[people/ms/strongswan.git] / src / pluto / kernel.c

/* routines that interface with the kernel's IPsec mechanism
 * Copyright (C) 1997 Angelos D. Keromytis.
 * Copyright (C) 1998-2002  D. Hugh Redelmeier.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * RCSID $Id: kernel.c,v 1.25 2006/04/17 14:58:09 as Exp $
 */

#include <stddef.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <wait.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/queue.h>

#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <freeswan.h>
#include <freeswan/ipsec_policy.h>

#ifdef KLIPS
#include <signal.h>
#include <sys/time.h>   /* for select(2) */
#include <sys/types.h>  /* for select(2) */
#include <pfkeyv2.h>
#include <pfkey.h>
#include "kameipsec.h"
#endif /* KLIPS */

#include "constants.h"
#include "defs.h"
#include "rnd.h"
#include "id.h"
#include "connections.h"
#include "state.h"
#include "timer.h"
#include "kernel.h"
#include "kernel_netlink.h"
#include "kernel_pfkey.h"
#include "kernel_noklips.h"
#include "log.h"
#include "ca.h"
#include "server.h"
#include "whack.h"      /* for RC_LOG_SERIOUS */
#include "keys.h"

#ifdef NAT_TRAVERSAL
#include "packet.h"  /* for pb_stream in nat_traversal.h */
#include "nat_traversal.h"
#endif

#include "alg_info.h"
#include "kernel_alg.h"


bool can_do_IPcomp = TRUE;  /* can system actually perform IPCOMP? */

/* How far can IPsec messages arrive out of order before the anti-replay
 * logic loses track and swats them?  64 is the best KLIPS can do.
 * And 32 is the best XFRM can do...
 */
#define REPLAY_WINDOW   64
#define REPLAY_WINDOW_XFRM      32

/* test if the routes required for two different connections agree
 * It is assumed that the destination subnets agree; we are only
 * testing that the interfaces and nexthops match.
 */
#define routes_agree(c, d) ((c)->interface == (d)->interface \
        && sameaddr(&(c)->spd.this.host_nexthop, &(d)->spd.this.host_nexthop))

#ifndef KLIPS

bool no_klips = TRUE;   /* don't actually use KLIPS */

#else /* !KLIPS */

/* bare (connectionless) shunt (eroute) table
 *
 * Bare shunts are those that don't "belong" to a connection.
 * This happens because some %trapped traffic hasn't yet or cannot be
 * assigned to a connection.  The usual reason is that we cannot discover
 * the peer SG.  Another is that even when the peer has been discovered,
 * it may be that no connection matches all the particulars.
 * We record them so that, with scanning, we can discover
 * which %holds are news and which others should expire.
 */

#define SHUNT_SCAN_INTERVAL     (60 * 2)   /* time between scans of eroutes */

/* SHUNT_PATIENCE only has resolution down to a multiple of the sample rate,
 * SHUNT_SCAN_INTERVAL.
 * By making SHUNT_PATIENCE an odd multiple of half of SHUNT_SCAN_INTERVAL,
 * we minimize the effects of jitter.
 */
#define SHUNT_PATIENCE  (SHUNT_SCAN_INTERVAL * 15 / 2)  /* inactivity timeout */

struct bare_shunt {
    policy_prio_t policy_prio;
    ip_subnet ours;
    ip_subnet his;
    ip_said said;
    int transport_proto;
    unsigned long count;
    time_t last_activity;
    char *why;
    struct bare_shunt *next;
};

static struct bare_shunt *bare_shunts = NULL;

#ifdef DEBUG
static void
DBG_bare_shunt(const char *op, const struct bare_shunt *bs)
{
    DBG(DBG_KLIPS,
        {
            int ourport = ntohs(portof(&(bs)->ours.addr));
            int hisport = ntohs(portof(&(bs)->his.addr));
            char ourst[SUBNETTOT_BUF];
            char hist[SUBNETTOT_BUF];
            char sat[SATOT_BUF];
            char prio[POLICY_PRIO_BUF];

            subnettot(&(bs)->ours, 0, ourst, sizeof(ourst));
            subnettot(&(bs)->his, 0, hist, sizeof(hist));
            satot(&(bs)->said, 0, sat, sizeof(sat));
            fmt_policy_prio(bs->policy_prio, prio);
            DBG_log("%s bare shunt %p %s:%d -> %s:%d => %s:%d %s    %s"
                , op, (const void *)(bs), ourst, ourport, hist, hisport
                , sat, (bs)->transport_proto, prio, (bs)->why);
        });
}
#else /* !DEBUG */
#define DBG_bare_shunt(op, bs) {}
#endif /* !DEBUG */

/* The orphaned_holds table records %holds for which we
 * scan_proc_shunts found no representation of in any connection.
 * The corresponding ACQUIRE message might have been lost.
 */
struct eroute_info *orphaned_holds = NULL;

/* forward declaration */
static bool shunt_eroute(struct connection *c
                         , struct spd_route *sr
                         , enum routing_t rt_kind
                         , unsigned int op, const char *opname);
static void set_text_said(char *text_said
                          , const ip_address *dst
                          , ipsec_spi_t spi
                          , int proto);

bool no_klips = FALSE;  /* don't actually use KLIPS */

static const struct pfkey_proto_info null_proto_info[2] = {
        {
                proto: IPPROTO_ESP,
                encapsulation: ENCAPSULATION_MODE_TRANSPORT,
                reqid: 0
        },
        {
                proto: 0,
                encapsulation: 0,
                reqid: 0
        }
};

void
record_and_initiate_opportunistic(const ip_subnet *ours
                                  , const ip_subnet *his
                                  , int transport_proto
                                  , const char *why)
{
    passert(samesubnettype(ours, his));

    /* Add to bare shunt list.
     * We need to do this because the shunt was installed by KLIPS
     * which can't do this itself.
     */
    {
        struct bare_shunt *bs = alloc_thing(struct bare_shunt, "bare shunt");

        bs->why = clone_str(why, "story for bare shunt");
        bs->ours = *ours;
        bs->his = *his;
        bs->transport_proto = transport_proto;
        bs->policy_prio = BOTTOM_PRIO;

        bs->said.proto = SA_INT;
        bs->said.spi = htonl(SPI_HOLD);
        bs->said.dst = *aftoinfo(subnettypeof(ours))->any;

        bs->count = 0;
        bs->last_activity = now();

        bs->next = bare_shunts;
        bare_shunts = bs;
        DBG_bare_shunt("add", bs);
    }

    /* actually initiate opportunism */
    {
        ip_address src, dst;

        networkof(ours, &src);
        networkof(his, &dst);
        initiate_opportunistic(&src, &dst, transport_proto, TRUE, NULL_FD);
    }

    /* if present, remove from orphaned_holds list.
     * NOTE: we do this last in case ours or his is a pointer into a member.
     */
    {
        struct eroute_info **pp, *p;

        for (pp = &orphaned_holds; (p = *pp) != NULL; pp = &p->next)
        {
            if (samesubnet(ours, &p->ours)
            && samesubnet(his, &p->his)
            && transport_proto == p->transport_proto
            && portof(&ours->addr) == portof(&p->ours.addr)
            && portof(&his->addr) == portof(&p->his.addr))
            {
                *pp = p->next;
                pfree(p);
                break;
            }
        }
    }
}

#endif /* KLIPS */

static unsigned get_proto_reqid(unsigned base, int proto)
{
    switch (proto)
    {
    default:
    case IPPROTO_COMP:
        base++;
        /* fall through */
    case IPPROTO_ESP:
        base++;
        /* fall through */
    case IPPROTO_AH:
        break;
    }

    return base;
}

/* Generate Unique SPI numbers.
 *
 * The specs say that the number must not be less than IPSEC_DOI_SPI_MIN.
 * Pluto generates numbers not less than IPSEC_DOI_SPI_OUR_MIN,
 * reserving numbers in between for manual keying (but we cannot so
 * restrict numbers generated by our peer).
 * XXX This should be replaced by a call to the kernel when
 * XXX we get an API.
 * The returned SPI is in network byte order.
 * We use a random number as the initial SPI so that there is
 * a good chance that different Pluto instances will choose
 * different SPIs.  This is good for two reasons.
 * - the keying material for the initiator and responder only
 *   differs if the SPIs differ.
 * - if Pluto is restarted, it would otherwise recycle the SPI
 *   numbers and confuse everything.  When the kernel generates
 *   SPIs, this will no longer matter.
 * We then allocate numbers sequentially.  Thus we don't have to
 * check if the number was previously used (assuming that no
 * SPI lives longer than 4G of its successors).
 */
ipsec_spi_t
get_ipsec_spi(ipsec_spi_t avoid, int proto, struct spd_route *sr, bool tunnel)
{
    static ipsec_spi_t spi = 0; /* host order, so not returned directly! */
    char text_said[SATOT_BUF];

    set_text_said(text_said, &sr->this.host_addr, 0, proto);

    if (kernel_ops->get_spi)
        return kernel_ops->get_spi(&sr->that.host_addr
            , &sr->this.host_addr, proto, tunnel
            , get_proto_reqid(sr->reqid, proto)
            , IPSEC_DOI_SPI_OUR_MIN, 0xffffffff
            , text_said);

    spi++;
    while (spi < IPSEC_DOI_SPI_OUR_MIN || spi == ntohl(avoid))
        get_rnd_bytes((u_char *)&spi, sizeof(spi));

    DBG(DBG_CONTROL,
        {
            ipsec_spi_t spi_net = htonl(spi);

            DBG_dump("generate SPI:", (u_char *)&spi_net, sizeof(spi_net));
        });

    return htonl(spi);
}

/* Generate Unique CPI numbers.
 * The result is returned as an SPI (4 bytes) in network order!
 * The real bits are in the nework-low-order 2 bytes.
 * Modelled on get_ipsec_spi, but range is more limited:
 * 256-61439.
 * If we can't find one easily, return 0 (a bad SPI,
 * no matter what order) indicating failure.
 */
ipsec_spi_t
get_my_cpi(struct spd_route *sr, bool tunnel)
{
    static cpi_t
        first_busy_cpi = 0,
        latest_cpi;
    char text_said[SATOT_BUF];

    set_text_said(text_said, &sr->this.host_addr, 0, IPPROTO_COMP);

    if (kernel_ops->get_spi)
        return kernel_ops->get_spi(&sr->that.host_addr
            , &sr->this.host_addr, IPPROTO_COMP, tunnel
            , get_proto_reqid(sr->reqid, IPPROTO_COMP)
            , IPCOMP_FIRST_NEGOTIATED, IPCOMP_LAST_NEGOTIATED
            , text_said);

    while (!(IPCOMP_FIRST_NEGOTIATED <= first_busy_cpi && first_busy_cpi < IPCOMP_LAST_NEGOTIATED))
    {
        get_rnd_bytes((u_char *)&first_busy_cpi, sizeof(first_busy_cpi));
        latest_cpi = first_busy_cpi;
    }

    latest_cpi++;

    if (latest_cpi == first_busy_cpi)
        find_my_cpi_gap(&latest_cpi, &first_busy_cpi);

    if (latest_cpi > IPCOMP_LAST_NEGOTIATED)
        latest_cpi = IPCOMP_FIRST_NEGOTIATED;

    return htonl((ipsec_spi_t)latest_cpi);
}

/* invoke the updown script to do the routing and firewall commands required
 *
 * The user-specified updown script is run.  Parameters are fed to it in
 * the form of environment variables.  All such environment variables
 * have names starting with "PLUTO_".
 *
 * The operation to be performed is specified by PLUTO_VERB.  This
 * verb has a suffix "-host" if the client on this end is just the
 * host; otherwise the suffix is "-client".  If the address family
 * of the host is IPv6, an extra suffix of "-v6" is added.
 *
 * "prepare-host" and "prepare-client" are used to delete a route
 * that may exist (due to forces outside of Pluto).  It is used to
 * prepare for pluto creating a route.
 *
 * "route-host" and "route-client" are used to install a route.
 * Since routing is based only on destination, the PLUTO_MY_CLIENT_*
 * values are probably of no use (using them may signify a bug).
 *
 * "unroute-host" and "unroute-client" are used to delete a route.
 * Since routing is based only on destination, the PLUTO_MY_CLIENT_*
 * values are probably of no use (using them may signify a bug).
 *
 * "up-host" and "up-client" are run when an eroute is added (not replaced).
 * They are useful for adjusting a firewall: usually for adding a rule
 * to let processed packets flow between clients.  Note that only
 * one eroute may exist for a pair of client subnets but inbound
 * IPsec SAs may persist without an eroute.
 *
 * "down-host" and "down-client" are run when an eroute is deleted.
 * They are useful for adjusting a firewall.
 */

