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transmission/libtransmission/announcer-udp.c

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/*
* This file Copyright (C) Mnemosyne LLC
*
* This file is licensed by the GPL version 2. Works owned by the
* Transmission project are granted a special exemption to clause 2(b)
* so that the bulk of its code can remain under the MIT license.
* This exemption does not extend to derived works not owned by
* the Transmission project.
*
* $Id$
*/
#define __LIBTRANSMISSION_ANNOUNCER_MODULE___
#include <event2/buffer.h>
#include <event2/dns.h>
#include <event2/util.h>
#include "transmission.h"
#include "announcer-common.h"
#include "crypto.h"
#include "peer-io.h"
#include "peer-mgr.h" /* tr_peerMgrCompactToPex() */
#include "ptrarray.h"
#include "tr-udp.h"
#include "utils.h"
#define dbgmsg( name, ... ) \
if( tr_deepLoggingIsActive( ) ) do { \
tr_deepLog( __FILE__, __LINE__, name, __VA_ARGS__ ); \
} while( 0 )
/****
*****
****/
static void
tau_sockaddr_setport( struct sockaddr * sa, tr_port port )
{
if( sa->sa_family == AF_INET )
((struct sockaddr_in *)sa)->sin_port = htons(port);
else if (sa->sa_family == AF_INET6)
((struct sockaddr_in6 *)sa)->sin6_port = htons(port);
}
static int
tau_sendto( tr_session * session,
struct evutil_addrinfo * ai, tr_port port,
const void * buf, size_t buflen )
{
int sockfd;
tau_sockaddr_setport( ai->ai_addr, port );
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 = -1;
if( sockfd < 0 ) {
errno = EAFNOSUPPORT;
return -1;
}
return sendto( sockfd, buf, buflen, 0, ai->ai_addr, ai->ai_addrlen );
}
/****
*****
****/
static uint32_t
evbuffer_read_ntoh_32( struct evbuffer * buf )
{
uint32_t val;
evbuffer_remove( buf, &val, sizeof( uint32_t ) );
return ntohl( val );
}
static uint64_t
evbuffer_read_ntoh_64( struct evbuffer * buf )
{
uint64_t val;
evbuffer_remove( buf, &val, sizeof( uint64_t ) );
return tr_ntohll( val );
}
/****
*****
****/
typedef uint64_t tau_connection_t;
enum
{
TAU_CONNECTION_TTL_SECS = 60
};
typedef uint32_t tau_transaction_t;
static tau_transaction_t
tau_transaction_new( void )
{
tau_transaction_t tmp;
tr_cryptoRandBuf( &tmp, sizeof( tau_transaction_t ) );
return tmp;
}
/* used in the "action" field of a request */
typedef enum
{
TAU_ACTION_CONNECT = 0,
TAU_ACTION_ANNOUNCE = 1,
TAU_ACTION_SCRAPE = 2,
TAU_ACTION_ERROR = 3,
TAU_ACTION_MAX = 3
}
tau_action_t;
enum
{
TAU_REQUEST_TTL = 120
};
/****
*****
***** SCRAPE
*****
****/
struct tau_scrape_request
{
void * payload;
size_t payload_len;
time_t sent_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( const tr_scrape_request * in,
tr_scrape_response_func callback,
void * user_data )
{
int i;
struct evbuffer * buf;
struct tau_scrape_request * req = tr_new0( struct tau_scrape_request, 1 );
req->transaction_id = tau_transaction_new( );
req->callback = callback;
req->user_data = user_data;
req->response.url = tr_strdup( in->url );
req->response.row_count = in->info_hash_count;
for( i=0; i<req->response.row_count; ++i )
memcpy( req->response.rows[i].info_hash,
in->info_hash[i], SHA_DIGEST_LENGTH );
/* build the payload */
buf = evbuffer_new( );
evbuffer_add_hton_32( buf, TAU_ACTION_SCRAPE );
evbuffer_add_hton_32( buf, req->transaction_id );
for( i=0; i<in->info_hash_count; ++i )
evbuffer_add( buf, in->info_hash[i], SHA_DIGEST_LENGTH );
req->payload_len = evbuffer_get_length( buf );
req->payload = tr_memdup( evbuffer_pullup( buf, -1 ), req->payload_len );
evbuffer_free( buf );
return req;
}
static void
