+ case 'p':
+ port = atoi(optarg);
+ break;
+ case 'o':
+ do_listen = 0;
+ break;
+ case -1:
+ return; // end of argument list
+ default:
+ fprintf(stderr, "Invalid option\n");
+ exit(1);
+ }
+ }
+}
+
+struct sender {
+ int fd;
+ unsigned long long bytes_left;
+};
+
+void generate_new_sender(int ep_fd, struct sender *s)
+{
+ int sock, one = 1;
+ unsigned src_num, dst_num;
+ unsigned long long num_bytes;
+ struct sockaddr_in sin;
+ struct epoll_event ev;
+
+ sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
+ if (sock == -1) {
+ perror("socket()");
+ exit(1);
+ }
+
+ // find the right parameters
+ src_num = (unsigned)(num_sources * gen_uniform_random());
+ dst_num = (unsigned)(num_destinations * gen_uniform_random());
+ num_bytes = (unsigned)gen_pareto_random(1048576.0, 1.0);
+
+ // FIXME: bind to the right source
+
+ if (ioctl(sock, FIONBIO, &one) == -1) {
+ perror("FIONBIO");
+ exit(1);
+ }
+
+ sin.sin_family = AF_INET;
+ sin.sin_port = htons(port);
+ sin.sin_addr = destinations[dst_num];
+
+ // non-blocking connect (will be detected by epoll later)
+ if (connect(sock, (struct sockaddr *)&sin, sizeof(sin)) == -1 && errno != EINPROGRESS) {
+ perror("connect()");
+ exit(1);
+ }
+
+ // stick it in the epoll set (FIXME: make edge-triggered?)
+ ev.events = EPOLLOUT | EPOLLHUP | EPOLLERR;
+ ev.data.ptr = s;
+
+ s->fd = sock;
+ s->bytes_left = num_bytes;
+
+ if (epoll_ctl(ep_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
+ perror("EPOLL_CTL_ADD");
+ exit(1);
+ }
+}
+
+void *sender_worker(void *arg)
+{
+ unsigned i;
+ char buf[65536];
+ unsigned long long bytes_sent = 0;
+ int ep_fd;
+ struct epoll_event *events;
+
+ ep_fd = epoll_create(num_sockets_per_sender);
+ if (ep_fd == -1) {
+ perror("epoll_create");
+ exit(1);
+ }
+
+ // malloc, since there might not be enough room on the stack
+ events = (struct epoll_event *)malloc(sizeof(struct epoll_event) * num_sockets_per_sender);
+ if (events == NULL) {
+ perror("malloc");
+ exit(1);
+ }
+
+ // fill the buffer with random junk
+ for (i = 0; i < 65536; ++i)
+ buf[i] = rand() & 0xff;
+
+ // allocate all the senders
+ for (i = 0; i < num_sockets_per_sender; ++i) {
+ struct sender *s = (struct sender *)malloc(sizeof(struct sender));
+ if (s == NULL) {
+ perror("malloc()");
+ exit(1);
+ }
+
+ generate_new_sender(ep_fd, s);
+ }
+
+ for ( ;; ) {
+ int num_active = epoll_wait(ep_fd, events, num_sockets_per_sender, -1);
+ if (num_active == -1) {
+ if (errno == EINTR)
+ continue;
+ perror("epoll_wait");
+ exit(1);
+ }
+
+ for (i = 0; i < num_active; ++i) {
+ struct sender *s = (struct sender *)events[i].data.ptr;
+ unsigned long long bytes_to_send = s->bytes_left;
+ unsigned ret;
+
+ if (bytes_to_send > 65536) {
+ bytes_to_send = 65536;
+ }
+
+ ret = send(s->fd, buf, bytes_to_send, MSG_NOSIGNAL);
+ if (ret == -1) {
+ if (errno == EAGAIN || errno == EINTR)
+ continue;
+
+ perror("send()");
+ exit(1);
+ }
+
+ s->bytes_left -= ret;
+ bytes_sent += ret;
+
+ // update the central counter after every 1MB (8ms
+ // at gigabit speeds, should be enough) of sent data
+ if (bytes_sent > update_frequency) {
+ pthread_mutex_lock(&send_mutex);
+ total_bytes_sent += bytes_sent;
+ pthread_mutex_unlock(&send_mutex);
+
+ bytes_sent = 0;
+ }
+
+ if (s->bytes_left == 0) {
+ if (epoll_ctl(ep_fd, EPOLL_CTL_DEL, s->fd, NULL) == -1) {
+ perror("EPOLL_CTL_DEL");
+ exit(1);
+ }
+ close(s->fd);
+ generate_new_sender(ep_fd, s);
+ }
+ }
+ }