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transmission/libtransmission/announcer-udp.cc

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// This file Copyright © 2010-2022 Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0), GPLv3 (SPDX: GPL-3.0),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#include <cerrno> /* errno, EAFNOSUPPORT */
#include <cstring> /* memset() */
#include <ctime>
#include <string_view>
#include <vector>
#include <event2/buffer.h>
#include <event2/dns.h>
#include <event2/util.h>
#define LIBTRANSMISSION_ANNOUNCER_MODULE
#include "transmission.h"
#include "announcer.h"
#include "announcer-common.h"
#include "crypto-utils.h" /* tr_rand_buffer() */
#include "log.h"
#include "peer-io.h"
#include "peer-mgr.h" /* tr_peerMgrCompactToPex() */
#include "ptrarray.h"
#include "session.h"
#include "tr-assert.h"
#include "tr-udp.h"
#include "utils.h"
#define dbgmsg(key, ...) tr_logAddDeepNamed(key.c_str(), __VA_ARGS__)
using namespace std::literals;
/****
*****
****/
static void tau_sockaddr_setport(struct sockaddr* sa, tr_port port)
{
if (sa->sa_family == AF_INET)
{
TR_DISCARD_ALIGN(sa, struct sockaddr_in*)->sin_port = htons(port);
}
else if (sa->sa_family == AF_INET6)
{
TR_DISCARD_ALIGN(sa, struct sockaddr_in6*)->sin6_port = htons(port);
}
}
static int tau_sendto(tr_session const* session, struct evutil_addrinfo* ai, tr_port port, void const* buf, size_t buflen)
{
auto sockfd = tr_socket_t{};
if (ai->ai_addr->sa_family == AF_INET)
{
sockfd = session->udp_socket;
}
else if (ai->ai_addr->sa_family == AF_INET6)
{
sockfd = session->udp6_socket;
}
else
{
sockfd = TR_BAD_SOCKET;
}
if (sockfd == TR_BAD_SOCKET)
{
errno = EAFNOSUPPORT;
return -1;
}
tau_sockaddr_setport(ai->ai_addr, port);
return sendto(sockfd, static_cast<char const*>(buf), buflen, 0, ai->ai_addr, ai->ai_addrlen);
}
/****
*****
****/
static uint32_t evbuffer_read_ntoh_32(struct evbuffer* buf)
{
auto val = uint32_t{};
evbuffer_remove(buf, &val, sizeof(uint32_t));
return ntohl(val);
}
static uint64_t evbuffer_read_ntoh_64(struct evbuffer* buf)
{
auto val = uint64_t{};
evbuffer_remove(buf, &val, sizeof(uint64_t));
return tr_ntohll(val);
}
/****
*****
****/
using tau_connection_t = uint64_t;
static auto constexpr TauConnectionTtlSecs = int{ 60 };
using tau_transaction_t = uint32_t;
static tau_transaction_t tau_transaction_new(void)
{
auto tmp = tau_transaction_t{};
tr_rand_buffer(&tmp, sizeof(tau_transaction_t));
return tmp;
}
/* used in the "action" field of a request */
enum tau_action_t
{
TAU_ACTION_CONNECT = 0,
TAU_ACTION_ANNOUNCE = 1,
TAU_ACTION_SCRAPE = 2,
TAU_ACTION_ERROR = 3
};
static bool is_tau_response_message(tau_action_t action, size_t msglen)
{
if (action == TAU_ACTION_CONNECT)
{
return msglen == 16;
}
if (action == TAU_ACTION_ANNOUNCE)
{
return msglen >= 20;
}
if (action == TAU_ACTION_SCRAPE)
{
return msglen >= 20;
}
if (action == TAU_ACTION_ERROR)
{
return msglen >= 8;
}
return false;
}
static auto constexpr TauRequestTtl = int{ 60 };
/****
*****
***** SCRAPE
*****
****/
struct tau_scrape_request
{
std::vector<uint8_t> payload;
time_t sent_at;
time_t created_at;
tau_transaction_t transaction_id;
tr_scrape_response response;
tr_scrape_response_func callback;
void* user_data;
};
static struct tau_scrape_request* tau_scrape_request_new(
tr_scrape_request const* in,
tr_scrape_response_func callback,
void* user_data)
{
tau_transaction_t const transaction_id = tau_transaction_new();
/* build the payload */
auto* buf = evbuffer_new();
evbuffer_add_hton_32(buf, TAU_ACTION_SCRAPE);
evbuffer_add_hton_32(buf, transaction_id);
for (int i = 0; i < in->info_hash_count; ++i)