#ifndef DEFAULT_UPDOWN
# define DEFAULT_UPDOWN "ipsec _updown"
#endif

static bool
do_command(struct connection *c, struct spd_route *sr, const char *verb)
{
    char cmd[1536];     /* arbitrary limit on shell command length */
    const char *verb_suffix;

    /* figure out which verb suffix applies */
    {
        const char *hs, *cs;

        switch (addrtypeof(&sr->this.host_addr))
        {
            case AF_INET:
                hs = "-host";
                cs = "-client";
                break;
            case AF_INET6:
                hs = "-host-v6";
                cs = "-client-v6";
                break;
            default:
                loglog(RC_LOG_SERIOUS, "unknown address family");
                return FALSE;
        }
        verb_suffix = subnetisaddr(&sr->this.client, &sr->this.host_addr)
            ? hs : cs;
    }

    /* form the command string */
    {
        char
            nexthop_str[sizeof("PLUTO_NEXT_HOP='' ") +ADDRTOT_BUF] = "",
            srcip_str[sizeof("PLUTO_MY_SOURCEIP='' ")+ADDRTOT_BUF] = "",
            me_str[ADDRTOT_BUF],
            myid_str[BUF_LEN],
            myclient_str[SUBNETTOT_BUF],
            myclientnet_str[ADDRTOT_BUF],
            myclientmask_str[ADDRTOT_BUF],
            peer_str[ADDRTOT_BUF],
            peerid_str[BUF_LEN],
            peerclient_str[SUBNETTOT_BUF],
            peerclientnet_str[ADDRTOT_BUF],
            peerclientmask_str[ADDRTOT_BUF],
            peerca_str[BUF_LEN],
            secure_myid_str[BUF_LEN] = "",
            secure_peerid_str[BUF_LEN] = "",
            secure_peerca_str[BUF_LEN] = "";
        ip_address ta;
        pubkey_list_t *p;

        if (addrbytesptr(&sr->this.host_nexthop, NULL)
        && !isanyaddr(&sr->this.host_nexthop))
        {
            char *n;

            strcpy(nexthop_str, "PLUTO_NEXT_HOP='");
            n = nexthop_str + strlen(nexthop_str);

            addrtot(&sr->this.host_nexthop, 0
                    ,n , sizeof(nexthop_str)-strlen(nexthop_str));
            strncat(nexthop_str, "' ", sizeof(nexthop_str));
        }

        if (addrbytesptr(&sr->this.host_srcip, NULL)
        && !isanyaddr(&sr->this.host_srcip))
        {
            char *n;

            strcpy(srcip_str, "PLUTO_MY_SOURCEIP='");
            n = srcip_str + strlen(srcip_str);

            addrtot(&sr->this.host_srcip, 0
                    ,n , sizeof(srcip_str)-strlen(srcip_str));
            strncat(srcip_str, "' ", sizeof(srcip_str));
        }

        addrtot(&sr->this.host_addr, 0, me_str, sizeof(me_str));
        idtoa(&sr->this.id, myid_str, sizeof(myid_str));
        escape_metachar(myid_str, secure_myid_str, sizeof(secure_myid_str));
        subnettot(&sr->this.client, 0, myclient_str, sizeof(myclientnet_str));
        networkof(&sr->this.client, &ta);
        addrtot(&ta, 0, myclientnet_str, sizeof(myclientnet_str));
        maskof(&sr->this.client, &ta);
        addrtot(&ta, 0, myclientmask_str, sizeof(myclientmask_str));

        addrtot(&sr->that.host_addr, 0, peer_str, sizeof(peer_str));
        idtoa(&sr->that.id, peerid_str, sizeof(peerid_str));
        escape_metachar(peerid_str, secure_peerid_str, sizeof(secure_peerid_str));
        subnettot(&sr->that.client, 0, peerclient_str, sizeof(peerclientnet_str));
        networkof(&sr->that.client, &ta);
        addrtot(&ta, 0, peerclientnet_str, sizeof(peerclientnet_str));
        maskof(&sr->that.client, &ta);
        addrtot(&ta, 0, peerclientmask_str, sizeof(peerclientmask_str));

        for (p = pubkeys; p != NULL; p = p->next)
        {
            pubkey_t *key = p->key;
            int pathlen;

            if (key->alg == PUBKEY_ALG_RSA && same_id(&sr->that.id, &key->id)
            && trusted_ca(key->issuer, sr->that.ca, &pathlen))
            {
                dntoa_or_null(peerca_str, BUF_LEN, key->issuer, "");
                escape_metachar(peerca_str, secure_peerca_str, sizeof(secure_peerca_str));
                break;
            }
        }

        if (-1 == snprintf(cmd, sizeof(cmd)
            , "2>&1 "   /* capture stderr along with stdout */
            "PLUTO_VERSION='1.1' "      /* change VERSION when interface spec changes */
            "PLUTO_VERB='%s%s' "
            "PLUTO_CONNECTION='%s' "
            "%s"        /* optional PLUTO_NEXT_HOP */
            "PLUTO_INTERFACE='%s' "
            "%s"        /* optional PLUTO_HOST_ACCESS */
            "PLUTO_REQID='%u' "
            "PLUTO_ME='%s' "
            "PLUTO_MY_ID='%s' "
            "PLUTO_MY_CLIENT='%s' "
            "PLUTO_MY_CLIENT_NET='%s' "
            "PLUTO_MY_CLIENT_MASK='%s' "
            "PLUTO_MY_PORT='%u' "
            "PLUTO_MY_PROTOCOL='%u' "
            "PLUTO_PEER='%s' "
            "PLUTO_PEER_ID='%s' "
            "PLUTO_PEER_CLIENT='%s' "
            "PLUTO_PEER_CLIENT_NET='%s' "
            "PLUTO_PEER_CLIENT_MASK='%s' "
            "PLUTO_PEER_PORT='%u' "
            "PLUTO_PEER_PROTOCOL='%u' "
            "PLUTO_PEER_CA='%s' "
            "%s"        /* optional PLUTO_MY_SRCIP */
            "%s"        /* actual script */
            , verb, verb_suffix
            , c->name
            , nexthop_str
            , c->interface->vname
            , sr->this.hostaccess? "PLUTO_HOST_ACCESS='1' " : ""
            , sr->reqid + 1     /* ESP requid */
            , me_str
            , secure_myid_str
            , myclient_str
            , myclientnet_str
            , myclientmask_str
            , sr->this.port
            , sr->this.protocol
            , peer_str
            , secure_peerid_str
            , peerclient_str
            , peerclientnet_str
            , peerclientmask_str
            , sr->that.port
            , sr->that.protocol
            , secure_peerca_str
            , srcip_str
            , sr->this.updown == NULL? DEFAULT_UPDOWN : sr->this.updown))
        {
            loglog(RC_LOG_SERIOUS, "%s%s command too long!", verb, verb_suffix);
            return FALSE;
        }
    }

    DBG(DBG_CONTROL, DBG_log("executing %s%s: %s"
        , verb, verb_suffix, cmd));

#ifdef KLIPS
    if (!no_klips)
    {
        /* invoke the script, catching stderr and stdout
         * It may be of concern that some file descriptors will
         * be inherited.  For the ones under our control, we
         * have done fcntl(fd, F_SETFD, FD_CLOEXEC) to prevent this.
         * Any used by library routines (perhaps the resolver or syslog)
         * will remain.
         */
        FILE *f = popen(cmd, "r");

        if (f == NULL)
        {
            loglog(RC_LOG_SERIOUS, "unable to popen %s%s command", verb, verb_suffix);
            return FALSE;
        }

        /* log any output */
        for (;;)
        {
            /* if response doesn't fit in this buffer, it will be folded */
            char resp[256];

            if (fgets(resp, sizeof(resp), f) == NULL)
            {
                if (ferror(f))
                {
                    log_errno((e, "fgets failed on output of %s%s command"
                        , verb, verb_suffix));
                    return FALSE;
                }
                else
                {
                    passert(feof(f));
                    break;
                }
            }
            else
            {
                char *e = resp + strlen(resp);

                if (e > resp && e[-1] == '\n')
                    e[-1] = '\0';       /* trim trailing '\n' */
                plog("%s%s output: %s", verb, verb_suffix, resp);
            }
        }

        /* report on and react to return code */
        {
            int r = pclose(f);

            if (r == -1)
            {
                log_errno((e, "pclose failed for %s%s command"
                    , verb, verb_suffix));
                return FALSE;
            }
            else if (WIFEXITED(r))
            {
                if (WEXITSTATUS(r) != 0)
                {
                    loglog(RC_LOG_SERIOUS, "%s%s command exited with status %d"
                        , verb, verb_suffix, WEXITSTATUS(r));
                    return FALSE;
                }
            }
            else if (WIFSIGNALED(r))
            {
                loglog(RC_LOG_SERIOUS, "%s%s command exited with signal %d"
                    , verb, verb_suffix, WTERMSIG(r));
                return FALSE;
            }
            else
            {
                loglog(RC_LOG_SERIOUS, "%s%s command exited with unknown status %d"
                    , verb, verb_suffix, r);
                return FALSE;
            }
        }
    }
#endif /* KLIPS */
    return TRUE;
}

/* Check that we can route (and eroute).  Diagnose if we cannot. */

enum routability {
    route_impossible = 0,
    route_easy = 1,
    route_nearconflict = 2,
    route_farconflict = 3
};

static enum routability
could_route(struct connection *c)
{
    struct spd_route *esr, *rosr;
    struct connection *ero      /* who, if anyone, owns our eroute? */
        , *ro = route_owner(c, &rosr, &ero, &esr); /* who owns our route? */

    /* it makes no sense to route a connection that is ISAKMP-only */
    if (!NEVER_NEGOTIATE(c->policy) && !HAS_IPSEC_POLICY(c->policy))
    {
        loglog(RC_ROUTE, "cannot route an ISAKMP-only connection");
        return route_impossible;
    }

    /* if this is a Road Warrior template, we cannot route.
     * Opportunistic template is OK.
     */
    if (c->kind == CK_TEMPLATE && !(c->policy & POLICY_OPPO))
    {
        loglog(RC_ROUTE, "cannot route Road Warrior template");
        return route_impossible;
    }

    /* if we don't know nexthop, we cannot route */
    if (isanyaddr(&c->spd.this.host_nexthop))
    {
        loglog(RC_ROUTE, "cannot route connection without knowing our nexthop");
        return route_impossible;
    }

    /* if routing would affect IKE messages, reject */
    if (!no_klips
#ifdef NAT_TRAVERSAL
    && c->spd.this.host_port != NAT_T_IKE_FLOAT_PORT
#endif
    && c->spd.this.host_port != IKE_UDP_PORT
    && addrinsubnet(&c->spd.that.host_addr, &c->spd.that.client))
    {
        loglog(RC_LOG_SERIOUS, "cannot install route: peer is within its client");
        return route_impossible;
    }

    /* If there is already a route for peer's client subnet
     * and it disagrees about interface or nexthop, we cannot steal it.
     * Note: if this connection is already routed (perhaps for another
     * state object), the route will agree.
     * This is as it should be -- it will arise during rekeying.
     */
    if (ro != NULL && !routes_agree(ro, c))
    {
        loglog(RC_LOG_SERIOUS, "cannot route -- route already in use for \"%s\""
            , ro->name);
        return route_impossible;  /* another connection already
                                     using the eroute */
    }

#ifdef KLIPS
    /* if there is an eroute for another connection, there is a problem */
    if (ero != NULL && ero != c)
    {
        struct connection *ero2, *ero_top;
        struct connection *inside, *outside;

