1 files changed, 543 insertions, 0 deletions
diff --git a/mDNSResponder/mDNSMacOSX/DNSProxySupport.c b/mDNSResponder/mDNSMacOSX/DNSProxySupport.c
new file mode 100644
index 00000000..042bbc80
--- /dev/null
+++ b/mDNSResponder/mDNSMacOSX/DNSProxySupport.c
@@ -0,0 +1,543 @@
+/* -*- Mode: C; tab-width: 4 -*-
+ *
+ * Copyright (c) 2011 Apple Computer, 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"
+#include "mDNSMacOSX.h"
+
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/event.h>
+
+#define ValidSocket(s) ((s) >= 0)
+
+// Global to store the 4 DNS Proxy Listeners (UDPv4/6, TCPv4/6)
+static int dp_listener[4];
+
+#define NUM_PROXY_TCP_CONNS 100
+
+typedef struct
+{
+    TCPSocket   sock;
+    DNSMessage  *reply;
+    mDNSu16     replyLen;
+    mDNSu32     nread;
+} ProxyTCPInfo_t;
+
+// returns -1 for failures including the other end closing the socket
+// returns 0 if successful in reading data, but still not read the data fully
+// returns 1 if successful in reading all the data
+mDNSlocal int ProxyTCPRead(ProxyTCPInfo_t *tcpInfo)
+{
+    long n;
+    mDNSBool closed; 
+
+    if (tcpInfo->nread < 2)         // First read the two-byte length preceeding the DNS message
+    {
+        mDNSu8 *lenptr = (mDNSu8 *)&tcpInfo->replyLen;
+        n = mDNSPlatformReadTCP(&tcpInfo->sock, lenptr + tcpInfo->nread, 2 - tcpInfo->nread, &closed);
+        if (n < 0 || closed)
+        {
+            LogMsg("ProxyTCPRead: attempt to read message length failed");
+            return -1;
+        }
+
+        tcpInfo->nread += n;
+        if (tcpInfo->nread < 2)
+        {
+            LogMsg("ProxyTCPRead: nread %d, n %d", tcpInfo->nread, n);
+            return 0;
+        }
+
+        tcpInfo->replyLen = (mDNSu16)((mDNSu16)lenptr[0] << 8 | lenptr[1]);
+        if (tcpInfo->replyLen < sizeof(DNSMessageHeader))
+        {
+            LogMsg("ProxyTCPRead: Message length too short (%d bytes)", tcpInfo->replyLen);
+            return -1;
+        }
+
+        tcpInfo->reply = mallocL("ProxyTCPInfo", tcpInfo->replyLen);
+        if (!tcpInfo->reply)
+        {
+            LogMsg("ProxyTCPRead: Memory failure");
+            return -1;
+        }
+    }
+
+    n = mDNSPlatformReadTCP(&tcpInfo->sock, ((char *)tcpInfo->reply) + (tcpInfo->nread - 2), tcpInfo->replyLen - (tcpInfo->nread - 2), &closed);
+
+    if (n < 0 || closed)
+    {
+        LogMsg("ProxyTCPRead: read failure n %d, closed %d", n, closed);
+        return -1;
+    }
+    tcpInfo->nread += n;
+    if ((tcpInfo->nread - 2) != tcpInfo->replyLen)
+        return 0;
+    else 
+        return 1;
+}
+
+mDNSlocal void ProxyTCPSocketCallBack(int s1, short filter, void *context)
+{
+    int ret;
+    struct sockaddr_storage from;
+    struct sockaddr_storage to;
+    mDNSAddr senderAddr, destAddr;
+    mDNSIPPort senderPort;
+    ProxyTCPInfo_t *ti = (ProxyTCPInfo_t *)context;
+    TCPSocket *sock = &ti->sock;
+    KQSocketSet *kq = &sock->ss;
+
+    (void) filter;
+
+    ret = ProxyTCPRead(ti);
+    if (ret == -1)
+    {
+        mDNSPlatformDisposeProxyContext(ti);
+        return; 
+    }
+    else if (!ret)
+    {
+        debugf("ProxyTCPReceive: Not yet read completely Actual length %d, Read length %d", ti->replyLen, ti->nread);
+        return;
+    }
+    // We read all the data and hence not interested in read events anymore
+    KQueueSet(s1, EV_DELETE, EVFILT_READ, sock->kqEntry);
+
+    mDNSPlatformMemZero(&to, sizeof(to));
+    mDNSPlatformMemZero(&from, sizeof(from));
+    socklen_t len = sizeof(to);
+    ret = getsockname(s1, (struct sockaddr*) &to, &len);
+    if (ret < 0)
+    {
+        LogMsg("ProxyTCPReceive: getsockname(fd=%d) errno %d", s1, errno);
+        mDNSPlatformDisposeProxyContext(ti);
+        return;
+    }
+    ret = getpeername(s1, (struct sockaddr*) &from, &len);
+    if (ret < 0)
+    {
+        LogMsg("ProxyTCPReceive: getpeername(fd=%d) errno %d", s1, errno);
+        mDNSPlatformDisposeProxyContext(ti);
+        return;
+    }
+
+    if (from.ss_family == AF_INET)
