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bfcli

bfcli is a command line tool to communicate with the bpfilter daemon. It provides supports for extended features compared to the iptables client.

Commands

bfcli commands are structured as bfcli OBJECT ACTION. The commands and actions supported by bfcli are described below.

ruleset set

Define a new ruleset: replace all the existing chains with the ruleset provided. Replacement is not atomic.

Chains with valid hook options defined are attached to their hook. Chains without hook options are only loaded into the kernel.

Options
  • --from-str RULESET: read and apply the ruleset defining from the command line.
  • --from-file FILE: read FILE and apply the ruleset contained in it.
  • --dry-run: parse and validate the ruleset, but do not apply it.

--from-str and --from-file are mutually exclusive.

Example

bfcli ruleset set --from-file myruleset.txt
bfcli ruleset set --from-str "chain my_xdp_chain BF_HOOK_XDP ACCEPT rule (ip4.saddr) in {192.168.1.1} ACCEPT"

ruleset get

Print the ruleset: request all the chains and rules from the daemon with counters values.

Example

$ sudo bfcli ruleset get
  chain my_tc_chain BF_HOOK_TC_INGRESS{ifindex=2} ACCEPT
      counters policy 87 packets 9085 bytes; error 0 packets 0 bytes
      rule
          ip4.saddr eq 0xc0 0xa8 0x01 0x01 0xff 0xff 0xff 0xff
          counters 2 packets 196 bytes
          ACCEPT

ruleset flush

Remove all the chains and rules defined by the daemon. Once this command completes, the daemon doesn't contain any filtering rules, as if it was freshly started.

Examples

$ sudo bfcli ruleset get
  chain my_tc_chain BF_HOOK_TC_INGRESS{ifindex=2} ACCEPT
      counters policy 87 packets 9085 bytes; error 0 packets 0 bytes
      rule
          ip4.saddr eq 0xc0 0xa8 0x01 0x01 0xff 0xff 0xff 0xff
          counters 2 packets 196 bytes
          ACCEPT
$ sudo bfcli ruleset flush
$ sudo bfcli ruleset get
$ # Empty ruleset

chain set

Generate and load a chain into the kernel. If the chain definition contains hook options, the daemon will attach it to its hook. Any existing chain with the same name (attached or not) will be discarded and replaced with the new one.

If you want to update an existing chain without downtime, use bfcli chain update instead.

Options
  • --from-str CHAIN: read the chain to set from the command line arguments.
  • --from-file FILEPATH: read the chain from a file.
  • --name NAME: if --from-str or --from-file provide multiple chains, NAME specify which one to send to the daemon.
  • --dry-run: parse and validate the chain, but do not apply it.

Examples

$ # Create an empty XDP chain, do not attach it
$ sudo bfcli chain set --from-str "chain my_xdp_chain BF_HOOK_XDP ACCEPT"
$ sudo bfcli chain get --name my_xdp_chain
  chain my_xdp_chain BF_HOOK_XDP ACCEPT
      counters policy 0 packets 0 bytes; error 0 packets 0 bytes

# Create an empty TC chain and attach it
$ sudo bfcli chain set --from-str "chain my_tc_chain BF_HOOK_TC_INGRESS{ifindex=2} ACCEPT"
$ sudo bfcli chain get --name my_tc_chain
  chain my_tc_chain BF_HOOK_TC_INGRESS{ifindex=2} ACCEPT
      counters policy 35 packets 4091 bytes; error 0 packets 0 bytes

chain get

Print a chain.

Options
  • --name NAME: name of the chain to print.

Examples

$ # Create a Netfilter chain and print it
$ sudo bfcli chain set --from-str "chain my_input_chain BF_HOOK_NF_LOCAL_IN{priorities=101-102} ACCEPT"
$ sudo bfcli chain get --name my_input_chain
  chain my_input_chain BF_HOOK_NF_LOCAL_IN{priorities=101-102} ACCEPT
      counters policy 1161 packets 149423 bytes; error 0 packets 0 bytes

chain logs

Print a chain's logged packets.

bfcli will print the logged headers as they are published by the chain. Only the headers requested in the log action will be printed. Hit Ctrl+C to quit.

