port.h File Reference

Detailed Description

Range-checked conversion of an untrusted integer to a TCP/UDP port.

JSON-RPC and config surfaces hand port numbers around as a wide signed integer, but the socket APIs take a u16. Narrowing with a bare static_cast<u16> silently wraps: 70000 becomes 4464, so a request that should have been rejected instead targets a completely different endpoint and the failure surfaces much later as a confusing connection error (FastLED#3956).

A low-side-only guard (port > 0 ? static_cast<u16>(port) : 0) does not help — it rejects 65536 only by the accident of it truncating to zero, while 65537 still slips through as port 1.

Definition in file port.h.

#include "fl/stl/int.h"
#include "fl/stl/optional.h"

Include dependency graph for port.h:

Go to the source code of this file.

Namespaces
namespace	fl
	Base definition for an LED controller.
namespace	fl::net

Functions
fl::optional< u16 >	fl::net::tryParsePort (i64 value)
	Convert an untrusted integer to a port number.

Variables
constexpr i64	fl::net::kMaxPort = 65535
	Highest port representable in the 16-bit wire field.
constexpr i64	fl::net::kMinPort = 1
	Lowest port a caller may request.