From 2e2e9e92bd723244ea20fa488b1780111f2b05e1 Mon Sep 17 00:00:00 2001
From: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Date: Mon, 13 Nov 2006 13:23:52 -0200
Subject: [DCCP]: Add sysctls to control retransmission behaviour

This adds 3 sysctls which govern the retransmission behaviour of DCCP control
packets (3way handshake, feature negotiation).

It removes 4 FIXMEs from the code.

The close resemblance of sysctl variables to their TCP analogues is emphasised
not only by their name, but also by giving them the same initial values.
This is useful since there is not much practical experience with DCCP yet.

Furthermore, with regard to the previous patch, it is now possible to limit
the number of keepalive-Responses by setting net.dccp.default.request_retries
(also a bit like in TCP).

Lastly, added documentation of all existing DCCP sysctls.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
---
 net/dccp/timer.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

(limited to 'net/dccp/timer.c')

diff --git a/net/dccp/timer.c b/net/dccp/timer.c
index bda0af639ae..7b3f16e29a9 100644
--- a/net/dccp/timer.c
+++ b/net/dccp/timer.c
@@ -15,6 +15,11 @@
 
 #include "dccp.h"
 
+/* sysctl variables governing numbers of retransmission attempts */
+int  sysctl_dccp_request_retries	__read_mostly = TCP_SYN_RETRIES;
+int  sysctl_dccp_retries1		__read_mostly = TCP_RETR1;
+int  sysctl_dccp_retries2		__read_mostly = TCP_RETR2;
+
 static void dccp_write_timer(unsigned long data);
 static void dccp_keepalive_timer(unsigned long data);
 static void dccp_delack_timer(unsigned long data);
@@ -44,11 +49,10 @@ static int dccp_write_timeout(struct sock *sk)
 	if (sk->sk_state == DCCP_REQUESTING || sk->sk_state == DCCP_PARTOPEN) {
 		if (icsk->icsk_retransmits != 0)
 			dst_negative_advice(&sk->sk_dst_cache);
-		retry_until = icsk->icsk_syn_retries ? :
-			    /* FIXME! */ 3 /* FIXME! sysctl_tcp_syn_retries */;
+		retry_until = icsk->icsk_syn_retries ?
+			    : sysctl_dccp_request_retries;
 	} else {
-		if (icsk->icsk_retransmits >=
-		     /* FIXME! sysctl_tcp_retries1 */ 5 /* FIXME! */) {
+		if (icsk->icsk_retransmits >= sysctl_dccp_retries1) {
 			/* NOTE. draft-ietf-tcpimpl-pmtud-01.txt requires pmtu
 			   black hole detection. :-(
 
@@ -72,7 +76,7 @@ static int dccp_write_timeout(struct sock *sk)
 			dst_negative_advice(&sk->sk_dst_cache);
 		}
 
-		retry_until = /* FIXME! */ 15 /* FIXME! sysctl_tcp_retries2 */;
+		retry_until = sysctl_dccp_retries2;
 		/*
 		 * FIXME: see tcp_write_timout and tcp_out_of_resources
 		 */
@@ -196,7 +200,7 @@ backoff:
 	icsk->icsk_rto = min(icsk->icsk_rto << 1, DCCP_RTO_MAX);
 	inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto,
 				  DCCP_RTO_MAX);
-	if (icsk->icsk_retransmits > 3 /* FIXME: sysctl_dccp_retries1 */)
+	if (icsk->icsk_retransmits > sysctl_dccp_retries1)
 		__sk_dst_reset(sk);
 out:;
 }
-- 
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