path: root/packet.h
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Diffstat (limited to 'packet.h')
1 files changed, 166 insertions, 0 deletions
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+Author: Tatu Ylonen <>
+Copyright (c) 1995 Tatu Ylonen <>, Espoo, Finland
+ All rights reserved
+Created: Sat Mar 18 02:02:14 1995 ylo
+Interface for the packet protocol functions.
+/* RCSID("$Id: packet.h,v 1.1 1999/10/27 03:42:44 damien 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, int is_client);
+/* 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);
+/* Appends a string to packet data. */
+void packet_put_string(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);
+/* 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, ...);
+/* 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, ...);
+/* 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);
+/* 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)
+#endif /* PACKET_H */