route.8

早期freebsd实现

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.\"     @(#)route.8	6.11 (Berkeley) 3/16/91
.\"
.Dd March 16, 1991
.Dt ROUTE 8
.Os BSD 4.2
.Sh NAME
.Nm route
.Nd manually manipulate the routing tables (Interim)
.Sh SYNOPSIS
.Nm route
.Op Fl n
.Op Fl q
.Op Fl v
.Ar command
.Oo
.Op Ar modifiers
.Ar args
.Oc
.Sh DESCRIPTION
.Nm Route
is a program used to manually manipulate the network
routing tables.  It normally is not needed, as the
system routing table management daemon,
.Xr routed 8 ,
should tend to this task.
.Pp
Options supported by
.Nm route :
.Pp
.Bl -tag -width Ds
.It Fl n
Prevent attempts to print host and network names symbolically
when reporting actions.
.It Fl v
(verbose) Print additional details.
.It Fl q
Suppress all output.
.El
.Pp
Commands accepted by
.Nm route :
.Pp
.Bl -tag -width Fl -compact
.It Cm add
Add a route.
.It Cm flush
Remove all routes.
.It Cm delete
Delete a specific route.
.It Cm change
Change aspects of a route (such as its gateway).
.It Cm get
Lookup and display the route for a destination.
.It Cm monitor
Continuously report any changes to the routing information base,
routing lookup misses, or suspected network partionings.
.El
.Pp
The monitor command has the syntax
.Pp
.Bd -filled -offset indent -compact
.Nm route Op Fl n
.Cm monitor
.Ed
.Pp
The flush command has the syntax
.Pp
.Bd -filled -offset indent -compact
.Nm route Op Fl n
.Cm flush
.Op Ar family
.Ed
.Pp
Where the address family may be specified by any of the
.Fl osi ,
.Fl xns ,
or
.Fl inet
keywords.
.Pp
The other commands have the following syntax:
.Pp
.Bd -filled -offset indent -compact
.Nm route Op Fl n
.Ar command
.Op Fl net No \&| Fl host
.Ar destination gateway
.Ed
.Pp
where
.Ar destination
is the destination host or network,
.Ar gateway
is the next-hop gateway to which packets should be addressed.
Routes to a particular host are distinguished from those to
a network by interpreting the Internet address associated with
.Ar destination .
The optional keywords
.Fl net
and
.Fl host
force the destination to be interpreted as a network or a host, respectively.
Otherwise, if the 
.Ar destination
has a ``local address part'' of
INADDR_ANY ,
or if the
.Ar destination
is the symbolic name of a network, then the route is
assumed to be to a network; otherwise, it is presumed to be a
route to a host.
.Pp
For example,
.Li 128.32
is interpreted as
.Fl host Li 128.0.0.32 ;
.Li 128.32.130
is interpreted as
.Fl host Li 128.32.0.130 ;
.Fl net Li 128.32
is interpreted as
.Li 128.32.0.0;
and 
.Fl net Li 128.32.130
is interpreted as
.Li 128.32.130.0 .
.Pp
If the route is via an interface rather than
via a gateway, the 
.Fl interface
modifier should be specified;
the gateway given is the address of this host on the common network,
indicating the interface to be used for transmission.
.Pp
The optional modifiers
.Fl xns ,
and
.Fl osi
specify that all subsequent addresses are in the
.Tn XNS
or
.Tn OSI
address families,
and the names must be numeric specifications rather than
symbolic names.
.Pp
The optional
.Fl netmask
qualifier is intended
to achieve the effect of an
.Tn OSI
.Tn ESIS
redirect with the netmask option.
One specifies an additional ensuing address parameter
(to be interpreted as a network mask).
The implicit network mask generated in the inet case
can be overridden by making sure this option follows the destination parameter.
.Pp
The optional modifiers
.Fl rtt ,
.Fl rttvar ,
.Fl sendpipe ,
.Fl recvpipe ,
.Fl mtu ,
.Fl hopcount ,
.Fl expire ,
and
.Fl ssthresh
provide initial values to metrics maintained in the routing entry.
These may be individually locked by preceding each such modifier to
be locked by
the
.Fl lock
meta-modifier, or one can 
specify that all ensuing metrics may be locked by the
.Fl lockrest
meta-modifier.
.Pp
In a
.Cm change
or
.Cm add
command where the destination and gateway are not sufficient to specify
the route (as in the
.Tn ISO
case where several interfaces may have the
same address), the
.Fl ifp
or
.Fl ifa
modifiers may be used to determine the interface or interface address.
.Pp
All symbolic names specified for a
.Ar destination
or 
.Ar gateway
are looked up first as a host name using
.Xr gethostbyname 3 .
If this lookup fails,
.Xr getnetbyname 3
is then used to interpret the name as that of a network.
.Pp
.Nm Route
uses a routing socket and the new message types
RTM_ADD,
RTM_DELETE,
RTM_GET,
and
RTM_CHANGE.
As such, only the super-user may modify
the routing tables.
.Pp
If the 
.Cm flush
command is specified, 
.Nm route
will ``flush'' the routing tables of all gateway entries.
One can choose to flush only those routes whose destinations
are of a given address family, by specifying an optional keyword
describing which address family.
.Sh DIAGNOSTICS
.Bl -tag -width Ds
.It Sy "add [host \&| network ] %s: gateway %s flags %x"
The specified route is being added to the tables.  The
values printed are from the routing table entry supplied
in the 
.Xr ioctl 2
call.
If the gateway address used was not the primary address of the gateway
(the first one returned by
.Xr gethostbyname 3 ) ,
the gateway address is printed numerically as well as symbolically.
.It Sy "delete [ host &| network ] %s: gateway %s flags %x" 
As above, but when deleting an entry.
.It Sy "%s %s done"
When the 
.Cm flush
command is specified, each routing table entry deleted
is indicated with a message of this form.
.It Sy "Network is unreachable"
An attempt to add a route failed because the gateway listed was not
on a directly-connected network.
The next-hop gateway must be given.
.It Sy "not in table"
A delete operation was attempted for an entry which
wasn't present in the tables.
.It Sy "routing table overflow"
An add operation was attempted, but the system was
low on resources and was unable to allocate memory
to create the new entry.
.El
.Sh SEE ALSO
.Xr netintro 4 ,
.Xr route 4 ,
.Xr esis 4 ,
.Xr routed 8 ,
.Xr XNSrouted 8
.Sh HISTORY
The
.Nm
command appeared in
.Bx 4.2 .
.Sh BUGS
The first paragraph may have slightly exaggerated
.Xr routed Ns 's
abilities.