/* $OpenBSD: ip_ipcomp.c,v 1.1 2001/07/05 12:08:52 jjbg Exp $ */

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2001 Jean-Jacques Bernard-Gundol (jj@wabbitt.org)
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/* IP payload compression protocol (IPComp), see RFC 2393 */
#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_ipsec.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/socket.h>
#include <sys/kernel.h>
#include <sys/protosw.h>
#include <sys/sysctl.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/ip_encap.h>

#include <net/netisr.h>
#include <net/vnet.h>
#include <net/if.h>     /* XXXGL: net_epoch should move out there */
#include <net/if_var.h> /* XXXGL: net_epoch should move out there */

#include <netipsec/ipsec.h>
#include <netipsec/xform.h>

#ifdef INET6
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netipsec/ipsec6.h>
#endif

#include <netipsec/ipcomp.h>
#include <netipsec/ipcomp_var.h>

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

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

VNET_DEFINE(int, ipcomp_enable) = 1;
VNET_PCPUSTAT_DEFINE(struct ipcompstat, ipcompstat);
VNET_PCPUSTAT_SYSINIT(ipcompstat);

#ifdef VIMAGE
VNET_PCPUSTAT_SYSUNINIT(ipcompstat);
#endif /* VIMAGE */

SYSCTL_DECL(_net_inet_ipcomp);
SYSCTL_INT(_net_inet_ipcomp, OID_AUTO, ipcomp_enable,
        CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ipcomp_enable), 0, "");
SYSCTL_VNET_PCPUSTAT(_net_inet_ipcomp, IPSECCTL_STATS, stats,
    struct ipcompstat, ipcompstat,
    "IPCOMP statistics (struct ipcompstat, netipsec/ipcomp_var.h");

static MALLOC_DEFINE(M_IPCOMP, "ipcomp", "IPCOMP");

static int ipcomp_input_cb(struct cryptop *crp);
static int ipcomp_output_cb(struct cryptop *crp);

/*
 * RFC 3173 p 2.2. Non-Expansion Policy:
 * If the total size of a compressed payload and the IPComp header, as
 * defined in section 3, is not smaller than the size of the original
 * payload, the IP datagram MUST be sent in the original non-compressed
 * form.
 *
 * When we use IPComp in tunnel mode, for small packets we will receive
 * encapsulated IP-IP datagrams without any compression and without IPComp
 * header.
 */
static int
ipcomp_encapcheck(union sockaddr_union *src, union sockaddr_union *dst)
{
        struct secasvar *sav;

        sav = key_allocsa_tunnel(src, dst, IPPROTO_IPCOMP);
        if (sav == NULL)
                return (0);
        key_freesav(&sav);

        if (src->sa.sa_family == AF_INET)
                return (sizeof(struct in_addr) << 4);
        else
                return (sizeof(struct in6_addr) << 4);
}

static int
ipcomp_nonexp_input(struct mbuf *m, int off, int proto, void *arg __unused)
{
        int isr;

        NET_EPOCH_ASSERT();

        switch (proto) {
#ifdef INET
        case IPPROTO_IPV4:
                isr = NETISR_IP;
                break;
#endif
#ifdef INET6
        case IPPROTO_IPV6:
                isr = NETISR_IPV6;
                break;
#endif
        default:
                IPCOMPSTAT_INC(ipcomps_nopf);
                m_freem(m);
                return (IPPROTO_DONE);
        }
        m_adj(m, off);
        IPCOMPSTAT_ADD(ipcomps_ibytes, m->m_pkthdr.len);
        IPCOMPSTAT_INC(ipcomps_input);
        netisr_dispatch(isr, m);
        return (IPPROTO_DONE);
}

/*
 * ipcomp_init() is called when an CPI is being set up.
 */
static int
ipcomp_init(struct secasvar *sav, struct xformsw *xsp)
{
        const struct comp_algo *tcomp;
        struct crypto_session_params csp;

        /* NB: algorithm really comes in alg_enc and not alg_comp! */
        tcomp = comp_algorithm_lookup(sav->alg_enc);
        if (tcomp == NULL) {
                DPRINTF(("%s: unsupported compression algorithm %d\n", __func__,
                         sav->alg_comp));
                return EINVAL;
        }
        sav->alg_comp = sav->alg_enc;           /* set for doing histogram */
        sav->tdb_xform = xsp;
        sav->tdb_compalgxform = tcomp;