{
evbuffer_add(buf, std::data(in->info_hash[i]), std::size(in->info_hash[i]));
}
auto const* const payload_begin = evbuffer_pullup(buf, -1);
auto const* const payload_end = payload_begin + evbuffer_get_length(buf);
/* build the tau_scrape_request */
auto* req = new tau_scrape_request{};
req->callback = callback;
req->created_at = tr_time();
req->transaction_id = transaction_id;
req->callback = callback;
req->user_data = user_data;
req->response.scrape_url = in->scrape_url;
req->response.row_count = in->info_hash_count;
req->payload.assign(payload_begin, payload_end);
for (int i = 0; i < req->response.row_count; ++i)
{
req->response.rows[i].seeders = -1;
req->response.rows[i].leechers = -1;
req->response.rows[i].downloads = -1;
req->response.rows[i].info_hash = in->info_hash[i];
}
/* cleanup */
evbuffer_free(buf);
return req;
}
static void tau_scrape_request_free(struct tau_scrape_request* req)
{
delete req;
}
static void tau_scrape_request_finished(struct tau_scrape_request const* request)
{
if (request->callback != nullptr)
{
request->callback(&request->response, request->user_data);
}
}
static void tau_scrape_request_fail(
struct tau_scrape_request* request,
bool did_connect,
bool did_timeout,
std::string_view errmsg)
{
request->response.did_connect = did_connect;
request->response.did_timeout = did_timeout;
request->response.errmsg = errmsg;
tau_scrape_request_finished(request);
}
static void on_scrape_response(struct tau_scrape_request* request, tau_action_t action, struct evbuffer* buf)
{
request->response.did_connect = true;
request->response.did_timeout = false;
if (action == TAU_ACTION_SCRAPE)
{
for (int i = 0; i < request->response.row_count; ++i)
{
if (evbuffer_get_length(buf) < sizeof(uint32_t) * 3)
{
break;
}
struct tr_scrape_response_row& row = request->response.rows[i];
row.seeders = evbuffer_read_ntoh_32(buf);
row.downloads = evbuffer_read_ntoh_32(buf);
row.leechers = evbuffer_read_ntoh_32(buf);
}
tau_scrape_request_finished(request);
}
else
{
size_t const buflen = evbuffer_get_length(buf);
auto const errmsg = action == TAU_ACTION_ERROR && buflen > 0 ?
std::string_view{ reinterpret_cast<char const*>(evbuffer_pullup(buf, -1)), buflen } :
_("Unknown error");
tau_scrape_request_fail(request, true, false, errmsg);
}
}
/****
*****
***** ANNOUNCE
*****
****/
struct tau_announce_request
{
std::vector<uint8_t> payload;
time_t created_at;
time_t sent_at;
tau_transaction_t transaction_id;
tr_announce_response response;
tr_announce_response_func callback;
void* user_data;
};
enum tau_announce_event
{
/* used in the "event" field of an announce request */
TAU_ANNOUNCE_EVENT_NONE = 0,
TAU_ANNOUNCE_EVENT_COMPLETED = 1,
TAU_ANNOUNCE_EVENT_STARTED = 2,
TAU_ANNOUNCE_EVENT_STOPPED = 3
};
static tau_announce_event get_tau_announce_event(tr_announce_event e)
{
switch (e)
{
case TR_ANNOUNCE_EVENT_COMPLETED:
return TAU_ANNOUNCE_EVENT_COMPLETED;
case TR_ANNOUNCE_EVENT_STARTED:
return TAU_ANNOUNCE_EVENT_STARTED;
case TR_ANNOUNCE_EVENT_STOPPED:
return TAU_ANNOUNCE_EVENT_STOPPED;
default:
return TAU_ANNOUNCE_EVENT_NONE;
}
}
static struct tau_announce_request* tau_announce_request_new(
tr_announce_request const* in,
tr_announce_response_func callback,
void* user_data)
{
tau_transaction_t const transaction_id = tau_transaction_new();
/* build the payload */
auto* buf = evbuffer_new();
evbuffer_add_hton_32(buf, TAU_ACTION_ANNOUNCE);
evbuffer_add_hton_32(buf, transaction_id);
evbuffer_add(buf, std::data(in->info_hash), std::size(in->info_hash));
evbuffer_add(buf, std::data(in->peer_id), std::size(in->peer_id));
evbuffer_add_hton_64(buf, in->down);
