http://blog.csdn.net/mrpre/article/details/78041431
本文代码实现:用户进程发送“nihao”给内核,内核回复“niyehao”给用户态。
1:添加自己的宏。
2:编写用户态程序。
3:编写内核态程序。
内核态,需要全局变量进行数据的交互。
在模块init的时候,可以:
netlinkfd = netlink_kernel_create(&init_vrf,
NL_MY, 0, kernel_receive, NULL, THIS_MODULE);
NL_MY是加载netlink.h头文件中的宏。
kernel_recv是函数的地址,用以接收处理用户态的数据
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int process_message_thread(void *arg)
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{
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struct sk_buff *skb = (struct sk_buff *)(arg);
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struct sk_buff *newskb;
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int opp_id;
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struct struReq_s *msg = (struct struReq_s *) skb->data;
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opp_id = msg->pid;
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struct struReq_s *needtosend = kmalloc(sizeof(struct struReq_s) + strlen("niyehao"),GFP_KERNEL);
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needtosend->data_len = strlen("niyehao");
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memcpy(needtosend->data,"niyehao", needtosend->data_len);
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newskb = alloc_skb(sizeof(struct struReq_s) + strlen("niyehao"), GFP_ATOMIC);
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skb_put(newskb,sizeof(struct struReq_s) + strlen("niyehao"));
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memcpy(newskb->data,needtosend,sizeof(struct struReq_s) + strlen("niyehao"));
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netlink_unicast(netlinkfd, newskb, opp_id, MSG_DONTWAIT);
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kfree(needtosend);
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return 0;
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}
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u32 nt = 0;
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void kernel_receive(struct sk_buff *skb)
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{
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printk("#########recv###########\n");
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process_message_thread(skb);
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printk("#########leave###########\n");
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}
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int netlink_socket = -1;
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int main()
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{
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struct sockaddr_nl src_addr;
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s32 ret;
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struct struReq_s
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{
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int pid;
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int data_len;
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char data[0];
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};
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u8 buf[1024] = {0};
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struct struReq_s *struReq = NULL;
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netlink_socket = socket(AF_NETLINK, SOCK_RAW, NL_MY);
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if(netlink_socket < 0)
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{
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return -1;
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}
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memset(&src_addr, 0, sizeof(src_addr));
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src_addr.nl_family = AF_NETLINK;
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src_addr.nl_pid = getpid();
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src_addr.nl_groups = 1;
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ret = bind(netlink_socket, (struct sockaddr *)&src_addr, sizeof(src_addr));
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if(ret < 0)
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{
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return -1;
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}
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struReq = malloc(sizeof( struct struReq_s) + 10);
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if(struReq == NULL)
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{
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printf("malloc fail\n");
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return 0;
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}
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memset(struReq, 0, sizeof(struct struReq_s) + 10);
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struReq->pid = getpid();
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struReq->data_len = 10;
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memcpy(struReq->data,"nihao",strlen("nihao"));
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memset(&src_addr, 0, sizeof(src_addr));
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src_addr.nl_family = AF_NETLINK;
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src_addr.nl_pid = 0;
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src_addr.nl_groups = 0;
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if(sendto(netlink_socket, struReq, struReq->data_len + sizeof(struct struReq_s), 0,
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(struct sockaddr *)&src_addr, sizeof(src_addr)) < 0)
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{
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return -1;
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}
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printf("user recv\n");
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/*阻塞的读*/
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memset(buf,0,1024);
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recv(netlink_socket,buf,1024,0);
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printf("recv from kernel len : %d\n",((struct struReq_s *)buf)->data_len);
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printf("recv from kernel data: %s\n",((struct struReq_s *)buf)->data);
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free(struReq);
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close(netlink_socket);
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return 0;
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}
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