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.
24 #include <openssl/bn.h>
31 * Sets the socket used for communication. Disables encryption until
32 * packet_set_encryption_key is called. It is permissible that fd_in and
33 * fd_out are the same descriptor; in that case it is assumed to be a socket.
35 void packet_set_connection(int fd_in, int fd_out);
37 /* Puts the connection file descriptors into non-blocking mode. */
38 void packet_set_nonblocking(void);
40 /* Returns the file descriptor used for input. */
41 int packet_get_connection_in(void);
43 /* Returns the file descriptor used for output. */
44 int packet_get_connection_out(void);
47 * Closes the connection (both descriptors) and clears and frees internal
50 void packet_close(void);
53 * Causes any further packets to be encrypted using the given key. The same
54 * key is used for both sending and reception. However, both directions are
55 * encrypted independently of each other. Cipher types are defined in ssh.h.
58 packet_set_encryption_key(const unsigned char *key, unsigned int keylen,
62 * Sets remote side protocol flags for the current connection. This can be
65 void packet_set_protocol_flags(unsigned int flags);
67 /* Returns the remote protocol flags set earlier by the above function. */
68 unsigned int packet_get_protocol_flags(void);
70 /* Enables compression in both directions starting from the next packet. */
71 void packet_start_compression(int level);
74 * Informs that the current session is interactive. Sets IP flags for
75 * optimal performance in interactive use.
77 void packet_set_interactive(int interactive, int keepalives);
79 /* Returns true if the current connection is interactive. */
80 int packet_is_interactive(void);
82 /* Starts constructing a packet to send. */
83 void packet_start(int type);
85 /* Appends a character to the packet data. */
86 void packet_put_char(int ch);
88 /* Appends an integer to the packet data. */
89 void packet_put_int(unsigned int value);
91 /* Appends an arbitrary precision integer to packet data. */
92 void packet_put_bignum(BIGNUM * value);
94 /* Appends a string to packet data. */
95 void packet_put_string(const char *buf, unsigned int len);
98 * Finalizes and sends the packet. If the encryption key has been set,
99 * encrypts the packet before sending.
101 void packet_send(void);
103 /* Waits until a packet has been received, and returns its type. */
104 int packet_read(int *payload_len_ptr);
107 * Waits until a packet has been received, verifies that its type matches
108 * that given, and gives a fatal error and exits if there is a mismatch.
110 void packet_read_expect(int *payload_len_ptr, int type);
113 * Checks if a full packet is available in the data received so far via
114 * packet_process_incoming. If so, reads the packet; otherwise returns
115 * SSH_MSG_NONE. This does not wait for data from the connection.
116 * SSH_MSG_DISCONNECT is handled specially here. Also, SSH_MSG_IGNORE
117 * messages are skipped by this function and are never returned to higher
120 int packet_read_poll(int *packet_len_ptr);
123 * Buffers the given amount of input characters. This is intended to be used
124 * together with packet_read_poll.
126 void packet_process_incoming(const char *buf, unsigned int len);
128 /* Returns a character (0-255) from the packet data. */
129 unsigned int packet_get_char(void);
131 /* Returns an integer from the packet data. */
132 unsigned int packet_get_int(void);
135 * Returns an arbitrary precision integer from the packet data. The integer
136 * must have been initialized before this call.
138 void packet_get_bignum(BIGNUM * value, int *length_ptr);
141 * Returns a string from the packet data. The string is allocated using
142 * xmalloc; it is the responsibility of the calling program to free it when
143 * no longer needed. The length_ptr argument may be NULL, or point to an
144 * integer into which the length of the string is stored.
146 char *packet_get_string(unsigned int *length_ptr);
149 * Logs the error in syslog using LOG_INFO, constructs and sends a disconnect
150 * packet, closes the connection, and exits. This function never returns.
151 * The error message should not contain a newline. The total length of the
152 * message must not exceed 1024 bytes.
154 void packet_disconnect(const char *fmt,...);
157 * Sends a diagnostic message to the other side. This message can be sent at
158 * any time (but not while constructing another message). The message is
159 * printed immediately, but only if the client is being executed in verbose
160 * mode. These messages are primarily intended to ease debugging
161 * authentication problems. The total length of the message must not exceed
162 * 1024 bytes. This will automatically call packet_write_wait. If the
163 * remote side protocol flags do not indicate that it supports SSH_MSG_DEBUG,
164 * this will do nothing.
166 void packet_send_debug(const char *fmt,...);
168 /* Checks if there is any buffered output, and tries to write some of the output. */
169 void packet_write_poll(void);
171 /* Waits until all pending output data has been written. */
172 void packet_write_wait(void);
174 /* Returns true if there is buffered data to write to the connection. */
175 int packet_have_data_to_write(void);
177 /* Returns true if there is not too much data to write to the connection. */
178 int packet_not_very_much_data_to_write(void);
180 /* maximum packet size, requested by client with SSH_CMSG_MAX_PACKET_SIZE */
181 extern int max_packet_size;
182 int packet_set_maxsize(int s);
183 #define packet_get_maxsize() max_packet_size
185 /* Stores tty modes from the fd into current packet. */
186 void tty_make_modes(int fd);
188 /* Parses tty modes for the fd from the current packet. */
189 void tty_parse_modes(int fd, int *n_bytes_ptr);
191 #define packet_integrity_check(payload_len, expected_len, type) \
193 int _p = (payload_len), _e = (expected_len); \
195 log("Packet integrity error (%d != %d) at %s:%d", \
196 _p, _e, __FILE__, __LINE__); \
197 packet_disconnect("Packet integrity error. (%d)", (type)); \
201 #endif /* PACKET_H */