[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);