evbuffer_add_hton_64(buf, in->leftUntilComplete);
evbuffer_add_hton_64(buf, in->up);
evbuffer_add_hton_32(buf, get_tau_announce_event(in->event));
evbuffer_add_hton_32(buf, 0);
evbuffer_add_hton_32(buf, in->key);
evbuffer_add_hton_32(buf, in->numwant);
evbuffer_add_hton_16(buf, in->port);
auto const* const payload_begin = evbuffer_pullup(buf, -1);
auto const* const payload_end = payload_begin + evbuffer_get_length(buf);
/* build the tau_announce_request */
auto* req = new tau_announce_request{};
req->created_at = tr_time();
req->transaction_id = transaction_id;
req->callback = callback;
req->user_data = user_data;
req->payload.assign(payload_begin, payload_end);
req->response.seeders = -1;
req->response.leechers = -1;
req->response.downloads = -1;
req->response.info_hash = in->info_hash;
evbuffer_free(buf);
return req;
}
static void tau_announce_request_free(struct tau_announce_request* req)
{
tr_free(req->response.tracker_id_str);
tr_free(req->response.pex6);
tr_free(req->response.pex);
delete req;
}
static void tau_announce_request_finished(struct tau_announce_request const* request)
{
if (request->callback != nullptr)
{
request->callback(&request->response, request->user_data);
}
}
static void tau_announce_request_fail(
struct tau_announce_request* request,
bool did_connect,
bool did_timeout,
std::string_view errmsg)
{
request->response.did_connect = did_connect;
request->response.did_timeout = did_timeout;
request->response.errmsg = errmsg;
tau_announce_request_finished(request);
}
static void on_announce_response(struct tau_announce_request* request, tau_action_t action, struct evbuffer* buf)
{
size_t const buflen = evbuffer_get_length(buf);
request->response.did_connect = true;
request->response.did_timeout = false;
if (action == TAU_ACTION_ANNOUNCE && buflen >= 3 * sizeof(uint32_t))
{
tr_announce_response* resp = &request->response;
resp->interval = evbuffer_read_ntoh_32(buf);
resp->leechers = evbuffer_read_ntoh_32(buf);
resp->seeders = evbuffer_read_ntoh_32(buf);
resp->pex = tr_peerMgrCompactToPex(
evbuffer_pullup(buf, -1),
evbuffer_get_length(buf),
nullptr,
0,
&request->response.pex_count);
tau_announce_request_finished(request);
}
else
{
auto const errmsg = action == TAU_ACTION_ERROR && buflen > 0 ?
std::string_view{ reinterpret_cast<char const*>(evbuffer_pullup(buf, -1)), buflen } :
_("Unknown error");
tau_announce_request_fail(request, true, false, errmsg);
}
}
/****
*****
***** TRACKERS
*****
****/
struct tau_tracker
{
tr_session* const session;
tr_interned_string const key;
tr_interned_string const host;
int const port;
struct evdns_getaddrinfo_request* dns_request = nullptr;
struct evutil_addrinfo* addr = nullptr;
time_t addr_expiration_time = 0;
time_t connecting_at = 0;
time_t connection_expiration_time = 0;
tau_connection_t connection_id = 0;
tau_transaction_t connection_transaction_id = 0;
time_t close_at = 0;
tr_ptrArray announces = {};
tr_ptrArray scrapes = {};
tau_tracker(tr_session* session_in, tr_interned_string key_in, tr_interned_string host_in, int port_in)
: session{ session_in }
, key{ key_in }
, host{ host_in }
, port{ port_in }
{
}
};
static void tau_tracker_upkeep(struct tau_tracker*);
static void tau_tracker_free(struct tau_tracker* t)
{
TR_ASSERT(t->dns_request == nullptr);
if (t->addr != nullptr)
{
evutil_freeaddrinfo(t->addr);
}
tr_ptrArrayDestruct(&t->announces, (PtrArrayForeachFunc)tau_announce_request_free);
tr_ptrArrayDestruct(&t->scrapes, (PtrArrayForeachFunc)tau_scrape_request_free);
delete t;
}
static void tau_tracker_fail_all(struct tau_tracker* tracker, bool did_connect, bool did_timeout, std::string_view errmsg)
