/*
 * 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 2010 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 * Copyright (c) 2012 Nexenta Systems, Inc. All rights reserved.
 * Copyright 2017 Joyent, Inc.
 */

#include <sys/types.h>
#include <sys/stream.h>
#include <sys/stropts.h>
#include <sys/errno.h>
#include <sys/strlog.h>
#include <sys/tihdr.h>
#include <sys/socket.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/mkdev.h>
#include <sys/kmem.h>
#include <sys/zone.h>
#include <sys/sysmacros.h>
#include <sys/cmn_err.h>
#include <sys/vtrace.h>
#include <sys/debug.h>
#include <sys/atomic.h>
#include <sys/strsun.h>
#include <sys/random.h>
#include <netinet/in.h>
#include <net/if.h>
#include <netinet/ip6.h>
#include <netinet/icmp6.h>
#include <net/pfkeyv2.h>
#include <net/pfpolicy.h>

#include <inet/common.h>
#include <inet/mi.h>
#include <inet/ip.h>
#include <inet/ip6.h>
#include <inet/nd.h>
#include <inet/ip_if.h>
#include <inet/ip_ndp.h>
#include <inet/ipsec_info.h>
#include <inet/ipsec_impl.h>
#include <inet/sadb.h>
#include <inet/ipsecah.h>
#include <inet/ipsec_impl.h>
#include <inet/ipdrop.h>
#include <sys/taskq.h>
#include <sys/policy.h>
#include <sys/strsun.h>

#include <sys/crypto/common.h>
#include <sys/crypto/api.h>
#include <sys/kstat.h>
#include <sys/strsubr.h>

#include <sys/tsol/tnet.h>

/*
 * Table of ND variables supported by ipsecah. These are loaded into
 * ipsecah_g_nd in ipsecah_init_nd.
 * All of these are alterable, within the min/max values given, at run time.
 */
static  ipsecahparam_t  lcl_param_arr[] = {
        /* min  max                     value   name */
        { 0,    3,                      0,      "ipsecah_debug"},
        { 125,  32000, SADB_AGE_INTERVAL_DEFAULT,       "ipsecah_age_interval"},
        { 1,    10,                     1,      "ipsecah_reap_delay"},
        { 1,    SADB_MAX_REPLAY,        64,     "ipsecah_replay_size"},
        { 1,    300,                    15,     "ipsecah_acquire_timeout"},
        { 1,    1800,                   90,     "ipsecah_larval_timeout"},
        /* Default lifetime values for ACQUIRE messages. */
        { 0,    0xffffffffU,            0,      "ipsecah_default_soft_bytes"},
        { 0,    0xffffffffU,            0,      "ipsecah_default_hard_bytes"},
        { 0,    0xffffffffU,            24000,  "ipsecah_default_soft_addtime"},
        { 0,    0xffffffffU,            28800,  "ipsecah_default_hard_addtime"},
        { 0,    0xffffffffU,            0,      "ipsecah_default_soft_usetime"},
        { 0,    0xffffffffU,            0,      "ipsecah_default_hard_usetime"},
        { 0,    1,                      0,      "ipsecah_log_unknown_spi"},
};

#define ah0dbg(a)       printf a
/* NOTE:  != 0 instead of > 0 so lint doesn't complain. */
#define ah1dbg(ahstack, a)      if (ahstack->ipsecah_debug != 0) printf a
#define ah2dbg(ahstack, a)      if (ahstack->ipsecah_debug > 1) printf a
#define ah3dbg(ahstack, a)      if (ahstack->ipsecah_debug > 2) printf a

/*
 * XXX This is broken. Padding should be determined dynamically
 * depending on the ICV size and IP version number so that the
 * total AH header size is a multiple of 32 bits or 64 bits
 * for V4 and V6 respectively. For 96bit ICVs we have no problems.
 * Anything different from that, we need to fix our code.
 */
#define IPV4_PADDING_ALIGN      0x04    /* Multiple of 32 bits */
#define IPV6_PADDING_ALIGN      0x04    /* Multiple of 32 bits */

/*
 * Helper macro. Avoids a call to msgdsize if there is only one
 * mblk in the chain.
 */
#define AH_MSGSIZE(mp) ((mp)->b_cont != NULL ? msgdsize(mp) : MBLKL(mp))


static mblk_t *ah_auth_out_done(mblk_t *, ip_xmit_attr_t *, ipsec_crypto_t *);
static mblk_t *ah_auth_in_done(mblk_t *, ip_recv_attr_t *, ipsec_crypto_t *);
static mblk_t *ah_process_ip_options_v4(mblk_t *, ipsa_t *, int *, uint_t,
    boolean_t, ipsecah_stack_t *);
static mblk_t *ah_process_ip_options_v6(mblk_t *, ipsa_t *, int *, uint_t,
    boolean_t, ipsecah_stack_t *);
static void ah_getspi(mblk_t *, keysock_in_t *, ipsecah_stack_t *);
static void ah_inbound_restart(mblk_t *, ip_recv_attr_t *);

static mblk_t *ah_outbound(mblk_t *, ip_xmit_attr_t *);
static void ah_outbound_finish(mblk_t *, ip_xmit_attr_t *);

static int ipsecah_open(queue_t *, dev_t *, int, int, cred_t *);
static int ipsecah_close(queue_t *, int, cred_t *);
static int ipsecah_rput(queue_t *, mblk_t *);
static int ipsecah_wput(queue_t *, mblk_t *);
static boolean_t ah_register_out(uint32_t, uint32_t, uint_t, ipsecah_stack_t *,
    cred_t *);
static void     *ipsecah_stack_init(netstackid_t stackid, netstack_t *ns);
static void     ipsecah_stack_fini(netstackid_t stackid, void *arg);

/* Setable in /etc/system */
uint32_t ah_hash_size = IPSEC_DEFAULT_HASH_SIZE;

static taskq_t *ah_taskq;

static struct module_info info = {
        5136, "ipsecah", 0, INFPSZ, 65536, 1024
};

static struct qinit rinit = {
        ipsecah_rput, NULL, ipsecah_open, ipsecah_close, NULL, &info,
        NULL
};

static struct qinit winit = {
        ipsecah_wput, NULL, ipsecah_open, ipsecah_close, NULL, &info,
        NULL
};

struct streamtab ipsecahinfo = {
        &rinit, &winit, NULL, NULL
};

static int ah_kstat_update(kstat_t *, int);

uint64_t ipsacq_maxpackets = IPSACQ_MAXPACKETS;

static boolean_t
ah_kstat_init(ipsecah_stack_t *ahstack, netstackid_t stackid)
{
        ipsec_stack_t   *ipss = ahstack->ipsecah_netstack->netstack_ipsec;

        ahstack->ah_ksp = kstat_create_netstack("ipsecah", 0, "ah_stat", "net",
            KSTAT_TYPE_NAMED, sizeof (ah_kstats_t) / sizeof (kstat_named_t), 0,
            stackid);

        if (ahstack->ah_ksp == NULL || ahstack->ah_ksp->ks_data == NULL)
                return (B_FALSE);

        ahstack->ah_kstats = ahstack->ah_ksp->ks_data;

        ahstack->ah_ksp->ks_update = ah_kstat_update;
        ahstack->ah_ksp->ks_private = (void *)(uintptr_t)stackid;

#define K64 KSTAT_DATA_UINT64
#define KI(x) kstat_named_init(&(ahstack->ah_kstats->ah_stat_##x), #x, K64)

        KI(num_aalgs);
        KI(good_auth);
        KI(bad_auth);
        KI(replay_failures);
        KI(replay_early_failures);
        KI(keysock_in);
        KI(out_requests);
        KI(acquire_requests);
        KI(bytes_expired);
        KI(out_discards);
        KI(crypto_sync);
        KI(crypto_async);
        KI(crypto_failures);

#undef KI
#undef K64

        kstat_install(ahstack->ah_ksp);
        IP_ACQUIRE_STAT(ipss, maxpackets, ipsacq_maxpackets);
        return (B_TRUE);
}

static int
ah_kstat_update(kstat_t *kp, int rw)
{
        ah_kstats_t     *ekp;
        netstackid_t    stackid;
        netstack_t      *ns;
        ipsec_stack_t   *ipss;

        if ((kp == NULL) || (kp->ks_data == NULL))
                return (EIO);

        if (rw == KSTAT_WRITE)
                return (EACCES);

        stackid = (netstackid_t)(uintptr_t)kp->ks_private;
        ns = netstack_find_by_stackid(stackid);
        if (ns == NULL)
                return (-1);
        ipss = ns->netstack_ipsec;
        if (ipss == NULL) {
                netstack_rele(ns);
                return (-1);
        }
        ekp = (ah_kstats_t *)kp->ks_data;

        rw_enter(&ipss->ipsec_alg_lock, RW_READER);
        ekp->ah_stat_num_aalgs.value.ui64 = ipss->ipsec_nalgs[IPSEC_ALG_AUTH];
        rw_exit(&ipss->ipsec_alg_lock);

        netstack_rele(ns);
        return (0);
}

/*
 * Don't have to lock ipsec_age_interval, as only one thread will access it at
 * a time, because I control the one function that does a qtimeout() on
 * ah_pfkey_q.
 */
static void
ah_ager(void *arg)
{
        ipsecah_stack_t *ahstack = (ipsecah_stack_t *)arg;
        netstack_t      *ns = ahstack->ipsecah_netstack;
        hrtime_t begin = gethrtime();

        sadb_ager(&ahstack->ah_sadb.s_v4, ahstack->ah_pfkey_q,
            ahstack->ipsecah_reap_delay, ns);
        sadb_ager(&ahstack->ah_sadb.s_v6, ahstack->ah_pfkey_q,
            ahstack->ipsecah_reap_delay, ns);

        ahstack->ah_event = sadb_retimeout(begin, ahstack->ah_pfkey_q,
            ah_ager, ahstack,
            &ahstack->ipsecah_age_interval, ahstack->ipsecah_age_int_max,
            info.mi_idnum);
}

/*
 * Get an AH NDD parameter.
 */
/* ARGSUSED */
static int
ipsecah_param_get(
    queue_t     *q,
    mblk_t      *mp,
    caddr_t     cp,
    cred_t *cr)
{
        ipsecahparam_t  *ipsecahpa = (ipsecahparam_t *)cp;
        uint_t value;
        ipsecah_stack_t *ahstack = (ipsecah_stack_t *)q->q_ptr;

        mutex_enter(&ahstack->ipsecah_param_lock);
        value = ipsecahpa->ipsecah_param_value;
        mutex_exit(&ahstack->ipsecah_param_lock);

        (void) mi_mpprintf(mp, "%u", value);
        return (0);
}

/*
 * This routine sets an NDD variable in a ipsecahparam_t structure.
 */
/* ARGSUSED */
static int
ipsecah_param_set(
    queue_t     *q,
    mblk_t      *mp,
    char        *value,
    caddr_t     cp,
    cred_t *cr)
{
        ulong_t new_value;
        ipsecahparam_t  *ipsecahpa = (ipsecahparam_t *)cp;
        ipsecah_stack_t *ahstack = (ipsecah_stack_t *)q->q_ptr;

        /*
         * Fail the request if the new value does not lie within the
         * required bounds.
         */
        if (ddi_strtoul(value, NULL, 10, &new_value) != 0 ||
            new_value < ipsecahpa->ipsecah_param_min ||
            new_value > ipsecahpa->ipsecah_param_max) {
                return (EINVAL);
        }

        /* Set the new value */
        mutex_enter(&ahstack->ipsecah_param_lock);
        ipsecahpa->ipsecah_param_value = new_value;
        mutex_exit(&ahstack->ipsecah_param_lock);
        return (0);
}

/*
 * Using lifetime NDD variables, fill in an extended combination's
 * lifetime information.
 */
void
ipsecah_fill_defs(sadb_x_ecomb_t *ecomb, netstack_t *ns)
{
        ipsecah_stack_t *ahstack = ns->netstack_ipsecah;

        ecomb->sadb_x_ecomb_soft_bytes = ahstack->ipsecah_default_soft_bytes;
        ecomb->sadb_x_ecomb_hard_bytes = ahstack->ipsecah_default_hard_bytes;
        ecomb->sadb_x_ecomb_soft_addtime =
            ahstack->ipsecah_default_soft_addtime;
        ecomb->sadb_x_ecomb_hard_addtime =
            ahstack->ipsecah_default_hard_addtime;
        ecomb->sadb_x_ecomb_soft_usetime =
            ahstack->ipsecah_default_soft_usetime;
        ecomb->sadb_x_ecomb_hard_usetime =
            ahstack->ipsecah_default_hard_usetime;
}

/*
 * Initialize things for AH at module load time.
 */
boolean_t
ipsecah_ddi_init(void)
{
        ah_taskq = taskq_create("ah_taskq", 1, minclsyspri,
            IPSEC_TASKQ_MIN, IPSEC_TASKQ_MAX, 0);

        /*
         * We want to be informed each time a stack is created or
         * destroyed in the kernel, so we can maintain the
         * set of ipsecah_stack_t's.
         */
        netstack_register(NS_IPSECAH, ipsecah_stack_init, NULL,
            ipsecah_stack_fini);

        return (B_TRUE);
}

/*
 * Walk through the param array specified registering each element with the
 * named dispatch handler.
 */
static boolean_t
ipsecah_param_register(IDP *ndp, ipsecahparam_t *ahp, int cnt)
{
        for (; cnt-- > 0; ahp++) {
                if (ahp->ipsecah_param_name != NULL &&
                    ahp->ipsecah_param_name[0]) {
                        if (!nd_load(ndp,
                            ahp->ipsecah_param_name,
                            ipsecah_param_get, ipsecah_param_set,
                            (caddr_t)ahp)) {
                                nd_free(ndp);
                                return (B_FALSE);
                        }
                }
        }
        return (B_TRUE);
}

/*
 * Initialize things for AH for each stack instance
 */
static void *
ipsecah_stack_init(netstackid_t stackid, netstack_t *ns)
{
        ipsecah_stack_t *ahstack;
        ipsecahparam_t  *ahp;

        ahstack = (ipsecah_stack_t *)kmem_zalloc(sizeof (*ahstack), KM_SLEEP);
        ahstack->ipsecah_netstack = ns;

        ahp = (ipsecahparam_t *)kmem_alloc(sizeof (lcl_param_arr), KM_SLEEP);
        ahstack->ipsecah_params = ahp;
        bcopy(lcl_param_arr, ahp, sizeof (lcl_param_arr));

        (void) ipsecah_param_register(&ahstack->ipsecah_g_nd, ahp,
            A_CNT(lcl_param_arr));

        (void) ah_kstat_init(ahstack, stackid);

        ahstack->ah_sadb.s_acquire_timeout = &ahstack->ipsecah_acquire_timeout;
        sadbp_init("AH", &ahstack->ah_sadb, SADB_SATYPE_AH, ah_hash_size,
            ahstack->ipsecah_netstack);

        mutex_init(&ahstack->ipsecah_param_lock, NULL, MUTEX_DEFAULT, 0);

        ip_drop_register(&ahstack->ah_dropper, "IPsec AH");
        return (ahstack);
}

/*
 * Destroy things for AH at module unload time.
 */
void
ipsecah_ddi_destroy(void)
{
        netstack_unregister(NS_IPSECAH);
        taskq_destroy(ah_taskq);
}

/*
 * Destroy things for AH for one stack... Never called?
 */
static void
ipsecah_stack_fini(netstackid_t stackid, void *arg)
{
        ipsecah_stack_t *ahstack = (ipsecah_stack_t *)arg;

        if (ahstack->ah_pfkey_q != NULL) {
                (void) quntimeout(ahstack->ah_pfkey_q, ahstack->ah_event);
        }
        ahstack->ah_sadb.s_acquire_timeout = NULL;
        sadbp_destroy(&ahstack->ah_sadb, ahstack->ipsecah_netstack);
        ip_drop_unregister(&ahstack->ah_dropper);
        mutex_destroy(&ahstack->ipsecah_param_lock);
        nd_free(&ahstack->ipsecah_g_nd);

        kmem_free(ahstack->ipsecah_params, sizeof (lcl_param_arr));
        ahstack->ipsecah_params = NULL;
        kstat_delete_netstack(ahstack->ah_ksp, stackid);
        ahstack->ah_ksp = NULL;
        ahstack->ah_kstats = NULL;

        kmem_free(ahstack, sizeof (*ahstack));
}

/*
 * AH module open routine, which is here for keysock plumbing.
 * Keysock is pushed over {AH,ESP} which is an artifact from the Bad Old
 * Days of export control, and fears that ESP would not be allowed
 * to be shipped at all by default.  Eventually, keysock should
 * either access AH and ESP via modstubs or krtld dependencies, or
 * perhaps be folded in with AH and ESP into a single IPsec/netsec
 * module ("netsec" if PF_KEY provides more than AH/ESP keying tables).
 */
/* ARGSUSED */
static int
ipsecah_open(queue_t *q, dev_t *devp, int flag, int sflag, cred_t *credp)
{
        netstack_t      *ns;
        ipsecah_stack_t *ahstack;

        if (secpolicy_ip_config(credp, B_FALSE) != 0)
                return (EPERM);

        if (q->q_ptr != NULL)
                return (0);  /* Re-open of an already open instance. */

        if (sflag != MODOPEN)
                return (EINVAL);

        ns = netstack_find_by_cred(credp);
        ASSERT(ns != NULL);
        ahstack = ns->netstack_ipsecah;
        ASSERT(ahstack != NULL);

        q->q_ptr = ahstack;
        WR(q)->q_ptr = q->q_ptr;

        qprocson(q);
        return (0);
}

/*
 * AH module close routine.
 */
/* ARGSUSED */
static int
ipsecah_close(queue_t *q, int flags __unused, cred_t *credp __unused)
{
        ipsecah_stack_t *ahstack = (ipsecah_stack_t *)q->q_ptr;

        /*
         * Clean up q_ptr, if needed.
         */
        qprocsoff(q);

