path: root/ctdb/server/ctdb_takeover.c

/* 
   ctdb ip takeover code

   Copyright (C) Ronnie Sahlberg  2007
   Copyright (C) Andrew Tridgell  2007
   Copyright (C) Martin Schwenke  2011

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "lib/tdb/include/tdb.h"
#include "lib/util/dlinklist.h"
#include "system/network.h"
#include "system/filesys.h"
#include "system/wait.h"
#include "../include/ctdb_private.h"
#include "../common/rb_tree.h"


#define TAKEOVER_TIMEOUT() timeval_current_ofs(ctdb->tunable.takeover_timeout,0)

#define CTDB_ARP_INTERVAL 1
#define CTDB_ARP_REPEAT   3

struct ctdb_iface {
	struct ctdb_iface *prev, *next;
	const char *name;
	bool link_up;
	uint32_t references;
};

static const char *ctdb_vnn_iface_string(const struct ctdb_vnn *vnn)
{
	if (vnn->iface) {
		return vnn->iface->name;
	}

	return "__none__";
}

static int ctdb_add_local_iface(struct ctdb_context *ctdb, const char *iface)
{
	struct ctdb_iface *i;

	/* Verify that we dont have an entry for this ip yet */
	for (i=ctdb->ifaces;i;i=i->next) {
		if (strcmp(i->name, iface) == 0) {
			return 0;
		}
	}

	/* create a new structure for this interface */
	i = talloc_zero(ctdb, struct ctdb_iface);
	CTDB_NO_MEMORY_FATAL(ctdb, i);
	i->name = talloc_strdup(i, iface);
	CTDB_NO_MEMORY(ctdb, i->name);
	i->link_up = false;

	DLIST_ADD(ctdb->ifaces, i);

	return 0;
}

static struct ctdb_iface *ctdb_find_iface(struct ctdb_context *ctdb,
					  const char *iface)
{
	struct ctdb_iface *i;

	/* Verify that we dont have an entry for this ip yet */
	for (i=ctdb->ifaces;i;i=i->next) {
		if (strcmp(i->name, iface) == 0) {
			return i;
		}
	}

	return NULL;
}

static struct ctdb_iface *ctdb_vnn_best_iface(struct ctdb_context *ctdb,
					      struct ctdb_vnn *vnn)
{
	int i;
	struct ctdb_iface *cur = NULL;
	struct ctdb_iface *best = NULL;

	for (i=0; vnn->ifaces[i]; i++) {

		cur = ctdb_find_iface(ctdb, vnn->ifaces[i]);
		if (cur == NULL) {
			continue;
		}

		if (!cur->link_up) {
			continue;
		}

		if (best == NULL) {
			best = cur;
			continue;
		}

		if (cur->references < best->references) {
			best = cur;
			continue;
		}
	}

	return best;
}

static int32_t ctdb_vnn_assign_iface(struct ctdb_context *ctdb,
				     struct ctdb_vnn *vnn)
{
	struct ctdb_iface *best = NULL;

	if (vnn->iface) {
		DEBUG(DEBUG_INFO, (__location__ " public address '%s' "
				   "still assigned to iface '%s'\n",
				   ctdb_addr_to_str(&vnn->public_address),
				   ctdb_vnn_iface_string(vnn)));
		return 0;
	}

	best = ctdb_vnn_best_iface(ctdb, vnn);
	if (best == NULL) {
		DEBUG(DEBUG_ERR, (__location__ " public address '%s' "
				  "cannot assign to iface any iface\n",
				  ctdb_addr_to_str(&vnn->public_address)));
		return -1;
	}

	vnn->iface = best;
	best->references++;
	vnn->pnn = ctdb->pnn;

	DEBUG(DEBUG_INFO, (__location__ " public address '%s' "
			   "now assigned to iface '%s' refs[%d]\n",
			   ctdb_addr_to_str(&vnn->public_address),
			   ctdb_vnn_iface_string(vnn),
			   best->references));
	return 0;
}

static void ctdb_vnn_unassign_iface(struct ctdb_context *ctdb,
				    struct ctdb_vnn *vnn)
{
	DEBUG(DEBUG_INFO, (__location__ " public address '%s' "
			   "now unassigned (old iface '%s' refs[%d])\n",
			   ctdb_addr_to_str(&vnn->public_address),
			   ctdb_vnn_iface_string(vnn),
			   vnn->iface?vnn->iface->references:0));
	if (vnn->iface) {
		vnn->iface->references--;
	}
	vnn->iface = NULL;
	if (vnn->pnn == ctdb->pnn) {
		vnn->pnn = -1;
	}
}

static bool ctdb_vnn_available(struct ctdb_context *ctdb,
			       struct ctdb_vnn *vnn)
{
	int i;

	if (vnn->iface && vnn->iface->link_up) {
		return true;
	}

	for (i=0; vnn->ifaces[i]; i++) {
		struct ctdb_iface *cur;

		cur = ctdb_find_iface(ctdb, vnn->ifaces[i]);
		if (cur == NULL) {
			continue;
		}

		if (cur->link_up) {
			return true;
		}
	}

	return false;
}

struct ctdb_takeover_arp {
	struct ctdb_context *ctdb;
	uint32_t count;
	ctdb_sock_addr addr;
	struct ctdb_tcp_array *tcparray;
	struct ctdb_vnn *vnn;
};


/*
  lists of tcp endpoints
 */
struct ctdb_tcp_list {
	struct ctdb_tcp_list *prev, *next;
	struct ctdb_tcp_connection connection;
};

/*
  list of clients to kill on IP release
 */
struct ctdb_client_ip {
	struct ctdb_client_ip *prev, *next;
	struct ctdb_context *ctdb;
	ctdb_sock_addr addr;
	uint32_t client_id;
};


/*
  send a gratuitous arp
 */
static void ctdb_control_send_arp(struct event_context *ev, struct timed_event *te, 
				  struct timeval t, void *private_data)
{
	struct ctdb_takeover_arp *arp = talloc_get_type(private_data, 
							struct ctdb_takeover_arp);
	int i, ret;
	struct ctdb_tcp_array *tcparray;
	const char *iface = ctdb_vnn_iface_string(arp->vnn);

	ret = ctdb_sys_send_arp(&arp->addr, iface);
	if (ret != 0) {
		DEBUG(DEBUG_CRIT,(__location__ " sending of arp failed on iface '%s' (%s)\n",
				  iface, strerror(errno)));
	}

	tcparray = arp->tcparray;
	if (tcparray) {
		for (i=0;i<tcparray->num;i++) {
			struct ctdb_tcp_connection *tcon;

			tcon = &tcparray->connections[i];
			DEBUG(DEBUG_INFO,("sending tcp tickle ack for %u->%s:%u\n",
				(unsigned)ntohs(tcon->dst_addr.ip.sin_port), 
				ctdb_addr_to_str(&tcon->src_addr),
				(unsigned)ntohs(tcon->src_addr.ip.sin_port)));
			ret = ctdb_sys_send_tcp(
				&tcon->src_addr, 
				&tcon->dst_addr,
				0, 0, 0);
			if (ret != 0) {
				DEBUG(DEBUG_CRIT,(__location__ " Failed to send tcp tickle ack for %s\n",
					ctdb_addr_to_str(&tcon->src_addr)));
			}
		}
	}

	arp->count++;

	if (arp->count == CTDB_ARP_REPEAT) {
		talloc_free(arp);
		return;
	}

	event_add_timed(arp->ctdb->ev, arp->vnn->takeover_ctx, 
			timeval_current_ofs(CTDB_ARP_INTERVAL, 100000), 
			ctdb_control_send_arp, arp);
}

static int32_t ctdb_announce_vnn_iface(struct ctdb_context *ctdb,
				       struct ctdb_vnn *vnn)
{
	struct ctdb_takeover_arp *arp;
	struct ctdb_tcp_array *tcparray;

	if (!vnn->takeover_ctx) {
		vnn->takeover_ctx = talloc_new(vnn);
		if (!vnn->takeover_ctx) {
			return -1;
		}
	}

	arp = talloc_zero(vnn->takeover_ctx, struct ctdb_takeover_arp);
	if (!arp) {
		return -1;
	}

	arp->ctdb = ctdb;
	arp->addr = vnn->public_address;
	arp->vnn  = vnn;

	tcparray = vnn->tcp_array;
	if (tcparray) {
		/* add all of the known tcp connections for this IP to the
		   list of tcp connections to send tickle acks for */
		arp->tcparray = talloc_steal(arp, tcparray);

		vnn->tcp_array = NULL;
		vnn->tcp_update_needed = true;
	}

	event_add_timed(arp->ctdb->ev, vnn->takeover_ctx,
			timeval_zero(), ctdb_control_send_arp, arp);

	return 0;
}

struct takeover_callback_state {
	struct ctdb_req_control *c;
	ctdb_sock_addr *addr;
	struct ctdb_vnn *vnn;
};

struct ctdb_do_takeip_state {
	struct ctdb_req_control *c;
	struct ctdb_vnn *vnn;
};

/*
  called when takeip event finishes
 */
static void ctdb_do_takeip_callback(struct ctdb_context *ctdb, int status,
				    void *private_data)
{
	struct ctdb_do_takeip_state *state =
		talloc_get_type(private_data, struct ctdb_do_takeip_state);
	int32_t ret;
	TDB_DATA data;

	if (status != 0) {
		struct ctdb_node *node = ctdb->nodes[ctdb->pnn];
	
		if (status == -ETIME) {
			ctdb_ban_self(ctdb);
		}
		DEBUG(DEBUG_ERR,(__location__ " Failed to takeover IP %s on interface %s\n",
				 ctdb_addr_to_str(&state->vnn->public_address),
				 ctdb_vnn_iface_string(state->vnn)));
		ctdb_request_control_reply(ctdb, state->c, NULL, status, NULL);

		node->flags |= NODE_FLAGS_UNHEALTHY;
		talloc_free(state);
		return;
	}

	ret = ctdb_announce_vnn_iface(ctdb, state->vnn);
	if (ret != 0) {
		ctdb_request_control_reply(ctdb, state->c, NULL, -1, NULL);
		talloc_free(state);
		return;
	}

	data.dptr  = (uint8_t *)ctdb_addr_to_str(&state->vnn->public_address);
	data.dsize = strlen((char *)data.dptr) + 1;
	DEBUG(DEBUG_INFO,(__location__ " sending TAKE_IP for '%s'\n", data.dptr));

	ctdb_daemon_send_message(ctdb, ctdb->pnn, CTDB_SRVID_TAKE_IP, data);


	/* the control succeeded */
	ctdb_request_control_reply(ctdb, state->c, NULL, 0, NULL);
	talloc_free(state);
	return;
}

/*
  take over an ip address
 */
static int32_t ctdb_do_takeip(struct ctdb_context *ctdb,
			      struct ctdb_req_control *c,
			      struct ctdb_vnn *vnn)
{
	int ret;
	struct ctdb_do_takeip_state *state;

	ret = ctdb_vnn_assign_iface(ctdb, vnn);
	if (ret != 0) {
		DEBUG(DEBUG_ERR,("Takeover of IP %s/%u failed to "
				 "assin a usable interface\n",
				 ctdb_addr_to_str(&vnn->public_address),
				 vnn->public_netmask_bits));
		return -1;
	}

	state = talloc(vnn, struct ctdb_do_takeip_state);
	CTDB_NO_MEMORY(ctdb, state);

	state->c = talloc_steal(ctdb, c);
	state->vnn   = vnn;

	DEBUG(DEBUG_NOTICE,("Takeover of IP %s/%u on interface %s\n",
			    ctdb_addr_to_str(&vnn->public_address),
			    vnn->public_netmask_bits,
			    ctdb_vnn_iface_string(vnn)));

	ret = ctdb_event_script_callback(ctdb,
					 state,
					 ctdb_do_takeip_callback,
					 state,
					 false,
					 CTDB_EVENT_TAKE_IP,
					 "%s %s %u",
					 ctdb_vnn_iface_string(vnn),
					 ctdb_addr_to_str(&vnn->public_address),
					 vnn->public_netmask_bits);

	if (ret != 0) {
		DEBUG(DEBUG_ERR,(__location__ " Failed to takeover IP %s on interface %s\n",
			ctdb_addr_to_str(&vnn->public_address),
			ctdb_vnn_iface_string(vnn)));
		talloc_free(state);
		return -1;
	}

	return 0;
}

struct ctdb_do_updateip_state {
	struct ctdb_req_control *c;
	struct ctdb_iface *old;
	struct ctdb_vnn *vnn;
};

/*
  called when updateip event finishes
 */
static void ctdb_do_updateip_callback(struct ctdb_context *ctdb, int status,
				      void *private_data)
{
	struct ctdb_do_updateip_state *state =
		talloc_get_type(private_data, struct ctdb_do_updateip_state);
	int32_t ret;

	if (status != 0) {
		if (status == -ETIME) {
			ctdb_ban_self(ctdb);
		}
		DEBUG(DEBUG_ERR,(__location__ " Failed to move IP %s from interface %s to %s\n",
			ctdb_addr_to_str(&state->vnn->public_address),
			state->old->name,
			ctdb_vnn_iface_string(state->vnn)));

		/*
		 * All we can do is reset the old interface
		 * and let the next run fix it
		 */
		ctdb_vnn_unassign_iface(ctdb, state->vnn);
		state->vnn->iface = state->old;
		state->vnn->iface->references++;

		ctdb_request_control_reply(ctdb, state->c, NULL, status, NULL);
		talloc_free(state);
		return;
	}

	ret = ctdb_announce_vnn_iface(ctdb, state->vnn);
	if (ret != 0) {
		ctdb_request_control_reply(ctdb, state->c, NULL, -1, NULL);
		talloc_free(state);
		return;
	}

	/* the control succeeded */
	ctdb_request_control_reply(ctdb, state->c, NULL, 0, NULL);
	talloc_free(state);
	return;
}

/*
  update (move) an ip address
 */
static int32_t ctdb_do_updateip(struct ctdb_context *ctdb,
				struct ctdb_req_control *c,
				struct ctdb_vnn *vnn)
{
	int ret;
	struct ctdb_do_updateip_state *state;
	struct ctdb_iface *old = vnn->iface;
	const char *new_name;

	ctdb_vnn_unassign_iface(ctdb, vnn);
	ret = ctdb_vnn_assign_iface(ctdb, vnn);
	if (ret != 0) {
		DEBUG(DEBUG_ERR,("update of IP %s/%u failed to "
				 "assin a usable interface (old iface '%s')\n",
				 ctdb_addr_to_str(&vnn->public_address),
				 vnn->public_netmask_bits,
				 old->name));
		return -1;
	}

	new_name = ctdb_vnn_iface_string(vnn);
	if (old->name != NULL && new_name != NULL && !strcmp(old->name, new_name)) {
		/* A benign update from one interface onto itself.
		 * no need to run the eventscripts in this case, just return
		 * success.
		 */
		ctdb_request_control_reply(ctdb, c, NULL, 0, NULL);
		return 0;
	}

	state = talloc(vnn, struct ctdb_do_updateip_state);
	CTDB_NO_MEMORY(ctdb, state);

	state->c = talloc_steal(ctdb, c);
	state->old = old;
	state->vnn = vnn;

