Linux中list.h中函数应用实例

这些代码片段展示如何使用Linux内核模块，list，以及hash。

===================tccounter.c=====================

#include <linux/init.h>

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/list.h>

#include <linux/jhash.h>

#include <linux/ctype.h>

#include <linux/proc_fs.h>

#include <asm/uaccess.h>

MODULE_LICENSE("GPL");

static unsigned int ip = 123456789;

module_param(ip, uint, 0);

static unsigned int port = 1;

module_param(port, uint, 0);

#define TCCOUNT_SIZE 255

struct tccount

{

struct list_head list;

unsigned int ip;

unsigned short port;

unsigned short counter;

};

struct tccount tclist[TCCOUNT_SIZE];

unsigned int gethash(unsigned int ip, unsigned int port)

{

return jhash_2words(ip, port, 4)%TCCOUNT_SIZE;

}

int tccount_init(void)

{

int i;

for(i = 0; i < TCCOUNT_SIZE; i++ )

{

INIT_LIST_HEAD(&(tclist[i].list));

tclist[i].ip = 0;

tclist[i].port = 0;

tclist[i].counter = 0;

}

return 0;

}

int addNewStream(unsigned int sip, unsigned int sport)

{

unsigned int hash;

struct tccount *stream;

hash = gethash(sip, sport);

list_for_each_entry(stream, &(tclist[hash].list), list)

{

if(stream && stream->ip == sip && stream->port == sport)

{

stream->counter++;

return 0;

}

}

stream = kmalloc(sizeof(struct tccount), GFP_KERNEL);

stream->ip = sip;

stream->port = sport;

stream->counter = 1;

list_add_rcu(&(stream->list), &(tclist[hash].list));

return 0;

}

int delStream(unsigned int sip, unsigned int sport)

{

unsigned int hash;

struct tccount *stream;

hash = gethash(sip, sport);

list_for_each_entry(stream, &(tclist[hash].list), list)

{

if(stream->ip == sip && stream->port == sport)

{

stream->counter--;

if(stream->counter == 0 && stream != &tclist[hash])

{

list_del_rcu(&(stream->list));

kfree(&stream);

}

}

}

return 0;

}

unsigned short getStreamCount(unsigned int sip, unsigned int sport)

{

unsigned int hash;

struct tccount *stream;

hash = gethash(sip, sport);

list_for_each_entry(stream, &(tclist[hash].list), list)

{

if(stream->ip == sip && stream->port == sport)

return stream->counter;

}

return 0;

}

/*debug proc*/

static int proc_show_tccount(struct file *f, const char *buf, unsigned long cnt, void *data)

{

char input[32];

int r;

unsigned int ip;

unsigned int port;

unsigned short count;

if (copy_from_user(input, buf, cnt) != 0)

return -EFAULT;

r = cnt;

sscanf(input, "%u %u", &ip, &port) ;

count = getStreamCount(ip, port);

printk(KERN_ALERT "(%d, %d) counter:%u/n",ip, port, count);

return cnt;

}

static int proc_set_tccount(struct file *f, const char *buf, unsigned long cnt, void *data)

{

char input[32];

int r;

unsigned int ip;

unsigned int port;

unsigned int count;

if (copy_from_user(input, buf, cnt) != 0)

return -EFAULT;

r = cnt;

sscanf(input, "%u %u", &ip, &port) ;

count = addNewStream(ip, port);

printk(KERN_ALERT "(%d, %d) has been added/n", ip, port);

return cnt;

}

static int proc_del_tccount(struct file *f, const char *buf, unsigned long cnt, void *data)

{

char input[32];

int r;

unsigned int ip;

unsigned int port;

unsigned int count;

if (copy_from_user(input, buf, cnt) != 0)

return -EFAULT;

r = cnt;

sscanf(input, "%u %u", &ip, &port) ;

count = delStream(ip, port);

printk(KERN_ALERT "a stream of (%d, %d) has been deleted/n", ip, port);

return cnt;

}

static int proc_add(void)

{

char tmp[32];

struct proc_dir_entry *proc_tcctl, *pentry;

sprintf(tmp, "tccount");

proc_tcctl = proc_mkdir(tmp, NULL);

sprintf(tmp, "show");

pentry = create_proc_entry(tmp, 0644, proc_tcctl);

pentry->data= NULL;

pentry->read_proc   = NULL;

pentry->write_proc  = proc_show_tccount;

pentry->owner   = THIS_MODULE;

sprintf(tmp, "del");

pentry = create_proc_entry(tmp, 0644, proc_tcctl);

pentry->data= NULL;

pentry->read_proc   = NULL;

pentry->write_proc  = proc_del_tccount;

pentry->owner   = THIS_MODULE;

sprintf(tmp, "add");

pentry = create_proc_entry(tmp, 0644, proc_tcctl);

pentry->data= NULL;

pentry->read_proc   = NULL;

pentry->write_proc  = proc_set_tccount;

pentry->owner   = THIS_MODULE;

return 0;

}

static int hello_init(void)

{

tccount_init();

proc_add();

return 0;

}

static void hello_exit(void)

{

printk("Goodbye!/n");

}

module_init(hello_init);

module_exit(hello_exit);

====================Makefile========================

obj-m += tccounter.o

all:

make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules

clean:

make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean

====================debug方法======================
echo 8 > /proc/sys/kernel/printk
echo 1234234123 123 > /proc/tccount/show
echo 1234234123 123 > /proc/tccount/add
echo 1234234123 123 > /proc/tccount/del