linux内核调用用户空间程序

  //内核发送端----------->
　1 #include 
  2 #include 
  3 #include 
  4 #include 
  5 #include 
  6 #include 
  7 
  8 #include         
  9 #include    
 10 #include     
 11 
 12 #define NETLINK_TEST 17  
 13 #define MAX_MSGSIZE 1024  
 14 struct sock *nl_sk = NULL;
 15 
 16 static int ForkBroadprocess(void);
 17 static int netlink_init(void);
 18 // Send message by netlink  
 19 static void sendnlmsg(char *message);
 20 static void netlink_exit(void);
 21 static int stringlength(char *s);
 22 
 23 
 24 /*
 25 *    开启发送二层广播进程
 26 */
 27 static int ForkBroadprocess(void)
 28 {
 29     netlink_init();
 30     //netlink_exit();
 31     /*
 32     static char * argv_init[] = { "/usr/sbin/sendBroadcast", NULL};
 33     char * envp_init[] = {"HOME=/", "TERM=linux", "PATH=/sbin:/bin:/usr/sbin:/usr/bin", NULL};
 34     kernel_execve(argv_init[0], argv_init, envp_init);    
 35     printk("===============kernel_execve=================\n");
 36     */
 37     return 0;
 38 }
 39 
 40 static int netlink_init(void)  
 41 {  
 42     if(nl_sk == NULL)
 43     {
 44         nl_sk = netlink_kernel_create(&init_net, NETLINK_TEST, 1,NULL, NULL, THIS_MODULE);  
 45     }
 46     if(!nl_sk){  
 47         printk(KERN_ERR "my_net_link: create netlink socket error.\n");  
 48         return 1;  
 49     }  
 50   
 51     printk("my_net_link: create netlink socket ok.\n");  
 52     sendnlmsg("sendBroadcast");  
 53   
 54     return 0;  
 55 }  
 56 
 57 static int stringlength(char *s)  
 58 {  
 59     int slen = 0;  
 60   
 61     for(; *s; s++){  
 62         slen++;  
 63     }  
 64   
 65     return slen;  
 66 }  
 67 
 68 // Send message by netlink  
 69 static void sendnlmsg(char *message)    
 70 {  
 71     struct sk_buff *skb = NULL;  
 72     struct nlmsghdr *nlh = NULL; 
 73     char szMessage[32] = {0};    
 74     int len = NLMSG_SPACE(MAX_MSGSIZE);  
 75     int slen = 0;  
 76       
 77     if(!message || !nl_sk){  
 78         return;  
 79     }  
 80   
 81     // Allocate a new sk_buffer  
 82     skb = alloc_skb(len, GFP_KERNEL);  
 83     if(!skb){  
 84         printk(KERN_ERR "my_net_link: alloc_skb Error.\n");  
 85         return;  
 86     }  
 87   
 88     slen = stringlength(message);  
 89     printk("my_net_link: send message slen '%d'.\n", slen);  
 90     //Initialize the header of netlink message  
 91     nlh = nlmsg_put(skb, 0, 0, 0, MAX_MSGSIZE, 0);  
 92     NETLINK_CB(skb).pid = 0; // from kernel  
 93     NETLINK_CB(skb).dst_group = 1; // multi cast  
 94     //message[slen] = '/0';  
 95     
 96     memset(szMessage, 0x0, 32);
 97     memcpy(szMessage, message, slen);
 98     memcpy(NLMSG_DATA(nlh), szMessage, slen + 1);  
 99     printk("my_net_link: send message '%s'.\n", (char *)NLMSG_DATA(nlh));  
100   
101     //send message by multi cast  
102     netlink_broadcast(nl_sk, skb, 0, 1, GFP_KERNEL);   
103     return;  
104 }  
105   
106 static void netlink_exit(void)     
107 {     
108     if(nl_sk != NULL){  
109         sock_release(nl_sk->sk_socket);  
110     }  
111   
112     printk("my_net_link: self module exited/n");     
113 }  

