const static struct ssh_mac *macs[] = {
    &ssh_sha1, &ssh_md5, &ssh_mac_none
};
const static struct ssh_mac *buggymacs[] = {
    &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
};

static void *ssh_comp_none_init(void)
{
    return NULL;
}
static void ssh_comp_none_cleanup(void *handle)
{
}
static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
			       unsigned char **outblock, int *outlen)
{
    return 0;
}
static int ssh_comp_none_disable(void *handle)
{
    return 0;
}
const static struct ssh_compress ssh_comp_none = {
    "none",
    ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
    ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
    ssh_comp_none_disable, NULL
};
extern const struct ssh_compress ssh_zlib;
const static struct ssh_compress *compressions[] = {
    &ssh_zlib, &ssh_comp_none
};

enum {				       /* channel types */

    void *v1_cipher_ctx;
    void *crcda_ctx;
    const struct ssh2_cipher *cscipher, *sccipher;
    void *cs_cipher_ctx, *sc_cipher_ctx;
    const struct ssh_mac *csmac, *scmac;
    void *cs_mac_ctx, *sc_mac_ctx;
    const struct ssh_compress *cscomp, *sccomp;
    void *cs_comp_ctx, *sc_comp_ctx;
    const struct ssh_kex *kex;
    const struct ssh_signkey *hostkey;
    unsigned char v2_session_id[20];
    void *kex_ctx;

    char *savedhost;
    int savedport;

    }

    ssh->pktin.body = ssh->pktin.data + st->pad + 1;

    if (ssh->v1_compressing) {
	unsigned char *decompblk;
	int decomplen;
	zlib_decompress_block(ssh->sc_comp_ctx,
			      ssh->pktin.body - 1, ssh->pktin.length + 1,
			      &decompblk, &decomplen);

	if (ssh->pktin.maxlen < st->pad + decomplen) {
	    ssh->pktin.maxlen = st->pad + decomplen;
	    ssh->pktin.data = srealloc(ssh->pktin.data,
				       ssh->pktin.maxlen + APIEXTRA);
	    ssh->pktin.body = ssh->pktin.data + st->pad + 1;

    /*
     * Decompress packet payload.
     */
    {
	unsigned char *newpayload;
	int newlen;
	if (ssh->sccomp &&
	    ssh->sccomp->decompress(ssh->sc_comp_ctx,
				    ssh->pktin.data + 5, ssh->pktin.length - 5,
				    &newpayload, &newlen)) {
	    if (ssh->pktin.maxlen < newlen + 5) {
		ssh->pktin.maxlen = newlen + 5;
		ssh->pktin.data = srealloc(ssh->pktin.data,
					   ssh->pktin.maxlen + APIEXTRA);
	    }
	    ssh->pktin.length = 5 + newlen;

    log_packet(PKT_OUTGOING, ssh->pktout.type, ssh1_pkt_type(ssh->pktout.type),
	       ssh->pktout.body, ssh->pktout.length);

    if (ssh->v1_compressing) {
	unsigned char *compblk;
	int complen;
	zlib_compress_block(ssh->cs_comp_ctx,
			    ssh->pktout.body - 1, ssh->pktout.length + 1,
			    &compblk, &complen);
	ssh1_pktout_size(ssh, complen - 1);
	memcpy(ssh->pktout.body - 1, compblk, complen);
	sfree(compblk);
    }

    len = ssh->pktout.length + 5;	       /* type and CRC */

    /*
     * Compress packet payload.
     */
    {
	unsigned char *newpayload;
	int newlen;
	if (ssh->cscomp &&
	    ssh->cscomp->compress(ssh->cs_comp_ctx, ssh->pktout.data + 5,
				  ssh->pktout.length - 5,
				  &newpayload, &newlen)) {
	    ssh->pktout.length = 5;
	    ssh2_pkt_adddata(ssh, newpayload, newlen);
	    sfree(newpayload);
	}
    }

	    bombout(("Protocol confusion"));
	    crReturnV;
	} else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
	    c_write_str(ssh, "Server refused to compress\r\n");
	}
	logevent("Started compression");
	ssh->v1_compressing = TRUE;
	ssh->cs_comp_ctx = zlib_compress_init();
	logevent("Initialised zlib (RFC1950) compression");
	ssh->sc_comp_ctx = zlib_decompress_init();
	logevent("Initialised zlib (RFC1950) decompression");
    }

    /*
     * Start the shell or command.
     * 
     * Special case: if the first-choice command is an SSH2
     * subsystem (hence not usable here) and the second choice

    ssh->cs_mac_ctx = ssh->csmac->make_context();

    if (ssh->sc_mac_ctx)
	ssh->scmac->free_context(ssh->sc_mac_ctx);
    ssh->scmac = s->scmac_tobe;
    ssh->sc_mac_ctx = ssh->scmac->make_context();

    if (ssh->cs_comp_ctx)
	ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
    ssh->cscomp = s->cscomp_tobe;
    ssh->cs_comp_ctx = ssh->cscomp->compress_init();

    if (ssh->sc_comp_ctx)
	ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
    ssh->sccomp = s->sccomp_tobe;
    ssh->sc_comp_ctx = ssh->sccomp->decompress_init();

    /*
     * Set IVs after keys. Here we use the exchange hash from the
     * _first_ key exchange.
     */
    {
	unsigned char keyspace[40];
	if (s->first_kex)

	char buf[256];
	sprintf(buf, "Initialised %.200s client->server encryption",
		ssh->cscipher->text_name);
	logevent(buf);
	sprintf(buf, "Initialised %.200s server->client encryption",
		ssh->sccipher->text_name);
	logevent(buf);
	if (ssh->cscomp->text_name) {
	    sprintf(buf, "Initialised %.200s compression",
		    ssh->cscomp->text_name);
	    logevent(buf);
	}
	if (ssh->sccomp->text_name) {
	    sprintf(buf, "Initialised %.200s decompression",
		    ssh->sccomp->text_name);
	    logevent(buf);
	}
    }


    /*
     * If this is the first key exchange phase, we must pass the
     * SSH2_MSG_NEWKEYS packet to the next layer, not because it
     * wants to see it but because it will need time to initialise

			 * so we can guarantee to get this string
			 * exactly the length we want it. The
			 * compression-disabling routine should
			 * return an integer indicating how many
			 * bytes we should adjust our string length
			 * by.
			 */
			stringlen -= 
			    ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
		    }
		    ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
		    ssh2_pkt_addstring_start(ssh);
		    for (i = 0; i < stringlen; i++) {
			char c = (char) random_byte();
			ssh2_pkt_addstring_data(ssh, &c, 1);
		    }

    ssh->sccipher = NULL;
    ssh->sc_cipher_ctx = NULL;
    ssh->csmac = NULL;
    ssh->sc_mac_ctx = NULL;
    ssh->scmac = NULL;
    ssh->sc_mac_ctx = NULL;
    ssh->cscomp = NULL;
    ssh->cs_comp_ctx = NULL;
    ssh->sccomp = NULL;
    ssh->sc_comp_ctx = NULL;
    ssh->kex = NULL;
    ssh->hostkey = NULL;
    ssh->exitcode = -1;
    ssh->state = SSH_STATE_PREPACKET;
    ssh->size_needed = FALSE;
    ssh->eof_needed = FALSE;
    {