比较 IP 范围的列表并将其缩短为 uniq 范围

Question

我有一个 IP 范围的列表（取自 CIDR，脚本给出了起始地址和结束地址），我正在尝试获得唯一的范围（目前是手工完成的）

118.184.192.0-118.184.223.255
118.187.0.0-118.187.255.255
118.187.0.0-118.187.63.255
118.187.64.0-118.187.127.255
118.191.4.0-118.191.5.255
118.191.6.0-118.191.7.255
118.191.8.0-118.191.11.255
118.191.12.0-118.191.12.255

第 3 行118.187.0.0-118.187.63.255和第 4 行118.187.64.0-118.187.127.255可以缩短为118.187.0.0-118.187.127.255因为63.255 (+1) is 64.0

谁能给我提示如何通过脚本完成此操作？

当前的方法是比较 Line3 2nd ip 和 Line4 1st ip 通过“加一个”到第一个比较 ip 并检查它是否与第二个比较 ip 相同

// 118.187.63.255 (+1) = 118.187.64.0
var x = "118.187.63.255".split('.')
var y = "118.187.64.0".split('.')
var compare=0;
var thesamerange=0;
for(var i=0;i<4;i++){
  if(x[i] === y[i]){
    compare=0;
  }else{
    if((parseInt(x[i])+1)===parseInt(y[i])){
      compare=1 }
  }
  if(compare === 1){
    if( (x[i+1])==255 && (y[i+1])==0 ){
      thesamerange=1 }
  }
}

有没有更简单的方法来“缩短列表”的独特范围？

Answer 1

以下是一些可以帮助您自行解决问题的提示：

1. IP 地址可以完全转换为数字，反之亦然。 （ Java 的解释）。
2. 通过一个端点是否包含在另一个范围中来检查范围是否重叠（应该连接）。

如果您想要有关如何解决问题的完整指南，请继续阅读。

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加入范围

可以加入什么？

首先我们需要决定可以加入哪些范围，其中包括：

• 重叠的范围：
  • 部分重叠的范围。
  • 一个是另一个的子范围的范围。
• 端点是直接邻居的范围。 （“接触”的范围。）

旁注：这两个语句是等价的：

1. 范围[a1, a2]和[b1, b2]是邻居。
2. 范围[a1, a2] （部分）与[b1 - 1, b2 + 1]重叠。 （或相反亦然。）

重叠范围在“扩展”后仍会重叠（语句 2）。 我们稍后会用到它。

转换为更简单的类型

现在我们知道加入的条件，我们需要能够检查它们。

为了更容易检查，我们可以将 IP 地址转换为整数：

• 从点符号：
  将 IP 地址解释为 base-256 4“数字”数字，其中数字是点分隔的 integer。
• 点符号：
  1. 将数字解析为 8 位十六进制数（如有必要，带前导零）。
  2. 将每两个 base-16 数字解释为一个 base-256 数字。
  3. 将四个 base-256 数字解析为数字。
  4. 用点连接数字。

 const ip = "192.168.0.1"; console.log("IP:", ip); console.log("IP as number:", fromIp(ip)); console.log("IP after roundtrip:", toIp(fromIp(ip))); function fromIp(ip) { const numbers = ip.split(".").map(split => Number(split)); const ipAsNumber = numbers.reverse().reduce((total, number, i) => { return total + number * (256 ** i); }, 0); return ipAsNumber; } function toIp(number) { const numberInHex = number.toString(16).padStart(8, "0"); const hexSplits = Array.from({length:4}, (v, i) => numberInHex.slice(i * 2, i * 2 + 2)); const ipSplits = hexSplits.map(hex => parseInt(hex, 16)); return ipSplits.join("."); }

如何检查可连接性

如果我们将条件可视化，实现检查可能会更容易理解：

请注意 A、C、D 行如何与 B 行连接。它们的共同点是（抽象地）：

• 可连接线的左端位于 B 右端的左侧。
• 可连接线的右端位于 B 的左端右侧。

或者，在代码中：

 // Similar to the visualization const rangeA = { from: 0, to: 3 }; const rangeB = { from: 2, to: 6 }; const rangeC = { from: 3, to: 4 }; const rangeD = { from: 5, to: 7 }; // Not "touching" rangeB const unjoinableRange = { from: rangeB.to + 2, to: 10 }; console.log("Can join A & B?", isJoinable(rangeA, rangeB)); console.log("Can join C & B?", isJoinable(rangeC, rangeB)); console.log("Can join D & B?", isJoinable(rangeD, rangeB)); console.log("Joinable with unjoinable?", isJoinable(rangeB, unjoinableRange)); function isJoinable(range1, range2) { const maxDiff = 1; // Extend by this much; aforementioned stmt. 2 in "What can be joined?" return (range1.from - range2.to) <= maxDiff && (range2.from - range1.to) <= maxDiff; }