	DEBUG(DEBUG_NOTICE,("Update of IP %s/%u from "
			    "interface %s to %s\n",
			    ctdb_addr_to_str(&vnn->public_address),
			    vnn->public_netmask_bits,
			    old->name,
			    new_name));

	ret = ctdb_event_script_callback(ctdb,
					 state,
					 ctdb_do_updateip_callback,
					 state,
					 false,
					 CTDB_EVENT_UPDATE_IP,
					 "%s %s %s %u",
					 state->old->name,
					 new_name,
					 ctdb_addr_to_str(&vnn->public_address),
					 vnn->public_netmask_bits);
	if (ret != 0) {
		DEBUG(DEBUG_ERR,(__location__ " Failed update IP %s from interface %s to %s\n",
				 ctdb_addr_to_str(&vnn->public_address),
				 old->name, new_name));
		talloc_free(state);
		return -1;
	}

	return 0;
}

/*
  Find the vnn of the node that has a public ip address
  returns -1 if the address is not known as a public address
 */
static struct ctdb_vnn *find_public_ip_vnn(struct ctdb_context *ctdb, ctdb_sock_addr *addr)
{
	struct ctdb_vnn *vnn;

	for (vnn=ctdb->vnn;vnn;vnn=vnn->next) {
		if (ctdb_same_ip(&vnn->public_address, addr)) {
			return vnn;
		}
	}

	return NULL;
}

/*
  take over an ip address
 */
int32_t ctdb_control_takeover_ip(struct ctdb_context *ctdb,
				 struct ctdb_req_control *c,
				 TDB_DATA indata,
				 bool *async_reply)
{
	int ret;
	struct ctdb_public_ip *pip = (struct ctdb_public_ip *)indata.dptr;
	struct ctdb_vnn *vnn;
	bool have_ip = false;
	bool do_updateip = false;
	bool do_takeip = false;
	struct ctdb_iface *best_iface = NULL;

	if (pip->pnn != ctdb->pnn) {
		DEBUG(DEBUG_ERR,(__location__" takeoverip called for an ip '%s' "
				 "with pnn %d, but we're node %d\n",
				 ctdb_addr_to_str(&pip->addr),
				 pip->pnn, ctdb->pnn));
		return -1;
	}

	/* update out vnn list */
	vnn = find_public_ip_vnn(ctdb, &pip->addr);
	if (vnn == NULL) {
		DEBUG(DEBUG_INFO,("takeoverip called for an ip '%s' that is not a public address\n",
			ctdb_addr_to_str(&pip->addr)));
		return 0;
	}

	have_ip = ctdb_sys_have_ip(&pip->addr);
	best_iface = ctdb_vnn_best_iface(ctdb, vnn);
	if (best_iface == NULL) {
		DEBUG(DEBUG_ERR,("takeoverip of IP %s/%u failed to find"
				 "a usable interface (old %s, have_ip %d)\n",
				 ctdb_addr_to_str(&vnn->public_address),
				 vnn->public_netmask_bits,
				 ctdb_vnn_iface_string(vnn),
				 have_ip));
		return -1;
	}

	if (vnn->iface == NULL && vnn->pnn == -1 && have_ip && best_iface != NULL) {
		DEBUG(DEBUG_ERR,("Taking over newly created ip\n"));
		have_ip = false;
	}

	if (vnn->iface == NULL && have_ip) {
		DEBUG(DEBUG_CRIT,(__location__ " takeoverip of IP %s is known to the kernel, "
				  "but we have no interface assigned, has someone manually configured it? Ignore for now.\n",
				 ctdb_addr_to_str(&vnn->public_address)));
		return 0;
	}

	if (vnn->pnn != ctdb->pnn && have_ip && vnn->pnn != -1) {
		DEBUG(DEBUG_CRIT,(__location__ " takeoverip of IP %s is known to the kernel, "
				  "and we have it on iface[%s], but it was assigned to node %d"
				  "and we are node %d, banning ourself\n",
				 ctdb_addr_to_str(&vnn->public_address),
				 ctdb_vnn_iface_string(vnn), vnn->pnn, ctdb->pnn));
		ctdb_ban_self(ctdb);
		return -1;
	}

	if (vnn->pnn == -1 && have_ip) {
		vnn->pnn = ctdb->pnn;
		DEBUG(DEBUG_CRIT,(__location__ " takeoverip of IP %s is known to the kernel, "
				  "and we already have it on iface[%s], update local daemon\n",
				 ctdb_addr_to_str(&vnn->public_address),
				  ctdb_vnn_iface_string(vnn)));
		return 0;
	}

	if (vnn->iface) {
		if (vnn->iface->link_up) {
			/* only move when the rebalance gains something */
			if (vnn->iface->references > (best_iface->references + 1)) {
				do_updateip = true;
			}
		} else if (vnn->iface != best_iface) {
			do_updateip = true;
		}
	}

	if (!have_ip) {
		if (do_updateip) {
			ctdb_vnn_unassign_iface(ctdb, vnn);
			do_updateip = false;
		}
		do_takeip = true;
	}

	if (do_takeip) {
		ret = ctdb_do_takeip(ctdb, c, vnn);
		if (ret != 0) {
			return -1;
		}
	} else if (do_updateip) {
		ret = ctdb_do_updateip(ctdb, c, vnn);
		if (ret != 0) {
			return -1;
		}
	} else {
		/*
		 * The interface is up and the kernel known the ip
		 * => do nothing
		 */
		DEBUG(DEBUG_INFO,("Redundant takeover of IP %s/%u on interface %s (ip already held)\n",
			ctdb_addr_to_str(&pip->addr),
			vnn->public_netmask_bits,
			ctdb_vnn_iface_string(vnn)));
		return 0;
	}

	/* tell ctdb_control.c that we will be replying asynchronously */
	*async_reply = true;

	return 0;
}

/*
  takeover an ip address old v4 style
 */
int32_t ctdb_control_takeover_ipv4(struct ctdb_context *ctdb, 
				struct ctdb_req_control *c,
				TDB_DATA indata, 
				bool *async_reply)
{
	TDB_DATA data;
	
	data.dsize = sizeof(struct ctdb_public_ip);
	data.dptr  = (uint8_t *)talloc_zero(c, struct ctdb_public_ip);
	CTDB_NO_MEMORY(ctdb, data.dptr);
	
	memcpy(data.dptr, indata.dptr, indata.dsize);
	return ctdb_control_takeover_ip(ctdb, c, data, async_reply);
}

/*
  kill any clients that are registered with a IP that is being released
 */
static void release_kill_clients(struct ctdb_context *ctdb, ctdb_sock_addr *addr)
{
	struct ctdb_client_ip *ip;

	DEBUG(DEBUG_INFO,("release_kill_clients for ip %s\n",
		ctdb_addr_to_str(addr)));

	for (ip=ctdb->client_ip_list; ip; ip=ip->next) {
		ctdb_sock_addr tmp_addr;

		tmp_addr = ip->addr;
		DEBUG(DEBUG_INFO,("checking for client %u with IP %s\n", 
			ip->client_id,
			ctdb_addr_to_str(&ip->addr)));

		if (ctdb_same_ip(&tmp_addr, addr)) {
			struct ctdb_client *client = ctdb_reqid_find(ctdb, 
								     ip->client_id, 
								     struct ctdb_client);
			DEBUG(DEBUG_INFO,("matched client %u with IP %s and pid %u\n", 
				ip->client_id,
				ctdb_addr_to_str(&ip->addr),
				client->pid));

			if (client->pid != 0) {
				DEBUG(DEBUG_INFO,(__location__ " Killing client pid %u for IP %s on client_id %u\n",
					(unsigned)client->pid,
					ctdb_addr_to_str(addr),
					ip->client_id));
				kill(client->pid, SIGKILL);
			}
		}
	}
}

/*
  called when releaseip event finishes
 */
static void release_ip_callback(struct ctdb_context *ctdb, int status, 
				void *private_data)
{
	struct takeover_callback_state *state = 
		talloc_get_type(private_data, struct takeover_callback_state);
	TDB_DATA data;

	if (status == -ETIME) {
		ctdb_ban_self(ctdb);
	}

	/* send a message to all clients of this node telling them
	   that the cluster has been reconfigured and they should
	   release any sockets on this IP */
	data.dptr = (uint8_t *)talloc_strdup(state, ctdb_addr_to_str(state->addr));
	CTDB_NO_MEMORY_VOID(ctdb, data.dptr);
	data.dsize = strlen((char *)data.dptr)+1;

	DEBUG(DEBUG_INFO,(__location__ " sending RELEASE_IP for '%s'\n", data.dptr));

	ctdb_daemon_send_message(ctdb, ctdb->pnn, CTDB_SRVID_RELEASE_IP, data);

	/* kill clients that have registered with this IP */
	release_kill_clients(ctdb, state->addr);

	ctdb_vnn_unassign_iface(ctdb, state->vnn);

	/* the control succeeded */
	ctdb_request_control_reply(ctdb, state->c, NULL, 0, NULL);
	talloc_free(state);
}

/*
  release an ip address
 */
int32_t ctdb_control_release_ip(struct ctdb_context *ctdb, 
				struct ctdb_req_control *c,
				TDB_DATA indata, 
				bool *async_reply)
{
	int ret;
	struct takeover_callback_state *state;
	struct ctdb_public_ip *pip = (struct ctdb_public_ip *)indata.dptr;
	struct ctdb_vnn *vnn;

	/* update our vnn list */
	vnn = find_public_ip_vnn(ctdb, &pip->addr);
	if (vnn == NULL) {
		DEBUG(DEBUG_INFO,("releaseip called for an ip '%s' that is not a public address\n",
			ctdb_addr_to_str(&pip->addr)));
		return 0;
	}
	vnn->pnn = pip->pnn;

	/* stop any previous arps */
	talloc_free(vnn->takeover_ctx);
	vnn->takeover_ctx = NULL;

	if (!ctdb_sys_have_ip(&pip->addr)) {
		DEBUG(DEBUG_DEBUG,("Redundant release of IP %s/%u on interface %s (ip not held)\n", 
			ctdb_addr_to_str(&pip->addr),
			vnn->public_netmask_bits, 
			ctdb_vnn_iface_string(vnn)));
		ctdb_vnn_unassign_iface(ctdb, vnn);
		return 0;
	}

	if (vnn->iface == NULL) {
		DEBUG(DEBUG_ERR,(__location__ " release_ip of IP %s is known to the kernel, "
				 "but we have no interface assigned, has someone manually configured it? Ignore for now.\n",
				 ctdb_addr_to_str(&vnn->public_address)));
		return 0;
	}

	DEBUG(DEBUG_NOTICE,("Release of IP %s/%u on interface %s  node:%d\n",
		ctdb_addr_to_str(&pip->addr),
		vnn->public_netmask_bits, 
		ctdb_vnn_iface_string(vnn),
		pip->pnn));

	state = talloc(ctdb, struct takeover_callback_state);
	CTDB_NO_MEMORY(ctdb, state);

	state->c = talloc_steal(state, c);
	state->addr = talloc(state, ctdb_sock_addr);       
	CTDB_NO_MEMORY(ctdb, state->addr);
	*state->addr = pip->addr;
	state->vnn   = vnn;

	ret = ctdb_event_script_callback(ctdb, 
					 state, release_ip_callback, state,
					 false,
					 CTDB_EVENT_RELEASE_IP,
					 "%s %s %u",
					 ctdb_vnn_iface_string(vnn),
					 ctdb_addr_to_str(&pip->addr),
					 vnn->public_netmask_bits);
	if (ret != 0) {
		DEBUG(DEBUG_ERR,(__location__ " Failed to release IP %s on interface %s\n",
			ctdb_addr_to_str(&pip->addr),
			ctdb_vnn_iface_string(vnn)));
		talloc_free(state);
		return -1;
	}

	/* tell the control that we will be reply asynchronously */
	*async_reply = true;
	return 0;
}

/*
  release an ip address old v4 style
 */
int32_t ctdb_control_release_ipv4(struct ctdb_context *ctdb, 
				struct ctdb_req_control *c,
				TDB_DATA indata, 
				bool *async_reply)
{
	TDB_DATA data;
	
	data.dsize = sizeof(struct ctdb_public_ip);
	data.dptr  = (uint8_t *)talloc_zero(c, struct ctdb_public_ip);
	CTDB_NO_MEMORY(ctdb, data.dptr);
	
	memcpy(data.dptr, indata.dptr, indata.dsize);
	return ctdb_control_release_ip(ctdb, c, data, async_reply);
}


static int ctdb_add_public_address(struct ctdb_context *ctdb,
				   ctdb_sock_addr *addr,
				   unsigned mask, const char *ifaces)
{
	struct ctdb_vnn      *vnn;
	uint32_t num = 0;
	char *tmp;
	const char *iface;
	int i;
	int ret;

	tmp = strdup(ifaces);
	for (iface = strtok(tmp, ","); iface; iface = strtok(NULL, ",")) {
		if (!ctdb_sys_check_iface_exists(iface)) {
			DEBUG(DEBUG_CRIT,("Interface %s does not exist. Can not add public-address : %s\n", iface, ctdb_addr_to_str(addr)));
			free(tmp);
			return -1;
		}
	}
	free(tmp);

	/* Verify that we dont have an entry for this ip yet */
	for (vnn=ctdb->vnn;vnn;vnn=vnn->next) {
		if (ctdb_same_sockaddr(addr, &vnn->public_address)) {
			DEBUG(DEBUG_CRIT,("Same ip '%s' specified multiple times in the public address list \n", 
				ctdb_addr_to_str(addr)));
			return -1;
		}		
	}

	/* create a new vnn structure for this ip address */
	vnn = talloc_zero(ctdb, struct ctdb_vnn);
	CTDB_NO_MEMORY_FATAL(ctdb, vnn);
	vnn->ifaces = talloc_array(vnn, const char *, num + 2);
	tmp = talloc_strdup(vnn, ifaces);
	CTDB_NO_MEMORY_FATAL(ctdb, tmp);
	for (iface = strtok(tmp, ","); iface; iface = strtok(NULL, ",")) {
		vnn->ifaces = talloc_realloc(vnn, vnn->ifaces, const char *, num + 2);
		CTDB_NO_MEMORY_FATAL(ctdb, vnn->ifaces);
		vnn->ifaces[num] = talloc_strdup(vnn, iface);
		CTDB_NO_MEMORY_FATAL(ctdb, vnn->ifaces[num]);
		num++;
	}
	talloc_free(tmp);
	vnn->ifaces[num] = NULL;
	vnn->public_address      = *addr;
	vnn->public_netmask_bits = mask;
	vnn->pnn                 = -1;
	if (ctdb_sys_have_ip(addr)) {
		DEBUG(DEBUG_ERR,("We are already hosting public address '%s'. setting PNN to ourself:%d\n", ctdb_addr_to_str(addr), ctdb->pnn));
		vnn->pnn = ctdb->pnn;
	}

	for (i=0; vnn->ifaces[i]; i++) {
		ret = ctdb_add_local_iface(ctdb, vnn->ifaces[i]);
		if (ret != 0) {
			DEBUG(DEBUG_CRIT, (__location__ " failed to add iface[%s] "
					   "for public_address[%s]\n",
					   vnn->ifaces[i], ctdb_addr_to_str(addr)));
			talloc_free(vnn);
			return -1;
		}
		if (i == 0) {
			vnn->iface = ctdb_find_iface(ctdb, vnn->ifaces[i]);
		}
	}

