7 files changed, 55 insertions, 16 deletions

diff --git a/src/opentracker.c b/src/opentracker.c
index 14b817e..60a6d8c 100644
--- a/src/opentracker.c
+++ b/src/opentracker.c
@@ -109,7 +109,7 @@ static void *server_mainloop(void *args) {
 
   (void)args;
 
-  if (workstruct_init(&ws) == -1)
+  if (workstruct_init(&ws, G_INBUF_SIZE) == -1)
     panic("Initializing worker failed");
 
   while (g_opentracker_running) {
diff --git a/src/ot_config.c b/src/ot_config.c
index 95136b5..4064d1b 100644
--- a/src/ot_config.c
+++ b/src/ot_config.c
@@ -208,6 +208,7 @@ typedef enum {
     CONFIG_TRACKER_REDIRECT_URL,
     CONFIG_LIVESYNC_CLUSTER_NODE_IP,
     CONFIG_LIVESYNC_CLUSTER_LISTEN,
+    CONFIG_LIVESYNC_CLUSTER_GROUP,
 } config_kind;
 
 typedef struct {
@@ -247,6 +248,7 @@ static const config_key config_keys[] = {
 #ifdef WANT_SYNC_LIVE
     CONFIG_KEY("livesync.cluster.node_ip", CONFIG_LIVESYNC_CLUSTER_NODE_IP),
     CONFIG_KEY("livesync.cluster.listen",  CONFIG_LIVESYNC_CLUSTER_LISTEN),
+    CONFIG_KEY("livesync.cluster.group",   CONFIG_LIVESYNC_CLUSTER_GROUP),
 #endif
 };
 static const size_t config_entry_count = sizeof(config_keys) / sizeof(config_keys[0]);
@@ -378,6 +380,10 @@ static int parse_configfile(char *config_filename) {
         set_config_option(&g_redirecturl, p);
         break;
 #ifdef WANT_SYNC_LIVE
+      case CONFIG_LIVESYNC_CLUSTER_GROUP:
+        if (!ip_parse(p, tmpip) || livesync_set_group(tmpip) == -1)
+          goto parse_error;
+        break;
       case CONFIG_LIVESYNC_CLUSTER_NODE_IP:
         if (!scan_ip6_net(p, &tmpnet))
           goto parse_error;
diff --git a/src/ot_livesync.c b/src/ot_livesync.c
index 083fe1a..85577f7 100644
--- a/src/ot_livesync.c
+++ b/src/ot_livesync.c
@@ -4,6 +4,7 @@
 /* System */
 #include <arpa/inet.h>
 #include <pthread.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/socket.h>
@@ -21,7 +22,10 @@
 
 #ifdef WANT_SYNC_LIVE
 
-ot_ip6 groupip_1 = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff, 224, 0, 23, 5};
+/* The multicast group, legacy opentrackers joined by default 224.0.23.5, so it
+   stays the default */
+static ot_ip6   g_group = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff, 224, 0, 23, 5};
+static uint16_t g_port  = LIVESYNC_PORT;
 
 #define LIVESYNC_INCOMING_BUFFSIZE        (256 * 256)
 
@@ -59,7 +63,7 @@ void livesync_init(void) {
   uint32_t packet_type4 = htonl(OT_SYNC_PEER4);
 
   if (g_socket_in == -1)
-    exerr("No socket address for live sync specified.");
+    return;
 
   /* Prepare outgoing peers buffer */
   memcpy(g_v6_buf.data, &g_tracker_id, sizeof(g_tracker_id));
@@ -94,6 +98,14 @@ void livesync_deinit(void) {
     close(g_socket_out);
 }
 
+int livesync_set_group(const ot_ip6 group) {
+  /* v4 multicast is 224.0.0.0/4, and the socket layer has nothing else */
+  if (!ip_is_v4mapped(group) || (group[12] & 0xf0) != 0xe0)
+    return -1;
+  memcpy(g_group, group, sizeof(ot_ip6));
+  return 0;
+}
+
 void livesync_bind_mcast(ot_ip6 ip, uint16_t port) {
   if (!ip_is_v4mapped(ip))
     exerr("v6 mcast support not yet available.");
@@ -101,7 +113,9 @@ void livesync_bind_mcast(ot_ip6 ip, uint16_t port) {
   if (g_socket_in != -1)
     exerr("Error: Livesync listen ip specified twice.");
 
-  if ((g_socket_in = socket_mcast_join(groupip_1, ip, port)) == -1)
+  g_port = port;
+
+  if ((g_socket_in = socket_mcast_join(g_group, ip, port)) == -1)
     exerr("Error: Cant bind live sync incoming socket.");
 
   if ((g_socket_out = socket_mcast_bind(ip, port, 0)) == -1)
@@ -121,7 +135,7 @@ static void livesync_issue_peersync(sync_buffer *buf) {
      has modified the protected element */
   pthread_mutex_unlock(&g_outbuf_mutex);
 
