*/
#include <linux/string.h>
+#include <linux/slab.h>
#include "packet_history.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;
-};
+#include "../../dccp.h"
/*
* Transmitter History Routines
*/
static struct kmem_cache *tfrc_tx_hist_slab;
-static struct tfrc_tx_hist_entry *
- tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno)
+int __init tfrc_tx_packet_history_init(void)
{
- while (head != NULL && head->seqno != seqno)
- head = head->next;
+ tfrc_tx_hist_slab = kmem_cache_create("tfrc_tx_hist",
+ sizeof(struct tfrc_tx_hist_entry),
+ 0, SLAB_HWCACHE_ALIGN, NULL);
+ return tfrc_tx_hist_slab == NULL ? -ENOBUFS : 0;
+}
- return head;
+void tfrc_tx_packet_history_exit(void)
+{
+ if (tfrc_tx_hist_slab != NULL) {
+ kmem_cache_destroy(tfrc_tx_hist_slab);
+ tfrc_tx_hist_slab = NULL;
+ }
}
int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno)
}
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 struct kmem_cache *tfrc_rx_hist_slab;
-struct dccp_rx_hist_entry *dccp_rx_hist_entry_new(const u32 ndp,
- const struct sk_buff *skb,
- const gfp_t prio)
+int __init tfrc_rx_packet_history_init(void)
{
- struct dccp_rx_hist_entry *entry = kmem_cache_alloc(tfrc_rx_hist_slab,
- prio);
-
- if (entry != NULL) {
- const struct dccp_hdr *dh = dccp_hdr(skb);
+ tfrc_rx_hist_slab = kmem_cache_create("tfrc_rxh_cache",
+ sizeof(struct tfrc_rx_hist_entry),
+ 0, SLAB_HWCACHE_ALIGN, NULL);
+ return tfrc_rx_hist_slab == NULL ? -ENOBUFS : 0;
+}
- 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;
- entry->dccphrx_tstamp = ktime_get_real();
+void tfrc_rx_packet_history_exit(void)
+{
+ if (tfrc_rx_hist_slab != NULL) {
+ kmem_cache_destroy(tfrc_rx_hist_slab);
+ tfrc_rx_hist_slab = NULL;
}
+}
- return entry;
+static inline void tfrc_rx_hist_entry_from_skb(struct tfrc_rx_hist_entry *entry,
+ const struct sk_buff *skb,
+ const u64 ndp)
+{
+ const struct dccp_hdr *dh = dccp_hdr(skb);
+
+ entry->tfrchrx_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
+ entry->tfrchrx_ccval = dh->dccph_ccval;
+ entry->tfrchrx_type = dh->dccph_type;
+ entry->tfrchrx_ndp = ndp;
+ entry->tfrchrx_tstamp = ktime_get_real();
}
-EXPORT_SYMBOL_GPL(dccp_rx_hist_entry_new);
-static inline void dccp_rx_hist_entry_delete(struct dccp_rx_hist_entry *entry)
+void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h,
+ const struct sk_buff *skb,
+ const u64 ndp)
{
- kmem_cache_free(tfrc_rx_hist_slab, entry);
+ 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);
-int dccp_rx_hist_find_entry(const struct list_head *list, const u64 seq,
- u8 *ccval)
+/* has the packet contained in skb been seen before? */
+int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb)
{
- struct dccp_rx_hist_entry *packet = NULL, *entry;
+ const u64 seq = DCCP_SKB_CB(skb)->dccpd_seq;
+ int i;
- list_for_each_entry(entry, list, dccphrx_node)
- if (entry->dccphrx_seqno == seq) {
- packet = entry;
- break;
- }
+ if (dccp_delta_seqno(tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno, seq) <= 0)
+ return 1;
- if (packet)
- *ccval = packet->dccphrx_ccval;
+ for (i = 1; i <= h->loss_count; i++)
+ if (tfrc_rx_hist_entry(h, i)->tfrchrx_seqno == seq)
+ return 1;
- return packet != NULL;
+ return 0;
}
+EXPORT_SYMBOL_GPL(tfrc_rx_hist_duplicate);
-EXPORT_SYMBOL_GPL(dccp_rx_hist_find_entry);
-struct dccp_rx_hist_entry *
- dccp_rx_hist_find_data_packet(const struct list_head *list)
+static void tfrc_rx_hist_swap(struct tfrc_rx_hist *h, const u8 a, const u8 b)
{
- struct dccp_rx_hist_entry *entry, *packet = NULL;
+ 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];
- list_for_each_entry(entry, list, dccphrx_node)
- if (entry->dccphrx_type == DCCP_PKT_DATA ||
- entry->dccphrx_type == DCCP_PKT_DATAACK) {
- packet = entry;
- break;
- }
-
- return packet;
+ h->ring[idx_a] = h->ring[idx_b];
+ h->ring[idx_b] = tmp;
}
-EXPORT_SYMBOL_GPL(dccp_rx_hist_find_data_packet);
+/*
+ * 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 __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);
