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

/*      $NetBSD: xform_ah.c,v 1.25 2009/03/18 17:06:52 cegger Exp $     */
/*      $FreeBSD: src/sys/netipsec/xform_ah.c,v 1.1.4.1 2003/01/24 05:11:36 sam Exp $   */
/*      $OpenBSD: ip_ah.c,v 1.63 2001/06/26 06:18:58 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 and Niklas Hallqvist.
 *
 * Copyright (c) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
 * Angelos D. Keromytis and Niels Provos.
 * Copyright (c) 1999 Niklas Hallqvist.
 * 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_ah.c,v 1.25 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/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/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>

/*
 * Return header size in bytes.  The old protocol did not support
 * the replay counter; the new protocol always includes the counter.
 */
#define HDRSIZE(sav) \
        (((sav)->flags & SADB_X_EXT_OLD) ? \
                sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t))
/*
 * Return authenticator size in bytes.  The old protocol is known
 * to use a fixed 16-byte authenticator.  The new algorithm gets
 * this size from the xform but is (currently) always 12.
 */
#define AUTHSIZE(sav) \
        ((sav->flags & SADB_X_EXT_OLD) ? 16 : (sav)->tdb_authalgxform->authsize)

percpu_t *ahstat_percpu;

int     ah_enable = 1;                  /* control flow of packets with AH */
int     ip4_ah_cleartos = 1;            /* clear ip_tos when doing AH calc */

#ifdef __FreeBSD__
SYSCTL_DECL(_net_inet_ah);
SYSCTL_INT(_net_inet_ah, OID_AUTO,
        ah_enable,      CTLFLAG_RW,     &ah_enable,     0, "");
SYSCTL_INT(_net_inet_ah, OID_AUTO,
        ah_cleartos,    CTLFLAG_RW,     &ip4_ah_cleartos,       0, "");
SYSCTL_STRUCT(_net_inet_ah, IPSECCTL_STATS,
        stats,          CTLFLAG_RD,     &ahstat,        ahstat, "");

#endif /* __FreeBSD__ */

static unsigned char ipseczeroes[256];  /* larger than an ip6 extension hdr */

static int ah_input_cb(struct cryptop*);
static int ah_output_cb(struct cryptop*);

/*
 * NB: this is public for use by the PF_KEY support.
 */
struct auth_hash *
ah_algorithm_lookup(int alg)
{
        if (alg >= AH_ALG_MAX)
                return NULL;
        switch (alg) {
        case SADB_X_AALG_NULL:
                return &auth_hash_null;
        case SADB_AALG_MD5HMAC:
                return &auth_hash_hmac_md5_96;
        case SADB_AALG_SHA1HMAC:
                return &auth_hash_hmac_sha1_96;
        case SADB_X_AALG_RIPEMD160HMAC:
                return &auth_hash_hmac_ripemd_160_96;
        case SADB_X_AALG_MD5:
                return &auth_hash_key_md5;
        case SADB_X_AALG_SHA:
                return &auth_hash_key_sha1;
        case SADB_X_AALG_SHA2_256:
                return &auth_hash_hmac_sha2_256;
        case SADB_X_AALG_SHA2_384:
                return &auth_hash_hmac_sha2_384;
        case SADB_X_AALG_SHA2_512:
                return &auth_hash_hmac_sha2_512;
        }
        return NULL;
}

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

        if (sav != NULL) {
                int authsize;
                IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
                        ("ah_hdrsiz: null xform"));
                /*XXX not right for null algorithm--does it matter??*/
                authsize = AUTHSIZE(sav);
                size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav);
        } else {
                /* default guess */
                size = sizeof (struct ah) + sizeof (u_int32_t) + 16;
        }
        return size;
}

