int kad_export_nodes( IP addr_array[], size_t *num ) {
IP4 addr4[64];
IP6 addr6[64];
int num4;
int num6;
int i, count;
num6 = N_ELEMS( addr6 );
num4 = N_ELEMS( addr4 );
dht_lock();
dht_get_nodes( addr4, &num4, addr6, &num6 );
dht_unlock();
count = 0;
for( i = 0; i < num6 && count < *num; ++i, ++count ) {
memcpy( &addr_array[i], &addr6[i], sizeof(IP6) );
}
for( i = 0; i < num4 && count < *num; ++i, ++count ) {
memcpy( &addr_array[i], &addr4[i], sizeof(IP4) );
}
/* Store number of nodes we have actually found */
*num = count;
return 0;
}
void
tr_dhtUninit (tr_session *ss)
{
if (session != ss)
return;
tr_logAddNamedDbg ("DHT", "Uninitializing DHT");
if (dht_timer != NULL) {
event_free (dht_timer);
dht_timer = NULL;
}
/* Since we only save known good nodes, avoid erasing older data if we
don't know enough nodes. */
if ((tr_dhtStatus (ss, AF_INET, NULL) < TR_DHT_FIREWALLED) &&
(tr_dhtStatus (ss, AF_INET6, NULL) < TR_DHT_FIREWALLED)) {
tr_logAddNamedInfo ("DHT", "Not saving nodes, DHT not ready");
} else {
tr_variant benc;
struct sockaddr_in sins[300];
struct sockaddr_in6 sins6[300];
char compact[300 * 6], compact6[300 * 18];
char *dat_file;
int i, j, num = 300, num6 = 300;
int n = dht_get_nodes (sins, &num, sins6, &num6);
tr_logAddNamedInfo ("DHT", "Saving %d (%d + %d) nodes", n, num, num6);
j = 0;
for (i=0; i<num; ++i) {
memcpy (compact + j, &sins[i].sin_addr, 4);
memcpy (compact + j + 4, &sins[i].sin_port, 2);
j += 6;
}
j = 0;
for (i=0; i<num6; ++i) {
memcpy (compact6 + j, &sins6[i].sin6_addr, 16);
memcpy (compact6 + j + 16, &sins6[i].sin6_port, 2);
j += 18;
}
tr_variantInitDict (&benc, 3);
tr_variantDictAddRaw (&benc, TR_KEY_id, myid, 20);
if (num > 0)
tr_variantDictAddRaw (&benc, TR_KEY_nodes, compact, num * 6);
if (num6 > 0)
tr_variantDictAddRaw (&benc, TR_KEY_nodes6, compact6, num6 * 18);
dat_file = tr_buildPath (ss->configDir, "dht.dat", NULL);
tr_variantToFile (&benc, TR_VARIANT_FMT_BENC, dat_file);
tr_variantFree (&benc);
tr_free (dat_file);
}
dht_uninit ();
tr_logAddNamedDbg ("DHT", "Done uninitializing DHT");
session = NULL;
}
/* Export known nodes; the maximum is 200 nodes */
int kad_export_nodes( IP addr_array[], size_t *num ) {
IP4 *addr4;
IP6 *addr6;
int num4;
int num6;
int i;
if( gconf->af == AF_INET6 ) {
num6 = MIN(*num, 200);
addr6 = calloc( num6, sizeof(IP6) );
num4 = 0;
addr4 = NULL;
} else {
num6 = 0;
addr6 = NULL;
num4 = MIN(*num, 200);
addr4 = calloc( num4, sizeof(IP4) );
}
dht_lock();
dht_get_nodes( addr4, &num4, addr6, &num6 );
dht_unlock();
if( gconf->af == AF_INET6 ) {
for( i = 0; i < num6; ++i ) {
memcpy( &addr_array[i], &addr6[i], sizeof(IP6) );
}
free( addr6 );
} else {
for( i = 0; i < num4; ++i ) {
memcpy( &addr_array[i], &addr4[i], sizeof(IP4) );
}
free( addr4 );
}
/* Store number of nodes we have actually found */
*num = i;
return 0;
}
void
tr_dhtUninit(tr_session *ss)
{
if(session != ss)
return;
tr_ndbg( "DHT", "Uninitializing DHT" );
event_free( dht_event );
dht_event = NULL;
if( dht6_event ) {
event_free( dht6_event );
dht6_event = NULL;
}
/* Since we only save known good nodes, avoid erasing older data if we
don't know enough nodes. */
if(tr_dhtStatus(ss, AF_INET, NULL) < TR_DHT_FIREWALLED)
tr_ninf( "DHT", "Not saving nodes, DHT not ready" );
else {
tr_benc benc;
struct sockaddr_in sins[300];
