Write ether headers properly

src/Client.zig

@@ -1,6 +1,8 @@
 const base64Enc = std.base64.Base64Encoder.init(std.base64.standard_alphabet_chars, '=');
 const base64Dec = std.base64.Base64Decoder.init(std.base64.standard_alphabet_chars, '=');
 
+const native_endian = @import("builtin").cpu.arch.endian();
+
 rand: Random,
 writer: *std.Io.Writer,
 
@@ -31,106 +33,78 @@ pub fn deinit(self: *Self) void {
 fn broadcastInitialInterestMessage(self: *Self, msg_bytes: []align(@alignOf(SaprusMessage)) u8) !void {
     const writer = self.writer;
 
-    const UdpHeaders = packed struct {
+    const EthernetHeaders = packed struct {
-        dest_mac: u48, // [6]u8
+        dest_mac: @Vector(6, u8),
 
-        src_mac: u48, // [6]u8
+        src_mac: @Vector(6, u8),
 
         ether_type: u16,
+    };
+
+    const IpHeaders = packed struct {
         ip_version: u4,
-        header_length: u4,
+        header_length: u4 = 0,
-        type_of_service: u8,
+        type_of_service: u8 = 0,
         total_length: u16,
 
-        identification: u16,
+        identification: u16 = 0,
-        ethernet_flags: u3,
+        ethernet_flags: u3 = 0,
-        fragment_offset: u13,
+        fragment_offset: u13 = 0,
-        ttl: u8,
+        ttl: u8 = 0,
-        protocol: u8,
+        protocol: u8 = 0,
 
-        header_checksum: u16, // [2]u8
+        header_checksum: @Vector(2, u8) = .{ 0, 0 },
-        src_ip: u16, // [2]u8
+        src_ip: @Vector(4, u8),
-        dest_ip: u16, // [2]u8
 
-        src_port: u16, // [2]u8
+        dest_ip: @Vector(4, u8),
-        dest_port: u16, // [2]u8
+    };
+
+    const UdpHeaders = packed struct {
+        src_port: @Vector(2, u8),
+
+        dest_port: @Vector(2, u8),
         length: u16,
-
+        checksum: @Vector(2, u8) = .{ 0, 0 },
-        checksum: u16, // [2]u8
-
-        fn init(
-            in: struct {
-                dest_mac: [6]u8,
-                src_mac: [6]u8,
-                ether_type: u16,
-                ip_version: u4,
-                header_length: u4 = 0,
-                type_of_service: u4 = 0,
-                total_length: usize,
-                identification: u16 = 0,
-                ethernet_flags: u3 = 0,
-                fragment_offset: u13 = 0,
-                ttl: u8 = 0,
-                protocol: u8 = 0,
-                header_checksum: [2]u8 = .{ 0, 0 },
-                src_ip: [2]u8,
-                dest_ip: [2]u8,
-                src_port: [2]u8,
-                dest_port: [2]u8,
-                length: usize,
-                checksum: [2]u8 = .{ 0, 0 },
-            },
-        ) @This() {
-            return .{
-                .dest_mac = @bitCast(in.dest_mac),
-                .src_mac = @bitCast(in.src_mac),
-                .ether_type = in.ether_type,
-                .ip_version = in.ip_version,
-                .header_length = in.header_length,
-                .type_of_service = in.type_of_service,
-                .total_length = @intCast(in.total_length),
-                .identification = in.identification,
-                .ethernet_flags = in.ethernet_flags,
-                .fragment_offset = in.fragment_offset,
-                .ttl = in.ttl,
-                .protocol = in.protocol,
-                .header_checksum = @bitCast(in.header_checksum),
-                .src_ip = @bitCast(in.src_ip),
-                .dest_ip = @bitCast(in.dest_ip),
-                .src_port = @bitCast(in.src_port),
-                .dest_port = @bitCast(in.dest_port),
-                .length = @intCast(in.length),
-                .checksum = @bitCast(in.checksum),
-            };
-        }
     };
 
     const total_len = (@bitSizeOf(UdpHeaders) / 8) + msg_bytes.len;
     std.debug.assert(writer.buffer.len >= total_len);
     _ = writer.consumeAll();
 
-    const headers: UdpHeaders = .init(.{
+    var ether_headers: EthernetHeaders = .{
-        .dest_mac = .{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
+        .dest_mac = .{ 0xff, 0xff, 0xff, 0xff, 0xfe, 0xff },
+        // .src_mac = .{ 0xee, 0xee, 0xee, 0xee, 0xee, 0xee },
         .src_mac = blk: {
-            const r_bytes = try writer.writableArray(6);
+            var output_bytes: [6]u8 = undefined;
-            self.rand.bytes(r_bytes);
+            // const r_bytes = try writer.writableArray(6);
-            break :blk r_bytes.*;
+            self.rand.bytes(&output_bytes);
+            break :blk output_bytes;
         },
         .ether_type = 0x0800,
+    };
+
+    const ip_headers: IpHeaders = .{
         .ip_version = 0x4,
         .header_length = 0x5,
-        .total_length = total_len - 8, // 8 is the ethernet frame length (macs + type)
+        .total_length = @intCast(total_len - 8), // 8 is the ethernet frame length (macs + type)
         .protocol = 0x11,
-        .src_ip = .{ 0, 0 },
+        .src_ip = .{ 0, 0, 0, 0 },
-        .dest_ip = .{ 0, 0 },
+        .dest_ip = .{ 0, 0, 0, 0 },
+    };
+
+    const udp_headers: UdpHeaders = .{
         .src_port = .{ 0, 0 },
         .dest_port = .{ 0xb8, 0x22 },
-        .length = msg_bytes.len,
+        .length = @intCast(msg_bytes.len),
-    });
+    };
+    _ = ip_headers;
+    _ = udp_headers;
+    _ = &ether_headers;
 
-    _ = try writer.write(&@as([@bitSizeOf(UdpHeaders) / 8]u8, @bitCast(headers)));
+    // _ = try writer.write(&@as([@bitSizeOf(UdpHeaders) / 8]u8, @bitCast(headers)));
 
-    // try writer.writeStruct(headers, .big);
+    std.mem.byteSwapAllFields(EthernetHeaders, &ether_headers);
+    try writer.writeStruct(ether_headers, native_endian);
 
     // // Ensure buffer is large enough
     // std.debug.assert(writer.buffer.len > 38 + msg_bytes.len);
@@ -190,7 +164,7 @@ fn broadcastInitialInterestMessage(self: *Self, msg_bytes: []align(@alignOf(Sapr
     try msg.networkFromNativeEndian();
     defer msg.nativeFromNetworkEndian() catch unreachable;
 
-    std.debug.print("headers: {x}\n", .{@as([@bitSizeOf(UdpHeaders) / 8]u8, @bitCast(headers))});
+    // std.debug.print("headers: {x}\n", .{@as([@bitSizeOf(UdpHeaders) / 8]u8, @bitCast(headers))});
     std.debug.print("bytes: {x}\n", .{writer.buffer[0..writer.end]});
     _ = try writer.write(msg_bytes);