	DLIST_ADD(ctdb->vnn, vnn);

	return 0;
}

/*
  setup the event script directory
*/
int ctdb_set_event_script_dir(struct ctdb_context *ctdb, const char *script_dir)
{
	ctdb->event_script_dir = talloc_strdup(ctdb, script_dir);
	CTDB_NO_MEMORY(ctdb, ctdb->event_script_dir);
	return 0;
}

static void ctdb_check_interfaces_event(struct event_context *ev, struct timed_event *te, 
				  struct timeval t, void *private_data)
{
	struct ctdb_context *ctdb = talloc_get_type(private_data, 
							struct ctdb_context);
	struct ctdb_vnn *vnn;

	for (vnn=ctdb->vnn;vnn;vnn=vnn->next) {
		int i;

		for (i=0; vnn->ifaces[i] != NULL; i++) {
			if (!ctdb_sys_check_iface_exists(vnn->ifaces[i])) {
				DEBUG(DEBUG_CRIT,("Interface %s does not exist but is used by public ip %s\n",
					vnn->ifaces[i],
					ctdb_addr_to_str(&vnn->public_address)));
			}
		}
	}

	event_add_timed(ctdb->ev, ctdb->check_public_ifaces_ctx, 
		timeval_current_ofs(30, 0), 
		ctdb_check_interfaces_event, ctdb);
}


static int ctdb_start_monitoring_interfaces(struct ctdb_context *ctdb)
{
	if (ctdb->check_public_ifaces_ctx != NULL) {
		talloc_free(ctdb->check_public_ifaces_ctx);
		ctdb->check_public_ifaces_ctx = NULL;
	}

	ctdb->check_public_ifaces_ctx = talloc_new(ctdb);
	if (ctdb->check_public_ifaces_ctx == NULL) {
		ctdb_fatal(ctdb, "failed to allocate context for checking interfaces");
	}

	event_add_timed(ctdb->ev, ctdb->check_public_ifaces_ctx, 
		timeval_current_ofs(30, 0), 
		ctdb_check_interfaces_event, ctdb);

	return 0;
}


/*
  setup the public address lists from a file
*/
int ctdb_set_public_addresses(struct ctdb_context *ctdb, const char *alist)
{
	char **lines;
	int nlines;
	int i;

	lines = file_lines_load(alist, &nlines, ctdb);
	if (lines == NULL) {
		ctdb_set_error(ctdb, "Failed to load public address list '%s'\n", alist);
		return -1;
	}
	while (nlines > 0 && strcmp(lines[nlines-1], "") == 0) {
		nlines--;
	}

	for (i=0;i<nlines;i++) {
		unsigned mask;
		ctdb_sock_addr addr;
		const char *addrstr;
		const char *ifaces;
		char *tok, *line;

		line = lines[i];
		while ((*line == ' ') || (*line == '\t')) {
			line++;
		}
		if (*line == '#') {
			continue;
		}
		if (strcmp(line, "") == 0) {
			continue;
		}
		tok = strtok(line, " \t");
		addrstr = tok;
		tok = strtok(NULL, " \t");
		if (tok == NULL) {
			if (NULL == ctdb->default_public_interface) {
				DEBUG(DEBUG_CRIT,("No default public interface and no interface specified at line %u of public address list\n",
					 i+1));
				talloc_free(lines);
				return -1;
			}
			ifaces = ctdb->default_public_interface;
		} else {
			ifaces = tok;
		}

		if (!addrstr || !parse_ip_mask(addrstr, ifaces, &addr, &mask)) {
			DEBUG(DEBUG_CRIT,("Badly formed line %u in public address list\n", i+1));
			talloc_free(lines);
			return -1;
		}
		if (ctdb_add_public_address(ctdb, &addr, mask, ifaces)) {
			DEBUG(DEBUG_CRIT,("Failed to add line %u to the public address list\n", i+1));
			talloc_free(lines);
			return -1;
		}
	}


	ctdb_start_monitoring_interfaces(ctdb);

	talloc_free(lines);
	return 0;
}

int ctdb_set_single_public_ip(struct ctdb_context *ctdb,
			      const char *iface,
			      const char *ip)
{
	struct ctdb_vnn *svnn;
	struct ctdb_iface *cur = NULL;
	bool ok;
	int ret;

	svnn = talloc_zero(ctdb, struct ctdb_vnn);
	CTDB_NO_MEMORY(ctdb, svnn);

	svnn->ifaces = talloc_array(svnn, const char *, 2);
	CTDB_NO_MEMORY(ctdb, svnn->ifaces);
	svnn->ifaces[0] = talloc_strdup(svnn->ifaces, iface);
	CTDB_NO_MEMORY(ctdb, svnn->ifaces[0]);
	svnn->ifaces[1] = NULL;

	ok = parse_ip(ip, iface, 0, &svnn->public_address);
	if (!ok) {
		talloc_free(svnn);
		return -1;
	}

	ret = ctdb_add_local_iface(ctdb, svnn->ifaces[0]);
	if (ret != 0) {
		DEBUG(DEBUG_CRIT, (__location__ " failed to add iface[%s] "
				   "for single_ip[%s]\n",
				   svnn->ifaces[0],
				   ctdb_addr_to_str(&svnn->public_address)));
		talloc_free(svnn);
		return -1;
	}

	/* assume the single public ip interface is initially "good" */
	cur = ctdb_find_iface(ctdb, iface);
	if (cur == NULL) {
		DEBUG(DEBUG_CRIT,("Can not find public interface %s used by --single-public-ip", iface));
		return -1;
	}
	cur->link_up = true;

	ret = ctdb_vnn_assign_iface(ctdb, svnn);
	if (ret != 0) {
		talloc_free(svnn);
		return -1;
	}

	ctdb->single_ip_vnn = svnn;
	return 0;
}

/* Given a physical node, return the number of
   public addresses that is currently assigned to this node.
*/
static int node_ip_coverage(struct ctdb_context *ctdb, 
	int32_t pnn,
	struct ctdb_public_ip_list *ips)
{
	int num=0;

	for (;ips;ips=ips->next) {
		if (ips->pnn == pnn) {
			num++;
		}
	}
	return num;
}


/* Check if this is a public ip known to the node, i.e. can that
   node takeover this ip ?
*/
static int can_node_serve_ip(struct ctdb_context *ctdb, int32_t pnn, 
		struct ctdb_public_ip_list *ip)
{
	struct ctdb_all_public_ips *public_ips;
	int i;

	public_ips = ctdb->nodes[pnn]->available_public_ips;

	if (public_ips == NULL) {
		return -1;
	}

	for (i=0;i<public_ips->num;i++) {
		if (ctdb_same_ip(&ip->addr, &public_ips->ips[i].addr)) {
			/* yes, this node can serve this public ip */
			return 0;
		}
	}

	return -1;
}


/* search the node lists list for a node to takeover this ip.
   pick the node that currently are serving the least number of ips
   so that the ips get spread out evenly.
*/
static int find_takeover_node(struct ctdb_context *ctdb, 
		struct ctdb_node_map *nodemap, uint32_t mask, 
		struct ctdb_public_ip_list *ip,
		struct ctdb_public_ip_list *all_ips)
{
	int pnn, min=0, num;
	int i;

	pnn    = -1;
	for (i=0;i<nodemap->num;i++) {
		if (nodemap->nodes[i].flags & NODE_FLAGS_NOIPTAKEOVER) {
			/* This node is not allowed to takeover any addresses
			*/
			continue;
		}

		if (nodemap->nodes[i].flags & mask) {
			/* This node is not healty and can not be used to serve
			   a public address 
			*/
			continue;
		}

		/* verify that this node can serve this ip */
		if (can_node_serve_ip(ctdb, i, ip)) {
			/* no it couldnt   so skip to the next node */
			continue;
		}

		num = node_ip_coverage(ctdb, i, all_ips);
		/* was this the first node we checked ? */
		if (pnn == -1) {
			pnn = i;
			min  = num;
		} else {
			if (num < min) {
				pnn = i;
				min  = num;
			}
		}
	}	
	if (pnn == -1) {
		DEBUG(DEBUG_WARNING,(__location__ " Could not find node to take over public address '%s'\n",
			ctdb_addr_to_str(&ip->addr)));

		return -1;
	}

	ip->pnn = pnn;
	return 0;
}

#define IP_KEYLEN	4
static uint32_t *ip_key(ctdb_sock_addr *ip)
{
	static uint32_t key[IP_KEYLEN];

	bzero(key, sizeof(key));

	switch (ip->sa.sa_family) {
	case AF_INET:
		key[3]	= htonl(ip->ip.sin_addr.s_addr);
		break;
	case AF_INET6: {
		uint32_t *s6_a32 = (uint32_t *)&(ip->ip6.sin6_addr.s6_addr);
		key[0]	= htonl(s6_a32[0]);
		key[1]	= htonl(s6_a32[1]);
		key[2]	= htonl(s6_a32[2]);
		key[3]	= htonl(s6_a32[3]);
		break;
	}
	default:
		DEBUG(DEBUG_ERR, (__location__ " ERROR, unknown family passed :%u\n", ip->sa.sa_family));
		return key;
	}

	return key;
}

static void *add_ip_callback(void *parm, void *data)
{
	struct ctdb_public_ip_list *this_ip = parm; 
	struct ctdb_public_ip_list *prev_ip = data; 

	if (prev_ip == NULL) {
		return parm;
	}
	if (this_ip->pnn == -1) {
		this_ip->pnn = prev_ip->pnn;
	}

	return parm;
}

static int getips_count_callback(void *param, void *data)
{
	struct ctdb_public_ip_list **ip_list = (struct ctdb_public_ip_list **)param;
	struct ctdb_public_ip_list *new_ip = (struct ctdb_public_ip_list *)data;

	new_ip->next = *ip_list;
	*ip_list     = new_ip;
	return 0;
}

static struct ctdb_public_ip_list *
create_merged_ip_list(struct ctdb_context *ctdb)
{
	int i, j;
	struct ctdb_public_ip_list *ip_list;
	struct ctdb_all_public_ips *public_ips;

	if (ctdb->ip_tree != NULL) {
		talloc_free(ctdb->ip_tree);
		ctdb->ip_tree = NULL;
	}
	ctdb->ip_tree = trbt_create(ctdb, 0);

	for (i=0;i<ctdb->num_nodes;i++) {
		public_ips = ctdb->nodes[i]->known_public_ips;

		if (ctdb->nodes[i]->flags & NODE_FLAGS_DELETED) {
			continue;
		}

		/* there were no public ips for this node */
		if (public_ips == NULL) {
			continue;
		}		

		for (j=0;j<public_ips->num;j++) {
			struct ctdb_public_ip_list *tmp_ip; 

			tmp_ip = talloc_zero(ctdb->ip_tree, struct ctdb_public_ip_list);
			CTDB_NO_MEMORY_NULL(ctdb, tmp_ip);
			tmp_ip->pnn  = public_ips->ips[j].pnn;
			tmp_ip->addr = public_ips->ips[j].addr;
			tmp_ip->next = NULL;

			trbt_insertarray32_callback(ctdb->ip_tree,
				IP_KEYLEN, ip_key(&public_ips->ips[j].addr),
				add_ip_callback,
				tmp_ip);
		}
	}

	ip_list = NULL;
	trbt_traversearray32(ctdb->ip_tree, IP_KEYLEN, getips_count_callback, &ip_list);

	return ip_list;
}

/* 
 * This is the length of the longtest common prefix between the IPs.
 * It is calculated by XOR-ing the 2 IPs together and counting the
 * number of leading zeroes.  The implementation means that all
 * addresses end up being 128 bits long.
 *
 * FIXME? Should we consider IPv4 and IPv6 separately given that the
 * 12 bytes of 0 prefix padding will hurt the algorithm if there are
 * lots of nodes and IP addresses?
 */
static uint32_t ip_distance(ctdb_sock_addr *ip1, ctdb_sock_addr *ip2)
{
	uint32_t ip1_k[IP_KEYLEN];
	uint32_t *t;
	int i;
	uint32_t x;

	uint32_t distance = 0;

	memcpy(ip1_k, ip_key(ip1), sizeof(ip1_k));
	t = ip_key(ip2);
	for (i=0; i<IP_KEYLEN; i++) {
		x = ip1_k[i] ^ t[i];
		if (x == 0) {
			distance += 32;
		} else {
			/* Count number of leading zeroes. 
			 * FIXME? This could be optimised...
			 */
			while ((x & (1 << 31)) == 0) {
				x <<= 1;
				distance += 1;
			}
		}
	}

	return distance;
}

/* Calculate the IP distance for the given IP relative to IPs on the
   given node.  The ips argument is generally the all_ips variable
   used in the main part of the algorithm.
 */
static uint32_t ip_distance_2_sum(ctdb_sock_addr *ip,
				  struct ctdb_public_ip_list *ips,
				  int pnn)
{
	struct ctdb_public_ip_list *t;
	uint32_t d;

	uint32_t sum = 0;

	for (t=ips; t != NULL; t=t->next) {
		if (t->pnn != pnn) {
			continue;
		}

		/* Optimisation: We never calculate the distance
		 * between an address and itself.  This allows us to
		 * calculate the effect of removing an address from a
		 * node by simply calculating the distance between
		 * that address and all of the exitsing addresses.
		 * Moreover, we assume that we're only ever dealing
		 * with addresses from all_ips so we can identify an
		 * address via a pointer rather than doing a more
		 * expensive address comparison. */
		if (&(t->addr) == ip) {
			continue;
		}

		d = ip_distance(ip, &(t->addr));
		sum += d * d;  /* Cheaper than pulling in math.h :-) */
	}

	return sum;
}

/* Return the LCP2 imbalance metric for addresses currently assigned
   to the given node.
 */
static uint32_t lcp2_imbalance(struct ctdb_public_ip_list * all_ips, int pnn)
{
	struct ctdb_public_ip_list *t;

	uint32_t imbalance = 0;

	for (t=all_ips; t!=NULL; t=t->next) {
		if (t->pnn != pnn) {
			continue;
		}
		/* Pass the rest of the IPs rather than the whole
		   all_ips input list.
		*/
		imbalance += ip_distance_2_sum(&(t->addr), t->next, pnn);
	}

	return imbalance;
}

/* Allocate any unassigned IPs just by looping through the IPs and
 * finding the best node for each.
 */
static void basic_allocate_unassigned(struct ctdb_context *ctdb,
				      struct ctdb_node_map *nodemap,
				      uint32_t mask,
				      struct ctdb_public_ip_list *all_ips)
{
	struct ctdb_public_ip_list *tmp_ip;

	/* loop over all ip's and find a physical node to cover for 
	   each unassigned ip.
	*/
	for (tmp_ip=all_ips;tmp_ip;tmp_ip=tmp_ip->next) {
		if (tmp_ip->pnn == -1) {
			if (find_takeover_node(ctdb, nodemap, mask, tmp_ip, all_ips)) {
				DEBUG(DEBUG_WARNING,("Failed to find node to cover ip %s\n",
					ctdb_addr_to_str(&tmp_ip->addr)));
			}
		}
	}
}

