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本帖最后由 duanjigang 于 2017-03-11 22:27 编辑
看了点net_device 部分的东西，还有netlink编程的文档和代码，搞了一个枚举并查看linux系统网络设备的程序。
内核模块与用户程序通过netlink socket进行通讯。
目前的功能：
(1):查看net_device列表
插入内核模块后，调用用户态程序发送命令进行查看，比如
能返回所有net_device 的名称列表
(2):查看任意一个net_device的状态信息。
比如
返回
然后就可以使用
查看eth1的状态
说明：
内核部分代码并非原创，参考修改网上的代码实现的。
未来的设想：可以类似于iptables一样，给这个程序加入set命令，目前相当于只有get功能，获取信息，加入set后就能修改网络设备的信息了。
目前的ifconfig命令是通过ioctl来实现的，感兴趣的朋友可以尝试用netlink 进行通讯，实现ifconfig.===
==============内核模块的代码=========================
//net_link.c by duanjigang
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/config.h>
#include <linux/types.h>
#include <linux/if.h>
#include <linux/timer.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/if_arp.h>
#include <linux/sched.h>
#include <net/sock.h>
#include <linux/netlink.h>
#define NETLINK_GENERIC 18
#define BUF_SIZE 1024
static struct sock *netlink_exam_sock;
static unsigned char szBuff[BUF_SIZE];
static int exit_flag = 0;
static DECLARE_COMPLETION(exit_completion);
static void get_dev_info(int type, const char* name);
static void recv_handler(struct sock * sk, int length)
{
wake_up(sk->sk_sleep);
}
static int process_message_thread(void * pData)
{
struct sk_buff * skb = NULL;
struct nlmsghdr * nlhdr = NULL;
int len;
char data[1024] = {0};
DEFINE_WAIT(wait);
daemonize("cme_netlink");
while (exit_flag == 0)
{
prepare_to_wait(netlink_exam_sock->sk_sleep, &wait, TASK_INTERRUPTIBLE);
schedule();
finish_wait(netlink_exam_sock->sk_sleep, &wait);
while ((skb = skb_dequeue(&netlink_exam_sock->sk_receive_queue)) != NULL)
{
u32 pid;
nlhdr = (struct nlmsghdr *)skb->data;
if (nlhdr->nlmsg_len < sizeof(struct nlmsghdr))
{
printk("Corrupt netlink message.\n");
continue;
}
len = nlhdr->nlmsg_len - NLMSG_LENGTH(0);
if (len > 1024)
{
printk("netlink buffer is overflow.\n");
memcpy(data, NLMSG_DATA(nlhdr), 1024);
}
else
{
memcpy(data, NLMSG_DATA(nlhdr), len);
}
printk(data);
if(strncmp(data, "all", 3) == 0)
{
get_dev_info(0, NULL);
}
else
{
get_dev_info(1, data);
}
pid = nlhdr->nlmsg_pid;
nlhdr->nlmsg_pid = 0;
nlhdr->nlmsg_flags = 0;
NETLINK_CB(skb).pid = 0;
NETLINK_CB(skb).dst_pid = pid;
NETLINK_CB(skb).dst_groups = 0;
memset(nlhdr, 0, NLMSG_SPACE(nlhdr->nlmsg_len));
strcpy(NLMSG_DATA(nlhdr), szBuff);
netlink_unicast(netlink_exam_sock, skb, pid, MSG_DONTWAIT);
}
}
complete(&exit_completion);
return 0;
}
static void get_dev_info(int ntype, const char* name)
{
int n = 1;
struct net_device * dev = dev_base;
struct net_device_stats * stats = NULL;
char type[32];
struct in_device *ind = NULL;
struct in_ifaddr *ina = NULL;
memset(szBuff, 0, 1024);
read_lock(&dev_base_lock);
while (dev)
{
char szdata[1024] ={0};
if (dev->type == ARPHRD_ETHER)
{
sprintf(type, "Ethernet");
}
else if (dev->type == ARPHRD_LOOPBACK)
{
sprintf(type, "Local Loopback");
}
else
{
sprintf(type, "%d", dev->type);
}
stats = dev->get_stats(dev);
sprintf(szdata, "%s\t", dev->name);
//printk("%s\n", dev->name);
if(ntype != 0)
{
if(strncmp(dev->name, name, strlen(name)) != 0)
{
dev = dev->next;
continue;
}
}else
{
memcpy(szBuff + strlen(szBuff), szdata, strlen(szdata));
dev = dev->next;
continue;
}
sprintf(szdata + strlen(szdata), "Link encap:%s ", type);
sprintf(szdata + strlen(szdata), "HWaddr %2.2X:%2.2X:%2.2X:%2.2X:%2.2X:%2.2X\n",
dev->dev_addr[0], dev->dev_addr[1],
dev->dev_addr[2], dev->dev_addr[3],
dev->dev_addr[4], dev->dev_addr[5]);
ind = in_dev_get(dev);
if (ind)
{
ina = (struct in_ifaddr *)ind->ifa_list;
if (ina)
{
sprintf(szdata + strlen(szdata),
"\tinet addr:%u.%u.%u.%u Bcast:%u.%u.%u.%u Mask:%u.%u.%u.%u\n",
NIPQUAD(ina->ifa_address),
NIPQUAD(ina->ifa_broadcast),
NIPQUAD(ina->ifa_mask));
}
}
sprintf(szdata + strlen(szdata), "\t");
if (dev->flags & IFF_UP) sprintf(szdata + strlen(szdata), "UP ");
