Very Computer

Now how do i do to get the interface address(aliases also).i have
written a small program, but dont know where iam going wrong.the code
is

#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <net/if.h>
#include <netinet/in.h>

int
main(int argc, char* argv[])
{
    struct ifconf ifc;
    struct ifreq *ifr;
    struct sockaddr_in *sin;
    char buf[128];

    if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        perror("socket");
        return 1;
    }

    ifc.ifc_buf = buf;
    ifc.ifc_len = sizeof(buf);
    if (ioctl(s, SIOCGIFCONF, &ifc) < 0) {
        perror("ioctl SIOCGIFCONF");
        return 1;
    }

    ifc.ifc_len /= sizeof(struct ifreq);
    for (i=0; i<ifc.ifc_len; i++) {
        ifr = (struct ifreq *) &ifc.ifc_req[i];
        sin = (struct sockaddr_in *) &ifr->ifr_addr;
        printf("%s \n",sin->sin_addr);
        }
    }
    return 0;

Quote:}

any help will be highly appreciated.

thanks
rohit

SW

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Quote:> there is another structure
> struct ifreq
> but i dont think i need that one.
[...]
>         ifr = (struct ifreq *) &ifc.ifc_req[i];

int main()
{
        int fd,i, j = 0;

        if (0 > (fd = socket(AF_INET, SOCK_DGRAM,0))) {
               perror("socket");
               exit(errno);
        }

        ifc.ifc_len = sizeof(buf);
        ifc.ifc_req = buf;

        if(ioctl(fd,SIOCGIFCONF,&ifc) == -1)
        {
                perror("ioctl");
                exit(errno);
        }

        ifc.ifc_len /= sizeof(struct ifreq);
        for (i=0; i<ifc.ifc_len; i++)
        {
                interface = (struct sockaddr_in *)&buf[i].ifr_addr;
                printf("\nInteface name == [%s]\n",
buf[i].ifr_ifrn.ifrn_name);
                printf("IP Addr ==
[%s]\n",inet_ntoa(interface->sin_addr));
        }

        return 0;

Quote:}

thanks for ur help and support
rohit

rohit> Now i also want to retrieve the default gateway.how do i get
rohit> that.can u please specify if there are some ioctls(if any) and
rohit> the relevent structures and how to use them.

IMO the best way to look for this (and the interface information, too)
is to read the files under /proc

especially /proc/net/dev, /proc/net/route

Of course this is completely nonportable - but so are the ioctls.

--
Ian Zimmerman, Oakland, California, U.S.A.
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