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bpftool-net.rst

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bpftool-net

tool for inspection of networking related bpf prog attachments

Manual section:8

SYNOPSIS

bpftool [OPTIONS] net COMMAND

OPTIONS := { |COMMON_OPTIONS| }

COMMANDS := { show | list | attach | detach | help }

NET COMMANDS

bpftool net { show | list } [ dev NAME ]
bpftool net attach ATTACH_TYPE PROG dev NAME [ overwrite ]
bpftool net detach ATTACH_TYPE dev NAME
bpftool net help

PROG := { id PROG_ID | pinned FILE | tag PROG_TAG | name PROG_NAME }
ATTACH_TYPE := { xdp | xdpgeneric | xdpdrv | xdpoffload | tcx_ingress | tcx_egress }

DESCRIPTION

bpftool net { show | list } [ dev NAME ]

List bpf program attachments in the kernel networking subsystem.

Currently, device driver xdp attachments, tcx, netkit and old-style tc classifier/action attachments, flow_dissector as well as netfilter attachments are implemented, i.e., for program types BPF_PROG_TYPE_XDP, BPF_PROG_TYPE_SCHED_CLS, BPF_PROG_TYPE_SCHED_ACT, BPF_PROG_TYPE_FLOW_DISSECTOR, BPF_PROG_TYPE_NETFILTER.

For programs attached to a particular cgroup, e.g., BPF_PROG_TYPE_CGROUP_SKB, BPF_PROG_TYPE_CGROUP_SOCK, BPF_PROG_TYPE_SOCK_OPS and BPF_PROG_TYPE_CGROUP_SOCK_ADDR, users can use bpftool cgroup to dump cgroup attachments. For sk_{filter, skb, msg, reuseport} and lwt/seg6 bpf programs, users should consult other tools, e.g., iproute2.

The current output will start with all xdp program attachments, followed by all tcx, netkit, then tc class/qdisc bpf program attachments, then flow_dissector and finally netfilter programs. Both xdp programs and tcx/netkit/tc programs are ordered based on ifindex number. If multiple bpf programs attached to the same networking device through tc, the order will be first all bpf programs attached to tcx, netkit, then tc classes, then all bpf programs attached to non clsact qdiscs, and finally all bpf programs attached to root and clsact qdisc.

bpftool net attach ATTACH_TYPE PROG dev NAME [ overwrite ]

Attach bpf program PROG to network interface NAME with type specified by ATTACH_TYPE. Previously attached bpf program can be replaced by the command used with overwrite option. Currently, only XDP-related modes are supported for ATTACH_TYPE.

ATTACH_TYPE can be of: xdp - try native XDP and fallback to generic XDP if NIC driver does not support it; xdpgeneric - Generic XDP. runs at generic XDP hook when packet already enters receive path as skb; xdpdrv - Native XDP. runs earliest point in driver's receive path; xdpoffload - Offload XDP. runs directly on NIC on each packet reception; tcx_ingress - Ingress TCX. runs on ingress net traffic; tcx_egress - Egress TCX. runs on egress net traffic;

bpftool net detach ATTACH_TYPE dev NAME
Detach bpf program attached to network interface NAME with type specified by ATTACH_TYPE. To detach bpf program, same ATTACH_TYPE previously used for attach must be specified. Currently, only XDP-related modes are supported for ATTACH_TYPE.
bpftool net help
Print short help message.

OPTIONS

EXAMPLES

# bpftool net
xdp:
eth0(2) driver id 198

tc:
eth0(2) htb name prefix_matcher.o:[cls_prefix_matcher_htb] id 111727 act []
eth0(2) clsact/ingress fbflow_icmp id 130246 act []
eth0(2) clsact/egress prefix_matcher.o:[cls_prefix_matcher_clsact] id 111726
eth0(2) clsact/egress cls_fg_dscp id 108619 act []
eth0(2) clsact/egress fbflow_egress id 130245

# bpftool -jp net
[{
        "xdp": [{
                "devname": "eth0",
                "ifindex": 2,
                "mode": "driver",
                "id": 198
            }
        ],
        "tc": [{
                "devname": "eth0",
                "ifindex": 2,
                "kind": "htb",
                "name": "prefix_matcher.o:[cls_prefix_matcher_htb]",
                "id": 111727,
                "act": []
            },{
                "devname": "eth0",
                "ifindex": 2,
                "kind": "clsact/ingress",
                "name": "fbflow_icmp",
                "id": 130246,
                "act": []
            },{
                "devname": "eth0",
                "ifindex": 2,
                "kind": "clsact/egress",
                "name": "prefix_matcher.o:[cls_prefix_matcher_clsact]",
                "id": 111726,
            },{
                "devname": "eth0",
                "ifindex": 2,
                "kind": "clsact/egress",
                "name": "cls_fg_dscp",
                "id": 108619,
                "act": []
            },{
                "devname": "eth0",
                "ifindex": 2,
                "kind": "clsact/egress",
                "name": "fbflow_egress",
                "id": 130245,
            }
        ]
    }
]

# bpftool net attach xdpdrv id 16 dev enp6s0np0
# bpftool net
xdp:
enp6s0np0(4) driver id 16

# bpftool net attach xdpdrv id 16 dev enp6s0np0
# bpftool net attach xdpdrv id 20 dev enp6s0np0 overwrite
# bpftool net
xdp:
enp6s0np0(4) driver id 20

# bpftool net attach xdpdrv id 16 dev enp6s0np0
# bpftool net detach xdpdrv dev enp6s0np0
# bpftool net
xdp:

# bpftool net attach tcx_ingress name tc_prog dev lo
# bpftool net

::
tc: lo(1) tcx/ingress tc_prog prog_id 29

# bpftool net attach tcx_ingress name tc_prog dev lo
# bpftool net detach tcx_ingress dev lo
# bpftool net

::
tc: