inet/sctp/sctp_shutdown.c

	sctp_shutdown.c revision d3d50737e566cade9a08d73d2af95105ac7cd960
/*
 * 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 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#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/ipsec_impl.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 <inet/ipclassifier.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;
    sctp_stack_t    *sctps = sctp->sctp_sctps;

    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 = ddi_get_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(sctps, 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 */

    BUMP_LOCAL(sctp->sctp_obchunks);

    /* Send the shutdown and restart the timer */
    sctp_set_iplen(sctp, sendmp, fp->ixa);
    (void) conn_ip_output(sendmp, fp->ixa);
    BUMP_LOCAL(sctp->sctp_opkts);

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;
    sctp_stack_t    *sctps = sctp->sctp_sctps;

    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_discon_done) {
        sctp->sctp_ulp_opctl(sctp->sctp_ulpd, SOCK_OPCTL_SHUT_SEND, 0);
        sctp->sctp_ulp_discon_done = B_TRUE;
    }

    /*
     * 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(sctps, 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);
        }
    }

    BUMP_LOCAL(sctp->sctp_obchunks);

    sctp_set_iplen(sctp, samp, fp->ixa);
    (void) conn_ip_output(samp, fp->ixa);
    BUMP_LOCAL(sctp->sctp_opkts);

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;
    sctp_stack_t    *sctps = sctp->sctp_sctps;

    scmp = sctp_make_mp(sctp, sctp->sctp_current, sizeof (*scch));
    if (scmp == NULL) {
        /* XXX use timer approach */
        SCTP_KSTAT(sctps, 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);

    BUMP_LOCAL(sctp->sctp_obchunks);

    sctp_set_iplen(sctp, scmp, sctp->sctp_current->ixa);
    (void) conn_ip_output(scmp, sctp->sctp_current->ixa);
    BUMP_LOCAL(sctp->sctp_opkts);
}

/*
 * 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(mblk_t *mp, uint_t ip_hdr_len, ip_recv_attr_t *ira,
    ip_stack_t *ipst)
{
    boolean_t       isv4;
    ipha_t          *ipha = NULL;
    ip6_t           *ip6h = NULL;
    sctp_hdr_t      *insctph;
    sctp_chunk_hdr_t    *scch;
    int         i;
    uint16_t        port;
    mblk_t          *mp1;
    netstack_t      *ns = ipst->ips_netstack;
    sctp_stack_t        *sctps = ns->netstack_sctp;
    ip_xmit_attr_t      ixas;

    bzero(&ixas, sizeof (ixas));

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

    ASSERT(MBLKL(mp) >= sizeof (*insctph) + sizeof (*scch) +
        (isv4 ? sizeof (ipha_t) : sizeof (ip6_t)));

    /*
     * Check to see if we can reuse the incoming mblk.  There should
     * not be other reference. Since this packet comes from below,
     * there should be enough header space to fill in what the lower
     * layers want to add.
     */
    if (DB_REF(mp) != 1) {
        mp1 = allocb(MBLKL(mp) + sctps->sctps_wroff_xtra, BPRI_MED);
        if (mp1 == NULL) {
            freeb(mp);
            return;
        }
        mp1->b_rptr += sctps->sctps_wroff_xtra;
        mp1->b_wptr = mp1->b_rptr + MBLKL(mp);
        bcopy(mp->b_rptr, mp1->b_rptr, MBLKL(mp));
        freeb(mp);
        mp = mp1;
    } else {
        DB_CKSUMFLAGS(mp) = 0;
    }

    ixas.ixa_pktlen = ip_hdr_len + sizeof (*insctph) + sizeof (*scch);
    ixas.ixa_ip_hdr_length = ip_hdr_len;
    /*
     * We follow the logic in tcp_xmit_early_reset() in that we skip
     * reversing source route (i.e. replace all IP options with EOL).
     */
    if (isv4) {
        ipaddr_t    v4addr;

        ipha = (ipha_t *)mp->b_rptr;
        for (i = IP_SIMPLE_HDR_LENGTH; i < (int)ip_hdr_len; i++)
            mp->b_rptr[i] = IPOPT_EOL;
        /* Swap addresses */
        ipha->ipha_length = htons(ixas.ixa_pktlen);
        v4addr = ipha->ipha_src;
        ipha->ipha_src = ipha->ipha_dst;
        ipha->ipha_dst = v4addr;
        ipha->ipha_ident = 0;
        ipha->ipha_ttl = (uchar_t)sctps->sctps_ipv4_ttl;

        ixas.ixa_flags = IXAF_BASIC_SIMPLE_V4;
    } else {
        in6_addr_t  v6addr;

        ip6h = (ip6_t *)mp->b_rptr;
        /* Remove any extension headers assuming partial overlay */
        if (ip_hdr_len > IPV6_HDR_LEN) {
            uint8_t *to;

            to = mp->b_rptr + ip_hdr_len - IPV6_HDR_LEN;
            ovbcopy(ip6h, to, IPV6_HDR_LEN);
            mp->b_rptr += ip_hdr_len - IPV6_HDR_LEN;
            ip_hdr_len = IPV6_HDR_LEN;
            ip6h = (ip6_t *)mp->b_rptr;
            ip6h->ip6_nxt = IPPROTO_SCTP;
        }
        ip6h->ip6_plen = htons(ixas.ixa_pktlen - IPV6_HDR_LEN);
        v6addr = ip6h->ip6_src;
        ip6h->ip6_src = ip6h->ip6_dst;
        ip6h->ip6_dst = v6addr;
        ip6h->ip6_hops = (uchar_t)sctps->sctps_ipv6_hoplimit;

        ixas.ixa_flags = IXAF_BASIC_SIMPLE_V6;
        if (IN6_IS_ADDR_LINKSCOPE(&ip6h->ip6_dst)) {
            ixas.ixa_flags |= IXAF_SCOPEID_SET;
            ixas.ixa_scopeid = ira->ira_ruifindex;
        }
    }

    insctph = (sctp_hdr_t *)(mp->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);

    ixas.ixa_protocol = IPPROTO_SCTP;
    ixas.ixa_zoneid = ira->ira_zoneid;
    ixas.ixa_ipst = ipst;
    ixas.ixa_ifindex = 0;

    if (ira->ira_flags & IRAF_IPSEC_SECURE) {
        /*
         * Apply IPsec based on how IPsec was applied to
         * the packet that was out of the blue.
         */
        if (!ipsec_in_to_out(ira, &ixas, mp, ipha, ip6h)) {
            BUMP_MIB(&ipst->ips_ip_mib, ipIfStatsOutDiscards);
            /* Note: mp already consumed and ip_drop_packet done */
            return;
        }
    } else {
        /*
         * This is in clear. The message we are building
         * here should go out in clear, independent of our policy.
         */
        ixas.ixa_flags |= IXAF_NO_IPSEC;
    }

    (void) ip_output_simple(mp, &ixas);
    ixa_cleanup(&ixas);
}