Add keep-alive support.

2025-11-20 02:42:09 +03:00 · 2010-02-25 15:58:52 +01:00
parent 69520e1564
commit 0d331aade1
5 changed files with 145 additions and 2 deletions
--- a/src/keepalive.c
+++ b/src/keepalive.c
@@ -0,0 +1,97 @@
+/* Copyright (C) 2010  Simon Josefsson
+ * Author: Simon Josefsson
+ *
+ * Redistribution and use in source and binary forms,
+ * with or without modification, are permitted provided
+ * that the following conditions are met:
+ *
+ *   Redistributions of source code must retain the above
+ *   copyright notice, this list of conditions and the
+ *   following disclaimer.
+ *
+ *   Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials
+ *   provided with the distribution.
+ *
+ *   Neither the name of the copyright holder nor the names
+ *   of any other contributors may be used to endorse or
+ *   promote products derived from this software without
+ *   specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
+ * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ */
+
+#include "libssh2_priv.h"
+#include "transport.h" /* _libssh2_transport_write */
+
+/* Keep-alive stuff. */
+
+LIBSSH2_API void
+libssh2_keepalive_config (LIBSSH2_SESSION *session,
+                          int want_reply,
+                          unsigned interval)
+{
+    if (interval == 1)
+        session->keepalive_interval = 2;
+    else
+        session->keepalive_interval = interval;
+    session->keepalive_want_reply = want_reply ? 1 : 0;
+}
+
+LIBSSH2_API int
+libssh2_keepalive_send (LIBSSH2_SESSION *session,
+                        int *seconds_to_next)
+{
+    time_t now;
+
+    if (!session->keepalive_interval) {
+        if (seconds_to_next)
+            *seconds_to_next = 0;
+        return 0;
+    }
+
+    now = time (NULL);
+
+    if (session->keepalive_last_sent + session->keepalive_interval <= now) {
+/* Format is "SSH_MSG_GLOBAL_REQUEST || 4-byte len || str || want-reply". */
+        unsigned char keepalive_data[]
+            = "\x50\x00\x00\x00\x15keepalive@libssh2.orgW";
+        size_t len = sizeof (keepalive_data) - 1;
+        int rc;
+
+        keepalive_data[len - 1] = session->keepalive_want_reply;
+
+        rc = _libssh2_transport_write(session, keepalive_data, len);
+/* Silently ignore PACKET_EAGAIN here: if the write buffer is
+   already full, sending another keepalive is not useful. */
+        if (rc && rc != PACKET_EAGAIN) {
+            libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND,
+                          "Unable to send keepalive message", 0);
+            return rc;
+        }
+
+        session->keepalive_last_sent = now;
+        if (seconds_to_next)
+            *seconds_to_next = session->keepalive_interval;
+    } else if (seconds_to_next) {
+        *seconds_to_next = session->keepalive_last_sent
+            + session->keepalive_interval - now;
+    }
+
+    return 0;
+}