+    {
+        struct sockaddr_in *s = (struct sockaddr_in*)&from;
+
+        senderAddr.type = mDNSAddrType_IPv4;
+        senderAddr.ip.v4.NotAnInteger = s->sin_addr.s_addr;
+        senderPort.NotAnInteger = s->sin_port;
+
+        s = (struct sockaddr_in *)&to;
+        destAddr.type = mDNSAddrType_IPv4;
+        destAddr.ip.v4.NotAnInteger = s->sin_addr.s_addr;
+
+        LogInfo("ProxyTCPReceive received IPv4 packet(len %d) from %#-15a to %#-15a on skt %d %s", ti->replyLen, &senderAddr, &destAddr, s1, NULL);
+    }
+    else if (from.ss_family == AF_INET6)
+    {
+        struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)&from;
+        senderAddr.type = mDNSAddrType_IPv6;
+        senderAddr.ip.v6 = *(mDNSv6Addr*)&sin6->sin6_addr;
+        senderPort.NotAnInteger = sin6->sin6_port;
+
+        sin6 = (struct sockaddr_in6 *)&to;
+        destAddr.type = mDNSAddrType_IPv6;
+        destAddr.ip.v6 = *(mDNSv6Addr*)&sin6->sin6_addr;
+
+        LogInfo("ProxyTCPReceive received IPv6 packet(len %d) from %#-15a to %#-15a on skt %d %s", ti->replyLen, &senderAddr, &destAddr, s1, NULL);
+    }
+    else
+    {
+        LogMsg("ProxyTCPReceive from is unknown address family %d", from.ss_family);
+        mDNSPlatformDisposeProxyContext(ti);
+        return;
+    }
+
+    // We pass sock for the TCPSocket and the "ti" for context as that's what we want to free at the end.
+    // In the UDP case, there is just a single socket and nothing to free. Hence, the context (last argument)
+    // would be NULL.
+    kq->m->p->TCPProxyCallback(kq->m, sock, ti->reply, (mDNSu8 *)ti->reply + ti->replyLen, &senderAddr, senderPort, &destAddr,
+        UnicastDNSPort, 0, ti);
+}
+
+mDNSlocal void ProxyTCPAccept(int s1, short filter, void *context)
+{
+    int newfd;
+    struct sockaddr_storage ss;
+    socklen_t sslen = sizeof(ss);
+    const int on = 1;
+    KQSocketSet *listenSet = (KQSocketSet *)context;
+
+    (void) filter;
+
+    while ((newfd = accept(s1, (struct sockaddr *)&ss, &sslen)) != -1)
+    {
+        int err;
+        int *s;
+        KQueueEntry *k;
+        KQSocketSet *kq;
+
+        // Even though we just need a single KQueueEntry, for simplicity we re-use
+        // the KQSocketSet
+        ProxyTCPInfo_t *ti = mallocL("ProxyTCPContext", sizeof(ProxyTCPInfo_t));
+        if (!ti)
+        {
+            LogMsg("ProxyTCPAccept: cannot allocate TCPSocket");
+            close(newfd);
+            return;
+        }
+        mDNSPlatformMemZero(ti, sizeof(ProxyTCPInfo_t));
+        TCPSocket *sock = &ti->sock;
+
+        kq = &sock->ss;
+        kq->sktv4 = -1;
+        kq->sktv6 = -1;
+        kq->m = listenSet->m;
+
+        fcntl(newfd, F_SETFL, fcntl(newfd, F_GETFL, 0) | O_NONBLOCK); // set non-blocking
+        if (ss.ss_family == AF_INET)
+        {
+            s =  &kq->sktv4;
+            k =  &kq->kqsv4;
+            // Receive interface identifiers
+            err = setsockopt(newfd, IPPROTO_IP, IP_RECVIF, &on, sizeof(on));
+            if (err)
+            {
+                LogMsg("ProxyTCPAccept: IP_RECVIF %d errno %d (%s)", newfd, errno, strerror(errno));
+                mDNSPlatformDisposeProxyContext(ti);
+                return;
+            }
+        }
+        else
+        {
+            s =  &kq->sktv6;
+            k =  &kq->kqsv6;
+            // We want to receive destination addresses and receive interface identifiers
+            err = setsockopt(newfd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &on, sizeof(on));
+            if (err)
+            {
+                LogMsg("ProxyTCPAccept: IP_RECVPKTINFO %d errno %d (%s)", newfd, errno, strerror(errno));
+                mDNSPlatformDisposeProxyContext(ti);
+                return;
+            }
+        }
+        *s = newfd;
+        // mDNSPlatformReadTCP/WriteTCP (unlike the UDP counterpart) does not provide the destination address
+        // from which we can infer the destination address family. Hence we need to remember that here.
