/*
- * net/dccp/packet_history.h
+ * Packet RX/TX history data structures and routines for TFRC-based protocols.
*
+ * Copyright (c) 2007 The University of Aberdeen, Scotland, UK
* Copyright (c) 2005-6 The University of Waikato, Hamilton, New Zealand.
*
- * An implementation of the DCCP protocol
- *
* This code has been developed by the University of Waikato WAND
* research group. For further information please see http://www.wand.net.nz/
* or e-mail Ian McDonald - ian.mcdonald@jandi.co.nz
#include <linux/list.h>
#include <linux/slab.h>
-#include <linux/time.h>
+#include "tfrc.h"
-#include "../../dccp.h"
+struct tfrc_tx_hist_entry;
-/* Number of later packets received before one is considered lost */
-#define TFRC_RECV_NUM_LATE_LOSS 3
+extern int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno);
+extern void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp);
+extern u32 tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head,
+ const u64 seqno, const ktime_t now);
-#define TFRC_WIN_COUNT_PER_RTT 4
-#define TFRC_WIN_COUNT_LIMIT 16
+/* Subtraction a-b modulo-16, respects circular wrap-around */
+#define SUB16(a, b) (((a) + 16 - (b)) & 0xF)
-/*
- * Transmitter History data structures and declarations
+/* Number of packets to wait after a missing packet (RFC 4342, 6.1) */
+#define TFRC_NDUPACK 3
+
+/**
+ * tfrc_rx_hist_entry - Store information about a single received packet
+ * @tfrchrx_seqno: DCCP packet sequence number
+ * @tfrchrx_ccval: window counter value of packet (RFC 4342, 8.1)
+ * @tfrchrx_ndp: the NDP count (if any) of the packet
+ * @tfrchrx_tstamp: actual receive time of packet
*/
-struct dccp_tx_hist_entry {
- struct list_head dccphtx_node;
- u64 dccphtx_seqno:48,
- dccphtx_sent:1;
- u32 dccphtx_rtt;
- struct timeval dccphtx_tstamp;
+struct tfrc_rx_hist_entry {
+ u64 tfrchrx_seqno:48,
+ tfrchrx_ccval:4,
+ tfrchrx_type:4;
+ u32 tfrchrx_ndp; /* In fact it is from 8 to 24 bits */
+ ktime_t tfrchrx_tstamp;
};
-struct dccp_tx_hist {
- struct kmem_cache *dccptxh_slab;
+/**
+ * tfrc_rx_hist - RX history structure for TFRC-based protocols
+ *
+ * @ring: Packet history for RTT sampling and loss detection
+ * @loss_count: Number of entries in circular history
+ * @loss_start: Movable index (for loss detection)
+ * @rtt_sample_prev: Used during RTT sampling, points to candidate entry
+ */
+struct tfrc_rx_hist {
+ struct tfrc_rx_hist_entry *ring[TFRC_NDUPACK + 1];
+ u8 loss_count:2,
+ loss_start:2;
+#define rtt_sample_prev loss_start
};
-extern struct dccp_tx_hist *dccp_tx_hist_new(const char *name);
-extern void dccp_tx_hist_delete(struct dccp_tx_hist *hist);
-
-static inline struct dccp_tx_hist_entry *
- dccp_tx_hist_entry_new(struct dccp_tx_hist *hist,
- const gfp_t prio)
+/**
+ * tfrc_rx_hist_index - index to reach n-th entry after loss_start
+ */
+static inline u8 tfrc_rx_hist_index(const struct tfrc_rx_hist *h, const u8 n)
{
- struct dccp_tx_hist_entry *entry = kmem_cache_alloc(hist->dccptxh_slab,
- prio);
-
- if (entry != NULL)
- entry->dccphtx_sent = 0;
-
- return entry;
+ return (h->loss_start + n) & TFRC_NDUPACK;
}
-static inline struct dccp_tx_hist_entry *
- dccp_tx_hist_head(struct list_head *list)
+/**
+ * tfrc_rx_hist_last_rcv - entry with highest-received-seqno so far
+ */
+static inline struct tfrc_rx_hist_entry *
+ tfrc_rx_hist_last_rcv(const struct tfrc_rx_hist *h)
{
- struct dccp_tx_hist_entry *head = NULL;
-
- if (!list_empty(list))
- head = list_entry(list->next, struct dccp_tx_hist_entry,
- dccphtx_node);
- return head;
+ return h->ring[tfrc_rx_hist_index(h, h->loss_count)];
}
-extern struct dccp_tx_hist_entry *
- dccp_tx_hist_find_entry(const struct list_head *list,
- const u64 seq);
-
-static inline void dccp_tx_hist_add_entry(struct list_head *list,
- struct dccp_tx_hist_entry *entry)
+/**
+ * tfrc_rx_hist_entry - return the n-th history entry after loss_start
+ */
+static inline struct tfrc_rx_hist_entry *
+ tfrc_rx_hist_entry(const struct tfrc_rx_hist *h, const u8 n)
{
- list_add(&entry->dccphtx_node, list);
+ return h->ring[tfrc_rx_hist_index(h, n)];
}
-static inline void dccp_tx_hist_entry_delete(struct dccp_tx_hist *hist,
- struct dccp_tx_hist_entry *entry)