        /* Initialize crypto session */
        memset(&csp, 0, sizeof(csp));
        csp.csp_mode = CSP_MODE_COMPRESS;
        csp.csp_cipher_alg = sav->tdb_compalgxform->type;

        return crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support);
}

/*
 * ipcomp_cleanup() used when IPCA is deleted
 */
static void
ipcomp_cleanup(struct secasvar *sav)
{

        crypto_freesession(sav->tdb_cryptoid);
        sav->tdb_cryptoid = NULL;
}

/*
 * ipcomp_input() gets called to uncompress an input packet
 */
static int
ipcomp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
{
        struct xform_data *xd;
        struct cryptop *crp;
        struct ipcomp *ipcomp;
        crypto_session_t cryptoid;
        caddr_t addr;
        int error, hlen = IPCOMP_HLENGTH;

        SECASVAR_RLOCK_TRACKER;

        /*
         * Check that the next header of the IPComp is not IPComp again, before
         * doing any real work.  Given it is not possible to do double
         * compression it means someone is playing tricks on us.
         */
        error = ENOBUFS;
        if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
                IPCOMPSTAT_INC(ipcomps_hdrops);         /*XXX*/
                DPRINTF(("%s: m_pullup failed\n", __func__));
                key_freesav(&sav);
                return (error);
        }
        addr = (caddr_t) mtod(m, struct ip *) + skip;
        ipcomp = (struct ipcomp *)addr;
        if (ipcomp->comp_nxt == IPPROTO_IPCOMP) {
                IPCOMPSTAT_INC(ipcomps_pdrops); /* XXX have our own stats? */
                DPRINTF(("%s: recursive compression detected\n", __func__));
                error = EINVAL;
                goto bad;
        }

        SECASVAR_RLOCK(sav);
        cryptoid = sav->tdb_cryptoid;
        SECASVAR_RUNLOCK(sav);

        /* Get crypto descriptors */
        crp = crypto_getreq(cryptoid, M_NOWAIT);
        if (crp == NULL) {
                DPRINTF(("%s: no crypto descriptors\n", __func__));
                IPCOMPSTAT_INC(ipcomps_crypto);
                goto bad;
        }
        /* Get IPsec-specific opaque pointer */
        xd = malloc(sizeof(*xd), M_IPCOMP, M_NOWAIT | M_ZERO);
        if (xd == NULL) {
                DPRINTF(("%s: cannot allocate xform_data\n", __func__));
                IPCOMPSTAT_INC(ipcomps_crypto);
                crypto_freereq(crp);
                goto bad;
        }

        /* Decompression operation */
        crp->crp_op = CRYPTO_OP_DECOMPRESS;
        crp->crp_payload_start = skip + hlen;
        crp->crp_payload_length = m->m_pkthdr.len - (skip + hlen);

        /* Crypto operation descriptor */
        crp->crp_flags = CRYPTO_F_CBIFSYNC;
        crypto_use_mbuf(crp, m);
        crp->crp_callback = ipcomp_input_cb;
        crp->crp_opaque = xd;

        /* These are passed as-is to the callback */
        xd->sav = sav;
        xd->protoff = protoff;
        xd->skip = skip;
        xd->vnet = curvnet;
        xd->cryptoid = cryptoid;

        SECASVAR_RLOCK(sav);
        crp->crp_session = xd->cryptoid = sav->tdb_cryptoid;
        SECASVAR_RUNLOCK(sav);

        return crypto_dispatch(crp);
bad:
        m_freem(m);
        key_freesav(&sav);
        return (error);
}