/* Basic non-deterministic rebalancing algorithm.
 */
static bool basic_failback(struct ctdb_context *ctdb,
			   struct ctdb_node_map *nodemap,
			   uint32_t mask,
			   struct ctdb_public_ip_list *all_ips,
			   int num_ips,
			   int *retries)
{
	int i;
	int maxnode, maxnum=0, minnode, minnum=0, num;
	struct ctdb_public_ip_list *tmp_ip;

	/* for each ip address, loop over all nodes that can serve
	   this ip and make sure that the difference between the node
	   serving the most and the node serving the least ip's are
	   not greater than 1.
	*/
	for (tmp_ip=all_ips;tmp_ip;tmp_ip=tmp_ip->next) {
		if (tmp_ip->pnn == -1) {
			continue;
		}

		/* Get the highest and lowest number of ips's served by any 
		   valid node which can serve this ip.
		*/
		maxnode = -1;
		minnode = -1;
		for (i=0;i<nodemap->num;i++) {
			if (nodemap->nodes[i].flags & mask) {
				continue;
			}

			/* Only check nodes that are allowed to takeover an ip */
			if (nodemap->nodes[i].flags & NODE_FLAGS_NOIPTAKEOVER) {
				continue;
			}

			/* only check nodes that can actually serve this ip */
			if (can_node_serve_ip(ctdb, i, tmp_ip)) {
				/* no it couldnt   so skip to the next node */
				continue;
			}

			num = node_ip_coverage(ctdb, i, all_ips);
			if (maxnode == -1) {
				maxnode = i;
				maxnum  = num;
			} else {
				if (num > maxnum) {
					maxnode = i;
					maxnum  = num;
				}
			}
			if (minnode == -1) {
				minnode = i;
				minnum  = num;
			} else {
				if (num < minnum) {
					minnode = i;
					minnum  = num;
				}
			}
		}
		if (maxnode == -1) {
			DEBUG(DEBUG_WARNING,(__location__ " Could not find maxnode. May not be able to serve ip '%s'\n",
				ctdb_addr_to_str(&tmp_ip->addr)));

			continue;
		}

		/* If we want deterministic IPs then dont try to reallocate 
		   them to spread out the load.
		*/
		if (1 == ctdb->tunable.deterministic_public_ips) {
			continue;
		}

		/* if the spread between the smallest and largest coverage by
		   a node is >=2 we steal one of the ips from the node with
		   most coverage to even things out a bit.
		   try to do this a limited number of times since we dont
		   want to spend too much time balancing the ip coverage.
		*/
		if ( (maxnum > minnum+1)
		     && (*retries < (num_ips + 5)) ){
			struct ctdb_public_ip_list *tmp;

			/* mark one of maxnode's vnn's as unassigned and try
			   again
			*/
			for (tmp=all_ips;tmp;tmp=tmp->next) {
				if (tmp->pnn == maxnode) {
					tmp->pnn = -1;
					(*retries)++;
					return true;
				}
			}
		}
	}

	return false;
}

struct ctdb_rebalancenodes {
	struct ctdb_rebalancenodes *next;
	uint32_t pnn;
};
static struct ctdb_rebalancenodes *force_rebalance_list = NULL;


/* set this flag to force the node to be rebalanced even if it just didnt
   become healthy again.
*/
void lcp2_forcerebalance(struct ctdb_context *ctdb, uint32_t pnn)
{
	struct ctdb_rebalancenodes *rebalance;

	for (rebalance = force_rebalance_list; rebalance; rebalance = rebalance->next) {
		if (rebalance->pnn == pnn) {
			return;
		}
	}

	rebalance = talloc(ctdb, struct ctdb_rebalancenodes);
	rebalance->pnn = pnn;
	rebalance->next = force_rebalance_list;
	force_rebalance_list = rebalance;
}

/* Do necessary LCP2 initialisation.  Bury it in a function here so
 * that we can unit test it.
 */
static void lcp2_init(struct ctdb_context * tmp_ctx,
	       struct ctdb_node_map * nodemap,
	       uint32_t mask,
	       struct ctdb_public_ip_list *all_ips,
	       uint32_t **lcp2_imbalances,
	       bool **newly_healthy)
{
	int i;
	struct ctdb_public_ip_list *tmp_ip;

	*newly_healthy = talloc_array(tmp_ctx, bool, nodemap->num);
	CTDB_NO_MEMORY_FATAL(tmp_ctx, *newly_healthy);
	*lcp2_imbalances = talloc_array(tmp_ctx, uint32_t, nodemap->num);
	CTDB_NO_MEMORY_FATAL(tmp_ctx, *lcp2_imbalances);

	for (i=0;i<nodemap->num;i++) {
		(*lcp2_imbalances)[i] = lcp2_imbalance(all_ips, i);
		/* First step: is the node "healthy"? */
		(*newly_healthy)[i] = ! (bool)(nodemap->nodes[i].flags & mask);
	}

	/* 2nd step: if a ndoe has IPs assigned then it must have been
	 * healthy before, so we remove it from consideration... */
	for (tmp_ip=all_ips;tmp_ip;tmp_ip=tmp_ip->next) {
		if (tmp_ip->pnn != -1) {
			(*newly_healthy)[tmp_ip->pnn] = false;
		}
	}

	/* 3rd step: if a node is forced to re-balance then
	   we allow failback onto the node */
	while (force_rebalance_list != NULL) {
		struct ctdb_rebalancenodes *next = force_rebalance_list->next;

		if (force_rebalance_list->pnn <= nodemap->num) {
			(*newly_healthy)[force_rebalance_list->pnn] = true;
		}

		DEBUG(DEBUG_ERR,("During ipreallocation, forced rebalance of node %d\n", force_rebalance_list->pnn));
		talloc_free(force_rebalance_list);
		force_rebalance_list = next;
	}
}

/* Allocate any unassigned addresses using the LCP2 algorithm to find
 * the IP/node combination that will cost the least.
 */
static void lcp2_allocate_unassigned(struct ctdb_context *ctdb,
			      struct ctdb_node_map *nodemap,
			      uint32_t mask,
			      struct ctdb_public_ip_list *all_ips,
			      uint32_t *lcp2_imbalances)
{
	struct ctdb_public_ip_list *tmp_ip;
	int dstnode;

	int minnode;
	uint32_t mindsum, dstdsum, dstimbl, minimbl;
	struct ctdb_public_ip_list *minip;

	bool should_loop = true;
	bool have_unassigned = true;

	while (have_unassigned && should_loop) {
		should_loop = false;

		DEBUG(DEBUG_DEBUG,(" ----------------------------------------\n"));
		DEBUG(DEBUG_DEBUG,(" CONSIDERING MOVES (UNASSIGNED)\n"));

		minnode = -1;
		mindsum = 0;
		minip = NULL;

		/* loop over each unassigned ip. */
		for (tmp_ip=all_ips;tmp_ip;tmp_ip=tmp_ip->next) {
			if (tmp_ip->pnn != -1) {
				continue;
			}

			for (dstnode=0; dstnode < nodemap->num; dstnode++) {
				/* Only check nodes that are allowed to takeover an ip */
				if (nodemap->nodes[dstnode].flags & NODE_FLAGS_NOIPTAKEOVER) {
					continue;
				}

				/* only check nodes that can actually serve this ip */
				if (can_node_serve_ip(ctdb, dstnode, tmp_ip)) {
					/* no it couldnt   so skip to the next node */
					continue;
				}
				if (nodemap->nodes[dstnode].flags & mask) {
					continue;
				}

				dstdsum = ip_distance_2_sum(&(tmp_ip->addr), all_ips, dstnode);
				dstimbl = lcp2_imbalances[dstnode] + dstdsum;
				DEBUG(DEBUG_DEBUG,(" %s -> %d [+%d]\n",
						   ctdb_addr_to_str(&(tmp_ip->addr)),
						   dstnode,
						   dstimbl - lcp2_imbalances[dstnode]));


				if ((minnode == -1) || (dstdsum < mindsum)) {
					minnode = dstnode;
					minimbl = dstimbl;
					mindsum = dstdsum;
					minip = tmp_ip;
					should_loop = true;
				}
			}
		}

		DEBUG(DEBUG_DEBUG,(" ----------------------------------------\n"));

		/* If we found one then assign it to the given node. */
		if (minnode != -1) {
			minip->pnn = minnode;
			lcp2_imbalances[minnode] = minimbl;
			DEBUG(DEBUG_INFO,(" %s -> %d [+%d]\n",
					  ctdb_addr_to_str(&(minip->addr)),
					  minnode,
					  mindsum));
		}

		/* There might be a better way but at least this is clear. */
		have_unassigned = false;
		for (tmp_ip=all_ips;tmp_ip;tmp_ip=tmp_ip->next) {
			if (tmp_ip->pnn == -1) {
				have_unassigned = true;
			}
		}
	}

	/* We know if we have an unassigned addresses so we might as
	 * well optimise.
	 */
	if (have_unassigned) {
		for (tmp_ip=all_ips;tmp_ip;tmp_ip=tmp_ip->next) {
			if (tmp_ip->pnn == -1) {
				DEBUG(DEBUG_WARNING,("Failed to find node to cover ip %s\n",
						     ctdb_addr_to_str(&tmp_ip->addr)));
			}
		}
	}
}

/* LCP2 algorithm for rebalancing the cluster.  Given a candidate node
 * to move IPs from, determines the best IP/destination node
 * combination to move from the source node.
 */
static bool lcp2_failback_candidate(struct ctdb_context *ctdb,
				    struct ctdb_node_map *nodemap,
				    struct ctdb_public_ip_list *all_ips,
				    int srcnode,
				    uint32_t candimbl,
				    uint32_t *lcp2_imbalances,
				    bool *newly_healthy)
{
	int dstnode, mindstnode;
	uint32_t srcimbl, srcdsum, dstimbl, dstdsum;
	uint32_t minsrcimbl, mindstimbl;
	struct ctdb_public_ip_list *minip;
	struct ctdb_public_ip_list *tmp_ip;

	/* Find an IP and destination node that best reduces imbalance. */
	minip = NULL;
	minsrcimbl = 0;
	mindstnode = -1;
	mindstimbl = 0;

	DEBUG(DEBUG_DEBUG,(" ----------------------------------------\n"));
	DEBUG(DEBUG_DEBUG,(" CONSIDERING MOVES FROM %d [%d]\n", srcnode, candimbl));

	for (tmp_ip=all_ips; tmp_ip; tmp_ip=tmp_ip->next) {
		/* Only consider addresses on srcnode. */
		if (tmp_ip->pnn != srcnode) {
			continue;
		}

		/* What is this IP address costing the source node? */
		srcdsum = ip_distance_2_sum(&(tmp_ip->addr), all_ips, srcnode);
		srcimbl = candimbl - srcdsum;

		/* Consider this IP address would cost each potential
		 * destination node.  Destination nodes are limited to
		 * those that are newly healthy, since we don't want
		 * to do gratuitous failover of IPs just to make minor
		 * balance improvements.
		 */
		for (dstnode=0; dstnode < nodemap->num; dstnode++) {
			if (! newly_healthy[dstnode]) {
				continue;
			}

			/* Only check nodes that are allowed to takeover an ip */
			if (nodemap->nodes[dstnode].flags & NODE_FLAGS_NOIPTAKEOVER) {
				continue;
			}

			/* only check nodes that can actually serve this ip */
			if (can_node_serve_ip(ctdb, dstnode, tmp_ip)) {
				/* no it couldnt   so skip to the next node */
				continue;
			}

			dstdsum = ip_distance_2_sum(&(tmp_ip->addr), all_ips, dstnode);
			dstimbl = lcp2_imbalances[dstnode] + dstdsum;
			DEBUG(DEBUG_DEBUG,(" %d [%d] -> %s -> %d [+%d]\n",
					   srcnode, srcimbl - lcp2_imbalances[srcnode],
					   ctdb_addr_to_str(&(tmp_ip->addr)),
					   dstnode, dstimbl - lcp2_imbalances[dstnode]));

			if ((dstimbl < candimbl) && (dstdsum < srcdsum) && \
			    ((mindstnode == -1) ||				\
			     ((srcimbl + dstimbl) < (minsrcimbl + mindstimbl)))) {

				minip = tmp_ip;
				minsrcimbl = srcimbl;
				mindstnode = dstnode;
				mindstimbl = dstimbl;
			}
		}
	}
	DEBUG(DEBUG_DEBUG,(" ----------------------------------------\n"));

        if (mindstnode != -1) {
		/* We found a move that makes things better... */
		DEBUG(DEBUG_INFO,("%d [%d] -> %s -> %d [+%d]\n",
				  srcnode, minsrcimbl - lcp2_imbalances[srcnode],
				  ctdb_addr_to_str(&(minip->addr)),
				  mindstnode, mindstimbl - lcp2_imbalances[mindstnode]));


		lcp2_imbalances[srcnode] = srcimbl;
		lcp2_imbalances[mindstnode] = mindstimbl;
		minip->pnn = mindstnode;

		return true;
	}

        return false;
	
}

struct lcp2_imbalance_pnn {
	uint32_t imbalance;
	int pnn;
};

static int lcp2_cmp_imbalance_pnn(const void * a, const void * b)
{
	const struct lcp2_imbalance_pnn * lipa = (const struct lcp2_imbalance_pnn *) a;
	const struct lcp2_imbalance_pnn * lipb = (const struct lcp2_imbalance_pnn *) b;

	if (lipa->imbalance > lipb->imbalance) {
		return -1;
	} else if (lipa->imbalance == lipb->imbalance) {
		return 0;
	} else {
		return 1;
	}
}

/* LCP2 algorithm for rebalancing the cluster.  This finds the source
 * node with the highest LCP2 imbalance, and then determines the best
 * IP/destination node combination to move from the source node.
 */
static bool lcp2_failback(struct ctdb_context *ctdb,
			  struct ctdb_node_map *nodemap,
			  uint32_t mask,
			  struct ctdb_public_ip_list *all_ips,
			  uint32_t *lcp2_imbalances,
			  bool *newly_healthy)
{
	int i, num_newly_healthy;
	struct lcp2_imbalance_pnn * lips;
	bool ret;

	/* It is only worth continuing if we have suitable target
	 * nodes to transfer IPs to.  This check is much cheaper than
	 * continuing on...
	 */
	num_newly_healthy = 0;
	for (i = 0; i < nodemap->num; i++) {
		if (newly_healthy[i]) {
			num_newly_healthy++;
		}
	}
	if (num_newly_healthy == 0) {
		return false;
	}

	/* Put the imbalances and nodes into an array, sort them and
	 * iterate through candidates.  Usually the 1st one will be
	 * used, so this doesn't cost much...
	 */
	lips = talloc_array(ctdb, struct lcp2_imbalance_pnn, nodemap->num);
	for (i = 0; i < nodemap->num; i++) {
		lips[i].imbalance = lcp2_imbalances[i];
		lips[i].pnn = i;
	}
	qsort(lips, nodemap->num, sizeof(struct lcp2_imbalance_pnn),
	      lcp2_cmp_imbalance_pnn);

	ret = false;
	for (i = 0; i < nodemap->num; i++) {
		/* This means that all nodes had 0 or 1 addresses, so
		 * can't be imbalanced.
		 */
		if (lips[i].imbalance == 0) {
			break;
		}

		if (lcp2_failback_candidate(ctdb,
					    nodemap,
					    all_ips,
					    lips[i].pnn,
					    lips[i].imbalance,
					    lcp2_imbalances,
					    newly_healthy)) {
			ret = true;
			break;
		}
	}

	talloc_free(lips);
	return ret;
}

/* The calculation part of the IP allocation algorithm. */
static void ctdb_takeover_run_core(struct ctdb_context *ctdb,
				   struct ctdb_node_map *nodemap,
				   struct ctdb_public_ip_list **all_ips_p)
{
	int i, num_healthy, retries, num_ips;
	uint32_t mask;
	struct ctdb_public_ip_list *all_ips, *tmp_ip;
	uint32_t *lcp2_imbalances;
	bool *newly_healthy;

