Need to flush io in release mode

build.zig

@@ -15,12 +15,6 @@ pub fn build(b: *std.Build) void {
     // set a preferred release mode, allowing the user to decide how to optimize.
     const optimize = b.standardOptimizeOption(.{});
 
-    const lib_mod = b.createModule(.{
-        .root_source_file = b.path("src/root.zig"),
-        .target = target,
-        .optimize = optimize,
-    });
-
     // We will also create a module for our other entry point, 'main.zig'.
     const exe_mod = b.createModule(.{
         // `root_source_file` is the Zig "entry point" of the module. If a module
@@ -32,20 +26,9 @@ pub fn build(b: *std.Build) void {
         .optimize = optimize,
     });
 
-    lib_mod.addImport("network", b.dependency("network", .{}).module("network"));
-    lib_mod.addImport("gatorcat", b.dependency("gatorcat", .{}).module("gatorcat"));
-
-    exe_mod.addImport("zaprus", lib_mod);
+    exe_mod.addImport("network", b.dependency("network", .{}).module("network"));
     exe_mod.addImport("clap", b.dependency("clap", .{}).module("clap"));
 
-    const lib = b.addLibrary(.{
-        .linkage = .static,
-        .name = "zaprus",
-        .root_module = lib_mod,
-    });
-
-    b.installArtifact(lib);
-
     // This creates another `std.Build.Step.Compile`, but this one builds an executable
     // rather than a static library.
     const exe = b.addExecutable(.{

build.zig.zon

@@ -44,10 +44,6 @@
             .url = "git+https://github.com/Hejsil/zig-clap?ref=0.10.0#e47028deaefc2fb396d3d9e9f7bd776ae0b2a43a",
             .hash = "clap-0.10.0-oBajB434AQBDh-Ei3YtoKIRxZacVPF1iSwp3IX_ZB8f0",
         },
-        .gatorcat = .{
-            .url = "git+https://github.com/kj4tmp/gatorcat#bb1847f6c95852e7a0ec8c07870a948c171d5f98",
-            .hash = "gatorcat-0.3.2-WcrpTf1mBwDrmPaIhKCfLJO064v8Sjjn7DBq4CKZSgHH",
-        },
     },
     .paths = .{
         "build.zig",

src/main.zig

@@ -23,7 +23,6 @@ pub fn main() !void {
     const params = comptime clap.parseParamsComptime(
         \\-h, --help           Display this help and exit.
         \\-r, --relay <str>    A relay message to send.
-        \\-d, --dest <str>     An IPv4 or <= 4 ASCII byte string.
         \\-c, --connect <str>  A connection message to send.
         \\
     );
@@ -42,54 +41,42 @@ pub fn main() !void {
     };
     defer res.deinit();
 
-    try SaprusClient.init();
-    defer SaprusClient.deinit();
+    try Saprus.init();
+    defer Saprus.deinit();
 
     if (res.args.help != 0) {
         return clap.help(std.io.getStdErr().writer(), clap.Help, &params, .{});
     }
 
+    std.debug.print("main\n", .{});
+
     if (res.args.relay) |r| {
-        const dest = parseDest(res.args.dest);
-        try SaprusClient.sendRelay(
-            if (r.len > 0) r else "Hello darkness my old friend",
-            dest,
-            gpa,
-        );
-        // std.debug.print("Sent: {s}\n", .{r});
+        try Saprus.sendRelay(if (r.len > 0) r else "Hello darkness my old friend", gpa);
+        std.debug.print("Sent: {s}\n", .{r});
         return;
     } else if (res.args.connect) |c| {
-        _ = SaprusClient.connect(if (c.len > 0) c else "Hello darkness my old friend", gpa) catch |err| switch (err) {
+        const conn_res: ?SaprusMessage = Saprus.connect(if (c.len > 0) c else "Hello darkness my old friend", gpa) catch |err| switch (err) {
             error.WouldBlock => null,
             else => return err,
         };
+        defer if (conn_res) |r| r.deinit(gpa);
+        if (conn_res) |r| {
+            std.debug.print("{s}\n", .{r.connection.payload});
+        } else {
+            std.debug.print("No response from connection request\n", .{});
+        }
         return;
     }
 