        /*
         * note, wavesec (PERMANENT) goes *outside* and
         * OE goes *inside* (TEMPLATE)
         */
        inside = NULL;
        outside= NULL;
        if (ero->kind == CK_PERMANENT
           && c->kind == CK_TEMPLATE)
        {
            outside = ero;
            inside = c;
        }
        else if (c->kind == CK_PERMANENT
                && ero->kind == CK_TEMPLATE)
        {
            outside = c;
            inside = ero;
        }

        /* okay, check again, with correct order */
        if (outside && outside->kind == CK_PERMANENT
            && inside && inside->kind == CK_TEMPLATE)
        {
            char inst[CONN_INST_BUF];

            /* this is a co-terminal attempt of the "near" kind. */
            /* when chaining, we chain from inside to outside */

            /* XXX permit multiple deep connections? */
            passert(inside->policy_next == NULL);

            inside->policy_next = outside;

            /* since we are going to steal the eroute from the secondary
             * policy, we need to make sure that it no longer thinks that
             * it owns the eroute.
             */
            outside->spd.eroute_owner = SOS_NOBODY;
            outside->spd.routing = RT_UNROUTED_KEYED;

            /* set the priority of the new eroute owner to be higher
             * than that of the current eroute owner
             */
            inside->prio = outside->prio + 1;

            fmt_conn_instance(inside, inst);

            loglog(RC_LOG_SERIOUS
                   , "conflict on eroute (%s), switching eroute to %s and linking %s"
                   , inst, inside->name, outside->name);

            return route_nearconflict;
        }

        /* look along the chain of policies for one with the same name */
        ero_top = ero;

        for (ero2 = ero; ero2 != NULL; ero2 = ero->policy_next)
        {
            if (ero2->kind == CK_TEMPLATE
            && streq(ero2->name, c->name))
                break;
        }

        /* If we fell of the end of the list, then we found no TEMPLATE
         * so there must be a conflict that we can't resolve.
         * As the names are not equal, then we aren't replacing/rekeying.
         */
        if (ero2 == NULL)
        {
            char inst[CONN_INST_BUF];

            fmt_conn_instance(ero, inst);

            loglog(RC_LOG_SERIOUS
                , "cannot install eroute -- it is in use for \"%s\"%s #%lu"
                , ero->name, inst, esr->eroute_owner);
            return FALSE;       /* another connection already using the eroute */
        }
    }
#endif /* KLIPS */
    return route_easy;
}

bool
trap_connection(struct connection *c)
{
    switch (could_route(c))
    {
    case route_impossible:
        return FALSE;

    case route_nearconflict:
    case route_easy:
        /* RT_ROUTED_TUNNEL is treated specially: we don't override
         * because we don't want to lose track of the IPSEC_SAs etc.
         */
        if (c->spd.routing < RT_ROUTED_TUNNEL)
        {
            return route_and_eroute(c, &c->spd, NULL);
        }
        return TRUE;

    case route_farconflict:
        return FALSE;
    }

    return FALSE;
}

/* delete any eroute for a connection and unroute it if route isn't shared */
void
unroute_connection(struct connection *c)
{
    struct spd_route *sr;
    enum routing_t cr;

    for (sr = &c->spd; sr; sr = sr->next)
    {
        cr = sr->routing;

        if (erouted(cr))
        {
            /* cannot handle a live one */
            passert(sr->routing != RT_ROUTED_TUNNEL);
#ifdef KLIPS
            shunt_eroute(c, sr, RT_UNROUTED, ERO_DELETE, "delete");
#endif
        }

        sr->routing = RT_UNROUTED;  /* do now so route_owner won't find us */

        /* only unroute if no other connection shares it */
        if (routed(cr) && route_owner(c, NULL, NULL, NULL) == NULL)
            (void) do_command(c, sr, "unroute");
    }
}


#ifdef KLIPS

static void
set_text_said(char *text_said, const ip_address *dst, ipsec_spi_t spi, int proto)
{
    ip_said said;

    initsaid(dst, spi, proto, &said);
    satot(&said, 0, text_said, SATOT_BUF);
}

/* find an entry in the bare_shunt table.
 * Trick: return a pointer to the pointer to the entry;
 * this allows the entry to be deleted.
 */
static struct bare_shunt **
bare_shunt_ptr(const ip_subnet *ours, const ip_subnet *his, int transport_proto)
{
    struct bare_shunt *p, **pp;

    for (pp = &bare_shunts; (p = *pp) != NULL; pp = &p->next)
    {
        if (samesubnet(ours, &p->ours)
        && samesubnet(his, &p->his)
        && transport_proto == p->transport_proto
        && portof(&ours->addr) == portof(&p->ours.addr)
        && portof(&his->addr) == portof(&p->his.addr))
            return pp;
    }
    return NULL;
}

/* free a bare_shunt entry, given a pointer to the pointer */
static void
free_bare_shunt(struct bare_shunt **pp)
{
    if (pp == NULL)
    {
        DBG(DBG_CONTROL,
            DBG_log("delete bare shunt: null pointer")
        )
    }
    else
    {
        struct bare_shunt *p = *pp;

        *pp = p->next;
        DBG_bare_shunt("delete", p);
        pfree(p->why);
        pfree(p);
    }
}

void
show_shunt_status(void)
{
    struct bare_shunt *bs;

    for (bs = bare_shunts; bs != NULL; bs = bs->next)
    {
        /* Print interesting fields.  Ignore count and last_active. */

        int ourport = ntohs(portof(&bs->ours.addr));
        int hisport = ntohs(portof(&bs->his.addr));
        char ourst[SUBNETTOT_BUF];
        char hist[SUBNETTOT_BUF];
        char sat[SATOT_BUF];
        char prio[POLICY_PRIO_BUF];

        subnettot(&(bs)->ours, 0, ourst, sizeof(ourst));
        subnettot(&(bs)->his, 0, hist, sizeof(hist));
        satot(&(bs)->said, 0, sat, sizeof(sat));
        fmt_policy_prio(bs->policy_prio, prio);

        whack_log(RC_COMMENT, "%s:%d -> %s:%d => %s:%d %s    %s"
            , ourst, ourport, hist, hisport, sat, bs->transport_proto
            , prio, bs->why);
    }
}

/* Setup an IPsec route entry.
 * op is one of the ERO_* operators.
 */

static bool
raw_eroute(const ip_address *this_host
           , const ip_subnet *this_client
           , const ip_address *that_host
           , const ip_subnet *that_client
           , ipsec_spi_t spi
           , unsigned int proto
           , unsigned int satype
           , unsigned int transport_proto
           , const struct pfkey_proto_info *proto_info
           , time_t use_lifetime
           , unsigned int op
           , const char *opname USED_BY_DEBUG)
{
    char text_said[SATOT_BUF];

    set_text_said(text_said, that_host, spi, proto);

    DBG(DBG_CONTROL | DBG_KLIPS,
        {
            int sport = ntohs(portof(&this_client->addr));
            int dport = ntohs(portof(&that_client->addr));
            char mybuf[SUBNETTOT_BUF];
            char peerbuf[SUBNETTOT_BUF];

            subnettot(this_client, 0, mybuf, sizeof(mybuf));
            subnettot(that_client, 0, peerbuf, sizeof(peerbuf));
            DBG_log("%s eroute %s:%d -> %s:%d => %s:%d"
                , opname, mybuf, sport, peerbuf, dport
                , text_said, transport_proto);
        });

    return kernel_ops->raw_eroute(this_host, this_client
        , that_host, that_client, spi, satype, transport_proto, proto_info
        , use_lifetime, op, text_said);
}

/* test to see if %hold remains */
bool
has_bare_hold(const ip_address *src, const ip_address *dst, int transport_proto)
{
    ip_subnet this_client, that_client;
    struct bare_shunt **bspp;

    passert(addrtypeof(src) == addrtypeof(dst));
    happy(addrtosubnet(src, &this_client));
    happy(addrtosubnet(dst, &that_client));
    bspp = bare_shunt_ptr(&this_client, &that_client, transport_proto);
    return bspp != NULL
        && (*bspp)->said.proto == SA_INT && (*bspp)->said.spi == htonl(SPI_HOLD);
}


/* Replace (or delete) a shunt that is in the bare_shunts table.
 * Issues the PF_KEY commands and updates the bare_shunts table.
 */
bool
replace_bare_shunt(const ip_address *src, const ip_address *dst
                   , policy_prio_t policy_prio
                   , ipsec_spi_t shunt_spi      /* in host order! */
                   , bool repl  /* if TRUE, replace; if FALSE, delete */
                   , unsigned int transport_proto
                   , const char *why)
{
    ip_subnet this_client, that_client;
    ip_subnet this_broad_client, that_broad_client;
    const ip_address *null_host = aftoinfo(addrtypeof(src))->any;

    passert(addrtypeof(src) == addrtypeof(dst));
    happy(addrtosubnet(src, &this_client));
    happy(addrtosubnet(dst, &that_client));
    this_broad_client = this_client;
    that_broad_client = that_client;
    setportof(0, &this_broad_client.addr);
    setportof(0, &that_broad_client.addr);

    if (repl)
    {
        struct bare_shunt **bs_pp = bare_shunt_ptr(&this_broad_client
                                                 , &that_broad_client, 0);

        /* is there already a broad host-to-host bare shunt? */
        if (bs_pp == NULL)
        {
            if (raw_eroute(null_host, &this_broad_client, null_host, &that_broad_client
                           , htonl(shunt_spi), SA_INT, SADB_X_SATYPE_INT
                           , 0, null_proto_info
                           , SHUNT_PATIENCE, ERO_ADD, why))
            {
                struct bare_shunt *bs = alloc_thing(struct bare_shunt, "bare shunt");

                bs->ours = this_broad_client;
                bs->his =  that_broad_client;
                bs->transport_proto = 0;
                bs->said.proto = SA_INT;
                bs->why = clone_str(why, "bare shunt story");
                bs->policy_prio = policy_prio;
                bs->said.spi = htonl(shunt_spi);
                bs->said.dst = *null_host;
                bs->count = 0;
                bs->last_activity = now();
                bs->next = bare_shunts;
                bare_shunts = bs;
                DBG_bare_shunt("add", bs);
            }
        }
        shunt_spi = SPI_HOLD;
    }

    if (raw_eroute(null_host, &this_client, null_host, &that_client
                   , htonl(shunt_spi), SA_INT, SADB_X_SATYPE_INT
                   , transport_proto, null_proto_info
                   , SHUNT_PATIENCE, ERO_DELETE, why))
    {
        struct bare_shunt **bs_pp = bare_shunt_ptr(&this_client, &that_client
                                        , transport_proto);

        /* delete bare eroute */
        free_bare_shunt(bs_pp);
        return TRUE;
    }
    else
    {
        return FALSE;
    }
}

static bool
eroute_connection(struct spd_route *sr
, ipsec_spi_t spi, unsigned int proto, unsigned int satype
, const struct pfkey_proto_info *proto_info
, unsigned int op, const char *opname)
{
    const ip_address *peer = &sr->that.host_addr;
    char buf2[256];

    snprintf(buf2, sizeof(buf2)
             , "eroute_connection %s", opname);

    if (proto == SA_INT)
        peer = aftoinfo(addrtypeof(peer))->any;

    return raw_eroute(&sr->this.host_addr, &sr->this.client
                      , peer
                      , &sr->that.client
                      , spi, proto, satype
                      , sr->this.protocol, proto_info, 0, op, buf2);
}

/* assign a bare hold to a connection */

bool
assign_hold(struct connection *c USED_BY_DEBUG
            , struct spd_route *sr
            , int transport_proto
            , const ip_address *src, const ip_address *dst)
{
    /* either the automatically installed %hold eroute is broad enough
     * or we try to add a broader one and delete the automatic one.
     * Beware: this %hold might be already handled, but still squeak
     * through because of a race.
     */
    enum routing_t ro = sr->routing     /* routing, old */
        , rn = ro;                      /* routing, new */

    passert(LHAS(LELEM(CK_PERMANENT) | LELEM(CK_INSTANCE), c->kind));
    /* figure out what routing should become */
    switch (ro)
    {
    case RT_UNROUTED:
        rn = RT_UNROUTED_HOLD;
        break;
    case RT_ROUTED_PROSPECTIVE:
        rn = RT_ROUTED_HOLD;
        break;
    default:
        /* no change: this %hold is old news and should just be deleted */
        break;
    }