	TALLOC_CTX *tmp_ctx = talloc_new(ctdb);

	/* Count how many completely healthy nodes we have */
	num_healthy = 0;
	for (i=0;i<nodemap->num;i++) {
		if (!(nodemap->nodes[i].flags & (NODE_FLAGS_INACTIVE|NODE_FLAGS_DISABLED))) {
			num_healthy++;
		}
	}

	if (num_healthy > 0) {
		/* We have healthy nodes, so only consider them for 
		   serving public addresses
		*/
		mask = NODE_FLAGS_INACTIVE|NODE_FLAGS_DISABLED;
	} else {
		/* We didnt have any completely healthy nodes so
		   use "disabled" nodes as a fallback
		*/
		mask = NODE_FLAGS_INACTIVE;
	}

	/* since nodes only know about those public addresses that
	   can be served by that particular node, no single node has
	   a full list of all public addresses that exist in the cluster.
	   Walk over all node structures and create a merged list of
	   all public addresses that exist in the cluster.

	   keep the tree of ips around as ctdb->ip_tree
	*/
	all_ips = create_merged_ip_list(ctdb);
	*all_ips_p = all_ips; /* minimal code changes */

	/* Count how many ips we have */
	num_ips = 0;
	for (tmp_ip=all_ips;tmp_ip;tmp_ip=tmp_ip->next) {
		num_ips++;
	}

	/* If we want deterministic ip allocations, i.e. that the ip addresses
	   will always be allocated the same way for a specific set of
	   available/unavailable nodes.
	*/
	if (1 == ctdb->tunable.deterministic_public_ips) {		
		DEBUG(DEBUG_NOTICE,("Deterministic IPs enabled. Resetting all ip allocations\n"));
		for (i=0,tmp_ip=all_ips;tmp_ip;tmp_ip=tmp_ip->next,i++) {
			tmp_ip->pnn = i%nodemap->num;
		}
	}


	/* mark all public addresses with a masked node as being served by
	   node -1
	*/
	for (tmp_ip=all_ips;tmp_ip;tmp_ip=tmp_ip->next) {
		if (tmp_ip->pnn == -1) {
			continue;
		}
		if (nodemap->nodes[tmp_ip->pnn].flags & mask) {
			tmp_ip->pnn = -1;
		}
	}

	/* verify that the assigned nodes can serve that public ip
	   and set it to -1 if not
	*/
	for (tmp_ip=all_ips;tmp_ip;tmp_ip=tmp_ip->next) {
		if (tmp_ip->pnn == -1) {
			continue;
		}
		if (can_node_serve_ip(ctdb, tmp_ip->pnn, tmp_ip) != 0) {
			/* this node can not serve this ip. */
			tmp_ip->pnn = -1;
		}
	}

        if (1 == ctdb->tunable.lcp2_public_ip_assignment) {
		lcp2_init(tmp_ctx, nodemap, mask, all_ips, &lcp2_imbalances, &newly_healthy);
	}

	/* now we must redistribute all public addresses with takeover node
	   -1 among the nodes available
	*/
	retries = 0;
try_again:
	if (1 == ctdb->tunable.lcp2_public_ip_assignment) {
		lcp2_allocate_unassigned(ctdb, nodemap, mask, all_ips, lcp2_imbalances);
	} else {
		basic_allocate_unassigned(ctdb, nodemap, mask, all_ips);
	}

	/* If we dont want ips to fail back after a node becomes healthy
	   again, we wont even try to reallocat the ip addresses so that
	   they are evenly spread out.
	   This can NOT be used at the same time as DeterministicIPs !
	*/
	if (1 == ctdb->tunable.no_ip_failback) {
		if (1 == ctdb->tunable.deterministic_public_ips) {
			DEBUG(DEBUG_ERR, ("ERROR: You can not use 'DeterministicIPs' and 'NoIPFailback' at the same time\n"));
		}
		goto finished;
	}


	/* now, try to make sure the ip adresses are evenly distributed
	   across the node.
	*/
	if (1 == ctdb->tunable.lcp2_public_ip_assignment) {
		if (lcp2_failback(ctdb, nodemap, mask, all_ips, lcp2_imbalances, newly_healthy)) {
			goto try_again;
		}
	} else {
		if (basic_failback(ctdb, nodemap, mask, all_ips, num_ips, &retries)) {
			goto try_again;
		}
	}

	/* finished distributing the public addresses, now just send the 
	   info out to the nodes */
finished:
	/* at this point ->pnn is the node which will own each IP
	   or -1 if there is no node that can cover this ip
	*/

	return;
}

static void noiptakeover_cb(struct ctdb_context *ctdb, uint32_t pnn, int32_t res, TDB_DATA outdata, void *callback)
{
	struct ctdb_node_map *nodemap = (struct ctdb_node_map *)callback;

	if (res != 0) {
		DEBUG(DEBUG_ERR,("Failure to read NoIPTakeover tunable from remote node %d\n", pnn));
		return;
	}

	if (outdata.dsize != sizeof(uint32_t)) {
		DEBUG(DEBUG_ERR,("Wrong size of returned data when reading NoIPTakeover tunable from node %d. Expected %d bytes but received %d bytes\n", pnn, (int)sizeof(uint32_t), (int)outdata.dsize));
		return;
	}

	if (pnn >= nodemap->num) {
		DEBUG(DEBUG_ERR,("Got NoIPTakeover reply from node %d but nodemap only has %d entries\n", pnn, nodemap->num));
		return;
	}

	if (*(uint32_t *)outdata.dptr != 0) {
		nodemap->nodes[pnn].flags |= NODE_FLAGS_NOIPTAKEOVER;
	}
}

/*
  make any IP alias changes for public addresses that are necessary 
 */
int ctdb_takeover_run(struct ctdb_context *ctdb, struct ctdb_node_map *nodemap)
{
	int i;
	struct ctdb_public_ip ip;
	struct ctdb_public_ipv4 ipv4;
	struct ctdb_control_get_tunable *t;
	uint32_t *nodes;
	struct ctdb_public_ip_list *all_ips, *tmp_ip;
	TDB_DATA data;
	struct timeval timeout;
	struct client_async_data *async_data;
	struct ctdb_client_control_state *state;
	TALLOC_CTX *tmp_ctx = talloc_new(ctdb);

	/*
	 * ip failover is completely disabled, just send out the 
	 * ipreallocated event.
	 */
	if (ctdb->tunable.disable_ip_failover != 0) {
		goto ipreallocated;
	}


	/* assume all nodes do support failback */
	for (i=0;i<nodemap->num;i++) {
		nodemap->nodes[i].flags &= ~NODE_FLAGS_NOIPTAKEOVER;
	}
	data.dsize = offsetof(struct ctdb_control_get_tunable, name) + strlen("NoIPTakeover") + 1;
	data.dptr  = talloc_size(tmp_ctx, data.dsize);
	t = (struct ctdb_control_get_tunable *)data.dptr;
	t->length = strlen("NoIPTakeover")+1;
	memcpy(t->name, "NoIPTakeover", t->length);
	nodes = list_of_connected_nodes(ctdb, nodemap, tmp_ctx, true);
	if (ctdb_client_async_control(ctdb, CTDB_CONTROL_GET_TUNABLE,
				      nodes, 0, TAKEOVER_TIMEOUT(),
				      false, data,
				      noiptakeover_cb, NULL,
				      nodemap) != 0) {
		DEBUG(DEBUG_ERR, (__location__ " ctdb_control to get noiptakeover tunable failed\n"));
	}
	talloc_free(nodes);
	talloc_free(data.dptr);


	ZERO_STRUCT(ip);

	/* Do the IP reassignment calculations */
	ctdb_takeover_run_core(ctdb, nodemap, &all_ips);

	/* now tell all nodes to delete any alias that they should not
	   have.  This will be a NOOP on nodes that don't currently
	   hold the given alias */
	async_data = talloc_zero(tmp_ctx, struct client_async_data);
	CTDB_NO_MEMORY_FATAL(ctdb, async_data);

	for (i=0;i<nodemap->num;i++) {
		/* don't talk to unconnected nodes, but do talk to banned nodes */
		if (nodemap->nodes[i].flags & NODE_FLAGS_DISCONNECTED) {
			continue;
		}

		for (tmp_ip=all_ips;tmp_ip;tmp_ip=tmp_ip->next) {
			if (tmp_ip->pnn == nodemap->nodes[i].pnn) {
				/* This node should be serving this
				   vnn so dont tell it to release the ip
				*/
				continue;
			}
			if (tmp_ip->addr.sa.sa_family == AF_INET) {
				ipv4.pnn = tmp_ip->pnn;
				ipv4.sin = tmp_ip->addr.ip;

				timeout = TAKEOVER_TIMEOUT();
				data.dsize = sizeof(ipv4);
				data.dptr  = (uint8_t *)&ipv4;
				state = ctdb_control_send(ctdb, nodemap->nodes[i].pnn,
						0, CTDB_CONTROL_RELEASE_IPv4, 0,
						data, async_data,
						&timeout, NULL);
			} else {
				ip.pnn  = tmp_ip->pnn;
				ip.addr = tmp_ip->addr;

				timeout = TAKEOVER_TIMEOUT();
				data.dsize = sizeof(ip);
				data.dptr  = (uint8_t *)&ip;
				state = ctdb_control_send(ctdb, nodemap->nodes[i].pnn,
						0, CTDB_CONTROL_RELEASE_IP, 0,
						data, async_data,
						&timeout, NULL);
			}

			if (state == NULL) {
				DEBUG(DEBUG_ERR,(__location__ " Failed to call async control CTDB_CONTROL_RELEASE_IP to node %u\n", nodemap->nodes[i].pnn));
				talloc_free(tmp_ctx);
				return -1;
			}
		
			ctdb_client_async_add(async_data, state);
		}
	}
	if (ctdb_client_async_wait(ctdb, async_data) != 0) {
		DEBUG(DEBUG_ERR,(__location__ " Async control CTDB_CONTROL_RELEASE_IP failed\n"));
		talloc_free(tmp_ctx);
		return -1;
	}
	talloc_free(async_data);


	/* tell all nodes to get their own IPs */
	async_data = talloc_zero(tmp_ctx, struct client_async_data);
	CTDB_NO_MEMORY_FATAL(ctdb, async_data);
	for (tmp_ip=all_ips;tmp_ip;tmp_ip=tmp_ip->next) {
		if (tmp_ip->pnn == -1) {
			/* this IP won't be taken over */
			continue;
		}

		if (tmp_ip->addr.sa.sa_family == AF_INET) {
			ipv4.pnn = tmp_ip->pnn;
			ipv4.sin = tmp_ip->addr.ip;

			timeout = TAKEOVER_TIMEOUT();
			data.dsize = sizeof(ipv4);
			data.dptr  = (uint8_t *)&ipv4;
			state = ctdb_control_send(ctdb, tmp_ip->pnn,
					0, CTDB_CONTROL_TAKEOVER_IPv4, 0,
					data, async_data,
					&timeout, NULL);
		} else {
			ip.pnn  = tmp_ip->pnn;
			ip.addr = tmp_ip->addr;

			timeout = TAKEOVER_TIMEOUT();
			data.dsize = sizeof(ip);
			data.dptr  = (uint8_t *)&ip;
			state = ctdb_control_send(ctdb, tmp_ip->pnn,
					0, CTDB_CONTROL_TAKEOVER_IP, 0,
					data, async_data,
					&timeout, NULL);
		}
		if (state == NULL) {
			DEBUG(DEBUG_ERR,(__location__ " Failed to call async control CTDB_CONTROL_TAKEOVER_IP to node %u\n", tmp_ip->pnn));
			talloc_free(tmp_ctx);
			return -1;
		}
		
		ctdb_client_async_add(async_data, state);
	}
	if (ctdb_client_async_wait(ctdb, async_data) != 0) {
		DEBUG(DEBUG_ERR,(__location__ " Async control CTDB_CONTROL_TAKEOVER_IP failed\n"));
		talloc_free(tmp_ctx);
		return -1;
	}

ipreallocated:
	/* tell all nodes to update natwg */
	/* send the flags update natgw on all connected nodes */
	data.dptr  = discard_const("ipreallocated");
	data.dsize = strlen((char *)data.dptr) + 1; 
	nodes = list_of_connected_nodes(ctdb, nodemap, tmp_ctx, true);
	if (ctdb_client_async_control(ctdb, CTDB_CONTROL_RUN_EVENTSCRIPTS,
				      nodes, 0, TAKEOVER_TIMEOUT(),
				      false, data,
				      NULL, NULL,
				      NULL) != 0) {
		DEBUG(DEBUG_ERR, (__location__ " ctdb_control to updatenatgw failed\n"));
	}

	talloc_free(tmp_ctx);
	return 0;
}


/*
  destroy a ctdb_client_ip structure
 */
static int ctdb_client_ip_destructor(struct ctdb_client_ip *ip)
{
	DEBUG(DEBUG_DEBUG,("destroying client tcp for %s:%u (client_id %u)\n",
		ctdb_addr_to_str(&ip->addr),
		ntohs(ip->addr.ip.sin_port),
		ip->client_id));

	DLIST_REMOVE(ip->ctdb->client_ip_list, ip);
	return 0;
}

/*
  called by a client to inform us of a TCP connection that it is managing
  that should tickled with an ACK when IP takeover is done
  we handle both the old ipv4 style of packets as well as the new ipv4/6
  pdus.
 */
int32_t ctdb_control_tcp_client(struct ctdb_context *ctdb, uint32_t client_id,
				TDB_DATA indata)
{
	struct ctdb_client *client = ctdb_reqid_find(ctdb, client_id, struct ctdb_client);
	struct ctdb_control_tcp *old_addr = NULL;
	struct ctdb_control_tcp_addr new_addr;
	struct ctdb_control_tcp_addr *tcp_sock = NULL;
	struct ctdb_tcp_list *tcp;
	struct ctdb_tcp_connection t;
	int ret;
	TDB_DATA data;
	struct ctdb_client_ip *ip;
	struct ctdb_vnn *vnn;
	ctdb_sock_addr addr;

	switch (indata.dsize) {
	case sizeof(struct ctdb_control_tcp):
		old_addr = (struct ctdb_control_tcp *)indata.dptr;
		ZERO_STRUCT(new_addr);
		tcp_sock = &new_addr;
		tcp_sock->src.ip  = old_addr->src;
		tcp_sock->dest.ip = old_addr->dest;
		break;
	case sizeof(struct ctdb_control_tcp_addr):
		tcp_sock = (struct ctdb_control_tcp_addr *)indata.dptr;
		break;
	default:
		DEBUG(DEBUG_ERR,(__location__ " Invalid data structure passed "
				 "to ctdb_control_tcp_client. size was %d but "
				 "only allowed sizes are %lu and %lu\n",
				 (int)indata.dsize,
				 (long unsigned)sizeof(struct ctdb_control_tcp),
				 (long unsigned)sizeof(struct ctdb_control_tcp_addr)));
		return -1;
	}

	addr = tcp_sock->src;
	ctdb_canonicalize_ip(&addr,  &tcp_sock->src);
	addr = tcp_sock->dest;
	ctdb_canonicalize_ip(&addr, &tcp_sock->dest);

