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docs: networking: convert strparser.txt to ReST 

- add SPDX header;
- adjust title markup;
- mark code blocks and literals as such;
- mark tables as such;
- adjust identation, whitespaces and blank lines where needed;
- add to networking/index.rst.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Mauro Carvalho Chehab 2020-04-30 18:04:26 +02:00 committed by David S. Miller
parent fe3dfe418c
commit 060d9d3e12
2 changed files with 60 additions and 26 deletions
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1
Documentation/networking/index.rst
View File

@ -104,6 +104,7 @@ Contents:
secid
seg6-sysctl
skfp
strparser
.. only:: subproject and html

85
Documentation/networking/strparser.txt → Documentation/networking/strparser.rst
View File

@ -1,4 +1,8 @@
.. SPDX-License-Identifier: GPL-2.0
=========================
Stream Parser (strparser)
=========================
Introduction
============
@ -34,8 +38,10 @@ that is called when a full message has been completed.
Functions
=========
strp_init(struct strparser *strp, struct sock *sk,
const struct strp_callbacks *cb)
::
strp_init(struct strparser *strp, struct sock *sk,
const struct strp_callbacks *cb)
Called to initialize a stream parser. strp is a struct of type
strparser that is allocated by the upper layer. sk is the TCP
@ -43,31 +49,41 @@ strp_init(struct strparser *strp, struct sock *sk,
callback mode; in general mode this is set to NULL. Callbacks
are called by the stream parser (the callbacks are listed below).
void strp_pause(struct strparser *strp)
::
void strp_pause(struct strparser *strp)
Temporarily pause a stream parser. Message parsing is suspended
and no new messages are delivered to the upper layer.
void strp_unpause(struct strparser *strp)
::
void strp_unpause(struct strparser *strp)
Unpause a paused stream parser.
void strp_stop(struct strparser *strp);
::
void strp_stop(struct strparser *strp);
strp_stop is called to completely stop stream parser operations.
This is called internally when the stream parser encounters an
error, and it is called from the upper layer to stop parsing
operations.
void strp_done(struct strparser *strp);
::
void strp_done(struct strparser *strp);
strp_done is called to release any resources held by the stream
parser instance. This must be called after the stream processor
has been stopped.
int strp_process(struct strparser *strp, struct sk_buff *orig_skb,
unsigned int orig_offset, size_t orig_len,
size_t max_msg_size, long timeo)
::
int strp_process(struct strparser *strp, struct sk_buff *orig_skb,
unsigned int orig_offset, size_t orig_len,
size_t max_msg_size, long timeo)
strp_process is called in general mode for a stream parser to
parse an sk_buff. The number of bytes processed or a negative
@ -75,7 +91,9 @@ int strp_process(struct strparser *strp, struct sk_buff *orig_skb,
consume the sk_buff. max_msg_size is maximum size the stream
parser will parse. timeo is timeout for completing a message.
void strp_data_ready(struct strparser *strp);
::
void strp_data_ready(struct strparser *strp);
The upper layer calls strp_tcp_data_ready when data is ready on
the lower socket for strparser to process. This should be called
@ -83,7 +101,9 @@ void strp_data_ready(struct strparser *strp);
maximum messages size is the limit of the receive socket
buffer and message timeout is the receive timeout for the socket.
void strp_check_rcv(struct strparser *strp);
::
void strp_check_rcv(struct strparser *strp);
strp_check_rcv is called to check for new messages on the socket.
This is normally called at initialization of a stream parser
@ -94,7 +114,9 @@ Callbacks
There are six callbacks:
int (*parse_msg)(struct strparser *strp, struct sk_buff *skb);
::
int (*parse_msg)(struct strparser *strp, struct sk_buff *skb);
parse_msg is called to determine the length of the next message
in the stream. The upper layer must implement this function. It
@ -107,14 +129,16 @@ int (*parse_msg)(struct strparser *strp, struct sk_buff *skb);
The return values of this function are:
>0 : indicates length of successfully parsed message
0 : indicates more data must be received to parse the message
-ESTRPIPE : current message should not be processed by the
kernel, return control of the socket to userspace which
can proceed to read the messages itself
other < 0 : Error in parsing, give control back to userspace
assuming that synchronization is lost and the stream
is unrecoverable (application expected to close TCP socket)
========= ===========================================================
>0 indicates length of successfully parsed message
0 indicates more data must be received to parse the message
-ESTRPIPE current message should not be processed by the
kernel, return control of the socket to userspace which
can proceed to read the messages itself
other < 0 Error in parsing, give control back to userspace
assuming that synchronization is lost and the stream
is unrecoverable (application expected to close TCP socket)
========= ===========================================================
In the case that an error is returned (return value is less than
zero) and the parser is in receive callback mode, then it will set
@ -123,7 +147,9 @@ int (*parse_msg)(struct strparser *strp, struct sk_buff *skb);
the current message, then the error set on the attached socket is
ENODATA since the stream is unrecoverable in that case.
void (*lock)(struct strparser *strp)
::
void (*lock)(struct strparser *strp)
The lock callback is called to lock the strp structure when
the strparser is performing an asynchronous operation (such as
@ -131,14 +157,18 @@ void (*lock)(struct strparser *strp)
function is to lock_sock for the associated socket. In general
mode the callback must be set appropriately.
void (*unlock)(struct strparser *strp)
::
void (*unlock)(struct strparser *strp)
The unlock callback is called to release the lock obtained
by the lock callback. In receive callback mode the default
function is release_sock for the associated socket. In general
mode the callback must be set appropriately.
void (*rcv_msg)(struct strparser *strp, struct sk_buff *skb);
::
void (*rcv_msg)(struct strparser *strp, struct sk_buff *skb);
rcv_msg is called when a full message has been received and
is queued. The callee must consume the sk_buff; it can
@ -152,7 +182,9 @@ void (*rcv_msg)(struct strparser *strp, struct sk_buff *skb);
the length of the message. skb->len - offset may be greater
then full_len since strparser does not trim the skb.
int (*read_sock_done)(struct strparser *strp, int err);
::
int (*read_sock_done)(struct strparser *strp, int err);
read_sock_done is called when the stream parser is done reading
the TCP socket in receive callback mode. The stream parser may
@ -160,7 +192,9 @@ int (*read_sock_done)(struct strparser *strp, int err);
to occur when exiting the loop. If the callback is not set (NULL
in strp_init) a default function is used.
void (*abort_parser)(struct strparser *strp, int err);
::
void (*abort_parser)(struct strparser *strp, int err);
This function is called when stream parser encounters an error
in parsing. The default function stops the stream parser and
@ -204,4 +238,3 @@ Author
======
Tom Herbert (tom@quantonium.net)