-  socket_mcast_send(g_socket_out, mycopy, fill, groupip_1, LIVESYNC_PORT);
+  socket_mcast_send(g_socket_out, mycopy, fill, g_group, g_port);
 }
 
 static void livesync_handle_peersync(struct ot_workstruct *ws, size_t peer_size) {
@@ -159,6 +173,9 @@ static void livesync_handle_peersync(struct ot_workstruct *ws, size_t peer_size)
    stuck when there's not enough traffic to fill udp packets fast
    enough */
 void livesync_ticker(void) {
+  if (g_socket_out == -1)
+    return;
+
   /* livesync_issue_peersync sets g_next_packet_time */
   pthread_mutex_lock(&g_outbuf_mutex);
   if (time_now_seconds() > g_v6_buf.next_packet_time && g_v6_buf.fill > sizeof(g_tracker_id) + sizeof(uint32_t))
@@ -176,8 +193,14 @@ void livesync_ticker(void) {
 /* 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;
+  ot_peer     *peer_src;
+  sync_buffer *dest_buf;
+
+  if (g_socket_out == -1)
+    return;
+
+  peer_src = peer_from_peer6(&ws->peer, &peer_size);
+  dest_buf = peer_size == OT_PEER_SIZE6 ? &g_v6_buf : &g_v4_buf;
 
   pthread_mutex_lock(&g_outbuf_mutex);
 
@@ -200,9 +223,12 @@ static void *livesync_worker(void *args) {
 
   (void)args;
 
-  /* Initialize our "thread local storage" */
-  ws.inbuf = ws.request = malloc(LIVESYNC_INCOMING_BUFFSIZE);
-  ws.outbuf = ws.reply = 0;
+  if (workstruct_init(&ws, LIVESYNC_INCOMING_BUFFSIZE) == -1) {
+    fprintf(stderr, "Warning: live sync could not get its buffers and will not run.\n");
+    atomic_store(&thread_left, 1);
+    return NULL;
+  }
+  ws.request = ws.inbuf;
 
   while (g_opentracker_running) {
     uint32_t packet_type;
@@ -233,7 +259,7 @@ static void *livesync_worker(void *args) {
     }
   }
 
-  free(ws.inbuf);
+  workstruct_deinit(&ws);
   atomic_store(&thread_left, 1);
   return NULL;
 }
diff --git a/src/ot_livesync.h b/src/ot_livesync.h
index 4bd3af0..cf3c64c 100644
--- a/src/ot_livesync.h
+++ b/src/ot_livesync.h
@@ -7,7 +7,8 @@
 #include "trackerlogic.h"
 
 /*
-  Syncing is done as udp packets in the multicast domain 224.0.42.5 port 9696
+  Syncing is done as udp packets in the multicast group 224.0.23.5, on the
+  port livesync.cluster.listen names, 9696 by default
 
   Each tracker should join the multicast group and send its live sync packets
   to that group, using a ttl of 1
@@ -47,6 +48,10 @@
 void livesync_init(void);
 void livesync_deinit(void);
 
+/* The group to join and to send to, (defaults to 224.0.23.5).
+   Returns -1 if group is not a v4 multicast address. */
+int  livesync_set_group(const ot_ip6 group);
+
 /* Join multicast group for listening and create sending socket */
 void livesync_bind_mcast(ot_ip6 ip, uint16_t port);
 
diff --git a/src/ot_worker.c b/src/ot_worker.c
index 432d272..ef50945 100644
--- a/src/ot_worker.c
+++ b/src/ot_worker.c
@@ -20,7 +20,7 @@ static size_t             g_worker_count;
 static void *worker_trampoline(void *args) {
   struct ot_worker *me = args;
 
-  if (workstruct_init(&me->ws) == -1)
+  if (workstruct_init(&me->ws, G_INBUF_SIZE) == -1)
     fprintf(stderr, "Warning: a worker could not get its buffers and will not run.\n");
   else {
     me->run(me);
diff --git a/src/trackerlogic.c b/src/trackerlogic.c
index 9565090..8e30a48 100644
--- a/src/trackerlogic.c
+++ b/src/trackerlogic.c
@@ -567,9 +567,11 @@ void trackerlogic_init(void) {
   stats_init();
 }
 
-int workstruct_init(struct ot_workstruct *ws) {
+/* Live sync reads whole packets rather than requests and wants a larger
+   inbuf than the request path does, hence the size. */
+int workstruct_init(struct ot_workstruct *ws, size_t inbuf_size) {
   memset(ws, 0, sizeof(*ws));
-  ws->inbuf  = malloc(G_INBUF_SIZE);
+  ws->inbuf  = malloc(inbuf_size);
   ws->outbuf = malloc(G_OUTBUF_SIZE);
 #ifdef _DEBUG_HTTPERROR
   ws->debugbuf = malloc(G_DEBUGBUF_SIZE);
diff --git a/src/trackerlogic.h b/src/trackerlogic.h
index 7292d36..692b6af 100644
--- a/src/trackerlogic.h
+++ b/src/trackerlogic.h
@@ -242,7 +242,7 @@ struct ot_workstruct {
 /* Everything a thread that serves requests needs for itself. Set up and torn
    down in one place so that a new kind of worker cannot miss a piece.
    Returns -1 if the buffers could not be had. */
-int  workstruct_init(struct ot_workstruct *ws);
+int  workstruct_init(struct ot_workstruct *ws, size_t inbuf_size);
 void workstruct_deinit(struct ot_workstruct *ws);
 
 /*