[DCCP] ccid3: Set NoFeedback Timeout according to RFC 3448

This corrects the setting of the nofeedback timer with regard to RFC
3448 - previously it was not set to max(4*R, 2*s/X) as specified. Using
the maximum of 1 second as upper bound (as it was done before) can have
detrimental effects, especially if R is small.

Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

1 files changed, 10 insertions, 12 deletions

diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index f0ed67c84a55..577fd0ef84e5 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -163,7 +163,7 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
 {
         struct sock *sk = (struct sock *)data;
         struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
-        unsigned long next_tmout = USEC_PER_SEC / 5;
+        unsigned long t_nfb = USEC_PER_SEC / 5;
 
         bh_lock_sock(sk);
         if (sock_owned_by_user(sk)) {
@@ -191,7 +191,7 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
                                hctx->ccid3hctx_x);
                 /* The value of R is still undefined and so we can not recompute
                  * the timout value. Keep initial value as per [RFC 4342, 5]. */
-                next_tmout = TFRC_INITIAL_TIMEOUT;
+                t_nfb = TFRC_INITIAL_TIMEOUT;
                 ccid3_update_send_time(hctx);
                 break;
         case TFRC_SSTATE_FBACK:
@@ -228,10 +228,9 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
                 }
                 /*
                  * Schedule no feedback timer to expire in
-                 * max(4 * t_RTO, 2 * s/X)  =  max(4 * t_RTO, 2 * t_ipi)
-                 * XXX This is non-standard, RFC 3448, 4.3 uses 4 * R
+                 * max(4 * R, 2 * s/X)  =  max(4 * R, 2 * t_ipi)
                  */
-                next_tmout = max(hctx->ccid3hctx_t_rto, 2*hctx->ccid3hctx_t_ipi);
+                t_nfb = max(4 * hctx->ccid3hctx_rtt, 2 * hctx->ccid3hctx_t_ipi);
                 break;
         case TFRC_SSTATE_NO_SENT:
                 DCCP_BUG("Illegal %s state NO_SENT, sk=%p", dccp_role(sk), sk);
@@ -244,7 +243,7 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
 
 restart_timer:
         sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
-                           jiffies + usecs_to_jiffies(next_tmout));
+                           jiffies + usecs_to_jiffies(t_nfb));
 out:
         bh_unlock_sock(sk);
         sock_put(sk);
@@ -396,7 +395,7 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
         struct ccid3_options_received *opt_recv;
         struct dccp_tx_hist_entry *packet;
         struct timeval now;
-        unsigned long next_tmout; 
+        unsigned long t_nfb;
         u32 t_elapsed;
         u32 pinv;
         u32 x_recv;
@@ -498,18 +497,17 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
                                                    USEC_PER_SEC            );
                 /*
                  * Schedule no feedback timer to expire in
-                 * max(4 * t_RTO, 2 * s/X)  =  max(4 * t_RTO, 2 * t_ipi)
-                 * XXX This is non-standard, RFC 3448, 4.3 uses 4 * R
+                 * max(4 * R, 2 * s/X)  =  max(4 * R, 2 * t_ipi)
                  */
-                next_tmout = max(hctx->ccid3hctx_t_rto, 2*hctx->ccid3hctx_t_ipi);
+                t_nfb = max(4 * hctx->ccid3hctx_rtt, 2 * hctx->ccid3hctx_t_ipi);
                         
                 ccid3_pr_debug("%s, sk=%p, Scheduled no feedback timer to "
                                "expire in %lu jiffies (%luus)\n",
                                dccp_role(sk), sk,
-                               usecs_to_jiffies(next_tmout), next_tmout); 
+                               usecs_to_jiffies(t_nfb), t_nfb);
 
                 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer, 
-                                   jiffies + usecs_to_jiffies(next_tmout));
+                                   jiffies + usecs_to_jiffies(t_nfb));
 
                 /* set idle flag */
                 hctx->ccid3hctx_idle = 1;