     return clap.help(std.io.getStdErr().writer(), clap.Help, &params, .{});
 }
 
-fn parseDest(in: ?[]const u8) [4]u8 {
-    if (in) |dest| {
-        if (dest.len <= 4) {
-            var res: [4]u8 = @splat(0);
-            @memcpy(res[0..dest.len], dest);
-            return res;
-        }
-
-        const addr = std.net.Ip4Address.parse(dest, 0) catch return "FAIL".*;
-        return @bitCast(addr.sa.addr);
-    }
-    return "zap\x00".*;
-}
-
 const builtin = @import("builtin");
 const std = @import("std");
 const DebugAllocator = std.heap.DebugAllocator(.{});
 const ArrayList = std.ArrayList;
 
-const zaprus = @import("zaprus");
-const SaprusClient = zaprus.Client;
-const SaprusMessage = zaprus.Message;
+const Saprus = @import("./saprus.zig");
+const SaprusMessage = Saprus.SaprusMessage;
 
 const clap = @import("clap");

src/message.zig

@@ -1,339 +0,0 @@
-/// Type tag for Message union.
-/// This is the first value in the actual packet sent over the network.
-pub const PacketType = enum(u16) {
-    relay = 0x003C,
-    file_transfer = 0x8888,
-    connection = 0x00E9,
-    _,
-};
-
-/// Reserved option values.
-/// Currently unused.
-pub const ConnectionOptions = packed struct(u8) {
-    opt1: bool = false,
-    opt2: bool = false,
-    opt3: bool = false,
-    opt4: bool = false,
-    opt5: bool = false,
-    opt6: bool = false,
-    opt7: bool = false,
-    opt8: bool = false,
-};
-
-pub const Error = error{
-    NotImplementedSaprusType,
-    UnknownSaprusType,
-    InvalidMessage,
-};
-
-pub fn MessageNew(comptime packet_type: PacketType) type {
-    comptime {
-        if (packet_type == .file_transfer)
-            @compileError("File transfer not implemented");
-        if (packet_type != .relay and packet_type != .connection)
-            @compileError("Unkown message type");
-    }
-
-    return packed struct {
-        const Self = @This();
-        const SelfBytes = []align(@alignOf(Self)) u8;
-
-        const Relay = struct {
-            pub fn getPayload(self: *Self) []u8 {
-                return @as([*]align(@alignOf(Self)) u8, @ptrCast(&self.payload))[0 .. self.length - 4];
-            }
-        };
-        const Connection = packed struct {
-            pub fn getPayload(self: Self) []u8 {
-                return @as([*]u8, &self.payload)[0 .. self.length - 4];
-            }
-        };
-
-        type: PacketType = packet_type,
-        length: u16,
-
-        // Relay
-        dest: if (packet_type == .relay) @Vector(4, u8) else void,
-
-        // Connection
-        src_port: if (packet_type == .connection) u16 else void, // random number > 1024
-        dest_port: if (packet_type == .connection) u16 else void, // random number > 1024
-        seq_num: if (packet_type == .connection) u32 else void,
-        msg_id: if (packet_type == .connection) u32 else void,
-        reserved: if (packet_type == .connection) u8 else void,
-        options: if (packet_type == .connection) ConnectionOptions else void = if (packet_type == .connection) .{} else {},
-
-        // Relay or Connection
-        payload: switch (packet_type) {
-            .relay, .connection => void,
-            else => noreturn,
-        },
-
-        pub usingnamespace switch (packet_type) {
-            .relay => Relay,
-            .connection => Connection,
-            .file_transfer => @compileError("File Transfer message type not implemented"),
-            else => @compileError("Unknown message type"),
-        };
-
-        pub fn init(allocator: Allocator, payload_len: u16) !*Self {
-            const size = payload_len + @sizeOf(Self);
-            const bytes = try allocator.alignedAlloc(u8, @alignOf(Self), size);
-            const res: *Self = @ptrCast(bytes.ptr);
-            res.type = packet_type;
-            res.length = payload_len;
-            return res;
-        }
-
-        pub fn deinit(self: *Self, allocator: Allocator) void {
-            allocator.free(self.asBytes());
-        }
-
-        pub fn nativeFromNetworkEndian(self: *Self) void {
-            self.type = @enumFromInt(bigToNative(
-                @typeInfo(@TypeOf(self.type)).@"enum".tag_type,
-                @intFromEnum(self.type),
-            ));
-            self.length = bigToNative(@TypeOf(self.length), self.length);
-
-            if (packet_type == .connection) {
-                self.src_port = bigToNative(@TypeOf(self.src_port), self.src_port);
-                self.dest_port = bigToNative(@TypeOf(self.dest_port), self.dest_port);
