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/*
ctdb_message protocol code
Copyright (C) Andrew Tridgell 2007
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
see http://wiki.samba.org/index.php/Samba_%26_Clustering for
protocol design and packet details
*/
#include "includes.h"
#include "lib/events/events.h"
#include "lib/tdb/include/tdb.h"
#include "system/network.h"
#include "system/filesys.h"
#include "../include/ctdb_private.h"
#include "lib/util/dlinklist.h"
/*
this dispatches the messages to the registered ctdb message handler
*/
static int ctdb_dispatch_message(struct ctdb_context *ctdb, uint32_t srvid, TDB_DATA data)
{
struct ctdb_message_list *ml;
/* XXX we need a must faster way of finding the matching srvid
- maybe a tree? */
for (ml=ctdb->message_list;ml;ml=ml->next) {
if (ml->srvid == srvid || ml->srvid == CTDB_SRVID_ALL) break;
}
if (ml == NULL) {
DEBUG(1,(__location__ " daemon vnn:%d no msg handler for srvid=%u\n",
ctdb_get_vnn(ctdb), srvid));
/* no registered message handler */
return -1;
}
ml->message_handler(ctdb, srvid, data, ml->message_private);
return 0;
}
/*
called when a CTDB_REQ_MESSAGE packet comes in
*/
void ctdb_request_message(struct ctdb_context *ctdb, struct ctdb_req_header *hdr)
{
struct ctdb_req_message *c = (struct ctdb_req_message *)hdr;
TDB_DATA data;
data.dptr = &c->data[0];
data.dsize = c->datalen;
ctdb_dispatch_message(ctdb, c->srvid, data);
}
/*
this local messaging handler is ugly, but is needed to prevent
recursion in ctdb_send_message() when the destination node is the
same as the source node
*/
struct ctdb_local_message {
struct ctdb_context *ctdb;
uint32_t srvid;
TDB_DATA data;
};
static void ctdb_local_message_trigger(struct event_context *ev, struct timed_event *te,
struct timeval t, void *private_data)
{
struct ctdb_local_message *m = talloc_get_type(private_data,
struct ctdb_local_message);
int res;
res = ctdb_dispatch_message(m->ctdb, m->srvid, m->data);
if (res != 0) {
DEBUG(0, (__location__ " Failed to dispatch message for srvid=%u\n", m->srvid));
}
talloc_free(m);
}
static int ctdb_local_message(struct ctdb_context *ctdb, uint32_t srvid, TDB_DATA data)
{
struct ctdb_local_message *m;
m = talloc(ctdb, struct ctdb_local_message);
CTDB_NO_MEMORY(ctdb, m);
m->ctdb = ctdb;
m->srvid = srvid;
m->data = data;
m->data.dptr = talloc_memdup(m, m->data.dptr, m->data.dsize);
if (m->data.dptr == NULL) {
talloc_free(m);
return -1;
}
/* this needs to be done as an event to prevent recursion */
event_add_timed(ctdb->ev, m, timeval_zero(), ctdb_local_message_trigger, m);
return 0;
}
/*
send a ctdb message
*/
int ctdb_daemon_send_message(struct ctdb_context *ctdb, uint32_t vnn,
uint32_t srvid, TDB_DATA data)
{
struct ctdb_req_message *r;
int len;
/* see if this is a message to ourselves */
if (vnn == ctdb->vnn && !(ctdb->flags & CTDB_FLAG_SELF_CONNECT)) {
return ctdb_local_message(ctdb, srvid, data);
}
len = offsetof(struct ctdb_req_message, data) + data.dsize;
r = ctdb->methods->allocate_pkt(ctdb, len);
CTDB_NO_MEMORY(ctdb, r);
talloc_set_name_const(r, "req_message packet");
r->hdr.length = len;
r->hdr.ctdb_magic = CTDB_MAGIC;
r->hdr.ctdb_version = CTDB_VERSION;
r->hdr.operation = CTDB_REQ_MESSAGE;
r->hdr.destnode = vnn;
r->hdr.srcnode = ctdb->vnn;
r->hdr.reqid = 0;
r->srvid = srvid;
r->datalen = data.dsize;
memcpy(&r->data[0], data.dptr, data.dsize);
ctdb_queue_packet(ctdb, &r->hdr);
talloc_free(r);
return 0;
}
/*
when a client goes away, we need to remove its srvid handler from the list
*/
static int message_handler_destructor(struct ctdb_message_list *m)
{
DLIST_REMOVE(m->ctdb->message_list, m);
return 0;
}
/*
setup handler for receipt of ctdb messages from ctdb_send_message()
*/
int ctdb_register_message_handler(struct ctdb_context *ctdb,
TALLOC_CTX *mem_ctx,
uint32_t srvid,
ctdb_message_fn_t handler,
void *private_data)
{
struct ctdb_message_list *m;
m = talloc(mem_ctx, struct ctdb_message_list);
CTDB_NO_MEMORY(ctdb, m);
m->ctdb = ctdb;
m->srvid = srvid;
m->message_handler = handler;
m->message_private = private_data;
DLIST_ADD(ctdb->message_list, m);
talloc_set_destructor(m, message_handler_destructor);
return 0;
}
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