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-rw-r--r--net/dccp/ccids/ccid3.c110
-rw-r--r--net/dccp/ccids/ccid3.h21
-rw-r--r--net/dccp/ccids/lib/packet_history.c39
-rw-r--r--net/dccp/ccids/lib/packet_history.h22
4 files changed, 73 insertions, 119 deletions
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 278e170..ce80591 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -91,19 +91,16 @@ static inline u64 rfc3390_initial_rate(struct sock *sk)
return scaled_div(w_init << 6, hc->tx_rtt);
}
-/*
- * Recalculate t_ipi and delta (should be called whenever X changes)
+/**
+ * ccid3_update_send_interval - Calculate new t_ipi = s / X_inst
+ * This respects the granularity of X_inst (64 * bytes/second).
*/
static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hc)
{
- /* Calculate new t_ipi = s / X_inst (X_inst is in 64 * bytes/second) */
hc->tx_t_ipi = scaled_div32(((u64)hc->tx_s) << 6, hc->tx_x);
- /* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
- hc->tx_delta = min_t(u32, hc->tx_t_ipi / 2, TFRC_OPSYS_HALF_TIME_GRAN);
-
- ccid3_pr_debug("t_ipi=%u, delta=%u, s=%u, X=%u\n", hc->tx_t_ipi,
- hc->tx_delta, hc->tx_s, (unsigned)(hc->tx_x >> 6));
+ ccid3_pr_debug("t_ipi=%u, s=%u, X=%u\n", hc->tx_t_ipi,
+ hc->tx_s, (unsigned)(hc->tx_x >> 6));
}
static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hc, ktime_t now)
@@ -332,15 +329,15 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
delay = ktime_us_delta(hc->tx_t_nom, now);
ccid3_pr_debug("delay=%ld\n", (long)delay);
/*
- * Scheduling of packet transmissions [RFC 3448, 4.6]
+ * Scheduling of packet transmissions (RFC 5348, 8.3)
*
* if (t_now > t_nom - delta)
* // send the packet now
* else
* // send the packet in (t_nom - t_now) milliseconds.
*/
- if (delay - (s64)hc->tx_delta >= 1000)
- return (u32)delay / 1000L;
+ if (delay >= TFRC_T_DELTA)
+ return (u32)delay / USEC_PER_MSEC;
ccid3_hc_tx_update_win_count(hc, now);
break;
@@ -373,6 +370,7 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
{
struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
struct ccid3_options_received *opt_recv = &hc->tx_options_received;
+ struct tfrc_tx_hist_entry *acked;
ktime_t now;
unsigned long t_nfb;
u32 pinv, r_sample;
@@ -386,17 +384,24 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
hc->tx_state != TFRC_SSTATE_NO_FBACK)
return;
- now = ktime_get_real();
-
- /* Estimate RTT from history if ACK number is valid */
- r_sample = tfrc_tx_hist_rtt(hc->tx_hist,
- DCCP_SKB_CB(skb)->dccpd_ack_seq, now);
- if (r_sample == 0) {
- DCCP_WARN("%s(%p): %s with bogus ACK-%llu\n", dccp_role(sk), sk,
- dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type),
- (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq);
+ /*
+ * Locate the acknowledged packet in the TX history.
+ *
+ * Returning "entry not found" here can for instance happen when
+ * - the host has not sent out anything (e.g. a passive server),
+ * - the Ack is outdated (packet with higher Ack number was received),
+ * - it is a bogus Ack (for a packet not sent on this connection).
+ */
+ acked = tfrc_tx_hist_find_entry(hc->tx_hist, dccp_hdr_ack_seq(skb));
+ if (acked == NULL)
return;
- }
+ /* For the sake of RTT sampling, ignore/remove all older entries */
+ tfrc_tx_hist_purge(&acked->next);
+
+ /* Update the moving average for the RTT estimate (RFC 3448, 4.3) */
+ now = ktime_get_real();
+ r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp));
+ hc->tx_rtt = tfrc_ewma(hc->tx_rtt, r_sample, 9);
/* Update receive rate in units of 64 * bytes/second */
hc->tx_x_recv = opt_recv->ccid3or_receive_rate;
@@ -408,11 +413,7 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
hc->tx_p = 0;
else /* can not exceed 100% */
hc->tx_p = scaled_div(1, pinv);
- /*
- * Validate new RTT sample and update moving average
- */
- r_sample = dccp_sample_rtt(sk, r_sample);
- hc->tx_rtt = tfrc_ewma(hc->tx_rtt, r_sample, 9);
+
/*
* Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3
*/
@@ -484,60 +485,31 @@ static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
unsigned char len, u16 idx,
unsigned char *value)
{
- int rc = 0;
- const struct dccp_sock *dp = dccp_sk(sk);
struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
struct ccid3_options_received *opt_recv = &hc->tx_options_received;
__be32 opt_val;
- if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
- opt_recv->ccid3or_seqno = dp->dccps_gsr;
- opt_recv->ccid3or_loss_event_rate = ~0;
- opt_recv->ccid3or_loss_intervals_idx = 0;
- opt_recv->ccid3or_loss_intervals_len = 0;
- opt_recv->ccid3or_receive_rate = 0;
- }
-
switch (option) {
+ case TFRC_OPT_RECEIVE_RATE:
case TFRC_OPT_LOSS_EVENT_RATE:
if (unlikely(len != 4)) {