For each logged packet, bfcli will print the receive timestamp and the packet size, followed by each requested layer (see the log action below). If one of the requested layer could not be processed by the chain, the corresponding output will be truncated.

Options
  • --name NAME: name of the chain to print the logged packets for.

Examples

$ # Create an XDP chain with logs and print the logs
$ sudo bfcli chain set --from-str "
  chain my_input_chain BF_HOOK_XDP{ifindex=2} ACCEPT
      rule
          meta.l4_proto tcp
          log transport
          CONTINUE
  "
$ sudo bfcli chain logs --name my_input_chain
  [15:14:32.652085] Packet: 66 bytes
    TCP       : 52719 → 22    [ack]
                seq=1643155516 ack=1290470623 win=4618

  [15:14:32.652842] Packet: 66 bytes
    TCP       : 52719 → 22    [ack]
                seq=1643155516 ack=1290470723 win=4619

  [...]

chain load

Generate and load a chain into the kernel. Hook options are ignored.

If a chain with the same name already exist, it won't be replaced. See bfcli chain set or bfcli chain update to replace an existing chain.

Options
  • --from-str CHAIN: read the chain to set from the command line arguments.
  • --from-file FILEPATH: read the chain from a file.
  • --name NAME: if --from-str or --from-file provide multiple chains, NAME specify which one to send to the daemon.
  • --dry-run: parse and validate the chain, but do not apply it.

Examples

$ # Create an XDP chain and print it
$ sudo bfcli chain load --from-str "chain my_xdp_chain BF_HOOK_XDP ACCEPT"
$ sudo bfcli chain get --name my_xdp_chain
  chain my_xdp_chain BF_HOOK_XDP ACCEPT
      counters policy 0 packets 0 bytes; error 0 packets 0 bytes

$ # Create a single chain from a string containing 2 chains. Hook options are ignored.
$ sudo bfcli chain load --name my_other_xdp_chain --from-str "
    chain my_next_xdp_chain BF_HOOK_XDP DROP
    chain my_other_xdp_chain BF_HOOK_XDP ACCEPT"
$ sudo bfcli chain get --name my_other_xdp_chain
  chain my_other_xdp_chain BF_HOOK_XDP ACCEPT
      counters policy 0 packets 0 bytes; error 0 packets 0 bytes

chain attach

Attach a loaded chain to its hook.

Only loaded chains (not attached) can be attached. See bfcli chain set and bfcli chain update if you want to update an existing chain.

See below for a list of available hook options.

Options
  • --name NAME: name of the chain to attach.
  • --option OPTION: hook-specific options to attach the chain to its hook. See hook options below.

Examples

$ # Load and attach an XDP chain, print it
$ sudo bfcli chain load --from-str "chain my_xdp_chain BF_HOOK_XDP ACCEPT"
$ sudo bfcli chain attach --name my_xdp_chain --option ifindex=2
$ sudo bfcli chain get --name my_xdp_chain
  chain my_xdp_chain BF_HOOK_XDP{ifindex=2} ACCEPT
      counters policy 101 packets 11714 bytes; error 0 packets 0 bytes

chain update

Update an existing chain. The new chain will atomically update the existing one. Hook options are ignored. The new chain will replace the existing chain with the same name. Counters are reset to zero.

If you want to modify the hook options, use bfcli chain set instead.

Options
  • --from-str CHAIN: read the chain to set from the command line arguments.
  • --from-file FILEPATH: read the chain from a file.
  • --name NAME: if --from-str or --from-file provide multiple chains, NAME specify which one to send to the daemon.
  • --dry-run: parse and validate the chain, but do not apply it.

