获取网卡ip地址代码实现

#include <iostream>
#include <map>
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <ifaddrs.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <netdb.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/socket.h>
void PaddingSpecNetInfoByName(const char *szDevName, std::map<std::string, std::string> &netMap)
{
    int s = socket(AF_INET, SOCK_DGRAM, 0);
    if (s < 0)
    {
        fprintf(stderr, "Create socket failed!errno=%d", errno);
        return;
    }
    struct ifreq ifr;
    unsigned char mac[6];
    unsigned long nIP, nNetmask, nBroadIP;
    std::string netName = std::string(szDevName);
    // printf("name : %s \n", szDevName);
    auto iter = netMap.find(netName);
    if (iter == netMap.end())
    {
        strcpy(ifr.ifr_name, szDevName);
        if (ioctl(s, SIOCGIFADDR, &ifr) < 0)
        {
            nIP = 0;
        }
        else
        {
            nIP = *(unsigned long *)&ifr.ifr_broadaddr.sa_data[2];
        }
        printf("IP addr: %s \n", inet_ntoa(*(in_addr *)&nIP));
        netMap.insert(make_pair(netName, std::string(inet_ntoa(*(in_addr *)&nIP))));
    }
    close(s);
}
void GetCurrentNetCardInfo(std::map<std::string, std::string> &netMap)
{
    FILE *f = fopen("/proc/net/dev", "r");
    if (!f)
    {
        fprintf(stderr, "Open /proc/net/dev failed!errno:%dn", errno);
        return;
    }
    char szLine[512];
    fgets(szLine, sizeof(szLine), f);
    fgets(szLine, sizeof(szLine), f);
    while (fgets(szLine, sizeof(szLine), f))
    {
        char szName[128] = {0};
        sscanf(szLine, "%s", szName);
        int nLen = strlen(szName);
        if (nLen <= 0)
            continue;
        if (szName[nLen - 1] == ':')
            szName[nLen - 1] = 0;
        std::string netName = std::string(szName);
        // printf("name : %s \n", szName);
        if ((netName.find("eth") != std::string::npos) || (netName.find("en") != std::string::npos))
        {
            PaddingSpecNetInfoByName(szName, netMap);
        }
    }
    fclose(f);
    f = NULL;
}
int main()
{
  std::map<std::string, std::string> curMap;
  GetCurrentNetCardInfo(curMap);
    return 0;
}