perf: avoid repeated client scans during CIDR changes (#2707)

* perf: avoid repeated client scans during CIDR changes (#2706)

* refactor: retain CIDR change guards

* perf: avoid repeated client reads during migration

---------

Co-authored-by: potatosips <potatosips@users.noreply.github.com>

src/server/api/setup/migrate.post.ts

@@ -5,7 +5,7 @@ import { z } from 'zod';
 
 import Database from '#server/utils/Database';
 import { defineSetupEventHandler } from '#server/utils/handler';
-import { nextIP } from '#server/utils/ip';
+import { nextIPFromUsedAddresses } from '#server/utils/ip';
 import { FileSchema, validateZod } from '#server/utils/types';
 
 export default defineSetupEventHandler('migrate', async ({ event }) => {
@@ -58,6 +58,9 @@ export default defineSetupEventHandler('migrate', async ({ event }) => {
       `/${ipv4Cidr.prefix}`,
     ipv6Cidr: ipv6Cidr.cidr,
   });
+  const ipv6Addresses = new Set(
+    (await Database.clients.getAll()).map((client) => client.ipv6Address)
+  );
 
   for (const clientId in oldConfig.clients) {
     const clientConfig = oldConfig.clients[clientId];
@@ -66,15 +69,14 @@ export default defineSetupEventHandler('migrate', async ({ event }) => {
       continue;
     }
 
-    const clients = await Database.clients.getAll();
-
-    const ipv6Address = nextIP(6, ipv6Cidr, clients);
+    const ipv6Address = nextIPFromUsedAddresses(6, ipv6Cidr, ipv6Addresses);
 
     await Database.clients.createFromExisting({
       ...clientConfig,
       ipv4Address: clientConfig.address,
       ipv6Address,
     });
+    ipv6Addresses.add(ipv6Address);
   }
 
   await Database.general.setSetupStep(0);

src/server/database/repositories/interface/service.ts

@@ -4,7 +4,7 @@ import { parseCidr } from 'cidr-tools';
 import { wgInterface } from './schema';
 import type { InterfaceCidrUpdateType, InterfaceUpdateType } from './types';
 
-import { nextIP } from '#server/utils/ip';
+import { nextIPFromUsedAddresses } from '#server/utils/ip';
 import { client as clientSchema } from '#db/schema';
 import type { DBType } from '#db/sqlite';
 
@@ -93,21 +93,36 @@ export class InterfaceService {
         .execute();
 
       const clients = await tx.query.client.findMany().execute();
+      const ipv4Addresses = new Set(
+        clients.map((client) => client.ipv4Address)
+      );
+      const ipv6Addresses = new Set(
+        clients.map((client) => client.ipv6Address)
+      );
 
       for (const client of clients) {
-        // TODO: optimize
-        const clients = await tx.query.client.findMany().execute();
-
         // only calculate ip if cidr has changed
 
         let nextIpv4 = client.ipv4Address;
         if (data.ipv4Cidr !== oldCidr.ipv4Cidr) {
-          nextIpv4 = nextIP(4, parseCidr(data.ipv4Cidr), clients);
+          nextIpv4 = nextIPFromUsedAddresses(
+            4,
+            parseCidr(data.ipv4Cidr),
+            ipv4Addresses
+          );
+          ipv4Addresses.add(nextIpv4);
+          ipv4Addresses.delete(client.ipv4Address);
         }
 
         let nextIpv6 = client.ipv6Address;
         if (data.ipv6Cidr !== oldCidr.ipv6Cidr) {
-          nextIpv6 = nextIP(6, parseCidr(data.ipv6Cidr), clients);
+          nextIpv6 = nextIPFromUsedAddresses(
+            6,
+            parseCidr(data.ipv6Cidr),
+            ipv6Addresses
+          );
+          ipv6Addresses.add(nextIpv6);
+          ipv6Addresses.delete(client.ipv6Address);
         }
 
         await tx

src/server/utils/ip.ts

@@ -13,15 +13,24 @@ export function nextIP(
   version: 4 | 6,
   cidr: ParsedCidr,
   clients: ClientNextIpType[]
+) {
+  const usedAddresses = new Set(
+    clients.map((client) => client[`ipv${version}Address`])
+  );
+
+  return nextIPFromUsedAddresses(version, cidr, usedAddresses);
+}
+
+export function nextIPFromUsedAddresses(
+  version: 4 | 6,
+  cidr: ParsedCidr,
+  usedAddresses: Set<string>
 ) {
   let address;
   for (let i = cidr.start + 2n; i <= cidr.end - 1n; i++) {
     const currentIp = stringifyIp({ number: i, version: version });
-    const client = clients.find((client) => {
-      return client[`ipv${version}Address`] === currentIp;
-    });
 
-    if (!client) {
+    if (!usedAddresses.has(currentIp)) {
       address = currentIp;
       break;
     }

src/test/unit/ip.spec.ts

@@ -0,0 +1,40 @@
+import { parseCidr } from 'cidr-tools';
+import { describe, expect, test } from 'vitest';
+
+import { nextIPFromUsedAddresses } from '#server/utils/ip';
+
+describe('nextIPFromUsedAddresses', () => {
+  test('returns the first available address without scanning client records', () => {
+    const usedAddresses = new Set(['10.0.0.2', '10.0.0.3']);
+
+    expect(
+      nextIPFromUsedAddresses(4, parseCidr('10.0.0.0/29'), usedAddresses)
+    ).toBe('10.0.0.4');
+  });
+
+  test('throws when every usable address is allocated', () => {
+    const usedAddresses = new Set([
+      '10.0.0.2',
+      '10.0.0.3',
+      '10.0.0.4',
+      '10.0.0.5',
+      '10.0.0.6',
+    ]);
+
+    expect(() =>
+      nextIPFromUsedAddresses(4, parseCidr('10.0.0.0/29'), usedAddresses)
+    ).toThrow('Maximum number of clients reached');
+  });
+
+  test('supports replacing addresses while retaining the current allocation state', () => {
+    const cidr = parseCidr('10.0.0.0/29');
+    const usedAddresses = new Set(['10.0.0.2', '10.0.0.3']);
+
+    const firstReplacement = nextIPFromUsedAddresses(4, cidr, usedAddresses);
+    usedAddresses.add(firstReplacement);
+    usedAddresses.delete('10.0.0.2');
+
+    expect(firstReplacement).toBe('10.0.0.4');
+    expect(nextIPFromUsedAddresses(4, cidr, usedAddresses)).toBe('10.0.0.2');
+  });
+});