inet/sctp/sctp_shutdown.c

	sctp_shutdown.c revision 77c67f2fb257d2c7dfa00389cd9cd7dd5f99a920
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sys/types.h>
#include <sys/systm.h>
#include <sys/stream.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/strsubr.h>
#include <sys/strsun.h>

#include <netinet/in.h>
#include <netinet/ip6.h>

#include <inet/common.h>
#include <inet/ip.h>
#include <inet/ip6.h>
#include <inet/mib2.h>
#include <inet/nd.h>
#include <inet/optcom.h>
#include <inet/sctp_ip.h>
#include "sctp_impl.h"

void
sctp_send_shutdown(sctp_t *sctp, int rexmit)
{
    mblk_t *smp;
    mblk_t *sendmp;
    sctp_chunk_hdr_t *sch;
    uint32_t *ctsn;
    sctp_faddr_t *fp;

    if (sctp->sctp_state != SCTPS_ESTABLISHED &&
        sctp->sctp_state != SCTPS_SHUTDOWN_PENDING &&
        sctp->sctp_state != SCTPS_SHUTDOWN_SENT) {
        return;
    }

    if (sctp->sctp_state == SCTPS_ESTABLISHED) {
        sctp->sctp_state = SCTPS_SHUTDOWN_PENDING;
        /*
         * We set an upper bound on how long we will
         * wait for a shutdown-ack from the peer. This
         * is to prevent the receiver from attempting
         * to create a half-closed state indefinately.
         * See archive from IETF TSVWG mailing list
         * for June 2001 for more information.
         * Since we will not be calculating RTTs after
         * sending the shutdown, we can overload out_time
         * to track how long we have waited.
         */
        sctp->sctp_out_time = lbolt64;
    }

    /*
     * If there is unsent (or unacked) data, wait for it to get ack'd
     */
    if (sctp->sctp_xmit_head != NULL || sctp->sctp_xmit_unsent != NULL) {
        return;
    }

    /* rotate faddrs if we are retransmitting */
    if (!rexmit) {
        fp = sctp->sctp_current;
    } else {
        fp = sctp_rotate_faddr(sctp, sctp->sctp_shutdown_faddr);
    }

    sctp->sctp_shutdown_faddr = fp;

    /* Link in a SACK if resending the shutdown */
    if (sctp->sctp_state > SCTPS_SHUTDOWN_PENDING &&
        (sendmp = sctp_make_sack(sctp, fp, NULL)) != NULL) {

        smp = allocb(sizeof (*sch) + sizeof (*ctsn), BPRI_MED);
        if (smp == NULL) {
            freemsg(sendmp);
            goto done;
        }
        linkb(sendmp, smp);

        sch = (sctp_chunk_hdr_t *)smp->b_rptr;
        smp->b_wptr = smp->b_rptr + sizeof (*sch) + sizeof (*ctsn);
    } else {
        sendmp = sctp_make_mp(sctp, fp,
            sizeof (*sch) + sizeof (*ctsn));
        if (sendmp == NULL) {
            SCTP_KSTAT(sctp_send_shutdown_failed);
            goto done;
        }
        sch = (sctp_chunk_hdr_t *)sendmp->b_wptr;
        sendmp->b_wptr += sizeof (*sch) + sizeof (*ctsn);

        /* shutdown w/o sack, update lastacked */
        sctp->sctp_lastacked = sctp->sctp_ftsn - 1;
    }

    sch->sch_id = CHUNK_SHUTDOWN;
    sch->sch_flags = 0;
    sch->sch_len = htons(sizeof (*sch) + sizeof (*ctsn));

    ctsn = (uint32_t *)(sch + 1);
    *ctsn = htonl(sctp->sctp_lastacked);

    /* Link the shutdown chunk in after the IP/SCTP header */

    sctp_set_iplen(sctp, sendmp);

    BUMP_LOCAL(sctp->sctp_obchunks);

