This patch implement the sender side for SACK-IMMEDIATELY
extension.
Section 4.1. Sender Side Considerations
Whenever the sender of a DATA chunk can benefit from the
corresponding SACK chunk being sent back without delay, the sender
MAY set the I-bit in the DATA chunk header.
Reasons for setting the I-bit include
o The sender has not enough queued user data to send the remaining
DATA chunks due to the Nagle algorithm.
o The sending of a DATA chunk fills the congestion or receiver
window.
o The sender is in the SHUTDOWN-PENDING state.
Signed-off-by: Wei Yongjun <yjwei@xxxxxxxxxxxxxx>
---
include/net/sctp/structs.h | 2 ++
net/sctp/output.c | 12 ++++++++++++
net/sctp/outqueue.c | 19 ++++++++++++++++++-
3 files changed, 32 insertions(+), 1 deletions(-)
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 42d00ce..54ac504 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -764,6 +764,7 @@ struct sctp_chunk {
has_asconf:1, /* IN: have seen an asconf before */
tsn_missing_report:2, /* Data chunk missing counter. */
fast_retransmit:2; /* Is this chunk fast retransmitted? */
+ unsigned nagle_qlen; /* Queued data length due to Nagle. */
};
void sctp_chunk_hold(struct sctp_chunk *);
@@ -826,6 +827,7 @@ struct sctp_packet {
has_sack:1, /* This packet contains a SACK chunk. */
has_auth:1, /* This packet contains an AUTH chunk */
has_data:1, /* This packet contains at least 1 DATA chunk */
+ has_iflag:1, /* This packet need I-Flag for last DATA chunk */
ipfragok:1, /* So let ip fragment this packet */
malloced:1; /* Is it malloced? */
};
diff --git a/net/sctp/output.c b/net/sctp/output.c
index 951f586..aad3ff5 100644
--- a/net/sctp/output.c
+++ b/net/sctp/output.c
@@ -75,6 +75,7 @@ static void sctp_packet_reset(struct sctp_packet *packet)
packet->has_cookie_echo = 0;
packet->has_sack = 0;
packet->has_data = 0;
+ packet->has_iflag = 0;
packet->has_auth = 0;
packet->ipfragok = 0;
packet->auth = NULL;
@@ -447,6 +448,10 @@ int sctp_packet_transmit(struct sctp_packet *packet)
} else
chunk->resent = 1;
+ if (packet->has_iflag &&
+ list_empty(&packet->chunk_list))
+ chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM;
+
has_data = 1;
}
@@ -743,6 +748,13 @@ static void sctp_packet_append_data(struct sctp_packet *packet,
else
rwnd = 0;
+ /* Reasons for setting the I-bit include
+ * - The sending of a DATA chunk fills the congestion or
+ * receiver window.
+ */
+ if (rwnd == 0 || transport->flight_size >= transport->cwnd)
+ packet->has_iflag = 1;
+
asoc->peer.rwnd = rwnd;
/* Has been accepted for transmission. */
if (!asoc->peer.prsctp_capable)
diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index c9f20e2..1193169 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -995,10 +995,21 @@ static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
/* Add the chunk to the packet. */
status = sctp_packet_transmit_chunk(packet, chunk, 0);
+ /* The sender is in the SHUTDOWN-PENDING state,
+ * The sender MAY set the I-bit in the DATA
+ * chunk header.
+ */
+ if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING)
+ packet->has_iflag = 1;
+
switch (status) {
+ case SCTP_XMIT_NAGLE_DELAY:
+ /* mark this chunks not be sent due to Nagle
+ * algorithm
+ */
+ chunk->nagle_qlen = q->out_qlen + 1;
case SCTP_XMIT_PMTU_FULL:
case SCTP_XMIT_RWND_FULL:
- case SCTP_XMIT_NAGLE_DELAY:
/* We could not append this chunk, so put
* the chunk back on the output queue.
*/
@@ -1011,6 +1022,12 @@ static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
break;
case SCTP_XMIT_OK:
+ /* The sender has not enough queued user data
+ * to send the remaining DATA chunks due to the
+ * Nagle algorithm.
+ */
+ if (chunk->nagle_qlen == q->out_qlen + 1)
+ packet->has_iflag = 1;
break;
default:
--
1.6.2.2
--
To unsubscribe from this list: send the line "unsubscribe linux-sctp" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
