d8208685a2
Reactor/loop-pool engine with TCP/µTP/MSE transports, per-connection pipelining, priority-driven piece selection with endgame, and the Python FFI test harness. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
134 lines
6.2 KiB
C
134 lines
6.2 KiB
C
/*
|
|
* peer.h - Legacy single-peer ABI, now a thin compatibility shim over the
|
|
* multi-peer engine (engine.h). A peer_handle is a private 1-loop / 1-torrent /
|
|
* 1-peer engine; the semantics below are unchanged so existing callers and
|
|
* tests keep working. New code should use engine.h directly.
|
|
*/
|
|
#ifndef TORRENT_PEER_H
|
|
#define TORRENT_PEER_H
|
|
|
|
#include <stdint.h>
|
|
|
|
#include "engine.h" /* PEER_BLOCK_SIZE, peer_state, peer_error */
|
|
|
|
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif
|
|
|
|
/*
|
|
* Immutable configuration passed to peer_create(). The arrays are copied, so
|
|
* the caller need not keep them alive afterwards.
|
|
*/
|
|
typedef struct {
|
|
uint8_t info_hash[20]; /* torrent info-hash (BitTorrent v1, SHA-1) */
|
|
uint8_t peer_id[20]; /* our 20-byte peer id */
|
|
uint64_t piece_length; /* bytes per piece (last piece may be shorter) */
|
|
uint64_t total_size; /* total torrent payload size */
|
|
uint32_t num_pieces; /* number of pieces */
|
|
uint32_t num_slots; /* arena depth in 16 KiB slots (0 => default) */
|
|
uint32_t max_pipeline; /* cap on outstanding block requests (0 => def) */
|
|
uint32_t request_timeout_ms; /* re-request a block after this long with no
|
|
* reply (0 => default). Guards against silent
|
|
* request drops. */
|
|
uint32_t recv_buffer_bytes; /* SO_RCVBUF override; 0 => leave kernel
|
|
* autotuning alone (recommended). */
|
|
} peer_config;
|
|
|
|
/*
|
|
* One received block. The payload lives at:
|
|
* (uint8_t*)peer_arena_base(h) + (uint64_t)slot * PEER_BLOCK_SIZE
|
|
* and stays valid until the slot is returned with peer_release_slot().
|
|
* 16 bytes, trivially copyable, no pointers (ABI/relocation friendly).
|
|
*/
|
|
typedef struct {
|
|
uint32_t piece; /* piece index */
|
|
uint32_t begin; /* byte offset of this block within the piece */
|
|
uint32_t len; /* block length in bytes (<= PEER_BLOCK_SIZE) */
|
|
uint32_t slot; /* arena slot holding the payload */
|
|
} block_desc;
|
|
|
|
/* Snapshot of peer progress; filled by peer_get_status(). */
|
|
typedef struct {
|
|
int32_t state; /* peer_state */
|
|
int32_t error; /* peer_error */
|
|
uint64_t bytes_received; /* total payload bytes delivered to ready ring*/
|
|
uint64_t blocks_received; /* total blocks delivered */
|
|
uint32_t outstanding; /* requests sent but not yet received */
|
|
uint32_t free_slots; /* arena slots currently available */
|
|
uint32_t pipeline_target; /* current adaptive in-flight target (blocks) */
|
|
double rate_bps; /* EWMA download rate, bytes/sec */
|
|
double rtt_min_ms; /* smallest observed request->block RTT */
|
|
} peer_status;
|
|
|
|
typedef struct peer_handle peer_handle;
|
|
|
|
/* Lifecycle ------------------------------------------------------------- */
|
|
|
|
/* Allocate a peer and its arena/rings. Returns NULL on bad config or OOM. */
|
|
peer_handle *peer_create(const peer_config *cfg);
|
|
|
|
/* Connect + handshake on a new network thread. ip is dotted-quad IPv4.
|
|
* Returns 0 if the thread launched, negative on immediate failure. The actual
|
|
* connection result surfaces asynchronously via peer_get_status(). */
|
|
int peer_start(peer_handle *h, const char *ip, uint16_t port);
|
|
|
|
/*
|
|
* Piece selection is priority-driven. The harness supplies one priority byte
|
|
* per piece; the peer always works on the highest-priority piece that
|
|
* (a) the remote peer actually HAS (per its bitfield/have messages), and
|
|
* (b) has not already been fully requested,
|
|
* breaking ties toward the lowest piece index. Priority 0 means "do not
|
|
* request". Re-evaluation happens at every piece boundary, so updating
|
|
* priorities while running steers the download live (sequential, rarest-first,
|
|
* deadline ramps, or any mix). The peer never assumes the remote has a piece it
|
|
* has not advertised, which is the key fix over a fixed in-order schedule.
|
|
*/
|
|
|
|
/* Replace the whole priority vector. `count` must equal num_pieces. Does not
|
|
* touch the "already requested" state. Thread-safe. Returns 0, or negative if
|
|
* count != num_pieces. */
|
|
int peer_set_priorities(peer_handle *h, const uint8_t *priorities, uint32_t count);
|
|
|
|
/* Update one piece's priority. Thread-safe. Negative if out of range. */
|
|
int peer_set_priority(peer_handle *h, uint32_t piece_index, uint8_t priority);
|
|
|
|
/* Re-arm a piece for (re-)download, clearing its internal "already requested"
|
|
* mark so it becomes selectable again. Newly created peers start fully armed,
|
|
* so this is only needed to retry a piece that failed hash verification.
|
|
* Thread-safe. Negative if out of range. */
|
|
int peer_request_piece(peer_handle *h, uint32_t piece_index);
|
|
|
|
/* Stop the network thread and close the socket. Idempotent. */
|
|
void peer_stop(peer_handle *h);
|
|
|
|
/* Free the peer and its arena. The arena pointer is invalid afterwards. */
|
|
void peer_destroy(peer_handle *h);
|
|
|
|
/* Data plane ------------------------------------------------------------ */
|
|
|
|
/* Base of the block arena. Wrap [base, base+peer_arena_bytes()) in a Python
|
|
* memoryview once and slice it per block for zero-copy reads. */
|
|
void *peer_arena_base(const peer_handle *h);
|
|
uint64_t peer_arena_bytes(const peer_handle *h);
|
|
|
|
/* Drain up to max completed blocks into out[]. Returns the count (0..max),
|
|
* never blocks. Call from the single harness consumer thread. */
|
|
uint32_t peer_poll_ready(peer_handle *h, block_desc *out, uint32_t max);
|
|
|
|
/* Return a consumed slot so the peer can reuse it. This is what unblocks new
|
|
* requests (credit-based flow control). */
|
|
void peer_release_slot(peer_handle *h, uint32_t slot);
|
|
|
|
/* Block until ready blocks are available or timeout_ms elapses (negative =
|
|
* wait forever). Returns 1 if readable, 0 on timeout, negative on error.
|
|
* Optional: callers may instead poll peer_poll_ready() directly. */
|
|
int peer_wait(peer_handle *h, int timeout_ms);
|
|
|
|
/* Fill *out with a status snapshot. */
|
|
void peer_get_status(const peer_handle *h, peer_status *out);
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
|
|
#endif /* TORRENT_PEER_H */
|