Merge pull request #1 from demskie/summarize-networks

Summarize networks

src/index.test.ts

@@ -125,3 +125,13 @@ test("sanity check rangeOfNetworks IPv6", () => {
     "2001:440:ffff:ffff::/65"
   ]);
 });
+
+test("sanity check sort", () => {
+  const output = index.sort(["192.168.2.3/31", "255.255.255.255", "192.168.0.0/16"], true);
+  expect(output).toEqual(["192.168.0.0/16", "192.168.2.3/31", "255.255.255.255/32"]);
+});
+
+test("sanity check summarize", () => {
+  const output = index.summarize(["192.168.0.0/16", "192.168.1.1", "192.168.2.3/31"], true);
+  expect(output).toEqual(["192.168.0.0/16"]);
+});

src/index.ts

@@ -327,6 +327,108 @@ export function rangeOfNetworks(startAddress: string, stopAddress: string, throw
   return results;
 }
 
+/**
+ * Sort returns an array of sorted networks
+ *
+ * @example
+ * netparser.sort(["255.255.255.255", "192.168.2.3/31", "192.168.0.0/16"])  // returns ["192.168.0.0/16", "192.168.2.3/31", "255.255.255.255/32"]
+ *
+ * @param networkAddresses - An array of addresses or subnets
+ * @param throwErrors - Stop the library from failing silently
+ *
+ * @returns An array of networks or null in case of error
+ */
+export function sort(networkAddresses: string[], throwErrors?: boolean) {
+  let subnets = new Array(networkAddresses.length) as shared.Network[];
+  let foundCIDR = false;
+  for (let i = 0; i < networkAddresses.length; i++) {
+    const netString = networkAddresses[i];
+    const addr = shared.parseAddressString(netString, throwErrors);
+    if (!addr) return null;
+    let cidr = shared.getCIDR(netString);
+    if (!cidr) {
+      if (addr.length == 4) {
+        cidr = 32;
+      } else {
+        cidr = 128;
+      }
+    } else {
+      foundCIDR = true;
+    }
+    subnets[i] = { bytes: addr, cidr: cidr };
+  }
+  subnets = shared.sortNetworks(subnets);
+  const results = new Array(subnets.length) as string[];
+  for (let i = 0; i < subnets.length; i++) {
+    let s = shared.bytesToAddr(subnets[i].bytes, throwErrors);
+    if (!s) return null;
+    results[i] = foundCIDR ? `${s}/${subnets[i].cidr}` : `${s}`;
+  }
+  return results;
+}
+
+/**
+ * Summarize returns an array of aggregates given a list of networks
+ *
+ * @example
+ * netparser.summarize(["192.168.1.1", "192.168.0.0/16", "192.168.2.3/31"])  // returns ["192.168.0.0/16"]
+ *
+ * @param networks - An array of addresses or subnets
+ * @param strict - Do not automatically mask addresses to baseAddresses
+ * @param throwErrors - Stop the library from failing silently
+ *
+ * @returns An array of networks or null in case of error
+ */
+export function summarize(networks: string[], strict?: boolean, throwErrors?: boolean) {
+  let subnets = [] as shared.Network[];
+  for (let i = 0; i < networks.length; i++) {
+    const netString = networks[i];
+    let net = shared.parseNetworkString(netString, strict, false);
+    if (!net) {
+      const addr = shared.parseAddressString(netString, throwErrors);
+      if (!addr) return null;
+      if (addr.length == 4) {
+        net = { bytes: addr, cidr: 32 };
+      } else {
+        net = { bytes: addr, cidr: 128 };
+      }
+      if (subnets.length > 0 && subnets[0].bytes.length !== net.bytes.length) {
+        if (throwErrors) throw errors.MixingIPv4AndIPv6;
+        return null;
+      }
+    }
+    subnets[i] = net;
+  }
+  subnets = shared.sortNetworks(subnets);
+  const aggregates = [] as shared.Network[];
+  for (let idx = 0; idx < subnets.length; idx++) {
+    aggregates.push(subnets[idx]);
+    let skipped = 0;
+    for (let i = idx + 1; i < subnets.length; i++) {
+      if (shared.networkContainsSubnet(subnets[idx], subnets[i])) {
+        skipped++;
+        continue;
+      }
+      if (subnets[idx].cidr === subnets[i].cidr) {
+        if (shared.networksAreAdjacent(subnets[idx], subnets[i])) {
+          subnets[idx].cidr--;
+          skipped++;
+          continue;
+        }
+      }
+      break;
+    }
+    idx += skipped;
+  }
+  const results = new Array(aggregates.length) as string[];
+  for (let i = 0; i < aggregates.length; i++) {
+    let s = shared.bytesToAddr(aggregates[i].bytes, throwErrors);
+    if (!s) return null;
+    results[i] = `${s}/${aggregates[i].cidr}`;
+  }
+  return results;
+}
+
 module.exports = {
   baseAddress,
   broadcastAddress,
@@ -339,7 +441,9 @@ module.exports = {
   networksIntersect,
   nextAddress,
   nextNetwork,
-  rangeOfNetworks
+  rangeOfNetworks,
+  sort,
+  summarize
 };
 
