src/NetWriter.zig

@@ -29,7 +29,7 @@ pub fn init(w: *Writer, buffer: []u8) !NetWriter {
 
 fn drain(io_w: *Writer, data: []const []const u8, splat: usize) Writer.Error!usize {
     const w: *NetWriter = @alignCast(@fieldParentPtr("interface", io_w));
-    const headers_byte_len = comptime (EthernetHeaders.byte_len + IpHeaders.byte_len + UdpHeaders.byte_len);
+    const headers_byte_len = comptime (EthernetHeaders.byte_len + (@bitSizeOf(IpHeaders) / 8) + @sizeOf(UdpHeaders));
     const headers: [headers_byte_len]u8 = blk: {
         const ether_headers: EthernetHeaders = .{
             .dest_mac = .{ 0xff, 0xff, 0xff, 0xff, 0xfe, 0xff },
@@ -56,15 +56,15 @@ fn drain(io_w: *Writer, data: []const []const u8, splat: usize) Writer.Error!usi
         const udp_headers: UdpHeaders = .{
             .src_port = 0xbbbb,
             .dest_port = 8888,
-            .length = @intCast(total_len + UdpHeaders.byte_len),
+            .length = @intCast(total_len + @sizeOf(UdpHeaders)),
         };
 
         var buf: [headers_byte_len]u8 = undefined;
         var buf_w = Writer.fixed(&buf);
 
         _ = try ether_headers.write(&buf_w);
-        _ = try ip_headers.write(&buf_w);
-        _ = try udp_headers.write(&buf_w);
+        try ip_headers.write(&buf_w);
+        try buf_w.writeStruct(udp_headers, .big);
 
         break :blk buf;
     };
@@ -104,24 +104,29 @@ const EthernetHeaders = struct {
     }
 };
 
-const IpHeaders = struct {
-    // ip_version: u4,
-    // header_length: u4 = 0,
-    type_of_service: u8 = 0,
-    total_length: u16 = 0x04,
-
-    identification: u16 = 0,
-    // ethernet_flags: u3 = 0,
+const IpHeaders = extern struct {
+    dest_ip: @Vector(4, u8) align(1),
+    src_ip: @Vector(4, u8) align(1),
+    header_checksum: @Vector(2, u8) align(1) = .{ 0, 0 },
+    protocol: u8 align(1) = 0,
+    ttl: u8 align(1) = 0,
+    fragment_and_flags: packed struct(u16) {
+        fragment_offset: u13 = 0,
+        ethernet_flags: u3 = 0,
+    } = .{},
     // fragment_offset: u13 = 0,
-    ttl: u8 = 0,
-    protocol: u8 = 0,
+    // ethernet_flags: u3 = 0,
+    identification: u16 align(1) = 0,
+    total_length: u16 align(1) = 0x04,
+    type_of_service: u8 align(1) = 0,
+    header_and_version: packed struct(u8) {
+        header_length: u4 = 5,
+        ip_version: u4 = 4,
+    } = .{},
+    // header_length: u4 = 5,
+    // ip_version: u4 = 4,
 
-    header_checksum: @Vector(2, u8) = .{ 0, 0 },
-    src_ip: @Vector(4, u8),
-
-    dest_ip: @Vector(4, u8),
-
-    fn write(hdr: @This(), writer: *std.Io.Writer) Writer.Error!usize {
+    fn write(hdr: IpHeaders, writer: *std.Io.Writer) Writer.Error!void {
         try writer.writeInt(u8, 0x45, .big); // ip version and header length
         try writer.writeByte(hdr.type_of_service);
         try writer.writeInt(u16, hdr.total_length, .big);
@@ -132,60 +137,73 @@ const IpHeaders = struct {
         try writer.writeInt(u16, @bitCast(hdr.header_checksum), .big);
         try writer.writeInt(u32, @bitCast(hdr.src_ip), .big);
         try writer.writeInt(u32, @bitCast(hdr.dest_ip), .big);
-        return byte_len;
     }
 
-    const byte_len = blk: {
-        var res: usize = 0;
-        res += @sizeOf(u8);
-        res += @sizeOf(u8);
-        res += @sizeOf(u16);
-        res += @sizeOf(u16);
-        res += @sizeOf(u16);
-        res += @sizeOf(u8);
-        res += @sizeOf(u8);
-        res += @sizeOf(u16);
-        res += @sizeOf(u32);
-        res += @sizeOf(u32);
-        break :blk res;
-    };
-
-    fn bytes(hdr: IpHeaders) [byte_len]u8 {
-        var res: [byte_len]u8 = undefined;
-        hdr.write(Writer.fixed(&res)) catch unreachable;
+    fn bytes(hdr: IpHeaders) [@bitSizeOf(IpHeaders) / 8]u8 {
+        var res: [@bitSizeOf(IpHeaders) / 8]u8 = undefined;
+        var w = Writer.fixed(&res);
+        _ = hdr.write(&w) catch unreachable;
+        return res;
     }
 };
 
