---
name: "probe::netfilter.arp.in"
section: "3stap"
platform: "linux"
package: "systemtap-doc"
version: "5.1-5"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/probe::netfilter.arp.in"
---

# probe::netfilter.arp.in(3stap)

\- Called for each incoming ARP packet

## NAME

probe::netfilter.arp.in - - Called for each incoming ARP packet

## SYNOPSIS

```
netfilter.arp.in
```

## VALUES

*arphdr*

Address of ARP header

*ar\_sha*

Ethernet+IP only (ar\_pro==0x800): source hardware (MAC) address

*ar\_op*

ARP opcode (command)

*nf\_repeat*

Constant used to signify a 'repeat' verdict

*ar\_tip*

Ethernet+IP only (ar\_pro==0x800): target IP address

*length*

The length of the packet buffer contents, in bytes

*nf\_drop*

Constant used to signify a 'drop' verdict

*indev\_name*

Name of network device packet was received on (if known)

*data\_hex*

A hexadecimal string representing the packet buffer contents

*nf\_accept*

Constant used to signify an 'accept' verdict

*ar\_hrd*

Format of hardware address

*nf\_stolen*

Constant used to signify a 'stolen' verdict

*ar\_pln*

Length of protocol address

*ar\_tha*

Ethernet+IP only (ar\_pro==0x800): target hardware (MAC) address

*ar\_sip*

Ethernet+IP only (ar\_pro==0x800): source IP address

*pf*

Protocol family -- always “arp”

*outdev*

Address of net\_device representing output device, 0 if unknown

*indev*

Address of net\_device representing input device, 0 if unknown

*ar\_pro*

Format of protocol address

*outdev\_name*

Name of network device packet will be routed to (if known)

*nf\_queue*

Constant used to signify a 'queue' verdict

*ar\_data*

Address of ARP packet data region (after the header)

*nf\_stop*

Constant used to signify a 'stop' verdict

*ar\_hln*

Length of hardware address

*data\_str*

A string representing the packet buffer contents

## SEE ALSO0

[*tapset::netfilter*(3stap)](/tapset::netfilter/3stap.md)