Baseline for querying mDNS

src/mdns.zig

@@ -1,10 +1,34 @@
 const std = @import("std");
 const util = @import("util.zig");
 
-pub fn get_mdns(domain: util.Domain) !util.IPs {
-    std.debug.print("{}\n", .{domain});
+pub fn get_mdns(domain: util.Domain, ip_ver: util.IP_VER_ENUM) !util.IPs {
+    var listener = try init(ip_ver);
+    try send_query(&listener, domain, ip_ver);
+    return receive_query(&listener);
+}
+
+fn init(ip_ver: util.IP_VER_ENUM) !std.net.Server {
+    return try std.net.Address.listen(try std.net.Address.parseIp(switch (ip_ver) {
+        util.IP_VER_ENUM.IPv4 => "0.0.0.0",
+        util.IP_VER_ENUM.IPv6 => "::",
+    }, 5353), .{});
+}
+
+fn send_query(listener: *std.net.Server, domain: util.Domain, ip_ver: util.IP_VER_ENUM) !void {
+    const header =
+        [_]u8{0x00} ** 4 ++ // transaction id + is question
+        [_]u8{ 0x00, 0x01 } ++ // 1 question
+        [_]u8{0x00} ** 6; // misc flags
+    _ = listener;
+    _ = domain;
+    _ = header;
+    _ = ip_ver;
+}
+
+fn receive_query(listener: *std.net.Server) !util.IPs {
+    _ = listener;
     return util.IPs{
-        .v4 = "stub v4",
-        .v6 = "stub v6",
+        .v4 = "",
+        .v6 = "",
     };
 }