+ }
+}
-void dccp_rx_hist_add_packet(struct list_head *rx_list,
- struct list_head *li_list,
- struct dccp_rx_hist_entry *packet,
- u64 nonloss_seqno)
+static void __one_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n2)
{
- struct dccp_rx_hist_entry *entry, *next;
- u8 num_later = 0;
-
- list_add(&packet->dccphrx_node, rx_list);
-
- num_later = TFRC_RECV_NUM_LATE_LOSS + 1;
-
- if (!list_empty(li_list)) {
- list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
- if (num_later == 0) {
- if (after48(nonloss_seqno,
- entry->dccphrx_seqno)) {
- list_del_init(&entry->dccphrx_node);
- dccp_rx_hist_entry_delete(entry);
- }
- } else if (dccp_rx_hist_entry_data_packet(entry))
- --num_later;
- }
- } else {
- int step = 0;
- u8 win_count = 0; /* Not needed, but lets shut up gcc */
- int tmp;
+ 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;
+
+ 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 */
+
+ if (dccp_loss_free(s0, s2, n2)) {
+ u64 n1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_ndp;
+
+ 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);
+ } 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 { /* gap between S0 and S2 */
/*
- * We have no loss interval history so we need at least one
- * rtt:s of data packets to approximate rtt.
+ * Reorder history to insert S2 between S0 and S1
*/
- list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
- if (num_later == 0) {
- switch (step) {
- case 0:
- step = 1;
- /* OK, find next data packet */
- num_later = 1;
- break;
- case 1:
- step = 2;
- /* OK, find next data packet */
- num_later = 1;
- win_count = entry->dccphrx_ccval;
- break;
- case 2:
- tmp = win_count - entry->dccphrx_ccval;
- if (tmp < 0)
- tmp += TFRC_WIN_COUNT_LIMIT;
- if (tmp > TFRC_WIN_COUNT_PER_RTT + 1) {
- /*
- * We have found a packet older
- * than one rtt remove the rest
- */
- step = 3;
- } else /* OK, find next data packet */
- num_later = 1;
- break;
- case 3:
- list_del_init(&entry->dccphrx_node);
- dccp_rx_hist_entry_delete(entry);
- break;
- }
- } else if (dccp_rx_hist_entry_data_packet(entry))
- --num_later;
- }
+ 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;
}
}
-EXPORT_SYMBOL_GPL(dccp_rx_hist_add_packet);
+/* 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)
+{
+ 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;
+
+ 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 */
-void dccp_rx_hist_purge(struct list_head *list)
+ if (dccp_delta_seqno(s1, s3) > 0) { /* S1 < S3 < 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);
+ h->loss_count = 3;
+ return 1;
+ }
+
+ /* S0 < S3 < S1 */
+
+ if (dccp_loss_free(s0, s3, n3)) {
+ u64 n1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_ndp;
+
+ if (dccp_loss_free(s3, s1, n1)) {
+ /* hole between S0 and S1 filled by S3 */
+ u64 n2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_ndp;
+
+ 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;
+ } 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: 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);
+ tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 1), skb, n3);
+ h->loss_count = 3;
+
+ return 1;
+}
+
+/* recycle RX history records to continue loss detection if necessary */
+static void __three_after_loss(struct tfrc_rx_hist *h)
{
- struct dccp_rx_hist_entry *entry, *next;
+ /*
+ * 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.
+ */
+ 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 (dccp_loss_free(s1, s2, n2)) {
+
+ 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 {
+ /* gap between S2 and S3 */
+ h->loss_start = tfrc_rx_hist_index(h, 2);
+ h->loss_count = 1;
+ }
- list_for_each_entry_safe(entry, next, list, dccphrx_node) {
- list_del_init(&entry->dccphrx_node);
- dccp_rx_hist_entry_delete(entry);
+ } else { /* gap between S1 and S2 */
+ h->loss_start = tfrc_rx_hist_index(h, 1);
+ h->loss_count = 2;
}
}
-EXPORT_SYMBOL_GPL(dccp_rx_hist_purge);
+/**
+ * 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.
