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/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
* Interface for the packet protocol functions.
*
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
*/
/* RCSID("$OpenBSD: packet.h,v 1.17 2000/09/07 20:27:52 deraadt Exp $"); */
#ifndef PACKET_H
#define PACKET_H
#include <openssl/bn.h>
/*
* Sets the socket used for communication. Disables encryption until
* packet_set_encryption_key is called. It is permissible that fd_in and
* fd_out are the same descriptor; in that case it is assumed to be a socket.
*/
void packet_set_connection(int fd_in, int fd_out);
/* Puts the connection file descriptors into non-blocking mode. */
void packet_set_nonblocking(void);
/* Returns the file descriptor used for input. */
int packet_get_connection_in(void);
/* Returns the file descriptor used for output. */
int packet_get_connection_out(void);
/*
* Closes the connection (both descriptors) and clears and frees internal
* data structures.
*/
void packet_close(void);
/*
* Causes any further packets to be encrypted using the given key. The same
* key is used for both sending and reception. However, both directions are
* encrypted independently of each other. Cipher types are defined in ssh.h.
*/
void
packet_set_encryption_key(const unsigned char *key, unsigned int keylen,
int cipher_type);
/*
* Sets remote side protocol flags for the current connection. This can be
* called at any time.
*/
void packet_set_protocol_flags(unsigned int flags);
/* Returns the remote protocol flags set earlier by the above function. */
unsigned int packet_get_protocol_flags(void);
/* Enables compression in both directions starting from the next packet. */
void packet_start_compression(int level);
/*
* Informs that the current session is interactive. Sets IP flags for
* optimal performance in interactive use.
*/
void packet_set_interactive(int interactive, int keepalives);
/* Returns true if the current connection is interactive. */
int packet_is_interactive(void);
/* Starts constructing a packet to send. */
void packet_start(int type);
/* Appends a character to the packet data. */
void packet_put_char(int ch);
/* Appends an integer to the packet data. */
void packet_put_int(unsigned int value);
/* Appends an arbitrary precision integer to packet data. */
void packet_put_bignum(BIGNUM * value);
void packet_put_bignum2(BIGNUM * value);
/* Appends a string to packet data. */
void packet_put_string(const char *buf, unsigned int len);
void packet_put_cstring(const char *str);
void packet_put_raw(const char *buf, unsigned int len);
/*
* Finalizes and sends the packet. If the encryption key has been set,
* encrypts the packet before sending.
*/
void packet_send(void);
/* Waits until a packet has been received, and returns its type. */
int packet_read(int *payload_len_ptr);
/*
* Waits until a packet has been received, verifies that its type matches
* that given, and gives a fatal error and exits if there is a mismatch.
*/
void packet_read_expect(int *payload_len_ptr, int type);
/*
* Checks if a full packet is available in the data received so far via
* packet_process_incoming. If so, reads the packet; otherwise returns
* SSH_MSG_NONE. This does not wait for data from the connection.
* SSH_MSG_DISCONNECT is handled specially here. Also, SSH_MSG_IGNORE
* messages are skipped by this function and are never returned to higher
* levels.
*/
int packet_read_poll(int *packet_len_ptr);
/*
* Buffers the given amount of input characters. This is intended to be used
* together with packet_read_poll.
*/
void packet_process_incoming(const char *buf, unsigned int len);
/* Returns a character (0-255) from the packet data. */
unsigned int packet_get_char(void);
/* Returns an integer from the packet data. */
unsigned int packet_get_int(void);
/*
* Returns an arbitrary precision integer from the packet data. The integer
* must have been initialized before this call.
*/
void packet_get_bignum(BIGNUM * value, int *length_ptr);
void packet_get_bignum2(BIGNUM * value, int *length_ptr);
char *packet_get_raw(int *length_ptr);
/*
* Returns a string from the packet data. The string is allocated using
* xmalloc; it is the responsibility of the calling program to free it when
* no longer needed. The length_ptr argument may be NULL, or point to an
* integer into which the length of the string is stored.
*/
char *packet_get_string(unsigned int *length_ptr);
/*
* Logs the error in syslog using LOG_INFO, constructs and sends a disconnect
* packet, closes the connection, and exits. This function never returns.
* The error message should not contain a newline. The total length of the
* message must not exceed 1024 bytes.
*/
void packet_disconnect(const char *fmt,...) __attribute__((format(printf, 1, 2)));
/*
* Sends a diagnostic message to the other side. This message can be sent at
* any time (but not while constructing another message). The message is
* printed immediately, but only if the client is being executed in verbose
* mode. These messages are primarily intended to ease debugging
* authentication problems. The total length of the message must not exceed
* 1024 bytes. This will automatically call packet_write_wait. If the
* remote side protocol flags do not indicate that it supports SSH_MSG_DEBUG,
* this will do nothing.
*/
void packet_send_debug(const char *fmt,...) __attribute__((format(printf, 1, 2)));
/* Checks if there is any buffered output, and tries to write some of the output. */
void packet_write_poll(void);
/* Waits until all pending output data has been written. */
void packet_write_wait(void);
/* Returns true if there is buffered data to write to the connection. */
int packet_have_data_to_write(void);
/* Returns true if there is not too much data to write to the connection. */
int packet_not_very_much_data_to_write(void);
/* maximum packet size, requested by client with SSH_CMSG_MAX_PACKET_SIZE */
extern int max_packet_size;
int packet_set_maxsize(int s);
#define packet_get_maxsize() max_packet_size
/* Stores tty modes from the fd into current packet. */
void tty_make_modes(int fd);
/* Parses tty modes for the fd from the current packet. */
void tty_parse_modes(int fd, int *n_bytes_ptr);
#define packet_integrity_check(payload_len, expected_len, type) \
do { \
int _p = (payload_len), _e = (expected_len); \
if (_p != _e) { \
log("Packet integrity error (%d != %d) at %s:%d", \
_p, _e, __FILE__, __LINE__); \
packet_disconnect("Packet integrity error. (%d)", (type)); \
} \
} while (0)
#define packet_done() \
do { \
int _len = packet_remaining(); \
if (_len > 0) { \
log("Packet integrity error (%d bytes remaining) at %s:%d", \
_len ,__FILE__, __LINE__); \
packet_disconnect("Packet integrity error."); \
} \
} while (0)
/* remote host is connected via a socket/ipv4 */
int packet_connection_is_on_socket(void);
int packet_connection_is_ipv4(void);
/* enable SSH2 packet format */
void packet_set_ssh2_format(void);
/* returns remaining payload bytes */
int packet_remaining(void);
#endif /* PACKET_H */
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