feat(net/unstable): add ip utilities #6765

WasixXD · 2025-07-16T18:46:04Z

Hopefully closes #6722

This PR adds the isIPv4(addr: string): boolean and isIPv6(addr: string): boolean functions

codecov · 2025-07-16T18:52:53Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.14%. Comparing base (fc59ca6) to head (1cb3e4a).
⚠️ Report is 13 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6765      +/-   ##
==========================================
- Coverage   94.14%   94.14%   -0.01%     
==========================================
  Files         586      589       +3     
  Lines       42465    42540      +75     
  Branches     6701     6717      +16     
==========================================
+ Hits        39980    40049      +69     
- Misses       2435     2442       +7     
+ Partials       50       49       -1

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iuioiua

Quick pass

iuioiua · 2025-07-17T01:29:14Z

http/file_server.ts

-                return html`<a href="${link}">${escape(path)}</a>`;
-              })
-              .join("/")}/
+            Index of ${


It seems these formatting changes were made because your Deno version is out-of-date. Please update Deno and run deno fmt to revert these changes.

iuioiua · 2025-07-17T01:29:38Z

net/deno.json

  "exports": {
    ".": "./mod.ts",
    "./get-available-port": "./get_available_port.ts",
+    "./ip-utils": "./ip_utils.ts",


Suggested change

"./ip-utils": "./ip_utils.ts",

"./ip": "./ip.ts",

This is sufficient

iuioiua · 2025-07-17T01:30:04Z

net/ip_utils.ts

@@ -0,0 +1,137 @@
+// Copyright 2018-2025 the Deno authors. MIT license.
+
+const IPV4_REGEX = /^[0-9]{0,3}\.[0-9]{0,3}\.[0-9]{0,3}\.[0-9]{0,3}$/;


How did you get the regex? Genuine question. Do you have a reference that you can link to?

Got it from https://github.com/denoland/fresh/pull/3035/files i thought it was clever

iuioiua · 2025-07-17T01:30:48Z

net/ip_utils.ts

+export const distinctRemoteAddr = (
+  remoteAddr: string,
+): AddressType | undefined => {
+  if (isIPv4(remoteAddr)) {
+    return "IPv4";
+  }
+  if (isIPv6(remoteAddr)) {
+    return "IPv6";
+  }
+};


IMHO I have a feeling this function simply isn't needed and adding it now might be premature. If it were up to me, I'd wait till there's sufficient demand for such a function before adding it to the API.

iuioiua · 2025-07-17T01:31:15Z

net/ip_utils.ts

+ * @param addr - IPv4 address in a string format (e.g., "192.168.0.1").
+ * @returns a boolean indicating if the string is a IPv4 address


Suggested change

* @param addr - IPv4 address in a string format (e.g., "192.168.0.1").

* @returns a boolean indicating if the string is a IPv4 address

* @param addr IPv4 address in a string format (e.g., "192.168.0.1").

* @returns A boolean indicating if the string is a IPv4 address

Nits

iuioiua · 2025-07-17T01:31:55Z

net/ip_utils.ts

+ * @returns a boolean indicating if the string is a valid IPv4 address
+ */
+export function isValidIPv4(addr: string): boolean {
+  if (addr === "localhost") {


localhost isn't an IP address.

iuioiua · 2025-07-17T01:32:44Z

net/ip_utils.ts

+ * @param addr - IPv4 address in a string format (e.g., "192.168.0.1").
+ * @returns a boolean indicating if the string is a valid IPv4 address
+ */
+export function isValidIPv4(addr: string): boolean {


Having both isValidIPv4() and isIPv4() is confusing. We should likely just have one, and I think it should be named isIPv4(). Ditto for the IPv6 function.

iuioiua · 2025-07-17T01:32:54Z

net/ip_utils.ts

+ * @returns a boolean indicating if the string is a IPv6 address
+ */
+export function isIPv6(addr: string): boolean {
+  return addr.includes(":");


