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diff --git a/man/man8/ip-rule.8 b/man/man8/ip-rule.8 new file mode 100644 index 0000000..d10b8b2 --- /dev/null +++ b/man/man8/ip-rule.8 @@ -0,0 +1,358 @@ +.TH IP\-RULE 8 "20 Dec 2011" "iproute2" "Linux" +.SH "NAME" +ip-rule \- routing policy database management +.SH "SYNOPSIS" +.sp +.ad l +.in +8 +.ti -8 +.B ip +.RI "[ " OPTIONS " ]" +.B rule +.RI "{ " COMMAND " | " +.BR help " }" +.sp + +.ti -8 +.B ip rule +.RB "[ " show +.RI "[ " SELECTOR " ]]" + +.ti -8 +.B ip rule +.RB "{ " add " | " del " }" +.I SELECTOR ACTION + +.ti -8 +.B ip rule +.RB "{ " flush " | " save " | " restore " }" + +.ti -8 +.IR SELECTOR " := [ " +.BR not " ] [" +.B from +.IR PREFIX " ] [ " +.B to +.IR PREFIX " ] [ " +.B tos +.IR TOS " ] [ " +.B fwmark +.IR FWMARK\fR[\fB/\fIMASK "] ] [ " +.B iif +.IR STRING " ] [ " +.B oif +.IR STRING " ] [ " +.B priority +.IR PREFERENCE " ] [ " +.IR l3mdev " ] [ " +.B uidrange +.IR NUMBER "-" NUMBER " ] [ " +.B ipproto +.IR PROTOCOL " ] [ " +.BR sport " [ " +.IR NUMBER " | " +.IR NUMBER "-" NUMBER " ] ] [ " +.BR dport " [ " +.IR NUMBER " | " +.IR NUMBER "-" NUMBER " ] ] [ " +.B tun_id +.IR TUN_ID " ]" +.BR + + +.ti -8 +.IR ACTION " := [ " +.B table +.IR TABLE_ID " ] [ " +.B protocol +.IR PROTO " ] [ " +.B nat +.IR ADDRESS " ] [ " +.B realms +.RI "[" SRCREALM "\fB/\fR]" DSTREALM " ] [" +.B goto +.IR NUMBER " ] " SUPPRESSOR + +.ti -8 +.IR SUPPRESSOR " := [ " +.B suppress_prefixlength +.IR NUMBER " ] [ " +.B suppress_ifgroup +.IR GROUP " ]" + +.ti -8 +.IR TABLE_ID " := [ " +.BR local " | " main " | " default " |" +.IR NUMBER " ]" + +.SH DESCRIPTION +.I ip rule +manipulates rules +in the routing policy database that controls the route selection algorithm. + +.P +Classic routing algorithms used in the Internet make routing decisions +based only on the destination address of packets (and in theory, +but not in practice, on the TOS field). + +.P +In some circumstances, we want to route packets differently depending not only +on destination addresses but also on other packet fields: source address, +IP protocol, transport protocol ports or even packet payload. +This task is called 'policy routing'. + +.P +To solve this task, the conventional destination based routing table, ordered +according to the longest match rule, is replaced with a 'routing policy +database' (or RPDB), which selects routes by executing some set of rules. + +.P +Each policy routing rule consists of a +.B selector +and an +.B action predicate. +The RPDB is scanned in order of decreasing priority (note that a lower number +means higher priority, see the description of +.I PREFERENCE +below). The selector +of each rule is applied to {source address, destination address, incoming +interface, tos, fwmark} and, if the selector matches the packet, +the action is performed. The action predicate may return with success. +In this case, it will either give a route or failure indication +and the RPDB lookup is terminated. Otherwise, the RPDB program +continues with the next rule. + +.P +Semantically, the natural action is to select the nexthop and the output device. + +.P +At startup time the kernel configures the default RPDB consisting of three +rules: + +.TP +1. +Priority: 0, Selector: match anything, Action: lookup routing +table +.B local +(ID 255). +The +.B local +table is a special routing table containing +high priority control routes for local and broadcast addresses. + +.TP +2. +Priority: 32766, Selector: match anything, Action: lookup routing +table +.B main +(ID 254). +The +.B main +table is the normal routing table containing all non-policy +routes. This rule may be deleted and/or overridden with other +ones by the administrator. + +.TP +3. +Priority: 32767, Selector: match anything, Action: lookup routing +table +.B default +(ID 253). +The +.B default +table is empty. It is reserved for some post-processing if no previous +default rules selected the packet. +This rule may also be deleted. + +.P +Each RPDB entry has additional +attributes. F.e. each rule has a pointer to some routing +table. NAT and masquerading rules have an attribute to select new IP +address to translate/masquerade. Besides that, rules have some +optional attributes, which routes have, namely +.BR "realms" . +These values do not override those contained in the routing tables. They +are only used if the route did not