change ipip db file to custom file format
g++ -o ipipfileformatchange ipipfileformatchange.cc
usage: cidr [-i] [input file] [-o] [output file] eg. :./ipipfileformatchange -i ipip.csv -o out.csv
Get the 1st, 2nd, 7th and 15th columns of the source file and make up the new file.
change the format rule by yourself