From a032fd01e88be2c6e8d0cfb0ccd3d9859c9dffdc Mon Sep 17 00:00:00 2001
From: Stephen Gregoratto <dev@sgregoratto.me>
Date: Sat, 18 Sep 2021 23:26:55 +1000
Subject: [PATCH] Resolve scope IDs using IPv6 sockets

On certain systems (Solaris), resolving the scope id from an interface
name can only be done on AF_INET-domain sockets. While we're here,
simplify the test while we're here, since there's only one address.

Also note that the loopback interface name is not stable across OSs.
BSDs and Solaris use `lo0` whilst Linux uses `l0`.
---
 lib/std/x/os/net.zig | 28 ++++++++++++----------------
 1 file changed, 12 insertions(+), 16 deletions(-)

diff --git a/lib/std/x/os/net.zig b/lib/std/x/os/net.zig
index 5b06d492a54767cf6ec65453a1e20da46ef08cc8..a529396c3c89e00ccb618895cec5d21c051d96f3 100644
--- a/lib/std/x/os/net.zig
+++ b/lib/std/x/os/net.zig
@@ -27,7 +27,7 @@ pub fn resolveScopeId(name: []const u8) !u32 {
             return rc;
         }
 
-        const fd = try os.socket(os.AF.UNIX, os.SOCK.DGRAM, 0);
+        const fd = try os.socket(os.AF.INET, os.SOCK.DGRAM, 0);
         defer os.closeSocket(fd);
 
         var f: os.ifreq = undefined;
@@ -566,21 +566,17 @@ test "ipv6: parse & format" {
 
 test "ipv6: parse & format addresses with scope ids" {
     if (!have_ifnamesize) return error.SkipZigTest;
-
-    const inputs = [_][]const u8{
-        "FF01::FB%lo",
-    };
-
-    const outputs = [_][]const u8{
-        "ff01::fb%1",
+    const iface = if (native_os.tag == .linux)
+        "lo"
+    else
+        "lo0";
+    const input = "FF01::FB%" ++ iface;
+    const output = "ff01::fb%1";
+
+    const parsed = IPv6.parse(input) catch |err| switch (err) {
+        error.InterfaceNotFound => return,
+        else => return err,
     };
 
-    for (inputs) |input, i| {
-        const parsed = IPv6.parse(input) catch |err| switch (err) {
-            error.InterfaceNotFound => continue,
-            else => return err,
-        };
-
-        try testing.expectFmt(outputs[i], "{}", .{parsed});
-    }
+    try testing.expectFmt(output, "{}", .{parsed});
 }
-- 
2.54.0