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flow: virtualize flow cache entry methods

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This allows to validate the cached object before returning it.
It also allows to destruct object properly, if the last reference
was held in flow cache. This is also a prepartion for caching
bundles in the flow cache.

In return for virtualizing the methods, we save on:
- not having to regenerate the whole flow cache on policy removal:
  each flow matching a killed policy gets refreshed as the getter
  function notices it smartly.
- we do not have to call flow_cache_flush from policy gc, since the
  flow cache now properly deletes the object if it had any references

Signed-off-by: Timo Teras <timo.teras@iki.fi>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Timo Teräs 2010-04-07 00:30:04 +00:00 committed by David S. Miller
parent 8020eb82d4
commit fe1a5f031e
4 changed files with 163 additions and 102 deletions
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23
include/net/flow.h
View file

@ -86,11 +86,26 @@ struct flowi {
struct net;
struct sock;
typedef int (*flow_resolve_t)(struct net *net, struct flowi *key, u16 family,
u8 dir, void **objp, atomic_t **obj_refp);
struct flow_cache_ops;
struct flow_cache_object {
const struct flow_cache_ops *ops;
};
struct flow_cache_ops {
struct flow_cache_object *(*get)(struct flow_cache_object *);
int (*check)(struct flow_cache_object *);
void (*delete)(struct flow_cache_object *);
};
typedef struct flow_cache_object *(*flow_resolve_t)(
struct net *net, struct flowi *key, u16 family,
u8 dir, struct flow_cache_object *oldobj, void *ctx);
extern struct flow_cache_object *flow_cache_lookup(
struct net *net, struct flowi *key, u16 family,
u8 dir, flow_resolve_t resolver, void *ctx);
extern void *flow_cache_lookup(struct net *net, struct flowi *key, u16 family,
u8 dir, flow_resolve_t resolver);
extern void flow_cache_flush(void);
extern atomic_t flow_cache_genid;

2
include/net/xfrm.h
View file

@ -19,6 +19,7 @@
#include <net/route.h>
#include <net/ipv6.h>
#include <net/ip6_fib.h>
#include <net/flow.h>
#include <linux/interrupt.h>
@ -481,6 +482,7 @@ struct xfrm_policy {
atomic_t refcnt;
struct timer_list timer;
struct flow_cache_object flo;
u32 priority;
u32 index;
struct xfrm_mark mark;

