modules/sctp/sctp.c

/*
 * 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 (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
 */

#include <sys/types.h>
#include <sys/stream.h>
#include <sys/mdb_modapi.h>
#include <sys/socket.h>
#include <sys/list.h>
#include <sys/strsun.h>

#include <mdb/mdb_stdlib.h>

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

#include <inet/common.h>
#include <inet/ip.h>
#include <inet/ip6.h>
#include <inet/ipclassifier.h>

#include <sctp/sctp_impl.h>
#include <sctp/sctp_addr.h>

#define MDB_SCTP_SHOW_FLAGS 0x1
#define MDB_SCTP_DUMP_ADDRS 0x2
#define MDB_SCTP_SHOW_HASH  0x4
#define MDB_SCTP_SHOW_OUT   0x8
#define MDB_SCTP_SHOW_IN    0x10
#define MDB_SCTP_SHOW_MISC  0x20
#define MDB_SCTP_SHOW_RTT   0x40
#define MDB_SCTP_SHOW_STATS 0x80
#define MDB_SCTP_SHOW_FLOW  0x100
#define MDB_SCTP_SHOW_HDR   0x200
#define MDB_SCTP_SHOW_PMTUD 0x400
#define MDB_SCTP_SHOW_RXT   0x800
#define MDB_SCTP_SHOW_CONN  0x1000
#define MDB_SCTP_SHOW_CLOSE 0x2000
#define MDB_SCTP_SHOW_EXT   0x4000

#define MDB_SCTP_SHOW_ALL   0xffffffff

/*
 * Copy from usr/src/uts/common/os/list.c.  Should we have a generic
 * mdb list walker?
 */
#define list_object(a, node) ((void *)(((char *)node) - (a)->list_offset))

static int
ns_to_stackid(uintptr_t kaddr)
{
    netstack_t nss;

    if (mdb_vread(&nss, sizeof (nss), kaddr) == -1) {
        mdb_warn("failed to read netdstack info %p", kaddr);
        return (0);
    }
    return (nss.netstack_stackid);
}

int
sctp_stacks_walk_init(mdb_walk_state_t *wsp)
{
    if (mdb_layered_walk("netstack", wsp) == -1) {
        mdb_warn("can't walk 'netstack'");
        return (WALK_ERR);
    }
    return (WALK_NEXT);
}

int
sctp_stacks_walk_step(mdb_walk_state_t *wsp)
{
    uintptr_t kaddr;
    netstack_t nss;

    if (mdb_vread(&nss, sizeof (nss), wsp->walk_addr) == -1) {
        mdb_warn("can't read netstack at %p", wsp->walk_addr);
        return (WALK_ERR);
    }
    kaddr = (uintptr_t)nss.netstack_modules[NS_SCTP];
    return (wsp->walk_callback(kaddr, wsp->walk_layer, wsp->walk_cbdata));
}

static char *
sctp_faddr_state(int state)
{
    char *statestr;

    switch (state) {
    case SCTP_FADDRS_UNREACH:
        statestr = "Unreachable";
        break;
    case SCTP_FADDRS_DOWN:
        statestr = "Down";
        break;
    case SCTP_FADDRS_ALIVE:
        statestr = "Alive";
        break;
    case SCTP_FADDRS_UNCONFIRMED:
        statestr = "Unconfirmed";
        break;
    default:
        statestr = "Unknown";
        break;
    }
    return (statestr);
}

/* ARGSUSED */
static int
sctp_faddr(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
{
    sctp_faddr_t fa[1];
    char *statestr;

    if (!(flags & DCMD_ADDRSPEC))
        return (DCMD_USAGE);

    if (mdb_vread(fa, sizeof (*fa), addr) == -1) {
        mdb_warn("cannot read fadder at %p", addr);
        return (DCMD_ERR);
    }

    statestr = sctp_faddr_state(fa->sf_state);
    mdb_printf("%<u>%p\t%<b>%N%</b>\t%s%</u>\n", addr, &fa->sf_faddr,
        statestr);
    mdb_printf("next\t\t%?p\tsaddr\t%N\n", fa->sf_next, &fa->sf_saddr);
    mdb_printf("rto\t\t%?d\tsrtt\t\t%?d\n", fa->sf_rto, fa->sf_srtt);
    mdb_printf("rttvar\t\t%?d\trtt_updates\t%?u\n", fa->sf_rttvar,
        fa->sf_rtt_updates);
    mdb_printf("strikes\t\t%?d\tmax_retr\t%?d\n", fa->sf_strikes,
        fa->sf_max_retr);
    mdb_printf("hb_expiry\t%?ld\thb_interval\t%?u\n", fa->sf_hb_expiry,
        fa->sf_hb_interval);
    mdb_printf("pmss\t\t%?u\tcwnd\t\t%?u\n", fa->sf_pmss, fa->sf_cwnd);
    mdb_printf("ssthresh\t%?u\tsuna\t\t%?u\n", fa->sf_ssthresh,
        fa->sf_suna);
    mdb_printf("pba\t\t%?u\tacked\t\t%?u\n", fa->sf_pba, fa->sf_acked);
    mdb_printf("lastactive\t%?ld\thb_secret\t%?#lx\n", fa->sf_lastactive,
        fa->sf_hb_secret);
    mdb_printf("rxt_unacked\t%?u\n", fa->sf_rxt_unacked);
    mdb_printf("timer_mp\t%?p\tixa\t\t%?p\n", fa->sf_timer_mp, fa->sf_ixa);
    mdb_printf("hb_enabled\t%?d\thb_pending\t%?d\n"
        "timer_running\t%?d\tdf\t\t%?d\n"
        "pmtu_discovered\t%?d\tisv4\t\t%?d\n"
        "retransmissions\t%?u\n",
        fa->sf_hb_enabled, fa->sf_hb_pending, fa->sf_timer_running,
        fa->sf_df, fa->sf_pmtu_discovered, fa->sf_isv4, fa->sf_T3expire);

    return (DCMD_OK);
}

static void
print_set(sctp_set_t *sp)
{
    mdb_printf("\tbegin\t%<b>%?x%</b>\t\tend\t%<b>%?x%</b>\n",
        sp->begin, sp->end);
    mdb_printf("\tnext\t%?p\tprev\t%?p\n", sp->next, sp->prev);
}

/* ARGSUSED */
static int
sctp_set(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
{
    sctp_set_t sp[1];

    if (!(flags & DCMD_ADDRSPEC))
        return (DCMD_USAGE);

    if (mdb_vread(sp, sizeof (*sp), addr) == -1)
        return (DCMD_ERR);

    print_set(sp);

    return (DCMD_OK);
}

static void
dump_sack_info(uintptr_t addr)
{
    sctp_set_t sp[1];

    while (addr != 0) {
        if (mdb_vread(sp, sizeof (*sp), addr) == -1) {
            mdb_warn("failed to read sctp_set at %p", addr);
            return;
        }

        addr = (uintptr_t)sp->next;
        print_set(sp);
    }
}

static int
dump_msghdr(mblk_t *meta)
{
    sctp_msg_hdr_t smh;

    if (mdb_vread(&smh, sizeof (smh), (uintptr_t)meta->b_rptr) == -1)
        return (-1);

    mdb_printf("%<u>msg_hdr_t at \t%?p\tsentto\t%?p%</u>\n",
        meta->b_rptr, SCTP_CHUNK_DEST(meta));
    mdb_printf("\tttl\t%?ld\ttob\t%?ld\n", smh.smh_ttl, smh.smh_tob);
    mdb_printf("\tsid\t%?u\tssn\t%?u\n", smh.smh_sid, smh.smh_ssn);
    mdb_printf("\tppid\t%?u\tflags\t%?s\n", smh.smh_ppid,
        smh.smh_flags & MSG_UNORDERED ? "unordered" : " ");
    mdb_printf("\tcontext\t%?u\tmsglen\t%?d\n", smh.smh_context,
        smh.smh_msglen);

    return (0);
}

static int
dump_datahdr(mblk_t *mp)
{
    sctp_data_hdr_t sdc;
    uint16_t        sdh_int16;
    uint32_t        sdh_int32;

    if (mdb_vread(&sdc, sizeof (sdc), (uintptr_t)mp->b_rptr) == -1)
        return (-1);

