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Message-Id: <20220512211456.2680273-1-eric.dumazet@gmail.com>
Date: Thu, 12 May 2022 14:14:56 -0700
From: Eric Dumazet <eric.dumazet@...il.com>
To: "David S . Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>
Cc: netdev <netdev@...r.kernel.org>,
Eric Dumazet <edumazet@...gle.com>,
Eric Dumazet <eric.dumazet@...il.com>,
Leonard Crestez <cdleonard@...il.com>
Subject: [PATCH net] Revert "tcp/dccp: get rid of inet_twsk_purge()"
From: Eric Dumazet <edumazet@...gle.com>
This reverts commits:
0dad4087a86a2cbe177404dc73f18ada26a2c390 ("tcp/dccp: get rid of inet_twsk_purge()")
d507204d3c5cc57d9a8bdf0a477615bb59ea1611 ("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: 0dad4087a86a ("tcp/dccp: get rid of inet_twsk_purge()")
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Reported-by: Leonard Crestez <cdleonard@...il.com>
---
include/net/inet_timewait_sock.h | 3 +-
net/dccp/ipv4.c | 6 ++++
net/dccp/ipv6.c | 6 ++++
net/ipv4/inet_timewait_sock.c | 58 ++++++++++++++++++++++++++++----
net/ipv4/tcp_ipv4.c | 2 ++
net/ipv6/tcp_ipv6.c | 6 ++++
6 files changed, 73 insertions(+), 8 deletions(-)
diff --git a/include/net/inet_timewait_sock.h b/include/net/inet_timewait_sock.h
index 463ae5d33eb09c40caeb4d039af268609b5e563b..5b47545f22d39eb2dd9725ac37bd7d7a9016a03c 100644
--- a/include/net/inet_timewait_sock.h
+++ b/include/net/inet_timewait_sock.h
@@ -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)
{
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index ae662567a6cb6a440c79a9805a2cd6d146ac5a29..0ea29270d7e53730d14ec43654be8f956f891552 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -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),
};
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index eab3bd1ee9a0a0064c04ff97fd8363e60daa0079..fa663518fa0e465458b7486ad0cd0672425f08b0 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -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),
};
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index 9e0bbd02656013e6e8be5765a7b86fc16e6bf831..0ec501845cb3bb51082f8091b4e0ebb32f83bf33 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -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);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index f9cec624068dfa1d218357d7e88c89459d7d54f4..457f5b5d5d4a95c06eca82db1dbe7822cb4d040c 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -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);
}
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 13678d3908fac9990e5b0c0df87fa4cca685baaf..faaddaf43c90b96e7a2bc9fbad7941ae5ada1b3c 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -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)
--
2.36.0.550.gb090851708-goog
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