tau_scrape_request_free( struct tau_scrape_request * req )
{
tr_free( req->payload );
tr_free( req->response.errmsg );
tr_free( req->response.url );
tr_free( req );
}
static void
tau_scrape_request_finished( tr_session * session,
const struct tau_scrape_request * request )
{
if( request->callback != NULL )
request->callback( session, &request->response, request->user_data );
}
static void
tau_scrape_request_fail( tr_session * session,
struct tau_scrape_request * request,
tr_bool did_connect,
tr_bool did_timeout,
const char * errmsg )
{
request->response.did_connect = did_connect;
request->response.did_timeout = did_timeout;
request->response.errmsg = tr_strdup( errmsg );
tau_scrape_request_finished( session, request );
}
static void
on_scrape_response( tr_session * session,
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 )
{
int i;
for( i=0; i<request->response.row_count; ++i )
{
struct tr_scrape_response_row * row;
if( evbuffer_get_length( buf ) < ( sizeof( uint32_t ) * 3 ) )
break;
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( session, request );
}
else
{
assert( action == TAU_ACTION_ERROR );
tau_scrape_request_fail( session, request,
TRUE, FALSE, _( "Unknown error" ) );
}
}
/****
*****
***** ANNOUNCE
*****
****/
struct tau_announce_request
{
void * payload;
size_t payload_len;
time_t sent_at;
tau_transaction_t transaction_id;
tr_announce_response response;
tr_announce_response_func * callback;
void * user_data;
};
typedef enum
{
/* 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
}
tau_announce_event;
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( const tr_announce_request * in,
tr_announce_response_func callback,
void * user_data )
{
struct evbuffer * buf;
struct tau_announce_request * r = tr_new0( struct tau_announce_request, 1 );
r->transaction_id = tau_transaction_new( );
r->callback = callback;
r->user_data = user_data;
memcpy( r->response.info_hash, in->info_hash, SHA_DIGEST_LENGTH );
/* build the announce payload */
buf = evbuffer_new( );
evbuffer_add_hton_32( buf, TAU_ACTION_ANNOUNCE );
evbuffer_add_hton_32( buf, r->transaction_id );
evbuffer_add ( buf, in->info_hash, SHA_DIGEST_LENGTH );
evbuffer_add ( buf, in->peer_id, PEER_ID_LEN );
evbuffer_add_hton_64( buf, in->down );
evbuffer_add_hton_64( buf, in->left );
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 );
r->payload_len = evbuffer_get_length( buf );
r->payload = tr_memdup( evbuffer_pullup( buf, -1 ), r->payload_len );
evbuffer_free( buf );
return r;
}
static void
tau_announce_request_free( struct tau_announce_request * req )
{
tr_free( req->payload );
tr_free( req->response.tracker_id_str );
tr_free( req->response.warning );
tr_free( req->response.errmsg );
tr_free( req->response.pex6 );
tr_free( req->response.pex );
tr_free( req );
}
static void
tau_announce_request_finished( tr_session * session,
const struct tau_announce_request * request )
{
if( request->callback != NULL )
request->callback( session, &request->response, request->user_data );
}
static void
tau_announce_request_fail( tr_session * session,
struct tau_announce_request * request,
tr_bool did_connect,
tr_bool did_timeout,
const char * errmsg )
{
request->response.did_connect = did_connect;
request->response.did_timeout = did_timeout;
request->response.errmsg = tr_strdup( errmsg );
tau_announce_request_finished( session, request );
}
static void
on_announce_response( tr_session * session,
struct tau_announce_request * request,
tau_action_t action,
struct evbuffer * buf )
{
request->response.did_connect = TRUE;