        /* Keysock queue check is safe, because of OCEXCL perimeter. */

        if (q == ahstack->ah_pfkey_q) {
                ah1dbg(ahstack,
                    ("ipsecah_close:  Ummm... keysock is closing AH.\n"));
                ahstack->ah_pfkey_q = NULL;
                /* Detach qtimeouts. */
                (void) quntimeout(q, ahstack->ah_event);
        }

        netstack_rele(ahstack->ipsecah_netstack);
        return (0);
}

/*
 * Construct an SADB_REGISTER message with the current algorithms.
 */
static boolean_t
ah_register_out(uint32_t sequence, uint32_t pid, uint_t serial,
    ipsecah_stack_t *ahstack, cred_t *cr)
{
        mblk_t *mp;
        boolean_t rc = B_TRUE;
        sadb_msg_t *samsg;
        sadb_supported_t *sasupp;
        sadb_alg_t *saalg;
        uint_t allocsize = sizeof (*samsg);
        uint_t i, numalgs_snap;
        ipsec_alginfo_t **authalgs;
        uint_t num_aalgs;
        ipsec_stack_t   *ipss = ahstack->ipsecah_netstack->netstack_ipsec;
        sadb_sens_t *sens;
        size_t sens_len = 0;
        sadb_ext_t *nextext;
        ts_label_t *sens_tsl = NULL;

        /* Allocate the KEYSOCK_OUT. */
        mp = sadb_keysock_out(serial);
        if (mp == NULL) {
                ah0dbg(("ah_register_out: couldn't allocate mblk.\n"));
                return (B_FALSE);
        }

        if (is_system_labeled() && (cr != NULL)) {
                sens_tsl = crgetlabel(cr);
                if (sens_tsl != NULL) {
                        sens_len = sadb_sens_len_from_label(sens_tsl);
                        allocsize += sens_len;
                }
        }

        /*
         * Allocate the PF_KEY message that follows KEYSOCK_OUT.
         * The alg reader lock needs to be held while allocating
         * the variable part (i.e. the algorithms) of the message.
         */

        rw_enter(&ipss->ipsec_alg_lock, RW_READER);

        /*
         * Return only valid algorithms, so the number of algorithms
         * to send up may be less than the number of algorithm entries
         * in the table.
         */
        authalgs = ipss->ipsec_alglists[IPSEC_ALG_AUTH];
        for (num_aalgs = 0, i = 0; i < IPSEC_MAX_ALGS; i++)
                if (authalgs[i] != NULL && ALG_VALID(authalgs[i]))
                        num_aalgs++;

        /*
         * Fill SADB_REGISTER message's algorithm descriptors.  Hold
         * down the lock while filling it.
         */
        if (num_aalgs != 0) {
                allocsize += (num_aalgs * sizeof (*saalg));
                allocsize += sizeof (*sasupp);
        }
        mp->b_cont = allocb(allocsize, BPRI_HI);
        if (mp->b_cont == NULL) {
                rw_exit(&ipss->ipsec_alg_lock);
                freemsg(mp);
                return (B_FALSE);
        }

        mp->b_cont->b_wptr += allocsize;
        nextext = (sadb_ext_t *)(mp->b_cont->b_rptr + sizeof (*samsg));

        if (num_aalgs != 0) {

                saalg = (sadb_alg_t *)(((uint8_t *)nextext) + sizeof (*sasupp));
                ASSERT(((ulong_t)saalg & 0x7) == 0);

                numalgs_snap = 0;
                for (i = 0;
                    ((i < IPSEC_MAX_ALGS) && (numalgs_snap < num_aalgs));
                    i++) {
                        if (authalgs[i] == NULL || !ALG_VALID(authalgs[i]))
                                continue;

                        saalg->sadb_alg_id = authalgs[i]->alg_id;
                        saalg->sadb_alg_ivlen = 0;
                        saalg->sadb_alg_minbits = authalgs[i]->alg_ef_minbits;
                        saalg->sadb_alg_maxbits = authalgs[i]->alg_ef_maxbits;
                        saalg->sadb_x_alg_increment =
                            authalgs[i]->alg_increment;
                        /* For now, salt is meaningless in AH. */
                        ASSERT(authalgs[i]->alg_saltlen == 0);
                        saalg->sadb_x_alg_saltbits =
                            SADB_8TO1(authalgs[i]->alg_saltlen);
                        numalgs_snap++;
                        saalg++;
                }
                ASSERT(numalgs_snap == num_aalgs);
#ifdef DEBUG
                /*
                 * Reality check to make sure I snagged all of the
                 * algorithms.
                 */
                for (; i < IPSEC_MAX_ALGS; i++)
                        if (authalgs[i] != NULL && ALG_VALID(authalgs[i]))
                                cmn_err(CE_PANIC,
                                    "ah_register_out()!  Missed #%d.\n", i);
#endif /* DEBUG */
                nextext = (sadb_ext_t *)saalg;
        }

        rw_exit(&ipss->ipsec_alg_lock);

        if (sens_tsl != NULL) {
                sens = (sadb_sens_t *)nextext;
                sadb_sens_from_label(sens, SADB_EXT_SENSITIVITY,
                    sens_tsl, sens_len);

                nextext = (sadb_ext_t *)(((uint8_t *)sens) + sens_len);
        }

        /* Now fill the restof the SADB_REGISTER message. */

        samsg = (sadb_msg_t *)mp->b_cont->b_rptr;
        samsg->sadb_msg_version = PF_KEY_V2;
        samsg->sadb_msg_type = SADB_REGISTER;
        samsg->sadb_msg_errno = 0;
        samsg->sadb_msg_satype = SADB_SATYPE_AH;
        samsg->sadb_msg_len = SADB_8TO64(allocsize);
        samsg->sadb_msg_reserved = 0;
        /*
         * Assume caller has sufficient sequence/pid number info.  If it's one
         * from me over a new alg., I could give two hoots about sequence.
         */
        samsg->sadb_msg_seq = sequence;
        samsg->sadb_msg_pid = pid;

        if (num_aalgs != 0) {
                sasupp = (sadb_supported_t *)(samsg + 1);
                sasupp->sadb_supported_len = SADB_8TO64(
                    sizeof (*sasupp) + sizeof (*saalg) * num_aalgs);
                sasupp->sadb_supported_exttype = SADB_EXT_SUPPORTED_AUTH;
                sasupp->sadb_supported_reserved = 0;
        }

        if (ahstack->ah_pfkey_q != NULL)
                putnext(ahstack->ah_pfkey_q, mp);
        else {
                rc = B_FALSE;
                freemsg(mp);
        }

        return (rc);
}

/*
 * Invoked when the algorithm table changes. Causes SADB_REGISTER
 * messages continaining the current list of algorithms to be
 * sent up to the AH listeners.
 */
void
ipsecah_algs_changed(netstack_t *ns)
{
        ipsecah_stack_t *ahstack = ns->netstack_ipsecah;

        /*
         * Time to send a PF_KEY SADB_REGISTER message to AH listeners
         * everywhere.  (The function itself checks for NULL ah_pfkey_q.)
         */
        (void) ah_register_out(0, 0, 0, ahstack, NULL);
}

/*
 * Stub function that taskq_dispatch() invokes to take the mblk (in arg)
 * and send it into AH and IP again.
 */
static void
inbound_task(void *arg)
{
        mblk_t          *mp = (mblk_t *)arg;
        mblk_t          *async_mp;
        ip_recv_attr_t  iras;

        async_mp = mp;
        mp = async_mp->b_cont;
        async_mp->b_cont = NULL;
        if (!ip_recv_attr_from_mblk(async_mp, &iras)) {
                /* The ill or ip_stack_t disappeared on us */
                ip_drop_input("ip_recv_attr_from_mblk", mp, NULL);
                freemsg(mp);
                goto done;
        }

        ah_inbound_restart(mp, &iras);
done:
        ira_cleanup(&iras, B_TRUE);
}

/*
 * Restart ESP after the SA has been added.
 */
static void
ah_inbound_restart(mblk_t *mp, ip_recv_attr_t *ira)
{
        ah_t            *ah;
        netstack_t      *ns;
        ipsecah_stack_t *ahstack;

        ns = ira->ira_ill->ill_ipst->ips_netstack;
        ahstack = ns->netstack_ipsecah;

        ASSERT(ahstack != NULL);
        mp = ipsec_inbound_ah_sa(mp, ira, &ah);
        if (mp == NULL)
                return;

        ASSERT(ah != NULL);
        ASSERT(ira->ira_flags & IRAF_IPSEC_SECURE);
        ASSERT(ira->ira_ipsec_ah_sa != NULL);

        mp = ira->ira_ipsec_ah_sa->ipsa_input_func(mp, ah, ira);
        if (mp == NULL) {
                /*
                 * Either it failed or is pending. In the former case
                 * ipIfStatsInDiscards was increased.
                 */
                return;
        }
        ip_input_post_ipsec(mp, ira);
}

/*
 * Now that weak-key passed, actually ADD the security association, and
 * send back a reply ADD message.
 */
static int
ah_add_sa_finish(mblk_t *mp, sadb_msg_t *samsg, keysock_in_t *ksi,
    int *diagnostic, ipsecah_stack_t *ahstack)
{
        isaf_t *primary = NULL, *secondary;
        boolean_t clone = B_FALSE, is_inbound = B_FALSE;
        sadb_sa_t *assoc = (sadb_sa_t *)ksi->ks_in_extv[SADB_EXT_SA];
        ipsa_t *larval;
        ipsacq_t *acqrec;
        iacqf_t *acq_bucket;
        mblk_t *acq_msgs = NULL;
        mblk_t *lpkt;
        int rc;
        ipsa_query_t sq;
        int error;
        netstack_t      *ns = ahstack->ipsecah_netstack;
        ipsec_stack_t   *ipss = ns->netstack_ipsec;

        /*
         * Locate the appropriate table(s).
         */

        sq.spp = &ahstack->ah_sadb;
        error = sadb_form_query(ksi, IPSA_Q_SA|IPSA_Q_DST,
            IPSA_Q_SA|IPSA_Q_DST|IPSA_Q_INBOUND|IPSA_Q_OUTBOUND,
            &sq, diagnostic);
        if (error)
                return (error);

        /*
         * Use the direction flags provided by the KMD to determine
         * if the inbound or outbound table should be the primary
         * for this SA. If these flags were absent then make this
         * decision based on the addresses.
         */
        if (assoc->sadb_sa_flags & IPSA_F_INBOUND) {
                primary = sq.inbound;
                secondary = sq.outbound;
                is_inbound = B_TRUE;
                if (assoc->sadb_sa_flags & IPSA_F_OUTBOUND)
                        clone = B_TRUE;
        } else {
                if (assoc->sadb_sa_flags & IPSA_F_OUTBOUND) {
                        primary = sq.outbound;
                        secondary = sq.inbound;
                }
        }
        if (primary == NULL) {
                /*
                 * The KMD did not set a direction flag, determine which
                 * table to insert the SA into based on addresses.
                 */
                switch (ksi->ks_in_dsttype) {
                case KS_IN_ADDR_MBCAST:
                        clone = B_TRUE; /* All mcast SAs can be bidirectional */
                        assoc->sadb_sa_flags |= IPSA_F_OUTBOUND;
                        /* FALLTHRU */
                /*
                 * If the source address is either one of mine, or unspecified
                 * (which is best summed up by saying "not 'not mine'"),
                 * then the association is potentially bi-directional,
                 * in that it can be used for inbound traffic and outbound
                 * traffic.  The best example of such and SA is a multicast
                 * SA (which allows me to receive the outbound traffic).
                 */
                case KS_IN_ADDR_ME:
                        assoc->sadb_sa_flags |= IPSA_F_INBOUND;
                        primary = sq.inbound;
                        secondary = sq.outbound;
                        if (ksi->ks_in_srctype != KS_IN_ADDR_NOTME)
                                clone = B_TRUE;
                        is_inbound = B_TRUE;
                        break;

                /*
                 * If the source address literally not mine (either
                 * unspecified or not mine), then this SA may have an
                 * address that WILL be mine after some configuration.
                 * We pay the price for this by making it a bi-directional
                 * SA.
                 */
                case KS_IN_ADDR_NOTME:
                        assoc->sadb_sa_flags |= IPSA_F_OUTBOUND;
                        primary = sq.outbound;
                        secondary = sq.inbound;
                        if (ksi->ks_in_srctype != KS_IN_ADDR_ME) {
                                assoc->sadb_sa_flags |= IPSA_F_INBOUND;
                                clone = B_TRUE;
                        }
                        break;
                default:
                        *diagnostic = SADB_X_DIAGNOSTIC_BAD_DST;
                        return (EINVAL);
                }
        }

        /*
         * Find a ACQUIRE list entry if possible.  If we've added an SA that
         * suits the needs of an ACQUIRE list entry, we can eliminate the
         * ACQUIRE list entry and transmit the enqueued packets.  Use the
         * high-bit of the sequence number to queue it.  Key off destination
         * addr, and change acqrec's state.
         */

        if (samsg->sadb_msg_seq & IACQF_LOWEST_SEQ) {
                acq_bucket = &(sq.sp->sdb_acq[sq.outhash]);
                mutex_enter(&acq_bucket->iacqf_lock);
                for (acqrec = acq_bucket->iacqf_ipsacq; acqrec != NULL;
                    acqrec = acqrec->ipsacq_next) {
                        mutex_enter(&acqrec->ipsacq_lock);
                        /*
                         * Q:  I only check sequence.  Should I check dst?
                         * A: Yes, check dest because those are the packets
                         *    that are queued up.
                         */
                        if (acqrec->ipsacq_seq == samsg->sadb_msg_seq &&
                            IPSA_ARE_ADDR_EQUAL(sq.dstaddr,
                            acqrec->ipsacq_dstaddr, acqrec->ipsacq_addrfam))
                                break;
                        mutex_exit(&acqrec->ipsacq_lock);
                }
                if (acqrec != NULL) {
                        /*
                         * AHA!  I found an ACQUIRE record for this SA.
                         * Grab the msg list, and free the acquire record.
                         * I already am holding the lock for this record,
                         * so all I have to do is free it.
                         */
                        acq_msgs = acqrec->ipsacq_mp;
                        acqrec->ipsacq_mp = NULL;
                        mutex_exit(&acqrec->ipsacq_lock);
                        sadb_destroy_acquire(acqrec, ns);
                }
                mutex_exit(&acq_bucket->iacqf_lock);
        }

        /*
         * Find PF_KEY message, and see if I'm an update.  If so, find entry
         * in larval list (if there).
         */

        larval = NULL;

        if (samsg->sadb_msg_type == SADB_UPDATE) {
                mutex_enter(&sq.inbound->isaf_lock);
                larval = ipsec_getassocbyspi(sq.inbound, sq.assoc->sadb_sa_spi,
                    ALL_ZEROES_PTR, sq.dstaddr, sq.dst->sin_family);
                mutex_exit(&sq.inbound->isaf_lock);

                if ((larval == NULL) ||
                    (larval->ipsa_state != IPSA_STATE_LARVAL)) {
                        *diagnostic = SADB_X_DIAGNOSTIC_SA_NOTFOUND;
                        if (larval != NULL) {
                                IPSA_REFRELE(larval);
                        }
                        ah0dbg(("Larval update, but larval disappeared.\n"));
                        return (ESRCH);
                } /* Else sadb_common_add unlinks it for me! */
        }

        if (larval != NULL) {
                /*
                 * Hold again, because sadb_common_add() consumes a reference,
                 * and we don't want to clear_lpkt() without a reference.
                 */
                IPSA_REFHOLD(larval);
        }

        rc = sadb_common_add(ahstack->ah_pfkey_q, mp,
            samsg, ksi, primary, secondary, larval, clone, is_inbound,
            diagnostic, ns, &ahstack->ah_sadb);

        if (larval != NULL) {
                if (rc == 0) {
                        lpkt = sadb_clear_lpkt(larval);
                        if (lpkt != NULL) {
                                rc = taskq_dispatch(ah_taskq, inbound_task,
                                    lpkt, TQ_NOSLEEP) == TASKQID_INVALID;
                        }
                }
                IPSA_REFRELE(larval);
        }

        /*
         * How much more stack will I create with all of these
         * ah_outbound_*() calls?
         */

        /* Handle the packets queued waiting for the SA */
        while (acq_msgs != NULL) {
                mblk_t          *asyncmp;
                mblk_t          *data_mp;
                ip_xmit_attr_t  ixas;
                ill_t           *ill;

                asyncmp = acq_msgs;
                acq_msgs = acq_msgs->b_next;
                asyncmp->b_next = NULL;

                /*
                 * Extract the ip_xmit_attr_t from the first mblk.
                 * Verifies that the netstack and ill is still around; could
                 * have vanished while iked was doing its work.
                 * On succesful return we have a nce_t and the ill/ipst can't
                 * disappear until we do the nce_refrele in ixa_cleanup.
                 */
                data_mp = asyncmp->b_cont;
                asyncmp->b_cont = NULL;
                if (!ip_xmit_attr_from_mblk(asyncmp, &ixas)) {
                        AH_BUMP_STAT(ahstack, out_discards);
                        ip_drop_packet(data_mp, B_FALSE, NULL,
                            DROPPER(ipss, ipds_sadb_acquire_timeout),
                            &ahstack->ah_dropper);
                } else if (rc != 0) {
                        ill = ixas.ixa_nce->nce_ill;
                        AH_BUMP_STAT(ahstack, out_discards);
                        ip_drop_packet(data_mp, B_FALSE, ill,
                            DROPPER(ipss, ipds_sadb_acquire_timeout),
                            &ahstack->ah_dropper);
                        BUMP_MIB(ill->ill_ip_mib, ipIfStatsOutDiscards);
                } else {
                        ah_outbound_finish(data_mp, &ixas);
                }
                ixa_cleanup(&ixas);
        }

        return (rc);
}


/*
 * Process one of the queued messages (from ipsacq_mp) once the SA
 * has been added.
 */
static void
ah_outbound_finish(mblk_t *data_mp, ip_xmit_attr_t *ixa)
{
        netstack_t      *ns = ixa->ixa_ipst->ips_netstack;
        ipsecah_stack_t *ahstack = ns->netstack_ipsecah;
        ipsec_stack_t   *ipss = ns->netstack_ipsec;
        ill_t           *ill = ixa->ixa_nce->nce_ill;

        if (!ipsec_outbound_sa(data_mp, ixa, IPPROTO_AH)) {
                AH_BUMP_STAT(ahstack, out_discards);
                ip_drop_packet(data_mp, B_FALSE, ill,
                    DROPPER(ipss, ipds_sadb_acquire_timeout),
                    &ahstack->ah_dropper);
                BUMP_MIB(ill->ill_ip_mib, ipIfStatsOutDiscards);
                return;
        }

        data_mp = ah_outbound(data_mp, ixa);
        if (data_mp == NULL)
                return;

