/* $OpenBSD: ipsec.c,v 1.155 2025/04/30 03:53:21 tb Exp $        */
/* $EOM: ipsec.c,v 1.143 2000/12/11 23:57:42 niklas Exp $        */

/*
 * Copyright (c) 1998, 1999, 2000, 2001 Niklas Hallqvist.  All rights reserved.
 * Copyright (c) 2001 Angelos D. Keromytis.  All rights reserved.
 * Copyright (c) 2001 Håkan Olsson.  All rights reserved.
 *
 * 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.
 *
 * 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.
 */

/*
 * This code was written under funding by Ericsson Radio Systems.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>

#include <net/if.h>
#include <net/pfvar.h>

#include "attribute.h"
#include "conf.h"
#include "connection.h"
#include "constants.h"
#include "crypto.h"
#include "dh.h"
#include "doi.h"
#include "dpd.h"
#include "exchange.h"
#include "hash.h"
#include "ike_aggressive.h"
#include "ike_auth.h"
#include "ike_main_mode.h"
#include "ike_quick_mode.h"
#include "ipsec.h"
#include "ipsec_doi.h"
#include "isakmp.h"
#include "isakmp_cfg.h"
#include "isakmp_fld.h"
#include "isakmp_num.h"
#include "log.h"
#include "message.h"
#include "nat_traversal.h"
#include "pf_key_v2.h"
#include "prf.h"
#include "sa.h"
#include "timer.h"
#include "transport.h"
#include "util.h"
#include "x509.h"

extern int acquire_only;

#define MINIMUM(a, b)   (((a) < (b)) ? (a) : (b))
#define MAXIMUM(a, b)   (((a) > (b)) ? (a) : (b))

/* The replay window size used for all IPsec protocols if not overridden.  */
#define DEFAULT_REPLAY_WINDOW 16

struct ipsec_decode_arg {
        struct message *msg;
        struct sa      *sa;
        struct proto   *proto;
};

/* These variables hold the contacted peers ADT state.  */
struct contact {
        struct sockaddr *addr;
        socklen_t       len;
}              *contacts = 0;
int             contact_cnt = 0, contact_limit = 0;

static int      addr_cmp(const void *, const void *);
static int      ipsec_add_contact(struct message *);
static int      ipsec_contacted(struct message *);
static int      ipsec_debug_attribute(u_int16_t, u_int8_t *, u_int16_t,
    void *);
static void     ipsec_delete_spi(struct sa *, struct proto *, int);
static int16_t *ipsec_exchange_script(u_int8_t);
static void     ipsec_finalize_exchange(struct message *);
static void     ipsec_free_exchange_data(void *);
static void     ipsec_free_proto_data(void *);
static void     ipsec_free_sa_data(void *);
static struct keystate *ipsec_get_keystate(struct message *);
static u_int8_t *ipsec_get_spi(size_t *, u_int8_t, struct message *);
static int      ipsec_handle_leftover_payload(struct message *, u_int8_t,
    struct payload *);
static int      ipsec_informational_post_hook(struct message *);
static int      ipsec_informational_pre_hook(struct message *);
static int      ipsec_initiator(struct message *);
static void     ipsec_proto_init(struct proto *, char *);
static int      ipsec_responder(struct message *);
static void     ipsec_setup_situation(u_int8_t *);
static int      ipsec_set_network(u_int8_t *, u_int8_t *, struct sa *);
static size_t   ipsec_situation_size(void);
static u_int8_t ipsec_spi_size(u_int8_t);
static int      ipsec_validate_attribute(u_int16_t, u_int8_t *, u_int16_t,
    void *);
static int      ipsec_validate_exchange(u_int8_t);
static int      ipsec_validate_id_information(u_int8_t, u_int8_t *, u_int8_t *,
    size_t, struct exchange *);
static int      ipsec_validate_key_information(u_int8_t *, size_t);
static int      ipsec_validate_notification(u_int16_t);
static int      ipsec_validate_proto(u_int8_t);
static int      ipsec_validate_situation(u_int8_t *, size_t *, size_t);
static int      ipsec_validate_transform_id(u_int8_t, u_int8_t);
static int      ipsec_sa_check_flow(struct sa *, void *);
static int      ipsec_sa_check_flow_any(struct sa *, void *);
static int      ipsec_sa_tag(struct exchange *, struct sa *, struct sa *);
static int      ipsec_sa_iface(struct exchange *, struct sa *, struct sa *);

static struct doi ipsec_doi = {
        {0}, IPSEC_DOI_IPSEC,
        sizeof(struct ipsec_exch), sizeof(struct ipsec_sa),
        sizeof(struct ipsec_proto),
        ipsec_debug_attribute,
        ipsec_delete_spi,
        ipsec_exchange_script,
        ipsec_finalize_exchange,
        ipsec_free_exchange_data,
        ipsec_free_proto_data,
        ipsec_free_sa_data,
        ipsec_get_keystate,
        ipsec_get_spi,
        ipsec_handle_leftover_payload,
        ipsec_informational_post_hook,
        ipsec_informational_pre_hook,
        ipsec_is_attribute_incompatible,
        ipsec_proto_init,
        ipsec_setup_situation,
        ipsec_situation_size,
        ipsec_spi_size,
        ipsec_validate_attribute,
        ipsec_validate_exchange,
        ipsec_validate_id_information,
        ipsec_validate_key_information,
        ipsec_validate_notification,
        ipsec_validate_proto,
        ipsec_validate_situation,
        ipsec_validate_transform_id,
        ipsec_initiator,
        ipsec_responder,
        ipsec_decode_ids
};

int16_t script_quick_mode[] = {
        ISAKMP_PAYLOAD_HASH,    /* Initiator -> responder.  */
        ISAKMP_PAYLOAD_SA,
        ISAKMP_PAYLOAD_NONCE,
        EXCHANGE_SCRIPT_SWITCH,
        ISAKMP_PAYLOAD_HASH,    /* Responder -> initiator.  */
        ISAKMP_PAYLOAD_SA,
        ISAKMP_PAYLOAD_NONCE,
        EXCHANGE_SCRIPT_SWITCH,
        ISAKMP_PAYLOAD_HASH,    /* Initiator -> responder.  */
        EXCHANGE_SCRIPT_END
};

int16_t script_new_group_mode[] = {
        ISAKMP_PAYLOAD_HASH,    /* Initiator -> responder.  */
        ISAKMP_PAYLOAD_SA,
        EXCHANGE_SCRIPT_SWITCH,
        ISAKMP_PAYLOAD_HASH,    /* Responder -> initiator.  */
        ISAKMP_PAYLOAD_SA,
        EXCHANGE_SCRIPT_END
};

struct dst_spi_proto_arg {
        struct sockaddr *dst;
        u_int32_t       spi;
        u_int8_t        proto;
};

/*
 * Check if SA matches what we are asking for through V_ARG.  It has to
 * be a finished phase 2 SA.
 * if "proto" arg is 0, match any proto
 */
static int
ipsec_sa_check(struct sa *sa, void *v_arg)
{
        struct dst_spi_proto_arg *arg = v_arg;
        struct proto   *proto;
        struct sockaddr *dst, *src;
        int             incoming;

        if (sa->phase != 2 || !(sa->flags & SA_FLAG_READY))
                return 0;

        sa->transport->vtbl->get_dst(sa->transport, &dst);
        if (memcmp(sockaddr_addrdata(dst), sockaddr_addrdata(arg->dst),
            sockaddr_addrlen(dst)) == 0)
                incoming = 0;
        else {
                sa->transport->vtbl->get_src(sa->transport, &src);
                if (memcmp(sockaddr_addrdata(src), sockaddr_addrdata(arg->dst),
                    sockaddr_addrlen(src)) == 0)
                        incoming = 1;
                else
                        return 0;
        }

        for (proto = TAILQ_FIRST(&sa->protos); proto;
            proto = TAILQ_NEXT(proto, link))
                if ((arg->proto == 0 || proto->proto == arg->proto) &&
                    memcmp(proto->spi[incoming], &arg->spi, sizeof arg->spi)
                    == 0)
                        return 1;
        return 0;
}

/* Find an SA with a "name" of DST, SPI & PROTO.  */
struct sa *
ipsec_sa_lookup(struct sockaddr *dst, u_int32_t spi, u_int8_t proto)
{
        struct dst_spi_proto_arg arg;

        arg.dst = dst;
        arg.spi = spi;
        arg.proto = proto;
        return sa_find(ipsec_sa_check, &arg);
}

/*
 * Check if SA matches the flow of another SA in V_ARG.  It has to
 * be a finished non-replaced phase 2 SA.
 * XXX At some point other selectors will matter here too.
 */
static int
ipsec_sa_check_flow(struct sa *sa, void *v_arg)
{
        if ((sa->flags & (SA_FLAG_READY | SA_FLAG_REPLACED)) != SA_FLAG_READY)
                return 0;

        return ipsec_sa_check_flow_any(sa, v_arg);
}

static int
ipsec_sa_check_flow_any(struct sa *sa, void *v_arg)
{
        struct sa      *sa2 = v_arg;
        struct ipsec_sa *isa = sa->data, *isa2 = sa2->data;

        if (sa == sa2 || sa->phase != 2 ||
            (sa->flags & SA_FLAG_READY) != SA_FLAG_READY)
                return 0;

        if (isa->tproto != isa2->tproto || isa->sport != isa2->sport ||
            isa->dport != isa2->dport)
                return 0;

        if ((sa->flags & SA_FLAG_IFACE) != (sa2->flags & SA_FLAG_IFACE))
                return 0;

        if (sa->flags & SA_FLAG_IFACE)
                return sa->iface == sa2->iface;

        /*
         * If at least one of the IPsec SAs is incomplete, we're done.
         */
        if (isa->src_net == NULL || isa2->src_net == NULL ||
            isa->dst_net == NULL || isa2->dst_net == NULL ||
            isa->src_mask == NULL || isa2->src_mask == NULL ||
            isa->dst_mask == NULL || isa2->dst_mask == NULL)
                return 0;

        return isa->src_net->sa_family == isa2->src_net->sa_family &&
            memcmp(sockaddr_addrdata(isa->src_net),
            sockaddr_addrdata(isa2->src_net),
            sockaddr_addrlen(isa->src_net)) == 0 &&
            memcmp(sockaddr_addrdata(isa->src_mask),
            sockaddr_addrdata(isa2->src_mask),
            sockaddr_addrlen(isa->src_mask)) == 0 &&
            memcmp(sockaddr_addrdata(isa->dst_net),
            sockaddr_addrdata(isa2->dst_net),
            sockaddr_addrlen(isa->dst_net)) == 0 &&
            memcmp(sockaddr_addrdata(isa->dst_mask),
            sockaddr_addrdata(isa2->dst_mask),
            sockaddr_addrlen(isa->dst_mask)) == 0;
}

