From 9104c9018561ac36ff617703250993c0af1531b5 Mon Sep 17 00:00:00 2001
From: Supereg <mail@anderl-bauer.de>
Date: Tue, 22 Sep 2020 20:56:07 +0200
Subject: [PATCH] Fixed parsing of ipv6 addresses starting or ending with
 double colon representing single zero block (fixes #5)

Additionally fixed shortening the unspecified ipv6 address
---
 src/util/domain-formatter.spec.ts | 30 +++++++++++++++++++++++++++++-
 src/util/domain-formatter.ts      | 17 ++++++++++++++---
 2 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/src/util/domain-formatter.spec.ts b/src/util/domain-formatter.spec.ts
index f728ffb..c43f69e 100644
--- a/src/util/domain-formatter.spec.ts
+++ b/src/util/domain-formatter.spec.ts
@@ -136,6 +136,25 @@ describe("domain-formatter", () => {
       expect(enlargeIPv6("::1")).toBe("0000:0000:0000:0000:0000:0000:0000:0001");
       expect(enlargeIPv6("2001:db8::ff00:42:8329")).toBe("2001:0db8:0000:0000:0000:ff00:0042:8329");
     });
+
+    it("should properly enlarge ipv6 with ending double colon", () => {
+      expect(enlargeIPv6("2001:db8:aaaa:a4c:305:ff:fe00::")).toBe("2001:0db8:aaaa:0a4c:0305:00ff:fe00:0000");
+      expect(enlargeIPv6("2001:db8:aaaa:a4c:305:ff::")).toBe("2001:0db8:aaaa:0a4c:0305:00ff:0000:0000");
+      expect(enlargeIPv6("2001:db8:aaaa:a4c:305::")).toBe("2001:0db8:aaaa:0a4c:0305:0000:0000:0000");
+    });
+
+    it("should properly enlarge ipv6 with starting double colon", () => {
+      expect(enlargeIPv6("::db8:aaaa:a4c:305:ff:fe00:0")).toBe("0000:0db8:aaaa:0a4c:0305:00ff:fe00:0000");
+      expect(enlargeIPv6("::aaaa:a4c:305:ff:fe00:0")).toBe("0000:0000:aaaa:0a4c:0305:00ff:fe00:0000");
+      expect(enlargeIPv6("::a4c:305:ff:fe00:0")).toBe("0000:0000:0000:0a4c:0305:00ff:fe00:0000");
+    });
+
+    it("should enlarged RFC 3513 examples", () => {
+      expect(enlargeIPv6("1080::8:800:200c:417a")).toBe("1080:0000:0000:0000:0008:0800:200c:417a");
+      expect(enlargeIPv6("ff01::101")).toBe("ff01:0000:0000:0000:0000:0000:0000:0101");
+      expect(enlargeIPv6("::1")).toBe("0000:0000:0000:0000:0000:0000:0000:0001");
+      expect(enlargeIPv6("::")).toBe("0000:0000:0000:0000:0000:0000:0000:0000");
+    });
   });
 
   describe(shortenIPv6, () => {
@@ -144,6 +163,8 @@ describe("domain-formatter", () => {
       expect(shortenIPv6("fe80:0000:0000:0000:72ee:50ff:fe63:d1a0")).toBe("fe80::72ee:50ff:fe63:d1a0");
       expect(shortenIPv6("0000:0000:0000:0000:0000:0000:0000:0001")).toBe("::1");
       expect(shortenIPv6("2001:0db8:0000:0000:0000:ff00:0042:8329")).toBe("2001:db8::ff00:42:8329");
+      expect(shortenIPv6("2001:0db8:0:73c8:0305:00ff:fe00:0aaa")).toBe("2001:db8::73c8:305:ff:fe00:aaa");
+      expect(shortenIPv6("2001:0db8:aaaa:0a4c:0305:00ff:fe00:0000")).toBe("2001:db8:aaaa:a4c:305:ff:fe00::");
     });
 
     it("should shorten the longest consecutive block of zeros (and only one)", () => {
@@ -154,6 +175,13 @@ describe("domain-formatter", () => {
     it("should shorten the first if there are more than one with the same length", () => {
       expect(shortenIPv6("ffff:0000:0000:ffff:ffff:0000:0000:ffff")).toBe("ffff::ffff:ffff:0:0:ffff");
     });
+
+    it("should shorten RFC 3513 examples", () => {
+      expect(shortenIPv6("1080:0:0:0:8:800:200c:417a")).toBe("1080::8:800:200c:417a");
+      expect(shortenIPv6("ff01:0:0:0:0:0:0:101")).toBe("ff01::101");
+      expect(shortenIPv6("0:0:0:0:0:0:0:1")).toBe("::1");
+      expect(shortenIPv6("0:0:0:0:0:0:0:0")).toBe("::");
+    });
   });
 
   describe(formatReverseAddressPTRName, () => {
@@ -202,7 +230,7 @@ describe("domain-formatter", () => {
 
     it("should calc netAddress for ipv6", () => {
       expect(getNetAddress("fe80::803:bfee:be23:93a8", "ffff:ffff:ffff:ffff::")).toBe("fe80::");
-      expect(getNetAddress("2003:f2:8725:ee00:1817:778e:aa58:4237", "ffff:ffff:ffff:ffff::")).toBe("2003:f2:8725:ee00::");
+      expect(getNetAddress("2001:db8:8725:ee00:1817:778e:aa58:4237", "ffff:ffff:ffff:ffff::")).toBe("2001:db8:8725:ee00::");
     });
 
     it("should catch illegal ip address format", () => {
diff --git a/src/util/domain-formatter.ts b/src/util/domain-formatter.ts
index ad2b3a4..0686a6d 100644
--- a/src/util/domain-formatter.ts
+++ b/src/util/domain-formatter.ts
@@ -137,13 +137,16 @@ export function enlargeIPv6(address: string): string {
   assert(!address.includes("."), "ipv4-mapped ipv6 addresses are currently unsupported!");
 
   const split = address.split(":");
-  assert(split.length <= 8, `Encountered invalid ipv6 with more than 8 sections (${address})!`);
 
   if (split[0] === "") {
+    split.splice(0, 1);
+
     while (split.length < 8) {
       split.unshift("0000");
     }
   } else if (split[split.length - 1] === "") {
+    split.splice(split.length -1, 1);
+
     while (split.length < 8) {
       split.push("0000");
     }
@@ -167,7 +170,9 @@ export function enlargeIPv6(address: string): string {
     }
   }
 
-  return split.join(":");
+  const result = split.join(":");
+  assert(split.length <= 8, `Resulting ipv6 address has more than 8 sections (${result})!`);
+  return result;
 }
 
 export function shortenIPv6(address: string | string[]): string {
@@ -223,7 +228,13 @@ export function shortenIPv6(address: string | string[]): string {
     }
   }
 
-  return address.join(":");
+  const result = address.join(":");
+
+  if (result === ":") { // special case for the unspecified address
+    return "::";
+  }
+
+  return result;
 }
 
 export function formatReverseAddressPTRName(address: string): string {