7 files changed, 91 insertions, 13 deletions

diff --git a/Documentation/networking/dccp.txt b/Documentation/networking/dccp.txt
index a8142a81038a..c2328c862e98 100644
--- a/Documentation/networking/dccp.txt
+++ b/Documentation/networking/dccp.txt
@@ -63,6 +63,47 @@ DCCP_SOCKOPT_SEND_CSCOV is for the receiver and has a different meaning: it
         coverage value are also acceptable. The higher the number, the more
         restrictive this setting (see [RFC 4340, sec. 9.2.1]).
 
+Sysctl variables
+================
+Several DCCP default parameters can be managed by the following sysctls
+(sysctl net.dccp.default or /proc/sys/net/dccp/default):
+
+request_retries
+        The number of active connection initiation retries (the number of
+        Requests minus one) before timing out. In addition, it also governs
+        the behaviour of the other, passive side: this variable also sets
+        the number of times DCCP repeats sending a Response when the initial
+        handshake does not progress from RESPOND to OPEN (i.e. when no Ack
+        is received after the initial Request).  This value should be greater
+        than 0, suggested is less than 10. Analogue of tcp_syn_retries.
+
+retries1
+        How often a DCCP Response is retransmitted until the listening DCCP
+        side considers its connecting peer dead. Analogue of tcp_retries1.
+
+retries2
+        The number of times a general DCCP packet is retransmitted. This has
+        importance for retransmitted acknowledgments and feature negotiation,
+        data packets are never retransmitted. Analogue of tcp_retries2.
+
+send_ndp = 1
+        Whether or not to send NDP count options (sec. 7.7.2).
+
+send_ackvec = 1
+        Whether or not to send Ack Vector options (sec. 11.5).
+
+ack_ratio = 2
+        The default Ack Ratio (sec. 11.3) to use.
+
+tx_ccid = 2
+        Default CCID for the sender-receiver half-connection.
+
+rx_ccid = 2
+        Default CCID for the receiver-sender half-connection.
+
+seq_window = 100
+        The initial sequence window (sec. 7.5.2).
+
 Notes
 =====
 
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 0725441621d0..2e8c5ad82793 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -614,6 +614,9 @@ enum {
         NET_DCCP_DEFAULT_ACK_RATIO   = 4,
         NET_DCCP_DEFAULT_SEND_ACKVEC = 5,
         NET_DCCP_DEFAULT_SEND_NDP    = 6,
+        NET_DCCP_DEFAULT_REQ_RETRIES = 7,
+        NET_DCCP_DEFAULT_RETRIES1    = 8,
+        NET_DCCP_DEFAULT_RETRIES2    = 9,
 };
 
 /* /proc/sys/net/ipx */
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index d5c414bf7819..e7b96074a1b1 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -64,6 +64,17 @@ extern void dccp_time_wait(struct sock *sk, int state, int timeo);
 
 #define DCCP_XMIT_TIMEO 30000 /* Time/msecs for blocking transmit per packet */
 
+/* sysctl variables for DCCP */
+extern int  sysctl_dccp_request_retries;
+extern int  sysctl_dccp_retries1;
+extern int  sysctl_dccp_retries2;
+extern int  dccp_feat_default_sequence_window;
+extern int  dccp_feat_default_rx_ccid;
+extern int  dccp_feat_default_tx_ccid;
+extern int  dccp_feat_default_ack_ratio;
+extern int  dccp_feat_default_send_ack_vector;
+extern int  dccp_feat_default_send_ndp_count;
+
 /* is seq1 < seq2 ? */
 static inline int before48(const u64 seq1, const u64 seq2)
 {
diff --git a/net/dccp/feat.h b/net/dccp/feat.h
index cee553d416ca..6048373c7186 100644
--- a/net/dccp/feat.h
+++ b/net/dccp/feat.h
@@ -26,11 +26,4 @@ extern void dccp_feat_clean(struct dccp_minisock *dmsk);
 extern int  dccp_feat_clone(struct sock *oldsk, struct sock *newsk);
 extern int  dccp_feat_init(struct dccp_minisock *dmsk);
 
-extern int  dccp_feat_default_sequence_window;
-extern int  dccp_feat_default_rx_ccid;
-extern int  dccp_feat_default_tx_ccid;
-extern int  dccp_feat_default_ack_ratio;
-extern int  dccp_feat_default_send_ack_vector;
-extern int  dccp_feat_default_send_ndp_count;
-
 #endif /* _DCCP_FEAT_H */
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index db54e557eff1..9c9c08cffdaf 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -212,6 +212,7 @@ int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized)
 
         dccp_init_xmit_timers(sk);
         icsk->icsk_rto          = DCCP_TIMEOUT_INIT;
+        icsk->icsk_syn_retries  = sysctl_dccp_request_retries;
         sk->sk_state            = DCCP_CLOSED;
         sk->sk_write_space      = dccp_write_space;
         icsk->icsk_sync_mss     = dccp_sync_mss;
diff --git a/net/dccp/sysctl.c b/net/dccp/sysctl.c
index 38bc157876f3..7b09f2179985 100644
--- a/net/dccp/sysctl.c
+++ b/net/dccp/sysctl.c
@@ -11,6 +11,7 @@
 
 #include <linux/mm.h>
 #include <linux/sysctl.h>
+#include "dccp.h"
 #include "feat.h"
 
 #ifndef CONFIG_SYSCTL
@@ -66,6 +67,30 @@ static struct ctl_table dccp_default_table[] = {
                 .mode           = 0644,
                 .proc_handler   = proc_dointvec,
         },
+        {
+                .ctl_name       = NET_DCCP_DEFAULT_REQ_RETRIES,
+                .procname       = "request_retries",
+                .data           = &sysctl_dccp_request_retries,
+                .maxlen         = sizeof(sysctl_dccp_request_retries),
+                .mode           = 0644,
+                .proc_handler   = proc_dointvec,
+        },
+        {
+                .ctl_name       = NET_DCCP_DEFAULT_RETRIES1,
+                .procname       = "retries1",
+                .data           = &sysctl_dccp_retries1,
+                .maxlen         = sizeof(sysctl_dccp_retries1),
+                .mode           = 0644,
+                .proc_handler   = proc_dointvec,
+        },
+        {
+                .ctl_name       = NET_DCCP_DEFAULT_RETRIES2,
+                .procname       = "retries2",
+                .data           = &sysctl_dccp_retries2,
+                .maxlen         = sizeof(sysctl_dccp_retries2),
+                .mode           = 0644,
+                .proc_handler   = proc_dointvec,
+        },
         { .ctl_name = 0, }
 };
 
diff --git a/net/dccp/timer.c b/net/dccp/timer.c
index bda0af639ae4..7b3f16e29a97 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:;
 }