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Commit cc0a910b authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo Committed by David S. Miller
Browse files

[DCCP] loss_interval: Move ccid3_hc_rx_update_li to loss_interval 



Renaming it to dccp_li_update_li.

Also based on previous work by Ian McDonald.

Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@ghostprotocols.net>
parent 878ac600

net/dccp/ccids/ccid3.c

+9 −170
Original line number Diff line number Diff line
@@ -819,167 +819,6 @@ static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb) 
	return 0;

}



/* calculate first loss interval

 *

 * returns estimated loss interval in usecs */



static u32 ccid3_hc_rx_calc_first_li(struct sock *sk,

				     struct list_head *hist_list,

				     struct timeval *last_feedback,

				     u16 s, u32 bytes_recv,

				     u32 previous_x_recv)

{

	struct dccp_rx_hist_entry *entry, *next, *tail = NULL;

	u32 x_recv, p;

	suseconds_t rtt, delta;

	struct timeval tstamp = { 0, 0 };

	int interval = 0;

	int win_count = 0;

	int step = 0;

	u64 fval;



	list_for_each_entry_safe(entry, next, hist_list, 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;

				if (interval < 0)

					interval += TFRC_WIN_COUNT_LIMIT;

				if (interval > 4)

					goto found;

				break;

			}

		}

	}



	if (unlikely(step == 0)) {

		DCCP_WARN("%s(%p), packet history has no data packets!\n",

			  dccp_role(sk), sk);

		return ~0;

	}



	if (unlikely(interval == 0)) {

		DCCP_WARN("%s(%p), Could not find a win_count interval > 0."

			  "Defaulting to 1\n", dccp_role(sk), sk);

		interval = 1;

	}

found:

	if (!tail) {

		DCCP_CRIT("tail is null\n");

		return ~0;

	}



	delta = timeval_delta(&tstamp, &tail->dccphrx_tstamp);

	DCCP_BUG_ON(delta < 0);



	rtt = delta * 4 / interval;

	ccid3_pr_debug("%s(%p), approximated RTT to %dus\n",

		       dccp_role(sk), sk, (int)rtt);



	/*

	 * Determine the length of the first loss interval via inverse lookup.

	 * Assume that X_recv can be computed by the throughput equation

	 *		    s

	 *	X_recv = --------

	 *		 R * fval

	 * Find some p such that f(p) = fval; return 1/p [RFC 3448, 6.3.1].

	 */

	if (rtt == 0) {			/* would result in divide-by-zero */

		DCCP_WARN("RTT==0\n");

		return ~0;

	}



	dccp_timestamp(sk, &tstamp);

	delta = timeval_delta(&tstamp, last_feedback);

	DCCP_BUG_ON(delta <= 0);



	x_recv = scaled_div32(bytes_recv, delta);

	if (x_recv == 0) {		/* would also trigger divide-by-zero */

		DCCP_WARN("X_recv==0\n");

		if (previous_x_recv == 0) {

			DCCP_BUG("stored value of X_recv is zero");

			return ~0;

		}

		x_recv = previous_x_recv;

	}



	fval = scaled_div(s, rtt);

	fval = scaled_div32(fval, x_recv);

	p = tfrc_calc_x_reverse_lookup(fval);



	ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied "

		       "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);



	if (p == 0)

		return ~0;

	else

		return 1000000 / p;

}



static void ccid3_hc_rx_update_li(struct sock *sk,

				  struct dccp_li_hist *li_hist,

				  struct list_head *li_hist_list,

				  struct list_head *hist_list,

				  struct timeval *last_feedback,

				  u16 s, u32 bytes_recv,

				  u32 previous_x_recv,

				  u64 seq_loss, u8 win_loss)

{

	struct dccp_li_hist_entry *head;

	u64 seq_temp;



	if (list_empty(li_hist_list)) {

		if (!dccp_li_hist_interval_new(li_hist, li_hist_list,

					       seq_loss, win_loss))

			return;



		head = list_entry(li_hist_list->next, struct dccp_li_hist_entry,

				  dccplih_node);

		head->dccplih_interval =

				ccid3_hc_rx_calc_first_li(sk, hist_list,

							  last_feedback, s,

							  bytes_recv,

							  previous_x_recv);