+        // Instead of remembering the address family, we remember the right fd.
+        sock->fd = newfd;
+        sock->kqEntry = k;
+
+        k->KQcallback = ProxyTCPSocketCallBack;
+        k->KQcontext  = ti;
+        k->KQtask     = "TCP Proxy packet reception";
+#ifdef MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM
+        k->readSource = mDNSNULL;
+        k->writeSource = mDNSNULL;
+        k->fdClosed = mDNSfalse;
+#endif
+        KQueueSet(*s, EV_ADD, EVFILT_READ, k);
+    }
+}
+
+mDNSlocal mStatus SetupUDPProxySocket(mDNS *const m, int skt, KQSocketSet *cp, u_short sa_family, mDNSBool useBackgroundTrafficClass)
+{
+    int         *s        = (sa_family == AF_INET) ? &cp->sktv4 : &cp->sktv6;
+    KQueueEntry *k        = (sa_family == AF_INET) ? &cp->kqsv4 : &cp->kqsv6;
+    const int on = 1;
+    mDNSIPPort port;
+    mStatus err = mStatus_NoError;
+
+    cp->m = m;
+    port = cp->port;
+    cp->closeFlag = mDNSNULL;
+
+    // set default traffic class
+    // setTrafficClass(skt, mDNSfalse);
+    (void) useBackgroundTrafficClass;
+
+    if (sa_family == AF_INET)
+    {
+        err = setsockopt(skt, IPPROTO_IP, IP_RECVDSTADDR, &on, sizeof(on));
+        if (err < 0)
+        {
+            LogMsg("SetupUDPProxySocket: IP_RECVDSTADDR %d errno %d (%s)", skt, errno, strerror(errno));
+            return err;
+        }
+
+        // We want to receive interface identifiers
+        err = setsockopt(skt, IPPROTO_IP, IP_RECVIF, &on, sizeof(on));
+        if (err < 0)
+        {
+            LogMsg("SetupUDPProxySocket: IP_RECVIF %d errno %d (%s)", skt, errno, strerror(errno));
+            return err;
+        }
+    }
+    else if (sa_family == AF_INET6)
+    {
+        // We want to receive destination addresses and receive interface identifiers
+        err = setsockopt(skt, IPPROTO_IPV6, IPV6_RECVPKTINFO, &on, sizeof(on));
+        if (err < 0)
+        {
+            LogMsg("SetupUDPProxySocket: IPV6_RECVPKTINFO %d errno %d (%s)", skt, errno, strerror(errno));
+            return err;
+        }
+
+        // We want to receive packet hop count value so we can check it
+        err = setsockopt(skt, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &on, sizeof(on));
+        if (err < 0)
+        {
+            LogMsg("SetupUDPProxySocket: IPV6_RECVHOPLIMIT %d errno %d (%s)", skt, errno, strerror(errno));
+            return err;
+        }
+    }
+    else
+    {
+        LogMsg("SetupUDPProxySocket: wrong family %d", sa_family);
+        return -1;
+    }
+
+    if (fcntl(skt, F_SETFL, fcntl(skt, F_GETFL, 0) | O_NONBLOCK) < 0)
+    {
+        LogMsg("SetupUDPProxySocket: fnctl failed %d", errno);
+        return -1;
+    }
+
+    *s = skt;
+    //k->KQcallback = ProxyUDPSocketCallBack;
+    k->KQcallback  = myKQSocketCallBack;
+    k->KQcontext   = cp;
+    k->KQtask      = "UDP Proxy packet reception";
+#ifdef MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM
+    k->readSource  = mDNSNULL;
+    k->writeSource = mDNSNULL;
+    k->fdClosed    = mDNSfalse;
+#endif
+
+    KQueueSet(*s, EV_ADD, EVFILT_READ, k);
+
+    return(err);
+}
+
+mDNSlocal mStatus SetupTCPProxySocket(mDNS *const m, int skt, KQSocketSet *cp, u_short sa_family, mDNSBool useBackgroundTrafficClass)
