/* -*- Mode: C; tab-width: 4 -*-
*
* Copyright (c) 2002-2015 Apple Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#include "mDNSEmbeddedAPI.h" // Defines the interface provided to the client layer above
#include "DNSCommon.h"
#include "mDNSPosix.h" // Defines the specific types needed to run mDNS on this platform
#include "dns_sd.h"
#include "dnssec.h"
#include "nsec.h"
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <syslog.h>
#include <stdarg.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <sys/select.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <time.h> // platform support for UTC time
#if USES_NETLINK
#include <asm/types.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#else // USES_NETLINK
#include <net/route.h>
#include <net/if.h>
#endif // USES_NETLINK
#include "mDNSUNP.h"
#include "GenLinkedList.h"
#include "dnsproxy.h"
// ***************************************************************************
// Structures
// We keep a list of client-supplied event sources in PosixEventSource records
struct PosixEventSource
{
mDNSPosixEventCallback Callback;
void *Context;
int fd;
struct PosixEventSource *Next;
};
typedef struct PosixEventSource PosixEventSource;
// Context record for interface change callback
struct IfChangeRec
{
int NotifySD;
mDNS *mDNS;
};
typedef struct IfChangeRec IfChangeRec;
// Note that static data is initialized to zero in (modern) C.
static fd_set gEventFDs;
static int gMaxFD; // largest fd in gEventFDs
static GenLinkedList gEventSources; // linked list of PosixEventSource's
static sigset_t gEventSignalSet; // Signals which event loop listens for
static sigset_t gEventSignals; // Signals which were received while inside loop
static PosixNetworkInterface *gRecentInterfaces;
// ***************************************************************************
// Globals (for debugging)
static int num_registered_interfaces = 0;
static int num_pkts_accepted = 0;
static int num_pkts_rejected = 0;
// ***************************************************************************
// Functions
int gMDNSPlatformPosixVerboseLevel = 0;
#define PosixErrorToStatus(errNum) ((errNum) == 0 ? mStatus_NoError : mStatus_UnknownErr)
mDNSlocal void SockAddrTomDNSAddr(const struct sockaddr *const sa, mDNSAddr *ipAddr, mDNSIPPort *ipPort)
{
switch (sa->sa_family)
{
case AF_INET:
{
struct sockaddr_in *sin = (struct sockaddr_in*)sa;
ipAddr->type = mDNSAddrType_IPv4;
ipAddr->ip.v4.NotAnInteger = sin->sin_addr.s_addr;
if (ipPort) ipPort->NotAnInteger = sin->sin_port;
break;
}
#if HAVE_IPV6
case AF_INET6:
{
struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)sa;
#ifndef NOT_HAVE_SA_LEN
assert(sin6->sin6_len == sizeof(*sin6));
#endif
ipAddr->type = mDNSAddrType_IPv6;
ipAddr->ip.v6 = *(mDNSv6Addr*)&sin6->sin6_addr;
if (ipPort) ipPort->NotAnInteger = sin6->sin6_port;
break;
}
#endif
default:
verbosedebugf("SockAddrTomDNSAddr: Uknown address family %d\n", sa->sa_family);
ipAddr->type = mDNSAddrType_None;
if (ipPort) ipPort->NotAnInteger = 0;
break;
}
}
#if COMPILER_LIKES_PRAGMA_MARK
#pragma mark ***** Send and Receive
#endif
// mDNS core calls this routine when it needs to send a packet.
mDNSexport mStatus mDNSPlatformSendUDP(const mDNS *const m, const void *const msg, const mDNSu8 *const end,
mDNSInterfaceID InterfaceID, UDPSocket *src, const mDNSAddr *dst,
mDNSIPPort dstPort, mDNSBool useBackgroundTrafficClass)
{
int err = 0;
struct sockaddr_storage to;
PosixNetworkInterface * thisIntf = (PosixNetworkInterface *)(InterfaceID);
int sendingsocket = -1;
(void)src; // Will need to use this parameter once we implement mDNSPlatformUDPSocket/mDNSPlatformUDPClose
(void) useBackgroundTrafficClass;
assert(m != NULL);
assert(msg != NULL);
assert(end != NULL);
assert((((char *) end) - ((char *) msg)) > 0);
if (dstPort.NotAnInteger == 0)
{
LogMsg("mDNSPlatformSendUDP: Invalid argument -dstPort is set to 0");
return PosixErrorToStatus(EINVAL);
}
if (dst->type == mDNSAddrType_IPv4)
{
struct sockaddr_in *sin = (struct sockaddr_in*)&to;
#ifndef NOT_HAVE_SA_LEN
sin->sin_len = sizeof(*sin);
#endif
sin->sin_family = AF_INET;
sin->sin_port = dstPort.NotAnInteger;
sin->sin_addr.s_addr = dst->ip.v4.NotAnInteger;
sendingsocket = thisIntf ? thisIntf->multicastSocket4 : m->p->unicastSocket4;
}
#if HAVE_IPV6
else if (dst->type == mDNSAddrType_IPv6)
{
struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)&to;
mDNSPlatformMemZero(sin6, sizeof(*sin6));
#ifndef NOT_HAVE_SA_LEN
sin6->sin6_len = sizeof(*sin6);
#endif
sin6->sin6_family = AF_INET6;
sin6->sin6_port = dstPort.NotAnInteger;
sin6->sin6_addr = *(struct in6_addr*)&dst->ip.v6;
sendingsocket = thisIntf ? thisIntf->multicastSocket6 : m->p->unicastSocket6;
}
#endif
if (sendingsocket >= 0)
err = sendto(sendingsocket, msg, (char*)end - (char*)msg, 0, (struct sockaddr *)&to, GET_SA_LEN(to));
if (err > 0) err = 0;
else if (err < 0)
{
static int MessageCount = 0;
// Don't report EHOSTDOWN (i.e. ARP failure), ENETDOWN, or no route to host for unicast destinations
if (!mDNSAddressIsAllDNSLinkGroup(dst))
if (errno == EHOSTDOWN || errno == ENETDOWN || errno == EHOSTUNREACH || errno == ENETUNREACH) return(mStatus_TransientErr);
if (MessageCount < 1000)
{
MessageCount++;
if (thisIntf)
LogMsg("mDNSPlatformSendUDP got error %d (%s) sending packet to %#a on interface %#a/%s/%d",
errno, strerror(errno), dst, &thisIntf->coreIntf.ip, thisIntf->intfName, thisIntf->index);
else
LogMsg("mDNSPlatformSendUDP got error %d (%s) sending packet to %#a", errno, strerror(errno), dst);
}
}
return PosixErrorToStatus(err);
}
// This routine is called when the main loop detects that data is available on a socket.
mDNSlocal void SocketDataReady(mDNS *const m, PosixNetworkInterface *intf, int skt)
{
mDNSAddr senderAddr, destAddr;
mDNSIPPort senderPort;
ssize_t packetLen;
DNSMessage packet;
struct my_in_pktinfo packetInfo;
struct sockaddr_storage from;
socklen_t fromLen;
int flags;
mDNSu8 ttl;
mDNSBool reject;
const mDNSInterfaceID InterfaceID = intf ? intf->coreIntf.InterfaceID : NULL;
assert(m != NULL);
assert(skt >= 0);
fromLen = sizeof(from);
flags = 0;
packetLen = recvfrom_flags(skt, &packet, sizeof(packet), &flags, (struct sockaddr *) &from, &fromLen, &packetInfo, &ttl);
if (packetLen >= 0)
{
SockAddrTomDNSAddr((struct sockaddr*)&from, &senderAddr, &senderPort);
SockAddrTomDNSAddr((struct sockaddr*)&packetInfo.ipi_addr, &destAddr, NULL);
// If we have broken IP_RECVDSTADDR functionality (so far
// I've only seen this on OpenBSD) then apply a hack to
// convince mDNS Core that this isn't a spoof packet.
// Basically what we do is check to see whether the
// packet arrived as a multicast and, if so, set its
// destAddr to the mDNS address.
//
// I must admit that I could just be doing something
// wrong on OpenBSD and hence triggering this problem
// but I'm at a loss as to how.
//
// If this platform doesn't have IP_PKTINFO or IP_RECVDSTADDR, then we have
// no way to tell the destination address or interface this packet arrived on,
// so all we can do is just assume it's a multicast
#if HAVE_BROKEN_RECVDSTADDR || (!defined(IP_PKTINFO) && !defined(IP_RECVDSTADDR))
if ((destAddr.NotAnInteger == 0) && (flags & MSG_MCAST))
{
destAddr.type = senderAddr.type;
if (senderAddr.type == mDNSAddrType_IPv4) destAddr.ip.v4 = AllDNSLinkGroup_v4.ip.v4;
else if (senderAddr.type == mDNSAddrType_IPv6) destAddr.ip.v6 = AllDNSLinkGroup_v6.ip.v6;
}
#endif
// We only accept the packet if the interface on which it came
// in matches the interface associated with this socket.