/*
 * IPComp input callback from the crypto driver.
 */
static int
ipcomp_input_cb(struct cryptop *crp)
{
        IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
        struct rm_priotracker sahtree_tracker;
        struct xform_data *xd;
        struct mbuf *m;
        struct secasvar *sav;
        struct secasindex *saidx;
        caddr_t addr;
        crypto_session_t cryptoid;
        int hlen = IPCOMP_HLENGTH, error, clen;
        int skip, protoff;
        uint8_t nproto;

        m = crp->crp_buf.cb_mbuf;
        xd = crp->crp_opaque;
        CURVNET_SET(xd->vnet);
        sav = xd->sav;
        skip = xd->skip;
        protoff = xd->protoff;
        cryptoid = xd->cryptoid;
        ipsec_sahtree_rlock(&sahtree_tracker);
        if (sav->state >= SADB_SASTATE_DEAD) {
                /* saidx is freed */
                DPRINTF(("%s: dead SA %p spi %#x\n", __func__, sav, sav->spi));
                IPCOMPSTAT_INC(ipcomps_notdb);
                error = ESRCH;
                goto bad;
        }
        saidx = &sav->sah->saidx;
        IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
                saidx->dst.sa.sa_family == AF_INET6,
                ("unexpected protocol family %u", saidx->dst.sa.sa_family));

        /* Check for crypto errors */
        if (crp->crp_etype) {
                if (crp->crp_etype == EAGAIN) {
                        /* Reset the session ID */
                        if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
                                crypto_freesession(cryptoid);
                        xd->cryptoid = crp->crp_session;
                        CURVNET_RESTORE();
                        return (crypto_dispatch(crp));
                }
                IPCOMPSTAT_INC(ipcomps_noxform);
                DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
                error = crp->crp_etype;
                goto bad;
        }
        /* Shouldn't happen... */
        if (m == NULL) {
                IPCOMPSTAT_INC(ipcomps_crypto);
                DPRINTF(("%s: null mbuf returned from crypto\n", __func__));
                error = EINVAL;
                goto bad;
        }
        IPCOMPSTAT_INC2(ipcomps_hist, sav->alg_comp);

        clen = crp->crp_olen;           /* Length of data after processing */

        /* Release the crypto descriptors */
        free(xd, M_IPCOMP), xd = NULL;
        crypto_freereq(crp), crp = NULL;

        /* In case it's not done already, adjust the size of the mbuf chain */
        m->m_pkthdr.len = clen + hlen + skip;

        if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
                IPCOMPSTAT_INC(ipcomps_hdrops);         /*XXX*/
                DPRINTF(("%s: m_pullup failed\n", __func__));
                error = EINVAL;                         /*XXX*/
                goto bad;
        }

        /* Keep the next protocol field */
        addr = (caddr_t) mtod(m, struct ip *) + skip;
        nproto = ((struct ipcomp *) addr)->comp_nxt;

        /* Remove the IPCOMP header */
        error = m_striphdr(m, skip, hlen);
        if (error) {
                IPCOMPSTAT_INC(ipcomps_hdrops);
                DPRINTF(("%s: bad mbuf chain, IPCA %s/%08lx\n", __func__,
                    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
                    (u_long) ntohl(sav->spi)));
                goto bad;
        }

        /* Restore the Next Protocol field */
        m_copyback(m, protoff, sizeof (u_int8_t), (u_int8_t *) &nproto);

        switch (saidx->dst.sa.sa_family) {
#ifdef INET6
        case AF_INET6:
                error = ipsec6_common_input_cb(m, sav, skip, protoff,
                    &sahtree_tracker);
                break;
#endif
#ifdef INET
        case AF_INET:
                error = ipsec4_common_input_cb(m, sav, skip, protoff,
                    &sahtree_tracker);
                break;
#endif
        default:
                panic("%s: Unexpected address family: %d saidx=%p", __func__,
                    saidx->dst.sa.sa_family, saidx);
        }
        CURVNET_RESTORE();
        return error;
bad:
        ipsec_sahtree_runlock(&sahtree_tracker);
        CURVNET_RESTORE();
        if (sav != NULL)
                key_freesav(&sav);
        if (m != NULL)
                m_freem(m);
        if (xd != NULL)
                free(xd, M_IPCOMP);
        if (crp != NULL)
                crypto_freereq(crp);
        return error;
}

/*
 * IPComp output routine, called by ipsec[46]_perform_request()
 */
static int
ipcomp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
    u_int idx, int skip, int protoff)
{
        IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
        const struct comp_algo *ipcompx;
        struct cryptop *crp;
        struct xform_data *xd;
        crypto_session_t cryptoid;
        int error, ralen, maxpacketsize;

        SECASVAR_RLOCK_TRACKER;

        IPSEC_ASSERT(sav != NULL, ("null SA"));
        ipcompx = sav->tdb_compalgxform;
        IPSEC_ASSERT(ipcompx != NULL, ("null compression xform"));