/*
 * Construct a PF tag if specified in the configuration.
 * It is possible to use variables to expand the tag:
 * $id          The string representation of the remote ID
 * $domain      The stripped domain part of the ID (for FQDN and UFQDN)
 */
static int
ipsec_sa_tag(struct exchange *exchange, struct sa *sa, struct sa *isakmp_sa)
{
        char *format, *section;
        char *id_string = NULL, *domain = NULL;
        int error = -1;
        size_t len;

        sa->tag = NULL;

        if (exchange->name == NULL ||
            (section = exchange->name) == NULL ||
            (format = conf_get_str(section, "PF-Tag")) == NULL)
                return (0);     /* ignore if not present */

        len = PF_TAG_NAME_SIZE;
        if ((sa->tag = calloc(1, len)) == NULL) {
                log_error("ipsec_sa_tag: calloc");
                goto fail;
        }
        if (strlcpy(sa->tag, format, len) >= len) {
                log_print("ipsec_sa_tag: tag too long");
                goto fail;
        }
        if (isakmp_sa->initiator)
                id_string = ipsec_id_string(isakmp_sa->id_r,
                    isakmp_sa->id_r_len);
        else
                id_string = ipsec_id_string(isakmp_sa->id_i,
                    isakmp_sa->id_i_len);

        if (strstr(format, "$id") != NULL) {
                if (id_string == NULL) {
                        log_print("ipsec_sa_tag: cannot get ID");
                        goto fail;
                }
                if (expand_string(sa->tag, len, "$id", id_string) != 0) {
                        log_print("ipsec_sa_tag: failed to expand tag");
                        goto fail;
                }
        }

        if (strstr(format, "$domain") != NULL) {
                if (id_string == NULL) {
                        log_print("ipsec_sa_tag: cannot get ID");
                        goto fail;
                }
                if (strncmp(id_string, "fqdn/", strlen("fqdn/")) == 0)
                        domain = strchr(id_string, '.');
                else if (strncmp(id_string, "ufqdn/", strlen("ufqdn/")) == 0)
                        domain = strchr(id_string, '@');
                if (domain == NULL || strlen(domain) < 2) {
                        log_print("ipsec_sa_tag: no valid domain in ID %s",
                            id_string);
                        goto fail;
                }
                domain++;
                if (expand_string(sa->tag, len, "$domain", domain) != 0) {
                        log_print("ipsec_sa_tag: failed to expand tag");
                        goto fail;
                }
        }

        LOG_DBG((LOG_SA, 10, "ipsec_sa_tag: tag_len %ld tag \"%s\"",
            strlen(sa->tag), sa->tag));

        error = 0;
 fail:
        free(id_string);
        if (error != 0) {
                free(sa->tag);
                sa->tag = NULL;
        }

        return (error);
}

static int
ipsec_sa_iface(struct exchange *exchange, struct sa *sa, struct sa *isakmp_sa)
{
        char *section, *value;
        const char *errstr = NULL;

        if (exchange->name == NULL ||
            (section = exchange->name) == NULL ||
            (value = conf_get_str(section, "Interface")) == NULL)
                return (0);     /* ignore if not present */

        sa->iface = strtonum(value, 0, UINT_MAX, &errstr);
        if (errstr != NULL) {
                log_error("[%s]:Interface %s", section, errstr);
                return (-1);
        }

        sa->flags |= SA_FLAG_IFACE;

        return (0);
}

/*
 * Do IPsec DOI specific finalizations task for the exchange where MSG was
 * the final message.
 */
static void
ipsec_finalize_exchange(struct message *msg)
{
        struct sa      *isakmp_sa = msg->isakmp_sa;
        struct ipsec_sa *isa;
        struct exchange *exchange = msg->exchange;
        struct ipsec_exch *ie = exchange->data;
        struct sa      *sa = 0, *old_sa;
        struct proto   *proto, *last_proto = 0;
        char           *addr1, *addr2, *mask1, *mask2;

        switch (exchange->phase) {
        case 1:
                switch (exchange->type) {
                case ISAKMP_EXCH_ID_PROT:
                case ISAKMP_EXCH_AGGRESSIVE:
                        isa = isakmp_sa->data;
                        isa->hash = ie->hash->type;
                        isa->prf_type = ie->prf_type;
                        isa->skeyid_len = ie->skeyid_len;
                        isa->skeyid_d = ie->skeyid_d;
                        isa->skeyid_a = ie->skeyid_a;
                        /* Prevents early free of SKEYID_*.  */
                        ie->skeyid_a = ie->skeyid_d = 0;

                        /*
                         * If a lifetime was negotiated setup the expiration
                         * timers.
                         */
                        if (isakmp_sa->seconds)
                                sa_setup_expirations(isakmp_sa);

                        if (isakmp_sa->flags & SA_FLAG_NAT_T_KEEPALIVE)
                                nat_t_setup_keepalive(isakmp_sa);
                        break;
                }
                break;

        case 2:
                switch (exchange->type) {
                case IKE_EXCH_QUICK_MODE:
                        /*
                         * Tell the application(s) about the SPIs and key
                         * material.
                         */
                        for (sa = TAILQ_FIRST(&exchange->sa_list); sa;
                            sa = TAILQ_NEXT(sa, next)) {
                                isa = sa->data;

                                if (exchange->initiator) {
                                        /*
                                         * Initiator is source, responder is
                                         * destination.
                                         */
                                        if (ipsec_set_network(ie->id_ci,
                                            ie->id_cr, sa)) {
                                                log_print(
                                                    "ipsec_finalize_exchange: "
                                                    "ipsec_set_network "
                                                    "failed");
                                                return;
                                        }
                                } else {
                                        /*
                                         * Responder is source, initiator is
                                         * destination.
                                         */
                                        if (ipsec_set_network(ie->id_cr,
                                            ie->id_ci, sa)) {
                                                log_print(
                                                    "ipsec_finalize_exchange: "
                                                    "ipsec_set_network "
                                                    "failed");
                                                return;
                                        }
                                }

                                if (ipsec_sa_tag(exchange, sa, isakmp_sa) == -1)
                                        return;

                                if (ipsec_sa_iface(exchange, sa, isakmp_sa) == -1)
                                        return;

                                for (proto = TAILQ_FIRST(&sa->protos),
                                    last_proto = 0; proto;
                                    proto = TAILQ_NEXT(proto, link)) {
                                        if (pf_key_v2_set_spi(sa, proto,
                                            0, isakmp_sa) ||
                                            (last_proto &&
                                            pf_key_v2_group_spis(sa,
                                                last_proto, proto, 0)) ||
                                            pf_key_v2_set_spi(sa, proto,
                                                1, isakmp_sa) ||
                                            (last_proto &&
                                                pf_key_v2_group_spis(sa,
                                                last_proto, proto, 1)))
                                                /*
                                                 * XXX Tear down this
                                                 * exchange.
                                                 */
                                                return;
                                        last_proto = proto;
                                }

                                if (sockaddr2text(isa->src_net, &addr1, 0))
                                        addr1 = 0;
                                if (sockaddr2text(isa->src_mask, &mask1, 0))
                                        mask1 = 0;
                                if (sockaddr2text(isa->dst_net, &addr2, 0))
                                        addr2 = 0;
                                if (sockaddr2text(isa->dst_mask, &mask2, 0))
                                        mask2 = 0;

                                LOG_DBG((LOG_EXCHANGE, 50,
                                    "ipsec_finalize_exchange: src %s %s "
                                    "dst %s %s tproto %u sport %u dport %u",
                                    addr1 ? addr1 : "<??\?>",
                                    mask1 ?  mask1 : "<??\?>",
                                    addr2 ? addr2 : "<??\?>",
                                    mask2 ? mask2 : "<??\?>",
                                    isa->tproto, ntohs(isa->sport),
                                    ntohs(isa->dport)));

                                free(addr1);
                                free(mask1);
                                free(addr2);
                                free(mask2);

                                /*
                                 * If this is not an SA acquired by the
                                 * kernel, it needs to have a SPD entry
                                 * (a.k.a. flow) set up.
                                 */
                                if (!(sa->flags & SA_FLAG_ONDEMAND ||
                                    sa->flags & SA_FLAG_IFACE ||
                                    conf_get_str("General", "Acquire-Only") ||
                                    acquire_only) &&
                                    pf_key_v2_enable_sa(sa, isakmp_sa))
                                        /* XXX Tear down this exchange.  */
                                        return;

                                /*
                                 * Mark elder SAs with the same flow
                                 * information as replaced.
                                 */
                                while ((old_sa = sa_find(ipsec_sa_check_flow,
                                    sa)) != 0)
                                        sa_mark_replaced(old_sa);
                        }
                        break;
                }
        }
}

/* Set the client addresses in ISA from SRC_ID and DST_ID.  */
static int
ipsec_set_network(u_int8_t *src_id, u_int8_t *dst_id, struct sa *sa)
{
        void               *src_net, *dst_net;
        void               *src_mask = NULL, *dst_mask = NULL;
        struct sockaddr    *addr;
        struct proto       *proto;
        struct ipsec_proto *iproto;
        struct ipsec_sa    *isa = sa->data;
        int                 src_af, dst_af;
        int                 id;
        char               *name, *nat = NULL;
        u_int8_t           *nat_id = NULL;
        size_t              nat_sz;

        if ((name = connection_passive_lookup_by_ids(src_id, dst_id)))
                nat = conf_get_str(name, "NAT-ID");

        if (nat) {
                if ((nat_id = ipsec_build_id(nat, &nat_sz))) {
                        LOG_DBG((LOG_EXCHANGE, 50, "ipsec_set_network: SRC-NAT:"
                            " src: %s -> %s", name, nat));
                        src_id = nat_id;
                } else
                        log_print("ipsec_set_network: ipsec_build_id"
                            " failed for NAT-ID: %s", nat);
        }

        if (((proto = TAILQ_FIRST(&sa->protos)) != NULL) &&
            ((iproto = proto->data) != NULL) && 
            (iproto->encap_mode == IPSEC_ENCAP_UDP_ENCAP_TRANSPORT ||
            iproto->encap_mode == IPSEC_ENCAP_UDP_ENCAP_TRANSPORT_DRAFT)) {
                /*
                 * For NAT-T with transport mode, we need to use the ISAKMP's
                 * SA addresses for the flow.
                 */
                sa->transport->vtbl->get_src(sa->transport, &addr);
                src_af = addr->sa_family;
                src_net = sockaddr_addrdata(addr);

                sa->transport->vtbl->get_dst(sa->transport, &addr);
                dst_af = addr->sa_family;
                dst_net = sockaddr_addrdata(addr);
        } else {
                id = GET_ISAKMP_ID_TYPE(src_id);
                src_net = src_id + ISAKMP_ID_DATA_OFF;
                switch (id) {
                case IPSEC_ID_IPV4_ADDR_SUBNET:
                        src_mask = (u_int8_t *)src_net + sizeof(struct in_addr);
                        /* FALLTHROUGH */
                case IPSEC_ID_IPV4_ADDR:
                        src_af = AF_INET;
                        break;

                case IPSEC_ID_IPV6_ADDR_SUBNET:
                        src_mask = (u_int8_t *)src_net +
                            sizeof(struct in6_addr);
                        /* FALLTHROUGH */
                case IPSEC_ID_IPV6_ADDR:
                        src_af = AF_INET6;
                        break;

                default:
                        log_print(
                            "ipsec_set_network: ID type %d (%s) not supported",
                            id, constant_name(ipsec_id_cst, id));
                        return -1;
                }

                id = GET_ISAKMP_ID_TYPE(dst_id);
                dst_net = dst_id + ISAKMP_ID_DATA_OFF;
                switch (id) {
                case IPSEC_ID_IPV4_ADDR_SUBNET:
                        dst_mask = (u_int8_t *)dst_net + sizeof(struct in_addr);
                        /* FALLTHROUGH */
                case IPSEC_ID_IPV4_ADDR:
                        dst_af = AF_INET;
                        break;

                case IPSEC_ID_IPV6_ADDR_SUBNET:
                        dst_mask = (u_int8_t *)dst_net +
                            sizeof(struct in6_addr);
                        /* FALLTHROUGH */
                case IPSEC_ID_IPV6_ADDR:
                        dst_af = AF_INET6;
                        break;

                default:
                        log_print(
                            "ipsec_set_network: ID type %d (%s) not supported",
                            id, constant_name(ipsec_id_cst, id));
                        return -1;
                }
        }

