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 1.24 2001/06/26 06:32:57 itojun 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, int);
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 *, u_int, int);
52 * Sets remote side protocol flags for the current connection. This can be
55 void packet_set_protocol_flags(u_int);
57 /* Returns the remote protocol flags set earlier by the above function. */
58 u_int packet_get_protocol_flags(void);
60 /* Enables compression in both directions starting from the next packet. */
61 void packet_start_compression(int);
64 * Informs that the current session is interactive. Sets IP flags for
65 * optimal performance in interactive use.
67 void packet_set_interactive(int);
69 /* Returns true if the current connection is interactive. */
70 int packet_is_interactive(void);
72 /* Starts constructing a packet to send. */
73 void packet_start(u_char);
75 /* Appends a character to the packet data. */
76 void packet_put_char(int ch);
78 /* Appends an integer to the packet data. */
79 void packet_put_int(u_int value);
81 /* Appends an arbitrary precision integer to packet data. */
82 void packet_put_bignum(BIGNUM * value);
83 void packet_put_bignum2(BIGNUM * value);
85 /* Appends a string to packet data. */
86 void packet_put_string(const char *buf, u_int len);
87 void packet_put_cstring(const char *str);
88 void packet_put_raw(const char *buf, u_int len);
91 * Finalizes and sends the packet. If the encryption key has been set,
92 * encrypts the packet before sending.
94 void packet_send(void);
96 /* Waits until a packet has been received, and returns its type. */
97 int packet_read(int *payload_len_ptr);
100 * Waits until a packet has been received, verifies that its type matches
101 * that given, and gives a fatal error and exits if there is a mismatch.
103 void packet_read_expect(int *payload_len_ptr, int type);
106 * Checks if a full packet is available in the data received so far via
107 * packet_process_incoming. If so, reads the packet; otherwise returns
108 * SSH_MSG_NONE. This does not wait for data from the connection.
109 * SSH_MSG_DISCONNECT is handled specially here. Also, SSH_MSG_IGNORE
110 * messages are skipped by this function and are never returned to higher
113 int packet_read_poll(int *packet_len_ptr);
116 * Buffers the given amount of input characters. This is intended to be used
117 * together with packet_read_poll.
119 void packet_process_incoming(const char *buf, u_int len);
121 /* Returns a character (0-255) from the packet data. */
122 u_int packet_get_char(void);
124 /* Returns an integer from the packet data. */
125 u_int packet_get_int(void);
128 * Returns an arbitrary precision integer from the packet data. The integer
129 * must have been initialized before this call.
131 void packet_get_bignum(BIGNUM * value, int *length_ptr);
132 void packet_get_bignum2(BIGNUM * value, int *length_ptr);
133 char *packet_get_raw(int *length_ptr);
136 * Returns a string from the packet data. The string is allocated using
137 * xmalloc; it is the responsibility of the calling program to free it when
138 * no longer needed. The length_ptr argument may be NULL, or point to an
139 * integer into which the length of the string is stored.
141 char *packet_get_string(u_int *length_ptr);
144 * Logs the error in syslog using LOG_INFO, constructs and sends a disconnect
145 * packet, closes the connection, and exits. This function never returns.
146 * The error message should not contain a newline. The total length of the
147 * message must not exceed 1024 bytes.
149 void packet_disconnect(const char *fmt,...) __attribute__((format(printf, 1, 2)));
152 * Sends a diagnostic message to the other side. This message can be sent at
153 * any time (but not while constructing another message). The message is
154 * printed immediately, but only if the client is being executed in verbose
155 * mode. These messages are primarily intended to ease debugging
156 * authentication problems. The total length of the message must not exceed
157 * 1024 bytes. This will automatically call packet_write_wait. If the
158 * remote side protocol flags do not indicate that it supports SSH_MSG_DEBUG,
159 * this will do nothing.
161 void packet_send_debug(const char *fmt,...) __attribute__((format(printf, 1, 2)));
163 /* Checks if there is any buffered output, and tries to write some of the output. */
164 void packet_write_poll(void);
166 /* Waits until all pending output data has been written. */
167 void packet_write_wait(void);
169 /* Returns true if there is buffered data to write to the connection. */
170 int packet_have_data_to_write(void);
172 /* Returns true if there is not too much data to write to the connection. */
173 int packet_not_very_much_data_to_write(void);
175 /* maximum packet size, requested by client with SSH_CMSG_MAX_PACKET_SIZE */
176 extern int max_packet_size;
177 int packet_set_maxsize(int);
178 #define packet_get_maxsize() max_packet_size
180 /* Stores tty modes from the fd or tiop into current packet. */
181 void tty_make_modes(int, struct termios *);
183 /* Parses tty modes for the fd from the current packet. */
184 void tty_parse_modes(int, int *);
186 #define packet_integrity_check(payload_len, expected_len, type) \
188 int _p = (payload_len), _e = (expected_len); \
190 log("Packet integrity error (%d != %d) at %s:%d", \
191 _p, _e, __FILE__, __LINE__); \
192 packet_disconnect("Packet integrity error. (%d)", (type)); \
196 #define packet_done() \
198 int _len = packet_remaining(); \
200 log("Packet integrity error (%d bytes remaining) at %s:%d", \
201 _len ,__FILE__, __LINE__); \
202 packet_disconnect("Packet integrity error."); \
206 /* remote host is connected via a socket/ipv4 */
207 int packet_connection_is_on_socket(void);
208 int packet_connection_is_ipv4(void);
210 /* returns remaining payload bytes */
211 int packet_remaining(void);
213 /* append an ignore message */
214 void packet_send_ignore(int);
216 /* add an ignore message and make sure size (current+ignore) = n*sumlen */
217 void packet_inject_ignore(int);
219 #endif /* PACKET_H */