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Date:	Tue, 1 Sep 2009 23:45:28 -0300
From:	Ivo Calado <ivocalado@...edded.ufcg.edu.br>
To:	dccp <dccp@...r.kernel.org>
Cc:	netdev <netdev@...r.kernel.org>
Subject: [PATCH 3/5] Implement TFRC-SP calc of mean length of loss intervals 
	accordingly to section 3 of RFC 4828

Implement TFRC-SP calc of mean length of loss intervals accordingly to
section 3 of RFC 4828

Changes:
 - Modify tfrc_sp_lh_calc_i_mean header, now receiving the current
ccval, so it can determine
  if a loss interval is too recent
 - Consider number of losses in each loss interval
 - Only consider open loss interval if it is at least 2 rtt old
 - Changes function signatures as necessary

Signed-off-by: Ivo Calado, Erivaldo Xavier, Leandro Sales
<ivocalado@...edded.ufcg.edu.br>, <desadoc@...il.com>,
<leandroal@...il.com>

Index: b/net/dccp/ccids/lib/loss_interval_sp.c
===================================================================
--- a/net/dccp/ccids/lib/loss_interval_sp.c     2009-08-26
23:28:27.000000000 -0300
+++ b/net/dccp/ccids/lib/loss_interval_sp.c     2009-08-26
23:53:32.000000000 -0300
@@ -66,10 +66,11 @@
               }
 }

-static void tfrc_sp_lh_calc_i_mean(struct tfrc_loss_hist *lh)
+static void tfrc_sp_lh_calc_i_mean(struct tfrc_loss_hist *lh, __u8 curr_ccval)
 {
       u32 i_i, i_tot0 = 0, i_tot1 = 0, w_tot = 0;
       int i, k = tfrc_lh_length(lh) - 1; /* k is as in rfc3448bis, 5.4 */
+       u32 losses;

       if (k <= 0)
               return;
@@ -77,6 +78,14 @@
       for (i = 0; i <= k; i++) {
               i_i = tfrc_lh_get_interval(lh, i);

+               if (SUB16(curr_ccval,
tfrc_lh_get_loss_interval(lh,i)->li_ccval) <= 8)
+               {
+                       losses = tfrc_lh_get_loss_interval(lh,i)->li_losses;
+
+                       if (losses > 0)
+                               i_i = div64_u64(i_i, losses);
+               }
+
               if (i < k) {
                       i_tot0 += i_i * tfrc_lh_weights[i];
                       w_tot  += tfrc_lh_weights[i];
@@ -86,6 +95,12 @@
       }

       lh->i_mean = max(i_tot0, i_tot1) / w_tot;
+       BUG_ON(w_tot == 0);
+       if (SUB16(curr_ccval, tfrc_lh_get_loss_interval(lh,0)->li_ccval) > 8) {
+               lh->i_mean = max(i_tot0, i_tot1) / w_tot;
+       } else {
+               lh->i_mean = i_tot1 / w_tot;
+       }
 }

 /**
@@ -126,7 +141,7 @@
               return;

       cur->li_length = len;
-       tfrc_sp_lh_calc_i_mean(lh);
+       tfrc_sp_lh_calc_i_mean(lh, dccp_hdr(skb)->dccph_ccval);
 }

 /* RFC 4342, 10.2: test for the existence of packet with sequence number S */
@@ -145,7 +160,7 @@
 * Updates I_mean and returns 1 if a new interval has in fact been
added to @lh.
 */
 bool tfrc_sp_lh_interval_add(struct tfrc_loss_hist *lh, struct
tfrc_rx_hist *rh,
-                            u32 (*calc_first_li)(struct sock *),
struct sock *sk)
+                            u32 (*calc_first_li)(struct sock *),
struct sock *sk, __u8 ccval)
 {
       struct tfrc_loss_interval *cur = tfrc_lh_peek(lh);
       struct tfrc_rx_hist_entry *cong_evt;
@@ -214,7 +229,7 @@
               if (lh->counter > (2*LIH_SIZE))
                       lh->counter -= LIH_SIZE;

-               tfrc_sp_lh_calc_i_mean(lh);
+               tfrc_sp_lh_calc_i_mean(lh, ccval);
       }

       return true;
Index: b/net/dccp/ccids/lib/loss_interval_sp.h
===================================================================
--- a/net/dccp/ccids/lib/loss_interval_sp.h     2009-08-26
22:52:20.000000000 -0300
+++ b/net/dccp/ccids/lib/loss_interval_sp.h     2009-08-26
23:44:20.000000000 -0300
@@ -71,7 +71,7 @@
 #endif

 extern bool tfrc_sp_lh_interval_add(struct tfrc_loss_hist *, struct
tfrc_rx_hist *,
-                                   u32 (*first_li)(struct sock *),
struct sock *);
+                                   u32 (*first_li)(struct sock *),
struct sock *, __u8 ccval);
 extern void tfrc_sp_lh_update_i_mean(struct tfrc_loss_hist *lh,
struct sk_buff *);
 extern void tfrc_sp_lh_cleanup(struct tfrc_loss_hist *lh);

Index: b/net/dccp/ccids/lib/packet_history_sp.c
===================================================================
--- a/net/dccp/ccids/lib/packet_history_sp.c    2009-08-26
22:55:01.000000000 -0300
+++ b/net/dccp/ccids/lib/packet_history_sp.c    2009-08-26
23:49:59.000000000 -0300
@@ -359,7 +359,7 @@
               /*
               * Update Loss Interval database and recycle RX records
               */
-               new_event = tfrc_sp_lh_interval_add(lh, h, first_li, sk);
+               new_event = tfrc_sp_lh_interval_add(lh, h, first_li, sk,
dccp_hdr(skb)->dccph_ccval);
               __three_after_loss(h);

       } else if (dccp_data_packet(skb) && dccp_skb_is_ecn_ce(skb)) {
@@ -368,7 +368,7 @@
               * the RFC considers ECN marks - a future implementation may
               * find it useful to also check ECN marks on non-data packets.
               */
-               new_event = tfrc_sp_lh_interval_add(lh, h, first_li, sk);
+               new_event = tfrc_sp_lh_interval_add(lh, h, first_li, sk,
dccp_hdr(skb)->dccph_ccval);
               /*
               * Also combinations of loss and ECN-marks (as per the warning)
               * are not supported. The permutations of loss combined with or
--
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