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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>
#include "smbd/smbd.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 {
struct tevent_context *event_ctx;
uint16_t port;
DNSServiceRef srv_ref;
struct tevent_timer *te;
int fd;
struct tevent_fd *fde;
};
static int dns_reg_state_destructor(struct dns_reg_state *dns_state)
{
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 */
TALLOC_FREE(dns_state->te);
TALLOC_FREE(dns_state->fde);
dns_state->fd = -1;
return 0;
}
static void dns_register_smbd_retry(struct tevent_context *ctx,
struct tevent_timer *te,
struct timeval now,
void *private_data);
static void dns_register_smbd_fde_handler(struct tevent_context *ev,
struct tevent_fd *fde,
uint16_t flags,
void *private_data);
static bool dns_register_smbd_schedule(struct dns_reg_state *dns_state,
struct timeval tval)
{
dns_reg_state_destructor(dns_state);
dns_state->te = tevent_add_timer(dns_state->event_ctx,
dns_state,
tval,
dns_register_smbd_retry,
dns_state);
if (!dns_state->te) {
return false;
}
return true;
}
static void dns_register_smbd_retry(struct tevent_context *ctx,
struct tevent_timer *te,
struct timeval now,
void *private_data)
{
struct dns_reg_state *dns_state = talloc_get_type_abort(private_data,
struct dns_reg_state);
DNSServiceErrorType err;
dns_reg_state_destructor(dns_state);
DEBUG(6, ("registering _smb._tcp service on port %d\n",
dns_state->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(dns_state->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));
goto retry;
}
dns_state->fd = DNSServiceRefSockFD(dns_state->srv_ref);
if (dns_state->fd == -1) {
goto retry;
}
dns_state->fde = tevent_add_fd(dns_state->event_ctx,
dns_state,
dns_state->fd,
TEVENT_FD_READ,
dns_register_smbd_fde_handler,
dns_state);
if (!dns_state->fde) {
goto retry;
}
return;
retry:
dns_register_smbd_schedule(dns_state,
timeval_current_ofs(DNS_REG_RETRY_INTERVAL, 0));
}
/* Processes reply from mDNS daemon. Returns true if a reply was received */
static void dns_register_smbd_fde_handler(struct tevent_context *ev,
struct tevent_fd *fde,
uint16_t flags,
void *private_data)
{
struct dns_reg_state *dns_state = talloc_get_type_abort(private_data,
struct dns_reg_state);
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));
goto retry;
}
talloc_free(dns_state);
return;
retry:
dns_register_smbd_schedule(dns_state,
timeval_current_ofs(DNS_REG_RETRY_INTERVAL, 0));
}
bool smbd_setup_mdns_registration(struct tevent_context *ev,
TALLOC_CTX *mem_ctx,
uint16_t port)
{
struct dns_reg_state *dns_state;
dns_state = talloc_zero(mem_ctx, struct dns_reg_state);
if (dns_state == NULL) {
return false;
}
dns_state->event_ctx = ev;
dns_state->port = port;
dns_state->fd = -1;
talloc_set_destructor(dns_state, dns_reg_state_destructor);
return dns_register_smbd_schedule(dns_state, timeval_zero());
}
#else /* WITH_DNSSD_SUPPORT */
bool smbd_setup_mdns_registration(struct tevent_context *ev,
TALLOC_CTX *mem_ctx,
uint16_t port)
{
return true;
}
#endif /* WITH_DNSSD_SUPPORT */
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