    mdb_printf("%<u>data_chunk_t \t%?p\tsentto\t%?p%</u>\n",
        mp->b_rptr, SCTP_CHUNK_DEST(mp));
    mdb_printf("\tsent\t%?d\t", SCTP_CHUNK_ISSENT(mp)?1:0);
    mdb_printf("retrans\t%?d\n", SCTP_CHUNK_WANT_REXMIT(mp)?1:0);
    mdb_printf("\tacked\t%?d\t", SCTP_CHUNK_ISACKED(mp)?1:0);
    mdb_printf("sackcnt\t%?u\n", SCTP_CHUNK_SACKCNT(mp));

    mdb_nhconvert(&sdh_int16, &sdc.sdh_len, sizeof (sdc.sdh_len));
    mdb_printf("\tlen\t%?d\t", sdh_int16);
    mdb_printf("BBIT=%d", SCTP_DATA_GET_BBIT(&sdc) == 0 ? 0 : 1);
    mdb_printf("EBIT=%d", SCTP_DATA_GET_EBIT(&sdc) == 0 ? 0 : 1);

    mdb_nhconvert(&sdh_int32, &sdc.sdh_tsn, sizeof (sdc.sdh_tsn));
    mdb_nhconvert(&sdh_int16, &sdc.sdh_sid, sizeof (sdc.sdh_sid));
    mdb_printf("\ttsn\t%?x\tsid\t%?hu\n", sdh_int32, sdh_int16);

    mdb_nhconvert(&sdh_int16, &sdc.sdh_ssn, sizeof (sdc.sdh_ssn));
    mdb_nhconvert(&sdh_int32, &sdc.sdh_payload_id,
        sizeof (sdc.sdh_payload_id));
    mdb_printf("\tssn\t%?hu\tppid\t%?d\n", sdh_int16, sdh_int32);

    return (0);
}

static int
sctp_sent_list(mblk_t *addr)
{
    mblk_t meta, mp;

    if (!addr)
        return (0);

    if (mdb_vread(&meta, sizeof (meta), (uintptr_t)addr) == -1)
        return (-1);

    for (;;) {
        dump_msghdr(&meta);

        if (meta.b_cont == NULL) {
            mdb_printf("No data chunks with message header!\n");
            return (-1);
        }
        if (mdb_vread(&mp, sizeof (mp),
            (uintptr_t)meta.b_cont) == -1) {
            return (-1);
        }
        for (;;) {
            dump_datahdr(&mp);
            if (!mp.b_next)
                break;

            if (mdb_vread(&mp, sizeof (mp),
                (uintptr_t)(mp.b_next)) == -1)
                return (-1);
        }
        if (meta.b_next == NULL)
            break;
        if (mdb_vread(&meta, sizeof (meta),
            (uintptr_t)meta.b_next) == -1)
            return (-1);
    }

    return (0);
}

static int
sctp_unsent_list(mblk_t *addr)
{
    mblk_t meta;

    if (!addr)
        return (0);

    if (mdb_vread(&meta, sizeof (meta), (uintptr_t)addr) == -1)
        return (-1);

    for (;;) {
        dump_msghdr(&meta);

        if (meta.b_next == NULL)
            break;

        if (mdb_vread(&meta, sizeof (meta),
            (uintptr_t)meta.b_next) == -1)
            return (-1);
    }

    return (0);
}

/* ARGSUSED */
static int
sctp_xmit_list(uintptr_t addr, uint_t flags, int ac, const mdb_arg_t *av)
{
    sctp_t sctp;

    if (!(flags & DCMD_ADDRSPEC))
        return (DCMD_USAGE);

    if (mdb_vread(&sctp, sizeof (sctp), addr) == -1)
        return (DCMD_ERR);

    mdb_printf("%<b>Chunkified TX list%</b>\n");
    if (sctp_sent_list(sctp.sctp_xmit_head) < 0)
        return (DCMD_ERR);

    mdb_printf("%<b>Unchunkified TX list%</b>\n");
    if (sctp_unsent_list(sctp.sctp_xmit_unsent) < 0)
        return (DCMD_ERR);

    return (DCMD_OK);
}

/* ARGSUSED */
static int
sctp_mdata_chunk(uintptr_t addr, uint_t flags, int ac, const mdb_arg_t *av)
{
    sctp_data_hdr_t dc;
    mblk_t mp;

    if (!(flags & DCMD_ADDRSPEC))
        return (DCMD_USAGE);

    if (mdb_vread(&mp, sizeof (mp), addr) == -1)
        return (DCMD_ERR);

    if (mdb_vread(&dc, sizeof (dc), (uintptr_t)mp.b_rptr) == -1)
        return (DCMD_ERR);

    mdb_printf("%<b>%-?p%</b>tsn\t%?x\tsid\t%?hu\n", addr,
        dc.sdh_tsn, dc.sdh_sid);
    mdb_printf("%-?sssn\t%?hu\tppid\t%?x\n", "", dc.sdh_ssn,
        dc.sdh_payload_id);

    return (DCMD_OK);
}

/* ARGSUSED */
static int
sctp_istr_msgs(uintptr_t addr, uint_t flags, int ac, const mdb_arg_t *av)
{
    mblk_t          istrmp;
    mblk_t          dmp;
    sctp_data_hdr_t     dp;
    uintptr_t       daddr;
    uintptr_t       chaddr;
    boolean_t       bbit;
    boolean_t       ebit;

    if (!(flags & DCMD_ADDRSPEC))
        return (DCMD_USAGE);

    do {
        if (mdb_vread(&istrmp, sizeof (istrmp), addr) == -1)
            return (DCMD_ERR);

        mdb_printf("\tistr mblk at %p: next: %?p\n"
            "\t\tprev: %?p\tcont: %?p\n", addr, istrmp.b_next,
            istrmp.b_prev, istrmp.b_cont);
        daddr = (uintptr_t)&istrmp;
        do {
            if (mdb_vread(&dmp, sizeof (dmp), daddr) == -1)
                break;
            chaddr = (uintptr_t)dmp.b_rptr;
            if (mdb_vread(&dp, sizeof (dp), chaddr) == -1)
                break;

            bbit = (SCTP_DATA_GET_BBIT(&dp) != 0);
            ebit = (SCTP_DATA_GET_EBIT(&dp) != 0);

            mdb_printf("\t\t\ttsn: %x  bbit: %d  ebit: %d\n",
                dp.sdh_tsn, bbit, ebit);


            daddr = (uintptr_t)dmp.b_cont;
        } while (daddr != NULL);

        addr = (uintptr_t)istrmp.b_next;
    } while (addr != NULL);

    return (DCMD_OK);
}

/* ARGSUSED */
static int
sctp_reass_list(uintptr_t addr, uint_t flags, int ac, const mdb_arg_t *av)
{
    sctp_reass_t srp;
    mblk_t srpmp;
    sctp_data_hdr_t dp;
    mblk_t dmp;
    uintptr_t daddr;
    uintptr_t chaddr;
    boolean_t bbit, ebit;

    if (!(flags & DCMD_ADDRSPEC))
        return (DCMD_USAGE);

    do {
        if (mdb_vread(&srpmp, sizeof (srpmp), addr) == -1)
            return (DCMD_ERR);

        if (mdb_vread(&srp, sizeof (srp),
            (uintptr_t)srpmp.b_datap->db_base) == -1)
            return (DCMD_ERR);

        mdb_printf("\treassembly mblk at %p: next: %?p\n"
            "\t\tprev: %?p\tcont: %?p\n", addr, srpmp.b_next,
            srpmp.b_prev, srpmp.b_cont);
        mdb_printf("\t\tssn: %hu\tneeded: %hu\tgot: %hu\ttail: %?p\n"
            "\t\tpartial_delivered: %s\n", srp.sr_ssn, srp.sr_needed,
            srp.sr_got, srp.sr_tail, srp.sr_partial_delivered ? "TRUE" :
            "FALSE");

