st->pad = 8 - (st->len % 8);
    st->biglen = st->len + st->pad;
    pktin.length = st->len - 5;

    if (pktin.maxlen < st->biglen) {
	pktin.maxlen = st->biglen;
	pktin.data = (pktin.data == NULL ? smalloc(st->biglen+APIEXTRA) :
	              srealloc(pktin.data, st->biglen+APIEXTRA));
	if (!pktin.data)
	    fatalbox("Out of memory");
    }

    st->to_read = st->biglen;
    st->p = pktin.data;
    while (st->to_read > 0) {

	debug(("\r\n"));
#endif
	zlib_decompress_block(pktin.body-1, pktin.length+1,
			      &decompblk, &decomplen);

	if (pktin.maxlen < st->pad + decomplen) {
	    pktin.maxlen = st->pad + decomplen;
	    pktin.data = srealloc(pktin.data, pktin.maxlen+APIEXTRA);
	    if (!pktin.data)
		fatalbox("Out of memory");
	}

	memcpy(pktin.body-1, decompblk, decomplen);
	sfree(decompblk);
	pktin.length = decomplen-1;
#if 0
	debug(("Packet payload post-decompression:\n"));
	for (i = -1; i < pktin.length; i++)
	    debug(("  %02x", (unsigned char)pktin.body[i]));
	debug(("\r\n"));
#endif

    else
        st->cipherblk = 8;
    if (st->cipherblk < 8)
        st->cipherblk = 8;

    if (pktin.maxlen < st->cipherblk) {
	pktin.maxlen = st->cipherblk;
	pktin.data = (pktin.data == NULL ? smalloc(st->cipherblk+APIEXTRA) :
	              srealloc(pktin.data, st->cipherblk+APIEXTRA));
	if (!pktin.data)
	    fatalbox("Out of memory");
    }

    /*
     * Acquire and decrypt the first block of the packet. This will
     * contain the length and padding details.

    st->maclen = scmac ? scmac->len : 0;

    /*
     * Adjust memory allocation if packet is too big.
     */
    if (pktin.maxlen < st->packetlen+st->maclen) {
	pktin.maxlen = st->packetlen+st->maclen;
	pktin.data = (pktin.data == NULL ? smalloc(pktin.maxlen+APIEXTRA) :
	              srealloc(pktin.data, pktin.maxlen+APIEXTRA));
	if (!pktin.data)
	    fatalbox("Out of memory");
    }

    /*
     * Read and decrypt the remainder of the packet.
     */

    {
	unsigned char *newpayload;
	int newlen;
	if (sccomp && sccomp->decompress(pktin.data+5, pktin.length-5,
					 &newpayload, &newlen)) {
	    if (pktin.maxlen < newlen+5) {
		pktin.maxlen = newlen+5;
		pktin.data = (pktin.data == NULL ? smalloc(pktin.maxlen+APIEXTRA) :
			      srealloc(pktin.data, pktin.maxlen+APIEXTRA));
		if (!pktin.data)
		    fatalbox("Out of memory");
	    }
	    pktin.length = 5 + newlen;
	    memcpy(pktin.data+5, newpayload, newlen);
#if 0
	    debug(("Post-decompression payload:\r\n"));
	    for (st->i = 0; st->i < newlen; st->i++)
		debug(("  %02x", (unsigned char)pktin.data[5+st->i]));
	    debug(("\r\n"));
#endif

	    sfree(newpayload);
	}
    }

    pktin.savedpos = 6;
    pktin.type = pktin.data[5];

    if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG)

    pktout.length = len-5;
    if (pktout.maxlen < biglen) {
	pktout.maxlen = biglen;
#ifdef MSCRYPTOAPI
	/* Allocate enough buffer space for extra block
	 * for MS CryptEncrypt() */
	pktout.data = (pktout.data == NULL ? smalloc(biglen+12) :
		       srealloc(pktout.data, biglen+12));
#else
	pktout.data = (pktout.data == NULL ? smalloc(biglen+4) :
		       srealloc(pktout.data, biglen+4));
#endif
	if (!pktout.data)
	    fatalbox("Out of memory");
    }
    pktout.body = pktout.data+4+pad+1;
}

	    debug(("  %02x", (unsigned char)pktout.body[i]));
	debug(("\r\n"));
#endif
	zlib_compress_block(pktout.body-1, pktout.length+1,
			    &compblk, &complen);
	ssh1_pktout_size(complen-1);
	memcpy(pktout.body-1, compblk, complen);
	sfree(compblk);
#if 0
	debug(("Packet payload post-compression:\n"));
	for (i = -1; i < pktout.length; i++)
	    debug(("  %02x", (unsigned char)pktout.body[i]));
	debug(("\r\n"));
#endif
    }

