Linux/C + + to get network card IP by rule

Linux/C + + to get network card IP by rule

Output items to the cloud or output to external customers, will encounter the server multiple network card multiple IP situation, if there are many applications need this host IP, and multiple applications need to get the same IP, at this time can be agreed to a rule to get the same IP, such as: Get all the network card name, and then the network card name by small to large sort, Find the smallest network card name corresponding to the non-local IP, so that each application use this rule, you will get the same IP, and this idea is not limited by a variety of languages.

The detailed code is as follows:

#include <iostream> #include <stdio.h> #include <ifaddrs.h> #include <arpa/inet.h> #include

<string.h> #include <unistd.h> #include <stdlib.h> using namespace std;

int compare (const void *a,const void *b) {return strcmp (* (char * *) a,* (char * *) b);
    int Getsubnetmask (char ip[], int len) {struct sockaddr_in *sin = NULL;
    struct Ifaddrs *ifa = NULL, *iflist;
    String name[10];
    if (Getifaddrs (&iflist) < 0) {return-1;
    int i = 0; Find all network adapters and print the information for the NIC for (IFA = iflist IFA!= NULL; IFA = Ifa->ifa_next) {if (Ifa->ifa_addr->sa_fa
            Mily = = af_inet) {string ifname (ifa->ifa_name);
            Name[i]=ifname;
            i++;

            printf ("InterfaceName:%s\n", ifa->ifa_name);
            Sin = (struct sockaddr_in *) ifa->ifa_addr;

            printf ("IPAddress:%s\n", Inet_ntoa (SIN-&GT;SIN_ADDR)); Sin = (struct sockaddr_in *) IFA->ifa_dstaddr;

            printf ("Broadcast:%s\n", Inet_ntoa (SIN-&GT;SIN_ADDR));
            Sin = (struct sockaddr_in *) ifa->ifa_netmask;
        printf ("SubnetMask:%s\n\n", Inet_ntoa (SIN-&GT;SIN_ADDR)); }//Print all Non-empty network adapter name for (int i=0; i<sizeof (name)/sizeof (name[0)); i++) {if strcmp (Name[i].c_str ()
        , "")) {printf ("name%d=%s,", I,name[i].c_str ());
    printf ("\ n");
    From small to large sort qsort (name,10,sizeof (name[0]), compare);
        Find the IP for (int i=0; i<sizeof (name)/sizeof (Name[0]) of the minimum network card, i++) {if (strcmp (), "")) {for (IFA = iflist; IFA!= NULL; IFA = Ifa->ifa_next) {if (Ifa->ifa_add
                    r->sa_family = = af_inet) {string ifname (ifa->ifa_name); if (strcmp (Name[i].c_str (), ifname.c_str ()) = = 0) {printf ("Check name=%s\n", if NamE.c_str ());
                        Sin = (struct sockaddr_in *) ifa->ifa_addr;
                        Char *ipaddress = Inet_ntoa (SIN-&GT;SIN_ADDR);
                            Filter out the local if (strcmp (IPAddress, "127.0.0.1")) {
                            strncpy (Ip,ipaddress,len);
                            printf ("Last Use name=%s,ip=%s", Name[i].c_str (), IP);
                            Freeifaddrs (iflist);
                        return 0;
                        else {printf ("is");
    }}}}} Freeifaddrs (Iflist);
return-1;
    int main (int argc, char *argv[]) {char ip[64];
        if (int ret = getsubnetmask (ip,sizeof (IP)) < 0) {printf ("Find IP error\n");
    return-1;
    printf ("ip=%s\n", IP);
return 0; }