	ZERO_STRUCT(addr);
	memcpy(&addr, &tcp_sock->dest, sizeof(addr));
	vnn = find_public_ip_vnn(ctdb, &addr);
	if (vnn == NULL) {
		switch (addr.sa.sa_family) {
		case AF_INET:
			if (ntohl(addr.ip.sin_addr.s_addr) != INADDR_LOOPBACK) {
				DEBUG(DEBUG_ERR,("Could not add client IP %s. This is not a public address.\n", 
					ctdb_addr_to_str(&addr)));
			}
			break;
		case AF_INET6:
			DEBUG(DEBUG_ERR,("Could not add client IP %s. This is not a public ipv6 address.\n", 
				ctdb_addr_to_str(&addr)));
			break;
		default:
			DEBUG(DEBUG_ERR,(__location__ " Unknown family type %d\n", addr.sa.sa_family));
		}

		return 0;
	}

	if (vnn->pnn != ctdb->pnn) {
		DEBUG(DEBUG_ERR,("Attempt to register tcp client for IP %s we don't hold - failing (client_id %u pid %u)\n",
			ctdb_addr_to_str(&addr),
			client_id, client->pid));
		/* failing this call will tell smbd to die */
		return -1;
	}

	ip = talloc(client, struct ctdb_client_ip);
	CTDB_NO_MEMORY(ctdb, ip);

	ip->ctdb      = ctdb;
	ip->addr      = addr;
	ip->client_id = client_id;
	talloc_set_destructor(ip, ctdb_client_ip_destructor);
	DLIST_ADD(ctdb->client_ip_list, ip);

	tcp = talloc(client, struct ctdb_tcp_list);
	CTDB_NO_MEMORY(ctdb, tcp);

	tcp->connection.src_addr = tcp_sock->src;
	tcp->connection.dst_addr = tcp_sock->dest;

	DLIST_ADD(client->tcp_list, tcp);

	t.src_addr = tcp_sock->src;
	t.dst_addr = tcp_sock->dest;

	data.dptr = (uint8_t *)&t;
	data.dsize = sizeof(t);

	switch (addr.sa.sa_family) {
	case AF_INET:
		DEBUG(DEBUG_INFO,("registered tcp client for %u->%s:%u (client_id %u pid %u)\n",
			(unsigned)ntohs(tcp_sock->dest.ip.sin_port), 
			ctdb_addr_to_str(&tcp_sock->src),
			(unsigned)ntohs(tcp_sock->src.ip.sin_port), client_id, client->pid));
		break;
	case AF_INET6:
		DEBUG(DEBUG_INFO,("registered tcp client for %u->%s:%u (client_id %u pid %u)\n",
			(unsigned)ntohs(tcp_sock->dest.ip6.sin6_port), 
			ctdb_addr_to_str(&tcp_sock->src),
			(unsigned)ntohs(tcp_sock->src.ip6.sin6_port), client_id, client->pid));
		break;
	default:
		DEBUG(DEBUG_ERR,(__location__ " Unknown family %d\n", addr.sa.sa_family));
	}


	/* tell all nodes about this tcp connection */
	ret = ctdb_daemon_send_control(ctdb, CTDB_BROADCAST_CONNECTED, 0, 
				       CTDB_CONTROL_TCP_ADD,
				       0, CTDB_CTRL_FLAG_NOREPLY, data, NULL, NULL);
	if (ret != 0) {
		DEBUG(DEBUG_ERR,(__location__ " Failed to send CTDB_CONTROL_TCP_ADD\n"));
		return -1;
	}

	return 0;
}

/*
  find a tcp address on a list
 */
static struct ctdb_tcp_connection *ctdb_tcp_find(struct ctdb_tcp_array *array, 
					   struct ctdb_tcp_connection *tcp)
{
	int i;

	if (array == NULL) {
		return NULL;
	}

	for (i=0;i<array->num;i++) {
		if (ctdb_same_sockaddr(&array->connections[i].src_addr, &tcp->src_addr) &&
		    ctdb_same_sockaddr(&array->connections[i].dst_addr, &tcp->dst_addr)) {
			return &array->connections[i];
		}
	}
	return NULL;
}



/*
  called by a daemon to inform us of a TCP connection that one of its
  clients managing that should tickled with an ACK when IP takeover is
  done
 */
int32_t ctdb_control_tcp_add(struct ctdb_context *ctdb, TDB_DATA indata, bool tcp_update_needed)
{
	struct ctdb_tcp_connection *p = (struct ctdb_tcp_connection *)indata.dptr;
	struct ctdb_tcp_array *tcparray;
	struct ctdb_tcp_connection tcp;
	struct ctdb_vnn *vnn;

	vnn = find_public_ip_vnn(ctdb, &p->dst_addr);
	if (vnn == NULL) {
		DEBUG(DEBUG_INFO,(__location__ " got TCP_ADD control for an address which is not a public address '%s'\n",
			ctdb_addr_to_str(&p->dst_addr)));

		return -1;
	}


	tcparray = vnn->tcp_array;

	/* If this is the first tickle */
	if (tcparray == NULL) {
		tcparray = talloc_size(ctdb->nodes, 
			offsetof(struct ctdb_tcp_array, connections) +
			sizeof(struct ctdb_tcp_connection) * 1);
		CTDB_NO_MEMORY(ctdb, tcparray);
		vnn->tcp_array = tcparray;

		tcparray->num = 0;
		tcparray->connections = talloc_size(tcparray, sizeof(struct ctdb_tcp_connection));
		CTDB_NO_MEMORY(ctdb, tcparray->connections);

		tcparray->connections[tcparray->num].src_addr = p->src_addr;
		tcparray->connections[tcparray->num].dst_addr = p->dst_addr;
		tcparray->num++;

		if (tcp_update_needed) {
			vnn->tcp_update_needed = true;
		}
		return 0;
	}


	/* Do we already have this tickle ?*/
	tcp.src_addr = p->src_addr;
	tcp.dst_addr = p->dst_addr;
	if (ctdb_tcp_find(vnn->tcp_array, &tcp) != NULL) {
		DEBUG(DEBUG_DEBUG,("Already had tickle info for %s:%u for vnn:%u\n",
			ctdb_addr_to_str(&tcp.dst_addr),
			ntohs(tcp.dst_addr.ip.sin_port),
			vnn->pnn));
		return 0;
	}

	/* A new tickle, we must add it to the array */
	tcparray->connections = talloc_realloc(tcparray, tcparray->connections,
					struct ctdb_tcp_connection,
					tcparray->num+1);
	CTDB_NO_MEMORY(ctdb, tcparray->connections);

	vnn->tcp_array = tcparray;
	tcparray->connections[tcparray->num].src_addr = p->src_addr;
	tcparray->connections[tcparray->num].dst_addr = p->dst_addr;
	tcparray->num++;
				
	DEBUG(DEBUG_INFO,("Added tickle info for %s:%u from vnn %u\n",
		ctdb_addr_to_str(&tcp.dst_addr),
		ntohs(tcp.dst_addr.ip.sin_port),
		vnn->pnn));

	if (tcp_update_needed) {
		vnn->tcp_update_needed = true;
	}

	return 0;
}


/*
  called by a daemon to inform us of a TCP connection that one of its
  clients managing that should tickled with an ACK when IP takeover is
  done
 */
static void ctdb_remove_tcp_connection(struct ctdb_context *ctdb, struct ctdb_tcp_connection *conn)
{
	struct ctdb_tcp_connection *tcpp;
	struct ctdb_vnn *vnn = find_public_ip_vnn(ctdb, &conn->dst_addr);

	if (vnn == NULL) {
		DEBUG(DEBUG_ERR,(__location__ " unable to find public address %s\n",
			ctdb_addr_to_str(&conn->dst_addr)));
		return;
	}

	/* if the array is empty we cant remove it
	   and we dont need to do anything
	 */
	if (vnn->tcp_array == NULL) {
		DEBUG(DEBUG_INFO,("Trying to remove tickle that doesnt exist (array is empty) %s:%u\n",
			ctdb_addr_to_str(&conn->dst_addr),
			ntohs(conn->dst_addr.ip.sin_port)));
		return;
	}


	/* See if we know this connection
	   if we dont know this connection  then we dont need to do anything
	 */
	tcpp = ctdb_tcp_find(vnn->tcp_array, conn);
	if (tcpp == NULL) {
		DEBUG(DEBUG_INFO,("Trying to remove tickle that doesnt exist %s:%u\n",
			ctdb_addr_to_str(&conn->dst_addr),
			ntohs(conn->dst_addr.ip.sin_port)));
		return;
	}


	/* We need to remove this entry from the array.
           Instead of allocating a new array and copying data to it
	   we cheat and just copy the last entry in the existing array
	   to the entry that is to be removed and just shring the 
	   ->num field
	 */
	*tcpp = vnn->tcp_array->connections[vnn->tcp_array->num - 1];
	vnn->tcp_array->num--;

	/* If we deleted the last entry we also need to remove the entire array
	 */
	if (vnn->tcp_array->num == 0) {
		talloc_free(vnn->tcp_array);
		vnn->tcp_array = NULL;
	}		

	vnn->tcp_update_needed = true;

	DEBUG(DEBUG_INFO,("Removed tickle info for %s:%u\n",
		ctdb_addr_to_str(&conn->src_addr),
		ntohs(conn->src_addr.ip.sin_port)));
}


/*
  called by a daemon to inform us of a TCP connection that one of its
  clients used are no longer needed in the tickle database
 */
int32_t ctdb_control_tcp_remove(struct ctdb_context *ctdb, TDB_DATA indata)
{
	struct ctdb_tcp_connection *conn = (struct ctdb_tcp_connection *)indata.dptr;

	ctdb_remove_tcp_connection(ctdb, conn);

	return 0;
}


/*
  called when a daemon restarts - send all tickes for all public addresses
  we are serving immediately to the new node.
 */
int32_t ctdb_control_startup(struct ctdb_context *ctdb, uint32_t vnn)
{
/*XXX here we should send all tickes we are serving to the new node */
	return 0;
}


/*
  called when a client structure goes away - hook to remove
  elements from the tcp_list in all daemons
 */
void ctdb_takeover_client_destructor_hook(struct ctdb_client *client)
{
	while (client->tcp_list) {
		struct ctdb_tcp_list *tcp = client->tcp_list;
		DLIST_REMOVE(client->tcp_list, tcp);
		ctdb_remove_tcp_connection(client->ctdb, &tcp->connection);
	}
}


/*
  release all IPs on shutdown
 */
void ctdb_release_all_ips(struct ctdb_context *ctdb)
{
	struct ctdb_vnn *vnn;

	for (vnn=ctdb->vnn;vnn;vnn=vnn->next) {
		if (!ctdb_sys_have_ip(&vnn->public_address)) {
			ctdb_vnn_unassign_iface(ctdb, vnn);
			continue;
		}
		if (!vnn->iface) {
			continue;
		}
		ctdb_event_script_args(ctdb, CTDB_EVENT_RELEASE_IP, "%s %s %u",
				  ctdb_vnn_iface_string(vnn),
				  ctdb_addr_to_str(&vnn->public_address),
				  vnn->public_netmask_bits);
		release_kill_clients(ctdb, &vnn->public_address);
		ctdb_vnn_unassign_iface(ctdb, vnn);
	}
}


/*
  get list of public IPs
 */
int32_t ctdb_control_get_public_ips(struct ctdb_context *ctdb, 
				    struct ctdb_req_control *c, TDB_DATA *outdata)
{
	int i, num, len;
	struct ctdb_all_public_ips *ips;
	struct ctdb_vnn *vnn;
	bool only_available = false;

	if (c->flags & CTDB_PUBLIC_IP_FLAGS_ONLY_AVAILABLE) {
		only_available = true;
	}

	/* count how many public ip structures we have */
	num = 0;
	for (vnn=ctdb->vnn;vnn;vnn=vnn->next) {
		num++;
	}

	len = offsetof(struct ctdb_all_public_ips, ips) + 
		num*sizeof(struct ctdb_public_ip);
	ips = talloc_zero_size(outdata, len);
	CTDB_NO_MEMORY(ctdb, ips);

	i = 0;
	for (vnn=ctdb->vnn;vnn;vnn=vnn->next) {
		if (only_available && !ctdb_vnn_available(ctdb, vnn)) {
			continue;
		}
		ips->ips[i].pnn  = vnn->pnn;
		ips->ips[i].addr = vnn->public_address;
		i++;
	}
	ips->num = i;
	len = offsetof(struct ctdb_all_public_ips, ips) +
		i*sizeof(struct ctdb_public_ip);

	outdata->dsize = len;
	outdata->dptr  = (uint8_t *)ips;

	return 0;
}


/*
  get list of public IPs, old ipv4 style.  only returns ipv4 addresses
 */
int32_t ctdb_control_get_public_ipsv4(struct ctdb_context *ctdb, 
				    struct ctdb_req_control *c, TDB_DATA *outdata)
{
	int i, num, len;
	struct ctdb_all_public_ipsv4 *ips;
	struct ctdb_vnn *vnn;

	/* count how many public ip structures we have */
	num = 0;
	for (vnn=ctdb->vnn;vnn;vnn=vnn->next) {
		if (vnn->public_address.sa.sa_family != AF_INET) {
			continue;
		}
		num++;
	}

	len = offsetof(struct ctdb_all_public_ipsv4, ips) + 
		num*sizeof(struct ctdb_public_ipv4);
	ips = talloc_zero_size(outdata, len);
	CTDB_NO_MEMORY(ctdb, ips);

	outdata->dsize = len;
	outdata->dptr  = (uint8_t *)ips;

	ips->num = num;
	i = 0;
	for (vnn=ctdb->vnn;vnn;vnn=vnn->next) {
		if (vnn->public_address.sa.sa_family != AF_INET) {
			continue;
		}
		ips->ips[i].pnn = vnn->pnn;
		ips->ips[i].sin = vnn->public_address.ip;
		i++;
	}

	return 0;
}

int32_t ctdb_control_get_public_ip_info(struct ctdb_context *ctdb,
					struct ctdb_req_control *c,
					TDB_DATA indata,
					TDB_DATA *outdata)
{
	int i, num, len;
	ctdb_sock_addr *addr;
	struct ctdb_control_public_ip_info *info;
	struct ctdb_vnn *vnn;

	addr = (ctdb_sock_addr *)indata.dptr;

	vnn = find_public_ip_vnn(ctdb, addr);
	if (vnn == NULL) {
		/* if it is not a public ip   it could be our 'single ip' */
		if (ctdb->single_ip_vnn) {
			if (ctdb_same_ip(&ctdb->single_ip_vnn->public_address, addr)) {
				vnn = ctdb->single_ip_vnn;
			}
		}
	}
	if (vnn == NULL) {
		DEBUG(DEBUG_ERR,(__location__ " Could not get public ip info, "
				 "'%s'not a public address\n",
				 ctdb_addr_to_str(addr)));
		return -1;
	}