        /* Set source address/mask.  */
        switch (src_af) {
        case AF_INET:
                isa->src_net = calloc(1, sizeof(struct sockaddr_in));
                if (!isa->src_net)
                        goto memfail;
                isa->src_net->sa_family = AF_INET;
                isa->src_net->sa_len = sizeof(struct sockaddr_in);

                isa->src_mask = calloc(1, sizeof(struct sockaddr_in));
                if (!isa->src_mask)
                        goto memfail;
                isa->src_mask->sa_family = AF_INET;
                isa->src_mask->sa_len = sizeof(struct sockaddr_in);
                break;

        case AF_INET6:
                isa->src_net = calloc(1, sizeof(struct sockaddr_in6));
                if (!isa->src_net)
                        goto memfail;
                isa->src_net->sa_family = AF_INET6;
                isa->src_net->sa_len = sizeof(struct sockaddr_in6);

                isa->src_mask = calloc(1, sizeof(struct sockaddr_in6));
                if (!isa->src_mask)
                        goto memfail;
                isa->src_mask->sa_family = AF_INET6;
                isa->src_mask->sa_len = sizeof(struct sockaddr_in6);
                break;
        }

        /* Net */
        memcpy(sockaddr_addrdata(isa->src_net), src_net,
            sockaddr_addrlen(isa->src_net));

        /* Mask */
        if (src_mask == NULL)
                memset(sockaddr_addrdata(isa->src_mask), 0xff,
                    sockaddr_addrlen(isa->src_mask));
        else
                memcpy(sockaddr_addrdata(isa->src_mask), src_mask,
                    sockaddr_addrlen(isa->src_mask));

        memcpy(&isa->sport,
            src_id + ISAKMP_ID_DOI_DATA_OFF + IPSEC_ID_PORT_OFF,
            IPSEC_ID_PORT_LEN);

        free(nat_id);

        /* Set destination address.  */
        switch (dst_af) {
        case AF_INET:
                isa->dst_net = calloc(1, sizeof(struct sockaddr_in));
                if (!isa->dst_net)
                        goto memfail;
                isa->dst_net->sa_family = AF_INET;
                isa->dst_net->sa_len = sizeof(struct sockaddr_in);

                isa->dst_mask = calloc(1, sizeof(struct sockaddr_in));
                if (!isa->dst_mask)
                        goto memfail;
                isa->dst_mask->sa_family = AF_INET;
                isa->dst_mask->sa_len = sizeof(struct sockaddr_in);
                break;

        case AF_INET6:
                isa->dst_net = calloc(1, sizeof(struct sockaddr_in6));
                if (!isa->dst_net)
                        goto memfail;
                isa->dst_net->sa_family = AF_INET6;
                isa->dst_net->sa_len = sizeof(struct sockaddr_in6);

                isa->dst_mask = calloc(1, sizeof(struct sockaddr_in6));
                if (!isa->dst_mask)
                        goto memfail;
                isa->dst_mask->sa_family = AF_INET6;
                isa->dst_mask->sa_len = sizeof(struct sockaddr_in6);
                break;
        }

        /* Net */
        memcpy(sockaddr_addrdata(isa->dst_net), dst_net,
            sockaddr_addrlen(isa->dst_net));

        /* Mask */
        if (dst_mask == NULL)
                memset(sockaddr_addrdata(isa->dst_mask), 0xff,
                    sockaddr_addrlen(isa->dst_mask));
        else
                memcpy(sockaddr_addrdata(isa->dst_mask), dst_mask,
                    sockaddr_addrlen(isa->dst_mask));

        memcpy(&isa->tproto, dst_id + ISAKMP_ID_DOI_DATA_OFF +
            IPSEC_ID_PROTO_OFF, IPSEC_ID_PROTO_LEN);
        memcpy(&isa->dport,
            dst_id + ISAKMP_ID_DOI_DATA_OFF + IPSEC_ID_PORT_OFF,
            IPSEC_ID_PORT_LEN);
        return 0;

memfail:
        log_error("ipsec_set_network: calloc () failed");
        return -1;
}

/* Free the DOI-specific exchange data pointed to by VIE.  */
static void
ipsec_free_exchange_data(void *vie)
{
        struct ipsec_exch *ie = vie;
        struct isakmp_cfg_attr *attr;

        free(ie->sa_i_b);
        free(ie->id_ci);
        free(ie->id_cr);
        free(ie->g_xi);
        free(ie->g_xr);
        free(ie->g_xy);
        free(ie->skeyid);
        free(ie->skeyid_d);
        free(ie->skeyid_a);
        free(ie->skeyid_e);
        free(ie->hash_i);
        free(ie->hash_r);
        if (ie->group)
                group_free(ie->group);
        for (attr = LIST_FIRST(&ie->attrs); attr;
            attr = LIST_FIRST(&ie->attrs)) {
                LIST_REMOVE(attr, link);
                if (attr->length)
                        free(attr->value);
                free(attr);
        }
}

/* Free the DOI-specific SA data pointed to by VISA.  */
static void
ipsec_free_sa_data(void *visa)
{
        struct ipsec_sa *isa = visa;

        free(isa->src_net);
        free(isa->src_mask);
        free(isa->dst_net);
        free(isa->dst_mask);
        free(isa->skeyid_a);
        free(isa->skeyid_d);
}

/* Free the DOI-specific protocol data of an SA pointed to by VIPROTO.  */
static void
ipsec_free_proto_data(void *viproto)
{
        struct ipsec_proto *iproto = viproto;
        int             i;

        for (i = 0; i < 2; i++)
                free(iproto->keymat[i]);
}

/* Return exchange script based on TYPE.  */
static int16_t *
ipsec_exchange_script(u_int8_t type)
{
        switch (type) {
        case ISAKMP_EXCH_TRANSACTION:
                return script_transaction;
        case IKE_EXCH_QUICK_MODE:
                return script_quick_mode;
        case IKE_EXCH_NEW_GROUP_MODE:
                return script_new_group_mode;
        }
        return 0;
}

/* Initialize this DOI, requires doi_init to already have been called.  */
void
ipsec_init(void)
{
        doi_register(&ipsec_doi);
}

/* Given a message MSG, return a suitable IV (or rather keystate).  */
static struct keystate *
ipsec_get_keystate(struct message *msg)
{
        struct keystate *ks;
        struct hash    *hash;

        /* If we have already have an IV, use it.  */
        if (msg->exchange && msg->exchange->keystate) {
                ks = malloc(sizeof *ks);
                if (!ks) {
                        log_error("ipsec_get_keystate: malloc (%lu) failed",
                            (unsigned long) sizeof *ks);
                        return 0;
                }
                memcpy(ks, msg->exchange->keystate, sizeof *ks);
                return ks;
        }
        /*
         * For phase 2 when no SA yet is setup we need to hash the IV used by
         * the ISAKMP SA concatenated with the message ID, and use that as an
         * IV for further cryptographic operations.
         */
        if (!msg->isakmp_sa->keystate) {
                log_print("ipsec_get_keystate: no keystate in ISAKMP SA %p",
                    msg->isakmp_sa);
                return 0;
        }
        ks = crypto_clone_keystate(msg->isakmp_sa->keystate);
        if (!ks)
                return 0;

        hash = hash_get(((struct ipsec_sa *)msg->isakmp_sa->data)->hash);
        hash->Init(hash->ctx);
        LOG_DBG_BUF((LOG_CRYPTO, 80, "ipsec_get_keystate: final phase 1 IV",
            ks->riv, ks->xf->blocksize));
        hash->Update(hash->ctx, ks->riv, ks->xf->blocksize);
        LOG_DBG_BUF((LOG_CRYPTO, 80, "ipsec_get_keystate: message ID",
            ((u_int8_t *) msg->iov[0].iov_base) + ISAKMP_HDR_MESSAGE_ID_OFF,
            ISAKMP_HDR_MESSAGE_ID_LEN));
        hash->Update(hash->ctx, ((u_int8_t *) msg->iov[0].iov_base) +
            ISAKMP_HDR_MESSAGE_ID_OFF, ISAKMP_HDR_MESSAGE_ID_LEN);
        hash->Final(hash->digest, hash->ctx);
        crypto_init_iv(ks, hash->digest, ks->xf->blocksize);
        LOG_DBG_BUF((LOG_CRYPTO, 80, "ipsec_get_keystate: phase 2 IV",
            hash->digest, ks->xf->blocksize));
        return ks;
}

static void
ipsec_setup_situation(u_int8_t *buf)
{
        SET_IPSEC_SIT_SIT(buf + ISAKMP_SA_SIT_OFF, IPSEC_SIT_IDENTITY_ONLY);
}

static size_t
ipsec_situation_size(void)
{
        return IPSEC_SIT_SIT_LEN;
}

static u_int8_t
ipsec_spi_size(u_int8_t proto)
{
        return IPSEC_SPI_SIZE;
}

static int
ipsec_validate_attribute(u_int16_t type, u_int8_t * value, u_int16_t len,
    void *vmsg)
{
        struct message *msg = vmsg;

        if (msg->exchange->phase == 1 &&
            (type < IKE_ATTR_ENCRYPTION_ALGORITHM || type > IKE_ATTR_GROUP_ORDER))
                return -1;
        if (msg->exchange->phase == 2 &&
            (type < IPSEC_ATTR_SA_LIFE_TYPE || type > IPSEC_ATTR_ECN_TUNNEL))
                return -1;
        return 0;
}

static int
ipsec_validate_exchange(u_int8_t exch)
{
        return exch != IKE_EXCH_QUICK_MODE && exch != IKE_EXCH_NEW_GROUP_MODE;
}

static int
ipsec_validate_id_information(u_int8_t type, u_int8_t *extra, u_int8_t *buf,
    size_t sz, struct exchange *exchange)
{
        u_int8_t        proto = GET_IPSEC_ID_PROTO(extra);
        u_int16_t       port = GET_IPSEC_ID_PORT(extra);

        LOG_DBG((LOG_MESSAGE, 40,
            "ipsec_validate_id_information: proto %d port %d type %d",
            proto, port, type));
        if (type < IPSEC_ID_IPV4_ADDR || type > IPSEC_ID_KEY_ID)
                return -1;

        switch (type) {
        case IPSEC_ID_IPV4_ADDR:
                LOG_DBG_BUF((LOG_MESSAGE, 40,
                    "ipsec_validate_id_information: IPv4", buf,
                    sizeof(struct in_addr)));
                break;

        case IPSEC_ID_IPV6_ADDR:
                LOG_DBG_BUF((LOG_MESSAGE, 40,
                    "ipsec_validate_id_information: IPv6", buf,
                    sizeof(struct in6_addr)));
                break;

        case IPSEC_ID_IPV4_ADDR_SUBNET:
                LOG_DBG_BUF((LOG_MESSAGE, 40,
                    "ipsec_validate_id_information: IPv4 network/netmask",
                    buf, 2 * sizeof(struct in_addr)));
                break;

        case IPSEC_ID_IPV6_ADDR_SUBNET:
                LOG_DBG_BUF((LOG_MESSAGE, 40,
                    "ipsec_validate_id_information: IPv6 network/netmask",
                    buf, 2 * sizeof(struct in6_addr)));
                break;

        default:
                break;
        }

        if (exchange->phase == 1 &&
            (proto != IPPROTO_UDP || port != UDP_DEFAULT_PORT) &&
            (proto != 0 || port != 0)) {
                /*
                 * XXX SSH's ISAKMP tester fails this test (proto 17 - port
                 * 0).
                 */
#ifdef notyet
                return -1;
#else
                log_print("ipsec_validate_id_information: dubious ID "
                    "information accepted");
#endif
        }
        /* XXX More checks?  */

        return 0;
}

static int
ipsec_validate_key_information(u_int8_t *buf, size_t sz)
{
        /* XXX Not implemented yet.  */
        return 0;
}

static int
ipsec_validate_notification(u_int16_t type)
{
        return type < IPSEC_NOTIFY_RESPONDER_LIFETIME ||
            type > IPSEC_NOTIFY_INITIAL_CONTACT ? -1 : 0;
}

static int
ipsec_validate_proto(u_int8_t proto)
{
        return proto < IPSEC_PROTO_IPSEC_AH ||
            proto > IPSEC_PROTO_IPCOMP ? -1 : 0;
}

static int
ipsec_validate_situation(u_int8_t *buf, size_t *sz, size_t len)
{
        if (len < IPSEC_SIT_SIT_OFF + IPSEC_SIT_SIT_LEN) {
                log_print("ipsec_validate_situation: payload too short: %u",
                    (unsigned int) len);
                return -1;
        }
        /* Currently only "identity only" situations are supported.  */
        if (GET_IPSEC_SIT_SIT(buf) != IPSEC_SIT_IDENTITY_ONLY)
                return 1;

        *sz = IPSEC_SIT_SIT_LEN;

        return 0;
}

static int
ipsec_validate_transform_id(u_int8_t proto, u_int8_t transform_id)
{
        switch (proto) {
        /*
         * As no unexpected protocols can occur, we just tie the
         * default case to the first case, in order to silence a GCC
         * warning.
         */
        default:
        case ISAKMP_PROTO_ISAKMP:
                return transform_id != IPSEC_TRANSFORM_KEY_IKE;
        case IPSEC_PROTO_IPSEC_AH:
                return transform_id < IPSEC_AH_MD5 ||
                    transform_id > IPSEC_AH_RIPEMD ? -1 : 0;
        case IPSEC_PROTO_IPSEC_ESP:
                return transform_id < IPSEC_ESP_DES_IV64 ||
                    (transform_id > IPSEC_ESP_AES_GMAC &&
                    transform_id < IPSEC_ESP_AES_MARS) ||
                    transform_id > IPSEC_ESP_AES_TWOFISH ? -1 : 0;
        case IPSEC_PROTO_IPCOMP:
                return transform_id < IPSEC_IPCOMP_OUI ||
                    transform_id > IPSEC_IPCOMP_DEFLATE ? -1 : 0;
        }
}

static int
ipsec_initiator(struct message *msg)
{
        struct exchange *exchange = msg->exchange;
        int             (**script)(struct message *) = 0;

        /* Check that the SA is coherent with the IKE rules.  */
        if (exchange->type != ISAKMP_EXCH_TRANSACTION &&
            ((exchange->phase == 1 && exchange->type != ISAKMP_EXCH_ID_PROT &&
            exchange->type != ISAKMP_EXCH_AGGRESSIVE &&
            exchange->type != ISAKMP_EXCH_INFO) ||
            (exchange->phase == 2 && exchange->type != IKE_EXCH_QUICK_MODE &&
            exchange->type != ISAKMP_EXCH_INFO))) {
                log_print("ipsec_initiator: unsupported exchange type %d "
                    "in phase %d", exchange->type, exchange->phase);
                return -1;
        }
        switch (exchange->type) {
        case ISAKMP_EXCH_ID_PROT:
                script = ike_main_mode_initiator;
                break;
        case ISAKMP_EXCH_AGGRESSIVE:
                script = ike_aggressive_initiator;
                break;
        case ISAKMP_EXCH_TRANSACTION:
                script = isakmp_cfg_initiator;
                break;
        case ISAKMP_EXCH_INFO:
                return message_send_info(msg);
        case IKE_EXCH_QUICK_MODE:
                script = ike_quick_mode_initiator;
                break;
        default:
                log_print("ipsec_initiator: unsupported exchange type %d",
                          exchange->type);
                return -1;
        }

        /* Run the script code for this step.  */
        if (script)
                return script[exchange->step] (msg);

        return 0;
}

/*
 * delete all SA's from addr with the associated proto and SPI's
 *
 * spis[] is an array of SPIs of size 16-octet for proto ISAKMP
 * or 4-octet otherwise.
 */
static void
ipsec_delete_spi_list(struct sockaddr *addr, u_int8_t proto, u_int8_t *spis,
    int nspis, char *type)
{
        struct sa       *sa;
        char            *peer;
        char             ids[1024];
        int              i;

        for (i = 0; i < nspis; i++) {
                if (proto == ISAKMP_PROTO_ISAKMP) {
                        u_int8_t *spi = spis + i * ISAKMP_HDR_COOKIES_LEN;

                        /*
                         * This really shouldn't happen in IPSEC DOI
                         * code, but Cisco VPN 3000 sends ISAKMP DELETE's
                         * this way.
                         */
                        sa = sa_lookup_isakmp_sa(addr, spi);
                } else {
                        u_int32_t spi = ((u_int32_t *)spis)[i];

                        sa = ipsec_sa_lookup(addr, spi, proto);
                }

                if (sa == NULL) {
                        LOG_DBG((LOG_SA, 30, "ipsec_delete_spi_list: could "
                            "not locate SA (SPI %08x, proto %u)",
                            ((u_int32_t *)spis)[i], proto));
                        continue;
                }

                strlcpy(ids,
                    sa->doi->decode_ids("initiator id: %s, responder id: %s",
                    sa->id_i, sa->id_i_len, sa->id_r, sa->id_r_len, 0),
                    sizeof ids);
                if (sockaddr2text(addr, &peer, 0))
                        peer = NULL;

                /* only log deletion of SAs which are not soft expired yet */
                if (sa->soft_death != NULL)
                        log_verbose("isakmpd: Peer %s made us delete live SA "
                            "%s for proto %d, %s", peer ? peer : "<unknown>",
                            sa->name ? sa->name : "<unnamed>", proto, ids);

                LOG_DBG((LOG_SA, 30, "ipsec_delete_spi_list: "
                    "%s made us delete SA %p (%d references) for proto %d (%s)",
                    type, sa, sa->refcnt, proto, ids));
                free(peer);

                /* Delete the SA and search for the next */
                sa_free(sa);
        }
}

static int
ipsec_responder(struct message *msg)
{
        struct exchange *exchange = msg->exchange;
        int             (**script)(struct message *) = 0;
        struct payload *p;
        u_int16_t       type;

        /* Check that a new exchange is coherent with the IKE rules.  */
        if (exchange->step == 0 && exchange->type != ISAKMP_EXCH_TRANSACTION &&
            ((exchange->phase == 1 && exchange->type != ISAKMP_EXCH_ID_PROT &&
            exchange->type != ISAKMP_EXCH_AGGRESSIVE &&
            exchange->type != ISAKMP_EXCH_INFO) ||
            (exchange->phase == 2 && exchange->type != IKE_EXCH_QUICK_MODE &&
            exchange->type != ISAKMP_EXCH_INFO))) {
                message_drop(msg, ISAKMP_NOTIFY_UNSUPPORTED_EXCHANGE_TYPE,
                    0, 1, 0);
                return -1;
        }
        LOG_DBG((LOG_MISC, 30, "ipsec_responder: phase %d exchange %d step %d",
            exchange->phase, exchange->type, exchange->step));
        switch (exchange->type) {
        case ISAKMP_EXCH_ID_PROT:
                script = ike_main_mode_responder;
                break;
        case ISAKMP_EXCH_AGGRESSIVE:
                script = ike_aggressive_responder;
                break;
        case ISAKMP_EXCH_TRANSACTION:
                script = isakmp_cfg_responder;
                break;
        case ISAKMP_EXCH_INFO:
                TAILQ_FOREACH(p, &msg->payload[ISAKMP_PAYLOAD_NOTIFY], link) {
                        type = GET_ISAKMP_NOTIFY_MSG_TYPE(p->p);
                        LOG_DBG((LOG_EXCHANGE, 10,
                            "ipsec_responder: got NOTIFY of type %s",
                            constant_name(isakmp_notify_cst, type)));

                        switch (type) {
                        case IPSEC_NOTIFY_INITIAL_CONTACT:
                                /* Handled by leftover logic. */
                                break;

                        case ISAKMP_NOTIFY_STATUS_DPD_R_U_THERE:
                        case ISAKMP_NOTIFY_STATUS_DPD_R_U_THERE_ACK:
                                dpd_handle_notify(msg, p);
                                break;

                        default:
                                p->flags |= PL_MARK;
                                break;
                        }
                }

                /*
                 * If any DELETEs are in here, let the logic of leftover
                 * payloads deal with them.
                 */
                return 0;

        case IKE_EXCH_QUICK_MODE:
                script = ike_quick_mode_responder;
                break;

        default:
                message_drop(msg, ISAKMP_NOTIFY_UNSUPPORTED_EXCHANGE_TYPE,
                    0, 1, 0);
                return -1;
        }

        /* Run the script code for this step.  */
        if (script)
                return script[exchange->step] (msg);

        /*
         * XXX So far we don't accept any proposals for exchanges we don't
         * support.
         */
        if (payload_first(msg, ISAKMP_PAYLOAD_SA)) {
                message_drop(msg, ISAKMP_NOTIFY_NO_PROPOSAL_CHOSEN, 0, 1, 0);
                return -1;
        }
        return 0;
}

static enum hashes
from_ike_hash(u_int16_t hash)
{
        switch (hash) {
                case IKE_HASH_MD5:
                return HASH_MD5;
        case IKE_HASH_SHA:
                return HASH_SHA1;
        case IKE_HASH_SHA2_256:
                return HASH_SHA2_256;
        case IKE_HASH_SHA2_384:
                return HASH_SHA2_384;
        case IKE_HASH_SHA2_512:
                return HASH_SHA2_512;
        }
        return -1;
}

static enum transform
from_ike_crypto(u_int16_t crypto)
{
        /* Coincidentally this is the null operation :-)  */
        return crypto;
}

