ccid3.c

linux2.6.16版本

	case TFRC_SSTATE_FBACK:
		if (len > 0) {
			hctx->ccid3hctx_t_nom = now;
			ccid3_calc_new_t_ipi(hctx);
			ccid3_calc_new_delta(hctx);
			timeval_add_usecs(&hctx->ccid3hctx_t_nom,
					  hctx->ccid3hctx_t_ipi);
		}
		break;
	default:
		printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
		       __FUNCTION__, dccp_role(sk), sk, hctx->ccid3hctx_state);
		dump_stack();
		break;
	}
}

static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
{
	const struct dccp_sock *dp = dccp_sk(sk);
	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
	struct ccid3_options_received *opt_recv;
	struct dccp_tx_hist_entry *packet;
	struct timeval now;
	unsigned long next_tmout; 
	u32 t_elapsed;
	u32 pinv;
	u32 x_recv;
	u32 r_sample;

	BUG_ON(hctx == NULL || hctx->ccid3hctx_state == TFRC_SSTATE_TERM);

	/* we are only interested in ACKs */
	if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
	      DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
		return;

	opt_recv = &hctx->ccid3hctx_options_received;

	t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
	x_recv = opt_recv->ccid3or_receive_rate;
	pinv = opt_recv->ccid3or_loss_event_rate;

	switch (hctx->ccid3hctx_state) {
	case TFRC_SSTATE_NO_SENT:
		/* FIXME: what to do here? */
		return;
	case TFRC_SSTATE_NO_FBACK:
	case TFRC_SSTATE_FBACK:
		/* Calculate new round trip sample by
		 * R_sample = (now - t_recvdata) - t_delay */
		/* get t_recvdata from history */
		packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
						 DCCP_SKB_CB(skb)->dccpd_ack_seq);
		if (unlikely(packet == NULL)) {
			LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, seqno "
				       "%llu(%s) does't exist in history!\n",
				       __FUNCTION__, dccp_role(sk), sk,
			    (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
				dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
			return;
		}

		/* Update RTT */
		dccp_timestamp(sk, &now);
		r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
		if (unlikely(r_sample <= t_elapsed))
			LIMIT_NETDEBUG(KERN_WARNING "%s: r_sample=%uus, "
				       "t_elapsed=%uus\n",
				       __FUNCTION__, r_sample, t_elapsed);
		else
			r_sample -= t_elapsed;

		/* Update RTT estimate by 
		 * If (No feedback recv)
		 *    R = R_sample;
		 * Else
		 *    R = q * R + (1 - q) * R_sample;
		 *
		 * q is a constant, RFC 3448 recomments 0.9
		 */
		if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
			ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
			hctx->ccid3hctx_rtt = r_sample;
		} else
			hctx->ccid3hctx_rtt = (hctx->ccid3hctx_rtt * 9) / 10 +
					      r_sample / 10;

		ccid3_pr_debug("%s, sk=%p, New RTT estimate=%uus, "
			       "r_sample=%us\n", dccp_role(sk), sk,
			       hctx->ccid3hctx_rtt, r_sample);

		/* Update timeout interval */
		hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
					      USEC_PER_SEC);

		/* Update receive rate */
		hctx->ccid3hctx_x_recv = x_recv;/* X_recv in bytes per sec */

		/* Update loss event rate */
		if (pinv == ~0 || pinv == 0)
			hctx->ccid3hctx_p = 0;
		else {
			hctx->ccid3hctx_p = 1000000 / pinv;

			if (hctx->ccid3hctx_p < TFRC_SMALLEST_P) {
				hctx->ccid3hctx_p = TFRC_SMALLEST_P;
				ccid3_pr_debug("%s, sk=%p, Smallest p used!\n",
					       dccp_role(sk), sk);
			}
		}

		/* unschedule no feedback timer */
		sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);

		/* Update sending rate */
		ccid3_hc_tx_update_x(sk);

		/* Update next send time */
		timeval_sub_usecs(&hctx->ccid3hctx_t_nom,
				  hctx->ccid3hctx_t_ipi);
		ccid3_calc_new_t_ipi(hctx);
		timeval_add_usecs(&hctx->ccid3hctx_t_nom,
				  hctx->ccid3hctx_t_ipi);
		ccid3_calc_new_delta(hctx);

		/* remove all packets older than the one acked from history */
		dccp_tx_hist_purge_older(ccid3_tx_hist,
					 &hctx->ccid3hctx_hist, packet);
		/*
		 * As we have calculated new ipi, delta, t_nom it is possible that
		 * we now can send a packet, so wake up dccp_wait_for_ccids.
		 */
		sk->sk_write_space(sk);

