implemented support of resolve plugin

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

/* information about connections between hosts and clients
 * Copyright (C) 1998-2002  D. Hugh Redelmeier.
 * Copyright (C) 2009 Andreas Steffen - Hochschule fuer Technik Rapperswil
 *
 * 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.
 */

#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 "kameipsec.h"

#include <hydra.h>
#include <credentials/certificates/ac.h>
#include <credentials/keys/private_key.h>

#include "constants.h"
#include "defs.h"
#include "myid.h"
#include "x509.h"
#include "ca.h"
#include "crl.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"
#include "whack_attribute.h"
#include "modecfg.h"

static void flush_pending_by_connection(connection_t *c);  /* forward */

static connection_t *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;
        connection_t *connections;     /* connections with this pair */
        struct pending *pending;    /* awaiting Keying Channel */
        struct host_pair *next;
};

static struct host_pair *host_pairs = NULL;

static connection_t *unoriented_connections = NULL;

/**
 * Check if an id was instantiated by assigning to it the current IP address
 */
bool his_id_was_instantiated(const connection_t *c)
{
        if (c->kind != CK_INSTANCE)
        {
                return FALSE;
        }
        if (id_is_ipaddr(c->spd.that.id))
        {
                identification_t *host;
                bool equal;

                host = identification_create_from_sockaddr((sockaddr_t*)&c->spd.that.host_addr);
                equal = host->equals(host, c->spd.that.id);
                host->destroy(host);
                return equal;
        }
        else
        {
                return TRUE;
        }
}

/**
 * Check to see that IDs of peers match
 */
bool same_peer_ids(const connection_t *c, const connection_t *d,
                                   identification_t *his_id)
{
        return d->spd.this.id->equals(d->spd.this.id, c->spd.this.id) &&
                   d->spd.that.id->equals(d->spd.that.id,
                                                                  his_id ? his_id : c->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)
                        {
                                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 connection_t *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)
        {
                connection_t *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(connection_t *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 = malloc_thing(struct 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.
 */
connection_t *con_by_name(const char *nm, bool strict)
{
        connection_t *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)
                        {
                                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(connection_t *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(connection_t *c, bool relations)
{
        modecfg_attribute_t *ca;
        connection_t *old_cur_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(connection_t, 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(connection_t, hp_next, c, unoriented_connections);
                }
        }
        else
        {
                struct host_pair *hp = c->host_pair;

                list_rm(connection_t, 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);
                        free(hp);
                }
        }
        if (c->kind != CK_GOING_AWAY)
        {
                free(c->spd.that.virt);
        }

        /* release virtual IP address lease if any */
        if (c->spd.that.modecfg && c->spd.that.pool &&
                !isanyaddr(&c->spd.that.host_srcip))
        {
                host_t *vip;

                vip = host_create_from_sockaddr((sockaddr_t*)&c->spd.that.host_srcip);
                hydra->attributes->release_address(hydra->attributes, c->spd.that.pool,
                                                                                   vip, c->spd.that.id);
                vip->destroy(vip);
        }

        /* release requested attributes if any */
        if (c->requested)
        {
                c->requested->destroy_function(c->requested,
                                                                          (void*)modecfg_attribute_destroy);
        }

        /* release other attributes if any */
        if (c->attributes)
        {
                while (c->attributes->remove_last(c->attributes, (void **)&ca) == SUCCESS)
                {
                        hydra->attributes->release(hydra->attributes, ca->handler,
                                                                           c->spd.that.id, ca->type, ca->value);
                        modecfg_attribute_destroy(ca);
                }
                c->attributes->destroy(c->attributes);
        }

        if (c->kind != CK_GOING_AWAY)
        {
                whack_attr->del_pool(whack_attr, c->name);
        }

        /* free internal data */
#ifdef DEBUG
        cur_debugging = old_cur_debugging;
#endif
        free(c->name);
        DESTROY_IF(c->spd.this.id);
        DESTROY_IF(c->spd.this.ca);
        DESTROY_IF(c->spd.this.groups);
        free(c->spd.this.updown);
        free(c->spd.this.pool);
        DESTROY_IF(c->spd.that.id);
        DESTROY_IF(c->spd.that.ca);
        DESTROY_IF(c->spd.that.groups);
        free(c->spd.that.updown);
        free(c->spd.that.pool);
        if (c->requested_ca)
        {
                c->requested_ca->destroy_offset(c->requested_ca,
                                                                                offsetof(identification_t, destroy));
        }
        gw_delref(&c->gw_info);

        lock_certs_and_keys("delete_connection");
        cert_release(c->spd.this.cert);
        scx_release(c->spd.this.sc);
        cert_release(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);

        free(c);
}

/* Delete connections with the specified name */
void delete_connections_by_name(const char *name, bool strict)
{
        connection_t *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)
        {
                delete_connection(connections, TRUE);
        }
}

void release_dead_interfaces(void)
{
        struct host_pair *hp;

        for (hp = host_pairs; hp != NULL; hp = hp->next)
        {
                connection_t **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 */
        {
                connection_t *c = unoriented_connections;

                unoriented_connections = NULL;

                while (c)
                {
                        connection_t *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).
                                                 */
                                                connection_t *c = hp->connections;

                                                hp->connections = NULL;
                                                while (c)
                                                {
                                                        connection_t *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;
        int af = addrtypeof(&e->host_addr);

        if (af != AF_INET && af != AF_INET6)
        {
                return "unknown address family in default_end";
        }

        /* default ID to IP (but only if not NO_IP -- WildCard) */
        if (e->id->get_type(e->id) == ID_ANY && !isanyaddr(&e->host_addr))
        {
                e->id->destroy(e->id);
                e->id = identification_create_from_sockaddr((sockaddr_t*)&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[BUF_LEN];
        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, or a server with a pool */
                client_sep = "===";
                client[0] = '%';
                strcpy(client+1, this->pool ? this->pool : "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 */
        snprintf(host_id, sizeof(host_id), "[%Y]", this->id);

        /* [---hop] */
        hop[0] = '\0';
        hop_sep = "";
        if (that && !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 connection_t *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(connection_t *c)
{
        c->name = clone_str(c->name);
        c->spd.this.id = c->spd.this.id->clone(c->spd.this.id);
        c->spd.this.pool = clone_str(c->spd.this.pool);
        c->spd.this.updown = clone_str(c->spd.this.updown);
        scx_share(c->spd.this.sc);
        cert_share(c->spd.this.cert);
        if (c->spd.this.ca)
        {
                c->spd.this.ca = c->spd.this.ca->clone(c->spd.this.ca);
        }
        if (c->spd.this.groups)
        {
                c->spd.this.groups = c->spd.this.groups->get_ref(c->spd.this.groups);
        }
        c->spd.that.id = c->spd.that.id->clone(c->spd.that.id);
        c->spd.that.pool = clone_str(c->spd.that.pool);
        c->spd.that.updown = clone_str(c->spd.that.updown);
        scx_share(c->spd.that.sc);
        cert_share(c->spd.that.cert);
        if (c->spd.that.ca)
        {
                c->spd.that.ca = c->spd.that.ca->clone(c->spd.that.ca);
        }
        if (c->spd.that.groups)
        {
                c->spd.that.groups = c->spd.that.groups->get_ref(c->spd.that.groups);
        }

        /* 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(char *filename, struct end *dst)
{
        time_t notBefore, notAfter;
        cert_t *cert = NULL;
        certificate_t *certificate;
        bool cached_cert = FALSE;

        /* initialize end certificate */
        dst->cert = NULL;

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

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

        if (cert)
        {
                certificate = cert->cert;

                if (dst->id->get_type(dst->id) == ID_ANY ||
                        !certificate->has_subject(certificate, dst->id))
                {
                        plog( "  id '%Y' not confirmed by certificate, defaulting to '%Y'",
                                 dst->id, certificate->get_subject(certificate));
                        dst->id->destroy(dst->id);
                        dst->id = certificate->get_subject(certificate);
                        dst->id = dst->id->clone(dst->id);
                }

                if (cached_cert)
                {
                        dst->cert = cert;
                }
                else
                {
                        if (!certificate->get_validity(certificate, NULL, &notBefore, &notAfter))
                        {
                                plog("certificate is invalid (valid from %T to %T)",
                                         &notBefore, FALSE, &notAfter, FALSE);
                                cert_free(cert);
                                return;
                        }
                        DBG(DBG_CONTROL,
                                DBG_log("certificate is valid")
                        )
                        add_public_key_from_cert(cert, notAfter, DAL_LOCAL);
                        dst->cert = cert_add(cert);
                }
                certificate = dst->cert->cert;

