直接可用的最简单情况下的netlink内核态与用户态通信程序

内核态

 

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include

MODULE_LICENSE("GPL");

DECLARE_MUTEX(receive_sem);

unsigned int i;
static struct sock *nlfd;

static void kernel_receive(struct sock *sk, int len)
{
 struct sk_buff *send_skb;
 int user_pid;
 printk("receive a netlink \n");
 do
 {
  struct sk_buff *skb;
  if(down_trylock(&receive_sem))
  return;
  while((skb = skb_dequeue(&sk->receive_queue)) != NULL)
  {
   printk("skb->len = %x\n",skb->len);
   for(i=0;ilen;i++)
   printk("skb data are %x\n",skb->data[i]);
   user_pid=skb->data[0];
//   kfree_skb(skb);
   send_skb=alloc_skb(102,GFP_ATOMIC);
   for(i=0;i<100;i++)
    send_skb->data[i]=0x66;
   send_skb->len=100;
   printk("skb->data[0] = %x\n",user_pid);
   netlink_unicast(nlfd,send_skb,user_pid,MSG_DONTWAIT);
   up(&receive_sem);
  }
 }while(nlfd && nlfd->receive_queue.qlen);
}

static int __init netlink_init(void)
{
// struct sk_buff *skb;
 struct sk_buff *send_skb;

 printk("22 netlink kernel start\n");
 nlfd = netlink_kernel_create(NETLINK_USERSOCK,kernel_receive);
 if(!nlfd)
 {
  printk("can not create a netlink socket\n");
  return -1;
 }
 printk("nlfd=%x\n netlink_kernel_create success\n",nlfd);
 
/* skb=alloc_skb(10,GFP_ATOMIC);
 skb->data[0]=0x55;
 skb->data[1]=0x55;
 netlink_unicast(nlfd,skb,0,MSG_DONTWAIT);*/
// if(skb)kfree_skb(skb);

/* printk("send skb to kernel\n");
 send_skb=alloc_skb(102,GFP_ATOMIC);
 for(i=0;i<100;i++)
  send_skb->data[i]=0x66;
 send_skb->len=100;
 netlink_unicast(nlfd,send_skb,0,MSG_DONTWAIT);*/
 return 0;
}

static void __exit netlink_fini(void)
{
 if(nlfd)
 {
  sock_release(nlfd->socket);
 }
 printk("exit \n");
}

module_init(netlink_init);
module_exit(netlink_fini);

用户态****************************

 

#include
#include
#include
#include
#include
#include
#include
#include
#include "imp2.h"

unsigned int i;
static int skfd;
struct msg_to_kernel
{
 struct nlmsghdr hdr;
};
struct u_packet_info
{
 struct nlmsghdr hdr;
 struct packet_info p_info;
};
static void sig_int(int signo)
{
 struct sockaddr_nl kpeer;
 struct msg_to_kernel message;
 
 memset(&kpeer,0,sizeof(kpeer));
 kpeer.nl_family=AF_NETLINK;
 kpeer.nl_pid=0;
 kpeer.nl_groups=0;
 
 memset(&message,0,sizeof(message));
 message.hdr.nlmsg_len=NLMSG_LENGTH(0);
 message.hdr.nlmsg_flags=0;
 message.hdr.nlmsg_type=IMP2_CLOSE;
 message.hdr.nlmsg_pid=getpid();
 
 sendto(skfd,&message,message.hdr.nlmsg_len,0,(struct sockaddr *)(&kpeer),sizeof(kpeer));
 
 close(skfd);
 exit(0);
}

main()
{
 struct sockaddr_nl local;
 struct sockaddr_nl kpeer;
 struct msg_to_kernel message;
 struct u_packet_info info;
 struct in_addr addr;
 int kpeerlen;
 int rcvlen=0;
 int sendlen=0;
 char data[100]={0x00,0x01,0x02,0x03,0x56};
 char re_data[10]={0x00,0x00,0x00,0x00};
 unsigned int i;

 printf(" test1\n");
 skfd=socket(PF_NETLINK,SOCK_RAW,NETLINK_USERSOCK);
 if(skfd<0)
 {
  printf("can not create a netlink socket\n");
  exit(0);
 }

 memset(&local,0,sizeof(local));
 local.nl_family=AF_NETLINK;
 local.nl_pid=getpid();
 local.nl_groups=0;

 if(bind(skfd,(struct sockaddr *)&local,sizeof(local))!=0)
 {
  printf("bind() error\n");
  return -1;
 }

// signal(SIGINT,sig_int);

 memset(&kpeer,0,sizeof(kpeer));
 kpeer.nl_family=AF_NETLINK;
 kpeer.nl_pid=getpid();
 kpeer.nl_groups=0;
 memset(&message,0,sizeof(message));
 message.hdr.nlmsg_len=NLMSG_LENGTH(0);
 message.hdr.nlmsg_flags=0;
 message.hdr.nlmsg_type=IMP2_U_PID;
 message.hdr.nlmsg_pid=local.nl_pid;
 
 data[0]=local.nl_pid;
 printf(" ap pid = %x\n",local.nl_pid);
 for(i=1;i<100;i++)
  data[i]=0x77;
 sendto(skfd,&data,100,0,(struct sockaddr *)&kpeer,sizeof(kpeer));

 while(1)
 {
  sleep(1);
  printf(" receiving ....\n");
  kpeerlen=sizeof(struct sockaddr_nl);
  printf(" 1##\n");
  rcvlen=recvfrom(skfd,&re_data,200,0,(struct sockaddr *)&kpeer,&kpeerlen);
  printf("rcvlen = %d\n",rcvlen);
  if(rcvlen)
  {
   printf("receive data\n");
   for(i=0;i     printf("re_data = %x\n",re_data[i]);
  }
 }
 
 return 0;
}