Examples

$ # Set an XDP chain and update it
$ sudo bfcli chain set --from-str "chain my_xdp_chain BF_HOOK_XDP{ifindex=2} ACCEPT"
$ sudo bfcli chain get --name my_xdp_chain
  chain my_xdp_chain BF_HOOK_XDP{ifindex=2} ACCEPT
      counters policy 307 packets 36544 bytes; error 0 packets 0 bytes
$ sudo bfcli chain update --from-str "
      chain my_xdp_chain BF_HOOK_XDP{ifindex=2} ACCEPT
          rule
              ip4.proto eq icmp
              counter
              DROP"
$ sudo bfcli chain get --name my_xdp_chain
  chain my_xdp_chain BF_HOOK_XDP{ifindex=2} ACCEPT
      counters policy 204 packets 24074 bytes; error 0 packets 0 bytes
      rule
          ip4.proto eq 0x01
          counters 0 packets 0 bytes
          DROP

chain update-set

Atomically update the content of a named set in a chain using delta operations. This is more efficient than replacing the entire chain when you only need to modify set membership. Counters are preserved across the update.

Options
  • --name NAME: name of the chain containing the set.
  • --set-name NAME: name of the set to update.
  • --add ELEMENT: element to add to the set. Can be specified multiple times.
  • --remove ELEMENT: element to remove from the set. Can be specified multiple times.

At least one of --add or --remove must be specified.

Examples

$ # Create a chain with a named set
$ sudo bfcli chain set --from-str "
      chain my_filter BF_HOOK_XDP{ifindex=2} ACCEPT
          set blocklist (ip4.saddr) in { 192.168.1.100 }
          rule
              (ip4.saddr) in blocklist
              DROP"

$ # Add addresses to the blocklist
$ sudo bfcli chain update-set --name my_filter --set-name blocklist --add 192.168.1.101 --add 192.168.1.102

$ # Remove an address from the blocklist
$ sudo bfcli chain update-set --name my_filter --set-name blocklist --remove 192.168.1.100

chain flush

Detach, unload, and discard an existing chain.

Options
  • --name NAME: name of the chain to flush.

Examples

$ # Set an XDP chain and update it
$ sudo bfcli chain set --from-str "chain my_xdp_chain BF_HOOK_XDP ACCEPT"
$ sudo bfcli chain get --name my_xdp_chain
  chain my_xdp_chain BF_HOOK_XDP ACCEPT
      counters policy 0 packets 0 bytes; error 0 packets 0 bytes
$ sudo bfcli chain flush --name my_xdp_chain
$ sudo bfcli chain get --name my_xdp_chain
$ # No output, chain doesn't exist

Filters definition

The following sections will use the dollar sign ($) to prefix values that should be replaced by the user, and brackets ([]) for optional values (whether it's a literal or a user-provided value).

Example of a ruleset:

chain $NAME $HOOK $HOOK_OPTIONS $POLICY
    rule
        $MATCHER
        $VERDICT
    [...]
[...]
A ruleset is composed of chain(s), rule(s), and matcher(s):
  • A chain is a set of rule(s) to match the packet against. It will use the rules to filter packets at a specific location in the kernel: a $HOOK. There can be only one chain defined for a given kernel hook. Chains also have a $POLICY which specify the action to take with the packet if none of the rules matches.
  • A rule defines an action to take on a packet if it matches all its specified criteria. A rule will then apply a defined action to the packet if it's matched.
  • A matcher is a matching criterion within a rule. It can match a specific protocol, a specific field, a network interface... The number of matchers supported by bpfilter and bfcli is constantly growing.

Note

Lines starting with # are comments and bfcli will ignore them.

Chains

Chains are defined such as:

chain $NAME $HOOK{$OPTIONS} $POLICY
With:
  • $NAME: user-defined name for the chain.
  • $HOOK: hook in the kernel to attach the chain to:
    • BF_HOOK_XDP: XDP hook.
    • BF_HOOK_TC_INGRESS: ingress TC hook.
    • BF_HOOK_NF_PRE_ROUTING: similar to nftables and iptables prerouting hook.
    • BF_HOOK_NF_LOCAL_IN: similar to nftables and iptables input hook.
    • BF_HOOK_CGROUP_SKB_INGRESS: ingress cgroup_skb hook.
    • BF_HOOK_CGROUP_SKB_EGRESS: egress cgroup_skb hook.
    • BF_HOOK_NF_FORWARD: similar to nftables and iptables forward hook.
    • BF_HOOK_NF_LOCAL_OUT: similar to nftables and iptables output hook.
    • BF_HOOK_NF_POST_ROUTING: similar to nftables and iptables postrouting hook.
    • BF_HOOK_TC_EGRESS: egress TC hook.
  • $POLICY: action taken if no rule matches the packet, either ACCEPT forward the packet to the kernel, or DROP to discard it. Note while CONTINUE is a valid verdict for rules, it is not supported for chain policy.

