/* 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
 *
 * This file contains sctp stream maniuplation primitives and helpers.
 *
 * 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 <linux/list.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>
#include <net/sctp/stream_sched.h>

static void sctp_stream_shrink_out(struct sctp_stream *stream, __u16 outcnt)
{
        struct sctp_association *asoc;
        struct sctp_chunk *ch, *temp;
        struct sctp_outq *outq;

        asoc = container_of(stream, struct sctp_association, stream);
        outq = &asoc->outqueue;

        list_for_each_entry_safe(ch, temp, &outq->out_chunk_list, list) {
                __u16 sid = sctp_chunk_stream_no(ch);

                if (sid < outcnt)
                        continue;

                sctp_sched_dequeue_common(outq, ch);
                /* No need to call dequeue_done here because
                 * the chunks are not scheduled by now.
                 */

                /* Mark as failed send. */
                sctp_chunk_fail(ch, (__force __u32)SCTP_ERROR_INV_STRM);
                if (asoc->peer.prsctp_capable &&
                    SCTP_PR_PRIO_ENABLED(ch->sinfo.sinfo_flags))
                        asoc->sent_cnt_removable--;

                sctp_chunk_free(ch);
        }
}

/* Migrates chunks from stream queues to new stream queues if needed,
 * but not across associations. Also, removes those chunks to streams
 * higher than the new max.
 */
static void sctp_stream_outq_migrate(struct sctp_stream *stream,
                                     struct sctp_stream *new, __u16 outcnt)
{
        int i;

        if (stream->outcnt > outcnt)
                sctp_stream_shrink_out(stream, outcnt);

        if (new) {
                /* Here we actually move the old ext stuff into the new
                 * buffer, because we want to keep it. Then
                 * sctp_stream_update will swap ->out pointers.
                 */
                for (i = 0; i < outcnt; i++) {
                        kfree(new->out[i].ext);
                        new->out[i].ext = stream->out[i].ext;
                        stream->out[i].ext = NULL;
                }
        }

        for (i = outcnt; i < stream->outcnt; i++) {
                kfree(stream->out[i].ext);
                stream->out[i].ext = NULL;
        }
}

static int sctp_stream_alloc_out(struct sctp_stream *stream, __u16 outcnt,
                                 gfp_t gfp)
{
        struct sctp_stream_out *out;

        out = kmalloc_array(outcnt, sizeof(*out), gfp);
        if (!out)
                return -ENOMEM;

        if (stream->out) {
                memcpy(out, stream->out, min(outcnt, stream->outcnt) *
                                         sizeof(*out));
                if (stream->out_curr)
                        stream->out_curr = out +
                                           (stream->out_curr - stream->out);
                kfree(stream->out);
        }

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

        stream->out = out;

        return 0;
}

static int sctp_stream_alloc_in(struct sctp_stream *stream, __u16 incnt,
                                gfp_t gfp)
{
        struct sctp_stream_in *in;

        in = kmalloc_array(incnt, sizeof(*stream->in), gfp);

        if (!in)
                return -ENOMEM;

        if (stream->in) {
                memcpy(in, stream->in, min(incnt, stream->incnt) *
                                       sizeof(*in));
                kfree(stream->in);
        }

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

        stream->in = in;

        return 0;
}

int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
                     gfp_t gfp)
{
        struct sctp_sched_ops *sched = sctp_sched_ops_from_stream(stream);
        int i, ret = 0;

        gfp |= __GFP_NOWARN;

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

        /* Filter out chunks queued on streams that won't exist anymore */
        sched->unsched_all(stream);
        sctp_stream_outq_migrate(stream, NULL, outcnt);
        sched->sched_all(stream);

        ret = sctp_stream_alloc_out(stream, outcnt, gfp);
        if (ret)
                goto out;

        stream->outcnt = outcnt;
        for (i = 0; i < stream->outcnt; i++)
                SCTP_SO(stream, i)->state = SCTP_STREAM_OPEN;

in:
        sctp_stream_interleave_init(stream);
        if (!incnt)
                goto out;

        ret = sctp_stream_alloc_in(stream, incnt, gfp);
        if (ret) {
                sched->free(stream);
                kfree(stream->out);
                stream->out = NULL;
                stream->outcnt = 0;
                goto out;
        }

