#include "packet_history.h"
#include "../../dccp.h"
-/**
- * tfrc_tx_hist_entry - Simple singly-linked TX history list
- * @next: next oldest entry (LIFO order)
- * @seqno: sequence number of this entry
- * @stamp: send time of packet with sequence number @seqno
- */
-struct tfrc_tx_hist_entry {
- struct tfrc_tx_hist_entry *next;
- u64 seqno;
- ktime_t stamp;
-};
-
/*
* Transmitter History Routines
*/
}
}
-static struct tfrc_tx_hist_entry *
- tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno)
-{
- while (head != NULL && head->seqno != seqno)
- head = head->next;
-
- return head;
-}
-
int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno)
{
struct tfrc_tx_hist_entry *entry = kmem_cache_alloc(tfrc_tx_hist_slab, gfp_any());
}
EXPORT_SYMBOL_GPL(tfrc_tx_hist_purge);
-u32 tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head, const u64 seqno,
- const ktime_t now)
-{
- u32 rtt = 0;
- struct tfrc_tx_hist_entry *packet = tfrc_tx_hist_find_entry(head, seqno);
-
- if (packet != NULL) {
- rtt = ktime_us_delta(now, packet->stamp);
- /*
- * Garbage-collect older (irrelevant) entries:
- */
- tfrc_tx_hist_purge(&packet->next);
- }
-
- return rtt;
-}
-EXPORT_SYMBOL_GPL(tfrc_tx_hist_rtt);
-
-
/*
* Receiver History Routines
*/
static inline void tfrc_rx_hist_entry_from_skb(struct tfrc_rx_hist_entry *entry,
const struct sk_buff *skb,
- const u32 ndp)
+ const u64 ndp)
{
const struct dccp_hdr *dh = dccp_hdr(skb);
void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h,
const struct sk_buff *skb,
- const u32 ndp)
+ const u64 ndp)
{
struct tfrc_rx_hist_entry *entry = tfrc_rx_hist_last_rcv(h);
*
* In the descriptions, `Si' refers to the sequence number of entry number i,
* whose NDP count is `Ni' (lower case is used for variables).
- * Note: All __after_loss functions expect that a test against duplicates has
- * been performed already: the seqno of the skb must not be less than the
- * seqno of loss_prev; and it must not equal that of any valid hist_entry.
+ * Note: All __xxx_loss functions expect that a test against duplicates has been
+ * performed already: the seqno of the skb must not be less than the seqno
+ * of loss_prev; and it must not equal that of any valid history entry.
*/
+static void __do_track_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u64 n1)
+{
+ u64 s0 = tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno,
+ s1 = DCCP_SKB_CB(skb)->dccpd_seq;
+
+ if (!dccp_loss_free(s0, s1, n1)) { /* gap between S0 and S1 */
+ h->loss_count = 1;
+ tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 1), skb, n1);
+ }
+}
+
static void __one_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n2)
{
u64 s0 = tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno,
s1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_seqno,
s2 = DCCP_SKB_CB(skb)->dccpd_seq;
- int n1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_ndp,
- d12 = dccp_delta_seqno(s1, s2), d2;
- if (d12 > 0) { /* S1 < S2 */
+ if (likely(dccp_delta_seqno(s1, s2) > 0)) { /* S1 < S2 */
h->loss_count = 2;
tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 2), skb, n2);
return;
}
/* S0 < S2 < S1 */
- d2 = dccp_delta_seqno(s0, s2);
- if (d2 == 1 || n2 >= d2) { /* S2 is direct successor of S0 */
- int d21 = -d12;
+ if (dccp_loss_free(s0, s2, n2)) {
+ u64 n1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_ndp;
- if (d21 == 1 || n1 >= d21) {
+ if (dccp_loss_free(s2, s1, n1)) {
/* hole is filled: S0, S2, and S1 are consecutive */
h->loss_count = 0;
h->loss_start = tfrc_rx_hist_index(h, 1);
/* gap between S2 and S1: just update loss_prev */
tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_loss_prev(h), skb, n2);
- } else { /* hole between S0 and S2 */
+ } else { /* gap between S0 and S2 */
/*
- * Reorder history to insert S2 between S0 and s1
+ * Reorder history to insert S2 between S0 and S1
*/
tfrc_rx_hist_swap(h, 0, 3);
h->loss_start = tfrc_rx_hist_index(h, 3);
s1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_seqno,
s2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_seqno,
s3 = DCCP_SKB_CB(skb)->dccpd_seq;
- int n1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_ndp,
- d23 = dccp_delta_seqno(s2, s3), d13, d3, d31;
- if (d23 > 0) { /* S2 < S3 */
+ if (likely(dccp_delta_seqno(s2, s3) > 0)) { /* S2 < S3 */
h->loss_count = 3;
tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 3), skb, n3);
return 1;
}
/* S3 < S2 */
- d13 = dccp_delta_seqno(s1, s3);
- if (d13 > 0) {
+ if (dccp_delta_seqno(s1, s3) > 0) { /* S1 < S3 < S2 */
/*
- * The sequence number order is S1, S3, S2
- * Reorder history to insert entry between S1 and S2
+ * Reorder history to insert S3 between S1 and S2
*/
tfrc_rx_hist_swap(h, 2, 3);
tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 2), skb, n3);
}
/* S0 < S3 < S1 */
- d31 = -d13;
- d3 = dccp_delta_seqno(s0, s3);
- if (d3 == 1 || n3 >= d3) { /* S3 is a successor of S0 */
+ if (dccp_loss_free(s0, s3, n3)) {
+ u64 n1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_ndp;
- if (d31 == 1 || n1 >= d31) {
+ if (dccp_loss_free(s3, s1, n1)) {
/* hole between S0 and S1 filled by S3 */
- int d2 = dccp_delta_seqno(s1, s2),
- n2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_ndp;
+ u64 n2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_ndp;
- if (d2 == 1 || n2 >= d2) {
+ if (dccp_loss_free(s1, s2, n2)) {
/* entire hole filled by S0, S3, S1, S2 */
h->loss_start = tfrc_rx_hist_index(h, 2);
h->loss_count = 0;
}
/*
- * The remaining case: S3 is not a successor of S0.
