/*
 * Copyright (C) 2001-2003 by Darren Reed
 *
 * See the IPFILTER.LICENCE file for details on licencing.
 *
 * Simple ISAKMP transparent proxy for in-kernel use.  For use with the NAT
 * code.
 *
 * $Id: ip_ipsec_pxy.c,v 2.20.2.7 2005/07/15 21:56:50 darrenr Exp $
 *
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#define IPF_IPSEC_PROXY

typedef struct ifs_ipsecpxy {
        frentry_t               ipsecfr;
        ipftq_t                 *ipsecnattqe;
        ipftq_t                 *ipsecstatetqe;
        char                    ipsec_buffer[1500];
        int                     ipsec_proxy_init;
        int                     ipsec_proxy_ttl;
} ifs_ipsecpxy_t;

int ippr_ipsec_init __P((void **, ipf_stack_t *));
void ippr_ipsec_fini __P((void **, ipf_stack_t *));
int ippr_ipsec_new __P((fr_info_t *, ap_session_t *, nat_t *, void *));
void ippr_ipsec_del __P((ap_session_t *, void *, ipf_stack_t *));
int ippr_ipsec_inout __P((fr_info_t *, ap_session_t *, nat_t *, void *));
int ippr_ipsec_match __P((fr_info_t *, ap_session_t *, nat_t *, void *));

/*
 * IPSec application proxy initialization.
 */
int ippr_ipsec_init(private, ifs)
void **private;
ipf_stack_t *ifs;
{
        ifs_ipsecpxy_t *ifsipsec;

        KMALLOC(ifsipsec, ifs_ipsecpxy_t *);
        if (ifsipsec == NULL)
                return -1;

        bzero((char *)&ifsipsec->ipsecfr, sizeof(ifsipsec->ipsecfr));
        ifsipsec->ipsecfr.fr_ref = 1;
        ifsipsec->ipsecfr.fr_flags = FR_OUTQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
        MUTEX_INIT(&ifsipsec->ipsecfr.fr_lock, "IPsec proxy rule lock");
        ifsipsec->ipsec_proxy_init = 1;
        ifsipsec->ipsec_proxy_ttl = 60;

        ifsipsec->ipsecnattqe = fr_addtimeoutqueue(&ifs->ifs_nat_utqe, ifsipsec->ipsec_proxy_ttl, ifs);
        if (ifsipsec->ipsecnattqe == NULL) {
                MUTEX_DESTROY(&ifsipsec->ipsecfr.fr_lock);
                KFREE(ifsipsec);
                return -1;
        }
        ifsipsec->ipsecstatetqe = fr_addtimeoutqueue(&ifs->ifs_ips_utqe, ifsipsec->ipsec_proxy_ttl, ifs);
        if (ifsipsec->ipsecstatetqe == NULL) {
                if (fr_deletetimeoutqueue(ifsipsec->ipsecnattqe) == 0)
                        fr_freetimeoutqueue(ifsipsec->ipsecnattqe, ifs);
                ifsipsec->ipsecnattqe = NULL;
                MUTEX_DESTROY(&ifsipsec->ipsecfr.fr_lock);
                KFREE(ifsipsec);
                return -1;
        }

        ifsipsec->ipsecnattqe->ifq_flags |= IFQF_PROXY;
        ifsipsec->ipsecstatetqe->ifq_flags |= IFQF_PROXY;

        ifsipsec->ipsecfr.fr_age[0] = ifsipsec->ipsec_proxy_ttl;
        ifsipsec->ipsecfr.fr_age[1] = ifsipsec->ipsec_proxy_ttl;

        *private = (void *)ifsipsec;

        return 0;
}


void ippr_ipsec_fini(private, ifs)
void **private;
ipf_stack_t *ifs;
{
        ifs_ipsecpxy_t *ifsipsec = *((ifs_ipsecpxy_t **)private);

        if (ifsipsec->ipsecnattqe != NULL) {
                if (fr_deletetimeoutqueue(ifsipsec->ipsecnattqe) == 0)
                        fr_freetimeoutqueue(ifsipsec->ipsecnattqe, ifs);
        }
        ifsipsec->ipsecnattqe = NULL;
        if (ifsipsec->ipsecstatetqe != NULL) {
                if (fr_deletetimeoutqueue(ifsipsec->ipsecstatetqe) == 0)
                        fr_freetimeoutqueue(ifsipsec->ipsecstatetqe, ifs);
        }
        ifsipsec->ipsecstatetqe = NULL;

        if (ifsipsec->ipsec_proxy_init == 1) {
                MUTEX_DESTROY(&ifsipsec->ipsecfr.fr_lock);
                ifsipsec->ipsec_proxy_init = 0;
        }