                /* if no CA is defined, use issuer as default */
                if (dst->ca == NULL && certificate->get_type(certificate) == CERT_X509)
                {
                        identification_t *issuer;

                        issuer = certificate->get_issuer(certificate);
                        dst->ca = issuer->clone(issuer);
                }

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

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

        dst->is_left = is_left;
        dst->id = identification_create_from_string(src->id);
        dst->ca = NULL;

        /* decode CA distinguished name, if any */
        if (src->ca)
        {
                if streq(src->ca, "%same")
                {
                        same_ca = TRUE;
                }
                else if (!streq(src->ca, "%any"))
                {
                        dst->ca = identification_create_from_string(src->ca);
                        if (dst->ca->get_type(dst->ca) != ID_DER_ASN1_DN)
                        {
                                plog("bad CA string '%s', ignored", src->ca);
                                dst->ca->destroy(dst->ca);
                                dst->ca = NULL;
                        }
                }
        }

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

        /* does id has wildcards? */
        dst->has_id_wildcards = dst->id->contains_wildcards(dst->id);

        /* decode group attributes, if any */
        if (src->groups)
        {
                dst->groups = ietf_attributes_create_from_string(src->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 = clone_str(src->updown);
        dst->host_port = src->host_port;

        /* if the sourceip netmask is zero a named pool exists */
        if (src->sourceip_mask == 0)
        {
                dst->pool = clone_str(src->sourceip);
        }

        /* 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)
                {
                        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 */
}

connection_t *find_connection_by_reqid(uint32_t reqid)
{
        connection_t *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;
                connection_t *c = malloc_thing(connection_t);

                zero(c);
                c->name   = clone_str(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)
                {
                         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 : "");

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

                                if (c->alg_info_esp)
                                {
                                        alg_info_snprint(buf, sizeof(buf)
                                                        ,(struct alg_info *)c->alg_info_esp);
                                }
                                DBG_log("esp proposal: %s", buf);
                        )
                        if (c->alg_info_esp)
                        {
                                if (c->alg_info_esp->alg_info_cnt == 0)
                                {
                                         loglog(RC_LOG_SERIOUS, "got 0 esp transforms");
                                }
                        }
                        else
                        {
                                loglog(RC_LOG_SERIOUS, "syntax error in esp string");
                        }
                }

                if (wm->ike)
                {
                        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 : "");

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

                                if (c->alg_info_ike)
                                {
                                        alg_info_snprint(buf, sizeof(buf)
                                                        , (struct alg_info *)c->alg_info_ike);
                                }
                                DBG_log("ike proposal: %s", buf);
                        )
                        if (c->alg_info_ike)
                        {
                                if (c->alg_info_ike->alg_info_cnt == 0)
                                {
                                        loglog(RC_LOG_SERIOUS, "got 0 ike transforms");
                                }
                        }
                        else
                        {
                                loglog(RC_LOG_SERIOUS, "syntax error in ike string");
                        }
                }

                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, wm->name, TRUE);
                same_rightca = extract_end(&c->spd.that, &wm->right, wm->name, FALSE);

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

                (void)orient(c);

                /* if rightsourceip defines a subnet then create an in-memory pool */
                if (whack_attr->add_pool(whack_attr, c->name,
                                                        c->spd.this.is_left ? &wm->right : &wm->left))
                {
                        c->spd.that.pool = clone_str(c->name);
                        c->spd.that.modecfg = TRUE;
                        c->spd.that.has_client = FALSE;
                        /* reset the host_srcip so that it gets assigned in modecfg */
                        anyaddr(AF_INET, &c->spd.that.host_srcip);
                }

                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[BUF_LEN];

                        (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 freeing.
 */
char *add_group_instance(connection_t *group, const ip_subnet *target)
{
        char namebuf[100], targetbuf[SUBNETTOT_BUF];
        connection_t *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);
                t->name = namebuf;
                unshare_connection_strings(t);
                name = clone_str(t->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 connection_t *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_ANY), 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 connection_t *instantiate(connection_t *c, const ip_address *him,
                                                                 u_int16_t his_port, identification_t *his_id)
{
        connection_t *d;

