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…stname

changes with mDNSResponder (Issue #282)
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@michaelrsweet
michaelrsweet committed Jul 28, 2023
1 parent ed24552 commit f91eab7
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3 changes: 2 additions & 1 deletion pappl/dnssd-private.h
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
//
// Private DNS-SD header file for the Printer Application Framework
//
// Copyright © 2019-2022 by Michael R Sweet.
// Copyright © 2019-2023 by Michael R Sweet.
// Copyright © 2010-2019 by Apple Inc.
//
// Licensed under Apache License v2.0. See the file "LICENSE" for more
Expand Down Expand Up @@ -49,6 +49,7 @@ typedef void *_pappl_dns_sd_t; // DNS-SD master reference
// Functions...
//

extern const char *_papplDNSSDCopyHostName(char *buffer, size_t bufsize) _PAPPL_PRIVATE;
extern int _papplDNSSDGetHostChanges(void) _PAPPL_PRIVATE;
extern _pappl_dns_sd_t _papplDNSSDInit(pappl_system_t *system) _PAPPL_PRIVATE;
extern void _papplDNSSDLock(void) _PAPPL_PRIVATE;
Expand Down
222 changes: 129 additions & 93 deletions pappl/dnssd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -13,11 +13,6 @@
//

#include "pappl-private.h"
#ifdef __APPLE__
# include <nameser.h>
# include <CoreFoundation/CoreFoundation.h>
# include <SystemConfiguration/SystemConfiguration.h>
#endif // __APPLE__


//
Expand All @@ -33,10 +28,16 @@
// Local globals...
//

static int pappl_dns_sd_host_name_changes = 0;
static char pappl_dns_sd_hostname[256] = "";
// Current DNS-SD hostname
static int pappl_dns_sd_hostname_changes = 0;
// Number of host name changes/collisions
static pthread_mutex_t pappl_dns_sd_host_name_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t pappl_dns_sd_hostname_mutex = PTHREAD_MUTEX_INITIALIZER;
// Host name mutex
#ifdef HAVE_MDNSRESPONDER
static DNSServiceRef pappl_dns_sd_hostname_ref = NULL;
// Host name query reference
#endif // HAVE_MDNSRESPONDER
static _pappl_dns_sd_t pappl_dns_sd_master = NULL;
// DNS-SD master reference
static pthread_mutex_t pappl_dns_sd_mutex = PTHREAD_MUTEX_INITIALIZER;
Expand All @@ -45,21 +46,15 @@ static pthread_mutex_t pappl_dns_sd_mutex = PTHREAD_MUTEX_INITIALIZER;
static AvahiThreadedPoll *pappl_dns_sd_poll = NULL;
// Avahi background thread
#endif // HAVE_AVAHI
#ifdef __APPLE__
static SCDynamicStoreRef pappl_dns_sd_sc = NULL;
// Apple system configuration data store
#endif // __APPLE__


//
// Local functions...
//

#ifdef __APPLE__
static void apple_sc_cb(SCDynamicStoreRef sc, CFArrayRef changed, void *unused);
#endif // __APPLE__
static void dns_sd_geo_to_loc(const char *geo, unsigned char loc[16]);
#ifdef HAVE_MDNSRESPONDER
static void DNSSD_API dns_sd_hostname_callback(DNSServiceRef ref, DNSServiceFlags flags, uint32_t if_index, DNSServiceErrorType error, const char *fullname, uint16_t rrtype, uint16_t rrclass, uint16_t rdlen, const void *rdata, uint32_t ttl, void *context);
static void DNSSD_API dns_sd_printer_callback(DNSServiceRef sdRef, DNSServiceFlags flags, DNSServiceErrorType errorCode, const char *name, const char *regtype, const char *domain, pappl_printer_t *printer);
static void *dns_sd_run(void *data);
static void DNSSD_API dns_sd_system_callback(DNSServiceRef sdRef, DNSServiceFlags flags, DNSServiceErrorType errorCode, const char *name, const char *regtype, const char *domain, pappl_system_t *system);
Expand All @@ -70,6 +65,25 @@ static void dns_sd_system_callback(AvahiEntryGroup *p, AvahiEntryGroupState sta
#endif // HAVE_MDNSRESPONDER


//
// '_papplDNSSDCopyHostName()' - Copy the current DNS-SD hostname.
//

const char * // O - Current DNS-SD hostname
_papplDNSSDCopyHostName(char *buffer, // I - Hostname buffer
size_t bufsize) // I - Size of hostname buffer
{
pthread_mutex_lock(&pappl_dns_sd_hostname_mutex);
if (pappl_dns_sd_hostname[0])
papplCopyString(buffer, pappl_dns_sd_hostname, bufsize);
else
httpGetHostname(NULL, buffer, (cups_len_t)bufsize);
pthread_mutex_unlock(&pappl_dns_sd_hostname_mutex);

return (buffer);
}


//
// '_papplDNSSDGetHostChanges()' - Get the number of host name changes/collisions so far.
//
Expand All @@ -80,9 +94,9 @@ _papplDNSSDGetHostChanges(void)
int changes; // Return value


pthread_mutex_lock(&pappl_dns_sd_host_name_mutex);
changes = pappl_dns_sd_host_name_changes;
pthread_mutex_unlock(&pappl_dns_sd_host_name_mutex);
pthread_mutex_lock(&pappl_dns_sd_hostname_mutex);
changes = pappl_dns_sd_hostname_changes;
pthread_mutex_unlock(&pappl_dns_sd_hostname_mutex);

return (changes);
}
Expand All @@ -109,25 +123,28 @@ _papplDNSSDInit(
return (pappl_dns_sd_master);
}

# ifdef __APPLE__
// Use the system configuration dynamic store for host info...
SCDynamicStoreContext scinfo; // Information for callback

memset(&scinfo, 0, sizeof(scinfo));

pappl_dns_sd_sc = SCDynamicStoreCreate(kCFAllocatorDefault, CFSTR("libpappl"), (SCDynamicStoreCallBack)apple_sc_cb, &scinfo);
# endif // __APPLE__

if ((error = DNSServiceCreateConnection(&pappl_dns_sd_master)) == kDNSServiceErr_NoError)
{
// Start a query for the 1.0.0.127 PTR record (localhost)
httpGetHostname(NULL, pappl_dns_sd_hostname, sizeof(pappl_dns_sd_hostname));

pappl_dns_sd_hostname_ref = pappl_dns_sd_master;
if ((error = DNSServiceQueryRecord(&pappl_dns_sd_hostname_ref, kDNSServiceFlagsShareConnection, kDNSServiceInterfaceIndexLocalOnly, "1.0.0.127.in-addr.arpa.", kDNSServiceType_PTR, kDNSServiceClass_IN, dns_sd_hostname_callback, NULL)) != kDNSServiceErr_NoError)
{
papplLog(system, PAPPL_LOGLEVEL_ERROR, "Unable to query PTR record for local hostname: %s", _papplDNSSDStrError(error));
pappl_dns_sd_hostname_ref = NULL;
}

if (pthread_create(&tid, NULL, dns_sd_run, system))
{
papplLog(system, PAPPL_LOGLEVEL_ERROR, "Unable to create DNS-SD thread: %s", strerror(errno));
DNSServiceRefDeallocate(pappl_dns_sd_master);
pappl_dns_sd_master = NULL;
}
else
{
pthread_detach(tid);
}
}
else
{
Expand Down Expand Up @@ -164,6 +181,15 @@ _papplDNSSDInit(
}
else
{
// Get the current mDNS hostname...
const char *dns_sd_hostname = avahi_client_get_host_name_fqdn(pappl_dns_sd_master);
// mDNS hostname

if (dns_sd_hostname)
papplCopyString(pappl_dns_sd_hostname, dns_sd_hostname, sizeof(pappl_dns_sd_hostname));
else
httpGetHostname(NULL, pappl_dns_sd_hostname, sizeof(pappl_dns_sd_hostname));