        (void) ip_output_post_ipsec(data_mp, ixa);
}

/*
 * Add new AH security association.  This may become a generic AH/ESP
 * routine eventually.
 */
static int
ah_add_sa(mblk_t *mp, keysock_in_t *ksi, int *diagnostic, netstack_t *ns)
{
        sadb_sa_t *assoc = (sadb_sa_t *)ksi->ks_in_extv[SADB_EXT_SA];
        sadb_address_t *srcext =
            (sadb_address_t *)ksi->ks_in_extv[SADB_EXT_ADDRESS_SRC];
        sadb_address_t *dstext =
            (sadb_address_t *)ksi->ks_in_extv[SADB_EXT_ADDRESS_DST];
        sadb_address_t *isrcext =
            (sadb_address_t *)ksi->ks_in_extv[SADB_X_EXT_ADDRESS_INNER_SRC];
        sadb_address_t *idstext =
            (sadb_address_t *)ksi->ks_in_extv[SADB_X_EXT_ADDRESS_INNER_DST];
        sadb_key_t *key = (sadb_key_t *)ksi->ks_in_extv[SADB_EXT_KEY_AUTH];
        struct sockaddr_in *src, *dst;
        /* We don't need sockaddr_in6 for now. */
        sadb_lifetime_t *soft =
            (sadb_lifetime_t *)ksi->ks_in_extv[SADB_EXT_LIFETIME_SOFT];
        sadb_lifetime_t *hard =
            (sadb_lifetime_t *)ksi->ks_in_extv[SADB_EXT_LIFETIME_HARD];
        sadb_lifetime_t *idle =
            (sadb_lifetime_t *)ksi->ks_in_extv[SADB_X_EXT_LIFETIME_IDLE];
        ipsec_alginfo_t *aalg;
        ipsecah_stack_t *ahstack = ns->netstack_ipsecah;
        ipsec_stack_t   *ipss = ns->netstack_ipsec;

        /* I need certain extensions present for an ADD message. */
        if (srcext == NULL) {
                *diagnostic = SADB_X_DIAGNOSTIC_MISSING_SRC;
                return (EINVAL);
        }
        if (dstext == NULL) {
                *diagnostic = SADB_X_DIAGNOSTIC_MISSING_DST;
                return (EINVAL);
        }
        if (isrcext == NULL && idstext != NULL) {
                *diagnostic = SADB_X_DIAGNOSTIC_MISSING_INNER_SRC;
                return (EINVAL);
        }
        if (isrcext != NULL && idstext == NULL) {
                *diagnostic = SADB_X_DIAGNOSTIC_MISSING_INNER_DST;
                return (EINVAL);
        }
        if (assoc == NULL) {
                *diagnostic = SADB_X_DIAGNOSTIC_MISSING_SA;
                return (EINVAL);
        }
        if (key == NULL) {
                *diagnostic = SADB_X_DIAGNOSTIC_MISSING_AKEY;
                return (EINVAL);
        }

        src = (struct sockaddr_in *)(srcext + 1);
        dst = (struct sockaddr_in *)(dstext + 1);

        /* Sundry ADD-specific reality checks. */
        /* XXX STATS : Logging/stats here? */

        if ((assoc->sadb_sa_state != SADB_SASTATE_MATURE) &&
            (assoc->sadb_sa_state != SADB_X_SASTATE_ACTIVE_ELSEWHERE)) {
                *diagnostic = SADB_X_DIAGNOSTIC_BAD_SASTATE;
                return (EINVAL);
        }
        if (assoc->sadb_sa_encrypt != SADB_EALG_NONE) {
                *diagnostic = SADB_X_DIAGNOSTIC_ENCR_NOTSUPP;
                return (EINVAL);
        }
        if (assoc->sadb_sa_flags & ~ahstack->ah_sadb.s_addflags) {
                *diagnostic = SADB_X_DIAGNOSTIC_BAD_SAFLAGS;
                return (EINVAL);
        }
        if ((*diagnostic = sadb_hardsoftchk(hard, soft, idle)) != 0)
                return (EINVAL);

        ASSERT(src->sin_family == dst->sin_family);

        /* Stuff I don't support, for now.  XXX Diagnostic? */
        if (ksi->ks_in_extv[SADB_EXT_LIFETIME_CURRENT] != NULL)
                return (EOPNOTSUPP);

        if (ksi->ks_in_extv[SADB_EXT_SENSITIVITY] != NULL) {
                if (!is_system_labeled())
                        return (EOPNOTSUPP);
        }

        if (ksi->ks_in_extv[SADB_X_EXT_OUTER_SENS] != NULL) {
                if (!is_system_labeled())
                        return (EOPNOTSUPP);
        }
        /*
         * XXX Policy : I'm not checking identities at this time, but
         * if I did, I'd do them here, before I sent the weak key
         * check up to the algorithm.
         */

        /* verify that there is a mapping for the specified algorithm */
        rw_enter(&ipss->ipsec_alg_lock, RW_READER);
        aalg = ipss->ipsec_alglists[IPSEC_ALG_AUTH][assoc->sadb_sa_auth];
        if (aalg == NULL || !ALG_VALID(aalg)) {
                rw_exit(&ipss->ipsec_alg_lock);
                ah1dbg(ahstack, ("Couldn't find auth alg #%d.\n",
                    assoc->sadb_sa_auth));
                *diagnostic = SADB_X_DIAGNOSTIC_BAD_AALG;
                return (EINVAL);
        }
        ASSERT(aalg->alg_mech_type != CRYPTO_MECHANISM_INVALID);

        /* sanity check key sizes */
        if (!ipsec_valid_key_size(key->sadb_key_bits, aalg)) {
                rw_exit(&ipss->ipsec_alg_lock);
                *diagnostic = SADB_X_DIAGNOSTIC_BAD_AKEYBITS;
                return (EINVAL);
        }

        /* check key and fix parity if needed */
        if (ipsec_check_key(aalg->alg_mech_type, key, B_TRUE,
            diagnostic) != 0) {
                rw_exit(&ipss->ipsec_alg_lock);
                return (EINVAL);
        }

        rw_exit(&ipss->ipsec_alg_lock);

        return (ah_add_sa_finish(mp, (sadb_msg_t *)mp->b_cont->b_rptr, ksi,
            diagnostic, ahstack));
}

/* Refactor me */
/*
 * Update a security association.  Updates come in two varieties.  The first
 * is an update of lifetimes on a non-larval SA.  The second is an update of
 * a larval SA, which ends up looking a lot more like an add.
 */
static int
ah_update_sa(mblk_t *mp, keysock_in_t *ksi, int *diagnostic,
    ipsecah_stack_t *ahstack, uint8_t sadb_msg_type)
{
        sadb_sa_t *assoc = (sadb_sa_t *)ksi->ks_in_extv[SADB_EXT_SA];
        sadb_address_t *dstext =
            (sadb_address_t *)ksi->ks_in_extv[SADB_EXT_ADDRESS_DST];
        mblk_t  *buf_pkt;
        int rcode;

        if (dstext == NULL) {
                *diagnostic = SADB_X_DIAGNOSTIC_MISSING_DST;
                return (EINVAL);
        }

        rcode = sadb_update_sa(mp, ksi, &buf_pkt, &ahstack->ah_sadb,
            diagnostic, ahstack->ah_pfkey_q, ah_add_sa,
            ahstack->ipsecah_netstack, sadb_msg_type);

        if ((assoc->sadb_sa_state != SADB_X_SASTATE_ACTIVE) ||
            (rcode != 0)) {
                return (rcode);
        }

        HANDLE_BUF_PKT(ah_taskq, ahstack->ipsecah_netstack->netstack_ipsec,
            ahstack->ah_dropper, buf_pkt);

        return (rcode);
}

/* Refactor me */
/*
 * Delete a security association.  This is REALLY likely to be code common to
 * both AH and ESP.  Find the association, then unlink it.
 */
static int
ah_del_sa(mblk_t *mp, keysock_in_t *ksi, int *diagnostic,
    ipsecah_stack_t *ahstack, uint8_t sadb_msg_type)
{
        sadb_sa_t *assoc = (sadb_sa_t *)ksi->ks_in_extv[SADB_EXT_SA];
        sadb_address_t *dstext =
            (sadb_address_t *)ksi->ks_in_extv[SADB_EXT_ADDRESS_DST];
        sadb_address_t *srcext =
            (sadb_address_t *)ksi->ks_in_extv[SADB_EXT_ADDRESS_SRC];
        struct sockaddr_in *sin;

        if (assoc == NULL) {
                if (dstext != NULL)
                        sin = (struct sockaddr_in *)(dstext + 1);
                else if (srcext != NULL)
                        sin = (struct sockaddr_in *)(srcext + 1);
                else {
                        *diagnostic = SADB_X_DIAGNOSTIC_MISSING_SA;
                        return (EINVAL);
                }
                return (sadb_purge_sa(mp, ksi,
                    (sin->sin_family == AF_INET6) ? &ahstack->ah_sadb.s_v6 :
                    &ahstack->ah_sadb.s_v4, diagnostic, ahstack->ah_pfkey_q));
        }

        return (sadb_delget_sa(mp, ksi, &ahstack->ah_sadb, diagnostic,
            ahstack->ah_pfkey_q, sadb_msg_type));
}

/* Refactor me */
/*
 * Convert the entire contents of all of AH's SA tables into PF_KEY SADB_DUMP
 * messages.
 */
static void
ah_dump(mblk_t *mp, keysock_in_t *ksi, ipsecah_stack_t *ahstack)
{
        int error;
        sadb_msg_t *samsg;

        /*
         * Dump each fanout, bailing if error is non-zero.
         */

        error = sadb_dump(ahstack->ah_pfkey_q, mp, ksi, &ahstack->ah_sadb.s_v4);
        if (error != 0)
                goto bail;

        error = sadb_dump(ahstack->ah_pfkey_q, mp, ksi, &ahstack->ah_sadb.s_v6);
bail:
        ASSERT(mp->b_cont != NULL);
        samsg = (sadb_msg_t *)mp->b_cont->b_rptr;
        samsg->sadb_msg_errno = (uint8_t)error;
        sadb_pfkey_echo(ahstack->ah_pfkey_q, mp,
            (sadb_msg_t *)mp->b_cont->b_rptr, ksi, NULL);
}

/*
 * First-cut reality check for an inbound PF_KEY message.
 */
static boolean_t
ah_pfkey_reality_failures(mblk_t *mp, keysock_in_t *ksi,
    ipsecah_stack_t *ahstack)
{
        int diagnostic;

        if (mp->b_cont == NULL) {
                freemsg(mp);
                return (B_TRUE);
        }

        if (ksi->ks_in_extv[SADB_EXT_KEY_ENCRYPT] != NULL) {
                diagnostic = SADB_X_DIAGNOSTIC_EKEY_PRESENT;
                goto badmsg;
        }
        if (ksi->ks_in_extv[SADB_EXT_PROPOSAL] != NULL) {
                diagnostic = SADB_X_DIAGNOSTIC_PROP_PRESENT;
                goto badmsg;
        }
        if (ksi->ks_in_extv[SADB_EXT_SUPPORTED_AUTH] != NULL ||
            ksi->ks_in_extv[SADB_EXT_SUPPORTED_ENCRYPT] != NULL) {
                diagnostic = SADB_X_DIAGNOSTIC_SUPP_PRESENT;
                goto badmsg;
        }
        return (B_FALSE);       /* False ==> no failures */

badmsg:
        sadb_pfkey_error(ahstack->ah_pfkey_q, mp, EINVAL,
            diagnostic, ksi->ks_in_serial);
        return (B_TRUE);        /* True ==> failures */
}

/*
 * AH parsing of PF_KEY messages.  Keysock did most of the really silly
 * error cases.  What I receive is a fully-formed, syntactically legal
 * PF_KEY message.  I then need to check semantics...
 *
 * This code may become common to AH and ESP.  Stay tuned.
 *
 * I also make the assumption that db_ref's are cool.  If this assumption
 * is wrong, this means that someone other than keysock or me has been
 * mucking with PF_KEY messages.
 */
static void
ah_parse_pfkey(mblk_t *mp, ipsecah_stack_t *ahstack)
{
        mblk_t *msg = mp->b_cont;
        sadb_msg_t *samsg;
        keysock_in_t *ksi;
        int error;
        int diagnostic = SADB_X_DIAGNOSTIC_NONE;

        ASSERT(msg != NULL);

        samsg = (sadb_msg_t *)msg->b_rptr;
        ksi = (keysock_in_t *)mp->b_rptr;

        /*
         * If applicable, convert unspecified AF_INET6 to unspecified
         * AF_INET.
         */
        if (!sadb_addrfix(ksi, ahstack->ah_pfkey_q, mp,
            ahstack->ipsecah_netstack) ||
            ah_pfkey_reality_failures(mp, ksi, ahstack)) {
                return;
        }

        switch (samsg->sadb_msg_type) {
        case SADB_ADD:
                error = ah_add_sa(mp, ksi, &diagnostic,
                    ahstack->ipsecah_netstack);
                if (error != 0) {
                        sadb_pfkey_error(ahstack->ah_pfkey_q, mp, error,
                            diagnostic, ksi->ks_in_serial);
                }
                /* else ah_add_sa() took care of things. */
                break;
        case SADB_DELETE:
        case SADB_X_DELPAIR:
        case SADB_X_DELPAIR_STATE:
                error = ah_del_sa(mp, ksi, &diagnostic, ahstack,
                    samsg->sadb_msg_type);
                if (error != 0) {
                        sadb_pfkey_error(ahstack->ah_pfkey_q, mp, error,
                            diagnostic, ksi->ks_in_serial);
                }
                /* Else ah_del_sa() took care of things. */
                break;
        case SADB_GET:
                error = sadb_delget_sa(mp, ksi, &ahstack->ah_sadb, &diagnostic,
                    ahstack->ah_pfkey_q, samsg->sadb_msg_type);
                if (error != 0) {
                        sadb_pfkey_error(ahstack->ah_pfkey_q, mp, error,
                            diagnostic, ksi->ks_in_serial);
                }
                /* Else sadb_get_sa() took care of things. */
                break;
        case SADB_FLUSH:
                sadbp_flush(&ahstack->ah_sadb, ahstack->ipsecah_netstack);
                sadb_pfkey_echo(ahstack->ah_pfkey_q, mp, samsg, ksi, NULL);
                break;
        case SADB_REGISTER:
                /*
                 * Hmmm, let's do it!  Check for extensions (there should
                 * be none), extract the fields, call ah_register_out(),
                 * then either free or report an error.
                 *
                 * Keysock takes care of the PF_KEY bookkeeping for this.
                 */
                if (ah_register_out(samsg->sadb_msg_seq, samsg->sadb_msg_pid,
                    ksi->ks_in_serial, ahstack, msg_getcred(mp, NULL))) {
                        freemsg(mp);
                } else {
                        /*
                         * Only way this path hits is if there is a memory
                         * failure.  It will not return B_FALSE because of
                         * lack of ah_pfkey_q if I am in wput().
                         */
                        sadb_pfkey_error(ahstack->ah_pfkey_q, mp, ENOMEM,
                            diagnostic, ksi->ks_in_serial);
                }
                break;
        case SADB_UPDATE:
        case SADB_X_UPDATEPAIR:
                /*
                 * Find a larval, if not there, find a full one and get
                 * strict.
                 */
                error = ah_update_sa(mp, ksi, &diagnostic, ahstack,
                    samsg->sadb_msg_type);
                if (error != 0) {
                        sadb_pfkey_error(ahstack->ah_pfkey_q, mp, error,
                            diagnostic, ksi->ks_in_serial);
                }
                /* else ah_update_sa() took care of things. */
                break;
        case SADB_GETSPI:
                /*
                 * Reserve a new larval entry.
                 */
                ah_getspi(mp, ksi, ahstack);
                break;
        case SADB_ACQUIRE:
                /*
                 * Find larval and/or ACQUIRE record and kill it (them), I'm
                 * most likely an error.  Inbound ACQUIRE messages should only
                 * have the base header.
                 */
                sadb_in_acquire(samsg, &ahstack->ah_sadb, ahstack->ah_pfkey_q,
                    ahstack->ipsecah_netstack);
                freemsg(mp);
                break;
        case SADB_DUMP:
                /*
                 * Dump all entries.
                 */
                ah_dump(mp, ksi, ahstack);
                /* ah_dump will take care of the return message, etc. */
                break;
        case SADB_EXPIRE:
                /* Should never reach me. */
                sadb_pfkey_error(ahstack->ah_pfkey_q, mp, EOPNOTSUPP,
                    diagnostic, ksi->ks_in_serial);
                break;
        default:
                sadb_pfkey_error(ahstack->ah_pfkey_q, mp, EINVAL,
                    SADB_X_DIAGNOSTIC_UNKNOWN_MSG, ksi->ks_in_serial);
                break;
        }
}

/*
 * Handle case where PF_KEY says it can't find a keysock for one of my
 * ACQUIRE messages.
 */
static void
ah_keysock_no_socket(mblk_t *mp, ipsecah_stack_t *ahstack)
{
        sadb_msg_t *samsg;
        keysock_out_err_t *kse = (keysock_out_err_t *)mp->b_rptr;

        if (mp->b_cont == NULL) {
                freemsg(mp);
                return;
        }
        samsg = (sadb_msg_t *)mp->b_cont->b_rptr;

        /*
         * If keysock can't find any registered, delete the acquire record
         * immediately, and handle errors.
         */
        if (samsg->sadb_msg_type == SADB_ACQUIRE) {
                samsg->sadb_msg_errno = kse->ks_err_errno;
                samsg->sadb_msg_len = SADB_8TO64(sizeof (*samsg));
                /*
                 * Use the write-side of the ah_pfkey_q
                 */
                sadb_in_acquire(samsg, &ahstack->ah_sadb,
                    WR(ahstack->ah_pfkey_q), ahstack->ipsecah_netstack);
        }

        freemsg(mp);
}

/*
 * AH module read put routine.
 */
static int
ipsecah_rput(queue_t *q, mblk_t *mp)
{
        putnext(q, mp);
        return (0);
}

/*
 * AH module write put routine.
 */
static int
ipsecah_wput(queue_t *q, mblk_t *mp)
{
        ipsec_info_t *ii;
        struct iocblk *iocp;
        ipsecah_stack_t *ahstack = (ipsecah_stack_t *)q->q_ptr;

        ah3dbg(ahstack, ("In ah_wput().\n"));

