df6ec985f1
Add DSCP mask support, allowing users to specify a DSCP value with an
optional mask. Example:
# ip rule add dscp 1 table 100
# ip rule add dscp 0x02/0x3f table 200
# ip rule add dscp AF42/0x3f table 300
# ip rule add dscp 0x10/0x30 table 400
In non-JSON output, the DSCP mask is not printed in case of exact match
and the DSCP value is printed in hexadecimal format in case of inexact
match:
$ ip rule show
0: from all lookup local
32762: from all lookup 400 dscp 0x10/0x30
32763: from all lookup 300 dscp AF42
32764: from all lookup 200 dscp 2
32765: from all lookup 100 dscp 1
32766: from all lookup main
32767: from all lookup default
Dump can be filtered by DSCP value and mask:
$ ip rule show dscp 1
32765: from all lookup 100 dscp 1
$ ip rule show dscp AF42
32763: from all lookup 300 dscp AF42
$ ip rule show dscp 0x10/0x30
32762: from all lookup 400 dscp 0x10/0x30
In JSON output, the DSCP mask is printed as an hexadecimal string to be
consistent with other masks. The DSCP value is printed as an integer in
order not to break existing scripts:
$ ip -j -p -N rule show dscp 0x10/0x30
[ {
"priority": 32762,
"src": "all",
"table": "400",
"dscp": "16",
"dscp_mask": "0x30"
} ]
The mask attribute is only sent to the kernel in case of inexact match
so that iproute2 will continue working with kernels that do not support
the attribute.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David Ahern <dsahern@kernel.org>
385 lines
9.0 KiB
Groff
385 lines
9.0 KiB
Groff
.TH IP\-RULE 8 "20 Dec 2011" "iproute2" "Linux"
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.SH "NAME"
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ip-rule \- routing policy database management
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.SH "SYNOPSIS"
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.sp
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.ad l
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.in +8
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.ti -8
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.B ip
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.RI "[ " OPTIONS " ]"
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.B rule
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.RI "{ " COMMAND " | "
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.BR help " }"
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.sp
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.ti -8
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.B ip rule
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.RB "[ " show
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.RI "[ " SELECTOR " ]]"
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.ti -8
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.B ip rule
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.RB "{ " add " | " del " }"
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.I SELECTOR ACTION
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.ti -8
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.B ip rule
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.RB "{ " flush " | " save " | " restore " }"
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.ti -8
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.IR SELECTOR " := [ "
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.BR not " ] ["
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.B from
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.IR PREFIX " ] [ "
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.B to
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.IR PREFIX " ] [ "
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.B tos
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.IR TOS " ] [ "
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.B dscp
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.IR DSCP\fR[\fB/\fIMASK "] ] [ "
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.B fwmark
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.IR FWMARK\fR[\fB/\fIMASK "] ] [ "
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.B iif
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.IR STRING " ] [ "
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.B oif
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.IR STRING " ] [ "
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.B priority
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.IR PREFERENCE " ] [ "
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.IR l3mdev " ] [ "
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.B uidrange
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.IR NUMBER "-" NUMBER " ] [ "
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.B ipproto
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.IR PROTOCOL " ] [ "
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.BR sport " [ "
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.IR NUMBER\fR[\fB/\fIMASK "] | "
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.IR NUMBER "-" NUMBER " ] ] [ "
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.BR dport " [ "
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.IR NUMBER\fR[\fB/\fIMASK "] | "
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.IR NUMBER "-" NUMBER " ] ] [ "
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.B tun_id
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.IR TUN_ID " ] [ "
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.B flowlabel
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.IR FLOWLABEL\fR[\fB/\fIMASK "] ]"
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.BR
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.ti -8
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.IR ACTION " := [ "
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.B table
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.IR TABLE_ID " ] [ "
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.B protocol
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.IR PROTO " ] [ "
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.B nat
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.IR ADDRESS " ] [ "
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.B realms
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.RI "[" SRCREALM "\fB/\fR]" DSTREALM " ] ["
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.B goto
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.IR NUMBER " ] " SUPPRESSOR
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.ti -8
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.IR SUPPRESSOR " := [ "
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.B suppress_prefixlength
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.IR NUMBER " ] [ "
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.B suppress_ifgroup
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.IR GROUP " ]"
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.ti -8
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.IR TABLE_ID " := [ "
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.BR local " | " main " | " default " |"
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.IR NUMBER " ]"
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.SH DESCRIPTION
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.I ip rule
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manipulates rules
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in the routing policy database that controls the route selection algorithm.