        KFREE(ifsipsec);
        *private = NULL;
}


/*
 * Setup for a new IPSEC proxy.
 */
int ippr_ipsec_new(fin, aps, nat, private)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
void *private;
{
        ipsec_pxy_t *ipsec;
        fr_info_t fi;
        ipnat_t *ipn;
        char *ptr;
        int p, off, dlen, ttl;
        mb_t *m;
        ip_t *ip;
        ipf_stack_t *ifs = fin->fin_ifs;
        ifs_ipsecpxy_t *ifsipsec = (ifs_ipsecpxy_t *)private;

        off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff;
        bzero(ifsipsec->ipsec_buffer, sizeof(ifsipsec->ipsec_buffer));
        ip = fin->fin_ip;
        m = fin->fin_m;

        dlen = M_LEN(m) - off;
        if (dlen < 16)
                return -1;
        COPYDATA(m, off, MIN(sizeof(ifsipsec->ipsec_buffer), dlen),
                 ifsipsec->ipsec_buffer);

        if (nat_outlookup(fin, 0, IPPROTO_ESP, nat->nat_inip,
                          ip->ip_dst) != NULL)
                return -1;

        aps->aps_psiz = sizeof(*ipsec);
        KMALLOCS(aps->aps_data, ipsec_pxy_t *, sizeof(*ipsec));
        if (aps->aps_data == NULL)
                return -1;

        ipsec = aps->aps_data;
        bzero((char *)ipsec, sizeof(*ipsec));

        /*
         * Create NAT rule against which the tunnel/transport mapping is
         * created.  This is required because the current NAT rule does not
         * describe ESP but UDP instead.
         */
        ipn = &ipsec->ipsc_rule;
        ttl = IPF_TTLVAL(ifsipsec->ipsecnattqe->ifq_ttl);
        ipn->in_tqehead[0] = fr_addtimeoutqueue(&ifs->ifs_nat_utqe, ttl, ifs);
        ipn->in_tqehead[1] = fr_addtimeoutqueue(&ifs->ifs_nat_utqe, ttl, ifs);
        ipn->in_ifps[0] = fin->fin_ifp;
        ipn->in_apr = NULL;
        ipn->in_use = 1;
        ipn->in_hits = 1;
        ipn->in_nip = ntohl(nat->nat_outip.s_addr);
        ipn->in_ippip = 1;
        ipn->in_inip = nat->nat_inip.s_addr;
        ipn->in_inmsk = 0xffffffff;
        ipn->in_outip = fin->fin_saddr;
        ipn->in_outmsk = nat->nat_outip.s_addr;
        ipn->in_srcip = fin->fin_saddr;
        ipn->in_srcmsk = 0xffffffff;
        ipn->in_redir = NAT_MAP;
        bcopy(nat->nat_ptr->in_ifnames[0], ipn->in_ifnames[0],
              sizeof(ipn->in_ifnames[0]));
        ipn->in_p = IPPROTO_ESP;

        bcopy((char *)fin, (char *)&fi, sizeof(fi));
        fi.fin_fi.fi_p = IPPROTO_ESP;
        fi.fin_fr = &ifsipsec->ipsecfr;
        fi.fin_data[0] = 0;
        fi.fin_data[1] = 0;
        p = ip->ip_p;
        ip->ip_p = IPPROTO_ESP;
        fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
        fi.fin_flx |= FI_IGNORE;

        ptr = ifsipsec->ipsec_buffer;
        bcopy(ptr, (char *)ipsec->ipsc_icookie, sizeof(ipsec_cookie_t));
        ptr += sizeof(ipsec_cookie_t);
        bcopy(ptr, (char *)ipsec->ipsc_rcookie, sizeof(ipsec_cookie_t));
        /*
         * The responder cookie should only be non-zero if the initiator
         * cookie is non-zero.  Therefore, it is safe to assume(!) that the
         * cookies are both set after copying if the responder is non-zero.
         */
        if ((ipsec->ipsc_rcookie[0]|ipsec->ipsc_rcookie[1]) != 0)
                ipsec->ipsc_rckset = 1;

        ipsec->ipsc_nat = nat_new(&fi, ipn, &ipsec->ipsc_nat,
                                  NAT_SLAVE|SI_WILDP, NAT_OUTBOUND);
        if (ipsec->ipsc_nat != NULL) {
                (void) nat_proto(&fi, ipsec->ipsc_nat, 0);
                nat_update(&fi, ipsec->ipsc_nat, ipn);

                fi.fin_data[0] = 0;
                fi.fin_data[1] = 0;
                ipsec->ipsc_state = fr_addstate(&fi, &ipsec->ipsc_state,
                                                SI_WILDP);
        }
        ip->ip_p = p & 0xff;
        return 0;
}


