{"id":883,"date":"2014-09-20T14:37:42","date_gmt":"2014-09-20T06:37:42","guid":{"rendered":"http:\/\/www.menglanglang.cn\/?p=883"},"modified":"2014-09-20T14:37:42","modified_gmt":"2014-09-20T06:37:42","slug":"linux%e4%b8%ad%e4%b8%8e%e5%86%85%e6%a0%b8%e9%80%9a%e4%bf%a1%e7%9a%84netlink%e6%9c%ba%e5%88%b6","status":"publish","type":"post","link":"http:\/\/www.menglanglang.cn\/?p=883","title":{"rendered":"Linux\u4e2d\u4e0e\u5185\u6838\u901a\u4fe1\u7684Netlink\u673a\u5236"},"content":{"rendered":"

netlink_k.c\u4e3a\u5185\u6838\u7684\u7a7a\u95f4\u7684\u7a0b\u5e8f,netlink_u.c\u4e3a\u7528\u6237\u7684\u7a7a\u95f4\u7684\u7a0b\u5e8f\u3002\u7a0b\u5e8f\u6e90\u4ee3\u7801\u9644\u5728\u540e\u9762\uff1a<\/p>\n

\u00a0\u00a0\u00a0\u5148\u8fd0\u884c\u5185\u6838\u4ee3\u7801netlink_k.ko\uff0c\u4e5f\u5c31\u662f\u5728\u6267\u884c\u5b8cmakefile\u6587\u4ef6\u540e\uff0c\u4f1a\u751f\u6210\u4e00\u4e2anetlink_k.ko\u6587\u4ef6\uff0c\u53ef\u4ee5\u4f7f\u7528\u4e0b\u9762\u7684\u547d\u4ee4\u8fdb\u884c\u5b89\u88c5\uff0cinsmod netlink_k.ko\uff0c\u4f7f\u7528lsmod\u67e5\u770b\uff0c\u5f53\u5b89\u88c5\u6210\u529f\u540e\uff0c\u7136\u540e\uff0c\u6267\u884c.\/netlink\u7528\u6237\u7a7a\u95f4\u7a0b\u5e8f\uff0c\u53ef\u4ee5\u5728\u53e6\u4e00\u4e2a\u7ec8\u7aef\u4e0b\u6267\u884cdmesg\u547d\u4ee4\uff0c\u67e5\u770b\u5185\u6838\u901a\u4fe1\u7684\u60c5\u51b5\u3002\u8fd9\u91ccnetlink\u7a0b\u5e8f\u5411\u5185\u6838\u7a7a\u95f4\u53d1\u9001\u4e00\u4e2ahello you\uff01\u5185\u6838\u8fd4\u56de\u7ed9\u4e00\u4e2aI am from kernel!\u5728\u8fd9\u91cc\u4f7f\u7528\u4e86\u4e00\u4e2a\u5b9a\u65f6\u5668\uff0c\u4e5f\u5c31\u662f\u6bcf3\u79d2\u4e2d\u53d1\u9001\u4e00\u6b21I am from kernel!\u53ea\u6709\u5185\u6838\u628a10\u4e2a\u5b57\u7b26\u4e32\u5168\u90e8\u53d1\u9001\u5b8c\u6bd5\u540e\uff0c\u7528\u6237\u7a7a\u95f4\u7684sendmsg()\u624d\u4f1a\u8fd4\u56de\uff0c\u4e5f\u5c31\u662f\u5728\u7528\u6237\u7a7a\u95f4\u7684netlink\u624d\u4f1a\u8f93\u51fa\u5185\u6838\u7a7a\u95f4\u53d1\u9001\u8fc7\u6765\u7684\u6570\u636e\uff0c\u8fd9\u91cc\u53ea\u6709\u4e00\u4e2a\u7b80\u5355\u7684\u7a0b\u5e8f\uff0c\u5e76\u6ca1\u6709\u4ec0\u4e48\u5b9e\u9645\u7684\u610f\u4e49\uff0c\u56e0\u4e3a\uff0c\u6b63\u5982\u524d\u9762\u6240\u8bf4\u7684\u4e00\u822c\u60c5\u51b5\u4e0b\u4e0d\u4f1a\u5728\u56de\u8c03\u51fd\u6570\u4e2d\u5904\u7406\u592a\u591a\u7684\u4e1c\u897f\uff0c\u4ee5\u514dsendmsg()\u51fd\u6570\u8fd4\u56de\u4e0d\u53ca\u65f6\u3002<\/wbr><\/wbr><\/wbr><\/p>\n