    /* we need a broad %hold, not the narrow one.
     * First we ensure that there is a broad %hold.
     * There may already be one (race condition): no need to create one.
     * There may already be a %trap: replace it.
     * There may not be any broad eroute: add %hold.
     * Once the broad %hold is in place, delete the narrow one.
     */
    if (rn != ro)
    {
        if (erouted(ro)
        ? !eroute_connection(sr, htonl(SPI_HOLD), SA_INT, SADB_X_SATYPE_INT
                , null_proto_info
                , ERO_REPLACE, "replace %trap with broad %hold")
        : !eroute_connection(sr, htonl(SPI_HOLD), SA_INT, SADB_X_SATYPE_INT
                , null_proto_info
                , ERO_ADD, "add broad %hold"))
        {
            return FALSE;
        }
    }
    if (!replace_bare_shunt(src, dst, BOTTOM_PRIO, SPI_HOLD, FALSE
    , transport_proto, "delete narrow %hold"))
    {
        return FALSE;
    }
    sr->routing = rn;
    return TRUE;
}

/* install or remove eroute for SA Group */
static bool
sag_eroute(struct state *st, struct spd_route *sr
           , unsigned op, const char *opname)
{
    u_int inner_proto = 0;
    u_int inner_satype = 0;
    ipsec_spi_t inner_spi = 0;
    struct pfkey_proto_info proto_info[4];
    int i;
    bool tunnel;

    /* figure out the SPI and protocol (in two forms)
     * for the innermost transformation.
     */

    i = sizeof(proto_info) / sizeof(proto_info[0]) - 1;
    proto_info[i].proto = 0;
    tunnel = FALSE;

    if (st->st_ah.present)
    {
        inner_spi = st->st_ah.attrs.spi;
        inner_proto = SA_AH;
        inner_satype = SADB_SATYPE_AH;

        i--;
        proto_info[i].proto = IPPROTO_AH;
        proto_info[i].encapsulation = st->st_ah.attrs.encapsulation;
        tunnel |= proto_info[i].encapsulation == ENCAPSULATION_MODE_TUNNEL;
        proto_info[i].reqid = sr->reqid;
    }

    if (st->st_esp.present)
    {
        inner_spi = st->st_esp.attrs.spi;
        inner_proto = SA_ESP;
        inner_satype = SADB_SATYPE_ESP;

        i--;
        proto_info[i].proto = IPPROTO_ESP;
        proto_info[i].encapsulation = st->st_esp.attrs.encapsulation;
        tunnel |= proto_info[i].encapsulation == ENCAPSULATION_MODE_TUNNEL;
        proto_info[i].reqid = sr->reqid + 1;
    }

    if (st->st_ipcomp.present)
    {
        inner_spi = st->st_ipcomp.attrs.spi;
        inner_proto = SA_COMP;
        inner_satype = SADB_X_SATYPE_COMP;

        i--;
        proto_info[i].proto = IPPROTO_COMP;
        proto_info[i].encapsulation = st->st_ipcomp.attrs.encapsulation;
        tunnel |= proto_info[i].encapsulation == ENCAPSULATION_MODE_TUNNEL;
        proto_info[i].reqid = sr->reqid + 2;
    }

    if (i == sizeof(proto_info) / sizeof(proto_info[0]) - 1)
    {
        impossible();   /* no transform at all! */
    }

    if (tunnel)
    {
        int j;

        inner_spi = st->st_tunnel_out_spi;
        inner_proto = SA_IPIP;
        inner_satype = SADB_X_SATYPE_IPIP;

        proto_info[i].encapsulation = ENCAPSULATION_MODE_TUNNEL;
        for (j = i + 1; proto_info[j].proto; j++)
        {
            proto_info[j].encapsulation = ENCAPSULATION_MODE_TRANSPORT;
        }
    }

    return eroute_connection(sr
        , inner_spi, inner_proto, inner_satype, proto_info + i
        , op, opname);
}

/* compute a (host-order!) SPI to implement the policy in connection c */
ipsec_spi_t
shunt_policy_spi(struct connection *c, bool prospective)
{
    /* note: these are in host order :-( */
    static const ipsec_spi_t shunt_spi[] =
    {
        SPI_TRAP,       /* --initiateontraffic */
        SPI_PASS,       /* --pass */
        SPI_DROP,       /* --drop */
        SPI_REJECT,     /* --reject */
    };

    static const ipsec_spi_t fail_spi[] =
    {
        0,      /* --none*/
        SPI_PASS,       /* --failpass */
        SPI_DROP,       /* --faildrop */
        SPI_REJECT,     /* --failreject */
    };

    return prospective
        ? shunt_spi[(c->policy & POLICY_SHUNT_MASK) >> POLICY_SHUNT_SHIFT]
        : fail_spi[(c->policy & POLICY_FAIL_MASK) >> POLICY_FAIL_SHIFT];
}

/* Add/replace/delete a shunt eroute.
 * Such an eroute determines the fate of packets without the use
 * of any SAs.  These are defaults, in effect.
 * If a negotiation has not been attempted, use %trap.
 * If negotiation has failed, the choice between %trap/%pass/%drop/%reject
 * is specified in the policy of connection c.
 */
static bool
shunt_eroute(struct connection *c
, struct spd_route *sr
, enum routing_t rt_kind
, unsigned int op, const char *opname)
{
    /* We are constructing a special SAID for the eroute.
     * The destination doesn't seem to matter, but the family does.
     * The protocol is SA_INT -- mark this as shunt.
     * The satype has no meaning, but is required for PF_KEY header!
     * The SPI signifies the kind of shunt.
     */
    ipsec_spi_t spi = shunt_policy_spi(c, rt_kind == RT_ROUTED_PROSPECTIVE);
    bool ok;

    if (spi == 0)
    {
        /* we're supposed to end up with no eroute: rejig op and opname */
        switch (op)
        {
        case ERO_REPLACE:
            /* replace with nothing == delete */
            op = ERO_DELETE;
            opname = "delete";
            break;
        case ERO_ADD:
            /* add nothing == do nothing */
            return TRUE;
        case ERO_DELETE:
            /* delete remains delete */
            break;
        default:
            bad_case(op);
        }
    }
    if (sr->routing == RT_ROUTED_ECLIPSED && c->kind == CK_TEMPLATE)
    {
        /* We think that we have an eroute, but we don't.
         * Adjust the request and account for eclipses.
         */
        passert(eclipsable(sr));
        switch (op)
        {
        case ERO_REPLACE:
            /* really an add */
            op = ERO_ADD;
            opname = "replace eclipsed";
            eclipse_count--;
            break;
        case ERO_DELETE:
            /* delete unnecessary: we don't actually have an eroute */
            eclipse_count--;
            return TRUE;
        case ERO_ADD:
        default:
            bad_case(op);
        }
    }
    else if (eclipse_count > 0 && op == ERO_DELETE && eclipsable(sr))
    {
        /* maybe we are uneclipsing something */
        struct spd_route *esr;
        struct connection *ue = eclipsed(c, &esr);

        if (ue != NULL)
        {
            esr->routing = RT_ROUTED_PROSPECTIVE;
            return shunt_eroute(ue, esr
                                , RT_ROUTED_PROSPECTIVE, ERO_REPLACE, "restoring eclipsed");
        }
    }

    ok = TRUE;
    if (kernel_ops->inbound_eroute)
    {
        ok = raw_eroute(&c->spd.that.host_addr, &c->spd.that.client
            , &c->spd.this.host_addr, &c->spd.this.client
            , htonl(spi), SA_INT, SADB_X_SATYPE_INT
            , 0, null_proto_info, 0
            , op | (SADB_X_SAFLAGS_INFLOW << ERO_FLAG_SHIFT), opname);
    }
    return eroute_connection(sr, htonl(spi), SA_INT, SADB_X_SATYPE_INT
        , null_proto_info, op, opname) && ok;
}


/*
 * This is only called when s is a likely SAID with  trailing protocol i.e.
 * it has the form :-
 *
 *   %<keyword>:p
 *   <ip-proto><spi>@a.b.c.d:p
 *
 * The task here is to remove the ":p" part so that the rest can be read
 * by another routine.
 */
static const char *
read_proto(const char * s, size_t * len, int * transport_proto)
{
    const char * p;
    const char * ugh;
    unsigned long proto;
    size_t l;

    l = *len;
    p = memchr(s, ':', l);
    if (p == 0) {
        *transport_proto = 0;
        return 0;
    }
    ugh = ttoul(p+1, l-((p-s)+1), 10, &proto);
    if (ugh != 0)
        return ugh;
    if (proto > 65535)
        return "protocol number is too large, legal range is 0-65535";
    *len = p-s;
    *transport_proto = proto;
    return 0;
}


/* scan /proc/net/ipsec_eroute every once in a while, looking for:
 *
 * - %hold shunts of which Pluto isn't aware.  This situation could
 *   be caused by lost ACQUIRE messages.  When found, they will
 *   added to orphan_holds.  This in turn will lead to Opportunistic
 *   initiation.
 *
 * - other kinds of shunts that haven't been used recently.  These will be
 *   deleted.  They represent OE failures.
 *
 * - recording recent uses of tunnel eroutes so that rekeying decisions
 *   can be made for OE connections.
 *
 * Here are some sample lines:
 * 10         10.3.2.1.0/24    -> 0.0.0.0/0          => %trap
 * 259        10.3.2.1.115/32  -> 10.19.75.161/32    => tun0x1002@10.19.75.145
 * 71         10.44.73.97/32   -> 0.0.0.0/0          => %trap
 * 4119       10.44.73.97/32   -> 10.114.121.41/32   => %pass
 * Newer versions of KLIPS start each line with a 32-bit packet count.
 * If available, the count is used to detect whether a %pass shunt is in use.
 *
 * NOTE: execution time is quadratic in the number of eroutes since the
 * searching for each is sequential.  If this becomes a problem, faster
 * searches could be implemented (hash or radix tree, for example).
 */
void
scan_proc_shunts(void)
{
    static const char procname[] = "/proc/net/ipsec_eroute";
    FILE *f;
    time_t nw = now();
    int lino;
    struct eroute_info *expired = NULL;

    event_schedule(EVENT_SHUNT_SCAN, SHUNT_SCAN_INTERVAL, NULL);

    DBG(DBG_CONTROL,
        DBG_log("scanning for shunt eroutes")
    )

    /* free any leftover entries: they will be refreshed if still current */
    while (orphaned_holds != NULL)
    {
        struct eroute_info *p = orphaned_holds;

        orphaned_holds = p->next;
        pfree(orphaned_holds);
    }

    /* decode the /proc file.  Don't do anything strenuous to it
     * (certainly no PF_KEY stuff) to minimize the chance that it
     * might change underfoot.
     */

    f = fopen(procname, "r");
    if (f == NULL)
        return;

    /* for each line... */
    for (lino = 1; ; lino++)
    {
        unsigned char buf[1024];  /* should be big enough */
        chunk_t field[10];        /* 10 is loose upper bound */
        chunk_t *ff = NULL;       /* fixed fields (excluding optional count) */
        int fi;
        struct eroute_info eri;
        char *cp;
        err_t context = ""
            , ugh = NULL;

        cp = fgets(buf, sizeof(buf), f);
        if (cp == NULL)
            break;

        /* break out each field
         * Note: if there are too many fields, just stop;
         * it will be diagnosed a little later.
         */
        for (fi = 0; fi < (int)elemsof(field); fi++)
        {
            static const char sep[] = " \t\n";  /* field-separating whitespace */
            size_t w;

            cp += strspn(cp, sep);      /* find start of field */
            w = strcspn(cp, sep);       /* find width of field */
            setchunk(field[fi], cp, w);
            cp += w;
            if (w == 0)
                break;
        }

