*(u32*)&r->rt_pad3 = r->rt_metric - 1;
rta->rta_priority = (u32*)&r->rt_pad3;
}
if (r->rt_flags&RTF_REJECT) {
rtm->rtm_scope = RT_SCOPE_HOST;
rtm->rtm_type = RTN_UNREACHABLE;
return 0;
}
rtm->rtm_scope = RT_SCOPE_NOWHERE;
rtm->rtm_type = RTN_UNICAST;
if (r->rt_dev) {
char *colon;
struct net_device *dev;
char devname[IFNAMSIZ];
if (copy_from_user(devname, r->rt_dev, IFNAMSIZ-1))
return -EFAULT;
devname[IFNAMSIZ-1] = 0;
colon = strchr(devname, ':');
if (colon)
*colon = 0;
dev = __dev_get_by_name(devname);
if (!dev)
return -ENODEV;
rta->rta_oif = &dev->ifindex;
if (colon) {
struct in_ifaddr *ifa;
struct in_device *in_dev = __in_dev_get_rtnl(dev);
if (!in_dev)
return -ENODEV;
*colon = ':';
for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next)
if (strcmp(ifa->ifa_label, devname) == 0)
break;
if (ifa == NULL)
return -ENODEV;
rta->rta_prefsrc = &ifa->ifa_local;
}
}
ptr = &((struct sockaddr_in*)&r->rt_gateway)->sin_addr.s_addr;
if (r->rt_gateway.sa_family == AF_INET && *ptr) {
rta->rta_gw = ptr;
if (r->rt_flags&RTF_GATEWAY && inet_addr_type(*ptr) == RTN_UNICAST)
rtm->rtm_scope = RT_SCOPE_UNIVERSE;
}
if (cmd == SIOCDELRT)
return 0;
if (r->rt_flags&RTF_GATEWAY && rta->rta_gw == NULL)
return -EINVAL;
if (rtm->rtm_scope == RT_SCOPE_NOWHERE)
rtm->rtm_scope = RT_SCOPE_LINK;
if (r->rt_flags&(RTF_MTU|RTF_WINDOW|RTF_IRTT)) {
struct rtattr *rec;
struct rtattr *mx = kmalloc(RTA_LENGTH(3*RTA_LENGTH(4)), GFP_KERNEL);
if (mx == NULL)
return -ENOMEM;
rta->rta_mx = mx;
mx->rta_type = RTA_METRICS;
mx->rta_len = RTA_LENGTH(0);
if (r->rt_flags&RTF_MTU) {
rec = (void*)((char*)mx + RTA_ALIGN(mx->rta_len));
rec->rta_type = RTAX_ADVMSS;
rec->rta_len = RTA_LENGTH(4);
mx->rta_len += RTA_LENGTH(4);
*(u32*)RTA_DATA(rec) = r->rt_mtu - 40;
}
if (r->rt_flags&RTF_WINDOW) {
rec = (void*)((char*)mx + RTA_ALIGN(mx->rta_len));
rec->rta_type = RTAX_WINDOW;
rec->rta_len = RTA_LENGTH(4);
mx->rta_len += RTA_LENGTH(4);
*(u32*)RTA_DATA(rec) = r->rt_window;
}
if (r->rt_flags&RTF_IRTT) {
rec = (void*)((char*)mx + RTA_ALIGN(mx->rta_len));
rec->rta_type = RTAX_RTT;
rec->rta_len = RTA_LENGTH(4);
mx->rta_len += RTA_LENGTH(4);
*(u32*)RTA_DATA(rec) = r->rt_irtt<<3;
}
}
return 0;
}
#endif
/*
Update FIB if:
- local address disappeared -> we must delete all the entries
referring to it.
- device went down -> we must shutdown all nexthops going via it.