+{
+    int         *s        = (sa_family == AF_INET) ? &cp->sktv4 : &cp->sktv6;
+    KQueueEntry *k        = (sa_family == AF_INET) ? &cp->kqsv4 : &cp->kqsv6;
+    mDNSIPPort port;
+    mStatus err;
+
+    cp->m = m;
+    port = cp->port;
+    // XXX may not be used by the TCP codepath 
+    cp->closeFlag = mDNSNULL;
+
+    // for TCP sockets, the traffic class is set once and not changed
+    // setTrafficClass(skt, useBackgroundTrafficClass);
+    (void) useBackgroundTrafficClass;
+
+    // All the socket setup has already been done 
+    err = listen(skt, NUM_PROXY_TCP_CONNS);
+    if (err)
+    {
+        LogMsg("SetupTCPProxySocket: listen %d errno %d (%s)", skt, errno, strerror(errno));
+        return err;
+    }
+    fcntl(skt, F_SETFL, fcntl(skt, F_GETFL, 0) | O_NONBLOCK); // set non-blocking
+    
+    *s = skt;
+    k->KQcallback  = ProxyTCPAccept;
+    k->KQcontext   = cp;
+    k->KQtask      = "TCP Accept";
+#ifdef MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM
+    k->readSource  = mDNSNULL;
+    k->writeSource = mDNSNULL;
+    k->fdClosed    = mDNSfalse;
+#endif
+    KQueueSet(*s, EV_ADD, EVFILT_READ, k);
+    return mStatus_NoError;
+}
+
+mDNSlocal void BindDPSocket(int fd, int sa_family)
+{
+    int err;
+    const int on = 1;
+
+    if (sa_family == AF_INET)
+    {
+        struct sockaddr_in addr;
+
+        err = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &on, sizeof(on));
+        if (err < 0) 
+            LogMsg("BindDPSocket: setsockopt SO_REUSEPORT failed for V4 %d errno %d (%s)", fd, errno, strerror(errno));
+
+        memset(&addr, 0, sizeof(addr));
+        addr.sin_family = AF_INET;
+        addr.sin_port = htons(53);
+
+        err = bind(fd, (struct sockaddr*) &addr, sizeof(addr));
+        if (err)
+        {
+            LogMsg("BindDPSocket: bind %d errno %d (%s)", fd, errno, strerror(errno));
+            return;
+        }
+    }
+    else
+    {
+        struct sockaddr_in6 addr6;
+
+        // We want to receive only IPv6 packets. Without this option we get IPv4 packets too,
+        // with mapped addresses of the form 0:0:0:0:0:FFFF:xxxx:xxxx, where xxxx:xxxx is the IPv4 address
+        err = setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on));
+        if (err < 0)
+        {
+            LogMsg("DPFBindSocket: setsockopt IPV6_V6ONLY %d errno %d (%s)", fd, errno, strerror(errno));
+            return;
+        }
+        err = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &on, sizeof(on));
+        if (err < 0)
+            LogMsg("BindDPSocket: setsockopt SO_REUSEPORT failed for V6 %d errno %d (%s)", fd, errno, strerror(errno));
+
+        memset(&addr6, 0, sizeof(addr6));
+        addr6.sin6_family = AF_INET6;
+        addr6.sin6_port = htons(53);
+
+        err = bind(fd, (struct sockaddr*) &addr6, sizeof(addr6));
+        if (err)
+        {
+            LogMsg("BindDPSocket: bind6 %d errno %d (%s)", fd, errno, strerror(errno));
+            return;
+        }
+    }
+}
+
+// Setup DNS Proxy Skts in main kevent loop and set the skt options
+mDNSlocal void SetupDNSProxySkts(mDNS *const m, int fd[4])
+{
+    int i;
+    mStatus err;
+    KQSocketSet *udpSS;
+    KQSocketSet *tcpSS;
+
+    udpSS       = &m->p->UDPProxy.ss;