if (dev->flags & IFF_BROADCAST) sprintf(szdata + strlen(szdata), "BROADCAST ");
if (dev->flags & IFF_RUNNING) sprintf(szdata + strlen(szdata), "RUNNING ");
if (dev->flags & IFF_LOOPBACK) sprintf(szdata + strlen(szdata), "LOOPBACK ");
if (dev->flags & IFF_MULTICAST) sprintf(szdata + strlen(szdata), "MULTICAST ");
sprintf(szdata + strlen(szdata), "MTU:%d\n", dev->mtu);
sprintf(szdata + strlen(szdata), "\t");
sprintf(szdata + strlen(szdata),
"RX packets:%lu errors:%lu dropped:%lu overruns:%lu frame:%lu\n",
stats->rx_packets, stats->rx_errors, stats->rx_dropped,
stats->rx_over_errors, stats->rx_frame_errors);
sprintf(szdata + strlen(szdata), "\t");
sprintf(szdata + strlen(szdata),
"TX packets:%lu errors:%lu dropped:%lu overruns:%lu carrier:%lu\n",
stats->tx_packets, stats->tx_errors, stats->tx_dropped,
stats->tx_aborted_errors, stats->tx_carrier_errors);
sprintf(szdata + strlen(szdata), "\t");
sprintf(szdata + strlen(szdata), "RX Bytes:%lu TX Bytes:%lu\n", stats->rx_bytes, stats->tx_bytes);
sprintf(szdata + strlen(szdata), "\t");
sprintf(szdata + strlen(szdata), "Interrupt:%d Base address:0x%lx\n", dev->irq, dev->base_addr);
sprintf(szdata + strlen(szdata), "\n");
n++;
dev = dev->next;
//printk("%d: %s\n", n, szdata);
memcpy(szBuff + strlen(szBuff), szdata, strlen(szdata));
}
read_unlock(&dev_base_lock);
//printk("\n==\n%d:%s==\n",n, szBuff);
}
int init_module()
{
netlink_exam_sock = netlink_kernel_create(NETLINK_GENERIC, recv_handler);
if (!netlink_exam_sock)
{
printk("Fail to create netlink socket.\n");
return 1;
}
kernel_thread(process_message_thread, NULL, CLONE_KERNEL);
return 0;
}
void cleanup_module( )
{
exit_flag = 1;
wake_up(netlink_exam_sock->sk_sleep);
wait_for_completion(&exit_completion);
sock_release(netlink_exam_sock->sk_socket);
}
MODULE_LICENSE("GPL");
MODULE_AUTHOR("duanjigang");
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==========用户态程序===================
//sender.c by cme
#include <sys/stat.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <string.h>
#include <asm/types.h>
#include <linux/netlink.h>
#include <linux/socket.h>
#define NETLINK_GENERIC 18
#define MAX_PAYLOAD 1024
struct sockaddr_nl src_addr, dst_addr;
struct nlmsghdr *nlh = NULL;
struct msghdr msg;
struct iovec iov;
int sock_fd;
int main(int argc, char **argv)
{
int i = 0;
if(argc < 2)
{
printf("usage: %s <all>/<nic name>\n", argv[0]);
exit(0);
}
sock_fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_GENERIC);
memset(&dst_addr, 0, sizeof(dst_addr));
dst_addr.nl_family = AF_NETLINK;
dst_addr.nl_pid = 0;
dst_addr.nl_groups = 0; // no multicast
nlh = (struct nlhmsghdr *)malloc(NLMSG_SPACE(MAX_PAYLOAD));
for(i = 1; i < argc; i++)
{
memset(nlh, 0, NLMSG_SPACE(MAX_PAYLOAD));
nlh->nlmsg_len = NLMSG_SPACE(MAX_PAYLOAD);
nlh->nlmsg_pid = getpid();
nlh->nlmsg_flags = 0;
strcpy(NLMSG_DATA(nlh), argv[i);
iov.iov_base = (void *)nlh;
iov.iov_len = nlh->nlmsg_len;
msg.msg_name = (void *)&dst_addr;
msg.msg_namelen = sizeof(dst_addr);
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
sendmsg(sock_fd, &msg, 0);
memset(nlh, 0, NLMSG_SPACE(MAX_PAYLOAD));
recvmsg(sock_fd, &msg, 0);
printf("Received message:\n%s\n", NLMSG_DATA(nlh));
usleep(1000);
}
close(sock_fd);
return (1);
}
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===================makefile如下===================：
MODULE_NAME :=net_link
obj-m :=$(MODULE_NAME).o
KERNELDIR ?= /lib/modules/$(shell uname -r)/build
PWD := $(shell pwd)
all:
$(MAKE) -C $(KERNELDIR) M=$(PWD)
gcc -o sender sender.c
clean:
rm -fr *.ko *.o *.cmd sender $(MODULE_NAME).mod.c
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[ 本帖最后由 duanjigang 于 2008-9-23 14:53 编辑 ] |
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发表于 2008-09-23 14:49
发表于 2008-09-23 14:57
