SNETD(1M)SNETD(1M)NAMEsnetd - DLPI network daemon
SYNOPSISsnetd [-nt] [ config_file | - ]
DESCRIPTIONsnetd configures a STREAMS network from a specification given in a
configuration file whose format is described in the Configuration
section.
By default the configuration is taken from the file
/etc/config/snetd.options. An alternative file may be specified as a
command line argument (config_file). The special filename '-' is taken
to mean the standard input.
Upon system startup, if the state of the snetd daemon is on, the daemon
is started by /etc/init.d/network. You may use chkconfig(1M) to check the
state of the daemon or to change its state.
The -t option may be used to debug a configuration file. It produces
trace information indicating the sequence of opens, links, etc. performed
by snetd to create the STREAMS architecture defined by the configuration.
The -n option, which also implies -t , inhibits the actual building of
the STREAMS network.
CONFIGURATION
This section describes the configuration of the STREAMS network
constructed by snetd.
The file is in two sections, module and streams , separated by a line
consisting of the character sequence '%%'. Blank lines may be used
freely throughout the file, and a token (see below) beginning with an
unquoted '#' (hash) denotes a comment which lasts till the end of the
line. In addition, a backslash (\) immediately preceding the end of a
line results in the newline being treated as whitespace (except at the
end of comment lines).
Tokens consist either of
a) a single occurrence of the special characters { '=', '{', ',', '}' }
(Note: '=' is not a special character within the brace-enclosed argument
list of a control message; ',' is only a special character in this
position.)
b) strings of arbitrary characters enclosed in single or double quotes
(''' or '"'), but not containing a newline - each quoting character
quotes the other, for example, "foo 'bar'" or '"foo" bar'
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(Newlines occurring within quoted strings will silently terminate the
string.)
c) sequences of non-whitespace characters not including any of the
special characters or quotes
All strings are case-sensitive, and are silently truncated to 200
characters.
The modules section describes the individual modules and drivers from
which the STREAMS network configuration will be built.
tcp dc /dev/tcp
arp m arp
x25 dc /dev/x25
lapb0 dc /dev/lapb0
Each line (such as the examples above) consists of three tokens
(separated by whitespace or tabs) as follows.
The module identifier is the name by which the module or driver will be
known in the streams section (see below).
The module type is a sequence of character flags describing the module or
driver. The flag 'd' describes a STREAMS driver , whereas 'm' describes
a module. The 'c' flag specifies a driver to be cloneable. (See the
STREAMS Programmer's Guide for a detailed description of modules and
drivers.)
The module name is the character device name for a driver, or the
pushable module name for a module.
The streams section describes the architecture of the network in terms of
how the previously defined modules and drivers are to be combined (by
means of the appropriate PUSHes and LINKs) into streams. Multiplexing
and cloning are handled automatically by the snetd(1M) utility.
ip arp IP_NET=89.0.0.3
x25 lapb0 SHELL="x25tune -P -s A def.dte.x25" \
X25_SET_SNID={A, LC_LAPBDTE, , }
Lines in this section (such as the above examples) are of the following
form.
The first two tokens on a line are names (module identifiers as defined
in the previous section) of drivers or modules which are to form the
upstream and downstream components respectively of a STREAMS link.
Each link performed between token 1 and token 2 generates a mux_id
(multiplexing identifier) which is associated with that link. It is
possible to override the generated link by replacing token 2 with an
explicit mux_id, for example:
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lapb0 1 LL_SET_SNID=A \
SHELL="lltune -P -p lapb -s B -d /dev/lapb0 def.lapb"
This sets the mux_id associated with the link to 1 .
These names may be qualified by a suffix consisting of a colon (:) and a
number (for example arp:1) to signify a particular instantiation of a
module. (An uninstantiated name is an abbreviation for name:0.) Each
instantiation of a module can be thought of as a separate block in a
STREAMS Architecture diagram. Separate instantiations would be
appropriate for, say, a module pushed above more than one driver, but not
for a cloneable multiplexed driver.
