手动阀-如何获取网络连接状态？

要获取网络连接状态，您可以使用以下方法：，，1. 在Windows系统中，打开命令提示符并输入ping www.google.com。如果返回了四个响应，则表示您的网络连接正常。，，2. 在Mac或Linux系统中，打开终端并输入ping -c 4 www.google.com。如果返回了四个响应，则表示您的网络连接正常。，，3. 您还可以使用浏览器访问任何网站，如www.google.com，如果能成功加载页面，则表示您的网络连接正常。

在C语言中，获取网络连接状态可以通过调用系统提供的网络接口函数来实现，这些函数通常位于不同的操作系统平台上，因此需要根据具体的操作系统选择相应的API，以下是一些常见的方法：

如何获取网络连接状态？

1. 使用getifaddrs函数（适用于Linux和macOS）

getifaddrs函数可以获取本地主机的所有网络接口信息，包括IP地址、子网掩码等，通过解析这些信息，可以判断网络连接状态。

示例代码

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ifaddrs.h>
#include <netinet/in.h>
#include <arpa/inet.h>
int main() {
    struct ifaddrs *ifaddr, *ifa;
    int family, s;
    char host[NI_MAXHOST];
    if (getifaddrs(&ifaddr) == -1) {
        perror("getifaddrs");
        exit(EXIT_FAILURE);
    }
    // 遍历所有接口
    for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
        if (ifa->ifa_addr == NULL)
            continue;
        family = ifa->ifa_addr->sa_family;
        // 显示接口名称和家庭类型
        printf("%-8s %s (%d)
", ifa->ifa_name,
               (family == AF_PACKET) ? "AF_PACKET" :
               (family == AF_INET)  ? "AF_INET" :
               (family == AF_INET6) ? "AF_INET6" : "???", family);
        // 对于IPv4地址，显示IP地址
        if (family == AF_INET || family == AF_INET6) {
            s = getnameinfo(ifa->ifa_addr,
                           (family == AF_INET) ? sizeof(struct sockaddr_in) :
                           sizeof(struct sockaddr_in6),
                           host, NI_MAXHOST, NULL, 0, NI_NUMERICHOST);
            if (s != 0) {
                printf("getnameinfo() failed: %s
", gai_strerror(s));
                exit(EXIT_FAILURE);
            }
            printf("\taddress: <%s>
", host);
        } else if (family == AF_PACKET && ifa->ifa_data != NULL) {
            struct sockaddr_ll *s = (struct sockaddr_ll *)ifa->ifa_addr;
            printf("\taddress: <%d:%d:%d:%d:%d:%d>
",
                   s->sll_addr[0], s->sll_addr[1], s->sll_addr[2],
                   s->sll_addr[3], s->sll_addr[4], s->sll_addr[5]);
        }
    }
    freeifaddrs(ifaddr);
    exit(EXIT_SUCCESS);
}

2. 使用Windows API（适用于Windows）

在Windows平台上，可以使用GetAdaptersAddresses或GetAdaptersInfo函数来获取网络适配器的信息，以下是一个使用GetAdaptersAddresses的例子：

