dccp ccid-3: Update the RX history records in one place
This patch is a requirement for enabling ECN support later on. With that change
in mind, the following preparations are done:
* renamed handle_loss() into congestion_event() since it returns true when a
congestion event happens (it will eventually also take care of ECN packets);
* lets tfrc_rx_congestion_event() always update the RX history records, since
this routine needs to be called for each non-duplicate packet anyway;
* made all involved boolean-type functions to have return type `bool';
Updating the RX history records is now only necessary for the packets received
up to sending the first feedback. The receiver code becomes again simpler.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index f2f9514..aca072b 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -657,41 +657,26 @@
static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
{
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
- enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE;
const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp;
const bool is_data_packet = dccp_data_packet(skb);
/*
* Perform loss detection and handle pending losses
*/
- if (tfrc_rx_handle_loss(&hcrx->hist, &hcrx->li_hist,
- skb, ndp, ccid3_first_li, sk)) {
- do_feedback = CCID3_FBACK_PARAM_CHANGE;
- goto done_receiving;
- }
-
- if (unlikely(hcrx->feedback == CCID3_FBACK_NONE)) {
- if (is_data_packet)
- do_feedback = CCID3_FBACK_INITIAL;
- goto update_records;
- }
-
- if (tfrc_rx_hist_loss_pending(&hcrx->hist))
- return; /* done receiving */
-
+ if (tfrc_rx_congestion_event(&hcrx->hist, &hcrx->li_hist,
+ skb, ndp, ccid3_first_li, sk))
+ ccid3_hc_rx_send_feedback(sk, skb, CCID3_FBACK_PARAM_CHANGE);
+ /*
+ * Feedback for first non-empty data packet (RFC 3448, 6.3)
+ */
+ else if (unlikely(hcrx->feedback == CCID3_FBACK_NONE && is_data_packet))
+ ccid3_hc_rx_send_feedback(sk, skb, CCID3_FBACK_INITIAL);
/*
* Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3
*/
- if (is_data_packet &&
- SUB16(dccp_hdr(skb)->dccph_ccval, hcrx->last_counter) > 3)
- do_feedback = CCID3_FBACK_PERIODIC;
-
-update_records:
- tfrc_rx_hist_add_packet(&hcrx->hist, skb, ndp);
-
-done_receiving:
- if (do_feedback)
- ccid3_hc_rx_send_feedback(sk, skb, do_feedback);
+ else if (!tfrc_rx_hist_loss_pending(&hcrx->hist) && is_data_packet &&
+ SUB16(dccp_hdr(skb)->dccph_ccval, hcrx->last_counter) > 3)
+ ccid3_hc_rx_send_feedback(sk, skb, CCID3_FBACK_PERIODIC);
}
static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
diff --git a/net/dccp/ccids/lib/loss_interval.c b/net/dccp/ccids/lib/loss_interval.c
index fe5c2a3..b1ae8f8 100644
--- a/net/dccp/ccids/lib/loss_interval.c
+++ b/net/dccp/ccids/lib/loss_interval.c
@@ -140,18 +140,18 @@
* @sk: Used by @calc_first_li in caller-specific way (subtyping)
* Updates I_mean and returns 1 if a new interval has in fact been added to @lh.
*/
-int tfrc_lh_interval_add(struct tfrc_loss_hist *lh, struct tfrc_rx_hist *rh,
- u32 (*calc_first_li)(struct sock *), struct sock *sk)
+bool tfrc_lh_interval_add(struct tfrc_loss_hist *lh, struct tfrc_rx_hist *rh,
+ u32 (*calc_first_li)(struct sock *), struct sock *sk)
{
struct tfrc_loss_interval *cur = tfrc_lh_peek(lh), *new;
if (cur != NULL && !tfrc_lh_is_new_loss(cur, tfrc_rx_hist_loss_prev(rh)))
- return 0;
+ return false;
new = tfrc_lh_demand_next(lh);
if (unlikely(new == NULL)) {
DCCP_CRIT("Cannot allocate/add loss record.");
- return 0;
+ return false;
}
new->li_seqno = tfrc_rx_hist_loss_prev(rh)->tfrchrx_seqno;
@@ -169,7 +169,7 @@
tfrc_lh_calc_i_mean(lh);
}
- return 1;
+ return true;
}
EXPORT_SYMBOL_GPL(tfrc_lh_interval_add);
diff --git a/net/dccp/ccids/lib/loss_interval.h b/net/dccp/ccids/lib/loss_interval.h
index f101ae2..d08a226 100644
--- a/net/dccp/ccids/lib/loss_interval.h
+++ b/net/dccp/ccids/lib/loss_interval.h
@@ -67,7 +67,7 @@
struct tfrc_rx_hist;
-extern int tfrc_lh_interval_add(struct tfrc_loss_hist *, struct tfrc_rx_hist *,
+extern bool tfrc_lh_interval_add(struct tfrc_loss_hist *, struct tfrc_rx_hist *,
u32 (*first_li)(struct sock *), struct sock *);
extern void tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *);
extern void tfrc_lh_cleanup(struct tfrc_loss_hist *lh);
diff --git a/net/dccp/ccids/lib/packet_history.c b/net/dccp/ccids/lib/packet_history.c
index 547ad09..cce9f03 100644
--- a/net/dccp/ccids/lib/packet_history.c
+++ b/net/dccp/ccids/lib/packet_history.c
@@ -192,10 +192,8 @@
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 */
+ 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)
@@ -328,13 +326,13 @@
}
/**
- * 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)
+ * tfrc_rx_congestion_event - 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
+ * @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.
@@ -342,12 +340,12 @@
* 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)
+bool tfrc_rx_congestion_event(struct tfrc_rx_hist *h,
+ struct tfrc_loss_hist *lh,
+ struct sk_buff *skb, const u64 ndp,
+ u32 (*first_li)(struct sock *), struct sock *sk)
{
- int is_new_loss = 0;
+ bool new_event = false;
if (tfrc_rx_hist_duplicate(h, skb))
return 0;
@@ -355,6 +353,7 @@
if (h->loss_count == 0) {
__do_track_loss(h, skb, ndp);
tfrc_rx_hist_sample_rtt(h, skb);
+ tfrc_rx_hist_add_packet(h, skb, ndp);
} else if (h->loss_count == 1) {
__one_after_loss(h, skb, ndp);
} else if (h->loss_count != 2) {
@@ -363,7 +362,7 @@
/*
* Update Loss Interval database and recycle RX records
*/
- is_new_loss = tfrc_lh_interval_add(lh, h, calc_first_li, sk);
+ new_event = tfrc_lh_interval_add(lh, h, first_li, sk);
__three_after_loss(h);
}
@@ -378,12 +377,12 @@
}
/* RFC 3448, 6.1: update I_0, whose growth implies p <= p_prev */
- if (!is_new_loss)
+ if (!new_event)
tfrc_lh_update_i_mean(lh, skb);
- return is_new_loss;
+ return new_event;
}
-EXPORT_SYMBOL_GPL(tfrc_rx_handle_loss);
+EXPORT_SYMBOL_GPL(tfrc_rx_congestion_event);
/* Compute the sending rate X_recv measured between feedback intervals */
u32 tfrc_rx_hist_x_recv(struct tfrc_rx_hist *h, const u32 last_x_recv)
diff --git a/net/dccp/ccids/lib/packet_history.h b/net/dccp/ccids/lib/packet_history.h
index 6552be6..555e65c 100644
--- a/net/dccp/ccids/lib/packet_history.h
+++ b/net/dccp/ccids/lib/packet_history.h
@@ -186,11 +186,11 @@
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, const u64 ndp,
- u32 (*first_li)(struct sock *sk),
- struct sock *sk);
+extern bool tfrc_rx_congestion_event(struct tfrc_rx_hist *h,
+ struct tfrc_loss_hist *lh,
+ struct sk_buff *skb, const u64 ndp,
+ u32 (*first_li)(struct sock *sk),
+ struct sock *sk);
extern void tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h,
const struct sk_buff *skb);
extern int tfrc_rx_hist_init(struct tfrc_rx_hist *h, struct sock *sk);