$OPTIONS are hook-specific comma separated key value pairs. A given hook option can only be specified once:

.. flat-table::
   :header-rows: 1
   :widths: 2 2 2 12
   :fill-cells:

   * - Option
     - Required by
     - Supported by
     - Notes
   * - ``ifindex=$IFINDEX``
     - ``BF_HOOK_XDP``, ``BF_HOOK_TC``
     - N/A
     - Interface index to attach the program to.
   * - ``cgpath=$CGROUP_PATH``
     - ``BF_HOOK_CGROUP_SKB_INGRESS``, ``BF_HOOK_CGROUP_SKB_EGRESS``
     - N/A
     - Path to the cgroup to attach to.
   * - ``family=$FAMILY``
     - N/A
     - N/A
     - Deprecated, bpfilter will automatically attach Netfilter chains to both IPv4 and IPv6 families.
   * - ``priorities=$INT1-$INT2``
     - ``BF_HOOK_NF_*``
     - N/A
     - ``INT1`` and ``INT2`` are different non-zero integers. Priority values to use when attaching the chain. Two values are required to ensure atomic update of the chain.

Rules

Rules are defined such as:

rule
    [$MATCHER...]
    [$SET...]
    [log link,internet,transport]
    [counter]
    [mark $MARK]
    $VERDICT
With:
  • $MATCHER: zero or more matchers. Matchers are defined later.
  • log: optional. If set, log the requested protocol headers. link will log the link (layer 2) header, internet with log the internet (layer 3) header, and transport will log the transport (layer 4) header. At least one header type is required.
  • counter: optional literal. If set, the filter will counter the number of packets and bytes matched by the rule.
  • mark: optional, $MARK must be a valid decimal or hexadecimal 32-bits value. If set, write the packet's marker value. This marker can be used later on in a rule (see meta.mark) or with a TC filter.
  • $VERDICT: action taken by the rule if the packet is matched against all the criteria: either ACCEPT, DROP, CONTINUE, or REDIRECT. - ACCEPT: forward the packet to the kernel. - DROP: discard the packet. - CONTINUE: continue processing subsequent rules. - REDIRECT $IFACE $DIR: redirect the packet to interface $IFACE in direction $DIR. $IFACE can be an interface name (e.g., "eth0") or an interface index (e.g., "2"). $DIR is either in for ingress or out for egress.

In a chain, as soon as a rule matches a packet, its verdict is applied. If the verdict is ACCEPT, DROP, or REDIRECT, the subsequent rules are not processed. Hence, the rules' order matters. If no rule matches the packet, the chain's policy is applied.

Note CONTINUE means a packet can be counted more than once if multiple rules specify CONTINUE and counter.

Note

REDIRECT is only supported by the following hooks:
  • BF_HOOK_XDP: only out direction is supported (XDP always transmits out of the target interface).
  • BF_HOOK_TC_INGRESS, BF_HOOK_TC_EGRESS: both in and out directions are supported.

REDIRECT is not supported by Netfilter (BF_HOOK_NF_*) or cgroup_skb (BF_HOOK_CGROUP_SKB_*) hooks.

Sets

Sets defines a group of data of the same type. At runtime, the chain will check if the corresponding packet data is in the set, instead of checking against every single value from the set, which makes it much faster.