        /* display the contents of this ssn's reassemby list */
        daddr = DB_TYPE(&srpmp) == M_CTL ? (uintptr_t)srpmp.b_cont :
            (uintptr_t)&srpmp;
        do {
            if (mdb_vread(&dmp, sizeof (dmp), daddr) == -1)
                break;
            chaddr = (uintptr_t)dmp.b_rptr;
            if (mdb_vread(&dp, sizeof (dp), chaddr) == -1)
                break;

            bbit = (SCTP_DATA_GET_BBIT(&dp) != 0);
            ebit = (SCTP_DATA_GET_EBIT(&dp) != 0);

            mdb_printf("\t\t\ttsn: %x  bbit: %d  ebit: %d\n",
                dp.sdh_tsn, bbit, ebit);

            daddr = (uintptr_t)dmp.b_cont;
        } while (daddr != NULL);

        addr = (uintptr_t)srpmp.b_next;
    } while (addr != NULL);

    return (DCMD_OK);
}

/* ARGSUSED */
static int
sctp_uo_reass_list(uintptr_t addr, uint_t flags, int ac, const mdb_arg_t *av)
{
    sctp_data_hdr_t dp;
    mblk_t      dmp;
    uintptr_t   chaddr;
    boolean_t   bbit;
    boolean_t   ebit;
    boolean_t   ubit;

    if (!(flags & DCMD_ADDRSPEC))
        return (DCMD_USAGE);

    do {
        if (mdb_vread(&dmp, sizeof (dmp), addr) == -1)
            return (DCMD_ERR);

        mdb_printf("\treassembly mblk at %p: next: %?p\n"
            "\t\tprev: %?p\n", addr, dmp.b_next, dmp.b_prev);

        chaddr = (uintptr_t)dmp.b_rptr;
        if (mdb_vread(&dp, sizeof (dp), chaddr) == -1)
            break;

        bbit = (SCTP_DATA_GET_BBIT(&dp) != 0);
        ebit = (SCTP_DATA_GET_EBIT(&dp) != 0);
        ubit = (SCTP_DATA_GET_UBIT(&dp) != 0);

        mdb_printf("\t\t\tsid: %hu ssn: %hu tsn: %x "
            "flags: %x (U=%d B=%d E=%d)\n", dp.sdh_sid, dp.sdh_ssn,
            dp.sdh_tsn, dp.sdh_flags, ubit, bbit, ebit);

        addr = (uintptr_t)dmp.b_next;
    } while (addr != NULL);

    return (DCMD_OK);
}

static int
sctp_instr(uintptr_t addr, uint_t flags, int ac, const mdb_arg_t *av)
{
    sctp_instr_t sip;

    if (!(flags & DCMD_ADDRSPEC))
        return (DCMD_USAGE);

    if (mdb_vread(&sip, sizeof (sip), addr) == -1)
        return (DCMD_ERR);

    mdb_printf("%<b>%-?p%</b>\n\tmsglist\t%?p\tnmsgs\t%?d\n"
        "\tnextseq\t%?d\treass\t%?p\n", addr, sip.istr_msgs,
        sip.istr_nmsgs, sip.nextseq, sip.istr_reass);
    mdb_set_dot(addr + sizeof (sip));

    return (sctp_reass_list((uintptr_t)sip.istr_reass, flags, ac, av));
}

static const char *
state2str(sctp_t *sctp)
{
    switch (sctp->sctp_state) {
    case SCTPS_IDLE:        return ("SCTPS_IDLE");
    case SCTPS_BOUND:       return ("SCTPS_BOUND");
    case SCTPS_LISTEN:      return ("SCTPS_LISTEN");
    case SCTPS_COOKIE_WAIT:     return ("SCTPS_COOKIE_WAIT");
    case SCTPS_COOKIE_ECHOED:   return ("SCTPS_COOKIE_ECHOED");
    case SCTPS_ESTABLISHED:     return ("SCTPS_ESTABLISHED");
    case SCTPS_SHUTDOWN_PENDING:    return ("SCTPS_SHUTDOWN_PENDING");
    case SCTPS_SHUTDOWN_SENT:   return ("SCTPS_SHUTDOWN_SENT");
    case SCTPS_SHUTDOWN_RECEIVED:   return ("SCTPS_SHUTDOWN_RECEIVED");
    case SCTPS_SHUTDOWN_ACK_SENT:   return ("SCTPS_SHUTDOWN_ACK_SENT");
    default:            return ("UNKNOWN STATE");
    }
}

static void
show_sctp_flags(sctp_t *sctp)
{
    mdb_printf("\tunderstands_asconf\t%d\n",
        sctp->sctp_understands_asconf);
    mdb_printf("\tdebug\t\t\t%d\n", sctp->sctp_connp->conn_debug);
    mdb_printf("\tcchunk_pend\t\t%d\n", sctp->sctp_cchunk_pend);
    mdb_printf("\tdgram_errind\t\t%d\n",
        sctp->sctp_connp->conn_dgram_errind);

    mdb_printf("\tlinger\t\t\t%d\n", sctp->sctp_connp->conn_linger);
    if (sctp->sctp_lingering)
        return;
    mdb_printf("\tlingering\t\t%d\n", sctp->sctp_lingering);
    mdb_printf("\tloopback\t\t%d\n", sctp->sctp_loopback);
    mdb_printf("\tforce_sack\t\t%d\n", sctp->sctp_force_sack);

    mdb_printf("\tack_timer_runing\t%d\n", sctp->sctp_ack_timer_running);
    mdb_printf("\trecvdstaddr\t\t%d\n",
        sctp->sctp_connp->conn_recv_ancillary.crb_recvdstaddr);
    mdb_printf("\thwcksum\t\t\t%d\n", sctp->sctp_hwcksum);
    mdb_printf("\tunderstands_addip\t%d\n", sctp->sctp_understands_addip);

    mdb_printf("\tbound_to_all\t\t%d\n", sctp->sctp_bound_to_all);
    mdb_printf("\tcansleep\t\t%d\n", sctp->sctp_cansleep);
    mdb_printf("\tdetached\t\t%d\n", sctp->sctp_detached);
    mdb_printf("\tsend_adaptation\t\t%d\n", sctp->sctp_send_adaptation);

    mdb_printf("\trecv_adaptation\t\t%d\n", sctp->sctp_recv_adaptation);
    mdb_printf("\tndelay\t\t\t%d\n", sctp->sctp_ndelay);
    mdb_printf("\tcondemned\t\t%d\n", sctp->sctp_condemned);
    mdb_printf("\tchk_fast_rexmit\t\t%d\n", sctp->sctp_chk_fast_rexmit);

    mdb_printf("\tprsctp_aware\t\t%d\n", sctp->sctp_prsctp_aware);
    mdb_printf("\tlinklocal\t\t%d\n", sctp->sctp_linklocal);
    mdb_printf("\trexmitting\t\t%d\n", sctp->sctp_rexmitting);
    mdb_printf("\tzero_win_probe\t\t%d\n", sctp->sctp_zero_win_probe);

    mdb_printf("\trecvsndrcvinfo\t\t%d\n", sctp->sctp_recvsndrcvinfo);
    mdb_printf("\trecvassocevnt\t\t%d\n", sctp->sctp_recvassocevnt);
    mdb_printf("\trecvpathevnt\t\t%d\n", sctp->sctp_recvpathevnt);
    mdb_printf("\trecvsendfailevnt\t%d\n", sctp->sctp_recvsendfailevnt);

    mdb_printf("\trecvpeerevnt\t\t%d\n", sctp->sctp_recvpeererr);
    mdb_printf("\trecvchutdownevnt\t%d\n", sctp->sctp_recvshutdownevnt);
    mdb_printf("\trecvcpdnevnt\t\t%d\n", sctp->sctp_recvpdevnt);
    mdb_printf("\trecvcalevnt\t\t%d\n\n", sctp->sctp_recvalevnt);
}

/*
 * Given a sctp_saddr_ipif_t, print out its address.  This assumes
 * that addr contains the sctp_addr_ipif_t structure already and this
 * function does not need to read it in.
 */
/* ARGSUSED */
static int
print_saddr(uintptr_t ptr, const void *addr, void *cbdata)
{
    sctp_saddr_ipif_t *saddr = (sctp_saddr_ipif_t *)addr;
    sctp_ipif_t ipif;
    char *statestr;

    /* Read in the sctp_ipif object */
    if (mdb_vread(&ipif, sizeof (ipif), (uintptr_t)saddr->saddr_ipifp) ==
        -1) {
        mdb_warn("cannot read ipif at %p", saddr->saddr_ipifp);
        return (WALK_ERR);
    }

    switch (ipif.sctp_ipif_state) {
    case SCTP_IPIFS_CONDEMNED:
        statestr = "Condemned";
        break;
    case SCTP_IPIFS_INVALID:
        statestr = "Invalid";
        break;
    case SCTP_IPIFS_DOWN:
        statestr = "Down";
        break;
    case SCTP_IPIFS_UP:
        statestr = "Up";
        break;
    default:
        statestr = "Unknown";
        break;
    }
    mdb_printf("\t%p\t%N% (%s", saddr->saddr_ipifp, &ipif.sctp_ipif_saddr,
        statestr);
    if (saddr->saddr_ipif_dontsrc == 1)
        mdb_printf("/Dontsrc");
    if (saddr->saddr_ipif_unconfirmed == 1)
        mdb_printf("/Unconfirmed");
    if (saddr->saddr_ipif_delete_pending == 1)
        mdb_printf("/DeletePending");
    mdb_printf(")\n");
    mdb_printf("\t\t\tid %d zoneid %d IPIF flags %x\n",
        ipif.sctp_ipif_id,
        ipif.sctp_ipif_zoneid, ipif.sctp_ipif_flags);
    return (WALK_NEXT);
}

