mscgen script for lvs

lvs_transp.seq

#MSC for lvs in DR transparent mode
msc{
        hscale = "2";
        Client,LB,RS,OS;

        Client=>Client [ label = "req(oip:oport)"];
        Client=>Client [ label = "routeto(LB)"];
        Client->LB [ label = "(cip:cport)->(oip:oport)"];
        LB=>LB     [ label = "iptable->fwmark(dst==oip,dst_port=oport)"];
        LB=>LB     [ label = "(cip:cport)->(oip:oport)+fwmark"];
        LB=>LB     [ label = "trick kernel to receive()"];
        LB=>LB     [ label = "is_match(LB->fwmark,packet->fwmark)"];
        LB=>LB     [ label = "belongs_to_an_active_conn?"];
        LB=>LB     [ label = "is_new_conn?"];
        LB=>LB     [ label = "is_persistent?"];
        LB=>LB     [ label = "do_schedule()"];
        LB=>LB     [ label = "decide_rs()"];
        LB=>LB     [ label = "modify-mac(vmac->rmac)"];
        
        LB->RS     [ label = "(cip:cport)->(oip:oport)"];
        --- [ label = "Packet is delivered to real server"];
        ...;
        RS=>RS     [ label = "nf_hook->dnat(oip->rip,oport->rport)"];
        RS=>RS     [ label = "receive()"];
        RS=>RS     [ label = "proxy_www(URI)"];
        RS->OS     [ label = "(rip_www:rport_www)->(oip:oport)"];
        --- [ label = "Packet is delivered to the original server"];
        OS->RS     [ label = "(oip:oport)->(rip_www:rport_www)"];
        RS=>RS     [ label = "route_to(LB or GW)"];
        --- [ label = "Packet goes back to real server"];
        RS->LB [ label = "(oip:oport)->(cip:cport)"];
        RS>>Client [ label = "possible path:(oip:oport)->(cip:cport)"];
        LB->Client [ label = "(oip:oport)->(cip:cport)"];
        --- [ label = "Packet goes back to the client"];
}