gen_dnhostop
b0 = gen_dnhostop(addr, Q_SRC, base_off);
b1 = gen_dnhostop(addr, Q_DST, base_off);
b0 = gen_dnhostop(addr, Q_SRC, base_off);
b1 = gen_dnhostop(addr, Q_DST, base_off);
return gen_dnhostop(addr, dir, 0);
static struct block *gen_dnhostop(bpf_u_int32, int, u_int);