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const is_debug = builtin.mode == .Debug;
const base64Enc = std.base64.Base64Encoder.init(std.base64.standard_alphabet_chars, '=');
const base64Dec = std.base64.Base64Decoder.init(std.base64.standard_alphabet_chars, '=');
const SaprusPacketType = enum(u16) {
relay = 0x003C,
file_transfer = 0x8888,
connection = 0x00E9,
_,
};
const SaprusConnectionOptions = packed struct(u8) {
opt1: bool = false,
opt2: bool = false,
opt3: bool = false,
opt4: bool = false,
opt5: bool = false,
opt6: bool = false,
opt7: bool = false,
opt8: bool = false,
};
const SaprusMessage = union(SaprusPacketType) {
const Relay = struct {
const Header = packed struct {
dest: @Vector(4, u8),
};
header: Header,
payload: []const u8,
};
const Connection = struct {
const Header = packed struct {
src_port: u16,
dest_port: u16,
seq_num: u32 = 0,
msg_id: u32 = 0,
reserved: u8 = 0,
options: SaprusConnectionOptions = .{},
};
header: Header,
payload: []const u8,
};
relay: Relay,
file_transfer: void, // unimplemented
connection: Connection,
fn toBytes(self: SaprusMessage, allocator: Allocator) ![]u8 {
var buf = std.ArrayList(u8).init(allocator);
const w = buf.writer();
try w.writeInt(u16, @intFromEnum(self), .big);
switch (self) {
.relay => |r| {
var b64_payload_buf = std.ArrayList(u8).init(allocator);
defer b64_payload_buf.deinit();
const buf_w = b64_payload_buf.writer();
try base64Enc.encodeWriter(buf_w, r.payload);
try w.writeStructEndian(r.header, .big);
try w.writeInt(u16, @intCast(b64_payload_buf.items.len), .big);
try w.writeAll(b64_payload_buf.items);
},
.file_transfer => unreachable,
.connection => |c| {
var b64_payload_buf = std.ArrayList(u8).init(allocator);
defer b64_payload_buf.deinit();
const buf_w = b64_payload_buf.writer();
try base64Enc.encodeWriter(buf_w, c.payload);
try w.writeStructEndian(c.header, .big);
try w.writeInt(u16, @intCast(b64_payload_buf.items.len), .big);
try w.writeAll(b64_payload_buf.items);
},
}
return buf.toOwnedSlice();
}
fn fromBytes(bytes: []const u8, allocator: Allocator) !SaprusMessage {
var s = std.io.fixedBufferStream(bytes);
const r = s.reader();
switch (@as(SaprusPacketType, @enumFromInt(try r.readInt(u16, .big)))) {
.relay => {
const header = try r.readStructEndian(Relay.Header, .big);
const len = try r.readInt(u16, .big);
var payload_b64_buf = std.ArrayList(u8).init(allocator);
defer payload_b64_buf.deinit();
try r.readAllArrayList(&payload_b64_buf, len);
const payload = try allocator.alloc(u8, try base64Dec.calcSizeForSlice(payload_b64_buf.items));
try base64Dec.decode(payload, payload_b64_buf.items);
return .{
.relay = .{
.header = header,
.payload = payload,
},
};
},
else => unreachable,
}
}
};
pub fn main() !void {
var dba: ?DebugAllocator = if (comptime is_debug) DebugAllocator.init else null;
defer if (dba) |*d| {
_ = d.deinit();
};
var gpa = if (dba) |*d| d.allocator() else std.heap.smp_allocator;
const msg = SaprusMessage{
.relay = .{
.header = .{ .dest = .{ 255, 255, 255, 255 } },
.payload = "Hello darkness my old friend",
},
};
const msg_bytes = try msg.toBytes(gpa);
defer gpa.free(msg_bytes);
try network.init();
defer network.deinit();
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 dest_addr = network.EndPoint{
.address = network.Address{ .ipv4 = network.Address.IPv4.broadcast },
.port = 8888,
};
try sock.bind(bind_addr);
_ = try sock.sendTo(dest_addr, msg_bytes);
}
const builtin = @import("builtin");
const std = @import("std");
const Allocator = std.mem.Allocator;
const DebugAllocator = std.heap.DebugAllocator(.{});
const network = @import("network");
test "Round trip toBytes and fromBytes" {
const gpa = std.testing.allocator;
const msg = SaprusMessage{
.relay = .{
.header = .{ .dest = .{ 255, 255, 255, 255 } },
.payload = "Hello darkness my old friend",
},
};
const to_bytes = try msg.toBytes(gpa);
defer gpa.free(to_bytes);
const from_bytes = try SaprusMessage.fromBytes(to_bytes, gpa);
defer gpa.free(from_bytes.relay.payload);
try std.testing.expectEqualDeep(msg, from_bytes);
}
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