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

/* routines for state objects
 * Copyright (C) 1997 Angelos D. Keromytis.
 * Copyright (C) 1998-2001  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: state.c,v 1.13 2006/04/29 18:16:02 as Exp $
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <sys/queue.h>

#include <freeswan.h>

#include "constants.h"
#include "defs.h"
#include "connections.h"
#include "state.h"
#include "kernel.h"
#include "log.h"
#include "packet.h"     /* so we can calculate sizeof(struct isakmp_hdr) */
#include "keys.h"       /* for free_public_key */
#include "rnd.h"
#include "timer.h"
#include "whack.h"
#include "demux.h"      /* needs packet.h */
#include "ipsec_doi.h"  /* needs demux.h and state.h */

#include "sha1.h"
#include "md5.h"
#include "crypto.h" /* requires sha1.h and md5.h */

/*
 * Global variables: had to go somewhere, might as well be this file.
 */

u_int16_t pluto_port = IKE_UDP_PORT;    /* Pluto's port */

/*
 * This file has the functions that handle the
 * state hash table and the Message ID list.
 */

/* Message-IDs
 *
 * A Message ID is contained in each IKE message header.
 * For Phase 1 exchanges (Main and Aggressive), it will be zero.
 * For other exchanges, which must be under the protection of an
 * ISAKMP SA, the Message ID must be unique within that ISAKMP SA.
 * Effectively, this labels the message as belonging to a particular
 * exchange.
 * BTW, we feel this uniqueness allows rekeying to be somewhat simpler
 * than specified by draft-jenkins-ipsec-rekeying-06.txt.
 *
 * A MessageID is a 32 bit unsigned number.  We represent the value
 * internally in network order -- they are just blobs to us.
 * They are unsigned numbers to make hashing and comparing easy.
 *
 * The following mechanism is used to allocate message IDs.  This
 * requires that we keep track of which numbers have already been used
 * so that we don't allocate one in use.
 */

struct msgid_list
{
    msgid_t               msgid; /* network order */
    struct msgid_list     *next;
};

bool
reserve_msgid(struct state *isakmp_sa, msgid_t msgid)
{
    struct msgid_list *p;

    passert(msgid != MAINMODE_MSGID);
    passert(IS_ISAKMP_ENCRYPTED(isakmp_sa->st_state));

    for (p = isakmp_sa->st_used_msgids; p != NULL; p = p->next)
        if (p->msgid == msgid)
            return FALSE;

    p = alloc_thing(struct msgid_list, "msgid");
    p->msgid = msgid;
    p->next = isakmp_sa->st_used_msgids;
    isakmp_sa->st_used_msgids = p;
    return TRUE;
}

msgid_t
generate_msgid(struct state *isakmp_sa)
{
    int timeout = 100;  /* only try so hard for unique msgid */
    msgid_t msgid;

    passert(IS_ISAKMP_ENCRYPTED(isakmp_sa->st_state));

    for (;;)
    {
        get_rnd_bytes((void *) &msgid, sizeof(msgid));
        if (msgid != 0 && reserve_msgid(isakmp_sa, msgid))
            break;

        if (--timeout == 0)
        {
            plog("gave up looking for unique msgid; using 0x%08lx"
                , (unsigned long) msgid);
            break;
        }
    }
    return msgid;
}


/* state table functions */

#define STATE_TABLE_SIZE 32

static struct state *statetable[STATE_TABLE_SIZE];

static struct state **
state_hash(const u_char *icookie, const u_char *rcookie, const ip_address *peer)
{
    u_int i = 0, j;
    const unsigned char *byte_ptr;
    size_t length = addrbytesptr(peer, &byte_ptr);

    DBG(DBG_RAW | DBG_CONTROL,
        DBG_dump("ICOOKIE:", icookie, COOKIE_SIZE);
        DBG_dump("RCOOKIE:", rcookie, COOKIE_SIZE);
        DBG_dump("peer:", byte_ptr, length));

    /* XXX the following hash is pretty pathetic */

    for (j = 0; j < COOKIE_SIZE; j++)
        i = i * 407 + icookie[j] + rcookie[j];

    for (j = 0; j < length; j++)
        i = i * 613 + byte_ptr[j];

    i = i % STATE_TABLE_SIZE;

