net/sctp/stream.c

/* SCTP kernel implementation
 * (C) Copyright IBM Corp. 2001, 2004
 * Copyright (c) 1999-2000 Cisco, Inc.
 * Copyright (c) 1999-2001 Motorola, Inc.
 * Copyright (c) 2001 Intel Corp.
 *
 * This file is part of the SCTP kernel implementation
 *
 * These functions manipulate sctp tsn mapping array.
 *
 * This SCTP implementation is free software;
 * you can redistribute it and/or modify it under the terms of
 * the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This SCTP implementation is distributed in the hope that it
 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
 *                 ************************
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU CC; see the file COPYING.  If not, see
 * <http://www.gnu.org/licenses/>.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <linux-sctp@vger.kernel.org>
 *
 * Written or modified by:
 *    Xin Long <lucien.xin@gmail.com>
 */

#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>

int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
		     gfp_t gfp)
{
	int i;

	/* Initial stream->out size may be very big, so free it and alloc
	 * a new one with new outcnt to save memory.
	 */
	kfree(stream->out);

	stream->out = kcalloc(outcnt, sizeof(*stream->out), gfp);
	if (!stream->out)
		return -ENOMEM;

	stream->outcnt = outcnt;
	for (i = 0; i < stream->outcnt; i++)
		stream->out[i].state = SCTP_STREAM_OPEN;

	if (!incnt)
		return 0;

	stream->in = kcalloc(incnt, sizeof(*stream->in), gfp);
	if (!stream->in) {
		kfree(stream->out);
		stream->out = NULL;
		return -ENOMEM;
	}

	stream->incnt = incnt;

	return 0;
}

void sctp_stream_free(struct sctp_stream *stream)
{
	kfree(stream->out);
	kfree(stream->in);
}

void sctp_stream_clear(struct sctp_stream *stream)
{
	int i;

	for (i = 0; i < stream->outcnt; i++)
		stream->out[i].ssn = 0;

	for (i = 0; i < stream->incnt; i++)
		stream->in[i].ssn = 0;
}

void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new)
{
	sctp_stream_free(stream);

	stream->out = new->out;
	stream->in  = new->in;
	stream->outcnt = new->outcnt;
	stream->incnt  = new->incnt;

	new->out = NULL;
	new->in  = NULL;
}

static int sctp_send_reconf(struct sctp_association *asoc,
			    struct sctp_chunk *chunk)
{
	struct net *net = sock_net(asoc->base.sk);
	int retval = 0;

	retval = sctp_primitive_RECONF(net, asoc, chunk);
	if (retval)
		sctp_chunk_free(chunk);

	return retval;
}

int sctp_send_reset_streams(struct sctp_association *asoc,
			    struct sctp_reset_streams *params)
{
	struct sctp_stream *stream = &asoc->stream;
	__u16 i, str_nums, *str_list;
	struct sctp_chunk *chunk;
	int retval = -EINVAL;
	bool out, in;

	if (!asoc->peer.reconf_capable ||
	    !(asoc->strreset_enable & SCTP_ENABLE_RESET_STREAM_REQ)) {
		retval = -ENOPROTOOPT;
		goto out;
	}

	if (asoc->strreset_outstanding) {
		retval = -EINPROGRESS;
		goto out;
	}

	out = params->srs_flags & SCTP_STREAM_RESET_OUTGOING;
	in  = params->srs_flags & SCTP_STREAM_RESET_INCOMING;
	if (!out && !in)
		goto out;

	str_nums = params->srs_number_streams;
	str_list = params->srs_stream_list;
	if (out && str_nums)
		for (i = 0; i < str_nums; i++)
			if (str_list[i] >= stream->outcnt)
				goto out;

	if (in && str_nums)
		for (i = 0; i < str_nums; i++)
			if (str_list[i] >= stream->incnt)
				goto out;

	for (i = 0; i < str_nums; i++)
		str_list[i] = htons(str_list[i]);

