1 /* Copyright (C) 2010 Simon Josefsson
2 * Author: Simon Josefsson
3 *
4 * Redistribution and use in source and binary forms,
5 * with or without modification, are permitted provided
6 * that the following conditions are met:
7 *
8 * Redistributions of source code must retain the above
9 * copyright notice, this list of conditions and the
10 * following disclaimer.
11 *
12 * Redistributions in binary form must reproduce the above
13 * copyright notice, this list of conditions and the following
14 * disclaimer in the documentation and/or other materials
15 * provided with the distribution.
16 *
17 * Neither the name of the copyright holder nor the names
18 * of any other contributors may be used to endorse or
19 * promote products derived from this software without
20 * specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
23 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
24 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
27 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
29 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
30 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
32 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
33 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
34 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
35 * OF SUCH DAMAGE.
36 *
37 */
38
39 #include "libssh2_priv.h"
40 #include "transport.h" /* _libssh2_transport_write */
41
42 /* Keep-alive stuff. */
43
44 LIBSSH2_API void
libssh2_keepalive_config(LIBSSH2_SESSION * session,int want_reply,unsigned interval)45 libssh2_keepalive_config (LIBSSH2_SESSION *session,
46 int want_reply,
47 unsigned interval)
48 {
49 if(interval == 1)
50 session->keepalive_interval = 2;
51 else
52 session->keepalive_interval = interval;
53 session->keepalive_want_reply = want_reply ? 1 : 0;
54 }
55
56 LIBSSH2_API int
libssh2_keepalive_send(LIBSSH2_SESSION * session,int * seconds_to_next)57 libssh2_keepalive_send (LIBSSH2_SESSION *session,
58 int *seconds_to_next)
59 {
60 time_t now;
61
62 if(!session->keepalive_interval) {
63 if(seconds_to_next)
64 *seconds_to_next = 0;
65 return 0;
66 }
67
68 now = time(NULL);
69
70 if(session->keepalive_last_sent + session->keepalive_interval <= now) {
71 /* Format is
72 "SSH_MSG_GLOBAL_REQUEST || 4-byte len || str || want-reply". */
73 unsigned char keepalive_data[]
74 = "\x50\x00\x00\x00\x15keepalive@libssh2.orgW";
75 size_t len = sizeof(keepalive_data) - 1;
76 int rc;
77
78 keepalive_data[len - 1] =
79 (unsigned char)session->keepalive_want_reply;
80
81 rc = _libssh2_transport_send(session, keepalive_data, len, NULL, 0);
82 /* Silently ignore PACKET_EAGAIN here: if the write buffer is
83 already full, sending another keepalive is not useful. */
84 if(rc && rc != LIBSSH2_ERROR_EAGAIN) {
85 _libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND,
86 "Unable to send keepalive message");
87 return rc;
88 }
89
90 session->keepalive_last_sent = now;
91 if(seconds_to_next)
92 *seconds_to_next = session->keepalive_interval;
93 }
94 else if(seconds_to_next) {
95 *seconds_to_next = (int) (session->keepalive_last_sent - now)
96 + session->keepalive_interval;
97 }
98
99 return 0;
100 }
101