Feature: Probe Generation

Purpose

The project observes IPv4 addresses that are unlikely to host an ordinary service. The first step is a deterministic list of those addresses, so that every later phase works from the same set.

The list is the ip_probe list: IPv4 addresses that are composed of four prime octets and are valid for routing across the Internet.

Requirements

• PROBE-GEN-R001 — An ip_probe is an IPv4 address whose four octets are each a prime number.
• PROBE-GEN-R002 — An ip_probe must be globally reachable unicast: it must not fall inside an IANA special-purpose block that is private, loopback, link-local, shared, documentation, benchmark, multicast, reserved, or broadcast.
• PROBE-GEN-R003 — Only three excluded blocks intersect the four-prime-octet space: 127.0.0.0/8, 224.0.0.0/4, and 240.0.0.0/4.
• PROBE-GEN-R004 — The list must contain 7,400,808 addresses: 54 primes per octet, 54^4 addresses, less 7 first-octet classes of 54^3 addresses each.
• PROBE-GEN-R005 — The list must be written to dataflow.out/01_ip_probe.json in ascending order.
• PROBE-GEN-R006 — The list must be a JSON array of dotted-quad strings, one address per line.
• PROBE-GEN-R007 — Generation must be deterministic: the same inputs produce the same file.
• PROBE-GEN-R008 — Generation must not require network access.
• PROBE-GEN-R009 — The feature must provide a count-only mode and a verification mode.
• PROBE-GEN-R010 — Verification must reject an address that is not an ip_probe and an address list that is not strictly ascending.
• PROBE-GEN-R011 — A probe file that already exists must be kept, not rewritten: generation must verify it and report that it was reused.
• PROBE-GEN-R012 — The file must be written again only when the caller asks for it with --refresh.
• PROBE-GEN-R013 — A file that fails verification must be regenerated, and the failure must be reported.

Behavior

• python3 sources/ip_probe_generate.py --output dataflow.out/01_ip_probe.json writes the list and prints the number of addresses written.
• python3 sources/ip_probe_generate.py --count-only prints the number of addresses without writing a file.
• python3 sources/ip_probe_generate.py --first N --output FILE writes the first N addresses, which supports tests.
• python3 sources/ip_probe_generate.py --verify FILE validates a file, exits nonzero on a violation, and prints the count, the first address, and the last address.
• When the output file already exists, the program prints reuse: <file> count=N first=<address> last=<address> and writes nothing.
• --refresh writes the file again and prints write: <file> count=N.
• The first address of the list is 2.2.2.2.
• The last address of the list is 223.251.251.251.

Dependencies

• None.