There are multiple ways to define sets in your ruleset. bpfilter supports named and anonymous sets:

set $NAME $KEY in {
    $ELEMENT_0;
    $ELEMENT_1
}

rule
    $KEY in $NAME
    [...]

rule
    $KEY in { $ELEMENT_0; $ELEMENT_1 }
    [...]

rule
    $KEY in {
        $ELEMENT_0
        $ELEMENT_1
    }
    [...]
With:
  • $NAME: name of the set, for named sets. Allows users to define a set at the beginning of the ruleset, then use it in multiple rules. Sets defined directly in a rule are anonymous, they can't be reused in a different rule. When using a named set, the key used in the rule to refer to the set must be the same as the key used to define the set.
  • $KEY: the set's key, which is the format of the data stored in the set. Keys are defined as ($MATCHER_0 [, $MATCHERS...]). This instructs bpfilter that the key is formed from the payload of the list matchers. For example, (ip4.saddr, ip4.proto) describe the key as the source IPv4 address followed by the IPv4 protocol field. Each matcher defined in the key is called a "component". Parentheses are required even if the key contains a single component.
  • $ELEMENT: elements are the data to store in the set, each component of the key should have a corresponding value in each element. Components of an element are comma-separated, elements themselves are delimited by semicolon or new line.

Here is an example:

set dns (ip4.saddr) in { 1.1.1.1; 1.0.0.1 }

rule
    (ip4.saddr) in dns
    counter
    ACCEPT

rule
    (ip4.saddr, ip4.proto) in {
        192.168.1.1, tcp
        192.168.1.10, udp
        # More can be added...
    }
    ACCEPT

Warning

While the IPv4 and IPv6 snet and dnet matchers are supported in sets, they can be mixed with other matchers. A set key can be a single ip4.snet, ip4.dnet, ip6.snet, ip6.dnet, or a combination of non-network matchers.

Matchers

Matchers are defined such as:

$TYPE [$OP] $PAYLOAD
With:
  • $TYPE: type of the matcher, defined which part of the processed network packet need to be compared against. All the exact matcher types are defined below.
  • $OP: comparison operation, not all $TYPE of matchers support all the existing comparison operators:
    • eq: exact equality.
    • not: inequality.
    • any: match the packet against a set of data defined as the payload. If any of the member of the payload set is found in the packet, the matcher is positive. For example, if you want to match all the icmp and udp packets: ip4.proto any icmp,udp.
    • all: match the packet against a set of data defined as the payload. If all the member of the payload set are found in the packet, the matcher is positive, even if the packet contains more than only the members defined in the payload. For example, to match all the packets containing at least the ACK TCP flag: tcp.flags all ACK.
    • in: matches the packet against a hashed set of reference values. Using the in operator is useful when the packet's data needs to be compared against a large set of different values. Let's say you want to filter 1000 different IPv4 addresses, you can either define 1000 ip4.saddr eq $IP matcher, in which case bpfilter will compare the packet against every IP one after the other. Or you can use (ip4.saddr) in {$IP0,IP1,...} in which case bpfilter will compare the packet's data against the hashed set as a whole in 1 operation.
    • range: matches in a range of values. Formatted as $START-$END. Both $START and $END are included in the range.
  • $PAYLOAD: payload to compare to the processed network packet. The exact payload format depends on $TYPE.

Meta

.. flat-table::
    :header-rows: 1
    :widths: 2 2 1 4 12
    :fill-cells:

