[sr-dev] new module: number portability functionality

Hi all, i just commited several parts related to number portability functionality to the sr repository. This can be used as a source for routing informations related to the ownership of the number. This functionality consists of several parts. 1. pdb server This server loads serialized routing data from the disk and stores it in memory. It then listens on an UDP Port for requests containing a number and returns ID of the carrier which owns the number. This server uses the same datastructure as the carrierroute module and provides a really good performance. According our experience it usually consumes only a few percent CPU, even you use only one server for your complete callrouting cluster. 2. pdb connector module This module connects the sip-router server to the pdb server. It supports load-balancing and aggressive timeouts. Normally it not need more than a few ms to query the remote server and return the reply to the configuration script. 3. pdb tool (data compiler) This tool provides the functionality to compile the carrier and number informations into the binary data format the pdb server expect. It supports optimizing the generated trie structure, so that for example the complete number to carrier mapping for germany (app. 150 million numbers) don't need more than a few hundred megabytes. You can also combine not interesting carriers in order to save even more space and get better performance. You find the module in the modules/pdb directory, the server and tool is in utils/pdbt. This directory also contains documentation (README for module, utils/pdbt/docs/* for data format and network protocol). We decided to develop a custom solution as none of the alternatives that were evaluated (like enum over DNS, databases e.g. berkeley DB, some commercial products) provides the wanted performance, failure tolerance and storage efficieny. This module has been in production use since some time, so if you find some bugs they are most probably introduced from me because of the sr adaption. The original implementation was done from Hardy Kahl. Best regards, Henning Westerholt -- Henning Westerholt - Development Consumer Products / Consumer Core 1&1 Internet AG, Ernst-Frey-Str. 9, 76135 Karlsruhe, Germany