 <\/p>\n

netlink_k.c\uff1a<\/strong><\/p>\n

#include <linux\/init.h>
\n#include <linux\/module.h>
\n#include <linux\/timer.h>
\n#include <linux\/time.h>
\n#include <linux\/types.h>
\n#include <net\/sock.h>
\n#include <net\/netlink.h><\/p>\n

#define NETLINK_TEST 25
\n#define MAX_MSGSIZE 1024
\nint stringlength(char *s);
\nvoid sendnlmsg(char * message);
\nint pid;
\nint err;
\nstruct sock *nl_sk = NULL;
\nint flag = 0;<\/p>\n

void sendnlmsg(char *message)
\n{
\n\u00a0\u00a0\u00a0struct sk_buff *skb_1;
\n\u00a0\u00a0\u00a0struct nlmsghdr *nlh;
\n\u00a0\u00a0\u00a0int len = NLMSG_SPACE(MAX_MSGSIZE);
\n\u00a0\u00a0\u00a0int slen = 0;
\n\u00a0\u00a0\u00a0if(!message || !nl_sk)
\n\u00a0\u00a0\u00a0{
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0return ;
\n\u00a0\u00a0\u00a0}
\n\u00a0\u00a0\u00a0skb_1 = alloc_skb(len,GFP_KERNEL);
\n\u00a0\u00a0\u00a0if(!skb_1)
\n\u00a0\u00a0\u00a0{
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0printk(KERN_ERR “my_net_link:alloc_skb_1 error\\n”);
\n\u00a0\u00a0\u00a0}
\n\u00a0\u00a0\u00a0slen = stringlength(message);
\n\u00a0\u00a0\u00a0nlh = nlmsg_put(skb_1,0,0,0,MAX_MSGSIZE,0);<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0NETLINK_CB(skb_1).pid = 0;
\n\u00a0\u00a0\u00a0NETLINK_CB(skb_1).dst_group = 0;<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0\u00a0message[slen]= ‘\\0’;
\n\u00a0\u00a0\u00a0memcpy(NLMSG_DATA(nlh),message,slen+1);
\n\u00a0\u00a0\u00a0printk(“my_net_link:send message ‘%s’.\\n”,(char *)NLMSG_DATA(nlh));<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0netlink_unicast(nl_sk,skb_1,pid,MSG_DONTWAIT);<\/wbr><\/wbr><\/wbr><\/p>\n

}<\/p>\n

int stringlength(char *s)
\n{
\n\u00a0\u00a0\u00a0int slen = 0;
\n\u00a0\u00a0\u00a0for(; *s; s++){
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0slen++;
\n\u00a0\u00a0\u00a0}<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0return slen;
\n}<\/wbr><\/wbr><\/wbr><\/p>\n

void nl_data_ready(struct sk_buff *__skb)
\n{
\n\u00a0\u00a0\u00a0\u00a0struct sk_buff *skb;
\n\u00a0\u00a0\u00a0\u00a0struct nlmsghdr *nlh;
\n\u00a0\u00a0\u00a0\u00a0char str[100];
\n\u00a0\u00a0\u00a0struct completion cmpl;
\n\u00a0\u00a0\u00a0int i=10;
\n\u00a0\u00a0\u00a0\u00a0skb = skb_get (__skb);
\n\u00a0\u00a0\u00a0\u00a0if(skb->len >= NLMSG_SPACE(0))
\n\u00a0\u00a0\u00a0\u00a0{
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0nlh = nlmsg_hdr(skb);<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0memcpy(str, NLMSG_DATA(nlh), sizeof(str));
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0printk(“Message received:%s\\n”,str) ;
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0pid = nlh->nlmsg_pid;
\n\u00a0\u00a0\u00a0while(i–)
\n\u00a0\u00a0\u00a0{
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0init_completion(&cmpl);
\n\u00a0\u00a0\u00a0\u00a0wait_for_completion_timeout(&cmpl,3 * HZ);
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0sendnlmsg(“I am from kernel!”);
\n\u00a0\u00a0\u00a0}
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0flag = 1;
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0kfree_skb(skb);
\n\u00a0\u00a0\u00a0}<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