/*
 * Find out whether the attribute of type TYPE with a LEN length value
 * pointed to by VALUE is incompatible with what we can handle.
 * VMSG is a pointer to the current message.
 */
int
ipsec_is_attribute_incompatible(u_int16_t type, u_int8_t *value, u_int16_t len,
    void *vmsg)
{
        struct message *msg = vmsg;
        u_int16_t dv = decode_16(value);

        if (msg->exchange->phase == 1) {
                switch (type) {
                case IKE_ATTR_ENCRYPTION_ALGORITHM:
                        return !crypto_get(from_ike_crypto(dv));
                case IKE_ATTR_HASH_ALGORITHM:
                        return !hash_get(from_ike_hash(dv));
                case IKE_ATTR_AUTHENTICATION_METHOD:
                        return !ike_auth_get(dv);
                case IKE_ATTR_GROUP_DESCRIPTION:
                        return (dv < IKE_GROUP_DESC_MODP_768 ||
                            dv > IKE_GROUP_DESC_MODP_1536) &&
                            (dv < IKE_GROUP_DESC_MODP_2048 ||
                            dv > IKE_GROUP_DESC_ECP_521) &&
                            (dv < IKE_GROUP_DESC_ECP_224 ||
                            dv > IKE_GROUP_DESC_BP_512);
                case IKE_ATTR_GROUP_TYPE:
                        return 1;
                case IKE_ATTR_GROUP_PRIME:
                        return 1;
                case IKE_ATTR_GROUP_GENERATOR_1:
                        return 1;
                case IKE_ATTR_GROUP_GENERATOR_2:
                        return 1;
                case IKE_ATTR_GROUP_CURVE_A:
                        return 1;
                case IKE_ATTR_GROUP_CURVE_B:
                        return 1;
                case IKE_ATTR_LIFE_TYPE:
                        return dv < IKE_DURATION_SECONDS ||
                            dv > IKE_DURATION_KILOBYTES;
                case IKE_ATTR_LIFE_DURATION:
                        return len != 2 && len != 4;
                case IKE_ATTR_PRF:
                        return 1;
                case IKE_ATTR_KEY_LENGTH:
                        /*
                         * Our crypto routines only allows key-lengths which
                         * are multiples of an octet.
                         */
                        return dv % 8 != 0;
                case IKE_ATTR_FIELD_SIZE:
                        return 1;
                case IKE_ATTR_GROUP_ORDER:
                        return 1;
                }
        } else {
                switch (type) {
                case IPSEC_ATTR_SA_LIFE_TYPE:
                        return dv < IPSEC_DURATION_SECONDS ||
                            dv > IPSEC_DURATION_KILOBYTES;
                case IPSEC_ATTR_SA_LIFE_DURATION:
                        return len != 2 && len != 4;
                case IPSEC_ATTR_GROUP_DESCRIPTION:
                        return (dv < IKE_GROUP_DESC_MODP_768 ||
                            dv > IKE_GROUP_DESC_MODP_1536) &&
                            (dv < IKE_GROUP_DESC_MODP_2048 ||
                            dv > IKE_GROUP_DESC_ECP_521) &&
                            (dv < IKE_GROUP_DESC_ECP_224 ||
                            dv > IKE_GROUP_DESC_BP_512);
                case IPSEC_ATTR_ENCAPSULATION_MODE:
                        return dv != IPSEC_ENCAP_TUNNEL &&
                            dv != IPSEC_ENCAP_TRANSPORT &&
                            dv != IPSEC_ENCAP_UDP_ENCAP_TUNNEL &&
                            dv != IPSEC_ENCAP_UDP_ENCAP_TRANSPORT &&
                            dv != IPSEC_ENCAP_UDP_ENCAP_TUNNEL_DRAFT &&
                            dv != IPSEC_ENCAP_UDP_ENCAP_TRANSPORT_DRAFT;
                case IPSEC_ATTR_AUTHENTICATION_ALGORITHM:
                        return dv < IPSEC_AUTH_HMAC_MD5 ||
                            dv > IPSEC_AUTH_HMAC_RIPEMD;
                case IPSEC_ATTR_KEY_LENGTH:
                        /*
                         * XXX Blowfish needs '0'. Others appear to disregard
                         * this attr?
                         */
                        return 0;
                case IPSEC_ATTR_KEY_ROUNDS:
                        return 1;
                case IPSEC_ATTR_COMPRESS_DICTIONARY_SIZE:
                        return 1;
                case IPSEC_ATTR_COMPRESS_PRIVATE_ALGORITHM:
                        return 1;
                case IPSEC_ATTR_ECN_TUNNEL:
                        return 1;
                }
        }
        /* XXX Silence gcc.  */
        return 1;
}

/*
 * Log the attribute of TYPE with a LEN length value pointed to by VALUE
 * in human-readable form.  VMSG is a pointer to the current message.
 */
int
ipsec_debug_attribute(u_int16_t type, u_int8_t *value, u_int16_t len,
    void *vmsg)
{
        struct message *msg = vmsg;
        char            val[20];

        /* XXX Transient solution.  */
        if (len == 2)
                snprintf(val, sizeof val, "%d", decode_16(value));
        else if (len == 4)
                snprintf(val, sizeof val, "%d", decode_32(value));
        else
                snprintf(val, sizeof val, "unrepresentable");

        LOG_DBG((LOG_MESSAGE, 50, "Attribute %s value %s",
            constant_name(msg->exchange->phase == 1 ? ike_attr_cst :
            ipsec_attr_cst, type), val));
        return 0;
}

/*
 * Decode the attribute of type TYPE with a LEN length value pointed to by
 * VALUE.  VIDA is a pointer to a context structure where we can find the
 * current message, SA and protocol.
 */
int
ipsec_decode_attribute(u_int16_t type, u_int8_t *value, u_int16_t len,
    void *vida)
{
        struct ipsec_decode_arg *ida = vida;
        struct message *msg = ida->msg;
        struct sa      *sa = ida->sa;
        struct ipsec_sa *isa = sa->data;
        struct proto   *proto = ida->proto;
        struct ipsec_proto *iproto = proto->data;
        struct exchange *exchange = msg->exchange;
        struct ipsec_exch *ie = exchange->data;
        static int      lifetype = 0;

        if (exchange->phase == 1) {
                switch (type) {
                case IKE_ATTR_ENCRYPTION_ALGORITHM:
                        /* XXX Errors possible?  */
                        exchange->crypto = crypto_get(from_ike_crypto(
                            decode_16(value)));
                        break;
                case IKE_ATTR_HASH_ALGORITHM:
                        /* XXX Errors possible?  */
                        ie->hash = hash_get(from_ike_hash(decode_16(value)));
                        break;
                case IKE_ATTR_AUTHENTICATION_METHOD:
                        /* XXX Errors possible?  */
                        ie->ike_auth = ike_auth_get(decode_16(value));
                        break;
                case IKE_ATTR_GROUP_DESCRIPTION:
                        isa->group_desc = decode_16(value);
                        break;
                case IKE_ATTR_GROUP_TYPE:
                        break;
                case IKE_ATTR_GROUP_PRIME:
                        break;
                case IKE_ATTR_GROUP_GENERATOR_1:
                        break;
                case IKE_ATTR_GROUP_GENERATOR_2:
                        break;
                case IKE_ATTR_GROUP_CURVE_A:
                        break;
                case IKE_ATTR_GROUP_CURVE_B:
                        break;
                case IKE_ATTR_LIFE_TYPE:
                        lifetype = decode_16(value);
                        return 0;
                case IKE_ATTR_LIFE_DURATION:
                        switch (lifetype) {
                        case IKE_DURATION_SECONDS:
                                switch (len) {
                                case 2:
                                        sa->seconds = decode_16(value);
                                        break;
                                case 4:
                                        sa->seconds = decode_32(value);
                                        break;
                                default:
                                        log_print("ipsec_decode_attribute: "
                                            "unreasonable lifetime");
                                }
                                break;
                        case IKE_DURATION_KILOBYTES:
                                switch (len) {
                                case 2:
                                        sa->kilobytes = decode_16(value);
                                        break;
                                case 4:
                                        sa->kilobytes = decode_32(value);
                                        break;
                                default:
                                        log_print("ipsec_decode_attribute: "
                                            "unreasonable lifetime");
                                }
                                break;
                        default:
                                log_print("ipsec_decode_attribute: unknown "
                                    "lifetime type");
                        }
                        break;
                case IKE_ATTR_PRF:
                        break;
                case IKE_ATTR_KEY_LENGTH:
                        exchange->key_length = decode_16(value) / 8;
                        break;
                case IKE_ATTR_FIELD_SIZE:
                        break;
                case IKE_ATTR_GROUP_ORDER:
                        break;
                }
        } else {
                switch (type) {
                case IPSEC_ATTR_SA_LIFE_TYPE:
                        lifetype = decode_16(value);
                        return 0;
                case IPSEC_ATTR_SA_LIFE_DURATION:
                        switch (lifetype) {
                        case IPSEC_DURATION_SECONDS:
                                switch (len) {
                                case 2:
                                        sa->seconds = decode_16(value);
                                        break;
                                case 4:
                                        sa->seconds = decode_32(value);
                                        break;
                                default:
                                        log_print("ipsec_decode_attribute: "
                                            "unreasonable lifetime");
                                }
                                break;
                        case IPSEC_DURATION_KILOBYTES:
                                switch (len) {
                                case 2:
                                        sa->kilobytes = decode_16(value);
                                        break;
                                case 4:
                                        sa->kilobytes = decode_32(value);
                                        break;
                                default:
                                        log_print("ipsec_decode_attribute: "
                                            "unreasonable lifetime");
                                }
                                break;
                        default:
                                log_print("ipsec_decode_attribute: unknown "
                                    "lifetime type");
                        }
                        break;
                case IPSEC_ATTR_GROUP_DESCRIPTION:
                        isa->group_desc = decode_16(value);
                        break;
                case IPSEC_ATTR_ENCAPSULATION_MODE:
                        /*
                         * XXX Multiple protocols must have same
                         * encapsulation mode, no?
                         */
                        iproto->encap_mode = decode_16(value);
                        break;
                case IPSEC_ATTR_AUTHENTICATION_ALGORITHM:
                        iproto->auth = decode_16(value);
                        break;
                case IPSEC_ATTR_KEY_LENGTH:
                        iproto->keylen = decode_16(value);
                        break;
                case IPSEC_ATTR_KEY_ROUNDS:
                        iproto->keyrounds = decode_16(value);
                        break;
                case IPSEC_ATTR_COMPRESS_DICTIONARY_SIZE:
                        break;
                case IPSEC_ATTR_COMPRESS_PRIVATE_ALGORITHM:
                        break;
                case IPSEC_ATTR_ECN_TUNNEL:
                        break;
                }
        }
        lifetype = 0;
        return 0;
}

/*
 * Walk over the attributes of the transform payload found in BUF, and
 * fill out the fields of the SA attached to MSG.  Also mark the SA as
 * processed.
 */
void
ipsec_decode_transform(struct message *msg, struct sa *sa, struct proto *proto,
    u_int8_t *buf)
{
        struct ipsec_exch *ie = msg->exchange->data;
        struct ipsec_decode_arg ida;

        LOG_DBG((LOG_MISC, 20, "ipsec_decode_transform: transform %d chosen",
            GET_ISAKMP_TRANSFORM_NO(buf)));

        ida.msg = msg;
        ida.sa = sa;
        ida.proto = proto;

        /* The default IKE lifetime is 8 hours.  */
        if (sa->phase == 1)
                sa->seconds = 28800;

        /* Extract the attributes and stuff them into the SA.  */
        attribute_map(buf + ISAKMP_TRANSFORM_SA_ATTRS_OFF,
            GET_ISAKMP_GEN_LENGTH(buf) - ISAKMP_TRANSFORM_SA_ATTRS_OFF,
            ipsec_decode_attribute, &ida);

        /*
         * If no pseudo-random function was negotiated, it's HMAC.
         * XXX As PRF_HMAC currently is zero, this is a no-op.
         */
        if (!ie->prf_type)
                ie->prf_type = PRF_HMAC;
}

/*
 * Delete the IPsec SA represented by the INCOMING direction in protocol PROTO
 * of the IKE security association SA.
 */
static void
ipsec_delete_spi(struct sa *sa, struct proto *proto, int incoming)
{
        struct sa *new_sa;
        struct ipsec_proto *iproto;

        if (sa->phase == 1)
                return;

        iproto = proto->data;
        /*
         * If the SA is using UDP encap and it replaced other SA,
         * enable the other SA to keep the flow for the other SAs.
         */
        if ((iproto->encap_mode == IPSEC_ENCAP_UDP_ENCAP_TRANSPORT ||
            iproto->encap_mode == IPSEC_ENCAP_UDP_ENCAP_TRANSPORT_DRAFT) &&
            (sa->flags & SA_FLAG_REPLACED) == 0 &&
            (new_sa = sa_find(ipsec_sa_check_flow_any, sa)) != NULL &&
            new_sa->flags & SA_FLAG_REPLACED)
                sa_replace(sa, new_sa);