/*
 * NB: public for use by esp_init.
 */
int
ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria)
{
        struct auth_hash *thash;
        int keylen;

        thash = ah_algorithm_lookup(sav->alg_auth);
        if (thash == NULL) {
                DPRINTF(("ah_init: unsupported authentication algorithm %u\n",
                        sav->alg_auth));
                return EINVAL;
        }
        /*
         * Verify the replay state block allocation is consistent with
         * the protocol type.  We check here so we can make assumptions
         * later during protocol processing.
         */
        /* NB: replay state is setup elsewhere (sigh) */
        if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) {
                DPRINTF(("ah_init: replay state block inconsistency, "
                        "%s algorithm %s replay state\n",
                        (sav->flags & SADB_X_EXT_OLD) ? "old" : "new",
                        sav->replay == NULL ? "without" : "with"));
                return EINVAL;
        }
        if (sav->key_auth == NULL) {
                DPRINTF(("ah_init: no authentication key for %s "
                        "algorithm\n", thash->name));
                return EINVAL;
        }
        keylen = _KEYLEN(sav->key_auth);
        if (keylen != thash->keysize && thash->keysize != 0) {
                DPRINTF(("ah_init: invalid keylength %d, algorithm "
                         "%s requires keysize %d\n",
                         keylen, thash->name, thash->keysize));
                return EINVAL;
        }

        sav->tdb_xform = xsp;
        sav->tdb_authalgxform = thash;

        /* Initialize crypto session. */
        memset(cria, 0, sizeof (*cria));
        cria->cri_alg = sav->tdb_authalgxform->type;
        cria->cri_klen = _KEYBITS(sav->key_auth);
        cria->cri_key = _KEYBUF(sav->key_auth);

        return 0;
}

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

        error = ah_init0(sav, xsp, &cria);
        if (!error) {
                mutex_spin_enter(&crypto_mtx);
                error = crypto_newsession(&sav->tdb_cryptoid,
                                           &cria, crypto_support);
                mutex_spin_exit(&crypto_mtx);
        }
        return error;
}

/*
 * Paranoia.
 *
 * NB: public for use by esp_zeroize (XXX).
 */
int
ah_zeroize(struct secasvar *sav)
{
        int err;

        if (sav->key_auth)
                memset(_KEYBUF(sav->key_auth), 0, _KEYLEN(sav->key_auth));

        mutex_spin_enter(&crypto_mtx);
        err = crypto_freesession(sav->tdb_cryptoid);
        mutex_spin_exit(&crypto_mtx);
        sav->tdb_cryptoid = 0;
        sav->tdb_authalgxform = NULL;
        sav->tdb_xform = NULL;
        return err;
}

/*
 * Massage IPv4/IPv6 headers for AH processing.
 */
static int
ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out)
{
        struct mbuf *m = *m0;
        unsigned char *ptr;
        int off, count;

#ifdef INET
        struct ip *ip;
#endif /* INET */

#ifdef INET6
        struct ip6_ext *ip6e;
        struct ip6_hdr ip6;
        int alloc, len, ad;
#endif /* INET6 */

        switch (proto) {
#ifdef INET
        case AF_INET:
                /*
                 * This is the least painful way of dealing with IPv4 header
                 * and option processing -- just make sure they're in
                 * contiguous memory.
                 */
                *m0 = m = m_pullup(m, skip);
                if (m == NULL) {
                        DPRINTF(("ah_massage_headers: m_pullup failed\n"));
                        return ENOBUFS;
                }

                /* Fix the IP header */
                ip = mtod(m, struct ip *);
                if (ip4_ah_cleartos)
                        ip->ip_tos = 0;
                ip->ip_ttl = 0;
                ip->ip_sum = 0;
                ip->ip_off = htons(ntohs(ip->ip_off) & ip4_ah_offsetmask);

                /*
                 * On FreeBSD, ip_off and ip_len assumed in host endian;
                 * they are converted (if necessary) by ip_input().
                 * On NetBSD, ip_off and ip_len are in network byte order.
                 * They must be massaged back to network byte order
                 * before verifying the  HMAC. Moreover, on FreeBSD,
                 * we should add `skip' back into the massaged ip_len
                 * (presumably ip_input() deducted it before we got here?)
                 * whereas on NetBSD, we should not.
                 */
#ifdef __FreeBSD__
  #define TOHOST(x) (x)
#else
  #define TOHOST(x) (ntohs(x))
#endif
                if (!out) {
                        u_int16_t inlen = TOHOST(ip->ip_len);

#ifdef __FreeBSD__
                        ip->ip_len = htons(inlen + skip);
#else  /*!__FreeBSD__ */
                        ip->ip_len = htons(inlen);
#endif /*!__FreeBSD__ */
                        DPRINTF(("ip len: skip %d, "
                                 "in %d host %d: new: raw %d host %d\n",
                                 skip,
                                 inlen, TOHOST(inlen),
                                 ip->ip_len, ntohs(ip->ip_len)));