        /* NOTE:  Each case must take care of freeing or passing mp. */
        switch (mp->b_datap->db_type) {
        case M_CTL:
                if ((mp->b_wptr - mp->b_rptr) < sizeof (ipsec_info_t)) {
                        /* Not big enough message. */
                        freemsg(mp);
                        break;
                }
                ii = (ipsec_info_t *)mp->b_rptr;

                switch (ii->ipsec_info_type) {
                case KEYSOCK_OUT_ERR:
                        ah1dbg(ahstack, ("Got KEYSOCK_OUT_ERR message.\n"));
                        ah_keysock_no_socket(mp, ahstack);
                        break;
                case KEYSOCK_IN:
                        AH_BUMP_STAT(ahstack, keysock_in);
                        ah3dbg(ahstack, ("Got KEYSOCK_IN message.\n"));

                        /* Parse the message. */
                        ah_parse_pfkey(mp, ahstack);
                        break;
                case KEYSOCK_HELLO:
                        sadb_keysock_hello(&ahstack->ah_pfkey_q, q, mp,
                            ah_ager, (void *)ahstack, &ahstack->ah_event,
                            SADB_SATYPE_AH);
                        break;
                default:
                        ah1dbg(ahstack, ("Got M_CTL from above of 0x%x.\n",
                            ii->ipsec_info_type));
                        freemsg(mp);
                        break;
                }
                break;
        case M_IOCTL:
                iocp = (struct iocblk *)mp->b_rptr;
                switch (iocp->ioc_cmd) {
                case ND_SET:
                case ND_GET:
                        if (nd_getset(q, ahstack->ipsecah_g_nd, mp)) {
                                qreply(q, mp);
                                return (0);
                        } else {
                                iocp->ioc_error = ENOENT;
                        }
                        /* FALLTHRU */
                default:
                        /* We really don't support any other ioctls, do we? */

                        /* Return EINVAL */
                        if (iocp->ioc_error != ENOENT)
                                iocp->ioc_error = EINVAL;
                        iocp->ioc_count = 0;
                        mp->b_datap->db_type = M_IOCACK;
                        qreply(q, mp);
                        return (0);
                }
        default:
                ah3dbg(ahstack,
                    ("Got default message, type %d, passing to IP.\n",
                    mp->b_datap->db_type));
                putnext(q, mp);
        }
        return (0);
}

/* Refactor me */
/*
 * Updating use times can be tricky business if the ipsa_haspeer flag is
 * set.  This function is called once in an SA's lifetime.
 *
 * Caller has to REFRELE "assoc" which is passed in.  This function has
 * to REFRELE any peer SA that is obtained.
 */
static void
ah_set_usetime(ipsa_t *assoc, boolean_t inbound)
{
        ipsa_t *inassoc, *outassoc;
        isaf_t *bucket;
        sadb_t *sp;
        int outhash;
        boolean_t isv6;
        netstack_t      *ns = assoc->ipsa_netstack;
        ipsecah_stack_t *ahstack = ns->netstack_ipsecah;

        /* No peer?  No problem! */
        if (!assoc->ipsa_haspeer) {
                sadb_set_usetime(assoc);
                return;
        }

        /*
         * Otherwise, we want to grab both the original assoc and its peer.
         * There might be a race for this, but if it's a real race, the times
         * will be out-of-synch by at most a second, and since our time
         * granularity is a second, this won't be a problem.
         *
         * If we need tight synchronization on the peer SA, then we need to
         * reconsider.
         */

        /* Use address family to select IPv6/IPv4 */
        isv6 = (assoc->ipsa_addrfam == AF_INET6);
        if (isv6) {
                sp = &ahstack->ah_sadb.s_v6;
        } else {
                sp = &ahstack->ah_sadb.s_v4;
                ASSERT(assoc->ipsa_addrfam == AF_INET);
        }
        if (inbound) {
                inassoc = assoc;
                if (isv6)
                        outhash = OUTBOUND_HASH_V6(sp,
                            *((in6_addr_t *)&inassoc->ipsa_dstaddr));
                else
                        outhash = OUTBOUND_HASH_V4(sp,
                            *((ipaddr_t *)&inassoc->ipsa_dstaddr));
                bucket = &sp->sdb_of[outhash];

                mutex_enter(&bucket->isaf_lock);
                outassoc = ipsec_getassocbyspi(bucket, inassoc->ipsa_spi,
                    inassoc->ipsa_srcaddr, inassoc->ipsa_dstaddr,
                    inassoc->ipsa_addrfam);
                mutex_exit(&bucket->isaf_lock);
                if (outassoc == NULL) {
                        /* Q: Do we wish to set haspeer == B_FALSE? */
                        ah0dbg(("ah_set_usetime: "
                            "can't find peer for inbound.\n"));
                        sadb_set_usetime(inassoc);
                        return;
                }
        } else {
                outassoc = assoc;
                bucket = INBOUND_BUCKET(sp, outassoc->ipsa_spi);
                mutex_enter(&bucket->isaf_lock);
                inassoc = ipsec_getassocbyspi(bucket, outassoc->ipsa_spi,
                    outassoc->ipsa_srcaddr, outassoc->ipsa_dstaddr,
                    outassoc->ipsa_addrfam);
                mutex_exit(&bucket->isaf_lock);
                if (inassoc == NULL) {
                        /* Q: Do we wish to set haspeer == B_FALSE? */
                        ah0dbg(("ah_set_usetime: "
                            "can't find peer for outbound.\n"));
                        sadb_set_usetime(outassoc);
                        return;
                }
        }

        /* Update usetime on both. */
        sadb_set_usetime(inassoc);
        sadb_set_usetime(outassoc);

        /*
         * REFRELE any peer SA.
         *
         * Because of the multi-line macro nature of IPSA_REFRELE, keep
         * them in { }.
         */
        if (inbound) {
                IPSA_REFRELE(outassoc);
        } else {
                IPSA_REFRELE(inassoc);
        }
}

/* Refactor me */
/*
 * Add a number of bytes to what the SA has protected so far.  Return
 * B_TRUE if the SA can still protect that many bytes.
 *
 * Caller must REFRELE the passed-in assoc.  This function must REFRELE
 * any obtained peer SA.
 */
static boolean_t
ah_age_bytes(ipsa_t *assoc, uint64_t bytes, boolean_t inbound)
{
        ipsa_t *inassoc, *outassoc;
        isaf_t *bucket;
        boolean_t inrc, outrc, isv6;
        sadb_t *sp;
        int outhash;
        netstack_t      *ns = assoc->ipsa_netstack;
        ipsecah_stack_t *ahstack = ns->netstack_ipsecah;

        /* No peer?  No problem! */
        if (!assoc->ipsa_haspeer) {
                return (sadb_age_bytes(ahstack->ah_pfkey_q, assoc, bytes,
                    B_TRUE));
        }

        /*
         * Otherwise, we want to grab both the original assoc and its peer.
         * There might be a race for this, but if it's a real race, two
         * expire messages may occur.  We limit this by only sending the
         * expire message on one of the peers, we'll pick the inbound
         * arbitrarily.
         *
         * If we need tight synchronization on the peer SA, then we need to
         * reconsider.
         */

        /* Pick v4/v6 bucket based on addrfam. */
        isv6 = (assoc->ipsa_addrfam == AF_INET6);
        if (isv6) {
                sp = &ahstack->ah_sadb.s_v6;
        } else {
                sp = &ahstack->ah_sadb.s_v4;
                ASSERT(assoc->ipsa_addrfam == AF_INET);
        }
        if (inbound) {
                inassoc = assoc;
                if (isv6)
                        outhash = OUTBOUND_HASH_V6(sp,
                            *((in6_addr_t *)&inassoc->ipsa_dstaddr));
                else
                        outhash = OUTBOUND_HASH_V4(sp,
                            *((ipaddr_t *)&inassoc->ipsa_dstaddr));
                bucket = &sp->sdb_of[outhash];
                mutex_enter(&bucket->isaf_lock);
                outassoc = ipsec_getassocbyspi(bucket, inassoc->ipsa_spi,
                    inassoc->ipsa_srcaddr, inassoc->ipsa_dstaddr,
                    inassoc->ipsa_addrfam);
                mutex_exit(&bucket->isaf_lock);
                if (outassoc == NULL) {
                        /* Q: Do we wish to set haspeer == B_FALSE? */
                        ah0dbg(("ah_age_bytes: "
                            "can't find peer for inbound.\n"));
                        return (sadb_age_bytes(ahstack->ah_pfkey_q, inassoc,
                            bytes, B_TRUE));
                }
        } else {
                outassoc = assoc;
                bucket = INBOUND_BUCKET(sp, outassoc->ipsa_spi);
                mutex_enter(&bucket->isaf_lock);
                inassoc = ipsec_getassocbyspi(bucket, outassoc->ipsa_spi,
                    outassoc->ipsa_srcaddr, outassoc->ipsa_dstaddr,
                    outassoc->ipsa_addrfam);
                mutex_exit(&bucket->isaf_lock);
                if (inassoc == NULL) {
                        /* Q: Do we wish to set haspeer == B_FALSE? */
                        ah0dbg(("ah_age_bytes: "
                            "can't find peer for outbound.\n"));
                        return (sadb_age_bytes(ahstack->ah_pfkey_q, outassoc,
                            bytes, B_TRUE));
                }
        }

        inrc = sadb_age_bytes(ahstack->ah_pfkey_q, inassoc, bytes, B_TRUE);
        outrc = sadb_age_bytes(ahstack->ah_pfkey_q, outassoc, bytes, B_FALSE);

        /*
         * REFRELE any peer SA.
         *
         * Because of the multi-line macro nature of IPSA_REFRELE, keep
         * them in { }.
         */
        if (inbound) {
                IPSA_REFRELE(outassoc);
        } else {
                IPSA_REFRELE(inassoc);
        }

        return (inrc && outrc);
}

/* Refactor me */
/*
 * Handle the SADB_GETSPI message.  Create a larval SA.
 */
static void
ah_getspi(mblk_t *mp, keysock_in_t *ksi, ipsecah_stack_t *ahstack)
{
        ipsa_t *newbie, *target;
        isaf_t *outbound, *inbound;
        int rc, diagnostic;
        sadb_sa_t *assoc;
        keysock_out_t *kso;
        uint32_t newspi;

        /*
         * Randomly generate a proposed SPI value.
         */
        if (cl_inet_getspi != NULL) {
                cl_inet_getspi(ahstack->ipsecah_netstack->netstack_stackid,
                    IPPROTO_AH, (uint8_t *)&newspi, sizeof (uint32_t), NULL);
        } else {
                (void) random_get_pseudo_bytes((uint8_t *)&newspi,
                    sizeof (uint32_t));
        }
        newbie = sadb_getspi(ksi, newspi, &diagnostic,
            ahstack->ipsecah_netstack, IPPROTO_AH);

        if (newbie == NULL) {
                sadb_pfkey_error(ahstack->ah_pfkey_q, mp, ENOMEM, diagnostic,
                    ksi->ks_in_serial);
                return;
        } else if (newbie == (ipsa_t *)-1) {
                sadb_pfkey_error(ahstack->ah_pfkey_q, mp, EINVAL, diagnostic,
                    ksi->ks_in_serial);
                return;
        }

        /*
         * XXX - We may randomly collide.  We really should recover from this.
         *       Unfortunately, that could require spending way-too-much-time
         *       in here.  For now, let the user retry.
         */

        if (newbie->ipsa_addrfam == AF_INET6) {
                outbound = OUTBOUND_BUCKET_V6(&ahstack->ah_sadb.s_v6,
                    *(uint32_t *)(newbie->ipsa_dstaddr));
                inbound = INBOUND_BUCKET(&ahstack->ah_sadb.s_v6,
                    newbie->ipsa_spi);
        } else {
                outbound = OUTBOUND_BUCKET_V4(&ahstack->ah_sadb.s_v4,
                    *(uint32_t *)(newbie->ipsa_dstaddr));
                inbound = INBOUND_BUCKET(&ahstack->ah_sadb.s_v4,
                    newbie->ipsa_spi);
        }

        mutex_enter(&outbound->isaf_lock);
        mutex_enter(&inbound->isaf_lock);

        /*
         * Check for collisions (i.e. did sadb_getspi() return with something
         * that already exists?).
         *
         * Try outbound first.  Even though SADB_GETSPI is traditionally
         * for inbound SAs, you never know what a user might do.
         */
        target = ipsec_getassocbyspi(outbound, newbie->ipsa_spi,
            newbie->ipsa_srcaddr, newbie->ipsa_dstaddr, newbie->ipsa_addrfam);
        if (target == NULL) {
                target = ipsec_getassocbyspi(inbound, newbie->ipsa_spi,
                    newbie->ipsa_srcaddr, newbie->ipsa_dstaddr,
                    newbie->ipsa_addrfam);
        }

        /*
         * I don't have collisions elsewhere!
         * (Nor will I because I'm still holding inbound/outbound locks.)
         */

        if (target != NULL) {
                rc = EEXIST;
                IPSA_REFRELE(target);
        } else {
                /*
                 * sadb_insertassoc() also checks for collisions, so
                 * if there's a colliding larval entry, rc will be set
                 * to EEXIST.
                 */
                rc = sadb_insertassoc(newbie, inbound);
                newbie->ipsa_hardexpiretime = gethrestime_sec();
                newbie->ipsa_hardexpiretime += ahstack->ipsecah_larval_timeout;
        }

        /*
         * Can exit outbound mutex.  Hold inbound until we're done with
         * newbie.
         */
        mutex_exit(&outbound->isaf_lock);

        if (rc != 0) {
                mutex_exit(&inbound->isaf_lock);
                IPSA_REFRELE(newbie);
                sadb_pfkey_error(ahstack->ah_pfkey_q, mp, rc,
                    SADB_X_DIAGNOSTIC_NONE, ksi->ks_in_serial);
                return;
        }

        /* Can write here because I'm still holding the bucket lock. */
        newbie->ipsa_type = SADB_SATYPE_AH;

        /*
         * Construct successful return message.  We have one thing going
         * for us in PF_KEY v2.  That's the fact that
         *      sizeof (sadb_spirange_t) == sizeof (sadb_sa_t)
         */
        assoc = (sadb_sa_t *)ksi->ks_in_extv[SADB_EXT_SPIRANGE];
        assoc->sadb_sa_exttype = SADB_EXT_SA;
        assoc->sadb_sa_spi = newbie->ipsa_spi;
        *((uint64_t *)(&assoc->sadb_sa_replay)) = 0;
        mutex_exit(&inbound->isaf_lock);

        /* Convert KEYSOCK_IN to KEYSOCK_OUT. */
        kso = (keysock_out_t *)ksi;
        kso->ks_out_len = sizeof (*kso);
        kso->ks_out_serial = ksi->ks_in_serial;
        kso->ks_out_type = KEYSOCK_OUT;

        /*
         * Can safely putnext() to ah_pfkey_q, because this is a turnaround
         * from the ah_pfkey_q.
         */
        putnext(ahstack->ah_pfkey_q, mp);
}

/*
 * IPv6 sends up the ICMP errors for validation and the removal of the AH
 * header.
 * If succesful, the mp has been modified to not include the AH header so
 * that the caller can fanout to the ULP's icmp error handler.
 */
static mblk_t *
ah_icmp_error_v6(mblk_t *mp, ip_recv_attr_t *ira, ipsecah_stack_t *ahstack)
{
        ip6_t *ip6h, *oip6h;
        uint16_t hdr_length, ah_length;
        uint8_t *nexthdrp;
        ah_t *ah;
        icmp6_t *icmp6;
        isaf_t *isaf;
        ipsa_t *assoc;
        uint8_t *post_ah_ptr;
        ipsec_stack_t   *ipss = ahstack->ipsecah_netstack->netstack_ipsec;

        /*
         * Eat the cost of a pullupmsg() for now.  It makes the rest of this
         * code far less convoluted.
         */
        if (!pullupmsg(mp, -1) ||
            !ip_hdr_length_nexthdr_v6(mp, (ip6_t *)mp->b_rptr, &hdr_length,
            &nexthdrp) ||
            mp->b_rptr + hdr_length + sizeof (icmp6_t) + sizeof (ip6_t) +
            sizeof (ah_t) > mp->b_wptr) {
                IP_AH_BUMP_STAT(ipss, in_discards);
                ip_drop_packet(mp, B_TRUE, ira->ira_ill,
                    DROPPER(ipss, ipds_ah_nomem),
                    &ahstack->ah_dropper);
                return (NULL);
        }

        oip6h = (ip6_t *)mp->b_rptr;
        icmp6 = (icmp6_t *)((uint8_t *)oip6h + hdr_length);
        ip6h = (ip6_t *)(icmp6 + 1);
        if (!ip_hdr_length_nexthdr_v6(mp, ip6h, &hdr_length, &nexthdrp)) {
                IP_AH_BUMP_STAT(ipss, in_discards);
                ip_drop_packet(mp, B_TRUE, ira->ira_ill,
                    DROPPER(ipss, ipds_ah_bad_v6_hdrs),
                    &ahstack->ah_dropper);
                return (NULL);
        }
        ah = (ah_t *)((uint8_t *)ip6h + hdr_length);

        isaf = OUTBOUND_BUCKET_V6(&ahstack->ah_sadb.s_v6, ip6h->ip6_dst);
        mutex_enter(&isaf->isaf_lock);
        assoc = ipsec_getassocbyspi(isaf, ah->ah_spi,
            (uint32_t *)&ip6h->ip6_src, (uint32_t *)&ip6h->ip6_dst, AF_INET6);
        mutex_exit(&isaf->isaf_lock);

        if (assoc == NULL) {
                IP_AH_BUMP_STAT(ipss, lookup_failure);
                IP_AH_BUMP_STAT(ipss, in_discards);
                if (ahstack->ipsecah_log_unknown_spi) {
                        ipsec_assocfailure(info.mi_idnum, 0, 0,
                            SL_CONSOLE | SL_WARN | SL_ERROR,
                            "Bad ICMP message - No association for the "
                            "attached AH header whose spi is 0x%x, "
                            "sender is 0x%x\n",
                            ah->ah_spi, &oip6h->ip6_src, AF_INET6,
                            ahstack->ipsecah_netstack);
                }
                ip_drop_packet(mp, B_TRUE, ira->ira_ill,
                    DROPPER(ipss, ipds_ah_no_sa),
                    &ahstack->ah_dropper);
                return (NULL);
        }

        IPSA_REFRELE(assoc);

