PacketEye

pcap-based traffic analyzer — live capture or offline parsing with per-IP/per-port statistics.

Overview

PacketEye reads packet captures (live or from a .pcap file) and produces a traffic summary: packet/byte totals, protocol mix, TCP handshake counts, top talkers, and top ports. It performs a minimal hand-rolled Ethernet → IPv4 → TCP/UDP/ICMP parse — enough for solid statistics without heavy dependencies.

Usage

packeteye live <iface> [count]   capture live (count=0 for infinite)
packeteye file <dump.pcap>       parse offline capture

EXAMPLES:
  sudo packeteye live eth0
  packeteye file capture.pcap
  sudo packeteye live wlan0 1000

Note: live capture requires root/CAP_NET_RAW (or the equivalent capabilities for the interface).

What it reports

Packet parsing

The analyzer understands:

• Ethernet — 14-byte header, EtherType dispatch (0x0800 IPv4; 0x86dd IPv6 is skipped for detailed parsing)
• IPv4 — IHL-based header parsing, protocol field, source/dest addresses
• TCP — source/dest ports, SYN (0x02) and ACK (0x10) flags
• UDP — source/dest ports
• ICMP — counted only

All parsing is bounds-checked; truncated packets are counted but skipped.

Example output

[*] PacketEye 1.0.0 | listening on eth0 (promisc)
[*] Ctrl+C to stop

=== report: live eth0 (1000 pkts) ===
packets: 1000 | bytes: 742133
protocols: tcp=812 udp=140 icmp=44 other=4
tcp handshakes: syn=23 synack=21

top talkers (by packets):
     192.168.1.10          512
      10.0.0.1             240
        ...

top ports (by ports):
  443        621
  80         132
  53          78

Offline analysis

# Capture with tcpdump, analyze offline
sudo tcpdump -i eth0 -w capture.pcap
packeteye file capture.pcap

Implementation notes

• pcap::Capture::from_device with promiscuous mode, 65535 snaplen, 200 ms timeout
• Live loop treats TimeoutExpired as "keep waiting"
• Statistics use HashMap<Ipv4Addr, u64> and HashMap<u16, u64>, sorted descending before printing
• Graceful error messages for missing interfaces or unreadable files