// Start the background thread...
avahi_threaded_poll_start(pappl_dns_sd_poll);
}
Expand Down Expand Up @@ -544,7 +570,7 @@ _papplPrinterRegisterDNSSDNoLock(

printer->dns_sd_printer_ref = master;

if ((error = DNSServiceRegister(&printer->dns_sd_printer_ref, kDNSServiceFlagsShareConnection | kDNSServiceFlagsNoAutoRename, if_index, printer->dns_sd_name, "_printer._tcp", NULL /* domain */, NULL /* host */, 0 /* port */, 0 /* txtLen */, NULL /* txtRecord */, (DNSServiceRegisterReply)dns_sd_printer_callback, printer)) != kDNSServiceErr_NoError)
if ((error = DNSServiceRegister(&printer->dns_sd_printer_ref, kDNSServiceFlagsShareConnection | kDNSServiceFlagsNoAutoRename, if_index, printer->dns_sd_name, "_printer._tcp", NULL /* domain */, system->hostname, 0 /* port */, 0 /* txtLen */, NULL /* txtRecord */, (DNSServiceRegisterReply)dns_sd_printer_callback, printer)) != kDNSServiceErr_NoError)
{
papplLogPrinter(printer, PAPPL_LOGLEVEL_ERROR, "Unable to register '%s._printer._tcp': %s", printer->dns_sd_name, _papplDNSSDStrError(error));
ret = false;
Expand Down Expand Up @@ -1135,39 +1161,6 @@ _papplSystemUnregisterDNSSDNoLock(
}


#ifdef __APPLE__
//
// 'apple_sc_cb()' - Track host name changes.
//

static void
apple_sc_cb(SCDynamicStoreRef sc, // I - Dynamic store context
CFArrayRef changed, // I - Changed keys
void *unused) // I - Context pointer (unused)
{
CFIndex i, // Looping var
count; // Number of values


(void)sc;
(void)unused;

// See if we had a local hostname change - anything else will be a network
// change...
for (i = 0, count = CFArrayGetCount(changed); i < count; i ++)
{
if (CFArrayGetValueAtIndex(changed, i) == kSCPropNetLocalHostName)
{
pthread_mutex_lock(&pappl_dns_sd_host_name_mutex);
pappl_dns_sd_host_name_changes ++;
pthread_mutex_unlock(&pappl_dns_sd_host_name_mutex);
break;
}
}
}
#endif // __APPLE__


//
// 'dns_sd_geo_to_loc()' - Convert a "geo:" URI to a DNS LOC record.
//
Expand Down Expand Up @@ -1212,6 +1205,79 @@ dns_sd_geo_to_loc(const char *geo, // I - "geo:" URI


#ifdef HAVE_MDNSRESPONDER
//
// 'dns_sd_hostname_callback()' - Track changes to the mDNS hostname...
//

static void DNSSD_API
dns_sd_hostname_callback(
DNSServiceRef ref, // I - Service reference (unsued)
DNSServiceFlags flags, // I - Flags (unused)
uint32_t if_index, // I - Interface index (unused)
DNSServiceErrorType error, // I - Error code, if any
const char *fullname, // I - Search name (unused)
uint16_t rrtype, // I - Record type (unused)
uint16_t rrclass, // I - Record class (unused)
uint16_t rdlen, // I - Record data length
const void *rdata, // I - Record data
uint32_t ttl, // I - Time-to-live (unused)
void *context) // I - Context (unused)
{
uint8_t *rdataptr, // Pointer into record data
lablen; // Length of current label
char temp[1024], // Temporary hostname string
*tempptr; // Pointer into temporary string


(void)ref;
(void)flags;
(void)if_index;
(void)fullname;
(void)rrtype;
(void)rrclass;
(void)ttl;
(void)context;

// Check for errors...
if (error != kDNSServiceErr_NoError)
return;

// Copy the hostname from the PTR record...
for (rdataptr = (uint8_t *)rdata, tempptr = temp; rdlen > 0 && tempptr < (temp + sizeof(temp) - 2); rdlen -= lablen, rdataptr += lablen)
{
lablen = *rdataptr++;
rdlen --;

if (!rdlen || rdlen < lablen)
break;

if (tempptr > temp)
*tempptr++ = '.';

if (lablen < (sizeof(temp) - (size_t)(tempptr - temp)))
{
memcpy(tempptr, rdataptr, lablen);
tempptr += lablen;
}
}

