c-libp2p/routing/kademlia.c

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/* 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 <libp2p/crypto/sha256.h>
#include <dht.h>
#define MAX_BOOTSTRAP_NODES 20
static struct sockaddr_storage bootstrap_nodes[MAX_BOOTSTRAP_NODES];
static int num_bootstrap_nodes = 0;
/* 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,
const unsigned char *info_hash,
const void *data, size_t data_len)
{
switch (event) {
case DHT_EVENT_VALUES:
case DHT_EVENT_VALUES6:
printf("Received %d values.\n", (int)(data_len / 6));
break;
case DHT_EVENT_SEARCH_DONE:
case DHT_EVENT_SEARCH_DONE6:
printf("Search done.\n");
break;
default:
break;
}
}
/* Functions called by the DHT. */
int dht_blacklisted (const struct sockaddr *sa, int salen)
{
return 0;
}
/* We need to provide a reasonably strong cryptographic hashing function.
libp2p_crypto_hashing_sha256 */
void dht_hash (void *hash_return, int hash_size,
const void *v1, int len1,
const void *v2, int len2,
const void *v3, int len3)
{
int len = len1 + len2 + len3;
char *in, out[32];
if (!hash_return || hash_size==0 || len==0) {
return; // invalid param.
}
in = malloc (len);
if (in) {
memcpy(in, v1, len1);
memcpy(in+len1, v2, len2);
memcpy(in+len1+len2, v3, len3);
if ( libp2p_crypto_hashing_sha256 (in, len, out) ) {
if (hash_size > sizeof(out)) {
memset ((char*)hash_return + sizeof(out), 0, hash_size - sizeof(out));
hash_size = sizeof(out);
}
memcpy(hash_return, out, hash_size);
}
free (in);
}
}
int dht_random_bytes (void *buf, size_t size)
{
int fd, rc, save;
size_t len = 0;
fd = open("/dev/urandom", O_RDONLY);
if (fd < 0) {
return fd;
}
while (len < size) {
rc = read (fd, buf + len, size - len);
if (rc < 0) {
if (errno == EINTR || errno == EAGAIN) {
continue; // not fatal, try again.
}
if (errno == EWOULDBLOCK && len > 0) {
rc = len;
}
break; // fail.
}
len += rc;
}
if (len > 0 && rc >= 0) {
rc = len;
}
save = errno;
close(fd);
errno = save;
return rc;
}