Instantiations are used in the 'streams' section only, to instantiate
modules defined in the 'modules' section. The following networking
example would run IP over two distinct networks:
ip dc /dev/ip
arp m arp
ethr0 dc /dev/ethr0
ethr1 dc /dev/ethr1
%%
ip arp:0 IP_NET=89.0.0.1
arp:0 ethr0 ARP_TYPE
ip arp:1 IP_NET=89.0.0.2
arp:1 ethr1 ARP_TYPE
The remainder of each line consists of a (possibly null) sequence of
control actions to be performed on completion of the link in the order
specified.
Each control action is of the form function = argument-list, where the
argument-list is either a single string argument or a comma-separated
list enclosed in braces ({ and }). Control actions requiring no
arguments may consist simply of the function component. Arguments
containing whitespace or any of the special characters listed above must
be quoted.
The following control actions are currently defined:
IP_NET={internet-address, subnet-mask, forwb=boolean}
This specifies the network address and subnet mask
for a stream below IP, and whether broadcasts are to
be forwarded from other networks to that network.
This is typically used when a network is multiplexed
below an IP (Internet Protocol) driver. The Internet
address and Subnet mask are given in standard
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Internet dot format, and may be omitted (supplied as
a null string) when not relevant, in which case they
will be passed as zero. The broadcast flag is
specified as a boolean value: y or n (for
'yes'/'true' - 'do forward' - or 'no'/'false' -
'don't forward'), or may be omitted in the default
case (don't forward).
Note: A broadcast packet for transmission to a
network either originates from the host or has
previously been received from another network. The
first type is always transmitted. The second type is
only transmitted if the forward broadcast flag forwb
is set to 'y'. This flag is only relevant when using
gateways.
In cases where only the network address is supplied,
the following syntax may be used
IP_NET=internet-address
ARP_TYPE=trailers
This specifies that this stream is to be registered
with the network driver below as the stream on which
incoming IP packets are to be received.
In addition, trailers may take the value trailers or
notrailers (the default), to specify whether trailer
encapsulated packets should be sent on the network
interface.
LL_SET_SNID=subnet-id
This registers the subnetwork identifier (subnet-id)
to be associated with this link. The subnetwork
identifier provides a unique name for an outlet to a
board and its associated higher level streams. It is
a single alphanumeric character and is a mandatory
parameter. The subnet-id correspond to the
associated minor device number , ie. minor 0 is 'A',
minor 1 is 'B', etc.
X25_SET_SNID={subnet-id, class, local-SAP, loop-SAP}
This registers the subnetwork identifier to be
associated with this link, the class of the network
below the link, and the local- and loop-SAPs to be
associated with this subnetwork.
The class can be one of the following:
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LC_LLC1 LLC-1,
LC_LLC2 LLC-2,
LC_LAPBDTE LAPB - DTE,
LC_LAPBXDTE LAPB - DTE and extended addressing,
LC_LAPBDCE LAPB - DCE,
LC_LAPBXCDE LAPB - DCE and extended addressing.
LC_LAPDTE LAP - DTE,
LC_LAPDCE LAP - DCE,
The SAPs are only required for classes 'LC_LLC2' and
'LC_LLC1'. They are two digit hexadecimal numbers.
The SAPs must be even, non-zero and different. If
the class is 'LC_LLC2', and the SAPs are not present,
the defaults for local and loop SAPs are 0x7E and
0x70 respectively. If the class is 'LC_LLC1', and
the SAP is not present, the default for local SAP is
0x7E. For any other class, the SAPs are not used.
The subnet-id and class parameters are mandatory, but
the local-SAP and loop-SAP parameters are optional.
The subnet-id correspond to the associated minor
device number , ie. minor 0 is 'A', minor 1 is 'B',
etc.
SHELL="command-string"
This allows calls to the shell. Utilities may then
be called at an intermediate stage in the building of
the STREAMS network. For example:
ip - SHELL=" ixemap -Z; ixemap -P "
This particular shell call to the ixemap(1M) utility
deals with the IXE module internal table of X.25 and
Internet address associations (as described in
ixemapconf(4)).
A special dummy link exists, where no link is formed,
but the control action is executed. This occurs when
token 2 is a hyphen ( '-' ) .
For example:
x25 - SHELL="pvcmap -P"
which is simply a shell call to execute pvcmap .