                        if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
                                ip->ip_off  &= IP_OFF_CONVERT(IP_DF);
                        else
                                ip->ip_off = 0;
                } else {
                        if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
                                ip->ip_off &= IP_OFF_CONVERT(IP_DF);
                        else
                                ip->ip_off = 0;
                }

                ptr = mtod(m, unsigned char *) + sizeof(struct ip);

                /* IPv4 option processing */
                for (off = sizeof(struct ip); off < skip;) {
                        if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP ||
                            off + 1 < skip)
                                ;
                        else {
                                DPRINTF(("ah_massage_headers: illegal IPv4 "
                                    "option length for option %d\n",
                                    ptr[off]));

                                m_freem(m);
                                return EINVAL;
                        }

                        switch (ptr[off]) {
                        case IPOPT_EOL:
                                off = skip;  /* End the loop. */
                                break;

                        case IPOPT_NOP:
                                off++;
                                break;

                        case IPOPT_SECURITY:    /* 0x82 */
                        case 0x85:      /* Extended security. */
                        case 0x86:      /* Commercial security. */
                        case 0x94:      /* Router alert */
                        case 0x95:      /* RFC1770 */
                                /* Sanity check for option length. */
                                if (ptr[off + 1] < 2) {
                                        DPRINTF(("ah_massage_headers: "
                                            "illegal IPv4 option length for "
                                            "option %d\n", ptr[off]));

                                        m_freem(m);
                                        return EINVAL;
                                }

                                off += ptr[off + 1];
                                break;

                        case IPOPT_LSRR:
                        case IPOPT_SSRR:
                                /* Sanity check for option length. */
                                if (ptr[off + 1] < 2) {
                                        DPRINTF(("ah_massage_headers: "
                                            "illegal IPv4 option length for "
                                            "option %d\n", ptr[off]));

                                        m_freem(m);
                                        return EINVAL;
                                }

                                /*
                                 * On output, if we have either of the
                                 * source routing options, we should
                                 * swap the destination address of the
                                 * IP header with the last address
                                 * specified in the option, as that is
                                 * what the destination's IP header
                                 * will look like.
                                 */
                                if (out)
                                        bcopy(ptr + off + ptr[off + 1] -
                                            sizeof(struct in_addr),
                                            &(ip->ip_dst), sizeof(struct in_addr));

                                /* Fall through */
                        default:
                                /* Sanity check for option length. */
                                if (ptr[off + 1] < 2) {
                                        DPRINTF(("ah_massage_headers: "
                                            "illegal IPv4 option length for "
                                            "option %d\n", ptr[off]));
                                        m_freem(m);
                                        return EINVAL;
                                }

                                /* Zeroize all other options. */
                                count = ptr[off + 1];
                                memcpy(ptr, ipseczeroes, count);
                                off += count;
                                break;
                        }

                        /* Sanity check. */
                        if (off > skip) {
                                DPRINTF(("ah_massage_headers(): malformed "
                                    "IPv4 options header\n"));

                                m_freem(m);
                                return EINVAL;
                        }
                }

                break;
#endif /* INET */

#ifdef INET6
        case AF_INET6:  /* Ugly... */
                /* Copy and "cook" the IPv6 header. */
                m_copydata(m, 0, sizeof(ip6), &ip6);

                /* We don't do IPv6 Jumbograms. */
                if (ip6.ip6_plen == 0) {
                        DPRINTF(("ah_massage_headers: unsupported IPv6 jumbogram\n"));
                        m_freem(m);
                        return EMSGSIZE;
                }

                ip6.ip6_flow = 0;
                ip6.ip6_hlim = 0;
                ip6.ip6_vfc &= ~IPV6_VERSION_MASK;
                ip6.ip6_vfc |= IPV6_VERSION;

                /* Scoped address handling. */
                if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src))
                        ip6.ip6_src.s6_addr16[1] = 0;
                if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst))
                        ip6.ip6_dst.s6_addr16[1] = 0;

                /* Done with IPv6 header. */
                m_copyback(m, 0, sizeof(struct ip6_hdr), &ip6);

                /* Let's deal with the remaining headers (if any). */
                if (skip - sizeof(struct ip6_hdr) > 0) {
                        if (m->m_len <= skip) {
                                ptr = (unsigned char *) malloc(
                                    skip - sizeof(struct ip6_hdr),
                                    M_XDATA, M_NOWAIT);
                                if (ptr == NULL) {
                                        DPRINTF(("ah_massage_headers: failed "
                                            "to allocate memory for IPv6 "
                                            "headers\n"));
                                        m_freem(m);
                                        return ENOBUFS;
                                }