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.P
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Classic routing algorithms used in the Internet make routing decisions
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based only on the destination address of packets (and in theory,
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but not in practice, on the TOS field).
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.P
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In some circumstances, we want to route packets differently depending not only
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on destination addresses but also on other packet fields: source address,
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IP protocol, transport protocol ports or even packet payload.
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This task is called 'policy routing'.
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.P
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To solve this task, the conventional destination based routing table, ordered
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according to the longest match rule, is replaced with a 'routing policy
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database' (or RPDB), which selects routes by executing some set of rules.
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.P
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Each policy routing rule consists of a
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.B selector
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and an
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.B action predicate.
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The RPDB is scanned in order of decreasing priority (note that a lower number
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means higher priority, see the description of
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.I PREFERENCE
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below). The selector
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of each rule is applied to {source address, destination address, incoming
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interface, tos, fwmark} and, if the selector matches the packet,
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the action is performed. The action predicate may return with success.
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In this case, it will either give a route or failure indication
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and the RPDB lookup is terminated. Otherwise, the RPDB program
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continues with the next rule.
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.P
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Semantically, the natural action is to select the nexthop and the output device.
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.P
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At startup time the kernel configures the default RPDB consisting of three
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rules:
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.TP
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1.
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Priority: 0, Selector: match anything, Action: lookup routing
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table
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.B local
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(ID 255).
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The
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.B local
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table is a special routing table containing
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high priority control routes for local and broadcast addresses.
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.TP
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2.
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Priority: 32766, Selector: match anything, Action: lookup routing
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table
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.B main
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(ID 254).
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The
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.B main
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table is the normal routing table containing all non-policy
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routes. This rule may be deleted and/or overridden with other
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ones by the administrator.
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.TP
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3.
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Priority: 32767, Selector: match anything, Action: lookup routing
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table
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.B default
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(ID 253).
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The
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.B default
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table is empty. It is reserved for some post-processing if no previous
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default rules selected the packet.
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This rule may also be deleted.
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.P
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Each RPDB entry has additional
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attributes. F.e. each rule has a pointer to some routing
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table. NAT and masquerading rules have an attribute to select new IP
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address to translate/masquerade. Besides that, rules have some
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optional attributes, which routes have, namely
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.BR "realms" .
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These values do not override those contained in the routing tables. They
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are only used if the route did not select any attributes.
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.sp
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The RPDB may contain rules of the following types:
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.RS
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.B unicast
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- the rule returns the route found
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in the routing table referenced by the rule.
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.B blackhole
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- the rule causes a silent drop the packet.
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.B unreachable
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- the rule generates a 'Network is unreachable' error.
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.B prohibit
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- the rule generates 'Communication is administratively
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prohibited' error.
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.B nat
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- the rule translates the source address
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of the IP packet into some other value.
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.RE
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.TP
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.B ip rule add - insert a new rule
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.TP
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.B ip rule delete - delete a rule
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.RS
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.TP
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.BI type " TYPE " (default)
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the type of this rule. The list of valid types was given in the previous
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subsection.
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.TP
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.BI from " PREFIX"
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select the source prefix to match.
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.TP
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.BI to " PREFIX"
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select the destination prefix to match.
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.TP
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.BI iif " NAME"
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select the incoming device to match. If the interface is loopback,
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the rule only matches packets originating from this host. This means
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that you may create separate routing tables for forwarded and local
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packets and, hence, completely separate them.
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.TP
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.BI oif " NAME"
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select the outgoing device to match. The outgoing interface is only
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available for packets originating from local sockets that are bound to
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a device.
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.TP
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.BI tos " TOS"
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.TP
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.BI dsfield " TOS"
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select the TOS value to match.