        /*
         * If the SA was not replaced and was not one acquired through the
         * kernel (ACQUIRE message), remove the flow associated with it.
         * We ignore any errors from the disabling of the flow.
         */
        if (sa->flags & SA_FLAG_READY && !(sa->flags & SA_FLAG_ONDEMAND ||
            sa->flags & SA_FLAG_REPLACED || sa->flags & SA_FLAG_IFACE ||
            acquire_only ||
            conf_get_str("General", "Acquire-Only")))
                pf_key_v2_disable_sa(sa, incoming);

        /* XXX Error handling?  Is it interesting?  */
        pf_key_v2_delete_spi(sa, proto, incoming);
}

/*
 * Store BUF into the g^x entry of the exchange that message MSG belongs to.
 * PEER is non-zero when the value is our peer's, and zero when it is ours.
 */
static int
ipsec_g_x(struct message *msg, int peer, u_int8_t *buf)
{
        struct exchange *exchange = msg->exchange;
        struct ipsec_exch *ie = exchange->data;
        u_int8_t      **g_x;
        int             initiator = exchange->initiator ^ peer;
        char            header[32];

        g_x = initiator ? &ie->g_xi : &ie->g_xr;
        *g_x = malloc(ie->g_x_len);
        if (!*g_x) {
                log_error("ipsec_g_x: malloc (%lu) failed",
                    (unsigned long)ie->g_x_len);
                return -1;
        }
        memcpy(*g_x, buf, ie->g_x_len);
        snprintf(header, sizeof header, "ipsec_g_x: g^x%c",
            initiator ? 'i' : 'r');
        LOG_DBG_BUF((LOG_MISC, 80, header, *g_x, ie->g_x_len));
        return 0;
}

/* Generate our DH value.  */
int
ipsec_gen_g_x(struct message *msg)
{
        struct exchange *exchange = msg->exchange;
        struct ipsec_exch *ie = exchange->data;
        u_int8_t       *buf;

        buf = malloc(ISAKMP_KE_SZ + ie->g_x_len);
        if (!buf) {
                log_error("ipsec_gen_g_x: malloc (%lu) failed",
                    ISAKMP_KE_SZ + (unsigned long)ie->g_x_len);
                return -1;
        }
        if (message_add_payload(msg, ISAKMP_PAYLOAD_KEY_EXCH, buf,
            ISAKMP_KE_SZ + ie->g_x_len, 1)) {
                free(buf);
                return -1;
        }
        if (dh_create_exchange(ie->group, buf + ISAKMP_KE_DATA_OFF)) {
                log_print("ipsec_gen_g_x: dh_create_exchange failed");
                free(buf);
                return -1;
        }
        return ipsec_g_x(msg, 0, buf + ISAKMP_KE_DATA_OFF);
}

/* Save the peer's DH value.  */
int
ipsec_save_g_x(struct message *msg)
{
        struct exchange *exchange = msg->exchange;
        struct ipsec_exch *ie = exchange->data;
        struct payload *kep;

        kep = payload_first(msg, ISAKMP_PAYLOAD_KEY_EXCH);
        kep->flags |= PL_MARK;
        ie->g_x_len = GET_ISAKMP_GEN_LENGTH(kep->p) - ISAKMP_KE_DATA_OFF;

        /* Check that the given length matches the group's expectancy.  */
        if (ie->g_x_len != (size_t) dh_getlen(ie->group)) {
                /* XXX Is this a good notify type?  */
                message_drop(msg, ISAKMP_NOTIFY_PAYLOAD_MALFORMED, 0, 1, 0);
                return -1;
        }
        return ipsec_g_x(msg, 1, kep->p + ISAKMP_KE_DATA_OFF);
}

/*
 * Get a SPI for PROTO and the transport MSG passed over.  Store the
 * size where SZ points.  NB!  A zero return is OK if *SZ is zero.
 */
static u_int8_t *
ipsec_get_spi(size_t *sz, u_int8_t proto, struct message *msg)
{
        struct sockaddr *dst, *src;
        struct transport *transport = msg->transport;

        if (msg->exchange->phase == 1) {
                *sz = 0;
                return 0;
        } else {
                /* We are the destination in the SA we want a SPI for.  */
                transport->vtbl->get_src(transport, &dst);
                /* The peer is the source.  */
                transport->vtbl->get_dst(transport, &src);
                return pf_key_v2_get_spi(sz, proto, src, dst,
                    msg->exchange->seq);
        }
}

/*
 * We have gotten a payload PAYLOAD of type TYPE, which did not get handled
 * by the logic of the exchange MSG takes part in.  Now is the time to deal
 * with such a payload if we know how to, if we don't, return -1, otherwise
 * 0.
 */
int
ipsec_handle_leftover_payload(struct message *msg, u_int8_t type,
    struct payload *payload)
{
        u_int32_t       spisz, nspis;
        struct sockaddr *dst;
        int             reenter = 0;
        u_int8_t       *spis, proto;
        struct sa      *sa;

        switch (type) {
        case ISAKMP_PAYLOAD_DELETE:
                proto = GET_ISAKMP_DELETE_PROTO(payload->p);
                nspis = GET_ISAKMP_DELETE_NSPIS(payload->p);
                spisz = GET_ISAKMP_DELETE_SPI_SZ(payload->p);

                if (nspis == 0) {
                        LOG_DBG((LOG_SA, 60, "ipsec_handle_leftover_payload: "
                            "message specified zero SPIs, ignoring"));
                        return -1;
                }
                /* verify proper SPI size */
                if ((proto == ISAKMP_PROTO_ISAKMP &&
                    spisz != ISAKMP_HDR_COOKIES_LEN) ||
                    (proto != ISAKMP_PROTO_ISAKMP && spisz != sizeof(u_int32_t))) {
                        log_print("ipsec_handle_leftover_payload: invalid SPI "
                            "size %d for proto %d in DELETE payload",
                            spisz, proto);
                        return -1;
                }
                spis = calloc(nspis, spisz);
                if (!spis) {
                        log_error("ipsec_handle_leftover_payload: malloc "
                            "(%d) failed", nspis * spisz);
                        return -1;
                }
                /* extract SPI and get dst address */
                memcpy(spis, payload->p + ISAKMP_DELETE_SPI_OFF, nspis * spisz);
                msg->transport->vtbl->get_dst(msg->transport, &dst);

                ipsec_delete_spi_list(dst, proto, spis, nspis, "DELETE");

                free(spis);
                payload->flags |= PL_MARK;
                return 0;

        case ISAKMP_PAYLOAD_NOTIFY:
                switch (GET_ISAKMP_NOTIFY_MSG_TYPE(payload->p)) {
                case IPSEC_NOTIFY_INITIAL_CONTACT:
                        /*
                         * Permit INITIAL-CONTACT if
                         *   - this is not an AGGRESSIVE mode exchange
                         *   - it is protected by an ISAKMP SA
                         *
                         * XXX Instead of the first condition above, we could
                         * XXX permit this only for phase 2. In the last
                         * XXX packet of main-mode, this payload, while
                         * XXX encrypted, is not part of the hash digest.  As
                         * XXX we currently send our own INITIAL-CONTACTs at
                         * XXX this point, this too would need to be changed.
                         */
                        if (msg->exchange->type == ISAKMP_EXCH_AGGRESSIVE) {
                                log_print("ipsec_handle_leftover_payload: got "
                                    "INITIAL-CONTACT in AGGRESSIVE mode");
                                return -1;
                        }
                        if ((msg->exchange->flags & EXCHANGE_FLAG_ENCRYPT)
                            == 0) {
                                log_print("ipsec_handle_leftover_payload: got "
                                    "INITIAL-CONTACT without ISAKMP SA");
                                return -1;
                        }

                        if ((msg->flags & MSG_AUTHENTICATED) == 0) {
                                log_print("ipsec_handle_leftover_payload: "
                                    "got unauthenticated INITIAL-CONTACT");
                                return -1;
                        }
                        /*
                         * Find out who is sending this and then delete every
                         * SA that is ready.  Exchanges will timeout
                         * themselves and then the non-ready SAs will
                         * disappear too.
                         */
                        msg->transport->vtbl->get_dst(msg->transport, &dst);
                        while ((sa = sa_lookup_by_peer(dst, SA_LEN(dst), 0)) != 0) {
                                /*
                                 * Don't delete the current SA -- we received
                                 * the notification over it, so it's obviously
                                 * still active. We temporarily need to remove
                                 * the SA from the list to avoid an endless
                                 * loop, but keep a reference so it won't
                                 * disappear meanwhile.
                                 */
                                if (sa == msg->isakmp_sa) {
                                        sa_reference(sa);
                                        sa_remove(sa);
                                        reenter = 1;
                                        continue;
                                }
                                LOG_DBG((LOG_SA, 30,
                                    "ipsec_handle_leftover_payload: "
                                    "INITIAL-CONTACT made us delete SA %p",
                                    sa));
                                sa_delete(sa, 0);
                        }

                        if (reenter) {
                                sa_enter(msg->isakmp_sa);
                                sa_release(msg->isakmp_sa);
                        }
                        payload->flags |= PL_MARK;
                        return 0;
                }
        }
        return -1;
}

/* Return the encryption keylength in octets of the ESP protocol PROTO.  */
int
ipsec_esp_enckeylength(struct proto *proto)
{
        struct ipsec_proto *iproto = proto->data;

        /* Compute the keylength to use.  */
        switch (proto->id) {
        case IPSEC_ESP_3DES:
                return 24;
        case IPSEC_ESP_CAST:
                if (!iproto->keylen)
                        return 16;
                return iproto->keylen / 8;
        case IPSEC_ESP_AES_CTR:
        case IPSEC_ESP_AES_GCM_16:
        case IPSEC_ESP_AES_GMAC:
                if (!iproto->keylen)
                        return 20;
                return iproto->keylen / 8 + 4;
        case IPSEC_ESP_AES:
                if (!iproto->keylen)
                        return 16;
                /* FALLTHROUGH */
        default:
                return iproto->keylen / 8;
        }
}

/* Return the authentication keylength in octets of the ESP protocol PROTO.  */
int
ipsec_esp_authkeylength(struct proto *proto)
{
        struct ipsec_proto *iproto = proto->data;

        switch (iproto->auth) {
        case IPSEC_AUTH_HMAC_MD5:
                return 16;
        case IPSEC_AUTH_HMAC_SHA:
        case IPSEC_AUTH_HMAC_RIPEMD:
                return 20;
        case IPSEC_AUTH_HMAC_SHA2_256:
                return 32;
        case IPSEC_AUTH_HMAC_SHA2_384:
                return 48;
        case IPSEC_AUTH_HMAC_SHA2_512:
                return 64;
        default:
                return 0;
        }
}

/* Return the authentication keylength in octets of the AH protocol PROTO.  */
int
ipsec_ah_keylength(struct proto *proto)
{
        switch (proto->id) {
                case IPSEC_AH_MD5:
                return 16;
        case IPSEC_AH_SHA:
        case IPSEC_AH_RIPEMD:
                return 20;
        case IPSEC_AH_SHA2_256:
                return 32;
        case IPSEC_AH_SHA2_384:
                return 48;
        case IPSEC_AH_SHA2_512:
                return 64;
        default:
                return -1;
        }
}

/* Return the total keymaterial length of the protocol PROTO.  */
int
ipsec_keymat_length(struct proto *proto)
{
        switch (proto->proto) {
                case IPSEC_PROTO_IPSEC_ESP:
                return ipsec_esp_enckeylength(proto)
                    + ipsec_esp_authkeylength(proto);
        case IPSEC_PROTO_IPSEC_AH:
                return ipsec_ah_keylength(proto);
        default:
                return -1;
        }
}