    DBG(DBG_CONTROL, DBG_log("state hash entry %d", i));

    return &statetable[i];
}

/* Get a state object.
 * Caller must schedule an event for this object so that it doesn't leak.
 * Caller must insert_state().
 */
struct state *
new_state(void)
{
    static const struct state blank_state;      /* initialized all to zero & NULL */
    static so_serial_t next_so = SOS_FIRST;
    struct state *st;

    st = clone_thing(blank_state, "struct state in new_state()");
    st->st_serialno = next_so++;
    passert(next_so > SOS_FIRST);       /* overflow can't happen! */
    st->st_whack_sock = NULL_FD;
    DBG(DBG_CONTROL, DBG_log("creating state object #%lu at %p",
        st->st_serialno, (void *) st));
    return st;
}

/*
 * Initialize the state table (and mask*).
 */
void
init_states(void)
{
    int i;

    for (i = 0; i < STATE_TABLE_SIZE; i++)
        statetable[i] = (struct state *) NULL;
}

/* Find the state object with this serial number.
 * This allows state object references that don't turn into dangerous
 * dangling pointers: reference a state by its serial number.
 * Returns NULL if there is no such state.
 * If this turns out to be a significant CPU hog, it could be
 * improved to use a hash table rather than sequential seartch.
 */
struct state *
state_with_serialno(so_serial_t sn)
{
    if (sn >= SOS_FIRST)
    {
        struct state *st;
        int i;

        for (i = 0; i < STATE_TABLE_SIZE; i++)
            for (st = statetable[i]; st != NULL; st = st->st_hashchain_next)
                if (st->st_serialno == sn)
                    return st;
    }
    return NULL;
}

/* Insert a state object in the hash table. The object is inserted
 * at the begining of list.
 * Needs cookies, connection, and msgid.
 */
void
insert_state(struct state *st)
{
    struct state **p = state_hash(st->st_icookie, st->st_rcookie
        , &st->st_connection->spd.that.host_addr);

    passert(st->st_hashchain_prev == NULL && st->st_hashchain_next == NULL);

    if (*p != NULL)
    {
        passert((*p)->st_hashchain_prev == NULL);
        (*p)->st_hashchain_prev = st;
    }
    st->st_hashchain_next = *p;
    *p = st;

    /* Ensure that somebody is in charge of killing this state:
     * if no event is scheduled for it, schedule one to discard the state.
     * If nothing goes wrong, this event will be replaced by
     * a more appropriate one.
     */
    if (st->st_event == NULL)
        event_schedule(EVENT_SO_DISCARD, 0, st);
}

/* unlink a state object from the hash table, but don't free it
 */
void
unhash_state(struct state *st)
{
    /* unlink from forward chain */
    struct state **p = st->st_hashchain_prev == NULL
        ? state_hash(st->st_icookie, st->st_rcookie
                     , &st->st_connection->spd.that.host_addr)
        : &st->st_hashchain_prev->st_hashchain_next;

    /* unlink from forward chain */
    passert(*p == st);
    *p = st->st_hashchain_next;

    /* unlink from backward chain */
    if (st->st_hashchain_next != NULL)
    {
        passert(st->st_hashchain_next->st_hashchain_prev == st);
        st->st_hashchain_next->st_hashchain_prev = st->st_hashchain_prev;
    }

    st->st_hashchain_next = st->st_hashchain_prev = NULL;
}

/* Free the Whack socket file descriptor.
 * This has the side effect of telling Whack that we're done.
 */
void
release_whack(struct state *st)
{
    close_any(st->st_whack_sock);
}

/* delete a state object */
void
delete_state(struct state *st)
{
    struct connection *const c = st->st_connection;
    struct state *old_cur_state = cur_state == st? NULL : cur_state;

    set_cur_state(st);

    /* If DPD is enabled on this state object, clear any pending events */
    if(st->st_dpd_event != NULL)
            delete_dpd_event(st);

    /* if there is a suspended state transition, disconnect us */
    if (st->st_suspended_md != NULL)
    {
        passert(st->st_suspended_md->st == st);
        st->st_suspended_md->st = NULL;
    }

    /* tell the other side of any IPSEC SAs that are going down */
    if (IS_IPSEC_SA_ESTABLISHED(st->st_state)
    || IS_ISAKMP_SA_ESTABLISHED(st->st_state))
        send_delete(st);

    delete_event(st);   /* delete any pending timer event */

    /* Ditch anything pending on ISAKMP SA being established.
     * Note: this must be done before the unhash_state to prevent
     * flush_pending_by_state inadvertently and prematurely
     * deleting our connection.
     */
    flush_pending_by_state(st);

