Commit 8dbdf1f5 authored by Xin Long's avatar Xin Long Committed by David S. Miller
Browse files

sctp: implement prsctp PRIO policy 



prsctp PRIO policy is a policy to abandon lower priority chunks when
asoc doesn't have enough snd buffer, so that the current chunk with
higher priority can be queued successfully.

Similar to TTL/RTX policy, we will set the priority of the chunk to
prsctp_param with sinfo->sinfo_timetolive in sctp_set_prsctp_policy().
So if PRIO policy is enabled, msg->expire_at won't work.

asoc->sent_cnt_removable will record how many chunks can be checked to
remove. If priority policy is enabled, when the chunk is queued into
the out_queue, we will increase sent_cnt_removable. When the chunk is
moved to abandon_queue or dequeue and free, we will decrease
sent_cnt_removable.

In sctp_sendmsg, we will check if there is enough snd buffer for current
msg and if sent_cnt_removable is not 0. Then try to abandon chunks in
sctp_prune_prsctp when sendmsg from the retransmit/transmited queue, and
free chunks from out_queue in right order until the abandon+free size >
msg_len - sctp_wfree. For the abandon size, we have to wait until it
sends FORWARD TSN, receives the sack and the chunks are really freed.

Signed-off-by: default avatarXin Long <lucien.xin@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 01aadb3a

include/net/sctp/structs.h

+4 −0
Original line number Diff line number Diff line
@@ -1084,6 +1084,8 @@ void sctp_retransmit(struct sctp_outq *, struct sctp_transport *, 
		     sctp_retransmit_reason_t);

void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);

int sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);

void sctp_prsctp_prune(struct sctp_association *asoc,

		       struct sctp_sndrcvinfo *sinfo, int msg_len);

/* Uncork and flush an outqueue.  */

static inline void sctp_outq_cork(struct sctp_outq *q)

{
@@ -1864,6 +1866,8 @@ struct sctp_association { 


	struct sctp_priv_assoc_stats stats;



	int sent_cnt_removable;



	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];

	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];

};

net/sctp/chunk.c

+1 −0
Original line number Diff line number Diff line
@@ -360,6 +360,7 @@ int sctp_chunk_abandoned(struct sctp_chunk *chunk) 
		chunk->asoc->abandoned_sent[SCTP_PR_INDEX(RTX)]++;

		return 1;

	}

	/* PRIO policy is processed by sendmsg, not here */



	return 0;

}

net/sctp/outqueue.c

+99 −0
Original line number Diff line number Diff line
@@ -326,6 +326,9 @@ int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk, gfp_t gfp) 


			sctp_chunk_hold(chunk);

			sctp_outq_tail_data(q, chunk);

			if (chunk->asoc->prsctp_enable &&

			    SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags))

				chunk->asoc->sent_cnt_removable++;

			if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)

				SCTP_INC_STATS(net, SCTP_MIB_OUTUNORDERCHUNKS);

			else
@@ -372,6 +375,96 @@ static void sctp_insert_list(struct list_head *head, struct list_head *new) 
		list_add_tail(new, head);

}



static int sctp_prsctp_prune_sent(struct sctp_association *asoc,

				  struct sctp_sndrcvinfo *sinfo,

				  struct list_head *queue, int msg_len)

{

	struct sctp_chunk *chk, *temp;



	list_for_each_entry_safe(chk, temp, queue, transmitted_list) {

		if (!SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) ||

		    chk->prsctp_param <= sinfo->sinfo_timetolive)

			continue;



		list_del_init(&chk->transmitted_list);

		sctp_insert_list(&asoc->outqueue.abandoned,

				 &chk->transmitted_list);



		asoc->sent_cnt_removable--;

		asoc->abandoned_sent[SCTP_PR_INDEX(PRIO)]++;



		if (!chk->tsn_gap_acked) {

			if (chk->transport)

				chk->transport->flight_size -=

						sctp_data_size(chk);

			asoc->outqueue.outstanding_bytes -= sctp_data_size(chk);

