NETCONF Incorrect Client Hello Response

[kennedyjd]

Hello,
In src\Renci.SshNet\Netconf\NetConfSession.cs, lines 41 - 42 is missing the client request for the 1.1 protocol. The code should read:

            ClientCapabilities.LoadXml("<?xml version=\"1.0\" encoding=\"UTF-8\"?>" +
                                                "<hello xmlns=\"urn:ietf:params:xml:ns:netconf:base:1.0\">" +
                                                    "<capabilities>" +
                                                        "<capability>" +
                                                            "urn:ietf:params:netconf:base:1.0" +
                                                        "</capability>" +
                                                        "<capability>" +
                                                            "urn:ietf:params:netconf:base:1.1" +
                                                        "</capability>" +
                                                    "</capabilities>" +
                                                "</hello>");

Without adding the second capability, line 134 is invalid:

            _usingFramingProtocol = (ServerCapabilities.SelectSingleNode("/nc:hello/nc:capabilities/nc:capability[text()='urn:ietf:params:netconf:base:1.1']", nsMgr) != null);

The reason is that the server will not be using framing if the client does not state that it is supported. Line 138 uses this flag to handle chunking with the framing protocol, though the server correctly responds without framing.

Thanks,

-- Joe

[harveechen]

Yes, I also find this. Wish to update it.

[Hevace]

Thank you @kennedyjd this resolved my problem as well.

[mpenrico-polatis]

I spotted the same problem and made the same fix in a local copy before spotting this issue (and #405) and I also changed the line that sets the _usingFramingProtocol property in the NetConfSession class to set it only if both the server AND the client report the :netconf:base:1.1 capability (as per RFC6241 section 8.1).

I also note that there should be some extra code to make the NetConfSession class more compliant with RFC6241 - e.g. if it receives a <hello> from the server with no session-id then the session should be terminated straight away.

Michael.