 @@ -1,469 +1,469 @@
-.\"	$NetBSD: route.8,v 1.62 2020/08/29 19:27:08 christos Exp $
+.\"	$NetBSD: route.8,v 1.63 2021/01/02 19:50:42 uwe Exp $
 .\"
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 .\"     @(#)route.8	8.4 (Berkeley) 6/1/94
 .\"
 .Dd August 29, 2020
 .Dt ROUTE 8
 .Os
 .Sh NAME
 .Nm route
 .Nd manually manipulate the routing tables
 .Sh SYNOPSIS
 .Nm
 .Op Fl dfLnqSsTtv
 .Ar command
 .Oo
 .Op Ar modifiers
 .Ar args
 .Oc
 .Sh DESCRIPTION
 .Nm
 is a utility used to manually manipulate the network
 routing tables.
 Except for setting up the default route, it is normally not needed,
 as a system routing table management daemon such as
 .Xr routed 8 ,
 should tend to this task.
 .Pp
 .Nm
 can be used to modify nearly any aspect of the routing policy,
 except packet forwarding, which can be manipulated through the
 .Xr sysctl 8
 command.
 .Pp
 The
 .Nm
 utility supports a limited number of general options,
 but a rich command language, enabling the user to specify
 any arbitrary request that could be delivered via the
 programmatic interface discussed in
 .Xr route 4 .
 .Bl -tag -width Ds
 .It Fl d
 Turn on debugging
 .It Fl f
 Remove all routes (as per
 .Cm flush ) .
 If used in conjunction with the
 .Cm add ,
 .Cm change ,
 .Cm delete
 or
 .Cm get
 commands,
 .Nm
 removes the routes before performing the command.
 .It Fl L
 Don't show link layer entries in routing table.
 .It Fl n
 Bypasses attempts to print host and network names symbolically
 when reporting actions.
 (The process of translating between symbolic
 names and numerical equivalents can be quite time consuming, and
 may require correct operation of the network; thus it may be expedient
 to forgo this, especially when attempting to repair networking operations).
 .It Fl q
 Suppress all output from commands that manipulate the routing table.
 .It Fl S
 Print a space when a flag is missing so that flags are vertically aligned
 instead of printing the flags that are set as a contiguous string.
 .It Fl s
 (short) Suppresses all output from a
 .Cm get
 command except for the actual gateway that will be used.
 How the gateway is printed depends on the type of route being looked up.
 .It Fl T
 Show tags in the route display.
 .It Fl t
 Test only, don't perform any actions.
 .It Fl v
 (verbose) Print additional details.
 .El
 .Pp
 The
 .Nm
 utility provides several commands:
 .Pp
 .Bl -tag -width Fl -compact
 .It Cm add
 Add a route.
 .It Cm flush
 Remove all routes.
 .It Cm flushall
 Remove all routes including the default gateway.
 .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 show
 Print out the route table similar to "netstat \-r" (see
 .Xr netstat 1 ) .
 .It Cm monitor
 Continuously report any changes to the routing information base,
 routing lookup misses, or suspected network partitionings.
 .El
 .Pp
 The monitor command has the syntax
 .Pp
 .Bd -filled -offset indent -compact
 .Nm
 .Op Fl n
 .Cm monitor
 .Op Fl c Ar count
 .Ed
 .Pp
 If
 .Ar count
 is specified,
 .Nm
 exits after receiving
 .Ar count
 routing messages.
 .Pp
 The flush command has the syntax
 .Pp
 .Bd -filled -offset indent -compact
 .Nm
 .Op Fl n
 .Cm flush
 .Op Ar family
 .Ed
 .Pp
 If the
 .Cm flush
 command is specified,
 .Nm
 will ``flush'' the routing tables of all gateway entries.
 When the address family is specified by any of the
 .Fl atalk ,
 .Fl inet ,
 .Fl inet6 ,
 or
 .Fl mpls
 modifiers, only routes having destinations with addresses in the
 delineated family will be manipulated.
 .Pp
 The other commands have the following syntax:
 .Pp
 .Bd -filled -offset indent -compact
 .Nm
 .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, and
 .Ar gateway
 is the next-hop intermediary via which packets should be routed.
 Routes to a particular host may be distinguished from those to
 a network by interpreting the Internet address specified as the
 .Ar destination
 argument.
 The optional modifiers
 .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
 .Dv 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.
 Optionally, the
 .Ar destination
 can also be specified in the
 .Ar net Ns / Ns Ar bits
 format.
 .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
 The keyword
 .Cm default
 can be used as the
 .Ar destination
 to set up a default route to a smart
 .Ar gateway .
 If no other routes match, this default route will be used as a last resort.
 .Pp
 If the destination is directly reachable
 via an interface requiring
 no intermediary system to act as 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 atalk ,
 and
 .Fl link
 specify that all subsequent addresses are in the
 .Tn AppleTalk
 address family,
 or are specified as link-level addresses in the form described in
 .Xr link_addr 3 ,
 and the names must be numeric specifications rather than
 symbolic names.
 .Pp
 The optional modifier
 .Fl tag
 specifies an address associated with the route.
 How the address is used is specific to the address family of
 the destination and the interface used to forward the packet.
 Currently route tags are consumed only by the
 .Xr mpls 4
 stack; therefore
 .Nm
 assumes that the subsequent addresses are in the
 .Tn MPLS
 address family.
 See
 .Xr mpls 4
 for examples of setting routes involving MPLS.
