From e7937772d7a2b0127cc4cbc67bc594e139fdaf63 Mon Sep 17 00:00:00 2001 From: Gerrit Renker Date: Thu, 4 Sep 2008 07:30:19 +0200 Subject: dccp: Extend CCID packet dequeueing interface This extends the packet dequeuing interface of dccp_write_xmit() to allow 1. CCIDs to take care of timing when the next packet may be sent; 2. delayed sending (as before, with an inter-packet gap up to 65.535 seconds). The main purpose is to take CCID2 out of its polling mode (when it is network- limited, it tries every millisecond to send, without interruption). The interface can also be used to support other CCIDs. The mode of operation for (2) is as follows: * new packet is enqueued via dccp_sendmsg() => dccp_write_xmit(), * ccid_hc_tx_send_packet() detects that it may not send (e.g. window full), * it signals this condition via `CCID_PACKET_WILL_DEQUEUE_LATER', * dccp_write_xmit() returns without further action; * after some time the wait-condition for CCID becomes true, * that CCID schedules the tasklet, * tasklet function calls ccid_hc_tx_send_packet() via dccp_write_xmit(), * since the wait-condition is now true, ccid_hc_tx_packet() returns "send now", * packet is sent, and possibly more (since dccp_write_xmit() loops). Code reuse: the taskled function calls dccp_write_xmit(), the timer function reduces to a wrapper around the same code. If the tasklet finds that the socket is locked, it re-schedules the tasklet function (not the tasklet) after one jiffy. Changed DCCP_BUG to dccp_pr_debug when transmit_skb returns an error (e.g. when a local qdisc is used, NET_XMIT_DROP=1 can be returned for many packets). Signed-off-by: Gerrit Renker --- include/linux/dccp.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/dccp.h b/include/linux/dccp.h index 83197b601a4..eed52bcd35d 100644 --- a/include/linux/dccp.h +++ b/include/linux/dccp.h @@ -463,7 +463,8 @@ struct dccp_ackvec; * @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_xmit_timer - timer for when CCID is not ready to send + * @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) */ struct dccp_sock { @@ -504,6 +505,7 @@ struct dccp_sock { __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; }; -- cgit v1.2.3