}
}
-void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h,
- const struct sk_buff *skb,
- const u32 ndp)
+static inline void tfrc_rx_hist_entry_from_skb(struct tfrc_rx_hist_entry *entry,
+ const struct sk_buff *skb,
+ const u32 ndp)
{
- struct tfrc_rx_hist_entry *entry = tfrc_rx_hist_last_rcv(h);
const struct dccp_hdr *dh = dccp_hdr(skb);
entry->tfrchrx_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
entry->tfrchrx_ndp = ndp;
entry->tfrchrx_tstamp = ktime_get_real();
}
+
+void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h,
+ const struct sk_buff *skb,
+ const u32 ndp)
+{
+ struct tfrc_rx_hist_entry *entry = tfrc_rx_hist_last_rcv(h);
+
+ tfrc_rx_hist_entry_from_skb(entry, skb, ndp);
+}
EXPORT_SYMBOL_GPL(tfrc_rx_hist_add_packet);
/* has the packet contained in skb been seen before? */
}
EXPORT_SYMBOL_GPL(tfrc_rx_hist_duplicate);
-/* initialise loss detection and disable RTT sampling */
-static inline void tfrc_rx_hist_loss_indicated(struct tfrc_rx_hist *h)
+static void tfrc_rx_hist_swap(struct tfrc_rx_hist *h, const u8 a, const u8 b)
+{
+ const u8 idx_a = tfrc_rx_hist_index(h, a),
+ idx_b = tfrc_rx_hist_index(h, b);
+ struct tfrc_rx_hist_entry *tmp = h->ring[idx_a];
+
+ h->ring[idx_a] = h->ring[idx_b];
+ h->ring[idx_b] = tmp;
+}
+
+/*
+ * Private helper functions for loss detection.
+ *
+ * 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.
+ */
+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 */
+ 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 (d21 == 1 || n1 >= d21) {
+ /* hole is filled: S0, S2, and S1 are consecutive */
+ h->loss_count = 0;
+ h->loss_start = tfrc_rx_hist_index(h, 1);
+ } else
+ /* 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 */
+ /*
+ * 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);
+ tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 1), skb, n2);
+ h->loss_count = 2;
+ }
+}
+
+/* return 1 if a new loss event has been identified */
+static int __two_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n3)
{
- h->loss_count = 1;
+ u64 s0 = tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno,
+ 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 */
+ 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) {
+ /*
+ * The sequence number order is S1, S3, S2
+ * Reorder history to insert entry 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);
+ h->loss_count = 3;
+ return 1;
+ }
+
+ /* S0 < S3 < S1 */
+ d31 = -d13;
+ d3 = dccp_delta_seqno(s0, s3);
+
+ if (d3 == 1 || n3 >= d3) { /* S3 is a successor of S0 */
+
+ if (d31 == 1 || n1 >= d31) {
+ /* hole between S0 and S1 filled by S3 */
+ int d2 = dccp_delta_seqno(s1, s2),
+ n2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_ndp;
+
+ if (d2 == 1 || n2 >= d2) {
+ /* entire hole filled by S0, S3, S1, S2 */
+ h->loss_start = tfrc_rx_hist_index(h, 2);
+ h->loss_count = 0;
+ } else {
+ /* gap remains between S1 and S2 */
+ h->loss_start = tfrc_rx_hist_index(h, 1);
+ h->loss_count = 1;
+ }
+
+ } else /* gap exists between S3 and S1, loss_count stays at 2 */
+ tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_loss_prev(h), skb, n3);
+
+ return 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
+ */
+ tfrc_rx_hist_swap(h, 0, 3);
+ h->loss_start = tfrc_rx_hist_index(h, 3);
+ tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 1), skb, n3);
+ h->loss_count = 3;
+
+ return 1;
}
-/* indicate whether previously a packet was detected missing */
-static inline int tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist *h)
+/* 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)
{
- return h->loss_count;
+ 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);
}
-/* any data packets missing between last reception and skb ? */
-int tfrc_rx_hist_new_loss_indicated(struct tfrc_rx_hist *h,
- const struct sk_buff *skb, u32 ndp)
+/* recycle RX history records to continue loss detection if necessary */
+static void __three_after_loss(struct tfrc_rx_hist *h)
{
- int delta = dccp_delta_seqno(tfrc_rx_hist_last_rcv(h)->tfrchrx_seqno,
- DCCP_SKB_CB(skb)->dccpd_seq);
+ /*
+ * 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.
+ */
+ 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,
+ n3 = tfrc_rx_hist_entry(h, 3)->tfrchrx_ndp;
+
+ if (d2 == 1 || n2 >= d2) { /* S2 is successor to S1 */
+
+ if (d3 == 1 || n3 >= d3) {
+ /* S3 is successor of S2: entire hole is filled */
+ h->loss_start = tfrc_rx_hist_index(h, 3);
+ h->loss_count = 0;
+ } else {
+ /* gap between S2 and S3 */
+ h->loss_start = tfrc_rx_hist_index(h, 2);
+ h->loss_count = 1;
+ }
+
+ } else { /* gap between S1 and S2 */
+ h->loss_start = tfrc_rx_hist_index(h, 1);
+ h->loss_count = 2;
+ }
+}
- if (delta > 1 && ndp < delta)
- tfrc_rx_hist_loss_indicated(h);
+/**
+ * tfrc_rx_handle_loss - Loss detection and further processing
+ * @h: The non-empty RX history object
+ * @lh: Loss Intervals database to update
+ * @skb: Currently received packet
+ * @ndp: The NDP count belonging to @skb
+ * @calc_first_li: Caller-dependent computation of first loss interval in @lh
+ * @sk: Used by @calc_first_li (see tfrc_lh_interval_add)
+ * 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.
+ */
+int tfrc_rx_handle_loss(struct tfrc_rx_hist *h,
+ struct tfrc_loss_hist *lh,
+ struct sk_buff *skb, u32 ndp,
+ u32 (*calc_first_li)(struct sock *), struct sock *sk)
+{
+ int is_new_loss = 0;
- return tfrc_rx_hist_loss_pending(h);
+ 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);
+ } else if (__two_after_loss(h, skb, ndp)) {
+ /*
+ * Update Loss Interval database and recycle RX records
+ */
+ is_new_loss = tfrc_lh_interval_add(lh, h, calc_first_li, sk);
+ __three_after_loss(h);
+ }
+ return is_new_loss;
}
-EXPORT_SYMBOL_GPL(tfrc_rx_hist_new_loss_indicated);
+EXPORT_SYMBOL_GPL(tfrc_rx_handle_loss);
int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h)
{
projects / linux-2.6-omap-h63xx.git / blobdiff