mDNSMacOSX/DNSProxySupport.c

   1 /* -*- Mode: C; tab-width: 4 -*-
   2  *
   3  * Copyright (c) 2011 Apple Computer, Inc. All rights reserved.
   4  *
   5  * Licensed under the Apache License, Version 2.0 (the "License");
   6  * you may not use this file except in compliance with the License.
   7  * You may obtain a copy of the License at
   8  *
   9  *     http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing, software
  12  * distributed under the License is distributed on an "AS IS" BASIS,
  13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14  * See the License for the specific language governing permissions and
  15  * limitations under the License.
  16  */
  17 #include "mDNSEmbeddedAPI.h"
  18 #include "mDNSMacOSX.h"
  19
  20 #include <sys/types.h>
  21 #include <sys/time.h>
  22 #include <sys/event.h>
  23
  24 #define ValidSocket(s) ((s) >= 0)
  25
  26 // Global to store the 4 DNS Proxy Listeners (UDPv4/6, TCPv4/6)
  27 static int dp_listener[4];
  28
  29 #define NUM_PROXY_TCP_CONNS 100
  30
  31 typedef struct
  32 {
  33     TCPSocket   sock;
  34     DNSMessage  *reply;
  35     mDNSu16     replyLen;
  36     mDNSu32     nread;
  37 } ProxyTCPInfo_t;
  38
  39 // returns -1 for failures including the other end closing the socket
  40 // returns 0 if successful in reading data, but still not read the data fully
  41 // returns 1 if successful in reading all the data
  42 mDNSlocal int ProxyTCPRead(ProxyTCPInfo_t *tcpInfo)
  43 {
  44     long n;
  45     mDNSBool closed;
  46
  47     if (tcpInfo->nread < 2)         // First read the two-byte length preceeding the DNS message
  48     {
  49         mDNSu8 *lenptr = (mDNSu8 *)&tcpInfo->replyLen;
  50         n = mDNSPlatformReadTCP(&tcpInfo->sock, lenptr + tcpInfo->nread, 2 - tcpInfo->nread, &closed);
  51         if (n < 0 || closed)
  52         {
  53             LogMsg("ProxyTCPRead: attempt to read message length failed");
  54             return -1;
  55         }
  56
  57         tcpInfo->nread += n;
  58         if (tcpInfo->nread < 2)
  59         {
  60             LogMsg("ProxyTCPRead: nread %d, n %d", tcpInfo->nread, n);
  61             return 0;
  62         }
  63
  64         tcpInfo->replyLen = (mDNSu16)((mDNSu16)lenptr[0] << 8 | lenptr[1]);
  65         if (tcpInfo->replyLen < sizeof(DNSMessageHeader))
  66         {
  67             LogMsg("ProxyTCPRead: Message length too short (%d bytes)", tcpInfo->replyLen);
  68             return -1;
  69         }
  70
  71         tcpInfo->reply = mallocL("ProxyTCPInfo", tcpInfo->replyLen);
  72         if (!tcpInfo->reply)
  73         {
  74             LogMsg("ProxyTCPRead: Memory failure");
  75             return -1;
  76         }
  77     }
  78
  79     n = mDNSPlatformReadTCP(&tcpInfo->sock, ((char *)tcpInfo->reply) + (tcpInfo->nread - 2), tcpInfo->replyLen - (tcpInfo->nread - 2), &closed);
  80
  81     if (n < 0 || closed)
  82     {
  83         LogMsg("ProxyTCPRead: read failure n %d, closed %d", n, closed);
  84         return -1;
  85     }
  86     tcpInfo->nread += n;
  87     if ((tcpInfo->nread - 2) != tcpInfo->replyLen)
  88         return 0;
  89     else
  90         return 1;
  91 }
  92
