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#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <netdb.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <net/if_gre.h>
#define PORT 1013
/*great = gre auto tunnel*/
void dump(unsigned char *b,unsigned int t) {
for(;t;b++,t--) printf("%02x ",*b);
}
/* TODO:
args.
password?
clean out the extra shit.
clean it up even more.
arguments:
interface
listen-port
listen-addr
password?
*/
int main(int argc,char *argv[]) {
struct sockaddr_in sa;
struct sockaddr_in from;
char buf[512];
socklen_t sl=sizeof(struct sockaddr_in);
int so_link=socket(AF_LINK,SOCK_DGRAM,0);
int so_unspec=socket(AF_UNSPEC,SOCK_DGRAM,0);
int so_inet=socket(AF_INET,SOCK_DGRAM,0);
int so=socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
memset(&sa,0,(size_t)sizeof(struct sockaddr_in));
memset(&from,0,(size_t)sizeof(struct sockaddr_in));
sa.sin_addr.s_addr=inet_addr("192.168.0.2");
sa.sin_port=htons(PORT);
sa.sin_family=PF_INET;
bind(so,(struct sockaddr *)&sa,sizeof(sa));
recvfrom(so,buf,sizeof(buf),0,(struct sockaddr *)&from,&sl);
connect(so,(struct sockaddr *)&from,sl);
struct in_addr addr = {from.sin_addr.s_addr};
printf("%s\n",inet_ntoa(addr));
struct ifreq *asdf;
asdf=malloc(sizeof(struct ifreq));
memset(asdf,0,sizeof(struct ifreq));
strcpy(asdf->ifr_name,"gre10");
printf("destroy: %d\n",ioctl(so_link,SIOCIFDESTROY,asdf));//destroy
memset(asdf,0,sizeof(struct ifreq));
strcpy(asdf->ifr_name,"gre10");
printf("create: %d\n",ioctl(so_link,SIOCIFCREATE,asdf));//create
memset(asdf,0,sizeof(struct ifreq));
strcpy(asdf->ifr_name,"gre10");
asdf->ifr_flags=IPPROTO_UDP;
printf("proto: %d\n",ioctl(so_link,GRESPROTO,asdf));//link0 link2
memset(asdf,0,sizeof(struct ifreq));
strcpy(asdf->ifr_name,"gre10");
asdf->ifr_value=so;
printf("gressock: %d\n",ioctl(so_inet,GRESSOCK,asdf));//set socket
sleep(1);
system("ifconfig gre10");//just so you can see what it looks like.
return 0;
}
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