Copy pointer to struct to new pointer to copy of the struct in in C

i have this case where i want to store pointers to structs in some hash table (linked list ) i have :

struct Base {
 int age;
};

struct Base *l1 = malloc(sizeof(struct Base )); 
l1->age = 20;

now here i stuck somewhere in the code (deep down) i have function which gives me the pointer to Base

callback_(struct Base *l)
{

i don't want to point to l1 which will be gone when the callback ends i want to create new pointer to base which the values of the l1 (age)

struct Base  *l2 = ???;

do i need to copy each value ? (deep copy ) in realty there are many members and allot of data so i need something better then deep copy