request->response.did_timeout = FALSE;
if( ( action == TAU_ACTION_ANNOUNCE )
&& ( evbuffer_get_length( buf ) >= 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 ),
NULL, 0,
&request->response.pex_count );
tau_announce_request_finished( session, request );
}
else
{
assert( action == TAU_ACTION_ERROR );
tau_announce_request_fail( session, request,
TRUE, FALSE, _( "Unknown error" ) );
}
}
/****
*****
***** TRACKERS
*****
****/
struct tau_tracker
{
tr_session * session;
char * key;
char * host;
int port;
tr_bool is_asking_dns;
struct evutil_addrinfo * addr;
time_t addr_expiration_time;
tr_bool is_connecting;
time_t connection_expiration_time;
tau_connection_t connection_id;
tau_transaction_t connection_transaction_id;
tr_ptrArray announces;
tr_ptrArray scrapes;
};
static void tau_tracker_upkeep( struct tau_tracker * );
#if 0
static void
tau_tracker_free( struct tau_tracker * t )
{
if( t->addr )
evutil_freeaddrinfo( t->addr );
tr_ptrArrayDestruct( &t->announces, (PtrArrayForeachFunc)tau_announce_request_free );
tr_ptrArrayDestruct( &t->scrapes, (PtrArrayForeachFunc)tau_scrape_request_free );
tr_free( t->host );
tr_free( t->key );
tr_free( t );
}
#endif
static void
tau_tracker_fail_all( struct tau_tracker * tracker,
tr_bool did_connect,
tr_bool did_timeout,
const char * errmsg )
{
int i;
int n;
tr_ptrArray * reqs;
/* fail all the scrapes */
reqs = &tracker->scrapes;
for( i=0, n=tr_ptrArraySize(reqs); i<n; ++i )
tau_scrape_request_fail( tracker->session, tr_ptrArrayNth( reqs, i ),
did_connect, did_timeout, errmsg );
tr_ptrArrayDestruct( reqs, (PtrArrayForeachFunc)tau_scrape_request_free );
*reqs = TR_PTR_ARRAY_INIT;
/* fail all the announces */
reqs = &tracker->announces;
for( i=0, n=tr_ptrArraySize(reqs); i<n; ++i )
tau_announce_request_fail( tracker->session, tr_ptrArrayNth( reqs, i ),
did_connect, did_timeout, errmsg );
tr_ptrArrayDestruct( reqs, (PtrArrayForeachFunc)tau_announce_request_free );
*reqs = TR_PTR_ARRAY_INIT;
}
static void
tau_tracker_on_dns( int errcode, struct evutil_addrinfo *addr, void * vtracker )
{
struct tau_tracker * tracker = vtracker;
tracker->is_asking_dns = FALSE;
if ( errcode )
{
char * errmsg = tr_strdup_printf( _( "DNS Lookup failed: %s" ),
evdns_err_to_string( errcode ) );
dbgmsg( tracker->key, "%s", errmsg );
tau_tracker_fail_all( tracker, FALSE, FALSE, errmsg );
tr_free( errmsg );
}
else
{
dbgmsg( tracker->key, "DNS lookup succeeded" );
tracker->addr = addr;
tracker->addr_expiration_time = tr_time() + 1800;
tau_tracker_upkeep( tracker );
}
}
static void
tau_tracker_send_request( struct tau_tracker * tracker,
const void * 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, NULL, NULL );
tau_sendto( tracker->session, tracker->addr, tracker->port,
evbuffer_pullup( buf, -1 ),
evbuffer_get_length( buf ) );
evbuffer_free( buf );
}
static void
tau_tracker_upkeep( struct tau_tracker * tracker )
{
int i;
int n;
tr_ptrArray * reqs;
const time_t now = tr_time( );
const tr_bool is_connected = tracker->connection_expiration_time > now;
/* if the address info is too old, expire it */
if( tracker->addr && ( tracker->addr_expiration_time <= now ) ) {
dbgmsg( tracker->host, "Expiring old DNS result" );
evutil_freeaddrinfo( tracker->addr );
tracker->addr = NULL;
}
/* are there any requests pending? */
if( tr_ptrArrayEmpty( &tracker->announces ) &&
tr_ptrArrayEmpty( &tracker->scrapes ) )
return;
/* if we don't have an address yet, try & get one now. */
if( !tracker->addr && !tracker->is_asking_dns )
{
struct evutil_addrinfo hints;
