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path: root/net/dccp/ccids/lib/loss_interval.c
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Diffstat (limited to 'net/dccp/ccids/lib/loss_interval.c')
-rw-r--r--net/dccp/ccids/lib/loss_interval.c247
1 files changed, 144 insertions, 103 deletions
diff --git a/net/dccp/ccids/lib/loss_interval.c b/net/dccp/ccids/lib/loss_interval.c
index 4c01a54143a..57f9fd78c4d 100644
--- a/net/dccp/ccids/lib/loss_interval.c
+++ b/net/dccp/ccids/lib/loss_interval.c
@@ -1,8 +1,7 @@
/*
- * net/dccp/ccids/lib/loss_interval.c
- *
- * Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
- * Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.nz>
+ * Copyright (c) 2007 The University of Aberdeen, Scotland, UK
+ * Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
+ * Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
*
* This program is free software; you can redistribute it and/or modify
@@ -10,135 +9,177 @@
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
+#include <net/sock.h>
+#include "tfrc.h"
-#include <linux/config.h>
-#include <linux/module.h>
-
-#include "loss_interval.h"
+static struct kmem_cache *tfrc_lh_slab __read_mostly;
+/* Loss Interval weights from [RFC 3448, 5.4], scaled by 10 */
+static const int tfrc_lh_weights[NINTERVAL] = { 10, 10, 10, 10, 8, 6, 4, 2 };
-struct dccp_li_hist *dccp_li_hist_new(const char *name)
+/* implements LIFO semantics on the array */
+static inline u8 LIH_INDEX(const u8 ctr)
{
- struct dccp_li_hist *hist = kmalloc(sizeof(*hist), GFP_ATOMIC);
- static const char dccp_li_hist_mask[] = "li_hist_%s";
- char *slab_name;
-
- if (hist == NULL)
- goto out;
-
- slab_name = kmalloc(strlen(name) + sizeof(dccp_li_hist_mask) - 1,
- GFP_ATOMIC);
- if (slab_name == NULL)
- goto out_free_hist;
-
- sprintf(slab_name, dccp_li_hist_mask, name);
- hist->dccplih_slab = kmem_cache_create(slab_name,
- sizeof(struct dccp_li_hist_entry),
- 0, SLAB_HWCACHE_ALIGN,
- NULL, NULL);
- if (hist->dccplih_slab == NULL)
- goto out_free_slab_name;
-out:
- return hist;
-out_free_slab_name:
- kfree(slab_name);
-out_free_hist:
- kfree(hist);
- hist = NULL;
- goto out;
+ return LIH_SIZE - 1 - (ctr % LIH_SIZE);
}
-EXPORT_SYMBOL_GPL(dccp_li_hist_new);
+/* the `counter' index always points at the next entry to be populated */
+static inline struct tfrc_loss_interval *tfrc_lh_peek(struct tfrc_loss_hist *lh)
+{
+ return lh->counter ? lh->ring[LIH_INDEX(lh->counter - 1)] : NULL;
+}
-void dccp_li_hist_delete(struct dccp_li_hist *hist)
+/* given i with 0 <= i <= k, return I_i as per the rfc3448bis notation */
+static inline u32 tfrc_lh_get_interval(struct tfrc_loss_hist *lh, const u8 i)
{
- const char* name = kmem_cache_name(hist->dccplih_slab);
+ BUG_ON(i >= lh->counter);
+ return lh->ring[LIH_INDEX(lh->counter - i - 1)]->li_length;
+}
- kmem_cache_destroy(hist->dccplih_slab);
- kfree(name);
- kfree(hist);
+/*
+ * On-demand allocation and de-allocation of entries
+ */
+static struct tfrc_loss_interval *tfrc_lh_demand_next(struct tfrc_loss_hist *lh)
