"Fast IPsec": this is an experimental IPsec implementation that is derived

from the KAME IPsec implementation, but with heavy borrowing and influence
of openbsd.  A key feature of this implementation is that it uses the kernel
crypto framework to do all crypto work so when h/w crypto support is present
IPsec operation is automatically accelerated.  Otherwise the protocol
implementations are rather differet while the SADB and policy management
code is very similar to KAME (for the moment).

Note that this implementation is enabled with a FAST_IPSEC option.  With this
you get all protocols; i.e. there is no FAST_IPSEC_ESP option.

FAST_IPSEC and IPSEC are mutually exclusive; you cannot build both into a
single system.

This software is well tested with IPv4 but should be considered very
experimental (i.e. do not deploy in production environments).  This software
does NOT currently support IPv6.  In fact do not configure FAST_IPSEC and
INET6 in the same system.

Obtained from:	KAME + openbsd
Supported by:	Vernier Networks

1 files changed, 966 insertions, 0 deletions

diff --git a/sys/netipsec/xform_esp.c b/sys/netipsec/xform_esp.c
new file mode 100644
index 0000000..f91d3cf
--- /dev/null
+++ b/sys/netipsec/xform_esp.c
@@ -0,0 +1,966 @@
+/*	$FreeBSD$	*/
+/*	$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 "opt_inet.h"
+#include "opt_inet6.h"
+
+#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/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>
+#include <netinet6/ip6_ecn.h>
+#endif
+
+#include <netipsec/key.h>
+#include <netipsec/key_debug.h>
+
+#include <opencrypto/cryptodev.h>
+#include <opencrypto/xform.h>
+
+int	esp_enable = 1;
+struct	espstat espstat;
+
+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, "");
+
+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??*/
+		KASSERT(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 = (caddr_t) malloc(sav->ivlen, M_XDATA, 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. */
+	bzero(&crie, 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 ? */
+
+	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;
+	}
+	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)
+		bzero(_KEYBUF(sav->key_enc), _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;
+
+#if 0
+	SPLASSERT(net, "esp_input");
+#endif
+
+	KASSERT(sav != NULL, ("esp_input: null SA"));
+	KASSERT(sav->tdb_encalgxform != NULL,
+		("esp_input: null encoding xform"));
+	KASSERT((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)));
+		espstat.esps_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*/
+		espstat.esps_replay++;
+		m_freem(m);
+		return ENOBUFS;		/*XXX*/
+	}
+
+	/* Update the counters */
+	espstat.esps_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 &&
+		    !bcmp(&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"));
+		espstat.esps_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"));
+		espstat.esps_crypto++;
+		m_freem(m);
+		return ENOBUFS;
+	}
+
+	tc->tc_ptr = (caddr_t) mtag;
+
+	if (esph) {
+		struct cryptodesc *crda = crp->crp_desc;
+
+		KASSERT(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,
+				   (caddr_t) (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 | CRYPTO_F_NODELAY;
+	crp->crp_buf = (caddr_t) m;
+	crp->crp_callback = esp_input_cb;
+	crp->crp_sid = sav->tdb_cryptoid;
+	crp->crp_opaque = (caddr_t) 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) {
+		KASSERT(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;
+	caddr_t ptr;
+
+	crd = crp->crp_desc;
+	KASSERT(crd != NULL, ("esp_input_cb: null crypto descriptor!"));
+
+	tc = (struct tdb_crypto *) crp->crp_opaque;
+	KASSERT(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;
+
+	s = splnet();
+
+	sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
+	if (sav == NULL) {
+		espstat.esps_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;
+	KASSERT(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);
+		}
+
+		espstat.esps_noxform++;
+		DPRINTF(("esp_input_cb: crypto error %d\n", crp->crp_etype));
+		error = crp->crp_etype;
+		goto bad;
+	}
+
+	/* Shouldn't happen... */
+	if (m == NULL) {
+		espstat.esps_crypto++;
+		DPRINTF(("esp_input_cb: bogus returned buffer from crypto\n"));
+		error = EINVAL;
+		goto bad;
+	}
+	espstat.esps_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.
+		 */
+		ahstat.ahs_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 = (caddr_t) (tc + 1);
+
+			/* Verify authenticator */
+			if (bcmp(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)));
+				espstat.esps_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;
+
+	/* 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) {
+		espstat.esps_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) {
+		espstat.esps_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) {
+			espstat.esps_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_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
+
+	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;
+
+#if 0
+	SPLASSERT(net, "esp_output");
+#endif
+
+	sav = isr->sav;
+	KASSERT(sav != NULL, ("esp_output: null SA"));
+	esph = sav->tdb_authalgxform;
+	espx = sav->tdb_encalgxform;
+	KASSERT(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;
+
+	espstat.esps_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)));
+		espstat.esps_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));
+		espstat.esps_toobig++;
+		error = EMSGSIZE;
+		goto bad;
+	}
+
+	/* Update the counters. */
+	espstat.esps_obytes += 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)));
+		espstat.esps_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)));
+		espstat.esps_hdrops++;		/* XXX diffs from openbsd */
+		error = ENOBUFS;
+		goto bad;
+	}
+
+	/* Initialize ESP header. */
+	bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t));
+	if (sav->replay) {
+		u_int32_t replay = htonl(++(sav->replay->count));
+		bcopy((caddr_t) &replay,
+		    mtod(mo, caddr_t) + 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:
+		bzero(pad, 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"));
+		espstat.esps_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"));
+		espstat.esps_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 = (caddr_t) m;
+	crp->crp_callback = esp_output_cb;
+	crp->crp_opaque = (caddr_t) 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;
+	KASSERT(tc != NULL, ("esp_output_cb: null opaque data area!"));
+	m = (struct mbuf *) crp->crp_buf;
+
+	s = splnet();
+
+	isr = tc->tc_isr;
+	sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
+	if (sav == NULL) {
+		espstat.esps_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;
+	}
+	KASSERT(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);
+		}
+
+		espstat.esps_noxform++;
+		DPRINTF(("esp_output_cb: crypto error %d\n", crp->crp_etype));
+		error = crp->crp_etype;
+		goto bad;
+	}
+
+	/* Shouldn't happen... */
+	if (m == NULL) {
+		espstat.esps_crypto++;
+		DPRINTF(("esp_output_cb: bogus returned buffer from crypto\n"));
+		error = EINVAL;
+		goto bad;
+	}
+	espstat.esps_hist[sav->alg_enc]++;
+	if (sav->tdb_authalgxform != NULL)
+		ahstat.ahs_hist[sav->alg_auth]++;
+
+	/* Release crypto descriptors. */
+	free(tc, M_XDATA);
+	crypto_freereq(crp);
+
+	/* 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
+};
+
+static void
+esp_attach(void)
+{
+#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
+}
+SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL)