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/* This software was written by Dirk Engling <erdgeist@erdgeist.org>
It is considered beerware. Prost. Skol. Cheers or whatever.
$id$ */
/* System */
#include <pthread.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <unistd.h>
/* Libowfat */
#include "byte.h"
#include "ip6.h"
#include "ndelay.h"
#include "socket.h"
/* Opentracker */
#include "ot_accesslist.h"
#include "ot_livesync.h"
#include "ot_mutex.h"
#include "ot_stats.h"
#include "trackerlogic.h"
#ifdef WANT_SYNC_LIVE
char groupip_1[4] = {224, 0, 23, 5};
#define LIVESYNC_INCOMING_BUFFSIZE (256 * 256)
#define LIVESYNC_OUTGOING_BUFFSIZE_PEERS 1480
#define LIVESYNC_OUTGOING_WATERMARK_PEERS (sizeof(ot_peer) + sizeof(ot_hash))
#define LIVESYNC_MAXDELAY 15 /* seconds */
enum { OT_SYNC_PEER4, OT_SYNC_PEER6 };
/* Forward declaration */
static void *livesync_worker(void *args);
/* For outgoing packets */
static int64 g_socket_in = -1;
/* For incoming packets */
static int64 g_socket_out = -1;
static pthread_mutex_t g_outbuf_mutex = PTHREAD_MUTEX_INITIALIZER;
typedef struct {
uint8_t data[LIVESYNC_OUTGOING_BUFFSIZE_PEERS];
size_t fill;
ot_time next_packet_time;
} sync_buffer;
static sync_buffer g_v6_buf;
static sync_buffer g_v4_buf;
static pthread_t thread_id;
void livesync_init() {
if (g_socket_in == -1)
exerr("No socket address for live sync specified.");
/* Prepare outgoing peers buffer */
memcpy(g_v6_buf.data, &g_tracker_id, sizeof(g_tracker_id));
memcpy(g_v4_buf.data, &g_tracker_id, sizeof(g_tracker_id));
uint32_pack_big((char *)g_v6_buf.data + sizeof(g_tracker_id), OT_SYNC_PEER6);
uint32_pack_big((char *)g_v4_buf.data + sizeof(g_tracker_id), OT_SYNC_PEER4);
g_v6_buf.fill = sizeof(g_tracker_id) + sizeof(uint32_t);
g_v4_buf.fill = sizeof(g_tracker_id) + sizeof(uint32_t);
g_v6_buf.next_packet_time = g_now_seconds + LIVESYNC_MAXDELAY;
g_v4_buf.next_packet_time = g_now_seconds + LIVESYNC_MAXDELAY;
pthread_create(&thread_id, NULL, livesync_worker, NULL);
}
void livesync_deinit() {
if (g_socket_in != -1)
close(g_socket_in);
if (g_socket_out != -1)
close(g_socket_out);
pthread_cancel(thread_id);
}
void livesync_bind_mcast(ot_ip6 ip, uint16_t port) {
char tmpip[4] = {0, 0, 0, 0};
char *v4ip;
if (!ip6_isv4mapped(ip))
exerr("v6 mcast support not yet available.");
v4ip = ip + 12;
if (g_socket_in != -1)
exerr("Error: Livesync listen ip specified twice.");
if ((g_socket_in = socket_udp4()) < 0)
exerr("Error: Cant create live sync incoming socket.");
ndelay_off(g_socket_in);
if (socket_bind4_reuse(g_socket_in, tmpip, port) == -1)
exerr("Error: Cant bind live sync incoming socket.");
if (socket_mcjoin4(g_socket_in, groupip_1, v4ip))
exerr("Error: Cant make live sync incoming socket join mcast group.");
if ((g_socket_out = socket_udp4()) < 0)
exerr("Error: Cant create live sync outgoing socket.");
if (socket_bind4_reuse(g_socket_out, v4ip, port) == -1)
exerr("Error: Cant bind live sync outgoing socket.");
socket_mcttl4(g_socket_out, 1);
socket_mcloop4(g_socket_out, 0);
}
/* Caller MUST hold g_outbuf_mutex. Returns with g_outbuf_mutex unlocked */
static void livesync_issue_peersync(sync_buffer *buf) {
char mycopy[LIVESYNC_OUTGOING_BUFFSIZE_PEERS];
size_t fill = buf->fill;
memcpy(mycopy, buf->data, fill);
buf->fill = sizeof(g_tracker_id) + sizeof(uint32_t);
buf->next_packet_time = g_now_seconds + LIVESYNC_MAXDELAY;
/* From now this thread has a local copy of the buffer and
has modified the protected element */
pthread_mutex_unlock(&g_outbuf_mutex);
socket_send4(g_socket_out, mycopy, fill, groupip_1, LIVESYNC_PORT);
}
static void livesync_handle_peersync(struct ot_workstruct *ws, size_t peer_size) {
size_t off = sizeof(g_tracker_id) + sizeof(uint32_t);
/* Now basic sanity checks have been done on the live sync packet
We might add more testing and logging. */
while ((ssize_t)(off + sizeof(ot_hash) + peer_size) <= ws->request_size) {
memcpy(&ws->peer, ws->request + off + sizeof(ot_hash), peer_size);
ws->hash = (ot_hash *)(ws->request + off);
if (!g_opentracker_running)
return;
if (OT_PEERFLAG(ws->peer) & PEER_FLAG_STOPPED)
remove_peer_from_torrent(FLAG_MCA, ws);
else
add_peer_to_torrent_and_return_peers(FLAG_MCA, ws, /* amount = */ 0);
off += sizeof(ot_hash) + peer_size;
}
stats_issue_event(EVENT_SYNC, 0, (ws->request_size - sizeof(g_tracker_id) - sizeof(uint32_t)) / ((ssize_t)sizeof(ot_hash) + peer_size));
}
/* Tickle the live sync module from time to time, so no events get
stuck when there's not enough traffic to fill udp packets fast
enough */
void livesync_ticker() {
/* livesync_issue_peersync sets g_next_packet_time */
pthread_mutex_lock(&g_outbuf_mutex);
if (g_now_seconds > g_v6_buf.next_packet_time && g_v6_buf.fill > sizeof(g_tracker_id) + sizeof(uint32_t))
livesync_issue_peersync(&g_v6_buf);
else
pthread_mutex_unlock(&g_outbuf_mutex);
pthread_mutex_lock(&g_outbuf_mutex);
if (g_now_seconds > g_v4_buf.next_packet_time && g_v4_buf.fill > sizeof(g_tracker_id) + sizeof(uint32_t))
livesync_issue_peersync(&g_v4_buf);
else
pthread_mutex_unlock(&g_outbuf_mutex);
}
/* Inform live sync about whats going on. */
void livesync_tell(struct ot_workstruct *ws) {
size_t peer_size; /* initialized in next line */
ot_peer *peer_src = peer_from_peer6(&ws->peer, &peer_size);
sync_buffer *dest_buf = peer_size == OT_PEER_SIZE6 ? &g_v6_buf : &g_v4_buf;
pthread_mutex_lock(&g_outbuf_mutex);
memcpy(dest_buf->data + dest_buf->fill, ws->hash, sizeof(ot_hash));
dest_buf->fill += sizeof(ot_hash);
memcpy(dest_buf->data + dest_buf->fill, peer_src, peer_size);
dest_buf->fill += peer_size;
if (dest_buf->fill >= LIVESYNC_OUTGOING_BUFFSIZE_PEERS - LIVESYNC_OUTGOING_WATERMARK_PEERS)
livesync_issue_peersync(dest_buf);
else
pthread_mutex_unlock(&g_outbuf_mutex);
}
static void *livesync_worker(void *args) {
struct ot_workstruct ws;
ot_ip6 in_ip;
uint16_t in_port;
(void)args;
/* Initialize our "thread local storage" */
ws.inbuf = ws.request = malloc(LIVESYNC_INCOMING_BUFFSIZE);
ws.outbuf = ws.reply = 0;
memcpy(in_ip, V4mappedprefix, sizeof(V4mappedprefix));
while (1) {
ws.request_size = socket_recv4(g_socket_in, (char *)ws.inbuf, LIVESYNC_INCOMING_BUFFSIZE, 12 + (char *)in_ip, &in_port);
/* Expect at least tracker id and packet type */
if (ws.request_size <= (ssize_t)(sizeof(g_tracker_id) + sizeof(uint32_t)))
continue;
if (!accesslist_is_blessed(in_ip, OT_PERMISSION_MAY_LIVESYNC))
continue;
if (!memcmp(ws.inbuf, &g_tracker_id, sizeof(g_tracker_id))) {
/* TODO: log packet coming from ourselves */
continue;
}
switch (uint32_read_big(sizeof(g_tracker_id) + (char *)ws.inbuf)) {
case OT_SYNC_PEER6:
livesync_handle_peersync(&ws, OT_PEER_SIZE6);
break;
case OT_SYNC_PEER4:
livesync_handle_peersync(&ws, OT_PEER_SIZE4);
break;
default:
break;
}
}
/* Never returns. */
return NULL;
}
#endif
const char *g_version_livesync_c = "$Source$: $Revision$\n";
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