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Commit 88e97a93 authored by Gerrit Renker's avatar Gerrit Renker
Browse files

dccp ccid-3: Update the RX history records in one place 



This patch is a requirement for enabling ECN support later on. With that change
in mind, the following preparations are done:
 * renamed handle_loss() into congestion_event() since it returns true when a
   congestion event happens (it will eventually also take care of ECN packets);
 * lets tfrc_rx_congestion_event() always update the RX history records, since
   this routine needs to be called for each non-duplicate packet anyway;
 * made all involved boolean-type functions to have return type `bool';

Updating the RX history records is now only necessary for the packets received
up to sending the first feedback. The receiver code becomes again simpler.

Signed-off-by: default avatarGerrit Renker <gerrit@erg.abdn.ac.uk>
parent 68c89ee5

net/dccp/ccids/ccid3.c

+11 −26
Original line number Diff line number Diff line
@@ -657,41 +657,26 @@ failed: 
static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)

{

	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);

	enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE;

	const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp;

	const bool is_data_packet = dccp_data_packet(skb);



	/*

	 * Perform loss detection and handle pending losses

	 */

	if (tfrc_rx_handle_loss(&hcrx->hist, &hcrx->li_hist,

				skb, ndp, ccid3_first_li, sk)) {

		do_feedback = CCID3_FBACK_PARAM_CHANGE;

		goto done_receiving;

	}



	if (unlikely(hcrx->feedback == CCID3_FBACK_NONE)) {

		if (is_data_packet)

			do_feedback = CCID3_FBACK_INITIAL;

		goto update_records;

	}



	if (tfrc_rx_hist_loss_pending(&hcrx->hist))

		return; /* done receiving */



	if (tfrc_rx_congestion_event(&hcrx->hist, &hcrx->li_hist,

				     skb, ndp, ccid3_first_li, sk))

		ccid3_hc_rx_send_feedback(sk, skb, CCID3_FBACK_PARAM_CHANGE);

	/*

	 * Feedback for first non-empty data packet (RFC 3448, 6.3)

	 */

	else if (unlikely(hcrx->feedback == CCID3_FBACK_NONE && is_data_packet))

		ccid3_hc_rx_send_feedback(sk, skb, CCID3_FBACK_INITIAL);

	/*

	 * Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3

	 */

	if (is_data_packet &&

	else if (!tfrc_rx_hist_loss_pending(&hcrx->hist) && is_data_packet &&

		 SUB16(dccp_hdr(skb)->dccph_ccval, hcrx->last_counter) > 3)

		do_feedback = CCID3_FBACK_PERIODIC;



update_records:

	tfrc_rx_hist_add_packet(&hcrx->hist, skb, ndp);



done_receiving:

	if (do_feedback)

		ccid3_hc_rx_send_feedback(sk, skb, do_feedback);

		ccid3_hc_rx_send_feedback(sk, skb, CCID3_FBACK_PERIODIC);

}



static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)

net/dccp/ccids/lib/loss_interval.c

+5 −5
Original line number Diff line number Diff line
@@ -140,18 +140,18 @@ static inline u8 tfrc_lh_is_new_loss(struct tfrc_loss_interval *cur, 
 * @sk:		   Used by @calc_first_li in caller-specific way (subtyping)

 * Updates I_mean and returns 1 if a new interval has in fact been added to @lh.

 */

int tfrc_lh_interval_add(struct tfrc_loss_hist *lh, struct tfrc_rx_hist *rh,

bool tfrc_lh_interval_add(struct tfrc_loss_hist *lh, struct tfrc_rx_hist *rh,

			  u32 (*calc_first_li)(struct sock *), struct sock *sk)

{

	struct tfrc_loss_interval *cur = tfrc_lh_peek(lh), *new;



	if (cur != NULL && !tfrc_lh_is_new_loss(cur, tfrc_rx_hist_loss_prev(rh)))

		return 0;

		return false;



	new = tfrc_lh_demand_next(lh);

	if (unlikely(new == NULL)) {

		DCCP_CRIT("Cannot allocate/add loss record.");

		return 0;

		return false;

	}



	new->li_seqno	  = tfrc_rx_hist_loss_prev(rh)->tfrchrx_seqno;
@@ -169,7 +169,7 @@ int tfrc_lh_interval_add(struct tfrc_loss_hist *lh, struct tfrc_rx_hist *rh, 


		tfrc_lh_calc_i_mean(lh);

	}

	return 1;

	return true;