This isn't correct

iuioiua · 2025-07-17T01:34:31Z

net/ip_utils.ts

+export function matchSubnet(subnet: string, address: string): boolean {
+  // 192.128.0.1 === 192.128.0.1
+  if (subnet === address) return true;
+
+  if (subnet.includes("/")) {
+    const [range, bitStr] = subnet.split("/");
+    if (range && bitStr) {
+      const bits = parseInt(bitStr, 0);
+      const zeroes = 32 - bits;
+      const mask = bits === 0 ? 0 : (~0 << zeroes) >>> 0;
+
+      return (ipToInt(address) & mask) === (ipToInt(range) & mask);
+    }
+  }
+
+  return false;
+}


Perhaps, this can be implemented in a follow up PR, as to get this one landed sooner.

iuioiua · 2025-07-17T01:35:21Z

net/ip_utils_test.ts

+import { assert } from "../assert/assert.ts";
+import { assertEquals } from "../assert/equals.ts";
+import { assertFalse } from "../assert/false.ts";


Suggested change

import { assert } from "../assert/assert.ts";

import { assertEquals } from "../assert/equals.ts";

import { assertFalse } from "../assert/false.ts";

import { assert, assertEquals, assertFalse } from "@std/assert";

If you want.

0f-0b

The syntax of valid IP addresses is described in the URL standard. Please follow that.

Also, I think it would be a waste to parse only to throw the result away, so I suggest adding functions that return the parsed address. They can internally share an implementation like this:

Details

function ipv4Parser(str: string, buf: Uint8Array): boolean {
  // the actual implementation…
}

function ipv6Parser(str: string, buf: Uint8Array): boolean {
  // maybe reuse `ipv4Parser` for IPv6 addresses in the third form…
}

const buf = new Uint8Array(16);

export function isIPv4(str: string): boolean {
  return ipv4Parser(str, buf);
}

export function isIPv6(str: string): boolean {
  return ipv6Parser(str, buf);
}

export function parseIPv4(str: string): Uint8Array | null {
  return ipv4Parser(str, buf) ? buf.slice(0, 4) : null;
}

export function parseIPv6(str: string): Uint8Array | null {
  return ipv6Parser(str, buf) ? buf.slice(0, 16) : null;
}

export function parseIPv4Into(str: string, buf: Uint8Array): boolean {
  if (buf.length !== 4) {
    throw new TypeError("IPv4 output buffer must have a length of 4");
  }
  return ipv4Parser(str, buf);
}

export function parseIPv6Into(str: string, buf: Uint8Array): boolean {
  if (buf.length !== 16) {
    throw new TypeError("IPv6 output buffer must have a length of 16");
  }
  return ipv6Parser(str, buf);
}

iuioiua · 2025-07-17T23:40:42Z

net/ip.ts

+// Copyright 2018-2025 the Deno authors. MIT license.
+
+/**
+ * Validates whether a given string is a valid IPv4 address


Suggested change

* Validates whether a given string is a valid IPv4 address

* Validates whether a given string is a valid IPv4 address.

Nit: punctuation

iuioiua · 2025-07-17T23:41:21Z

net/ip.ts

+ * @returns A boolean indicating if the string is a valid IPv4 address
+ *
+ * @example Check if the address is a IPv4
+ * ```ts no-assert ignore


Suggested change

* ```ts no-assert ignore

* ```ts

I don't see a reason why this should be ignored. Ditto for the other snippets.

iuioiua · 2025-07-17T23:41:31Z

net/ip.ts

+ *
+ * assert(isIPv4(correctIp))
+ * assertFalse(isIPv4(incorrectIp))
+ *


Suggested change

*

Nit

iuioiua · 2025-07-17T23:43:49Z

net/ip.ts

+  const parts = addr.split(".");
+
+  if (parts.length <= 0 || parts.length < 4) return false;
+
+  for (const part of parts) {
+    const n = parseInt(part);
+
+    // n >= 256 or is negative
+    if (n >= Math.pow(2, 8) || n < 0) {
+      return false;
+    }
+  }
+
+  return true;


Suggested change

const parts = addr.split(".");

if (parts.length <= 0 || parts.length < 4) return false;

for (const part of parts) {

const n = parseInt(part);

// n >= 256 or is negative

if (n >= Math.pow(2, 8) || n < 0) {

return false;

}

}

return true;

const octets = addr.split(".");

return octets.length === 4 && octets.every((octet) => {

const n = parseInt(octet);

return n >= 0 && n <= 255;

});

This is how I would've written it. What you had before allowed strings with 4 or more octets, which is invalid.