    * - Matches
      - Type
      - Operator
      - Payload
      - Notes
    * - Interface
      - ``meta.iface``
      - ``eq``
      - ``$INTERFACE``
      - For chains attached to an ingress hook, ``$INTERFACE`` is the input interface, for chains attached to an egress hook, ``$INTERFACE`` is the output interface. ``$INTERFACE`` must be an interface name (e.g., "eth0", "wlan0") or a decimal interface index (e.g., "1", "2").
    * - L3 protocol
      - ``meta.l3_proto``
      - ``eq``
      - ``$PROTOCOL``
      - ``$PROTOCOL`` must be an internet layer protocol name (e.g. "IPv6", case insensitive), or a valid decimal or hexadecimal `IEEE 802 number`_.
    * - L4 protocol
      - ``meta.l4_proto``
      - ``eq``
      - ``$PROTOCOL``
      - ``$PROTOCOL`` must be a transport layer protocol name (e.g. "ICMP", case insensitive), or a valid decimal `internet protocol number`_.
    * - :rspan:`2` Source port
      - :rspan:`2` ``meta.sport``
      - ``eq``
      - :rspan:`1` ``$PORT``
      - :rspan:`1` ``$PORT`` must be a valid decimal port number.
    * - ``not``
    * - ``range``
      - ``$START-$END``
      - ``$START`` and ``$END`` are valid port values, as decimal integers.
    * - :rspan:`2` Destination port
      - :rspan:`2` ``meta.dport``
      - ``eq``
      - :rspan:`1` ``$PORT``
      - :rspan:`1` ``$PORT`` must be a valid decimal port number.
    * - ``not``
    * - ``range``
      - ``$START-$END``
      - ``$START`` and ``$END`` are valid port values, as decimal integers.
    * - Probability
      - ``meta.probability``
      - ``eq``
      - ``$PROBABILITY``
      - ``$PROBABILITY`` is a valid decimal percentage value (i.e., within [0%, 100%]).
    * - :rspan:`1` Mark
      - :rspan:`1` ``meta.mark``
      - ``eq``
      - :rspan:`1` ``$MARK``
      - :rspan:`1` ``$MARK`` must be a valid decimal or hexadecimal 32-bits value. Incompatible with ``BF_HOOK_XDP`` hook.
    * - ``not``
    * - :rspan:`2` Flow hash
      - :rspan:`2` ``meta.flow_hash``
      - ``eq``
      - :rspan:`1` ``$HASH``
      - :rspan:`1` ``$HASH`` must be a decimal or hexadecimal 32-bits integer. Only compatible with ``BF_HOOK_TC_INGRESS`` and ``BF_HOOK_TC_EGRESS`` hooks.
    * - ``not``
    * - ``range``
      - ``$START-$END``
      - ``$START`` and ``$END`` must be decimal or hexadecimal 32-bits integers, with ``$START <= $END``. Only compatible with ``BF_HOOK_TC_INGRESS`` and ``BF_HOOK_TC_EGRESS`` hooks.
    * - Flow probability
      - ``meta.flow_probability``
      - ``eq``
      - ``$PROBABILITY``
      - ``$PROBABILITY`` is a floating-point percentage value (i.e., within [0%, 100%], e.g., "50%" or "33.33%"). Unlike ``meta.probability`` which uses per-packet randomness, ``meta.flow_probability`` computes a deterministic hash from the packet's 5-tuple (source/destination IP, source/destination port, protocol) ensuring all packets from the same flow get the same match decision. Only applies to IPv4/IPv6 packets with TCP or UDP on L4; packets with other protocols are skipped. Compatible with ``BF_HOOK_XDP``, ``BF_HOOK_TC_INGRESS``, ``BF_HOOK_TC_EGRESS``, ``BF_HOOK_CGROUP_SKB_INGRESS``, and ``BF_HOOK_CGROUP_SKB_EGRESS`` hooks.

IPv4

.. flat-table::
    :header-rows: 1
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    :fill-cells:

    * - Matches
      - Type
      - Operator
      - Payload
      - Notes
    * - :rspan:`2` Source address
      - :rspan:`2` ``ip4.saddr``
      - ``eq``
      - :rspan:`1` ``$ADDR``
      - :rspan:`5` ``$ADDR`` is an IPv4 address in dotted-decimal format, "ddd.ddd.ddd.ddd", where ddd is a decimal number of up to three digits in the range 0 to 255. To filter on an IPv4 network (using an IPv4 address and a subnet mask), see ``ip4.snet`` or ``ip4.dnet``.
    * - ``not``
    * - ``in``
      - ``{$ADDR[,...]}``
    * - :rspan:`2` Destination address
      - :rspan:`2` ``ip4.daddr``
      - ``eq``
      - :rspan:`1` ``$ADDR``
    * - ``not``
    * - ``in``
      - ``{$ADDR[,...]}``
    * - :rspan:`2` Source network
      - :rspan:`2` ``ip4.snet``
      - ``eq``
      - :rspan:`1` ``$ADDR/$MASK``
      - :rspan:`5` ``$ADDR`` is an IPv4 network address in dotted-decimal format, \"ddd.ddd.ddd.ddd\", where ddd is a decimal number of up to three digits in the range 0 to 255, ``$MASK`` is a subnet mask in the range 0 to 32.
    * - ``not``
    * - ``in``
      - ``{$ADDR/$MASK[,...]}``
    * - :rspan:`2` Destination network
      - :rspan:`2` ``ip4.dnet``
      - ``eq``
      - :rspan:`1` ``$ADDR/$MASK``
    * - ``not``
    * - ``in``
      - ``{$ADDR/$MASK[,...]}``
    * - :rspan:`1` Protocol
      - :rspan:`1` ``ip4.proto``
      - ``eq``
      - :rspan:`1` ``$PROTOCOL``
      - :rspan:`1` ``$PROTOCOL`` must be a transport layer protocol name (e.g. "ICMP", case insensitive), or a valid decimal `internet protocol number`_.
    * - ``not``