  93 mDNSlocal void ProxyTCPSocketCallBack(int s1, short filter, void *context)
  94 {
  95     int ret;
  96     struct sockaddr_storage from;
  97     struct sockaddr_storage to;
  98     mDNSAddr senderAddr, destAddr;
  99     mDNSIPPort senderPort;
 100     ProxyTCPInfo_t *ti = (ProxyTCPInfo_t *)context;
 101     TCPSocket *sock = &ti->sock;
 102     KQSocketSet *kq = &sock->ss;
 103
 104     (void) filter;
 105
 106     ret = ProxyTCPRead(ti);
 107     if (ret == -1)
 108     {
 109         mDNSPlatformDisposeProxyContext(ti);
 110         return;
 111     }
 112     else if (!ret)
 113     {
 114         debugf("ProxyTCPReceive: Not yet read completely Actual length %d, Read length %d", ti->replyLen, ti->nread);
 115         return;
 116     }
 117     // We read all the data and hence not interested in read events anymore
 118     KQueueSet(s1, EV_DELETE, EVFILT_READ, sock->kqEntry);
 119
 120     mDNSPlatformMemZero(&to, sizeof(to));
 121     mDNSPlatformMemZero(&from, sizeof(from));
 122     socklen_t len = sizeof(to);
 123     ret = getsockname(s1, (struct sockaddr*) &to, &len);
 124     if (ret < 0)
 125     {
 126         LogMsg("ProxyTCPReceive: getsockname(fd=%d) errno %d", s1, errno);
 127         mDNSPlatformDisposeProxyContext(ti);
 128         return;
 129     }
 130     ret = getpeername(s1, (struct sockaddr*) &from, &len);
 131     if (ret < 0)
 132     {
 133         LogMsg("ProxyTCPReceive: getpeername(fd=%d) errno %d", s1, errno);
 134         mDNSPlatformDisposeProxyContext(ti);
 135         return;
 136     }
 137
 138     if (from.ss_family == AF_INET)
 139     {
 140         struct sockaddr_in *s = (struct sockaddr_in*)&from;
 141
 142         senderAddr.type = mDNSAddrType_IPv4;
 143         senderAddr.ip.v4.NotAnInteger = s->sin_addr.s_addr;
 144         senderPort.NotAnInteger = s->sin_port;
 145
 146         s = (struct sockaddr_in *)&to;
 147         destAddr.type = mDNSAddrType_IPv4;
 148         destAddr.ip.v4.NotAnInteger = s->sin_addr.s_addr;
 149
 150         LogInfo("ProxyTCPReceive received IPv4 packet(len %d) from %#-15a to %#-15a on skt %d %s", ti->replyLen, &senderAddr, &destAddr, s1, NULL);
 151     }
 152     else if (from.ss_family == AF_INET6)
 153     {
 154         struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)&from;
 155         senderAddr.type = mDNSAddrType_IPv6;
 156         senderAddr.ip.v6 = *(mDNSv6Addr*)&sin6->sin6_addr;
 157         senderPort.NotAnInteger = sin6->sin6_port;
 158
 159         sin6 = (struct sockaddr_in6 *)&to;
 160         destAddr.type = mDNSAddrType_IPv6;
 161         destAddr.ip.v6 = *(mDNSv6Addr*)&sin6->sin6_addr;
 162
 163         LogInfo("ProxyTCPReceive received IPv6 packet(len %d) from %#-15a to %#-15a on skt %d %s", ti->replyLen, &senderAddr, &destAddr, s1, NULL);
 164     }
 165     else
 166     {
 167         LogMsg("ProxyTCPReceive from is unknown address family %d", from.ss_family);
 168         mDNSPlatformDisposeProxyContext(ti);
 169         return;
 170     }
 171
 172     // We pass sock for the TCPSocket and the "ti" for context as that's what we want to free at the end.
 173     // In the UDP case, there is just a single socket and nothing to free. Hence, the context (last argument)
 174     // would be NULL.