This is very clever, i didn´t know about this every function

iuioiua · 2025-07-18T00:21:49Z

net/mod.ts

 */

 export * from "./get_available_port.ts";
+export * from "./ip.ts";


Suggested change

export * from "./ip.ts";

Unstable (new) modules aren't usually included in the mod.ts file.

iuioiua · 2025-07-18T00:22:09Z

net/deno.json

  "exports": {
    ".": "./mod.ts",
    "./get-available-port": "./get_available_port.ts",
+    "./ip": "./ip.ts",


Suggested change

"./ip": "./ip.ts",

"./unstable-ip": "./unstable_ip.ts",

I forgot that new modules need to have the "unstable" prefix.

iuioiua · 2025-07-18T00:32:07Z

net/ip.ts

+  // more than one use of ::
+  if ([...addr.matchAll(/::/g)].length > 1) {
+    return false;
+  }
+
+  const parts = addr.split(":");
+
+  // insert "" to the sequence when encountering a :: to normalize the hextets
+  for (let i = 0; i < parts.length; i++) {
+    if (parts[i] == "" && parts.length < 8) {
+      parts.splice(i, 0, "");
+    }
+  }
+
+  if (parts.length <= 0 || parts.length < 8) return false;
+
+  for (const part of parts) {
+    const n = part == "" ? 0 : parseInt(part, 16);
+
+    if (n >= Math.pow(2, 16) || n < 0 || isNaN(n)) {
+      return false;
+    }
+  }
+
+  return true;


Suggested change

// more than one use of ::

if ([...addr.matchAll(/::/g)].length > 1) {

return false;

}

const parts = addr.split(":");

// insert "" to the sequence when encountering a :: to normalize the hextets

for (let i = 0; i < parts.length; i++) {

if (parts[i] == "" && parts.length < 8) {

parts.splice(i, 0, "");

}

}

if (parts.length <= 0 || parts.length < 8) return false;

for (const part of parts) {

const n = part == "" ? 0 : parseInt(part, 16);

if (n >= Math.pow(2, 16) || n < 0 || isNaN(n)) {

return false;

}

}

return true;

// more than one use of ::

if (addr.split("::").length > 2) return false;

const hextets = addr.split(":");

// insert "" to the sequence when encountering a :: to normalize the hextets

while (hextets.length < 8) {

const idx = hextets.indexOf("");

if (idx === -1) break;

hextets.splice(idx, 0, "");

}

return hextets.length === 8 && hextets.every((hextet) => {

const n = hextet == "" ? 0 : parseInt(hextet, 16);

return n >= 0 && n <= 65535;

});

iuioiua · 2025-07-18T00:32:43Z

net/ip_test.ts

+import { isIPv4, isIPv6 } from "./ip.ts";
+import { assertEquals } from "@std/assert";
+
+Deno.test("isIPv4() returns boolean for list of IPv4s", () => {


Suggested change

Deno.test("isIPv4() returns boolean for list of IPv4s", () => {

Deno.test("isIPv4()", () => {

This should suffice. Ditto for the other test.

iuioiua · 2025-07-18T00:36:01Z

parse only to throw the result away

IMO, the current approach is fine for now.

kt3k · 2025-07-18T03:11:29Z

net/ip.ts

+  if (parts.length <= 0 || parts.length < 4) return false;
+
+  for (const part of parts) {
+    const n = parseInt(part);


because parseInt returns 1 for "1a" for example, isIPv4("1a.1.1.1") is currently true

kt3k · 2025-07-18T03:12:59Z

net/ip.ts

+    const n = parseInt(part);
+
+    // n >= 256 or is negative
+    if (n >= Math.pow(2, 8) || n < 0) {


We need to check if n is NaN. Currently isIPv4("a.b.c.d") seems returning true

kt3k · 2025-07-18T03:26:56Z

IPv6 has the form of x:x:x:x:x:x:d.d.d.d where 0 <= x <= ffff and 0 <= d <= 255.