    /* Send the shutdown and restart the timer */
    sctp_add_sendq(sctp, sendmp);

done:
    sctp->sctp_state = SCTPS_SHUTDOWN_SENT;
    SCTP_FADDR_TIMER_RESTART(sctp, sctp->sctp_current,
        sctp->sctp_current->rto);
}

int
sctp_shutdown_received(sctp_t *sctp, sctp_chunk_hdr_t *sch, boolean_t crwsd,
    boolean_t rexmit, sctp_faddr_t *fp)
{
    mblk_t *samp;
    sctp_chunk_hdr_t *sach;
    uint32_t *tsn;
    int trysend = 0;

    if (sctp->sctp_state != SCTPS_SHUTDOWN_ACK_SENT)
        sctp->sctp_state = SCTPS_SHUTDOWN_RECEIVED;

    /* Extract and process the TSN in the shutdown chunk */
    if (sch != NULL) {
        tsn = (uint32_t *)(sch + 1);
        trysend = sctp_cumack(sctp, ntohl(*tsn), &samp);
    }

    /* Don't allow sending new data */
    if (!SCTP_IS_DETACHED(sctp))
        sctp->sctp_ulp_disconnecting(sctp->sctp_ulpd);

    /*
     * If there is unsent or unacked data, try sending them out now.
     * The other side should acknowledge them.  After we have flushed
     * the transmit queue, we can complete the shutdown sequence.
     */
    if (sctp->sctp_xmit_head != NULL || sctp->sctp_xmit_unsent != NULL)
        return (1);

    if (fp == NULL) {
        /* rotate faddrs if we are retransmitting */
        if (!rexmit)
            fp = sctp->sctp_current;
        else
            fp = sctp_rotate_faddr(sctp, sctp->sctp_shutdown_faddr);
    }
    sctp->sctp_shutdown_faddr = fp;

    samp = sctp_make_mp(sctp, fp, sizeof (*sach));
    if (samp == NULL) {
        SCTP_KSTAT(sctp_send_shutdown_ack_failed);
        goto dotimer;
    }

    sach = (sctp_chunk_hdr_t *)samp->b_wptr;
    sach->sch_id = CHUNK_SHUTDOWN_ACK;
    sach->sch_flags = 0;
    sach->sch_len = htons(sizeof (*sach));

    samp->b_wptr += sizeof (*sach);

    /*
     * bundle a "cookie received while shutting down" error if
     * the caller asks for it.
     */
    if (crwsd) {
        mblk_t *errmp;

        errmp = sctp_make_err(sctp, SCTP_ERR_COOKIE_SHUT, NULL, 0);
        if (errmp != NULL) {
            linkb(samp, errmp);
            BUMP_LOCAL(sctp->sctp_obchunks);
        }
    }

    sctp_set_iplen(sctp, samp);

    BUMP_LOCAL(sctp->sctp_obchunks);

    sctp_add_sendq(sctp, samp);

dotimer:
    sctp->sctp_state = SCTPS_SHUTDOWN_ACK_SENT;
    SCTP_FADDR_TIMER_RESTART(sctp, sctp->sctp_current,
        sctp->sctp_current->rto);

    return (trysend);
}

void
sctp_shutdown_complete(sctp_t *sctp)
{
    mblk_t *scmp;
    sctp_chunk_hdr_t *scch;

    scmp = sctp_make_mp(sctp, NULL, sizeof (*scch));
    if (scmp == NULL) {
        /* XXX use timer approach */
        SCTP_KSTAT(sctp_send_shutdown_comp_failed);
        return;
    }

    scch = (sctp_chunk_hdr_t *)scmp->b_wptr;
    scch->sch_id = CHUNK_SHUTDOWN_COMPLETE;
    scch->sch_flags = 0;
    scch->sch_len = htons(sizeof (*scch));

    scmp->b_wptr += sizeof (*scch);

    sctp_set_iplen(sctp, scmp);

    BUMP_LOCAL(sctp->sctp_obchunks);

    sctp_add_sendq(sctp, scmp);
}

/*
 * Similar to sctp_shutdown_complete(), except that since this
 * is out-of-the-blue, we can't use an sctp's association information,
 * and instead must draw all necessary info from the incoming packet.
 */
void
sctp_ootb_shutdown_ack(sctp_t *gsctp, mblk_t *inmp, uint_t ip_hdr_len)
{
    boolean_t       isv4;
    ipha_t          *inip4h;
    ip6_t           *inip6h;
    sctp_hdr_t      *insctph;
    sctp_chunk_hdr_t    *scch;
    int         i;
    uint16_t        port;
    mblk_t          *mp1;

    isv4 = (IPH_HDR_VERSION(inmp->b_rptr) == IPV4_VERSION);

