Message modification functions
The message modification functions change the message content and attributes. The functions are called only in by the xxfi_eom function. Message modification functions can invoke additional communication with the mail transfer agent (MTA). These functions return either the MI_SUCCESS or MI_FAILURE value to indicate the status of the operation.
Note: Message data (senders, recipients, headers, and body chunks)
that are passed to the message modification functions in the parameters
is copied and do not need to be preserved (allocated memory can be
freed).
To call a message modification function, the filter must set the appropriate flag in the description that is passed to the smfi_register function. If the flag is not set, MTA treats the call to the function as a failure of the filter, and terminates the connection.
Note: The status
returned by the function indicates whether the message filter was
successfully sent to the MTA. The status does not indicate whether
the MTA performed the requested operation. For example, the smfi_header function,
when called with an illegal header name, returns the MI_SUCCESS flag
even though the MTA can later decline to add the illegal header.
| Item | Description | function |
|---|---|---|
| smfi_addheader | The smfi_addheader function adds a header to the message. | SMFIF_ADDHDRS |
| smfi_chgheader | The smfi_chgheader function modifies or deletes a header. | SMFIF_CHGHDRS |
| smfi_insheader | The smfi_insheader function inserts a header into the message. | SMFIF_ADDHDRS |
| smfi_chgfrom | The smfi_chgfrom function modifies the envelope sender address. | SMFIF_CHGFROM |
| smfi_addrcpt | The smfi_addrcpt function adds a recipient to the envelope. | SMFIF_ADDRCPT |
| smfi_addrcpt_par | The smfi_addrcpt_par function adds a recipient including extended simple mail transfer protocol (ESMTP) parameter to the envelope. | SMFIF_ADDRCPT_PAR |
| smfi_delrcpt | The smfi_delrcpt function deletes a recipient from the envelope. | SMFIF_DELRCPT |
| smfi_replacebody | The smfi_replacebody function replaces the body of the message. | SMFIF_CHGBODY |