/*      $NetBSD: xform_ipcomp.c,v 1.76 2024/07/05 04:31:54 rin Exp $    */
/*      $FreeBSD: xform_ipcomp.c,v 1.1.4.1 2003/01/24 05:11:36 sam Exp $        */
/* $OpenBSD: ip_ipcomp.c,v 1.1 2001/07/05 12:08:52 jjbg Exp $ */

/*
 * 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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: xform_ipcomp.c,v 1.76 2024/07/05 04:31:54 rin Exp $");

/* IP payload compression protocol (IPComp), see RFC 2393 */
#if defined(_KERNEL_OPT)
#include "opt_inet.h"
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/kernel.h>
#include <sys/protosw.h>
#include <sys/sysctl.h>
#include <sys/pool.h>
#include <sys/pserialize.h>

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

#include <net/route.h>
#include <netipsec/ipsec.h>
#include <netipsec/ipsec_private.h>
#include <netipsec/xform.h>

#ifdef INET6
#include <netinet/ip6.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>

percpu_t *ipcompstat_percpu;

int ipcomp_enable = 1;

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

const uint8_t ipcomp_stats[256] = { SADB_CALG_STATS_INIT };

static pool_cache_t ipcomp_tdb_crypto_pool_cache;

const struct comp_algo *
ipcomp_algorithm_lookup(int alg)
{
        switch (alg) {
        case SADB_X_CALG_DEFLATE:
                return &comp_algo_deflate_nogrow;
        }
        return NULL;
}

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

        /* NB: algorithm really comes in alg_enc and not alg_comp! */
        tcomp = ipcomp_algorithm_lookup(sav->alg_enc);
        if (tcomp == NULL) {
                DPRINTF("unsupported compression algorithm %d\n",
                    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(&cric, 0, sizeof(cric));
        cric.cri_alg = sav->tdb_compalgxform->type;

        ses = crypto_newsession(&sav->tdb_cryptoid, &cric, crypto_support);
        return ses;
}

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

        crypto_freesession(sav->tdb_cryptoid);
        sav->tdb_cryptoid = 0;
}

/*
 * ipcomp_input() gets called to uncompress an input packet
 */
static int
ipcomp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
{
        struct tdb_crypto *tc;
        struct cryptodesc *crdc;
        struct cryptop *crp;
        int error, hlen = IPCOMP_HLENGTH, stat = IPCOMP_STAT_CRYPTO;

        KASSERT(skip + hlen <= m->m_pkthdr.len);

        /* Get crypto descriptors */
        crp = crypto_getreq(1);
        if (crp == NULL) {
                DPRINTF("no crypto descriptors\n");
                error = ENOBUFS;
                goto error_m;
        }
        /* Get IPsec-specific opaque pointer */
        tc = pool_cache_get(ipcomp_tdb_crypto_pool_cache, PR_NOWAIT);
        if (tc == NULL) {
                DPRINTF("cannot allocate tdb_crypto\n");
                error = ENOBUFS;
                goto error_crp;
        }

        error = m_makewritable(&m, 0, m->m_pkthdr.len, M_NOWAIT);
        if (error) {
                DPRINTF("m_makewritable failed\n");
                goto error_tc;
        }

    {
        int s = pserialize_read_enter();

        /*
         * Take another reference to the SA for opencrypto callback.
         */
        if (__predict_false(sav->state == SADB_SASTATE_DEAD)) {
                pserialize_read_exit(s);
                stat = IPCOMP_STAT_NOTDB;
                error = ENOENT;
                goto error_tc;
        }
        KEY_SA_REF(sav);
        pserialize_read_exit(s);
    }

        crdc = crp->crp_desc;

        crdc->crd_skip = skip + hlen;
        crdc->crd_len = m->m_pkthdr.len - (skip + hlen);
        crdc->crd_inject = 0; /* unused */

        /* Decompression operation */
        crdc->crd_alg = sav->tdb_compalgxform->type;

        /* Crypto operation descriptor */
        crp->crp_ilen = m->m_pkthdr.len - (skip + hlen);
        crp->crp_olen = MCLBYTES; /* hint to decompression code */
        crp->crp_flags = CRYPTO_F_IMBUF;
        crp->crp_buf = m;
        crp->crp_callback = ipcomp_input_cb;
        crp->crp_sid = sav->tdb_cryptoid;
        crp->crp_opaque = tc;

