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/*
Unix SMB/CIFS implementation.
DNS-SD registration
Copyright (C) Rishi Srivatsavai 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>
/* Uses DNS service discovery (libdns_sd) to
* register the SMB service. SMB service is registered
* on ".local" domain via Multicast DNS & any
* other unicast DNS domains available.
*
* Users use the smbclient -B (Browse) option to
* browse for advertised SMB services.
*/
#define DNS_REG_RETRY_INTERVAL (5*60) /* in seconds */
#ifdef WITH_DNSSD_SUPPORT
#include <dns_sd.h>
struct dns_reg_state {
DNSServiceRef srv_ref;
struct timed_event *retry_handler;
};
void dns_register_close(struct dns_reg_state **dns_state_ptr)
{
struct dns_reg_state *dns_state = *dns_state_ptr;
if (dns_state == NULL) {
return;
}
if (dns_state->srv_ref != NULL) {
/* Close connection to the mDNS daemon */
DNSServiceRefDeallocate(dns_state->srv_ref);
dns_state->srv_ref = NULL;
}
/* Clear event handler */
if (dns_state->retry_handler != NULL) {
TALLOC_FREE(dns_state->retry_handler);
dns_state->retry_handler = NULL;
}
talloc_free(dns_state);
*dns_state_ptr = NULL;
}
static void dns_register_smbd_retry(struct event_context *ctx,
struct timed_event *te,
const struct timeval *now,
void *private_data)
{
struct dns_reg_state *dns_state = (struct dns_reg_state *)private_data;
/* Clear previous registration state to force new
* registration attempt. Clears event handler.
*/
dns_register_close(&dns_state);
}
static void schedule_dns_register_smbd_retry(struct dns_reg_state *dns_state,
struct timeval *timeout)
{
struct timed_event * event;
dns_state->srv_ref = NULL;
event= event_add_timed(smbd_event_context(),
NULL,
timeval_current_ofs(DNS_REG_RETRY_INTERVAL, 0),
"DNS registration handler",
dns_register_smbd_retry,
dns_state);
dns_state->retry_handler = event;
get_timed_events_timeout(smbd_event_context(), timeout);
}
/* Kick off a mDNS request to register the "_smb._tcp" on the specified port.
* We really ought to register on all the ports we are listening on. This will
* have to be an exercise for some-one who knows the DNS registration API a bit
* better.
*/
void dns_register_smbd(struct dns_reg_state ** dns_state_ptr,
unsigned port,
int *maxfd,
fd_set *listen_set,
struct timeval *timeout)
{
int mdnsd_conn_fd;
DNSServiceErrorType err;
struct dns_reg_state *dns_state = *dns_state_ptr;
if (dns_state == NULL) {
*dns_state_ptr = dns_state = talloc(NULL, struct dns_reg_state);
if (dns_state == NULL) {
return;
}
}
/* Quit if a re-try attempt has been scheduled. */
if (dns_state->retry_handler != NULL) {
return;
}
/* If a registration is active add conn
* fd to select listen_set and return
*/
if (dns_state->srv_ref != NULL) {
mdnsd_conn_fd = DNSServiceRefSockFD(dns_state->srv_ref);
FD_SET(mdnsd_conn_fd, listen_set);
return;
}
DEBUG(6, ("registering _smb._tcp service on port %d\n", port));
/* Register service with DNS. Connects with the mDNS
* daemon running on the local system to perform DNS
* service registration.
*/
err = DNSServiceRegister(&dns_state->srv_ref, 0 /* flags */,
kDNSServiceInterfaceIndexAny,
NULL /* service name */,
"_smb._tcp" /* service type */,
NULL /* domain */,
"" /* SRV target host name */,
htons(port),
0 /* TXT record len */,
NULL /* TXT record data */,
NULL /* callback func */,
NULL /* callback context */);
if (err != kDNSServiceErr_NoError) {
/* Failed to register service. Schedule a re-try attempt.
*/
DEBUG(3, ("unable to register with mDNS (err %d)\n", err));
schedule_dns_register_smbd_retry(dns_state, timeout);
return;
}
mdnsd_conn_fd = DNSServiceRefSockFD(dns_state->srv_ref);
FD_SET(mdnsd_conn_fd, listen_set);
*maxfd = MAX(*maxfd, mdnsd_conn_fd);
*timeout = timeval_zero();
}
/* Processes reply from mDNS daemon. Returns true if a reply was received */
bool dns_register_smbd_reply(struct dns_reg_state *dns_state,
fd_set *lfds, struct timeval *timeout)
{
int mdnsd_conn_fd = -1;
if (dns_state->srv_ref == NULL) {
return false;
}
mdnsd_conn_fd = DNSServiceRefSockFD(dns_state->srv_ref);
/* Process reply from daemon. Handles any errors. */
if ((mdnsd_conn_fd != -1) && (FD_ISSET(mdnsd_conn_fd,lfds)) ) {
DNSServiceErrorType err;
err = DNSServiceProcessResult(dns_state->srv_ref);
if (err != kDNSServiceErr_NoError) {
DEBUG(3, ("failed to process mDNS result (err %d), re-trying\n",
err));
schedule_dns_register_smbd_retry(dns_state, timeout);
}
return true;
}
return false;
}
#else /* WITH_DNSSD_SUPPORT */
void dns_register_smbd(struct dns_reg_state ** dns_state_ptr,
unsigned port,
int *maxfd,
fd_set *listen_set,
struct timeval *timeout)
{}
void dns_register_close(struct dns_reg_state ** dns_state_ptr)
{}
bool dns_register_smbd_reply(struct dns_reg_state *dns_state,
fd_set *lfds, struct timeval *timeout)
{
return false;
}
#endif /* WITH_DNSSD_SUPPORT */
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