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.
22 #include <openssl/bn.h>
29 * Sets the socket used for communication. Disables encryption until
30 * packet_set_encryption_key is called. It is permissible that fd_in and
31 * fd_out are the same descriptor; in that case it is assumed to be a socket.
33 void packet_set_connection(int fd_in, int fd_out);
35 /* Puts the connection file descriptors into non-blocking mode. */
36 void packet_set_nonblocking(void);
38 /* Returns the file descriptor used for input. */
39 int packet_get_connection_in(void);
41 /* Returns the file descriptor used for output. */
42 int packet_get_connection_out(void);
45 * Closes the connection (both descriptors) and clears and frees internal
48 void packet_close(void);
51 * Causes any further packets to be encrypted using the given key. The same
52 * key is used for both sending and reception. However, both directions are
53 * encrypted independently of each other. Cipher types are defined in ssh.h.
56 packet_set_encryption_key(const unsigned char *key, unsigned int keylen,
60 * Sets remote side protocol flags for the current connection. This can be
63 void packet_set_protocol_flags(unsigned int flags);
65 /* Returns the remote protocol flags set earlier by the above function. */
66 unsigned int packet_get_protocol_flags(void);
68 /* Enables compression in both directions starting from the next packet. */
69 void packet_start_compression(int level);
72 * Informs that the current session is interactive. Sets IP flags for
73 * optimal performance in interactive use.
75 void packet_set_interactive(int interactive, int keepalives);
77 /* Returns true if the current connection is interactive. */
78 int packet_is_interactive(void);
80 /* Starts constructing a packet to send. */
81 void packet_start(int type);
83 /* Appends a character to the packet data. */
84 void packet_put_char(int ch);
86 /* Appends an integer to the packet data. */
87 void packet_put_int(unsigned int value);
89 /* Appends an arbitrary precision integer to packet data. */
90 void packet_put_bignum(BIGNUM * value);
91 void packet_put_bignum2(BIGNUM * value);
93 /* Appends a string to packet data. */
94 void packet_put_string(const char *buf, unsigned int len);
95 void packet_put_cstring(const char *str);
96 void packet_put_raw(const char *buf, unsigned int len);
99 * Finalizes and sends the packet. If the encryption key has been set,
100 * encrypts the packet before sending.
102 void packet_send(void);
104 /* Waits until a packet has been received, and returns its type. */
105 int packet_read(int *payload_len_ptr);
108 * Waits until a packet has been received, verifies that its type matches
109 * that given, and gives a fatal error and exits if there is a mismatch.
111 void packet_read_expect(int *payload_len_ptr, int type);
114 * Checks if a full packet is available in the data received so far via
115 * packet_process_incoming. If so, reads the packet; otherwise returns
116 * SSH_MSG_NONE. This does not wait for data from the connection.
117 * SSH_MSG_DISCONNECT is handled specially here. Also, SSH_MSG_IGNORE
118 * messages are skipped by this function and are never returned to higher
121 int packet_read_poll(int *packet_len_ptr);
124 * Buffers the given amount of input characters. This is intended to be used
125 * together with packet_read_poll.
127 void packet_process_incoming(const char *buf, unsigned int len);
129 /* Returns a character (0-255) from the packet data. */
130 unsigned int packet_get_char(void);
132 /* Returns an integer from the packet data. */
133 unsigned int packet_get_int(void);
136 * Returns an arbitrary precision integer from the packet data. The integer
137 * must have been initialized before this call.
139 void packet_get_bignum(BIGNUM * value, int *length_ptr);
140 void packet_get_bignum2(BIGNUM * value, int *length_ptr);
141 char *packet_get_raw(int *length_ptr);
144 * Returns a string from the packet data. The string is allocated using
145 * xmalloc; it is the responsibility of the calling program to free it when
146 * no longer needed. The length_ptr argument may be NULL, or point to an
147 * integer into which the length of the string is stored.
149 char *packet_get_string(unsigned int *length_ptr);
152 * Logs the error in syslog using LOG_INFO, constructs and sends a disconnect
153 * packet, closes the connection, and exits. This function never returns.
154 * The error message should not contain a newline. The total length of the
155 * message must not exceed 1024 bytes.
157 void packet_disconnect(const char *fmt,...) __attribute__((format(printf, 1, 2)));
160 * Sends a diagnostic message to the other side. This message can be sent at
161 * any time (but not while constructing another message). The message is
162 * printed immediately, but only if the client is being executed in verbose
163 * mode. These messages are primarily intended to ease debugging
164 * authentication problems. The total length of the message must not exceed
165 * 1024 bytes. This will automatically call packet_write_wait. If the
166 * remote side protocol flags do not indicate that it supports SSH_MSG_DEBUG,
167 * this will do nothing.
169 void packet_send_debug(const char *fmt,...) __attribute__((format(printf, 1, 2)));
171 /* Checks if there is any buffered output, and tries to write some of the output. */
172 void packet_write_poll(void);
174 /* Waits until all pending output data has been written. */
175 void packet_write_wait(void);
177 /* Returns true if there is buffered data to write to the connection. */
178 int packet_have_data_to_write(void);
180 /* Returns true if there is not too much data to write to the connection. */
181 int packet_not_very_much_data_to_write(void);
183 /* maximum packet size, requested by client with SSH_CMSG_MAX_PACKET_SIZE */
184 extern int max_packet_size;
185 int packet_set_maxsize(int s);
186 #define packet_get_maxsize() max_packet_size
188 /* Stores tty modes from the fd into current packet. */
189 void tty_make_modes(int fd);
191 /* Parses tty modes for the fd from the current packet. */
192 void tty_parse_modes(int fd, int *n_bytes_ptr);
194 #define packet_integrity_check(payload_len, expected_len, type) \
196 int _p = (payload_len), _e = (expected_len); \
198 log("Packet integrity error (%d != %d) at %s:%d", \
199 _p, _e, __FILE__, __LINE__); \
200 packet_disconnect("Packet integrity error. (%d)", (type)); \
204 #define packet_done() \
206 int _len = packet_remaining(); \
208 log("Packet integrity error (%d bytes remaining) at %s:%d", \
209 _len ,__FILE__, __LINE__); \
210 packet_disconnect("Packet integrity error."); \
214 /* remote host is connected via a socket/ipv4 */
215 int packet_connection_is_on_socket(void);
216 int packet_connection_is_ipv4(void);
218 /* enable SSH2 packet format */
219 void packet_set_ssh2_format(void);
221 /* returns remaining payload bytes */
222 int packet_remaining(void);
224 #endif /* PACKET_H */