Expand PMF_FN_* macros.

[netbsd-mini2440.git] / sys / netipsec / xform_esp.c

/*      $NetBSD: xform_esp.c,v 1.21 2009/03/18 17:06:52 cegger Exp $    */
/*      $FreeBSD: src/sys/netipsec/xform_esp.c,v 1.2.2.1 2003/01/24 05:11:36 sam Exp $  */
/*      $OpenBSD: ip_esp.c,v 1.69 2001/06/26 06:18:59 angelos Exp $ */

/*
 * The authors of this code are John Ioannidis (ji@tla.org),
 * Angelos D. Keromytis (kermit@csd.uch.gr) and
 * Niels Provos (provos@physnet.uni-hamburg.de).
 *
 * The original version of this code was written by John Ioannidis
 * for BSD/OS in Athens, Greece, in November 1995.
 *
 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
 * by Angelos D. Keromytis.
 *
 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
 * and Niels Provos.
 *
 * Additional features in 1999 by Angelos D. Keromytis.
 *
 * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
 * Angelos D. Keromytis and Niels Provos.
 * Copyright (c) 2001 Angelos D. Keromytis.
 *
 * Permission to use, copy, and modify this software with or without fee
 * is hereby granted, provided that this entire notice is included in
 * all copies of any software which is or includes a copy or
 * modification of this software.
 * You may use this code under the GNU public license if you so wish. Please
 * contribute changes back to the authors under this freer than GPL license
 * so that we may further the use of strong encryption without limitations to
 * all.
 *
 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
 * PURPOSE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: xform_esp.c,v 1.21 2009/03/18 17:06:52 cegger Exp $");

#include "opt_inet.h"
#ifdef __FreeBSD__
#include "opt_inet6.h"
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/syslog.h>
#include <sys/kernel.h>
/*#include <sys/random.h>*/
#include <sys/sysctl.h>

#include <net/if.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_ecn.h>
#include <netinet/ip6.h>

#include <net/route.h>
#include <netipsec/ipsec.h>
#include <netipsec/ipsec_private.h>
#include <netipsec/ah.h>
#include <netipsec/ah_var.h>
#include <netipsec/esp.h>
#include <netipsec/esp_var.h>
#include <netipsec/xform.h>

#ifdef INET6
#include <netinet6/ip6_var.h>
#include <netipsec/ipsec6.h>
#  ifdef __FreeBSD__
#  include <netinet6/ip6_ecn.h>
#  endif
#endif

#include <netipsec/key.h>
#include <netipsec/key_debug.h>

#include <netipsec/ipsec_osdep.h>

#include <opencrypto/cryptodev.h>
#include <opencrypto/xform.h>

percpu_t *espstat_percpu;

int     esp_enable = 1;

#ifdef __FreeBSD__
SYSCTL_DECL(_net_inet_esp);
SYSCTL_INT(_net_inet_esp, OID_AUTO,
        esp_enable,     CTLFLAG_RW,     &esp_enable,    0, "");
SYSCTL_STRUCT(_net_inet_esp, IPSECCTL_STATS,
        stats,          CTLFLAG_RD,     &espstat,       espstat, "");
#endif /* __FreeBSD__ */

static  int esp_max_ivlen;              /* max iv length over all algorithms */

static int esp_input_cb(struct cryptop *op);
static int esp_output_cb(struct cryptop *crp);

/*
 * NB: this is public for use by the PF_KEY support.
 * NB: if you add support here; be sure to add code to esp_attach below!
 */
struct enc_xform *
esp_algorithm_lookup(int alg)
{
        if (alg >= ESP_ALG_MAX)
                return NULL;
        switch (alg) {
        case SADB_EALG_DESCBC:
                return &enc_xform_des;
        case SADB_EALG_3DESCBC:
                return &enc_xform_3des;
        case SADB_X_EALG_AES:
                return &enc_xform_rijndael128;
        case SADB_X_EALG_BLOWFISHCBC:
                return &enc_xform_blf;
        case SADB_X_EALG_CAST128CBC:
                return &enc_xform_cast5;
        case SADB_X_EALG_SKIPJACK:
                return &enc_xform_skipjack;
        case SADB_EALG_NULL:
                return &enc_xform_null;
        }
        return NULL;
}

size_t
esp_hdrsiz(struct secasvar *sav)
{
        size_t size;