// We do this match by name or by index, depending on which
// information is available. recvfrom_flags sets the name
// to "" if the name isn't available, or the index to -1
// if the index is available. This accomodates the various
// different capabilities of our target platforms.
reject = mDNSfalse;
if (!intf)
{
// Ignore multicasts accidentally delivered to our unicast receiving socket
if (mDNSAddrIsDNSMulticast(&destAddr)) packetLen = -1;
}
else
{
if (packetInfo.ipi_ifname[0] != 0) reject = (strcmp(packetInfo.ipi_ifname, intf->intfName) != 0);
else if (packetInfo.ipi_ifindex != -1) reject = (packetInfo.ipi_ifindex != intf->index);
if (reject)
{
verbosedebugf("SocketDataReady ignored a packet from %#a to %#a on interface %s/%d expecting %#a/%s/%d/%d",
&senderAddr, &destAddr, packetInfo.ipi_ifname, packetInfo.ipi_ifindex,
&intf->coreIntf.ip, intf->intfName, intf->index, skt);
packetLen = -1;
num_pkts_rejected++;
if (num_pkts_rejected > (num_pkts_accepted + 1) * (num_registered_interfaces + 1) * 2)
{
fprintf(stderr,
"*** WARNING: Received %d packets; Accepted %d packets; Rejected %d packets because of interface mismatch\n",
num_pkts_accepted + num_pkts_rejected, num_pkts_accepted, num_pkts_rejected);
num_pkts_accepted = 0;
num_pkts_rejected = 0;
}
}
else
{
verbosedebugf("SocketDataReady got a packet from %#a to %#a on interface %#a/%s/%d/%d",
&senderAddr, &destAddr, &intf->coreIntf.ip, intf->intfName, intf->index, skt);
num_pkts_accepted++;
}
}
}
if (packetLen >= 0)
mDNSCoreReceive(m, &packet, (mDNSu8 *)&packet + packetLen,
&senderAddr, senderPort, &destAddr, MulticastDNSPort, InterfaceID);
}
mDNSexport TCPSocket *mDNSPlatformTCPSocket(TCPSocketFlags flags, mDNSIPPort * port, mDNSBool useBackgroundTrafficClass)
{
(void)flags; // Unused
(void)port; // Unused
(void)useBackgroundTrafficClass; // Unused
return NULL;
}
mDNSexport TCPSocket *mDNSPlatformTCPAccept(TCPSocketFlags flags, int sd)
{
(void)flags; // Unused
(void)sd; // Unused
return NULL;
}
mDNSexport int mDNSPlatformTCPGetFD(TCPSocket *sock)
{
(void)sock; // Unused
return -1;
}
mDNSexport mStatus mDNSPlatformTCPConnect(TCPSocket *sock, const mDNSAddr *dst, mDNSOpaque16 dstport, domainname *hostname, mDNSInterfaceID InterfaceID,
TCPConnectionCallback callback, void *context)
{
(void)sock; // Unused
(void)dst; // Unused
(void)dstport; // Unused
(void)hostname; // Unused
(void)InterfaceID; // Unused
(void)callback; // Unused
(void)context; // Unused
return(mStatus_UnsupportedErr);
}
mDNSexport void mDNSPlatformTCPCloseConnection(TCPSocket *sock)
{
(void)sock; // Unused
}
mDNSexport long mDNSPlatformReadTCP(TCPSocket *sock, void *buf, unsigned long buflen, mDNSBool * closed)
{
(void)sock; // Unused
(void)buf; // Unused
(void)buflen; // Unused
(void)closed; // Unused
return 0;
}
mDNSexport long mDNSPlatformWriteTCP(TCPSocket *sock, const char *msg, unsigned long len)
{
(void)sock; // Unused
(void)msg; // Unused
(void)len; // Unused
return 0;
}
mDNSexport UDPSocket *mDNSPlatformUDPSocket(mDNSIPPort port)
{
(void)port; // Unused
return NULL;
}
mDNSexport void mDNSPlatformUDPClose(UDPSocket *sock)
{
(void)sock; // Unused
}
mDNSexport void mDNSPlatformUpdateProxyList(const mDNSInterfaceID InterfaceID)
{
(void)InterfaceID; // Unused
}
mDNSexport void mDNSPlatformSendRawPacket(const void *const msg, const mDNSu8 *const end, mDNSInterfaceID InterfaceID)
{
(void)msg; // Unused
(void)end; // Unused
(void)InterfaceID; // Unused
}
mDNSexport void mDNSPlatformSetLocalAddressCacheEntry(const mDNSAddr *const tpa, const mDNSEthAddr *const tha, mDNSInterfaceID InterfaceID)
{
(void)tpa; // Unused
(void)tha; // Unused
(void)InterfaceID; // Unused
}
mDNSexport mStatus mDNSPlatformTLSSetupCerts(void)
{
return(mStatus_UnsupportedErr);
}
mDNSexport void mDNSPlatformTLSTearDownCerts(void)
{
}
mDNSexport void mDNSPlatformSetAllowSleep(mDNSBool allowSleep, const char *reason)
{
(void) allowSleep;
(void) reason;
}
#if COMPILER_LIKES_PRAGMA_MARK
#pragma mark -
#pragma mark - /etc/hosts support
#endif
mDNSexport void FreeEtcHosts(mDNS *const m, AuthRecord *const rr, mStatus result)
{
(void)m; // unused
(void)rr;
(void)result;
}
#if COMPILER_LIKES_PRAGMA_MARK
#pragma mark ***** DDNS Config Platform Functions
#endif
mDNSexport mDNSBool mDNSPlatformSetDNSConfig(mDNSBool setservers, mDNSBool setsearch, domainname *const fqdn, DNameListElem **RegDomains,
DNameListElem **BrowseDomains, mDNSBool ackConfig)
{
(void) setservers;
(void) fqdn;
(void) setsearch;
(void) RegDomains;
(void) BrowseDomains;
(void) ackConfig;
return mDNStrue;
}
mDNSexport mStatus mDNSPlatformGetPrimaryInterface(mDNSAddr * v4, mDNSAddr * v6, mDNSAddr * router)
{
(void) v4;
(void) v6;
(void) router;
return mStatus_UnsupportedErr;
}
mDNSexport void mDNSPlatformDynDNSHostNameStatusChanged(const domainname *const dname, const mStatus status)
{
(void) dname;
(void) status;
}
#if COMPILER_LIKES_PRAGMA_MARK
#pragma mark ***** Init and Term
#endif
// This gets the current hostname, truncating it at the first dot if necessary
mDNSlocal void GetUserSpecifiedRFC1034ComputerName(domainlabel *const namelabel)
{
int len = 0;
gethostname((char *)(&namelabel->c[1]), MAX_DOMAIN_LABEL);
while (len < MAX_DOMAIN_LABEL && namelabel->c[len+1] && namelabel->c[len+1] != '.') len++;
namelabel->c[0] = len;
}
// On OS X this gets the text of the field labelled "Computer Name" in the Sharing Prefs Control Panel
// Other platforms can either get the information from the appropriate place,
// or they can alternatively just require all registering services to provide an explicit name
mDNSlocal void GetUserSpecifiedFriendlyComputerName(domainlabel *const namelabel)
{
// On Unix we have no better name than the host name, so we just use that.
GetUserSpecifiedRFC1034ComputerName(namelabel);
}
mDNSexport int ParseDNSServers(mDNS *m, const char *filePath)
{
char line[256];
char nameserver[16];
char keyword[11];
int numOfServers = 0;
FILE *fp = fopen(filePath, "r");
if (fp == NULL) return -1;
while (fgets(line,sizeof(line),fp))
{
struct in_addr ina;
line[255]='\0'; // just to be safe
if (sscanf(line,"%10s %15s", keyword, nameserver) != 2) continue; // it will skip whitespaces
if (strncasecmp(keyword,"nameserver",10)) continue;
if (inet_aton(nameserver, (struct in_addr *)&ina) != 0)
{
mDNSAddr DNSAddr;
DNSAddr.type = mDNSAddrType_IPv4;
DNSAddr.ip.v4.NotAnInteger = ina.s_addr;
mDNS_AddDNSServer(m, NULL, mDNSInterface_Any, 0, &DNSAddr, UnicastDNSPort, kScopeNone, 0, mDNSfalse, mDNSfalse, 0, mDNStrue, mDNStrue, mDNSfalse);
numOfServers++;
}
}
fclose(fp);
return (numOfServers > 0) ? 0 : -1;
}
// Searches the interface list looking for the named interface.
