[CCID3]: Move the loss interval code to loss_interval.[ch]

And put this into net/dccp/ccids/lib/, where packet_history.[ch] will also be
moved and then we'll have a tfrc_lib.ko module that will be used by
dccp_ccid3.ko and other CCIDs that are variations of TFRC (RFC 3448).

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 144 insertions, 0 deletions

diff --git a/net/dccp/ccids/lib/loss_interval.c b/net/dccp/ccids/lib/loss_interval.c
new file mode 100644
index 000000000000..4c01a54143ad
--- /dev/null
+++ b/net/dccp/ccids/lib/loss_interval.c
@@ -0,0 +1,144 @@
+/*
+ *  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) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+
+#include "loss_interval.h"
+
+struct dccp_li_hist *dccp_li_hist_new(const char *name)
+{
+	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;
+}
+
+EXPORT_SYMBOL_GPL(dccp_li_hist_new);
+
+void dccp_li_hist_delete(struct dccp_li_hist *hist)
+{
+	const char* name = kmem_cache_name(hist->dccplih_slab);
+
+	kmem_cache_destroy(hist->dccplih_slab);
+	kfree(name);
+	kfree(hist);
+}
+
+EXPORT_SYMBOL_GPL(dccp_li_hist_delete);
+
+void dccp_li_hist_purge(struct dccp_li_hist *hist, struct list_head *list)
+{
+	struct dccp_li_hist_entry *entry, *next;
+
+	list_for_each_entry_safe(entry, next, list, dccplih_node) {
+		list_del_init(&entry->dccplih_node);
+		kmem_cache_free(hist->dccplih_slab, entry);
+	}
+}
+
+EXPORT_SYMBOL_GPL(dccp_li_hist_purge);
+
+/* 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.
+ */
+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)
+{
+	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];
+		}
+
+		if (i != 0)
+			i_tot1 += li_entry->dccplih_interval * dccp_li_hist_w[i - 1];
+
+		if (++i > DCCP_LI_HIST_IVAL_F_LENGTH)
+			break;
+	}
+
+	if (i != DCCP_LI_HIST_IVAL_F_LENGTH)
+		return 0;
+
+	i_tot = max(i_tot0, i_tot1);
+
+	/* FIXME: Why do we do this? -Ian McDonald */
+	if (i_tot * 4 < w_tot)
+		i_tot = w_tot * 4;
+
+	return i_tot * 4 / w_tot;
+}
+
+EXPORT_SYMBOL_GPL(dccp_li_hist_calc_i_mean);
+
+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)
+{
+	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);
+	}
+
+	entry->dccplih_seqno     = seq_loss;
+	entry->dccplih_win_count = win_loss;
+	return tail;
+}
+
+EXPORT_SYMBOL_GPL(dccp_li_hist_interval_new);