	/* count how many public ip structures we have */
	num = 0;
	for (;vnn->ifaces[num];) {
		num++;
	}

	len = offsetof(struct ctdb_control_public_ip_info, ifaces) +
		num*sizeof(struct ctdb_control_iface_info);
	info = talloc_zero_size(outdata, len);
	CTDB_NO_MEMORY(ctdb, info);

	info->ip.addr = vnn->public_address;
	info->ip.pnn = vnn->pnn;
	info->active_idx = 0xFFFFFFFF;

	for (i=0; vnn->ifaces[i]; i++) {
		struct ctdb_iface *cur;

		cur = ctdb_find_iface(ctdb, vnn->ifaces[i]);
		if (cur == NULL) {
			DEBUG(DEBUG_CRIT, (__location__ " internal error iface[%s] unknown\n",
					   vnn->ifaces[i]));
			return -1;
		}
		if (vnn->iface == cur) {
			info->active_idx = i;
		}
		strcpy(info->ifaces[i].name, cur->name);
		info->ifaces[i].link_state = cur->link_up;
		info->ifaces[i].references = cur->references;
	}
	info->num = i;
	len = offsetof(struct ctdb_control_public_ip_info, ifaces) +
		i*sizeof(struct ctdb_control_iface_info);

	outdata->dsize = len;
	outdata->dptr  = (uint8_t *)info;

	return 0;
}

int32_t ctdb_control_get_ifaces(struct ctdb_context *ctdb,
				struct ctdb_req_control *c,
				TDB_DATA *outdata)
{
	int i, num, len;
	struct ctdb_control_get_ifaces *ifaces;
	struct ctdb_iface *cur;

	/* count how many public ip structures we have */
	num = 0;
	for (cur=ctdb->ifaces;cur;cur=cur->next) {
		num++;
	}

	len = offsetof(struct ctdb_control_get_ifaces, ifaces) +
		num*sizeof(struct ctdb_control_iface_info);
	ifaces = talloc_zero_size(outdata, len);
	CTDB_NO_MEMORY(ctdb, ifaces);

	i = 0;
	for (cur=ctdb->ifaces;cur;cur=cur->next) {
		strcpy(ifaces->ifaces[i].name, cur->name);
		ifaces->ifaces[i].link_state = cur->link_up;
		ifaces->ifaces[i].references = cur->references;
		i++;
	}
	ifaces->num = i;
	len = offsetof(struct ctdb_control_get_ifaces, ifaces) +
		i*sizeof(struct ctdb_control_iface_info);

	outdata->dsize = len;
	outdata->dptr  = (uint8_t *)ifaces;

	return 0;
}

int32_t ctdb_control_set_iface_link(struct ctdb_context *ctdb,
				    struct ctdb_req_control *c,
				    TDB_DATA indata)
{
	struct ctdb_control_iface_info *info;
	struct ctdb_iface *iface;
	bool link_up = false;

	info = (struct ctdb_control_iface_info *)indata.dptr;

	if (info->name[CTDB_IFACE_SIZE] != '\0') {
		int len = strnlen(info->name, CTDB_IFACE_SIZE);
		DEBUG(DEBUG_ERR, (__location__ " name[%*.*s] not terminated\n",
				  len, len, info->name));
		return -1;
	}

	switch (info->link_state) {
	case 0:
		link_up = false;
		break;
	case 1:
		link_up = true;
		break;
	default:
		DEBUG(DEBUG_ERR, (__location__ " link_state[%u] invalid\n",
				  (unsigned int)info->link_state));
		return -1;
	}

	if (info->references != 0) {
		DEBUG(DEBUG_ERR, (__location__ " references[%u] should be 0\n",
				  (unsigned int)info->references));
		return -1;
	}

	iface = ctdb_find_iface(ctdb, info->name);
	if (iface == NULL) {
		return -1;
	}

	if (link_up == iface->link_up) {
		return 0;
	}

	DEBUG(iface->link_up?DEBUG_ERR:DEBUG_NOTICE,
	      ("iface[%s] has changed it's link status %s => %s\n",
	       iface->name,
	       iface->link_up?"up":"down",
	       link_up?"up":"down"));

	iface->link_up = link_up;
	return 0;
}


/* 
   structure containing the listening socket and the list of tcp connections
   that the ctdb daemon is to kill
*/
struct ctdb_kill_tcp {
	struct ctdb_vnn *vnn;
	struct ctdb_context *ctdb;
	int capture_fd;
	struct fd_event *fde;
	trbt_tree_t *connections;
	void *private_data;
};

/*
  a tcp connection that is to be killed
 */
struct ctdb_killtcp_con {
	ctdb_sock_addr src_addr;
	ctdb_sock_addr dst_addr;
	int count;
	struct ctdb_kill_tcp *killtcp;
};

/* this function is used to create a key to represent this socketpair
   in the killtcp tree.
   this key is used to insert and lookup matching socketpairs that are
   to be tickled and RST
*/
#define KILLTCP_KEYLEN	10
static uint32_t *killtcp_key(ctdb_sock_addr *src, ctdb_sock_addr *dst)
{
	static uint32_t key[KILLTCP_KEYLEN];

	bzero(key, sizeof(key));

	if (src->sa.sa_family != dst->sa.sa_family) {
		DEBUG(DEBUG_ERR, (__location__ " ERROR, different families passed :%u vs %u\n", src->sa.sa_family, dst->sa.sa_family));
		return key;
	}
	
	switch (src->sa.sa_family) {
	case AF_INET:
		key[0]	= dst->ip.sin_addr.s_addr;
		key[1]	= src->ip.sin_addr.s_addr;
		key[2]	= dst->ip.sin_port;
		key[3]	= src->ip.sin_port;
		break;
	case AF_INET6: {
		uint32_t *dst6_addr32 =
			(uint32_t *)&(dst->ip6.sin6_addr.s6_addr);
		uint32_t *src6_addr32 =
			(uint32_t *)&(src->ip6.sin6_addr.s6_addr);
		key[0]	= dst6_addr32[3];
		key[1]	= src6_addr32[3];
		key[2]	= dst6_addr32[2];
		key[3]	= src6_addr32[2];
		key[4]	= dst6_addr32[1];
		key[5]	= src6_addr32[1];
		key[6]	= dst6_addr32[0];
		key[7]	= src6_addr32[0];
		key[8]	= dst->ip6.sin6_port;
		key[9]	= src->ip6.sin6_port;
		break;
	}
	default:
		DEBUG(DEBUG_ERR, (__location__ " ERROR, unknown family passed :%u\n", src->sa.sa_family));
		return key;
	}

	return key;
}

/*
  called when we get a read event on the raw socket
 */
static void capture_tcp_handler(struct event_context *ev, struct fd_event *fde, 
				uint16_t flags, void *private_data)
{
	struct ctdb_kill_tcp *killtcp = talloc_get_type(private_data, struct ctdb_kill_tcp);
	struct ctdb_killtcp_con *con;
	ctdb_sock_addr src, dst;
	uint32_t ack_seq, seq;

	if (!(flags & EVENT_FD_READ)) {
		return;
	}

	if (ctdb_sys_read_tcp_packet(killtcp->capture_fd,
				killtcp->private_data,
				&src, &dst,
				&ack_seq, &seq) != 0) {
		/* probably a non-tcp ACK packet */
		return;
	}

	/* check if we have this guy in our list of connections
	   to kill
	*/
	con = trbt_lookuparray32(killtcp->connections, 
			KILLTCP_KEYLEN, killtcp_key(&src, &dst));
	if (con == NULL) {
		/* no this was some other packet we can just ignore */
		return;
	}

	/* This one has been tickled !
	   now reset him and remove him from the list.
	 */
	DEBUG(DEBUG_INFO, ("sending a tcp reset to kill connection :%d -> %s:%d\n",
		ntohs(con->dst_addr.ip.sin_port),
		ctdb_addr_to_str(&con->src_addr),
		ntohs(con->src_addr.ip.sin_port)));

	ctdb_sys_send_tcp(&con->dst_addr, &con->src_addr, ack_seq, seq, 1);
	talloc_free(con);
}


/* when traversing the list of all tcp connections to send tickle acks to
   (so that we can capture the ack coming back and kill the connection
    by a RST)
   this callback is called for each connection we are currently trying to kill
*/
static int tickle_connection_traverse(void *param, void *data)
{
	struct ctdb_killtcp_con *con = talloc_get_type(data, struct ctdb_killtcp_con);

	/* have tried too many times, just give up */
	if (con->count >= 5) {
		/* can't delete in traverse: reparent to delete_cons */
		talloc_steal(param, con);
		return 0;
	}

	/* othervise, try tickling it again */
	con->count++;
	ctdb_sys_send_tcp(
		(ctdb_sock_addr *)&con->dst_addr,
		(ctdb_sock_addr *)&con->src_addr,
		0, 0, 0);
	return 0;
}


/* 
   called every second until all sentenced connections have been reset
 */
static void ctdb_tickle_sentenced_connections(struct event_context *ev, struct timed_event *te, 
					      struct timeval t, void *private_data)
{
	struct ctdb_kill_tcp *killtcp = talloc_get_type(private_data, struct ctdb_kill_tcp);
	void *delete_cons = talloc_new(NULL);

	/* loop over all connections sending tickle ACKs */
	trbt_traversearray32(killtcp->connections, KILLTCP_KEYLEN, tickle_connection_traverse, delete_cons);

	/* now we've finished traverse, it's safe to do deletion. */
	talloc_free(delete_cons);

	/* If there are no more connections to kill we can remove the
	   entire killtcp structure
	 */
	if ( (killtcp->connections == NULL) || 
	     (killtcp->connections->root == NULL) ) {
		talloc_free(killtcp);
		return;
	}

	/* try tickling them again in a seconds time
	 */
	event_add_timed(killtcp->ctdb->ev, killtcp, timeval_current_ofs(1, 0), 
			ctdb_tickle_sentenced_connections, killtcp);
}

/*
  destroy the killtcp structure
 */
static int ctdb_killtcp_destructor(struct ctdb_kill_tcp *killtcp)
{
	struct ctdb_vnn *tmpvnn;

	/* verify that this vnn is still active */
	for (tmpvnn = killtcp->ctdb->vnn; tmpvnn; tmpvnn = tmpvnn->next) {
		if (tmpvnn == killtcp->vnn) {
			break;
		}
	}

	if (tmpvnn == NULL) {
		return 0;
	}

	if (killtcp->vnn->killtcp != killtcp) {
		return 0;
	}

	killtcp->vnn->killtcp = NULL;

	return 0;
}


/* nothing fancy here, just unconditionally replace any existing
   connection structure with the new one.

   dont even free the old one if it did exist, that one is talloc_stolen
   by the same node in the tree anyway and will be deleted when the new data 
   is deleted
*/
static void *add_killtcp_callback(void *parm, void *data)
{
	return parm;
}

/*
  add a tcp socket to the list of connections we want to RST
 */
static int ctdb_killtcp_add_connection(struct ctdb_context *ctdb, 
				       ctdb_sock_addr *s,
				       ctdb_sock_addr *d)
{
	ctdb_sock_addr src, dst;
	struct ctdb_kill_tcp *killtcp;
	struct ctdb_killtcp_con *con;
	struct ctdb_vnn *vnn;

	ctdb_canonicalize_ip(s, &src);
	ctdb_canonicalize_ip(d, &dst);

	vnn = find_public_ip_vnn(ctdb, &dst);
	if (vnn == NULL) {
		vnn = find_public_ip_vnn(ctdb, &src);
	}
	if (vnn == NULL) {
		/* if it is not a public ip   it could be our 'single ip' */
		if (ctdb->single_ip_vnn) {
			if (ctdb_same_ip(&ctdb->single_ip_vnn->public_address, &dst)) {
				vnn = ctdb->single_ip_vnn;
			}
		}
	}
	if (vnn == NULL) {
		DEBUG(DEBUG_ERR,(__location__ " Could not killtcp, not a public address\n")); 
		return -1;
	}

	killtcp = vnn->killtcp;
	
	/* If this is the first connection to kill we must allocate
	   a new structure
	 */
	if (killtcp == NULL) {
		killtcp = talloc_zero(vnn, struct ctdb_kill_tcp);
		CTDB_NO_MEMORY(ctdb, killtcp);

		killtcp->vnn         = vnn;
		killtcp->ctdb        = ctdb;
		killtcp->capture_fd  = -1;
		killtcp->connections = trbt_create(killtcp, 0);

		vnn->killtcp         = killtcp;
		talloc_set_destructor(killtcp, ctdb_killtcp_destructor);
	}



	/* create a structure that describes this connection we want to
	   RST and store it in killtcp->connections
	*/
	con = talloc(killtcp, struct ctdb_killtcp_con);
	CTDB_NO_MEMORY(ctdb, con);
	con->src_addr = src;
	con->dst_addr = dst;
	con->count    = 0;
	con->killtcp  = killtcp;


	trbt_insertarray32_callback(killtcp->connections,
			KILLTCP_KEYLEN, killtcp_key(&con->dst_addr, &con->src_addr),
			add_killtcp_callback, con);

	/* 
	   If we dont have a socket to listen on yet we must create it
	 */
	if (killtcp->capture_fd == -1) {
		const char *iface = ctdb_vnn_iface_string(vnn);
		killtcp->capture_fd = ctdb_sys_open_capture_socket(iface, &killtcp->private_data);
		if (killtcp->capture_fd == -1) {
			DEBUG(DEBUG_CRIT,(__location__ " Failed to open capturing "
					  "socket on iface '%s' for killtcp (%s)\n",
					  iface, strerror(errno)));
			goto failed;
		}
	}


	if (killtcp->fde == NULL) {
		killtcp->fde = event_add_fd(ctdb->ev, killtcp, killtcp->capture_fd, 
					    EVENT_FD_READ,
					    capture_tcp_handler, killtcp);
		tevent_fd_set_auto_close(killtcp->fde);

		/* We also need to set up some events to tickle all these connections
		   until they are all reset
		*/
		event_add_timed(ctdb->ev, killtcp, timeval_current_ofs(1, 0), 
				ctdb_tickle_sentenced_connections, killtcp);
	}

	/* tickle him once now */
	ctdb_sys_send_tcp(
		&con->dst_addr,
		&con->src_addr,
		0, 0, 0);

	return 0;

failed:
	talloc_free(vnn->killtcp);
	vnn->killtcp = NULL;
	return -1;
}

/*
  kill a TCP connection.
 */
int32_t ctdb_control_kill_tcp(struct ctdb_context *ctdb, TDB_DATA indata)
{
	struct ctdb_control_killtcp *killtcp = (struct ctdb_control_killtcp *)indata.dptr;

	return ctdb_killtcp_add_connection(ctdb, &killtcp->src_addr, &killtcp->dst_addr);
}

/*
  called by a daemon to inform us of the entire list of TCP tickles for
  a particular public address.
  this control should only be sent by the node that is currently serving
  that public address.
 */
int32_t ctdb_control_set_tcp_tickle_list(struct ctdb_context *ctdb, TDB_DATA indata)
{
	struct ctdb_control_tcp_tickle_list *list = (struct ctdb_control_tcp_tickle_list *)indata.dptr;
	struct ctdb_tcp_array *tcparray;
	struct ctdb_vnn *vnn;

