Changing the default behaviour of requests is possible using the
request attribute. This hash is indexed by the request method ("read" or
"write"), and the requested filename. If the hash contains no
entry for a given combination, the "*" entry is used. If there is
no matching entry in the hash, the command is rejected. The possible actions are described in the following table. See also Section 2.1, Policies for requests and responses.
| Action | Description |
|---|---|
| TFTP_REQ_ACCEPT | Allow the request to pass. |
| TFTP_REQ_REJECT | Reject the request and send an error message. Message code and text can be specified as second and third elements of the tuple. |
| TFTP_REQ_DROP | Drop the packet. |
| TFTP_REQ_POLICY | Call the function specified to make a decision about the event. The function receives four parameters: self, the method ("read"/"write"), the file name and the encoding used in the request. See Section 2.1, Policies for requests and responses for details. |
| TFTP_REQ_REWRITE | Rewrite filename and/or encoding and accept the packet. See Section Rewriting the request for details. |
Table 4.62. Action codes on TFTP requests
To rewrite and accept a request, the hash value must be a tuple containing TFTP_REQ_REWRITE as the first value, and the filename and encoding to be sent to the server as the second and third values.
To respond with a user-defined error code and message, the hash value must be a tuple containing TFTP_REQ_ERROR as the first value, the error code (an integer as defined by the TFTP RFC) as the second one, and the error message as the third. The session is (obviously) terminated; the TFTP server is not notified.
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