Inserting values in functions using getopt_long
Hi,
I'm trying to create a program that will be able to send tcp packets using raw sockets. In order to do so I need to pass values like ip-addresses and port numbers to the send_tcp function, but I do not know how using getopt_long.
Code:
int main(int argc,char **argv)
{
int c;
/* Are we in root? */
if(geteuid() !=0)
{
printf("Root access is required to run this program.\n\n");
exit(0);
}
while (1)
{
static struct option long_options[] =
{
/* Options */
{"send", no_argument, 0, 's'}, /* args s and r have no function yet */
{"recieve", no_argument, 0, 'r'},
{"file", required_argument, 0, 'f'},
{"destip", required_argument, 0, 'i'},
{"destport", required_argument, 0, 'p'},
{"sourceip", required_argument, 0, 'o'},
{"sourceport", required_argument, 0, 't'},
{0, 0, 0, 0}
};
int option_index = 0;
c = getopt_long (argc, argv, "srf:d:i:p:o:t:",
long_options, &option_index);
/* Detect the end of the options. */
if (c == -1)
break;
switch (c)
{
case 0:
/* If this option set a flag, do nothing else now. */
if (long_options[option_index].flag != 0)
break;
printf ("option %s", long_options[option_index].name);
if (optarg)
printf (" with arg %s", optarg);
printf ("\n");
break;
case 's':
puts ("option -s\n");
break;
case 'r':
puts ("option -r\n");
break;
case 'f':
printf ("option -f with value `%s'\n", optarg);
break;
case 'i':
printf ("option -i with value `%s'\n", optarg);
break;
case 'p':
printf ("option -p with value `%s'\n", optarg);
break;
case 'o':
printf ("option -o with value `%s'\n", optarg);
break;
case 't':
printf ("option -t with value `%s'\n", optarg);
break;
case '?':
/* Error message printed */
break;
default:
abort ();
}
}
/* Print any remaining command line arguments (not options). */
if (optind < argc)
{
printf ("non-option ARGV-elements: ");
while (optind < argc)
printf ("%s ", argv[optind++]);
putchar ('\n');
}
forgepacket(sourceip, destip, sourceport, destport, file);
getchar ();
exit (0);
}
int send_tcp()
{
int sock, one = 1;
char buffer[PCKT_LEN];
struct sockaddr_in, sin, din;
const int *val = &one;
sock = socket(PF_INET, SOCK_RAW, IPPROTO_TCP);
if (sock < 0)
{
printf("\nError: socket()\n\n");
exit (-1);
}
else
printf ("\nsocket() - Using SOCK_RAW and TCP protocol is OK.\n\n");
/* Size of the headers */
struct ipheader *ip = (struct ipheader *) buffer;
struct tcpheader *tcp = (struct tcpheader *) (buffer + sizeof (struct ipheader));
memset (buffer, 0, PCKT_LEN);
/* IP attributes */
ip->iph_ihl = 5;
ip->iph_ver = 4;
ip->iph_tos = 16;
ip->iph_len = sizeof(struct ipheader) + sizeof(struct tcpheader);
ip->iph_id = htons(54321);
ip->iph_offset = 0;
ip->iph_ttl = 64;
ip->iph_protocol = 6;
ip->iph_chksum = 0;
ip->iph_sourceip = inet_addr(???);
ip->iph_destip = inet_addr(???);
/* TCP attributes */
tcp->tcph_sourceport = htons(atoi(???));
tcp->tcph_destport = htons(atoi(???));
tcp->tcph_seqnum = htonl(1);
tcp->tcph_acknum = 0;
tcp->tcph_offset = 5;
tcp->tcph_syn = 1;
tcp->tcph_ack = 0;
tcp->tcph_win = htons(32767);
tcp->tcph_chksum = 0;
tcp->tcph_urgptr = 0;
ip->iph_chksum = checksum ((unsigned short *) buffer, (sizeof (struct ipheader )+ sizeof (struct tcpheader)));
/* Address family */
sin.sin_family = AF_INET;
din.sin_family = AF_INET;
/* Source port */
sin.sin_port = htons(atoi(???));
din.sin_port = htons(atoi(???));
/* Source IP */
sin.sin_addr.s_addr = inet_addr(???);
din.sin_addr.s_addr = inet_addr(???);
}
I've placed 3 question marks where I believe something needs to be added, but to be honest I haven't got a clue, despite active googling. The printf statements in the various cases obviously needs changing to, but as I've said, I'm stumped.
Any suggestions?