/*
 * For outgoing IKE packets.  refresh timeouts for NAT & state entries, if
 * we can.  If they have disappeared, recreate them.
 */
int ippr_ipsec_inout(fin, aps, nat, private)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
void *private;
{
        ipsec_pxy_t *ipsec;
        fr_info_t fi;
        ip_t *ip;
        int p;
        ipf_stack_t *ifs = fin->fin_ifs;
        ifs_ipsecpxy_t *ifsipsec = (ifs_ipsecpxy_t *)private;

        if ((fin->fin_out == 1) && (nat->nat_dir == NAT_INBOUND))
                return 0;

        if ((fin->fin_out == 0) && (nat->nat_dir == NAT_OUTBOUND))
                return 0;

        ipsec = aps->aps_data;

        if (ipsec != NULL) {
                ip = fin->fin_ip;
                p = ip->ip_p;

                if ((ipsec->ipsc_nat == NULL) || (ipsec->ipsc_state == NULL)) {
                        bcopy((char *)fin, (char *)&fi, sizeof(fi));
                        fi.fin_fi.fi_p = IPPROTO_ESP;
                        fi.fin_fr = &ifsipsec->ipsecfr;
                        fi.fin_data[0] = 0;
                        fi.fin_data[1] = 0;
                        ip->ip_p = IPPROTO_ESP;
                        fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
                        fi.fin_flx |= FI_IGNORE;
                }

                /*
                 * Update NAT timeout/create NAT if missing.
                 */
                if (ipsec->ipsc_nat != NULL)
                        fr_queueback(&ipsec->ipsc_nat->nat_tqe, ifs);
                else {
                        ipsec->ipsc_nat = nat_new(&fi, &ipsec->ipsc_rule,
                                                  &ipsec->ipsc_nat,
                                                  NAT_SLAVE|SI_WILDP,
                                                  nat->nat_dir);
                        if (ipsec->ipsc_nat != NULL) {
                                (void) nat_proto(&fi, ipsec->ipsc_nat, 0);
                                nat_update(&fi, ipsec->ipsc_nat,
                                           &ipsec->ipsc_rule);
                        }
                }

                /*
                 * Update state timeout/create state if missing.
                 */
                READ_ENTER(&ifs->ifs_ipf_state);
                if (ipsec->ipsc_state != NULL) {
                        fr_queueback(&ipsec->ipsc_state->is_sti, ifs);
                        ipsec->ipsc_state->is_die = nat->nat_age;
                        RWLOCK_EXIT(&ifs->ifs_ipf_state);
                } else {
                        RWLOCK_EXIT(&ifs->ifs_ipf_state);
                        fi.fin_data[0] = 0;
                        fi.fin_data[1] = 0;
                        ipsec->ipsc_state = fr_addstate(&fi,
                                                        &ipsec->ipsc_state,
                                                        SI_WILDP);
                }
                ip->ip_p = p;
        }
        return 0;
}


/*
 * This extends the NAT matching to be based on the cookies associated with
 * a session and found at the front of IKE packets.  The cookies are always
 * in the same order (not reversed depending on packet flow direction as with
 * UDP/TCP port numbers).
 */
/*ARGSUSED*/
int ippr_ipsec_match(fin, aps, nat, private)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
void *private;
{
        ipsec_pxy_t *ipsec;
        u_32_t cookies[4];
        mb_t *m;
        int off;

        nat = nat;      /* LINT */

        if ((fin->fin_dlen < sizeof(cookies)) || (fin->fin_flx & FI_FRAG))
                return -1;

        off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff;
        ipsec = aps->aps_data;
        m = fin->fin_m;
        COPYDATA(m, off, sizeof(cookies), (char *)cookies);

        if ((cookies[0] != ipsec->ipsc_icookie[0]) ||
            (cookies[1] != ipsec->ipsc_icookie[1]))
                return -1;

        if (ipsec->ipsc_rckset == 0) {
                if ((cookies[2]|cookies[3]) == 0) {
                        return 0;
                }
                ipsec->ipsc_rckset = 1;
                ipsec->ipsc_rcookie[0] = cookies[2];
                ipsec->ipsc_rcookie[1] = cookies[3];
                return 0;
        }

        if ((cookies[2] != ipsec->ipsc_rcookie[0]) ||
            (cookies[3] != ipsec->ipsc_rcookie[1]))
                return -1;
        return 0;
}


/*
 * clean up after ourselves.
 */
/*ARGSUSED*/
void ippr_ipsec_del(aps, private, ifs)
ap_session_t *aps;
void *private;
ipf_stack_t *ifs;
{
        ipsec_pxy_t *ipsec;

        ipsec = aps->aps_data;

        if (ipsec != NULL) {
                /*
                 * Don't bother changing any of the NAT structure details,
                 * *_del() is on a callback from aps_free(), from nat_delete()
                 */

                READ_ENTER(&ifs->ifs_ipf_state);
                if (ipsec->ipsc_state != NULL) {
                        ipsec->ipsc_state->is_die = ifs->ifs_fr_ticks + 1;
                        ipsec->ipsc_state->is_me = NULL;
                        fr_queuefront(&ipsec->ipsc_state->is_sti);
                }
                RWLOCK_EXIT(&ifs->ifs_ipf_state);

                ipsec->ipsc_state = NULL;
                ipsec->ipsc_nat = NULL;
        }
}