// Returns a pointer to if it found, or NULL otherwise.
mDNSlocal PosixNetworkInterface *SearchForInterfaceByName(mDNS *const m, const char *intfName)
{
PosixNetworkInterface *intf;
assert(m != NULL);
assert(intfName != NULL);
intf = (PosixNetworkInterface*)(m->HostInterfaces);
while ((intf != NULL) && (strcmp(intf->intfName, intfName) != 0))
intf = (PosixNetworkInterface *)(intf->coreIntf.next);
return intf;
}
mDNSexport mDNSInterfaceID mDNSPlatformInterfaceIDfromInterfaceIndex(mDNS *const m, mDNSu32 index)
{
PosixNetworkInterface *intf;
assert(m != NULL);
if (index == kDNSServiceInterfaceIndexLocalOnly) return(mDNSInterface_LocalOnly);
if (index == kDNSServiceInterfaceIndexP2P ) return(mDNSInterface_P2P);
if (index == kDNSServiceInterfaceIndexAny ) return(mDNSInterface_Any);
intf = (PosixNetworkInterface*)(m->HostInterfaces);
while ((intf != NULL) && (mDNSu32) intf->index != index)
intf = (PosixNetworkInterface *)(intf->coreIntf.next);
return (mDNSInterfaceID) intf;
}
mDNSexport mDNSu32 mDNSPlatformInterfaceIndexfromInterfaceID(mDNS *const m, mDNSInterfaceID id, mDNSBool suppressNetworkChange)
{
PosixNetworkInterface *intf;
(void) suppressNetworkChange; // Unused
assert(m != NULL);
if (id == mDNSInterface_LocalOnly) return(kDNSServiceInterfaceIndexLocalOnly);
if (id == mDNSInterface_P2P ) return(kDNSServiceInterfaceIndexP2P);
if (id == mDNSInterface_Any ) return(kDNSServiceInterfaceIndexAny);
intf = (PosixNetworkInterface*)(m->HostInterfaces);
while ((intf != NULL) && (mDNSInterfaceID) intf != id)
intf = (PosixNetworkInterface *)(intf->coreIntf.next);
if (intf) return intf->index;
// If we didn't find the interface, check the RecentInterfaces list as well
intf = gRecentInterfaces;
while ((intf != NULL) && (mDNSInterfaceID) intf != id)
intf = (PosixNetworkInterface *)(intf->coreIntf.next);
return intf ? intf->index : 0;
}
// Frees the specified PosixNetworkInterface structure. The underlying
// interface must have already been deregistered with the mDNS core.
mDNSlocal void FreePosixNetworkInterface(PosixNetworkInterface *intf)
{
int rv;
assert(intf != NULL);
if (intf->intfName != NULL) free((void *)intf->intfName);
if (intf->multicastSocket4 != -1)
{
rv = close(intf->multicastSocket4);
assert(rv == 0);
}
#if HAVE_IPV6
if (intf->multicastSocket6 != -1)
{
rv = close(intf->multicastSocket6);
assert(rv == 0);
}
#endif
// Move interface to the RecentInterfaces list for a minute
intf->LastSeen = mDNSPlatformUTC();
intf->coreIntf.next = &gRecentInterfaces->coreIntf;
gRecentInterfaces = intf;
}
// Grab the first interface, deregister it, free it, and repeat until done.
mDNSlocal void ClearInterfaceList(mDNS *const m)
{
assert(m != NULL);
while (m->HostInterfaces)
{
PosixNetworkInterface *intf = (PosixNetworkInterface*)(m->HostInterfaces);
mDNS_DeregisterInterface(m, &intf->coreIntf, NormalActivation);
if (gMDNSPlatformPosixVerboseLevel > 0) fprintf(stderr, "Deregistered interface %s\n", intf->intfName);
FreePosixNetworkInterface(intf);
}
num_registered_interfaces = 0;
num_pkts_accepted = 0;
num_pkts_rejected = 0;
}
// Sets up a send/receive socket.
// If mDNSIPPort port is non-zero, then it's a multicast socket on the specified interface
// If mDNSIPPort port is zero, then it's a randomly assigned port number, used for sending unicast queries
mDNSlocal int SetupSocket(struct sockaddr *intfAddr, mDNSIPPort port, int interfaceIndex, int *sktPtr)
{
int err = 0;
static const int kOn = 1;
static const int kIntTwoFiveFive = 255;
static const unsigned char kByteTwoFiveFive = 255;
const mDNSBool JoinMulticastGroup = (port.NotAnInteger != 0);
(void) interfaceIndex; // This parameter unused on plaforms that don't have IPv6
assert(intfAddr != NULL);
assert(sktPtr != NULL);
assert(*sktPtr == -1);
// Open the socket...
if (intfAddr->sa_family == AF_INET) *sktPtr = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
#if HAVE_IPV6
else if (intfAddr->sa_family == AF_INET6) *sktPtr = socket(PF_INET6, SOCK_DGRAM, IPPROTO_UDP);
#endif
else return EINVAL;
if (*sktPtr < 0) { err = errno; perror((intfAddr->sa_family == AF_INET) ? "socket AF_INET" : "socket AF_INET6"); }
// ... with a shared UDP port, if it's for multicast receiving
if (err == 0 && port.NotAnInteger)
{
// <rdar://problem/20946253>
// We test for SO_REUSEADDR first, as suggested by Jonny Törnbom from Axis Communications
// Linux kernel versions 3.9 introduces support for socket option
// SO_REUSEPORT, however this is not implemented the same as on *BSD
// systems. Linux version implements a "port hijacking" prevention
// mechanism, limiting processes wanting to bind to an already existing
// addr:port to have the same effective UID as the first who bound it. What
// this meant for us was that the daemon ran as one user and when for
// instance mDNSClientPosix was executed by another user, it wasn't allowed
// to bind to the socket. Our suggestion was to switch the order in which
// SO_REUSEPORT and SO_REUSEADDR was tested so that SO_REUSEADDR stays on
// top and SO_REUSEPORT to be used only if SO_REUSEADDR doesn't exist.
#if defined(SO_REUSEADDR) && !defined(__MAC_OS_X_VERSION_MIN_REQUIRED)
err = setsockopt(*sktPtr, SOL_SOCKET, SO_REUSEADDR, &kOn, sizeof(kOn));
#elif defined(SO_REUSEPORT)
err = setsockopt(*sktPtr, SOL_SOCKET, SO_REUSEPORT, &kOn, sizeof(kOn));
#else
#error This platform has no way to avoid address busy errors on multicast.
#endif
if (err < 0) { err = errno; perror("setsockopt - SO_REUSExxxx"); }
// Enable inbound packets on IFEF_AWDL interface.
// Only done for multicast sockets, since we don't expect unicast socket operations
// on the IFEF_AWDL interface. Operation is a no-op for other interface types.
#ifndef SO_RECV_ANYIF
#define SO_RECV_ANYIF 0x1104 /* unrestricted inbound processing */
#endif
if (setsockopt(*sktPtr, SOL_SOCKET, SO_RECV_ANYIF, &kOn, sizeof(kOn)) < 0) perror("setsockopt - SO_RECV_ANYIF");
}
// We want to receive destination addresses and interface identifiers.
if (intfAddr->sa_family == AF_INET)
{
struct ip_mreq imr;
struct sockaddr_in bindAddr;
if (err == 0)
{
#if defined(IP_PKTINFO) // Linux
err = setsockopt(*sktPtr, IPPROTO_IP, IP_PKTINFO, &kOn, sizeof(kOn));
if (err < 0) { err = errno; perror("setsockopt - IP_PKTINFO"); }
#elif defined(IP_RECVDSTADDR) || defined(IP_RECVIF) // BSD and Solaris
#if defined(IP_RECVDSTADDR)
err = setsockopt(*sktPtr, IPPROTO_IP, IP_RECVDSTADDR, &kOn, sizeof(kOn));
if (err < 0) { err = errno; perror("setsockopt - IP_RECVDSTADDR"); }
#endif
#if defined(IP_RECVIF)
if (err == 0)
{
err = setsockopt(*sktPtr, IPPROTO_IP, IP_RECVIF, &kOn, sizeof(kOn));
if (err < 0) { err = errno; perror("setsockopt - IP_RECVIF"); }
}
#endif
#else
#warning This platform has no way to get the destination interface information -- will only work for single-homed hosts
#endif
}
#if defined(IP_RECVTTL) // Linux
if (err == 0)
{
setsockopt(*sktPtr, IPPROTO_IP, IP_RECVTTL, &kOn, sizeof(kOn));
// We no longer depend on being able to get the received TTL, so don't worry if the option fails
}
#endif
// Add multicast group membership on this interface
if (err == 0 && JoinMulticastGroup)
{
imr.imr_multiaddr.s_addr = AllDNSLinkGroup_v4.ip.v4.NotAnInteger;
imr.imr_interface = ((struct sockaddr_in*)intfAddr)->sin_addr;
err = setsockopt(*sktPtr, IPPROTO_IP, IP_ADD_MEMBERSHIP, &imr, sizeof(imr));
if (err < 0) { err = errno; perror("setsockopt - IP_ADD_MEMBERSHIP"); }
}
// Specify outgoing interface too
if (err == 0 && JoinMulticastGroup)
{
err = setsockopt(*sktPtr, IPPROTO_IP, IP_MULTICAST_IF, &((struct sockaddr_in*)intfAddr)->sin_addr, sizeof(struct in_addr));
if (err < 0) { err = errno; perror("setsockopt - IP_MULTICAST_IF"); }
}
// Per the mDNS spec, send unicast packets with TTL 255
if (err == 0)
{
err = setsockopt(*sktPtr, IPPROTO_IP, IP_TTL, &kIntTwoFiveFive, sizeof(kIntTwoFiveFive));
if (err < 0) { err = errno; perror("setsockopt - IP_TTL"); }
}
// and multicast packets with TTL 255 too
// There's some debate as to whether IP_MULTICAST_TTL is an int or a byte so we just try both.
