1. 初始化
int __init ip_vs_init(void)
{
        /*初始化src服务ip_vs_svc_table和fwm服务ip_vs_svc_fwm_table*/
        ip_vs_control_init();

        /*初始化tcp ip_vs_protocol_tcp/udp ip_vs_protocol_udp/sctp协议处理函数 */  
        ip_vs_protocol_init();

        /*初始化connection hash table: ip_vs_conn_tab*/
        ip_vs_conn_init();

    /*注册ip_vs netfilter钩子函数*/    
        nf_register_hooks(ip_vs_ops, ARRAY_SIZE(ip_vs_ops));

        /*注册ip_vs_genl用户空间配置接口ip_vs_genl_ops*/
        ip_vs_register_nl_ioctl();
}

2. 用户空间配置接口ip_vs_genl
const struct genl_ops ip_vs_genl_ops[] = { 
        {   
                /*添加虚服务, 还有set_service del_sevice*/
                .cmd    = IPVS_CMD_NEW_SERVICE,
                .flags  = GENL_ADMIN_PERM,
                .policy = ip_vs_cmd_policy,
                .doit   = ip_vs_genl_set_cmd,
        },  
        {   
                /*添加真实服务 还有set_service del_sevice*/
                .cmd    = IPVS_CMD_NEW_DEST,
                .flags  = GENL_ADMIN_PERM,
                .policy = ip_vs_cmd_policy,
                .doit   = ip_vs_genl_set_cmd,
        },  
        .......
};

# ipvsadm -A|E -t|u|f virutal-service-address:port [-s scheduler] [-p [timeout]] [-M netmask]
# ipvsadm -D -t|u|f virtual-service-address

struct ip_vs_service {
        struct hlist_node       s_list;   /* for normal service table */
        struct hlist_node       f_list;   /* for fwmark-based service table */
        atomic_t                refcnt;   /* reference counter */

        u16                     af;       /* address family */
        __u16                   protocol; /* which protocol (TCP/UDP) */
        union nf_inet_addr      addr;     /* IP address for virtual service */
        __be16                  port;     /* port number for the service */
        __u32                   fwmark;   /* firewall mark of the service */
        unsigned int            flags;    /* service status flags */
        unsigned int            timeout;  /* persistent timeout in ticks */

        struct list_head        destinations;  /* real server d-linked list */
        __u32                   num_dests;     /* number of servers */

        /* for scheduling */
        struct ip_vs_scheduler __rcu *scheduler; /* bound scheduler object */
};