/*
 * SSH2 packet construction functions.
 */
static void ssh2_pkt_adddata(void *data, int len) {
    pktout.length += len;
    if (pktout.maxlen < pktout.length) {
        pktout.maxlen = pktout.length + 256;
	pktout.data = (pktout.data == NULL ? smalloc(pktout.maxlen+APIEXTRA) :
                       srealloc(pktout.data, pktout.maxlen+APIEXTRA));
        if (!pktout.data)
            fatalbox("Out of memory");
    }
    memcpy(pktout.data+pktout.length-len, data, len);
}
static void ssh2_pkt_addbyte(unsigned char byte) {
    ssh2_pkt_adddata(&byte, 1);

static void ssh2_pkt_addstring(char *data) {
    ssh2_pkt_addstring_start();
    ssh2_pkt_addstring_str(data);
}
static char *ssh2_mpint_fmt(Bignum b, int *len) {
    unsigned char *p;
    int i, n = b[0];
    p = smalloc(n * 2 + 1);
    if (!p)
        fatalbox("out of memory");
    p[0] = 0;
    for (i = 0; i < n; i++) {
        p[i*2+1] = (b[n-i] >> 8) & 0xFF;
        p[i*2+2] = (b[n-i]     ) & 0xFF;
    }
    i = 0;
    while (p[i] == 0 && (p[i+1] & 0x80) == 0)
        i++;
    memmove(p, p+i, n*2+1-i);
    *len = n*2+1-i;
    return p;
}
static void ssh2_pkt_addmp(Bignum b) {
    unsigned char *p;
    int len;
    p = ssh2_mpint_fmt(b, &len);
    ssh2_pkt_addstring_start();
    ssh2_pkt_addstring_data(p, len);
    sfree(p);
}
static void ssh2_pkt_send(void) {
    int cipherblk, maclen, padding, i;
    static unsigned long outgoing_sequence = 0;

    /*
     * Compress packet payload.

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

    /*
     * Add padding. At least four bytes, and must also bring total
     * length (minus MAC) up to a multiple of the block size.
     */

    unsigned char *p;
    int i, len;
    p = ssh2_mpint_fmt(b, &len);
    debug(("%s", string));
    for (i = 0; i < len; i++)
        debug((" %02x", p[i]));
    debug(("\r\n"));
    sfree(p);
}
#endif

static void sha_mpint(SHA_State *s, Bignum b) {
    unsigned char *p;
    int len;
    p = ssh2_mpint_fmt(b, &len);
    sha_string(s, p, len);
    sfree(p);
}

/*
 * SSH2 packet decode functions.
 */
static unsigned long ssh2_pkt_getuint32(void) {
    unsigned long value;

    SockAddr addr;
    char *err;
#ifdef FWHACK
    char *FWhost;
    int FWport;
#endif

    savedhost = smalloc(1+strlen(host));
    if (!savedhost)
	fatalbox("Out of memory");
    strcpy(savedhost, host);

    if (port < 0)
	port = 22;		       /* default ssh port */
    savedport = port;

    MD5Final(session_id, &md5c);

    for (i=0; i<32; i++)
	session_key[i] = random_byte();

    len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);

    rsabuf = smalloc(len);
    if (!rsabuf)
	fatalbox("Out of memory");

    /*
     * Verify the host key.
     */
    {
        /*
         * First format the key into a string.
         */
        int len = rsastr_len(&hostkey);
        char fingerprint[100];
        char *keystr = smalloc(len);
        if (!keystr)
            fatalbox("Out of memory");
        rsastr_fmt(keystr, &hostkey);
        rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
        verify_ssh_host_key(savedhost, savedport, "rsa", keystr, fingerprint);
        sfree(keystr);
    }

    for (i=0; i<32; i++) {
	rsabuf[i] = session_key[i];
	if (i < 16)
	    rsabuf[i] ^= session_id[i];
    }

                PKT_CHAR, (len*8) >> 8, PKT_CHAR, (len*8) & 0xFF,
                PKT_DATA, rsabuf, len,
                PKT_INT, 0,
                PKT_END);

    logevent("Trying to enable encryption...");

    sfree(rsabuf);

    cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
             cipher_type == SSH_CIPHER_DES ? &ssh_des :
             &ssh_3des;
    cipher->sesskey(session_key);

    crWaitUntil(ispkt);

                        int len, retlen;
                        len = 1 + 4;   /* message type, bit count */
                        len += ssh1_bignum_length(key.exponent);
                        len += ssh1_bignum_length(key.modulus);
                        len += ssh1_bignum_length(challenge);
                        len += 16;     /* session id */
                        len += 4;      /* response format */
                        agentreq = smalloc(4 + len);
                        PUT_32BIT(agentreq, len);
                        q = agentreq + 4;
                        *q++ = SSH_AGENTC_RSA_CHALLENGE;
                        PUT_32BIT(q, ssh1_bignum_bitcount(key.modulus));
                        q += 4;
                        q += ssh1_write_bignum(q, key.exponent);
                        q += ssh1_write_bignum(q, key.modulus);
                        q += ssh1_write_bignum(q, challenge);
                        memcpy(q, session_id, 16); q += 16;
                        PUT_32BIT(q, 1);   /* response format */
                        agent_query(agentreq, len+4, &ret, &retlen);
                        sfree(agentreq);
                        if (ret) {
                            if (ret[4] == SSH_AGENT_RSA_RESPONSE) {
                                logevent("Sending Pageant's response");
                                send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
                                            PKT_DATA, ret+5, 16, PKT_END);
                                sfree(ret);
                                crWaitUntil(ispkt);
                                if (pktin.type == SSH1_SMSG_SUCCESS) {
                                    logevent("Pageant's response accepted");
                                    if (flags & FLAG_VERBOSE) {
                                        c_write("Authenticated using RSA key \"",
                                                29);
                                        c_write(commentp, commentlen);
                                        c_write("\" from agent\r\n", 14);
                                    }
                                    authed = TRUE;
                                } else
                                    logevent("Pageant's response not accepted");
                            } else {
                                logevent("Pageant failed to answer challenge");
                                sfree(ret);
                            }
                        } else {
                            logevent("No reply received from Pageant");
                        }
                    }
                    freebn(key.exponent);
                    freebn(key.modulus);

