[NET]: The scheduled removal of the frame diverter.

[linux-2.6] / Documentation / networking / dccp.txt

diff --git a/Documentation/networking/dccp.txt b/Documentation/networking/dccp.txt
index 74563b38ffd90cdd59a48619fb7a7b46f6ec798a..c2328c862e987f76e389aedce965face2dec2829 100644 (file)
--- a/Documentation/networking/dccp.txt
+++ b/Documentation/networking/dccp.txt
@@ -47,6 +47,63 @@ the socket will fall back to 0 (which means that no meaningful service code
 is present). Connecting sockets set at most one service option; for
 listening sockets, multiple service codes can be specified.
 
+DCCP_SOCKOPT_SEND_CSCOV and DCCP_SOCKOPT_RECV_CSCOV are used for setting the
+partial checksum coverage (RFC 4340, sec. 9.2). The default is that checksums
+always cover the entire packet and that only fully covered application data is
+accepted by the receiver. Hence, when using this feature on the sender, it must
+be enabled at the receiver, too with suitable choice of CsCov.
+
+DCCP_SOCKOPT_SEND_CSCOV sets the sender checksum coverage. Values in the
+       range 0..15 are acceptable. The default setting is 0 (full coverage),
+       values between 1..15 indicate partial coverage.
+DCCP_SOCKOPT_SEND_CSCOV is for the receiver and has a different meaning: it
+       sets a threshold, where again values 0..15 are acceptable. The default
+       of 0 means that all packets with a partial coverage will be discarded.
+       Values in the range 1..15 indicate that packets with minimally such a
+       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
 =====