/*
 * Given a sctp_faddr_t, print out its address.  This assumes that
 * addr contains the sctp_faddr_t structure already and this function
 * does not need to read it in.
 */
static int
print_faddr(uintptr_t ptr, const void *addr, void *cbdata)
{
    char    *statestr;
    sctp_faddr_t *faddr = (sctp_faddr_t *)addr;
    int *i = cbdata;

    statestr = sctp_faddr_state(faddr->sf_state);

    mdb_printf("\t%d:\t%N\t%?p (%s)\n", (*i)++, &faddr->sf_faddr, ptr,
        statestr);
    return (WALK_NEXT);
}

int
sctp(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
{
    sctp_t sctps, *sctp;
    conn_t conns, *connp;
    int i;
    uint_t opts = 0;
    uint_t paddr = 0;
    in_port_t lport, fport;

    if (!(flags & DCMD_ADDRSPEC))
        return (DCMD_USAGE);

    if (mdb_vread(&sctps, sizeof (sctps), addr) == -1) {
        mdb_warn("failed to read sctp_t at: %p\n", addr);
        return (DCMD_ERR);
    }
    sctp = &sctps;

    if (mdb_vread(&conns, sizeof (conns),
        (uintptr_t)sctp->sctp_connp) == -1) {
        mdb_warn("failed to read conn_t at: %p\n", sctp->sctp_connp);
        return (DCMD_ERR);
    }

    connp = &conns;

    connp->conn_sctp = sctp;
    sctp->sctp_connp = connp;

    if (mdb_getopts(argc, argv,
        'a', MDB_OPT_SETBITS, MDB_SCTP_SHOW_ALL, &opts,
        'f', MDB_OPT_SETBITS, MDB_SCTP_SHOW_FLAGS, &opts,
        'h', MDB_OPT_SETBITS, MDB_SCTP_SHOW_HASH, &opts,
        'o', MDB_OPT_SETBITS, MDB_SCTP_SHOW_OUT, &opts,
        'i', MDB_OPT_SETBITS, MDB_SCTP_SHOW_IN, &opts,
        'm', MDB_OPT_SETBITS, MDB_SCTP_SHOW_MISC, &opts,
        'r', MDB_OPT_SETBITS, MDB_SCTP_SHOW_RTT, &opts,
        'S', MDB_OPT_SETBITS, MDB_SCTP_SHOW_STATS, &opts,
        'F', MDB_OPT_SETBITS, MDB_SCTP_SHOW_FLOW, &opts,
        'H', MDB_OPT_SETBITS, MDB_SCTP_SHOW_HDR, &opts,
        'p', MDB_OPT_SETBITS, MDB_SCTP_SHOW_PMTUD, &opts,
        'R', MDB_OPT_SETBITS, MDB_SCTP_SHOW_RXT, &opts,
        'C', MDB_OPT_SETBITS, MDB_SCTP_SHOW_CONN, &opts,
        'c', MDB_OPT_SETBITS, MDB_SCTP_SHOW_CLOSE, &opts,
        'e', MDB_OPT_SETBITS, MDB_SCTP_SHOW_EXT, &opts,
        'P', MDB_OPT_SETBITS, 1, &paddr,
        'd', MDB_OPT_SETBITS, MDB_SCTP_DUMP_ADDRS, &opts) != argc) {
        return (DCMD_USAGE);
    }

    /* non-verbose faddrs, suitable for pipelines to sctp_faddr */
    if (paddr != 0) {
        sctp_faddr_t faddr, *fp;
        for (fp = sctp->sctp_faddrs; fp != NULL; fp = faddr.sf_next) {
            if (mdb_vread(&faddr, sizeof (faddr), (uintptr_t)fp)
                == -1) {
                mdb_warn("failed to read faddr at %p",
                    fp);
                return (DCMD_ERR);
            }
            mdb_printf("%p\n", fp);
        }
        return (DCMD_OK);
    }

    mdb_nhconvert(&lport, &connp->conn_lport, sizeof (lport));
    mdb_nhconvert(&fport, &connp->conn_fport, sizeof (fport));
    mdb_printf("%<u>%p% %22s S=%-6hu D=%-6hu% STACK=%d ZONE=%d%</u>", addr,
        state2str(sctp), lport, fport,
        ns_to_stackid((uintptr_t)connp->conn_netstack), connp->conn_zoneid);

    if (sctp->sctp_faddrs) {
        sctp_faddr_t faddr;
        if (mdb_vread(&faddr, sizeof (faddr),
            (uintptr_t)sctp->sctp_faddrs) != -1)
            mdb_printf("%<u> %N%</u>", &faddr.sf_faddr);
    }
    mdb_printf("\n");

    if (opts & MDB_SCTP_DUMP_ADDRS) {
        mdb_printf("%<b>Local and Peer Addresses%</b>\n");

        /* Display source addresses */
        mdb_printf("nsaddrs\t\t%?d\n", sctp->sctp_nsaddrs);
        (void) mdb_pwalk("sctp_walk_saddr", print_saddr, NULL, addr);

        /* Display peer addresses */
        mdb_printf("nfaddrs\t\t%?d\n", sctp->sctp_nfaddrs);
        i = 1;
        (void) mdb_pwalk("sctp_walk_faddr", print_faddr, &i, addr);

        mdb_printf("lastfaddr\t%?p\tprimary\t\t%?p\n",
            sctp->sctp_lastfaddr, sctp->sctp_primary);
        mdb_printf("current\t\t%?p\tlastdata\t%?p\n",
            sctp->sctp_current, sctp->sctp_lastdata);
    }

    if (opts & MDB_SCTP_SHOW_OUT) {
        mdb_printf("%<b>Outbound Data%</b>\n");
        mdb_printf("xmit_head\t%?p\txmit_tail\t%?p\n",
            sctp->sctp_xmit_head, sctp->sctp_xmit_tail);
        mdb_printf("xmit_unsent\t%?p\txmit_unsent_tail%?p\n",
            sctp->sctp_xmit_unsent, sctp->sctp_xmit_unsent_tail);
        mdb_printf("xmit_unacked\t%?p\n", sctp->sctp_xmit_unacked);
        mdb_printf("unacked\t\t%?u\tunsent\t\t%?ld\n",
            sctp->sctp_unacked, sctp->sctp_unsent);
        mdb_printf("ltsn\t\t%?x\tlastack_rxd\t%?x\n",
            sctp->sctp_ltsn, sctp->sctp_lastack_rxd);
        mdb_printf("recovery_tsn\t%?x\tadv_pap\t\t%?x\n",
            sctp->sctp_recovery_tsn, sctp->sctp_adv_pap);
        mdb_printf("num_ostr\t%?hu\tostrcntrs\t%?p\n",
            sctp->sctp_num_ostr, sctp->sctp_ostrcntrs);
        mdb_printf("pad_mp\t\t%?p\terr_chunks\t%?p\n",
            sctp->sctp_pad_mp, sctp->sctp_err_chunks);
        mdb_printf("err_len\t\t%?u\n", sctp->sctp_err_len);

        mdb_printf("%<b>Default Send Parameters%</b>\n");
        mdb_printf("def_stream\t%?u\tdef_flags\t%?x\n",
            sctp->sctp_def_stream, sctp->sctp_def_flags);
        mdb_printf("def_ppid\t%?x\tdef_context\t%?x\n",
            sctp->sctp_def_ppid, sctp->sctp_def_context);
        mdb_printf("def_timetolive\t%?u\n",
            sctp->sctp_def_timetolive);
    }

    if (opts & MDB_SCTP_SHOW_IN) {
        mdb_printf("%<b>Inbound Data%</b>\n");
        mdb_printf("sack_info\t%?p\tsack_gaps\t%?d\n",
            sctp->sctp_sack_info, sctp->sctp_sack_gaps);
        dump_sack_info((uintptr_t)sctp->sctp_sack_info);
        mdb_printf("ftsn\t\t%?x\tlastacked\t%?x\n",
            sctp->sctp_ftsn, sctp->sctp_lastacked);
        mdb_printf("istr_nmsgs\t%?d\tsack_toggle\t%?d\n",
            sctp->sctp_istr_nmsgs, sctp->sctp_sack_toggle);
        mdb_printf("ack_mp\t\t%?p\n", sctp->sctp_ack_mp);
        mdb_printf("num_istr\t%?hu\tinstr\t\t%?p\n",
            sctp->sctp_num_istr, sctp->sctp_instr);
        mdb_printf("unord_reass\t%?p\n", sctp->sctp_uo_frags);
    }

