awk函数实现将点分式形式的掩码转换为十进制形式的掩码

在用awk处理文本时，需要将源数据为点分式形式的掩码转换为十进制形式的掩码，下边的函数可简单实现：

• 转换功能函数cdr2mask

function cdr2mask(mask_point) {
    num=gsub("255.","",mask_point)
    #print mask_point
    gsub("[\\.]0","",mask_point)
    #print mask_point
    mask=mask_point-0
    for(i = 0;mask > 0;i++){
        if (mask % 2^(7-i) == 0){
            i++
            break
        }else{
            mask -= 2^(7-i)
        }
    }
    mask_decade = 8*num + i
    return mask_decade
}

• 源数据

 <ZJHZ-BA-IPNET-RT07-NE40EX16A>dis cur configuration  bgp
#
 ipv4-family vpn-instance ChinaMobile_IMS_Media
  network 10.3.160.20 0.0.0.0
  network 10.3.160.48 255.255.255.252
  network 10.3.160.56 255.255.255.128

• awk完整程序

#!/bin/awk -f
# author: wholj
# date: 2018-09-05

# awk开始处理文本

# JSON构造函数
function json(dict,end_tag)
{
    count=0
    printf("\t{\n")
    for(key in dict){
        ++count
        if(count==length(dict)){
            printf("\t\t\"%s\":\"%s\"\n",key,dict[key])
        }
        else{
            printf("\t\t\"%s\":\"%s\",\n",key,dict[key])
        }
    }
    if(end_tag==1){
        printf("\t}\n")
    }
    else{
        printf("\t},\n")
    }
}

# 将点分式形式的掩码转换为十进制形式的掩码（255.255.255.0 --> 24）
function cdr2mask(mask_point) {
    num=gsub("255.","",mask_point)
    #print mask_point
    gsub("[\\.]0","",mask_point)
    #print mask_point
    mask=mask_point-0
    for(i = 0;mask > 0;i++){
        if (mask % 2^(7-i) == 0){
            i++
            break
        }else{
            mask -= 2^(7-i)
        }
    }
    mask_decade = 8*num + i
    return mask_decade
}

# awk开始处理传入的文本文件
{
    # 将文件中的\r换行替换为\n
    gsub("\r","\n",$0)
    # 获取VPN的名称
    if ( NF==3 && $1~/ipv4-family/ && $2~/vpn-instance/ ){
        #print $0
        vpn_name = $3
        #print vpn_name
    }
    # 得到路由信息
    if( NF==3 && $1~/network/ && $2~/[0-9]+.[0-9]+.[0-9]+.[0-9]+/ && $3~/[0-9]+.[0-9]+.[0-9]+.[0-9]+/ ){
        #print $0
        #print cdr2mask($3)
        route_info[vpn_name, NR] = vpn_name"|"$2"/"cdr2mask($3)
        #print route_info[vpn_name, NR]
    }
}
END{
    print "["
    row_count=0
    # 遍历数组，组合json格式
    for( route in route_info ){
        ++row_count
        split(route_info[route], route_arr, "|")
        #print route_arr[1]
        #print route_arr[2]
        route_dict["vpn_name"]=route_arr[1]
        route_dict["route_info"]=route_arr[2]
        if ( row_count==length(route_info) ){
            json(route_dict,"1")
        }else{
            json(route_dict,"0")
        }
    }
    print "]"
}

• 测试结果

[
    {
        "vpn_name":"ChinaMobile_IMS_Media",
        "route_info":"10.3.160.20/0"
    },
	{
        "vpn_name":"ChinaMobile_IMS_Media",
        "route_info":"10.3.160.48/30"
    },
	{
        "vpn_name":"ChinaMobile_IMS_Media",
        "route_info":"10.3.160.56/25"
    }
]