        /*
         * There seems to be a valid association. If there is enough of AH
         * header remove it, otherwise bail.  One could check whether it has
         * complete AH header plus 8 bytes but it does not make sense if an
         * icmp error is returned for ICMP messages e.g ICMP time exceeded,
         * that are being sent up. Let the caller figure out.
         *
         * NOTE: ah_length is the number of 32 bit words minus 2.
         */
        ah_length = (ah->ah_length << 2) + 8;
        post_ah_ptr = (uint8_t *)ah + ah_length;

        if (post_ah_ptr > mp->b_wptr) {
                IP_AH_BUMP_STAT(ipss, in_discards);
                ip_drop_packet(mp, B_TRUE, ira->ira_ill,
                    DROPPER(ipss, ipds_ah_bad_length),
                    &ahstack->ah_dropper);
                return (NULL);
        }

        ip6h->ip6_plen = htons(ntohs(ip6h->ip6_plen) - ah_length);
        *nexthdrp = ah->ah_nexthdr;
        ovbcopy(post_ah_ptr, ah,
            (size_t)((uintptr_t)mp->b_wptr - (uintptr_t)post_ah_ptr));
        mp->b_wptr -= ah_length;

        return (mp);
}

/*
 * IP sends up the ICMP errors for validation and the removal of
 * the AH header.
 * If succesful, the mp has been modified to not include the AH header so
 * that the caller can fanout to the ULP's icmp error handler.
 */
static mblk_t *
ah_icmp_error_v4(mblk_t *mp, ip_recv_attr_t *ira, ipsecah_stack_t *ahstack)
{
        mblk_t *mp1;
        icmph_t *icmph;
        int iph_hdr_length;
        int hdr_length;
        isaf_t *hptr;
        ipsa_t *assoc;
        int ah_length;
        ipha_t *ipha;
        ipha_t *oipha;
        ah_t *ah;
        uint32_t length;
        int alloc_size;
        uint8_t nexthdr;
        ipsec_stack_t   *ipss = ahstack->ipsecah_netstack->netstack_ipsec;

        oipha = ipha = (ipha_t *)mp->b_rptr;
        iph_hdr_length = IPH_HDR_LENGTH(ipha);
        icmph = (icmph_t *)&mp->b_rptr[iph_hdr_length];

        ipha = (ipha_t *)&icmph[1];
        hdr_length = IPH_HDR_LENGTH(ipha);

        /*
         * See if we have enough to locate the SPI
         */
        if ((uchar_t *)ipha + hdr_length + 8 > mp->b_wptr) {
                if (!pullupmsg(mp, (uchar_t *)ipha + hdr_length + 8 -
                    mp->b_rptr)) {
                        ipsec_rl_strlog(ahstack->ipsecah_netstack,
                            info.mi_idnum, 0, 0,
                            SL_WARN | SL_ERROR,
                            "ICMP error: Small AH header\n");
                        IP_AH_BUMP_STAT(ipss, in_discards);
                        ip_drop_packet(mp, B_TRUE, ira->ira_ill,
                            DROPPER(ipss, ipds_ah_bad_length),
                            &ahstack->ah_dropper);
                        return (NULL);
                }
                icmph = (icmph_t *)&mp->b_rptr[iph_hdr_length];
                ipha = (ipha_t *)&icmph[1];
        }

        ah = (ah_t *)((uint8_t *)ipha + hdr_length);
        nexthdr = ah->ah_nexthdr;

        hptr = OUTBOUND_BUCKET_V4(&ahstack->ah_sadb.s_v4, ipha->ipha_dst);
        mutex_enter(&hptr->isaf_lock);
        assoc = ipsec_getassocbyspi(hptr, ah->ah_spi,
            (uint32_t *)&ipha->ipha_src, (uint32_t *)&ipha->ipha_dst, AF_INET);
        mutex_exit(&hptr->isaf_lock);

        if (assoc == NULL) {
                IP_AH_BUMP_STAT(ipss, lookup_failure);
                IP_AH_BUMP_STAT(ipss, in_discards);
                if (ahstack->ipsecah_log_unknown_spi) {
                        ipsec_assocfailure(info.mi_idnum, 0, 0,
                            SL_CONSOLE | SL_WARN | SL_ERROR,
                            "Bad ICMP message - No association for the "
                            "attached AH header whose spi is 0x%x, "
                            "sender is 0x%x\n",
                            ah->ah_spi, &oipha->ipha_src, AF_INET,
                            ahstack->ipsecah_netstack);
                }
                ip_drop_packet(mp, B_TRUE, ira->ira_ill,
                    DROPPER(ipss, ipds_ah_no_sa),
                    &ahstack->ah_dropper);
                return (NULL);
        }

        IPSA_REFRELE(assoc);
        /*
         * There seems to be a valid association. If there
         * is enough of AH header remove it, otherwise remove
         * as much as possible and send it back. One could check
         * whether it has complete AH header plus 8 bytes but it
         * does not make sense if an icmp error is returned for
         * ICMP messages e.g ICMP time exceeded, that are being
         * sent up. Let the caller figure out.
         *
         * NOTE: ah_length is the number of 32 bit words minus 2.
         */
        ah_length = (ah->ah_length << 2) + 8;

        if ((uchar_t *)ipha + hdr_length + ah_length > mp->b_wptr) {
                if (mp->b_cont == NULL) {
                        /*
                         * There is nothing to pullup. Just remove as
                         * much as possible. This is a common case for
                         * IPV4.
                         */
                        ah_length = (mp->b_wptr - ((uchar_t *)ipha +
                            hdr_length));
                        goto done;
                }
                /* Pullup the full ah header */
                if (!pullupmsg(mp, (uchar_t *)ah + ah_length - mp->b_rptr)) {
                        /*
                         * pullupmsg could have failed if there was not
                         * enough to pullup or memory allocation failed.
                         * We tried hard, give up now.
                         */
                        IP_AH_BUMP_STAT(ipss, in_discards);
                        ip_drop_packet(mp, B_TRUE, ira->ira_ill,
                            DROPPER(ipss, ipds_ah_nomem),
                            &ahstack->ah_dropper);
                        return (NULL);
                }
                icmph = (icmph_t *)&mp->b_rptr[iph_hdr_length];
                ipha = (ipha_t *)&icmph[1];
        }
done:
        /*
         * Remove the AH header and change the protocol.
         * Don't update the spi fields in the ip_recv_attr_t
         * as we are called just to validate the
         * message attached to the ICMP message.
         *
         * If we never pulled up since all of the message
         * is in one single mblk, we can't remove the AH header
         * by just setting the b_wptr to the beginning of the
         * AH header. We need to allocate a mblk that can hold
         * up until the inner IP header and copy them.
         */
        alloc_size = iph_hdr_length + sizeof (icmph_t) + hdr_length;

        if ((mp1 = allocb(alloc_size, BPRI_LO)) == NULL) {
                IP_AH_BUMP_STAT(ipss, in_discards);
                ip_drop_packet(mp, B_TRUE, ira->ira_ill,
                    DROPPER(ipss, ipds_ah_nomem),
                    &ahstack->ah_dropper);
                return (NULL);
        }
        bcopy(mp->b_rptr, mp1->b_rptr, alloc_size);
        mp1->b_wptr += alloc_size;

        /*
         * Skip whatever we have copied and as much of AH header
         * possible. If we still have something left in the original
         * message, tag on.
         */
        mp->b_rptr = (uchar_t *)ipha + hdr_length + ah_length;

        if (mp->b_rptr != mp->b_wptr) {
                mp1->b_cont = mp;
        } else {
                if (mp->b_cont != NULL)
                        mp1->b_cont = mp->b_cont;
                freeb(mp);
        }

        ipha = (ipha_t *)(mp1->b_rptr + iph_hdr_length + sizeof (icmph_t));
        ipha->ipha_protocol = nexthdr;
        length = ntohs(ipha->ipha_length);
        length -= ah_length;
        ipha->ipha_length = htons((uint16_t)length);
        ipha->ipha_hdr_checksum = 0;
        ipha->ipha_hdr_checksum = (uint16_t)ip_csum_hdr(ipha);

        return (mp1);
}

/*
 * IP calls this to validate the ICMP errors that
 * we got from the network.
 */
mblk_t *
ipsecah_icmp_error(mblk_t *data_mp, ip_recv_attr_t *ira)
{
        netstack_t      *ns = ira->ira_ill->ill_ipst->ips_netstack;
        ipsecah_stack_t *ahstack = ns->netstack_ipsecah;

        if (ira->ira_flags & IRAF_IS_IPV4)
                return (ah_icmp_error_v4(data_mp, ira, ahstack));
        else
                return (ah_icmp_error_v6(data_mp, ira, ahstack));
}

static int
ah_fix_tlv_options_v6(uint8_t *oi_opt, uint8_t *pi_opt, uint_t ehdrlen,
    uint8_t hdr_type, boolean_t copy_always)
{
        uint8_t opt_type;
        uint_t optlen;

        ASSERT(hdr_type == IPPROTO_DSTOPTS || hdr_type == IPPROTO_HOPOPTS);

        /*
         * Copy the next header and hdr ext. len of the HOP-by-HOP
         * and Destination option.
         */
        *pi_opt++ = *oi_opt++;
        *pi_opt++ = *oi_opt++;
        ehdrlen -= 2;

        /*
         * Now handle all the TLV encoded options.
         */
        while (ehdrlen != 0) {
                opt_type = *oi_opt;

                if (opt_type == IP6OPT_PAD1) {
                        optlen = 1;
                } else {
                        if (ehdrlen < 2)
                                goto bad_opt;
                        optlen = 2 + oi_opt[1];
                        if (optlen > ehdrlen)
                                goto bad_opt;
                }
                if (copy_always || !(opt_type & IP6OPT_MUTABLE)) {
                        bcopy(oi_opt, pi_opt, optlen);
                } else {
                        if (optlen == 1) {
                                *pi_opt = 0;
                        } else {
                                /*
                                 * Copy the type and data length fields.
                                 * Zero the option data by skipping
                                 * option type and option data len
                                 * fields.
                                 */
                                *pi_opt = *oi_opt;
                                *(pi_opt + 1) = *(oi_opt + 1);
                                bzero(pi_opt + 2, optlen - 2);
                        }
                }
                ehdrlen -= optlen;
                oi_opt += optlen;
                pi_opt += optlen;
        }
        return (0);
bad_opt:
        return (-1);
}

/*
 * Construct a pseudo header for AH, processing all the options.
 *
 * oip6h is the IPv6 header of the incoming or outgoing packet.
 * ip6h is the pointer to the pseudo headers IPV6 header. All
 * the space needed for the options have been allocated including
 * the AH header.
 *
 * If copy_always is set, all the options that appear before AH are copied
 * blindly without checking for IP6OPT_MUTABLE. This is used by
 * ah_auth_out_done().  Please refer to that function for details.
 *
 * NOTE :
 *
 * *  AH header is never copied in this function even if copy_always
 *    is set. It just returns the ah_offset - offset of the AH header
 *    and the caller needs to do the copying. This is done so that we
 *    don't have pass extra arguments e.g. SA etc. and also,
 *    it is not needed when ah_auth_out_done is calling this function.
 */
static uint_t
ah_fix_phdr_v6(ip6_t *ip6h, ip6_t *oip6h, boolean_t outbound,
    boolean_t copy_always)
{
        uint8_t *oi_opt;
        uint8_t *pi_opt;
        uint8_t nexthdr;
        uint8_t *prev_nexthdr;
        ip6_hbh_t *hbhhdr;
        ip6_dest_t *dsthdr = NULL;
        ip6_rthdr0_t *rthdr;
        int ehdrlen;
        ah_t *ah;
        int ret;

        /*
         * In the outbound case for source route, ULP has already moved
         * the first hop, which is now in ip6_dst. We need to re-arrange
         * the header to make it look like how it would appear in the
         * receiver i.e
         *
         * Because of ip_massage_options_v6 the header looks like
         * this :
         *
         * ip6_src = S, ip6_dst = I1. followed by I2,I3,D.
         *
         * When it reaches the receiver, it would look like
         *
         * ip6_src = S, ip6_dst = D. followed by I1,I2,I3.
         *
         * NOTE : We assume that there are no problems with the options
         * as IP should have already checked this.
         */

        oi_opt = (uchar_t *)&oip6h[1];
        pi_opt = (uchar_t *)&ip6h[1];

        /*
         * We set the prev_nexthdr properly in the pseudo header.
         * After we finish authentication and come back from the
         * algorithm module, pseudo header will become the real
         * IP header.
         */
        prev_nexthdr = (uint8_t *)&ip6h->ip6_nxt;
        nexthdr = oip6h->ip6_nxt;
        /* Assume IP has already stripped it */
        ASSERT(nexthdr != IPPROTO_FRAGMENT);
        ah = NULL;
        dsthdr = NULL;
        for (;;) {
                switch (nexthdr) {
                case IPPROTO_HOPOPTS:
                        hbhhdr = (ip6_hbh_t *)oi_opt;
                        nexthdr = hbhhdr->ip6h_nxt;
                        ehdrlen = 8 * (hbhhdr->ip6h_len + 1);
                        ret = ah_fix_tlv_options_v6(oi_opt, pi_opt, ehdrlen,
                            IPPROTO_HOPOPTS, copy_always);
                        /*
                         * Return a zero offset indicating error if there
                         * was error.
                         */
                        if (ret == -1)
                                return (0);
                        hbhhdr = (ip6_hbh_t *)pi_opt;
                        prev_nexthdr = (uint8_t *)&hbhhdr->ip6h_nxt;
                        break;
                case IPPROTO_ROUTING:
                        rthdr = (ip6_rthdr0_t *)oi_opt;
                        nexthdr = rthdr->ip6r0_nxt;
                        ehdrlen = 8 * (rthdr->ip6r0_len + 1);
                        if (!copy_always && outbound) {
                                int i, left;
                                ip6_rthdr0_t *prthdr;
                                in6_addr_t *ap, *pap;

                                left = rthdr->ip6r0_segleft;
                                prthdr = (ip6_rthdr0_t *)pi_opt;
                                pap = (in6_addr_t *)(prthdr + 1);
                                ap = (in6_addr_t *)(rthdr + 1);
                                /*
                                 * First eight bytes except seg_left
                                 * does not change en route.
                                 */
                                bcopy(oi_opt, pi_opt, 8);
                                prthdr->ip6r0_segleft = 0;
                                /*
                                 * First address has been moved to
                                 * the destination address of the
                                 * ip header by ip_massage_options_v6.
                                 * And the real destination address is
                                 * in the last address part of the
                                 * option.
                                 */
                                *pap = oip6h->ip6_dst;
                                for (i = 1; i < left - 1; i++)
                                        pap[i] = ap[i - 1];
                                ip6h->ip6_dst = *(ap + left - 1);
                        } else {
                                bcopy(oi_opt, pi_opt, ehdrlen);
                        }
                        rthdr = (ip6_rthdr0_t *)pi_opt;
                        prev_nexthdr = (uint8_t *)&rthdr->ip6r0_nxt;
                        break;
                case IPPROTO_DSTOPTS:
                        /*
                         * Destination options are tricky.  If there is
                         * a terminal (e.g. non-IPv6-extension) header
                         * following the destination options, don't
                         * reset prev_nexthdr or advance the AH insertion
                         * point and just treat this as a terminal header.
                         *
                         * If this is an inbound packet, just deal with
                         * it as is.
                         */
                        dsthdr = (ip6_dest_t *)oi_opt;
                        /*
                         * XXX I hope common-subexpression elimination
                         * saves us the double-evaluate.
                         */
                        if (outbound && dsthdr->ip6d_nxt != IPPROTO_ROUTING &&
                            dsthdr->ip6d_nxt != IPPROTO_HOPOPTS)
                                goto terminal_hdr;
                        nexthdr = dsthdr->ip6d_nxt;
                        ehdrlen = 8 * (dsthdr->ip6d_len + 1);
                        ret = ah_fix_tlv_options_v6(oi_opt, pi_opt, ehdrlen,
                            IPPROTO_DSTOPTS, copy_always);
                        /*
                         * Return a zero offset indicating error if there
                         * was error.
                         */
                        if (ret == -1)
                                return (0);
                        break;
                case IPPROTO_AH:
                        /*
                         * Be conservative in what you send.  We shouldn't
                         * see two same-scoped AH's in one packet.
                         * (Inner-IP-scoped AH will be hit by terminal
                         * header of IP or IPv6.)
                         */
                        ASSERT(!outbound);
                        return ((uint_t)(pi_opt - (uint8_t *)ip6h));
                default:
                        ASSERT(outbound);
terminal_hdr:
                        *prev_nexthdr = IPPROTO_AH;
                        ah = (ah_t *)pi_opt;
                        ah->ah_nexthdr = nexthdr;
                        return ((uint_t)(pi_opt - (uint8_t *)ip6h));
                }
                pi_opt += ehdrlen;
                oi_opt += ehdrlen;
        }
        /* NOTREACHED */
}

static boolean_t
ah_finish_up(ah_t *phdr_ah, ah_t *inbound_ah, ipsa_t *assoc,
    int ah_data_sz, int ah_align_sz, ipsecah_stack_t *ahstack)
{
        int i;

        /*
         * Padding :
         *
         * 1) Authentication data may have to be padded
         * before ICV calculation if ICV is not a multiple
         * of 64 bits. This padding is arbitrary and transmitted
         * with the packet at the end of the authentication data.
         * Payload length should include the padding bytes.
         *
         * 2) Explicit padding of the whole datagram may be
         * required by the algorithm which need not be
         * transmitted. It is assumed that this will be taken
         * care by the algorithm module.
         */
        bzero(phdr_ah + 1, ah_data_sz); /* Zero out ICV for pseudo-hdr. */

        if (inbound_ah == NULL) {
                /* Outbound AH datagram. */

                phdr_ah->ah_length = (ah_align_sz >> 2) + 1;
                phdr_ah->ah_reserved = 0;
                phdr_ah->ah_spi = assoc->ipsa_spi;

                phdr_ah->ah_replay =
                    htonl(atomic_inc_32_nv(&assoc->ipsa_replay));
                if (phdr_ah->ah_replay == 0 && assoc->ipsa_replay_wsize != 0) {
                        /*
                         * XXX We have replay counter wrapping.  We probably
                         * want to nuke this SA (and its peer).
                         */
                        ipsec_assocfailure(info.mi_idnum, 0, 0,
                            SL_ERROR | SL_CONSOLE | SL_WARN,
                            "Outbound AH SA (0x%x), dst %s has wrapped "
                            "sequence.\n", phdr_ah->ah_spi,
                            assoc->ipsa_dstaddr, assoc->ipsa_addrfam,
                            ahstack->ipsecah_netstack);

                        sadb_replay_delete(assoc);
                        /* Caller will free phdr_mp and return NULL. */
                        return (B_FALSE);
                }

                if (ah_data_sz != ah_align_sz) {
                        uchar_t *pad = ((uchar_t *)phdr_ah + sizeof (ah_t) +
                            ah_data_sz);