struct sockaddr_in6 sins6[300];
char compact[300 * 6], compact6[300 * 18];
char *dat_file;
int i, j, num = 300, num6 = 300;
int n = dht_get_nodes(sins, &num, sins6, &num6);
tr_ninf( "DHT", "Saving %d (%d + %d) nodes", n, num, num6 );
j = 0;
for( i=0; i<num; ++i ) {
memcpy( compact + j, &sins[i].sin_addr, 4 );
memcpy( compact + j + 4, &sins[i].sin_port, 2 );
j += 6;
}
j = 0;
for( i=0; i<num6; ++i ) {
memcpy( compact6 + j, &sins6[i].sin6_addr, 16 );
memcpy( compact6 + j + 16, &sins6[i].sin6_port, 2 );
j += 18;
}
tr_bencInitDict( &benc, 3 );
tr_bencDictAddRaw( &benc, "id", myid, 20 );
if(num > 0)
tr_bencDictAddRaw( &benc, "nodes", compact, num * 6 );
if(num6 > 0)
tr_bencDictAddRaw( &benc, "nodes6", compact6, num6 * 18 );
dat_file = tr_buildPath( ss->configDir, "dht.dat", NULL );
tr_bencToFile( &benc, TR_FMT_BENC, dat_file );
tr_bencFree( &benc );
tr_free( dat_file );
}
dht_uninit( 1 );
tr_netCloseSocket( dht_socket );
dht_socket = -1;
if(dht6_socket > 0) {
tr_netCloseSocket( dht6_socket );
dht6_socket = -1;
}
tr_ndbg("DHT", "Done uninitializing DHT");
session = NULL;
}
int
main(int argc, char **argv)
{
int i, rc, fd;
int s = -1, s6 = -1, port;
int have_id = 0;
unsigned char myid[20];
time_t tosleep = 0;
char *id_file = "dht-example.id";
int opt;
int quiet = 0, ipv4 = 1, ipv6 = 1;
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
memset(&sin6, 0, sizeof(sin6));
sin6.sin6_family = AF_INET6;
while(1) {
opt = getopt(argc, argv, "q46b:i:");
if(opt < 0)
break;
switch(opt) {
case 'q': quiet = 1; break;
case '4': ipv6 = 0; break;
case '6': ipv4 = 0; break;
case 'b': {
char buf[16];
int rc;
rc = inet_pton(AF_INET, optarg, buf);
if(rc == 1) {
memcpy(&sin.sin_addr, buf, 4);
break;
}
rc = inet_pton(AF_INET6, optarg, buf);
if(rc == 1) {
memcpy(&sin6.sin6_addr, buf, 16);
break;
}
goto usage;
}
break;
case 'i':
id_file = optarg;
break;
default:
goto usage;
}
}
/* Ids need to be distributed evenly, so you cannot just use your
bittorrent id. Either generate it randomly, or take the SHA-1 of
something. */
fd = open(id_file, O_RDONLY);
if(fd >= 0) {
rc = read(fd, myid, 20);
if(rc == 20)
have_id = 1;
close(fd);
}
fd = open("/dev/urandom", O_RDONLY);
if(fd < 0) {
perror("open(random)");
exit(1);
}
if(!have_id) {
int ofd;
rc = read(fd, myid, 20);
if(rc < 0) {
perror("read(random)");
exit(1);
}
have_id = 1;
close(fd);
ofd = open(id_file, O_WRONLY | O_CREAT | O_TRUNC, 0666);
if(ofd >= 0) {
rc = write(ofd, myid, 20);
if(rc < 20)
unlink(id_file);
close(ofd);
}
}
{
unsigned seed;
read(fd, &seed, sizeof(seed));
srandom(seed);
}
close(fd);
if(argc < 2)
goto usage;
i = optind;
if(argc < i + 1)
goto usage;
port = atoi(argv[i++]);
if(port <= 0 || port >= 0x10000)
goto usage;
while(i < argc) {
struct addrinfo hints, *info, *infop;
memset(&hints, 0, sizeof(hints));
hints.ai_socktype = SOCK_DGRAM;
if(!ipv6)
hints.ai_family = AF_INET;
else if(!ipv4)
hints.ai_family = AF_INET6;
else
hints.ai_family = 0;
rc = getaddrinfo(argv[i], argv[i + 1], &hints, &info);
if(rc != 0) {
fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rc));
exit(1);
}
i++;
if(i >= argc)
goto usage;
infop = info;
while(infop) {
memcpy(&bootstrap_nodes[num_bootstrap_nodes],
infop->ai_addr, infop->ai_addrlen);
infop = infop->ai_next;
num_bootstrap_nodes++;
}
freeaddrinfo(info);
i++;
}
