Commit 04c494e6 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

Revert "tcp/dccp: get rid of inet_twsk_purge()"

This reverts commits:

0dad4087 ("tcp/dccp: get rid of inet_twsk_purge()")
d507204d ("tcp/dccp: add tw->tw_bslot")

As Leonard pointed out, a newly allocated netns can happen
to reuse a freed 'struct net'.

While TCP TW timers were covered by my patches, other things were not:

1) Lookups in rx path (INET_MATCH() and INET6_MATCH()), as they look
  at 4-tuple plus the 'struct net' pointer.

2) /proc/net/tcp[6] and inet_diag, same reason.

3) hashinfo->bhash[], same reason.

Fixing all this seems risky, lets instead revert.

In the future, we might have a per netns tcp hash table, or
a per netns list of timewait sockets...

Fixes: 0dad4087 ("tcp/dccp: get rid of inet_twsk_purge()")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reported-by: default avatarLeonard Crestez <cdleonard@gmail.com>
Tested-by: default avatarLeonard Crestez <cdleonard@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9646ee44
......@@ -71,7 +71,6 @@ struct inet_timewait_sock {
tw_tos : 8;
u32 tw_txhash;
u32 tw_priority;
u32 tw_bslot; /* bind bucket slot */
struct timer_list tw_timer;
struct inet_bind_bucket *tw_tb;
};
......@@ -110,6 +109,8 @@ static inline void inet_twsk_reschedule(struct inet_timewait_sock *tw, int timeo
void inet_twsk_deschedule_put(struct inet_timewait_sock *tw);
void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family);
static inline
struct net *twsk_net(const struct inet_timewait_sock *twsk)
{
......
......@@ -1030,9 +1030,15 @@ static void __net_exit dccp_v4_exit_net(struct net *net)
inet_ctl_sock_destroy(pn->v4_ctl_sk);
}
static void __net_exit dccp_v4_exit_batch(struct list_head *net_exit_list)
{
inet_twsk_purge(&dccp_hashinfo, AF_INET);
}
static struct pernet_operations dccp_v4_ops = {
.init = dccp_v4_init_net,
.exit = dccp_v4_exit_net,
.exit_batch = dccp_v4_exit_batch,
.id = &dccp_v4_pernet_id,
.size = sizeof(struct dccp_v4_pernet),
};
......
......@@ -1115,9 +1115,15 @@ static void __net_exit dccp_v6_exit_net(struct net *net)
inet_ctl_sock_destroy(pn->v6_ctl_sk);
}
static void __net_exit dccp_v6_exit_batch(struct list_head *net_exit_list)
{
inet_twsk_purge(&dccp_hashinfo, AF_INET6);
}
static struct pernet_operations dccp_v6_ops = {
.init = dccp_v6_init_net,
.exit = dccp_v6_exit_net,
.exit_batch = dccp_v6_exit_batch,
.id = &dccp_v6_pernet_id,
.size = sizeof(struct dccp_v6_pernet),
};
......
......@@ -52,7 +52,8 @@ static void inet_twsk_kill(struct inet_timewait_sock *tw)
spin_unlock(lock);
/* Disassociate with bind bucket. */
bhead = &hashinfo->bhash[tw->tw_bslot];
bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), tw->tw_num,
hashinfo->bhash_size)];
spin_lock(&bhead->lock);
inet_twsk_bind_unhash(tw, hashinfo);
......@@ -111,12 +112,8 @@ void inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
Note, that any socket with inet->num != 0 MUST be bound in
binding cache, even if it is closed.
*/
/* Cache inet_bhashfn(), because 'struct net' might be no longer
* available later in inet_twsk_kill().
*/
tw->tw_bslot = inet_bhashfn(twsk_net(tw), inet->inet_num,
hashinfo->bhash_size);
bhead = &hashinfo->bhash[tw->tw_bslot];
bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), inet->inet_num,
hashinfo->bhash_size)];
spin_lock(&bhead->lock);
tw->tw_tb = icsk->icsk_bind_hash;
WARN_ON(!icsk->icsk_bind_hash);
......@@ -257,3 +254,50 @@ void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo, bool rearm)
}
}
EXPORT_SYMBOL_GPL(__inet_twsk_schedule);
void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family)
{
struct inet_timewait_sock *tw;
struct sock *sk;
struct hlist_nulls_node *node;
unsigned int slot;
for (slot = 0; slot <= hashinfo->ehash_mask; slot++) {
struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
restart_rcu:
cond_resched();
rcu_read_lock();
restart:
sk_nulls_for_each_rcu(sk, node, &head->chain) {
if (sk->sk_state != TCP_TIME_WAIT)
continue;
tw = inet_twsk(sk);
if ((tw->tw_family != family) ||
refcount_read(&twsk_net(tw)->ns.count))
continue;
if (unlikely(!refcount_inc_not_zero(&tw->tw_refcnt)))
continue;
if (unlikely((tw->tw_family != family) ||
refcount_read(&twsk_net(tw)->ns.count))) {
inet_twsk_put(tw);
goto restart;
}
rcu_read_unlock();
local_bh_disable();
inet_twsk_deschedule_put(tw);
local_bh_enable();
goto restart_rcu;
}
/* If the nulls value we got at the end of this lookup is
* not the expected one, we must restart lookup.
* We probably met an item that was moved to another chain.
*/
if (get_nulls_value(node) != slot)
goto restart;
rcu_read_unlock();
}
}
EXPORT_SYMBOL_GPL(inet_twsk_purge);
......@@ -3173,6 +3173,8 @@ static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
{
struct net *net;
inet_twsk_purge(&tcp_hashinfo, AF_INET);
list_for_each_entry(net, net_exit_list, exit_list)
tcp_fastopen_ctx_destroy(net);
}
......
......@@ -2207,9 +2207,15 @@ static void __net_exit tcpv6_net_exit(struct net *net)
inet_ctl_sock_destroy(net->ipv6.tcp_sk);
}
static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
{
inet_twsk_purge(&tcp_hashinfo, AF_INET6);
}
static struct pernet_operations tcpv6_net_ops = {
.init = tcpv6_net_init,
.exit = tcpv6_net_exit,
.exit_batch = tcpv6_net_exit_batch,
};
int __init tcpv6_init(void)
......
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