*/
int fib_sync_down(u32 local, struct net_device *dev, int force)
{
int ret = 0;
int scope = RT_SCOPE_NOWHERE;
if (force)
scope = -1;
if (local && fib_info_laddrhash) {
unsigned int hash = fib_laddr_hashfn(local);
struct hlist_head *head = &fib_info_laddrhash[hash];
struct hlist_node *node;
struct fib_info *fi;
hlist_for_each_entry(fi, node, head, fib_lhash) {
if (fi->fib_prefsrc == local) {
fi->fib_flags |= RTNH_F_DEAD;
ret++;
}
}
}
if (dev) {
struct fib_info *prev_fi = NULL;
unsigned int hash = fib_devindex_hashfn(dev->ifindex);
struct hlist_head *head = &fib_info_devhash[hash];
struct hlist_node *node;
struct fib_nh *nh;
hlist_for_each_entry(nh, node, head, nh_hash) {
struct fib_info *fi = nh->nh_parent;
int dead;
BUG_ON(!fi->fib_nhs);
if (nh->nh_dev != dev || fi == prev_fi)
continue;
prev_fi = fi;
dead = 0;
change_nexthops(fi) {
if (nh->nh_flags&RTNH_F_DEAD)
dead++;
else if (nh->nh_dev == dev &&
nh->nh_scope != scope) {
nh->nh_flags |= RTNH_F_DEAD;
#ifdef CONFIG_IP_ROUTE_MULTIPATH
spin_lock_bh(&fib_multipath_lock);
fi->fib_power -= nh->nh_power;
nh->nh_power = 0;
spin_unlock_bh(&fib_multipath_lock);
#endif
dead++;
}
#ifdef CONFIG_IP_ROUTE_MULTIPATH
if (force > 1 && nh->nh_dev == dev) {
dead = fi->fib_nhs;
break;
}
#endif
} endfor_nexthops(fi)
if (dead == fi->fib_nhs) {
fi->fib_flags |= RTNH_F_DEAD;
ret++;
}
}
}
return ret;
}
#ifdef CONFIG_IP_ROUTE_MULTIPATH
/*
Dead device goes up. We wake up dead nexthops.
It takes sense only on multipath routes.
*/
int fib_sync_up(struct net_device *dev)
{
struct fib_info *prev_fi;
unsigned int hash;
struct hlist_head *head;
struct hlist_node *node;
struct fib_nh *nh;
int ret;
if (!(dev->flags&IFF_UP))
return 0;
prev_fi = NULL;
hash = fib_devindex_hashfn(dev->ifindex);
head = &fib_info_devhash[hash];
ret = 0;
hlist_for_each_entry(nh, node, head, nh_hash) {
struct fib_info *fi = nh->nh_parent;
int alive;
BUG_ON(!fi->fib_nhs);
if (nh->nh_dev != dev || fi == prev_fi)
continue;
prev_fi = fi;
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 || !__in_dev_get_rtnl(dev))
continue;
alive++;
spin_lock_bh(&fib_multipath_lock);
nh->nh_power = 0;
nh->nh_flags &= ~RTNH_F_DEAD;
spin_unlock_bh(&fib_multipath_lock);
} endfor_nexthops(fi)
if (alive > 0) {
fi->fib_flags &= ~RTNH_F_DEAD;
ret++;
}
}
return ret;
}
/*
The algorithm is suboptimal, but it provides really
fair weighted route distribution.
*/
void fib_select_multipath(const struct flowi *flp, struct fib_result *res)
{
struct fib_info *fi = res->fi;
int w;
spin_lock_bh(&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(&fib_multipath_lock);
/* Race condition: route has just become dead. */
res->nh_sel = 0;
return;
}
}
/* w should be random number [0..fi->fib_power-1],
it is pretty bad approximation.
*/
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(&fib_multipath_lock);
return;
}
}
} endfor_nexthops(fi);
/* Race condition: route has just become dead. */
res->nh_sel = 0;
spin_unlock_bh(&fib_multipath_lock);
}
#endif
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