[strongswan.git] / src / pluto / connections.c

/* information about connections between hosts and clients
 * Copyright (C) 1998-2002  D. Hugh Redelmeier.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * RCSID $Id$
 */

#include <string.h>
#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <unistd.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <resolv.h>
#include <arpa/nameser.h>       /* missing from <resolv.h> on old systems */
#include <sys/queue.h>

#include <freeswan.h>
#include <ipsec_policy.h>
#include "kameipsec.h"

#include "constants.h"
#include "defs.h"
#include "id.h"
#include "x509.h"
#include "ca.h"
#include "crl.h"
#include "pgp.h"
#include "certs.h"
#include "ac.h"
#include "smartcard.h"
#include "fetch.h"
#include "connections.h"
#include "foodgroups.h"
#include "demux.h"
#include "state.h"
#include "timer.h"
#include "ipsec_doi.h"  /* needs demux.h and state.h */
#include "server.h"
#include "kernel.h"
#include "log.h"
#include "keys.h"
#include "adns.h"       /* needs <resolv.h> */
#include "dnskey.h"     /* needs keys.h and adns.h */
#include "whack.h"
#include "alg_info.h"
#include "ike_alg.h"
#include "kernel_alg.h"
#include "nat_traversal.h"
#include "virtual.h"

static void flush_pending_by_connection(struct connection *c);  /* forward */

static struct connection *connections = NULL;

/* struct host_pair: a nexus of information about a pair of hosts.
 * A host is an IP address, UDP port pair.  This is a debatable choice:
 * - should port be considered (no choice of port in standard)?
 * - should ID be considered (hard because not always known)?
 * - should IP address matter on our end (we don't know our end)?
 * Only oriented connections are registered.
 * Unoriented connections are kept on the unoriented_connections
 * linked list (using hp_next).  For them, host_pair is NULL.
 */

struct host_pair {
    struct {
        ip_address addr;
        u_int16_t port; /* host order */
    } me, him;
    bool initial_connection_sent;
    struct connection *connections;     /* connections with this pair */
    struct pending *pending;    /* awaiting Keying Channel */
    struct host_pair *next;
};

static struct host_pair *host_pairs = NULL;

static struct connection *unoriented_connections = NULL;

/* check to see that Ids of peers match */
bool
same_peer_ids(const struct connection *c, const struct connection *d
, const struct id *his_id)
{
    return same_id(&c->spd.this.id, &d->spd.this.id)
        && same_id(his_id == NULL? &c->spd.that.id : his_id, &d->spd.that.id);
}

static struct host_pair *
find_host_pair(const ip_address *myaddr, u_int16_t myport
, const ip_address *hisaddr, u_int16_t hisport)
{
    struct host_pair *p, *prev;

    /* default hisaddr to an appropriate any */
    if (hisaddr == NULL)
        hisaddr = aftoinfo(addrtypeof(myaddr))->any;
        
    if (nat_traversal_enabled)
    {
        /**
         * port is not relevant in host_pair. with nat_traversal we
         * always use pluto_port (500)
         */
        myport = pluto_port;
        hisport = pluto_port;
    }

    for (prev = NULL, p = host_pairs; p != NULL; prev = p, p = p->next)
    {
        if (sameaddr(&p->me.addr, myaddr) && p->me.port == myport
        &&  sameaddr(&p->him.addr, hisaddr) && p->him.port == hisport)
        {
            if (prev != NULL)
            {
                prev->next = p->next;   /* remove p from list */
                p->next = host_pairs;   /* and stick it on front */
                host_pairs = p;
            }
            break;
        }
    }
    return p;
}

/* find head of list of connections with this pair of hosts */
static struct connection *
find_host_pair_connections(const ip_address *myaddr, u_int16_t myport
, const ip_address *hisaddr, u_int16_t hisport)
{
    struct host_pair *hp = find_host_pair(myaddr, myport, hisaddr, hisport);

    if (nat_traversal_enabled && hp && hisaddr)
    {
        struct connection *c;

        for (c = hp->connections; c != NULL; c = c->hp_next)
        {
            if (c->spd.this.host_port == myport && c->spd.that.host_port == hisport)
                return c;
        }
        return NULL;
    }
    return hp == NULL? NULL : hp->connections;
}

static void
connect_to_host_pair(struct connection *c)
{
    if (oriented(*c))
    {
        struct host_pair *hp;

        ip_address his_addr = (c->spd.that.allow_any)
                              ? *aftoinfo(addrtypeof(&c->spd.that.host_addr))->any
                              : c->spd.that.host_addr;

        hp = find_host_pair(&c->spd.this.host_addr, c->spd.this.host_port
            , &his_addr, c->spd.that.host_port);

        if (hp == NULL)
        {
            /* no suitable host_pair -- build one */
            hp = alloc_thing(struct host_pair, "host_pair");
            hp->me.addr = c->spd.this.host_addr;
            hp->him.addr = his_addr;
            hp->me.port = nat_traversal_enabled ? pluto_port : c->spd.this.host_port;
            hp->him.port = nat_traversal_enabled ? pluto_port : c->spd.that.host_port;
            hp->initial_connection_sent = FALSE;
            hp->connections = NULL;
            hp->pending = NULL;
            hp->next = host_pairs;
            host_pairs = hp;
        }
        c->host_pair = hp;
        c->hp_next = hp->connections;
        hp->connections = c;
    }
    else
    {
        /* since this connection isn't oriented, we place it
         * in the unoriented_connections list instead.
         */
        c->host_pair = NULL;
        c->hp_next = unoriented_connections;
        unoriented_connections = c;
    }
}

/* find a connection by name.
 * If strict, don't accept a CK_INSTANCE.
 * Move the winner (if any) to the front.
 * If none is found, and strict, a diagnostic is logged to whack.
 */
struct connection *
con_by_name(const char *nm, bool strict)
{
    struct connection *p, *prev;

    for (prev = NULL, p = connections; ; prev = p, p = p->ac_next)
    {
        if (p == NULL)
        {
            if (strict)
                whack_log(RC_UNKNOWN_NAME
                    , "no connection named \"%s\"", nm);
            break;
        }
        if (streq(p->name, nm)
        && (!strict || p->kind != CK_INSTANCE))
        {
            if (prev != NULL)
            {
                prev->ac_next = p->ac_next;     /* remove p from list */
                p->ac_next = connections;       /* and stick it on front */
                connections = p;
            }
            break;
        }
    }
    return p;
}

void
release_connection(struct connection *c, bool relations)
{
    if (c->kind == CK_INSTANCE)
    {
        /* This does everything we need.
         * Note that we will be called recursively by delete_connection,
         * but kind will be CK_GOING_AWAY.
         */
        delete_connection(c, relations);
    }
    else
    {
        flush_pending_by_connection(c);
        delete_states_by_connection(c, relations);
        unroute_connection(c);
    }
}

/* Delete a connection */

#define list_rm(etype, enext, e, ehead) { \
        etype **ep; \
        for (ep = &(ehead); *ep != (e); ep = &(*ep)->enext) \
            passert(*ep != NULL);    /* we must not come up empty-handed */ \
        *ep = (e)->enext; \
    }


void
delete_connection(struct connection *c, bool relations)
{
    struct connection *old_cur_connection
        = cur_connection == c? NULL : cur_connection;
#ifdef DEBUG
    lset_t old_cur_debugging = cur_debugging;
#endif

    set_cur_connection(c);

    /* Must be careful to avoid circularity:
     * we mark c as going away so it won't get deleted recursively.
     */
    passert(c->kind != CK_GOING_AWAY);
    if (c->kind == CK_INSTANCE)
    {
        plog("deleting connection \"%s\" instance with peer %s {isakmp=#%lu/ipsec=#%lu}"
             , c->name
             , ip_str(&c->spd.that.host_addr)
             , c->newest_isakmp_sa, c->newest_ipsec_sa);
        c->kind = CK_GOING_AWAY;
    }
    else
    {
        plog("deleting connection");
    }
    release_connection(c, relations);   /* won't delete c */

    if (c->kind == CK_GROUP)
        delete_group(c);

    /* free up any logging resources */
    perpeer_logfree(c);

    /* find and delete c from connections list */
    list_rm(struct connection, ac_next, c, connections);
    cur_connection = old_cur_connection;

    /* find and delete c from the host pair list */
    if (c->host_pair == NULL)
    {
        if (c->ikev1)
            list_rm(struct connection, hp_next, c, unoriented_connections);
    }
    else
    {
        struct host_pair *hp = c->host_pair;

        list_rm(struct connection, hp_next, c, hp->connections);
        c->host_pair = NULL;    /* redundant, but safe */

        /* if there are no more connections with this host_pair
         * and we haven't even made an initial contact, let's delete
         * this guy in case we were created by an attempted DOS attack.
         */
        if (hp->connections == NULL
        && !hp->initial_connection_sent)
        {
            passert(hp->pending == NULL);       /* ??? must deal with this! */
            list_rm(struct host_pair, next, hp, host_pairs);
            pfree(hp);
        }
    }

    if (c->kind != CK_GOING_AWAY)
        pfreeany(c->spd.that.virt);

#ifdef DEBUG
    cur_debugging = old_cur_debugging;
#endif
    pfreeany(c->name);
    free_id_content(&c->spd.this.id);
    pfreeany(c->spd.this.updown);
    freeanychunk(c->spd.this.ca);
    free_ietfAttrList(c->spd.this.groups);
    free_id_content(&c->spd.that.id);
    pfreeany(c->spd.that.updown);
    freeanychunk(c->spd.that.ca);
    free_ietfAttrList(c->spd.that.groups);
    free_generalNames(c->requested_ca, TRUE);
    gw_delref(&c->gw_info);

    lock_certs_and_keys("delete_connection");
    release_cert(c->spd.this.cert);
    scx_release(c->spd.this.sc);
    release_cert(c->spd.that.cert);
    scx_release(c->spd.that.sc);
    unlock_certs_and_keys("delete_connection");

    alg_info_delref((struct alg_info **)&c->alg_info_esp);
    alg_info_delref((struct alg_info **)&c->alg_info_ike);

    pfree(c);
}

/* Delete connections with the specified name */
void
delete_connections_by_name(const char *name, bool strict)
{
    struct connection *c = con_by_name(name, strict);

    for (; c != NULL; c = con_by_name(name, FALSE))
        delete_connection(c, FALSE);
}

void
delete_every_connection(void)
{
    while (connections != NULL)
        delete_connection(connections, TRUE);
}

void
release_dead_interfaces(void)
{
    struct host_pair *hp;

    for (hp = host_pairs; hp != NULL; hp = hp->next)
    {
        struct connection **pp
            , *p;

        for (pp = &hp->connections; (p = *pp) != NULL; )
        {
            if (p->interface->change == IFN_DELETE)
            {
                /* this connection's interface is going away */
                enum connection_kind k = p->kind;

                release_connection(p, TRUE);

                if (k <= CK_PERMANENT)
                {
                    /* The connection should have survived release:
                     * move it to the unoriented_connections list.
                     */
                    passert(p == *pp);

                    p->interface = NULL;

                    *pp = p->hp_next;   /* advance *pp */
                    p->host_pair = NULL;
                    p->hp_next = unoriented_connections;
                    unoriented_connections = p;
                }
                else
                {
                    /* The connection should have vanished,
                     * but the previous connection remains.
                     */
                    passert(p != *pp);
                }
            }
            else
            {
                pp = &p->hp_next;       /* advance pp */
            }
        }
    }
}

/* adjust orientations of connections to reflect newly added interfaces */
void
check_orientations(void)
{
    /* try to orient all the unoriented connections */
    {
        struct connection *c = unoriented_connections;

        unoriented_connections = NULL;

        while (c != NULL)
        {
            struct connection *nxt = c->hp_next;

            (void)orient(c);
            connect_to_host_pair(c);
            c = nxt;
        }
    }

    /* Check that no oriented connection has become double-oriented.
     * In other words, the far side must not match one of our new interfaces.
     */
    {
        struct iface *i;

        for (i = interfaces; i != NULL; i = i->next)
        {
            if (i->change == IFN_ADD)
            {
                struct host_pair *hp;

                for (hp = host_pairs; hp != NULL; hp = hp->next)
                {
                    if (sameaddr(&hp->him.addr, &i->addr)
                    && (!no_klips || hp->him.port == pluto_port))
                    {
                        /* bad news: the whole chain of connections
                         * hanging off this host pair has both sides
                         * matching an interface.
                         * We'll get rid of them, using orient and
                         * connect_to_host_pair.  But we'll be lazy
                         * and not ditch the host_pair itself (the
                         * cost of leaving it is slight and cannot
                         * be induced by a foe).
                         */
                        struct connection *c = hp->connections;

                        hp->connections = NULL;
                        while (c != NULL)
                        {
                            struct connection *nxt = c->hp_next;

                            c->interface = NULL;
                            (void)orient(c);
                            connect_to_host_pair(c);
                            c = nxt;
                        }
                    }
                }
            }
        }
    }
}

static err_t
default_end(struct end *e, ip_address *dflt_nexthop)
{
    err_t ugh = NULL;
    const struct af_info *afi = aftoinfo(addrtypeof(&e->host_addr));

    if (afi == NULL)
        return "unknown address family in default_end";

    /* default ID to IP (but only if not NO_IP -- WildCard) */
    if (e->id.kind == ID_NONE && !isanyaddr(&e->host_addr))
    {
        e->id.kind = afi->id_addr;
        e->id.ip_addr = e->host_addr;
        e->has_id_wildcards = FALSE;
    }

    /* default nexthop to other side */
    if (isanyaddr(&e->host_nexthop))
        e->host_nexthop = *dflt_nexthop;

    /* default client to subnet containing only self
     * XXX This may mean that the client's address family doesn't match
     * tunnel_addr_family.
     */
    if (!e->has_client)
        ugh = addrtosubnet(&e->host_addr, &e->client);

    return ugh;
}

/* Format the topology of a connection end, leaving out defaults.
 * Largest left end looks like: client === host : port [ host_id ] --- hop
 * Note: if that==NULL, skip nexthop
 * Returns strlen of formated result (length excludes NUL at end).
 */
size_t
format_end(char *buf
, size_t buf_len
, const struct end *this
, const struct end *that
, bool is_left
, lset_t policy)
{
    char client[SUBNETTOT_BUF];
    const char *client_sep = "";
    char protoport[sizeof(":255/65535")];
    const char *host = NULL;
    char host_space[ADDRTOT_BUF];
    char host_port[sizeof(":65535")];
    char host_id[BUF_LEN + 2];
    char hop[ADDRTOT_BUF];
    const char *hop_sep = "";
    const char *open_brackets  = "";
    const char *close_brackets = "";

    if (isanyaddr(&this->host_addr))
    {
        switch (policy & (POLICY_GROUP | POLICY_OPPO))
        {
        case POLICY_GROUP:
            host = "%group";
            break;
        case POLICY_OPPO:
            host = "%opportunistic";
            break;
        case POLICY_GROUP | POLICY_OPPO:
            host = "%opportunisticgroup";
            break;
        default:
            host = "%any";
            break;
        }
    }

    client[0] = '\0';

    if (is_virtual_end(this) && isanyaddr(&this->host_addr))
    {
        host = "%virtual";
    }