                c_write("Trying public key authentication.\r\n", 35);
            if (!rsakey_encrypted(cfg.keyfile, &comment)) {
                if (flags & FLAG_VERBOSE)
                    c_write("No passphrase required.\r\n", 25);
                goto tryauth;
            }
            sprintf(prompt, "Passphrase for key \"%.100s\": ", comment);
            sfree(comment);
        }

	if (ssh_get_password) {
	    if (!ssh_get_password(prompt, password, sizeof(password))) {
                /*
                 * get_password failed to get a password (for
                 * example because one was supplied on the command

		} else {
		    i = 1;
		    for (c = first234(ssh_channels, &e); c; c = next234(&e)) {
			if (c->localid > i)
			    break;     /* found a free number */
			i = c->localid + 1;
		    }
		    c = smalloc(sizeof(struct ssh_channel));
		    c->remoteid = GET_32BIT(pktin.body);
		    c->localid = i;
		    c->closes = 0;
		    c->type = SSH1_SMSG_AGENT_OPEN;/* identify channel type */
		    c->u.a.lensofar = 0;
		    add234(ssh_channels, c);
		    send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,

                if (c) {
                    int closetype;
                    closetype = (pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
                    send_packet(pktin.type, PKT_INT, c->remoteid, PKT_END);
                    c->closes |= closetype;
                    if (c->closes == 3) {
                        del234(ssh_channels, c);
                        sfree(c);
                    }
                }
            } else if (pktin.type == SSH1_MSG_CHANNEL_DATA) {
                /* Data sent down one of our channels. */
                int i = GET_32BIT(pktin.body);
                int len = GET_32BIT(pktin.body+4);
                unsigned char *p = pktin.body+8;

                            if (c->u.a.lensofar < 4) {
                                int l = min(4 - c->u.a.lensofar, len);
                                memcpy(c->u.a.msglen + c->u.a.lensofar, p, l);
                                p += l; len -= l; c->u.a.lensofar += l;
                            }
                            if (c->u.a.lensofar == 4) {
                                c->u.a.totallen = 4 + GET_32BIT(c->u.a.msglen);
                                c->u.a.message = smalloc(c->u.a.totallen);
                                memcpy(c->u.a.message, c->u.a.msglen, 4);
                            }
                            if (c->u.a.lensofar >= 4 && len > 0) {
                                int l = min(c->u.a.totallen - c->u.a.lensofar, len);
                                memcpy(c->u.a.message + c->u.a.lensofar, p, l);
                                p += l; len -= l; c->u.a.lensofar += l;
                            }

                                }
                                send_packet(SSH1_MSG_CHANNEL_DATA,
                                            PKT_INT, c->remoteid,
                                            PKT_INT, replylen,
                                            PKT_DATA, sentreply, replylen,
                                            PKT_END);
                                if (reply)
                                    sfree(reply);
                                sfree(c->u.a.message);
                                c->u.a.lensofar = 0;
                            }
                        }
                        break;
                    }
                }                
	    } else if (pktin.type == SSH1_SMSG_SUCCESS) {

     */
    keystr = hostkey->fmtkey(hkey);
    fingerprint = hostkey->fingerprint(hkey);
    verify_ssh_host_key(savedhost, savedport, hostkey->keytype,
                        keystr, fingerprint);
    logevent("Host key fingerprint is:");
    logevent(fingerprint);
    sfree(fingerprint);
    sfree(keystr);
    hostkey->freekey(hkey);

    /*
     * Send SSH2_MSG_NEWKEYS.
     */
    ssh2_pkt_init(SSH2_MSG_NEWKEYS);
    ssh2_pkt_send();

     * connection protocol will automatically have started at this
     * point; there's no need to send SERVICE_REQUEST.
     */

    /*
     * So now create a channel with a session in it.
     */
    mainchan = smalloc(sizeof(struct ssh_channel));
    mainchan->localid = 100;           /* as good as any */
    ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
    ssh2_pkt_addstring("session");
    ssh2_pkt_adduint32(mainchan->localid);
    ssh2_pkt_adduint32(0x8000UL);  /* our window size */
    ssh2_pkt_adduint32(0x4000UL);  /* our max pkt size */
    ssh2_pkt_send();