        if (sav != NULL) {
                /*XXX not right for null algorithm--does it matter??*/
                IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
                        ("esp_hdrsiz: SA with null xform"));
                if (sav->flags & SADB_X_EXT_OLD)
                        size = sizeof (struct esp);
                else
                        size = sizeof (struct newesp);
                size += sav->tdb_encalgxform->blocksize + 9;
                /*XXX need alg check???*/
                if (sav->tdb_authalgxform != NULL && sav->replay)
                        size += ah_hdrsiz(sav);
        } else {
                /*
                 *   base header size
                 * + max iv length for CBC mode
                 * + max pad length
                 * + sizeof (pad length field)
                 * + sizeof (next header field)
                 * + max icv supported.
                 */
                size = sizeof (struct newesp) + esp_max_ivlen + 9 + 16;
        }
        return size;
}

/*
 * esp_init() is called when an SPI is being set up.
 */
static int
esp_init(struct secasvar *sav, struct xformsw *xsp)
{
        struct enc_xform *txform;
        struct cryptoini cria, crie;
        int keylen;
        int error;

        txform = esp_algorithm_lookup(sav->alg_enc);
        if (txform == NULL) {
                DPRINTF(("esp_init: unsupported encryption algorithm %d\n",
                        sav->alg_enc));
                return EINVAL;
        }
        if (sav->key_enc == NULL) {
                DPRINTF(("esp_init: no encoding key for %s algorithm\n",
                         txform->name));
                return EINVAL;
        }
        if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) {
                DPRINTF(("esp_init: 4-byte IV not supported with protocol\n"));
                return EINVAL;
        }
        keylen = _KEYLEN(sav->key_enc);
        if (txform->minkey > keylen || keylen > txform->maxkey) {
                DPRINTF(("esp_init: invalid key length %u, must be in "
                        "the range [%u..%u] for algorithm %s\n",
                        keylen, txform->minkey, txform->maxkey,
                        txform->name));
                return EINVAL;
        }

        /*
         * NB: The null xform needs a non-zero blocksize to keep the
         *      crypto code happy but if we use it to set ivlen then
         *      the ESP header will be processed incorrectly.  The
         *      compromise is to force it to zero here.
         */
        sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize);
        sav->iv = malloc(sav->ivlen, M_SECA, M_WAITOK);
        if (sav->iv == NULL) {
                DPRINTF(("esp_init: no memory for IV\n"));
                return EINVAL;
        }
        key_randomfill(sav->iv, sav->ivlen);    /*XXX*/

        /*
         * Setup AH-related state.
         */
        if (sav->alg_auth != 0) {
                error = ah_init0(sav, xsp, &cria);
                if (error)
                        return error;
        }

        /* NB: override anything set in ah_init0 */
        sav->tdb_xform = xsp;
        sav->tdb_encalgxform = txform;

        /* Initialize crypto session. */
        memset(&crie, 0, sizeof (crie));
        crie.cri_alg = sav->tdb_encalgxform->type;
        crie.cri_klen = _KEYBITS(sav->key_enc);
        crie.cri_key = _KEYBUF(sav->key_enc);
        /* XXX Rounds ? */

        mutex_spin_enter(&crypto_mtx);
        if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
                /* init both auth & enc */
                crie.cri_next = &cria;
                error = crypto_newsession(&sav->tdb_cryptoid,
                                          &crie, crypto_support);
        } else if (sav->tdb_encalgxform) {
                error = crypto_newsession(&sav->tdb_cryptoid,
                                          &crie, crypto_support);
        } else if (sav->tdb_authalgxform) {
                error = crypto_newsession(&sav->tdb_cryptoid,
                                          &cria, crypto_support);
        } else {
                /* XXX cannot happen? */
                DPRINTF(("esp_init: no encoding OR authentication xform!\n"));
                error = EINVAL;
        }
        mutex_spin_exit(&crypto_mtx);
        return error;
}

/*
 * Paranoia.
 */
static int
esp_zeroize(struct secasvar *sav)
{
        /* NB: ah_zerorize free's the crypto session state */
        int error = ah_zeroize(sav);

        if (sav->key_enc)
                memset(_KEYBUF(sav->key_enc), 0, _KEYLEN(sav->key_enc));
        /* NB: sav->iv is freed elsewhere, even though we malloc it! */
        sav->tdb_encalgxform = NULL;
        sav->tdb_xform = NULL;
        return error;
}