+ * 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, const u64 ndp,
+ u32 (*calc_first_li)(struct sock *), struct sock *sk)
+{
+ int is_new_loss = 0;
+
+ 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);
+ } 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_handle_loss);
-__init int packet_history_init(void)
+int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h)
{
- tfrc_tx_hist_slab = kmem_cache_create("tfrc_tx_hist",
- sizeof(struct tfrc_tx_hist_entry), 0,
- SLAB_HWCACHE_ALIGN, NULL);
- if (tfrc_tx_hist_slab == NULL)
- goto out_err;
+ int i;
- tfrc_rx_hist_slab = kmem_cache_create("tfrc_rx_hist",
- sizeof(struct dccp_rx_hist_entry), 0,
- SLAB_HWCACHE_ALIGN, NULL);
- if (tfrc_rx_hist_slab == NULL)
- goto out_free_tx;
+ for (i = 0; i <= TFRC_NDUPACK; i++) {
+ h->ring[i] = kmem_cache_alloc(tfrc_rx_hist_slab, GFP_ATOMIC);
+ if (h->ring[i] == NULL)
+ goto out_free;
+ }
+ h->loss_count = h->loss_start = 0;
return 0;
-out_free_tx:
- kmem_cache_destroy(tfrc_tx_hist_slab);
- tfrc_tx_hist_slab = NULL;
-out_err:
+out_free:
+ while (i-- != 0) {
+ kmem_cache_free(tfrc_rx_hist_slab, h->ring[i]);
+ h->ring[i] = NULL;
+ }
return -ENOBUFS;
}
+EXPORT_SYMBOL_GPL(tfrc_rx_hist_alloc);
-void packet_history_exit(void)
+void tfrc_rx_hist_purge(struct tfrc_rx_hist *h)
{
- if (tfrc_tx_hist_slab != NULL) {
- kmem_cache_destroy(tfrc_tx_hist_slab);
- tfrc_tx_hist_slab = NULL;
+ int i;
+
+ for (i = 0; i <= TFRC_NDUPACK; ++i)
+ if (h->ring[i] != NULL) {
+ kmem_cache_free(tfrc_rx_hist_slab, h->ring[i]);
+ h->ring[i] = NULL;
+ }
+}
+EXPORT_SYMBOL_GPL(tfrc_rx_hist_purge);
+
+/**
+ * tfrc_rx_hist_rtt_last_s - reference entry to compute RTT samples against
+ */
+static inline struct tfrc_rx_hist_entry *
+ tfrc_rx_hist_rtt_last_s(const struct tfrc_rx_hist *h)
+{
+ return h->ring[0];
+}
+
+/**
+ * tfrc_rx_hist_rtt_prev_s: previously suitable (wrt rtt_last_s) RTT-sampling entry
+ */
+static inline struct tfrc_rx_hist_entry *
+ tfrc_rx_hist_rtt_prev_s(const struct tfrc_rx_hist *h)
+{
+ return h->ring[h->rtt_sample_prev];
+}
+
+/**
+ * tfrc_rx_hist_sample_rtt - Sample RTT from timestamp / CCVal
+ * Based on ideas presented in RFC 4342, 8.1. Returns 0 if it was not able
+ * to compute a sample with given data - calling function should check this.
+ */
+u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, const struct sk_buff *skb)
+{
+ u32 sample = 0,
+ delta_v = SUB16(dccp_hdr(skb)->dccph_ccval,
+ tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval);
+
+ if (delta_v < 1 || delta_v > 4) { /* unsuitable CCVal delta */
+ if (h->rtt_sample_prev == 2) { /* previous candidate stored */
+ sample = SUB16(tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_ccval,
+ tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval);
+ if (sample)
+ sample = 4 / sample *
+ ktime_us_delta(tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_tstamp,
+ tfrc_rx_hist_rtt_last_s(h)->tfrchrx_tstamp);
+ else /*
+ * FIXME: This condition is in principle not
+ * possible but occurs when CCID is used for
+ * two-way data traffic. I have tried to trace
+ * it, but the cause does not seem to be here.
+ */
+ DCCP_BUG("please report to dccp@vger.kernel.org"
+ " => prev = %u, last = %u",
+ tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_ccval,
+ tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval);
+ } else if (delta_v < 1) {
+ h->rtt_sample_prev = 1;
+ goto keep_ref_for_next_time;
+ }
+
+ } else if (delta_v == 4) /* optimal match */
+ sample = ktime_to_us(net_timedelta(tfrc_rx_hist_rtt_last_s(h)->tfrchrx_tstamp));
+ else { /* suboptimal match */
+ h->rtt_sample_prev = 2;
+ goto keep_ref_for_next_time;
}
- if (tfrc_rx_hist_slab != NULL) {
- kmem_cache_destroy(tfrc_rx_hist_slab);
- tfrc_rx_hist_slab = NULL;
+ if (unlikely(sample > DCCP_SANE_RTT_MAX)) {
+ DCCP_WARN("RTT sample %u too large, using max\n", sample);
+ sample = DCCP_SANE_RTT_MAX;
}
+
+ h->rtt_sample_prev = 0; /* use current entry as next reference */
+keep_ref_for_next_time:
+
+ return sample;
}
+EXPORT_SYMBOL_GPL(tfrc_rx_hist_sample_rtt);
git.openpandora.org / pandora-kernel.git / blobdiff