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Various textual improvements.

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This commit is contained in:
keramida 2006-03-05 15:54:22 +00:00
parent ffede784ae
commit cdffa6c05c
1 changed files with 15 additions and 16 deletions
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31
share/man/man4/netgraph.4
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@ -110,10 +110,9 @@ characters (including the terminating
.Dv NUL .Dv NUL
character). character).
.Pp .Pp
Each node instance has a unique Each node instance has a unique 32-bit
.Em ID number .Em ID number .
which is expressed as a 32-bit hexadecimal value. This number may be used to refer to a node when there is no
This value may be used to refer to a node when there is no
.Tn ASCII .Tn ASCII
name assigned to it. name assigned to it.
.Ss Hooks .Ss Hooks
@ -153,7 +152,7 @@ by the input queueing system, rather than being delivered directly.
This can be used when the data is sent from an interrupt handler, This can be used when the data is sent from an interrupt handler,
and processing must be quick so as not to block other interrupts. and processing must be quick so as not to block other interrupts.
.It .It
A hook may supply overriding receive data and receive message functions A hook may supply overriding receive data and receive message functions,
which should be used for data and messages received through that hook which should be used for data and messages received through that hook
in preference to the general node-wide methods. in preference to the general node-wide methods.
.El .El
@ -175,15 +174,15 @@ The first
in a chain must have the in a chain must have the
.Dv M_PKTHDR .Dv M_PKTHDR
flag set. flag set.
Each node decides how to handle data coming in on its hooks. Each node decides how to handle data received through one of its hooks.
.Pp .Pp
Along with data, nodes can also receive control messages. Along with data, nodes can also receive control messages.
There are generic and type-specific control messages. There are generic and type-specific control messages.
Control messages have a common Control messages have a common
header format, followed by a type-specific data, and are binary structures header format, followed by type-specific data, and are binary structures
for efficiency. for efficiency.
However, node types may also support conversion of the However, node types may also support conversion of the
type specific data between binary and type-specific data between binary and
.Tn ASCII .Tn ASCII
formats, formats,
for debugging and human interface purposes (see the for debugging and human interface purposes (see the
@ -205,10 +204,10 @@ addressing).
If the destination is adjacent to the source, then the source If the destination is adjacent to the source, then the source
node may simply specify (as a pointer in the code) the hook across which the node may simply specify (as a pointer in the code) the hook across which the
message should be sent. message should be sent.
Otherwise, the recipient node global Otherwise, the recipient node's global
.Tn ASCII .Tn ASCII
name name
(or equivalent ID based name) is used as the destination address (or equivalent node ID) is used as the destination address
for the message (absolute addressing). for the message (absolute addressing).
The two types of The two types of
.Tn ASCII .Tn ASCII
@ -217,19 +216,19 @@ may be combined, by specifying an absolute start node and a sequence
of hooks. of hooks.
Only the Only the
.Tn ASCII .Tn ASCII
addressing modes are available to control programs outside the kernel, addressing modes are available to control programs outside the kernel;
as use of direct pointers is limited of course to kernel modules. use of direct pointers is limited to kernel modules.
.Pp .Pp
Messages often represent commands that are followed by a reply message Messages often represent commands which are followed by a reply message
in the reverse direction. in the reverse direction.
To facilitate this, the recipient of a To facilitate this, the recipient of a
control message is supplied with a control message is supplied with a
.Dq return address .Dq return address
that is suitable for addressing a reply. that is suitable for addressing a reply.
.Pp .Pp
Each control message contains a 32 bit value called a Each control message contains a 32-bit value, called a
.Em typecookie .Dq typecookie ,
indicating the type of the message, i.e., how to interpret it. indicating the type of the message, i.e. how to interpret it.
Typically each type defines a unique typecookie for the messages Typically each type defines a unique typecookie for the messages
that it understands. that it understands.
However, a node may choose to recognize and However, a node may choose to recognize and