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authorGerrit Renker <gerrit@erg.abdn.ac.uk>2010-11-14 17:25:46 +0100
committerGerrit Renker <gerrit@erg.abdn.ac.uk>2010-11-15 07:12:00 +0100
commitd83447f0944e73d690218d79c07762ffa4ceb9e4 (patch)
tree2a9adf943eee50d8c495ac9302692a277d862d92 /include/linux/dccp.h
parent18219463c884bfdb7954d298b9edb5194b14d621 (diff)
dccp ccid-2: Schedule Sync as out-of-band mechanism
The problem with Ack Vectors is that i) their length is variable and can in principle grow quite large, ii) it is hard to predict exactly how large they will be. Due to the second point it seems not a good idea to reduce the MPS; in particular when on average there is enough room for the Ack Vector and an increase in length is momentarily due to some burst loss, after which the Ack Vector returns to its normal/average length. The solution taken by this patch is to subtract a minimum-expected Ack Vector length from the MPS, and to defer any larger Ack Vectors onto a separate Sync - but only if indeed there is no space left on the skb. This patch provides the infrastructure to schedule Sync-packets for transporting (urgent) out-of-band data. Its signalling is quicker than scheduling an Ack, since it does not need to wait for new application data. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Diffstat (limited to 'include/linux/dccp.h')
-rw-r--r--include/linux/dccp.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/dccp.h b/include/linux/dccp.h
index 749f01ccd26e..eed52bcd35d0 100644
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -462,6 +462,7 @@ struct dccp_ackvec;
* @dccps_hc_rx_insert_options - receiver wants to add options when acking
* @dccps_hc_tx_insert_options - sender wants to add options when sending
* @dccps_server_timewait - server holds timewait state on close (RFC 4340, 8.3)
+ * @dccps_sync_scheduled - flag which signals "send out-of-band message soon"
* @dccps_xmitlet - tasklet scheduled by the TX CCID to dequeue data packets
* @dccps_xmit_timer - used by the TX CCID to delay sending (rate-based pacing)
* @dccps_syn_rtt - RTT sample from Request/Response exchange (in usecs)
@@ -503,6 +504,7 @@ struct dccp_sock {
__u8 dccps_hc_rx_insert_options:1;
__u8 dccps_hc_tx_insert_options:1;
__u8 dccps_server_timewait:1;
+ __u8 dccps_sync_scheduled:1;
struct tasklet_struct dccps_xmitlet;
struct timer_list dccps_xmit_timer;
};