memset( &hints, 0, sizeof( hints ) );
hints.ai_family = AF_UNSPEC;
hints.ai_flags = EVUTIL_AI_CANONNAME;
hints.ai_socktype = SOCK_DGRAM;
hints.ai_protocol = IPPROTO_UDP;
tracker->is_asking_dns = TRUE;
dbgmsg( tracker->host, "Trying a new DNS lookup" );
evdns_getaddrinfo( tracker->session->evdns_base,
tracker->host, NULL, &hints,
tau_tracker_on_dns, tracker );
return;
}
/* also need a valid connection ID... */
if( !is_connected && !tracker->is_connecting && tracker->addr )
{
struct evbuffer * buf = evbuffer_new( );
tracker->is_connecting = TRUE;
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 );
tau_sendto( tracker->session, tracker->addr, tracker->port,
evbuffer_pullup( buf, -1 ),
evbuffer_get_length( buf ) );
evbuffer_free( buf );
return;
}
/* send the announce requests */
reqs = &tracker->announces;
for( i=0, n=tr_ptrArraySize(reqs); i<n; ++i )
{
struct tau_announce_request * req = tr_ptrArrayNth( reqs, i );
if( is_connected && !req->sent_at ) {
dbgmsg( tracker->key, "Sending an announce request" );
req->sent_at = now;
tau_tracker_send_request( tracker, req->payload, req->payload_len );
}
else if( req->sent_at && ( req->sent_at + TAU_REQUEST_TTL < now ) ) {
tau_announce_request_fail( tracker->session, req, FALSE, TRUE, NULL );
tau_announce_request_free( req );
tr_ptrArrayRemove( reqs, i );
--i;
--n;
}
}
/* send the scrape requests */
reqs = &tracker->scrapes;
for( i=0, n=tr_ptrArraySize(reqs); i<n; ++i )
{
struct tau_scrape_request * req = tr_ptrArrayNth( reqs, i );
if( is_connected && !req->sent_at ) {
dbgmsg( tracker->key, "Sending a scrape request" );
req->sent_at = now;
tau_tracker_send_request( tracker, req->payload, req->payload_len );
}
else if( req->sent_at && ( req->sent_at + TAU_REQUEST_TTL < now ) ) {
tau_scrape_request_fail( tracker->session, req, FALSE, TRUE, NULL );
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 )
{
const time_t now = tr_time( );
tracker->is_connecting = FALSE;
tracker->connection_transaction_id = 0;
if( action == TAU_ACTION_CONNECT )
{
tracker->connection_id = evbuffer_read_ntoh_64( buf );
tracker->connection_expiration_time = now + TAU_CONNECTION_TTL_SECS;
dbgmsg( tracker->key, "Got a new connection ID from tracker: %"PRIu64,
tracker->connection_id );
}
else
{
const char * errmsg = _( "Connection refused" );
assert( action == TAU_ACTION_ERROR );
dbgmsg( tracker->key, "%s", errmsg );
tau_tracker_fail_all( tracker, TRUE, FALSE, errmsg );
}
tau_tracker_upkeep( tracker );
}
/****
*****
***** SESSION
*****
****/
struct tr_announcer_udp
{
/* tau_tracker */
tr_ptrArray trackers;
tr_session * session;
};
static struct tr_announcer_udp*
announcer_udp_get( tr_session * session )
{
struct tr_announcer_udp * tau;
if( session->announcer_udp != NULL )
return session->announcer_udp;
tau = tr_new0( struct tr_announcer_udp, 1 );
tau->trackers = TR_PTR_ARRAY_INIT;
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 struct tau_tracker *
tau_session_get_tracker( struct tr_announcer_udp * tau, const char * url )
{
int i;
int n;
int port;
char * host;
char * key;
struct tau_tracker * tracker = NULL;
/* see if we've already got a tracker that matches this host + port */
tr_urlParse( url, -1, NULL, &host, &port, NULL );
key = tr_strdup_printf( "%s:%d", host, port );
for( i=0, n=tr_ptrArraySize( &tau->trackers ); !tracker && i<n; ++i ) {
struct tau_tracker * tmp = tr_ptrArrayNth( &tau->trackers, i );
if( !tr_strcmp0( tmp->key, key ) )
tracker = tmp;
}
/* if we don't have a match, build a new tracker */
if( tracker == NULL )
{
tracker = tr_new0( struct tau_tracker, 1 );