        /* This odd do-hickey is to share error reporting code.
         * A break will get to that common code.  The setting
         * of "ugh" and "context" parameterize it.
         */
        do {
            /* Old entries have no packet count; new ones do.
             * check if things are as they should be.
             */
            if (fi == 5)
                ff = &field[0]; /* old form, with no count */
            else if (fi == 6)
                ff = &field[1]; /* new form, with count */
            else
            {
                ugh = "has wrong number of fields";
                break;
            }

            if (ff[1].len != 2
            || strncmp(ff[1].ptr, "->", 2) != 0
            || ff[3].len != 2
            || strncmp(ff[3].ptr, "=>", 2) != 0)
            {
                ugh = "is missing -> or =>";
                break;
            }

            /* actually digest fields of interest */

            /* packet count */

            eri.count = 0;
            if (ff != field)
            {
                context = "count field is malformed: ";
                ugh = ttoul(field[0].ptr, field[0].len, 10, &eri.count);
                if (ugh != NULL)
                    break;
            }

            /* our client */

            context = "source subnet field malformed: ";
            ugh = ttosubnet(ff[0].ptr, ff[0].len, AF_INET, &eri.ours);
            if (ugh != NULL)
                break;

            /* his client */

            context = "destination subnet field malformed: ";
            ugh = ttosubnet(ff[2].ptr, ff[2].len, AF_INET, &eri.his);
            if (ugh != NULL)
                break;

            /* SAID */

            context = "SA ID field malformed: ";
            ugh = read_proto(ff[4].ptr, &ff[4].len, &eri.transport_proto);
            if (ugh != NULL)
                break;
            ugh = ttosa(ff[4].ptr, ff[4].len, &eri.said);
        } while (FALSE);

        if (ugh != NULL)
        {
            plog("INTERNAL ERROR: %s line %d %s%s"
                , procname, lino, context, ugh);
            continue;   /* ignore rest of line */
        }

        /* Now we have decoded eroute, let's consider it.
         * For shunt eroutes:
         *
         * %hold: if not known, add to orphaned_holds list for initiation
         *    because ACQUIRE might have been lost.
         *
         * %pass, %drop, %reject: determine if idle; if so, blast it away.
         *    Can occur bare (if DNS provided insufficient information)
         *    or with a connection (failure context).
         *    Could even be installed by ipsec manual.
         *
         * %trap: always welcome.
         *
         * For other eroutes: find state and record count change
         */
        if (eri.said.proto == SA_INT)
        {
            /* shunt eroute */
            switch (ntohl(eri.said.spi))
            {
            case SPI_HOLD:
                if (bare_shunt_ptr(&eri.ours, &eri.his, eri.transport_proto) == NULL
                && shunt_owner(&eri.ours, &eri.his) == NULL)
                {
                    int ourport = ntohs(portof(&eri.ours.addr));
                    int hisport = ntohs(portof(&eri.his.addr));
                    char ourst[SUBNETTOT_BUF];
                    char hist[SUBNETTOT_BUF];
                    char sat[SATOT_BUF];

                    subnettot(&eri.ours, 0, ourst, sizeof(ourst));
                    subnettot(&eri.his, 0, hist, sizeof(hist));
                    satot(&eri.said, 0, sat, sizeof(sat));

                    DBG(DBG_CONTROL,
                        DBG_log("add orphaned shunt %s:%d -> %s:%d => %s:%d"
                            , ourst, ourport, hist, hisport, sat, eri.transport_proto)
                     )
                    eri.next = orphaned_holds;
                    orphaned_holds = clone_thing(eri, "orphaned %hold");
                }
                break;

            case SPI_PASS:
            case SPI_DROP:
            case SPI_REJECT:
                /* nothing sensible to do if we don't have counts */
                if (ff != field)
                {
                    struct bare_shunt **bs_pp
                        = bare_shunt_ptr(&eri.ours, &eri.his, eri.transport_proto);

                    if (bs_pp != NULL)
                    {
                        struct bare_shunt *bs = *bs_pp;

                        if (eri.count != bs->count)
                        {
                            bs->count = eri.count;
                            bs->last_activity = nw;
                        }
                        else if (nw - bs->last_activity > SHUNT_PATIENCE)
                        {
                            eri.next = expired;
                            expired = clone_thing(eri, "expired %pass");
                        }
                    }
                }
                break;

            case SPI_TRAP:
                break;

            default:
                bad_case(ntohl(eri.said.spi));
            }
        }
        else
        {
            /* regular (non-shunt) eroute */
            state_eroute_usage(&eri.ours, &eri.his, eri.count, nw);
        }
    }   /* for each line */
    fclose(f);

    /* Now that we've finished processing the /proc file,
     * it is safe to delete the expired %pass shunts.
     */
    while (expired != NULL)
    {
        struct eroute_info *p = expired;
        ip_address src, dst;

        networkof(&p->ours, &src);
        networkof(&p->his, &dst);
        (void) replace_bare_shunt(&src, &dst
            , BOTTOM_PRIO       /* not used because we are deleting.  This value is a filler */
            , SPI_PASS  /* not used because we are deleting.  This value is a filler */
            , FALSE, p->transport_proto, "delete expired bare shunts");
        expired = p->next;
        pfree(p);
    }
}

static bool
del_spi(ipsec_spi_t spi, int proto
, const ip_address *src, const ip_address *dest)
{
    char text_said[SATOT_BUF];
    struct kernel_sa sa;

    set_text_said(text_said, dest, spi, proto);

    DBG(DBG_KLIPS, DBG_log("delete %s", text_said));

    memset(&sa, 0, sizeof(sa));
    sa.spi = spi;
    sa.proto = proto;
    sa.src = src;
    sa.dst = dest;
    sa.text_said = text_said;

    return kernel_ops->del_sa(&sa);
}

/* Setup a pair of SAs. Code taken from setsa.c and spigrp.c, in
 * ipsec-0.5.
 */

static bool
setup_half_ipsec_sa(struct state *st, bool inbound)
{
    /* Build an inbound or outbound SA */

    struct connection *c = st->st_connection;
    ip_subnet src, dst;
    ip_subnet src_client, dst_client;
    ipsec_spi_t inner_spi = 0;
    u_int proto = 0;
    u_int satype = SADB_SATYPE_UNSPEC;
    bool replace;

    /* SPIs, saved for spigrouping or undoing, if necessary */
    struct kernel_sa
        said[EM_MAXRELSPIS],
        *said_next = said;

    char text_said[SATOT_BUF];
    int encapsulation;

    replace = inbound && (kernel_ops->get_spi != NULL);

    src.maskbits = 0;
    dst.maskbits = 0;

    if (inbound)
    {
        src.addr = c->spd.that.host_addr;
        dst.addr = c->spd.this.host_addr;
        src_client = c->spd.that.client;
        dst_client = c->spd.this.client;
    }
    else
    {
        src.addr = c->spd.this.host_addr,
        dst.addr = c->spd.that.host_addr;
        src_client = c->spd.this.client;
        dst_client = c->spd.that.client;
    }

    encapsulation = ENCAPSULATION_MODE_TRANSPORT;
    if (st->st_ah.attrs.encapsulation == ENCAPSULATION_MODE_TUNNEL
        || st->st_esp.attrs.encapsulation == ENCAPSULATION_MODE_TUNNEL
        || st->st_ipcomp.attrs.encapsulation == ENCAPSULATION_MODE_TUNNEL)
    {
        encapsulation = ENCAPSULATION_MODE_TUNNEL;
    }

    memset(said, 0, sizeof(said));

    /* If we are tunnelling, set up IP in IP pseudo SA */

    if (kernel_ops->inbound_eroute)
    {
        inner_spi = 256;
        proto = SA_IPIP;
        satype = SADB_SATYPE_UNSPEC;
    }
    else if (encapsulation == ENCAPSULATION_MODE_TUNNEL)
    {
        /* XXX hack alert -- we SHOULD NOT HAVE TO HAVE A DIFFERENT SPI
         * XXX FOR IP-in-IP ENCAPSULATION!
         */

        ipsec_spi_t ipip_spi;

        /* Allocate an SPI for the tunnel.
         * Since our peer will never see this,
         * and it comes from its own number space,
         * it is purely a local implementation wart.
         */
        {
            static ipsec_spi_t last_tunnel_spi = IPSEC_DOI_SPI_OUR_MIN;

            ipip_spi = htonl(++last_tunnel_spi);
            if (inbound)
                st->st_tunnel_in_spi = ipip_spi;
            else
                st->st_tunnel_out_spi = ipip_spi;
        }

        set_text_said(text_said
            , &c->spd.that.host_addr, ipip_spi, SA_IPIP);

        said_next->src = &src.addr;
        said_next->dst = &dst.addr;
        said_next->src_client = &src_client;
        said_next->dst_client = &dst_client;
        said_next->spi = ipip_spi;
        said_next->satype = SADB_X_SATYPE_IPIP;
        said_next->text_said = text_said;

        if (!kernel_ops->add_sa(said_next, replace))
            goto fail;

        said_next++;

        inner_spi = ipip_spi;
        proto = SA_IPIP;
        satype = SADB_X_SATYPE_IPIP;
    }

    /* set up IPCOMP SA, if any */

    if (st->st_ipcomp.present)
    {
        ipsec_spi_t ipcomp_spi = inbound? st->st_ipcomp.our_spi : st->st_ipcomp.attrs.spi;
        unsigned compalg;

        switch (st->st_ipcomp.attrs.transid)
        {
            case IPCOMP_DEFLATE:
                compalg = SADB_X_CALG_DEFLATE;
                break;

            default:
                loglog(RC_LOG_SERIOUS, "IPCOMP transform %s not implemented"
                    , enum_name(&ipcomp_transformid_names, st->st_ipcomp.attrs.transid));
                goto fail;
        }

        set_text_said(text_said, &dst.addr, ipcomp_spi, SA_COMP);

        said_next->src = &src.addr;
        said_next->dst = &dst.addr;
        said_next->src_client = &src_client;
        said_next->dst_client = &dst_client;
        said_next->spi = ipcomp_spi;
        said_next->satype = SADB_X_SATYPE_COMP;
        said_next->compalg = compalg;
        said_next->encapsulation = encapsulation;
        said_next->reqid = c->spd.reqid + 2;
        said_next->text_said = text_said;

        if (!kernel_ops->add_sa(said_next, replace))
            goto fail;

        said_next++;

        encapsulation = ENCAPSULATION_MODE_TRANSPORT;
    }

    /* set up ESP SA, if any */

    if (st->st_esp.present)
    {
        ipsec_spi_t esp_spi = inbound? st->st_esp.our_spi : st->st_esp.attrs.spi;
        u_char *esp_dst_keymat = inbound? st->st_esp.our_keymat : st->st_esp.peer_keymat;
        const struct esp_info *ei;
        u_int16_t key_len;

        static const struct esp_info esp_info[] = {
            { ESP_NULL, AUTH_ALGORITHM_HMAC_MD5,
                0, HMAC_MD5_KEY_LEN,
                SADB_EALG_NULL, SADB_AALG_MD5_HMAC },
            { ESP_NULL, AUTH_ALGORITHM_HMAC_SHA1,
                0, HMAC_SHA1_KEY_LEN,
                SADB_EALG_NULL, SADB_AALG_SHA1_HMAC },

            { ESP_DES, AUTH_ALGORITHM_NONE,
                DES_CBC_BLOCK_SIZE, 0,
                SADB_EALG_DES_CBC, SADB_AALG_NONE },
            { ESP_DES, AUTH_ALGORITHM_HMAC_MD5,
                DES_CBC_BLOCK_SIZE, HMAC_MD5_KEY_LEN,
                SADB_EALG_DES_CBC, SADB_AALG_MD5_HMAC },
            { ESP_DES, AUTH_ALGORITHM_HMAC_SHA1,
                DES_CBC_BLOCK_SIZE,
                HMAC_SHA1_KEY_LEN, SADB_EALG_DES_CBC, SADB_AALG_SHA1_HMAC },

            { ESP_3DES, AUTH_ALGORITHM_NONE,
                DES_CBC_BLOCK_SIZE * 3, 0,
                SADB_EALG_3DES_CBC, SADB_AALG_NONE },
            { ESP_3DES, AUTH_ALGORITHM_HMAC_MD5,
                DES_CBC_BLOCK_SIZE * 3, HMAC_MD5_KEY_LEN,
                SADB_EALG_3DES_CBC, SADB_AALG_MD5_HMAC },
            { ESP_3DES, AUTH_ALGORITHM_HMAC_SHA1,
                DES_CBC_BLOCK_SIZE * 3, HMAC_SHA1_KEY_LEN,
                SADB_EALG_3DES_CBC, SADB_AALG_SHA1_HMAC },
        };

