"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, 1209 insertions, 0 deletions

diff --git a/sys/netipsec/xform_ah.c b/sys/netipsec/xform_ah.c
new file mode 100644
index 0000000..1063aad
--- /dev/null
+++ b/sys/netipsec/xform_ah.c
@@ -0,0 +1,1209 @@
+/*	$FreeBSD$	*/
+/*	$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 "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/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/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>
+
+/*
+ * 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)
+
+int	ah_enable = 1;			/* control flow of packets with AH */
+int	ah_cleartos = 1;		/* clear ip_tos when doing AH calc */
+struct	ahstat ahstat;
+
+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,	&ah_cleartos,	0, "");
+SYSCTL_STRUCT(_net_inet_ah, IPSECCTL_STATS,
+	stats,		CTLFLAG_RD,	&ahstat,	ahstat, "");
+
+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;
+		KASSERT(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. */
+	bzero(cria, 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);
+	return error ? error :
+		 crypto_newsession(&sav->tdb_cryptoid, &cria, crypto_support);
+}
+
+/*
+ * Paranoia.
+ *
+ * NB: public for use by esp_zeroize (XXX).
+ */
+int
+ah_zeroize(struct secasvar *sav)
+{
+	int err;
+
+	if (sav->key_auth)
+		bzero(_KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth));
+
+	err = crypto_freesession(sav->tdb_cryptoid);
+	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 (ah_cleartos)
+			ip->ip_tos = 0;
+		ip->ip_ttl = 0;
+		ip->ip_sum = 0;
+
+		/*
+		 * On input, fix ip_len which has been byte-swapped
+		 * at ip_input().
+		 */
+		if (!out) {
+			ip->ip_len = htons(ip->ip_len + skip);
+
+			if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
+				ip->ip_off = htons(ip->ip_off & IP_DF);
+			else
+				ip->ip_off = 0;
+		} else {
+			if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
+				ip->ip_off = htons(ntohs(ip->ip_off) & 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];
+				bcopy(ipseczeroes, ptr, 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), (caddr_t) &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), (caddr_t) &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)
+						bcopy(ipseczeroes, ptr + count,
+						    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;
+
+#if 0
+	SPLASSERT(net, "ah_input");
+#endif
+
+	KASSERT(sav != NULL, ("ah_input: null SA"));
+	KASSERT(sav->key_auth != NULL,
+		("ah_input: null authentication key"));
+	KASSERT(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"));
+		ahstat.ahs_hdrops++;		/*XXX*/
+		m_freem(m);
+		return ENOBUFS;
+	}
+
+	/* Check replay window, if applicable. */
+	if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) {
+		ahstat.ahs_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)));
+		ahstat.ahs_badauthl++;
+		m_freem(m);
+		return EACCES;
+	}
+	ahstat.ahs_ibytes += m->m_pkthdr.len - skip - hl;
+
+	/* Get crypto descriptors. */
+	crp = crypto_getreq(1);
+	if (crp == NULL) {
+		DPRINTF(("ah_input: failed to acquire crypto descriptor\n"));
+		ahstat.ahs_crypto++;
+		m_freem(m);
+		return ENOBUFS;
+	}
+
+	crda = crp->crp_desc;
+	KASSERT(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 &&
+		    !bcmp(&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"));
+		ahstat.ahs_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, (caddr_t)(tc+1));
+
+		/* 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 */
+			ahstat.ahs_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 | CRYPTO_F_NODELAY;
+	crp->crp_buf = (caddr_t) m;
+	crp->crp_callback = ah_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_nxt = ah->ah_nxt;
+	tc->tc_protoff = protoff;
+	tc->tc_skip = skip;
+	tc->tc_ptr = (caddr_t) mtag; /* Save the mtag we've identified. */
+
+	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;
+	caddr_t ptr;
+	int s, authsize;
+
+	crd = crp->crp_desc;
+
+	tc = (struct tdb_crypto *) crp->crp_opaque;
+	KASSERT(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;
+
+	s = splnet();
+
+	sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
+	if (sav == NULL) {
+		ahstat.ahs_notdb++;
+		DPRINTF(("ah_input_cb: SA expired while in crypto\n"));