/*
 * ESP input processing, called (eventually) through the protocol switch.
 */
static int
esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
{
        struct auth_hash *esph;
        struct enc_xform *espx;
        struct tdb_ident *tdbi;
        struct tdb_crypto *tc;
        int plen, alen, hlen;
        struct m_tag *mtag;
        struct newesp *esp;

        struct cryptodesc *crde;
        struct cryptop *crp;

        IPSEC_SPLASSERT_SOFTNET("esp_input");

        IPSEC_ASSERT(sav != NULL, ("esp_input: null SA"));
        IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
                ("esp_input: null encoding xform"));
        IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0,
                ("esp_input: misaligned packet, skip %u pkt len %u",
                        skip, m->m_pkthdr.len));

        /* XXX don't pullup, just copy header */
        IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));

        esph = sav->tdb_authalgxform;
        espx = sav->tdb_encalgxform;

        /* Determine the ESP header length */
        if (sav->flags & SADB_X_EXT_OLD)
                hlen = sizeof (struct esp) + sav->ivlen;
        else
                hlen = sizeof (struct newesp) + sav->ivlen;
        /* Authenticator hash size */
        alen = esph ? AH_HMAC_HASHLEN : 0;

        /*
         * Verify payload length is multiple of encryption algorithm
         * block size.
         *
         * NB: This works for the null algorithm because the blocksize
         *     is 4 and all packets must be 4-byte aligned regardless
         *     of the algorithm.
         */
        plen = m->m_pkthdr.len - (skip + hlen + alen);
        if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
                DPRINTF(("esp_input: "
                    "payload of %d octets not a multiple of %d octets,"
                    "  SA %s/%08lx\n",
                    plen, espx->blocksize,
                    ipsec_address(&sav->sah->saidx.dst),
                    (u_long) ntohl(sav->spi)));
                ESP_STATINC(ESP_STAT_BADILEN);
                m_freem(m);
                return EINVAL;
        }

        /*
         * Check sequence number.
         */
        if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
                DPRINTF(("esp_input: packet replay check for %s\n",
                    ipsec_logsastr(sav)));      /*XXX*/
                ESP_STATINC(ESP_STAT_REPLAY);
                m_freem(m);
                return ENOBUFS;         /*XXX*/
        }

        /* Update the counters */
        ESP_STATADD(ESP_STAT_IBYTES, m->m_pkthdr.len - skip - hlen - alen);

        /* Find out if we've already done crypto */
        for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
             mtag != NULL;
             mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
                tdbi = (struct tdb_ident *) (mtag + 1);
                if (tdbi->proto == sav->sah->saidx.proto &&
                    tdbi->spi == sav->spi &&
                    !memcmp(&tdbi->dst, &sav->sah->saidx.dst,
                          sizeof(union sockaddr_union)))
                        break;
        }

        /* Get crypto descriptors */
        crp = crypto_getreq(esph && espx ? 2 : 1);
        if (crp == NULL) {
                DPRINTF(("esp_input: failed to acquire crypto descriptors\n"));
                ESP_STATINC(ESP_STAT_CRYPTO);
                m_freem(m);
                return ENOBUFS;
        }

        /* Get IPsec-specific opaque pointer */
        if (esph == NULL || mtag != NULL)
                tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
                    M_XDATA, M_NOWAIT|M_ZERO);
        else
                tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen,
                    M_XDATA, M_NOWAIT|M_ZERO);
        if (tc == NULL) {
                crypto_freereq(crp);
                DPRINTF(("esp_input: failed to allocate tdb_crypto\n"));
                ESP_STATINC(ESP_STAT_CRYPTO);
                m_freem(m);
                return ENOBUFS;
        }

        tc->tc_ptr = mtag;

        if (esph) {
                struct cryptodesc *crda = crp->crp_desc;

                IPSEC_ASSERT(crda != NULL, ("esp_input: null ah crypto descriptor"));

                /* Authentication descriptor */
                crda->crd_skip = skip;
                crda->crd_len = m->m_pkthdr.len - (skip + alen);
                crda->crd_inject = m->m_pkthdr.len - alen;

                crda->crd_alg = esph->type;
                crda->crd_key = _KEYBUF(sav->key_auth);
                crda->crd_klen = _KEYBITS(sav->key_auth);

                /* Copy the authenticator */
                if (mtag == NULL)
                        m_copydata(m, m->m_pkthdr.len - alen, alen,
                                      (tc + 1));

                /* Chain authentication request */
                crde = crda->crd_next;
        } else {
                crde = crp->crp_desc;
        }

        /* Crypto operation descriptor */
        crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
        crp->crp_flags = CRYPTO_F_IMBUF;
        crp->crp_buf = m;
        crp->crp_callback = esp_input_cb;
        crp->crp_sid = sav->tdb_cryptoid;
        crp->crp_opaque = tc;

        /* These are passed as-is to the callback */
        tc->tc_spi = sav->spi;
        tc->tc_dst = sav->sah->saidx.dst;
        tc->tc_proto = sav->sah->saidx.proto;
        tc->tc_protoff = protoff;
        tc->tc_skip = skip;

        /* Decryption descriptor */
        if (espx) {
                IPSEC_ASSERT(crde != NULL, ("esp_input: null esp crypto descriptor"));
                crde->crd_skip = skip + hlen;
                crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
                crde->crd_inject = skip + hlen - sav->ivlen;

                crde->crd_alg = espx->type;
                crde->crd_key = _KEYBUF(sav->key_enc);
                crde->crd_klen = _KEYBITS(sav->key_enc);
                /* XXX Rounds ? */
        }

        if (mtag == NULL)
                return crypto_dispatch(crp);
        else
                return esp_input_cb(crp);
}

#ifdef INET6
#define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do {              \
        if (saidx->dst.sa.sa_family == AF_INET6) {                           \
                error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
        } else {                                                             \
                error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
        }                                                                    \
} while (0)
#else
#define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag)                   \
        (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
#endif

/*
 * ESP input callback from the crypto driver.
 */
static int
esp_input_cb(struct cryptop *crp)
{
        u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN];
        int s, hlen, skip, protoff, error;
        struct mbuf *m;
        struct cryptodesc *crd;
        struct auth_hash *esph;
        struct enc_xform *espx;
        struct tdb_crypto *tc;
        struct m_tag *mtag;
        struct secasvar *sav;
        struct secasindex *saidx;
        void *ptr;
        u_int16_t dport = 0;
        u_int16_t sport = 0;
#ifdef IPSEC_NAT_T
        struct m_tag * tag = NULL;
#endif

        crd = crp->crp_desc;
        IPSEC_ASSERT(crd != NULL, ("esp_input_cb: null crypto descriptor!"));

        tc = (struct tdb_crypto *) crp->crp_opaque;
        IPSEC_ASSERT(tc != NULL, ("esp_input_cb: null opaque crypto data area!"));
        skip = tc->tc_skip;
        protoff = tc->tc_protoff;
        mtag = (struct m_tag *) tc->tc_ptr;
        m = (struct mbuf *) crp->crp_buf;

#ifdef IPSEC_NAT_T
        /* find the source port for NAT-T */
        if ((tag = m_tag_find(m, PACKET_TAG_IPSEC_NAT_T_PORTS, NULL))) {
                sport = ((u_int16_t *)(tag + 1))[0];
                dport = ((u_int16_t *)(tag + 1))[1];
        }
#endif

        s = splsoftnet();

        sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, sport, dport);
        if (sav == NULL) {
                ESP_STATINC(ESP_STAT_NOTDB);
                DPRINTF(("esp_input_cb: SA expired while in crypto "
                    "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst),
                    (u_long) ntohl(tc->tc_spi), tc->tc_proto));
                error = ENOBUFS;                /*XXX*/
                goto bad;
        }

        saidx = &sav->sah->saidx;
        IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
                saidx->dst.sa.sa_family == AF_INET6,
                ("ah_input_cb: unexpected protocol family %u",
                 saidx->dst.sa.sa_family));

        esph = sav->tdb_authalgxform;
        espx = sav->tdb_encalgxform;

        /* Check for crypto errors */
        if (crp->crp_etype) {
                /* Reset the session ID */
                if (sav->tdb_cryptoid != 0)
                        sav->tdb_cryptoid = crp->crp_sid;

                if (crp->crp_etype == EAGAIN) {
                        KEY_FREESAV(&sav);
                        splx(s);
                        return crypto_dispatch(crp);
                }

                ESP_STATINC(ESP_STAT_NOXFORM);
                DPRINTF(("esp_input_cb: crypto error %d\n", crp->crp_etype));
                error = crp->crp_etype;
                goto bad;
        }

