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);