See 3. of section 2.2 of RFC4291 for example https://www.rfc-editor.org/rfc/rfc4291#section-2.2

kt3k · 2025-07-18T03:29:20Z

net/ip.ts

+ *
+ * ```
+ */
+export function isIPv4(addr: string): boolean {


I wonder if this name conforms with our naming convention. We usually avoid capitalized acronyms (like IP). ref https://docs.deno.com/runtime/contributing/style_guide/#naming-convention

I thought about this too initially but ended up just thinking this looks fine.

iuioiua · 2025-07-21T00:50:59Z

IPv6 has the form of x:x:x:x:x:x:d.d.d.d where 0 <= x <= ffff and 0 <= d <= 255.

See 3. of section 2.2 of RFC4291 for example https://www.rfc-editor.org/rfc/rfc4291#section-2.2

That section states that this is an additional alternative form for IPv6 addresses. I used to be a network engineer and have never used that form or seen it used. I suggest not implementing for that form until there's sufficient demand for it, which, I predict there never will be.

kt3k · 2025-07-22T12:37:45Z

IPv6 has the form of x:x:x:x:x:x:d.d.d.d where 0 <= x <= ffff and 0 <= d <= 255.
See 3. of section 2.2 of RFC4291 for example https://www.rfc-editor.org/rfc/rfc4291#section-2.2

That section states that this is an additional alternative form for IPv6 addresses. I used to be a network engineer and have never used that form or seen it used. I suggest not implementing for that form until there's sufficient demand for it, which, I predict there never will be.

In Node.js, for example, dns.lookup("example.com", { family: 6, all: true }, console.log) returns the ipv6 addresses in that form.

Also URL constructor validates ip address in the hostname, and it recognizes the ipv6 address in the above form correctly (e.g. new URL("https://[::ffff:127.0.0.1]") parses to hostname: "[::ffff:7f00:1]".

WasixXD · 2025-07-29T18:13:04Z

I think this one is good to go then, WDYT? @kt3k

kt3k

LGTM. Thanks for your contribution! @WasixXD

WasixXD added 2 commits July 16, 2025 15:36

feat(net): add ip_utils

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WasixXD requested a review from kt3k as a code owner July 16, 2025 18:46

github-actions bot added the net label Jul 16, 2025

fix deno.json

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WasixXD changed the title ~~feat(net): add ip_utils~~ feat(net): added ip functionalities Jul 17, 2025

WasixXD requested a review from iuioiua July 17, 2025 16:39

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kt3k changed the title ~~feat(net): added ip functionalities~~ feat(net/unstable): added ip functionalities Jul 18, 2025

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WasixXD added 3 commits July 18, 2025 13:23

refactor functions

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kt3k changed the title ~~feat(net/unstable): added ip functionalities~~ feat(net/unstable): add ip utilities Jul 31, 2025

kt3k merged commit f79cc62 into denoland:main Jul 31, 2025
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		@@ -0,0 +1,137 @@
		// Copyright 2018-2025 the Deno authors. MIT license.

		const IPV4_REGEX = /^[0-9]{0,3}\.[0-9]{0,3}\.[0-9]{0,3}\.[0-9]{0,3}$/;

		* @param addr - IPv4 address in a string format (e.g., "192.168.0.1").
		* @returns a boolean indicating if the string is a IPv4 address

	* Validates whether a given string is a valid IPv4 address
	* Validates whether a given string is a valid IPv4 address.

	Deno.test("isIPv4() returns boolean for list of IPv4s", () => {
	Deno.test("isIPv4()", () => {

feat(net/unstable): add ip utilities #6765

feat(net/unstable): add ip utilities #6765

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