remove unneccessary ip check calculation for linux
remove unneccessary ip check calculation for linux

left2right/tcpcopy,caosiyang/tcpcopy,wfxiang08/tcpcopy,u20024804/tcpcopy,caosiyang/tcpcopy,ycaihua/tcpcopy,sshling/tcpcopy,liviusATnetskope/second,eliteYang/tcpcopy,daodaoliang/tcpcopy,horryq/tcpcopy,liviusATnetskope/second,sshling/tcpcopy,eliteYang/tcpcopy,daodaoliang/tcpcopy,ycaihua/tcpcopy,u20024804/tcpcopy,left2right/tcpcopy,horryq/tcpcopy,wfxiang08/tcpcopy