libssh  0.7.3
session.h
1 /*
2  * This file is part of the SSH Library
3  *
4  * Copyright (c) 2009 by Aris Adamantiadis
5  *
6  * This library is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * This library is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with this library; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #ifndef SESSION_H_
22 #define SESSION_H_
23 #include <stdbool.h>
24 #include "libssh/priv.h"
25 #include "libssh/kex.h"
26 #include "libssh/packet.h"
27 #include "libssh/pcap.h"
28 #include "libssh/auth.h"
29 #include "libssh/channels.h"
30 #include "libssh/poll.h"
31 
32 /* These are the different states a SSH session can be into its life */
33 enum ssh_session_state_e {
34  SSH_SESSION_STATE_NONE=0,
35  SSH_SESSION_STATE_CONNECTING,
36  SSH_SESSION_STATE_SOCKET_CONNECTED,
37  SSH_SESSION_STATE_BANNER_RECEIVED,
38  SSH_SESSION_STATE_INITIAL_KEX,
39  SSH_SESSION_STATE_KEXINIT_RECEIVED,
40  SSH_SESSION_STATE_DH,
41  SSH_SESSION_STATE_AUTHENTICATING,
42  SSH_SESSION_STATE_AUTHENTICATED,
43  SSH_SESSION_STATE_ERROR,
44  SSH_SESSION_STATE_DISCONNECTED
45 };
46 
47 enum ssh_dh_state_e {
48  DH_STATE_INIT=0,
49  DH_STATE_INIT_SENT,
50  DH_STATE_NEWKEYS_SENT,
51  DH_STATE_FINISHED
52 };
53 
54 enum ssh_pending_call_e {
55  SSH_PENDING_CALL_NONE = 0,
56  SSH_PENDING_CALL_CONNECT,
57  SSH_PENDING_CALL_AUTH_NONE,
58  SSH_PENDING_CALL_AUTH_PASSWORD,
59  SSH_PENDING_CALL_AUTH_OFFER_PUBKEY,
60  SSH_PENDING_CALL_AUTH_PUBKEY,
61  SSH_PENDING_CALL_AUTH_AGENT,
62  SSH_PENDING_CALL_AUTH_KBDINT_INIT,
63  SSH_PENDING_CALL_AUTH_KBDINT_SEND,
64  SSH_PENDING_CALL_AUTH_GSSAPI_MIC
65 };
66 
67 /* libssh calls may block an undefined amount of time */
68 #define SSH_SESSION_FLAG_BLOCKING 1
69 
70 /* Client successfully authenticated */
71 #define SSH_SESSION_FLAG_AUTHENTICATED 2
72 
73 /* The KEXINIT message can be sent first by either of the parties so this flag
74  * indicates that the message was already sent to make sure it is sent and avoid
75  * sending it twice during key exchange to simplify the state machine. */
76 #define SSH_SESSION_FLAG_KEXINIT_SENT 4
77 
78 /* codes to use with ssh_handle_packets*() */
79 /* Infinite timeout */
80 #define SSH_TIMEOUT_INFINITE -1
81 /* Use the timeout defined by user if any. Mostly used with new connections */
82 #define SSH_TIMEOUT_USER -2
83 /* Use the default timeout, depending on ssh_is_blocking() */
84 #define SSH_TIMEOUT_DEFAULT -3
85 /* Don't block at all */
86 #define SSH_TIMEOUT_NONBLOCKING 0
87 
88 /* members that are common to ssh_session and ssh_bind */
89 struct ssh_common_struct {
90  struct error_struct error;
91  ssh_callbacks callbacks; /* Callbacks to user functions */
92  int log_verbosity; /* verbosity of the log functions */
93 };
94 
95 struct ssh_session_struct {
96  struct ssh_common_struct common;
97  struct ssh_socket_struct *socket;
98  char *serverbanner;
99  char *clientbanner;
100  int protoversion;
101  int server;
102  int client;
103  int openssh;
104  uint32_t send_seq;
105  uint32_t recv_seq;
106 
107  int connected;
108  /* !=0 when the user got a session handle */
109  int alive;
110  /* two previous are deprecated */
111  /* int auth_service_asked; */
112 
113  /* session flags (SSH_SESSION_FLAG_*) */
114  int flags;
115 
116  ssh_string banner; /* that's the issue banner from
117  the server */
118  char *discon_msg; /* disconnect message from
119  the remote host */
120  ssh_buffer in_buffer;
121  PACKET in_packet;
122  ssh_buffer out_buffer;
123 
124  /* the states are used by the nonblocking stuff to remember */
125  /* where it was before being interrupted */
126  enum ssh_pending_call_e pending_call_state;
127  enum ssh_session_state_e session_state;
128  int packet_state;
129  enum ssh_dh_state_e dh_handshake_state;
130  enum ssh_auth_service_state_e auth_service_state;
131  enum ssh_auth_state_e auth_state;
132  enum ssh_channel_request_state_e global_req_state;
133  struct ssh_agent_state_struct *agent_state;
134  struct ssh_auth_auto_state_struct *auth_auto_state;
135 
136  /* Sending this flag before key exchange to save one round trip during the
137  * key exchange. This might make sense on high-latency connections.
