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Commit 4ea0c32f authored by Xin Long's avatar Xin Long Committed by David S. Miller
Browse files

sctp: add support for MSG_MORE 

This patch is to add support for MSG_MORE on sctp.

It adds force_delay in sctp_datamsg to save MSG_MORE, and sets it after
creating datamsg according to the send flag. sctp_packet_can_append_data
then uses it to decide if the chunks of this msg will be sent at once or
delay it.

Note that unlike [1], this patch saves MSG_MORE in datamsg, instead of
in assoc. As sctp enqueues the chunks first, then dequeue them one by
one. If it's saved in assoc,the current msg's send flag (MSG_MORE) may
affect other chunks' bundling.

Since last patch, sctp flush out queue once assoc state falls into
SHUTDOWN_PENDING, the close block problem mentioned in [1] has been
solved as well.

[1] https://patchwork.ozlabs.org/patch/372404/



Signed-off-by: default avatarXin Long <lucien.xin@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b7018d0b

include/net/sctp/structs.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -497,6 +497,7 @@ struct sctp_datamsg { 
	/* Did the messenge fail to send? */

	/* Did the messenge fail to send? */

	int send_error;

	int send_error;

	u8 send_failed:1,

	u8 send_failed:1,

	   force_delay:1,

	   can_delay;	    /* should this message be Nagle delayed */

	   can_delay;	    /* should this message be Nagle delayed */

};

};

net/sctp/output.c

+3 −6
Original line number Original line Diff line number Diff line
@@ -704,18 +704,15 @@ static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet, 
	 * unacknowledged.

	 * unacknowledged.

	 */

	 */





	if (sctp_sk(asoc->base.sk)->nodelay)

	if ((sctp_sk(asoc->base.sk)->nodelay || inflight == 0) &&

		/* Nagle disabled */

	    !chunk->msg->force_delay)

		/* Nothing unacked */

		return SCTP_XMIT_OK;

		return SCTP_XMIT_OK;





	if (!sctp_packet_empty(packet))

	if (!sctp_packet_empty(packet))

		/* Append to packet */

		/* Append to packet */

		return SCTP_XMIT_OK;

		return SCTP_XMIT_OK;





	if (inflight == 0)

		/* Nothing unacked */

		return SCTP_XMIT_OK;



	if (!sctp_state(asoc, ESTABLISHED))

	if (!sctp_state(asoc, ESTABLISHED))

		return SCTP_XMIT_OK;

		return SCTP_XMIT_OK;

net/sctp/socket.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -1964,6 +1964,7 @@ static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len) 
		err = PTR_ERR(datamsg);

		err = PTR_ERR(datamsg);

		goto out_free;

		goto out_free;

	}

	}

	datamsg->force_delay = !!(msg->msg_flags & MSG_MORE);





	/* Now send the (possibly) fragmented message. */

	/* Now send the (possibly) fragmented message. */

	list_for_each_entry(chunk, &datamsg->chunks, frag_list) {

	list_for_each_entry(chunk, &datamsg->chunks, frag_list) {