                                /*
                                 * Copy all the protocol headers after
                                 * the IPv6 header.
                                 */
                                m_copydata(m, sizeof(struct ip6_hdr),
                                    skip - sizeof(struct ip6_hdr), ptr);
                                alloc = 1;
                        } else {
                                /* No need to allocate memory. */
                                ptr = mtod(m, unsigned char *) +
                                    sizeof(struct ip6_hdr);
                                alloc = 0;
                        }
                } else
                        break;

                off = ip6.ip6_nxt & 0xff; /* Next header type. */

                for (len = 0; len < skip - sizeof(struct ip6_hdr);)
                        switch (off) {
                        case IPPROTO_HOPOPTS:
                        case IPPROTO_DSTOPTS:
                                ip6e = (struct ip6_ext *) (ptr + len);

                                /*
                                 * Process the mutable/immutable
                                 * options -- borrows heavily from the
                                 * KAME code.
                                 */
                                for (count = len + sizeof(struct ip6_ext);
                                     count < len + ((ip6e->ip6e_len + 1) << 3);) {
                                        if (ptr[count] == IP6OPT_PAD1) {
                                                count++;
                                                continue; /* Skip padding. */
                                        }

                                        /* Sanity check. */
                                        if (count > len +
                                            ((ip6e->ip6e_len + 1) << 3)) {
                                                m_freem(m);

                                                /* Free, if we allocated. */
                                                if (alloc)
                                                        free(ptr, M_XDATA);
                                                return EINVAL;
                                        }

                                        ad = ptr[count + 1];

                                        /* If mutable option, zeroize. */
                                        if (ptr[count] & IP6OPT_MUTABLE)
                                                memcpy(ptr + count, ipseczeroes,
                                                    ptr[count + 1]);

                                        count += ad;

                                        /* Sanity check. */
                                        if (count >
                                            skip - sizeof(struct ip6_hdr)) {
                                                m_freem(m);

                                                /* Free, if we allocated. */
                                                if (alloc)
                                                        free(ptr, M_XDATA);
                                                return EINVAL;
                                        }
                                }

                                /* Advance. */
                                len += ((ip6e->ip6e_len + 1) << 3);
                                off = ip6e->ip6e_nxt;
                                break;

                        case IPPROTO_ROUTING:
                                /*
                                 * Always include routing headers in
                                 * computation.
                                 */
                                ip6e = (struct ip6_ext *) (ptr + len);
                                len += ((ip6e->ip6e_len + 1) << 3);
                                off = ip6e->ip6e_nxt;
                                break;

                        default:
                                DPRINTF(("ah_massage_headers: unexpected "
                                    "IPv6 header type %d", off));
                                if (alloc)
                                        free(ptr, M_XDATA);
                                m_freem(m);
                                return EINVAL;
                        }

                /* Copyback and free, if we allocated. */
                if (alloc) {
                        m_copyback(m, sizeof(struct ip6_hdr),
                            skip - sizeof(struct ip6_hdr), ptr);
                        free(ptr, M_XDATA);
                }

                break;
#endif /* INET6 */
        }

        return 0;
}

/*
 * ah_input() gets called to verify that an input packet
 * passes authentication.
 */
static int
ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
{
        struct auth_hash *ahx;
        struct tdb_ident *tdbi;
        struct tdb_crypto *tc;
        struct m_tag *mtag;
        struct newah *ah;
        int hl, rplen, authsize;

        struct cryptodesc *crda;
        struct cryptop *crp;

        IPSEC_SPLASSERT_SOFTNET("ah_input");

        IPSEC_ASSERT(sav != NULL, ("ah_input: null SA"));
        IPSEC_ASSERT(sav->key_auth != NULL,
                ("ah_input: null authentication key"));
        IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
                ("ah_input: null authentication xform"));

        /* Figure out header size. */
        rplen = HDRSIZE(sav);

        /* XXX don't pullup, just copy header */
        IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen);
        if (ah == NULL) {
                DPRINTF(("ah_input: cannot pullup header\n"));
                AH_STATINC(AH_STAT_HDROPS);     /*XXX*/
                m_freem(m);
                return ENOBUFS;
        }