        /*
         * Do not touch the packet in case our payload to compress
         * is lower than the minimal threshold of the compression
         * alogrithm.  We will just send out the data uncompressed.
         * See RFC 3173, 2.2. Non-Expansion Policy.
         */
        if (m->m_pkthdr.len <= ipcompx->minlen) {
                IPCOMPSTAT_INC(ipcomps_threshold);
                return ipsec_process_done(m, sp, sav, idx);
        }

        ralen = m->m_pkthdr.len - skip; /* Raw payload length before comp. */
        IPCOMPSTAT_INC(ipcomps_output);

        /* 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:
                IPCOMPSTAT_INC(ipcomps_nopf);
                DPRINTF(("%s: unknown/unsupported protocol family %d, "
                    "IPCA %s/%08lx\n", __func__,
                    sav->sah->saidx.dst.sa.sa_family,
                    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
                    (u_long) ntohl(sav->spi)));
                error = EPFNOSUPPORT;
                goto bad;
        }
        if (ralen + skip + IPCOMP_HLENGTH > maxpacketsize) {
                IPCOMPSTAT_INC(ipcomps_toobig);
                DPRINTF(("%s: packet in IPCA %s/%08lx got too big "
                    "(len %u, max len %u)\n", __func__,
                    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
                    (u_long) ntohl(sav->spi),
                    ralen + skip + IPCOMP_HLENGTH, maxpacketsize));
                error = EMSGSIZE;
                goto bad;
        }

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

        m = m_unshare(m, M_NOWAIT);
        if (m == NULL) {
                IPCOMPSTAT_INC(ipcomps_hdrops);
                DPRINTF(("%s: cannot clone mbuf chain, IPCA %s/%08lx\n",
                    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
                    sizeof(buf)), (u_long) ntohl(sav->spi)));
                error = ENOBUFS;
                goto bad;
        }

        /* Ok now, we can pass to the crypto processing. */
        SECASVAR_RLOCK(sav);
        cryptoid = sav->tdb_cryptoid;
        SECASVAR_RUNLOCK(sav);

        /* Get crypto descriptors */
        crp = crypto_getreq(cryptoid, M_NOWAIT);
        if (crp == NULL) {
                IPCOMPSTAT_INC(ipcomps_crypto);
                DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__));
                error = ENOBUFS;
                goto bad;
        }

        /* Compression descriptor */
        crp->crp_op = CRYPTO_OP_COMPRESS;
        crp->crp_payload_start = skip;
        crp->crp_payload_length = ralen;

        /* IPsec-specific opaque crypto info */
        xd =  malloc(sizeof(struct xform_data), M_IPCOMP, M_NOWAIT | M_ZERO);
        if (xd == NULL) {
                IPCOMPSTAT_INC(ipcomps_crypto);
                DPRINTF(("%s: failed to allocate xform_data\n", __func__));
                crypto_freereq(crp);
                error = ENOBUFS;
                goto bad;
        }

        xd->sp = sp;
        xd->sav = sav;
        xd->idx = idx;
        xd->skip = skip;
        xd->protoff = protoff;
        xd->vnet = curvnet;
        xd->cryptoid = cryptoid;

        /* Crypto operation descriptor */
        crp->crp_flags = CRYPTO_F_CBIFSYNC;
        crypto_use_mbuf(crp, m);
        crp->crp_callback = ipcomp_output_cb;
        crp->crp_opaque = xd;

        return crypto_dispatch(crp);
bad:
        if (m)
                m_freem(m);
        key_freesav(&sav);
        key_freesp(&sp);
        return (error);
}

/*
 * IPComp output callback from the crypto driver.
 */
static int
ipcomp_output_cb(struct cryptop *crp)
{
        IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
        struct xform_data *xd;
        struct secpolicy *sp;
        struct secasvar *sav;
        struct mbuf *m;
        crypto_session_t cryptoid;
        u_int idx;
        int error, skip, protoff;

        m = crp->crp_buf.cb_mbuf;
        xd = crp->crp_opaque;
        CURVNET_SET(xd->vnet);
        idx = xd->idx;
        sp = xd->sp;
        sav = xd->sav;
        skip = xd->skip;
        protoff = xd->protoff;
        cryptoid = xd->cryptoid;