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

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

        if (his_id)
        {
                d->spd.that.id = his_id;
                d->spd.that.has_id_wildcards = FALSE;
        }
        unshare_connection_strings(d);
        if (d->spd.this.groups)
        {
                d->spd.this.groups = d->spd.this.groups->get_ref(d->spd.this.groups);
        }
        if (d->spd.that.groups)
        {
                d->spd.that.groups = d->spd.that.groups->get_ref(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;
        }
}

connection_t *rw_instantiate(connection_t *c, const ip_address *him,
                                                         u_int16_t his_port, const ip_subnet *his_net,
                                                         identification_t *his_id)
{
        connection_t *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;
}

connection_t *oppo_instantiate(connection_t *c, const ip_address *him,
                                                           identification_t *his_id, struct gw_info *gw,
                                                           const ip_address *our_client USED_BY_DEBUG,
                                                           const ip_address *peer_client)
{
        connection_t *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[BUF_LEN];

                (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 connection_t *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.
 */
connection_t *find_connection_for_clients(struct spd_route **srp,
                                                                                  const ip_address *our_client,
                                                                                  const ip_address *peer_client,
                                                                                  int transport_proto)
{
        connection_t *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 && NEVER_NEGOTIATE(best->policy))
        {
                best = NULL;
        }
        if (srp && best)
        {
                *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.
 */
connection_t *build_outgoing_opportunistic_connection(struct gw_info *gw,
                                                                                        const ip_address *our_client,
                                                                                        const ip_address *peer_client)
{
        struct iface *p;
        connection_t *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));

        /* 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).
                 */
                connection_t *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
        {
                chunk_t encoding = gw->gw_id->get_encoding(gw->gw_id);
                id_type_t type   = gw->gw_id->get_type(gw->gw_id);
                ip_address ip_addr;

                initaddr(encoding.ptr, encoding.len,
                                (type == ID_IPV4_ADDR) ? AF_INET : AF_INET6, &ip_addr);

                return oppo_instantiate(best, &ip_addr, NULL, gw, our_client, peer_client);
        }
}

bool orient(connection_t *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)
{
        connection_t *c = con_by_name(name, TRUE);

        if (c && 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 && !c->spd.this.sc->valid && whackfd != NULL_FD)
                        {
                                scx_get_pin(c->spd.this.sc, whackfd);
                        }
                        if (c->spd.this.sc && !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(connection_t *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 && c->policy_next)
        {
                /* there is some policy that comes afterwards */
                struct spd_route *shunt_spd;
                connection_t *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_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! */
        connection_t *c;
        bool was_held = cr->b.held;
        int whackfd = cr->b.whackfd;

        /* note: cr->id has no resources; cr->sgw_id is ID_ANY:
         * 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)
        {
                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)
        {
                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 connection_t *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;
        private_key_t *private;
        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 ((private = get_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
                        && private->belongs_to(private, &kr->key->public_key))
                        {
                                ugh = NULL;     /* good! */
                                break;
                        }
                }
        }
        if (ugh)
        {
                myid_state = old_myid_state;
        }
        return ugh;
}
#endif /* USE_KEYRR */

static err_t check_txt_recs(enum myid_state try_state, const connection_t *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;
        private_key_t *private;
        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 ((private = get_private_key(c)) == NULL)
        {
                ugh = "we don't know our own RSA key";
        }
        else if (!ac->id->equals(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)
                {
                        public_key_t *pub_key = gwp->key->public_key;

                        ugh = "all our TXT RRs have the wrong public key";
                        if (pub_key->get_type(pub_key) == KEY_RSA &&
                            private->belongs_to(private, pub_key))
                        {
                                ugh = NULL;     /* good! */
                                break;
                        }
                }
        }
        if (ugh)
        {
                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)
{
        connection_t *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 = fos_myid_ip_txt;
                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)));
                snprintf(mycredentialstr, BUF_LEN, "%Y", sr->this.id);

