Implement loss counting on TFRC-SP receiver. Consider transmission's hole size as loss count.
Changes:
- Adds field li_losses to tfrc_loss_interval to track loss count per interval
- Adds field num_losses to tfrc_rx_hist, used to store loss count per loss event
- Adds dccp_loss_count function to net/dccp/dccp.h, responsible for loss count using sequence numbers
Signed-off-by: Ivo Calado <ivocalado@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Erivaldo Xavier <desadoc@xxxxxxxxx>
Signed-off-by: Leandro Sales <leandroal@xxxxxxxxx>
Index: dccp_tree_work03/net/dccp/ccids/lib/loss_interval_sp.c
===================================================================
--- dccp_tree_work03.orig/net/dccp/ccids/lib/loss_interval_sp.c 2009-10-08 22:54:16.819408361 -0300
+++ dccp_tree_work03/net/dccp/ccids/lib/loss_interval_sp.c 2009-10-08 22:59:07.439908552 -0300
@@ -183,8 +183,11 @@
if (len <= 0)
return false;
- if (!tfrc_lh_closed_check(cur, cong_evt->tfrchrx_ccval))
+ if (!tfrc_lh_closed_check(cur, cong_evt->tfrchrx_ccval)) {
+ cur->li_losses += rh->num_losses;
+ rh->num_losses = 0;
return false;
+ }
/* RFC 5348, 5.3: length between subsequent intervals */
cur->li_length = len;
@@ -200,6 +203,8 @@
cur->li_seqno = cong_evt_seqno;
cur->li_ccval = cong_evt->tfrchrx_ccval;
cur->li_is_closed = false;
+ cur->li_losses = rh->num_losses;
+ rh->num_losses = 0;
if (++lh->counter == 1)
lh->i_mean = cur->li_length = (*calc_first_li)(sk);
Index: dccp_tree_work03/net/dccp/ccids/lib/loss_interval_sp.h
===================================================================
--- dccp_tree_work03.orig/net/dccp/ccids/lib/loss_interval_sp.h 2009-10-08 22:54:16.838907787 -0300
+++ dccp_tree_work03/net/dccp/ccids/lib/loss_interval_sp.h 2009-10-08 22:59:07.439908552 -0300
@@ -30,12 +30,14 @@
* @li_ccval: The CCVal belonging to @li_seqno
* @li_is_closed: Whether @li_seqno is older than 1 RTT
* @li_length: Loss interval sequence length
+ * @li_losses: Number of losses counted on this interval
*/
struct tfrc_loss_interval {
u64 li_seqno:48,
li_ccval:4,
li_is_closed:1;
u32 li_length;
+ u32 li_losses;
};
/**
Index: dccp_tree_work03/net/dccp/ccids/lib/packet_history_sp.h
===================================================================
--- dccp_tree_work03.orig/net/dccp/ccids/lib/packet_history_sp.h 2009-10-08 22:58:53.134907870 -0300
+++ dccp_tree_work03/net/dccp/ccids/lib/packet_history_sp.h 2009-10-08 22:59:07.439908552 -0300
@@ -104,6 +104,7 @@
* @packet_size: Packet size in bytes (as per RFC 3448, 3.1)
* @bytes_recvd: Number of bytes received since @bytes_start
* @bytes_start: Start time for counting @bytes_recvd
+ * @num_losses: Number of losses detected
*/
struct tfrc_rx_hist {
struct tfrc_rx_hist_entry *ring[TFRC_NDUPACK + 1];
@@ -116,6 +117,7 @@
u32 packet_size,
bytes_recvd;
ktime_t bytes_start;
+ u64 num_losses;
};
/**
Index: dccp_tree_work03/net/dccp/ccids/lib/packet_history_sp.c
===================================================================
--- dccp_tree_work03.orig/net/dccp/ccids/lib/packet_history_sp.c 2009-10-08 22:58:21.418908270 -0300
+++ dccp_tree_work03/net/dccp/ccids/lib/packet_history_sp.c 2009-10-08 22:59:07.442411383 -0300
@@ -243,6 +243,7 @@
{
u64 s0 = tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno,
s1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_seqno,
+ n1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_ndp,
s2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_seqno,
s3 = DCCP_SKB_CB(skb)->dccpd_seq;
@@ -250,6 +251,7 @@
h->loss_count = 3;
tfrc_sp_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 3),
skb, n3);
+ h->num_losses = dccp_loss_count(s0, s1, n1);
return 1;
}
@@ -263,6 +265,7 @@
tfrc_sp_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 2),
skb, n3);
h->loss_count = 3;
+ h->num_losses = dccp_loss_count(s0, s1, n1);
return 1;
}
@@ -299,6 +302,7 @@
h->loss_start = tfrc_rx_hist_index(h, 3);
tfrc_sp_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 1), skb, n3);
h->loss_count = 3;
+ h->num_losses = dccp_loss_count(s0, s3, n3);
return 1;
}
Index: dccp_tree_work03/net/dccp/dccp.h
===================================================================
--- dccp_tree_work03.orig/net/dccp/dccp.h 2009-10-08 22:54:16.858907920 -0300
+++ dccp_tree_work03/net/dccp/dccp.h 2009-10-08 22:59:07.442411383 -0300
@@ -154,6 +154,22 @@
}
/**
+ * dccp_loss_count - Approximate the number of data packets lost in a row
+ * @s1: last known sequence number before the loss ('hole')
+ * @s2: first sequence number seen after the 'hole'
+ * @ndp: ndp count associated with packet having sequence number @s2
+ */
+static inline u64 dccp_loss_count(const u64 s1, const u64 s2, const u64 ndp)
+{
+ s64 delta = dccp_delta_seqno(s1, s2);
+
+ WARN_ON(delta < 0);
+ delta -= ndp + 1;
+
+ return delta > 0 ? delta : 0;
+}
+
+/**
* dccp_loss_free - Evaluates condition for data loss from RFC 4340, 7.7.1
* @s1: start sequence number
* @s2: end sequence number
@@ -162,10 +178,7 @@
*/
static inline bool dccp_loss_free(const u64 s1, const u64 s2, const u64 ndp)
{
- s64 delta = dccp_delta_seqno(s1, s2);
-
- WARN_ON(delta < 0);
- return (u64)delta <= ndp + 1;
+ return dccp_loss_count(s1, s2, ndp) == 0;
}
enum {
--
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