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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.c246
1 files changed, 199 insertions, 47 deletions
diff --git a/net/dccp/ccids/lib/loss_interval.c b/net/dccp/ccids/lib/loss_interval.c
index 372d7e75cdd8..174d3f13d93f 100644
--- a/net/dccp/ccids/lib/loss_interval.c
+++ b/net/dccp/ccids/lib/loss_interval.c
@@ -1,8 +1,8 @@
/*
* net/dccp/ccids/lib/loss_interval.c
*
- * Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
- * Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz>
+ * 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
@@ -15,58 +15,38 @@
#include <net/sock.h>
#include "../../dccp.h"
#include "loss_interval.h"
+#include "packet_history.h"
+#include "tfrc.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;
-}
+#define DCCP_LI_HIST_IVAL_F_LENGTH 8
-EXPORT_SYMBOL_GPL(dccp_li_hist_new);
+struct dccp_li_hist_entry {
+ struct list_head dccplih_node;
+ u64 dccplih_seqno:48,
+ dccplih_win_count:4;
+ u32 dccplih_interval;
+};
-void dccp_li_hist_delete(struct dccp_li_hist *hist)
-{
- const char* name = kmem_cache_name(hist->dccplih_slab);
+static struct kmem_cache *dccp_li_cachep __read_mostly;
- kmem_cache_destroy(hist->dccplih_slab);
- kfree(name);
- kfree(hist);
+static inline struct dccp_li_hist_entry *dccp_li_hist_entry_new(const gfp_t prio)
+{
+ return kmem_cache_alloc(dccp_li_cachep, prio);
}
-EXPORT_SYMBOL_GPL(dccp_li_hist_delete);
+static inline void dccp_li_hist_entry_delete(struct dccp_li_hist_entry *entry)
+{
+ if (entry != NULL)
+ kmem_cache_free(dccp_li_cachep, entry);
+}
-void dccp_li_hist_purge(struct dccp_li_hist *hist, struct list_head *list)
+void dccp_li_hist_purge(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);
+ kmem_cache_free(dccp_li_cachep, entry);
}
}
@@ -118,16 +98,16 @@ u32 dccp_li_hist_calc_i_mean(struct list_head *list)
EXPORT_SYMBOL_GPL(dccp_li_hist_calc_i_mean);
-int dccp_li_hist_interval_new(struct dccp_li_hist *hist,
- struct list_head *list, const u64 seq_loss, const u8 win_loss)
+static int dccp_li_hist_interval_new(struct list_head *list,
+ const u64 seq_loss, const u8 win_loss)
{
struct dccp_li_hist_entry *entry;
int i;
for (i = 0; i < DCCP_LI_HIST_IVAL_F_LENGTH; i++) {
- entry = dccp_li_hist_entry_new(hist, GFP_ATOMIC);
+ entry = dccp_li_hist_entry_new(GFP_ATOMIC);
if (entry == NULL) {
- dccp_li_hist_purge(hist, list);
+ dccp_li_hist_purge(list);
DCCP_BUG("loss interval list entry is NULL");
return 0;
}
@@ -140,4 +120,176 @@ int dccp_li_hist_interval_new(struct dccp_li_hist *hist,
return 1;
}
-EXPORT_SYMBOL_GPL(dccp_li_hist_interval_new);
+/* calculate first loss interval
+ *
+ * returns estimated loss interval in usecs */
+static u32 dccp_li_calc_first_li(struct sock *sk,
+ struct list_head *hist_list,
+ struct timeval *last_feedback,
+ u16 s, u32 bytes_recv,
+ u32 previous_x_recv)
+{
+ struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
+ u32 x_recv, p;
+ suseconds_t rtt, delta;
+ struct timeval tstamp = { 0, 0 };
+ int interval = 0;
+ int win_count = 0;
+ int step = 0;
+ u64 fval;
+
+ list_for_each_entry_safe(entry, next, hist_list, dccphrx_node) {
+ if (dccp_rx_hist_entry_data_packet(entry)) {
+ tail = entry;
+
+ switch (step) {
+ case 0:
+ tstamp = entry->dccphrx_tstamp;
+ win_count = entry->dccphrx_ccval;
+ step = 1;
+ break;
+ case 1:
+ interval = win_count - entry->dccphrx_ccval;
+ if (interval < 0)
+ interval += TFRC_WIN_COUNT_LIMIT;
+ if (interval > 4)
+ goto found;
+ break;
+ }
+ }
+ }
+
+ if (unlikely(step == 0)) {
+ DCCP_WARN("%s(%p), packet history has no data packets!\n",
+ dccp_role(sk), sk);
+ return ~0;
+ }
+
+ if (unlikely(interval == 0)) {
+ DCCP_WARN("%s(%p), Could not find a win_count interval > 0."