 175     kq->m->p->TCPProxyCallback(kq->m, sock, ti->reply, (mDNSu8 *)ti->reply + ti->replyLen, &senderAddr, senderPort, &destAddr,
 176         UnicastDNSPort, 0, ti);
 177 }
 178
 179 mDNSlocal void ProxyTCPAccept(int s1, short filter, void *context)
 180 {
 181     int newfd;
 182     struct sockaddr_storage ss;
 183     socklen_t sslen = sizeof(ss);
 184     const int on = 1;
 185     KQSocketSet *listenSet = (KQSocketSet *)context;
 186
 187     (void) filter;
 188
 189     while ((newfd = accept(s1, (struct sockaddr *)&ss, &sslen)) != -1)
 190     {
 191         int err;
 192         int *s;
 193         KQueueEntry *k;
 194         KQSocketSet *kq;
 195
 196         // Even though we just need a single KQueueEntry, for simplicity we re-use
 197         // the KQSocketSet
 198         ProxyTCPInfo_t *ti = mallocL("ProxyTCPContext", sizeof(ProxyTCPInfo_t));
 199         if (!ti)
 200         {
 201             LogMsg("ProxyTCPAccept: cannot allocate TCPSocket");
 202             close(newfd);
 203             return;
 204         }
 205         mDNSPlatformMemZero(ti, sizeof(ProxyTCPInfo_t));
 206         TCPSocket *sock = &ti->sock;
 207
 208         kq = &sock->ss;
 209         kq->sktv4 = -1;
 210         kq->sktv6 = -1;
 211         kq->m = listenSet->m;
 212
 213         fcntl(newfd, F_SETFL, fcntl(newfd, F_GETFL, 0) | O_NONBLOCK); // set non-blocking
 214         if (ss.ss_family == AF_INET)
 215         {
 216             s =  &kq->sktv4;
 217             k =  &kq->kqsv4;
 218             // Receive interface identifiers
 219             err = setsockopt(newfd, IPPROTO_IP, IP_RECVIF, &on, sizeof(on));
 220             if (err)
 221             {
 222                 LogMsg("ProxyTCPAccept: IP_RECVIF %d errno %d (%s)", newfd, errno, strerror(errno));
 223                 mDNSPlatformDisposeProxyContext(ti);
 224                 return;
 225             }
 226         }
 227         else
 228         {
 229             s =  &kq->sktv6;
 230             k =  &kq->kqsv6;
 231             // We want to receive destination addresses and receive interface identifiers
 232             err = setsockopt(newfd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &on, sizeof(on));
 233             if (err)
 234             {
 235                 LogMsg("ProxyTCPAccept: IP_RECVPKTINFO %d errno %d (%s)", newfd, errno, strerror(errno));
 236                 mDNSPlatformDisposeProxyContext(ti);
 237                 return;
 238             }
 239         }
 240         *s = newfd;
 241         // mDNSPlatformReadTCP/WriteTCP (unlike the UDP counterpart) does not provide the destination address
 242         // from which we can infer the destination address family. Hence we need to remember that here.
 243         // Instead of remembering the address family, we remember the right fd.
 244         sock->fd = newfd;
 245         sock->kqEntry = k;
 246
 247         k->KQcallback = ProxyTCPSocketCallBack;
 248         k->KQcontext  = ti;
 249         k->KQtask     = "TCP Proxy packet reception";
 250 #ifdef MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM
 251         k->readSource = mDNSNULL;
 252         k->writeSource = mDNSNULL;
 253         k->fdClosed = mDNSfalse;
 254 #endif
 255         KQueueSet(*s, EV_ADD, EVFILT_READ, k);
 256     }
 257 }
 258
 259 mDNSlocal mStatus SetupUDPProxySocket(mDNS *const m, int skt, KQSocketSet *cp, u_short sa_family, mDNSBool useBackgroundTrafficClass)
