iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

netfilter: ecache: use dedicated list for event redelivery

Browse Source 
This disentangles event redelivery and the percpu dying list.

Because entries are now stored on a dedicated list, all
entries are in NFCT_ECACHE_DESTROY_FAIL state and all entries
still have confirmed bit set -- the reference count is at least 1.

The 'struct net' back-pointer can be removed as well.

The pcpu dying list will be removed eventually, it has no functionality.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2022-04-11 13:01:16 +02:00 committed by Pablo Neira Ayuso
parent a997157e42
commit 2ed3bf188b
4 changed files with 81 additions and 72 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/net/netfilter/nf_conntrack.h
View File

@ -45,7 +45,8 @@ union nf_conntrack_expect_proto {
struct nf_conntrack_net_ecache {
struct delayed_work dwork;
struct netns_ct *ct_net;
spinlock_t dying_lock;
struct hlist_nulls_head dying_list;
};
struct nf_conntrack_net {

2
include/net/netfilter/nf_conntrack_ecache.h
View File

@ -14,7 +14,6 @@
#include <net/netfilter/nf_conntrack_extend.h>
enum nf_ct_ecache_state {
NFCT_ECACHE_UNKNOWN, /* destroy event not sent */
NFCT_ECACHE_DESTROY_FAIL, /* tried but failed to send destroy event */
NFCT_ECACHE_DESTROY_SENT, /* sent destroy event after failure */
};
@ -23,7 +22,6 @@ struct nf_conntrack_ecache {
unsigned long cache; /* bitops want long */
u16 ctmask; /* bitmask of ct events to be delivered */
u16 expmask; /* bitmask of expect events to be delivered */
enum nf_ct_ecache_state state:8;/* ecache state */
u32 missed; /* missed events */
u32 portid; /* netlink portid of destroyer */
};

33
net/netfilter/nf_conntrack_core.c
View File

@ -660,15 +660,12 @@ void nf_ct_destroy(struct nf_conntrack *nfct)
}
EXPORT_SYMBOL(nf_ct_destroy);
static void nf_ct_delete_from_lists(struct nf_conn *ct)
static void __nf_ct_delete_from_lists(struct nf_conn *ct)
{
struct net *net = nf_ct_net(ct);
unsigned int hash, reply_hash;
unsigned int sequence;
nf_ct_helper_destroy(ct);
local_bh_disable();
do {
sequence = read_seqcount_begin(&nf_conntrack_generation);
hash = hash_conntrack(net,
@ -681,12 +678,33 @@ static void nf_ct_delete_from_lists(struct nf_conn *ct)
clean_from_lists(ct);
nf_conntrack_double_unlock(hash, reply_hash);
}
static void nf_ct_delete_from_lists(struct nf_conn *ct)
{
nf_ct_helper_destroy(ct);
local_bh_disable();
__nf_ct_delete_from_lists(ct);
nf_ct_add_to_dying_list(ct);
local_bh_enable();
}
static void nf_ct_add_to_ecache_list(struct nf_conn *ct)
{
#ifdef CONFIG_NF_CONNTRACK_EVENTS
struct nf_conntrack_net *cnet = nf_ct_pernet(nf_ct_net(ct));
spin_lock(&cnet->ecache.dying_lock);
hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
&cnet->ecache.dying_list);
spin_unlock(&cnet->ecache.dying_lock);
#else
nf_ct_add_to_dying_list(ct);
#endif
}
bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report)
{
struct nf_conn_tstamp *tstamp;
@ -709,7 +727,12 @@ bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report)
/* destroy event was not delivered. nf_ct_put will
* be done by event cache worker on redelivery.
*/
nf_ct_delete_from_lists(ct);
nf_ct_helper_destroy(ct);
local_bh_disable();
__nf_ct_delete_from_lists(ct);
nf_ct_add_to_ecache_list(ct);
local_bh_enable();
nf_conntrack_ecache_work(nf_ct_net(ct), NFCT_ECACHE_DESTROY_FAIL);
return false;
}