        /* Shouldn't happen... */
        if (m == NULL) {
                ESP_STATINC(ESP_STAT_CRYPTO);
                DPRINTF(("esp_input_cb: bogus returned buffer from crypto\n"));
                error = EINVAL;
                goto bad;
        }
        ESP_STATINC(ESP_STAT_HIST + sav->alg_enc);

        /* If authentication was performed, check now. */
        if (esph != NULL) {
                /*
                 * If we have a tag, it means an IPsec-aware NIC did
                 * the verification for us.  Otherwise we need to
                 * check the authentication calculation.
                 */
                AH_STATINC(AH_STAT_HIST + sav->alg_auth);
                if (mtag == NULL) {
                        /* Copy the authenticator from the packet */
                        m_copydata(m, m->m_pkthdr.len - esph->authsize,
                                esph->authsize, aalg);

                        ptr = (tc + 1);

                        /* Verify authenticator */
                        if (memcmp(ptr, aalg, esph->authsize) != 0) {
                                DPRINTF(("esp_input_cb: "
                    "authentication hash mismatch for packet in SA %s/%08lx\n",
                                    ipsec_address(&saidx->dst),
                                    (u_long) ntohl(sav->spi)));
                                ESP_STATINC(ESP_STAT_BADAUTH);
                                error = EACCES;
                                goto bad;
                        }
                }

                /* Remove trailing authenticator */
                m_adj(m, -(esph->authsize));
        }

        /* Release the crypto descriptors */
        free(tc, M_XDATA), tc = NULL;
        crypto_freereq(crp), crp = NULL;

        /*
         * Packet is now decrypted.
         */
        m->m_flags |= M_DECRYPTED;

        /*
         * Update replay sequence number, if appropriate.
         */
        if (sav->replay) {
                u_int32_t seq;

                m_copydata(m, skip + offsetof(struct newesp, esp_seq),
                    sizeof (seq), &seq);
                if (ipsec_updatereplay(ntohl(seq), sav)) {
                        DPRINTF(("%s: packet replay check for %s\n", __func__,
                            ipsec_logsastr(sav)));
                        ESP_STATINC(ESP_STAT_REPLAY);
                        error = ENOBUFS;
                        goto bad;
                }
        }

        /* Determine the ESP header length */
        if (sav->flags & SADB_X_EXT_OLD)
                hlen = sizeof (struct esp) + sav->ivlen;
        else
                hlen = sizeof (struct newesp) + sav->ivlen;

        /* Remove the ESP header and IV from the mbuf. */
        error = m_striphdr(m, skip, hlen);
        if (error) {
                ESP_STATINC(ESP_STAT_HDROPS);
                DPRINTF(("esp_input_cb: bad mbuf chain, SA %s/%08lx\n",
                    ipsec_address(&sav->sah->saidx.dst),
                    (u_long) ntohl(sav->spi)));
                goto bad;
        }

        /* Save the last three bytes of decrypted data */
        m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);

        /* Verify pad length */
        if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
                ESP_STATINC(ESP_STAT_BADILEN);
                DPRINTF(("esp_input_cb: invalid padding length %d "
                         "for %u byte packet in SA %s/%08lx\n",
                         lastthree[1], m->m_pkthdr.len - skip,
                         ipsec_address(&sav->sah->saidx.dst),
                         (u_long) ntohl(sav->spi)));
                error = EINVAL;
                goto bad;
        }

        /* Verify correct decryption by checking the last padding bytes */
        if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
                if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
                        ESP_STATINC(ESP_STAT_BADENC);
                        DPRINTF(("esp_input_cb: decryption failed "
                                "for packet in SA %s/%08lx\n",
                                ipsec_address(&sav->sah->saidx.dst),
                                (u_long) ntohl(sav->spi)));
DPRINTF(("esp_input_cb: %x %x\n", lastthree[0], lastthree[1]));
                        error = EINVAL;
                        goto bad;
                }
        }

        /* Trim the mbuf chain to remove trailing authenticator and padding */
        m_adj(m, -(lastthree[1] + 2));

        /* Restore the Next Protocol field */
        m = m_copyback_cow(m, protoff, sizeof (u_int8_t), lastthree + 2,
                           M_DONTWAIT);

        if (m == NULL) {
                ESP_STATINC(ESP_STAT_CRYPTO);
                DPRINTF(("esp_input_cb: failed to allocate mbuf\n"));
                error = ENOBUFS;
                goto bad;
        }

        IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag);

        KEY_FREESAV(&sav);
        splx(s);
        return error;
bad:
        if (sav)
                KEY_FREESAV(&sav);
        splx(s);
        if (m != NULL)
                m_freem(m);
        if (tc != NULL)
                free(tc, M_XDATA);
        if (crp != NULL)
                crypto_freereq(crp);
        return error;
}

/*
 * ESP output routine, called by ipsec[46]_process_packet().
 */
static int
esp_output(
    struct mbuf *m,
    struct ipsecrequest *isr,
    struct mbuf **mp,
    int skip,
    int protoff
)
{
        struct enc_xform *espx;
        struct auth_hash *esph;
        int hlen, rlen, plen, padding, blks, alen, i, roff;
        struct mbuf *mo = (struct mbuf *) NULL;
        struct tdb_crypto *tc;
        struct secasvar *sav;
        struct secasindex *saidx;
        unsigned char *pad;
        u_int8_t prot;
        int error, maxpacketsize;

        struct cryptodesc *crde = NULL, *crda = NULL;
        struct cryptop *crp;

        IPSEC_SPLASSERT_SOFTNET("esp_output");

        sav = isr->sav;
        IPSEC_ASSERT(sav != NULL, ("esp_output: null SA"));
        esph = sav->tdb_authalgxform;
        espx = sav->tdb_encalgxform;
        IPSEC_ASSERT(espx != NULL, ("esp_output: null encoding xform"));

        if (sav->flags & SADB_X_EXT_OLD)
                hlen = sizeof (struct esp) + sav->ivlen;
        else
                hlen = sizeof (struct newesp) + sav->ivlen;

        rlen = m->m_pkthdr.len - skip;  /* Raw payload length. */
        /*
         * NB: The null encoding transform has a blocksize of 4
         *     so that headers are properly aligned.
         */
        blks = espx->blocksize;         /* IV blocksize */

        /* XXX clamp padding length a la KAME??? */
        padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
        plen = rlen + padding;          /* Padded payload length. */

        if (esph)
                alen = AH_HMAC_HASHLEN;
        else
                alen = 0;

        ESP_STATINC(ESP_STAT_OUTPUT);

        saidx = &sav->sah->saidx;
        /* Check for maximum packet size violations. */
        switch (saidx->dst.sa.sa_family) {
#ifdef INET
        case AF_INET:
                maxpacketsize = IP_MAXPACKET;
                break;
#endif /* INET */
#ifdef INET6
        case AF_INET6:
                maxpacketsize = IPV6_MAXPACKET;
                break;
#endif /* INET6 */
        default:
                DPRINTF(("esp_output: unknown/unsupported protocol "
                    "family %d, SA %s/%08lx\n",
                    saidx->dst.sa.sa_family, ipsec_address(&saidx->dst),
                    (u_long) ntohl(sav->spi)));
                ESP_STATINC(ESP_STAT_NOPF);
                error = EPFNOSUPPORT;
                goto bad;
        }
        if (skip + hlen + rlen + padding + alen > maxpacketsize) {
                DPRINTF(("esp_output: packet in SA %s/%08lx got too big "
                    "(len %u, max len %u)\n",
                    ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi),
                    skip + hlen + rlen + padding + alen, maxpacketsize));
                ESP_STATINC(ESP_STAT_TOOBIG);
                error = EMSGSIZE;
                goto bad;
        }

        /* Update the counters. */
        ESP_STATADD(ESP_STAT_OUTPUT, m->m_pkthdr.len - skip);

        m = m_clone(m);
        if (m == NULL) {
                DPRINTF(("esp_output: cannot clone mbuf chain, SA %s/%08lx\n",
                    ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
                ESP_STATINC(ESP_STAT_HDROPS);
                error = ENOBUFS;
                goto bad;
        }

        /* Inject ESP header. */
        mo = m_makespace(m, skip, hlen, &roff);
        if (mo == NULL) {
                DPRINTF(("esp_output: failed to inject %u byte ESP hdr for SA "
                    "%s/%08lx\n",
                    hlen, ipsec_address(&saidx->dst),
                    (u_long) ntohl(sav->spi)));
                ESP_STATINC(ESP_STAT_HDROPS);   /* XXX diffs from openbsd */
                error = ENOBUFS;
                goto bad;
        }