	chunk = sctp_make_strreset_req(asoc, str_nums, str_list, out, in);

	for (i = 0; i < str_nums; i++)
		str_list[i] = ntohs(str_list[i]);

	if (!chunk) {
		retval = -ENOMEM;
		goto out;
	}

	if (out) {
		if (str_nums)
			for (i = 0; i < str_nums; i++)
				stream->out[str_list[i]].state =
						       SCTP_STREAM_CLOSED;
		else
			for (i = 0; i < stream->outcnt; i++)
				stream->out[i].state = SCTP_STREAM_CLOSED;
	}

	asoc->strreset_chunk = chunk;
	sctp_chunk_hold(asoc->strreset_chunk);

	retval = sctp_send_reconf(asoc, chunk);
	if (retval) {
		sctp_chunk_put(asoc->strreset_chunk);
		asoc->strreset_chunk = NULL;
		if (!out)
			goto out;

		if (str_nums)
			for (i = 0; i < str_nums; i++)
				stream->out[str_list[i]].state =
						       SCTP_STREAM_OPEN;
		else
			for (i = 0; i < stream->outcnt; i++)
				stream->out[i].state = SCTP_STREAM_OPEN;

		goto out;
	}

	asoc->strreset_outstanding = out + in;

out:
	return retval;
}

int sctp_send_reset_assoc(struct sctp_association *asoc)
{
	struct sctp_stream *stream = &asoc->stream;
	struct sctp_chunk *chunk = NULL;
	int retval;
	__u16 i;

	if (!asoc->peer.reconf_capable ||
	    !(asoc->strreset_enable & SCTP_ENABLE_RESET_ASSOC_REQ))
		return -ENOPROTOOPT;

	if (asoc->strreset_outstanding)
		return -EINPROGRESS;

	chunk = sctp_make_strreset_tsnreq(asoc);
	if (!chunk)
		return -ENOMEM;

	/* Block further xmit of data until this request is completed */
	for (i = 0; i < stream->outcnt; i++)
		stream->out[i].state = SCTP_STREAM_CLOSED;

	asoc->strreset_chunk = chunk;
	sctp_chunk_hold(asoc->strreset_chunk);

	retval = sctp_send_reconf(asoc, chunk);
	if (retval) {
		sctp_chunk_put(asoc->strreset_chunk);
		asoc->strreset_chunk = NULL;

		for (i = 0; i < stream->outcnt; i++)
			stream->out[i].state = SCTP_STREAM_OPEN;

		return retval;
	}

	asoc->strreset_outstanding = 1;

	return 0;
}

int sctp_send_add_streams(struct sctp_association *asoc,
			  struct sctp_add_streams *params)
{
	struct sctp_stream *stream = &asoc->stream;
	struct sctp_chunk *chunk = NULL;
	int retval = -ENOMEM;
	__u32 outcnt, incnt;
	__u16 out, in;

	if (!asoc->peer.reconf_capable ||
	    !(asoc->strreset_enable & SCTP_ENABLE_CHANGE_ASSOC_REQ)) {
		retval = -ENOPROTOOPT;
		goto out;
	}

	if (asoc->strreset_outstanding) {
		retval = -EINPROGRESS;
		goto out;
	}

	out = params->sas_outstrms;
	in  = params->sas_instrms;
	outcnt = stream->outcnt + out;
	incnt = stream->incnt + in;
	if (outcnt > SCTP_MAX_STREAM || incnt > SCTP_MAX_STREAM ||
	    (!out && !in)) {
		retval = -EINVAL;
		goto out;
	}

	if (out) {
		struct sctp_stream_out *streamout;

		streamout = krealloc(stream->out, outcnt * sizeof(*streamout),
				     GFP_KERNEL);
		if (!streamout)
			goto out;

		memset(streamout + stream->outcnt, 0, out * sizeof(*streamout));
		stream->out = streamout;
	}

	chunk = sctp_make_strreset_addstrm(asoc, out, in);
	if (!chunk)
		goto out;

