ping – Minimal C++ ICMP Ping Tool

A lightweight, educational ping implementation in C++ using raw sockets.

Usage

sudo ./ping [-c count] <host>

• -c count: Number of pings (default: 4)
• <host>: Hostname or IP (IPv4 only)

Requires sudo due to SOCK_RAW.

How It Works

1. Resolves host to IPv4 address via getaddrinfo.
2. Creates raw ICMP socket (IPPROTO_ICMP).
3. Sends Echo Request (type 8) with:
   • Process ID as identifier
   • Sequence number
   • 56-byte payload
   • Correct ICMP checksum
4. Receives reply, verifies:
   • Type 0 (Echo Reply)
   • Matching ID and sequence
5. Measures RTT and prints stats.

TODO

• Add IPv6 support (AF_INET6, ICMPv6)
• Implement traceroute (-I style with TTL)

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Full technical breakdown:
Read the blog post