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Message-Id: <2a05880d191b0859f52bbcc002cd694603cd36b8.1599854632.git.pabeni@redhat.com>
Date: Mon, 14 Sep 2020 10:01:09 +0200
From: Paolo Abeni <pabeni@...hat.com>
To: netdev@...r.kernel.org
Cc: "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>, mptcp@...ts.01.org
Subject: [PATCH net-next v2 03/13] mptcp: trigger msk processing even for OoO data
This is a prerequisite to allow receiving data from multiple
subflows without re-injection.
Instead of dropping the OoO - "future" data in
subflow_check_data_avail(), call into __mptcp_move_skbs()
and let the msk drop that.
To avoid code duplication factor out the mptcp_subflow_discard_data()
helper.
Note that __mptcp_move_skbs() can now find multiple subflows
with data avail (comprising to-be-discarded data), so must
update the byte counter incrementally.
v1 -> v2:
- fix checkpatch issues (unsigned -> unsigned int)
Signed-off-by: Paolo Abeni <pabeni@...hat.com>
---
net/mptcp/protocol.c | 33 +++++++++++++++----
net/mptcp/protocol.h | 9 ++++-
net/mptcp/subflow.c | 78 ++++++++++++++++++++++++--------------------
3 files changed, 78 insertions(+), 42 deletions(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 854a8b3b9ecd..95573c6f7762 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -167,7 +167,8 @@ static bool mptcp_subflow_dsn_valid(const struct mptcp_sock *msk,
return true;
subflow->data_avail = 0;
- return mptcp_subflow_data_available(ssk);
+ mptcp_subflow_data_available(ssk);
+ return subflow->data_avail == MPTCP_SUBFLOW_DATA_AVAIL;
}
static void mptcp_check_data_fin_ack(struct sock *sk)
@@ -313,11 +314,18 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
struct tcp_sock *tp;
bool done = false;
- if (!mptcp_subflow_dsn_valid(msk, ssk)) {
- *bytes = 0;
+ pr_debug("msk=%p ssk=%p data avail=%d valid=%d empty=%d",
+ msk, ssk, subflow->data_avail,
+ mptcp_subflow_dsn_valid(msk, ssk),
+ !skb_peek(&ssk->sk_receive_queue));
+ if (subflow->data_avail == MPTCP_SUBFLOW_OOO_DATA) {
+ mptcp_subflow_discard_data(ssk, subflow->map_data_len);
return false;
}
+ if (!mptcp_subflow_dsn_valid(msk, ssk))
+ return false;
+
tp = tcp_sk(ssk);
do {
u32 map_remaining, offset;
@@ -376,7 +384,7 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
}
} while (more_data_avail);
- *bytes = moved;
+ *bytes += moved;
/* If the moves have caught up with the DATA_FIN sequence number
* it's time to ack the DATA_FIN and change socket state, but
@@ -415,9 +423,17 @@ static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
void mptcp_data_ready(struct sock *sk, struct sock *ssk)
{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
struct mptcp_sock *msk = mptcp_sk(sk);
+ bool wake;
- set_bit(MPTCP_DATA_READY, &msk->flags);
+ /* move_skbs_to_msk below can legitly clear the data_avail flag,
+ * but we will need later to properly woke the reader, cache its
+ * value
+ */
+ wake = subflow->data_avail == MPTCP_SUBFLOW_DATA_AVAIL;
+ if (wake)
+ set_bit(MPTCP_DATA_READY, &msk->flags);
if (atomic_read(&sk->sk_rmem_alloc) < READ_ONCE(sk->sk_rcvbuf) &&
move_skbs_to_msk(msk, ssk))
@@ -438,7 +454,8 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk)
move_skbs_to_msk(msk, ssk);
}
wake:
- sk->sk_data_ready(sk);
+ if (wake)
+ sk->sk_data_ready(sk);
}
static void __mptcp_flush_join_list(struct mptcp_sock *msk)
@@ -1281,6 +1298,9 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
set_bit(MPTCP_DATA_READY, &msk->flags);
}
out_err:
+ pr_debug("msk=%p data_ready=%d rx queue empty=%d copied=%d",
+ msk, test_bit(MPTCP_DATA_READY, &msk->flags),
+ skb_queue_empty(&sk->sk_receive_queue), copied);
mptcp_rcv_space_adjust(msk, copied);
release_sock(sk);
@@ -2308,6 +2328,7 @@ static __poll_t mptcp_poll(struct file *file, struct socket *sock,
sock_poll_wait(file, sock, wait);
state = inet_sk_state_load(sk);
+ pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags);
if (state == TCP_LISTEN)
return mptcp_check_readable(msk);