	asoc->strreset_chunk = chunk;
	sctp_chunk_hold(asoc->strreset_chunk);

	retval = sctp_send_reconf(asoc, chunk);
	if (retval) {
		sctp_chunk_put(asoc->strreset_chunk);
		asoc->strreset_chunk = NULL;
		goto out;
	}

	stream->incnt = incnt;
	stream->outcnt = outcnt;

	asoc->strreset_outstanding = !!out + !!in;

out:
	return retval;
}

static sctp_paramhdr_t *sctp_chunk_lookup_strreset_param(
			struct sctp_association *asoc, __u32 resp_seq,
			__be16 type)
{
	struct sctp_chunk *chunk = asoc->strreset_chunk;
	struct sctp_reconf_chunk *hdr;
	union sctp_params param;

	if (!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 ((!resp_seq || req->request_seq == resp_seq) &&
		    (!type || type == req->param_hdr.type))
			return param.v;
	}

	return NULL;
}

static void sctp_update_strreset_result(struct sctp_association *asoc,
					__u32 result)
{
	asoc->strreset_result[1] = asoc->strreset_result[0];
	asoc->strreset_result[0] = result;
}

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 err;
	}

	if (TSN_lt(asoc->strreset_inseq, request_seq) ||
	    TSN_lt(request_seq, asoc->strreset_inseq - 2)) {
		result = SCTP_STRRESET_ERR_BAD_SEQNO;
		goto err;
	} else if (TSN_lt(request_seq, asoc->strreset_inseq)) {
		i = asoc->strreset_inseq - request_seq - 1;
		result = asoc->strreset_result[i];
		goto err;
	}
	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) {
		if (!sctp_chunk_lookup_strreset_param(
				asoc, outreq->response_seq,
				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) {
			struct sctp_transport *t;

			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:
	sctp_update_strreset_result(asoc, result);
err:
	return sctp_make_strreset_resp(asoc, result, request_seq);
}

struct sctp_chunk *sctp_process_strreset_inreq(
				struct sctp_association *asoc,
				union sctp_params param,
				struct sctp_ulpevent **evp)
{
	struct sctp_strreset_inreq *inreq = param.v;
	struct sctp_stream *stream = &asoc->stream;
	__u32 result = SCTP_STRRESET_DENIED;
	struct sctp_chunk *chunk = NULL;
	__u16 i, nums, *str_p;
	__u32 request_seq;

	request_seq = ntohl(inreq->request_seq);
	if (TSN_lt(asoc->strreset_inseq, request_seq) ||
	    TSN_lt(request_seq, asoc->strreset_inseq - 2)) {
		result = SCTP_STRRESET_ERR_BAD_SEQNO;
		goto err;
	} else if (TSN_lt(request_seq, asoc->strreset_inseq)) {
		i = asoc->strreset_inseq - request_seq - 1;
		result = asoc->strreset_result[i];
		if (result == SCTP_STRRESET_PERFORMED)
			return NULL;
		goto err;
	}
	asoc->strreset_inseq++;

	if (!(asoc->strreset_enable & SCTP_ENABLE_RESET_STREAM_REQ))
		goto out;

	if (asoc->strreset_outstanding) {
		result = SCTP_STRRESET_ERR_IN_PROGRESS;
		goto out;
	}

	nums = (ntohs(param.p->length) - sizeof(*inreq)) / 2;
	str_p = inreq->list_of_streams;
	for (i = 0; i < nums; i++) {
		if (ntohs(str_p[i]) >= stream->outcnt) {
			result = SCTP_STRRESET_ERR_WRONG_SSN;
			goto out;
		}
	}

	chunk = sctp_make_strreset_req(asoc, nums, str_p, 1, 0);
	if (!chunk)
		goto out;

	if (nums)
		for (i = 0; i < nums; i++)
			stream->out[ntohs(str_p[i])].state =
					       SCTP_STREAM_CLOSED;
	else
		for (i = 0; i < stream->outcnt; i++)
			stream->out[i].state = SCTP_STREAM_CLOSED;

	asoc->strreset_chunk = chunk;
	asoc->strreset_outstanding = 1;
	sctp_chunk_hold(asoc->strreset_chunk);

	result = SCTP_STRRESET_PERFORMED;

