zaprus/src/main.zig

//! By convention, main.zig is where your main function lives in the case that
//! you are building an executable. If you are making a library, the convention
//! is to delete this file and start with root.zig instead.

const is_debug = builtin.mode == .Debug;

const SaprusPacketType = enum(u16) {
    relay = 0x003C,
    file_transfer = 0x8888,
};

const SaprusMessage = union(SaprusPacketType) {
    relay: struct {
        dest: [4]u8,
        payload: []u8,
    },
    file_transfer: void, // unimplemented

    const Self = @This();

    fn toBytes(s: Self, allocator: Allocator) ![]u8 {
        var buf = std.ArrayList(u8).init(allocator);
        const w = buf.writer();
        try w.writeInt(u16, @intFromEnum(@as(SaprusPacketType, s)), .big);

        switch (s) {
            .relay => |relay| {
                try w.writeAll(&relay.dest);
                try w.writeInt(u16, @intCast(relay.payload.len), .big);
                try w.writeAll(relay.payload);
            },
            .file_transfer => unreachable,
        }

        return buf.toOwnedSlice();
    }
};

pub fn main() !void {
    const DBA = std.heap.DebugAllocator(.{});
    var dba: ?DBA = if (comptime is_debug) DBA.init else null;
    defer if (dba) |*d| {
        _ = d.deinit();
    };

    var allocator = if (dba) |*d| d.allocator() else std.heap.smp_allocator;

    const msg = SaprusMessage{
        .relay = .{
            .dest = .{ 255, 255, 255, 255 },
            .payload = @ptrCast(@constCast("Hello darkness my old friend")),
        },
    };

    const msg_bytes = try msg.toBytes(allocator);
    defer allocator.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 network = @import("network");