+/**
+ * tfrc_rx_hist_loss_prev - entry with highest-received-seqno before loss was detected
+ */
+static inline struct tfrc_rx_hist_entry *
+ tfrc_rx_hist_loss_prev(const struct tfrc_rx_hist *h)
{
- if (entry != NULL)
- kmem_cache_free(hist->dccptxh_slab, entry);
+ return h->ring[h->loss_start];
}
-extern void dccp_tx_hist_purge(struct dccp_tx_hist *hist,
- struct list_head *list);
-
-extern void dccp_tx_hist_purge_older(struct dccp_tx_hist *hist,
- struct list_head *list,
- struct dccp_tx_hist_entry *next);
-
-/*
- * Receiver History data structures and declarations
- */
-struct dccp_rx_hist_entry {
- struct list_head dccphrx_node;
- u64 dccphrx_seqno:48,
- dccphrx_ccval:4,
- dccphrx_type:4;
- u32 dccphrx_ndp; /* In fact it is from 8 to 24 bits */
- struct timeval dccphrx_tstamp;
-};
-
-struct dccp_rx_hist {
- struct kmem_cache *dccprxh_slab;
-};
-
-extern struct dccp_rx_hist *dccp_rx_hist_new(const char *name);
-extern void dccp_rx_hist_delete(struct dccp_rx_hist *hist);
-
-static inline struct dccp_rx_hist_entry *
- dccp_rx_hist_entry_new(struct dccp_rx_hist *hist,
- const struct sock *sk,
- const u32 ndp,
- const struct sk_buff *skb,
- const gfp_t prio)
+/* initialise loss detection and disable RTT sampling */
+static inline void tfrc_rx_hist_loss_indicated(struct tfrc_rx_hist *h)
{
- struct dccp_rx_hist_entry *entry = kmem_cache_alloc(hist->dccprxh_slab,
- prio);
-
- if (entry != NULL) {
- const struct dccp_hdr *dh = dccp_hdr(skb);
-
- entry->dccphrx_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
- entry->dccphrx_ccval = dh->dccph_ccval;
- entry->dccphrx_type = dh->dccph_type;
- entry->dccphrx_ndp = ndp;
- dccp_timestamp(sk, &entry->dccphrx_tstamp);
- }
-
- return entry;
+ h->loss_count = 1;
}
-static inline struct dccp_rx_hist_entry *
- dccp_rx_hist_head(struct list_head *list)
+/* indicate whether previously a packet was detected missing */
+static inline int tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist *h)
{
- struct dccp_rx_hist_entry *head = NULL;
-
- if (!list_empty(list))
- head = list_entry(list->next, struct dccp_rx_hist_entry,
- dccphrx_node);
- return head;
+ return h->loss_count;
}
-extern int dccp_rx_hist_find_entry(const struct list_head *list, const u64 seq,
- u8 *ccval);
-extern struct dccp_rx_hist_entry *
- dccp_rx_hist_find_data_packet(const struct list_head *list);
-
-extern void dccp_rx_hist_add_packet(struct dccp_rx_hist *hist,
- struct list_head *rx_list,
- struct list_head *li_list,
- struct dccp_rx_hist_entry *packet,
- u64 nonloss_seqno);
-
-static inline void dccp_rx_hist_entry_delete(struct dccp_rx_hist *hist,
- struct dccp_rx_hist_entry *entry)
+/* any data packets missing between last reception and skb ? */
+static inline int tfrc_rx_hist_new_loss_indicated(struct tfrc_rx_hist *h,
+ const struct sk_buff *skb,
+ u32 ndp)
{
- if (entry != NULL)
- kmem_cache_free(hist->dccprxh_slab, entry);
-}
+ int delta = dccp_delta_seqno(tfrc_rx_hist_last_rcv(h)->tfrchrx_seqno,
+ DCCP_SKB_CB(skb)->dccpd_seq);
-extern void dccp_rx_hist_purge(struct dccp_rx_hist *hist,
- struct list_head *list);
+ if (delta > 1 && ndp < delta)
+ tfrc_rx_hist_loss_indicated(h);
-static inline int
- dccp_rx_hist_entry_data_packet(const struct dccp_rx_hist_entry *entry)
-{
- return entry->dccphrx_type == DCCP_PKT_DATA ||
- entry->dccphrx_type == DCCP_PKT_DATAACK;
+ return tfrc_rx_hist_loss_pending(h);
}
-extern u64 dccp_rx_hist_detect_loss(struct list_head *rx_list,
- struct list_head *li_list, u8 *win_loss);
+extern void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h,
+ const struct sk_buff *skb, const u32 ndp);
+
+extern int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb);
+
+struct tfrc_loss_hist;
+extern int tfrc_rx_handle_loss(struct tfrc_rx_hist *h,
+ struct tfrc_loss_hist *lh,
+ struct sk_buff *skb, u32 ndp,
+ u32 (*first_li)(struct sock *sk),
+ struct sock *sk);
+extern u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h,
+ const struct sk_buff *skb);
+extern int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h);
+extern void tfrc_rx_hist_purge(struct tfrc_rx_hist *h);
#endif /* _DCCP_PKT_HIST_ */
projects / linux-2.6-omap-h63xx.git / blobdiff