        stream->incnt = incnt;

out:
        return ret;
}

int sctp_stream_init_ext(struct sctp_stream *stream, __u16 sid)
{
        struct sctp_stream_out_ext *soute;
        int ret;

        soute = kzalloc(sizeof(*soute), GFP_KERNEL);
        if (!soute)
                return -ENOMEM;
        SCTP_SO(stream, sid)->ext = soute;

        ret = sctp_sched_init_sid(stream, sid, GFP_KERNEL);
        if (ret) {
                kfree(SCTP_SO(stream, sid)->ext);
                SCTP_SO(stream, sid)->ext = NULL;
        }

        return ret;
}

void sctp_stream_free(struct sctp_stream *stream)
{
        struct sctp_sched_ops *sched = sctp_sched_ops_from_stream(stream);
        int i;

        sched->free(stream);
        for (i = 0; i < stream->outcnt; i++)
                kfree(SCTP_SO(stream, i)->ext);
        kfree(stream->out);
        kfree(stream->in);
}

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

        for (i = 0; i < stream->outcnt; i++) {
                SCTP_SO(stream, i)->mid = 0;
                SCTP_SO(stream, i)->mid_uo = 0;
        }

        for (i = 0; i < stream->incnt; i++)
                SCTP_SI(stream, i)->mid = 0;
}

void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new)
{
        struct sctp_sched_ops *sched = sctp_sched_ops_from_stream(stream);

        sched->unsched_all(stream);
        sctp_stream_outq_migrate(stream, new, new->outcnt);
        sctp_stream_free(stream);

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

        sched->sched_all(stream);

        new->out = NULL;
        new->in  = NULL;
        new->outcnt = 0;
        new->incnt  = 0;
}

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;
}

static bool sctp_stream_outq_is_empty(struct sctp_stream *stream,
                                      __u16 str_nums, __be16 *str_list)
{
        struct sctp_association *asoc;
        __u16 i;

        asoc = container_of(stream, struct sctp_association, stream);
        if (!asoc->outqueue.out_qlen)
                return true;

        if (!str_nums)
                return false;

        for (i = 0; i < str_nums; i++) {
                __u16 sid = ntohs(str_list[i]);

                if (SCTP_SO(stream, sid)->ext &&
                    !list_empty(&SCTP_SO(stream, sid)->ext->outq))
                        return false;
        }

        return true;
}

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;
        __be16 *nstr_list;
        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 (str_nums) {
                int param_len = 0;

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

                        param_len = str_nums * sizeof(__u16) +
                                    sizeof(struct sctp_strreset_outreq);
                }

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

                        param_len += str_nums * sizeof(__u16) +
                                     sizeof(struct sctp_strreset_inreq);
                }

                if (param_len > SCTP_MAX_CHUNK_LEN -
                                sizeof(struct sctp_reconf_chunk))
                        goto out;
        }

        nstr_list = kcalloc(str_nums, sizeof(__be16), GFP_KERNEL);
        if (!nstr_list) {
                retval = -ENOMEM;
                goto out;
        }

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

        if (out && !sctp_stream_outq_is_empty(stream, str_nums, nstr_list)) {
                kfree(nstr_list);
                retval = -EAGAIN;
                goto out;
        }

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

        kfree(nstr_list);

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

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

        if (!sctp_outq_is_empty(&asoc->outqueue))
                return -EAGAIN;

        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++)
                SCTP_SO(stream, 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++)
                        SCTP_SO(stream, 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;
        __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) {
                retval = sctp_stream_alloc_out(stream, outcnt, GFP_KERNEL);
                if (retval)
                        goto out;
        }

        chunk = sctp_make_strreset_addstrm(asoc, out, in);
        if (!chunk) {
                retval = -ENOMEM;
                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->outcnt = outcnt;

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

out:
        return retval;
}

static struct sctp_paramhdr *sctp_chunk_lookup_strreset_param(
                        struct sctp_association *asoc, __be32 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;
        __u32 result = SCTP_STRRESET_DENIED;
        __be16 *str_p = NULL;
        __u32 request_seq;
        __u16 i, nums;