+test IpHeaders {
+    var a: IpHeaders = .{
+        .dest_ip = .{ 1, 2, 3, 4 },
+        .src_ip = .{ 5, 6, 7, 8 },
+        // .header_checksum = .{ 0x1, 0x1 },
+        // .protocol = 0,
+        // .ttl = 0x64,
+        // .identification = 3,
+        // .type_of_service = 7,
+    };
+    // a.dest_ip = .{ 1, 2, 3, 4 };
+    // a.src_ip = .{ 5, 6, 7, 8 };
+    std.debug.print("ip struct: {}\n", .{a});
+    std.debug.print("dest ip: {}\n", .{a.dest_ip});
+    std.debug.print("src ip: {}\n", .{a.src_ip});
+
+    std.debug.print("raw b   :  {x}\n", .{@as([@bitSizeOf(IpHeaders) / 8]u8, @bitCast(a))});
+
+    std.debug.print("ip bytes:  {x}\n", .{a.bytes()});
+    var a_struct: [@bitSizeOf(IpHeaders) / 8]u8 = undefined;
+    var a_struct_w = Writer.fixed(&a_struct);
+    _ = a_struct_w.writeStruct(a, .big) catch unreachable;
+    std.debug.print("ip struct: {x}\n", .{a_struct});
+    try std.testing.expectEqual(a, a);
+}
+
 const UdpHeaders = packed struct {
+    checksum: @Vector(2, u8) = .{ 0, 0 },
+    length: u16,
+    dest_port: u16,
     src_port: u16,
 
-    dest_port: u16,
-    length: u16,
-    checksum: @Vector(2, u8) = .{ 0, 0 },
-
-    fn write(hdr: @This(), writer: *std.Io.Writer) Writer.Error!usize {
-        try writer.writeInt(u16, hdr.src_port, .big);
-        try writer.writeInt(u16, hdr.dest_port, .big);
-        try writer.writeInt(u16, hdr.length, .big);
-        try writer.writeInt(u16, @bitCast(hdr.checksum), .big);
-        return byte_len;
+    fn write(hdr: UdpHeaders, writer: *std.Io.Writer) Writer.Error!void {
+        try writer.writeStruct(hdr, .big);
     }
 
-    const byte_len = blk: {
-        var res: usize = 0;
-        res += @sizeOf(u16);
-        res += @sizeOf(u16);
-        res += @sizeOf(u16);
-        res += @sizeOf(u16);
-        break :blk res;
-    };
-
-    fn bytes(hdr: UdpHeaders) [byte_len]u8 {
-        var res: [byte_len]u8 = undefined;
-        hdr.write(Writer.fixed(&res)) catch unreachable;
+    fn bytes(hdr: UdpHeaders) [@sizeOf(UdpHeaders)]u8 {
+        var res: [@sizeOf(UdpHeaders)]u8 = undefined;
+        var w = Writer.fixed(&res);
+        _ = hdr.write(&w) catch unreachable;
+        return res;
     }
 };
 
+test UdpHeaders {
+    const a: UdpHeaders = .{
+        .src_port = 1,
+        .dest_port = 2,
+        .length = 3,
+        .checksum = .{ 0x04, 0x05 },
+    };
+    var a_struct: [@sizeOf(UdpHeaders)]u8 = undefined;
+    var a_struct_w = Writer.fixed(&a_struct);
+    _ = a_struct_w.writeStruct(a, .big) catch unreachable;
+    try std.testing.expectEqual(a.bytes(), a_struct);
+}
+
 const std = @import("std");
 const Random = std.Random;
 const posix = std.posix;

src/message.zig

@@ -196,7 +196,7 @@ test "testing variable length zero copy struct" {
         var msg_bytes: [try Message.calcSize(.relay, payload.len)]u8 align(@alignOf(Message)) = undefined;
 
         // Create a view of the byte slice as a Message
-        const msg: *Message = .init(.relay, &msg_bytes);
+        const msg: *align(1) Message = .init(.relay, &msg_bytes);
 
         {
             // Set the message values
@@ -234,7 +234,7 @@ test "testing variable length zero copy struct" {
         var msg_bytes: [try Message.calcSize(.connection, payload.len)]u8 align(@alignOf(Message)) = undefined;
 
         // Create a view of the byte slice as a Message
-        const msg: *Message = .init(.connection, &msg_bytes);
+        const msg: *align(1) Message = .init(.connection, &msg_bytes);
 
         {
             // Initializing connection header values

src/root.zig

@@ -6,8 +6,11 @@ pub const NetWriter = @import("NetWriter.zig");
 const msg = @import("message.zig");
 
 pub const PacketType = msg.PacketType;
-pub const foo = msg.foo;
 pub const ConnectionOptions = msg.ConnectionOptions;
 pub const MessageTypeError = msg.MessageTypeError;
 pub const MessageParseError = msg.MessageParseError;
 pub const Message = msg.Message;
+
+test {
+    @import("std").testing.refAllDecls(@This());
+}