C语言获取Linux单网卡的多IP地址_嵌入式linux多个ip

2401_89190833

于 2025-01-11 22:15:12 发布

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文章标签： c语言 linux tcp/ip

本文链接：https://blog.youkuaiyun.com/2401_89190833/article/details/145083526

版权

TYPE=Ethernet
PROXY\_METHOD=none
BROWSER\_ONLY=no
BOOTPROTO=static
DEFROUTE=no
IPV4\_FAILURE\_FATAL=no
IPV6INIT=yes
IPV6\_AUTOCONF=yes
IPV6\_DEFROUTE=yes
IPV6\_FAILURE\_FATAL=no
IPV6\_ADDR\_GEN\_MODE=stable-privacy
NAME=p2p2
UUID=0a69226b-6051-4cb4-a1d3-17f37896275a
DEVICE=p2p2
ONBOOT=no
GATEWAY=192.168.11.1
IPADDR=192.168.11.111
NETMASK=255.255.255.0
DNS=114.114.114.114

我们直接在里面增加需要添加的IP，如下所示：

TYPE=Ethernet
PROXY\_METHOD=none
BROWSER\_ONLY=no
BOOTPROTO=static
DEFROUTE=no
IPV4\_FAILURE\_FATAL=no
IPV6INIT=yes
IPV6\_AUTOCONF=yes
IPV6\_DEFROUTE=yes
IPV6\_FAILURE\_FATAL=no
IPV6\_ADDR\_GEN\_MODE=stable-privacy
NAME=p2p2
UUID=0a69226b-6051-4cb4-a1d3-17f37896275a
DEVICE=p2p2
ONBOOT=no
GATEWAY=192.168.11.1
IPADDR=192.168.11.111
NETMASK=255.255.255.0
DNS=114.114.114.114
IPADDR2=192.168.11.11
GATEWAY2=192.168.11.1
NETMASK2=255.255.255.0
DNS2=114.114.114.114
IPADDR3=192.168.11.12
GATEWAY3=192.168.11.1
NETMASK3=255.255.255.0
DNS3=114.114.114.114

如上图，我们增加了两个IP，一个为192.168.11.11，一个为192.168.11.12。
保存后将网卡重新上线一下：

[root@ck10 chenyc]#ifdown p2p2
[root@ck10 chenyc]#ifup p2p2

完成后，从ifcofig是看不出来的：

[root@ck10 chenyc]# ifconfig p2p2
p2p2: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.11.111  netmask 255.255.255.0  broadcast 192.168.11.255
        inet6 fe80::cd7f:92f2:deb5:fb14  prefixlen 64  scopeid 0x20<link>
        ether 90:e2:ba:8f:06:41  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 232  bytes 47704 (46.5 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

但是用ip a命令可以看到已经生效：

7: p2p2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 90:e2:ba:8f:06:41 brd ff:ff:ff:ff:ff:ff
    inet 192.168.11.111/24 brd 192.168.11.255 scope global noprefixroute p2p2
       valid_lft forever preferred_lft forever
    inet 192.168.11.11/24 brd 192.168.11.255 scope global secondary noprefixroute p2p2
       valid_lft forever preferred_lft forever
    inet 192.168.11.12/24 brd 192.168.11.255 scope global secondary noprefixroute p2p2
       valid_lft forever preferred_lft forever
    inet6 fe80::cd7f:92f2:deb5:fb14/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

C代码实现

Linux 下获取单网卡的多IP实现方法有很多，我这里演示两种实现方法。

方法一

#include <stdio.h>
#include <stdlib.h>
#include <ifaddrs.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <linux/if.h>
#include<string.h>
int main(int argc, char \*\*argv) {
    struct ifaddrs \*ifaddr, \*ifa;
    if (getifaddrs(&ifaddr) == -1) {
        perror("getifaddrs");
        exit(EXIT_FAILURE);
    }

    for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
        if (ifa->ifa_addr == NULL) {
            continue;
        }
        if (strcmp(ifa->ifa_name, "p2p2") == 0 ){
                char ip[64] = {0};
                struct sockaddr\_in \*sock = ( struct sockaddr\_in\*)ifa->ifa_addr;
                inet\_ntop(AF_INET,&sock->sin_addr, ip, sizeof(ip));
                printf("name: %s, ip: %s\n", ifa->ifa_name, ip);
        }
    }

    freeifaddrs(ifaddr);
    exit(EXIT_SUCCESS);
}

第一种方法主要是利用getifaddrs函数获取到所有的网卡信息，这些信息会返回到一个 struct ifaddrs结构体中，该结构体本身是一个单向链表，结构如下所示：

            struct ifaddrs {
               struct ifaddrs  \*ifa_next;    /\* Next item in list \*/
               char            \*ifa_name;    /\* Name of interface \*/
               unsigned int     ifa_flags;   /\* Flags from SIOCGIFFLAGS \*/
               struct sockaddr \*ifa_addr;    /\* Address of interface \*/
               struct sockaddr \*ifa_netmask; /\* Netmask of interface \*/
               union {
                   struct sockaddr \*ifu_broadaddr;
                                    /\* Broadcast address of interface \*/
                   struct sockaddr \*ifu_dstaddr;
                                    /\* Point-to-point destination address \*/
               } ifa_ifu;
           #define ifa\_broadaddr ifa\_ifu.ifu\_broadaddr
           #define ifa\_dstaddr ifa\_ifu.ifu\_dstaddr
               void            \*ifa_data;    /\* Address-specific data \*/
           };

其中，ifa_next存储的是下一条网卡信息的地址，ifa_name存储的是网卡名，ifa_addr存储的就是IP地址。
不过这个函数会获取到一些冗余的信息，这些信息并不是我们所需要的，上面代码运行结果如下所示：

[root@ck10 chenyc]# ./1
name: p2p2, ip: 7.0.0.0
name: p2p2, ip: 192.168.11.111
name: p2p2, ip: 192.168.11.11
name: p2p2, ip: 192.168.11.12
name: p2p2, ip: 0.0.0.0

多了一个7.0.0.0和0.0.0.0。

方法二

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <malloc.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/ioctl.h>
#include <sys/types.h> 
#include <netinet/in.h> 
#include <arpa/inet.h> 
#include <linux/if.h>
#include<stdio.h> 
#define BUF\_SIZE 1024
 
int main()
{
    int sock_fd;
    struct ifconf conf;
    struct ifreq \*ifr;
    char buff[BUF_SIZE] = {0};
    int num;
    int i;
 
    sock_fd = socket(PF_INET, SOCK_DGRAM, 0);
    if ( sock_fd < 0 )     
        return -1;
    conf.ifc_len = BUF_SIZE;
    conf.ifc_buf = buff;
 
    if ( ioctl(sock_fd, SIOCGIFCONF, &conf) < 0 )
    {
        close(sock_fd);
        return -1;
    }
 
    num = conf.ifc_len / sizeof(struct ifreq);
    ifr = conf.ifc_req;