Introduction to Tool-Driven Playbook

The Linux networking ecosystem relies heavily on tools like bpftool, ip -d, ethtool, and targeted captures to manage and troubleshoot traffic control (tc) and eXpress Data Path (XDP) programs.

Identifying tc Program Attachments

Using bpftool to List Attached Programs

To list all BPF programs attached to the eth0 interface, use the following command:

bpftool net dev eth0 prog

This command displays a list of attached programs, including their type (e.g., tc), ID, and other relevant details.

Utilizing ip -d to Verify Program Attachments

To display detailed information about the eth0 interface, including attached tc programs, use:

ip -d link show eth0

This command displays detailed information about the interface, including any attached tc programs and their configurations.

ethtool Command Examples for tc Attachment Verification

To display the offload settings for the eth0 interface, use:

ethtool -k eth0

This command displays the interface’s offload settings, including any tc programs that are offloaded to the hardware.

Identifying XDP Program Attachments

bpftool Commands for XDP Program Inspection

To list all XDP programs attached to the eth0 interface, use:

bpftool net dev eth0 xdp

This command displays a list of attached XDP programs, including their ID and other relevant details.

ip -d Options for XDP Attachment Identification

To display detailed information about the eth0 interface, including any attached XDP programs, use:

ip -d link show eth0

This command displays detailed information about the interface, including any attached XDP programs and their configurations.

ethtool Usage for XDP Attachment Verification

To display the offload settings for the eth0 interface, use:

ethtool -k eth0

This command displays the interface’s offload settings, including any XDP programs that are offloaded to the hardware.

Understanding Program Modes

Native XDP Mode Identification

To identify native XDP mode, use bpftool to inspect the XDP program’s attachment and configuration:

bpftool net dev eth0 xdp show

This command displays detailed information about the XDP program’s attachment and configuration, including its mode of operation.

Offloaded XDP Mode Detection

To detect offloaded XDP mode, use ethtool to check the interface’s offload settings:

ethtool -k eth0

This command displays the interface’s offload settings, including any XDP programs that are offloaded to the hardware.

Troubleshooting Attachment Issues

Using Targeted Captures for Debugging

To debug attachment issues, use targeted captures to capture specific network traffic and analyze it to identify the root cause of the issue:

tcpdump -i eth0 -w capture.pcap

This command captures traffic on the eth0 interface and saves it to a file for analysis.

bpftool and ethtool Troubleshooting Examples

To troubleshoot attachment issues, use bpftool and ethtool to inspect program attachments and configurations:

bpftool net dev eth0 prog
ethtool -k eth0

These commands display information about attached programs and interface settings.

Reliable Artifacts and Misleading Indicators

Short Artifacts for Proving Program Attachments

Short artifacts, such as bpftool output or ip -d output, can be used to prove program attachments:

bpftool net dev eth0 prog
ip -d link show eth0

These commands display information about attached programs and interface settings.

Best Practices for Reliable Artifact Collection

Best practices for reliable artifact collection include using a combination of tools and commands, verifying program attachments and configurations, and monitoring network performance.

Code and CLI Examples

bpftool Code Snippets for Attachment Verification

To verify the attachment of tc and XDP programs, use:

bpftool net dev eth0 prog
bpftool net dev eth0 xdp show

These commands display information about attached programs and interface settings.

ethtool CLI Examples for XDP and tc Inspection

To inspect the interface’s offload settings and optimize interface settings, use:

ethtool -k eth0
ethtool -K eth0

These commands display information about interface settings and optimize them for better performance.

ip -d Command Examples for Program Attachment Identification

To display detailed information about the network interface and its attached programs, use:

ip -d link show eth0
ip -d addr show eth0

These commands display information about attached programs and interface settings.

Targeted Capture Code Examples for Debugging

To capture specific network traffic and analyze it to identify the root cause of attachment issues, use:

tcpdump -i eth0 -w capture.pcap
Wireshark capture.pcap

These commands capture traffic on the eth0 interface and analyze it to identify issues.