use Graph;

my $G = Graph->new(); # Create Graph object with listed verteces

# Obtain a route in @ip_addrs, then:
add_chain $G, @ip_addrs;

# lather, rinse, and repeat

sub add_chain {
    my $g = shift;
    # add_edge produces any vertices not already present
    $g->add_edge($_[$_-1],$_[$_]) for 1..scalar(@_)-1;
}