    /* effectively, this deletes any ISAKMP SA that this state represents */
    unhash_state(st);

    /* tell kernel to delete any IPSEC SA
     * ??? we ought to tell peer to delete IPSEC SAs
     */
    if (IS_IPSEC_SA_ESTABLISHED(st->st_state))
        delete_ipsec_sa(st, FALSE);
    else if (IS_ONLY_INBOUND_IPSEC_SA_ESTABLISHED(st->st_state))
        delete_ipsec_sa(st, TRUE);

    if (c->newest_ipsec_sa == st->st_serialno)
        c->newest_ipsec_sa = SOS_NOBODY;

    if (c->newest_isakmp_sa == st->st_serialno)
        c->newest_isakmp_sa = SOS_NOBODY;

    st->st_connection = NULL;   /* we might be about to free it */
    cur_state = old_cur_state;  /* without st_connection, st isn't complete */
    connection_discard(c);

    release_whack(st);

    /* from here on we are just freeing RAM */

    {
        struct msgid_list *p = st->st_used_msgids;

        while (p != NULL)
        {
            struct msgid_list *q = p;
            p = p->next;
            pfree(q);
        }
    }

    unreference_key(&st->st_peer_pubkey);

    if (st->st_sec_in_use)
        mpz_clear(&(st->st_sec));

    pfreeany(st->st_tpacket.ptr);
    pfreeany(st->st_rpacket.ptr);
    pfreeany(st->st_p1isa.ptr);
    pfreeany(st->st_gi.ptr);
    pfreeany(st->st_gr.ptr);
    pfreeany(st->st_shared.ptr);
    pfreeany(st->st_ni.ptr);
    pfreeany(st->st_nr.ptr);
    pfreeany(st->st_skeyid.ptr);
    pfreeany(st->st_skeyid_d.ptr);
    pfreeany(st->st_skeyid_a.ptr);
    pfreeany(st->st_skeyid_e.ptr);
    pfreeany(st->st_enc_key.ptr);
    pfreeany(st->st_ah.our_keymat);
    pfreeany(st->st_ah.peer_keymat);
    pfreeany(st->st_esp.our_keymat);
    pfreeany(st->st_esp.peer_keymat);

    pfree(st);
}

/*
 * Is a connection in use by some state?
 */
bool
states_use_connection(struct connection *c)
{
    /* are there any states still using it? */
    struct state *st = NULL;
    int i;

    for (i = 0; st == NULL && i < STATE_TABLE_SIZE; i++)
        for (st = statetable[i]; st != NULL; st = st->st_hashchain_next)
            if (st->st_connection == c)
                return TRUE;

    return FALSE;
}

/*
 * delete all states that were created for a given connection.
 * if relations == TRUE, then also delete states that share
 * the same phase 1 SA.
 */
void
delete_states_by_connection(struct connection *c, bool relations)
{
    int pass;
    /* this kludge avoids an n^2 algorithm */
    enum connection_kind ck = c->kind;
    struct spd_route *sr;

    /* save this connection's isakmp SA, since it will get set to later SOS_NOBODY */
    so_serial_t parent_sa = c->newest_isakmp_sa;

    if (ck == CK_INSTANCE)
        c->kind = CK_GOING_AWAY;

    /* We take two passes so that we delete any ISAKMP SAs last.
     * This allows Delete Notifications to be sent.
     * ?? We could probably double the performance by caching any
     * ISAKMP SA states found in the first pass, avoiding a second.
     */
    for (pass = 0; pass != 2; pass++)
    {
        int i;

        /* For each hash chain... */
        for (i = 0; i < STATE_TABLE_SIZE; i++)
        {
            struct state *st;

