1 /* 2 * 3 * packet.h 4 * 5 * Author: Tatu Ylonen <ylo@cs.hut.fi> 6 * 7 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 8 * All rights reserved 9 * 10 * Created: Sat Mar 18 02:02:14 1995 ylo 11 * 12 * Interface for the packet protocol functions. 13 * 14 * $FreeBSD$ 15 */ 16 17 /* RCSID("$Id: packet.h,v 1.15 2000/04/14 10:30:32 markus Exp $"); */ 18 19 #ifndef PACKET_H 20 #define PACKET_H 21 22 #include <openssl/bn.h> 23 24 /* 25 * Sets the socket used for communication. Disables encryption until 26 * packet_set_encryption_key is called. It is permissible that fd_in and 27 * fd_out are the same descriptor; in that case it is assumed to be a socket. 28 */ 29 void packet_set_connection(int fd_in, int fd_out); 30 31 /* Puts the connection file descriptors into non-blocking mode. */ 32 void packet_set_nonblocking(void); 33 34 /* Returns the file descriptor used for input. */ 35 int packet_get_connection_in(void); 36 37 /* Returns the file descriptor used for output. */ 38 int packet_get_connection_out(void); 39 40 /* 41 * Closes the connection (both descriptors) and clears and frees internal 42 * data structures. 43 */ 44 void packet_close(void); 45 46 /* 47 * Causes any further packets to be encrypted using the given key. The same 48 * key is used for both sending and reception. However, both directions are 49 * encrypted independently of each other. Cipher types are defined in ssh.h. 50 */ 51 void 52 packet_set_encryption_key(const unsigned char *key, unsigned int keylen, 53 int cipher_type); 54 55 /* 56 * Sets remote side protocol flags for the current connection. This can be 57 * called at any time. 58 */ 59 void packet_set_protocol_flags(unsigned int flags); 60 61 /* Returns the remote protocol flags set earlier by the above function. */ 62 unsigned int packet_get_protocol_flags(void); 63 64 /* Enables compression in both directions starting from the next packet. */ 65 void packet_start_compression(int level); 66 67 /* 68 * Informs that the current session is interactive. Sets IP flags for 69 * optimal performance in interactive use. 70 */ 71 void packet_set_interactive(int interactive, int keepalives); 72 73 /* Returns true if the current connection is interactive. */ 74 int packet_is_interactive(void); 75 76 /* Starts constructing a packet to send. */ 77 void packet_start(int type); 78 79 /* Appends a character to the packet data. */ 80 void packet_put_char(int ch); 81 82 /* Appends an integer to the packet data. */ 83 void packet_put_int(unsigned int value); 84 85 /* Appends an arbitrary precision integer to packet data. */ 86 void packet_put_bignum(BIGNUM * value); 87 void packet_put_bignum2(BIGNUM * value); 88 89 /* Appends a string to packet data. */ 90 void packet_put_string(const char *buf, unsigned int len); 91 void packet_put_cstring(const char *str); 92 void packet_put_raw(const char *buf, unsigned int len); 93 94 /* 95 * Finalizes and sends the packet. If the encryption key has been set, 96 * encrypts the packet before sending. 97 */ 98 void packet_send(void); 99 100 /* Waits until a packet has been received, and returns its type. */ 101 int packet_read(int *payload_len_ptr); 102 103 /* 104 * Waits until a packet has been received, verifies that its type matches 105 * that given, and gives a fatal error and exits if there is a mismatch. 106 */ 107 void packet_read_expect(int *payload_len_ptr, int type); 108 109 /* 110 * Checks if a full packet is available in the data received so far via 111 * packet_process_incoming. If so, reads the packet; otherwise returns 112 * SSH_MSG_NONE. This does not wait for data from the connection. 113 * SSH_MSG_DISCONNECT is handled specially here. Also, SSH_MSG_IGNORE 114 * messages are skipped by this function and are never returned to higher 115 * levels. 