		/*
		 * Schedule no feedback timer to expire in
		 * max(4 * R, 2 * s / X)
		 */
		next_tmout = max(hctx->ccid3hctx_t_rto,
				 2 * usecs_div(hctx->ccid3hctx_s,
					       hctx->ccid3hctx_x));
			
		ccid3_pr_debug("%s, sk=%p, Scheduled no feedback timer to "
			       "expire in %lu jiffies (%luus)\n",
			       dccp_role(sk), sk,
			       usecs_to_jiffies(next_tmout), next_tmout); 

		sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer, 
			       jiffies + max_t(u32, 1, usecs_to_jiffies(next_tmout)));

		/* set idle flag */
		hctx->ccid3hctx_idle = 1;   
		break;
	default:
		printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
		       __FUNCTION__, dccp_role(sk), sk, hctx->ccid3hctx_state);
		dump_stack();
		break;
	}
}

static void ccid3_hc_tx_insert_options(struct sock *sk, struct sk_buff *skb)
{
	const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);

	BUG_ON(hctx == NULL);

	if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
		return;

	 DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
}

static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
				     unsigned char len, u16 idx,
				     unsigned char *value)
{
	int rc = 0;
	const struct dccp_sock *dp = dccp_sk(sk);
	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
	struct ccid3_options_received *opt_recv;

	BUG_ON(hctx == NULL);

	opt_recv = &hctx->ccid3hctx_options_received;

	if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
		opt_recv->ccid3or_seqno		     = dp->dccps_gsr;
		opt_recv->ccid3or_loss_event_rate    = ~0;
		opt_recv->ccid3or_loss_intervals_idx = 0;
		opt_recv->ccid3or_loss_intervals_len = 0;
		opt_recv->ccid3or_receive_rate	     = 0;
	}

	switch (option) {
	case TFRC_OPT_LOSS_EVENT_RATE:
		if (unlikely(len != 4)) {
			LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, invalid "
				       "len for TFRC_OPT_LOSS_EVENT_RATE\n",
				       __FUNCTION__, dccp_role(sk), sk);
			rc = -EINVAL;
		} else {
			opt_recv->ccid3or_loss_event_rate = ntohl(*(u32 *)value);
			ccid3_pr_debug("%s, sk=%p, LOSS_EVENT_RATE=%u\n",
				       dccp_role(sk), sk,
				       opt_recv->ccid3or_loss_event_rate);
		}
		break;
	case TFRC_OPT_LOSS_INTERVALS:
		opt_recv->ccid3or_loss_intervals_idx = idx;
		opt_recv->ccid3or_loss_intervals_len = len;
		ccid3_pr_debug("%s, sk=%p, LOSS_INTERVALS=(%u, %u)\n",
			       dccp_role(sk), sk,
			       opt_recv->ccid3or_loss_intervals_idx,
			       opt_recv->ccid3or_loss_intervals_len);
		break;
	case TFRC_OPT_RECEIVE_RATE:
		if (unlikely(len != 4)) {
			LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, invalid "
				       "len for TFRC_OPT_RECEIVE_RATE\n",
				       __FUNCTION__, dccp_role(sk), sk);
			rc = -EINVAL;
		} else {
			opt_recv->ccid3or_receive_rate = ntohl(*(u32 *)value);
			ccid3_pr_debug("%s, sk=%p, RECEIVE_RATE=%u\n",
				       dccp_role(sk), sk,
				       opt_recv->ccid3or_receive_rate);
		}
		break;
	}

	return rc;
}

static int ccid3_hc_tx_init(struct sock *sk)
{
	struct dccp_sock *dp = dccp_sk(sk);
	struct ccid3_hc_tx_sock *hctx;

	dp->dccps_hc_tx_ccid_private = kmalloc(sizeof(*hctx), gfp_any());
	if (dp->dccps_hc_tx_ccid_private == NULL)
		return -ENOMEM;

	hctx = ccid3_hc_tx_sk(sk);
	memset(hctx, 0, sizeof(*hctx));

	if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
	    dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
		hctx->ccid3hctx_s = dp->dccps_packet_size;
	else
		hctx->ccid3hctx_s = TFRC_STD_PACKET_SIZE;

	/* Set transmission rate to 1 packet per second */
	hctx->ccid3hctx_x     = hctx->ccid3hctx_s;
	hctx->ccid3hctx_t_rto = USEC_PER_SEC;
	hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
	INIT_LIST_HEAD(&hctx->ccid3hctx_hist);
	init_timer(&hctx->ccid3hctx_no_feedback_timer);

	return 0;
}

static void ccid3_hc_tx_exit(struct sock *sk)
{
	struct dccp_sock *dp = dccp_sk(sk);
	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);