- DCCP_WARN("%s(%p), invalid len %d "
- "for TFRC_OPT_LOSS_EVENT_RATE\n",
- dccp_role(sk), sk, len);
- rc = -EINVAL;
- } else {
- opt_val = get_unaligned((__be32 *)value);
- opt_recv->ccid3or_loss_event_rate = ntohl(opt_val);
- ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
- dccp_role(sk), sk,
- opt_recv->ccid3or_loss_event_rate);
+ DCCP_WARN("%s(%p), invalid len %d for %u\n",
+ dccp_role(sk), sk, len, option);
+ return -EINVAL;
}
- break;
- case TFRC_OPT_LOSS_INTERVALS:
- opt_recv->ccid3or_loss_intervals_idx = idx;
- opt_recv->ccid3or_loss_intervals_len = len;
- ccid3_pr_debug("%s(%p), LOSS_INTERVALS=(%u, %u)\n",
- dccp_role(sk), sk,
- opt_recv->ccid3or_loss_intervals_idx,
- opt_recv->ccid3or_loss_intervals_len);
- break;
- case TFRC_OPT_RECEIVE_RATE:
- if (unlikely(len != 4)) {
- DCCP_WARN("%s(%p), invalid len %d "
- "for TFRC_OPT_RECEIVE_RATE\n",
- dccp_role(sk), sk, len);
- rc = -EINVAL;
- } else {
- opt_val = get_unaligned((__be32 *)value);
- opt_recv->ccid3or_receive_rate = ntohl(opt_val);
+ opt_val = ntohl(get_unaligned((__be32 *)value));
+
+ if (option == TFRC_OPT_RECEIVE_RATE) {
+ opt_recv->ccid3or_receive_rate = opt_val;
ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
- dccp_role(sk), sk,
- opt_recv->ccid3or_receive_rate);
+ dccp_role(sk), sk, opt_val);
+ } else {
+ opt_recv->ccid3or_loss_event_rate = opt_val;
+ ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
+ dccp_role(sk), sk, opt_val);
}
- break;
}
-
- return rc;
+ return 0;
}
static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
diff --git a/net/dccp/ccids/ccid3.h b/net/dccp/ccids/ccid3.h
index b7e569c..9eb90b8 100644
--- a/net/dccp/ccids/ccid3.h
+++ b/net/dccp/ccids/ccid3.h
@@ -45,12 +45,22 @@
/* Two seconds as per RFC 5348, 4.2 */
#define TFRC_INITIAL_TIMEOUT (2 * USEC_PER_SEC)
-/* In usecs - half the scheduling granularity as per RFC3448 4.6 */
-#define TFRC_OPSYS_HALF_TIME_GRAN (USEC_PER_SEC / (2 * HZ))
-
/* Parameter t_mbi from [RFC 3448, 4.3]: backoff interval in seconds */
#define TFRC_T_MBI 64
+/*
+ * The t_delta parameter (RFC 5348, 8.3): delays of less than %USEC_PER_MSEC are
+ * rounded down to 0, since sk_reset_timer() here uses millisecond granularity.
+ * Hence we can use a constant t_delta = %USEC_PER_MSEC when HZ >= 500. A coarse
+ * resolution of HZ < 500 means that the error is below one timer tick (t_gran)
+ * when using the constant t_delta = t_gran / 2 = %USEC_PER_SEC / (2 * HZ).
+ */
+#if (HZ >= 500)
+# define TFRC_T_DELTA USEC_PER_MSEC
+#else
+# define TFRC_T_DELTA (USEC_PER_SEC / (2 * HZ))
+#endif
+
enum ccid3_options {
TFRC_OPT_LOSS_EVENT_RATE = 192,
TFRC_OPT_LOSS_INTERVALS = 193,
@@ -58,9 +68,6 @@ enum ccid3_options {
};
struct ccid3_options_received {
- u64 ccid3or_seqno:48,
- ccid3or_loss_intervals_idx:16;
- u16 ccid3or_loss_intervals_len;
u32 ccid3or_loss_event_rate;
u32 ccid3or_receive_rate;
};
@@ -90,7 +97,6 @@ enum ccid3_hc_tx_states {
* @tx_no_feedback_timer: Handle to no feedback timer
* @tx_t_ld: Time last doubled during slow start
* @tx_t_nom: Nominal send time of next packet
- * @tx_delta: Send timer delta (RFC 3448, 4.6) in usecs
* @tx_hist: Packet history
* @tx_options_received: Parsed set of retrieved options
*/
@@ -109,7 +115,6 @@ struct ccid3_hc_tx_sock {
struct timer_list tx_no_feedback_timer;
ktime_t tx_t_ld;
ktime_t tx_t_nom;
- u32 tx_delta;
struct tfrc_tx_hist_entry *tx_hist;
struct ccid3_options_received tx_options_received;
};
diff --git a/net/dccp/ccids/lib/packet_history.c b/net/dccp/ccids/lib/packet_history.c
index 3a4f414..de8fe29 100644
--- a/net/dccp/ccids/lib/packet_history.c
+++ b/net/dccp/ccids/lib/packet_history.c
@@ -38,18 +38,6 @@
#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
*/
@@ -71,15 +59,6 @@ void tfrc_tx_packet_history_exit(void)
}
}
-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());
@@ -107,24 +86,6 @@ void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp)
*headp = NULL;
}
-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;
-}
-
-
/*
* Receiver History Routines
*/
diff --git a/net/dccp/ccids/lib/packet_history.h b/net/dccp/ccids/lib/packet_history.h
index 7df6c52..7ee4a9d 100644
--- a/net/dccp/ccids/lib/packet_history.h
+++ b/net/dccp/ccids/lib/packet_history.h
@@ -40,12 +40,28 @@
#include <linux/slab.h>
#include "tfrc.h"
-struct tfrc_tx_hist_entry;
+/**
+ * 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;
+};
+
+static inline 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;
+}
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);
/* Subtraction a-b modulo-16, respects circular wrap-around */
#define SUB16(a, b) (((a) + 16 - (b)) & 0xF)
generated by cgit v1.1 at 2024-12-24 17:03:12 +0000