    /* [client===] */
    if (this->has_client)
    {
        ip_address client_net, client_mask;

        networkof(&this->client, &client_net);
        maskof(&this->client, &client_mask);
        client_sep = "===";

        /* {client_subnet_wildcard} */
        if (this->has_client_wildcard)
        {
            open_brackets  = "{";
            close_brackets = "}";
        }

        if (isanyaddr(&client_net) && isanyaddr(&client_mask)
        && (policy & (POLICY_GROUP | POLICY_OPPO)))
            client_sep = "";    /* boring case */
        else if (subnetisnone(&this->client))
            strcpy(client, "?");
        else
            subnettot(&this->client, 0, client, sizeof(client));
    }
    else if (this->modecfg && isanyaddr(&this->host_srcip))
    {
        /* we are mode config client */
        client_sep = "===";
        strcpy(client, "%modecfg");
    }

    /* host */
    if (host == NULL)
    {
        addrtot(&this->host_addr, 0, host_space, sizeof(host_space));
        host = host_space;
    }

    host_port[0] = '\0';
    if (this->host_port != IKE_UDP_PORT)
        snprintf(host_port, sizeof(host_port), ":%u"
            , this->host_port);

    /* payload portocol and port */
    protoport[0] = '\0';
    if (this->has_port_wildcard)
        snprintf(protoport, sizeof(protoport), ":%u/%%any", this->protocol);
    else if (this->port || this->protocol)
        snprintf(protoport, sizeof(protoport), ":%u/%u", this->protocol
            , this->port);

    /* id, if different from host */
    host_id[0] = '\0';
    if (this->id.kind == ID_MYID)
    {
        strcpy(host_id, "[%myid]");
    }
    else if (!(this->id.kind == ID_NONE
    || (id_is_ipaddr(&this->id) && sameaddr(&this->id.ip_addr, &this->host_addr))))
    {
        int len = idtoa(&this->id, host_id+1, sizeof(host_id)-2);

        host_id[0] = '[';
        strcpy(&host_id[len < 0? (ptrdiff_t)sizeof(host_id)-2 : 1 + len], "]");
    }

    /* [---hop] */
    hop[0] = '\0';
    hop_sep = "";
    if (that != NULL && !sameaddr(&this->host_nexthop, &that->host_addr))
    {
        addrtot(&this->host_nexthop, 0, hop, sizeof(hop));
        hop_sep = "---";
    }

    if (is_left)
        snprintf(buf, buf_len, "%s%s%s%s%s%s%s%s%s%s%s"
            , open_brackets, client, close_brackets, client_sep
            , this->allow_any? "%":""
            , host, host_port, host_id, protoport
            , hop_sep, hop);
    else
        snprintf(buf, buf_len, "%s%s%s%s%s%s%s%s%s%s%s"
            , hop, hop_sep
            , this->allow_any? "%":""
            , host, host_port, host_id, protoport, client_sep
            , open_brackets, client, close_brackets);
    return strlen(buf);
}

/* format topology of a connection.
 * Two symmetric ends separated by ...
 */
#define CONNECTION_BUF  (2 * (END_BUF - 1) + 4)

static size_t
format_connection(char *buf, size_t buf_len
                  , const struct connection *c
                  , struct spd_route *sr)
{
    size_t w = format_end(buf, buf_len, &sr->this, &sr->that, TRUE, LEMPTY);

    w += snprintf(buf + w, buf_len - w, "...");
    return w + format_end(buf + w, buf_len - w, &sr->that, &sr->this, FALSE, c->policy);
}

static void
unshare_connection_strings(struct connection *c)
{
    c->name = clone_str(c->name, "connection name");

    unshare_id_content(&c->spd.this.id);
    c->spd.this.updown = clone_str(c->spd.this.updown, "updown");
    scx_share(c->spd.this.sc);
    share_cert(c->spd.this.cert);
    if (c->spd.this.ca.ptr != NULL)
        clonetochunk(c->spd.this.ca, c->spd.this.ca.ptr, c->spd.this.ca.len, "ca string");

    unshare_id_content(&c->spd.that.id);
    c->spd.that.updown = clone_str(c->spd.that.updown, "updown");
    scx_share(c->spd.that.sc);
    share_cert(c->spd.that.cert);
    if (c->spd.that.ca.ptr != NULL)
        clonetochunk(c->spd.that.ca, c->spd.that.ca.ptr, c->spd.that.ca.len, "ca string");

    /* increment references to algo's */
    alg_info_addref((struct alg_info *)c->alg_info_esp);
    alg_info_addref((struct alg_info *)c->alg_info_ike);
}

static void
load_end_certificate(const char *filename, struct end *dst)
{
    time_t valid_until;
    cert_t cert;
    bool valid_cert = FALSE;
    bool cached_cert = FALSE;

    /* initialize end certificate */
    dst->cert.type = CERT_NONE;
    dst->cert.u.x509 = NULL;

    /* initialize smartcard info record */
    dst->sc = NULL;

    if (filename != NULL)
    {
        if (scx_on_smartcard(filename))
        {
            /* load cert from smartcard */
            valid_cert = scx_load_cert(filename, &dst->sc, &cert, &cached_cert);
        }
        else
        {
            /* load cert from file */
            valid_cert = load_host_cert(filename, &cert);
        }
    }

    if (valid_cert)
    {
        err_t ugh = NULL;

        switch (cert.type)
        {
        case CERT_PGP:
            select_pgpcert_id(cert.u.pgp, &dst->id);

            if (cached_cert)
                dst->cert = cert;
            else
            {
                valid_until = cert.u.pgp->until;
                add_pgp_public_key(cert.u.pgp, cert.u.pgp->until, DAL_LOCAL);
                dst->cert.type = cert.type;
                dst->cert.u.pgp = add_pgpcert(cert.u.pgp);
            }
            break;
        case CERT_X509_SIGNATURE:
            select_x509cert_id(cert.u.x509, &dst->id);

            if (cached_cert)
                dst->cert = cert;
            else
            {
                /* check validity of cert */
                valid_until = cert.u.x509->notAfter;
                ugh = check_validity(cert.u.x509, &valid_until);
                if (ugh != NULL)
                {
                    plog("  %s", ugh);
                    free_x509cert(cert.u.x509);
                    break;
                }

                DBG(DBG_CONTROL,
                    DBG_log("certificate is valid")
                )
                add_x509_public_key(cert.u.x509, valid_until, DAL_LOCAL);
                dst->cert.type = cert.type;
                dst->cert.u.x509 = add_x509cert(cert.u.x509);
            }
            /* if no CA is defined, use issuer as default */
            if (dst->ca.ptr == NULL)
                dst->ca = dst->cert.u.x509->issuer;
            break;
        default:
            break;
        }

        /* cache the certificate that was last retrieved from the smartcard */
        if (dst->sc != NULL)
        {
            if (!same_cert(&dst->sc->last_cert, &dst->cert))
            {
                lock_certs_and_keys("load_end_certificates");
                release_cert(dst->sc->last_cert);
                dst->sc->last_cert = dst->cert;
                share_cert(dst->cert);
                unlock_certs_and_keys("load_end_certificates");
            }
            time(&dst->sc->last_load);
        }
    }
}

static bool
extract_end(struct end *dst, const whack_end_t *src, const char *which)
{
    bool same_ca = FALSE;

    /* decode id, if any */
    if (src->id == NULL)
    {
        dst->id.kind = ID_NONE;
    }
    else
    {
        err_t ugh = atoid(src->id, &dst->id, TRUE);

        if (ugh != NULL)
        {
            loglog(RC_BADID, "bad %s --id: %s (ignored)", which, ugh);
            dst->id = empty_id; /* ignore bad one */
        }
    }

    dst->ca = empty_chunk;

    /* decode CA distinguished name, if any */
    if (src->ca != NULL)
    {
        if streq(src->ca, "%same")
            same_ca = TRUE;
        else if (!streq(src->ca, "%any"))
        {
            err_t ugh;

            dst->ca.ptr = temporary_cyclic_buffer();
            ugh = atodn(src->ca, &dst->ca);
            if (ugh != NULL)
            {
                plog("bad CA string '%s': %s (ignored)", src->ca, ugh);
                dst->ca = empty_chunk;
            }
        }
    }

    /* load local end certificate and extract ID, if any */
    load_end_certificate(src->cert, dst);

    /* does id has wildcards? */
    dst->has_id_wildcards = id_count_wildcards(&dst->id) > 0;

    /* decode group attributes, if any */
    decode_groups(src->groups, &dst->groups);

    /* the rest is simple copying of corresponding fields */
    dst->host_addr = src->host_addr;
    dst->host_nexthop = src->host_nexthop;
    dst->host_srcip = src->host_srcip;
    dst->has_natip = src->has_natip;
    dst->client = src->client;
    dst->protocol = src->protocol;
    dst->port = src->port;
    dst->has_port_wildcard = src->has_port_wildcard;
    dst->key_from_DNS_on_demand = src->key_from_DNS_on_demand;
    dst->has_client = src->has_client;
    dst->has_client_wildcard = src->has_client_wildcard;
    dst->modecfg = src->modecfg;
    dst->hostaccess = src->hostaccess;
    dst->allow_any = src->allow_any;
    dst->sendcert = src->sendcert;
    dst->updown = src->updown;
    dst->host_port = src->host_port;

    /* if host sourceip is defined but no client is present
     * behind the host then set client to sourceip/32
     */
    if (addrbytesptr(&dst->host_srcip, NULL)
    && !isanyaddr(&dst->host_srcip)
    && !dst->has_natip
    && !dst->has_client)
    {
        err_t ugh = addrtosubnet(&dst->host_srcip, &dst->client);

        if (ugh != NULL)
            plog("could not assign host sourceip to client subnet");
        else
            dst->has_client = TRUE;
    }
    return same_ca;
}

static bool
check_connection_end(const whack_end_t *this, const whack_end_t *that
, const whack_message_t *wm)
{
    if (wm->addr_family != addrtypeof(&this->host_addr)
    || wm->addr_family != addrtypeof(&this->host_nexthop)
    || (this->has_client? wm->tunnel_addr_family : wm->addr_family)
      != subnettypeof(&this->client)
    || subnettypeof(&this->client) != subnettypeof(&that->client))
    {
        /* this should have been diagnosed by whack, so we need not be clear
         * !!! overloaded use of RC_CLASH
         */
        loglog(RC_CLASH, "address family inconsistency in connection");
        return FALSE;
    }

    if (isanyaddr(&that->host_addr))
    {
        /* other side is wildcard: we must check if other conditions met */
        if (isanyaddr(&this->host_addr))
        {
            loglog(RC_ORIENT, "connection must specify host IP address for our side");
            return FALSE;
        }
    }

    if (this->virt && (!isanyaddr(&this->host_addr) || this->has_client))
    {
        loglog(RC_CLASH,
            "virtual IP must only be used with %%any and without client");
        return FALSE;
    }

    return TRUE;        /* happy */
}

struct connection *
find_connection_by_reqid(uint32_t reqid)
{
    struct connection *c;

    reqid &= ~3;
    for (c = connections; c != NULL; c = c->ac_next)
    {
        if (c->spd.reqid == reqid)
            return c;
    }

    return NULL;
}

static uint32_t
gen_reqid(void)
{
    uint32_t start;
    static uint32_t reqid = IPSEC_MANUAL_REQID_MAX & ~3;

    start = reqid;
    do {
        reqid += 4;
        if (reqid == 0)
            reqid = (IPSEC_MANUAL_REQID_MAX & ~3) + 4;
        if (!find_connection_by_reqid(reqid))
            return reqid;
    } while (reqid != start);

    exit_log("unable to allocate reqid");
    return 0; /* never reached ... */
}

void
add_connection(const whack_message_t *wm)
{
    if (con_by_name(wm->name, FALSE) != NULL)
    {
        loglog(RC_DUPNAME, "attempt to redefine connection \"%s\"", wm->name);
    }
    else if (wm->right.protocol != wm->left.protocol)
    {
        /* this should haven been diagnosed by whack
         * !!! overloaded use of RC_CLASH
         */
        loglog(RC_CLASH, "the protocol must be the same for leftport and rightport");
    }
    else if (check_connection_end(&wm->right, &wm->left, wm)
    && check_connection_end(&wm->left, &wm->right, wm))
    {
        bool same_rightca, same_leftca;
        struct connection *c = alloc_thing(struct connection, "struct connection");

        c->name   = wm->name;
        c->ikev1  = wm->ikev1;
        c->policy = wm->policy;

        if ((c->policy & POLICY_COMPRESS) && !can_do_IPcomp)
            loglog(RC_COMMENT
                , "ignoring --compress in \"%s\" because KLIPS is not configured to do IPCOMP"
                , c->name);

        if (wm->esp)
        {
            const char *ugh;

             DBG(DBG_CONTROL,
                DBG_log("from whack: got --esp=%s", wm->esp ? wm->esp: "NULL")
            )
            c->alg_info_esp= alg_info_esp_create_from_str(wm->esp? wm->esp : "", &ugh);

            DBG(DBG_CRYPT|DBG_CONTROL,
                static char buf[256]="<NULL>";

                if (c->alg_info_esp)
                    alg_info_snprint(buf, sizeof(buf)
                            ,(struct alg_info *)c->alg_info_esp);
                DBG_log("esp string values: %s", buf);
            )
            if (c->alg_info_esp)
            {
                if (c->alg_info_esp->alg_info_cnt==0)
                     loglog(RC_LOG_SERIOUS
                            , "got 0 transforms for esp=\"%s\"", wm->esp);
            }
            else
            {
                loglog(RC_LOG_SERIOUS
                       , "esp string error: %s", ugh? ugh : "Unknown");
            }
        }
        
        if (wm->ike)
        {
            const char *ugh;

            DBG(DBG_CONTROL,
                DBG_log("from whack: got --ike=%s", wm->ike ? wm->ike: "NULL")
            )
            c->alg_info_ike= alg_info_ike_create_from_str(wm->ike? wm->ike : "", &ugh);