#ifdef NAT_TRAVERSAL
        u_int8_t natt_type = 0;
        u_int16_t natt_sport = 0, natt_dport = 0;
        ip_address natt_oa;

        if (st->nat_traversal & NAT_T_DETECTED) {
            natt_type = (st->nat_traversal & NAT_T_WITH_PORT_FLOATING) ?
                ESPINUDP_WITH_NON_ESP : ESPINUDP_WITH_NON_IKE;
            natt_sport = inbound? c->spd.that.host_port : c->spd.this.host_port;
            natt_dport = inbound? c->spd.this.host_port : c->spd.that.host_port;
            natt_oa = st->nat_oa;
        }
#endif

        for (ei = esp_info; ; ei++)
        {
            if (ei == &esp_info[elemsof(esp_info)])
            {
                /* Check for additional kernel alg */
#ifndef NO_KERNEL_ALG
                if ((ei=kernel_alg_esp_info(st->st_esp.attrs.transid, 
                                        st->st_esp.attrs.auth))!=NULL) {
                        break;
                }
#endif

                /* note: enum_show may use a static buffer, so two
                 * calls in one printf would be a mistake.
                 * enum_name does the same job, without a static buffer,
                 * assuming the name will be found.
                 */
                loglog(RC_LOG_SERIOUS, "ESP transform %s / auth %s not implemented yet"
                    , enum_name(&esp_transformid_names, st->st_esp.attrs.transid)
                    , enum_name(&auth_alg_names, st->st_esp.attrs.auth));
                goto fail;
            }

            if (st->st_esp.attrs.transid == ei->transid
            && st->st_esp.attrs.auth == ei->auth)
                break;
        }

        key_len = st->st_esp.attrs.key_len/8;
        if (key_len) {
                /* XXX: must change to check valid _range_ key_len */
                if (key_len > ei->enckeylen) {
                        loglog(RC_LOG_SERIOUS, "ESP transform %s passed key_len=%d > %d",
                        enum_name(&esp_transformid_names, st->st_esp.attrs.transid),
                        (int)key_len, (int)ei->enckeylen);
                        goto fail;
                }
        } else {
                key_len = ei->enckeylen;
        }
        /* Grrrrr.... f*cking 7 bits jurassic algos  */

        /* 168 bits in kernel, need 192 bits for keymat_len */
        if (ei->transid == ESP_3DES && key_len == 21) 
                key_len = 24;

        /* 56 bits in kernel, need 64 bits for keymat_len */
        if (ei->transid == ESP_DES && key_len == 7) 
                key_len = 8;

        /* divide up keying material */
        /* passert(st->st_esp.keymat_len == ei->enckeylen + ei->authkeylen); */
        DBG(DBG_KLIPS|DBG_CONTROL|DBG_PARSING, 
                if(st->st_esp.keymat_len != key_len + ei->authkeylen)
                        DBG_log("keymat_len=%d key_len=%d authkeylen=%d",
                                st->st_esp.keymat_len, (int)key_len, (int)ei->authkeylen);
        );
        passert(st->st_esp.keymat_len == key_len + ei->authkeylen);

        set_text_said(text_said, &dst.addr, esp_spi, SA_ESP);

        said_next->src = &src.addr;
        said_next->dst = &dst.addr;
        said_next->src_client = &src_client;
        said_next->dst_client = &dst_client;
        said_next->spi = esp_spi;
        said_next->satype = SADB_SATYPE_ESP;
        said_next->replay_window = (kernel_ops->type == KERNEL_TYPE_KLIPS) ? REPLAY_WINDOW : REPLAY_WINDOW_XFRM;
        said_next->authalg = ei->authalg;
        said_next->authkeylen = ei->authkeylen;
        /* said_next->authkey = esp_dst_keymat + ei->enckeylen; */
        said_next->authkey = esp_dst_keymat + key_len;
        said_next->encalg = ei->encryptalg;
        /* said_next->enckeylen = ei->enckeylen; */
        said_next->enckeylen = key_len;
        said_next->enckey = esp_dst_keymat;
        said_next->encapsulation = encapsulation;
        said_next->reqid = c->spd.reqid + 1;
#ifdef NAT_TRAVERSAL
        said_next->natt_sport = natt_sport;
        said_next->natt_dport = natt_dport;
        said_next->transid = st->st_esp.attrs.transid;
        said_next->natt_type = natt_type;
        said_next->natt_oa = &natt_oa;
#endif  
        said_next->text_said = text_said;

        if (!kernel_ops->add_sa(said_next, replace))
            goto fail;

        said_next++;

        encapsulation = ENCAPSULATION_MODE_TRANSPORT;
    }

    /* set up AH SA, if any */

    if (st->st_ah.present)
    {
        ipsec_spi_t ah_spi = inbound? st->st_ah.our_spi : st->st_ah.attrs.spi;
        u_char *ah_dst_keymat = inbound? st->st_ah.our_keymat : st->st_ah.peer_keymat;

        unsigned char authalg;

        switch (st->st_ah.attrs.auth)
        {
        case AUTH_ALGORITHM_HMAC_MD5:
            authalg = SADB_AALG_MD5_HMAC;
            break;

        case AUTH_ALGORITHM_HMAC_SHA1:
            authalg = SADB_AALG_SHA1_HMAC;
            break;

        default:
            loglog(RC_LOG_SERIOUS, "%s not implemented yet"
                , enum_show(&auth_alg_names, st->st_ah.attrs.auth));
            goto fail;
        }

        set_text_said(text_said, &dst.addr, ah_spi, SA_AH);

        said_next->src = &src.addr;
        said_next->dst = &dst.addr;
        said_next->src_client = &src_client;
        said_next->dst_client = &dst_client;
        said_next->spi = ah_spi;
        said_next->satype = SADB_SATYPE_AH;
        said_next->replay_window = (kernel_ops->type == KERNEL_TYPE_KLIPS) ? REPLAY_WINDOW : REPLAY_WINDOW_XFRM;
        said_next->authalg = authalg;
        said_next->authkeylen = st->st_ah.keymat_len;
        said_next->authkey = ah_dst_keymat;
        said_next->encapsulation = encapsulation;
        said_next->reqid = c->spd.reqid;
        said_next->text_said = text_said;

        if (!kernel_ops->add_sa(said_next, replace))
            goto fail;

        said_next++;

        encapsulation = ENCAPSULATION_MODE_TRANSPORT;
    }

    if (st->st_ah.attrs.encapsulation == ENCAPSULATION_MODE_TUNNEL
    || st->st_esp.attrs.encapsulation == ENCAPSULATION_MODE_TUNNEL
    || st->st_ipcomp.attrs.encapsulation == ENCAPSULATION_MODE_TUNNEL)
    {
        encapsulation = ENCAPSULATION_MODE_TUNNEL;
    }

    if (kernel_ops->inbound_eroute ? c->spd.eroute_owner == SOS_NOBODY
        : encapsulation == ENCAPSULATION_MODE_TUNNEL)
    {
        /* If inbound, and policy does not specifie DISABLEARRIVALCHECK,
         * tell KLIPS to enforce the IP addresses appropriate for this tunnel.
         * Note reversed ends.
         * Not much to be done on failure.
         */
        if (inbound && (c->policy & POLICY_DISABLEARRIVALCHECK) == 0)
        {
            struct pfkey_proto_info proto_info[4];
            int i = 0;
            
            if (st->st_ipcomp.present)
            {
                proto_info[i].proto = IPPROTO_COMP;
                proto_info[i].encapsulation = st->st_ipcomp.attrs.encapsulation;
                proto_info[i].reqid = c->spd.reqid + 2;
                i++;
            }
            
            if (st->st_esp.present)
            {
                proto_info[i].proto = IPPROTO_ESP;
                proto_info[i].encapsulation = st->st_esp.attrs.encapsulation;
                proto_info[i].reqid = c->spd.reqid + 1;
                i++;
            }
            
            if (st->st_ah.present)
            {
                proto_info[i].proto = IPPROTO_AH;
                proto_info[i].encapsulation = st->st_ah.attrs.encapsulation;
                proto_info[i].reqid = c->spd.reqid;
                i++;
            }
            
            proto_info[i].proto = 0;
            
            if (kernel_ops->inbound_eroute
                && encapsulation == ENCAPSULATION_MODE_TUNNEL)
            {
                proto_info[0].encapsulation = ENCAPSULATION_MODE_TUNNEL;
                for (i = 1; proto_info[i].proto; i++)
                {
                    proto_info[i].encapsulation = ENCAPSULATION_MODE_TRANSPORT;
                }
            }
            
            /* MCR - should be passed a spd_eroute structure here */
            (void) raw_eroute(&c->spd.that.host_addr, &c->spd.that.client
                              , &c->spd.this.host_addr, &c->spd.this.client
                              , inner_spi, proto, satype, c->spd.this.protocol
                              , proto_info, 0
                              , ERO_ADD_INBOUND, "add inbound");
        }
    }

    /* If there are multiple SPIs, group them. */
    
    if (kernel_ops->grp_sa && said_next > &said[1])
    {
        struct kernel_sa *s;
        
        /* group SAs, two at a time, inner to outer (backwards in said[])
         * The grouping is by pairs.  So if said[] contains ah esp ipip,
         * the grouping would be ipip:esp, esp:ah.
         */
        for (s = said; s < said_next-1; s++)
        {
            char
                text_said0[SATOT_BUF],
                text_said1[SATOT_BUF];

            /* group s[1] and s[0], in that order */
            
            set_text_said(text_said0, s[0].dst, s[0].spi, s[0].proto);
            set_text_said(text_said1, s[1].dst, s[1].spi, s[1].proto);
            
            DBG(DBG_KLIPS, DBG_log("grouping %s and %s", text_said1, text_said0));
            
            s[0].text_said = text_said0;
            s[1].text_said = text_said1;
            
            if (!kernel_ops->grp_sa(s + 1, s))
                goto fail;
        }
        /* could update said, but it will not be used */
    }

    return TRUE;

fail:
    {
        /* undo the done SPIs */
        while (said_next-- != said)
            (void) del_spi(said_next->spi, said_next->proto
                , &src.addr, said_next->dst);
        return FALSE;
    }
}

/* teardown_ipsec_sa is a canibalized version of setup_ipsec_sa */

static bool
teardown_half_ipsec_sa(struct state *st, bool inbound)
{
    /* We need to delete AH, ESP, and IP in IP SPIs.
     * But if there is more than one, they have been grouped
     * so deleting any one will do.  So we just delete the
     * first one found.  It may or may not be the only one.
     */
    struct connection *c = st->st_connection;
    struct {
        unsigned proto;
        struct ipsec_proto_info *info;
    } protos[4];
    int i;
    bool result;

    i = 0;
    if (kernel_ops->inbound_eroute && inbound
        && c->spd.eroute_owner == SOS_NOBODY)
    {
        (void) raw_eroute(&c->spd.that.host_addr, &c->spd.that.client
            , &c->spd.this.host_addr, &c->spd.this.client
            , 256, IPSEC_PROTO_ANY, SADB_SATYPE_UNSPEC, c->spd.this.protocol
            , null_proto_info, 0
            , ERO_DEL_INBOUND, "delete inbound");
    }

    if (!kernel_ops->grp_sa)
    {
        if (st->st_ah.present)
        {
            protos[i].info = &st->st_ah;
            protos[i].proto = SA_AH;
            i++;
        }

        if (st->st_esp.present)
        {
            protos[i].info = &st->st_esp;
            protos[i].proto = SA_ESP;
            i++;
        }

        if (st->st_ipcomp.present)
        {
            protos[i].info = &st->st_ipcomp;
            protos[i].proto = SA_COMP;
            i++;
        }
    }
    else if (st->st_ah.present)
    {
        protos[i].info = &st->st_ah;
        protos[i].proto = SA_AH;
        i++;
    }
    else if (st->st_esp.present)
    {
        protos[i].info = &st->st_esp;
        protos[i].proto = SA_ESP;
        i++;
    }
    else
    {
        impossible();   /* neither AH nor ESP in outbound SA bundle! */
    }
    protos[i].proto = 0;

    result = TRUE;
    for (i = 0; protos[i].proto; i++)
    {
        unsigned proto = protos[i].proto;
        ipsec_spi_t spi;
        const ip_address *src, *dst;

        if (inbound)
        {
            spi = protos[i].info->our_spi;
            src = &c->spd.that.host_addr;
            dst = &c->spd.this.host_addr;
        }
        else
        {
            spi = protos[i].info->attrs.spi;
            src = &c->spd.this.host_addr;
            dst = &c->spd.that.host_addr;
        }

        result &= del_spi(spi, proto, src, dst);
    }
    return result;
}

/*
 * get information about a given sa
 */
bool
get_sa_info(struct state *st, bool inbound, u_int *bytes, time_t *use_time)
{
    char text_said[SATOT_BUF];
    struct kernel_sa sa;
    struct connection *c = st->st_connection;

