mirror of
https://github.com/transmission/transmission
synced 2024-12-28 10:38:45 +00:00
346 lines
8.5 KiB
C
346 lines
8.5 KiB
C
/* This example code was written by Juliusz Chroboczek.
|
|
You are free to cut'n'paste from it to your heart's content. */
|
|
|
|
/* For crypt */
|
|
#define _GNU_SOURCE
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <errno.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
#include <fcntl.h>
|
|
#include <sys/time.h>
|
|
#include <arpa/inet.h>
|
|
#include <sys/types.h>
|
|
#include <sys/socket.h>
|
|
#include <netdb.h>
|
|
#include <sys/signal.h>
|
|
|
|
#include "dht.h"
|
|
|
|
#define MAX_BOOTSTRAP_NODES 20
|
|
static struct sockaddr_in bootstrap_nodes[MAX_BOOTSTRAP_NODES];
|
|
static int num_bootstrap_nodes = 0;
|
|
|
|
static volatile sig_atomic_t dumping = 0, searching = 0, exiting = 0;
|
|
|
|
static void
|
|
sigdump(int signo)
|
|
{
|
|
dumping = 1;
|
|
}
|
|
|
|
static void
|
|
sigtest(int signo)
|
|
{
|
|
searching = 1;
|
|
}
|
|
|
|
static void
|
|
sigexit(int signo)
|
|
{
|
|
exiting = 1;
|
|
}
|
|
|
|
static void
|
|
init_signals(void)
|
|
{
|
|
struct sigaction sa;
|
|
sigset_t ss;
|
|
|
|
sigemptyset(&ss);
|
|
sa.sa_handler = sigdump;
|
|
sa.sa_mask = ss;
|
|
sa.sa_flags = 0;
|
|
sigaction(SIGUSR1, &sa, NULL);
|
|
|
|
sigemptyset(&ss);
|
|
sa.sa_handler = sigtest;
|
|
sa.sa_mask = ss;
|
|
sa.sa_flags = 0;
|
|
sigaction(SIGUSR2, &sa, NULL);
|
|
|
|
sigemptyset(&ss);
|
|
sa.sa_handler = sigexit;
|
|
sa.sa_mask = ss;
|
|
sa.sa_flags = 0;
|
|
sigaction(SIGINT, &sa, NULL);
|
|
}
|
|
|
|
const unsigned char hash[20] = {
|
|
0x54, 0x57, 0x87, 0x89, 0xdf, 0xc4, 0x23, 0xee, 0xf6, 0x03,
|
|
0x1f, 0x81, 0x94, 0xa9, 0x3a, 0x16, 0x98, 0x8b, 0x72, 0x7b
|
|
};
|
|
|
|
/* The call-back function is called by the DHT whenever something
|
|
interesting happens. Right now, it only happens when we get a new value or
|
|
when a search completes, but this may be extended in future versions. */
|
|
static void
|
|
callback(void *closure,
|
|
int event,
|
|
unsigned char *info_hash,
|
|
void *data, size_t data_len)
|
|
{
|
|
if(event == DHT_EVENT_SEARCH_DONE)
|
|
printf("Search done.\n");
|
|
else if(event == DHT_EVENT_VALUES)
|
|
printf("Received %d values.\n", (int)(data_len / 6));
|
|
}
|
|
|
|
int
|
|
main(int argc, char **argv)
|
|
{
|
|
int i, rc, fd;
|
|
int s, port;
|
|
int have_id = 0;
|
|
unsigned char myid[20];
|
|
time_t tosleep = 0;
|
|
|
|
/* 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("dht-example.id", O_RDONLY);
|
|
if(fd >= 0) {
|
|
rc = read(fd, myid, 20);
|
|
if(rc == 20)
|
|
have_id = 1;
|
|
close(fd);
|
|
}
|
|
|
|
if(!have_id) {
|
|
fd = open("/dev/urandom", O_RDONLY);
|
|
if(fd < 0) {
|
|
perror("open(random)");
|
|
exit(1);
|
|
}
|
|
rc = read(fd, myid, 20);
|
|
if(rc < 0) {
|
|
perror("read(random)");
|
|
exit(1);
|
|
}
|
|
have_id = 1;
|
|
close(fd);
|
|
|
|
fd = open("dht-example.id", O_WRONLY | O_CREAT | O_TRUNC, 0666);
|
|
if(fd >= 0) {
|
|
rc = write(fd, myid, 20);
|
|
if(rc < 20)
|
|
unlink("dht-example.id");
|
|
close(fd);
|
|
}
|
|
}
|
|
|
|
if(argc < 2)
|
|
goto usage;
|
|
|
|
i = 1;
|
|
|
|
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_family = AF_INET;
|
|
hints.ai_socktype = SOCK_DGRAM;
|
|
rc = getaddrinfo(argv[i], NULL, &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) {
|
|
if(infop->ai_addr->sa_family == AF_INET) {
|
|
struct sockaddr_in sin;
|
|
memcpy(&sin, infop->ai_addr, infop->ai_addrlen);