        /* Initialize ESP header. */
        memcpy(mtod(mo, char *) + roff, &sav->spi, sizeof(u_int32_t));
        if (sav->replay) {
                u_int32_t replay;

#ifdef IPSEC_DEBUG
                /* Emulate replay attack when ipsec_replay is TRUE. */
                if (!ipsec_replay)
#endif
                        sav->replay->count++;

                replay = htonl(sav->replay->count);
                bcopy(&replay,
                    mtod(mo,char *) + roff + sizeof(u_int32_t),
                    sizeof(u_int32_t));
        }

        /*
         * Add padding -- better to do it ourselves than use the crypto engine,
         * although if/when we support compression, we'd have to do that.
         */
        pad = (u_char *) m_pad(m, padding + alen);
        if (pad == NULL) {
                DPRINTF(("esp_output: m_pad failed for SA %s/%08lx\n",
                    ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
                m = NULL;               /* NB: free'd by m_pad */
                error = ENOBUFS;
                goto bad;
        }

        /*
         * Add padding: random, zero, or self-describing.
         * XXX catch unexpected setting
         */
        switch (sav->flags & SADB_X_EXT_PMASK) {
        case SADB_X_EXT_PRAND:
                (void) read_random(pad, padding - 2);
                break;
        case SADB_X_EXT_PZERO:
                memset(pad, 0, padding - 2);
                break;
        case SADB_X_EXT_PSEQ:
                for (i = 0; i < padding - 2; i++)
                        pad[i] = i+1;
                break;
        }

        /* Fix padding length and Next Protocol in padding itself. */
        pad[padding - 2] = padding - 2;
        m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);

        /* Fix Next Protocol in IPv4/IPv6 header. */
        prot = IPPROTO_ESP;
        m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);

        /* Get crypto descriptors. */
        crp = crypto_getreq(esph && espx ? 2 : 1);
        if (crp == NULL) {
                DPRINTF(("esp_output: failed to acquire crypto descriptors\n"));
                ESP_STATINC(ESP_STAT_CRYPTO);
                error = ENOBUFS;
                goto bad;
        }

        if (espx) {
                crde = crp->crp_desc;
                crda = crde->crd_next;

                /* Encryption descriptor. */
                crde->crd_skip = skip + hlen;
                crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
                crde->crd_flags = CRD_F_ENCRYPT;
                crde->crd_inject = skip + hlen - sav->ivlen;

                /* Encryption operation. */
                crde->crd_alg = espx->type;
                crde->crd_key = _KEYBUF(sav->key_enc);
                crde->crd_klen = _KEYBITS(sav->key_enc);
                /* XXX Rounds ? */
        } else
                crda = crp->crp_desc;

        /* IPsec-specific opaque crypto info. */
        tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
                M_XDATA, M_NOWAIT|M_ZERO);
        if (tc == NULL) {
                crypto_freereq(crp);
                DPRINTF(("esp_output: failed to allocate tdb_crypto\n"));
                ESP_STATINC(ESP_STAT_CRYPTO);
                error = ENOBUFS;
                goto bad;
        }

        /* Callback parameters */
        tc->tc_isr = isr;
        tc->tc_spi = sav->spi;
        tc->tc_dst = saidx->dst;
        tc->tc_proto = saidx->proto;

        /* Crypto operation descriptor. */
        crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
        crp->crp_flags = CRYPTO_F_IMBUF;
        crp->crp_buf = m;
        crp->crp_callback = esp_output_cb;
        crp->crp_opaque = tc;
        crp->crp_sid = sav->tdb_cryptoid;

        if (esph) {
                /* Authentication descriptor. */
                crda->crd_skip = skip;
                crda->crd_len = m->m_pkthdr.len - (skip + alen);
                crda->crd_inject = m->m_pkthdr.len - alen;

                /* Authentication operation. */
                crda->crd_alg = esph->type;
                crda->crd_key = _KEYBUF(sav->key_auth);
                crda->crd_klen = _KEYBITS(sav->key_auth);
        }

        return crypto_dispatch(crp);
bad:
        if (m)
                m_freem(m);
        return (error);
}

