Commit 759af00e authored Jan 22, 2009 by Vlad Yasevich Committed by David S. Miller Jan 22, 2009

sctp: Properly timestamp outgoing data chunks for rtx purposes



Recent changes to the retransmit code exposed a long standing
bug where it was possible for a chunk to be time stamped
after the retransmit timer was reset.  This caused a rare
situation where the retrnamist timer has expired, but
nothing was marked for retrnasmission because all of
timesamps on data were less then 1 rto ago.  As result,
the timer was never restarted since nothing was retransmitted,
and this resulted in a hung association that did couldn't
complete the data transfer.  The solution is to timestamp
the chunk when it's added to the packet for transmission
purposes.  After the packet is trsnmitted the rtx timer
is restarted.  This guarantees that when the timer expires,
there will be data to retransmit.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 6574df9a

net/sctp/output.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -324,14 +324,16 @@ append:
		switch (chunk->chunk_hdr->type) {
		case SCTP_CID_DATA:
		retval = sctp_packet_append_data(packet, chunk);
		if (SCTP_XMIT_OK != retval)
		goto finish;
		/* Disallow SACK bundling after DATA. */
		packet->has_sack = 1;
		/* Disallow AUTH bundling after DATA */
		packet->has_auth = 1;
		/* Let it be knows that packet has DATA in it */
		packet->has_data = 1;
		if (SCTP_XMIT_OK != retval)
		goto finish;
		/* timestamp the chunk for rtx purposes */
		chunk->sent_at = jiffies;
		break;
		case SCTP_CID_COOKIE_ECHO:
		packet->has_cookie_echo = 1;
		@@ -470,7 +472,6 @@ int sctp_packet_transmit(struct sctp_packet *packet)
		} else
		chunk->resent = 1;

		chunk->sent_at = jiffies;
		has_data = 1;
		}

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