            /* For each state in the hash chain... */
            for (st = statetable[i]; st != NULL; )
            {
                struct state *this = st;

                st = st->st_hashchain_next;     /* before this is deleted */


                if ((this->st_connection == c
                        || (relations && parent_sa != SOS_NOBODY
                        && this->st_clonedfrom == parent_sa))
                        && (pass == 1 || !IS_ISAKMP_SA_ESTABLISHED(this->st_state)))
                {
                    struct state *old_cur_state
                        = cur_state == this? NULL : cur_state;
#ifdef DEBUG
                    lset_t old_cur_debugging = cur_debugging;
#endif

                    set_cur_state(this);
                    plog("deleting state (%s)"
                        , enum_show(&state_names, this->st_state));
                    delete_state(this);
                    cur_state = old_cur_state;
#ifdef DEBUG
                    cur_debugging = old_cur_debugging;
#endif
                }
            }
        }
    }
    
    sr = &c->spd;
    while (sr != NULL)
    {
        passert(sr->eroute_owner == SOS_NOBODY);
        passert(sr->routing != RT_ROUTED_TUNNEL);
        sr = sr->next;
    }

    if (ck == CK_INSTANCE)
    {
        c->kind = ck;
        delete_connection(c, relations);
    }
}

/* Walk through the state table, and delete each state whose phase 1 (IKE)
 * peer is among those given.
 */
void
delete_states_by_peer(ip_address *peer)
{
    char peerstr[ADDRTOT_BUF];
    int i;

    addrtot(peer, 0, peerstr, sizeof(peerstr));

    /* For each hash chain... */
    for (i = 0; i < STATE_TABLE_SIZE; i++)
    {
        struct state *st;

        /* For each state in the hash chain... */
        for (st = statetable[i]; st != NULL; )
        {
            struct state *this = st;
            struct spd_route *sr;
            struct connection *c = this->st_connection;

            st = st->st_hashchain_next; /* before this is deleted */

            /* ??? Is it not the case that the peer is the same for all spds? */
            for (sr = &c->spd; sr != NULL; sr = sr->next)
            {
                if (sameaddr(&sr->that.host_addr, peer))
                {
                    plog("peer %s for connection %s deleting - claimed to have crashed"
                         , peerstr
                         , c->name);
                    delete_states_by_connection(c, TRUE);
                    break;      /* can only delete it once */
                }
            }
        }
    }
}

/* Duplicate a Phase 1 state object, to create a Phase 2 object.
 * Caller must schedule an event for this object so that it doesn't leak.
 * Caller must insert_state().
 */
struct state *
duplicate_state(struct state *st)
{
    struct state *nst;

    DBG(DBG_CONTROL, DBG_log("duplicating state object #%lu",
        st->st_serialno));

    /* record use of the Phase 1 state */
    st->st_outbound_count++;
    st->st_outbound_time = now();

    nst = new_state();

    memcpy(nst->st_icookie, st->st_icookie, COOKIE_SIZE);
    memcpy(nst->st_rcookie, st->st_rcookie, COOKIE_SIZE);
    
    nst->st_connection = st->st_connection;
    nst->st_doi = st->st_doi;
    nst->st_situation = st->st_situation;
    nst->st_clonedfrom = st->st_serialno;
    nst->st_oakley = st->st_oakley;
    nst->st_modecfg = st->st_modecfg;

#   define clone_chunk(ch, name) \
        clonetochunk(nst->ch, st->ch.ptr, st->ch.len, name)

    clone_chunk(st_skeyid_d, "st_skeyid_d in duplicate_state");
    clone_chunk(st_skeyid_a, "st_skeyid_a in duplicate_state");
    clone_chunk(st_skeyid_e, "st_skeyid_e in duplicate_state");
    clone_chunk(st_enc_key, "st_enc_key in duplicate_state");

#   undef clone_chunk

    return nst;
}

#if 1
void for_each_state(void *(f)(struct state *, void *data), void *data)
{
        struct state *st, *ocs = cur_state;
        int i;
        for (i=0; i<STATE_TABLE_SIZE; i++) {
                for (st = statetable[i]; st != NULL; st = st->st_hashchain_next) {
                        set_cur_state(st);
                        f(st, data);
                }
        }
        cur_state = ocs;
}
#endif

/*
 * Find a state object.
 */
struct state *
find_state(const u_char *icookie
, const u_char *rcookie
, const ip_address *peer
, msgid_t /*network order*/ msgid)
{
    struct state *st = *state_hash(icookie, rcookie, peer);

    while (st != (struct state *) NULL)
        if (sameaddr(peer, &st->st_connection->spd.that.host_addr)
        && memcmp(icookie, st->st_icookie, COOKIE_SIZE) == 0
        && memcmp(rcookie, st->st_rcookie, COOKIE_SIZE) == 0
        && msgid == st->st_msgid)
            break;
        else
            st = st->st_hashchain_next;