        /* Check replay window, if applicable. */
        if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) {
                AH_STATINC(AH_STAT_REPLAY);
                DPRINTF(("ah_input: packet replay failure: %s\n",
                          ipsec_logsastr(sav)));
                m_freem(m);
                return ENOBUFS;
        }

        /* Verify AH header length. */
        hl = ah->ah_len * sizeof (u_int32_t);
        ahx = sav->tdb_authalgxform;
        authsize = AUTHSIZE(sav);
        if (hl != authsize + rplen - sizeof (struct ah)) {
                DPRINTF(("ah_input: bad authenticator length %u (expecting %lu)"
                        " for packet in SA %s/%08lx\n",
                        hl, (u_long) (authsize + rplen - sizeof (struct ah)),
                        ipsec_address(&sav->sah->saidx.dst),
                        (u_long) ntohl(sav->spi)));
                AH_STATINC(AH_STAT_BADAUTHL);
                m_freem(m);
                return EACCES;
        }
        AH_STATADD(AH_STAT_IBYTES, m->m_pkthdr.len - skip - hl);
        DPRINTF(("ah_input skip %d poff %d\n"
                 "len: hl %d authsize %d rpl %d expect %ld\n",
                 skip, protoff,
                 hl, authsize, rplen,
                 (long)(authsize + rplen - sizeof(struct ah))));

        /* Get crypto descriptors. */
        crp = crypto_getreq(1);
        if (crp == NULL) {
                DPRINTF(("ah_input: failed to acquire crypto descriptor\n"));
                AH_STATINC(AH_STAT_CRYPTO);
                m_freem(m);
                return ENOBUFS;
        }

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

        crda->crd_skip = 0;
        crda->crd_len = m->m_pkthdr.len;
        crda->crd_inject = skip + rplen;

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

        /* 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;
        }

        /* Allocate IPsec-specific opaque crypto info. */
        if (mtag == NULL) {
                tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto) +
                        skip + rplen + authsize, M_XDATA, M_NOWAIT|M_ZERO);
        } else {
                /* Hash verification has already been done successfully. */
                tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto),
                                                    M_XDATA, M_NOWAIT|M_ZERO);
        }
        if (tc == NULL) {
                DPRINTF(("ah_input: failed to allocate tdb_crypto\n"));
                AH_STATINC(AH_STAT_CRYPTO);
                crypto_freereq(crp);
                m_freem(m);
                return ENOBUFS;
        }

        /* Only save information if crypto processing is needed. */
        if (mtag == NULL) {
                int error;

                /*
                 * Save the authenticator, the skipped portion of the packet,
                 * and the AH header.
                 */
                m_copydata(m, 0, skip + rplen + authsize, (char *)(tc+1));

                {
                        u_int8_t *pppp = ((char *)(tc+1))+skip+rplen;
                        DPRINTF(("ah_input: zeroing %d bytes of authent " \
                    "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x\n",
                                 authsize,
                                 pppp[0], pppp[1], pppp[2], pppp[3],
                                 pppp[4], pppp[5], pppp[6], pppp[7],
                                 pppp[8], pppp[9], pppp[10], pppp[11]));
                }

                /* Zeroize the authenticator on the packet. */
                m_copyback(m, skip + rplen, authsize, ipseczeroes);

                /* "Massage" the packet headers for crypto processing. */
                error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
                    skip, ahx->type, 0);
                if (error != 0) {
                        /* NB: mbuf is free'd by ah_massage_headers */
                        AH_STATINC(AH_STAT_HDROPS);
                        free(tc, M_XDATA);
                        crypto_freereq(crp);
                        return error;
                }
        }

        /* 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 = ah_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_nxt = ah->ah_nxt;
        tc->tc_protoff = protoff;
        tc->tc_skip = skip;
        tc->tc_ptr = mtag; /* Save the mtag we've identified. */

        DPRINTF(("ah: hash over %d bytes, skip %d: "
                 "crda len %d skip %d inject %d\n",
                 crp->crp_ilen, tc->tc_skip,
                 crda->crd_len, crda->crd_skip, crda->crd_inject));

        if (mtag == NULL)
                return crypto_dispatch(crp);
        else
                return ah_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