 // The following functions are pending an implementation:

src/shared.ts

@@ -235,7 +235,7 @@ export function networkContainsSubnet(net: Network, subnet: Network, throwErrors
   const netBytesEnd = duplicateAddress(net.bytes);
   if (!increaseAddressWithCIDR(netBytesEnd, net.cidr, throwErrors)) return false;
   const subnetBytesEnd = duplicateAddress(subnet.bytes);
-  if (!increaseAddressWithCIDR(subnet.bytes, subnet.cidr, throwErrors)) return false;
+  if (!increaseAddressWithCIDR(subnetBytesEnd, subnet.cidr, throwErrors)) return false;
   if (compareAddresses(netBytesEnd, subnetBytesEnd) < 0) return false;
   return true;
 }
@@ -266,6 +266,14 @@ export function networksIntersect(net: Network, otherNet: Network, throwErrors?:
   return true;
 }
 
+export function networksAreAdjacent(net: Network, otherNet: Network, throwErrors?: boolean) {
+  if (net.bytes.length !== otherNet.bytes.length) return false;
+  const netBytes = duplicateAddress(net.bytes);
+  if (!increaseAddressWithCIDR(netBytes, net.cidr, throwErrors)) return false;
+  if (compareAddresses(netBytes, otherNet.bytes) === 0) return true;
+  return false;
+}
+
 export function findNetworkIntersection(network: Network, otherNetworks: Network[]) {
   for (var otherNet of otherNetworks) {
     if (networksIntersect(network, otherNet)) {
@@ -297,3 +305,104 @@ export function findNetworkWithoutIntersection(network: Network, otherNetworks:
   }
   return null;
 }
+
+enum IPVersion {
+  v4,
+  v6
+}
+
+function specificNetworks(networks: Network[], version: IPVersion) {
+  const results = [] as Network[];
+  if (version === IPVersion.v4) {
+    for (let network of networks) {
+      if (network.bytes.length === 4) {
+        results.push(network);
+      }
+    }
+  } else if (version === IPVersion.v6) {
+    for (let network of networks) {
+      if (network.bytes.length === 16) {
+        results.push(network);
+      }
+    }
+  }
+  return results;
+}
+
+function radixSortNetworks(networks: Network[], version: IPVersion) {
+  if (networks.length > 0 || version === IPVersion.v4 || version === IPVersion.v6) {
+    const counts = new Array(256) as number[];
+    const offsetPrefixSum = new Array(256) as number[];
+    const byteLength = version === IPVersion.v4 ? 4 : 16;
+    const maxCIDR = version === IPVersion.v4 ? 32 : 128;
+
+    // in place swap and sort for every byte (including CIDR)
+    for (let byteIndex = 0; byteIndex <= byteLength; byteIndex++) {
+      for (let i = 0; i < counts.length; i++) {
+        counts[i] = 0;
+      }
+
+      // count each occurance of byte value
+      for (let net of networks) {
+        if (byteIndex < byteLength) {
+          net.bytes[byteIndex] = Math.min(Math.max(0, net.bytes[byteIndex]), 255);
+          counts[net.bytes[byteIndex]]++;
+        } else {
+          net.cidr = Math.min(Math.max(0, net.cidr), maxCIDR);
+          counts[net.cidr]++;
+        }
+      }
+
+      // initialize runningPrefixSum
+      let total = 0;
+      let oldCount = 0;
+      const runningPrefixSum = counts;
+      for (let i = 0; i < 256; i++) {
+        oldCount = counts[i];
+        runningPrefixSum[i] = total;
+        total += oldCount;
+      }
+
+      // initialize offsetPrefixSum (american flag sort)
+      for (let i = 0; i < 256; i++) {
+        if (i < 255) {
+          offsetPrefixSum[i] = runningPrefixSum[i + 1];
+        } else {
+          offsetPrefixSum[i] = runningPrefixSum[i];
+        }
+      }
+
+      // in place swap and sort by value
+      let idx = 0;
+      let value = 0;
+      while (idx < networks.length) {
+        if (byteIndex < byteLength) {
+          value = networks[idx].bytes[byteIndex];
+        } else {
+          value = networks[idx].cidr;
+        }
+        if (runningPrefixSum[value] !== idx) {
+          if (runningPrefixSum[value] < offsetPrefixSum[value]) {
+            let x = networks[runningPrefixSum[value]];
+            networks[runningPrefixSum[value]] = networks[idx];
+            networks[idx] = x;
+          } else {
+            idx++;
+          }
+        } else {
+          idx++;
+        }
+        runningPrefixSum[value]++;
+      }
+    }
+  }
+  return networks;
+}
+
+export function sortNetworks(networks: Network[]) {
+  const v4 = specificNetworks(networks, IPVersion.v4);
+  const v6 = specificNetworks(networks, IPVersion.v6);
+  radixSortNetworks(v4, IPVersion.v4);
+  radixSortNetworks(v6, IPVersion.v6);
+  return [...v4, ...v6];
+}