*tempptr = '\0';

// Ignore localhost...
if (!strcmp(temp, "localhost"))
return;

// Look for changes to the hostname...
pthread_mutex_lock(&pappl_dns_sd_hostname_mutex);
if (strcmp(temp, pappl_dns_sd_hostname))
{
papplCopyString(pappl_dns_sd_hostname, temp, sizeof(pappl_dns_sd_hostname));
pappl_dns_sd_hostname_changes ++;
}
pthread_mutex_unlock(&pappl_dns_sd_hostname_mutex);
}


//
// 'dns_sd_printer_callback()' - Handle DNS-SD printer registration events.
//
Expand Down Expand Up @@ -1261,17 +1327,8 @@ dns_sd_run(void *data) // I - System object
pappl_system_t *system = (pappl_system_t *)data;
// System object
struct pollfd pfd; // Poll data
# ifndef __APPLE__
time_t curtime, // Current time
hosttime = 0; // Hostname update time
char prevhost[256], // Previous hostname
curhost[256]; // Current hostname


if (gethostname(prevhost, sizeof(prevhost)))
prevhost[0] = '\0';
# endif // !__APPLE__

pfd.events = POLLIN | POLLERR;
pfd.fd = DNSServiceRefSockFD(pappl_dns_sd_master);

Expand All @@ -1288,27 +1345,6 @@ dns_sd_run(void *data) // I - System object
break;
}

# ifndef __APPLE__
if (hosttime != time(&curtime))
{
// Check for hostname changes no more than once per second...
hosttime = curtime;

if (gethostname(curhost, sizeof(curhost)))
curhost[0] = '\0';

if (strcmp(curhost, prevhost))
{
// Flag the hostname change...
papplCopyString(prevhost, curhost, sizeof(prevhost));

pthread_mutex_lock(&pappl_dns_sd_host_name_mutex);
pappl_dns_sd_host_name_changes ++;
pthread_mutex_unlock(&pappl_dns_sd_host_name_mutex);
}
}
# endif // !__APPLE__

if (pfd.revents & POLLIN)
{
// Read DNS-SD data...
Expand Down Expand Up @@ -1391,9 +1427,9 @@ dns_sd_client_cb(
}
else if (state == AVAHI_CLIENT_S_RUNNING)
{
pthread_mutex_lock(&pappl_dns_sd_host_name_mutex);
pappl_dns_sd_host_name_changes ++;
pthread_mutex_unlock(&pappl_dns_sd_host_name_mutex);
pthread_mutex_lock(&pappl_dns_sd_hostname_mutex);
pappl_dns_sd_hostname_changes ++;
pthread_mutex_unlock(&pappl_dns_sd_hostname_mutex);
}
}

Expand Down
14 changes: 2 additions & 12 deletions pappl/system-accessors.c
View file
Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
//
// System accessor functions for the Printer Application Framework
//
// Copyright © 2020-2022 by Michael R Sweet.
// Copyright © 2020-2023 by Michael R Sweet.
//
// Licensed under Apache License v2.0. See the file "LICENSE" for more
// information.
Expand Down Expand Up @@ -1774,17 +1774,7 @@ _papplSystemSetHostNameNoLock(
}
else
{
#ifdef HAVE_AVAHI
_pappl_dns_sd_t master = _papplDNSSDInit(system);
// DNS-SD master reference
const char *avahi_name = master ? avahi_client_get_host_name_fqdn(master) : NULL;
// mDNS hostname

if (avahi_name)
papplCopyString(temp, avahi_name, sizeof(temp));
else
#endif /* HAVE_AVAHI */
httpGetHostname(NULL, temp, sizeof(temp));
_papplDNSSDCopyHostName(temp, sizeof(temp));

if ((ptr = strstr(temp, ".lan")) != NULL && !ptr[4])
{
Expand Down

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