Commit 33155bac authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by David S. Miller

docs: networking: convert dccp.txt to ReST

- add SPDX header;
- adjust title markup;
- comment out text-only TOC from html/pdf output;
- mark code blocks and literals as such;
- adjust identation, whitespaces and blank lines;
- add to networking/index.rst.
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9a9891fb
.. SPDX-License-Identifier: GPL-2.0
=============
DCCP protocol
=============
Contents
========
- Introduction
- Missing features
- Socket options
- Sysctl variables
- IOCTLs
- Other tunables
- Notes
.. Contents
- Introduction
- Missing features
- Socket options
- Sysctl variables
- IOCTLs
- Other tunables
- Notes
Introduction
......@@ -38,6 +40,7 @@ The Linux DCCP implementation does not currently support all the features that a
specified in RFCs 4340...42.
The known bugs are at:
http://www.linuxfoundation.org/collaborate/workgroups/networking/todo#DCCP
For more up-to-date versions of the DCCP implementation, please consider using
......@@ -54,7 +57,8 @@ defined: the "simple" policy (DCCPQ_POLICY_SIMPLE), which does nothing special,
and a priority-based variant (DCCPQ_POLICY_PRIO). The latter allows to pass an
u32 priority value as ancillary data to sendmsg(), where higher numbers indicate
a higher packet priority (similar to SO_PRIORITY). This ancillary data needs to
be formatted using a cmsg(3) message header filled in as follows:
be formatted using a cmsg(3) message header filled in as follows::
cmsg->cmsg_level = SOL_DCCP;
cmsg->cmsg_type = DCCP_SCM_PRIORITY;
cmsg->cmsg_len = CMSG_LEN(sizeof(uint32_t)); /* or CMSG_LEN(4) */
......@@ -94,7 +98,7 @@ must be registered on the socket before calling connect() or listen().
DCCP_SOCKOPT_TX_CCID is read/write. It returns the current CCID (if set) or sets
the preference list for the TX CCID, using the same format as DCCP_SOCKOPT_CCID.
Please note that the getsockopt argument type here is `int', not uint8_t.
Please note that the getsockopt argument type here is ``int``, not uint8_t.
DCCP_SOCKOPT_RX_CCID is analogous to DCCP_SOCKOPT_TX_CCID, but for the RX CCID.
......@@ -113,6 +117,7 @@ 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_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.
......@@ -123,11 +128,13 @@ DCCP_SOCKOPT_RECV_CSCOV is for the receiver and has a different meaning: it
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.
DCCP_SOCKOPT_CCID_RX_INFO
Returns a `struct tfrc_rx_info' in optval; the buffer for optval and
Returns a ``struct tfrc_rx_info`` in optval; the buffer for optval and
optlen must be set to at least sizeof(struct tfrc_rx_info).
DCCP_SOCKOPT_CCID_TX_INFO
Returns a `struct tfrc_tx_info' in optval; the buffer for optval and
Returns a ``struct tfrc_tx_info`` in optval; the buffer for optval and
optlen must be set to at least sizeof(struct tfrc_tx_info).
On unidirectional connections it is useful to close the unused half-connection
......@@ -182,7 +189,7 @@ sync_ratelimit = 125 ms
IOCTLS
======
FIONREAD
Works as in udp(7): returns in the `int' argument pointer the size of
Works as in udp(7): returns in the ``int`` argument pointer the size of
the next pending datagram in bytes, or 0 when no datagram is pending.
......@@ -191,10 +198,12 @@ Other tunables
Per-route rto_min support
CCID-2 supports the RTAX_RTO_MIN per-route setting for the minimum value
of the RTO timer. This setting can be modified via the 'rto_min' option
of iproute2; for example:
of iproute2; for example::
> ip route change 10.0.0.0/24 rto_min 250j dev wlan0
> ip route add 10.0.0.254/32 rto_min 800j dev wlan0
> ip route show dev wlan0
CCID-3 also supports the rto_min setting: it is used to define the lower
bound for the expiry of the nofeedback timer. This can be useful on LANs
with very low RTTs (e.g., loopback, Gbit ethernet).
......
......@@ -48,6 +48,7 @@ Contents:
cdc_mbim
cops
cxacru
dccp
.. only:: subproject and html
......
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