115
net/netfilter/nf_conntrack_ecache.c
View File

@ -16,7 +16,6 @@
#include <linux/vmalloc.h>
#include <linux/stddef.h>
#include <linux/err.h>
#include <linux/percpu.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/slab.h>
@ -29,8 +28,9 @@
static DEFINE_MUTEX(nf_ct_ecache_mutex);
#define ECACHE_RETRY_WAIT (HZ/10)
#define ECACHE_STACK_ALLOC (256 / sizeof(void *))
#define DYING_NULLS_VAL ((1 << 30) + 1)
#define ECACHE_MAX_JIFFIES msecs_to_jiffies(10)
#define ECACHE_RETRY_JIFFIES msecs_to_jiffies(10)
enum retry_state {
STATE_CONGESTED,
@ -38,58 +38,58 @@ enum retry_state {
STATE_DONE,
};
static enum retry_state ecache_work_evict_list(struct ct_pcpu *pcpu)
static enum retry_state ecache_work_evict_list(struct nf_conntrack_net *cnet)
{
struct nf_conn *refs[ECACHE_STACK_ALLOC];
unsigned long stop = jiffies + ECACHE_MAX_JIFFIES;
struct hlist_nulls_head evicted_list;
enum retry_state ret = STATE_DONE;
struct nf_conntrack_tuple_hash *h;
struct hlist_nulls_node *n;
unsigned int evicted = 0;
unsigned int sent;
spin_lock(&pcpu->lock);
INIT_HLIST_NULLS_HEAD(&evicted_list, DYING_NULLS_VAL);
hlist_nulls_for_each_entry(h, n, &pcpu->dying, hnnode) {
next:
sent = 0;
spin_lock_bh(&cnet->ecache.dying_lock);
hlist_nulls_for_each_entry_safe(h, n, &cnet->ecache.dying_list, hnnode) {
struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
struct nf_conntrack_ecache *e;
if (!nf_ct_is_confirmed(ct))
continue;
/* This ecache access is safe because the ct is on the
* pcpu dying list and we hold the spinlock -- the entry
* cannot be free'd until after the lock is released.
*
* This is true even if ct has a refcount of 0: the
* cpu that is about to free the entry must remove it
* from the dying list and needs the lock to do so.
*/
e = nf_ct_ecache_find(ct);
if (!e || e->state != NFCT_ECACHE_DESTROY_FAIL)
continue;
/* ct is in NFCT_ECACHE_DESTROY_FAIL state, this means
* the worker owns this entry: the ct will remain valid
* until the worker puts its ct reference.
/* The worker owns all entries, ct remains valid until nf_ct_put
* in the loop below.
*/
if (nf_conntrack_event(IPCT_DESTROY, ct)) {
ret = STATE_CONGESTED;
break;
}
e->state = NFCT_ECACHE_DESTROY_SENT;
refs[evicted] = ct;
hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode, &evicted_list);
if (++evicted >= ARRAY_SIZE(refs)) {
if (time_after(stop, jiffies)) {
ret = STATE_RESTART;
break;
}
if (sent++ > 16) {
spin_unlock_bh(&cnet->ecache.dying_lock);
cond_resched();
goto next;
}
}
spin_unlock(&pcpu->lock);
spin_unlock_bh(&cnet->ecache.dying_lock);
/* can't _put while holding lock */
while (evicted)
nf_ct_put(refs[--evicted]);
hlist_nulls_for_each_entry_safe(h, n, &evicted_list, hnnode) {
struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
hlist_nulls_add_fake(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
nf_ct_put(ct);
cond_resched();
}
return ret;
}
@ -97,35 +97,20 @@ static enum retry_state ecache_work_evict_list(struct ct_pcpu *pcpu)
static void ecache_work(struct work_struct *work)
{
struct nf_conntrack_net *cnet = container_of(work, struct nf_conntrack_net, ecache.dwork.work);
struct netns_ct *ctnet = cnet->ecache.ct_net;
int cpu, delay = -1;
struct ct_pcpu *pcpu;
int ret, delay = -1;
local_bh_disable();
for_each_possible_cpu(cpu) {
enum retry_state ret;
pcpu = per_cpu_ptr(ctnet->pcpu_lists, cpu);
ret = ecache_work_evict_list(pcpu);
switch (ret) {
case STATE_CONGESTED:
delay = ECACHE_RETRY_WAIT;
goto out;
case STATE_RESTART:
delay = 0;
break;
case STATE_DONE:
break;
}
ret = ecache_work_evict_list(cnet);
switch (ret) {
case STATE_CONGESTED:
delay = ECACHE_RETRY_JIFFIES;
break;
case STATE_RESTART:
delay = 0;
break;
case STATE_DONE:
break;
}
out:
local_bh_enable();
ctnet->ecache_dwork_pending = delay > 0;
if (delay >= 0)
schedule_delayed_work(&cnet->ecache.dwork, delay);
}
@ -199,7 +184,6 @@ int nf_conntrack_eventmask_report(unsigned int events, struct nf_conn *ct,
*/
if (e->portid == 0 && portid != 0)
e->portid = portid;
e->state = NFCT_ECACHE_DESTROY_FAIL;
}
return ret;
@ -297,8 +281,10 @@ void nf_conntrack_ecache_work(struct net *net, enum nf_ct_ecache_state state)
schedule_delayed_work(&cnet->ecache.dwork, HZ);
net->ct.ecache_dwork_pending = true;
} else if (state == NFCT_ECACHE_DESTROY_SENT) {
net->ct.ecache_dwork_pending = false;
mod_delayed_work(system_wq, &cnet->ecache.dwork, 0);
if (!hlist_nulls_empty(&cnet->ecache.dying_list))
mod_delayed_work(system_wq, &cnet->ecache.dwork, 0);
else
net->ct.ecache_dwork_pending = false;
}
}
@ -311,8 +297,9 @@ void nf_conntrack_ecache_pernet_init(struct net *net)
net->ct.sysctl_events = nf_ct_events;
cnet->ecache.ct_net = &net->ct;
INIT_DELAYED_WORK(&cnet->ecache.dwork, ecache_work);
INIT_HLIST_NULLS_HEAD(&cnet->ecache.dying_list, DYING_NULLS_VAL);
spin_lock_init(&cnet->ecache.dying_lock);
BUILD_BUG_ON(__IPCT_MAX >= 16); /* e->ctmask is u16 */
}