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

        crypto_dispatch(crp);
        return 0;

error_tc:
        pool_cache_put(ipcomp_tdb_crypto_pool_cache, tc);
error_crp:
        crypto_freereq(crp);
error_m:
        m_freem(m);
        IPCOMP_STATINC(stat);
        return error;
}

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

/*
 * IPComp input callback from the crypto driver.
 */
static void
ipcomp_input_cb(struct cryptop *crp)
{
        char buf[IPSEC_ADDRSTRLEN];
        struct tdb_crypto *tc;
        int skip, protoff;
        struct mbuf *m;
        struct secasvar *sav;
        struct secasindex *saidx __diagused;
        int hlen = IPCOMP_HLENGTH, clen;
        uint8_t nproto;
        struct ipcomp *ipc;
        IPSEC_DECLARE_LOCK_VARIABLE;

        KASSERT(crp->crp_opaque != NULL);
        tc = crp->crp_opaque;
        skip = tc->tc_skip;
        protoff = tc->tc_protoff;
        m = crp->crp_buf;

        IPSEC_ACQUIRE_GLOBAL_LOCKS();

        sav = tc->tc_sav;
        saidx = &sav->sah->saidx;
        KASSERTMSG(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) {
                /* Reset the session ID */
                if (sav->tdb_cryptoid != 0)
                        sav->tdb_cryptoid = crp->crp_sid;

                IPCOMP_STATINC(IPCOMP_STAT_NOXFORM);
                DPRINTF("crypto error %d\n", crp->crp_etype);
                goto bad;
        }

        IPCOMP_STATINC(IPCOMP_STAT_HIST + ipcomp_stats[sav->alg_comp]);

        /* Update the counters */
        IPCOMP_STATADD(IPCOMP_STAT_IBYTES, m->m_pkthdr.len - skip - hlen);

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

        /* Release the crypto descriptors */
        pool_cache_put(ipcomp_tdb_crypto_pool_cache, tc);
        tc = 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;

        /*
         * Get the next protocol field.
         *
         * XXX: Really, we should use m_copydata instead of m_pullup.
         */
        if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == 0) {
                IPCOMP_STATINC(IPCOMP_STAT_HDROPS);
                DPRINTF("m_pullup failed\n");
                goto bad;
        }
        ipc = (struct ipcomp *)(mtod(m, uint8_t *) + skip);
        nproto = ipc->comp_nxt;

        switch (nproto) {
        case IPPROTO_IPCOMP:
        case IPPROTO_AH:
        case IPPROTO_ESP:
                IPCOMP_STATINC(IPCOMP_STAT_HDROPS);
                DPRINTF("nested ipcomp, IPCA %s/%08lx\n",
                    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
                    (u_long) ntohl(sav->spi));
                goto bad;
        default:
                break;
        }

        /* Remove the IPCOMP header */
        if (m_striphdr(m, skip, hlen) != 0) {
                IPCOMP_STATINC(IPCOMP_STAT_HDROPS);
                DPRINTF("bad mbuf chain, IPCA %s/%08lx\n",
                    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(nproto), &nproto);

        IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff);

        KEY_SA_UNREF(&sav);
        IPSEC_RELEASE_GLOBAL_LOCKS();
        return;

bad:
        if (sav)
                KEY_SA_UNREF(&sav);
        IPSEC_RELEASE_GLOBAL_LOCKS();
        m_freem(m);
        if (tc != NULL)
                pool_cache_put(ipcomp_tdb_crypto_pool_cache, tc);
        if (crp)
                crypto_freereq(crp);
}

/*
 * IPComp output routine, called by ipsec[46]_process_packet()
 */
static int
ipcomp_output(struct mbuf *m, const struct ipsecrequest *isr,
    struct secasvar *sav, int skip, int protoff, int flags)
{
        char buf[IPSEC_ADDRSTRLEN];
        const struct comp_algo *ipcompx;
        int error, ralen, hlen, maxpacketsize;
        struct cryptodesc *crdc;
        struct cryptop *crp;
        struct tdb_crypto *tc;

