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Date: Tue, 28 Jul 2020 15:12:03 -0700
From: Mat Martineau <mathew.j.martineau@...ux.intel.com>
To: netdev@...r.kernel.org
Cc: Mat Martineau <mathew.j.martineau@...ux.intel.com>,
mptcp@...ts.01.org, matthieu.baerts@...sares.net, pabeni@...hat.com
Subject: [PATCH net-next 05/12] mptcp: Track received DATA_FIN sequence number and add related helpers
Incoming DATA_FIN headers need to propagate the presence of the DATA_FIN
bit and the associated sequence number to the MPTCP layer, even when
arriving on a bare ACK that does not get added to the receive queue. Add
structure members to store the DATA_FIN information and helpers to set
and check those values.
Signed-off-by: Mat Martineau <mathew.j.martineau@...ux.intel.com>
---
net/mptcp/options.c | 16 +++++++
net/mptcp/protocol.c | 106 +++++++++++++++++++++++++++++++++++++++----
net/mptcp/protocol.h | 3 ++
3 files changed, 115 insertions(+), 10 deletions(-)
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index f157cb7e14c0..38583d1b9b5f 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -782,6 +782,22 @@ static void update_una(struct mptcp_sock *msk,
}
}
+bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq)
+{
+ /* Skip if DATA_FIN was already received.
+ * If updating simultaneously with the recvmsg loop, values
+ * should match. If they mismatch, the peer is misbehaving and
+ * we will prefer the most recent information.
+ */
+ if (READ_ONCE(msk->rcv_data_fin) || !READ_ONCE(msk->first))
+ return false;
+
+ WRITE_ONCE(msk->rcv_data_fin_seq, data_fin_seq);
+ WRITE_ONCE(msk->rcv_data_fin, 1);
+
+ return true;
+}
+
static bool add_addr_hmac_valid(struct mptcp_sock *msk,
struct mptcp_options_received *mp_opt)
{
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index dd403ba3679a..e1c71bfd61a3 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -16,6 +16,7 @@
#include <net/inet_hashtables.h>
#include <net/protocol.h>
#include <net/tcp.h>
+#include <net/tcp_states.h>
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
#include <net/transp_v6.h>
#endif
@@ -163,6 +164,101 @@ static bool mptcp_subflow_dsn_valid(const struct mptcp_sock *msk,
return mptcp_subflow_data_available(ssk);
}
+static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ if (READ_ONCE(msk->rcv_data_fin) &&
+ ((1 << sk->sk_state) &
+ (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) {
+ u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq);
+
+ if (msk->ack_seq == rcv_data_fin_seq) {
+ if (seq)
+ *seq = rcv_data_fin_seq;
+
+ return true;
+ }
+ }
+
+ return false;
+}
+
+static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk)
+{
+ long tout = ssk && inet_csk(ssk)->icsk_pending ?
+ inet_csk(ssk)->icsk_timeout - jiffies : 0;
+
+ if (tout <= 0)
+ tout = mptcp_sk(sk)->timer_ival;
+ mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
+}
+
+static void mptcp_check_data_fin(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ u64 rcv_data_fin_seq;
+
+ if (__mptcp_check_fallback(msk) || !msk->first)
+ return;
+
+ /* Need to ack a DATA_FIN received from a peer while this side
+ * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2.
+ * msk->rcv_data_fin was set when parsing the incoming options
+ * at the subflow level and the msk lock was not held, so this
+ * is the first opportunity to act on the DATA_FIN and change
+ * the msk state.
+ *
+ * If we are caught up to the sequence number of the incoming
+ * DATA_FIN, send the DATA_ACK now and do state transition. If
+ * not caught up, do nothing and let the recv code send DATA_ACK
+ * when catching up.
+ */
+
+ if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) {
+ struct mptcp_subflow_context *subflow;
+
+ msk->ack_seq++;
+ WRITE_ONCE(msk->rcv_data_fin, 0);
+
+ sk->sk_shutdown |= RCV_SHUTDOWN;
+
+ switch (sk->sk_state) {
+ case TCP_ESTABLISHED:
+ inet_sk_state_store(sk, TCP_CLOSE_WAIT);
+ break;
+ case TCP_FIN_WAIT1:
+ inet_sk_state_store(sk, TCP_CLOSING);
+ break;
+ case TCP_FIN_WAIT2:
+ inet_sk_state_store(sk, TCP_CLOSE);
+ // @@ Close subflows now?
+ break;
+ default:
+ /* Other states not expected */
+ WARN_ON_ONCE(1);
+ break;
+ }
+
+ mptcp_set_timeout(sk, NULL);
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ lock_sock(ssk);
+ tcp_send_ack(ssk);
+ release_sock(ssk);
+ }
+
+ sk->sk_state_change(sk);
+
+ if (sk->sk_shutdown == SHUTDOWN_MASK ||
+ sk->sk_state == TCP_CLOSE)
+ sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
+ else
+ sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
+ }
+}
+
static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
struct sock *ssk,
unsigned int *bytes)
@@ -303,16 +399,6 @@ static void __mptcp_flush_join_list(struct mptcp_sock *msk)
spin_unlock_bh(&msk->join_list_lock);
}
-static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk)
-{
- long tout = ssk && inet_csk(ssk)->icsk_pending ?
- inet_csk(ssk)->icsk_timeout - jiffies : 0;
-
- if (tout <= 0)
- tout = mptcp_sk(sk)->timer_ival;
- mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
-}
-
static bool mptcp_timer_pending(struct sock *sk)
{
return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 3f49cc105772..beb34b8a5363 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -193,12 +193,14 @@ struct mptcp_sock {
u64 remote_key;
u64 write_seq;
u64 ack_seq;
+ u64 rcv_data_fin_seq;
atomic64_t snd_una;
unsigned long timer_ival;
u32 token;
unsigned long flags;
bool can_ack;
bool fully_established;
+ bool rcv_data_fin;
bool snd_data_fin_enable;
spinlock_t join_list_lock;
struct work_struct work;
@@ -385,6 +387,7 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk);
bool mptcp_finish_join(struct sock *sk);
void mptcp_data_acked(struct sock *sk);
void mptcp_subflow_eof(struct sock *sk);
+bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq);
void __init mptcp_token_init(void);
static inline void mptcp_token_init_request(struct request_sock *req)
--
2.28.0
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