	/* We must at least have tickles.num or else we cant verify the size
	   of the received data blob
	 */
	if (indata.dsize < offsetof(struct ctdb_control_tcp_tickle_list, 
					tickles.connections)) {
		DEBUG(DEBUG_ERR,("Bad indata in ctdb_control_set_tcp_tickle_list. Not enough data for the tickle.num field\n"));
		return -1;
	}

	/* verify that the size of data matches what we expect */
	if (indata.dsize < offsetof(struct ctdb_control_tcp_tickle_list, 
				tickles.connections)
			 + sizeof(struct ctdb_tcp_connection)
				 * list->tickles.num) {
		DEBUG(DEBUG_ERR,("Bad indata in ctdb_control_set_tcp_tickle_list\n"));
		return -1;
	}	

	vnn = find_public_ip_vnn(ctdb, &list->addr);
	if (vnn == NULL) {
		DEBUG(DEBUG_INFO,(__location__ " Could not set tcp tickle list, '%s' is not a public address\n", 
			ctdb_addr_to_str(&list->addr)));

		return 1;
	}

	/* remove any old ticklelist we might have */
	talloc_free(vnn->tcp_array);
	vnn->tcp_array = NULL;

	tcparray = talloc(ctdb->nodes, struct ctdb_tcp_array);
	CTDB_NO_MEMORY(ctdb, tcparray);

	tcparray->num = list->tickles.num;

	tcparray->connections = talloc_array(tcparray, struct ctdb_tcp_connection, tcparray->num);
	CTDB_NO_MEMORY(ctdb, tcparray->connections);

	memcpy(tcparray->connections, &list->tickles.connections[0], 
	       sizeof(struct ctdb_tcp_connection)*tcparray->num);

	/* We now have a new fresh tickle list array for this vnn */
	vnn->tcp_array = talloc_steal(vnn, tcparray);
	
	return 0;
}

/*
  called to return the full list of tickles for the puclic address associated 
  with the provided vnn
 */
int32_t ctdb_control_get_tcp_tickle_list(struct ctdb_context *ctdb, TDB_DATA indata, TDB_DATA *outdata)
{
	ctdb_sock_addr *addr = (ctdb_sock_addr *)indata.dptr;
	struct ctdb_control_tcp_tickle_list *list;
	struct ctdb_tcp_array *tcparray;
	int num;
	struct ctdb_vnn *vnn;

	vnn = find_public_ip_vnn(ctdb, addr);
	if (vnn == NULL) {
		DEBUG(DEBUG_ERR,(__location__ " Could not get tcp tickle list, '%s' is not a public address\n", 
			ctdb_addr_to_str(addr)));

		return 1;
	}

	tcparray = vnn->tcp_array;
	if (tcparray) {
		num = tcparray->num;
	} else {
		num = 0;
	}

	outdata->dsize = offsetof(struct ctdb_control_tcp_tickle_list, 
				tickles.connections)
			+ sizeof(struct ctdb_tcp_connection) * num;

	outdata->dptr  = talloc_size(outdata, outdata->dsize);
	CTDB_NO_MEMORY(ctdb, outdata->dptr);
	list = (struct ctdb_control_tcp_tickle_list *)outdata->dptr;

	list->addr = *addr;
	list->tickles.num = num;
	if (num) {
		memcpy(&list->tickles.connections[0], tcparray->connections, 
			sizeof(struct ctdb_tcp_connection) * num);
	}

	return 0;
}


/*
  set the list of all tcp tickles for a public address
 */
static int ctdb_ctrl_set_tcp_tickles(struct ctdb_context *ctdb, 
			      struct timeval timeout, uint32_t destnode, 
			      ctdb_sock_addr *addr,
			      struct ctdb_tcp_array *tcparray)
{
	int ret, num;
	TDB_DATA data;
	struct ctdb_control_tcp_tickle_list *list;

	if (tcparray) {
		num = tcparray->num;
	} else {
		num = 0;
	}

	data.dsize = offsetof(struct ctdb_control_tcp_tickle_list, 
				tickles.connections) +
			sizeof(struct ctdb_tcp_connection) * num;
	data.dptr = talloc_size(ctdb, data.dsize);
	CTDB_NO_MEMORY(ctdb, data.dptr);

	list = (struct ctdb_control_tcp_tickle_list *)data.dptr;
	list->addr = *addr;
	list->tickles.num = num;
	if (tcparray) {
		memcpy(&list->tickles.connections[0], tcparray->connections, sizeof(struct ctdb_tcp_connection) * num);
	}

	ret = ctdb_daemon_send_control(ctdb, CTDB_BROADCAST_CONNECTED, 0, 
				       CTDB_CONTROL_SET_TCP_TICKLE_LIST,
				       0, CTDB_CTRL_FLAG_NOREPLY, data, NULL, NULL);
	if (ret != 0) {
		DEBUG(DEBUG_ERR,(__location__ " ctdb_control for set tcp tickles failed\n"));
		return -1;
	}

	talloc_free(data.dptr);

	return ret;
}


/*
  perform tickle updates if required
 */
static void ctdb_update_tcp_tickles(struct event_context *ev, 
				struct timed_event *te, 
				struct timeval t, void *private_data)
{
	struct ctdb_context *ctdb = talloc_get_type(private_data, struct ctdb_context);
	int ret;
	struct ctdb_vnn *vnn;

	for (vnn=ctdb->vnn;vnn;vnn=vnn->next) {
		/* we only send out updates for public addresses that 
		   we have taken over
		 */
		if (ctdb->pnn != vnn->pnn) {
			continue;
		}
		/* We only send out the updates if we need to */
		if (!vnn->tcp_update_needed) {
			continue;
		}
		ret = ctdb_ctrl_set_tcp_tickles(ctdb, 
				TAKEOVER_TIMEOUT(),
				CTDB_BROADCAST_CONNECTED,
				&vnn->public_address,
				vnn->tcp_array);
		if (ret != 0) {
			DEBUG(DEBUG_ERR,("Failed to send the tickle update for public address %s\n",
				ctdb_addr_to_str(&vnn->public_address)));
		}
	}

	event_add_timed(ctdb->ev, ctdb->tickle_update_context,
			     timeval_current_ofs(ctdb->tunable.tickle_update_interval, 0), 
			     ctdb_update_tcp_tickles, ctdb);
}		
	

/*
  start periodic update of tcp tickles
 */
void ctdb_start_tcp_tickle_update(struct ctdb_context *ctdb)
{
	ctdb->tickle_update_context = talloc_new(ctdb);

	event_add_timed(ctdb->ev, ctdb->tickle_update_context,
			     timeval_current_ofs(ctdb->tunable.tickle_update_interval, 0), 
			     ctdb_update_tcp_tickles, ctdb);
}




struct control_gratious_arp {
	struct ctdb_context *ctdb;
	ctdb_sock_addr addr;
	const char *iface;
	int count;
};

/*
  send a control_gratuitous arp
 */
static void send_gratious_arp(struct event_context *ev, struct timed_event *te, 
				  struct timeval t, void *private_data)
{
	int ret;
	struct control_gratious_arp *arp = talloc_get_type(private_data, 
							struct control_gratious_arp);

	ret = ctdb_sys_send_arp(&arp->addr, arp->iface);
	if (ret != 0) {
		DEBUG(DEBUG_ERR,(__location__ " sending of gratious arp on iface '%s' failed (%s)\n",
				 arp->iface, strerror(errno)));
	}


	arp->count++;
	if (arp->count == CTDB_ARP_REPEAT) {
		talloc_free(arp);
		return;
	}

	event_add_timed(arp->ctdb->ev, arp, 
			timeval_current_ofs(CTDB_ARP_INTERVAL, 0), 
			send_gratious_arp, arp);
}


/*
  send a gratious arp 
 */
int32_t ctdb_control_send_gratious_arp(struct ctdb_context *ctdb, TDB_DATA indata)
{
	struct ctdb_control_gratious_arp *gratious_arp = (struct ctdb_control_gratious_arp *)indata.dptr;
	struct control_gratious_arp *arp;

	/* verify the size of indata */
	if (indata.dsize < offsetof(struct ctdb_control_gratious_arp, iface)) {
		DEBUG(DEBUG_ERR,(__location__ " Too small indata to hold a ctdb_control_gratious_arp structure. Got %u require %u bytes\n", 
				 (unsigned)indata.dsize, 
				 (unsigned)offsetof(struct ctdb_control_gratious_arp, iface)));
		return -1;
	}
	if (indata.dsize != 
		( offsetof(struct ctdb_control_gratious_arp, iface)
		+ gratious_arp->len ) ){

		DEBUG(DEBUG_ERR,(__location__ " Wrong size of indata. Was %u bytes "
			"but should be %u bytes\n", 
			 (unsigned)indata.dsize, 
			 (unsigned)(offsetof(struct ctdb_control_gratious_arp, iface)+gratious_arp->len)));
		return -1;
	}


	arp = talloc(ctdb, struct control_gratious_arp);
	CTDB_NO_MEMORY(ctdb, arp);

	arp->ctdb  = ctdb;
	arp->addr   = gratious_arp->addr;
	arp->iface = talloc_strdup(arp, gratious_arp->iface);
	CTDB_NO_MEMORY(ctdb, arp->iface);
	arp->count = 0;
	
	event_add_timed(arp->ctdb->ev, arp, 
			timeval_zero(), send_gratious_arp, arp);

	return 0;
}

int32_t ctdb_control_add_public_address(struct ctdb_context *ctdb, TDB_DATA indata)
{
	struct ctdb_control_ip_iface *pub = (struct ctdb_control_ip_iface *)indata.dptr;
	int ret;

	/* verify the size of indata */
	if (indata.dsize < offsetof(struct ctdb_control_ip_iface, iface)) {
		DEBUG(DEBUG_ERR,(__location__ " Too small indata to hold a ctdb_control_ip_iface structure\n"));
		return -1;
	}
	if (indata.dsize != 
		( offsetof(struct ctdb_control_ip_iface, iface)
		+ pub->len ) ){

		DEBUG(DEBUG_ERR,(__location__ " Wrong size of indata. Was %u bytes "
			"but should be %u bytes\n", 
			 (unsigned)indata.dsize, 
			 (unsigned)(offsetof(struct ctdb_control_ip_iface, iface)+pub->len)));
		return -1;
	}

	ret = ctdb_add_public_address(ctdb, &pub->addr, pub->mask, &pub->iface[0]);

	if (ret != 0) {
		DEBUG(DEBUG_ERR,(__location__ " Failed to add public address\n"));
		return -1;
	}

	return 0;
}

/*
  called when releaseip event finishes for del_public_address
 */
static void delete_ip_callback(struct ctdb_context *ctdb, int status, 
				void *private_data)
{
	talloc_free(private_data);
}

int32_t ctdb_control_del_public_address(struct ctdb_context *ctdb, TDB_DATA indata)
{
	struct ctdb_control_ip_iface *pub = (struct ctdb_control_ip_iface *)indata.dptr;
	struct ctdb_vnn *vnn;
	int ret;

	/* verify the size of indata */
	if (indata.dsize < offsetof(struct ctdb_control_ip_iface, iface)) {
		DEBUG(DEBUG_ERR,(__location__ " Too small indata to hold a ctdb_control_ip_iface structure\n"));
		return -1;
	}
	if (indata.dsize != 
		( offsetof(struct ctdb_control_ip_iface, iface)
		+ pub->len ) ){

		DEBUG(DEBUG_ERR,(__location__ " Wrong size of indata. Was %u bytes "
			"but should be %u bytes\n", 
			 (unsigned)indata.dsize, 
			 (unsigned)(offsetof(struct ctdb_control_ip_iface, iface)+pub->len)));
		return -1;
	}

	/* walk over all public addresses until we find a match */
	for (vnn=ctdb->vnn;vnn;vnn=vnn->next) {
		if (ctdb_same_ip(&vnn->public_address, &pub->addr)) {
			TALLOC_CTX *mem_ctx;

			DLIST_REMOVE(ctdb->vnn, vnn);
			if (vnn->pnn != ctdb->pnn) {
				if (vnn->iface != NULL) {
					ctdb_vnn_unassign_iface(ctdb, vnn);
				}
				talloc_free(vnn);
				return 0;
			}
			vnn->pnn = -1;

			mem_ctx = talloc_new(ctdb);
			talloc_steal(mem_ctx, vnn);
			ret = ctdb_event_script_callback(ctdb, 
					 mem_ctx, delete_ip_callback, mem_ctx,
					 false,
					 CTDB_EVENT_RELEASE_IP,
					 "%s %s %u",
					 ctdb_vnn_iface_string(vnn),
					 ctdb_addr_to_str(&vnn->public_address),
					 vnn->public_netmask_bits);
			if (vnn->iface != NULL) {
				ctdb_vnn_unassign_iface(ctdb, vnn);
			}
			if (ret != 0) {
				return -1;
			}
			return 0;
		}
	}

	return -1;
}

/* This function is called from the recovery daemon to verify that a remote
   node has the expected ip allocation.
   This is verified against ctdb->ip_tree
*/
int verify_remote_ip_allocation(struct ctdb_context *ctdb, struct ctdb_all_public_ips *ips)
{
	struct ctdb_public_ip_list *tmp_ip; 
	int i;

	if (ctdb->ip_tree == NULL) {
		/* dont know the expected allocation yet, assume remote node
		   is correct. */
		return 0;
	}

	if (ips == NULL) {
		return 0;
	}

	for (i=0; i<ips->num; i++) {
		tmp_ip = trbt_lookuparray32(ctdb->ip_tree, IP_KEYLEN, ip_key(&ips->ips[i].addr));
		if (tmp_ip == NULL) {
			DEBUG(DEBUG_ERR,(__location__ " Could not find host for address %s, reassign ips\n", ctdb_addr_to_str(&ips->ips[i].addr)));
			return -1;
		}

		if (tmp_ip->pnn == -1 || ips->ips[i].pnn == -1) {
			continue;
		}

		if (tmp_ip->pnn != ips->ips[i].pnn) {
			DEBUG(DEBUG_ERR,("Inconsistent ip allocation. Trigger reallocation. Thinks %s is held by node %u while it is held by node %u\n", ctdb_addr_to_str(&ips->ips[i].addr), ips->ips[i].pnn, tmp_ip->pnn));
			return -1;
		}
	}

	return 0;
}

int update_ip_assignment_tree(struct ctdb_context *ctdb, struct ctdb_public_ip *ip)
{
	struct ctdb_public_ip_list *tmp_ip; 

	if (ctdb->ip_tree == NULL) {
		DEBUG(DEBUG_ERR,("No ctdb->ip_tree yet. Failed to update ip assignment\n"));
		return -1;
	}

	tmp_ip = trbt_lookuparray32(ctdb->ip_tree, IP_KEYLEN, ip_key(&ip->addr));
	if (tmp_ip == NULL) {
		DEBUG(DEBUG_ERR,(__location__ " Could not find record for address %s, update ip\n", ctdb_addr_to_str(&ip->addr)));
		return -1;
	}

	DEBUG(DEBUG_NOTICE,("Updated ip assignment tree for ip : %s from node %u to node %u\n", ctdb_addr_to_str(&ip->addr), tmp_ip->pnn, ip->pnn));
	tmp_ip->pnn = ip->pnn;

	return 0;
}