if (err == 0)
{
err = setsockopt(*sktPtr, IPPROTO_IP, IP_MULTICAST_TTL, &kByteTwoFiveFive, sizeof(kByteTwoFiveFive));
if (err < 0 && errno == EINVAL)
err = setsockopt(*sktPtr, IPPROTO_IP, IP_MULTICAST_TTL, &kIntTwoFiveFive, sizeof(kIntTwoFiveFive));
if (err < 0) { err = errno; perror("setsockopt - IP_MULTICAST_TTL"); }
}
// And start listening for packets
if (err == 0)
{
bindAddr.sin_family = AF_INET;
bindAddr.sin_port = port.NotAnInteger;
bindAddr.sin_addr.s_addr = INADDR_ANY; // Want to receive multicasts AND unicasts on this socket
err = bind(*sktPtr, (struct sockaddr *) &bindAddr, sizeof(bindAddr));
if (err < 0) { err = errno; perror("bind"); fflush(stderr); }
}
} // endif (intfAddr->sa_family == AF_INET)
#if HAVE_IPV6
else if (intfAddr->sa_family == AF_INET6)
{
struct ipv6_mreq imr6;
struct sockaddr_in6 bindAddr6;
#if defined(IPV6_PKTINFO)
if (err == 0)
{
err = setsockopt(*sktPtr, IPPROTO_IPV6, IPV6_2292_PKTINFO, &kOn, sizeof(kOn));
if (err < 0) { err = errno; perror("setsockopt - IPV6_PKTINFO"); }
}
#else
#warning This platform has no way to get the destination interface information for IPv6 -- will only work for single-homed hosts
#endif
#if defined(IPV6_HOPLIMIT)
if (err == 0)
{
err = setsockopt(*sktPtr, IPPROTO_IPV6, IPV6_2292_HOPLIMIT, &kOn, sizeof(kOn));
if (err < 0) { err = errno; perror("setsockopt - IPV6_HOPLIMIT"); }
}
#endif
// Add multicast group membership on this interface
if (err == 0 && JoinMulticastGroup)
{
imr6.ipv6mr_multiaddr = *(const struct in6_addr*)&AllDNSLinkGroup_v6.ip.v6;
imr6.ipv6mr_interface = interfaceIndex;
//LogMsg("Joining %.16a on %d", &imr6.ipv6mr_multiaddr, imr6.ipv6mr_interface);
err = setsockopt(*sktPtr, IPPROTO_IPV6, IPV6_JOIN_GROUP, &imr6, sizeof(imr6));
if (err < 0)
{
err = errno;
verbosedebugf("IPV6_JOIN_GROUP %.16a on %d failed.\n", &imr6.ipv6mr_multiaddr, imr6.ipv6mr_interface);
perror("setsockopt - IPV6_JOIN_GROUP");
}
}
// Specify outgoing interface too
if (err == 0 && JoinMulticastGroup)
{
u_int multicast_if = interfaceIndex;
err = setsockopt(*sktPtr, IPPROTO_IPV6, IPV6_MULTICAST_IF, &multicast_if, sizeof(multicast_if));
if (err < 0) { err = errno; perror("setsockopt - IPV6_MULTICAST_IF"); }
}
// We want to receive only IPv6 packets on this socket.
// Without this option, we may get IPv4 addresses as mapped addresses.
if (err == 0)
{
err = setsockopt(*sktPtr, IPPROTO_IPV6, IPV6_V6ONLY, &kOn, sizeof(kOn));
if (err < 0) { err = errno; perror("setsockopt - IPV6_V6ONLY"); }
}
// Per the mDNS spec, send unicast packets with TTL 255
if (err == 0)
{
err = setsockopt(*sktPtr, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &kIntTwoFiveFive, sizeof(kIntTwoFiveFive));
if (err < 0) { err = errno; perror("setsockopt - IPV6_UNICAST_HOPS"); }
}
// and multicast packets with TTL 255 too
// There's some debate as to whether IPV6_MULTICAST_HOPS is an int or a byte so we just try both.
if (err == 0)
{
err = setsockopt(*sktPtr, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &kByteTwoFiveFive, sizeof(kByteTwoFiveFive));
if (err < 0 && errno == EINVAL)
err = setsockopt(*sktPtr, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &kIntTwoFiveFive, sizeof(kIntTwoFiveFive));
if (err < 0) { err = errno; perror("setsockopt - IPV6_MULTICAST_HOPS"); }
}
// And start listening for packets
if (err == 0)
{
mDNSPlatformMemZero(&bindAddr6, sizeof(bindAddr6));
#ifndef NOT_HAVE_SA_LEN
bindAddr6.sin6_len = sizeof(bindAddr6);
#endif
bindAddr6.sin6_family = AF_INET6;
bindAddr6.sin6_port = port.NotAnInteger;
bindAddr6.sin6_flowinfo = 0;
bindAddr6.sin6_addr = in6addr_any; // Want to receive multicasts AND unicasts on this socket
bindAddr6.sin6_scope_id = 0;
err = bind(*sktPtr, (struct sockaddr *) &bindAddr6, sizeof(bindAddr6));
if (err < 0) { err = errno; perror("bind"); fflush(stderr); }
}
} // endif (intfAddr->sa_family == AF_INET6)
#endif
// Set the socket to non-blocking.
if (err == 0)
{
err = fcntl(*sktPtr, F_GETFL, 0);
if (err < 0) err = errno;
else
{
err = fcntl(*sktPtr, F_SETFL, err | O_NONBLOCK);
if (err < 0) err = errno;
}
}
// Clean up
if (err != 0 && *sktPtr != -1)
{
int rv;
rv = close(*sktPtr);
assert(rv == 0);
*sktPtr = -1;
}
assert((err == 0) == (*sktPtr != -1));
return err;
}
// Creates a PosixNetworkInterface for the interface whose IP address is
// intfAddr and whose name is intfName and registers it with mDNS core.
mDNSlocal int SetupOneInterface(mDNS *const m, struct sockaddr *intfAddr, struct sockaddr *intfMask, const char *intfName, int intfIndex)
{
int err = 0;
PosixNetworkInterface *intf;
PosixNetworkInterface *alias = NULL;
assert(m != NULL);
assert(intfAddr != NULL);
assert(intfName != NULL);
assert(intfMask != NULL);
// Allocate the interface structure itself.
intf = (PosixNetworkInterface*)calloc(1, sizeof(*intf));
if (intf == NULL) { assert(0); err = ENOMEM; }
// And make a copy of the intfName.
if (err == 0)
{
intf->intfName = strdup(intfName);
if (intf->intfName == NULL) { assert(0); err = ENOMEM; }
}
if (err == 0)
{
// Set up the fields required by the mDNS core.