            DBG(DBG_CRYPT|DBG_CONTROL,
                static char buf[256]="<NULL>";

                if (c->alg_info_ike)
                    alg_info_snprint(buf, sizeof(buf)
                            , (struct alg_info *)c->alg_info_ike);
                DBG_log("ike string values: %s", buf);
            )
            if (c->alg_info_ike)
            {
                if (c->alg_info_ike->alg_info_cnt==0)
                    loglog(RC_LOG_SERIOUS
                           , "got 0 transforms for ike=\"%s\"", wm->ike);
            }
            else
            {
                loglog(RC_LOG_SERIOUS
                       , "ike string error: %s", ugh? ugh : "Unknown");
            }
        }
        
        c->sa_ike_life_seconds = wm->sa_ike_life_seconds;
        c->sa_ipsec_life_seconds = wm->sa_ipsec_life_seconds;
        c->sa_rekey_margin = wm->sa_rekey_margin;
        c->sa_rekey_fuzz = wm->sa_rekey_fuzz;
        c->sa_keying_tries = wm->sa_keying_tries;

        /* RFC 3706 DPD */
        c->dpd_delay = wm->dpd_delay;
        c->dpd_timeout = wm->dpd_timeout;
        c->dpd_action = wm->dpd_action;

        c->addr_family = wm->addr_family;
        c->tunnel_addr_family = wm->tunnel_addr_family;

        c->requested_ca = NULL;

        same_leftca  = extract_end(&c->spd.this, &wm->left, "left");
        same_rightca = extract_end(&c->spd.that, &wm->right, "right");

        if (same_rightca)
            c->spd.that.ca = c->spd.this.ca;
        else if (same_leftca)
            c->spd.this.ca = c->spd.that.ca;

        default_end(&c->spd.this, &c->spd.that.host_addr);
        default_end(&c->spd.that, &c->spd.this.host_addr);

        /* force any wildcard host IP address, any wildcard subnet
         * or any wildcard ID to that end
         */
        if (isanyaddr(&c->spd.this.host_addr) || c->spd.this.has_client_wildcard
        || c->spd.this.has_port_wildcard || c->spd.this.has_id_wildcards
        || c->spd.this.allow_any)
        {
            struct end t = c->spd.this;

            c->spd.this = c->spd.that;
            c->spd.that = t;
        }

        c->spd.next = NULL;
        c->spd.reqid = gen_reqid();

        /* set internal fields */
        c->instance_serial = 0;
        c->ac_next = connections;
        connections = c;
        c->interface = NULL;
        c->spd.routing = RT_UNROUTED;
        c->newest_isakmp_sa = SOS_NOBODY;
        c->newest_ipsec_sa = SOS_NOBODY;
        c->spd.eroute_owner = SOS_NOBODY;

        if (c->policy & POLICY_GROUP)
        {
            c->kind = CK_GROUP;
            add_group(c);
        }
        else if ((isanyaddr(&c->spd.that.host_addr) && !NEVER_NEGOTIATE(c->policy))
        || c->spd.that.has_client_wildcard || c->spd.that.has_port_wildcard
        || c->spd.that.has_id_wildcards || c->spd.that.allow_any)
        {
            /* Opportunistic or Road Warrior or wildcard client subnet
             * or wildcard ID */
            c->kind = CK_TEMPLATE;
        }
        else
        {
            c->kind = CK_PERMANENT;
        }
        set_policy_prio(c);     /* must be after kind is set */

#ifdef DEBUG
        c->extra_debugging = wm->debugging;
#endif

        c->gw_info = NULL;

        passert(!(wm->left.virt && wm->right.virt));
        if (wm->left.virt || wm->right.virt)
        {
            passert(isanyaddr(&c->spd.that.host_addr));
            c->spd.that.virt = create_virtual(c,
                wm->left.virt ? wm->left.virt : wm->right.virt);
            if (c->spd.that.virt)
                c->spd.that.has_client = TRUE;
        }

        unshare_connection_strings(c);
        (void)orient(c);

        if (c->ikev1)
            connect_to_host_pair(c);

        /* log all about this connection */
        plog("added connection description \"%s\"", c->name);
        DBG(DBG_CONTROL,
            char topo[CONNECTION_BUF];

            (void) format_connection(topo, sizeof(topo), c, &c->spd);

            DBG_log("%s", topo);

            /* Make sure that address families can be correctly inferred
             * from printed ends.
             */
            passert(c->addr_family == addrtypeof(&c->spd.this.host_addr)
                && c->addr_family == addrtypeof(&c->spd.this.host_nexthop)
                && (c->spd.this.has_client? c->tunnel_addr_family : c->addr_family)
                  == subnettypeof(&c->spd.this.client)

                && c->addr_family == addrtypeof(&c->spd.that.host_addr)
                && c->addr_family == addrtypeof(&c->spd.that.host_nexthop)
                && (c->spd.that.has_client? c->tunnel_addr_family : c->addr_family)
                  == subnettypeof(&c->spd.that.client));

            DBG_log("ike_life: %lus; ipsec_life: %lus; rekey_margin: %lus;"
                " rekey_fuzz: %lu%%; keyingtries: %lu; policy: %s"
                , (unsigned long) c->sa_ike_life_seconds
                , (unsigned long) c->sa_ipsec_life_seconds
                , (unsigned long) c->sa_rekey_margin
                , (unsigned long) c->sa_rekey_fuzz
                , (unsigned long) c->sa_keying_tries
                , prettypolicy(c->policy));
        );
    }
}

/* Derive a template connection from a group connection and target.
 * Similar to instantiate().  Happens at whack --listen.
 * Returns name of new connection.  May be NULL.
 * Caller is responsible for pfreeing.
 */
char *
add_group_instance(struct connection *group, const ip_subnet *target)
{
    char namebuf[100]
        , targetbuf[SUBNETTOT_BUF];
    struct connection *t;
    char *name = NULL;

    passert(group->kind == CK_GROUP);
    passert(oriented(*group));

    /* manufacture a unique name for this template */
    subnettot(target, 0, targetbuf, sizeof(targetbuf));
    snprintf(namebuf, sizeof(namebuf), "%s#%s", group->name, targetbuf);

    if (con_by_name(namebuf, FALSE) != NULL)
    {
        loglog(RC_DUPNAME, "group name + target yields duplicate name \"%s\""
            , namebuf);
    }
    else
    {
        t = clone_thing(*group, "group instance");
        t->name = namebuf;
        unshare_connection_strings(t);
        name = clone_str(t->name, "group instance name");
        t->spd.that.client = *target;
        t->policy &= ~(POLICY_GROUP | POLICY_GROUTED);
        t->kind = isanyaddr(&t->spd.that.host_addr) && !NEVER_NEGOTIATE(t->policy)
            ? CK_TEMPLATE : CK_INSTANCE;

        /* reset log file info */
        t->log_file_name = NULL;
        t->log_file = NULL;
        t->log_file_err = FALSE;

        t->spd.reqid = gen_reqid();

        if (t->spd.that.virt)
        {
            DBG_log("virtual_ip not supported in group instance");
            t->spd.that.virt = NULL;    
        }

        /* add to connections list */
        t->ac_next = connections;
        connections = t;

        /* same host_pair as parent: stick after parent on list */
        group->hp_next = t;

        /* route if group is routed */
        if (group->policy & POLICY_GROUTED)
        {
            if (!trap_connection(t))
                whack_log(RC_ROUTE, "could not route");
        }
    }
    return name;
}

/* an old target has disappeared for a group: delete instance */
void
remove_group_instance(const struct connection *group USED_BY_DEBUG
, const char *name)
{
    passert(group->kind == CK_GROUP);
    passert(oriented(*group));

    delete_connections_by_name(name, FALSE);
}

/* Common part of instantiating a Road Warrior or Opportunistic connection.
 * his_id can be used to carry over an ID discovered in Phase 1.
 * It must not disagree with the one in c, but if that is unspecified,
 * the new connection will use his_id.
 * If his_id is NULL, and c.that.id is uninstantiated (ID_NONE), the
 * new connection will continue to have an uninstantiated that.id.
 * Note: instantiation does not affect port numbers.
 *
 * Note that instantiate can only deal with a single SPD/eroute.
 */
static struct connection *
instantiate(struct connection *c, const ip_address *him
, u_int16_t his_port
, const struct id *his_id)
{
    struct connection *d;
    int wildcards;

    passert(c->kind == CK_TEMPLATE);
    passert(c->spd.next == NULL);

    c->instance_serial++;
    d = clone_thing(*c, "temporary connection");
    d->spd.that.allow_any = FALSE;

    if (his_id != NULL)
    {
        passert(match_id(his_id, &d->spd.that.id, &wildcards));
        d->spd.that.id = *his_id;
        d->spd.that.has_id_wildcards = FALSE;
    }
    unshare_connection_strings(d);
    unshare_ietfAttrList(&d->spd.this.groups);
    unshare_ietfAttrList(&d->spd.that.groups);
    d->kind = CK_INSTANCE;

    passert(oriented(*d));
    d->spd.that.host_addr = *him;
    setportof(htons(c->spd.that.port), &d->spd.that.host_addr);

    if (his_port) d->spd.that.host_port = his_port;

    default_end(&d->spd.that, &d->spd.this.host_addr);

    /* We cannot guess what our next_hop should be, but if it was
     * explicitly specified as 0.0.0.0, we set it to be him.
     * (whack will not allow nexthop to be elided in RW case.)
     */
    default_end(&d->spd.this, &d->spd.that.host_addr);
    d->spd.next = NULL;
    d->spd.reqid = gen_reqid();

    /* set internal fields */
    d->ac_next = connections;
    connections = d;
    d->spd.routing = RT_UNROUTED;
    d->newest_isakmp_sa = SOS_NOBODY;
    d->newest_ipsec_sa = SOS_NOBODY;
    d->spd.eroute_owner = SOS_NOBODY;

    /* reset log file info */
    d->log_file_name = NULL;
    d->log_file = NULL;
    d->log_file_err = FALSE;

    connect_to_host_pair(d);

    return d;
    if (sameaddr(&d->spd.that.host_addr, &d->spd.this.host_nexthop))
    {
        d->spd.this.host_nexthop = *him;
    }
}

struct connection *
rw_instantiate(struct connection *c, const ip_address *him, u_int16_t his_port
, const ip_subnet *his_net, const struct id *his_id)
{
    struct connection *d = instantiate(c, him, his_port, his_id);

    if (d && his_net && is_virtual_connection(c))
    {
        d->spd.that.client = *his_net;
        d->spd.that.virt = NULL;
        if (subnetishost(his_net) && addrinsubnet(him, his_net))
            d->spd.that.has_client = FALSE;
    }

    if (d->policy & POLICY_OPPO)
    {
        /* This must be before we know the client addresses.
         * Fill in one that is impossible.  This prevents anyone else from
         * trying to use this connection to get to a particular client
         */
        d->spd.that.client = *aftoinfo(subnettypeof(&d->spd.that.client))->none;
    }
    DBG(DBG_CONTROL
        , DBG_log("instantiated \"%s\" for %s" , d->name, ip_str(him)));
    return d;
}

struct connection *
oppo_instantiate(struct connection *c
, const ip_address *him
, const struct id *his_id
, struct gw_info *gw
, const ip_address *our_client USED_BY_DEBUG
, const ip_address *peer_client)
{
    struct connection *d = instantiate(c, him, 0, his_id);

    passert(d->spd.next == NULL);

    /* fill in our client side */
    if (d->spd.this.has_client)
    {
        /* there was a client in the abstract connection
         * so we demand that the required client is within that subnet.
         */
        passert(addrinsubnet(our_client, &d->spd.this.client));
        happy(addrtosubnet(our_client, &d->spd.this.client));
        /* opportunistic connections do not use port selectors */
        setportof(0, &d->spd.this.client.addr);
    }
    else
    {
        /* there was no client in the abstract connection
         * so we demand that the required client be the host
         */
        passert(sameaddr(our_client, &d->spd.this.host_addr));
    }

    /* fill in peer's client side.
     * If the client is the peer, excise the client from the connection.
     */
    passert((d->policy & POLICY_OPPO)
        && addrinsubnet(peer_client, &d->spd.that.client));
    happy(addrtosubnet(peer_client, &d->spd.that.client));
    /* opportunistic connections do not use port selectors */
    setportof(0, &d->spd.that.client.addr);

    if (sameaddr(peer_client, &d->spd.that.host_addr))
        d->spd.that.has_client = FALSE;

    passert(d->gw_info == NULL);
    gw_addref(gw);
    d->gw_info = gw;

    /* Adjust routing if something is eclipsing c.
     * It must be a %hold for us (hard to passert this).
     * If there was another instance eclipsing, we'd be using it.
     */
    if (c->spd.routing == RT_ROUTED_ECLIPSED)
        d->spd.routing = RT_ROUTED_PROSPECTIVE;

    /* Remember if the template is routed:
     * if so, this instance applies for initiation
     * even if it is created for responding.
     */
    if (routed(c->spd.routing))
        d->instance_initiation_ok = TRUE;

    DBG(DBG_CONTROL,
        char topo[CONNECTION_BUF];

        (void) format_connection(topo, sizeof(topo), d, &d->spd);
        DBG_log("instantiated \"%s\": %s", d->name, topo);
    );
    return d;
}

/* priority formatting */
void
fmt_policy_prio(policy_prio_t pp, char buf[POLICY_PRIO_BUF])
{
    if (pp == BOTTOM_PRIO)
        snprintf(buf, POLICY_PRIO_BUF, "0");
    else
        snprintf(buf, POLICY_PRIO_BUF, "%lu,%lu"
            , pp>>16, (pp & ~(~(policy_prio_t)0 << 16)) >> 8);
}

/* Format any information needed to identify an instance of a connection.
 * Fills any needed information into buf which MUST be big enough.
 * Road Warrior: peer's IP address
 * Opportunistic: [" " myclient "==="] " ..." peer ["===" hisclient] '\0'
 */
static size_t
fmt_client(const ip_subnet *client, const ip_address *gw, const char *prefix, char buf[ADDRTOT_BUF])
{
    if (subnetisaddr(client, gw))
    {
        buf[0] = '\0';  /* compact denotation for "self" */
    }
    else
    {
        char *ap;

        strcpy(buf, prefix);
        ap = buf + strlen(prefix);
        if (subnetisnone(client))
            strcpy(ap, "?");    /* unknown */
        else
            subnettot(client, 0, ap, SUBNETTOT_BUF);
    }
    return strlen(buf);
}

void
fmt_conn_instance(const struct connection *c, char buf[CONN_INST_BUF])
{
    char *p = buf;

