[PATCH] server: Add a ssh_send_keepalive() function

[Nicolas Viennot <nicolas@xxxxxxxxxxx>]

Implementation of a ssh_send_keepalive() function.
Useful for keeping some client around as NATs may terminate connections.

Signed-off-by: Nicolas Viennot <nicolas@xxxxxxxxxxx>
---
 include/libssh/server.h |  2 ++
 src/server.c            | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/include/libssh/server.h b/include/libssh/server.h
index dbffecd..9d095fe 100644
--- a/include/libssh/server.h
+++ b/include/libssh/server.h
@@ -382,6 +382,8 @@ LIBSSH_API int ssh_channel_write_stderr(ssh_channel channel,
                                                 const void *data,
                                                 uint32_t len);

+LIBSSH_API int ssh_send_keepalive(ssh_session session);
+
 /* deprecated functions */
 SSH_DEPRECATED LIBSSH_API int ssh_accept(ssh_session session);
 SSH_DEPRECATED LIBSSH_API int channel_write_stderr(ssh_channel channel,
diff --git a/src/server.c b/src/server.c
index 0b62776..b31371f 100644
--- a/src/server.c
+++ b/src/server.c
@@ -1221,6 +1221,40 @@ int ssh_execute_message_callbacks(ssh_session session){
   return SSH_OK;
 }

+
+int ssh_send_keepalive(ssh_session session)
+{
+  struct ssh_string_struct *req;
+  int reply = 1;
+  int rc = SSH_ERROR;
+
+  req = ssh_string_from_char("keepalive@xxxxxxxxxxx");
+  if (req == NULL) {
+    ssh_set_error_oom(session);
+    goto out;
+  }
+
+  if (buffer_add_u8(session->out_buffer, SSH2_MSG_GLOBAL_REQUEST) < 0 ||
+      buffer_add_ssh_string(session->out_buffer, req) < 0 ||
+      buffer_add_u8(session->out_buffer, reply == 0 ? 0 : 1) < 0) {
+    ssh_set_error_oom(session);
+    goto out;
+  }
+
+  if (packet_send(session) == SSH_ERROR)
+    goto out;
+
+  ssh_handle_packets(session, 0);
+
+  SSH_LOG(SSH_LOG_PACKET, "Sent a keepalive");
+  rc = SSH_OK;
+
+out:
+  ssh_string_free(req);
+  return rc;
+}
+
 /** @} */

 /* vim: set ts=4 sw=4 et cindent: */
-- 
1.8.3.2