SockAddrTomDNSAddr(intfAddr, &intf->coreIntf.ip, NULL);
SockAddrTomDNSAddr(intfMask, &intf->coreIntf.mask, NULL);
//LogMsg("SetupOneInterface: %#a %#a", &intf->coreIntf.ip, &intf->coreIntf.mask);
strncpy(intf->coreIntf.ifname, intfName, sizeof(intf->coreIntf.ifname));
intf->coreIntf.ifname[sizeof(intf->coreIntf.ifname)-1] = 0;
intf->coreIntf.Advertise = m->AdvertiseLocalAddresses;
intf->coreIntf.McastTxRx = mDNStrue;
// Set up the extra fields in PosixNetworkInterface.
assert(intf->intfName != NULL); // intf->intfName already set up above
intf->index = intfIndex;
intf->multicastSocket4 = -1;
#if HAVE_IPV6
intf->multicastSocket6 = -1;
#endif
alias = SearchForInterfaceByName(m, intf->intfName);
if (alias == NULL) alias = intf;
intf->coreIntf.InterfaceID = (mDNSInterfaceID)alias;
if (alias != intf)
debugf("SetupOneInterface: %s %#a is an alias of %#a", intfName, &intf->coreIntf.ip, &alias->coreIntf.ip);
}
// Set up the multicast socket
if (err == 0)
{
if (alias->multicastSocket4 == -1 && intfAddr->sa_family == AF_INET)
err = SetupSocket(intfAddr, MulticastDNSPort, intf->index, &alias->multicastSocket4);
#if HAVE_IPV6
else if (alias->multicastSocket6 == -1 && intfAddr->sa_family == AF_INET6)
err = SetupSocket(intfAddr, MulticastDNSPort, intf->index, &alias->multicastSocket6);
#endif
}
// If interface is a direct link, address record will be marked as kDNSRecordTypeKnownUnique
// and skip the probe phase of the probe/announce packet sequence.
intf->coreIntf.DirectLink = mDNSfalse;
#ifdef DIRECTLINK_INTERFACE_NAME
if (strcmp(intfName, STRINGIFY(DIRECTLINK_INTERFACE_NAME)) == 0)
intf->coreIntf.DirectLink = mDNStrue;
#endif
intf->coreIntf.SupportsUnicastMDNSResponse = mDNStrue;
// The interface is all ready to go, let's register it with the mDNS core.
if (err == 0)
err = mDNS_RegisterInterface(m, &intf->coreIntf, NormalActivation);
// Clean up.
if (err == 0)
{
num_registered_interfaces++;
debugf("SetupOneInterface: %s %#a Registered", intf->intfName, &intf->coreIntf.ip);
if (gMDNSPlatformPosixVerboseLevel > 0)
fprintf(stderr, "Registered interface %s\n", intf->intfName);
}
else
{
// Use intfName instead of intf->intfName in the next line to avoid dereferencing NULL.
debugf("SetupOneInterface: %s %#a failed to register %d", intfName, &intf->coreIntf.ip, err);
if (intf) { FreePosixNetworkInterface(intf); intf = NULL; }
}
assert((err == 0) == (intf != NULL));
return err;
}
// Call get_ifi_info() to obtain a list of active interfaces and call SetupOneInterface() on each one.
mDNSlocal int SetupInterfaceList(mDNS *const m)
{
mDNSBool foundav4 = mDNSfalse;
int err = 0;
struct ifi_info *intfList = get_ifi_info(AF_INET, mDNStrue);
struct ifi_info *firstLoopback = NULL;
assert(m != NULL);
debugf("SetupInterfaceList");
if (intfList == NULL) err = ENOENT;
#if HAVE_IPV6
if (err == 0) /* Link the IPv6 list to the end of the IPv4 list */
{
struct ifi_info **p = &intfList;
while (*p) p = &(*p)->ifi_next;
*p = get_ifi_info(AF_INET6, mDNStrue);
}
#endif
if (err == 0)
{
struct ifi_info *i = intfList;
while (i)
{
if ( ((i->ifi_addr->sa_family == AF_INET)
#if HAVE_IPV6
|| (i->ifi_addr->sa_family == AF_INET6)
#endif
) && (i->ifi_flags & IFF_UP) && !(i->ifi_flags & IFF_POINTOPOINT))
{
if (i->ifi_flags & IFF_LOOPBACK)
{
if (firstLoopback == NULL)
firstLoopback = i;
}
else
{
if (SetupOneInterface(m, i->ifi_addr, i->ifi_netmask, i->ifi_name, i->ifi_index) == 0)
if (i->ifi_addr->sa_family == AF_INET)
foundav4 = mDNStrue;
}
}
i = i->ifi_next;
}
// If we found no normal interfaces but we did find a loopback interface, register the
// loopback interface. This allows self-discovery if no interfaces are configured.
// Temporary workaround: Multicast loopback on IPv6 interfaces appears not to work.
// In the interim, we skip loopback interface only if we found at least one v4 interface to use
// if ((m->HostInterfaces == NULL) && (firstLoopback != NULL))
if (!foundav4 && firstLoopback)
(void) SetupOneInterface(m, firstLoopback->ifi_addr, firstLoopback->ifi_netmask, firstLoopback->ifi_name, firstLoopback->ifi_index);
}
// Clean up.
if (intfList != NULL) free_ifi_info(intfList);
// Clean up any interfaces that have been hanging around on the RecentInterfaces list for more than a minute
PosixNetworkInterface **ri = &gRecentInterfaces;
const mDNSs32 utc = mDNSPlatformUTC();
while (*ri)
{
PosixNetworkInterface *pi = *ri;
if (utc - pi->LastSeen < 60) ri = (PosixNetworkInterface **)&pi->coreIntf.next;
else { *ri = (PosixNetworkInterface *)pi->coreIntf.next; free(pi); }
}
return err;
}
#if USES_NETLINK
// See <http://www.faqs.org/rfcs/rfc3549.html> for a description of NetLink
// Open a socket that will receive interface change notifications
mDNSlocal mStatus OpenIfNotifySocket(int *pFD)
{
mStatus err = mStatus_NoError;
struct sockaddr_nl snl;
int sock;
int ret;
sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (sock < 0)
return errno;
// Configure read to be non-blocking because inbound msg size is not known in advance
(void) fcntl(sock, F_SETFL, O_NONBLOCK);
/* Subscribe the socket to Link & IP addr notifications. */
mDNSPlatformMemZero(&snl, sizeof snl);
snl.nl_family = AF_NETLINK;
snl.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR;
ret = bind(sock, (struct sockaddr *) &snl, sizeof snl);
if (0 == ret)
*pFD = sock;
else
err = errno;
return err;
}
#if MDNS_DEBUGMSGS
mDNSlocal void PrintNetLinkMsg(const struct nlmsghdr *pNLMsg)
{
const char *kNLMsgTypes[] = { "", "NLMSG_NOOP", "NLMSG_ERROR", "NLMSG_DONE", "NLMSG_OVERRUN" };
const char *kNLRtMsgTypes[] = { "RTM_NEWLINK", "RTM_DELLINK", "RTM_GETLINK", "RTM_NEWADDR", "RTM_DELADDR", "RTM_GETADDR" };
printf("nlmsghdr len=%d, type=%s, flags=0x%x\n", pNLMsg->nlmsg_len,
pNLMsg->nlmsg_type < RTM_BASE ? kNLMsgTypes[pNLMsg->nlmsg_type] : kNLRtMsgTypes[pNLMsg->nlmsg_type - RTM_BASE],
pNLMsg->nlmsg_flags);
if (RTM_NEWLINK <= pNLMsg->nlmsg_type && pNLMsg->nlmsg_type <= RTM_GETLINK)
{
struct ifinfomsg *pIfInfo = (struct ifinfomsg*) NLMSG_DATA(pNLMsg);
printf("ifinfomsg family=%d, type=%d, index=%d, flags=0x%x, change=0x%x\n", pIfInfo->ifi_family,
pIfInfo->ifi_type, pIfInfo->ifi_index, pIfInfo->ifi_flags, pIfInfo->ifi_change);
}
else if (RTM_NEWADDR <= pNLMsg->nlmsg_type && pNLMsg->nlmsg_type <= RTM_GETADDR)
{
struct ifaddrmsg *pIfAddr = (struct ifaddrmsg*) NLMSG_DATA(pNLMsg);
printf("ifaddrmsg family=%d, index=%d, flags=0x%x\n", pIfAddr->ifa_family,
pIfAddr->ifa_index, pIfAddr->ifa_flags);
}
printf("\n");
}
#endif
mDNSlocal mDNSu32 ProcessRoutingNotification(int sd)
// Read through the messages on sd and if any indicate that any interface records should
// be torn down and rebuilt, return affected indices as a bitmask. Otherwise return 0.
{
ssize_t readCount;
char buff[4096];
struct nlmsghdr *pNLMsg = (struct nlmsghdr*) buff;
mDNSu32 result = 0;
// The structure here is more complex than it really ought to be because,
// unfortunately, there's no good way to size a buffer in advance large
// enough to hold all pending data and so avoid message fragmentation.
// (Note that FIONREAD is not supported on AF_NETLINK.)
readCount = read(sd, buff, sizeof buff);
while (1)
{
// Make sure we've got an entire nlmsghdr in the buffer, and payload, too.
// If not, discard already-processed messages in buffer and read more data.
if (((char*) &pNLMsg[1] > (buff + readCount)) || // i.e. *pNLMsg extends off end of buffer
((char*) pNLMsg + pNLMsg->nlmsg_len > (buff + readCount)))
{
if (buff < (char*) pNLMsg) // we have space to shuffle
{
// discard processed data
readCount -= ((char*) pNLMsg - buff);
memmove(buff, pNLMsg, readCount);
pNLMsg = (struct nlmsghdr*) buff;
// read more data
readCount += read(sd, buff + readCount, sizeof buff - readCount);
continue; // spin around and revalidate with new readCount
}
else
break; // Otherwise message does not fit in buffer
}
#if MDNS_DEBUGMSGS
PrintNetLinkMsg(pNLMsg);
#endif
// Process the NetLink message
if (pNLMsg->nlmsg_type == RTM_GETLINK || pNLMsg->nlmsg_type == RTM_NEWLINK)
result |= 1 << ((struct ifinfomsg*) NLMSG_DATA(pNLMsg))->ifi_index;
else if (pNLMsg->nlmsg_type == RTM_DELADDR || pNLMsg->nlmsg_type == RTM_NEWADDR)
result |= 1 << ((struct ifaddrmsg*) NLMSG_DATA(pNLMsg))->ifa_index;
// Advance pNLMsg to the next message in the buffer
if ((pNLMsg->nlmsg_flags & NLM_F_MULTI) != 0 && pNLMsg->nlmsg_type != NLMSG_DONE)
{
ssize_t len = readCount - ((char*)pNLMsg - buff);
pNLMsg = NLMSG_NEXT(pNLMsg, len);
}
else
break; // all done!
