inval.zig

const std = @import("std");
const os = std.os;
const net = std.net;

pub fn main() anyerror!void {
    const address_all = net.Address.initIp4([_]u8{ 0, 0, 0, 0 }, 4040);
    const address = net.Address.initIp4([_]u8{ 127, 0, 0, 1 }, 4040);

    const address_target_ok = net.Address.initIp4([_]u8{ 127, 0, 0, 42 }, 4040);
    const address_target_notok = net.Address.initIp4([_]u8{ 192, 168, 1, 1 }, 4040);

    const sock_flags = os.SOCK.DGRAM | os.SOCK.CLOEXEC | os.SOCK.NONBLOCK;

    const buf = "hello";
    {
        var fd_all = try os.socket(address_all.any.family, sock_flags, os.IPPROTO.UDP);
        defer os.closeSocket(fd_all);

        try os.bind(fd_all, &address_all.any, address_all.getOsSockLen());

        _ = try os.sendto(fd_all, buf, os.MSG.NOSIGNAL, &address_target_ok.any, address_target_ok.getOsSockLen());
        _ = try os.sendto(fd_all, buf, os.MSG.NOSIGNAL, &address_target_notok.any, address_target_notok.getOsSockLen());
    }

    {
        var fd = try os.socket(address.any.family, sock_flags, os.IPPROTO.UDP);
        defer os.closeSocket(fd);

        try os.bind(fd, &address.any, address.getOsSockLen());
        _ = try os.sendto(fd, buf, os.MSG.NOSIGNAL, &address_target_ok.any, address_target_ok.getOsSockLen());
        _ = try os.sendto(fd, buf, os.MSG.NOSIGNAL, &address_target_notok.any, address_target_notok.getOsSockLen()); // This last one get .INVAL
    }
}