5 * Author: Tatu Ylonen <ylo@cs.hut.fi>
7 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
10 * Created: Sat Mar 18 02:02:14 1995 ylo
12 * Interface for the packet protocol functions.
16 /* RCSID("$OpenBSD: packet.h,v 1.16 2000/06/20 01:39:43 markus Exp $"); */
21 #include <openssl/bn.h>
24 * Sets the socket used for communication. Disables encryption until
25 * packet_set_encryption_key is called. It is permissible that fd_in and
26 * fd_out are the same descriptor; in that case it is assumed to be a socket.
28 void packet_set_connection(int fd_in, int fd_out);
30 /* Puts the connection file descriptors into non-blocking mode. */
31 void packet_set_nonblocking(void);
33 /* Returns the file descriptor used for input. */
34 int packet_get_connection_in(void);
36 /* Returns the file descriptor used for output. */
37 int packet_get_connection_out(void);
40 * Closes the connection (both descriptors) and clears and frees internal
43 void packet_close(void);
46 * Causes any further packets to be encrypted using the given key. The same
47 * key is used for both sending and reception. However, both directions are
48 * encrypted independently of each other. Cipher types are defined in ssh.h.
51 packet_set_encryption_key(const unsigned char *key, unsigned int keylen,
55 * Sets remote side protocol flags for the current connection. This can be
58 void packet_set_protocol_flags(unsigned int flags);
60 /* Returns the remote protocol flags set earlier by the above function. */
61 unsigned int packet_get_protocol_flags(void);
63 /* Enables compression in both directions starting from the next packet. */
64 void packet_start_compression(int level);
67 * Informs that the current session is interactive. Sets IP flags for
68 * optimal performance in interactive use.
70 void packet_set_interactive(int interactive, int keepalives);
72 /* Returns true if the current connection is interactive. */
73 int packet_is_interactive(void);
75 /* Starts constructing a packet to send. */
76 void packet_start(int type);
78 /* Appends a character to the packet data. */
79 void packet_put_char(int ch);
81 /* Appends an integer to the packet data. */
82 void packet_put_int(unsigned int value);
84 /* Appends an arbitrary precision integer to packet data. */
85 void packet_put_bignum(BIGNUM * value);
86 void packet_put_bignum2(BIGNUM * value);
88 /* Appends a string to packet data. */
89 void packet_put_string(const char *buf, unsigned int len);
90 void packet_put_cstring(const char *str);
91 void packet_put_raw(const char *buf, unsigned int len);
94 * Finalizes and sends the packet. If the encryption key has been set,
95 * encrypts the packet before sending.
97 void packet_send(void);
99 /* Waits until a packet has been received, and returns its type. */
100 int packet_read(int *payload_len_ptr);
103 * Waits until a packet has been received, verifies that its type matches
104 * that given, and gives a fatal error and exits if there is a mismatch.
106 void packet_read_expect(int *payload_len_ptr, int type);
109 * Checks if a full packet is available in the data received so far via
110 * packet_process_incoming. If so, reads the packet; otherwise returns
111 * SSH_MSG_NONE. This does not wait for data from the connection.
112 * SSH_MSG_DISCONNECT is handled specially here. Also, SSH_MSG_IGNORE
113 * messages are skipped by this function and are never returned to higher
116 int packet_read_poll(int *packet_len_ptr);
119 * Buffers the given amount of input characters. This is intended to be used
120 * together with packet_read_poll.
122 void packet_process_incoming(const char *buf, unsigned int len);
124 /* Returns a character (0-255) from the packet data. */
125 unsigned int packet_get_char(void);
127 /* Returns an integer from the packet data. */
128 unsigned int packet_get_int(void);
131 * Returns an arbitrary precision integer from the packet data. The integer
132 * must have been initialized before this call.
134 void packet_get_bignum(BIGNUM * value, int *length_ptr);
135 void packet_get_bignum2(BIGNUM * value, int *length_ptr);
136 char *packet_get_raw(int *length_ptr);
139 * Returns a string from the packet data. The string is allocated using
140 * xmalloc; it is the responsibility of the calling program to free it when
141 * no longer needed. The length_ptr argument may be NULL, or point to an
142 * integer into which the length of the string is stored.
144 char *packet_get_string(unsigned int *length_ptr);
147 * Logs the error in syslog using LOG_INFO, constructs and sends a disconnect
148 * packet, closes the connection, and exits. This function never returns.
149 * The error message should not contain a newline. The total length of the
150 * message must not exceed 1024 bytes.
152 void packet_disconnect(const char *fmt,...) __attribute__((format(printf, 1, 2)));
155 * Sends a diagnostic message to the other side. This message can be sent at
156 * any time (but not while constructing another message). The message is
157 * printed immediately, but only if the client is being executed in verbose
158 * mode. These messages are primarily intended to ease debugging
159 * authentication problems. The total length of the message must not exceed
160 * 1024 bytes. This will automatically call packet_write_wait. If the
161 * remote side protocol flags do not indicate that it supports SSH_MSG_DEBUG,
162 * this will do nothing.
164 void packet_send_debug(const char *fmt,...) __attribute__((format(printf, 1, 2)));
166 /* Checks if there is any buffered output, and tries to write some of the output. */
167 void packet_write_poll(void);
169 /* Waits until all pending output data has been written. */
170 void packet_write_wait(void);
172 /* Returns true if there is buffered data to write to the connection. */
173 int packet_have_data_to_write(void);
175 /* Returns true if there is not too much data to write to the connection. */
176 int packet_not_very_much_data_to_write(void);
178 /* maximum packet size, requested by client with SSH_CMSG_MAX_PACKET_SIZE */
179 extern int max_packet_size;
180 int packet_set_maxsize(int s);
181 #define packet_get_maxsize() max_packet_size
183 /* Stores tty modes from the fd into current packet. */
184 void tty_make_modes(int fd);
186 /* Parses tty modes for the fd from the current packet. */
187 void tty_parse_modes(int fd, int *n_bytes_ptr);
189 #define packet_integrity_check(payload_len, expected_len, type) \
191 int _p = (payload_len), _e = (expected_len); \
193 log("Packet integrity error (%d != %d) at %s:%d", \
194 _p, _e, __FILE__, __LINE__); \
195 packet_disconnect("Packet integrity error. (%d)", (type)); \
199 #define packet_done() \
201 int _len = packet_remaining(); \
203 log("Packet integrity error (%d bytes remaining) at %s:%d", \
204 _len ,__FILE__, __LINE__); \
205 packet_disconnect("Packet integrity error."); \
209 /* remote host is connected via a socket/ipv4 */
210 int packet_connection_is_on_socket(void);
211 int packet_connection_is_ipv4(void);
213 /* enable SSH2 packet format */
214 void packet_set_ssh2_format(void);
216 /* returns remaining payload bytes */
217 int packet_remaining(void);
219 #endif /* PACKET_H */