src/Client.zig

@@ -14,9 +14,10 @@ pub fn deinit() void {
     network.deinit();
 }
 
-fn broadcastSaprusMessage(msg: SaprusMessage, udp_port: u16, allocator: Allocator) !void {
-    const msg_bytes = try msg.toBytes(allocator);
-    defer allocator.free(msg_bytes);
+fn broadcastSaprusMessage(msg: *SaprusMessage, udp_port: u16) !void {
+    const msg_bytes = msg.asBytes();
+    try msg.networkFromNativeEndian();
+    defer msg.nativeFromNetworkEndian() catch unreachable;
 
     var sock = try network.Socket.create(.ipv4, .udp);
     defer sock.close();
@@ -40,14 +41,13 @@ fn broadcastSaprusMessage(msg: SaprusMessage, udp_port: u16, allocator: Allocato
 }
 
 pub fn sendRelay(payload: []const u8, dest: [4]u8, allocator: Allocator) !void {
-    const msg = SaprusMessage{
-        .relay = .{
-            .header = .{ .dest = dest },
-            .payload = payload,
-        },
-    };
+    const msg: *SaprusMessage = try .init(allocator, .relay, @intCast(payload.len));
+    defer msg.deinit(allocator);
+    const relay = (try msg.getSaprusTypePayload()).relay;
+    relay.dest = dest;
+    @memcpy(relay.getPayload(), payload);
 
-    try broadcastSaprusMessage(msg, 8888, allocator);
+    try broadcastSaprusMessage(msg, 8888);
 }
 
 fn randomPort() u16 {
@@ -59,26 +59,25 @@ 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{
-        .connection = .{
-            .header = .{
-                .src_port = initial_port,
-                .dest_port = dest_port,
-            },
-            .payload = payload,
-        },
-    };
+    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);
 
-    try broadcastSaprusMessage(msg, 8888, allocator);
+    try broadcastSaprusMessage(msg, 8888);
 
     return msg;
 }
 
 pub fn connect(payload: []const u8, allocator: Allocator) !?SaprusConnection {
+    if (false) {
         var foo: gcat.nic.RawSocket = try .init("enp7s0"); // /proc/net/dev
         defer foo.deinit();
+    }
 
     var initial_port: u16 = 0;
     if (rand) |r| {
@@ -86,7 +85,7 @@ pub fn connect(payload: []const u8, allocator: Allocator) !?SaprusConnection {
     } 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);
 
     var sock = try network.Socket.create(.ipv4, .udp);
     defer sock.close();
@@ -103,14 +102,15 @@ pub fn connect(payload: []const u8, allocator: Allocator) !?SaprusConnection {
 
     const msg = try sendInitialConnection(payload, initial_port, allocator);
 
-    var response_buf: [4096]u8 = undefined;
+    var response_buf: [4096]u8 align(4) = @splat(0);
     _ = try sock.receive(&response_buf); // Ignore message that I sent.
     const len = try sock.receive(&response_buf);
 
-    initial_conn_res = try SaprusMessage.fromBytes(response_buf[0..len], allocator);
+    std.debug.print("response bytes: {x}\n", .{response_buf});
+    initial_conn_res = (try SaprusMessage.bytesAsValue(response_buf[0..len])).*;
 
     // Complete handshake after awaiting response
-    try broadcastSaprusMessage(msg, randomPort(), allocator);
+    try broadcastSaprusMessage(msg, randomPort());
 
     if (false) {
         return initial_conn_res.?;

src/main.zig

@@ -63,6 +63,7 @@ pub fn main() !void {
             error.WouldBlock => null,
             else => return err,
         };
+        return;
     }
 
     return clap.help(std.io.getStdErr().writer(), clap.Help, &params, .{});

src/message.zig

@@ -31,7 +31,8 @@ pub const Error = error{
 
 // ZERO COPY STUFF
 // &payload could be a void value that is treated as a pointer to a [*]u8
-pub const ZeroCopyMessage = packed struct {
+/// All Saprus messages
+pub const Message = packed struct {
     const Relay = packed struct {
         dest: @Vector(4, u8),
         payload: void,
@@ -55,14 +56,14 @@ pub const ZeroCopyMessage = packed struct {
             return @as([*]u8, @ptrCast(&self.payload))[0 .. len.* - @sizeOf(Connection)];
         }
 