}
return result;
}
#else // USES_NETLINK
// Open a socket that will receive interface change notifications
mDNSlocal mStatus OpenIfNotifySocket(int *pFD)
{
*pFD = socket(AF_ROUTE, SOCK_RAW, 0);
if (*pFD < 0)
return mStatus_UnknownErr;
// Configure read to be non-blocking because inbound msg size is not known in advance
(void) fcntl(*pFD, F_SETFL, O_NONBLOCK);
return mStatus_NoError;
}
#if MDNS_DEBUGMSGS
mDNSlocal void PrintRoutingSocketMsg(const struct ifa_msghdr *pRSMsg)
{
const char *kRSMsgTypes[] = { "", "RTM_ADD", "RTM_DELETE", "RTM_CHANGE", "RTM_GET", "RTM_LOSING",
"RTM_REDIRECT", "RTM_MISS", "RTM_LOCK", "RTM_OLDADD", "RTM_OLDDEL", "RTM_RESOLVE",
"RTM_NEWADDR", "RTM_DELADDR", "RTM_IFINFO", "RTM_NEWMADDR", "RTM_DELMADDR" };
int index = pRSMsg->ifam_type == RTM_IFINFO ? ((struct if_msghdr*) pRSMsg)->ifm_index : pRSMsg->ifam_index;
printf("ifa_msghdr len=%d, type=%s, index=%d\n", pRSMsg->ifam_msglen, kRSMsgTypes[pRSMsg->ifam_type], index);
}
#endif
mDNSlocal mDNSu32 ProcessRoutingNotification(int sd)
// Read through the messages on sd and if any indicate that any interface records should
// be torn down and rebuilt, return affected indices as a bitmask. Otherwise return 0.
{
ssize_t readCount;
char buff[4096];
struct ifa_msghdr *pRSMsg = (struct ifa_msghdr*) buff;
mDNSu32 result = 0;
readCount = read(sd, buff, sizeof buff);
if (readCount < (ssize_t) sizeof(struct ifa_msghdr))
return mStatus_UnsupportedErr; // cannot decipher message
#if MDNS_DEBUGMSGS
PrintRoutingSocketMsg(pRSMsg);
#endif
// Process the message
if (pRSMsg->ifam_type == RTM_NEWADDR || pRSMsg->ifam_type == RTM_DELADDR ||
pRSMsg->ifam_type == RTM_IFINFO)
{
if (pRSMsg->ifam_type == RTM_IFINFO)
result |= 1 << ((struct if_msghdr*) pRSMsg)->ifm_index;
else
result |= 1 << pRSMsg->ifam_index;
}
return result;
}
#endif // USES_NETLINK
// Called when data appears on interface change notification socket
mDNSlocal void InterfaceChangeCallback(int fd, short filter, void *context)
{
IfChangeRec *pChgRec = (IfChangeRec*) context;
fd_set readFDs;
mDNSu32 changedInterfaces = 0;
struct timeval zeroTimeout = { 0, 0 };
(void)fd; // Unused
(void)filter; // Unused
FD_ZERO(&readFDs);
FD_SET(pChgRec->NotifySD, &readFDs);
do
{
changedInterfaces |= ProcessRoutingNotification(pChgRec->NotifySD);
}
while (0 < select(pChgRec->NotifySD + 1, &readFDs, (fd_set*) NULL, (fd_set*) NULL, &zeroTimeout));
// Currently we rebuild the entire interface list whenever any interface change is
// detected. If this ever proves to be a performance issue in a multi-homed
// configuration, more care should be paid to changedInterfaces.
if (changedInterfaces)
mDNSPlatformPosixRefreshInterfaceList(pChgRec->mDNS);
}
// Register with either a Routing Socket or RtNetLink to listen for interface changes.
mDNSlocal mStatus WatchForInterfaceChange(mDNS *const m)
{
mStatus err;
IfChangeRec *pChgRec;
pChgRec = (IfChangeRec*) mDNSPlatformMemAllocate(sizeof *pChgRec);
if (pChgRec == NULL)
return mStatus_NoMemoryErr;
pChgRec->mDNS = m;
err = OpenIfNotifySocket(&pChgRec->NotifySD);
if (err == 0)
err = mDNSPosixAddFDToEventLoop(pChgRec->NotifySD, InterfaceChangeCallback, pChgRec);
return err;
}
// Test to see if we're the first client running on UDP port 5353, by trying to bind to 5353 without using SO_REUSEPORT.
// If we fail, someone else got here first. That's not a big problem; we can share the port for multicast responses --
// we just need to be aware that we shouldn't expect to successfully receive unicast UDP responses.
mDNSlocal mDNSBool mDNSPlatformInit_CanReceiveUnicast(void)
{
int err;
int s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
struct sockaddr_in s5353;
s5353.sin_family = AF_INET;
s5353.sin_port = MulticastDNSPort.NotAnInteger;
s5353.sin_addr.s_addr = 0;
err = bind(s, (struct sockaddr *)&s5353, sizeof(s5353));
close(s);
if (err) debugf("No unicast UDP responses");
else debugf("Unicast UDP responses okay");
return(err == 0);
}
// mDNS core calls this routine to initialise the platform-specific data.
mDNSexport mStatus mDNSPlatformInit(mDNS *const m)
{
int err = 0;
struct sockaddr sa;
assert(m != NULL);
if (mDNSPlatformInit_CanReceiveUnicast()) m->CanReceiveUnicastOn5353 = mDNStrue;
// Tell mDNS core the names of this machine.
// Set up the nice label
m->nicelabel.c[0] = 0;
GetUserSpecifiedFriendlyComputerName(&m->nicelabel);
if (m->nicelabel.c[0] == 0) MakeDomainLabelFromLiteralString(&m->nicelabel, "Computer");
// Set up the RFC 1034-compliant label
m->hostlabel.c[0] = 0;
GetUserSpecifiedRFC1034ComputerName(&m->hostlabel);
if (m->hostlabel.c[0] == 0) MakeDomainLabelFromLiteralString(&m->hostlabel, "Computer");
mDNS_SetFQDN(m);
sa.sa_family = AF_INET;
m->p->unicastSocket4 = -1;
if (err == mStatus_NoError) err = SetupSocket(&sa, zeroIPPort, 0, &m->p->unicastSocket4);
#if HAVE_IPV6
sa.sa_family = AF_INET6;
m->p->unicastSocket6 = -1;
if (err == mStatus_NoError) err = SetupSocket(&sa, zeroIPPort, 0, &m->p->unicastSocket6);
#endif
// Tell mDNS core about the network interfaces on this machine.
if (err == mStatus_NoError) err = SetupInterfaceList(m);
// Tell mDNS core about DNS Servers
mDNS_Lock(m);
if (err == mStatus_NoError) ParseDNSServers(m, uDNS_SERVERS_FILE);
mDNS_Unlock(m);
if (err == mStatus_NoError)
{
err = WatchForInterfaceChange(m);
// Failure to observe interface changes is non-fatal.
if (err != mStatus_NoError)
{
fprintf(stderr, "mDNS(%d) WARNING: Unable to detect interface changes (%d).\n", getpid(), err);
err = mStatus_NoError;
}
}
// We don't do asynchronous initialization on the Posix platform, so by the time
// we get here the setup will already have succeeded or failed. If it succeeded,
// we should just call mDNSCoreInitComplete() immediately.
if (err == mStatus_NoError)
mDNSCoreInitComplete(m, mStatus_NoError);
return PosixErrorToStatus(err);
}
// mDNS core calls this routine to clean up the platform-specific data.
// In our case all we need to do is to tear down every network interface.
mDNSexport void mDNSPlatformClose(mDNS *const m)
{
int rv;
assert(m != NULL);
ClearInterfaceList(m);
if (m->p->unicastSocket4 != -1)
{
rv = close(m->p->unicastSocket4);
assert(rv == 0);
}
#if HAVE_IPV6
if (m->p->unicastSocket6 != -1)
{
rv = close(m->p->unicastSocket6);
assert(rv == 0);
}
#endif
}
// This is used internally by InterfaceChangeCallback.
