rum

What is rum:
- one process tcp redirector with socket file support and more listen ports/socket files, using libevent
- mysql reverse proxy for more mysql servers (the key to select destination server is username send by client)

Download:
rum-2.1.tar.gz
rum-2.0.tar.gz

Compilation:

apt-get install libcdb-dev
make

Usage:

./rum -s tcp:host:port [-s tcp:host:port [-s sock:path]] -d tcp:host:port [-b] [-m tcp:host:port] [-M /path/to/mysql.cdb]
	-s - listen host:port or sockfile (host muste be some ip address or 0.0.0.0 for all inerfaces)
	-d - destination host:port

	optional:
	-b - goto background
	-m - statistics port
	-M - enable handling of mysql connection with more destination servers, argument is path to cdb file

Examples:
redirect port 110 to pop3.example.net:110

rum -s tcp:0.0.0.0:110 -d tcp:pop3.example.net:110 -b

redirect port 3306 and /var/run/mysqld/mysqld.sock to 1.2.3.4:3306

rum -s tcp:localhost:3306 -s sock:/var/run/mysqld/mysqld.sock -d tcp:1.2.3.4:3306 -b

Dns lookups:
hostname -> ip resolving is done only once at start, it is not refreshed.

MySQL reverse proxy feature:

- this feature is enabled when -M /path/to/cdb is used
- cdb database is used for searching destination server from username send by client
- hashed user passwords from every mysql server must be stored in cdb database to successfuly create connections - -d must be also used as default destination server (when user is not found in cdb database rum connect to this server, but auth always fails, we need to know user password)
- in cdb file the format is:

key -> value
username -> password\0dst_server\0

password is password from mysql.user table (only mysql 4.1+ passwords are supported, old passwords are not)
dst_server is in tcp:host:port format

Why is user password need ? there is explanation:
http://forge.mysql.com/wiki/MySQL_Internals_ClientServer_Protocol#4.1_and_later

Creating cdb database
contrib/export_mysql_cdb.pl is perl script which can be run every 1 minute or so. cdb file is automatically regenerated from mysql server list and rum dont need restart.

TODO
- global and per ip connetion limit
- drop client connections if too many bufferevents are in connecting state and make it configurable from command line
- change open fds by setrlimit after start
- better log/debug messages
- modularize mysql proxy feature as shared object and use flag for make to enable it at compile time
- configurable dns refresh