-        fn nativeFromNetworkEndian(self: *align(1) Connection) Error!void {
+        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) Error!void {
+        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);
@@ -81,7 +82,8 @@ pub const ZeroCopyMessage = packed struct {
         const header_size = @sizeOf(switch (@"type") {
             .relay => Relay,
             .connection => Connection,
-            else => return error.Bad,
+            .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);
@@ -121,9 +123,17 @@ pub const ZeroCopyMessage = packed struct {
             @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| try con.*.nativeFromNetworkEndian(),
+            .connection => |*con| con.*.nativeFromNetworkEndian(),
             // We know other values are unreachable,
             // because they would have returned an error from the switch condition.
             else => unreachable,
@@ -166,179 +176,42 @@ 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 ZeroCopyMessage
-    const zcm: *ZeroCopyMessage = try .init(gpa, .relay, payload.len);
-    defer zcm.deinit(gpa);
+    // 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.
-            // zcm.type = .relay;
-            // zcm.length = payload_len;
+            // msg.type = .relay;
+            // msg.length = payload_len;
         }
-        const relay = (try zcm.getSaprusTypePayload()).relay;
+        const relay = (try msg.getSaprusTypePayload()).relay;
         relay.dest = .{ 1, 2, 3, 4 };
         @memcpy(relay.getPayload(), payload);
     }
 
     {
-        const bytes = zcm.asBytes();
+        const bytes = msg.asBytes();
 
         // Print the message as hex using the network byte order
-        try zcm.networkFromNativeEndian();
+        try msg.networkFromNativeEndian();
         // We know the error from nativeFromNetworkEndian is unreachable because
         // it would have returned an error from networkFromNativeEndian.
-        defer zcm.nativeFromNetworkEndian() catch unreachable;
+        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 zcm.getSaprusTypePayload()).connection});
+        std.debug.print("{any}\n", .{(try msg.getSaprusTypePayload()).connection});
     }
 
-    try std.testing.expectEqualDeep(zcm, try ZeroCopyMessage.bytesAsValue(zcm.asBytes()));
+    try std.testing.expectEqualDeep(msg, try Message.bytesAsValue(msg.asBytes()));
 }
 
-/// All Saprus messages
-pub const Message = union(PacketType) {
-    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: ConnectionOptions = .{},
-        };
-        header: Header,
-        payload: []const u8,
-    };
-    relay: Relay,
-    file_transfer: void, // unimplemented
-    connection: Connection,
-
-    /// Should be called for any Message that was declared using a function that you pass an allocator to.
-    pub fn deinit(self: Message, 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: Message, 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 Error.NotImplementedSaprusType,
-        }
-
-        // Collect the growable list as a slice and return it.
-        return buf.toOwnedSlice();
-    }
-
-    fn fromBytesAux(
-        comptime packet: PacketType,
-        len: u16,
-        r: std.io.FixedBufferStream([]const u8).Reader,
-        allocator: Allocator,
-    ) !Message {
-        const Header = @field(@FieldType(Message, @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 Message specified by the `packet` argument.
-        return @unionInit(Message, @tagName(packet), .{
-            .header = header,
-            .payload = payload,
-        });
-    }
-
-    /// Caller is responsible for calling .deinit on the returned value.
-    pub fn fromBytes(bytes: []const u8, allocator: Allocator) !Message {
-        var s = std.io.fixedBufferStream(bytes);
-        const r = s.reader();
-
-        // Read packet type
-        const packet_type = @as(PacketType, @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 Error.NotImplementedSaprusType,
-            else => return Error.UnknownSaprusType,
-        }
-    }
-};
-
 const std = @import("std");
 const Allocator = std.mem.Allocator;