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 60b27d44c184..794997852c5e 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -268,6 +268,12 @@ mptcp_subflow_rsk(const struct request_sock *rsk)
return (struct mptcp_subflow_request_sock *)rsk;
}
+enum mptcp_data_avail {
+ MPTCP_SUBFLOW_NODATA,
+ MPTCP_SUBFLOW_DATA_AVAIL,
+ MPTCP_SUBFLOW_OOO_DATA
+};
+
/* MPTCP subflow context */
struct mptcp_subflow_context {
struct list_head node;/* conn_list of subflows */
@@ -292,10 +298,10 @@ struct mptcp_subflow_context {
map_valid : 1,
mpc_map : 1,
backup : 1,
- data_avail : 1,
rx_eof : 1,
use_64bit_ack : 1, /* Set when we received a 64-bit DSN */
can_ack : 1; /* only after processing the remote a key */
+ enum mptcp_data_avail data_avail;
u32 remote_nonce;
u64 thmac;
u32 local_nonce;
@@ -347,6 +353,7 @@ int mptcp_is_enabled(struct net *net);
void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
struct mptcp_options_received *mp_opt);
bool mptcp_subflow_data_available(struct sock *sk);
+int mptcp_subflow_discard_data(struct sock *sk, unsigned int limit);
void __init mptcp_subflow_init(void);
/* called with sk socket lock held */
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 53b455c3c229..071ee54b3c9f 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -816,6 +816,40 @@ static int subflow_read_actor(read_descriptor_t *desc,
return copy_len;
}
+int mptcp_subflow_discard_data(struct sock *ssk, unsigned int limit)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ u32 map_remaining;
+ size_t delta;
+
+ map_remaining = subflow->map_data_len -
+ mptcp_subflow_get_map_offset(subflow);
+ delta = min_t(size_t, limit, map_remaining);
+
+ /* discard mapped data */
+ pr_debug("discarding %zu bytes, current map len=%d", delta,
+ map_remaining);
+ if (delta) {
+ read_descriptor_t desc = {
+ .count = delta,
+ };
+ int ret;
+
+ ret = tcp_read_sock(ssk, &desc, subflow_read_actor);
+ if (ret < 0) {
+ ssk->sk_err = -ret;
+ return ret;
+ }
+ if (ret < delta)
+ return 0;
+ if (delta == map_remaining) {
+ subflow->data_avail = 0;
+ subflow->map_valid = 0;
+ }
+ }
+ return 0;
+}
+
static bool subflow_check_data_avail(struct sock *ssk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
@@ -832,8 +866,6 @@ static bool subflow_check_data_avail(struct sock *ssk)
msk = mptcp_sk(subflow->conn);
for (;;) {
- u32 map_remaining;
- size_t delta;
u64 ack_seq;
u64 old_ack;
@@ -851,7 +883,7 @@ static bool subflow_check_data_avail(struct sock *ssk)
subflow->map_data_len = skb->len;
subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq -
subflow->ssn_offset;
- subflow->data_avail = 1;
+ subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;
return true;
}
@@ -880,43 +912,19 @@ static bool subflow_check_data_avail(struct sock *ssk)
pr_debug("msk ack_seq=%llx subflow ack_seq=%llx", old_ack,
ack_seq);
if (ack_seq == old_ack) {
- subflow->data_avail = 1;
+ subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;
+ break;
+ } else if (after64(ack_seq, old_ack)) {
+ subflow->data_avail = MPTCP_SUBFLOW_OOO_DATA;
break;
}
/* only accept in-sequence mapping. Old values are spurious
- * retransmission; we can hit "future" values on active backup
- * subflow switch, we relay on retransmissions to get
- * in-sequence data.
- * Cuncurrent subflows support will require subflow data
- * reordering
+ * retransmission
*/
- map_remaining = subflow->map_data_len -
- mptcp_subflow_get_map_offset(subflow);
- if (before64(ack_seq, old_ack))
- delta = min_t(size_t, old_ack - ack_seq, map_remaining);
- else
- delta = min_t(size_t, ack_seq - old_ack, map_remaining);
-
- /* discard mapped data */
- pr_debug("discarding %zu bytes, current map len=%d", delta,
- map_remaining);
- if (delta) {
- read_descriptor_t desc = {
- .count = delta,
- };
- int ret;
-
- ret = tcp_read_sock(ssk, &desc, subflow_read_actor);
- if (ret < 0) {
- ssk->sk_err = -ret;
- goto fatal;
- }
- if (ret < delta)
- return false;
- if (delta == map_remaining)
- subflow->map_valid = 0;
- }
+ if (mptcp_subflow_discard_data(ssk, old_ack - ack_seq))
+ goto fatal;
+ return false;
}
return true;
--
2.26.2
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