    *p = '\0';

    if (c->kind == CK_INSTANCE)
    {
        if (c->instance_serial != 0)
        {
            snprintf(p, CONN_INST_BUF, "[%lu]", c->instance_serial);
            p += strlen(p);
        }

        if (c->policy & POLICY_OPPO)
        {
            size_t w = fmt_client(&c->spd.this.client, &c->spd.this.host_addr, " ", p);

            p += w;

            strcpy(p, w == 0? " ..." : "=== ...");
            p += strlen(p);

            addrtot(&c->spd.that.host_addr, 0, p, ADDRTOT_BUF);
            p += strlen(p);

            (void) fmt_client(&c->spd.that.client, &c->spd.that.host_addr, "===", p);
        }
        else
        {
            *p++ = ' ';
            addrtot(&c->spd.that.host_addr, 0, p, ADDRTOT_BUF);
#
            if (c->spd.that.host_port != pluto_port)
            {
                p += strlen(p);
                sprintf(p, ":%d", c->spd.that.host_port);
            }
        }
    }
}

/* Find an existing connection for a trapped outbound packet.
 * This is attempted before we bother with gateway discovery.
 *   + this connection is routed or instance_of_routed_template
 *     (i.e. approved for on-demand)
 *   + this subnet contains our_client (or we are our_client)
 *   + that subnet contains peer_client (or peer is peer_client)
 *   + don't care about Phase 1 IDs (we don't know)
 * Note: result may still need to be instantiated.
 * The winner has the highest policy priority.
 *
 * If there are several with that priority, we give preference to
 * the first one that is an instance.
 *
 * See also build_outgoing_opportunistic_connection.
 */
struct connection *
find_connection_for_clients(struct spd_route **srp,
                            const ip_address *our_client,
                            const ip_address *peer_client,
                            int transport_proto)
{
    struct connection *c = connections, *best = NULL;
    policy_prio_t best_prio = BOTTOM_PRIO;
    struct spd_route *sr;
    struct spd_route *best_sr = NULL;
    int our_port  = ntohs(portof(our_client));
    int peer_port = ntohs(portof(peer_client));

    passert(!isanyaddr(our_client) && !isanyaddr(peer_client));
#ifdef DEBUG
    if (DBGP(DBG_CONTROL))
    {
        char ocb[ADDRTOT_BUF], pcb[ADDRTOT_BUF];

        addrtot(our_client, 0, ocb, sizeof(ocb));
        addrtot(peer_client, 0, pcb, sizeof(pcb));
        DBG_log("find_connection: "
                "looking for policy for connection: %s:%d/%d -> %s:%d/%d"
                , ocb, transport_proto, our_port, pcb, transport_proto, peer_port);
    }
#endif /* DEBUG */

    for (c = connections; c != NULL; c = c->ac_next)
    {
        if (c->kind == CK_GROUP)
            continue;

        for (sr = &c->spd; best!=c && sr; sr = sr->next)
        {
            if ((routed(sr->routing) || c->instance_initiation_ok)
            && addrinsubnet(our_client, &sr->this.client)
            && addrinsubnet(peer_client, &sr->that.client)
            && addrinsubnet(peer_client, &sr->that.client)
            && (!sr->this.protocol || transport_proto == sr->this.protocol)
            && (!sr->this.port || our_port == sr->this.port)
            && (!sr->that.port || peer_port == sr->that.port))
            {
                char cib[CONN_INST_BUF];
                char cib2[CONN_INST_BUF];

                policy_prio_t prio = 8 * (c->prio + (c->kind == CK_INSTANCE))
                                   + 2 * (sr->this.port == our_port)
                                   + 2 * (sr->that.port == peer_port)
                                   +     (sr->this.protocol == transport_proto);

#ifdef DEBUG
                if (DBGP(DBG_CONTROL|DBG_CONTROLMORE))
                {
                    char c_ocb[SUBNETTOT_BUF], c_pcb[SUBNETTOT_BUF];

                    subnettot(&c->spd.this.client, 0, c_ocb, sizeof(c_ocb));
                    subnettot(&c->spd.that.client, 0, c_pcb, sizeof(c_pcb));
                    DBG_log("find_connection: conn \"%s\"%s has compatible peers: %s->%s [pri: %ld]"
                            , c->name
                            , (fmt_conn_instance(c, cib), cib)
                            , c_ocb, c_pcb, prio);
                }
#endif /* DEBUG */

                if (best == NULL)
                {
                    best = c;
                    best_sr = sr;
                    best_prio = prio;
                }

                DBG(DBG_CONTROLMORE,
                    DBG_log("find_connection: "
                            "comparing best \"%s\"%s [pri:%ld]{%p} (child %s) to \"%s\"%s [pri:%ld]{%p} (child %s)"
                            , best->name
                            , (fmt_conn_instance(best, cib), cib)
                            , best_prio
                            , best
                            , (best->policy_next ? best->policy_next->name : "none")
                            , c->name
                            , (fmt_conn_instance(c, cib2), cib2)
                            , prio
                            , c
                            , (c->policy_next ? c->policy_next->name : "none")));

                if (prio > best_prio)
                {
                    best = c;
                    best_sr = sr;
                    best_prio = prio;
                }
            }
        }
    }

    if (best!= NULL && NEVER_NEGOTIATE(best->policy))
        best = NULL;

    if (srp != NULL && best != NULL)
        *srp = best_sr;

#ifdef DEBUG
    if (DBGP(DBG_CONTROL))
    {
        if (best)
        {
            char cib[CONN_INST_BUF];
            DBG_log("find_connection: concluding with \"%s\"%s [pri:%ld]{%p} kind=%s"
                    , best->name
                    , (fmt_conn_instance(best, cib), cib)
                    , best_prio
                    , best
                    , enum_name(&connection_kind_names, best->kind));
        } else {
            DBG_log("find_connection: concluding with empty");
        }
    }
#endif /* DEBUG */

    return best;
}

/* Find and instantiate a connection for an outgoing Opportunistic connection.
 * We've already discovered its gateway.
 * We look for a the connection such that:
 *   + this is one of our interfaces
 *   + this subnet contains our_client (or we are our_client)
 *     (we will specialize the client).  We prefer the smallest such subnet.
 *   + that subnet contains peer_clent (we will specialize the client).
 *     We prefer the smallest such subnet.
 *   + is opportunistic
 *   + that peer is NO_IP
 *   + don't care about Phase 1 IDs (probably should be default)
 * We could look for a connection that already had the desired peer
 * (rather than NO_IP) specified, but it doesn't seem worth the
 * bother.
 *
 * We look for the routed policy applying to the narrowest subnets.
 * We only succeed if we find such a policy AND it is satisfactory.
 *
 * The body of the inner loop is a lot like that in
 * find_connection_for_clients.  In this case, we know the gateways
 * that we need to instantiate an opportunistic connection.
 */
struct connection *
build_outgoing_opportunistic_connection(struct gw_info *gw
                                        ,const ip_address *our_client
                                        ,const ip_address *peer_client)
{
    struct iface *p;
    struct connection *best = NULL;
    struct spd_route *sr, *bestsr;
    char ocb[ADDRTOT_BUF], pcb[ADDRTOT_BUF];

    addrtot(our_client, 0, ocb, sizeof(ocb));
    addrtot(peer_client, 0, pcb, sizeof(pcb));

    passert(!isanyaddr(our_client) && !isanyaddr(peer_client));

    /* We don't know his ID yet, so gw id must be an ipaddr */
    passert(gw->key != NULL);
    passert(id_is_ipaddr(&gw->gw_id));

    /* for each of our addresses... */
    for (p = interfaces; p != NULL; p = p->next)
    {
        /* go through those connections with our address and NO_IP as hosts
         * We cannot know what port the peer would use, so we assume
         * that it is pluto_port (makes debugging easier).
         */
        struct connection *c = find_host_pair_connections(&p->addr
            , pluto_port, (ip_address *)NULL, pluto_port);

        for (; c != NULL; c = c->hp_next)
        {
            DBG(DBG_OPPO,
                DBG_log("checking %s", c->name));
            if (c->kind == CK_GROUP)
            {
                continue;
            }

            for (sr = &c->spd; best!=c && sr; sr = sr->next)
            {
                if (routed(sr->routing)
                && addrinsubnet(our_client, &sr->this.client)
                && addrinsubnet(peer_client, &sr->that.client))
                {
                    if (best == NULL)
                    {
                        best = c;
                        break;
                    }

                    DBG(DBG_OPPO,
                        DBG_log("comparing best %s to %s"
                                , best->name, c->name));

                    for (bestsr = &best->spd; best!=c && bestsr; bestsr=bestsr->next)
                    {
                        if (!subnetinsubnet(&bestsr->this.client, &sr->this.client)
                        || (samesubnet(&bestsr->this.client, &sr->this.client)
                             && !subnetinsubnet(&bestsr->that.client
                                                , &sr->that.client)))
                        {
                            best = c;
                        }
                    }
                }
            }
        }
    }

    if (best == NULL
    || NEVER_NEGOTIATE(best->policy)
    || (best->policy & POLICY_OPPO) == LEMPTY
    || best->kind != CK_TEMPLATE)
        return NULL;
    else
        return oppo_instantiate(best, &gw->gw_id.ip_addr, NULL, gw
                              , our_client, peer_client);
}

bool
orient(struct connection *c)
{
    struct spd_route *sr;

    if (!oriented(*c))
    {
        struct iface *p;

        for (sr = &c->spd; sr; sr = sr->next)
        {
            /* Note: this loop does not stop when it finds a match:
             * it continues checking to catch any ambiguity.
             */
            for (p = interfaces; p != NULL; p = p->next)
            {
                if (p->ike_float)
                    continue;

                for (;;)
                {
                    /* check if this interface matches this end */
                    if (sameaddr(&sr->this.host_addr, &p->addr)
                    && (!no_klips || sr->this.host_port == pluto_port))
                    {
                        if (oriented(*c))
                        {
                            if (c->interface == p)
                                loglog(RC_LOG_SERIOUS
                                       , "both sides of \"%s\" are our interface %s!"
                                       , c->name, p->rname);
                            else
                                loglog(RC_LOG_SERIOUS, "two interfaces match \"%s\" (%s, %s)"
                                       , c->name, c->interface->rname, p->rname);
                            c->interface = NULL;        /* withdraw orientation */
                            return FALSE;
                        }
                        c->interface = p;
                    }

                    /* done with this interface if it doesn't match that end */
                    if (!(sameaddr(&sr->that.host_addr, &p->addr)
                    && (!no_klips || sr->that.host_port == pluto_port)))
                        break;

                    /* swap ends and try again.
                     * It is a little tricky to see that this loop will stop.
                     * Only continue if the far side matches.
                     * If both sides match, there is an error-out.
                     */
                    {
                        struct end t = sr->this;

                        sr->this = sr->that;
                        sr->that = t;
                    }
                }
            }
        }
    }
    return oriented(*c);
}

void
initiate_connection(const char *name, int whackfd)
{
    struct connection *c = con_by_name(name, TRUE);

    if (c != NULL && c->ikev1)
    {
        set_cur_connection(c);
        if (!oriented(*c))
        {
            loglog(RC_ORIENT, "we have no ipsecN interface for either end of this connection");
        }
        else if (NEVER_NEGOTIATE(c->policy))
        {
            loglog(RC_INITSHUNT
                , "cannot initiate an authby=never connection");
        }
        else if (c->kind != CK_PERMANENT && !c->spd.that.allow_any)
        {
            if (isanyaddr(&c->spd.that.host_addr))
                loglog(RC_NOPEERIP, "cannot initiate connection without knowing peer IP address");
            else
                loglog(RC_WILDCARD, "cannot initiate connection with ID wildcards");
        }
        else
        {
            /* do we have to prompt for a PIN code? */
            if (c->spd.this.sc != NULL && !c->spd.this.sc->valid && whackfd != NULL_FD)
            {
                scx_get_pin(c->spd.this.sc, whackfd);
            }
            if (c->spd.this.sc != NULL && !c->spd.this.sc->valid)
            {
                loglog(RC_NOVALIDPIN, "cannot initiate connection without valid PIN");
            }
            else
            {

                if (c->spd.that.allow_any)
                {
                    c = instantiate(c, &c->spd.that.host_addr, c->spd.that.host_port
                                  , &c->spd.that.id);
                }

                /* We will only request an IPsec SA if policy isn't empty
                 * (ignoring Main Mode items).
                 * This is a fudge, but not yet important.
                 * If we are to proceed asynchronously, whackfd will be NULL_FD.
                 */
                c->policy |= POLICY_UP;
                ipsecdoi_initiate(whackfd, c, c->policy, 1, SOS_NOBODY);
                whackfd = NULL_FD;      /* protect from close */
            }
        }
        reset_cur_connection();
    }
    close_any(whackfd);
}

/* (Possibly) Opportunistic Initiation:
 * Knowing clients (single IP addresses), try to build an tunnel.
 * This may involve discovering a gateway and instantiating an
 * Opportunistic connection.  Called when a packet is caught by
 * a %trap, or when whack --oppohere --oppothere is used.
 * It may turn out that an existing or non-opporunistic connnection
 * can handle the traffic.
 *
 * Most of the code will be restarted if an ADNS request is made
 * to discover the gateway.  The only difference between the first
 * and second entry is whether gateways_from_dns is NULL or not.
 *      initiate_opportunistic: initial entrypoint
 *      continue_oppo: where we pickup when ADNS result arrives
 *      initiate_opportunistic_body: main body shared by above routines
 *      cannot_oppo: a helper function to log a diagnostic
 * This structure repeats a lot of code when the ADNS result arrives.
 * This seems like a waste, but anything learned the first time through
 * may no longer be true!
 *
 * After the first IKE message is sent, the regular state machinery
 * carries negotiation forward.
 */

enum find_oppo_step {
    fos_start,
    fos_myid_ip_txt,
    fos_myid_hostname_txt,
    fos_myid_ip_key,
    fos_myid_hostname_key,
    fos_our_client,
    fos_our_txt,
#ifdef USE_KEYRR
    fos_our_key,
#endif /* USE_KEYRR */
    fos_his_client,
    fos_done
};