}<\/wbr><\/p>\n

\/\/ Initialize netlink<\/p>\n

int netlink_init(void)
\n{
\n\u00a0\u00a0\u00a0nl_sk = netlink_kernel_create(&init_net, NETLINK_TEST, 1,
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0nl_data_ready, NULL, THIS_MODULE);<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0if(!nl_sk){
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0printk(KERN_ERR “my_net_link: create netlink socket error.\\n”);
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0return 1;
\n\u00a0\u00a0\u00a0}<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0printk(“my_net_link_3: create netlink socket ok.\\n”);
\n\u00a0\u00a0\u00a0return 0;
\n}<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

static void netlink_exit(void)
\n{
\n\u00a0\u00a0\u00a0if(nl_sk != NULL){
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0sock_release(nl_sk->sk_socket);
\n\u00a0\u00a0\u00a0}<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0printk(“my_net_link: self module exited\\n”);
\n}<\/wbr><\/wbr><\/wbr><\/p>\n

module_init(netlink_init);
\nmodule_exit(netlink_exit);<\/p>\n

MODULE_AUTHOR(“frankzfz”);
\nMODULE_LICENSE(“GPL”);<\/p>\n

 <\/p>\n

netlink_u.c\uff1a<\/strong><\/p>\n

#include <sys\/stat.h>
\n#include <unistd.h>
\n#include <stdio.h>
\n#include <stdlib.h>
\n#include <sys\/socket.h>
\n#include <sys\/types.h>
\n#include <string.h>
\n#include <asm\/types.h>
\n#include <linux\/netlink.h>
\n#include <linux\/socket.h>
\n#include <errno.h><\/p>\n

#define NETLINK_TEST 25
\n#define MAX_PAYLOAD 1024 \/\/ maximum payload size<\/p>\n

int main(int argc, char* argv[])
\n{
\n\u00a0\u00a0\u00a0int state;
\n\u00a0\u00a0\u00a0struct sockaddr_nl src_addr, dest_addr;
\n\u00a0\u00a0\u00a0struct nlmsghdr *nlh = NULL;
\n\u00a0\u00a0\u00a0struct iovec iov;
\n\u00a0\u00a0\u00a0struct msghdr msg;
\n\u00a0\u00a0\u00a0int sock_fd, retval;
\n\u00a0\u00a0\u00a0int state_smg = 0;
\n\u00a0\u00a0\u00a0\/\/ Create a socket<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0sock_fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_TEST);
\n\u00a0\u00a0\u00a0if(sock_fd == -1){
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0printf(“error getting socket: %s”, strerror(errno));
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0return -1;
\n\u00a0\u00a0\u00a0}<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0\/\/ To prepare binding<\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0memset(&msg,0,sizeof(msg));
\n\u00a0\u00a0\u00a0memset(&src_addr, 0, sizeof(src_addr));
\n\u00a0\u00a0\u00a0src_addr.nl_family = AF_NETLINK;
\n\u00a0\u00a0\u00a0src_addr.nl_pid = getpid(); \/\/ self pid<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0src_addr.nl_groups = 0; \/\/ multi cast
\n\u00a0\u00a0\u00a0retval = bind(sock_fd, (struct sockaddr*)&src_addr, sizeof(src_addr));
\n\u00a0\u00a0\u00a0if(retval < 0){
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0printf(“bind failed: %s”, strerror(errno));
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0close(sock_fd);
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0return -1;
\n\u00a0\u00a0\u00a0}<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0\/\/ To prepare recvmsg<\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0nlh = (struct nlmsghdr *)malloc(NLMSG_SPACE(MAX_PAYLOAD));
\n\u00a0\u00a0\u00a0if(!nlh){
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0printf(“malloc nlmsghdr error!\\n”);
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0close(sock_fd);
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0return -1;
\n\u00a0\u00a0\u00a0}<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0memset(&dest_addr,0,sizeof(dest_addr));
\n\u00a0\u00a0\u00a0dest_addr.nl_family = AF_NETLINK;
\n\u00a0\u00a0\u00a0dest_addr.nl_pid = 0;
\n\u00a0\u00a0\u00a0dest_addr.nl_groups = 0;<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0nlh->nlmsg_len = NLMSG_SPACE(MAX_PAYLOAD);
\n\u00a0\u00a0\u00a0nlh->nlmsg_pid = getpid();
\n\u00a0\u00a0\u00a0nlh->nlmsg_flags = 0;
\n\u00a0\u00a0\u00a0strcpy(NLMSG_DATA(nlh),”Hello you!”);<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0iov.iov_base = (void *)nlh;
\n\u00a0\u00a0iov.iov_len = NLMSG_SPACE(MAX_PAYLOAD);
\n\u00a0\u00a0\u00a0\/\/ iov.iov_len = nlh->nlmsg_len;<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0memset(&msg, 0, sizeof(msg));
\n\u00a0
\n\u00a0\u00a0\u00a0msg.msg_name = (void *)&dest_addr;
\n\u00a0\u00a0\u00a0msg.msg_namelen = sizeof(dest_addr);
\n\u00a0\u00a0\u00a0msg.msg_iov = &iov;
\n\u00a0\u00a0\u00a0msg.msg_iovlen = 1;<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0printf(“state_smg\\n”);
\n\u00a0\u00a0\u00a0state_smg = sendmsg(sock_fd,&msg,0);<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0if(state_smg == -1)
\n\u00a0\u00a0\u00a0{
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0printf(“get error sendmsg = %s\\n”,strerror(errno));
\n\u00a0\u00a0\u00a0}<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0memset(nlh,0,NLMSG_SPACE(MAX_PAYLOAD));
\n\u00a0\u00a0\u00a0printf(“waiting received!\\n”);
\n\u00a0\u00a0\u00a0\/\/ Read message from kernel<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0while(1){
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0printf(“In while recvmsg\\n”);
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0state = recvmsg(sock_fd, &msg, 0);
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0if(state<0)
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0{
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0printf(“state<1”);
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0}
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0printf(“In while\\n”);
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0printf(“Received message: %s\\n”,(char *) NLMSG_DATA(nlh));
\n\u00a0\u00a0\u00a0}<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0close(sock_fd);<\/wbr><\/wbr><\/wbr><\/p>\n

