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mptcp: trigger msk processing even for OoO data

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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@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2020-09-14 10:01:09 +02:00 committed by David S. Miller
parent 47bebdf365
commit 6719331c2f
3 changed files with 78 additions and 42 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

33
net/mptcp/protocol.c
View file

@ -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);

9
net/mptcp/protocol.h
View file

@ -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 */

78
net/mptcp/subflow.c
View file

@ -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;