// It's also exported so that the Standalone Responder (mDNSResponderPosix)
// can call it in response to a SIGHUP (mainly for debugging purposes).
mDNSexport mStatus mDNSPlatformPosixRefreshInterfaceList(mDNS *const m)
{
int err;
// This is a pretty heavyweight way to process interface changes --
// destroying the entire interface list and then making fresh one from scratch.
// We should make it like the OS X version, which leaves unchanged interfaces alone.
ClearInterfaceList(m);
err = SetupInterfaceList(m);
return PosixErrorToStatus(err);
}
#if COMPILER_LIKES_PRAGMA_MARK
#pragma mark ***** Locking
#endif
// On the Posix platform, locking is a no-op because we only ever enter
// mDNS core on the main thread.
// mDNS core calls this routine when it wants to prevent
// the platform from reentering mDNS core code.
mDNSexport void mDNSPlatformLock (const mDNS *const m)
{
(void) m; // Unused
}
// mDNS core calls this routine when it release the lock taken by
// mDNSPlatformLock and allow the platform to reenter mDNS core code.
mDNSexport void mDNSPlatformUnlock (const mDNS *const m)
{
(void) m; // Unused
}
#if COMPILER_LIKES_PRAGMA_MARK
#pragma mark ***** Strings
#endif
// mDNS core calls this routine to copy C strings.
// On the Posix platform this maps directly to the ANSI C strcpy.
mDNSexport void mDNSPlatformStrCopy(void *dst, const void *src)
{
strcpy((char *)dst, (const char *)src);
}
mDNSexport mDNSu32 mDNSPlatformStrLCopy(void *dst, const void *src, mDNSu32 len)
{
#if HAVE_STRLCPY
return ((mDNSu32)strlcpy((char *)dst, (const char *)src, len));
#else
size_t srcLen;
srcLen = strlen((const char *)src);
if (srcLen < len)
{
memcpy(dst, src, srcLen + 1);
}
else if (len > 0)
{
memcpy(dst, src, len - 1);
((char *)dst)[len - 1] = '\0';
}
return ((mDNSu32)srcLen);
#endif
}
// mDNS core calls this routine to get the length of a C string.
// On the Posix platform this maps directly to the ANSI C strlen.
mDNSexport mDNSu32 mDNSPlatformStrLen (const void *src)
{
return strlen((const char*)src);
}
// mDNS core calls this routine to copy memory.
// On the Posix platform this maps directly to the ANSI C memcpy.
mDNSexport void mDNSPlatformMemCopy(void *dst, const void *src, mDNSu32 len)
{
memcpy(dst, src, len);
}
// mDNS core calls this routine to test whether blocks of memory are byte-for-byte
// identical. On the Posix platform this is a simple wrapper around ANSI C memcmp.
mDNSexport mDNSBool mDNSPlatformMemSame(const void *dst, const void *src, mDNSu32 len)
{
return memcmp(dst, src, len) == 0;
}
// If the caller wants to know the exact return of memcmp, then use this instead
// of mDNSPlatformMemSame
mDNSexport int mDNSPlatformMemCmp(const void *dst, const void *src, mDNSu32 len)
{
return (memcmp(dst, src, len));
}
mDNSexport void mDNSPlatformQsort(void *base, int nel, int width, int (*compar)(const void *, const void *))
{
return (qsort(base, nel, width, compar));
}
// DNSSEC stub functions
mDNSexport void VerifySignature(mDNS *const m, DNSSECVerifier *dv, DNSQuestion *q)
{
(void)m;
(void)dv;
(void)q;
}
mDNSexport mDNSBool AddNSECSForCacheRecord(mDNS *const m, CacheRecord *crlist, CacheRecord *negcr, mDNSu8 rcode)
{
(void)m;
(void)crlist;
(void)negcr;
(void)rcode;
return mDNSfalse;
}
mDNSexport void BumpDNSSECStats(mDNS *const m, DNSSECStatsAction action, DNSSECStatsType type, mDNSu32 value)
{
(void)m;
(void)action;
(void)type;
(void)value;
}
// Proxy stub functions
mDNSexport mDNSu8 *DNSProxySetAttributes(DNSQuestion *q, DNSMessageHeader *h, DNSMessage *msg, mDNSu8 *ptr, mDNSu8 *limit)
{
(void) q;
(void) h;
(void) msg;
(void) ptr;
(void) limit;
return ptr;
}
mDNSexport void DNSProxyInit(mDNSu32 IpIfArr[], mDNSu32 OpIf)
{
(void) IpIfArr;
(void) OpIf;
}
mDNSexport void DNSProxyTerminate(void)
{
}
// mDNS core calls this routine to clear blocks of memory.
// On the Posix platform this is a simple wrapper around ANSI C memset.
mDNSexport void mDNSPlatformMemZero(void *dst, mDNSu32 len)
{
memset(dst, 0, len);
}
mDNSexport void * mDNSPlatformMemAllocate(mDNSu32 len) { return(malloc(len)); }
mDNSexport void mDNSPlatformMemFree (void *mem) { free(mem); }
#if _PLATFORM_HAS_STRONG_PRNG_
mDNSexport mDNSu32 mDNSPlatformRandomNumber(void)
{
return(arc4random());
}
#else
mDNSexport mDNSu32 mDNSPlatformRandomSeed(void)
{
struct timeval tv;
gettimeofday(&tv, NULL);
return(tv.tv_usec);
}
#endif
mDNSexport mDNSs32 mDNSPlatformOneSecond = 1024;
mDNSexport mStatus mDNSPlatformTimeInit(void)
{
// No special setup is required on Posix -- we just use gettimeofday();
// This is not really safe, because gettimeofday can go backwards if the user manually changes the date or time
// We should find a better way to do this
return(mStatus_NoError);
}
mDNSexport mDNSs32 mDNSPlatformRawTime()
{
struct timeval tv;
gettimeofday(&tv, NULL);
// tv.tv_sec is seconds since 1st January 1970 (GMT, with no adjustment for daylight savings time)
// tv.tv_usec is microseconds since the start of this second (i.e. values 0 to 999999)
// We use the lower 22 bits of tv.tv_sec for the top 22 bits of our result
// 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.
// This gives us a proper modular (cyclic) counter that has a resolution of roughly 1ms (actually 1/1024 second)
// and correctly cycles every 2^22 seconds (4194304 seconds = approx 48 days).