	*evp = sctp_ulpevent_make_stream_reset_event(asoc,
		SCTP_STREAM_RESET_INCOMING_SSN, nums, str_p, GFP_ATOMIC);

out:
	sctp_update_strreset_result(asoc, result);
err:
	if (!chunk)
		chunk =  sctp_make_strreset_resp(asoc, result, request_seq);

	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 (TSN_lt(asoc->strreset_inseq, request_seq) ||
	    TSN_lt(request_seq, asoc->strreset_inseq - 2)) {
		result = SCTP_STRRESET_ERR_BAD_SEQNO;
		goto err;
	} else if (TSN_lt(request_seq, asoc->strreset_inseq)) {
		i = asoc->strreset_inseq - request_seq - 1;
		result = asoc->strreset_result[i];
		if (result == SCTP_STRRESET_PERFORMED) {
			next_tsn = asoc->next_tsn;
			init_tsn =
				sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + 1;
		}
		goto err;
	}
	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:
	sctp_update_strreset_result(asoc, result);
err:
	return sctp_make_strreset_tsnresp(asoc, result, request_seq,
					  next_tsn, init_tsn);
}

struct sctp_chunk *sctp_process_strreset_addstrm_out(
				struct sctp_association *asoc,
				union sctp_params param,
				struct sctp_ulpevent **evp)
{
	struct sctp_strreset_addstrm *addstrm = param.v;
	struct sctp_stream *stream = &asoc->stream;
	__u32 result = SCTP_STRRESET_DENIED;
	struct sctp_stream_in *streamin;
	__u32 request_seq, incnt;
	__u16 in, i;

	request_seq = ntohl(addstrm->request_seq);
	if (TSN_lt(asoc->strreset_inseq, request_seq) ||
	    TSN_lt(request_seq, asoc->strreset_inseq - 2)) {
		result = SCTP_STRRESET_ERR_BAD_SEQNO;
		goto err;
	} else if (TSN_lt(request_seq, asoc->strreset_inseq)) {
		i = asoc->strreset_inseq - request_seq - 1;
		result = asoc->strreset_result[i];
		goto err;
	}
	asoc->strreset_inseq++;

	if (!(asoc->strreset_enable & SCTP_ENABLE_CHANGE_ASSOC_REQ))
		goto out;

	if (asoc->strreset_chunk) {
		if (!sctp_chunk_lookup_strreset_param(
			asoc, 0, SCTP_PARAM_RESET_ADD_IN_STREAMS)) {
			/* 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) {
			struct sctp_transport *t;

			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;
		}
	}

	in = ntohs(addstrm->number_of_streams);
	incnt = stream->incnt + in;
	if (!in || incnt > SCTP_MAX_STREAM)
		goto out;

	streamin = krealloc(stream->in, incnt * sizeof(*streamin),
			    GFP_ATOMIC);
	if (!streamin)
		goto out;

	memset(streamin + stream->incnt, 0, in * sizeof(*streamin));
	stream->in = streamin;
	stream->incnt = incnt;

	result = SCTP_STRRESET_PERFORMED;