-                self.seq_num = bigToNative(@TypeOf(self.seq_num), self.seq_num);
-                self.msg_id = bigToNative(@TypeOf(self.msg_id), self.msg_id);
-            }
-        }
-
-        pub fn networkFromNativeEndian(self: *Self) void {
-            self.type = @enumFromInt(bigToNative(
-                @typeInfo(@TypeOf(self.type)).@"enum".tag_type,
-                @intFromEnum(self.type),
-            ));
-            self.length = bigToNative(@TypeOf(self.length), self.length);
-
-            if (packet_type == .connection) {
-                self.src_port = nativeToBig(@TypeOf(self.src_port), self.src_port);
-                self.dest_port = nativeToBig(@TypeOf(self.dest_port), self.dest_port);
-                self.seq_num = nativeToBig(@TypeOf(self.seq_num), self.seq_num);
-                self.msg_id = nativeToBig(@TypeOf(self.msg_id), self.msg_id);
-            }
-        }
-
-        pub fn asBytes(self: *Self) SelfBytes {
-            const size = @sizeOf(Self) + self.length;
-            return @as([*]align(@alignOf(Self)) u8, @ptrCast(self))[0..size];
-        }
-    };
-}
-
-test MessageNew {
-    comptime for (@typeInfo(MessageNew(.connection)).@"struct".decls) |field| {
-        @compileLog(field);
-    };
-}
-
-// pub fn bytesAsMessage(bytes: []const u8) !*Self {
-//     const res = std.mem.bytesAsValue(Self, bytes);
-//     return switch (res.type) {
-//         .relay, .connection => if (bytes.len == res.length + @sizeOf(Self))
-//             res
-//         else
-//             Error.InvalidMessage,
-//         .file_transfer => Error.NotImplementedSaprusType,
-//         else => Error.UnknownSaprusType,
-//     };
-// }
-
-// ZERO COPY STUFF
-// &payload could be a void value that is treated as a pointer to a [*]u8
-/// All Saprus messages
-pub const Message = packed struct {
-    const Relay = packed struct {
-        dest: @Vector(4, u8),
-        payload: void,
-
-        pub fn getPayload(self: *align(1) Relay) []u8 {
-            const len: *u16 = @ptrFromInt(@intFromPtr(self) - @sizeOf(u16));
-            return @as([*]u8, @ptrCast(&self.payload))[0 .. len.* - @sizeOf(Relay)];
-        }
-    };
-    const Connection = packed struct {
-        src_port: u16, // random number > 1024
-        dest_port: u16, // random number > 1024
-        seq_num: u32 = 0,
-        msg_id: u32 = 0,
-        reserved: u8 = 0,
-        options: ConnectionOptions = .{},
-        payload: void,
-
-        pub fn getPayload(self: *align(1) Connection) []u8 {
-            const len: *u16 = @ptrFromInt(@intFromPtr(self) - @sizeOf(u16));
-            return @as([*]u8, @ptrCast(&self.payload))[0 .. len.* - @sizeOf(Connection)];
-        }
-
-        fn nativeFromNetworkEndian(self: *align(1) Connection) void {
-            self.src_port = bigToNative(@TypeOf(self.src_port), self.src_port);
-            self.dest_port = bigToNative(@TypeOf(self.dest_port), self.dest_port);
-            self.seq_num = bigToNative(@TypeOf(self.seq_num), self.seq_num);
-            self.msg_id = bigToNative(@TypeOf(self.msg_id), self.msg_id);
-        }
-
-        fn networkFromNativeEndian(self: *align(1) Connection) void {
-            self.src_port = nativeToBig(@TypeOf(self.src_port), self.src_port);
-            self.dest_port = nativeToBig(@TypeOf(self.dest_port), self.dest_port);
-            self.seq_num = nativeToBig(@TypeOf(self.seq_num), self.seq_num);
-            self.msg_id = nativeToBig(@TypeOf(self.msg_id), self.msg_id);
-        }
-    };
-
-    const Self = @This();
-    const SelfBytes = []align(@alignOf(Self)) u8;
-
-    type: PacketType,
-    length: u16,
-    bytes: void = {},
-
-    pub fn init(allocator: Allocator, comptime @"type": PacketType, payload_len: u16) !*Self {
-        const header_size = @sizeOf(switch (@"type") {
-            .relay => Relay,
-            .connection => Connection,
-            .file_transfer => return Error.NotImplementedSaprusType,
-            else => return Error.UnknownSaprusType,
-        });
-        const size = payload_len + @sizeOf(Self) + header_size;
-        const bytes = try allocator.alignedAlloc(u8, @alignOf(Self), size);
-        const res: *Self = @ptrCast(bytes.ptr);
-        res.type = @"type";
-        res.length = payload_len + header_size;
-        return res;
-    }
-
-    pub fn deinit(self: *Self, allocator: Allocator) void {
-        allocator.free(self.asBytes());
-    }
-
-    fn getRelay(self: *Self) *align(1) Relay {
