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.
23 #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
31 and fd_out are the same descriptor; in that case it is assumed to
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);
44 /* Closes the connection (both descriptors) and clears and frees
45 internal data structures. */
46 void packet_close(void);
48 /* Causes any further packets to be encrypted using the given key. The same
49 key is used for both sending and reception. However, both directions
50 are encrypted independently of each other. Cipher types are
52 void packet_set_encryption_key(const unsigned char *key, unsigned int keylen,
53 int cipher_type, int is_client);
55 /* Sets remote side protocol flags for the current connection. This can
56 be called at any time. */
57 void packet_set_protocol_flags(unsigned int flags);
59 /* Returns the remote protocol flags set earlier by the above function. */
60 unsigned int packet_get_protocol_flags(void);
62 /* Enables compression in both directions starting from the next packet. */
63 void packet_start_compression(int level);
65 /* Informs that the current session is interactive. Sets IP flags for optimal
66 performance in interactive use. */
67 void packet_set_interactive(int interactive, int keepalives);
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(int type);
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(unsigned int value);
81 /* Appends an arbitrary precision integer to packet data. */
82 void packet_put_bignum(BIGNUM *value);
84 /* Appends a string to packet data. */
85 void packet_put_string(const char *buf, unsigned int len);
87 /* Finalizes and sends the packet. If the encryption key has been set,
88 encrypts the packet before sending. */
89 void packet_send(void);
91 /* Waits until a packet has been received, and returns its type. */
92 int packet_read(int *payload_len_ptr);
94 /* Waits until a packet has been received, verifies that its type matches
95 that given, and gives a fatal error and exits if there is a mismatch. */
96 void packet_read_expect(int *payload_len_ptr, int type);
98 /* Checks if a full packet is available in the data received so far via
99 packet_process_incoming. If so, reads the packet; otherwise returns
100 SSH_MSG_NONE. This does not wait for data from the connection.
102 SSH_MSG_DISCONNECT is handled specially here. Also,
103 SSH_MSG_IGNORE messages are skipped by this function and are never returned
105 int packet_read_poll(int *packet_len_ptr);
107 /* Buffers the given amount of input characters. This is intended to be
108 used together with packet_read_poll. */
109 void packet_process_incoming(const char *buf, unsigned int len);
111 /* Returns a character (0-255) from the packet data. */
112 unsigned int packet_get_char(void);
114 /* Returns an integer from the packet data. */
115 unsigned int packet_get_int(void);
117 /* Returns an arbitrary precision integer from the packet data. The integer
118 must have been initialized before this call. */
119 void packet_get_bignum(BIGNUM *value, int *length_ptr);
121 /* Returns a string from the packet data. The string is allocated using
122 xmalloc; it is the responsibility of the calling program to free it when
123 no longer needed. The length_ptr argument may be NULL, or point to an
124 integer into which the length of the string is stored. */
125 char *packet_get_string(unsigned int *length_ptr);
127 /* Logs the error in syslog using LOG_INFO, constructs and sends a disconnect
128 packet, closes the connection, and exits. This function never returns.
129 The error message should not contain a newline. The total length of the
130 message must not exceed 1024 bytes. */
131 void packet_disconnect(const char *fmt, ...);
133 /* Sends a diagnostic message to the other side. This message
134 can be sent at any time (but not while constructing another message).
135 The message is printed immediately, but only if the client is being
136 executed in verbose mode. These messages are primarily intended to
137 ease debugging authentication problems. The total length of the message
138 must not exceed 1024 bytes. This will automatically call
139 packet_write_wait. If the remote side protocol flags do not indicate
140 that it supports SSH_MSG_DEBUG, this will do nothing. */
141 void packet_send_debug(const char *fmt, ...);
143 /* Checks if there is any buffered output, and tries to write some of the
145 void packet_write_poll(void);
147 /* Waits until all pending output data has been written. */
148 void packet_write_wait(void);
150 /* Returns true if there is buffered data to write to the connection. */
151 int packet_have_data_to_write(void);
153 /* Returns true if there is not too much data to write to the connection. */
154 int packet_not_very_much_data_to_write(void);
156 /* Stores tty modes from the fd into current packet. */
157 void tty_make_modes(int fd);
159 /* Parses tty modes for the fd from the current packet. */
160 void tty_parse_modes(int fd, int *n_bytes_ptr);
162 #define packet_integrity_check(payload_len, expected_len, type) \
164 int _p = (payload_len), _e = (expected_len); \
166 log("Packet integrity error (%d != %d) at %s:%d", \
167 _p, _e, __FILE__, __LINE__); \
168 packet_disconnect("Packet integrity error. (%d)", (type)); \
172 #endif /* PACKET_H */