                        for (i = 0; i < (ah_align_sz - ah_data_sz); i++) {
                                pad[i] = (uchar_t)i;    /* Fill the padding */
                        }
                }
        } else {
                /* Inbound AH datagram. */
                phdr_ah->ah_nexthdr = inbound_ah->ah_nexthdr;
                phdr_ah->ah_length = inbound_ah->ah_length;
                phdr_ah->ah_reserved = 0;
                ASSERT(inbound_ah->ah_spi == assoc->ipsa_spi);
                phdr_ah->ah_spi = inbound_ah->ah_spi;
                phdr_ah->ah_replay = inbound_ah->ah_replay;

                if (ah_data_sz != ah_align_sz) {
                        uchar_t *opad = ((uchar_t *)inbound_ah +
                            sizeof (ah_t) + ah_data_sz);
                        uchar_t *pad = ((uchar_t *)phdr_ah + sizeof (ah_t) +
                            ah_data_sz);

                        for (i = 0; i < (ah_align_sz - ah_data_sz); i++) {
                                pad[i] = opad[i];       /* Copy the padding */
                        }
                }
        }

        return (B_TRUE);
}

/*
 * Called upon failing the inbound ICV check. The message passed as
 * argument is freed.
 */
static void
ah_log_bad_auth(mblk_t *mp, ip_recv_attr_t *ira, ipsec_crypto_t *ic)
{
        boolean_t       isv4 = (ira->ira_flags & IRAF_IS_IPV4);
        ipsa_t          *assoc = ira->ira_ipsec_ah_sa;
        int             af;
        void            *addr;
        netstack_t      *ns = ira->ira_ill->ill_ipst->ips_netstack;
        ipsecah_stack_t *ahstack = ns->netstack_ipsecah;
        ipsec_stack_t   *ipss = ns->netstack_ipsec;

        ASSERT(mp->b_datap->db_type == M_DATA);

        mp->b_rptr -= ic->ic_skip_len;

        if (isv4) {
                ipha_t *ipha = (ipha_t *)mp->b_rptr;
                addr = &ipha->ipha_dst;
                af = AF_INET;
        } else {
                ip6_t *ip6h = (ip6_t *)mp->b_rptr;
                addr = &ip6h->ip6_dst;
                af = AF_INET6;
        }

        /*
         * Log the event. Don't print to the console, block
         * potential denial-of-service attack.
         */
        AH_BUMP_STAT(ahstack, bad_auth);

        ipsec_assocfailure(info.mi_idnum, 0, 0, SL_ERROR | SL_WARN,
            "AH Authentication failed spi %x, dst_addr %s",
            assoc->ipsa_spi, addr, af, ahstack->ipsecah_netstack);

        IP_AH_BUMP_STAT(ipss, in_discards);
        ip_drop_packet(mp, B_TRUE, ira->ira_ill,
            DROPPER(ipss, ipds_ah_bad_auth),
            &ahstack->ah_dropper);
}

/*
 * Kernel crypto framework callback invoked after completion of async
 * crypto requests for outbound packets.
 */
static void
ah_kcf_callback_outbound(void *arg, int status)
{
        mblk_t          *mp = (mblk_t *)arg;
        mblk_t          *async_mp;
        netstack_t      *ns;
        ipsec_stack_t   *ipss;
        ipsecah_stack_t *ahstack;
        mblk_t          *data_mp;
        ip_xmit_attr_t  ixas;
        ipsec_crypto_t  *ic;
        ill_t           *ill;

        /*
         * First remove the ipsec_crypto_t mblk
         * Note that we need to ipsec_free_crypto_data(mp) once done with ic.
         */
        async_mp = ipsec_remove_crypto_data(mp, &ic);
        ASSERT(async_mp != NULL);

        /*
         * Extract the ip_xmit_attr_t from the first mblk.
         * Verifies that the netstack and ill is still around; could
         * have vanished while kEf was doing its work.
         * On succesful return we have a nce_t and the ill/ipst can't
         * disappear until we do the nce_refrele in ixa_cleanup.
         */
        data_mp = async_mp->b_cont;
        async_mp->b_cont = NULL;
        if (!ip_xmit_attr_from_mblk(async_mp, &ixas)) {
                /* Disappeared on us - no ill/ipst for MIB */
                if (ixas.ixa_nce != NULL) {
                        ill = ixas.ixa_nce->nce_ill;
                        BUMP_MIB(ill->ill_ip_mib, ipIfStatsOutDiscards);
                        ip_drop_output("ipIfStatsOutDiscards", data_mp, ill);
                }
                freemsg(data_mp);
                goto done;
        }
        ns = ixas.ixa_ipst->ips_netstack;
        ahstack = ns->netstack_ipsecah;
        ipss = ns->netstack_ipsec;
        ill = ixas.ixa_nce->nce_ill;

        if (status == CRYPTO_SUCCESS) {
                data_mp = ah_auth_out_done(data_mp, &ixas, ic);
                if (data_mp == NULL)
                        goto done;

                (void) ip_output_post_ipsec(data_mp, &ixas);
        } else {
                /* Outbound shouldn't see invalid MAC */
                ASSERT(status != CRYPTO_INVALID_MAC);

                ah1dbg(ahstack,
                    ("ah_kcf_callback_outbound: crypto failed with 0x%x\n",
                    status));
                AH_BUMP_STAT(ahstack, crypto_failures);
                AH_BUMP_STAT(ahstack, out_discards);

                ip_drop_packet(data_mp, B_FALSE, ill,
                    DROPPER(ipss, ipds_ah_crypto_failed),
                    &ahstack->ah_dropper);
                BUMP_MIB(ill->ill_ip_mib, ipIfStatsOutDiscards);
        }
done:
        ixa_cleanup(&ixas);
        (void) ipsec_free_crypto_data(mp);
}

/*
 * Kernel crypto framework callback invoked after completion of async
 * crypto requests for inbound packets.
 */
static void
ah_kcf_callback_inbound(void *arg, int status)
{
        mblk_t          *mp = (mblk_t *)arg;
        mblk_t          *async_mp;
        netstack_t      *ns;
        ipsec_stack_t   *ipss;
        ipsecah_stack_t *ahstack;
        mblk_t          *data_mp;
        ip_recv_attr_t  iras;
        ipsec_crypto_t  *ic;

        /*
         * First remove the ipsec_crypto_t mblk
         * Note that we need to ipsec_free_crypto_data(mp) once done with ic.
         */
        async_mp = ipsec_remove_crypto_data(mp, &ic);
        ASSERT(async_mp != NULL);

        /*
         * Extract the ip_xmit_attr_t from the first mblk.
         * Verifies that the netstack and ill is still around; could
         * have vanished while kEf was doing its work.
         */
        data_mp = async_mp->b_cont;
        async_mp->b_cont = NULL;
        if (!ip_recv_attr_from_mblk(async_mp, &iras)) {
                /* The ill or ip_stack_t disappeared on us */
                ip_drop_input("ip_recv_attr_from_mblk", data_mp, NULL);
                freemsg(data_mp);
                goto done;
        }
        ns = iras.ira_ill->ill_ipst->ips_netstack;
        ahstack = ns->netstack_ipsecah;
        ipss = ns->netstack_ipsec;

        if (status == CRYPTO_SUCCESS) {
                data_mp = ah_auth_in_done(data_mp, &iras, ic);
                if (data_mp == NULL)
                        goto done;

                /* finish IPsec processing */
                ip_input_post_ipsec(data_mp, &iras);

        } else if (status == CRYPTO_INVALID_MAC) {
                ah_log_bad_auth(data_mp, &iras, ic);
        } else {
                ah1dbg(ahstack,
                    ("ah_kcf_callback_inbound: crypto failed with 0x%x\n",
                    status));
                AH_BUMP_STAT(ahstack, crypto_failures);
                IP_AH_BUMP_STAT(ipss, in_discards);
                ip_drop_packet(data_mp, B_TRUE, iras.ira_ill,
                    DROPPER(ipss, ipds_ah_crypto_failed),
                    &ahstack->ah_dropper);
                BUMP_MIB(iras.ira_ill->ill_ip_mib, ipIfStatsInDiscards);
        }
done:
        ira_cleanup(&iras, B_TRUE);
        (void) ipsec_free_crypto_data(mp);
}

/*
 * Invoked on kernel crypto failure during inbound and outbound processing.
 */
static void
ah_crypto_failed(mblk_t *data_mp, boolean_t is_inbound, int kef_rc,
    ill_t *ill, ipsecah_stack_t *ahstack)
{
        ipsec_stack_t   *ipss = ahstack->ipsecah_netstack->netstack_ipsec;

        ah1dbg(ahstack, ("crypto failed for %s AH with 0x%x\n",
            is_inbound ? "inbound" : "outbound", kef_rc));
        ip_drop_packet(data_mp, is_inbound, ill,
            DROPPER(ipss, ipds_ah_crypto_failed),
            &ahstack->ah_dropper);
        AH_BUMP_STAT(ahstack, crypto_failures);
        if (is_inbound)
                IP_AH_BUMP_STAT(ipss, in_discards);
        else
                AH_BUMP_STAT(ahstack, out_discards);
}

/*
 * Helper macros for the ah_submit_req_{inbound,outbound}() functions.
 */

/*
 * A statement-equivalent macro, _cr MUST point to a modifiable
 * crypto_call_req_t.
 */
#define AH_INIT_CALLREQ(_cr, _mp, _callback)            \
        (_cr)->cr_flag = CRYPTO_SKIP_REQID|CRYPTO_ALWAYS_QUEUE; \
        (_cr)->cr_callback_arg = (_mp);                         \
        (_cr)->cr_callback_func = (_callback)

#define AH_INIT_CRYPTO_DATA(data, msglen, mblk) {                       \
        (data)->cd_format = CRYPTO_DATA_MBLK;                           \
        (data)->cd_mp = mblk;                                           \
        (data)->cd_offset = 0;                                          \
        (data)->cd_length = msglen;                                     \
}

#define AH_INIT_CRYPTO_MAC(mac, icvlen, icvbuf) {                       \
        (mac)->cd_format = CRYPTO_DATA_RAW;                             \
        (mac)->cd_offset = 0;                                           \
        (mac)->cd_length = icvlen;                                      \
        (mac)->cd_raw.iov_base = icvbuf;                                \
        (mac)->cd_raw.iov_len = icvlen;                                 \
}

/*
 * Submit an inbound packet for processing by the crypto framework.
 */
static mblk_t *
ah_submit_req_inbound(mblk_t *phdr_mp, ip_recv_attr_t *ira,
    size_t skip_len, uint32_t ah_offset, ipsa_t *assoc)
{
        int kef_rc;
        mblk_t *mp;
        crypto_call_req_t call_req, *callrp;
        uint_t icv_len = assoc->ipsa_mac_len;
        crypto_ctx_template_t ctx_tmpl;
        ipsecah_stack_t *ahstack;
        ipsec_crypto_t  *ic, icstack;
        boolean_t force = (assoc->ipsa_flags & IPSA_F_ASYNC);

        ahstack = ira->ira_ill->ill_ipst->ips_netstack->netstack_ipsecah;

        ASSERT(phdr_mp != NULL);
        ASSERT(phdr_mp->b_datap->db_type == M_DATA);

        if (force) {
                /* We are doing asynch; allocate mblks to hold state */
                if ((mp = ip_recv_attr_to_mblk(ira)) == NULL ||
                    (mp = ipsec_add_crypto_data(mp, &ic)) == NULL) {
                        BUMP_MIB(ira->ira_ill->ill_ip_mib, ipIfStatsInDiscards);
                        ip_drop_input("ipIfStatsInDiscards", phdr_mp,
                            ira->ira_ill);
                        freemsg(phdr_mp);
                        return (NULL);
                }

                linkb(mp, phdr_mp);
                callrp = &call_req;
                AH_INIT_CALLREQ(callrp, mp, ah_kcf_callback_inbound);
        } else {
                /*
                 * If we know we are going to do sync then ipsec_crypto_t
                 * should be on the stack.
                 */
                ic = &icstack;
                bzero(ic, sizeof (*ic));
                callrp = NULL;
        }

        /* init arguments for the crypto framework */
        AH_INIT_CRYPTO_DATA(&ic->ic_crypto_data, AH_MSGSIZE(phdr_mp),
            phdr_mp);

        AH_INIT_CRYPTO_MAC(&ic->ic_crypto_mac, icv_len,
            (char *)phdr_mp->b_cont->b_rptr - skip_len + ah_offset +
            sizeof (ah_t));

        ic->ic_skip_len = skip_len;

        IPSEC_CTX_TMPL(assoc, ipsa_authtmpl, IPSEC_ALG_AUTH, ctx_tmpl);

        /* call KEF to do the MAC operation */
        kef_rc = crypto_mac_verify(&assoc->ipsa_amech,
            &ic->ic_crypto_data, &assoc->ipsa_kcfauthkey, ctx_tmpl,
            &ic->ic_crypto_mac, callrp);

        switch (kef_rc) {
        case CRYPTO_SUCCESS:
                AH_BUMP_STAT(ahstack, crypto_sync);
                phdr_mp = ah_auth_in_done(phdr_mp, ira, ic);
                if (force) {
                        /* Free mp after we are done with ic */
                        mp = ipsec_free_crypto_data(mp);
                        (void) ip_recv_attr_free_mblk(mp);
                }
                return (phdr_mp);
        case CRYPTO_QUEUED:
                /* ah_kcf_callback_inbound() will be invoked on completion */
                AH_BUMP_STAT(ahstack, crypto_async);
                return (NULL);
        case CRYPTO_INVALID_MAC:
                /* Free mp after we are done with ic */
                AH_BUMP_STAT(ahstack, crypto_sync);
                BUMP_MIB(ira->ira_ill->ill_ip_mib, ipIfStatsInDiscards);
                ah_log_bad_auth(phdr_mp, ira, ic);
                /* phdr_mp was passed to ip_drop_packet */
                if (force) {
                        mp = ipsec_free_crypto_data(mp);
                        (void) ip_recv_attr_free_mblk(mp);
                }
                return (NULL);
        }

        if (force) {
                mp = ipsec_free_crypto_data(mp);
                phdr_mp = ip_recv_attr_free_mblk(mp);
        }
        BUMP_MIB(ira->ira_ill->ill_ip_mib, ipIfStatsInDiscards);
        ah_crypto_failed(phdr_mp, B_TRUE, kef_rc, ira->ira_ill, ahstack);
        /* phdr_mp was passed to ip_drop_packet */
        return (NULL);
}

/*
 * Submit an outbound packet for processing by the crypto framework.
 */
static mblk_t *
ah_submit_req_outbound(mblk_t *phdr_mp, ip_xmit_attr_t *ixa,
    size_t skip_len, ipsa_t *assoc)
{
        int kef_rc;
        mblk_t *mp;
        crypto_call_req_t call_req, *callrp;
        uint_t icv_len = assoc->ipsa_mac_len;
        ipsecah_stack_t *ahstack;
        ipsec_crypto_t  *ic, icstack;
        ill_t           *ill = ixa->ixa_nce->nce_ill;
        boolean_t force = (assoc->ipsa_flags & IPSA_F_ASYNC);

        ahstack = ill->ill_ipst->ips_netstack->netstack_ipsecah;

        ASSERT(phdr_mp != NULL);
        ASSERT(phdr_mp->b_datap->db_type == M_DATA);

        if (force) {
                /* We are doing asynch; allocate mblks to hold state */
                if ((mp = ip_xmit_attr_to_mblk(ixa)) == NULL ||
                    (mp = ipsec_add_crypto_data(mp, &ic)) == NULL) {
                        BUMP_MIB(ill->ill_ip_mib, ipIfStatsOutDiscards);
                        ip_drop_output("ipIfStatsOutDiscards", phdr_mp, ill);
                        freemsg(phdr_mp);
                        return (NULL);
                }
                linkb(mp, phdr_mp);
                callrp = &call_req;
                AH_INIT_CALLREQ(callrp, mp, ah_kcf_callback_outbound);
        } else {
                /*
                 * If we know we are going to do sync then ipsec_crypto_t
                 * should be on the stack.
                 */
                ic = &icstack;
                bzero(ic, sizeof (*ic));
                callrp = NULL;
        }

        /* init arguments for the crypto framework */
        AH_INIT_CRYPTO_DATA(&ic->ic_crypto_data, AH_MSGSIZE(phdr_mp),
            phdr_mp);

        AH_INIT_CRYPTO_MAC(&ic->ic_crypto_mac, icv_len,
            (char *)phdr_mp->b_wptr);

        ic->ic_skip_len = skip_len;

        ASSERT(ixa->ixa_ipsec_ah_sa != NULL);

        /* call KEF to do the MAC operation */
        kef_rc = crypto_mac(&assoc->ipsa_amech, &ic->ic_crypto_data,
            &assoc->ipsa_kcfauthkey, assoc->ipsa_authtmpl,
            &ic->ic_crypto_mac, callrp);

        switch (kef_rc) {
        case CRYPTO_SUCCESS:
                AH_BUMP_STAT(ahstack, crypto_sync);
                phdr_mp = ah_auth_out_done(phdr_mp, ixa, ic);
                if (force) {
                        /* Free mp after we are done with ic */
                        mp = ipsec_free_crypto_data(mp);
                        (void) ip_xmit_attr_free_mblk(mp);
                }
                return (phdr_mp);
        case CRYPTO_QUEUED:
                /* ah_kcf_callback_outbound() will be invoked on completion */
                AH_BUMP_STAT(ahstack, crypto_async);
                return (NULL);
        }

        if (force) {
                mp = ipsec_free_crypto_data(mp);
                phdr_mp = ip_xmit_attr_free_mblk(mp);
        }
        BUMP_MIB(ill->ill_ip_mib, ipIfStatsOutDiscards);
        ah_crypto_failed(phdr_mp, B_FALSE, kef_rc, NULL, ahstack);
        /* phdr_mp was passed to ip_drop_packet */
        return (NULL);
}

/*
 * This function constructs a pseudo header by looking at the IP header
 * and options if any. This is called for both outbound and inbound,
 * before computing the ICV.
 */
static mblk_t *
ah_process_ip_options_v6(mblk_t *mp, ipsa_t *assoc, int *length_to_skip,
    uint_t ah_data_sz, boolean_t outbound, ipsecah_stack_t *ahstack)
{
        ip6_t   *ip6h;
        ip6_t   *oip6h;
        mblk_t  *phdr_mp;
        int option_length;
        uint_t  ah_align_sz;
        uint_t ah_offset;
        int hdr_size;