 .Pp
 The optional
 .Fl netmask
 qualifier is intended
 to achieve the effect of an
 .Tn ESIS
 redirect with the netmask option,
 or to manually add subnet routes with
 netmasks different from that of the implied network interface
 (as would otherwise be communicated using the OSPF or ISIS routing protocols).
 One specifies an additional ensuing address parameter
 (to be interpreted as a network mask).
 The implicit network mask generated in the
 .Dv AF_INET
 case
 can be overridden by making sure this option follows the destination parameter.
 .Fl prefixlen
 is also available for similar purpose, in IPv4 and IPv6 case.
 .Pp
 Routes have associated flags which influence operation of the protocols
 when sending to destinations matched by the routes.
 These flags are displayed using the following ID characters in the routing
 display and may be set (or sometimes cleared)
 by indicating the following corresponding modifiers:
 .Bl -column "ID" "xnoblackhole" "xRTF_BLACKHOLE" "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
 .It Sy "ID" Ta Sy "Modifier" Ta Sy " Flag Bit" Ta Sy "Description"
 .It Li " " Ta -iface Ta ~RTF_GATEWAY Ta destination is directly reachable
 .It Li 1 Ta -proto1 Ta " RTF_PROTO1" Ta set protocol specific flag #1
 .It Li 2 Ta -proto2 Ta " RTF_PROTO2" Ta set protocol specific flag #2
 .It Li B Ta -blackhole Ta " RTF_BLACKHOLE" Ta discard pkts (during updates)
 .It Li b Ta "" Ta " RTF_BROADCAST" Ta Route represents a broadcast address
 .It Li " " Ta -noblackhole Ta ~RTF_BLACKHOLE Ta clear blackhole flag
 .It Li b Ta "" Ta " RTF_BROADCAST" Ta Route represents a broadcast address
 .It Li C Ta -cloning Ta " RTF_CLONING" Ta  (deprecated) same as
 .Fl connected
 .It Li " " Ta -nocloning Ta ~RTF_CLONING Ta (deprecated) same as
 .Fl noconnected
 .It Li C Ta -connected Ta " RTF_CONNECTED" Ta  treat as a connected route
 .It Li " " Ta -noconnected Ta ~RTF_CONNECTED Ta stop treating a connected route
 .It Li D Ta "" Ta " RTF_DYNAMIC" Ta created dynamically (redirect)
 .It Li G Ta "" Ta " RTF_GATEWAY" Ta forwarded to dest by intermediary
 .It Li H Ta "" Ta " RTF_HOST" Ta host entry (net otherwise)
 .It Li L Ta "" Ta " RTF_LLDATA" Ta local link, generated by ARP or NDP
 .It Li l Ta "" Ta " RTF_LOCAL" Ta Route represents a local address
 .It Li M Ta "" Ta " RTF_MODIFIED" Ta modified dynamically (redirect)
 .It Li p Ta -proxy Ta " RTF_ANNOUNCE" Ta make entry a link level proxy
 .It Li R Ta -reject Ta " RTF_REJECT" Ta send ICMP unreachable on match
 .It Li " " Ta -noreject Ta ~RTF_REJECT Ta clear reject flag
 .It Li S Ta -static Ta " RTF_STATIC" Ta manually added route
 .It Li " " Ta -nostatic Ta ~RTF_STATIC Ta pretend route added automatically
 .It Li U Ta "" Ta " RTF_UP" Ta route usable
 .El
 .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 quantities maintained in the routing entry
 by transport level protocols, such as TCP or TP4.
 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 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
 uses a routing socket and the new message types
 .Dv RTM_ADD ,
 .Dv RTM_DELETE ,
 .Dv RTM_GET ,
 and
 .Dv RTM_CHANGE .
 As such, only the super-user may modify
 the routing tables.
 .Sh EXIT STATUS
 .Ex -std route
 This includes the use of the
 .Cm get
 command to look up a route that is incomplete.
 .Sh EXAMPLES
 This sets the default route to 192.168.0.1:
 .Dl route add default 192.168.0.1
 This shows all routes, without DNS resolution (this is useful if the
 DNS is not available):
 .Dl route -n show
 To install a static route through 10.200.0.1 to reach the network
 .168.1.0/28, use this:
 .Dl route add -net 192.168.1.0 -netmask 255.255.255.240 10.200.0.1
 .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.
 .It Sy "Permission denied"
 The attempted operation is privileged.
 Only root may modify the routing tables.
 These privileges are enforced by the kernel.
 .El
 .Sh SEE ALSO
 .Xr mpls 4 ,
 .Xr netintro 4 ,
 .Xr route 4 ,
 .Xr routed 8 ,
 .Xr sysctl 8
 .Sh HISTORY
 The
 .Nm
 command appeared in
 .Bx 4.2 .
 IPv6 support was added by WIDE/KAME project.
 .Pp
 Since
 .Nx 8.0 ,
 .Fl cloned ,
 .Fl nocloned ,
 .Fl llinfo
 and
 .Fl xresolve
 were obsolete and
 .Fl cloning
 and
 .Fl nocloning
 were deprecated.
 .Fl connected
 and
 .Fl noconnected
 appeared in
 .Nx 8.0 .
 .Sh BUGS
 The first paragraph may have slightly exaggerated
 .Xr routed 8 Ns 's
 abilities.
 .Pp
 Some uses of the
 .Fl ifa
 or
 .Fl ifp
 modifiers with the add command will incorrectly fail with a
 .Dq Network is unreachable
 message if there is no default route.
 See case
 .Dv RTM_ADD
 in
 .Pa sys/net/rtsock.c:route_output
 for details.