Linux Kernel Networking and Development

If you want to get a brief information about how to use Linux's linked list data structure, please see the below sample code. You can check-out the code from the github location, build and run on your own Linux development environment. /* * my_object structure. */ struct my_object { int data; struct list_head list; }; /* * list_init() */ static int list_init ( void ) { struct my_object *tmp; /* Temporary object created for each list member */ struct my_object obj_list; /* List constructed with the tmp objects */ struct list_head *pos, *n; /* Position pointers in the list */ int i; printk(KERN_INFO "list init \n " ); /* * Initialize the list object. This object is used only as the * head of the list. It doesn't have any data in it. */ INIT_LIST_HEAD(&obj_list.li...

In this post, I will explain the usage of linux's container_of macro with a sample code. If you know address of a data structure's field, you can get the address of the instance of that data structure by using the container_of macro. This is the simplest explanation of this macro. Let's say you have a function called with a pointer parameter and you know that the pointer is pointing an address of a data structure field. struct my_object { int a; int b; } obj; function(&obj->b); If you want to access the other field "a" in the function, you need to use container_of macro. Let's see the below sample code and it's output to understand it easily. /* * my_object structure. */ struct my_object { int a; int b; int c; }; /* * container_test() * Test function for usage of container_of macro. * * This function is passed a pointer which points a field of * an allocated my_obj...