 //用户空间接收端

  1 #include   
  2 #include   
  3 #include   
  4 #include   
  5 #include   
  6 #include   
  7 #include <string.h>  
  8 #include   
  9 #include   
 10 #include   
 11 #include   
 12 #include 
 13 
 14 #define NETLINK_TEST 17  
 15 #define MAX_PAYLOAD 1024  // maximum payload size  
 16   
 17 static int OperateFun();
 18 
 19 int main(int argc, char* argv[])  
 20 {  
 21     struct sockaddr_nl src_addr, dest_addr;  
 22     struct nlmsghdr *nlh = NULL;  
 23     struct iovec iov;  
 24     struct msghdr msg;  
 25     int sock_fd, retval;  
 26       
 27     // Create a socket  
 28     sock_fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_TEST);  
 29     if(sock_fd == -1){  
 30         printf("error getting socket: %s", strerror(errno));  
 31         return -1;  
 32     }  
 33     printf(" getting socket: %d\n", sock_fd);    
 34     // To prepare binding  
 35     memset(&src_addr, 0, sizeof(src_addr));  
 36     src_addr.nl_family = AF_NETLINK;   
 37     src_addr.nl_pid = getpid();  // self pid   
 38     src_addr.nl_groups = 1; // multi cast  
 39     printf(" src_addr.nl_pid: %d\n", src_addr.nl_pid);    
 40     retval = bind(sock_fd, (struct sockaddr*)&src_addr, sizeof(src_addr));  
 41     if(retval < 0){  
 42         printf("bind failed: %s", strerror(errno));  
 43         close(sock_fd);  
 44         return -1;  
 45     }  
 46      //printf(" ====================0000\n");     
 47     // To prepare recvmsg  
 48     nlh = (struct nlmsghdr *)malloc(NLMSG_SPACE(MAX_PAYLOAD));  
 49     if(!nlh){  
 50         printf("malloc nlmsghdr error!/n");  
 51         close(sock_fd);  
 52         return -1;  
 53     }  
 54   //printf(" ====================11111\n");   
 55     memset(nlh, 0, NLMSG_SPACE(MAX_PAYLOAD));  
 56     iov.iov_base = (void *)nlh;  
 57     iov.iov_len = NLMSG_SPACE(MAX_PAYLOAD);  
 58   //printf(" ====================22222\n");   
 59     memset(&msg, 0, sizeof(msg));  
 60     memset(&dest_addr, 0, sizeof(dest_addr));  
 61     msg.msg_name = (void *)&dest_addr;  
 62     msg.msg_namelen = sizeof(dest_addr);  
 63     msg.msg_iov = &iov;  
 64     msg.msg_iovlen = 1;  
 65   //printf(" ====================33333\n");   
 66     // Read message from kernel  
 67 
 68     int nSelectRet = 0;
 69     fd_set fdReadSet;
 70     struct timeval stTimeOut = {0};
 71 
 72     for(;;)
 73     {
 74         //wait for a message
 75         //printf(" ====================4444444\n");   
 76         FD_ZERO(&fdReadSet);
 77         FD_SET(sock_fd, &fdReadSet);
 78         //printf(" ====================55555555\n");  
 79         stTimeOut.tv_sec = 2;
 80         stTimeOut.tv_usec = 0;
 81         nSelectRet = select(sock_fd + 1, &fdReadSet, NULL, NULL, &stTimeOut);
 82     
 83 
 84         if(0 > nSelectRet)
 85         {
 86             printf( "select error !");
 87         }
 88         else if(0 == nSelectRet)
 89         {
 90             printf( "select time out !\n");
 91 
 92         }
 93         else
 94         {
 95             if(FD_ISSET(sock_fd, &fdReadSet))
 96             {
 97                 recvmsg(sock_fd, &msg, 0);  
 98                 printf("Received message: %s\n", NLMSG_DATA(nlh));  
 99                 OperateFun();
100             }
101         }
102     }
103     close(sock_fd);  
104   
105     return 0;  
106 }

 

转载于:https://www.cnblogs.com/liwentao1091/p/4535881.html