	} else {

		struct dccp_li_hist_entry *entry;

		struct list_head *tail;



		head = list_entry(li_hist_list->next, struct dccp_li_hist_entry,

				  dccplih_node);

		/* FIXME win count check removed as was wrong */

		/* should make this check with receive history */

		/* and compare there as per section 10.2 of RFC4342 */



		/* new loss event detected */

		/* calculate last interval length */

		seq_temp = dccp_delta_seqno(head->dccplih_seqno, seq_loss);

		entry = dccp_li_hist_entry_new(li_hist, GFP_ATOMIC);



		if (entry == NULL) {

			DCCP_BUG("out of memory - can not allocate entry");

			return;

		}



		list_add(&entry->dccplih_node, li_hist_list);



		tail = li_hist_list->prev;

		list_del(tail);

		kmem_cache_free(li_hist->dccplih_slab, tail);



		/* Create the newest interval */

		entry->dccplih_seqno = seq_loss;

		entry->dccplih_interval = seq_temp;

		entry->dccplih_win_count = win_loss;

	}

}



static int ccid3_hc_rx_detect_loss(struct sock *sk,

				    struct dccp_rx_hist_entry *packet)

{
@@ -1005,7 +844,7 @@ static int ccid3_hc_rx_detect_loss(struct sock *sk, 
	while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno)

	   > TFRC_RECV_NUM_LATE_LOSS) {

		loss = 1;

		ccid3_hc_rx_update_li(sk, ccid3_li_hist,

		dccp_li_update_li(sk, ccid3_li_hist,

				  &hcrx->ccid3hcrx_li_hist,

				  &hcrx->ccid3hcrx_hist,

				  &hcrx->ccid3hcrx_tstamp_last_feedback,

net/dccp/ccids/lib/loss_interval.c

+160 −0
Original line number Diff line number Diff line
@@ -15,6 +15,8 @@ 
#include <net/sock.h>

#include "../../dccp.h"

#include "loss_interval.h"

#include "packet_history.h"

#include "tfrc.h"



struct dccp_li_hist *dccp_li_hist_new(const char *name)

{
@@ -141,3 +143,161 @@ int dccp_li_hist_interval_new(struct dccp_li_hist *hist, 
}



EXPORT_SYMBOL_GPL(dccp_li_hist_interval_new);



/* calculate first loss interval

 *

 * returns estimated loss interval in usecs */

static u32 dccp_li_calc_first_li(struct sock *sk,

				 struct list_head *hist_list,

				 struct timeval *last_feedback,

				 u16 s, u32 bytes_recv,

				 u32 previous_x_recv)

{

	struct dccp_rx_hist_entry *entry, *next, *tail = NULL;

	u32 x_recv, p;

	suseconds_t rtt, delta;

	struct timeval tstamp = { 0, 0 };

	int interval = 0;

	int win_count = 0;

	int step = 0;

	u64 fval;



	list_for_each_entry_safe(entry, next, hist_list, 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;

				if (interval < 0)

					interval += TFRC_WIN_COUNT_LIMIT;

				if (interval > 4)

					goto found;

				break;

			}

		}

	}



	if (unlikely(step == 0)) {

		DCCP_WARN("%s(%p), packet history has no data packets!\n",

			  dccp_role(sk), sk);

		return ~0;

	}



	if (unlikely(interval == 0)) {

		DCCP_WARN("%s(%p), Could not find a win_count interval > 0."

			  "Defaulting to 1\n", dccp_role(sk), sk);

		interval = 1;

	}

found:

	if (!tail) {

		DCCP_CRIT("tail is null\n");

		return ~0;

	}



	delta = timeval_delta(&tstamp, &tail->dccphrx_tstamp);

	DCCP_BUG_ON(delta < 0);



	rtt = delta * 4 / interval;

	dccp_pr_debug("%s(%p), approximated RTT to %dus\n",

		      dccp_role(sk), sk, (int)rtt);



	/*

	 * Determine the length of the first loss interval via inverse lookup.