    if (opts & MDB_SCTP_SHOW_RTT) {
        mdb_printf("%<b>RTT Tracking%</b>\n");
        mdb_printf("rtt_tsn\t\t%?x\tout_time\t%?ld\n",
            sctp->sctp_rtt_tsn, sctp->sctp_out_time);
    }

    if (opts & MDB_SCTP_SHOW_FLOW) {
        mdb_printf("%<b>Flow Control%</b>\n");
        mdb_printf("tconn_sndbuf\t%?d\n"
            "conn_sndlowat\t%?d\tfrwnd\t\t%?u\n"
            "rwnd\t\t%?u\tlast advertised rwnd\t%?u\n"
            "rxqueued\t%?u\tcwnd_max\t%?u\n", connp->conn_sndbuf,
            connp->conn_sndlowat, sctp->sctp_frwnd,
            sctp->sctp_rwnd, sctp->sctp_arwnd, sctp->sctp_rxqueued,
            sctp->sctp_cwnd_max);
    }

    if (opts & MDB_SCTP_SHOW_HDR) {
        mdb_printf("%<b>Composite Headers%</b>\n");
        mdb_printf("iphc\t\t%?p\tiphc6\t\t%?p\n"
            "iphc_len\t%?d\tiphc6_len\t%?d\n"
            "hdr_len\t\t%?d\thdr6_len\t%?d\n"
            "ipha\t\t%?p\tip6h\t\t%?p\n"
            "ip_hdr_len\t%?d\tip_hdr6_len\t%?d\n"
            "sctph\t\t%?p\tsctph6\t\t%?p\n"
            "lvtag\t\t%?x\tfvtag\t\t%?x\n", sctp->sctp_iphc,
            sctp->sctp_iphc6, sctp->sctp_iphc_len,
            sctp->sctp_iphc6_len, sctp->sctp_hdr_len,
            sctp->sctp_hdr6_len, sctp->sctp_ipha, sctp->sctp_ip6h,
            sctp->sctp_ip_hdr_len, sctp->sctp_ip_hdr6_len,
            sctp->sctp_sctph, sctp->sctp_sctph6, sctp->sctp_lvtag,
            sctp->sctp_fvtag);
    }

    if (opts & MDB_SCTP_SHOW_PMTUD) {
        mdb_printf("%<b>PMTUd%</b>\n");
        mdb_printf("last_mtu_probe\t%?ld\tmtu_probe_intvl\t%?ld\n"
            "mss\t\t%?u\n",
            sctp->sctp_last_mtu_probe, sctp->sctp_mtu_probe_intvl,
            sctp->sctp_mss);
    }

    if (opts & MDB_SCTP_SHOW_RXT) {
        mdb_printf("%<b>Retransmit Info%</b>\n");
        mdb_printf("cookie_mp\t%?p\tstrikes\t\t%?d\n"
            "max_init_rxt\t%?d\tpa_max_rxt\t%?d\n"
            "pp_max_rxt\t%?d\trto_max\t\t%?u\n"
            "rto_min\t\t%?u\trto_initial\t%?u\n"
            "init_rto_max\t%?u\n"
            "rxt_nxttsn\t%?u\trxt_maxtsn\t%?u\n", sctp->sctp_cookie_mp,
            sctp->sctp_strikes, sctp->sctp_max_init_rxt,
            sctp->sctp_pa_max_rxt, sctp->sctp_pp_max_rxt,
            sctp->sctp_rto_max, sctp->sctp_rto_min,
            sctp->sctp_rto_initial, sctp->sctp_rto_max_init,
            sctp->sctp_rxt_nxttsn, sctp->sctp_rxt_maxtsn);
    }

    if (opts & MDB_SCTP_SHOW_CONN) {
        mdb_printf("%<b>Connection State%</b>\n");
        mdb_printf("last_secret_update%?ld\n",
            sctp->sctp_last_secret_update);

        mdb_printf("secret\t\t");
        for (i = 0; i < SCTP_SECRET_LEN; i++) {
            if (i % 2 == 0)
                mdb_printf("0x%02x", sctp->sctp_secret[i]);
            else
                mdb_printf("%02x ", sctp->sctp_secret[i]);
        }
        mdb_printf("\n");
        mdb_printf("old_secret\t");
        for (i = 0; i < SCTP_SECRET_LEN; i++) {
            if (i % 2 == 0)
                mdb_printf("0x%02x", sctp->sctp_old_secret[i]);
            else
                mdb_printf("%02x ", sctp->sctp_old_secret[i]);
        }
        mdb_printf("\n");
    }

    if (opts & MDB_SCTP_SHOW_STATS) {
        mdb_printf("%<b>Stats Counters%</b>\n");
        mdb_printf("opkts\t\t%?llu\tobchunks\t%?llu\n"
            "odchunks\t%?llu\toudchunks\t%?llu\n"
            "rxtchunks\t%?llu\tT1expire\t%?lu\n"
            "T2expire\t%?lu\tT3expire\t%?lu\n"
            "msgcount\t%?llu\tprsctpdrop\t%?llu\n"
            "AssocStartTime\t%?lu\n",
            sctp->sctp_opkts, sctp->sctp_obchunks,
            sctp->sctp_odchunks, sctp->sctp_oudchunks,
            sctp->sctp_rxtchunks, sctp->sctp_T1expire,
            sctp->sctp_T2expire, sctp->sctp_T3expire,
            sctp->sctp_msgcount, sctp->sctp_prsctpdrop,
            sctp->sctp_assoc_start_time);
        mdb_printf("ipkts\t\t%?llu\tibchunks\t%?llu\n"
            "idchunks\t%?llu\tiudchunks\t%?llu\n"
            "fragdmsgs\t%?llu\treassmsgs\t%?llu\n",
            sctp->sctp_ipkts, sctp->sctp_ibchunks,
            sctp->sctp_idchunks, sctp->sctp_iudchunks,
            sctp->sctp_fragdmsgs, sctp->sctp_reassmsgs);
    }

    if (opts & MDB_SCTP_SHOW_HASH) {
        mdb_printf("%<b>Hash Tables%</b>\n");
        mdb_printf("conn_hash_next\t%?p\t", sctp->sctp_conn_hash_next);
        mdb_printf("conn_hash_prev\t%?p\n", sctp->sctp_conn_hash_prev);

        mdb_printf("listen_hash_next%?p\t",
            sctp->sctp_listen_hash_next);
        mdb_printf("listen_hash_prev%?p\n",
            sctp->sctp_listen_hash_prev);
        mdb_nhconvert(&lport, &connp->conn_lport, sizeof (lport));
        mdb_printf("[ listen_hash bucket\t%?d ]\n",
            SCTP_LISTEN_HASH(lport));

        mdb_printf("conn_tfp\t%?p\t", sctp->sctp_conn_tfp);
        mdb_printf("listen_tfp\t%?p\n", sctp->sctp_listen_tfp);

        mdb_printf("bind_hash\t%?p\tptpbhn\t\t%?p\n",
            sctp->sctp_bind_hash, sctp->sctp_ptpbhn);
        mdb_printf("bind_lockp\t%?p\n",
            sctp->sctp_bind_lockp);
        mdb_printf("[ bind_hash bucket\t%?d ]\n",
            SCTP_BIND_HASH(lport));
    }

    if (opts & MDB_SCTP_SHOW_CLOSE) {
        mdb_printf("%<b>Cleanup / Close%</b>\n");
        mdb_printf("shutdown_faddr\t%?p\tclient_errno\t%?d\n"
            "lingertime\t%?d\trefcnt\t\t%?hu\n",
            sctp->sctp_shutdown_faddr, sctp->sctp_client_errno,
            connp->conn_lingertime, sctp->sctp_refcnt);
    }

    if (opts & MDB_SCTP_SHOW_MISC) {
        mdb_printf("%<b>Miscellaneous%</b>\n");
        mdb_printf("bound_if\t%?u\theartbeat_mp\t%?p\n"
            "family\t\t%?u\tipversion\t%?hu\n"
            "hb_interval\t%?u\tautoclose\t%?d\n"
            "active\t\t%?ld\ttx_adaptation_code%?x\n"
            "rx_adaptation_code%?x\ttimer_mp\t%?p\n"
            "partial_delivery_point\t%?d\n",
            connp->conn_bound_if, sctp->sctp_heartbeat_mp,
            connp->conn_family,
            connp->conn_ipversion,
            sctp->sctp_hb_interval, sctp->sctp_autoclose,
            sctp->sctp_active, sctp->sctp_tx_adaptation_code,
            sctp->sctp_rx_adaptation_code, sctp->sctp_timer_mp,
            sctp->sctp_pd_point);
    }

