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Message-Id: <20200326204640.67336-13-mathew.j.martineau@linux.intel.com>
Date: Thu, 26 Mar 2020 13:46:35 -0700
From: Mat Martineau <mathew.j.martineau@...ux.intel.com>
To: netdev@...r.kernel.org
Cc: Paolo Abeni <pabeni@...hat.com>, eric.dumazet@...il.com,
Mat Martineau <mathew.j.martineau@...ux.intel.com>
Subject: [PATCH net-next v2 12/17] mptcp: implement and use MPTCP-level retransmission
From: Paolo Abeni <pabeni@...hat.com>
On timeout event, schedule a work queue to do the retransmission.
Retransmission code closely resembles the sendmsg() implementation and
re-uses mptcp_sendmsg_frag, providing a dummy msghdr - for flags'
sake - and peeking the relevant dfrag from the rtx head.
Signed-off-by: Paolo Abeni <pabeni@...hat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@...ux.intel.com>
---
net/mptcp/protocol.c | 98 ++++++++++++++++++++++++++++++++++++++++++--
net/mptcp/protocol.h | 1 +
2 files changed, 95 insertions(+), 4 deletions(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 7bdf79f8787a..e72c7322637f 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -283,6 +283,10 @@ static void mptcp_reset_timer(struct sock *sk)
void mptcp_data_acked(struct sock *sk)
{
mptcp_reset_timer(sk);
+
+ if (!sk_stream_is_writeable(sk) &&
+ schedule_work(&mptcp_sk(sk)->work))
+ sock_hold(sk);
}
static void mptcp_stop_timer(struct sock *sk)
@@ -900,10 +904,13 @@ static void mptcp_retransmit_handler(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
- if (atomic64_read(&msk->snd_una) == msk->write_seq)
+ if (atomic64_read(&msk->snd_una) == msk->write_seq) {
mptcp_stop_timer(sk);
- else
- mptcp_reset_timer(sk);
+ } else {
+ set_bit(MPTCP_WORK_RTX, &msk->flags);
+ if (schedule_work(&msk->work))
+ sock_hold(sk);
+ }
}
static void mptcp_retransmit_timer(struct timer_list *t)
@@ -925,6 +932,37 @@ static void mptcp_retransmit_timer(struct timer_list *t)
sock_put(sk);
}
+/* Find an idle subflow. Return NULL if there is unacked data at tcp
+ * level.
+ *
+ * A backup subflow is returned only if that is the only kind available.
+ */
+static struct sock *mptcp_subflow_get_retrans(const struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct sock *backup = NULL;
+
+ sock_owned_by_me((const struct sock *)msk);
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ /* still data outstanding at TCP level? Don't retransmit. */
+ if (!tcp_write_queue_empty(ssk))
+ return NULL;
+
+ if (subflow->backup) {
+ if (!backup)
+ backup = ssk;
+ continue;
+ }
+
+ return ssk;
+ }
+
+ return backup;
+}
+
/* subflow sockets can be either outgoing (connect) or incoming
* (accept).
*
@@ -958,11 +996,62 @@ static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
static void mptcp_worker(struct work_struct *work)
{
struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
- struct sock *sk = &msk->sk.icsk_inet.sk;
+ struct sock *ssk, *sk = &msk->sk.icsk_inet.sk;
+ int orig_len, orig_offset, ret, mss_now = 0, size_goal = 0;
+ struct mptcp_data_frag *dfrag;
+ u64 orig_write_seq;
+ size_t copied = 0;
+ struct msghdr msg;
+ long timeo = 0;
lock_sock(sk);
+ mptcp_clean_una(sk);
__mptcp_flush_join_list(msk);
__mptcp_move_skbs(msk);
+
+ if (!test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
+ goto unlock;
+
+ dfrag = mptcp_rtx_head(sk);
+ if (!dfrag)
+ goto unlock;
+
+ ssk = mptcp_subflow_get_retrans(msk);
+ if (!ssk)
+ goto reset_unlock;
+
+ lock_sock(ssk);
+
+ msg.msg_flags = MSG_DONTWAIT;
+ orig_len = dfrag->data_len;
+ orig_offset = dfrag->offset;
+ orig_write_seq = dfrag->data_seq;
+ while (dfrag->data_len > 0) {
+ ret = mptcp_sendmsg_frag(sk, ssk, &msg, dfrag, &timeo, &mss_now,
+ &size_goal);
+ if (ret < 0)
+ break;
+
+ copied += ret;
+ dfrag->data_len -= ret;
+ dfrag->offset += ret;
+ }
+ if (copied)
+ tcp_push(ssk, msg.msg_flags, mss_now, tcp_sk(ssk)->nonagle,
+ size_goal);
+
+ dfrag->data_seq = orig_write_seq;
+ dfrag->offset = orig_offset;
+ dfrag->data_len = orig_len;
+
+ mptcp_set_timeout(sk, ssk);
+ release_sock(ssk);
+
+reset_unlock:
+ if (!mptcp_timer_pending(sk))
+ mptcp_reset_timer(sk);
+
+unlock:
release_sock(sk);
sock_put(sk);
}
@@ -1124,6 +1213,7 @@ static int mptcp_disconnect(struct sock *sk, int flags)
lock_sock(sk);
__mptcp_clear_xmit(sk);
release_sock(sk);
+ mptcp_cancel_work(sk);
return tcp_disconnect(sk, flags);
}
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index f855c954a8ff..e9d4a852c7f1 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -88,6 +88,7 @@
/* MPTCP socket flags */
#define MPTCP_DATA_READY 0
#define MPTCP_SEND_SPACE 1
+#define MPTCP_WORK_RTX 2
static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field)
{
--
2.26.0
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