ctdb_takeover.c

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/* 
   ctdb recovery code

   Copyright (C) Ronnie Sahlberg  2007
   Copyright (C) Andrew Tridgell  2007

   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/events/events.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"


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

#define CTDB_ARP_INTERVAL 1
#define CTDB_ARP_REPEAT   3

struct ctdb_takeover_arp {
	struct ctdb_context *ctdb;
	uint32_t count;
	struct sockaddr_in sin;
	struct ctdb_tcp_list *tcp_list;
};

/*
  lists of tcp endpoints
 */
struct ctdb_tcp_list {
	struct ctdb_tcp_list *prev, *next;
	uint32_t vnn;
	struct sockaddr_in saddr;
	struct sockaddr_in daddr;
};


/*
  list of clients to kill on IP release
 */
struct ctdb_client_ip {
	struct ctdb_client_ip *prev, *next;
	struct ctdb_context *ctdb;
	struct sockaddr_in ip;
	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 ret;
	struct ctdb_tcp_list *tcp;

	ret = ctdb_sys_send_arp(&arp->sin, arp->ctdb->takeover.interface);
	if (ret != 0) {
		DEBUG(0,(__location__ " sending of arp failed (%s)\n", strerror(errno)));
	}

	for (tcp=arp->tcp_list;tcp;tcp=tcp->next) {
		DEBUG(2,("sending tcp tickle ack for %u->%s:%u\n",
			 (unsigned)ntohs(tcp->daddr.sin_port), 
			 inet_ntoa(tcp->saddr.sin_addr),
			 (unsigned)ntohs(tcp->saddr.sin_port)));
		ret = ctdb_sys_send_tcp(&tcp->saddr, &tcp->daddr, 0, 0, 0);
		if (ret != 0) {
			DEBUG(0,(__location__ " Failed to send tcp tickle ack for %s\n",
				 inet_ntoa(tcp->saddr.sin_addr)));
		}
	}

	arp->count++;

	if (arp->count == CTDB_ARP_REPEAT) {
		talloc_free(arp);
		return;
	}
	
	event_add_timed(arp->ctdb->ev, arp->ctdb->takeover.last_ctx, 
			timeval_current_ofs(CTDB_ARP_INTERVAL, 0), 
			ctdb_control_send_arp, arp);
}

struct takeover_callback_state {
	struct ctdb_req_control *c;
	struct sockaddr_in *sin;
};

/*
  called when takeip event finishes
 */
static void takeover_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);
	struct ctdb_takeover_arp *arp;
	char *ip = inet_ntoa(state->sin->sin_addr);
	struct ctdb_tcp_list *tcp;

	ctdb_start_monitoring(ctdb);

	if (status != 0) {
		DEBUG(0,(__location__ " Failed to takeover IP %s on interface %s\n",
			 ip, ctdb->takeover.interface));
		ctdb_request_control_reply(ctdb, state->c, NULL, status, NULL);
		talloc_free(state);
		return;
	}

	if (!ctdb->takeover.last_ctx) {
		ctdb->takeover.last_ctx = talloc_new(ctdb);
		if (!ctdb->takeover.last_ctx) goto failed;
	}

	arp = talloc_zero(ctdb->takeover.last_ctx, struct ctdb_takeover_arp);
	if (!arp) goto failed;
	
	arp->ctdb = ctdb;
	arp->sin = *state->sin;

	/* add all of the known tcp connections for this IP to the
	   list of tcp connections to send tickle acks for */
	for (tcp=ctdb->tcp_list;tcp;tcp=tcp->next) {
		if (state->sin->sin_addr.s_addr == tcp->daddr.sin_addr.s_addr) {
			struct ctdb_tcp_list *t2 = talloc(arp, struct ctdb_tcp_list);
			if (t2 == NULL) goto failed;
			*t2 = *tcp;
			DLIST_ADD(arp->tcp_list, t2);
		}
	}

	event_add_timed(arp->ctdb->ev, arp->ctdb->takeover.last_ctx, 
			timeval_zero(), ctdb_control_send_arp, arp);

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

failed:
	ctdb_request_control_reply(ctdb, state->c, NULL, -1, NULL);
	talloc_free(state);
	return;
}

/*
  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 takeover_callback_state *state;
	struct ctdb_public_ip *pip = (struct ctdb_public_ip *)indata.dptr;
	char *ip = inet_ntoa(pip->sin.sin_addr);


	/* update out node table */
	ctdb->nodes[pip->vnn]->takeover_vnn = pip->takeover_vnn;

	/* if our kernel already has this IP, do nothing */
	if (ctdb_sys_have_ip(ip)) {
		return 0;
	}

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

	state->c = talloc_steal(ctdb, c);
	state->sin = talloc(ctdb, struct sockaddr_in);       
	CTDB_NO_MEMORY(ctdb, state->sin);
	*state->sin = pip->sin;