/*
 * AH input callback from the crypto driver.
 */
static int
ah_input_cb(struct cryptop *crp)
{
        int rplen, error, skip, protoff;
        unsigned char calc[AH_ALEN_MAX];
        struct mbuf *m;
        struct cryptodesc *crd;
        struct auth_hash *ahx;
        struct tdb_crypto *tc;
        struct m_tag *mtag;
        struct secasvar *sav;
        struct secasindex *saidx;
        u_int8_t nxt;
        char *ptr;
        int s, authsize;
        u_int16_t dport = 0;
        u_int16_t sport = 0;
#ifdef IPSEC_NAT_T
        struct m_tag * tag = NULL;
#endif

        crd = crp->crp_desc;

        tc = (struct tdb_crypto *) crp->crp_opaque;
        IPSEC_ASSERT(tc != NULL, ("ah_input_cb: null opaque crypto data area!"));
        skip = tc->tc_skip;
        nxt = tc->tc_nxt;
        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) {
                AH_STATINC(AH_STAT_NOTDB);
                DPRINTF(("ah_input_cb: SA expired while in crypto\n"));
                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));

        ahx = (struct auth_hash *) sav->tdb_authalgxform;

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

                if (crp->crp_etype == EAGAIN)
                        return crypto_dispatch(crp);

                AH_STATINC(AH_STAT_NOXFORM);
                DPRINTF(("ah_input_cb: crypto error %d\n", crp->crp_etype));
                error = crp->crp_etype;
                goto bad;
        } else {
                AH_STATINC(AH_STAT_HIST + sav->alg_auth);
                crypto_freereq(crp);            /* No longer needed. */
                crp = NULL;
        }

        /* Shouldn't happen... */
        if (m == NULL) {
                AH_STATINC(AH_STAT_CRYPTO);
                DPRINTF(("ah_input_cb: bogus returned buffer from crypto\n"));
                error = EINVAL;
                goto bad;
        }

        /* Figure out header size. */
        rplen = HDRSIZE(sav);
        authsize = AUTHSIZE(sav);

        if (ipsec_debug)
          memset(calc, 0, sizeof(calc));

        /* Copy authenticator off the packet. */
        m_copydata(m, skip + rplen, authsize, calc);

        /*
         * If we have an mtag, we don't need to verify the authenticator --
         * it has been verified by an IPsec-aware NIC.
         */
        if (mtag == NULL) {
                ptr = (char *) (tc + 1);

                /* Verify authenticator. */
                if (memcmp(ptr + skip + rplen, calc, authsize)) {
                        u_int8_t *pppp = ptr + skip+rplen;
                        DPRINTF(("ah_input: authentication hash mismatch " \
                            "over %d bytes " \
                            "for packet in SA %s/%08lx:\n" \
                    "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x, " \
                    "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x\n",
                            authsize,
                            ipsec_address(&saidx->dst),
                            (u_long) ntohl(sav->spi),
                                 calc[0], calc[1], calc[2], calc[3],
                                 calc[4], calc[5], calc[6], calc[7],
                                 calc[8], calc[9], calc[10], calc[11],
                                 pppp[0], pppp[1], pppp[2], pppp[3],
                                 pppp[4], pppp[5], pppp[6], pppp[7],
                                 pppp[8], pppp[9], pppp[10], pppp[11]
                                 ));
                        AH_STATINC(AH_STAT_BADAUTH);
                        error = EACCES;
                        goto bad;
                }

                /* Fix the Next Protocol field. */
                ((u_int8_t *) ptr)[protoff] = nxt;

                /* Copyback the saved (uncooked) network headers. */
                m_copyback(m, 0, skip, ptr);
        } else {
                /* Fix the Next Protocol field. */
                m_copyback(m, protoff, sizeof(u_int8_t), &nxt);
        }

        free(tc, M_XDATA), tc = NULL;                   /* No longer needed */

        /*
         * Header is now authenticated.
         */
        m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM;

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

                m_copydata(m, skip + offsetof(struct newah, ah_seq),
                           sizeof (seq), &seq);
                if (ipsec_updatereplay(ntohl(seq), sav)) {
                        AH_STATINC(AH_STAT_REPLAY);
                        error = ENOBUFS;                        /*XXX as above*/
                        goto bad;
                }
        }

        /*
         * Remove the AH header and authenticator from the mbuf.
         */
        error = m_striphdr(m, skip, rplen + authsize);
        if (error) {
                DPRINTF(("ah_input_cb: mangled mbuf chain for SA %s/%08lx\n",
                    ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));