 260 {
 261     int         *s        = (sa_family == AF_INET) ? &cp->sktv4 : &cp->sktv6;
 262     KQueueEntry *k        = (sa_family == AF_INET) ? &cp->kqsv4 : &cp->kqsv6;
 263     const int on = 1;
 264     mDNSIPPort port;
 265     mStatus err = mStatus_NoError;
 266
 267     cp->m = m;
 268     port = cp->port;
 269     cp->closeFlag = mDNSNULL;
 270
 271     // set default traffic class
 272     // setTrafficClass(skt, mDNSfalse);
 273     (void) useBackgroundTrafficClass;
 274
 275     if (sa_family == AF_INET)
 276     {
 277         err = setsockopt(skt, IPPROTO_IP, IP_RECVDSTADDR, &on, sizeof(on));
 278         if (err < 0)
 279         {
 280             LogMsg("SetupUDPProxySocket: IP_RECVDSTADDR %d errno %d (%s)", skt, errno, strerror(errno));
 281             return err;
 282         }
 283
 284         // We want to receive interface identifiers
 285         err = setsockopt(skt, IPPROTO_IP, IP_RECVIF, &on, sizeof(on));
 286         if (err < 0)
 287         {
 288             LogMsg("SetupUDPProxySocket: IP_RECVIF %d errno %d (%s)", skt, errno, strerror(errno));
 289             return err;
 290         }
 291     }
 292     else if (sa_family == AF_INET6)
 293     {
 294         // We want to receive destination addresses and receive interface identifiers
 295         err = setsockopt(skt, IPPROTO_IPV6, IPV6_RECVPKTINFO, &on, sizeof(on));
 296         if (err < 0)
 297         {
 298             LogMsg("SetupUDPProxySocket: IPV6_RECVPKTINFO %d errno %d (%s)", skt, errno, strerror(errno));
 299             return err;
 300         }
 301
 302         // We want to receive packet hop count value so we can check it
 303         err = setsockopt(skt, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &on, sizeof(on));
 304         if (err < 0)
 305         {
 306             LogMsg("SetupUDPProxySocket: IPV6_RECVHOPLIMIT %d errno %d (%s)", skt, errno, strerror(errno));
 307             return err;
 308         }
 309     }
 310     else
 311     {
 312         LogMsg("SetupUDPProxySocket: wrong family %d", sa_family);
 313         return -1;
 314     }
 315
 316     if (fcntl(skt, F_SETFL, fcntl(skt, F_GETFL, 0) | O_NONBLOCK) < 0)
 317     {
 318         LogMsg("SetupUDPProxySocket: fnctl failed %d", errno);
 319         return -1;
 320     }
 321
 322     *s = skt;
 323     //k->KQcallback = ProxyUDPSocketCallBack;
 324     k->KQcallback  = myKQSocketCallBack;
 325     k->KQcontext   = cp;
 326     k->KQtask      = "UDP Proxy packet reception";
 327 #ifdef MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM
 328     k->readSource  = mDNSNULL;
 329     k->writeSource = mDNSNULL;
 330     k->fdClosed    = mDNSfalse;
 331 #endif
 332
 333     KQueueSet(*s, EV_ADD, EVFILT_READ, k);
 334
 335     return(err);
 336 }
 337
 338 mDNSlocal mStatus SetupTCPProxySocket(mDNS *const m, int skt, KQSocketSet *cp, u_short sa_family, mDNSBool useBackgroundTrafficClass)
 339 {
 340     int         *s        = (sa_family == AF_INET) ? &cp->sktv4 : &cp->sktv6;
 341     KQueueEntry *k        = (sa_family == AF_INET) ? &cp->kqsv4 : &cp->kqsv6;
 342     mDNSIPPort port;
 343     mStatus err;
 344
 345     cp->m = m;
 346     port = cp->port;
 347     // XXX may not be used by the TCP codepath
 348     cp->closeFlag = mDNSNULL;
 349
 350     // for TCP sockets, the traffic class is set once and not changed