示例代码

#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>
// Link with ws2_32.lib
#pragma comment(lib, "Ws2_32.lib")
int main() {
    ULONG outBufLen = 0;
    DWORD dwRetVal = 0;
    LPIP_ADAPTER_ADDRESSES pAddresses = NULL;
    LPIP_ADAPTER_ADDRESSES pCurrAddresses = NULL;
    // Determine the size of the buffer required to hold the data
    dwRetVal = GetAdaptersAddresses(AF_UNSPEC, GAA_FLAG_INCLUDE_PREFIX, NULL, NULL, &outBufLen);
    if (dwRetVal == ERROR_BUFFER_OVERFLOW) {
        // Allocate memory for the adapter addresses
        pAddresses = (IP_ADAPTER_ADDRESSES *) malloc(outBufLen);
        if (pAddresses == NULL) {
            printf("Error allocating memory needed to call GetAdaptersAddresses
");
            return 1;
        }
        // Make a second call to actually retrieve the data
        dwRetVal = GetAdaptersAddresses(AF_UNSPEC, GAA_FLAG_INCLUDE_PREFIX, NULL, pAddresses, &outBufLen);
    }
    if (dwRetVal == NO_ERROR) {
        // Iterate through the list of adapters and print their information
        for (pCurrAddresses = pAddresses; pCurrAddresses != NULL; pCurrAddresses = pCurrAddresses->Next) {
            printf("Adapter Name: %S
", pCurrAddresses->FriendlyName);
            printf("Description: %S
", pCurrAddresses->Description);
            printf("MAC Address: %02X-%02X-%02X-%02X-%02X-%02X
",
                   pCurrAddresses->PhysicalAddress[0], pCurrAddresses->PhysicalAddress[1],
                   pCurrAddresses->PhysicalAddress[2], pCurrAddresses->PhysicalAddress[3],
                   pCurrAddresses->PhysicalAddress[4], pCurrAddresses->PhysicalAddress[5]);
            // Display IP address information for each unicast address associated with the adapter
            for (IP_ADAPTER_UNICAST_ADDRESS *pUnicast = pCurrAddresses->FirstUnicastAddress; pUnicast != NULL; pUnicast = pUnicast->Next) {
                char str[INET6_ADDRSTRLEN];
                if (pUnicast->Address.lpSockaddr->sa_family == AF_INET) { // IPv4
                    getnameinfo(pUnicast->Address.lpSockaddr, pUnicast->Address.lpSockaddr->sa_family == AF_INET ? sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6), str, NI_NUMERICHOST);
                    printf("\tIPv4 Address: %s
", str);
                } else if (pUnicast->Address.lpSockaddr->sa_family == AF_INET6) { // IPv6
                    getnameinfo(pUnicast->Address.lpSockaddr, pUnicast->Address.lpSockaddr->sa_family == AF_INET ? sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6), str, NI_NUMERICHOST);
                    printf("\tIPv6 Address: %s
", str);
                }
            }
        }
        free(pAddresses);
    } else {
        printf("Call to GetAdaptersAddresses failed with error: %d
", dwRetVal);
    }
    return 0;
}

3. 使用BSD socket API（适用于BSD风格的系统，如FreeBSD）

在BSD风格的系统中，可以使用ioctl和getsockopt等函数来获取网络连接状态，可以使用SIOCGIFFLAGS命令来获取接口的标志位，从而判断是否启用了接口。

示例代码

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <unistd.h>
void print_interface_status(const char *interface) {
    int sockfd;
    struct ifreq ifr;
    struct ifconf ifc;
    char buf[1024]; // Adjust size as necessary
    ifc.ifc_len = sizeof(buf);
    ifc.ifc_buf = buf;
    ifc.ifc_req = NULL; // No specific request, just probe all interfaces
    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sockfd == -1) {
        perror("socket");
        return;
    }
    if (ioctl(sockfd, SIOCGIFCONF, &ifc) == -1) {
        perror("ioctl");
        close(sockfd);
        return;
    }
    struct ifreq *iter = ifc.ifc_req;
    while (iter != NULL) {
        if (!strcmp(iter->ifr_name, interface)) {
            if (ioctl(sockfd, SIOCGIFFLAGS, iter) == -1) {
                perror("ioctl");
            } else {
                printf("%s is %s
", interface, (iter->ifr_flags & IFF_UP) ? "UP" : "DOWN");
            }
            break;
        }
        iter = (struct ifreq *)((char *)iter + sizeof(struct ifreq));
    }
    close(sockfd);
}
int main() {
    print_interface_status("eth0"); // 替换为实际的网络接口名称
    return 0;
}

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手动阀

Good Luck To You!

如何获取网络连接状态？2024-12-02 18:25:21

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