fix(utils/ipaddr): support IPv6-mapped IPv4 address (#3727)

usualoma · web-flow · commit af5affc5b48a · 2024-12-06T16:08:20.000+09:00
diff --git a/src/middleware/ip-restriction/index.test.ts b/src/middleware/ip-restriction/index.test.ts
@@ -100,6 +100,10 @@ describe('isMatchForRule', () => {
   it('Static Rules', async () => {
     expect(await isMatch({ addr: '192.168.2.1', type: 'IPv4' }, '192.168.2.1')).toBeTruthy()
     expect(await isMatch({ addr: '1234::5678', type: 'IPv6' }, '1234::5678')).toBeTruthy()
+    expect(
+      await isMatch({ addr: '::ffff:127.0.0.1', type: 'IPv6' }, '::ffff:127.0.0.1')
+    ).toBeTruthy()
+    expect(await isMatch({ addr: '::ffff:127.0.0.1', type: 'IPv6' }, '::ffff:7f00:1')).toBeTruthy()
   })
   it('Function Rules', async () => {
     expect(await isMatch({ addr: '0.0.0.0', type: 'IPv4' }, () => true)).toBeTruthy()
diff --git a/src/utils/ipaddr.test.ts b/src/utils/ipaddr.test.ts
@@ -1,4 +1,5 @@
 import {
+  convertIPv4BinaryToString,
   convertIPv4ToBinary,
   convertIPv6BinaryToString,
   convertIPv6ToBinary,
@@ -13,12 +14,14 @@ describe('expandIPv6', () => {
     expect(expandIPv6('2001:2::')).toBe('2001:0002:0000:0000:0000:0000:0000:0000')
     expect(expandIPv6('2001:2::')).toBe('2001:0002:0000:0000:0000:0000:0000:0000')
     expect(expandIPv6('2001:0:0:db8::1')).toBe('2001:0000:0000:0db8:0000:0000:0000:0001')
+    expect(expandIPv6('::ffff:127.0.0.1')).toBe('0000:0000:0000:0000:0000:ffff:7f00:0001')
   })
 })
 describe('distinctRemoteAddr', () => {
   it('Should result be valid', () => {
     expect(distinctRemoteAddr('1::1')).toBe('IPv6')
     expect(distinctRemoteAddr('::1')).toBe('IPv6')
+    expect(distinctRemoteAddr('::ffff:127.0.0.1')).toBe('IPv6')
 
     expect(distinctRemoteAddr('192.168.2.0')).toBe('IPv4')
     expect(distinctRemoteAddr('192.168.2.0')).toBe('IPv4')
@@ -35,13 +38,27 @@ describe('convertIPv4ToBinary', () => {
     expect(convertIPv4ToBinary('0.0.1.0')).toBe(1n << 8n)
   })
 })
+
+describe('convertIPv4ToString', () => {
+  // add tons of test cases here
+  test.each`
+    input        | expected
+    ${'0.0.0.0'} | ${'0.0.0.0'}
+    ${'0.0.0.1'} | ${'0.0.0.1'}
+    ${'0.0.1.0'} | ${'0.0.1.0'}
+  `('convertIPv4ToString($input) === $expected', ({ input, expected }) => {
+    expect(convertIPv4BinaryToString(convertIPv4ToBinary(input))).toBe(expected)
+  })
+})
+
 describe('convertIPv6ToBinary', () => {
   it('Should result is valid', () => {
     expect(convertIPv6ToBinary('::0')).toBe(0n)
     expect(convertIPv6ToBinary('::1')).toBe(1n)
 
     expect(convertIPv6ToBinary('::f')).toBe(15n)
     expect(convertIPv6ToBinary('1234:::5678')).toBe(24196103360772296748952112894165669496n)
+    expect(convertIPv6ToBinary('::ffff:127.0.0.1')).toBe(281472812449793n)
   })
 })
 
@@ -55,6 +72,7 @@ describe('convertIPv6ToString', () => {
     ${'2001:2::'}                                | ${'2001:2::'}
     ${'2001::db8:0:0:0:0:1'}                     | ${'2001:0:db8::1'}
     ${'1234:5678:9abc:def0:1234:5678:9abc:def0'} | ${'1234:5678:9abc:def0:1234:5678:9abc:def0'}
+    ${'::ffff:127.0.0.1'}                        | ${'::ffff:127.0.0.1'}
   `('convertIPv6ToString($input) === $expected', ({ input, expected }) => {
     expect(convertIPv6BinaryToString(convertIPv6ToBinary(input))).toBe(expected)
   })
diff --git a/src/utils/ipaddr.ts b/src/utils/ipaddr.ts
@@ -12,6 +12,15 @@ import type { AddressType } from '../helper/conninfo'
  */
 export const expandIPv6 = (ipV6: string): string => {
   const sections = ipV6.split(':')
+  if (IPV4_REGEX.test(sections.at(-1) as string)) {
+    sections.splice(
+      -1,
+      1,
+      ...convertIPv6BinaryToString(convertIPv4ToBinary(sections.at(-1) as string)) // => ::7f00:0001
+        .substring(2) // => 7f00:0001
+        .split(':') // => ['7f00', '0001']
+    )
+  }
   for (let i = 0; i < sections.length; i++) {
     const node = sections[i]
     if (node !== '') {
@@ -70,12 +79,30 @@ export const convertIPv6ToBinary = (ipv6: string): bigint => {
   return result
 }
 
+/**
+ * Convert a binary representation of an IPv4 address to a string.
+ * @param ipV4 binary IPv4 Address
+ * @return IPv4 Address in string
+ */
+export const convertIPv4BinaryToString = (ipV4: bigint): string => {
+  const sections = []
+  for (let i = 0; i < 4; i++) {
+    sections.push((ipV4 >> BigInt(8 * (3 - i))) & 0xffn)
+  }
+  return sections.join('.')
+}
+
 /**
  * Convert a binary representation of an IPv6 address to a string.
  * @param ipV6 binary IPv6 Address
  * @return normalized IPv6 Address in string
  */
 export const convertIPv6BinaryToString = (ipV6: bigint): string => {
+  // IPv6-mapped IPv4 address
+  if (ipV6 >> 32n === 0xffffn) {
+    return `::ffff:${convertIPv4BinaryToString(ipV6 & 0xffffffffn)}`
+  }
+
   const sections = []
   for (let i = 0; i < 8; i++) {
     sections.push(((ipV6 >> BigInt(16 * (7 - i))) & 0xffffn).toString(16))