                /* 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)
                        {
                                /* cannot use our IP as OE identitiy for initiation */
                                DBG(DBG_OPPO,
                                        DBG_log("can not use our IP (%Y:TXT) as identity: %s",
                                                        myids[MYID_IP], ugh));
                                if (!logged_myid_ip_txt_warning)
                                {
                                        loglog(RC_LOG_SERIOUS,
                                                        "can not use our IP (%Y:TXT) as identity: %s",
                                                        myids[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 (%Y:TXT) as identity!",
                                                        myids[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)
                        {
                                /* cannot use our hostname as OE identitiy for initiation */
                                DBG(DBG_OPPO,
                                        DBG_log("can not use our hostname (%Y:TXT) as identity: %s",
                                                        myids[MYID_HOSTNAME], ugh));
                                if (!logged_myid_fqdn_txt_warning)
                                {
                                        loglog(RC_LOG_SERIOUS,
                                                        "can not use our hostname (%Y:TXT) as identity: %s",
                                                        myids[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 (%Y:TXT) as identity!",
                                                        myids[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)
                        {
                                /* cannot use our IP as OE identitiy for initiation */
                                DBG(DBG_OPPO,
                                        DBG_log("can not use our IP (%Y:KEY) as identity: %s",
                                                        myids[MYID_IP], ugh));
                                if (!logged_myid_ip_key_warning)
                                {
                                        loglog(RC_LOG_SERIOUS,
                                                        "can not use our IP (%Y:KEY) as identity: %s",
                                                        myids[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 (%Y:KEY) as identity!",
                                                        myids[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)
                        {
                                /* cannot use our IP as OE identitiy for initiation */
                                DBG(DBG_OPPO,
                                        DBG_log("can not use our hostname (%Y:KEY) as identity: %s",
                                                        myids[MYID_HOSTNAME], ugh));
                                if (!logged_myid_fqdn_key_warning)
                                {
                                        loglog(RC_LOG_SERIOUS,
                                                        "can not use our hostname (%Y:KEY) as identity: %s",
                                                        myids[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 (%Y:KEY) as identity!",
                                                        myids[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.
                                 */
                                private_key_t *private = get_private_key(c);

                                next_step = fos_his_client;     /* normal situation */

                                if (private == 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 (!ac->sgw_id->equals(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)
                                        {
                                                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 (private->belongs_to(private, gwp->key->public_key))
                                                {
                                                        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.
                                 */
                                private_key_t *private = get_private_key(c);

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

                                if (private == NULL)
                                {
                                        ugh = "we don't know our own RSA key";
                                }
                                else if (!ac->id->equals(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)
                                        {
                                                ugh = "TXT RR for us has wrong key";
                                                if (gwp->gw_key_present &&
                                                        private->belongs_to(private, gwp->key->public_key))
                                                {
                                                        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)
                                        {
                                                /* 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.
                                 */
                                private_key_t *private = get_private_key(c);

                                next_step = fos_his_client;     /* always */

                                if (private == 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
                                                && private->belongs_to(private, kr->key->public_key))
                                                {
                                                        /* 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];

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

#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)
                {
                        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 = malloc_thing(struct find_oppo_continuation);
                        identification_t *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->get_type(c->spd.this.id) == 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->get_type(c->spd.this.id) == 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], 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], 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";
                                        id = identification_create_from_sockaddr((sockaddr_t*)&b->our_client);
                                        ugh = start_adns_query(id, c->spd.this.id, /* we are the security gateway */
                                                                                   T_TXT, continue_oppo, &cr->ac);
                                        id->destroy(id);
                                        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 */
                                                                           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, 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;
                                id = identification_create_from_sockaddr((sockaddr_t*)&b->peer_client);
                                ugh = start_adns_query(id, NULL, /* security gateway unconstrained */
                                                                           T_TXT, continue_oppo, &cr->ac);
                                id->destroy(id);
                                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).
         */
        connection_t *c = con_by_name(nm, TRUE);

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

        do
        {
                connection_t *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);
                        if (c->kind == CK_INSTANCE)
                                delete_connection(c, FALSE);
                        reset_cur_connection();
                }
                c = n;
        } while (c);
}

/* 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(connection_t *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.
                 */
                connection_t *d;

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

                        if (d->kind >= CK_PERMANENT &&
                                c->spd.this.id->equals(c->spd.this.id, d->spd.this.id) &&
                                c->spd.that.id->equals(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.
 */
connection_t *route_owner(connection_t *c, struct spd_route **srp,
                                                  connection_t **erop, struct spd_route **esrp)
{
        connection_t *d
                , *best_ro = c