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