	BUG_ON(hctx == NULL);

	ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
	sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);

	/* Empty packet history */
	dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);

	kfree(dp->dccps_hc_tx_ccid_private);
	dp->dccps_hc_tx_ccid_private = NULL;
}

/*
 * RX Half Connection methods
 */

/* TFRC receiver states */
enum ccid3_hc_rx_states {
       	TFRC_RSTATE_NO_DATA = 1,
	TFRC_RSTATE_DATA,
	TFRC_RSTATE_TERM    = 127,
};

#ifdef CCID3_DEBUG
static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
{
	static char *ccid3_rx_state_names[] = {
	[TFRC_RSTATE_NO_DATA] = "NO_DATA",
	[TFRC_RSTATE_DATA]    = "DATA",
	[TFRC_RSTATE_TERM]    = "TERM",
	};

	return ccid3_rx_state_names[state];
}
#endif

static inline void ccid3_hc_rx_set_state(struct sock *sk,
					 enum ccid3_hc_rx_states state)
{
	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
	enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;

	ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
		       dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
		       ccid3_rx_state_name(state));
	WARN_ON(state == oldstate);
	hcrx->ccid3hcrx_state = state;
}

static void ccid3_hc_rx_send_feedback(struct sock *sk)
{
	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
	struct dccp_sock *dp = dccp_sk(sk);
	struct dccp_rx_hist_entry *packet;
	struct timeval now;

	ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);

	dccp_timestamp(sk, &now);

	switch (hcrx->ccid3hcrx_state) {
	case TFRC_RSTATE_NO_DATA:
		hcrx->ccid3hcrx_x_recv = 0;
		break;
	case TFRC_RSTATE_DATA: {
		const u32 delta = timeval_delta(&now,
					&hcrx->ccid3hcrx_tstamp_last_feedback);
		hcrx->ccid3hcrx_x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv,
						   delta);
	}
		break;
	default:
		printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
		       __FUNCTION__, dccp_role(sk), sk, hcrx->ccid3hcrx_state);
		dump_stack();
		return;
	}

	packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
	if (unlikely(packet == NULL)) {
		LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, no data packet "
			       "in history!\n",
			       __FUNCTION__, dccp_role(sk), sk);
		return;
	}

	hcrx->ccid3hcrx_tstamp_last_feedback = now;
	hcrx->ccid3hcrx_last_counter	     = packet->dccphrx_ccval;
	hcrx->ccid3hcrx_seqno_last_counter   = packet->dccphrx_seqno;
	hcrx->ccid3hcrx_bytes_recv	     = 0;

	/* Convert to multiples of 10us */
	hcrx->ccid3hcrx_elapsed_time =
			timeval_delta(&now, &packet->dccphrx_tstamp) / 10;
	if (hcrx->ccid3hcrx_p == 0)
		hcrx->ccid3hcrx_pinv = ~0;
	else
		hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
	dp->dccps_hc_rx_insert_options = 1;
	dccp_send_ack(sk);
}

static void ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
{
	const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
	u32 x_recv, pinv;

	BUG_ON(hcrx == NULL);

	if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
		return;

	DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_last_counter;

	if (dccp_packet_without_ack(skb))
		return;
		
	if (hcrx->ccid3hcrx_elapsed_time != 0)
		dccp_insert_option_elapsed_time(sk, skb,
						hcrx->ccid3hcrx_elapsed_time);
	dccp_insert_option_timestamp(sk, skb);
	x_recv = htonl(hcrx->ccid3hcrx_x_recv);
	pinv   = htonl(hcrx->ccid3hcrx_pinv);
	dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
			   &pinv, sizeof(pinv));
	dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
			   &x_recv, sizeof(x_recv));
}

/* calculate first loss interval
 *
 * returns estimated loss interval in usecs */

static u32 ccid3_hc_rx_calc_first_li(struct sock *sk)
{
	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
	struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
	u32 rtt, delta, x_recv, fval, p, tmp2;
	struct timeval tstamp = { 0, };
	int interval = 0;
	int win_count = 0;
	int step = 0;
	u64 tmp1;

	list_for_each_entry_safe(entry, next, &hcrx->ccid3hcrx_hist,
				 dccphrx_node) {
		if (dccp_rx_hist_entry_data_packet(entry)) {
			tail = entry;

			switch (step) {
			case 0:
				tstamp	  = entry->dccphrx_tstamp;
				win_count = entry->dccphrx_ccval;
				step = 1;
				break;
			case 1:
				interval = win_count - entry->dccphrx_ccval;