                AH_STATINC(AH_STAT_HDROPS);
                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;
}

/*
 * AH output routine, called by ipsec[46]_process_packet().
 */
static int
ah_output(
    struct mbuf *m,
    struct ipsecrequest *isr,
    struct mbuf **mp,
    int skip,
    int protoff
)
{
        struct secasvar *sav;
        struct auth_hash *ahx;
        struct cryptodesc *crda;
        struct tdb_crypto *tc;
        struct mbuf *mi;
        struct cryptop *crp;
        u_int16_t iplen;
        int error, rplen, authsize, maxpacketsize, roff;
        u_int8_t prot;
        struct newah *ah;

        IPSEC_SPLASSERT_SOFTNET("ah_output");

        sav = isr->sav;
        IPSEC_ASSERT(sav != NULL, ("ah_output: null SA"));
        ahx = sav->tdb_authalgxform;
        IPSEC_ASSERT(ahx != NULL, ("ah_output: null authentication xform"));

        AH_STATINC(AH_STAT_OUTPUT);

        /* Figure out header size. */
        rplen = HDRSIZE(sav);

        /* Check for maximum packet size violations. */
        switch (sav->sah->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(("ah_output: unknown/unsupported protocol "
                    "family %u, SA %s/%08lx\n",
                    sav->sah->saidx.dst.sa.sa_family,
                    ipsec_address(&sav->sah->saidx.dst),
                    (u_long) ntohl(sav->spi)));
                AH_STATINC(AH_STAT_NOPF);
                error = EPFNOSUPPORT;
                goto bad;
        }
        authsize = AUTHSIZE(sav);
        if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) {
                DPRINTF(("ah_output: packet in SA %s/%08lx got too big "
                    "(len %u, max len %u)\n",
                    ipsec_address(&sav->sah->saidx.dst),
                    (u_long) ntohl(sav->spi),
                    rplen + authsize + m->m_pkthdr.len, maxpacketsize));
                AH_STATINC(AH_STAT_TOOBIG);
                error = EMSGSIZE;
                goto bad;
        }

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

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

        /* Inject AH header. */
        mi = m_makespace(m, skip, rplen + authsize, &roff);
        if (mi == NULL) {
                DPRINTF(("ah_output: failed to inject %u byte AH header for SA "
                    "%s/%08lx\n",
                    rplen + authsize,
                    ipsec_address(&sav->sah->saidx.dst),
                    (u_long) ntohl(sav->spi)));
                AH_STATINC(AH_STAT_HDROPS);     /*XXX differs from openbsd */
                error = ENOBUFS;
                goto bad;
        }

        /*
         * The AH header is guaranteed by m_makespace() to be in
         * contiguous memory, at roff bytes offset into the returned mbuf.
         */
        ah = (struct newah *)(mtod(mi, char *) + roff);

        /* Initialize the AH header. */
        m_copydata(m, protoff, sizeof(u_int8_t), (char *) &ah->ah_nxt);
        ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t);
        ah->ah_reserve = 0;
        ah->ah_spi = sav->spi;

        /* Zeroize authenticator. */
        m_copyback(m, skip + rplen, authsize, ipseczeroes);

        /* Insert packet replay counter, as requested.  */
        if (sav->replay) {
                if (sav->replay->count == ~0 &&
                    (sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
                        DPRINTF(("ah_output: replay counter wrapped for SA "
                                "%s/%08lx\n",
                                ipsec_address(&sav->sah->saidx.dst),
                                (u_long) ntohl(sav->spi)));
                        AH_STATINC(AH_STAT_WRAP);
                        error = EINVAL;
                        goto bad;
                }
#ifdef IPSEC_DEBUG
                /* Emulate replay attack when ipsec_replay is TRUE. */
                if (!ipsec_replay)
#endif
                        sav->replay->count++;
                ah->ah_seq = htonl(sav->replay->count);
        }

        /* Get crypto descriptors. */
        crp = crypto_getreq(1);
        if (crp == NULL) {
                DPRINTF(("ah_output: failed to acquire crypto descriptors\n"));
                AH_STATINC(AH_STAT_CRYPTO);
                error = ENOBUFS;
                goto bad;
        }

        crda = crp->crp_desc;

        crda->crd_skip = 0;
        crda->crd_inject = skip + rplen;
        crda->crd_len = m->m_pkthdr.len;