	DEBUG(0,("Takover of IP %s/%u on interface %s\n", 
		 ip, ctdb->nodes[ctdb->vnn]->public_netmask_bits, 
		 ctdb->takeover.interface));

	ctdb_stop_monitoring(ctdb);

	ret = ctdb_event_script_callback(ctdb, 
					 timeval_current_ofs(ctdb->tunable.script_timeout, 0),
					 state, takeover_ip_callback, state,
					 "takeip %s %s %u",
					 ctdb->takeover.interface, 
					 ip,
					 ctdb->nodes[ctdb->vnn]->public_netmask_bits);
	if (ret != 0) {
		DEBUG(0,(__location__ " Failed to takeover IP %s on interface %s\n",
			 ip, ctdb->takeover.interface));
		talloc_free(state);
		return -1;
	}

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

	return 0;
}

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

	for (ip=ctdb->client_ip_list; ip; ip=ip->next) {
		if (ip->ip.sin_addr.s_addr == in.s_addr) {
			struct ctdb_client *client = ctdb_reqid_find(ctdb, 
								     ip->client_id, 
								     struct ctdb_client);
			if (client->pid != 0) {
				DEBUG(0,(__location__ " Killing client pid %u for IP %s on client_id %u\n",
					 (unsigned)client->pid, inet_ntoa(in),
					 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);
	char *ip = inet_ntoa(state->sin->sin_addr);
	TDB_DATA data;
	struct ctdb_tcp_list *tcp;

	ctdb_start_monitoring(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 *)ip;
	data.dsize = strlen(ip)+1;

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

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

	/* tell other nodes about any tcp connections we were holding with this IP */
	for (tcp=ctdb->tcp_list;tcp;tcp=tcp->next) {
		if (tcp->vnn == ctdb->vnn && 
		    state->sin->sin_addr.s_addr == tcp->daddr.sin_addr.s_addr) {
			struct ctdb_control_tcp_vnn t;

			t.vnn  = ctdb->vnn;
			t.src  = tcp->saddr;
			t.dest = tcp->daddr;

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

			ctdb_daemon_send_control(ctdb, CTDB_BROADCAST_CONNECTED, 0, 
						 CTDB_CONTROL_TCP_ADD,
						 0, CTDB_CTRL_FLAG_NOREPLY, data, NULL, NULL);
		}
	}

	/* 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;
	char *ip = inet_ntoa(pip->sin.sin_addr);

	/* update out node table */
	ctdb->nodes[pip->vnn]->takeover_vnn = pip->takeover_vnn;

	if (!ctdb_sys_have_ip(ip)) {
		return 0;
	}

	DEBUG(0,("Release of IP %s/%u on interface %s\n", 
		 ip, ctdb->nodes[ctdb->vnn]->public_netmask_bits, 
		 ctdb->takeover.interface));

	/* stop any previous arps */
	talloc_free(ctdb->takeover.last_ctx);
	ctdb->takeover.last_ctx = NULL;

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

	state->c = talloc_steal(state, c);
	state->sin = talloc(state, struct sockaddr_in);       
	CTDB_NO_MEMORY(ctdb, state->sin);
	*state->sin = pip->sin;

	ctdb_stop_monitoring(ctdb);

	ret = ctdb_event_script_callback(ctdb, 
					 timeval_current_ofs(ctdb->tunable.script_timeout, 0),
					 state, release_ip_callback, state,
					 "releaseip %s %s %u",
					 ctdb->takeover.interface, 
					 ip,
					 ctdb->nodes[ctdb->vnn]->public_netmask_bits);
	if (ret != 0) {
		DEBUG(0,(__location__ " Failed to release IP %s on interface %s\n",
			 ip, ctdb->takeover.interface));
		talloc_free(state);
		return -1;
	}

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

	return 0;
}


/*
  setup the event script
*/
int ctdb_set_event_script(struct ctdb_context *ctdb, const char *script)
{
	ctdb->takeover.event_script = talloc_strdup(ctdb, script);
	CTDB_NO_MEMORY(ctdb, ctdb->takeover.event_script);
	return 0;
}

/*
  setup the public address list 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--;
	}

	if (nlines != ctdb->num_nodes) {
		DEBUG(0,("Number of lines in %s does not match number of nodes!\n", alist));
		talloc_free(lines);
		return -1;
	}

	for (i=0;i<nlines;i++) {
		char *p;
		struct in_addr in;

		ctdb->nodes[i]->public_address = talloc_strdup(ctdb->nodes[i], lines[i]);
		CTDB_NO_MEMORY(ctdb, ctdb->nodes[i]->public_address);
		ctdb->nodes[i]->takeover_vnn = -1;

		/* see if they supplied a netmask length */
		p = strchr(ctdb->nodes[i]->public_address, '/');
		if (!p) {
			DEBUG(0,("You must supply a netmask for public address %s\n",
				 ctdb->nodes[i]->public_address));
			return -1;
		}
		*p = 0;
		ctdb->nodes[i]->public_netmask_bits = atoi(p+1);

		if (ctdb->nodes[i]->public_netmask_bits > 32) {
			DEBUG(0, ("Illegal netmask for IP %s\n", ctdb->nodes[i]->public_address));
			return -1;
		}

		if (inet_aton(ctdb->nodes[i]->public_address, &in) == 0) {