128
net/core/flow.c
View file

@ -26,17 +26,16 @@
#include <linux/security.h>
struct flow_cache_entry {
struct flow_cache_entry *next;
u16 family;
u8 dir;
u32 genid;
struct flowi key;
void *object;
atomic_t *object_ref;
struct flow_cache_entry *next;
u16 family;
u8 dir;
u32 genid;
struct flowi key;
struct flow_cache_object *object;
};
struct flow_cache_percpu {
struct flow_cache_entry ** hash_table;
struct flow_cache_entry **hash_table;
int hash_count;
u32 hash_rnd;
int hash_rnd_recalc;
@ -44,7 +43,7 @@ struct flow_cache_percpu {
};
struct flow_flush_info {
struct flow_cache * cache;
struct flow_cache *cache;
atomic_t cpuleft;
struct completion completion;
};
@ -52,7 +51,7 @@ struct flow_flush_info {
struct flow_cache {
u32 hash_shift;
unsigned long order;
struct flow_cache_percpu * percpu;
struct flow_cache_percpu *percpu;
struct notifier_block hotcpu_notifier;
int low_watermark;
int high_watermark;
@ -78,12 +77,21 @@ static void flow_cache_new_hashrnd(unsigned long arg)
add_timer(&fc->rnd_timer);
}
static int flow_entry_valid(struct flow_cache_entry *fle)
{
if (atomic_read(&flow_cache_genid) != fle->genid)
return 0;
if (fle->object && !fle->object->ops->check(fle->object))
return 0;
return 1;
}
static void flow_entry_kill(struct flow_cache *fc,
struct flow_cache_percpu *fcp,
struct flow_cache_entry *fle)
{
if (fle->object)
atomic_dec(fle->object_ref);
fle->object->ops->delete(fle->object);
kmem_cache_free(flow_cachep, fle);
fcp->hash_count--;
}
@ -96,16 +104,18 @@ static void __flow_cache_shrink(struct flow_cache *fc,
int i;
for (i = 0; i < flow_cache_hash_size(fc); i++) {
int k = 0;
int saved = 0;
flp = &fcp->hash_table[i];
while ((fle = *flp) != NULL && k < shrink_to) {
k++;
flp = &fle->next;
}
while ((fle = *flp) != NULL) {
*flp = fle->next;
flow_entry_kill(fc, fcp, fle);
if (saved < shrink_to &&
flow_entry_valid(fle)) {
saved++;
flp = &fle->next;
} else {
*flp = fle->next;
flow_entry_kill(fc, fcp, fle);
}
}
}
}
@ -166,18 +176,21 @@ static int flow_key_compare(struct flowi *key1, struct flowi *key2)
return 0;
}
void *flow_cache_lookup(struct net *net, struct flowi *key, u16 family, u8 dir,
flow_resolve_t resolver)
struct flow_cache_object *
flow_cache_lookup(struct net *net, struct flowi *key, u16 family, u8 dir,
flow_resolve_t resolver, void *ctx)
{
struct flow_cache *fc = &flow_cache_global;
struct flow_cache_percpu *fcp;
struct flow_cache_entry *fle, **head;
struct flow_cache_object *flo;
unsigned int hash;
local_bh_disable();
fcp = per_cpu_ptr(fc->percpu, smp_processor_id());
fle = NULL;
flo = NULL;
/* Packet really early in init? Making flow_cache_init a
* pre-smp initcall would solve this. --RR */
if (!fcp->hash_table)
@ -185,27 +198,17 @@ void *flow_cache_lookup(struct net *net, struct flowi *key, u16 family, u8 dir,
if (fcp->hash_rnd_recalc)
flow_new_hash_rnd(fc, fcp);
hash = flow_hash_code(fc, fcp, key);
hash = flow_hash_code(fc, fcp, key);
head = &fcp->hash_table[hash];
for (fle = *head; fle; fle = fle->next) {
if (fle->family == family &&
fle->dir == dir &&
flow_key_compare(key, &fle->key) == 0) {
if (fle->genid == atomic_read(&flow_cache_genid)) {
void *ret = fle->object;
if (ret)
atomic_inc(fle->object_ref);
local_bh_enable();
return ret;
}
flow_key_compare(key, &fle->key) == 0)
break;
}
}
if (!fle) {
if (unlikely(!fle)) {
if (fcp->hash_count > fc->high_watermark)
flow_cache_shrink(fc, fcp);
@ -219,33 +222,39 @@ void *flow_cache_lookup(struct net *net, struct flowi *key, u16 family, u8 dir,
fle->object = NULL;
fcp->hash_count++;
}
} else if (likely(fle->genid == atomic_read(&flow_cache_genid))) {
flo = fle->object;
if (!flo)
goto ret_object;
flo = flo->ops->get(flo);
if (flo)
goto ret_object;
} else if (fle->object) {
flo = fle->object;
flo->ops->delete(flo);
fle->object = NULL;
}
nocache:
{
int err;
void *obj;
atomic_t *obj_ref;
err = resolver(net, key, family, dir, &obj, &obj_ref);
if (fle && !err) {
fle->genid = atomic_read(&flow_cache_genid);
if (fle->object)
atomic_dec(fle->object_ref);
fle->object = obj;
fle->object_ref = obj_ref;
if (obj)
atomic_inc(fle->object_ref);
}
local_bh_enable();
if (err)
obj = ERR_PTR(err);
return obj;
flo = NULL;
if (fle) {
flo = fle->object;
fle->object = NULL;
}
flo = resolver(net, key, family, dir, flo, ctx);
if (fle) {
fle->genid = atomic_read(&flow_cache_genid);
if (!IS_ERR(flo))
fle->object = flo;
else
fle->genid--;
} else {
if (flo && !IS_ERR(flo))
flo->ops->delete(flo);
}
ret_object:
local_bh_enable();
return flo;
}
static void flow_cache_flush_tasklet(unsigned long data)
@ -261,13 +270,12 @@ static void flow_cache_flush_tasklet(unsigned long data)
fle = fcp->hash_table[i];
for (; fle; fle = fle->next) {
unsigned genid = atomic_read(&flow_cache_genid);
if (!fle->object || fle->genid == genid)
if (flow_entry_valid(fle))
continue;
if (fle->object)
fle->object->ops->delete(fle->object);
fle->object = NULL;
atomic_dec(fle->object_ref);
}
}

