[SSHD-1237] Don't warn about keep-alive channel requests

OpenSSH server sends keep-alive requests as channel requests if a
channel is open. Do not log a warning about such requests, simply
send back a failure reply. OpenSSH just expects any reply, whether
success or failure.

Author: tomaswolf

CHANGES.md

@@ -42,6 +42,9 @@
 * [PR-476](https://github.com/apache/mina-sshd/pull/476) Fix Android detection
 * [PR-486](https://github.com/apache/mina-sshd/pull/486) Add missing `equals` and `hashCode` to U2F key classes
 
+
+* [SSHD-1237](https://issues.apache.org/jira/browse/SSHD-1237) Don't warn about keep-alive channel requests
+
 ## New Features
 
 ## Behavioral changes and enhancements

sshd-core/src/main/java/org/apache/sshd/common/channel/AbstractChannel.java

@@ -337,8 +337,9 @@ protected void handleChannelRequest(String req, boolean wantReply, Buffer buffer
     protected void handleUnknownChannelRequest(String req, boolean wantReply, Buffer buffer) throws IOException {
         RequestHandler.Result r = handleInternalRequest(req, wantReply, buffer);
         if ((r == null) || RequestHandler.Result.Unsupported.equals(r)) {
-            log.warn("handleUnknownChannelRequest({}) Unknown channel request: {}[want-reply={}]", this, req,
-                    wantReply);
+            if (!req.startsWith("keepalive@") && !req.startsWith("keep-alive@")) {
+                log.warn("handleUnknownChannelRequest({}) Unknown channel request: {}[want-reply={}]", this, req, wantReply);
+            }
             sendResponse(buffer, req, RequestHandler.Result.Unsupported, wantReply);
         } else {
             sendResponse(buffer, req, r, wantReply);