usr.lib/mdnsd/mDNSPosix.c

11  * Unless required by applicable law or agreed to in writing, software
23  * should be indented to the same level as everything else in that compound statement.
28  * layout leads people to unfortunate misunderstandings about how the C language really works.)
43 <rdar://problem/4403128> Cap number of "sendto failed" messages we allow mDNSResponder to log
59 Ignore multicasts accidentally delivered to our unicast receiving socket
62 Move ParseDNSServers() from PosixDaemon.c to mDNSPosix.c so all Posix client layers can use it
65 Need to #include "dns_sd.h"
83 instead of having to call through to the daemon via IPC to get this information.
101 Renamed mDNSClientAPI.h to mDNSEmbeddedAPI.h
102   The name "mDNSClientAPI.h" is misleading to new developers looking at this code. The interfaces
103   declared in that file are ONLY appropriate to single-address-space embedded applications.
107 For consistency with AllDNSLinkGroupv6, rename AllDNSLinkGroup to AllDNSLinkGroupv4
110 Rename mDNSPlatformInit_ReceiveUnicast to mDNSPlatformInit_CanReceiveUnicast
119 <rdar://problem/3801296> Need to seed random number generator from platform-layer data
122 Fix Posix build - change mDNS_SetFQDNs to mDNS_SetFQDN, remove unicast
128 Convert ServiceRegDomain to domainname instead of C string
138 NOT_HAVE_SA_LEN applies to v6, too. And use more-portable s6_addr.
141 Changes to fix the Posix build on Solaris.
148 from mDNSMacOSX.h to mDNSEmbeddedAPI.h), impelemted to return "local"
149 only on non-OSX platforms.  Changed call to return a copy of the list
150 to avoid shared memory issues.  Added a routine to free the list.
153 To reduce future confusion, renamed 'TxAndRx' to 'McastTxRx'
159 Make sure to set the McastTxRx field so that duplicate suppression works correctly
171 <rdar://problem/3541288>: Time to prune obsolete code for listening on port 53
180 For consistency, rename multicastSocket to multicastSocket4, and multicastSocketv6 to multicastSocket6
186 <rdar://problem/3448144>: Don't try to receive unicast responses if we're not the first to bind to the UDP port
192 Respond to If changes by rebuilding interface list.
208 Best solution is just to combine mDNSEmbeddedAPI.h and mDNSPlatformFunctions.h into a single file.
217 Update to APSL 2.0
220 LogMsg() errors are serious -- always report them to stderr, regardless of debugging level
226 Update code to compile with the new mDNSCoreReceive() function that requires a TTL
230 Add generic MemAllocate/MemFree prototypes to mDNSPlatformFunctions.h,
231 and add the obvious trivial implementations to each platform support layer
237 There's not much point running mDNS over a point-to-point link; exclude those
261 <rdar://problem/3240002> mDNS_RegisterNoSuchService needs to include a host name
264 Fixes done at IETF 56 to make mDNSProxyResponderPosix run on Solaris
267 Change type called "mDNSOpaqueID" to the more descriptive name "mDNSInterfaceID"
270 Fixes to make the code build on Linux
273 Switched to using new "mDNS_Execute" model (see "mDNSCore/Implementer Notes.txt")
286 mDNS_snprintf() doesn't need to be in a separate file
294 #include "mDNSEmbeddedAPI.h"           // Defines the interface provided to the client layer above
295 #include "mDNSPosix.h"				 // Defines the specific types needed to run mDNS on this platform
349 // Note that static data is initialized to zero in (modern) C.
409 // mDNS core calls this routine when it needs to send a packet.
414 	struct sockaddr_storage to;
426 		struct sockaddr_in *sin = (struct sockaddr_in*)&to;
439 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)&to;
452 		err = sendto(sendingsocket, msg, (char*)end - (char*)msg, 0, (struct sockaddr *)&to, GET_SA_LEN(to));
458         // Don't report EHOSTDOWN (i.e. ARP failure), ENETDOWN, or no route to host for unicast destinations
466 				LogMsg("mDNSPlatformSendUDP got error %d (%s) sending packet to %#a on interface %#a/%s/%d",
469 				LogMsg("mDNSPlatformSendUDP got error %d (%s) sending packet to %#a", errno, strerror(errno), dst);
504 		// I've only seen this on OpenBSD) then apply a hack to
506 		// Basically what we do is check to see whether the
508 		// destAddr to the mDNS address.
512 		// but I'm at a loss as to how.
515 		// no way to tell the destination address or interface this packet arrived on,
531 		// to "" if the name isn't available, or the index to -1
538 			// Ignore multicasts accidentally delivered to our unicast receiving socket
548 				verbosedebugf("SocketDataReady ignored a packet from %#a to %#a on interface %s/%d expecting %#a/%s/%d/%d",
564 				verbosedebugf("SocketDataReady got a packet from %#a to %#a on interface %#a/%s/%d/%d",
647 // or they can alternatively just require all registering services to provide an explicit name
665 		line[255]='\0';		// just to be safe
682 // Returns a pointer to if it found, or NULL otherwise.