{
/* fail all the scrapes */
tr_ptrArray* reqs = &tracker->scrapes;
for (int i = 0, n = tr_ptrArraySize(reqs); i < n; ++i)
{
auto* req = static_cast<struct tau_scrape_request*>(tr_ptrArrayNth(reqs, i));
tau_scrape_request_fail(req, did_connect, did_timeout, errmsg);
}
tr_ptrArrayDestruct(reqs, (PtrArrayForeachFunc)tau_scrape_request_free);
*reqs = {};
/* fail all the announces */
reqs = &tracker->announces;
for (int i = 0, n = tr_ptrArraySize(reqs); i < n; ++i)
{
auto* req = static_cast<struct tau_announce_request*>(tr_ptrArrayNth(reqs, i));
tau_announce_request_fail(req, did_connect, did_timeout, errmsg);
}
tr_ptrArrayDestruct(reqs, (PtrArrayForeachFunc)tau_announce_request_free);
*reqs = {};
}
static void tau_tracker_on_dns(int errcode, struct evutil_addrinfo* addr, void* vtracker)
{
auto* tracker = static_cast<struct tau_tracker*>(vtracker);
tracker->dns_request = nullptr;
if (errcode != 0)
{
auto const errmsg = tr_strvJoin("DNS Lookup failed: "sv, evutil_gai_strerror(errcode));
dbgmsg(tracker->key, "%s", errmsg.c_str());
tau_tracker_fail_all(tracker, false, false, errmsg.c_str());
}
else
{
dbgmsg(tracker->key, "DNS lookup succeeded");
tracker->addr = addr;
tracker->addr_expiration_time = tr_time() + 60 * 60; /* one hour */
tau_tracker_upkeep(tracker);
}
}
static void tau_tracker_send_request(struct tau_tracker* tracker, void const* payload, size_t payload_len)
{
struct evbuffer* buf = evbuffer_new();
dbgmsg(tracker->key, "sending request w/connection id %" PRIu64 "\n", tracker->connection_id);
evbuffer_add_hton_64(buf, tracker->connection_id);
evbuffer_add_reference(buf, payload, payload_len, nullptr, nullptr);
(void)tau_sendto(tracker->session, tracker->addr, tracker->port, evbuffer_pullup(buf, -1), evbuffer_get_length(buf));
evbuffer_free(buf);
}
static void tau_tracker_send_reqs(struct tau_tracker* tracker)
{
TR_ASSERT(tracker->dns_request == nullptr);
TR_ASSERT(tracker->connecting_at == 0);
TR_ASSERT(tracker->addr != nullptr);
time_t const now = tr_time();
TR_ASSERT(tracker->connection_expiration_time > now);
tr_ptrArray* reqs = &tracker->announces;
for (int i = 0, n = tr_ptrArraySize(reqs); i < n; ++i)
{
auto* req = static_cast<struct tau_announce_request*>(tr_ptrArrayNth(reqs, i));
if (req->sent_at == 0)
{
dbgmsg(tracker->key, "sending announce req %p", (void*)req);
req->sent_at = now;
tau_tracker_send_request(tracker, std::data(req->payload), std::size(req->payload));
if (req->callback == nullptr)
{
tau_announce_request_free(req);
tr_ptrArrayRemove(reqs, i);
--i;
--n;
}
}
}
reqs = &tracker->scrapes;
for (int i = 0, n = tr_ptrArraySize(reqs); i < n; ++i)
{
auto* req = static_cast<struct tau_scrape_request*>(tr_ptrArrayNth(reqs, i));
if (req->sent_at == 0)
{
dbgmsg(tracker->key, "sending scrape req %p", (void*)req);
req->sent_at = now;
tau_tracker_send_request(tracker, std::data(req->payload), std::size(req->payload));
if (req->callback == nullptr)
{
tau_scrape_request_free(req);
tr_ptrArrayRemove(reqs, i);
--i;
--n;
}
}
}
}
static void on_tracker_connection_response(struct tau_tracker* tracker, tau_action_t action, struct evbuffer* buf)
{
time_t const now = tr_time();
tracker->connecting_at = 0;
tracker->connection_transaction_id = 0;
if (action == TAU_ACTION_CONNECT)
{
tracker->connection_id = evbuffer_read_ntoh_64(buf);
tracker->connection_expiration_time = now + TauConnectionTtlSecs;
dbgmsg(tracker->key, "Got a new connection ID from tracker: %" PRIu64, tracker->connection_id);
}
else
{
size_t const buflen = buf != nullptr ? evbuffer_get_length(buf) : 0;
auto const errmsg = action == TAU_ACTION_ERROR && buflen > 0 ?