\u00a0\u00a0\u00a0return 0;
\n}<\/wbr><\/wbr><\/wbr><\/p>\n

 <\/p>\n

makefile\uff1a<\/strong><\/p>\n

obj-m := netlink_k.o
\nKERNELBUILD := \/lib\/modules\/`uname -r`\/build
\ndefault:
\n@echo “BUILE Kmod”
\n@make -C $(KERNELBUILD) M=$(shell pwd) modules
\ngcc -o netlink_u netlink_u.c
\nclean:
\n@echo ” CLEAN kmod”
\n@rm -rf *.o
\n@rm -rf .depend .*.cmd *.ko *.mod.c .tmp_versions *.symvers .*.d<\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/wbr><\/p>\n

 <\/p>\n

\u4e0b\u9762\u662f\u4f7f\u7528dmesg\u547d\u4ee4\u8f93\u51fa\u7684\u4fe1\u606f\uff1a<\/strong><\/p>\n

[873791.498039] my_net_link_3: create netlink socket ok.<\/p>\n

[873810.263676] Message received:Hello<\/p>\n

[873813.260848] my_net_link_4:send message ‘I am from kernel!’.<\/p>\n

[873816.260821] my_net_link_4:send message ‘I am from kernel!’.<\/p>\n

[873819.260860] my_net_link_4:send message ‘I am from kernel!’.<\/p>\n

[873822.260762] my_net_link_4:send message ‘I am from kernel!’.<\/p>\n

[873825.260883] my_net_link_4:send message ‘I am from kernel!’.<\/p>\n

[873828.260669] my_net_link_4:send message ‘I am from kernel!’.<\/p>\n

[873831.260714] my_net_link_4:send message ‘I am from kernel!’.<\/p>\n

[873834.260683] my_net_link_4:send message ‘I am from kernel!’.<\/p>\n

[873837.260666] my_net_link_4:send message ‘I am from kernel!’.<\/p>\n

[873840.260632] my_net_link_4:send message ‘I am from kernel!’.<\/p>\n","protected":false},"excerpt":{"rendered":"

netlink_k.c\u4e3a\u5185\u6838\u7684\u7a7a\u95f4\u7684\u7a0b\u5e8f,netlink_u.c\u4e3a\u7528\u6237\u7684\u7a7a\u95f4\u7684\u7a0b\u5e8f\u3002\u7a0b\u5e8f\u6e90\u4ee3\u7801\u9644\u5728\u540e\u9762\uff1a \u00a0\u00a0\u00a0\u5148\u8fd0\u884c\u5185\u6838\u4ee3\u7801netlink_k.ko\uff0c\u4e5f\u5c31\u662f\u5728\u6267\u884c\u5b8cmakefile\u6587\u4ef6\u540e\uff0c\u4f1a\u751f\u6210\u4e00\u4e2anetlink_k.ko\u6587\u4ef6\uff0c\u53ef\u4ee5\u4f7f\u7528\u4e0b … \u7ee7\u7eed\u9605\u8bfb →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ai_generated_summary":"","wpai_meta_description":"","footnotes":""},"categories":[227],"tags":[602,261,282],"class_list":["post-883","post","type-post","status-publish","format-standard","hentry","category-linux","tag-linux","tag-261","tag-282"],"_links":{"self":[{"href":"http:\/\/www.menglanglang.cn\/index.php?rest_route=\/wp\/v2\/posts\/883","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.menglanglang.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.menglanglang.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.menglanglang.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.menglanglang.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=883"}],"version-history":[{"count":0,"href":"http:\/\/www.menglanglang.cn\/index.php?rest_route=\/wp\/v2\/posts\/883\/revisions"}],"wp:attachment":[{"href":"http:\/\/www.menglanglang.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=883"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.menglanglang.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=883"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.menglanglang.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=883"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}