+ "Defaulting to 1\n", dccp_role(sk), sk);
+ interval = 1;
+ }
+found:
+ if (!tail) {
+ DCCP_CRIT("tail is null\n");
+ return ~0;
+ }
+
+ delta = timeval_delta(&tstamp, &tail->dccphrx_tstamp);
+ DCCP_BUG_ON(delta < 0);
+
+ rtt = delta * 4 / interval;
+ dccp_pr_debug("%s(%p), approximated RTT to %dus\n",
+ dccp_role(sk), sk, (int)rtt);
+
+ /*
+ * Determine the length of the first loss interval via inverse lookup.
+ * Assume that X_recv can be computed by the throughput equation
+ * s
+ * X_recv = --------
+ * R * fval
+ * Find some p such that f(p) = fval; return 1/p [RFC 3448, 6.3.1].
+ */
+ if (rtt == 0) { /* would result in divide-by-zero */
+ DCCP_WARN("RTT==0\n");
+ return ~0;
+ }
+
+ dccp_timestamp(sk, &tstamp);
+ delta = timeval_delta(&tstamp, last_feedback);
+ DCCP_BUG_ON(delta <= 0);
+
+ x_recv = scaled_div32(bytes_recv, delta);
+ if (x_recv == 0) { /* would also trigger divide-by-zero */
+ DCCP_WARN("X_recv==0\n");
+ if (previous_x_recv == 0) {
+ DCCP_BUG("stored value of X_recv is zero");
+ return ~0;
+ }
+ x_recv = previous_x_recv;
+ }
+
+ fval = scaled_div(s, rtt);
+ fval = scaled_div32(fval, x_recv);
+ p = tfrc_calc_x_reverse_lookup(fval);
+
+ dccp_pr_debug("%s(%p), receive rate=%u bytes/s, implied "
+ "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
+
+ if (p == 0)
+ return ~0;
+ else
+ return 1000000 / p;
+}
+
+void dccp_li_update_li(struct sock *sk,
+ struct list_head *li_hist_list,
+ struct list_head *hist_list,
+ struct timeval *last_feedback, u16 s, u32 bytes_recv,
+ u32 previous_x_recv, u64 seq_loss, u8 win_loss)
+{
+ struct dccp_li_hist_entry *head;
+ u64 seq_temp;
+
+ if (list_empty(li_hist_list)) {
+ if (!dccp_li_hist_interval_new(li_hist_list, seq_loss,
+ win_loss))
+ return;
+
+ head = list_entry(li_hist_list->next, struct dccp_li_hist_entry,
+ dccplih_node);
+ head->dccplih_interval = dccp_li_calc_first_li(sk, hist_list,
+ last_feedback,
+ s, bytes_recv,
+ previous_x_recv);
+ } else {
+ struct dccp_li_hist_entry *entry;
+ struct list_head *tail;
+
+ head = list_entry(li_hist_list->next, struct dccp_li_hist_entry,
+ dccplih_node);
+ /* FIXME win count check removed as was wrong */
+ /* should make this check with receive history */
+ /* and compare there as per section 10.2 of RFC4342 */
+
+ /* new loss event detected */
+ /* calculate last interval length */
+ seq_temp = dccp_delta_seqno(head->dccplih_seqno, seq_loss);
+ entry = dccp_li_hist_entry_new(GFP_ATOMIC);
+
+ if (entry == NULL) {
+ DCCP_BUG("out of memory - can not allocate entry");
+ return;
+ }
+
+ list_add(&entry->dccplih_node, li_hist_list);
+
+ tail = li_hist_list->prev;
+ list_del(tail);
+ kmem_cache_free(dccp_li_cachep, tail);
+
+ /* Create the newest interval */
+ entry->dccplih_seqno = seq_loss;
+ entry->dccplih_interval = seq_temp;
+ entry->dccplih_win_count = win_loss;
+ }
+}
+
+EXPORT_SYMBOL_GPL(dccp_li_update_li);
+
+static __init int dccp_li_init(void)
+{
+ dccp_li_cachep = kmem_cache_create("dccp_li_hist",
+ sizeof(struct dccp_li_hist_entry),
+ 0, SLAB_HWCACHE_ALIGN, NULL);
+ return dccp_li_cachep == NULL ? -ENOBUFS : 0;
+}
+
+static __exit void dccp_li_exit(void)
+{
+ kmem_cache_destroy(dccp_li_cachep);
+}
+
+module_init(dccp_li_init);
+module_exit(dccp_li_exit);
generated by cgit v1.2.3 (git 2.0.4) at 2024-05-23 22:44:54 +0000