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Commit 692787ce authored by Xin Long's avatar Xin Long Committed by David S. Miller
Browse files

sctp: implement receiver-side procedures for the SSN/TSN Reset Request Parameter 



This patch is to implement Receiver-Side Procedures for the SSN/TSN
Reset Request Parameter described in rfc6525 section 6.2.4.

The process is kind of complicate, it's wonth having some comments
from section 6.2.4 in the codes.

Signed-off-by: default avatarXin Long <lucien.xin@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c95129d1

include/net/sctp/sm.h

+4 −0
Original line number Diff line number Diff line
@@ -293,6 +293,10 @@ struct sctp_chunk *sctp_process_strreset_inreq( 
				struct sctp_association *asoc,

				union sctp_params param,

				struct sctp_ulpevent **evp);

struct sctp_chunk *sctp_process_strreset_tsnreq(

				struct sctp_association *asoc,

				union sctp_params param,

				struct sctp_ulpevent **evp);



/* Prototypes for statetable processing. */

net/sctp/sm_statefuns.c

+3 −0
Original line number Diff line number Diff line
@@ -3872,6 +3872,9 @@ sctp_disposition_t sctp_sf_do_reconf(struct net *net, 
		else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST)

			reply = sctp_process_strreset_inreq(

				(struct sctp_association *)asoc, param, &ev);

		else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST)

			reply = sctp_process_strreset_tsnreq(

				(struct sctp_association *)asoc, param, &ev);

		/* More handles for other types will be added here, by now it

		 * just ignores other types.

		 */

net/sctp/stream.c

+79 −0
Original line number Diff line number Diff line
@@ -477,3 +477,82 @@ struct sctp_chunk *sctp_process_strreset_inreq( 


	return chunk;

}



struct sctp_chunk *sctp_process_strreset_tsnreq(

				struct sctp_association *asoc,

				union sctp_params param,

				struct sctp_ulpevent **evp)

{

	__u32 init_tsn = 0, next_tsn = 0, max_tsn_seen;

	struct sctp_strreset_tsnreq *tsnreq = param.v;

	struct sctp_stream *stream = asoc->stream;

	__u32 result = SCTP_STRRESET_DENIED;

	__u32 request_seq;

	__u16 i;



	request_seq = ntohl(tsnreq->request_seq);

	if (request_seq > asoc->strreset_inseq) {

		result = SCTP_STRRESET_ERR_BAD_SEQNO;

		goto out;

	} else if (request_seq == asoc->strreset_inseq) {

		asoc->strreset_inseq++;

	}



	if (!(asoc->strreset_enable & SCTP_ENABLE_RESET_ASSOC_REQ))

		goto out;



	if (asoc->strreset_outstanding) {

		result = SCTP_STRRESET_ERR_IN_PROGRESS;

		goto out;

	}



	/* G3: The same processing as though a SACK chunk with no gap report

	 *     and a cumulative TSN ACK of the Sender's Next TSN minus 1 were

	 *     received MUST be performed.

	 */

	max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);

	sctp_ulpq_reasm_flushtsn(&asoc->ulpq, max_tsn_seen);

	sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);



	/* G1: Compute an appropriate value for the Receiver's Next TSN -- the

	 *     TSN that the peer should use to send the next DATA chunk.  The

	 *     value SHOULD be the smallest TSN not acknowledged by the

	 *     receiver of the request plus 2^31.

	 */

	init_tsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + (1 << 31);

	sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,

			 init_tsn, GFP_ATOMIC);



	/* G4: The same processing as though a FWD-TSN chunk (as defined in

	 *     [RFC3758]) with all streams affected and a new cumulative TSN

	 *     ACK of the Receiver's Next TSN minus 1 were received MUST be

	 *     performed.

	 */

	sctp_outq_free(&asoc->outqueue);



	/* G2: Compute an appropriate value for the local endpoint's next TSN,

	 *     i.e., the next TSN assigned by the receiver of the SSN/TSN reset

	 *     chunk.  The value SHOULD be the highest TSN sent by the receiver

	 *     of the request plus 1.

	 */

	next_tsn = asoc->next_tsn;

	asoc->ctsn_ack_point = next_tsn - 1;

	asoc->adv_peer_ack_point = asoc->ctsn_ack_point;



	/* G5:  The next expected and outgoing SSNs MUST be reset to 0 for all

	 *      incoming and outgoing streams.

	 */

	for (i = 0; i < stream->outcnt; i++)

		stream->out[i].ssn = 0;

	for (i = 0; i < stream->incnt; i++)

		stream->in[i].ssn = 0;



	result = SCTP_STRRESET_PERFORMED;



	*evp = sctp_ulpevent_make_assoc_reset_event(asoc, 0, init_tsn,

						    next_tsn, GFP_ATOMIC);



out:

	return sctp_make_strreset_tsnresp(asoc, result, request_seq,

					  next_tsn, init_tsn);

}