+{
+ if (lh->ring[LIH_INDEX(lh->counter)] == NULL)
+ lh->ring[LIH_INDEX(lh->counter)] = kmem_cache_alloc(tfrc_lh_slab,
+ GFP_ATOMIC);
+ return lh->ring[LIH_INDEX(lh->counter)];
}
-EXPORT_SYMBOL_GPL(dccp_li_hist_delete);
+void tfrc_lh_cleanup(struct tfrc_loss_hist *lh)
+{
+ if (!tfrc_lh_is_initialised(lh))
+ return;
+
+ for (lh->counter = 0; lh->counter < LIH_SIZE; lh->counter++)
+ if (lh->ring[LIH_INDEX(lh->counter)] != NULL) {
+ kmem_cache_free(tfrc_lh_slab,
+ lh->ring[LIH_INDEX(lh->counter)]);
+ lh->ring[LIH_INDEX(lh->counter)] = NULL;
+ }
+}
-void dccp_li_hist_purge(struct dccp_li_hist *hist, struct list_head *list)
+static void tfrc_lh_calc_i_mean(struct tfrc_loss_hist *lh)
{
- struct dccp_li_hist_entry *entry, *next;
+ 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 */
+
+ if (k <= 0)
+ return;
+
+ for (i = 0; i <= k; i++) {
+ i_i = tfrc_lh_get_interval(lh, i);
- list_for_each_entry_safe(entry, next, list, dccplih_node) {
- list_del_init(&entry->dccplih_node);
- kmem_cache_free(hist->dccplih_slab, entry);
+ if (i < k) {
+ i_tot0 += i_i * tfrc_lh_weights[i];
+ w_tot += tfrc_lh_weights[i];
+ }
+ if (i > 0)
+ i_tot1 += i_i * tfrc_lh_weights[i-1];
}
-}
-EXPORT_SYMBOL_GPL(dccp_li_hist_purge);
+ lh->i_mean = max(i_tot0, i_tot1) / w_tot;
+}
-/* Weights used to calculate loss event rate */
-/*
- * These are integers as per section 8 of RFC3448. We can then divide by 4 *
- * when we use it.
+/**
+ * tfrc_lh_update_i_mean - Update the `open' loss interval I_0
+ * For recomputing p: returns `true' if p > p_prev <=> 1/p < 1/p_prev
*/
-static const int dccp_li_hist_w[DCCP_LI_HIST_IVAL_F_LENGTH] = {
- 4, 4, 4, 4, 3, 2, 1, 1,
-};
-
-u32 dccp_li_hist_calc_i_mean(struct list_head *list)
+u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb)
{
- struct dccp_li_hist_entry *li_entry, *li_next;
- int i = 0;
- u32 i_tot;
- u32 i_tot0 = 0;
- u32 i_tot1 = 0;
- u32 w_tot = 0;
-
- list_for_each_entry_safe(li_entry, li_next, list, dccplih_node) {
- if (i < DCCP_LI_HIST_IVAL_F_LENGTH) {
- i_tot0 += li_entry->dccplih_interval * dccp_li_hist_w[i];
- w_tot += dccp_li_hist_w[i];
- }
+ struct tfrc_loss_interval *cur = tfrc_lh_peek(lh);
+ u32 old_i_mean = lh->i_mean;
+ s64 len;
- if (i != 0)
- i_tot1 += li_entry->dccplih_interval * dccp_li_hist_w[i - 1];
+ if (cur == NULL) /* not initialised */
+ return 0;
- if (++i > DCCP_LI_HIST_IVAL_F_LENGTH)
- break;
- }
+ len = dccp_delta_seqno(cur->li_seqno, DCCP_SKB_CB(skb)->dccpd_seq) + 1;
- if (i != DCCP_LI_HIST_IVAL_F_LENGTH)
+ if (len - (s64)cur->li_length <= 0) /* duplicate or reordered */
return 0;
- i_tot = max(i_tot0, i_tot1);
+ if (SUB16(dccp_hdr(skb)->dccph_ccval, cur->li_ccval) > 4)
+ /*
+ * Implements RFC 4342, 10.2:
+ * If a packet S (skb) exists whose seqno comes `after' the one
+ * starting the current loss interval (cur) and if the modulo-16
+ * distance from C(cur) to C(S) is greater than 4, consider all
+ * subsequent packets as belonging to a new loss interval. This
+ * test is necessary since CCVal may wrap between intervals.
