Crate i2pd_sys 

Raw bindgen-generated FFI bindings to a C shim over libi2pd (PurpleI2P/i2pd) — a real I2P router built in-process, not a client for a separately-running i2pd daemon.

Everything here is generated from shim/shim.h, the only header bindgen runs against; libi2pd’s own C++ headers use std::shared_ptr/STL types with no stable C ABI. That file documents each function. README.md covers the build, the trimmed attack surface, network participation, and the FIPS backend.

use i2pd_sys::*;
use std::ffi::CString;

unsafe {
    let app_name = CString::new("my-app").unwrap();
    i2pd_init(app_name.as_ptr()); // before anything else
    i2pd_start();

    let dest = i2pd_create_transient_destination();
    assert!(!dest.is_null());

    i2pd_destroy_destination(dest);
    i2pd_stop();
    i2pd_terminate();
}

Safety

i2pd_init must be called before anything else. Every I2pdDestination/I2pdStream pointer must be destroyed exactly once via the matching i2pd_destroy_* and never used afterwards. i2pd_free_buffer takes the length i2pd_generate_keys reported and wipes the buffer first: it holds a private key, and plain free would leave the bytes readable in the heap.

The four lifecycle calls share one mutex held across the underlying libi2pd call, so a repeated or out-of-order call is a no-op rather than a second pass over libi2pd’s non-reentrant globals, and a racing caller blocks until the transition it observed has finished. terminate stops a still-running router first.

i2pd_stream_send and i2pd_stream_receive are safe to call concurrently on the same stream — each posts work onto i2pd’s io_service and blocks the calling thread on a condition variable, as i2pd’s own SAM/BOB bridges do. The i2pd_accept_stream callback runs on i2pd’s thread and must return quickly, or it stalls the event loop for every destination on the router.

Every shim function catches all C++ exceptions internally, including that callback, so nothing unwinds across the extern "C" boundary. Failures surface as NULL/0/-1, not panics.

Features

aws-lc (default) links AWS-LC; fips swaps in the FIPS-validated module. fips wins if both end up enabled — build.rs emits link directives for one backend only, and the two use per-version-prefixed symbol names, so the other is inert.

transit (default) carries other users’ tunnels. Building without it compiles the tunnel build-request path out of libi2pd entirely, whatever the runtime settings say; i2pd_accepts_transit reports what the build supports.

Structs

I2pdDestination

I2pdStream

Functions

i2pd_accept_stream^⚠

i2pd_accepts_transit^⚠

i2pd_create_persistent_destination^⚠

i2pd_create_stream^⚠

i2pd_create_transient_destination^⚠

i2pd_destination_b32_address^⚠

i2pd_destination_ident_hash^⚠

i2pd_destroy_destination^⚠

i2pd_destroy_stream^⚠

i2pd_free_buffer^⚠

i2pd_free_string^⚠

i2pd_generate_keys^⚠

i2pd_init^⚠

i2pd_set_accepts_transit^⚠

i2pd_set_bandwidth_limit^⚠

i2pd_set_floodfill^⚠

i2pd_set_max_transit_tunnels^⚠

i2pd_set_share_percent^⚠

i2pd_start^⚠

i2pd_stop^⚠

i2pd_stream_close^⚠

i2pd_stream_is_open^⚠

i2pd_stream_receive^⚠

i2pd_stream_send^⚠

i2pd_terminate^⚠

i2pd_test_mlkem_roundtrip^⚠

Type Aliases

I2pdAcceptCallback