IPv6

.. flat-table::
    :header-rows: 1
    :widths: 2 2 1 4 12
    :fill-cells:

    * - Matches
      - Type
      - Operator
      - Payload
      - Notes
    * - :rspan:`1` Source address
      - :rspan:`1` ``ip6.saddr``
      - ``eq``
      - :rspan:`3` ``$ADDR``
      - :rspan:`3` ``$ADDR`` must be an IPv6 address composed of 8 hexadecimal numbers (abbreviations are supported). To filter on an IPv6 network (using an IPv6 address and a subnet mask), see ``ip6.snet`` or ``ip6.dnet``.
    * - ``not``
    * - :rspan:`1` Destination address
      - :rspan:`1` ``ip6.daddr``
      - ``eq``
    * - ``not``
    * - :rspan:`2` Source network
      - :rspan:`2` ``ip6.snet``
      - ``eq``
      - :rspan:`1` ``$ADDR/$MASK``
      - :rspan:`5` ``$ADDR`` must be an IPv6 address composed of 8 hexadecimal numbers (abbreviations are supported), ``$MASK`` is a subnet mask in the range 0 to 128.
    * - ``not``
    * - ``in``
      - ``{$ADDR/$MASK[,...]}``
    * - :rspan:`2` Destination network
      - :rspan:`2` ``ip6.dnet``
      - ``eq``
      - :rspan:`1` ``$ADDR/$MASK``
    * - ``not``
    * - ``in``
      - ``{$ADDR/$MASK[,...]}``
    * - :rspan:`1` Next header
      - :rspan:`1` ``ip6.nexthdr``
      - ``eq``
      - :rspan:`3` ``$NEXT_HEADER``
      - :rspan:`3` ``$NEXT_HEADER`` is a transport layer protocol name (e.g. "ICMP", case insensitive), an IPv6 extension header name, or a valid decimal `internet protocol number`_.
    * - ``not``

Tip

The following IPv6 extension header names are recognized by bpfilter: hop, route, frag, ah, dst, mh.

TCP

.. flat-table::
    :header-rows: 1
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    :fill-cells:

    * - Matches
      - Type
      - Operator
      - Payload
      - Notes
    * - :rspan:`3` Source port
      - :rspan:`3` ``tcp.sport``
      - ``eq``
      - :rspan:`1` ``$PORT``
      - :rspan:`2` ``$PORT`` must be a valid decimal port number.
    * - ``not``
    * - ``in``
      - ``{$PORT[;...]}``
    * - ``range``
      - ``$START-$END``
      - ``$START`` and ``$END`` are valid port values, as decimal integers.
    * - :rspan:`3` Destination port
      - :rspan:`3` ``tcp.dport``
      - ``eq``
      - :rspan:`1` ``$PORT``
      - :rspan:`2` ``$PORT`` must be a valid decimal port number.
    * - ``not``
    * - ``in``
      - ``{$PORT[;...]}``
    * - ``range``
      - ``$START-$END``
      - ``$START`` and ``$END`` are valid port values, as decimal integers.
    * - :rspan:`3` Flags
      - :rspan:`3` ``tcp.flags``
      - ``eq``
      - :rspan:`3` ``$FLAG[,...]``
      - :rspan:`3` ``$FLAG`` is a comma-separated list of one or more TCP flags (``fin``, ``syn``, ``rst``, ``psh``, ``ack``, ``urg``, ``ece``, or ``cwr``). Flags are case-insensitive.
    * - ``not``
    * - ``any``
    * - ``all``

