diff options
Diffstat (limited to 'doc/nft.txt')
| -rw-r--r-- | doc/nft.txt | 58 |
1 files changed, 45 insertions, 13 deletions
diff --git a/doc/nft.txt b/doc/nft.txt index 83f0f8bb..e4eb982e 100644 --- a/doc/nft.txt +++ b/doc/nft.txt @@ -321,7 +321,7 @@ Effectively, this is the nft-equivalent of *iptables-save* and TABLES ------ [verse] -{*add* | *create*} *table* ['family'] 'table' [ {*comment* 'comment' *;*'} *{ flags* 'flags' *; }*] +{*add* | *create*} *table* ['family'] 'table' [*{* [*comment* 'comment' *;*] [*flags* 'flags' *;*] *}*] {*delete* | *destroy* | *list* | *flush*} *table* ['family'] 'table' *list tables* ['family'] *delete table* ['family'] *handle* 'handle' @@ -343,8 +343,17 @@ return an error. |Flag | Description |dormant | table is not evaluated any more (base chains are unregistered). +|owner | +table is owned by the creating process. +|persist | +table shall outlive the owning process. |================= +Creating a table with flag *owner* excludes other processes from manipulating +it or its contents. By default, it will be removed when the process exits. +Setting flag *persist* will prevent this and the resulting orphaned table will +accept a new owner, e.g. a restarting daemon maintaining the table. + .*Add, change, delete a table* --------------------------------------- # start nft in interactive mode @@ -376,7 +385,7 @@ add table inet mytable CHAINS ------ [verse] -{*add* | *create*} *chain* ['family'] 'table' 'chain' [*{ type* 'type' *hook* 'hook' [*device* 'device'] *priority* 'priority' *;* [*policy* 'policy' *;*] [*comment* 'comment' *;*'] *}*] +{*add* | *create*} *chain* ['family'] 'table' 'chain' [*{ type* 'type' *hook* 'hook' [*device* 'device'] *priority* 'priority' *;* [*policy* 'policy' *;*] [*comment* 'comment' *;*] *}*] {*delete* | *destroy* | *list* | *flush*} *chain* ['family'] 'table' 'chain' *list chains* ['family'] *delete chain* ['family'] 'table' *handle* 'handle' @@ -434,6 +443,11 @@ further quirks worth noticing: *prerouting*, *input*, *forward*, *output*, *postrouting* and this *ingress* hook. +The *device* parameter accepts a network interface name as a string, and is +required when adding a base chain that filters traffic on the ingress or +egress hooks. Any ingress or egress chains will only filter traffic from the +interface specified in the *device* parameter. + The *priority* parameter accepts a signed integer value or a standard priority name which specifies the order in which chains with the same *hook* value are traversed. The ordering is ascending, i.e. lower priority values have precedence @@ -519,7 +533,7 @@ beginning of the chain or before the specified rule. *replace*:: Similar to *add*, but the rule replaces the specified rule. *delete*:: Delete the specified rule. *destroy*:: Delete the specified rule, it does not fail if it does not exist. -*reset*:: Reset rule-contained state, i.e. counter and quota statement values. +*reset*:: Reset rule-contained state, e.g. counter and quota statement values. .*add a rule to ip table output chain* ------------- @@ -570,7 +584,7 @@ section describes nft set syntax in more detail. [verse] *add set* ['family'] 'table' 'set' *{ type* 'type' | *typeof* 'expression' *;* [*flags* 'flags' *;*] [*timeout* 'timeout' *;*] [*gc-interval* 'gc-interval' *;*] [*elements = {* 'element'[*,* ...] *} ;*] [*size* 'size' *;*] [*comment* 'comment' *;*'] [*policy* 'policy' *;*] [*auto-merge ;*] *}* -{*delete* | *destroy* | *list* | *flush*} *set* ['family'] 'table' 'set' +{*delete* | *destroy* | *list* | *flush* | *reset* } *set* ['family'] 'table' 'set' *list sets* ['family'] *delete set* ['family'] 'table' *handle* 'handle' {*add* | *delete* | *destroy* } *element* ['family'] 'table' 'set' *{* 'element'[*,* ...] *}* @@ -585,6 +599,7 @@ be tuned with the flags that can be specified at set creation time. *destroy*:: Delete the specified set, it does not fail if it does not exist. *list*:: Display the elements in the specified set. *flush*:: Remove all elements from the specified set. +*reset*:: Reset state in all contained elements, e.g. counter and quota statement values. .Set specifications [options="header"] @@ -597,8 +612,7 @@ string: ipv4_addr, ipv6_addr, ether_addr, inet_proto, inet_service, mark data type of set element | expression