return((tv.tv_sec << 10) | (tv.tv_usec * 16 / 15625));
}
mDNSexport mDNSs32 mDNSPlatformUTC(void)
{
return time(NULL);
}
mDNSexport void mDNSPlatformSendWakeupPacket(mDNSInterfaceID InterfaceID, char *EthAddr, char *IPAddr, int iteration)
{
(void) InterfaceID;
(void) EthAddr;
(void) IPAddr;
(void) iteration;
}
mDNSexport mDNSBool mDNSPlatformValidRecordForInterface(const AuthRecord *rr, mDNSInterfaceID InterfaceID)
{
(void) rr;
(void) InterfaceID;
return 1;
}
mDNSexport mDNSBool mDNSPlatformValidQuestionForInterface(DNSQuestion *q, const NetworkInterfaceInfo *intf)
{
(void) q;
(void) intf;
return 1;
}
// Used for debugging purposes. For now, just set the buffer to zero
mDNSexport void mDNSPlatformFormatTime(unsigned long te, mDNSu8 *buf, int bufsize)
{
(void) te;
if (bufsize) buf[0] = 0;
}
mDNSexport void mDNSPlatformSendKeepalive(mDNSAddr *sadd, mDNSAddr *dadd, mDNSIPPort *lport, mDNSIPPort *rport, mDNSu32 seq, mDNSu32 ack, mDNSu16 win)
{
(void) sadd; // Unused
(void) dadd; // Unused
(void) lport; // Unused
(void) rport; // Unused
(void) seq; // Unused
(void) ack; // Unused
(void) win; // Unused
}
mDNSexport mStatus mDNSPlatformRetrieveTCPInfo(mDNSAddr *laddr, mDNSIPPort *lport, mDNSAddr *raddr, mDNSIPPort *rport, mDNSTCPInfo *mti)
{
(void) laddr; // Unused
(void) raddr; // Unused
(void) lport; // Unused
(void) rport; // Unused
(void) mti; // Unused
return mStatus_NoError;
}
mDNSexport mStatus mDNSPlatformGetRemoteMacAddr(mDNSAddr *raddr)
{
(void) raddr; // Unused
return mStatus_NoError;
}
mDNSexport mStatus mDNSPlatformStoreSPSMACAddr(mDNSAddr *spsaddr, char *ifname)
{
(void) spsaddr; // Unused
(void) ifname; // Unused
return mStatus_NoError;
}
mDNSexport mStatus mDNSPlatformClearSPSData(void)
{
return mStatus_NoError;
}
mDNSexport mStatus mDNSPlatformStoreOwnerOptRecord(char *ifname, DNSMessage *msg, int length)
{
(void) ifname; // Unused
(void) msg; // Unused
(void) length; // Unused
return mStatus_UnsupportedErr;
}
mDNSexport mDNSu16 mDNSPlatformGetUDPPort(UDPSocket *sock)
{
(void) sock; // unused
return (mDNSu16)-1;
}
mDNSexport mDNSBool mDNSPlatformInterfaceIsD2D(mDNSInterfaceID InterfaceID)
{
(void) InterfaceID; // unused
return mDNSfalse;
}
mDNSexport void mDNSPlatformSetSocktOpt(void *sock, mDNSTransport_Type transType, mDNSAddr_Type addrType, const DNSQuestion *q)
{
(void) sock;
(void) transType;
(void) addrType;
(void) q;
}
mDNSexport mDNSs32 mDNSPlatformGetPID()
{
return 0;
}
mDNSlocal void mDNSPosixAddToFDSet(int *nfds, fd_set *readfds, int s)
{
if (*nfds < s + 1) *nfds = s + 1;
FD_SET(s, readfds);
}
mDNSexport void mDNSPosixGetFDSet(mDNS *m, int *nfds, fd_set *readfds, struct timeval *timeout)
{
mDNSs32 ticks;
struct timeval interval;
// 1. Call mDNS_Execute() to let mDNSCore do what it needs to do
mDNSs32 nextevent = mDNS_Execute(m);
// 2. Build our list of active file descriptors
PosixNetworkInterface *info = (PosixNetworkInterface *)(m->HostInterfaces);
if (m->p->unicastSocket4 != -1) mDNSPosixAddToFDSet(nfds, readfds, m->p->unicastSocket4);
#if HAVE_IPV6
if (m->p->unicastSocket6 != -1) mDNSPosixAddToFDSet(nfds, readfds, m->p->unicastSocket6);
#endif
while (info)
{
if (info->multicastSocket4 != -1) mDNSPosixAddToFDSet(nfds, readfds, info->multicastSocket4);
#if HAVE_IPV6
if (info->multicastSocket6 != -1) mDNSPosixAddToFDSet(nfds, readfds, info->multicastSocket6);
#endif
info = (PosixNetworkInterface *)(info->coreIntf.next);
}
// 3. Calculate the time remaining to the next scheduled event (in struct timeval format)
ticks = nextevent - mDNS_TimeNow(m);
if (ticks < 1) ticks = 1;
interval.tv_sec = ticks >> 10; // The high 22 bits are seconds
interval.tv_usec = ((ticks & 0x3FF) * 15625) / 16; // The low 10 bits are 1024ths
// 4. If client's proposed timeout is more than what we want, then reduce it
if (timeout->tv_sec > interval.tv_sec ||
(timeout->tv_sec == interval.tv_sec && timeout->tv_usec > interval.tv_usec))
*timeout = interval;
}
mDNSexport void mDNSPosixProcessFDSet(mDNS *const m, fd_set *readfds)
{
PosixNetworkInterface *info;
assert(m != NULL);
assert(readfds != NULL);
info = (PosixNetworkInterface *)(m->HostInterfaces);
if (m->p->unicastSocket4 != -1 && FD_ISSET(m->p->unicastSocket4, readfds))
{
FD_CLR(m->p->unicastSocket4, readfds);
SocketDataReady(m, NULL, m->p->unicastSocket4);
}
#if HAVE_IPV6
if (m->p->unicastSocket6 != -1 && FD_ISSET(m->p->unicastSocket6, readfds))
{
FD_CLR(m->p->unicastSocket6, readfds);
SocketDataReady(m, NULL, m->p->unicastSocket6);
}
#endif
while (info)
{
if (info->multicastSocket4 != -1 && FD_ISSET(info->multicastSocket4, readfds))
{
FD_CLR(info->multicastSocket4, readfds);
SocketDataReady(m, info, info->multicastSocket4);
}
#if HAVE_IPV6
if (info->multicastSocket6 != -1 && FD_ISSET(info->multicastSocket6, readfds))
{
FD_CLR(info->multicastSocket6, readfds);
SocketDataReady(m, info, info->multicastSocket6);
}
#endif
info = (PosixNetworkInterface *)(info->coreIntf.next);
}
}
// update gMaxFD
mDNSlocal void DetermineMaxEventFD(void)
{
PosixEventSource *iSource;
gMaxFD = 0;
for (iSource=(PosixEventSource*)gEventSources.Head; iSource; iSource = iSource->Next)
if (gMaxFD < iSource->fd)
gMaxFD = iSource->fd;
}
// Add a file descriptor to the set that mDNSPosixRunEventLoopOnce() listens to.
mStatus mDNSPosixAddFDToEventLoop(int fd, mDNSPosixEventCallback callback, void *context)
{
PosixEventSource *newSource;
if (gEventSources.LinkOffset == 0)
InitLinkedList(&gEventSources, offsetof(PosixEventSource, Next));
if (fd >= (int) FD_SETSIZE || fd < 0)
return mStatus_UnsupportedErr;
if (callback == NULL)
return mStatus_BadParamErr;
newSource = (PosixEventSource*) malloc(sizeof *newSource);
if (NULL == newSource)
return mStatus_NoMemoryErr;
newSource->Callback = callback;
newSource->Context = context;
newSource->fd = fd;
AddToTail(&gEventSources, newSource);
FD_SET(fd, &gEventFDs);
DetermineMaxEventFD();
return mStatus_NoError;
}
// Remove a file descriptor from the set that mDNSPosixRunEventLoopOnce() listens to.
mStatus mDNSPosixRemoveFDFromEventLoop(int fd)
{
PosixEventSource *iSource;
for (iSource=(PosixEventSource*)gEventSources.Head; iSource; iSource = iSource->Next)
{
if (fd == iSource->fd)
{
FD_CLR(fd, &gEventFDs);
RemoveFromList(&gEventSources, iSource);
free(iSource);
DetermineMaxEventFD();
return mStatus_NoError;
}
}
return mStatus_NoSuchNameErr;
}
// Simply note the received signal in gEventSignals.
mDNSlocal void NoteSignal(int signum)
{
sigaddset(&gEventSignals, signum);
}
// Tell the event package to listen for signal and report it in mDNSPosixRunEventLoopOnce().
mStatus mDNSPosixListenForSignalInEventLoop(int signum)
{
struct sigaction action;
mStatus err;
mDNSPlatformMemZero(&action, sizeof action); // more portable than member-wise assignment
action.sa_handler = NoteSignal;
err = sigaction(signum, &action, (struct sigaction*) NULL);
sigaddset(&gEventSignalSet, signum);
return err;
}
// Tell the event package to stop listening for signal in mDNSPosixRunEventLoopOnce().
mStatus mDNSPosixIgnoreSignalInEventLoop(int signum)
{
struct sigaction action;
mStatus err;
mDNSPlatformMemZero(&action, sizeof action); // more portable than member-wise assignment
action.sa_handler = SIG_DFL;
err = sigaction(signum, &action, (struct sigaction*) NULL);
sigdelset(&gEventSignalSet, signum);
return err;
}
// Do a single pass through the attendent event sources and dispatch any found to their callbacks.
// Return as soon as internal timeout expires, or a signal we're listening for is received.
mStatus mDNSPosixRunEventLoopOnce(mDNS *m, const struct timeval *pTimeout,
sigset_t *pSignalsReceived, mDNSBool *pDataDispatched)
{
fd_set listenFDs = gEventFDs;
int fdMax = 0, numReady;
struct timeval timeout = *pTimeout;
// Include the sockets that are listening to the wire in our select() set
mDNSPosixGetFDSet(m, &fdMax, &listenFDs, &timeout); // timeout may get modified
if (fdMax < gMaxFD)
fdMax = gMaxFD;
numReady = select(fdMax + 1, &listenFDs, (fd_set*) NULL, (fd_set*) NULL, &timeout);
// If any data appeared, invoke its callback
if (numReady > 0)
{
PosixEventSource *iSource;
(void) mDNSPosixProcessFDSet(m, &listenFDs); // call this first to process wire data for clients
for (iSource=(PosixEventSource*)gEventSources.Head; iSource; iSource = iSource->Next)
{
if (FD_ISSET(iSource->fd, &listenFDs))
{
iSource->Callback(iSource->fd, 0, iSource->Context);
break; // in case callback removed elements from gEventSources
}
}
*pDataDispatched = mDNStrue;
}
else
*pDataDispatched = mDNSfalse;
(void) sigprocmask(SIG_BLOCK, &gEventSignalSet, (sigset_t*) NULL);
*pSignalsReceived = gEventSignals;
sigemptyset(&gEventSignals);
(void) sigprocmask(SIG_UNBLOCK, &gEventSignalSet, (sigset_t*) NULL);
return mStatus_NoError;
}