	 * Assume that X_recv can be computed by the throughput equation

	 *		    s

	 *	X_recv = --------

	 *		 R * fval

	 * Find some p such that f(p) = fval; return 1/p [RFC 3448, 6.3.1].

	 */

	if (rtt == 0) {			/* would result in divide-by-zero */

		DCCP_WARN("RTT==0\n");

		return ~0;

	}



	dccp_timestamp(sk, &tstamp);

	delta = timeval_delta(&tstamp, last_feedback);

	DCCP_BUG_ON(delta <= 0);



	x_recv = scaled_div32(bytes_recv, delta);

	if (x_recv == 0) {		/* would also trigger divide-by-zero */

		DCCP_WARN("X_recv==0\n");

		if (previous_x_recv == 0) {

			DCCP_BUG("stored value of X_recv is zero");

			return ~0;

		}

		x_recv = previous_x_recv;

	}



	fval = scaled_div(s, rtt);

	fval = scaled_div32(fval, x_recv);

	p = tfrc_calc_x_reverse_lookup(fval);



	dccp_pr_debug("%s(%p), receive rate=%u bytes/s, implied "

		      "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);



	if (p == 0)

		return ~0;

	else

		return 1000000 / p;

}



void dccp_li_update_li(struct sock *sk, struct dccp_li_hist *li_hist,

		       struct list_head *li_hist_list,

		       struct list_head *hist_list,

		       struct timeval *last_feedback, u16 s, u32 bytes_recv,

                       u32 previous_x_recv, u64 seq_loss, u8 win_loss)

{

	struct dccp_li_hist_entry *head;

	u64 seq_temp;



	if (list_empty(li_hist_list)) {

		if (!dccp_li_hist_interval_new(li_hist, li_hist_list,

					       seq_loss, win_loss))

			return;



		head = list_entry(li_hist_list->next, struct dccp_li_hist_entry,

				  dccplih_node);

		head->dccplih_interval = dccp_li_calc_first_li(sk, hist_list,

							       last_feedback,

							       s, bytes_recv,

							       previous_x_recv);

	} else {

		struct dccp_li_hist_entry *entry;

		struct list_head *tail;



		head = list_entry(li_hist_list->next, struct dccp_li_hist_entry,

				  dccplih_node);

		/* FIXME win count check removed as was wrong */

		/* should make this check with receive history */

		/* and compare there as per section 10.2 of RFC4342 */



		/* new loss event detected */

		/* calculate last interval length */

		seq_temp = dccp_delta_seqno(head->dccplih_seqno, seq_loss);

		entry = dccp_li_hist_entry_new(li_hist, GFP_ATOMIC);



		if (entry == NULL) {

			DCCP_BUG("out of memory - can not allocate entry");

			return;

		}



		list_add(&entry->dccplih_node, li_hist_list);



		tail = li_hist_list->prev;

		list_del(tail);

		kmem_cache_free(li_hist->dccplih_slab, tail);



		/* Create the newest interval */

		entry->dccplih_seqno = seq_loss;

		entry->dccplih_interval = seq_temp;

		entry->dccplih_win_count = win_loss;

	}

}



EXPORT_SYMBOL_GPL(dccp_li_update_li);

net/dccp/ccids/lib/loss_interval.h

+7 −0
Original line number Diff line number Diff line
@@ -54,4 +54,11 @@ extern u32 dccp_li_hist_calc_i_mean(struct list_head *list); 


extern int dccp_li_hist_interval_new(struct dccp_li_hist *hist,

   struct list_head *list, const u64 seq_loss, const u8 win_loss);



extern void dccp_li_update_li(struct sock *sk, struct dccp_li_hist *li_hist,

			      struct list_head *li_hist_list,

			      struct list_head *hist_list,

			      struct timeval *last_feedback, u16 s,

			      u32 bytes_recv, u32 previous_x_recv,

			      u64 seq_loss, u8 win_loss);

#endif /* _DCCP_LI_HIST_ */