|
|
sin.sin_port = htons(atoi(argv[i]));
|
|
bootstrap_nodes[num_bootstrap_nodes] = sin;
|
|
num_bootstrap_nodes++;
|
|
}
|
|
infop = infop->ai_next;
|
|
}
|
|
freeaddrinfo(info);
|
|
|
|
i++;
|
|
}
|
|
|
|
/* If you set dht_debug to a stream, every action taken by the DHT will
|
|
be logged. */
|
|
dht_debug = stdout;
|
|
|
|
/* We need an IPv4 socket, bound to a stable port. Rumour has it that
|
|
uTorrent works better when it is the same as your Bittorrent port. */
|
|
s = socket(PF_INET, SOCK_DGRAM, 0);
|
|
if(s < 0) {
|
|
perror("socket");
|
|
exit(1);
|
|
}
|
|
|
|
{
|
|
struct sockaddr_in sin;
|
|
memset(&sin, 0, sizeof(sin));
|
|
sin.sin_family = AF_INET;
|
|
sin.sin_port = htons(port);
|
|
rc = bind(s, (struct sockaddr*)&sin, sizeof(sin));
|
|
if(rc < 0) {
|
|
perror("bind");
|
|
exit(1);
|
|
}
|
|
}
|
|
|
|
/* Init the dht. This sets the socket into non-blocking mode. */
|
|
rc = dht_init(s, myid, NULL);
|
|
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(s, &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);
|
|
FD_SET(s, &readfds);
|
|
rc = select(s + 1, &readfds, NULL, NULL, &tv);
|
|
if(rc < 0) {
|
|
if(errno != EINTR) {
|
|
perror("select");
|
|
sleep(1);
|
|
}
|
|
}
|
|
|
|
if(exiting)
|
|
break;
|
|
|
|
rc = dht_periodic(s, 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 third 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) {
|
|
dht_search(s, hash, 0, callback, NULL);
|
|
searching = 0;
|
|
}
|
|
|
|
/* For debugging, or idle curiosity. */
|
|
if(dumping) {
|
|
dht_dump_tables(stdout);
|
|
dumping = 0;
|
|
}
|
|
}
|
|
|
|
{
|
|
struct sockaddr_in sins[500];
|
|
int i;
|
|
i = dht_get_nodes(sins, 500);
|
|
printf("Found %d good nodes.\n", i);
|
|
}
|
|
|
|
dht_uninit(s, 1);
|
|
return 0;
|
|
|
|
usage:
|
|
fprintf(stderr, "Foo!\n");
|
|
exit(1);
|
|
}
|
|
|
|
/* We need to provide a reasonably strong cryptographic hashing function.
|
|
Here's how we'd do it if we had RSA's MD5 code. */
|
|
#if 0
|
|
void
|
|
dht_hash(void *hash_return, int hash_size,
|
|
const void *v1, int len1,
|
|
const void *v2, int len2,
|
|
const void *v3, int len3)
|
|
{
|
|
static MD5_CTX ctx;
|
|
MD5Init(&ctx);
|
|
MD5Update(&ctx, v1, len1);
|
|
MD5Update(&ctx, v2, len2);
|
|
MD5Update(&ctx, v3, len3);
|
|
MD5Final(&ctx);
|
|
if(hash_size > 16)
|
|
memset((char*)hash_return + 16, 0, hash_size - 16);
|
|
memcpy(hash_return, ctx.digest, hash_size > 16 ? 16 : hash_size);
|
|
}
|
|
#else
|
|
/* But for this example, we might as well use something weaker. */
|
|
void
|
|
dht_hash(void *hash_return, int hash_size,
|
|
const void *v1, int len1,
|
|
const void *v2, int len2,
|
|
const void *v3, int len3)
|
|
{
|
|
const char *c1 = v1, *c2 = v2, *c3 = v3;
|
|
char key[9]; /* crypt is limited to 8 characters */
|
|
int i;
|
|
|
|
memset(key, 0, 9);
|
|
#define CRYPT_HAPPY(c) ((c % 0x60) + 0x20)
|
|
|
|
for(i = 0; i < 2 && i < len1; i++)
|
|
key[i] = CRYPT_HAPPY(c1[i]);
|
|
for(i = 0; i < 4 && i < len1; i++)
|
|
key[2 + i] = CRYPT_HAPPY(c2[i]);
|
|
for(i = 0; i < 2 && i < len1; i++)
|
|
key[6 + i] = CRYPT_HAPPY(c3[i]);
|
|
strncpy(hash_return, crypt(key, "jc"), hash_size);
|
|
}
|
|
#endif
|
|
|
|
int
|
|
dht_random_bytes(void *buf, size_t size)
|
|
{
|
|
int fd, rc, save;
|
|
|
|
fd = open("/dev/urandom", O_RDONLY);
|
|
if(fd < 0)
|
|
return -1;
|
|
|
|
rc = read(fd, buf, size);
|
|
|
|
save = errno;
|
|
close(fd);
|
|
errno = save;
|
|
|
|
return rc;
|
|
}
|