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/* write_packet.c */
/* lsh, an implementation of the ssh protocol
*
* Copyright (C) 2003 Niels Mller
*
* 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.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <assert.h>
#include <nettle/macros.h>
#include "connection.h"
#include "format.h"
#include "lsh_string.h"
#include "werror.h"
#include "xalloc.h"
#include "write_packet.c.x"
/* GABA:
(class
(name write_packet)
(super abstract_write_pipe)
(vars
(connection object ssh_connection)
(random object randomness)
(sequence_number . uint32_t)))
*/
static void
do_write_packet(struct abstract_write *s,
struct lsh_string *packet)
{
CAST(write_packet, self, s);
struct ssh_connection *connection = self->connection;
uint32_t block_size;
uint32_t new_size;
uint8_t padding_length;
uint32_t padding;
uint32_t mac_length;
uint32_t mac;
uint32_t length = lsh_string_length(packet);
assert(length);
/* Deflate, pad, mac, encrypt. */
if (connection->send_compress)
{
packet = CODEC(connection->send_compress, packet, 1);
assert(packet);
length = lsh_string_length(packet);
}
block_size = connection->send_crypto
? connection->send_crypto->block_size : 8;
mac_length = connection->send_mac
? connection->send_mac->mac_size : 0;
/* new_size is (length + 9) rounded up to a multiple of
* block_size */
new_size = block_size * (1 + (8 + length) / block_size);
padding_length = new_size - length - 5;
assert(padding_length >= 4);
packet = ssh_format("%i%c%lfS%lr%lr",
length + padding_length + 1,
padding_length,
packet,
padding_length, &padding,
mac_length, &mac);
assert(new_size + mac_length == lsh_string_length(packet));
lsh_string_write_random(packet, padding, self->random, padding_length);
if (connection->send_mac)
{
uint8_t s[4];
assert(new_size == mac);
WRITE_UINT32(s, self->sequence_number);
MAC_UPDATE(connection->send_mac, 4, s);
MAC_UPDATE(connection->send_mac, new_size, lsh_string_data(packet));
MAC_DIGEST(connection->send_mac, packet, mac);
}
if (connection->send_crypto)
CRYPT(connection->send_crypto, new_size, packet, 0, packet, 0);
self->sequence_number++;
A_WRITE(self->super.next, packet);
}
struct abstract_write *
make_write_packet(struct ssh_connection *connection,
struct randomness *random,
struct abstract_write *next)
{
NEW(write_packet, self);
self->super.super.write = do_write_packet;
self->super.next = next;
self->connection = connection;
self->random = random;
self->sequence_number = 0;
return &self->super.super;
}
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