 351     // setTrafficClass(skt, useBackgroundTrafficClass);
 352     (void) useBackgroundTrafficClass;
 353
 354     // All the socket setup has already been done
 355     err = listen(skt, NUM_PROXY_TCP_CONNS);
 356     if (err)
 357     {
 358         LogMsg("SetupTCPProxySocket: listen %d errno %d (%s)", skt, errno, strerror(errno));
 359         return err;
 360     }
 361     fcntl(skt, F_SETFL, fcntl(skt, F_GETFL, 0) | O_NONBLOCK); // set non-blocking
 362
 363     *s = skt;
 364     k->KQcallback  = ProxyTCPAccept;
 365     k->KQcontext   = cp;
 366     k->KQtask      = "TCP Accept";
 367 #ifdef MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM
 368     k->readSource  = mDNSNULL;
 369     k->writeSource = mDNSNULL;
 370     k->fdClosed    = mDNSfalse;
 371 #endif
 372     KQueueSet(*s, EV_ADD, EVFILT_READ, k);
 373     return mStatus_NoError;
 374 }
 375
 376 mDNSlocal void BindDPSocket(int fd, int sa_family)
 377 {
 378     int err;
 379     const int on = 1;
 380
 381     if (sa_family == AF_INET)
 382     {
 383         struct sockaddr_in addr;
 384
 385         err = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &on, sizeof(on));
 386         if (err < 0)
 387             LogMsg("BindDPSocket: setsockopt SO_REUSEPORT failed for V4 %d errno %d (%s)", fd, errno, strerror(errno));
 388
 389         memset(&addr, 0, sizeof(addr));
 390         addr.sin_family = AF_INET;
 391         addr.sin_port = htons(53);
 392
 393         err = bind(fd, (struct sockaddr*) &addr, sizeof(addr));
 394         if (err)
 395         {
 396             LogMsg("BindDPSocket: bind %d errno %d (%s)", fd, errno, strerror(errno));
 397             return;
 398         }
 399     }
 400     else
 401     {
 402         struct sockaddr_in6 addr6;
 403
 404         // We want to receive only IPv6 packets. Without this option we get IPv4 packets too,
 405         // with mapped addresses of the form 0:0:0:0:0:FFFF:xxxx:xxxx, where xxxx:xxxx is the IPv4 address
 406         err = setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on));
 407         if (err < 0)
 408         {
 409             LogMsg("DPFBindSocket: setsockopt IPV6_V6ONLY %d errno %d (%s)", fd, errno, strerror(errno));
 410             return;
 411         }
 412         err = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &on, sizeof(on));
 413         if (err < 0)
 414             LogMsg("BindDPSocket: setsockopt SO_REUSEPORT failed for V6 %d errno %d (%s)", fd, errno, strerror(errno));
 415
 416         memset(&addr6, 0, sizeof(addr6));
 417         addr6.sin6_family = AF_INET6;
 418         addr6.sin6_port = htons(53);
 419
 420         err = bind(fd, (struct sockaddr*) &addr6, sizeof(addr6));
 421         if (err)
 422         {
 423             LogMsg("BindDPSocket: bind6 %d errno %d (%s)", fd, errno, strerror(errno));
 424             return;
 425         }
 426     }
 427 }
 428
 429 // Setup DNS Proxy Skts in main kevent loop and set the skt options
 430 mDNSlocal void SetupDNSProxySkts(mDNS *const m, int fd[4])
 431 {
 432     int i;
 433     mStatus err;
 434     KQSocketSet *udpSS;
 435     KQSocketSet *tcpSS;
 436
 437     udpSS       = &m->p->UDPProxy.ss;
 438     tcpSS       = &m->p->TCPProxy.ss;
 439     udpSS->port = UnicastDNSPort;
 440     tcpSS->port = UnicastDNSPort;
 441
 442     LogMsg("SetupDNSProxySkts: %d, %d, %d, %d", fd[0], fd[1], fd[2], fd[3]);
 443