#ifdef DEBUG
static const char *const oppo_step_name[] = {
    "fos_start",
    "fos_myid_ip_txt",
    "fos_myid_hostname_txt",
    "fos_myid_ip_key",
    "fos_myid_hostname_key",
    "fos_our_client",
    "fos_our_txt",
#ifdef USE_KEYRR
    "fos_our_key",
#endif /* USE_KEYRR */
    "fos_his_client",
    "fos_done"
};
#endif /* DEBUG */

struct find_oppo_bundle {
    enum find_oppo_step step;
    err_t want;
    bool failure_ok;            /* if true, continue_oppo should not die on DNS failure */
    ip_address our_client;      /* not pointer! */
    ip_address peer_client;
    int transport_proto;
    bool held;
    policy_prio_t policy_prio;
    ipsec_spi_t failure_shunt;  /* in host order!  0 for delete. */
    int whackfd;
};

struct find_oppo_continuation {
    struct adns_continuation ac;        /* common prefix */
    struct find_oppo_bundle b;
};

static void
cannot_oppo(struct connection *c
            , struct find_oppo_bundle *b
            , err_t ugh)
{
    char pcb[ADDRTOT_BUF];
    char ocb[ADDRTOT_BUF];

    addrtot(&b->peer_client, 0, pcb, sizeof(pcb));
    addrtot(&b->our_client, 0, ocb, sizeof(ocb));

    DBG(DBG_DNS | DBG_OPPO, DBG_log("Can't Opportunistically initiate for %s to %s: %s"
        , ocb, pcb, ugh));

    whack_log(RC_OPPOFAILURE
        , "Can't Opportunistically initiate for %s to %s: %s"
        , ocb, pcb, ugh);

    if (c != NULL && c->policy_next != NULL)
    {
        /* there is some policy that comes afterwards */
        struct spd_route *shunt_spd;
        struct connection *nc = c->policy_next;
        struct state *st;

        passert(c->kind == CK_TEMPLATE);
        passert(c->policy_next->kind == CK_PERMANENT);

        DBG(DBG_OPPO, DBG_log("OE failed for %s to %s, but %s overrides shunt"
                              , ocb, pcb, c->policy_next->name));

        /*
         * okay, here we need add to the "next" policy, which is ought
         * to be an instance.
         * We will add another entry to the spd_route list for the specific
         * situation that we have.
         */

        shunt_spd = clone_thing(nc->spd, "shunt eroute policy");

        shunt_spd->next = nc->spd.next;
        nc->spd.next = shunt_spd;

        happy(addrtosubnet(&b->peer_client, &shunt_spd->that.client));

        if (sameaddr(&b->peer_client, &shunt_spd->that.host_addr))
            shunt_spd->that.has_client = FALSE;

        /*
         * override the tunnel destination with the one from the secondaried
         * policy
         */
        shunt_spd->that.host_addr = nc->spd.that.host_addr;

        /* now, lookup the state, and poke it up.
         */

        st = state_with_serialno(nc->newest_ipsec_sa);

        /* XXX what to do if the IPSEC SA has died? */
        passert(st != NULL);

        /* link the new connection instance to the state's list of
         * connections
         */

        DBG(DBG_OPPO, DBG_log("installing state: %ld for %s to %s"
                              , nc->newest_ipsec_sa
                              , ocb, pcb));

#ifdef DEBUG
        if (DBGP(DBG_OPPO | DBG_CONTROLMORE))
        {
            char state_buf[LOG_WIDTH];
            char state_buf2[LOG_WIDTH];
            time_t n = now();

            fmt_state(FALSE, st, n
                      , state_buf, sizeof(state_buf)
                      , state_buf2, sizeof(state_buf2));
            DBG_log("cannot_oppo, failure SA1: %s", state_buf);
            DBG_log("cannot_oppo, failure SA2: %s", state_buf2);
        }
#endif /* DEBUG */

        if (!route_and_eroute(c, shunt_spd, st))
        {
            whack_log(RC_OPPOFAILURE
                      , "failed to instantiate shunt policy %s for %s to %s"
                      , c->name
                      , ocb, pcb);
        }
        return;
    }

#ifdef KLIPS
    if (b->held)
    {
        /* Replace HOLD with b->failure_shunt.
         * If no b->failure_shunt specified, use SPI_PASS -- THIS MAY CHANGE.
         */
        if (b->failure_shunt == 0)
        {
            DBG(DBG_OPPO, DBG_log("no explicit failure shunt for %s to %s; installing %%pass"
                                  , ocb, pcb));
        }

        (void) replace_bare_shunt(&b->our_client, &b->peer_client
            , b->policy_prio
            , b->failure_shunt
            , b->failure_shunt != 0
            , b->transport_proto
            , ugh);
    }
#endif
}

static void initiate_opportunistic_body(struct find_oppo_bundle *b
    , struct adns_continuation *ac, err_t ac_ugh);      /* forward */

void
initiate_opportunistic(const ip_address *our_client
, const ip_address *peer_client
, int transport_proto
, bool held
, int whackfd)
{
    struct find_oppo_bundle b;

    b.want = (whackfd == NULL_FD ? "whack" : "acquire");
    b.failure_ok = FALSE;
    b.our_client = *our_client;
    b.peer_client = *peer_client;
    b.transport_proto = transport_proto;
    b.held = held;
    b.policy_prio = BOTTOM_PRIO;
    b.failure_shunt = 0;
    b.whackfd = whackfd;
    b.step = fos_start;
    initiate_opportunistic_body(&b, NULL, NULL);
}

static void
continue_oppo(struct adns_continuation *acr, err_t ugh)
{
    struct find_oppo_continuation *cr = (void *)acr;    /* inherit, damn you! */
    struct connection *c;
    bool was_held = cr->b.held;
    int whackfd = cr->b.whackfd;

    /* note: cr->id has no resources; cr->sgw_id is id_none:
     * neither need freeing.
     */
    whack_log_fd = whackfd;

#ifdef KLIPS
    /* Discover and record whether %hold has gone away.
     * This could have happened while we were awaiting DNS.
     * We must check BEFORE any call to cannot_oppo.
     */
    if (was_held)
        cr->b.held = has_bare_hold(&cr->b.our_client, &cr->b.peer_client
            , cr->b.transport_proto);
#endif

#ifdef DEBUG
    /* if we're going to ignore the error, at least note it in debugging log */
    if (cr->b.failure_ok && ugh != NULL)
    {
        DBG(DBG_CONTROL | DBG_DNS,
            {
                char ocb[ADDRTOT_BUF];
                char pcb[ADDRTOT_BUF];

                addrtot(&cr->b.our_client, 0, ocb, sizeof(ocb));
                addrtot(&cr->b.peer_client, 0, pcb, sizeof(pcb));
                DBG_log("continuing from failed DNS lookup for %s, %s to %s: %s"
                    , cr->b.want, ocb, pcb, ugh);
            });
    }
#endif

    if (!cr->b.failure_ok && ugh != NULL)
    {
        c = find_connection_for_clients(NULL, &cr->b.our_client, &cr->b.peer_client
            , cr->b.transport_proto);
        cannot_oppo(c, &cr->b
                    , builddiag("%s: %s", cr->b.want, ugh));
    }
    else if (was_held && !cr->b.held)
    {
        /* was_held indicates we were started due to a %trap firing
         * (as opposed to a "whack --oppohere --oppothere").
         * Since the %hold has gone, we can assume that somebody else
         * has beaten us to the punch.  We can go home.  But lets log it.
         */
        char ocb[ADDRTOT_BUF];
        char pcb[ADDRTOT_BUF];

        addrtot(&cr->b.our_client, 0, ocb, sizeof(ocb));
        addrtot(&cr->b.peer_client, 0, pcb, sizeof(pcb));

        loglog(RC_COMMENT
            , "%%hold otherwise handled during DNS lookup for Opportunistic Initiation for %s to %s"
            , ocb, pcb);
    }
    else
    {
        initiate_opportunistic_body(&cr->b, &cr->ac, ugh);
        whackfd = NULL_FD;      /* was handed off */
    }

    whack_log_fd = NULL_FD;
    close_any(whackfd);
}

#ifdef USE_KEYRR
static err_t
check_key_recs(enum myid_state try_state
, const struct connection *c
, struct adns_continuation *ac)
{
    /* Check if KEY lookup yielded good results.
     * Looking up based on our ID.  Used if
     * client is ourself, or if TXT had no public key.
     * Note: if c is different this time, there is
     * a chance that we did the wrong query.
     * If so, treat as a kind of failure.
     */
    enum myid_state old_myid_state = myid_state;
    const struct RSA_private_key *our_RSA_pri;
    err_t ugh = NULL;

    myid_state = try_state;

    if (old_myid_state != myid_state
    && old_myid_state == MYID_SPECIFIED)
    {
        ugh = "%myid was specified while we were guessing";
    }
    else if ((our_RSA_pri = get_RSA_private_key(c)) == NULL)
    {
        ugh = "we don't know our own RSA key";
    }
    else if (!same_id(&ac->id, &c->spd.this.id))
    {
        ugh = "our ID changed underfoot";
    }
    else
    {
        /* Similar to code in RSA_check_signature
         * for checking the other side.
         */
        pubkey_list_t *kr;

        ugh = "no KEY RR found for us";
        for (kr = ac->keys_from_dns; kr != NULL; kr = kr->next)
        {
            ugh = "all our KEY RRs have the wrong public key";
            if (kr->key->alg == PUBKEY_ALG_RSA
            && same_RSA_public_key(&our_RSA_pri->pub, &kr->key->u.rsa))
            {
                ugh = NULL;     /* good! */
                break;
            }
        }
    }
    if (ugh != NULL)
        myid_state = old_myid_state;
    return ugh;
}
#endif /* USE_KEYRR */

static err_t
check_txt_recs(enum myid_state try_state
, const struct connection *c
, struct adns_continuation *ac)
{
    /* Check if TXT lookup yielded good results.
     * Looking up based on our ID.  Used if
     * client is ourself, or if TXT had no public key.
     * Note: if c is different this time, there is
     * a chance that we did the wrong query.
     * If so, treat as a kind of failure.
     */
    enum myid_state old_myid_state = myid_state;
    const struct RSA_private_key *our_RSA_pri;
    err_t ugh = NULL;

    myid_state = try_state;

    if (old_myid_state != myid_state
    && old_myid_state == MYID_SPECIFIED)
    {
        ugh = "%myid was specified while we were guessing";
    }
    else if ((our_RSA_pri = get_RSA_private_key(c)) == NULL)
    {
        ugh = "we don't know our own RSA key";
    }
    else if (!same_id(&ac->id, &c->spd.this.id))
    {
        ugh = "our ID changed underfoot";
    }
    else
    {
        /* Similar to code in RSA_check_signature
         * for checking the other side.
         */
        struct gw_info *gwp;

        ugh = "no TXT RR found for us";
        for (gwp = ac->gateways_from_dns; gwp != NULL; gwp = gwp->next)
        {
            ugh = "all our TXT RRs have the wrong public key";
            if (gwp->key->alg == PUBKEY_ALG_RSA
            && same_RSA_public_key(&our_RSA_pri->pub, &gwp->key->u.rsa))
            {
                ugh = NULL;     /* good! */
                break;
            }
        }
    }
    if (ugh != NULL)
        myid_state = old_myid_state;
    return ugh;
}


/* note: gateways_from_dns must be NULL iff this is the first call */
static void
initiate_opportunistic_body(struct find_oppo_bundle *b
, struct adns_continuation *ac
, err_t ac_ugh)
{
    struct connection *c;
    struct spd_route *sr;

    /* What connection shall we use?
     * First try for one that explicitly handles the clients.
     */
    DBG(DBG_CONTROL,
        {
            char ours[ADDRTOT_BUF];
            char his[ADDRTOT_BUF];
            int ourport;
            int hisport;

            addrtot(&b->our_client, 0, ours, sizeof(ours));
            addrtot(&b->peer_client, 0, his, sizeof(his));
            ourport = ntohs(portof(&b->our_client));
            hisport = ntohs(portof(&b->peer_client));
            DBG_log("initiate on demand from %s:%d to %s:%d proto=%d state: %s because: %s"
                , ours, ourport, his, hisport, b->transport_proto
                , oppo_step_name[b->step], b->want);
        });
    if (isanyaddr(&b->our_client) || isanyaddr(&b->peer_client))
    {
        cannot_oppo(NULL, b, "impossible IP address");
    }
    else if ((c = find_connection_for_clients(&sr
                                              , &b->our_client
                                              , &b->peer_client
                                              , b->transport_proto)) == NULL)
    {
        /* No connection explicitly handles the clients and there
         * are no Opportunistic connections -- whine and give up.
         * The failure policy cannot be gotten from a connection; we pick %pass.
         */
        cannot_oppo(NULL, b, "no routed Opportunistic template covers this pair");
    }
    else if (c->kind != CK_TEMPLATE)
    {
        /* We've found a connection that can serve.
         * Do we have to initiate it?
         * Not if there is currently an IPSEC SA.
         * But if there is an IPSEC SA, then KLIPS would not
         * have generated the acquire.  So we assume that there isn't one.
         * This may be redundant if a non-opportunistic
         * negotiation is already being attempted.
         */

        /* If we are to proceed asynchronously, b->whackfd will be NULL_FD. */

        if(c->kind == CK_INSTANCE)
        {
            char cib[CONN_INST_BUF];
            /* there is already an instance being negotiated, no nothing */
            DBG(DBG_CONTROL, DBG_log("found existing instance \"%s\"%s, rekeying it"
                                     , c->name
                                     , (fmt_conn_instance(c, cib), cib)));
            /* XXX-mcr - return; */
        }

        /* otherwise, there is some kind of static conn that can handle
         * this connection, so we initiate it */

#ifdef KLIPS
        if (b->held)
        {
            /* what should we do on failure? */
            (void) assign_hold(c, sr, b->transport_proto, &b->our_client, &b->peer_client);
        }
#endif
        ipsecdoi_initiate(b->whackfd, c, c->policy, 1, SOS_NOBODY);
        b->whackfd = NULL_FD;   /* protect from close */
    }
    else
    {
        /* We are handling an opportunistic situation.
         * This involves several DNS lookup steps that require suspension.
         * Note: many facts might change while we're suspended.
         * Here be dragons.
         *
         * The first chunk of code handles the result of the previous
         * DNS query (if any).  It also selects the kind of the next step.
         * The second chunk initiates the next DNS query (if any).
         */
        enum find_oppo_step next_step;
        err_t ugh = ac_ugh;
        char mycredentialstr[BUF_LEN];
        char cib[CONN_INST_BUF];

        DBG(DBG_CONTROL, DBG_log("creating new instance from \"%s\"%s"
                                 , c->name
                                 , (fmt_conn_instance(c, cib), cib)));
                                 

        idtoa(&sr->this.id, mycredentialstr, sizeof(mycredentialstr));

        passert(c->policy & POLICY_OPPO);   /* can't initiate Road Warrior connections */