    DBG(DBG_CONTROL,
        if (st == NULL)
            DBG_log("state object not found");
        else
            DBG_log("state object #%lu found, in %s"
                , st->st_serialno
                , enum_show(&state_names, st->st_state)));

    return st;
}

/* Find the state that sent a packet
 * ??? this could be expensive -- it should be rate-limited to avoid DoS
 */
struct state *
find_sender(size_t packet_len, u_char *packet)
{
    int i;
    struct state *st;

    if (packet_len >= sizeof(struct isakmp_hdr))
        for (i = 0; i < STATE_TABLE_SIZE; i++)
            for (st = statetable[i]; st != NULL; st = st->st_hashchain_next)
                if (st->st_tpacket.ptr != NULL
                && st->st_tpacket.len == packet_len
                && memcmp(st->st_tpacket.ptr, packet, packet_len) == 0)
                    return st;

    return NULL;
}

struct state *
find_phase2_state_to_delete(const struct state *p1st
, u_int8_t protoid
, ipsec_spi_t spi
, bool *bogus)
{
    struct state *st;
    int i;

    *bogus = FALSE;
    for (i = 0; i < STATE_TABLE_SIZE; i++)
    {
        for (st = statetable[i]; st != NULL; st = st->st_hashchain_next)
        {
            if (IS_IPSEC_SA_ESTABLISHED(st->st_state)
            && p1st->st_connection->host_pair == st->st_connection->host_pair
            && same_peer_ids(p1st->st_connection, st->st_connection, NULL))
            {
                struct ipsec_proto_info *pr = protoid == PROTO_IPSEC_AH
                    ? &st->st_ah : &st->st_esp;

                if (pr->present)
                {
                    if (pr->attrs.spi == spi)
                        return st;
                    if (pr->our_spi == spi)
                        *bogus = TRUE;
                }
            }
        }
    }
    return NULL;
}

/* Find newest Phase 1 negotiation state object for suitable for connection c
 */
struct state *
find_phase1_state(const struct connection *c, lset_t ok_states)
{
    struct state
        *st,
        *best = NULL;
    int i;

    for (i = 0; i < STATE_TABLE_SIZE; i++)
        for (st = statetable[i]; st != NULL; st = st->st_hashchain_next)
            if (LHAS(ok_states, st->st_state)
            && c->host_pair == st->st_connection->host_pair
            && same_peer_ids(c, st->st_connection, NULL)
            && (best == NULL || best->st_serialno < st->st_serialno))
                best = st;

    return best;
}

void
state_eroute_usage(ip_subnet *ours, ip_subnet *his
, unsigned long count, time_t nw)
{
    struct state *st;
    int i;

    for (i = 0; i < STATE_TABLE_SIZE; i++)
    {
        for (st = statetable[i]; st != NULL; st = st->st_hashchain_next)
        {
            struct connection *c = st->st_connection;

            /* XXX spd-enum */
            if (IS_IPSEC_SA_ESTABLISHED(st->st_state)
                && c->spd.eroute_owner == st->st_serialno
                && c->spd.routing == RT_ROUTED_TUNNEL
                && samesubnet(&c->spd.this.client, ours)
                && samesubnet(&c->spd.that.client, his))
            {
                if (st->st_outbound_count != count)
                {
                    st->st_outbound_count = count;
                    st->st_outbound_time = nw;
                }
                return;
            }
        }
    }
    DBG(DBG_CONTROL,
        {
            char ourst[SUBNETTOT_BUF];
            char hist[SUBNETTOT_BUF];

            subnettot(ours, 0, ourst, sizeof(ourst));
            subnettot(his, 0, hist, sizeof(hist));
            DBG_log("unknown tunnel eroute %s -> %s found in scan"
                , ourst, hist);
        });
}

void fmt_state(struct state *st, time_t n
, char *state_buf, size_t state_buf_len
, char *state_buf2, size_t state_buf2_len)
{
    /* what the heck is interesting about a state? */
    const struct connection *c = st->st_connection;

    long delta = st->st_event->ev_time >= n
        ? (long)(st->st_event->ev_time - n)
        : -(long)(n - st->st_event->ev_time);