-        return std.mem.bytesAsValue(Relay, &self.bytes);
-    }
-    fn getConnection(self: *Self) *align(1) Connection {
-        return std.mem.bytesAsValue(Connection, &self.bytes);
-    }
-
-    pub fn getSaprusTypePayload(self: *Self) Error!(union(PacketType) {
-        relay: *align(1) Relay,
-        file_transfer: void,
-        connection: *align(1) Connection,
-    }) {
-        return switch (self.type) {
-            .relay => .{ .relay = self.getRelay() },
-            .connection => .{ .connection = self.getConnection() },
-            .file_transfer => Error.NotImplementedSaprusType,
-            else => Error.UnknownSaprusType,
-        };
-    }
-
-    pub fn nativeFromNetworkEndian(self: *Self) Error!void {
-        self.type = @enumFromInt(bigToNative(
-            @typeInfo(@TypeOf(self.type)).@"enum".tag_type,
-            @intFromEnum(self.type),
-        ));
-        self.length = bigToNative(@TypeOf(self.length), self.length);
-        errdefer {
-            // If the payload specific headers fail, revert the top level header values
-            self.type = @enumFromInt(nativeToBig(
-                @typeInfo(@TypeOf(self.type)).@"enum".tag_type,
-                @intFromEnum(self.type),
-            ));
-            self.length = nativeToBig(@TypeOf(self.length), self.length);
-        }
-        switch (try self.getSaprusTypePayload()) {
-            .relay => {},
-            .connection => |*con| con.*.nativeFromNetworkEndian(),
-            // We know other values are unreachable,
-            // because they would have returned an error from the switch condition.
-            else => unreachable,
-        }
-    }
-
-    pub fn networkFromNativeEndian(self: *Self) Error!void {
-        try switch (try self.getSaprusTypePayload()) {
-            .relay => {},
-            .connection => |*con| con.*.networkFromNativeEndian(),
-            .file_transfer => Error.NotImplementedSaprusType,
-            else => Error.UnknownSaprusType,
-        };
-        self.type = @enumFromInt(nativeToBig(
-            @typeInfo(@TypeOf(self.type)).@"enum".tag_type,
-            @intFromEnum(self.type),
-        ));
-        self.length = nativeToBig(@TypeOf(self.length), self.length);
-    }
-
-    pub fn bytesAsValue(bytes: SelfBytes) !*Self {
-        const res = std.mem.bytesAsValue(Self, bytes);
-        return switch (res.type) {
-            .relay, .connection => if (bytes.len == res.length + @sizeOf(Self))
-                res
-            else
-                Error.InvalidMessage,
-            .file_transfer => Error.NotImplementedSaprusType,
-            else => Error.UnknownSaprusType,
-        };
-    }
-
-    pub fn asBytes(self: *Self) SelfBytes {
-        const size = @sizeOf(Self) + self.length;
-        return @as([*]align(@alignOf(Self)) u8, @ptrCast(self))[0..size];
-    }
-};
-
-test "testing variable length zero copy struct" {
-    const gpa = std.testing.allocator;
-    const payload = "Hello darkness my old friend";
-
-    // Create a view of the byte slice as a Message
-    const msg: *Message = try .init(gpa, .relay, payload.len);
-    defer msg.deinit(gpa);
-
-    {
-        // Set the message values
-        {
-            // These are both set by the init call.
-            // msg.type = .relay;
-            // msg.length = payload_len;
-        }
-        const relay = (try msg.getSaprusTypePayload()).relay;
-        relay.dest = .{ 1, 2, 3, 4 };
-        @memcpy(relay.getPayload(), payload);
-    }
-
-    {
-        const bytes = msg.asBytes();
-
-        // Print the message as hex using the network byte order
-        try msg.networkFromNativeEndian();
-        // We know the error from nativeFromNetworkEndian is unreachable because
-        // it would have returned an error from networkFromNativeEndian.
-        defer msg.nativeFromNetworkEndian() catch unreachable;
-        std.debug.print("network bytes: {x}\n", .{bytes});
-        std.debug.print("bytes len: {d}\n", .{bytes.len});
-    }
-
-    if (false) {
-        // Illegal behavior
-        std.debug.print("{any}\n", .{(try msg.getSaprusTypePayload()).connection});
-    }
-
-    try std.testing.expectEqualDeep(msg, try Message.bytesAsValue(msg.asBytes()));
-}
-
-const std = @import("std");
-const Allocator = std.mem.Allocator;
-
-const asBytes = std.mem.asBytes;
-const nativeToBig = std.mem.nativeToBig;
-const bigToNative = std.mem.bigToNative;
-
-test {
-    std.testing.refAllDeclsRecursive(@This());
-}