 444     // myKQSocketCallBack checks for proxy and calls the m->p->ProxyCallback instead of mDNSCoreReceive
 445     udpSS->proxy = mDNStrue;
 446     err = SetupUDPProxySocket(m, fd[0], udpSS, AF_INET, mDNSfalse);
 447     if (err)
 448         LogMsg("SetupDNSProxySkts: ERROR!! UDPv4 Socket");
 449
 450     err = SetupUDPProxySocket(m, fd[1], udpSS, AF_INET6, mDNSfalse);
 451     if (err)
 452         LogMsg("SetupDNSProxySkts: ERROR!! UDPv6 Socket");
 453
 454     err = SetupTCPProxySocket(m, fd[2], tcpSS, AF_INET, mDNSfalse);
 455     if (err)
 456         LogMsg("SetupDNSProxySkts: ERROR!! TCPv4 Socket");
 457
 458     err = SetupTCPProxySocket(m, fd[3], tcpSS, AF_INET6, mDNSfalse);
 459     if (err)
 460         LogMsg("SetupDNSProxySkts: ERROR!! TCPv6 Socket");
 461
 462     for (i = 0; i < 4; i++)
 463         dp_listener[i] = fd[i];
 464 }
 465
 466 // Create and bind the DNS Proxy Skts for use
 467 mDNSexport void mDNSPlatformInitDNSProxySkts(mDNS *const m, ProxyCallback UDPCallback, ProxyCallback TCPCallback)
 468 {
 469     int dpskt[4];
 470
 471     dpskt[0] = socket(AF_INET,  SOCK_DGRAM,  IPPROTO_UDP);
 472     dpskt[1] = socket(AF_INET6, SOCK_DGRAM,  IPPROTO_UDP);
 473     dpskt[2] = socket(AF_INET,  SOCK_STREAM, IPPROTO_TCP);
 474     dpskt[3] = socket(AF_INET6, SOCK_STREAM, IPPROTO_TCP);
 475
 476     // Close all DNS Proxy skts in case any of them are invalid
 477     if (!ValidSocket(dpskt[0]) || !ValidSocket(dpskt[1]) ||
 478         !ValidSocket(dpskt[2]) || !ValidSocket(dpskt[3]))
 479     {
 480         if (ValidSocket(dpskt[0]))
 481             close(dpskt[0]);
 482         if (ValidSocket(dpskt[1]))
 483             close(dpskt[1]);
 484         if (ValidSocket(dpskt[2]))
 485             close(dpskt[2]);
 486         if (ValidSocket(dpskt[3]))
 487             close(dpskt[3]);
 488     }
 489
 490     BindDPSocket(dpskt[0], AF_INET);
 491     BindDPSocket(dpskt[1], AF_INET6);
 492     BindDPSocket(dpskt[2], AF_INET);
 493     BindDPSocket(dpskt[3], AF_INET6);
 494
 495     LogInfo("mDNSPlatformInitDNSProxySkts: Opened Listener Sockets for DNS Proxy : %d, %d, %d, %d",
 496              dpskt[0], dpskt[1], dpskt[2], dpskt[3]);
 497
 498     m->p->UDPProxyCallback = UDPCallback;
 499     m->p->TCPProxyCallback = TCPCallback;
 500
 501     SetupDNSProxySkts(m, dpskt);
 502 }
 503
 504 mDNSexport void mDNSPlatformCloseDNSProxySkts(mDNS *const m)
 505 {
 506     (void) m;
 507     int i;
 508     for (i = 0; i < 4; i++)
 509         close(dp_listener[i]);
 510     LogInfo("mDNSPlatformCloseDNSProxySkts: Closing DNS Proxy Listener Sockets");
 511 }
 512
 513 mDNSexport void mDNSPlatformDisposeProxyContext(void *context)
 514 {
 515     ProxyTCPInfo_t *ti;
 516     TCPSocket *sock;
 517     KQSocketSet *kq;
 518
 519     if (!context)
 520         return;
 521
 522     ti = (ProxyTCPInfo_t *)context;
 523     sock = &ti->sock;
 524
 525     kq = &sock->ss;
 526     if (kq->sktv4 != -1)
 527     {
 528         shutdown(kq->sktv4, 2);
 529         mDNSPlatformCloseFD(&kq->kqsv4, kq->sktv4);
 530     }
 531     if (kq->sktv6 != -1)
 532     {
 533         shutdown(kq->sktv6, 2);
 534         mDNSPlatformCloseFD(&kq->kqsv6, kq->sktv6);
 535     }
 536     if (kq->closeFlag)
 537         *kq->closeFlag = 1;
 538
 539     if (ti->reply)
 540         freeL("ProxyTCPInfoLen", ti->reply);
 541     freeL("ProxyTCPContext", ti);
 542 }
 543