Fix extra bytes in connection message.

src/message.zig

@@ -38,7 +38,7 @@ pub const Message = packed struct {
 
         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)];
+            return @as([*]u8, @ptrCast(&self.payload))[0 .. len.* - @bitSizeOf(Relay) / 8];
         }
     };
     const Connection = packed struct {
@@ -52,7 +52,7 @@ pub const Message = packed struct {
 
         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)];
+            return @as([*]u8, @ptrCast(&self.payload))[0 .. len.* - @bitSizeOf(Connection) / 8];
         }
 
         fn nativeFromNetworkEndian(self: *align(1) Connection) void {
@@ -91,13 +91,12 @@ pub const Message = packed struct {
 
     /// Compute the number of bytes required to store a given payload size for a given message type.
     pub fn calcSize(comptime @"type": PacketType, payload_len: usize) MessageTypeError!u16 {
-        std.debug.assert(payload_len < std.math.maxInt(u16));
+        const header_size = @bitSizeOf(switch (@"type") {
-        const header_size = @sizeOf(switch (@"type") {
             .relay => Relay,
             .connection => Connection,
             .file_transfer => return MessageTypeError.NotImplementedSaprusType,
             else => return MessageTypeError.UnknownSaprusType,
-        });
+        }) / 8;
         return @intCast(payload_len + @sizeOf(Self) + header_size);
     }
 
@@ -191,6 +190,8 @@ pub const Message = packed struct {
 };
 
 test "testing variable length zero copy struct" {
+    {
+        // Relay test
         const payload = "Hello darkness my old friend";
         var msg_bytes: [try Message.calcSize(.relay, payload.len)]u8 align(@alignOf(Message)) = undefined;
 
@@ -210,15 +211,13 @@ test "testing variable length zero copy struct" {
         }
 
         {
-        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("relay network bytes: {x}\n", .{msg_bytes});
-        std.debug.print("bytes len: {d}\n", .{bytes.len});
+            std.debug.print("bytes len: {d}\n", .{msg_bytes.len});
         }
 
         if (false) {
@@ -227,6 +226,38 @@ test "testing variable length zero copy struct" {
         }
 
         try std.testing.expectEqualDeep(msg, try Message.bytesAsValue(msg.asBytes()));
+    }
+
+    {
+        // Connection test
+        const payload = "Hello darkness my old friend";
+        var msg_bytes: [try Message.calcSize(.connection, payload.len)]u8 align(@alignOf(Message)) = undefined;
+
+        // Create a view of the byte slice as a Message
+        const msg: *Message = .init(.connection, &msg_bytes);
+
+        {
+            // Initializing connection header values
+            const connection = (try msg.getSaprusTypePayload()).connection;
+            connection.src_port = 1;
+            connection.dest_port = 2;
+            connection.seq_num = 3;
+            connection.msg_id = 4;
+            connection.reserved = 5;
+            connection.options = @bitCast(@as(u8, 6));
+            @memcpy(connection.getPayload(), payload);
+        }
+
+        {
+            // 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("connection network bytes: {x}\n", .{msg_bytes});
+            std.debug.print("bytes len: {d}\n", .{msg_bytes.len});
+        }
+    }
 }
 
 const std = @import("std");