to derive the data type from |flags | -set flags | -string: constant, dynamic, interval, timeout +set flags | string: constant, dynamic, interval, timeout. Used to describe the sets properties. |timeout | time an element stays in the set, mandatory if set is added to from the packet path (ruleset)| string, decimal followed by unit. Units are: d, h, m, s @@ -624,7 +638,7 @@ MAPS ----- [verse] *add map* ['family'] 'table' 'map' *{ type* 'type' | *typeof* 'expression' [*flags* 'flags' *;*] [*elements = {* 'element'[*,* ...] *} ;*] [*size* 'size' *;*] [*comment* 'comment' *;*'] [*policy* 'policy' *;*] *}* -{*delete* | *destroy* | *list* | *flush*} *map* ['family'] 'table' 'map' +{*delete* | *destroy* | *list* | *flush* | *reset* } *map* ['family'] 'table' 'map' *list maps* ['family'] Maps store data based on some specific key used as input. They are uniquely identified by a user-defined name and attached to tables. @@ -635,8 +649,7 @@ Maps store data based on some specific key used as input. They are uniquely iden *destroy*:: Delete the specified map, it does not fail if it does not exist. *list*:: Display the elements in the specified map. *flush*:: Remove all elements from the specified map. -*add element*:: Comma-separated list of elements to add into the specified map. -*delete element*:: Comma-separated list of element keys to delete from the specified map. +*reset*:: Reset state in all contained elements, e.g. counter and quota statement values. .Map specifications [options="header"] @@ -650,7 +663,7 @@ data type of set element | expression to derive the data type from |flags | map flags | -string: constant, interval +string, same as set flags |elements | elements contained by the map | map data type @@ -662,12 +675,28 @@ map policy | string: performance [default], memory |================= +Users can specifiy the properties/features that the set/map must support. +This allows the kernel to pick an optimal internal representation. +If a required flag is missing, the ruleset might still work, as +nftables will auto-enable features if it can infer this from the ruleset. +This may not work for all cases, however, so it is recommended to +specify all required features in the set/map definition manually. + +.Set and Map flags +[options="header"] +|================= +|Flag | Description +|constant | Set contents will never change after creation +|dynamic | Set must support updates from the packet path with the *add*, *update* or *delete* keywords. +|interval | Set must be able to store intervals (ranges) +|timeout | Set must support element timeouts (auto-removal of elements once they expire). +|================= ELEMENTS -------- [verse] ____ -{*add* | *create* | *delete* | *destroy* | *get* } *element* ['family'] 'table' 'set' *{* 'ELEMENT'[*,* ...] *}* +{*add* | *create* | *delete* | *destroy* | *get* | *reset* } *element* ['family'] 'table' 'set' *{* 'ELEMENT'[*,* ...] *}* 'ELEMENT' := 'key_expression' 'OPTIONS' [*:* 'value_expression'] 'OPTIONS' := [*timeout* 'TIMESPEC'] [*expires* 'TIMESPEC'] [*comment* 'string'] @@ -687,6 +716,9 @@ listed elements may already exist. be non-trivial in very large and/or interval sets. In the latter case, the containing interval is returned instead of just the element itself. +*reset* command resets state attached to the given element(s), e.g. counter and +quota statement values. + .Element options [options="header"] |================= @@ -715,8 +747,8 @@ protocols. Each entry also caches the destination interface and the gateway address - to update the destination link-layer address - to forward packets. The ttl and hoplimit fields are also decremented. Hence, flowtables provides an alternative path that allow packets to bypass the classic forwarding path. -Flowtables reside in the ingress hook that is located before the prerouting -hook. You can select which flows you want to offload through the flow +Flowtables reside in the ingress *hook* that is located before the prerouting +*hook*. You can select which flows you want to offload through the flow expression from the forward chain. Flowtables are identified by their address family and their name. The address family must be one of ip, ip6, or inet. The inet address family is a dummy family which is used to create hybrid IPv4/IPv6 |