	*evp = sctp_ulpevent_make_stream_change_event(asoc,
		0, ntohs(addstrm->number_of_streams), 0, GFP_ATOMIC);

out:
	sctp_update_strreset_result(asoc, result);
err:
	return sctp_make_strreset_resp(asoc, result, request_seq);
}

struct sctp_chunk *sctp_process_strreset_addstrm_in(
				struct sctp_association *asoc,
				union sctp_params param,
				struct sctp_ulpevent **evp)
{
	struct sctp_strreset_addstrm *addstrm = param.v;
	struct sctp_stream *stream = &asoc->stream;
	__u32 result = SCTP_STRRESET_DENIED;
	struct sctp_stream_out *streamout;
	struct sctp_chunk *chunk = NULL;
	__u32 request_seq, outcnt;
	__u16 out, i;

	request_seq = ntohl(addstrm->request_seq);
	if (TSN_lt(asoc->strreset_inseq, request_seq) ||
	    TSN_lt(request_seq, asoc->strreset_inseq - 2)) {
		result = SCTP_STRRESET_ERR_BAD_SEQNO;
		goto err;
	} else if (TSN_lt(request_seq, asoc->strreset_inseq)) {
		i = asoc->strreset_inseq - request_seq - 1;
		result = asoc->strreset_result[i];
		if (result == SCTP_STRRESET_PERFORMED)
			return NULL;
		goto err;
	}
	asoc->strreset_inseq++;

	if (!(asoc->strreset_enable & SCTP_ENABLE_CHANGE_ASSOC_REQ))
		goto out;

	if (asoc->strreset_outstanding) {
		result = SCTP_STRRESET_ERR_IN_PROGRESS;
		goto out;
	}

	out = ntohs(addstrm->number_of_streams);
	outcnt = stream->outcnt + out;
	if (!out || outcnt > SCTP_MAX_STREAM)
		goto out;

	streamout = krealloc(stream->out, outcnt * sizeof(*streamout),
			     GFP_ATOMIC);
	if (!streamout)
		goto out;

	memset(streamout + stream->outcnt, 0, out * sizeof(*streamout));
	stream->out = streamout;

	chunk = sctp_make_strreset_addstrm(asoc, out, 0);
	if (!chunk)
		goto out;

	asoc->strreset_chunk = chunk;
	asoc->strreset_outstanding = 1;
	sctp_chunk_hold(asoc->strreset_chunk);

	stream->outcnt = outcnt;

	result = SCTP_STRRESET_PERFORMED;

	*evp = sctp_ulpevent_make_stream_change_event(asoc,
		0, 0, ntohs(addstrm->number_of_streams), GFP_ATOMIC);

out:
	sctp_update_strreset_result(asoc, result);
err:
	if (!chunk)
		chunk = sctp_make_strreset_resp(asoc, result, request_seq);

	return chunk;
}

struct sctp_chunk *sctp_process_strreset_resp(
				struct sctp_association *asoc,
				union sctp_params param,
				struct sctp_ulpevent **evp)
{
	struct sctp_stream *stream = &asoc->stream;
	struct sctp_strreset_resp *resp = param.v;
	struct sctp_transport *t;
	__u16 i, nums, flags = 0;
	sctp_paramhdr_t *req;
	__u32 result;

	req = sctp_chunk_lookup_strreset_param(asoc, resp->response_seq, 0);
	if (!req)
		return NULL;

	result = ntohl(resp->result);
	if (result != SCTP_STRRESET_PERFORMED) {
		/* if in progress, do nothing but retransmit */
		if (result == SCTP_STRRESET_IN_PROGRESS)
			return NULL;
		else if (result == SCTP_STRRESET_DENIED)
			flags = SCTP_STREAM_RESET_DENIED;
		else
			flags = SCTP_STREAM_RESET_FAILED;
	}

	if (req->type == SCTP_PARAM_RESET_OUT_REQUEST) {
		struct sctp_strreset_outreq *outreq;
		__u16 *str_p;

		outreq = (struct sctp_strreset_outreq *)req;
		str_p = outreq->list_of_streams;
		nums = (ntohs(outreq->param_hdr.length) - sizeof(*outreq)) / 2;

		if (result == SCTP_STRRESET_PERFORMED) {
			if (nums) {
				for (i = 0; i < nums; i++)
					stream->out[ntohs(str_p[i])].ssn = 0;
			} else {
				for (i = 0; i < stream->outcnt; i++)
					stream->out[i].ssn = 0;
			}

			flags = SCTP_STREAM_RESET_OUTGOING_SSN;
		}

		for (i = 0; i < stream->outcnt; i++)
			stream->out[i].state = SCTP_STREAM_OPEN;

