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#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <linux/if.h>
#include <linux/sockios.h>
#include <arpa/inet.h>
static void die(const char *s)
{
fprintf(stderr,"error: %s (%s)\n", s, strerror(errno));
exit(-1);
}
static void setflags(int s, struct ifreq *ifr, int set, int clr)
{
if(ioctl(s, SIOCGIFFLAGS, ifr) < 0) die("SIOCGIFFLAGS");
ifr->ifr_flags = (ifr->ifr_flags & (~clr)) | set;
if(ioctl(s, SIOCSIFFLAGS, ifr) < 0) die("SIOCSIFFLAGS");
}
static inline void init_sockaddr_in(struct sockaddr_in *sin, const char *addr)
{
sin->sin_family = AF_INET;
sin->sin_port = 0;
sin->sin_addr.s_addr = inet_addr(addr);
}
static void setmtu(int s, struct ifreq *ifr, const char *mtu)
{
int m = atoi(mtu);
ifr->ifr_mtu = m;
if(ioctl(s, SIOCSIFMTU, ifr) < 0) die("SIOCSIFMTU");
}
static void setdstaddr(int s, struct ifreq *ifr, const char *addr)
{
init_sockaddr_in((struct sockaddr_in *) &ifr->ifr_dstaddr, addr);
if(ioctl(s, SIOCSIFDSTADDR, ifr) < 0) die("SIOCSIFDSTADDR");
}
static void setnetmask(int s, struct ifreq *ifr, const char *addr)
{
init_sockaddr_in((struct sockaddr_in *) &ifr->ifr_netmask, addr);
if(ioctl(s, SIOCSIFNETMASK, ifr) < 0) die("SIOCSIFNETMASK");
}
static void setaddr(int s, struct ifreq *ifr, const char *addr)
{
init_sockaddr_in((struct sockaddr_in *) &ifr->ifr_addr, addr);
if(ioctl(s, SIOCSIFADDR, ifr) < 0) die("SIOCSIFADDR");
}
int ifconfig_main(int argc, char *argv[])
{
struct ifreq ifr;
int s;
unsigned int addr, mask, flags;
char astring[20];
char mstring[20];
char *updown, *brdcst, *loopbk, *ppp, *running, *multi;
argc--;
argv++;
if(argc == 0) return 0;
memset(&ifr, 0, sizeof(struct ifreq));
strncpy(ifr.ifr_name, argv[0], IFNAMSIZ);
ifr.ifr_name[IFNAMSIZ-1] = 0;
argc--, argv++;
if((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
die("cannot open control socket\n");
}
if (argc == 0) {
if (ioctl(s, SIOCGIFADDR, &ifr) < 0) {
perror(ifr.ifr_name);
return -1;
} else
addr = ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr.s_addr;
if (ioctl(s, SIOCGIFNETMASK, &ifr) < 0) {
perror(ifr.ifr_name);
return -1;
} else
mask = ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr.s_addr;
if (ioctl(s, SIOCGIFFLAGS, &ifr) < 0) {
perror(ifr.ifr_name);
return -1;
} else
flags = ifr.ifr_flags;
sprintf(astring, "%d.%d.%d.%d",
addr & 0xff,
((addr >> 8) & 0xff),
((addr >> 16) & 0xff),
((addr >> 24) & 0xff));
sprintf(mstring, "%d.%d.%d.%d",
mask & 0xff,
((mask >> 8) & 0xff),
((mask >> 16) & 0xff),
((mask >> 24) & 0xff));
printf("%s: ip %s mask %s flags [", ifr.ifr_name,
astring,
mstring
);
updown = (flags & IFF_UP) ? "up" : "down";
brdcst = (flags & IFF_BROADCAST) ? " broadcast" : "";
loopbk = (flags & IFF_LOOPBACK) ? " loopback" : "";
ppp = (flags & IFF_POINTOPOINT) ? " point-to-point" : "";
running = (flags & IFF_RUNNING) ? " running" : "";
multi = (flags & IFF_MULTICAST) ? " multicast" : "";
printf("%s%s%s%s%s%s]\n", updown, brdcst, loopbk, ppp, running, multi);
return 0;
}
while(argc > 0) {
if (!strcmp(argv[0], "up")) {
setflags(s, &ifr, IFF_UP, 0);
} else if (!strcmp(argv[0], "mtu")) {
argc--, argv++;
if (!argc) {
errno = EINVAL;
die("expecting a value for parameter \"mtu\"");
}
setmtu(s, &ifr, argv[0]);
} else if (!strcmp(argv[0], "-pointopoint")) {
setflags(s, &ifr, IFF_POINTOPOINT, 1);
} else if (!strcmp(argv[0], "pointopoint")) {
argc--, argv++;
if (!argc) {
errno = EINVAL;
die("expecting an IP address for parameter \"pointtopoint\"");
}
setdstaddr(s, &ifr, argv[0]);
setflags(s, &ifr, IFF_POINTOPOINT, 0);
} else if (!strcmp(argv[0], "down")) {
setflags(s, &ifr, 0, IFF_UP);
} else if (!strcmp(argv[0], "netmask")) {
argc--, argv++;
if (!argc) {
errno = EINVAL;
die("expecting an IP address for parameter \"netmask\"");
}
setnetmask(s, &ifr, argv[0]);
} else if (isdigit(argv[0][0])) {
setaddr(s, &ifr, argv[0]);
setflags(s, &ifr, IFF_UP, 0);
}
argc--, argv++;
}
return 0;
}
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