---
name: "dnsjit.input.fpcap"
section: "3"
platform: "linux"
package: "dnsjit"
version: "1.5.0-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/dnsjit.input.fpcap"
---

# dnsjit.input.fpcap(3)

Read input from a PCAP file using fopen()

## NAME

dnsjit.input.fpcap - Read input from a PCAP file using fopen()

## SYNOPSIS

  local input = require("dnsjit.input.fpcap").new()\
   input:open("file.pcap")\
   input:receiver(filter\_or\_output)\
   input:run()

## DESCRIPTION

Read input from a PCAP file using standard library function **fopen()** and parse the PCAP without libpcap. After opening a file and reading the PCAP header, the attributes are populated.

### Attributes

- is\_swapped

  Indicate if the byte order in the PCAP is in reverse order of the host.

- is\_nanosec

  Indicate if the time stamps are in nanoseconds or not.

- magic\_number

  Magic number.

- version\_major

  Major version number.

- version\_minor

  Minor version number.

- thiszone

  GMT to local correction.

- sigfigs

  Accuracy of timestamps.

- snaplen

  Max length of captured packets, in octets.

- network

  The link type found in the PCAP header, see https://www.tcpdump.org/linktypes.html .

- linktype

  The data link type, mapped from *network*.

### Functions

- **Fpcap.new**()

  Create a new Fpcap input.

- **Fpcap:log**()

  Return the Log object to control logging of this instance or module.

- **Fpcap:receiver**(o)

  Set the receiver to pass objects to.

- **Fpcap:produce**()

  Return the C functions and context for producing objects.

- **Fpcap:fadvise\_sequential**()

  Use **posix\_fadvise()** to indicate sequential reading (if supported), may increase performance. MUST be called before **open()**.

- **Fpcap:open**(file)

  Open a PCAP file for processing and read the PCAP header. Returns 0 on success.

- **Fpcap:openfp**(fp)

  Open a PCAP file for processing and read the PCAP header using a file descriptor, for example **io.stdin** or with **io.open()**. Will not take ownership of the file descriptor. Returns 0 on success.

- **Fpcap:run**()

  Start processing packets and send each packet read to the receiver. Returns 0 if all packets was read successfully.

- **Fpcap:packets**()

  Return the number of packets seen.

## AUTHORS and CONTRIBUTORS

Jerry Lundström (DNS-OARC), Tomáš Křížek (CZ.NIC), Petr Špaček (ISC)

Maintained by DNS-OARC

*https://www.dns-oarc.net/*

## BUGS

For issues and feature requests please use:

*https://github.com/DNS-OARC/dnsjit/issues*

For question and help please use:

*admin@dns-oarc.net*