+		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));
+
+	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);
+
+		ahstat.ahs_noxform++;
+		DPRINTF(("ah_input_cb: crypto error %d\n", crp->crp_etype));
+		error = crp->crp_etype;
+		goto bad;
+	} else {
+		ahstat.ahs_hist[sav->alg_auth]++;
+		crypto_freereq(crp);		/* No longer needed. */
+		crp = NULL;
+	}
+
+	/* Shouldn't happen... */
+	if (m == NULL) {
+		ahstat.ahs_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);
+
+	/* 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 = (caddr_t) (tc + 1);
+
+		/* Verify authenticator. */
+		if (bcmp(ptr + skip + rplen, calc, authsize)) {
+			DPRINTF(("ah_input: authentication hash mismatch "
+			    "for packet in SA %s/%08lx\n",
+			    ipsec_address(&saidx->dst),
+			    (u_long) ntohl(sav->spi)));
+			ahstat.ahs_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), (caddr_t) &seq);
+		if (ipsec_updatereplay(ntohl(seq), sav)) {
+			ahstat.ahs_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)));
+
+		ahstat.ahs_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;
+
+#if 0
+	SPLASSERT(net, "ah_output");
+#endif
+
+	sav = isr->sav;
+	KASSERT(sav != NULL, ("ah_output: null SA"));
+	ahx = sav->tdb_authalgxform;
+	KASSERT(ahx != NULL, ("ah_output: null authentication xform"));
+
+	ahstat.ahs_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)));
+		ahstat.ahs_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));
+		ahstat.ahs_toobig++;
+		error = EMSGSIZE;
+		goto bad;
+	}
+
+	/* Update the counters. */
+	ahstat.ahs_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)));
+		ahstat.ahs_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)));
+		ahstat.ahs_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, caddr_t) + roff);
+
+	/* Initialize the AH header. */
+	m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &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)));
+			ahstat.ahs_wrap++;
+			error = EINVAL;
+			goto bad;
+		}
+		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"));
+		ahstat.ahs_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"));
+		ahstat.ahs_crypto++;
+		error = ENOBUFS;
+		goto bad;
+	}
+
+	/* Save the skipped portion of the packet. */
+	m_copydata(m, 0, skip, (caddr_t) (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(((caddr_t)(tc + 1)) +
+		    offsetof(struct ip, ip_len),
+		    (caddr_t) &iplen, sizeof(u_int16_t));
+		iplen = htons(ntohs(iplen) + rplen + authsize);
+		m_copyback(m, offsetof(struct ip, ip_len),
+		    sizeof(u_int16_t), (caddr_t) &iplen);
+		break;
+#endif /* INET */
+
+#ifdef INET6
+	case AF_INET6:
+		bcopy(((caddr_t)(tc + 1)) +
+		    offsetof(struct ip6_hdr, ip6_plen),
+		    (caddr_t) &iplen, sizeof(u_int16_t));
+		iplen = htons(ntohs(iplen) + rplen + authsize);
+		m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
+		    sizeof(u_int16_t), (caddr_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), (caddr_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 = (caddr_t) m;
+	crp->crp_callback = ah_output_cb;
+	crp->crp_sid = sav->tdb_cryptoid;
+	crp->crp_opaque = (caddr_t) 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;
+	caddr_t ptr;
+	int s, err;
+
+	tc = (struct tdb_crypto *) crp->crp_opaque;
+	KASSERT(tc != NULL, ("ah_output_cb: null opaque data area!"));
+	skip = tc->tc_skip;
+	protoff = tc->tc_protoff;
+	ptr = (caddr_t) (tc + 1);
+	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) {
+		ahstat.ahs_notdb++;
+		DPRINTF(("ah_output_cb: SA expired while in crypto\n"));
+		error = ENOBUFS;		/*XXX*/
+		goto bad;
+	}
+	KASSERT(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);
+		}
+
+		ahstat.ahs_noxform++;
+		DPRINTF(("ah_output_cb: crypto error %d\n", crp->crp_etype));
+		error = crp->crp_etype;
+		goto bad;
+	}
+
+	/* Shouldn't happen... */
+	if (m == NULL) {
+		ahstat.ahs_crypto++;
+		DPRINTF(("ah_output_cb: bogus returned buffer from crypto\n"));
+		error = EINVAL;
+		goto bad;
+	}
+	ahstat.ahs_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);
+
+	/* 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,
+};
+
+static void
+ah_attach(void)
+{
+	xform_register(&ah_xformsw);
+}
+SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL);