[TFRC]: Hide tx history details from the CCIDs

Based on a previous patch by Gerrit Renker.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 41 insertions, 28 deletions

diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index f73542ab9d08..49338370eb04 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -399,7 +399,6 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
 {
         struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
         struct ccid3_options_received *opt_recv;
-        struct tfrc_tx_hist_entry *packet;
         ktime_t now;
         unsigned long t_nfb;
         u32 pinv, r_sample;
@@ -414,19 +413,17 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
         switch (hctx->ccid3hctx_state) {
         case TFRC_SSTATE_NO_FBACK:
         case TFRC_SSTATE_FBACK:
+                now = ktime_get_real();
+
                 /* estimate RTT from history if ACK number is valid */
-                packet = tfrc_tx_hist_find_entry(hctx->ccid3hctx_hist,
-                                                 DCCP_SKB_CB(skb)->dccpd_ack_seq);
-                if (packet == NULL) {
+                r_sample = tfrc_tx_hist_rtt(hctx->ccid3hctx_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);
                         return;
                 }
-                /*
-                 * Garbage-collect older (irrelevant) entries
-                 */
-                tfrc_tx_hist_purge(&packet->next);
 
                 /* Update receive rate in units of 64 * bytes/second */
                 hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate;
@@ -438,12 +435,10 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
                         hctx->ccid3hctx_p = 0;
                 else                                   /* can not exceed 100% */
                         hctx->ccid3hctx_p = 1000000 / pinv;
-
-                now = ktime_get_real();
                 /*
-                 * Calculate new RTT sample and update moving average
+                 * Validate new RTT sample and update moving average
                  */
-                r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, packet->stamp));
+                r_sample = dccp_sample_rtt(sk, r_sample);
                 hctx->ccid3hctx_rtt = tfrc_ewma(hctx->ccid3hctx_rtt, r_sample, 9);
 
                 if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
diff --git a/net/dccp/ccids/lib/packet_history.c b/net/dccp/ccids/lib/packet_history.c
index 139736064713..4805de996568 100644
--- a/net/dccp/ccids/lib/packet_history.c
+++ b/net/dccp/ccids/lib/packet_history.c
@@ -39,12 +39,24 @@
 #include <linux/string.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;
+};
+
 /*
  * Transmitter History Routines
  */
 static struct kmem_cache *tfrc_tx_hist;
 
-struct tfrc_tx_hist_entry *
+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)
@@ -52,7 +64,6 @@ struct tfrc_tx_hist_entry *
 
         return head;
 }
-EXPORT_SYMBOL_GPL(tfrc_tx_hist_find_entry);
 
 int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno)
 {
@@ -83,6 +94,24 @@ void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp)
 }
 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
  */
diff --git a/net/dccp/ccids/lib/packet_history.h b/net/dccp/ccids/lib/packet_history.h
index 5c07182dd659..0670f46dd53c 100644
--- a/net/dccp/ccids/lib/packet_history.h
+++ b/net/dccp/ccids/lib/packet_history.h
@@ -48,23 +48,12 @@
 #define TFRC_WIN_COUNT_PER_RTT   4
 #define TFRC_WIN_COUNT_LIMIT    16
 
-/**
- *  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;
-};
+struct tfrc_tx_hist_entry;
 
 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 struct tfrc_tx_hist_entry *
-        tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 ackno);
+extern u32  tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head,
+                             const u64 seqno, const ktime_t now);
 
 /*
  *      Receiver History data structures and declarations