void schedule_and_send(int link){
if(links[link].timeout_occurred == false)
return;
//printf("QUEUE SIZES for link %d: %d(a) %d(s) %d(f)\n", link, queue_nitems(links[link].ack_sender), queue_nitems(links[link].sender), queue_nitems(links[link].forwarding_queue));
//Send ack if it is there -- TOP PRIORITY
if(queue_nitems(links[link].ack_sender) > 0){
send_acks(link);
return;
}
//If ack queue is empty send packets from sender queue OR forwarding queue in priority basis
if(queue_nitems(links[link].forwarding_queue) == 0 && queue_nitems(links[link].sender) > 0){
send_frames(link);
}
else if (queue_nitems(links[link].forwarding_queue) > 0 && queue_nitems(links[link].sender) == 0){
forward_frames(link);
}
else if (queue_nitems(links[link].forwarding_queue) == 0 && queue_nitems(links[link].sender) == 0){
return;
}
else {
links[link].packet_to_send = (links[link].packet_to_send + 1) % (PRIORITY + 1);
//printf("packet to send is ----------------------------------------- %d\n", links[link].packet_to_send);
//if(links[link].packet_to_send == PRIORITY)
if(queue_nitems(links[link].forwarding_queue) > queue_nitems(links[link].sender))
//send forwarding
forward_frames(link);
else
//send normal
send_frames(link);
}
}
static int process_haves_and_send_acks(struct upload_pack_data *data)
{
struct oid_array common = OID_ARRAY_INIT;
struct strbuf response = STRBUF_INIT;
int ret = 0;
process_haves(&data->haves, &common);
if (data->done) {
ret = 1;
} else if (send_acks(&common, &response)) {
packet_buf_delim(&response);
ret = 1;
} else {
/* Add Flush */
packet_buf_flush(&response);
ret = 0;
}
/* Send response */
write_or_die(1, response.buf, response.len);
strbuf_release(&response);
oid_array_clear(&data->haves);
oid_array_clear(&common);
return ret;
}
int main(int argc, char *argv[])
{
unsigned int port;
int opt;
unsigned long delay;
pid_t pid;
char *interface, *endptr;
char libnet_ebuf[LIBNET_ERRBUF_SIZE];
pcap_t *pcap;
char pcap_expr[100];
libnet_t *libnet;
u_int32_t target_addr, source_addr;
struct sigaction sa;
interface = NULL;
while ((opt = getopt(argc, argv, "i:")) != -1) {
switch (opt) {
case 'i':
interface = optarg;
break;
default:
usage();
break;
}
}
argc -= optind;
argv += optind;
if (argc != 3) {
usage();
}
port = strtoul(argv[1], &endptr, 10);
if ((*endptr != '\0') || port < 1 || port > 65535) {
errx(1, "Invalid port: %s", argv[1]);
}
errno = 0;
delay = strtoul(argv[2], &endptr, 10);
if (*endptr != '\0') {
errx(1, "invalid delay: %s", argv[2]);
} else if ((errno == ERANGE &&
(delay == LONG_MAX)) ||
(errno != 0 && delay == 0)) {
errx(1, "invalid delay (%s): %s", strerror(errno), argv[2]);
}
/* Initialize libnet */
if ((libnet = libnet_init(LIBNET_RAW4, interface, libnet_ebuf)) == NULL) {
errx(1, "couldn't initialize libnet: %s", libnet_ebuf);
}
if ((target_addr = libnet_name2addr4(libnet, argv[0], LIBNET_RESOLVE)) == -1) {
errx(1, "could not resolve target %s", argv[0]);
}
if ((source_addr = libnet_get_ipaddr4(libnet)) == -1) {
errx(1, "could not get local IP: %s", libnet_ebuf);
}
/* Initialize pcap */
snprintf(pcap_expr, 99, "tcp and tcp[tcpflags] == 18 and src host %s and port %s",
argv[0], argv[1]);
if ((pcap = pcap_init(interface, pcap_expr, 64)) == NULL)
errx(1, "couldn't initialize sniffing");
if ((pcap_off = pcap_dloff(pcap)) < 0)
errx(1, "couldn't determine link layer offset");
/* Fork */
pid = fork();
if (pid == -1)
errx(1, "fork failed");
else if (pid == 0)
send_syns(libnet, source_addr, target_addr, port, delay);
else {
child_pid = pid;
sa.sa_handler = &handle_signal;
sigaction(SIGINT, &sa, NULL);
sigaction(SIGQUIT, &sa, NULL);
sigaction(SIGTERM, &sa, NULL);
send_acks(pcap, libnet);
}
return EXIT_SUCCESS;
}