        /*
         * Allocate space for the authentication data also. It is
         * useful both during the ICV calculation where we need to
         * feed in zeroes and while sending the datagram back to IP
         * where we will be using the same space.
         *
         * We need to allocate space for padding bytes if it is not
         * a multiple of IPV6_PADDING_ALIGN.
         *
         * In addition, we allocate space for the ICV computed by
         * the kernel crypto framework, saving us a separate kmem
         * allocation down the road.
         */

        ah_align_sz = P2ALIGN(ah_data_sz + IPV6_PADDING_ALIGN - 1,
            IPV6_PADDING_ALIGN);

        ASSERT(ah_align_sz >= ah_data_sz);

        hdr_size = ipsec_ah_get_hdr_size_v6(mp, B_FALSE);
        option_length = hdr_size - IPV6_HDR_LEN;

        /* This was not included in ipsec_ah_get_hdr_size_v6() */
        hdr_size += (sizeof (ah_t) + ah_align_sz);

        if (!outbound && (MBLKL(mp) < hdr_size)) {
                /*
                 * We have post-AH header options in a separate mblk,
                 * a pullup is required.
                 */
                if (!pullupmsg(mp, hdr_size))
                        return (NULL);
        }

        if ((phdr_mp = allocb_tmpl(hdr_size + ah_data_sz, mp)) == NULL) {
                return (NULL);
        }

        oip6h = (ip6_t *)mp->b_rptr;

        /*
         * Form the basic IP header first. Zero out the header
         * so that the mutable fields are zeroed out.
         */
        ip6h = (ip6_t *)phdr_mp->b_rptr;
        bzero(ip6h, sizeof (ip6_t));
        ip6h->ip6_vcf = IPV6_DEFAULT_VERS_AND_FLOW;

        if (outbound) {
                /*
                 * Include the size of AH and authentication data.
                 * This is how our recipient would compute the
                 * authentication data. Look at what we do in the
                 * inbound case below.
                 */
                ip6h->ip6_plen = htons(ntohs(oip6h->ip6_plen) +
                    sizeof (ah_t) + ah_align_sz);
        } else {
                ip6h->ip6_plen = oip6h->ip6_plen;
        }

        ip6h->ip6_src = oip6h->ip6_src;
        ip6h->ip6_dst = oip6h->ip6_dst;

        *length_to_skip = IPV6_HDR_LEN;
        if (option_length == 0) {
                /* Form the AH header */
                ip6h->ip6_nxt = IPPROTO_AH;
                ((ah_t *)(ip6h + 1))->ah_nexthdr = oip6h->ip6_nxt;
                ah_offset = *length_to_skip;
        } else {
                ip6h->ip6_nxt = oip6h->ip6_nxt;
                /* option_length does not include the AH header's size */
                *length_to_skip += option_length;

                ah_offset = ah_fix_phdr_v6(ip6h, oip6h, outbound, B_FALSE);
                if (ah_offset == 0) {
                        return (NULL);
                }
        }

        if (!ah_finish_up(((ah_t *)((uint8_t *)ip6h + ah_offset)),
            (outbound ? NULL : ((ah_t *)((uint8_t *)oip6h + ah_offset))),
            assoc, ah_data_sz, ah_align_sz, ahstack)) {
                freeb(phdr_mp);
                /*
                 * Returning NULL will tell the caller to
                 * IPSA_REFELE(), free the memory, etc.
                 */
                return (NULL);
        }

        phdr_mp->b_wptr = ((uint8_t *)ip6h + ah_offset + sizeof (ah_t) +
            ah_align_sz);
        if (!outbound)
                *length_to_skip += sizeof (ah_t) + ah_align_sz;
        return (phdr_mp);
}

/*
 * This function constructs a pseudo header by looking at the IP header
 * and options if any. This is called for both outbound and inbound,
 * before computing the ICV.
 */
static mblk_t *
ah_process_ip_options_v4(mblk_t *mp, ipsa_t *assoc, int *length_to_skip,
    uint_t ah_data_sz, boolean_t outbound, ipsecah_stack_t *ahstack)
{
        ipoptp_t opts;
        uint32_t option_length;
        ipha_t  *ipha;
        ipha_t  *oipha;
        mblk_t  *phdr_mp;
        int      size;
        uchar_t *optptr;
        uint8_t optval;
        uint8_t optlen;
        ipaddr_t dst;
        uint32_t v_hlen_tos_len;
        int ip_hdr_length;
        uint_t  ah_align_sz;
        uint32_t off;

#ifdef  _BIG_ENDIAN
#define V_HLEN  (v_hlen_tos_len >> 24)
#else
#define V_HLEN  (v_hlen_tos_len & 0xFF)
#endif

        oipha = (ipha_t *)mp->b_rptr;
        v_hlen_tos_len = ((uint32_t *)oipha)[0];

        /*
         * Allocate space for the authentication data also. It is
         * useful both during the ICV calculation where we need to
         * feed in zeroes and while sending the datagram back to IP
         * where we will be using the same space.
         *
         * We need to allocate space for padding bytes if it is not
         * a multiple of IPV4_PADDING_ALIGN.
         *
         * In addition, we allocate space for the ICV computed by
         * the kernel crypto framework, saving us a separate kmem
         * allocation down the road.
         */

        ah_align_sz = P2ALIGN(ah_data_sz + IPV4_PADDING_ALIGN - 1,
            IPV4_PADDING_ALIGN);

        ASSERT(ah_align_sz >= ah_data_sz);

        size = IP_SIMPLE_HDR_LENGTH + sizeof (ah_t) + ah_align_sz +
            ah_data_sz;

        if (V_HLEN != IP_SIMPLE_HDR_VERSION) {
                option_length = oipha->ipha_version_and_hdr_length -
                    (uint8_t)((IP_VERSION << 4) +
                    IP_SIMPLE_HDR_LENGTH_IN_WORDS);
                option_length <<= 2;
                size += option_length;
        }

        if ((phdr_mp = allocb_tmpl(size, mp)) == NULL) {
                return (NULL);
        }

        /*
         * Form the basic IP header first.
         */
        ipha = (ipha_t *)phdr_mp->b_rptr;
        ipha->ipha_version_and_hdr_length = oipha->ipha_version_and_hdr_length;
        ipha->ipha_type_of_service = 0;

        if (outbound) {
                /*
                 * Include the size of AH and authentication data.
                 * This is how our recipient would compute the
                 * authentication data. Look at what we do in the
                 * inbound case below.
                 */
                ipha->ipha_length = ntohs(htons(oipha->ipha_length) +
                    sizeof (ah_t) + ah_align_sz);
        } else {
                ipha->ipha_length = oipha->ipha_length;
        }

        ipha->ipha_ident = oipha->ipha_ident;
        ipha->ipha_fragment_offset_and_flags = 0;
        ipha->ipha_ttl = 0;
        ipha->ipha_protocol = IPPROTO_AH;
        ipha->ipha_hdr_checksum = 0;
        ipha->ipha_src = oipha->ipha_src;
        ipha->ipha_dst = dst = oipha->ipha_dst;

        /*
         * If there is no option to process return now.
         */
        ip_hdr_length = IP_SIMPLE_HDR_LENGTH;

        if (V_HLEN == IP_SIMPLE_HDR_VERSION) {
                /* Form the AH header */
                goto ah_hdr;
        }

        ip_hdr_length += option_length;

        /*
         * We have options. In the outbound case for source route,
         * ULP has already moved the first hop, which is now in
         * ipha_dst. We need the final destination for the calculation
         * of authentication data. And also make sure that mutable
         * and experimental fields are zeroed out in the IP options.
         */

        bcopy(&oipha[1], &ipha[1], option_length);

        for (optval = ipoptp_first(&opts, ipha);
            optval != IPOPT_EOL;
            optval = ipoptp_next(&opts)) {
                optptr = opts.ipoptp_cur;
                optlen = opts.ipoptp_len;
                switch (optval) {
                case IPOPT_EXTSEC:
                case IPOPT_COMSEC:
                case IPOPT_RA:
                case IPOPT_SDMDD:
                case IPOPT_SECURITY:
                        /*
                         * These options are Immutable, leave them as-is.
                         * Note that IPOPT_NOP is also Immutable, but it
                         * was skipped by ipoptp_next() and thus remains
                         * intact in the header.
                         */
                        break;
                case IPOPT_SSRR:
                case IPOPT_LSRR:
                        if ((opts.ipoptp_flags & IPOPTP_ERROR) != 0)
                                goto bad_ipv4opt;
                        /*
                         * These two are mutable and will be zeroed, but
                         * first get the final destination.
                         */
                        off = optptr[IPOPT_OFFSET];
                        /*
                         * If one of the conditions is true, it means
                         * end of options and dst already has the right
                         * value. So, just fall through.
                         */
                        if (!(optlen < IP_ADDR_LEN || off > optlen - 3)) {
                                off = optlen - IP_ADDR_LEN;
                                bcopy(&optptr[off], &dst, IP_ADDR_LEN);
                        }
                        /* FALLTHRU */
                case IPOPT_RR:
                case IPOPT_TS:
                case IPOPT_SATID:
                default:
                        /*
                         * optlen should include from the beginning of an
                         * option.
                         * NOTE : Stream Identifier Option (SID): RFC 791
                         * shows the bit pattern of optlen as 2 and documents
                         * the length as 4. We assume it to be 2 here.
                         */
                        bzero(optptr, optlen);
                        break;
                }
        }

        if ((opts.ipoptp_flags & IPOPTP_ERROR) != 0) {
bad_ipv4opt:
                ah1dbg(ahstack, ("AH : bad IPv4 option"));
                freeb(phdr_mp);
                return (NULL);
        }

        /*
         * Don't change ipha_dst for an inbound datagram as it points
         * to the right value. Only for the outbound with LSRR/SSRR,
         * because of ip_massage_options called by the ULP, ipha_dst
         * points to the first hop and we need to use the final
         * destination for computing the ICV.
         */

        if (outbound)
                ipha->ipha_dst = dst;
ah_hdr:
        ((ah_t *)((uint8_t *)ipha + ip_hdr_length))->ah_nexthdr =
            oipha->ipha_protocol;
        if (!ah_finish_up(((ah_t *)((uint8_t *)ipha + ip_hdr_length)),
            (outbound ? NULL : ((ah_t *)((uint8_t *)oipha + ip_hdr_length))),
            assoc, ah_data_sz, ah_align_sz, ahstack)) {
                freeb(phdr_mp);
                /*
                 * Returning NULL will tell the caller to IPSA_REFELE(), free
                 * the memory, etc.
                 */
                return (NULL);
        }

        phdr_mp->b_wptr = ((uchar_t *)ipha + ip_hdr_length +
            sizeof (ah_t) + ah_align_sz);

        ASSERT(phdr_mp->b_wptr <= phdr_mp->b_datap->db_lim);
        if (outbound)
                *length_to_skip = ip_hdr_length;
        else
                *length_to_skip = ip_hdr_length + sizeof (ah_t) + ah_align_sz;
        return (phdr_mp);
}

/*
 * Authenticate an outbound datagram. This function is called
 * whenever IP sends an outbound datagram that needs authentication.
 * Returns a modified packet if done. Returns NULL if error or queued.
 * If error return then ipIfStatsOutDiscards has been increased.
 */
static mblk_t *
ah_outbound(mblk_t *data_mp, ip_xmit_attr_t *ixa)
{
        mblk_t *phdr_mp;
        ipsa_t *assoc;
        int length_to_skip;
        uint_t ah_align_sz;
        uint_t age_bytes;
        netstack_t      *ns = ixa->ixa_ipst->ips_netstack;
        ipsecah_stack_t *ahstack = ns->netstack_ipsecah;
        ipsec_stack_t   *ipss = ns->netstack_ipsec;
        ill_t           *ill = ixa->ixa_nce->nce_ill;
        boolean_t       need_refrele = B_FALSE;

        /*
         * Construct the chain of mblks
         *
         * PSEUDO_HDR->DATA
         *
         * one by one.
         */

        AH_BUMP_STAT(ahstack, out_requests);

        ASSERT(data_mp->b_datap->db_type == M_DATA);

        assoc = ixa->ixa_ipsec_ah_sa;
        ASSERT(assoc != NULL);


        /*
         * Get the outer IP header in shape to escape this system..
         */
        if (is_system_labeled() && (assoc->ipsa_otsl != NULL)) {
                /*
                 * Need to update packet with any CIPSO option and update
                 * ixa_tsl to capture the new label.
                 * We allocate a separate ixa for that purpose.
                 */
                ixa = ip_xmit_attr_duplicate(ixa);
                if (ixa == NULL) {
                        ip_drop_packet(data_mp, B_FALSE, ill,
                            DROPPER(ipss, ipds_ah_nomem),
                            &ahstack->ah_dropper);
                        return (NULL);
                }
                need_refrele = B_TRUE;

                label_hold(assoc->ipsa_otsl);
                ip_xmit_attr_replace_tsl(ixa, assoc->ipsa_otsl);

                data_mp = sadb_whack_label(data_mp, assoc, ixa,
                    DROPPER(ipss, ipds_ah_nomem), &ahstack->ah_dropper);
                if (data_mp == NULL) {
                        /* Packet dropped by sadb_whack_label */
                        ixa_refrele(ixa);
                        return (NULL);
                }
        }

        /*
         * Age SA according to number of bytes that will be sent after
         * adding the AH header, ICV, and padding to the packet.
         */

        if (ixa->ixa_flags & IXAF_IS_IPV4) {
                ipha_t *ipha = (ipha_t *)data_mp->b_rptr;
                ah_align_sz = P2ALIGN(assoc->ipsa_mac_len +
                    IPV4_PADDING_ALIGN - 1, IPV4_PADDING_ALIGN);
                age_bytes = ntohs(ipha->ipha_length) + sizeof (ah_t) +
                    ah_align_sz;
        } else {
                ip6_t *ip6h = (ip6_t *)data_mp->b_rptr;
                ah_align_sz = P2ALIGN(assoc->ipsa_mac_len +
                    IPV6_PADDING_ALIGN - 1, IPV6_PADDING_ALIGN);
                age_bytes = sizeof (ip6_t) + ntohs(ip6h->ip6_plen) +
                    sizeof (ah_t) + ah_align_sz;
        }

        if (!ah_age_bytes(assoc, age_bytes, B_FALSE)) {
                /* rig things as if ipsec_getassocbyconn() failed */
                ipsec_assocfailure(info.mi_idnum, 0, 0, SL_ERROR | SL_WARN,
                    "AH association 0x%x, dst %s had bytes expire.\n",
                    ntohl(assoc->ipsa_spi), assoc->ipsa_dstaddr, AF_INET,
                    ahstack->ipsecah_netstack);
                BUMP_MIB(ill->ill_ip_mib, ipIfStatsOutDiscards);
                ip_drop_output("ipIfStatsOutDiscards", data_mp, ill);
                freemsg(data_mp);
                if (need_refrele)
                        ixa_refrele(ixa);
                return (NULL);
        }

        /*
         * XXX We need to have fixed up the outer label before we get here.
         * (AH is computing the checksum over the outer label).
         */

        /*
         * Insert pseudo header:
         * [IP, ULP] => [IP, AH, ICV] -> ULP
         */

        if (ixa->ixa_flags & IXAF_IS_IPV4) {
                phdr_mp = ah_process_ip_options_v4(data_mp, assoc,
                    &length_to_skip, assoc->ipsa_mac_len, B_TRUE, ahstack);
        } else {
                phdr_mp = ah_process_ip_options_v6(data_mp, assoc,
                    &length_to_skip, assoc->ipsa_mac_len, B_TRUE, ahstack);
        }

        if (phdr_mp == NULL) {
                AH_BUMP_STAT(ahstack, out_discards);
                ip_drop_packet(data_mp, B_FALSE, ixa->ixa_nce->nce_ill,
                    DROPPER(ipss, ipds_ah_bad_v4_opts),
                    &ahstack->ah_dropper);
                BUMP_MIB(ill->ill_ip_mib, ipIfStatsOutDiscards);
                if (need_refrele)
                        ixa_refrele(ixa);
                return (NULL);
        }

        phdr_mp->b_cont = data_mp;
        data_mp->b_rptr += length_to_skip;
        data_mp = phdr_mp;

        /*
         * At this point data_mp points to
         * an mblk containing the pseudo header (IP header,
         * AH header, and ICV with mutable fields zero'ed out).
         * mp points to the mblk containing the ULP data. The original
         * IP header is kept before the ULP data in data_mp.
         */

        /* submit MAC request to KCF */
        data_mp = ah_submit_req_outbound(data_mp, ixa, length_to_skip, assoc);
        if (need_refrele)
                ixa_refrele(ixa);
        return (data_mp);
}

static mblk_t *
ah_inbound(mblk_t *data_mp, void *arg, ip_recv_attr_t *ira)
{
        ah_t            *ah = (ah_t *)arg;
        ipsa_t          *assoc = ira->ira_ipsec_ah_sa;
        int             length_to_skip;
        int             ah_length;
        mblk_t          *phdr_mp;
        uint32_t        ah_offset;
        netstack_t      *ns = ira->ira_ill->ill_ipst->ips_netstack;
        ipsecah_stack_t *ahstack = ns->netstack_ipsecah;
        ipsec_stack_t   *ipss = ns->netstack_ipsec;

        ASSERT(assoc != NULL);

        /*
         * We may wish to check replay in-range-only here as an optimization.
         * Include the reality check of ipsa->ipsa_replay >
         * ipsa->ipsa_replay_wsize for times when it's the first N packets,
         * where N == ipsa->ipsa_replay_wsize.
         *
         * Another check that may come here later is the "collision" check.
         * If legitimate packets flow quickly enough, this won't be a problem,
         * but collisions may cause authentication algorithm crunching to
         * take place when it doesn't need to.
         */
        if (!sadb_replay_peek(assoc, ah->ah_replay)) {
                AH_BUMP_STAT(ahstack, replay_early_failures);
                IP_AH_BUMP_STAT(ipss, in_discards);
                ip_drop_packet(data_mp, B_TRUE, ira->ira_ill,
                    DROPPER(ipss, ipds_ah_early_replay),
                    &ahstack->ah_dropper);
                BUMP_MIB(ira->ira_ill->ill_ip_mib, ipIfStatsInDiscards);
                return (NULL);
        }

        /*
         * The offset of the AH header can be computed from its pointer
         * within the data mblk, which was pulled up until the AH header
         * by ipsec_inbound_ah_sa() during SA selection.
         */
        ah_offset = (uchar_t *)ah - data_mp->b_rptr;