}

EXPORT_SYMBOL_GPL(tfrc_lh_interval_add);

net/dccp/ccids/lib/loss_interval.h

+1 −1
Original line number Diff line number Diff line
@@ -67,7 +67,7 @@ static inline u8 tfrc_lh_length(struct tfrc_loss_hist *lh) 


struct tfrc_rx_hist;



extern int  tfrc_lh_interval_add(struct tfrc_loss_hist *, struct tfrc_rx_hist *,

extern bool tfrc_lh_interval_add(struct tfrc_loss_hist *, struct tfrc_rx_hist *,

				 u32 (*first_li)(struct sock *), struct sock *);

extern void tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *);

extern void tfrc_lh_cleanup(struct tfrc_loss_hist *lh);

net/dccp/ccids/lib/packet_history.c

+18 −19
Original line number Diff line number Diff line
@@ -192,10 +192,8 @@ static void __do_track_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u64 n1) 
	u64 s0 = tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno,

	    s1 = DCCP_SKB_CB(skb)->dccpd_seq;



	if (!dccp_loss_free(s0, s1, n1)) {	/* gap between S0 and S1 */

	if (!dccp_loss_free(s0, s1, n1))	/* gap between S0 and S1 */

		h->loss_count = 1;

		tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 1), skb, n1);

	}

}



static void __one_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n2)
@@ -328,12 +326,12 @@ static void __three_after_loss(struct tfrc_rx_hist *h) 
}



/**

 *  tfrc_rx_handle_loss  -  Loss detection and further processing

 *  tfrc_rx_congestion_event  -  Loss detection and further processing

 *  @h:		The non-empty RX history object

 *  @lh:	Loss Intervals database to update

 *  @skb:	Currently received packet

 *  @ndp:	The NDP count belonging to @skb

 *  @calc_first_li: Caller-dependent computation of first loss interval in @lh

 *  @first_li:	Caller-dependent computation of first loss interval in @lh

 *  @sk:	Used by @calc_first_li (see tfrc_lh_interval_add)

 *  Chooses action according to pending loss, updates LI database when a new

 *  loss was detected, and does required post-processing. Returns 1 when caller
@@ -342,12 +340,12 @@ static void __three_after_loss(struct tfrc_rx_hist *h) 
 *  records accordingly, the caller should not perform any more RX history

 *  operations when loss_count is greater than 0 after calling this function.

 */

int tfrc_rx_handle_loss(struct tfrc_rx_hist *h,

bool tfrc_rx_congestion_event(struct tfrc_rx_hist *h,

			      struct tfrc_loss_hist *lh,

			      struct sk_buff *skb, const u64 ndp,

			u32 (*calc_first_li)(struct sock *), struct sock *sk)

			      u32 (*first_li)(struct sock *), struct sock *sk)

{

	int is_new_loss = 0;

	bool new_event = false;



	if (tfrc_rx_hist_duplicate(h, skb))

		return 0;
@@ -355,6 +353,7 @@ int tfrc_rx_handle_loss(struct tfrc_rx_hist *h, 
	if (h->loss_count == 0) {

		__do_track_loss(h, skb, ndp);

		tfrc_rx_hist_sample_rtt(h, skb);

		tfrc_rx_hist_add_packet(h, skb, ndp);

	} else if (h->loss_count == 1) {

		__one_after_loss(h, skb, ndp);

	} else if (h->loss_count != 2) {
@@ -363,7 +362,7 @@ int tfrc_rx_handle_loss(struct tfrc_rx_hist *h, 
		/*

		 * Update Loss Interval database and recycle RX records

		 */

		is_new_loss = tfrc_lh_interval_add(lh, h, calc_first_li, sk);

		new_event = tfrc_lh_interval_add(lh, h, first_li, sk);

		__three_after_loss(h);

	}
@@ -378,12 +377,12 @@ int tfrc_rx_handle_loss(struct tfrc_rx_hist *h, 
	}



	/* RFC 3448, 6.1: update I_0, whose growth implies p <= p_prev */

	if (!is_new_loss)

	if (!new_event)

		tfrc_lh_update_i_mean(lh, skb);



	return is_new_loss;

	return new_event;

}

EXPORT_SYMBOL_GPL(tfrc_rx_handle_loss);

EXPORT_SYMBOL_GPL(tfrc_rx_congestion_event);



/* Compute the sending rate X_recv measured between feedback intervals */

u32 tfrc_rx_hist_x_recv(struct tfrc_rx_hist *h, const u32 last_x_recv)

net/dccp/ccids/lib/packet_history.h

+5 −5
Original line number Diff line number Diff line
@@ -186,7 +186,7 @@ extern void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h, 
extern int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb);



struct tfrc_loss_hist;

extern int  tfrc_rx_handle_loss(struct tfrc_rx_hist *h,

extern bool tfrc_rx_congestion_event(struct tfrc_rx_hist *h,

				     struct tfrc_loss_hist *lh,

				     struct sk_buff *skb, const u64 ndp,

				     u32 (*first_li)(struct sock *sk),