112
net/xfrm/xfrm_policy.c
View file

@ -216,6 +216,35 @@ static void xfrm_policy_timer(unsigned long data)
xfrm_pol_put(xp);
}
static struct flow_cache_object *xfrm_policy_flo_get(struct flow_cache_object *flo)
{
struct xfrm_policy *pol = container_of(flo, struct xfrm_policy, flo);
if (unlikely(pol->walk.dead))
flo = NULL;
else
xfrm_pol_hold(pol);
return flo;
}
static int xfrm_policy_flo_check(struct flow_cache_object *flo)
{
struct xfrm_policy *pol = container_of(flo, struct xfrm_policy, flo);
return !pol->walk.dead;
}
static void xfrm_policy_flo_delete(struct flow_cache_object *flo)
{
xfrm_pol_put(container_of(flo, struct xfrm_policy, flo));
}
static const struct flow_cache_ops xfrm_policy_fc_ops = {
.get = xfrm_policy_flo_get,
.check = xfrm_policy_flo_check,
.delete = xfrm_policy_flo_delete,
};
/* Allocate xfrm_policy. Not used here, it is supposed to be used by pfkeyv2
* SPD calls.
@ -236,6 +265,7 @@ struct xfrm_policy *xfrm_policy_alloc(struct net *net, gfp_t gfp)
atomic_set(&policy->refcnt, 1);
setup_timer(&policy->timer, xfrm_policy_timer,
(unsigned long)policy);
policy->flo.ops = &xfrm_policy_fc_ops;
}
return policy;
}
@ -269,9 +299,6 @@ static void xfrm_policy_gc_kill(struct xfrm_policy *policy)
if (del_timer(&policy->timer))
atomic_dec(&policy->refcnt);
if (atomic_read(&policy->refcnt) > 1)
flow_cache_flush();
xfrm_pol_put(policy);
}
@ -661,10 +688,8 @@ struct xfrm_policy *xfrm_policy_bysel_ctx(struct net *net, u32 mark, u8 type,
}
write_unlock_bh(&xfrm_policy_lock);
if (ret && delete) {
atomic_inc(&flow_cache_genid);
if (ret && delete)
xfrm_policy_kill(ret);
}
return ret;
}
EXPORT_SYMBOL(xfrm_policy_bysel_ctx);
@ -703,10 +728,8 @@ struct xfrm_policy *xfrm_policy_byid(struct net *net, u32 mark, u8 type,
}
write_unlock_bh(&xfrm_policy_lock);
if (ret && delete) {
atomic_inc(&flow_cache_genid);
if (ret && delete)
xfrm_policy_kill(ret);
}
return ret;
}
EXPORT_SYMBOL(xfrm_policy_byid);
@ -822,7 +845,6 @@ int xfrm_policy_flush(struct net *net, u8 type, struct xfrm_audit *audit_info)
}
if (!cnt)
err = -ESRCH;
atomic_inc(&flow_cache_genid);
out:
write_unlock_bh(&xfrm_policy_lock);
return err;
@ -976,32 +998,35 @@ static struct xfrm_policy *xfrm_policy_lookup_bytype(struct net *net, u8 type,
return ret;
}
static int xfrm_policy_lookup(struct net *net, struct flowi *fl, u16 family,
u8 dir, void **objp, atomic_t **obj_refp)
static struct flow_cache_object *
xfrm_policy_lookup(struct net *net, struct flowi *fl, u16 family,
u8 dir, struct flow_cache_object *old_obj, void *ctx)
{
struct xfrm_policy *pol;
int err = 0;
if (old_obj)
xfrm_pol_put(container_of(old_obj, struct xfrm_policy, flo));
#ifdef CONFIG_XFRM_SUB_POLICY
pol = xfrm_policy_lookup_bytype(net, XFRM_POLICY_TYPE_SUB, fl, family, dir);
if (IS_ERR(pol)) {
err = PTR_ERR(pol);
pol = NULL;
}
if (pol || err)
goto end;
if (IS_ERR(pol))
return ERR_CAST(pol);
if (pol)
goto found;
#endif
pol = xfrm_policy_lookup_bytype(net, XFRM_POLICY_TYPE_MAIN, fl, family, dir);
if (IS_ERR(pol)) {
err = PTR_ERR(pol);
pol = NULL;
}
#ifdef CONFIG_XFRM_SUB_POLICY
end:
#endif
if ((*objp = (void *) pol) != NULL)
*obj_refp = &pol->refcnt;
return err;
if (IS_ERR(pol))
return ERR_CAST(pol);
if (pol)
goto found;
return NULL;
found:
/* Resolver returns two references:
* one for cache and one for caller of flow_cache_lookup() */
xfrm_pol_hold(pol);
return &pol->flo;
}
static inline int policy_to_flow_dir(int dir)
@ -1091,8 +1116,6 @@ int xfrm_policy_delete(struct xfrm_policy *pol, int dir)
pol = __xfrm_policy_unlink(pol, dir);
write_unlock_bh(&xfrm_policy_lock);
if (pol) {
if (dir < XFRM_POLICY_MAX)
atomic_inc(&flow_cache_genid);
xfrm_policy_kill(pol);
return 0;
}
@ -1578,18 +1601,24 @@ int __xfrm_lookup(struct net *net, struct dst_entry **dst_p, struct flowi *fl,
}
if (!policy) {
struct flow_cache_object *flo;
/* To accelerate a bit... */
if ((dst_orig->flags & DST_NOXFRM) ||
!net->xfrm.policy_count[XFRM_POLICY_OUT])
goto nopol;
policy = flow_cache_lookup(net, fl, dst_orig->ops->family,
dir, xfrm_policy_lookup);
err = PTR_ERR(policy);
if (IS_ERR(policy)) {
flo = flow_cache_lookup(net, fl, dst_orig->ops->family,
dir, xfrm_policy_lookup, NULL);
err = PTR_ERR(flo);
if (IS_ERR(flo)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTPOLERROR);
goto dropdst;
}
if (flo)
policy = container_of(flo, struct xfrm_policy, flo);
else
policy = NULL;
}
if (!policy)
@ -1939,9 +1968,16 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
}
}
if (!pol)
pol = flow_cache_lookup(net, &fl, family, fl_dir,
xfrm_policy_lookup);
if (!pol) {
struct flow_cache_object *flo;
flo = flow_cache_lookup(net, &fl, family, fl_dir,
xfrm_policy_lookup, NULL);
if (IS_ERR_OR_NULL(flo))
pol = ERR_CAST(flo);
else
pol = container_of(flo, struct xfrm_policy, flo);
}
if (IS_ERR(pol)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINPOLERROR);