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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>
#include <linux/route.h>
static void die(const char *s)
{
fprintf(stderr,"error: %s (%s)\n", s, strerror(errno));
exit(-1);
}
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);
}
#define ADVANCE(argc, argv) do { argc--, argv++; } while(0)
#define EXPECT_NEXT(argc, argv) do { \
ADVANCE(argc, argv); \
if (0 == argc) { \
errno = EINVAL; \
die("expecting one more argument"); \
} \
} while(0)
/* current support two kinds of usage */
/* route add default dev wlan0 */
/* route add default gw 192.168.20.1 dev wlan0 */
int route_main(int argc, char *argv[])
{
struct ifreq ifr;
int s,i;
struct rtentry rt;
struct sockaddr_in ina;
if(argc == 0) return 0;
strncpy(ifr.ifr_name, argv[0], IFNAMSIZ);
ifr.ifr_name[IFNAMSIZ-1] = 0;
ADVANCE(argc, argv);
if((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
die("cannot open control socket\n");
}
while(argc > 0){
if(!strcmp(argv[0], "add")) {
EXPECT_NEXT(argc, argv);
if(!strcmp(argv[0], "default")) {
EXPECT_NEXT(argc, argv);
memset((char *) &rt, 0, sizeof(struct rtentry));
rt.rt_dst.sa_family = AF_INET;
if(!strcmp(argv[0], "dev")) {
EXPECT_NEXT(argc, argv);
rt.rt_flags = RTF_UP | RTF_HOST;
rt.rt_dev = argv[0];
if (ioctl(s, SIOCADDRT, &rt) < 0) die("SIOCADDRT");
}else if(!strcmp(argv[0], "gw")) {
EXPECT_NEXT(argc, argv);
rt.rt_flags = RTF_UP | RTF_GATEWAY;
init_sockaddr_in((struct sockaddr_in *)&(rt.rt_genmask), "0.0.0.0");
if(isdigit(argv[0][0])){
init_sockaddr_in((struct sockaddr_in *)&(rt.rt_gateway), argv[0]);
}else{
die("expecting an IP address for parameter \"gw\"");
}
EXPECT_NEXT(argc, argv);
if(!strcmp(argv[0], "dev")) {
EXPECT_NEXT(argc, argv);
rt.rt_dev = argv[0];
if (ioctl(s, SIOCADDRT, &rt) < 0){
die("SIOCADDRT");
}
}
}
}
}
ADVANCE(argc, argv);
}
return 0;
}
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