    char inst[CONN_INST_BUF];
    const char *np1 = c->newest_isakmp_sa == st->st_serialno
        ? "; newest ISAKMP" : "";
    const char *np2 = c->newest_ipsec_sa == st->st_serialno
        ? "; newest IPSEC" : "";
    /* XXX spd-enum */
    const char *eo = c->spd.eroute_owner == st->st_serialno
        ? "; eroute owner" : "";

    passert(st->st_event != 0);

    fmt_conn_instance(c, inst);

    snprintf(state_buf, state_buf_len
        , "#%lu: \"%s\"%s %s (%s); %s in %lds%s%s%s"
        , st->st_serialno
        , c->name, inst
        , enum_name(&state_names, st->st_state)
        , state_story[st->st_state - STATE_MAIN_R0]
        , enum_name(&timer_event_names, st->st_event->ev_type)
        , delta
        , np1, np2, eo);

    /* print out SPIs if SAs are established */
    if (state_buf2_len != 0)
        state_buf2[0] = '\0';   /* default to empty */
    if (IS_IPSEC_SA_ESTABLISHED(st->st_state))
    {

        bool tunnel;
        char buf[SATOT_BUF*6 + 2*20 + 1];
        const char *p_end = buf + sizeof(buf);
        char *p = buf;

#       define add_said(adst, aspi, aproto) { \
            ip_said s; \
            \
            initsaid(adst, aspi, aproto, &s); \
            if (p < p_end - 1) \
            { \
                *p++ = ' '; \
                p += satot(&s, 0, p, p_end - p) - 1; \
            } \
        }

#       define add_sa_info(st, inbound) { \
            u_int bytes; \
            time_t use_time; \
            \
            if (get_sa_info(st, inbound, &bytes, &use_time)) \
            { \
                p += snprintf(p, p_end - p, " (%'u bytes", bytes); \
                if (bytes > 0 && use_time != UNDEFINED_TIME) \
                    p += snprintf(p, p_end - p, ", %ds ago", (int)(now - use_time)); \
                p += snprintf(p, p_end - p, ")"); \
            } \
        }

        *p = '\0';
        if (st->st_ah.present)
        {
            add_said(&c->spd.that.host_addr, st->st_ah.attrs.spi, SA_AH);
            add_said(&c->spd.this.host_addr, st->st_ah.our_spi, SA_AH);
        }
        if (st->st_esp.present)
        {
            time_t now = time(NULL);

            add_said(&c->spd.that.host_addr, st->st_esp.attrs.spi, SA_ESP);
            add_sa_info(st, FALSE);
            add_said(&c->spd.this.host_addr, st->st_esp.our_spi, SA_ESP);
            add_sa_info(st, TRUE);
        }
        if (st->st_ipcomp.present)
        {
            add_said(&c->spd.that.host_addr, st->st_ipcomp.attrs.spi, SA_COMP);
            add_said(&c->spd.this.host_addr, st->st_ipcomp.our_spi, SA_COMP);
        }
#ifdef KLIPS
        tunnel =  st->st_ah.attrs.encapsulation == ENCAPSULATION_MODE_TUNNEL
               || st->st_esp.attrs.encapsulation == ENCAPSULATION_MODE_TUNNEL
               || st->st_ipcomp.attrs.encapsulation == ENCAPSULATION_MODE_TUNNEL;
        p += snprintf(p, p_end - p, "; %s", tunnel? "tunnel":"transport");
#endif

        snprintf(state_buf2, state_buf2_len
            , "#%lu: \"%s\"%s%s"
            , st->st_serialno
            , c->name, inst
            , buf);

#       undef add_said
#       undef add_sa_info
    }
}

/*
 * sorting logic is:
 *
 *  name
 *  type
 *  instance#
 *  isakmp_sa (XXX probably wrong)
 *
 */
static int
state_compare(const void *a, const void *b)
{
    const struct state *sap = *(const struct state *const *)a;
    struct connection *ca = sap->st_connection;
    const struct state *sbp = *(const struct state *const *)b;
    struct connection *cb = sbp->st_connection;

    /* DBG_log("comparing %s to %s", ca->name, cb->name); */

    return connection_compare(ca, cb);
}

void
show_states_status(const char *name)
{
    time_t n = now();
    int i;
    char state_buf[LOG_WIDTH];
    char state_buf2[LOG_WIDTH];
    int count;
    struct state **array;

