sctp: Update SWS avaoidance receiver side algorithm
We currently send window update SACKs every time we free up 1 PMTU
worth of data. That a lot more SACKs then necessary. Instead, we'll
now send back the actuall window every time we send a sack, and do
window-update SACKs when a fraction of the receive buffer has been
opened. The fraction is controlled with a sysctl.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index cd2e187..90876b6 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -231,6 +231,11 @@
/* Flag to indicate whether computing and verifying checksum
* is disabled. */
int checksum_disable;
+
+ /* Threshold for rwnd update SACKS. Receive buffer shifted this many
+ * bits is an indicator of when to send and window update SACK.
+ */
+ int rwnd_update_shift;
} sctp_globals;
#define sctp_rto_initial (sctp_globals.rto_initial)
@@ -267,6 +272,7 @@
#define sctp_prsctp_enable (sctp_globals.prsctp_enable)
#define sctp_auth_enable (sctp_globals.auth_enable)
#define sctp_checksum_disable (sctp_globals.checksum_disable)
+#define sctp_rwnd_upd_shift (sctp_globals.rwnd_update_shift)
/* SCTP Socket type: UDP or TCP style. */
typedef enum {