    *use_time = UNDEFINED_TIME;

    if (kernel_ops->get_sa == NULL || !st->st_esp.present)
        return FALSE;

    memset(&sa, 0, sizeof(sa));
    sa.proto = SA_ESP;

    if (inbound)
    {
        sa.src = &c->spd.that.host_addr;
        sa.dst = &c->spd.this.host_addr;
        sa.spi = st->st_esp.our_spi;
    }
    else
    {
        sa.src = &c->spd.this.host_addr;
        sa.dst = &c->spd.that.host_addr;
        sa.spi = st->st_esp.attrs.spi;
    }
    set_text_said(text_said, sa.dst, sa.spi, sa.proto);

    sa.text_said = text_said;

    DBG(DBG_KLIPS,
        DBG_log("get %s", text_said)
    )
    if (!kernel_ops->get_sa(&sa, bytes))
        return FALSE;
    DBG(DBG_KLIPS,
        DBG_log("  current: %d bytes", *bytes)
    )

    if (st->st_serialno == c->spd.eroute_owner)
    {
        DBG(DBG_KLIPS,
            DBG_log("get %sbound policy with reqid %u"
                , inbound? "in":"out", (u_int)c->spd.reqid + 1)
        )
        sa.transport_proto = c->spd.this.protocol;
        sa.encapsulation = st->st_esp.attrs.encapsulation;

        if (inbound)
        {
            sa.src_client = &c->spd.that.client;
            sa.dst_client = &c->spd.this.client;
        }
        else
        {
            sa.src_client = &c->spd.this.client;
            sa.dst_client = &c->spd.that.client;
        }
        if (!kernel_ops->get_policy(&sa, inbound, use_time))
            return FALSE;
        DBG(DBG_KLIPS,
            DBG_log("  use_time: %s", timetoa(use_time, FALSE))
        )
    }
    return TRUE;
}

const struct kernel_ops *kernel_ops;

#endif /* KLIPS */

void
init_kernel(void)
{
#ifdef KLIPS

    if (no_klips)
    {
        kernel_ops = &noklips_kernel_ops;
        return;
    }

    init_pfkey();

    kernel_ops = &klips_kernel_ops;

#if defined(linux) && defined(KERNEL26_SUPPORT)
    {
        bool linux_ipsec = 0;
        struct stat buf;

        linux_ipsec = (stat("/proc/net/pfkey", &buf) == 0);
        if (linux_ipsec)
            {
                plog("Using Linux 2.6 IPsec interface code");
                kernel_ops = &linux_kernel_ops;
            }
        else
            {
                plog("Using KLIPS IPsec interface code");
            }
    }
#endif

    if (kernel_ops->init)
    {
        kernel_ops->init();
    }

    /* register SA types that we can negotiate */
    can_do_IPcomp = FALSE;  /* until we get a response from KLIPS */
    kernel_ops->pfkey_register();

    if (!kernel_ops->policy_lifetime)
    {
        event_schedule(EVENT_SHUNT_SCAN, SHUNT_SCAN_INTERVAL, NULL);
    }
#endif
}

/* Note: install_inbound_ipsec_sa is only used by the Responder.
 * The Responder will subsequently use install_ipsec_sa for the outbound.
 * The Initiator uses install_ipsec_sa to install both at once.
 */
bool
install_inbound_ipsec_sa(struct state *st)
{
    struct connection *const c = st->st_connection;

    /* If our peer has a fixed-address client, check if we already
     * have a route for that client that conflicts.  We will take this
     * as proof that that route and the connections using it are
     * obsolete and should be eliminated.  Interestingly, this is
     * the only case in which we can tell that a connection is obsolete.
     */
    passert(c->kind == CK_PERMANENT || c->kind == CK_INSTANCE);
    if (c->spd.that.has_client)
    {
        for (;;)
        {
            struct spd_route *esr;
            struct connection *o = route_owner(c, &esr, NULL, NULL);

            if (o == NULL)
                break;  /* nobody has a route */

            /* note: we ignore the client addresses at this end */
            if (sameaddr(&o->spd.that.host_addr, &c->spd.that.host_addr)
            && o->interface == c->interface)
                break;  /* existing route is compatible */

            if (o->kind == CK_TEMPLATE && streq(o->name, c->name))
                break;  /* ??? is this good enough?? */

            loglog(RC_LOG_SERIOUS, "route to peer's client conflicts with \"%s\" %s; releasing old connection to free the route"
                , o->name, ip_str(&o->spd.that.host_addr));
            release_connection(o, FALSE);
        }
    }

    DBG(DBG_CONTROL, DBG_log("install_inbound_ipsec_sa() checking if we can route"));
    /* check that we will be able to route and eroute */
    switch (could_route(c))
    {
    case route_easy:
    case route_nearconflict:
        break;

    default:
        return FALSE;
    }

#ifdef KLIPS
    /* (attempt to) actually set up the SAs */
    return setup_half_ipsec_sa(st, TRUE);
#else /* !KLIPS */
    DBG(DBG_CONTROL, DBG_log("install_inbound_ipsec_sa()"));
    return TRUE;
#endif /* !KLIPS */
}

/* Install a route and then a prospective shunt eroute or an SA group eroute.
 * Assumption: could_route gave a go-ahead.
 * Any SA Group must have already been created.
 * On failure, steps will be unwound.
 */
bool
route_and_eroute(struct connection *c USED_BY_KLIPS
                 , struct spd_route *sr USED_BY_KLIPS
                 , struct state *st USED_BY_KLIPS)
{
#ifdef KLIPS
    struct spd_route *esr;
    struct spd_route *rosr;
    struct connection *ero      /* who, if anyone, owns our eroute? */
        , *ro = route_owner(c, &rosr, &ero, &esr);
    bool eroute_installed = FALSE
        , firewall_notified = FALSE
        , route_installed = FALSE;

    struct connection *ero_top;
    struct bare_shunt **bspp;

    DBG(DBG_CONTROLMORE,
        DBG_log("route_and_eroute with c: %s (next: %s) ero:%s esr:{%p} ro:%s rosr:{%p} and state: %lu"
                , c->name
                , (c->policy_next ? c->policy_next->name : "none")
                , ero ? ero->name : "null"
                , esr 
                , ro ? ro->name : "null"
                , rosr
                , st ? st->st_serialno : 0));

    /* look along the chain of policies for one with the same name */
    ero_top = ero;

#if 0
    /* XXX - mcr this made sense before, and likely will make sense
     * again, so I'l leaving this to remind me what is up */
    if (ero!= NULL && ero->routing == RT_UNROUTED_KEYED)
        ero = NULL;

    for (ero2 = ero; ero2 != NULL; ero2 = ero->policy_next)
        if ((ero2->kind == CK_TEMPLATE || ero2->kind==CK_SECONDARY)
        && streq(ero2->name, c->name))
            break;
#endif

    bspp = (ero == NULL)
        ? bare_shunt_ptr(&sr->this.client, &sr->that.client, sr->this.protocol)
        : NULL;

    /* install the eroute */

    passert(bspp == NULL || ero == NULL);       /* only one non-NULL */

    if (bspp != NULL || ero != NULL)
    {
        /* We're replacing an eroute */

        /* if no state provided, then install a shunt for later */
        if (st == NULL)
            eroute_installed = shunt_eroute(c, sr, RT_ROUTED_PROSPECTIVE
                                            , ERO_REPLACE, "replace");
        else
            eroute_installed = sag_eroute(st, sr, ERO_REPLACE, "replace");

#if 0
        /* XXX - MCR. I previously felt that this was a bogus check */
        if (ero != NULL && ero != c && esr != sr)
        {
            /* By elimination, we must be eclipsing ero.  Check. */
            passert(ero->kind == CK_TEMPLATE && streq(ero->name, c->name));
            passert(LHAS(LELEM(RT_ROUTED_PROSPECTIVE) | LELEM(RT_ROUTED_ECLIPSED)
                , esr->routing));
            passert(samesubnet(&esr->this.client, &sr->this.client)
                && samesubnet(&esr->that.client, &sr->that.client));
        }
#endif
        /* remember to free bspp iff we make it out of here alive */
    }
    else
    {
        /* we're adding an eroute */

        /* if no state provided, then install a shunt for later */
        if (st == NULL)
            eroute_installed = shunt_eroute(c, sr, RT_ROUTED_PROSPECTIVE
                                            , ERO_ADD, "add");
        else
            eroute_installed = sag_eroute(st, sr, ERO_ADD, "add");
    }

    /* notify the firewall of a new tunnel */

    if (eroute_installed)
    {
        /* do we have to notify the firewall?  Yes, if we are installing
         * a tunnel eroute and the firewall wasn't notified
         * for a previous tunnel with the same clients.  Any Previous
         * tunnel would have to be for our connection, so the actual
         * test is simple.
         */
        firewall_notified = st == NULL  /* not a tunnel eroute */
            || sr->eroute_owner != SOS_NOBODY   /* already notified */
            || do_command(c, sr, "up"); /* go ahead and notify */
    }

    /* install the route */

    DBG(DBG_CONTROL,
        DBG_log("route_and_eroute: firewall_notified: %s"
                , firewall_notified ? "true" : "false"));
    if (!firewall_notified)
    {
        /* we're in trouble -- don't do routing */
    }
    else if (ro == NULL)
    {
        /* a new route: no deletion required, but preparation is */
        (void) do_command(c, sr, "prepare");    /* just in case; ignore failure */
        route_installed = do_command(c, sr, "route");
    }
    else if (routed(sr->routing)
    || routes_agree(ro, c))
    {
        route_installed = TRUE; /* nothing to be done */
    }
    else
    {
        /* Some other connection must own the route
         * and the route must disagree.  But since could_route
         * must have allowed our stealing it, we'll do so.
         *
         * A feature of LINUX allows us to install the new route
         * before deleting the old if the nexthops differ.
         * This reduces the "window of vulnerability" when packets
         * might flow in the clear.
         */
        if (sameaddr(&sr->this.host_nexthop, &esr->this.host_nexthop))
        {
            (void) do_command(ro, sr, "unroute");
            route_installed = do_command(c, sr, "route");
        }
        else
        {
            route_installed = do_command(c, sr, "route");
            (void) do_command(ro, sr, "unroute");
        }

        /* record unrouting */
        if (route_installed)
        {
            do {
                passert(!erouted(rosr->routing));
                rosr->routing = RT_UNROUTED;

                /* no need to keep old value */
                ro = route_owner(c, &rosr, NULL, NULL);
            } while (ro != NULL);
        }
    }

    /* all done -- clean up */
    if (route_installed)
    {
        /* Success! */

        if (bspp != NULL)
        {
            free_bare_shunt(bspp);
        }
        else if (ero != NULL && ero != c)
        {
            /* check if ero is an ancestor of c. */
            struct connection *ero2;

            for (ero2 = c; ero2 != NULL && ero2 != c; ero2 = ero2->policy_next)
                ;

            if (ero2 == NULL)
            {
                /* By elimination, we must be eclipsing ero.  Checked above. */
                if (ero->spd.routing != RT_ROUTED_ECLIPSED)
                {
                    ero->spd.routing = RT_ROUTED_ECLIPSED;
                    eclipse_count++;
                }
            }
        }

        if (st == NULL)
        {
            passert(sr->eroute_owner == SOS_NOBODY);
            sr->routing = RT_ROUTED_PROSPECTIVE;
        }
        else
        {
            char cib[CONN_INST_BUF];
            sr->routing = RT_ROUTED_TUNNEL;

