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Commit 81054476 authored by Xin Long's avatar Xin Long Committed by David S. Miller
Browse files

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



This patch is to implement Receiver-Side Procedures for the Outgoing
SSN Reset Request Parameter described in rfc6525 section 5.2.2.

Note that some checks must be after request_seq check, as even those
checks fail, strreset_inseq still has to be increase by 1.

Signed-off-by: default avatarXin Long <lucien.xin@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 35ea82d6

include/net/sctp/sm.h

+6 −0
Original line number Diff line number Diff line
@@ -280,6 +280,12 @@ struct sctp_chunk *sctp_make_strreset_tsnresp( 
void sctp_chunk_assign_tsn(struct sctp_chunk *);

void sctp_chunk_assign_ssn(struct sctp_chunk *);



/* Prototypes for stream-processing functions.  */

struct sctp_chunk *sctp_process_strreset_outreq(

				struct sctp_association *asoc,

				union sctp_params param,

				struct sctp_ulpevent **evp);



/* Prototypes for statetable processing. */



int sctp_do_sm(struct net *net, sctp_event_t event_type, sctp_subtype_t subtype,

net/sctp/stream.c

+113 −0
Original line number Diff line number Diff line
@@ -294,3 +294,116 @@ int sctp_send_add_streams(struct sctp_association *asoc, 
out:

	return retval;

}



static sctp_paramhdr_t *sctp_chunk_lookup_strreset_param(

			struct sctp_association *asoc, __u32 resp_seq)

{

	struct sctp_chunk *chunk = asoc->strreset_chunk;

	struct sctp_reconf_chunk *hdr;

	union sctp_params param;



	if (ntohl(resp_seq) != asoc->strreset_outseq || !chunk)

		return NULL;



	hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;

	sctp_walk_params(param, hdr, params) {

		/* sctp_strreset_tsnreq is actually the basic structure

		 * of all stream reconf params, so it's safe to use it

		 * to access request_seq.

		 */

		struct sctp_strreset_tsnreq *req = param.v;



		if (req->request_seq == resp_seq)

			return param.v;

	}



	return NULL;

}



struct sctp_chunk *sctp_process_strreset_outreq(

				struct sctp_association *asoc,

				union sctp_params param,

				struct sctp_ulpevent **evp)

{

	struct sctp_strreset_outreq *outreq = param.v;

	struct sctp_stream *stream = asoc->stream;

	__u16 i, nums, flags = 0, *str_p = NULL;

	__u32 result = SCTP_STRRESET_DENIED;

	__u32 request_seq;



	request_seq = ntohl(outreq->request_seq);



	if (ntohl(outreq->send_reset_at_tsn) >

	    sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map)) {

		result = SCTP_STRRESET_IN_PROGRESS;

		goto out;

	}



	if (request_seq > asoc->strreset_inseq) {

		result = SCTP_STRRESET_ERR_BAD_SEQNO;

		goto out;

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

		asoc->strreset_inseq++;

	}



	/* Check strreset_enable after inseq inc, as sender cannot tell

	 * the peer doesn't enable strreset after receiving response with

	 * result denied, as well as to keep consistent with bsd.

	 */

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

		goto out;



	if (asoc->strreset_chunk) {

		sctp_paramhdr_t *param_hdr;

		struct sctp_transport *t;



		param_hdr = sctp_chunk_lookup_strreset_param(

					asoc, outreq->response_seq);

		if (!param_hdr || param_hdr->type !=

					SCTP_PARAM_RESET_IN_REQUEST) {

			/* same process with outstanding isn't 0 */

			result = SCTP_STRRESET_ERR_IN_PROGRESS;

			goto out;

		}



		asoc->strreset_outstanding--;

		asoc->strreset_outseq++;



		if (!asoc->strreset_outstanding) {

			t = asoc->strreset_chunk->transport;

			if (del_timer(&t->reconf_timer))

				sctp_transport_put(t);



			sctp_chunk_put(asoc->strreset_chunk);

			asoc->strreset_chunk = NULL;

		}



		flags = SCTP_STREAM_RESET_INCOMING_SSN;

	}



	nums = (ntohs(param.p->length) - sizeof(*outreq)) / 2;

	if (nums) {

		str_p = outreq->list_of_streams;

		for (i = 0; i < nums; i++) {

			if (ntohs(str_p[i]) >= stream->incnt) {

				result = SCTP_STRRESET_ERR_WRONG_SSN;

				goto out;

			}

		}



		for (i = 0; i < nums; i++)

			stream->in[ntohs(str_p[i])].ssn = 0;

	} else {

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

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

	}



	result = SCTP_STRRESET_PERFORMED;



	*evp = sctp_ulpevent_make_stream_reset_event(asoc,

		flags | SCTP_STREAM_RESET_OUTGOING_SSN, nums, str_p,

		GFP_ATOMIC);



out:

	return sctp_make_strreset_resp(asoc, result, request_seq);

}