Tip

The tcp.flags operators can be confusing, as they can be used to match all, some, or none of the flags available in the TCP header. This section aims to provide clarity to their exact behavior:

  • eq: the TCP header must contain the exact same flags as defined in the rule. The matcher tcp.flags eq syn,ack will match syn,ack, but not syn,ack,fin nor rst.
  • not: opposite of eq, the TCP header must not contain the exact same flags as defined in the rule. The matcher tcp.flags eq syn,ack will match syn,ack,fin or rst, but not syn,ack.
  • any: the TCP header must contain any of the flags defined in the rule. The matcher tcp.flags eq syn,ack will match syn, or ack, or syn,ack, but not fin.
  • all: the TCP header must contain at least the flags defined in the rule. The matcher tcp.flags all syn,ack will match syn,ack,fin, but not syn, or ack,fin.

UDP

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    :fill-cells:

    * - Matches
      - Type
      - Operator
      - Payload
      - Notes
    * - :rspan:`3` Source port
      - :rspan:`3` ``udp.sport``
      - ``eq``
      - :rspan:`1` ``$PORT``
      - :rspan:`2` ``$PORT`` must be a valid decimal port number.
    * - ``not``
    * - ``in``
      - ``{$PORT[;...]}``
    * - ``range``
      - ``$START-$END``
      - ``$START`` and ``$END`` are valid port values, as decimal integers.
    * - :rspan:`3` Destination port
      - :rspan:`3` ``udp.dport``
      - ``eq``
      - :rspan:`1` ``$PORT``
      - :rspan:`2` ``$PORT`` must be a valid decimal port number.
    * - ``not``
    * - ``in``
      - ``{$PORT[;...]}``
    * - ``range``
      - ``$START-$END``
      - ``$START`` and ``$END`` are valid port values, as decimal integers.

ICMP

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    :header-rows: 1
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    :fill-cells:

    * - Matches
      - Type
      - Operator
      - Payload
      - Notes
    * - :rspan:`1` Type
      - :rspan:`1` ``icmp.type``
      - ``eq``
      - :rspan:`1` ``$TYPE``
      - :rspan:`1` ``$TYPE`` is an ICMP type name (e.g. "echo-reply", case insensitive), or a decimal or hexadecimal `ICMP type value`_.
    * - ``not``
    * - :rspan:`1` Code
      - :rspan:`1` ``icmp.code``
      - ``eq``
      - :rspan:`1` ``$CODE``
      - :rspan:`1` ``$CODE`` is a decimal or hexadecimal `ICMP code value`_.
    * - ``not``

Tip

The following ICMP type name are recognized by bpfilter: echo-reply, destination-unreachable, source-quench, redirect, echo-request, time-exceeded, parameter-problem, timestamp-request, timestamp-reply, info-request, info-reply, address-mask-request, address-mask-reply, router-advertisement, router-solicitation.

ICMPv6

.. flat-table::
    :header-rows: 1
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    :fill-cells:

    * - Matches
      - Type
      - Operator
      - Payload
      - Notes
    * - :rspan:`1` Type
      - :rspan:`1` ``icmpv6.type``
      - ``eq``
      - :rspan:`1` ``$TYPE``
      - :rspan:`1` ``$TYPE`` is an ICMPv6 type name (e.g. "echo-reply", case insensitive), or a decimal or hexadecimal `ICMPv6 type value`_.
    * - ``not``
    * - :rspan:`1` Code
      - :rspan:`1` ``icmpv6.code``
      - ``eq``
      - :rspan:`1` ``$CODE``
      - :rspan:`1` ``$CODE`` is a decimal or hexadecimal `ICMPv6 code value`_.
    * - ``not``

Tip

The following ICMPv6 type name are recognized by bpfilter: destination-unreachable, packet-too-big, time-exceeded, echo-request, echo-reply, mld-listener-query, mld-listener-report, mld-listener-reduction, nd-router-solicit, nd-router-advert, nd-neighbor-solicit, nd-neighbor-advert, parameter-problem, mld2-listener-report.