        /* Check for crypto errors */
        if (crp->crp_etype) {
                if (crp->crp_etype == EAGAIN) {
                        /* Reset the session ID */
                        if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
                                crypto_freesession(cryptoid);
                        xd->cryptoid = crp->crp_session;
                        CURVNET_RESTORE();
                        return (crypto_dispatch(crp));
                }
                IPCOMPSTAT_INC(ipcomps_noxform);
                DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
                error = crp->crp_etype;
                goto bad;
        }
        /* Shouldn't happen... */
        if (m == NULL) {
                IPCOMPSTAT_INC(ipcomps_crypto);
                DPRINTF(("%s: bogus return buffer from crypto\n", __func__));
                error = EINVAL;
                goto bad;
        }
        IPCOMPSTAT_INC2(ipcomps_hist, sav->alg_comp);

        if (crp->crp_payload_length > crp->crp_olen) {
                struct mbuf *mo;
                struct ipcomp *ipcomp;
                int roff;
                uint8_t prot;

                /* Compression helped, inject IPCOMP header. */
                mo = m_makespace(m, skip, IPCOMP_HLENGTH, &roff);
                if (mo == NULL) {
                        IPCOMPSTAT_INC(ipcomps_wrap);
                        DPRINTF(("%s: IPCOMP header inject failed "
                            "for IPCA %s/%08lx\n",
                            __func__, ipsec_address(&sav->sah->saidx.dst, buf,
                            sizeof(buf)), (u_long) ntohl(sav->spi)));
                        error = ENOBUFS;
                        goto bad;
                }
                ipcomp = (struct ipcomp *)(mtod(mo, caddr_t) + roff);

                /* Initialize the IPCOMP header */
                /* XXX alignment always correct? */
                switch (sav->sah->saidx.dst.sa.sa_family) {
#ifdef INET
                case AF_INET:
                        ipcomp->comp_nxt = mtod(m, struct ip *)->ip_p;
                        break;
#endif /* INET */
#ifdef INET6
                case AF_INET6:
                        ipcomp->comp_nxt = mtod(m, struct ip6_hdr *)->ip6_nxt;
                        break;
#endif
                }
                ipcomp->comp_flags = 0;
                ipcomp->comp_cpi = htons((u_int16_t) ntohl(sav->spi));

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

                /* Adjust the length in the IP header */
                switch (sav->sah->saidx.dst.sa.sa_family) {
#ifdef INET
                case AF_INET:
                        mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
                        break;
#endif /* INET */
#ifdef INET6
                case AF_INET6:
                        mtod(m, struct ip6_hdr *)->ip6_plen =
                                htons(m->m_pkthdr.len) - sizeof(struct ip6_hdr);
                        break;
#endif /* INET6 */
                default:
                        IPCOMPSTAT_INC(ipcomps_nopf);
                        DPRINTF(("%s: unknown/unsupported protocol "
                            "family %d, IPCA %s/%08lx\n", __func__,
                            sav->sah->saidx.dst.sa.sa_family,
                            ipsec_address(&sav->sah->saidx.dst, buf,
                                sizeof(buf)), (u_long) ntohl(sav->spi)));
                        error = EPFNOSUPPORT;
                        goto bad;
                }
        } else {
                /* Compression was useless, we have lost time. */
                IPCOMPSTAT_INC(ipcomps_uncompr);
                DPRINTF(("%s: compressions was useless %d <= %d\n",
                    __func__, crp->crp_payload_length, crp->crp_olen));
                /* XXX remember state to not compress the next couple
                 *     of packets, RFC 3173, 2.2. Non-Expansion Policy */
        }

        /* Release the crypto descriptor */
        free(xd, M_IPCOMP);
        crypto_freereq(crp);

        /* NB: m is reclaimed by ipsec_process_done. */
        error = ipsec_process_done(m, sp, sav, idx);
        CURVNET_RESTORE();
        return (error);
bad:
        if (m)
                m_freem(m);
        CURVNET_RESTORE();
        free(xd, M_IPCOMP);
        crypto_freereq(crp);
        key_freesav(&sav);
        key_freesp(&sp);
        return (error);
}