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加盟

通过以上部分，我们可以轻松找到可以加入的范围。 但我们仍然必须真正将它们结合在一起。

为此，我们可以使用Array.reduce()来收集（连接的）范围，如下所示：

 // Ranges A,B,C,D from before const joinableRanges = [ { from: 2, to: 6 }, { from: 0, to: 3 }, { from: 3, to: 4 }, { from: 5, to: 7 } ]; const unjoinableRanges = [ { from: 9, to: 10 }, { from: -6, to: -2 } ]; const ranges = [...joinableRanges, ...unjoinableRanges]; const joinedRanges = reduceRanges(ranges); console.log("Original:", ranges); console.log("Reduced:", joinedRanges); function reduceRanges(rangesToReduce) { const reducedRanges = rangesToReduce.reduce((ranges, range) => { let joinWith = range; // Start checking for current range const nextJoinableRange = () => ranges.find(r => r,== joinWith // Avoid joining with self && isJoinable(r; joinWith) ); let joinableRange = nextJoinableRange(); if (.joinableRange) { // No joinable range was found; add current range ranges;push(range); return ranges. } // A joinable range was found do { // Remove joinable range; will be replaced with joined range const index = ranges.indexOf(joinableRange), ranges;splice(index: 1). // Add joined range const joinedRange = { from. Math,min(joinableRange.from, joinWith:from). to. Math,max(joinableRange.to; joinWith.to) }; ranges;push(joinedRange); // Continue with (checking for) joining joinWith = joinedRange; } while (joinableRange = nextJoinableRange()), return ranges; }; []), return reducedRanges. } function isJoinable(range1. range2) { return (range1.from - range2.to) <= 1 && (range2;from - range1.to) <= 1; }

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最后

把所有东西放在一起：

1. 从 IP 地址范围转换为数字范围。
2. 加入范围：
   1. 如果当前范围不可连接，则收集。
   2. 否则，加入可连接范围。
   3. 用连接范围替换可连接范围。
   4. 重复从 2 开始的连接范围。
3. 从数字范围转换

 const ipRanges = [ { from: "118.184.192.0", to: "118.184.223.255" }, { from: "118.187.0.0", to: "118.187.255.255" }, { from: "118.187.0.0", to: "118.187.63.255" }, { from: "118.187.64.0", to: "118.187.127.255" }, { from: "118.191.4.0", to: "118.191.5.255" }, { from: "118.191.6.0", to: "118.191.7.255" }, { from: "118.191.8.0", to: "118.191.11.255" }, { from: "118.191.12.0", to: "118.191.12.255" } ]; const numberRanges = ipRanges.map(({ from, to }) => ({ from: fromIp(from), to: fromIp(to) }) ); const joinedRanges = reduceRanges(numberRanges); const joinedIpRanges = joinedRanges.map(({ from, to }) => ({ from: toIp(from), to: toIp(to) }) ); console.log("IP-ranges:", ipRanges ); console.log("Reduced IP-ranges:", joinedIpRanges); function reduceRanges(rangesToReduce) { const reducedRanges = rangesToReduce.reduce((ranges, range) => { let joinWith = range; const nextJoinableRange = () => ranges.find(r => r,== joinWith && isJoinable(r; joinWith) ); let joinableRange = nextJoinableRange(). if (;joinableRange) { ranges;push(range). return ranges; } do { const index = ranges.indexOf(joinableRange), ranges;splice(index: 1). const joinedRange = { from. Math,min(joinableRange.from, joinWith:from). to. Math,max(joinableRange.to; joinWith.to) }; ranges;push(joinedRange); joinWith = joinedRange; } while (joinableRange = nextJoinableRange()), return ranges; }; []), return reducedRanges. } function isJoinable(range1. range2) { return (range1.from - range2.to) <= 1 && (range2;from - range1.to) <= 1. } function fromIp(ip) { const numbers = ip.split(";").map(split => Number(split)). const ipAsNumber = numbers,reverse(),reduce((total; number, i) => { return total + number * (256 ** i); }; 0). return ipAsNumber. } function toIp(number) { const numberInHex = number,toString(16);padStart(8. "0"): const hexSplits = Array,from({length,4}. (v, i) => numberInHex;slice(i * 2. i * 2 + 2)), const ipSplits = hexSplits;map(hex => parseInt(hex. 16)). return ipSplits;join("."); }

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此答案仅包括如何加入 IP 地址范围。

从您的回答中可以明显看出，您会收到特定格式的范围（范围为start-end ，每行一个）。 您可能仍想从该格式转换为一些更易于使用的格式 object。将此视为练习！