std::string_view{ reinterpret_cast<char const*>(evbuffer_pullup(buf, -1)), buflen } :
std::string_view{ _("Connection failed") };
dbgmsg(tracker->key, "%" TR_PRIsv, TR_PRIsv_ARG(errmsg));
tau_tracker_fail_all(tracker, true, false, errmsg);
}
tau_tracker_upkeep(tracker);
}
static void tau_tracker_timeout_reqs(struct tau_tracker* tracker)
{
time_t const now = time(nullptr);
bool const cancel_all = tracker->close_at != 0 && (tracker->close_at <= now);
if (tracker->connecting_at != 0 && tracker->connecting_at + TauRequestTtl < now)
{
on_tracker_connection_response(tracker, TAU_ACTION_ERROR, nullptr);
}
tr_ptrArray* reqs = &tracker->announces;
for (int i = 0, n = tr_ptrArraySize(reqs); i < n; ++i)
{
auto* req = static_cast<struct tau_announce_request*>(tr_ptrArrayNth(reqs, i));
if (cancel_all || req->created_at + TauRequestTtl < now)
{
dbgmsg(tracker->key, "timeout announce req %p", (void*)req);
tau_announce_request_fail(req, false, true, "");
tau_announce_request_free(req);
tr_ptrArrayRemove(reqs, i);
--i;
--n;
}
}
reqs = &tracker->scrapes;
for (int i = 0, n = tr_ptrArraySize(reqs); i < n; ++i)
{
auto* const req = static_cast<struct tau_scrape_request*>(tr_ptrArrayNth(reqs, i));
if (cancel_all || req->created_at + TauRequestTtl < now)
{
dbgmsg(tracker->key, "timeout scrape req %p", (void*)req);
tau_scrape_request_fail(req, false, true, "");
tau_scrape_request_free(req);
tr_ptrArrayRemove(reqs, i);
--i;
--n;
}
}
}
static bool tau_tracker_is_idle(struct tau_tracker const* tracker)
{
return tr_ptrArrayEmpty(&tracker->announces) && tr_ptrArrayEmpty(&tracker->scrapes) && tracker->dns_request == nullptr;
}
static void tau_tracker_upkeep_ex(struct tau_tracker* tracker, bool timeout_reqs)
{
time_t const now = tr_time();
bool const closing = tracker->close_at != 0;
/* if the address info is too old, expire it */
if (tracker->addr != nullptr && (closing || tracker->addr_expiration_time <= now))
{
dbgmsg(tracker->host, "Expiring old DNS result");
evutil_freeaddrinfo(tracker->addr);
tracker->addr = nullptr;
}
/* are there any requests pending? */
if (tau_tracker_is_idle(tracker))
{
return;
}
/* if we don't have an address yet, try & get one now. */
if (!closing && tracker->addr == nullptr && tracker->dns_request == nullptr)
{
struct evutil_addrinfo hints;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_DGRAM;
hints.ai_protocol = IPPROTO_UDP;
dbgmsg(tracker->host, "Trying a new DNS lookup");
tracker->dns_request = evdns_getaddrinfo(
tracker->session->evdns_base,
tracker->host.c_str(),
nullptr,
&hints,
tau_tracker_on_dns,
tracker);
return;
}
dbgmsg(
tracker->key,
"addr %p -- connected %d (%zu %zu) -- connecting_at %zu",
(void*)tracker->addr,
(int)(tracker->connection_expiration_time > now),
(size_t)tracker->connection_expiration_time,
(size_t)now,
(size_t)tracker->connecting_at);
/* also need a valid connection ID... */
if (tracker->addr != nullptr && tracker->connection_expiration_time <= now && tracker->connecting_at == 0)
{
struct evbuffer* buf = evbuffer_new();