        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;

        nums = (ntohs(param.p->length) - sizeof(*outreq)) / sizeof(__u16);
        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;
                }
        }

        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;
                }
        }

        if (nums)
                for (i = 0; i < nums; i++)
                        SCTP_SI(stream, ntohs(str_p[i]))->mid = 0;
        else
                for (i = 0; i < stream->incnt; i++)
                        SCTP_SI(stream, i)->mid = 0;

        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:
        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;
        __u32 request_seq;
        __u16 i, nums;
        __be16 *str_p;

        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)) / sizeof(__u16);
        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;
                }
        }

        if (!sctp_stream_outq_is_empty(stream, nums, str_p)) {
                result = SCTP_STRRESET_IN_PROGRESS;
                asoc->strreset_inseq--;
                goto err;
        }

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

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

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

        result = SCTP_STRRESET_PERFORMED;

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->ctsn_ack_point + 1;
                        init_tsn =
                                sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + 1;
                }
                goto err;
        }

        if (!sctp_outq_is_empty(&asoc->outqueue)) {
                result = SCTP_STRRESET_IN_PROGRESS;
                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;
        }

        /* 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.
         */
        max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
        asoc->stream.si->report_ftsn(&asoc->ulpq, max_tsn_seen);

        /* 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);

        /* 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.
         */
        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++) {
                SCTP_SO(stream, i)->mid = 0;
                SCTP_SO(stream, i)->mid_uo = 0;
        }
        for (i = 0; i < stream->incnt; i++)
                SCTP_SI(stream, i)->mid = 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;
        __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;

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

        if (sctp_stream_alloc_in(stream, incnt, GFP_ATOMIC))
                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;
                }
        }

        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_chunk *chunk = NULL;
        __u32 request_seq, outcnt;
        __u16 out, i;
        int ret;

        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;

        ret = sctp_stream_alloc_out(stream, outcnt, GFP_ATOMIC);
        if (ret)
                goto out;

        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;

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;
        struct sctp_paramhdr *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;
                __be16 *str_p;

                outreq = (struct sctp_strreset_outreq *)req;
                str_p = outreq->list_of_streams;
                nums = (ntohs(outreq->param_hdr.length) - sizeof(*outreq)) /
                       sizeof(__u16);

                if (result == SCTP_STRRESET_PERFORMED) {
                        struct sctp_stream_out *sout;
                        if (nums) {
                                for (i = 0; i < nums; i++) {
                                        sout = SCTP_SO(stream, ntohs(str_p[i]));
                                        sout->mid = 0;
                                        sout->mid_uo = 0;
                                }
                        } else {
                                for (i = 0; i < stream->outcnt; i++) {
                                        sout = SCTP_SO(stream, i);
                                        sout->mid = 0;
                                        sout->mid_uo = 0;

                                }
                        }
                }

                flags |= SCTP_STREAM_RESET_OUTGOING_SSN;

                for (i = 0; i < stream->outcnt; i++)
                        SCTP_SO(stream, 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;
                __be16 *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)) /
                       sizeof(__u16);

                flags |= SCTP_STREAM_RESET_INCOMING_SSN;

                *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);
                        LIST_HEAD(temp);

                        asoc->stream.si->report_ftsn(&asoc->ulpq, mtsn);

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

                        /* Clean up sacked and abandoned queues only. As the
                         * out_chunk_list may not be empty, splice it to temp,
                         * then get it back after sctp_outq_free is done.
                         */
                        list_splice_init(&asoc->outqueue.out_chunk_list, &temp);
                        sctp_outq_free(&asoc->outqueue);
                        list_splice_init(&temp, &asoc->outqueue.out_chunk_list);

                        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++) {
                                SCTP_SO(stream, i)->mid = 0;
                                SCTP_SO(stream, i)->mid_uo = 0;
                        }
                        for (i = 0; i < stream->incnt; i++)
                                SCTP_SI(stream, i)->mid = 0;
                }

                for (i = 0; i < stream->outcnt; i++)
                        SCTP_SO(stream, 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++)
                                SCTP_SO(stream, i)->state = SCTP_STREAM_OPEN;
                } else {
                        sctp_stream_shrink_out(stream, number);
                        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;
}