138  * So far internal only for testing. Usable only on the client side --
139  * there is no key exchange method that would start with server message */
140  bool send_first_kex_follows;
141  /*
142  * RFC 4253, 7.1: if the first_kex_packet_follows flag was set in
143  * the received SSH_MSG_KEXINIT, but the guess was wrong, this
144  * field will be set such that the following guessed packet will
145  * be ignored on the receiving side. Once that packet has been received and
146  * ignored, this field is cleared.
147  * On the sending side, this is set after we got peer KEXINIT message and we
148  * need to resend the initial message of the negotiated KEX algorithm.
149  */
150  bool first_kex_follows_guess_wrong;
151 
152  ssh_buffer in_hashbuf;
153  ssh_buffer out_hashbuf;
154  struct ssh_crypto_struct *current_crypto;
155  struct ssh_crypto_struct *next_crypto; /* next_crypto is going to be used after a SSH2_MSG_NEWKEYS */
156 
157  struct ssh_list *channels; /* linked list of channels */
158  int maxchannel;
159  int exec_channel_opened; /* version 1 only. more
160  info in channels1.c */
161  ssh_agent agent; /* ssh agent */
162 
163 /* keyb interactive data */
164  struct ssh_kbdint_struct *kbdint;
165  struct ssh_gssapi_struct *gssapi;
166  int version; /* 1 or 2 */
167  /* server host keys */
168  struct {
169  ssh_key rsa_key;
170  ssh_key dsa_key;
171  ssh_key ecdsa_key;
172  ssh_key ed25519_key;
173  /* The type of host key wanted by client */
174  enum ssh_keytypes_e hostkey;
175  } srv;
176  /* auths accepted by server */
177  int auth_methods;
178  struct ssh_list *ssh_message_list; /* list of delayed SSH messages */
179  int (*ssh_message_callback)( struct ssh_session_struct *session, ssh_message msg, void *userdata);
180  void *ssh_message_callback_data;
181  ssh_server_callbacks server_callbacks;
182  void (*ssh_connection_callback)( struct ssh_session_struct *session);
183  struct ssh_packet_callbacks_struct default_packet_callbacks;
184  struct ssh_list *packet_callbacks;
185  struct ssh_socket_callbacks_struct socket_callbacks;
186  ssh_poll_ctx default_poll_ctx;
187  /* options */
188 #ifdef WITH_PCAP
189  ssh_pcap_context pcap_ctx; /* pcap debugging context */
190 #endif
191  struct {
192  struct ssh_list *identity;
193  char *username;
194  char *host;
195  char *bindaddr; /* bind the client to an ip addr */
196  char *sshdir;
197  char *knownhosts;
198  char *wanted_methods[10];
199  char *ProxyCommand;
200  char *custombanner;
201  unsigned long timeout; /* seconds */
202  unsigned long timeout_usec;
203  unsigned int port;
204  socket_t fd;
205  int StrictHostKeyChecking;
206  int ssh2;
207  int ssh1;
208  char compressionlevel;
209  char *gss_server_identity;
210  char *gss_client_identity;
211  int gss_delegate_creds;
212  } opts;
213  /* counters */
214  ssh_counter socket_counter;
215  ssh_counter raw_counter;
216 };
217 
223 typedef int (*ssh_termination_function)(void *user);
224 int ssh_handle_packets(ssh_session session, int timeout);
225 int ssh_handle_packets_termination(ssh_session session, int timeout,
226  ssh_termination_function fct, void *user);
227 void ssh_socket_exception_callback(int code, int errno_code, void *user);
228 
229 #endif /* SESSION_H_ */
These are the callbacks exported by the socket structure They are called by the socket module when a ...
Definition: callbacks.h:363