ether_aton_r - Linux
Overview
The ether_aton_r
command converts a presentation format MAC address (e.g., "01:23:45:67:89:ab") into a 48-bit integer where every 8 bits corresponds to one byte in the MAC. It is primarily useful for working with MAC addresses in memory or for creating data structures that require binary representation.
Syntax
ether_aton_r <MAC address> <result variable>
Parameters:
<MAC address>
: Presentation format MAC address (e.g., "01:23:45:67:89:ab").<result variable>
: Variable to store the converted 48-bit integer.
Options/Flags
None
Examples
Simple Conversion:
ether_aton_r "01:23:45:67:89:ab" mac_int
Storing in Array:
ether_aton_r "01:23:45:67:89:ab" mac_array[0]
Complex Integration:
# Create a script to filter packets by MAC address
#!/bin/bash
# Process arguments
if [ $# != 2 ]; then
echo "Usage: $0 <MAC address> <interface>"
exit 1
fi
# Convert MAC address
ether_aton_r $1 mac_int
# Construct filter syntax
filter="ether host $mac_int"
# Apply filter to interface
tcpdump -i $2 -n -e "ether host $mac_int"
Common Issues
Invalid MAC Address:
If the provided MAC address is not in a valid format, ether_aton_r
will return an error. Ensure the address follows the "01:23:45:67:89:ab" pattern.
Variable Type:
The result variable
must be a signed integer with a length of 48 bits or more. Using an insufficiently sized variable can lead to data loss.
Integration
- Combine with
ether_ntoa_r
to convert binary MAC addresses back to presentation format. - Use with
tcpdump
ortshark
to filter packets based on MAC addresses. - Integrate into scripts for automating network analysis or management tasks.
Related Commands
- ether_aton
- ether_ntoa