116 */ 117 int packet_read_poll(int *packet_len_ptr); 118 119 /* 120 * Buffers the given amount of input characters. This is intended to be used 121 * together with packet_read_poll. 122 */ 123 void packet_process_incoming(const char *buf, unsigned int len); 124 125 /* Returns a character (0-255) from the packet data. */ 126 unsigned int packet_get_char(void); 127 128 /* Returns an integer from the packet data. */ 129 unsigned int packet_get_int(void); 130 131 /* 132 * Returns an arbitrary precision integer from the packet data. The integer 133 * must have been initialized before this call. 134 */ 135 void packet_get_bignum(BIGNUM * value, int *length_ptr); 136 void packet_get_bignum2(BIGNUM * value, int *length_ptr); 137 char *packet_get_raw(int *length_ptr); 138 139 /* 140 * Returns a string from the packet data. The string is allocated using 141 * xmalloc; it is the responsibility of the calling program to free it when 142 * no longer needed. The length_ptr argument may be NULL, or point to an 143 * integer into which the length of the string is stored. 144 */ 145 char *packet_get_string(unsigned int *length_ptr); 146 147 /* 148 * Logs the error in syslog using LOG_INFO, constructs and sends a disconnect 149 * packet, closes the connection, and exits. This function never returns. 150 * The error message should not contain a newline. The total length of the 151 * message must not exceed 1024 bytes. 152 */ 153 void packet_disconnect(const char *fmt,...) __attribute__((format(printf, 1, 2))); 154 155 /* 156 * Sends a diagnostic message to the other side. This message can be sent at 157 * any time (but not while constructing another message). The message is 158 * printed immediately, but only if the client is being executed in verbose 159 * mode. These messages are primarily intended to ease debugging 160 * authentication problems. The total length of the message must not exceed 161 * 1024 bytes. This will automatically call packet_write_wait. If the 162 * remote side protocol flags do not indicate that it supports SSH_MSG_DEBUG, 163 * this will do nothing. 164 */ 165 void packet_send_debug(const char *fmt,...) __attribute__((format(printf, 1, 2))); 166 167 /* Checks if there is any buffered output, and tries to write some of the output. */ 168 void packet_write_poll(void); 169 170 /* Waits until all pending output data has been written. */ 171 void packet_write_wait(void); 172 173 /* Returns true if there is buffered data to write to the connection. */ 174 int packet_have_data_to_write(void); 175 176 /* Returns true if there is not too much data to write to the connection. */ 177 int packet_not_very_much_data_to_write(void); 178 179 /* maximum packet size, requested by client with SSH_CMSG_MAX_PACKET_SIZE */ 180 extern int max_packet_size; 181 int packet_set_maxsize(int s); 182 #define packet_get_maxsize() max_packet_size 183 184 /* Stores tty modes from the fd into current packet. */ 185 void tty_make_modes(int fd); 186 187 /* Parses tty modes for the fd from the current packet. */ 188 void tty_parse_modes(int fd, int *n_bytes_ptr); 189 190 #define packet_integrity_check(payload_len, expected_len, type) \ 191 do { \ 192 int _p = (payload_len), _e = (expected_len); \ 193 if (_p != _e) { \ 194 log("Packet integrity error (%d != %d) at %s:%d", \ 195 _p, _e, __FILE__, __LINE__); \ 196 packet_disconnect("Packet integrity error. (%d)", (type)); \ 197 } \ 198 } while (0) 199 200 #define packet_done() \ 201 do { \ 202 int _len = packet_remaining(); \ 203 if (_len > 0) { \ 204 log("Packet integrity error (%d bytes remaining) at %s:%d", \ 205 _len ,__FILE__, __LINE__); \ 206 packet_disconnect("Packet integrity error."); \ 207 } \ 208 } while (0) 209 210 /* remote host is connected via a socket/ipv4 */ 211 int packet_connection_is_on_socket(void); 212 int packet_connection_is_ipv4(void); 213 214 /* enable SSH2 packet format */ 215 void packet_set_ssh2_format(void); 216 217 /* returns remaining payload bytes */ 218 int packet_remaining(void); 219 220 #endif /* PACKET_H */ 221