    /* make count of states */
    count = 0;
    for (i = 0; i < STATE_TABLE_SIZE; i++)
    {
        struct state *st;

        for (st = statetable[i]; st != NULL; st = st->st_hashchain_next)
        {
            if (name == NULL || streq(name, st->st_connection->name))
                count++;
        }
    }

    /* build the array */
    array = alloc_bytes(sizeof(struct state *)*count, "state array");
    count = 0;
    for (i = 0; i < STATE_TABLE_SIZE; i++)
    {
        struct state *st;

        for (st = statetable[i]; st != NULL; st = st->st_hashchain_next)
        {
            if (name == NULL || streq(name, st->st_connection->name))
                array[count++]=st;
        }
    }

    /* sort it! */
    qsort(array, count, sizeof(struct state *), state_compare);

    /* now print sorted results */
    for (i = 0; i < count; i++)
    {
        struct state *st;

        st = array[i];

        fmt_state(st, n, state_buf, sizeof(state_buf)
                  , state_buf2, sizeof(state_buf2));
        whack_log(RC_COMMENT, state_buf);
        if (state_buf2[0] != '\0')
            whack_log(RC_COMMENT, state_buf2);

        /* show any associated pending Phase 2s */
        if (IS_PHASE1(st->st_state))
            show_pending_phase2(st->st_connection->host_pair, st);
    }
    if (count > 0)
        whack_log(RC_COMMENT, BLANK_FORMAT);    /* spacer */

    /* free the array */
    pfree(array);
}

/* Given that we've used up a range of unused CPI's,
 * search for a new range of currently unused ones.
 * Note: this is very expensive when not trivial!
 * If we can't find one easily, choose 0 (a bad SPI,
 * no matter what order) indicating failure.
 */
void
find_my_cpi_gap(cpi_t *latest_cpi, cpi_t *first_busy_cpi)
{
    int tries = 0;
    cpi_t base = *latest_cpi;
    cpi_t closest;
    int i;

startover:
    closest = ~0;       /* not close at all */
    for (i = 0; i < STATE_TABLE_SIZE; i++)
    {
        struct state *st;

        for (st = statetable[i]; st != NULL; st = st->st_hashchain_next)
        {
            if (st->st_ipcomp.present)
            {
                cpi_t c = ntohl(st->st_ipcomp.our_spi) - base;

                if (c < closest)
                {
                    if (c == 0)
                    {
                        /* oops: next spot is occupied; start over */
                        if (++tries == 20)
                        {
                            /* FAILURE */
                            *latest_cpi = *first_busy_cpi = 0;
                            return;
                        }
                        base++;
                        if (base > IPCOMP_LAST_NEGOTIATED)
                            base = IPCOMP_FIRST_NEGOTIATED;
                        goto startover; /* really a tail call */
                    }
                    closest = c;
                }
            }
        }
    }
    *latest_cpi = base; /* base is first in next free range */
    *first_busy_cpi = closest + base;   /* and this is the roof */
}

/* Muck with high-order 16 bits of this SPI in order to make
 * the corresponding SAID unique.
 * Its low-order 16 bits hold a well-known IPCOMP CPI.
 * Oh, and remember that SPIs are stored in network order.
 * Kludge!!!  So I name it with the non-English word "uniquify".
 * If we can't find one easily, return 0 (a bad SPI,
 * no matter what order) indicating failure.
 */
ipsec_spi_t
uniquify_his_cpi(ipsec_spi_t cpi, struct state *st)
{
    int tries = 0;
    int i;

startover:

    /* network order makes first two bytes our target */
    get_rnd_bytes((u_char *)&cpi, 2);

    /* Make sure that the result is unique.
     * Hard work.  If there is no unique value, we'll loop forever!
     */
    for (i = 0; i < STATE_TABLE_SIZE; i++)
    {
        struct state *s;

        for (s = statetable[i]; s != NULL; s = s->st_hashchain_next)
        {
            if (s->st_ipcomp.present
            && sameaddr(&s->st_connection->spd.that.host_addr
              , &st->st_connection->spd.that.host_addr)
            && cpi == s->st_ipcomp.attrs.spi)
            {
                if (++tries == 20)
                    return 0;   /* FAILURE */
                goto startover;
            }
        }
    }
    return cpi;
}

/*
 * Local Variables:
 * c-basic-offset:4
 * End:
 */