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

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

        /* Save the skipped portion of the packet. */
        m_copydata(m, 0, skip, (tc + 1));

        /*
         * Fix IP header length on the header used for
         * authentication. We don't need to fix the original
         * header length as it will be fixed by our caller.
         */
        switch (sav->sah->saidx.dst.sa.sa_family) {
#ifdef INET
        case AF_INET:
                bcopy(((char *)(tc + 1)) +
                    offsetof(struct ip, ip_len),
                    &iplen, sizeof(u_int16_t));
                iplen = htons(ntohs(iplen) + rplen + authsize);
                m_copyback(m, offsetof(struct ip, ip_len),
                    sizeof(u_int16_t), &iplen);
                break;
#endif /* INET */

#ifdef INET6
        case AF_INET6:
                bcopy(((char *)(tc + 1)) +
                    offsetof(struct ip6_hdr, ip6_plen),
                    &iplen, sizeof(u_int16_t));
                iplen = htons(ntohs(iplen) + rplen + authsize);
                m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
                    sizeof(u_int16_t), &iplen);
                break;
#endif /* INET6 */
        }

        /* Fix the Next Header field in saved header. */
        ((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH;

        /* Update the Next Protocol field in the IP header. */
        prot = IPPROTO_AH;
        m_copyback(m, protoff, sizeof(u_int8_t), &prot);

        /* "Massage" the packet headers for crypto processing. */
        error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
                        skip, ahx->type, 1);
        if (error != 0) {
                m = NULL;       /* mbuf was free'd by ah_massage_headers. */
                free(tc, M_XDATA);
                crypto_freereq(crp);
                goto bad;
        }

        /* 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 = ah_output_cb;
        crp->crp_sid = sav->tdb_cryptoid;
        crp->crp_opaque = tc;

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

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

/*
 * AH output callback from the crypto driver.
 */
static int
ah_output_cb(struct cryptop *crp)
{
        int skip, protoff, error;
        struct tdb_crypto *tc;
        struct ipsecrequest *isr;
        struct secasvar *sav;
        struct mbuf *m;
        void *ptr;
        int s, err;

        tc = (struct tdb_crypto *) crp->crp_opaque;
        IPSEC_ASSERT(tc != NULL, ("ah_output_cb: null opaque data area!"));
        skip = tc->tc_skip;
        protoff = tc->tc_protoff;
        ptr = (tc + 1);
        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) {
                AH_STATINC(AH_STAT_NOTDB);
                DPRINTF(("ah_output_cb: SA expired while in crypto\n"));
                error = ENOBUFS;                /*XXX*/
                goto bad;
        }
        IPSEC_ASSERT(isr->sav == sav, ("ah_output_cb: SA changed\n"));

        /* Check for crypto errors. */
        if (crp->crp_etype) {
                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);
                }

                AH_STATINC(AH_STAT_NOXFORM);
                DPRINTF(("ah_output_cb: crypto error %d\n", crp->crp_etype));
                error = crp->crp_etype;
                goto bad;
        }

        /* Shouldn't happen... */
        if (m == NULL) {
                AH_STATINC(AH_STAT_CRYPTO);
                DPRINTF(("ah_output_cb: bogus returned buffer from crypto\n"));
                error = EINVAL;
                goto bad;
        }
        AH_STATINC(AH_STAT_HIST + sav->alg_auth);

        /*
         * Copy original headers (with the new protocol number) back
         * in place.
         */
        m_copyback(m, 0, skip, ptr);

        /* No longer needed. */
        free(tc, M_XDATA);
        crypto_freereq(crp);

#ifdef IPSEC_DEBUG
        /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
        if (ipsec_integrity) {
                int alen;

                /*
                 * Corrupt HMAC if we want to test integrity verification of
                 * the other side.
                 */
                alen = AUTHSIZE(sav);
                m_copyback(m, m->m_pkthdr.len - alen, alen, 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 ah_xformsw = {
        XF_AH,          XFT_AUTH,       "IPsec AH",
        ah_init,        ah_zeroize,     ah_input,       ah_output,
        NULL,
};

INITFN void
ah_attach(void)
{
        ahstat_percpu = percpu_alloc(sizeof(uint64_t) * AH_NSTATS);
        xform_register(&ah_xformsw);
}

#ifdef __FreeBSD__
SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL);
#endif