        KASSERT(sav != NULL);
        KASSERT(sav->tdb_compalgxform != NULL);
        ipcompx = sav->tdb_compalgxform;

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

        /* Don't process the packet if it is too short */
        if (ralen < ipcompx->minlen) {
                IPCOMP_STATINC(IPCOMP_STAT_MINLEN);
                return ipsec_process_done(m, isr, sav, 0);
        }

        hlen = IPCOMP_HLENGTH;

        IPCOMP_STATINC(IPCOMP_STAT_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
#ifdef INET6
        case AF_INET6:
                maxpacketsize = IPV6_MAXPACKET;
                break;
#endif
        default:
                IPCOMP_STATINC(IPCOMP_STAT_NOPF);
                DPRINTF("unknown/unsupported protocol family %d"
                    ", IPCA %s/%08lx\n",
                    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 (skip + hlen + ralen > maxpacketsize) {
                IPCOMP_STATINC(IPCOMP_STAT_TOOBIG);
                DPRINTF("packet in IPCA %s/%08lx got too big "
                    "(len %u, max len %u)\n",
                    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
                    (u_long) ntohl(sav->spi),
                    skip + hlen + ralen, maxpacketsize);
                error = EMSGSIZE;
                goto bad;
        }

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

        m = m_clone(m);
        if (m == NULL) {
                IPCOMP_STATINC(IPCOMP_STAT_HDROPS);
                DPRINTF("cannot clone mbuf chain, IPCA %s/%08lx\n",
                    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 */

        /* Get crypto descriptors */
        crp = crypto_getreq(1);
        if (crp == NULL) {
                IPCOMP_STATINC(IPCOMP_STAT_CRYPTO);
                DPRINTF("failed to acquire crypto descriptor\n");
                error = ENOBUFS;
                goto bad;
        }
        crdc = crp->crp_desc;

        /* Compression descriptor */
        crdc->crd_skip = skip;
        crdc->crd_len = m->m_pkthdr.len - skip;
        crdc->crd_flags = CRD_F_COMP;
        crdc->crd_inject = skip;

        /* Compression operation */
        crdc->crd_alg = ipcompx->type;

        /* IPsec-specific opaque crypto info */
        tc = pool_cache_get(ipcomp_tdb_crypto_pool_cache, PR_NOWAIT);
        if (tc == NULL) {
                IPCOMP_STATINC(IPCOMP_STAT_CRYPTO);
                DPRINTF("failed to allocate tdb_crypto\n");
                crypto_freereq(crp);
                error = ENOBUFS;
                goto bad;
        }

    {
        int s = pserialize_read_enter();

        /*
         * Take another reference to the SP and the SA for opencrypto callback.
         */
        if (__predict_false(isr->sp->state == IPSEC_SPSTATE_DEAD ||
            sav->state == SADB_SASTATE_DEAD)) {
                pserialize_read_exit(s);
                pool_cache_put(ipcomp_tdb_crypto_pool_cache, tc);
                crypto_freereq(crp);
                IPCOMP_STATINC(IPCOMP_STAT_NOTDB);
                error = ENOENT;
                goto bad;
        }
        KEY_SP_REF(isr->sp);
        KEY_SA_REF(sav);
        pserialize_read_exit(s);
    }

        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;
        tc->tc_flags = flags;
        tc->tc_sav = sav;

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

        crypto_dispatch(crp);
        return 0;

bad:
        m_freem(m);
        return error;
}

/*
 * IPComp output callback from the crypto driver.
 */
static void
ipcomp_output_cb(struct cryptop *crp)
{
        char buf[IPSEC_ADDRSTRLEN];
        struct tdb_crypto *tc;
        const struct ipsecrequest *isr;
        struct secasvar *sav;
        struct mbuf *m, *mo;
        int skip, rlen, roff, flags;
        uint8_t prot;
        uint16_t cpi;
        struct ipcomp * ipcomp;
        IPSEC_DECLARE_LOCK_VARIABLE;

        KASSERT(crp->crp_opaque != NULL);
        tc = crp->crp_opaque;
        m = crp->crp_buf;
        skip = tc->tc_skip;
        rlen = crp->crp_ilen - skip;