/* Helper function for ipsec_get_id().  */
static int
ipsec_get_proto_port(char *section, u_int8_t *tproto, u_int16_t *port)
{
        struct protoent *pe = NULL;
        struct servent  *se;
        char    *pstr;

        pstr = conf_get_str(section, "Protocol");
        if (!pstr) {
                *tproto = 0;
                return 0;
        }
        *tproto = (u_int8_t)atoi(pstr);
        if (!*tproto) {
                pe = getprotobyname(pstr);
                if (pe)
                        *tproto = pe->p_proto;
        }
        if (!*tproto) {
                log_print("ipsec_get_proto_port: protocol \"%s\" unknown",
                    pstr);
                return -1;
        }

        pstr = conf_get_str(section, "Port");
        if (!pstr)
                return 0;
        *port = (u_int16_t)atoi(pstr);
        if (!*port) {
                se = getservbyname(pstr,
                    pe ? pe->p_name : (pstr ? pstr : NULL));
                if (se)
                        *port = ntohs(se->s_port);
        }
        if (!*port) {
                log_print("ipsec_get_proto_port: port \"%s\" unknown",
                    pstr);
                return -1;
        }
        return 0;
}

/*
 * Out of a named section SECTION in the configuration file find out
 * the network address and mask as well as the ID type.  Put the info
 * in the areas pointed to by ADDR, MASK, TPROTO, PORT, and ID respectively.
 * Return 0 on success and -1 on failure.
 */
int
ipsec_get_id(char *section, int *id, struct sockaddr **addr,
    struct sockaddr **mask, u_int8_t *tproto, u_int16_t *port)
{
        char    *type, *address, *netmask;
        sa_family_t     af = 0;

        type = conf_get_str(section, "ID-type");
        if (!type) {
                log_print("ipsec_get_id: section %s has no \"ID-type\" tag",
                    section);
                return -1;
        }
        *id = constant_value(ipsec_id_cst, type);
        switch (*id) {
        case IPSEC_ID_IPV4_ADDR:
        case IPSEC_ID_IPV4_ADDR_SUBNET:
                af = AF_INET;
                break;
        case IPSEC_ID_IPV6_ADDR:
        case IPSEC_ID_IPV6_ADDR_SUBNET:
                af = AF_INET6;
                break;
        }
        switch (*id) {
        case IPSEC_ID_IPV4_ADDR:
        case IPSEC_ID_IPV6_ADDR: {
                int ret;

                address = conf_get_str(section, "Address");
                if (!address) {
                        log_print("ipsec_get_id: section %s has no "
                            "\"Address\" tag", section);
                        return -1;
                }
                if (text2sockaddr(address, NULL, addr, af, 0)) {
                        log_print("ipsec_get_id: invalid address %s in "
                            "section %s", address, section);
                        return -1;
                }
                ret = ipsec_get_proto_port(section, tproto, port);
                if (ret < 0)
                        free(*addr);

                return ret;
        }

#ifdef notyet
        case IPSEC_ID_FQDN:
                return -1;

        case IPSEC_ID_USER_FQDN:
                return -1;
#endif

        case IPSEC_ID_IPV4_ADDR_SUBNET:
        case IPSEC_ID_IPV6_ADDR_SUBNET: {
                int ret;

                address = conf_get_str(section, "Network");
                if (!address) {
                        log_print("ipsec_get_id: section %s has no "
                            "\"Network\" tag", section);
                        return -1;
                }
                if (text2sockaddr(address, NULL, addr, af, 0)) {
                        log_print("ipsec_get_id: invalid section %s "
                            "network %s", section, address);
                        return -1;
                }
                netmask = conf_get_str(section, "Netmask");
                if (!netmask) {
                        log_print("ipsec_get_id: section %s has no "
                            "\"Netmask\" tag", section);
                        free(*addr);
                        return -1;
                }
                if (text2sockaddr(netmask, NULL, mask, af, 1)) {
                        log_print("ipsec_get_id: invalid section %s "
                            "network %s", section, netmask);
                        free(*addr);
                        return -1;
                }
                ret = ipsec_get_proto_port(section, tproto, port);
                if (ret < 0) {
                        free(*mask);
                        free(*addr);
                }
                return ret;
        }

#ifdef notyet
        case IPSEC_ID_IPV4_RANGE:
                return -1;

        case IPSEC_ID_IPV6_RANGE:
                return -1;

        case IPSEC_ID_DER_ASN1_DN:
                return -1;

        case IPSEC_ID_DER_ASN1_GN:
                return -1;

        case IPSEC_ID_KEY_ID:
                return -1;
#endif

        default:
                log_print("ipsec_get_id: unknown ID type \"%s\" in "
                    "section %s", type, section);
                return -1;
        }

        return 0;
}

/*
 * XXX I rather want this function to return a status code, and fail if
 * we cannot fit the information in the supplied buffer.
 */
static void
ipsec_decode_id(char *buf, size_t size, u_int8_t *id, size_t id_len,
    int isakmpform)
{
        int             id_type;
        char           *addr = 0, *mask = 0;

        if (id) {
                if (!isakmpform) {
                        /*
                         * Exchanges and SAs dont carry the IDs in ISAKMP
                         * form.
                         */
                        id -= ISAKMP_GEN_SZ;
                        id_len += ISAKMP_GEN_SZ;
                }
                id_type = GET_ISAKMP_ID_TYPE(id);
                switch (id_type) {
                case IPSEC_ID_IPV4_ADDR:
                        util_ntoa(&addr, AF_INET, id + ISAKMP_ID_DATA_OFF);
                        snprintf(buf, size, "%s", addr);
                        break;

                case IPSEC_ID_IPV4_ADDR_SUBNET:
                        util_ntoa(&addr, AF_INET, id + ISAKMP_ID_DATA_OFF);
                        util_ntoa(&mask, AF_INET, id + ISAKMP_ID_DATA_OFF + 4);
                        snprintf(buf, size, "%s/%s", addr, mask);
                        break;

                case IPSEC_ID_IPV6_ADDR:
                        util_ntoa(&addr, AF_INET6, id + ISAKMP_ID_DATA_OFF);
                        snprintf(buf, size, "%s", addr);
                        break;

                case IPSEC_ID_IPV6_ADDR_SUBNET:
                        util_ntoa(&addr, AF_INET6, id + ISAKMP_ID_DATA_OFF);
                        util_ntoa(&mask, AF_INET6, id + ISAKMP_ID_DATA_OFF +
                            sizeof(struct in6_addr));
                        snprintf(buf, size, "%s/%s", addr, mask);
                        break;

                case IPSEC_ID_FQDN:
                case IPSEC_ID_USER_FQDN:
                        /* String is not NUL terminated, be careful */
                        id_len -= ISAKMP_ID_DATA_OFF;
                        id_len = MINIMUM(id_len, size - 1);
                        memcpy(buf, id + ISAKMP_ID_DATA_OFF, id_len);
                        buf[id_len] = '\0';
                        break;

                case IPSEC_ID_DER_ASN1_DN:
                        addr = x509_DN_string(id + ISAKMP_ID_DATA_OFF,
                            id_len - ISAKMP_ID_DATA_OFF);
                        if (!addr) {
                                snprintf(buf, size, "unparsable ASN1 DN ID");
                                return;
                        }
                        strlcpy(buf, addr, size);
                        break;

                default:
                        snprintf(buf, size, "<id type unknown: %x>", id_type);
                        break;
                }
        } else
                snprintf(buf, size, "<no ipsec id>");
        free(addr);
        free(mask);
}

char *
ipsec_decode_ids(char *fmt, u_int8_t *id1, size_t id1_len, u_int8_t *id2,
    size_t id2_len, int isakmpform)
{
        static char     result[1024];
        char            s_id1[256], s_id2[256];

        ipsec_decode_id(s_id1, sizeof s_id1, id1, id1_len, isakmpform);
        ipsec_decode_id(s_id2, sizeof s_id2, id2, id2_len, isakmpform);

        snprintf(result, sizeof result, fmt, s_id1, s_id2);
        return result;
}

/*
 * Out of a named section SECTION in the configuration file build an
 * ISAKMP ID payload.  Ths payload size should be stashed in SZ.
 * The caller is responsible for freeing the payload.
 */
u_int8_t *
ipsec_build_id(char *section, size_t *sz)
{
        struct sockaddr *addr, *mask;
        u_int8_t       *p;
        int             id, subnet = 0;
        u_int8_t        tproto = 0;
        u_int16_t       port = 0;

        if (ipsec_get_id(section, &id, &addr, &mask, &tproto, &port))
                return 0;

        if (id == IPSEC_ID_IPV4_ADDR_SUBNET || id == IPSEC_ID_IPV6_ADDR_SUBNET)
                subnet = 1;

        *sz = ISAKMP_ID_SZ + sockaddr_addrlen(addr);
        if (subnet)
                *sz += sockaddr_addrlen(mask);

        p = malloc(*sz);
        if (!p) {
                log_print("ipsec_build_id: malloc(%lu) failed",
                    (unsigned long)*sz);
                if (subnet)
                        free(mask);
                free(addr);
                return 0;
        }
        SET_ISAKMP_ID_TYPE(p, id);
        SET_ISAKMP_ID_DOI_DATA(p, (unsigned char *)"\000\000\000");

        memcpy(p + ISAKMP_ID_DATA_OFF, sockaddr_addrdata(addr),
            sockaddr_addrlen(addr));
        if (subnet)
                memcpy(p + ISAKMP_ID_DATA_OFF + sockaddr_addrlen(addr),
                    sockaddr_addrdata(mask), sockaddr_addrlen(mask));

        SET_IPSEC_ID_PROTO(p + ISAKMP_ID_DOI_DATA_OFF, tproto);
        SET_IPSEC_ID_PORT(p + ISAKMP_ID_DOI_DATA_OFF, port);

        if (subnet)
                free(mask);
        free(addr);
        return p;
}

/*
 * copy an ISAKMPD id
 */
int
ipsec_clone_id(u_int8_t **did, size_t *did_len, u_int8_t *id, size_t id_len)
{
        free(*did);

        if (!id_len || !id) {
                *did = 0;
                *did_len = 0;
                return 0;
        }
        *did = malloc(id_len);
        if (!*did) {
                *did_len = 0;
                log_error("ipsec_clone_id: malloc(%lu) failed",
                    (unsigned long)id_len);
                return -1;
        }
        *did_len = id_len;
        memcpy(*did, id, id_len);

        return 0;
}

/*
 * IPsec-specific PROTO initializations.  SECTION is only set if we are the
 * initiator thus only usable there.
 * XXX I want to fix this later.
 */
void
ipsec_proto_init(struct proto *proto, char *section)
{
        struct ipsec_proto *iproto = proto->data;

        if (proto->sa->phase == 2)
                iproto->replay_window = section ? conf_get_num(section,
                    "ReplayWindow", DEFAULT_REPLAY_WINDOW) :
                    DEFAULT_REPLAY_WINDOW;
}