src/root.zig

@@ -1,4 +0,0 @@
-pub const Client = @import("Client.zig");
-pub const Connection = @import("Connection.zig");
-
-pub usingnamespace @import("message.zig");

src/saprus.zig

@@ -1,6 +1,3 @@
-const base64Enc = std.base64.Base64Encoder.init(std.base64.standard_alphabet_chars, '=');
-const base64Dec = std.base64.Base64Decoder.init(std.base64.standard_alphabet_chars, '=');
-
 var rand: ?Random = null;
 
 pub fn init() !void {
@@ -17,14 +14,9 @@ pub fn deinit() void {
     network.deinit();
 }
 
-fn broadcastSaprusMessage(msg: *SaprusMessage, udp_port: u16) !void {
-    if (false) {
-        var foo: gcat.nic.RawSocket = try .init("enp7s0"); // /proc/net/dev
-        defer foo.deinit();
-    }
-    const msg_bytes = msg.asBytes();
-    try msg.networkFromNativeEndian();
-    defer msg.nativeFromNetworkEndian() catch unreachable;
+fn broadcastSaprusMessage(msg: SaprusMessage, udp_port: u16, allocator: Allocator) !void {
+    const msg_bytes = try msg.toBytes(allocator);
+    defer allocator.free(msg_bytes);
 
     var sock = try network.Socket.create(.ipv4, .udp);
     defer sock.close();
@@ -47,16 +39,15 @@ fn broadcastSaprusMessage(msg: *SaprusMessage, udp_port: u16) !void {
     _ = try sock.sendTo(dest_addr, msg_bytes);
 }
 
-pub fn sendRelay(payload: []const u8, dest: [4]u8, allocator: Allocator) !void {
-    const msg: *SaprusMessageNew(.relay) = try .init(
-        allocator,
-        @intCast(base64Enc.calcSize(payload.len)),
-    );
-    defer msg.deinit(allocator);
-    msg.dest = dest;
-    _ = base64Enc.encode(msg.getPayload(), payload);
+pub fn sendRelay(payload: []const u8, allocator: Allocator) !void {
+    const msg = SaprusMessage{
+        .relay = .{
+            .header = .{ .dest = .{ 255, 255, 255, 255 } },
+            .payload = payload,
+        },
+    };
 