tracker->connecting_at = now;
tracker->connection_transaction_id = tau_transaction_new();
dbgmsg(tracker->key, "Trying to connect. Transaction ID is %u", tracker->connection_transaction_id);
evbuffer_add_hton_64(buf, 0x41727101980LL);
evbuffer_add_hton_32(buf, TAU_ACTION_CONNECT);
evbuffer_add_hton_32(buf, tracker->connection_transaction_id);
(void)tau_sendto(tracker->session, tracker->addr, tracker->port, evbuffer_pullup(buf, -1), evbuffer_get_length(buf));
evbuffer_free(buf);
return;
}
if (timeout_reqs)
{
tau_tracker_timeout_reqs(tracker);
}
if (tracker->addr != nullptr && tracker->connection_expiration_time > now)
{
tau_tracker_send_reqs(tracker);
}
}
static void tau_tracker_upkeep(struct tau_tracker* tracker)
{
tau_tracker_upkeep_ex(tracker, true);
}
/****
*****
***** SESSION
*****
****/
struct tr_announcer_udp
{
/* tau_tracker */
tr_ptrArray trackers;
tr_session* session;
};
static struct tr_announcer_udp* announcer_udp_get(tr_session* session)
{
if (session->announcer_udp != nullptr)
{
return session->announcer_udp;
}
auto* const tau = tr_new0(tr_announcer_udp, 1);
tau->trackers = {};
tau->session = session;
session->announcer_udp = tau;
return tau;
}
/* Finds the tau_tracker struct that corresponds to this url.
If it doesn't exist yet, create one. */
static tau_tracker* tau_session_get_tracker(tr_announcer_udp* tau, tr_interned_string announce_url)
{
// build a lookup key for this tracker
auto const announce_sv = announce_url.sv();
auto parsed = tr_urlParseTracker(announce_sv);
TR_ASSERT(parsed);
if (!parsed)
{
return nullptr;
}
// see if we already have it
// TODO: replace tr_ptrArray
auto const key = tr_announcerGetKey(*parsed);
for (int i = 0, n = tr_ptrArraySize(&tau->trackers); i < n; ++i)
{
auto* tmp = static_cast<struct tau_tracker*>(tr_ptrArrayNth(&tau->trackers, i));
if (tmp->key == key)
{
return tmp;
}
}
// we don't have it -- build a new one
auto* const tracker = new tau_tracker{ tau->session, key, tr_interned_string(parsed->host), parsed->port };
tr_ptrArrayAppend(&tau->trackers, tracker);
dbgmsg(tracker->key, "New tau_tracker created");
return tracker;
}
/****
*****
***** PUBLIC API
*****
****/
void tr_tracker_udp_upkeep(tr_session* session)
{
struct tr_announcer_udp* tau = session->announcer_udp;
if (tau != nullptr)
{
tr_ptrArrayForeach(&tau->trackers, (PtrArrayForeachFunc)tau_tracker_upkeep);
}
}
bool tr_tracker_udp_is_idle(tr_session const* session)
{
struct tr_announcer_udp* tau = session->announcer_udp;
if (tau != nullptr)
{
for (int i = 0, n = tr_ptrArraySize(&tau->trackers); i < n; ++i)
{
auto const* tracker = static_cast<struct tau_tracker const*>(tr_ptrArrayNth(&tau->trackers, i));
if (!tau_tracker_is_idle(tracker))
{
return false;
}
}
}
return true;
}
/* drop dead now. */
void tr_tracker_udp_close(tr_session* session)
{
struct tr_announcer_udp* tau = session->announcer_udp;
if (tau != nullptr)
{
session->announcer_udp = nullptr;
tr_ptrArrayDestruct(&tau->trackers, (PtrArrayForeachFunc)tau_tracker_free);
tr_free(tau);
}
}
/* start shutting down.