        IPSEC_ACQUIRE_GLOBAL_LOCKS();

        isr = tc->tc_isr;
        sav = tc->tc_sav;

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

                IPCOMP_STATINC(IPCOMP_STAT_NOXFORM);
                DPRINTF("crypto error %d\n", crp->crp_etype);
                goto bad;
        }

        IPCOMP_STATINC(IPCOMP_STAT_HIST + ipcomp_stats[sav->alg_comp]);

        if (rlen > crp->crp_olen) {
                /* Inject IPCOMP header */
                mo = m_makespace(m, skip, IPCOMP_HLENGTH, &roff);
                if (mo == NULL) {
                        IPCOMP_STATINC(IPCOMP_STAT_WRAP);
                        DPRINTF("failed to inject IPCOMP header for "
                            "IPCA %s/%08lx\n",
                            ipsec_address(&sav->sah->saidx.dst, buf,
                            sizeof(buf)), (u_long) ntohl(sav->spi));
                        goto bad;
                }
                ipcomp = (struct ipcomp *)(mtod(mo, char *) + 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
#ifdef INET6
                case AF_INET6:
                        ipcomp->comp_nxt = mtod(m, struct ip6_hdr *)->ip6_nxt;
                        break;
#endif
                }
                ipcomp->comp_flags = 0;

                cpi = ntohl(sav->spi) & 0xffff;
                ipcomp->comp_cpi = htons(cpi);

                /* Fix Next Protocol in IPv4/IPv6 header */
                prot = IPPROTO_IPCOMP;
                m_copyback(m, tc->tc_protoff, sizeof(prot), &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
#ifdef INET6
                case AF_INET6:
                        mtod(m, struct ip6_hdr *)->ip6_plen =
                            htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
                        break;
#endif
                default:
                        IPCOMP_STATINC(IPCOMP_STAT_NOPF);
                        DPRINTF("unknown/unsupported protocol "
                            "family %d, IPCA %s/%08lx\n",
                            sav->sah->saidx.dst.sa.sa_family,
                            ipsec_address(&sav->sah->saidx.dst, buf,
                            sizeof(buf)), (u_long) ntohl(sav->spi));
                        goto bad;
                }
        } else {
                /* compression was useless, we have lost time */
                IPCOMP_STATINC(IPCOMP_STAT_USELESS);
                DPRINTF("compression was useless: initial size was %d "
                    "and compressed size is %d\n", rlen, crp->crp_olen);
        }

        flags = tc->tc_flags;
        /* Release the crypto descriptor */
        pool_cache_put(ipcomp_tdb_crypto_pool_cache, tc);
        crypto_freereq(crp);

        /* NB: m is reclaimed by ipsec_process_done. */
        (void)ipsec_process_done(m, isr, sav, flags);
        KEY_SA_UNREF(&sav);
        KEY_SP_UNREF(&isr->sp);
        IPSEC_RELEASE_GLOBAL_LOCKS();
        return;

bad:
        if (sav)
                KEY_SA_UNREF(&sav);
        KEY_SP_UNREF(&isr->sp);
        IPSEC_RELEASE_GLOBAL_LOCKS();
        m_freem(m);
        pool_cache_put(ipcomp_tdb_crypto_pool_cache, tc);
        crypto_freereq(crp);
}

static struct xformsw ipcomp_xformsw = {
        .xf_type        = XF_IPCOMP,
        .xf_flags       = XFT_COMP,
        .xf_name        = "IPcomp",
        .xf_init        = ipcomp_init,
        .xf_zeroize     = ipcomp_zeroize,
        .xf_input       = ipcomp_input,
        .xf_output      = ipcomp_output,
        .xf_next        = NULL,
};

void
ipcomp_attach(void)
{
        ipcompstat_percpu = percpu_alloc(sizeof(uint64_t) * IPCOMP_NSTATS);
        ipcomp_tdb_crypto_pool_cache = pool_cache_init(sizeof(struct tdb_crypto),
            coherency_unit, 0, 0, "ipcomp_tdb_crypto", NULL, IPL_SOFTNET,
            NULL, NULL, NULL);
        xform_register(&ipcomp_xformsw);
}