-    try broadcastSaprusMessage(try SaprusMessage.bytesAsValue(msg.asBytes()), 8888);
+    try broadcastSaprusMessage(msg, 8888, allocator);
 }
 
 fn randomPort() u16 {
@@ -68,32 +59,37 @@ fn randomPort() u16 {
     return p;
 }
 
-pub fn sendInitialConnection(payload: []const u8, initial_port: u16, allocator: Allocator) !*SaprusMessage {
+pub fn sendInitialConnection(payload: []const u8, initial_port: u16, allocator: Allocator) !SaprusMessage {
     const dest_port = randomPort();
-    const msg: *SaprusMessage = try .init(allocator, .connection, @intCast(payload.len));
-    defer msg.deinit(allocator);
-    const connection = (try msg.getSaprusTypePayload()).connection;
-    connection.src_port = initial_port;
-    connection.dest_port = dest_port;
-    @memcpy(connection.getPayload(), payload);
+    const msg = SaprusMessage{
+        .connection = .{
+            .header = .{
+                .src_port = initial_port,
+                .dest_port = dest_port,
+            },
+            .payload = payload,
+        },
+    };
 
-    try broadcastSaprusMessage(msg, 8888);
+    try broadcastSaprusMessage(msg, 8888, allocator);
 
     return msg;
 }
 
-pub fn connect(payload: []const u8, allocator: Allocator) !?SaprusConnection {
+pub fn connect(payload: []const u8, allocator: Allocator) !?SaprusMessage {
     var initial_port: u16 = 0;
     if (rand) |r| {
         initial_port = r.intRangeAtMost(u16, 1024, 65000);
     } else unreachable;
 
     var initial_conn_res: ?SaprusMessage = null;
-    errdefer if (initial_conn_res) |*c| c.deinit(allocator);
+    errdefer if (initial_conn_res) |c| c.deinit(allocator);
 
+    std.debug.print("creating socket\n", .{});
     var sock = try network.Socket.create(.ipv4, .udp);
     defer sock.close();
 
+    std.debug.print("creating endpoint\n", .{});
     // Bind to 255.255.255.255:8888
     const bind_addr = network.EndPoint{
         .address = network.Address{ .ipv4 = network.Address.IPv4.broadcast },
@@ -102,29 +98,25 @@ pub fn connect(payload: []const u8, allocator: Allocator) !?SaprusConnection {
 
     // timeout 1s
     try sock.setReadTimeout(1 * std.time.us_per_s);
+    std.debug.print("binding to socket\n", .{});
     try sock.bind(bind_addr);
 
+    std.debug.print("sending initial connection payload\n", .{});
     const msg = try sendInitialConnection(payload, initial_port, allocator);
 
-    var response_buf: [4096]u8 align(4) = @splat(0);
+    var response_buf: [4096]u8 = undefined;
     _ = try sock.receive(&response_buf); // Ignore message that I sent.
     const len = try sock.receive(&response_buf);
 
-    std.debug.print("response bytes: {x}\n", .{response_buf});
-    initial_conn_res = (try SaprusMessage.bytesAsValue(response_buf[0..len])).*;
+    initial_conn_res = try SaprusMessage.fromBytes(response_buf[0..len], allocator);
 
     // Complete handshake after awaiting response
-    try broadcastSaprusMessage(msg, randomPort());
+    try broadcastSaprusMessage(msg, randomPort(), allocator);
 
-    if (false) {
-        return initial_conn_res.?;
-    }
-    return null;
+    return initial_conn_res;
 }
 