    if (opts & MDB_SCTP_SHOW_EXT) {
        mdb_printf("%<b>Extensions and Reliable Ctl Chunks%</b>\n");
        mdb_printf("cxmit_list\t%?p\tlcsn\t\t%?x\n"
            "fcsn\t\t%?x\n", sctp->sctp_cxmit_list, sctp->sctp_lcsn,
            sctp->sctp_fcsn);
    }

    if (opts & MDB_SCTP_SHOW_FLAGS) {
        mdb_printf("%<b>Flags%</b>\n");
        show_sctp_flags(sctp);
    }

    return (DCMD_OK);
}

typedef struct fanout_walk_data {
    int index;
    int size;
    uintptr_t sctp;
    sctp_tf_t *fanout;
    uintptr_t (*getnext)(sctp_t *);
} fanout_walk_data_t;

typedef struct fanout_init {
    const char *nested_walker_name;
    size_t offset;  /* for what used to be a symbol */
    int (*getsize)(sctp_stack_t *);
    uintptr_t (*getnext)(sctp_t *);
} fanout_init_t;

static uintptr_t
listen_next(sctp_t *sctp)
{
    return ((uintptr_t)sctp->sctp_listen_hash_next);
}

/* ARGSUSED */
static int
listen_size(sctp_stack_t *sctps)
{
    return (SCTP_LISTEN_FANOUT_SIZE);
}

static uintptr_t
conn_next(sctp_t *sctp)
{
    return ((uintptr_t)sctp->sctp_conn_hash_next);
}

static int
conn_size(sctp_stack_t *sctps)
{
    int size;
    uintptr_t kaddr;

    kaddr = (uintptr_t)&sctps->sctps_conn_hash_size;

    if (mdb_vread(&size, sizeof (size), kaddr) == -1) {
        mdb_warn("can't read 'sctps_conn_hash_size' at %p", kaddr);
        return (1);
    }
    return (size);
}

static uintptr_t
bind_next(sctp_t *sctp)
{
    return ((uintptr_t)sctp->sctp_bind_hash);
}

/* ARGSUSED */
static int
bind_size(sctp_stack_t *sctps)
{
    return (SCTP_BIND_FANOUT_SIZE);
}

static intptr_t
find_next_hash_item(fanout_walk_data_t *fw)
{
    sctp_tf_t tf;
    sctp_t sctp;

    /* first try to continue down the hash chain */
    if (fw->sctp != NULL) {
        /* try to get next in hash chain */
        if (mdb_vread(&sctp, sizeof (sctp), fw->sctp) == -1) {
            mdb_warn("failed to read sctp at %p", fw->sctp);
            return (NULL);
        }
        fw->sctp = fw->getnext(&sctp);
        if (fw->sctp != NULL)
            return (fw->sctp);
        else
            /* end of chain; go to next bucket */
            fw->index++;
    }

    /* find a new hash chain, traversing the buckets */
    for (; fw->index < fw->size; fw->index++) {
        /* read the current hash line for an sctp */
        if (mdb_vread(&tf, sizeof (tf),
            (uintptr_t)(fw->fanout + fw->index)) == -1) {
            mdb_warn("failed to read tf at %p",
                fw->fanout + fw->index);
            return (NULL);
        }
        if (tf.tf_sctp != NULL) {
            /* start of a new chain */
            fw->sctp = (uintptr_t)tf.tf_sctp;
            return (fw->sctp);
        }
    }
    return (NULL);
}

static int
fanout_stack_walk_init(mdb_walk_state_t *wsp)
{
    fanout_walk_data_t *lw;
    fanout_init_t *fi = wsp->walk_arg;
    sctp_stack_t *sctps = (sctp_stack_t *)wsp->walk_addr;
    uintptr_t kaddr;

    if (mdb_vread(&kaddr, sizeof (kaddr),
        wsp->walk_addr + fi->offset) == -1) {
        mdb_warn("can't read sctp fanout at %p",
            wsp->walk_addr + fi->offset);
        return (WALK_ERR);
    }

    lw = mdb_alloc(sizeof (*lw), UM_SLEEP);
    lw->index = 0;
    lw->size = fi->getsize(sctps);
    lw->sctp = NULL;
    lw->fanout = (sctp_tf_t *)kaddr;
    lw->getnext = fi->getnext;

    if ((wsp->walk_addr = find_next_hash_item(lw)) == NULL) {
        return (WALK_DONE);
    }
    wsp->walk_data = lw;
    return (WALK_NEXT);
}

static int
fanout_stack_walk_step(mdb_walk_state_t *wsp)
{
    fanout_walk_data_t *fw = wsp->walk_data;
    uintptr_t addr = wsp->walk_addr;
    sctp_t sctp;
    int status;

    if (mdb_vread(&sctp, sizeof (sctp), addr) == -1) {
        mdb_warn("failed to read sctp at %p", addr);
        return (WALK_DONE);
    }

    status = wsp->walk_callback(addr, &sctp, wsp->walk_cbdata);
    if (status != WALK_NEXT)
        return (status);

    if ((wsp->walk_addr = find_next_hash_item(fw)) == NULL)
        return (WALK_DONE);

    return (WALK_NEXT);
}

static void
fanout_stack_walk_fini(mdb_walk_state_t *wsp)
{
    fanout_walk_data_t *fw = wsp->walk_data;

    mdb_free(fw, sizeof (*fw));
}

int
fanout_walk_init(mdb_walk_state_t *wsp)
{
    if (mdb_layered_walk("sctp_stacks", wsp) == -1) {
        mdb_warn("can't walk 'sctp_stacks'");
        return (WALK_ERR);
    }

    return (WALK_NEXT);
}

int
fanout_walk_step(mdb_walk_state_t *wsp)
{
    fanout_init_t *fi = wsp->walk_arg;

    if (mdb_pwalk(fi->nested_walker_name, wsp->walk_callback,
        wsp->walk_cbdata, wsp->walk_addr) == -1) {
        mdb_warn("couldn't walk '%s'for address %p",
            fi->nested_walker_name, wsp->walk_addr);
        return (WALK_ERR);
    }
    return (WALK_NEXT);
}

int
sctps_walk_init(mdb_walk_state_t *wsp)
{

    if (mdb_layered_walk("sctp_stacks", wsp) == -1) {
        mdb_warn("can't walk 'sctp_stacks'");
        return (WALK_ERR);
    }

    return (WALK_NEXT);
}

int
sctps_walk_step(mdb_walk_state_t *wsp)
{
    uintptr_t kaddr;

    kaddr = wsp->walk_addr + OFFSETOF(sctp_stack_t, sctps_g_list);
    if (mdb_pwalk("list", wsp->walk_callback,
        wsp->walk_cbdata, kaddr) == -1) {
        mdb_warn("couldn't walk 'list' for address %p", kaddr);
        return (WALK_ERR);
    }
    return (WALK_NEXT);
}

static int
sctp_walk_faddr_init(mdb_walk_state_t *wsp)
{
    sctp_t sctp;

    if (wsp->walk_addr == NULL)
        return (WALK_ERR);

    if (mdb_vread(&sctp, sizeof (sctp), wsp->walk_addr) == -1) {
        mdb_warn("failed to read sctp at %p", wsp->walk_addr);
        return (WALK_ERR);
    }
    if ((wsp->walk_addr = (uintptr_t)sctp.sctp_faddrs) != NULL)
        return (WALK_NEXT);
    else
        return (WALK_DONE);
}

static int
sctp_walk_faddr_step(mdb_walk_state_t *wsp)
{
    uintptr_t faddr_ptr = wsp->walk_addr;
    sctp_faddr_t sctp_faddr;
    int status;

    if (mdb_vread(&sctp_faddr, sizeof (sctp_faddr_t), faddr_ptr) == -1) {
        mdb_warn("failed to read sctp_faddr_t at %p", faddr_ptr);
        return (WALK_ERR);
    }
    status = wsp->walk_callback(faddr_ptr, &sctp_faddr, wsp->walk_cbdata);
    if (status != WALK_NEXT)
        return (status);
    if ((faddr_ptr = (uintptr_t)sctp_faddr.sf_next) == NULL) {
        return (WALK_DONE);
    } else {
        wsp->walk_addr = faddr_ptr;
        return (WALK_NEXT);
    }
}