        /* handle any DNS answer; select next step */

        switch (b->step)
        {
        case fos_start:
            /* just starting out: select first query step */
            next_step = fos_myid_ip_txt;
            break;

        case fos_myid_ip_txt:   /* TXT for our default IP address as %myid */
            ugh = check_txt_recs(MYID_IP, c, ac);
            if (ugh != NULL)
            {
                /* cannot use our IP as OE identitiy for initiation */
                DBG(DBG_OPPO, DBG_log("can not use our IP (%s:TXT) as identity: %s"
                                      , myid_str[MYID_IP]
                                      , ugh));
                if (!logged_myid_ip_txt_warning)
                {
                    loglog(RC_LOG_SERIOUS
                           , "can not use our IP (%s:TXT) as identity: %s"
                           , myid_str[MYID_IP]
                           , ugh);
                    logged_myid_ip_txt_warning = TRUE;
                }

                next_step = fos_myid_hostname_txt;
                ugh = NULL;     /* failure can be recovered from */
            }
            else
            {
                /* we can use our IP as OE identity for initiation */
                if (!logged_myid_ip_txt_warning)
                {
                    loglog(RC_LOG_SERIOUS
                           , "using our IP (%s:TXT) as identity!"
                           , myid_str[MYID_IP]);
                    logged_myid_ip_txt_warning = TRUE;
                }

                next_step = fos_our_client;
            }
            break;

        case fos_myid_hostname_txt:     /* TXT for our hostname as %myid */
            ugh = check_txt_recs(MYID_HOSTNAME, c, ac);
            if (ugh != NULL)
            {
                /* cannot use our hostname as OE identitiy for initiation */
                DBG(DBG_OPPO, DBG_log("can not use our hostname (%s:TXT) as identity: %s"
                                      , myid_str[MYID_HOSTNAME]
                                      , ugh));
                if (!logged_myid_fqdn_txt_warning)
                {
                    loglog(RC_LOG_SERIOUS
                           , "can not use our hostname (%s:TXT) as identity: %s"
                           , myid_str[MYID_HOSTNAME]
                           , ugh);
                    logged_myid_fqdn_txt_warning = TRUE;
                }
#ifdef USE_KEYRR
                next_step = fos_myid_ip_key;
                ugh = NULL;     /* failure can be recovered from */
#endif
            }
            else
            {
                /* we can use our hostname as OE identity for initiation */
                if (!logged_myid_fqdn_txt_warning)
                {
                    loglog(RC_LOG_SERIOUS
                           , "using our hostname (%s:TXT) as identity!"
                           , myid_str[MYID_HOSTNAME]);
                    logged_myid_fqdn_txt_warning = TRUE;
                }
                next_step = fos_our_client;
            }
            break;

#ifdef USE_KEYRR
        case fos_myid_ip_key:   /* KEY for our default IP address as %myid */
            ugh = check_key_recs(MYID_IP, c, ac);
            if (ugh != NULL)
            {
                /* cannot use our IP as OE identitiy for initiation */
                DBG(DBG_OPPO, DBG_log("can not use our IP (%s:KEY) as identity: %s"
                                      , myid_str[MYID_IP]
                                      , ugh));
                if (!logged_myid_ip_key_warning)
                {
                    loglog(RC_LOG_SERIOUS
                           , "can not use our IP (%s:KEY) as identity: %s"
                           , myid_str[MYID_IP]
                           , ugh);
                    logged_myid_ip_key_warning = TRUE;
                }

                next_step = fos_myid_hostname_key;
                ugh = NULL;     /* failure can be recovered from */
            }
            else
            {
                /* we can use our IP as OE identity for initiation */
                if (!logged_myid_ip_key_warning)
                {
                    loglog(RC_LOG_SERIOUS
                           , "using our IP (%s:KEY) as identity!"
                           , myid_str[MYID_IP]);
                    logged_myid_ip_key_warning = TRUE;
                }
                next_step = fos_our_client;
            }
            break;

        case fos_myid_hostname_key:     /* KEY for our hostname as %myid */
            ugh = check_key_recs(MYID_HOSTNAME, c, ac);
            if (ugh != NULL)
            {
                /* cannot use our IP as OE identitiy for initiation */
                DBG(DBG_OPPO, DBG_log("can not use our hostname (%s:KEY) as identity: %s"
                                      , myid_str[MYID_HOSTNAME]
                                      , ugh));
                if (!logged_myid_fqdn_key_warning)
                {
                    loglog(RC_LOG_SERIOUS
                           , "can not use our hostname (%s:KEY) as identity: %s"
                           , myid_str[MYID_HOSTNAME]
                           , ugh);
                    logged_myid_fqdn_key_warning = TRUE;
                }

                next_step = fos_myid_hostname_key;
                ugh = NULL;     /* failure can be recovered from */
            }
            else
            {
                /* we can use our IP as OE identity for initiation */
                if (!logged_myid_fqdn_key_warning)
                {
                    loglog(RC_LOG_SERIOUS
                           , "using our hostname (%s:KEY) as identity!"
                           , myid_str[MYID_HOSTNAME]);
                    logged_myid_fqdn_key_warning = TRUE;
                }
                next_step = fos_our_client;
            }
            break;
#endif

        case fos_our_client:    /* TXT for our client */
            {
                /* Our client is not us: we must check the TXT records.
                 * Note: if c is different this time, there is
                 * a chance that we did the wrong query.
                 * If so, treat as a kind of failure.
                 */
                const struct RSA_private_key *our_RSA_pri = get_RSA_private_key(c);

                next_step = fos_his_client;     /* normal situation */

                passert(sr != NULL);

                if (our_RSA_pri == NULL)
                {
                    ugh = "we don't know our own RSA key";
                }
                else if (sameaddr(&sr->this.host_addr, &b->our_client))
                {
                    /* this wasn't true when we started -- bail */
                    ugh = "our IP address changed underfoot";
                }
                else if (!same_id(&ac->sgw_id, &sr->this.id))
                {
                    /* this wasn't true when we started -- bail */
                    ugh = "our ID changed underfoot";
                }
                else
                {
                    /* Similar to code in quick_inI1_outR1_tail
                     * for checking the other side.
                     */
                    struct gw_info *gwp;

                    ugh = "no TXT RR for our client delegates us";
                    for (gwp = ac->gateways_from_dns; gwp != NULL; gwp = gwp->next)
                    {
                        passert(same_id(&gwp->gw_id, &sr->this.id));

                        ugh = "TXT RR for our client has wrong key";
                        /* If there is a key from the TXT record,
                         * we count it as a win if we match the key.
                         * If there was no key, we have a tentative win:
                         * we need to check our KEY record to be sure.
                         */
                        if (!gwp->gw_key_present)
                        {
                            /* Success, but the TXT had no key
                             * so we must check our our own KEY records.
                             */
                            next_step = fos_our_txt;
                            ugh = NULL; /* good! */
                            break;
                        }
                        if (same_RSA_public_key(&our_RSA_pri->pub, &gwp->key->u.rsa))
                        {
                            ugh = NULL; /* good! */
                            break;
                        }
                    }
                }
            }
            break;

        case fos_our_txt:       /* TXT for us */
            {
                /* Check if TXT lookup yielded good results.
                 * Looking up based on our ID.  Used if
                 * client is ourself, or if TXT had no public key.
                 * Note: if c is different this time, there is
                 * a chance that we did the wrong query.
                 * If so, treat as a kind of failure.
                 */
                const struct RSA_private_key *our_RSA_pri = get_RSA_private_key(c);

                next_step = fos_his_client;     /* unless we decide to look for KEY RR */

                if (our_RSA_pri == NULL)
                {
                    ugh = "we don't know our own RSA key";
                }
                else if (!same_id(&ac->id, &c->spd.this.id))
                {
                    ugh = "our ID changed underfoot";
                }
                else
                {
                    /* Similar to code in RSA_check_signature
                     * for checking the other side.
                     */
                    struct gw_info *gwp;

                    ugh = "no TXT RR for us";
                    for (gwp = ac->gateways_from_dns; gwp != NULL; gwp = gwp->next)
                    {
                        passert(same_id(&gwp->gw_id, &sr->this.id));

                        ugh = "TXT RR for us has wrong key";
                        if (gwp->gw_key_present
                        && same_RSA_public_key(&our_RSA_pri->pub, &gwp->key->u.rsa))
                        {
                            DBG(DBG_CONTROL,
                                DBG_log("initiate on demand found TXT with right public key at: %s"
                                        , mycredentialstr));
                            ugh = NULL;
                            break;
                        }
                    }
#ifdef USE_KEYRR
                    if (ugh != NULL)
                    {
                        /* if no TXT with right key, try KEY */
                        DBG(DBG_CONTROL,
                            DBG_log("will try for KEY RR since initiate on demand found %s: %s"
                                    , ugh, mycredentialstr));
                        next_step = fos_our_key;
                        ugh = NULL;
                    }
#endif
                }
            }
            break;

#ifdef USE_KEYRR
        case fos_our_key:       /* KEY for us */
            {
                /* Check if KEY lookup yielded good results.
                 * Looking up based on our ID.  Used if
                 * client is ourself, or if TXT had no public key.
                 * Note: if c is different this time, there is
                 * a chance that we did the wrong query.
                 * If so, treat as a kind of failure.
                 */
                const struct RSA_private_key *our_RSA_pri = get_RSA_private_key(c);

                next_step = fos_his_client;     /* always */

                if (our_RSA_pri == NULL)
                {
                    ugh = "we don't know our own RSA key";
                }
                else if (!same_id(&ac->id, &c->spd.this.id))
                {
                    ugh = "our ID changed underfoot";
                }
                else
                {
                    /* Similar to code in RSA_check_signature
                     * for checking the other side.
                     */
                    pubkey_list_t *kr;

                    ugh = "no KEY RR found for us (and no good TXT RR)";
                    for (kr = ac->keys_from_dns; kr != NULL; kr = kr->next)
                    {
                        ugh = "all our KEY RRs have the wrong public key (and no good TXT RR)";
                        if (kr->key->alg == PUBKEY_ALG_RSA
                        && same_RSA_public_key(&our_RSA_pri->pub, &kr->key->u.rsa))
                        {
                            /* do this only once a day */
                            if (!logged_txt_warning)
                            {
                                loglog(RC_LOG_SERIOUS
                                       , "found KEY RR but not TXT RR for %s. See http://www.freeswan.org/err/txt-change.html."
                                       , mycredentialstr);
                                logged_txt_warning = TRUE;
                            }
                            ugh = NULL; /* good! */
                            break;
                        }
                    }
                }
            }
            break;
#endif /* USE_KEYRR */

        case fos_his_client:    /* TXT for his client */
            {
                /* We've finished last DNS queries: TXT for his client.
                 * Using the information, try to instantiate a connection
                 * and start negotiating.
                 * We now know the peer.  The chosing of "c" ignored this,
                 * so we will disregard its current value.
                 * !!! We need to randomize the entry in gw that we choose.
                 */
                next_step = fos_done;   /* no more queries */

                c = build_outgoing_opportunistic_connection(ac->gateways_from_dns
                                                            , &b->our_client
                                                            , &b->peer_client);

                if (c == NULL)
                {
                    /* We cannot seem to instantiate a suitable connection:
                     * complain clearly.
                     */
                    char ocb[ADDRTOT_BUF]
                        , pcb[ADDRTOT_BUF]
                        , pb[ADDRTOT_BUF];

                    addrtot(&b->our_client, 0, ocb, sizeof(ocb));
                    addrtot(&b->peer_client, 0, pcb, sizeof(pcb));
                    passert(id_is_ipaddr(&ac->gateways_from_dns->gw_id));
                    addrtot(&ac->gateways_from_dns->gw_id.ip_addr, 0, pb, sizeof(pb));
                    loglog(RC_OPPOFAILURE
                        , "no suitable connection for opportunism"
                          " between %s and %s with %s as peer"
                        , ocb, pcb, pb);

#ifdef KLIPS
                    if (b->held)
                    {
                        /* Replace HOLD with PASS.
                         * The type of replacement *ought* to be
                         * specified by policy.
                         */
                        (void) replace_bare_shunt(&b->our_client, &b->peer_client
                            , BOTTOM_PRIO
                            , SPI_PASS  /* fail into PASS */
                            , TRUE, b->transport_proto
                            , "no suitable connection");
                    }
#endif
                }
                else
                {
                    /* If we are to proceed asynchronously, b->whackfd will be NULL_FD. */
                    passert(c->kind == CK_INSTANCE);
                    passert(c->gw_info != NULL);
                    passert(HAS_IPSEC_POLICY(c->policy));
                    passert(LHAS(LELEM(RT_UNROUTED) | LELEM(RT_ROUTED_PROSPECTIVE), c->spd.routing));
#ifdef KLIPS
                    if (b->held)
                    {
                        /* what should we do on failure? */
                        (void) assign_hold(c, &c->spd
                                           , b->transport_proto
                                           , &b->our_client, &b->peer_client);
                    }
#endif
                    c->gw_info->key->last_tried_time = now();
                    ipsecdoi_initiate(b->whackfd, c, c->policy, 1, SOS_NOBODY);
                    b->whackfd = NULL_FD;       /* protect from close */
                }
            }
            break;

        default:
            bad_case(b->step);
        }

        /* the second chunk: initiate the next DNS query (if any) */
        DBG(DBG_CONTROL,
        {
            char ours[ADDRTOT_BUF];
            char his[ADDRTOT_BUF];

            addrtot(&b->our_client, 0, ours, sizeof(ours));
            addrtot(&b->peer_client, 0, his, sizeof(his));
            DBG_log("initiate on demand from %s to %s new state: %s with ugh: %s"
                    , ours, his, oppo_step_name[b->step], ugh ? ugh : "ok");
        });

        if (ugh != NULL)
        {
            b->policy_prio = c->prio;
            b->failure_shunt = shunt_policy_spi(c, FALSE);
            cannot_oppo(c, b, ugh);
        }
        else if (next_step == fos_done)
        {
            /* nothing to do */
        }
        else
        {
            /* set up the next query */
            struct find_oppo_continuation *cr = alloc_thing(struct find_oppo_continuation
                , "opportunistic continuation");
            struct id id;

            b->policy_prio = c->prio;
            b->failure_shunt = shunt_policy_spi(c, FALSE);
            cr->b = *b; /* copy; start hand off of whackfd */
            cr->b.failure_ok = FALSE;
            cr->b.step = next_step;

            for (sr = &c->spd
            ; sr!=NULL && !sameaddr(&sr->this.host_addr, &b->our_client)
            ; sr = sr->next)
                ;

            if (sr == NULL)
                sr = &c->spd;