		*evp = sctp_ulpevent_make_stream_reset_event(asoc, flags,
			nums, str_p, GFP_ATOMIC);
	} else if (req->type == SCTP_PARAM_RESET_IN_REQUEST) {
		struct sctp_strreset_inreq *inreq;
		__u16 *str_p;

		/* if the result is performed, it's impossible for inreq */
		if (result == SCTP_STRRESET_PERFORMED)
			return NULL;

		inreq = (struct sctp_strreset_inreq *)req;
		str_p = inreq->list_of_streams;
		nums = (ntohs(inreq->param_hdr.length) - sizeof(*inreq)) / 2;

		*evp = sctp_ulpevent_make_stream_reset_event(asoc, flags,
			nums, str_p, GFP_ATOMIC);
	} else if (req->type == SCTP_PARAM_RESET_TSN_REQUEST) {
		struct sctp_strreset_resptsn *resptsn;
		__u32 stsn, rtsn;

		/* check for resptsn, as sctp_verify_reconf didn't do it*/
		if (ntohs(param.p->length) != sizeof(*resptsn))
			return NULL;

		resptsn = (struct sctp_strreset_resptsn *)resp;
		stsn = ntohl(resptsn->senders_next_tsn);
		rtsn = ntohl(resptsn->receivers_next_tsn);

		if (result == SCTP_STRRESET_PERFORMED) {
			__u32 mtsn = sctp_tsnmap_get_max_tsn_seen(
						&asoc->peer.tsn_map);

			sctp_ulpq_reasm_flushtsn(&asoc->ulpq, mtsn);
			sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);

			sctp_tsnmap_init(&asoc->peer.tsn_map,
					 SCTP_TSN_MAP_INITIAL,
					 stsn, GFP_ATOMIC);

			sctp_outq_free(&asoc->outqueue);

			asoc->next_tsn = rtsn;
			asoc->ctsn_ack_point = asoc->next_tsn - 1;
			asoc->adv_peer_ack_point = asoc->ctsn_ack_point;

			for (i = 0; i < stream->outcnt; i++)
				stream->out[i].ssn = 0;
			for (i = 0; i < stream->incnt; i++)
				stream->in[i].ssn = 0;
		}

		for (i = 0; i < stream->outcnt; i++)
			stream->out[i].state = SCTP_STREAM_OPEN;

		*evp = sctp_ulpevent_make_assoc_reset_event(asoc, flags,
			stsn, rtsn, GFP_ATOMIC);
	} else if (req->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) {
		struct sctp_strreset_addstrm *addstrm;
		__u16 number;

		addstrm = (struct sctp_strreset_addstrm *)req;
		nums = ntohs(addstrm->number_of_streams);
		number = stream->outcnt - nums;

		if (result == SCTP_STRRESET_PERFORMED)
			for (i = number; i < stream->outcnt; i++)
				stream->out[i].state = SCTP_STREAM_OPEN;
		else
			stream->outcnt = number;

		*evp = sctp_ulpevent_make_stream_change_event(asoc, flags,
			0, nums, GFP_ATOMIC);
	} else if (req->type == SCTP_PARAM_RESET_ADD_IN_STREAMS) {
		struct sctp_strreset_addstrm *addstrm;

		/* if the result is performed, it's impossible for addstrm in
		 * request.
		 */
		if (result == SCTP_STRRESET_PERFORMED)
			return NULL;

		addstrm = (struct sctp_strreset_addstrm *)req;
		nums = ntohs(addstrm->number_of_streams);

		*evp = sctp_ulpevent_make_stream_change_event(asoc, flags,
			nums, 0, GFP_ATOMIC);
	}

	asoc->strreset_outstanding--;
	asoc->strreset_outseq++;

	/* remove everything for this reconf request */
	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;
	}

	return NULL;
}