EXAMPLES
When the DLPI subsystem is installed, a sample configuration file is
installed at /etc/config/snetd.options, if the file does not already
exist. The file contains sample configuration lines for three
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interfaces: one token ring interface, one ethernet interface and one fddi
interface. As 'sample' configuration lines, the configuration lines are
commented out with an '#' sign at column one. To activate a particular
interface, the '#' signs must be removed. The sample configuration file
installed by the product might contain the following network description
depending on your system configuration. Please note that the line
numbers will not be in the shipped file but they are put in here for
reference purposes.
/*line1*/ #fv0 d /dev/fv0
/*line2*/ #ec0 d /dev/ec0
/*line3*/ #ipg0 d /dev/ipg0
/*line4*/ llc2 dc /dev/llc2
/*line5*/
/*line6*/ %%
/*line7*/
/*line8*/ #llc2 fv0 LL_SET_SNID=A \
/*line9*/ # SHELL="lltune -P -p llc2 -s A -d /dev/llc2 def.tokenring"
/*line10*/#llc2 ec0 LL_SET_SNID=B \
/*line11*/# SHELL="lltune -P -p llc2 -s B -d /dev/llc2 def.ether"
/*line12*/#llc2 ipg0 LL_SET_SNID=C \
/*line13*/# SHELL="lltune -P -p llc2 -s C -d /dev/llc2 def.fddi"
To activate the token ring interface fv0, you need only take out the '#'
signs at the beginning of the line #1, #8, and #9. Line 9 is to execute
lltune(1M) command to set default LLC2 tuning parameters for this token
ring interface.
A typical configuration file for X.25 only, might contain the following
network description.
echo m echo
ec0 dc /dev/ec0
lapb dc /dev/lapb
llc2 dc /dev/llc2
wan0 dc /dev/wan0
x25 dc /dev/x25
%%
llc2 ec0 LL_SET_SNID=C \
SHELL="lltune -P -p llc2 -s C -d /dev/llc2 def.llc2"
x25 llc2 SHELL="x25tune -P -s C -d /dev/x25 -a 0000000000007E \
def.lan.x25" X25_SET_SNID={C, LC_LLC2, 7E, 70}
lapb wan0 LL_SET_SNID=A \
SHELL="wantune -P -d /dev/wan0 -s A def.wan" \
SHELL="lltune -P -p lapb -s A -d /dev/lapb def.lapb"
x25 lapb SHELL="x25tune -P -s A -d /dev/x25 def.dte80.x25" \
X25_SET_SNID={A, LC_LAPBDTE, , }
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lapb wan0 LL_SET_SNID=B \
SHELL="wantune -P -d /dev/wan0 -s B def.wan" \
SHELL="lltune -P -p lapb -s B -d /dev/lapb def.lapb"
x25 lapb SHELL="x25tune -P -s B -d /dev/x25 def.dte80.x25" \
X25_SET_SNID={B, LC_LAPBDTE, , }
x25 - SHELL="pvcmap -P"
echo ec0 ECHO_TYPE
Here, wan0 and ec0 are WAN and Ethernet drivers respectively, and your
real Ethernet driver may be ec0 , et0 , or enp0 , depending on your
system configuration. Note that the above is an example where lapb,
llc2, wan0 and ec0 are in-kernel. Instantiations are used. Each
instantiation can be thought of as a separate block in a STREAMS
Architecture diagram.
When TCP is to be run over X.25 a typical configuration file might
contain the following extra entries to cater for the IP to X.25
Encapsulation driver, IXE (see ixe(7)).
ixe dc /dev/ixe
%%
ip ixe IP_NET={15.0.0.2, 255.0.0.0, forwb=n}
ip ixe IP_NET={16.0.0.2, 255.0.0.0, forwb=n}
ixe x25
ixe x25
ixe x25
ip - SHELL="ixemap -Z" SHELL="ixemap -P" SHELL="ixetune"
FILES
/etc/config/snetd
/etc/config/snetd.options
SEE ALSOdlpi(7), lltune(1M), ixemap(1M), pvcmap(1M), ixemapconf(4), ixe(7).
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