            /* If a %hold shunt has replaced the eroute for this template,
             * record this fact.
             */
            if (b->held
            && sr->routing == RT_ROUTED_PROSPECTIVE && eclipsable(sr))
            {
                sr->routing = RT_ROUTED_ECLIPSED;
                eclipse_count++;
            }

            /* Switch to issue next query.
             * A case may turn out to be unnecessary.  If so, it falls
             * through to the next case.
             * Figuring out what %myid can stand for must be done before
             * our client credentials are looked up: we must know what
             * the client credentials may use to identify us.
             * On the other hand, our own credentials should be looked
             * up after our clients in case our credentials are not
             * needed at all.
             * XXX this is a wasted effort if we don't have credentials
             * BUT they are not needed.
             */
            switch (next_step)
            {
            case fos_myid_ip_txt:
                if (c->spd.this.id.kind == ID_MYID
                && myid_state != MYID_SPECIFIED)
                {
                    cr->b.failure_ok = TRUE;
                    cr->b.want = b->want = "TXT record for IP address as %myid";
                    ugh = start_adns_query(&myids[MYID_IP]
                        , &myids[MYID_IP]
                        , T_TXT
                        , continue_oppo
                        , &cr->ac);
                    break;
                }
                cr->b.step = fos_myid_hostname_txt;
                /* fall through */

            case fos_myid_hostname_txt:
                if (c->spd.this.id.kind == ID_MYID
                && myid_state != MYID_SPECIFIED)
                {
#ifdef USE_KEYRR
                    cr->b.failure_ok = TRUE;
#else
                    cr->b.failure_ok = FALSE;
#endif
                    cr->b.want = b->want = "TXT record for hostname as %myid";
                    ugh = start_adns_query(&myids[MYID_HOSTNAME]
                        , &myids[MYID_HOSTNAME]
                        , T_TXT
                        , continue_oppo
                        , &cr->ac);
                    break;
                }

#ifdef USE_KEYRR
                cr->b.step = fos_myid_ip_key;
                /* fall through */

            case fos_myid_ip_key:
                if (c->spd.this.id.kind == ID_MYID
                && myid_state != MYID_SPECIFIED)
                {
                    cr->b.failure_ok = TRUE;
                    cr->b.want = b->want = "KEY record for IP address as %myid (no good TXT)";
                    ugh = start_adns_query(&myids[MYID_IP]
                        , (const struct id *) NULL      /* security gateway meaningless */
                        , T_KEY
                        , continue_oppo
                        , &cr->ac);
                    break;
                }
                cr->b.step = fos_myid_hostname_key;
                /* fall through */

            case fos_myid_hostname_key:
                if (c->spd.this.id.kind == ID_MYID
                && myid_state != MYID_SPECIFIED)
                {
                    cr->b.failure_ok = FALSE;           /* last attempt! */
                    cr->b.want = b->want = "KEY record for hostname as %myid (no good TXT)";
                    ugh = start_adns_query(&myids[MYID_HOSTNAME]
                        , (const struct id *) NULL      /* security gateway meaningless */
                        , T_KEY
                        , continue_oppo
                        , &cr->ac);
                    break;
                }
#endif
                cr->b.step = fos_our_client;
                /* fall through */

            case fos_our_client:        /* TXT for our client */
                if (!sameaddr(&c->spd.this.host_addr, &b->our_client))
                {
                    /* Check that at least one TXT(reverse(b->our_client)) is workable.
                     * Note: {unshare|free}_id_content not needed for id: ephemeral.
                     */
                    cr->b.want = b->want = "our client's TXT record";
                    iptoid(&b->our_client, &id);
                    ugh = start_adns_query(&id
                        , &c->spd.this.id       /* we are the security gateway */
                        , T_TXT
                        , continue_oppo
                        , &cr->ac);
                    break;
                }
                cr->b.step = fos_our_txt;
                /* fall through */

            case fos_our_txt:   /* TXT for us */
                cr->b.failure_ok = b->failure_ok = TRUE;
                cr->b.want = b->want = "our TXT record";
                ugh = start_adns_query(&sr->this.id
                    , &sr->this.id             /* we are the security gateway XXX - maybe ignore? mcr */
                    , T_TXT
                    , continue_oppo
                    , &cr->ac);
                break;

#ifdef USE_KEYRR
            case fos_our_key:   /* KEY for us */
                cr->b.want = b->want = "our KEY record";
                cr->b.failure_ok = b->failure_ok = FALSE;
                ugh = start_adns_query(&sr->this.id
                    , (const struct id *) NULL  /* security gateway meaningless */
                    , T_KEY
                    , continue_oppo
                    , &cr->ac);
                break;
#endif /* USE_KEYRR */

            case fos_his_client:        /* TXT for his client */
                /* note: {unshare|free}_id_content not needed for id: ephemeral */
                cr->b.want = b->want = "target's TXT record";
                cr->b.failure_ok = b->failure_ok = FALSE;
                iptoid(&b->peer_client, &id);
                ugh = start_adns_query(&id
                    , (const struct id *) NULL  /* security gateway unconstrained */
                    , T_TXT
                    , continue_oppo
                    , &cr->ac);
                break;

            default:
                bad_case(next_step);
            }

            if (ugh == NULL)
                b->whackfd = NULL_FD;   /* complete hand-off */
            else
                cannot_oppo(c, b, ugh);
        }
    }
    close_any(b->whackfd);
}

void
terminate_connection(const char *nm)
{
    /* Loop because more than one may match (master and instances)
     * But at least one is required (enforced by con_by_name).
     */
    struct connection *c = con_by_name(nm, TRUE);

    if (c == NULL || !c->ikev1)
        return;

    do
    {
        struct connection *n = c->ac_next;  /* grab this before c might disappear */

        if (streq(c->name, nm)
        && c->kind >= CK_PERMANENT
        && !NEVER_NEGOTIATE(c->policy))
        {
            set_cur_connection(c);
            plog("terminating SAs using this connection");
            c->policy &= ~POLICY_UP;
            flush_pending_by_connection(c);
            delete_states_by_connection(c, FALSE);
            reset_cur_connection();
        }
        c = n;
    } while (c != NULL);
}

/* an ISAKMP SA has been established.
 * Note the serial number, and release any connections with
 * the same peer ID but different peer IP address.
 */
bool uniqueIDs = FALSE; /* --uniqueids? */

void
ISAKMP_SA_established(struct connection *c, so_serial_t serial)
{
    c->newest_isakmp_sa = serial;

    /* the connection is now oriented so that we are able to determine
     * whether we are a mode config server with a virtual IP to send.
     */
    if (!isanyaddr(&c->spd.that.host_srcip) && !c->spd.that.has_natip)
        c->spd.that.modecfg = TRUE;
        
    if (uniqueIDs)
    {
        /* for all connections: if the same Phase 1 IDs are used
         * for a different IP address, unorient that connection.
         */
        struct connection *d;

        for (d = connections; d != NULL; )
        {
            struct connection *next = d->ac_next;       /* might move underneath us */

            if (d->kind >= CK_PERMANENT
            && same_id(&c->spd.this.id, &d->spd.this.id)
            && same_id(&c->spd.that.id, &d->spd.that.id)
            && !sameaddr(&c->spd.that.host_addr, &d->spd.that.host_addr))
            {
                release_connection(d, FALSE);
            }
            d = next;
        }
    }
}

/* Find the connection to connection c's peer's client with the
 * largest value of .routing.  All other things being equal,
 * preference is given to c.  If none is routed, return NULL.
 *
 * If erop is non-null, set *erop to a connection sharing both
 * our client subnet and peer's client subnet with the largest value
 * of .routing.  If none is erouted, set *erop to NULL.
 *
 * The return value is used to find other connections sharing a route.
 * *erop is used to find other connections sharing an eroute.
 */
struct connection *
route_owner(struct connection *c
            , struct spd_route **srp
            , struct connection **erop
            , struct spd_route **esrp)
{
    struct connection *d
        , *best_ro = c
        , *best_ero = c;
    struct spd_route *srd, *src;
    struct spd_route *best_sr, *best_esr;
    enum routing_t best_routing, best_erouting;

    passert(oriented(*c));
    best_sr  = NULL;
    best_esr = NULL;
    best_routing = c->spd.routing;
    best_erouting = best_routing;

    for (d = connections; d != NULL; d = d->ac_next)
    {
        for (srd = &d->spd; srd; srd = srd->next)
        {
            if (srd->routing == RT_UNROUTED)
                continue;

            for (src = &c->spd; src; src=src->next)
            {
                if (!samesubnet(&src->that.client, &srd->that.client))
                    continue;
                if (src->that.protocol != srd->that.protocol)
                    continue;
                if (src->that.port != srd->that.port)
                    continue;
                passert(oriented(*d));
                if (srd->routing > best_routing)
                {
                    best_ro = d;
                    best_sr = srd;
                    best_routing = srd->routing;
                }

                if (!samesubnet(&src->this.client, &srd->this.client))
                    continue;
                if (src->this.protocol != srd->this.protocol)
                    continue;
                if (src->this.port != srd->this.port)
                    continue;
                if (srd->routing > best_erouting)
                {
                    best_ero = d;
                    best_esr = srd;
                    best_erouting = srd->routing;
                }
            }
        }
    }

    DBG(DBG_CONTROL,
        {
            char cib[CONN_INST_BUF];
            err_t m = builddiag("route owner of \"%s\"%s %s:"
                , c->name
                , (fmt_conn_instance(c, cib), cib)
                , enum_name(&routing_story, c->spd.routing));

            if (!routed(best_ro->spd.routing))
                m = builddiag("%s NULL", m);
            else if (best_ro == c)
                m = builddiag("%s self", m);
            else
                m = builddiag("%s \"%s\"%s %s", m
                    , best_ro->name
                    , (fmt_conn_instance(best_ro, cib), cib)
                    , enum_name(&routing_story, best_ro->spd.routing));

            if (erop != NULL)
            {
                m = builddiag("%s; eroute owner:", m);
                if (!erouted(best_ero->spd.routing))
                    m = builddiag("%s NULL", m);
                else if (best_ero == c)
                    m = builddiag("%s self", m);
                else
                    m = builddiag("%s \"%s\"%s %s", m
                        , best_ero->name
                        , (fmt_conn_instance(best_ero, cib), cib)
                        , enum_name(&routing_story, best_ero->spd.routing));
            }

            DBG_log("%s", m);
        });

    if (erop != NULL)
        *erop = erouted(best_erouting)? best_ero : NULL;

    if (srp != NULL )
    {
        *srp = best_sr;
        if (esrp != NULL )
            *esrp = best_esr;
    }

    return routed(best_routing)? best_ro : NULL;
}

/* Find a connection that owns the shunt eroute between subnets.
 * There ought to be only one.
 * This might get to be a bottleneck -- try hashing if it does.
 */
struct connection *
shunt_owner(const ip_subnet *ours, const ip_subnet *his)
{
    struct connection *c;
    struct spd_route *sr;

    for (c = connections; c != NULL; c = c->ac_next)
    {
        for (sr = &c->spd; sr; sr = sr->next)
        {
            if (shunt_erouted(sr->routing)
            && samesubnet(ours, &sr->this.client)
            && samesubnet(his, &sr->that.client))
                return c;
        }
    }
    return NULL;
}

/* Find some connection with this pair of hosts.
 * We don't know enough to chose amongst those available.
 * ??? no longer usefully different from find_host_pair_connections
 */
struct connection *
find_host_connection(const ip_address *me, u_int16_t my_port
, const ip_address *him, u_int16_t his_port, lset_t policy)
{
    struct connection *c = find_host_pair_connections(me, my_port, him, his_port);

    if (policy != LEMPTY)
    {
        lset_t auth_requested  = policy & POLICY_ID_AUTH_MASK;

        /* if we have requirements for the policy,
         * choose the first matching connection.
         */
        while (c != NULL)
        {
            if (c->policy & auth_requested)
            {
                break;
            }
            c = c->hp_next;
        }
    }
    return c;
}

/* given an up-until-now satisfactory connection, find the best connection
 * now that we just got the Phase 1 Id Payload from the peer.
 *
 * Comments in the code describe the (tricky!) matching criteria.
 * Although this routine could handle the initiator case,
 * it isn't currently called in this case.
 * If it were, it could "upgrade" an Opportunistic Connection
 * to a Road Warrior Connection if a suitable Peer ID were found.
 *
 * In RFC 2409 "The Internet Key Exchange (IKE)",
 * in 5.1 "IKE Phase 1 Authenticated With Signatures", describing Main
 * Mode:
 *
 *         Initiator                          Responder
 *        -----------                        -----------
 *         HDR, SA                     -->
 *                                     <--    HDR, SA
 *         HDR, KE, Ni                 -->
 *                                     <--    HDR, KE, Nr
 *         HDR*, IDii, [ CERT, ] SIG_I -->
 *                                     <--    HDR*, IDir, [ CERT, ] SIG_R
 *
 * In 5.4 "Phase 1 Authenticated With a Pre-Shared Key":
 *
 *               HDR, SA             -->
 *                                   <--    HDR, SA
 *               HDR, KE, Ni         -->
 *                                   <--    HDR, KE, Nr
 *               HDR*, IDii, HASH_I  -->
 *                                   <--    HDR*, IDir, HASH_R
 *
 * refine_host_connection could be called in two case:
 *
 * - the Responder receives the IDii payload:
 *   + [PSK] after using PSK to decode this message
 *   + before sending its IDir payload
 *   + before using its ID in HASH_R computation
 *   + [DSig] before using its private key to sign SIG_R
 *   + before using the Initiator's ID in HASH_I calculation
 *   + [DSig] before using the Initiator's public key to check SIG_I
 *
 * - the Initiator receives the IDir payload:
 *   + [PSK] after using PSK to encode previous message and decode this message
 *   + after sending its IDii payload
 *   + after using its ID in HASH_I computation
 *   + [DSig] after using its private key to sign SIG_I
 *   + before using the Responder's ID to compute HASH_R
 *   + [DSig] before using Responder's public key to check SIG_R
 *
 * refine_host_connection can choose a different connection, as long as
 * nothing already used is changed.
 *
 * In the Initiator case, the particular connection might have been
 * specified by whatever provoked Pluto to initiate.  For example:
 *      whack --initiate connection-name
 * The advantages of switching connections when we're the Initiator seem
 * less important than the disadvantages, so after FreeS/WAN 1.9, we
 * don't do this.
 */
#define PRIO_NO_MATCH_FOUND     2048

struct connection *
refine_host_connection(const struct state *st, const struct id *peer_id
, chunk_t peer_ca)
{
    struct connection *c = st->st_connection;
    struct connection *d;
    struct connection *best_found = NULL;
    u_int16_t auth = st->st_oakley.auth;
    lset_t auth_policy;
    const chunk_t *psk = NULL;
    bool wcpip; /* wildcard Peer IP? */
    int best_prio = PRIO_NO_MATCH_FOUND;
    int wildcards, our_pathlen, peer_pathlen;

    if (same_id(&c->spd.that.id, peer_id)
    && trusted_ca(peer_ca, c->spd.that.ca, &peer_pathlen)
    && peer_pathlen == 0
    && match_requested_ca(c->requested_ca, c->spd.this.ca, &our_pathlen)
    && our_pathlen == 0)
    {
        DBG(DBG_CONTROL,
            DBG_log("current connection is a full match"
                    " -- no need to look further");
        )
        return c;
    }

    switch (auth)
    {
    case OAKLEY_PRESHARED_KEY:
        auth_policy = POLICY_PSK;
        psk = get_preshared_secret(c);
        /* It should be virtually impossible to fail to find PSK:
         * we just used it to decode the current message!
         */
        if (psk == NULL)
            return NULL;        /* cannot determine PSK! */
        break;
    case XAUTHInitPreShared:
    case XAUTHRespPreShared:
        auth_policy = POLICY_XAUTH_PSK;
        psk = get_preshared_secret(c);
        if (psk == NULL)
            return NULL;        /* cannot determine PSK! */
        break;
    case OAKLEY_RSA_SIG:
        auth_policy = POLICY_RSASIG;
        break;
    case XAUTHInitRSA:
    case XAUTHRespRSA:
        auth_policy = POLICY_XAUTH_RSASIG;
        break;
    default:
        bad_case(auth);
    }