#ifdef INET
static int
ipcomp4_nonexp_encapcheck(const struct mbuf *m, int off, int proto,
    void *arg __unused)
{
        union sockaddr_union src, dst;
        const struct ip *ip;

        if (V_ipcomp_enable == 0)
                return (0);
        if (proto != IPPROTO_IPV4 && proto != IPPROTO_IPV6)
                return (0);
        bzero(&src, sizeof(src));
        bzero(&dst, sizeof(dst));
        src.sa.sa_family = dst.sa.sa_family = AF_INET;
        src.sin.sin_len = dst.sin.sin_len = sizeof(struct sockaddr_in);
        ip = mtod(m, const struct ip *);
        src.sin.sin_addr = ip->ip_src;
        dst.sin.sin_addr = ip->ip_dst;
        return (ipcomp_encapcheck(&src, &dst));
}

static const struct encaptab *ipe4_cookie = NULL;
static const struct encap_config ipv4_encap_cfg = {
        .proto = -1,
        .min_length = sizeof(struct ip),
        .exact_match = sizeof(in_addr_t) << 4,
        .check = ipcomp4_nonexp_encapcheck,
        .input = ipcomp_nonexp_input
};
#endif
#ifdef INET6
static int
ipcomp6_nonexp_encapcheck(const struct mbuf *m, int off, int proto,
    void *arg __unused)
{
        union sockaddr_union src, dst;
        const struct ip6_hdr *ip6;

        if (V_ipcomp_enable == 0)
                return (0);
        if (proto != IPPROTO_IPV4 && proto != IPPROTO_IPV6)
                return (0);
        bzero(&src, sizeof(src));
        bzero(&dst, sizeof(dst));
        src.sa.sa_family = dst.sa.sa_family = AF_INET;
        src.sin6.sin6_len = dst.sin6.sin6_len = sizeof(struct sockaddr_in6);
        ip6 = mtod(m, const struct ip6_hdr *);
        src.sin6.sin6_addr = ip6->ip6_src;
        dst.sin6.sin6_addr = ip6->ip6_dst;
        if (IN6_IS_SCOPE_LINKLOCAL(&src.sin6.sin6_addr)) {
                /* XXX: sa6_recoverscope() */
                src.sin6.sin6_scope_id =
                    ntohs(src.sin6.sin6_addr.s6_addr16[1]);
                src.sin6.sin6_addr.s6_addr16[1] = 0;
        }
        if (IN6_IS_SCOPE_LINKLOCAL(&dst.sin6.sin6_addr)) {
                /* XXX: sa6_recoverscope() */
                dst.sin6.sin6_scope_id =
                    ntohs(dst.sin6.sin6_addr.s6_addr16[1]);
                dst.sin6.sin6_addr.s6_addr16[1] = 0;
        }
        return (ipcomp_encapcheck(&src, &dst));
}

static const struct encaptab *ipe6_cookie = NULL;
static const struct encap_config ipv6_encap_cfg = {
        .proto = -1,
        .min_length = sizeof(struct ip6_hdr),
        .exact_match = sizeof(struct in6_addr) << 4,
        .check = ipcomp6_nonexp_encapcheck,
        .input = ipcomp_nonexp_input
};
#endif

static struct xformsw ipcomp_xformsw = {
        .xf_type =      XF_IPCOMP,
        .xf_name =      "IPcomp",
        .xf_init =      ipcomp_init,
        .xf_cleanup =   ipcomp_cleanup,
        .xf_input =     ipcomp_input,
        .xf_output =    ipcomp_output,
};

static void
ipcomp_attach(void *dummy __unused)
{

#ifdef INET
        ipe4_cookie = ip_encap_attach(&ipv4_encap_cfg, NULL, M_WAITOK);
#endif
#ifdef INET6
        ipe6_cookie = ip6_encap_attach(&ipv6_encap_cfg, NULL, M_WAITOK);
#endif
        xform_attach(&ipcomp_xformsw);
}

static void
ipcomp_detach(void *dummy __unused)
{

#ifdef INET
        ip_encap_detach(ipe4_cookie);
#endif
#ifdef INET6
        ip6_encap_detach(ipe6_cookie);
#endif
        xform_detach(&ipcomp_xformsw);
}

SYSINIT(ipcomp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
    ipcomp_attach, NULL);
SYSUNINIT(ipcomp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
    ipcomp_detach, NULL);