    /*
     * The gsctp should contain the minimal IP header.  So the
     * incoming mblk should be able to hold the new SCTP packet.
     */
    ASSERT(MBLKL(inmp) >= sizeof (*insctph) + sizeof (*scch) +
        (isv4 ? gsctp->sctp_ip_hdr_len : gsctp->sctp_ip_hdr6_len));

    /*
     * Check to see if we can reuse the incoming mblk.  There should
     * not be other reference and the db_base of the mblk should be
     * properly aligned.  Since this packet comes from below,
     * there should be enough header space to fill in what the lower
     * layers want to add.  And we will not stash anything there.
     */
    if (!IS_P2ALIGNED(DB_BASE(inmp), sizeof (ire_t *)) ||
        DB_REF(inmp) != 1) {
        mp1 = allocb(MBLKL(inmp) + sctp_wroff_xtra, BPRI_MED);
        if (mp1 == NULL) {
            freeb(inmp);
            return;
        }
        mp1->b_rptr += sctp_wroff_xtra;
        mp1->b_wptr = mp1->b_rptr + MBLKL(inmp);
        bcopy(inmp->b_rptr, mp1->b_rptr, MBLKL(inmp));
        freeb(inmp);
        inmp = mp1;
    }

    /*
     * We follow the logic in tcp_xmit_early_reset() in that we skip
     * reversing source route (i.e. relpace all IP options with EOL).
     */
    if (isv4) {
        ipaddr_t    v4addr;

        inip4h = (ipha_t *)inmp->b_rptr;
        for (i = IP_SIMPLE_HDR_LENGTH; i < (int)ip_hdr_len; i++)
            inmp->b_rptr[i] = IPOPT_EOL;
        /* Swap addresses */
        inip4h->ipha_length = htons(ip_hdr_len + sizeof (*insctph) +
            sizeof (*scch));
        v4addr = inip4h->ipha_src;
        inip4h->ipha_src = inip4h->ipha_dst;
        inip4h->ipha_dst = v4addr;
        inip4h->ipha_ident = 0;
        inip4h->ipha_ttl = (uchar_t)sctp_ipv4_ttl;
    } else {
        in6_addr_t  v6addr;

        inip6h = (ip6_t *)inmp->b_rptr;
        /* Remove any extension headers assuming partial overlay */
        if (ip_hdr_len > IPV6_HDR_LEN) {
            uint8_t *to;

            to = inmp->b_rptr + ip_hdr_len - IPV6_HDR_LEN;
            ovbcopy(inip6h, to, IPV6_HDR_LEN);
            inmp->b_rptr += ip_hdr_len - IPV6_HDR_LEN;
            ip_hdr_len = IPV6_HDR_LEN;
            inip6h = (ip6_t *)inmp->b_rptr;
            inip6h->ip6_nxt = IPPROTO_SCTP;
        }
        inip6h->ip6_plen = htons(ip_hdr_len + sizeof (*insctph) +
            sizeof (*scch) - IPV6_HDR_LEN);
        v6addr = inip6h->ip6_src;
        inip6h->ip6_src = inip6h->ip6_dst;
        inip6h->ip6_dst = v6addr;
        inip6h->ip6_hops = (uchar_t)sctp_ipv6_hoplimit;
    }
    insctph = (sctp_hdr_t *)(inmp->b_rptr + ip_hdr_len);

    /* Swap ports.  Verification tag is reused. */
    port = insctph->sh_sport;
    insctph->sh_sport = insctph->sh_dport;
    insctph->sh_dport = port;

    /* Lay in the shutdown complete chunk */
    scch = (sctp_chunk_hdr_t *)(insctph + 1);
    scch->sch_id = CHUNK_SHUTDOWN_COMPLETE;
    scch->sch_len = htons(sizeof (*scch));
    scch->sch_flags = 0;

    /* Set the T-bit */
    SCTP_SET_TBIT(scch);

    BUMP_LOCAL(gsctp->sctp_obchunks);
    /* Nothing to stash... */
    SCTP_STASH_IPINFO(inmp, (ire_t *)NULL);

    sctp_add_sendq(gsctp, inmp);
}