/*
 * Add a notification payload of type INITIAL CONTACT to MSG if this is
 * the first contact we have made to our peer.
 */
int
ipsec_initial_contact(struct message *msg)
{
        u_int8_t *buf;

        if (ipsec_contacted(msg))
                return 0;

        buf = malloc(ISAKMP_NOTIFY_SZ + ISAKMP_HDR_COOKIES_LEN);
        if (!buf) {
                log_error("ike_phase_1_initial_contact: malloc (%d) failed",
                    ISAKMP_NOTIFY_SZ + ISAKMP_HDR_COOKIES_LEN);
                return -1;
        }
        SET_ISAKMP_NOTIFY_DOI(buf, IPSEC_DOI_IPSEC);
        SET_ISAKMP_NOTIFY_PROTO(buf, ISAKMP_PROTO_ISAKMP);
        SET_ISAKMP_NOTIFY_SPI_SZ(buf, ISAKMP_HDR_COOKIES_LEN);
        SET_ISAKMP_NOTIFY_MSG_TYPE(buf, IPSEC_NOTIFY_INITIAL_CONTACT);
        memcpy(buf + ISAKMP_NOTIFY_SPI_OFF, msg->isakmp_sa->cookies,
            ISAKMP_HDR_COOKIES_LEN);
        if (message_add_payload(msg, ISAKMP_PAYLOAD_NOTIFY, buf,
            ISAKMP_NOTIFY_SZ + ISAKMP_HDR_COOKIES_LEN, 1)) {
                free(buf);
                return -1;
        }
        return ipsec_add_contact(msg);
}

/*
 * Compare the two contacts pointed to by A and B.  Return negative if
 * *A < *B, 0 if they are equal, and positive if *A is the largest of them.
 */
static int
addr_cmp(const void *a, const void *b)
{
        const struct contact *x = a, *y = b;
        int             minlen = MINIMUM(x->len, y->len);
        int             rv = memcmp(x->addr, y->addr, minlen);

        return rv ? rv : (x->len - y->len);
}

/*
 * Add the peer that MSG is bound to as an address we don't want to send
 * INITIAL CONTACT too from now on.  Do not call this function with a
 * specific address duplicate times. We want fast lookup, speed of insertion
 * is unimportant, if this is to scale.
 */
static int
ipsec_add_contact(struct message *msg)
{
        struct contact *new_contacts;
        struct sockaddr *dst, *addr;
        int             cnt;

        if (contact_cnt == contact_limit) {
                cnt = contact_limit ? 2 * contact_limit : 64;
                new_contacts = reallocarray(contacts, cnt, sizeof contacts[0]);
                if (!new_contacts) {
                        log_error("ipsec_add_contact: "
                            "realloc (%p, %lu) failed", contacts,
                            cnt * (unsigned long) sizeof contacts[0]);
                        return -1;
                }
                contact_limit = cnt;
                contacts = new_contacts;
        }
        msg->transport->vtbl->get_dst(msg->transport, &dst);
        addr = malloc(SA_LEN(dst));
        if (!addr) {
                log_error("ipsec_add_contact: malloc (%lu) failed",
                    (unsigned long)SA_LEN(dst));
                return -1;
        }
        memcpy(addr, dst, SA_LEN(dst));
        contacts[contact_cnt].addr = addr;
        contacts[contact_cnt++].len = SA_LEN(dst);

        /*
         * XXX There are better algorithms for already mostly-sorted data like
         * this, but only qsort is standard.  I will someday do this inline.
         */
        qsort(contacts, contact_cnt, sizeof *contacts, addr_cmp);
        return 0;
}

/* Return true if the recipient of MSG has already been contacted.  */
static int
ipsec_contacted(struct message *msg)
{
        struct contact  contact;

        msg->transport->vtbl->get_dst(msg->transport, &contact.addr);
        contact.len = SA_LEN(contact.addr);
        return contacts ? (bsearch(&contact, contacts, contact_cnt,
            sizeof *contacts, addr_cmp) != 0) : 0;
}

/* Add a HASH for to MSG.  */
u_int8_t *
ipsec_add_hash_payload(struct message *msg, size_t hashsize)
{
        u_int8_t *buf;

        buf = malloc(ISAKMP_HASH_SZ + hashsize);
        if (!buf) {
                log_error("ipsec_add_hash_payload: malloc (%lu) failed",
                    ISAKMP_HASH_SZ + (unsigned long) hashsize);
                return 0;
        }
        if (message_add_payload(msg, ISAKMP_PAYLOAD_HASH, buf,
            ISAKMP_HASH_SZ + hashsize, 1)) {
                free(buf);
                return 0;
        }
        return buf;
}

/* Fill in the HASH payload of MSG.  */
int
ipsec_fill_in_hash(struct message *msg)
{
        struct exchange *exchange = msg->exchange;
        struct sa      *isakmp_sa = msg->isakmp_sa;
        struct ipsec_sa *isa = isakmp_sa->data;
        struct hash    *hash = hash_get(isa->hash);
        struct prf     *prf;
        struct payload *payload;
        u_int8_t       *buf;
        u_int32_t       i;
        char            header[80];

        /* If no SKEYID_a, we need not do anything.  */
        if (!isa->skeyid_a)
                return 0;

        payload = payload_first(msg, ISAKMP_PAYLOAD_HASH);
        if (!payload) {
                log_print("ipsec_fill_in_hash: no HASH payload found");
                return -1;
        }
        buf = payload->p;

        /* Allocate the prf and start calculating our HASH(1).  */
        LOG_DBG_BUF((LOG_MISC, 90, "ipsec_fill_in_hash: SKEYID_a",
            isa->skeyid_a, isa->skeyid_len));
        prf = prf_alloc(isa->prf_type, hash->type, isa->skeyid_a,
            isa->skeyid_len);
        if (!prf)
                return -1;

        prf->Init(prf->prfctx);
        LOG_DBG_BUF((LOG_MISC, 90, "ipsec_fill_in_hash: message_id",
            exchange->message_id, ISAKMP_HDR_MESSAGE_ID_LEN));
        prf->Update(prf->prfctx, exchange->message_id,
            ISAKMP_HDR_MESSAGE_ID_LEN);

        /* Loop over all payloads after HASH(1).  */
        for (i = 2; i < msg->iovlen; i++) {
                /* XXX Misleading payload type printouts.  */
                snprintf(header, sizeof header,
                    "ipsec_fill_in_hash: payload %d after HASH(1)", i - 1);
                LOG_DBG_BUF((LOG_MISC, 90, header, msg->iov[i].iov_base,
                    msg->iov[i].iov_len));
                prf->Update(prf->prfctx, msg->iov[i].iov_base,
                    msg->iov[i].iov_len);
        }
        prf->Final(buf + ISAKMP_HASH_DATA_OFF, prf->prfctx);
        prf_free(prf);
        LOG_DBG_BUF((LOG_MISC, 80, "ipsec_fill_in_hash: HASH(1)", buf +
            ISAKMP_HASH_DATA_OFF, hash->hashsize));

        return 0;
}

/* Add a HASH payload to MSG, if we have an ISAKMP SA we're protected by.  */
static int
ipsec_informational_pre_hook(struct message *msg)
{
        struct sa      *isakmp_sa = msg->isakmp_sa;
        struct ipsec_sa *isa;
        struct hash    *hash;

        if (!isakmp_sa)
                return 0;
        isa = isakmp_sa->data;
        hash = hash_get(isa->hash);
        return ipsec_add_hash_payload(msg, hash->hashsize) == 0;
}

/*
 * Fill in the HASH payload in MSG, if we have an ISAKMP SA we're protected by.
 */
static int
ipsec_informational_post_hook(struct message *msg)
{
        if (!msg->isakmp_sa)
                return 0;
        return ipsec_fill_in_hash(msg);
}

ssize_t
ipsec_id_size(char *section, u_int8_t *id)
{
        char *type, *data;

        type = conf_get_str(section, "ID-type");
        if (!type) {
                log_print("ipsec_id_size: section %s has no \"ID-type\" tag",
                    section);
                return -1;
        }
        *id = constant_value(ipsec_id_cst, type);
        switch (*id) {
        case IPSEC_ID_IPV4_ADDR:
                return sizeof(struct in_addr);
        case IPSEC_ID_IPV4_ADDR_SUBNET:
                return 2 * sizeof(struct in_addr);
        case IPSEC_ID_IPV6_ADDR:
                return sizeof(struct in6_addr);
        case IPSEC_ID_IPV6_ADDR_SUBNET:
                return 2 * sizeof(struct in6_addr);
        case IPSEC_ID_FQDN:
        case IPSEC_ID_USER_FQDN:
        case IPSEC_ID_KEY_ID:
        case IPSEC_ID_DER_ASN1_DN:
        case IPSEC_ID_DER_ASN1_GN:
                data = conf_get_str(section, "Name");
                if (!data) {
                        log_print("ipsec_id_size: "
                            "section %s has no \"Name\" tag", section);
                        return -1;
                }
                return strlen(data);
        }
        log_print("ipsec_id_size: unrecognized/unsupported ID-type %d (%s)",
            *id, type);
        return -1;
}

/*
 * Generate a string version of the ID.
 */
char *
ipsec_id_string(u_int8_t *id, size_t id_len)
{
        char           *buf = 0;
        char           *addrstr = 0;
        size_t          len, size;

        /*
         * XXX Real ugly way of making the offsets correct.  Be aware that id
         * now will point before the actual buffer and cannot be dereferenced
         * without an offset larger than or equal to ISAKM_GEN_SZ.
         */
        id -= ISAKMP_GEN_SZ;

        /* This is the actual length of the ID data field.  */
        id_len += ISAKMP_GEN_SZ - ISAKMP_ID_DATA_OFF;

        /*
         * Conservative allocation.
         * XXX I think the ASN1 DN case can be thought through to give a better
         * estimate.
         */
        size = MAXIMUM(sizeof "ipv6/ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff",
            sizeof "asn1_dn/" + id_len);
        buf = malloc(size);
        if (!buf)
                /* XXX Log?  */
                goto fail;

        switch (GET_ISAKMP_ID_TYPE(id)) {
        case IPSEC_ID_IPV4_ADDR:
                if (id_len < sizeof(struct in_addr))
                        goto fail;
                util_ntoa(&addrstr, AF_INET, id + ISAKMP_ID_DATA_OFF);
                if (!addrstr)
                        goto fail;
                snprintf(buf, size, "ipv4/%s", addrstr);
                break;

        case IPSEC_ID_IPV6_ADDR:
                if (id_len < sizeof(struct in6_addr))
                        goto fail;
                util_ntoa(&addrstr, AF_INET6, id + ISAKMP_ID_DATA_OFF);
                if (!addrstr)
                        goto fail;
                snprintf(buf, size, "ipv6/%s", addrstr);
                break;

        case IPSEC_ID_FQDN:
        case IPSEC_ID_USER_FQDN:
                strlcpy(buf, GET_ISAKMP_ID_TYPE(id) == IPSEC_ID_FQDN ?
                    "fqdn/" : "ufqdn/", size);
                len = strlen(buf);

                memcpy(buf + len, id + ISAKMP_ID_DATA_OFF, id_len);
                *(buf + len + id_len) = '\0';
                break;

        case IPSEC_ID_DER_ASN1_DN:
                strlcpy(buf, "asn1_dn/", size);
                len = strlen(buf);
                addrstr = x509_DN_string(id + ISAKMP_ID_DATA_OFF, id_len);
                if (!addrstr)
                        goto fail;
                if (size < len + strlen(addrstr) + 1)
                        goto fail;
                strlcpy(buf + len, addrstr, size - len);
                break;

        default:
                /* Unknown type.  */
                LOG_DBG((LOG_MISC, 10,
                    "ipsec_id_string: unknown identity type %d\n",
                    GET_ISAKMP_ID_TYPE(id)));
                goto fail;
        }

        free(addrstr);
        return buf;

fail:
        free(buf);
        free(addrstr);
        return 0;
}