+ */
+ cur->li_is_closed = 1;
+
+ if (tfrc_lh_length(lh) == 1) /* due to RFC 3448, 6.3.1 */
+ return 0;
- /* FIXME: Why do we do this? -Ian McDonald */
- if (i_tot * 4 < w_tot)
- i_tot = w_tot * 4;
+ cur->li_length = len;
+ tfrc_lh_calc_i_mean(lh);
- return i_tot * 4 / w_tot;
+ return lh->i_mean < old_i_mean;
}
-EXPORT_SYMBOL_GPL(dccp_li_hist_calc_i_mean);
+/* Determine if `new_loss' does begin a new loss interval [RFC 4342, 10.2] */
+static inline u8 tfrc_lh_is_new_loss(struct tfrc_loss_interval *cur,
+ struct tfrc_rx_hist_entry *new_loss)
+{
+ return dccp_delta_seqno(cur->li_seqno, new_loss->tfrchrx_seqno) > 0 &&
+ (cur->li_is_closed || SUB16(new_loss->tfrchrx_ccval, cur->li_ccval) > 4);
+}
-struct dccp_li_hist_entry *dccp_li_hist_interval_new(struct dccp_li_hist *hist,
- struct list_head *list,
- const u64 seq_loss,
- const u8 win_loss)
+/**
+ * tfrc_lh_interval_add - Insert new record into the Loss Interval database
+ * @lh: Loss Interval database
+ * @rh: Receive history containing a fresh loss event
+ * @calc_first_li: Caller-dependent routine to compute length of first interval
+ * @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,
+ u32 (*calc_first_li)(struct sock *), struct sock *sk)
{
- struct dccp_li_hist_entry *tail = NULL, *entry;
- int i;
-
- for (i = 0; i <= DCCP_LI_HIST_IVAL_F_LENGTH; ++i) {
- entry = dccp_li_hist_entry_new(hist, SLAB_ATOMIC);
- if (entry == NULL) {
- dccp_li_hist_purge(hist, list);
- return NULL;
- }
- if (tail == NULL)
- tail = entry;
- list_add(&entry->dccplih_node, list);
+ 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;
+
+ new = tfrc_lh_demand_next(lh);
+ if (unlikely(new == NULL)) {
+ DCCP_CRIT("Cannot allocate/add loss record.");
+ return 0;
+ }
+
+ new->li_seqno = tfrc_rx_hist_loss_prev(rh)->tfrchrx_seqno;
+ new->li_ccval = tfrc_rx_hist_loss_prev(rh)->tfrchrx_ccval;
+ new->li_is_closed = 0;
+
+ if (++lh->counter == 1)
+ lh->i_mean = new->li_length = (*calc_first_li)(sk);
+ else {
+ cur->li_length = dccp_delta_seqno(cur->li_seqno, new->li_seqno);
+ new->li_length = dccp_delta_seqno(new->li_seqno,
+ tfrc_rx_hist_last_rcv(rh)->tfrchrx_seqno) + 1;
+ if (lh->counter > (2*LIH_SIZE))
+ lh->counter -= LIH_SIZE;
+
+ tfrc_lh_calc_i_mean(lh);
}
+ return 1;
+}
- entry->dccplih_seqno = seq_loss;
- entry->dccplih_win_count = win_loss;
- return tail;
+int __init tfrc_li_init(void)
+{
+ tfrc_lh_slab = kmem_cache_create("tfrc_li_hist",
+ sizeof(struct tfrc_loss_interval), 0,
+ SLAB_HWCACHE_ALIGN, NULL);
+ return tfrc_lh_slab == NULL ? -ENOBUFS : 0;
}
-EXPORT_SYMBOL_GPL(dccp_li_hist_interval_new);
+void tfrc_li_exit(void)
+{
+ if (tfrc_lh_slab != NULL) {
+ kmem_cache_destroy(tfrc_lh_slab);
+ tfrc_lh_slab = NULL;
+ }
+}
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