-const SaprusMessage = @import("message.zig").Message;
-const SaprusMessageNew = @import("message.zig").MessageNew;
-const SaprusConnection = @import("Connection.zig");
+pub const SaprusMessage = @import("./saprus_message.zig").SaprusMessage;
 
 const std = @import("std");
 const Random = std.Random;
@@ -132,6 +124,5 @@ const posix = std.posix;
 const mem = std.mem;
 
 const network = @import("network");
-const gcat = @import("gatorcat");
 
 const Allocator = mem.Allocator;

src/saprus_message.zig

@@ -0,0 +1,211 @@
+const base64Enc = std.base64.Base64Encoder.init(std.base64.standard_alphabet_chars, '=');
+const base64Dec = std.base64.Base64Decoder.init(std.base64.standard_alphabet_chars, '=');
+
+/// Type tag for SaprusMessage union.
+/// This is the first value in the actual packet sent over the network.
+pub const SaprusPacketType = enum(u16) {
+    relay = 0x003C,
+    file_transfer = 0x8888,
+    connection = 0x00E9,
+    _,
+};
+
+/// Reserved option values.
+/// Currently unused.
+pub const SaprusConnectionOptions = packed struct(u8) {
+    opt1: bool = false,
+    opt2: bool = false,
+    opt3: bool = false,
+    opt4: bool = false,
+    opt5: bool = false,
+    opt6: bool = false,
+    opt7: bool = false,
+    opt8: bool = false,
+};
+
+pub const SaprusError = error{
+    NotImplementedSaprusType,
+    UnknownSaprusType,
+};
+
+/// All Saprus messages
+pub const SaprusMessage = union(SaprusPacketType) {
+    pub const Relay = struct {
+        pub const Header = packed struct {
+            dest: @Vector(4, u8),
+        };
+        header: Header,
+        payload: []const u8,
+    };
+    pub const Connection = struct {
+        pub const Header = packed struct {
+            src_port: u16, // random number > 1024
+            dest_port: u16, // random number > 1024
+            seq_num: u32 = 0,
+            msg_id: u32 = 0,
+            reserved: u8 = 0,
+            options: SaprusConnectionOptions = .{},
+        };
+        header: Header,
+        payload: []const u8,
+    };
+    relay: Relay,
+    file_transfer: void, // unimplemented
+    connection: Connection,
+
+    /// Should be called for any SaprusMessage that was declared using a function that you pass an allocator to.
+    pub fn deinit(self: SaprusMessage, allocator: Allocator) void {
+        switch (self) {
+            .relay => |r| allocator.free(r.payload),
+            .connection => |c| allocator.free(c.payload),
+            else => unreachable,
+        }
+    }
+
+    fn toBytesAux(
+        header: anytype,
+        payload: []const u8,
+        buf: *std.ArrayList(u8),
+        allocator: Allocator,
+    ) !void {
+        const Header = @TypeOf(header);
+        // Create a growable string to store the base64 bytes in.
+        // Doing this first so I can use the length of the encoded bytes for the length field.
+        var payload_list = std.ArrayList(u8).init(allocator);
+        defer payload_list.deinit();
+        const buf_w = payload_list.writer();
+
+        // Write the payload bytes as base64 to the growable string.
+        try base64Enc.encodeWriter(buf_w, payload);
+
+        // At this point, payload_list contains the base64 encoded payload.
+
+        // Add the payload length to the output buf.
+        try buf.*.appendSlice(
+            asBytes(&nativeToBig(u16, @intCast(payload_list.items.len + @bitSizeOf(Header) / 8))),
+        );
+
+        // Add the header bytes to the output buf.
+        var header_buf: [@sizeOf(Header)]u8 = undefined;
+        var header_buf_stream = std.io.fixedBufferStream(&header_buf);
+        try header_buf_stream.writer().writeStructEndian(header, .big);
+        // Add the exact number of bits in the header without padding.
+        try buf.*.appendSlice(header_buf[0 .. @bitSizeOf(Header) / 8]);
+
+        try buf.*.appendSlice(payload_list.items);
+    }
+
+    /// Caller is responsible for freeing the returned bytes.
+    pub fn toBytes(self: SaprusMessage, allocator: Allocator) ![]u8 {
+        // Create a growable list of bytes to store the output in.
+        var buf = std.ArrayList(u8).init(allocator);