select any attributes. + +.sp +The RPDB may contain rules of the following types: + +.RS +.B unicast +- the rule returns the route found +in the routing table referenced by the rule. + +.B blackhole +- the rule causes a silent drop the packet. + +.B unreachable +- the rule generates a 'Network is unreachable' error. + +.B prohibit +- the rule generates 'Communication is administratively +prohibited' error. + +.B nat +- the rule translates the source address +of the IP packet into some other value. +.RE + +.TP +.B ip rule add - insert a new rule +.TP +.B ip rule delete - delete a rule +.RS +.TP +.BI type " TYPE " (default) +the type of this rule. The list of valid types was given in the previous +subsection. + +.TP +.BI from " PREFIX" +select the source prefix to match. + +.TP +.BI to " PREFIX" +select the destination prefix to match. + +.TP +.BI iif " NAME" +select the incoming device to match. If the interface is loopback, +the rule only matches packets originating from this host. This means +that you may create separate routing tables for forwarded and local +packets and, hence, completely segregate them. + +.TP +.BI oif " NAME" +select the outgoing device to match. The outgoing interface is only +available for packets originating from local sockets that are bound to +a device. + +.TP +.BI tos " TOS" +.TP +.BI dsfield " TOS" +select the TOS value to match. + +.TP +.BI fwmark " MARK" +select the +.B fwmark +value to match. + +.TP +.BI uidrange " NUMBER-NUMBER" +select the +.B uid +value to match. + +.TP +.BI ipproto " PROTOCOL" +select the ip protocol value to match. + +.TP +.BI sport " NUMBER | NUMBER-NUMBER" +select the source port value to match. supports port range. + +.TP +.BI dport " NUMBER | NUMBER-NUMBER" +select the destination port value to match. supports port range. + +.TP +.BI priority " PREFERENCE" +the priority of this rule. +.I PREFERENCE +is an unsigned integer value, higher number means lower priority, and rules get +processed in order of increasing number. Each rule +should have an explicitly set +.I unique +priority value. +The options preference and order are synonyms with priority. + +.TP +.BI table " TABLEID" +the routing table identifier to lookup if the rule selector matches. +It is also possible to use lookup instead of table. + +.TP +.BI protocol " PROTO" +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. + +.TP +.BI suppress_prefixlength " NUMBER" +reject routing decisions that have a prefix length of NUMBER or less. + +.TP +.BI suppress_ifgroup " GROUP" +reject routing decisions that use a device belonging to the interface +group GROUP. + +.TP +.BI realms " FROM/TO" +Realms to select if the rule matched and the routing table lookup +succeeded. Realm +.I TO +is only used if the route did not select any realm. + +.TP +.BI nat " ADDRESS" +The base of the IP address block to translate (for source addresses). +The +.I ADDRESS +may be either the start of the block of NAT addresses (selected by NAT +routes) or a local host address (or even zero). +In the last case the router does not translate the packets, but +masquerades them to this address. +Using map-to instead of nat means the same thing. + +.B Warning: +Changes to the RPDB made with these commands do not become active +immediately. It is assumed that after a script finishes a batch of +updates, it flushes the routing cache with +.BR "ip route flush cache" . +.RE +.TP +.B ip rule flush - also dumps all the deleted rules. +.RS +.TP +.BI protocol " PROTO" +Select the originating protocol. +.RE +.TP +.B ip rule show - list rules +This command has no arguments. +The options list or lst are synonyms with show. + +.TP +.B ip rule save +.RS +.TP +.BI protocol " PROTO" +Select the originating protocol. +.RE +.TP +save rules table information to stdout +.RS +This command behaves like +.BR "ip rule show" +except that the output is raw data suitable for passing to +.BR "ip rule restore" . +.RE + +.TP +.B ip rule restore +restore rules table information from stdin +.RS +This command expects to read a data stream as returned from +.BR "ip rule save" . +It will attempt to restore the rules table information exactly as +it was at the time of the save. Any rules already in the table are +left unchanged, and duplicates are not ignored. +.RE + +.SH SEE ALSO +.br +.BR ip (8) + +.SH AUTHOR +Original Manpage by Michail Litvak <mci@owl.openwall.com> |