Umm, serializing a sub is not easy in perl as far as I know, but what about storing your sub's source as a string, send it over the socket as plain text, then eval at the other end of the socket?

my $sub_str = q{
  sub {
    my $n = shift;
    return $n + 1;
  }
};

# send the string through the socket

# at the far end of the socket:
my $sub_ref = eval $sub_str;
print $sub_ref->(2), "\n";
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