This doesn't destroy everything if there are requests,
but sets a deadline on how much longer to wait for the remaining ones */
void tr_tracker_udp_start_shutdown(tr_session* session)
{
time_t const now = time(nullptr);
struct tr_announcer_udp* tau = session->announcer_udp;
if (tau != nullptr)
{
for (int i = 0, n = tr_ptrArraySize(&tau->trackers); i < n; ++i)
{
auto* tracker = static_cast<struct tau_tracker*>(tr_ptrArrayNth(&tau->trackers, i));
if (tracker->dns_request != nullptr)
{
evdns_getaddrinfo_cancel(tracker->dns_request);
}
tracker->close_at = now + 3;
tau_tracker_upkeep(tracker);
}
}
}
/* @brief process an incoming udp message if it's a tracker response.
* @return true if msg was a tracker response; false otherwise */
bool tau_handle_message(tr_session* session, uint8_t const* msg, size_t msglen)
{
if (session == nullptr || session->announcer_udp == nullptr)
{
return false;
}
if (msglen < sizeof(uint32_t) * 2)
{
return false;
}
/* extract the action_id and see if it makes sense */
struct evbuffer* const buf = evbuffer_new();
evbuffer_add_reference(buf, msg, msglen, nullptr, nullptr);
auto const action_id = tau_action_t(evbuffer_read_ntoh_32(buf));
if (!is_tau_response_message(action_id, msglen))
{
evbuffer_free(buf);
return false;
}
/* extract the transaction_id and look for a match */
struct tr_announcer_udp* const tau = session->announcer_udp;
tau_transaction_t const transaction_id = evbuffer_read_ntoh_32(buf);
for (int i = 0, n = tr_ptrArraySize(&tau->trackers); i < n; ++i)
{
auto* tracker = static_cast<struct tau_tracker*>(tr_ptrArrayNth(&tau->trackers, i));
/* is it a connection response? */
if (tracker->connecting_at != 0 && transaction_id == tracker->connection_transaction_id)
{
dbgmsg(tracker->key, "%" PRIu32 " is my connection request!", transaction_id);
on_tracker_connection_response(tracker, action_id, buf);
evbuffer_free(buf);
return true;
}
/* is it a response to one of this tracker's announces? */
tr_ptrArray* reqs = &tracker->announces;
for (int j = 0, jn = tr_ptrArraySize(reqs); j < jn; ++j)
{
auto* req = static_cast<struct tau_announce_request*>(tr_ptrArrayNth(reqs, j));
if (req->sent_at != 0 && transaction_id == req->transaction_id)
{
dbgmsg(tracker->key, "%" PRIu32 " is an announce request!", transaction_id);
tr_ptrArrayRemove(reqs, j);
on_announce_response(req, action_id, buf);
tau_announce_request_free(req);
evbuffer_free(buf);
return true;
}
}
/* is it a response to one of this tracker's scrapes? */
reqs = &tracker->scrapes;
for (int j = 0, jn = tr_ptrArraySize(reqs); j < jn; ++j)
{
auto* const req = static_cast<struct tau_scrape_request*>(tr_ptrArrayNth(reqs, j));
if (req->sent_at != 0 && transaction_id == req->transaction_id)
{
dbgmsg(tracker->key, "%" PRIu32 " is a scrape request!", transaction_id);
tr_ptrArrayRemove(reqs, j);
on_scrape_response(req, action_id, buf);
tau_scrape_request_free(req);
evbuffer_free(buf);
return true;
}
}
}
/* no match... */
evbuffer_free(buf);
return false;
}
void tr_tracker_udp_announce(
tr_session* session,
tr_announce_request const* request,
tr_announce_response_func response_func,
void* user_data)
{
tr_announcer_udp* tau = announcer_udp_get(session);
tau_tracker* tracker = tau_session_get_tracker(tau, request->announce_url);
if (tracker == nullptr)
{
return;
}
tau_announce_request* r = tau_announce_request_new(request, response_func, user_data);
tr_ptrArrayAppend(&tracker->announces, r);
tau_tracker_upkeep_ex(tracker, false);
}
void tr_tracker_udp_scrape(
tr_session* session,
tr_scrape_request const* request,
tr_scrape_response_func response_func,
void* user_data)
{
tr_announcer_udp* tau = announcer_udp_get(session);
tau_tracker* tracker = tau_session_get_tracker(tau, request->scrape_url);
if (tracker == nullptr)
{
return;
}
tau_scrape_request* r = tau_scrape_request_new(request, response_func, user_data);
tr_ptrArrayAppend(&tracker->scrapes, r);
tau_tracker_upkeep_ex(tracker, false);
}
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