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virtual_interface.c
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virtual_interface.c
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/*
dcmp denial_of_service program.
march 2019
by wang zih_min
*/
#include "virtual_interface.h"
#include "dhcp_protocol.h"
char interface[IFNAMSIZ]={0};
int main(int argc,char **argv){
if(argc!=3){
fprintf(stderr,"usage: ./virtual_interface <name of a connected interface> <i (hwmac + i)>\n");
exit(-1);
}
if(strlen(argv[1])>=IFNAMSIZ){
fprintf(stderr,"interface name too long\n");
exit(-1);
}
//Copy interface name to a global variable.
memcpy(interface,argv[1],IFNAMSIZ);
int hwmac_increment=atoi(argv[2]);
while(1){
char command[128]={0};
int len=0;//len is the total length of command in the end,excluding of terminator.
char byte=0;
while(read(STDIN_FILENO,&byte,1)>0){
if(byte=='\n') break;
assert(len<127);//the last byte of command is always null.
command[len]=byte;
len+=1;
}
int kill_flag=0;
char * pch;
char command_cp[128];
memcpy(command_cp,command,128);
pch = strtok(command," ");
while (pch != NULL)
{
//pch is the first command
if(strcmp(pch,"kill")==0){
kill_flag=1;//terminate this virtual interface.
}
else if(strcmp(pch,"DHCP")==0){
dhcp_protocol(command_cp,hwmac_increment);
}
else if(0){
//put supported protocol at here.
}
else{
send_fd("doesn't support this protocol\n");
}
break;//only read the first command
}
if(kill_flag==1){
send_fd("terminating\n");
break;
}
}
return 0;
}
static void send_fd(char *s){
write(STDOUT_FILENO, s, strlen(s));
}