+    tcpSS       = &m->p->TCPProxy.ss;
+    udpSS->port = UnicastDNSPort;
+    tcpSS->port = UnicastDNSPort;
+
+    LogMsg("SetupDNSProxySkts: %d, %d, %d, %d", fd[0], fd[1], fd[2], fd[3]);
+
+    // myKQSocketCallBack checks for proxy and calls the m->p->ProxyCallback instead of mDNSCoreReceive
+    udpSS->proxy = mDNStrue;
+    err = SetupUDPProxySocket(m, fd[0], udpSS, AF_INET, mDNSfalse);
+    if (err)
+        LogMsg("SetupDNSProxySkts: ERROR!! UDPv4 Socket");
+
+    err = SetupUDPProxySocket(m, fd[1], udpSS, AF_INET6, mDNSfalse);
+    if (err)
+        LogMsg("SetupDNSProxySkts: ERROR!! UDPv6 Socket");
+
+    err = SetupTCPProxySocket(m, fd[2], tcpSS, AF_INET, mDNSfalse);
+    if (err)
+        LogMsg("SetupDNSProxySkts: ERROR!! TCPv4 Socket");
+
+    err = SetupTCPProxySocket(m, fd[3], tcpSS, AF_INET6, mDNSfalse);
+    if (err)
+        LogMsg("SetupDNSProxySkts: ERROR!! TCPv6 Socket");
+
+    for (i = 0; i < 4; i++)
+        dp_listener[i] = fd[i];   
+} 
+
+// Create and bind the DNS Proxy Skts for use
+mDNSexport void mDNSPlatformInitDNSProxySkts(mDNS *const m, ProxyCallback UDPCallback, ProxyCallback TCPCallback)
+{
+    int dpskt[4];
+    
+    dpskt[0] = socket(AF_INET,  SOCK_DGRAM,  IPPROTO_UDP);
+    dpskt[1] = socket(AF_INET6, SOCK_DGRAM,  IPPROTO_UDP);
+    dpskt[2] = socket(AF_INET,  SOCK_STREAM, IPPROTO_TCP);
+    dpskt[3] = socket(AF_INET6, SOCK_STREAM, IPPROTO_TCP);
+
+    // Close all DNS Proxy skts in case any of them are invalid
+    if (!ValidSocket(dpskt[0]) || !ValidSocket(dpskt[1]) ||
+        !ValidSocket(dpskt[2]) || !ValidSocket(dpskt[3]))
+    {   
+        if (ValidSocket(dpskt[0]))
+            close(dpskt[0]);
+        if (ValidSocket(dpskt[1]))
+            close(dpskt[1]);
+        if (ValidSocket(dpskt[2]))
+            close(dpskt[2]);
+        if (ValidSocket(dpskt[3]))
+            close(dpskt[3]);
+    }
+
+    BindDPSocket(dpskt[0], AF_INET);
+    BindDPSocket(dpskt[1], AF_INET6);
+    BindDPSocket(dpskt[2], AF_INET);
+    BindDPSocket(dpskt[3], AF_INET6);
+
+    LogInfo("mDNSPlatformInitDNSProxySkts: Opened Listener Sockets for DNS Proxy : %d, %d, %d, %d", 
+             dpskt[0], dpskt[1], dpskt[2], dpskt[3]);
+
+    m->p->UDPProxyCallback = UDPCallback;
+    m->p->TCPProxyCallback = TCPCallback;
+
+    SetupDNSProxySkts(m, dpskt);
+}
+
+mDNSexport void mDNSPlatformCloseDNSProxySkts(mDNS *const m)
+{
+    (void) m;
+    int i;
+    for (i = 0; i < 4; i++)
+        close(dp_listener[i]);
+    LogInfo("mDNSPlatformCloseDNSProxySkts: Closing DNS Proxy Listener Sockets");  
+}
+
+mDNSexport void mDNSPlatformDisposeProxyContext(void *context)
+{
+    ProxyTCPInfo_t *ti;
+    TCPSocket *sock;
+    KQSocketSet *kq;
+
+    if (!context)
+        return;
+
+    ti = (ProxyTCPInfo_t *)context;
+    sock = &ti->sock;
+
+    kq = &sock->ss;
+    if (kq->sktv4 != -1)
+    {
+        shutdown(kq->sktv4, 2);
+        mDNSPlatformCloseFD(&kq->kqsv4, kq->sktv4);
+    }
+    if (kq->sktv6 != -1)
+    {
+        shutdown(kq->sktv6, 2);
+        mDNSPlatformCloseFD(&kq->kqsv6, kq->sktv6);
+    }
+    if (kq->closeFlag)
+        *kq->closeFlag = 1;
+
+    if (ti->reply)
+        freeL("ProxyTCPInfoLen", ti->reply);
+    freeL("ProxyTCPContext", ti);
+}
+