tracker->session = tau->session;
tracker->key = key;
tracker->host = host;
tracker->port = port;
tracker->scrapes = TR_PTR_ARRAY_INIT;
tracker->announces = TR_PTR_ARRAY_INIT;
tr_ptrArrayAppend( &tau->trackers, tracker );
dbgmsg( tracker->key, "New tau_tracker created" );
}
else
{
tr_free( key );
tr_free( host );
}
return tracker;
}
/****
*****
***** PUBLIC API
*****
****/
void
tr_tracker_udp_upkeep( tr_session * session )
{
struct tr_announcer_udp * tau = session->announcer_udp;
if( tau != NULL )
tr_ptrArrayForeach( &tau->trackers,
(PtrArrayForeachFunc)tau_tracker_upkeep );
}
tr_bool
tau_handle_message( tr_session * session,
const uint8_t * msg,
size_t msglen )
{
int i;
int n;
struct tr_announcer_udp * tau;
tau_action_t action_id;
tau_transaction_t transaction_id;
struct evbuffer * buf;
/*fprintf( stderr, "got an incoming udp message w/len %zu\n", msglen );*/
if( !session || !session->announcer_udp )
return FALSE;
if( msglen < (sizeof(uint32_t)*2) )
return FALSE;
/* extract the action_id and transaction_id */
buf = evbuffer_new( );
evbuffer_add_reference( buf, msg, msglen, NULL, NULL );
action_id = evbuffer_read_ntoh_32( buf );
transaction_id = evbuffer_read_ntoh_32( buf );
/*fprintf( stderr, "UDP got a transaction_id of %u...\n", transaction_id );*/
if( action_id > TAU_ACTION_MAX ) {
evbuffer_free( buf );
return FALSE;
}
/* look for a match to this transaction id */
tau = session->announcer_udp;
for( i=0, n=tr_ptrArraySize( &tau->trackers ); i<n; ++i )
{
int j, jn;
tr_ptrArray * reqs;
struct tau_tracker * tracker = tr_ptrArrayNth( &tau->trackers, i );
/* is it a connection response? */
if( tracker->is_connecting
&& ( transaction_id == tracker->connection_transaction_id ) )
{
dbgmsg( tracker->key, "%"PRIu32" matches 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? */
reqs = &tracker->announces;
for( j=0, jn=tr_ptrArraySize(reqs); j<jn; ++j ) {
struct tau_announce_request * req = tr_ptrArrayNth( reqs, j );
if( req->sent_at && ( transaction_id == req->transaction_id ) ) {
dbgmsg( tracker->key, "%"PRIu32" matches one of my announce requests!", transaction_id );
tr_ptrArrayRemove( reqs, j );
on_announce_response( session, 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( j=0, jn=tr_ptrArraySize(reqs); j<jn; ++j ) {
struct tau_scrape_request * req = tr_ptrArrayNth( reqs, j );
if( req->sent_at && ( transaction_id == req->transaction_id ) ) {
dbgmsg( tracker->key, "%"PRIu32" matches one of my scrape requests!", transaction_id );
tr_ptrArrayRemove( reqs, j );
on_scrape_response( session, 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,
const tr_announce_request * request,
tr_announce_response_func response_func,
void * user_data )
{
struct tr_announcer_udp * tau = announcer_udp_get( session );
struct tau_tracker * tracker = tau_session_get_tracker( tau, request->url );
struct tau_announce_request * r = tau_announce_request_new( request,
response_func,
user_data );
tr_ptrArrayAppend( &tracker->announces, r );
tau_tracker_upkeep( tracker );
}
void
tr_tracker_udp_scrape( tr_session * session,
const tr_scrape_request * request,
tr_scrape_response_func response_func,
void * user_data )
{
struct tr_announcer_udp * tau = announcer_udp_get( session );
struct tau_tracker * tracker = tau_session_get_tracker( tau, request->url );
struct tau_scrape_request * r = tau_scrape_request_new( request,
response_func,
user_data );
tr_ptrArrayAppend( &tracker->scrapes, r );
tau_tracker_upkeep( tracker );
}
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