            DBG(DBG_CONTROL,
                DBG_log("route_and_eroute: instance \"%s\"%s, setting eroute_owner {spd=%p,sr=%p} to #%ld (was #%ld) (newest_ipsec_sa=#%ld)"
                        , st->st_connection->name
                        , (fmt_conn_instance(st->st_connection, cib), cib)
                        , &st->st_connection->spd, sr
                        , st->st_serialno
                        , sr->eroute_owner
                        , st->st_connection->newest_ipsec_sa));
            sr->eroute_owner = st->st_serialno;
        }

        return TRUE;
    }
    else
    {
        /* Failure!  Unwind our work. */
        if (firewall_notified && sr->eroute_owner == SOS_NOBODY)
            (void) do_command(c, sr, "down");

        if (eroute_installed)
        {
            /* Restore original eroute, if we can.
             * Since there is nothing much to be done if the restoration
             * fails, ignore success or failure.
             */
            if (bspp != NULL)
            {
                /* Restore old bare_shunt.
                 * I don't think that this case is very likely.
                 * Normally a bare shunt would have been assigned
                 * to a connection before we've gotten this far.
                 */
                struct bare_shunt *bs = *bspp;

                (void) raw_eroute(&bs->said.dst /* should be useless */
                    , &bs->ours
                    , &bs->said.dst     /* should be useless */
                    , &bs->his
                    , bs->said.spi      /* network order */
                    , SA_INT
                    , SADB_X_SATYPE_INT
                    , 0
                    , null_proto_info
                    , SHUNT_PATIENCE
                    , ERO_REPLACE, "restore");
            }
            else if (ero != NULL)
            {
                /* restore ero's former glory */
                if (esr->eroute_owner == SOS_NOBODY)
                {
                    /* note: normal or eclipse case */
                    (void) shunt_eroute(ero, esr
                                        , esr->routing, ERO_REPLACE, "restore");
                }
                else
                {
                    /* Try to find state that owned eroute.
                     * Don't do anything if it cannot be found.
                     * This case isn't likely since we don't run
                     * the updown script when replacing a SA group
                     * with its successor (for the same conn).
                     */
                    struct state *ost = state_with_serialno(esr->eroute_owner);

                    if (ost != NULL)
                        (void) sag_eroute(ost, esr, ERO_REPLACE, "restore");
                }
            }
            else
            {
                /* there was no previous eroute: delete whatever we installed */
                if (st == NULL)
                    (void) shunt_eroute(c, sr
                                        , sr->routing, ERO_DELETE, "delete");
                else
                    (void) sag_eroute(st, sr
                                      , ERO_DELETE, "delete");
            }
        }

        return FALSE;
    }
#else /* !KLIPS */
    return TRUE;
#endif /* !KLIPS */
}

bool
install_ipsec_sa(struct state *st, bool inbound_also USED_BY_KLIPS)
{
#ifdef KLIPS
    struct spd_route *sr;

    DBG(DBG_CONTROL, DBG_log("install_ipsec_sa() for #%ld: %s"
                             , st->st_serialno
                             , inbound_also?
                             "inbound and outbound" : "outbound only"));

    switch (could_route(st->st_connection))
    {
    case route_easy:
    case route_nearconflict:
        break;

    default:
        return FALSE;
    }

    /* (attempt to) actually set up the SA group */
    if ((inbound_also && !setup_half_ipsec_sa(st, TRUE))
    || !setup_half_ipsec_sa(st, FALSE))
        return FALSE;

    for (sr = &st->st_connection->spd; sr != NULL; sr = sr->next)
    {
        DBG(DBG_CONTROL, DBG_log("sr for #%ld: %s"
                                 , st->st_serialno
                                 , enum_name(&routing_story, sr->routing)));

        /*
         * if the eroute owner is not us, then make it us.
         * See test co-terminal-02, pluto-rekey-01, pluto-unit-02/oppo-twice
         */
        pexpect(sr->eroute_owner == SOS_NOBODY
                || sr->routing >= RT_ROUTED_TUNNEL);

        if (sr->eroute_owner != st->st_serialno
            && sr->routing != RT_UNROUTED_KEYED)
        {
            if (!route_and_eroute(st->st_connection, sr, st))
            {
                delete_ipsec_sa(st, FALSE);
                /* XXX go and unroute any SRs that were successfully
                 * routed already.
                 */
                return FALSE;
            }
        }
    }
#else /* !KLIPS */
    DBG(DBG_CONTROL, DBG_log("install_ipsec_sa() %s"
        , inbound_also? "inbound and oubound" : "outbound only"));

    switch (could_route(st->st_connection))
    {
    case route_easy:
    case route_nearconflict:
        break;

    default:
        return FALSE;
    }


#endif /* !KLIPS */

    return TRUE;
}

/* delete an IPSEC SA.
 * we may not succeed, but we bull ahead anyway because
 * we cannot do anything better by recognizing failure
 */
void
delete_ipsec_sa(struct state *st USED_BY_KLIPS, bool inbound_only USED_BY_KLIPS)
{
#ifdef KLIPS
    if (!inbound_only)
    {
        /* If the state is the eroute owner, we must adjust
         * the routing for the connection.
         */
        struct connection *c = st->st_connection;
        struct spd_route *sr;

        passert(st->st_connection);

        for (sr = &c->spd; sr; sr = sr->next)
        {
            if (sr->eroute_owner == st->st_serialno
            && sr->routing == RT_ROUTED_TUNNEL)
            {
                sr->eroute_owner = SOS_NOBODY;

                /* Routing should become RT_ROUTED_FAILURE,
                 * but if POLICY_FAIL_NONE, then we just go
                 * right back to RT_ROUTED_PROSPECTIVE as if no
                 * failure happened.
                 */
                sr->routing = (c->policy & POLICY_FAIL_MASK) == POLICY_FAIL_NONE
                    ? RT_ROUTED_PROSPECTIVE : RT_ROUTED_FAILURE;

                (void) do_command(c, sr, "down");
                if ((c->policy & POLICY_DONT_REKEY)
                && c->kind == CK_INSTANCE)
                {
                    /* in this special case, even if the connection
                     * is still alive (due to an ISAKMP SA),
                     * we get rid of routing.
                     * Even though there is still an eroute, the c->routing
                     * setting will convince unroute_connection to delete it.
                     * unroute_connection would be upset if c->routing == RT_ROUTED_TUNNEL
                     */
                    unroute_connection(c);
                }
                else
                {
                    (void) shunt_eroute(c, sr, sr->routing, ERO_REPLACE, "replace with shunt");
                }
            }
        }
        (void) teardown_half_ipsec_sa(st, FALSE);
    }
    (void) teardown_half_ipsec_sa(st, TRUE);
#else /* !KLIPS */
    DBG(DBG_CONTROL, DBG_log("if I knew how, I'd eroute() and teardown_ipsec_sa()"));
#endif /* !KLIPS */
}
#ifdef NAT_TRAVERSAL
#ifdef KLIPS
static bool update_nat_t_ipsec_esp_sa (struct state *st, bool inbound)
{
        struct connection *c = st->st_connection;
        char text_said[SATOT_BUF];
        struct kernel_sa sa;    
        ip_address
                src = inbound? c->spd.that.host_addr : c->spd.this.host_addr,
                dst = inbound? c->spd.this.host_addr : c->spd.that.host_addr;
                

        ipsec_spi_t esp_spi = inbound? st->st_esp.our_spi : st->st_esp.attrs.spi;

        u_int16_t
                natt_sport = inbound? c->spd.that.host_port : c->spd.this.host_port,
                natt_dport = inbound? c->spd.this.host_port : c->spd.that.host_port;

        set_text_said(text_said, &dst, esp_spi, SA_ESP);
                
        memset(&sa, 0, sizeof(sa));
        sa.spi = esp_spi;
        sa.src = &src;
        sa.dst = &dst;
        sa.text_said = text_said;
        sa.authalg = alg_info_esp_aa2sadb(st->st_esp.attrs.auth);
        sa.natt_sport = natt_sport;
        sa.natt_dport = natt_dport;
        sa.transid = st->st_esp.attrs.transid;
        
        return kernel_ops->add_sa(&sa, TRUE);

}
#endif

bool update_ipsec_sa (struct state *st USED_BY_KLIPS)
{
#ifdef KLIPS
        if (IS_IPSEC_SA_ESTABLISHED(st->st_state)) {
                if ((st->st_esp.present) && (
                        (!update_nat_t_ipsec_esp_sa (st, TRUE)) ||
                        (!update_nat_t_ipsec_esp_sa (st, FALSE)))) {
                        return FALSE;
                }
        }
        else if (IS_ONLY_INBOUND_IPSEC_SA_ESTABLISHED(st->st_state)) {
                if ((st->st_esp.present) && (!update_nat_t_ipsec_esp_sa (st, FALSE))) {
                        return FALSE;
                }
        }
        else {
                DBG_log("assert failed at %s:%d st_state=%d", __FILE__, __LINE__,
                        st->st_state);
                return FALSE;
        }
        return TRUE;
#else /* !KLIPS */
    DBG(DBG_CONTROL, DBG_log("if I knew how, I'd update_ipsec_sa()"));
    return TRUE;
#endif /* !KLIPS */
}
#endif

/* Check if there was traffic on given SA during the last idle_max
 * seconds. If TRUE, the SA was idle and DPD exchange should be performed.
 * If FALSE, DPD is not necessary. We also return TRUE for errors, as they
 * could mean that the SA is broken and needs to be replace anyway.
 */
bool
was_eroute_idle(struct state *st, time_t idle_max, time_t *idle_time)
{
    static const char procname[] = "/proc/net/ipsec_spi";
    FILE *f;
    char buf[1024];
    u_int bytes;
    int ret = TRUE;

    passert(st != NULL);

    f = fopen(procname, "r");
    if (f == NULL)
    {
        /* Can't open the file, perhaps were are on 26sec? */
        time_t use_time;

        if (get_sa_info(st, TRUE, &bytes, &use_time)
        && use_time != UNDEFINED_TIME)
        {
            *idle_time = time(NULL) - use_time;
            ret = *idle_time >= idle_max;
        }
    }
    else 
    {
        while (f != NULL)
        {
            char *line;
            char text_said[SATOT_BUF];
            u_int8_t proto = 0;
            ip_address dst;
            ip_said said;
            ipsec_spi_t spi = 0;
            static const char idle[] = "idle=";

            dst = st->st_connection->spd.this.host_addr; /* inbound SA */
            if (st->st_ah.present)
            {
                proto = SA_AH;
                spi = st->st_ah.our_spi;
            }
            if (st->st_esp.present)
            {
                proto = SA_ESP;
                spi = st->st_esp.our_spi;
            }

            if (proto == 0 && spi == 0)
            {
                ret = TRUE;
                break;
            }

            initsaid(&dst, spi, proto, &said);
            satot(&said, 'x', text_said, SATOT_BUF);

            line = fgets(buf, sizeof(buf), f);
            if (line == NULL)
            {
                /* Reached end of list */
                ret = TRUE;
                break;
            }

            if (strncmp(line, text_said, strlen(text_said)) == 0)
            {
                /* we found a match, now try to find idle= */
                char *p = strstr(line, idle);

                if (p == NULL)
                {
                    /* SAs which haven't been used yet don't have it */
                    ret = TRUE; /* it didn't have traffic */
                    break;
                }
                p += sizeof(idle)-1;
                if (*p == '\0')
                {
                    ret = TRUE; /* be paranoid */
                    break;
                }
                if (sscanf(p, "%d", (int *) idle_time) <= 0)
                {
                    ret = TRUE;
                    break;
                }
                if (*idle_time >= idle_max)
                {
                    ret = TRUE;
                    break;
                }
                else
                {
                    ret = FALSE;
                    break;
                }
            }
        }
        fclose(f);
    }
    return ret;
}