2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * Interface for the packet protocol functions.
7 * As far as I am concerned, the code I have written for this software
8 * can be used freely for any purpose. Any derived versions of this
9 * software must be clearly marked as such, and if the derived work is
10 * incompatible with the protocol description in the RFC file, it must be
11 * called by a name other than "ssh" or "Secure Shell".
14 /* RCSID("$OpenBSD: packet.h,v 1.19 2001/01/13 18:32:50 markus Exp $"); */
19 #include <openssl/bn.h>
22 * Sets the socket used for communication. Disables encryption until
23 * packet_set_encryption_key is called. It is permissible that fd_in and
24 * fd_out are the same descriptor; in that case it is assumed to be a socket.
26 void packet_set_connection(int fd_in, int fd_out);
28 /* Puts the connection file descriptors into non-blocking mode. */
29 void packet_set_nonblocking(void);
31 /* Returns the file descriptor used for input. */
32 int packet_get_connection_in(void);
34 /* Returns the file descriptor used for output. */
35 int packet_get_connection_out(void);
38 * Closes the connection (both descriptors) and clears and frees internal
41 void packet_close(void);
44 * Causes any further packets to be encrypted using the given key. The same
45 * key is used for both sending and reception. However, both directions are
46 * encrypted independently of each other. Cipher types are defined in ssh.h.
49 packet_set_encryption_key(const u_char *key, u_int keylen,
53 * Sets remote side protocol flags for the current connection. This can be
56 void packet_set_protocol_flags(u_int flags);
58 /* Returns the remote protocol flags set earlier by the above function. */
59 u_int packet_get_protocol_flags(void);
61 /* Enables compression in both directions starting from the next packet. */
62 void packet_start_compression(int level);
65 * Informs that the current session is interactive. Sets IP flags for
66 * optimal performance in interactive use.
68 void packet_set_interactive(int interactive);
70 /* Returns true if the current connection is interactive. */
71 int packet_is_interactive(void);
73 /* Starts constructing a packet to send. */
74 void packet_start(int type);
76 /* Appends a character to the packet data. */
77 void packet_put_char(int ch);
79 /* Appends an integer to the packet data. */
80 void packet_put_int(u_int value);
82 /* Appends an arbitrary precision integer to packet data. */
83 void packet_put_bignum(BIGNUM * value);
84 void packet_put_bignum2(BIGNUM * value);
86 /* Appends a string to packet data. */
87 void packet_put_string(const char *buf, u_int len);
88 void packet_put_cstring(const char *str);
89 void packet_put_raw(const char *buf, u_int len);
92 * Finalizes and sends the packet. If the encryption key has been set,
93 * encrypts the packet before sending.
95 void packet_send(void);
97 /* Waits until a packet has been received, and returns its type. */
98 int packet_read(int *payload_len_ptr);
101 * Waits until a packet has been received, verifies that its type matches
102 * that given, and gives a fatal error and exits if there is a mismatch.
104 void packet_read_expect(int *payload_len_ptr, int type);
107 * Checks if a full packet is available in the data received so far via
108 * packet_process_incoming. If so, reads the packet; otherwise returns
109 * SSH_MSG_NONE. This does not wait for data from the connection.
110 * SSH_MSG_DISCONNECT is handled specially here. Also, SSH_MSG_IGNORE
111 * messages are skipped by this function and are never returned to higher
114 int packet_read_poll(int *packet_len_ptr);
117 * Buffers the given amount of input characters. This is intended to be used
118 * together with packet_read_poll.
120 void packet_process_incoming(const char *buf, u_int len);
122 /* Returns a character (0-255) from the packet data. */
123 u_int packet_get_char(void);
125 /* Returns an integer from the packet data. */
126 u_int packet_get_int(void);
129 * Returns an arbitrary precision integer from the packet data. The integer
130 * must have been initialized before this call.
132 void packet_get_bignum(BIGNUM * value, int *length_ptr);
133 void packet_get_bignum2(BIGNUM * value, int *length_ptr);
134 char *packet_get_raw(int *length_ptr);
137 * Returns a string from the packet data. The string is allocated using
138 * xmalloc; it is the responsibility of the calling program to free it when
139 * no longer needed. The length_ptr argument may be NULL, or point to an
140 * integer into which the length of the string is stored.
142 char *packet_get_string(u_int *length_ptr);
145 * Logs the error in syslog using LOG_INFO, constructs and sends a disconnect
146 * packet, closes the connection, and exits. This function never returns.
147 * The error message should not contain a newline. The total length of the
148 * message must not exceed 1024 bytes.
150 void packet_disconnect(const char *fmt,...) __attribute__((format(printf, 1, 2)));
153 * Sends a diagnostic message to the other side. This message can be sent at
154 * any time (but not while constructing another message). The message is
155 * printed immediately, but only if the client is being executed in verbose
156 * mode. These messages are primarily intended to ease debugging
157 * authentication problems. The total length of the message must not exceed
158 * 1024 bytes. This will automatically call packet_write_wait. If the
159 * remote side protocol flags do not indicate that it supports SSH_MSG_DEBUG,
160 * this will do nothing.
162 void packet_send_debug(const char *fmt,...) __attribute__((format(printf, 1, 2)));
164 /* Checks if there is any buffered output, and tries to write some of the output. */
165 void packet_write_poll(void);
167 /* Waits until all pending output data has been written. */
168 void packet_write_wait(void);
170 /* Returns true if there is buffered data to write to the connection. */
171 int packet_have_data_to_write(void);
173 /* Returns true if there is not too much data to write to the connection. */
174 int packet_not_very_much_data_to_write(void);
176 /* maximum packet size, requested by client with SSH_CMSG_MAX_PACKET_SIZE */
177 extern int max_packet_size;
178 int packet_set_maxsize(int s);
179 #define packet_get_maxsize() max_packet_size
181 /* Stores tty modes from the fd into current packet. */
182 void tty_make_modes(int fd);
184 /* Parses tty modes for the fd from the current packet. */
185 void tty_parse_modes(int fd, int *n_bytes_ptr);
187 #define packet_integrity_check(payload_len, expected_len, type) \
189 int _p = (payload_len), _e = (expected_len); \
191 log("Packet integrity error (%d != %d) at %s:%d", \
192 _p, _e, __FILE__, __LINE__); \
193 packet_disconnect("Packet integrity error. (%d)", (type)); \
197 #define packet_done() \
199 int _len = packet_remaining(); \
201 log("Packet integrity error (%d bytes remaining) at %s:%d", \
202 _len ,__FILE__, __LINE__); \
203 packet_disconnect("Packet integrity error."); \
207 /* remote host is connected via a socket/ipv4 */
208 int packet_connection_is_on_socket(void);
209 int packet_connection_is_ipv4(void);
211 /* enable SSH2 packet format */
212 void packet_set_ssh2_format(void);
214 /* returns remaining payload bytes */
215 int packet_remaining(void);
217 #endif /* PACKET_H */