790 			#error This platform has no way to avoid address busy errors on multicast.
795 	// We want to receive destination addresses and interface identifiers.
818 				#warning This platform has no way to get the destination interface information -- will only work for single-homed hosts
825 			// We no longer depend on being able to get the received TTL, so don't worry if the option fails
853 		// There's some debate as to whether IP_MULTICAST_TTL is an int or a byte so we just try both.
867 			bindAddr.sin_addr.s_addr = INADDR_ANY; // Want to receive multicasts AND unicasts on this socket
892 		#warning This platform has no way to get the destination interface information for IPv6 -- will only work for single-homed hosts
932 		// We want to receive only IPv6 packets on this socket.
948 		// There's some debate as to whether IPV6_MULTICAST_HOPS is an int or a byte so we just try both.
967 			bindAddr6.sin6_addr        = in6addr_any; // Want to receive multicasts AND unicasts on this socket
975 	// Set the socket to non-blocking.
1054 	// The interface is all ready to go, let's register it with the mDNS core.
1068 		// Use intfName instead of intf->intfName in the next line to avoid dereferencing NULL.
1069 		debugf("SetupOneInterface: %s %#a failed to register %d", intfName, &intf->coreIntf.ip, err);
1078 // Call get_ifi_info() to obtain a list of active interfaces and call SetupOneInterface() on each one.
1092 	if (err == 0)		/* Link the IPv6 list to the end of the IPv4 list */
1128 		// Temporary workaround: Multicast loopback on IPv6 interfaces appears not to work.
1129 		// In the interim, we skip loopback interface only if we found at least one v4 interface to use
1156 	// Configure read to be non-blocking because inbound msg size is not known in advance
1159 	/* Subscribe the socket to Link & IP addr notifications. */
1208 	// The structure here is more complex than it really ought to be because,
1209 	// unfortunately, there's no good way to size a buffer in advance large
1210 	// enough to hold all pending data and so avoid message fragmentation.
1221 			if ( buff < (char*) pNLMsg)		// we have space to shuffle
1246 		// Advance pNLMsg to the next message in the buffer
1269 	// Configure read to be non-blocking because inbound msg size is not known in advance
1338 	// detected. If this ever proves to be a performance issue in a multi-homed
1339 	// configuration, more care should be paid to changedInterfaces.
1344 // Register with either a Routing Socket or RtNetLink to listen for interface changes.
1362 // Test to see if we're the first client running on UDP port 5353, by trying to bind to 5353 without using SO_REUSEPORT.
1364 // we just need to be aware that we shouldn't expect to successfully receive unicast UDP responses.
1380 // mDNS core calls this routine to initialise the platform-specific data.
1421 		// Failure to observe interface changes is non-fatal.
1424 			fprintf(stderr, "mDNS(%d) WARNING: Unable to detect interface changes (%d).\n", getpid(), err);
1438 // mDNS core calls this routine to clean up the platform-specific data.
1439 // In our case all we need to do is to tear down every network interface.
1465 // mDNS core calls this routine when it wants to prevent
1473 // mDNSPlatformLock and allow the platform to reenter mDNS core code.
1483 // mDNS core calls this routine to copy C strings.
1484 // On the Posix platform this maps directly to the ANSI C strcpy.
1490 // mDNS core calls this routine to get the length of a C string.
1491 // On the Posix platform this maps directly to the ANSI C strlen.
1497 // mDNS core calls this routine to copy memory.
1498 // On the Posix platform this maps directly to the ANSI C memcpy.
1504 // mDNS core calls this routine to test whether blocks of memory are byte-for-byte
1511 // mDNS core calls this routine to clear blocks of memory.
1534 	// We should find a better way to do this
1543 	// tv.tv_usec is microseconds since the start of this second (i.e. values 0 to 999999)
1545 	// and we multiply tv.tv_usec by 16 / 15625 to get a value in the range 0-1023 to go in the bottom 10 bits.
1567 	// 1. Call mDNS_Execute() to let mDNSCore do what it needs to do
1585 	// 3. Calculate the time remaining to the next scheduled event (in struct timeval format)
1646 // Add a file descriptor to the set that mDNSPosixRunEventLoopOnce() listens to.
1675 // Remove a file descriptor from the set that mDNSPosixRunEventLoopOnce() listens to.
1700 // Tell the event package to listen for signal and report it in mDNSPosixRunEventLoopOnce().
1715 // Tell the event package to stop listening for signal in mDNSPosixRunEventLoopOnce().
1730 // Do a single pass through the attendent event sources and dispatch any found to their callbacks.
1739 	// Include the sockets that are listening to the wire in our select() set
1751 		(void) mDNSPosixProcessFDSet( m, &listenFDs);	// call this first to process wire data for clients