Brief

• eRisemail system offers a feature with which user can extend or append the Anti-spam engines.
• Engine is based on C or C++, as the dynamic librarys, a .so file, on Linux.

How to use

1. Implement the features which you desire based on the framework codes(the code is in antispam directory).
2. Compile to generate the engine - a .so file.
3. For the security consideration, please stop the eRisemail service.
4. Append a record of engine to eRisemail Filter List, /etc/erisemail/mfilter.xml
5. Start the eRisemail service

Description of Filter List /etc/erisemail/mfilter.xml

• This XML file storages all eRisemail Filter engines
• All the engines that are listed will be invoked in any new MTA session (SMTP session) .
• The invoked order follows the order listed in the XML file. libso refers to the path of the engine.
• action means how to handle the spammail:
  • TAG will only toggle this mail as a spam, but still recieves and storages the mail.
  • DROP will discard spam mail directly .
• param means the paramter for the filter

Interface of Development Framework

void* mfilter_init(const char* param)

• Brief
  • Initiate the mfilter, invoked by MTA in a new session beginning
• Parameter
  • Parameter for this filter
• Return:
  • Return a filter’s handler

void mfilter_emaildomain(void* filter, const char* domain, unsigned int len)

• Brief
  • Get the local email domain name
• Parameter
  • The handler of the exist filter
• Return
  • None

void mfilter_clientip(void* filter, const char* ip, unsigned int len)

• Brief
  • Get the client site’s IP in a MTA session
• Parameter
  • The handler of the exist filter
  • A pointer of the buffer which storage the ip *　The length of buffer
• Return
  • None

void mfilter_clientdomain(void * filter, const char* domain, unsigned int len)

• Brief
  • Get the client site’s domai nname in a MTA session
• Parameter
  • The handler of the exist filter
  • A pointer of the buffer which storage the domain name
  • The length of buffer
• Return
  • None

void mfilter_mailfrom(void * filter, const char* from, unsigned int len)

• Brief
  • Get the address of “MAIL FROM”
• Parameter
  • The handler of the exist filter
  • A pointer of the buffer which storage the address of “MAIL FROM”
  • The length of buffer
• Return
  • None

void mfilter_rcptto(void * filter, const char* to, unsigned int len)

• Brief
  • Get the address of “RCPT TO”
• Parameter
  • The handler of the exist filter
  • A pointer of the buffer which storage the address of “RCPT TO”
  • The length of buffer
• Return
  • None

void mfilter_data(void * filter, const char* data, unsigned int len)

• Brief
  • Get each line of mail body
• Parameter
  • The handler of the exist filter
  • A pointer of the buffer which storage the mail body
  • The length of buffer
• Return
  • None

void mfilter_eml(void * filter, const char* emlpath, unsigned int len)

• Brief:
  • check the eml file
• Parameter:
  • The handler of the exist filter
  • A zero teminated string to the eml file path
  • The length of path string
• Return:
  • None

void mfilter_result(void * filter, int* isspam)

• Brief
  • Get the result of filter
• Parameter
  • The handler of the exist filter
  • The flag whether the mail is a spam mail. -1 is a general mail, other value is spam mail
• Return
  • None

void mfilter_exit(void * filter)

• Brief
  • Destory the filter
• Parameter
  • The handler of the exist filter
• Return
  • None