		}



		msg_len -= SCTP_DATA_SNDSIZE(chk) +

			   sizeof(struct sk_buff) +

			   sizeof(struct sctp_chunk);

		if (msg_len <= 0)

			break;

	}



	return msg_len;

}



static int sctp_prsctp_prune_unsent(struct sctp_association *asoc,

				    struct sctp_sndrcvinfo *sinfo,

				    struct list_head *queue, int msg_len)

{

	struct sctp_chunk *chk, *temp;



	list_for_each_entry_safe(chk, temp, queue, list) {

		if (!SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) ||

		    chk->prsctp_param <= sinfo->sinfo_timetolive)

			continue;



		list_del_init(&chk->list);

		asoc->sent_cnt_removable--;

		asoc->abandoned_unsent[SCTP_PR_INDEX(PRIO)]++;



		msg_len -= SCTP_DATA_SNDSIZE(chk) +

			   sizeof(struct sk_buff) +

			   sizeof(struct sctp_chunk);

		sctp_chunk_free(chk);

		if (msg_len <= 0)

			break;

	}



	return msg_len;

}



/* Abandon the chunks according their priorities */

void sctp_prsctp_prune(struct sctp_association *asoc,

		       struct sctp_sndrcvinfo *sinfo, int msg_len)

{

	struct sctp_transport *transport;



	if (!asoc->prsctp_enable || !asoc->sent_cnt_removable)

		return;



	msg_len = sctp_prsctp_prune_sent(asoc, sinfo,

					 &asoc->outqueue.retransmit,

					 msg_len);

	if (msg_len <= 0)

		return;



	list_for_each_entry(transport, &asoc->peer.transport_addr_list,

			    transports) {

		msg_len = sctp_prsctp_prune_sent(asoc, sinfo,

						 &transport->transmitted,

						 msg_len);

		if (msg_len <= 0)

			return;

	}



	sctp_prsctp_prune_unsent(asoc, sinfo,

				 &asoc->outqueue.out_chunk_list,

				 msg_len);

}



/* Mark all the eligible packets on a transport for retransmission.  */

void sctp_retransmit_mark(struct sctp_outq *q,

			  struct sctp_transport *transport,
@@ -962,6 +1055,9 @@ static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout, gfp_t gfp) 


				/* Mark as failed send. */

				sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM);

				if (asoc->prsctp_enable &&

				    SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags))

					asoc->sent_cnt_removable--;

				sctp_chunk_free(chunk);

				continue;

			}
@@ -1251,6 +1347,9 @@ int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk) 
		tsn = ntohl(tchunk->subh.data_hdr->tsn);

		if (TSN_lte(tsn, ctsn)) {

			list_del_init(&tchunk->transmitted_list);

			if (asoc->prsctp_enable &&

			    SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags))

				asoc->sent_cnt_removable--;

			sctp_chunk_free(tchunk);

		}

	}

net/sctp/sm_make_chunk.c

+2 −1
Original line number Diff line number Diff line
@@ -720,7 +720,8 @@ static void sctp_set_prsctp_policy(struct sctp_chunk *chunk, 
	if (SCTP_PR_TTL_ENABLED(sinfo->sinfo_flags))

		chunk->prsctp_param =

			jiffies + msecs_to_jiffies(sinfo->sinfo_timetolive);

	else if (SCTP_PR_RTX_ENABLED(sinfo->sinfo_flags))

	else if (SCTP_PR_RTX_ENABLED(sinfo->sinfo_flags) ||

		 SCTP_PR_PRIO_ENABLED(sinfo->sinfo_flags))

		chunk->prsctp_param = sinfo->sinfo_timetolive;

}

net/sctp/socket.c

+3 −0
Original line number Diff line number Diff line
@@ -1914,6 +1914,9 @@ static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len) 
		goto out_free;

	}



	if (sctp_wspace(asoc) < msg_len)

		sctp_prsctp_prune(asoc, sinfo, msg_len - sctp_wspace(asoc));



	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);

	if (!sctp_wspace(asoc)) {

		err = sctp_wait_for_sndbuf(asoc, &timeo, msg_len);

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