1 files changed, 16 insertions, 0 deletions

diff --git a/Documentation/networking/dccp.txt b/Documentation/networking/dccp.txt
index 74563b38ffd9..a8142a81038a 100644
--- a/Documentation/networking/dccp.txt
+++ b/Documentation/networking/dccp.txt
@@ -47,6 +47,22 @@ 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]).
+
 Notes
 =====