/*
 * Helper structure for sctp_walk_saddr.  It stores the sctp_t being walked,
 * the current index to the sctp_saddrs[], and the current count of the
 * sctp_saddr_ipif_t list.
 */
typedef struct {
    sctp_t  sctp;
    int hash_index;
    int cur_cnt;
} saddr_walk_t;

static int
sctp_walk_saddr_init(mdb_walk_state_t *wsp)
{
    sctp_t *sctp;
    int i;
    saddr_walk_t *swalker;

    if (wsp->walk_addr == NULL)
        return (WALK_ERR);

    swalker = mdb_alloc(sizeof (saddr_walk_t), UM_SLEEP);
    sctp = &swalker->sctp;
    if (mdb_vread(sctp, sizeof (sctp_t), wsp->walk_addr) == -1) {
        mdb_warn("failed to read sctp at %p", wsp->walk_addr);
        mdb_free(swalker, sizeof (saddr_walk_t));
        return (WALK_ERR);
    }

    /* Find the first source address. */
    for (i = 0; i < SCTP_IPIF_HASH; i++) {
        if (sctp->sctp_saddrs[i].ipif_count > 0) {
            list_t *addr_list;

            addr_list = &sctp->sctp_saddrs[i].sctp_ipif_list;
            wsp->walk_addr = (uintptr_t)list_object(addr_list,
                addr_list->list_head.list_next);

            /* Recode the current info */
            swalker->hash_index = i;
            swalker->cur_cnt = 1;
            wsp->walk_data = swalker;

            return (WALK_NEXT);
        }
    }
    return (WALK_DONE);
}

static int
sctp_walk_saddr_step(mdb_walk_state_t *wsp)
{
    uintptr_t saddr_ptr = wsp->walk_addr;
    sctp_saddr_ipif_t saddr;
    saddr_walk_t *swalker;
    sctp_t *sctp;
    int status;
    int i, j;

    if (mdb_vread(&saddr, sizeof (sctp_saddr_ipif_t), saddr_ptr) == -1) {
        mdb_warn("failed to read sctp_saddr_ipif_t at %p", saddr_ptr);
        return (WALK_ERR);
    }
    status = wsp->walk_callback(saddr_ptr, &saddr, wsp->walk_cbdata);
    if (status != WALK_NEXT)
        return (status);

    swalker = (saddr_walk_t *)wsp->walk_data;
    sctp = &swalker->sctp;
    i = swalker->hash_index;
    j = swalker->cur_cnt;

    /*
     * If there is still a source address in the current list, return it.
     * Otherwise, go to the next list in the sctp_saddrs[].
     */
    if (j++ < sctp->sctp_saddrs[i].ipif_count) {
        wsp->walk_addr = (uintptr_t)saddr.saddr_ipif.list_next;
        swalker->cur_cnt = j;
        return (WALK_NEXT);
    } else {
        list_t *lst;

        for (i = i + 1; i < SCTP_IPIF_HASH; i++) {
            if (sctp->sctp_saddrs[i].ipif_count > 0) {
                lst = &sctp->sctp_saddrs[i].sctp_ipif_list;
                wsp->walk_addr = (uintptr_t)list_object(
                    lst, lst->list_head.list_next);
                swalker->hash_index = i;
                swalker->cur_cnt = 1;
                return (WALK_NEXT);
            }
        }
    }
    return (WALK_DONE);
}

static void
sctp_walk_saddr_fini(mdb_walk_state_t *wsp)
{
    saddr_walk_t *swalker = (saddr_walk_t *)wsp->walk_data;

    mdb_free(swalker, sizeof (saddr_walk_t));
}


typedef struct ill_walk_data {
    sctp_ill_hash_t ills[SCTP_ILL_HASH];
    uint32_t    count;
} ill_walk_data_t;

typedef struct ipuf_walk_data {
    sctp_ipif_hash_t ipifs[SCTP_IPIF_HASH];
    uint32_t    count;
} ipif_walk_data_t;


int
sctp_ill_walk_init(mdb_walk_state_t *wsp)
{
    if (mdb_layered_walk("sctp_stacks", wsp) == -1) {
        mdb_warn("can't walk 'sctp_stacks'");
        return (WALK_ERR);
    }

    return (WALK_NEXT);
}

int
sctp_ill_walk_step(mdb_walk_state_t *wsp)
{
    if (mdb_pwalk("sctp_stack_walk_ill", wsp->walk_callback,
        wsp->walk_cbdata, wsp->walk_addr) == -1) {
        mdb_warn("couldn't walk 'sctp_stack_walk_ill' for addr %p",
            wsp->walk_addr);
        return (WALK_ERR);
    }
    return (WALK_NEXT);
}

/*
 * wsp->walk_addr is the address of sctps_ill_list
 */
static int
sctp_stack_ill_walk_init(mdb_walk_state_t *wsp)
{
    ill_walk_data_t iw;
    intptr_t i;
    uintptr_t kaddr, uaddr;
    size_t offset;

    kaddr = wsp->walk_addr + OFFSETOF(sctp_stack_t, sctps_ills_count);
    if (mdb_vread(&iw.count, sizeof (iw.count), kaddr) == -1) {
        mdb_warn("can't read sctps_ills_count at %p", kaddr);
        return (WALK_ERR);
    }
    kaddr = wsp->walk_addr + OFFSETOF(sctp_stack_t, sctps_g_ills);

    if (mdb_vread(&kaddr, sizeof (kaddr), kaddr) == -1) {
        mdb_warn("can't read scpts_g_ills %p", kaddr);
        return (WALK_ERR);
    }
    if (mdb_vread(&iw.ills, sizeof (iw.ills), kaddr) == -1) {
        mdb_warn("failed to read 'sctps_g_ills'");
        return (NULL);
    }

    /* Find the first ill. */
    for (i = 0; i < SCTP_ILL_HASH; i++) {
        if (iw.ills[i].ill_count > 0) {
            uaddr = (uintptr_t)&iw.ills[i].sctp_ill_list;
            offset = uaddr - (uintptr_t)&iw.ills;
            if (mdb_pwalk("list", wsp->walk_callback,
                wsp->walk_cbdata, kaddr+offset) == -1) {
                mdb_warn("couldn't walk 'list' for address %p",
                    kaddr);
                return (WALK_ERR);
            }
        }
    }
    return (WALK_DONE);
}

static int
sctp_stack_ill_walk_step(mdb_walk_state_t *wsp)
{
    return (wsp->walk_callback(wsp->walk_addr, wsp->walk_layer,
        wsp->walk_cbdata));
}

int
sctp_ipif_walk_init(mdb_walk_state_t *wsp)
{
    if (mdb_layered_walk("sctp_stacks", wsp) == -1) {
        mdb_warn("can't walk 'sctp_stacks'");
        return (WALK_ERR);
    }
    return (WALK_NEXT);
}

int
sctp_ipif_walk_step(mdb_walk_state_t *wsp)
{
    if (mdb_pwalk("sctp_stack_walk_ipif", wsp->walk_callback,
        wsp->walk_cbdata, wsp->walk_addr) == -1) {
        mdb_warn("couldn't walk 'sctp_stack_walk_ipif' for addr %p",
            wsp->walk_addr);
        return (WALK_ERR);
    }
    return (WALK_NEXT);
}

/*
 * wsp->walk_addr is the address of sctps_ipif_list
 */
static int
sctp_stack_ipif_walk_init(mdb_walk_state_t *wsp)
{
    ipif_walk_data_t iw;
    intptr_t i;
    uintptr_t kaddr, uaddr;
    size_t offset;

    kaddr = wsp->walk_addr + OFFSETOF(sctp_stack_t, sctps_g_ipifs_count);
    if (mdb_vread(&iw.count, sizeof (iw.count), kaddr) == -1) {
        mdb_warn("can't read sctps_g_ipifs_count at %p", kaddr);
        return (WALK_ERR);
    }
    kaddr = wsp->walk_addr + OFFSETOF(sctp_stack_t, sctps_g_ipifs);

    if (mdb_vread(&kaddr, sizeof (kaddr), kaddr) == -1) {
        mdb_warn("can't read scpts_g_ipifs %p", kaddr);
        return (WALK_ERR);
    }
    if (mdb_vread(&iw.ipifs, sizeof (iw.ipifs), kaddr) == -1) {
        mdb_warn("failed to read 'sctps_g_ipifs'");
        return (NULL);
    }

