feat: add strict mode switcher (#31)

Author: antongolub

.size-limit.json

@@ -9,7 +9,7 @@
       "LICENSE",
       "package-main.json"
     ],
-    "limit": "60.40 kB",
+    "limit": "61.052 kB",
     "brotli": false,
     "gzip": false
   },
@@ -18,7 +18,7 @@
     "path": [
       "target/*/core.*"
     ],
-    "limit": "41.25 kB",
+    "limit": "41.55 kB",
     "brotli": false,
     "gzip": false
   },
@@ -32,15 +32,15 @@
       "LICENSE",
       "package-main.json"
     ],
-    "limit": "18.30 kB",
+    "limit": "18.55 kB",
     "gzip": true
   },
   {
     "name": "cjs",
     "path": [
       "target/cjs"
     ],
-    "limit": "25.40 kB",
+    "limit": "25.55 kB",
     "brotli": false,
     "gzip": false
   },
@@ -49,14 +49,14 @@
     "path": [
       "target/esm"
     ],
-    "limit": "21.00 kB",
+    "limit": "21.15 kB",
     "brotli": false,
     "gzip": false
   },
   {
     "name": "libdefs",
     "path": "target/dts",
-    "limit": "7.15 kB",
+    "limit": "7.16 kB",
     "brotli": false,
     "gzip": false
   }

README.md

@@ -31,6 +31,19 @@ Temporary workaround to avoid refactoring is using `overrides` / `resolutions` i
 
 Browser-compatible core build is available as `@webpod/ip/core`: it omits `node:os` dependency and polyfills the `Buffer` API.
 
+### Strict mode
+By default, the library is in the `strict` mode that rejects non-canonical embedded IPv4 in IPv6. Switch to legacy flow if needed:
+
+```ts
+import { Address } from '@webpod/ip'
+
+Address.from('::ffff:5.6.7.8')    // ok
+Address.from('1:2:3:4::5.6.7.8')  // throws
+
+Address.strict = false
+Address.from('1:2:3:4::5.6.7.8')  // now it's fine
+```
+
 ## Usage
 The API is fully compatible with the latest `ip@2.0.1` but enforces stricter validations. See [coherence.md](./COHERENCE.md) for details.
 

src/main/ts/core.ts

@@ -157,6 +157,8 @@ export class Address {
     return o
   }
 
+  static strict = true
+
   static from(raw: Raw): Address {
     if (raw instanceof Address) return this.create(raw.big, raw.family, raw.raw)
     if (typeof raw === 'string') return this.fromString(raw.toLowerCase())
@@ -334,18 +336,18 @@ export class Address {
     if (addr === '0') return this.create(0n, 4, addr)
 
     return addr.includes(':')
-      ? this.fromIPv6(addr)
+      ? this.fromIPv6(addr, this.strict)
       : this.fromIPv4(addr)
   }
 
-  private static fromIPv6(addr: string): Address {
+  private static fromIPv6(addr: string, strict?: boolean): Address {
     const al = addr.length
     const sep = addr.indexOf('::')
     if (
       al > IPV6_LEN_LIM ||
       sep !== -1 && addr.indexOf('::', sep + 1) !== -1 // only one '::' allowed
     )
-      throw new Error(`Invalid address: ${addr}`)
+      throw new Error(`Invalid address0: ${addr}`)
 
     const groups: number[] = []
     let p = 0, gc = -1
@@ -360,15 +362,16 @@ export class Address {
         if (sep === -1 || (end !== sep && end !== sep + 1 + +last))
           throw new Error(`Invalid address: ${addr}`)
         gc = groups.length
-      } else if (last && v.includes('.')) {
-        // embedded IPv4
-        if (
-          groups.length > 6 ||
+      } else if (last && v.includes('.')) { // embedded IPv4
+        if (gc === -1 ? groups.length !== 6 : groups.length > 5)
+          throw new Error(`Invalid address: ${addr}`)
+
+        if (strict && (
           gc === groups.length ||
-          (gc === -1 && groups.length !== 6) ||
           groups[groups.length - 1] !== 0xffff ||
           groups.slice(0, -1).some(x => x !== 0)
-        ) throw new Error(`Invalid address: ${addr}`)
+        ))
+          throw new Error(`Invalid address: ${addr}`)
 
         const long = Address.normalizeToLong(v, true)
         if (long === -1) throw new Error(`Invalid address: ${addr}`)
@@ -382,7 +385,7 @@ export class Address {
       p = i + 1
     }
     const offset = 8 - groups.length
-    if (gc === -1 ? offset !== 0 : offset < 1) throw new Error(`Invalid address: ${addr}`)
+    if (gc === -1 ? offset !== 0 : offset < 1) throw new Error(`Invalid address4: ${addr}`)
 
     let big = 0n
     for (let i = 0; i < 8; i++) {

src/test/js/export.test.js

@@ -9,6 +9,7 @@ describe('core', () => {
     assert.equal(typeof core.Address, 'function', 'core.Address')
     assert.equal(typeof core.Address.fromPrefixLen, 'function', 'core.Address.fromPrefixLen')
     assert.equal(typeof core.Address.parseCidr, 'function', 'core.Address.parseCidr')
+    assert.equal(typeof core.Address.strict, 'boolean', 'core.Address.strict')
     assert.equal(typeof core.cidr, 'function', 'core.cidr')
     assert.equal(typeof core.cidrSubnet, 'function', 'core.cidrSubnet')
     assert.equal(typeof core.fromLong, 'function', 'core.fromLong')
@@ -40,6 +41,7 @@ describe('index', () => {
     assert.equal(typeof index.Address, 'function', 'index.Address')
     assert.equal(typeof index.Address.fromPrefixLen, 'function', 'index.Address.fromPrefixLen')
     assert.equal(typeof index.Address.parseCidr, 'function', 'index.Address.parseCidr')
+    assert.equal(typeof index.Address.strict, 'boolean', 'index.Address.strict')
     assert.equal(typeof index.address, 'function', 'index.address')
     assert.equal(typeof index.addresses, 'function', 'index.addresses')
     assert.equal(typeof index.cidr, 'function', 'index.cidr')