0.概要

本文介绍用C语言编写一个函数来获取本机的IP地址。

1. 设计

将获取IP地址的逻辑封装到一个独立的函数中，并定义一个结构体来存储IP地址和接口名称。
将获取IP地址的逻辑封装到一个函数中，该函数遍历本机的所有网络接口并获取其IP地址.

2. 完整的代码

完整的代码如下：

ip_address.h

#ifndef IP_ADDRESS_H
#define IP_ADDRESS_H#include <netinet/in.h>
#include <net/if.h>#define MAX_IP_ADDRESSES 50
#define INET6_ADDRSTRLEN 46typedef struct {char ifa_name[IFNAMSIZ];char ip_address[INET6_ADDRSTRLEN];int family;
} IPAddress;int get_ip_addresses(IPAddress *ip_addresses, int max_addresses);#endif // IP_ADDRESS_H

ip_address.c

#include "ip_address.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ifaddrs.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if.h>int get_ip_addresses(IPAddress *ip_addresses, int max_addresses) {struct ifaddrs *ifAddrStruct = NULL;struct ifaddrs *ifa = NULL;void *tmpAddrPtr = NULL;int count = 0;if (getifaddrs(&ifAddrStruct) == -1) {/* Error handling */return -1;}for (ifa = ifAddrStruct; ifa != NULL && count < max_addresses; ifa = ifa->ifa_next) {if (ifa->ifa_addr == NULL) {continue;}int family = ifa->ifa_addr->sa_family;if (family == AF_INET) {tmpAddrPtr = &((struct sockaddr_in *)(ifa->ifa_addr))->sin_addr;if (inet_ntop(AF_INET, tmpAddrPtr, ip_addresses[count].ip_address, INET_ADDRSTRLEN) != NULL) {strncpy(ip_addresses[count].ifa_name, ifa->ifa_name, IFNAMSIZ);ip_addresses[count].family = AF_INET;count++;}} else if (family == AF_INET6) {tmpAddrPtr = &((struct sockaddr_in6 *)(ifa->ifa_addr))->sin6_addr;if (inet_ntop(AF_INET6, tmpAddrPtr, ip_addresses[count].ip_address, INET6_ADDRSTRLEN) != NULL) {strncpy(ip_addresses[count].ifa_name, ifa->ifa_name, IFNAMSIZ);ip_addresses[count].family = AF_INET6;count++;}} else {/* Do nothing */}}freeifaddrs(ifAddrStruct);return count;
}

main.c

#include <stdio.h>
#include "ip_address.h"int main(void) {IPAddress ip_addresses[MAX_IP_ADDRESSES];int count = get_ip_addresses(ip_addresses, MAX_IP_ADDRESSES);if (count == -1) {fprintf(stderr, "Failed to get IP addresses.\n");return 1;}for (int i = 0; i < count; i++) {if (ip_addresses[i].family == AF_INET) {printf("%s IPv4 Address: %s\n", ip_addresses[i].ifa_name, ip_addresses[i].ip_address);} else if (ip_addresses[i].family == AF_INET6) {printf("%s IPv6 Address: %s\n", ip_addresses[i].ifa_name, ip_addresses[i].ip_address);}}return 0;
}

编译命令

gcc -o ip_address main.c ip_address.c

执行结果

test@t:~/ip_address$ ./ip_address 
lo IPv4 Address: 127.0.0.1
ens33 IPv4 Address: 192.168.1.10
lo IPv6 Address: ::1
ens33 IPv6 Address: 2409:8a20:4e3c:d460:20c:29ff:feb3:d386
ens33 IPv6 Address: fe80::20c:29ff:feb3:d386

通过上述步骤，你将能够获取并打印本机的所有IPv4和IPv6地址。