+        errdefer buf.deinit();
+
+        // Start with writing the message type, which is the first 16 bits of every Saprus message.
+        try buf.appendSlice(asBytes(&nativeToBig(u16, @intFromEnum(self))));
+
+        // Write the proper header and payload for the given packet type.
+        switch (self) {
+            .relay => |r| try toBytesAux(r.header, r.payload, &buf, allocator),
+            .connection => |c| try toBytesAux(c.header, c.payload, &buf, allocator),
+            .file_transfer => return SaprusError.NotImplementedSaprusType,
+        }
+
+        // Collect the growable list as a slice and return it.
+        return buf.toOwnedSlice();
+    }
+
+    fn fromBytesAux(
+        comptime packet: SaprusPacketType,
+        len: u16,
+        r: std.io.FixedBufferStream([]const u8).Reader,
+        allocator: Allocator,
+    ) !SaprusMessage {
+        const Header = @field(@FieldType(SaprusMessage, @tagName(packet)), "Header");
+
+        // Read the header for the current message type.
+        var header_bytes: [@sizeOf(Header)]u8 = undefined;
+        _ = try r.read(header_bytes[0 .. @bitSizeOf(Header) / 8]);
+        var header_stream = std.io.fixedBufferStream(&header_bytes);
+        const header = try header_stream.reader().readStructEndian(Header, .big);
+
+        // Read the base64 bytes into a list to be able to call the decoder on it.
+        const payload_buf = try allocator.alloc(u8, len - @bitSizeOf(Header) / 8);
+        defer allocator.free(payload_buf);
+        _ = try r.readAll(payload_buf);
+
+        // Create a buffer to store the payload in, and decode the base64 bytes into the payload field.
+        const payload = try allocator.alloc(u8, try base64Dec.calcSizeForSlice(payload_buf));
+        try base64Dec.decode(payload, payload_buf);
+
+        // Return the type of SaprusMessage specified by the `packet` argument.
+        return @unionInit(SaprusMessage, @tagName(packet), .{
+            .header = header,
+            .payload = payload,
+        });
+    }
+
+    /// Caller is responsible for calling .deinit on the returned value.
+    pub fn fromBytes(bytes: []const u8, allocator: Allocator) !SaprusMessage {
+        var s = std.io.fixedBufferStream(bytes);
+        const r = s.reader();
+
+        // Read packet type
+        const packet_type = @as(SaprusPacketType, @enumFromInt(try r.readInt(u16, .big)));
+
+        // Read the length of the header + base64 encoded payload.
+        const len = try r.readInt(u16, .big);
+
+        switch (packet_type) {
+            .relay => return fromBytesAux(.relay, len, r, allocator),
+            .connection => return fromBytesAux(.connection, len, r, allocator),
+            .file_transfer => return SaprusError.NotImplementedSaprusType,
+            else => return SaprusError.UnknownSaprusType,
+        }
+    }
+};
+
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+
+const asBytes = std.mem.asBytes;
+const nativeToBig = std.mem.nativeToBig;
+
+test "Round trip Relay toBytes and fromBytes" {
+    const gpa = std.testing.allocator;
+    const msg = SaprusMessage{
+        .relay = .{
+            .header = .{ .dest = .{ 255, 255, 255, 255 } },
+            .payload = "Hello darkness my old friend",
+        },
+    };
+
+    const to_bytes = try msg.toBytes(gpa);
+    defer gpa.free(to_bytes);
+
+    const from_bytes = try SaprusMessage.fromBytes(to_bytes, gpa);
+    defer from_bytes.deinit(gpa);
+
+    try std.testing.expectEqualDeep(msg, from_bytes);
+}
+
+test "Round trip Connection toBytes and fromBytes" {
+    const gpa = std.testing.allocator;
+    const msg = SaprusMessage{
+        .connection = .{
+            .header = .{
+                .src_port = 0,
+                .dest_port = 0,
+            },
+            .payload = "Hello darkness my old friend",
+        },
+    };
+
+    const to_bytes = try msg.toBytes(gpa);
+    defer gpa.free(to_bytes);
+
+    const from_bytes = try SaprusMessage.fromBytes(to_bytes, gpa);
+    defer from_bytes.deinit(gpa);
+
+    try std.testing.expectEqualDeep(msg, from_bytes);
+}