    /* Find the first ipif. */
    for (i = 0; i < SCTP_IPIF_HASH; i++) {
        if (iw.ipifs[i].ipif_count > 0) {
            uaddr = (uintptr_t)&iw.ipifs[i].sctp_ipif_list;
            offset = uaddr - (uintptr_t)&iw.ipifs;
            if (mdb_pwalk("list", wsp->walk_callback,
                wsp->walk_cbdata, kaddr+offset) == -1) {
                mdb_warn("couldn't walk 'list' for address %p",
                    kaddr);
                return (WALK_ERR);
            }
        }
    }
    return (WALK_DONE);
}

static int
sctp_stack_ipif_walk_step(mdb_walk_state_t *wsp)
{
    return (wsp->walk_callback(wsp->walk_addr, wsp->walk_layer,
        wsp->walk_cbdata));
}

/*
 * Initialization function for the per CPU SCTP stats counter walker of a given
 * SCTP stack.
 */
int
sctps_sc_walk_init(mdb_walk_state_t *wsp)
{
    sctp_stack_t sctps;

    if (wsp->walk_addr == NULL)
        return (WALK_ERR);

    if (mdb_vread(&sctps, sizeof (sctps), wsp->walk_addr) == -1) {
        mdb_warn("failed to read sctp_stack_t at %p", wsp->walk_addr);
        return (WALK_ERR);
    }
    if (sctps.sctps_sc_cnt == 0)
        return (WALK_DONE);

    /*
     * Store the sctp_stack_t pointer in walk_data.  The stepping function
     * used it to calculate if the end of the counter has reached.
     */
    wsp->walk_data = (void *)wsp->walk_addr;
    wsp->walk_addr = (uintptr_t)sctps.sctps_sc;
    return (WALK_NEXT);
}

/*
 * Stepping function for the per CPU SCTP stats counterwalker.
 */
int
sctps_sc_walk_step(mdb_walk_state_t *wsp)
{
    int status;
    sctp_stack_t sctps;
    sctp_stats_cpu_t *stats;
    char *next, *end;

    if (mdb_vread(&sctps, sizeof (sctps), (uintptr_t)wsp->walk_data) ==
        -1) {
        mdb_warn("failed to read sctp_stack_t at %p", wsp->walk_addr);
        return (WALK_ERR);
    }
    if (mdb_vread(&stats, sizeof (stats), wsp->walk_addr) == -1) {
        mdb_warn("failed ot read sctp_stats_cpu_t at %p",
            wsp->walk_addr);
        return (WALK_ERR);
    }
    status = wsp->walk_callback((uintptr_t)stats, &stats, wsp->walk_cbdata);
    if (status != WALK_NEXT)
        return (status);

    next = (char *)wsp->walk_addr + sizeof (sctp_stats_cpu_t *);
    end = (char *)sctps.sctps_sc + sctps.sctps_sc_cnt *
        sizeof (sctp_stats_cpu_t *);
    if (next >= end)
        return (WALK_DONE);
    wsp->walk_addr = (uintptr_t)next;
    return (WALK_NEXT);
}

static void
sctp_help(void)
{
    mdb_printf("Print information for a given SCTP sctp_t\n\n");
    mdb_printf("Options:\n");
    mdb_printf("\t-a\t All the information\n");
    mdb_printf("\t-f\t Flags\n");
    mdb_printf("\t-h\t Hash Tables\n");
    mdb_printf("\t-o\t Outbound Data\n");
    mdb_printf("\t-i\t Inbound Data\n");
    mdb_printf("\t-m\t Miscellaneous Information\n");
    mdb_printf("\t-r\t RTT Tracking\n");
    mdb_printf("\t-S\t Stats Counters\n");
    mdb_printf("\t-F\t Flow Control\n");
    mdb_printf("\t-H\t Composite Headers\n");
    mdb_printf("\t-p\t PMTUD\n");
    mdb_printf("\t-R\t Retransmit Information\n");
    mdb_printf("\t-C\t Connection State\n");
    mdb_printf("\t-c\t Cleanup / Close\n");
    mdb_printf("\t-e\t Extensions and Reliable Control Chunks\n");
    mdb_printf("\t-d\t Local and Peer addresses\n");
    mdb_printf("\t-P\t Peer addresses\n");
}

static const mdb_dcmd_t dcmds[] = {
    { "sctp", ":[-afhoimrSFHpRCcedP]",
        "display sctp control structure", sctp, sctp_help },
    { "sctp_set", ":", "display a SCTP set", sctp_set },
    { "sctp_faddr", ":", "display a faddr", sctp_faddr },
    { "sctp_istr_msgs", ":", "display msg list on an instream",
        sctp_istr_msgs },
    { "sctp_mdata_chunk", ":", "display a data chunk in an mblk",
        sctp_mdata_chunk },
    { "sctp_xmit_list", ":", "display sctp xmit lists", sctp_xmit_list },
    { "sctp_instr", ":", "display instr", sctp_instr },
    { "sctp_reass_list", ":", "display reass list", sctp_reass_list },
    { "sctp_uo_reass_list", ":", "display un-ordered reass list",
        sctp_uo_reass_list },
    { NULL }
};

static const fanout_init_t listen_fanout_init = {
    "sctp_stack_listen_fanout", OFFSETOF(sctp_stack_t, sctps_listen_fanout),
    listen_size, listen_next
};

static const fanout_init_t conn_fanout_init = {
    "sctp_stack_conn_fanout",  OFFSETOF(sctp_stack_t, sctps_conn_fanout),
    conn_size, conn_next
};

static const fanout_init_t bind_fanout_init = {
    "sctp_stack_bind_fanout", OFFSETOF(sctp_stack_t, sctps_bind_fanout),
    bind_size, bind_next
};

static const mdb_walker_t walkers[] = {
    { "sctps", "walk the full chain of sctps for all stacks",
        sctps_walk_init, sctps_walk_step, NULL },
    { "sctp_listen_fanout", "walk the sctp listen fanout for all stacks",
        fanout_walk_init, fanout_walk_step, NULL,
        (void *)&listen_fanout_init },
    { "sctp_conn_fanout", "walk the sctp conn fanout for all stacks",
        fanout_walk_init, fanout_walk_step, NULL,
        (void *)&conn_fanout_init },
    { "sctp_bind_fanout", "walk the sctp bind fanout for all stacks",
        fanout_walk_init, fanout_walk_step, NULL,
        (void *)&bind_fanout_init },
    { "sctp_stack_listen_fanout",
        "walk the sctp listen fanout for one stack",
        fanout_stack_walk_init, fanout_stack_walk_step,
        fanout_stack_walk_fini,
        (void *)&listen_fanout_init },
    { "sctp_stack_conn_fanout", "walk the sctp conn fanout for one stack",
        fanout_stack_walk_init, fanout_stack_walk_step,
        fanout_stack_walk_fini,
        (void *)&conn_fanout_init },
    { "sctp_stack_bind_fanout", "walk the sctp bind fanoutfor one stack",
        fanout_stack_walk_init, fanout_stack_walk_step,
        fanout_stack_walk_fini,
        (void *)&bind_fanout_init },
    { "sctp_walk_faddr", "walk the peer address list of a given sctp_t",
        sctp_walk_faddr_init, sctp_walk_faddr_step, NULL },
    { "sctp_walk_saddr", "walk the local address list of a given sctp_t",
        sctp_walk_saddr_init, sctp_walk_saddr_step, sctp_walk_saddr_fini },
    { "sctp_walk_ill", "walk the sctp_g_ills list for all stacks",
        sctp_ill_walk_init, sctp_ill_walk_step, NULL },
    { "sctp_walk_ipif", "walk the sctp_g_ipif list for all stacks",
        sctp_ipif_walk_init, sctp_ipif_walk_step, NULL },
    { "sctp_stack_walk_ill", "walk the sctp_g_ills list for one stack",
        sctp_stack_ill_walk_init, sctp_stack_ill_walk_step, NULL },
    { "sctp_stack_walk_ipif", "walk the sctp_g_ipif list for one stack",
        sctp_stack_ipif_walk_init, sctp_stack_ipif_walk_step, NULL },
    { "sctps_sc", "walk all the per CPU stats counters of a sctp_stack_t",
        sctps_sc_walk_init, sctps_sc_walk_step, NULL },
    { NULL }
};

static const mdb_modinfo_t modinfo = { MDB_API_VERSION, dcmds, walkers };

const mdb_modinfo_t *
_mdb_init(void)
{
    return (&modinfo);
}