        /*
         * We need to pullup until the ICV before we call
         * ah_process_ip_options_v6.
         */
        ah_length = (ah->ah_length << 2) + 8;

        /*
         * NOTE : If we want to use any field of IP/AH header, you need
         * to re-assign following the pullup.
         */
        if (((uchar_t *)ah + ah_length) > data_mp->b_wptr) {
                if (!pullupmsg(data_mp, (uchar_t *)ah + ah_length -
                    data_mp->b_rptr)) {
                        (void) ipsec_rl_strlog(ns, info.mi_idnum, 0, 0,
                            SL_WARN | SL_ERROR,
                            "ah_inbound: Small AH header\n");
                        IP_AH_BUMP_STAT(ipss, in_discards);
                        ip_drop_packet(data_mp, B_TRUE, ira->ira_ill,
                            DROPPER(ipss, ipds_ah_nomem),
                            &ahstack->ah_dropper);
                        BUMP_MIB(ira->ira_ill->ill_ip_mib, ipIfStatsInDiscards);
                        return (NULL);
                }
        }

        /*
         * Insert pseudo header:
         * [IP, ULP] => [IP, AH, ICV] -> ULP
         */
        if (ira->ira_flags & IRAF_IS_IPV4) {
                phdr_mp = ah_process_ip_options_v4(data_mp, assoc,
                    &length_to_skip, assoc->ipsa_mac_len, B_FALSE, ahstack);
        } else {
                phdr_mp = ah_process_ip_options_v6(data_mp, assoc,
                    &length_to_skip, assoc->ipsa_mac_len, B_FALSE, ahstack);
        }

        if (phdr_mp == NULL) {
                IP_AH_BUMP_STAT(ipss, in_discards);
                ip_drop_packet(data_mp, B_TRUE, ira->ira_ill,
                    ((ira->ira_flags & IRAF_IS_IPV4) ?
                    DROPPER(ipss, ipds_ah_bad_v4_opts) :
                    DROPPER(ipss, ipds_ah_bad_v6_hdrs)),
                    &ahstack->ah_dropper);
                BUMP_MIB(ira->ira_ill->ill_ip_mib, ipIfStatsInDiscards);
                return (NULL);
        }

        phdr_mp->b_cont = data_mp;
        data_mp->b_rptr += length_to_skip;
        data_mp = phdr_mp;

        /* submit request to KCF */
        return (ah_submit_req_inbound(data_mp, ira, length_to_skip, ah_offset,
            assoc));
}

/*
 * Invoked after processing of an inbound packet by the
 * kernel crypto framework. Called by ah_submit_req() for a sync request,
 * or by the kcf callback for an async request.
 * Returns NULL if the mblk chain is consumed.
 */
static mblk_t *
ah_auth_in_done(mblk_t *phdr_mp, ip_recv_attr_t *ira, ipsec_crypto_t *ic)
{
        ipha_t *ipha;
        uint_t ah_offset = 0;
        mblk_t *mp;
        int align_len, newpos;
        ah_t *ah;
        uint32_t length;
        uint32_t *dest32;
        uint8_t *dest;
        boolean_t isv4;
        ip6_t *ip6h;
        uint_t icv_len;
        ipsa_t *assoc;
        kstat_named_t *counter;
        netstack_t      *ns = ira->ira_ill->ill_ipst->ips_netstack;
        ipsecah_stack_t *ahstack = ns->netstack_ipsecah;
        ipsec_stack_t   *ipss = ns->netstack_ipsec;

        isv4 = (ira->ira_flags & IRAF_IS_IPV4);
        assoc = ira->ira_ipsec_ah_sa;
        icv_len = (uint_t)ic->ic_crypto_mac.cd_raw.iov_len;

        if (phdr_mp == NULL) {
                ip_drop_packet(phdr_mp, B_TRUE, ira->ira_ill,
                    DROPPER(ipss, ipds_ah_nomem),
                    &ahstack->ah_dropper);
                BUMP_MIB(ira->ira_ill->ill_ip_mib, ipIfStatsInDiscards);
                return (NULL);
        }

        mp = phdr_mp->b_cont;
        if (mp == NULL) {
                ip_drop_packet(phdr_mp, B_TRUE, ira->ira_ill,
                    DROPPER(ipss, ipds_ah_nomem),
                    &ahstack->ah_dropper);
                BUMP_MIB(ira->ira_ill->ill_ip_mib, ipIfStatsInDiscards);
                return (NULL);
        }
        mp->b_rptr -= ic->ic_skip_len;

        ah_set_usetime(assoc, B_TRUE);

        if (isv4) {
                ipha = (ipha_t *)mp->b_rptr;
                ah_offset = ipha->ipha_version_and_hdr_length -
                    (uint8_t)((IP_VERSION << 4));
                ah_offset <<= 2;
                align_len = P2ALIGN(icv_len + IPV4_PADDING_ALIGN - 1,
                    IPV4_PADDING_ALIGN);
        } else {
                ip6h = (ip6_t *)mp->b_rptr;
                ah_offset = ipsec_ah_get_hdr_size_v6(mp, B_TRUE);
                ASSERT((mp->b_wptr - mp->b_rptr) >= ah_offset);
                align_len = P2ALIGN(icv_len + IPV6_PADDING_ALIGN - 1,
                    IPV6_PADDING_ALIGN);
        }

        ah = (ah_t *)(mp->b_rptr + ah_offset);
        newpos = sizeof (ah_t) + align_len;

        /*
         * We get here only when authentication passed.
         */

        ah3dbg(ahstack, ("AH succeeded, checking replay\n"));
        AH_BUMP_STAT(ahstack, good_auth);

        if (!sadb_replay_check(assoc, ah->ah_replay)) {
                int af;
                void *addr;

                if (isv4) {
                        addr = &ipha->ipha_dst;
                        af = AF_INET;
                } else {
                        addr = &ip6h->ip6_dst;
                        af = AF_INET6;
                }

                /*
                 * Log the event. As of now we print out an event.
                 * Do not print the replay failure number, or else
                 * syslog cannot collate the error messages.  Printing
                 * the replay number that failed (or printing to the
                 * console) opens a denial-of-service attack.
                 */
                AH_BUMP_STAT(ahstack, replay_failures);
                ipsec_assocfailure(info.mi_idnum, 0, 0,
                    SL_ERROR | SL_WARN,
                    "Replay failed for AH spi %x, dst_addr %s",
                    assoc->ipsa_spi, addr, af, ahstack->ipsecah_netstack);
                counter = DROPPER(ipss, ipds_ah_replay);
                goto ah_in_discard;
        }

        /*
         * We need to remove the AH header from the original
         * datagram. Best way to do this is to move the pre-AH headers
         * forward in the (relatively simple) IPv4 case.  In IPv6, it's
         * a bit more complicated because of IPv6's next-header chaining,
         * but it's doable.
         */
        if (isv4) {
                /*
                 * Assign the right protocol, adjust the length as we
                 * are removing the AH header and adjust the checksum to
                 * account for the protocol and length.
                 */
                length = ntohs(ipha->ipha_length);
                if (!ah_age_bytes(assoc, length, B_TRUE)) {
                        /* The ipsa has hit hard expiration, LOG and AUDIT. */
                        ipsec_assocfailure(info.mi_idnum, 0, 0,
                            SL_ERROR | SL_WARN,
                            "AH Association 0x%x, dst %s had bytes expire.\n",
                            assoc->ipsa_spi, assoc->ipsa_dstaddr,
                            AF_INET, ahstack->ipsecah_netstack);
                        AH_BUMP_STAT(ahstack, bytes_expired);
                        counter = DROPPER(ipss, ipds_ah_bytes_expire);
                        goto ah_in_discard;
                }
                ipha->ipha_protocol = ah->ah_nexthdr;
                length -= newpos;

                ipha->ipha_length = htons((uint16_t)length);
                ipha->ipha_hdr_checksum = 0;
                ipha->ipha_hdr_checksum = (uint16_t)ip_csum_hdr(ipha);
        } else {
                uchar_t *whereptr;
                int hdrlen;
                uint8_t *nexthdr;
                ip6_hbh_t *hbhhdr;
                ip6_dest_t *dsthdr;
                ip6_rthdr0_t *rthdr;

                /*
                 * Make phdr_mp hold until the AH header and make
                 * mp hold everything past AH header.
                 */
                length = ntohs(ip6h->ip6_plen);
                if (!ah_age_bytes(assoc, length + sizeof (ip6_t), B_TRUE)) {
                        /* The ipsa has hit hard expiration, LOG and AUDIT. */
                        ipsec_assocfailure(info.mi_idnum, 0, 0,
                            SL_ERROR | SL_WARN,
                            "AH Association 0x%x, dst %s had bytes "
                            "expire.\n", assoc->ipsa_spi, &ip6h->ip6_dst,
                            AF_INET6, ahstack->ipsecah_netstack);
                        AH_BUMP_STAT(ahstack, bytes_expired);
                        counter = DROPPER(ipss, ipds_ah_bytes_expire);
                        goto ah_in_discard;
                }

                /*
                 * Update the next header field of the header preceding
                 * AH with the next header field of AH. Start with the
                 * IPv6 header and proceed with the extension headers
                 * until we find what we're looking for.
                 */
                nexthdr = &ip6h->ip6_nxt;
                whereptr =  (uchar_t *)ip6h;
                hdrlen = sizeof (ip6_t);

                while (*nexthdr != IPPROTO_AH) {
                        whereptr += hdrlen;
                        /* Assume IP has already stripped it */
                        ASSERT(*nexthdr != IPPROTO_FRAGMENT);
                        switch (*nexthdr) {
                        case IPPROTO_HOPOPTS:
                                hbhhdr = (ip6_hbh_t *)whereptr;
                                nexthdr = &hbhhdr->ip6h_nxt;
                                hdrlen = 8 * (hbhhdr->ip6h_len + 1);
                                break;
                        case IPPROTO_DSTOPTS:
                                dsthdr = (ip6_dest_t *)whereptr;
                                nexthdr = &dsthdr->ip6d_nxt;
                                hdrlen = 8 * (dsthdr->ip6d_len + 1);
                                break;
                        case IPPROTO_ROUTING:
                                rthdr = (ip6_rthdr0_t *)whereptr;
                                nexthdr = &rthdr->ip6r0_nxt;
                                hdrlen = 8 * (rthdr->ip6r0_len + 1);
                                break;
                        }
                }
                *nexthdr = ah->ah_nexthdr;
                length -= newpos;
                ip6h->ip6_plen = htons((uint16_t)length);
        }

        /* Now that we've fixed the IP header, move it forward. */
        mp->b_rptr += newpos;
        if (IS_P2ALIGNED(mp->b_rptr, sizeof (uint32_t))) {
                dest32 = (uint32_t *)(mp->b_rptr + ah_offset);
                while (--dest32 >= (uint32_t *)mp->b_rptr)
                        *dest32 = *(dest32 - (newpos >> 2));
        } else {
                dest = mp->b_rptr + ah_offset;
                while (--dest >= mp->b_rptr)
                        *dest = *(dest - newpos);
        }
        freeb(phdr_mp);

        /*
         * If SA is labelled, use its label, else inherit the label
         */
        if (is_system_labeled() && (assoc->ipsa_tsl != NULL)) {
                if (!ip_recv_attr_replace_label(ira, assoc->ipsa_tsl)) {
                        ip_drop_packet(mp, B_TRUE, ira->ira_ill,
                            DROPPER(ipss, ipds_ah_nomem), &ahstack->ah_dropper);
                        BUMP_MIB(ira->ira_ill->ill_ip_mib, ipIfStatsInDiscards);
                        return (NULL);
                }
        }

        if (assoc->ipsa_state == IPSA_STATE_IDLE) {
                /*
                 * Cluster buffering case.  Tell caller that we're
                 * handling the packet.
                 */
                sadb_buf_pkt(assoc, mp, ira);
                return (NULL);
        }

        return (mp);

ah_in_discard:
        IP_AH_BUMP_STAT(ipss, in_discards);
        ip_drop_packet(phdr_mp, B_TRUE, ira->ira_ill, counter,
            &ahstack->ah_dropper);
        BUMP_MIB(ira->ira_ill->ill_ip_mib, ipIfStatsInDiscards);
        return (NULL);
}

/*
 * Invoked after processing of an outbound packet by the
 * kernel crypto framework, either by ah_submit_req() for a request
 * executed syncrhonously, or by the KEF callback for a request
 * executed asynchronously.
 */
static mblk_t *
ah_auth_out_done(mblk_t *phdr_mp, ip_xmit_attr_t *ixa, ipsec_crypto_t *ic)
{
        mblk_t *mp;
        int align_len;
        uint32_t hdrs_length;
        uchar_t *ptr;
        uint32_t length;
        boolean_t isv4;
        size_t icv_len;
        netstack_t      *ns = ixa->ixa_ipst->ips_netstack;
        ipsecah_stack_t *ahstack = ns->netstack_ipsecah;
        ipsec_stack_t   *ipss = ns->netstack_ipsec;
        ill_t           *ill = ixa->ixa_nce->nce_ill;

        isv4 = (ixa->ixa_flags & IXAF_IS_IPV4);
        icv_len = ic->ic_crypto_mac.cd_raw.iov_len;

        mp = phdr_mp->b_cont;
        if (mp == NULL) {
                ip_drop_packet(phdr_mp, B_FALSE, ill,
                    DROPPER(ipss, ipds_ah_nomem),
                    &ahstack->ah_dropper);
                BUMP_MIB(ill->ill_ip_mib, ipIfStatsOutDiscards);
                return (NULL);
        }
        mp->b_rptr -= ic->ic_skip_len;

        ASSERT(ixa->ixa_flags & IXAF_IPSEC_SECURE);
        ASSERT(ixa->ixa_ipsec_ah_sa != NULL);
        ah_set_usetime(ixa->ixa_ipsec_ah_sa, B_FALSE);

        if (isv4) {
                ipha_t *ipha;
                ipha_t *nipha;

                ipha = (ipha_t *)mp->b_rptr;
                hdrs_length = ipha->ipha_version_and_hdr_length -
                    (uint8_t)((IP_VERSION << 4));
                hdrs_length <<= 2;
                align_len = P2ALIGN(icv_len + IPV4_PADDING_ALIGN - 1,
                    IPV4_PADDING_ALIGN);
                /*
                 * phdr_mp must have the right amount of space for the
                 * combined IP and AH header. Copy the IP header and
                 * the ack_data onto AH. Note that the AH header was
                 * already formed before the ICV calculation and hence
                 * you don't have to copy it here.
                 */
                bcopy(mp->b_rptr, phdr_mp->b_rptr, hdrs_length);

                ptr = phdr_mp->b_rptr + hdrs_length + sizeof (ah_t);
                bcopy(phdr_mp->b_wptr, ptr, icv_len);

                /*
                 * Compute the new header checksum as we are assigning
                 * IPPROTO_AH and adjusting the length here.
                 */
                nipha = (ipha_t *)phdr_mp->b_rptr;

                nipha->ipha_protocol = IPPROTO_AH;
                length = ntohs(nipha->ipha_length);
                length += (sizeof (ah_t) + align_len);
                nipha->ipha_length = htons((uint16_t)length);
                nipha->ipha_hdr_checksum = 0;
                nipha->ipha_hdr_checksum = (uint16_t)ip_csum_hdr(nipha);
        } else {
                ip6_t *ip6h;
                ip6_t *nip6h;
                uint_t ah_offset;

                ip6h = (ip6_t *)mp->b_rptr;
                nip6h = (ip6_t *)phdr_mp->b_rptr;
                align_len = P2ALIGN(icv_len + IPV6_PADDING_ALIGN - 1,
                    IPV6_PADDING_ALIGN);
                /*
                 * phdr_mp must have the right amount of space for the
                 * combined IP and AH header. Copy the IP header with
                 * options into the pseudo header. When we constructed
                 * a pseudo header, we did not copy some of the mutable
                 * fields. We do it now by calling ah_fix_phdr_v6()
                 * with the last argument B_TRUE. It returns the
                 * ah_offset into the pseudo header.
                 */

                bcopy(ip6h, nip6h, IPV6_HDR_LEN);
                ah_offset = ah_fix_phdr_v6(nip6h, ip6h, B_TRUE, B_TRUE);
                ASSERT(ah_offset != 0);
                /*
                 * phdr_mp can hold exactly the whole IP header with options
                 * plus the AH header also. Thus subtracting the AH header's
                 * size should give exactly how much of the original header
                 * should be skipped.
                 */
                hdrs_length = (phdr_mp->b_wptr - phdr_mp->b_rptr) -
                    sizeof (ah_t) - icv_len;
                bcopy(phdr_mp->b_wptr, ((uint8_t *)nip6h + ah_offset +
                    sizeof (ah_t)), icv_len);
                length = ntohs(nip6h->ip6_plen);
                length += (sizeof (ah_t) + align_len);
                nip6h->ip6_plen = htons((uint16_t)length);
        }

        /* Skip the original IP header */
        mp->b_rptr += hdrs_length;
        if (mp->b_rptr == mp->b_wptr) {
                phdr_mp->b_cont = mp->b_cont;
                freeb(mp);
        }

        return (phdr_mp);
}

/* Refactor me */
/*
 * Wrapper to allow IP to trigger an AH association failure message
 * during SA inbound selection.
 */
void
ipsecah_in_assocfailure(mblk_t *mp, char level, ushort_t sl, char *fmt,
    uint32_t spi, void *addr, int af, ip_recv_attr_t *ira)
{
        netstack_t      *ns = ira->ira_ill->ill_ipst->ips_netstack;
        ipsecah_stack_t *ahstack = ns->netstack_ipsecah;
        ipsec_stack_t   *ipss = ns->netstack_ipsec;

        if (ahstack->ipsecah_log_unknown_spi) {
                ipsec_assocfailure(info.mi_idnum, 0, level, sl, fmt, spi,
                    addr, af, ahstack->ipsecah_netstack);
        }

        ip_drop_packet(mp, B_TRUE, ira->ira_ill,
            DROPPER(ipss, ipds_ah_no_sa),
            &ahstack->ah_dropper);
}

/*
 * Initialize the AH input and output processing functions.
 */
void
ipsecah_init_funcs(ipsa_t *sa)
{
        if (sa->ipsa_output_func == NULL)
                sa->ipsa_output_func = ah_outbound;
        if (sa->ipsa_input_func == NULL)
                sa->ipsa_input_func = ah_inbound;
}