From d83447f0944e73d690218d79c07762ffa4ceb9e4 Mon Sep 17 00:00:00 2001 From: Gerrit Renker Date: Sun, 14 Nov 2010 17:25:46 +0100 Subject: 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 --- include/linux/dccp.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/dccp.h') 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; }; -- cgit v1.2.2 From 871a2c16c21b988688b4ab1a78eadd969765c0a3 Mon Sep 17 00:00:00 2001 From: Tomasz Grobelny Date: Sat, 4 Dec 2010 13:38:01 +0100 Subject: dccp: Policy-based packet dequeueing infrastructure This patch adds a generic infrastructure for policy-based dequeueing of TX packets and provides two policies: * a simple FIFO policy (which is the default) and * a priority based policy (set via socket options). Both policies honour the tx_qlen sysctl for the maximum size of the write queue (can be overridden via socket options). The priority policy uses skb->priority internally to assign an u32 priority identifier, using the same ranking as SO_PRIORITY. The skb->priority field is set to 0 when the packet leaves DCCP. The priority is supplied as ancillary data using cmsg(3), the patch also provides the requisite parsing routines. Signed-off-by: Tomasz Grobelny Signed-off-by: Gerrit Renker --- include/linux/dccp.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'include/linux/dccp.h') diff --git a/include/linux/dccp.h b/include/linux/dccp.h index eed52bcd35d0..010e2d87ed75 100644 --- a/include/linux/dccp.h +++ b/include/linux/dccp.h @@ -197,6 +197,21 @@ enum dccp_feature_numbers { DCCPF_MAX_CCID_SPECIFIC = 255, }; +/* DCCP socket control message types for cmsg */ +enum dccp_cmsg_type { + DCCP_SCM_PRIORITY = 1, + DCCP_SCM_QPOLICY_MAX = 0xFFFF, + /* ^-- Up to here reserved exclusively for qpolicy parameters */ + DCCP_SCM_MAX +}; + +/* DCCP priorities for outgoing/queued packets */ +enum dccp_packet_dequeueing_policy { + DCCPQ_POLICY_SIMPLE, + DCCPQ_POLICY_PRIO, + DCCPQ_POLICY_MAX +}; + /* DCCP socket options */ #define DCCP_SOCKOPT_PACKET_SIZE 1 /* XXX deprecated, without effect */ #define DCCP_SOCKOPT_SERVICE 2 @@ -210,6 +225,8 @@ enum dccp_feature_numbers { #define DCCP_SOCKOPT_CCID 13 #define DCCP_SOCKOPT_TX_CCID 14 #define DCCP_SOCKOPT_RX_CCID 15 +#define DCCP_SOCKOPT_QPOLICY_ID 16 +#define DCCP_SOCKOPT_QPOLICY_TXQLEN 17 #define DCCP_SOCKOPT_CCID_RX_INFO 128 #define DCCP_SOCKOPT_CCID_TX_INFO 192 @@ -458,6 +475,8 @@ struct dccp_ackvec; * @dccps_hc_rx_ccid - CCID used for the receiver (or receiving half-connection) * @dccps_hc_tx_ccid - CCID used for the sender (or sending half-connection) * @dccps_options_received - parsed set of retrieved options + * @dccps_qpolicy - TX dequeueing policy, one of %dccp_packet_dequeueing_policy + * @dccps_tx_qlen - maximum length of the TX queue * @dccps_role - role of this sock, one of %dccp_role * @dccps_hc_rx_insert_options - receiver wants to add options when acking * @dccps_hc_tx_insert_options - sender wants to add options when sending @@ -500,6 +519,8 @@ struct dccp_sock { struct ccid *dccps_hc_rx_ccid; struct ccid *dccps_hc_tx_ccid; struct dccp_options_received dccps_options_received; + __u8 dccps_qpolicy; + __u32 dccps_tx_qlen; enum dccp_role dccps_role:2; __u8 dccps_hc_rx_insert_options:1; __u8 dccps_hc_tx_insert_options:1; -- cgit v1.2.2