/*
 * ESP output callback from the crypto driver.
 */
static int
esp_output_cb(struct cryptop *crp)
{
        struct tdb_crypto *tc;
        struct ipsecrequest *isr;
        struct secasvar *sav;
        struct mbuf *m;
        int s, err, error;

        tc = (struct tdb_crypto *) crp->crp_opaque;
        IPSEC_ASSERT(tc != NULL, ("esp_output_cb: null opaque data area!"));
        m = (struct mbuf *) crp->crp_buf;

        s = splsoftnet();

        isr = tc->tc_isr;
        sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, 0, 0);
        if (sav == NULL) {
                ESP_STATINC(ESP_STAT_NOTDB);
                DPRINTF(("esp_output_cb: SA expired while in crypto "
                    "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst),
                    (u_long) ntohl(tc->tc_spi), tc->tc_proto));
                error = ENOBUFS;                /*XXX*/
                goto bad;
        }
        IPSEC_ASSERT(isr->sav == sav,
                ("esp_output_cb: SA changed was %p now %p\n", isr->sav, sav));

        /* Check for crypto errors. */
        if (crp->crp_etype) {
                /* Reset session ID. */
                if (sav->tdb_cryptoid != 0)
                        sav->tdb_cryptoid = crp->crp_sid;

                if (crp->crp_etype == EAGAIN) {
                        KEY_FREESAV(&sav);
                        splx(s);
                        return crypto_dispatch(crp);
                }

                ESP_STATINC(ESP_STAT_NOXFORM);
                DPRINTF(("esp_output_cb: crypto error %d\n", crp->crp_etype));
                error = crp->crp_etype;
                goto bad;
        }

        /* Shouldn't happen... */
        if (m == NULL) {
                ESP_STATINC(ESP_STAT_CRYPTO);
                DPRINTF(("esp_output_cb: bogus returned buffer from crypto\n"));
                error = EINVAL;
                goto bad;
        }
        ESP_STATINC(ESP_STAT_HIST + sav->alg_enc);
        if (sav->tdb_authalgxform != NULL)
                AH_STATINC(sav->alg_auth + sav->alg_auth);

        /* Release crypto descriptors. */
        free(tc, M_XDATA);
        crypto_freereq(crp);

#ifdef IPSEC_DEBUG
        /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
        if (ipsec_integrity) {
                static unsigned char ipseczeroes[AH_HMAC_HASHLEN];
                struct auth_hash *esph;

                /*
                 * Corrupt HMAC if we want to test integrity verification of
                 * the other side.
                 */
                esph = sav->tdb_authalgxform;
                if (esph !=  NULL) {
                        m_copyback(m, m->m_pkthdr.len - AH_HMAC_HASHLEN,
                            AH_HMAC_HASHLEN, ipseczeroes);
                }
        }
#endif

        /* NB: m is reclaimed by ipsec_process_done. */
        err = ipsec_process_done(m, isr);
        KEY_FREESAV(&sav);
        splx(s);
        return err;
bad:
        if (sav)
                KEY_FREESAV(&sav);
        splx(s);
        if (m)
                m_freem(m);
        free(tc, M_XDATA);
        crypto_freereq(crp);
        return error;
}

static struct xformsw esp_xformsw = {
        XF_ESP,         XFT_CONF|XFT_AUTH,      "IPsec ESP",
        esp_init,       esp_zeroize,            esp_input,
        esp_output,
        NULL,
};

INITFN void
esp_attach(void)
{

        espstat_percpu = percpu_alloc(sizeof(uint64_t) * ESP_NSTATS);

#define MAXIV(xform)                                    \
        if (xform.blocksize > esp_max_ivlen)            \
                esp_max_ivlen = xform.blocksize         \

        esp_max_ivlen = 0;
        MAXIV(enc_xform_des);           /* SADB_EALG_DESCBC */
        MAXIV(enc_xform_3des);          /* SADB_EALG_3DESCBC */
        MAXIV(enc_xform_rijndael128);   /* SADB_X_EALG_AES */
        MAXIV(enc_xform_blf);           /* SADB_X_EALG_BLOWFISHCBC */
        MAXIV(enc_xform_cast5);         /* SADB_X_EALG_CAST128CBC */
        MAXIV(enc_xform_skipjack);      /* SADB_X_EALG_SKIPJACK */
        MAXIV(enc_xform_null);          /* SADB_EALG_NULL */

        xform_register(&esp_xformsw);
#undef MAXIV
}
#ifdef __FreeBSD__
SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL)
#else
#endif