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.TP
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.BI dscp " DSCP\fR[\fB/\fIMASK\fR]"
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select the DSCP value to match with an optional mask. DSCP values can be
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written either directly as numeric values (valid values are 0-63), or using
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symbolic names specified in
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.BR @SYSCONF_USR_DIR@/rt_dsfield " or " @SYSCONF_ETC_DIR@/rt_dsfield
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(has precedence if exists).
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However, note that the file specifies full 8-bit dsfield values, whereas
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.B ip rule
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will only use the higher six bits.
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.B ip rule show
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will similarly format DSCP values as symbolic names if possible. The
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command line option
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.B -N
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turns the show translation off.
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.TP
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.BI fwmark " MARK"
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select the
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.B fwmark
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value to match.
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.TP
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.BI uidrange " NUMBER-NUMBER"
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select the
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.B uid
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value to match.
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.TP
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.BI ipproto " PROTOCOL"
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select the ip protocol value to match.
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.TP
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.BI sport " NUMBER\fR[\fB/\fIMASK\fR] | NUMBER-NUMBER"
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select the source port value to match with an optional mask. Supports port
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range.
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.TP
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.BI dport " NUMBER\fR[\fB/\fIMASK\fR] | NUMBER-NUMBER"
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select the destination port value to match with an optional mask. Supports port
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range.
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.TP
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.BI priority " PREFERENCE"
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the priority of this rule.
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.I PREFERENCE
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is an unsigned integer value, higher number means lower priority, and rules get
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processed in order of increasing number. Each rule
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should have an explicitly set
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.I unique
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priority value.
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The options preference and order are synonyms with priority.
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.TP
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.BI table " TABLEID"
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the routing table identifier to lookup if the rule selector matches.
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It is also possible to use lookup instead of table.
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.TP
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.BI protocol " PROTO"
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the routing protocol who installed the rule in question. As an example when zebra installs a rule it would get RTPROT_ZEBRA as the installing protocol.
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.TP
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.BI suppress_prefixlength " NUMBER"
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reject routing decisions that have a prefix length of NUMBER or less.
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.TP
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.BI suppress_ifgroup " GROUP"
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reject routing decisions that use a device belonging to the interface
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group GROUP.
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.TP
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.BI realms " FROM/TO"
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Realms to select if the rule matched and the routing table lookup
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succeeded. Realm
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.I TO
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is only used if the route did not select any realm.
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.TP
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.BI nat " ADDRESS"
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The base of the IP address block to translate (for source addresses).
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The
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.I ADDRESS
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may be either the start of the block of NAT addresses (selected by NAT
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routes) or a local host address (or even zero).
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In the last case the router does not translate the packets, but
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masquerades them to this address.
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Using map-to instead of nat means the same thing.
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.TP
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.BI flowlabel " FLOWLABEL\fR[\fB/\fIMASK\fR]"
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select the IPv6 flow label to match with an optional mask.
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.B Warning:
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Changes to the RPDB made with these commands do not become active
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immediately. It is assumed that after a script finishes a batch of
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updates, it flushes the routing cache with
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.BR "ip route flush cache" .
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.RE
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.TP
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.B ip rule flush - also dumps all the deleted rules.
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.RS
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.TP
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.BI protocol " PROTO"
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Select the originating protocol.
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.RE
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.TP
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.B ip rule show - list rules
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This command has no arguments.
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The options list or lst are synonyms with show.
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.TP
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.B ip rule save
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.RS
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.TP
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.BI protocol " PROTO"
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Select the originating protocol.
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.RE
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.TP
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save rules table information to stdout
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.RS
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This command behaves like
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.BR "ip rule show"
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except that the output is raw data suitable for passing to
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.BR "ip rule restore" .
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.RE
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.TP
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.B ip rule restore
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restore rules table information from stdin
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.RS
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This command expects to read a data stream as returned from
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.BR "ip rule save" .
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It will attempt to restore the rules table information exactly as
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it was at the time of the save. Any rules already in the table are
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left unchanged, and duplicates are not ignored.
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.RE
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.SH SEE ALSO
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.br
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.BR ip (8)
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.SH AUTHOR
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Original Manpage by Michail Litvak <mci@owl.openwall.com>
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