    /* The current connection won't do: search for one that will.
     * First search for one with the same pair of hosts.
     * If that fails, search for a suitable Road Warrior or Opportunistic
     * connection (i.e. wildcard peer IP).
     * We need to match:
     * - peer_id (slightly complicated by instantiation)
     * - if PSK auth, the key must not change (we used it to decode message)
     * - policy-as-used must be acceptable to new connection
     */
    d = c->host_pair->connections;
    for (wcpip = FALSE; ; wcpip = TRUE)
    {
        for (; d != NULL; d = d->hp_next)
        {
            const char *match_name[] = {"no", "ok"};

            bool matching_id = match_id(peer_id
                                        , &d->spd.that.id, &wildcards);
            bool matching_auth = (d->policy & auth_policy) != LEMPTY;

            bool matching_trust = trusted_ca(peer_ca
                                        , d->spd.that.ca, &peer_pathlen);
            bool matching_request = match_requested_ca(c->requested_ca
                                        , d->spd.this.ca, &our_pathlen);
            bool match = matching_id && matching_auth && matching_trust;

            int prio = (MAX_WILDCARDS + 1) * !matching_request + wildcards;

            prio = (MAX_CA_PATH_LEN + 1) * prio + peer_pathlen;
            prio = (MAX_CA_PATH_LEN + 1) * prio + our_pathlen;

            DBG(DBG_CONTROLMORE,
                DBG_log("%s: %s match (id: %s, auth: %s, trust: %s, request: %s, prio: %4d)"
                    , d->name
                    , match ? "full":" no"
                    , match_name[matching_id]
                    , match_name[matching_auth]
                    , match_name[matching_trust]
                    , match_name[matching_request]
                    , match ? prio:PRIO_NO_MATCH_FOUND)
            )

            /* do we have a match? */
            if (!match)
                continue;

            /* ignore group connections */
            if (d->policy & POLICY_GROUP)
                continue;

            if (c->spd.that.host_port != d->spd.that.host_port
            && d->kind == CK_INSTANCE)
            {
                continue;
            }

            switch (auth)
            {
            case OAKLEY_PRESHARED_KEY:
            case XAUTHInitPreShared:
            case XAUTHRespPreShared:
                /* secret must match the one we already used */
                {
                    const chunk_t *dpsk = get_preshared_secret(d);

                    if (dpsk == NULL)
                        continue;       /* no secret */

                    if (psk != dpsk)
                        if (psk->len != dpsk->len
                        || memcmp(psk->ptr, dpsk->ptr, psk->len) != 0)
                            continue;   /* different secret */
                }
                break;

            case OAKLEY_RSA_SIG:
            case XAUTHInitRSA:
            case XAUTHRespRSA:
                /*
                 * We must at least be able to find our private key
                .*/
                if (d->spd.this.sc == NULL              /* no smartcard */
                && get_RSA_private_key(d) == NULL)      /* no private key */
                    continue;
                break;

            default:
                bad_case(auth);
            }

            /* d has passed all the tests.
             * We'll go with it if the Peer ID was an exact match.
             */
            if (prio == 0)
            {
                return d;
            }

            /* We'll remember it as best_found in case an exact
             * match doesn't come along.
             */
            if (prio < best_prio)
            {
                best_found = d;
                best_prio = prio;
            }
        }
        if (wcpip)
            return best_found;  /* been around twice already */

        /* Starting second time around.
         * We're willing to settle for a connection that needs Peer IP
         * instantiated: Road Warrior or Opportunistic.
         * Look on list of connections for host pair with wildcard Peer IP
         */
        d = find_host_pair_connections(&c->spd.this.host_addr, c->spd.this.host_port
            , (ip_address *)NULL, c->spd.that.host_port);
    }
}

/**
 * With virtual addressing, we must not allow someone to use an already
 * used (by another id) addr/net.
 */
static bool
is_virtual_net_used(const ip_subnet *peer_net, const struct id *peer_id)
{
    struct connection *d;

    for (d = connections; d != NULL; d = d->ac_next)
    {
        switch (d->kind)
        {
        case CK_PERMANENT:
        case CK_INSTANCE:
            if ((subnetinsubnet(peer_net,&d->spd.that.client) ||
                 subnetinsubnet(&d->spd.that.client,peer_net))
            && !same_id(&d->spd.that.id, peer_id))
            {
                char buf[BUF_LEN];
                char client[SUBNETTOT_BUF];

                subnettot(peer_net, 0, client, sizeof(client));
                idtoa(&d->spd.that.id, buf, sizeof(buf));
                plog("Virtual IP %s is already used by '%s'", client, buf);
                idtoa(peer_id, buf, sizeof(buf));
                plog("Your ID is '%s'", buf);
                return TRUE; /* already used by another one */
            }
            break;
        case CK_GOING_AWAY:
        default:
        break;
        }
    }
    return FALSE; /* you can safely use it */
}

/* find_client_connection: given a connection suitable for ISAKMP
 * (i.e. the hosts match), find a one suitable for IPSEC
 * (i.e. with matching clients).
 *
 * If we don't find an exact match (not even our current connection),
 * we try for one that still needs instantiation.  Try Road Warrior
 * abstract connections and the Opportunistic abstract connections.
 * This requires inverse instantiation: abstraction.
 *
 * After failing to find an exact match, we abstract the peer
 * to be NO_IP (the wildcard value).  This enables matches with
 * Road Warrior and Opportunistic abstract connections.
 *
 * After failing that search, we also abstract the Phase 1 peer ID
 * if possible.  If the peer's ID was the peer's IP address, we make
 * it NO_ID; instantiation will make it the peer's IP address again.
 *
 * If searching for a Road Warrior abstract connection fails,
 * and conditions are suitable, we search for the best Opportunistic
 * abstract connection.
 *
 * Note: in the end, both Phase 1 IDs must be preserved, after any
 * instantiation.  They are the IDs that have been authenticated.
 */

#define PATH_WEIGHT     1
#define WILD_WEIGHT     (MAX_CA_PATH_LEN+1)
#define PRIO_WEIGHT     (MAX_WILDCARDS+1)*WILD_WEIGHT

/* fc_try: a helper function for find_client_connection */
static struct connection *
fc_try(const struct connection *c
, struct host_pair *hp
, const struct id *peer_id
, const ip_subnet *our_net
, const ip_subnet *peer_net
, const u_int8_t our_protocol
, const u_int16_t our_port
, const u_int8_t peer_protocol
, const u_int16_t peer_port
, chunk_t peer_ca
, const ietfAttrList_t *peer_list)
{
    struct connection *d;
    struct connection *best = NULL;
    policy_prio_t best_prio = BOTTOM_PRIO;
    int wildcards, pathlen;

    const bool peer_net_is_host = subnetisaddr(peer_net, &c->spd.that.host_addr);

    for (d = hp->connections; d != NULL; d = d->hp_next)
    {
        struct spd_route *sr;

        if (d->policy & POLICY_GROUP)
            continue;

        if (!(same_id(&c->spd.this.id, &d->spd.this.id)
        && match_id(&c->spd.that.id, &d->spd.that.id, &wildcards)
        && trusted_ca(peer_ca, d->spd.that.ca, &pathlen)
        && group_membership(peer_list, d->name, d->spd.that.groups)))
            continue;

        /* compare protocol and ports */
        if (d->spd.this.protocol != our_protocol
        ||  d->spd.this.port != our_port
        ||  d->spd.that.protocol != peer_protocol
        || (d->spd.that.port != peer_port && !d->spd.that.has_port_wildcard))
            continue;

        /* non-Opportunistic case:
         * our_client must match.
         *
         * So must peer_client, but the testing is complicated
         * by the fact that the peer might be a wildcard
         * and if so, the default value of that.client
         * won't match the default peer_net.  The appropriate test:
         *
         * If d has a peer client, it must match peer_net.
         * If d has no peer client, peer_net must just have peer itself.
         */

        for (sr = &d->spd; best != d && sr != NULL; sr = sr->next)
        {
            policy_prio_t prio;
#ifdef DEBUG
            if (DBGP(DBG_CONTROLMORE))
            {
                char s1[SUBNETTOT_BUF],d1[SUBNETTOT_BUF];
                char s3[SUBNETTOT_BUF],d3[SUBNETTOT_BUF];

                subnettot(our_net,  0, s1, sizeof(s1));
                subnettot(peer_net, 0, d1, sizeof(d1));
                subnettot(&sr->this.client,  0, s3, sizeof(s3));
                subnettot(&sr->that.client,  0, d3, sizeof(d3));
                DBG_log("  fc_try trying "
                        "%s:%s:%d/%d -> %s:%d/%d vs %s:%s:%d/%d -> %s:%d/%d"
                        , c->name, s1, c->spd.this.protocol, c->spd.this.port
                                 , d1, c->spd.that.protocol, c->spd.that.port
                        , d->name, s3, sr->this.protocol, sr->this.port
                                 , d3, sr->that.protocol, sr->that.port);
            }
#endif /* DEBUG */

            if (!samesubnet(&sr->this.client, our_net))
                continue;

            if (sr->that.has_client)
            {
                if (sr->that.has_client_wildcard)
                {
                    if (!subnetinsubnet(peer_net, &sr->that.client))
                        continue;
                }
                else
                {
                    if (!samesubnet(&sr->that.client, peer_net) && !is_virtual_connection(d))
                        continue;
                    if (is_virtual_connection(d)
                    && (!is_virtual_net_allowed(d, peer_net, &c->spd.that.host_addr)
                        || is_virtual_net_used(peer_net, peer_id?peer_id:&c->spd.that.id)))
                            continue;
                }
            }
            else
            {
                if (!peer_net_is_host)
                    continue;
            }

            /* We've run the gauntlet -- success:
             * We've got an exact match of subnets.
             * The connection is feasible, but we continue looking for the best.
             * The highest priority wins, implementing eroute-like rule.
             * - a routed connection is preferrred
             * - given that, the smallest number of ID wildcards are preferred
             * - given that, the shortest CA pathlength is preferred
             */
            prio = PRIO_WEIGHT * routed(sr->routing)
                 + WILD_WEIGHT * (MAX_WILDCARDS - wildcards)
                 + PATH_WEIGHT * (MAX_CA_PATH_LEN - pathlen)
                 + 1;
            if (prio > best_prio)
            {
                best = d;
                best_prio = prio;
            }
        }
    }

    if (best != NULL && NEVER_NEGOTIATE(best->policy))
        best = NULL;

    DBG(DBG_CONTROLMORE,
        DBG_log("  fc_try concluding with %s [%ld]"
                , (best ? best->name : "none"), best_prio)
    )
    return best;
}

static struct connection *
fc_try_oppo(const struct connection *c
, struct host_pair *hp
, const ip_subnet *our_net
, const ip_subnet *peer_net
, const u_int8_t our_protocol
, const u_int16_t our_port
, const u_int8_t peer_protocol
, const u_int16_t peer_port
, chunk_t peer_ca
, const ietfAttrList_t *peer_list)
{
    struct connection *d;
    struct connection *best = NULL;
    policy_prio_t best_prio = BOTTOM_PRIO;
    int wildcards, pathlen;

    for (d = hp->connections; d != NULL; d = d->hp_next)
    {
        struct spd_route *sr;
        policy_prio_t prio;

        if (d->policy & POLICY_GROUP)
            continue;

        if (!(same_id(&c->spd.this.id, &d->spd.this.id)
        && match_id(&c->spd.that.id, &d->spd.that.id, &wildcards)
        && trusted_ca(peer_ca, d->spd.that.ca, &pathlen)
        && group_membership(peer_list, d->name, d->spd.that.groups)))
            continue;

        /* compare protocol and ports */
        if (d->spd.this.protocol != our_protocol
        ||  d->spd.this.port != our_port
        ||  d->spd.that.protocol != peer_protocol
        || (d->spd.that.port != peer_port && !d->spd.that.has_port_wildcard))
            continue;

        /* Opportunistic case:
         * our_net must be inside d->spd.this.client
         * and peer_net must be inside d->spd.that.client
         * Note: this host_pair chain also has shunt
         * eroute conns (clear, drop), but they won't
         * be marked as opportunistic.
         */
        for (sr = &d->spd; sr != NULL; sr = sr->next)
        {
#ifdef DEBUG
            if (DBGP(DBG_CONTROLMORE))
            {
                char s1[SUBNETTOT_BUF],d1[SUBNETTOT_BUF];
                char s3[SUBNETTOT_BUF],d3[SUBNETTOT_BUF];

                subnettot(our_net,  0, s1, sizeof(s1));
                subnettot(peer_net, 0, d1, sizeof(d1));
                subnettot(&sr->this.client,  0, s3, sizeof(s3));
                subnettot(&sr->that.client,  0, d3, sizeof(d3));
                DBG_log("  fc_try_oppo trying %s:%s -> %s vs %s:%s -> %s"
                        , c->name, s1, d1, d->name, s3, d3);
            }
#endif /* DEBUG */