diff options
Diffstat (limited to 'Documentation/networking/dccp.txt')
| -rw-r--r-- | Documentation/networking/dccp.txt | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/Documentation/networking/dccp.txt b/Documentation/networking/dccp.txt index 4504cc59e405..afb66f9a8aff 100644 --- a/Documentation/networking/dccp.txt +++ b/Documentation/networking/dccp.txt @@ -38,8 +38,13 @@ Socket options DCCP_SOCKOPT_SERVICE sets the service. The specification mandates use of service codes (RFC 4340, sec. 8.1.2); if this socket option is not set, 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. +is present). On active sockets this is set before connect(); specifying more +than one code has no effect (all subsequent service codes are ignored). The +case is different for passive sockets, where multiple service codes (up to 32) +can be set before calling bind(). + +DCCP_SOCKOPT_GET_CUR_MPS is read-only and retrieves the current maximum packet +size (application payload size) in bytes, see RFC 4340, section 14. 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 @@ -50,12 +55,13 @@ 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 +DCCP_SOCKOPT_RECV_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]). + restrictive this setting (see [RFC 4340, sec. 9.2.1]). Partial coverage + settings are inherited to the child socket after accept(). The following two options apply to CCID 3 exclusively and are getsockopt()-only. In either case, a TFRC info struct (defined in <linux/tfrc.h>) is returned. @@ -112,9 +118,14 @@ tx_qlen = 5 The size of the transmit buffer in packets. A value of 0 corresponds to an unbounded transmit buffer. +sync_ratelimit = 125 ms + The timeout between subsequent DCCP-Sync packets sent in response to + sequence-invalid packets on the same socket (RFC 4340, 7.5.4). The unit + of this parameter is milliseconds; a value of 0 disables rate-limiting. + Notes ===== DCCP does not travel through NAT successfully at present on many boxes. This is -because the checksum covers the psuedo-header as per TCP and UDP. Linux NAT +because the checksum covers the pseudo-header as per TCP and UDP. Linux NAT support for DCCP has been added. |