- * Sequence order is S0, S3, S1, S2; reorder to insert between S0 and S1
+ * The remaining case: S0 < S3 < S1 < S2; gap between S0 and S3
+ * Reorder history to insert S3 between S0 and S1.
*/
tfrc_rx_hist_swap(h, 0, 3);
h->loss_start = tfrc_rx_hist_index(h, 3);
return 1;
}
-/* return the signed modulo-2^48 sequence number distance from entry e1 to e2 */
-static s64 tfrc_rx_hist_delta_seqno(struct tfrc_rx_hist *h, u8 e1, u8 e2)
-{
- DCCP_BUG_ON(e1 > h->loss_count || e2 > h->loss_count);
-
- return dccp_delta_seqno(tfrc_rx_hist_entry(h, e1)->tfrchrx_seqno,
- tfrc_rx_hist_entry(h, e2)->tfrchrx_seqno);
-}
-
/* recycle RX history records to continue loss detection if necessary */
static void __three_after_loss(struct tfrc_rx_hist *h)
{
/*
- * The distance between S0 and S1 is always greater than 1 and the NDP
- * count of S1 is smaller than this distance. Otherwise there would
- * have been no loss. Hence it is only necessary to see whether there
- * are further missing data packets between S1/S2 and S2/S3.
+ * At this stage we know already that there is a gap between S0 and S1
+ * (since S0 was the highest sequence number received before detecting
+ * the loss). To recycle the loss record, it is thus only necessary to
+ * check for other possible gaps between S1/S2 and between S2/S3.
*/
- int d2 = tfrc_rx_hist_delta_seqno(h, 1, 2),
- d3 = tfrc_rx_hist_delta_seqno(h, 2, 3),
- n2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_ndp,
+ u64 s1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_seqno,
+ s2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_seqno,
+ s3 = tfrc_rx_hist_entry(h, 3)->tfrchrx_seqno;
+ u64 n2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_ndp,
n3 = tfrc_rx_hist_entry(h, 3)->tfrchrx_ndp;
- if (d2 == 1 || n2 >= d2) { /* S2 is successor to S1 */
+ if (dccp_loss_free(s1, s2, n2)) {
- if (d3 == 1 || n3 >= d3) {
- /* S3 is successor of S2: entire hole is filled */
+ if (dccp_loss_free(s2, s3, n3)) {
+ /* no gap between S2 and S3: entire hole is filled */
h->loss_start = tfrc_rx_hist_index(h, 3);
h->loss_count = 0;
} else {
h->loss_count = 1;
}
- } else { /* gap between S1 and S2 */
+ } else { /* gap between S1 and S2 */
h->loss_start = tfrc_rx_hist_index(h, 1);
h->loss_count = 2;
}
* Chooses action according to pending loss, updates LI database when a new
* loss was detected, and does required post-processing. Returns 1 when caller
* should send feedback, 0 otherwise.
+ * Since it also takes care of reordering during loss detection and updates the
+ * records accordingly, the caller should not perform any more RX history
+ * operations when loss_count is greater than 0 after calling this function.
*/
int tfrc_rx_handle_loss(struct tfrc_rx_hist *h,
struct tfrc_loss_hist *lh,
- struct sk_buff *skb, u32 ndp,
+ struct sk_buff *skb, const u64 ndp,
u32 (*calc_first_li)(struct sock *), struct sock *sk)
{
int is_new_loss = 0;
- if (h->loss_count == 1) {
+ if (h->loss_count == 0) {
+ __do_track_loss(h, skb, ndp);
+ } else if (h->loss_count == 1) {
__one_after_loss(h, skb, ndp);
} else if (h->loss_count != 2) {
DCCP_BUG("invalid loss_count %d", h->loss_count);
git.openpandora.org / pandora-kernel.git / blobdiff