/* If you set dht_debug to a stream, every action taken by the DHT will
be logged. */
if(!quiet)
dht_debug = stdout;
/* We need an IPv4 and an IPv6 socket, bound to a stable port. Rumour
has it that uTorrent works better when it is the same as your
Bittorrent port. */
if(ipv4) {
s = socket(PF_INET, SOCK_DGRAM, 0);
if(s < 0) {
perror("socket(IPv4)");
}
}
if(ipv6) {
s6 = socket(PF_INET6, SOCK_DGRAM, 0);
if(s6 < 0) {
perror("socket(IPv6)");
}
}
if(s < 0 && s6 < 0) {
fprintf(stderr, "Eek!");
exit(1);
}
if(s >= 0) {
sin.sin_port = htons(port);
rc = bind(s, (struct sockaddr*)&sin, sizeof(sin));
if(rc < 0) {
perror("bind(IPv4)");
exit(1);
}
}
if(s6 >= 0) {
int rc;
int val = 1;
rc = setsockopt(s6, IPPROTO_IPV6, IPV6_V6ONLY,
(char *)&val, sizeof(val));
if(rc < 0) {
perror("setsockopt(IPV6_V6ONLY)");
exit(1);
}
/* BEP-32 mandates that we should bind this socket to one of our
global IPv6 addresses. In this simple example, this only
happens if the user used the -b flag. */
sin6.sin6_port = htons(port);
rc = bind(s6, (struct sockaddr*)&sin6, sizeof(sin6));
if(rc < 0) {
perror("bind(IPv6)");
exit(1);
}
}
/* Init the dht. This sets the socket into non-blocking mode. */
rc = dht_init(s, s6, myid, (unsigned char*)"JC\0\0");
if(rc < 0) {
perror("dht_init");
exit(1);
}
init_signals();
/* For bootstrapping, we need an initial list of nodes. This could be
hard-wired, but can also be obtained from the nodes key of a torrent
file, or from the PORT bittorrent message.
Dht_ping_node is the brutal way of bootstrapping -- it actually
sends a message to the peer. If you're going to bootstrap from
a massive number of nodes (for example because you're restoring from
a dump) and you already know their ids, it's better to use
dht_insert_node. If the ids are incorrect, the DHT will recover. */
for(i = 0; i < num_bootstrap_nodes; i++) {
dht_ping_node((struct sockaddr*)&bootstrap_nodes[i],
sizeof(bootstrap_nodes[i]));
usleep(random() % 100000);
}
while(1) {
struct timeval tv;
fd_set readfds;
tv.tv_sec = tosleep;
tv.tv_usec = random() % 1000000;
FD_ZERO(&readfds);
if(s >= 0)
FD_SET(s, &readfds);
if(s6 >= 0)
FD_SET(s6, &readfds);
rc = select(s > s6 ? s + 1 : s6 + 1, &readfds, NULL, NULL, &tv);
if(rc < 0) {
if(errno != EINTR) {
perror("select");
sleep(1);
}
}
if(exiting)
break;
rc = dht_periodic(rc > 0, &tosleep, callback, NULL);
if(rc < 0) {
if(errno == EINTR) {
continue;
} else {
perror("dht_periodic");
if(rc == EINVAL || rc == EFAULT)
abort();
tosleep = 1;
}
}
/* This is how you trigger a search for a torrent hash. If port
(the second argument) is non-zero, it also performs an announce.
Since peers expire announced data after 30 minutes, it's a good
idea to reannounce every 28 minutes or so. */
if(searching) {
if(s >= 0)
dht_search(hash, 0, AF_INET, callback, NULL);
if(s6 >= 0)
dht_search(hash, 0, AF_INET6, callback, NULL);
searching = 0;
}
/* For debugging, or idle curiosity. */
if(dumping) {
dht_dump_tables(stdout);
dumping = 0;
}
}
{
struct sockaddr_in sin[500];
struct sockaddr_in6 sin6[500];
int num = 500, num6 = 500;
int i;
i = dht_get_nodes(sin, &num, sin6, &num6);
printf("Found %d (%d + %d) good nodes.\n", i, num, num6);
}
dht_uninit(1);
return 0;
usage:
printf("Usage: dht-example [-q] [-4] [-6] [-i filename] [-b address]...\n"
" port [address port]...\n");
exit(1);
}
